Nitric oxide suppresses the expression of Bcl-2 binding protein BNIP3 in hepatocytes.
Nitric oxide (NO) is not only an important signaling molecule, but it also regulates the expression of a number of genes in the liver. We have previously shown that apoptosis in hepatocytes exposed to tumor necrosis factor-alpha and actinomycin D is prevented by NO derived from the inducible nitric-oxide synthase (iNOS), by mechanisms that are both dependent on and independent of modulation of cyclic guanosine monophosphate (cGMP) subsequent to activation of soluble guanylyl cyclase (sGC). We hypothesize that one mechanism by which NO exerts these effects is by regulating the expression of genes involved in apoptosis. We used differential display-polymerase chain reaction to isolate NO-regulated genes in hepatocytes from iNOS knockout mice (to eliminate endogenous inducible NO production). Using this analysis, we identified a NO-suppressed gene fragment homologous with the pro-apoptotic Bcl-2 binding protein BNIP3. Northern analysis confirmed the NO-dependent suppression of BNIP3 in cultured cells. Similarly, the NO donor S-nitroso-N-acetyl-dl-penicillamine (1-1000 microm) down-regulated the expression of BNIP3 in both iNOS knockout and wild-type hepatocytes. This effect of NO was reversed by the sGC inhibitor 1H-(1,2,4)-oxadiazole[4,3-a]quinoxalon-1-one (ODQ),suggesting the involvement of the sGC/cGMP pathway in the modulation of BNIP3 by NO. We propose that suppression of BNIP3 expression is one sGC/cGMP-dependent mechanism by which NO might affect the process of hepatocyte apoptosis.
Zamora
R
R
Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15261, USA. zamorar@pitt.edu
Alarcon
L
L
Vodovotz
Y
Y
Betten
B
B
Kim
P K
PK
Gibson
K F
KF
Billiar
T R
TR
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis; D015152:Blotting, Northern; D015153:Blotting, Western; D002470:Cell Survival; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000378:metabolism; D003609:Dactinomycin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D018014:Gene Transfer Techniques; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors / Q000378:metabolism; D022781:Hepatocytes / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis*; D051379:Mice; D018345:Mice, Knockout; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D009573:Nitrites / Q000378:metabolism; D010477:Perfusion; D011485:Protein Binding; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology; D015398:Signal Transduction; D012977:Sodium Nitrite / Q000494:pharmacology; D013997:Time Factors; D025521:Tumor Suppressor Proteins; D015854:Up-Regulation
C090121:BNIP3 protein, human; C116838:BNIP3L protein, human; D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; D020030:Nitric Oxide Donors; D009573:Nitrites; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D025521:Tumor Suppressor Proteins; D003609:Dactinomycin; D009569:Nitric Oxide; D012313:RNA; D026423:S-Nitroso-N-Acetylpenicillamine; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; C496318:Nos2 protein, rat; D006162:Guanylate Cyclase; D012977:Sodium Nitrite