Subneurotoxic copper(II)-induced NF-魏B-dependent microglial activation is associated with mitochondrial ROS

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• 作者：Zhuqin Hu¹ ; Fengxiang Yu¹ ; Ping Gong ; Yu Qiu ; Wei Zhou ; Yongyao Cui ; Juan Li ; ^{lijuanpharm@gmail.com" class="auth_mail} ; Hongzhuan Chen ; ^{yaoli@shsmu.edu.cn" class="auth_mail}
• 关键词：AD ; Alzheimer's disease ; PD ; Parkinson's disease ; A尾 ; amyloid-尾 ; NF-泻B ; nuclear factor-泻B ; ROS ; reactive oxygen species ; DPI ; diphenylene iodonium ; NAC ; N-acetyl-cysteine ; iNOS ; inducible nitric oxide synthase ; DMEM ; Dulbecco's modified Eagle's medium ; FCS ; fetal calf serum ; CCK-8 ; Cell Counting Kit-8 ; TNF-伪 ; tumor necrosis factor-伪 ; KRPG ; Krebs&ndash ; Ringer phosphate buffer with glucose ; TBST ; Tris-buffered saline with Tween 20 ; CM ; conditioned medium ; IKK-2 ; I魏B kinase-2
• 刊名：Toxicology and Applied Pharmacology
• 出版年：15 April, 2014
• 年：2014
• 卷：276
• 期：2
• 页码：95-103
• 全文大小：1021 K

文摘

Microglia-mediated neuroinflammation and the associated neuronal damage play critical roles in the pathogenesis of neurodegenerative disorders. Evidence shows an elevated concentration of extracellular copper(II) in the brains of these disorders, which may contribute to neuronal death through direct neurotoxicity. Here we explored whether extracellular copper(II) triggers microglial activation. Primary rat microglia and murine microglial cell line BV-2 cells were cultured and treated with copper(II). The content of tumor necrosis factor-伪 (TNF-伪) and nitric oxide in the medium was determined. Extracellular hydrogen peroxide was quantified by a fluorometric assay with Amplex Red. Mitochondrial superoxide was measured by MitoSOX oxidation. At subneurotoxic concentrations, copper(II) treatment induced a dose- and time-dependent release of TNF-伪 and nitric oxide from microglial cells, and caused an indirect, microglia-mediated neurotoxicity that was blocked by inhibition of TNF-伪 and nitric oxide production. Copper(II)-initiated microglial activation was accompanied with reduced I泻B-伪 expression as well as phosphorylation and translocation of nuclear factor-魏B (NF-魏B) p65 and was blocked by NF-魏B inhibitors (BAY11-7082 and SC-514). Moreover, copper(II) treatment evoked a rapid release of hydrogen peroxide from microglial cells, an effect that was not affected by NADPH oxidase inhibitors. N-acetyl-cysteine, a scavenger of reactive oxygen species (ROS), abrogated copper(II)-elicited microglial release of TNF-伪 and nitric oxide and subsequent neurotoxicity. Importantly, mitochondrial production of superoxide, paralleled to extracellular release of hydrogen peroxide, was induced after copper(II) stimulation. Our findings suggest that extracellular copper(II) at subneurotoxic concentrations could trigger NF-魏B-dependent microglial activation and subsequent neurotoxicity. NADPH oxidase-independent, mitochondria-derived ROS may be involved in this activation.