Investigation into the mechanisms for generating interneuron diversity

描述(申请人提供)：GABA能中间神经元是神经系统抑制的主要来源，在每一个大脑回路中发挥关键作用。皮质中间神经元的异常发育和功能与精神分裂症、自闭症和癫痫等许多神经疾病的病理生物学有关。由于这些疾病的发病发生在成年之前，因此需要更好地了解正常发育和疾病模型中的神经元间分化和成熟。这款K99/R00应用程序将支持Timothy Petros博士开发创新策略和获取研究神经元间发育的新技能。这些实验将在指导期间启动(在纽约大学戈德·菲舍尔博士的实验室进行)，并在获得独立职位后在彼得罗斯博士自己的实验室继续进行。彼得罗斯博士的长期职业目标是解开指导神经元间命运决定和成熟的机制，希望为治疗各种神经疾病开发新的治疗靶点。Petros博士以前的工作发现了一种新的机制来调控来自内侧神经节隆起(MGE)的最大的、与临床相关的中间神经元群体的命运：小白蛋白表达(PV+)细胞优先通过间接神经发生来自中间神经前体细胞(INPs)，而直接神经发生主要产生生长抑素表达(SST+)的中间神经元。调控这一决定的分子机制尚不清楚，但初步数据表明，Jagged1和Noch信号在这一过程中具有很强的参与潜力。特定目标1将利用多个 采用体外和体内方法研究Jagged1抑制MGE中的Noch活性以促进SST+细胞的直接神经发生和形成的假设。MGE是一个异质的祖细胞群体，可以产生许多不同的细胞类型，由于生长抑素和小白蛋白在MGE中不表达，我们目前缺乏区分这些细胞的细胞标记和遗传策略。理想情况下，我们希望确定在MGE中经历命运决定的细胞的转录图谱，同时保留识别它在出生后大脑中成为哪种类型的中间神经元(PV+或SST+)的能力。为此，特定目标2将创建空间受限和时间可诱导的形式 大坝识别(DAMID)对MGE前体的转录组进行“时间标记”，以供将来分析。最初的实验将利用ESC技术，这将导致产生新的小鼠品系，以识别SST+和PV+中间神经元中新的命运决定基因。重要的是，拟议中的实验应该会显著提高我们对中间神经元发育的理解，并为彼得罗斯博士在学术界获得独立地位铺平道路。

DESCRIPTION (provided by applicant): GABAergic interneurons are the primary source of inhibition in the nervous system and play critical roles in every brain circuit. The abnormal development and function of cortical interneurons has been implicated in the pathobiology of many neurological disorders such as schizophrenia, autism, and epilepsy. As the onset of these diseases presents prior to adulthood, a better understanding of interneuron differentiation and maturation in normal development and disease models is required. This K99/R00 application will support Dr. Timothy Petros in his pursuit of developing innovative strategies and acquiring new skill sets to study interneuron development. The experiments will be initiated during the mentored period (carried out in Dr. Gord Fishell's lab at NYU) and continue in Dr. Petros' own laboratory upon securing an independent position. Dr. Petros' long-term career goal is to unravel the mechanisms that direct interneuron fate determination and maturation, with the hope of developing new therapeutic targets for treating a variety of neurological diseases. Dr. Petros' previous work has identified a novel mechanism regulating fate decisions for the largest, clinically- relevant interneuron populations arising from the medial ganglionic eminence (MGE): parvalbumin-expressing (PV+) cells preferentially arise from intermediate neuronal progenitors (INPs) via indirect neurogenesis whereas direct neurogenesis primarily gives rise to somatostatin-expressing (Sst+) interneurons. The molecular mechanisms that regulate this decision remain unknown, but out preliminary data demonstrate a strong potential for involvement of Jagged1 and notch signaling in this process. Specific Aim 1 will utilize multiple in vitro and in vivo approaches to investigate the hypothesis that Jagged1 inhibits notch activity in the MGE to promote direct neurogenesis and formation of Sst+ cells. The MGE is a heterogeneous population of progenitors that gives rise to many different cell types, and since somatostatin and parvalbumin are not expressed in the MGE, we currently lack cell markers and genetic strategies to distinguish these cells. Ideally, we would like to determine the transcriptional profile of a cell undergoing fate decisions in the MGE while at the same time retain the ability to identify which type of interneuron (PV+ or Sst+) it becomes in the postnatal brain. To this end, Specific Aim 2 will create a spatially restricted and temporally inducible form of Dam-identification (DamID) to 'time-stamp' the transcriptome of MGE progenitors for future analysis. Initial experiments will utilize ESC technology that will lead to generation of new mouse strains to identify novel fate-determining genes in Sst+ and PV+ interneurons. Importantly, the proposed experiments should significantly advance our understanding of interneuron development and pave the way for Dr. Petros to secure an independent position in academia.