ABSTRACT: Background and objective: The aim of this study was to investigate the changes in expression of aquaporins (AQP) during differentiation of human bronchial epithelial cells and the role of lipopolysaccharide (LPS) in AQP expression. Methods: The levels of AQP3, AQP4 and AQP5 transcripts in human primary cultured bronchial epithelial cells were evaluated by real-time polymerase chain reaction at different time points before and after treatment with LPS. Western blotting was performed to assess the effects of LPS on AQP3, AQP4 and AQP5 expressions in normal human bronchial epithelial cells. Using pharmacological tools, the pathways involved in the regulation of LPS-induced changes in AQP5 were further explored. Results: The levels of AQP3, AQP4 and AQP5 transcripts were increased during differentiation of human bronchial epithelial cells. Expression of AQP5, but not AQP3 or AQP4, was downregulated by LPS. LPS-induced downregulation of AQP5 was inhibited by p38 and c-Jun N-terminal kinase (JNK) inhibitors. Conclusions: This study demonstrated that LPS decreases AQP5, but not AQP3 or AQP4, expression in human primary bronchial epithelial cells. The downregulation of AQP5 expression is mediated through a p38/JNK signalling pathway.
Respirology 07/2012; 17(7):1144-9. · 2.42 Impact Factor
ABSTRACT: ObjectiveLung cancer has emerged as a leading cause of cancer death in the world. Current therapies are ineffective, thus new approaches
are needed to improve the therapeutic ratio. RNA interference (RNAi) has shown promise in gene silencing in vitro, the potential of which in developing new methods for the therapy of non-small-cell lung cancer (NSCLC) needs to be further
tested in vivo. In this study, chemically synthesized double-stranded RNA (dsRNA) targeting epidermal growth factor receptor (EGFR) was
transfected into NSCLC cell line SPC-A1 cells and established the tumor burdened athymic nude mice model to investigate whether
dsRNA could induce gene silencing in NSCLC cells in vivo.
MethodsSPC-A1 was transfected with EGFR sequence-specific dsRNA formulated with Lipofectamine 2000. SPC-A1 cells (1 × 107/mL) in 200 μL were injected s.c. into the left flank area of the mice to establish the tumor burdened athymic nude mice model.
Calculate the tumor growth inhibition rate by measuring the diameter and the weight of the tumor. Immunohistochemistry and
Western blot were used to monitor the reduction in the production of the EGFR protein. Realtime RT-PCR was used to detect
the silencing of the EGFR mRNA level.
ResultsIt displayed that EGFR sequence specific dsRNA (dsRNA-EGFR) significantly inhibited the tumor growth in vivo. The tumor growth
inhibition rate was 75.03%. The dsRNA-EGFR sequence specifically silenced EGFR with 53.6% of down-regulation of EGFR protein
production and 32.3% of silencing of EGFR mRNA level.
ConclusionDsRNA-EGFR showed a blockbuster effect in downregulation of EGFR mRNA level and protein production, and inhibition of tumor
growth in vivo.
The Chinese-German Journal of Clinical Oncology 04/2012; 8(8):463-466.
ABSTRACT: Proper H(2)O to mucin ratio of airway mucus is important for mucociliary clearance. Recent studies suggest that decreased aquaporin 5 (AQP5) is correlated with increased staining of MUC5AC in submucosal glands of COPD patients. Lipopolysaccharide (LPS) is one of the major insults in airway mucin secretion in COPD. In this study, changes in both AQP5 and MUC5AC expression levels in SPC-A1, a human airway submucosal gland cell line, were quantified after exposure of the cells to LPS. AQP5 transcription and protein expression were decreased while MUC5AC expression was increased by LPS exposure in SPC-A1 cells. Further studies revealed that AQP5 expression was down-regulated via the p38/JNK signaling pathway, while MUC5AC was up-regulated through the EGFR-p38/JNK pathway. Therefore, p38 and JNK may become promising targets to preserve AQP5 expression and prevent MUC5AC over-expression to restore proper H(2)O to mucin ratio of the airway mucus, which may be beneficial to the clinical management of COPD patients.
Respiratory Physiology & Neurobiology 03/2010; 171(3):212-7. · 2.24 Impact Factor
ABSTRACT: Continuous monitoring of PaO(2) in seriously ill patients is an important aspect of clinical management, especially for patients with acute lung injury (ALI) or acute respiratory distress syndrome. We have developed a fibreoptic sensor to detect PaO(2)in vivo based on fluorescence quenching technology. In this study we evaluated the sensitivity of this sensor in monitoring PaO(2) in a rabbit model with ALI.
The oxygen sensor is a membrane made of Ru(dpp)(3)(PF6)(2), poly-2-methacryloyloxyethyl phosphorylcholine and butylmethacylate copolymer p-(MPC-co-BMA) located at the tip of the optical fibre. The sensor was inserted into the carotid artery of the animals and monitored PaO(2) continuously. Oleic acid was intravenously injected to induce lung injury. Simultaneous comparisons were made between PaO(2) measured by blood gas analysis and PaO(2) measured by the fibreoptic sensor, both before and after lung injury.
The fluorescence intensity decreased gradually following ALI, reflecting increasing hypoxia. Correlation coefficients between measurements by the oxygen sensor and by the blood gas analysis were 0.995 +/- 0.003, 0.994 +/- 0.002 and 0.993 +/- 0.005 (P < 0.05) for control animals, animals with ALI and animals with electrolyte disturbance, respectively. The bias and precision for normal animals was -1.5 +/- 10.8 mm Hg, for animals with ALI was -1.2 +/- 11.2 mm Hg and for animals with electrolyte disturbance was -1.4 +/- 9.2 mm Hg.
The oxygen sensor showed high accuracy and stability for continuous monitoring of PaO(2) in normal animals, in animals with ALI and in animals with electrolyte disturbance, suggesting that it may be clinically useful in the continuous measurement of oxygen partial pressure.
Respirology 11/2009; 15(1):99-106. · 2.42 Impact Factor
ABSTRACT: Matrix metalloproteinases (MMPs) have been found to be involved in the pathogenesis of inflammatory airway diseases. However, the role of MMPs in lipopolysaccharide (LPS)-induced mucin overproduction remains unclear. We explored the role of MMP-9 in LPS-induced MUC5AC production and the effect of doxycycline on MUC5AC production. The study showed that LPS induced transcription and protein expression of both MMP-9 and MUC5AC in NCI-H292 cells and in primary human epithelial cells, and the increased MUC5AC level were associated with increased MMP-9 transcripts, protein and activity. However, the increase of MUC5AC transcripts and protein were diminished after cells had been treated with doxycycline, MMP-9 siRNA or EGFR inhibitor. Doxycycline inhibited MMP-9 transcription, protein production and activity, while LPS-induced increase of MMP-9 transcription was inhibited by EGFR inhibitor, p38 MAPK and JNK inhibitor. The LPS-induced phosphorylation of p38 MAPK and JNK were inhibited by EGFR inhibitor. These results suggested that LPS-induced MUC5AC production may be partially mediated by MMP-9 activation and EGFR-p38 MAPK/JNK signaling pathway. Doxycycline may play a therapeutic role in LPS-induced mucus hypersecretion.
Archives of Biochemistry and Biophysics 05/2009; 486(2):111-8. · 2.93 Impact Factor