Molecular Mechanisms of Leydig Cell Regeneration

在许多成人组织中，由于正常磨损而丢失的细胞被干细胞的活性所取代。响应 然而，对于损伤，细胞可以使用完全不同的策略来修复和再生组织。受伤组织 可以通过激活干细胞或祖细胞再生，与干细胞不同， 不能不对称分裂和自我更新。在这一过程中发生的细胞的巨大变化 再生被认为是由组织微环境或生态位中改变的信号传导引起的，但是， 调节再生的机制在很大程度上是未知的。损伤后再生的经典模型是 成年大鼠睾丸在睾丸中，体细胞创造了一个有助于生殖细胞生态位的微环境。 关键的体细胞支持细胞包括Leydig细胞，这是雄性中主要的雄激素产生细胞， 男性健康和生育能力所必需的。虽然间质细胞是一种静止细胞类型， 在正常条件下，它们被乙烷二甲烷磺酸盐（EDS）化学烧蚀。几个星期 在化学消融后，新的间质细胞重新填充睾丸。睾丸间质细胞再生的机制及 它们的祖先仍然知之甚少，部分原因是缺乏遗传工具 在大鼠中可用。体外研究暗示了可能识别Leydig细胞祖细胞的候选标记 再生本项目的目标是确定细胞机制和分子机制， Leydig细胞再生小鼠遗传学使得研究细胞机制成为可能， 通过使用诱导型遗传谱系追踪系统再生。在初步数据中，一个体细胞亚群 小鼠睾丸间质细胞在消融后追踪到新的Leydig细胞。我们将继续使用这种模式， 确定祖细胞的身份和这种细胞类型是否自我更新。我们还将 确定驱动再生的分子机制，使用sc-RNA测序之前，期间， 再生后。参与信号传导和Leydig细胞发育的候选基因， 在再生细胞中的差异表达将使用小的 分子途径抑制剂和可用的遗传工具。虽然小分子是一种获得 关于信号通路是否参与的粗略信息，sc-RNA测序将精确地阐明 这些细胞产生启动祖细胞反应的信号。确定细胞和分子 Leydig细胞再生的机制将大大有助于了解成年组织 体内再生，对男性生育力和健康有更广泛的影响。

Cells lost to normal wear and tear in many adult tissues are replaced with the activity of stem cells. In response to injury, however, cells can use entirely different strategies to repair and regenerate tissues. Injured tissues can be regenerated through the activation of stem cells or from progenitor cells that, unlike stem cells, are incapable of asymmetric division and self-renewal. The dramatic cellular changes that occur during regeneration are thought to arise from altered signaling in the tissue microenvironment, or niche, but the mechanisms regulating regeneration are largely unknown. A classical model of regeneration after injury is the adult rat testis. In the testis, somatic cells create a microenvironment that contributes to the germ cell niche. Critical somatic support cells include Leydig cells, the major androgen producing cells in males, which are required for male health and fertility. Although Leydig cells are a quiescent cell type, and not thought to divide under normal conditions, they are chemically ablated by ethane dimethane sulfonate (EDS). Several weeks after chemical ablation, new Leydig cells repopulate the testis. The mechanism of Leydig cell regeneration and the progenitors from which they arise remain poorly understood, partially due to the lack of genetic tools available in rats. In vitro work has hinted at candidate markers that may identify progenitors of Leydig cell regeneration. The goal of this project is to determine the cellular mechanism and molecular mechanism of Leydig cell regeneration. Mouse genetics make it possible to interrogate the cellular mechanism of regeneration by use of an inducible genetic lineage tracing system. In preliminary data, a subset of somatic testis interstitial cells trace into new Leydig cells after ablation in mice. We will continue using this model to determine the both identity of the progenitor cells and whether this cell type is self-renewing. We will also determine the molecular mechanisms driving regeneration with the use of sc-RNA sequencing before, during, and after regeneration. Candidate genes implicated in signaling and Leydig cell development that are differentially expressed in regenerating cells will be tested for functional roles during regeneration using small molecule pathway inhibitors and available genetic tools. While small molecules are an accessible way to gain crude information about whether a signaling pathway is involved, sc-RNA sequencing will illuminate exactly which cells produce signals that initiate the progenitor response. Determining the cellular and molecular mechanisms of Leydig cell regeneration will significantly contribute to the understanding of adult tissue regeneration in vivo with broader implications for male fertility and health.