924 Involvement of keratinocyte TLR2 receptor during fungal infection of the skin

The human skin is a complex organ which plays multiple roles, including protection of the body from external aggressions. However, mechanisms defense are sometimes insufficient, allowing microbial proliferation and tissue invasion. Fungi like filamentous pathogenic dermatophytes or commensal yeasts Malassezia genus cause superficial epidermal infections characterized by various degrees inflammation directly correlated with severity lesions. Since keratinocytes first cell type encountered fungi, this study aims to address role keratinocyte TLR2 receptor in fungal recognition initiation inflammatory response context dermatophytosis, infection. Indeed, activation its downstream signaling pathways leads induction proinflammatory factors, such as cytokines antimicrobial peptides (AMP). Using vitro models infection species furfur on reconstructed epidermis (RHE), overexpression release pro-inflammatory (e.g., IL-8, IL-6, IL-1β, TNFα) AMP hBD2, hBD3) were detected, respectively RT-qPCR total RNA, ELISA assays culture media. Overexpression was noticed infection, supporting potential involvement. To specifically investigate roles during responses, n/TERT deficient for generated deletion coding sequence using CRISPR/Cas9 method. Four different clonal populations holding deletions gene DNA sequencing. Western blot analysis confirmed no detectable protein TLR2-/- clones. TLR2+/+ keratinocytes, RHE obtained before M. furfur. course similar both RHE. Nevertheless, decreased TLR2-/-RHE, indicating involvement elements.