HCV/TLR3 modulated the expression of RANTES in murine activated hepatic stellate cells

Background/Aims: RANTES/CCL5 has been identified as a central mediator in liver fibrogenesis. However, the interaction between HCV/TLR3 and RANTES and its functional role for hepatic stellate cells (HSC) is not well understood. Methods: Wide-type and TLR3-/- mice were treated with TLR3 ligands (Poly I: C). The expression of hepatic RANTES and IFN-β was detected by quantitative real time RT-PCR (qrt-PCR). Primary HSCs were isolated from human liver tissues or C57BL/6J wild-type mice. HSCs were stimulated with different TLR ligands for 20h. RANTES mRNA expression and protein production were assessed by qrt-PCR and ELISA, respectively. Activated HSC were stimulated with recombinant murine RANTES for different time points. Supernatants were collected and co-incubated with MH1 cell lines, and the expression of HCV in MH1 cells, as well fibrosis-related genes (TGFβ1, –2, –3; PDGF C, -D; CTGF, RhoA, MMP13) and TLR signaling pathway-related genes of HSCs were estimated by qrt-PCR, Functional assays included cell proliferation and migration transwell assays. Results: Only TLR3 stimulation could induce the secretion of RANTES in HSC. This could be verified by in vitro transfection of TLR3 siRNA into primary HSCs, and in vivo treatment with Poly I: C, as RANTES production could be completely blocked whereas secretion of IFN-β was still detectable. TLR3-induced RANTES expression in HSC was time- and dose-dependent. In addition, TLR3 could stimulate the proliferation and migration of HSC via the RANTES signaling pathway, but had little effect upon the phenotype transformation of HSCs, which was consistent with the down-regulated expression of TGF-β. Conclusions: These data show that TLR3/HCV is a potent inductor of RANTES in HSC which leads to up-regulation of fibrosis-related genes. Thus, therapies that are aimed at the suppression of RANTES may provide useful strategies to inhibit HCV-induced liver fibrosis when HCV eradication can not be achieved.

HCV - Hepatische Sternzellen - RANTES - TLR-System