Osteoblast differentiation: Interactions of Wnt, Runx2 and FGF

成骨细胞分化：Wnt、Runx2 和 FGF 的相互作用

基本信息

批准号：
7798088
负责人：
THOMAS G BOYER
金额：
$ 29.11万
依托单位：
UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-04-01 至 2013-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7798088
关键词：
Affinity Alleles Binding Binding Sites Biological Assay Biology Bone Development Bone Diseases Bone Tissue Cell Nucleus Cells Characteristics Complex Couples Coupling DNA DNA Binding DNA-Protein Interaction Data Development Event FGFR1 gene FGFR2 gene Felis catus Fibroblast Growth Factor Fibroblast Growth Factor Receptors Gene Expression Gene Expression Profile Gene Mutation Gene Targeting Genes Genetic Transcription Health Human Human Genetics Knock-out Knowledge Laboratory mice Lead Ligands Link Measures Molecular Molecular Profiling Mus Osteoblasts Osteogenesis Osteoporosis Pathway interactions Protein Binding Proteins RNA Interference Receptor Signaling Regulation Signal Transduction Site Staging Surface Plasmon Resonance TCF Transcription Factor Tertiary Protein Structure Testing Therapeutic Thermodynamics Translating Uncertainty beta catenin bone bone mass fibroblast growth factor 18 gain of function improved mouse model new therapeutic target osteoblast differentiation prevent promoter protein protein interaction public health relevance transcription factor

项目摘要

DESCRIPTION (provided by applicant): Studies of mouse and human genetics show that canonical Wnt signaling is required for normal bone development as well as acquisition of normal bone mass. Canonical Wnt signaling is strongly anabolic for bone. Consequently, understanding how canonical Wnt signaling induces bone will illuminate pathways that can be manipulated to increase bone mass for the treatment of osteoporosis. Because canonical Wnt signaling increases the protein levels of beta-catenin (bcat), which then moves to the nucleus and induces gene expression, we hypothesized that bcat cooperates with bone-specific transcription pathways to induce genes responsible for Wnt- induced bone formation. Significantly, in preliminary data we show that fibroblast growth factor 18 (FGF18) expression requires and is directly induced by canonical Wnt signaling. Moreover, the osteoblast-specific transcription factor, Runx2, binds to the Wnt-dependent transcription factor LEF/TCF and thereby stimulates the FGF18 promoter. Thus, FGF18 expression is directly linked to bone-specific and Wnt-dependent transcription. Given these direct links to the essential pathways of bone, we hypothesize that induction of FGF18 is required for the anabolic effects of Wnt signaling in bone. We further hypothesize that the Runx2-LEF/TCF transcription complex regulates a set of genes that induce a specific early stage of osteoblast differentiation. To test our hypotheses and advance new therapies for bone disease we will pursue the following specific aims: 1) determine the protein domains and thermodynamic parameters that govern assembly of the Runx2-LEF complex and its affinity for DNA, 2) identify osteoblast-relevant genes that are turned on (or off) by the convergence of Wnt signaling and Runx2, and 3) using mice with conditional loss and gain of function alleles for bcat define the requirement for FGFs and FGF signaling during canonical Wnt-induced osteoblast differentiation. These studies will provide an unprecedented view of the molecular events regulating osteoblast gene expression in respose to Wnt and FGF. Additionally, these studies will unravel how Wnt signaling induces formation of bone and in cooperation with other transcription factors regulates specific steps in the sequence of osteoblast differentiation. We anticipate that the completion of these studies will suggest new way to treating bone diseases like osteoporosis. PUBLIC HEALTH RELEVANCE. This application aims to improve human health by advancing our understanding of the bone and bone producing cells. The completion of these studies will reveal new therapeutic targets and ways for treating bone disease like osteoporosis.

描述（由申请人提供）：对小鼠和人类遗传学的研究表明，规范的 Wnt 信号传导是正常骨骼发育以及正常骨量获得所必需的。典型的 Wnt 信号传导对于骨骼具有强烈的合成代谢作用。因此，了解经典 Wnt 信号传导如何诱导骨骼将阐明可操纵增加骨量以治疗骨质疏松症的途径。由于经典的 Wnt 信号传导会增加 β-连环蛋白 (bcat) 的蛋白质水平，然后该蛋白会移动到细胞核并诱导基因表达，因此我们假设 bcat 与骨特异性转录途径合作，诱导负责 Wnt 诱导骨形成的基因。值得注意的是，在初步数据中，我们表明成纤维细胞生长因子 18 (FGF18) 的表达需要典型的 Wnt 信号传导，并且由典型的 Wnt 信号传导直接诱导。此外，成骨细胞特异性转录因子 Runx2 与 Wnt 依赖性转录因子 LEF/TCF 结合，从而刺激 FGF18 启动子。因此，FGF18 表达与骨特异性和 Wnt 依赖性转录直接相关。鉴于这些与骨的重要途径的直接联系，我们假设 FGF18 的诱导对于骨中 Wnt 信号的合成代谢作用是必需的。我们进一步假设 Runx2-LEF/TCF 转录复合物调节一组诱导成骨细胞分化的特定早期阶段的基因。为了测试我们的假设并推进骨病的新疗法，我们将追求以下具体目标：1) 确定控制 Runx2-LEF 复合物组装及其对 DNA 亲和力的蛋白质结构域和热力学参数，2) 识别成骨细胞相关基因通过 Wnt 信号传导和 Runx2 的融合来打开（或关闭），3) 使用具有 bcat 功能等位基因条件性丧失和获得的小鼠定义了规范过程中对 FGF 和 FGF 信号传导的要求Wnt诱导的成骨细胞分化。这些研究将为调节成骨细胞基因表达以应对 Wnt 和 FGF 的分子事件提供前所未有的视角。此外，这些研究将揭示 Wnt 信号如何诱导骨形成，并与其他转录因子合作调节成骨细胞分化序列中的特定步骤。我们预计这些研究的完成将为治疗骨质疏松症等骨疾病提供新方法。公共卫生相关性。该应用旨在通过增进我们对骨和骨生成细胞的了解来改善人类健康。这些研究的完成将揭示治疗骨质疏松症等骨病的新治疗靶点和方法。