Hatano E, Bennett B L, Manning A M, Qian T, Lemasters J J, Brenner D A
Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
Gastroenterology. 2001 Apr;120(5):1251-62. doi: 10.1053/gast.2001.23239.
Hepatocyte apoptosis is induced by tumor necrosis factor alpha (TNF-alpha) and Fas ligand. Although nuclear factor-kappaB (NF-kappaB) activation protects hepatocytes from TNF-alpha-mediated apoptosis, the NF-kappaB responsive genes that protect hepatocytes are unknown. Our aim was to study the role of NF-kappaB activation and inducible nitric oxide synthases (iNOSs) in TNF-alpha- and Fas-mediated apoptosis in hepatocytes.
Primary cultures of hepatocytes from wild-type and iNOS knockout mice were treated with TNF-alpha, the Fas agonistic antibody Jo2, a nitric oxide (NO) donor (S-nitroso-N-acetylpenicillamine), an NO inhibitor (N(G)-methyl-L-arginine acetate), and/or adenovirus-expressing NF-kappaB inhibitors.
The IkappaB superrepressor and a dominant-negative form of IkappaB kinase beta (IKKbeta) inhibited NF-kappaB binding activity by TNF-alpha or Jo2 and sensitized hepatocytes to TNF-alpha- and Jo2-mediated apoptosis. TNF-alpha and Jo2 induced iNOS messenger RNA and protein levels through the induction of NF-kappaB. S-nitroso-N-acetylpenicillamine inhibited Bid cleavage, the mitochondrial permeability transition, cytochrome c release, and caspase-8 and -3 activity, and reduced TNF-alpha- and Fas-mediated death in hepatocytes expressing IkappaB superrepressor. N(G)-methyl-L-arginine acetate partially sensitized hepatocytes to TNF-alpha- and Fas-mediated cell killing. TNF-alpha alone or Jo2 alone induced moderate cell death in hepatocytes from iNOS(-)/(-) mice.
NO protects hepatocytes from TNF-alpha- and Fas-mediated apoptosis. Endogenous iNOS, which is activated by NF-kappaB via IKKbeta, provides partial protection from apoptosis.
肿瘤坏死因子α（TNF-α）和Fas配体可诱导肝细胞凋亡。尽管核因子κB（NF-κB）激活可保护肝细胞免受TNF-α介导的凋亡，但保护肝细胞的NF-κB反应性基因尚不清楚。我们的目的是研究NF-κB激活和诱导型一氧化氮合酶（iNOS）在TNF-α和Fas介导的肝细胞凋亡中的作用。
用TNF-α、Fas激动性抗体Jo2、一氧化氮（NO）供体（S-亚硝基-N-乙酰青霉胺）、NO抑制剂（N(G)-甲基-L-精氨酸乙酸盐）和/或表达NF-κB抑制剂的腺病毒处理野生型和iNOS基因敲除小鼠的原代肝细胞培养物。
IkappaB超抑制剂和IkappaB激酶β（IKKβ）的显性负性形式可抑制TNF-α或Jo2诱导的NF-κB结合活性，并使肝细胞对TNF-α和Jo2介导的凋亡敏感。TNF-α和Jo2通过诱导NF-κB来诱导iNOS信使核糖核酸和蛋白质水平。S-亚硝基-N-乙酰青霉胺抑制Bid裂解、线粒体通透性转换、细胞色素c释放以及半胱天冬酶-8和-3活性，并减少表达IkappaB超抑制剂的肝细胞中TNF-α和Fas介导的死亡。N(G)-甲基-L-精氨酸乙酸盐使肝细胞对TNF-α和Fas介导的细胞杀伤部分敏感。单独的TNF-α或单独的Jo2在iNOS(-)/(-)小鼠的肝细胞中诱导中度细胞死亡。
NO保护肝细胞免受TNF-α和Fas介导的凋亡。由NF-κB通过IKKβ激活的内源性iNOS提供了部分抗凋亡保护。
