The Role of Sox9 in Calcific Aortic Valve Disease

Sox9 在钙化性主动脉瓣疾病中的作用

• 批准号: 9229579
• 负责人: Joy Lincoln
• 金额: $ 37.38万
• 依托单位: RESEARCH INST NATIONWIDE CHILDREN'S HOSP
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-01 至 2019-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9229579
• 关键词: Address; Affect; Attenuated; Biological Assay; Bone Development; Calcified; Cell Differentiation process; Cell Nucleus; Cells; Cessation of life; Clinical; Data; Deposition; Development; Disease; Endothelial Cells; Exclusion; Functional disorder; Gene Expression; Genes; Genetic; Genetic Transcription; Genomics; Health; Heart Valve Diseases; Human; In Vitro; Lead; Left; Mediating; Messenger RNA; Modeling; Molecular; Movement; Mus; Nuclear; Nuclear Export; Operative Surgical Procedures; Osteoblasts; Pathogenesis; Pathologic; Pathway interactions; Patient-Focused Outcomes; Patients; Pharmacological Treatment; Pharmacology; Phosphorylation; Phosphotransferases; Play; Process; Proteins; Public Health; Publishing; Repression; Research; Role; Signal Transduction; Signaling Molecule; Stenosis; Stimulus; System; Testing; Therapeutic; Time; Transforming Growth Factor beta; United States; Work; aging population; aortic valve disorder; base; calcification; human disease; human tissue; improved; in vivo; inhibitor/antagonist; innovation; insight; interstitial cell; mouse model; new therapeutic target; osteogenic; pre-clinical; prevent; programs; public health relevance; response; success; transcription factor; transcriptome; transcriptome sequencing

 DESCRIPTION (provided by applicant): Heart valve disease results in over 23,000 annual deaths in the United States, with calcific aortic valve disease (CAVD) being the most prevalent. There is no pharmacological treatment to prevent or reverse CAVD, due to the poor understanding of underlying causes and therefore surgical intervention remains the only effective option. Valve calcification is mediated by valve interstitial cells (VICs) which in response to pathological stimuli abnormally express bone development genes and differentiate into osteoblast-like cells termed osteoVICs. These cells then deposit a calcified matrix that limit cusp movement and leads to stenosis. Despite this, the mechanisms that promote differentiation of osteoVICs are unknown, but our data suggests that Sox9 plays a role. Our data shows that in non-diseased valves Sox9 is highly expressed in the nuclei of VICs where it prevents calcification by functioning as a transcription factor to repress osteogenic gene expression while activating chondrogenic mRNAs that make up healthy valve leaflets. In contrast, we observe reduced Sox9 nuclear localization in several models of calcification including excised valves from human patients and mouse models of CAVD, and in vitro calcification assays, suggesting that Sox9 nuclear export is a common feature of CAVD. Furthermore, our published in vivo work shows that reduced Sox9 function in mice promotes differentiation of osteoVICs and CAVD while attenuating the contribution of chondrogenic matrix proteins indicating a causative role for reduced Sox9 function in CAVD. While our published and preliminary data have identified Sox9 as a key regulator of CAVD, the mechanism underlying its nuclear localization in health and disease are not known, yet identifying this will provide insights for the development of mechanistic-based therapies beyond surgical intervention. In this proposal we demonstrate that in healthy valves, Tgfß1 secreted from valve endothelial cells (VECs) molecularly communicates with Sox9 in VICs to retain nuclear localization and prevent calcification via RhoA kinase (ROCK) signaling. Therefore, we hypothesize that: In calcific aortic valve disease, abrogated expression of Tgfß1 signaling molecules in VECs prevents ROCK-mediated phosphorylation and nuclear localization of Sox9 in VICs, leading to differentiation of osteoVICs and CAVD. To do this, we will use innovative in vitro, in vitro, genomic and clinical approaches to address the following three specific aims: 1) Determine the mechanism by which Tgfß1 mediates Sox9 nuclear localization in healthy and osteogenic valve interstitial cells; 2) VECs isolated from mouse models of CAVD commonly demonstrate altered expression of Tgfß signaling molecules associated with dysfunction; and 3) Determine if pharmacological and genetic targeting to prevent Sox9 nuclear export prevents CAVD in vivo. Findings from this proposal will for the first time define a molecular pathway that underlies CAVD and identify mechanistic- based therapies that can be developed to treat affected human patients.

 描述（由申请人提供）：在美国，心脏瓣膜疾病每年导致超过23，000例死亡，其中钙化性主动脉瓣疾病（CAVD）最常见。由于对根本原因的认识不足，没有预防或逆转CAVD的药物治疗，因此手术干预仍然是唯一有效的选择。瓣膜钙化由瓣膜间质细胞（VIC）介导，所述VIC响应于病理刺激而异常表达骨发育基因并分化成成骨样细胞（称为osteoVIC）。然后这些细胞沉积存款钙化基质，限制尖瓣运动并导致狭窄。尽管如此，促进骨VIC分化的机制尚不清楚，但我们的数据表明Sox 9发挥了作用。我们的数据显示，在非病变瓣膜中，Sox 9在VIC的细胞核中高度表达，在VIC中，它通过作为转录因子抑制成骨基因表达，同时激活构成健康瓣膜小叶的软骨形成mRNA来防止钙化。相反，我们在几种钙化模型中观察到Sox 9核定位减少，包括来自人类患者和CAVD小鼠模型的切除瓣膜，以及体外钙化测定，表明Sox 9核输出是CAVD的共同特征。此外，我们发表的体内研究表明，小鼠中Sox 9功能降低促进了骨VIC和CAVD的分化，同时减弱了软骨形成基质蛋白的贡献，表明Sox 9功能降低在CAVD中的致病作用。虽然我们发表的和初步的数据已经确定Sox 9是CAVD的关键调节因子，但其在健康和疾病中的核定位机制尚不清楚，但确定这一点将为开发手术干预以外的机械疗法提供见解。在该提案中，我们证明了在健康瓣膜中，从瓣膜内皮细胞（VEC）分泌的Tgf β 1与VIC中的Sox 9分子通讯，以保持核定位并通过RhoA激酶（ROCK）信号传导防止钙化。因此，我们假设：在钙化性主动脉瓣疾病中，血管内皮细胞中Tgf β 1信号分子的表达被取消，阻止了ROCK介导的磷酸化和血管内皮细胞中Sox 9的核定位，导致了骨血管内皮细胞和CAVD的分化。为了做到这一点，我们将使用创新的体外、体外、基因组和临床方法来解决以下三个具体目标：1）确定Tgf β 1介导Sox 9在健康和成骨瓣膜间质细胞中的核定位的机制; 2）从CAVD小鼠模型分离的VEC通常表现出与功能障碍相关的Tgf β 1信号分子的表达改变;和3）确定防止Sox 9核输出的药理学和遗传靶向是否在体内防止CAVD。这项提案的发现将首次定义CAVD基础的分子途径，并确定可开发用于治疗受影响人类患者的基于机制的疗法。