Identifying gene and regulatory networks underlying postnatal tendon cell growth

摘要 肌腱连接并在肌肉和骨骼之间传递力量。他们的 发展、成长和成熟必须与他们的发展、成长和成熟相协调 邻近的组织。在成年人中，肌腱很容易受伤，而且速度慢且有限。 治愈的潜力。通过更好地了解肌腱的调节机制 生物学我们将能够改进肌腱损伤的基于再生的疗法的设计 和疾病。出生后肌腱细胞的生长和成熟目前还知之甚少 进程。许多研究都集中在细胞外基质中发生的变化，如 胶原蛋白纤维会变大。然而，很少有研究研究这种分子变化 在全基因组水平上放置在出生后阶段的肌腱细胞中。在此协作环境中 提议，我们将应用独特和新颖的技术来分离肌腱特异性细胞群 并阐明与特定出生后相关的基因网络和调控区域 发展转型。这一转变是通过我们未发表的关于细胞的研究确定的 出生后和成人期的流动率。我们发现有一个特定的阶段 这些细胞从高循环率转变为低循环率，类似于成体的低周转状态。 在类似的阶段，我们也观察到基因表达水平的明显变化。有趣的是，这 过渡阶段与先前研究中报告的再生潜力的变化有关。 在此基础上，我们将对出生后阶段的肌腱细胞进行rna-seq来鉴定转录本。 在活跃和低循环状态之间受到不同的调节。候选人将是 通过小鼠肌腱组织的基因表达分析验证了该方法的有效性。第二，我们将使用 ATAC-SEQ识别高细胞和低细胞期间全基因组调控的变化 周转期。将使用斑马鱼对监管区域进行测试，以确定增强剂与 肌腱组织中的活性。总之，这些目标将揭示基因的表达和调控 肌腱细胞从高峰期过渡到低峰期时发生的景观变化 在肌腱细胞生长和成熟过程中。这些发现将加深我们对 肌腱在分子水平上的调节，将提供新的候选路径来测试 肌腱细胞生长、成熟和损伤修复的背景。

Summary Tendons connect and transfer the force between the muscles and the bone. Their development, growth, and maturation must take place in coordination with that of their neighboring tissues. In adults, tendons are highly prone to injury and have slow and limited healing potential. By gaining a better understanding of the mechanisms regulating tendon biology we will be able to improve the design of regenerative based therapies for tendon injury and disease. Postnatal tendon cell growth and maturation is currently a poorly understood process. Many studies have focused on the changes occurring in the extracellular matrix as the collagen fibrils grow in size. However, few studies have examined the molecular changes taking place in the tendon cells at postnatal stages on a genome-wide level. In this collaborative proposal, we will apply unique and novel techniques to isolate tendon-specific cell populations and elucidate the gene networks and regulatory regions associated with a specific postnatal developmental transition. This transition was identified through our unpublished studies on cell turnover rates during postnatal and adult periods. We found that there is a specific stage at which the cells shift from high to low cycling rates that resemble the adult state of low turnover. At similar stages, we also observe distinct changes in gene expression levels. Interestingly, this transition stage correlates with alterations in regenerative potential reported in previous studies. Based on this, we will perform RNA-seq of postnatal stage tendon cells to identify transcripts that are differentially regulated between active and low cycling states. Candidates will be validated through gene expression analysis in mouse tendon tissues. Second, we will use ATAC-seq to identify genome-wide changes in regulatory control during high and low cell turnover periods. Regulatory regions will be tested using the zebrafish to identify enhancers with activity in tendon tissues. Together, these aims will reveal the gene expression and regulatory landscape changes that occur as the tendon cells transition from high to low cycling periods during tendon cell growth and maturation. These discoveries will enhance our understanding of tendon regulation on a molecular level and would provide new candidate pathways to test in the context of tendon cell growth, maturation and injury repair.