Aberrant Platelet Mechanisms in Inherited Human Platelet Function Disorders

遗传性人类血小板功能障碍中的异常血小板机制

• 批准号: 7904130
• 负责人: Angara Koneti Rao
• 金额: $ 38.03万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-08 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7904130
• 关键词: Address; Agonist; Antiplatelet Drugs; Bernard-Soulier Syndrome; Biochemical; Blood Platelet Disorders; Blood Platelets; Cardiovascular Diseases; Child; Complex; Core-Binding Factor; Cytoplasmic Granules; Defect; Disease; District of Columbia; Family member; Foundations; Functional disorder; GTP-Binding Proteins; Gene Expression; Gene Expression Profile; Gene Expression Profiling; Genes; Genetic; Genetic Medicine; Genomics; Hematology; Hematopoietic; Hemorrhage; Human; Human Genome Project; Individual; Inherited; Isoenzymes; Knowledge; Laboratories; Lead; Mediating; Medical center; Membrane Glycoproteins; Messenger RNA; Microarray Analysis; Molecular; Molecular Biology; Molecular Profiling; Mutation; Myosin ATPase; Myosin Light Chains; Pathway interactions; Patients; Pharmacotherapy; Phospholipase C; Phosphorylation; Physiological; Physiology; Platelet Activation; Platelet Storage Pool Deficiency; Protein Kinase C; Proteins; RUNX1 gene; Reporting; Research; Research Personnel; Selection Bias; Shotguns; Signal Transduction; Signal Transduction Pathway; System; Thrombasthenia; Thrombocytopenia; Thrombosis; Validation; base; clinical practice; experience; genome-wide; human disease; insight; mRNA Expression; novel; novel strategies; phospholipase C beta2; platelet protein P47; programs; protein activation; receptor; receptor function; response; synergism; tool; transcription factor

DESCRIPTION (provided by applicant): Despite tremendous advances in our understanding of platelet physiology, the underlying molecular mechanisms remain unknown in the vast majority of patients with inherited defects in platelet function. Mechanisms, such as deficiencies in membrane glycoproteins and the storage pool deficiency, are commonly considered but occur in a small proportion of patients. Most of these patients are characterized by a bleeding disorder, and impaired aggregation and dense granule secretion on platelet activation, and are currently lumped in a loosely defined group called "platelet secretion/activation defects." The molecular mechanisms in these patients are unknown. Several studies suggest that these patients may have abnormalities in the signal transduction mechanisms. We have documented specific defects in platelet phospholipase C-beta2, Gaq and protein kinase C-theta. Newer approaches are required to define the molecular defects in such patients who constitute an untapped reservoir of new information. We have now applied genome-wide platelet expression profiling using the Affymetrix microarrays to demonstrate a unique decrease in expression of myosin light chain 9 (MYL9, 70 fold decrease) and other genes in a patient with an inherited thrombocytopenia, impaired platelet responses (including myosin and pleckstrin phosphorylation and GPIIb-llla activation), and a heterozygous mutation in transcription factor CBFA2 (Core-binding factor A2), thereby providing proof of concept that expression profiling can indeed be applied to obtain new insights in patients with platelet dysfunction. The microarray technology has hitherto not been applied to such patients. In this project, we propose an integrated approach encompassing, a) detailed biochemical and functional studies on platelet mechanisms, b) platelet expression profiling and c) subsequent validation of the aberrant mechanisms using functional, mutational, biochemical and immunological approaches, to delineate the molecular mechanisms in 15 patients with inherited platelet dysfunction. We have extensive experience in all of the involved approaches. This project is a collaborative effort between two laboratories with strong complementary expertise. It represents application of the recent advances in genomics and the Human Genome Project to a group of patients who are frequently encountered but extremely poorly characterized. Our studies will provide a wealth of information on platelet mechanisms and on potential new targets for antithrombotic therapy.

描述（由申请人提供）：尽管我们对血小板生理学的理解取得了巨大进步，但绝大多数患有血小板功能遗传缺陷的患者的潜在分子机制仍然未知。通常会考虑膜糖蛋白缺陷和储存池缺陷等机制，但只发生在一小部分患者中。这些患者中的大多数以出血性疾病为特征，血小板活化时聚集和致密颗粒分泌受损，目前被归为松散定义的一组，称为“血小板分泌/活化缺陷”。这些患者的分子机制尚不清楚。多项研究表明这些患者的信号转导机制可能存在异常。我们已经记录了血小板磷脂酶 C-beta2、Gaq 和蛋白激酶 C-theta 的特定缺陷。需要更新的方法来定义这些患者的分子缺陷，这些患者构成了未开发的新信息库。我们现在使用 Affymetrix 微阵列应用全基因组血小板表达谱分析，证明患有遗传性血小板减少症、血小板反应受损（包括肌球蛋白和普莱克斯特林磷酸化和 GPIIb-IIIa 激活）以及血小板杂合突变的患者中肌球蛋白轻链 9（MYL9，降低 70 倍）和其他基因表达的独特降低。 转录因子 CBFA2（核心结合因子 A2），从而提供了概念证明，即表达谱确实可以应用于获得血小板功能障碍患者的新见解。迄今为止，微阵列技术尚未应用于此类患者。在这个项目中，我们提出了一种综合方法，包括：a) 对血小板机制进行详细的生化和功能研究，b) 血小板表达谱分析，以及 c) 使用功能、突变、生化和免疫学方法对异常机制进行后续验证，以描绘 15 名遗传性血小板功能障碍患者的分子机制。我们在所有涉及的方法方面都拥有丰富的经验。该项目是两个具有强大互补专业知识的实验室之间的合作成果。它代表了基因组学和人类基因组计划的最新进展对一组经常遇到但特征极少的患者的应用。我们的研究将提供有关血小板机制和抗血栓治疗潜在新靶点的大量信息。