Effects Of PNPLA7 On The HCV Life Cycle And Its Role In Hepatic Gluconeogenesis Disorders Induced By HCV Infection

Objective:The aim is to explore the role of patatin-like phospholipase domain containing protein 7 in the process of HCV entry,translation,replication,assembly and and the effect on secretion gluconeogenesis disorder caused by hepatitis C virus infection.Methods: We knocked down the PNPLA7 at cell level by small RNA interference and lentivirus.And then we explored the fuction of PNPLA7 in the process of virus entry,translation,copy,assembly,budding and specific infectivity by detecting the activity of luciferase,the intracellular and extracellular titer and RNA of virus.Protein-protein interaction was detected by immunofluorescence and co-immunoprecipitation,the expression level of the indicated genes was detected by QPCR and WB.The role of PNPLA7 in the process of gluconeogenesis disorder caused by HCV infection was analysised by QPCR and WB.Results: The expression of PNPLA7 was up-regulated following HCV infection.Moreover,HCV-infected Huh7 cells exposed to the endoplasmic reticulum stress inhibitor(GSK2606414)showed decreased PNPLA7 levels compared with those exposed to vehicle.Following the knockdown of PNPLA7,the RNA and protein level of HCV were significantly downregulated,indicating that PNPLA7 played an important role in HCV proliferation.Further analysis indicated that PNPLA7 knockdown significantly reduced HCV propagation at the assembly and secretion step but not the entry,RNA replication,and protein translation steps of the life cycle.And PNPLA7 depletion reduced the expression of the key genes in VLDL assembly and secretion,such as Cide B and Apo E.Meanwhile,PNPLA7 was involved in the assembly and budding of HCV by interacting with HCV non-structural protein NS5 A.On the other hand,HCV infection promoted hepatic gluconeogenesis.PNPLA7 depletion resulted in a marked decrease of HCV-induced PEPCK and G6 Pase expression in HCV-infected cells.Glucose production in HCV-infected cells was consistently dramatically reduced compared with the control following PNPLA7 knockdown.Furthermore,the level of CREB phosphorylation wass reduced,and the level of PGC-1? was also decreased significantly.Therefore,HCV-induced PNPLA7 upregulation enhanced gluconeogenesis by promoting the expression of gluconeogenic genes,including phosphoenolpyruvatecarboxykinase and glucose-6phosphatase,indicating a major role for PNPLA7 in the development of HCV-associated exaggerated gluconeogenic responses.Conclusion: The endoplasmic reticulum stress caused by HCV infection could induce the expression of PNPLA7.PNPLA7 is involved in the assembly and secretion of HCV by regulating the expression level of Cide B and Apo E and the interacting with the non-structural protein NS5 A.On the other hand,PNPLA7 influences the process of gluconeogenesis by regulating the phosphorylation level of CREB and the expression level of PGC-1?.