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Mesenchymal stem cells (MSCs) have been shown to improve acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). However, the optimal source of MSCs for cell-based therapy remains unknown. To determine which kind of MSCs are more effective, we compared the effects of rat lung resident MSC (LRMSC), human chorion-derived MSC (HMSC-C) and human bone marrow derived MSC (HMSC-BM) in LPS-induced ALI in mice.LPS (Pseudomonas aeruginosa) was used to induce ALI model. All three kinds of MSCs were administered via tail vein 4 h after LPS instillation. The mice were sacrificed 48 h after LPS instillation. HE staining of lung section, wet-to-dry weight ratio of lung tissue, ratio of regulatory T cells (Tregs) and Th17 cells, and total protein concentration, leukocytes counting and cytokines in bronchoalveolar lavage fluid (BALF) were evaluated.The data showed that compared with LRMSC and HMSC-BM, HMSC-C more significantly attenuated lung injury, upregulated the Tregs/Th17 cells ratio, and inhibited release of inflammatory cytokines (IL-1β, IL-6 and TNF-α) and recruitment of neutrophils and macrophages into alveolus.Although all three kinds of LRMSC, HMSC-C and HMSC-BM are protective against LPS-induced lung injury, HMSC-C was more effective than LRMSC and HMSC-BM to treat LPS-induced lung injury.

Mucus hypersecretion is a prominent mechanism in airway inflammation. Muc5ac is a major component of mucus and can be activated by reactive oxygen species (ROS). Peroxiredoxin 6 (Prdx6) highly expresses in airway epithelium and protects the airway from oxidative stress. In this study, we investigated the roles of Prdx6 in lipopolysaccharide (LPS)-induced mucin production in mice. We found that the levels of H2O2 and the Muc5ac mRNA were significantly increased in Prdx6 (-/-) mice compared to those in C57BL/6J mice after LPS instillation, which were markedly inhibited by epithelial growth factor receptor (EGFR) inhibitor Elrotinib. In vitro studies showed that mRNA levels of Prdx6 were decreased while H2O2 and Muc5ac were increased in a dose-dependent manner after LPS exposure, with significant increase in Prdx6 knockdown bronchial epithelial cells compared with those in normal epithelial cells. LPS-induced Muc5ac release was significantly inhibited by EGFR inhibitor, p38 inhibitor and JNK inhibitor, but not ERK1/2 inhibitor, indicating that the H2O2-EGFR-MAPK pathway is likely involved in the responses. This study indicated that Prdx6 decreased LPS-induced Muc5ac increase and played important roles in mucin hypersecretion after LPS exposure.

In this study, we utilized AQP3-knockout mice as the in vivo model and AQP3-knockdown human bronchial epithelial cells (HBECs) as the in vitro model. Airway injury was experimentally induced by intra-tracheal injection of naphthalene. HE staining, transmission and scanning electron microscope were performed to evaluate self-healing capacity in vivo. Transwell and wound-healing assays were performed to evaluate epithelial cell migration in vitro. We found that both the airway epithelial cells of AQP3-knockout mice and AQP3-knockdown HBECs exhibited an obviously impaired self-healing capacity with defective epithelial cell migration through AQP3-facilitated glycerol transport. In addition, glycerol supplementation could largely correct defective injury healing and epithelial cell migration. For the first time, we found evidence for distinct defects in AQP3-deficient airway epithelial cell migration. Mechanistic analysis showed AQP3-facillitated glycerol transport plays a role in airway epithelial self-healing after injury.

Blocking PcrV, an essential component of the Type III secretion system (TTSS), has demonstrated efficacy against Pseudomonas aeruginosa infections. However, most of the results came from laboratory strains. Whether it is applicable to clinically isolated multi-drug resistant (MDR) strains is unknown. In this study we investigated the expression level of TTSS in clinically isolated MDR P. aeruginosa strains and the effects of anti-PcrV antibody on MDR isolate induced acute lung injury (ALI). The expression level of TTSS was quantified in 53 isolates including 25 MDR strains and 28 susceptible strains. We investigated the effect of anti-PcrV antibody through a murine model induced by instillation of a MDR strain into the left lung through trachea. Our results showed that the expression level of TTSS in MDR strains is comparable to susceptible strains. Anti-PcrV ensured the survival of challenged mice, reduced the bacteria numbers and attenuated lung inflammation and injury. This study proved that anti-PcrV may be a potentially effective strategy against MDR P. aeruginosa induced ALI.

Ovalbumin (OVA)-induced asthma in mouse lungs causes changes in the mRNA and protein levels of aquaporins (AQPs). AQP expression was examined in the presence of various anti-asthmatic agents, including dexamethasone, ambroxol, and terbutaline. The influence of these agents on OVA-induced airway inflammation was also evaluated. The mRNA expression levels of AQP1, 4, and 5 were significantly reduced and that of AQP3 was significantly increased 24h after the last OVA exposure. The protein levels of AQP1, 3, and 5 mirrored the mRNA expression profiles, but AQP4 did not exhibit any changes. Only the mRNA and protein expression levels of AQP1 and AQP5 were significantly increased by these three anti-asthmatic agents. Dexamethasone and ambroxol improved the eosinophil infiltration, mucus secretion, and pulmonary edema caused by OVA, but terbutaline only alleviated pulmonary edema. These results indicate that AQP1 and AQP5 are closely related to pulmonary edema but not to eosinophil infiltration or mucus secretion during asthma. Anti-asthmatic agents could alleviate pulmonary edema through upregulating the expression of AQP1 and AQP5 in mouse lungs that have OVA-induced asthma.

A new intravascular fluorosensor was developed and validated for inline P CO 2 monitoring. The P CO 2 sensor was based on the fluorescent indicator 1-hydroxypyrene-3,6,8-trisulfonate. The P CO 2 sensor was then immersed in various solutions in vitro and carotid artery bypass of rabbits in vivo for testing. Changes of P CO 2 in solutions and blood were created by bubbling CO2/N2 and hyperventilation/hypoventilation, respectively. The changes of fluorescent intensity over P CO 2 range of 14–150 mmHg was linear. The resolution of the whole sensor system was 1 mmHg, with a bias ± SD of −0.1 ± 2.9 mmHg and precision ± SD of 2.1 ± 1.9 mmHg. The sensor signal has been stable during measurement for at least 25 h and was insensitive to fluctuations of ions concentration and osmosis at pathophysiological limits. The performance of the sensor is in agreement with blood gas analyzer in a wide range of P CO 2 and it is qualified for continuous intravascular measurement of blood P CO 2 at various conditions.

Insufficiency of tissue repair by pulmonary fibroblasts may contribute to the decrease in elastic fibres in chronic obstructive pulmonary disease (COPD). In this study, the repair function of COPD fibroblasts was assessed by examining the response to transforming growth factor (TGF)-β1. Primary pulmonary fibroblasts were cultured from lung tissue of COPD patients and smoking control subjects. Cellular proliferation was measured with Alamar Blue reduction method. Levels of tropoelastin mRNA and soluble elastin was measured using real-time RT-PCR and Fastin elastin assay respectively. The percentage of increase in proliferation and elastin production after TGF-β1 (1 ng/ml) treatment was calculated for fibroblasts from each subject. COPD fibroblasts showed slower proliferation than control fibroblasts, and a reduced response to TGF-β1 stimulation. The promotive effect of TGF-β1 on elastin synthesis in control fibroblasts was significantly diminished in fibroblasts from COPD patients. Our findings indicate that COPD lung fibroblasts have a significantly decreased response to TGF-β1 in terms of proliferation and elastin production.

Background Aquaporin 5 (AQP5) is widely expressed in various organ and tissues. In light of the novel oncogenic properties of aquaporins (AQPs), here we investigated the effect of AQP5 knockdown by RNAi on transmembrane osmotic water permeability, cell migration potential and cell volume regulation ability. Methods AQP5 expression was inhibited by short hairpin RNA in SPC-A1 cells, a lung adenocarcinoma cell line. Cells loaded with a fluoroprobe (calcein-AM) were immersed in either isosmotic, hyperosmotic or hyposmotic solutions, and fluorescence intensity was recorded using confocal microscopy. These measurements were used to calculate osmotic water permeability coefficients (Pf) and to monitor regulated volume decrease (RVD). Tumor cell migration and invasion assays were performed in a modified Boyden chamber. Wound healing and colony forming ability were also tested. Results Although self-quenching was not found in SPC-A1 cells, we observed a linear relationship between fluorescence intensity and cell water volume, suggesting that this method is a sensitive and reproducible way to measure single-cell transmembrane water permeability. Cells in which the AQP5 gene was silenced showed a 49.4% decrease in osmotic water permeability, a 55.3% decrease in migration and a 28.4% decrease in invasion potential. In addition, RVD decreased remarkably with reduced osmotic water permeability. Conclusion Our results suggest that AQP5, which mediates water permeability and thus regulates cell shape and volume, is a potentially important determinant in cell migration.

The aim of the present study was to evaluate the effects of the CC chemokine receptor (CCR) 2b and CCR1 antagonist RS504393 as well as the roles of CCRs on lipopolysaccharide (LPS)-induced acute lung injury (ALI). In A549 cell line, treatment with RS504393 significantly inhibited the expression of CCR1, CCR2 and interleukin (IL)-8 after either LPS or tumor necrosis factor-alpha stimulation. An ALI model with intranasal LPS administration was used on C57BL/6J, CCR1, CCR2 and CCR3 knockout mice. Treatment with RS504393 had a noteworthy preventative effect on LPS-induced over-expression of IL-1beta, plasminogen activator inhibitor and CCR2. In CCR1 and CCR2-deficient animals, LPS-induced less increase of lung weight, bronchoalveolar lavage (BAL) leukocytes and IL-6 compared to the C57BL/6J and CCR3 knockout mice. This was most prominent in the CCR2 knockout mice where no LPS-induced lung edema and no increase of IL-6 in BAL fluid occurred. Our results indicate that CCR2, and to some extent CCR1, play pivotal roles in the development of ALI.

The accurate measurement of arterial blood oxygen partial pressure often plays an important role in the clinical assessment of patients with respiratory conditions such as an acute exacerbation of chronic obstructive pulmonary disease and acute lung injury/adult respiratory distress syndrome. An oxygen-sensitive fluorescence indicator with high biocompatibility was synthesized and then fabricated to the end of an optical fiber. The properties and accuracy of this oxygen sensor were investigated in vitro using physiologic solutions under varying conditions or human blood, and in vivo by obtaining measurements after inserting this optical sensor into the collateral circulation system of rabbits. The sensitivity of the oxygen sensor was relatively stable during altered conditions of pH, P C O 2 , osmolality, and protein concentration in solutions and during alterations of oxygen and nitrogen content in human blood. There was a linear correlation between the reciprocal value of the fluorescence intensity and P a O 2 in both in vivo and in vitro experiments (animal arterial circulation and human blood). Our results suggest that this oxygen-sensitive fluorescence indicator, which has a high biocompatibility, may have the potential for use in real-time monitoring of blood oxygen partial pressure in various clinical settings.

Diffuse panbronchiolitis (DPB) is a pulmonary disease of unknown etiology that predominantly affects East Asians, particularly Japanese with a prevalence of 0.00028. Research has shown that HLA-B54 and HLA-A11 are positively associated with this disease. HLA-A, -B, and -DR loci were analyzed using an oligonucleotide microarray in both Chinese patients with DPB and normal control subjects. The most marked difference between the patients and the controls was the decreased frequency of HLA-A2 ( p = 0.001, OR = 0.12), which showed a negative association with the disease; however, there was no significant contribution of HLA-B loci. Interestingly, the frequency of HLA-A11 was increased ( p = 0.007, OR = 3.9), in accordance with previous reports on Japanese and Koreans. In addition, the frequency of HLA-DRB5*010/020 slightly increased ( p = 0.049). The HLA-associated genes for DPB are located between the HLA-A and HLA-B loci. Differences in HLA-associated genes may partially explain differences in the incidence of DPB among different populations.

The aquaporins (AQPs) are a family of homologous water channels expressed in many epithelial and endothelial cells, however no reliable and non-toxic inhibitors of AQPs have been reported yet. Our researchers have analyzed the changes of AQP5 expression induced by vector-based short hairpin RNA (shRNA) in the human airway submucosal gland cell line (SPC-A1) and observed its regulation on the expression of MUC5AC gene. Localizations of AQP5 and MUC5AC in SPC-A1cells were detected by Immunofluorescence. AQP5 mRNA was significantly reduced by 75.1% one day after transfection with specific shRNA, named shAQP5. However, the significant suppression of AQP5 protein did not appear until day 5 after transfection. MUC5AC mRNA was remarkably increased by 119.9% On day 3 after shAQP5 transfection, while comparable MUC5AC protein changes were not found in SPC-A1 cells with flow cytometry analysis. These results indicate that vector-based shRNA could be used as a potential tool to inhibit the expression of AQP5. This is the first investigation providing evidence demonstrating the regulation of the mucin gene by AQP5 gene silencing.

The role of the ENaC sodium channel and aquaporin-1 (AQP1) water channel on pleural fluid dynamics in mice was investigated. 0.25 ml of hypertonic or isosmolar fluid was infused into the pleural space in anesthetized wildtype and AQP1 null mice. Pleural fluid was sampled at specified times to quantify the osmolality and volume. The sodium channel activator terbutaline increased isosmolar fluid clearance by 90% while the sodium channel inhibitor amiloride decreased it by 15%, but had no effect on osmotically driven water transport. AQP1 deletion significantly decreased osmotic water transport in pleural space by twofold, but it had no effect on isosmolar fluid clearance. Pretreatment with dexamethasone increased pleural osmotic fluid entry by 25%, while intravenous injection of HgCl2 decreased osmotic pleural water movement by 43%. These results provided evidence for a role of a sodium channel in pleural fluid absorption; AQP1 plays a major role in osmotic liquid transport but it does not affect isosmolar fluid clearance.