SAHA Affect Maturation And Function Of Human Dendritic Cells Through Inhibiting NF-κB Signal Pathway

Background Histone deacetylase inhibitors (HDACIs) are a new class of anticancer drugs, but people are more concerned about the anti-tumor effect of ignoring the role of other fields. In fact, with the development of research, people find it also has great prospects in the treatment of inflammatory,autoimmune disease and transplant related diseases. SAHA(suberoylanilide hydroxamic acid) is one of the most thoroughly studied HDACIs.It can effectively inhibit type I and type Ⅱ HDACS and induce acetylation of histone increases, cause cancer cells to the process of transcription abnormalities and inducing cell cycle arrest,differentiation and apoptosis. However, the current research on SAHA is limited to the anti-tumor field. SAHA’S function on the immune regulation especially in the field of transplantation immunology is poorly understood. Investigating the role of SAHA in immune regulation will help us make better use of this medicine and fully know its double effects of anti-tumor and immune regulation, which will bring new attempt in the treatment of transplant rejection,graft versus host disease(GVHD) and other diseases.Objective The study was aimed to investigate the effect of SAHA on the maturation and function of human dendritic cells and to explore the underlying mechanism.Methods Peripheral blood mononuclear cells (PBMCs) were isolated from human peripheral blood and assigned to experimental group, each group of PBMC after adherent treatment and then cultured for6days in10%of heat-inactivated fetal bovine serum (FBS) RPMI1640medium supplemented with the GM-CSF (100ng/mL) and IL-4(500U/mL) every3days.Mature DC were induced by LPS (100ng/mL), FACS flow cytometry was used to detect the purity of these dendritic cells. In the LPS induced maturation process, dendritic cells treated with SAHA(group LPS+SAHA) or not(group LPS) were observed under inverted microscope. Flow cytometer was used to detect the surface antigen expressed by SAHA treated(group LPS+SAHA) or untreated DC(group LPS). The mixed lymphocyte culture (MLC) was used to observe the allogeneic lymphocyte stimulation. The NF-κB signaling pathway affected by SAHA was detected by electrophoretic mobility shift assay (EMSA).Results The Result Indicates that the volume of DC after LPS treatment becomes very large and like "dendritic" but the DC treated with SAHA(group LPS+SAHA) and LPS (group LPS) are small and don’t have the "dendritic change". Compared to the control, SAHA treatment led to a significantly down regulation of CD80, CD83and HLA-DR (P<0.01), the ability to stimulate the proliferation of lymphocytes was significantly lower than the control group (P<0.01). EMSA results showed that after SAHA treatment, NF-κB activity decreased, and was significantly lower than that of single LPS group.Conclusions It is concluded that SAHA can be effectively suppressed DC maturation and also weaken the DC to stimulate allogeneic T lymphocyte activation. NF-κB activation was blocked in the process shows it plays an important role in regulating DC differentiation...