Integrative genomics to define osteocyte differentiation, regulation and function

综合基因组学定义骨细胞分化、调节和功能

• 批准号: 8691297
• 负责人: J WESLEY PIKE
• 金额: $ 34万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-08 至 2019-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8691297
• 关键词: Affect; Binding; Biological; Bone Diseases; Bone Matrix; Bone Surface; Bone remodeling; Cardiovascular Physiology; Cardiovascular system; Cell Culture System; Cells; Cellular Mechanotransduction; ChIP-seq; Chromatin; Communication; Cues; DNA; DNA Binding; Data; Data Set; Disease; Endocrine; Enhancers; Epigenetic Process; Femur; Gene Expression; Gene Expression Profile; Gene Targeting; Genes; Genomics; Histones; Homeostasis; Hormones; In Vitro; Individual; Kidney; Lead; Life; Location; Longevity; Maintenance; Marrow; Mediating; Medicine; Methods; Minerals; Modification; Molecular; Monitor; Morphology; Mus; Muscle; Nerve; Neurons; Osteoblasts; Osteocytes; Osteogenesis; Osteolysis; Osteoporosis; Pathologic; Pathway interactions; Pattern; Play; Process; Production; Property; RNA Sequences; Regulation; Relative (related person); Role; Route; Signal Pathway; Signal Transduction; Signal Transduction Pathway; Site; Skeleton; Therapeutic Intervention; Transact; Up-Regulation; Van Buchem disease; Work; base; bone; bone cell; cell type; epigenomics; genome-wide; in vivo; in vivo Model; inorganic phosphate; insight; mineralization; novel; paracrine; prevent; public health relevance; skeletal; skeletal disorder; substantia spongiosa; therapeutic target; transcription factor

DESCRIPTION (provided by applicant): Osteocytes are osteoblast-derived cells that are progressively entombed in mineralized matrix where they function to regulate skeletal homeostasis; their importance is highlighted both by their relative abundance and by their exceptionally long lifespan. Surprisingly, although osteocytes are known to manifest unique gene expression patterns relative to their osteoblast precursors and, as a consequence, display unique form and function, little is known of the molecular mechanisms that orchestrate their transition from the osteoblast or of the epigenomic and regulomic determinants that are responsible. In addition, although Wnt signaling is known to be a major but differential regulator of osteoblast and osteocyte activities, the majority of the gene targets that comprise the cell-specific activities of this pathway and the mechanisms through which TCF/LEF/b-catenin function to modulate these targets in both cell types remain unknown. Accordingly, the objectives of the first two aims are as follows. Aim 1: Identify the underlying epigenomic and regulomic mechanisms and associated molecular determinants that are responsible on a genome-wide scale for the osteoblast to osteocyte transition both in vitro and ex vivo. Aim 2: Examine and contrast the impact of the Wnt signaling pathway on osteoblast- and mature osteocyte-specific gene expression patterns and assess the molecular mechanisms through which these gene subsets are modulated directly by b-catenin and impacted by PTH and 1,25(OH)2D3 both in vitro and ex vivo. Our preliminary data and that of others have shown that a number of genes are upregulated during the osteocyte transition, including Sost, Fgf23, Tnfsf11, and Enpp1/3. The Sost gene, which encodes the Wnt pathway antagonist sclerostin (SCL), is of primary importance, however, due to its central biological actions on bone formation, its impact in disease, and its relevance as a potential therapeutic target. Progress has been made in understanding Sost regulation, prompted in part by the discovery that deletion of a downstream Sost enhancer alters Sost expression and is responsible for Van Buchem disease. Our preliminary data, however, suggest significant additional complexity, thus supporting the final objective of this proposal. Aim 3: Assess the molecular mechanisms that underlie both basal and regulated osteocyte expression of Sost at both epigenomic and regulomic levels in both in vitro and in vivo models. Osteocytes play unique roles in the skeleton and act in endocrine fashion to elaborate both local paracrine factors such as sclerostin and systemically active hormones such as FGF23. Pathologic consequences arising from aberrant osteocyte function can be catastrophic. Detailed basic insights arising from the proposed studies are likely to provide new routes of therapeutic intervention for a multiplicity of diseases that affect the skeleton.

描述（由申请人提供）：骨细胞是成骨细胞衍生的细胞，它们逐渐被吞噬在矿化基质中，它们起作用以调节骨骼稳态；它们的相对丰度和异常长的寿命都强调了它们的重要性。令人惊讶的是，尽管已知骨细胞相对于其成骨细胞前体表现出独特的基因表达模式，因此，表现出独特的形式和功能，但对从成骨细胞或表观基因组和调节性决定者的分子机制进行了划分的分子机制知之甚少。此外，尽管已知Wnt信号传导是成骨细胞和骨细胞活性的主要但差异调节剂，但大多数基因靶标包括该途径的细胞特异性活性以及TCF/LEF/B-catenin功能以调节两种细胞类型的靶标的机制。因此，前两个目标的目标如下。 AIM 1：确定在整个基因组范围内负责成骨细胞到骨细胞在体外和Ex Vivo上均在整个基因组范围内负责的基本表观基因组和调节性机制以及相关的分子决定因素。 AIM 2：检查和对比Wnt信号通路对成骨细胞和成熟成骨细胞特异性基因表达模式的影响，并评估这些基因子集直接通过B-catenin调节的分子机制，并受PTH和PTH和1,25（OH）2D3（OH）2d3 Into Into和Ex Vivo的影响。我们的初步数据和其他数据表明，在整骨细胞过渡期间，许多基因被上调，包括SOST，FGF23，TNFSF11和ENPP1/3。编码Wnt途径拮抗剂硬化蛋白（SCL）的SOST基因是最重要的，但是，由于其对骨形成的中心生物学作用，其对疾病的影响以及其作为潜在的治疗靶标的相关性。在理解SOST调节方面取得了进展，部分原因是删除下游SOST SOST增强剂会改变较高的表达，并导致Van Buchem疾病。但是，我们的初步数据提出了明显的额外复杂性，因此支持该提案的最终目标。 AIM 3：评估在体外和体内模型中表观基因组和调节素水平的基础和调节水平的基础和调节骨的基础和调节的骨细胞表达的分子机制。骨细胞在骨骼中起着独特的作用，并以内分泌方式起作用，以阐述诸如硬化蛋白和系统活跃的激素（例如FGF23）等局部旁分泌因子。异常骨细胞功能引起的病理后果可能是灾难性的。拟议的研究产生的详细基本见解可能会为多种疾病提供新的治疗干预途径 影响骨骼。