Screening of new antifungal molecules and characterization of pathogenicity process of the dermatophyte Trichophyton rubrum

Abstract

Trichophyton rubrum is the main causative agent of superficial mycoses in the skin and nails in Brazil and in the world. This dermatophyte uses keratinized substrates as the primary nutrient during infection. Nowadays, there is an increase in dermatophytoses in immunocompromised patients, in which these lesions present a more penetrating and invasive character, making treatment difficult. Chalcones and curcumin have pronounced antifungal and anti-inflammatory activity. Modifying the chemical structure of these molecules of natural origin may open up a new perspective of more effective antifungal therapy. The pathogenicity process of T.rubrum is initiated by the process of adherence of the fungus and the penetration of keratinized tissue, followed by the activation of inflammation and production of reactive oxygen species by macrophages, which are essential for the host defense mechanism of infection. However, there are currently few cellular and molecular strategies available that allow better understanding of the fungus-host relationship due to the limitations of the models that mimic this interaction. The culture medium added with protein substrates and the co-culture of T.rubrum in human keratinocyte lineage can be used to simulate surface infection and coculture in macrophages cells can mimic the systemic infection. Our research group demonstrated that the analysis of Dual RNA seq of the human keratinocyte cell line and T. rubrum co-culture revealed the modulation of genes involved in the fungal infection mechanism, cytokine production, defense and maintenance of keratinocyte cellular homeostasis. In addition, the microRNA-seq of human macrophages co-cultured with T.rubrum was performed. In silico analysis of the target genes of the modulated microRNAs was related to inflammatory response, oxidative stress, apoptosis, drug resistance and cell proliferation. The objective of this project is to evaluate new antifungal molecules (chalconoides and curcuminoids) and to characterize the pathogenic process of T. rubrum using different infection models. To achieve this aim, we intend to identify the modulated proteins in culture medium with keratin, to evaluate the expression of fungal genes and selected human keratinocytes in Dual RNA seq in different co-culture situations; in order to characterize the effect of pathways modulated by micro RNAs of macrophages such as oxidative stress, inflammatory process (release of interleukins), apoptosis and phagocytosis during infection. Through the obtained results, it is expected to show new molecular targets related to the pathogenic process of the dermatophyte, as well as to identify new antifungal molecules. (AU)