Enhanced cell selectivity of hybrid peptides with potential antimicrobial activity and immunomodulatory effect

• Published in: Biochimica et biophysica acta. General subjects Vol. 1864; no. 4; p. 129532
• Main Authors: Miao, Xiaokang, Zhou, Tianxiong, Zhang, Jingying, Xu, Jingjie, Guo, Xiaomin, Hu, Hui, Zhang, Xiaowei, Hu, Mingning, Li, Jingyi, Yang, Wenle, Xie, Junqiu, Xu, Zhaoqing, Mou, Lingyun
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.04.2020
• Subjects: anti-infective agents; antibacterial properties; Antimicrobial peptide; calcium; cell membranes; Cell selectivity; circular dichroism spectroscopy; cytotoxicity; drug resistance; Gram-negative bacteria; Hybridization; image analysis; Immunomodulation; immunomodulators; KFA3; macrophages; membrane permeability; mice; mitogen-activated protein kinase; phosphorylation; Substance P; transcription factor NF-kappa B; tumor necrosis factor-alpha; CD; IM; Substance P; Immunomodulation; Cell selectivity; Hybridization; NPN; KFA3; TFE; ONPG; mRBC; NK1; OD; OM; Antimicrobial peptide
• ISSN: 0304-4165; 1872-8006; 1872-8006
• DOI: 10.1016/j.bbagen.2020.129532

Hybridization is a useful strategy to bond the advantages of different peptides into novel constructions. We designed a series of AMPs based on the structures of a synthetic AMP KFA3 and a naturally-occurred host defense peptide substance P (SP) to obtain peptides retaining the high antibacterial activity of KFA3 and the immunomodulatory activity and low cytotoxicity of SP. Two repeats of KFA and different C terminal fragments of SP were hybridized, generating a series of novel AMPs (KFSP1–8). The antibacterial activities, host cell toxicity and immunomodulation were measured. The antibacterial mechanisms were investigated. Hybrid peptides KFSP1–4 exerted substantial antibacterial activities against Gram-negative bacteria of standard strains and clinical drug-resistant isolates including E.coli, A.baumannii and P.aeruginosa, while showing little toxicity towards host cells. Compared with KFA3, moderate reduction in α-helix content and the interruption in α-helix continuality were indicated in CD spectra analysis and secondary-structure simulation in these peptides. Membrane permeabilization combined with time-kill studies and FITC-labeled imaging, indicated a selective membrane interaction of KFSP1 with bacteria cell membranes. By specially activating NK1 receptor, the hybrid peptides kept the ability of SP to induce intracellular calcium release and ERK1/2 phosphorylation, but unable to stimulate NF-κB phosphorylation. KFSP1 facilitated the survival of mouse macrophage RAW264.7, directly interacting with LPS and inhibiting the LPS-induced NF-κB phosphorylation and TNF-α expression. Hybridization is a useful strategy to bond the advantages of different peptides. KFSP1 and its analogs are worth of advanced efforts to explore their potential applications as novel antimicrobial agents. •Design and synthesis of a novel class of AMP by hybridizing KFA3 and SP fragments•KFSP1 shows potent inhibitory effect on Gram-negative bacteria but little cytotoxicity against host cells.•KFSP1 preferentially disrupts bacteria cell membranes but not mammalian cell membrane.•KFSP1 directly binds LPS and inhibits proinflammatory cytokines expression.•KFSP1 activates NK1 receptor in mouse macrophage RAW264.7 and facilitates cell survival.