Th1 cell differentiation in patients with Chagas' heart disease and indeterminate form of Chagas' Disease: phenotypic, gene expression and epigenetic analysis

• Grant number: 22/08158-1
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: January 01, 2023
• End date: January 31, 2024
• Field of knowledge: Biological Sciences - Immunology - Applied Immunology
• Principal Investigator: Edecio Cunha Neto
• Grantee: Greyce Luri Sasahara
• Host Institution: Instituto do Coração Professor Euryclides de Jesus Zerbini (INCOR). Hospital das Clínicas da Faculdade de Medicina da USP (HCFMUSP). Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

It is estimated that 6 to 7 million people are infected with Trypanosoma cruzi worldwide. Chagas Disease, caused by this parasite, is endemic in Latin America, where it is a major cause of hospitalization for heart failure. About 30% of those infected progress in the chronic phase of the infection to chronic Chagas' heart disease (CCC), characterized by persistent destructive myocarditis, while the rest of patients mostly remain in the asymptomatic "indeterminate" form (IF) for life. The inflammation observed in CCC is characterized by the presence of T helper 1 (Th1) lymphocytes infiltrated in the heart, as well as the presence of IFN-³ in cardiac tissue. The frequency of these cells and the amount of IFN-³ in the plasma of CCC patients are also increased when compared to individuals with the asymptomatic IF. On the other hand, a lower frequency of Th17 lymphocytes is observed in CCC individuals when compared to the IF. Previous data suggest that naive CD4+ T lymphocytes are heterogeneous in terms of gene expression and that differences in nuclear chromatin accessibility may contribute to preferential differentiation for some cell subtypes. Furthermore, the plasticity of CD4+ T lymphocytes allows for transdifferentiation between subtypes, such as the conversion of Th17 lymphocytes to Th1. Therefore, we hypothesized that a preferential differentiation of Th1 lymphocytes in patients with CCC, either due to differences in chromatin accessibility and gene expression of naive CD4+ T lymphocytes or by the transdifferentiation of Th17 lymphocytes into Th1. Therefore, in this work, we intend to comparatively evaluate, by flow cytometry, the differentiation of naive CD4+ T lymphocytes isolated from the PBMC of CCC and IF patients into Th1 cells. We will also evaluate in the PBMC of CCC and FI patients if there is evidence of transdifferentiation of Th17 lymphocytes into Th1, using specific markers in flow cytometry. Finally, we will evaluate the chromatin accessibility and gene expression of PBMC in CCC and FI patients, using concomitant single-cell ATAC-seq and single-cell RNAseq in the same cells. We believe that this combination of experimental strategies will allow a better understanding of the mechanisms that favor the differentiation of Th1 lymphocytes and their possible relationship with the differential progression of Chagas disease, helping to develop future therapeutic and diagnostic approaches. (AU)