90 results found
Frankenberg Garcia J, Rogers A, Mak J, et al., 2022, Mitochondrial transfer regulates bioenergetics in healthy and COPD airway smooth muscle, American Journal of Respiratory Cell and Molecular Biology, Vol: 67, Pages: 471-481, ISSN: 1044-1549
Mitochondrial dysfunction has been reported in chronic obstructive pulmonary disease (COPD). Transfer of mitochondria from mesenchymal stem cells to airway smooth muscle cells (ASMCs) can attenuate oxidative stress-induced mitochondrial damage. It is not known whether mitochondrial transfer can occur between structural cells in the lungs or what role this may have in modulating bioenergetics and cellular function in healthy and COPD airways. Here, we show that ASMCs from both healthy ex-smokers and subjects with COPD can exchange mitochondria, a process that happens, at least partly, via extracellular vesicles. Exposure to cigarette smoke induces mitochondrial dysfunction and leads to an increase in the donation of mitochondria by ASMCs, suggesting that the latter may be a stress response mechanism. Healthy ex-smoker ASMCs that receive mitochondria show increases in mitochondrial biogenesis and respiration and a reduction in cell proliferation, irrespective of whether the mitochondria are transferred from healthy ex-smoker or COPD ASMCs. Our data indicate that mitochondrial transfer between structural cells is a homeostatic mechanism for the regulation of bioenergetics and cellular function within the airways and may represent an endogenous mechanism for reversing the functional consequences of mitochondrial dysfunction in diseases such as COPD.
Michaeloudes C, Abubakar-Waziri H, Lakhdar R, et al., 2022, Molecular mechanisms of oxidative stress in asthma, Molecular Aspects of Medicine, Vol: 85, ISSN: 0098-2997
The lungs are exposed to reactive oxygen species oxygen (ROS) produced as a result of inhalation of oxygen, as well as smoke and other air pollutants. Cell metabolism and the NADPH oxidases (Nox) generate low levels of intracellular ROS that act as signal transduction mediators by inducing oxidative modifications of histones, enzymes and transcription factors. Redox signalling is also regulated by localised production and sensing of ROS in mitochondria, the endoplasmic reticulum (ER) and inside the nucleus. Intracellular ROS are maintained at low levels through the action of a battery of enzymatic and non-enzymatic antioxidants. Asthma is a heterogeneous airway inflammatory disease with different immune endotypes; these include atopic or non-atopic Th2 type immune response associated with eosinophilia, or a non-Th2 response associated with neutrophilia. Airway remodelling and hyperresponsiveness accompany the inflammatory response in asthma. Over-production of ROS resulting from infiltrating immune cells, particularly eosinophils and neutrophils, and a concomitant impairment of antioxidant responses lead to development of oxidative stress in asthma. Oxidative stress is augmented in severe asthma and during exacerbations, as well as by air pollution and obesity, and causes oxidative damage of tissues promoting airway inflammation and hyperresponsiveness. Furthermore, deregulated Nox activity, mitochondrial dysfunction, ER stress and/or oxidative DNA damage, resulting from exposure to irritants, inflammatory mediators or obesity, may lead to redox-dependent changes in cell signalling. ROS play a central role in airway epithelium-mediated sensing, development of innate and adaptive immune responses, and airway remodelling and hyperresponsiveness. Nonetheless, antioxidant compounds have proven clinically ineffective as therapeutic agents for asthma, partly due to issues with stability and in vivo metabolism of these compounds. The compartmentalised nature of ROS product
Chen R, Michaeloudes C, Liang Y, et al., 2022, ORMDL3 regulates cigarette smoke-induced endoplasmic reticulum stress in airway smooth muscle cells, JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY, Vol: 149, Pages: 1445-+, ISSN: 0091-6749
Kermani N, Song W-J, Badi Y, et al., 2021, Sputum ACE2, TMPRSS2 and FURIN gene expression in severe neutrophilic asthma, Respiratory Research, Vol: 22, ISSN: 1465-9921
BackgroundPatients with severe asthma may have a greater risk of dying from COVID-19 disease. Angiotensin converting enzyme-2 (ACE2) and the enzyme proteases, transmembrane protease serine 2 (TMPRSS2) and FURIN, are needed for viral attachment and invasion into host cells.MethodsWe examined microarray mRNA expression of ACE2, TMPRSS2 and FURIN in sputum, bronchial brushing and bronchial biopsies of the European U-BIOPRED cohort. Clinical parameters and molecular phenotypes, including asthma severity, sputum inflammatory cells, lung functions, oral corticosteroid (OCS) use, and transcriptomic-associated clusters, were examined in relation to gene expression levels.ResultsACE2 levels were significantly increased in sputum of severe asthma compared to mild-moderate asthma. In multivariate analyses, sputum ACE2 levels were positively associated with OCS use and male gender. Sputum FURIN levels were significantly related to neutrophils (%) and the presence of severe asthma. In bronchial brushing samples, TMPRSS2 levels were positively associated with male gender and body mass index, whereas FURIN levels with male gender and blood neutrophils. In bronchial biopsies, TMPRSS2 levels were positively related to blood neutrophils. The neutrophilic molecular phenotype characterised by high inflammasome activation expressed significantly higher FURIN levels in sputum than the eosinophilic Type 2-high or the pauci-granulocytic oxidative phosphorylation phenotypes.ConclusionLevels of ACE2 and FURIN may differ by clinical or molecular phenotypes of asthma. Sputum FURIN expression levels were strongly associated with neutrophilic inflammation and with inflammasome activation. This might indicate the potential for a greater morbidity and mortality outcome from SARS-CoV-2 infection in neutrophilic severe asthma.
Michaeloudes C, Li X, Mak JCW, et al., 2021, Study of Mesenchymal Stem Cell-Mediated Mitochondrial Transfer in In Vitro Models of Oxidant-Mediated Airway Epithelial and Smooth Muscle Cell Injury., Methods Mol Biol, Vol: 2269, Pages: 93-105
Mesenchymal stem cells (MSCs) have emerged as an attractive candidate for cell-based therapy. In the past decade, many animal and pilot clinical studies have demonstrated that MSCs are therapeutically beneficial for the treatment of obstructive lung diseases such as asthma and chronic obstructive pulmonary disease (COPD). However, due to the scarcity of adult human MSCs, human-induced pluripotent stem cells mesenchymal stem cells (iPSCs) are now increasingly used as a source of MSCs. iPSCs are derived by reprogramming somatic cells from a wide variety of tissues such as skin biopsies and then differentiating them into iPSC-MSCs. One of the mechanisms through which MSCs exert their protective effects is mitochondrial transfer. Specifically, transfer of mitochondria from iPSC-MSCs to lung cells was shown to protect lung cells against oxidative stress-induced mitochondrial dysfunction and apoptosis and to reduce lung injury and inflammation in in vivo models of lung disease. In this chapter, we detail our methods to visualize and quantify iPSC-MSC-mediated mitochondrial transfer and to study its effects on oxidant-induced airway epithelial and smooth muscle cell models of acute airway cell injury.
Haji G, Wiegman C, Michaeloudes C, et al., 2020, Mitochondrial dysfunction in airways and quadriceps muscle of patients with Chronic Obstructive Pulmonary Disease, Respiratory Research, Vol: 21, ISSN: 1465-9921
BackgroundMitochondrial damage and dysfunction have been reported in airway and quadriceps muscle cells of patients with chronic obstructive pulmonary disease (COPD). We determined the concomitance of mitochondrial dysfunction in these cells in COPD.MethodsBronchial biopsies were obtained from never- and ex-smoker volunteers and COPD patients (GOLD Grade 2) and quadriceps muscle biopsies from the same volunteers in addition to COPD patients at GOLD Grade 3/4 for measurement of mitochondrial function.ResultsDecreased mitochondrial membrane potential (ΔΨm), increased mitochondrial reactive oxygen species (mtROS) and decreased superoxide dismutase 2 (SOD2) levels were observed in mitochondria isolated from bronchial biopsies from Grade 2 patients compared to healthy never- and ex-smokers. There was a significant correlation between ΔΨm and FEV1 (% predicted), transfer factor of the lung for carbon monoxide (TLCOC % predicted), 6-min walk test and maximum oxygen consumption. In addition, ΔΨm was also associated with decreased expression levels of electron transport chain (ETC) complex proteins I and II. In quadriceps muscle of Grade 2 COPD patients, a significant increase in total ROS and mtROS was observed without changes in ΔΨm, SOD2 or ETC complex protein expression. However, quadriceps muscle of GOLD Grade 3/4 COPD patients showed an increased mtROS and decreased SOD2 and ETC complex proteins I, II, III and V expression.ConclusionsMitochondrial dysfunction in the airways, but not in quadriceps muscle, is associated with airflow obstruction and exercise capacity in Grade 2 COPD. Oxidative stress-induced mitochondrial dysfunction in the quadriceps may result from similar disease processes occurring in the lungs.
Orton CM, Garner JL, Shah TA, et al., 2020, Metered Cryospray Modulates Bronchial Epithelial Gene Expression in Patients with Chronic Obstructive Pulmonary Disease, Publisher: EUROPEAN RESPIRATORY SOC JOURNALS LTD, ISSN: 0903-1936
Michaeloudes C, Bhavsar PK, Mumby S, et al., 2020, Role of metabolic reprogramming in pulmonary innate immunity and Its impact on lung diseases, Journal of Innate Immunity, Vol: 12, Pages: 1-16, ISSN: 1662-811X
Lung innate immunity is the first line of defence against inhaled allergens, pathogens and environmental pollutants. Cellular metabolism plays a key role in innate immunity. Catabolic pathways, including glycolysis and fatty acid oxidation (FAO), are interconnected with biosynthetic and redox pathways. Innate immune cell activation and differentiation trigger extensive metabolic changes that are required to support their function. Pro-inflammatory polarisation of macrophages and activation of dendritic cells, mast cells and neutrophils are associated with increased glycolysis and a shift towards the pentose phosphate pathway and fatty acid synthesis. These changes provide the macromolecules required for proliferation and inflammatory mediator production and reactive oxygen species for anti-microbial effects. Conversely, anti-inflammatory macrophages use primarily FAO and oxidative phosphorylation to ensure efficient energy production and redox balance required for prolonged survival. Deregulation of metabolic reprogramming in lung diseases, such as asthma and chronic obstructive pulmonary disease, may contribute to impaired innate immune cell function. Understanding how innate immune cell metabolism is altered in lung disease may lead to identification of new therapeutic targets. This is important as drugs targeting a number of metabolic pathways are already in clinical development for the treatment of other diseases such as cancer.
Garcia JF, Xu B, Hui C, et al., 2019, REGULATION OF MITOCHONDRIAL TRANSFER BETWEEN AIRWAY SMOOTH MUSCLE CELLS (ASMCS): RELEVANCE TO COPD, Winter Meeting of the British-Thoracic-Society, Publisher: BMJ PUBLISHING GROUP, Pages: A48-A49, ISSN: 0040-6376
Garcia JF, Mak J, Xu B, et al., 2019, Regulation of mitochondrial transfer between airway smooth muscle cells: relevance to COPD, International Congress of the European-Respiratory-Society (ERS), Publisher: EUROPEAN RESPIRATORY SOC JOURNALS LTD, ISSN: 0903-1936
The majority of patients with asthma are well controlled by current combination therapy consisting of ICSs and LABAs. Patients with severe asthma continue to have uncontrolled asthma symptoms despite being established on high-dose ICSs and often need additional OCS therapy. These patients are relatively insensitive to the therapeutic benefits of corticosteroids, which highlights the need for the development of new treatments to overcome corticosteroid resistance. A number of conditions have been associated with corticosteroid insensitivity in severe asthma, including obesity, cigarette smoking, vitamin D deficiency and possibly respiratory infections. Understanding the underlying mechanisms driving the relative corticosteroid insensitivity would be of benefit in order to identify the defects that lead to impaired response in asthmatic cells. Corticosteroids mediate their effects through the glucocorticoid receptor. Molecular mechanisms identified to date include: impaired nuclear translocation of glucocorticoid receptor; activation of the mitogen-activated protein kinase (MAPK) pathways, in particular p38 MAPK; activation of transcription factors by IFN-γ; or increased oxidative stress resulting in a reduction in histone deacetylase expression and activity.
Garcia JF, Michaeloudes C, Xu B, et al., 2019, Mechanisms of Mitochondrial Transfer in Health and Disease, International Conference of the American-Thoracic-Society, Publisher: AMER THORACIC SOC, ISSN: 1073-449X
Tsang J, Xu B, Xie J, et al., 2019, Effect of Corticosteroids on Metabolic Gene Expression in Airway Smooth Muscle Cells, International Conference of the American-Thoracic-Society, Publisher: AMER THORACIC SOC, ISSN: 1073-449X
Bhavsar PK, 2018, Role of humoral defense in severe asthma, American Journal of Respiratory and Critical Care Medicine, Vol: 197, Pages: 1369-1371, ISSN: 1073-449X
Dhesi SS, Chung KF, Michaeloudes C, et al., 2017, THE EFFECT OF LONG ACTING BETA-AGONISTS ON GLUCOCORTICOID RECEPTOR AND IMPORTIN-7 NUCLEAR TRANSLOCATION IN AIRWAY SMOOTH MUSCLE CELLS, Winter Meeting of the British-Thoracic-Society, Publisher: BMJ PUBLISHING GROUP, Pages: A55-A55, ISSN: 0040-6376
Mullegama R, Pavlidis S, Chung KF, et al., 2017, CLINICAL AND TRANSCRIPTOMIC PROFILES OF SEVERE ASTHMATICS WITH HIGH OR LOW EXPRESSION OF THE GLUCOCORTICOID RECEPTOR AND IMPORTIN-7, Winter Meeting of the British-Thoracic-Society, Publisher: BMJ PUBLISHING GROUP, Pages: A40-A41, ISSN: 0040-6376
Lo C-Y, Michaeloudes C, Bhavsar PK, et al., 2017, Reduced suppressive effect of beta(2)-adrenoceptor agonist on fibrocyte function in severe asthma, RESPIRATORY RESEARCH, Vol: 18, ISSN: 1465-993X
BackgroundPatients with severe asthma have increased airway remodelling and elevated numbers of circulating fibrocytes with enhanced myofibroblastic differentiation capacity, despite being treated with high doses of corticosteroids, and long acting β2-adrenergic receptor (AR) agonists (LABAs). We determined the effect of β2-AR agonists, alone or in combination with corticosteroids, on fibrocyte function.MethodsNon-adherent non-T cells from peripheral blood mononuclear cells isolated from healthy subjects and patients with non-severe or severe asthma were treated with the β2-AR agonist, salmeterol, in the presence or absence of the corticosteroid dexamethasone. The number of fibrocytes (collagen I+/CD45+ cells) and differentiating fibrocytes (α-smooth muscle actin+ cells), and the expression of CC chemokine receptor 7 and of β2-AR were determined using flow cytometry. The role of cyclic adenosine monophosphate (cAMP) was elucidated using the cAMP analogue 8-bromoadenosine 3′,5′-cyclic monophosphate (8-Br-cAMP) and the phosphodiesterase type IV (PDE4) inhibitor, rolipram.ResultsSalmeterol reduced the proliferation, myofibroblastic differentiation and CCR7 expression of fibrocytes from healthy subjects and non-severe asthma patients. Fibrocytes from severe asthma patients had a lower baseline surface β2-AR expression and were relatively insensitive to salmeterol but not to 8-Br-cAMP or rolipram. Dexamethasone increased β2-AR expression and enhanced the inhibitory effect of salmeterol on severe asthma fibrocyte differentiation.ConclusionsFibrocytes from patients with severe asthma are relatively insensitive to the inhibitory effects of salmeterol, an effect which is reversed by combination with corticosteroids.
Michaeloudes C, Bhavsar PK, Mumby S, et al., 2017, Dealing with Stress: Defective Metabolic Adaptation in Chronic Obstructive Pulmonary Disease Pathogenesis, Annals of the American Thoracic Society, Vol: 14, Pages: S374-S382, ISSN: 2329-6933
The mitochondrion is the main site of energy production and ahub of key signaling pathways. It is also central in stress-adaptiveresponse due to its dynamic morphology and ability to interactwith other organelles. In response to stress, mitochondria fuseinto networks to increase bioenergetic efficiency and protectagainst oxidative damage. Mitochondrial damage triggerssegregation of damaged mitochondria from the mitochondrialnetwork through fission and their proteolytic degradation bymitophagy. Post-translational modifications of themitochondrial proteome and nuclear cross-talk lead toreprogramming of metabolic gene expression to maintain energyproduction and redox balance. Chronic obstructive pulmonarydisease (COPD) is caused by chronic exposure to oxidativestress arising from inhaled irritants, such as cigarette smoke.Impaired mitochondrial structure and function, due tooxidative stress–induced damage, may play a key role incausing COPD. Deregulated metabolic adaptation maycontribute to the development and persistence of mitochondrialdysfunction in COPD. We discuss the evidence for deregulatedmetabolic adaptation and highlight important areas forinvestigation that will allow the identification of moleculartargets for protecting the COPD lung from the effects ofdysfunctional mitochondria.
Li X, Michaeloudes C, Zhang Y, et al., 2017, Mesenchymal stem cells alleviate oxidative stress-induced mitochondrial dysfunction in the airways., Journal of Allergy and Clinical Immunology, Vol: 141, Pages: 1634-1645.e5, ISSN: 0091-6749
BACKGROUND: Oxidative stress-induced mitochondrial dysfunction may contribute to inflammation and remodeling in chronic obstructive pulmonary disease (COPD). Mesenchymal stem cells (MSCs) protect against lung damage in animal models of COPD. It is unknown whether these effects occur through attenuating mitochondrial dysfunction in airway cells. OBJECTIVE: To examine the effect of induced-pluripotent stem cell-derived MSCs (iPSC-MSCs) on oxidative stress-induce mitochondrial dysfunction in human airway smooth muscle cells (ASMCs) in vitro and in mouse lungs in vivo. METHODS: ASMCs were co-cultured with iPSC-MSCs in the presence of cigarette smoke medium (CSM), and mitochondrial reactive oxygen species (ROS), mitochondrial membrane potential (ΔΨm) and apoptosis were measured. Conditioned media from iPSC-MSCs and trans-well co-cultures were used to detect any paracrine effects. The effect of systemic injection of iPSC-MSCs on airway inflammation and hyper-responsiveness in ozone-exposed mice was also investigated. RESULTS: Co-culture of iPSC-MSCs with ASMCs attenuated CSM-induced mitochondrial ROS, apoptosis and ΔΨm loss in ASMCs. iPSC-MSC-conditioned media or trans-well co-cultures with iPSC-MSCs reduced CSM-induced mitochondrial ROS but not ΔΨm or apoptosis in ASMCs. Mitochondrial transfer from iPSC-MSCs to ASMCs was observed after direct co-culture and was enhanced by CSM. iPSC-MSCs attenuated ozone-induced mitochondrial dysfunction, airway hyper-responsiveness and inflammation in mouse lungs. CONCLUSION: iPSC-MSCs offered protection against oxidative stress-induced mitochondrial dysfunction in human ASMCs and in mouse lungs, whilst reducing airway inflammation and hyper-responsiveness. These effects are, at least partly, dependent on cell-cell contact that allows for mitochondrial transfer, and paracrine regulation. Therefore, iPSC-MSCs show promise as a therapy for oxidative stress-dependent lung diseases such as COPD.
Shaikh N, Johnson M, Hall D, et al., 2017, Intracellular interactions of umeclidinium and vilanterol in human airway smooth muscle, International Journal of Chronic Obstructive Pulmonary Disease, Vol: 12, Pages: 1903-1913, ISSN: 1176-9106
Background: Intracellular mechanisms of action of umeclidinium (UMEC), a long-acting muscarinic receptor antagonist, and vilanterol (VI), a long-acting β2-adrenoceptor (β2R) agonist, were investigated in target cells: human airway smooth-muscle cells (ASMCs).Materials and methods: ASMCs from tracheas of healthy lung-transplant donors were treated with VI, UMEC, UMEC and VI combined, or control compounds (salmeterol, propranolol, ICI 118.551, or methacholine [MCh]). Cyclic adenosine monophosphate (cAMP) was measured using an enzyme-linked immunosorbent assay, intracellular free calcium ([Ca2+]i) using a fluorescence assay, and regulator of G-protein signaling 2 (RGS2) messenger RNA using real-time quantitative polymerase chain reaction.Results: VI and salmeterol (10–12–10–6 M) induced cAMP production from ASMCs in a concentration-dependent manner, which was greater for VI at all concentrations. β2R antagonism by propranolol or ICI 118.551 (10–12–10–4 M) resulted in concentration-dependent inhibition of VI-induced cAMP production, and ICI 118.551 was more potent. MCh (5×10–6 M, 30 minutes) attenuated VI-induced cAMP production (P<0.05), whereas pretreatment with UMEC (10–8 M, 1 hour) restored the magnitude of VI-induced cAMP production. ASMC stimulation with MCh (10–11–5×10–6 M) resulted in a concentration-dependent increase in [Ca2+]i, which was attenuated with UMEC pretreatment. Reduction of MCh-induced [Ca2+]i release was greater with UMEC + VI versus UMEC. UMEC enhanced VI-induced RGS2 messenger RNA expression.Conclusion: These data indicate that UMEC reverses cholinergic inhibition of VI-induced cAMP production, and is a more potent muscarinic receptor antagonist when in combination with VI versus either alone.
Bhavsar PK, Sehra G, Johnson M, et al., 2017, Pharmacological characterization Of Maba, Gsk961081 on human airway smooth muscle cells, International Conference of the American-Thoracic-Society (ATS), Publisher: American Thoracic Society, ISSN: 1073-449X
Rasiah MG, Michaeloudes C, Svermova T, et al., 2016, PLASMA SYNDECAN-1 LEVEL AS A PREDICTIVE MARKER OF VASOPLEGIA ASSOCIATED WITH SURGERY REQUIRING CARDIOPULMONARY BYPASS AND POSSIBLE INVOLVEMENT OF OXIDATIVE STRESS, British Thoracic Society Winter Meeting 2016, Publisher: BMJ PUBLISHING GROUP, Pages: A9-A9, ISSN: 0040-6376
Shaikh N, Johnson M, Riley J, et al., 2016, Effects Of Vilanterol And Umeclidinium Alone And In Combination In Human Airway Smooth Muscle Cells, International Conference of the American-Thoracic-Society (ATS), Publisher: American Thoracic Society, ISSN: 1073-449X
Zhang Q, Cox M, Liang Z, et al., 2016, Airway microbiota in severe asthma and relationship to asthma severity and phenotypes, PLOS One, Vol: 11, ISSN: 1932-6203
Background: The lower airways harbor a community of bacterial species which is altered in asthma. Objectives: We examined whether the lower airway microbiota were related to measures of asthma severityMethods: We prospectively recruited 26 severe asthma, 18 non-severe asthma and 12 healthy subjects. DNA was extracted from induced sputum and PCR amplification of the V3-V5 region of bacterial 16S rRNA gene was performed. Results: We obtained 138,218 high quality sequences which were rarefied at 133 sequences/sample. Twenty OTUs had sequences ≥1% of total. There were marked differences in the distribution of Phyla between groups (P=2.8x10-118). Bacteroidetes and Fusobacteria were reduced in non-severe and severe asthmatic groups. Proteobacteria were more common in non-severe asthmatics compared to controls (OR=2.26; 95% CI=1.94-2.64) and Firmicutes were increased in severe asthmatics compared to controls (OR=2.15; 95%CI=1.89-2.45). Streptococcal OTUs amongst the Firmicutes were associated with recent onset asthma, rhinosinusitis and sputum eosinophilia.Conclusions: Sputum microbiota in severe asthma differs from healthy controls and non-severe asthmatics, and is characterized by the presence of Streptococcus spp with eosinophilia. Whether these organisms are causative for the pathophysiology of asthma remains to be determined.
Li X, Michaeloudes C, Zhang Y, et al., 2016, Induced-Pluripotent Stem Cell-Derived Mesenchymal Stem Cells Attenuate Cigarette Smoke-Induced Mitochondrial Dysfunction And Apoptosis In Airway Smooth Muscle Cells, International Conference of the American-Thoracic-Society (ATS), Publisher: AMER THORACIC SOC, ISSN: 1073-449X
Colley T, Mercado N, Kunori Y, et al., 2015, Defective sirtuin-1 increases IL-4 expression through acetylation of GATA-3 in patients with severe asthma., Journal of Allergy and Clinical Immunology, Vol: 137, Pages: 1595-1597.e7, ISSN: 1097-6825
Marwick JA, Tudor C, Khorasani N, et al., 2015, Oxidants Induce a Corticosteroid-Insensitive Phosphorylation of Histone 3 at Serine 10 in Monocytes, PLOS One, Vol: 10, ISSN: 1932-6203
Khorasani N, Baker J, Johnson M, et al., 2015, Reversal of corticosteroid insensitivity by p38 MAPK inhibition in peripheral blood mononuclear cells from COPD, International Journal of Chronic Obstructive Pulmonary Disease, Vol: 10, Pages: 283-291, ISSN: 1176-9106
Background: Corticosteroids (CS) have limited efficacy in the treatment of chronic obstructivepulmonary disease (COPD). p38 mitogen-activated protein kinase (MAPK) activation isincreased in lung macrophages of COPD. We investigated whether p38 MAPK inhibitioncan modulate CS insensitivity of peripheral blood mononuclear cells (PBMCs) from patientswith COPD.Methods: PBMCs from patients with COPD (n=8) or healthy smokers (n=8) were exposed tolipopolysaccharide (LPS) with a selective p38 MAPK inhibitor (GW856553; 10-10–10-6 M),with dexamethasone (10-10–10-6 M), or with both. Phosphorylated glucocorticoid receptor (GR)was measured by Western blot.Results: Baseline (P,0.01) and LPS-induced (P,0.05) CXCL8 release was greater in PBMCsfrom COPD compared to healthy smokers. Inhibition of LPS-induced CXCL8 release by dexamethasone(10-6 M) was reduced, and baseline and LPS-induced p38 MAPK activation increasedin PBMCs of COPD. GW856553 (10-9 and 10-10 M) synergistically increased the inhibitoryeffect of dexamethasone (10-8 and 10-6 M) on LPS-induced CXCL8 release in COPD. Similarresults were obtained for IL-6 release. GW856553 inhibited dexamethasone- and LPS-activatedphosphorylation of serine 211 on GR. CS insensitivity in COPD PBMCs is reversed by inhibitionof p38 MAPK activity, partly by preventing phosphorylation of GR at serine 211.Conclusion: p38 MAPK inhibition may be beneficial in COPD by restoring CS sensitivity.
Lo C-Y, Bhavsar PK, Michaeloudes C, et al., 2015, Long-Acting Beta2 Adrenoceptor Agonist Suppresses Fibrocytes In Non- Severe Asthma But Not In Severe Asthma, International Conference of the American-Thoracic-Society (ATS), Publisher: AMER THORACIC SOC, ISSN: 1073-449X
Chang P-J, Michaeloudes C, Zhu J, et al., 2015, Impaired nuclear translocation of the glucocorticoid receptor in corticosteroid-insensitive airway smooth muscle in severe asthma, American Journal of Respiratory and Critical Care Medicine, Vol: 191, Pages: 54-62, ISSN: 1073-449X
Rationale: Patients with severe asthma (SA) are less responsive to the beneficial effects of corticosteroid (CS) therapy, and relative CS insensitivity has been shown in airway smooth muscle cells (ASMC) from patients with SA.Objectives: We investigated whether there was a defect in the actions of the glucocorticoid receptor (GR) underlying the ability of CS to suppress the inflammatory response in ASMC of patients with SA. ASMC from healthy subjects (n = 10) and subjects with severe (n = 8) and nonsevere asthma (N-SA; n = 8) were cultured from endobronchial biopsies.Measurements and Main Results: GR expression in ASMC from SA and N-SA was reduced compared with that from healthy subjects by 49% (P < 0.01). Although baseline levels of nuclear GR were similar, GR nuclear translocation induced by dexamethasone (10−7 M) in SA was 60% of that measured in either healthy subjects or subjects with N-SA. Tumor necrosis factor (TNF)-α induced greater nuclear factor (NF)-κB (p65) mRNA expression in ASMC from subjects with SA (5.6- vs. 2.0-fold; P < 0.01), whereas baseline and TNF-α–induced nuclear translocation and dexamethasone-mediated suppression of p65 expression were similar between groups. Dexamethasone, although not modulating TNF-α–induced p65 nuclear translocation, attenuated p65 recruitment to the CCL11 promoter in the healthy and N-SA groups, but this suppressive effect was impaired in subjects with SA.Conclusions: Decreased GR expression with impaired nuclear translocation in ASMC, associated with reduced dexamethasone-mediated attenuation of p65 recruitment to NF-κB–dependent gene promoters, may underlie CS insensitivity of severe asthma.
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