Screening of an anti-inflammatory peptide from Hydrophis cyanocinctus and analysis of its activities and mechanism in DSS-induced acute colitis

Snake has been used for centuries as a traditional Chinese medicine, especially for therapeutic treatment for inflammatory diseases; however, its mechanisms of action and active constituents remain controversial. In our study, a tumor necrosis factor receptor 1 (TNFR1) selective binding peptide, Hydrostatin-SN1 (H-SN1), which was screened from a Hydrophis cyanocinctus venom gland T7 phage display library, was shown to exhibit significant anti-inflammatory activity in vitro and in vivo. As a TNFR1 antagonist, it reduced cytotoxicity mediated by TNF-alpha in L929 fibroblasts and effectively inhibited the combination between TNF-alpha with TNFR1 in surface plasmon resonance analysis. H-SN1 was also shown to suppress TNFR1-associated signaling pathways as it minimized TNF-alpha-induced NF-kappa B and MAPK activation in HEK293 embryonic kidney and HT29 adenocarcinoma cell lines. We next determined the effect of H-SN1 in vivo using a murine model of acute colitis induced by dextran sodium sulfate, demonstrating that H-SN1 lowered the clinical parameters of acute colitis including the disease activity index and histologic scores. H-SN1 also inhibited TNF/TNFR1 downstream targets at both mRNA and protein levels. These results indicate that H-SN1 might represent a suitable candidate for use in the treatment of TNF-alpha-associated inflammatory diseases such as inflammatory bowel diseases.