Counter-ion effect on antistaphylococcal activity and cytotoxicity of selected antimicrobial peptides

Abstract

In view of an appreciable increase in resistance of Staphylococcus aureus to the conventional antibiotics, it is desired to develop new effective drugs. Antimicrobial peptides (AMPs) seem to be attractive candidates. In general, AMPs samples used for in vitro studies consist of a peptide, counter-ion, and water. The presence of the counter-ion could be significant as it affects peptide secondary structure and biological activity. The purpose of this study was to estimate the impact of counter-ion on antistaphylococcal activity of selected AMPs (CAMEL, citropin 1.1, LL-37, pexiganan, temporin A). To do this, three kinds of salts were prepared, namely, acetates, hydrochlorides, and trifluoroacetates. In addition, the hemolytic activity against human red blood cells (hRBCs) and cytotoxicity (HaCaT) were determined. The results indicate that there is a substantial difference between different salts, but the pattern is not consistent for the peptides. In general, the antistaphylococcal activity decreased in the order: CAMEL > temporin A > pexiganan > citropin 1.1 ≫ LL-37. The highest selectivity indexes were determined for CAMEL hydrochloride, pexiganan acetate, and temporin A trifluoroacetate. This study shows how important is to take into account the kind of counter-ions when designing novel peptide-based antimicrobials.

Ultrashort Cationic Lipopeptides–Effect of N-Terminal Amino Acid and Fatty Acid Type on Antimicrobial Activity and Hemolysis

“…The hemolysis assay was performed as described earlier according to the method of Avrahami and Shai [53,54]. Fresh human red blood cells (hRBCs) with anticoagulant (EDTA) were rinsed three times with a PBS (Merck, Darmstadt, Germany) by centrifugation at 800× g for 10 min and resuspended in PBS.…”

“…with Met(47)(48)(49)(50), Met(O)(51)(52)(53)(54), and Met(O2)(55)(56)(57)(58) represent another series of compounds. However, this one differs in the number of oxygen atoms in the side chain (0, 1, and 2, respectively).…”

Rose Bengal-Mediated Photoinactivation of Multidrug Resistant Pseudomonas aeruginosa Is Enhanced in the Presence of Antimicrobial Peptides

“…Therefore, we checked how the treatment with RB and/or PEX affects the membrane of erythrocytes. The hemolytic behavior of PEX is similar to that of CAM so we omitted the latter from the experiment ( Sikora et al, 2018 ). As it is clearly shown, in dark conditions membranes stay intact for the time of the experiment.…”

“…Peptides: CAMEL (CAM; KWKLFKKIGAVLKVL-NH 2 ) and pexiganan (PEX, GIGKFLKKAKKFGKAFVKILKK-NH 2 ) were synthesized by solid-phase method using Fmoc (9-fluorenylmethyloxycarbonyl) chemistry on a Polystyrene Amide AM-RAM resin as described previously ( Sikora et al, 2018 ). The peptides were purified by Reverse-Phase High-Performance Liquid Chromatography (RP-HPLC), and then freeze-dried.…”

The Analogs of Temporin-GHa Exhibit a Broader Spectrum of Antimicrobial Activity and a Stronger Antibiofilm Potential against Staphylococcus aureus

“…Most AMPs used for in vitro studies are chemically synthesized, which contain peptide, counter-ion, and water. The peptide secondary structure and antimicrobial activity might be influenced by the different counter-ions [29]. The peptide salt of trifuoroacetate (TFA) showed slightly less antimicrobial activity than acetate or chloride salts.…”