Microparticles as Messengers of Communication Between Blood and Vascular Cells

描述（由申请人提供）：本RC1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”。一个重要的知识缺口是血小板如何与其他血液和血管细胞交流。了解这一过程可以改善疾病管理和生物标志物的开发。小无核血小板不仅在止血中起着重要作用，而且在影响数百万美国人的糖尿病和心血管疾病中也起着重要作用。每年有数百万单位的血小板被输注，有时会产生有害的后果，这一事实进一步激发了人们对血小板的兴趣。血小板现在也被认为是炎症的关键诱导剂。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?）配体抑制血小板活化。配体激活PPAR？在2型糖尿病或心血管疾病患者中，是一种以前未被认识到的靶点，可减轻不必要的血小板活化。PPAR吗?被认为是一种抗炎转录因子，它也通过非核机制起作用。我们的团队最近发现PPAR？以微粒（MPs）的形式从血小板中释放出来。MPs是含有生物活性蛋白和介质的亚微米膜囊泡。PPAR吗?含有MPs的细胞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MPs PPAR水平异常低？可能会刺激炎症而不是抑制炎症。我们提出了PPAR？MPs通过跨细胞机制影响其他细胞。为了在两年内完成这一挑战，我们组建了一支优秀的多学科团队来完成两个目标。目的1：研究血小板MPs是否含有PPAR？并确定它们影响关键白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在受控条件下用于体外生成MPs。我们将研究它们被吸收和影响血液单核/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-细胞通讯形式。遗传系统和临床前小鼠模型将用于研究PPAR的作用。-在健康和疾病中含有血小板MPs。目标2：发现和鉴定含有PPAR的MPs ？在正常人和2型糖尿病患者的血液中。我们将确定PPAR在血液中的细胞来源。包含议员。虽然一些MPs可能来自血小板（Aim 1），但其他MPs可能来自白细胞或血管内皮细胞。MPs和细胞来源的模式可以作为疾病和治疗反应的生物标志物。这一新信息可用于开发一种“人工MP”来递送PPAR。选择细胞导致糖尿病和心血管疾病的新治疗模式。2型糖尿病及其后果，尤其是心血管疾病，影响着数百万美国人。该项目将研究被称为血小板的小血细胞如何在健康和2型糖尿病患者中与其他血液和血管细胞交流。血小板可以防止出血。血小板在受到刺激时，会释放出自身的一小部分，其中包含其他细胞接受的指令，然后改变它们的行为。了解这种细胞间通讯的新方式将带来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.