title: Comparative Ploidy Proteomics of Candida albicans Biofilms Unraveled the Role of the AHP1 Gene in the Biofilm Persistence Against Amphotericin B.
abstract: Candida albicans is a major fungal pathogen causing lethal infections in immunocompromised patients. C. albicans forms antifungal tolerant biofilms contributing significantly to therapeutic failure. The recently established haploid C. albicans biofilm model provides a new toolbox to uncover the mechanism governing the higher antifungal tolerance of biofilms. Here, we comprehensively examined the proteomics and antifungal susceptibility of standard diploid (SC5314 and BWP17) and stable haploid (GZY792 and GZY803) strains of C. albicans biofilms. Subsequent downstream analyses identified alkyl hydroperoxide reductase 1 (AHP1) as a critical determinant of C. albicans biofilm's tolerance of amphotericin B. At 32 μg/ml of amphotericin B, GZY803 haploid biofilms showed 0.1% of persister population as compared with 1% of the diploid biofilms. AHP1 expression was found to be lower in GZY803 biofilms, and AHP1 overexpression in GZY803 restored the percentage of persister population. Consistently, deleting AHP1 in the diploid strain BWP17 caused a similar increase in amphotericin B susceptibility. AHP1 expression was also positively correlated with the antioxidant potential. Furthermore, C. albicans ira2Δ/Δ biofilms were susceptible to amphotericin B and had a diminished antioxidant capacity. Interestingly, AHP1 overexpression in the ira2Δ/Δ strain restored the antioxidant potential and enhanced the persister population against amphotericin B, and shutting down the AHP1 expression in ira2Δ/Δ biofilms reversed the effect. In conclusion, we provide evidence that the AHP1 gene critically determines the amphotericin B tolerance of C. albicans biofilms possibly by maintaining the persisters' antioxidant capacity. This finding will open up new avenues for developing therapies targeting the persister population of C. albicans biofilms. The mass spectrometry proteomics data are available via ProteomeXchange with identifier PXD004274.
authors.affiliation: From the ‡Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore 119083.
authors.forename: Thuyen
authors.identifier: 0000-0003-4172-3670
authors.initials: T
authors.lastname: Truong
authors.affiliation: the §Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Proteos, Singapore 138673, and.
authors.forename: Guisheng
authors.initials: G
authors.lastname: Zeng
authors.affiliation: the ¶Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543.
authors.forename: Lin
authors.initials: L
authors.lastname: Qingsong
authors.affiliation: the ¶Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543.
authors.forename: Lim Teck
authors.initials: LT
authors.lastname: Kwang
authors.affiliation: From the ‡Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore 119083.
authors.forename: Cao
authors.initials: C
authors.lastname: Tong
authors.affiliation: the §Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Proteos, Singapore 138673, and.
authors.forename: Fong Yee
authors.initials: FY
authors.lastname: Chan
authors.affiliation: the §Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Proteos, Singapore 138673, and jaya@nus.edu.sg mcbwangy@imcb.a-star.edu.sg.
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
authors.affiliation: From the ‡Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore 119083, jaya@nus.edu.sg mcbwangy@imcb.a-star.edu.sg.
authors.forename: Chaminda Jayampath
authors.initials: CJ
authors.lastname: Seneviratne
mesh_terms: D000666:Amphotericin B / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects; D002176:Candida albicans / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D004171:Diploidy; D015536:Down-Regulation; D024881:Drug Resistance, Bacterial; D005656:Fungal Proteins / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D054464:Peroxiredoxins / Q000378:metabolism*; D011123:Polyploidy; D040901:Proteomics / Q000379:methods
chemical_list: D000935:Antifungal Agents; D005656:Fungal Proteins; D000666:Amphotericin B; D054464:Peroxiredoxins