Schistosoma japonicum protein SjP40 inhibits TGF-β1-induced activation of hepatic stellate cells.

SjP40 is a major egg antigen of Schistosoma japonicum. In the present study, the authors investigated the effect of SjP40 in vitro on transforming growth factor-β1 (TGF-β1)- stimulated hepatic stellate cells (HSCs). LX-2, an immortalized human HSC line, was treated with purified recombinant SjP40 (rSjP40) in the presence or absence of TGF-β1. Quantitative real-time polymerase chain reaction and western blot analysis were performed to determine messenger ribonucleic acid and protein of fibrogenic genes and TGF-β signaling pathway. The results showed that expression of fibrogenic genes was significantly reduced by rSjP40. Furthermore, rSjP40 also suppressed the TGF-β1-induced upregulation of Smads and ERK proteins. We also found that the effect of rSjP40 on HSCs was similar to SB431542, an inhibitor of type I TGF-β receptor. In conclusion, the data suggest that SjP40 attenuates HSC activation, which might be, at least in part, mediated by inhibiting the TGF-β and ERK signaling pathways.