Genes Inducing iPS Phenotype Play a Role in Hepatocyte Survival and Proliferation In Vitro and Liver Regeneration In Vivo

Abstract

Induced pluripotent stem cells have taken over somatic cell nuclear transfer technology in studies targeting disease models and regenerative medicine. Self-renewal factors/reprogramming factors such as Oct3/4, Nanog, Sox2, Klf4, and cMyc have been used to induce pluripotency in various differentiated somatic cells. The neuronal repressor REST (RE-1 silencing transcription factor; also called NRSF) has previously been shown to maintain self renewal and pluripotency in mouse embryonic stem cells by maintaining the expression Oct3/4, Nanog, Sox2, and cMyc. In the present work we report that primary rat hepatocytes express REST along with some of the self-renewal factors in culture. Their expression is upregulated under the influence of hepatocyte growth factor (HGF) and epidermal growth factor (EGF). The reprogramming factors are also upregulated after 70% partial hepatectomy (PHx) in vivo. REST inhibition in primary hepatocyte culture by shRNA technique resulted in downregulation of reprogramming factors' mRNA and protein levels, which was accompanied by increased apoptosis and decreased rate of proliferation in the REST-inhibited group as compared to controls. These findings suggest the significance of transcription factor REST and self-renewal factors in survival and proliferation of primary hepatocytes in culture and their potential role in liver regeneration in vivo.