Deletion of TRPC6 Attenuates NMDA Receptor-Mediated Ca(2+) Entry and Ca(2+)-Induced Neurotoxicity Following Cerebral Ischemia and Oxygen-Glucose Deprivation.
Deletion of TRPC6 Attenuates NMDA Receptor-Mediated Ca(2+) Entry and Ca(2+)-Induced Neurotoxicity Following Cerebral Ischemia and Oxygen-Glucose Deprivation.
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DOI：
10.3389/fnins.2017.00138
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发表时间：
2017
影响因子：
4.3
通讯作者：
Cheng Z
中科院分区：
文献类型：
--
作者：
Chen J;Li Z;Hatcher JT;Chen QH;Chen L;Wurster RD;Chan SL;Cheng Z
瞬时受体电位规范6 （TRPC6）通道可渗透Na+和Ca2+，在大脑中广泛表达。本研究探讨了TRPC6在缺血/再灌注（I/R）和氧糖剥夺（OGD）后的作用。我们发现，TRPC6在野生型（WT）小鼠I/R后皮质神经元和OGD原代神经元中的表达增加，TRPC6的缺失减少了I/R诱导的小鼠脑梗死和OGD /神经毒素诱导的神经元死亡。使用活细胞成像检查细胞内Ca2+水平（[Ca2+]i），我们发现与未治疗对照相比，OGD诱导谷氨酸诱发的Ca2+内流显著增加，并且这种增加通过TRPC6缺失而减少。与AdCMV-GFP对照相比，使用AdCMV-TRPC6-GFP感染增强WT神经元中TRPC6表达的谷氨酸增加了[Ca2+]i。MK801抑制n -甲基-d-天冬氨酸受体（NMDAR）降低TRPC6感染细胞中[Ca2+]i的依赖性增加，表明这种Ca2+内流依赖于NMDAR。此外，通过阻断Na+进入TRPC6感染细胞，TRPC6依赖性Ca2+内流被减弱。最后，在电压依赖性Na+通道阻滞剂河蟹毒素（TTX）和dl-α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）阻滞剂CNQX的存在下，ogd增强的Ca2+内流减少，但未完全阻断。总之，我们得出结论，I/ r诱导的脑损伤部分是由于皮质神经元中TRPC6的上调。我们假设TRPC6在I/R后的过表达可能部分通过TRPC6依赖的Na+进入激活NMDAR，从而导致破坏性的Ca2+过载而诱导神经元死亡。这些发现可能为未来干预中风引起的脑损伤提供一个潜在的目标。
Transient receptor potential canonical 6 (TRPC6) channels are permeable to Na+ and Ca2+ and are widely expressed in the brain. In this study, the role of TRPC6 was investigated following ischemia/reperfusion (I/R) and oxygen-glucose deprivation (OGD). We found that TRPC6 expression was increased in wild-type (WT) mice cortical neurons following I/R and in primary neurons with OGD, and that deletion of TRPC6 reduced the I/R-induced brain infarct in mice and the OGD- /neurotoxin-induced neuronal death. Using live-cell imaging to examine intracellular Ca2+ levels ([Ca2+]i), we found that OGD induced a significant higher increase in glutamate-evoked Ca2+ influx compared to untreated control and such an increase was reduced by TRPC6 deletion. Enhancement of TRPC6 expression using AdCMV-TRPC6-GFP infection in WT neurons increased [Ca2+]i in response to glutamate application compared to AdCMV-GFP control. Inhibition of N-methyl-d-aspartic acid receptor (NMDAR) with MK801 decreased TRPC6-dependent increase of [Ca2+]i in TRPC6 infected cells, indicating that such a Ca2+ influx was NMDAR dependent. Furthermore, TRPC6-dependent Ca2+ influx was blunted by blockade of Na+ entry in TRPC6 infected cells. Finally, OGD-enhanced Ca2+ influx was reduced, but not completely blocked, in the presence of voltage-dependent Na+ channel blocker tetrodotoxin (TTX) and dl-α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) blocker CNQX. Altogether, we concluded that I/R-induced brain damage was, in part, due to upregulation of TRPC6 in cortical neurons. We postulate that overexpression of TRPC6 following I/R may induce neuronal death partially through TRPC6-dependent Na+ entry which activated NMDAR, thus leading to a damaging Ca2+ overload. These findings may provide a potential target for future intervention in stroke-induced brain damage.