Leonurine Attenuates CCl₄-Induced Hepatic Fibrosis in Mice via the Hippo-YAP Pathway

The repair response to persistent damage in the liver manifests as liver fibrosis. Leonurine (Leo), an herbal remedy from traditional Chinese medicine, exhibits multiple biological activities such as antioxidant and anti-inflammatory effects. Nevertheless, research exploring Leo's influence on liver fibrosis remains absent. This study aims to investigate the effect of Leo on liver fibrosis and clarify the mechanisms at play.

We employed a mouse model of liver fibrosis induced by carbon tetrachloride (CCl₄) and utilized LX-2 cells to investigate the mechanisms through which Leo exerts its effects.

Mice administered CCl₄ displayed an elevated hepatic index, considerable necrosis as revealed by H&E staining, and significantly heightened serum markers of liver injury (ALT and AST). Conversely, mice treated with Leo showed a marked reduction in liver damage, coupled with diminished levels of inflammatory mediators and less infiltration of hepatic macrophages. Importantly, Leo demonstrated protective effects against CCl₄-induced hepatocyte apoptosis in vivo and promoted apoptosis in hepatic stellate cells in vitro. Staining with Sirius red and Masson confirmed that Leo substantially reduced collagen deposition. Furthermore, Leo treatment led to decreased quantities of α-smooth muscle actin (α-SMA) and collagen type I (COL1A1) in both fibrotic tissues and LX-2 cells. Additionally, the administration of Leo was associated with a significant decrease in YAP protein levels, along with an increase in YAP phosphorylation at Ser 397 via the MST-LATS kinase signaling pathway, facilitating the degradation of YAP.

The findings indicate that Leo may exert a protective effect against liver fibrosis through the inhibition of the Hippo-YAP signaling pathway, underscoring its potential as a therapeutic agent for treating hepatic fibrosis.