Regulation of Forebrain Neurogenesis by the Energy Sensor AMP Kinase

描述(申请人提供)：哺乳动物的皮质发育是一个复杂和严格调控的过程。虽然已知体液和转录调控产生了哺乳动物端脑中的细胞多样性，但一个相对未被探索的领域是，前体细胞群体是否也在代谢上是不同的，以及前体细胞的代谢调控在多大程度上有助于端脑的神经发生。AMP激活的蛋白激酶(AMPK)是一种能量感受器，在所有真核细胞的能量和氧化还原动态平衡中起着核心作用。最近的研究表明，AMPK控制着许多基本的过程，包括调节细胞结构、极性、细胞分裂、迁移和生物体的正常生长发育。在这一应用中，我们将检验我们的假设，即AMPK通过其能量感应功能调节端脑的神经发生。AMPK以催化和调节的杂三聚体形式存在。亚单位。哺乳动物表达2？、2？和3？亚单位。对神经细胞中AMPK的功能知之甚少。在果蝇身上的研究表明，AMPK是维持神经前体有丝分裂能力所必需的，AMPK功能的丧失也会导致进行性神经退化。我们已发表的研究(Dev.在胚系突变小鼠中，细胞大量凋亡，主要限于胚胎发育中的端脑的中间前体细胞(IPC及其后代)，而在出生后的大脑中，细胞凋亡仅限于发育中的小脑的外部颗粒层。体外分析显示细胞固有的G2M特异性缺陷和突变型神经前体细胞的凋亡。在本应用程序中，我们将重点介绍端脑。在我们最近产生的条件基因敲除小鼠和其他转基因小鼠的帮助下，我们将进行生物能量学研究，以检验背侧和腹侧端脑IPC的代谢独特性是否使它们在增殖、存活、迁移和分化过程中对AMPK功能的丧失更加敏感(Aim1)。我们将通过使用区域特异性CRE线降低功能(AIM2)来研究活体背侧和腹侧端脑中？1对神经发生的区域控制。在Aim3中，我们将使用三项尖端技术在活体完整的大脑中研究特定区域的组织生物能量学和代谢组学。我们期待我们的研究将为我们从细胞代谢的角度理解皮质发育提供新的维度。新型AMPK效应器和AMPK亚单位特异性小分子调节剂的发现有朝一日可能会为神经退行性疾病和代谢性疾病带来新的治疗方法。

DESCRIPTION (provided by applicant): Mammalian cortical development is a complex and tightly regulated process. While it is known that humoral and transcriptional regulation generates the cellular diversity in the mammalian telencephalon, a relatively unexplored area is whether the progenitor populations are also metabolically distinct and the extent to which metabolic regulation of precursor cells contribute to neurogenesis in the telencephalon. AMP- activated protein kinase (AMPK) is an energy sensor and plays a central role in energy and redox homeostasis in all eukaryotic cells. Recent studies show, that AMPK controls many fundamental processes including regulation of cell structures, polarity, cell division, migration and normal growth and development of organisms. In this application we will test our hypothesis that AMPK regulates neurogenesis in the telencephalon though its energy sensing functions. AMPK exists as a heterotrimer of catalytic ¿ and regulatory ¿ and ? subunits. Mammals express 2¿, 2¿ and 3? subunits. Not much is known about AMPK function in neural cells. Studies in Drosophila demonstrate that AMPK is necessary for maintaining mitotic competence of neural precursors and loss of AMPK function also causes progressive neurodegeneration. Our published study (Dev. Cell, 2009) in the germline ¿1 mutant mice shows massive apoptosis, which was primarily restricted to the intermediate progenitors (IPCs and their progeny) of developing telencephalon in the prenatal embryo, while in the postnatal brain apoptosis was restricted to the external granule layer of the developing cerebellum. In vitro analysis showed cell-intrinsic G2M-specific defects and apoptosis of ¿1 mutant neural precursors. In this application, we will focus on the telencephalon. With the help of our recently generated ¿1 conditional knockout mouse and other transgenic mice, we will conduct bioenergetics studies to examine whether metabolic uniqueness of dorsal and ventral telencephalon IPCs render them more sensitive to loss of AMPK function during their proliferation, survival, migration and differentiation (Aim1). We will examine regional control of neurogenesis by ¿1 in the dorsal and ventral telencephalon in vivo, by using region-specific Cre lines to reduce ¿1 function (Aim2). In Aim3, we will use three cutting edge technologies to investigate region-specific tissue bioenergetics and metabolomics in the intact brain in vivo. We expect that our studies will provide new dimensions to our understanding of cortical development in the light of cellular metabolism. Identification of novel AMPK effectors and AMPK subunit-specific small molecule modulators could one day potentially lead to novel therapeutics for neurodegenerative and metabolic diseases.