Synaptic NMDA Receptor Activation Stimulates α-Secretase Amyloid Precursor Protein Processing and Inhibits Amyloid-β Production
Synaptic NMDA Receptor Activation Stimulates α-Secretase Amyloid Precursor Protein Processing and Inhibits Amyloid-β Production
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DOI：
10.1523/jneurosci.6017-08.2009
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发表时间：
2009-04-08
影响因子：
5.3
通讯作者：
Perkinton, Michael S.
中科院分区：
文献类型：
--
作者：
Hoey, Sarah E.;Williams, Robert J.;Perkinton, Michael S.
改变的淀粉样前体蛋白（APP）加工导致A β的产生和寡聚化增加，可能有助于阿尔茨海默病（AD）。了解APP加工在生理条件下如何调节可能为AD发病机制提供新的见解。最近的报道表明，兴奋性神经活动调节APP代谢和A β水平，尽管对所涉及的分子机制的理解是不完整的。我们研究了NMDA受体活性是否调节原代培养的皮层神经元APP代谢。我们报告说，一个池的APP定位于皮层神经元的突触后区室，并观察到部分重叠的APP与NR 1和PSD-95。NMDA受体刺激增加非淀粉样α分泌酶介导的APP加工，如谷氨酸或NMDA处理后细胞α-C-末端片段（C83）水平增加2.5倍所测量的。这种增加被NMDA受体拮抗剂D-AP 5和MK 801阻断，但不被AMPA受体拮抗剂CNQX或L-型钙通道阻滞剂硝苯地平阻断，被细胞外钙螯合阻止，并被α-分泌酶抑制剂TAPI-1阻断。皮层神经元与荷包牡丹碱和4-AP，刺激谷氨酸释放和激活突触NMDA受体的共治疗，诱发了MK 801敏感的C83水平的增加。此外，NMDA受体刺激引起的神经元培养基中检测到的可溶性APP的量的两倍增加。最后，NMDA受体活性抑制由β-γ-分泌酶介导的APP-Gal 4融合蛋白裂解诱导的A β 1-40释放和Gal 4依赖性荧光素酶活性。总之，这些数据表明，通过突触NMDA受体的钙内流促进非淀粉样蛋白α分泌酶介导的APP加工。
Altered amyloid precursor protein (APP) processing leading to increased production and oligomerization of A beta may contribute to Alzheimer's disease ( AD). Understanding how APP processing is regulated under physiological conditions may provide new insights into AD pathogenesis. Recent reports demonstrate that excitatory neural activity regulates APP metabolism and A beta levels, although understanding of the molecular mechanisms involved is incomplete. We have investigated whether NMDA receptor activity regulates APP metabolism in primary cultured cortical neurons. We report that a pool of APP is localized to the postsynaptic compartment in cortical neurons and observed partial overlap of APP with both NR1 and PSD-95. NMDA receptor stimulation increased nonamyloidogenic alpha-secretase-mediated APP processing, as measured by a 2.5-fold increase in cellular alpha-C-terminal fragment (C83) levels after glutamate or NMDA treatment. This increase was blocked by the NMDA receptor antagonists D-AP5 and MK801 but not by the AMPA receptor antagonist CNQX or the L-type calcium channel blocker nifedipine, was prevented by chelation of extracellular calcium, and was blocked by the alpha-secretase inhibitor TAPI-1. Cotreatment of cortical neurons with bicuculline and 4-AP, which stimulates glutamate release and activates synaptic NMDA receptors, evoked an MK801-sensitive increase in C83 levels. Furthermore, NMDA receptor stimulation caused a twofold increase in the amount of soluble APP detected in the neuronal culture medium. Finally, NMDA receptor activity inhibited both A beta 1-40 release and Gal4-dependent luciferase activity induced by beta-gamma-secretase-mediated cleavage of an APP-Gal4 fusion protein. Altogether, these data suggest that calcium influx through synaptic NMDA receptors promotes nonamyloidogenic alpha-secretase-mediated APP processing.