FR-167653, a selective p38 MAPK inhibitor, exerts salutary effect on liver cirrhosis through downregulation of Runx2

Abstract

Liver cirrhosis remains a difficult-to-treat disease with a substantial morbidity and mortality rate. There is an emerging body of data purporting a pivotal role of the activated p38 mitogen-activated protein kinase (MAPK) in the process of cirrhosis. Several anticirrhotic agents have been developed over the past few years, and most of them exert their effects by indirectly inhibiting the p38 pathway. Effect of a selective p38 inhibitor is yet to be reported. In this study, we evaluated the salutary effect of FR-167653 (FR), a selective p38 inhibitor, in a carbon tetrachloride (CCl4)-induced rat cirrhotic model. Twenty rats were assigned into four groups: Sham, olive oil only; Control, CCl4 in olive oil; FR50, FR 50 mg/kg/day and CCl4; and FR100, FR 100 mg/kg/day and CCl4. FR dose-dependently inhibited activation of p38 and had an ameliorating effect on cirrhosis formation. Significant dose-dependent reduction in α-smooth muscle actin immunostaining and hydroxyproline content of the liver was noticed in the FR-treated rats. Also densitometric analysis showed a significant reduction in azan-stained area in the FR-treated rats. These fibrotic changes were observed in the myofibroblasts including the hepatic stellate cells and portal fibroblasts. mRNA expression of runt-related protein 2 (Runx2), a profibrogenic transcription factor, was significantly low in FR-treated livers, indicating that Runx2 might be a key downstream regulator of the p38 pathway. A similar reduction in expression of Smad4 and tissue inhibitor of metalloproteinase-1 was noticed in the FR-treated rats. In conclusion, FR treatment exerted a significant beneficial effect in a CCl4-induced rat cirrhotic model. The ameliorating effect of FR could be partially attributable to an inhibition of the Smad4/p38/Runx2 axis in the cirrhotic liver.