Banca de QUALIFICAÇÃO: JOHNY WYSLLAS DE FREITAS OLIVEIRA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : JOHNY WYSLLAS DE FREITAS OLIVEIRA
DATA : 31/07/2019
HORA: 14:00
LOCAL: Sala Carl Peter von Dietrich - Departamento de Bioquímica
TÍTULO:

Characterization of antiparasitic activity of Sodium dietyldithiocarbamate trihydrate against different strains of Trypanosoma cruzi

PALAVRAS-CHAVES:

DETC, Trypanosoma cruzi, Antiparasitic activity, in silico assays, proteic targets, proteolytic action.

PÁGINAS: 107
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

Chagas Disease is a zoonosis caused by the single-celled protozoan Trypanosoma cruzi that affects thousands of people around the world. For the therapeutic control of Chagas Disease, conventional drugs besides being highly cytotoxic do not present satisfactory responses to the chronic phase of the disease. T. cruzi has a biological cycle of the heteroxenic type between the invertebrate Triatomineo vector and a mammalian host. During the infection, the parasite presents a mechanism of response to the oxidative damage triggered by the host system, one of which confers the resistance capacity to the reactive species of oxygen and nitrogen. Dithiocarbamates in turn are a group of highly versatile chemical compounds, due to their chemical structure formed by an amine and a carbon disulfide, assessing the ability of interaction with metals and oxidative burst. DETC in previous studies demonstrated antiparasitic activity against Leishmania sp. Therefore, this work aimed to evaluate the antiparasitic activity of the DETC against different strains of T. cruzi in different evolutionary forms. Additionally, it was sought to characterize its antiparasitic mechanism of action and to elucidate possible molecular targets. For this purpose, antiparasitic assays were performed in 24h and 48h periods, evaluating different concentrations of DETC ranging from 0.044 μM to 4.44 μM for the epimastigote and trypomastigote forms, through the resazurin assays and clear camera count, in which high activity was observed and the dose required to eliminate 50% of the parasites (Ic50) was determined to be around 0.444 μM. In addition, DETC-elicited the mechanisms of cell death by DETC at concentrations of (4.44 μM, 0.444 μM, 0.044 μM) against the T. cruzi epimastigote form in the 24 hours period were analyzed using the kit Annexin V-FITC, in which very low activity was observed for the Qmm9 and Cl Brener strains and no response for the Dm28c and Y strains. Also, the mitochondrial damage caused by DETC at concentrations of (0.444 μM, 1.11 μM, 2, 22 μM) under T. cruzi in the 24 h period through the rhodamine-123 assay where a strong action of DETC was observed on the different strains inhibiting the mitochondrial membrane potential. In addition, the structural alterations were analyzed by scanning electron microscopy showing membrane changes, rupture and formation of pores formed when the Ic50 doses were applied. In addition, we attempted to analyze the action of DETC in concentrations ranging from 0.625 mM to 10 mM on proteolytic proteins through zymography, being analyzed in gel under the extracts of the parasites and a reduction in the potential of the proteolytic activity of the extracts of the parasites was verified reached 40%. Finally, the identification of possible molecular targets through in silico molecular docking assays using the Vina Auto-dock software, it was found that the DETC can present a high capacity to interact to inhibit α-Carbonic anydrase, analyzing the positioning of anchor . Therefore, DETC is an excellent candidate for alternative treatment of Chagas' disease due to high antiparasitic activity, does not present a high cytotoxicity and triggers actions on specific compartments of the parasite. In addition, α-Carbonic anhydrase has been identified as a possible target for or DETC.

MEMBROS DA BANCA:
Presidente - 2213126 - VALTER FERREIRA DE ANDRADE NETO
Externo ao Programa - 1715109 - DANIEL DE LIMA PONTES
Externo ao Programa - 1893445 - EUZEBIO GUIMARAES BARBOSA