Objective  To determine the effect of human truncated variant of hepatocyte growth factor (tvNK1) on transforming growth factor-β1 (TGF-β1)-induced fibrosis in LX-2 cells.

  Methods  The small ubiquitin-related modifier (SUMO) and tvNK1 genes were obtained with PCR and the fusion gene SUMO-tvNK1 with over-lap PCR. The expression vector pET28a/SUMO-tvNK1 was constructed and the soluble recombinant SUMO-tvNK1 protein was expressed in Escherichia coli. The SUMO-tvNK1 protein was purified with Ni²⁺-affinity chromatograph and cleaved with a SUMO-specific protease (Ulp1) to obtain the tvNK1. The proliferation of TGF-β1-induced LX-2 cells was determined with 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. The mRNA and protein expression of collagen type 1 α1 (Col1α1) and α-smooth muscle actin (α-SMA) were assayed with quantitative PCR (qPCR) and Western blot (WB), respectively.

  Results  The expression vector pET28a/SUMO-tvNK1 was successfully obtained and the soluble SUMO-tvNK1 protein was induced after 5 hours of induction at 37℃ with 1 mM isopropyl-β-d-thiogalactoside (IPTG) and purified with Ni²⁺-affinity chromatograph. The molecular weight of the purified tvNK1 is 22.0 kilodalton based on the result of sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The results of MTT assay, qPCR and WB demonstrated that at the concentration of 20 and 40 ng/ml, the recombinant tvNK1 could obviously inhibit the proliferation of TGF-β1-induced LX-2 cells and reduce the mRNA and protein expression of Col1α1 and α-SMA in TGF-β1-induced LX-2 cells.

  Conclusion  The recombinant tvNK1 protein was obtained with a SUMO fusion procedure and the prepared tvNK1 can inhibit the proliferation TGF-β1-induced LX-2 cells and is of anti-fibrotic activity. These findings provide a basis for further in vitro researches.