Jin Ming, Drwal Garry, Bourgeois Tran, Saltz Joel, Wu Haifeng M
Department of Pathology, The Ohio State University, College of Medicine and Public Health, Columbus, OH 43210, USA.
Proteomics. 2005 May;5(7):1940-52. doi: 10.1002/pmic.200401057.
Plasma microparticles (MPs) are spherical cell membrane fragments derived from either apoptotic or activated cells. Characterized by a rich phospholipid moiety and many protein constituents, MPs normally circulate in the blood and contribute to numerous physiological processes. In disease states, MPs derived from the injured organ likely contain valuable markers for determining the site, type, and extent of disease pathology. However, the basic protein characteristics of plasma MPs have yet to be described. In this study, MPs from a pooled plasma sample derived from 16 healthy donors, all of group A blood type, were prepared by ultracentrifugation. Flow cytometry confirmed that a majority of these MPs are smaller than 1 microm. Factor Xa generation assay revealed the presence of tissue factor activity in these MPs, confirming MPs' role in initiating blood coagulation. The MP proteome was analyzed by two-dimensional (2-D) gel electrophoresis performed in triplicate, and compared with a 2-D gel of pooled whole plasma and blood platelets. Overall, plasma MPs displayed distinct protein features and a greater number of protein spots (1021-1055) than that detected in whole plasma (331-370). Protein spots expressed in high abundance in the MP proteome were then excised and submitted for protein identity determination. This process provided protein identification for 169 protein spots and reported their relative protein quantities within the MP proteome. These 169 protein spots represented 83 different proteins and their respective isoforms. Thirty of these proteins have never before been reported in previous proteome analyses of human plasma. These results provide unprecedented information on the MP proteome and create a basis for future studies to understand MP biology and pathophysiology.
血浆微粒（MPs）是源自凋亡或活化细胞的球形细胞膜碎片。MPs具有丰富的磷脂部分和许多蛋白质成分，通常在血液中循环并参与众多生理过程。在疾病状态下，源自受损器官的MPs可能含有用于确定疾病病理部位、类型和程度的有价值标志物。然而，血浆MPs的基本蛋白质特征尚未得到描述。在本研究中，通过超速离心从16名均为A型血的健康供体的混合血浆样本中制备MPs。流式细胞术证实这些MPs中的大多数小于1微米。因子Xa生成测定显示这些MPs中存在组织因子活性，证实了MPs在启动血液凝固中的作用。通过一式三份进行的二维（2-D）凝胶电泳分析MP蛋白质组，并与混合全血浆和血小板的二维凝胶进行比较。总体而言，血浆MPs显示出独特的蛋白质特征，并且蛋白质斑点数量（1021 - 1055个）比全血浆中检测到的（331 - 370个）更多。然后切除在MP蛋白质组中高丰度表达的蛋白质斑点并提交用于蛋白质鉴定。该过程为169个蛋白质斑点提供了蛋白质鉴定，并报告了它们在MP蛋白质组中的相对蛋白质量。这169个蛋白质斑点代表83种不同的蛋白质及其各自的异构体。这些蛋白质中有30种在先前的人类血浆蛋白质组分析中从未被报道过。这些结果提供了关于MP蛋白质组的前所未有的信息，并为未来研究理解MP生物学和病理生理学奠定了基础。
