Molecular Mechanisms of GABAergic Synapse Modulation by TAFA

项目摘要 神经元中依赖经验或使用的突触的形成和消除对发育至关重要 以及神经回路和信息存储的维护。对这些过程的异常控制被认为 对许多神经和精神疾病负有责任。长期目标是更好地理解 活性调节突触形成和消除以调节神经回路的分子机制 功能和行为。通过GABA能突触进行的抑制性突触传递是形成网络的关键 活动和维持神经回路功能。缺陷和异常的GABA能突触相关 有多种神经心理疾病，包括慢性疼痛、情绪障碍、精神分裂症和 阿尔茨海默氏症。像兴奋性突触一样，抑制性突触是高度动态的，并经历活动- 依赖的周转过程不仅在早期发育过程中，而且在成年大脑中也是如此。然而，分子 对抑制性突触的调节消除机制知之甚少。 神经调节剂在为神经回路操作和行为提供灵活性方面发挥着重要作用。虽然 越来越多的证据表明神经调节剂在控制GABA中的重要作用 突触，特异性神经调节剂(S)参与GABA能突触的减弱和消除 仍有待确认。TAFA2是一种脑特异性的新型趋化素样蛋白，由神经元表达。近期 使用TAFA2基因敲除动物的研究表明，TAFA2与焦虑和恐惧反应有关。 然而，TAFA2在大脑中发挥其功能的分子机制仍不清楚。这个 该项目的中心假设是TAFA2是一种新的神经调节剂，参与活动依赖的 消除抑制性突触。这一假设是基于初步数据提出的，这些数据表明 TAFA2的过表达和敲除对GABA能神经元的数量和强度有很强的影响 培养的海马神经元中的突触。因此，该项目的目标是描述和研究 TAFA2在GABA能突触传递和突触数量调控中的作用通过使用 多学科方法，包括生物化学、先进成像技术、电生理学和 在CRISPR-Cas9基因组编辑中，将追求以下三个具体目标来检验中心假设： 1)检测TAFA2对GABA能突触传递的快速调制作用。2)建立TAFA2 利用TAFA2基因敲除小鼠体内消除GABA能突触的功能。3)调查 TAFA2通过描绘下游信号转导途径和鉴定其作用机制 候选受体。这项拟议的研究具有重要意义，因为它有望推动和扩大 目前对突触强度和突触动态调控的分子机制的了解 数字。此外，这些知识最终可能有助于确定新的治疗靶点 神经心理障碍。

Project Summary Experience- or use-dependent synapse formation and elimination in neurons are critical for the development and maintenance of neural circuits and information storage. Aberrant control of these processes is thought responsible for numerous neurological and psychiatric diseases. The long-term goal is to better understand the molecular mechanisms by which activity regulates synapse formation and elimination to adjust neural circuit function and behavior. Inhibitory synaptic transmission via GABAergic synapses is critical for shaping network activity and maintaining neural circuit functionality. Defective and aberrant GABAergic synapses are associated with multiple neuropsychological conditions including chronic pain, mood disorders, schizophrenia, and Alzheimer's disease. Like excitatory synapses, inhibitory synapses are highly dynamic and undergo activity- dependent turnover processes not only during early development but also in adult brain. However, molecular mechanisms involved in the regulated elimination of inhibitory synapses are poorly understood. Neuromodulators play important roles in providing flexibility for neural circuit operation and behavior. Although there is a growing body of evidence indicating the important role of neuromodulators in the control of GABA synapses, specific neuromodulator(s) involved in the weakening and elimination of GABAergic synapses remains to be identified. TAFA2 is a brain-specific, novel chemokine-like protein expressed by neurons. Recent studies using TAFA2 gene knockout animals indicate that TAFA2 is involved in anxiety and fear responses. However, molecular mechanisms by which TAFA2 performs its functions in the brain remain unknown. The central hypothesis of this project is that TAFA2 is a novel neuromodulator involved in the activity-dependent elimination of inhibitory synapses. This hypothesis has been formulated based on the preliminary data showing that overexpression and knockdown of TAFA2 had strong effects on the strength and numbers of GABAergic synapses in cultured hippocampal neurons. The objective of the project is thus to characterize and study the function of TAFA2 in the control of GABAergic synaptic transmission and synapse numbers. By using multidisciplinary approaches including biochemistry, advanced imaging techniques, electrophysiology, and CRISPR-Cas9 genome editing, the following three specific aims will be pursued to test the central hypothesis: 1) Examine the rapid modulatory effect of TAFA2 on GABAergic synaptic transmission. 2) Establish TAFA2 function in the elimination of GABAergic synapses in vivo utilizing TAFA2 knockout mice. 3) Investigate mechanisms of TAFA2 action by delineating downstream signal transduction pathway and identifying its receptor candidates. The proposed research is significant, because it is expected to advance and expand the current understanding of the molecular mechanisms involved in the dynamic control of synapse strength and numbers. Moreover, such knowledge ultimately may help to identify new therapeutic targets for neuropsychological disorders.