XI International Meeting on Paracoccidioidomycosis

XI International Meeting on Paracoccidioidomycosis

Resume:37-1

Poster (Painel)

37-1

Photodynamic inactivation of Paracoccidioides brasiliensis using a cationic porphyrin and gene expression response to photodynamic treatment਀

Authors:

Luciane Madureira de Almeida (UEG - Universidade Estadual de GoiásUFG - Universidade Federal de Goiás) ; Fabiana Fonseca Zanoelo (UFG - Universidade Federal de GoiásUFMS - Laboratório de Bioquímica) ; Kelly Castro (UFG - Universidade Federal de Goiás) ; Iouri E Borissevitch (USP - Universidade de São Paulo) ; Célia Maria de Almeida Soares (UFG - Universidade Federal de Goiás) ; Pablo José Gonçalves (UFG - Universidade Federal de Goiás)

Abstract

Paracoccidioides brasiliensis is a human pathogenic fungus that causes paracoccidioidomycosis (PCM), one of the most common causes of death due to chronic infections and parasitic diseases in Brazil. Frequently, several years of treatment are required and in the some case are not effective. Thus, the search for alternative therapies is increasingly relevant and necessary. Among the new therapies, Photodynamic Inactivation (PDI) is a promising option to kill pathogenic microorganisms. This technology combines nontoxic dye with harmless visible light that together generate reactive oxygen species toxic to cells. The purpose of this study was to evaluate the effects of PDI on the viability of P. brasiliensis, using TMPyP cationic porphyrin as a photosensitizer at different concentrations and different light exposition times. Two different experiments, tenfold serial dilutions and counting the Colony-Forming Unit number, showed a phototoxic effect of porphyrin in P. brasiliensis, in vitro. Although the biological effects of PDI treatment are known, the molecular mechanisms which give rise cell damage are poorly defined. To understand the oxidative answer to stress and the production of antioxidant enzymes involved in the P. brasiliensis response to PDI, we analyzed the gene expression of two genes associated with the HOG MAPK pathway (hog1 and ssk1); three genes coding to antioxidant enzymes (superoxide dismutase - SOD; glutathione peroxidase - GPx; cytochrome c peroxidase - CCP) using qRT-PCR. All the analyzed transcripts were over-expressed after PDI treatment. These studies suggest that TMPyP is an effective sensitizer for photodynamic inactivation and that oxidative stress generated in our experimental conditions greatly induces antioxidant activity in P. brasiliensis cells. ਀ Supported by: CNPq, FINEP, FAPEG਀

Keyword: photodynamic therapy, pathogenic fungus, reactive oxygen species, oxidative stress, gene expression

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