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Syk phosphorylation – a gravisensitive step in macrophage signalling

BACKGROUND: The recognition of pathogen patterns followed by the production of reactive oxygen species (ROS) during the oxidative burst is one of the major functions of macrophages. This process is the first line of defence and is crucial for the prevention of pathogen-associated diseases. There are...

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Autores principales: Brungs, Sonja, Kolanus, Waldemar, Hemmersbach, Ruth
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4326470/
https://www.ncbi.nlm.nih.gov/pubmed/25644261
http://dx.doi.org/10.1186/s12964-015-0088-8
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author Brungs, Sonja
Kolanus, Waldemar
Hemmersbach, Ruth
author_facet Brungs, Sonja
Kolanus, Waldemar
Hemmersbach, Ruth
author_sort Brungs, Sonja
collection PubMed
description BACKGROUND: The recognition of pathogen patterns followed by the production of reactive oxygen species (ROS) during the oxidative burst is one of the major functions of macrophages. This process is the first line of defence and is crucial for the prevention of pathogen-associated diseases. There are indications that the immune system of astronauts is impaired during spaceflight, which could result in an increased susceptibility to infections. Several studies have indicated that the oxidative burst of macrophages is highly impaired after spaceflight, but the underlying mechanism remained to be elucidated. Here, we investigated the characteristics of reactive oxygen species production during the oxidative burst after pathogen pattern recognition in simulated microgravity by using a fast-rotating Clinostat to mimic the condition of microgravity. Furthermore, spleen tyrosine kinase (Syk) phosphorylation, which is required for ROS production, and the translocation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) to the nucleus were monitored to elucidate the influence of altered gravity on macrophage signalling. RESULTS: Simulated microgravity leads to significantly diminished ROS production in macrophages upon zymosan, curdlan and lipopolysaccharide stimulation. To address the signalling mechanisms involved, Syk phosphorylation was examined, revealing significantly reduced phosphorylation in simulated microgravity compared to normal gravity (1 g) conditions. In contrast, a later signalling step, the translocation of NF-κB to the nucleus, demonstrated no gravity-dependent alterations. CONCLUSIONS: The results obtained in simulated microgravity show that ROS production in macrophages is a highly gravisensitive process, caused by a diminished Syk phosphorylation. In contrast, NF-κB signalling remains consistent in simulated microgravity. This difference reveals that early signalling steps, such as Syk phosphorylation, are affected by microgravity, whereas the lack of effects in later steps might indicate adaptation processes. Taken together, this study clearly demonstrates that macrophages display impaired signalling upon pattern recognition when exposed to simulated microgravity conditions, which if verified in real microgravity this may be one reason why astronauts display higher susceptibility to infections.
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spelling pubmed-43264702015-02-14 Syk phosphorylation – a gravisensitive step in macrophage signalling Brungs, Sonja Kolanus, Waldemar Hemmersbach, Ruth Cell Commun Signal Research BACKGROUND: The recognition of pathogen patterns followed by the production of reactive oxygen species (ROS) during the oxidative burst is one of the major functions of macrophages. This process is the first line of defence and is crucial for the prevention of pathogen-associated diseases. There are indications that the immune system of astronauts is impaired during spaceflight, which could result in an increased susceptibility to infections. Several studies have indicated that the oxidative burst of macrophages is highly impaired after spaceflight, but the underlying mechanism remained to be elucidated. Here, we investigated the characteristics of reactive oxygen species production during the oxidative burst after pathogen pattern recognition in simulated microgravity by using a fast-rotating Clinostat to mimic the condition of microgravity. Furthermore, spleen tyrosine kinase (Syk) phosphorylation, which is required for ROS production, and the translocation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) to the nucleus were monitored to elucidate the influence of altered gravity on macrophage signalling. RESULTS: Simulated microgravity leads to significantly diminished ROS production in macrophages upon zymosan, curdlan and lipopolysaccharide stimulation. To address the signalling mechanisms involved, Syk phosphorylation was examined, revealing significantly reduced phosphorylation in simulated microgravity compared to normal gravity (1 g) conditions. In contrast, a later signalling step, the translocation of NF-κB to the nucleus, demonstrated no gravity-dependent alterations. CONCLUSIONS: The results obtained in simulated microgravity show that ROS production in macrophages is a highly gravisensitive process, caused by a diminished Syk phosphorylation. In contrast, NF-κB signalling remains consistent in simulated microgravity. This difference reveals that early signalling steps, such as Syk phosphorylation, are affected by microgravity, whereas the lack of effects in later steps might indicate adaptation processes. Taken together, this study clearly demonstrates that macrophages display impaired signalling upon pattern recognition when exposed to simulated microgravity conditions, which if verified in real microgravity this may be one reason why astronauts display higher susceptibility to infections. BioMed Central 2015-02-03 /pmc/articles/PMC4326470/ /pubmed/25644261 http://dx.doi.org/10.1186/s12964-015-0088-8 Text en © Brungs et al.; licensee BioMed Central. 2015 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Brungs, Sonja
Kolanus, Waldemar
Hemmersbach, Ruth
Syk phosphorylation – a gravisensitive step in macrophage signalling
title Syk phosphorylation – a gravisensitive step in macrophage signalling
title_full Syk phosphorylation – a gravisensitive step in macrophage signalling
title_fullStr Syk phosphorylation – a gravisensitive step in macrophage signalling
title_full_unstemmed Syk phosphorylation – a gravisensitive step in macrophage signalling
title_short Syk phosphorylation – a gravisensitive step in macrophage signalling
title_sort syk phosphorylation – a gravisensitive step in macrophage signalling
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4326470/
https://www.ncbi.nlm.nih.gov/pubmed/25644261
http://dx.doi.org/10.1186/s12964-015-0088-8
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