N1-acetyl substituted pyrrolidine derivative CIP-A5: A novel compound that could ameliorate liver cirrhosis through modulation of hepatic stellate cell activity

(2S,4R)-methyl 1-acetyl-4-(N-(4-bromophenyl)sulfamoyloxy)pyrrolidine-2-carboxylate (CIP-A5) is the N1-acetyl substituted pyrrolidine derivative which was designed against the structure of matrix metalloproteinase (MMP-2) and MMP-9. CIP-A5 has been considered as a candidate compound for treatment of liver cirrhosis. In this study, we evaluated the efficacy of CIP-A5 on the activity of hepatic stellate cells. CIP-A5 prevented the transforming growth factor β (TGF-β)-induced proliferation of hepatic stellate HSC-T6 cells as estimated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. CIP-A5 stimulated MMPs activity as evidenced by an increase of degradation of succinylated gelatin. Gelatin zymography analysis showed that CIP-A5 stimulated the secretion and activity of MMP-2 and MMP-9 in HSC-T6 cells. This stimulatory effect on MMPs was verified by the observation of increased expression of MMP-2 and MMP-9 as evaluated by Western blot assay. At the same time, a significant decrease of the expression of tissue inhibitors of matrix metalloproteinases-1 (TIMP-1) was observed, suggesting a modulation of the balance of MMPs/TIMPs in hepatic stellate cells. CIP-A5 treatment also resulted in suppression of the profibrogenic cytokines, such as TGF-β, tumor necrosis factor alpha (TNF-α) and connective tissue growth factor (CTGF) in HSC-T6 cells. CIP-A5 did not have cytotoxicity to human normal hepatic cells. These results implied that CIP-A5 could selectively ameliorate the process of liver cirrhosis through modulation of activated hepatic stellate cell activity, which offers hope for prevention and treatment of this devastating end-stage liver disease.