Department of Endocrinology, Diabetes and Metabolism, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan.
Atherosclerosis. 2013 May;228(1):270-6. doi: 10.1016/j.atherosclerosis.2013.02.035. Epub 2013 Mar 13.
Despite the number of potential biomarker proteins for diabetes, very few of them have proven useful as clinically beneficial indicators, because of the technical difficulties associated with their identification among highly abundant serum proteins. We attempted to identify a protein with distinguishable expression in human diabetes.
We applied a highly efficient strategy for the purification of endogenous low abundance proteins from diabetic and non-diabetic serum samples. Extracted sera were fractionated by SDS-PAGE and protein bands were isolated and analyzed by mass spectrometry using an ion-trap mass spectrometer. The identities of the proteins were confirmed by western blotting and the serum levels evaluated.
A significantly upregulated protein in diabetic patients was identified as monomeric α2-macroglobulin. Its tetramer, another dominant circulating molecular form, was only marginally increased in diabetes.
Serum monomeric α2-macroglobulin is highly expressed in many diabetic subjects. It is identical to the human 'cardiac isoform of α2-macroglobulin' described in the literature, a well-known acute phase serum biomarker protein mechanistically involved in cardiac and atherosclerotic diseases.
尽管有许多潜在的糖尿病生物标志物蛋白，但由于在富含血清蛋白的样本中鉴定它们存在技术困难，只有极少数被证明可用作有临床益处的指标。我们试图鉴定一种在人类糖尿病中具有可区分表达的蛋白质。
我们应用了一种从糖尿病和非糖尿病血清样本中高效纯化内源性低丰度蛋白质的策略。提取的血清用 SDS-PAGE 进行分级，然后使用离子阱质谱仪对蛋白条带进行分离和分析。通过 Western 印迹验证蛋白质的身份，并评估其血清水平。
鉴定出糖尿病患者中一种显著上调的蛋白质为单体α2-巨球蛋白。其四聚体，另一种主要的循环分子形式，在糖尿病中仅略有增加。
血清单体α2-巨球蛋白在许多糖尿病患者中高度表达。它与文献中描述的人类“心脏同工型α2-巨球蛋白”相同，是一种众所周知的急性相血清生物标志物蛋白，在心脏和动脉粥样硬化疾病中具有机械作用。
