Defect of Adaptation to Hypoxia in Patients With COPD Due to Reduction of Histone Deacetylase 7

BackgroundHypoxia inducible factor (HIF)-1 plays an important role in cellular adaptation to hypoxia by activating oxygen-regulated genes such as vascular endothelial growth factor (VEGF) and erythropoietin. Sputum VEGF levels are reported to be decreased in COPD, despite hypoxia. Here we show that patients with COPD fail to induce HIF-1α and VEGF under hypoxic condition because of a reduction in histone deacetylase (HDAC) 7.MethodsPeripheral blood mononuclear cells (PBMCs) were obtained from patients with moderate to severe COPD (n = 21), smokers without COPD (n = 12), and nonsmokers (n = 15). PBMCs were exposed to hypoxia (1% oxygen, 5% CO2, and 94% N2) for 24 h, and HIF-1α and HDAC7 protein expression in nuclear extracts were determined by sodium dodecyl sulfate poly acrylamide gel electrophoresis (SDS-PAGE)/Western blotting.ResultsHIF-1α was significantly induced by hypoxia in each group when compared with the normoxic condition (12-fold induction in nonsmokers, 24-fold induction in smokers without COPD, fourfold induction in COPD), but induction of HIF-1α under hypoxia was significantly lower in patients with COPD than in nonsmokers and smokers without COPD (P < .05 and P < .01, respectively). VEGF messenger RNA detected by quantitative real-time polymerase chain reaction was correlated with HIF-1α protein in nuclei (r = 0.79, P < .05), and HDAC7 protein expression was correlated with HIF-1α protein in nuclei (r = 0.46, P < .05). HDAC7 knockdown inhibited hypoxia-induced HIF-1α activity in U937 cells, and HIF-1α nuclear translocation and HIF-1α binding to the VEGF promoter in A549 cells.ConclusionsHDAC7 reduction in COPD causes a defect of HIF-1α induction response to hypoxia with impaired VEGF gene expression. This poor cellular adaptation might play a role in the pathogenesis of COPD

Up-regulation of serum periostin and squamous cell carcinoma antigen levels in infants with acute bronchitis due to respiratory syncytial virus

Background: Periostin and squamous cell carcinoma antigen (SCCA) are involved in the pathogenesis of asthma. Acute bronchitis due to respiratory syncytial virus (RSV) infection during infancy exhibits an asthma-like pathogenesis, suggesting that it may be associated with the subsequent development of asthma. However, the mechanism by which RSV infection leads to development of asthma has not yet been fully elucidated. Methods: Infants younger than 36 months were enrolled and classified into three groups. Group I included patients hospitalized with RSV-induced bronchitis. These patients were further stratified into two sub-groups according to whether the criteria for the modified Asthma Predictive Index (mAPI) had been met: Group I consisted of mAPI (+) and mAPI (−) patients; Group II included patients with food allergy as a positive control group; and Group III included children with no allergy as a negative control group. Serum periostin and SCCA levels were measured in the groups. This study was registered as a clinical trial (UMIN000012339). Results: We enrolled 14 subjects in Group I mAPI (+), 22 in Group I mAPI (−), 18 in Group II, and 18 in Group III. In Group I, the serum periostin and SCCA levels were significantly higher during the acute phase compared with the recovery phase. However, no significant differences were found between Group I mAPI (+) and mAPI (−). Conclusions: The serum periostin and SCCA levels increased during acute RSV bronchitis. Both periostin and SCCA may play a role in the pathogenesis of acute bronchitis due to RSV. Keywords: Infants, Periostin, Respiratory syncytial virus, Squamous cell carcinoma antigen, T-helper 2 cell cytokine