Calcium-Dependent Regulation of Neural Fate in Development and Disease

项目总结/摘要 钙通道Cav1.2和钙调神经磷酸酶（CaN）下游钙信号蛋白突变/ NFAT通路，特别是激酶Dyrk 1a，已经可重复地与神经精神疾病相关。 自闭症谱系障碍（ASD）。这些基因发现暗示了钙信号 精神疾病中的功能障碍，并强调了我们对钙信号如何 在发育中的大脑中启动和传导。我们的长期目标是了解细胞内钙离子 神经祖细胞（NPC）的升高指导其分化为神经元和神经胶质， 旨在揭示钙信号蛋白的突变如何改变其发育功能， 疾病在这个提议中，我们关注钙信号的两个不同方面：检测器和传感器， 启动对外源性信号的钙反应或细胞内钙储备的耗竭，以及分子途径 作为钙信号的下游转换器。 我们已经发现，两个疾病相关Cav1.2外显子的利用是动态调节的， 胚胎皮层，并且Cav1.2中的ASD相关突变阻止了这种发育剪接开关 在通道转录本，这反过来又改变了特定的皮层神经元亚型的分化。同样我们 他们还发现，STIM 2的剪接，一种参与钙池操纵的钙进入（SOCE）的钙传感器， 对ER钙耗竭的反应，在发育过程中受到调节，产生两种具有相反作用的亚型 关于SOCE使用子宫内双向电穿孔改变NPC中这些亚型的相对水平 在体内调节细胞周期退出。最后，在携带前脑特异性Dyrk 1a缺失的小鼠中， 拮抗CaN/NFAT信号，我们已经观察到NPC功能和分化的广泛失调。 在这些已发表的初步研究的基础上，本建议的中心目标是询问 细胞内钙信号将细胞外信号与内在分化联系起来的特殊机制 程序，并阐明如何选择性剪接细化这些信号。拟议的研究将测试 钙离子进入，精确定时外显子利用调控，协调分化的假说 在发育中的皮质（Aim 1）程序，并通过下游细胞类型特异性钙信号传导， CaN/NFAT通路是参与NPC功能和分化调节的关键机制（Aim 2）。 这项研究将通过阐明发育神经科学领域的发展， 调节分化细胞中的钙信号传导，为未来的研究奠定基础， 了解细胞外信号和细胞内钙动力学如何汇聚在一起来调节大脑 发展我们的研究结果也将通过提供新的见解， 精神疾病的病理生理学机制。

PROJECT SUMMARY/ABSTRACT Mutations in the calcium channel Cav1.2 and downstream calcium signaling proteins in the calcineurin (CaN)/ NFAT pathway, in particular the kinase Dyrk1a, have been reproducibly associated with neuropsychiatric disorders, including autism spectrum disorders (ASD). These genetic findings implicate calcium signaling dysfunction in psychiatric disease and underscore a critical gap in our knowledge of how calcium signals are initiated and transduced in the developing brain. Our long-term goal is to understand how intracellular calcium elevations in neural progenitor cells (NPCs) direct their differentiation into neurons and glia, with an eye towards uncovering how mutations in calcium signaling proteins alter their developmental functions to promote disease. In this proposal, we focus on two distinct aspects of calcium signaling: detectors and sensors that initiate calcium responses to extrinsic cues or depletion of intracellular calcium stores, and molecular pathways that act as downstream transducers of calcium signals. We have found that utilization of two disease-relevant Cav1.2 exons is dynamically regulated in the embryonic cortex, and that an ASD-associated mutation in Cav1.2 prevents this developmental splicing switch in channel transcripts, which in turn alters the differentiation of specific cortical neuron subtypes. Similarly, we have also found that splicing of STIM2, a calcium sensor involved in store operated calcium entry (SOCE) in response to ER calcium depletion, is developmentally regulated to generate two isoforms with opposing effects on SOCE. Altering the relative levels of these isoforms in NPCs using in utero electroporation bidirectionally modulates cell cycle exit in vivo. Finally, in mice bearing a forebrain-specific deletion of Dyrk1a, a kinase that antagonizes CaN/NFAT signaling, we have observed broad misregulation of NPC function and differentiation. Building on these published and preliminary studies, the central objective of this proposal is to interrogate specific mechanisms by which intracellular calcium signals link extracellular cues with intrinsic differentiation programs and to elucidate how alternative splicing refines these signals. The proposed studies will test the hypotheses that calcium entry, regulated by precisely-timed exon utilization, orchestrates differentiation programs in the developing cortex (Aim1), and that downstream cell type-specific calcium signaling via the CaN/NFAT pathway is a key mechanism involved in the regulation of NPC function and differentiation (Aim2). This research will broadly impact the field of developmental neuroscience by elucidating the developmental regulation of calcium signaling in differentiating cells, building a foundation for future studies aimed at understanding how extracellular cues and intracellular calcium dynamics converge to regulate brain development. Our results will also have significant translational potential by providing new insights into mechanisms underlying the pathophysiology of psychiatric disorders.