METFORMIN TREATMENT IN MACROPHAGES COULD HAVE AN EFFECT ON T CELL ACTIVATION AGAINST T. CRUZI INFECTION.

BAIGORRÍ, RE; HELLRIEGEL, MF; BRUGO, MB; VAZQUEZ VIGNALE, M; FONTANARI, C; VIANO, ME; RODRIGUEZ GALAN, MC; MOTRAN, CC; STEMPIN, CC; CERBAN, FM

San Luis

Congreso; LXXI Reunión Científica Anual de la Sociedad Argentina de Inmunología.; 2023

Sociedad Argentina de Inmunología.

Macrophages (Mo) play a key role in initial control of T. cruzi replication mainlythrough iNOS expression and ROS production. However, exacerbated ROS andiNOS production could lead to T cell suppression and tissue damage. This canbe modulated by various intracellular signals. AMPK is a cellular energy sensorresponding to low ATP levels and can be activated by Metformin (MF). MF is adiabetes drug that can modulate several pathways switching Mo activation. Wehave previously reported that pretreatment of bone marrow derived macrophages(BMDM) with MF prevents intracellular parasite replication and modulates theexpression of costimulatory and inhibitory molecules in peritoneal and spleenmacrophages of T.cruzi infected mice. To investigate the relevance of AMPK inPeritoneal Mo (PEMs) during T.cruzi infection, we determine the frequency of p-AMPK+ in Large PM (LPM) and Small PM (SPM) by Flow Cytometry (FC) fromBalb/c mice infected with 500 trypomastigotes (Tp) at different time points. Weobserved a significant decrease (p<0.01) of p-AMPK+ cells during the acutephase of infection that restored to normal levels in the chronic phase. As we showbefore, ex vivo treatment of PEMs from infected mice with MF (1 mM) decreasediNOS expression and NO production compared with PBS treatment. To confirmthese results, we performed an in vivo MF-treatment (100 mg/kg/day from day 5to 18 pi) on infected and control mice and we observed a significant decrease ofiNOS+ cells in LPM and SPM subsets and in spleen Mo assessed by FC. Wealso found less Foxp3+ CD4 T cells in peritoneal lavage from infected and MFtreatedmice, compared with the PBS-treated group (p<0.01). To investigate therole of Mo on T cell proliferation and Treg differentiation, we first co-cultured exvivo treated PEMs from infected or control mice with total splenocytes of controlanimals previously stimulated with PMA/Ionomycin. We found a reduction in Tcell proliferation by FC of stimulated CD4 and CD8 T cells in presence of infectedPEMs compared to non-infected PEMs. This reduction was significantly revertedwhen PEMs from infected cells were treated with MF (p<0.05). We also found anincrease in IFN-γ concentration by ELISA in the supernatant of these conditions,but we found no differences on Foxp3+ frequencies in this model. To study therole of Mo in MF treatment, we did an adoptive transfer of BMDM treated with MF(M-MF), PBS (M-PBS) or vehicle (PBS) to the peritoneum of infected mice at 14dpi. Four days later, we obtained peritoneal lavage, spleen and inguinal lymphnodes cells from these groups and non-infected (control) mice and evaluated thefrequency of Tregs by FC. The M-MF transfer reversed the increase in Tregfrequency produced by the M-PBS transfer and it is correlated with Tp bloodlevels since mice transferred with M-MF had less parasitaemia than M-PBStransferred. These results suggest that MF could modulate Mo response and itspotential role in T cell activation.