MotAct-CSF - Characterization of CSF-contacting neurons physiological rolein the mammalian nervous system

本研究旨在阐明哺乳动物中枢神经系统中接触脑脊液神经元(CSF-CNS)的生理、分子和解剖特性。脑脊液-中枢神经系统是一种独特的神经细胞群，从低等脊椎动物到灵长类动物，排列在中央管(CC)的所有脊髓水平，其特征是选择性地表达多囊肾病2-样1通道(PKD2L1)。这些神经元是高度极化的细胞，树突投射到中央管并与脑脊液接触形成一个大的突起，而轴突似乎沿着腹侧脊髓的纵轴延伸到实质中。在最近的研究中，我们对小鼠延髓脑脊液的生理和解剖学特征进行了开创性的研究，展示了功能性离子受体的表达和能够调节脑脊液-中枢神经系统兴奋性的自发的PKD2L1通道活动。我们还描述了脑脊液-中枢神经系统在CC周围的定位在不同节段水平上的不同，提示了沿着中枢神经系统吻尾轴的生理特性、回路和功能的潜在差异。通过结合电生理、钙成像、分子和病毒示踪技术，我们首次提出根据以下特定目标确定哺乳动物不同脊髓水平的脑脊液-中枢神经系统的分子图谱、细胞和连接特性：目的1-脑脊液-中枢神经系统的生理学和突触整合A、脑脊液-中枢神经系统电生理特性和钙稳态B。分离的脊髓脊液-神经干细胞的区域特异性转录。脑脊液-中枢神经系统输入/输出关系的识别及其活性的调节目的2-脑脊液-中枢神经系统输入-输出连接性的特征A。脑脊液-中枢神经系统投射模式和突触前终末的识别标测脑脊液-中枢神经系统回路C。脑脊液-中枢神经系统突触前和突触后伙伴的识别拟议的研究将促进我们目前对脑脊液-中枢神经系统生物学的理解，以全面描述它们在脊髓系统不同水平上的分子和细胞特性。此外，我们将从解剖学和功能上确定CSF-CNS所插入的特定神经元网络。总之，这些数据将是确定脑脊液-中枢神经系统在哺乳动物中枢神经系统中功能的必要步骤。

This proposal aims at elucidating the physiological, molecular and anatomical properties of cerebrospinal fluid-contacting neurons (CSF-cNs) in the mammalian central nervous system. CSF-cNs are a unique neuronal population, conserved from lower vertebrates to primates, lining the central canal (CC) at all medullospinal levels and are characterized by selective expression of the Polycystin Kidney Disease 2-Like 1 channel (PKD2L1) These neurons are highly polarized cells with a dendrite projecting to the CC and forming a large protrusion in contact with the CSF, while their axons appear to extend in the parenchyma along the longitudinal axis of the ventral spinal cord. CSF-cNs are strategically positioned to monitor CSF composition and sense mechanical deformation of the spine, thus possible functions in providing sensory information about the physiological and/or postural state of the organism have been hypothesized.In recent studies, we conducted pioneering characterization of the physiology and anatomy of mouse medullar CSF-cNs, demonstrating expression of functional ionotropic receptors and spontaneous PKD2L1 channel activity capable of regulating CSF-cNs excitability. We also described that CSF-cNs positioning around the CC varies at different segmental levels, suggesting potential differences in physiological properties, circuitry and function along the rostro-caudal axis of CNS. However, to date, the role of CSF-cNs in the central nervous system remains unknown.By combining electrophysiological, calcium imaging, molecular and viral tracing techniques, we propose to determine for the first time in mammals the molecular profile, cellular and connectivity properties of CSF-cNs at different medullospinal levels according to the following specific aims:AIM 1 - Physiology and synaptic integration of CSF-cNs A. CSF-cNs electrophysiological properties and calcium homeostasisB. Region specific transcriptomic on isolated medullospinal CSF-cNsC. Identification of CSF-cNs input/output relationships and modulation of their activityAIM 2 - Characterization of CSF-cNs input-output connectivityA. Identification of CSF-cNs projection patterns and pre-synaptic terminalsB. Mapping CSF-cNs circuitsC. Identification of CSF-cNs pre- and post-synaptic partnersThe proposed studies will advance our current understanding of CSF-cNs biology to fully characterize their molecular and cellular properties at different levels of the medullospinal system. Moreover, we will determine both anatomically and functionally the specific neuronal networks CSF-cNs are inserted in. Altogether, these data will be a necessary step to define the function of CSF-cNs in the mammalian central nervous system.