The Biogenesis of Platelet-Derived Extracellular Vesicles and their Impact on Megakaryocyte Maturation

血小板源性细胞外囊泡的生物发生及其对巨核细胞成熟的影响

• 批准号: 10613503
• 负责人: Kellie Rae Machlus
• 金额: $ 57.73万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-20 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10613503
• 关键词: Acute; Address; Agonist; Binding; Biogenesis; Biology; Blood Platelets; Bone Marrow; Bone Marrow Cells; Cardiovascular Diseases; Cell Communication; Cell membrane; Cells; Clinical; Collagen; Data; Dependence; Development; Disease; Environment; Family; Gene Expression; Generations; Goals; Hematopoietic; Hemorrhage; Human; In Vitro; Inflammation; Inflammatory; Knowledge; Life; Link; Mediating; Megakaryocytes; Megakaryocytopoieses; Membrane Fusion; Messenger RNA; MicroRNAs; Modeling; Monomeric GTP-Binding Proteins; Morbidity - disease rate; Mothers; Mus; Outcome Study; Pathogenicity; Pathologic; Pathway interactions; Patients; Plasma; Platelet Activation; Platelet Count measurement; Production; Property; Regulation; Research; Signal Transduction; Steroids; Systemic Lupus Erythematosus; Therapeutic Intervention; Thrombin; Thrombocytopenia; Thrombopoiesis; Thrombopoietin; Time; Transcript; Up-Regulation; blood product; experimental study; extracellular vesicles; in vivo; inhibitor; insight; member; microvesicles; mimetics; mortality; new therapeutic target; novel; prevent; response; rho; rho GTP-Binding Proteins; side effect; thrombocytosis; transcription factor; transcriptome; uptake

The Biogenesis of Platelet-Derived Extracellular Vesicles and their Impact on Megakaryocyte Maturation Abstract Thrombocytopenia is a major clinical problem encountered in multiple conditions, and severe thrombocytopenia (platelet counts <50 x 10^9/L) can lead to life threatening bleeding. Current treatment options have severe side effects, are in limited supply, involve blood products, and the platelet response typically takes up to 12 days. Therefore, there is an urgent need to identify new thrombopoietic agents that increase platelet counts for patients. In many inflammatory conditions platelet counts rise, resulting in thrombocytosis, but what initiates this platelet up-regulation is not well understood. Our lab uses inflammation as a model of exacerbated thrombopoiesis that results in differences in platelet quality and quantity in order to 1) gain a better understanding of the basic biology of megakaryocyte (MK) maturation their production of platelets, 2) identify thrombopoietin (TPO) independent pathways of MK maturation, and 3) determine ways to reduce platelet-related morbidity and mortality in inflammation. We have discovered a novel regulator of MK maturation during inflammation: platelet-derived extracellular vesicles (PEVs) in the bone marrow. Our preliminary data indicate that platelets package and shed MVs in an agonist-specific mechanism dependent on Rho GTPase signaling; the mechanism of Rho-mediated regulation of PEV formation and packaging will be explored in Aim 1. We also found that PEVs enter the bone marrow from the plasma, and bind to and are endocytosed by MKs both in vitro and in vivo. In Aim 2, we will examine how platelet-derived MVs interact with MKs. Specifically, we will determine the mechanisms by which they bind to and are internalized by MKs and how their cargo transferred. In inflammatory conditions such as SLE, ongoing platelet activation increases levels of circulating PEVs. These PEVs deliver disease-related changes from the plasma milieu directly to MKs in the bone marrow, reprogramming the MKs to make more pathogenic platelets. In Aim 3, we will identify the PEV factors that alter MK gene expression and platelet content in SLE. Successful completion of the proposed experiments will, for the first time, provide a detailed roadmap of how PEVs alter the hematopoietic environment in the setting of inflammatory disease. The insights gained may identify novel therapeutic targets that (i) alter PEV poduction independent of platelet activation (Aim 1), (ii) hijack the PEV/MK interaction to alter MK maturation (Aim 2), and (iii) inhibit pathologic MK reprogramming during SLE and other inflammatory diseases (Aim 3).

血小板衍生的细胞外囊泡的生物发生及其对 巨核细胞成熟 抽象的 血小板减少症是在多种疾病中遇到的主要临床问题，严重 血小板减少症（血小板计数<50 x 10^9/L）可能导致威胁生命的出血。当前治疗 选项具有严重的副作用，供应有限，涉及血液产品和血小板反应 通常最多需要12天。因此，迫切需要确定新的血小板毒剂 增加患者的血小板计数。在许多炎症条件下，血小板计数增加，导致 血小板病，但引发该血小板上调的原因尚不清楚。我们的实验室使用炎症 作为恶化的血栓形成模型，导致血小板质量和数量差异，以便 1）更好地了解巨核细胞（MK）成熟的基本生物学 血小板，2）确定MK成熟的独立途径（TPO），3）确定方法 减少与血小板相关的发病率和炎症死亡率。我们发现了MK的新型调节器 炎症期间的成熟：骨髓中血小板衍生的细胞外囊泡（PEV）。我们的 初步数据表明，血小板包装和脱落MV在特定于激动剂的机制中 Rho GTPase信号传导； Rho介导的PEV形成和包装调节的机制将是 在AIM 1中探索。我们还发现PEVS从血浆中进入骨髓，并结合到并且是 由MKS在体外和体内均受到内吞。在AIM 2中，我们将研究血小板衍生的MV与 MKS。具体而言，我们将确定它们与MK和MKS内部结合的机制以及 他们的货物如何转移。在SLE等炎症条件下，持续的血小板激活增加 循环的PEV水平。这些PEV将与血浆环境的变化直接传递给MK 在骨髓中，对MK进行重新编程以制造更多的致病血小板。在AIM 3中，我们将确定 在SLE中改变MK基因表达和血小板含量的PEV因子。成功完成拟议的 实验将首次提供有关PEV如何改变造血的详细路线图 炎症性疾病的环境。获得的见解可以识别出新的治疗靶标 （i）更改PEV构元独立于血小板激活（AIM 1），（ii）劫持PEV/MK相互作用以改变 MK成熟（AIM 2）和（iii）在SLE和其他炎症过程中抑制病理MK重编程 疾病（目标3）。