Efeito da migalina sobre a resposta inflamatória provocada por monofosforil lipídio A (MFLA), agonista de TLR4, na linhagem Raw 264.7

Abstract

Macrophages are important cells of the immune system that play a role in innate and adaptive immune responses. They can differentiate into M1 and M2 subpopulations that display distinct functions in response to different stimuli. Toll-like receptors are fundamental in recognizing molecules associated with pathogens, as they activate macrophages and the innate immune response. The use of toll-like receptor activating molecules has been studied as a potential for new adjuvants, among these molecules Monophosphoryl lipid A (MPLA) stands out, a detoxified derivative of Lipid A, the main component of LPS (TLR4 agonist). Mygalin is a synthetic acylpolamine, analogous to the spermidine polyamine, originating from hemocytes of the spider Acanthoscurria gomesiana. This molecule has proven microbicide activity and does not cause cytotoxicity in eukaryotic cells. Mygalin binds to E. coli LPS and regulates the overproduction of pro-inflammatory cytokines in response to LPS. MPLA is one of the detoxified LPS subunits and has been used as an adjuvant. We investigated, using in vitro assays, the immunomodulatory character of Mygalin on the inflammatory response induced by the activation of macrophages of the Raw 264.7 cell line in response to MPLA, to define the contribution of this subunit in the suppression of the response to LPS. LPS and IFN-γ were used in parallel and possible mechanisms of this immune regulation were explored. We investigated, using in vitro assays, the immunomodulatory character of Mygalin on the inflammatory response induced by the activation of macrophages of the Raw 264.7 cell line in response to MPLA, to define the contribution of this subunit in the suppression of the response to LPS. LPS and IFN-γ were used in parallel and possible mechanisms of this immune regulation were explored. Our results showed that Mygalin did not induce NO synthesis in macrophages stimulated with both MPLA and LPS and suppressed the synthesis of cytokine IL-6 and chemokine CCL2 in cells stimulated with these TLR4 agonists. The contribution of the arginase activation pathway in NO suppression was also evaluated using NOHA as an inhibitor, the direct action of this enzyme in reducing NO synthesis was not proven.