New therapies and biomarkers in paracoccidioidomycosis: study of antifungal activity and toxicity of alkyl galates in alternative models and mice and identification of circulating microRNAs

Author(s)

Junya de Lacorte Singulani

• Document type: Doctoral Thesis
• Press: Araraquara. 2017-03-14.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Farmacêuticas. Araraquara
• Defense date: 2017-02-10
• Advisor: Maria José Soares Mendes Giannini; Francisco Javier Enguita

Abstract

Paracoccidioidomycosis (PCM) is a systemic mycosis caused by the fungi of the genus Paracoccidioides, which is endemic in Latin America. Three aspects are of great importance in this disease: the development of new antifungals and the use of alternative models for their study and also, the search of biomarkers for diagnosis. The number of antifungal agents available is restricted, and problems such as adverse effects, drug interactions and the development of resistance are related to them. In this context, the search for new compounds has increased. In addition, alternative animal models such as Caenorhabditis elegans, zebrafish (Danio rerio) and Galleria mellonella have been used for the study of new drugs in a simple and large scale manner. In this work, these models were used to evaluate the antifungal efficacy and toxicity of gallic acid and its alkyl esters derivatives (gallates). The compound with the best activity in these models was tested in mice. Dodecyl gallate presented better efficacy and lower toxicity in the C. elegans - C. albicans model and lower toxic effect in zebrafish embryos. However, in G. mellonella and in mice infected with Paracoccidioides sp., the compound showed no antifungal efficacy, which may be explained due to its low bioavailability. To resolve such a problem, gallates were associated with a nanostructured lipid system. Such association was beneficial, resulting in lower toxicity in lung fibroblasts and zebrafish, as well as in greater efficacy in the murine model. Another aspect of this study concerns the investigation of microRNAs for PCM. MicroRNAs are small non-coding RNAs that perform functions in biological processes and diseases. Thus, with the aid of RT-qPCR, eight microRNAs were differentially expressed in the serum of patients with chronic PCM. In the lung cells, distinct microRNAs were observed according to a phylogenetic species of Paracoccidioides sp. that infected them. The microRNAs found in appear to be related to the processes of adhesion, apoptosis and immune response to the infection and can serve as biomarkers and therapeutic tools of the disease. (AU)

• FAPESP's process: 14/10446-9 - Evaluation of new therapies and biomarkers in paracoccidioidomycosis: antifungal activity of alkyl gallates in alternative models and mice and identification of circulating microRNAs
• Grantee: Junya de Lacorte Singulani
• Support Opportunities: Scholarships in Brazil - Doctorate