Human oral keratinocyte E-cadherin degradation by Candida albicans and Candida glabrata

Abstract

Background: E-cadherin (E-Cad) is a 120-kDa adhesive protein found in adherens junctions of the digestive tract epithelium. We tested the ability of two Candida strains to degrade human E-Cad in the Candida virulence factor perspective.

Materials and methods: We set out to study oral mucosal E-Cad degradation by clinical and reference strains of Candida albicans and Candida glabrata. We also included hyphal and secreted aspartic proteinase (Sap) mutants of C. albicans to test the effect of yeast/hyphal transition on the ability to degrade E-Cad. The tests were performed at pH 4 and pH 6 to determine the effect of local tissue acidity on the activation of Saps. The C. albicans strains used were: CCUG 32723; clinical strain SC5314 which is known to be strongly invasive; hyphal mutants of SC5314: HLC52 (efg1/efg1), HLC54 (cph1/cph1 efg1/efg1) and JKC19 (cph1/cph1); clinical strain B1134; Sap 1-3 and Sap 4-6 mutants of SC5314. The C. glabrata strains used were ATCC 90030, and the clinical strains 5WT and G212.

Results: The sonicated yeast cells of C. albicans JKC19 and SC5314, both in hyphal form, degraded E-Cad at pH 4. The 10x concentrated growth media of the strains HLC-52, HLC-54, 32723 and B1134; all in yeast form, caused degradation at pH 4, HLC-52 and HLC-54 also at pH 6. The C. glabrata strains did not degrade E-Cad.

Conclusions: pH is a strain dependent triggering factor in activating yeast or hyphal form related Candida Saps in degrading epithelial cell associated E-Cads.