Yukiko Tando

Differences in the released endothelial microparticle subtypes between human pulmonary microvascular endothelial cells and aortic endothelial cells in vitro.

ABSTRACT Circulating endothelial microparticles (EMPs) are membrane vesicles that are shed into the blood stream from activated or apoptotic endothelial cells. We previously reported that circulating EMP numbers significantly increased in stable chronic obstructive pulmonary disease (COPD) patients and during exacerbation compared with healthy control subjects. However, different types of circulating EMPs with distinct time profiles were detectable during exacerbations. We hypothesized that the released EMP subtypes correlated with differences in the inflammatory stimuli and the endothelial cell type. We compared the EMP subtypes from human aortic endothelial cells (Aortic ECs) and human lung microvascular endothelial cells (Pulmonary microvascular ECs) released in response to various stimuli, including proinflammatory cytokines (TNFα), oxidative stress (H2O2), and cigarette smoke extracts (CSE) in vitro. We defined circulating EMPs by the expression of endothelial antigens: CD144+ MPs (VE-cadherin EMPs), CD31+/CD41− MPs (PECAM EMPs), CD62E+ MPs (E-selectin EMPs), and CD146+ MPs (MCAM EMPs). E-selectin EMPs were released from both pulmonary microvascular and aortic ECs in response to TNFα but not to H2O2 or CSE stimulation. The amount of MCAM EMPs released from pulmonary microvascular ECs differed significantly between the cells stimulated with H2O2 and those stimulated with CSE. VE-cadherin EMPs were only released from aortic ECs, whereas PECAM EMPs were released exclusively from pulmonary microvascular ECs. The EMP subtypes released differ in vitro among TNFα, H2O2, and CSE stimulation as well as between pulmonary microvascular and aortic ECs. The differences in circulating EMP subtypes may reflect a condition or site of endothelial injury and may serve as markers for endothelial damage in COPD patients.

Histone deacetylase inhibitor restores surfactant protein-C expression in alveolar-epithelial type II cells and attenuates bleomycin-induced pulmonary fibrosis in vivo.

ABSTRACT Aim: Surfactant protein-C (SP-C) of alveolar epithelial type II cells (ATII) plays a key role in maintaining alveolar integrity and repair. Mutations or decreased expression of SFTPC, the gene encoding SP-C, causes ATII injury and aberrant repair of the lung tissue to develop pulmonary fibrosis. Histone deacetylases (HDACs) epigenetically remove acetyl groups from acetylated histones and regulate transcription. HDAC inhibitors attenuated epithelial-to-mesenchymal transition (EMT) and fibrotic disorders. The aim of this study is to investigate whether Trichostatin A (TSA), a pan-HDAC inhibitor, epigenetically exerts a protective effect on ATII against fibrotic changes via the restoration of SFTPC expression. Materials and Methods: We treated A549 cells with TGF-β1 to induce EMT, followed by TSA treatment. We evaluated SFTPC mRNA, histone acetylation levels in the SFTPC gene promoter region, and pro-SP-C protein. C57BL6/J mice were treated with intratracheal bleomycin instillation followed by TSA administration. Histological changes and Sftpc mRNA expression in isolated ATII were evaluated. Results: TGF-β1 treatment decreased SFTPC mRNA in A549 cells. TSA restored SFTPC mRNA, and increased histone H4 acetylation in the SFTPC promoter region in vitro. The administration of TSA partially attenuated BLM-induced pulmonary fibrosis and increased the Sftpc mRNA expression in isolated ATII from bleomycin-treated lungs in vivo. Conclusions: Decreased expression of SFTPC by TGF-β1 treatment was restored by TSA via hyperacetylation of histone H4 in the promoter region. TSA partially attenuated pulmonary fibrosis and increased Sftpc mRNA in ATII. Our findings suggest that the epigenetic restoration of SP-C would be a therapeutic target for pulmonary fibrosis.

Annual FEV1 changes and numbers of circulating endothelial microparticles in patients with COPD: a prospective study

Objective Growing evidence suggests that endothelial injury is involved in the pathophysiology of chronic obstructive pulmonary disease (COPD). Circulating endothelial microparticles (EMPs) increase in patients with COPD because of the presence of endothelial injury. We examined the relationship between EMP number and changes in forced expiratory volume in 1 s (FEV1) in patients with COPD. Design Prospective study. Setting One hospital in Japan. Participants A total 48 outpatients with stable COPD coming to the hospital from September 2010 to September 2011. Primary and secondary outcomes measured Blood samples were collected and vascular endothelial (VE)-cadherin EMPs (CD144+ EMPs), E-selectin EMPs (CD62E+ EMPs) and platelet endothelial cell adhesion molecule EMPs (CD31+/CD41− EMPs) were measured using fluorescence-activated cell sorting. Annual FEV1 changes were evaluated using FEV1 data acquired a year before and a year after sample collection. Results The number of E-selectin and VE-cadherin EMPs showed significant negative correlations with annual FEV1 changes (rs=−0.65, p<0.001, rs=−0.43, p=0.003, respectively). Leucocyte counts tended to be correlated with annual FEV1 changes, but this correlation was not significant (rs=−0.28, p=0.057). There were significant differences in annual FEV1 changes between with and without history of frequent exacerbation (p=0.006), and among Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages (p=0.009). Multiple linear regression analysis revealed E-selectin EMP to be the only significant parameter associated with annual FEV1 changes, independent of VE-cadherin EMP, GOLD stages, leucocyte counts, and history of frequent exacerbation. Receiver operating characteristic curves showed the optimum E-selectin EMP cut-off level for prediction of rapid FEV1 decline (>66 mL/year) to be 153.0/µL (areas under curve 0.78 (95% CI 0.60 to 0.89); sensitivity, 67%; specificity, 81%). Conclusions The high E-selectin EMP levels in stable patients with COPD are predictive of rapid FEV1 decline. Trial registration number UMIN000005168.

Increased Severity of 2009 Pandemic Influenza A Virus Subtype H1N1 Infection in Alveolar Type II Cells From Patients With Pulmonary Fibrosis

TO THE EDITOR—Weinheimer et al [1] reported that influenza A viruses preferentially infect alveolar epithelial type II (ATII) cells in lung tissue explants and suggested that the pathogenicity of influenza A viruses is associated with the ability of these viruses to replicate in ATII cells and induce the production of inflammatory cytokines. In contrast, an epidemiological study by Nguyen-Van-Tam et al [2] demonstrated that chronic pulmonary comorbidities such as pulmonary fibrosis were risk factors for poor outcomes for 2009 pandemic influenza A virus subtype H1N1 (A[H1N1]pdm09) infection. Pulmonary fibrosis is a collective and clinicopathological term for a disease characterized by shortness of breath during exercise, abnormal lung physiology, reduced gas transfer, and excessive scar formation in the lung interstitium. Two studies using genome-wide RNA interference screening identified host factors that are required for the replication of influenza virus [3, 4]. These studies suggest that not only viral strains but also host factors associated with existing pulmonary diseases should be studied to gain a better understanding of the mechanisms of influenza A virus pathogenesis. To our knowledge, there are no studies investigating whether influenza virus infection of ATII cells in diseased lungs is more severe than in normal lungs. On the basis of an epidemiological study [2], we hypothesized that the infection of ATII cells with A(H1N1) pdm09 is more severe for cells from pulmonary fibrotic lungs than for cells from nonfibrotic lungs. To address this question, we infected ATII cells isolated from fibrotic lungs and nonfibrotic lungs with A(H1N1)pdm09 and then compared viral titers in the culture supernatants. This study was approved by the ethics committees of the Tohoku University School of Medicine and the Japanese Red Cross Ishinomaki Hospital. All patients gave their informed consent. Nonfibrotic lung tissue specimens were obtained from 4 patients who underwent surgery because of lung cancer. The nonfibrotic tissue specimens were resected from portions distal to the cancerous lesions. A histopathological examination confirmed that these nonfibrotic lung tissues did not contain any lesions, including those associated with cancer, fibrosis, emphysema, or inflammatory changes (data not shown). Fibrotic lung tissue specimens were obtained from patients who underwent open lung biopsy or lung resection because of lung cancer. The clinical diagnoses based on pathological examinations of the fibrotic lesions included idiopathic pulmonary fibrosis (in 3 patients), cellular nonspecific interstitial pneumonia (in 1), and chronic hypersensitivity pneumonitis (in 1). We excluded patients in whom other respiratory disorders, such as asthma or chronic obstructive pulmonary disease, were diagnosed that might also be risk factors for poor outcomes for A(H1N1) pdm09 infection [5]. We also excluded patients who had been treated with chemotherapy before surgery.

The serine protease inhibitor camostat inhibits influenza virus replication and cytokine production in primary cultures of human tracheal epithelial cells

Abstract Background Serine proteases act through the proteolytic cleavage of the hemagglutinin (HA) of influenza viruses for the entry of influenza virus into cells, resulting in infection. However, the inhibitory effects of serine protease inhibitors on influenza virus infection of human airway epithelial cells, and on their production of inflammatory cytokines are unclear. Methods Primary cultures of human tracheal epithelial cells were treated with four types of serine protease inhibitors, including camostat, and infected with A/Sendai-H/108/2009/(H1N1) pdm09 or A/New York/55/2004(H3N2). Results Camostat reduced the amounts of influenza viruses in the supernatants and viral RNA in the cells. It reduced the cleavage of an influenza virus precursor protein, HA0, into the subunit HA1. Camostat also reduced the concentrations of the cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α in the supernatants. Gabexate and aprotinin reduced the viral titers and RNA levels in the cells, and aprotinin reduced the concentrations of TNF-α in the supernatants. The proteases transmembrane protease serine S1 member (TMPRSS) 2 and HAT (human trypsin-like protease: TMPRSS11D), which are known to cleave HA0 and to activate the virus, were detected at the cell membrane and in the cytoplasm. mRNA encoding TMPRSS2, TMPRSS4 and TMPRSS11D was detectable in the cells, and the expression levels were not affected by camostat. Conclusions These findings suggest that human airway epithelial cells express these serine proteases and that serine protease inhibitors, especially camostat, may reduce influenza viral replication and the resultant production of inflammatory cytokines possibly through inhibition of activities of these proteases.

Receptor for advanced glycation end products expressed on alveolar epithelial cells is the main target for hyperoxia-induced lung injury

BACKGROUND Receptor for advanced glycation end products (RAGE) is abundantly expressed on alveolar epithelial cells (AECs) and participates in innate immune responses such as apoptosis and inflammation. However, it is unclear whether RAGE-mediated apoptosis of AECs is associated with hyperoxia-induced lung injury. METHODS We used wild-type and RAGE-knockout C57BL6/J mice in this study. In addition, we developed bone marrow chimeric mouse models expressing RAGE on hematopoietic or non-hematopoietic cells, including lung parenchymal cells, and compared survival ratios and changes in the permeability of the alveolar-capillary barrier after hyperoxia exposure. Further, we prepared single cell suspensions of lung cells and evaluated the apoptosis of AECs or microvascular endothelial cells (MVECs) by using a combination of antibodies and JC-1 dye. We also examined whether RAGE inhibition decreased hyperoxia-induced apoptosis of human lung epithelial cells in vitro. RESULTS After hyperoxia exposure, mice expressing RAGE on lung cells showed lower survival rate and increased alveolar-capillary permeability than mice expressing RAGE on hematopoietic cells. RAGE-expressing AECs showed significantly higher apoptosis than RAGE-knockout AECs after in vivo hyperoxia exposure. The level of hyperoxia-induced apoptosis was not different in MVECs. However, RAGE-null lung epithelial cells showed lower apoptosis than RAGE-expressing cells in vitro. CONCLUSION These results indicated that RAGE on AECs mainly contributed to hyperoxia-induced lung injury and alveolar-capillary barrier disruption.

Expression of cytochrome P450 mRNAs in Type II alveolar cells from subjects with chronic obstructive pulmonary disease

Inhaled drugs are critical for the treatment of inflammatory airway diseases such as chronic obstructive pulmonary disease (COPD). To develop better therapeutics for pulmonary disease it is of potential importance to understand molecular mechanisms of local biotransformation in the lung. Alveolar epithelial type II (ATII) cells have a key role in homeostasis in the lung, but little is known about expression patterns of genes encoding cytochrome P450 (CYP) enzymes in ATII cells. In addition, alteration of CYP gene expression has not been fully defined in COPD. We previously established a method to purify ATII cells from the adult human lung using fluorescence‐activated cell sorting. By employing this technique we determined gene expression patterns of 14 CYP enzymes in ATII cells from nonsmokers (n = 4) and smokers (n = 4), both having normal pulmonary function. Although most CYP genes are highly expressed in primary hepatocytes, we found that CYP1B1 mRNA expression was 7.2‐fold higher in ATII compared to hepatocytes (P = .0275). Additionally we noted a 3.0‐fold upregulation of CYP2C19 and 50% reduction in CYP2J2 mRNA expressions in ATII cells isolated from patients with COPD (n = 3) compared to smokers without COPD (n = 4). These data, for the first time, detail a comprehensive set of genes encoding CYP enzymes in human ATII cells and highlights differentially expressed CYP mRNAs of patients with COPD. Such understanding may have important implications for the development of novel inhaled drugs.

The Role of Lysophosphatidic Acid on Airway Epithelial Cell Denudation in a Murine Heterotopic Tracheal Transplant Model.

Background Chronic rejection is the major leading cause of morbidity and mortality after lung transplantation. Obliterative bronchiolitis (OB), a fibroproliferative disorder of the small airways, is the main manifestation of chronic lung allograft rejection. However, there is currently no treatment for the disease. We hypothesized that lysophosphatidic acid (LPA) participates in the progression of OB. The aim of this study was to reveal the involvement of LPA on the lesion of OB. Methods Ki16198, an antagonist specifically for LPA1 and LPA3, was daily administered into the heterotopic tracheal transplant model mice at the day of transplantation. At days 10 and 28, the allografts were isolated and evaluated histologically. The messenger RNA levels of LPAR in microdissected mouse airway regions were assessed to reveal localization of lysophosphatidic acid receptors. The human airway epithelial cell was used to evaluate the mechanism of LPA-induced suppression of cell adhesion to the extracellular matrix (ECM). Results The administration of Ki16198 attenuated airway epithelial cell loss in the allograft at day 10. Messenger RNAs of LPA1 and LPA3 were detected in the airway epithelial cells of the mice. Lysophosphatidic acid inhibited the attachment of human airway epithelial cells to the ECM and induced cell detachment from the ECM, which was mediated by LPA1 and Rho-kinase pathway. However, Ki16198 did not prevent obliteration of allograft at day 28. Conclusions The LPA signaling is involved in the status of epithelial cells by distinct contribution in 2 different phases of the OB lesion. This finding suggests a role of LPA in the pathogenesis of OB.