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Intracellular behavior of Nocardia seriolae and its apoptotic effect on RAW264.7 macrophages

Nocardia seriolae, an intracellular gram-positive pathogen, is prone to infecting immunocompromised and surface-damaged fish, causing serious losses to the aquaculture industry. Although a previous study has demonstrated that N. seriolae infects macrophages, the persistence of this bacterium in macr...

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Autores principales: Liu, Wenwen, Deng, Yuting, Tan, Aiping, Zhao, Fei, Chang, Ouqing, Wang, Fang, Lai, Yingtiao, Huang, Zhibin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10011490/
https://www.ncbi.nlm.nih.gov/pubmed/36926518
http://dx.doi.org/10.3389/fcimb.2023.1138422
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author Liu, Wenwen
Deng, Yuting
Tan, Aiping
Zhao, Fei
Chang, Ouqing
Wang, Fang
Lai, Yingtiao
Huang, Zhibin
author_facet Liu, Wenwen
Deng, Yuting
Tan, Aiping
Zhao, Fei
Chang, Ouqing
Wang, Fang
Lai, Yingtiao
Huang, Zhibin
author_sort Liu, Wenwen
collection PubMed
description Nocardia seriolae, an intracellular gram-positive pathogen, is prone to infecting immunocompromised and surface-damaged fish, causing serious losses to the aquaculture industry. Although a previous study has demonstrated that N. seriolae infects macrophages, the persistence of this bacterium in macrophages has not been well characterized. To address this gap, we used the macrophage cell line RAW264.7, to investigate the interactions between N. seriolae and macrophages and deciphered the intracellular survival mechanism of N. seriolae. Confocal and light microscopy revealed that N. seriolae entered macrophages 2 hours post-inoculation (hpi), were phagocytosed by macrophages at 4–8 hpi, and induced the formation of multinucleated macrophages by severe fusion at 12 hpi. Flow cytometry, evaluation of mitochondrial membrane potential, release of lactate dehydrogenase, and observation of the ultrastructure of macrophages revealed that apoptosis was induced in the early infection stage and inhibited in the middle and later periods of infection. Additionally, the expression of Bcl-2, Bax, Cyto-C, Caspase-3, Capase-8, and Caspase-9 was induced at 4 hpi, and then decreased at 6–8 hpi, illustrating that N. seriolae infection induces the activation of extrinsic and intrinsic apoptotic pathways in macrophages, followed by the inhibition of apoptosis to survive inside the cells. Furthermore, N. seriolae inhibits the production of reactive oxygen species and releases large amounts of nitric oxide, which persists in macrophages during infection. The present study provides the first comprehensive insight into the intracellular behavior of N. seriolae and its apoptotic effect on macrophages and may be important for understanding the pathogenicity of fish nocardiosis.
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spelling pubmed-100114902023-03-15 Intracellular behavior of Nocardia seriolae and its apoptotic effect on RAW264.7 macrophages Liu, Wenwen Deng, Yuting Tan, Aiping Zhao, Fei Chang, Ouqing Wang, Fang Lai, Yingtiao Huang, Zhibin Front Cell Infect Microbiol Cellular and Infection Microbiology Nocardia seriolae, an intracellular gram-positive pathogen, is prone to infecting immunocompromised and surface-damaged fish, causing serious losses to the aquaculture industry. Although a previous study has demonstrated that N. seriolae infects macrophages, the persistence of this bacterium in macrophages has not been well characterized. To address this gap, we used the macrophage cell line RAW264.7, to investigate the interactions between N. seriolae and macrophages and deciphered the intracellular survival mechanism of N. seriolae. Confocal and light microscopy revealed that N. seriolae entered macrophages 2 hours post-inoculation (hpi), were phagocytosed by macrophages at 4–8 hpi, and induced the formation of multinucleated macrophages by severe fusion at 12 hpi. Flow cytometry, evaluation of mitochondrial membrane potential, release of lactate dehydrogenase, and observation of the ultrastructure of macrophages revealed that apoptosis was induced in the early infection stage and inhibited in the middle and later periods of infection. Additionally, the expression of Bcl-2, Bax, Cyto-C, Caspase-3, Capase-8, and Caspase-9 was induced at 4 hpi, and then decreased at 6–8 hpi, illustrating that N. seriolae infection induces the activation of extrinsic and intrinsic apoptotic pathways in macrophages, followed by the inhibition of apoptosis to survive inside the cells. Furthermore, N. seriolae inhibits the production of reactive oxygen species and releases large amounts of nitric oxide, which persists in macrophages during infection. The present study provides the first comprehensive insight into the intracellular behavior of N. seriolae and its apoptotic effect on macrophages and may be important for understanding the pathogenicity of fish nocardiosis. Frontiers Media S.A. 2023-02-28 /pmc/articles/PMC10011490/ /pubmed/36926518 http://dx.doi.org/10.3389/fcimb.2023.1138422 Text en Copyright © 2023 Liu, Deng, Tan, Zhao, Chang, Wang, Lai and Huang 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.
spellingShingle Cellular and Infection Microbiology
Liu, Wenwen
Deng, Yuting
Tan, Aiping
Zhao, Fei
Chang, Ouqing
Wang, Fang
Lai, Yingtiao
Huang, Zhibin
Intracellular behavior of Nocardia seriolae and its apoptotic effect on RAW264.7 macrophages
title Intracellular behavior of Nocardia seriolae and its apoptotic effect on RAW264.7 macrophages
title_full Intracellular behavior of Nocardia seriolae and its apoptotic effect on RAW264.7 macrophages
title_fullStr Intracellular behavior of Nocardia seriolae and its apoptotic effect on RAW264.7 macrophages
title_full_unstemmed Intracellular behavior of Nocardia seriolae and its apoptotic effect on RAW264.7 macrophages
title_short Intracellular behavior of Nocardia seriolae and its apoptotic effect on RAW264.7 macrophages
title_sort intracellular behavior of nocardia seriolae and its apoptotic effect on raw264.7 macrophages
topic Cellular and Infection Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10011490/
https://www.ncbi.nlm.nih.gov/pubmed/36926518
http://dx.doi.org/10.3389/fcimb.2023.1138422
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