MACROPHAGE M1/M2 POLARIZATION INDUCED BY LIPIDS FROM LEISHMANIA BRAZILIENSIS PROMASTIGOTES AND AMASTIGOTES

CARFAGNA, IVANNA E; BOTT, EMANUEL; LAMMEL, ESTELA MARÍA; GIMÉNEZ, GUADALUPE; BELAUNZARÁN, MARIA LAURA

Toledo

Congreso; 6th World Congress on Leishmaniasis; 2017

BackgroundInfections control depends on innate immunity activation and there is evidence of the immunomodulatory role thatpathogens´ lipids display in this process where macrophages play a key role, being classified into M1 (classical) andM2 (alternative) activationphenotypes. Control of Leishmania spp infection requires a pro-inflammatory profile withM1 macrophages; though the parasite has developed strategies to evade this response. In L. braziliensis, agent ofcutaneous Leishmaniasis, we found quantitative differences in the lipid profiles of promastigotes (PRO) andamastigotes (AMA), as well as after parasite disruption and incubation that generates bioactive lipids which maycontribute to inflammation. We here studied the effect of total lipids from PRO and AMA (intact and post-incubation)in lipid bodies? induction, ciclooxigenase-2 (COX-2) expression and macrophage M1/M2 polarization.2 MethodsL. braziliensis MHOM/BR/75M2904, PRO or AMA (1-3x108/ml) were lysed by 3 cycles of N2/37°C + proteaseinhibitors. Lipids were extracted following Bligh & Dyer, dried under N2 to constant weight and suspended in ethanol.Parasites were also incubated for 20 h at 37°C to allow lipids hydrolysis and then extracted and processed asmentioned (PROinc and AMAinc).Murine peritoneal macrophages (1x106/well) were stimulated with 50 μg/ml of thedifferent lipids for 24-48 h at 37ºC and 5% CO2 to determine: Lipid bodies formation (Gimenez et al, 2010), COX-2,inducible nitric oxide synthase (iNOS) and Arginase-1 expression by Immunoblot, Nitric oxide (NO) using Griessreaction (Shoda et al, 2000) and Arginase activity (Al-Mutairi MS et al, 2010).3 ResultsWe determined that PRO induced the highest Arginase-1 expression/activity, lower iNOS expression and NOproduction, suggesting an anti-inflammatory response with M2 macrophages. In contrast, AMAinc induced the highestiNOS expression and NO productionand lowerArginase-1 expression/activity, suggesting a pro-inflammatoryresponse, related to M1 macrophages. As concerns lipid bodies, all the lipids analyzed induced their generation,whereas the higher levels of COX-2 expression were obtained with AMAinc.4 ConclusionsThe results suggest that PRO, PROinc, AMA and AMAinc may differentially contribute to the modulation of theimmune response; this could be related to their different lipid profiles, thus bioactive lipids from L. braziliensis couldbe good candidates for immunoprophylactic strategies. Supported by CONICET/UBA