Chromatin Regulation of Heart Valve Development

心脏瓣膜发育的染色质调控

基本信息

批准号：
9386666
负责人：
KRYN STANKUNAS
金额：
$ 33.3万
依托单位：
UNIVERSITY OF OREGON
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-12-15 至 2020-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9386666
关键词：
Adult Alleles Bicuspid Binding Biochemical Biological Markers Cell Culture Techniques Cells Chromatin Chromatin Remodeling Factor Complex Congenital Abnormality Defect Development Developmental Process Diagnostic Disease Disease Progression Embryo Epigenetic Process Event Future Gene Expression Regulation Gene Targeting Genetic Genetic Models Genetic Transcription Genome Goals Growth Heart Heart Valves Human Genetics Light LoxP-flanked allele Mesenchymal Mesenchyme Modeling Molecular Morphogenesis Mus Outcome Outcomes Research Pathway interactions Pattern Phenotype Population Process Regenerative Medicine Regulation Regulator Genes Research Role Signal Pathway Signal Transduction Technology Testing Tissues Transcript Transcriptional Regulation Tube WNT Signaling Pathway aortic valve disorder base bicuspid aortic valve chromatin remodeling design empowered human disease improved interstitial loss of function mouse model neglect novel novel diagnostics novel therapeutics preclinical trial prevent programs public health relevance repaired semilunar valve therapeutic target transcription factor transcriptome transcriptome sequencing

项目摘要

DESCRIPTION (provided by applicant): Semilunar valve (SLV) diseases, including bicuspid aortic valves (BAV), are remarkably common and yet their genetic and developmental origins are poorly understood. Likewise, it remains unclear how disrupted embryonic valve development progresses into overt valve disease. Our long-term goal is to understand how gene regulation drives sequential developmental processes that ultimately produce complex, patterned valves and how these processes go awry in SLV disease. These gene regulatory events require transcription factors to interface with a chromatinized genome, suggesting that chromatin regulators are key components of SLV developmental networks. One important event is an endocardial-to-mesenchymal transformation (EMT) that occurs early in valve development to populate endocardial cushions (ECs), including the proximal outflow tract (pOFT) cushions that contribute tissue to SLVs. Our objectives are to 1) understand how chromatin remodeling integrates with cell signaling during EMT, and 2) determine mechanisms by which disruptions of valve development progress into diseased SLVs. Our central hypothesis is that endocardial Brg1-associated factor (BAF) chromatin remodeling complexes interact with Wnt signaling effectors to promote pOFT EMT. As a result, when endocardial Brg1 is deleted a subtype of OFT mesenchyme is depleted. Without these cells, cusp overgrowth and fusion results in thickened and malpatterned SLVs, including BAV. The rationale for our efforts is that defining chromatin remodeling roles during EMT will shed light on how SLV disease originates. Further, our mouse models of SLV disease will enable an understanding of the cellular and molecular progression of valve disease. Our specific aims are: 1) Determine the molecular networks that the BAF complex interfaces with to direct EMT and 2) Determine mechanisms of SLV disease progression in mice lacking endocardial- lineage Brg1. In pursuit of the first Aim, we will compare cellular and molecular pOFT defects seen in unpublished genetic models disrupting Brg1 and Wnt signaling. We will apply a transformative new TU-tagging technology to define dynamic, endocardial transcriptomes dependent on each pathway. Using new cell culture approaches, we will test biochemical interactions between BAF, Wnt effectors, and chromatin in EC cells. For the second Aim, we will use genetic lineage tracing to determine contributions of EMT-derived cells to distinct SLV regions, define interactions between SLV mesenchyme sub-populations, characterize misexpressed transcripts that may drive SLV disease progression, and describe a new mouse model of adult SLV disease of potential utility in preclinical trials. Our proposed research uses novel technological and paradigmatic approaches to pursue unresolved questions of SLV development and disease. These contributions will be significant as they will shed light on the human genetics of SLV disease and inform regenerative medicine approaches. Our newly identified transcripts associated with a BAV model may represent biomarkers for disease diagnostics or therapeutic targets to prevent congenitally abnormal valves from becoming diseased.

描述（由申请人提供）：半月瓣（SLV）疾病，包括二叶式主动脉瓣（BAV），非常常见，但对其遗传和发育起源知之甚少。同样，目前尚不清楚胚胎瓣膜发育中断如何发展为明显的瓣膜疾病。我们的长期目标是了解基因调控如何驱动顺序发育过程，最终产生复杂的、有图案的瓣膜，以及这些过程如何在 SLV 疾病中出错。这些基因调控事件需要转录因子与染色质基因组相互作用，这表明染色质调控因子是 SLV 发育网络的关键组成部分。一个重要的事件是心内膜向间质转化 (EMT)，它发生在瓣膜发育早期，以填充心内膜垫 (EC)，包括为 SLV 提供组织的近端流出道 (pOFT) 垫。我们的目标是 1) 了解 EMT 过程中染色质重塑如何与细胞信号传导整合，2) 确定瓣膜发育破坏进展为患病 SLV 的机制。我们的中心假设是心内膜 Brg1 相关因子 (BAF) 染色质重塑复合物与 Wnt 信号传导效应子相互作用，促进 pOFT EMT。因此，当心内膜 Brg1 被删除时，OFT 间充质的亚型就会耗尽。如果没有这些细胞，尖点过度生长和融合会导致 SLV 增厚和畸形，包括 BAV。我们努力的理由是，定义 EMT 期间染色质重塑的作用将有助于揭示 SLV 疾病的起源。此外，我们的 SLV 疾病小鼠模型将有助于了解瓣膜疾病的细胞和分子进展。我们的具体目标是：1) 确定 BAF 复合物介导 EMT 的分子网络；2) 确定缺乏心内膜谱系 Brg1 的小鼠 SLV 疾病进展的机制。为了实现第一个目标，我们将比较未发表的破坏 Brg1 和 Wnt 信号传导的遗传模型中发现的细胞和分子 pOFT 缺陷。我们将应用一种革命性的新 TU 标记技术来定义依赖于每个通路的动态心内膜转录组。使用新的细胞培养方法，我们将测试 EC 细胞中 BAF、Wnt 效应子和染色质之间的生化相互作用。对于第二个目标，我们将使用遗传谱系追踪来确定 EMT 衍生细胞对不同 SLV 区域的贡献，定义 SLV 间充质亚群之间的相互作用，表征可能驱动 SLV 疾病进展的错误表达转录本，并描述一种新的小鼠模型成人 SLV 疾病在临床前试验中具有潜在用途。我们的拟议的研究使用新颖的技术和范例方法来解决 SLV 发展和疾病的未解决问题。这些贡献将意义重大，因为它们将揭示 SLV 疾病的人类遗传学并为再生医学方法提供信息。我们新发现的与 BAV 模型相关的转录本可能代表疾病诊断的生物标志物或预防先天性异常瓣膜患病的治疗靶点。