Synaptic mechanisms of functional recovery after stroke

中风后的功能重绘依赖于皮层电路的重新布线。这些结构 电路的修改可能取决于个体细胞分子结构的纳米级改变， 产生交替连接并加强幸存联系的突触。NMDA和AMPA型 谷氨酸受体在调节突触的结构和功能可塑性中起关键作用。 中风后，通过AMPAR和NMDAR的信号发生变化，这可能是由于它们的变化。 纳米定位突触的小尺寸使我们无法理解突触是如何 中风会改变纳米结构，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。我们的建议旨在打破 通过结合最先进的STED超分辨率成像与行为分析， 感觉运动功能的小鼠模型中风。我们的初步数据表明，AMPAR和 NMDAR表现出相对于脊柱大小和突触前释放位点的不同组织原则， 这表明精确的纳米级规则控制着突触传递和可塑性。我们将 测试假设，即精确的纳米级重塑个别脊柱突触的基础， 中风后的功能恢复在aim 1中，我们将确定突触前和突触后 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） 在中风后恢复的早期和晚期阶段，我们将建立如何改变突触的组成部分， 突触纳米结构与年轻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ephrin-B3在皮质上脊柱纳米结构重塑中的作用， 中风恢复期的锥体神经元。测试ephrin-B3缺陷小鼠的感觉运动行为 范例，我们将确定肝配蛋白-B3是否需要中风后的功能恢复。 最后，使用体感皮层树突棘的双光子和STED成像，我们将 确定ephrin-B3是否调节中风后的突触重塑。新的分子见解 这项研究将提高我们对中风病理学的理解， 功能恢复的机械基础。

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.