Synaptic mechanisms of functional recovery after stroke

中风后功能的重新定位依赖于大脑皮层回路的重新连接。这些结构 电路的修改可能取决于个体分子结构的纳米级变化 产生交替连接并加强幸存联系的突触。NMDA型和AMPA型 谷氨酸受体在调节突触的结构和功能可塑性方面起着关键作用。 中风后，通过AMPAR和NMDAR的信号发生变化，可能是由于它们的 纳米级定位。突触的小尺寸阻碍了我们理解突触是如何 纳米结构因中风而改变，以及纳米级突触变化如何导致功能性 恢复，限制了我们针对突触进行中风干预的能力。我们的建议试图打破 这一障碍通过将最先进的STED超分辨率成像与行为分析相结合 卒中小鼠模型的感觉运动功能。我们的初步数据显示AMPAR和 NMDAR相对于脊柱大小和突触前释放部位表现出不同的组织原则， 这表明，支配突触传递和可塑性的正是一套纳米级规则。我们会 测试这一假设，即单个脊柱突触的精确纳米级重塑是 卒中后功能恢复。在目标1，我们将确定突触前和突触后的变化 皮质锥体神经元上的纳米结构与中风后的功能恢复有关。通过成像 脚手架的组织(PSD-95和巴松管)和功能(AMPAR、NMDAR、MUNC-13) 在卒中后恢复的早期和晚期，突触的成分，我们将确定如何变化 在突触中，纳米结构与幼年和老年小鼠感觉运动功能的恢复有关。 在目标2中，我们将确定ephin-B3在脊柱皮质纳米结构重塑中的作用。 中风恢复期的锥体神经元。检测eaffin-B3基因缺失小鼠的感觉运动行为 范型，我们将确定卒中后功能恢复是否需要eaffin-B3。 最后，使用双光子和STED成像对躯体感觉皮质中的树突进行成像，我们将 确定eaffin-B3是否调节中风后的突触重构。新的分子洞察 这项研究将提高我们对中风病理的理解，同时提供 机能恢复的机械性基础。

Remapping of function after stroke relies on the rewiring of cortical circuitry. These structural modifications of circuits likely depend on nanoscale alteration in the molecular architecture of individual synapses that generate alternate connectivity and strengthen surviving contacts. NMDA- and AMPA-type glutamate receptors play critical roles in regulating structural and functional plasticity of synapses. Following a stroke, the signaling via AMPARsand NMDARs changes, likely due to changes in their nanoscale localization. The small size of synapses has prevented us from understanding how synaptic nano-architecture is altered by stroke and how nanoscale synaptic changes might lead to functional recovery, limiting our ability to target synapses for stroke intervention. Our proposal seeks to break down this barrier by combining state-of-the-art STEDsuper-resolution imaging with behavioral analyses of sensorimotor function in the mouse model of stroke. Our preliminary data indicate that AMPARsand NMDARs exhibit distinct organizational principles relative to spine size and presynaptic release sites, suggesting that the exact set of nanoscale rules governs synaptic transmission and plasticity. We will test the hypothesis that precise nanoscale remodeling of individual spine synapses underlies the functional recovery after stroke. In aim 1, we will determine how changes in pre- and post-synaptic nano-architecture on cortical pyramidal neurons are linked to functional recovery after stroke. By imaging the organization of scaffolding (PSD-95 and Bassoon) and functional (AMPARs, NMDARs, Munc-13) components of synapses in early and late phases of recovery after stroke, we will establish how changes in synaptic nano-architecture relate to the recovery of sensorimotor function in both young and old mice. In aim 2, we will determine the role of ephrin-B3 on the remodeling of spine nano-architecture on cortical pyramidal neurons during stroke recovery. Testing ephrin-B3 null mice in sensorimotor behavioral paradigms, we will determine whether ephrin-B3 is required for the functional recovery after stroke. Finally, using two-photon and STEDimaging of dendritic spines in the somatosensory cortex, we will determine whether ephrin-B3 regulates synaptic remodeling after stroke. Novel molecular insights gained from this research will improve our understanding of stroke pathology while providing mechanistic underpinnings into functional recovery.