Shikonin attenuates cerebral ischemia/reperfusion injury via inhibiting NOD2/RIP2/NF-κB-mediated microglia polarization and neuroinflammation

  • J Stroke Cerebrovasc Dis. 2024 Mar 26;33(6):107689. doi: 10.1016/j.jstrokecerebrovasdis.2024.107689.
Ya Yang  1 ,  Yuxiang Fei  2 ,  Xuejiao Xu  3 ,  Jun Yao  4 ,  Jianing Wang  5 ,  Chao Liu  2 ,  Haiyan Ding  6
Affiliations
  • 1. College of Pharmacy, Xinjiang Medical University, No. 567 North Shangde Road, Urumqi, Xinjiang 830017, PR China.
  • 2. Department of Pharmacy, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, PR China; School of Basic Medicine & Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, PR China.
  • 3. School of Basic Medicine & Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, PR China.
  • 4. College of Pharmacy, Xinjiang Medical University, No. 567 North Shangde Road, Urumqi, Xinjiang 830017, PR China; Xinjiang Key Laboratory of Natural Medicines Active Components and Drug Release Technology, Urumqi, Xinjiang 830017, PR China.
  • 5. Department of Pharmacy, The Affiliated Jiangning Hospital with Nanjing Medical University, Nanjing, Jiangsu 211100, PR China.
  • 6. College of Pharmacy, Xinjiang Medical University, No. 567 North Shangde Road, Urumqi, Xinjiang 830017, PR China; Xinjiang Key Laboratory of Natural Medicines Active Components and Drug Release Technology, Urumqi, Xinjiang 830017, PR China. Electronic address: [email protected].
PMID: 38527567 DOI: 10.1016/j.jstrokecerebrovasdis.2024.107689
Abstract

Objectives: Microglia-mediated neuroinflammation plays a crucial role in the pathophysiological process of multiple neurological disorders such as ischemic stroke, which still lacks effective therapeutic agents. Shikonin possesses anti-inflammatory and neuroprotective properties. However, its underlying mechanism remains elusive. This study aimed to investigate whether Shikonin confers protection against cerebral ischemia/reperfusion (I/R) injury by modulating microglial polarization and elucidate the associated mechanisms.

Methods: This study employed an oxygen-glucose deprivation and reoxygenation (OGD/R) BV2 microglial cellular model and a middle cerebral artery occlusion/reperfusion (MCAO/R) animal model to investigate the protection and underlying mechanism of Shikonin against ischemic stroke.

Results: The results demonstrated that Shikonin treatment significantly reduced brain infarction volume and improved neurological function in MCAO/R rats. Simultaneously, Shikonin treatment significantly reduced microglial proinflammatory phenotype and levels of proinflammatory markers (inducible-NO synthase (iNOS), tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and IL-6), increased microglial anti-inflammatory phenotype and levels of anti-inflammatory markers (Arginase-1 (Arg1), transforming growth factor-beta (TGF-β), and IL-10), reversed the expression of Nucleotide-binding oligomerization domain 2 (NOD2) and phosphorylation receptor interacting protein 2 (p-RIP2), and suppressed nuclear factor kappa-B (NF-κB) signaling activation in the ischemic penumbra regions. These effects of Shikonin were further corroborated in OGD/R-treated BV2 cells. Furthermore, overexpression of NOD2 markedly attenuated the neuroprotective effects of Shikonin treatment in MCAO/R rats. NOD2 overexpression also attenuated the regulatory effects of Shikonin on neuroinflammation, microglial polarization, and NF-κB signaling activation.

Conclusion: This study illustrates that Shikonin mitigates inflammation mediated by microglial proinflammatory polarization by inhibiting the NOD2/RIP2/NF-κB signaling pathway, thereby exerting a protective role. The findings uncover a potential molecular mechanism for Shikonin in treating ischemic stroke.

Keywords
Cerebral ischemia reperfusion injury; NOD2/RIP2/NF-κB signaling; Neuroinflammation; Shikonin; microglia polarization.
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