When is the best time and grade to start ruxolitinib in corticosteroid-refractory acute graft-versus-host-disease: A multi-center research

OBJECTIVE

Ruxolitinib was recently approved to treat corticosteroid-resistant acute graft-versus-host disease (GvHD). However, it is unknown as to whether starting ruxolitinib at a lower versus higher acute GvHD grade or earlier versus later affected outcomes. This study identified the impact of starting acute GvHD grade and start time after declaring corticosteroid resistance and the effect on complete and overall response rates to ruxolitinib therapy.

METHODS

Retrospective, observational multi-center study. We divided cohorts into starting ruxolitinib ≤ 7 days (N = 45) versus at > 7 days after declaring corticosteroid resistance (N = 24).

RESULTS

In ≤ 7 days cohort complete response (CR) rates at day 28 were 69% (54, 81%) versus 25% (11, 47%; p = .001) in > 7 days cohort, and overall response (OR) rates were 91% (78, 96%) versus 80% (48, 92%; p = .25).

CONCLUSIONS

Our data suggest that starting ruxolitinib in ≤ 7 days of declaring corticosteroid failure regardless of G vHD grade improves complete response rate but not OR rates. Starting ruxolitinib at grade I and within 7 days may get a more significant response.

Clinical Care Team's Guide for Awareness on Risk Assessment of Eltrombopag Complicating Acute Kidney Injury in Relapsed Immune Thrombocytopenic Patients: A Case Report

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder caused by antigen-specific T cells and antiplatelet autoantibodies that inhibit platelet production in the bone marrow or destroy platelets in the spleen. ITP is a form of autoimmunity and is closely associated with inflammation. Corticosteroids are the first-line therapy for ITP, with a total response rate of 53-80%. However, corticosteroid therapy is associated with significant side effects and is often ineffective in patients with corticosteroid-resistant or -intolerant disease. Eltrombopag has been validated as a second-line option in ITP therapy. Despite several studies demonstrating the efficacy and safety of Eltrombopag in immune thrombocytopenia patients, the prevalence of Eltrombopag-induced acute kidney injury has been observed. This case report describes a patient who experienced acute kidney injury during Eltrombopag therapy. A sudden increase in serum creatinine to 6.7 mg/dL and metabolic acidosis occurred after eight weeks of Eltrombopag. The patient's renal failure had worsened, proteinuria was detected, and emergency hemodialysis was initiated. With vigilant kidney function screening and prompt treatment, the patient's renal function improved remarkably following cessation of Eltrombopag and initiation of hemodialysis. This case highlights the importance of comprehensive medication history-taking and vigilant kidney function screening in patients receiving Eltrombopag.

Mechanisms underlying corticosteroid resistance in patients with asthma: a review of current knowledge

INTRODUCTION

Corticosteroids are the most cost-effective anti-inflammatory drugs available for the treatment of asthma. Despite their effectiveness, several asthmatic patients have corticosteroid resistance or insensitivity and exhibit a poor response. Corticosteroid insensitivity implies a poor prognosis due to challenges in finding alternative therapeutic options for asthma.

AREAS COVERED

In this review, we describe asthma phenotypes and endotypes, as well as their differential responsiveness to corticosteroids. In addition, we describe the mechanism of action of corticosteroids underlying their regulation of the expression of glucocorticoid receptors (GRs) and their anti-inflammatory effects. Furthermore, we summarize the mechanistic evidence underlying corticosteroid-insensitive asthma, which is mainly related to changes in GR gene expression, structure, and post-transcriptional modifications. Finally, various pharmacological strategies designed to reverse corticosteroid insensitivity are discussed.

EXPERT OPINION

Corticosteroid insensitivity is influenced by the asthma phenotype, endotype, and severity, and serves as an indication for biological therapy. The molecular mechanisms underlying corticosteroid-insensitive asthma have been used to develop targeted therapeutic strategies. However, the lack of clinical trials prevents the clinical application of these treatments.

[Anti-inflammatory Effects of a Src Inhibitor on the Murine Model of Asthma Exacerbation Induced by Ovalbumin and Lipopolysaccharide]

Asthma is often exacerbated by airway infection, and some patients with severe asthma may be unresponsive to conventional corticosteroid treatment. Src family kinases (SFKs) were recently implicated in the inflammatory responses of mice induced by allergen and bacterial toxin lipopolysaccharide (LPS). Therefore, we examined the effects of dasatinib (DAS), a Src inhibitor, on airway inflammation in mice induced by ovalbumin (OVA) and LPS. Male A/J mice were sensitized to OVA Day -14 and -7, challenged with intranasal OVA on Day 0, 2, 4, 6 and 8, and on Day 10, mice were also challenged with OVA via inhalation. Mice were treated intranasally with DAS or fluticasone propionate (FP), a glucocorticoid, twice daily for 3 d starting 1 d after OVA inhalation. Moreover, some mice were also administrated LPS 2 h after DAS or FP treatment to model of asthma exacerbation. One day after the last intervention, lung tissue and bronchoalveolar lavage fluid (BALF) were collected. DAS attenuated the accumulation of inflammatory cells and cytokines/chemokines in BALF induced by both OVA and OVA+LPS, while FP did not reduce accumulations induced by OVA+LPS. Therefore, targeting SFKs may be a superior therapeutic approach for asthma exacerbation by infection.

Effectiveness of Benralizumab in OCS-Dependent Severe Asthma: The Impact of 2 Years of Therapy in a Real-Life Setting

Patients with severe OCS-dependent asthma can be considered a subgroup of asthma patients with severe disease and great risk of complications, related to chronic OCS use. The introduction of biological drugs has represented a turning point in the therapeutic strategy for severe asthma, offering a valid alternative to OCS. Benralizumab, like other anti-IL-5 agents, has been shown to reduce exacerbations and OCS intake/dosage and improve symptom control and lung function. While these findings have also been confirmed in real-life studies, data on long-term efficacy are still limited.

METHODS

In this retrospective study, we evaluated the effects of 2 years of treatment with benralizumab on 44 patients with OCS-dependent severe asthma by analyzing clinical, biological and functional data.

RESULTS

After 2 years of benralizumab, 59.4% discontinued OCS and patients who continued to use OCS had their mean dose reduced by approximately 85% from baseline. Meanwhile, 85% of patients had their asthma well-controlled (ACT score > 20) and had no exacerbations, and 41.6% had normal lung function.

CONCLUSIONS

Our findings support the long-term effectiveness of benralizumab in severe OCS-dependent asthma in a real-life setting, suggesting potential reductive effects on costs and complications such as adverse pharmacological events.

Involvement of autophagy in exacerbation of eosinophilic airway inflammation in a murine model of obese asthma

Obesity is a common comorbidity in patients with asthma, and obese asthma patients present the most refractory phenotype among patients with severe asthma. Similar to the observations in non-obese asthma patients, clinical studies have revealed heterogeneity in obese asthma patients, including the occurrences of T helper (Th)2-high and Th2-low phenotypes. However, the mechanisms underlying obesity-related asthma are not completely understood. Though macroautophagy/autophagy is involved in asthma and obesity, its role in obesity-associated asthma is unknown. We hypothesized that autophagy is involved in the pathogenesis of obese asthma. For our investigations, we used high-fat diet-induced Atg5 (autophagy related 5)-deficient mice and epithelial cell-specific atg5^−/− (Scgb1a1/CCSP-atg5^−/−) obesity-induced mice. House dust mite (HDM)-sensitized atg5^−/− obese mice exhibited marked eosinophilic inflammation and airway hyper-reactivity (AHR), compared to wild-type (WT) obese mice. Analyses of atg5^−/− obese mice showed increased levels of Th2 cells but not ILC2s together with elevated expression of Th2 cytokines in the lung. In response to the HDM challenge, activated epithelial autophagy was observed in lean but not obese WT mice. Epithelium-specific deletion of Atg5 induced eosinophilic inflammation in Scgb1a1/CCSP-atg5^−/− obese mice, and genetic analyses of epithelial cells from HDM-immunized atg5^−/− obesity-induced mice showed an elevated expression of thymic stromal lymphopoietin (TSLP) and IL33. Notably, HDM-sensitized atg5^−/− mice developed TSLP- and IL33-dependent eosinophilic inflammation and AHR. Our results suggest that autophagy contributes to the exacerbation of eosinophilic inflammation in obese asthma. Modulations of autophagy may be a therapeutic target in obesity-associated asthma.

Abbreviations: AHR: airway hyper-reactivity; BAL: bronchoalveolar lavage; C_dyn: dynamic compliance; BM: bone marrow; HDM: house dust mite; HFD: high-fat diet; ILC2s: type 2 innate lymphocyte cells; ROS: reactive oxygen species; R_L: lung resistance; TSLP: thymic stromal lymphopoietin; TCC: total cell count; WT: wild type.

Azithromycin modulates release of steroid-insensitive cytokines from peripheral blood mononuclear cells of patients with chronic obstructive pulmonary disease

INTRODUCTION

Oxidative stress reduces responsiveness of peripheral blood mononuclear cells (PBMCs) from patients with chronic obstructive pulmonary disease (COPD) to the anti-inflammatory effects of glucocorticoids (GCs). Azithromycin was shown to modulate corticosteroid resistance mechanisms in COPD patients. However, its ability to enhance anti-inflammatory properties of GCs on the production of cytokines by PBMCs has not well been elucidated.

MATERIAL AND METHODS

Heparinised blood was collected from 27 patients with COPD. Phytohaemagglutinin-induced release of pro-inflammatory mediators from PBMCs and production of intracellular cytokines by CD4+ and CD8+ T cells stimulated with phorbol 12-myristate 13-acetate and ionomycin in the presence or absence of 10 μg/mL azithromycin and 10 nM budesonide were determined using enzyme linked immunosorbent assay and flow cytometry.

RESULTS

Azithromycin decreased the secretion of interleukin (IL) 4, IL-5, IL-13, and IL-17A from PBMCs, as well as the production of IL-4 and IL-8 by CD4+ and CD8+ T cells. The combination of azithromycin and budesonide suppressed inflammatory response by inhibition of IL-4, IL-5, IL-8, IL-13, IL-17A, IL-33, thymic stromal lymphopoietin (TSLP), macrophage migration inhibitory factor (MIF) release from PBMCs and by reduction of the percentage of IL-4-, IL-8-, interferon γ- and tumor necrosis factor a-expressing CD4+ and CD8+ T cells. The inhibitory effect of azithromycin combined with budesonide on IL-4, IL-5, IL-8, IL-17A, TSLP production by PBMCs, as well as IL-4 and IL-8 production by T helper cells and cytotoxic T lymphocytes was significantly greater than the effect of budesonide alone.

CONCLUSIONS

Azithromycin in combination with budesonide enhances GC properties by inhibiting synthesis of pro-inflammatory cytokines in blood cells of COPD patients.

Ruxolitinib Ameliorates Airway Hyperresponsiveness and Lung Inflammation in a Corticosteroid-Resistant Murine Model of Severe Asthma

Asthma prevalence has increased considerably over the decades and it is now considered as one of the most common chronic disorders in the world. While the current anti-asthmatic therapies are effective for most asthma patients, there are 5-10% subjects whose disease is not controlled by such agents and they account for about 50% of the asthma-associated healthcare costs. Such patients develop severe asthma (SA), a condition characterized by a dominant Th1/Th17 cytokine response that is accompanied by Type 2 (T2)-low endotype. As JAK (Janus Kinase) signaling is very important for the activation of several cytokine pathways, we examined whether inhibition of JAKs might lessen the clinical and laboratory manifestations of SA. To that end, we employed a recently described murine model that recapitulates the complex immune response identified in the airways of human SA patients. To induce SA, mice were sensitized with house dust mite extract (HDME) and cyclic (c)-di-GMP and then subsequently challenged with HDME and a lower dose of c-di-GMP. In this model, treatment with the JAK inhibitor, Ruxolitinib, significantly ameliorated all the features of SA, including airway hyperresponsiveness and lung inflammation as well as total IgE antibody titers. Thus, these studies highlight JAKs as critical targets for mitigating the hyper-inflammation that occurs in SA and provide the framework for their incorporation into future clinical trials for patients that have severe or difficult-to manage asthma.

Screening and Identification of Hub Genes in the Corticosteroid Resistance Network in Human Airway Epithelial Cells via Microarray Analysis

Background and Objective: Corticosteroid resistance is a major barrier to chronic obstructive pulmonary disease (COPD), but the exact mechanism of corticosteroid resistance in COPD has been less well studied. Methods: The microarray dataset GSE11906, which includes genomic and clinical data on COPD, was downloaded from the Gene Expression Omnibus (GEO) database, and the differentially expressed genes (DEGs) were identified using R software. Gene set enrichment analysis (GSEA) and Kyoto Encyclopedia of Genes (KEGG) were utilized to enrich and analyze the gene cohort related to the response to steroid hormones, respectively. The Connectivity Map (CMap) database was used to screen corticosteroid resistance-related drugs that might exert a potential therapeutic effect. STRING was used to construct a protein-protein interaction (PPI) network of the gene cohort, and the CytoHubba plug-in of Cytoscape was used to screen the hub genes in the PPI network. The expression levels of hub genes in cigarette smoke extract (CSE)-stimulated bronchial epithelial cells were assayed by quantitative real-time PCR and western blotting. Results: Twenty-one genes were found to be correlated with the response to steroid hormones. In the CMap database, 32 small-molecule compounds that might exert a therapeutic effect on corticosteroid resistance in COPD were identified. Nine hub genes were extracted from the PPI network. The expression levels of the BMP4, FOS, FN1, EGFR, and SPP1 proteins were consistent with the microarray data obtained from molecular biology experiments. Scopoletin significantly restrained the increases in the levels of AKR1C3, ALDH3A1, FN1 and reversed the decreases of phosphorylated GR and HDAC2 caused by CSE exposure. Conclusion: The BMP4, FOS, FN1, EGFR, and SPP1 genes are closely correlated with CSE-induced glucocorticoid resistance in airway epithelial cells. Scopoletin may be a potential drug for the treatment of glucocorticoid resistance caused by CSE.

The association of FKBP5 polymorphism with asthma susceptibility in asthmatic patients

OBJECTIVES

Inhaled corticosteroids are the most effective controllers of asthma, although asthmatics vary in their response. FKBP51 is a major component of the glucocorticoid receptor which regulates its responses to corticosteroids. Therefore, the present study aims to identify the role of FKBP5 gene polymorphism in asthma susceptibility and corticosteroid resistance.

METHODS

DNA was extracted from the blood of 68 asthmatic and 40 control subjects. FKBP5 gene fragments were amplified by PCR and sequenced by the Sanger method. The sequencing results were aligned by mapping on the reference sequences of National center of Biotechnology Information (NCBI) and single nucleotide polymorphisms (SNPs) which were checked. Finally, the genotype, allele frequency and odds ratio (OR) were calculated.

RESULTS

The FKBP5 fragment sequencing revealed the presence of rs1360780 and one novel SNP found in 17 samples taken from asthmatic patients as compared to db SNP data in the NCBI database. The FKBP5 variant (rs1360780) indicated that the allele frequency of risk allele T was 41.18% in patients and 20% in control group members p<0.001 and OR=2.8 when compared to a wild C allele frequency of 58.82% in patients and 64% in the control group members. The novel SNP FKBP5 was compared to the SNP database in the NCBI database in which wild T allele was substituted with G. The novel SNP was submitted to the ClinVar Submission Portal at NCBI with accession number: rs1581842283 and confirmed an asthma susceptibility risk factor with allele G frequency of 11.76% in asthmatics and 2.5% in the control group members (OR=5.2, p<0.05), as compared to a wild T allele frequency of 88.24% in asthmatics and 97.5% in the control group members.

CONCLUSIONS

The risk allele T of rs1360780 and the novel SNP rs1581842283 risk allele G predict asthma susceptibility but show no association with corticosteroid resistant.

Corticosteroid Resistance in Smokers-A Substudy Analysis of the CORTICO-COP Randomised Controlled Trial

The CORTICO-COP trial showed that eosinophil-guided corticosteroid-sparing treatment for acute exacerbation of chronic obstructive pulmonary disease was non-inferior to standard of care and decreased the accumulated dose of systemic corticosteroids that patients were exposed to by approximately 60%. Smoking status has been shown to affect corticosteroid responsiveness. This post hoc analysis investigated whether eosinophil-guided treatment is non-inferior to conventional treatment in current smokers. The main analysis of current smokers showed no significant difference in the primary endpoint, days alive, and out of hospital within 14 days between the control group (mean, 9.8 days; 95% confidence interval (CI), 8.7-10.8) and the eosinophil-guided group (mean, 8.7 days; 95% CI, 7.5-9.9; p = 0.34). Secondary analyses of the number of exacerbations or deaths, the number of intensive care unit admissions or deaths, lung function improvement, and change in health-related quality of life also showed no significant differences between the two groups. The results of a sensitivity analysis of ex-smokers are consistent with the main analysis. Our results suggest that eosinophil-guided treatment is non-inferior to standard of care in current smokers and ex-smokers. Because data on the impact of smoking status on eosinophil-guided treatments are sparse, more randomised trials are needed to confirm our results.

Livin in synergy with Ras induces and sustains corticosteroid resistance in the airway mucosa

Rationale: Corticosteroid resistance (CR) seriously affects the therapeutic effects of steroids on many chronic inflammatory disorders, including airway allergy. The mechanism of CR development is unclear. Recent research indicates that livin, an apoptosis inhibitor, is associated with the regulation in cell activities. This study investigates the role of livin in the inducing and sustaining CR in the airway mucosa.

Methods: Nasal epithelial cells (NECs) were isolated from surgically removed nasal mucosal tissues of patients with allergic rhinitis (AR) and nasal polyps with or without CR. Differentially expressed genes in NECs were analyzed by the RNA sequencing. A CR mouse model was developed to test the role of livin in CR development.

Results: The results showed that NECs of AR patients with CR expressed high levels of livin, that was positively correlated with the thymic stromal lymphopoietin (TSLP) expression and the high Ras activation status in NECs. Livin and Ras activation mutually potentiating each other in the inducing and sustaining the TSLP expression in NECs. TSLP induced eosinophils and neutrophils to express glucocorticoid receptor-β (GRβ). Eosinophils and neutrophils with high CRβ expression were resistant to corticosteroids. Depletion of livin or inhibition of TSLP markedly attenuated CR and airway allergy.

Conclusions: Livin facilitates CR development in the airways by promoting TSLP expression in epithelial cells and the GRβ expression in eosinophils and neutrophils. Depletion of livin or inhibiting TSLP attenuates CR development and inhibits airway allergy, this has the translational potential to be used in the treatment of airway allergy.

Gut microbiome alterations and its link to corticosteroid resistance in immune thrombocytopenia

Quantitative metagenomic studies have linked the gut microbiota to autoimmune disorders. Here, we performed deep shotgun metagenomic sequencing of fecal samples from 99 immune thrombocytopenia (ITP) patients and 52 healthy controls. Dysbiosis in the gut microbiome of ITP was detected phylogenetically and functionally, and classifier based on species markers distinguished individuals with ITP from healthy controls. In particular, the abundance of Ruminococcus gnavus, Bifidobacterium longum and Akkermansia muciniphila was markedly increased in treatment-naïve ITP patients, and the alterations of microbial species were correlated with clinical indices. Functionally, the secondary bile acid biosynthesis and flagellar assembly were depleted in the gut microbiota of ITP, which may contribute to the onset of ITP by affecting the immune system. Furthermore, we found that corticosteroid treatment affected the gut microbiome of ITP. Compared with corticosteroid-sensitive ITP patients, we identified that the corticosteroid-resistant ITP patients displayed a distinct gut microbiome, which was different from that of the treatment-naïve ITP patients. Together, we provided support for the critical role of gut microbiota in the development of ITP and established a foundation for further research characterizing gut microbiota in relation to corticosteroid resistance of ITP.

[The Involvement of Src in Airway Inflammation Induced by Repeated Exposure to Lipopolysaccharide in Mice]

Corticosteroid insensitive airway inflammation is one of major barrier to effective managements of chronic airway diseases, such as chronic obstructive pulmonary disease (COPD) and severe asthma. The role of nonreceptor tyrosine kinase Src is important in airway inflammation in mice models of atopic asthma and COPD. Thus, in this study, we determined the effects of Src inhibitor, dasatinib, on airway inflammation induced by repeated intranasal exposure to lipopolysaccharide (LPS). Male mice (A/J strain, 5 weeks old) were intranasally exposed to LPS twice daily for 3 d, and dasatinib was intranasally treated 2 h prior to each LPS exposure. A day after the last stimulation, lungs and bronchoalveolar lavage fluid (BALF) were collected. Dasatinib attenuated the accumulation of inflammatory cells in lungs, and the increase in the numbers of inflammatory cells and the accumulation of cytokines/chemokines in BALF in a dose dependent manner. Therefore, this study suggested that targeting the Src can provide a new therapeutic approach for corticosteroid insensitive pulmonary diseases.

[TNF-α Decreased Corticosteroid Responsiveness in Mice Models of Airway Inflammation Induced by Double Strand RNA and/or Tobacco Smoke Exposure]

Reduction of corticosteroid responsiveness is one of the important clinical problems in chronic obstructive pulmonary disease (COPD). In this study, we determined the effects of neutralization of tumor necrosis factor-α (TNF-α) on corticosteroid insensitivity in mice models of airway inflammation induced by poly(I:C) and tobacco smoke (TS) exposure. Mice (male A/J strain, 5 weeks old) were exposed to TS for 10 d, or TS for 11 d and poly(I:C) for 3 d. Anti-TNF-α antibody was intranasally treated once every other day 2 h before the TS exposure, and dexamethasone 21-phosphate (DEX) was treated 30 min before the TS or poly(I:C) exposure. On the next day of the last stimulation, mice were sacrificed. The combination treatment of DEX and TNF-α neutralization was significantly attenuated the increase of the numbers of inflammatory cells in BALF and the TNF-α mRNA expression levels induced by TS and poly(I:C) exposure, even though TNF-α neutralization alone had little effect. These data indicated that neutralization of TNF-α restores corticosteroid responsiveness. Therefore, our study suggests that targeting TNF-α signaling pathway provides a new therapeutic approach to corticosteroid refractory airway diseases.

Jinwei Tang modulates HDAC2 expression in a rat model of COPD

The aim of the present study was to investigate the effect of a Traditional Chinese Herbal Medicine (TCHM), named Jinwei Tang on histone deacetylase 2 (HDAC2) and its role in the regulation of corticosteroid resistance in a rat model of chronic obstructive pulmonary disease (COPD). Male Wistar rats were divided into five groups (each n=10): COPD group, established by the intratracheal instillation of lipopolysaccharide and passive smoke exposure, and control, budesonide, theophylline + budesonide and Jinwei Tang + budesonide groups. Lung function was measured, lung tissue histopathology was examined and HDAC2 expression in the lung was assessed by immunohistochemistry. In addition, protein levels of interleukin-8 (IL-8), tumor necrosis factor (TNF)-α and HDAC2 in lung homogenate were quantified by ELISA. The rat COPD model exhibited alterations of the ratio of forced expiratory volume in 0.2 sec (FEV_0.2) to the forced vital capacity, FEV_0.2, dynamic compliance and airway resistance. HDAC2 expression was markedly reduced in the lung tissue of the COPD group compared with the control group, and treatment with Jinwei Tang + budesonide or theophylline + budesonide resulted in significant attenuation of the reduction of HDAC2 expression in the lungs (P<0.05). However, treatment with budesonide alone did not significantly alter HDAC2 expression. In the Jinwei Tang + budesonide and theophylline + budesonide groups, IL-8 and TNF-α expression was significantly decreased (P<0.05) and the HDAC2 level increased (P<0.05) compared with that in the COPD group. In conclusion, Jinwei Tang modulates airway inflammation and may enhance the anti-inflammatory effect of glucocorticoid through the upregulation of HADC2 expression in a rat model of COPD.

High-resolution metabolomics to identify urine biomarkers in corticosteroid-resistant asthmatic children

BACKGROUND

Corticosteroid (CS) treatment has been established as the first anti-inflammatory treatment for adults and children with asthma. However, a subset of patients fails to respond to combined systemic and inhaled CS treatment.

OBJECTIVE

This study was aimed at further understanding CS resistance among children with severe asthma.

METHODS

High-resolution metabolomics was performed on urine samples from CS-respondent (n = 15) and CS-nonrespondent (n = 15) children to determine possible urine biomarkers related to CS resistance. The metabolic phenotypes of CS responders and CS nonresponders were analyzed using bioinformatics including Manhattan plot with false- discovery rate, hierarchical cluster analysis, Kyoto Encyclopedia Genes and Genomes, and Mummichog pathway analysis.

RESULTS

The 2-way hierarchical cluster analysis study determined 30 metabolites showing significantly different levels between CS responders and CS nonresponders. The important metabolites annotated were 3,6-dihydronicotinic acid (126.05 m/z, RT: 106, [M+H]⁺), 3-methoxy-4-hydroxyphenyl(ethylene)glycol (185.05 m/z, RT: 155, [M+H]⁺), 3,4-dihydroxy-phenylalanine (198.07 m/z, RT: 446, [M+H]⁺), γ-glutamylcysteine (236.06 m/z, RT: 528, [M+S(34)+H]⁺), Cys-Gly, (253.06 m/z, RT: 528, [M-NH₃+H]⁺), and reduced Flavin mononucleotide (517.0794 m/z, RT: 533, [M+NaCl]⁺). Tyrosine metabolism, degradation of aromatic compounds, and glutathione metabolism are suggested to be significant pathways relating to CS resistance.

CONCLUSIONS

High-resolution metabolomics is a promising approach in asthma research. Five candidate markers were identified to be related to CS-resistant children with severe asthma. These compounds, upon validation, may contribute further in the understanding of CS resistance among children with severe asthma through the use of urine.

MUC4 impairs the anti-inflammatory effects of corticosteroids in patients with chronic rhinosinusitis with nasal polyps

BACKGROUND

Current evidence suggests that membrane-tethered mucins could mediate corticosteroid efficacy, interacting with glucocorticoid receptor (GR) in patients with chronic rhinosinusitis with nasal polyps (CRSwNP). Mucin 4 (MUC4)-tethered mucin is expressed in nasal polyp (NP) epithelial cells and upregulated under inflammatory conditions. Moreover, MUC4β has the capacity to interact with other intracellular proteins. We hypothesized that MUC4 modulates corticosteroid efficacy of patients with CRSwNP.

OBJECTIVE

We sought to analyze the role of MUC4 in corticosteroid effectiveness in different cohorts of patients with CRSwNP and elucidate the possible mechanisms involved.

METHODS

Eighty-one patients with CRSwNP took oral corticosteroids for 15 days. Corticosteroid resistance was evaluated by using nasal endoscopy. Expression of MUC4 and MUC4β was evaluated by means of real-time PCR, Western blotting, and immunohistochemistry. BEAS-2B knockdown with RNA interference for MUC4 (small interfering RNA [siRNA]-MUC4) was used to analyze the role of MUC4 in the anti-inflammatory effects of dexamethasone.

RESULTS

Twenty-two patients had NPs resistant to oral corticosteroids. MUC4 expression was upregulated in these patients. In siRNA-MUC4 BEAS-2B airway epithelial cells dexamethasone produced higher anti-inflammatory effects, increased inhibition of phospho-extracellular signal-regulated kinase 1/2, increased mitogen-activated protein kinase phosphatase 1 expression, and increased glucocorticoid response element activation. Immunoprecipitation and immunofluorescence experiments revealed that MUC4β forms a complex with GRα in the nuclei of NP epithelial cells from corticosteroid-resistant patients.

CONCLUSION

MUC4β participates in the corticosteroid resistance process, inhibiting normal GRα nuclear function. The high expression of MUC4 in patients with CRSwNP might participate in corticosteroid resistance.

Restoration of Corticosteroid Sensitivity in Chronic Obstructive Pulmonary Disease by Inhibition of Mammalian Target of Rapamycin

RATIONALE

Corticosteroid resistance is a major barrier to the effective treatment of chronic obstructive pulmonary disease (COPD). Several molecular mechanisms have been proposed, such as activations of the phosphoinositide-3-kinase/Akt pathway and p38 mitogen-activated protein kinase. However, the mechanism for corticosteroid resistance is still not fully elucidated.

OBJECTIVES

To investigate the role of mammalian target of rapamycin (mTOR) in corticosteroid sensitivity in COPD.

METHODS

The corticosteroid sensitivity of peripheral blood mononuclear cells collected from patients with COPD, smokers, and nonsmoking control subjects, or of human monocytic U937 cells exposed to cigarette smoke extract (CSE), was quantified as the dexamethasone concentration required to achieve 30% inhibition of tumor necrosis factor-α-induced CXCL8 production in the presence or absence of the mTOR inhibitor rapamycin. mTOR activity was determined as the phosphorylation of p70 S6 kinase, using Western blotting.

MEASUREMENTS AND MAIN RESULTS

mTOR activity was increased in peripheral blood mononuclear cells from patients with COPD, and treatment with rapamycin inhibited this as well as restoring corticosteroid sensitivity. In U937 cells, CSE stimulated mTOR activity and c-Jun expression, but pretreatment with rapamycin inhibited both and also reversed CSE-induced corticosteroid insensitivity.

CONCLUSIONS

mTOR inhibition by rapamycin restores corticosteroid sensitivity via inhibition of c-Jun expression, and thus mTOR is a potential novel therapeutic target for COPD.

Addressing corticosteroid insensitivity in adults with asthma

Corticosteroids are the most effective treatment for asthma, but the therapeutic response varies markedly between individuals, with up to one third of patients showing evidence of insensitivity to corticosteroids. This article summarizes information on genetic, environmental and asthma-related factors as well as demographic and pharmacokinetic variables associated with corticosteroid insensitivity in asthma. Molecular mechanisms proposed to explain corticosteroid insensitivity are reviewed including alterations in glucocorticoid receptor subtype, binding and nuclear translocation, increased proinflammatory transcription factors and defective histone acetylation. Current therapies and future interventions that may restore corticosteroid sensitivity in asthma are discussed, including small molecule drugs and biological agents. In the future, biomarkers may be used in the clinic to predict corticosteroid sensitivity in patients with poorly controlled asthma.

Therapeutic approaches to asthma-chronic obstructive pulmonary disease overlap syndromes

The recognition that there are some patients with features of asthma and chronic obstructive pulmonary disease (COPD) has highlighted the need to develop more specific treatments for these clinical phenotypes. Some patients with COPD have predominantly eosinophilic inflammation and might respond to high doses of inhaled corticosteroids and newly developed specific antieosinophil therapies, including blocking antibodies against IL-5, IL-13, IL-33, and thymic stromal lymphopoietin, as well as oral chemoattractant receptor-homologous molecule expressed on TH2 cells antagonists. Other patients have severe asthma or are asthmatic patients who smoke with features of COPD-induced inflammation and might benefit from treatments targeting neutrophils, including macrolides, CXCR2 antagonists, phosphodiesterase 4 inhibitors, p38 mitogen-activating protein kinase inhibitors, and antibodies against IL-1 and IL-17. Other patients appear to have largely fixed obstruction with little inflammation and might respond to long-acting bronchodilators, including long-acting muscarinic antagonists, to reduce hyperinflation. Highly selected patients with severe asthma might benefit from bronchial thermoplasty. Some patients with overlap syndromes can be conveniently treated with triple fixed-dose combination inhaler therapy with an inhaled corticosteroid, long-acting β2-agonist, and long-acting muscarinic antagonist, several of which are now in development. Corticosteroid resistance is a feature of asthma-COPD overlap syndrome, and understanding the various molecular mechanisms of this resistance has identified novel therapeutic targets and presented the prospect of therapies that can restore corticosteroid responsiveness.

Mucin 1 downregulation associates with corticosteroid resistance in chronic rhinosinusitis with nasal polyps

BACKGROUND

A number of patients with chronic rhinosinusitis with nasal polyps (CRSwNP) are resistant to oral corticosteroids. Mucin 1 (MUC1) shows anti-inflammatory properties, and its cytoplasmic tail (CT) interacts with transcription factors, facilitating their nuclear translocation. Because glucocorticoid receptor (GR) nuclear translocation is key to the anti-inflammatory effect of corticosteroids, we hypothesized that MUC1 is involved in the effectiveness of corticosteroids.

OBJECTIVE

To analyze the role of MUC1 in corticosteroid effectiveness in different cohorts of patients with CRSwNP and elucidate the possible mechanisms involved.

METHODS

Seventy-three patients with CRSwNP took oral corticosteroids for 15 days. Corticosteroid resistance was evaluated by nasal endoscopy. The expression of MUC1 and MUC1 CT was evaluated by real-time PCR, Western blotting, and immunohistochemistry. Beas-2B knockdown with RNA interference for MUC1 (siRNA-MUC1) was used to analyze the role of MUC1 in the anti-inflammatory effects of dexamethasone.

RESULTS

Nineteen patients had nasal polyps that were resistant to oral corticosteroids (NP-CR). MUC1 expression was downregulated in these patients. Primary epithelial cells from patients with NP-CR were insensitive to the anti-inflammatory effects of dexamethasone. In siRNA-MUC1 Beas-2B, dexamethasone showed weaker anti-inflammatory effects, a reduced inhibition of phospho-extracellular-signal-regulated kinases 1/2, a less severe mitogen-activated protein kinase phosphatase 1 increase, and a reduced GR nuclear translocation. Immunoprecipitation experiments revealed that MUC1-CT and GRα form protein complexes and translocate to the nucleus in response to dexamethasone. MUC1-CT-GRα complex was downregulated in NP-CR tissue.

CONCLUSION

MUC1-CT participates in the corticosteroid response that mediates GRα nuclear translocation. The low expression of MUC1 in patients with CRSwNP may participate in corticosteroid resistance.

Roflumilast N-oxide reverses corticosteroid resistance in neutrophils from patients with chronic obstructive pulmonary disease

BACKGROUND

Glucocorticoid functions are markedly impaired in patients with chronic obstructive pulmonary disease (COPD). The phosphodiesterase 4 inhibitor roflumilast N-oxide (RNO) is the active metabolite of roflumilast approved as a treatment to reduce the risk of exacerbations in patients with severe COPD.

OBJECTIVE

We sought to characterize the differential effects of RNO versus corticosteroids and their potential additive/synergistic effect in neutrophils from patients with COPD, thus providing scientific rationale for the combination of roflumilast with corticosteroids in the clinic.

METHODS

Peripheral blood neutrophils were isolated from patients with COPD (n = 32), smokers (n = 7), and healthy nonsmokers (n = 25). Levels of IL-8, matrix metallopeptidase 9 (MMP-9), and biomarkers of glucocorticoid resistance were determined by using ELISA and RT-PCR. Neutrophils were incubated with dexamethasone (0.1 nmol/L to 1 μmol/L), RNO (0.1 nmol/L to 1 μmol/L), or the combination of 1 nmol/L RNO plus 10 nmol/L DEX and stimulated with LPS (1 μg/mL) or cigarette smoke extract 5%; levels of IL-8, MMP-9, and other biomarkers were measured at the end of the incubation period.

RESULTS

Peripheral neutrophils from patients with COPD showed a primed phenotype with an increased basal release of IL-8 and MMP-9 and expressed a corticosteroid resistance molecular profile characterized by an increase in phosphoinositide 3-kinase δ, macrophage migration inhibitory factor, and glucocorticoid receptor β expression and a decrease in HDAC activity and mitogen-activated protein kinase phosphatase 1 expression. RNO demonstrated robust anti-inflammatory effects on neutrophils from patients with COPD, reversing their resistance to corticosteroids. The combination of RNO and dexamethasone showed additive/synergistic effects, which were consistent with the reversal of corticosteroid-resistant molecular markers by RNO.

CONCLUSION

RNO reverses corticosteroid resistance and shows strong anti-inflammatory effects alone or in combination with corticosteroids on neutrophils from patients with COPD.