Regulation of Forebrain Neurogenesis by the Energy Sensor AMP Kinase

描述（由申请人提供）：哺乳动物皮质发育是一个复杂而严格调控的过程。虽然已知体液和转录调节产生哺乳动物端脑的细胞多样性，但一个相对未被探索的领域是，祖细胞群体是否也具有代谢差异，以及前体细胞的代谢调节在多大程度上促进了端脑的神经发生。AMP活化蛋白激酶（AMPK）是一种能量传感器，在所有真核细胞的能量和氧化还原稳态中起着核心作用。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。在这个应用中，我们将验证我们的假设，即AMPK通过其能量感应功能调节端脑的神经发生。AMPK作为催化和调节的异三聚体存在。子单元。哺乳动物表达2¿、2¿和3？子单元。我们对AMPK在神经细胞中的功能知之甚少。对果蝇的研究表明，AMPK对于维持神经前体的有丝分裂能力是必要的，AMPK功能的丧失也会导致进行性神经变性。我们发表的研究（Dev. Cell, 2009）在种系1突变小鼠中发现了大量的细胞凋亡，这种细胞凋亡主要局限于产前胚胎中发育的端脑的中间祖细胞（IPCs及其后代），而在出生后的脑凋亡则局限于发育中的小脑的外颗粒层。体外分析显示细胞内在的g2m特异性缺陷和¿1突变神经前体的凋亡。在本应用中，我们将重点关注端脑。我们将利用最近生成的¿1条件敲除小鼠和其他转基因小鼠，进行生物能量学研究，以检验背侧和腹侧端脑IPCs的代谢独特性是否使它们在增殖、存活、迁移和分化（Aim1）过程中对AMPK功能的丧失更敏感。我们将通过使用区域特异性Cre线来降低¿1功能，研究体内背端和腹端脑中¿1对神经发生的区域控制（Aim2）。在Aim3中，我们将使用三种前沿技术来研究完整大脑体内区域特异性组织生物能量学和代谢组学。我们期望我们的研究将为我们在细胞代谢的基础上理解皮层发育提供新的维度。新的AMPK效应物和AMPK亚基特异性小分子调节剂的鉴定有一天可能会导致神经退行性和代谢性疾病的新疗法。

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.