Mechanisms of Paracoccidioides infection in an in vitro model of lung epithelial barrier

• Grant number: 24/16060-7
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: January 01, 2025
• End date: February 28, 2027
• Field of knowledge: Biological Sciences - Microbiology
• Principal Investigator: Erika Suzuki de Toledo
• Grantee: Débora Tereza Lucas de Barros
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

Fungi of the genus Paracoccidioides are etiological agents of paracoccidioidomycosis, a systemic human mycosis that affects the lungs and other organs and is triggered by the inhalation of fungal propagules. Due to its route of infection, studies on the interaction between components of the pulmonary epithelial barrier (BEP) and Paracoccidioides are important to elucidate its pathogenicity mechanisms. Through cultivation in "Air Liquid Interface" (ALI), some cell lines, such as bronchial epithelial cells from Calu-3 human adenocarcinoma, differentiate, so that the cultures resemble a pseudostratified epithelium, making it possible to obtain a functional BEP "in vitro". One of the objectives of this project is to evaluate the effect of P. brasiliensis and P. lutzii yeasts, or their conditioned media, on the rupture of a BEP. Among the methods used to verify the integrity of the BEP are the measurement of transpithelial electrical resistance (TEER) and the analysis of the levels and cellular localization of proteins that form cell junctions (for example, "tight junctions"). In cases of BEP disruption, TEER and the levels and cellular location of these proteins may change. Furthermore, the participation of Paracoccidioides proteases and epithelial cell protein kinase D in BEP rupture will also be analyzed. The results of this project will allow us to define a new model of fungal infection in vitro using a type of cell culture that will more reliably mimic the conditions of an in vivo lung epithelium, enabling advances in studies on the mechanisms of pathogenicity of fungi and new antifungal therapies.