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J Neuroinflammation. 2016 Oct 3;13(1):258.

Upregulation of neuronal zinc finger protein A20 expression is required for electroacupuncture to attenuate the cerebral inflammatory injury mediated by the nuclear factor-kB signaling pathway in cerebral ischemia/reperfusion rats.

Zhan J1,2,3, Qin W4, Zhang Y1,2, Jiang J1,2, Ma H1,2, Li Q1,2, Luo Y5,6.

Author information

1
Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.
2
Chongqing Key Laboratory of Neurology, 1 Youyi Road, Yuzhong District, Chongqing, 400016, China.
3
Department of Neurology, The Affiliated Hospital of Zunyi Medical College, Zunyi, Guizhou Province, 563000, China.
4
Department of Integrated Chinese and Western Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.
5
Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China. luoyong1998@163.com.
6
Chongqing Key Laboratory of Neurology, 1 Youyi Road, Yuzhong District, Chongqing, 400016, China. luoyong1998@163.com.

Abstract

BACKGROUND:

Zinc finger protein A20 (tumor necrosis factor alpha-induced protein 3) functions as a potent negative feedback inhibitor of the nuclear factor-kB (NF-kB) signaling. It exerts these effects by interrupting the activation of IkB kinase beta (IKKβ), the most critical kinase in upstream of NF-kB, and thereby controlling inflammatory homeostasis. We reported previously that electroacupuncture (EA) could effectively suppress IKKβ activation. However, the mechanism underlying these effects was unclear. Therefore, the current study further explored the effects of EA on A20 expression in rat brain and investigated the possible mechanism of A20 in anti-neuroinflammation mediated by EA using transient middle cerebral artery occlusion (MCAO) rats.

METHODS:

Rats were treated with EA at the "Baihui (GV20)," "Hegu (L14)," and "Taichong (Liv3)" acupoints once a day starting 2 h after focal cerebral ischemia. The spatiotemporal expression of A20, neurobehavioral scores, infarction volumes, cytokine levels, glial cell activation, and the NF-kB signaling were assessed at the indicated time points. A20 gene interference (overexpression and silencing) was used to investigate the role of A20 in mediating the neuroprotective effects of EA and in regulating the interaction between neuronal and glial cells by suppressing neuronal NF-kB signaling during cerebral ischemia/reperfusion-induced neuroinflammation.

RESULTS:

EA treatment increased A20 expression with an earlier peak and longer lasting upregulation. The upregulated A20 protein was predominantly located in neurons in the cortical zone of the ischemia/reperfusion. Furthermore, neuronal A20 cell counts were positively correlated with neurobehavioral scores but negatively correlated with infarct volume, the accumulation of pro-inflammatory cytokines, and glial cell activation. Moreover, the effects of EA on improving the neurological outcome and suppressing neuroinflammation in the brain were reversed by A20 silencing. Finally, A20 silencing also suppressed the ability of EA to inhibit neuronal NF-kB signaling pathway.

CONCLUSIONS:

Ischemia/reperfusion cortical neurons in MCAO rats are the main cell types that express A20, and there is a correlation between A20 expression and the suppression of neuroinflammation and the resulting neuroprotective effects. EA upregulated neuronal A20 expression, which played an essential role in the anti-inflammatory effects of EA by suppressing the neuronal NF-kB signaling pathway in the brains of MCAO rats.

KEYWORDS:

Cerebral ischemia; Electroacupuncture; NF-kB signaling pathway; Neuroinflammation; Zinc finger protein A20

PMID:
27716383
PMCID:
PMC5048665
DOI:
10.1186/s12974-016-0731-3
[Indexed for MEDLINE]
Free PMC Article

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