Purinergic signaling modulates CD4+ T cells with cytotoxic potential during Trypanosoma cruzi infection.

Chagas disease, caused by Trypanosoma cruzi, is endemic to Latin America and is characterized by chronic inflammation of cardiac tissues due to parasite persistence. Hypoxia within infected tissues may trigger the stabilization of HIF-1 and be linked to ATP release. Extracellular ATP exhibits microbicidal effects but is scavenged by CD39 and CD73 ectonucleotidases, which ultimately generate adenosine (ADO), a potent immunosuppressor. Here, we comprehensively study the importance of HIF-1 stabilization and the CD39/CD73/ADO axis, on CD4+ T cells with the cytotoxic phenotype, in facilitating the persistence of T. cruzi. Myocardial infection induces prominent areas of hypoxia, which is concomitant with HIF-1α stabilization in T cells and linked to early expansion of CD39+CD73+CD4+ T cell infiltrating population. Functional assays further demonstrate that HIF-1 stabilization and CD73 activity are associated with impaired CD4+ T cell cytotoxic potential. RNA-Seq analysis reveals that HIF-1 and purinergic signaling pathways are overrepresented in cardiac tissues of patients with end-stage Chagas disease. The findings highlight a major effect of purinergic signaling on CD4+ T cells with potential cytotoxic capacity in the setting of T. cruzi infection and have translational implications for therapy.