Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.6.1.2 (alanine aminotransferase)
26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tumor necrosis factor (TNF) induces hepatitis when injected in human beings or in rodents. The molecular mechanism by which TNF induces hepatic distress remains largely unknown, although induction of apoptosis of hepatocytes appears to be an essential step. In order to increase the therapeutic value of TNF, we have studied the protective activity of several molecules and found that four chemically totally different substances confer significant protection in the model of TNF-induced lethal hepatitis in mice sensitized with D-(+)-galactosamine (GalN), but not in mice sensitized with actinomycin-D (ActD) or against anti-Fas-induced lethal hepatitis. Verapamil, a calcium-channel blocker, tannic acid, picotamide, a thromboxane A(2) receptor antagonist, and K76COOH, an inhibitor, amongst others, of complement, protected significantly against induction of lethality, release of the liver-specific enzyme alanine aminotransferase (ALT) and induction of apoptosis in the liver after TNF/GalN, except for K76COOH, which paradoxically increased ALT values after challenge, and which also protected against TNF/GalN in complement-deficient mice. The data suggest that activation of platelets and neutrophils, as well as induction of inflammation occur in the TNF/GalN model, but not in the TNF/ActD or anti-Fas models, in which direct induction of apoptosis of hepatocytes may be more relevant. The protective activity of the drugs may lead to an increase in therapeutic value of TNF.
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PMID:Tumor necrosis factor-induced lethal hepatitis: pharmacological intervention with verapamil, tannic acid, picotamide and K76COOH. 1067 38

Aminoguanidine is an inhibitor of inducible nitric oxide synthase (iNOS) and is of potential clinical usefulness. Treatment of mice with anti-Fas antibodies (150 microg/kg, i.v.) induced elevation of plasma alanine aminotransferase activity at 4 h and this elevation was inhibited by pretreatment of mice with aminoguanidine (3, 10 and 30 mg/kg, i.p.). The anti-Fas antibody-induced elevation of caspase-3 activity was inhibited by aminoguanidine (30 mg/kg, i.p.), but the addition of aminoguanidine to the cytosol up to 10(-4) M did not inhibit the caspase-3 activity in vitro. Thus, aminoguanidine prevents anti-Fas antibody-induced hepatitis by affecting the apoptotic pathway upstream of caspase-3 activation.
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PMID:Inhibition of anti-Fas antibody-induced hepatitis by aminoguanidine in mice. 1097 30

The effect of cytokine-independent hepatitis on cytochrome P450 (CYP) gene expression remains unknown. Treatment of mice with anti-Fas antibodies (150 microg/kg, i.v.) caused elevated plasma alanine aminotransferase activity at 4 and 24 h after treatment. Under normal reverse-transcription polymerase chain reaction (RT-PCR) amplification conditions, no effect of anti-Fas antibody-induced hepatitis on hepatic CYP 2E1 and 3A gene expression was observed. But lower cycle RT-PCR amplification revealed slight suppression of hepatic CYP 2E1 gene expression. The present results showed that cytokine-independent hepatitis induced by anti-Fas anti-bodies had only a minimal effect on the suppression of CYP gene expression in the liver.
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PMID:Minimal effect of cytokine-independent hepatitis induced by anti-Fas antibodies on hepatic cytochrome P450 gene expression in mice. 1099 39

Cytotoxic T lymphocytes (CTLs) play an important role in the pathogenesis of viral hepatitis. We studied the expression of mRNAs of perforin and Fas ligand (Fas-L) in biopsy specimens from chronic hepatitis B (CHB) (15 cases) and hepatitis C (CHC) patients (13 cases). Both perforin and Fas-L mRNAs were detected in all cases of both CHB and CHC. No messages were detected in the control livers from two cases of fatty liver, a case of Gilbert's syndrome, and a case of Dubin-Johnson syndrome. Semiquantitative analysis revealed a positive correlation between the intensity of perforin and Fas-L mRNAs in both CHB and CHC. In CHB, the intensity of both perforin and Fas-L mRNAs showed a positive correlation with the histological activity and serum alanine aminotransferase level, while the correlation was not apparent in CHC. These results suggest that both perforin and Fas/Fas-L systems are involved in the pathogenesis of liver cell injury of CHB and CHC.
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PMID:Expression of perforin and Fas ligand mRNA in the liver of viral hepatitis. 1105 Dec 76

Lymphocytes can kill target cells including hepatocytes during various inflammatory diseases by Fas receptor-mediated apoptosis. Caspase-8 is activated at the receptor level, thereby initiating the processing of downstream effector caspases. The aim of this study was to investigate the time course of caspase-8 activation and to evaluate the efficacy of the caspase-8 inhibitor IETD-CHO in a model of Fas-induced apoptosis in vivo. C3Heb/FeJ mice were treated with the anti-Fas antibody Jo-2 (0.6 mg/kg). Western blot analysis demonstrated increased cytochrome c in the cytosol (20 min), which was followed by the progressive activation of caspase-3, -9 (40-120 min), and caspase-8 (120 min). At 90 and 120 min, extensive hemorrhage was observed, indicating damage to sinusoidal lining cells. In addition, high plasma ALT levels (997 +/- 316 U/L) and histological evaluation indicated severe parenchymal cell injury. Parenchymal and nonparenchymal cells showed a similar increase in caspase-3 activity and DNA fragmentation. Treatment with IETD-CHO (10 mg/kg) attenuated the increase in caspase-3 activity and DNA fragmentation by 80-90% and completely prevented hemorrhage and parenchymal cell damage. IETD-CHO also prevented the early release of mitochondrial cytochrome c and the processing of caspase-3, -8, and -9. Thus, our data support the hypothesis that Fas-mediated apoptosis is dependent on caspase-8 activation in hepatocytes and nonparenchymal cells. However, the bulk of procaspase-8 is processed late, suggesting that only a small amount of procaspase-8 may actually be activated at the Fas receptor. This initial signal may be amplified by further activation of caspase-8 by effector caspases, i.e., after mitochondrial activation. Caspase-8 is a promising therapeutic target for inhibition of Fas-mediated apoptosis.
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PMID:Protection against Fas receptor-mediated apoptosis in hepatocytes and nonparenchymal cells by a caspase-8 inhibitor in vivo: evidence for a postmitochondrial processing of caspase-8. 1105 47

We investigated the protective effect of yang-gan-wan (YGW, Pro-Liver pill), a Chinese herbal remedy, against liver apoptosis (programmed cell death) induced by anti-Fas antibody (Jo2). Mice were pretreated daily with 200 mg/kg YGW for 14 days before treatment with 10 microg/20 kg body weight Jo2. YGW significantly reduced the elevated activity of alanine aminotransferase (ALT) and also reduced the elevated activity of sorbitol dehydrogenase (SDH) produced 4 hrs after treatment with Jo2. YGW also increased the survival of mice treated with Jo2 by about 1 hr in 11 out of 16 mice (69%). Most of the mice died 9 hrs after Jo2 injection. This study demonstrates that YGW has protective effects against liver apoptosis induced by Jo2.
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PMID:Yang-gan-wan protects mice against apoptosis induced by anti-Fas antibody (Jo2). 1115 45

The effects of imperatorin and its synthetic derivative, Y355, on anti-Fas antibody-induced mice hepatitis were studied. Pretreatment of mice by intraperitoneal administration of imperatorine or Y355 at 30 mg/kg inhibited more than 80% of the anti-Fas antibody (150 microg/kg, i.v.)-induced elevation of plasma alanine aminotransferase activity. Furthermore, oral administration of imperatorin or Y355 at 100 mg/kg also had an inhibitory effect on anti-Fas antibody-induced hepatitis. Both compounds inhibited anti-Fas antibody (250 microg/kg)-induced caspase-1 and caspase-3 activities. The present results showed the inhibition of anti-Fas antibody-induced hepatitis by imperatorin and Y355, which might be a result of inhibition of caspase activities.
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PMID:Inhibition of anti-Fas antibody-induced mice hepatitis by furocoumarin derivatives. 1117 22

We examined the effects of ZNC-2381 (1-(4-aminophenyl)methyl-3-(3-nitrophenyl)-1,3-dihydroimidazo[4,5-b] pyridine-2-one), a new oral hepatoprotective agent, on hepatocellular caspase-3 activity and apoptosis induced by anti-mouse Fas antibody (anti-Fas ab) in mice. Oral ZNC-2381, administered at doses of 10, 30 and 100 mg/kg 1 h before inducing hepatic injury with anti-Fas ab, dose-dependently inhibited the increase in serum alanine aminotransferase (s-ALT) activity 8 h after injection of anti-Fas ab. Increases in DNA fragmentation (nucleosome assay) and caspase-3 activity in the liver 2 h after injection of anti-Fas ab were also inhibited by ZNC-2381 in a dose-dependent manner. As shown by histopathological examination, ZNC-2381 dose-dependently inhibited the appearance of TUNEL-positive apoptotic cells in the liver. Moreover, in studies in vitro, ZNC-2381 (1- 100 micromol/l) concentration-dependently inhibited increases in DNA fragmentation and caspase-3 activity caused by anti-Fas ab in isolated mouse hepatocytes. N- Acetyl-Asp-Glu-Val-Asp aldehyde (Ac-DEVD-cho), a caspase-3-specific inhibitor, inhibited hepatocellular apoptosis caused by anti-Fas ab both in vivo and in vitro, as well as the increase in s-ALT activity in vivo. These results demonstrate that orally administered ZNC-2381 inhibits hepatocellular apoptosis induced by anti-Fas ab and presents the progression of hepatic injury. We propose that the mechanism of action of ZNC-2381 may involve blockade of the signal transduction pathway (caspase-3) of apoptosis mediated by anti-Fas ab.
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PMID:Effects of a novel hepatoprotective drug, ZNC-2381, on fas-induced hepatocellular caspase-3 activity and apoptosis in mice. 1117 76

Molsidomine is effective in reducing portal hypertension in cirrhosis, but its effect on hepatitis is not known. In the present study, the effect of molsidomine on hepatitis was examined using mouse concanavalin A (Con A)-induced hepatitis and mouse anti-Fas antibody-induced hepatitis. Treatment of mice with Con A caused elevation of plasma alanine aminotransferase (ALT) at 8 and 24 h (n=4). Pretreatment of mice with molsidomine (3, 10, 30 and 100 mg/kg, i.p.) prevented Con A-induced hepatitis. Treatment of mice with anti-Fas antibody (150 microg/kg, i.v.) caused elevation of plasma ALT at 3.5 h. Pretreatment mice with molsidomine (10 mg/kg, i.p.) showed only 47% inhibition of anti-Fas antibody caused elevation of plasma ALT. The present results showed effectiveness of molsidomine in preventing Con A-induced mice hepatitis.
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PMID:Prevention of concanavalin A-induced mice hepatitis by molsidomine. 1117 12

Immunity to allogeneic MHC Ags is weak in rodent livers, raising questions as to the mechanisms that might control responses in this organ. Infection with an adenovirus vector reveals that T cell-mediated immunity to nonself-Ags in the liver is self-limiting. Virus-induced liver injury decreases and coincides with disappearance of virus-specific CTL, concomitant to an increase of apoptotic T cells early after infection. But whereas death in CD4 cells is independent of Fas, perforin, and TNF-alpha, that of CD8 cells requires Fas and not perforin or TNF-alpha pathways. Fas ligand is expressed on liver-infiltrating cells, pointing to death by fratricide that causes almost complete disappearance of virus-specific CTL 4 wk after infection. CTL elimination is virus dose dependent, and high doses induced high alanine aminotransferase values, elevated expression of Fas ligand on CD8 cells, and increased CD8 cell migration into the infected liver.
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PMID:Fas-mediated apoptosis causes elimination of virus-specific cytotoxic T cells in the virus-infected liver. 1120 53


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