The activation of CD14, TLR4, and TLR2 by mmLDL induces IL-1β, IL-6, and IL-10 secretion in human monocytes and macrophages

Atherosclerosis is considered a chronic inflammatory disease in which monocytes and macrophages are critical. These cells express CD14, toll-like receptor (TLR) 2, and TLR4 on their surfaces, are activated by minimally modified low-density lipoprotein (mmLDL) and are capable of secreting pro-inflammatory cytokines. The aim of this research was thus to demonstrate that the activation of CD14, TLR2, and TLR4 by mmLDL induces the secretion of cytokines

Prolactin Levels Correlate with Abnormal B Cell Maturation in MRL and MRL/lpr Mouse Models of Systemic Lupus Erythematosus-Like Disease

Prolactin (PRL) plays an important role in modulating the immune response. In B cells, PRL enhances antibody production, including antibodies with self-specificity. In this study, our aims were to determine the level of PRL receptor expression during bone-marrow B-cell development and to assess whether the presence of high PRL serum concentrations influences absolute numbers of developing populations and disease outcome in lupus-prone murine models. We observed that the PRL-receptor is expressed in early bone-marrow B-cell; the expression in lupus-prone mice, which had the highest level of expression in pro-B cells and immature cells, differed from that in wild-type mice. These expression levels did not significantly change in response to hyperprolactinemia; however, populations of pro-B and immature cells from lupus-prone strains showed a decrease in the absolute numbers of cells with high PRL-receptor expression in response to PRL. Because immature self-reactive B cells are constantly being eliminated, we assessed the expression of survival factor BIRC5, which is more highly expressed in both pro-B and immature B-cells in response to PRL and correlates with the onset of disease. These results identify an important role of PRL in the early stages of the B-cell maturation process: PRL may promote the survival of self-reactive clones

Prolactin Rescues Immature B-Cells from Apoptosis Induced by B-Cell Receptor Cross-Linking

Prolactin has an immunomodulatory effect and has been associated with B-cell-triggered autoimmune diseases, such as systemic lupus erythematosus (SLE). In mice that develop SLE, the PRL receptor is expressed in early bone marrow B-cells, and increased levels of PRL hasten disease manifestations, which are correlated with a reduction in the absolute number of immature B-cells. The aim of this work was to determine the effect of PRL in an in vitro system of B-cell tolerance using WEHI-231 cells and immature B-cells from lupus prone MRL/lpr mice. WEHI-231 cells express the long isoform of the PRL receptor, and PRL rescued the cells from cell death by decreasing the apoptosis induced by the cross-linking of the B-cell antigen receptor (BCR) as measured by Annexin V and active caspase-3. This decrease in apoptosis may have been due to the PRL and receptor interaction, which increased the relative expression of antiapoptotic Bcl-xL and decreased the relative expression of proapoptotic Bad. In immature B-cells from MRL/lpr mice, PRL increased the viability and decreased the apoptosis induced by the cross-linking of BCR, which may favor the maturation of self-reactive B-cells and contribute to the onset of disease

IL-17-differentiated macrophages secrete pro-inflammatory cytokines in response to oxidized low-density lipoprotein

Abstract Background Cytokines and macrophages play a central role in the development of atherosclerosis. Interleukin (IL)-17 is a pro-inflammatory cytokine with differential effects on innate immune cells. We investigated the effects of IL-17 on macrophage differentiation and foam cell formation and activation in response to oxidized low-density lipoprotein (oxLDL). Methods Human monocytes were treated with IL-17 to induce macrophage differentiation. As controls, human monocytes were differentiated into M1 macrophages (M1) or M2 macrophages (M2). Subsequently, we analyzed the expression levels of markers such as CD80, CD36 and Toll-like receptors (TLRs) as well as foam cell formation and cytokines in M1, M2 and macrophages differentiated with IL-17 with or without oxLDL. Results The expression of M1 or M2 markers or cytokines was not induced in macrophages differentiated with IL-17. Macrophages differentiated with IL-17 formed few foam cells, with an average proportion of 20%, and expressed 3 times as much TLR2 and 3.8 times as much TLR4 as M0 macrophages. Additionally, macrophages differentiated with IL-17 acquired inflammatory capacity in response to oxLDL through the expression of specific markers, such as CD80, which increased 18-times compared with macrophages differentiated with IL-17 alone, and secreted 1.3 times less tumor necrosis factor (TNF)-α than M1. Additionally, oxLDL increased the levels of CD80, CD86 and IL-6 by 5.7, 2.8 and 1.4 times in M1 compared with M1 in the absence of oxLDL. In M2, oxLDL induced increases in the secretion of IL-6 and TNF-α that were 1.9 times and 1.2 times smaller, respectively, than those observed in M1. Conclusion Our study demonstrates that differentiation of macrophages with IL-17 does not induce the expression of markers or cytokines characteristic of M1 or M2 and these macrophages form few foam cells; however, the expression of TLR is increased. Moreover, these macrophages acquire the inflammatory capacity as evidenced by the expression of costimulatory molecules and secretion of pro-inflammatory cytokines in response to oxLDL. These findings suggest that the activation of macrophages differentiated with IL-17 by oxLDL contributes to the inflammatory process of atherosclerosis

Plan estratégico de comunicación interna, GREDA Comercial, S.A. de C.V.

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