Department of Neuroscience, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 Canada.
Neurobiol Dis. 2013 Jun;54:392-403. doi: 10.1016/j.nbd.2013.01.013. Epub 2013 Jan 27.
Excitotoxicity and neuronal death following ischemia involve AMPA (α-amino-3hydroxy-5-methylisoxazole-4-propionic acid) glutamate receptors. We have recently reported that the GluR2 subunit of AMPA receptors (AMPARs) forms a protein complex with GAPDH (glyceraldehyde-3-phosphate dehydrogenase). The GluR2/GAPDH complex co-internalizes upon activation of AMPA receptors. Disruption of the GluR2/GAPDH interaction with an interfering peptide protects cells against AMPAR-mediated excitotoxicity and protects against damage induced by oxygen-glucose deprivation (OGD), an in vitro model of brain ischemia.
We sought to test the hypothesis that disruption of the GluR2/GAPDH interaction with an interfering peptide would protect against ischemia-induced neuronal damage in vivo.
The rat 4-vessel occlusion (4-VO) model was used to investigate whether the GluR2/GAPDH interaction was enhanced in the hippocampus, and if our newly developed interfering peptide could protect against neuronal death in the ischemic brain area. The transient rat middle cerebral artery occlusion (tMCAo) model was used to determine whether our peptide could reduce infarction volume and improve neurological function. Finally, GAPDH lentiviral shRNA was injected into the brain to reduce GAPDH expression one week prior to tMCAo, to confirm the role of GAPDH in the pathophysiology of brain ischemia.
The GluR2/GAPDH interaction is upregulated in the hippocampus of rats subjected to transient global ischemia. Administration of an interfering peptide that is able to disrupt the GluR2/GAPDH interaction in vivo protects against ischemia-induced cell death in rat models of global ischemia and decreases the infarct volume as well as neurological score in a rat model focal ischemia. Consistent with these observations, decreased GAPDH expression also protects against ischemia-induced cell death in an animal model of focal ischemia.
Disruption of the GluR2/GAPDH interaction protects against ischemia-induced neuronal damage in vivo. The GluR2/GAPDH interaction may be a novel therapeutic target for development of treatment for ischemic stroke.
缺血后兴奋毒性和神经元死亡涉及 AMPA（α-氨基-3-羟基-5-甲基异恶唑-4-丙酸）谷氨酸受体。我们最近报道 AMPA 受体（AMPAR）的 GluR2 亚基与 GAPDH（甘油醛-3-磷酸脱氢酶）形成蛋白复合物。AMPAR 激活时，GluR2/GAPDH 复合物共内化。用干扰肽破坏 GluR2/GAPDH 相互作用可保护细胞免受 AMPAR 介导的兴奋毒性，并防止氧葡萄糖剥夺（OGD）引起的损伤，OGD 是脑缺血的体外模型。
我们试图检验这样一个假设，即用干扰肽破坏 GluR2/GAPDH 相互作用是否会在体内防止缺血引起的神经元损伤。
使用大鼠 4 血管闭塞（4-VO）模型来研究海马中 GluR2/GAPDH 相互作用是否增强，以及我们新开发的干扰肽是否可以防止缺血性脑区的神经元死亡。使用短暂性大鼠大脑中动脉闭塞（tMCAo）模型来确定我们的肽是否可以减少梗塞体积并改善神经功能。最后，在 tMCAo 前一周将 GAPDH 慢病毒 shRNA 注射到大脑中，以降低 GAPDH 的表达，从而确认 GAPDH 在脑缺血病理生理学中的作用。
在经历短暂性全脑缺血的大鼠海马中，GluR2/GAPDH 相互作用上调。体内给予能够破坏 GluR2/GAPDH 相互作用的干扰肽可防止全脑缺血模型大鼠的缺血性细胞死亡，并减少梗塞体积和神经评分在大鼠局灶性缺血模型中。与这些观察结果一致，降低 GAPDH 的表达也可以防止局灶性缺血动物模型中的缺血性细胞死亡。
破坏 GluR2/GAPDH 相互作用可防止体内缺血引起的神经元损伤。GluR2/GAPDH 相互作用可能是开发缺血性中风治疗方法的新的治疗靶点。
