Abstract
Type 2 diabetes is an independent risk factor for non-alcoholic steatohepatitis (NASH) progression and its mediators have not been resolved. In this study, a pathogenic role of cellular communication network factor 2 (CCN2) protein in NASH pathology, was investigated in an established preclinical NASH model. Male wild type C57BL/6 mice received either Chow or high fat diet (HFD) for 26 weeks, with some mice in each group randomly selected to receive low dose streptozotocin (STZ: 3 i.p. injections, 65 mg/kg) at 15 weeks to induce type 2 diabetes. In the final 10 of the 26 weeks mice from each group were administered i.p. either rabbit anti-CCN2 neutralizing antibody (CCN2Ab) or as control normal rabbit IgG, at a dose of 150 µg per mouse twice/week. NASH developed in the HFD plus diabetes (HFD+DM) group. Administration of CCN2Ab significantly downregulated collagen I and collagen III mRNA induction and prevented pro-inflammatory MCP-1 mRNA induction in HFD+DM mice. At the protein level, CCN2Ab significantly attenuated collagen accumulation by PSR stain and collagen I protein induction in HFD+DM. Phosphorylation of the pro-fibrotic ERK signalling pathway in liver in HFD+DM was attenuated by CCN2Ab treatment. Intrahepatic CCN1 mRNA was induced, whereas CCN3 was downregulated at both the mRNA and protein levels in HFD+DM. CCN3 down-regulation was prevented by CCN2Ab treatment. This in vivo study indicates that CCN2 is a molecular target in NASH with high fat diet and diabetes, and that regulation of ERK signalling is implicated in this process.