Richness of sputum microbiome in acute exacerbations of eosinophilic chronic obstructive pulmonary disease.

BACKGROUND: The eosinophilic chronic obstructive pulmonary disease (COPD) is known to be more sensitive to corticosteroid. The sputum microbiome has been shown to affect COPD prognosis, but its role in acute exacerbations of eosinophilic COPD is unclear. This study aimed to investigate the dynamic changes of the airway microbiome in patients with acute exacerbations of eosinophilic COPD. METHODS: Fifty-seven patients with acute exacerbations of COPD from the First Affiliated Hospital of Guangxi Medical University between June 2017 and June 2018 were divided into two groups. Patients with eosinophils ≥300 cells/µL in the peripheral venous blood were assigned to the eosinophilic group (Eos) and the rest to the non-eosinophilic group (Noneos). All patients received similar treatment including inhaled budesonide according to the guidelines. The induced sputum microbiome was analyzed on the 1st and 7th day of treatment using the 16S ribosomal RNA (rRNA) method. The levels of interleukin (IL)-6 and IL-8 were measured in the plasma and the sensitivity to corticosteroids was determined in isolated peripheral blood mononuclear cells. Quantitative data were compared between the two groups using the independent samples t test or Mann-Whitney U test. Categorical data were evaluated using Chi-squared test or Fisher's exact test. RESULTS: Twenty-six patients were classified into Eos group and 31 patients were classified into Noneos group. Prior to treatment, the alpha diversity (Shannon index) (2.65 ±â€Š0.63 vs. 2.56 ±â€Š0.54, t = 0.328, P = 0.747) and the structure of the sputum microbiome were similar in the Eos group and the Noneos group. After 7 days of treatment, alpha diversity increased in both groups, while the microbiome richness (Ace index) was significantly lower in the Eos group (561.87 ±â€Š109.13 vs. 767.88 ±â€Š148.48, t = -3.535, P = 0.002). At the same time, IL-6 (12.09 ±â€Š2.85 pg/mL vs. 15.54 ±â€Š2.45 pg/mL, t = -4.913, P < 0.001) and IL-8 (63.64 ±â€Š21.69 pg/mL vs. 78.97 ±â€Š17.13 pg/mL, t = -2.981, P = 0.004) decreased more significantly in the Eos group, and the percentages of inhibition of IL-8 at dexamethasone concentrations 10 to 10 mol/L were significantly higher in the Eos group than those in the Noneos group (all P < 0.05). CONCLUSIONS: The induced sputum microbiome richness decreased more significantly following treatment in the Eos patients compared to the Noneos patients. The lower plasma inflammatory factor levels and the higher percentage of inhibition of IL-8 might be due to higher corticosteroid sensitivity in Eos patients.

Erythromycin reverses cigarette smoke extract-induced corticosteroid insensitivity by inhibition of the JNK/c-Jun pathway.

Corticosteroid insensitivity is a feature of airway inflammation in chronic obstructive pulmonary disease (COPD). Erythromycin exhibits anti-inflammatory activity in COPD, but the concrete mechanism is still unclear. This study aimed to investigate the effects of erythromycin on corticosteroid sensitivity in peripheral blood mononuclear cells (PBMCs) and U937 cells (a human monocytic cell line). PBMCs were collected from non-smokers, healthy smoker volunteers, and COPD subjects. U937 cells were incubated with or without erythromycin and stimulated with TNF-α in the presence or absence of cigarette smoke extract (CSE). The dexamethasone (Dex) concentration required to achieve 50% inhibition of TNF-α-induced interleukin (IL)-8 production was determined and the mitogen-activated protein kinase (MAPK)/Activator protein-1 (AP-1) pathway was also evaluated. Erythromycin improved corticosteroid sensitivity in PBMCs obtained from COPD patients and CSE-treated U937 cells. This improvement in corticosteroid sensitivity was associated with reduced c-Jun expression, which resulted from the inhibition of P38 Mitogen-activated protein kinase (P38MAPK), extracellular signal-regulated protein kinase (ERK)1/2, and c-Jun N-terminal kinase (JNK) phosphorylation. Erythromycin had no effects on the phosphorylated and total protein expression levels of P38MAPK and ERK; however, it induced inhibition of the phosphorylated and total protein expression levels of JNK. This study provides evidence that erythromycin restores corticosteroid sensitivity in PBMCs and U937 cells. JNK inhibition by erythromycin restores corticosteroid sensitivity via the inhibition of c-Jun expression. Thus, JNK/c-Jun is a potential novel therapeutic target for COPD.

Expression of GR-α and HDAC2 in steroid-Sensitive and steroid-Insensitive interstitial lung disease.

BACKGROUND: Corticosteroid is one of the main treatments for interstitial lung disease (ILD). Cryptogenic-organizing pneumonia (COP) is sensitive to corticosteroid therapy, whereas idiopathic pulmonary fibrosis (IPF) is not. Glucocorticoid receptor-α (GR-α) and histone deacetylase 2 (HDAC2) play critical roles in the sensitivity to corticosteroid therapy; however, it is unclear whether HDAC2 and/or GR-α are expressed in the lung tissues of patients with COP and/or IPF. Possible aberrant expressions of HDAC2 and GR-α in IPF and COP were investigated in the current study. METHODS: Lung tissue samples were obtained from patients with COP (n = 9), IPF (n = 8), pulmonary abscesses (n = 7), or pulmonary inflammatory pseudotumors (n = 6) before corticosteroid treatment, as well as from control subjects (n = 10). The expression of GR-α, HDAC2, PI3K-δ, and NF-κBp65 in the samples was assessed by immunohistochemistry. RESULTS: GR-α expression was the same in lung tissues from COP patients and control subjects, but was significantly lower in lung tissue from IPF. In addition, HDAC2 was significantly higher in lung tissues of COP patients compared to both IPF and control subjects. Furthermore, the transcription factor NF-κBp65 was significantly lower in lung tissues from both COP and control compared to IPF subjects, whereas there was no difference in NF-κBp65 when comparing tissues from COP patients to controls. HDAC2 and GR-α were negatively correlated with NF-κBp65 in COP lung tissue. CONCLUSION: HDAC2 and GR-α expression in lung tissues are potential biomarkers for predicting corticosteroid sensitivity when initially treating COP and IPF, as well as other forms of ILD.