Cell cycle progression and lipid metabolism are well-coordinated processes required for proper cell proliferation. In liver diseases that arise from dysregulated lipid metabolism, proliferation is diminished. To study the outcome of CDK1 loss and blocked hepatocyte proliferation on lipid metabolism and the consequent impact on whole-body physiology, we performed lipidomics, metabolomics, and RNA-seq analyses on a mouse model. We observed reduced triacylglycerides in liver of young mice, caused by oxidative stress that activated FOXO1 to promote expression of ATGL. Additionally, we discovered that hepatocytes displayed malfunctioning b-oxidation, reflected by increased acylcarnitines and reduced b-hydroxybutyrate. This led to elevated plasma free fatty acids, which were transported to the adipose tissue for storage and triggered greater insulin secretion. Upon aging, chronic hyperinsulinemia resulted in insulin resistance and hepatic steatosis through activation of LXR. Here we demonstrate that loss of hepatocyte proliferation is not only an outcome but possibly causative for liver pathology.
This work was supported by A*STAR (IAF-ICP I1901E0040), Singapore International Graduate Award, National Research Foundation (NRF2016-CRP001-103), National Medical Research Council (NMRC-CG-M009), Life Sciences Institute of the National University of Singapore, Swedish Foundation for Strategic Environmental Research (Dnr IRC15-0067) and Swedish Research Council (Dnr 2009-1039).