DURING ACUTE PHASE OF Trypanosoma cruzi INFECTION, DISTURBED MITOPHAGY CONTRIBUTES TO DAMAGED MITOCHONDRIA ACCUMULATION IN EFFECTOR CD4 T CELLS LEADING TO APOPTOSIS

ANA, YAMILE; BAIGORRI RUTH; CERBÁN FABIO; STEMPIN, CINTHIA CAROLINA

Congreso; Reunión de Biociencias 2021; 2021

Chagas disease is characterized by inefficient host immune responseduring acute phase of infection, enabling the establishmentof chronic disease. We have recently demonstrated that acute infectiontriggers mitochondrial ROS (mROS) production and mitochondrialalterations in effector CD4 T cells leading to functional alterationsand apoptosis. The aim of our work was to evaluate the mechanisminvolved in the accumulation of damaged mitochondria, and if thiscould be prevented by the antioxidant N-acetyl cysteine (NAC) orthe mitophagy inducer Nicotinamide Riboside (NR). To achieve this,CD4 T cells were isolated from spleen of non-infected (NI), acute(AP) and chronic phase (CP) infected BALB/c mice, with 500 trypomastigotes.Mitophagy was evaluated using mitochondrial potentialindependent probe (MTgreen) and antibodies for LC3 and LAMP1.Cells were cultured with or without chloroquine and colocalizationwas evaluated by confocal microscopy. CD4 T cells from AP culturedwith chloroquine did not show significant increase in MTgreen andLAMP1 colocalization compared to CCCP-treated NI CD4 T cellsused as positive control (*p<0,05) suggesting a defect in mitophagy.Then, we aimed to evaluate by flow cytometry, mROS production,frequency of cells with damaged mitochondria and apoptosis in effectorCD4 T cells from AP infected mice treated with NAC, NR andvehicle as control. We did not found differences between NAC andcontrol group. In contrast, NR treatment reduced the percentage ofCD4 T cells with damaged mitochondria (*p<0.05), although we didnot observed difference in mROS production. Moreover, apoptosisfrequency was also diminished (**p<0.01). Depolarized mitochondriaaccumulation, probably due to a defect in mitophagy, could berestored by NR, and thus prevent apoptosis. Taken together, thisevidence stablishes association between accumulated damagedmitochondria, and impaired mitophagy leading to apoptosis in CD4T cells during acute T. cruzi infection.