Molecular Mechanisms of Leydig Cell Regeneration

在许多成人组织中，由于正常磨损而失去的细胞被干细胞的活性所取代。作为回应 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。损伤组织 可以通过激活干细胞或从祖细胞再生，与干细胞不同， 不能进行非对称分裂和自我更新。细胞发生了戏剧性的变化 再生被认为是由于组织微环境或生态位中信号的改变而产生的，但 调控再生的机制在很大程度上是未知的。损伤后再生的一个经典模型是 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。 关键的躯体支持细胞包括间质细胞，这是男性产生雄激素的主要细胞，它是 是男性健康和生育所必需的。虽然间质细胞是一种静止的细胞类型，并不被认为是分裂的 在正常情况下，它们会被乙烷二甲基磺酸盐(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在睾丸中。间质细胞再生及其机制研究进展 它们产生的祖先仍然鲜为人知，部分原因是缺乏遗传工具 在老鼠身上可用。体外研究已经暗示了可能识别间质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。 间质细胞再生。小鼠的遗传学使我们有可能询问 通过使用可诱导的遗传谱系追踪系统进行再生。在初步数据中，体细胞的一个子集 小鼠睾丸间质细胞消融后可分化为新的间质细胞。我们将继续使用这种模式来 确定祖细胞的身份以及该细胞类型是否具有自我更新能力。我们还将 利用sc-rna测序，在再生前、中、中、 在再生之后。与信号和间质细胞发育有关的候选基因 在再生细胞中差异表达的基因将在再生过程中使用小分子 分子途径抑制物和可用的遗传工具。虽然小分子是一种容易获得的方式 关于是否涉及信号通路的粗略信息，sc-rna测序将准确地阐明 哪些细胞产生启动祖细胞反应的信号。确定细胞和分子 间质细胞再生的机制将有助于理解成人组织 体内再生对男性生育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.