UNRAVELING METABOLIC AND MITOCHONDRIAL PATHWAYS IN T. CRUZI-SPECIFIC CD8 EFFECTOR T CELLS: EXPLORING POTENTIAL INTERVENTIONS

MARIA FLORENCIA HELLRIEGEL; RUTH ELIANA BAIGORRI; MATIAS EZEQUIEL VAZQUEZ VIGNALE; CAMILA FONTANARI

Congreso; LXXI Reunión Anual de la sociedad argentina de inmunología; 2023

Trypanosoma cruzi causes Chagas´ disease, endemic in Latin America and globally present. The infection involves an acute phase (AP) with high parasitemia that transitions to chronic stage, potentially leading to Chagasic pathology. CD8 T cells are crucial for host resistance, but T. cruzi-specific CD8+ T cell (Tc-CD8) immunity develops slowly, with reduced breadth and may acquire dysfunctional features. Mitochondria plays a key role in CD8 T cell immune response. Mitochondrial membrane potential (MMP) and mitochondrial superoxide (mROS) levels impact in effector function. Our previous results showed an increase in total CD8 T cells with depolarized mitochondria (DM) and mROS during AP of BALB/c infection. Then, the aim of this study was to improve mitochondrial quality on CD8 T cells and explore its impact on infection. To achieve this, Nicotinamide Riboside (NR), a precursor to NAD+ and mitophagy inducer was used. BALB/c mice were infected (I) with 500 trypomastigotes from Tulahuen strain (tp-Tul). Non infected (NI) animals were used as controls. Mice were treated with NR (500 mg/kg/day by oral gavage) or PBS from 5-20 days post infection (dpi) (I-NR or I-PBS). Spleen cells were isolated at 21 dpi. We examined mitochondrial mass (MM), MMP and mROS production by FACS combining MMP-dependent, MMP-independent mitochondrial dyes and MitoSOX respectively. We observed that I-NR mice with lower parasitemia levels exhibit better biochemical parameters in plasma. They also displayed a tendency to decrease in the frequency of effector (E) CD8+ T cells with DM and mROS production. Likewise, I-NR mice exhibited a higher frequency of IL-2-producing E CD8+ T cells. Moreover, we aimed to extend our investigation of mitochondrial metabolism to Tc-CD8 T cells. Then, C57BL/6 mice were inoculated with 5000 tp-Tul. Spleen cells were obtained at 9, 20 and 78 dpi. Tc-CD8 T cell response was measured by FACS using tetramers loaded with the parasite immunodominant peptide Tskb20 in E cells. Moreover, glucose uptake through 2-NBDG probe and expression of the glutamine transporter CD98 was assessed by FACS. We observed that the peak of parasitemia correlates with a higher number of total and E Tc-CD8 cells. These cells showed an increase in MMP at 9 dpi (p=0,05) while mROS production and MM were higher at 20 dpi (p