This study demonstrates that CCL2 is a key molecule for the development of metabolic and histological alterations in the liver of mice sensitive to the development of hyperlipidemia and hepatic steatosis, a finding with potential to identify new therapeutic targets in liver diseases.
IP-KO mice developed steatohepatitis at 5 wk with augmented histologic derangements accompanied by increased hepatic monocyte chemoattractant protein-1 (MCP-1) and TNF-α concentrations.
Both liver tissue and blood samples were processed to evaluate steatosis and NASH changes in histology (Oil Red, Sirius Red and H&E); presence of endothelial damage (CD31, Moesin/p-Moesin, Akt/p-Akt, eNOS/p-eNOS), oxidative stress (iNOS) and fibrosis (αSMA, Col1, PDGF, VEGF) proteins in liver tissue; and inflammatory (IL6, IL10, MCP-1, IL17α, TNFα), liver biochemical function, and hormonal (leptin, ghrelin, visfatin and insulin) alterations in plasma.
These findings suggest that an increase in MCP-1 expression in adipose tissue contributes to the macrophage infiltration into this tissue, insulin resistance, and hepatic steatosis associated with obesity in mice.
In vitro, CVC inhibited CCL2-induced increases in hepatocyte fatty acid synthase (Fasn) and adipose differentiation-related protein (Adrp), whereas it augmented acyl-coenzyme A oxidase 1 (Acox-1), proliferator-activated receptor gamma co-activator alpha (Pgc1α) and uncoupling protein 2 expression, suggesting mechanisms for attenuated hepatocyte steatosis.
Neutralization of CD44 in mice with steatohepatitis strongly decreased the macrophage infiltration and chemokine ligand (CCL)2 expression with a partial correction of liver inflammation and injury.