New insights into the protein aggregation pathology in myotilinopathy by combined proteomic and immunolocalization analyses
New insights into the protein aggregation pathology in myotilinopathy by combined proteomic and immunolocalization analyses
复制标题
DOI：
10.1186/s40478-016-0280-0
复制
发表时间：
2016-02-03
影响因子：
7.1
通讯作者：
Kley, R. A.
中科院分区：
文献类型：
--
作者：
Maerkens, A.;Olive, M.;Kley, R. A.
肌原纤维性肌病的特征是进行性肌肉无力和肌肉纤维中明显的异常蛋白质聚集。在大约10%的患者中，这种疾病是由编码肌动素的MYOT基因突变引起的。我们的研究的目的是破译蛋白质沉积的组成在肌硬肌病，以获得新的信息聚集病理。结果：15例肌直病患者的骨骼肌样本被纳入研究。通过激光显微解剖从肌肉切片中收集聚集体和对照样品，随后通过高度敏感的蛋白质组学方法进行分析，从而实现相对的蛋白质定量。共检测到1002种不同的蛋白。76种蛋白质在聚集体样品中表现出显著的过度代表性，其中包括66种新鉴定的聚集体蛋白质。z盘相关蛋白是最丰富的聚集成分，其次是肌层和细胞外基质蛋白，参与蛋白质质量控制和降解的蛋白，以及具有肌动蛋白动力学或细胞骨架运输功能的蛋白。通过免疫定位研究评估了40种代表性过高的蛋白质。这些分析证实了我们的质谱数据，并揭示了异常肌肉纤维中蛋白质积累的不同区域。将肌肌病的蛋白质组学分析数据与其他肌原性肌病亚型的结果进行比较，发现了一种特征性的聚集成分的基本模式，并鉴定出一种高度敏感和特异性的肌肌病诊断标志物。结论:我们的发现i)表明聚集体的主要蛋白质成分属于一个相互作用的蛋白质网络，ii)为肌直肌病中蛋白质降解的复杂调控提供了新的见解，这可能与新的治疗策略有关。iii)暗示毒性功能获得导致肌凝素阳性的蛋白质聚集和由亚细胞分布变化引起的功能丧失（z -盘肌凝素缺乏会损害肌原纤维的完整性）的组合，iv)证明蛋白质组学分析有助于蛋白质聚集性肌病的鉴别诊断。
Introduction: Myofibrillar myopathies are characterized by progressive muscle weakness and impressive abnormal protein aggregation in muscle fibers. In about 10 % of patients, the disease is caused by mutations in the MYOT gene encoding myotilin. The aim of our study was to decipher the composition of protein deposits in myotilinopathy to get new information about aggregate pathology.Results: Skeletal muscle samples from 15 myotilinopathy patients were included in the study. Aggregate and control samples were collected from muscle sections by laser microdissection and subsequently analyzed by a highly sensitive proteomic approach that enables a relative protein quantification. In total 1002 different proteins were detected. Seventy-six proteins showed a significant over-representation in aggregate samples including 66 newly identified aggregate proteins. Z-disc-associated proteins were the most abundant aggregate components, followed by sarcolemmal and extracellular matrix proteins, proteins involved in protein quality control and degradation, and proteins with a function in actin dynamics or cytoskeletal transport. Forty over-represented proteins were evaluated by immunolocalization studies. These analyses validated our mass spectrometric data and revealed different regions of protein accumulation in abnormal muscle fibers. Comparison of data from our proteomic analysis in myotilinopathy with findings in other myofibrillar myopathy subtypes indicates a characteristic basic pattern of aggregate composition and resulted in identification of a highly sensitive and specific diagnostic marker for myotilinopathy.Conclusions: Our findings i) indicate that main protein components of aggregates belong to a network of interacting proteins, ii) provide new insights into the complex regulation of protein degradation in myotilinopathy that may be relevant for new treatment strategies, iii) imply a combination of a toxic gain-of-function leading to myotilin-positive protein aggregates and a loss-of-function caused by a shift in subcellular distribution with a deficiency of myotilin at Z-discs that impairs the integrity of myofibrils, and iv) demonstrate that proteomic analysis can be helpful in differential diagnosis of protein aggregate myopathies.