ABSTRACT
BACKGROUND: Early brain injury (EBI) is closely associated with poor prognosis in patients with subarachnoid haemorrhage (SAH), with autophagy playing a pivotal role in EBI. However, research has shown that the stimulator of interferon genes (STING) pathway impacts autophagic flux. While the regulatory impact of neuritin on EBI and autophagic flux has been established previously, the underlying mechanism remains unclear. This study aimed to determine the role of the cGAS-STING pathway in neuritin-mediated regulation of autophagic flux following SAH. METHODS: A SAH model was established in male Sprague-Dawley rats via intravascular perforation. Neuritin overexpressions using adeno-associated virus, the STING antagonist "C-176," and the activator, "CMA," were determined to investigate the cGAS-STING pathway's influence on autophagic flux and brain injury post-SAH, along with the neuritin's regulatory effect on STING. In this study, SAH grade, neurological score, haematoxylin and eosin (H&E) staining, brain water content (BWC), sandwich enzyme-linked immunosorbent assay, Evans blue staining, immunofluorescence staining, western blot analysis, and transmission electron microscopy (TEM) were examined. RESULTS: Neuritin overexpression significantly ameliorated neurobehavioural scores, blood-brain barrier injury, brain oedema, and impaired autophagic flux in SAH-induced rats. STING expression remarkably increased post-SAH. C-176 and CMA mitigated and aggravated autophagic flux injury and brain injury, respectively, while inhibiting and enhancing STING, respectively. Particularly, CMA treatment nullified the protective effects of neuritin against autophagic flux and mitigated brain injury. CONCLUSION: Neuritin alleviated EBI by restoring impaired autophagic flux after SAH through the regulation of the cGAS-STING pathway.
Subject(s)
Autophagy , Brain Injuries , Membrane Proteins , Rats, Sprague-Dawley , Signal Transduction , Subarachnoid Hemorrhage , Animals , Autophagy/drug effects , Autophagy/physiology , Male , Subarachnoid Hemorrhage/metabolism , Subarachnoid Hemorrhage/complications , Rats , Signal Transduction/drug effects , Signal Transduction/physiology , Brain Injuries/metabolism , Membrane Proteins/metabolism , Neuropeptides/metabolism , GPI-Linked Proteins/metabolism , Disease Models, AnimalABSTRACT
OBJECTIVES: This study explored the anti-inflammatory, anti-neuronal apoptosis, and neuroprotective effects of Neuritin in rat models of acute ischemia stroke (AIS). METHODS: AIS was induced in male Sprague Dawley rats by middle cerebral artery occlusion (MCAO). Rats were divided into sham, MCAO, MCAO+neuritin, MCAO + neuritin + PBS, MCAO + neuritin+MCC950, and MCAO + neuritin + MSU groups. Neurological score assessment, brain water content measurement, HE staining, TTC staining, TUNEL staining, ELISA, and Western blot were performed. RESULTS: Neuritin significantly improved the neurobehavioral score, infarct size, brain water content, apoptosis, and neuroinflammatory response compared with the MCAO and MCAO + PBS groups within 24 h after AIS. Moreover, Neuritin inhibited the protein expression of NLRP3 inflammasome, and reduced the expression of IL-18 and IL-1B, thereby reducing the inflammatory response. Meanwhile, the neuroprotection, anti-inflammation, and anti-apoptosis effects of Neuritin were enhanced by MCC950 but partly counteracted by MSU. CONCLUSION: Neuritin may reduce brain injury after AIS by inhibiting the expression of NLRP3 inflammasome and then inhibiting the inflammatory response.
