Edaravone-Dexborneol slows down pathological progression and cognitive decline via inhibiting S100A9 in APPswe/PS1dE9 mice.

Background: Edaravone-Dexborneol (EDB) presents therapeutic effects due to its anti-inflammatory, antioxidant and anti-apoptotic properties, and has been widely used in ischemic stroke. However, the detailed efficacy and potential target of EDB in Alzheimer's disease (AD) are still elusive.

Methods: Male APPswe/PS1dE9 mice were administered with EDB intraperitoneally from 3.5 to 8 months of age. The cognition of mice was assessed by behavioral tests. Synaptic alternations in the hippocampus were detected by electrophysiology and Golgi staining. β-amyloid (Aβ) pathology was mainly observed by immunofluorescence. Oxidative stress-related indicators were evaluated by dedicated kits, while quantitative PCR and ELISA were used to detect pro-inflammatory factors. Proteomics analysis further identified the potential target of EDB.

Results: EDB was capable of delaying the cognitive decline and ameliorating the synaptic loss in APPswe/PS1dE9 mice. In addition to the anti-inflammation and anti-oxidation effects, EDB treatment mightily ablated the Aβ plaque by promoting microglial phagocytosis. Particularly, we first discovered that EDB could directly bind to S100A9, a pathological molecule that aggravates Aβ pathology and induces oxidative stress and neuroinflammation. EDB inhibited the expression, functional threonine phosphorylation and self-assembly of S100A9.

Conclusion: Our results indicate that EDB can improve cognitive function and slow down AD progression, and it may serve as a potential agent for AD and other S100A9-related diseases.