Chlamydophila pneumoniae enhances secretion of VEGF, TGF-beta and TIMP-1 from human bronchial epithelial cells under Th2 dominant microenvironment.

PURPOSE: Chlamydophila pneumoniae infection in the airways is thought to be associated with the pathogenesis of asthma, especially in non-atopic severe asthma with irreversible airway obstruction that may be related to airway remodeling. Here, we investigated whether C. pneumoniae infection enhances the secretion of critical chemical mediators for airway remodeling, such as VEGF, TGF-beta, and TIMP-1, in human bronchial epithelial cells (BECs) in a Th2-dominant microenvironment. METHODS: Human bronchial epithelial cells (BEAS-2B cells) were infected with C. pneumoniae strain TW183 and cultured in both a Th1-dominant microenvironment with INF-gamma and a Th2-dominant microenvironment with IL-4 or IL-13 added to the culture medium. The VEGF, TGF-beta, and TIMP-1 levels in the culture supernatants were measured using enzyme-linked immunosorbent assays (ELISA). The activation of NF-kappaB in each experimental condition was determined using an electrophoretic mobility shift assay. RESULTS: Chlamydophila pneumoniae-infected BECs showed enhanced secretion of VEGF, TGF-beta, and TIMP-1 compared with non-infected BECs. The levels of cytokines secreted from BECs were increased more when IL-13 was added to the culture medium. C. pneumoniae-infected BECs also showed increased NF-kappaB activation. CONCLUSIONS: These results suggest that C. pneumoniae plays a role in the pathogenesis of airway remodeling in asthma, revealing a Th2-dominant immune response. Further studies are required to clarify the precise mechanism of C. pneumoniae infection in airway remodeling.

The tyrosine phosphatase, SHP-1, is involved in bronchial mucin production during oxidative stress.

Mucus hypersecretion is a clinically important manifestation of chronic inflammatory airway diseases, such as asthma and Chronic obstructive pulmonary disease (COPD). Mucin production in airway epithelia is increased under conditions of oxidative stress. Src homology 2 domain-containing protein tyrosine phosphatase (SHP)-1 suppression is related to the development of airway inflammation and increased ROS levels. In this study, we investigated the role of SHP-1 in mucin secretion triggered by oxidative stress. Human lung mucoepidermoid H292 carcinoma cells were transfected with specific siRNA to eliminate SHP-1 gene expression. Cultured cells were treated with hydrogen peroxide (H(2)O(2)), and Mucin 5AC(MUC5AC) gene expression and mucin production were determined. Activation of p38 mitogen activated protein kinase (MAPK) in association with MUC5AC production was evaluated. N-acetylcysteine (NAC) was employed to determine whether antioxidants could block MUC5AC production. To establish the precise role of p38, mucin expression was observed after pre-treatment of SHP-1-depleted H292 cells with the p38 chemical blocker. We investigated the in vivo effects of oxidative stress on airway mucus production in SHP-1-deficient heterozygous (mev/+) mice. MUC5AC expression was enhanced in SHP-1 knockdown H292 cells exposed to H(2)O(2), compared to that in control cells. The ratio between phosphorylated and total p38 was significantly increased in SHP-1-deficient cells under oxidative stress. Pre-treatment with NAC suppressed both MUC5AC production and p38 activation. Blockage of p38 MAPK led to suppression of MUC5AC mRNA expression. Notably, mucin production was enhanced in the airway epithelia of mev/+ mice exposed to oxidative stress. Our results clearly indicate that SHP-1 plays an important role in airway mucin production through regulating oxidative stress.

Chlamydophila pneumoniae triggers release of CCL20 and vascular endothelial growth factor from human bronchial epithelial cells through enhanced intracellular oxidative stress and MAPK activation.

BACKGROUND: Chlamydophila pneumoniae may contribute to the pathogenesis of asthmatic airway inflammation through chemical mediators secreted by C. pneumoniae-infected bronchial epithelial cells (BECs). Recently, CCL20 and vascular endothelial growth factor (VEGF) were reported to be released from BECs and to play a role in the pathogenesis of asthma. OBJECTIVE AND METHODS: To determine if C. pneumoniae infection of BECs induces the secretion of CCL20 and VEGF, we measured that by ELISA in human BECs infected with C. pneumoniae. Transcripts of CCL20 and VEGF were assayed by semi-quantitative RT-PCR. To investigate the underlying mechanism, the activation of MAPK and intracellular reactive oxygen species (ROS) in these C. pneumoniae-infected BECs was measured, as well as the effects of inhibitors of MAPK and ROS on CCL20 and VEGF expression. RESULTS: Compared with non-infected BECs, C. pneumoniae-infected BECs showed enhanced secretion of CCL20 and VEGF. C. pneumoniae-infected BECs also showed enhanced intracellular ROS and an increased ratio of phosphorylated to non-phosphorylated p38. Inhibition of p38 suppressed CCL20 and VEGF secretion, as did a NADPH oxidase blocker and an antioxidant, in C. pneumoniae-infected BECs. CONCLUSION: C. pneumoniae infection of BECs may play a role in the pathogenesis of asthma through the enhanced production of CCL20 and VEGF. The association between increased cytokine production and increased intracellular ROS suggests that antioxidants may benefit asthmatics in selected situations.

Increased expression of glucocorticoid receptor beta messenger RNA in patients with ankylosing spondylitis.

BACKGROUND: Glucocorticoids have been known to be less effective for treating ankylosing spondylitis (AS) patients than for treating rheumatoid arthritis (RA) patients. To elucidate the mechanisms underlying this phenomenon, we evaluated whether the glucocorticoid receptor (GR) beta expression of the peripheral blood mononuclear cells (PBMCs) in patients with AS is increased compared with patients with RA. METHODS: PBMCs were isolated from the subjects of 3 study groups: the healthy controls (n=25), the RA patients (n=25), and the AS patients (n=25). All the subjects had never taken corticosteroids and the patients with RA or AS were newly diagnosed. The expression of GR beta messenger RNA (mRNA) was determined by reverse transcription of the total RNA, and this was followed by semi-quantitative polymerase chain reaction analysis (RT-PCR). RESULTS: The level of GR alpha mRNA expression was not different among three groups. GR beta mRNA expression of the AS patients (2.02 [range: 0.99-7.21], median [25th-75th percentiles]) was enhanced compared with that of the controls (0.78 [range: 0.43-1.62]) and the RA patients (0.98 [range: 0.79-1.18]). The level of GR beta mRNA expression was not related to the inflammatory markers or the disease activity score 28 for the RA patients, and it was not related to the Bath ankylosing spondylitis disease activity index for the AS patients. CONCLUSION: The expression of GR beta mRNA, which is a dominant negative regulator for the glucocorticoid response, was increased in AS patients. The results suggest that the increased expression of GR beta mRNA may be related to the ineffectiveness of glucocorticoids for the treatment of AS.