Functions of Candida albicans cell wall glycosidases Dfg5p and Dcw1p in biofilm formation and HOG MAPK pathway

Background Candida albicans is a commensal fungus that inhabits the oral mucosal surface and causes oral and systemic candidiasis. Oral candidiasis most commonly occurs in patients with AIDS, denture wearers and newborn children. Systemic candidiasis occurs mainly in immunocompromised patients and p...

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Main Authors: Ryan Mancuso, Jennifer Chinnici, Charlene Tsou, Sujay Busarajan, Raveena Munnangi, Abhiram Maddi
Format: Article
Language:English
Published: PeerJ Inc. 2018-09-01
Series:PeerJ
Subjects:
Online Access:https://peerj.com/articles/5685.pdf
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author Ryan Mancuso
Jennifer Chinnici
Charlene Tsou
Sujay Busarajan
Raveena Munnangi
Abhiram Maddi
author_facet Ryan Mancuso
Jennifer Chinnici
Charlene Tsou
Sujay Busarajan
Raveena Munnangi
Abhiram Maddi
author_sort Ryan Mancuso
collection DOAJ
description Background Candida albicans is a commensal fungus that inhabits the oral mucosal surface and causes oral and systemic candidiasis. Oral candidiasis most commonly occurs in patients with AIDS, denture wearers and newborn children. Systemic candidiasis occurs mainly in immunocompromised patients and patients admitted to hospitals for prolonged periods. C. albicans homologous genes, DFG5 and DCW1, encode for two closely related cell wall proteins with putative glycosyltransferase enzyme activity and C-terminal GPI-anchors. Past studies have shown that individual DFG5 and DCW1 mutations are viable but simultaneous deletion of DFG5 and DCW1 in C. albicans results in lethality. However, the exact functions of these cell wall based enzymes, which represent potential drug targets, are not understood. Methods C. albicans DFG5/DCW1 heterologous and conditional double mutant strains were assessed for growth and biofilm formation in comparison to wild type and parental strains. Cell wall and heat stress susceptibility of the mutant and control strains were assessed using agar spotting assays. Growth was assessed under normal and osmotic stress conditions along with light microscopy imaging. Biofilm dry weight and microscopic imaging analysis of biofilms was performed. Hypha formation in response to serum was analyzed using light microscopy imaging. Western blot analysis of mutant strains and control strains was performed to assess Hog1 basal levels and phosphorylation status. Results Analysis of the heterologous mutants indicated that Dfg5p is more important for growth while Dcw1p appeared to play a role in cell wall integrity response. The conditional double mutant was observed to be less resistant to cell wall stress. However, growth of the mutants was similar under control and osmotic stress conditions. The mutants were also able to grow similar to wild type under heat stress. Biofilm formation was reduced in the mutants where DFG5 was deleted or suppressed. Hyphal morphogenesis was reduced although germ tube formation was observed in the biofilms of the mutant strains. Basal Hog1 protein levels were reduced or absent in the DFG5 and DCW1 mutants. However, osmotic stress was able to induce Hog1 protein levels comparable to wild type. Hog1 phosphorylation appeared to be slightly reduced although not significantly. In addition to biofilm assays, serum dose response imaging analysis indicated that hyphae formation in DFG5 and DCW1 mutants was defective. Conclusions These data indicate that DFG5 and DCW1 are required for hyphal morphogenesis and biofilm formation in C. albicans. These functions may be regulated via basal Hog1 MAPK which is required for transcriptional regulation of chitin synthesis.
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spelling doaj.art-e4291b9464524fe8b83f3ada694782562023-12-03T11:18:46ZengPeerJ Inc.PeerJ2167-83592018-09-016e568510.7717/peerj.5685Functions of Candida albicans cell wall glycosidases Dfg5p and Dcw1p in biofilm formation and HOG MAPK pathwayRyan Mancuso0Jennifer Chinnici1Charlene Tsou2Sujay Busarajan3Raveena Munnangi4Abhiram Maddi5Periodontics & Endodontics, State University of New York at Buffalo, Buffalo, NY, United States of AmericaPeriodontics & Endodontics, State University of New York at Buffalo, Buffalo, NY, United States of AmericaPeriodontics & Endodontics, State University of New York at Buffalo, Buffalo, NY, United States of AmericaPeriodontics & Endodontics, State University of New York at Buffalo, Buffalo, NY, United States of AmericaPeriodontics & Endodontics, State University of New York at Buffalo, Buffalo, NY, United States of AmericaPeriodontics & Endodontics, Oral Biology, State University of New York at Buffalo, Buffalo, NY, United States of AmericaBackground Candida albicans is a commensal fungus that inhabits the oral mucosal surface and causes oral and systemic candidiasis. Oral candidiasis most commonly occurs in patients with AIDS, denture wearers and newborn children. Systemic candidiasis occurs mainly in immunocompromised patients and patients admitted to hospitals for prolonged periods. C. albicans homologous genes, DFG5 and DCW1, encode for two closely related cell wall proteins with putative glycosyltransferase enzyme activity and C-terminal GPI-anchors. Past studies have shown that individual DFG5 and DCW1 mutations are viable but simultaneous deletion of DFG5 and DCW1 in C. albicans results in lethality. However, the exact functions of these cell wall based enzymes, which represent potential drug targets, are not understood. Methods C. albicans DFG5/DCW1 heterologous and conditional double mutant strains were assessed for growth and biofilm formation in comparison to wild type and parental strains. Cell wall and heat stress susceptibility of the mutant and control strains were assessed using agar spotting assays. Growth was assessed under normal and osmotic stress conditions along with light microscopy imaging. Biofilm dry weight and microscopic imaging analysis of biofilms was performed. Hypha formation in response to serum was analyzed using light microscopy imaging. Western blot analysis of mutant strains and control strains was performed to assess Hog1 basal levels and phosphorylation status. Results Analysis of the heterologous mutants indicated that Dfg5p is more important for growth while Dcw1p appeared to play a role in cell wall integrity response. The conditional double mutant was observed to be less resistant to cell wall stress. However, growth of the mutants was similar under control and osmotic stress conditions. The mutants were also able to grow similar to wild type under heat stress. Biofilm formation was reduced in the mutants where DFG5 was deleted or suppressed. Hyphal morphogenesis was reduced although germ tube formation was observed in the biofilms of the mutant strains. Basal Hog1 protein levels were reduced or absent in the DFG5 and DCW1 mutants. However, osmotic stress was able to induce Hog1 protein levels comparable to wild type. Hog1 phosphorylation appeared to be slightly reduced although not significantly. In addition to biofilm assays, serum dose response imaging analysis indicated that hyphae formation in DFG5 and DCW1 mutants was defective. Conclusions These data indicate that DFG5 and DCW1 are required for hyphal morphogenesis and biofilm formation in C. albicans. These functions may be regulated via basal Hog1 MAPK which is required for transcriptional regulation of chitin synthesis.https://peerj.com/articles/5685.pdfCandida albicansDFG5DCW1Hog1Biofilms
spellingShingle Ryan Mancuso
Jennifer Chinnici
Charlene Tsou
Sujay Busarajan
Raveena Munnangi
Abhiram Maddi
Functions of Candida albicans cell wall glycosidases Dfg5p and Dcw1p in biofilm formation and HOG MAPK pathway
PeerJ
Candida albicans
DFG5
DCW1
Hog1
Biofilms
title Functions of Candida albicans cell wall glycosidases Dfg5p and Dcw1p in biofilm formation and HOG MAPK pathway
title_full Functions of Candida albicans cell wall glycosidases Dfg5p and Dcw1p in biofilm formation and HOG MAPK pathway
title_fullStr Functions of Candida albicans cell wall glycosidases Dfg5p and Dcw1p in biofilm formation and HOG MAPK pathway
title_full_unstemmed Functions of Candida albicans cell wall glycosidases Dfg5p and Dcw1p in biofilm formation and HOG MAPK pathway
title_short Functions of Candida albicans cell wall glycosidases Dfg5p and Dcw1p in biofilm formation and HOG MAPK pathway
title_sort functions of candida albicans cell wall glycosidases dfg5p and dcw1p in biofilm formation and hog mapk pathway
topic Candida albicans
DFG5
DCW1
Hog1
Biofilms
url https://peerj.com/articles/5685.pdf
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