[Salianic-acid B inhibits MAPK signaling in activated rat hepatic stellate cells]

To investigate the inhibiting effect of salianic-acid B (SA-B) on mitogen-activated protein kinase (MAPK) Signaling in activated rat hepatic stellate cells (HSCs).

HSCs were isolated from normal rat by in situ perfusion and Nycodenz density-gradient centrifugation method. HSCs were primarily cultured on uncoated plastic for 7 days. Then cells were stimulated with 10ng/ml transforming growth factor-beta1 (TGF-beta1) after incubated with 10-6 M/L SA-B. The effects of SA-B on Extracellular-regulated kinase (ERK) expression and its phosphorylation. Transforming growth factor beta1 receptor I (TbetaR I) and transforming growth factor beta1 receptor II (TbetaR II) on HSCs, type I collagen expression in HSC Induced by TGF-beta1 were detected with western blot assay. Quantity of Type I collagen in the medium of HSCs was detected by ELISA. Matrix metalloproteinase 2, 9, 13 (MMP-2, MMP-9 and MMP-13) in the medium of HSCs was tested by Zymography.

The phosphorylation of ERK1/2 in HSCs with or without TGF-beta1 was inhibited by SA-B. The expression of TbetaR I and TbetaR II on HSCs can not be affected by SA-B. The synthesization of Type I collagen in HSCs was decreased by SA-B; The synthesization and secretion of type I collagen in HSCs with TGF-beta1 were reduced by SA-B too. SA-B had no effect on the activity of MMP-2 and MMP-13, but induced the activity of MMP-13.

SA-B inhibits ERK signaling induced by TGF-b1 in HSC. This inhibition has no association with the expression of TbetaR I and TbetaR II on HSCs. SA-B reduces the synthesization and secretion of Type I collagen in HSC by means of inhibiting TGF-beta1 signaling, which might be not related to the degrading activities of MMPs.