Broad-spectrum effects of 4-aminopyridine to modulate amyloid β1-42-induced cell signaling and functional responses in human microglia
Broad-spectrum effects of 4-aminopyridine to modulate amyloid β1-42-induced cell signaling and functional responses in human microglia
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DOI：
10.1523/jneurosci.2490-06.2006
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发表时间：
2006-11-08
影响因子：
5.3
通讯作者：
McLarnon, James G.
中科院分区：
文献类型：
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作者：
Franciosi, Sonia;Ryu, Jae K.;McLarnon, James G.
我们研究了非选择性K+通道阻滞剂4-氨基吡啶（4-AP）对淀粉样蛋白β (A β(1-42))诱导的人小胶质信号通路和功能过程的调节作用。全细胞膜片钳研究表明，A β (1-42) （5 μ M）急性应用于人小胶质细胞导致4- ap敏感的，非失活的向外整流K+电流（I-K）的快速表达。细胞内应用GTP的不可水解类似物GTP γ S，诱导向外的K+电流，其性质与A β(1-42)诱导的IK相似，包括对4-AP的敏感性（IC50 = 5 mM）。逆转录酶- pcr显示a β(1-42)处理的小胶质细胞中延迟整流Kv3.1通道的快速表达。β(1-42)肽也引起[Ca2+] (i)（细胞内钙）水平缓慢的进行性增加，这部分被4-AP阻断。人小胶质细胞长期暴露于A β(1-42)导致p38丝裂原活化蛋白激酶和核因子κ B的表达增强，而这些因子被4-AP抑制。A β(1-42)还诱导了促炎细胞因子白介素(IL)-1 β、IL-6、肿瘤坏死因子α、趋化因子IL-8和环氧化酶- 2的表达和产生；4-AP能有效减少所有这些促炎介质。此外，A β(1-42)处理的小胶质细胞上清液对培养的大鼠海马神经元的毒性降低，如果4-AP与肽一起加入。在体内，向大鼠海马注射A β(1-42)可诱导神经元损伤并增加小胶质细胞的激活。每天给药1 mg/kg 4-AP可抑制小胶质细胞的激活并具有神经保护作用。总体结果表明，4-AP调节A β(1-42)诱导的IK（候选通道Kv3.1）和人小胶质细胞内信号通路可以作为阿尔茨海默病病理中神经保护的治疗策略。
We investigated the modulating actions of the nonselective K+ channel blocker 4-aminopyridine ( 4-AP) on amyloid beta( A beta(1-42))-induced human microglial signaling pathways and functional processes. Whole-cell patch-clamp studies showed acute application of A beta(1-42) ( 5 mu M) to human microglia led to rapid expression of a 4-AP-sensitive, non-inactivating outwardly rectifying K+ current ( I-K). Intracellular application of the nonhydrolyzable analog of GTP, GTP gamma S, induced an outward K+ current with similar properties to the A beta(1-42)-induced IK including sensitivity to 4-AP ( IC50 = 5 mM). Reverse transcriptase-PCR showed a rapid expression of a delayed rectifier Kv3.1 channel in A beta(1-42)-treated microglia. A beta(1-42) peptide also caused a slow, progressive increase in levels of [ Ca2+] (i) ( intracellular calcium) that was partially blocked by 4-AP. Chronic exposure of human microglia to A beta(1-42) led to enhanced p38 mitogen-activated protein kinase and nuclear factor kappa B expression with factors inhibited by 4-AP. A beta(1-42) also induced the expression and production of the pro-inflammatory cytokines interleukin ( IL)-1 beta, IL-6, and tumor necrosis factor-alpha, the chemokine IL-8, and the enzyme cyclooxygenase- 2; 4-AP was effective in reducing all of these pro-inflammatory mediators. Additionally, toxicity of supernatant from A beta(1-42)-treated microglia on cultured rat hippocampal neurons was reduced if 4-AP was included with peptide. In vivo, injection of A beta(1-42) into rat hippocampus induced neuronal damage and increased microglial activation. Daily administration of 1 mg/kg 4-AP was found to suppress microglial activation and exhibited neuroprotection. The overall results suggest that 4-AP modulation of an A beta(1-42)-induced IK ( candidate channel Kv3.1) and intracellular signaling pathways in human microglia could serve as a therapeutic strategy for neuroprotection in Alzheimer's disease pathology.