Proteomic reconstructive microscopy of healthy and diseased dendrites

描述(申请人提供)：在过去的几十年里，我们对离子通道的多样性及其在神经元电信号中的作用的了解呈指数级增长。这些进展有助于理解和治疗一些大脑疾病，但许多其他常见大脑疾病背后的机制仍有待发现。事实上，就检查的程度而言，这些情况中的许多都与突触或通道异常有关，包括在青春期出现的异常，随着年龄的增长，或由于经验(例如，药物暴露症，创伤后应激障碍)。因此，加深我们对离子通道、突触、树突和脑疾病之间的联系的理解是基础和临床神经科学研究的基本目标。这种努力的一个关键瓶颈是薄树突起仍然无法被膜片钳生理学获得，这项技术负责我们对树突和神经元整合的大部分了解。因此，我们对神经元和树突功能的理解主要是基于来自大直径树突记录和计算模型的推论的组合。为了绕过这些限制并填补关键的知识空白，该项目将使用AT或近超微结构分辨技术确定海马CA1区锥体神经元完整树突的几个关键配体和电压门控离子通道的表达模式。为了实现这一目标，拟议的实验将分别将场发射扫描电子显微镜(FESEM)和阵列断层扫描(AT)与免疫金或免疫荧光通道检测相结合。这种方法将填补我们对小鼠和人类的单树突状蛋白质组知识的有限空白。而且，如果成功，该方法有可能彻底改变我们对离子通道在树突/神经元功能中的作用的理解，因为整个大脑中单个神经元的树突内运输网络和表达水平可能会有所不同。最后，为了验证这种方法的潜在临床/翻译相关性，在两种不同的阿尔茨海默病小鼠模型中出现的经络病将被急性逆转的药理学，然后用FESEM和AT来探测，以确定是否真的使表达恢复正常，或者这样的治疗是否诱导了功能性的、但不是恢复性的经络病逆转。

DESCRIPTION (provided by applicant): Over the last several decades, our understanding of the diversity of ion channels and their role in electrical signaling in neurons has increased exponentially. Such advances have helped understand and treat some brain disorders, but the mechanisms underlying many other common brain disorders remain to be discovered. In- deed, to the extent examined, many of these conditions are associated with synaptic or channelopathic abnormalities, including ones that emerge in adolescence, with aging, or as a result of experience (e.g., drug expo- sure, post-traumatic stress disorder). Deepening our understanding of the links among ion channels, synapses, dendrites, and brain disease is therefore a fundamental goal of both basic and clinical neuroscience research. One critical bottleneck to such an endeavor is that thin dendrites remain inaccessible to patch-clamp physiology, the technique responsible for much of our understanding with regard to dendritic and neuronal integration. Consequently, our understanding of neuronal and dendritic function is based primarily on a combination of inferences from large-diameter dendritic recordings and computational models. To circumvent such limitations and fill crucial knowledge gaps, this project will determine the expression patterns of several key ligand- and voltage-gated ion channels for entire, complete dendrites from hippocampal CA1 pyramidal neurons using at or near ultrastructural resolution techniques. To accomplish this, the proposed experiments will combine field emission scanning electron microscopy (FESEM) and array tomography (AT) with immunogold or immunoflourescence channel detection, respectively. Such an approach will fill limiting gaps in our knowledge of the single-dendrite proteome in both mice and humans. And, if successful, the proposed approach has the poten- tial to revolutionize our understanding of the role of ion channels in dendritic/neuronal function because trafficking networks and expression levels are likely to differ intradendritically in single neurons throughout the brain. Finally, to validate the potential clinical/translational relevance of such an approach, a channelopathy that emerges with age in two different mouse models of Alzheimer's disease will be acutely reversed pharmacologically, and then probed with FESEM and AT to determine whether expression is indeed rendered normal again, or whether such a treatment induces a functional, but not a restorative, reversal of the channelopathy.