Vitamin A-regulated ciliated cells promote airway epithelium repair in an asthma mouse model.

BACKGROUND: Asthma is a chronic inflammatory airway disease that causes damage to and exfoliation of the airway epithelium. The continuous damage to the airway epithelium in asthma cannot be repaired quickly and generates irreversible damage, repeated attacks, and aggravation. Vitamin A (VA) has multifarious biological functions that include maintaining membrane stability and integrity of the structure and function of epithelial cells. Our research explored the role of VA in repairing the airway epithelium and provided a novel treatment strategy for asthma. METHODS: A mouse asthma model was established by house dust mite (HDM) and treated with VA by gavage. Human bronchial epithelial (16HBE) cells were treated with HDM and all-trans retinoic acid (ATRA) in vitro. We analyzed the mRNA and protein expression of characteristic markers, such as acetyl-α-tubulin (Ac-TUB) and FOXJ1 in ciliated cells and MUC5AC in secretory cells, mucus secretion, airway inflammation, the morphology of cilia, and the integrity of the airway epithelium. RESULTS: Findings showed destruction of airway epithelial integrity, damaged cilia, high mucus secretion, increased MUC5AC expression, and decreased Ac-TUB and FOXJ1 expression in asthmatic mice. The VA intervention reversed the effect on Ac-TUB and FOXJ1 and promoted ciliated cells to repair the damage and maintain airway epithelial integrity. In 16HBE cells, we could confirm that ATRA promoted the expression of Ac-TUB and FOXJ1. CONCLUSION: These results demonstrated that VA-regulated ciliated cells to repair the damaged airway epithelium caused by asthma and maintain airway epithelial integrity. VA intervention is a potential adjunct to conventional treatment for asthma.

Loss of E-cadherin is causal to pathologic changes in chronic lung disease.

Epithelial cells line the lung mucosal surface and are the first line of defense against toxic exposures to environmental insults, and their integrity is critical to lung health. An early finding in the lung epithelium of patients with chronic obstructive pulmonary disease (COPD) is the loss of a key component of the adherens junction protein called E-cadherin. The cause of this decrease is not known and could be due to luminal insults or structural changes in the small airways. Irrespective, it is unknown whether the loss of E-cadherin is a marker or a driver of disease. Here we report that loss of E-cadherin is causal to the development of chronic lung disease. Using cell-type-specific promoters, we find that knockout of E-cadherin in alveolar epithelial type II but not type 1 cells in adult mouse models results in airspace enlargement. Furthermore, the knockout of E-cadherin in airway ciliated cells, but not club cells, increase airway hyperreactivity. We demonstrate that strategies to upregulate E-cadherin rescue monolayer integrity and serve as a potential therapeutic target.

PM2.5 affects establishment of immune tolerance in newborn mice by reducing PD-L1 expression.

This study was conducted to determine whether exposure to particulate matter 2.5 (PM2.5) affects the immune tolerance of neonatal mice via the regulation of PD-L1 expression. One-week-old BALB/c mice were exposed to PM2.5 for 8 days. From day 8 to day 18, the mice were treated with 5 µg house dust mite (HDM) (i. n.) every two days. Adenovirus-carried PD-L1 overexpression vectors were infected into mice via nasal inhalation 6 days after exposure to PM2.5. Airway hyperresponsiveness (AHR) was examined in mice 19 days after exposure to PM2.5, and the related parameters of airway inflammation were studied on day 22. Co-exposure to PM2.5 and HDM reduced PD-L1 expression but greatly increased infiltration of inflammatory cells, which was reversed by PD-L1 overexpression. Co-exposure to PM2.5 and HDM also elevated serum IL-4, IL-5 and IL-13 levels and reduced TGF-ß level. Exposure to PM2.5 alone slightly increased the numbers of dendritic cells (DCs) but reduced the numbers of antigen-presenting cells expressing PD-L1 and Treg cells. Therefore, early exposure to PM2.5 reduced PD-L1 expression in the lungs of neonatal mice, which interfered with immune tolerance establishment and subsequently resulted in allergic airway inflammation.

Enhanced pause correlates with airway neutrophils and airway-epithelial injury in asthmatic mice treated with dexamethasone.

OBJECTIVE: To investigate the correlations among airway inflammation, airway epithelial injury and airway hyperresponsiveness (AHR) in asthmatic mice treated with dexamethasone. METHODS: Female BALB/c mice were sensitized with intraperitoneal and hypodermic injections of ovalbumin (OVA) and aluminum on days 0, 7 and 14, challenged with OVA starting on day 21 for 10 days, and treated with dexamethasone via intraperitoneal injection starting on day 28 for 3 days. Female C57BL/6 mice were treated intranasally with house dust mite (HDM) on days 1 and 14, challenged intranasally with HDM on days 21, 23, 25, 27 and 29, and treated with sivelestat (a selective neutrophil elastase inhibitor) via intraperitoneal injection after each challenge. Following the final challenge, enhanced pause (Penh) and differential cell counts in the broncho-alveolar lavage fluid were measured and the correlations were analyzed. RESULTS: Compared with OVA-challenged BALB/c mice, the counterpart mice treated with dexamethasone showed reduced Penh and shedding of airway epithelial cells. In addition, we found that Penh 50 (an indicator of AHR) had positive correlations with airway neutrophils and shedding of airway epithelial cells, but no correlation with eosinophils, lymphocytes or macrophages. Moreover, shedding of airway epithelial cells had positive correlations with airway neutrophils, but no correlation with eosinophils, lymphocytes or macrophages. Further, sivelestat decreased Penh 50 and shed airway-epithelial cells in HDM-challenged C57BL/6 mice. CONCLUSIONS: Collectively, our findings suggest that airway neutrophils and excessive shedding of airway epithelial cells, but not eosinophils, lymphocytes or macrophages, may be involved in AHR in asthmatic mice treated with dexamethasone.

[The effect of CTLA4-Ig gene modified dendritic cell on Th1/Th2 balance in vitro].

AIM: To investigate the impact on Th1/Th2 subset balance from cytotoxic T lymphocyte-associated antigen immunoglobulin (CTLA4 Ig) gene-modified dendritic cells (CTLA4 Ig-DCs) in vitro. METHODS: The modified DCs (CTIA4 Ig-DCs) were prepared by transferring the mouse bone marrow-derived DCs with the constructed adenovirus CTIA4 Ig vectorî The CTLA4 Ig expression and certain cell surface molecules on the CTIA4Ig-DCs were detected by FCM, the potential to stimulate allogeneic T cell proliferation of the modified DCs by mixed lymphocyte reaction (MLR) and the secretion of IFN-γ and IL-4 in antigen presentation by ELISA. RESULTS: CTLA4 Ig gene was successfully transfected into DCs with stable expression of CTLA4 Ig, and its transfection efficiency was about 80%. Compared with the controls, CTLA4 Ig-DCs showed lower surface molecule CD86, inhibited allogeneic lymphocyte proliferation in MLR, decreased secretion of IFN-γ and IL-4 and increased ratio of IFN-γ/IL-4 in antigen presentation. CONCLUSION: CTLA4 Ig-DCs were successfully obtained and effectively expressed CTLA4 Ig, which could reduce the expression of CD86 on DCs surface. CTLA4 Ig-DCs inhibited allogeneic T cell proliferation and affected the ratio of Th1/Th2 in vitro.