Malassezia furfur invasiveness in a keratinocyte cell line (HaCat): effects on cytoskeleton and on adhesion molecule and cytokine expression

The lipophilic yeast Malassezia furfur is. a member of the cutaneous microb iota, also associated with several chronic diseases, such as pityriasis ver sicolor, folliculitis, seborrhoeic dermatitis, and some forms of atopic der matitis, psoriasis and confluent and reticulate papillomatosis. In this stu dy we determined the immunomodulatory and invasive capacity of M. furfur in a human keratinocyte cell culture, HaCat. At a yeast cell to HaCat ratio o f 30:1, M. furfur penetration was only 30% with poor phagolysosome fusion a nd with cytoskeleton modification. Transglutaminase I gene expression was a lso inhibited, supporting the hypothesis that M. furfur causes an initial b reak in the barrier function of the epidermis. Moreover, we demonstrated th at M. furfur modulates proinflammatory and immunomodulatory cytokine synthe sis by downregulating IL-1 alpha and by inhibiting IL-6 and TNF-alpha and b y upregulating IL-10 and TGF-beta1. The suppressed inflammatory response in duced by M. furfur may play a role in chronic disease.