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Hyperosmolarity invokes distinct anti-inflammatory mechanisms in pulmonary epithelial cells: evidence from signaling and transcription layers.

Wright FL, Gamboni F, Moore EE, Nydam TL, Mitra S, Silliman CC, Banerjee A - PLoS ONE (2014)

Bottom Line: HTS and sorbitol supplemented media produced comparable outcomes in all experiments, indicating that the effects of HTS were mediated by osmolarity, not by sodium.While not affecting MAPK modules discernibly in A549 cells, both HOsm conditions inhibit IRF-1 against TNFα or IL-1β, but inhibit p65 NF-kB translocation only against TNFα but not IL-1β.Thus, anti-inflammatory mechanisms of HTS/HOsm appear to disrupt cytokine signals at distinct intracellular steps.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery/Trauma Research Center, University of Colorado Denver, Aurora, Colorado, United States of America.

ABSTRACT
Hypertonic saline (HTS) has been used intravenously to reduce organ dysfunction following injury and as an inhaled therapy for cystic fibrosis lung disease. The role and mechanism of HTS inhibition was explored in the TNFα and IL-1β stimulation of pulmonary epithelial cells. Hyperosmolar (HOsm) media (400 mOsm) inhibited the production of select cytokines stimulated by TNFα and IL-1β at the level of mRNA translation, synthesis and release. In TNFα stimulated A549 cells, HOsm media inhibited I-κBα phosphorylation, NF-κB translocation into the nucleus and NF-κB nuclear binding. In IL-1β stimulated cells HOsm inhibited I-κBα phosphorylation without affecting NF-κB translocation or nuclear binding. Incubation in HOsm conditions inhibited both TNFα and IL-1β stimulated nuclear localization of interferon response factor 1 (IRF-1). Additional transcription factors such as AP-1, Erk-1/2, JNK and STAT-1 were unaffected by HOsm. HTS and sorbitol supplemented media produced comparable outcomes in all experiments, indicating that the effects of HTS were mediated by osmolarity, not by sodium. While not affecting MAPK modules discernibly in A549 cells, both HOsm conditions inhibit IRF-1 against TNFα or IL-1β, but inhibit p65 NF-kB translocation only against TNFα but not IL-1β. Thus, anti-inflammatory mechanisms of HTS/HOsm appear to disrupt cytokine signals at distinct intracellular steps.

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Related in: MedlinePlus

HOsm does not significantly affect cell volume.Top left panel shows the mean total cell volume of pulmonary epithelial cells measured by immunofluorescent microscopy is not changed in the presence of 400 mOsm HTS or SOR after 18 hours of incubation (n = 3). The panel on top right shows mean (± sem) forward scatter of pulmonary epithelial cells measured by flow cytometry is also unchanged in the presence of isotonic and 400, 500, and 600 mOsm solutions of media plus HTS, after 18 hours of incubation (n = 3).
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pone-0114129-g007: HOsm does not significantly affect cell volume.Top left panel shows the mean total cell volume of pulmonary epithelial cells measured by immunofluorescent microscopy is not changed in the presence of 400 mOsm HTS or SOR after 18 hours of incubation (n = 3). The panel on top right shows mean (± sem) forward scatter of pulmonary epithelial cells measured by flow cytometry is also unchanged in the presence of isotonic and 400, 500, and 600 mOsm solutions of media plus HTS, after 18 hours of incubation (n = 3).

Mentions: Hyperosmolarity represents a promising potential therapy against inflammation. Both NaCl and sorbitol can be used to prepare hyperosmolar solutions and are clinically accessible. While NaCl is ionized in aqueous solutions, sorbitol is a C6 polyol (an open chain configuration of an hexose). We used these to determine whether the intracellular response to HOsm required ion flux to achieve anti-inflammatory benefit. We and others have used modest hyperosmolarity of about 400 mOsm against various cells [1], [27], [35], [36], [37]. These doses were derived from peak levels achievable in animal models and substantial cell shrinkage or death (Fig 7) are not evident. We have also used inhaled aerosolized hypertonic saline to protect animal lungs but the local dose is unknown [6].


Hyperosmolarity invokes distinct anti-inflammatory mechanisms in pulmonary epithelial cells: evidence from signaling and transcription layers.

Wright FL, Gamboni F, Moore EE, Nydam TL, Mitra S, Silliman CC, Banerjee A - PLoS ONE (2014)

HOsm does not significantly affect cell volume.Top left panel shows the mean total cell volume of pulmonary epithelial cells measured by immunofluorescent microscopy is not changed in the presence of 400 mOsm HTS or SOR after 18 hours of incubation (n = 3). The panel on top right shows mean (± sem) forward scatter of pulmonary epithelial cells measured by flow cytometry is also unchanged in the presence of isotonic and 400, 500, and 600 mOsm solutions of media plus HTS, after 18 hours of incubation (n = 3).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4257597&req=5

pone-0114129-g007: HOsm does not significantly affect cell volume.Top left panel shows the mean total cell volume of pulmonary epithelial cells measured by immunofluorescent microscopy is not changed in the presence of 400 mOsm HTS or SOR after 18 hours of incubation (n = 3). The panel on top right shows mean (± sem) forward scatter of pulmonary epithelial cells measured by flow cytometry is also unchanged in the presence of isotonic and 400, 500, and 600 mOsm solutions of media plus HTS, after 18 hours of incubation (n = 3).
Mentions: Hyperosmolarity represents a promising potential therapy against inflammation. Both NaCl and sorbitol can be used to prepare hyperosmolar solutions and are clinically accessible. While NaCl is ionized in aqueous solutions, sorbitol is a C6 polyol (an open chain configuration of an hexose). We used these to determine whether the intracellular response to HOsm required ion flux to achieve anti-inflammatory benefit. We and others have used modest hyperosmolarity of about 400 mOsm against various cells [1], [27], [35], [36], [37]. These doses were derived from peak levels achievable in animal models and substantial cell shrinkage or death (Fig 7) are not evident. We have also used inhaled aerosolized hypertonic saline to protect animal lungs but the local dose is unknown [6].

Bottom Line: HTS and sorbitol supplemented media produced comparable outcomes in all experiments, indicating that the effects of HTS were mediated by osmolarity, not by sodium.While not affecting MAPK modules discernibly in A549 cells, both HOsm conditions inhibit IRF-1 against TNFα or IL-1β, but inhibit p65 NF-kB translocation only against TNFα but not IL-1β.Thus, anti-inflammatory mechanisms of HTS/HOsm appear to disrupt cytokine signals at distinct intracellular steps.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery/Trauma Research Center, University of Colorado Denver, Aurora, Colorado, United States of America.

ABSTRACT
Hypertonic saline (HTS) has been used intravenously to reduce organ dysfunction following injury and as an inhaled therapy for cystic fibrosis lung disease. The role and mechanism of HTS inhibition was explored in the TNFα and IL-1β stimulation of pulmonary epithelial cells. Hyperosmolar (HOsm) media (400 mOsm) inhibited the production of select cytokines stimulated by TNFα and IL-1β at the level of mRNA translation, synthesis and release. In TNFα stimulated A549 cells, HOsm media inhibited I-κBα phosphorylation, NF-κB translocation into the nucleus and NF-κB nuclear binding. In IL-1β stimulated cells HOsm inhibited I-κBα phosphorylation without affecting NF-κB translocation or nuclear binding. Incubation in HOsm conditions inhibited both TNFα and IL-1β stimulated nuclear localization of interferon response factor 1 (IRF-1). Additional transcription factors such as AP-1, Erk-1/2, JNK and STAT-1 were unaffected by HOsm. HTS and sorbitol supplemented media produced comparable outcomes in all experiments, indicating that the effects of HTS were mediated by osmolarity, not by sodium. While not affecting MAPK modules discernibly in A549 cells, both HOsm conditions inhibit IRF-1 against TNFα or IL-1β, but inhibit p65 NF-kB translocation only against TNFα but not IL-1β. Thus, anti-inflammatory mechanisms of HTS/HOsm appear to disrupt cytokine signals at distinct intracellular steps.

Show MeSH
Related in: MedlinePlus