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: 10394422
• 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/10394422
• 关键词: Acute; Address; Agonist; Binding; Biogenesis; Biology; Blood Platelets; Bone Marrow; Bone Marrow Cells; Cardiovascular Diseases; Cell membrane; Cells; Clinical; Collagen; Data; Dependence; Development; Disease; Environment; Family; Gene Expression; Generations; Goals; Hematopoietic; Hemorrhage; Human; In Vitro; Inflammation; Inflammatory; Knowledge; Lead; 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).

血小板来源的胞外囊泡的生物发生及其对血管紧张素转换酶的影响 巨核细胞成熟 摘要 血小板减少症是在多种情况下遇到的主要临床问题，严重的 血小板减少症(血小板计数50×109/L)可导致危及生命的出血。目前的治疗方法 选择方案有严重的副作用，供应有限，涉及血液产品，以及血小板反应 通常需要12天。因此，迫切需要确定新的造血剂，以 增加患者的血小板计数。在许多炎症情况下，血小板计数上升，导致 血小板增多，但启动这种血小板上调的原因还不是很清楚。我们的实验室使用的是炎症 作为一种加剧的血小板生成模型，导致血小板质量和数量的不同，以便 1)更好地了解巨核细胞(MK)成熟及其产生的基本生物学 血小板，2)确定促血小板生成素(TPO)非依赖的MK成熟途径，3)确定 减少炎症中与血小板相关的发病率和死亡率。我们发现了一种新的MK调节因子 炎症过程中的成熟：骨髓中的血小板衍生细胞外小泡(PEV)。我们的 初步数据表明，血小板以激动剂特异的机制包装和释放MVS，依赖于 Rho GTPase信号转导；Rho介导的PEV形成和包装的调节机制将是 在目标1中探索。我们还发现PEV从血浆进入骨髓，与 体外和体内均可被巨噬细胞吞噬。在目标2中，我们将研究血小板衍生的MVS是如何与 MKS。具体地说，我们将确定它们与MK和MK结合并内化的机制 他们的货物是如何转运的。在炎症条件下，如系统性红斑狼疮，正在进行的血小板激活增加 循环中的PEV水平。这些PEV将与疾病相关的变化从血浆环境直接传递到MK 在骨髓中，对巨噬细胞重新编程，以制造更多致病的血小板。在目标3中，我们将确定 改变SLE患者MK基因表达和血小板含量的PEV因子。圆满完成拟议中的 实验将首次提供PEV如何改变造血的详细路线图 在炎症性疾病背景下的环境。获得的洞察力可能会确定新的治疗靶点 (I)改变PEV的产生而不依赖于血小板的激活(目标1)，(Ii)劫持PEV/MK相互作用以改变 MK成熟(目标2)，以及(Iii)在SLE和其他炎症性疾病期间抑制病理性MK重新编程 疾病(目标3)。