Huanying Wan

Role of HIF-1α in the regulation ACE and ACE2 expression in hypoxic human pulmonary artery smooth muscle cells

Angiotensin-converting enzyme (ACE) enhances the proliferation and migration of pulmonary artery smooth muscle cells (PASMCs), which contribute to the pathogenesis of hypoxic pulmonary hypertension (HPH). Previous reports have demonstrated that hypoxia upregulates ACE expression, but the underlying mechanism is unknown. Here, we found that ACE is persistently upregulated in PASMCs on the transcriptional level during hypoxia. Hypoxia-inducible factor 1alpha (HIF-1alpha), a key transcription factor activated during hypoxia, was able to upregulate ACE protein expression under normoxia, whereas knockdown of HIF-1alpha expression in PASMCs inhibited hypoxia-induced ACE upregulation. Furthermore, HIF-1alpha can bind and transactivate the ACE promoter directly. Therefore, we report that ACE is a novel target of HIF-1alpha. Recently, a homolog of ACE, ACE2, was reported to counterbalance the function of ACE. In contrast to ACE, we found that ACE2 mRNA and protein levels increased during the early stages of hypoxia and decreased to near-baseline levels at the later stages after HIF-1alpha accumulation. Thus HIF-1alpha inhibited ACE2 expression, and the accumulated ANG II catalyzed by ACE is a key mediator in the downregulation of ACE2 by HIF-1alpha. Moreover, a reduction of ACE2 expression in PASMCs by RNA interference was accompanied by significantly enhanced proliferation and migration during hypoxia. We conclude that ACE is directly regulated by HIF-1alpha, whereas ACE2 is regulated in a bidirectional way during hypoxia and may play a protective role during the development of HPH. In sum, these findings contribute to the understanding of the pathogenesis of HPH.

Early production of IL-17 protects against acute pulmonary Pseudomonas aeruginosa infection in mice

Interleukin-17 (IL-17) is involved in protection against extracellular bacteria. However, IL-17 is likely to be deleterious to a host with chronic pulmonary Pseudomonas aeruginosa infection. The role of IL-17 during acute pulmonary P. aeruginosa infection remains unknown. Here, we evaluated the role that IL-17 plays in acute pulmonary P. aeruginosa infection and the source of the interleukin. The production of IL-17 increased rapidly after acute pulmonary P. aeruginosa infection in mice. We subsequently examined the role of IL-17 in acute infection and found 100 times more bacteria in the bronchoalveolar lavage fluid of mice treated with an IL-17-neutralizing antibody compared with the IgG(2a) -treated mice after 16 h of infection. The main infiltrating cells in the anti-IL-17-treated mice were lymphocytes rather than neutrophils. Consistently, more tissue damage and pathological changes in the lung were observed in the anti-IL-17-treated mice. We also found that Th17 cells are one of the sources of IL-17. We conclude that the early production of IL-17 plays a protective role during acute pulmonary P. aeruginosa infection in mice and that Th17 cells are one of the sources of IL-17 during acute pulmonary P. aeruginosa infection. Altogether, IL-17 and Th17 cells contribute to the pathogenesis of acute pulmonary P. aeruginosa infection in vivo.

Up-Regulation of Two Actin-Associated Proteins Prompts Pulmonary Artery Smooth Muscle Cell Migration under Hypoxia

Hypoxia stimulates the migration of pulmonary artery smooth muscle cells (PASMCs), which contributes to the pathogenesis of pulmonary vessel structural remodeling in hypoxic pulmonary hypertension (HPH). In the present study, we found, using a proteomics-based method, that gelsolin-like actin-capping protein (CapG) and transgelin were preferentially expressed in human (h)PAMSCs under hypoxia compared with normoxia. These two actin-associated proteins, modulate a variety of physiologic processes, including motility of cells, by interacting differently with the actin cytoskeleton. Our study showed that these two genes were up-regulated at both mRNA and protein levels under hypoxia in hPASMCs. As a key transcriptional regulation factor under hypoxia, hypoxia-inducible factor 1alpha (HIF-1alpha) up-regulated CapG protein expression under normoxia, and knockdown of HIF-1alpha expression in hPASMCs also inhibited hypoxia induced CapG up-regulation. However, HIF-1alpha could not regulate transgelin expression. Reduction of CapG or transgelin expression in hPASMCs by RNA interference was accompanied by significantly impaired migration ability in vitro, especially under hypoxia. Our study demonstrates that CapG and transgelin were preferentially expressed in hPAMSCs under hypoxia compared with normoxia. Hypoxia stimulates expression of these two actin-associated proteins via HIF-1alpha-dependent and -independent pathways, respectively. The up-regulation of these two proteins may contribute to the increased motility of hPASMCs under hypoxia. These findings may contribute to the understanding of the pathogenesis of HPH.

Systemic corticosteroid for COPD exacerbations, whether the higher dose is better? A meta-analysis of randomized controlled trials.

Systemic corticosteroids (SCS) have been shown to improve the outcome of acute exacerbation of chronic obstructive pulmonary disease (AECOPD). However, the optimal dose remains controversial.

Efficacy of sublingual immunotherapy for allergic asthma: retrospective meta-analysis of randomized, double-blind and placebo-controlled trials

Allergen‐specific immunotherapy (SIT) is the only available curative choice with a disease‐modifying effect against respiratory allergies. The efficacy of SIT via the sublingual route was demonstrated by a number of clinical trials. This meta‐analysis was performed to investigate the clinical efficacy and safety of sublingual‐specific immunotherapy (SLIT) for allergic asthma.

Use of Cardioselective β-Blockers in Patients with Chronic Obstructive Pulmonary Disease: A Meta-Analysis of Randomized, Placebo-Controlled, Blinded Trials

Objective: To assess the effect of cardioselective b-blockers on pulmonary function in patients with chronic obstructive pulmonary disease (COPD). Methods: The Embase and MEDLINE™ databases and the Cochrane Controlled Trials Register were searched comprehensively to identify all relevant clinical trials in humans published between January 1966 and May 2011. Randomized, blinded, placebo-controlled trials that studied the effects of cardioselective ß-blockers on the forced expiratory volume in 1 s (FEV1) and the responsiveness of the FEV1 to ß-agonist administration in patients with COPD were included in the analysis. Results: Five studies were identified: four of these assessed both cardioselective and nonselective ß-blockers; one assessed only cardioselective ß-blockers. The FEV1 was shown to decrease by 0.14 l with nonselective ß-blockers and by 0.03 l with cardioselective ß-blockers. The responsive -ness of the FEV1 to ß-agonist administration decreased significantly by 13.42% after nonselective ß-blockers, but did not change significantly after cardioselective -blocker administration. Conclusion: This meta-analysis suggests that the use of β-blockers, especially cardioselective β-blockers, should not be contraindicated in patients with COPD.

The responses of γδ T‐cells against acute Pseudomonas aeruginosa pulmonary infection in mice via interleukin‐17

Interleukin (IL)-17-producing T-lymphocytes play a crucial role in inflammation, yet the potential roles of the cells in acute bacterial pulmonary infection remain unclear. Here, we investigated the role of IL-17-producing γδ T-cells in a mouse model of acute Pseudomonas aeruginosa pulmonary infection. Results showed that augmentation of IL-17, IL-22 and IL-23 was associated with the development of acute bacterial pulmonary infection. However, IL-17 was markedly reduced following the blockade of γδ T-cell activity in vivo. The levels of the chemokines, including granulocyte colony-stimulating factor (G-CSF), keratinocyte chemoattractant (KC), macrophage inflammatory protein-1α (MIP-1) and macrophage inflammatory protein (MIP-2), were also noticeably decreased in the anti-γδ T Cell Receptor(TCR) mice after 8 h infection. Following the depletion of γδ T-cells, the bacterial load was consistently increased. Anti-TCRγδ-treated mice had changes similar to those in the the anti-IL-17-treated mice. The mRNA and protein levels of IL-22 and IL-23, and the mRNA level of RORγt were all markedly decreased in the anti-TCRγδ mice. Overall, our results demonstrated that at the early stage of acute P. aeruginosa pulmonary infection, γδ T-cells are the major source of IL-17 and play a pivotal role in the host immune response and defense against bacteria.

Association of genetic polymorphisms with chronic obstructive pulmonary disease in the Chinese Han population: a case–control study

BackgroundChronic obstructive pulmonary disease (COPD) is influenced by both environmental and genetic factors. Few gene studies of the Chinese population have focused on COPD. We investigated candidate genes associated with susceptibility to COPD in the Chinese Han population.MethodsA total of 331 COPD patients and 213 control subjects were recruited for this study. Nighty-seven single-nucleotide polymorphisms (SNPs) of 46 genes were selected for genotyping. Genotypes were determined using multiplex polymerase chain reaction (PCR).ResultsSignificant differences between patients and healthy controls were observed in the allele frequencies of seven SNPs: rs1205 C, rs2353397 C, rs20541 T, rs2070600 G, rs10947233 G, rs1800629 G, and rs2241712 A. After Bonferroni correction, rs2353397 C was most strongly associated with susceptibility to COPD. Haplotype analysis showed that the frequencies of the GC, GT haplotypes of rs2241718 (TGF-β1 gene), and rs6957 (CDC97 gene) were significantly higher in the control group than in the COPD case group (p=1.88×10-9); the frequencies of the TT haplotype of rs1205 and rs2808630 (CRP gene) were significantly higher in the control group (p=0.0377).ConclusionOur study suggests some genetic variants associated with the susceptibility of COPD in the Chinese Han population.

Lack of association between the TGF-β(1) gene and development of COPD in Asians: a case-control study and meta-analysis.

Abnormalities in the transforming growth factor-β1 (TGF-β1) gene are thought to be linked to chronic obstructive pulmonary disease (COPD). We investigated the association between the single nuclear polymorphisms (SNPs) of TGF-β1 and the risk of COPD in a case–control study and meta-analysis. We genotyped 160 cases and 177 control subjects in a local hospital using the Mass-ArrayTM Technology Platform and then tested the association of four SNPs in TGF-β1 (rs6957, rs1800469, rs2241712, and rs2241718) with COPD. Plasma TGF-β1 level measurement was performed later. A database covering all papers published up to October 30, 2010, was then reviewed. Statistical analysis was performed using Revman 5.0 and STATA 11.0 software. No association was found between TGF-β1 gene SNPs and an increased risk of COPD in Asians. By meta-analysis, the link of two polymorphisms, rs1800469 and rs1982073, was investigated in seven and eight studies, respectively, involving 1508 COPD patients and 2608 control subjects. The results showed that there was no significant association between an increased risk of COPD in carriers of the T allele (TT+TC) versus the CC genotype in rs1800469 and rs1982073. In ethnic subgroup analysis, the risk of COPD associated with the rs1800469 T allele was not significantly elevated among Asians. TGF-β1 gene polymorphisms are not associated with an increased risk of COPD in the Asian population.

Whole-exome sequencing to identify novel somatic mutations in squamous cell lung cancers.

Squamous cell lung cancer is a major histotype of non-small cell lung cancer (NSCLC) that is distinct from lung adenocarcinoma. We used whole-exome sequencing to identify novel non-synonymous somatic mutations in squamous cell lung cancer. We identified 101 single-nucleotide variants (SNVs) including 77 non-synonymous SNVs (67 missense and 10 nonsense mutations) and 11 INDELs causing frameshifts. We also found four SNVs located within splicing sites. We verified 62 of the SNVs (51 missense, 10 nonsense and 1 splicing-site mutation) and 10 of the INDELs as somatic mutations in lung cancer tissue. Sixteen of the mutated genes were also mutated in at least one patient with a different type of lung cancer in the Catalogue of Somatic Mutation in Cancer (COSMIC) database. Four genes (LPHN2, TP53, MYH2 and TGM2) were mutated in approximately 10% of the samples in the COSMIC database. We identified two missense mutations in C10orf137 and MS4A3 that also occurred in other solid-tumor tissues in the COSMIC database. We found another somatic mutation in EP300 that was mutated in 4.2% of the 2,020 solid-tumor samples in the COSMIC database. Taken together, our results implicate TP53, EP300, LPHN2, C10orf137, MYH2, TGM2 and MS4A3 as potential driver genes of squamous cell lung cancer.