Reprogramming factor Oct4 is crucial for Trans differentiation of Hepatocytes to Biliary epithelial cells

Abstract

Trans differentiation of liver epithelial cells (hepatocytes and biliary cells) into each other provides a rescue mechanism in liver disease under situations where either cell compartment fails to regenerate by itself. The mechanisms underlying such trans differentiation of terminally differentiated epithelial cells are not fully elucidated. Recently we reported that adult rat liver expresses reprogramming factors Oct4, Nanog, and KLF4, and their expression is important for hepatocyte proliferation and liver regeneration. To test if reprogramming factor Oct4 plays a role in trans differentiation of hepatocytes to BECs, we used the hepatocyte organoid culture: an in vitro hepatocyte to biliary trans differentiation model. In this model, primary hepatocytes when plated on collagen coated roller bottles and cultured in presence of HGF, EGF, and dexamethasone, trans differentiate to form BECs between 6–15 days in culture. We found that Oct4 is upregulated at day 6 in this model as assessed by mRNA and protein levels suggesting its possible involvement in trans differentiation. When expression of Oct4 was blocked in hepatocytes using adenovirus containing Oct4 shRNA, there was a significant decrease in the number of biliary cells as compared to controls as assessed by biliary marker HNF1‐beta, strongly supporting the role of Oct4 in trans differentiation of hepatocyte to biliary epithelial cells. Moreover, Oct4 inhibited group shows significantly less SOX9, YAP, and Notch (also shown to be involved in trans differentiation) expression as compared to controls. Experiments to investigate mechanisms through which Oct4 might regulate trans differentiation are under way.Support or Funding Information Center for Chronic Disorders of Aging. American Association of Colleges of Pharmacy New Investigator Award.