Jing Jing Li1, Hock L Tay1, Steven Maltby1, Yang Xiang2, Fiona Eyers1, Luke Hatchwell3, Hong Zhou1, Hamish D Toop4, Jonathan C Morris4, Parameswaran Nair5, Joerg Mattes3, Paul S Foster6, Ming Yang7. 1. Priority Research Centre for Asthma and Respiratory Disease, School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle and Hunter Medical Research Institute, Callaghan, Australia. 2. Priority Research Centre for Asthma and Respiratory Disease, School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle and Hunter Medical Research Institute, Callaghan, Australia; Department of Physiology, Xiangya School of Medicine, Central South University, Changsha, China. 3. Priority Research Centre for Asthma and Respiratory Disease, Discipline of Paediatrics and Child Health, School of Medicine and Public Health, Faculty of Health, University of Newcastle and Hunter Medical Research Institute, Callaghan, Australia. 4. School of Chemistry, University of New South Wales, Sydney, Australia. 5. Firestone Institute for Respiratory Health, St Joseph's Healthcare & Department of Medicine, McMaster University, Hamilton, Ontario, Canada. 6. Priority Research Centre for Asthma and Respiratory Disease, School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle and Hunter Medical Research Institute, Callaghan, Australia. Electronic address: Paul.Foster@newcastle.edu.au. 7. Priority Research Centre for Asthma and Respiratory Disease, School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle and Hunter Medical Research Institute, Callaghan, Australia. Electronic address: Ming.Yang@newcastle.edu.au.
Abstract
BACKGROUND: Steroid-resistant asthma is a major clinical problem that is linked to activation of innate immune cells. Levels of IFN-γ and LPS are often increased in these patients. Cooperative signaling between IFN-γ/LPS induces macrophage-dependent steroid-resistant airway hyperresponsiveness (AHR) in mouse models. MicroRNAs (miRs) are small noncoding RNAs that regulate the function of innate immune cells by controlling mRNA stability and translation. Their role in regulating glucocorticoid responsiveness and AHR remains unexplored. OBJECTIVE: IFN-γ and LPS synergistically increase the expression of miR-9 in macrophages and lung tissue, suggesting a role in the mechanisms of steroid resistance. Here we demonstrate the role of miR-9 in IFN-γ/LPS-induced inhibition of dexamethasone (DEX) signaling in macrophages and in induction of steroid-resistant AHR. METHODS: MiRNA-9 expression was assessed by means of quantitative RT-PCR. Putative miR-9 targets were determined in silico and confirmed in luciferase reporter assays. miR-9 function was inhibited with sequence-specific antagomirs. The efficacy of DEX was assessed by quantifying glucocorticoid receptor (GR) cellular localization, protein phosphatase 2A (PP2A) activity, and AHR. RESULTS: Exposure of pulmonary macrophages to IFN-γ/LPS synergistically induced miR-9 expression; reduced levels of its target transcript, protein phosphatase 2 regulatory subunit B (B56) δ isoform; attenuated PP2A activity; and inhibited DEX-induced GR nuclear translocation. Inhibition of miR-9 increased both PP2A activity and GR nuclear translocation in macrophages and restored steroid sensitivity in multiple models of steroid-resistant AHR. Pharmacologic activation of PP2A restored DEX efficacy and inhibited AHR. MiR-9 expression was increased in sputum of patients with neutrophilic but not those with eosinophilic asthma. CONCLUSION: MiR-9 regulates GR signaling and steroid-resistant AHR. Targeting miR-9 function might be a novel approach for the treatment of steroid-resistant asthma.
BACKGROUND:Steroid-resistant asthma is a major clinical problem that is linked to activation of innate immune cells. Levels of IFN-γ and LPS are often increased in these patients. Cooperative signaling between IFN-γ/LPS induces macrophage-dependent steroid-resistant airway hyperresponsiveness (AHR) in mouse models. MicroRNAs (miRs) are small noncoding RNAs that regulate the function of innate immune cells by controlling mRNA stability and translation. Their role in regulating glucocorticoid responsiveness and AHR remains unexplored. OBJECTIVE: IFN-γ and LPS synergistically increase the expression of miR-9 in macrophages and lung tissue, suggesting a role in the mechanisms of steroid resistance. Here we demonstrate the role of miR-9 in IFN-γ/LPS-induced inhibition of dexamethasone (DEX) signaling in macrophages and in induction of steroid-resistant AHR. METHODS: MiRNA-9 expression was assessed by means of quantitative RT-PCR. Putative miR-9 targets were determined in silico and confirmed in luciferase reporter assays. miR-9 function was inhibited with sequence-specific antagomirs. The efficacy of DEX was assessed by quantifying glucocorticoid receptor (GR) cellular localization, protein phosphatase 2A (PP2A) activity, and AHR. RESULTS: Exposure of pulmonary macrophages to IFN-γ/LPS synergistically induced miR-9 expression; reduced levels of its target transcript, protein phosphatase 2 regulatory subunit B (B56) δ isoform; attenuated PP2A activity; and inhibited DEX-induced GR nuclear translocation. Inhibition of miR-9 increased both PP2A activity and GR nuclear translocation in macrophages and restored steroid sensitivity in multiple models of steroid-resistant AHR. Pharmacologic activation of PP2A restored DEX efficacy and inhibited AHR. MiR-9 expression was increased in sputum of patients with neutrophilic but not those with eosinophilic asthma. CONCLUSION: MiR-9 regulates GR signaling and steroid-resistant AHR. Targeting miR-9 function might be a novel approach for the treatment of steroid-resistant asthma.
Authors: Paul S Foster; Steven Maltby; Helene F Rosenberg; Hock L Tay; Simon P Hogan; Adam M Collison; Ming Yang; Gerard E Kaiko; Philip M Hansbro; Rakesh K Kumar; Joerg Mattes Journal: Immunol Rev Date: 2017-07 Impact factor: 12.988
Authors: L Chachi; M Abbasian; A Gavrila; A Alzahrani; O Tliba; P Bradding; A J Wardlaw; C Brightling; Y Amrani Journal: Allergy Date: 2016-09-15 Impact factor: 13.146