Proteoglycan Regulation During Cardiac Valve Development and Homeostasis

心脏瓣膜发育和稳态过程中的蛋白多糖调节

• 批准号: 8760823
• 负责人: Christine Bruins Kern
• 金额: $ 37.38万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8760823
• 关键词: ADAMTS; Address; Adult; Affect; Alleles; American; Architecture; Area; Bicuspid; Biological Availability; Cell Culture Techniques; Cell Differentiation process; Cell Lineage; Cells; Cleaved cell; Clinical Trials; Collagen; Confocal Microscopy; Data; Defect; Degenerative polyarthritis; Development; Diagnostic; Disease; Equilibrium; Etiology; Exhibits; Extracellular Matrix; Functional disorder; Future; Gene Mutation; Genes; Goals; Heart Valve Diseases; Heart Valves; Histopathology; Homeostasis; Investigation; Laboratories; Lead; Ligands; Lung; Maintenance; Mediating; Mesenchymal; Metalloproteases; Mitral Valve; Modeling; Morphology; Mus; Myocardial; Nodule; Operative Surgical Procedures; Penetrance; Peptide Hydrolases; Peptides; Pharmacologic Substance; Pharmacological Treatment; Phenotype; Phosphorylation; Plant Roots; Play; Population; Predisposing Factor; Pregnancy; Proteoglycan; Publishing; Pulmonary valve structure; Regulation; Research; Research Personnel; Risk Factors; Role; Sclerosis; Signal Transduction; Smooth Muscle Actin Staining Method; Stratification; Tamoxifen; Testing; Therapeutic; Time; Tissues; Transforming Growth Factor beta; aged; aortic valve; aortic valve disorder; base; bicuspid aortic valve; cell behavior; clinically relevant; cost; feeding; filamin; in vivo; inhibitor/antagonist; malformation; mouse model; novel; periostin; postnatal; public health relevance; research study; response; semilunar valve; spatiotemporal; valvular insufficiency; versican

DESCRIPTION (provided by applicant): Adult cardiac valve disease affects up to 5% of Americans with approximately 25% of the aged population developing aortic valve sclerosis, a marker of valve disease. The primary treatment of valvular insufficiency is surgical intervention with an estimated cost of $1 billion per year in the US. The fact that most diseased valves have an underlying malformation suggests that determining the etiology of valve diseases lies in the discovery of novel mechanisms and genes that are involved in valve development. However, progress in discovering the roots of valve disease has been limited in part due to the lack of viable mouse models that exhibit significant penetrance of a cardiac valve phenotype. A hallmark of both developmental myxomatous valve abnormalities and adult disease is the loss of stratification of extracellular matrix (ECM) and the accumulation of the ECM proteoglycans including versican. The ADAMTS (ADisintegrin-like And Metalloprotease domain with ThromboSpondin-type 1 motifs) proteoglycanases are a specific class of extracellular matrix metalloproteases that cleave proteoglycans. Mice deficient in ADAMTS5 develop severely enlarged cardiac valves by late gestation with significant accumulation of versican, the ECM substrate of ADAMTS5. In vivo reduction of versican, rescues the Adamts5-/- valve phenotype, and demonstrates that cleavage of versican is required for its clearance from the provisional ECM. To date, versican is the only ECM substrate of ADAMTS5 known to accumulate in ADAMTS5 deficient valves. Prevalvular mesenchymal cells from the Adamts5-/- mice maintain Sox9 expression and show elevated levels of proliferation suggesting they do not differentiate like their WT counterparts. Our published data also show that ECM accumulation of versican inhibits Smad2 phosphorylation. Intergenetic cross of the Adamts5-/- with Smad2-/- exacerbates the valve phenotype and results in a high penetrance (80%) of bicuspid aortic and pulmonary valves. In this application we seek to elucidate ECM-cell signaling mechanisms that are activated in response to proteoglycan cleavage and integral to the valve maturation and homeostasis. Since ADAMTS5 peptide inhibitors are in clinical trials to alleviate osteoarthritis, investigation into the requirement of proteoglycan cleavage in normal valve development and homeostasis has immediate clinical relevance. The three specific aims of our application test our overarching hypothesis that ADAMTS5 mediated versican cleavage plays a pivotal role in semilunar cardiac valve maturation through interconnections with TGFbeta signaling that control cell differentiation and the balance of proteoglycan-rich and fibrous ECM. Aim 1: Determine the mechanism by which ADAMTS5 dependent ECM remodeling upregulates Smad2 phosphorylation during semilunar valve development. Aim 2: Determine the spatiotemporal expression of ADAMTS5 that is required to remodel the provisional ECM of endocardial cushions during semilunar valve development. Aim 3: Determine the consequence of ADAMTS5 deficiency on adult murine valve ECM and function.

描述（由申请人提供）：成人心脏瓣膜疾病影响高达5%的美国人，其中约25%的老年人群发生主动脉瓣硬化，这是瓣膜疾病的标志物。瓣膜功能不全的主要治疗方法是手术干预，在美国每年的估计费用为10亿美元。事实上，大多数患病的瓣膜具有潜在的畸形，这表明确定瓣膜疾病的病因在于发现参与瓣膜发育的新机制和基因。然而，在发现瓣膜疾病的根源方面的进展受到限制，部分原因是缺乏表现出心脏瓣膜表型显著突变的可行小鼠模型。发育性粘液瘤性瓣膜异常和成人疾病的标志是细胞外基质（ECM）分层的丧失和ECM蛋白聚糖（包括多功能蛋白聚糖）的积累。ADAMTS（具有血栓蛋白1型基序的去整合素样金属蛋白酶结构域）蛋白聚糖酶是一类特异性的细胞外基质金属蛋白酶，其切割蛋白聚糖。缺乏ADAMTS 5的小鼠在妊娠晚期出现严重的心脏瓣膜扩大，并伴有多功能蛋白聚糖（ADAMTS 5的ECM底物）的显著积累。多功能蛋白聚糖的体内减少挽救了Adamts 5-/-瓣膜表型，并证明多功能蛋白聚糖的切割是其从临时ECM中清除所需的。迄今为止，多功能蛋白聚糖是已知在ADAMTS 5缺陷瓣膜中积累的ADAMTS 5的唯一ECM底物。来自Adamts 5-/-小鼠的瓣膜前间充质细胞保持Sox 9表达，并显示出升高的增殖水平，表明它们不像WT对应物那样分化。我们发表的数据还表明多功能蛋白聚糖的ECM积累抑制Smad 2磷酸化。Adamts 5-/-与Smad 2-/-的遗传间杂交加剧了瓣膜表型，并导致二叶主动脉瓣和肺动脉瓣的高瓣膜率（80%）。在本申请中，我们试图阐明ECM细胞信号传导机制，其响应于蛋白聚糖切割而被激活，并且是瓣膜成熟和稳态的组成部分。由于ADAMTS 5肽抑制剂正在进行缓解骨关节炎的临床试验，因此研究正常瓣膜发育和体内平衡中蛋白聚糖切割的需求具有直接的临床意义。我们申请的三个具体目的测试了我们的总体假设，即ADAMTS 5介导的多功能蛋白聚糖切割通过与控制细胞分化和富含蛋白聚糖和纤维ECM的平衡的TGF β信号传导的相互联系在半月心瓣膜成熟中起关键作用。目的1：确定半月瓣发育过程中ADAMTS 5依赖性ECM重塑上调Smad 2磷酸化的机制。目标二：确定在半月瓣发育过程中重塑内膜垫临时ECM所需的ADAMTS 5的时空表达。目的3：探讨ADAMTS 5基因缺陷对成年小鼠瓣膜细胞外基质及功能的影响。