THE EFFECT OF DIOXINS ON GLUCOSE HOMEOSTASIS IN MURINE TESTES

二恶英对小鼠睾丸葡萄糖稳态的影响

• 批准号: 8202413
• 负责人: Kenan Rifat Omurtag
• 金额: $ 6.13万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8202413
• 关键词: Address; Affect; Aryl Hydrocarbon Receptor; Binding; Cell physiology; Cells; Communication; Data; Dioxins; Embryo; Environment; Environmental Exposure; Environmental Hazards; Epithelial Cells; Exposure to; Family; Fertilization; Gene Expression; Germ Cells; Glucose; Glucose Transporter; Glycolysis; Infertility; Injury; Kinetics; Lasers; Lead; Link; Location; Male Infertility; Mediating; Metabolic; Microdissection; Mitochondria; Molecular; Mus; Oocytes; Outcome; Oxidative Phosphorylation; Oxygen; Paternal Exposure; Pentosephosphate Pathway; Play; Pregnancy Outcome; Process; Production; Protein Isoforms; Protocols documentation; Receptor Activation; Relative (related person); Research; Research Personnel; Role; Signal Transduction; Signaling Protein; Sperm Count Procedure; Sperm Motility; Spermatogenesis; Staging; Stem cells; Substrate Specificity; Techniques; Testing; Testis; Tetrachlorodibenzodioxin; Tissues; Toxic Environmental Substances; Toxic effect; Toxicant exposure; blood glucose regulation; cell type; cellular development; glucose transport; mRNA Expression; male; malformation; member; novel; offspring; protein expression; receptor; receptor expression; reproductive; sperm cell; sperm function; transmission process

DESCRIPTION (provided by applicant): Dioxins represent a class of highly toxic and widely dispersed environmental hazards that have been implicated in aberrations in male reproductive cell function and even adverse pregnancy outcomes associated with paternal exposure. Many of these effects take several years to manifest. Investigators have attempted to characterize the toxicity of dioxin binding at a cellular and molecular level, but to date the mechanism remains incompletely understood. The objective of this study is to determine whether the mechanism of action of dioxin exposure on male gametes involves communication between the aryl hydrocarbon receptor (AhR) and glucose transport. In addition we seek to determine if dioxin exposure affects gene expression in the germ cells and perhaps stem cells at different stages of spermatogenesis. These changes may not manifest until much later relative to exposure and thus may explain the paternal effects on offspring and pregnancy outcome. Previous studies suggest that the AhR receptor, also known as the "dioxin receptor," may play a role in decreased glucose utilization in epithelial cells in various other tissues of the body. Our preliminary data show that glucose transporters play a significant role in the testes and on spermatogenesis and that certain cell signaling proteins/receptors play a role in modulating glucose homeostasis in these germ cells at the various stages of spermatogenesis. Previous study in our lab has shown several functional detriments to spermatogenesis, sperm motility, and fertilization capability in mice affected with disruptions in glucose homeostasis. Moreover we have established a Laser Microdissection protocol for testis sections and have successful validate our techniques. We hypothesize that dioxin exposure disrupts spermatogenesis through activation of the AhR receptor and subsequent disruption of glucose transporter (GLUT) isoforms adversely affects essential cellular function and development. We address the following specific aims to investigate this hypothesis. SPECIFIC AIM 1: Which cell types, somatic and spermatogenic germ cell stages, in the testes express the Arylhydrocarbon Receptor? SPECIFIC AIM 2. Are protein and mRNA expression of GLUT8, GLUT9a and GLUT9b in the testes affected by exposure to TCDD? Is the location of the transporters altered? SPECIFIC AIM 3: Does a lack of AhR expression eliminate the effect of TCDD in the testes? Does AhR deficiency affect glucose transporter expression in the testes? ! The rationale for this proposal is that identifying the mechanism of toxic injury to male germ cells will lead to a better understanding the role of environmental toxins in paternal transmission of malformations and male infertility. If successful in completing these aims, we will have elucidated a novel major downstream effect of activation of the Aryl hydrocarbon receptor. Exogenous activation of the AhR by dioxins, resulting in decrease glucose utilization among cells in the testes would highlight a likely mechanism of action that could further our understanding of certain reproductive outcomes that have been linked to paternal toxic exposures. ! ! PUBLIC HEALTH RELEVANCE: Dioxins represent a class of highly toxic and widely dispersed environmental hazards that are the unintentional byproducts of many industrial processes. Sperm cell production is known to be adversely affected by dioxin exposure, perhaps contributing to low sperm counts and poor function of the sperm cells. This research will help us better understand how such environmental exposures may affect the male reproductive tract.

描述（由申请人提供）：二恶英代表一类剧毒且广泛分布的环境危害，与男性生殖细胞功能异常甚至与父亲接触相关的不良妊娠结局有关。其中许多影响需要数年时间才能显现。研究人员试图在细胞和分子水平上表征二恶英结合的毒性，但迄今为止其机制仍不完全清楚。本研究的目的是确定二恶英暴露对雄配子的作用机制是否涉及芳基碳氢化合物受体 (AhR) 和葡萄糖转运之间的通讯。此外，我们还试图确定二恶英暴露是否会影响生殖细胞以及精子发生不同阶段的干细胞的基因表达。这些变化可能要等到相对于暴露很晚的时候才会显现出来，因此可以解释父亲对后代和妊娠结局的影响。先前的研究表明，AhR 受体（也称为“二恶英受体”）可能在身体其他各种组织的上皮细胞葡萄糖利用率降低中发挥作用。我们的初步数据表明，葡萄糖转运蛋白在睾丸和精子发生中发挥重要作用，并且某些细胞信号蛋白/受体在精子发生的各个阶段调节这些生殖细胞中的葡萄糖稳态中发挥作用。我们实验室之前的研究表明，受葡萄糖稳态破坏影响的小鼠的精子发生、精子活力和受精能力会受到多种功能损害。此外，我们还建立了睾丸切片的激光显微切割方案，并成功验证了我们的技术。我们假设二恶英暴露通过激活 AhR 受体来扰乱精子发生，并随后破坏葡萄糖转运蛋白 (GLUT) 亚型，从而对基本细胞功能和发育产生不利影响。我们提出以下具体目标来研究这一假设。 具体目标 1：睾丸中哪些细胞类型（体细胞和生精生殖细胞阶段）表达芳基烃受体？ 具体目标 2. 睾丸中 GLUT8、GLUT9a 和 GLUT9b 的蛋白质和 mRNA 表达是否受到 TCDD 暴露的影响？运输机的位置是否改变？ 具体目标 3：缺乏 AhR 表达是否会消除 TCDD 对睾丸的影响？ AhR 缺乏会影响睾丸中葡萄糖转运蛋白的表达吗？ ！ 该提案的基本原理是，确定男性生殖细胞毒性损伤的机制将有助于更好地了解环境毒素在畸形和男性不育的父系传播中的作用。如果成功完成这些目标，我们将阐明芳基烃受体激活的新的主要下游效应。二恶英对 AhR 的外源激活，导致睾丸细胞中葡萄糖的利用率降低，这将凸显出一种可能的作用机制，可以进一步我们对与父亲毒性暴露相关的某些生殖结果的理解。 ！ ！ 公众健康相关性：二恶英是一类剧毒且分布广泛的环境危害物，是许多工业过程中无意产生的副产品。已知精子细胞的产生会受到二恶英暴露的不利影响，可能导致精子数量低和精子细胞功能差。这项研究将帮助我们更好地了解此类环境暴露如何影响男性生殖道。