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• W2094764360 abstract "We report here that, like nonheme iron, protein-bound intracellular heme iron is also a target for destruction by endogenously produced nitric oxide (●NO). In isolated rat hepatocytes ●NO synthesis results in substantial (approximately 60%) and comparable loss of catalase and cytochrome P450 as well as total microsomal heme, and decreased heme synthetic (δ-aminolevulinate synthetase and ferrochelatase) and increased degradative (heme oxygenase) enzymatic activities. The effect is reversible, and intact cytochrome P450 apoproteins are still present, as judged by heme reconstitution of isolated microsomes. The effects on δ-aminolevulinate synthetase and heme oxygenase are likely to be secondary to heme liberation, while the effects on ferrochelatase appear to be a direct effect of ●NO, perhaps destruction of its nonheme iron-sulfur center. We report here that, like nonheme iron, protein-bound intracellular heme iron is also a target for destruction by endogenously produced nitric oxide (●NO). In isolated rat hepatocytes ●NO synthesis results in substantial (approximately 60%) and comparable loss of catalase and cytochrome P450 as well as total microsomal heme, and decreased heme synthetic (δ-aminolevulinate synthetase and ferrochelatase) and increased degradative (heme oxygenase) enzymatic activities. The effect is reversible, and intact cytochrome P450 apoproteins are still present, as judged by heme reconstitution of isolated microsomes. The effects on δ-aminolevulinate synthetase and heme oxygenase are likely to be secondary to heme liberation, while the effects on ferrochelatase appear to be a direct effect of ●NO, perhaps destruction of its nonheme iron-sulfur center. Nitric oxide (●NO) is produced by specific mammalian enzymes either in small quantities as a neural or vascular messenger or in large quantities by certain cells of the immune system as an effector where it is cytostatic/cytotoxic to many pathogenic organisms and also to infected or transformed host cells(1Nathan C. FASEB J. 1992; 6: 3051-3064Crossref PubMed Scopus (4128) Google Scholar, 2Hibbs Jr., J.B. Taintor R.R. Vavrin Z. Granger D.L. Drapier J.C. Amber I.J. Lancaster Jr., J.R. Moncada S. Higgs E.A. Nitric Oxide from L-Arginine: A Bioregulatory System. Elsevier Science Publishers B.V., Amsterdam1990: 189-223Google Scholar). Intracellular iron is a major target of ●NO as an immune effector, and previous studies have described loss of nonheme iron-containing enzyme activities(1Nathan C. FASEB J. 1992; 6: 3051-3064Crossref PubMed Scopus (4128) Google Scholar, 2Hibbs Jr., J.B. Taintor R.R. Vavrin Z. Granger D.L. Drapier J.C. Amber I.J. Lancaster Jr., J.R. Moncada S. Higgs E.A. Nitric Oxide from L-Arginine: A Bioregulatory System. Elsevier Science Publishers B.V., Amsterdam1990: 189-223Google Scholar). Although heme iron is also a well established target for exogenous ●NO(3Henry Y. Lepoivre M. Drapier J.C. Ducrocq C. Boucher J.L. Guissani A. FASEB J. 1993; 7: 1124-1134Crossref PubMed Scopus (352) Google Scholar), few studies have demonstrated deleterious effects of endogenous ●NO synthesis on intracellular heme-containing enzymes. Recently it has been found that rat hepatic ●NO synthesis results in a decrease in both activity and levels of cytochrome P450 (CYP)( 1The abbreviations used are: CYPcytochrome P450CMEa cytokine mixture (tumor necrosis factor-α, interferon-α, interleukin-1β) plus endotoxin/lipopolysaccharideHOheme oxygenaseNMMANG-monomethyl-L-arginineNOxnitrite plus nitratePBSphosphate-buffered salineP420cytochrome P420P450cytochrome P450SNAPS-nitroso-N-acetylpenicillamine. )(4Khatsenko O.G. Gross S.S. Rifkind A.B. Vane J.R. Proc. Natl. Acad. Sci. U. S. A. 1993; 90: 11147-11151Crossref PubMed Scopus (284) Google Scholar, 5Stadler J. Trockfeld J. Schmalix W.A. Brill T. Siewert J.R. Greim H. Doehmer J. Proc. Natl. Acad. Sci. U. S. A. 1994; 91: 3559-3563Crossref PubMed Scopus (213) Google Scholar). Understanding the mechanism by which endogenous ●NO inhibits heme-containing proteins is likely to explain such important phenomena as decreased drug tolerance in septic patients(6Kraemer M.J. Furukawa C.T. Koup J.R. Shapiro G.G. Pierson W.E. Bierman C.W. Pediatrics. 1982; 69: 476-480PubMed Google Scholar). We describe here one basis for this phenomenon, which involves ●NO-induced intracellular heme loss and increased heme degradation. cytochrome P450 a cytokine mixture (tumor necrosis factor-α, interferon-α, interleukin-1β) plus endotoxin/lipopolysaccharide heme oxygenase NG-monomethyl-L-arginine nitrite plus nitrate phosphate-buffered saline cytochrome P420 cytochrome P450 S-nitroso-N-acetylpenicillamine. Williams media E, trypan blue, insulin, penicillin, streptomycin, L-glutamine, and HEPES were purchased from Life Technologies, Inc. Calf serum was purchased from Hyclone Laboratories (Logan, UT). Collagenase was purchased from Boehringer Mannheim. S-Nitroso-N-acetylpenicillamine (SNAP) was synthesized as described previously(7Field L. Dilts R.V. Ravichandran R. Lenhert P.G. Carnahan G.E. J. Chem. Soc. Chem. Commun. 1978; : 249-250Crossref Google Scholar), stored frozen as a solid in the dark, and routinely checked for stoichiometric S-nitrosothiol content by the method of Saville(8Saville B. Analyst. 1958; 83: 670-672Crossref Google Scholar). Other chemicals were obtained from Sigma unless otherwise stated. Purified hepatocytes were isolated and treated with a cytokine mixture (tumor necrosis factor-α (Genzyme), interferon-α (Amgen), interleukin-1β (Cistron)) plus endotoxin/lipopolysaccharide (Escherichia coli 0111:B4, Sigma) (CME) with or without NG-monomethyl-L-arginine (NMMA) for 24 h as described previously(9Stadler J. Bergonia H.A. Di Silvio M. Sweetland M.A. Billiar T.R. Simmons R.L. Lancaster Jr., J.R. Arch. Biochem. Biophys. 1993; 302: 4-11Crossref PubMed Scopus (114) Google Scholar). Cells were also exposed for 9 h to 1 mM SNAP in medium. Cell death (measured by crystal violet staining) resulting from the various treatments was found to be minimal. Hepatocytes (1 × 107 cells) were suspended in 750 μl of PBS and homogenized on ice for 2 min by using a glass tissue homogenizer with a Teflon pestle. The solution was centrifuged at maximum speed (14,000 rpm) for 10 min at 4°C in an Eppendorf microcentrifuge. The supernatant was designated as enzyme solution for catalase assay. Catalase activity was measured using a Clark type oxygen electrode (Yellow Springs Instruments Co.) as described(10Del Maestro R.F. McDonald W. Greenwald R.A. CRC Handbook of Methods for Oxygen Radical Research. CRC Press, Inc., Boca Raton, FL1985: 291-296Google Scholar). The reaction mixture in a final volume of 1.5 ml of degassed PBS contained 20 μl of the enzyme solution and 50 μl of 400 mM H2O2 in PBS. For isolation of microsomes, crude cytosol (11Kim Y.M. Lancaster Jr., J.R. FEBS Lett. 1993; 332: 255-259Crossref PubMed Scopus (29) Google Scholar) was spun at 100,000 × g for 90 min to pellet the microsomes. Spectra and quantitation of the reduced versus reduced plus CO complex of CYP were as described(12Estabrook R.W. Werringloer J. Methods Enzymol. 1978; 52: 212-220Crossref PubMed Scopus (302) Google Scholar). Total extractable heme was quantified according to a previously described method(13Berry E.A. Trumpower B.L. Anal. Biochem. 1987; 161: 1-15Crossref PubMed Scopus (726) Google Scholar). Microsomes (10 μM total heme) were exposed to dissolved ●NO (88 μM) anaerobically for varying times at room temperature after which the ●NO was removed by gassing with argon, and total CYP heme was assayed as described above. For heme reconstitution of P450, each microsomal fraction (control, CME (24 h), CME + NMMA (24 h), and SNAP (12 h)) was divided between two dialyzing tubes. One tube was dialyzed aerobically for 6 h at 4°C against phosphate buffer (0.1 M, pH 6.8), while the other was dialyzed aerobically against the same buffer but contained 50 μM heme (hematin reduced to heme by an equivalent amount of sodium dithionite in a small volume). All samples were dialyzed further against phosphate buffer for 24 h to remove excess heme, and CYP was determined as described above. Total iron was determined using a colorimetric micromethod after acid-permanganate treatment(14Fish W.W. Methods Enzymol. 1988; 158: 357-364Crossref PubMed Scopus (522) Google Scholar). Nonheme iron is expressed as the difference between the total and heme iron. δ-Aminolevulinate synthetase, heme oxygenase (HO), and ferrochelatase activities were assayed as described(15Cable E.E. Healey J.F. Greene Y. Evans C.O. Bonkovsky H.L. Biochim. Biophys. Acta. 1991; 1080: 245-251Crossref PubMed Scopus (22) Google Scholar, 16Bonkovsky H.L. Healey J.F. Pohl J. Eur. J. Biochem. 1990; 189: 155-166Crossref PubMed Scopus (41) Google Scholar, 17Taketani S. Tokunaga R. J. Biol. Chem. 1981; 256: 12748-12753Abstract Full Text PDF PubMed Google Scholar). Total RNA was extracted from the cultured hepatocytes, electrophoresed, and blotted as described by Geller et al.(18Geller D.A. Nussler A.K. Di Silvio M. Lowenstein C.J. Shapiro R.A. Wang S.C. Simmons R.L. Billiar T.R. Proc. Natl. Acad. Sci. U. S. A. 1993; 90: 522-526Crossref PubMed Scopus (634) Google Scholar). The probe to inducible nitric oxide synthase used was a 2.7-kilobase cDNA obtained by NotI digestion from a mouse macrophage cDNA clone(18Geller D.A. Nussler A.K. Di Silvio M. Lowenstein C.J. Shapiro R.A. Wang S.C. Simmons R.L. Billiar T.R. Proc. Natl. Acad. Sci. U. S. A. 1993; 90: 522-526Crossref PubMed Scopus (634) Google Scholar). The HO probe used was a 1.4-kilobase cDNA obtained by EcoRI digestion from a human macrophage (U937 histiolytic lymphoma) cDNA clone(19Yoshida T. Biro P. Cohen T. Müller R.M. Shibahara S. Eur. J. Biochem. 1988; 171: 457-461Crossref PubMed Scopus (267) Google Scholar). Radioactive membranes were quantified with storage phosphor screens (PhosphorImager, Molecular Dynamics), and the relative amount of mRNA is presented as the ratio of mRNA to 18 S RNA. The appearance of total medium NOx (NO2−+ NO3−) was measured as described previously(9Stadler J. Bergonia H.A. Di Silvio M. Sweetland M.A. Billiar T.R. Simmons R.L. Lancaster Jr., J.R. Arch. Biochem. Biophys. 1993; 302: 4-11Crossref PubMed Scopus (114) Google Scholar). Protein concentration was measured by Lowry protein assay kit (P5656, Sigma). Results represent means ± S.D. from a minimum of three experiments. Significance between groups was determined using the Student's unpaired t test. Catalase is a heme-containing enzyme that catalyzes the dismutation of H2O2 to O2 and H2O. As shown in Fig. 1A, treatment of hepatocytes with CME (which we have shown previously to induce substantial ●NO synthesis(9Stadler J. Bergonia H.A. Di Silvio M. Sweetland M.A. Billiar T.R. Simmons R.L. Lancaster Jr., J.R. Arch. Biochem. Biophys. 1993; 302: 4-11Crossref PubMed Scopus (114) Google Scholar)) results in a decrease followed by gradual recovery of catalase activity. The minimum activity (65% loss) occurred at approximately the same time as the maximum rate of ●NO synthesis, as we have shown previously(20Nussler A.K. Geller D.A. Sweetland M.A. Di Silvio M. Billiar T.R. Madariaga J.B. Simmons R.L. Lancaster Jr., J.R. Biochem. Biophys. Res. Commun. 1993; 194: 826-835Crossref PubMed Scopus (87) Google Scholar). Inhibition of ●NO synthesis by NMMA results in oblation of catalase activity loss, demonstrating that it is due to ●NO production. This result raises the possibility that inhibition of catalase may be a previously unrecognized mechanism of ●NO-induced potentiation of oxidative injury(21Grisham M.B. Reactive Metabolites of Oxygen and Nitrogen in Biology and Medicine. R. G. Landes Co., Austin, TX1992Google Scholar). The CYPs are heme-containing enzymes that catalyze the metabolism of a variety of endogenous and exogenous compounds. We chose this class of enzymes for further studies on the effects of ●NO because they represent the major heme pool in hepatocytes(22Bonkovsky H.L. Zakim D. Boyer T.D. Hepatology. A Textbook of Liver Disease. W. B. Saunders Co., Philadelphia1982: 351-393Google Scholar), and inactivation can be monitored by the reduced versus reduced + CO difference spectrum of the microsomal fraction(23Guengerich F.P. FASEB J. 1992; 6: 667-668Crossref PubMed Scopus (50) Google Scholar). Fig. 1B shows the effects of endogenous and exogenous ●NO on microsomal CYP heme and total extractable microsomal heme (13Berry E.A. Trumpower B.L. Anal. Biochem. 1987; 161: 1-15Crossref PubMed Scopus (726) Google Scholar) in cultured rat hepatocytes. Exogenous ●NO exposure was accomplished by using SNAP, an ●NO donor. Compared with control cells there is an approximately 60% decrease in basal (uninduced) CYP heme induced by either endogenous or exogenous ●NO, as reported previously for inducible CYP heme(4Khatsenko O.G. Gross S.S. Rifkind A.B. Vane J.R. Proc. Natl. Acad. Sci. U. S. A. 1993; 90: 11147-11151Crossref PubMed Scopus (284) Google Scholar, 5Stadler J. Trockfeld J. Schmalix W.A. Brill T. Siewert J.R. Greim H. Doehmer J. Proc. Natl. Acad. Sci. U. S. A. 1994; 91: 3559-3563Crossref PubMed Scopus (213) Google Scholar). CYP heme loss is prevented by inhibition of ●NO synthesis (NMMA). The parent compound of SNAP (N-acetylpenicillamine, not containing a nitrosyl group) had no effect (data not shown); that was also true for all other studies below with SNAP. In order to determine whether this effect is due to prevention by ●NO of CO binding to heme (thus masking the appearance of the 450 nm peak(4Khatsenko O.G. Gross S.S. Rifkind A.B. Vane J.R. Proc. Natl. Acad. Sci. U. S. A. 1993; 90: 11147-11151Crossref PubMed Scopus (284) Google Scholar)) or instead loss of CYP protein and/or heme, we assayed total extractable microsomal heme. Fig. 1B shows that both endogenous and exogenous ●NO cause a loss of total microsomal heme that is quantitatively indistinguishable from CYP heme loss. Having established that the effect of ●NO is due to decreased holocytochrome P450 (and not prevention of CO binding), we next determined whether this effect is due to a decrease in CYP protein expression (as reported by Stadler et al.(5Stadler J. Trockfeld J. Schmalix W.A. Brill T. Siewert J.R. Greim H. Doehmer J. Proc. Natl. Acad. Sci. U. S. A. 1994; 91: 3559-3563Crossref PubMed Scopus (213) Google Scholar) for inducible CYP) or to loss of enzyme-bound heme. We first determined if exposure of microsomes from untreated hepatocytes to ●NO induces loss of heme. As shown in Fig. 1C, exposure of microsomes from untreated hepatocytes (I) to ●NO for 20 min (II) results in partial conversion of P450 into P420, indicative of sulfur to nitrogen exchange of proximal axial heme ligand (23Guengerich F.P. FASEB J. 1992; 6: 667-668Crossref PubMed Scopus (50) Google Scholar). From comparison with the spectrum of free heme (IV), after a further 40-min exposure (III) it can be concluded that a substantial portion of CYP heme is fully detached from its normal binding in the proteins, as judged by the appearance of the peak at 405 nm(24Marden M.C. Hazard E.S. Leclerc L. Gibson Q.H. Biochemistry. 1989; 28: 4422-4426Crossref PubMed Scopus (33) Google Scholar). Therefore it appears that NO exposure induces P450 to P420 conversion followed by release of heme from CYP. In order to determine whether a decrease in CYP is due to decreased CYP protein or loss of heme, we determined whether CYP apoprotein is present after loss of heme. We determined this by isolating microsomes from ●NO-synthesizing hepatocytes (or from hepatocytes treated with SNAP), dialyzing the preparations versus heme, and then measuring the reduced versus reduced plus CO spectrum of the preparations to determine whether heme had reinserted into apocytochrome P450 (Fig. 1D). This method has been used successfully for reconstitution of several cytochrome P450s subsequent to several methods of inducing heme loss/destruction, including P450cam(25Yu C-A. Gunsalus I.C. J. Biol. Chem. 1974; 249: 107-110Abstract Full Text PDF PubMed Google Scholar), P450SCC(26Pikuleva I.A. Lapko A.G. Chashchin V.L. J. Biol. Chem. 1992; 267: 1438-1442Abstract Full Text PDF PubMed Google Scholar), as well as the system studied here, rat hepatic microsomal cytochrome P450(27Bonkovsky H.L. Sinclair J.F. Healey J.F. Sinclair P.R. Smith E.L. Biochem. J. 1984; 222: 453-462Crossref PubMed Scopus (17) Google Scholar, 28Bornheim L.M. Parish D.W. Smith K.M. Litman D.A. Correia M.A. Arch. Biochem. Biophys. 1986; 246: 63-74Crossref PubMed Scopus (11) Google Scholar). Numerous studies have documented that the characteristic peak at 450 nm (for which these enzymes are named) is due to proximal cysteine ligation to the heme and that conversion to nitrogenous proximal heme ligation results in a shift in the peak to 420 nm with consequent loss of activity(23Guengerich F.P. FASEB J. 1992; 6: 667-668Crossref PubMed Scopus (50) Google Scholar). As shown in spectra I, dialysis versus heme of microsomes from control hepatocytes did not result in appreciable effects on the total CYP heme and resulted in no appreciable increase in either P420 or P450 heme absorption, as was also true for hepatocytes treated with the cytokine mixture plus NMMA (III). As shown in II, however, the substantial loss of CYP in microsomes from ●NO-synthesizing hepatocytes was restored by dialysis versus heme. Spectra IV show an effect with SNAP-treated cells that is similar to ●NO-producing cells, demonstrating that either endogenous or exogenous ●NO induces comparable effects. These results demonstrate that, in contrast to CYP induced by xenobiotic exposure (5Stadler J. Trockfeld J. Schmalix W.A. Brill T. Siewert J.R. Greim H. Doehmer J. Proc. Natl. Acad. Sci. U. S. A. 1994; 91: 3559-3563Crossref PubMed Scopus (213) Google Scholar), the virtually exclusive effect of ●NO on basal CYP is loss of the heme prosthetic group with no appreciable decrease in CYP protein. In addition, the CYP apoproteins are left in a relatively native conformation since P450 (not P420) is reconstituted by heme. We note that while observation of the feature at 450 nm demonstrates that heme has indeed reinserted into the apoproteins (thus showing that CYP apoproteins are present), we have not attempted to determine whether dialysis versus heme results in reconstitution of any specific P450 activity because different CYP isoforms may be differently affected by ●NO (as described below). We next determined whether intracellular heme levels in ●NO-producing hepatocytes change as a result of liberation from CYP, which is known to be the major heme pool in these cells(22Bonkovsky H.L. Zakim D. Boyer T.D. Hepatology. A Textbook of Liver Disease. W. B. Saunders Co., Philadelphia1982: 351-393Google Scholar). Previous studies have demonstrated ●NO-induced loss of total cellular iron from cells (including hepatocytes(29Billiar T.R. Curran R.D. Stuehr D.J. Ferrari F.K. Simmons R.L. Surgery. 1989; 106: 364-371PubMed Google Scholar)), although no differentiation of heme versus nonheme iron has yet been made(1Nathan C. FASEB J. 1992; 6: 3051-3064Crossref PubMed Scopus (4128) Google Scholar, 2Hibbs Jr., J.B. Taintor R.R. Vavrin Z. Granger D.L. Drapier J.C. Amber I.J. Lancaster Jr., J.R. Moncada S. Higgs E.A. Nitric Oxide from L-Arginine: A Bioregulatory System. Elsevier Science Publishers B.V., Amsterdam1990: 189-223Google Scholar). As shown in Fig. 2A, there is a selective loss of whole cell total extractable heme iron upon induction of ●NO synthesis with CME, which is prevented by NMMA. Similar loss occurs with SNAP-treated cells. No significant change in total cellular nonheme iron occurs (Fig. 2B), although the total amount of nonheme iron is much more than heme iron. Similar relative changes in heme also occur in the microsomal and cytosolic subcellular fractions. Interestingly, there is a relatively modest but detectable increase in nonheme iron in the cytosolic fraction, which may represent increased iron storage as ferritin(30Leibold E.A. Guo B. Annu. Rev. Nutr. 1992; 12: 345-368Crossref PubMed Scopus (118) Google Scholar). In hepatocytes, free heme is known to up-regulate its own degradation (by transcriptionally regulated increase of HO) and down-regulate endogenous synthesis (by decrease of mRNA stability and mitochondrial import of δ-aminolevulinate synthetase(22Bonkovsky H.L. Zakim D. Boyer T.D. Hepatology. A Textbook of Liver Disease. W. B. Saunders Co., Philadelphia1982: 351-393Google Scholar)). As shown in Fig. 3A, induction of ●NO synthesis by hepatocytes results in a decrease in δ-aminolevulinate synthetase and an increase in heme oxygenase activities, consistent with intracellular heme liberation with consequent effects on these two enzymes. This result also indicates that the increase in heme oxygenase and decrease in δ-aminolevulinate synthetase activities in rats injected with LPS (31Bissell D.M. Hammaker L.E. Arch. Biochem. Biophys. 1976; 176: 91-102Crossref PubMed Scopus (134) Google Scholar, 32Bissell D.M. Hammaker L.E. Arch. Biochem. Biophys. 1976; 176: 103-112Crossref PubMed Scopus (65) Google Scholar) are due to ●NO-induced heme liberation. It is worth noting that even in the presence of NMMA there is still an approximately 2-fold increase in heme oxygenase activity, which may indicate up-regulation by cytokine treatment (33Helqvist S. Polla B.S. Johannesen J. Nerup J. Diabetologia. 1991; 34: 150-156Crossref PubMed Scopus (71) Google Scholar, 34Mitani K. Fujita H. Kappas A. Sassa S. Blood. 1992; 79: 1255-1259Crossref PubMed Google Scholar, 35Fukuda Y. Sassa S. Biochem. Biophys. Res. Commun. 1993; 193: 297-302Crossref PubMed Scopus (35) Google Scholar) that is ●NO-independent. Ferrochelatase, recently discovered to contain an Fe2S2 nonheme iron-sulfur center(36Dailey H.A. Finnegan M.G. Johnson M.K. Biochemistry. 1994; 33: 403-407Crossref PubMed Scopus (178) Google Scholar), catalyzes the insertion of iron into porphyrin. As shown in Fig. 3A, ●NO synthesis also decreases ferrochelatase activity, which represents a newly identified nonheme iron enzymatic target for ●NO. Fig. 3B presents a time course for the changes in the activities of these three enzymes after exposure to SNAP. While a decrease in δ-aminolevulinate synthetase and an increase in heme oxygenase activities require a time lag of 2-3 h (consistent with previously described heme-induced regulatory mechanisms(22Bonkovsky H.L. Zakim D. Boyer T.D. Hepatology. A Textbook of Liver Disease. W. B. Saunders Co., Philadelphia1982: 351-393Google Scholar)), the decrease in ferrochelatase activity is virtually complete within 1 h. This indicates that ●NO inhibits activity of this enzyme by a direct effect, perhaps by destruction of its nonheme iron-sulfur cluster(36Dailey H.A. Finnegan M.G. Johnson M.K. Biochemistry. 1994; 33: 403-407Crossref PubMed Scopus (178) Google Scholar). This inhibition will contribute to a decrease in intracellular heme levels in addition to a decrease in δ-aminolevulinate synthetase and an increase in heme oxygenase activities. Finally, Fig. 3C demonstrates that ●NO synthesis results in increased heme oxygenase transcription, as determined by Northern blot analysis using a cDNA probe to human HO1(19Yoshida T. Biro P. Cohen T. Müller R.M. Shibahara S. Eur. J. Biochem. 1988; 171: 457-461Crossref PubMed Scopus (267) Google Scholar). The increase occurs slightly after induction of ●NO synthase and concomitant with ●NO synthesis (appearance of NO2−+ NO3− in the medium, NOx). Heme oxygenase mRNA is induced also by SNAP, without the lag required for induction of ●NO synthase by the cytokine mixture, demonstrating that ●NO alone (without cytokines) can induce heme oxygenase. Although not shown, addition of 8-bromo-cyclic GMP (20 μM) did not induce an increase in heme oxygenase mRNA, indicating that the effect is not due to a cGMP signaling mechanism. With regard to the possible mechanism(s) of ●NO-induced heme loss, previous studies in oxygen-free conditions have shown that ●NO binds to both the reduced and oxidized forms of CYP and that conversion to the inactive P420 form can take place(37O'Keeffe D.H. Ebel R.E. Peterson J.A. J. Biol. Chem. 1978; 253: 3509-3516Abstract Full Text PDF PubMed Google Scholar). In the presence of oxygen, Wink et al.(38Wink D.A. Osawa Y. Darbyshire J.F. Jones C.R. Eshenaur S.C. Nims R.W. Arch. Biochem. Biophys. 1993; 300: 115-123Crossref PubMed Scopus (347) Google Scholar) have shown that ●NO causes both a transient, reversible inhibition of enzymatic activity and a long lasting irreversible inhibition. The transient reversible inhibition may be due to formation of nitrosyl-heme complexes; the irreversible inhibition is substantially prevented by the addition of albumin, suggesting the formation of a reactive nitrogen oxide species from the reaction of ●NO with O2 (to form nitrosonium ion equivalents [NO+]) or with ●O2− (to produce peroxynitrite, ONOO−). Early work demonstrated the formation of nitrosonium ion equivalents ([NO+]) in activated macrophages synthesizing ●NO, and similar chemical reactivity is exhibited by the reaction of ●NO with O2 in aqueous solution(39Miwa M. Stuehr D.J. Marletta M.A. Wishnok J.S. Tannenbaum S.R. Carcinogenesis. 1987; 8: 955-958Crossref PubMed Scopus (194) Google Scholar, 40Wink D.A. Darbyshire J.F. Nims R.W. Saavedra J.E. Ford P.C. Chem. Res. Toxicol. 1993; 6: 23-27Crossref PubMed Scopus (478) Google Scholar). In addition, activated macrophages synthesize peroxynitrite(41Ischiropoulos H. Zhu L. Beckman J.S. Arch. Biochem. Biophys. 1992; 298: 446-451Crossref PubMed Scopus (1084) Google Scholar). Previous studies have shown that both heme and albumin are nucleophilic targets for nitrosation (42Bonnett R. Charalambides A.A. Martin R.A. J. Chem. Soc. Perkin Trans. I. 1978; : 974-980Crossref Scopus (28) Google Scholar, 43Stamler J.S. Jaraki O. Osborne J. Simon D.I. Keaney J. Vita J. Singel D. Valeri C.R. Loscalzo J. Proc. Natl. Acad. Sci. U. S. A. 1992; 89: 7674-7677Crossref PubMed Scopus (1122) Google Scholar) and that albumin is a target for peroxynitrite(44Radi R. Beckman J.S. Bush K.M. Freeman B.A. J. Biol. Chem. 1991; 266: 4244-4250Abstract Full Text PDF PubMed Google Scholar). It is likely that all hemoproteins do not respond identically to endogenous nitrogen oxides. For example, as shown in Fig. 1B there appears to be a subpopulation of CYP proteins that are resistant to 60-min exposure to ●NO, and mitochondrial cytochromes are also resistant to enzymatic inhibition(1Nathan C. FASEB J. 1992; 6: 3051-3064Crossref PubMed Scopus (4128) Google Scholar, 2Hibbs Jr., J.B. Taintor R.R. Vavrin Z. Granger D.L. Drapier J.C. Amber I.J. Lancaster Jr., J.R. Moncada S. Higgs E.A. Nitric Oxide from L-Arginine: A Bioregulatory System. Elsevier Science Publishers B.V., Amsterdam1990: 189-223Google Scholar). In addition, at least two enzymes (cyclooxygenase (45Salvemini D. Misko T.P. Masferrer J.L. Seibert K. Currie M.G. Needleman P. Proc. Natl. Acad. Sci. U. S. A. 1993; 90: 7240-7244Crossref PubMed Scopus (1376) Google Scholar) and guanylyl cyclase(46Ignarro L.J. Annu. Rev. Pharmacol. Toxicol. 1990; 30: 535-560Crossref PubMed Scopus (1215) Google Scholar)) are stimulated by ●NO. In the latter case, the results presented here may suggest that nitrosylation of the heme in guanylate cyclase is a transient event, terminated by dissociation of the NO-heme from the enzyme. This may explain the transient nature of stimulation of cGMP synthesis by ●NO. These results also may have relevance to other well known pathophysiological conditions. For example, formation of ●NO by the reticuloendothelial system under conditions of immune activation may result in decreased erythropoiesis, perhaps contributing to the well known anemia of inflammation and infection(47Fuchs D. Hausen A. Reibnegger G. Werner E.R. Werner-Felmayer G. Dierich M.P. Wachter H. Eur. J. Haematol. 1991; 46: 65-70Crossref PubMed Scopus (118) Google Scholar). We thank Karla Wasserloos and William M. Konitsky for excellent technical assistance and are grateful to Dr. Shigeki Shibahara, Tohuku University, Japan for the gift of plasmid, pHHO1, containing cDNA to the human heme oxygenase 1 gene." @default.
• W2094764360 created "2016-06-24" @default.
• W2094764360 creator A5033569480 @default.
• W2094764360 creator A5038425390 @default.
• W2094764360 creator A5038844622 @default.
• W2094764360 creator A5054964892 @default.
• W2094764360 creator A5071772331 @default.
• W2094764360 creator A5073767193 @default.
• W2094764360 date "1995-03-01" @default.
• W2094764360 modified "2023-09-26" @default.
• W2094764360 title "Loss and Degradation of Enzyme-bound Heme Induced by Cellular Nitric Oxide Synthesis" @default.
• W2094764360 cites W1500094754 @default.
• W2094764360 cites W1531171254 @default.
• W2094764360 cites W1531443259 @default.
• W2094764360 cites W1538196126 @default.
• W2094764360 cites W1541059747 @default.
• W2094764360 cites W1554444467 @default.
• W2094764360 cites W1569157818 @default.
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• W2094764360 cites W1986368539 @default.
• W2094764360 cites W1990139307 @default.
• W2094764360 cites W1996632010 @default.
• W2094764360 cites W2002192155 @default.
• W2094764360 cites W2003620621 @default.
• W2094764360 cites W2004343006 @default.
• W2094764360 cites W2018556115 @default.
• W2094764360 cites W2025334605 @default.
• W2094764360 cites W2026182346 @default.
• W2094764360 cites W2030864821 @default.
• W2094764360 cites W2036900137 @default.
• W2094764360 cites W2042211608 @default.
• W2094764360 cites W2058494523 @default.
• W2094764360 cites W2070154083 @default.
• W2094764360 cites W2072256632 @default.
• W2094764360 cites W2073941833 @default.
• W2094764360 cites W2089747387 @default.
• W2094764360 cites W2090899269 @default.
• W2094764360 cites W2092330256 @default.
• W2094764360 cites W2092517767 @default.
• W2094764360 cites W2094745968 @default.
• W2094764360 cites W2097790923 @default.
• W2094764360 cites W2107993264 @default.
• W2094764360 cites W2119088209 @default.
• W2094764360 cites W2153491246 @default.
• W2094764360 cites W2248563070 @default.
• W2094764360 cites W2402653590 @default.
• W2094764360 cites W57005361 @default.
• W2094764360 cites W876372620 @default.
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