Silica-induced chemokine expression in alveolar  type II cells is mediated by TNF-α

Recent evidence has suggested that epithelial cells may contribute to the inflammatory response in the lung after exposure to crystalline silica through the production of and response to specific growth factors, chemokines, and cytokines. However, the exact cellular and molecular responses of epithelial cells to silica exposure remains unclear. Using a murine alveolar type II cell line [murine lung epithelial (MLE)-15 cell line], we measured the early changes in various cytokine and chemokine mRNA species after exposure of the cells to 4–35 μg/cm2 of silica (cristobalite), interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and lipopolysaccharide (LPS) alone or in combination. Total mRNA was isolated and assayed with an RNase protection assay after 6 and 24 h of exposure. Cristobalite exposure alone led to an increase in monocyte chemotactic protein (MCP)-1, macrophage inflammatory protein (MIP)-2, and regulated on activation normal T cells expressed and secreted (RANTES) mRNAs. Treatment with IFN-γ alone increased MCP-1 mRNA levels. Treatment with TNF-α or LPS alone led to an increase in MCP-1 and MIP-2 mRNA. The combination of cristobalite plus TNF-α led to an additive increase in MCP-1 and MIP-2, whereas cristobalite plus IFN-γ or LPS had a synergistic effect. We also found with a TNF-α-neutralizing antibody that TNF-α plays a major role in mediating the type II cell chemokine response to cristobalite exposure. The results indicate that the cristobalite-induced chemokine response in the lung epithelium is mediated in part by TNF-α and can be enhanced by macrophage- and lymphocyte-derived inflammatory mediators in an additive and synergistic fashion.

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Silica-induced chemokine expression in alveolar type II cells is mediated by TNF-α-induced oxidant stress

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1999.276.6.l979 ◽

1999 ◽

Vol 276 (6) ◽

pp. L979-L988 ◽

Cited By ~ 25

Author(s):

Edward G. Barrett ◽

Carl Johnston ◽

Günter Oberdörster ◽

Jacob N. Finkelstein

Keyword(s):

Epithelial Cells ◽

Oxidant Stress ◽

Rnase Protection Assay ◽

Alveolar Type ◽

Mrna Levels ◽

Ros Production ◽

Type Ii ◽

Acetoxymethyl Ester ◽

Rnase Protection ◽

Tnf Α

We have shown previously that epithelial cells may contribute to the inflammatory response in the lung after exposure to crystalline silica through the production of and response to specific chemokines and cytokines. However, the exact cellular and molecular responses of epithelial cells to silica exposure remain unclear. We hypothesize that non-oxidant-mediated silica-cell interactions lead to the upregulation of tumor necrosis factor-α (TNF-α), whereby TNF-α-induced generation of reactive oxygen species (ROS) leads to the activation of the monocyte chemotactic protein (MCP)-1 and macrophage inflammatory protein (MIP)-2 genes. Using a murine alveolar type II cell line, murine lung epithelial (MLE)-15, we measured the early changes in TNF-α, MCP-1, and MIP-2 mRNA species after exposure of the cells to 18 μg/cm2 silica (cristobalite) in combination with various antioxidants. Total mRNA was isolated and assayed using an RNase protection assay after 6 h of particle exposure. We found that extracellular GSH could completely attenuate the cristobalite-induced expression of MCP-1 and MIP-2 mRNAs, whereas TNF-α mRNA levels were unaltered. We also found using the oxidant-sensitive dye 6-carboxy-2′,7′-dichlorodihydrofluorescein diacetate di(acetoxymethyl ester) that treatment of MLE-15 cells with cristobalite and TNF-α (1 ng/ml) resulted in ROS production. This ROS production could be inhibited with extracellular GSH treatment, and in the case of cristobalite-induced ROS, inhibition was also achieved with an anti-TNF-α antibody. The results support the hypothesis that TNF-α mediates cristobalite-induced MCP-1 and MIP-2 expression through the generation of ROS.

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Connexin expression by alveolar epithelial cells is regulated by extracellular matrix

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.2001.280.2.l191 ◽

2001 ◽

Vol 280 (2) ◽

pp. L191-L202 ◽

Cited By ~ 32

Author(s):

Yihe Guo ◽

Cara Martinez-Williams ◽

Clare E. Yellowley ◽

Henry J. Donahue ◽

D. Eugene Rannels

Keyword(s):

Extracellular Matrix ◽

Epithelial Cells ◽

Gap Junction ◽

Intercellular Communication ◽

Translational Regulation ◽

Alveolar Epithelial Cells ◽

Alveolar Type ◽

Type Ii ◽

Gap Junction Intercellular Communication ◽

Type Ii Cell

Extracellular matrix (ECM) proteins promote attachment, spreading, and differentiation of cultured alveolar type II epithelial cells. The present studies address the hypothesis that the ECM also regulates expression and function of gap junction proteins, connexins, in this cell population. Expression of cellular fibronectin and connexin (Cx) 43 increase in parallel during early type II cell culture as Cx26 expression declines. Gap junction intercellular communication is established over the same interval. Cells plated on a preformed, type II cell-derived, fibronectin-rich ECM demonstrate accelerated formation of gap junction plaques and elevated gap junction intercellular communication. These effects are blocked by antibodies against fibronectin, which cause redistribution of Cx43 protein from the plasma membrane to the cytoplasm. Conversely, cells cultured on a laminin-rich ECM, Matrigel, express low levels of Cx43 but high levels of Cx26, reflecting both transcriptional and translational regulation. Cx26 and Cx43 thus demonstrate reciprocal regulation by ECM constituents.

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Effects of bone marrow-derived mesenchymal stromal cells on gene expression in human alveolar type II cells exposed to TNF-α , IL-1β , and IFN-γ

Physiological Reports ◽

10.14814/phy2.13831 ◽

2018 ◽

Vol 6 (16) ◽

pp. e13831 ◽

Cited By ~ 2

Author(s):

Matthew Schwede ◽

Erin M. Wilfong ◽

Rachel L. Zemans ◽

Patty J. Lee ◽

Claudia dos Santos ◽

...

Keyword(s):

Gene Expression ◽

Bone Marrow ◽

Mesenchymal Stromal Cells ◽

Stromal Cells ◽

Alveolar Type ◽

Type Ii Cells ◽

Type Ii ◽

Alveolar Type Ii Cells ◽

Tnf Α ◽

Ifn Γ

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Cytotoxic effects of cigarette smoke extract on an alveolar type II cell-derived cell line

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.2001.281.2.l509 ◽

2001 ◽

Vol 281 (2) ◽

pp. L509-L516 ◽

Cited By ~ 128

Author(s):

Yuma Hoshino ◽

Tadashi Mio ◽

Sonoko Nagai ◽

Hiroyuki Miki ◽

Isao Ito ◽

...

Keyword(s):

Cell Death ◽

Cell Line ◽

Cigarette Smoke ◽

A549 Cells ◽

Cigarette Smoke Extract ◽

Alveolar Type ◽

Type Ii ◽

Cytotoxic Effects ◽

Alveolar Type Ii Cell ◽

Type Ii Cell

Injury of the alveolar epithelium by cigarette smoke is presumed to be an important process in the pathogenesis of smoking-related pulmonary diseases. We investigated the cytotoxic effects of cigarette smoke extract (CSE) on an alveolar type II cell-derived cell line (A549). CSE caused apoptosis at concentrations of 5% or less and necrosis at 10% or more. When CSE was exposed to air before application to A549 cells, the cytotoxic effects were attenuated. CSE caused cell death without direct contact with the cells. Acrolein and hydrogen peroxide, two major volatile factors in cigarette smoke, caused cell death in a similar manner. Aldehyde dehydrogenase, a scavenger of aldehydes, and N-acetylcysteine, a scavenger of oxidants and aldehydes, completely inhibited CSE-induced apoptosis. CSE and acrolein increased intracellular oxidant activity. In conclusion, apoptosis of alveolar epithelial cells may be one of the mechanisms of lung injury induced by cigarette smoking. This cytotoxic effect might be due to an interaction between aldehydes and oxidants present in CSE or formed in CSE-exposed cells.

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TNF-α induction of IL-6 in alveolar type II epithelial cells: Contributions of JNK/c-Jun/AP-1 element, C/EBPδ/C/EBP binding site and IKK/NF-κB p65/κB site

Molecular Immunology ◽

10.1016/j.molimm.2018.05.004 ◽

2018 ◽

Vol 101 ◽

pp. 585-596 ◽

Cited By ~ 6

Author(s):

Chunguang Yan ◽

Chunmin Deng ◽

Xiufang Liu ◽

Yutong Chen ◽

Jiawei Ye ◽

...

Keyword(s):

Epithelial Cells ◽

Binding Site ◽

Alveolar Type ◽

Type Ii ◽

Tnf Α

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Cytokine regulation of glutamate decarboxylase biosynthesis in isolated rat islets of Langerhans

Biochemical Journal ◽

10.1042/bj3170713 ◽

1996 ◽

Vol 317 (3) ◽

pp. 713-719 ◽

Cited By ~ 11

Author(s):

Robert S. SCHMIDLI ◽

Beverly E. FAULKNER-JONES ◽

Leonard C. HARRISON ◽

Roger F. L. JAMES ◽

Henry J. DeAIZPURUA

Keyword(s):

Protein Synthesis ◽

Glutamate Decarboxylase ◽

Rnase Protection Assay ◽

Rabbit Antiserum ◽

Β Cell ◽

Rnase Protection ◽

Rat Islets ◽

Cell Destruction ◽

Tnf Α ◽

Ifn Γ

Insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease in which cytokines are thought to play an important role in β-cell destruction and immune regulation. A major target of β-cell autoimmunity in IDDM is the enzyme glutamate decarboxylase (GAD). We hypothesized that cytokines in the insulitis lesion modulate the synthesis of GAD. This may, in turn, modify the rate of β-cell destruction. Accordingly we cultured rat islets in the presence and absence of cytokines, and measured synthesis of both isoforms of GAD, GAD65 and GAD67, by [35S]methionine incorporation and immunoprecipitation with a rabbit antiserum that recognizes both GAD65 and GAD67. Incubation of islets with interleukin (IL)-1β (1 ng/ml, 24 h), tumour necrosis factor α (TNF-α; 200 units/ml, 24 h) or interferon γ (IFN-γ; 500 units/ml, 72 h) significantly decreased the synthesis of both GAD65 and GAD67, but reduced neither total protein synthesis nor insulin accumulation in the medium or content. Incubation of islets for 24 h in IFN-α (1000 units/ml), TNF-β (50 ng/ml), IL 2 (1000 units/ml), IL-4 (100 ng/ml), IL-6 (10 ng/ml), IL-10 (20 ng/ml), IL-12 (10 ng/ml) or transforming growth factor β2 (TGF-β2; 5 ng/ml) did not significantly alter GAD65 or GAD67 synthesis. Inhibition of GAD65 and GAD67 protein synthesis by IL-1β, TNF-α or IFN-γ was reversed by co-incubation with the nitric oxide synthase inhibitor, NG-monomethyl arginine (NMMA). Expression of both GAD65 and GAD67 mRNA, measured by RNase protection assay, was also decreased by IL-1β and completely restored to baseline levels by NMMA. Thus the synthesis of both isoforms of islet GAD is selectively decreased in the presence of IL-1β, TNF-α or IFN-γ by a NO-mediated mechanism, probably at the level of cytokine gene transcription. As GAD autoimmunity has been previously shown to have a pathogenic role in an animal model of IDDM, its inhibition by cytokines might limit the immune response, thereby regulating the rate of β-cell destruction in IDDM.

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Rat lung alveolar type II cell line maintains sodium transport characteristics of primary culture

Journal of Cellular Physiology ◽

10.1002/(sici)1097-4652(199610)169:1<78::aid-jcp8>3.0.co;2-b ◽

1996 ◽

Vol 169 (1) ◽

pp. 78-86 ◽

Cited By ~ 10

Author(s):

Patrick Michaut ◽

Carole Planes ◽

Brigitte Escoubet ◽

Annick Clement ◽

Claude Amiel ◽

...

Keyword(s):

Primary Culture ◽

Cell Line ◽

Sodium Transport ◽

Alveolar Type ◽

Type Ii ◽

Rat Lung ◽

Alveolar Type Ii Cell ◽

Type Ii Cell

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Zinc modulates mRNA levels of cytokines

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00545.2002 ◽

2003 ◽

Vol 285 (5) ◽

pp. E1095-E1102 ◽

Cited By ~ 120

Author(s):

Bin Bao ◽

Ananda S. Prasad ◽

Frances W. J. Beck ◽

Michele Godmere

Keyword(s):

Gene Expression ◽

Cell Line ◽

Zinc Deficiency ◽

Mrna Levels ◽

Macrophage Cell Line ◽

Macrophage Cell ◽

Th1 Cell ◽

Killer Activity ◽

Tnf Α ◽

Ifn Γ

Zinc plays an important role in cell-mediated immune function. Altered cellular immune response resulting from zinc deficiency leads to frequent microbial infections, thymic atrophy, decreased natural killer activity, decreased thymic hormone activity, and altered cytokine production. In this study, we examined the effect of zinc deficiency on IL-2 and IFN-γ in HUT-78 (Th0) and D1.1 (Th1) cell lines and TNF-α, IL-1β, and IL-8 in the HL-60 (monocyte-macrophage) cell line. The results demonstrate that zinc deficiency decreased the levels of IL-2 and IFN-γ cytokines and mRNAs in HUT-78 after 6 h of PMA/ p-phytohemagglutinin (PHA) stimulation and in D1.1 cells after 6 h of PHA/ionomycin stimulation compared with the zinc-sufficient cells. However, zinc deficiency increased the levels of TNF-α, IL-1β, and IL-8 cytokines and mRNAs in HL-60 cells after 6 h of PMA stimulation compared with zinc-sufficient cells. Actinomycin D study suggests that the changes in the levels of these cytokine mRNAs were not the result of the stability affected by zinc but might be the result of altered expression of these cytokine genes. These data demonstrate that zinc mediates positively the gene expression of IL-2 and IFN-γ in the Th1 cell line and negatively TNF-α, IL-1β, and IL-8 in the monocyte-macrophage cell line. Our study shows that the effect of zinc on gene expression and production of cytokines is cell lineage specific.

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TNF-α increases ceramide without inducing apoptosis in alveolar type II epithelial cells

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1999.276.3.l481 ◽

1999 ◽

Vol 276 (3) ◽

pp. L481-L490 ◽

Cited By ~ 12

Author(s):

Rama K. Mallampalli ◽

Erik J. Peterson ◽

Aaron Brent Carter ◽

Ronald G. Salome ◽

Satya N. Mathur ◽

...

Keyword(s):

Epithelial Cells ◽

Control Level ◽

Nuclear Factor Κb ◽

Mitogen Activated Protein Kinase ◽

Alveolar Type ◽

Type Ii Cells ◽

Nuclear Factor ◽

Type Ii ◽

Tnf Α

Ceramide is a bioactive lipid mediator that has been observed to induce apoptosis in vitro. The purpose of this study was to determine whether endogenous ceramide, generated in response to in vivo administration of tumor necrosis factor-α (TNF-α), increases apoptosis in primary rat alveolar type II epithelial cells. Intratracheal instillation of TNF-α (5 μg) produced a decrease in sphingomyelin and activation of a neutral sphingomyelinase. These changes were associated with a significant increase in lung ceramide content. TNF-α concomitantly activated the p42/44 extracellular signal-related kinases and induced nuclear factor-κB activation in the lung. Hypodiploid nuclei studies revealed that intratracheal TNF-α did not increase type II cell apoptosis compared with that in control cells after isolation. A novel observation from separate in vitro studies demonstrated that type II cells undergo a gradual increase in apoptosis after time in culture, a process that was accelerated by exposure of cells to ultraviolet light. However, culture of cells with a cell-permeable ceramide, TNF-α, or a related ligand, anti-CD95, did not increase apoptosis above the control level. The results suggest that ceramide resulting from TNF-α activation of sphingomyelin hydrolysis might activate the mitogen-activated protein kinase and nuclear factor-κB pathways without increasing programmed cell death in type II cells.

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