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Modulation of RUNX2 Activity by ERa in Osteoblasts

ERa 对成骨细胞中 RUNX2 活性的调节

基本信息

批准号：
9503274
负责人：
BARUCH FRENKEL
金额：
$ 19.52万
依托单位：
UNIVERSITY OF SOUTHERN CALIFORNIA
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-04-01 至 2019-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9503274
关键词：
Affect Binding Biological Assay Bone Resorption CRISPR/Cas technology Cell Line Cells ChIP-seq Chromatin Code Computer Analysis Computer Simulation DNA Sequence Data Data Analyses Dependency Development Equilibrium Estradiol Estrogen Receptor alpha Estrogens Europe Female Fracture Funding Future Gene Targeting Genes Genetic Transcription Genome Genomics Gonadal Steroid Hormones Histones Human Investigation Knockout Mice Lasofoxifene Ligands Light Location Malignant Neoplasms Mediating Modeling Molecular Mus Osteoblasts Osteoclasts Osteogenesis Outcome Pharmaceutical Preparations Play Positioning Attribute Postmenopausal Osteoporosis Postmenopause Property Protein Hormone Receptor Publishing Raloxifene Recruitment Activity Reporter Reporting Risk Role Selective Estrogen Receptor Modulators Shapes Signal Transduction Site Spinal Fractures Testing Transcriptional Regulation Validation Work base bone bone cell bone loss bone mass bone turnover cell type combinatorial cortical bone experience functional outcomes genome editing genome wide association study genome-wide genomic data high throughput analysis histone modification insight novel osteoblast differentiation osteoclastogenesis osteoporosis with pathological fracture overexpression predictive modeling prevent prospective protein protein interaction public health relevance runx proteins spine bone structure substantia spongiosa tool transcription factor transcriptome sequencing whole genome

项目摘要

ABSTRACT: Modulation of RUNX2 Activity by ER in Osteoblasts The bone-sparing properties of estrogens are mediated by ER in a variety of cell types, including cells of the osteoblast and osteoclast lineages, but the underlying molecular mechanisms are poorly understood. In particular, there are contrasting reports on how estradiol (E2) affects RUNX2, an osteoblast master regulator that has been implicated in human bone mass control through GWAS. RUNX2 plays critical roles in the osteoblast lineage to stimulate both autonomous cellular differentiation (and thus bone formation) and osteoblast-driven osteoclastogenesis (and thus bone resorption). While this project initiated with a focus on inhibition of RUNX2 by E2, the present renewal application aims to take genome-wide approaches to understand why E2 does not inhibit RUNX2-driven transcription uniformly. We show that RUNX2 activity upon various targets is modulated differently, with most targets inhibited, but others not inhibited and some even cooperatively stimulated, to various extents, by RUNX2 and E2. Locus-dependent differential modulation of RUNX2 is expected to ultimately change the balance between RUNX2-mediated osteoblast differentiation and RUNX2-mediated osteoblast-driven osteoclastogenesis. Our preliminary data also demonstrate that both raloxifen and lasofoxifene poorly mimic E2 in modulating activity of RUNX2 at different loci. Mechanisms underlying the locus- and ligand-dependent modulation of RUNX2 by ER are completely unknown. Based on our preliminary results, we hypothesize that ER differentially modulates RUNX2 across the osteoblast genome depending on local relative positions of sites occupied by RUNX2 and ER and the ER ligand. Additionally, we hypothesize that local collaborating transcription factors (TFs), as well as specific cognate motif sequences for RUNX2, ER and collaborating TFs shape local effects of ER on RUNX2. We will first investigate by ChIP-seq analysis of histone marks how E2 modulates RUNX2-driven changes to the chromatin activation status at every genomic locus. The mutual effects of ER and RUNX2 on occupying their target loci will also be determined genome-wide by ChIP-seq. Computational models will then be developed to explain the locus-specific combinatorial transcriptional regulation by RUNX2 and ER. These models will be tested, first computationally and then experimentally, for their ability to predict effects of E2 on RUNX2 activity. Finally, since ER in pre-osteoblasts protects female cortical bone in mice, and since raloxifen and lasofoxifene, SERMs commonly prescribed in the US and in Europe, respectively, only reduce the risk for vertebral (predominantly trabecular) osteoporotic fractures, but not non-vertebral fractures, we will also decode how raloxifene- and lasofoxifene-bound ER modulate RUNX2 activity genome wide. Principal genomic determinants will be identified, which explain the differential modulation of RUNX2 activity as a function of the locus (different targets) and the ligand (E2 vs. raloxifen vs. lasofoxifene). This project will help understand how E2 differentially modulates RUNX2 activity at different loci to potentially alter the balance between bone formation and bone resorption. Gene sets will be identified where SERMs mimic, or do not mimic E2. While unveiling the underlying genomic codes, tools will be generated for future investigation of how E2, or any SERM, modulate RUNX2 activity at prototypic loci to differentially regulate specific gene sets.

摘要：成骨细胞中ER β对RUNX 2活性的调节雌激素的骨保护特性是由多种细胞类型中的ER β介导的，包括成骨细胞和破骨细胞谱系，但基本的分子机制知之甚少。在特别是，有关于雌二醇（E2）如何影响RUNX 2（成骨细胞主调节因子）的对比报告通过GWAS控制人体骨量。RUNX 2在成骨细胞谱系刺激自主细胞分化（从而骨形成）和成骨细胞驱动的破骨细胞生成（从而骨吸收）。虽然这个项目的重点是由于E2对RUNX 2的抑制，本更新申请旨在采用全基因组方法，理解为什么E2不能均匀地抑制RUNX 2驱动的转录。我们发现RUNX 2的活性对各种靶点的调节不同，大多数靶点被抑制，但其他靶点未被抑制，甚至在不同程度上由RUNX 2和E2协同刺激。轨迹相关微分 RUNX 2的调节预期最终改变RUNX 2介导的成骨细胞之间的平衡，分化和RUNX 2介导的成骨细胞驱动的破骨细胞生成。我们的初步数据还这表明雷洛昔芬和拉索昔芬在不同浓度下在调节RUNX 2活性方面均不能很好地模拟E2，的位点ER介导的RUNX 2基因座和配体依赖性调节的潜在机制是完全未知基于我们的初步结果，我们假设ER β在细胞内不同程度地调节RUNX 2。成骨细胞基因组取决于RUNX 2和ER β占据的位点的局部相对位置以及ER 配体。此外，我们假设，本地协作转录因子（TF），以及特定的 RUNX 2、ER β和协作TF的同源基序序列形成ER β对RUNX 2的局部作用。我们将首先通过ChIP-seq分析研究组蛋白标记E2如何调节RUNX 2驱动的变化，每个基因组位点的染色质激活状态。ER β和RUNX 2在占位性病变中的相互作用它们的靶基因座也将通过ChIP-seq在全基因组范围内确定。然后，计算模型将 RUNX 2和ER β的基因座特异性组合转录调控。这些模型将被测试，首先计算，然后实验，他们的能力，以预测E2的影响， RUNX 2活动。最后，由于前成骨细胞中的ER β可以保护小鼠的雌性皮质骨，雷洛昔芬和拉索昔芬是美国和欧洲分别常用的SERM，椎体（主要是骨小梁）骨质疏松性骨折的风险，而非非椎体骨折，我们将还解码了雷洛昔芬和拉索昔芬结合的ER β如何在全基因组范围内调节RUNX 2活性。主要将确定基因组决定簇，这解释了RUNX 2活性的差异调节，基因座（不同靶点）和配体（E2 vs.雷洛昔芬vs.拉索昔芬）的功能。这个项目将有助于了解E2如何在不同位点差异调节RUNX 2活性，从而潜在地改变平衡骨形成和骨吸收之间的联系将在SERM模拟或不模拟的情况下鉴定基因集。模拟E2。在揭示潜在的基因组密码的同时，将为未来的研究提供工具， E2或任何SERM如何在原型基因座调节RUNX 2活性以差异调节特定基因组。