Li Linghai, Zhang Huina, Wang Weiyi, Hong Yun, Wang Jifeng, Zhang Shuyan, Xu Shimeng, Shu Qingbo, Li Juanfen, Yang Fuquan, Zheng Min, Qian Zongjie, Liu Pingsheng
Department of Anesthesiology, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing, China.
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
Sci Rep. 2016 Jan 22;6:19782. doi: 10.1038/srep19782.
Excessive retention of neutral lipids in cardiac lipid droplets (LDs) is a common observation in cardiomyopathy. Thus, the systematic investigation of the cardiac LD proteome will help to dissect the underlying mechanisms linking cardiac steatosis and myocardial dysfunction. Here, after isolation of LDs from normal and dysfunctional Sprague-Dawley rat hearts, we identified 752 heart-associated LD proteins using iTRAQ quantitative proteomic method, including 451 proteins previously unreported on LDs. The most noteworthy finding was the identification of the membrane resealing protein, dysferlin. An analysis of dysferlin truncation mutants indicated that its C2 domain was responsible for its LD localization. Quantitative proteomic results further determined that 27 proteins were increased and 16 proteins were decreased in LDs from post pressure overload-induced dysfunctional hearts, compared with normal hearts. Notably, adipose triacylglycerol lipase (ATGL) was dramatically decreased and dysferlin was substantially increased on dysfunctional cardiac LDs. This study for the first time reveals the dataset of the heart LD proteome in healthy tissue and the variation of it under cardiac dysfunction. These findings highlight an association between the altered LD protein localization of dysferlin and ATGL and myocardial dysfunction.
心脏脂质小滴（LDs）中中性脂质的过度潴留是心肌病中常见的现象。因此，对心脏LD蛋白质组进行系统研究将有助于剖析心脏脂肪变性与心肌功能障碍之间的潜在机制。在此，我们从正常和功能失调的Sprague-Dawley大鼠心脏中分离出LDs后，采用iTRAQ定量蛋白质组学方法鉴定了752种与心脏相关的LD蛋白，其中包括451种先前未在LDs上报道过的蛋白。最值得注意的发现是鉴定出了膜修复蛋白dysferlin。对dysferlin截短突变体的分析表明，其C2结构域负责其在LDs上的定位。定量蛋白质组学结果进一步确定，与正常心脏相比，压力超负荷诱导的功能失调心脏的LDs中有27种蛋白增加，16种蛋白减少。值得注意的是，在功能失调的心脏LDs上，脂肪甘油三酯脂肪酶（ATGL）显著减少，而dysferlin大量增加。本研究首次揭示了健康组织中心脏LD蛋白质组数据集及其在心脏功能障碍时的变化。这些发现突出了dysferlin和ATGL的LD蛋白定位改变与心肌功能障碍之间的关联。
