In vivo inhibition of mTOR pathway during Trypanosoma cruzi infection polarizes macrophages towards a proinflammatory profile with mitochondrial ROS production

VAZQUEZ VIGNALE ME, BAIGORRI RE, HELLRIEGEL MF, STEMPIN CC, CERBÁN FM

Mar del Plata

Congreso; https://www.medicinabuenosaires.com/PMID/36368022.pdf; 2022

Macrophages (Mo) are able to internalize the parasite that causes Chagas disease, Trypanosoma cruzi. However, the parasite can evade the microbicidal systems of Mo by intracellular modulationof the mTOR pathway. Rapamycin (Rapa) treatment of Mo previous to infection is able to inhibit mTOR pathway and to polarize Mo towards a proinflammatory profile, characterized by NLRP3 inflammasome activation and mitochondrial ROS (mROS) production.The objective of this work was to validate these results in an in vivo model. For this, Balb/c mice were treated with i.p. injections of 10 μg of Rapa while the control group received only the vehicle. Then, mice were separated from each group to be used as control non infected (NI-Rapa or NI-vehicle) or to be infected i.p. with 500 trypomastigotes (I-Rapa or I-vehicle). Rapa was administered every 72 hours beginning three days before infection and ending at 18 dpi. Mice were sacrificed at 19 dpi, blood and peritoneal lavage were obtained. We did not observe significant differences in parasitemia in infected mice between I-Rapa and I-vehicle groups. Cells from the peritoneum were analyzed by FACS to study the small (SPM, CD11b+, F4/80 low) and large peritoneal Mo (LPM, CD11b+, F4/80 high) populations. We observed that infection induced changes in the frequency of these populations (85%-15% LPM-SPM in the NI-vehicle and 77%-23% in the I-vehicle groups) but Rapa-treatment did not modify the proportion of these cells. Then, mROS production, NLRP3 expression and 4EBP1 phosphorylation were evaluated in these Mo peritoneal populations by FACS. mROS production was increased in infected compared to uninfected groups, and in thosetreated with Rapa compared to the vehicle group. NLRP3 expression and a tendency to decrease in 4EBP1 phosphorylation were observed in Rapa treated groups. Thus, it is possible to concludethat in vivo Rapa treatment validates previously in vitro results without altering the frequency of SPM/LPM populations.