“Metaphilic” Cell-Penetrating Polypeptide-Vancomycin Conjugate Efficiently Eradicates Intracellular Bacteria via a Dual Mechanism

Abstract

Infections by intracellular pathogens are difficult to treat because of the poor accessibility of antibiotics to the pathogens encased by host cell membranes. As such, a strategy that can improve the membrane permeability of antibiotics would significantly increase their efficiency against the intracellular pathogens. Here, we report the design of an adaptive, metaphilic cell-penetrating polypeptide (CPP)–antibiotic conjugate (VPP-G) that can effectively eradicate the intracellular bacteria both in vitro and in vivo . VPP-G was synthesized by attaching vancomycin to a highly membrane-penetrative guanidinium-functionalized metaphilic CPP. VPP-G effectively kills not only extracellular but also far more challenging intracellular pathogens, such as S. aureus , methicillin-resistant S. aureus , and vancomycin-resistant Enterococci . VPP-G enters the host cell via a unique metaphilic membrane penetration mechanism and kills intracellular bacteria through disruption of both cell wall biosynthesis and membrane integrity. This dual antimicrobial mechanism of VPP-G prevents bacteria from developing drug resistance and could also potentially kill dormant intracellular bacteria. VPP-G effectively eradicates MRSA in vivo , significantly outperforming vancomycin, which represents one of the most effective intracellular antibacterial agents reported so far. This strategy can be easily adapted to develop other conjugates against different intracellular pathogens by attaching different antibiotics to these highly membrane-penetrative metaphilic CPPs.

The multifaceted nature of antimicrobial peptides: current synthetic chemistry approaches and future directions

“…Finally, the authors used SEM to confirm that cell wall damage occurred when S. aureus cells were treated with VPP-G, confirming a dualmechanism of action wherein the AMPM caused membrane disruption, and vancomycin inhibited cell wall biosynthesis. 509 Novel and effective treatments are needed to treat infections caused by intracellular pathogens. It is promising that the use of AMPs in this field is growing, however, further research is required.…”

“…Vancomycin is shown in red, and a membrane disruptive AMPM is shown in blue. 509 antimicrobial activity that includes antifungal activity. However, many papers describing novel AMPs focus on their antibacterial properties and do not screen against fungal strains.…”

Membrane-disruptive peptides/peptidomimetics-based therapeutics: Promising systems to combat bacteria and cancer in the drug-resistant era

“…Compared with monotherapy, the combination of MDPs and other therapeutic drugs has been proposed as a promising strategy for the enhancement of bacterial or cancer therapy, via multiple mechanisms of action in the hopes of both achieving enhanced therapeutic efficacy and preventing bacteria from developing resistance 162 , 214 , 215 , 216 , 217 . Therefore, many different MDP-based co-delivery systems have been developed.…”

Antibiotic–cell‐penetrating peptide conjugates targeting challenging drug‐resistant and intracellular pathogenic bacteria

“…Blue: Hoechst; yellow: CellMask; red: Cy5‐VPP‐G. Reprinted (adapted) with permission (Jiang et al., 2020) Copyright (2020), American Chemical Society. (d) Structure of V V ‐R 3 C‐C 12 .…”

“…Recently, the CPP PP‐G has been conjugated to vancomycin (Jiang et al., 2020). PP‐G is a flexible guanidinium‐rich polypeptide with enhanced cell penetration as compared to Tat and oligo‐arginine CPPs, but with no activity against intracellular bacteria.…”