The V-ATPase V ₀ c' subunit is critical for Candida albicans pathogenicity in oral epithelial infection

The vacuolar-type H⁺-ATPases (V-ATPase) are a multi-subunit enzyme located in the Candida albicans (C. albicans) vacuolar membrane. It is responsible for ion transportation and modulates several cellular responses, with the key structure being the c ring in the V₀ domain. However, c ring's role in oral epithelial infection remains unclear.

This study aimed to reveal the role of V₀c' subunit (encoding the gene VMA11), one of the subunits assemble c ring for oral Candidiasis in vitro and in vivo.

VMA11 deletion and complementation mutants were constructed to evaluate the oral epithelial infection abilities of V₀c' subunit, and western blotting and RT-qPCR were used to assess the regulate pathways for hyphal formation. Human oral mucosal keratinocyte (HOK) cells infected by C. albicans were subjected to transcriptome sequencing, and further validated using western blotting and immunofluorescence. Then, the impact of c ring specific inhibitor Bafilomycin A1 on oral epithelial infection by C. albicans were examined.

A VMA11-deleted mutant displayed reduced ATP contents, which decreased lower Ras and cyclic adenosine monophosphate (cAMP) levels, leading to inhibited hyphal growth by affecting the cAMP-protein kinase A (PKA) pathway. Additionally, the absence of VMA11 further weakened C. albicans adhesion and damage capabilities toward oral epithelial cells, resulting in a diminished epithelial response associated with mitogen-activated protein kinase (MAPK) signaling. Bafilomycin A1 was then proved to effectively protect oral epithelium from C. albicans infection, which was consistent with the phenotypes of VMA11 deletion mutant.

Our findings highlight the crucial functions of V-ATPase V₀c' subunit in oral epithelial infection and suggest that targeting the V-ATPase c ring may be a promising antifungal strategy against oral candidiasis.