青环海蛇抗菌肽Hc-CATH的分子设计及药效毒理优化

Molecular design, pharmacology and toxicology optimization of antimicrobial peptide from Hydrophis cyanocinctus, Hc-CATH

摘要:

为获得分子量小、毒性低的抗感染多肽药物先导分子，以来源于青环海蛇的cathelicidin家族抗菌肽Hc-CATH为模板，设计了长度分别为16和15个氨基酸残基的改造体Hc-16和Hc-15，并通过CCK8实验、最小抑菌浓度 (Minimal inhibitory concentration，MIC) 实验、ELISA实验和生物膜干涉技术 (Bio-layer interferometry，BLI)，对其进行毒性、抗菌活性、抗炎活性及LPS中和活性筛选。结果显示，两种改造体中，Hc-16对包括临床耐药菌在内的病原体具有广谱抗菌活性，最小抑菌浓度仅为4.69 μg/mL。同时抑制了LPS诱导的炎症因子TNF-α、IL-6的表达，显著降低感染诱发的炎症反应及细胞毒性。此外，构效关系研究表明C-、N-两端的苯丙氨酸在Hc-16抗菌抗炎活性中起着至关重要的作用。综上，Hc-16改造肽相比原模板具有更高的抗菌抗炎活性、更低的毒性以及更小的分子量，因而具有成本低、更好的成药性优势和较好的临床应用价值。

Abstract:

Based on the cathelicidin family antimicrobial peptide Hc-CATH derived from sea snake, the Hc-16 and Hc-15 of 16 and 15 amino acid residues, were designed. By using CCK8, minimal inhibitory concentration, ELISA and bio-layer interferometry assays, their cytotoxicity, antibacterial activity, anti-inflammatory activity, and LPS neutralization activity was examined. Compared with Hc-15, Hc-16 had lower cytotoxicity and better broad-spectrum antibacterial activity against pathogens including clinically resistant bacteria, with the minimum inhibitory concentration of only 4.69 μg/mL. Hc-16 inhibited the expression of inflammatory cytokines of TNF-α and IL-6 induced by LPS, so as to significantly reduce the inflammatory response induced by infection. In addition, structure-activity relationship studies have shown that the phenylalanine at the C- and N-terminals of Hc-16 played a crucial role in its antibacterial and anti-inflammatory activity. Altogether, the designed Hc-16 has an excellent prospect to be developed into a novel antibiotic.