A role for EphB and NMDARs in dendritic spine formation

描述（由申请人提供）： CNS中的大多数成熟兴奋性突触发生在被称为树突棘的特化形态结构上，并且从细胞培养中的研究中清楚的是，EphB受体酪氨酸激酶和NMDAR参与适当的棘和突触形成。最近的工作还表明，活化的EphB可以募集和调节NMDAR的功能。该提议的目的1将通过检查和操纵来自EphB缺失小鼠的神经元来确定由EphB受体信号传导调节的树突棘形态发生的步骤。目的2将评估激活的EphB在更复杂的系统中招募NMDAR的能力，皮质切片培养，使用荧光标记的受体和双光子显微镜。最后，EphB和NMDAR的已知相互作用表明在树突棘发育过程中的协调作用; Aim 3将使用药理学直接测试皮质切片中的这种合作活性以操纵受体功能和双光子成像以可视化棘形态。增加对这些分子机制的理解对于解决人类神经系统疾病至关重要，这些疾病的表型包括异常脊柱形成，如脆性X、Down和Rett Syndrome。

DESCRIPTION (provided by applicant): The majority of mature excitatory synapses in the CNS occur on specialized morphologic structures known as dendritic spines, and it is clear from studies in cell culture that the EphB receptor tyrosine kinase and the NMDAR are involved in proper spine and synapse formation. Recent work has also shown that activated EphB can both recruit and modulate the function of NMDARs. Aim 1 of this proposal will determine the steps of dendritic spine morphogenesis that are regulated by EphB receptor signaling by examining and manipulating neurons over time from EphB null mice. Aim 2 will assess the ability of activated EphB to recruit NMDARs in a more complex system, cortical slice culture, using fluorescently-tagged receptors and two-photon microscopy. Finally, the known interaction of EphB and NMDARs suggests a coordinated role during the development of dendritic spines; Aim 3 will directly test for this cooperative activity in cortical slice using pharmacology to manipulate receptor function and two-photon imaging to visualize spine morphology. Increased understanding of these molecular mechanisms is critical in addressing human neurologic diseases whose phenotype include abnormal spine formation, such as Fragile X, Down, and Rett Syndromes.