Targeting IL-17A/glucocorticoid synergy to CSF3 expression in neutrophilic airway diseases
Suidong Ouyang, … , Andy C. Lui, Xiaoxia Li
Suidong Ouyang, … , Andy C. Lui, Xiaoxia Li
Published February 13, 2020
Citation Information: JCI Insight. 2020;5(3):e132836. https://doi.org/10.1172/jci.insight.132836.
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Research Article Immunology Inflammation

Targeting IL-17A/glucocorticoid synergy to CSF3 expression in neutrophilic airway diseases

Abstract

IL-17A plays a critical role in the pathogenesis of steroid-resistant neutrophilic airway inflammation, which is a hallmark of severe asthma and chronic obstructive pulmonary disease (COPD). Through RNA sequencing analysis of transcriptomes of human airway smooth muscle cells treated with IL-17A, dexamethasone (DEX, a synthetic glucocorticoid drug), alone or in combination, we identified a group of genes that are synergistically induced by IL-17A and DEX, including the neutrophil-promoting cytokine CSF3. In type-17 (Th17/IL-17Ahi) preclinical models of neutrophilic severe asthma (acute and chronic) and COPD, although DEX treatment was able to reduce the expression of neutrophil-mobilizing CXCL1 and CXCL2 in lung tissue, CSF3 expression was upregulated by DEX treatment. We found that DEX treatment alone failed to alleviate neutrophilic airway inflammation and pathology, and even exacerbated the disease phenotype when CSF3 was highly induced. Disruption of the IL-17A/DEX synergy by IL-17A inhibition with anti–IL-17A mAb or cyanidin-3-glucoside (C3G, a small-molecule IL-17A blocker) or depletion of CSF3 effectively rendered DEX sensitivity in type-17 preclinical models of neutrophilic airway diseases. Our study elucidates what we believe is a novel mechanism of steroid resistance in type-17 neutrophilic airway inflammation and offers an effective steroid-sparing therapeutic strategy (combined low-dose DEX and C3G) for treating neutrophilic airway diseases.

Authors

Suidong Ouyang, Caini Liu, Jianxin Xiao, Xing Chen, Andy C. Lui, Xiaoxia Li

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Figure 6

CSF3 induced by IL-17A/DEX in ASMCs is the key neutrophil survival cytokine.

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CSF3 induced by IL-17A/DEX in ASMCs is the key neutrophil survival cytok...
(A) Ten-week-old female SMA-specific (Acta2-specific) Il17rc-deficient mice (SMA-Il17rcfl/fl) and control mice (SMA-Il17rcfl/+) were subjected to the HDM-CFA type-17 acute severe asthma mode (n = 5 mice per group). Twenty-four hours after challenging, total and neutrophil counts in the BAL were quantified. Data represent mean ± SEM. Statistical analysis was performed using 2-tailed Student’s t test. (B) Representative BAL cells were prepared by cytospin and lung tissues were stained with H&E. All scale bars (red): 100 μm. (C) Lung cells were stained with anti-CD45, anti-CD11b, and anti-Ly6G antibodies, followed by TUNEL assay using biotinylated dNTP and streptavidin-FITC. The apoptotic neutrophils were gated as CD45+CD11b+Ly6G+FITC+ cells. Representative dot blots from 2 independent experiments are shown. (D) BM-derived neutrophils were cultured in the presence of the conditioned media collected from mouse ASMCs treated for 24 hours as indicated: IL-17A (100 ng/mL), DEX (1 μM), C3G (100 μM), anti-CSF3 antibody (0.5 μg/mL). Flow cytometry gating live neutrophils as annexin V negative and propidium iodide negative. (E) BM-derived neutrophils were loaded into the upper chamber in Transwells, and the conditioned media collected from mouse ASMCs treated for 24 hours as indicated were added to the bottom chamber. After 6 hours, the number of migrating neutrophils was counted. For D and E, data represent mean ± SD (n = 3 technical replicates). The above data are representative of 3 independent experiments.