CARD9 signaling is not involved in the antifungal innate response to experimental dermatophytosis.

MARIEL ALMEIDA; IGNACIO BECCACECE1, VERÓNICA BURSTEIN1, LORENA GUASCONI1, CRISTIAN MENA1, LAURA CERVI1, ; MICHAIL LIONAKIS; CHIAPELLO LAURA S.

San Luis

Congreso; eunión Anual de la Sociedad Argentina de Inmunología (SAI); 2023

Sociedad Argenina de Inmunología

CARD9 signaling is not involved in the antifungal innate response to experimental dermatophytosisMariel Almeida1, Ignacio Beccacece1, Verónica Burstein1,Lorena Guasconi1, Cristian Mena1, Laura Cervi1, Michail Lionakis2, Laura Chiapello1.1Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET). Departamento de Bioquímica Clínica. Facultad de Ciencias Químicas. Universidad Nacional de Córdoba. Córdoba, Argentina.2Fungal Pathogenesis Section, Laboratory of Clinical Immunology and Microbiology. National Institute of Allergy and Infectious Diseases (NIAID, NIH). U.S.ACARD9, a caspase recruitment domain-containing signaling protein, plays an essential role in downstream signaling and gene activation induced by C-type lectin receptors in response to fungal glycans, contributing significantly to the antifungal immunity. Patients with autosomal recessive CARD9 deficiencysuffer uncommon forms of invasive fungal diseases, such as Candida albicans encephalitis, extrapulmonary aspergillosis, phaeohyphomycosis, and deep dermatophytosis. Nevertheless, the precise CARD9-mediated mechanisms involved in cutaneous antifungal defenses remain poorly explored. In our laboratory, we have previously developed an experimental model of dermatophytosis in C57BL/6 that recapitulate human infection, characterized by fungal invasion and neutrophil recruitment in the epidermis and an IL-17A-mediated immune response.In this study, we aimed to investigate the in vivo relevance of CARD9 expression during Nannizzia gypsea experimental dermatophytosis.C57BL/6 (WT) and CARD9-/- (CARD9 KO) mice were epicutaneously infected in the back with a Nannizzia gypsea suspension (OD 1.0 at 450 nm) or treated with PBS (uninfected controls). At 3-, 6/7- and 20-days post-infection (dpi), back skin sections were incubated with Trypsin/EDTA (2 h,37°C) and epidermal cell suspensions were obtained to analyze Card9 gene expression (RT-PCR), IL-17A- producing cell populations (FACS), chemokine and cytokine production (ELISA) and fungal burden (CFU/gr skin). The RT-PCR analysis of sorted epidermal cells from N. gypsea- infected WT mice (3 and 6 dpi) revealed an exclusive detection of Card9 RNA expression within myeloid cell populations (CD45+CD11b+ epidermal cells). Interestingly, CARD9KO mice exhibited a lower fungal burden after 3 dpi compared to WT mice, (1657 ± 1167 vs. 4306 ± 2968 CFU/gr skin, respectively, p