Fasudil improves neutrophilic asthma by influencing M1 macrophage polarization and the expression of the...

Neutrophilic asthma (NA), an asthma subtype characterized by neutrophil-predominant airway inflammation, lacks effective targeted therapies. Fasudil, with documented anti-oxidative and anti-inflammatory effects in airway models, was evaluated for its therapeutic efficacy and underlying mechanisms in an NA model. BALB/C mice were randomized into an NA group, a dexamethasone intervention group (DI, 1 mg/kg), and a Fasudil intervention group (FI, 40 mg/kg). Asthma was induced by intraperitoneal ovalbumin (OVA) sensitization and intranasal lipopolysaccharide (LPS) infusion, followed by OVA aerosol challenge. Dexamethasone or Fasudil was administered intraperitoneally 1 h before each aerosol exposure. Outcome assessments included behavioral stress responses, airway hyperresponsiveness (AHR), total and differential bronchoalveolar lavage fluid (BALF) cell counts, lung histopathology, and macrophage contents, inflammatory mediators and cytokine expression. Transcriptome sequencing with bioinformatic analysis was performed. Blood samples from NA patients were collected for clinical validation. Both dexamethasone and Fasudil significantly alleviated behavioral stress responses, improved asthma symptoms, and reduced levels of interleukin-6 (IL-6), IL-1β, tumor necrosis factor alpha (TNF-α), inducible nitric oxide synthase (iNOS), and IL-12. Additionally, treatment also decreased the expression of phosphorylated nuclear factor kappa B (p-NF-κB), toll-like receptor 2 (TLR-2) and ribosomal protein S3 (RPS3), as well as total BALF cells and neutrophil-to-macrophage ratios. Fasudil outperformed dexamethasone in relieving respiratory distress, inhibiting macrophage polarization, suppressing the NF-κB/TLR-2/RPS3 pathway, and improving AHR in a time-dependent manner. Key hub genes including ROCK2, S100A8, S100A9, Mmp9, and CXCL2 were identified to mediate Fasudil's anti-inflammatory effects. Clinical data showed elevated S100A8 and CXCL2 levels in NA patients, which positively correlated with sputum neutrophil percentages. Fasudil ameliorates NA via regulating M1 macrophage polarization, inhibiting the NF-κB/TLR-2/RPS3 pathway, and reducing pro-inflammatory cytokines, with S100A8/A9 and CXCL2 as potential biomarkers. These findings support Fasudil as a promising NA therapy, warranting further clinical translational research.