Proteoglycan Metabolism During Cardiac Valve Development and Disease

心脏瓣膜发育和疾病期间的蛋白多糖代谢

• 批准号: 10341254
• 负责人: Christine Bruins Kern
• 金额: $ 51.75万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2025-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10341254
• 关键词: Active Sites; Adult; Affect; Amino Acids; Aneurysm; Aorta; Aortic Rupture; Arteries; Behavior; Blood Vessels; Blood flow; Cardiac; Cardiovascular system; Cell Lineage; Cells; Coronary artery; Data; Defect; Degenerative polyarthritis; Development; Disease; Endothelium; Event; Exhibits; Extracellular Matrix; Fetus; Heart Valves; Human; Individual; Investigation; Label; Lasers; Lead; Light; Mesenchymal; Metabolism; Modeling; Molecular; Morphology; Mus; Mutation; Myocardial; Neural Crest; Organ; Patients; Pattern; Penetrance; Pharmaceutical Preparations; Pregnant Women; Prevalence; Proteoglycan; Publishing; Reporting; Reproducibility; Research; Risk Factors; Role; Rupture; Signal Transduction; Stromelysin 1; Sudden Death; Testing; Therapeutic; Tissues; aggrecan; aortic valve; aortic valve disorder; bicuspid aortic valve; cell behavior; comorbidity; congenital heart disorder; design; experimental study; in vivo; inhibitor; insight; malformation; mouse model; new therapeutic target; prevent; side effect; targeted sequencing; therapeutic target; therapeutically effective; transcriptome sequencing; versican

Summary: Approximately 1.5% of individuals have a Bicuspid Aortic Valve (BAV) that can result in insufficient blood flow and organ damage (1, 2). A BAV is also an independent risk factor for ascending aortic wall complications that can lead to rupture and sudden death. However, the cell and molecular basis for the BAV is unknown. Even basic aspects of BAV formation are undefined due to contributions from multiple cell lineages and a lack of highly penetrant viable BAV mouse models. Dysfunctional aortic valves exhibit massive accumulation of the extracellular matrix (ECM) proteoglycans versican (Vcan) and aggrecan (Acan) (3-7) but the origin and consequence of excess proteoglycans is largely unknown. Since proteoglycans are highly stable, abundance is regulated primarily by proteolytic degradation which led us to investigate a role for proteoglycan cleavage. We discovered that loss of a single ECM proteoglycanase, Adamts5, results in enlarged aortic valves with ascending aortopathies (100%). These defects co-localize with substantial increases in Vcan and Acan in the affected tissues (8-10) that mirror the human condition. Mechanistically, in Adamts5-/- aortic valve primordia with excess Vcan there is a reduction of pSmad2, and when Smad2 is reduced further by generating Adamts5-/- ;Smad2+/- mice, there is a high penetrance of BAV (75%), much higher than seen in other mouse BAV models. The objective of this proposal is to utilize the viable Adamts5-/-;Smad2+/- mice that exhibit a high percentage of BAV, to define morphological events, cell behaviors and factors that when disrupted contribute to BAV formation. Since excess Vcan is a hallmark of dysfunctional and diseased valves, use of a model with mutations that impact the control of Vcan content, may shed light on how proteoglycan metabolism is regulated in development and may also give insight into disease. Experiments test the hypothesis that ECM Vcan cleavage coordinates mesenchymal cell behaviors and myocardial cell contributions that are required for the tricuspid morphology of aortic valves. The hypothesis is tested in two aims: Aim 1 tests the impact of altered Vcan cleavage on mesenchymal cell lineage behaviors that are required for aortic valve formation. Our preliminary data show that loss of Vcan cleaved fragments and excess intact Vcan, disrupted lineage-specific patterning in the developing aortic valves of the BAV Adamts5-/-;Smad2+/-mice. A combination of ex vivo, and in vivo approaches will decipher the lineage-specific cell behaviors, and guidance factors that are dependent on Vcan cleavage and to prevent BAV. Although dogma states that valve cusps arise from mesenchymal cells, Aim 2 investigates the consequence of excess Vcan on the myocardial cell lineage contributions to the developing aortic valve in Adamts5-/-;Smad2+/- mice and other murine models of BAV. Our preliminary data show myocardial lineage expression of Adamts5 is required to clear Vcan-rich ECM and to form the non-coronary cusp of the aortic valve. Due to the emerging prevalence of excess Vcan in BAV, the investigation into ECM turnover will allow insight into the molecular and cellular origins of aortic valve diseases, which may lead to therapeutic advances.

摘要：大约 1.5% 的人有二叶式主动脉瓣 (BAV)，这可能会导致主动脉瓣不足 血流和器官损伤 (1, 2)。 BAV 也是升主动脉壁的独立危险因素 可能导致破裂和猝死的并发症。然而，BAV 的细胞和分子基础是 未知。由于多种细胞谱系的贡献，甚至 BAV 形成的基本方面也未定义 以及缺乏高渗透性的可行 BAV 小鼠模型。功能失调的主动脉瓣表现出巨大的 细胞外基质 (ECM) 蛋白聚糖多功能蛋白聚糖 (Vcan) 和聚集蛋白聚糖 (Acan) (3-7) 的积累，但 过量蛋白聚糖的起源和后果在很大程度上尚不清楚。由于蛋白多糖高度稳定， 丰度主要由蛋白水解降解调节，这促使我们研究蛋白聚糖的作用 分裂。我们发现单个 ECM 蛋白聚糖酶 Adamts5 的缺失会导致主动脉瓣扩大 患有升主动脉病（100%）。这些缺陷与 Vcan 和 Acan 的大幅增加共同定位 反映人类状况的受影响组织 (8-10)。从机制上讲，在 Adamts5-/- 主动脉瓣原基中 当 Vcan 过量时，pSmad2 会减少，当 Smad2 通过生成 Adamts5-/- 进一步减少时 ；Smad2+/- 小鼠，BAV 外显率很高（75%），远高于其他小鼠 BAV 模型。 该提案的目的是利用可存活的 Adamts5-/-;Smad2+/- 小鼠，该小鼠表现出高百分比 BAV，定义形态事件、细胞行为和被破坏时有助于 BAV 形成的因素。 由于 Vcan 过多是瓣膜功能失调和患病的标志，因此使用具有影响的突变的模型 Vcan 含量的控制，可能有助于阐明蛋白多糖代谢在发育和发育过程中是如何调节的。 还可以深入了解疾病。实验验证了 ECM Vcan 裂解坐标的假设 三尖瓣形态所需的间充质细胞行为和心肌细胞贡献 主动脉瓣。该假设通过两个目标进行检验： 目标 1 测试改变 Vcan 裂解对 主动脉瓣形成所需的间充质细胞谱系行为。我们的初步数据表明 Vcan 裂解片段和过量完整 Vcan 的丢失，破坏了发育中的谱系特异性模式 BAV Adamts5-/-;Smad2+/- 小鼠的主动脉瓣。离体和体内方法的结合将破译 谱系特异性细胞行为以及依赖于 Vcan 裂解并阻止其发生的指导因子 巴夫。尽管教条指出瓣膜尖瓣源自间充质细胞，但 Aim 2 研究了 过量 Vcan 对心肌细胞谱系对主动脉瓣发育的贡献的影响 Adamts5-/-；Smad2+/- 小鼠和其他 BAV 小鼠模型。我们的初步数据显示心肌谱系 Adamts5 的表达是清除富含 Vcan 的 ECM 和形成主动脉瓣非冠状尖瓣所必需的。 由于 BAV 中出现过量 Vcan 的现象，对 ECM 营业额的调查将有助于深入了解 研究主动脉瓣疾病的分子和细胞起源，这可能会带来治疗进展。