PRV-1 Infected Macrophages in Melanized Focal Changes in White Muscle of Atlantic Salmon (Salmo salar) Correlates With a Pro-Inflammatory Environment
Melanized focal changes in white skeletal muscle of farmed Atlantic salmon, “black spots”, is a quality problem affecting on average 20% of slaughtered fish. The spots appear initially as “red spots” characterized by hemorrhages and acute inflammation and progress into black spots characterized by c...
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ftpubmed:oai:pubmedcentral.nih.gov:8116804 2023-05-15T15:31:53+02:00 PRV-1 Infected Macrophages in Melanized Focal Changes in White Muscle of Atlantic Salmon (Salmo salar) Correlates With a Pro-Inflammatory Environment Malik, Muhammad Salman Bjørgen, Håvard Nyman, Ingvild Berg Wessel, Øystein Koppang, Erling Olaf Dahle, Maria K. Rimstad, Espen 2021-04-29 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8116804/ https://doi.org/10.3389/fimmu.2021.664624 en eng Frontiers Media S.A. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8116804/ http://dx.doi.org/10.3389/fimmu.2021.664624 Copyright © 2021 Malik, Bjørgen, Nyman, Wessel, Koppang, Dahle and Rimstad https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. CC-BY Front Immunol Immunology Text 2021 ftpubmed https://doi.org/10.3389/fimmu.2021.664624 2021-05-16T00:51:50Z Melanized focal changes in white skeletal muscle of farmed Atlantic salmon, “black spots”, is a quality problem affecting on average 20% of slaughtered fish. The spots appear initially as “red spots” characterized by hemorrhages and acute inflammation and progress into black spots characterized by chronic inflammation and abundant pigmented cells. Piscine orthoreovirus 1 (PRV-1) was previously found to be associated with macrophages and melano-macrophages in red and black spots. Here we have addressed the inflammatory microenvironment of red and black spots by studying the polarization status of the macrophages and cell mediated immune responses in spots, in both PRV-1 infected and non-infected fish. Samples that had been collected at regular intervals through the seawater production phase in a commercial farm were analyzed by multiplex fluorescent in situ hybridization (FISH) and RT-qPCR methods. Detection of abundant inducible nitric oxide synthase (iNOS2) expressing M1-polarized macrophages in red spots demonstrated a pro-inflammatory microenvironment. There was an almost perfect co-localization with the iNOS2 expression and PRV-1 infection. Black spots, on the other side, had few iNOS2 expressing cells, but a relatively high number of arginase-2 expressing anti-inflammatory M2-polarized macrophages containing melanin. The numerous M2-polarized melano-macrophages in black spots indicate an ongoing healing phase. Co-localization of PRV-1 and cells expressing CD8(+) and MHC-I suggests a targeted immune response taking place in the spots. Altogether, this study indicates that PRV-1 induces a pro-inflammatory environment that is important for the pathogenesis of the spots. We do not have indication that infection of PRV-1 is the initial causative agent of this condition. Text Atlantic salmon Salmo salar PubMed Central (PMC) Frontiers in Immunology 12 |
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Immunology Malik, Muhammad Salman Bjørgen, Håvard Nyman, Ingvild Berg Wessel, Øystein Koppang, Erling Olaf Dahle, Maria K. Rimstad, Espen PRV-1 Infected Macrophages in Melanized Focal Changes in White Muscle of Atlantic Salmon (Salmo salar) Correlates With a Pro-Inflammatory Environment |
topic_facet |
Immunology |
description |
Melanized focal changes in white skeletal muscle of farmed Atlantic salmon, “black spots”, is a quality problem affecting on average 20% of slaughtered fish. The spots appear initially as “red spots” characterized by hemorrhages and acute inflammation and progress into black spots characterized by chronic inflammation and abundant pigmented cells. Piscine orthoreovirus 1 (PRV-1) was previously found to be associated with macrophages and melano-macrophages in red and black spots. Here we have addressed the inflammatory microenvironment of red and black spots by studying the polarization status of the macrophages and cell mediated immune responses in spots, in both PRV-1 infected and non-infected fish. Samples that had been collected at regular intervals through the seawater production phase in a commercial farm were analyzed by multiplex fluorescent in situ hybridization (FISH) and RT-qPCR methods. Detection of abundant inducible nitric oxide synthase (iNOS2) expressing M1-polarized macrophages in red spots demonstrated a pro-inflammatory microenvironment. There was an almost perfect co-localization with the iNOS2 expression and PRV-1 infection. Black spots, on the other side, had few iNOS2 expressing cells, but a relatively high number of arginase-2 expressing anti-inflammatory M2-polarized macrophages containing melanin. The numerous M2-polarized melano-macrophages in black spots indicate an ongoing healing phase. Co-localization of PRV-1 and cells expressing CD8(+) and MHC-I suggests a targeted immune response taking place in the spots. Altogether, this study indicates that PRV-1 induces a pro-inflammatory environment that is important for the pathogenesis of the spots. We do not have indication that infection of PRV-1 is the initial causative agent of this condition. |
format |
Text |
author |
Malik, Muhammad Salman Bjørgen, Håvard Nyman, Ingvild Berg Wessel, Øystein Koppang, Erling Olaf Dahle, Maria K. Rimstad, Espen |
author_facet |
Malik, Muhammad Salman Bjørgen, Håvard Nyman, Ingvild Berg Wessel, Øystein Koppang, Erling Olaf Dahle, Maria K. Rimstad, Espen |
author_sort |
Malik, Muhammad Salman |
title |
PRV-1 Infected Macrophages in Melanized Focal Changes in White Muscle of Atlantic Salmon (Salmo salar) Correlates With a Pro-Inflammatory Environment |
title_short |
PRV-1 Infected Macrophages in Melanized Focal Changes in White Muscle of Atlantic Salmon (Salmo salar) Correlates With a Pro-Inflammatory Environment |
title_full |
PRV-1 Infected Macrophages in Melanized Focal Changes in White Muscle of Atlantic Salmon (Salmo salar) Correlates With a Pro-Inflammatory Environment |
title_fullStr |
PRV-1 Infected Macrophages in Melanized Focal Changes in White Muscle of Atlantic Salmon (Salmo salar) Correlates With a Pro-Inflammatory Environment |
title_full_unstemmed |
PRV-1 Infected Macrophages in Melanized Focal Changes in White Muscle of Atlantic Salmon (Salmo salar) Correlates With a Pro-Inflammatory Environment |
title_sort |
prv-1 infected macrophages in melanized focal changes in white muscle of atlantic salmon (salmo salar) correlates with a pro-inflammatory environment |
publisher |
Frontiers Media S.A. |
publishDate |
2021 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8116804/ https://doi.org/10.3389/fimmu.2021.664624 |
genre |
Atlantic salmon Salmo salar |
genre_facet |
Atlantic salmon Salmo salar |
op_source |
Front Immunol |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8116804/ http://dx.doi.org/10.3389/fimmu.2021.664624 |
op_rights |
Copyright © 2021 Malik, Bjørgen, Nyman, Wessel, Koppang, Dahle and Rimstad https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.3389/fimmu.2021.664624 |
container_title |
Frontiers in Immunology |
container_volume |
12 |
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