A novel, rationally designed, hybrid antimicrobial peptide, inspired by cathelicidin and aurein, exhibits membrane-active mechanisms against Pseudomonas aeruginosa

Natthaporn Klubthawee,Poom Adisakwattana,Warunee Hanpithakpong,Ratchaneewan Aunpad,Sangdao Somsri

doi:10.1038/s41598-020-65688-5

A novel, rationally designed, hybrid antimicrobial peptide, inspired by cathelicidin and aurein, exhibits membrane-active mechanisms against Pseudomonas aeruginosa

Natthaporn Klubthawee, Poom Adisakwattana + Show 3 more

Open Access

https://doi.org/10.1038/s41598-020-65688-5

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Abstract

Antimicrobial peptides (AMPs) are promising alternatives to classical antibiotics for the treatment of drug-resistant infections. Due to their versatility and unlimited sequence space, AMPs can be rationally designed by modulating physicochemical determinants to favor desired biological parameters and turned into novel therapeutics. In this study, we utilized key structural and physicochemical parameters, in combination with rational engineering, to design novel short α-helical hybrid peptides inspired by the well-known natural peptides, cathelicidin and aurein. By comparing homologous sequences and abstracting the conserved residue type, sequence templates of cathelicidin (P0) and aurein (A0) were obtained. Two peptide derivatives, P7 and A3, were generated by amino acid substitution based on their residue composition and distribution. In order to enhance antimicrobial activity, a hybrid analog of P7A3 was designed. The results demonstrated that P7A3 had higher antibacterial activity than the parental peptides with unexpectedly high hemolytic activity. Strikingly, C-terminal truncation of hybrid peptides containing only the α-helical segment (PA-18) and shorter derivatives confer potent antimicrobial activity with reduced hemolytic activity in a length‐dependent manner. Among all, PA-13, showed remarkable broad-spectrum antibacterial activity, especially against Pseudomonas aeruginosa with no toxicity. PA-13 maintained antimicrobial activity in the presence of physiological salts and displayed rapid binding and penetration activity which resulted in membrane depolarization and permeabilization. Moreover, PA-13 showed an anti-inflammatory response via lipopolysaccharide (LPS) neutralization with dose-dependent, inhibiting, LPS-mediated Toll-like receptor activation. This study revealed the therapeutic potency of a novel hybrid peptide, and supports the use of rational design in development of new antibacterial agents.

Highlights

Antimicrobial peptides (AMPs) are promising alternatives to classical antibiotics for the treatment of drug-resistant infections
To identify www.nature.com/scientificreports the shortest amino acid sequence needed for potent antimicrobial activity and reduced cytotoxicity, a series of truncated derivatives were designed by truncating amino acids at the C-terminal end of P7A3
The emergence in pathogenic bacteria of resistance to conventional antibiotics has become a serious threat to public health

Summary

Introduction

Antimicrobial peptides (AMPs) are promising alternatives to classical antibiotics for the treatment of drug-resistant infections. Antimicrobial peptides (AMPs) are an essential component of the innate immune system produced as a first line of defense by all multicellular organisms[3] With such exceptional properties as broad-spectrum antimicrobial activity, rapid action and infrequent development of resistance[4,5], AMP-based pharmaceuticals provide excellent templates for a wide range of antimicrobial agents and biomedical applications. Optimization of sequences or modification of AMPs can improve antimicrobial effects while reducing cytotoxicity and so overcome barriers and expedite development for clinical application[7,18,19,20] Due to their versatility and unlimited sequence space, AMPs can be rationally designed by modulating physicochemical determinants to favor the desired biological parameters and turned into novel therapeutics. Modification of the hybrid peptide of cecropin A and LL-37 improves the therapeutic index[23]

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