培养的皮质和海马神经元在氧葡萄糖剥夺时,针对不同亚基具有独特的α-氨基-3-羟基-5-甲基-4-异恶唑丙酸(AMPA)受体转运机制。

Distinct subunit-specific α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor trafficking mechanisms in cultured cortical and hippocampal neurons in response to oxygen and glucose deprivation.

机构信息

From the School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom.

出版信息

J Biol Chem. 2014 Feb 21;289(8):4644-51. doi: 10.1074/jbc.M113.533182. Epub 2014 Jan 8.

Abstract

Brain ischemia occurs when the blood supply to the brain is interrupted, leading to oxygen and glucose deprivation (OGD). This triggers a cascade of events causing a synaptic accumulation of glutamate. Excessive activation of glutamate receptors results in excitotoxicity and delayed cell death in vulnerable neurons. Following global cerebral ischemia, hippocampal CA1 pyramidal neurons are more vulnerable to injury than their cortical counterparts. The mechanisms that underlie this difference are unclear. Cultured hippocampal neurons respond to OGD with a rapid internalization of AMPA receptor (AMPAR) subunit GluA2, resulting in a switch from GluA2-containing Ca(2+)-impermeable receptors to GluA2-lacking Ca(2+)-permeable subtypes (CP-AMPARs). GluA2 internalization is a critical component of OGD-induced cell death in hippocampal neurons. It is unknown how AMPAR trafficking is affected in cortical neurons following OGD. Here, we show that cultured cortical neurons are resistant to an OGD insult that causes cell death in hippocampal neurons. GluA1 is inserted at the plasma membrane in both cortical and hippocampal neurons in response to OGD. In contrast, OGD causes a rapid endocytosis of GluA2 in hippocampal neurons, which is absent in cortical neurons. These data demonstrate that populations of neurons with different vulnerabilities to OGD recruit distinct cell biological mechanisms in response to insult, and that a crucial aspect of the mechanism leading to OGD-induced cell death is absent in cortical neurons. This strongly suggests that the absence of OGD-induced GluA2 trafficking contributes to the relatively low vulnerability of cortical neurons to ischemia.

摘要

当大脑的血液供应中断时,就会发生脑缺血,导致氧气和葡萄糖剥夺(OGD)。这引发了一系列事件,导致谷氨酸的突触积累。谷氨酸受体的过度激活导致兴奋性毒性和脆弱神经元的迟发性细胞死亡。在全脑缺血后,海马 CA1 锥体神经元比皮质神经元更容易受到损伤。导致这种差异的机制尚不清楚。培养的海马神经元对 OGD 的反应是 AMPA 受体(AMPAR)亚基 GluA2 的快速内化,导致从含有 GluA2 的 Ca(2+)不可渗透受体向 GluA2 缺乏的 Ca(2+)可渗透亚型(CP-AMPARs)的转换。GluA2 内化是海马神经元中 OGD 诱导细胞死亡的关键组成部分。尚不清楚 OGD 后皮质神经元中的 AMPAR 转运如何受到影响。在这里,我们表明,培养的皮质神经元对引起海马神经元死亡的 OGD 损伤具有抗性。GluA1 在响应 OGD 时在皮质和海马神经元的质膜上插入。相比之下,OGD 导致海马神经元中 GluA2 的快速内吞,而皮质神经元中则没有。这些数据表明,对 OGD 具有不同易感性的神经元群体在受到损伤时会招募不同的细胞生物学机制,而导致 OGD 诱导细胞死亡的机制的一个关键方面在皮质神经元中缺失。这强烈表明 OGD 诱导的 GluA2 转运的缺失导致皮质神经元对缺血的相对低易感性。

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