Anti-WDR5 monoclonal antibody, clone FQS22450(C)

Prostaglandin I-2 (PGI(2)) analog is regarded as a potential candidate for treating asthma. Human myeloid dendritic cells (mDCs) play a critical role in the pathogenesis of asthma. However, the effects of PGI(2) analog on human mDCs are unknown, In the present study, circulating mDCs were isolated from six healthy subjects. The effects of PGI(2) analogs iloprost and treprostinil on cytokine production, maturation and T-cell stimulatory function of human mDCs were investigated. Tumor necrosis factor (TNF)-alpha and interleukin (IL)-10 were measured by enzyme-linked immunosorbent assay. The expression of costimulatory molecules was investigated by flow cytometry. T-cell stimulatory function was investigated by measuring interferon (IFN)-gamma, IL-13 and IL-10 production by T cells cocultured with iloprost-treated mDCs. Intracellular signaling was investigated by Western blot and chromatin immunoprecipitation. We found that iloprost and treprostinil induced IL-10, but suppressed TNF-alpha production in polyinosinic-polycytidylic acid (poly I:C)-stimulated mDCs. This effect was reversed by the I-prostanoid (IP), E-prostanoid (EP) receptor antagonists or intracellular free calcium (Ca2+) chelator. Forskolin, an adenyl cyclase activator, conferred a similar effect. Iloprost and treprostinil increased intracellular adenosine 3',5'-cyclic monophosphate (cAMP) levels, and iloprost also increased intracellular Ca2+. Iloprost suppressed poly I:C-induced mitogen-activated protein kinase (MAPK) phospho-p38 and phospho-activating transcription factor (ATF)2 expression. Iloprost downregulated poly I:C-induced histone H3K4 trimethylation in the TNFA gene promoter region via suppressing translocation of histone 3 lysine 4 (H3K4)-specific methyltransferases MLL (mixed lineage leukemia) and WDR5 (WD repeat domain 5). Iloprost-treated mDCs inhibited IL-13, IFN-gamma and IL-10 production by T cells. In conclusion, PGI(2) analogs enhance IL-10 and suppress TNF-alpha expression through the IP/EP2/EP4 receptors-cAMP and EP1 receptor-Ca2+ pathway. Iloprost suppressed TNF-alpha expression via the MAPK-p38-ATF2 pathway and epigenetic regulation by downregulation of histone H3K4 trimethylation. Online address: http://www.molmed.org doi: 10.2119/molmed.2011.00193

Myeloid-derived suppressor cells (MDSCs), which play an important role in tumor and inflammatory diseases, are divided into two subsets CD11b(+)Ly6C(hi)Ly6G(-) monocytic MDSC (Mo-MDSC) and CD11b(+)Ly6C(low/neg)Ly6G(+) polymorphonuclear MDSC (PMN-MDSC) with different immunosuppressive function. However, it is poorly understood the mechanism(s) to control differentiation of Mo-MDSCs and PMN-MDSCs. Here, we found that lnc-C/EBP beta may promote PMN-MDSC but impede differentiation of Mo-MDSCs in vitro and in vivo. We demonstrated that lnc-C/EBP beta mediated differentiation of MDSCs was through downregulating multiple transcripts such as IL4il. Lnc-C/EBP beta not only bound to C/EBP b isoform LIP to inhibit the activation of C/EBP b but also interacted with WDR5 to interrupt the enrichment of H3K4me3 mark on the promoter region of IL4i1. Data also imply that conserved homo lnc-C/EBP beta has a similar function with mouse lnc-C/EBP beta. Since MDSC subsets exert different suppressive function, lnc-C/EBP beta may be acted as a potential therapeutic target for inflammatory and tumor-associated diseases.