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.
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.
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.
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.
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.