ABSTRACT
Objective:To investigate the effect of miR-322-5p which targets Akt3 on Th17 differentiation in experimental autoimmune encephalomyelitis (EAE) interfered by interferon-β (IFN-β). Methods:The effect of IFN-β on EAE mice which were randomly divided into IFN-β group and PBS group was examine. The percents of Th17 in the two groups were compared by fluorescence activated cell sorting. The miRNA array was made to find different miRNAs between those two groups. MiR-322-5p was screened for further research. The target gene of miR-322-5p was predicted using softwares and the common predicted target gene Akt3 was got. The expression of Akt3 was detected after IFN-β intervention and miR-322-5p overexpression. The target relationship between Akt3 and miR-322-5p was verified by luciferase reporter assay. At last, the effect of Akt3 on Th17 differentiation was explored in vitro. Results:Compared to PBS group, the percent of Th17 was significantly downregulated, the expression of miR-322-5p was significantly upregulated and Akt3 was significantly downregulated in IFN-β group. The expression of Akt3 was obviously decreased after overexpressing miR-322-5p. Luciferase reporter assay showed that Akt3 was directly targeted by miR-322-5p. The percent of Th17 differentiation was greatly promoted by Akt3 in vitro. Conclusion:IFN-β significantly ameliorates the severity of EAE by affecting miR-322-5p which can inhibit Th17 differentiation by targeting Akt3.
ABSTRACT
Myeloid-derived suppressor cells ( MDSC) are a bone marrow-derived heterogeneous cell population with immuno-suppressive activity.Although there is convincing evidence that autoimmune diseases are associated with MDSC expansion ,controversies remained regarding the role of MDSCs in controlling autoimmune responses .Recent studies have shown that the expansion of MDSCs , which are capable of inhibiting effector cell function in vitro ,does not always lead to alleviation of autoimmune diseases ,and in some ca-ses paradoxically exacerbates the disease progression .This review summarizes recent insights into the role of MDSCs in the development of autoimmune responses and the potential of using MDSCs for the treatment of autoimmune diseases .
ABSTRACT
Lung fibrosis is a life-threatening disease caused by overt or insidious inflammatory responses. However, the mechanism of tissue injury-induced inflammation and subsequent fibrogenesis remains unclear. Recently, we and other groups reported that Th17 responses play a role in amplification of the inflammatory phase in a murine model induced by bleomycin (BLM). Osteopontin (OPN) is a cytokine and extracellular-matrix-associated signaling molecule. However, whether tissue injury causes inflammation and consequent fibrosis through OPN should be determined. In this study, we observed that BLM-induced lung inflammation and subsequent fibrosis was ameliorated in OPN-deficient mice. OPN was expressed ubiquitously in the lung parenchymal and bone-marrow-derived components and OPN from both components contributed to pathogenesis following BLM intratracheal instillation. Th17 differentiation of CD4+ alphabeta T cells and IL-17-producing gammadelta T cells was significantly reduced in OPN-deficient mice compared to WT mice. In addition, Th1 differentiation of CD4+ alphabeta T cells and the percentage of IFN-gamma-producing gammadelta T cells increased. T helper cell differentiation in vitro revealed that OPN was preferentially upregulated in CD4+ T cells under Th17 differentiation conditions. OPN expressed in both parenchymal and bone marrow cell components and contributed to BLM-induced lung inflammation and fibrosis by affecting the ratio of pathogenic IL-17/protective IFN-gamma T cells.
Subject(s)
Animals , Mice , Bleomycin , Bone Marrow Cells , Fibrosis , Inflammation , Interleukin-17 , Lung , Osteopontin , Pneumonia , Pulmonary Fibrosis , T-Lymphocytes , T-Lymphocytes, Helper-InducerABSTRACT
Myeloid-related protein (MRP)8/MRP14 is an endogenous Toll-like receptor 4 (TLR4) ligand and is abundant in synovial fluid (SF) of rheumatoid arthritis (RA) patients. Belonging to damage-associated molecular patterns, it amplifies proinflammatory mediators and facilitates a wide range of inflammatory and autoimmune diseases. Interleukin (IL)-17-producing T-helper (Th)17 cells have a crucial role in RA pathogenesis, and IL-6 is the key factor promoting Th17 differentiation. We investigated whether the level of MRP8/MRP14 is positively associated with IL-6 and IL-17 levels in RA SF and found that MRP8/MRP14 level had a significant correlation with IL-6 and IL-17 levels in RA SF. We also observed that MRP8-induced IL-17 production by peripheral blood mononuclear cells but MRP14 did not. Upon stimulation with MRP8, IL-6 production was enhanced by RA fibroblast-like synoviocytes (FLS) and was further elevated by coculturing RA FLS with activated CD4+ T cells. Moreover, we demonstrated that MRP8-activated IL-6 production by RA FLS promoted differentiation of Th17 cells using the coculture system consisting of CD4+ T cells and RA FLS. In addition, IL-6 blockade attenuated Th17 polarization of CD4+ T cells in the cocultures. Inhibitor studies revealed that MRP8 increased IL-6 production in RA FLS via TLR4/phosphoinositide 3-kinase/nuclear factor-kappaB and mitogen-activated protein kinase signaling pathways. Our results show that MRP8 has a crucial role in stimulating IL-6 expression by RA FLS, and subsequently promotes Th17 differentiation in RA, suggesting that neutralizing MRP8 level in RA synovium may be an effective therapeutic strategy in RA treatment.