EXAMINATION OF STRESS RESPONSE GENES FOLLOWING MEHP-INDUCED TESTICULAR INJURY

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。邻苯二甲酸盐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普遍存在的。在医学上特别值得关注的是，胎儿、早产儿和婴儿因接触生物医学设备和摄入受污染的食物而接触邻苯二甲酸盐。在啮齿类动物模型中，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、肛门生殖器距离缩短、隐睾症、不孕症和精管形成异常。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，也是一种已知的睾丸细胞毒物。尽管有大量的研究，青春期周围的小鼠模型和控制邻苯二甲酸盐损伤的分子途径是缺乏的。这个试点项目的目标是确定参与分子和细胞信号通路介导睾丸细胞死亡后邻苯二甲酸盐暴露的基因。我们的初步数据表明，体内暴露于MEHP的Akt1缺陷小鼠的睾丸对生殖细胞凋亡具有惊人的敏感性，这证明了Akt1在青春期周围生殖细胞存活中的关键作用，并将该小鼠作为青春期周围暴露于邻苯二甲酸盐损伤的模型。利用基因组微阵列技术，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，以确定与Akt1介导的细胞存活途径相关的基因。其次，我们将通过检测暴露于MEHP后的Akt1/p53双缺陷小鼠的睾丸基因表达，确定p53（一个与MEHP诱导的睾丸损伤抗性有关的基因）是否调节Akt1介导的应答。相关性：新基因的鉴定将导致临床生物标志物的发展，这些标志物将识别暴露于邻苯二甲酸盐毒性水平的新生儿。这项研究的最终目标是确定可以在临床环境中控制的发育途径，以尽量减少或防止邻苯二甲酸盐的毒性暴露。

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.