Peripheral site acetylcholinesterase blockade induces RACK1 - Associated neuronal remodeling
Peripheral site acetylcholinesterase blockade induces RACK1 - Associated neuronal remodeling
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DOI：
10.1159/000101842
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发表时间：
2007-01-01
影响因子：
3
通讯作者：
Soreq, Hermona
中科院分区：
文献类型：
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作者：
Farchi, Noa;Ofek, Keren;Soreq, Hermona
背景资料：乙酰胆碱酯酶（AChE）的外周阴离子位点（PAS）阻断显著影响神经元的活性和细胞结构，但其机制尚不完全清楚。目的：我们希望说明PAS细胞外效应对特定的乙酰胆碱酯酶mRNA剪接变异体，描绘随之而来的细胞重塑事件，并探讨对RACKI相互作用的抑制作用。研究方法：本实验采用体外培养大鼠海马神经元，分别用AChE外周阴离子位点抑制剂BW 284 C51和非选择性AChE活性位点抑制剂毒扁豆碱处理，研究AChE mRNA表达和转运的神经元重构。结果如下：BW 284 C51诱导两种AChE剪接变体的过表达，但以反义抑制的方式促进通常罕见的ACH-R的神经炎易位和AChE-S mRNA的回缩。BW 284 C51进一步导致支架蛋白RACK 1（活化蛋白激酶P11的受体）表达的适度降低，随后RACK 1和AChE同源物neuroligin 1的神经突急剧收缩，但不是微管蛋白相关的MAP 2蛋白。伴随BW 284 C51的影响涉及Fyn激酶和谷氨酸受体NR 2B变体的膜插入的减少以及经处理的细胞的谷氨酸能活性受损。有趣的是，分子模拟表明，RACKI相互作用的AChE-R变体与Fyn结合的直接，非催化竞争可能参与其中。结论：我们的研究结果突出了复杂的神经元AChE-R/RACK 1的相互作用，并与外周部位AChE抑制剂诱导RACK 1介导的神经元重塑，促进抑制的多巴胺能神经传递的假设是一致的。
Background: Peripheral anionic site (PAS) blockade of acetylcholinesterase (AChE) notably affects neuronal activity and cyto-architecture, however, the mechanism(s) involved are incompletely understood. Objective: We wished to specify the PAS extracellular effects on specific AChE mRNA splice variants, delineate the consequent cellular remodeling events, and explore the inhibitory effects on interchanging RACKI interactions. Methods: We exposed rat hippocampal cultured neurons to BW284C51, the peripheral anionic site inhibitor of AChE, and to the non-selective AChE active site inhibitor, physostigmine for studying the neuronal remodeling of AChE mRNA expression and trafficking. Results: BW284C51 induced overexpression of both AChE splice variants, yet promoted neuritic translocation of the normally rare ACH-R, and retraction of AChE-S mRNA in an antisense-sup-pressible manner. BW284C51 further caused modest decreases in the expression of the scaffold protein RACK1 (receptor for activated protein kinase P11), followed by drastic neurite retraction of both RACK1 and the AChE homologue neuroligin1, but not the tubulin-associated MAP2 protein. Accompanying BW284C51 effects involved decreases in the Fyn kinase and membrane insertion of the glutamate receptor NR2B variant and impaired glutamatergic activities of treated cells. Intriguingly, molecular modeling suggested that direct, non-catalytic competition with Fyn binding by the RACKI-interacting AChE-R variant may be involved. Conclusions: Our findings highlight complex neuronal AChE-R/RACK1 interactions and are compatible with the hypothesis that peripheral site AChE inhibitors induce RACK1-mediated neuronal remodeling, promoting suppressed glutamatergic neurotransmission.