Differential phospholipase gene expression by Candida albicans in artificial media and cultured human oral epithelium

Phospholipases B1, B2, C and D of Candida albicans play a significant role in the host invasive process. Hence we evaluated the in vitro expression of PLB1, PLB2, PLC1 and PLD1 in phospholipase-positive (PL(+)) and -deficient (PL(-)) C. albicans isolates in egg yolk agar (EYA), yeast peptone dextrose broth (YPD), and in a model of oral candidiasis based on reconstituted human oral epithelium (RHOE). The growth of Candida was then determined in YPD and its cellular invasion was investigated using the RHOE model. The PL(+) group demonstrated PLB1, PLB2, PLC1 and PLD1 expression in both EYA and YPD, in contrast to the PL(-) group, which expressed only PLB2 and PLD1. Although PL(+) isolates grew profusely in the RHOE model, they expressed only PLB2, PLC1 and PLD1, and not PLB1. Gene expression investigations could not be carried out with PL(-) isolates due to their inability to grow in the RHOE model. Significant growth differences in YPD medium were also observed within the PL(+) and PL(-) groups. Taken together, these findings indicate that phospholipase gene expression in C. albicans is differentially affected by their growth milieu, and this in turn may modulate the disease outcomes in vivo.