胰升糖素样肽1逆转细胞因子诱导胰岛β细胞的程序化细胞死亡因子5表达

Glucagon-like peptide-1 reverses the cytokines-induced expression of programmed cell death 5 gene in pancreatic β-cells

目的研究胰升糖素样肽1(GLP-1)对促炎性细胞因子诱导小鼠胰岛β细胞程序化细胞死亡因子5(PDCD-5)等凋亡相关分子表达的影响。方法小鼠NIT-1细胞株与细胞因子混合物加或不加GLP-1孵育24h后,采用膜联蛋白V(Annexin V)和碘化丙啶(PI)标记后进行流式细胞仪分析检测细胞凋亡,通过RT-PCR和Western blot检测PDCD-5、Fas、caspase 3等凋亡相关分子的表达。结果30U/ml白细胞介素1β(IL-1β)+100U/ml干扰素γ+100U/ml肿瘤坏死因子α使Annexin V单阳性细胞和Annexin V/PI双阳性细胞明显增多;与对照组相比,细胞因子处理组NIT-1细胞的PDCD-5、Fas及caspase 3 mRNA和蛋白的表达水平显著上调;10nmol/LGLP-1可逆转细胞因子的上述效应。结论促炎性细胞因子通过激活PDCD-5等凋亡信号通路导致胰岛β细胞凋亡,GLP-1对细胞因子所致的PD-CD-5表达和细胞凋亡具有抑制效应。

Objective To investigate the effects of glucagon-like peptide-1 （GLP-1） on the expression of apoptosis-related molecules including programmed cell death 5 （PDCD-5） gene in pancreatic β cells induced by proinflammatory cytokines, Methods Mouse islet β-cell line NIT-1 was incubated for 24 h with cytokine mixture （Mix） in the absence or presence of GLP-1. The apoptotic cells were assayed by flow cytometry after stained with annexin V-FITC and propidium iodide （PI）, The expressions of PDCD5,Fas, and caspase 3 were detected using reverse transcription-polymerase chain reaction （RT-PCR） and Western blot, Results The number of both annexin V single positive cells and annexin V/PI double positive cells significantly increased in the cells treated with 30 U/mL interleukin-1β （IL-1β） ＋ 100 U/mL interferon-γ （IFN-γ） ＋ 100 U/mL tumor necrosis factor-α （TNF-α）. The expressions of PDCD5, Fas, and caspase 3 at both mRNA and protein levels were upregulated in the cells exposed to the cytokines. The above-mentioned effects of the cytokines were reversed by 10 nmol/L of GLP-1, Conclusion These data show that the proinflammatory cytokines cause pancreatic β cell apoptosis via activation of PDCD5 signal pathway and that GLP-1 inhibits the upregulation of PDCD5 expression and the subsequent event of apoptosis induced by the cytokines.