Neuronal Loss of the Glutamate Transporter GLT-1 Promotes Excitotoxic Injury in the Hippocampus.
Neuronal Loss of the Glutamate Transporter GLT-1 Promotes Excitotoxic Injury in the Hippocampus.
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DOI：
10.3389/fncel.2021.788262
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发表时间：
2021
影响因子：
5.3
通讯作者：
Rosenberg PA
中科院分区：
文献类型：
--
作者：
Rimmele TS;Li S;Andersen JV;Westi EW;Rotenberg A;Wang J;Aldana BI;Selkoe DJ;Aoki CJ;Dulla CG;Rosenberg PA
GLT-1 是哺乳动物中枢神经系统中主要的谷氨酸转运蛋白，除星形胶质细胞外，还表达于使用谷氨酸作为神经递质的突触前末梢。人们普遍认为谷氨酸稳态主要由星形胶质细胞中表达的谷氨酸转运蛋白调节，而神经元中 GLT-1 的功能相对未被探索。我们生成了条件性 GLT-1 敲除 (KO) 小鼠系，以了解 GLT-1 的细胞特异性功能。我们发现，在 40 周时，海马 CA1 区记录的刺激诱发场细胞外突触后电位 (fEPSP) 在星形胶质细胞 GLT-1 KO 中正常，但在神经元 GLT-1 KO 中降低且经常缺失。在 20 周龄小鼠的切片中也观察到神经元 GLT-1 KO 中 fEPSP 生成失败，但与 10 周龄小鼠的切片不一致。使用基于细胞外 FRET 的谷氨酸传感器，我们发现神经元 GLT-1 KO 中刺激诱发的谷氨酸积累没有差异，这表明传输失败是突触后原因。我们假设兴奋性毒性是神经元 GLT-1 KO 切片功能恢复失败的原因。与这一假设一致，非竞争性 NMDA 受体拮抗剂 MK801，当在切片后的恢复期间存在于 ACSF 中时，促进 fEPSP 生成的完全恢复。 ACSF 中包含酶促谷氨酸清除系统可提供部分保护。兴奋性毒性可能是由于兴奋性氨基酸的过度释放或积累，或代谢扰动导致 NMDA 受体激活的脆弱性增加。先前的研究已经证明体内 synGLT-1 KO 中突触线粒体利用谷氨酸和天冬氨酸产生的缺陷，并且我们在切片制备中发现了类似代谢扰动的证据。此外，20-25周龄synGLT-1 KO小鼠的CA1区突触线粒体中线粒体嵴密度较高，表明通过提高线粒体效率来补偿轴突末端GLT-1的损失。这些数据表明，突触前末梢表达的GLT-1在兴奋性毒性脆弱性的调节中发挥重要作用，这种调节可能与谷氨酸能轴突末梢表达的GLT-1的代谢作用有关。
GLT-1, the major glutamate transporter in the mammalian central nervous system, is expressed in presynaptic terminals that use glutamate as a neurotransmitter, in addition to astrocytes. It is widely assumed that glutamate homeostasis is regulated primarily by glutamate transporters expressed in astrocytes, leaving the function of GLT-1 in neurons relatively unexplored. We generated conditional GLT-1 knockout (KO) mouse lines to understand the cell-specific functions of GLT-1. We found that stimulus-evoked field extracellular postsynaptic potentials (fEPSPs) recorded in the CA1 region of the hippocampus were normal in the astrocytic GLT-1 KO but were reduced and often absent in the neuronal GLT-1 KO at 40 weeks. The failure of fEPSP generation in the neuronal GLT-1 KO was also observed in slices from 20 weeks old mice but not consistently from 10 weeks old mice. Using an extracellular FRET-based glutamate sensor, we found no difference in stimulus-evoked glutamate accumulation in the neuronal GLT-1 KO, suggesting a postsynaptic cause of the transmission failure. We hypothesized that excitotoxicity underlies the failure of functional recovery of slices from the neuronal GLT-1 KO. Consistent with this hypothesis, the non-competitive NMDA receptor antagonist MK801, when present in the ACSF during the recovery period following cutting of slices, promoted full restoration of fEPSP generation. The inclusion of an enzymatic glutamate scavenging system in the ACSF conferred partial protection. Excitotoxicity might be due to excess release or accumulation of excitatory amino acids, or to metabolic perturbation resulting in increased vulnerability to NMDA receptor activation. Previous studies have demonstrated a defect in the utilization of glutamate by synaptic mitochondria and aspartate production in the synGLT-1 KO in vivo, and we found evidence for similar metabolic perturbations in the slice preparation. In addition, mitochondrial cristae density was higher in synaptic mitochondria in the CA1 region in 20–25 weeks old synGLT-1 KO mice in the CA1 region, suggesting compensation for loss of axon terminal GLT-1 by increased mitochondrial efficiency. These data suggest that GLT-1 expressed in presynaptic terminals serves an important role in the regulation of vulnerability to excitotoxicity, and this regulation may be related to the metabolic role of GLT-1 expressed in glutamatergic axon terminals.
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DOI：
10.1038/npp.2015.26
发表时间：
2015-06
期刊：
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
影响因子：
--
作者：
Aida T;Yoshida J;Nomura M;Tanimura A;Iino Y;Soma M;Bai N;Ito Y;Cui W;Aizawa H;Yanagisawa M;Nagai T;Takata N;Tanaka KF;Takayanagi R;Kano M;Götz M;Hirase H;Tanaka K
通讯作者：
Tanaka K
影响因子：
3.1
作者：
Andersen JV;Nissen JD;Christensen SK;Markussen KH;Waagepetersen HS
通讯作者：
Waagepetersen HS
影响因子：
3.4
作者：
Blitzblau, R;Gupta, S;Rosenberg, PA
通讯作者：
Rosenberg, PA
影响因子：
5.3
作者：
Chen, WZ;Mahadomrongkul, V;Rosenberg, PA
通讯作者：
Rosenberg, PA
影响因子：
5.8
作者：
Albuquerque, Edson X.;Schwarcz, Robert
通讯作者：
Schwarcz, Robert