FFAR1介导PPARγ激动剂拮抗β细胞脂毒性损害的分子机制

It is the core pathway to block β cells lipotoxicity-induced damage for preventing and treating diabetes, but it still lacks of specific intervention to lipotoxicity. In our present study, we have found that down-regulating the expression of free fatty acid receptor-1 (FFAR1) can weaken the anti-lipotoxicity effect of PPARγ agonist Pioglitazone(Piog) on β cells. Our results indicate that FFAR1 might mediate the anti-lipotoxicity role of PPARγ agonist. In order to confirm the hypothesis above, this project is designed to set β cell lines as an object of research, use RNAi and gene overexpression to regulate gene expression, regulate protein activity by chemicals in functional protein level, and build the cell model of exogenous FFAR1 expression with FFAR1 negative cell lines for an in-depth study of the potential role of FFAR1 through the three steps as follows: at first, our project is planned to observe whether FFAR1 mediates the anti-lipotoxicity effect of Piog; and next, we will analyze whether the possible pathway mediated by FFAR1 is by way of regulating the activity and expression of PPARγ, inhibiting oxidative stress, and improving the expression of insulin-related genes such as PDX-1 and MafA; at last, we will further investigate whether the effect of FFAR1 is conducted by the PLC-IP3-Ca2+ pathway from the perspective of molecular mechanisms. This project is with the purpose of providing a new way or target for intervening in β-cell lipotoxicity damage.

阻断β细胞脂毒性损害始终是防治糖尿病的核心，但迄今缺乏靶向干预药物。我们前期研究发现下调游离脂肪酸受体1(FFAR1)表达将削弱PPARγ激动剂Pioglitazone(Piog)拮抗β细胞脂毒性的作用，推测FFAR1可能参与Piog的抗脂毒性机制。为此，本研究拟以胰岛β细胞系为研究对象，采用RNA干扰和基因过表达技术调控基因表达；运用干预制剂在功能蛋白层面直接调节蛋白活性；利用FFAR1阴性表达细胞构建外源性FFAR1表达细胞模型等手段，从以下三个层次深入剖析FFAR1的潜在作用：首先观察FFAR1是否介导Piog的抗脂毒性作用；接着分析FFAR1介导作用的可能途径是否通过调节核因子PPARγ表达及活性，抑制氧化应激，改善胰岛素相关基因MafA、PDX-1的表达；最后从分子机制角度探讨FFAR1发挥效应是否经PLC-IP3-Ca2+通路传导。以期为干预β细胞脂毒性损害提供新的途径或靶点。

阻断β细胞脂毒性损害始终是防治糖尿病的核心，但迄今缺乏靶向干预药物。我们前期研究发现下调游离脂肪酸受体1(FFAR1)的表达将削弱PPARγ激动剂Pioglitazone(PIO)拮抗β细胞脂毒性的作用，推测FFAR1可能参与Piog的抗脂毒性机制。为此，本研究以胰岛β细胞系为研究对象，采用RNA干扰和基因过表达技术调控FFAR1基因表达，观察FFAR1不同表达水平对PIO 抗脂毒性作用的影响及可能途径。结果显示：FFAR1可通过介导抗氧化应激参与PIO抑制β细胞脂性凋亡的作用，相关机制可能涉及到PLCγ-IP3-ERK1/2-PPARγ途径的活化。我们的研究结果不仅有助于区分FFAR1在脂毒性中扮演的角色，而且还为拮抗β细胞脂毒性的损害提供了实验证据，同时有助于了解PIO作为FFAR1的激动剂减弱胰岛β细胞脂性凋亡的相关分子机制。