hCLCA1 DNA vaccine suppresses cell hyperplasia and mucin expression of goblet cells in vitro.

BACKGROUND: Excessive airway mucus secretion is a remarkable trait of asthma. Mucus overproduction mainly resulted from an increase in goblet cell numbers, which causes considerable damage to health. However, effective therapeutic treatments are still lacking for mucus hypersecretion. Human calcium-activated chloride channel 1 (hCLCA1) has been identified to be predominantly responsible for mucus hypersecretion. OBJECTIVES: In this study, we investigated the effects of an hCLCA1 DNA vaccine on the control of mucus production and goblet cell proliferation using an in vitro model goblet cell line (NCI-H292). METHODS: The effect of the hCLCA1 DNA vaccine on cell viability and proliferative activity of NCI-H292/hCLCA1 was analyzed by electron microscopy, MTT assay, and flow cytometry. Expression of mucins and MUC5AC, a major member of the mucin gene family in airway goblet cells, was assessed under hCLCA1 DNA vaccine challenges by periodic acid-Schiff staining, quantitative real-time PCR and Western blot, respectively, and the expression profile of granulocyte-macrophage colony-stimulating factor (GM-CSF), a critical cytokine in airway inflammation, was also examined by real-time PCR and immunocytochemistry. RESULTS: Results showed that hCLCA1 overexpression caused high cell proliferation and mucin expression, whereas the hCLCA1 DNA vaccine could effectively reverse these abnormal effects. In addition, GM-CSF expression was highly induced by hCLCA1 overexpression and efficiently suppressed by hCLCA1 DNA vaccine. CONCLUSIONS: These results illustrate that the hCLCA1 DNA vaccine effectively inhibits cell hyperplasia and mucin gene expression of goblet cells, suggesting that the hCLCA1 DNA vaccine has potential value in the treatment of human asthma.

Safety and immunogenicity of a DNA vaccine encoding human calcium-activated chloride channel 1 (hCLCA1) in asthmatic mice.

BACKGROUND: Calcium-activated chloride channels (CLCAs) have been found to be preferentially expressed on the secretory epithelium. They may play a pivotal role in mucous overproduction by bronchial goblet cells in asthma. It has been reported that the inhibition of CLCAs with niflumic acid could relieve the symptoms of asthma. However, niflumic acid has serious adverse effects. DNA vaccination is considered to be a promising strategy to treat allergic diseases such as asthma and dust mite allergy. METHODS: We constructed a vaccine encoding human CLCA1 (hCLCA1) and evaluated its effects on promoting antibodies against hCLCA1 and the related preventive function in a mouse model of asthma. RESULTS: Our results reveal that the induced hCLCA1 antibodies can be detected in the first 2 weeks after immunization with hCLCA1 plasmids (hCLCA1-p) by intramuscular injection and augmented gradually in the following several weeks. The autoantibodies against hCLCA1 induced by the DNA vaccine bound to three segments of the mouse CLCA3 (mCLCA3) protein, including the amino terminal (PepN), the carboxyl terminal (PepC) and the middle of the protein (PepM). In our study, mice immunized with hCLCA1-p developed fewer pathological changes compared with other control groups, including a remarkable reduction in the air pressure-time index of the trachea, the number of eosinophils and mast cells in the bronchoalveolar lavage fluid and the mRNA level of MUC5AC in goblet cells. CONCLUSION: Taken together, our results suggest that a DNA vaccine encoding the CLCA protein may have potential as a useful pharmacotherapy for asthma in the future.

Therapeutic effects of bone marrow-derived mesenchymal stem cells engraftment on bleomycin-induced lung injury in rats.

Previous studies have demonstrated that bone marrow-derived mesenchymal stem cell (MSC) engraftment attenuated lung injury in a model induced by bleomycin in mice. However, the mechanisms are not completely understood. The primary objective of the present study was to determine whether MSC engraftment can also protect lungs against bleomycin-induced injury in rats and to observe any beneficial effects of cytokines. Twelve hours after bleomycin (5 mg/kg) or phosphate-buffered saline was perfused into the trachea, 5x10(6) DAPI-labeled MSCs or DMEM-F12 were injected into the tail vein of rats. Two weeks later, MSCs labeled with DAPI were detected by pan-cytokeratin staining. The level of laminin and hyaluronan in bronchoalveolar lavage fluid was measured by radioimmunoassay. Collagen content in lung tissue was calculated by the hydroxyproline assay. TGF-beta1, PDGF-A, B, and IGF-I were measured by real-time PCR. It was observed that some MSCs positive for pan-cytokeratin staining, an indicator of alveolar epithelial cells, were present in injured lung tissue. Bleomycin injection increased the content of hydroxyproline in lung tissue, as well as laminin and hyaluronan in bronchoalveolar lavage fluid, markers for lung injury and fibrosis. However, these effects were attenuated by MSC treatment. Furthermore, the increased mRNA levels of TGF-beta1, PDGF-A, PDGF-B, and IGF-I following bleomycin injection were also significantly decreased by MSC treatment. These observations provided evidence that MSCs are still present in the lung 2 weeks after the initial MSC treatment in rats, as well as documented the beneficial effects of MSC engraftment against bleomycin-induced lung injury associated with changes in TGF-beta1, PDGF-A, PDGF-B, and IGF-I. These results may provide an experimental base for clinical therapy of pulmonary fibrosis in the future.

Biological treatment of ammonia gas at high loading.

The exhaust gas from compost processing plants contains a large amount of ammonia. To treat ammonia gas at high loads, bench-scale experiments were carried out. First, nitrifying bacteria were enriched from soil and immobilized on porous ceramics. The ceramics were packed in an acrylic cylinder (diameter, 100 mm; packed height, 190 mm) and ammonia gas was introduced to the top of the cylinder. The concentration and flow rate of ammonia gas were gradually increased and finally 85 ppm was introduced at a space velocity of 800 h(-1) (empty bed residence time (EBRT), 4.5 sec). The ammonia load was 1.0 kg N/m3 day(-1). The exhaust contained 1.5-2 ppm of ammonia. Then the packed ceramics were transferred to another acrylic cylinder (diameter, 50 mm; packed height, 800 mm). A high concentration of ammonia gas (1,000 ppm) was introduced at a space velocity of 96 h(-1) (ammonia loading, 1.44 kg N/m3 day(-1); EBRT, 37.5 sec). The exhaust contained 2 ppm of ammonia (removal rate, 99.8%). The packed bed was washed with water intermittently or continuously, and the wastewater from the cylinder contained a large amount of ammonium and nitrate ions of at a 1:1 ratio. Stoichiometric analysis showed that half of the introduced ammonia was oxidized to nitrate, and the rest was converted to ammonium ion. Thus, ammonia gas was effectively treated at a high load by biofiltration with nitrifying bacteria.

[A study of the effects of L-arginine in pathogenesis of hypoxic pulmonary hypertension].

AIM: To investigate the role of nitric oxide (NO), nitric oxide synthase (NOS) and endothelin-1 (ET-1) in the pathogenesis of hypoxic pulmonary hypertension and inhibiting effects of L-Arginine. METHODS: 30 rats were divided into 3 groups, normal control group (group NC); Hypoxic group (group HP): exposed to 10% O2 8 h/day, 3 weeks; Hypoxic + L-arginine (group LT): fed L-arginine 200 mg/kg before hypoxia. After exposed to hypoxia 21 days, hemodynamics were measured. Lung speciments were examined by light and electronic microscopes and morphometric analysis. NO, ET-1 levels in lung tissue were measured, the cNOS quantitative in the pulmonary endothelium were examined. RESULTS: In HP group, the mean pulmonary arterial pressure (m PAP), pulmonary vascular resistance (PVR) the percentage of completely muscular coattype medial muscle layer of pulmonary artery in intra-acine and ET-1 level of HP group increased (P < 0.01), but NO and cNOS level decreased (P < 0.01). Examined by electron micrograph, endothelium cells appeared swollen, broken and pealed of, basal lamina parted. The changes above in LT group reversed partly. But the changes above were still several than that of group NC (P < 0.05). CONCLUSION: The structure remodel of pulmonary arteries and endothelium lesion in hypoxia cause m PAP, PVP arising, that are correlated with the levels of ET-1 increasing and NO, cNOS decreasing. For L-arginine can partly supply NO, it may partly reverse the changes of HPH.

Effects of dietary supplementation on the function of alveolar macrophages of silicosis rats, on the blastogenic response of lymphocytes and on the peroxidase activity in blood of silicosis patients.

We studied the effects of a nutrient supplemented diet on the function of alveolar macrophages of silicosis rats and on the blastogenic response of lymphocytes, glutathione peroxidase (GSH-PX) activity, and lipid peroxidase (LPO) activity in the blood of silicosis patients. The results showed that a nutrient supplemented diet increased the phagocytosis rate (p < 0.01) and index (p < 0.05) of alveolar macrophages of silicosis rats. A nutrient supplemented diet also enhanced significantly the GSH-PX activity (p < 0.001) and the blastogenic response of lymphocytes (p < 0.01), and decreased substantially the LPO content (p < 0.05) in the blood of silicosis patients. We conclude that a nutrient supplemented diet may play an important role in antilipid peroxidation, decreased free radical reaction, stabilizing cell membrane, delaying lung fibrosis, and enhancing immune functions of the body.