Overexpression of AXL on macrophages associates with disease severity and recurrence in chronic rhinosinusitis with nasal polyps.

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is characterized by high tissue heterogeneity and risk of postoperative recurrence, but the underlying mechanisms are poorly elucidated. This study aims to explore the expressions of AXL on macrophages and their roles in the pathogenesis of CRSwNP, and evaluate their associations with disease severity and recurrence.

METHODS

Healthy controls (HCs), chronic rhinosinusitis without nasal polyps (CRSsNP) and CRSwNP patients were recruited in this study. Protein and mRNA levels of AXL and macrophage markers were detected in tissue samples, and their relationships with clinical variables and risk of postoperative recurrence were assessed. Immunofluorescence staining was conducted to confirm the location of AXL and its co-expression with macrophages. Regulated AXL in THP-1 and peripheral blood mononuclear cells (PBMC)-derived macrophages, and evaluated their polarization and cytokine secretion.

RESULTS

We found that AXL was enhanced in the mucosa and serum samples of CRSwNP patients, especially in recurrent cases. Tissue AXL levels were positively correlated with peripheral eosinophil count and percentage, Lund-Mackay score, Lund-Kennedy score, and macrophage M2 markers levels. Immunofluorescence staining results demonstrated that AXL was augmented and predominantly expressed on M2 macrophages in the tissues of CRSwNP, particularly in recurrent cases. In vitro experiment, overexpression of AXL promoted the M2 polarization of THP-1 and PBMC-derived macrophages, and facilitated the production of TGF-β1 and CCL-24.

CONCLUSIONS

AXL driving the M2 macrophage polarization exacerbated the disease severity and contributed to the postoperative recurrence in CRSwNP patients. Our findings supported AXL-targeted prevention and treatment of recurrent CRSwNP.