Format

Send to

Choose Destination
Chemosphere. 2019 Nov 27;244:125495. doi: 10.1016/j.chemosphere.2019.125495. [Epub ahead of print]

AMPK/p38/Nrf2 activation as a protective feedback to restrain oxidative stress and inflammation in microglia stimulated with sodium fluoride.

Author information

1
Zhengzhou Key Laboratory of Animal Nutrition Metabolic and Poisoning Diseases, College of Veterinary Medicine, Henan University of Animal Husbandry and Economy, Zhengzhou, Henan, 450000, People's Republic of China.
2
Zhengzhou Key Laboratory of Animal Nutrition Metabolic and Poisoning Diseases, College of Veterinary Medicine, Henan University of Animal Husbandry and Economy, Zhengzhou, Henan, 450000, People's Republic of China; Shanxi Key Laboratory of Ecological Animal Sciences and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China. Electronic address: wangjd53@outlook.com.
3
Zhengzhou Key Laboratory of Animal Nutrition Metabolic and Poisoning Diseases, College of Veterinary Medicine, Henan University of Animal Husbandry and Economy, Zhengzhou, Henan, 450000, People's Republic of China. Electronic address: dongmeishi126@126.com.

Abstract

Dysregulated activation of inflammation plays an important role in the development and progression of neuronal damage, and limiting the production of reactive oxygen species (ROS) can suppress the inflammatory signals. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a redox-sensing transcription factor that drives an adaptive cellular defense in response to oxidative stress. However, the implications of Nrf2 in sodium fluoride (NaF)-stimulated microglia and the underlying mechanisms remain obscure. In this study, we demonstrated that NaF activated the Nrf2 signaling and enhanced the downstream antioxidant protein levels, including heme oxygenase-1 and quinine oxidoreductase 1. NaF induced oxidative stress, as indicated by increased ROS level and malondialdehyde content, and reduced superoxide dismutase activity. Moreover, NaF promoted the nuclear translocation of NF-κB, thus increased the production of the pro-inflammatory cytokines tumor necrosis factor-α, interleukin (IL)-6, and IL-1β. However, these effects were relieved by overexpression of Nrf2. Meanwhile, knockdown of Nrf2 by shRNA exacerbated NaF-induced oxidative stress and inflammation in BV-2 cells and primary cultured microglia. Mechanistically, NaF-induced Nrf2 activation is AMPK/p38 dependent, as deletion of AMPK using siRNA blocked the activating effect of NaF on p38 and Nrf2. Notably, treatment of N-Acety-l-Cysteine attenuated AMPK/p38-dependent Nrf2 activation in microglia exposed to NaF. In conclusion, these data demonstrated for the first time that Nrf2 activation exerts a neuroprotective effect on NaF-stimulated redox imbalance and inflammation that is dependent on the AMPK/p38 pathway.

KEYWORDS:

AMPK; Fluoride; Inflammation; Microglia; Nrf2; Oxidative stress

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center