Identifying gene and regulatory networks underlying postnatal tendon cell growth

总结 肌腱连接并传递肌肉和骨骼之间的力。他们的 发展，成长和成熟必须与他们的发展相协调。 邻近组织在成年人中，肌腱非常容易受伤，并且具有缓慢和有限的功能。 治愈潜力通过更好地了解调节肌腱的机制， 生物学，我们将能够改善肌腱损伤再生治疗的设计 和疾病出生后肌腱细胞的生长和成熟目前知之甚少， 过程许多研究都集中在细胞外基质中发生的变化， 胶原原纤维的尺寸增大。然而，很少有研究检查了分子变化， 在全基因组水平上放置在出生后阶段的肌腱细胞中。在这次合作中 我们将应用独特的新技术分离肌腱特异性细胞群 并阐明与特定的产后疾病相关的基因网络和调控区域， 发展转型。这种转变是通过我们未发表的细胞研究确定的。 出生后和成年期的更替率。我们发现，有一个特定的阶段， 其中细胞从高循环速率转变为低循环速率，类似于低更新的成年状态。 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， 过渡阶段与先前研究中报道的再生潜力的改变相关。 基于此，我们将对出生后阶段的肌腱细胞进行RNA测序以鉴定转录本 其在活动和低循环状态之间被差分调节。候选人将被 通过小鼠肌腱组织中的基因表达分析验证。第二，我们将使用 ATAC-seq用于鉴定高细胞和低细胞期间调控控制的全基因组变化 周转期。将使用斑马鱼测试调节区域，以鉴定增强子， 肌腱组织中的活性。总之，这些目标将揭示基因表达和调控 当腱细胞从高循环期过渡到低循环期时， 在肌腱细胞生长和成熟的过程中。这些发现将增强我们对 肌腱调节的分子水平，并将提供新的候选途径，以测试在 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 This transition was identified through our unpublished studies on cell turnover rates during postnatal and adult periods.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.