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[Display omitted] • Robo2 can bind to NELL1/2 in acidic conditions but not physiological conditions. • The occluded NELL1/2-binding site is exposed by conformational change of Robo2. • Alternative splicing isoforms of Robo2 have distinct NELL1/2-binding affinities. • FRET-based indicators reveal that Robo2 changes conformation depending on acidic pH. Since neural epidermal growth factor-like-like (NELL) 2 was identified as a novel ligand for the roundabout (Robo) 3 receptor, research on NELL–Robo signaling has become increasingly important. We have previously reported that Robo2 can bind to NELL1/2 in acidic conditions but not at neutral pH. The NELL1/2-binding site that is occluded in neutral conditions is thought to be exposed by a conformational change of the Robo2 ectodomain upon exposure to acidic pH; however, the underlying structural mechanisms are not well understood. Here, we investigated the interaction between the immunoglobulin-like domains and fibronectin type III domains that form hairpin-like structure of the Robo2 ectodomain, and demonstrated that acidic pH attenuates the interaction between them. Alternative splicing isoforms of Robo2, which affect the conformation of the hairpin-like structure, were found to have distinct NELL1/2-binding affinities. We developed Förster resonance energy transfer-based indicators for monitoring conformational change of the Robo2 ectodomain by individually inserting donor and acceptor fluorescent proteins at its ends. These experiments revealed that the ends of the Robo2 ectodomain are close to each other in acidic conditions. By combining these findings with the results of size exclusion chromatography analysis, we suggest that, in acidic conditions, the Robo2 ectodomain has a compact conformation with a loose hairpin-like structure. These results may help elucidate the signaling mechanisms resulting from the interaction between Robo2 and NELL1/2 in acidic conditions. [ABSTRACT FROM AUTHOR]

Air pollution causes increased cardiopulmonary morbidity and mortality. Airway inflammation plays a major role in the pathophysiology of many lung diseases. Proinflammatory cytokines, such as interleukin-8 (IL-8), are responsible in part for the initiation and maintenance of airway inflammation. Asbestos exposure and particulate air pollution have been reported to stimulate the expression of IL-8 and to induce NF-κB activation. However, it is unknown whether polycyclic aromatic hydrocarbons (PAH), mainly existed in most airborne particulates, can separately induce IL-8 expression. In the present study, we investigated the effect of benzo(a)pyrene (B[a]P) and 1-nitropyrene (1-NP), two representative PAH, on IL-8 expression using ELISA and Northern blot analysis. Gel shift assay was performed to study the NF-κB activation. We have assessed the effect of adenovirus-mediated overexpression of the NF-κB inhibitor, IκBα on PAH-induced IL-8 expression in A549 cell line. Both B[a]P and 1-NP stimulated IL-8 gene expression in A549 cells. This effect was associated with induction of NF-κB activation. Overexpression of IκBα inhibited 1-NP-induced transcription of IL-8. This suggests that PAH-induced IL-8 gene regulation may be mediated by NF-κB. These data indicate that PAH alone, either B[a]P or 1-NP, is sufficient to stimulate NF-κB activation and IL-8 transcription. [Copyright &y& Elsevier]

Double-stranded RNA derived from viruses induces host immune responses. PD-L1, also known as B7-H1, is an immune-checkpoint molecule associated with the escape of viruses from host immune systems, which plays a role in the persistence of viral infection, resulting in exacerbations of underlying diseases such as asthma and chronic obstructive pulmonary disease. Interleukin (IL)-22 is produced from various immune cells and has protective properties on mucosal tissue. The binding of IL-22 to IL-22 receptor induces STAT3 activation. We investigated the effect of IL-22 on the expression in airway epithelial cells in vitro and in mouse lungs in vivo after the stimulation with an analog of viral double-stranded RNA, polyinosinic-polycytidylic acid (poly I:C). Stimulation with poly I:C upregulated PD-L1 expression on BEAS-2B cells. This upregulation of PD-L1 was attenuated by IL-22 administration. STAT3 phosphorylation was induced by IL-22 and poly I:C. Treatment of cells with STAT3 siRNA abolished the effect of IL-22 on the poly I:C-induced upregulation of PD-L1. This upregulation of PD-L1 was also attenuated by IL-11, a cytokine inducing STAT3 phosphorylation, in BEAS-2B cells. In mouse lung cells in vivo , IL-22 suppressed poly I:C-induced upregulation of PD-L1. These results suggest that IL-22 attenuates virus-induced upregulation of PD-L1 in airway epithelial cells via a STAT3-dependent mechanism. [ABSTRACT FROM AUTHOR]

Although several antibodies developed to target programmed cell death-1 (PD-1) and its ligand (PD-L1) have demonstrated great promise for the treatment of non-small cell lung cancer (NSCLC), and other malignancies, these therapeutic antibodies can cause pneumonitis. Furthermore, epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI)-induced pneumonitis was reported after treatment with anti PD-1 antibodies. We previously demonstrated that mice with naphthalene-induced airway epithelial injury developed severe gefitinib-induced pneumonitis through a neutrophil-dependent mechanism. The present study aimed to investigate whether treatment with afatinib, an EGFR-TKI that effectively targets EGFR mutation-positive NSCLC, and anti PD-1 antibodies induces pneumonitis in mice. C57BL/6J mice were treated intraperitoneally with naphthalene (200 mg/kg) on day 0. Afatinib (20 mg/kg) was administered orally on days −1 to 13. An anti-PD-1 antibody (0.2 mg/mice) was also administered intraperitoneally every 3 days from day 1 until day 13. The bronchoalveolar lavage fluid (BALF) and lung tissues were sampled on day 14. As observed previously with gefitinib, afatinib significantly increased the severity of histopathologic findings and the level of protein in BALF on day 14, compared to treatment with naphthalene alone. A combined anti-PD-1 antibody and afatinib treatment after naphthalene administration had yielded the same histopathological grade of lung inflammation as did afatinib treatment alone. Our results suggest that anti-PD-1 antibody treatment has little effect on afatinib-induced lung injury. [ABSTRACT FROM AUTHOR]

Gefitinib, an epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), is an effective therapeutic agent for non-small cell lung cancer with EGFR mutations. It can cause severe acute pneumonitis in some patients. We previously demonstrated that mice with naphthalene-induced airway epithelial injury developed severe gefitinib-induced pneumonitis and that neutrophils played important roles in the development of the disease. This study aimed to investigate the effects of the neutrophil elastase inhibitor sivelestat on gefitinib-induced pneumonitis in mice. C57BL/6J mice received naphthalene (200 mg/kg) intraperitoneally on day 0. Gefitinib (250 or 300 mg/kg) was orally administered to mice from day −1 until day 13. Sivelestat (150 mg/kg) was administered intraperitoneally from day 1 until day 13. Bronchoalveolar lavage fluid (BALF) and lung tissues were sampled on day 14. Sivelestat treatment significantly reduced the protein level, neutrophil count, neutrophil elastase activity in BALF, and severity of histopathologic findings on day 14 for mice administered with 250 mg/kg of gefitinib. Moreover, sivelestat treatment significantly improved the survival of mice administered with 300 mg/kg of gefitinib. These results indicate that sivelestat is a promising therapeutic agent for severe acute pneumonitis caused by gefitinib. [ABSTRACT FROM AUTHOR]

Background and objective As a member of the epidermal growth factor family, amphiregulin contributes to the regulation of cell proliferation. Amphiregulin was reported to be upregulated in damaged lung tissues in patients with chronic obstructive pulmonary disease and asthma and in lung epithelial cells in a ventilator-associated lung injury model. In this study, we investigated the effect of amphiregulin on lipopolysaccharide (LPS)-induced acute lung injury in mice. Methods Acute lung injury was induced by intranasal instillation of LPS in female C57BL/6 mice, and the mice were given intraperitoneal injections of recombinant amphiregulin or phosphate-buffered saline 6 and 0.5 h before and 3 h after LPS instillation. The effect of amphiregulin on apoptosis and apoptotic pathways in a murine lung alveolar type II epithelial cell line (LA-4 cells) were examined using flow cytometry and western blotting, respectively. Results Recombinant amphiregulin suppressed epithelial cell apoptosis in LPS-induced lung injury in mice. Western blotting revealed that amphiregulin suppressed epithelial cell apoptosis by inhibiting caspase-8 activity. Conclusion Amphiregulin signaling may be a therapeutic target for LPS-induced lung injury treatment through its prevention of epithelial cell apoptosis. [ABSTRACT FROM AUTHOR]

We designed a phase I trial to investigate the safety, immune responses and clinical benefits of a five-peptide cancer vaccine in combination with chemotherapy. Study subjects were patients positive for HLA-A2402 with locally advanced, metastatic, and/or recurrent gastrointestinal, lung or cervical cancer. Eighteen patients including nine cases of colorectal cancer were treated with escalating doses of cyclophosphamide 4 days before vaccination. Five HLA-A2402-restricted, tumor-associated antigen (TAA) epitope peptides from KOC1, TTK, URLC10, DEPDC1 and MPHOSPH1 were injected weekly for 4 weeks. Treatment was well tolerated without any adverse events above grade 3. Analysis of peripheral blood lymphocytes showed that the number of regulatory T cells dropped from baseline after administration of cyclophosphamide and confirmed that TAA-specific T cell responses were associated significantly with longer overall survival. This phase I clinical trial demonstrated safety and promising immune responses that correlated with vaccine-induced T-cell responses. Therefore, this approach warrants further clinical studies. [ABSTRACT FROM AUTHOR]

Highlights: [•] The presumed “at-risk” allele of CRP rs174520 was associated with an increased risk of lung cancer. [•] The presumed “at-risk” allele of IL6 rs1800796 was associated with a decreased risk of lung cancer. [•] Smoking and inflammation-related polymorphism interactions were not significant. [•] A significant interaction was observed between TNFA rs1799724 and MPO rs2333227. [Copyright &y& Elsevier]

Highlights: [•] Double-stranded RNA upregulates B7-H1 on BEAS-2B airway epithelial cells. [•] The upregulation of B7-H1 is attenuated by inhibition of PI3Kδ isoform. [•] PI3Kδ-mediated upregulation of B7-H1 is independent of NF-κB activation. [•] Inhibition of PI3Kδ may prevent persistent viral infection induced by B7-H1. [ABSTRACT FROM AUTHOR]

Abstract: The effects of tiotropium, an inhaled long-acting anti-cholinergic agent, on lung function were investigated in obstructed severe asthmatics with and without emphysematous changes despite maximal recommended treatments with high-dose of inhaled glucocorticoids and inhaled long-acting β2-agonists. We conducted a double-blind, placebo-controlled study of an inhaled single-dose of tiotropium in 18 asthmatics with emphysema and 18 without emphysema in a crossover manner. The primary efficacy outcome was the relative change in forced expiratory volume in 1 s (FEV1) from baseline to 60 min, and the secondary outcome was a relative change in FEV1 from baseline to 12 h. Subsequently, the patients were treated with tiotropium inhaled once daily for 12 weeks in an open label manner, and lung function and symptoms were evaluated. At baseline, patients with or without emphysema had a mean FEV1 of 55.9% before tiotropium and 56.8% before placebo, or 77.4% before tiotropium and 77.6% before placebo of the predicted value and were taking a mean dose of inhaled glucocorticoids of 1444 or 1422 μg/day. Among patients with emphysema, the increase from baseline FEV1 was 12.6 percentage points higher at 60 min after tiotropium than after placebo. Among patients without emphysema, the increase from baseline FEV1 was 5.4 percentage points higher at 60 min after tiotropium than after placebo. Tiotropium resulted in improved lung function and symptoms in asthmatics with and without emphysema. These findings suggest that tiotropium will provide a new strategy for the treatment of bronchial asthma and of overlapping asthma and COPD. [Copyright &y& Elsevier]

Abstract: Acute asthma exacerbations are frequently associated with respiratory viral infections. Although impaired production of type III IFNs (IFN-λs) is related to the severity of asthma exacerbation, the mechanisms underlying deficient IFN-λ production in asthma are poorly understood. Airway epithelial cells were stimulated in vitro with a synthetic mimetic of viral double-stranded RNA (dsRNA). IL-13, a crucial cytokine responsible for asthma pathogenesis, suppressed dsRNA-induced expression of IFN-λs, and JAK inhibitor AG490 prevented the suppression by IL-13. IL-13 per se did not affect IFN-λ production or the expressions of membrane dsRNA receptor TLR3 and of cytoplasmic receptors RIG-I and MDA5. IL-13-deficient mice exhibited more enhanced IFN-λ expression after intratracheal instillation of dsRNA than wild-type mice, whereas IFN-λ expression after dsRNA was absent in the mouse lungs of the OVA-induced asthma model. These findings suggest that IL-13 may be a putative cytokine suppressing IFN-λ production against airway viral infections in asthmatics. [Copyright &y& Elsevier]

Abstract: Th2 cytokines and their downstream Janus kinase (JAK)-signal transducer and activation of transcription (STAT) pathways play a critical role in allergic asthma. We studied the effects of a pan-JAK inhibitor, pyridone 6 (P6), on asthmatic responses in a mouse model and investigated the mechanism for its biological effects. Mice were sensitized and challenged by ovalbumin (OVA). P6 treatment during the challenge phase suppressed eosinophilia in bronchoalveolar lavage (BAL) fluids but did not affect airway hyperresponsiveness (AHR). To improve the efficacy of the JAK inhibitor, P6 was encapsulated in polylactic-coglycolic acid nanoparticles (P6-PLGA). P6-PLGA treatment just before OVA challenge suppressed both airway eosinophilia and AHR. Although the IL-13 levels in BAL fluids and the OVA-specific IgE levels in serum after the challenge phase treatment with P6-PLGA were similar to those after a sham treatment, the eotaxin levels in BAL fluids and lung mCLCA3/Gob-5 expression were decreased in P6-PLGA-treated mice. Interestingly, the local IL-13 levels and serum OVA-specific IgE were decreased, while IL-17-producing T cells were increased by P6-PLGA treatment during the sensitization plus challenge phases. In vitro, P6 strongly suppressed the differentiation of Th2 from naive CD4 T cells, but it partly enhanced Th17 differentiation. P6 potently suppressed IL-13-mediated STAT6 activation and mCLCA3/Gob-5 expression in mouse tracheal epithelial cells. These findings suggest that the JAK inhibitor P6 suppresses asthmatic responses by inhibiting Th2 inflammation and that application of PLGA nanoparticles improves the therapeutic potency of P6. [ABSTRACT FROM AUTHOR]

Abstract: Acidic mammalian chitinase is upregulated in response to allergen exposure in the lung. We investigated the effects of chitinase inhibitors, allosamidin (Allo) and demethylallosamidin (Dma), on asthmatic responses. Mice were subjected to IL-13 instillation into the airways or to ovalbumin sensitization plus exposure with or without treatment of Allo or Dma. Airway hyperresponsiveness (AHR) and inflammation were evaluated. Allo and Dma attenuated airway eosinophilia and the upregulation of eotaxin after IL-13 instillation, while Dma, but not Allo, suppressed AHR in IL-13-induced asthma. Allo or Dma suppressed the elevated chitinase activity in BAL fluids after IL-13 to similar levels. The bronchoprotective PGE2 levels in BAL fluids were elevated after IL-13 instillation. Allo, but not Dma, suppressed the overproduction of PGE2 and the expression of COX-2 and PGE synthase-1 induced by IL-13. In ovalbumin-induced asthma, Dma suppressed AHR more strongly than Allo. These findings suggest that Dma attenuates asthmatic responses induced by IL-13 without affecting PGE2 synthesis. Dma may have potential as therapeutic agents for asthma. [Copyright &y& Elsevier]

Abstract: Legionella pneumophila is one of the most important pathogens which cause community-acquired pneumonia. Although TNF-α is considered to play an important role in response to bacteria, the role of the TNF-α receptor on L. pneumophila infection remains to be elucidated. To investigate this, we infected TNF receptor deficient mice with L. pneumophila. L. pneumophila was inoculated intranasally into TNF receptor (TNFR)-1-knock-out mice or TNFR2-knock-out mice. The mortality rate, histology of the lung, bacterial growth in the lung, and bronchoalveolar lavage (BAL) fluids were investigated. The bacterial growth of L. pneumophila in the macrophages was also studied. Almost all the mice survived after an intranasal inoculation of 1×106 CFU/head of L. pneumophila, but more than 90% mice were killed after inoculation of 1×108 CFU/head of L. pneumophila. In the case of TNFR1-knock-out mice and TNFR2-knock-out mice, a high mortality rate was observed after inoculation of 1×107 CFU/head of L. pneumophila in comparison to wild-type mice. The lung histology from both the TNFR1-knock-out mice documented severe lung injury at day 3 after inoculation. The clearance of L. pneumophila in the lung of the TNFR1-knock-out mice was slower than those from both the TNFR2-knock-out mice and the wild-type mice. Moreover, L. pneumophila growth in the peritoneal macrophages from the TNFR1-knock-out mice was observed. Interestingly, a lack of neutrophils accumulation in the BAL fluids and a dysregulation of cytokines (IFN-γ, interleukin-12, and TNF-α) were observed in the TNFR1-knock-out mice. On the contrary, large accumulation of neutrophils in BAL fluids was observed in TNFR2-knock-out mice. These data suggested that a TNFR1 deficiency led to a compromise of the innate immunity against L. pneumophila, while a TNFR2 deficiency induced an excessive inflammatory response and resulted in death. The present study confirmed that TNFR1 and TNFR2 play a crucial, but different role in the control of L. pneumophila-induced mortality. [Copyright &y& Elsevier]

Abstract: Oxidative stress plays a critical role in the development of pulmonary fibrosis. However, the effects of treatment with anti-oxidant agents against pulmonary fibrosis have not yet been thoroughly investigated. In this study, the effect of MCI-186, a novel free radical scavenger, on bleomycin-induced pulmonary fibrosis was investigated. Bleomycin (0.05units/mouse) was administered intratracheally into C57Bl/6 mice. MCI-186 was given to bleomycin-treated mice intraperitoneally from (i) day −3 to day 7, or from (ii) day 10 to day 28 after bleomycin administration in successive days. At 28 days after bleomycin administration, pulmonary fibrosis was then assessed by lung histology and hydroxyproline. MCI-186 inhibited H2O2-induced DNA damage in bronchial epithelium in vitro. MCI-186 decreased the lipid peroxide content, a marker for DNA damage, in the lung and reduced 8-OHdG positive cells in the lung in vivo. During the early period (day −3 to day 7) administration, MCI-186 partially attenuated bleomycin-induced pulmonary fibrosis. However, during the late period (day 10 to day 28) MCI-186 exacerbated pulmonary fibrosis, based on the histology and hydroxyproline content. In this condition, MCI-186 in the late period decreased the number of apoptosis cells induced by bleomycin, and therefore it might contribute to the deterioration of pulmonary fibrosis. These data indicate that MCI-186, radical scavenger, has a biphasic effect on bleomycin-induced pulmonary fibrosis in mice. Careful attention should be paid before clinical application of new remedies for pulmonary fibrosis. [Copyright &y& Elsevier]

Abstract: Matrix metalloproteinases (MMPs) expression plays a critical role in extracellular matrix deposition. Although several pieces of evidence have so far indicated that gelatinase contributes to the development of pulmonary fibrosis, the role of collagenase remains uncertain. In this study, we attempted to determine the role of collagenase using a bleomycin-induced pulmonary fibrosis model. Bleomycin was instilled into mice intratracheally. Bronchoalveolar lavage fluid (BAL) specimens were analyzed for gelatin and casein zymography, as well as by immunoblotting. The histology of the lungs and hydroxyproline contents were also assessed. MMPs inhibitor, CGS27023A, was simultaneously orally administered. Collagenases were induced in BAL fluids after bleomycin administration based on the data of zymography and immunohistochemistry. The co-administration of MMPs inhibitor, CGS27023A, with bleomycin resulted in worsening pulmonary fibrosis with inhibition of collagenase. The worsening of pulmonary fibrosis was mainly induced by CGS27023A administration in the late phase of bleomycin-induced pulmonary fibrosis development, but not in the early phase. The present data indicated that collagenase plays an anti-fibrotic role in the bleomycin-induced pulmonary fibrosis model. Collagenase has a greater effect on fibrosis phase than inflammatory phase in the bleomycin-induced pulmonary fibrosis in the mice. [Copyright &y& Elsevier]

Abstract: Tumor necrosis factor (TNF)-α is a key pro-inflammatory cytokine, thought to be important in the pathogenesis of pulmonary emphysema. TNF-α overexpression in the lung leads to the phenotypic features of pulmonary emphysema, pulmonary hypertension, and right ventricular hypertrophy in mice bred in Denver, 5240feet/1600m of altitude. This study hypothesized that the altitude could affect the development of pulmonary emphysema as well as pulmonary hypertension. To investigate the effect of the altitude, TNF-α transgenic mice were bred at sea level, Fukuoka, Japan. The pulmonary physiology and histology demonstrated similar development of pulmonary emphysema, compared to the mice bred in Denver. With respect to pulmonary hypertension, right ventricular hypertrophy was attenuated. Interestingly, mortality rate was significant lower in the mice bred at sea level. In contrast with the results in Denver, a significant decrease of vascular endothelial growth factor (VEGF) and its receptors expression was not found. From these data, we consider that the altitude affects development of pulmonary hypertension through the expression of VEGF and its receptors. In contrast, the effect of altitude was not clear regarding the development of pulmonary emphysema. [Copyright &y& Elsevier]

Abstract: B7-DC is a costimulatory molecule belonging to the B7 family. We previously found that treatment with anti-B7-DC mAb during the effector phase enhances asthma phenotypes in mice. We investigated the mechanisms of B7-DC induction and how B7-DC regulates asthma phenotypes. In allergen-challenged IFN-γ-deficient mice, anti-B7-DC mAb failed to enhance the asthma phenotypes although the induction of B7-DC on dendritic cells of the mice was comparable with that on dendritic cells of wild-type mice. B7-DC on dendritic cells was up-regulated by IL-13 in vitro. The induction of B7-DC on dendritic cells after allergen challenge was attenuated by blockade of IL-13 in vivo. The asthma phenotypes were enhanced in B7-DC-deficient mice, more than in wild-type mice. The enhancement was concurrent with the down-regulation of IFN-γ and up-regulation of IL-13. These results suggest that B7-DC induced by IL-13 works as a feedback regulator by up-regulating IFN-γ production during the effector phase of allergic asthma. [Copyright &y& Elsevier]

Abstract: Antibiotics can have a biological effect apart from their anti-bacterial effect. We hypothesized that doxycycline could attenuate acute lung injury through its biological effect. Lipopolysaccharide or doxycycline-resistant Streptococcus pneumoniae was administered intratracheally into mice with the co-administration of doxycycline. Thereafter, the lung pathology, intraalveolar inflammatory cells, bacterial number, and matrix metalloproteinases were investigated. Matrix metalloproteinases, neutrophil migration, and alveolar destruction were induced by lipopolysaccharide. Doxycycline was thus found to improve all of these symptoms. In addition, an inhibitor of matrix metalloproteinases, CGS27023A, attenuated lipopolysaccharide-induced lung injury. Doxycycline also attenuated the lung injury induced by doxycycline-resistant S. pneumoniae and improved the mortality rate although the bacterial number in the lung did not change. Our data indicated that doxycycline could attenuate acute lung injury through a biological effect that was different from its antibiotic effect. [Copyright &y& Elsevier]

Abstract: IL-13 receptor α2 (IL-13Rα2) has been postulated to be a decoy receptor. The precise mechanisms for the generation of soluble IL-13Rα2 and the biological activity of the endogenous soluble form have not been reported. Hypothesizing that the soluble form of IL-13Rα2 is generated by proteolytic cleavage of membrane-bound receptors, we transfected human airway epithelial cells with adenoviral vectors encoding full-length IL-13Rα2. Eotaxin production from IL-13Rα2-transfected cells was suppressed, and soluble IL-13Rα2 in the supernatants was increased time-dependently after the transfection. The transfer of conditioned media from IL-13Rα2-transfected cells inhibited IL-13-induced eotaxin production and STAT6 phosphorylation in non-transfected cells. PMA enhanced the release of soluble IL-13Rα2, and metalloprotease inhibitors inhibited this release. These findings suggest that airway epithelial cells with upregulation of membrane-bound IL-13Rα2 secrete soluble IL-13Rα2 into its supernatant, causing the autocrine and paracrine downregulation of the IL-13/STAT6 signal. Metalloprotease(s) are responsible for the proteolytic cleavage of cell surface IL-13Rα2. [Copyright &y& Elsevier]

Abstract: Surfactant protein A (SP-A) and surfactant protein D (SP-D) are important components of innate immunity that can modify the inflammatory response. However, alterations and regulation of SP-A and SP-D in acute and chronic inflammation are not well defined. In addition, serum SP-D may serve as a biomarker of lung inflammation. We determined the expression of SP-A and SP-D in murine models. To study acute inflammation, we instilled bleomycin intrabronchially. To study chronic lung inflammation, we used a transgenic mouse that overexpresses tumor necrosis factor (TNF)-α under the control of the SP-C promoter. These mice have a chronic mononuclear cell infiltration, airspace enlargement, pulmonary hypertension, and focal pulmonary fibrosis. In acute inflammation model, levels of mRNA for all surfactant proteins were reduced after bleomycin administration. However, serum SP-D was increased from days 7 to 28 after instillation. In chronic inflammation model, SP-D mRNA expression was increased, whereas the expression of SP-A, SP-B and SP-C was reduced. Both serum and lung SP-D concentrations were increased in chronic lung inflammation. These data clarified profile of SP-A and SP-D in acute and chronic inflammation and indicated that serum SP-D can serve as a biomarker of lung inflammation in both acute and chronic lung injury in mice. [Copyright &y& Elsevier]

Abstract: Viral infection in the airway provokes various immune responses, including Th1 and Th2 responses, which are partly initiated by double-stranded RNA (dsRNA), a viral product for its replication. B7-H1 (PD-L1) and B7-DC (PD-L2) are B7-family molecules that bind to programmed death-1 (PD-1) on lymphocytes and are implicated in peripheral tolerance. We investigated the effect of dsRNA on the expression of B7-H1 and B7-DC on airway epithelial cell lines. B7-H1 and B7-DC were constitutively expressed on the cells, and their expression was profoundly upregulated by stimulation with an analog of viral dsRNA, polyinosinic–polycytidylic acid. B7-H1 and B7-DC were also upregulated by stimulation with IFN-γ, IL-13, and the supernatant from T cell clones. A relatively high concentration of dexamethasone (1μM) was required to suppress the upregulation of B7-H1 or B7-DC. These results suggest that epithelial B7-H1 and B7-DC play a role in virus-associated immune responses in the airways. [Copyright &y& Elsevier]