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: 8703361
• 负责人: Michael S Marks
• 金额: $ 50.4万
• 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/8703361
• 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; Wound Healing; angiogenesis; base; cell type; cohort; improved; in vivo; induced pluripotent stem cell; insight; melanocyte; mouse model; protein complex; public health relevance; 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（由适用提供）：血小板履行止血，注射，血管生成和其他过程中的基本功能。这些功能中的许多功能都需要从三种类型的存储室进行调节 - »许多出血和血栓性疾病是由于颗粒形成和/或含量释放的失调引起的。特别是，由于缺乏可检测到的血小板致密颗粒以及随之而来的缺陷，钙和ADP的激活依赖性释放中，由于钙和ADP的激活依赖性释放，这通常促进血栓形成。尽管血小板颗粒的重要性，但其基础机制在巨核细胞（MKS）和/或它们的衍生血小板内的形成和膜动力学的基本机制在很大程度上是未表征的，并且尚不清楚由九个特征性HPS变体中有缺陷的基因调节的途径。在其他细胞类型中，与HPS相关的基因调节了将居民积分膜蛋白从早期内体传递到溶酶体相关细胞器所需的囊泡转运过程 - 细胞类型特异性的细胞内存储室（如»和致密颗粒）。我们和我们的合作者最近确定了两种积分膜蛋白-SLC35D3和VMAT2-是候选密集的颗粒特异性货物，可以用作研究致密颗粒生物发生的标志物。令人惊讶的是，这两种货物将野生型和HPS模型小鼠的MK中的早期内体局部定位于早期内体。然而，SLC35D3在同一HPS型号的血小板中不稳定。基于这些数据和其他数据，我们假设密集的颗粒整体膜蛋白是在血小板与MKS分化的后期从早期内体传递到未成熟的致密颗粒。我们进一步假设，致密的颗粒膜不是静态的，而是在活跃的血小板中不断重塑，也许是提供药物剂到血小板致密颗粒的途径。最后，初步数据表明，激活诱导的含量释放不仅受到密集颗粒的损害，而且受到HPS模型血小板中的颗粒和溶酶体的损害，无论是体内和Ex Vivo。由于内容释放需要将颗粒膜与质膜融合，因此我们假设HPS模型中的这种秘密缺陷反映了融合机器向颗粒和溶酶体的货物递送受损。我们将在以下特定目的中检验这些假设：1。评估与HPS相关的蛋白是否调节候选致密颗粒膜蛋白在血小板中的动态定位。 2。评估HP是否通过融合不同的前体细胞器来影响密集颗粒的成熟。 3。测试HPS子类型是否以及如何影响血小板的晶粒和溶酶体分泌。