The role of retinoid exposure in specification of the foundational SSC pool

类维生素A暴露在基础SSC池规范中的作用

• 批准号: 9884801
• 负责人: Christopher Bennett Geyer
• 金额: $ 30.05万
• 依托单位: EAST CAROLINA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-03-26 至 2022-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9884801
• 关键词: Address; Adult; Affect; Agonist; Biological Assay; Catabolism; Cells; Characteristics; Data; Defect; Development; Ensure; Environment; Exhibits; Fertility; Foundations; Gene Expression; Germ Cells; Gold; Heterogeneity; Human; In Vitro; Infertility; Lead; Link; Longevity; Malignant neoplasm of testis; Measures; Methods; Molecular; Mus; Neonatal; Population; Production; Proliferating; Retinoic Acid Receptor; Retinoids; Role; Signal Transduction; Somatic Cell; Specific qualifier value; Spermatogenesis; Spermatogonia; Stem cell transplant; Testing; Testis; Transgenic Mice; Tretinoin; Undifferentiated; base; design; enzyme activity; in vivo; inhibitor/antagonist; insight; male; molecular subtypes; neuronal cell body; postnatal; postnatal development; prevent; progenitor; reproductive; response; segregation; self-renewal; sertoli cell; sperm cell; stem cell fate; stem cell population; stem cells

PROJECT SUMMARY/ABSTRACT Spermatogenesis begins in the neonatal mouse testis with the segregation of prospermatogonia into distinct undifferentiated and differentiating populations. A proportion of undifferentiated spermatogonia retain stem cell potential (as foundational spermatogonial stem cells, or SSCs), and the remainder becomes progenitor spermatogonia that proliferate and differentiate in response to retinoic acid (RA). This initial fate decision is critical, as imbalances cause spermatogenic defects that can lead to human testicular cancer or infertility. It is currently unknown how spermatogonial fate decisions are regulated. We have recently made the exciting discovery that neonatal male germ cells differ in their responsiveness to RA both in vivo and in vitro (in the absence of the niche environment). As early as postnatal day (P) 1, we can identify two distinct subpopulations of prospermatogonia: 1 – those that cannot respond to RA (‘RA-non-responsive’) either in vitro or in vivo, and 2 – those that can respond but do not yet in vivo (‘RA-responsive’). The objective of this proposal is to determine whether the foundational SSC pool forms from prospermatogonia that are intrinsically preprogrammed (predetermination) or from those that happen to occupy a limited number of stem cell niches (selection). Our data strongly suggest that some prospermatogonia are predetermined to remain undifferentiated and become SSCs, and that this fate is manifest by an inability to respond to the proliferation and differentiation signal provided by RA. In the proposed aims, we will explore whether this RA insensitivity is intrinsic (germ cell autonomous) or determined by somatic cells (germ cell non-autonomous), define when during postnatal development differential RA responsiveness appears, and determine whether the foundational SSC pool is formed solely from these RA-insensitive germ cells. In Aim 1, we will assess gene expression heterogeneity associated with neonatal germ cell RA responsiveness. Heterogeneous expression of genes involving RA responsiveness by either the germline or soma could explain which compartment dictates the fate of SSC precursors. In Aim 2, we will define the roles of RA reception and catabolism in RA responsiveness. We predict that RA insensitivity is intrinsically preprogrammed, long lasting, and defines the foundational SSC population. In Aim 3, we will determine whether RA-insensitive prospermatogonia preferentially give rise to foundational SSCs. We will modulate RA levels in vivo and examine the subsequent effect on formation of the foundational SSC pool. Together, the results of these aims will define how RA responsiveness contributes to formation of the foundational SSC pool in the neonatal testis.

项目摘要/摘要 精子发生始于新生小鼠睾丸，随着繁荣的隔离为 独特的未分化和分化的人群。一部分未分化的精子 保留干细胞电位（作为基础精子干细胞或SSC），其余 成为祖细胞的祖细胞多症，响应视黄酸（RA）增殖和分化。 最初的命运决定至关重要，因为失衡会导致精子缺陷，这可能导致人类 有检验的癌症或不育。目前尚不清楚精子命运的决定如何受到调节。 我们最近已经提出了令人兴奋的发现，即新生儿男性生殖细胞在其上有所不同 对体内和体外RA的反应性（在没有利基环境的情况下）。最早 产后日（P）1，我们可以识别出繁荣的两个不同的亚群：1 - 在体外或体内都无法对RA（“ Ra-non-responsive”）做出反应，以及2 - 那些可以回应的人 但是请勿在体内（“ ra响应式”）。该提议的目的是确定是否 来自Prospermatogonia的基础SSC池形式本质上是预编程 （预定）或碰巧占据有限数量的干细胞壁ni（选择）的人。 我们的数据强烈表明，一些繁荣的人是预先确定的，以保持未分化 并成为SSC，并且这种命运是由于无法应对扩散而表现出来的 RA提供的分化信号。在拟议的目标中，我们将探讨这种不敏感的 是固有的（生殖细胞自主）或由体细胞（生殖细胞非自主）确定的，定义 当出现产后开发期间出现差异响应能力时，并确定是否 基础SSC池仅由这些RA对不敏感的生殖细胞形成。在AIM 1中，我们将 评估与新生儿生殖细胞RA反应性相关的基因表达异质性。 涉及种系或soma涉及RA反应性的基因的异质表达可以 说明哪个隔室决定了SSC前体的命运。在AIM 2中，我们将定义RA的角色 RA反应性中的接收和分解代谢。我们预测RA不敏感性是本质上的 预编程，持久并定义了基础SSC人群。在AIM 3中，我们将确定 RA对RA不敏感的Prospermatogonia是否优先引起基础SSC。我们将 调节体内RA水平，并检查后来对基础SSC形成的影响 水池。这些目标的结果共同定义了RA响应能力如何有助于形成 新生儿睾丸中的基础SSC池。