1. Academic Validation
  2. Neutrophil Extracellular Traps may be a Potential Target for Treating Early Brain Injury in Subarachnoid Hemorrhage

Neutrophil Extracellular Traps may be a Potential Target for Treating Early Brain Injury in Subarachnoid Hemorrhage

  • Transl Stroke Res. 2022 Feb;13(1):112-131. doi: 10.1007/s12975-021-00909-1.
Hanhai Zeng  # 1 Xiongjie Fu  # 1 Jing Cai  # 2 Chenjun Sun 3 Mengyan Yu 3 Yucong Peng 1 Jianfeng Zhuang 1 Jingyin Chen 1 Huaijun Chen 1 Qian Yu 1 Chaoran Xu 1 Hang Zhou 1 Yang Cao 1 Libin Hu 1 Jianru Li 1 Shenglong Cao 1 Chi Gu 1 Feng Yan 4 Gao Chen 5
Affiliations

Affiliations

  • 1 Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Jiefang Road 88th, Hangzhou, 310000, China.
  • 2 Neurosurgerical Intensive Care Unit, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.
  • 3 Zhejiang University School of Medicine, Hangzhou, China.
  • 4 Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Jiefang Road 88th, Hangzhou, 310000, China. fengyanzju@zju.edu.cn.
  • 5 Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Jiefang Road 88th, Hangzhou, 310000, China. d-chengao@zju.edu.cn.
  • # Contributed equally.
Abstract

Neuroinflammation is closely associated with poor prognosis in patients with subarachnoid hemorrhage (SAH). The purpose of this study was to investigate the role of neutrophil extracellular traps (NETs), which are important regulators of sterile inflammation, in SAH. In this study, markers of NET formation, quantified by the level of citrullinated histone H3 (CitH3), were significantly increased after SAH and correlated with SAH severity. CitH3 peaked at 12 h in peripheral blood and at 24 h in the brain. Administration of the peptidyl arginine deiminase 4 (PAD4) selective antagonist GSK484 substantially attenuated SAH-induced brain edema and neuronal injury. Moreover, the benefit of NET inhibition was also confirmed by DNAse I treatment and neutrophil depletion. Mechanistically, NETs markedly exacerbated microglial inflammation in vitro. NET formation aggravated neuroinflammation by promoting microglial activation and increased the levels of TNF-α, IL-1β, and IL-6, while inhibiting NETs demonstrated anti-inflammatory effects by decreasing the levels of these proinflammatory factors. Moreover, neurogenic pulmonary edema (NPE), a severe nonneurological complication after SAH, is associated with a high level of NET formation. However, GSK484 effectively inhibited the formation of NETs in the lungs of NPE mice, thereby preventing the diffusion of neutrophilic infiltration and attenuating the swelling of the alveolar interstitium. In conclusion, NETs promoted neuroinflammation after SAH, while pharmacological inhibition of PAD4-NETs could reduce the inflammatory damage caused by SAH. These results supported the idea that NETs might be potential therapeutic targets for SAH.

Keywords

Microglia; Neurogenic pulmonary edema; Neuroinflammation; Neutrophil extracellular traps; Subarachnoid hemorrhage.

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