Multimodal analysis of primate infragranular pyramidal neurons and their modulation

该项目的长期目标是确定细胞类型特异性表达的结果， 离子通道和神经调质受体基因对灵长类动物新皮层功能影响。人脑是 由数量惊人的细胞类型组成分子分析表明，超过75个独特的 神经元细胞类型存在于给定的新皮层区域中，并且每个区域具有专有的类型。怎么 基因表达的差异转化为神经元的表型特征？解决这个问题至关重要 因为一些新出现的证据表明，人类大脑疾病可能具有细胞类型特异性病因，其中不同类别的神经元对病理生理学有不同的贡献 疾病。 我们建议在人类和非人类灵长类动物中研究两种广泛的mRNA表达， 新皮质颗粒下锥体神经元的类别转化为它们独特的生理学， 形态学和对神经调节的反应。采用最先进的膜片钳技术 Patch-seq技术，我们可以从人类和非人类灵长类动物新皮层中遗传识别生理探测的神经元。我们测试了关于特定离子通道和神经调质 受体塑造了这些神经元的独特输入-输出特性。我们还利用病毒工具， 前瞻性地标记神经元，特别是第5层（L5）端脑外（ET）投射神经元（其 向大脑下区域发送轴突投射）。L_5ET神经元中有几种类型的神经元未被发现。 啮齿动物脑（例如，运动皮层的贝茨细胞）。 有三个因素使这一建议与人类健康和疾病特别相关。第一，L5 ET 神经元代表了新皮层对许多大脑下结构的唯一直接输出， 与包括阿尔茨海默病和肌萎缩侧索硬化症在内的几种神经系统疾病有关 （ALS）。第二，我们将直接在非人类灵长类动物和人类大脑切片中工作，而不是 传统的啮齿动物模型鉴于最近发表的主要研究结果，后一点尤其相关。 小鼠和人类锥体神经元生理学的差异。用猴子组织做的实验 提供直接进入体内长距离轴突投射靶（这对于人脑是不可行的 切片），以及研究大脑区域的能力，很少在人类从外科标本 (e.g.,初级运动皮层）。最后，该提案为最终的 开发细胞类型特异性遗传和药物治疗疾病。

The long-term goal of this project is to determine the consequences of cell-type specific expression of ion channel and neuromodulator receptor genes on primate neocortical function. The human brain is composed of an astonishing number of cell types. Molecular profiling suggests that upwards of ~75 unique neuronal cell types reside in a given neocortical area, and that each area has exclusive types. How do differences in gene expression translate into a neuron’s phenotypic identity? Solving this problem is crucial because several emerging lines of evidence suggest that human brain disorders may have cell type-specific etiologies, wherein different classes of neurons make distinct contributions to the pathophysiology of the disease. We propose to examine in human and nonhuman primates how mRNA expression in two broad categories of neocortical infragranular pyramidal neurons translates into their unique physiology, morphology and response to neuromodulation. Employing a state-of-the-art patch clamping technique, Patch-seq, we can genetically identify physiologically probed neurons from human and non-human primate neocortex. We test hypotheses about how specific ion channels and neuromodulator receptors shape the unique input-output properties of these neurons. We also utilize viral tools to prospectively label neurons, in particular the layer 5 (L5) extratelenephalic (ET)-projecting neurons (which send axonal projections to subcerebral regions). Several types of L5 ET neurons are not found in the rodent brain (e.g., Betz cells of motor cortex). Three factors make this proposal especially relevant for human health and disease. First, L5 ET neurons represent the sole direct output of the neocortex to many subcerebral structures and are implicated in several neurological disorders including Alzheimer’s disease and amyotrophic lateral sclerosis (ALS). Second, we will be directly working in non-human primate and human brain slices rather than the traditional rodent models. The latter point is especially pertinent given recent published findings of major differences in murine and human pyramidal neuron physiology. Experiments with monkey tissue will provide direct access to long-range axonal projection targets in vivo (which isn’t feasible for human brain slices), as well as the ability to study brain areas rarely available in the human from surgical specimens (e.g., primary motor cortex). Finally, this proposal lays the foundational knowledge necessary for eventual development of cell type-specific genetic and pharmacological treatment of disease.