Genetic Susceptibility to Developmental Benzo[a]pyrene Neurotoxicity

项目摘要。这是一项探索遗传易感性的初始奖项的续展申请。 苯并[a]芘(BaP)所致的发育神经毒性。BaP是一种典型的多环芳烃 在与交通相关的空气污染(陷阱)、野火、香烟烟雾和烧烤食品中发现。对人体的研究已经 产前和早期接触多环芳烃对认知和行为的不良影响 从儿童早期到青春期。广泛的动物研究强烈地表明芳香烃受体 (AHR)激动剂，包括多环芳烃在发育神经毒性中的作用。我们最初的研究使用的是带有基因的小鼠 AHR和受AHR调控的两种代谢酶：CYP1A1和CYP1A2的差异。三个都是 在人类群体中，感兴趣的基因各不相同，并与暴露于 陷阱。我们最初研究的数据有力地支持了我们的假设，即AHR途径在 介导BaP发育性神经毒性。Cyp1a1(-/-)和CYP1A2(-/-)基因敲除小鼠的 相同剂量苯并苯染毒对野生型小鼠学习记忆能力的影响 在怀孕和哺乳期间。有趣的是，我们还发现仅基于基因型的行为差异在 淘汰线。这一新发现表明，这两个基因在大脑发育或功能方面都有正常的作用。 人类和小鼠都有三个CYP1家族成员，因此我们未来的工作将探索其意义 并进一步探讨Cyp1a1和CyP1A2基因敲除中的神经毒性机制。目标1： 通过比较CYP1B1(+/+)野生型和CYP1B1(-/-)在BaP神经毒性中的作用 使用有效的学习和记忆、行为和运动功能测试的基因敲除小鼠，量化 神经递质和控制这些功能的大脑区域的基因表达。我们的初步研究发现 缺乏CYP1A1和CYP1A2的小鼠对发育中的苯并苯暴露的易感性增加。这些研究 将使我们能够在我们的小鼠模型中完成整个CYP1家族的表征。目标2：确定 与神经保护相关的肠道微生物群和下游代谢产物的变化 神经炎。在我们最初的研究中，我们能够对肠道微生物群进行探索性分析 在BaP处理组和对照组中，Cyp1a1(+/+)野生型和Cyp1a1(-/-)基因敲除的水坝和幼崽。我们发现重要的是 暴露于苯并苯的基因敲除中的β多样性差异。使用靶向代谢组学方法，我们还发现 BaP基因敲除小鼠体内色氨酸-犬尿氨酸途径的显著差异。这些数据 最近发现AHR激活和Trp-Kyn通路失调之间的联系的研究表明 一种潜在的神经毒性机制。作为R15领域的应用，这将加强研究 北肯塔基大学的环境，这是一所位于大辛辛那提的主要本科生机构 为大多数不同和弱势学生提供服务的地区，并支持早期调查人员 世卫组织可以培训这些学生使用生物信息学技术。

Project Summary. This is a renewal application of an initial award to explore genetic susceptibility to benzo[a]pyrene (BaP)-induced developmental neurotoxicity. BaP is a model polycyclic aromatic hydrocarbon found in traffic-related air pollution (TRAP), wildfire and cigarette smoke and grilled foods. Human studies have linked prenatal and early life exposure to PAHs with adverse effects on cognition and behavior persisting from early childhood to adolescence. Extensive animal studies have strongly implicated aryl hydrocarbon receptor (AHR) agonists including PAHs in developmental neurotoxicity. Our initial studies used mice with genetic differences in the AHR and two metabolic enzymes regulated by the AHR: CYP1A1 and CYP1A2. All three genes of interest vary in the human population and have been linked to adverse effects following exposure to TRAP. Data from our initial studies strongly supported our hypothesis that the AHR pathway plays a key role in mediating BaP developmental neurotoxicity. Both Cyp1a1(-/-) and Cyp1a2(-/-) knockout mice had greater impairments in tests of learning and memory compared with wild type mice exposed to the same dose of BaP during gestation and lactation. Interestingly, we also found differences in behavior based on genotype alone in the knockout lines. This novel finding suggests both genes have a normal role in brain development or function. Both humans and mice have three members of the CYP1 family, so our future work will probe the significance of CYP1B1 and further explore mechanisms of neurotoxicity in the Cyp1a1 and Cyp1a2 knockouts. Aim 1: Determine the role of CYP1B1 in BaP neurotoxicity by comparing Cyp1b1(+/+) wild type and Cyp1b1(-/-) knockout mice using validated tests of learning & memory, behavior, and motor function, quantification of neurotransmitters and gene expression in brain regions governing those functions. Our initial studies uncovered increased susceptibility to developmental BaP exposure in mice lacking CYP1A1 and CYP1A2. These studies will allow us to complete the characterization of the entire CYP1 family in our mouse model. Aim 2: Identify changes in the gut microbiome and downstream metabolites associated with neuroprotection v neuroinflammation. During our initial studies, we were able to do an exploratory analysis of the gut microbiome in BaP-treated and control Cyp1a1(+/+) wild type and Cyp1a1(-/-) knockout dams and pups. We found significant differences in beta diversity in BaP-exposed knockouts. Using a targeted metabolomics approach, we also found striking differences in the tryptophan-kynurenine pathway in BaP treated Cyp1a2(-/-) knockout mice. These data and recent studies identifying links between AHR activation and dysregulation of the TRP-KYN pathway suggest a potential mechanism of neurotoxicity. As an AREA-R15 application, this will strengthen the research environment at Northern Kentucky University, a predominantly undergraduate institution in the Greater Cincinnati area serving a large percentage of diverse and disadvantaged students and support an Early Stage Investigator who can train these students in the use of bioinformatics techniques.