Xuemei Ou

Decreased expression of human aquaporin-5 correlated with mucus overproduction in airways of chronic obstructive pulmonary disease

AbstractAim:To investigate the relationship between aquaporin-5 (AQP5) expression and mucus overproduction in the airways of Chinese patients with chronic obstructive pulmonary disease (COPD) and the correlation with pulmonary function change.Methods:Bronchial tissues were obtained from fiberoptic bronchoscopy and bronchial biopsy in West China Hospital from April to July 2004. Twenty-five patients were diagnosed as COPD patients, and another 20 were diagnosed as the control patients. The expressions of AQP5, mucin 5 AC (MUC5AC), and mucin in bronchial tissues were detected by semiquantitative RT-PCR, in situ hybridization, and immunohistochemical and alcian blue-periodic acid-Schiff (AB-PAS) staining, respectively.Results:Compared with the control group, an attenuated expression of AQP5 was detected throughout the bronchial tissues from patients with COPD (P<0.01), but no difference existed in the lung tissues (P>0.05). Simultaneously, increased staining of MUC5 AC and mucus in submucosal glands were noted (P<0.01, respectively). Smoking attenuated the expressions of AQP5 and increased the staining of MUC5AC and mucus in submucosal glands in the COPD groups (P<0.01), while there were no significant differences observed in the control group (P>0.05). The decreased expression of AQP5 mRNA was correlated with forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) (r=0.60, P<0.01), FEV1% predicted value (r= 0.60, P<0.01), maximal expiratory flow in 50% vital capacity (V50)% predicted value (r=0.55, P<0.01), and maximal expiratory flow in 25% vital capacity (V25) % predicted value (r=0.45, P<0.01). The decreased expression was negatively correlated with MUC5 AC mRNA of the epithelium airways (r=−0.45, P<0.01) and the AB-PAS-stained area of submucosal glands (r=−0.61, P<0.01). The upregulation of MUC5AC mRNA correlated with the positively AB-PAS-stained area of submucosal glands and correlated negatively with FEV1/FVC (r=−0.53; P<0.01), FEV1% predicted value (r=−0.53; P<0.01), V50% predicted value (r=−0.48; P<0.01), and V25% predicted value (r=−0.43; P<0.01).Conclusion:The attenuated gene expression of AQP5 existed in the airways of Chinese COPD patients, which was complicated by mucus hypersecretion. The decreased expression of AQP5 mRNA may be related to the severity of airflow obstruction.

VEGFR-2 antagonist SU5416 attenuates bleomycin-induced pulmonary fibrosis in mice

OBJECTIVE Abnormal angiogenesis is a central hallmark for the development and progression of idiopathic pulmonary fibrosis. It has been shown that vascular endothelial growth factor (VEGF) is one of the critical angiogenic factors in angiogenesis. The aim of the present study was to assess whether disruption of VEGF pathway would attenuate bleomycin-induced pulmonary fibrosis. METHODS Bleomycin-induced pulmonary fibrosis mice were treated intraperitoneally with VEGF receptor tyrosine kinase inhibitor SU5416 at different phases after bleomycin infusion. We measured angiogenesis and inflammatory response in both bleomycin-treated and control mice, and correlated these levels with pulmonary fibrosis. RESULTS The increased expressions of VEGF/VEGFR (Flk-1) were correlated to a larger number of microvessels and a higher score of pulmonary fibrosis. Early administration of SU5416 inhibited pulmonary collagen deposition, histopathologic fibroplasias and the activation of TGF-beta1/Smad3 signaling pathway in bleomycin-stimulated lung. These were also paralleled by a reduction of VEGF/VEGFR-2 (Flk-1) expression and microvessel numbers in lung. Furthermore, SU5416 inhibited inflammatory cell numbers and LDH activity in BALF and IL-13 expression in lung tissue at early inflammatory phase of bleomycin-induced pulmonary fibrosis. CONCLUSION These results suggest that the VEGFR-2 inhibitor, SU5416, attenuates histopathologic fibroplasias and collagen deposition by regulating angiogenesis and inflammation in the lung.

Rosiglitazone, a peroxisome proliferator-activated receptor-γ agonist, attenuates acrolein-induced airway mucus hypersecretion in rats

BACKGROUND Peroxisome proliferator-activated receptor-gamma (PPAR-gamma), a member of the ligand-activated nuclear receptor superfamily, has been shown to be implicated in anti-inflammatory and immunomodulatory responses, but its role in airway mucus hypersecretion remains not clear. OBJECTIVE To investigate the role of PPAR-gamma in airway mucus hypersecretion, we used an acrolein-exposed rat model treated with rosiglitazone, a peroxisome proliferator-activated receptor-gamma agonist. METHODS Rats were exposed to acrolein (3.0 ppm, 6h/day, 7 days/week) and orally administered with rosiglitazone (2, 4, 8 mg/kg) once daily for up to 2 weeks. The expressions of Muc5ac protein and mRNA, and infiltration of inflammatory cells and levels of inflammatory cytokines (interleukin (IL)-1beta, IL-8 and tumor necrosis factor (TNF)-alpha) in bronchoalveolar lavage fluid (BALF) were detected with real-time PCR, Western blot, cell counting and ELISA. In addition, the role of nuclear factor (NF)-kappaB pathway in this process was also explored. RESULTS Acrolein exposure significantly induced goblet cell hyperplasia in bronchial epithelium and Muc5ac mRNA and protein expressions in rat lungs, as well as the associated airway inflammation evidenced by the increased numbers of inflammatory cells and levels of inflammatory cytokines in BALF, which were attenuated with rosiglitazone treatment in a dose-dependent manner (P<0.05). Simultaneously, the increased expression of NF-kappaB and decreased expression of cytoplasmic IkappaB in acrolein-exposed lungs were reversed by rosiglitazone treatment. CONCLUSIONS These findings suggest that PPAR-gamma activation by its ligands can attenuate acrolein-induced airway mucus hypersecretion in rats, which may be involved in inhibition of NF-kappaB pathway.

Involvement of ERK, Bcl-2 family and caspase 3 in recombinant human activin A-induced apoptosis in A549

BACKGROUND Activins are members of the transforming growth factor-beta (TGF-beta) superfamily. Previous studies have shown that activin A may have a central role in regulating both apoptosis and proliferation. However, direct studies of recombination human activin A on human NSCLC A549 cells have not yet been reported. The purpose of this study was to investigate whether activin A could induce apoptosis in A549 cells and the possible mechanisms via which it worked. METHODS Cellular apoptosis induced by activin A was detected by TUNEL assay and the levels of protein expression were detected by western blot. RESULTS Recombination human activin A induced apoptosis in human NSCLC A549 cells in a concentrate-dependent manner. Activin A-induced A549 apoptosis was accompanied by the up-regulation of Bax, Bad and Bcl-Xs and down-regulation of Bcl-2. Moreover, activin A treatment increased the expression of its typeII receptors, activated ERK and caspase 3 in A549. These results clearly demonstrate that the induction of apoptosis by activin-A involves multiple cellular/molecular pathways and strongly suggest that pro- and anti-apoptotic Bcl-2 family proteins and caspase 3 participate in activin A-induced apoptotic process in A549 cells. On the other hand, activin A treatment had little effect on primary human small airway epithelial cells (SAECs). CONCLUSION Recombination human activin A induced apoptosis in A549 cells, at least partially, through ERK and mitochondrial pathway. The result that activin A did not affect the normal SAEC revealed activin A might be considered as a potential anticancer agent and worthy of further studies.

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.

Advanced Chronic Obstructive Pulmonary Disease: Innovative and Integrated Management Approaches

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide and results in an economic and social burden that is both substantial and increasing. By the year 2020, COPD will be the third leading cause of mortality and the fifth leading cause of disability worldwide.[1] In a population based study conducted at multiple international sites, approximately 10% of participants 40 years of age or older were found to have airflow obstruction of at least moderate severity according to spirometric criteria.[2] In China, the overall prevalence of COPD in individuals 40 years of age or older was 8.2%.[3] COPD is a slowly progressive respiratory disease, which, although preventable and treatable, is not curable. The final years for patients with advanced COPD are characterized by progressive functional decline, frequent exacerbations, poor quality of life, increasing dependency on informal caregivers and on the health care system.[4] According to the literature, 5‐year survival from diagnosis is estimated to be 78% in men and 72% in women with mild disease, but only 30% in men and 24% in women with advanced COPD.[5]

Association of five genetic variants with chronic obstructive pulmonary disease susceptibility and spirometric phenotypes in a Chinese Han population

Recent genome‐wide association studies have shown associations between variants at five loci (TNS1, GSTCD, HTR4, AGER and THSD4) and chronic obstructive pulmonary disease (COPD) or lung function. However, their association with COPD has not been proven in Chinese Han population, nor have COPD‐related phenotypes been studied. The objective of this study was to look for associations between five single nucleotide polymorphisms (SNP) in these novel candidate genes and COPD susceptibility or lung function in a Chinese Han population.

Diagnostic Accuracy of Ber-EP4 for Metastatic Adenocarcinoma in Serous Effusions: A Meta-Analysis

Numerous studies have investigated the utility of Ber-EP4 in differentiating metastatic adenocarcinoma (MAC) from malignant epithelial mesothelioma (MM) and/or reactive mesothelial cells (RM) in serous effusions. However, the results remain controversial. The aim of this study is to determine the overall accuracy of Ber-EP4 in serous effusions for MAC through a meta-analysis of published studies. Publications addressing the accuracy of Ber-EP4 in the diagnosis of MAC were selected from the Pubmed, Embase and Cochrane Library. Data from selected studies were pooled to yield summary sensitivity, specificity, positive and negative likelihood ratio (LR), diagnostic odds ratio (DOR), and receiver operating characteristic (SROC) curve. Statistical analysis was performed by Meta-Disc 1.4 and STATA 12.0 softwares. 29 studies, based on 2646 patients, met the inclusion criteria and the summary estimating for Ber-EP4 in the diagnosis of MAC were: sensitivity 0.8 (95% CI: 0.78–0.82), specificity 0.94 (95% CI: 0.93–0.96), positive likelihood ratio (PLR) 12.72 (95% CI: 8.66–18.7), negative likelihood ratio (NLR) 0.18 (95% CI: 0.12–0.26) and diagnostic odds ratio 95.05 (95% CI: 57.26–157.77). The SROC curve indicated that the maximum joint sensitivity and specificity (Q-value) was 0.91; the area under the curve was 0.96. Our findings suggest that BER-EP4 may be a useful diagnostic adjunctive tool for confirming MAC in serous effusions.

The potential interaction of MARCKS-related peptide and diltiazem on acrolin-induced airway mucus hypersecretion in rats☆

UNLABELLED Airway mucus hypersecretion is recognized as a pathophysiological feature of airway inflammation. Ca2+ entry and myristoylated alanine-rich C kinase substrate translocation are considered as important factors in such process. To investigate the potential interaction of myristoylated alanine-rich C kinase substrate (MARCKS)-related peptide and diltiazem on acrolein-induced airway mucus hypersecretion in rats, rat model of airway mucus hypersecretion was established by inhalation of acrolein on 12 consecutive days. MARCKS-related peptide, diltiazem, saline or the combination (MARCKS-related peptide+diltiazem) was intratracheally administered respectively. The rats were received pilocarpine to stimulate mucus release before sacrifices. The expression of Mucin5ac in bronchoalveolar lavage fluid (BALF) was measured by ELISA. Intracellular Muc5ac level was detected by immunohistochemical staining and western-blot. Muc5ac mRNA in lung was analyzed by RT-PCR. RESULTS Instillation of MARCKS-related peptide attenuated the release of Muc5ac in BALF induced by acrolein(p<0.05). Diltiazem alone had no effect on mucus hypersecretion induced by acrolein. However, the release of Muc5ac in BALF was further reduced when challenged with simultaneous instillation with MARCKS-related peptide and diltiazem, compared with MARCKS-related peptide alone (p<0.05). The intracellular level of Muc5ac in lung was increased when treated with MARCKS-related peptide alone or MARCKS-related peptide plus diltiazem (p<0.05). Nevertheless, diltiazem alone did not take effect as above. CONCLUSIONS In the model of airway mucus hypersecretion induced by acrolein, MARCKS-related peptide attenuated mucus secretion and the inhibitory effect was enhanced by diltiazem, which may be due to a further diminution of the intracellular free calcium concentration and retention of mucin within epithelial goblet cells.