Platelet granule formation and function in health and disease

血小板颗粒的形成及其在健康和疾病中的功能

• 批准号: 8846666
• 负责人: Michael S Marks
• 金额: $ 48.58万
• 依托单位: CHILDREN'S HOSP OF PHILADELPHIA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-05-07 至 2018-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8846666
• 关键词: Adhesions; Affect; Alpha Granule; Biogenesis; Blood Platelet Disorders; Blood Platelets; Blood Vessels; Bone Marrow; Calcium; Cell membrane; Cells; Chimeric Proteins; Coagulation Process; Complex; Cytoplasmic Granules; Data; Defect; Diagnostic; Disease; Disease susceptibility; Early Endosome; Endosomes; Epitopes; Fetal Liver; Genes; Health; Hemorrhage; Hemorrhagic Disorders; Hemostatic function; Hereditary Disease; Hermanski-Pudlak Syndrome; Human; Impairment; In Situ; Inflammation; Integral Membrane Protein; Label; Lysosomes; Megakaryocytes; Melanosomes; Membrane; Membrane Proteins; Modeling; Molecular; Morphology; Mus; Oculocutaneous Albinism; Organelles; Pathology; Pathway interactions; Patients; Phenotype; Pigments; Process; Proteins; Quinacrine; Role; Secondary to; Serotonin; Sorting - Cell Movement; Source; Staging; Structure; TFF1 gene; Testing; Therapeutic; Therapeutic Intervention; Thrombus; Tissues; Transport Process; Variant; Vesicle; Vesicle Transport Pathway; Wound Healing; angiogenesis; base; cell type; cohort; improved; in vivo; induced pluripotent stem cell; insight; melanocyte; mouse model; protein complex; reconstitution; small molecule; tool

DESCRIPTION (provided by applicant): Platelets fulfill essential functions in hemostasis, inflammation, angiogenesis, and other processes. Many of these functions require regulated secretion from three types of storage compartments - ¿ granules, dense granules, and lysosomes. Many hemorrhagic and thrombotic disorders are caused by dysregulation of granule formation and/or content release. In particular, bleeding diathesis in Hermansky-Pudlak syndrome (HPS) results from an absence of detectable platelet dense granules and consequent defects in activation-dependent release of calcium and ADP, which normally promote thrombus formation. Despite the importance of platelet granules, the mechanisms underlying their formation and membrane dynamics within megakaryocytes (MKs) and/or their derived platelets are largely uncharacterized, and the pathways regulated by the genes that are defective in the nine characterized HPS variants are not known. In other cell types, HPS-associated genes regulate vesicular transport processes required to deliver resident integral membrane proteins from early endosomes to lysosome-related organelles - cell type-specific intracellular storage compartments like ¿ and dense granules. We and our collaborators have recently identified two integral membrane proteins - SLC35D3 and VMAT2 - as candidate dense granule-specific cargoes that can serve as markers to study dense granule biogenesis. Surprisingly, these two cargoes localize to early endosomes in MKs from both wild-type and HPS model mice. Nevertheless, SLC35D3 is destabilized in platelets from the same HPS models. Based on these and other data, we hypothesize that dense granule integral membrane proteins are delivered from early endosomes to immature dense granules at a late stage of differentiation of platelets from MKs. We further hypothesize that dense granule membranes are not static but are constantly remodeled in active platelets, perhaps providing an avenue for delivery of pharmacological agents to platelet dense granules. Finally, preliminary data suggest that activation-induced content release is impaired not only from dense granules but also from ¿ granules and lysosomes in HPS model platelets, both in vivo and ex vivo. Since content release requires fusion of the granule membrane with the plasma membrane, we hypothesize that this secretory defect in HPS models reflects impaired cargo delivery of the fusion machinery to ¿ granules and lysosomes. We will test these hypotheses in the following Specific Aims: 1. To assess whether HPS-associated proteins regulate the dynamic localization of candidate dense granule membrane proteins in platelets. 2. To assess whether HPS impacts maturation of dense granules by fusion of distinct precursor organelles. 3. To test whether and how HPS subtypes impact ¿-granule and lysosome secretion from platelets.

描述（由申请方提供）：血小板在止血、炎症、血管生成和其他过程中发挥重要作用。这些功能中的许多需要来自三种类型的储存隔室的调节分泌-颗粒，致密颗粒和溶酶体。许多出血性和血栓性疾病是由颗粒形成和/或内容物释放的失调引起的。特别是，Hermansky-Pudlak综合征（HPS）的出血素质是由于缺乏可检测到的血小板致密颗粒以及随后的钙和ADP激活依赖性释放缺陷导致的，而钙和ADP的激活依赖性释放通常会促进血栓形成。尽管血小板颗粒的重要性，其形成的机制和膜动力学在巨核细胞（MK）和/或其衍生的血小板在很大程度上是未知的，和由基因调控的途径是有缺陷的九个特征HPS变体是未知的。在其他类型的细胞中，HPS相关基因调节囊泡运输过程，将早期内体中的固有膜蛋白运送到溶酶体相关的细胞器-细胞类型特异性的细胞内储存室，如颗粒和致密颗粒。我们和我们的合作者最近确定了两个完整的膜蛋白-SLC 35 D3和VMAT 2-作为候选的致密颗粒特异性货物，可以作为研究致密颗粒生物发生的标记。令人惊讶的是，这两种货物定位于来自野生型和HPS模型小鼠的MK中的早期内体。然而，SLC 35 D3在来自相同HPS模型的血小板中不稳定。基于这些和其他数据，我们假设致密颗粒膜整合蛋白在血小板从MK分化的晚期阶段从早期内体递送到未成熟的致密颗粒。我们进一步假设致密颗粒膜不是静态的，而是在活性血小板中不断重塑，这可能为将药理学试剂递送至血小板致密颗粒提供了途径。最后，初步的数据表明，激活诱导的内容物释放受损不仅从致密颗粒，但也从颗粒和溶酶体在HPS模型血小板，在体内和体外。由于内容物释放需要颗粒膜与质膜的融合，我们假设HPS模型中的这种分泌缺陷反映了融合机器向颗粒和溶酶体的货物递送受损。我们将在以下具体目标中检验这些假设：1。评估HPS相关蛋白是否调节血小板致密颗粒膜蛋白的动态定位。2.评估HPS是否通过不同前体细胞器的融合影响致密颗粒的成熟。3.检测HPS亚型是否以及如何影响血小板颗粒和溶酶体分泌。