Microparticles as Messengers of Communication Between Blood and Vascular Cells

描述（由申请人提供）：本RC 1资助申请响应挑战领域“04-临床研究”，特别是NHLBI挑战主题04-HL-103：“评估白细胞与血小板、红细胞和内皮细胞相互作用在心脏、肺和血液疾病发病机制中的作用。“一个重要的知识差距是血小板如何与其他血液和血管细胞沟通。对这一过程的了解可以改善疾病管理和生物标志物的开发。小的无核血小板不仅在止血方面，而且在影响数百万美国人的糖尿病和心血管疾病中起着开创性的作用。对血小板的进一步兴趣是由每年输注数百万单位的血小板这一事实推动的，有时会产生有害的后果。血小板现在也被认为是炎症的关键诱导物。我们的实验室发现，血小板大量表达转录因子过氧化物酶体增殖物激活受体-γ（PPAR？）而那个PPAR呢配体抑制血小板活化。配体激活的过氧化物酶体增殖体激活受体？是一种以前未被认识到的靶点，可减弱2型糖尿病或心血管疾病患者不需要的血小板活化。过氧化物酶激活受体？被认为是一种抗炎转录因子，也通过非核机制发挥作用。我们的团队最近发现，PPAR？从血小板中以微粒（MP）形式释放。MP是含有生物活性蛋白和介质的亚微米膜囊泡。PPAR？含有MP的蛋白被巨噬细胞吸收并抑制其功能。我们还发现，2型糖尿病患者产生的MP具有异常低水平的PPAR？并且很可能刺激炎症而不是抑制炎症。我们提出了总体挑战和假设，即PPAR？通过跨细胞机制影响其他细胞。为了在2年内完成这一挑战，我们组建了一支优秀的多学科团队，以完成2个目标。目的1：研究含有过氧化物酶体增殖物激活受体的血小板膜蛋白？并确定它们影响关键白色血细胞和血管细胞功能的能力。来自正常和2型糖尿病患者的纯化血小板将用于在受控条件下体外产生MP。我们将研究它们被吸收并影响血液单核细胞/巨噬细胞和血管内皮细胞的能力。因此，我们将确定一种新的细胞间通讯形式。遗传系统和临床前小鼠模型将用于研究PPAR？健康和疾病中含有血小板MP。目的2：发现和鉴定含有过氧化物酶体增殖物激活受体的多聚蛋白？在正常人和2型糖尿病患者的血液中。我们将确定血液中的细胞来源的过氧化物酶体增殖物激活受体？包含MP。虽然一些MP将是血小板来源的（目的1），但其他MP可能来自白色血细胞或血管内皮细胞。MPs和细胞来源的模式可以用作疾病和治疗反应的生物标志物。这一新的信息可以用来开发一种“人工MP”来提供PPAR？从而为糖尿病和心血管疾病的治疗提供了新的范例。2型糖尿病及其后果，特别是心血管疾病，影响着数百万美国人。该项目将研究称为血小板的小血细胞如何防止出血，与健康和2型糖尿病患者的其他血液和血管细胞沟通。血小板在受到刺激时，会释放出一小部分含有指令的细胞，其他细胞会接受这些指令，然后改变它们的行为。了解这种细胞间通讯的新方式将导致新的方法和生物标志物来检测疾病，并提供新的治疗方法来减少糖尿病和其他疾病的后果。 2型糖尿病及其后果，特别是心血管疾病，影响着数百万美国人。 该项目将研究称为血小板的小血细胞如何防止出血，与健康和2型糖尿病患者的其他血液和血管细胞沟通。血小板在受到刺激时，会释放出一小部分含有指令的细胞，其他细胞会接受这些指令，然后改变它们的行为。了解这种细胞间通讯的新方式将导致新的方法和生物标志物来检测疾病，并提供新的治疗方法来减少糖尿病和其他疾病的后果。

DESCRIPTION (provided by applicant): This RC1 grant application is responsive to Challenge Area "04-Clinical Research" and specifically to the NHLBI Challenge Topic 04-HL-103: "Assess the role of leukocyte interaction with platelets, erythrocytes, and endothelium in the pathogenesis of heart, lung, and blood diseases." A significant knowledge gap is how the platelet communicates with other blood and vascular cells. Knowledge of this process could lead to improved disease management and biomarker development. The small anucleate platelet plays a seminal role not only in hemostasis, but also in diabetes and cardiovascular disease which affect millions of Americans. Further interest in the platelet is fueled by the fact that millions of units of platelets are transfused each year, sometimes with deleterious consequences. Platelets are now also recognized as key inducers of inflammation. Our laboratory discovered that platelets abundantly express the transcription factor peroxisome proliferator activated receptor-gamma (PPAR?) and that PPAR? ligands dampen platelet activation. Ligand activated PPAR? is a previously unrecognized target that attenuates unwanted platelet activation in patients with type 2 diabetes or cardiovascular disease. PPAR? is viewed as an anti-inflammatory transcription factor, which also functions via non-nuclear mechanisms. Our team recently discovered that PPAR? is released from platelets in microparticles (MPs). MPs are submicron membrane vesicles that contain bioactive proteins and mediators. PPAR? containing MPs are taken up by and dampen macrophage function. We also discovered that type-2 diabetics produce MPs that have abnormally low levels of PPAR? and are likely to stimulate inflammation rather than inhibit it. We propose the overall challenge and hypothesis that PPAR? in MPs influences other cells by a transcellular mechanism. To complete this challenge in 2 years we assembled an outstanding multidisciplinary team to complete 2 aims. Aim 1: Investigate platelet MPs containing PPAR? and determine their ability to influence key white blood cell and vascular cell functions. Purified platelets from normal and type-2 diabetics will be used to generate MPs in vitro under controlled conditions. We will study their ability to be taken up and influence blood monocytes/macrophages and blood vessel endothelial cells. Thus, we will identify a new form of cell-cell communication. Genetic systems and a preclinical mouse model will be used to study the role of PPAR?-containing platelet MPs in health and disease. Aim 2: Discovery and characterization of MPs containing PPAR? in the blood of normal humans and those with type-2 diabetes. We will determine the cellular sources in blood of PPAR? containing MPs. While some MPs will be of platelet origin (Aim 1), others could come from white blood cells or vascular endothelial cells. The patterns of MPs and cell of origin could be used as a biomarker of disease and response to therapy. This new information could be used to develop an "artificial MP" to deliver PPAR? to cells of choice leading to a new therapeutic paradigm in diabetes and cardiovascular disease. Type-2 diabetes and its consequences, particularly cardiovascular disease, affect millions of Americans. This project will study how small blood cells called platelets, which prevent bleeding, communicate with other blood and vascular cells in healthy and type-2 diabetic individuals. Platelets, when stimulated, release small parts of themselves that contain instructions that other cells take up and which then change their behavior. Understanding this new way of cell to cell communication will lead to new methods and biomarkers to detect disease and to new ways of delivering therapy to reduce the consequences of diabetes and other diseases. PUBLIC HEALTH RELEVANCE: Type-2 diabetes and its consequences, particularly cardiovascular disease, affect millions of Americans. This project will study how small blood cells called platelets, which prevent bleeding, communicate with other blood and vascular cells in healthy and type-2 diabetic individuals. Platelets, when stimulated, release small parts of themselves that contain instructions that other cells take up and which then change their behavior. Understanding this new way of cell to cell communication will lead to new methods and biomarkers to detect disease and to new ways of delivering therapy to reduce the consequences of diabetes and other diseases.