解耦联蛋白3基因敲除对骨骼肌糖摄取的影响及其机制研究

Uncoupling protein 3 (UCP3) is a mitochondrial anion carrier protein with highly selective expression in skeletal muscle. Despite a great deal of interest, to date neither its molecular mechanism nor its biochemical and physiological functions are well understood. Based on its high degree of homology to the original UCP (UCP1), early studies examined a role for UCP3 in thermogenesis. However, evidence for such a function is lacking. Recent studies have led researchers to hypothesize that the function of UCP3 might be: 1) UCP3 mitigates reactive oxygen species (ROS) production, and 2) UCP3 is somehow involved in fatty acid (FA) translocation. Because the high expression of UCP3 in skeletal muscle and the important role of skeletal muscle in glucose metabolism, many studies have focused on the role of UCP3 in glucose metabolism. While the role of UCP3 in glucose metabolism still remains controversial. Our previous data demonstrated that the insulin sensitivity was improved in UCP3 KO mice. However, the mechanism needs further investigation. In the present study, we explored the effect of ablation of UCP3 on glucose uptake by measuring the glucose uptake of primary myotubes and skeletal muscles in UCP3 KO mice and tested the possible mechanism of insulin resistance improvement by measuring signaling pathway involved in glucose uptake, KATP channel currents and the concentration of intracellular calcium, ROS and ATP.

解耦联蛋白3（UCP3）是主要在骨骼肌表达的线粒体内膜质子转运蛋白。由于UCP3主要在骨骼肌表达，而骨骼肌是外周摄取葡萄糖的主要组织，因此越来越多的研究关注UCP3在糖代谢中的作用。本课题组前期研究发现UCP3基因敲除（KO）小鼠较野生型(WT)小鼠胰岛素敏感性增加，但其机制是否是KO小鼠骨骼肌的糖摄取增加尚未阐明。因此，在先前研究的基础上本研究拟开展（1）从WT及KO小鼠分离比目鱼肌及原代骨骼肌细胞，并观察其对葡萄糖的摄取，明确UCP3基因敲除对骨骼肌糖摄取的影响；（2）用western blot及IP等方法检测比目鱼肌及肌细胞中与糖摄取相关的信号通路的改变，并检测两种细胞线粒体膜电位、ATP敏感的钾离子通道及细胞内ROS、ATP、钙离子含量的改变，探讨UCP3基因敲除影响糖摄取的机制。明确UCP3在糖代谢中的作用，对进一步阐明线粒体在胰岛素抵抗中的作用，开发药物干预靶点，具有重要意义。