Search Results (9)

Unripe Rubus occidentalis (uRO) contains various natural polyphenols with beneficial physiological activities and is particularly rich in ellagic acid (EA). EA has ameliorated type 2 inflammation and airway hyperresponsiveness in animal models of eosinophilic asthma. EA is metabolized by the gut microbiota to urolithin A (UA), which exhibits anti-inflammatory properties. However, it remains unclear whether uRO, EA, and UA reduce inflammatory responses and oxidative stress in respiratory epithelial cells and neutrophils. In this study, inflammation was induced in A549 (human lung epithelial cells) and dHL-60 cells (neutrophil-like cells differentiated from human promyelocytic leukemia HL-60 cells) and treated with various concentrations of water extract of uRO (uRO-w), EA, and UA. EA, uRO-w and UA suppressed the inflammatory cytokine and chemokine levels and reduced the expression of matrix metalloproteinase-9 in A549 cells stimulated with IL-1β. As a result of analyzing the mechanism by which these inflammatory molecules are expressed, it was found that EA, uRO-w, and UA regulated corticosteroid-sensitive mitogen activated protein kinase, nuclear factor κB, and corticosteroid-insensitive AKT. In addition, uRO-w, EA, and UA significantly reduced reactive oxygen species levels in phorbol 12-myristate 13-acetate-stimulated dHL-60 cells and inhibited neutrophil extracellular trap formation. Therefore, our results suggest that uRO-w, EA, and UA are potential therapeutic agents for preventing and treating inflammatory respiratory diseases. Full article

Asthma in elderly populations is an increasing health problem that is accompanied by diminished lung function and frequent exacerbations. As potent anti-inflammatory drugs, corticosteroids are commonly used to reduce lung inflammation, improve lung function, and manage disease symptoms in asthma. Although effective for most individuals, older patients are more insensitive to corticosteroids, making it difficult to manage asthma in this population. With the number of individuals older than 65 continuing to increase, it is important to understand the distinct mechanisms that promote corticosteroid insensitivity in the aging lung. In this review, we discuss corticosteroid insensitivity in asthma with an emphasis on mechanisms that contribute to persistent inflammation and diminished lung function in older individuals. Full article

Once COPD is established, pulmonary lesions can only progress and smoking cessation by itself is not sufficient to switch off persistent lung inflammation. Similarly, in former-smoker mice, neutrophil inflammation persists and lung lesions undergo progressive deterioration. The molecular mechanisms underlying disease progression and the inefficiency of smoking cessation in quenching neutrophilic inflammation were studied in male C57 Bl/6 mice after 6 months of rest from smoking cessation. As compared with the mice that continued to smoke, the former-smoker mice showed reduced expression of histone deacetylases HDAC2 and SIRT1 and marked expression of p-p38 MAPK and p-Ser10. All these factors are involved in corticosteroid insensitivity and in perpetuating inflammation. Former-smoker mice do show persistent lung neutrophilic influx and a high number of macrophages which account for the intense staining in the alveolar structures of neutrophil elastase and MMP-9 (capable of destroying lung scaffolding) and 8-OHdG (marker of oxidative stress). “Alarmins” released from necrotic cells together with these factors can sustain and perpetuate inflammation after smoking cessation. Several factors and mechanisms all together are involved in sustaining and perpetuating inflammation in former-smoker mice. This study suggests that a better control of COPD in humans may be achieved by precise targeting of the various molecular mechanisms associated with different phenotypes of disease by using a cocktail of drug active toward specific molecules. Full article

Mucormycosis is a highly aggressive angio-invasive disease of humans caused by fungi in the zygomycete order, Mucorales. Though a number of different species can cause mucormycosis, the principal agent of the disease worldwide is Rhizopus arrhizus, which accounts for the majority of rhino-orbital-cerebral, pulmonary, and disseminated infections in immunocompromised individuals. It is also the main cause of life-threatening infections in patients with poorly controlled diabetes mellitus, and in corticosteroid-treated patients with SARS-CoV-2 infection, where it causes the newly described disease, COVID-19-associated mucormycosis (CAM). Diagnosis currently relies on non-specific CT, a lengthy and insensitive culture from invasive biopsy, and a time-consuming histopathology of tissue samples. At present, there are no rapid antigen tests for the disease that detect biomarkers of infection, and which allow point-of-care diagnosis. Here, we report the development of an IgG1 monoclonal antibody (mAb), KC9, which is specific to Rhizopus arrhizus var. arrhizus (syn. Rhizopus oryzae) and Rhizopus arrhizus var. delemar (Rhizopus delemar), and which binds to a 15 kDa extracellular polysaccharide (EPS) antigen secreted during hyphal growth of the pathogen. Using the mAb, we have developed a competitive lateral-flow device (LFD) that allows rapid (30 min) and sensitive (~50 ng/mL running buffer) detection of the EPS biomarker, and which is compatible with human serum (limit of detection of ~500 ng/mL) and bronchoalveolar lavage fluid (limit of detection of ~100 ng/mL). The LFD, therefore, provides a potential novel opportunity for the non-invasive detection of mucormycosis caused by Rhizopus arrhizus. Full article

Corticosteroid insensitivity is a key characteristic of patients with severe asthma and COPD. These individuals experience greater pulmonary oxidative stress and inflammation, which contribute to diminished lung function and frequent exacerbations despite the often and prolonged use of systemic, high dose corticosteroids. Reactive oxygen and nitrogen species (RONS) promote corticosteroid insensitivity by disrupting glucocorticoid receptor (GR) signaling, leading to the sustained activation of pro-inflammatory pathways in immune and airway structural cells. Studies in asthma and COPD models suggest that corticosteroids need a balanced redox environment to be effective and to reduce airway inflammation. In this review, we discuss how oxidative stress contributes to corticosteroid insensitivity and the importance of optimizing endogenous antioxidant responses to enhance corticosteroid sensitivity. Future studies should aim to identify how antioxidant-based therapies can complement corticosteroids to reduce the need for prolonged high dose regimens in patients with severe asthma and COPD. Full article

Eosinophilic chronic rhinosinusitis (ECRS), which is a subgroup of chronic rhinosinusitis with nasal polyps, is characterized by eosinophilic airway inflammation extending across both the upper and lower airways. Some severe cases are refractory even after endoscopic sinus surgery, likely because of local steroid insensitivity. Although real-life studies indicate that treatment with omalizumab for severe allergic asthma improves the outcome of coexistent ECRS, the underlying mechanisms of omalizumab in eosinophilic airway inflammation have not been fully elucidated. Twenty-five patients with ECRS and severe asthma who were refractory to conventional treatments and who received omalizumab were evaluated. Nineteen of twenty-five patients were responsive to omalizumab according to physician-assessed global evaluation of treatment effectiveness. In the responders, the levels of peripheral blood eosinophils and fractionated exhaled nitric oxide (a marker of eosinophilic inflammation) and of CCL4 and soluble CD69 (markers of eosinophil activation) were reduced concomitantly with the restoration of corticosteroid sensitivity. Omalizumab restored the eosinophil-peroxidase-mediated PP2A inactivation and steroid insensitivity in BEAS-2B. In addition, the local inflammation simulant model using BEAS-2B cells incubated with diluted serum from each patient confirmed omalizumab’s effects on restoration of corticosteroid sensitivity via PP2A activation; thus, omalizumab could be a promising therapeutic option for refractory eosinophilic airway inflammation with corticosteroid resistance. Full article

Eosinophilic chronic rhinosinusitis (ECRS), a subgroup of chronic rhinosinusitis with nasal polyps, is recognized as a refractory eosinophilic disorder characterized by both upper and lower airway inflammation. In some severe cases, disease control is poor, likely due to local steroid insensitivity. In this study, we focused on protein phosphatase 2A (PP2A), a key factor regulating glucocorticoid receptor (GR) nuclear translocation, and examined its association with local responses to corticosteroids in eosinophilic airway inflammation. Our results indicated reduced responses to corticosteroids in nasal epithelial cells from ECRS patients with asthma, which were also associated with decreased PP2A mRNA expression. Eosinophil peroxidase stimulates elevated PP2A phosphorylation levels, reducing PP2A protein expression and activity. In addition, mRNA levels of inflammatory mediators (TSLP, IL-25, IL-33, CCL4, CCL5, CCL11, and CCL26) associated with eosinophilic airway inflammation in epithelial cells were increased in nasal polyps (eosinophil-rich areas) compared with those in uncinate process tissues (eosinophil-poor areas) from the same patients. PP2A reduction by siRNA reduced GR nuclear translocation, whereas PP2A overexpression by plasmid transfection, or PP2A activation by formoterol, enhanced GR nuclear translocation. Collectively, our findings indicate that PP2A may represent a promising therapeutic target in refractory eosinophilic airway inflammation characterized by local steroid insensitivity. Full article

Medications for asthma management consisting of inhaled corticosteroids act by controlling symptoms. However, some patients do not respond to steroid treatment due to immunological factors at the cytokine level. Chlamydia pneumoniae (C. pneumoniae) infection is strongly implicated in asthma pathogenesis, causing altered immune responses. We investigated the association of C. pneumoniae serostatus with the production of certain cytokines by peripheral blood mononuclear cells (PBMCs) of steroid-resistant and -sensitive asthmatic patients. Our most important findings are the following: In the case of C. pneumoniae seropositive patients we detected pronounced spontaneous interleukin (IL)-10 secretion and, in the case of steroid-resistant patients, IL-10 secretion was at a significantly higher level as compared with in-sensitive patients (p < 0.01). Furthermore, steroid-resistant seropositive patients produced a significantly higher level of IL-10 spontaneously and under antigen stimulation as compared with steroid-resistant seronegative individuals (p < 0.05). Concerning spontaneous TNF-α secretion by C. pneumoniae seropositive asthmatics, we observed that steroid-resistant patients produced significantly more of this cytokine than steroid-sensitive patients. In the steroid-resistant patients’ sera, a remarkably high MMP-9 concentration was associated with C. pneumoniae seronegativity. Our study revealed that the differences in the cytokine production in steroid-sensitive and -resistant asthmatic patients can be influenced by their C. pneumoniae serostatus. Full article

Airway inflammation in chronic obstructive pulmonary disease (COPD) is partially insensitive/resistant to inhaled corticosteroids (ICS). ICS plus bronchodilator therapy has been discussed for COPD phenotypes with frequent exacerbations and participation of corticosteroid-sensitive type 2/eosinophilic inflammation. Neutralization of non-type 2/IL-8-associated airway inflammation by reversion of its corticosteroid-resistance might be a future strategy for other phenotypes. Human airway smooth muscle cells (HASMCs) produce corticosteroid-insensitive IL-8 in response to TNFα or LPS in stable disease stages or bacteria-induced exacerbations, respectively. p38-mitogen-activated-protein-kinases (p38MAPKs) are alternative therapeutic targets. Hypothesis: long-acting-β2-agonists (LABAs) reverse the corticosteroid-insensitivity of IL-8 by p38MAPK inhibition in HASMCs. Cultivated HASMCs from COPD subjects were pre-incubated with formoterol, salmeterol, fluticasone-propionate, BIRB796 (p38MAPKα, -γ, -δ inhibitor), and/or SB203580 (p38MAPKα and -β inhibitor) before stimulation with TNFα or LPS. IL-8 and MAPK-activities were measured by ELISA. Formoterol, salmeterol, and fluticasone did not or hardly reduced TNFα- or LPS-induced IL-8. BIRB796 and SB203580 reduced TNFα-induced IL-8. SB203580 reduced LPS-induced IL-8. Fluticasone/formoterol, fluticasone/salmeterol, and fluticasone/BIRB796, but not fluticasone/SB203580 combinations, reduced TNFα-induced IL-8 stronger than single treatments. All combinations including fluticasone/SB203580 reduced LPS-induced IL-8 stronger than single treatments. TNFα induced p38MAPKα and -γ activity. LPS induced p38MAPKα activity. Formoterol reduced TNFα-induced p38MAPKγ and LPS-induced p38MAPKα activity. LABAs reverse the corticosteroid-insensitivity of IL-8 in airway smooth muscles via p38MAPKγ in stable disease and via p38MAPKα in exacerbations. Our pre-clinical data indicate a utility for also adding ICS in non-type 2 inflammatory COPD phenotypes to bronchodilator therapy. Depending on phenotype and disease stage, isoform-specific p38MAPK blockers might also reverse corticosteroid-resistance in COPD. Full article