Toxicant Induced dysregulation of parvalbumin interneuron development and function

项目摘要/摘要 神经疾病和精神障碍约占全球疾病负担的28%。我们有能力 这些疾病和障碍的预防和治疗受到其复杂、多因素病因的阻碍。我们的长- 学期目标是通过使用功能神经成像来帮助预防神经疾病和精神障碍 斑马鱼研究以了解神经种群在危重期间对毒物暴露的敏感性 发展阶段。兴奋性和抑制性信号平衡的破坏导致了许多 神经疾病和精神障碍，包括多动症，自闭症，智力残疾， 精神分裂症、癫痫和阿尔茨海默病。将这些不同的疾病和 疾病是指小白蛋白(PV)中间神经元发育受阻。我们的直接目标是获得洞察力 深入到调节光伏发育和功能的分子机制，以及这些关键的发育 接触有毒物质会扰乱这一过程。为了实现这一目标，我们正在开发一套遗传工具 用于可视化活体中PV中间神经元的发育、连接和功能，以及 在PV中间神经元中特异地操纵基因功能。此外，我们正在培育转基因品系， 使我们能够在我们的PV中间神经元的背景下可视化兴奋电路的组装和功能- 特定的操作。我们的初步数据表明，已知的GABA能和PV的调节因子dlx1、5和6 暴露于2，3，7，8-三氯苯酚后，神经元间发育和多种PV亚型的表达下调。 四氯二苯并对二恶英(TCDD)，一种典型的芳香烃受体(AHR)激动剂。在目标1中， 我们将利用我们的遗传工具包和功能神经成像来确定是否暴露于不同的AHR激动剂 破坏PV中间神经元的发育和功能。我们将使用细胞类型特定的基因操作来 激活PV中间神经元中的AHR并确定AHR激活是否改变了PV中间神经元的功能，组装 在发育中的大脑中的兴奋回路，并足以产生幼虫的过度活动以及 成人的学习和记忆。哺乳动物Sox9和斑马鱼Sox9b是AHR的靶标，也下调了表达 在接触到包括邻苯二甲酸单丁酯、6：2氯化多氟醚在内的多种毒物后 磺酸盐、丙戊酸和毒死蜱。哺乳动物Sox9标记了辐射祖细胞(RGP)，这是一种重要的 GABA能中间神经元的来源。在目标2中，我们将确定斑马鱼sox9b是否是一个重要的 光伏发育的转录调节因子，以及光伏中间神经元特异性sox9b的丢失是否足以扰乱 PV中间神经元功能与幼虫和成虫行为。在目标3中，我们将使用神经的光转换指示器 活性以确定AHR激动剂暴露对胚胎和幼虫脑功能的不同影响。 总之，这些研究将为调节PV中间神经元的分子机制提供深入的见解。 这一关键细胞类型的发育和毒物诱导的破坏。拟议的研究直接有助于 NIEHS的战略目标1，c、d和e部分。

PROJECT SUMMARY/ABSTRACT Neurological diseases and psychiatric disorders account for ~28% of the global burden of disease. Our ability to prevent and treat these diseases and disorders is hindered by their complex, multifactorial etiologies. Our long- term goal is to help prevent neurological diseases and psychiatric disorders by using functional neuroimaging studies in zebrafish to understand the susceptibility of neural populations to toxicant exposures during critical periods of development. Disruptions in the balance of excitatory and inhibitory signaling contribute to a number of neurological diseases and psychiatric disorders including hyperactivity, autism, intellectual disabilities, schizophrenia, epilepsy, and Alzheimer’s Disease. A common theme connecting these diverse diseases and disorders is the disrupted development of parvalbumin (PV) interneurons. Our immediate goal is to gain insight into the molecular mechanisms mediating PV development and function and how these critical developmental processes are disrupted by toxicant exposure. To achieve this goal, we are developing a suite of genetic tools for visualizing the development, connectivity, and functioning of PV interneurons in vivo as well as tools for manipulating gene function specifically in PV interneurons. In addition, we are generating transgenic lines that allow us to visualize the assembly and functioning of excitatory circuitry in the context of our PV interneuron- specific manipulations. Our preliminary data indicate that dlx1, 5 and 6, known regulators of GABAergic and PV interneuron development, and multiple isoforms of PV, are downregulated following exposure to 2,3,7,8- Tetrachlorodibenzo-p-dioxin (dioxin, TCDD), a prototypical aryl hydrocarbon receptor (AHR) agonist. In Aim 1, we will utilize our genetic tool kit and functional neuroimaging to determine if exposure to different AHR agonists disrupts PV interneuron development and function. We will use cell-type specific genetic manipulations to activate AHR in PV interneurons and determine if AHR activation alters PV interneuron function, the assembly of excitatory circuits in the developing brain, and is sufficient to produce larval hyperactivity as well as deficits in adult learning and memory. Mammalian Sox9 and zebrafish sox9b are AHR targets and are also downregulated following exposure to a number of toxicants including mono-butyl phthalate, 6:2 chlorinated polyfluorinated ether sulfonate, valproic acid, and chlorpyrifos. Mammalian Sox9 marks radial progenitor cells (RGP), an important source of GABAergic interneurons. In Aim 2, we will determine whether zebrafish sox9b is an important transcriptional regulator of PV development, and if PV-interneuron specific loss of sox9b is sufficient to disrupt PV interneuron function and larval and adult behavior. In Aim 3, we will use photoconvertible indicators of neural activity to determine the differential effects of AHR agonist exposure on embryonic and larval brain function. Together, these studies will provide insight into the molecular mechanisms mediating PV interneuron development and toxicant-induced disruption of this critical cell-type. The proposed studies directly contribute to NIEHS’s Strategic Goal 1, parts c, d, & e.