Biology of nitric oxide signaling

101013 Portal periodicos CAPES

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[Signal Transduction In Critical Care Medicine Scientific Reviews]

Critical Care Medicine

Issue Volume 28(4) Supplement April 2000 pp N37-N52

Copyright copy 2000 Lippincott Williams amp Wilkins Inc

Publication Type [Signal Transduction In Critical Care Medicine Scientific Reviews]

ISSN 0090-3493

Accession 00003246-200004001-00005

Keywords cell signaling cytotoxicity dinitrogen trioxide nitric oxide nitration nitrosation nitrosothiols oxidation peroxynitrite superoxide radical

Biology of nitric oxide signaling

Liaudet Lucas MD Soriano Francisco Garcia MD Szaboacute Csaba MD PhD

Section Editor(s) Luce John M MD FCCM Yaffe M ichael B MD PhD Fink M itchell P MD FCCM

Author InformationUniversity of California San Francisco

From Inotek Corporation Beverly MA (Dr Szaboacute) Department of Surgery New Jersey Medical School UMDNJ Newark NJ (Drs Soriano and Szaboacute) and the Division

of Pulmonary Biology Childrens Hospital Research Foundation Cincinnati OH (Dr Liaudet)

Supported in part by a grant from the National Institutes of Health (R01 GM60915) (Dr Szaboacute)

Address correspondence to Dr Csaba Szaboacute Inotek Corporation Suite 419E 100 Cummings Center Beverly MA 01915 Email szabocsabaaolcom

Abstract

The free radical nitric oxide (NO) has emerged in recent years as a fundamental signaling molecule for the

maintenance of homeostasis as well as a potent cytotoxic effector involved in the pathogenesis of a wide range

of human diseases Although this paradoxical fate has generated confusion separating the biological actions of

NO on the basis of its physiologic chemistry provides a conceptual framework which helps to distinguish between

the beneficial and toxic consequences of NO and to envision potential therapeutic strategies for the future

Under normal conditions NO produced in low concentration acts as a messenger and cytoprotective

(antioxidant) factor via direct interactions with transition metals and other free radicals Alternatively when the

circumstances allow the formation of substantial amounts of NO and modify the cellular microenvironment

(formation of the superoxide radical) the chemistry of NO will turn into indirect effects consecutive to the

formation of dinitrogen trioxide and peroxynitrite These reactive nitrogen species will in turn mediate both

oxidative and nitrosative stresses which form the basis of the cytotoxicity generally attributed to NO relevant to

the pathophysiology of inflammation circulatory shock and ischemiareperfusion injury

Over the past decade following the discovery that mammalian cells have the ability to synthesize the free

radical nitric oxide (NO) research focusing on this simple diatomic molecule has led to a formidable amount of

publications determining that NO plays significant roles in most fields of life sciences (1) However at the turn of

the millennium a number of questions regarding NO biology still remain unanswered the most challenging and

confusing problem being set by the ambivalent character of NO While being a critical signaling messenger

involved in the regulation of a vast array of physiologic functions NO also has the ability to turn into a major

cytotoxic effector involved in a number of pathophysiologic conditions and in the pathogenesis of a growing list

of human diseases (2 3) On a clinical viewpoint such paradoxical fate of NO is particularly troublesome when

one considers manipulating NO availability as a potential therapeutic option in different pathologic conditions

Reducing or increasing NO availability in a given circumstance may inevitably be associated with both beneficial

effects and deleterious consequences

In addition further adding to an already complex situation some theoretical misconceptions have also

contributed to the confusion surrounding the perplexing biological functions of NO For instance the proper

effects of NO have often and abusively been assimilated to those of a family of NO-derived molecules

collectively termed reactive nitrogen species (RNS) which all possess their unique biochemical characteristics

(4) thus creating serious confusion Another frequent misconception is that NO as a free radical is a highly

reactive molecule with a very short lifetime Although the free radical nature of NO constitutes the chemical

basis of its biological activity its reactivity is relatively weak and basically NO interacts only with transition

metals oxygen and other free radicals (5) This low reactivity combined to a high lipophilicity confers to NO the

potential to diffuse away from its point of origin and thereby to carry out its function as a messenger molecule

(6)

What then will determine the role of NO either as a signaling device or a potent cytotoxin Or what will

decide between the good or the ugly face of NO The unique parameter to be considered here is the type of

chemistry associated with NO which depends both on the flux of NO and on the surrounding chemical

microenvironment In turn the particular NO chemistry will determine the biological response under given

conditions (7) It is convenient to categorize the chemical reactions of NO into direct effects consecutive to the

reactions involving NO itself and indirect effects resulting from the formation of peroxynitrite (ONOO-) and

dinitrogen trioxide (N2O3) following the interaction of NO with the superoxide radical (O2-) and oxygen

respectively (Fig 1) (6) As a general rule the direct effects of NO prevail in conditions of low and brief NO

production and mainly support protective and signaling functions which are consistent with the chemical biology

of NO encountered under normal physiologic conditions (6) In contrast indirect effects will rather occur under

high and sustained flux of NO as noted under pathophysiologic circumstances and will essentially result in toxic

consequences which include oxidation nitrosation (adjunction of NO+) and nitration (adjunction of NO2+)

reactions (6 7) It appears then that the type of NO chemistry prevailing at a particular moment in time is the key

feature that determines its biological actions We will review the direct and indirect effects of NO which at




least considered from our viewpoint represent the critical basis to the understanding of the roles played by NO

in both the healthy and the aggressed organism

Figure 1 Physiologic chemistry of nitric oxide (NO) separation between direct and indirect effects

BIOLOGICAL CHEMISTRY OF NO INSIGHT INTO REGULATORY AND CYTOTOXIC ACTIONS

Overview of NO Synthases

NO is synthesized from the guanidino group of L-arginine by a family of enzymes termed NO synthases (NOS)

from which three isoforms have been described and cloned All three isoforms use nicotinamide

diphosphonucleotide (NADPH) and molecular oxygen as cosubstrates and all contain the following prosthetic

groups flavin-adenine mononucleotide flavin mononucleotide tetrahydrobiopterin zinc and a heme complex

ironprotoporphyrin IX (8) Classically the NOS isoforms have been subdivided into a constitutive (cNOS) and an

inducible nitric oxide synthase (iNOS) activity (1) a terminology which tends to become obsolete since the

observation that the constitutive isoforms may be induced in some circumstances and that inducible NOS may

be constitutively expressed in some cells (9) A further classification denotes the cell type where the different

isoforms were first described and their dependence on a Ca2+ transient (gt~100 nM) for full enzyme activity (1)

Thus cNOS encompasses the calcium-dependent isoforms found in endothelial (eNOS or NOS 3) and neuronal

(nNOS or NOS 1) cells producing small (picomolar) amounts of NO for short periods In contrast the macrophage-

type iNOS expressed on stimulation by various proinflammatory signals is maintained in a constant activated state

independently from calcium and thus produces high (nM) amounts of NO for extended periods of time (2)

Accordingly the direct effects of NO are essentially determined by the activity of cNOS isoforms whereas

indirect effects become relevant in conditions of iNOS expression However this assumption is not always true

since significant cytotoxicity resulting from indirect effects of NO may be observed in absence of iNOS

expression as in a wide range of neurologic diseases and in the early phase of ischemia-reperfusion injury where

NO is provided respectively by nNOS and eNOS Conversely iNOS expression is not always correlated with tissue

injury the best example being pregnancy during which iNOS is expressed in the placenta and fetal organs

producing substantial amounts of NO without apparent toxic consequences (10)

Direct Effects of NO (Table 1)

Table 1 Direct effects of nitric oxide (NO)

Reactions of NO With Metals The direct interactions of NO with transition metals leads to three types of

reactions including a) the formation of stable nitrosyl complexes via covalent reactions between NO and metal

ions b) redox reactions between NO and metal ions and c) NO binding to iron-sulfur clusters in proteins (6)

Formation of stable nitrosyl complexes mainly occurs with ferrous iron in heme-containing proteins resulting in a

displacement of the iron out of the plane of the porphyrinic ring (11) This conformational change may result in

totally opposite effects (activation or inhibition) depending on the affected protein

Guanylyl Cyclase The best characterized reaction between NO and a heme protein is the NO-dependent

activation of soluble guanylyl (formerly also termed guanylate) cyclase (sGC) leading to its translocation to the

plasma membrane (12 13) Activation of sGC requires low concentrations of NO (EC50 100 nM) and as such




represents the most significant physiological effect associated with the low NO flux derived from cNOS (12 13)

sGC catalyzes the conversion of guanosine triphosphate into cyclic guanosine monophosphate (cGMP) which in

turn proceeds through several downstream elements including cGMP-dependent protein kinases cGMP-

regulated phosphodiesterases and cGMP-gated ion channels (13) cGMP-dependent protein kinases phosphorylate

target proteins including the Ca2+-ATPase-regulating protein phosopholamban and the inositol triphosphate

receptor as well as various Ca2+ transporters channel proteins and receptors leading basically to a decrease of

intracellular free Ca2+ (13-15) Cyclic nucleotide phosphodiesterases (PDE) catalyze the hydrolysis of cGMP and

cyclic adenosine monophosphate (cAMP) into GMP and AMP CGMP acts on several isoforms of PDE either as an

inhibitor (PDE3 isoform) or an activator (PDE 2 PDE 5 PDE 6 isoforms) and thus directly influences the

degradation of cAMP providing an important cross-talk between NO-cGMP and cAMP signaling pathways (13)

Finally cyclic nucleotidegated ion channels are nonspecific cation channels found in several tissues such as the

retina where they are involved in the mechanisms of phototransduction (16) Overall the activation of sGC by NO

constitutes the major pathway of NO signaling involved in the regulation of a vast array of physiologic functions

including relaxation of vascular and nonvascular smooth muscle inhibition of platelet aggregation inhibition of

leukocyte adhesion to the endothelium and signal transduction in the nervous system to name but a few (1)

Cyclooxygenase Another heme protein target for NO is cyclooxygenase (COX) which converts arachidonic

acid into prostaglandins prostacyclin and thromboxane A2 COX exists as a constitutive (COX 1) and inducible

(COX 2) isoforms the latter being up-regulated in inflammatory conditions on stimulation by diverse cytokines (17)

It is now well established that the COX and NO pathways are interrelated providing one important cross-talk in

the regulation of the inflammatory response (17) Several reports (18-21) have shown that NO acts as an activator

of COX activity while others (22-24) found NO-mediated COX inhibition It appears that different types of NO

chemistry dictate its effects on COX activity The heme iron in active COX is in the ferric form and reduction to

the ferrous state inhibits COX activity (6) as may occur in the presence of the superoxide radical (21 25) In low

concentrations NO has the ability to modulate the redox form of COX converting the ferrous iron to its active

ferric form as well as to scavenge superoxide thereby enhancing COX activity (6) At higher concentration NO

forms a stable nitrosyl adduct with ferric iron in COX inhibiting enzyme activity (22) Also formation of

peroxynitrite in these conditions has been shown to irreversibly inhibit prostacyclin synthase via nitration of the

heme thiolate center of the enzyme (26) In addition to modulating COX activity NO also inhibits lipoxygenase

which converts arachidonic acid into various leukotrienes such as the potent chemoattractant leukotriene B4 via

binding to nonheme iron at the active site of the enzyme (27) Although not yet fully elucidated it is likely that

the interactions between the two cosignals represented by NO and bioactive metabolites of arachidonate play a

major regulatory role both in normal and pathologic conditions by modulating a number of processes such as

vasoreactivity platelet aggregation leukocyte-endothelium interactions and chemoattraction of inflammatory

cells

Cytochrome P-450 NO also interacts with the heme moiety of cytochrome P-450 resulting in reversible

enzymatic inhibition by preventing binding of oxygen to the catalytic site (28 29) NO thus directly interferes

with the cytochrome P-450-dependent metabolism of various compounds such as steroid hormones and

eicosanoids (29) For instance inhibition of cytochrome P-450-dependent formation of the potent vasoconstrictor

20-hydroxycosatetraenoic acid (20-HETE) has been shown to contribute to the vasodilator effect of NO (30)

Additionally NO-mediated inhibition of cytochrome P-450 can affect the pharmacokinetics of a number of drugs

with a potential important impact on the therapy of critically ill patients This mechanism has been determined to

alter the metabolism of sedatives and analgesics during experimental sepsis (31)

NO Synthases NO binds to the heme prosthetic group of NO synthase itself preventing oxygen binding and L-

arginine activation resulting in NOS inhibition (32-34) The oxidation state of the heme iron appears critical in

determining the magnitude of NOS inhibition by NO the ferric state increasing markedly this negative feedback

regulation (33) In this regard a potential role of tetrahydrobiopterin a cofactor of NO synthase might be to

limit this autoinhibition by favoring the formation of the ferrous heme (33 35) The constitutive isoforms of NOS

are much more sensitive to this autoregulation than the inducible NOS (33 35) which suggests that in conditions

associated with iNOS expression the enhanced NO flux from iNOS might reduce the activity of cNOS Several

studies (36 37) have indicated that selectively blocking iNOS activity improved endothelial-dependent vasodilation

in animal models of endotoxic shock Since iNOS expression in the vascular wall is also associated with a reduced

formation of the endothelium-derived hyperpolarizing factor (38) this supports an important mechanistic role of

iNOS-derived NO in the endothelial dysfunction associated with a number of diseases such as septic shock and

atherosclerosis

Catalase At high concentrations (gt10 microM) NO has been shown to inhibit catalase through the formation of a

ferric nitrosyl adduct in the heme moiety of the enzyme (39 40) and to reduce the consumption of hydrogen

peroxide (H2O2) which has been proposed as a mechanism potentiating H2O2 bactericidal activity (41) as well as

the cytotoxicity of activated macrophages against tumor cells (40) In addition such mechanism has been

determined to promote altered vasoactive responses in the pulmonary arteries (42) Alternatively at much lower

concentration of NO catalase and H2O2 consume NO through the formation of an intermediary product called

complex I reacting with NO to yield HNO2 (6 43) This suggests that under physiologic conditions the catalase

and H2O2 might serve to control the availability of NO thereby playing a critical role in the regulation of the

direct effects of NO (6)

Cytochrome Oxidase The mitochondria are sensitive targets of NO and reactive nitrogen species When

considering the direct effects of NO the only relevant biological action of NO per se is the reversible inhibition

of cytochrome oxidase (44 45) the terminal complex of the mitochondrial electron transport chain Cytochrome

oxidase contains 2 heme moieties (cytochrome a and cytochrome a3) and 2 copper centers NO forms a stable




nitrosyl adduct with reduced heme a3 the oxygen-binding site of cytochrome oxidase (45) A number of in vitro

studies using purified cytochrome oxidase isolated mitochondria or whole cells in culture showed that the

inhibition of cytochrome oxidase by NO is extremely rapid and competitive with oxygen (44 46-49) suggesting

that the physiologic role of NO in mitochondria may be to increase the Km of respiration for oxygen (44) In line

with this hypothesis inhibition of the basal (constitutive) NO production in vivo has been determined to increase

oxygen consumption in different animal species either at the whole-body level or in particular organs including

the kidney heart and skeletal muscle (50-54) Also it is noteworthy that mitochondria were recently shown to

express a particular isoform of NO synthase (mtNOS) pointing to a well regulated NO production in this organelle

These concordant data support the emerging concept that NO may act as a ubiquitous regulator of oxygen

consumption and oxidative phosphorylation in mitochondria (45 55)

NO Redox Reactions With Metals Reactions of NO With Hemoglobin NO rapidly reacts with metal oxygen

complexes the most prevalent of these reactions being the oxidation of NO by oxyhemoglobin (oxyHb) yielding

methemoglobin (metHb) and nitrate This reaction is considered to be the main route for NO elimination and is

also the basis of a prevalent NO assay (56) The NO scavenging effects of oxyHb has prompted the evaluation of

free hemoglobin solutions as pressor agents in critically ill patients (57) However recent evidence (58) indicated

that the oxidation of NO by oxyHb is only of little physiologic significance Instead addition reactions of NO and

hemoglobin including the formation of FeII nitrosyl hemoglobin as well as of an S-nitroso-adduct of hemoglobin

are emerging as fundamental mechanisms in the regulation of NO chemistry tissue oxygenation and

microcirculation (58 59) NO reacts with deoxyhemoglobin to form a stable nitrosyl adduct preferably with the

[alpha] subunit of hemoglobin It has been suggested that NO-bound Hb [alpha] can promote the allosteric

decrease in oxygen affinity of the hemoglobin tetramer in the peripheral circulation thus increasing oxygen

release in tissues by increasing P50 (60) Also S-nitrosation of a specific cysteine residue in the [beta] chain of

hemoglobin during its passage in the lung followed by NO release in the peripheral circulation consecutive to

deoxygenation has been proposed to play a role in blood flow regulation in the physiologic oxygen gradient (61)

Reactions of NO With High Valent Metals A major direct effect of NO is its reaction with high oxidation states

of metals and metal oxygen complexes which are severely damaging species formed in various conditions such as

ischemia-reperfusion and circulatory shock (7) Reaction of hemoproteins (hemoglobin cytochromes) with

hydrogen peroxide results in the formation of the highly toxic ferryl cation (Fe4+ = O) (62) In the presence of NO

these hypervalent metal-oxygen complexes are reduced (Fe3+ + NO2-) abating their oxidizing potential (6) NO

also inhibits some iron catalyzed reactions leading to the production of powerful oxidants as the hydroxyl radical

OHbull For example M iles and colleagues (63) have demonstrated that NO markedly reduces the formation of OH

resulting from the O2--driven Fenton reaction These data indicate that NO on its own possesses a unique

antioxidant potential which accounts in major part for the NO-dependent protection against oxidant-induced

cytotoxicity (64)

Reaction of NO With Iron-Sulfur Clusters NO can directly bind to iron-sulfur centers 4Fe-4S in proteins

giving rise to an iron-sulfur nitrosyl complex resulting in enzyme inhibition (6) This chemistry is essentially

relevant to the NO-mediated inhibition of the cytosolic and mitochondrial aconitases (65) These enzymes contain

a 4Fe-4S cluster in which only 3 iron atoms have cysteine coordination The noncysteine coordination is

displaced by NO binding resulting in an inactive 3Fe-4S cluster (6) NO ability to block mitochondrial aconitase

a key enzyme of the citric acid cycle results in reduced energy production and thus constitutes an important

cytotoxic effect attributable to NO alone (65) This effect has been shown to be markedly enhanced in acidic

conditions such as those prevailing in shock of various etiologies indicating that even low levels of NO may have a

profound negative influence on intracellular energetics in such circumstances (65)

NO also interacts with the 4Fe-4S cluster of cytoplasmic aconitase also referred to as the iron-responsive-

binding protein (IRB) IRB binds to specific RNA strands present in mRNA transcripts (called the iron responsive

elements [IRE]) of proteins involved in iron metabolism (66) Disruption of the iron sulfur cluster of IRB increases

its binding to IRE resulting in a repression of ferritin synthesis and an increased synthesis of transferrin receptor

the consequence being an increased cellular uptake of iron (6 67) Alternatively NO may reduce free

intracellular iron by decreasing iron release from ferritin via inhibition of NADPH oxidase assembly a key enzyme

in the process of iron release from ferritin (6) Overall these balanced effects probably play a role in NO-

mediated cytostasis and cytotoxicity in view of the importance of iron in cell growth and as a catalyst of

oxidative chemistry (6)

Reactions of NO With Free Radicals

Due to its free radical nature NO rapidly reacts with other free radicals An example of such reactions is the

interaction between NO and a protein-bound tyrosyl radical in ribonucleotide reductase leading to inhibition of

DNA synthesis (68) which represents an important mechanism of NO-mediated cytotoxicity against pathogens and

tumor cells (69) Most significantly NO interactions with free radicals have a profound impact on lipid chemistry

Lipid peroxidation is a chain reaction initiated by various oxidizing species such as peroxynitrite hydroxyl radical

and hypervalent metallooxo complexes altering biomembranes and leading to the formation of various

proinflammatory lipid mediators (6) Lipid peroxidation results in the formation of lipid hydroperoxyl radicals

(LOObull) which in turn oxidize polyunsaturated fatty acids into lipid alkoxyl radicals (Lbull) further converted to new

hydroperoxyl radicals resulting in a self-amplifying cycle of lipid peroxidation (70) NO has a direct scavenging

effect on hydroperoxyl radicals yielding a transient ROONO species which gives after homolytic cleavage an

alkoxyl radical (RObull) and nitrogen dioxide (NO2) (71) leading to chain termination This scavenging property

confers to NO a major role in the cellular defense against oxidative stress (6 70) Thus NO prevents by such

interactions the oxidation of low-density lipoproteins in endothelial cells and macrophages (72 73) which appears




as an important protective mechanism against the development of atherosclerosis (72)

Indirect Effects of NO

While most of the direct effects of NO prevail in conditions of low NO flux allowing NO to carry its function

as a major regulatory messenger the metabolic fate of NO will turn into mostly indirect effects when NO flux

becomes sustained and enhanced mainly as a consequence of iNOS expression In such conditions NO gives rise

to a series of compounds collectively termed RNS which all possess their own biochemical characteristics In

these situations the prevailing chemistry will be that of nitrosation (adjunction of NO+) nitration (adjunction of

NO2+) and oxidation reactions Most if not all of these indirect effects of NO are dependent on the reactions

of NO with dioxygen and superoxide giving rise to dinitrogen trioxide and peroxynitrite

Reaction of NO With Oxygen In aqueous solutions NO decays to nitrite (NO2-) by a reaction with oxygen via

steps involving the generation of NO2 and a potent nitrosating species dinitrogen trioxide (N2O3) (6) The rate of

this reaction being inversely proportional to the square of NO concentration its significance remains probably

marginal under physiologic conditions (6) However due to the lipophilic character of both NO and oxygen the

reaction is markedly accelerated in the hydrophobic compartment of biological membranes (74) where formation

of N2O3 may increase by a factor of 15000 in conditions of high NO production (10) indicating that N2O3 can

become a significant nitrosating agent in specific conditions and specific locations

The biological targets of N2O3 include amines (formation of N-nitrosamines) and thiols (formation of S-

nitrosothiols) (6) The generation of N-nitrosamines has been proposed as a potential link between NO and

carcinogenesis and might be an important contributor of cancer development in long term inflammatory diseases

(75) S-nitrosothiols have been identified both in plasma and different cell systems in the form of either low

molecular weight (S-nitrosoglutathione and S-nitroso-cysteine) (76 77) or S-nitroso adducts of proteins containing

cysteine moieties (78) Due to their relative stability (half-lives from minutes to hours) and their ability to donate

NO S-nitrosothiols act as major storage and carrier systems for NO (79) Stamler and colleagues (80) have thus

demonstrated that NO circulates as an S-nitroso adduct of serum albumin whose plasma concentration may reach

5 to 6 microM Transport of NO in the form of S-nitrosylated hemoglobin appears to play a major regulatory role in the

microcirculation (81) Also it has been shown that S-nitrosothiols are stored by platelets and released during

platelet-neutrophil interactions which could modulate vascular inflammation (82) Although the mechanisms

allowing the formation and the degradation of these S-nitrosothiols remain unclear recent data indicate that the

redox states of copper ions might play a fundamental role in these processes (83) In addition an important

feature of S-nitrosothiols metabolism is the formation of secondary S-nitroso adducts via S-transnitrosation

reactions which determines the distribution of NO among cellular thiol pools (84)

Biological Functions of S-nitrosothiols S-nitrosothiols possess a wide range of biological functions part of

which only being related to NO generation S-nitros(yl)ation of proteins is increasingly recognized as a ubiquitous

regulatory reaction comparable to phosphorylation and S-nitrosothiols appear to play significant roles in a large

number of biological processes (78) (Table 2)

Table 2 Indirect effects of nitric oxide (NO) Targets and consequences of S-nitrosation reactions (see text for

references)



Receptors and Ion Channels Important biotargets of S-nitrosylation reactions are located in the cellular

membranes including receptors and ion channels (78) Desensitization of the neuronal NMDA receptor-channel

complex through inhibition of its redox modulatory site via S-nitrosylation has been suggested to play a major

neuroprotective role (85 86) which might counterbalance the neurotoxicity elicited by NO produced in

response to NMDA stimulation (87 88) Similarly S-nitrosylation of glucocorticoid receptor leading to decreased

steroid binding has been recently proposed to explain the failure of glucocorticoids to exert their

antiinflammatory effects in conditions associated with enhanced NO production such as septic shock (89) S-

nitrosylation also alters plasma membrane potentials by influencing ion current through specific channels

Activation of calcium-dependent potassium channels in vascular smooth muscle via S-nitrosylation has been thus

shown to partially account for the NO-mediated vascular relaxation (90) In the heart and skeletal muscle

activation of the calcium release channel (ryanodine receptor) via poly-S-nitrosylation leading to Ca2+ release

from the sarcoplasmic reticulum is considered a fundamental mechanism to regulate force in striated muscle (91

92) S-nitrosylation also appears to regulate the cardiac L-type Ca2+ channel with conflicting reports however

showing either activation (93) or inhibition (94) of cardiac calcium currents by S-nitrosothiols

Intracellular Metabolic Pathways A number of intracellular processes are influenced by widespread S-

nitrosylation of metabolic proteins S-nitrosylation of critical thiol groups inhibits creatine kinase (95 96) and

glyceraldehyde-3-phosphate deshydrogenase (GAPDH) (97 98) which may affect the anaerobic generation of ATP

However in the case of GAPDH S-nitrosylation also leads to a nonenzymatic automodification by ADP-ribosylation

(97 99) which prevents irreversible inhibition by oxidants such as H2O2 (100 101) indicating that S-nitrosylation

of GAPDH profoundly affects glucose metabolism in conditions of nitrosative and oxidative stress Since in such

conditions energy production via the mitochondrial electron transport chain may be impaired maintenance of

the glycolytic pathway is obligatory to maintain a minimal production of high energy phosphates In this regard

the blockade of GAPDH activity could represent a critical event leading to full energetic deprivation and eventual

necrosis of the cell In addition to GAPDH other metabolic enzymes have been shown to be inhibited by S-

nitrosylation including alcohol-deshydrogenase implying a link between NO and ethanol metabolism (102) as well

as ornithine decarboxylase the initial enzyme in the polyamine synthetic pathway which may be an important

mechanism allowing NO to limit cell proliferation (103)

Signal Amplification Systems S-nitrosylation has been recently demonstrated to be an important mechanism

modulating downstream signaling from different amplification systems most notably protein kinase C (PKC) and G

proteins (3) S-nitrosylation of critical thiol residues in PKC has been shown to alter its kinase activity and thus

to inhibit PKC-dependent signaling cascade (104) which involves both the stimulation of specific responses in

differentiated cells and regulation of growth and proliferation in undifferentiated cells (105) For instance NO-

dependent inhibition of PKC delta is a required mechanism for endothelial cell migration and proliferation induced

by vascular endothelial growth factor implying an important role of NO in the regulation of angiogenesis (106)

These data showing S-nitrosylation-mediated inhibition of PKC contrast with recent reports indicating a direct

activation of PKC by NO (107-110) which suggests that the ultimate modulation of PKC signaling by NO depends on

a finely tuned balance between two opposite influences

Furthermore S-nitrosylation reactions also influence signaling through membrane guanine nucleotide binding

proteins (G proteins) (111) resulting in the activation of pertussis-toxin-sensitive G proteins (112) and the

protooncogene p21ras (113 114) as well as inhibition of G proteins of the Gi and Gq family (115) Such

mechanisms have been shown to play a role in various biological processes such as bradykinin signaling (115)

modification of synaptic efficacy in the central nervous system (116) and cholinergic control of heart rate (117)

Finally S-nitrosylation has also been identified as a possible mechanism regulating signaling from protein tyrosine

kinase (118 119) tyrosine phosphatase (119) and adenylate cyclase (120 121)

DNA and Transcription Factors NO has emerged in recent years as an important modulator of gene

expression through its ability to alter the structural integrity of transcription factors In particular control of

gene expression by NO is currently regarded as a fundamental process in the regulation of the inflammatory

response Modulation of the activity of the transcription factor NF[kappa]B appears pivotal in these mechanisms

Several studies have demonstrated an inhibition of NF[kappa]B activity after S-nitrosylation and stabilization of its

inhibitor I[kappa]B[alpha] (122 123) as well as inhibition of the DNA-binding activity of NF[kappa]B itself via S-

nitrosylation of its p50 subunit (124-127) In turn this effect may reduce cellular activation upon exposure to

proinflammatory signals (128) This mechanism appears to account for the decreased expression of the adhesion

molecules VCAM-1 and ICAM-1 by endothelial and smooth muscle cells upon exposure to various cytokines (129-

131) as well as the reduced production of proinflammatory cytokines during acute lung injury (132) In addition to

NF[kappa]B several other transcription factors have been shown to be regulated by S-nitrosylation including

activator protein-1 (AP-1) (133) c-jun (134) CREB (135) and c-Myb (136)

In contrast to the above-mentioned data recent evidence has indicated that NO may directly enhance

NF[kappa]B activity (108 137 138) thereby providing an important signal to amplify the inflammatory response For

instance in a mouse model of hemorrhagic shock Hierholzer et al (139) have shown that induction of iNOS is

associated with activation of NF[kappa]B in concert with activation of STAT 3 and increases in IL-6 and G-CSF

mRNA in the lung and liver pointing to an NO-dependent upregulation of the inflammatory response In addition

NO-dependent activation of NF[kappa]B in the heart has been suggested to be a fundamental event in the late

phase of ischemic preconditioning (140) Although these above mentioned effects of NO on NF[kappa]B appear

contradictory at times one can hypothesize that in conditions of moderate flux of NO activation of NF[kappa]B

would predominate to give an amplifying signal on the inflammatory cascade in particular by increasing NO

production through an enhanced NF[kappa]B-dependent expression of iNOS At higher flux of NO S-nitrosylation

reactions would become prevailing and reduce NF[kappa]B activation providing a negative feedback to avoid an




overwhelming uncontrolled inflammatory response

Cellular Redox Status The cellular redox status a fundamental signaling device in cellular homeostasis is

profoundly affected by S-nitrosylation reactions Reduced glutathione (GSH) due to its high affinity for both

reactive nitrogen species and reactive oxygen intermediates is a central biomolecule involved in the cellular

defense against nitrosative and oxidative stress (6) Depletion of GSH has been shown to increase NO-dependent

cytotoxicity by a 100-fold factor (141 142) S-nitrosothiols including the S-nitroso-adduct of GSH itself (GSNO)

may inhibit several enzymatic pathways involved in glutathione metabolism (111) including glutathione-S-

transferase (143) glutathione reductase (144) and [gamma]-glutamyl-cysteine synthetase (145) In addition S-

nitrosylation reactions have been linked to an activation of the hexose monophosphate shunt (146) which

supplies reducing equivalents indispensable to replenish the cellular GSH stores These effects are also to be

integrated with the recent finding that NO per se increases GSH levels through both an enhanced expression of

[gamma]-glutamyl-cysteine synthetase (147) and induction of the x-c aminoacid transport system (148) increasing

cysteine uptake It appears then that in circumstances associated with high NO production nitrosative stress

enhances the cellular susceptibility to oxidant-mediated damage providing an important cycle of cytotoxic

amplification in inflammatory conditions In contrast the beneficial influence of NO at low concentration on

intracellular GSH represents another aspect of NO acting as an antioxidant and cytoprotective molecule

Reaction of NO With Superoxide Anion NO rapidly reacts with the superoxide radical (O2-) to yield

peroxynitrite (ONOO-) a highly reactive oxidant species at near diffusion limited rate of 19 times 1010 M -1s-1 (149)

The half-life of peroxynitrite is short (~1 sec) but sufficient to allow significant interactions with most

biomolecules (Table 3) In aqueous solutions peroxynitrite is in equilibrium with its protonated form

peroxynitrous acid which spontaneously isomerizes into nitrate via the formation of a bent form of

transperoxynitrous acid (149) It is currently considered that the reactions associated with peroxynitrite are only

partly mediated by peroxynitrite itself (150) but rather by an electronically excited isomer of peroxynitrous acid

as well as products of the rapid interaction of peroxynitrite and carbon dioxide (151) such as

nitrosoperoxicarbonate nitrocarbonate and the free radicals bullNO2 and CO3bull- (151-153)

Table 3 Indirect effects of nitric oxide (NO) Peroxynitrite Targets and biological actions

While the sources of NO are essentially restricted to the different NOS isozymes superoxide arises from

different candidates mainly the xanthinexanthine oxidase system and NADPH oxidase derived from inflammatory

cells (154) In noninflammatory cells most of the superoxide is generated in mitochondria following electron leak

along the respiratory chain (155) In this regard the reversible inhibition of cytochrome oxidase by NO may result

in enhanced electron leak increasing superoxide production and peroxynitrite generation (156) which in turn

may have a significant impact on mitochondrial respiration Finally under particular circumstances such as

arginine deprivation (157 158) exposition to high concentrations of lipoproteins (159) or redox cycling

xenobiotics (160) NO synthase itself may serve as a superoxide generator indicating that NOS can function as a

peroxynitrite synthase in some conditions (4)

Several authors have attempted to quantify the interaction between NO and O2- in vivo and have

demonstrated that maximal peroxynitrite generation and oxidative stress occurred at equimolar fluxes of both NO

and O2- while peroxynitrite formation was significantly reduced when the flux of one radical exceeded the other

(27 63) It has been proposed that the reduced oxidative stress associated with excess NO or O2- was related to

the NO or O2- mediated conversion of peroxynitrite into N2O3 (63 161 162) thereby converting a potent oxidant

into a nitrosative species Accordingly these data suggest that excess NO or O2- may act to modulate

peroxynitrite-mediated tissue damage in vivo (27 163) It is also important to emphasize that the interaction

between NO and O2- depends on the competing reaction of O2

- with superoxide dismutase (SOD) which catalyzes

the dismutation of O2- into H2O2 SOD exists as a cytosolic (CuZn SOD) mitochondrial (MnSOD) and secreted or

extracellular SOD (ECSOD) (150 164) The rate of reaction of SOD with O2- (2 times 109 M -1s-1) is slighltly lower than

that of O2- and NO but due to the high concentration of SOD (up to 10 microM in the cytosol and 20 microM in the

mitochondria) most of the O2- will be channeled toward dismutation products (5 7 149) Accordingly only high

concentrations of NO (around 10 microM) will be able to compete for O2- with SOD to yield peroxynitrite

One can conclude from the above discussion that peroxynitrite generation will be restricted to specific




locations (where O2- and NO concentrations are matched) in conditions of high NO output (sufficient to

compete with SOD) Therefore if one considers two distinct sources of both NO and O2- one can predict that

excess NO near its source will dictate nitrosative chemistry (formation of N2O3) as well as direct effects of NO (6)

Diffusing away from its source NO dilutes and thus becomes able to react with O2- to form peroxynitrite

indicating that most of the peroxynitrite will be formed near the O2- source (6) This may have important

implications in the cytotoxicity elicited by inflammatory cells Different time courses and rates of O2- and NO

production will allow preferential biological targeting while limiting deleterious consequences on the cell of

origin In this regard it appears that endothelial cells are probably critically situated to suffer from much of the

peroxynitrite-mediated oxidant damage in inflammatory conditions (7 27)

Physiologic Actions of Peroxynitrite Although peroxynitrite is a potent cytotoxin involved in a number of

pathophysiologic conditions some physiologic functions of peroxynitrite have also been identified which are

similar to those of NO including vasodilation (165) inhibition of platelet aggregation (166) and leukocyte adhesion

to the endothelium (167) Small amounts of peroxynitrite may be formed under normal conditions from the

reaction of cNOS-derived NO and superoxide generated in mitochondria In turn peroxynitrite reacts with

sugars such as glucose fructose glycerol and mannitol (168 169) as well as with low molecular weight and

protein-bound thiols (170) to form adducts able to act as NO donors and activate guanylatecyclase (171 172) In

addition peroxynitrite may also exert direct physiological effects independent from NO generation For

instance peroxynitrite has been shown to dilate cerebral arteries in a cGMP-independent way by activating ATP-

sensitive potassium channels (173)

Cytotoxic Effects of Peroxynitrite While only limited information is available regarding the potential

physiological actions of peroxynitrite an increasing body of evidence supports that peroxynitrite exerts major

deleterious influence oxidizing lipids thiols protein and nucleic acids in numerous pathophysiologic conditions

such as localized inflammation (174-176) ischemia-reperfusion (177 178) and shock of various etiologies (179-182)

Peroxynitrite and Lipid Peroxidation Peroxynitrite is a potent initiator of lipid peroxidation by abstracting a

hydrogen atom from polyunsaturated fatty acids resulting in the formation of lipid hydroperoxyradicals which

propagate the free radical reaction (70 183) Peroxynitrite-mediated oxidation of low-density lipoprotein is thus

regarded as a critical aspect of the pathogenesis of atherosclerosis (184-186) Also recent evidence (187-189)

revealed that peroxynitrite plays a critical role in inflammatory diseases of the nervous system by initiating

peroxidation of myelin lipids leading to demyelination NO serves as a potent terminator of these radical chain

propagations and thus depending on the relative fluxes of NO and O2- NO can both stimulate or abrogate

oxidant reactions in membranes (70 163) The interactions of peroxynitrite with membrane lipids may also lead to

the formation of various nitrated lipids (163) which may have significant biological properties by acting as

mediators of signal transduction (190)

Peroxynitrite and Thiol Groups Another important feature of peroxynitrite-mediated oxidation is the

interactions of peroxynitrite with low molecular weight and protein-bound thiols In particular the reaction of

GSH with peroxynitrite has been demonstrated to play a major role in the cellular defense against peroxynitrite

(191) and accordingly the susceptibility of cells to peroxynitrite toxicity largely depends on the amount of

intracellular GSH Depletion of endogenous GSH with L-buthionine-sulfoximine has been shown to markedly

enhance peroxynitrite-mediated tissue injury in animal models of endotoxic shock and localized inflammation (192

193) A relationship between GSH depletion and enhanced peroxynitrite toxicity has also been proposed to

contribute to the development of various neurodegenerative diseases such as Parkinsons diseases (194)

Peroxynitrite also oxidizes protein-bound thiols which can affect a number of zinc thiolate centers notably in the

nucleus Peroxynitrite may thus inhibit several transcription factors or DNA repair enzymes using Zn2+ finger

motifs (Zn2+ complexed by cysteine-sulfur ligands) for specific DNA binding (195-197) Similar alterations have been

shown to play a role in the regulation of skeletal muscle contraction and relaxation by modulating the activity of

sarcoplasmic calcium-ATPase (198)

Peroxynitrite and Mitochondrial Respiration It is now established that mitochondria are particularly sensitive

targets to NO-mediated cytotoxicity However it has become evident over the past few years that most of this

toxic potential is related to peroxynitrite rather than NO itself (45 199 200) Using submitochondrial fractions it

has been demonstrated that peroxynitrite exposure results in an irreversible inhibition of complex I (succinate

deshydrogenase) complex II (NADHubiquinone oxidoreductase) complex V (ATP synthetase) and cisaconitase

(201-206) via binding and inactivation of the Fe-S clusters of the enzymes (45) An important aspect of

mitochondrial inhibition by NO-peroxynitrite is the possibility that peroxynitrite produced in mitochondria is a

consequence of NO binding and reversible inhibition of cytochrome oxidase leading to enhanced mitochondrial

O2- generation and peroxynitrite production (45 207) Although the high concentration of MnSOD in

mitochondria should efficiently compete with NO for superoxide peroxynitrite has the ability to inhibit MnSOD by

nitration of a critical tyrosine residue (208) and thus to prevent the breakdown of locally produced superoxide

In addition to causing inhibition of respiratory enzymes peroxynitrite also oxidizes several mitochondrial proteins

(209) and membrane lipids (210) which may lead to the opening of the permeability transition pore (PTP) (211)

resulting in calcium efflux (212) mitochondrial depolarization and release of cytochrome c into the cytoplasm

(213 214)

Inhibition of mitochondrial enzymes and opening of the PTP by peroxynitrite has been associated with both

necrotic and apoptotic type cellular death (45) Experimental evidence now exists that such alterations are

mechanistically involved in the development of a number of pathophysiologic conditions associated with an




enhanced formation of NO In the central nervous system peroxynitrite-mediated mitochondrial damage is

considered a key feature of degenerative (eg Alzheimers disease) and inflammatory (eg multiple sclerosis)

diseases as well as a major mechanism of ischemic damage to the brain (215) Inhibition of mitochondrial

respiration also plays a role in the vascular and multiple organ failure complicating hemorrhagic (181) and

endotoxic shock (179) and is implicated in ischemia-reperfusion injury for instance in the myocardium (216 217)

Peroxynitrite and DNA Activation of PARS In addition to its direct effects on mitochondria peroxynitrite

also impairs cellular energetics by an indirect way implicating DNA damage and activation of the nuclear enzyme

poly (ADP-ribose) synthetase (PARS) a pathway increasingly recognized as a major mechanism of NOperoxynitrite-

mediated cytotoxicity (218-220) Peroxynitrite may produce two types of DNA damage the first one being

modification of DNA bases via both oxidation and nitration reactions the second one being the induction of nicks

and breaks in the DNA strand (221) DNA single-strand breakage is the obligatory trigger for the activation of PARS

which then catalyzes the cleavage of its substrate nicotinamide dinucleotide (NAD+) into ADP-ribose and

nicotinamide (220) PARS covalently attaches ADP-ribose to various nuclear proteins and rapidly depletes the

cellular NAD+ stores slowing the rate of glycolysis electron transport and ATP formation resulting in cell

dysfunction and death via the necrotic pathway (220) Recent studies using various PARS inhibitors as well as

genetically engineered animals lacking the gene encoding PARS have demonstrated that peroxynitrite-mediated

PARS activation is a major pathway mediating tissue injury in various pathophysiologic states such as diabetes

mellitus (222) circulatory shock (181 223) and reperfusion of ischemic organs (178 224 225)

NO Peroxynitrite and Apoptosis Cellular death may occur via two distinct pathways necrotic or apoptotic

While necrosis is associated with overwhelming cellular injury leading to membrane disruption release of cellular

debris and promoting a secondary inflammatory response apoptosis results in DNA fragmentation membrane

blebbing and the formation of apoptotic bodies which are subject of rapid phagocyosis without eliciting an

inflammatory reaction (226) Apoptosis is a genetically controlled program of cell death indispensable for normal

development and tissue homeostasis as well as for the elimination of cells that have sustained genetic damage

(226) In the past few years the role of NO in the process of apoptosis has been the subject of considerable

research with reports showing both pro- and antiapoptotic effects of NO (3 4 6 226) (Table 4)

Table 4 Role of nitric oxide (NO) and peroxynitrite in apoptosis (see text for references)

NO can induce apoptosis in a variety of cell lines including macrophages (227) thymocytes (228) ventricular

myocytes (229) vascular endothelial cells (230) and pancreatic beta cells (231) Accumulation of the tumor

suppressor gene p53 able to induce growth arrest or apoptosis in DNA-damaged cells has been suggested to play

a role in the process of NO-induced apoptosis (229 232-234) NO not only induces p53 expression but also

reduces its degradation by inhibiting the ubiquitinproteasome pathway (235) In addition NO was reported to

activate caspases (236 237) a family of proteolytic enzymes able to cleave a wide range of proteins leading to the

characteristic changes of apoptosis Recent data indicate that peroxynitrite rather than NO itself may be the

species responsible for NO-dependent apoptosis This has been demonstrated in lung fibroblasts (238)

thymocytes (239) HL-60 cells (240 241) neural cells (242 243) beta islet cells (244-246) and human neutrophils

(247) Potential mechanisms of peroxynitrite-dependent apoptosis involve DNA injury (238 247) and mitochondrial

damage in particular opening of the permeability transition pore resulting in cytochrome c efflux into the

cytoplasm (135 211 248) and subsequent activation of caspases (135 239 240) Repression of the anti-apoptotic

proteins Bcl-2 and Bcl-Xl associated with increased levels of the proapoptotic protein Bax have also been

suggested to be involved in the process of peroxynitrite-mediated apoptosis leading to acute rejection of cardiac

transplants in mice (249) Similar mechanisms might be operative in humans where heart allograft rejection has

been correlated with iNOS induction peroxynitrite formation and apoptotic cell death (250) Several studies have

shown that the susceptibility of cells to peroxynitrite-dependent apoptosis is critically dependent on the redox

cellular status with significant protection afforded by high levels of glutathione or ascorbic acid (251 252) as

well as on the energetic state of the cell Apoptosis switched to necrosis if the cellular insult was severe enough

to deplete the cellular stores in high-energy phosphates thereby blocking the energy-consuming apoptotic

program (253 254)

In sharp contrast with the above-described mechanisms NO has been shown to protect against apoptosis in a

number of experimental conditions via both cGMP-dependent and independent mechanisms For instance

antigen-induced apoptosis in splenic B lymphocytes is inhibited by NO via a cGMP-mediated prevention of the

drop in bcl-2 levels (255) and NO protects PC12 cells from serum-deprivation induced apoptosis by inhibiting

caspase signaling through cGMP formation (256) NO is also known to directly inhibit several members of the

caspase family in vitro most notably caspase-3 via S-nitrosylation of a critical thiol residue (257-260) a mechanism

that might explain the beneficial antiapoptotic influence of inhaled NO against hyperoxia-induced apoptosis in rat

lungs (261) Recent results (262) also suggested that NO may be important to maintain lytic capacity of human NK

cells by protecting them from activation-induced apoptosis by decreasing the activation of the transcription

factor NFAT thereby limiting tumor necrosis factor-[alpha] expression Furthermore NO may induce the

expression of stress proteins such as heme oxygenase-1 (HO-1) able to limit apoptosis under oxidative stress

(263) and can reduce anoxia-induced apoptosis by inhibiting the release of cytochrome c from mitochondria

(264)


linkperiodicoscapesgovbrez67periodicoscapesgovbrsfxlcl41url_ver=Z3988-2004ampurl_ctx_fmt=infofifmtkevmtxctxampctx_enc=infoofiencUTF-8ampchellip 1027

(264)

In summary NO mainly via the formation of peroxynitrite has the ability to induce both necrosis and

apoptosis The decision between both types of death depends on the type of cell involved the degree of

aggression the level of energetic deprivation and the cellular redox status under a given circumstance Such

processes relevant to indirect effects of NO associated with enhanced NO production contrast with the mainly

protective direct actions of NO both as an antioxidant and antiapoptotic molecule

Nitrative Chemistry of Peroxynitrite Nitration of Tyrosine Residues Another important consequence of

peroxynitrite generation is the nitration of the phenolic ring of tyrosine to yield 3-nitrotyrosine (3-NT) (265)

which has long been considered as a specific footprint of peroxynitrite formation in vivo However recent data

have indicated that 3-NT may also be formed via pathways independent from peroxynitrite including the reaction

of nitrite with hypochlorous acid (266) and the reaction of myeloperoxidase with hydrogen peroxide (267)

Therefore 3-NT formation should be considered as a common marker of various processes associated with

nitrative stress rather than a specific consequence of peroxynitrite generation (265) Of note nitration of

tyrosine is a selective process influenced by the local protein environment such as the presence of acidic amino

acids which may direct nitration toward specific tyrosine residues (268)

Tyrosine nitration may affect both protein structure and function Tyrosine nitration of MnSOD in

mitochondria leads to enzyme inhibition (208) with the possible consequence to favor peroxynitrite generation in

this organelle Disorganization of cell architecture by nitration of cytoskeletal proteins such as actin and

neurofilament L (269-271) may play a role in the myocardial dysfunction associated with inflammatory myocarditis

(272) and in the alterations of motor neurons in amyotrophic lateral sclerosis (270 271) In addition nitration of a

critical tyrosine residue in tyrosinehydroxylase has been associated with cerebral dopamine deficiency in a mouse

model of Parkinsons disease (273) and nitration of surfactant protein A may be involved in the development of

various lung inflammatory disorders (272) Similar alterations have been shown to inhibit the formation of

prostacyclin from prostacyclin synthase (26) which represents another important feature of the crosstalk

between NO and arachidonic acid metabolism Finally nitration of protein tyrosine residues may have an

important impact on tyrosine kinase-dependent downstream signaling nitration of specific tyrosine kinase

substrates has been shown to inhibit their phosphorylation in vitro (274 275)

Direct and Indirect Effects of NO Potential Therapeutic Implications

Separating between direct and indirect effects of NO not only allows to define the various mechanisms of

action but also helps to devise potential therapeutic strategies for different pathologies This is a particularly

important issue to the critical care physician who daily faces patients with various forms of shock ischemia-

reperfusion injury and overwhelming systemic inflammation In such conditions limiting the indirect effects of NO

appears as a viable therapeutic option to reduce tissue injury and improve survival At the same time

maintenance or even enhancement of the direct effects of NO would be suitable eg to reduce oxidant-

mediated organ damage improve tissue perfusion reduce leukocyte adhesion and platelet aggregation

For this purpose one can envision that several distinct strategies might be developed in the next few years

including a) selective inhibition of iNOS which has been determined experimentally to reduce the

pathophysiologic alterations associated with various kinds of inflammatory diseases and circulatory shock (276) A

potential pitfall of such approach however might be the reduction of an important mechanism of defense against

invading pathogens as supported by the recent demonstration that the mortality of septic shock is enhanced in

iNOS-deficient mice in comparison with wild-type animals (277) Also it has been shown that inhibition of iNOS

enhances viral replication and leads to increased lethality in systemic viral infection models (278) This suggests

that the potential benefits of selective iNOS inhibition may be canceled out by independent deleterious actions

of iNOS blockade at least in conditions associated with microbial infections b) Therapies aimed at limited

peroxynitrite generation or actions including scavengers removing excess NO or superoxide as well as

peroxynitrite scavengers Although specific peroxynitrite scavengers are still in relatively early stage of

development it is noteworthy that the recently developed compound mercaptoethylguanidine which combines

properties of selective iNOS inhibition and peroxynitrite scavenging has been shown to provide significant

benefits in experimental models of inflammation and shock (176 182) c) Approaches targeting delayed effectors

of NOperoxynitrite cytotoxicity In this regard recent developments have clearly indicated that inhibition of

PARS is an efficient strategy to limit tissue injury in conditions where peroxynitrite formation results from

enhanced production of both NO and superoxide Such approach is also strongly supported by the protection

observed in PARS knockout mice exposed to various forms of shock inflammation and reperfusion injury (220) d)

Therapies combining several strategies Due to the redundancy in the mechanisms of inflammation sequential

targeting of the above-mentioned pathways will be probably more effective than targeting a single pathway

CONCLUSIONS

In this review we have attempted to present the current state of knowledge regarding the multiple

biological actions of NO Although these multifaceted actions may seem contradictory at first glance a critical

analysis of the physiologic chemistry of NO provides a conceptual framework which helps to distinguish between

beneficial versus detrimental actions of NO Depending on the rate and timing of NO production as well as the

chemical microenvironment (eg presence of superoxide redox status of the cell) NO either acts as a direct

signaling messenger and cytoprotective molecule or as an indirect cytotoxic effector via the formation of

various reactive nitrogen species Improving our understanding of the biological chemistry of NO and its

congeners will undoubtedly lead to the development of novel therapeutic strategies for a wide range of human

pathologies



pathologies

REFERENCES

1 Nathan C Xie QW Nitric oxide synthases roles tolls and controls Cell 1994 78915-918 Full Text

Bibliographic Links [Context Link]

2 Szabo C Alterations in nitric oxide production in various forms of circulatory shcok New Horizons 1995 32-32


3 Lane P Gross SS Cell signaling by nitric oxide Semin Nephrol 1999 19215-229 Bibliographic Links [Context

Link]

4 Patel RP McAndrew J Sellak H et al Biological aspects of reactive nitrogen species Biochim Biophys Acta

1999 1411385-400 Bibliographic Links [Context Link]

5 Beckman JS Koppenol WH Nitric oxide superoxide and peroxynitrite The good the bad and ugly Am J

Physiol 1996 271C1424-C1437 Bibliographic Links [Context Link]

6 Wink DA Mitchell JB Chemical biology of nitric oxide Insights into regulatory cytotoxic and cytoprotective

mechanisms of nitric oxide Free Radic Biol Med 1998 25434-456 Full Text Bibliographic Links [Context Link]

7 Grisham MB JourdHeuil D Wink DA Nitric oxide I Physiological chemistry of nitric oxide and its

metabolitesimplications in inflammation Am J Physiol 1999 276G315-G321 Bibliographic Links [Context Link]

8 Stuehr DJ Mammalian nitric oxide synthases Biochim Biophys Acta 1999 1411217-230 Bibliographic Links

[Context Link]

9 M ichel T Feron O Nitric oxide synthases Which where how and why J Clin Invest 1997 1002146-2152


10 M iller MJ Sandoval M Nitric Oxide III A molecular prelude to intestinal inflammation Am J Physiol 1999

276G795-G799 Bibliographic Links [Context Link]

11 Cooper CE Nitric oxide and iron proteins Biochim Biophys Acta 1999 1411290-309 Bibliographic Links

[Context Link]

12 Murad F Nitric oxide signaling would you believe that a simple free radical could be a second messenger

autacoid paracrine substance neurotransmitter and hormone Recent Prog Horm Res 1998 5343-59


13 Denninger JW Marletta MA Guanylate cyclase and the NOcGMP signaling pathway Biochim Biophys Acta


14 Schmidt HH Walter U NO at work Cell 1994 78919-925 Full Text Bibliographic Links [Context Link]

15 Marin J Rodriguez-Martinez MA Role of vascular nitric oxide in physiological and pathological conditions

Pharmacol Ther 1997 75111-134 Full Text Bibliographic Links [Context Link]

16 Zagotta WN Siegelbaum SA Structure and function of cyclic nucleotide-gated channels Annu Rev Neurosci


17 Salvemini D Regulation of cyclooxygenase enzymes by nitric oxide Cell Mol Life Sci 1997 53576-582 [Context

Link]

18 Salvemini D M isko TP Masferrer JL et al Nitric oxide activates cyclooxygenase enzymes Proc Natl Acad Sci U

S A 1993 907240-7244 Full Text Bibliographic Links [Context Link]

19 Salvemini D Seibert K Masferrer JL et al Endogenous nitric oxide enhances prostaglandin production in a




model of renal inflammation J Clin Invest 1994 931940-1947 Bibliographic Links [Context Link]

20 Corbett JA Kwon G Turk J35 al IL-1 beta induces the coexpression of both nitric oxide synthase and

cyclooxygenase by islets of Langerhans Activation of cyclooxygenase by nitric oxide Biochem 1993 3213767-

13770 [Context Link]

21 Davidge ST Baker PN Laughlin MK et al Nitric oxide produced by endothelial cells increases production of

eicosanoids through activation of prostaglandin H synthase Circ Res 1995 77274-283 Ovid Full Text


22 Kanner J Harel S Granit R Nitric oxide an inhibitor of lipid oxidation by lipoxygenase cyclooxygenase and

hemoglobin Lipids 1992 2746-49 Bibliographic Links [Context Link]

23 Stadler J Harbrecht BG Di Silvio M et al Endogenous nitric oxide inhibits the synthesis of cyclooxygenase

products and interleukin-6 by rat Kupffer cells J Leukoc Biol 1993 53165-172 Bibliographic Links [Context Link]

24 Tsai AL Wei C Kulmacz RJ Interaction between nitric oxide and prostaglandin H synthase Arch Biochem

Biophys 1994 313367-372 Full Text Bibliographic Links [Context Link]

25 Kelner MJ Uglik SF Mechanism of prostaglandin E2 release and increase in PGH2PGE2 isomerase activity by

PDGF involvement of nitric oxide Arch Biochem Biophys 1994 312240-243 [Context Link]

26 Zou M Yesilkaya A Ullrich V Peroxynitrite inactivates prostacyclin synthase by hemethiolate-catalyzed

tyrosine nitration Drug Metab Rev 1999 31343-349 Bibliographic Links [Context Link]

27 Grisham MB Granger DN Lefer DJ Modulation of leukocyte-endothelial interactions by reactive metabolites

of oxygen and nitrogen Relevance to ischemic heart disease Free Radic Biol Med 1998 25404-433 Full Text


28 Veihelmann A Brill T Blobner M et al Inhibition of nitric oxide synthesis improves detoxication in

inflammatory liver dysfunction in vivo Am J Physiol 1997 273G530-G536 Bibliographic Links [Context Link]

29 Takemura S M inamiyama Y Imaoka S et al Hepatic cytochrome P450 is directly inactivated by nitric oxide

not by inflammatory cytokines in the early phase of endotoxemia J Hepatol 1999 301035-1044 Full Text


30 Alonso-Galicia M Drummond HA Reddy KK et al Inhibition of 20-HETE production contributes to the vascular

responses to nitric oxide Hypertension 1997 29320-325 Ovid Full Text Bibliographic Links [Context Link]

31 Muller CM Scierka A Stiller RL et al Nitric oxide mediates hepatic cytochrome P450 dysfunction induced by

endotoxin Anesthesiology 1996 841435-1442 Ovid Full Text Bibliographic Links [Context Link]

32 Vickroy TW Malphurs WL Inhibition of nitric oxide synthase activity in cerebral cortical synaptosomes by

nitric oxide donors Evidence for feedback autoregulation Neurochem Res 1995 20299-304 Bibliographic Links

[Context Link]

33 Griscavage JM Hobbs AJ Ignarro LJ Negative modulation of nitric oxide synthase by nitric oxide and nitroso

compounds Adv Pharmacol 1995 34215-234 Bibliographic Links [Context Link]

34 Rengasamy A Johns RA Regulation of nitric oxide synthase by nitric oxide Mol Pharmacol 1993 44124-128


35 Hyun J Komori Y Chaudhuri G et al The protective effect of tetrahydrobiopterin on the nitric oxide-

mediated inhibition of purified nitric oxide synthase Biochem Biophys Res Commun 1995 206380-386 Full Text


36 Schwartz D Mendonca M Schwartz I et al Inhibition of constitutive nitric oxide synthase (NOS) by nitric

oxide generated by inducible NOS after lipopolysaccharide administration provokes renal dysfunction in rats J

Clin Invest 1997 100439-448 Bibliographic Links [Context Link]



37 Szabo C Bryk R Zingarelli B et al Pharmacological characterization of guanidinoethyldisulphide (GED) a novel

inhibitor of nitric oxide synthase with selectivity towards the inducible isoform Br J Pharmacol 1996 1181659-

1668 Bibliographic Links [Context Link]

38 Kessler P Popp R Busse R et al Proinflammatory mediators chronically downregulate the formation of the

endothelium-derived hyperpolarizing factor in arteries via a nitric oxidecyclic GMP-dependent mechanism

Circulation 1999 991878-1884 Ovid Full Text Bibliographic Links [Context Link]

39 Hoshino M Ozawa K Seki H et al Photochemistry of nitric oxide adducts of water-soluble iron(III) porphyrin

and ferrihemoproteins studie by nanosecond laser photolysis J Am Chem Soc 1993 1159568-9575 [Context Link]

40 Farias-Eisner R Chaudhuri G Aeberhard E et al The chemistry and tumoricidal activity of nitric

oxidehydrogen peroxide and the implications to cell resistancesusceptibility J Biol Chem 1996 2716144-6151


41 Smith AW Green J Eden CE et al Nitric oxide-induced potentiation of the killing of Burkholderia cepacia by

reactive oxygen species implications for cystic fibrosis J Med Microbiol 1999 48419-423 Bibliographic Links

[Context Link]

42 Mohazzab HK Fayngersh RP Wolin MS Nitric oxide inhibits pulmonary artery catalase and H202-associated

relaxation Am J Physiol 1996 271H1900-H1916 Bibliographic Links [Context Link]

43 Brown GC Reversible binding and inhibition of catalase by nitric oxide Eur J Biochem 1995 232188-191


44 Brown GC Cooper CE Nanomolar concentrations of nitric oxide reversibly inhibit synaptosomal respiration by

competing with oxygen at cytochrome oxidase FEBS Lett 1994 356295-298 [Context Link]

45 Brown GC Nitric oxide and mitochondrial respiration Biochim Biophys Acta 1999 1411351-369 Bibliographic

Links [Context Link]

46 Cleeter MW Cooper JM Darley-Usmar VM et al Reversible inhibition of cytochrome c oxidase the terminal

enzyme of the mitochondrial respiratory chain by nitric oxide Implications for neurodegenerative diseases FEBS

Lett 1994 34550-54 Full Text Bibliographic Links [Context Link]

47 Schweizer M Richter C Nitric oxide potently and reversibly deenergizes mitochondria at low oxygen tension

Biochem Biophys Res Commun 1994 204169-175 Full Text Bibliographic Links [Context Link]

48 Takehara Y Kanno T Yoshioka T et al Oxygen-dependent regulation of mitochondrial energy metabolism by

nitric oxide Arch Biochem Biophys 1995 32327-32 Full Text Bibliographic Links [Context Link]

49 Nishikawa M Sato EF Kuroki T et al Role of glutathione and nitric oxide in the energy metabolism of rat liver

mitochondria FEBS Lett 1997 415341-345 Full Text Bibliographic Links [Context Link]

50 Shen W Hintze TH Wolin MS Nitric oxide An important signaling mechanism between vascular endothelium

and parenchymal cells in the regulation of oxygen consumption Circulation 1995 923505-3512 Ovid Full Text


51 Shen W Xu X Ochoa M et al Role of nitric oxide in the regulation of oxygen consumption in conscious dogs

Circ Res 1994 751086-1095 Ovid Full Text Bibliographic Links [Context Link]

52 Laycock SK Vogel T Forfia PR et al Role of nitric oxide in the control of renal oxygen consumption and the

regulation of chemical work in the kidney Circ Res 1998 821263-1271 Ovid Full Text Bibliographic Links

[Context Link]

53 King CE Melinyshyn MJ Mewburn JD et al Canine hindlimb blood flow and O2 uptake after inhibition of

EDRFNO synthesis J Appl Physiol 1994 761166-1171 [Context Link]

54 Ishibashi Y Duncker DJ Zhang J et al ATP-sensitive K+ channels adenosine and nitric oxide-mediated




mechanisms account for coronary vasodilation during exercise Circ Res 1998 82346-359 Ovid Full Text


55 Bates TE Loesch A Burnstock G et al M itochondrial nitric oxide synthase a ubiquitous regulator of oxidative

phosphorylation Biochem Biophys Res Commun 1996 21840-44 [Context Link]

56 Gross SS Lane P Physiological reactions of nitric oxide and hemoglobin a radical rethink Proc Natl Acad Sci

U S A 1999 969967-9969 Full Text Bibliographic Links [Context Link]

57 Alayash AI Hemoglobin-based blood substitutes oxygen carriers pressor agents or oxidants Nat Biotechnol


58 Gow AJ Luchsinger BP Pawloski JR et al The oxyhemoglobin reaction of nitric oxide Proc Natl Acad Sci U S

A 1999 969027-9032 Full Text Bibliographic Links [Context Link]

59 Heyman SN Goldfarb M Darmon D et al Tissue oxygenation modifies nitric oxide bioavailability

Microcirculation 1999 6199-203 [Context Link]

60 Kosaka H Nitric oxide and hemoglobin interactions in the vasculature Biochim Biophys Acta 1999 1411370-


61 Stamler JS Jia L Eu JP et al Blood flow regulation by S-nitrosohemoglobin in the physiological oxygen

gradient Science 1997 2762034-2037 Full Text Bibliographic Links [Context Link]

62 Jourdheuil D M ills L M iles AM et al Effect of nitric oxide on hemoprotein-catalyzed oxidative reactions

Nitric Oxide 1998 237-44 Full Text Bibliographic Links [Context Link]

63 M iles AM Bohle DS Glassbrenner PA et al Modulation of superoxide-dependent oxidation and hydroxylation

reactions by nitric oxide J Biol Chem 1996 27140-47 Bibliographic Links [Context Link]

64 Kanner J Harel S Granit R Nitric oxide as an antioxidant Arch Biochem Biophys 1991 289130-136 Full Text


65 Gardner PR Costantino G Szaboacute C et al Nitric oxide sensitivity of the aconitases J Biol Chem 1997

27225071-25076 Bibliographic Links [Context Link]

66 Hentze MW Kuhn LC Molecular control of vertebrate iron metabolism mRNA-based regulatory circuits

operated by iron nitric oxide and oxidative stress Proc Natl Acad Sci U S A 1996 938175-8182 Full Text


67 Klausner RD Rouault TA Harford JB Regulating the fate of mRNA the control of cellular iron metabolism Cell

1993 7219-28 Full Text Bibliographic Links [Context Link]

68 Guittet O Rov B Lepoivre M Nitric oxide A radical molecule in quest of free radicals in proteins Cell Mol

Life Sci 1999 551054-1067 [Context Link]

69 Lepoivre M Flaman JM Bobe P et al Quenching of the tyrosyl free radical of ribonucleotide reductase by

nitric oxide Relationship to cytostasis induced in tumor cells by cytotoxic macrophages J Biol Chem 1994


70 Hogg N Kalyanaraman B Nitric oxide and lipid peroxidation Biochim Biophys Acta 1999 1411378-384


71 Atkinson R Aschmann SM Pitts JN Alkyl nitrate formation from the NOx-air photooxidantions of C2-C8 n-

alkanes J Phys Chem 1982 864563-4587 [Context Link]

72 Hogg N Struck A Goss SP et al Inhibition of macrophage-dependent low density lipoprotein oxidation by

nitric-oxide donors J Lipid Res 1995 361756-1762 Bibliographic Links [Context Link]



73 Malo-Ranta U Yla-Herttuala S Metsa-Ketela T et al Nitric oxide donor GEA 3162 inhibits endothelial cell-

mediated oxidation of low density lipoprotein FEBS Lett 1994 337179-183 Full Text Bibliographic Links

[Context Link]

74 Liu X M iller MJS Joshi MS et al Accelerated reaction of nitric oxide with O2 within the hydrophobic

interior of biological membranes Proc Natl Acad Sci U S A 1998 952175-2179 Full Text Bibliographic Links

[Context Link]

75 Hecht SS Approaches to cancer prevention based on an understanding of N-nitrosamine carcinogenesis Proc

Soc Exp Biol Med 1997 216181-191 Full Text Bibliographic Links [Context Link]

76 Gordge MP Addis P Noronha-Dutra AA et al Cell-mediated biotransformation of S-nitrosoglutathione

Biochem Pharmacol 1998 55657-665 Full Text Bibliographic Links [Context Link]

77 Kashiba M Kasahara E Chien KC et al Fates and vascular action of S-nitrosoglutathione and related

compounds in the circulation Arch Biochem Biophys 1999 363213-218 Full Text Bibliographic Links [Context

Link]

78 Broillet MC S-nitrosylation of proteins Cell Mol Life Sci 1999 551036-1042 [Context Link]

79 Butler AR Rhodes P Chemistry analysis and biological roles of S-nitrosothiols Anal Biochem 1997 2491-9

Full Text Bibliographic Links [Context Link]

80 Stamler JS Jaraki O Osborne J et al Nitric oxide circulates in mammalian plasma primarily as an S-nitroso

adduct of serum albumin Proc Natl Acad Sci U S A 1992 897674-7677 Full Text Bibliographic Links [Context

Link]

81 Jia L Bonaventura C Bonaventura J et al S-nitrosohaemoglobin a dynamic activity of blood involved in

vascular control Nature 1996 380221-226 Buy Now Bibliographic Links [Context Link]

82 Hirayama A Noronha-Dutra AA Gordge MP et al S-nitrosothiols are stored by platelets and released during

platelet-neutrophil interactions Nitric Oxide 1999 395-104 Full Text Bibliographic Links [Context Link]

83 Stubauer G Giuffre A Sarti P Mechanism of S-nitrosothiol formation and degradation mediated by copper

ions J Biol Chem 1999 27428128-28133 [Context Link]

84 Liu Z Rudd MA Freedman JE Loscalzo J S-Transnitrosation reactions are involved in the metabolic fate and

biological actions of nitric oxide J Pharmacol Exp Ther 1998 284526-534 [Context Link]

85 Lei SZ Pan ZH Aggarwal SK et al Effect of nitric oxide production on the redox modulatory site of the NMDA

receptor-channel complex Neuron 1992 81087-1099 Full Text Bibliographic Links [Context Link]

86 Lipton SA Choi YB Sucher NJ et al Neuroprotective versus neurodestructive effects of NO-related species

Biofactors 1998 833-40 Bibliographic Links [Context Link]

87 Sattler R Xiong Z Lu WY et al Specific coupling of NMDA receptor activation to nitric oxide neurotoxicity by

PSD-95 protein Science 1999 2841845-1848 Full Text Bibliographic Links [Context Link]

88 Yamauchi M Omote K Ninomiya T Direct evidence for the role of nitric oxide on the glutamate-induced

neuronal death in cultured cortical neurons Brain Res 1998 780253-259 Full Text Bibliographic Links [Context

Link]

89 Galigniana MD Piwien-Pilipuk G Assreuy J Inhibition of glucocorticoid receptor binding by nitric oxide Mol

Pharmacol 1999 55317-323 Bibliographic Links [Context Link]

90 Bolotina VM Najibi S Palacino JJ et al Nitric oxide directly activates calcium-dependent potassium channels

in vascular smooth muscle Nature 1994 368850-853 Bibliographic Links [Context Link]

91 Xu L Eu JP Meissner G Stamler JS Activation of the cardiac calcium release channel (ryanodine receptor) by

poly-S-nitrosylation Science 1998 279234-237 Full Text Bibliographic Links [Context Link]




92 Stoyanovsky D Murphy T Anno PR et al Nitric oxide activates skeletal and cardiac ryanodine receptors Cell

Calcium 1997 2119-29 [Context Link]

93 Campbell DL Stamler JS Strauss HC Redox modulation of L-type calcium channels in ferret ventricular

myocytes Dual mechanism regulation by nitric oxide and S-nitrosothiols J Gen Physiol 1996 108277-293


94 Hu H Chiamvimonvat N Yamagishi T et al Direct inhibition of expressed cardiac L-type Ca2+ channels by S-

nitrosothiol nitric oxide donors Circ Res 1997 81742-752 Ovid Full Text Bibliographic Links [Context Link]

95 Arstall MA Bailey C Gross WL et al Reversible S-nitrosation of creatine kinase by nitric oxide in adult rat

ventricular myocytes J Mol Cell Cardiol 1998 30979-988 Full Text Bibliographic Links [Context Link]

96 Kaasik A M inajeva A De Sousa E et al Nitric oxide inhibits cardiac energy production via inhibition of

mitochondrial creatine kinase FEBS Lett 1999 44475-77 Full Text Bibliographic Links [Context Link]

97 Molina y Vedia L McDonald B Reep B et al Nitric oxide-induced S-nitrosylation of glyceraldehyde-3-

phosphate dehydrogenase inhibits enzymatic activity and increases endogenous ADP-ribosylation [published

erratum appears in J Biol Chem 1993 2683016] J Biol Chem 1992 26724929-24932 Bibliographic Links [Context

Link]

98 Mohr S Hallak H de Boitte A et al Nitric oxide-induced S-glutathionylation and inactivation of

glyceraldehyde-3-phosphate dehydrogenase J Biol Chem 1999 2749427-9430 Bibliographic Links [Context Link]

99 Dimmeler S Brune B Characterization of a nitric-oxide-catalysed ADP-ribosylation of glyceraldehyde-3-

phosphate dehydrogenase Eur J Biochem 1992 210305-310 Bibliographic Links [Context Link]

100 Mohr S Stamler JS Brune B Posttranslational modification of glyceraldehyde-3-phosphate dehydrogenase by

S-nitrosylation and subsequent NADH attachment J Biol Chem 1996 2714209-4214 Bibliographic Links [Context

Link]

101 Schuppe-Koistinen I Moldeus P Bergman T et al S-thiolation of human endothelial cell glyceraldehyde-3-

phosphate dehydrogenase after hydrogen peroxide treatment Eur J Biochem 1994 2211033-1037 Bibliographic


102 Gergel D Cederbaum AI Inhibition of the catalytic activity of alcohol dehydrogenase by nitric oxide is

associated with S nitrosylation and the release of zinc Biochem 1996 3516186-16194 [Context Link]

103 Bauer PM Fukuto JM Buga GM et al Nitric oxide inhibits ornithine decarboxylase by S-nitrosylation


104 Gopalakrishna R Chen ZH Gundimeda U Nitric oxide and nitric oxide-generating agents induce a reversible

inactivation of protein kinase C activity and phorbol ester binding J Biol Chem 1993 26827180-185 Bibliographic


105 Toker A Signaling through protein kinase C Front Biosci 1998 3D1134-D1147 [Context Link]

106 Shizukuda Y Tang S Yokota R et al Vascular endothelial growth factor-induced endothelial cell migration

and proliferation depend on a nitric oxide-mediated decrease in protein kinase C delta activity Circ Res 1999

85247-256 Ovid Full Text Bibliographic Links [Context Link]

107 Yoshida K M izukami Y Kitakaze M Nitric oxide mediates protein kinase C isoform translocation in rat heart

during postischemic reperfusion Biochim Biophys Acta 1999 1453230-238 Bibliographic Links [Context Link]

108 Toyoshima T Kamijo R Takizawa K et al Nitric oxide up-regulates the expression of intercellular adhesion

molecule-1 on cancer cells Biochem Biophys Res Commun 1999 257395-399 Full Text Bibliographic Links

[Context Link]



109 Ping P Takano H Zhang J et al Isoform-selective activation of protein kinase C by nitric oxide in the heart

of conscious rabbits A signaling mechanism for both nitric oxide-induced and ischemia-induced preconditioning


110 Beauchamp P Richard V Tamion F et al Protective effects of preconditioning in cultured rat endothelial

cells effects on neutrophil adhesion and expression of ICAM-1 after anoxia and reoxygenation Circulation 1999


111 Gaston B Nitric oxide and thiol groups Biochim Biophys Acta 1999 1411323-333 Bibliographic Links

[Context Link]

112 Lander HM Sehajpal PK Novogrodsky A Nitric oxide signaling A possible role for G proteins J Immunol

1993 1517182-7187 [Context Link]

113 Lander HM Ogiste JS Pearce SF et al Nitric oxide-stimulated guanine nucleotide exchange on p21ras J

Biol Chem 1995 2707017-7020 Bibliographic Links [Context Link]

114 Lander HM Hajjar DP Hempstead BL et al A molecular redox switch on p21(ras) Structural basis for the

nitric oxide-p21(ras) interaction J Biol Chem 1997 2724323-4326 Bibliographic Links [Context Link]

115 M iyamoto A Laufs U Pardo C et al Modulation of bradykinin receptor ligand binding affinity and its coupled

G-proteins by nitric oxide J Biol Chem 1997 27219601-19608 Bibliographic Links [Context Link]

116 Hess DT Lin LH Freeman JA et al Modification of cysteine residues within G(o) and other neuronal proteins

by exposure to nitric oxide Neuropharmacology 1994 331283-1292 Full Text Bibliographic Links [Context Link]

117 Jumrussirikul P Dinerman J Dawson TM et al Interaction between neuronal nitric oxide synthase and

inhibitory G protein activity in heart rate regulation in conscious mice J Clin Invest 1998 1021279-1285


118 Akhand AA Pu M Senga T et al Nitric oxide controls src kinase activity through a sulfhydryl group

modification-mediated Tyr-527-independent and Tyr-416-linked mechanism J Biol Chem 1999 27425821-25826


119 Lander HM Sehajpal P Levine DM et al Activation of human peripheral blood mononuclear cells by nitric

oxide-generating compounds J Immunol 1993 1501509-1516 [Context Link]

120 McVey M Hill J Howlett A et al Adenylyl cyclase a coincidence detector for nitric oxide J Biol Chem


121 Vila-Petroff MG Younes A Egan J et al Activation of distinct cAMP-dependent and cGMP-dependent

pathways by nitric oxide in cardiac myocytes Circ Res 1999 841020-1031 Ovid Full Text Bibliographic Links

[Context Link]

122 Peng HB Libby P Liao JK Induction and stabilization of I kappa B alpha by nitric oxide mediates inhibition of

NF-kappa B J Biol Chem 1995 27014214-14219 Bibliographic Links [Context Link]

123 Katsuyama K Shichiri M Marumo F et al NO inhibits cytokine-induced iNOS expression and NF-kappaB

activation by interfering with phosphorylation and degradation of IkappaB-alpha Arterioscler Thromb Vasc Biol

1998 181796-1802 Ovid Full Text Bibliographic Links [Context Link]

124 DelaTorre A Schroeder RA Kuo PC Alteration of NF-kappa B p50 DNA binding kinetics by S-nitrosylation


125 delaTorre A Schroeder RA Bartlett ST et al Differential effects of nitric oxide-mediated S-nitrosylation on

p50 and c-jun DNA binding Surgery 1998 124137-142 [Context Link]

126 delaTorre A Schroeder RA Punzalan C et al Endotoxin-mediated S-nitrosylation of p50 alters NF-kappa B-

dependent gene transcription in ANA-1 murine macrophages J Immunol 1999 1624101-4108 [Context Link]

127 Matthews JR Botting CH Panico M et al Inhibition of NF-kappaB DNA binding by nitric oxide Nucleic Acids




Res 1996 242236-2242 Full Text Bibliographic Links [Context Link]

128 Raychaudhuri B Dweik R Connors MJ et al Nitric oxide blocks nuclear factor-kappaB activation in alveolar

macrophages Am J Respir Cell Mol Biol 1999 21311-316 Bibliographic Links [Context Link]

129 Shin WS Hong YH Peng HB et al Nitric oxide attenuates vascular smooth muscle cell activation by

interferon-gamma The role of constitutive NF-kappa B activity J Biol Chem 1996 27111317-11324 Bibliographic


130 Spiecker M Darius H Kaboth K et al Differential regulation of endothelial cell adhesion molecule expression

by nitric oxide donors and antioxidants J Leukoc Biol 1998 63732-739 Bibliographic Links [Context Link]

131 De Caterina R Libby P Peng HB et al Nitric oxide decreases cytokine-induced endothelial activation Nitric

oxide selectively reduces endothelial expression of adhesion molecules and proinflammatory cytokines J Clin

Invest 1995 9660-68 [Context Link]

132 Walley KR McDonald TE Higashimoto Y et al Modulation of proinflammatory cytokines by nitric oxide in

murine acute lung injury Am J Respir Crit Care Med 1999 160698-704 Bibliographic Links [Context Link]

133 Tabuchi A Sano K Oh E et al Modulation of AP-1 activity by nitric oxide (NO) in vitro NO-mediated

modulation of AP-1 FEBS Lett 1994 351123-127 Full Text Bibliographic Links [Context Link]

134 Klatt P Molina EP Lamas S Nitric oxide inhibits c-Jun DNA binding by specifically targeted S-

glutathionylation J Biol Chem 1999 27415857-15864 [Context Link]

135 Murphy MP Nitric oxide and cell death Biochim Biophys Acta 1999 1411401-414 Bibliographic Links

[Context Link]

136 Brendeford EM Andersson KB Gabrielsen OS Nitric oxide (NO) disrupts specific DNA binding of the

transcription factor c-Myb in vitro FEBS Lett 1998 42552-56 Full Text Bibliographic Links [Context Link]

137 Rodriguez-Ariza A Paine AJ Rapid induction of NF-kappaB binding during liver cell isolation and culture

Inhibition by L-NAME indicates a role for nitric oxide synthase Biochem Biophys Res Commun 1999 257145-148


138 Simpson CS Morris BJ Activation of nuclear factor kappaB by nitric oxide in rat striatal neurones differential

inhibition of the p50 and p65 subunits by dexamethasone J Neurochem 1999 73353-361 Buy Now Bibliographic


139 Hierholzer C Harbrecht B Menezes JM et al Essential role of induced nitric oxide in the initiation of the

inflammatory response after hemorrhagic shock J Exp Med 1998 187917-928 Bibliographic Links [Context Link]

140 Xuan YT Tang XL Banerjee S et al Nuclear factor-kappaB plays an essential role in the late phase of

ischemic preconditioning in conscious rabbits Circ Res 1999 841095-1109 Ovid Full Text Bibliographic Links

[Context Link]

141 Walker MW Kinter MT Roberts RJ et al Nitric oxide-induced cytotoxicity involvement of cellular resistance

to oxidative stress and the role of glutathione in protection Pediatr Res 1995 3741-49 [Context Link]

142 Petit JF Nicaise M Lepoivre M et al Protection by glutathione against the antiproliferative effects of nitric

oxide Dependence on kinetics of no release Biochem Pharmacol 1996 52205-212 Full Text Bibliographic


143 Clark AG Debnam P Inhibition of glutathione S-transferases from rat liver by S-nitroso-L-glutathione Biochem

Pharmacol 1988 373199-3201 Full Text Bibliographic Links [Context Link]

144 Becker K Gui M Schirmer RH Inhibition of human glutathione reductase by S-nitrosoglutathione Eur J

Biochem 1995 234472-478 Bibliographic Links [Context Link]

145 Han J Stamler JS Li HL et al Inhibition of g-glutamylcysteine synthetase by S-nitrosylation In Biology of




Nitric Oxide Vol IV Stamler JS Moncada S Higgs A (Eds) London Portland Press 1996 p 114 [Context Link]

146 Clancy RM Levartovsky D Leszczynska-Piziak J et al Nitric oxide reacts with intracellular glutathione and

activates the hexose monophosphate shunt in human neutrophils Evidence for S-nitrosoglutathione as a bioactive

intermediary Proc Natl Acad Sci U S A 1994 913680-3684 Full Text Bibliographic Links [Context Link]

147 Moellering D McAndrew J Patel RP et al The induction of GSH synthesis by nanomolar concentrations of

NO in endothelial cells A role for gamma-glutamylcysteine synthetase and gamma-glutamyl transpeptidase FEBS


148 Li H Marshall ZM Whorton AR Stimulation of cystine uptake by nitric oxide regulation of endothelial cell

glutathione levels Am J Physiol 1999 276C803-C811 Bibliographic Links [Context Link]

149 Koppenol WH The basic chemistry of nitrogen monoxide and peroxynitrite Free Radic Biol Med 1998 25385-

391 Full Text Bibliographic Links [Context Link]

150 Squadrito GL Pryor WA Oxidative chemistry of nitric oxide The roles of superoxide peroxynitrite and

carbon dioxide Free Radic Biol Med 1998 25392-403 Full Text Bibliographic Links [Context Link]

151 Uppu RM Squadrito GL Pryor WA Acceleration of peroxynitrite oxidations by carbon dioxide Arch Biochem


152 Lymar SV Jiang Q Hurst JK Mechanism of carbon dioxide-catalyzed oxidation of tyrosine by peroxynitrite

Biochemistry 1996 357855-7861 Bibliographic Links [Context Link]

153 Denicola A Freeman BA Trujillo M et al Peroxynitrite reaction with carbon dioxidebicarbonate kinetics

and influence on peroxynitrite-mediated oxidations Arch Biochem Biophys 1996 33349-58 [Context Link]

154 Brandes RP Koddenberg G Gwinner W et al Role of increased production of superoxide anions by NAD(P)H

oxidase and xanthine oxidase in prolonged endotoxemia Hypertension 1999 331243-1249 Ovid Full Text


155 Nohl H Generation of superoxide radicals as byproduct of cellular respiration Ann Biol Clin 1994 52199-204


156 Kroncke KD Fehsel K Kolb-Bachofen V Nitric oxide cytotoxicity versus cytoprotection-How why when

and where Nitric Oxide 1997 1107-120 Full Text Bibliographic Links [Context Link]

157 Xia Y Dawson VL Dawson TM et al Nitric oxide synthase generates superoxide and nitric oxide in arginine-

depleted cells leading to peroxynitrite-mediated cellular injury Proc Natl Acad Sci U S A 1996 936770-6774

[Context Link]

158 Xia Y Zweier JL Superoxide and peroxynitrite generation from inducible nitric oxide synthase in

macrophages Proc Natl Acad Sci U S A 1997 946954-6958 Full Text Bibliographic Links [Context Link]

159 Darley-Usmar VM Hogg N OLeary VJ et al The simultaneous generation of superoxide and nitric oxide can

initiate lipid peroxidation in human low density lipoprotein Free Radic Res Commun 1992 179-20 Bibliographic


160 Vasquez-Vivar J Martasek P Hogg N et al Endothelial nitric oxide synthase-dependent superoxide

generation from adriamycin Biochemistry 1997 3611293-11297 Bibliographic Links [Context Link]

161 Beckman JS Chen J Ischiropoulos H et al Oxidative chemistry of peroxynitrite Methods Enzymol 1994


162 Koppenol WH Moreno JJ Pryor WA et al Peroxynitrite a cloaked oxidant formed by nitric oxide and

superoxide Chem Res Toxicol 1992 5834-842 Bibliographic Links [Context Link]

163 Rubbo H Radi R Trujillo M et al Nitric oxide regulation of superoxide and peroxynitrite-dependent lipid

peroxidation Formation of novel nitrogen-containing oxidized lipid derivatives J Biol Chem 1994 26926066-26075





164 Stralin P Karlsson K Johansson BO et al The interstitium of the human arterial wall contains very large

amounts of extracellular superoxide dismutase Arterioscler Thromb Vasc Biol 1995 152032-2036 Ovid Full Text


165 Villa LM Salas E Darley-Usmar VM et al Peroxynitrite induces both vasodilatation and impaired vascular

relaxation in the isolated perfused rat heart Proc Natl Acad Sci U S A 1994 9112383-12387 Full Text


166 Brown AS Moro MA Masse JM et al Nitric oxide-dependent and independent effects on human platelets

treated with peroxynitrite Cardiovasc Res 1998 40380-388 [Context Link]

167 Lefer DJ Scalia R Campbell B et al Peroxynitrite inhibits leukocyte-endothelial cell interactions and

protects against ischemia-reperfusion injury in rats J Clin Invest 1997 99684-691 Bibliographic Links [Context

Link]

168 Moro MA Darley-Usmar VM Lizasoain I et al The formation of nitric oxide donors from peroxynitrite Br J


169 Dowell FJ Martin W The effects of peroxynitrite on rat aorta interaction with glucose and related

substances Eur J Pharmacol 1997 33843-53 Full Text Bibliographic Links [Context Link]

170 Wu M Pritchard KA Jr Kaminski PM et al Involvement of nitric oxide and nitrosothiols in relaxation of

pulmonary arteries to peroxynitrite Am J Physiol 1994 266H2108-H2113 Bibliographic Links [Context Link]

171 Tarpey MM Beckman JS Ischiropoulos H et al Peroxynitrite stimulates vascular smooth muscle cell cyclic

GMP synthesis FEBS Lett 1995 364314-318 Full Text Bibliographic Links [Context Link]

172 Mayer B Schrammel A Klatt P et al Peroxynitrite-induced accumulation of cyclic GMP in endothelial cells

and stimulation of purified soluble guanylyl cyclase Dependence on glutathione and possible role of S-nitrosation

J Biol Chem 1995 27017355-17360 Bibliographic Links [Context Link]

173 Wei EP Kontos HA Beckman JS Mechanisms of cerebral vasodilation by superoxide hydrogen peroxide and

peroxynitrite Am J Physiol 1996 271H1262-H1266 Bibliographic Links [Context Link]

174 Brahn E Banquerigo ML Firestein GS et al Collagen induced arthritis Reversal by mercaptoethylguanidine a

novel antiinflammatory agent with a combined mechanism of action J Rheumatol 1998 251785-1793 Bibliographic


175 Cuzzocrea S Zingarelli B Gilad E et al Protective effect of melatonin in carrageenan-induced models of

local inflammation Relationship to its inhibitory effect on nitric oxide production and its peroxynitrite scavenging

activity J Pineal Res 1997 23106-116 Bibliographic Links [Context Link]

176 Zingarelli B Cuzzocrea S Szabo C et al Mercaptoethylguanidine a combined inhibitor of nitric oxide

synthase and peroxynitrite scavenger reduces trinitrobenzene sulfonic acid-induced colonic damage in rats J

Pharmacol Exp Ther 1998 2871048-1055 Bibliographic Links [Context Link]

177 Endres M Scott G Namura S et al Role of peroxynitrite and neuronal nitric oxide synthase in the activation

of poly(ADP-ribose) synthetase in a murine model of cerebral ischemia-reperfusion Neurosci Lett 1998 24841-44


178 Cuzzocrea S Zingarelli B Costantino G et al Beneficial effects of 3-aminobenzamide an inhibitor of poly

(ADP-ribose) synthetase in a rat model of splanchnic artery occlusion and reperfusion Br J Pharmacol 1997


179 Zingarelli B Day BJ Crapo JD et al The potential role of peroxynitrite in the vascular contractile and

cellular energetic failure in endotoxic shock Br J Pharmacol 1997 120259-267 Bibliographic Links [Context

Link]



180 Szabo C The pathophysiological role of peroxynitrite in shock inflammation and ischemia-reperfusion injury

Shock 1996 679-88 [Context Link]

181 Szabo C Billiar TR Novel roles of nitric oxide in hemorrhagic shock Shock 1999 121-9 [Context Link]

182 Szabo A Hake P Salzman AL et al Beneficial effects of mercaptoethylguanidine an inhibitor of the inducible

isoform of nitric oxide synthase and a scavenger of peroxynitrite in a porcine model of delayed hemorrhagic

shock Crit Care Med 1999 271343-1350 Ovid Full Text Full Text Bibliographic Links [Context Link]

183 Radi R Beckman JS Bush KM et al Peroxynitrite-induced membrane lipid peroxidation the cytotoxic

potential of superoxide and nitric oxide Arch Biochem Biophys 1991 288481-487 Full Text Bibliographic Links

[Context Link]

184 Hogg N Darley-Usmar VM Graham A et al Peroxynitrite and atherosclerosis Biochem Soc Trans 1993 21358-


185 Moore KP Darley-Usmar V Morrow J et al Formation of F2-isoprostanes during oxidation of human low-

density lipoprotein and plasma by peroxynitrite Circ Res 1995 77335-341 Ovid Full Text Bibliographic Links

[Context Link]

186 Patel RP Diczfalusy U Dzeletovic S et al Formation of oxysterols during oxidation of low density lipoprotein

by peroxynitrite myoglobin and copper J Lipid Res 1996 372361-2371 Bibliographic Links [Context Link]

187 Shi H Noguchi N Xu Y et al Formation of phospholipid hydroperoxides and its inhibition by alpha-

tocopherol in rat brain synaptosomes induced by peroxynitrite Biochem Biophys Res Commun 1999 257651-656


188 Smith KJ Kapoor R Felts PA Demyelination The role of reactive oxygen and nitrogen species Brain Pathol


189 van der Veen RC Roberts LJ Contrasting roles for nitric oxide and peroxynitrite in the peroxidation of

myelin lipids J Neuroimmunol 1999 951-7 Full Text Bibliographic Links [Context Link]

190 Wen Y Scott S Liu Y et al Evidence that angiotensin II and lipoxygenase products activate c-Jun NH2-

terminal kinase Circ Res 1997 81651-655 Ovid Full Text Bibliographic Links [Context Link]

191 Arteel GE Briviba K Sies H Protection against peroxynitrite FEBS Lett 1999 445226-230 Full Text


192 Cuzzocrea S Zingarelli B OConnor M et al Effect of L-buthionine-(SR)-sulphoximine an inhibitor of gamma-

glutamylcysteine synthetase on peroxynitrite- and endotoxic shock-induced vascular failure Br J Pharmacol 1998


193 Cuzzocrea S Costantino G Zingarelli B et al The protective role of endogenous glutathione in carrageenan-

induced pleurisy in the rat Eur J Pharmacol 1999 372187-197 [Context Link]

194 Marshall KA Reist M Jenner P et al The neuronal toxicity of sulfite plus peroxynitrite is enhanced by

glutathione depletion Implications for Parkinsons disease Free Radic Biol Med 1999 27515-520 Full Text


195 Berendji D Kolb-Bachofen V Meyer KL et al Nitric oxide mediates intracytoplasmic and intranuclear zinc

release FEBS Lett 1997 40537-41 Full Text Bibliographic Links [Context Link]

196 Kroncke KD Kolb-Bachofen V Measurement of nitric oxide-mediated effects on zinc homeostasis and zinc

finger transcription factors Methods Enzymol 1999 301126-135 Bibliographic Links [Context Link]

197 Wink DA Laval J The Fpg protein a DNA repair enzyme is inhibited by the biomediator nitric oxide in vitro

and in vivo Carcinogenesis 1994 152125-2129 Bibliographic Links [Context Link]



198 Viner RI Williams TD Schoneich C Peroxynitrite Modification of Protein Thiols Oxidation Nitrosylation and

S-Glutathiolation of Functionally Important Cysteine Residue(s) in the Sarcoplasmic Reticulum Ca-ATPase


199 Lizasoain I Moro MA Knowles RG et al Nitric oxide and peroxynitrite exert distinct effects on

mitochondrial respiration which are differentially blocked by glutathione or glucose Biochem J 1996 314877-880


200 Szabo C Day BJ Salzman AL Evaluation of the relative contribution of nitric oxide and peroxynitrite to the

suppression of mitochondrial respiration in immunostimulated macrophages using a manganese mesoporphyrin

superoxide dismutase mimetic and peroxynitrite scavenger FEBS Lett 1996 38182-86 [Context Link]

201 Bolanos JP Heales SJ Land JM et al Effect of peroxynitrite on the mitochondrial respiratory chain

differential susceptibility of neurones and astrocytes in primary culture J Neurochem 1995 641965-1972


202 Cassina A Radi R Differential inhibitory action of nitric oxide and peroxynitrite on mitochondrial electron

transport Arch Biochem Biophys 1996 328309-316 Full Text Bibliographic Links [Context Link]

203 Radi R Rodriguez M Castro L et al Inhibition of mitochondrial electron transport by peroxynitrite Arch

Biochem Biophys 1994 30889-95 Full Text Bibliographic Links [Context Link]

204 Hausladen A Fridovich I Superoxide and peroxynitrite inactivate aconitases but nitric oxide does not J Biol

Chem 1994 26929405-29408 Bibliographic Links [Context Link]

205 Castro L Rodriguez M Radi R Aconitase is readily inactivated by peroxynitrite but not by its precursor

nitric oxide J Biol Chem 1994 26929409-29415 Bibliographic Links [Context Link]

206 Cheung PY Danial H Jong J et al Thiols protect the inhibition of myocardial aconitase by peroxynitrite

Arch Biochem Biophys 1998 350104-108 Full Text Bibliographic Links [Context Link]

207 Packer MA Porteous CM Murphy MP Superoxide production by mitochondria in the presence of nitric

oxide forms peroxynitrite Biochem Mol Biol Int 1996 40527-534 Bibliographic Links [Context Link]

208 MacMillan-Crow LA Crow JP Kerby JD et al Nitration and inactivation of manganese superoxide dismutase in

chronic rejection of human renal allografts Proc Natl Acad Sci U S A 1996 9311853-11858 Full Text


209 Szaboacute C OConnor M Salzman AL Endogenously produced peroxynitrite induces the oxidation of

mitochondrial and nuclear proteins in immunostimulated macrophages FEBS Lett 1997 409147-150 Full Text


210 Gadelha FR Thomson L Fagian MM et al Ca2+-independent permeabilization of the inner mitochondrial

membrane by peroxynitrite is mediated by membrane protein thiol cross-linking and lipid peroxidation Arch


211 Packer MA Scarlett JL Martin SW et al Induction of the mitochondrial permeability transition by

peroxynitrite Biochem Soc Trans 1997 25909-914 Bibliographic Links [Context Link]

212 Packer MA Murphy MP Peroxynitrite causes calcium efflux from mitochondria which is prevented by

cyclosporin A FEBS Lett 1994 345237-240 Full Text Bibliographic Links [Context Link]

213 Chakraborti T Das S Mondal M et al Oxidant mitochondria and calcium An overview Cell Signal 1999

1177-85 Full Text Bibliographic Links [Context Link]

214 Borutaite V Morkuniene R Brown GC Release of cytochrome c from heart mitochondria is induced by high

Ca2+ and peroxynitrite and is responsible for Ca(2+)-induced inhibition of substrate oxidation Biochim Biophys

Acta 1999 145341-48 [Context Link]

215 Heales SJ Bolanos JP Stewart VC et al Nitric oxide mitochondria and neurological disease Biochim

Biophys Acta 1999 1410215-228 Bibliographic Links [Context Link]




216 Ishida H Genka C Hirota Y et al Distinct roles of peroxynitrite and hydroxyl radical in triggering stunned

myocardium-like impairment of cardiac myocytes in vitro Mol Cell Biochem 1999 19831-38 Bibliographic Links

[Context Link]

217 Xie YW Kaminski PM Wolin MS Inhibition of rat cardiac muscle contraction and mitochondrial respiration by

endogenous peroxynitrite formation during posthypoxic reoxygenation Circ Res 1998 82891-897 Ovid Full Text


218 Szaboacute C Role of poly(ADP-ribose) synthetase activation in the suppression of cellular energetics in response

to nitric oxide and peroxynitrite Biochem Soc Trans 1997 25919-924 [Context Link]

219 Szaboacute C Zingarelli B OConnor M et al DNA strand breakage activation of poly (ADP-ribose) synthetase and

cellular energy depletion are involved in the cytotoxicity of macrophages and smooth muscle cells exposed to

peroxynitrite Proc Natl Acad Sci U S A 1996 931753-1758 Full Text Bibliographic Links [Context Link]

220 Szaboacute C Dawson VL Role of poly(ADP-ribose) synthetase in inflammation and ischaemia-reperfusion Trends

Pharmacol Sci 1998 19287-298 Full Text Bibliographic Links [Context Link]

221 Szaboacute C Ohshima H DNA damage induced by peroxynitrite subsequent biological effects Nitric Oxide 1997


222 Shimabukuro M Ohneda M Lee Y et al Role of nitric oxide in obesity-induced beta cell disease J Clin

Invest 1997 100290-295 Bibliographic Links [Context Link]

223 Szaboacute C Wong H Bauer P et al Regulation of components of the inflamatory response by 5-iodo-6-amino-12-

benzopyrone an inhibitor of poly(ADP-ribose) synthetase and pleiotropic modifier of cellular signal pathways Int J

Oncol 19971093-1101 [Context Link]

224 Thiemermann C Bowes J Myint FP et al Inhibition of the activity of poly(ADP ribose) synthetase reduces

ischemia-reperfusion injury in the heart and skeletal muscle Proc Natl Acad Sci U S A 1997 94679-683 Full Text


225 Zingarelli B Cuzzocrea S Zsengeller Z et al Protection against myocardial ischemia and reperfusion injury

by 3-aminobenzamide an inhibitor of poly (ADP-ribose) synthetase Cardiovasc Res 1997 36205-215 Full Text


226 Brune B von Knethen A Sandau KB Nitric oxide and its role in apoptosis Eur J Pharmacol 1998 351261-272


227 Albina JE Cui S Mateo RB et al Nitric oxide-mediated apoptosis in murine peritoneal macrophages J

Immunol 1993 1505080-5085 Bibliographic Links [Context Link]

228 Fehsel K Kroncke KD Meyer KL et al Nitric oxide induces apoptosis in mouse thymocytes J Immunol 1995


229 Pinsky DJ Aji W Szabolcs M et al Nitric oxide triggers programmed cell death (apoptosis) of adult rat

ventricular myocytes in culture Am J Physiol 1999 277H1189-H1199 Bibliographic Links [Context Link]

230 Lopez-Collazo E Mateo J M iras-Portugal MT et al Requirement of nitric oxide and calcium mobilization for

the induction of apoptosis in adrenal vascular endothelial cells FEBS Lett 1997 413124-128 Full Text


231 Kaneto H Fujii J Seo HG et al Apoptotic cell death triggered by nitric oxide in pancreatic beta-cells

Diabetes 1995 44733-738 Bibliographic Links [Context Link]

232 Messmer UK Ankarcrona M Nicotera P et al p53 expression in nitric oxide-induced apoptosis FEBS Lett

1994 35523-26 [Context Link]



233 Messmer UK Brune B Nitric oxide-induced apoptosis p53-dependent and p53-independent signalling

pathways Biochem J 1996 319299-305 Bibliographic Links [Context Link]

234 Ambs S Hussain SP Harris CC Interactive effects of nitric oxide and the p53 tumor suppressor gene in

carcinogenesis and tumor progression FASEB J 1997 11443-448 Bibliographic Links [Context Link]

235 Glockzin S von Knethen A Scheffner M et al Activation of the cell death program by nitric oxide involves

inhibition of the proteasome J Biol Chem 1999 27419581-19586 Bibliographic Links [Context Link]

236 Yabuki M Kariya S Inai Y et al Molecular mechanisms of apoptosis in HL-60 cells induced by a nitric oxide-

releasing compound [published erratum appears in Free Radic Res 1997 27659] Free Radic Res 1997 27325-335


237 Sandau K Pfeilschifter J Brune B Nitrosative and oxidative stress induced heme oxygenase-1 accumulation

in rat mesangial cells Eur J Pharmacol 1998 34277-84 Full Text Bibliographic Links [Context Link]

238 Raghuram N Fortenberry JD Owens ML et al Effects of exogenous nitric oxide and hyperoxia on lung

fibroblast viability and DNA fragmentation Biochem Biophys Res Commun 1999 262685-691 Full Text


239 Virag L Scott GS Cuzzocrea S et al Peroxynitrite-induced thymocyte apoptosis the role of caspases and

poly (ADP-ribose) synthetase (PARS) activation Immunology 1998 94345-355 [Context Link]

240 Lin KT Xue JY Lin MC et al Peroxynitrite induces apoptosis of HL-60 cells by activation of a caspase-3 family

protease Am J Physiol 1998 274C855-C860 Bibliographic Links [Context Link]

241 Yabuki M Kariya S Ishisaka R et al Resistance to nitric oxide-mediated apoptosis in HL-60 variant cells is

associated with increased activities of CuZn-superoxide dismutase and catalase Free Radic Biol Med 1999 26325-


242 Keller JN Kindy MS Holtsberg FW et al M itochondrial manganese superoxide dismutase prevents neural

apoptosis and reduces ischemic brain injury suppression of peroxynitrite production lipid peroxidation and

mitochondrial dysfunction J Neurosci 1998 18687-697 Bibliographic Links [Context Link]

243 Estevez AG Spear N Manuel SM et al Nitric oxide and superoxide contribute to motor neuron apoptosis

induced by trophic factor deprivation J Neurosci 1998 18923-931 Bibliographic Links [Context Link]

244 Kurrer MO Pakala SV Hanson HL et al Beta cell apoptosis in T cell-mediated autoimmune diabetes Proc

Natl Acad Sci U S A 1997 94213-218 [Context Link]

245 Delaney CA Tyrberg B Bouwens L et al Sensitivity of human pancreatic islets to peroxynitrite-induced cell

dysfunction and death FEBS Lett 1996 394300-306 Full Text Bibliographic Links [Context Link]

246 Suarez-Pinzon WL Szabo C Rabinovitch A Development of autoimmune diabetes in NOD mice is associated

with the formation of peroxynitrite in pancreatic islet betacells Diabetes 1997 46907-911 Bibliographic Links

[Context Link]

247 Fortenberry JD Owens ML Brown MR et al Exogenous nitric oxide enhances neutrophil cell death and DNA

fragmentation Am J Respir Cell Mol Biol 1998 18421-428 Bibliographic Links [Context Link]

248 Bosca L Hortelano S Mechanisms of nitric oxide-dependent apoptosis Involvement of mitochondrial

mediators Cell Signal 1999 11239-244 Full Text Bibliographic Links [Context Link]

249 Koglin J Granville DJ Glysing-Jensen T et al Attenuated acute cardiac rejection in NOS2 -- recipients

correlates with reduced apoptosis Circulation 1999 99836-842 Ovid Full Text Bibliographic Links [Context

Link]

250 Szabolcs MJ Ravalli S M inanov O et al Apoptosis and increased expression of inducible nitric oxide synthase

in human allograft rejection Transplant 1998 65804-812 [Context Link]



251 Sandoval M Zhang XJ Liu X et al Peroxynitrite-induced apoptosis in T84 and RAW 2647 cells Attenuation

by L-ascorbic acid Free Radic Biol Med 1997 22489-495 Full Text Bibliographic Links [Context Link]

252 Bolanos JP Almeida A Stewart V et al Nitric oxide-mediated mitochondrial damage in the brain mechanisms

and implications for neurodegenerative diseases J Neurochem 1997 682227-2240 Buy Now Bibliographic Links

[Context Link]

253 Bonfoco E Krainc D Ankarcrona M et al Apoptosis and necrosis Two distinct events induced respectively

by mild and intense insults with N-methyl-D-aspartate or nitric oxidesuperoxide in cortical cell cultures Proc

Natl Acad Sci U S A 1995 927162-7166 Full Text Bibliographic Links [Context Link]

254 Leist M Single B Naumann H et al Inhibition of mitochondrial ATP generation by nitric oxide switches

apoptosis to necrosis Exp Cell Res 1999 249396-403 Full Text Bibliographic Links [Context Link]

255 Genaro AM Hortelano S Alvarez A et al Splenic B lymphocyte programmed cell death is prevented by nitric

oxide release through mechanisms involving sustained Bcl-2 levels J Clin Invest 1995 951884-1890 [Context Link]

256 Kim YM Chung HT Kim SS et al Nitric oxide protects PC12 cells from serum deprivation-induced apoptosis

by cGMP-dependent inhibition of caspase signaling J Neurosci 1999 196740-6747 Bibliographic Links [Context

Link]

257 Haendeler J Weiland U Zeiher AM et al Effects of redox-related congeners of NO on apoptosis and

caspase-3 activity Nitric Oxide 1997 1282-293 Full Text Bibliographic Links [Context Link]

258 Li J Bombeck CA Yang S et al Nitric oxide suppresses apoptosis via interrupting caspase activation and

mitochondrial dysfunction in cultured hepatocytes J Biol Chem 1999 27417325-17333 Bibliographic Links

[Context Link]

259 Mohr S Zech B Lapetina EG et al Inhibition of caspase-3 by S-nitrosation and oxidation caused by nitric

oxide Biochem Biophys Res Commun 1997 238387-391 [Context Link]

260 Stefanelli C Pignatti C Tantini B et al Nitric oxide can function as either a killer molecule or an

antiapoptotic effector in cardiomyocytes Biochim Biophys Acta 1999 1450406-413 Bibliographic Links [Context

Link]

261 Howlett CE Hutchison JS Veinot JP et al Inhaled nitric oxide protects against hyperoxia-induced apoptosis

in rat lungs Am J Physiol 1999 277L596-L605 Bibliographic Links [Context Link]

262 Furuke K Burd PR Horvath-Arcidiacono JA et al Human NK cells express endothelial nitric oxide synthase

and nitric oxide protects them from activation-induced cell death by regulating expression of TNF-alpha J

Immunol 1999 1631473-1480 [Context Link]

263 Foresti R Sarathchandra P Clark JE et al Peroxynitrite induces haem oxygenase-1 in vascular endothelial

cells A link to apoptosis Biochem J 1999 339729-736 Bibliographic Links [Context Link]

264 Madesh M Ramachandran A Balasubramanian KA Nitric oxide prevents anoxia-induced apoptosis in colonic

HT29 cells Arch Biochem Biophys 1999 366240-248 [Context Link]

265 Ischiropoulos H Biological tyrosine nitration A pathophysiological function of nitric oxide and reactive

oxygen species Arch Biochem Biophys 1998 3561-11 Full Text Bibliographic Links [Context Link]

266 Eiserich JP Cross CE Jones AD et al Formation of nitrating and chlorinating species by reaction of nitrite

with hypochlorous acid A novel mechanism for nitric oxide-mediated protein modification J Biol Chem 1996


267 van der Vliet A Eiserich JP Halliwell B et al Formation of reactive nitrogen species during peroxidase-

catalyzed oxidation of nitrite A potential additional mechanism of nitric oxide- dependent toxicity J Biol Chem


268 Beckman JS Carson M Smith CD et al ALS SOD and peroxynitrite Nature 1993 364584 Bibliographic Links

[Context Link]



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269 Boota A Zar H Kim YM et al IL-1 beta stimulates superoxide and delayed peroxynitrite production by

pulmonary vascular smooth muscle cells Am J Physiol 1996 271L932-L938 Bibliographic Links [Context Link]

270 Crow JP Ye YZ Strong M et al Superoxide dismutase catalyzes nitration of tyrosines by peroxynitrite in the

rod and head domains of neurofilament-L J Neurochem 1997 691945-1953 Buy Now Bibliographic Links

[Context Link]

271 Crow JP Sampson JB Zhuang Y et al Decreased zinc affinity of amyotrophic lateral sclerosis-associated

superoxide dismutase mutants leads to enhanced catalysis of tyrosine nitration by peroxynitrite J Neurochem

1997 691936-1944 Buy Now Bibliographic Links [Context Link]

272 van der Vliet A Eiserich JP Shigenaga MK et al Reactive nitrogen species and tyrosine nitration in the

respiratory tract Epiphenomena or a pathobiologic mechanism of disease Am J Respir Crit Care Med 1999 1601-9


273 Ara J Przedborski S Naini AB et al Inactivation of tyrosine hydroxylase by nitration following exposure to

peroxynitrite and 1-methyl-4-phenyl-1236-tetrahydropyridine (MPTP) Proc Natl Acad Sci U S A 1998 957659-


274 Gow AJ Duran D Malcolm S et al Effects of peroxynitrite-induced protein modifications on tyrosine

phosphorylation and degradation FEBS Lett 1996 38563-66 Full Text Bibliographic Links [Context Link]

275 Kong SK Yim MB Stadtman ER et al Peroxynitrite disables the tyrosine phosphorylation regulatory

mechanism Lymphocyte-specific tyrosine kinase fails to phosphorylate nitrated cdc2(6-20)NH2 peptide Proc Natl

Acad Sci U S A 1996 933377-3382 Full Text Bibliographic Links [Context Link]

276 Southan GJ Szabo C Selective pharmacological inhibition of distinct nitric oxide synthase isoforms Biochem


277 Cobb JP Hotchkiss RS Swanson PE et al Inducible nitric oxide synthase (iNOS) gene deficiency increases

the mortality of sepsis in mice Surgery 1999 126438-442 Full Text Bibliographic Links [Context Link]

278 Karupiah G Xie QW Buller RM et al Inhibition of viral replication by interferon-gamma-induced nitric oxide

synthase Science 1993 2611445-1448 Full Text Bibliographic Links [Context Link]

Key Words cell signaling cytotoxicity dinitrogen trioxide nitric oxide nitration nitrosation nitrosothiols

oxidation peroxynitrite superoxide radical

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least considered from our viewpoint represent the critical basis to the understanding of the roles played by NO

in both the healthy and the aggressed organism

Figure 1 Physiologic chemistry of nitric oxide (NO) separation between direct and indirect effects

BIOLOGICAL CHEMISTRY OF NO INSIGHT INTO REGULATORY AND CYTOTOXIC ACTIONS

Overview of NO Synthases

NO is synthesized from the guanidino group of L-arginine by a family of enzymes termed NO synthases (NOS)

from which three isoforms have been described and cloned All three isoforms use nicotinamide

diphosphonucleotide (NADPH) and molecular oxygen as cosubstrates and all contain the following prosthetic

groups flavin-adenine mononucleotide flavin mononucleotide tetrahydrobiopterin zinc and a heme complex

ironprotoporphyrin IX (8) Classically the NOS isoforms have been subdivided into a constitutive (cNOS) and an

inducible nitric oxide synthase (iNOS) activity (1) a terminology which tends to become obsolete since the

observation that the constitutive isoforms may be induced in some circumstances and that inducible NOS may

be constitutively expressed in some cells (9) A further classification denotes the cell type where the different

isoforms were first described and their dependence on a Ca2+ transient (gt~100 nM) for full enzyme activity (1)

Thus cNOS encompasses the calcium-dependent isoforms found in endothelial (eNOS or NOS 3) and neuronal

(nNOS or NOS 1) cells producing small (picomolar) amounts of NO for short periods In contrast the macrophage-

type iNOS expressed on stimulation by various proinflammatory signals is maintained in a constant activated state

independently from calcium and thus produces high (nM) amounts of NO for extended periods of time (2)

Accordingly the direct effects of NO are essentially determined by the activity of cNOS isoforms whereas

indirect effects become relevant in conditions of iNOS expression However this assumption is not always true

since significant cytotoxicity resulting from indirect effects of NO may be observed in absence of iNOS

expression as in a wide range of neurologic diseases and in the early phase of ischemia-reperfusion injury where

NO is provided respectively by nNOS and eNOS Conversely iNOS expression is not always correlated with tissue

injury the best example being pregnancy during which iNOS is expressed in the placenta and fetal organs

producing substantial amounts of NO without apparent toxic consequences (10)

Direct Effects of NO (Table 1)

Table 1 Direct effects of nitric oxide (NO)

Reactions of NO With Metals The direct interactions of NO with transition metals leads to three types of

reactions including a) the formation of stable nitrosyl complexes via covalent reactions between NO and metal

ions b) redox reactions between NO and metal ions and c) NO binding to iron-sulfur clusters in proteins (6)

Formation of stable nitrosyl complexes mainly occurs with ferrous iron in heme-containing proteins resulting in a

displacement of the iron out of the plane of the porphyrinic ring (11) This conformational change may result in

totally opposite effects (activation or inhibition) depending on the affected protein

Guanylyl Cyclase The best characterized reaction between NO and a heme protein is the NO-dependent

activation of soluble guanylyl (formerly also termed guanylate) cyclase (sGC) leading to its translocation to the






































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Biology of nitric oxide signaling

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Transcript of Biology of nitric oxide signaling