Pertussis Toxin, an Inhibitor of Gαi PCR, Inhibits Bile Acid- and Cytokine-Induced Apoptosis in Primary Rat HepatocytesReportar como inadecuado

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Excessive hepatocyte apoptosis is a common event in acute and chronic liver diseases leading to loss of functional liver tissue. Approaches to prevent apoptosis have therefore high potential for the treatment of liver disease. G-protein coupled receptors GPCR play crucial roles in cell fate proliferation, cell death and act through heterotrimeric G-proteins. GαiPCRs have been shown to regulate lipoapoptosis in hepatocytes, but their role in inflammation- or bile acid-induced apoptosis is unknown. Here, we analyzed the effect of inhibiting GαiPCR function, using pertussis toxin PT, on bile acid- and cytokine-induced apoptosis in hepatocytes. Primary rat hepatocytes, HepG2-rNtcp cells human hepatocellular carcinoma cells or H-4-II-E cells rat hepatoma cells were exposed to glycochenodeoxycholic acid GCDCA or tumor necrosis factor-α TNFα-actinomycin D ActD. PT 50–200 nmol-L was added 30 minutes prior to the apoptotic stimulus. Apoptosis caspase-3 activity, acridine orange staining and necrosis sytox green staining were assessed. PT significantly reduced GCDCA- and TNFα-ActD-induced apoptosis in rat hepatocytes −60%, p<0.05 in a dose-dependent manner with no shift to necrosis, but not in HepG2-rNtcp cells or rat H-4-II-E cells. The protective effect of pertussis toxin was independent of the activation of selected cell survival signal transduction pathways, including ERK, p38 MAPK, PI3K and PKC pathways, as specific protein kinase inhibitors did not reverse the protective effects of pertussis toxin in GCDCA-exposed hepatocytes. Conclusion: Pertussis toxin, an inhibitor of GαiPCRs, protects hepatocytes, but not hepatocellular carcinoma cells, against bile acid- and cytokine-induced apoptosis and has therapeutic potential as primary hepatoprotective drug, as well as adjuvant in anti-cancer therapy.

Autor: Golnar Karimian , Manon Buist-Homan, Klaas Nico Faber, Han Moshage



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