Mitochondrial and metabolic alterations may influence CD4 T cell response during the acute phase of Trypanosoma cruzi infection

ANA, YAMILE; ROJAS MARQUEZ, JORGE D.; FOZZATTI, LAURA; CERBAN, FABIO M.; STEMPIN, CINTHIA C.

Buenos Aires

Congreso; Reunión conjunta de sociedades de biociencia; 2017

Sociedad Argentina de Inmunología

We have shown that decreased CD4 T cell proliferation and reduced IFN-g production during acute phase of Trypanosoma cruzi infection is related to increase of inhibitory receptor PD-1 and gene related to anergy in lymphocytes (GRAIL) expression, reduced IL2 production and lower mTOR activation. As it has been demonstrated that is necessary the activation of anabolic metabolism and mitochondrial biogenesis for the transition from quiescence to growth and proliferation, the aim of this study was to evaluate wether this CD4 T cell dysfunction is related to metabolic alterations. BALB/c mice were infected i.p. with 500 trypomastigotes of Tulahuen strain and CD4 T cells were purified from spleen of uninfected (control) or infected mice at different points post infection (p.i). We evaluated expression of nutrient transporters CD71 (Transferrin), CD98 (aminoacids) and Glut1 (glucose) as well as uptake of a fluorescent glucose analog, 2NBDG by FACS. We did not observed differences in CD71, CD98 and Glut1 expression in ex vivo CD4 T cells from infected animals compared with controls. After stimulation, CD4 T cells from 21 p.i animals showed no differences compared to unstimulated cells. In contrast, CD4 T cells from control and 42 p.i animals were able to upregulate this transporters besides increase the uptake of 2-NBDG. To evaluate mitochondrial state in CD4 T cells we combined a potential-dependent (MitoOrange) and a potential-independent mitochondrial dye (MitoGreen) to identify CD4 T cells with depolarized mitochondria as well as mesured mitochondrial ROS (mROS) production (Mitosox) by FACS. At day 15 p.i. a significantly higher fraction of CD4 T cells had depolarized mitochondria compared with control or 42 p.i animals, concomitant with increased levels of mROS produced by CD4 T cells with high expression of PD-1. This results led as to consider PD-1 as a possible regulatory pathway of this metabolic dysregulation and mitochondrial depolarization with mROS production.