Transcriptional regulation of tendon differentiation and matrix formation

肌腱分化和基质形成的转录调控

• 批准号: 8034242
• 负责人: RONEN SCHWEITZER
• 金额: $ 33.26万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-01 至 2015-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8034242
• 关键词: Address; Affect; Attention; Back; Binding Proteins; Biochemistry; Biomechanics; Bypass; Caliber; Cells; Clinical; Collagen; Collagen Fibril; Degenerative Disorder; Economic Burden; Embryo; Embryonic Development; Event; Extracellular Matrix Proteins; Extracellular Protein; Failure; Fiber; Gene Expression; Gene Targeting; Genes; Genetic; Genetic Programming; Goals; Growth; Healed; Individual; Injury; Laboratories; Ligaments; Link; Mediator of activation protein; Modification; Mohawk Indian; Molecular; Muscle Contraction; Musculoskeletal System; Mutation; Organ Transplantation; Orthopedics; Outcome; Phase; Phenotype; Play; Process; Property; Proteins; Recovery; Regulation; Regulatory Pathway; Role; Skeleton; Societies; Sports; Staging; Structure; Tendon Injuries; Tendon structure; Tensile Strength; Testing; Tissues; Transcriptional Regulation; Transgenic Organisms; Translating; Zinc Fingers; age related; base; cohort; fibrillogenesis; healing; ligament injury; mutant; overexpression; postnatal; public health relevance; rapid growth; reconstitution; research study; scleraxis; transcription factor

DESCRIPTION (provided by applicant): Tendons transmit the force generated by muscle contraction to the skeleton, through robust and highly organized bundles of collagen fibrils that establish the biomechanical properties of tendons. In the tendons, cellular extensions engulf bundles of collagen fibrils and generate the microenvironment for fibril growth. Growth of the collagen fibrils in tendons is the single most significant factor that determines biomechanical properties and tensile strength of tendons. Collagen fibril growth occurs in two phases, slow fibril assembly in embryonic stages and a much faster pace of fibril growth that likely occurs through fibril fusion in postnatal stages. Nothing, however, is known about the genetic program that regulates these processes. We have previously shown that the bHLH transcription factor Scleraxis is essential for early tendon differentiation and that it likely also plays an important role in collagen fibrillogenesis. In mutants of a second tendon transcription factor, Mohawk, we now find a failure of the later postnatal phase of collagen fibril growth. This project focuses on the role of Scleraxis and Mohawk in collagen fibrillogenesis and tendon maturation. The first specific aim focuses on tendon assembly in embryonic tendons and the second aim looks at the regulation of tendon maturation and rapid collagen fibril growth in postnatal stages. These processes will be addressed following a similar approach in both stages. Normal tendon growth and tendon phenotypes will initially be evaluated with an enhanced set of structural parameters and the effects of overexpression of Scx or Mkx on tendon growth will be examined. Molecular mediators of Scleraxis and Mohawk functions will be identified by microarray profiling and the regulatory roles of a small number of target genes will be determined by a transgenic rescue of the Scx or Mkx phenotypes reintroducing the expression of a single or multiple target genes into the mutant background. We recently identified ZFP185, a Zinc Finger Transcription factor as the first promising candidate for which we plan to proceed with a transgenic rescue. Identifying regulatory pathways that control fibril growth will likely contribute to the ability to enhance and regulate these processes in clinical settings. PUBLIC HEALTH RELEVANCE: Sports and age related tendon or ligament injuries are of the most common causes for orthopedic treatments and the long healing periods for these injuries translate to considerable hardship to the affected individuals and a significant economic burden for society. The capacity to return these tissues to their original strength is tightly linked to the quality of the collagen matrix that develops in the treated tissue. Considerable attention has therefore been directed to the proteins that make up the collagen fibrils in tendons and to the extracellular proteins that regulate fibril growth. Nothing however is known about the higher levels of regulation of these processes. The long term goal of this project is to decipher the transcriptional network that governs collagen fibrillogenesis and fibril growth in tendons and ligaments. Identifying the key regulatory players in this process is likely to open new avenues for enhancement of the clinical outcomes of tendon and ligament injury or replacement.

说明(申请人提供)：肌腱将肌肉收缩产生的力传递到骨骼，通过牢固和高度组织化的胶原纤维束建立肌腱的生物力学特性。在肌腱中，细胞延伸吞噬了一束束的胶原纤维，并为纤维生长创造了微环境。肌腱中胶原纤维的生长是决定肌腱生物力学性能和抗拉强度的最重要因素。胶原原纤维的生长有两个阶段，胚胎阶段的缓慢纤维组装和较快的纤维生长速度，这可能是在出生后阶段通过纤维融合发生的。然而，人们对调控这些过程的遗传程序一无所知。我们先前已经证明，bHLH转录因子硬化轴在肌腱早期分化中是必不可少的，它可能在胶原纤维形成中也起着重要作用。在第二个肌腱转录因子莫霍克的突变中，我们现在发现了出生后后期胶原纤维生长的失败。本项目的重点是硬化轴和莫霍克在胶原纤维形成和肌腱成熟中的作用。第一个特定的目标是在胚胎肌腱中组装肌腱，第二个目标是在出生后阶段肌腱成熟和胶原纤维的快速生长的调节。这些进程将在两个阶段采取类似的办法加以处理。正常的肌腱生长和肌腱表型最初将通过一套增强的结构参数进行评估，并将检查SCX或MKX过表达对肌腱生长的影响。通过微阵列分析鉴定Skeraxis和Mohawk功能的分子介体，并通过对SCX或MKX表型的转基因挽救将单个或多个靶基因的表达重新引入突变背景来确定少数靶基因的调节作用。我们最近确定了ZFP185，一种锌指转录因子，是我们计划进行转基因救援的第一个有希望的候选基因。确定控制原纤维生长的调节途径可能有助于在临床环境中增强和调节这些过程的能力。 公共卫生相关性：与运动和年龄有关的肌腱或韧带损伤是骨科治疗的最常见原因，这些损伤的漫长愈合期给受影响的个人带来了相当大的困难，给社会带来了巨大的经济负担。将这些组织恢复到其原始强度的能力与在处理组织中形成的胶原基质的质量密切相关。因此，相当多的注意力集中在肌腱中构成胶原纤维的蛋白质和调节纤维生长的细胞外蛋白质上。然而，对于这些过程的更高级别的监管，我们一无所知。这个项目的长期目标是破译控制肌腱和韧带中胶原纤维生成和纤维生长的转录网络。确定这一过程中的关键调控因素可能会为提高肌腱和韧带损伤或置换的临床结果开辟新的途径。