Analysing the role of wnt signaling in M1macrophage polarization

HERRERA MELISA; SOFIA VALLON TRABEKSI; JUAN NAHUEL QUIROZ; BELÉN BRUGO; XIMENA VOLPINI; CRISTINA MOTRÁN

Congreso; LXX Reunión anual de la Sociedad Argentina de Inmunología (SAI). 16-19 de noviembre. Mar del Plata. Buenos Aires Argentina; 2022

Wnt signaling pathways, in addition to participating in key cellularprocesses during organogenesis, plays an important regulatoryrole in infectious and inflammatory processes. The expression ofWnt proteins and the activation of the Wnt/β-catenin and Wnt/Ca++pathways are induced in macrophages (Mo) infected with T. cruzithrough TLR signaling. Notably, when both Wnt/b-catenin pathwayor the secretion of Wnt proteins are blocked using IWP-L6, the activity of arginase-1 (Arg-1) is inhibited, and Tc-infected Mo adoptsan M1-like phenotype. Our hypothesis is that the activation of Wntsignaling pathways in Mo would play a critical role in defining theactivation/polarization profile of these cells after activation by TLRligands. Thus, to investigate the role of Wnt signaling pathways inMo polarization to M1, J774 cells or bone marrow derived Mo weretreated with IWP-L6 or vehicle for 24 h and then stimulated withIFN-γ plus LPS (M1 stimulus). The production of NO, IL-6, IL-12and IL-1β was evaluated in culture supernatant and the expression of CD86, CD38 and Arg-1 determined by FACS at 48 h poststimulation. In addition, phagocytosis assay of heat-killed Candidaalbicans was assessed using light microscopy. Cells treated withIWP-L6 before the M1-polarizing stimulus showed a lower production of NO (p<0.001) and IL-6 (p<0.05) than control cells. However, they showed higher phagocytic capacity (p<0.001) and highersecretion of IL-12 (p<0.01) and IL-1β (p<0.05) than vehicle-treatedcells. As expected, the M1 stimulus increased the percentage ofcells expressing the M1 markers CD86+ CD38+ (p<0.01), while didnot induce Arg-1 expression. Interestingly, inhibition of Wnt signaling increased the percentage of Arg-1+ CD86- CD38- and Arg-1 +CD86+ CD38+ cell populations. Our results suggest that Wnt signaling participates in M1 polarization induced by classical stimulus bymodulating the expression of key molecules that contribute to thisphenotype