Macrolides attenuate mucus hypersecretion in rat airways through inactivation of NF-kappaB.

BACKGROUND AND OBJECTIVE: To examine the effect of a 14-membered ring macrolide on airway mucus hypersecretion in rats treated with LPS. METHODS: Mucus hypersecretion in rat airways was induced by intratracheal instillation of LPS. Rats treated with or without LPS were administered roxithromycin (1-10 mg/kg), josamycin (10 mg/kg) or amoxicillin (40 mg/kg), orally for 4 days. Expression of Muc5ac, nuclear factor (NF)-kappaB, and the mitogen-activated protein (MAP) kinases p38 and ERK1/2 in bronchial epithelium were detected by RT-PCR, immunohistochemistry or western blotting. Mucins, IL-1beta, IL-8 and tumour necrosis factor (TNF)-alpha in BAL fluid were assayed by enzyme-linked lectin assay and ELISA. RESULTS: LPS significantly induced the expression of Muc5ac mRNA and protein in bronchial epithelium, increased the release of mucins, IL-1beta, IL-8 and TNF-alpha, and increased neutrophil numbers in BAL. Moreover, LPS increased staining for NF-kappaB in the cytoplasm as well as nuclear translocation of NF-kappaB in airway epithelial cells. Upregulated expression of Muc5ac mRNA correlated positively with NF-kappaB activation and the levels of cytokines (P < 0.05). Roxithromycin (5 and 10 mg/kg) significantly attenuated bronchial Muc5ac expression and NF-kappaB nuclear translocation stimulated by LPS, and reduced neutrophil numbers, mucins and inflammatory cytokines in BAL (P < 0.05). However, LPS-stimulated expression of p38 and ERK1/2 in airway epithelium was not affected by roxithromycin. Josamycin and amoxicillin had no effects on Muc5ac expression, NF-kappaB activation or cytokine release. CONCLUSIONS: Roxithromycin inhibits the pulmonary inflammatory response and airway mucus hypersecretion induced by LPS. The inhibitory effect of roxithromycin on airway mucus hypersecretion may be mediated through reduction of NF-kappaB activation, neutrophil infiltration and release of inflammatory cytokines in the lung.

Increased expression of human calcium-activated chloride channel 1 gene is correlated with mucus overproduction in Chinese asthmatic airway.

Asthma is usually complicated with mucus overproduction in airway. Recently the increased expression of the human calcium-activated chloride channel 1 (CaCC1) was found to play an important role in mucus overproduction in the asthmatic airways. To investigate the relationship of Calcium-activated chloride channel 1 (CaCC1) and mucus overproduction in Chinese asthmatic airway, the expression of CaCC1, mucin 5AC (MUC5AC) and mucus in bronchial tissues were examined. Bronchial tissues were isolated from non-cancerous areas of lungs obtained following resection for lung neoplasm in West China Hospital from April to July in 2004. Six patients were diagnosed lung neoplasm with moderate asthma, and other ten were diagnosed lung neoplasm without asthma as the control subjects. The expression of CaCC1, MUC5AC and mucin in bronchial tissues was detected by reverse transcriptase-polymerase chain reaction (RT-PCR), in situ hybridized with digoxigenin (DIG)-labeled RNA probe, immunohistochemical and Alcian blue-periodic acid Schiff (AB-PAS) staining, respectively. In RT-PCR, two expression patterns of CaCC1 mRNA were found, which were located in the 450 bp and 510 bp. With in situ hybridization, a stronger expression of CaCC1 mRNA was further detected throughout the bronchial tissues from patients with asthma than control subjects (P<0.01); Samples from asthmatics were showed a stronger staining for MUC5AC than those in control subjects (P<0.05); AB-PAS staining revealed more mucins and goblet cells in asthmatic bronchial epithelium and submucosal gland comparing to that in control subjects (P<0.05). The increased expression of CaCC1 in asthmatic airways was well correlated with the expression of MUC5AC protein, the percentage of goblet cells and the area of submucosal gland (P<0.01, P<0.01, P<0.05). These results suggest that the up-regulated gene expression of CaCC1 exists, which is complicated with mucus hyper-secretion in Chinese asthmatic airway.

Increased expression of human calcium-activated chloride channel 1 is correlated with mucus overproduction in the airways of Chinese patients with chronic obstructive pulmonary disease.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is usually complicated with mucus overproduction in airway. Recently the increased expression of the human calcium-activated chloride channel 1 (CaCC(1)) was found to play an important role in mucus overproduction in the asthmatic airways. To investigate the relationship of CaCC(1) and mucus overproduction in the airway of Chinese patients with COPD, the expressions of CaCC(1), MUC5AC and mucus in bronchial tissues were examined. METHODS: Bronchial tissues were obtained from fiberoptic bronchoscopy and bronchial biopsy in West China Hospital from April to July in 2004. Twenty-five patients were diagnosed as the patients with COPD overproduction, and other 20 were the control subjects. The expressions of CaCC(1), MUC5AC and mucin in bronchial tissues were detected by reverse transcriptase-polymerase chain reaction (RT-PCR), in situ hybridization with digoxigenin (DIG)-labeled RNA probe, immunohistochemical and alcian blue-periodic acid Schiff (AB-PAS) staining, respectively. RESULTS: Compared with the control group, the stronger expressions of CaCC(1) were further detected throughout the bronchial tissues from patients with COPD (P < 0.01). Furthermore, the stronger expressions of the CaCC(1) mRNA were related to the severity of airflow obstruction. Samples from COPD showed a stronger staining for MUC5AC than those in control subjects (P < 0.01) and AB-PAS staining revealed more mucins in COPD patients' submucosal gland comparing with that in control subjects (P < 0.01). Expression levels of the CaCC(1) mRNA were respectively negatively correlated with the patients' forced expiratory volume in one second (FEV(1))/forced vital capacity (FVC) data, FEV(1)% predicted data, V(50)% predicted data, V(25)% predicted data (r = -0.43, r = -0.43, r = -0.35, r = -0.36, P < 0.01, P < 0.01, P < 0.05, P < 0.05). While the expression levels of the CaCC(1) mRNA were well correlated with the expression levels of the MUC5AC mRNA of airway epithelium and the PAS-AB stained area of submucosal glands (r = 0.39, r = 0.46, P < 0.05, P < 0.01). Expression levels of the MUC5AC mRNA were negatively correlated with the patients' FEV(1)/FVC data (P = 0.01), FEV(1)% pred data (P = 0.01), V(50)% predicted data, V(25)% predicted data (r = -0.53, r = -0.53, r = -0.48, r = -0.43, P < 0.01, P < 0.01, P < 0.01, P < 0.01). While the expression levels of the MUC5AC mRNA were well correlated with the positively PAS-AB stained area of submucosal gland (P < 0.05), and the correlation coefficients were 0.43. CONCLUSION: These results suggest that the stronger gene expression of CaCC(1) exists, complicated with mucus overproduction in the airway of Chinese patients with COPD.