Overexpression of the circadian gene Bmal1 regulates the Nrf2/HO-1 oxidative stress pathway to alleviate inflammation and apoptosis in PC12 cells following cerebral ischemia-reperfusion injury

Jun 17, 2025Medicine

Increased activity of the body clock gene Bmal1 may reduce cell damage and inflammation after brain blood flow injury by controlling the antioxidant system in nerve-like cells

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Abstract

Bmal1 overexpression significantly reduces apoptosis and inflammatory responses in PC12 cells after ischemia/reperfusion injury.

  • Following oxygen-glucose deprivation/reoxygenation (OGD/R), Bmal1 gene and protein expression levels decreased in PC12 cells.
  • Overexpression of Bmal1 led to increased levels of Bmal1 mRNA and protein, indicating successful transfection.
  • Bmal1 overexpression was associated with a down-regulation of pro-apoptotic proteins BCL2-Associated X and cysteine-dependent aspartate-directed protease 3.
  • An increase in the anti-apoptotic protein Bcl-2 was observed with Bmal1 overexpression, which may contribute to reduced apoptosis.
  • Bmal1 overexpression inhibited the release of inflammatory cytokines interleukin-6 and interleukin-1β following OGD/R.
  • Activation of the Nrf2/HO-1 oxidative stress signaling pathway was indicated by Bmal1 overexpression, leading to reduced intracellular reactive oxygen species.

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Key numbers

95%
Increase in Bmal1 Expression
Transfection efficiency of Bmal1 overexpression in PC12 cells.
Decreased
Decrease in Apoptosis Rate
Comparison of apoptosis rates between Bmal1 overexpression and model groups.
Significantly reduced
Reduction in Inflammatory Cytokines
Levels of IL-1β and IL-6 in the Bmal1 overexpression group vs. model group.

Full Text

What this is

  • This research investigates the role of the circadian gene Bmal1 in ().
  • Using PC12 cells, the study examines how Bmal1 overexpression affects oxidative stress, inflammation, and apoptosis.
  • Findings indicate that Bmal1 regulates the , offering potential therapeutic insights for .

Essence

  • Bmal1 overexpression in PC12 cells reduces inflammation and apoptosis after ischemia-reperfusion injury by activating the Nrf2/HO-1 oxidative stress pathway.

Key takeaways

  • Bmal1 gene expression decreases following oxygen-glucose deprivation/reoxygenation (OGD/R), indicating its potential role in cellular stress responses.
  • Overexpression of Bmal1 significantly reduces pro-apoptotic proteins Caspase-3 and Bax while increasing the antiapoptotic protein Bcl-2, leading to decreased apoptosis rates.
  • Bmal1 overexpression activates the , enhancing antioxidant enzyme activity and reducing reactive oxygen species (ROS) levels, thereby mitigating oxidative stress.

Caveats

  • Results from PC12 cells may not fully reflect in vivo conditions of , limiting generalizability.
  • The study's focus on Bmal1 may overlook other important signaling pathways and molecular interactions involved in .

Definitions

  • Cerebral ischemia-reperfusion injury (CIRI): A condition where blood supply restoration after ischemia leads to further brain damage due to oxidative stress and inflammation.
  • Nrf2/HO-1 pathway: A cellular signaling pathway that regulates oxidative stress responses and promotes the expression of antioxidant enzymes.

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