Enhancing the Antimicrobial Properties of Peptides through Cell-Penetrating Peptide Conjugation: A Comprehensive Assessment

Abstract

Combining antimicrobial peptides (AMPs) with cell-penetrating peptides (CPPs) has shown promise in boosting antimicrobial potency, especially against Gram-negative bacteria. We examined the CPP-AMP interaction with distinct bacterial types based on cell wall differences. Our investigation focused on AMPs incorporating penetratin CPP and dihybrid peptides containing both cell-penetrating TAT protein fragments from the human immunodeficiency virus and Antennapedia peptide (Antp). Assessment of the peptides TAT-AMP, AMP-Antp, and TAT-AMP-Antp revealed their potential against Gram-positive strains (Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus (MRSA), and Bacillus cereus). Peptides TAT-AMP and AMP-Antp using an amyloidogenic AMP from S1 ribosomal protein Thermus thermophilus, at concentrations ranging from 3 to 12 μM, exhibited enhanced antimicrobial activity against B. cereus. TAT-AMP and TAT-AMP-Antp, using an amyloidogenic AMP from the S1 ribosomal protein Pseudomonas aeruginosa, at a concentration of 12 µM, demonstrated potent antimicrobial activity against S. aureus and MRSA. Notably, the TAT-AMP, at a concentration of 12 µM, effectively inhibited Escherichia coli (E. coli) growth and displayed antimicrobial effects similar to gentamicin after 15 h of incubation. Peptide characteristics determined antimicrobial activity against diverse strains. The study highlights the intricate relationship between peptide properties and antimicrobial potential. Mechanisms of AMP action are closely tied to bacterial cell wall attributes. Peptides with the TAT fragment exhibited enhanced antimicrobial activity against S. aureus, MRSA, and P. aeruginosa. Peptides containing only the Antp fragment displayed lower activity. None of the investigated peptides demonstrated cytotoxic or cytostatic effects on either BT-474 cells or human skin fibroblasts. In conclusion, CPP-AMPs offer promise against various bacterial strains, offering insights for targeted antimicrobial development.

Killing of Plasmodium Sporozoites by Basic Amphipathic α-Helical Fusion Peptides

“…Many of these stages develop inside a parasitophorous vacuole; translocation through two lipid membranes will be required to directly reach the parasite membrane. The addition of CPP to AMPs is known to increase their antimicrobial activity, mainly against Gram-negative bacteria [ 48 , 49 ]. However, RT39 does not seem to translocate into sporozoites, the addition of CPP to AAC11-derived peptides or other AMPs could improve the killing efficacy of intracellular and extracellular plasmodial stages in vivo.…”

Optimizing Antimicrobial Peptide Design: Integration of Cell-Penetrating Peptides, Amyloidogenic Fragments, and Amino Acid Residue Modifications

“…Moreover, peptides containing the TAT fragment exhibited greater efficacy in inhibiting bacterial growth compared to those containing only the Antp penetration peptide fragment. This was demonstrated in our recent article, where we tested peptides based on the amyloidogenic region of the S1 ribosomal protein of P. aeruginosa [ 62 ]. Notably, peptide R44K S * displayed the most potent antimicrobial activity against a wide range of microorganisms, but also exhibited higher toxicity towards human cells.…”

“…This is indicated by the observed data on step-like current fluctuations associated with the formation of ion-permeable transmembrane pores. Previously, Kravchenko et al showed that the synthetic R23I T peptide containing the TAT sequence (RKKRRQRRR) at the N-terminus of the amyloidogenic fragment caused the disruption of POPE:POPG bilayers at concentrations greater than 80 μg/mL [ 62 ]. The obtained difference in the concentrations of R23I T and R44K S peptides required for membrane breakdown might be explained by the additional CPP fragment (the antennapedia peptide fragment (SRQIKIWFQNRRMKWKK)) on the C-terminus of the amyloidogenic peptide of R44K S .…”

“…The obtained difference in the concentrations of R23I T and R44K S peptides required for membrane breakdown might be explained by the additional CPP fragment (the antennapedia peptide fragment (SRQIKIWFQNRRMKWKK)) on the C-terminus of the amyloidogenic peptide of R44K S . Probably, the presence of two CPP fragments enhances the membrane activity of R44K S compared to R23I T [ 62 ], and moreover R44K S , demonstrated greater antibacterial activity than R23I T .…”

“…After the incubation period, serum was added to the medium to a final concentration of 10%, and the preparation was added dropwise onto the cells. The cytotoxic effects of peptides against eukaryotic cells (human fibroblasts and BT474) were subsequently assessed using the same method as in the previous study [ 62 ].…”