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Search: L773:1522 1504 OR L773:1040 0605

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1.
  • Abreu, Soraia Carvalho, et al. (author)
  • Differential effects of the cystic fibrosis lung inflammatory environment on mesenchymal stromal cells
  • 2020
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1040-0605 .- 1522-1504.
  • Journal article (peer-reviewed)abstract
    • Growing evidence demonstrates that human mesenchymal stromal cells (MSCs) modify their in vivo anti-inflammatory actions depending on the specific inflammatory environment encountered. Understanding this better is crucial to refine MSC-based cell therapies for lung and other diseases. Using acute exacerbations of cystic fibrosis (CF) lung disease as a model, the effects of ex vivo MSC exposure to clinical bronchoalveolar lavage fluid (BALF) samples, as a surrogate for the in vivo clinical lung environment, on MSC viability, gene expression, secreted cytokines, and mitochondrial function was compared to effects of BALF collected from healthy volunteers. CF BALF samples which cultured positive for Aspergillus sp. (Asp) induced rapid MSC death, usually within several hours of exposure. Further analyses suggested the fungal toxin gliotoxin as a potential mediator contributing to CF BALF-induced MSC death. RNA sequencing analyses of MSCs exposed to either Asp+ or Asp- CF BALF samples identified a number of differentially expressed transcripts, including those involved in interferon-signaling, anti-microbial gene expression, and cell death. Toxicity did not correlate with bacterial lung infections. These results suggest that the potential use of MSC-based cell therapies for CF or other lung diseases may not be warranted in the presence of Aspergillus.
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2.
  • Abreu, Soraia Carvalho, et al. (author)
  • Lung Inflammatory Environments Differentially Alter Mesenchymal Stromal Cell Behavior
  • 2019
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 317:6, s. 823-831
  • Journal article (peer-reviewed)abstract
    • Mesenchymal stromal (stem) cells (MSCs) are increasingly demonstrated to ameliorate experimentally-induced lung injuries through disease-specific anti-inflammatory actions, thus suggesting that different in vivo inflammatory environments can influence MSC actions. To determine the effects of different representative inflammatory lung conditions, human bone marrow-derived MSCs (hMSCs) were exposed to in vitro culture conditions from bronchoalveolar lavage fluid (BALF) samples obtained from patients with either the acute respiratory distress syndrome (ARDS) or with other lung diseases including acute respiratory exacerbations of cystic fibrosis (CF) (non-ARDS). hMSCs were subsequently assessed for time- and BALF concentration-dependent effects on mRNA expression of selected pro- and anti-inflammatory mediators, and for overall patterns of gene and mRNA expression. Both common and disease specific-patterns were observed in gene expression of different hMSC mediators, notably interleukin (IL)-6. Conditioned media obtained from non-ARDS BALF-exposed hMSCs was more effective in promoting an anti-inflammatory phenotype in monocytes than was conditioned media from ARDS BALF-exposed hMSCs. Neutralizing IL-6 in the conditioned media promoted generation of anti-inflammatory monocyte phenotype. These results demonstrated that different lung inflammatory environments differentially alter hMSC behavior. Further identification of these interactions and the driving mechanisms may influence clinical use of MSCs for treating lung diseases.
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3.
  • Andersson, Anders, et al. (author)
  • Effects of Tobacco Smoke on IL-16 in CD8+ Cells from Human Airways and Blood: a Key Role for Oxygen Free Radicals?
  • 2011
  • In: AJP - Lung cellular and molecular physiology. - : American Physiological Society. - 1522-1504. ; 300:1
  • Journal article (peer-reviewed)abstract
    • Chronic exposure to tobacco smoke leads to an increase in the frequency of infections and in CD8(+) and CD4(+)cells as well as the CD4(+) chemo-attractant cytokine IL-16 in the airways. Here, we investigated whether tobacco smoke depletes intracellular IL-16 protein and inhibits de novo production of IL-16 in CD8(+) cells from human airways and blood, while at the same time increasing extracellular IL-16 and whether oxygen free radicals (OFR) are involved. Intracellular IL-16 protein in CD8(+) cells and mRNA in all cells was decreased in bronchoalveolar lavage (BAL) samples from chronic smokers. This was also the case in human blood CD8(+) cells exposed to water-soluble tobacco smoke components in vitro; in which oxidized proteins were markedly increased. Extracellular IL-16 protein was increased in cell-free BAL fluid from chronic smokers and in human blood CD8(+) cells exposed to water-soluble tobacco smoke components in vitro. This was not observed in occasional smokers after short-term exposure to tobacco smoke. A marker of activation (CD69) was slightly increased whereas other markers of key cellular functions (membrane integrity, apoptosis and proliferation) in human blood CD8(+) cells in vitro were negatively affected by water-soluble tobacco smoke components. An OFR scavenger prevented these effects whereas a protein synthesis inhibitor, a beta-adrenoceptor, a glucocorticoid receptor agonist, a phosphodiesterase, a calcineurin phosphatase and a caspase-3 inhibitor did not. In conclusion, tobacco smoke depletes preformed intracellular IL-16 protein, inhibits its de novo synthesis and distorts key cellular functions in human CD8(+) cells. OFR may play a key role in this context.
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4.
  • Anh, TNH, et al. (author)
  • Dendritic cell functional properties in a three-dimensional tissue model of human lung mucosa
  • 2012
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 302:2, s. L226-L237
  • Journal article (peer-reviewed)abstract
    • In lung tissue, dendritic cells (DC) are found in close association with the epithelial cell layer, and there is evidence of DC regulation by the epithelium; that epithelial dysfunction leads to overzealous immune cell activation. However, dissecting basic mechanisms of DC interactions with epithelial cells in human tissue is difficult. Here, we describe a method to generate a three-dimensional organotypic model of the human airway mucosa in which we have implanted human DC. The model recapitulates key anatomical and functional features of lung mucosal tissue, including a stratified epithelial cell layer, deposition of extracellular matrix proteins, and the production of tight junction and adherence junction proteins. Labeling of fixed tissue model sections and imaging of live tissue models also revealed that DC distribute in close association with the epithelial layer. As functional properties of DC may be affected by the local tissue microenvironment, this system provides a tool to study human DC function associated with lung mucosal tissue. As an example, we report that the lung tissue model regulates the capacity of DC to produce the chemokines CCL17, CCL18, and CCL22, leading to enhanced CCL18 expression and reduced CCL17 and CCL22 expression. This novel tissue model thus provides a tool well suited for a wide range of studies, including those on the regulation of DC functional properties within the local tissue microenvironment during homeostasis and inflammatory reactions.
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5.
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6.
  • Basic, Vladimir Tomislav, et al. (author)
  • Exposure to cigarette smoke induces overexpression of von Hippel-Lindau tumor suppressor in mouse skeletal muscle
  • 2012
  • In: American Journal of Physiology - Lung cellular and Molecular Physiology. - Bethesda, USA : American Physiological Society. - 1040-0605 .- 1522-1504. ; 303:6, s. L519-L527
  • Journal article (peer-reviewed)abstract
    • Cigarette smoke (CS) is a well established risk factor in the development of chronic obstructive pulmonary disease (COPD). In contrast, the extent to which CS exposure contributes to the development of the systemic manifestations of COPD, such as skeletal muscle dysfunction and wasting remains largely unknown. Decreased skeletal muscle capillarization has been previously reported in early stages of COPD and might play an important role in the development of COPD-associated skeletal muscle abnormalities. To investigate the effects of chronic CS exposure on skeletal muscle capillarization and exercise tolerance a mouse model of CS exposure was used. The129/SvJ mice were exposed to CS for 6 months, and the expression of putative elements of the hypoxia-angiogenic signaling cascade as well as muscle capillarization were studied. Additionally, functional tests assessing exercise tolerance/endurance were performed in mice. Compared to controls, skeletal muscles from CS-exposed mice exhibited significantly enhanced expression of von Hippel-Lindau tumor suppressor (VHL), ubiquitin-conjugating enzyme E2D1 (UBE2D1) and prolyl hydroxylase-2 (PHD2). In contrast, hypoxia-inducible factor-1 (HIF1-α) and vascular endothelial growth factor (VEGF) expression was reduced. Furthermore, reduced muscle fiber cross-sectional area, decreased skeletal muscle capillarization, and reduced exercise tolerance were also observed in CS-exposed animals. Taken together, the current results provide evidence linking chronic CS exposure and induction of VHL expression in skeletal muscles leading towards impaired hypoxia-angiogenesis signal transduction, reduced muscle fiber cross-sectional area and decreased exercise tolerance.
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7.
  • Bein, K, et al. (author)
  • Genetic determinants of ammonia-induced acute lung injury in mice
  • 2021
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 320:1, s. L41-L62
  • Journal article (peer-reviewed)abstract
    • In this study, a genetically diverse panel of 43 mouse strains was exposed to ammonia, and genome-wide association mapping was performed employing a single-nucleotide polymorphism (SNP) assembly. Transcriptomic analysis was used to help resolve the genetic determinants of ammonia-induced acute lung injury. The encoded proteins were prioritized based on molecular function, nonsynonymous SNP within a functional domain or SNP within the promoter region that altered expression. This integrative functional approach revealed 14 candidate genes that included Aatf, Avil, Cep162, Hrh4, Lama3, Plcb4, and Ube2cbp, which had significant SNP associations, and Aff1, Bcar3, Cntn4, Kcnq5, Prdm10, Ptcd3, and Snx19, which had suggestive SNP associations. Of these genes, Bcar3, Cep162, Hrh4, Kcnq5, and Lama3 are particularly noteworthy and had pathophysiological roles that could be associated with acute lung injury in several ways.
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8.
  • Berg, T, et al. (author)
  • Ectopic expression of C/EBPalpha in the lung epithelium disrupts late lung development
  • 2006
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1040-0605 .- 1522-1504. ; 291:4, s. L683-L693
  • Journal article (peer-reviewed)abstract
    • The lung develops from the endoderm through a process of branching morphogenesis. This process is highly active during the pseudoglandular stage of lung development and continues into the canalicular stage, resulting in the formation of terminal sacs. CCAAT/enhancer binding proteins (C/EBPs) are transcription factors regulating central aspects of differentiation and proliferation. We report here the developmental expression of C/EBPα, -β, and -δ in the lung. C/EBPα exhibits a dynamic expression pattern and is first detected during the late pseudoglandular stage. At this stage, expression is observed in a subset of epithelial cells in the distal parts of the branching tubules. The expression of C/EBPα is confined to nonproliferating cells. To examine the role of C/EBPα in lung development, we generated transgenic mice ectopically expressing C/EBPα in the lung epithelium using the human surfactant protein C promoter. Lungs from these mice were of normal size but exhibited a phenotype characterized by fewer and larger developing epithelial tubules, indicating that the branching process was affected. No effects on overall proliferation or cellular differentiation were observed. When this phenotype was compared with that of mice carrying a targeted mutation of the Cebpa gene, the Cebpa−/−mice exhibited a similar developmental phenotype. In conclusion, our results show a role for C/EBPα in lung development and suggest a function in the later stages of lung branching morphogenesis.
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9.
  • Cassel, TN, et al. (author)
  • C/EBP transcription factors in the lung epithelium
  • 2003
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1040-0605 .- 1522-1504. ; 285:4, s. L773-L781
  • Journal article (peer-reviewed)abstract
    • During recent years, the biological roles of CCAAT/enhancer binding proteins (C/EBPs) in the lung have started to be uncovered. C/EBPs form a family within the basic region-leucine zipper class of transcription factors. In the lung epithelium C/EBPα, -β, and -δ are expressed. Lung-specific target genes for these transcription factors include the surfactant proteins A and D, the Clara cell secretory protein, and the P450 enzyme CYP2B1. As more information is gathered, a picture is emerging in which C/EBPα has a role in regulating proliferation as well as differentiation-dependent gene expression, whereas C/EBPβ and -δ, in addition to a partly overlapping role in regulating expression of differentiation markers, also seem to be involved in responses to injury and hormones.
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10.
  • Chang, Ya-Ting, et al. (author)
  • Antenatal imatinib treatment reduces pulmonary vascular remodeling in a rat model of congenital diaphragmatic hernia
  • 2012
  • In: American Journal of Physiology - Lung cellular and Molecular Physiology. - : American Physiological Society. - 1040-0605 .- 1522-1504. ; 302:11, s. L1159-L1166
  • Journal article (peer-reviewed)abstract
    • The pathophysiology of congenital diaphragmatic hernia (CDH) is constituted by pulmonary hypoplasia and pulmonary hypertension (PH). We previously reported successful treatment with imatinib of a patient with CDH. This study examines the effect of antenatal imatinib administration on the pulmonary vasculature in a rat model of CDH. Pregnant rats were given nitrofen to induce CDH. Controls were given olive oil. Half of the CDH fetuses and half of the controls were treated with imatinib antenatally E17-E21, rendering four groups: Control, Control+Imatinib, CDH, and CDH+Imatinib. Lung sections were obtained for morphometry and immunohistochemistry, and protein was purified for Western blot. Effects of nitrofen and imatinib on Ki-67, caspase-3, PDGF-B, and PDGF receptors were analyzed. Imatinib significantly reduced medial wall thickness in pulmonary arteries of rats with CDH. It also normalized lumen area and reduced the proportion of fully muscularized arteries. Imatinib also caused medial thinning in the control group. Cell proliferation was increased in CDH, and this proliferation was significantly reduced by imatinib. PDGF-B and PDGFR-beta were upregulated in CDH, and imatinib treatment resulted in a downregulation. PDGFR-alpha remained unchanged in CDH but was significantly downregulated by imatinib. Antenatal imatinib treatment reduces development of medial wall thickness and restores lumen area in pulmonary arteries in nitrofen-induced CDH. The mechanism is reduced cell proliferation. Imatinib is an interesting candidate for antenatal therapy for PH in CDH, but potential side effects need to be investigated and more specific targeting of PDGF signaling is needed.
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11.
  • Fakih, Dalia, et al. (author)
  • Normal murine respiratory tract has its mucus concentrated in clouds based on the Muc5b mucin
  • 2020
  • In: American Journal of Physiology-Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1040-0605 .- 1522-1504. ; 318:6
  • Journal article (peer-reviewed)abstract
    • The organization of the normal airway mucus system differs in small experimental animals from that in humans and large mammals. To address normal murine airway mucociliary clearance, Alcian blue-stained mucus transport was measured ex vivo on tracheal tissues of naive C57BL/6, Muc5b(-/-), Muc5ac(-/-), and EGFP-tagged Muc5b reporter mice. Close to the larynx with a few submucosal glands, the mucus appeared as thick bundles. More distally in the trachea and in large bronchi, Alcian blue-stained mucus was organized in cloud-like formations based on the Muc5b mucin. On tilted tissue, the mucus clouds moved upward toward the larynx with an average velocity of 12 mu m/s compared with 20 mu m/s for beads not associated with clouds. In Muc5ac(-/-) mice, Muc5b formed mucus strands attached to the tissue surface, while in Muc5b(-/-) mice, Muc5ac had a more variable appearance. The normal mouse lung mucus thus appears as discontinuous clouds, clearly different from the stagnant mucus layer in diseased lungs.
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12.
  • Fredriksson, K, et al. (author)
  • Red blood cells increase secretion of matrix metalloproteinases from human lung fibroblasts in vitro
  • 2006
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1040-0605 .- 1522-1504. ; 290:2, s. L326-L333
  • Journal article (peer-reviewed)abstract
    • Tissue remodeling is an important process in many inflammatory and fibrotic lung disorders. RBC may in these conditions interact with extracellular matrix (ECM). Fibroblasts can produce and secrete matrix components, matrix-degrading enzymes (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Imbalance in matrix synthesis/degradation may result in rearrangement of tissue architecture and lead to diseases such as emphysema or fibrosis. Neutrophil elastase (NE), a protease released by neutrophils, is known to activate MMP. We hypothesized that RBC can stimulate secretion of MMPs from human lung fibroblasts and that NE can augment this effect. Human fetal lung fibroblasts were cultured in floating collagen gels with or without RBC. After 4 days, the culture medium was analyzed with gelatin zymography, Western blot, and ELISA for MMP-1, -2, -3 and TIMP-1, -2. RBC augmented NE-induced fibroblast-mediated collagen gel contraction compared with NE alone (18.4 ± 1.6%, 23.7 ± 1.4% of initial gel area, respectively). A pan-MMP inhibitor (GM-6001) completely abolished the stimulating effect of NE. Gelatin zymography showed that RBC stimulated MMP-2 activity and that NE enhanced conversion to the active form. Addition of GM-6001 completely inhibited MMP-2 activity in controls, whereas it only partially altered RBC-induced MMP activity. Western blot confirmed the presence of MMP-1 and MMP-3 in fibroblasts stimulated with RBC, and ELISA confirmed increased concentrations of pro-MMP-1. We conclude that stimulation of MMP secretion by fibroblasts may explain the ability of RBC to augment fibroblast-mediated collagen gel contraction. This might be a potential mechanism by which hemorrhage in inflammatory conditions leads to ECM remodeling.
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13.
  • Fuchs, B, et al. (author)
  • Mast cell engraftment of the peripheral lung enhances airway hyperresponsiveness in a mouse asthma model
  • 2012
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 303:12, s. L1027-L1036
  • Journal article (peer-reviewed)abstract
    • Allergic asthma is a chronic inflammatory disease, characterized by airway hyperresponsiveness (AHR), inflammation, and tissue remodeling, in which mast cells play a central role. In the present study, we analyzed how mast cell numbers and localization influence the AHR in a chronic murine model of asthma. C57BL/6 (wild-type) and mast cell-deficient B6.Cg- KitW−shmice without (Wsh) and with (Wsh+MC) mast cell engraftment were sensitized to and subsequently challenged with ovalbumin for a 91-day period. In wild-type mice, pulmonary mast cells were localized in the submucosa of the central airways, whereas the more abundant mast cells in Wsh+MC mice were found mainly in the alveolar parenchyma. In Wsh+MC, ovalbumin challenge induced a relocation of mast cells from the perivascular space and central airways to the parenchyma. Allergen challenge caused a similar AHR in wild-type and Wsh mice in the resistance of the airways and the pulmonary tissue. In Wsh+MC mice the AHR was more pronounced. The elevated functional responses were partly related to the numbers and localization of connective tissue-type mast cells in the peripheral pulmonary compartments. A mast cell-dependent increase in IgE and IL-33 together with impairment of the IL-23/IL-17 axis was evoked in Wsh and Wsh+MC mice by allergen challenge. This study shows that within the same chronic murine asthma model the development of AHR can be both dependent and independent of mast cells. Moreover, the spatial distribution and number of pulmonary mast cells determine severity and localization of the AHR.
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14.
  • Gouveia, Maria Leonor Seguardo, et al. (author)
  • Lung developmental arrest caused by PDGF-A deletion : consequences for the adult mouse lung
  • 2020
  • In: American Journal of Physiology - Lung cellular and Molecular Physiology. - : AMER PHYSIOLOGICAL SOC. - 1040-0605 .- 1522-1504. ; 318:4, s. L831-L843
  • Journal article (peer-reviewed)abstract
    • PDGF-A is a key contributor to lung development in mice. Its expression is needed for secondary septation of the alveoli and deletion of the gene leads to abnormally enlarged alveolar air spaces in mice. In humans, the same phenotype is the hallmark of bronchopulmonary dysplasia (BPD), a disease that affects premature babies and may have long lasting consequences in adulthood. So far, the knowledge regarding adult effects of developmental arrest in the lung is limited. This is attributable to few follow-up studies of BPD survivors and lack of good experimental models that could help predict the outcomes of this early age disease for the adult individual. In this study, we used the constitutive lung-specific Pdgfa deletion mouse model to analyze the consequences of developmental lung defects in adult mice. We assessed lung morphology, physiology, cellular content, ECM composition and proteomics data in mature mice, that perinatally exhibited lungs with a BPD-like morphology. Histological and physiological analyses both revealed that enlarged alveolar air spaces remained until adulthood, resulting in higher lung compliance and higher respiratory volume in knockout mice. Still, no or only small differences were seen in cellular, ECM and protein content when comparing knockout and control mice. Taken together, our results indicate that Pdgfa deletion-induced lung developmental arrest has consequences for the adult lung at the morphological and functional level. In addition, these mice can reach adulthood with a BPD-like phenotype, which makes them a robust model to further investigate the pathophysiological progression of the disease and test putative regenerative therapies.
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15.
  • Gutbier, Birgitt, et al. (author)
  • Moraxella catarrhalis induces an immune response in the murine lung which is independent of human CEACAM5 expression and long-term smoke exposure.
  • 2015
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 309:3, s. 250-261
  • Journal article (peer-reviewed)abstract
    • In patients with chronic obstructive pulmonary disease (COPD), Moraxella catarrhalis infection of the lower airways is associated with chronic colonization and inflammation during stable disease and acute exacerbations. Chronic smoke exposure induces chronic inflammation and impairs mucociliary clearance, thus contributing to bacterial colonization of the lower airways in COPD patients. The human-specific carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 5, expressed in human airways, has been shown to contribute to epithelial colonization of CEACAM-binding pathogens. To investigate the impact of CEACAM5 expression on pulmonary M. catarrhalis colonization, we infected mice transgenic for human CEACAM5 (hCEACAM5) and wild type mice intratracheally with M. catarrhalis with or without preceding smoke exposure and analyzed bacterial colonization and local and systemic inflammation. Our results show that airway infection with M. catarrhalis accelerated acute local but not systemic inflammation, albeit independent of hCEACAM5 expression. Long-term smoke exposure alone or prior to M. catarrhalis infection did not contribute to increased local or systemic inflammation. No difference was found in pulmonary clearance of M. catarrhalis in hCEACAM5-transgenic mice compared to wild type mice. Smoke exposure neither altered time nor extent of persistence of M. catarrhalis in the lungs of both genotypes. In conclusion, M. catarrhalis induced a local acute immune response in murine airways. Neither hCEACAM5- expression nor chronic smoke exposure nor a combination of both was sufficient as prerequisites for the establishment of chronic M. catarrhalis colonization. Our results demonstrate the difficulties in mirroring conditions of chronic airways colonization of M. catarrhalis in a murine model.
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16.
  • Hasan, Zirak, et al. (author)
  • Geranylgeranyl transferase regulates CXC chemokine formation in alveolar macrophages and neutrophil recruitment in septic lung injury
  • 2013
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 304:4, s. 221-229
  • Journal article (peer-reviewed)abstract
    • Hasan Z, Rahman M, Palani K, Syk I, Jeppsson B, Thorlacius H. Geranylgeranyl transferase regulates CXC chemokine formation in alveolar macrophages and neutrophil recruitment in septic lung injury. Am J Physiol Lung Cell Mol Physiol 304: L221-L229, 2013. First published December 14, 2012; doi:10.1152/ajplung.00199.2012.-Overwhelming accumulation of neutrophils is a significant component in septic lung damage, although the signaling mechanisms behind neutrophil infiltration in the lung remain elusive. In the present study, we hypothesized that geranylgeranylation might regulate the inflammatory response in abdominal sepsis. Male C57BL/6 mice received the geranylgeranyl transferase inhibitor, GGTI-2133, before cecal ligation and puncture (CLP). Bronchoalveolar lavage fluid and lung tissue were harvested for analysis of neutrophil infiltration, as well as edema and CXC chemokine formation. Blood was collected for analysis of Mac-1 on neutrophils and CD40L on platelets. Gene expression of CXC chemokines, tumor necrosis factor-alpha (TNF-alpha), and CCL2 chemokine was determined by quantitative RT-PCR in isolated alveolar macrophages. Administration of GGTI-2133 markedly decreased CLP-induced infiltration of neutrophils, edema, and tissue injury in the lung. CLP triggered clear-cut upregulation of Mac-1 on neutrophils. Inhibition of geranylgeranyl transferase reduced CLP-evoked upregulation of Mac-1 on neutrophils in vivo but had no effect on chemokine-induced expression of Mac-1 on isolated neutrophils in vitro. Notably, GGTI-2133 abolished CLP-induced formation of CXC chemokines, TNF-alpha, and CCL2 in alveolar macrophages in the lung. Geranylgeranyl transferase inhibition had no effect on sepsis-induced platelet shedding of CD40L. In addition, inhibition of geranylgeranyl transferase markedly decreased CXC chemokine-triggered neutrophil chemotaxis in vitro. Taken together, our findings suggest that geranylgeranyl transferase is an important regulator of CXC chemokine production and neutrophil recruitment in the lung. We conclude that inhibition of geranylgeranyl transferase might be a potent way to attenuate acute lung injury in abdominal sepsis.
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17.
  • Hogmalm, Anna, 1981, et al. (author)
  • IL-1β expression in the distal lung epithelium disrupts lung morphogenesis and epithelial cell differentiation in fetal mice.
  • 2014
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 306:1
  • Journal article (peer-reviewed)abstract
    • Perinatal inflammation and the inflammatory cytokine IL-1 can modify lung morphogenesis. To examine the effects of antenatal expression of IL-1β in the distal airway epithelium on fetal lung morphogenesis, we studied lung development and surfactant expression in fetal mice expressing human IL-1β under the control of the surfactant protein (SP)-C promoter. IL-1β-expressing pups suffered respiratory failure and died shortly after birth. IL-1β caused fetal lung inflammation and enhanced the expression of keratinocyte-derived chemokine (KC/CXCL1) and monocyte chemoattractant protein 3 (MCP-3/CCL7), the calgranulins S100A8 and S100A9, the acute-phase protein serum amyloid A3 (SAA3), the chitinase-like proteins Ym1 and Ym2, and pendrin. IL-1β decreased the percentage of the total distal lung area made up of air saccules and the number of air saccules in the lungs of fetal mice. IL-1β inhibited the expression of VEGF-A and of its receptors VEGFR-1 and VEGFR-2. The percentage of the cellular area of the distal lung made up of capillaries was decreased in IL-1β-expressing fetal mice. IL-1β suppressed the production of SP-B and pro-SP-C, and decreased the amount of phosphatidylcholine and the percentage of palmitic acid in the phosphatidylcholine fraction of lung phospholipids, indicating that IL-1β prevented the differentiation of type II epithelial cells. The production of Clara cell secretory protein (CCSP) in the nonciliated bronchiolar (Clara) cells was likewise suppressed by IL-1β. In conclusion, expression of IL-1β in the epithelium of the distal airways disrupted the development of the airspaces and capillaries in the fetal lung and caused fatal respiratory failure at birth.
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18.
  • Hogmalm, Anna, 1981, et al. (author)
  • Pulmonary IL-1β expression in early life causes permanent changes in lung structure and function in adulthood.
  • 2018
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 314:6, s. 936-945
  • Journal article (peer-reviewed)abstract
    • Chorioamnionitis, mechanical ventilation, oxygen therapy, and postnatal infection promote inflammation in the newborn lung. The long-term consequences of pulmonary inflammation during infancy have not been well characterized. The aim of this study was to examine the impact of inflammation during the late saccular to alveolar stages of lung development on lung structure and function in adulthood. To induce IL-1β expression in the pulmonary epithelium of mice with a tetracycline-inducible human IL-1β transgene, doxycycline was administered via intraperitoneal injections to bitransgenic pups and their littermate controls on postnatal days (PN) 0, 0.5, and 1. Lung structure, inflammation, and airway reactivity were studied in adulthood. IL-1β production in early life resulted in increased numbers of macrophages and neutrophils on PN21, but inflammation subsided by PN42. Permanent changes in alveolar structure, i. e. larger alveoli and thicker alveolar walls, were present from PN21 to PN84. Lack of alveolar septation thus persisted after IL-1β production and inflammation had ceased. Early IL-1β production caused goblet cell hyperplasia, enhanced calcium-activated chloride channel 3 (CLCA3) protein expression, and increased airway reactivity in response to methacholine on PN42. Lymphoid follicles were present adjacent to small airways in the lungs of adult bitransgenic mice, and levels of the B-cell chemoattractant CXC-motif ligand (CXCL) 13 were elevated in the lungs of bitransgenic mice compared to controls. In conclusion, IL-1β-induced pulmonary inflammation in early life causes a chronic lung disease in adulthood.
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19.
  • Holmén, Jessica, 1971, et al. (author)
  • Mucins and their O-Glycans from human bronchial epithelial cell cultures.
  • 2004
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1040-0605 .- 1522-1504. ; 287:4
  • Journal article (peer-reviewed)abstract
    • A longstanding question in obstructive airway disease is whether observed changes in mucin composition and/or posttranslational glycosylation are due to genetic or to environmental factors. We tested whether the mucins secreted by second-passage primary human bronchial epithelial cell cultures derived from noncystic fibrosis (CF) or CF patients have intrinsically different specific mucin compositions, and whether these mucins are glycosylated differently. Both CF and non-CF cultures produced MUC5B, predominantly, as judged by quantitative agarose gel Western blots with mucin-specific antibodies: MUC5B was present at approximately 10-fold higher levels than MUC5AC, consistent with our previous mRNA studies (Bernacki SH, Nelson AL, Abdullah L, Sheehan JK, Harris A, William DC, and Randell SH. Am J Respir Cell Mol Biol 20: 595-604, 1999). O-linked oligosaccharides released from purified non-CF and CF mucins and studied by HPLC mass spectrometry had highly variable glycan structures, and there were no observable differences between the two groups. Hence, there were no differences in either the specific mucins or their O-glycans that correlated with the CF phenotype under the noninfected/noninflammatory conditions of cell culture. We conclude that the differences observed in the mucins sampled directly from patients are most likely due to environmental factors relating to infection and/or inflammation.
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20.
  • Ikonomou, Laertis, et al. (author)
  • Stem cells, cell therapies, and bioengineering in lung biology and disease 2021
  • 2022
  • In: American Journal of Physiology - Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1040-0605 .- 1522-1504. ; 323:3, s. 341-354
  • Research review (peer-reviewed)abstract
    • The 9th biennial conference titled “Stem Cells, Cell Therapies, and Bioengineering in Lung Biology and Diseases” was hosted virtually, due to the ongoing COVID-19 pandemic, in collaboration with the University of Vermont Larner College of Medicine, the National Heart, Lung, and Blood Institute, the Alpha-1 Foundation, the Cystic Fibrosis Foundation, and the International Society for Cell & Gene Therapy. The event was held from July 12th through 15th, 2021 with a pre-conference workshop held on July 9th. As in previous years, the objectives remained to review and discuss the status of active research areas involving stem cells (SCs), cellular therapeutics, and bioengineering as they relate to the human lung. Topics included 1) technological advancements in the in situ analysis of lung tissues, 2) new insights into stem cell signaling and plasticity in lung remodeling and regeneration, 3) the impact of extracellular matrix in stem cell regulation and airway engineering in lung regeneration, 4) differentiating and delivering stem cell therapeutics to the lung, 5) regeneration in response to viral infection, and 6) ethical development of cell-based treatments for lung diseases. This selection of topics represents some of the most dynamic and current research areas in lung biology.
  •  
21.
  • Johnson, Jill R., et al. (author)
  • Pericytes contribute to airway remodeling in a mouse model of chronic allergic asthma
  • 2015
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 308:7, s. 658-671
  • Journal article (peer-reviewed)abstract
    • Myofibroblast accumulation, subepithelial fibrosis, and vascular remodeling are complicating features of chronic asthma, but the mechanisms are not clear. Platelet-derived growth factors (PDGFs) regulate the fate and function of various mesenchymal cells and have been implicated as mediators of lung fibrosis. However, it is not known whether PDGF-BB signaling via PDGFR beta, which is critical for the recruitment of pericytes to blood vessels, plays a role in airway remodeling in chronic asthma. In the present study, we used a selective PDGFR beta inhibitor (CP-673451) to investigate the role of PDGFR beta signaling in the development of airway remodeling and lung dysfunction in an established mouse model of house dust mite-induced chronic allergic asthma. Unexpectedly, we found that pharmacological inhibition of PDGFR beta signaling in the context of chronic aeroallergen exposure led to exacerbated lung dysfunction and airway smooth muscle thickening. Further studies revealed that the inflammatory response to aeroallergen challenge in mice was associated with decreased PDGF-BB expression and the loss of pericytes from the airway microvasculature. In parallel, cells positive for pericyte markers accumulated in the subepithelial region of chronically inflamed airways. This process was exacerbated in animals treated with CP-673451. The results indicate that perturbed PDGF-BB/PDGFR beta signaling and pericyte accumulation in the airway wall may contribute to airway remodeling in chronic allergic asthma.
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22.
  • Kagan, VE, et al. (author)
  • Appetizing rancidity of apoptotic cells for macrophages: oxidation, externalization, and recognition of phosphatidylserine
  • 2003
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1040-0605 .- 1522-1504. ; 285:1, s. L1-L17
  • Journal article (peer-reviewed)abstract
    • Programmed cell death (apoptosis) functions as a mechanism to eliminate unwanted or irreparably damaged cells ultimately leading to their orderly phagocytosis in the absence of calamitous inflammatory responses. Recent studies have demonstrated that the generation of free radical intermediates and subsequent oxidative stress are implicated as part of the apoptotic execution process. Oxidative stress may simply be an unavoidable yet trivial byproduct of the apoptotic machinery; alternatively, intermediates or products of oxidative stress may act as essential signals for the execution of the apoptotic program. This review is focused on the specific role of oxidative stress in apoptotic signaling, which is realized via phosphatidylserine-dependent pathways leading to recognition of apoptotic cells and their effective clearance. In particular, the mechanisms involved in selective phosphatidylserine oxidation in the plasma membrane during apoptosis and its association with disturbances of phospholipid asymmetry leading to phosphatidylserine externalization and recognition by macrophage receptors are at the center of our discussion. The putative importance of this oxidative phosphatidylserine signaling in lung physiology and disease are also discussed.
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23.
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24.
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25.
  • Larsson, OJ, et al. (author)
  • The TLR7 agonist imiquimod induces bronchodilation via a nonneuronal TLR7-independent mechanism: a possible role for quinoline in airway dilation
  • 2016
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 310:11, s. L1121-L1129
  • Journal article (peer-reviewed)abstract
    • Toll-like receptor (TLR) 7 agonists are known to reduce allergic airway inflammation. Their recently reported ability to rapidly relax airways has further increased their interest in the treatment of pulmonary disease. However, the mechanisms behind this effect are not fully understood. The present study, therefore, aimed to determine whether airway smooth muscle (ASM)-dependent mechanisms could be identified. TLR7 agonists were added to guinea pig airways following precontraction with carbachol in vitro or histamine in vivo. Pharmacological inhibitors were used to dissect conventional pathways of bronchodilation; tetrodotoxin was used or bilateral vagotomy was performed to assess neuronal involvement. Human ASM cells (HASMCs) were employed to determine the effect of TLR7 agonists on intracellular Ca2+([Ca2+]i) mobilization. The well-established TLR7 agonist imiquimod rapidly relaxed precontracted airways in vitro and in vivo. This relaxation was demonstrated to be independent of nitric oxide, carbon monoxide, and cAMP signaling, as well as neuronal activity. A limited role for prostanoids could be detected. Imiquimod induced [Ca2+]irelease from endoplasmic reticulum stores in HASMCs, inhibiting histamine-induced [Ca2+]i. The TLR7 antagonist IRS661 failed to inhibit relaxation, and the structurally dissimilar agonist CL264 did not relax airways or inhibit [Ca2+]i. This study shows that imiquimod acts directly on ASM to induce bronchorelaxation, via a TLR7-independent release of [Ca2+]i. The effect is paralleled by other bronchorelaxant compounds, like chloroquine, which, like imiquimod, but unlike CL264, contains the chemical structure quinoline. Compounds with quinoline moieties may be of interest in the development of multifunctional drugs to treat pulmonary disease.
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26.
  • Li, Zhenjun, et al. (author)
  • Oxidized alpha(1)-antitrypsin stimulates the release of monocyte chemotactic protein-1 from lung epithelial cells: potential role in emphysema
  • 2009
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 297:2, s. 388-400
  • Journal article (peer-reviewed)abstract
    • Li Z, Alam S, Wang J, Sandstrom CS, Janciauskiene S, Mahadeva R. Oxidized alpha(1)-antitrypsin stimulates the release of monocyte chemotactic protein-1 from lung epithelial cells: potential role in emphysema. Am J Physiol Lung Cell Mol Physiol 297: L388-L400, 2009. First published June 12, 2009; doi:10.1152/ajplung.90373.2008.-alpha(1)-Antitrypsin ( AT) is a major elastase inhibitor within the lung. Oxidation of critical methionine residues in AT generates oxidized AT (Ox-AT), which has a greatly diminished ability to inhibit neutrophil elastase. This process may contribute to the pathogenesis of chronic obstructive pulmonary disease (COPD) by creating a functional deficiency of AT permitting lung destruction. We show here that Ox-AT promotes release of human monocyte chemoattractant protein-1 (MCP-1) and IL-8 from human lung type epithelial cells (A549) and normal human bronchial epithelial (NHBE) cells. Native, cleaved, polymeric AT and secretory leukoproteinase inhibitor (SLPI) and oxidized conformations of cleaved, polymeric AT and SLPI did not have any significant effect on MCP-1 and IL-8 secretion. These findings were supported by the fact that instillation of Ox-AT into murine lungs resulted in an increase in JE (mouse MCP-1) and increased macrophage numbers in the bronchoalveolar lavage fluid. The effect of Ox-AT was dependent on NF-kappa B and activator protein-1 (AP-1)/JNK. These findings have important implications. They demonstrate that the oxidation of methionines in AT by oxidants released by cigarette smoke or inflammatory cells not only reduces the antielastase lung protection, but also converts AT into a proinflammatory stimulus. Ox-AT generated in the airway interacts directly with epithelial cells to release chemokines IL-8 and MCP-1, which in turn attracts macrophages and neutrophils into the airways. The release of oxidants by these inflammatory cells could oxidize AT, perpetuating the cycle and potentially contributing to the pathogenesis of COPD. Furthermore, these data demonstrate that molecules such as oxidants, antiproteinases, and chemokines, rather than act independently, are likely to interact to cause emphysema.
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27.
  • Liu, C, et al. (author)
  • 15-Lipoxygenase-1 induces expression and release of chemokines in cultured human lung epithelial cells
  • 2009
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 297:1, s. L196-L203
  • Journal article (peer-reviewed)abstract
    • 15-Lipoxygenase-1 (15-LOX-1) has been proposed to be involved in various physiological and pathophysiological activities such as inflammation, atherosclerosis, cell maturation, and tumorigenesis. Asthma and chronic obstructive pulmonary disease are associated with increased expression of 15-LOX-1 in bronchial epithelial cells, but the potential functions of 15-LOX-1 in airway epithelial cells have not been well clarified. To study the function of 15-LOX-1 in bronchial epithelial cells, we ectopically expressed 15-LOX-1 in the human lung epithelial cell line A549. We found that overexpression of 15-LOX-1 in A549 cells leads to increased release of the chemokines MIP-1α, RANTES, and IP-10, and thereby to increased recruitment of immature dendritic cells, mast cells, and activated T cells. These results suggest that an increased expression and activity of 15-LOX-1 in lung epithelial cells is a proinflammatory event in the pathogenesis of asthma and other inflammatory lung disorders.
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28.
  • Luo, Lingtao, et al. (author)
  • Pro-inflammatory role of neutrophil extracellular traps in abdominal sepsis.
  • 2014
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 307:7, s. 586-596
  • Journal article (peer-reviewed)abstract
    • Excessive neutrophil activation is a major component in septic lung injury. Neutrophil-derived DNA may form extracellular traps in response to bacterial invasions. The aim of the present study was to investigate the potential role of neutrophil extracellular traps (NETs) in septic lung injury. Male C57BL/6 mice were treated with rhDNAse (5 mg/kg) after cecal ligation and puncture (CLP). Extracellular DNA was stained by Sytox green and NET formation was quantified by confocal microscopy and cell-free DNA in plasma, peritoneal cavity and lung. Blood, peritoneal fluid and lung tissue were harvested for analysis of neutrophil infiltration, NET levels, tissue injury as well as CXC chemokine and cytokine formation. We observed that CLP caused increased formation of NETs in the plasma, peritoneal cavity and lung. Administration of rhDNAse not only eliminated NET formation in the plasma, peritoneal cavity and bronchoalveolar space but also reduced lung edema and tissue damage 24 h after CLP induction. Moreover, treatment with rhDNAse decreased CLP-induced formation of CXC chemokines, IL-6 and HMGB1 in the plasma as well as CXC chemokines and IL-6 in the lung. In vitro, we found that neutrophil-derived NETs had the capacity to stimulate secretion of CXCL2, TNF-α and HMGB1 from alveolar macrophages. Taken together, our findings show that NETs regulate pulmonary infiltration of neutrophils and tissue injury via formation of pro-inflammatory compounds in abdominal sepsis. Thus, we conclude that NETs exert a pro-inflammatory role in septic lung injury.
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29.
  • McGovern, TK, et al. (author)
  • Neutrophilic oxidative stress mediates organic dust-induced pulmonary inflammation and airway hyperresponsiveness
  • 2016
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 310:2, s. L155-L165
  • Journal article (peer-reviewed)abstract
    • Airway exposure to organic dust (OD) from swine confinement facilities induces airway inflammation dominated by neutrophils and airway hyperresponsiveness (AHR). One important neutrophilic innate defense mechanism is the induction of oxidative stress. Therefore, we hypothesized that neutrophils exacerbate airway dysfunction following OD exposure by increasing oxidant burden. BALB/C mice were given intranasal challenges with OD or PBS (1/day for 3 days). Mice were untreated or treated with a neutrophil-depleting antibody, anti-Ly6G, or the antioxidant dimethylthiourea (DMTU) prior to OD exposure. Twenty-four hours after the final exposure, we measured airway responsiveness in response to methacholine (MCh) and collected bronchoalveolar lavage fluid to assess pulmonary inflammation and total antioxidant capacity. Lung tissue was harvested to examine the effect of OD-induced antioxidant gene expression and the effect of anti-Ly6G or DMTU. OD exposure induced a dose-dependent increase of airway responsiveness, a neutrophilic pulmonary inflammation, and secretion of keratinocyte cytokine. Depletion of neutrophils reduced OD-induced AHR. DMTU prevented pulmonary inflammation involving macrophages and neutrophils. Neutrophil depletion and DMTU were highly effective in preventing OD-induced AHR affecting large, conducting airways and tissue elastance. OD induced an increase in total antioxidant capacity and mRNA levels of NRF-2-dependent antioxidant genes, effects that are prevented by administration of DMTU and neutrophil depletion. We conclude that an increase in oxidative stress and neutrophilia is critical in the induction of OD-induced AHR. Prevention of oxidative stress diminishes neutrophil influx and AHR, suggesting that mechanisms driving OD-induced AHR may be dependent on neutrophil-mediated oxidant pathways.
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30.
  • McGovern, T, et al. (author)
  • Organic dust, causing both oxidative stress and Nrf2 activation, is phagocytized by bronchial epithelial cells
  • 2019
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 317:3, s. L305-L316
  • Journal article (peer-reviewed)abstract
    • Inhalation of organic dust (OD) from swine confinement facilities leads to pulmonary inflammation, airway hyperresponsiveness, and oxidative stress. In mice, pretreatment with a hydroxyl radical scavenger prevents airway inflammation and airway hyperresponsiveness (AHR) induced by OD exposure. We sought to determine a mechanism by which OD could induce oxidative stress in bronchial epithelial cells. Human bronchial epithelial cells (BEAS-2B or NHBE) were treated with various concentrations of OD, followed by evaluation of intracellular oxidative stress using 2′,7′–dichlorofluorescein diacetate (DCFDA). After stimulation with OD, gene expression of antioxidant genes was assessed by real-time quantitative PCR followed by quantification of Nrf2 nuclear translocation using a luciferase reporter assay. Phagocytic markers (CD36 and CD68) were analyzed by FACS. Cells were treated with an actin inhibitor, cytochalasin D, before OD exposure and evaluated for Nrf2 nuclear translocation and DCFDA. Mice were pretreated with sulforaphane, the Nrf2 activator, before OD exposure and evaluated for pulmonary inflammation and airway reactivity. OD induced a time- and concentration-dependent increase in DCFDA. mRNA expression levels of Nrf2-dependent genes and Nrf2 nuclear translocation were increased after OD exposure. OD exposure increased the expression of CD68 and CD36. Cytochalasin D prevented oxidative stress and Nrf2 nuclear translocation after OD. Pretreatment with sulforaphane prevented OD-induced inflammation and AHR while increasing the uptake of OD in bronchial epithelial cells. Bronchial epithelial cells can phagocytose OD, resulting in an increase in endogenous oxidative stress. Nrf2-dependent mechanisms mediate the antioxidant response to OD.
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31.
  • Nguyen, Tram Mai, et al. (author)
  • Stretch increases alveolar type 1 cell number in fetal lungs through ROCK-Yap/Taz pathway
  • 2021
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 321:5, s. 814-826
  • Journal article (peer-reviewed)abstract
    • Accurate fluid pressure in the fetal lung is critical for its development, especially at the beginning of the saccular stage when alveolar epithelial type 1 (AT1) and type 2 (AT2) cells differentiate from the epithelial progenitors. Despite our growing understanding of the role of physical forces in lung development, the molecular mechanisms that regulate the transduction of mechanical stretch to alveolar differentiation remain elusive. To simulate lung distension, we optimized both an ex vivo model with precision cut lung slices and an in vivo model of fetal tracheal occlusion. Increased mechanical tension showed to improve alveolar maturation and differentiation toward AT1. By manipulating ROCK pathway, we demonstrate that stretch-induced Yap/Taz activation promotes alveolar differentiation toward AT1 phenotype via ROCK activity. Our findings show that balanced ROCK-Yap/Taz signaling is essential to regulate AT1 differentiation in response to mechanical stretching of the fetal lung, which might be helpful in improving lung development and regeneration.
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32.
  • Norlin, Andreas, et al. (author)
  • Ca(2+)-dependent stimulation of alveolar fluid clearance in near-term fetal guinea pigs.
  • 2002
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 282:4, s. 642-649
  • Journal article (peer-reviewed)abstract
    • We investigated the importance of changes in intracellular Ca(2+) concentration ([Ca(2+)](i)) for amiloride-sensitive alveolar fluid clearance (AFC) in late-gestational guinea pigs. Fetal guinea pigs of 61, 68, and 69 days (term) gestation were investigated under normal conditions and after oxytocin-induced preterm labor. AFC or alveolar fluid secretion was measured using an impermeable tracer technique. At 61 days gestation there was net secretion of fluid into the lungs, and at birth the lungs cleared 49 plus minus 7% of the instilled fluid volume over 1 h. Induction of preterm labor with oxytocin induced AFC at 61 days gestation. When present, AFC was inhibited or reversed to net fluid secretion by amiloride (10(minus sign3) M). Inhibition of membrane Ca(2+) channels by verapamil (10(minus sign4) M) or depletion of intracellular Ca(2+) by thapsigargin (10(minus sign5) M) reduced AFC when net AFC was evident. Amiloride lacked an inhibitory effect on AFC when instilled with verapamil or thapsigargin. The results indicate that AFC via amiloride-sensitive pathways develops during late gestation, and that inducing preterm labor precociously may activate such pathways. Our results suggest that Ca(2+) may act as a second messenger in mediating catecholamine-stimulated AFC.
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33.
  • Norvik, Christian, et al. (author)
  • Synchrotron-based phase-contrast micro-CT as a tool for understanding pulmonary vascular pathobiology and the 3-D microanatomy of alveolar capillary dysplasia
  • 2020
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 318:1, s. 65-75
  • Journal article (peer-reviewed)abstract
    • This study aimed to explore the value of synchrotron-based phase-contrast microcomputed tomography (micro-CT) in pulmonary vascular pathobiology. The microanatomy of the lung is complex with intricate branching patterns. Tissue sections are therefore difficult to interpret. Recruited intrapulmonary bronchopulmonary anastomoses (IBAs) have been described in several forms of pulmonary hypertension, including alveolar capillary dysplasia with misaligned pulmonary veins (ACD/MPV). Here, we examine paraffin-embedded tissue using this nondestructive method for high-resolution three-dimensional imaging. Blocks of healthy and ACD/MPV lung tissue were used. Pulmonary and bronchial arteries in the ACD/MPV block had been preinjected with dye. One section per block was stained, and areas of interest were marked to allow precise beam-alignment during image acquisition at the X02DA TOMCAT beamline (Swiss Light Source). A ×4 magnifying objective coupled to a 20-µm thick scintillating material and a sCMOS detector yielded the best trade-off between spatial resolution and field-of-view. A phase retrieval algorithm was applied and virtual tomographic slices and video clips of the imaged volumes were produced. Dye injections generated a distinct attenuation difference between vessels and surrounding tissue, facilitating segmentation and three-dimensional rendering. Histology and immunohistochemistry post-imaging offered complementary information. IBAs were confirmed in ACD/MPV, and the MPVs were positioned like bronchial veins/venules. We demonstrate the advantages of using synchrotron-based phase-contrast micro-CT for three-dimensional characterization of pulmonary microvascular anatomy in paraffin-embedded tissue. Vascular dye injections add additional value. We confirm intrapulmonary shunting in ACD/MPV and provide support for the hypothesis that MPVs are dilated bronchial veins/venules.
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34.
  • Park, Juwon, et al. (author)
  • The Tcf21 lineage constitutes the lung lipofibroblast population
  • 2019
  • In: American Journal of Physiology - Lung cellular and Molecular Physiology. - : AMER PHYSIOLOGICAL SOC. - 1040-0605 .- 1522-1504. ; 316:5, s. L872-L885
  • Journal article (peer-reviewed)abstract
    • Transcription factor 21 (Tcf21) is a basic helix-loop-helix transcription factor required for mesenchymal development in several organs. Others have demonstrated that Tcf21 is expressed in embryonic lung mesenchyme and that loss of Tcf21 results in a pulmonary hypoplasia phenotype. Although recent single-cell transcriptome analysis has described multiple mesenchymal cell types in the lung, few have characterized the Tcf21 expressing population. To explore the Tcf21 mesenchymal lineage, we traced Tcf21-expressing cells during embryogenesis and in the adult. Our results showed that Tcf21 progenitor cells at embryonic day (E) 11.5 generated a subpopulation of fibroblasts and lipofibroblasts and a limited number of smooth muscle cells. After E15.5, Tcf21 progenitor cells exclusively become lipofibroblasts and interstitial fibroblasts. Lipid metabolism genes were highly expressed in perinatal and adult Tcf21 lineage cells. Overexpression of Tcf21 in primary neonatal lung fibroblasts led to increases in intracellular neutral lipids, suggesting a regulatory role for Tcf21 in lipofibroblast function. Collectively, our results reveal that Tcf21 expression after E15.5 delineates the lipofibroblast and a population of interstitial fibroblasts. The Tcf21 inducible Cre mouse line provides a novel method for identifying and manipulating the lipofibroblast.
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35.
  • Pourazar, Jamshid, et al. (author)
  • Diesel exhaust activates redox-sensitive transcription factors and kinases in human airways
  • 2005
  • In: American Journal of Physiology - Lung cellular and Molecular Physiology. - : American Physiological Society. - 1040-0605 .- 1522-1504. ; 289:5, s. L724-L730
  • Journal article (peer-reviewed)abstract
    • Diesel exhaust (DE) is a major component of airborne particulate matter. In previous studies we have described the acute inflammatory response of the human airway to inhaled DE. This was characterized by neutrophil, mast cell, and lymphocyte infiltration into the bronchial mucosa with enhanced epithelial expression of IL-8, Gro-alpha, and IL-13. In the present study, we investigated whether redox-sensitive transcription factors were activated as a consequence of DE exposure, consistent with oxidative stress triggering airway inflammation. In archived biopsies from 15 healthy subjects exposed to DE [particulates with a mass median diameter of <10 mum, 300 microg/m3] and air, immunohistochemical staining was used to quantify the expression of the transcription factors NF-kappaB (p65) and AP-1 (c-jun and c-fos), as well their upstream MAPKs, p38 and JNK, in the bronchial epithelium. In addition, phosphorylation of tyrosine residues was examined. DE induced a significant increase in the nuclear translocation of NF-kappaB (P = 0.02), AP-1 (P = 0.02), phosphorylated JNK (P = 0.04), and phosphorylated p38 (P = 0.01), as well as an increase in total (cytoplasmic + nuclear) immunostaining of phosphorylated p38 (P = 0.03). A significant increase in nuclear phosphorylated tyrosine was also observed (P < 0.05). These observations demonstrate that DE activates redox-sensitive transcription factors in vivo consistent with oxidative stress triggering the increased synthesis of proinflammatory cytokines.
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36.
  • Pulkkinen, V, et al. (author)
  • The bitter taste receptor (TAS2R) agonists denatonium and chloroquine display distinct patterns of relaxation of the guinea pig trachea
  • 2012
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 303:11, s. L956-L966
  • Journal article (peer-reviewed)abstract
    • Activation of taste receptors (TAS2Rs) by bitter taste agonists has been reported to cause bronchodilation. The aim of this study was to extend the information on the effects of bitter taste agonists on responses induced by different contractile mediators in a standard airway physiology preparation. Isometric responses were assessed in guinea pig trachea (GPT). TAS2R agonists were administered either to segments precontracted with different agonists for contraction or given before challenge with the different contractile stimuli, including antigen in tissues from ovalbumin-sensitized animals. TAS2R mRNA expression on GPT epithelium and smooth muscle was measured with real-time PCR. Denatonium, chloroquine, thiamine, and noscapine induced concentration-dependent relaxations (Rmax: 98.3 ± 1.6, 100.0 ± 0.0, 100.0 ± 0.0, and 52.3 ± 1.1% of maximum, respectively, in the presence of indomethacin) in segments precontracted with carbachol. The receptors for denatonium (TAS2R4, TAS2R10) and chloroquine (TAS2R3, TAS2R10) were expressed in GPT. Whereas denatonium selectively inhibited contractions induced by carbachol, chloroquine uniformly inhibited contractions evoked by prostaglandin E2, the thromboxane receptor agonist U-46619, leukotriene D4, histamine, and antigen. The effects of denatonium, but not those of chloroquine, were partly inhibited by blockers of the large Ca2+-activated K+ channels and decreased by an increase of the level of precontraction. In conclusion, TAS2R agonists mediated strong relaxations and substantial inhibition of contractions in GPT. Chloroquine and denatonium had distinct patterns of activity, indicating different signaling mechanisms. The findings reinforce the hypothesis that TAS2Rs are potential targets for the development of a new class of more efficacious agonists for bronchodilation.
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37.
  • Rentsendorj, O, et al. (author)
  • Role of vasodilator-stimulated phosphoprotein in cGMP-mediated protection of human pulmonary artery endothelial barrier function
  • 2008
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1040-0605 .- 1522-1504. ; 294:4, s. L686-L697
  • Journal article (peer-reviewed)abstract
    • Increased pulmonary endothelial cGMP was shown to prevent endothelial barrier dysfunction through activation of protein kinase G (PKGI). Vasodilator-stimulated phosphoprotein (VASP) has been hypothesized to mediate PKGIbarrier protection because VASP is a cytoskeletal phosphorylation target of PKGIexpressed in cell-cell junctions. Unphosphorylated VASP was proposed to increase paracellular permeability through actin polymerization and stress fiber bundling, a process inhibited by PKGI-mediated phosphorylation of Ser157and Ser239. To test this hypothesis, we examined the role of VASP in the transient barrier dysfunction caused by H2O2in human pulmonary artery endothelial cell (HPAEC) monolayers studied without and with PKGIexpression introduced by adenoviral infection (Ad.PKG). In the absence of PKGIexpression, H2O2(100–250 μM) caused a transient increased permeability and pSer157-VASP formation that were both attenuated by protein kinase C inhibition. Potentiation of VASP Ser157phosphorylation by either phosphatase 2B inhibition with cyclosporin or protein kinase A activation with forskolin prolonged, rather than inhibited, the increased permeability caused by H2O2. With Ad.PKG infection, inhibition of VASP expression with small interfering RNA exacerbated H2O2-induced barrier dysfunction but had no effect on cGMP-mediated barrier protection. In addition, expression of a Ser-double phosphomimetic mutant VASP failed to reproduce the protective effects of activated PKGI. Finally, expression of a Ser-double phosphorylation-resistant VASP failed to interfere with the ability of cGMP/PKGIto attenuate H2O2-induced disruption of VE-cadherin homotypic binding. Our results suggest that VASP phosphorylation does not explain the protective effect of cGMP/PKGIon H2O2-induced endothelial barrier dysfunction in HPAEC.
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38.
  • Stegmayr, John, et al. (author)
  • Isolation of high yield and quality RNA from human precision-cut lung slices for RNA-sequencing and computational integration with larger patient cohorts
  • 2021
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 320:2, s. 232-240
  • Journal article (peer-reviewed)abstract
    • Precision-cut lung slices (PCLS) have gained increasing interest as a model to study lung biology/disease and screening novel therapeutics. In particular, PCLS derived from human tissue can better recapitulate some aspects of lung biology/disease as compared to animal models. Several experimental readouts have been established for use with PCLS, but obtaining high yield and quality RNA for downstream analysis has remained challenging. This is particularly problematic for utilizing the power of next-generation sequencing techniques, such as RNA-sequencing (RNA-seq), for non-biased and high through-put analysis of PCLS human cohorts. In the current study, we present a novel approach for isolating high quality RNA from a small amount of tissue, including diseased human tissue, such as idiopathic pulmonary fibrosis (IPF). We show that the RNA isolated using this method has sufficient quality for RT-qPCR and RNA-seq analysis. Furthermore, the RNA-seq data from human PCLS could be used in several established computational pipelines, including deconvolution of bulk RNA-seq data using publicly available single-cell RNA-seq data. Deconvolution using Bisque revealed a diversity of cell populations in human PCLS, including several immune cell populations, which correlated with cell populations known to be present and aberrant in human disease.
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39.
  • Stenlo, Martin, et al. (author)
  • Increased particle flow rate from airways precedes clinical signs of ARDS in a porcine model of LPS-induced acute lung injury
  • 2020
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 318:3, s. 510-517
  • Journal article (peer-reviewed)abstract
    • Acute respiratory distress syndrome (ARDS) is a common cause of death in the intensive care unit, with mortality rates of ~30-40%. To reduce invasive diagnostics such as bronchoalveolar lavage and time-consuming in-hospital transports for imaging diagnostics, we hypothesized that particle flow rate (PFR) pattern from the airways could be an early detection method and contribute to improving diagnostics and optimizing personalized therapies. Porcine models were ventilated mechanically. Lipopolysaccharide (LPS) was administered endotracheally and in the pulmonary artery to induce ARDS. PFR was measured using a customized particles in exhaled air (PExA 2.0) device. In contrast to control animals undergoing mechanical ventilation and receiving saline administration, animals who received LPS developed ARDS according to clinical guidelines and histologic assessment. Plasma levels of TNF-α and IL-6 increased significantly compared with baseline after 120 and 180 min, respectively. On the other hand, the PFR significantly increased and peaked 60 min after LPS administration, i.e., ~30 min before any ARDS stage was observed with other well-established outcome measurements such as hypoxemia, increased inspiratory pressure, and lower tidal volumes or plasma cytokine levels. The present results imply that PFR could be used to detect early biomarkers or as a clinical indicator for the onset of ARDS.
  •  
40.
  • Tannenberg, Philip, et al. (author)
  • Extracellular retention of PDGF-B directs vascular remodeling in mouse hypoxia-induced pulmonary hypertension
  • 2018
  • In: American Journal of Physiology - Lung cellular and Molecular Physiology. - : AMER PHYSIOLOGICAL SOC. - 1040-0605 .- 1522-1504. ; 314:4, s. 1593-1605
  • Journal article (peer-reviewed)abstract
    • Pulmonary hypertension (PH) is a lethal condition, and current vasodilator therapy has limited effect. Antiproliferative strategies targeting platelet-derived growth factor (PDGF) receptors, such as imatinib, have generated promising results in animal studies. Imatinib is, however, a nonspecific tyrosine kinase inhibitor and has in clinical studies caused unacceptable adverse events. Further studies are needed on the role of PDGF signaling in PH. Here, mice expressing a variant of PDGF-B with no retention motif (Pdgfb(ret/ret)), resulting in defective binding to extracellular matrix, were studied. Following 4 wk of hypoxia, right ventricular systolic pressure, right ventricular hypertrophy, and vascular remodeling were examined. Pdgfb(ret/ret) mice did not develop PH, as assessed by hemodynamic parameters. Hypoxia did, however, induce vascular remodeling in Pdgfb(ret/ret) mice; but unlike the situation in controls where the remodeling led to an increased concentric muscularization of arteries, the vascular remodeling in Pdgfb(ret/ret) mice was characterized by a diffuse muscularization, in which cells expressing smooth muscle cell markers were found in the interalveolar septa detached from the normally muscularized intra-acinar vessels. Additionally, fewer NG2-positive perivascular cells were found in Pdgfb(ret/ret) lungs, and mRNA analyses showed significantly increased levels of Il6 following hypoxia, a known promigratory factor for pericytes. No differences in proliferation were detected at 4 wk. This study emphasizes the importance of extracellular matrix-growth factor interactions and adds to previous knowledge of PDGF-B in PH pathobiology. In summary, Pdgfb(ret/ret) mice have unaltered hemodynamic parameters following chronic hypoxia, possibly secondary to a disorganized vascular muscularization.
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41.
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42.
  • Togo, S, et al. (author)
  • PDE4 inhibitors roflumilast and rolipram augment PGE2 inhibition of TGF-{beta}1-stimulated fibroblasts
  • 2009
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1040-0605 .- 1522-1504. ; 296:6, s. L959-L969
  • Journal article (peer-reviewed)abstract
    • Fibrotic diseases are characterized by the accumulation of extracellular matrix together with distortion and disruption of tissue architecture. Phosphodiesterase (PDE)4 inhibitors, by preventing the breakdown of cAMP, can inhibit fibroblast functions and may be able to mitigate tissue remodeling. Transforming growth factor (TGF)-β1, a mediator of fibrosis, can potentially modulate cAMP by altering PGE2 metabolism. The present study assessed whether PDE4 inhibitors functionally antagonize the profibrotic activity of fibroblasts stimulated by TGF-β1. The PDE4 inhibitors roflumilast and rolipram both inhibited fibroblast-mediated contraction of three-dimensional collagen gels and fibroblast chemotaxis toward fibronectin in the widely studied human fetal lung fibroblast strain HFL-1 and several strains of fibroblasts from adult human lung. Roflumilast was ∼10-fold more potent than rolipram. There was a trend for PDE4 inhibitors to inhibit more in the presence of TGF-β1 (0.05 < P < 0.08). The effect of the PDE4 inhibitors was mediated through cAMP-stimulated protein kinase A (PKA), although a PKA-independent effect on gel contraction was also observed. The effect of PDE4 inhibitors depended on fibroblast production of PGE2 and TGF-β1-induced PGE2 production. PDE4 inhibitors together with TGF-β1 resulted in augmented PGE2 production together with increased expression of COX mRNA and protein. The present study supports the concept that PDE4 inhibitors may attenuate fibroblast activities that can lead to fibrosis and that PDE4 inhibitors may be particularly effective in the presence of TGF-β1-induced fibroblast stimulation.
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43.
  • van der Velden, Jos L., et al. (author)
  • TGF-β1-induced deposition of provisional extracellular matrix by tracheal basal cells promotes epithelial-to-mesenchymal transition in a c-Jun NH2-terminal kinase-1-dependent manner
  • 2018
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 314:6, s. 984-997
  • Journal article (peer-reviewed)abstract
    • Epithelial cells have been suggested as potential drivers of lung fibrosis, although the epithelial-dependent pathways that promote fibrogenesis remain unknown. Extracellular matrix is increasingly recognized as an environment that can drive cellular responses in various pulmonary diseases. In this study, we demonstrate that transforming growth factor-β1 (TGF-β1)-stimulated mouse tracheal basal (MTB) cells produce provisional matrix proteins in vitro, which initiate mesenchymal changes in subsequently freshly plated MTB cells via Rho kinase-and c-Jun NH2-terminal kinase (JNK1)-dependent processes. Repopulation of decellularized lung scaffolds, derived from mice with bleomycin-induced fibrosis or from patients with idiopathic pulmonary fibrosis, with wild-type MTB cells resulted in a loss of epithelial gene expression and augmentation of mesenchymal gene expression compared with cells seeded into decellularized normal lungs. In contrast, Jnk1-/- basal cells seeded into fibrotic lung scaffolds retained a robust epithelial expression profile, failed to induce mesenchymal genes, and differentiated into club cell secretory protein-expressing cells. This new paradigm wherein TGF-β1-induced extracellular matrix derived from MTB cells activates a JNK1-dependent mesenchymal program, which impedes subsequent normal epithelial cell homeostasis, provides a plausible scenario of chronic aberrant epithelial repair, thought to be critical in lung fibrogenesis. This study identifies JNK1 as a possible target for inhibition in settings wherein reepithelialization is desired.
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44.
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45.
  • Wang, Yongzhi, et al. (author)
  • Distinct patterns of leukocyte recruitment in the pulmonary microvasculature in response to local and systemic inflammation
  • 2013
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 304:4, s. 298-305
  • Journal article (peer-reviewed)abstract
    • Wang Y, Roller J, Slotta JE, Zhang S, Luo L, Rahman M, Syk I, Menger MD, Thorlacius H. Distinct patterns of leukocyte recruitment in the pulmonary microvasculature in response to local and systemic inflammation. Am J Physiol Lung Cell Mol Physiol 304: L298-L305, 2013. First published December 28, 2012; doi:10.1152/ajplung.00246.2012.The mechanisms of leukocyte recruitment in the pulmonary microvasculature in response to local and systemic inflammation remain elusive. Male C57BL/6 mice received lipopolysaccharide (LPS) intrapulmonary (intratracheally, it) or systemically (intravenously, iv) for 1-18 h. Leukocyte responses in lung were analyzed by use of intravital fluorescence microscopy. Plasma and lung levels of CXC chemokines as well as Mac-1 and F-actin expression in leukocytes and bronchoalveolar leukocytes were quantified. Venular leukocyte rolling was markedly increased in response to local LPS but only marginally after systemic LPS. Leukocyte adhesion in venules was enhanced in both groups although adhesion was higher in mice receiving LPS intratracheally compared with LPS intravenously. Systemic LPS caused more leukocytes trapping in capillaries compared with local LPS. The ratio of adherent leukocytes in venules compared with capillaries was higher in response to local LPS, suggesting that leukocytes were more prone to accumulate in venules in local inflammation and in capillaries in systemic inflammation. Systemic LPS triggered higher F-actin formation and Mac-1 expression in leukocytes compared with local LPS. Local and systemic LPS caused similar increases in CXC chemokines in the lung whereas intravenous endotoxin provoked higher levels of CXC chemokines in the circulation. Interestingly, intratracheal LPS increased recruitment of leukocytes in the alveolar space whereas intravenous LPS was ineffective in promoting leukocyte accumulation in the bronchoalveolar space. In conclusion, our data demonstrate that pulmonary microvascular recruitment of leukocytes differs in local and systemic inflammation, which might be related to premature activation and stiffening of circulating leukocytes in endotoxemia.
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46.
  • Xu, Y, et al. (author)
  • Long-term nicotine exposure dampens LPS-induced nerve-mediated airway hyperreactivity in murine airways
  • 2017
  • In: American journal of physiology. Lung cellular and molecular physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 313:3, s. L516-L523
  • Journal article (peer-reviewed)abstract
    • Nicotine is a major component of cigarette smoke. It causes addiction and is used clinically to aid smoke cessation. The aim of the present study is to investigate the effect of nicotine on lipopolysaccharide (LPS)-induced airway hyperreactivity (AHR) and to explore the potential involvement of neuronal mechanisms behind nicotine’s effects in murine models in vivo and in vitro. BALB/c mice were exposed to nicotine in vivo via subcutaneous Alzet osmotic minipumps containing nicotine tartate salt solution (24 mg·kg−1·day−1) for 28 days. LPS (0.1 mg/ml, 20 µl) was administered intranasally for 3 consecutive days during the end of this period. Lung functions were measured with flexiVent. For the in vitro experiments, mice tracheae were organcultured with either nicotine (10 μM) or vehicle (DMSO, 0.1%) for 4 days. Contractile responses of the tracheal segments were measured in myographs following electric field stimulation (EFS; increasing frequencies of 0.2 to 12.8 Hz) before and after incubation with 10 µg/ml LPS for 1 h. Results showed that LPS induced AHR to methacholine in vivo and increased contractile responses to EFS in vitro. Interestingly, long-term nicotine exposure markedly dampened this LPS-induced AHR both in vitro and in vivo. Tetrodotoxin (TTX) inhibited LPS-induced AHR but did not further inhibit nicotine-suppressed AHR in vivo. In conclusion, long-term nicotine exposure dampened LPS-induced AHR. The effect of nicotine was mimicked by TTX, suggesting the involvement of neuronal mechanisms. This information might be used for evaluating the long-term effects of nicotine and further exploring of how tobacco products interact with bacterial airway infections.
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47.
  • Zhang, Songen, et al. (author)
  • Simvastatin regulates CXC chemokine formation in streptococcal M1 protein-induced neutrophil infiltration in the lung
  • 2011
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 300:6, s. 930-939
  • Journal article (peer-reviewed)abstract
    • Zhang S, Rahman M, Zhang S, Qi Z, Herwald H, Thorlacius H. Simvastatin regulates CXC chemokine formation in streptococcal M1 protein-induced neutrophil infiltration in the lung. Am J Physiol Lung Cell Mol Physiol 300: L930-L939, 2011. First published March 25, 2011; doi:10.1152/ajplung.00422.2010.-Streptococcus pyogenes of the M1 serotype can cause streptococcal toxic shock syndrome and acute lung injury. Statins exert beneficial effects in septic patients although the mechanisms remain elusive. This study examined effects of simvastatin on M1 protein-provoked pulmonary inflammation and tissue injury. Male C57BL/6 mice were pretreated with simvastatin or a CXCR2 antagonist before M1 protein challenge. Bronchoalveolar fluid and lung tissue were harvested for determination of neutrophil infiltration, formation of edema, and CXC chemokines. Flow cytometry was used to determine Mac-1 expression on neutrophils. Gene expression of CXC chemokines was determined in alveolar macrophages by using quantitative RT-PCR. M1 protein challenge caused massive infiltration of neutrophils, edema formation, and production of CXC chemokines in the lung as well as upregulation of Mac-1 on circulating neutrophils. Simvastatin reduced M1 protein-induced infiltration of neutrophils and edema in the lung. In addition, M1 protein-induced Mac-1 expression on neutrophils was abolished by simvastatin. Furthermore, simvastatin markedly decreased pulmonary formation of CXC chemokines and gene expression of CXC chemokines in alveolar macrophages. Moreover, the CXCR2 antagonist reduced M1 protein-induced neutrophil expression of Mac-1 and accumulation of neutrophils as well as edema formation in the lung. These novel findings indicate that simvastatin is a powerful inhibitor of neutrophil infiltration in acute lung damage triggered by streptococcal M1 protein. The inhibitory effect of simvastatin on M1 protein-induced neutrophil recruitment appears related to reduced pulmonary generation of CXC chemokines. Thus, simvastatin may be a useful tool to ameliorate acute lung injury in streptococcal infections.
  •  
48.
  • Zhang, Songen, et al. (author)
  • STAT3-dependent CXC chemokine formation and neutrophil migration in Streptococcal M1 protein-induced acute lung inflammation.
  • 2015
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 308:11, s. 1159-1167
  • Journal article (peer-reviewed)abstract
    • Streptococcus pyogenes cause infections ranging from mild pharyngitis to severe streptococcal toxic shock syndrome (STSS). The M1 serotype of Streptococcus pyogenes is most frequently associated with STSS. Herein, it was hypothesized that STAT3 signaling might be involved in M1 protein-evoked lung inflammation. The STAT3 inhibitor, S3I-201, was administered to male C57Bl/6 mice before i.v. challenge with M1 protein. Bronchoalveolar fluid and lung tissue were harvested for quantification of STAT3 activity, neutrophil recruitment, edema and CXC chemokine formation. Neutrophil expression of Mac-1 was quantified by use of flow cytometry. Levels of IL-6 and HMGB1 were determined in plasma. CXCL2-induced neutrophil chemotaxis was studied in vitro. Administration of S3I-201 markedly reduced M1 protein-provoked STAT3 activity, neutrophil recruitment, edema formation and inflammatory changes in the lung. In addition, M1 protein significantly increased Mac-1 expression on neutrophils and CXC chemokine levels in the lung. Treatment with S3I-201 had no effect on M1 protein-induced expression of Mac-1 on neutrophils. In contrast, inhibition of STAT3 activity greatly reduced M1 protein-induced formation of CXC chemokines in the lung. Interestingly, STAT3 inhibition markedly decreased plasma levels of IL-6 and HMGB1 in animals exposed to M1 protein. Moreover, we found that S3I-201 abolished CXCL2-induced neutrophil migration in vitro. In conclusion, these novel findings indicate that STAT3 signaling plays a key role in mediating CXC chemokine production and neutrophil infiltration in M1 protein-induced acute lung inflammation.
  •  
49.
  • Zhang, Songen, et al. (author)
  • Targeting CD162 protects against streptococcal M1 protein-evoked neutrophil recruitment and lung injury
  • 2013
  • In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 305:10, s. 756-763
  • Journal article (peer-reviewed)abstract
    • Streptococcus pyogenes of the M1 serotype can cause streptococcal toxic shock syndrome and acute lung damage. CD162 is an adhesion molecule that has been reported to mediate neutrophil recruitment in acute inflammatory reactions. In this study, the purpose was to investigate the role of CD162 in M1 protein-provoked lung injury. Male C57BL/6 mice were treated with monoclonal antibody directed against CD162 or a control antibody before M1 protein challenge. Edema, neutrophil infiltration, and CXC chemokines were determined in the lung, 4 h after M1 protein administration. Fluorescence intravital microscopy was used to analyze leukocyte-endothelium interactions in the pulmonary microcirculation. Inhibition of CD162 reduced M1 protein-provoked accumulation of neutrophils, edema, and CXC chemokine formation in the lung by >54%. Moreover, immunoneutralization of CD162 abolished leukocyte rolling and firm adhesion in pulmonary venules of M1 protein-treated animals. In addition, inhibition of CD162 decreased M1 protein-induced capillary trapping of leukocytes in the lung microvasculature and improved microvascular perfusion in the lungs of M1 protein-treated animals. Our findings suggest that CD162 plays an important role in M1 protein-induced lung damage by regulating leukocyte rolling in pulmonary venules. Consequently, inhibition of CD162 attenuates M1 protein-evoked leukocyte adhesion and extravasation in the lung. Thus, our results suggest that targeting the CD162 might pave the way for novel opportunities to protect against pulmonary damage in streptococcal infections.
  •  
50.
  • Zhong, Y., et al. (author)
  • IL-1 beta dysregulates cGMP signaling in the newborn lung
  • 2020
  • In: American Journal of Physiology-Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1040-0605 .- 1522-1504. ; 319:1
  • Journal article (peer-reviewed)abstract
    • Cyclic guanosine monophosphate (cGMP) signaling is an important regulator of newborn lung function and development. Although cGMP signaling is decreased in many models of newborn lung injury, the mechanisms are poorly understood. We determined how IL-1 beta regulates the expression of the alpha 1-subunit of soluble guanylate cyclase (sGC alpha 1), a prime effector of pulmonary cGMP signaling. Physiologic levels of IL-1 beta were discovered to rapidly decrease sGC alpha 1 mRNA expression in a human fetal lung fibroblast cell line (IMR-90 cells) and protein levels in primary mouse pup lung fibroblasts. This sGC alpha 1 expression inhibition appeared to be at a transcriptional level; IL-1 beta treatment did not alter sGC alpha 1 mRNA stability, although it reduced sGC alpha 1 promoter activity. Transforming growth factor-beta (TGF beta)-activated kinase-1 (TAK1) was determined to be required for IL-1 beta's regulation of sGC alpha 1 expression; TAK1 knockdown protected sGC alpha 1mRNA expression in IL-1 beta-treated IMR-90 cells. Moreover. heterologously expressed TAK1 was sufficient to decrease sGC alpha 1 mRNA levels in those cells. Nuclear factor-kappa B (NF-kappa B) signaling played a critical role in the IL-1 beta-TAK1-sGC alpha 1 regulatory pathway; chromatin immunoprecipitation studies demonstrated enhanced activated NF-kappa B subunit (RelA) binding to the sGC alpha 1 promoter after IL-1 beta treatment unless treated with an I kappa B kinase-2 inhibitor. Also, this NF-kappa B signaling inhibition protected sGC alpha 1 expression in IL-1 beta-treated fibroblasts. Lastly, using transgenic mice in which active IL-1 beta was conditionally expressed in lung epithelial cells, we established that IL-1 beta expression is sufficient to stimulate TAK1 and decrease sGC alpha 1 protein expression in the newborn lung. Together these results detail the role and mechanisms by which IL-1 beta inhibits cGMP signaling in the newborn lung.
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