Activation of autophagic flux and the Nrf2/ARE signaling pathway by hydrogen sulfide protects against acrylonitrile-induced neurotoxicity in primary rat astrocytes
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Hydrogen sulfide (H2S), the third gasotransmitter, has been shown to act as a neuroprotective factor in numerous pathological processes; however, its underlying mechanism(s) of action remain unclear. It is widely accepted that activation of moderate autophagy and the Nrf2/ARE signaling pathway play important roles in the biological self-defense systems. In the present study, we investigated whether exogenous H2S protects against the cytotoxicity of acrylonitrile (AN), a neurotoxin, in primary rat astrocytes. We found that pretreatment for 1 h with sodium hydrosulfide (NaHS), a donor of H2S (200–800 µM), significantly attenuated the AN-induced decrease in cell viability, increase in lactate dehydrogenase release and morphological changes. Furthermore, NaHS significantly attenuated AN-induced oxidative stress by reducing reactive oxygen species (ROS) levels and increasing glutathione (GSH) concentration. Moreover, NaHS activated the autophagic flux, detectable as a change in autophagy-related proteins (Beclin-1, Atg5 and p62), the formation of acidic vesicular organelles and LC3B aggregation, confirmed by adenoviral expression of mRFP–GFP–LC3. Additionally, NaHS stimulated translocation of Nrf2 into the nucleus and increased expression of heme oxygenase-1 and γ-glutamylcysteine synthetase, downstream targets of Nrf2. Notably, the autophagy inhibitor 3-methyladenine and Beclin-1, or Nrf2-targeted siRNA, significantly attenuated the neuroprotective effects of NaHS against AN-induced neurotoxicity. In conclusion, we identified a crucial role of autophagy and the Nrf2/ARE signaling pathway in H2S-mediated neuroprotection against AN-induced toxicity in primary rat astrocytes. Our findings provide novel insights into the mechanisms of H2S-mediated neuroprotection, and suggest that H2S-based donors may serve as potential new candidate drugs to treat AN-induced neurotoxicity.
KeywordsHydrogen sulfide Acrylonitrile Astrocyte Autophagy Nrf2 Oxidative stress
This work was partly supported in part by the Natural Science Foundation of China (Nos. 30872139, 81273124, 81302459) and by grants from the National Institute of Environmental Health Sciences (NIEHS R01ES07331, NIEHS R01ES10563 and NIEHS R01ES020852). We thank Barry Patel, PhD, from Liwen Bianji, Edanz Group China (http://www.liwenbianji.cn/ac), for editing the English text of a draft of this manuscript.
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Conflict of interest
The authors declare that there is no conflict of interest regarding the publication of this paper.
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