Impacts of Genetic and Environmental Factors on Reproductive Organ Development

遗传和环境因素对生殖器官发育的影响

• 批准号: 9550169
• 负责人: Hung Chang Yao
• 金额: $ 212.76万
• 依托单位: NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH SCIENCES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/9550169
• 关键词: Adult; Affect; Anatomy; Androgen Receptor; Androgens; Animals; Arsenic; Bisexual; Carcinogens; Cell Lineage; Cells; Chemicals; Decision Making; Development; Developmental Biology; Dose; Duct (organ) structure; Embryo; Embryology; Embryonic Development; Endocrine Disruptors; Endothelial Cells; Environmental Risk Factor; Erinaceidae; Estrogen Receptors; Estrogens; Exhibits; Exposure to; FOXL2 gene; Female; Fertility; Fetal Development; Fetus; Fibroblasts; Food; Genetic; Genome Stability; Germ Cells; Gonadal structure; Hormonal; Hormones; Human; Lead; Maintenance; Malignant Neoplasms; Mesenchymal; Mesenchyme; Mesonephric structure; Modeling; Molecular; Mus; Neurologic; Nuclear Orphan Receptor; Organ; Organ Model; Ovarian Follicle; Ovary; Pathway interactions; Pattern; Phenotype; Population; Primordium; Process; Production; Pseudohermaphroditism; Puberty; Regulation; Research; SF1; Secure; Signal Pathway; Signal Transduction; Signaling Molecule; Somatic Cell; Source; Stem cells; Steroid Receptors; Steroid biosynthesis; Steroids; Structure of mesonephric duct; Testis; Time; Tissues; Vagina; Water; cell type; drinking water; early onset; experience; experimental study; female reproductive system; fetal; genome wide methylation; granulosa cell; in utero; insight; interest; male; mouse model; novel; organ growth; pregnant; premature; prenatal exposure; progenitor; progenitor system; reproductive; reproductive development; reproductive organ; reproductive tract; sertoli cell; sex; steroid hormone; theca cell

1. Identify the sources of somatic cell lineages in the fetal gonads and investigate how they acquire their organ-specific identities Organs are composed of common cell types, such as fibroblasts and vasculature endothelial cells, and specialized cell types that define the unique functions of the organs. These specialized cells are thought to originate from organ-specific progenitor cells and acquire their identity during embryogenesis. My lab is using the gonads as a model organ to study how progenitor cells make decision to differentiate into various tissue-specific cell types. Testis and ovary derive from a common primordium during embryogenesis. The primordium, through cell automatous fate determination and intercellular signaling, gives rise to cell types unique to testis (Sertoli, Leydig, and peritubular myoid cells) and ovary (granulosa, theca, and unknown somatic stem cells). Using genetic lineage tracing mouse models, we first characterize the progenitor cells in the primordium and study their sex specification process. For example in the fetal ovary, we discover for the first time the lineage transition of granulosa cells from progenitor state (Steroidogenic factor 1 or SF1 positive) to initial fate specification (FOXL2 positive). This lineage transition process is actively suppressed in the fetal testis by the TGF pathway, therefore allowing the progenitor cells to differentiate into FOXL2-negative Sertoli cells. We have also discovered that theca cells, a mesenchymal cell type supporting development of the ovarian follicles, consist of at least two populations that come from complete different origins. These findings provide a paradigm shift on the origin of the cell types in the gonads as well as the regulation of gonadal formation. It is worth noting that the progenitor cells in the gonads are positive for various steroid receptors such as estrogen and androgen receptors, suggesting that these progenitor cells could be targets of endocrine disruptors. 2. Define the cellular and molecular processes that lead to sexually dimorphic establishment of the reproductive tracts Before sexual differentiation occurs, embryos are anatomically bisexual as they possess both male and female reproductive tracts. These two tracts derive from two separate progenitor systems in the fetal mesonephros: Wolffian duct for the male tract and Mllerian duct for the female tract. In the male embryos, Wolffian ducts are maintained by testis-derived androgens while Mllerian duct undergo regression induced by anti-Mllerian hormone, also a product of testes. Female embryos, which do not produce androgens or anti-Mllerian hormone (AMH), experience the opposite where Mllerian ducts are maintained and Wolffian ducts undergo regression. In search of novel regulators in this process, we discovered the presence of orphan nuclear receptor COUPTFII in the mesenchyme of the mesonephros. Inactivation of COUPTFII specifically in the mesonephric mesenchyme leads to maintenance of both Wolffian and Mllerian ducts in the male and female mouse embryos, a typical case of pseudohermaphroditism. The affected embryos still have sex-specific production of hormones (androgen and AMH), indicating that hormonal abnormality is not responsible for the pseudohermaphroditic phenotypes of the reproductive tracts. Instead, COUPTFII in the mesenchyme of the mesonephros appears to be a molecular switch that controls the decision-making process of the identity of reproductive tract progenitors. This novel finding provides new mechanistic insights into the dimorphic establishment of reproductive tract. Ongoing experiments are to identify the upstream and downstream regulators of COUPTFII in this process. 3. Investigate the effects of in utero exposure to endocrine disruptors on the development of fetal reproductive organs and its lingering impacts on fertility in adulthood Formation of fetal reproductive organs relies on an intricate interaction between steroid hormones and signaling molecules, therefore making this process a prime target of endocrine disruptors. Chemicals or compounds that mimic or interfere with the action of steroid hormone and signaling molecules are known to have detrimental impacts on fetal reproductive organ formation and long-term impacts on fertility when the affected animals reach adulthood. Arsenic, a human carcinogen found in underground water and food products, has been shown to affect the Hedgehog pathway, one of the signaling pathways important for the formation of reproductive organs. Exposure of moues embryos to arsenic leads to cancer development in the ovary and reproductive tracts, organs where the Hedgehog pathway is functional. To investigate whether arsenic exposure targets the Hedgehog pathway in the fetal gonads and reproductive tract, we expose pregnant mice with various doses of inorganic arsenic in the drinking water. We found a dose-dependent and organ-specific effect of arsenic exposure on the Hh pathway: arsenic activates the Hedgehog pathway in the ovary whereas decrease its activity in the fetal testis. When some of the exposed female fetuses are allowed to develop to adulthood, they exhibit precocious onset of puberty (vaginal opening) compared to the control littermate. The Hedgehog pathway is known to control steroidogenesis in the ovary and testis. We therefore hypothesize that altered Hedgehog activity by in utero arsenic exposure could contribute to premature steroid (i.e. estrogen) production and consequent early onset of puberty in the affected female. Our findings are the first to demonstrate a potential impact of arsenic exposure on female reproductive systems. We are collaborating with Jean Harry and Mike Walkkes at NTP to study the neurological impacts of arsenic on these animals.

1.确定胎儿性腺中体细胞谱系的来源，并调查它们如何获得器官特异性身份 器官由常见的细胞类型组成，如成纤维细胞和血管内皮细胞，以及定义器官独特功能的特殊细胞类型。这些特化细胞被认为起源于器官特异性祖细胞，并在胚胎发育过程中获得身份。我的实验室正在使用性腺作为模型器官来研究祖细胞如何决定分化为各种组织特异性细胞类型。在胚胎发育过程中，睾丸和卵巢起源于共同的原基。原基通过细胞自动决定命运和细胞间信号传递，产生睾丸(支持细胞、间质细胞和管周肌样细胞)和卵巢(颗粒细胞、膜细胞和未知的体细胞)所特有的细胞类型。利用遗传谱系追踪的小鼠模型，我们首先对原基中的祖细胞进行了表征，并研究了它们的性别指定过程。例如，在胎儿卵巢中，我们首次发现颗粒细胞从祖细胞状态(类固醇生成因子1或SF1阳性)到最初的命运指定(FOXL2阳性)的谱系转变。这种谱系转换过程在胎儿睾丸中被转化生长因子途径主动抑制，因此允许祖细胞分化为FOXL2阴性的Sertoli细胞。我们还发现，卵泡膜细胞是一种支持卵巢卵泡发育的间充质细胞类型，由至少两个来自完全不同来源的群体组成。这些发现为性腺细胞类型的起源以及性腺形成的调节提供了范式转变。值得注意的是，性腺中的前体细胞对雌激素和雄激素受体等多种类固醇受体呈阳性反应，表明这些前体细胞可能是内分泌干扰物的靶标。 2.确定导致生殖道性别二态建立的细胞和分子过程 在性别分化发生之前，胚胎在解剖学上是双性的，因为它们同时拥有男性和女性生殖道。这两个束起源于胎儿中肾的两个不同的祖细胞系统：男性的Wolffian管和女性的Milerian管。在雄性胚胎中，Wolffian管由睾丸来源的雄激素维持，而Mllerian管经历抗Mllerian激素诱导的退化，抗Mllerian激素也是睾丸的产物。雌性胚胎不产生雄激素或抗米勒氏激素(AMH)，在米勒管保持和沃尔夫管退化的情况下，经历相反的情况。为了在这个过程中寻找新的调节因子，我们发现在中肾间充质中存在孤儿核受体COUPTFII。COUPTFII在中肾间充质中的失活导致雄性和雌性小鼠胚胎中Wolffian和Mllerian导管的维持，这是典型的假两性畸形。受影响的胚胎仍有性别特异性激素(雄激素和AMH)的产生，表明激素异常不是生殖道假两性表型的原因。相反，中肾间充质中的COUPTFII似乎是一个分子开关，控制着生殖道祖细胞身份的决策过程。这一新的发现为生殖道的二相性建立提供了新的机制见解。正在进行的实验是为了确定COUPTFII在这一过程中的上游和下游调控因子。 3.研究宫内暴露于内分泌干扰物对胎儿生殖器官发育的影响及其对成年后生育的挥之不去的影响 胎儿生殖器官的形成依赖于类固醇激素和信号分子之间复杂的相互作用，因此使这一过程成为内分泌干扰物的主要靶点。已知，模仿或干扰类固醇激素和信号分子的作用的化学品或化合物对胎儿生殖器官的形成有不利影响，并在受影响的动物成年后对生育能力产生长期影响。砷是一种在地下水和食品中发现的人类致癌物质，已被证明会影响Hedgehog途径，这是生殖器官形成的重要信号途径之一。暴露在砷中的小鼠胚胎会导致卵巢和生殖道的癌症发展，而这些器官是刺猬途径的功能所在。为了研究砷暴露是否针对胎儿性腺和生殖道中的刺猬途径，我们将怀孕小鼠暴露在饮用水中不同剂量的无机砷中。我们发现砷暴露对HH途径具有剂量依赖性和器官特异性的影响：砷激活卵巢中的Hedgehog途径，而降低其在胎儿睾丸中的活性。当一些暴露的女性胎儿被允许发育到成年时，与对照组相比，她们表现出性早熟(阴道开放)。已知Hedgehog途径控制卵巢和睾丸中类固醇的生成。因此，我们推测，子宫内砷暴露改变刺猬的活动可能会导致类固醇(即雌激素)的过早产生，从而导致受影响女性青春期的提前开始。我们的发现首次证明了砷暴露对女性生殖系统的潜在影响。我们正在与NTP的Jean Harry和Mike Walkkes合作，研究砷对这些动物的神经学影响。