title: C. albicans growth, transition, biofilm formation, and gene expression modulation by antimicrobial decapeptide KSL-W.
abstract: BACKGROUND
  Antimicrobial peptides have been the focus of much research over the last decade because of their effectiveness and broad-spectrum activity against microbial pathogens. These peptides also participate in inflammation and the innate host defense system by modulating the immune function that promotes immune cell adhesion and migration as well as the respiratory burst, which makes them even more attractive as therapeutic agents. This has led to the synthesis of various antimicrobial peptides, including KSL-W (KKVVFWVKFK-NH2), for potential clinical use. Because this peptide displays antimicrobial activity against bacteria, we sought to determine its antifungal effect on C. albicans. Growth, hyphal form, biofilm formation, and degradation were thus examined along with EFG1, NRG1, EAP1, HWP1, and SAP 2-4-5-6 gene expression by quantitative RT-PCR.
  
  
  RESULTS
  This study demonstrates that KSL-W markedly reduced C. albicans growth at both early and late incubation times. The significant effect of KSL-W on C. albicans growth was observed beginning at 10 μg/ml after 5 h of contact by reducing C. albicans transition and at 25 μg/ml by completely inhibiting C. albicans transition. Cultured C. albicans under biofilm-inducing conditions revealed that both KSL-W and amphotericin B significantly decreased biofilm formation at 2, 4, and 6 days of culture. KSL-W also disrupted mature C. albicans biofilms. The effect of KSL-W on C. albicans growth, transition, and biofilm formation/disruption may thus occur through gene modulation, as the expression of various genes involved in C. albicans growth, transition and biofilm formation were all downregulated when C. albicans was treated with KSL-W. The effect was greater when C. albicans was cultured under hyphae-inducing conditions.
  
  
  CONCLUSIONS
  These data provide new insight into the efficacy of KSL-W against C. albicans and its potential use as an antifungal therapy.
authors.forename: Simon
authors.initials: S
authors.lastname: Theberge
authors.forename: Abdelhabib
authors.initials: A
authors.lastname: Semlali
authors.forename: Abdullah
authors.initials: A
authors.lastname: Alamri
authors.forename: Kai P
authors.initials: KP
authors.lastname: Leung
authors.affiliation: Oral Ecology Research Group, Faculty of Dentistry, Laval University, 2420, rue de la Terrasse, Quebec G1V 0A6, QC, Canada. mahmoud.rouabhia@fmd.ulaval.ca.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Rouabhia
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D002176:Candida albicans / Q000187:drug effects* / Q000502:physiology*; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects*; D025301:Hyphae / Q000187:drug effects* / Q000254:growth & development; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; C554541:lysyl-lysyl-valyl-valyl-phenylalanyl-tryptophyl-valyl-lysyl-phenylalanyl-lysine