Possible role of HE4 level elevation in the pathogenesis of TH2-high asthma

OBJECTIVES

As a heterogeneous disease, asthma is characterized by airway hyperresponsiveness, airway inflammation, and airway mucus hypersecretion. According to the pathological changes, symptoms, preventive and treatment methods, asthma can be divided into TH2-high and TH2-low asthma. We show that the expression of the tumor biomarker human epididymis protein 4 (HE4) was significantly increased in TH2-high asthma group, while there was no marked difference in its expression between TH2-low asthma and healthy control groups. HE4 levels were significantly increased in plasma, induced sputum, and alveolar lavage fluid (BALF) samples and airway epithelial cells from TH2-high asthma group, showing that HE4 has a possible role in the pathogenesis of TH2-high asthma.

METHODS

Using RT-qPCR, ELISA, Western blot (WB), and immunohistochemistry, we assessed differences in HE4 expression in plasma, induced sputum, BALF, and airway epithelial cells among patients with the TH2-related asthma subtypes and healthy controls. To explore the role of HE4 in TH2-high asthma, we conducted a correlation analysis between HE4 levels in plasma, induced sputum, BALF, and airway epithelial cells and multiple indicators of airway eosinophilic inflammation, airway mucus secretion, and airway remodeling.

CONCLUSION

We found for the first time that HE4 was differentially expressed in the TH2-related asthma subtypes. In TH2-high asthma, HE4 levels were markedly elevated in airway epithelial cells, plasma, induced sputum, and BALF. HE4 may play an important role in various pathogenic mechanisms of asthma, such as airway eosinophilic inflammation, airway mucus secretion, and airway remodeling. HE4 in plasma may be a clinically biomarker for differentiating TH2-related asthma subtypes.

Increased expression of CSF1 in patients with eosinophilic asthma

BACKGROUND

The link between colony-stimulating factor 1 (CSF1) and asthma was reported recently. However, the role and mechanism of CSF1 in asthma remain poorly understood. In this study, we aimed to explore the expression and its potential mechanism of CSF1 in asthma.

METHODS

CSF1 expression in the airway samples from asthmatics and healthy controls were examined, then the correlations between CSF1 and eosinophilic indicators were analyzed. Subsequently, bronchial epithelial cells (BEAS-2B) with CSF1 overexpression and knockdown were constructed to investigate the potential molecular mechanism of CSF1. Finally, the effect of CSF1R inhibitor on STAT1 was investigated.

RESULTS

The expression of CSF1 was significantly increased in patients with asthma compared to healthy controls, especially in patients with severe and eosinophilic asthma. Upregulated CSF1 positively correlated with airway-increased eosinophil inflammation. In vitro, cytokines interleukin 13 (IL-13) and IL-33 can stimulate the upregulation of CSF1 expression. CSF1 overexpression enhanced p-CSF1R/CSF1R and p-STAT1/STAT1 expression, while knockdown CSF1 using anti-CSF1 siRNAs decreased p-CSF1R/CSF1R and p-STAT1/STAT1 expression. Furthermore, the inhibitor of CSF1R significantly decreased p-STAT1/STAT1 expression.

CONCLUSIONS

Sputum CSF1 may be involved in asthmatic airway eosinophil inflammation by interacting with CSF1R and further activating the STAT1 signaling. Interfering this potential pathway could serve as an anti-inflammatory therapy for asthma.

Eosinophil Inflammation and Hyperresponsiveness in the Airways as Phenotypes of COPD, and Usefulness of Inhaled Glucocorticosteroids

Background: The differential diagnosis in persistent airway limitation is sometimes not so clear in older adults. Airway eosinophilia and airway hyperresponsiveness may develop in some cases with chronic obstructive lung disease (COPD), independent of asthma. However, little is known about clinical significance of these phenotypes of COPD in detail. Aims and objectives: This clinical study was designed to examine prevalence of airway eosinophilia and airway hyperresponsiveness in COPD who have no symptom and no past history of asthma, and to examine involvement of these pathophysiological features of asthma in the management and therapy for COPD. Methods: Sputum examination via qualitative and quantitative procedures was performed in stable COPD (GOLD 1-3). When sputum eosinophils were qualitatively (≥+) or quantitatively assessed (≥3%), ciclesonide (inhaled glucocorticosteroids) was added on bronchodilators. In cases with FEV₁ ≥ 70% of predicted values, acetylcholine provocation test was examined for assessment of airway hyperresponsiveness. Therapeutic effect was evaluated using spirometry and COPD assessment test (CAT). Results: Sputum eosinophils were observed in 65 (50.4%) of 129 subjects using qualitative analysis; in contrast, lower grade (>0%) and higher grade (≥3%) were observed in 15 (20.3%) and 25 (33.8%) of 74 subjects using quantitative analysis. Airway hyperresponsiveness developed in 46.9% of these subjects with sputum eosinophils. Exacerbations occurred much more frequently in lower-grade airway eosinophilia without ciclesonide than in higher-grade airway eosinophilia with ciclesonide. Airway hyperresponsiveness significantly increased frequency of exacerbations in COPD with both lower and higher grade in airway eosinophilia. Addition of ciclesonide to indacaterol markedly improved lung function (FEV₁, IC), CAT score, and reliever use in these subjects with airway eosinophilia determined by qualitative analysis. However, ciclesonide was less effective in improving these values in subjects with airway hyperresponsiveness than in those without airway hyperresponsiveness. Conclusions: Airway eosinophilia and airway hyperresponsiveness are complicated with 25-50% of COPD that have no symptom and history for asthma. These phenotypes of COPD are closely related to symptom stability and reactivity to glucocorticosteroids. These phenotypes may play key roles for advancement of the management and therapy of this disease.