scholarly journals Kinetic profiling of in vivo lung cellular inflammatory responses to mechanical ventilation

2015 ◽  
Vol 308 (9) ◽  
pp. L912-L921 ◽  
Author(s):  
Samantha J. Woods ◽  
Alicia A. C. Waite ◽  
Kieran P. O'Dea ◽  
Paul Halford ◽  
Masao Takata ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Alveolar Macrophages ◽  
Inflammatory Responses ◽  
Alveolar Epithelium ◽  
Cell Types ◽  
Activation Mechanism ◽  
Pulmonary Vasculature ◽  
Cellular Activation ◽  
Pulmonary Endothelium

Mechanical ventilation, through overdistension of the lung, induces substantial inflammation that is thought to increase mortality among critically ill patients. The mechanotransduction processes involved in converting lung distension into inflammation during this ventilator-induced lung injury (VILI) remain unclear, although many cell types have been shown to be involved in its pathogenesis. This study aimed to identify the profile of in vivo lung cellular activation that occurs during the initiation of VILI. This was achieved using a flow cytometry-based method to quantify the phosphorylation of several markers (p38, ERK1/2, MAPK-activated protein kinase 2, and NF-κB) of inflammatory pathway activation within individual cell types. Anesthetized C57BL/6 mice were ventilated with low (7 ml/kg), intermediate (30 ml/kg), or high (40 ml/kg) tidal volumes for 1, 5, or 15 min followed by immediate fixing and processing of the lungs. Surprisingly, the pulmonary endothelium was the cell type most responsive to in vivo high-tidal-volume ventilation, demonstrating activation within just 1 min, followed by the alveolar epithelium. Alveolar macrophages were the slowest to respond, although they still demonstrated activation within 5 min. This order of activation was specific to VILI, since intratracheal lipopolysaccharide induced a very different pattern. These results suggest that alveolar macrophages may become activated via a secondary mechanism that occurs subsequent to activation of the parenchyma and that the lung cellular activation mechanism may be different between VILI and lipopolysaccharide. Our data also demonstrate that even very short periods of high stretch can promote inflammatory activation, and, importantly, this injury may be immediately manifested within the pulmonary vasculature.

Inhibition of monocyte-derived inflammatory cytokines by IL-25 occurs via p38 Map kinase–dependent induction of Socs-3

Blood ◽  
2009 ◽  
Vol 113 (15) ◽  
pp. 3512-3519 ◽  
Author(s):  
Roberta Caruso ◽  
Carmine Stolfi ◽  
Massimiliano Sarra ◽  
Angelamaria Rizzo ◽  
Massimo C. Fantini ◽  
...  
Keyword(s):  
Map Kinase ◽  
Inflammatory Cytokines ◽  
Inflammatory Responses ◽  
Human Peripheral Blood ◽  
Serum Levels ◽  
Cell Types ◽  
P38 Map Kinase ◽  
Negative Regulator ◽  
Therapeutic Implications

Abstract IL-25, a member of the IL-17 cytokine family, is known to enhance Th2-like responses associated with increased serum levels of IgE, IgG1, IgA, blood eosinophilia, and eosinophilic infiltrates in various tissues. However, IL-25 also abrogates inflammatory responses driven by Th17 cells. However, the cell types that respond to IL-25 and the mechanisms by which IL-25 differentially regulates immune reactions are not well explored. To identify potential targets of IL-25, we initially examined IL-25 receptor (IL-25R) in human peripheral blood cells. IL-25R was predominantly expressed by CD14+ cells. We next assessed the functional role of IL-25 in modulating the response of CD14+ cells to various inflammatory signals. CD14+ cells responded to IL-25 by down-regulating the synthesis of inflammatory cytokines induced by toll-like receptor (TLR) ligands and inflammatory cytokines. Inhibition of cytokine response by IL-25 occurred via a p38 Map kinase–driven Socs-3–dependent mechanism. In vivo, IL-25 inhibited monocyte-derived cytokines and protected against LPS-induced lethal endotoxemia in mice. These data indicate that IL-25 is a negative regulator of monocyte proinflammatory cytokine responses, which may have therapeutic implications.

scholarly journals Induction of Apoptosis of Metastatic Mammary Carcinoma Cells In Vivo by Disruption of Tumor Cell Surface CD44 Function

1997 ◽  
Vol 186 (12) ◽  
pp. 1985-1996 ◽  
Author(s):  
Qin Yu ◽  
Bryan P. Toole ◽  
Ivan Stamenkovic
Keyword(s):  
Cell Surface ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Lung Tissue ◽  
Mammary Carcinoma ◽  
Cell Types ◽  
Pulmonary Endothelium ◽  
Soluble Cd44

To understand how the hyaluronan receptor CD44 regulates tumor metastasis, the murine mammary carcinoma TA3/St, which constitutively expresses cell surface CD44, was transfected with cDNAs encoding soluble isoforms of CD44 and the transfectants (TA3sCD44) were compared with parental cells (transfected with expression vector only) for growth in vivo and in vitro. Local release of soluble CD44 by the transfectants inhibited the ability of endogenous cell surface CD44 to bind and internalize hyaluronan and to mediate TA3 cell invasion of hyaluronan-producing cell monolayers. Mice intravenously injected with parental TA3/St cells developed massive pulmonary metastases within 21–28 d, whereas animals injected with TA3sCD44 cells developed few or no tumors. Tracing of labeled parental and transfectant tumor cells revealed that both cell types initially adhered to pulmonary endothelium and penetrated the interstitial stroma. However, although parental cells were dividing and forming clusters within lung tissue 48 h following injection, >80% of TA3sCD44 cells underwent apoptosis. Although sCD44 transfectants displayed a marked reduction in their ability to internalize and degrade hyaluronan, they elicited abundant local hyaluronan production within invaded lung tissue, comparable to that induced by parental cells. These observations provide direct evidence that cell surface CD44 function promotes tumor cell survival in invaded tissue and that its suppression can induce apoptosis of the invading tumor cells, possibly as a result of impairing their ability to penetrate the host tissue hyaluronan barrier.

scholarly journals Constitutive nitric oxide production by rat alveolar macrophages

1998 ◽  
Vol 274 (3) ◽  
pp. L360-L368 ◽  
Author(s):  
P. R. Miles ◽  
L. Bowman ◽  
A. Rengasamy ◽  
L. Huffman
Keyword(s):  
Nitric Oxide ◽  
Alveolar Macrophage ◽  
Alveolar Macrophages ◽  
Lung Surfactant ◽  
Calcium Ionophore ◽  
Cell Types ◽  
Alveolar Type ◽  
No Production ◽  
No Formation

Results from previous studies suggest that alveolar macrophages must be exposed to inflammatory stimuli to produce nitric oxide (⋅ NO). In this study, we report that naive unstimulated rat alveolar macrophages do produce ⋅ NO and attempt to characterize this process. Western blot analysis demonstrates that the enzyme responsible is an endothelial nitric oxide synthase (eNOS). No brain or inducible NOS can be detected. The rate of ⋅ NO production is ∼0.07 nmol ⋅ 106cells−1 ⋅ h−1, an amount that is less than that produced by the eNOS found in alveolar type II or endothelial cells. Alveolar macrophage ⋅ NO formation is increased in the presence of extracellularl-arginine, incubation medium containing magnesium and no calcium, a calcium ionophore (A-23187), or methacholine. ⋅ NO production is inhibited by N G-nitro-l-arginine methyl ester (l-NAME) but not by N G-nitro-l-arginine,l- N 5-(1-iminomethyl)ornithine hydrochloride, or aminoguanidine. Incubation with ATP, ADP, or histamine also inhibits ⋅ NO formation. Some of these properties are similar to and some are different from properties of eNOS in other cell types. Cellular ⋅ NO levels do not appear to be related to ATP or lactate content. Alveolar macrophage production of ⋅ NO can be increased approximately threefold in the presence of lung surfactant or its major component, dipalmitoyl phosphatidylcholine (DPPC). The DPPC-induced increase in ⋅ NO formation is time and concentration dependent, can be completely inhibited by l-NAME, and does not appear to be related to the degradation of DPPC by alveolar macrophages. These results demonstrate that unstimulated alveolar macrophages produce ⋅ NO via an eNOS and that lung surfactant increases ⋅ NO formation. This latter effect may be important in maintaining an anti-inflammatory state in vivo.

Impairment of cation transport in A549 cells and rat alveolar epithelial cells by hypoxia

1997 ◽  
Vol 273 (4) ◽  
pp. L797-L806 ◽  
Author(s):  
Heimo Mairbäurl ◽  
Ralf Wodopia ◽  
Sigrid Eckes ◽  
Susanne Schulz ◽  
Peter Bärtsch
Keyword(s):  
Epithelial Cells ◽  
A549 Cells ◽  
Alveolar Epithelium ◽  
Cell Types ◽  
Cation Transport ◽  
Alveolar Epithelial Cells ◽  
Alveolar Type ◽  
Water Reabsorption ◽  
Alveolar Epithelial

A reduced cation reabsorption across the alveolar epithelium decreases water reabsorption from the alveoli and could diminish clearing accumulated fluid. To test whether hypoxia restricts cation transport in alveolar epithelial cells, cation uptake was measured in rat lung alveolar type II pneumocytes (AII cells) in primary culture and in A549 cells exposed to normoxia and hypoxia. In AII and A549 cells, hypoxia caused a[Formula: see text]-dependent inhibition of the Na-K pump, of Na-K-2Cl cotransport, and of total and amiloride-sensitive22Na uptake. Nifedipine failed to prevent hypoxia-induced transport inhibition in both cell types. In A549 cells, the inhibition of the Na-K pump and Na-K-2Cl cotransport occurred within ∼30 min of hypoxia, was stable >20 h, and was reversed by 2 h of reoxygenation. There was also a reduction in cell membrane-associated Na-K-ATPase and a decrease in Na-K-2Cl cotransport flux after full activation with calyculin A, indicating a decreased transport capacity. [14C]serine incorporation into cell proteins was reduced in hypoxic A549 cells, but inhibition of protein synthesis with cycloheximide did not reduce ion transport. In AII and A549 cells, ATP levels decreased slightly, and ADP and the ATP-to-ADP ratio were unchanged after 4 h of hypoxia. In A549 cells, lactate, intracellular Na, and intracellular K were unchanged. These results indicate that hypoxia inhibits apical Na entry pathways and the basolateral Na-K pump in A549 cells and rat AII pneumocytes in culture, indicating a hypoxia-induced reduction of transepithelial Na transport and water reabsorption by alveolar epithelium. If similar changes occur in vivo, the impaired cation transport across alveolar epithelial cells might contribute to the formation of hypoxic pulmonary edema.

scholarly journals Inflammation-Induced Alternative Pre-mRNA Splicing in Mouse Alveolar Macrophages

2019 ◽  
Vol 10 (2) ◽  
pp. 555-567 ◽  
Author(s):  
William J. Janssen ◽  
Thomas Danhorn ◽  
Chelsea Harris ◽  
Kara J. Mould ◽  
Frank Fang-Yao Lee ◽  
...  
Keyword(s):  
Alveolar Macrophages ◽  
Inflammatory Responses ◽  
Tricarboxylic Acid Cycle ◽  
Mrna Splicing ◽  
Dynamic Responses ◽  
Chemokine Signaling ◽  
A Genome ◽  
Wide Scale

Alveolar macrophages serve as central orchestrators of inflammatory responses in the lungs, both initiating their onset and promoting their resolution. However, the mechanisms that program macrophages for these dynamic responses are not fully understood. Over 95% of all mammalian genes undergo alternative pre-mRNA splicing. While alternative splicing has been shown to regulate inflammatory responses in macrophages in vitro, it has not been investigated on a genome-wide scale in vivo. Here we used RNAseq to investigate alternative pre-mRNA splicing in alveolar macrophages isolated from lipopolysaccharide (LPS)-treated mice during the peak of inflammation and during its resolution. We found that lung inflammation induced substantial alternative pre-mRNA splicing in alveolar macrophages. The number of changes in isoform usage was greatest at the peak of inflammation and involved multiple classes of alternative pre-mRNA splicing events. Comparative pathway analysis of inflammation-induced changes in alternative pre-mRNA splicing and differential gene expression revealed overlap of pathways enriched for immune responses such as chemokine signaling and cellular metabolism. Moreover, alternative pre-mRNA splicing of genes in metabolic pathways differed in tissue resident vs. recruited (blood monocyte-derived) alveolar macrophages and corresponded to changes in core metabolism, including a switch to Warburg-like metabolism in recruited macrophages with increased glycolysis and decreased flux through the tricarboxylic acid cycle.

Geranylgeranyl diphosphate synthase deficiency hyperactivates macrophages and aggravates lipopolysaccharide-induced acute lung injury

2021 ◽  
Author(s):  
Jiajia Jin ◽  
Hong Qian ◽  
Bing Wan ◽  
Li Zhou ◽  
Cen Chen ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Alveolar Macrophages ◽  
Macrophage Activation ◽  
Nuclear Translocation ◽  
Inflammatory Responses ◽  
Alveolar Epithelium ◽  
Geranylgeranyl Diphosphate Synthase ◽  
Geranylgeranyl Diphosphate

Macrophage activation is a key contributing factor for excessive inflammatory responses of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Geranylgeranyl diphosphate synthase (GGPPS) plays a key role in the development of inflammatory diseases. Our group previously showed that GGPPS in alveolar epithelium have deleterious effects on acute lung injury induced by LPS or mechanical ventilation. Herein, we examined the role of GGPPS in modulating macrophage activation in ALI/ARDS. We found significant increased GGPPS expression in alveolar macrophages in ARDS patients compared to healthy volunteers and in ALI mice induced by LPS. GGPPS-floxed control (GGPPSfl/fl) and myeloid-selective knockout (GGPPSfl/flLysMcre) mice were then generated. Interestingly, using a LPS-induced ALI mouse model, we showed that myeloid-specific GGPPS knockout significantly increased mortality, aggravated lung injury, and increased the accumulation of inflammatory cells, total protein, and inflammatory cytokines in BALF. In vitro, GGPPS deficiency up-regulated the production of LPS-induced IL-6, IL-1β, and TNF-α in alveolar macrophages, bone marrow-derived macrophages (BMDMs), and THP-1 cells. Mechanistically, GGPPS knockout increased phosphorylation and nuclear translocation of NF-κB p65 induced by LPS. In addition, GGPPS deficiency increased the level of GTP-Rac1, which was responsible for NF-κB activation. In conclusion, decreased expression of GGPPS in macrophages aggravates lung injury and inflammation in ARDS, at least partly by regulating Rac1-dependent NF-κB signaling. GGPPS in macrophages may represent a novel therapeutic target in ARDS.

Regulation of angiopoietin expression by bacterial lipopolysaccharide

2008 ◽  
Vol 294 (5) ◽  
pp. L955-L963 ◽  
Author(s):  
Mahroo Mofarrahi ◽  
Thamir Nouh ◽  
Salman Qureshi ◽  
Loic Guillot ◽  
Dominique Mayaki ◽  
...  
Keyword(s):  
Tyrosine Phosphorylation ◽  
Inflammatory Responses ◽  
Cell Types ◽  
Vascular Leakage ◽  
Saline Control ◽  
E Coli ◽  
Protein Levels ◽  
Angiopoietin 2

Angiopoietins are ligands for Tie-2 receptors and play important roles in angiogenesis and inflammation. While angiopoietin-1 (Ang-1) inhibits inflammatory responses, angiopoietin-2 (Ang-2) promotes cytokine production and vascular leakage. In this study, we evaluated in vivo and in vitro effects of Escherichia coli lipopolysaccharides (LPS) on angiopoietin expression. Wild-type C57/BL6 mice were injected with saline (control) or E. coli LPS (20 mg/ml ip) and killed 6, 12, and 24 h later. The diaphragm, lung, and liver were excised and assayed for mRNA and protein expression of Ang-1, Ang-2, and Tie-2 protein and tyrosine phosphorylation. LPS injection elicited a severalfold rise in Ang-2 mRNA and protein levels in the three organs. By comparison, both Ang-1 and Tie-2 levels in the diaphragm, liver, and lung were significantly attenuated by LPS administration. In addition, Tie-2 tyrosine phosphorylation in the lung was significantly reduced in response to LPS injection. In vitro exposure to E. coli LPS elicited cell-specific changes in Ang-1 expression, with significant induction in Ang-1 expression being observed in cultured human epithelial cells, whereas significant attenuation of Ang-1 expression was observed in response to E. coli LPS exposure in primary human skeletal myoblasts. In both cell types, E. coli LPS elicited substantial induction of Ang-2 mRNA, a response that was mediated in part through NF-κB. We conclude that in vivo endotoxemia triggers functional inhibition of the Ang-1/Tie-2 receptor pathway by reducing Ang-1 and Tie-2 expression and inducing Ang-2 levels and that this response may contribute to enhanced vascular leakage in sepsis.

scholarly journals Galectin-3 Modulates Immune and Inflammatory Responses during Helminthic Infection: Impact of Galectin-3 Deficiency on the Functions of Dendritic Cells

2007 ◽  
Vol 75 (11) ◽  
pp. 5148-5157 ◽  
Author(s):  
Laetitia Breuilh ◽  
François Vanhoutte ◽  
Josette Fontaine ◽  
Caroline M. W. van Stijn ◽  
Isabelle Tillie-Leblond ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Inflammatory Responses ◽  
Adaptive Immune Response ◽  
Chronic Phase ◽  
Cell Types ◽  
Experimental Models ◽  
Helminthic Infection ◽  
Galectin 3

ABSTRACT Galectin-3 (Gal-3) is a multifunctional β-galactoside-binding lectin that senses self-derived and microbial glycoconjugates. Although Gal-3 is important in immune reactions and host defense in some experimental models, the function of Gal-3 during helminthic diseases (e.g., schistosomiasis) is still elusive. We show that, compared to wild-type Schistosoma mansoni-infected mice, infected Gal-3−/− mice have a reduced number of T and B lymphocytes in the spleen, develop reduced liver granulomas at 7 weeks (acute phase) and 14 weeks (chronic phase) postinfection, and mount a biased cellular and humoral Th1 response. In an attempt to understand this latter phenomenon, we studied the role of endogenous Gal-3 in dendritic cells (DCs), the most potent antigen-presenting cells, both in vitro and in vivo. Although Gal-3 deficiency in DCs does not impact their differentiation and maturation processes, it greatly influences the strength (but not the nature) of the adaptive immune response that they trigger, suggesting that Gal-3 deficiency in some other cell types may be important during murine schistosomiasis. As a whole, this study implies that Gal-3 is a modulator of the immune/inflammatory responses during helminthic infection and reveals for the first time that Gal-3 expression in DCs is pivotal to control the magnitude of T-lymphocyte priming.

scholarly journals Neovascularization in the pulmonary endothelium is regulated by the endosome: Rab4-mediated trafficking and p18-dependent signaling

2015 ◽  
Vol 309 (7) ◽  
pp. L700-L709 ◽  
Author(s):  
Havovi Chichger ◽  
Julie Braza ◽  
Huetran Duong ◽  
Myranda Stark ◽  
Elizabeth O. Harrington
Keyword(s):  
Tube Formation ◽  
Endothelial Cell Migration ◽  
Endothelial Barrier ◽  
Cell Junction ◽  
Pulmonary Vasculature ◽  
Microvascular Endothelial Cell ◽  
Wild Type ◽  
Pulmonary Endothelium

Neovascularization, the formation of new blood vessels, requires multiple processes including vascular leak, migration, and adhesion. Endosomal proteins, such as Rabs, regulate trafficking of key signaling proteins involved in neovascularization. The novel endosome protein, p18, enhances vascular endothelial (VE)-cadherin recycling from early endosome to cell junction to improve pulmonary endothelial barrier function. Since endothelial barrier integrity is vital in neovascularization, we sought to elucidate the role for endosome proteins p18 and Rab4, Rab7, and Rab9 in the process of vessel formation within the pulmonary vasculature. Overexpression of wild-type p18 (p18wt), but not the nonendosomal-binding mutant (p18N39), significantly increased lung microvascular endothelial cell migration, adhesion, and both in vitro and in vivo tube formation. Chemical inhibition of mTOR or p38 attenuated the proneovascularization role of p18wt. Similar to the effect of p18wt, overexpression of prorecycling wild-type (Rab4WT) and endosome-anchored (Rab4Q67L) Rab4 enhanced neovascularization processes, whereas molecular inhibition of Rab4, by using the nonendosomal-binding mutant (Rab4S22N) attenuated VEGF-induced neovascularization. Unlike p18, Rab4-induced neovascularization was independent of mTOR or p38 inhibition but was dependent on p18 expression. This study shows for the first time that neovascularization within the pulmonary vasculature is dependent on the prorecycling endocytic proteins Rab4 and p18.

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