CDH11 Contributes to Airway Neutrophilic Inflammation in Severe Asthma via FGFR1

Cadherin-11 (CDH11), a specialized cell-cell adhesion protein, plays an essential role in tissue injury, inflammation and repair. This study aimed to investigate the role of CDH11 in severe asthma. Bronchial biopsy specimens were obtained from healthy subjects and patients with severe asthma. Two murine models of severe asthma were established using either TDI (toluene diisocyanate) or OVA (ovalbumin)/CFA (complete Freund's adjuvants). A selective CDH11 antagonist SD133 (100 mg/kg) was given to allergen-exposed mice after airway challenge. The effects of recombinant CDH11 were also tested in vivo, and FGFR1 inhibition was used to explore a possible mechanism for CDH11-induced inflammatory responses in the lung. We detected upregulated expression of CDH11 in the airway mucosa of severe asthma patients when compared with the healthy control. In the OVA/CFA-induced model, though CDH11 expression in the lung remained unchanged, pharmacological antagonism of CDH11 with SD133 dramatically decreased airway neutrophil accumulation, as well as IL-6 production, but had no effect on eosinophilic infiltration, type 2 inflammation (IL-4 and IL-5) nor airway hyperresponsiveness. In the TDI model, pulmonary CDH11 expression was upregulated. Treatment with SD133 inhibited TDI-induced airway hyperresponsiveness and neutrophilic inflammation, decreased IL-6 and TNF-α production, with no effect on airway eosinophil counts and type 2 inflammatory cytokines. In addition, intratracheal instillation of recombinant CDH11 led to neutrophil recruitment in the lungs of mice, which could be attenuated by inhibition of FGFR1 signaling. CDH11 contributes to airway neutrophilic inflammation in severe asthma through the FGFR1 pathway.