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Mechanisms of growth plate organization in response to mechanical load

生长板组织响应机械载荷的机制

基本信息

批准号：
9765151
负责人：
Rosa A. Serra
金额：
$ 16.34万
依托单位：
UNIVERSITY OF ALABAMA AT BIRMINGHAM
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-01 至 2022-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9765151
关键词：
Actins Address Adenovirus Vector Adhesions Affect Architecture Biological Assay Biological Process Bone Growth Bone remodeling Cell Enlargement Cell Proliferation Cell division Cell surface Cell-Cell Adhesion Cell-Matrix Junction Cells Cellular Assay Cerebral Palsy Child Chondrocytes Complex Consumption Cytoskeleton Data Defect Deposition Destinations Disease Dose Epiphysial cartilage Fluorescence Resonance Energy Transfer Focal Adhesions Force of Gravity Future Growth Hemiplegia Hindlimb Suspension Hypertrophy Imaging Techniques Integrins Lead Leg Length Limb structure Link Measures Mediating Methods Modeling Molecular Molecular Genetics Mus N-Cadherin Organ Culture Techniques Osteogenesis Paralysed Pathway interactions Periodicity Pharmacology Physiological Play Poliomyelitis Process Protein Dynamics Proteins Resolution Role Rotation Shapes Site Structure Surface System Testing Time Tissues Vinculin Weight Work base bone cartilaginous daughter cell in vivo in vivo Model indexing integrin-linked kinase live cell imaging mechanical load migration response sensor skeletal tissue spatiotemporal

项目摘要

Longitudinal growth of limbs occurs through cartilaginous structures called the growth plate at the ends of each bone in a process called endochondral bone formation. One important feature of the growth plate is that the cells in the tissue align into columns. While the magnitude of bone growth is dependent on cell proliferation, matrix deposition, and cell enlargement during hypertrophy, the columns allow directional growth of the bone. It was noted that a large proportion of children with paralysis in one leg as a result of poliomyelitis or hemiplegic cerebral palsy demonstrated significant limb length discrepancy with the paralyzed limb being shorter than the other limb. Based on these observations we hypothesized that mechanical load regulates the function of the growth plate. While the effects of mechanical load on bone remodeling have been studied extensively, little was known about the role of loading on endochondral bone formation and limb length determination so we developed in vivo models for removing mechanical load on hind limb in young mice via paralysis. Loss of mechanical load resulted in shortening of the paralyzed limb, disorganization of the columnar architecture in the growth plate, and disruption to the cortical actin structure within the cells. Very little is known about how chondrocytes align themselves into this columnar structure because isolated chondrocytes in culture do not align into columns and in vivo models are time consuming and expensive to work with. In addition, there are limited methods to view the biological processes involved in real time. In this R21proposal we plan to address a critical barrier in the field and develop an ex vivo organ culture system and live cell imaging assays to measure changes in protein localization and tension at cellCcell and cellCmatrix adhesion sites during column formation in real time. We will then illustrate how the mechanisms involved in column formation in loaded and unloaded conditions can be analyzed in detail using these assays. Understanding the molecular mechanisms that govern how mechanical load affects growth plate function would be expected to inform future strategies for treating various types of limb length disorders.

四肢的纵向生长是通过软骨结构发生的，称为生长板，在一个叫做软骨内骨形成的过程中，的一个重要特征生长板的一个特点是组织中的细胞排列成柱状。虽然骨骼生长的幅度依赖于细胞增殖、基质沉积和细胞肥大，圆柱允许骨的定向生长。据指出，有很大一部分儿童，小儿麻痹症或偏瘫性脑性麻痹导致的一条腿瘫痪肢体长度差异明显，瘫痪肢体短于另一肢体。基于这些观察，我们假设机械负荷调节了生长板而机械负荷对骨重建的影响已被研究广泛地说，关于载荷对软骨内骨形成和四肢骨形成的作用知之甚少。因此，我们开发了体内模型，用于消除后肢上的机械负荷，年轻的老鼠通过瘫痪。机械负荷的丧失导致瘫痪肢体缩短，生长板柱状结构紊乱，皮质破坏细胞内的肌动蛋白结构。关于软骨细胞是如何排列成这种柱状结构是因为培养中分离的软骨细胞不排列成柱状，体内模型的使用是耗时且昂贵的。此外，还有一些方法，来观察真实的生物过程。在本R21提案中，我们计划解决该领域的关键障碍，并开发离体器官培养系统和活细胞成像测定细胞-细胞和细胞-基质粘附时蛋白定位和张力变化的试验在真实的时间柱形成过程中的位置。然后，我们将说明如何参与的机制，可以使用这些分析详细分析在加载和未加载条件下的柱形成。了解控制机械负荷如何影响生长板的分子机制该功能有望为未来治疗各种类型肢体长度的策略提供信息紊乱