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Structural and functional characterization of the glycoprotein Ssp-4 of amastigotes forms from Trypanosoma cruzi

Grant number: 12/23150-5
Support Opportunities:Scholarships in Brazil - Doctorate (Direct)
Effective date (Start): July 01, 2013
Effective date (End): May 31, 2016
Field of knowledge:Biological Sciences - Parasitology - Protozoology of Parasites
Principal Investigator:Renato Arruda Mortara
Grantee:Pilar Sampaio Tavares Veras
Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil
Associated research grant:11/51475-3 - Molecular and cellular biology of the parasitism by Trypanosoma cruzi, AP.TEM


Trypanosoma cruzi, flagellate protozoan, is the etiologic agent of Chagas disease, of great importance in Latin America. Currently this protozoan is grouped into six distinct lineages, Tc I Tc VI based on molecular studies. In its life cycle, T. cruzi alternates between evolutionary stages that exhibit biochemical and morphological differences: epimastigotes, trypomastigotes and amastigotes; being the classic infective forms metacyclic trypomastigotes and bloodstream trypomastigotes. However, it is known that amastigotes derived from trypomastigotes, independent of intracellular stage in the mammal are also capable of infecting cells in vitro. These extracellular amastigotes (EA) have a stage specific surface antigen (Ssp-4), a 70-84 kDa glycoprotein anchored to the membrane by GPI and recognized by monoclonal antibodies (mAbs) 2C2 and 1D9. It is also known that the Ssp-4 is gradually released into the extracellular environment. However, structural and functional aspects of this surface glycoprotein has not been described in the literature. To date, preliminary data from this project have revealed that carbohydrate epitopes defined by mAbs 2C2 and 1D9 are differentially expressed among different isolates, and this distribution seems to be related with the infectivity of these parasites. Thus, the present study aims to characterize structurally and functionally Ssp-4 and confirm the relationship of its expression with the profile of infectivity in different T. cruzi isolates. We intend to elucidate the amino acid sequence of Ssp-4 by mass spectrometry. Then evaluate the infectivity of strains G and CL overexpressing Ssp-4. We will verify the relationship between the expression and distribution of carbohydrate epitopes of Ssp-4 and infectivity of the parasite. Finally identify the release of Ssp-4 to the extracellular medium by investigating the vesicles secreted by amastigotes. (AU)

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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)
FLORENTINO, P. T. V.; REAL, F.; BONFIM-MELO, A.; ORIKAZA, C. M.; FERREIRA, E. R.; PESSOA, C. C.; LIMA, B. R.; SASSO, G. R. S.; MORTARA, R. A.. An Historical Perspective on How Advances in Microscopic Imaging Contributed to Understanding the Leishmania Spp. and Trypanosoma cruzi Host-Parasite Relationship. BIOMED RESEARCH INTERNATIONAL, . (14/21338-2, 10/19335-4, 13/05385-8, 12/23150-5)
FLORENTINO, PILAR T. V.; REAL, FERNANDO; ORIKAZA, CRISTINA M.; DA CUNHA, JULIA P. C.; VITORINO, FRANCISCA N. L.; CORDERO, ESTEBAN M.; SOBREIRA, TIAGO J. P.; MORTARA, RENATO A.. A Carbohydrate Moiety of Secreted Stage-Specific Glycoprotein 4 Participates in Host Cell Invasion by Trypanosoma cruzi Extracellular Amastigotes. FRONTIERS IN MICROBIOLOGY, v. 9, . (12/23150-5, 11/51475-3)

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