rSJYB1 inhibits collagen type I protein expression in hepatic stellate cells via down-regulating activity of collagen α1 (I) promoter

YB1 is a negative regulator in liver fibrosis. We wondered whether SJYB1, a homologous protein of YB1 from Schistosoma japonicum, has an effect on liver fibrosis in vitro. Recombinant SJYB1 (rSJYB1) protein was expressed in a bacterial system and purified by Ni-NTA His-Bind Resin. A human hepatic stellate cell line, the LX-2 cell line, was cultured and treated with rSJYB1. The role of rSJYB1 on LX-2 cells was then analysed by Western blot and luciferase assay. We succeeded in expressing and purifying SJYB1 in a bacterial system and the purified rSJYB1 could be recognized by S japonicum-infected rabbit sera. Western bolt analysis showed that rSJYB1 inhibited the expression of collagen type I, but had little effect on alpha-smooth muscle actin (alpha-SMA). Further analysis revealed that rSJYB1 inhibited the activity of collagen alpha 1 (I) (COL1A1) promoter and functioned at -1592/-1176 region of COL1A1 promoter. Our data demonstrate that rSJYB1-mediated anti-fibrotic activity involves inhibiting the activity of COL1A1 promoter and subsequently suppressing the expression of collagen type I in hepatic stellate cells.