Comprehensive analysis of human keratinocyte interactions with Candida albicans and Candida parapsilosis

The skin provides extensive protection against several pathogens. On its surface epithelial cells, or keratinocytes, respond to microbial stimuli primarily through the secretion of antimicrobial peptides and inflammatory cytokines. However, their alarming function is restricted to invading pathogenic organisms. Recent microbiome studies suggest that Candida species are natural colonisers of the human skin. However, discrepancies are present regarding the presence of C. albicans on the healthy skin, that is also frequently associated with cutaneous candidiasis. Therefore, here we aimed to investigate human keratinocyte responses to C. albicans and to another Candida species, C. parapsilosis - that is more likely to resemble skin commensals - in order to assess and compare the nature of skin epithelial cell responses to Candida species. Our results indicate that humoral, cellular and metabolic activities are more pronounced in the presence of C. albicans, than C. parapsilosis, suggesting a naturally occurring alarming response against this species.