Th1 cytokines tnf-α and ifn-γ promote corticosteroid resistance in developing human airway smooth muscle

Rodney D. Britt, Michael A. Thompson, Sarah Sasse, Christina M. Pabelick, Anthony N. Gerber, Y. S. Prakash

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

Corticosteroids (CSs) are commonly used to manage wheezing and asthma in pediatric populations. Although corticosteroids are effective in alleviating airway diseases, some children with more moderate-severe asthma phenotypes show CS resistance and exhibit significant airflow obstruction, persistent inflammation, and more frequent exacerbations. Previous studies have demonstrated that Th1 cytokines, such as TNF-α and IFN-γ, promote CS resistance in adult human airway smooth muscle (ASM). In the present study, using a human fetal ASM cell model, we tested the hypothesis that TNF-α and IFN-γ induces CS resistance. In contrast to TNF-α and IFN-γ alone, the combination of TNF-α and IFN-γ blunted the ability of fluticasone propionate (FP) to reduce expression of the chemokines CCL5 and CXCL10 despite expression of key anti-inflammatory glucocorticoid receptor target genes being largely unaffected by TNF-α and IFN-γ. Expression of the NF-κB subunit p65 and phosphorylation of Stat1 were elevated in cells treated with TNF-α and IFN-γ, an effect that remained in the presence of FP. siRNA knockdown studies demonstrated the effects of TNF-α and IFN-γ on increased p65 are mediated by Stat1, a transcription factor activated by IFN- γ. Expression of TNFAIP3, a negative regulator of NF-κB activity, was not altered by TNF-α and IFN-γ. However, the effects of TNF-α and IFN-γ were partially reduced by overexpression of TNFAIP3 but did not influence p65 expression. Together, these data suggest that IFN- γ augments the effects of TNF- α on chemokines by enhancing expression of key inflammatory pathways in the presence of CS. Interactions between TNF-α and IFN-γ -mediated pathways may promote inflammation in asthmatic children resistant to CSs.

Original languageEnglish (US)
Pages (from-to)L71-L81
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume316
Issue number1
DOIs
StatePublished - Jan 2019

Keywords

  • Airway
  • Asthma
  • Children
  • Cytokine
  • Steroid resistance

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology

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