title: Antifungal activity of novel synthetic peptides by accumulation of reactive oxygen species (ROS) and disruption of cell wall against Candida albicans.
abstract: In the present work, we investigated the antifungal activity of two de novo designed, antimicrobial peptides VS2 and VS3, incorporating unnatural amino acid α,β-dehydrophenylalanine (ΔPhe). We observed that the low-hemolytic peptides could irreversibly inhibit the growth of various Candida species and multidrug resistance strains at MIC(80) values ranging from 15.62 μM to 250 μM. Synergy experiments showed that MIC(80) of the peptides was drastically reduced in combination with an antifungal drug fluconazole. The dye PI uptake assay was used to demonstrate peptide induced cell membrane permeabilization. Intracellular localization of the FITC-labeled peptides in Candida albicans was studied by confocal microscopy and FACS. Killing kinetics, PI uptake assay, and the intracellular presence of FITC-peptides suggested that growth inhibition is not solely a consequence of increased membrane permeabilization. We showed that entry of the peptide in Candida cells resulted in accumulation of reactive oxygen species (ROS) leading to cell necrosis. Morphological alteration in Candida cells caused by the peptides was visualized by electron microscopy. We propose that de novo designed VS2 and VS3 peptides have multiple detrimental effects on target fungi, which ultimately result in cell wall disruption and killing. Therefore, these peptides represent a good template for further design and development as antifungal agents.
authors.affiliation: Membrane Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
authors.forename: Indresh Kumar
authors.initials: IK
authors.lastname: Maurya
authors.forename: Sarika
authors.initials: S
authors.lastname: Pathak
authors.forename: Monika
authors.initials: M
authors.lastname: Sharma
authors.forename: Hina
authors.initials: H
authors.lastname: Sanwal
authors.forename: Preeti
authors.initials: P
authors.lastname: Chaudhary
authors.forename: Santosh
authors.initials: S
authors.lastname: Tupe
authors.forename: Mukund
authors.initials: M
authors.lastname: Deshpande
authors.forename: Virander Singh
authors.initials: VS
authors.lastname: Chauhan
authors.forename: Rajendra
authors.initials: R
authors.lastname: Prasad
mesh_terms: D000935:Antifungal Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects* / Q000254:growth & development; D002473:Cell Wall / Q000187:drug effects* / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D000935:Antifungal Agents; D009842:Oligopeptides; D010455:Peptides; D017382:Reactive Oxygen Species