8月23日，国际知名学术期刊Molecular and Cellular Proteomics在线发表了生化细胞所曾嵘研究组工作：运用蛋白质组学策略，研究了大鼠肝脏线粒体蛋白质组表达、蛋白质磷酸化修饰以及羟基化修饰从前糖尿病期到糖尿病初期的动态变化。
已有研究表明，在2型糖尿病发病过程中，细胞线粒体的生理功能发生了显著变化，线粒体的功能受损也是进一步促进糖尿病发展的重要因素。了解糖尿病发病过程中线粒体蛋白质组及其修饰的动态变化，掌握这些变化所影响的生理活动和调控网络，对于阐明2型糖尿病的致病过程有着重要的意义。
中国科学院上海生命科学研究院生化与细胞研究所/系统生物学重点实验室博士生邓文君等人在曾嵘研究员的指导下，运用蛋白质组学策略和该实验室发明的阴阳多维色谱-质谱方法，研究了大鼠肝脏线粒体的蛋白质组表达、蛋白质磷酸化修饰以及羟基化修饰从前糖尿病期到糖尿病初期的动态变化。研究发现在2型糖尿病发病早期，肝细胞通过不断增强能量代谢，激活三羧酸循环、脂肪酸β氧化等物质代谢途径以适应不断升高的血糖和血脂。该工作发现这些代谢途径在糖尿病发生过程中不仅存在着蛋白质表达水平的调控，还存在着蛋白质磷酸化修饰水平的调控。此外，随着线粒体能量代谢的加强，其副产物活性氧物质（Reactive Oxygen Species，ROS）的含量也随之上升，对细胞形成氧化压力。该工作检测到线粒体蛋白质羟基化修饰水平随着糖尿病的进展而升高，这正是细胞氧化压力增强的一种体现。但另一方面，线粒体内抗氧化压力以及抗凋亡蛋白质的表达却随糖尿病的进展明显降低，进一步反映出随着2型糖尿病的发生，细胞清除氧化物质的能力降低，细胞凋亡指数不断上升。这一工作首次系统地揭示了糖尿病发生发展过程中肝脏线粒体各个功能模块在蛋白质表达水平，蛋白质磷酸化修饰水平和羟基化修饰水平的动态变化，这些变化相互影响、相互调节，最终促进了一种稳定病理状态-2型糖尿病的形成。这一工作为进一步研究2型糖尿病的致病机理，筛选糖尿病的诊断标志物和治疗靶点提供了分子基础。
该项工作得到了国家科技部，基金委，中科院和欧盟第六框架的经费支持。（生物谷Bioon.com）
生物谷推荐原始出处：
Mol. Cell. Proteomics, Aug 2009; doi:10.1074/mcp.M900020-MCP200
Proteome, phosphoproteome and hydroxyproteome of liver mitochondria in diabetic rats at early pathogenic stages
Wen-Jun Deng, Song Nie, JIe Dai, Jia-Rui Wu, and Rong Zeng
Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai 200031
It has been proposed that mitochondrial dysfunction is involved in the pathogenesis of type 2 diabetes (T2D). To dissect the underlying mechanisms, we performed a multiplexed proteomics study on liver mitochondria isolated from a spontaneous diabetic rat model before/after they are rendered diabetic. All together we identified 1091 mitochondrial proteins, 228 phosphoproteins and 355 hydroxyproteins. Mitochondrial proteins were found to undergo expression changes in a highly correlated fashion during T2D development. For example, proteins involved in ?-oxidation, TCA cycle, oxidative phosphorylation (OXPHOS) and other bioenergetic processes were coordinately up-regulated, indicating that liver cells confront T2D by increasing energy expenditure and activating pathways that rid themselves of the constitutively increased flux of glucose and lipid. Notably, activation of OXPHOS is immediately related to the overproduction of reactive oxygen species (ROS), which causes oxidative stress within the cells. Increased oxidative stress was also evidenced by our post-translational modification profiles, such that mitochondrial proteins were heavier hydroxylated during T2D development. Moreover, we observed a distinct depression of anti-apoptosis and anti-oxidative stress proteins, which might reflect higher apoptotic index under diabetic stage. We suggest that such changes in systematic metabolism are causally linked to the development of T2D. Comparing proteomics data against microarray data, we demonstrated that many T2D-related alterations were unidentifiable by either proteomic or genomic approaches alone, underscoring the importance of integrating different approaches. Our compendium could help to unveil pathogenic events in mitochondria leading to T2D, and be useful for the discovery of diagnosis biomarker and therapeutic targets of T2D.
