EXAMINATION OF STRESS RESPONSE GENES FOLLOWING MEHP-INDUCED TESTICULAR INJURY

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。邻苯二甲酸酯是一组使塑料具有延展性的化学物质。人类接触邻苯二甲酸盐是无处不在的。特别值得关注的医学问题是胎儿、早产儿和婴儿因生物医学设备和摄入受污染的食物而暴露于邻苯二甲酸盐。在啮齿动物模型中，邻苯二甲酸盐暴露会导致多种生殖异常，包括睾酮合成减少、肛门距离缩短、隐睾症、不育症和生精小管形成异常。邻苯二甲酸二(2-乙基己基)酯(DEHP)已被证明会损害新生动物的雄性和雌性生殖系统。MEHP是增塑剂DEHP的活性代谢物，是一种已知的睾丸细胞毒物。尽管有大量的研究，但缺乏青春期小鼠模型和控制邻苯二甲酸盐损伤的分子途径。这个试点项目的目标是确定在邻苯二甲酸盐暴露后介导睾丸细胞死亡的分子和细胞信号通路中涉及的基因。我们的初步数据表明，在体内暴露于MEHP的Akt1基因缺陷小鼠的睾丸对生殖细胞凋亡具有显著的敏感性，这表明Akt1在青春期周围生殖细胞的生存中发挥了关键作用，并将该小鼠用作青春期周围邻苯二甲酸盐损伤的模型。利用基因组芯片技术，我们将首先检测暴露于MEHP的Akt1野生型和Akt1缺陷小鼠的睾丸基因表达，以确定参与Akt1介导的细胞生存途径的基因。其次，我们将通过检测MEHP暴露后Akt1/P53双缺陷小鼠的睾丸基因表达来确定参与抵抗MEHP诱导的睾丸损伤的基因P53是否调节Akt1介导的反应。相关性：新基因的识别将导致临床生物标记物的开发，这些标记物将识别暴露在邻苯二甲酸盐中毒水平下的新生儿。这项研究的最终目标是确定可以在临床环境中操纵的发育途径，以最大限度地减少或防止邻苯二甲酸酯的毒性暴露。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Phthalates are a group of chemicals which give plastics their malleability. Human exposure to phthalates is ubiquitious. Of particular medical concern, is the exposure of fetuses, preterm infants, and babies to phthalates from exposures resulting from biomedical devices and through ingestion of contaminated foods. In rodent models, phthalate exposure leads to a variety of reproductive abnormalities including decreased testosterone synthesis, reduced anogenital distance, cryptorchidism, infertility, and aberrant seminiferous tubule formation. Di (2-ethylhexyl) phthalate (DEHP) has been shown to damage male and female reproductive systems in newborn animals. MEHP is the active metabolite of the plasticizer, DEHP, and a known testicular cell toxicant. In spite of numerous studies, peri-pubertal mouse models and the molecular pathways which control phthalate injury are lacking. The goal of this pilot project is to identify genes involved in the molecular and cellular signaling pathways which mediate testicular cell death following phthalate exposure. Our preliminary data indicate a striking sensitivity to germ cell apoptosis in the testes of Akt1-deficient mice exposed to MEHP in vivo, demonstrating both a critical role for Akt1 in the survival of peri-pubertal germ cells and use of this mouse as a model for peri-pubertal exposure to phthalate injury. Utilizing genomic microarray technologies, we will first examine testis gene expression in Akt1 wild type and Akt1 deficient mice exposed to MEHP to identify genes involved in an Akt1-mediated cell survival pathway. Second, we will determine if p53, a gene implicated in resistance to MEHP-induced testis injury, modulates the Akt1-mediated response by examination of testis gene expression in Akt1/p53 double deficient mice following MEHP exposure. Relevance: The identification of novel genes will lead to the development of clinical biomarkers which will identify neonates exposed to toxic levels of phthalates. The ultimate goal of the research is to identify developmental pathways which can be manipulated in a clinical setting to minimize or prevent toxic exposure to phthalates.