The Roles Of Vorinostat In The Regulation Of Dendritic Cells And Experimental Autoimmune Encephalomyelitis

Multiple Sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system. Recently, current drugs are all unsatisfactory。It is therefore necessary to develop new drugs. Experimental Autoimmune Encephalomyelitis (EAE) is an animal model of MS, and is well an important model of the basic research of autoimmune inflammatory reaction. Both MS and EAE are believed to be a myelin-specific CD4+T cell-mediated autoimmune degenerative disease. Major is closely related to TH1and TH17cells. Dendritic cells (DCs) are professional antigen-presenting cells (APC) and play a crucial role in the initiation of immune responses. Immature DCs (iDCs) are very proficient at antigen uptake, while the main function of mature DCs (mDCs) is to induce T cell activation. What’s more, cytokines produced by DCs are important in promoting the differentiation of TH1, TH2, TH17and regulatory T cells. Different T cell subtypes execute different physiological functions in corresponding diseases. According to their important role in the immune system, DCs are a potential therapeutic target for the control of autoimmune and inflammatory disease. Vorinostat is one of the histone deacetylase (HDAC) inhibitors that have been approved for the treatment of cutaneous T cell lymphoma. However, the effect of vorinostat on autoimmune diseases such as MS and EAE, remain incomplete. So, this is the main content of our research.Research objectives:We have evaluated the effects of vorinostat on human CD14+monocyte-derived DCs differentiation, mature, antigen uptake, T cells proliferation mediated by DCs and cytokines produced by DCs in vitro. Furthermore, our research examined the actions of vorinostat on EAE in vivo to characterize the role and cellular mechanism. In a word, this study explores a new therapy pathway for inflammatory diseases such as MS. Experiment contents and methods:In vitro, human CD14+monocytes were separated from Peripheral Blood Mononuclear Cells by using a magnetic separation column, and then differentiated to DCs and induced to mature. DCs were analyzed by FACS to explore expression of surface marker. Endocytosis of iDCs was determined by measuring the cellular uptake of FITC-dextran. Mixed-Lymphocyte Reaction assay T cells proliferation mediated by DCs. Real-time quantitative PCR was performed for cytokines produced by DCs. In vivo, mice were immunized with MOG to induce EAE, and vorinostat was intragastric administered. Meanwhile, mice were observed and clinical scores were assessed daily. Paraffin sections of Lumbar spinal cords were stained with H&E, Luxol fast blue, immunostained with anti-CD3and anti-F4/80. FACS was applied to detect the effect of vorinostat on spleen different T cell subtypes and DC in EAE.Experimental results:In vitro, data of FACS showed that vorinostat decreased expression of surface marker CD80, CD83, CD86and HLA-DR on iDCs and mDCs.Vorinostat inhibited DCs differentiation and maturation. Vorinostat impaired the endocytosis function of iDCs and mDCs induced allogeneic T cell proliferation. Furtermore, vorinostat restricts mRNA expression of TNF-a, IFN-y, IL-6, IL-12p35and IL-23p40in DCs.In vivo, vorinostat significant decreased disease incidence, mena clinical score, cumulative score and maximal score of EAE. H&E and luxol fast blue staining showed that lumbar spinal cords of vorinostat-treated mice exhibited smaller numbers of inflammatory cells and small areas of demyelination. And immunohistochemical evaluation suggested that the numbers of infiltrating T cells and macrophages were lower in vorinostat treated-mice. Vorinostat suppressed pathogenic TH1and TH17cells, and expression of costimulatory molecules of DC in EAE mice. These results were corresponded to the effect of vorinostat on human CD14+monocyte-derived dendritic cells.All in all, vorinostat suppresses human CD14+monocyte-derived DC differentiation, maturation, endocytosis and antigen uptake function. In addition, vorinostat ameliorates EAE occurrence and development by inhibiting immune inflammatory response in CNS, and suppressing DC and pathogenic TH1and TH17cells. Vorinostat has therapeutic effect on EAE. This study laid a theoretical foundation for the application of HDAC inhibitor vorinostat to treat inflammation related diseases such as multiple sclerosis.