Th1 cell differentiation in patients with Chagas cardiomyopathy and the indeterminate form of Chagas disease: a phenotypic, gene expression, and epigenetic analysis using single-nucleus ATAC-seq and RNA-seq.

• Grant number: 24/19182-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: May 01, 2025
• End date: April 30, 2028
• Field of knowledge: Biological Sciences - Immunology - Applied Immunology
• Principal Investigator: Edecio Cunha Neto
• Grantee: Isabela Pazotti Daher
• 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
• Associated research grant: 22/00758-0 - Mitochondria, interferon-gamma and genetics in Chagas Disease cardiomyopathy: pathogenesis, therapeutic targets and prognostic markers, AP.TEM

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-¿ in cardiac tissue. The frequency of IFN-¿-secreting T cells and the amount of IFN-¿ 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. Moreover, a higher frequency of monocyte populations associated with an inflammatory environment are found in CCC as compared with 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 allow 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 (both lymphoid and myeloid components) 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.