Dynamics of Assembly of Bone Matrix Proteins

骨基质蛋白组装动力学

• 批准号: 7871226
• 负责人: SARAH L DALLAS
• 金额: $ 0.66万
• 依托单位: UNIVERSITY OF MISSOURI KANSAS CITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-14 至 2009-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7871226
• 关键词: Address; Arthritis; Binding; Binding Proteins; Biological Availability; Bone Matrix; Bone remodeling; Cell Culture Techniques; Cell model; Cells; Complex; Computer Analysis; Data; Deposition; Disease; Event; Extracellular Matrix; Extracellular Matrix Proteins; Fibroblasts; Fibronectins; Foundations; Glycoproteins; Growth Factor; Image; In Vitro; Knock-out; Laboratories; Life; Malignant Neoplasms; Measures; Mediating; Modeling; Molecular; Morphogenesis; Movement; Mus; Null Lymphocytes; Osteoblasts; Osteogenesis; Osteoporosis; Pathway interactions; Play; Process; Proteins; Regulation; Reporter; Rheumatoid Arthritis; Role; Site; Skeletal Development; Structure; Supporting Cell; TNFRSF1A gene; Testing; Time; Tissues; Transforming Growth Factor beta; base; bone; cell motility; in vivo; insight; mineralization; molecular imaging; novel; repaired; response; scaffold

DESCRIPTION (provided by applicant): The extracellular matrix (ECM) has classically been viewed as a static scaffold that provides support to cells and tissues. However, recent studies have shown that ECM molecules form highly dynamic structures that continually undergo movement and deformation in response to cell movement. Evidence is accumulating that ECM proteins may also be major regulators of growth factor activity. Fibronectin is one of the earliest ECM proteins to be assembled into the matrix and facilitates assembly of other ECM proteins. Using a fibronectin null cell model we have found that fibronectin is essential for assembly of multiple bone ECM proteins and is required for osteoblast mineralization but not differentiation. Fibronectin is also critical for assembly of latent TGF( binding protein-1 (LTBP1), an important regulator of TGF(, into the ECM. In addition, our recent dynamic imaging studies in living osteoblasts have suggested novel roles for cell movement in bone ECM assembly and reorganization. The proposed studies are centered around two main hypotheses. The first is that fibronectin is a multifunctional regulator of osteoblast function through its effects as an orchestrator of assembly of bone ECM proteins and through regulation of growth factor activity. The second is that dynamic cell movement is essential for the assembly and reorganization of bone ECM proteins. To test these hypotheses complimentary in vitro and in vivo approaches will be used. In Aim 1 we will determine the role of fibronectin in osteoblast function through its role as a regulator of assembly of bone ECM proteins. Fibronectin-null osteoblast culture models will be used in conjunction with a conditional knockout approach to delete fibronectin in the osteoblast lineage. In Aim 2 we will determine the role of fibronectin in regulating TGF( activity in bone via interactions with LTBP1. This will be done using fibronectin null osteoblasts as well as a novel TGF( reporter mouse line that can be used to measure in vivo TGF( activity. In Aim 3 we will determine the dynamics of assembly and reorganization of bone ECM proteins and their interactions with fibronectin and determine the role of cell movement in ECM assembly and reorganization. This will be done using dynamic molecular imaging of bone ECM proteins together with quantification of cell and fibril dynamics by computational analysis. These studies will provide novel insights into the mechanisms of assembly of bone ECM proteins and provide new insights into the complex molecular pathways for ECM regulation of TGF( in bone. The data generated will have important implications for diseases associated with misregulation of TGF(, such as fibrotic diseases, osteoporosis, arthritis and cancer.

描述（由申请人提供）：细胞外基质（ECM）传统上被视为为细胞和组织提供支撑的静态支架。然而，最近的研究表明，ECM 分子形成高度动态的结构，随着细胞运动而不断发生运动和变形。越来越多的证据表明 ECM 蛋白也可能是生长因子活性的主要调节因子。纤连蛋白是最早组装到基质中的 ECM 蛋白之一，并促进其他 ECM 蛋白的组装。使用纤连蛋白无效细胞模型，我们发现纤连蛋白对于多种骨 ECM 蛋白的组装至关重要，并且是成骨细胞矿化所必需的，但不是分化所必需的。纤连蛋白对于将 TGF( 的重要调节剂) 潜在 TGF( 结合蛋白-1 (LTBP1)) 组装到 ECM 中也至关重要。此外，我们最近对活成骨细胞的动态成像研究表明细胞运动在骨 ECM 中发挥新作用组装和重组。 拟议的研究围绕两个主要假设。首先，纤连蛋白是成骨细胞功能的多功能调节剂，通过其作为骨 ECM 蛋白组装的协调者的作用以及通过调节生长因子活性来发挥作用。其次，动态细胞运动对于骨 ECM 蛋白的组装和重组至关重要。为了测试这些假设，将使用互补的体外和体内方法。在目标 1 中，我们将通过纤连蛋白作为骨 ECM 蛋白组装调节剂的作用来确定纤连蛋白在成骨细胞功能中的作用。无纤连蛋白的成骨细胞培养模型将与条件敲除方法结合使用，以删除成骨细胞谱系中的纤连蛋白。在目标 2 中，我们将确定纤连蛋白通过与 LTBP1 相互作用调节骨中 TGF( 活性) 的作用。这将使用纤连蛋白无效成骨细胞以及可用于测量体内 TGF( 的新型 TGF( 报告小鼠系) 来完成。在目标 3 中，我们将确定骨 ECM 蛋白的组装和重组的动力学及其与纤连蛋白的相互作用，并确定细胞运动在 ECM 组装和重组中的作用。使用骨 ECM 蛋白的动态分子成像以及通过计算分析对细胞和原纤维动力学进行定量，这些研究将为骨 ECM 蛋白的组装机制提供新的见解，并为 ECM 调节 TGF 的复杂分子途径提供新的见解。生成的数据将对与 TGF 失调相关的疾病产生重要影响，例如纤维化疾病、骨质疏松症、关节炎和癌症。