Influence of Different Cell-Penetrating Peptides on the Antimicrobial Efficiency of PNAs in Streptococcus pyogenes

Abstract

Streptococcus pyogenes is an exclusively human pathogen causing a wide range of clinical manifestations from mild superficial infections to severe, life-threatening, invasive diseases. S. pyogenes is consistently susceptible toward penicillin, but therapeutic failure of penicillin treatment has been reported frequently. At the same time, streptococcal resistance to alternative antibiotics, e.g., macrolides, is common. To reduce the application of antibiotics for treatment of S. pyogenes infections, it is mandatory to develop novel therapeutic strategies. Antisense peptide nucleic acids (PNAs) are synthetic DNA derivatives widely applied for hybridization-based microbial diagnostics. They have a high potential as therapeutic agents, because PNA antisense targeting of essential genes was shown to reduce growth of several pathogenic bacterial species. Spontaneous cellular uptake of PNAs is restricted in eukaryotes and in bacteria. To overcome this problem, PNAs can be coupled to cell-penetrating peptides (CPPs) that support PNA translocation over the cell membrane. In bacteria, the efficiency of CPP-mediated PNA uptake is species specific. Previously, HIV-1 transactivator of transcription (HIV-1 TAT) peptide-coupled anti-gyrA PNA was shown to inhibit growth of S. pyogenes. Here, we investigate the effect of 18 CPP-coupled anti-gyrA PNAs on S. pyogenes growth and virulence. HIV-1 TAT, oligolysine (K8), and (RXR)4XB peptide-coupled anti-gyrA PNAs efficiently abolished bacterial growth in vitro. Consistently, treatment with these three CPP-PNAs increased survival of larvae in a Galleria mellonella infection model.

An RNA biology perspective on species‐specific programmable RNA antibiotics

“…More importantly, different peptides penetrate different bacteria with different efficiencies, as nicely illustrated by the clear differences seen between Burkholderia versus Pseudomonas and Acinetobacter (Geller et al, 2013;Greenberg et al, 2010;Howard et al, 2017). As can be expected from their generally different envelope structures, some peptides seem to work better in Gram-positive than Gram-negative species (see a recent discussion in (Barkowsky et al, 2019)). Together, this argues that species specificity in killing in complex communities can be improved by using the most selective peptide for the bacterium to be targeted.…”

“…tions, suggesting that they may be therapeutically useful for treating sepsis or different diseases of the lung (Barkowsky et al, 2019;Daly et al, 2018;Geller et al, 2018;Sully & Geller, 2016).…”

“…The published work spans Gram‐negative Acinetobacter , Brucella, Burkholderia, Campylobacter, Haemophilus, Klebsiella, Pseudomonas, and Salmonella species, and Gram‐positive Enterococcus , Listeria, Staphylococcus and Streptococcus species (Geller et al, ; Sully & Geller, ). ASOs have shown efficacy in different experimental mouse infections, suggesting that they may be therapeutically useful for treating sepsis or different diseases of the lung (Barkowsky et al, ; Daly et al, ; Geller et al, ; Sully & Geller, ).…”

Recent progress of bacterial FtsZ inhibitors with a focus on peptides

“…Cell‐penetrating peptides (CPPs), consisting of positively charged residues, can deliver PNA into cells [72]. Among CPPs, peptide (RXR) 4 XB is most widely applied in bacteria to improve the entry of PNAs and inhibit gene expression and cell growth [75,76]. Liang et al designed (RXR) 4 XB‐conjugated PNAs targeting FtsZ, including PPNA1 (targeting 309–323 nucleotides of ftsZ gene) and PPNA2 (targeting the translation initiation and ribosomal‐binding sites of ftsZ ), could inhibit the growth of MRSA in vitro by the downregulation of ftsZ gene expression in a dose‐dependent manner [75].…”

“…bacteria such as E. coli and S. aureus[74,76,78,79]. Ghosal et al constructed the L-or D-type (KFF) 3 K-PNA conjugates targeting ftsZ and acpP genes and identified D-type (KFF) 3 K-PNA-resistant mutants in E. coli (deletion of sbmA)[74].…”