Banca de DEFESA: JESSICA AMARAL LOPES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JESSICA AMARAL LOPES
DATE: 16/05/2022
TIME: 07:30
LOCAL: Sala Virtual Remota
TITLE:

PAPEL DA BthTX-I E BthTX-II ISOLADAS DO VENENO DE Bothrops jararacussu NA POLARIZAÇÃO E FUNÇÃO DE PBMCs

KEY WORDS:

PLA2. BthTX-I. BthTX-II. Macrophages. Polarization.

PAGES: 102
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Bothrops venom has a large amount of phospholipase A2 enzymes (PLA2s) that are responsible for myotoxicity, inflammatory reaction, and leukocyte activation in envenomation. PLA2s are proteins that have enzymatic activity and can hydrolyze phospholipids at the sn-2 position, releasing fatty acids and lysophospholipids, precursors of eicosanoids important mediators of inflammatory conditions. It has already been demonstrated in the literature that leukocytes (neutrophils and macrophages) contribute to the development of the inflammatory response induced by bothropic venoms and the PLA2s isolated from these venoms contribute to this process. However, the role that these enzymes play in the activation and function of human peripheral blood mononuclear cells (PBMCs) is not known. Bearing this in mind and knowing that the local inflammatory condition is persistent in envenoming caused by snakes of the Bothrops genus, the present study aimed to show how the two secreted isolated PLA2s from the venom of Bothrops jararacussu (BthTX-I and BthTXII) affect the functioning and polarization of PBMCs during the period of cell differentiation. For this, PBMCs were isolated and stimulated with RPMI (negative control), LPS+IFN-γ (positive control for M1, classical macropahges), IL-4+IL-13 (positive control for M2, alternative macrophages), BthTX-I or BthTX-II for 7 days. The following parameters were analyzed: cell morphology, phenotype, gene expression by RT-qPCR of pro-inflammatory (TNF-α, IL-6, IL-12 and iNOS) and anti-inflammatory (TGF-β, IL-10 and Arg-1) mediators corresponding to each phenotype and functional cell assays such as formation of lipid bodies (CLs) and phagocytosis. The morphological assays showed that the PBMCs on the 1st day of differentiation showed less complexity when compared to the 7th day. The immunophenotyping of PBMCs stimulated with BthTX-I and BthTX-II showed an increase in polarization for the antiinflammatory profile on the 1st day and this pattern was maintained on the 3rd, 5th and 7t day, demonstrating that immunophenotyping alone is not a parameter to analyze the polarization. The gene expression of pro-inflammatory and anti-inflammatory mediators was detected throughout the differentiation period studied demonstrating high plasticity of these cells and the importance of toxins (BthTX-I BthTX-II) in modulating these profiles. Functional assays of CL formation demonstrated that PBMCs stimulated with the toxins exhibited an increase in the number of CLs both within 1 hour and at the end of the 7th day. Another functional parameter, phagocytosis of zymosan particles was increased by the two toxins within 1 hour. Thus, the present study indicates for the first time that even evaluating during the entire period of cell differentiation and, taking into account the morphological, genetic and protein expression, phenotype and functional assays, both secreted PLA2s promote both polarization profiles in the PBMCs, exhibiting great cellular plasticity, which may be crucial to try to minimize the local damage caused by these bothropstoxins.

BANKING MEMBERS:
Externa à Instituição - ADRIANA LIMA VALLOCHI - FIOCRUZ
Externo à Instituição - FABIO HENRIQUE KWASNIEWSKI - UEL
Externo à Instituição - GUSTAVO BATISTA DE MENEZES - UFMG
Presidente - 1726461 - JULIANA PAVAN ZULIANI TRENCH DE SOUZA
Externa à Instituição - LUCIANE ALARCÃO DIAS MELICIO - UNESP