Efeito das fosfatidilcolinas do líquido surfactante na modulação da atividade inflamatória e fagocítica de macrófagos alveolares

Abstract

Gram-negative bacteria, such as Klebsiella pneumoniae, have LPS in their membranes, a component that triggers inflammatory process, by cells of the host immune system such as macrophages (MA), produced cytokines, chemokines and lipid mediators. Inflammation is important in preventing microorganisms, but the exacerbation can cause serious tissue damage. Indeed, MA are also important in the control of infections, phagocytosis and death of microorganisms. Membrane lipids have been the subjects of studies to development of new pharmacological therapies (Membrane Lipid Therapy - MLT). On this way, lipid of surfactant liquid (LS) were target to development pulmonary MLT. Among the most abundant phospholipids in LS, we found POPC, a phosphatidylcholine (PC), the oxidized phospholipids product, such as PaldoPC. In this work, our aim was to evaluate the effects of LS-derived PCs on modulation of polarization (M1 and M2), inflammatory and phagocytic activity of macrophages against K. pneumoniae. Our results demonstrated that POPC and PaldoPC increase NO production when M1 are stimulated with LPS. Indeed, the treatment with PC increased the production of inflammatory cytokines and chemokines in the M0 and M1 profile, post LPS-stimulated. The increment on inflammatory mediators production by MA treated with PC, correlated with the increased on gene expression of TLR2, TLR4, and MYD88. The treatment with POPC increased phagocytosis of K. pneumoniae, corroborating with the increased production of PGD2. However, PaldoPC inhibited the phagocytosis and increased the production of PGE2. Our data suggest that PC did not have inflammatory effect direct on MA, but increased the MA response against LPS, increasing expression of innate immune receptors, and modulation of prostaglandins production; influenced the pulmonary microenvironment immune response.