IN VIVO INHIBITION OF MTOR PATHWAY DURING TRYPANOSOMA CRUZI INFECTION POLARIZES MACROPHAGES TOWARDS A PROINFLAMMATORY PROFILE WITH MITOCHONDRIAL ROS PRODUCTION

MATIAS VAZQUEZ; BAIGORRÍ, RUTH ELIANA; MARÍA FLORENCIA HELLRIEGEL; CINTHIA STEMPIN; LO PRESTI M. SILVINA, RIVAROLA H. WALTER, FERNÁNDEZ ALICIA R, ENDERS JULIO E, LEVIN GLORIA, FRETES RICARDO, CERBAN FABIO M., GARRIDO VANINA V., PAGLINI-OLIVA PATRICIA A.

Congreso; REUNIÓN DE LA SOCIEDAD ARGENTINA DE INMUNOLOGÍA; 2022

Macrophages (Mo) are able to internalize the parasite that causesChagas disease, Trypanosoma cruzi. However, the parasite canevade the microbicidal systems of Mo by intracellular modulationof the mTOR pathway. Rapamycin (Rapa) treatment of Mo previousto infection is able to inhibit mTOR pathway and to polarizeMo towards a proinflammatory profile, characterized by NLRP3 inflammasomeactivation and mitochondrial ROS (mROS) production.The objective of this work was to validate these results in an in vivomodel. For this, Balb/c mice were treated with i.p. injections of 10μg of Rapa while the control group received only the vehicle. Then,mice were separated from each group to be used as control noninfected (NI-Rapa or NI-vehicle) or to be infected i.p. with 500 trypomastigotes(I-Rapa or I-vehicle). Rapa was administered every72 hours beginning three days before infection and ending at 18 dpi.Mice were sacrificed at 19 dpi, blood and peritoneal lavage wereobtained. We did not observe significant differences in parasitemiain infected mice between I-Rapa and I-vehicle groups. Cells fromthe peritoneum were analyzed by FACS to study the small (SPM,CD11b+, F4/80 low) and large peritoneal Mo (LPM, CD11b+, F4/80high) populations. We observed that infection induced changes in thefrequency of these populations (85%-15% LPM-SPM in the NI-vehicleand 77%-23% in the I-vehicle groups) but Rapa-treatment didnot modify the proportion of these cells. Then, mROS production,NLRP3 expression and 4EBP1 phosphorylation were evaluated inthese Mo peritoneal populations by FACS. mROS production wasincreased in infected compared to uninfected groups, and in thosetreated with Rapa compared to the vehicle group. NLRP3 expressionand a tendency to decrease in 4EBP1 phosphorylation wereobserved in Rapa treated groups. Thus, it is possible to concludethat in vivo Rapa treatment validates previously in vitro results withoutaltering the frequency of SPM/LPM populations.