The Protective Mechanism Of HDACi On The Apoptosis Of Islet ? Cells Induced By Inflammatory Cytokines

Histone deacetylases(HDACs)can regulate various biological processes by affecting the post-translational modification.Histone deacetylase inhibitor(HDACi)can induce the apoptosis of some tumor cells,and its mechanism of action has also been widely researched.For Type I diabetes mellitus(T1DM),which is also accompanied with inflammatory responses as tumors,it is less likely to be investigated whether HDACi can inhibit the inflammatory response in T1 DM and protect islet beta cells.Some studies have shown that the three cytokines IL-1?,TNF-?,and IFN-?are all related to T1 DM.Therefore,we hypothesized that HDACi can inhibit the apoptosis of INS-1 cells which is induced by the mixture of three cytokines.In this study,we selected three cytokines IL-1?,TNF-? and IFN-?.The cells were treated with different concentrations of inflammatory cytokines for 24 hours.The results showed that the mixture can inhibit the viability of INS-1 cells and induce cells' apoptosis.It was determined that the treatment time of mixture is 24 hours,and the subsequent experimental concentrations were IL-1?(10 ng/ml),TNF-?(12.5ng/ml),and IFN-?(25 ng/ml).Then we chose 8 HDACis.And we investigate whether 8 HDACis can protect INS-1 cells,increase cell viability,reduce apoptosis and reduce the protein associated with apoptosis induced by inflammatory factors through MTT assay,flow cytometry and Western blot.The protection time of HDACi was set to 0h,2h,4h,and 6h.The results showed that the longer pretreatment time of HDACi led to the more effective the protective effect,which enabled the cell viability to be higher and the amount of apoptosis cells to be less.One kinds of HDACi,M344,with the best protection were selected.Finally,we extracted the RNA of Cot group(cytokines mixture processing 0h,2h,8h,16 h,24h)and M344 group(mixture processing the same time and M344 preprocess 6h).Then we carried out the gene chip assay.At first,we compared thegene expression with 0h and 24 h in Cot group.And 2550 differentially expressed genes were obtained.We put them into pathway,and the results showed that the mixture of cytokines could up-regulate the expression of various apoptotic genes and block the cell cycle.Then we compared the Cot group with the M344 group which cells were treated by cytokines at the same time.Compared with the Cot group,M344 could reduce the expression of apoptotic genes at all times.It could also reduce the expression of immune related genes.But maybe it couldn't influence the cell cycle.In summary,in this paper we verified that the mixture of three cytokines can induce apoptosis in INS-1 cells.And one kind of HDACi,M344,was selected that could inhibit the action of cytokines to protect INS-1 cells.And the results show that the three cytokines could promote apoptosis and block cell cycle in INS-1cells.M344 could reduce the expression of various apoptosis and immune-related genes induced by cytokins.