Cytoskeletal Mechanisms of Platelet Formation

血小板形成的细胞骨架机制

• 批准号: 8979711
• 负责人: JOSEPH E ITALIANO
• 金额: $ 43.76万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8979711
• 关键词: Actins; Biogenesis; Biological; Blood Platelets; Blood Vessels; Burn injury; Cells; Coagulation Process; Complement; Cytoplasmic Granules; Cytoskeletal Proteins; Cytoskeleton; Development; Event; Fluorescence; Foundations; Functional disorder; Funding; Generations; Goals; Hemostatic function; Hereditary Disease; In Vitro; Infusion procedures; Injury; Investigation; Knowledge; Laboratories; Lead; Life; Location; Maintenance; Mechanics; Megakaryocytes; Membrane; Methodology; Microscopy; Microtubule-Associated Proteins; Microtubules; Modeling; Molecular; Morphology; Motor; Movement; Operative Surgical Procedures; Organ Transplantation; Organelles; Pathway interactions; Patients; Platelet Count measurement; Play; Process; Production; Proteins; Radiation therapy; Research Support; Resolution; Role; Shapes; Slide; Spectrin; Staging; Structure; System; Testing; Thrombocytopenia; Thrombosis; Trauma; Work; base; chemotherapy; filamin; improved; in vitro Model; insight; membrane skeleton; novel; novel therapeutic intervention; particle; reconstitution; repaired; research study; skeletal

DESCRIPTION (provided by applicant): Blood platelets play an essential role in hemostasis, as well as in the pathophysiology of thrombosis. The purpose of this proposal is to investigate the cytoskeletal mechanics of platelet formation. Although it is well established that platelets originate from megakaryocytes, many unanswered questions remain regarding the mechanics by which platelets are formed and released. The favored model of platelet formation recognizes that terminally differentiated megakaryocytes extend long cytoplasmic processes, designated proplatelets, which function as essential intermediate structures in platelet biogenesis. We have recently discovered a new intermediate stage in platelet production, the preplatelet, and have established that microtubules and the spectrin-based membrane skeleton are involved in platelet production. How preplatelets convert into platelets, however, is not known, and many of the molecular details underlying the contribution of the cytoskeleton to platelet production remain to be uncovered. The three Specific Aims of this proposal focus on the role of the cytoskeleton in platelet production. Specific Aim 1 will examine how microtubules convert preplatelets into barbell shapes that divide to release platelets, with the goal of testing the hypothesis that microtubule sliding powers preplatelet fission and release. The role of specific microtubule-associated proteins will be established. Specific Aim 2 will define how the spectrin-based membrane skeleton contributes to proplatelet production. Using a newly developed permeabilized proplatelet system, the spatial and temporal localization, as well as the function of key membrane skeleton proteins will be established. The role of the Filamin-GPIba-actin linkage in the preplatelet to platelet transition will be tested. Finally, Specific Aim 3 will evaluate the importance of microtubules in forming the demarcation membrane system, with the goal of using an in vitro model to determine if the demarcation membrane system forms by membrane- associated motors moving over microtubules or by the attachment to the tips of elongating microtubules. These experiments will define the function of specific cytoskeletal proteins in demarcation membrane system formation. Taken together, we expect that findings made as a result of this investigation will provide an improved understanding of the molecular mechanisms that regulate platelet formation, and lay the foundation for novel therapeutic approaches to accelerate platelet production in patients with thrombocytopenia, as well as strategies aimed at improving the in vitro generation of platelets for infusion.

描述（由申请人提供）：血小板在止血以及血栓形成的病理生理学中发挥重要作用。该提案的目的是研究血小板形成的细胞骨架力学。尽管血小板起源于巨核细胞这一点已得到充分证实，但关于血小板形成和释放的机制仍有许多未解答的问题。受欢迎的血小板形成模型认识到终末分化的巨核细胞延伸长的细胞质过程，称为前血小板，其在血小板生物发生中充当重要的中间结构。我们最近发现了血小板产生的一个新的中间阶段，即前血小板，并确定微管和基于血影蛋白的膜骨架参与血小板的产生。然而，前血小板如何转化为血小板尚不清楚，并且细胞骨架对血小板产生的贡献的许多分子细节仍有待揭示。该提案的三个具体目标重点关注细胞骨架在血小板生成中的作用。具体目标 1 将研究微管如何将前血小板转化为杠铃形状并分裂以释放血小板，目的是检验微管滑动为前血小板裂变和释放提供动力的假设。特定微管相关蛋白的作用将被确定。具体目标 2 将定义基于血影蛋白的膜骨架如何促进前血小板的产生。使用新开发的透化前血小板系统，将建立关键膜骨架蛋白的空间和时间定位以及功能。将测试细丝蛋白-GPIba-肌动蛋白连接在前血小板向血小板转变中的作用。最后，具体目标 3 将评估微管在形成分界膜系统中的重要性，目的是使用体外模型来确定分界膜系统是通过在微管上移动的膜相关马达还是通过附着在尖端上形成的的微管伸长。这些实验将定义特定细胞骨架蛋白在分界膜系统形成中的功能。总而言之，我们期望这项研究的结果将有助于更好地理解调节血小板形成的分子机制，并为加速血小板减少症患者血小板生成的新治疗方法以及旨在治疗血小板减少症的策略奠定基础。改善输注用血小板的体外生成。