IL-1β dominates the promucin secretory cytokine profile in cystic fibrosis
Gang Chen, … , Wanda K. O’Neal, Richard C. Boucher
Gang Chen, … , Wanda K. O’Neal, Richard C. Boucher
Published September 16, 2019
Citation Information: J Clin Invest. 2019;129(10):4433-4450. https://doi.org/10.1172/JCI125669.
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Research Article Pulmonology

IL-1β dominates the promucin secretory cytokine profile in cystic fibrosis

Abstract

Cystic fibrosis (CF) lung disease is characterized by early and persistent mucus accumulation and neutrophilic inflammation in the distal airways. Identification of the factors in CF mucopurulent secretions that perpetuate CF mucoinflammation may provide strategies for novel CF pharmacotherapies. We show that IL-1β, with IL-1α, dominated the mucin prosecretory activities of supernatants of airway mucopurulent secretions (SAMS). Like SAMS, IL-1β alone induced MUC5B and MUC5AC protein secretion and mucus hyperconcentration in CF human bronchial epithelial (HBE) cells. Mechanistically, IL-1β induced the sterile α motif–pointed domain containing ETS transcription factor (SPDEF) and downstream endoplasmic reticulum to nucleus signaling 2 (ERN2) to upregulate mucin gene expression. Increased mRNA levels of IL1B, SPDEF, and ERN2 were associated with increased MUC5B and MUC5AC expression in the distal airways of excised CF lungs. Administration of an IL-1 receptor antagonist (IL-1Ra) blocked SAMS-induced expression of mucins and proinflammatory mediators in CF HBE cells. In conclusion, IL-1α and IL-1β are upstream components of a signaling pathway, including IL-1R1 and downstream SPDEF and ERN2, that generate a positive feedback cycle capable of producing persistent mucus hyperconcentration and IL-1α and/or IL-1β–mediated neutrophilic inflammation in the absence of infection in CF airways. Targeting this pathway therapeutically may ameliorate mucus obstruction and inflammation-induced structural damage in young CF children.

Authors

Gang Chen, Ling Sun, Takafumi Kato, Kenichi Okuda, Mary B. Martino, Aiman Abzhanova, Jennifer M. Lin, Rodney C. Gilmore, Bethany D. Batson, Yvonne K. O’Neal, Allison S. Volmer, Hong Dang, Yangmei Deng, Scott H. Randell, Brian Button, Alessandra Livraghi-Butrico, Mehmet Kesimer, Carla M.P. Ribeiro, Wanda K. O’Neal, Richard C. Boucher

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Figure 1

Mucin secretagogue activity of SAMS is mediated by IL-1α and/or IL-1β via IL-1R1.

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Mucin secretagogue activity of SAMS is mediated by IL-1α and/or IL-1β vi...
(A) Expression of MUC5B and MUC5AC mRNAs in non-CF HBE cells as determined by TaqMan assays after exposure to control (PBS), IL-1α, IL-1β, IL-13, or SAMS of CF lung for 5 days. IL-1α, IL-1β, and IL-13 were administered at 10 ng/ml in ALI media from basolateral side of the cells. Undiluted SAMS (50 μl) was administered to the apical surface of HBE cells, where it was maintained until the cells were utilized for assays. Scatter plots present mean ± SEM, with 1 culture of HBE cells obtained from 14 non-CF donors for each treatment condition. Data were analyzed with 1-way ANOVA followed by Dunnett’s test. (B) IL-1α and IL-1β protein concentration in SAMS was determined by ELISA. SAMS was collected from 8 CF lungs. Scatter plot presents mean ± SEM. (C) Non-CF HBE cells were infected with lentiviruses expressing EGFP (control) or IL-1R1 CRISPR guide RNA and Cas9 protein. After ALI was cultured for 4 weeks, CRISPR/Cas9 targeted cells were treated with vehicle control (PBS) or SAMS for 3 days. MUC5B, MUC5AC, SPDEF, and IL8 mRNAs in HBE cells were quantitatively measured by TaqMan assays. Scatter plots present mean ± SD. Data were derived from HBE cells from n = 6 non-CF donors analyzed with 2-tailed paired t test. *P < 0.05; **P < 0.01; ***P < 0.001. (D) Histological changes of HBE cells after cytokine treatment are shown by H&E staining. Goblet cell differentiation and mucus production are shown by AB-PAS staining. Expression of MUC5B and MUC5AC protein is demonstrated by immunohistochemical staining. Micrographs present non-CF HBE cells of 3 donors. Ψ, mucus layer; *, epithelial cell layer. Scale bar: 20 μm.