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: 8212156
• 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/8212156
• 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.

描述（由申请人提供）：肌腱通过坚固且高度组织化的胶原原纤维束将肌肉收缩产生的力传递到骨骼，这些胶原原纤维束建立了肌腱的生物力学特性。在肌腱中，细胞延伸吞噬胶原纤维束并为纤维生长产生微环境。肌腱中胶原纤维的生长是决定肌腱生物力学特性和拉伸强度的最重要因素。胶原原纤维的生长分两个阶段进行，胚胎阶段原纤维组装缓慢，出生后阶段原纤维融合可能发生更快的原纤维生长速度。然而，我们对调节这些过程的遗传程序一无所知。我们之前已经表明，bHLH 转录因子 Scleraxis 对于早期肌腱分化至关重要，并且它可能在胶原纤维形成中也发挥重要作用。在第二种肌腱转录因子莫霍克的突变体中，我们现在发现出生后后期胶原纤维生长失败。该项目重点研究 Scleraxis 和 Mohawk 在胶原纤维生成和肌腱成熟中的作用。第一个具体目标侧重于胚胎肌腱中的肌腱组装，第二个目标着眼于出生后阶段肌腱成熟和胶原纤维快速生长的调节。这些过程将在两个阶段采用类似的方法来解决。首先将使用一组增强的结构参数来评估正常肌腱生长和肌腱表型，并将检查 Scx 或 Mkx 过度表达对肌腱生长的影响。 Scleraxis 和 Mohawk 功能的分子介质将通过微阵列分析来鉴定，少数靶基因的调节作用将通过 Scx 或 Mkx 表型的转基因拯救来确定，将单个或多个靶基因的表达重新引入突变背景。我们最近发现 ZFP185（一种锌指转录因子）是第一个有希望的候选因子，我们计划对其进行转基因拯救。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：运动和年龄相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会给受影响的个人带来相当大的困难，并给社会带来重大的经济负担。将这些组织恢复到原始强度的能力与治疗组织中形成的胶原蛋白基质的质量密切相关。因此，人们对构成肌腱中胶原纤维的蛋白质和调节纤维生长的细胞外蛋白质给予了相当多的关注。然而，我们对这些过程的更高级别的监管一无所知。该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原纤维生长的转录网络。确定这一过程中的关键监管参与者可能会为增强肌腱和韧带损伤或置换的临床结果开辟新途径。