CXCR2 is essential for maximal neutrophil recruitment and methacholine responsiveness after ozone exposure

2005 ◽  
Vol 288 (1) ◽  
pp. L61-L67 ◽  
Author(s):  
Richard A. Johnston ◽  
Joseph P. Mizgerd ◽  
Stephanie A. Shore
Keyword(s):  
Epithelial Cell ◽  
Lavage Fluid ◽  
Air Pollutant ◽  
Neutrophil Recruitment ◽  
Ozone Exposure ◽  
Whole Body ◽  
Wild Type ◽  
Protein Levels ◽  
Indirect Measures ◽  
Deficient Mice

Ozone (O3), a common air pollutant, induces airway inflammation and airway hyperresponsiveness. In mice, the neutrophil chemokines KC and macrophage inflammatory protein-2 (MIP-2) are expressed in the lungs following O3 exposure. The purpose of this study was to determine whether CXCR2, the receptor for these chemokines, is essential to O3-induced neutrophil recruitment, injury to lungs, and increases in respiratory system responsiveness to methacholine (MCh). O3 exposure (1 ppm for 3 h) increased the number of neutrophils in the bronchoalveolar lavage fluid (BALF) of wild-type (BALB/c) and CXCR2-deficient mice. However, CXCR2-deficient mice had significantly fewer emigrated neutrophils than did wild-type mice. The numbers of neutrophils in the blood and concentrations of BALF KC and MIP-2 did not differ between genotypes. Together, these data suggest CXCR2 is essential for maximal chemokine-directed migration of neutrophils to the air spaces. In wild-type mice, O3 exposure increased BALF epithelial cell numbers and total protein levels, two indirect measures of lung injury. In contrast, in CXCR2-deficient mice, the number of BALF epithelial cells was not increased by O3 exposure. Responses to inhaled MCh were measured by whole body plethysmography using enhanced pause as the outcome indicator. O3 exposure increased responses to inhaled MCh in both wild-type and CXCR2-deficient mice 3 h after O3 exposure. However, at 24 h after exposure, responses to inhaled MCh were elevated in wild-type but not CXCR2-deficient mice. These results indicate CXCR2 is essential for maximal neutrophil recruitment, epithelial cell sloughing, and persistent increases in MCh responsiveness after an acute O3 exposure.

scholarly journals Resistin deficiency in mice has no effect on pulmonary responses induced by acute ozone exposure

2015 ◽  
Vol 309 (10) ◽  
pp. L1174-L1185 ◽  
Author(s):  
Shehla S. Razvi ◽  
Jeremy B. Richards ◽  
Farhan Malik ◽  
Kevin R. Cromar ◽  
Roger E. Price ◽  
...  
Keyword(s):  
Inflammatory Cytokines ◽  
Lavage Fluid ◽  
Air Pollutant ◽  
Acute Exposure ◽  
Ozone Exposure ◽  
Type I ◽  
Lung Pathology ◽  
Wild Type ◽  
Human Resistin ◽  
Deficient Mice

Acute exposure to ozone (O3), an air pollutant, causes pulmonary inflammation, airway epithelial desquamation, and airway hyperresponsiveness (AHR). Pro-inflammatory cytokines—including IL-6 and ligands of chemokine (C-X-C motif) receptor 2 [keratinocyte chemoattractant (KC) and macrophage inflammatory protein (MIP)-2], TNF receptor 1 and 2 (TNF), and type I IL-1 receptor (IL-1α and IL-1β)—promote these sequelae. Human resistin, a pleiotropic hormone and cytokine, induces expression of IL-1α, IL-1β, IL-6, IL-8 (the human ortholog of murine KC and MIP-2), and TNF. Functional differences exist between human and murine resistin; yet given the aforementioned observations, we hypothesized that murine resistin promotes O3-induced lung pathology by inducing expression of the same inflammatory cytokines as human resistin. Consequently, we examined indexes of O3-induced lung pathology in wild-type and resistin-deficient mice following acute exposure to either filtered room air or O3. In wild-type mice, O3 increased bronchoalveolar lavage fluid (BALF) resistin. Furthermore, O3 increased lung tissue or BALF IL-1α, IL-6, KC, TNF, macrophages, neutrophils, and epithelial cells in wild-type and resistin-deficient mice. With the exception of KC, which was significantly greater in resistin-deficient compared with wild-type mice, no genotype-related differences in the other indexes existed following O3 exposure. O3 caused AHR to acetyl-β-methylcholine chloride (methacholine) in wild-type and resistin-deficient mice. However, genotype-related differences in airway responsiveness to methacholine were nonexistent subsequent to O3 exposure. Taken together, these data demonstrate that murine resistin is increased in the lungs of wild-type mice following acute O3 exposure but does not promote O3-induced lung pathology.

scholarly journals Pulmonary responses to subacute ozone exposure in obese vs. lean mice

2009 ◽  
Vol 107 (5) ◽  
pp. 1445-1452 ◽  
Author(s):  
Stephanie A. Shore ◽  
Jason E. Lang ◽  
David I. Kasahara ◽  
Frank L. Lu ◽  
Norah G. Verbout ◽  
...  
Keyword(s):  
No Reduction ◽  
Neutrophil Recruitment ◽  
Ozone Exposure ◽  
Pulmonary Injury ◽  
Obese Mice ◽  
Wild Type ◽  
Neutrophilic Inflammation ◽  
Fat Diets ◽  
Deficient Mice

The purpose of this study was to determine whether obesity affects pulmonary responses following a 3-day ozone exposure. Obese db/ db and lean wild-type mice were exposed to ozone (0.3 ppm) for 72 h. In wild-type mice, ozone exposure caused pulmonary injury and inflammation, and these events were associated with reduced pulmonary compliance. In db/ db mice, ozone-induced neutrophil recruitment to the lung was reduced and no reduction in compliance was observed. Similar results were obtained in obese Cpe fat mice, indicating that loss of leptin signaling in db/ db mice does not account for these obesity-related changes. To examine the role of interleukin (IL)-6 in this obesity-related difference in ozone responsiveness, wild-type and IL-6-deficient mice were raised on 10% or 60% fat diets. Compared with 10% fat-fed mice, wild-type 60% fat-fed mice were obese and had reduced neutrophil recruitment following ozone. IL-6 deficiency reduced ozone-induced neutrophil recruitment in 10% fat-fed mice. In contrast, in obese mice, no effect of IL-6 deficiency on neutrophil recruitment was observed. Obesity-related differences in the effect of ozone on compliance were observed in both wild-type and IL-6-deficient mice. Obesity-related differences in serum IL-6 were observed and may account for obesity-related differences in the effect of IL-6 deficiency on neutrophil recruitment. In summary, the neutrophilic inflammation induced by prolonged low level ozone exposure was attenuated in obese mice and appeared to result from an absence of IL-6-dependent neutrophil recruitment in the obese mice.

scholarly journals Altered V-ATPase expression in renal intercalated cells isolated from B1 subunit-deficient mice by fluorescence-activated cell sorting

2013 ◽  
Vol 304 (5) ◽  
pp. F522-F532 ◽  
Author(s):  
Luca Vedovelli ◽  
John T. Rothermel ◽  
Karin E. Finberg ◽  
Carsten A. Wagner ◽  
Anie Azroyan ◽  
...  
Keyword(s):  
Cell Sorting ◽  
Collecting Duct ◽  
Egfp Expression ◽  
Intercalated Cells ◽  
Wild Type ◽  
Western Blots ◽  
Atpase Subunit ◽  
Protein Levels ◽  
Baseline Conditions ◽  
Deficient Mice

Unlike human patients with mutations in the 56-kDa B1 subunit isoform of the vacuolar proton-pumping ATPase (V-ATPase), B1-deficient mice (Atp6v1b1−/−) do not develop metabolic acidosis under baseline conditions. This is due to the insertion of V-ATPases containing the alternative B2 subunit isoform into the apical membrane of renal medullary collecting duct intercalated cells (ICs). We previously reported that quantitative Western blots (WBs) from whole kidneys showed similar B2 protein levels in Atp6v1b1−/− and wild-type mice (Păunescu TG, Russo LM, Da Silva N, Kovacikova J, Mohebbi N, Van Hoek AN, McKee M, Wagner CA, Breton S, Brown D. Am J Physiol Renal Physiol 293: F1915–F1926, 2007). However, WBs from renal medulla (including outer and inner medulla) membrane and cytosol fractions reveal a decrease in the levels of the ubiquitous V-ATPase E1 subunit. To compare V-ATPase expression specifically in ICs from wild-type and Atp6v1b1−/− mice, we crossed mice in which EGFP expression is driven by the B1 subunit promoter (EGFP-B1+/+ mice) with Atp6v1b1−/− mice to generate novel EGFP-B1−/− mice. We isolated pure IC populations by fluorescence-assisted cell sorting from EGFP-B1+/+ and EGFP-B1−/− mice to compare their V-ATPase subunit protein levels. We report that V-ATPase A, E1, and H subunits are all significantly downregulated in EGFP-B1−/− mice, while the B2 protein level is considerably increased in these animals. We conclude that under baseline conditions B2 upregulation compensates for the lack of B1 and is sufficient to maintain basal acid-base homeostasis, even when other V-ATPase subunits are downregulated.

Interactions Between Leukotriene C4 and Interleukin 13 Signaling Pathways in a Mouse Model of Airway Disease

2006 ◽  
Vol 130 (4) ◽  
pp. 440-446
Author(s):  
Jaime Chavez ◽  
Hays W. J. Young ◽  
David B. Corry ◽  
Michael W. Lieberman
Keyword(s):  
Signaling Pathways ◽  
Airway Disease ◽  
Lavage Fluid ◽  
Airway Responsiveness ◽  
Leukotriene C4 ◽  
Wild Type ◽  
Transcript Levels ◽  
Interleukin 13 ◽  
Deficient Mice ◽  
Intranasal Instillation

Abstract Context.—During an asthmatic episode, leukotriene C4 (LTC4) and interleukin 13 (IL-13) are released into the airways and are thought to be central mediators of the asthmatic response. However, little is known about how these molecules interact or affect each other's signaling pathway. Objective.—To determine if the LTC4 and IL-13 signaling pathways interact with each other's pathways. Design.—We examined airway responsiveness, cysteinyl LTs (Cys-LTs), and Cys-LT and IL-13 receptor transcript levels in wild-type mice and in mice that were deficient in γ-glutamyl leukotrienase (an enzyme that converts LTC4 to LTD4), STAT6 (signal transducer and activator of transcription 6 [a critical molecule in IL-13 signaling]), and IL-4Rα (a subunit of the IL-13 receptor). Results.—Wild-type (C57BL/129SvEv) and γ-glutamyl leukotrienase–deficient mice showed increased airway responsiveness after intranasal instillation of IL-13; similar results were observed after intranasal instillation of IL-13 or LTC4 in a second wild-type strain (BALB/c). Interleukin 13 treatment reduced levels of Cys-LTs in bronchoalveolar lavage fluid. This change was unaccompanied by changes in other arachidonic acid metabolites or in RNA transcript levels of enzymes associated with Cys-LT synthesis. Interleukin 13 treatment also increased transcript levels of the Cys-LT 1 and Cys-LT 2 receptors, while LTC4 increased transcript levels of the α1 chain of the IL-13 receptor. Furthermore, IL-4Rα–deficient mice had increased airway responsiveness to LTC4 but not to IL-13, whereas STAT6-deficient mice failed to respond to either agonist. Conclusions.—These findings indicate that LTC4 and IL-13 are dependent on or signal through STAT6 to increase airway responsiveness and that both agonists regulate expression of each other's receptors.

scholarly journals Molecular Alterations in the Stomach of Tff1-Deficient Mice: Early Steps in Antral Carcinogenesis

2020 ◽  
Vol 21 (2) ◽  
pp. 644 ◽  
Author(s):  
Eva B. Znalesniak ◽  
Franz Salm ◽  
Werner Hoffmann
Keyword(s):  
Cysteine Residue ◽  
Molecular Forms ◽  
Amino Acid Residues ◽  
Wild Type ◽  
Rt Pcr ◽  
Molecular Alterations ◽  
Protein Levels ◽  
Increased Sensitivity ◽  
A Minor ◽  
Deficient Mice

TFF1 is a peptide of the gastric mucosa co-secreted with the mucin MUC5AC. It plays a key role in gastric mucosal protection and repair. Tff1-deficient (Tff1KO) mice obligatorily develop antropyloric adenoma and about 30% progress to carcinomas. Thus, these mice represent a model for gastric tumorigenesis. Here, we compared the expression of selected genes in Tff1KO mice and the corresponding wild-type animals (RT-PCR analyses). Furthermore, we systematically investigated the different molecular forms of Tff1 and its heterodimer partner gastrokine-2 (Gkn2) in the stomach (Western blot analyses). As a hallmark, a large portion of murine Tff1 occurs in a monomeric form. This is unexpected because of its odd number of seven cysteine residues. Probably the three conserved acid amino acid residues (EEE) flanking the 7th cysteine residue allow monomeric secretion. As a consequence, the free thiol of monomeric Tff1 could have a protective scavenger function, e.g., for reactive oxygen/nitrogen species. Furthermore, a minor subset of Tff1 forms a disulfide-linked heterodimer with IgG Fc binding protein (Fcgbp). Of special note, in Tff1KO animals a homodimeric form of Gkn2 was observed. In addition, Tff1KO animals showed strongly reduced Tff2 transcript and protein levels, which might explain their increased sensitivity to Helicobacter pylori infection.

scholarly journals Syndecan-4 Inhibits the Development of Pulmonary Fibrosis by Attenuating TGF-β Signaling

2019 ◽  
Vol 20 (20) ◽  
pp. 4989 ◽  
Author(s):  
Yoshinori Tanino ◽  
Xintao Wang ◽  
Takefumi Nikaido ◽  
Kenichi Misa ◽  
Yuki Sato ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Heparan Sulfate ◽  
Bronchoalveolar Lavage Fluid ◽  
Pulmonary Inflammation ◽  
Lavage Fluid ◽  
Lung Fibroblasts ◽  
Fibrosis Score ◽  
Wild Type ◽  
Deficient Mice

Syndecan-4 is a transmembrane heparan sulfate proteoglycan expressed in a variety of cells, and its heparan sulfate glycosaminoglycan side chains bind to several proteins exhibiting various biological roles. The authors have previously demonstrated syndecan-4′s critical roles in pulmonary inflammation. In the current study, however, its role in pulmonary fibrosis was evaluated. Wild-type and syndecan-4-deficient mice were injected with bleomycin, and several parameters of inflammation and fibrosis were analyzed. The mRNA expression of collagen and α-smooth muscle action (α-SMA) in lung tissues, as well as the histopathological lung fibrosis score and collagen content in lung tissues, were significantly higher in the syndecan-4-deficient mice. However, the total cell count and cell differentiation in bronchoalveolar lavage fluid were equivalent between the wild-type and syndecan-4-deficient mice. Although there was no difference in the TGF-β expression in lung tissues between the wild-type and syndecan-4-deficient mice, significantly more activation of Smad3 in lung tissues was observed in the syndecan-4-deficient mice compared to the wild-type mice. Furthermore, in the in vitro experiments using lung fibroblasts, the co-incubation of syndecan-4 significantly inhibited TGF-β-induced Smad3 activation, collagen and α-SMA upregulation. Moreover, syndecan-4 knock-down by siRNA increased TGF-β-induced Smad3 activation and upregulated collagen and α-SMA expression. These findings showed that syndecan-4 inhibits the development of pulmonary fibrosis, at least in part, through attenuating TGF-β signaling.

scholarly journals Pivotal role of IL-6 in the hyperinflammatory responses to subacute ozone in adiponectin-deficient mice

2014 ◽  
Vol 306 (6) ◽  
pp. L508-L520 ◽  
Author(s):  
David I. Kasahara ◽  
Hye Y. Kim ◽  
Joel A. Mathews ◽  
Norah G. Verbout ◽  
Alison S. Williams ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Γδ T Cells ◽  
Pivotal Role ◽  
Ozone Exposure ◽  
Granulocyte Colony Stimulating Factor ◽  
Wild Type ◽  
Neutrophilic Inflammation ◽  
Stimulating Factor ◽  
Deficient Mice

Adiponectin is an adipose-derived hormone with anti-inflammatory activity. Following subacute ozone exposure (0.3 ppm for 24–72 h), neutrophilic inflammation and IL-6 are augmented in adiponectin-deficient ( Adipo−/−) mice. The IL-17/granulocyte colony-stimulating factor (G-CSF) axis is required for this increased neutrophilia. We hypothesized that elevated IL-6 in Adipo−/−mice contributes to their augmented responses to ozone via effects on IL-17A expression. Therefore, we generated mice deficient in both adiponectin and IL-6 ( Adipo−/−/IL-6−/−) and exposed them to ozone or air. In ozone-exposed mice, bronchoalveolar lavage (BAL) neutrophils, IL-6, and G-CSF, and pulmonary Il17a mRNA expression were greater in Adipo−/−vs. wild-type mice, but reduced in Adipo−/−/IL-6−/−vs. Adipo−/−mice. IL-17A+F4/80+cells and IL-17A+γδ T cells were also reduced in Adipo−/−/IL-6−/−vs. Adipo−/−mice exposed to ozone. Only BAL neutrophils were reduced in IL-6−/−vs. wild-type mice. In wild-type mice, IL-6 was expressed in Gr-1+F4/80−CD11c−cells, whereas in Adipo−/−mice F4/80+CD11c+cells also expressed IL-6, suggesting that IL-6 is regulated by adiponectin in these alveolar macrophages. Transcriptomic analysis identified serum amyloid A3 ( Saa3), which promotes IL-17A expression, as the gene most differentially augmented by ozone in Adipo−/−vs. wild-type mice. After ozone, Saa3 mRNA expression was markedly greater in Adipo−/−vs. wild-type mice but reduced in Adipo−/−/IL-6−/−vs. Adipo−/−mice. In conclusion, our data support a pivotal role of IL-6 in the hyperinflammatory condition observed in Adipo−/−mice after ozone exposure and suggest that this role of IL-6 involves its ability to induce Saa3, IL-17A, and G-CSF.

ICAM-1 and LFA-1 play critical roles in LPS-induced neutrophil recruitment into the alveolar space

2006 ◽  
Vol 291 (2) ◽  
pp. L200-L207 ◽  
Author(s):  
Abdul Basit ◽  
Joerg Reutershan ◽  
Margaret A. Morris ◽  
Michael Solga ◽  
C. Edward Rose ◽  
...  
Keyword(s):  
Lung Inflammation ◽  
Critical Role ◽  
Fold Increase ◽  
Lavage Fluid ◽  
Neutrophil Recruitment ◽  
Intercellular Adhesion Molecule ◽  
Lymphocyte Function ◽  
Alveolar Space ◽  
Wild Type ◽  
Intercellular Adhesion Molecule 1

Neutrophil recruitment into lung constitutes a major response to airborne endotoxins. In many tissues endothelial intercellular adhesion molecule-1 (ICAM-1) interacts with lymphocyte function associated antigen-1 (LFA-1) on neutrophils, and this interaction plays a critical role in neutrophil recruitment. There are conflicting reports about the role of ICAM-1 in neutrophil recruitment into lungs. We studied neutrophil recruitment into alveolar space in a murine model of aerosolized LPS-induced lung inflammation. LPS induces at least a 100-fold increase in neutrophil numbers in alveolar space, as determined by flow cytometry of bronchoalveolar lavage fluid. Neutrophil recruitment was reduced by 54% in ICAM-1 null mice and by 45% in LFA-1 null mice. In wild-type mice treated with anti-ICAM-1 and anti-LFA-1 antibodies, there was 51 and 58% reduction in the neutrophil recruitment, respectively. In chimeric mice, generated by the transplantation of mixtures of bone marrows from LFA-1 null and wild-type mice, the normalized recruitment of LFA-1 null neutrophils was reduced by 60% compared with wild-type neutrophils. Neither the treatment of ICAM-1 null mice with a function-blocking antibody to LFA-1 nor the treatment of LFA-1 null mice with anti-ICAM-1 antibody resulted in further reduction in the recruitment compared with untreated ICAM-1 null and LFA-1 null mice. We conclude that ICAM-1 and LFA-1 play critical roles in the recruitment of neutrophils into the alveolar space in aerosolized LPS-induced lung inflammation, and LFA-1 serves as a ligand of ICAM-1 in the lung.

scholarly journals Effect of PAR-2 Deficiency in Mice on KC Expression after Intratracheal LPS Administration

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Julie C. Williams ◽  
Rebecca D. Lee ◽  
Claire M. Doerschuk ◽  
Nigel Mackman
Keyword(s):  
Lung Inflammation ◽  
Lavage Fluid ◽  
Peritoneal Macrophages ◽  
Wild Type ◽  
Protease Activated Receptors ◽  
Tlr4 Signaling ◽  
Bronchial Lavage ◽  
Lps Activation ◽  
Deficient Mice

Protease activated receptors (PAR) have been shown to play a role in inflammation. PAR-2 is expressed by numerous cells in the lung and has either proinflammatory, anti-inflammatory, or no effect depending on the model. Here, we examined the role of PAR-2 in a model of LPS-induced lung inflammation. We found that PAR-2-deficient mice had significantly less KC expression in bronchial lavage fluid compared with wild-type mice but there was no difference in MIP-2 or TNF-α expression. We also found that isolated alveolar and resident peritoneal macrophages lacking PAR-2 showed a similar deficit in KC after LPS stimulation without differences in MIP-2 or TNF-α. Infiltration of neutrophils and macrophages into the lung following LPS administration was not affected by an absence of PAR-2. Our results support the notion that PAR-2 plays a role in LPS activation of TLR4 signaling in macrophages.

scholarly journals Disassociation of insulin action and Akt/FOXO signaling in skeletal muscle of older Akt-deficient mice

2012 ◽  
Vol 303 (11) ◽  
pp. R1186-R1194 ◽  
Author(s):  
Thomas H. Reynolds ◽  
Erin Merrell ◽  
Nicholas Cinquino ◽  
Megan Gaugler ◽  
Lily Ng
Keyword(s):  
High Fat Diet ◽  
Insulin Action ◽  
Mrna Levels ◽  
Wild Type ◽  
Akt Phosphorylation ◽  
Protein Levels ◽  
Akt Isoforms ◽  
Forkhead Box ◽  
Gene Ablation ◽  
Deficient Mice

The purpose of the present study was to determine the effect of Akt gene ablation on Akt/Forkhead Box O (FOXO) signaling and atrogene expression. This was accomplished by studying wild-type (WT) and isoform-specific Akt knockout (Akt1−/− and Akt2−/−) mice. The ability of insulin to promote Akt phosphorylation on Ser473 was significantly lower in extensor digitorum longus (EDL) and soleus muscles from Akt1−/− and Akt2−/− mice compared with WT mice. Total Akt1 protein levels were significantly lower in EDL muscles of Akt2−/− mice compared with WT mice, a process that appears to be posttranscriptionally regulated as Akt1 mRNA levels were unchanged. The loss of Akt1 protein in EDL muscles of Akt2−/− mice does not appear to be due to insulin resistance because 4 mo of a high-fat diet failed to reduce Akt1 protein levels in muscles of WT mice. Although FOXO3a phosphorylation and atrogin-1 expression were unaltered in muscles of Akt1−/− and Akt2−/− mice, the expression of the atrogenes Bnip3 and gabarapl were significantly elevated in muscles of both Akt1 and Akt2 knockout mice. Finally, the expression of striated activator of Rho signaling was significantly increased in muscles of Akt2−/− mice compared with Akt1−/− and WT mice. Our results demonstrate that the ablation of Akt isoforms disassociates insulin action and Akt/FOXO signaling to atrogenes.

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