Mammalian cell toxicity and candidacidal mechanism of Arg- or Lys-containing Trp-rich model antimicrobial peptides and their d-enantiomeric peptides.
In this study, we investigated the mammalian cell toxicity and candidacidal mechanism of Arg- or Lys-containing Trp-rich model antimicrobial peptides (K(6)L(2)W(3) and R(6)L(2)W(3)) and their d-enantiomeric peptides (K(6)L(2)W(3)-d and R(6)L(2)W(3)-d). Arg-containing peptides were more toxic to human erythrocytes and mammalian cells as compared to Lys-containing peptides. Arg-containing peptides is slightly more hydrophobic than Lys-containing counterparts, as judged from their reverse phase-high performance liquid chromatography (RP-HPLC) retention time. These results suggested that a little difference in hydrophobicity of these peptides affect their hemolytic activity and mammalian cell toxicity. Interestingly, K(6)L(2)W(3) and K(6)L(2)W(3)-d almost similar mammalian cell cytotoxicity, whereas R(6)L(2)W(3)-d showed much higher cytotoxicity as compared to R(6)L(2)W(3). A low ability to facilitate fluorescent marker escape from Candida albicans membrane-mimicking vesicles suggested that the major target site of Lys-containing peptides may be not the cell membrane but the cytoplasm of C. albicans. Confocal laser-scanning microscopy revealed that FITC-labeled Lys-containing peptides penetrated the cell wall and cell membrane and accumulated inside the cells, whereas FITC-labeled Arg-containing peptides did not penetrate but associated with the membranes. Collectively, our results suggested that the ultimate target site of action of Arg-containing peptides and Lys-containing peptides may be the membrane and the cytoplasm of C. albicans, respectively.
Nan
Yong Hai
YH
Department of Bio-Materials, Graduate School, Chosun University, Gwangju 501-759, Republic of Korea.
Lee
Sung Haeng
SH
Kim
Hak Jun
HJ
Shin
Song Yub
SY
D000818:Animals; D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology; D001120:Arginine / Q000378:metabolism; D002176:Candida albicans / Q000187:drug effects*; D006461:Hemolysis / Q000187:drug effects*; D006801:Humans; D008239:Lysine / Q000378:metabolism; D051379:Mice; D008826:Microbial Sensitivity Tests; D041681:NIH 3T3 Cells; D013237:Stereoisomerism; D014364:Tryptophan / Q000378:metabolism
D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D014364:Tryptophan; D001120:Arginine; D008239:Lysine