Eotaxin-2 in sputum cell culture to evaluate asthma inflammation

Single-cell transcriptomics delineates the immune cell landscape in equine lower airways and reveals upregulation of FKBP5 in horses with asthma

Equine asthma (EA) is a heterogenous, complex disease, with a significant negative impact on horse welfare and performance. EA and human asthma share fundamental similarities, making EA a useful model for studying the disease. One relevant sample type for investigating chronic lung inflammation is bronchoalveolar lavage fluid (BALF), which provides a snapshot of the immune cells present in the alveolar space. To investigate the immune cell landscape of the respiratory tract in horses with mild-to-moderate equine asthma (mEA) and healthy controls, single-cell RNA sequencing was conducted on equine BALF cells. We characterized the major immune cell populations present in equine BALF, as well as subtypes thereof. Interestingly, the most significantly upregulated gene discovered in cases of mEA was FKBP5, a chaperone protein involved in regulating the activity of the glucocorticoid receptor.

Modulation of blood inflammatory markers by benralizumab in patients with eosinophilic airway diseases

Background

Benralizumab, a humanized, afucosylated, monoclonal antibody that targets interleukin-5 receptor α, depletes eosinophils and basophils by enhanced antibody-dependent cell-mediated cytotoxicity. It demonstrated efficacy for patients with moderate to severe asthma and, in a Phase IIa trial, for chronic obstructive pulmonary disease (COPD) with eosinophilic inflammation. We investigated effects of benralizumab 100 mg every 8 weeks (first three doses every 4 weeks) subcutaneous on blood inflammatory markers through proteomic and gene-expression analyses collected during two Phase II studies of patients with eosinophilic asthma and eosinophilic COPD.

Methods

Serum samples for proteomic analysis and whole blood for gene expression analysis were collected at baseline and 52 weeks (asthma study) or 32 weeks (COPD study) post-treatment. Proteomic analyses were conducted on a custom set of 90 and 147 Rules-Based Medicine analytes for asthma and COPD, respectively. Gene expression was profiled by Affymetrix Human Genome U133 plus 2 arrays (~ 54 K probes). Gene set variation analysis (GSVA) was used to determine transcriptomic activity of immune signatures. Treatment-related differences between analytes, genes, and gene signatures were analyzed for the overall population and for patient subgroups stratified by baseline blood eosinophil count (eosinophil-high [≥300 cells/μL] and eosinophil-low [< 300 cells/μL]) via t-test and repeated measures analysis of variance.

Results

Eosinophil chemokines eotaxin-1 and eotaxin-2 were significantly upregulated (false discovery rate [FDR] < 0.05) by approximately 2.1- and 1.4-fold in the asthma study and by 2.3- and 1.7-fold in the COPD study following benralizumab treatment. Magnitude of upregulation of these two chemokines was greater for eosinophil-high patients than eosinophil-low patients in both studies. Benralizumab was associated with significant reductions (FDR < 0.05) in expression of genes associated with eosinophils and basophils, such as CLC, IL-5Rα, and PRSS33; immune-signaling complex genes (FCER1A); G-protein–coupled receptor genes (HRH4, ADORA3, P2RY14); and further immune-related genes (ALOX15 and OLIG2). The magnitude of downregulation of gene expression was greater for eosinophil-high than eosinophil-low patients. GSVA on immune signatures indicated significant treatment reductions (FDR < 0.05) in eosinophil-associated signatures.

Conclusions

Benralizumab is highly selective, modulating blood proteins or genes associated with eosinophils or basophils. Modulated protein and gene expression patterns are most prominently altered in eosinophil-high vs. eosinophil-low patients.

Trial registration

NCT01227278 and NCT01238861.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0968-8) contains supplementary material, which is available to authorized users.

Regulation of Eosinophil and Group 2 Innate Lymphoid Cell Trafficking in Asthma

Asthma is an inflammatory disease usually characterized by increased Type 2 cytokines and by an infiltration of eosinophils to the airways. While the production of Type 2 cytokines has been associated with T_H2 lymphocytes, increasing evidence indicates that group 2 innate lymphoid cells (ILC2) play an important role in the production of the Type 2 cytokines interleukin (IL)-5 and IL-13, which likely amplifies the recruitment of eosinophils from the blood to the airways. In that regard, recent asthma treatments have been focusing on blocking Type 2 cytokines, notably IL-4, IL-5, and IL-13. These treatments mainly result in decreased blood or sputum eosinophil counts as well as decreased asthma symptoms. This supports that therapies blocking eosinophil recruitment and activation are valuable tools in the management of asthma and its severity. Herein, we review the mechanisms involved in eosinophil and ILC2 recruitment to the airways, with an emphasis on eotaxins, other chemokines as well as their receptors. We also discuss the involvement of other chemoattractants, notably the bioactive lipids 5-oxo-eicosatetraenoic acid, prostaglandin D₂, and 2-arachidonoyl-glycerol. Given that eosinophil biology differs between human and mice, we also highlight and discuss their responsiveness toward the different eosinophil chemoattractants.

Efficacy of Rhesus Theta-Defensin-1 in Experimental Models of Pseudomonas aeruginosa Lung Infection and Inflammation

Chronic airway infection and inflammation contribute to the progressive loss of lung function and shortened survival of patients with cystic fibrosis (CF). Rhesus theta defensin-1 (RTD-1) is a macrocyclic host defense peptide with antimicrobial and immunomodulatory activities. Combined with favorable preclinical safety and peptide stability data, RTD-1 warrants investigation to determine its therapeutic potential for treatment of CF lung disease. We sought to evaluate the therapeutic potential of RTD-1 for CF airway infection and inflammation using in vitro, ex vivo, and in vivo models. We evaluated RTD-1's effects on basal and Pseudomonas aeruginosa-induced inflammation in CF sputum leukocytes and CF bronchial epithelial cells. Peptide stability was evaluated by incubation with CF sputum. Airway pharmacokinetics, safety, and tolerance studies were performed in naive mice. Aerosolized RTD-1 treatment effects were assessed by analyzing lung bacterial burdens and airway inflammation using an established model of chronic P. aeruginosa endobronchial infection in CF (ΔF508) mice. RTD-1 directly reduces metalloprotease activity, as well as inflammatory cytokine secretion from CF airway leukocyte and bronchial epithelial cells. Intrapulmonary safety, tolerability, and stability data support the aerosol administration route. RTD-1 reduced the bacterial lung burden, airway neutrophils, and inflammatory cytokines in CF mice with chronic P. aeruginosa lung infection. Collectively, these studies support further development of RTD-1 for treatment of CF airway disease.

Deciphering Asthma Biomarkers with Protein Profiling Technology

Asthma is a chronic inflammatory disease of the airways, resulting in bronchial hyperresponsiveness with every allergen exposure. It is now clear that asthma is not a single disease, but rather a multifaceted syndrome that results from a variety of biologic mechanisms. Asthma is further problematic given that the disease consists of many variants, each with its own etiologic and pathophysiologic factors, including different cellular responses and inflammatory phenotypes. These facets make the rapid and accurate diagnosis (not to mention treatments) of asthma extremely difficult. Protein biomarkers can serve as powerful detection tools in both clinical and basic research applications. Recent endeavors from biomedical researchers have developed technical platforms, such as cytokine antibody arrays, that have been employed and used to further the global analysis of asthma biomarker studies. In this review, we discuss potential asthma biomarkers involved in the pathophysiologic process and eventual pathogenesis of asthma, how these biomarkers are being utilized, and how further testing methods might help improve the diagnosis and treatment strain that current asthma patients suffer.

Effects of prednisone on eosinophilic bronchitis in asthma: a systematic review and meta-analysis

OBJECTIVE:

To evaluate the effect size of oral corticosteroid treatment on eosinophilic bronchitis in asthma, through systematic review and meta-analysis.

METHODS:

We systematically reviewed articles in the Medline, Cochrane Controlled Trials Register, EMBASE, and LILACS databases. We selected studies meeting the following criteria: comparing at least two groups or time points (prednisone vs. control, prednisone vs. another drug, or pre- vs. post-treatment with prednisone); and evaluating parameters before and after prednisone use, including values for sputum eosinophils, sputum eosinophil cationic protein (ECP), and sputum IL-5-with or without values for post-bronchodilator FEV₁-with corresponding 95% CIs or with sufficient data for calculation. The independent variables were the use, dose, and duration of prednisone treatment. The outcomes evaluated were sputum eosinophils, IL-5, and ECP, as well as post-bronchodilator FEV₁.

RESULTS:

The pooled analysis of the pre- vs. post-treatment data revealed a significant mean reduction in sputum eosinophils (↓8.18%; 95% CI: 7.69-8.67; p < 0.001), sputum IL-5 (↓83.64 pg/mL; 95% CI: 52.45-114.83; p < 0.001), and sputum ECP (↓267.60 µg/L; 95% CI: 244.57-290.63; p < 0.0001), as well as a significant mean increase in post-bronchodilator FEV₁ (↑8.09%; 95% CI: 5.35-10.83; p < 0.001).

CONCLUSIONS:

In patients with moderate-to-severe eosinophilic bronchitis, treatment with prednisone caused a significant reduction in sputum eosinophil counts, as well as in the sputum levels of IL-5 and ECP. This reduction in the inflammatory response was accompanied by a significant increase in post-bronchodilator FEV₁.

Metabolic disease risk in children by salivary biomarker analysis

Objective

The study of obesity-related metabolic syndrome or Type 2 diabetes (T2D) in children is particularly difficult because of fear of needles. We tested a non-invasive approach to study inflammatory parameters in an at-risk population of children to provide proof-of-principle for future investigations of vulnerable subjects.

Design and Methods

We evaluated metabolic differences in 744, 11-year old children selected from underweight, normal healthy weight, overweight and obese categories by analyzing fasting saliva samples for 20 biomarkers. Saliva supernatants were obtained following centrifugation and used for analyses.

Results

Salivary C-reactive protein (CRP) was 6 times higher, salivary insulin and leptin were 3 times higher, and adiponectin was 30% lower in obese children compared to healthy normal weight children (all P<0.0001). Categorical analysis suggested that there might be three types of obesity in children. Distinctly inflammatory characteristics appeared in 76% of obese children while in 13%, salivary insulin was high but not associated with inflammatory mediators. The remaining 11% of obese children had high insulin and reduced adiponectin. Forty percent of the non-obese children were found in groups which, based on biomarker characteristics, may be at risk for becoming obese.

Conclusions

Significantly altered levels of salivary biomarkers in obese children from a high-risk population, suggest the potential for developing non-invasive screening procedures to identify T2D-vulnerable individuals and a means to test preventative strategies.

Fast beneficial systemic anti-inflammatory effects of inhaled budesonide and formoterol on circulating lymphocytes in asthma

BACKGROUND AND OBJECTIVE

Inhaled glucocorticoids and long acting β2 -agonists reduce airway inflammation. It is unclear if this effect is based on the local action of the drugs or is due to a systemic effect on circulating peripheral blood lymphocytes. We assessed whether inhaled budesonide and/or formoterol modify the activity of circulating peripheral blood lymphocytes.

METHODS

Placebo controlled crossover design, including healthy (n = 10) or mild asthmatic males (n = 8). Blood was collected in the morning at 08:00 before drug inhalation, and drugs (placebo, budesonide 400 μg, formoterol 12 μg) were inhaled alone or in combination at 08:30. Four more blood samples were collected after inhalation at 09:00, 09:30, 12:30 and at 09:30 am on the following day. The activity of the glucocorticoid receptor, NFκB and IκB was determined in isolated lymphocytes. Lymphocytes were stimulated with lipopolysaccharide (LPS 10 μg/mL) for 24 h and interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF)-α, eotaxin level were determined. Lymphocyte proliferation was induced by phytohaemagglutinin (PHA 10 μg/mL) over 24 h.

RESULTS

When combined, the drugs synergistically activated the glucocorticoid receptor within 30 min but did not modify NFκB or IκB activity. Inhaled budesonide significantly reduced LPS-induced IL-1β, IL-6, IL-8 and TNF-α secretion, while inhaled formoterol had no such effect; however when combined, the inhibitory effect of budesonide was significantly increased by formoterol. PHA-induced proliferation was reduced by both drugs alone and in combination.

CONCLUSIONS

Combined budesonide and formoterol may reduce airway inflammation and immune reactivity of circulating lymphocytes through its local and systemic effects.

Epithelial eotaxin-2 and eotaxin-3 expression: relation to asthma severity, luminal eosinophilia and age at onset

BACKGROUND

Eosinophilic inflammation is implicated in asthma. Eotaxin 1-3 regulate eosinophil trafficking into the airways along with other chemotactic factors. However, the epithelial and bronchoalveolar lavage (BAL) cell expression of these chemokines in relation to asthma severity and eosinophilic phenotypes has not been addressed.

OBJECTIVE

To measure the expression of the three eotaxin isoforms in bronchoscopically obtained samples and compare them with clinically relevant parameters between normal subjects and patients with asthma.

METHODS

Normal subjects and patients with asthma of varying severity recruited through the Severe Asthma Research Program underwent clinical assessment and bronchoscopy with airway brushing and BAL. Eotaxin 1-3 mRNA/protein were measured in epithelial and BAL cells and compared with asthma severity, control and eosinophilic inflammation.

RESULTS

Eotaxin-2 and eotaxin-3 mRNA and eotaxin-2 protein were increased in airway epithelial brushings from patients with asthma and were highest in cases of severe asthma (p values 0.0155, 0.0033 and 0.0006, respectively), with eotaxin-2 protein increased with age at onset. BAL cells normally expressed high levels of eotaxin-2 mRNA/protein but BAL fluid levels of eotaxin-2 were lowest in severe asthma. Epithelial eotaxin-2 and eotaxin-3 mRNA/protein was associated with sputum eosinophilia, lower forced expiratory volume in 1 s and more asthma exacerbations. Airway epithelial cell eotaxin-2 protein differed by asthma severity only in those with late onset disease, and tended to be highest in those with late onset eosinophilic asthma.

CONCLUSIONS

Epithelial eotaxin-2 and 3 are increased in asthma and severe asthma. Their expression may contribute to luminal migration of eosinophils, especially in later onset disease, asthma control and severity.

Eosinophil degranulation is more important than eosinophilia in identifying asthma in chronic cough

OBJECTIVE

We investigated whether eosinophil degranulation is a distinctive feature of asthma and can distinguish between chronic cough patients with asthma and those without.

METHODS

Thirty-seven patients, with a chronic cough for more than 1 month, and nine normal individuals (controls) were enrolled. Subjects were divided into two groups: one group with asthma and positive bronchial hyperresponsiveness (BHR) (Asthma group, n = 18) and the other group without asthma and negative BHR (Non-Asthma group, n = 19). From induced sputum, total cell counts and differentials were determined. Myeloperoxidase levels were measured by Enzyme-Linked Immunosorbent Assay (ELISA), and eosinophil-derived neurotoxin (EDN) and major basic protein (MBP) levels were measured by radioimmunoassay.

RESULTS

The percentage of sputum eosinophils was increased in the Asthma (p < .001) and Non-Asthma (p < .05) groups compared with the Control group and when comparing the Asthma and Non-Asthma (p < .001) groups. Sputum EDN and MBP levels were increased in the Asthma group compared with the Non-Asthma (p < .05 and p < .05, respectively) and Control groups (p < .05 and p = .055, respectively). However, EDN and MBP levels were not increased in the Non-Asthma group compared with the Control group. The percentage of sputum eosinophils in the Asthma group correlated positively with sputum EDN (Rs = 0.921, p < .001) and MBP (Rs = 0.882, p < .0001) levels and negatively with maxΔFEV(1) (Rs = -0.501, p < .05) (FEV(1), forced expiratory volume in 1 second). Unexpectedly, the percentage of eosinophils in the Non-Asthma group did not correlate significantly with any of these markers. Increased EDN and MBP levels and significant correlations between the percentage of eosinophils and EDN and MBP were only observed in asthma patients.

CONCLUSIONS

These findings suggest that eosinophil degranulation is more important than eosinophilia in identifying asthma.

The roles of a Th2 cytokine and CC chemokine in children with stable asthma: potential implication in eosinophil degranulation

Th2 cytokine IL-5 and CC chemokine eotaxin are thought to be key regulators of eosinophils in bronchial asthma. However, their involvement in children with stable asthma (SA) has not been determined. We investigated the roles of IL-5 and eotaxin in eosinophil degranulation in children with SA. Induced sputum was obtained from 30 SA, 21 allergic rhinitis (AR), and 22 non-atopic healthy control (HC) children. We measured sputum levels of IL-5, eotaxin, and eosinophil indices [percentage eosinophils, eosinophil-derived neurotoxin (EDN), and eosinophil-cationic protein (ECP)]. We also examined correlations of IL-5 and eotaxin with eosinophil indices. Sputum percentage eosinophils and EDN and ECP levels were significantly higher in the SA group than in the HC group, while only the sputum EDN and ECP levels were significantly higher in the AR group than in the HC group. Unexpectedly, sputum levels of IL-5 were not significantly different among the three groups; however, the levels of eotaxin were higher in the SA group when compared to the HC group. No significant correlations were found between IL-5 and percentage eosinophils, EDN, or ECP levels; in contrast, eotaxin levels correlated significantly with percentage eosinophils (R(s) = 0.638; p = 0.0001), EDN (R(s) = 0.522; p = 0.003), and ECP levels (R(s) = 0.630 and p = 0.0002). The elevated levels and good correlations of eotaxin with sputum eosinophil indices, and no elevation or correlation of IL-5 with these indices, suggest that CC chemokine eotaxin may play a more important role in eosinophil degranulation in children with SA.

Protein microarray analysis in patients with asthma: elevation of the chemokine PARC/CCL18 in sputum

BACKGROUND

Microarray technology offers a new opportunity to gain insight into global gene and protein expression profiles in asthma. To identify novel factors produced in the asthmatic airway, we analyzed sputum samples by using a membrane-based human cytokine microarray technology in patients with bronchial asthma (BA).

METHODS

Induced sputum was obtained from 28 BA subjects, 20 nonasthmatic atopic control (AC) subjects, and 38 nonasthmatic nonatopic normal control (NC) subjects. The microarray samples of subjects were randomly selected from nine BA subjects, three AC subjects, and six NC subjects. Sputum supernatants were analyzed using a custom human cytokine array (RayBio Custom Human Cytokine Array; RayBiotech; Norcross, GA) designed to analyze 79 specific cytokines simultaneously. The levels of growth-regulated oncogene (GRO)-alpha, eotaxin-2, and pulmonary and activation-regulated chemokine (PARC)/CCL18 were measured by sandwich enzyme-linked immunosorbent assays (ELISAs), and eosinophil-derived neurotoxin (EDN) was measured by radioimmunoassay.

RESULTS

By microarray, the signal intensities for GRO-alpha, eotaxin-2, and PARC were significantly higher in BA subjects than in AC and NC subjects (p = 0.036, p = 0.042, and p = 0.033, respectively). By ELISA, the sputum PARC protein levels were significantly higher in BA subjects than in AC and NC subjects (p < 0.0001). Furthermore, PARC levels correlated significantly with sputum eosinophil percentages (r = 0.570, p < 0.0001) and the levels of EDN (r = 0.633, p < 0.0001), the regulated upon activation, normal T cell expressed and secreted cytokine (r = 0.440, p < 0.001), interleukin-4 (r = 0.415, p < 0.01), and interferon-gamma (r = 0.491, p < 0.001).

CONCLUSIONS

By a nonbiased screening approach, a chemokine, PARC, is elevated in sputum specimens from patients with asthma. PARC may play important roles in development of airway eosinophilic inflammation in asthma.

Inflammatory and functional effects of increasing asthma treatment with formoterol or double dose budesonide

Adding a long-acting beta(2)-agonist to inhaled corticosteroids (ICS) for asthma treatment is better than increasing ICS dose in improving clinical status, although there is no consensus about the impact of this regimen on inflammation. In this double-blind, randomized, parallel group study, asthmatics with moderate to severe disease used budesonide (400 mcg/day) for 5 weeks (run-in period); then they were randomized to use budesonide (800 mcg/day--BUD group) or budesonide plus formoterol (400 mcg and 24 mcg/day, respectively--FORMO group) for 9 weeks (treatment period). Home PEF measurements, symptom daily reporting, spirometry, sputum induction (for differential cell counts and sputum cell cultures), and hypertonic saline bronchial challenge test were performed before and after treatments. TNF-alpha, IL-4 and eotaxin-2 levels in the sputum and cell culture supernatants were determined. Morning and night PEF values increased in the FORMO group during the treatment period (p<0.01), from 435+/-162 to 489+/-169 and 428+/-160 to 496+/-173 L/min, respectively. The rate of exacerbations in the FORMO group was lower than in the BUD group (p<0.05). Neutrophil counts in sputum increased in both groups (p<0.05) and leukocyte viability after 48 h-culture increased in the FORMO group (p<0.05). No other parameter changed significantly in either group. This study showed that adding formoterol to budesonide improved home PEF and provided protection from exacerbations, although increase of leukocyte viability in cell culture may be a matter of concern and needs further investigation.