Downregulation and Aberrant Localization of Forkhead Box J1 in Allergic Nasal Mucosa

Abstract

Background: Forkhead box J1 (FOXJ1) plays pivotal roles in motile cilia formation. However, it remains unclear whether abnormal expression or localization of FOXJ1 in nasal mucosa tissues is associated with allergic rhinitis (AR), in which impaired mucociliary clearance is implicated.

Objective: We sought to investigate the expression and localization of FOXJ1 in inferior turbinate from patients with AR and controls.

Methods: We assayed mRNA levels of FOXJ1, DNAI1, DNALI1, and DNAH9 by using whole-genome expression array and quantitative real-time polymerase chain reaction. We elucidated the localization of FOXJ1 by using immunofluorescence assays in paraffin sections and primary single cells. Four patterns of FOXJ1 localization (normal, N; intermediate, I; mislocalization, M; absence, A) were defined. We developed a semiquantitative scoring system to elucidate their localization in 5 areas per paraffin section, with individual sections being assigned a score between 0 and 2.

Results: The mRNA levels of FOXJ1, DNAI1, DNALI1, and DNAH9 were significantly reduced in patients with AR compared with controls (all p < 0.05). The median (1st and 3rd quartile) of the FOXJ1 score was 0.4 (0.0 and 0.85) in patients with AR, and 0.2 (0.0 and 0.4) in controls (p < 0.05). For primary cytospin samples, the mean percentages of FOXJ1 localization patterns N, I, M, and A were 46.7, 10.0, 30.0, and 26.7% in patients with AR, and 82.5, 5.0, 5.0, and 7.5% in controls, respectively (p < 0.05).

Conclusion: Downregulation and aberrant localization of FOXJ1 may be crucial characteristics of the allergic nasal mucosa.

Keywords: Allergic rhinitis; Cilia; Forkhead box J1; Localization; Microarray.