Human airway epithelial cells express a functional IL-5 receptor

Abstract

We found that HBEC expressed the IL-5 receptor, which triggered intracellular signaling and changed gene expression. This data indicate that in addition to targeting eosinophils, IL-5 and anti-IL-5 biologics may have a direct role on AEC.

Keywords: IL-5 receptor; RNA-sequencing; airway epithelial cells; gene expression; intracellular signaling.

Figure 1.. Human bronchial epithelial cells (HBEC) express the two subunits of the IL-5 receptor.

A and B. HBEC were either cultured undifferentiated as a monolayer (1 donor) or fully differentiated at an air liquid interface (ALI; 9 donors). A. IL5RA mRNA levels were determined by RT-qPCR, normalized to GUSB, and expressed as a fold difference compared to the monolayer. Dots identify fold difference for each individual culture. Mean Ct values are shown. B. CSF2RB mRNA levels. Analysis is identical to that for IL5RA mRNA in A. C and D. Differentiated HBEC in ALI cultures were treated with rh-IL-5 (10ng/mL) for 15 minutes. Western blots were performed to visualize IL5RA (C) and CSF2RB (D) proteins. Eosinophils were used as a positive control. Graphs represent ratios of IL5RA (n=3) and CSF2RB (n=6) to β-actin normalized to untreated HBEC (T0). E. In red, protein expression of the IL-5 receptor α-(IL5RA, upper panel) and β- (CSF2RB, lower panel) subunits in bronchial tissue from one lung donor as determined by immunofluorescence. In blue, DAPI (nuclei) staining.

Figure 2.. IL-5 receptor expressed by HEBC is functional.

A. B. and C. Differentiated HBEC at ALI were treated with rh-IL-5 (10ng/mL) for 15 and 60 minutes. Analyses of ERK, Akt and STAT5A phosphorylation in HBEC lysates from four different donors were performed by western blotting. For ERK and Akt, graphs indicate means ± SEM from four cultures. Data were analyzed by ANOVA followed by Holm-Sidak method (A) and ANOVA followed by Turkey test (B). C. Eosinophils (EOS) activated with rh-IL-5 were used as a positive control. D. HBEC from three different donors, were cultured at ALI and remained untreated (Mock) or were activated with rh-IL-5 (10ng/ml) for 24 h. RNA-sequencing was performed and a volcano plot demonstrating transcript levels increased (red) and decreased (blue) is shown.