Apoptosis Mechanism Of INS-1E Cell Mediated By IL-1β And IFNγ

Objective:Apoptosis mechanism research of INS-1E cell mediated by inflammatorycytokines (IL-1β plus IFNγ)Methods:The content of IL-1βand IFNγ were measured in the serum from both diabeticpatients and matched healthy group; INS-1E cell viability and morphology wereevaluated by MTT and microscope respectively after IL-1β plus IFNγ treatment;Protein phosphorylation, expression and distribution were explored by western andimmunostaining before and after exposure to inflammatory cytokines. TCTPoverexpression and knockdown in INS-1E cells were achieved by adenovirusinfection and the roles of TCTP in inflammatory cytokines-induced apoptosis werefurther studied and analyzed.Results：Compared with control group, the level of IL-1β and IFNγ was higher in diabeticpatients serum; IL-1β plus IFNγ treatment could induce INS-1E cell apoptosis; TCTPexpression decreased whereas the content of p53and cleaved caspase3increasedafter inflammatory cytokines exposure. At the same time, the levels of anti-apoptoticbcl-2proteins, such as Bcl-2, Bcl-xl and Mcl-1, decreased simultaneously by IL-1βplus IFNγ treatment. Furthermore, inflammatory cytokines promoted Bax, thepro-death Bcl-2family number, to translocate to mitochondria. TCTP overexpressionantagonized the apoptotic effect of inflammatory cytokines, however, INS-1E cellsshowed more vulnerable to the cytokines when TCTP was knockdown by its shRNA.Conclusion:Abnormal high level of IL-1βand IFNγ can induce islet βcell apoptosis, whichclosely relates to the development of diabetes.INS-1E stimulated by inflammatory cytokines which in turn inactivatespro-survival bcl-2family members and favors the translocation of bax tomitochondria, leading to the intrinsic pathway of apoptosis.