Tissue Factor, Flow, and Platelet Adhesion/Aggregation on Activated Endothelium

活化内皮上的组织因子、血流和血小板粘附/聚集

• 批准号: 7465832
• 负责人: Eric Franklin Grabowski
• 金额: $ 41.99万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-15 至 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7465832
• 关键词: Adhesions; Adhesives; Affect; Antibodies; Antiphospholipid Antibodies; Apoptosis; Appearance; Arteries; Attention; Bacterial Toxins; Beds; Binding; Blood; Blood Platelets; Blood Vessels; Blood flow; Cell Adhesion Molecules; Cell membrane; Cell secretion; Cell surface; Cells; Cessation of life; Childhood; Cleaved cell; Coagulation Process; Collagen; Coma; Condition; Coronary artery; Culture Media; Deposition; Disease; Disruption; Down-Regulation; Endopeptidases; Endothelial Cells; Endothelium; Enhancers; Ensure; Epidemic; Epithelial Cells; Escherichia coli; Escherichia coli EHEC; Factor VIIa; Fibrin; Fibrinogen; Fostering; Glass; Glycosylphosphatidylinositols; Hemolytic-Uremic Syndrome; Hour; Human; Image; Impairment; Incubated; Inflammatory; Integrin beta3; Integrins; Intercellular adhesion molecule 1; Interruption; Intestines; Kidney; Kidney Failure; Lead; Leukocytes; Link; Localized; Measurement; Mediating; Membrane; Messenger RNA; Modeling; Necrosis; Organ; P-Selectin; Pathway interactions; Peptide Hydrolases; Phenotype; Phosphatidylserines; Phospholipids; Play; Process; Production; Proteins; Public Health; Range; Rate; Recombinants; Relative (related person); Reporting; Resolution; Role; Route; Seizures; Selectins; Shiga Toxin; Shiga-Like Toxin I; Site; Slide; Stress; Surface; System; TFPI; TNF gene; Testing; Therapeutic; Therapeutic Intervention; Thick; Thrombin; Thromboplastin; Thrombosis; Thrombus; Tissues; Toxin; United States; Up-Regulation; Vascular Endothelium; Video Microscopy; Vitronectin Receptors; Whole Blood; Work; arteriole; cell injury; cytokine; digital; exposed human population; foodborne; granulocyte; in vitro Model; in vivo; inhibitor/antagonist; mRNA Stability; monolayer; oxidized low density lipoprotein; receptor; research study; shear stress; von Willebrand Factor

DESCRIPTION (provided by applicant): In vivo, platelet adhesion/aggregation on activated endothelium may proceed via upregulation of endothelial cell (EC) molecules adhesive for platelets, especially 1v23 (the vitronectin receptor), ICAM-1, P-selectin, and ultra large von Willebrand factor (vWF) strings, accompanied and followed by tissue factor (TF)-driven mural platelet thrombosis in arteries or arterioles. The necessary EC activation may arise via several routes, including oxidized low density lipoproteins, bacterial toxins, and/or cytokines. The present work will test the hypothesis and paradigm that upregulation of these adhesion molecules permits the initiation of platelet adhesion/aggregation on endothelium, a process which is then amplified by both EC-associated TF and blood- borne TF. Blood-borne TF exists in the form of microparticles derived from leukocytes, platelets, and ECs. Upregulation of the EC-associated type of TF may take place by a variety of mechanisms, studied here: a) increases in TF mRNA stability and/or decreases in TFPI mRNA stability, b) enhancement of phosphatidylserine on the EC membrane outer leaflet, and c) reduction in the regulatory ability of EC-associated TFPI. We further hypothesize that mural platelet thrombi, in turn, slow blood flow sufficiently to allow activated endothelium to assume an even more procoagulant phenotype. A prime example of this paradigm is the epidemic childhood hemolytic uremic syndrome (HUS), in which food-borne, Shiga toxin (STX)-producing E. coli lead to a systemic inflammatory and prothrombotic state, with complications which can include renal failure, seizures, coma, and death. In an in vitro model of HUS we have demonstrated that STX significantly augments functional TF on monolayers of human glomerular ECs (HGECs), and markedly enhances platelet strings (associated with ultra large vWF strings) and small aggregate formation on these monolayers. Specific Aim 1 is to determine the mechanism(s) of TF augmentation observed with exposure of activated HGECs to STX. Specific Aim 2 is to demonstrate that STX augments platelet adhesion/aggregation in flowing blood on activated HGECs via upregulation of the above adhesion molecules, but also via upregulation of the TF pathway. These studies should elucidate the potential of therapeutic interventions in HUS directed at blocking adhesion molecules and blocking EC surface and/or blood-borne TF. PUBLIC HEALTH RELEVANCE: We will test the hypothesis that the presence of certain molecules on vascular endothelium (the blood vessel wall) which are adhesive for blood platelets are what initiates platelet thrombus formation on the inflamed blood vessel wall. This thrombus formation is then amplified by the clotting activity known as tissue factor, expressed on the surface of this same inflamed endothelium. A prime application of this hypothesis, we believe, is the epidemic childhood hemolytic uremic syndrome (HUS), in which food- borne toxin-producing E. coli leads to a disease state with complications including kidney failure, seizures, coma, and death. Our studies promise to clarify the potential of treatments for HUS directed at blocking the above adhesive molecules and vessel wall tissue factor.

描述(申请人提供)：在体内，血小板在激活的内皮细胞上的黏附/聚集可能是通过上调内皮细胞(EC)对血小板的黏附分子，特别是1v23(玻璃体连接素受体)、ICAM-1、P-选择素和超大von Willebrand因子(VWF)串，伴随和紧随着组织因子(TF)驱动的动脉或小动脉壁性血小板血栓形成。必要的EC激活可能通过几种途径发生，包括氧化型低密度脂蛋白、细菌毒素和/或细胞因子。目前的工作将检验这一假设和范式，即上调这些黏附分子可以启动内皮细胞上的血小板黏附/聚集，这一过程随后被EC相关的TF和血源性TF放大。血源性转铁蛋白以来源于白细胞、血小板和内皮细胞的微粒形式存在。EC相关类型的转铁蛋白的上调可能通过多种机制发生，这里研究：a)增加TF mRNA的稳定性和/或降低TFPI mRNA的稳定性，b)增强EC膜外叶上的磷脂酰丝氨酸，以及c)降低EC相关的TFPI的调节能力。我们进一步假设，壁性血小板血栓反过来会使血流变慢，从而使激活的内皮细胞呈现出更促凝血的表型。这种模式的一个主要例子是流行的儿童溶血性尿毒症综合征(HUS)，在这种综合征中，食源性产生志贺氏毒素(STX)的大肠杆菌会导致全身炎症和血栓前状态，并发症可能包括肾功能衰竭、癫痫发作、昏迷和死亡。在HUS的体外模型中，我们已经证明STX显著增加了人肾小球内皮细胞(HGECs)单层上的功能性转铁蛋白(Tf)，并显著促进了血小板串(与超大vWF串相关)和这些单层上的小聚集形成。特异目的1是确定STX作用下活化的HGEC的转铁蛋白升高的机制(S)。特异目的2是证明STX通过上调上述黏附分子，也通过上调TF途径，增加流动血液中活化的HGECs上的血小板黏附/聚集。这些研究应该阐明针对黏附分子和EC表面和/或血源性转铁蛋白的HUS治疗干预的可能性。与公共卫生相关：我们将检验这样一种假设，即血管内皮细胞(血管壁)上存在与血小板粘连的某些分子是导致炎症的血管壁上形成血小板血栓的原因。血栓的形成随后被称为组织因子的凝血活性放大，组织因子表达在同样发炎的内皮细胞表面。我们认为，这一假说的主要应用是流行的儿童溶血性尿毒症综合征(HUS)，在这种综合征中，产生食源性毒素的大肠杆菌会导致疾病状态，并伴有包括肾功能衰竭、癫痫发作、昏迷和死亡在内的并发症。我们的研究有望阐明针对阻断上述黏附分子和血管壁组织因子的HUS治疗的可能性。