Upregulated expression of Notch1/4 - JAG-1/DLL-1 detected in allergic rhinitis

Abstract

Background: Allergic rhinitis (AR) is a chronic disease with high prevalence. There are currently many treatments available. However, despite an often good therapeutic response, many patients still report impairment in quality of life (QoL) during the pollen season. A skewed T helper (Th)2 polarization is a well-acknowledged pathologic feature of AR. In animal models, local notch signaling in peripheral tissue seems crucial for Th2 cell differentiation and the development of AR. However, the involvement of Notch signaling in Th2 cell differentiation and the development of AR in humans remains unknown. Hence, the present study investigated the human expression of Notch receptors on CD4⁺ T-cells in nasal mucosa and blood. Correspondingly Notch ligand expression was assessed on nasal epithelial cells and neutrophils.

Methodology: Nasal brush and blood samples from 18 patients with pollen-induced AR and 22 healthy controls were collected outside the pollen season. Notch 1-4 and Jagged-1,2 and Delta-like ligand 1,3-4 was analyzed using flow cytometry.

Results: The fraction of CD4⁺Notch1⁺ and CD4⁺Notch4⁺ T-cells was higher in AR patients than in healthy control patients. Further, the expression levels of the Notch ligands JAG-1 and DLL-1 were increased in nasal epithelial cells from AR patients compared to healthy control patients. In addition, AR patients displayed higher expression of JAG-1 on neutrophils both in the nasal mucosa and in peripheral blood.

Conclusion: The present study is the first to demonstrate increased activity in the Notch1/4 - JAG-1/DLL-1 pathways among allergic individuals. Further propagating the importance of Notch signalling in AR and blocking JAG-1 and DLL-1-induced Notch signalling by nasal epithelial cells and Neutrophils are potential targets to reduce allergic airway inflammation.

Keywords: Allergic rhinitis; Epithelial cells; Neutrophils; Notch; T-cells.

Fig. 1

Notch1-4 on T-cells in nasal mucosa and blood. A: Fraction of CD4 T-cells in nasal mucosa expressing Notch. B: Distribution of CCR5⁺, CRTH2⁺ and CD25⁺⁺CD127^low within blood-derived Notch-4⁺ respectively Notch-4⁻ CD4⁺ T-cells. C: Visualization of the flow cytometry analysis of Th1, Th2, and Treg from one healthy control patient. Allergic rhinitis (AR), healthy controls (HC). Horizontal lines represent the mean value and SD. p < 0.05=*, p < 0.01= **, p < 0.001= **

Fig. 2

Expression of Notch ligands on epithelial cells in the nasal mucosa. A: In epithelial cells, the median fluorescence intensity of JAG-1, JAG-2, DLL-1, and DLL-4 are displayed with violin plots; the horizontal line represents the median value. B: Fraction of epithelial cells expressing Notch ligands, the horizontal lines represent the mean value and SD. C: Flow cytometry analysis of Notch ligands, data from one healthy control (HC) patient and one allergic rhinitis (AR) the patient is visualized. Dotted line = FMO control, black line = HC patient, Filled grey = AR. Patients with AR, (n = 9), HC, (n = 11). p < 0.05= *, p < 0.01= **

Fig. 3

Notch ligands on neutrophils in nasal mucosa and blood. Median fluorescence intensity of JAG-1, JAG-2, DLL-1, and DLL-4 in A: Nasal mucosa-derived neutrophils and B: Blood-derived neutrophils are displayed with violin plots; the horizontal line represents the median value. Fraction of neutrophils expressing Notch ligands in B: Nasal mucosa and D: Blood, Horizontal lines represent the mean value and SD. E: Flow cytometry analysis of Notch ligands, data from one healthy control (HC) patient and one allergic rhinitis (AR) the patient is visualized. Dotted line = FMO control, black line = HC, Filled grey = AR. Patients with AR, (n = 9), HC, (n = 11). p < 0.05= *, p < 0.01= **