Mechanisms of Notch1 in Aortic Valve Calcification

Notch1在主动脉瓣钙化中的作用机制

• 批准号: 7561331
• 负责人: VISHAL NIGAM
• 金额: $ 13.02万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-15 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7561331
• 关键词: Adult; Age; Aortic Valve Stenosis; Apoptosis; Bicuspid; Blood Vessels; Calcified; Calcium; Cardiac; Cardiovascular system; Cell Differentiation process; Cells; Computer Systems Development; Condition; Data; Deposition; Developed Countries; Developing Countries; Disease; Disruption; Event; Family; Family member; Gender; Gene Expression; Genes; Heart; Heart Diseases; Human; Hyperlipidemia; Hypertension; Immune system; In Vitro; Incidence; Infiltration; Inflammatory; Knockout Mice; Laboratories; Link; Lipids; Lipoproteins; Mediating; Mesenchymal; Mesenchyme; Molecular; Mus; Mutation; Myofibroblast; NOTCH1 gene; Osteoblasts; Osteogenesis; Pathologic; Pathway interactions; Pattern; Play; Pregnancy; Reporting; Repression; Risk Factors; Role; Signal Pathway; Signal Transduction; Smoking; Stenosis; Stress; Tissues; Work; abstracting; aortic valve; calcification; hemodynamics; macrophage; male; malformation; mouse model; notch protein; relating to nervous system; response; shear stress; vascular bed

DESCRIPTION (provided by applicant): Aortic valve calcification/stenosis is the third leading cause of adult heart disease and the most common form of acquired valvular disease in developed countries. The risk factors most closely linked to calcific aortic stenosis are the presence of a bicuspid aortic valve, increased age, male gender, smoking, hypertension, and elevated lipoproteins. Examination of human calcified aortic valve tissue has shown that several pathologic pathways are involved. However, the molecular mechanisms involved in valvular calcification have not been elucidated. Recently, the Srivastava lab reported two human families in which mutations in NOTCH1 were associated with early calcification of the aortic valve and bicuspid aortic valves. Notchl is a part of a highly conserved signaling pathway involved in many cellular events, including cell fate decisions and cell differentiation. This study demonstrated that Hrt2, a transcriptional represser that mediates the Notchl signal, could regulate the activity of Runx2, a central regulator of osteoblast cell fate determination in vitro. Our preliminary data show that Notchl heterozygous mice develop increased aortic valve calcification as compared to wild-type age matched littermates. I hypothesize that Notchl signaling represses pro-osteogenic pathways in aortic valve mesenchyme and that Notchl disruption may sensitize the valve to known risk factors that promote calcification. Specific Aim 1: To determine if disrupting Notchl signaling causes calcification of the aortic valve by activation of osteogenic pathways in mice. Notchl signaling will be conditionally disrupted in aortic valve tissue valves prenatally or postnatally. The aortic valves will be examined for functional stenosis, calcification, and expression of genes involved in bone formation. In addition, Notchl-deficient mice will be crossed with a mouse model of hyperlipidemia to examine the contribution of this risk factor to Notchl-mediated aortic valve calcification. Specific Aim 2: To elucidate the calcific pathways mediated by Notchl in mesenchymal and endocardial cells. Notchl expression will be disrupted or enhanced in cultured mesenchymal and endocardial cells under various conditions. Mesenchymal cells will be examined for activation or repression of osteoblast-specific gene expression and in some cases deposition of calcium. The interactions between Notchl signaling and three molecular pathways previously implicated in cardiovascular calcification, namely Runx2, Bmp2, and Wnt, will be examined. (End of Abstract)

描述（由申请人提供）： 主动脉瓣钙化/狭窄是成人心脏病的第三大原因，也是发达国家最常见的获得性瓣膜病。与钙化性主动脉瓣狭窄最密切相关的危险因素是二尖瓣主动脉瓣的存在、年龄增长、男性、吸烟、高血压和脂蛋白升高。对人类钙化主动脉瓣组织的检查表明，涉及多种病理途径。然而，瓣膜钙化的分子机制尚未阐明。最近，Srivastava 实验室报告了两个人类家族，其中 NOTCH1 突变与主动脉瓣和二尖瓣主动脉瓣的早期钙化有关。 Notch1是参与许多细胞事件（包括细胞命运决定和细胞分化）的高度保守信号通路的一部分。这项研究表明，介导Notch1信号的转录抑制因子Hrt2可以调节Runx2的活性，Runx2是体外成骨细胞命运决定的中央调节因子。我们的初步数据表明，与野生型年龄匹配的同窝小鼠相比，Notch1杂合小鼠的主动脉瓣钙化增加。我假设 Notch1 信号传导抑制主动脉瓣间质中的促骨生成途径，并且 Notch1 破坏可能会使瓣膜对促进钙化的已知危险因素敏感。具体目标 1：确定破坏 Notch1 信号传导是否会通过激活小鼠成骨途径导致主动脉瓣钙化。 Notch1信号传导将在产前或产后在主动脉瓣组织瓣膜中被条件性破坏。将检查主动脉瓣的功能性狭窄、钙化和骨形成相关基因的表达。此外，Notch1缺陷小鼠将与高脂血症小鼠模型杂交，以检查该危险因素对Notch1介导的主动脉瓣钙化的影响。具体目标 2：阐明间充质和心内膜细胞中 Notch1 介导的钙化途径。在各种条件下培养的间充质和心内膜细胞中Notch1表达将被破坏或增强。将检查间充质细胞的成骨细胞特异性基因表达的激活或抑制，以及在某些情况下的钙沉积。将检查Notch1信号传导与先前涉及心血管钙化的三个分子途径（即Runx2、Bmp2和Wnt）之间的相互作用。 （摘要完）