Modulation of Bone Formation by SHN3

SHN3 对骨形成的调节

• 批准号: 9561942
• 负责人: Matthew Blake Greenblatt
• 金额: $ 42.38万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-18 至 2020-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9561942
• 关键词: Adaptor Signaling Protein; Address; Adoption; Affect; Age; Alleles; American; Area; Binding; Biosensor; Bone Diseases; Cell Lineage; ChIP-seq; Chromatin; Complex; DNA Binding; DNA-Binding Proteins; Data; Disease; Disease model; Dose; Epigenetic Process; Equilibrium; Feedback; Fracture; Fracture Healing; Genes; Genetic; Gold; Hip Fractures; Human; Kinetics; Knock-in; Knowledge; Mesenchymal Stem Cells; Metabolic Bone Diseases; Methods; Mitogen-Activated Protein Kinases; Modeling; Molecular; Morbidity - disease rate; Mus; Mutation; Names; Osteoblasts; Osteoclasts; Osteogenesis; Osteoporosis; Ovariectomy; Pathology; Pathway interactions; Phenocopy; Postmenopausal Osteoporosis; Regulation; Reporting; Risk; Role; Series; Shapes; Signal Transduction; Study models; Testing; WNT Signaling Pathway; Woman; Work; arm; base; bone; bone loss; bone mass; career development; embryonic stem cell; experience; experimental study; in vivo; inhibitor/antagonist; innovation; lifetime risk; malignant breast neoplasm; medical schools; men; mortality; mouse model; novel; novel strategies; osteoblast differentiation; osteoporosis with pathological fracture; phosphoproteomics; promoter; public health relevance; research and development; response; scaffold; skeletal; skeletal disorder; therapeutic target

 DESCRIPTION (provided by applicant): Previously we found that the adapter protein SHN3 had a major effect to suppress bone formation by osteoblasts in vivo by inhibiting the activity of the mitogen activated protein kinase (MAPK) ERK. We also identified that WNTs have a previously unidentified activity to activate this SHN3/ERK pathway. Here we seek to make critical extensions of these observations by determining how SHN3 inhibits ERK and how this pathway influences models of skeletal disease in vivo. This area of study is significant as osteoporosis is a highly prevalent disorder of low bone mass and skeletal fragility. Half of all women will experience of an osteoporotic fracture during their lifetime, with each of these fractures incurring significant morbidity and mortality. Based on the profound ability of SHN3 to suppress bone formation, building a better understanding of this pathway will yield new methods to control the activity of osteoblasts to form bone, potentially offering approaches to treat osteoporosis and other disorders of low bone mass. The three overlapping areas to be investigated in this project are: 1. Determine the contribution of SHN3 to skeletal disease models while we have established that SHN3 strongly suppresses bone formation in mice at baseline, the specific contribution of SHN3 to murine models of post-menopausal osteoporosis and skeletal fracture are unknown and will be studied in SHN3-deficient mice. 2. Determine how SHN3 inhibits the ERK pathway in osteoblasts While we have established that SHN3 acts in osteoblasts primarily by suppressing the activity of ERK, the relevant ERK substrates and how SHN3 shapes the kinetics of the ERK response are unknown and will be studied using phosphoproteomics and a quantitative ERK activity biosensor. Determining the relevant substrates of ERK may identify downstream effectors of the SHN3/ERK pathway that are themselves amenable to therapeutic targeting. Additionally, the mechanism for the activation of the ERK/SHN3 pathway by WNTs is unknown, and this will be addressed by a focused screen to determine the MAP3K required for proximal activation of this pathway. 3. Determine if chromatin acts as a scaffold to orchestrate the activity of the SHN3/ERK complex in osteoblasts. Both SHN3 and ERK have previously been identified to bind DNA, raising the possibility that regulation of ERK activity by SHN3 occurs in chromatin bound complexes. In this aim, a complimentary series of chromatin immunoprecipitation-sequencing experiments will be utilized to explore if chromatin orchestrates the function of the SHN3/ERK pathway.

 描述(申请人提供)：此前，我们发现适配蛋白SHN3通过抑制丝裂原活化蛋白激酶(MAPK)ERK的活性，在体内抑制成骨细胞的骨形成。我们还发现WNTs具有一种先前未知的激活SHN3/ERK途径的活性。在这里，我们试图通过确定SHN3如何抑制ERK以及这一途径如何影响体内骨骼疾病的模型来对这些观察进行关键的扩展。这一领域的研究意义重大，因为骨质疏松症是一种非常普遍的低骨量和骨骼脆性疾病。一半的女性会在一生中经历骨质疏松性骨折，每一次骨折都会导致显著的发病率和死亡率。基于SHN3抑制骨形成的深刻能力，更好地了解这一途径将产生控制成骨细胞形成骨的新方法，可能为治疗骨质疏松症和其他低骨量疾病提供途径。本项目中要研究的三个重叠领域是：1.确定SHN3在骨骼疾病模型中的贡献虽然我们已经确定SHN3在基线水平上强烈抑制小鼠的骨形成，但SHN3对绝经后骨质疏松症和骨骼骨折模型的具体贡献尚不清楚，将在SHN3缺陷小鼠中进行研究。2.确定SHN3如何抑制成骨细胞中的ERK信号转导途径我们已经确定SHN3主要通过抑制ERK的活性在成骨细胞中发挥作用，相关的ERK底物以及SHN3如何影响ERK反应的动力学尚不清楚，将使用磷酸化蛋白质组学和ERK活性定量生物传感器进行研究。确定ERK的相关底物可以确定SHN3/ERK通路的下游效应物，这些效应物本身就是治疗靶向的。此外，WNTs激活ERK/SHN3途径的机制尚不清楚，这将通过一个聚焦屏幕来确定该途径的近端激活所需的MAP3K。3.确定染色质是否作为支架来协调成骨细胞中SHN3/ERK复合体的活动。SHN3和ERK都已被发现与DNA结合，这增加了SHN3对ERK活性的调节发生在染色质结合的复合体中的可能性。为此，将利用一系列染色质免疫沉淀-测序实验来探索染色质是否协调SHN3/ERK途径的功能。