The Role of Scleraxis and Mechanical Loading on Enthesis Maturation

巩膜和机械负荷对附着点成熟的作用

• 批准号: 8839713
• 负责人: MEGAN Leigh KILLIAN
• 金额: $ 3.78万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-05-28 至 2015-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8839713
• 关键词: Adipose tissue; Adolescent; Affect; Automobile Driving; BMP-12; Biological Factors; Birth; Botulinum Toxins; Brachial plexus structure; Cells; Collagen; Cues; Defect; Denervation; Development; Differentiation and Growth; Disease; Embryo; Embryonic Development; Engineering; Excision; Experimental Models; Extracellular Matrix; Fibroblasts; Fibrocartilages; Genes; Goals; Growth Factor; Health; Homeostasis; Impairment; In Vitro; Joints; Knock-out; Lead; Life; Link; Mechanics; Mediating; Mesenchymal Stem Cells; Methods; Modeling; Molecular; Motion; Mus; Muscle; Musculoskeletal Development; Nature; Neonatal; Nerve; Orthopedics; Outcome; Paralysed; Physical condensation; Play; Property; Rehabilitation therapy; Role; Shoulder; Skeleton; Small Interfering RNA; Stem cells; Stress; Structure; Tendinopathy; Tendon structure; Testing; Time; Tissue Engineering; Tissues; Transforming Growth Factor beta; Vaginal delivery procedure; bone; fetal; fibrillogenesis; functional outcomes; gene therapy; improved; in vivo; in vivo Model; interest; mechanical drive; mineralization; novel strategies; repaired; response; scleraxis; stem cell differentiation; supraspinatus muscle; tendon development; transcription factor

DESCRIPTION (provided by applicant): The development of a functional attachment between tendon and bone (the "enthesis") is critical for transmitting muscle forces to bone for joint motion. The formation of this attachment is driven by mechanical and biologic factors. Murine models of have demonstrated that removal of muscle load dramatically impairs the development of the enthesis. Furthermore, deletion of scleraxis (Scx), a transcription factor necessary for the development of force-transmitting tendons, leads to defects in enthesis formation. However, the mechanisms driving the mechanosensitivity of enthesis development are not known. Our global hypothesis is that Scx necessary for enthesis development and is driven by mechanical cues during. The first aim of this study is to determine the temporal influence of Scx on neonatal enthesis maturation using an inducible knockout murine model. Expression of Scx will be limited to development up to embryonic day 15.5, post-natal day 1, or post-natal day 7 and developmental adaptations and maturation of the enthesis will be assessed throughout juvenile development. It is expected that deletion of Scx during embryonic development will have a greater effect on enthesis maturation compared to post-natal deletion, and molecular and functional outcomes will be correlated with duration of Scx expression during maturation. These findings will establish the importance of Scx in enthesis development as well as determine its temporal role in post- natal musculoskeletal development. The second aim of this study is to determine the necessity of mechanical loading on Scx expression during development. Using in vivo and in vitro methods, we plan to mimic unloading and overloading, respectively, as well as assess the mechanosensitivity of Scx and its role in maturation and function of the enthesis. Using previously validated models of in vivo unloading and tissue-engineered methods for in vitro dynamic loading, we will track Scx-expressing cells as well as potential differentiation of ASCs into tenocytes. The effect of perturbed loading on the molecular and morphological response of Scx-expressing cells will be correlated with adaptations in structure and function using mechanical tests. These findings will determine the role of mechanical loading in Scx expression as well as the necessity of Scx in mechanically- induced tenogenesis. Lastly, the potency of Scx in load-induced tenogenesis following modulation with growth factors such as BMP-12 will be confirmed using BMP-12 siRNA. Findings from these studies will establish the importance of Scx on post-natal enthesis development, the mechanoresponsiveness of Scx in multi-tiered experimental models, and ultimately lead to new approaches for investigating musculoskeletal development and tissue engineered strategies for mechanosensitive orthopaedic tissues.

描述（由申请人提供）：肌腱和骨骼之间的功能附着的发展（“灌肠”）对于将肌肉力传递到骨头以进行关节运动至关重要。这种依恋的形成是由机械和生物学因素驱动的。鼠模型表明，去除肌肉负荷会极大地损害灌感的发展。此外，硬化（SCX）的缺失，这是一种转录因子 力传输肌腱的发展，导致衰减形成中的缺陷。然而，尚不清楚推动埃文发育机械敏感性的机制。我们的全球假设是，SCX对于分发开发所需，并由机械线索驱动。这项研究的第一个目的是确定SCX使用诱导型敲除鼠模型对新生儿源成熟的时间影响。 SCX的表达将仅限于胚胎第15.5天，产后第1天，或产后第7天以及整个少年发育的发育适应和成熟。可以预期，与产后缺失相比，胚胎发育过程中SCX的缺失将对源成熟产生更大的影响，并且分子和功能结果将与成熟过程中SCX表达的持续时间相关。这些发现将确定SCX在ENTEMES发展中的重要性，并确定其在后肌肉骨骼发育中的时间作用。这项研究的第二个目的是确定开发过程中SCX表达的机械负载的必要性。使用体内和体外方法，我们计划分别模仿和超载，并评估SCX的机械敏感性及其在Enthesis的成熟和功能中的作用。使用先前验证的体内卸载和组织工程方法的模型，用于体外动态载荷，我们将跟踪表达SCX的细胞以及ASC的潜在分化为TenCytes。扰动载荷对表达SCX细胞的分子和形态反应的影响将与使用机械测试的结构和功能的适应性相关。这些发现将确定机械负荷在SCX表达中的作用以及SCX在机械诱导的肾脏中的必要性。最后，使用BMP-12 siRNA确认SCX在调节后与BMP-12等生长因子（例如BMP-12）进行调节后的肾脏效力。这些研究的发现将确定SCX对多层实验模型中SCX的机械响应性的重要性，并最终导致了研究肌肉骨骼发育的新方法以及针对机械敏感矫形器组织的肌肉骨骼工程策略。