Lysine Stapling Screening Provides Stable and Low Toxic Cationic Antimicrobial Peptides Combating Multidrug-Resistant Bacteria In Vitro and In Vivo

Abstract

Cationic antimicrobial peptides (CAMPs) are promising for treatment of multidrug-resistant (MDR) bacteria-caused infections. However, clinical application of CAMPs has been hampered mostly due to their poor proteolytic stability and hemolytic toxicity. Recently, lysine-stapled CAMPs developed by us had been proved to increase peptide stability in vitro without induction of hemolysis. Herein, the applicability of the lysine stapling strategy was further explored by using five natural or artificial CAMPs as model peptides. Lysine stapling screening was implemented to provide 13 cyclic analogues in total. Biological screening of these cyclic analogues showed that CAMPs with a better amphiphilic structure were inclined to exhibit improved antimicrobial activity, protease stability, and biocompatibility after lysine-stapling. One of the stapled analogues of BF15-a1 was found to have extended half-life in plasma, enhanced antimicrobial activity against clinically isolated MDR ESKAPE pathogens, and remained highly effective in combating MRSA infection in a mouse model.

In Silico Design and Synthesis of Antifungal Peptides Guided by Quantitative Antifungal Activity

“…As a preliminary overview of the peptides to be designed, the physicochemical properties, including amino acid composition, sequence length, and AFI distribution, were calculated, as depicted in Figure . The amino acid composition (Figure A) revealed a predominance of arginine, leucine, and lysine, which is consistent with previous reports highlighting the prevalence of positively charged amino acids in AFPs. − Figure B illustrates the distributions of sequence length and AFI, with most sequence lengths falling within the ranges of 20–25 and 35–40 residues. The majority of AFI is in the range of 3.00–5.00 μM, and only four sequences possess AFI smaller than 3.00 μM.…”

Identification of Three Campylobacter Lysins and Enhancement of Their Anti-Escherichia coli Efficacy Using Colicin-Based Translocation and Receptor-Binding Domain Fusion

“…Briers et al combined a polycationic nonapeptide (PCNP) with endolysin, which killed several multidrug-resistant strains in vitro with a 4- to 5-log reduction within 30 min ( 39 ). Similarly, Hu et al not only verified this type of CAP function but also discovered that artilysin remained highly effective in a mouse infection model ( 64 ). We also developed PCNP-Clysins based on previous findings.…”

A guided tour through α-helical peptide antibiotics and their targets

“…As proteases require their peptide substrates to be in an extended conformation for efficient cleavage [228], a stable α-helical structure may increase the resistance to enzymatic proteolysis. Indeed, stapled αAMPs have been shown to be highly resistant to proteolytic degradation [226,227,229], which provided the basis for efficacy in animal infection models [226,229]. A bicyclic stapling approach has been reported, tethering three lysine residues positioned at i, (i + 4) and (i + 8) [230].…”