G蛋白偶联受体40在游离脂肪酸影响小鼠胰岛NIT-1细胞脂性凋亡中的作用  

Role of GPR40 mediates the effects of FFAs on lipoapoptosis in mouse β-cell line NIT-1

作　　者：张莹[1,2] 程桦[1] 罗招凡[1] 徐明彤[1] 张少玲[1] 黎峰[1] 严励[1] 李焱[1] 

机构地区：[1]中山大学附属第二医院内分泌科,广东广州510120 [2]广州医学院第三附属医院内分泌科,广东广州510150

出　　处：《中国病理生理杂志》2009年第7期1376-1380,共5页Chinese Journal of Pathophysiology

基　　金：广东省自然科学基金资助项目(No.06021329)

摘　　要：目的:探讨G蛋白偶联受体40(GPR40)是否介导游离脂肪酸(FFAs)对小鼠胰岛NIT-1细胞脂性凋亡的影响及其可能机制。方法:观察棕榈酸、油酸(500μmol/L,48h)对NIT-1细胞凋亡的影响,用Hoechst33342染色、TUNEL及流式细胞仪检测凋亡。并利用siRNA技术抑制GPR40在NIT-1细胞表达,观察棕榈酸、油酸对GPR40表达抑制细胞脂性凋亡的影响,行Western blotting观察Bcl-2、Bax和p-c-Jun表达。结果:棕榈酸长期作用可诱导NIT-1细胞凋亡;而油酸可抑制棕榈酸对NIT-1细胞的诱导凋亡作用。抑制GPR40表达后,空转组、control siRNA、GPR40 siRNA转染细胞分别予棕榈酸孵育48h,3组间细胞凋亡率差异无显著;3组细胞分别予棕榈酸、油酸共孵育48h,GPR40 siRNA转染细胞凋亡率明显高于空转组细胞,差异显著(P<0.05),Western blotting显示这一过程伴随c-Jun磷酸化水平下降、Bcl-2、Bax表达无明显变化。结论:GPR40未参与饱和脂肪酸诱导的β细胞凋亡,而介导了不饱和脂肪酸对脂性凋亡的抑制作用,c-Jun可能参与这一过程。提示GPR40参与调节β细胞适应性,为探讨肥胖和T2DM的关系提供了新的线索。AIM ： To evaluate the role of G protein - coupled receptor 40 （GPR40） mediates the effects of free fatty acids （FFAs） on lipoapoptosis in mouse β - ceil line NIT - 1 and the mechanisms involved in this process. METHODS： NIT- 1 cells were supplemented with palmitate （500 μmol/L） or oleate （500 μmol/L） for 48 h, then apeptosis of the cells was determined by the methods of Hoechst 33342, TUNEL and flow cytometry （Annexin V/PI）. The small interfering RNA technique was used to inhibit the expression of GPR40 in NIT - 1 cell. The mock, control siRNA and GPR40 siRNA transfected cells were either supplemented with palmitate （500 μmol/L） or co -incubated with palmitate and oleate （500μmol/L for each） for 48 h. The percentages of apoptotic cells were quantified. The expression＇of p -c -Jun, Bcl -2 and Bax were detected by Western blotting. RESULTS ： Palmitate induced 13 cell lipeapeptosis, whereas oleate inhibited NIT - 1 cells from palmitate - induced lipoapoptosis. No significant difference of the percentages of apeptotic cells was indicated among the mock, control siRNA and GPR40 siRNA transfected cells treated with palmitate （P 〉0. 05）. However, after coincubated with palmitate and oleate （500 μmol/L for each） for 48 h, the percentage of apoptotic cells in GPR40 siRNA transfected cells was greater than that in mock （ P 〈 0. 05 ）, while the expression of p - c - Jun was decreased. The expres- sions of Bci-2 and Bax were not affected. CONCLUSION： Palmitate induced 13 cell lipoapoptosis might not be mediated through GPR40, whereas oleate inhibits NIT - 1 cells from palmitate - induced lipoapoptosis, which is mediated at least in part through GPR40, the change of c - Jun expression may play an role in this process, suggesting that GPR40 might be implicated in the control of β cell mass plasticity and GPR40 probably provides a link between obesity and type 2 diabetes.

关 键 词：G蛋白偶联受体40 糖尿病 非胰岛素依赖型 游离脂肪酸 细胞凋亡 NIT-1细胞 

分 类 号：R363[医药卫生—病理学]