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Characterization of Toxoplasma gondii microneme proteins interaction with TLR2 glycans

Grant number: 12/20809-6
Support Opportunities:Scholarships in Brazil - Master
Effective date (Start): February 01, 2013
Effective date (End): July 31, 2014
Field of knowledge:Biological Sciences - Biochemistry - Molecular Biology
Principal Investigator:Maria Cristina Roque Antunes Barreira
Grantee:Flávia Costa Mendonça Natividade
Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil


Toxoplasmosis is caused by the protozoan Toxoplasma gondii, an intracellular parasite able of infecting any nucleated cell of warm-blooded animals. In the apical region of this parasite are several organelles that release a range of molecules involved in adhesion and invasion of the host cell. Some proteins released by organelles called micronemes (MICs) have adhesive domains essential for virulence of the parasite; they can associate with each other on the surface of tachyzoite, forming complexes, such as TgMIC1/MIC4/MIC6.Previously, we have demonstrated that the subcomplex TgMIC1/MIC4 binds to lactose and stimulates macrophages to secrete IL-12. More recently, experiments that have used HEK293A cells transfected with TLR2, revealed that there is recognition of N-glycans of TLR2 ectodomain by carbohydrate recognition domain of MICs, suggesting that this interaction arises in the production of IL-12 induced by TgMIC1 and TgMIC4.This idea was greatly enhanced by the observation that macrophages from TLR2-/- mice fail to respond to MICs stimulation through IL-12 production. Thus, we have strong indications that TgMIC1 and TgMIC4 interact through the lectin site with Toll-like receptors and, thus, promote the release of pro-inflammatory cytokines and modulate the immunity against the parasite.This project aims to detail the study of the microneme proteins interaction with TLR2 glycans using mutant forms of receptor for N-glycosylation sites. Therefore, we can identify glycan(s) key(s) to microneme proteins induce cell activation. In a second step, the glycan(s) key(s) will have the structure determinate for comparison with glycidic structures, target of recognition by MICs, as revealed by glycoarray

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
PAIVA ALEGRE-MALLER, ANA CLAUDIA; MENDONCA, FLAVIA COSTA; DA SILVA, THIAGO APARECIDO; OLIVEIRA, ALINE FERREIRA; FREITAS, MATEUS SILVEIRA; HANNA, EBERT SEIXAS; ALMEIDA, IGOR C.; GAY, NICHOLAS J.; ROQUE-BARREIRA, MARIA CRISTINA. Therapeutic Administration of Recombinant Paracoccin Confers Protection against Paracoccidioides brasiliensis Infection: Involvement of TLRs. PLoS Neglected Tropical Diseases, v. 8, n. 12, . (13/14161-6, 12/20809-6, 14/05359-0, 12/09611-0, 10/01112-9)

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