Increased surface P2X4 receptor regulates anxiety and memory in P2X4 internalization-defective knock-in mice
Increased surface P2X4 receptor regulates anxiety and memory in P2X4 internalization-defective knock-in mice
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DOI：
10.1038/s41380-019-0641-8
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发表时间：
2020-01-08
影响因子：
11
通讯作者：
Boue-Grabot, Eric
中科院分区：
文献类型：
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作者：
Bertin, Eleonore;Deluc, Thomas;Boue-Grabot, Eric
ATP信号传导和表面P2 X4受体在各种CNS病症（包括焦虑、慢性疼痛、癫痫、缺血和神经变性疾病）中的神经元和/或神经胶质中选择性上调。然而，P2 X4在病理环境中的细胞特异性功能仍然难以捉摸。为了阐明P2 X4的功能，我们创建了条件性转基因敲入P2 X4小鼠系（Floxed P2 X4 mCherryIN），其允许通过荧光mCherry蛋白对P2 X4的内化基序进行Cre活性依赖性遗传交换，以防止P2 X4的组成性内吞作用。通过结合分子、细胞、电生理和行为方法，我们表征了两种不同的敲入小鼠系，它们表达非内化的P2 X4 mCherryIN，要么仅在兴奋性前脑神经元中，要么在所有天然表达P2 X4的细胞中。在两种敲入小鼠模型中，野生型P2 X4被非内化P2 X4 mCherryIN的遗传取代没有改变P2 X4的稀疏分布和亚细胞定位，但增加了靶细胞表面P2 X4受体的数量，模拟了病理性增加的表面P2 X4状态。敲入小鼠海马中表面P2 X4密度的增加改变了CA 1突触的LTP和LTD可塑性现象，而不影响基础兴奋性传递。此外，这些细胞事件转化为抗焦虑作用和空间记忆缺陷。我们的研究结果表明，神经元P2 X4的表面密度增加有助于突触缺陷和改变焦虑和记忆功能与P2 X4在神经精神和神经退行性疾病的含义一致。此外，这些条件性P2 X4 mCherryIN敲入小鼠将允许探索P2 X4在各种生理和病理背景中的细胞特异性作用。
ATP signaling and surface P2X4 receptors are upregulated selectively in neurons and/or glia in various CNS disorders including anxiety, chronic pain, epilepsy, ischemia, and neurodegenerative diseases. However, the cell-specific functions of P2X4 in pathological contexts remain elusive. To elucidate P2X4 functions, we created a conditional transgenic knock-in P2X4 mouse line (Floxed P2X4mCherryIN) allowing the Cre activity-dependent genetic swapping of the internalization motif of P2X4 by the fluorescent mCherry protein to prevent constitutive endocytosis of P2X4. By combining molecular, cellular, electrophysiological, and behavioral approaches, we characterized two distinct knock-in mouse lines expressing noninternalized P2X4mCherryIN either exclusively in excitatory forebrain neurons or in all cells natively expressing P2X4. The genetic substitution of wild-type P2X4 by noninternalized P2X4mCherryIN in both knock-in mouse models did not alter the sparse distribution and subcellular localization of P2X4 but increased the number of P2X4 receptors at the surface of the targeted cells mimicking the pathological increased surface P2X4 state. Increased surface P2X4 density in the hippocampus of knock-in mice altered LTP and LTD plasticity phenomena at CA1 synapses without affecting basal excitatory transmission. Moreover, these cellular events translated into anxiolytic effects and deficits in spatial memory. Our results show that increased surface density of neuronal P2X4 contributes to synaptic deficits and alterations in anxiety and memory functions consistent with the implication of P2X4 in neuropsychiatric and neurodegenerative disorders. Furthermore, these conditional P2X4mCherryIN knock-in mice will allow exploring the cell-specific roles of P2X4 in various physiological and pathological contexts.