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: 8556201
• 负责人: Kenan Rifat Omurtag
• 金额: $ 4.03万
• 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 2013-07-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8556201
• 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; public health relevance; 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. ! !

说明（由申请人提供）：二恶英是一类毒性很高、分布广泛的环境危害物，与男性生殖细胞功能失常有关，甚至与父亲接触二恶英有关的不良妊娠结果有关。其中许多影响需要几年时间才能显现出来。研究人员试图在细胞和分子水平上描述二恶英结合的毒性，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性配子的作用机制是否涉及芳烃受体（AhR）和葡萄糖转运之间的通信。此外，我们试图确定二恶英暴露是否会影响精子发生不同阶段的生殖细胞和干细胞中的基因表达。这些变化可能直到相对于暴露更晚才显现，因此可以解释父亲对后代和妊娠结局的影响。以前的研究表明，AhR受体，也被称为“二恶英受体”，可能在身体其他各种组织的上皮细胞中降低葡萄糖利用率方面发挥作用。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起着重要的作用，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。我们实验室先前的研究已经显示了葡萄糖稳态破坏对小鼠精子发生、精子活力和受精能力的几种功能性抑制。此外，我们已经建立了一个激光显微切割睾丸切片的协议，并成功地验证了我们的技术。我们推测，二恶英暴露破坏精子发生通过激活AhR受体和随后的破坏葡萄糖转运蛋白（GLUT）亚型不利地影响基本的细胞功能和发展。我们提出以下具体目标来研究这一假设。 具体目的1：睾丸中哪些细胞类型（体细胞和生精生殖细胞阶段）表达芳烃受体？ 具体目标2.睾丸中GLUT 8、GLUT 9a和GLUT 9 b的蛋白质和mRNA表达是否受到TCDD暴露的影响？传送器的位置改变了吗？ 特定目的3：睾丸中AhR表达的缺乏是否消除了TCDD的作用？AhR缺乏会影响睾丸中葡萄糖转运蛋白的表达吗？! 提出这一建议的理由是，确定毒性损伤男性生殖细胞的机制将导致更好地了解环境毒素在父亲传播畸形和男性不育症中的作用。如果成功地完成这些目标，我们将阐明一个新的主要下游效应的激活芳烃受体。外源性激活的AhR的二恶英，导致减少葡萄糖利用睾丸细胞之间将突出一个可能的作用机制，可以进一步了解某些生殖结果，已链接到父亲的有毒暴露。! !