Francisco Javier Cubero1, Jin Peng2, Lijun Liao3, Huan Su4, Gang Zhao4, Miguel Eugenio Zoubek4, Ricardo Macías-Rodríguez4, Astrid Ruiz-Margain4, Johanna Reißing4, Henning W Zimmermann4, Nikolaus Gassler5, Tom Luedde4, Christian Liedtke4, Maximilian Hatting4, Christian Trautwein6. 1. Department of Internal Medicine III, University Hospital, RWTH, Aachen, Germany; Department of Immunology, Ophtalmology & ORL, Complutense University School of Medicine, Madrid, Spain; 12 de Octubre Health Research Institute (imas12), Madrid, Spain. Electronic address: fcubero@ucm.es. 2. Department of Internal Medicine III, University Hospital, RWTH, Aachen, Germany; Department of Hepatobiliary Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing Jiangsu, China. 3. Department of Internal Medicine III, University Hospital, RWTH, Aachen, Germany; Department of Anesthesiology and Pain Management, Shanghai East Hospital, Tongji University, Shanghai, China. 4. Department of Internal Medicine III, University Hospital, RWTH, Aachen, Germany. 5. Institute of Pathology, Braunschweig Hospital, Braunschweig, Germany. 6. Department of Internal Medicine III, University Hospital, RWTH, Aachen, Germany. Electronic address: ctrautwein@ukaachen.de.
Abstract
BACKGROUND & AIMS: Caspase 8 (CASP8) is the apical initiator caspase in death receptor-mediated apoptosis. Strong evidence for a link between death receptor signaling pathways and cholestasis has recently emerged. Herein, we investigated the role of CASP8-dependent and independent pathways during experimental cholestasis. METHODS: Liver injury was characterized in a cohort of human sera (n = 28) and biopsies from patients with stage IV primary biliary cholangitis. In parallel, mice with either specific deletion of Casp8 in liver parenchymal cells (Casp8Δhepa) or hepatocytes (Casp8Δhep), and mice with constitutive Ripk3 (Ripk3-/-) deletion, were subjected to surgical ligation of the common bile duct (BDL) from 2 to 28 days. Floxed (Casp8fl/fl) and Ripk3+/+ mice were used as controls. Moreover, the pan-caspase inhibitor IDN-7314 was used, and cell death mechanisms were studied in primary isolated hepatocytes. RESULTS: Overexpression of activated caspase 3, CASP8 and RIPK3 was characteristic of liver explants from patients with primary biliary cholangitis. Twenty-eight days after BDL, Casp8Δhepamice showed decreased necrotic foci, serum aminotransferase levels and apoptosis along with diminished compensatory proliferation and ductular reaction. These results correlated with a decreased inflammatory profile and ameliorated liver fibrogenesis. A similar phenotype was observed in Ripk3-/- mice. IDN-7314 treatment decreased CASP8 levels but failed to prevent BDL-induced cholestasis, independently of CASP8 in hepatocytes. CONCLUSION: These findings show that intervention against CASP8 in liver parenchymal cells - specifically in cholangiocytes - might be a beneficial option for treating obstructive cholestasis, while broad pan-caspase inhibition might trigger undesirable side effects. LAY SUMMARY: Loss of caspase 8 - a protein involved in programmed cell death - in liver parenchymal cells protects against experimental cholestasis. Therefore, specific pharmacological intervention against caspase 8 might be a valid alternative for the treatment of obstructive cholestasis in the clinic, whereas broad pan-caspase inhibiting drugs might trigger undesirable side effects.
BACKGROUND & AIMS:Caspase 8 (CASP8) is the apical initiator caspase in death receptor-mediated apoptosis. Strong evidence for a link between death receptor signaling pathways and cholestasis has recently emerged. Herein, we investigated the role of CASP8-dependent and independent pathways during experimental cholestasis. METHODS:Liver injury was characterized in a cohort of human sera (n = 28) and biopsies from patients with stage IV primary biliary cholangitis. In parallel, mice with either specific deletion of Casp8 in liver parenchymal cells (Casp8Δhepa) or hepatocytes (Casp8Δhep), and mice with constitutive Ripk3 (Ripk3-/-) deletion, were subjected to surgical ligation of the common bile duct (BDL) from 2 to 28 days. Floxed (Casp8fl/fl) and Ripk3+/+ mice were used as controls. Moreover, the pan-caspase inhibitor IDN-7314 was used, and cell death mechanisms were studied in primary isolated hepatocytes. RESULTS: Overexpression of activated caspase 3, CASP8 and RIPK3 was characteristic of liver explants from patients with primary biliary cholangitis. Twenty-eight days after BDL, Casp8Δhepamice showed decreased necrotic foci, serum aminotransferase levels and apoptosis along with diminished compensatory proliferation and ductular reaction. These results correlated with a decreased inflammatory profile and ameliorated liver fibrogenesis. A similar phenotype was observed in Ripk3-/- mice. IDN-7314 treatment decreased CASP8 levels but failed to prevent BDL-induced cholestasis, independently of CASP8 in hepatocytes. CONCLUSION: These findings show that intervention against CASP8 in liver parenchymal cells - specifically in cholangiocytes - might be a beneficial option for treating obstructive cholestasis, while broad pan-caspase inhibition might trigger undesirable side effects. LAY SUMMARY: Loss of caspase 8 - a protein involved in programmed cell death - in liver parenchymal cells protects against experimental cholestasis. Therefore, specific pharmacological intervention against caspase 8 might be a valid alternative for the treatment of obstructive cholestasis in the clinic, whereas broad pan-caspase inhibiting drugs might trigger undesirable side effects.
Authors: Francisco Javier Cubero; Mohamed Ramadan Mohamed; Marius M Woitok; Gang Zhao; Maximilian Hatting; Yulia A Nevzorova; Chaobo Chen; Johannes Haybaeck; Alain de Bruin; Matias A Avila; Mark V Boekschoten; Roger J Davis; Christian Trautwein Journal: Hepatol Commun Date: 2020-04-16