A majority of mucosal and invasive fungal infections are caused by the oral fungal pathogen, Candida albicans. There is an alarming rise in antifungal drug resistance among Candida species. As a result, there is a need for novel antifungal drugs and therapeutics. The cell wall proteins in C. albicans play critical roles in cell wall biogenesis, host invasion and disease pathogenesis. However, currently there are no known antifungal drugs that target cell wall proteins. In C. albicans, DFG5 and DCW1 genes encode GPI-anchored glycosidases that are targeted to the cell wall. The simultaneous deletion of the DFG5 and DCW1 genes is lethal in C. albicans indicating that they are critical for survival. Our published findings in C. albicans indicate that the enzymes encoded by DFG5 and DCW1 are involved in cell wall protein cross-linking to the cell wall matrix. Data also show that DFG5 and DCW1 have a pivotal role in biofilm formation and regulate Hog1 MAPK (mitogen activated protein kinase) levels under basal conditions. Additionally, our recent preliminary data indicate that Dfg5 and Dcw1 may regulate chitin synthesis/remodeling, an important cell wall integrity determinant, via HOG MAPK pathway. However, the role of Dfg5 and Dcw1 cell wall proteins in virulence and pathogenesis of C. albicans is yet to be determined. Therefore, the objective of this proposal is to determine the functions of DFG5 and DCW1 in virulence and pathogenesis, in this important human fungal pathogen. Specifically, the project aims to determine the roles of DFG5 and DCW1 in 1) virulence via Hog1 MAPK signaling pathway and 2) in vivo pathogenesis in a mouse model of oral candidiasis. Targeting Dfg5 and Dcw1, and their functions will lead to novel and efficacious antifungal drugs.
An alarming rise in antifungal drug resistance among Candida species warrants the need for novel antifungal drug targets. Determining the roles of cell wall glycosidases, Dfg5 and Dcw1, in virulence and pathogenesis of C. albicans will lead to the development of novel and effective anti-Candida therapeutics targeting the cell wall.
