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Huang J, Kang W, Yi D, Zhu S, Xiang Y, Liu C, Li H, Dai D, Su J, He J, Liang Z. Intranasal B5 promotes mucosal defence against Actinobacillus pleuropneumoniae via ameliorating early immunosuppression. Virulence 2024; 15:2316459. [PMID: 38378464 PMCID: PMC10880497 DOI: 10.1080/21505594.2024.2316459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 02/04/2024] [Indexed: 02/22/2024] Open
Abstract
Actinobacillus pleuropneumoniae (APP) is an important pathogen of the porcine respiratory disease complex, which leads to huge economic losses worldwide. We previously demonstrated that Pichia pastoris-producing bovine neutrophil β-defensin-5 (B5) could resist the infection by the bovine intracellular pathogen Mycobacterium bovis. In this study, the roles of synthetic B5 in regulating mucosal innate immune response and protecting against extracellular APP infection were further investigated using a mouse model. Results showed that B5 promoted the production of tumour necrosis factor (TNF)-α, interleukin (IL)-1β, and interferon (IFN)-β in macrophages as well as dendritic cells (DC) and enhanced DC maturation in vitro. Importantly, intranasal B5 was safe and conferred effective protection against APP via reducing the bacterial load in lungs and alleviating pulmonary inflammatory damage. Furthermore, in the early stage of APP infection, we found that intranasal B5 up-regulated the secretion of TNF-α, IL-1β, IL-17, and IL-22; enhanced the rapid recruitment of macrophages, neutrophils, and DC; and facilitated the generation of group 3 innate lymphoid cells in lungs. In addition, B5 activated signalling pathways associated with cellular response to IFN-β and activation of innate immune response in APP-challenged lungs. Collectively, B5 via the intranasal route can effectively ameliorate the immune suppression caused by early APP infection and provide protection against APP. The immunization strategy may be applied to animals or human respiratory bacterial infectious diseases. Our findings highlight the potential importance of B5, enhancing mucosal defence against intracellular bacteria like APP which causes early-phase immune suppression.
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Affiliation(s)
- Jingsheng Huang
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Weichao Kang
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Dandan Yi
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Shuxin Zhu
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Yifei Xiang
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Chengzhi Liu
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Han Li
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Dejia Dai
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Jieyu Su
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Jiakang He
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Zhengmin Liang
- College of Animal Science and Technology, Guangxi University, Nanning, China
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Wang J, Gan L, Li F, Li Q, Wu T, Wu Z, Chen P, Scicluna BP, Feng X, Gu J, Han W, Li N, Lei L. Tracheal epithelial cell-exosome-derived MiR-21-5p inhibits alveolar macrophage pyroptosis to resist pulmonary bacterial infection through PIK3CD-autophagy pathway. Life Sci 2024; 336:122340. [PMID: 38092143 DOI: 10.1016/j.lfs.2023.122340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 06/06/2023] [Accepted: 12/06/2023] [Indexed: 12/24/2023]
Abstract
AIMS Structural cells play an important role in regulating immune cells during infection. Our aim was to determine whether structural porcine tracheal epithelial cells (PTECs) can regulate alveolar macrophages (AMs) to prevent bacterial pneumonia, explore the underlying mechanism(s) and therapeutic target. MATERIALS AND METHODS Actinobacillus pleuropneumoniae (APP) was used as the model strain for infection studies. Small RNA sequencing was used to identify differentially abundant exosome-derived miRNAs. The role of PTECs exosome-derived miR-21-5p in regulating AMs autophagy, pyroptosis, reactive oxygen species (ROS) was determined using RT-qPCR, western-blotting, flow cytometry, immunohistochemistry. Luciferase reporter assays were conducted to identify potential binding targets of miR-21-5p. The universality of miR-21-5p action on resistance to bacterial pulmonary infection was demonstrated using Klebsiella pneumoniae or Staphylococcus aureus in vitro and in vivo infection models. KEY FINDINGS MiR-21-5p was enriched in PETCs-derived exosomes, which protected AMs against pulmonary bacterial infection. Mechanistically, miR-21-5p targeted PIK3CD, to promote autophagy of AMs, which reduced the pyroptosis induced by APP infection via inhibiting the over-production of ROS, which in turn suppressed the over-expression of pro-inflammatory cytokines, and increased bacterial clearance. Importantly, the protective effect and mechanism of miR-21-5p were universal as they also occurred upon challenge with Klebsiella pneumoniae and Staphylococcus aureus. SIGNIFICANCE Our data reveals miR-21-5p can promote pulmonary resistance to bacterial infection by inhibiting pyroptosis of alveolar macrophages through the PIK3CD-autophagy-ROS pathway, suggesting PIK3CD may be a potential therapeutic target for bacterial pneumonia.
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Affiliation(s)
- Jun Wang
- State Key Laboratory for Zoonotic Diseases, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Lin Gan
- State Key Laboratory for Zoonotic Diseases, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Fengyang Li
- State Key Laboratory for Zoonotic Diseases, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Qin Li
- State Key Laboratory for Zoonotic Diseases, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Tong Wu
- State Key Laboratory for Zoonotic Diseases, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Zengshuai Wu
- State Key Laboratory for Zoonotic Diseases, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Peiru Chen
- State Key Laboratory for Zoonotic Diseases, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Brendon P Scicluna
- Department of Applied Biomedical Science, Faculty of Health Sciences, Mater Dei Hospital, University of Malta, Msida, Malta; Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Xin Feng
- State Key Laboratory for Zoonotic Diseases, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Jingmin Gu
- State Key Laboratory for Zoonotic Diseases, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Wenyu Han
- State Key Laboratory for Zoonotic Diseases, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Na Li
- State Key Laboratory for Zoonotic Diseases, College of Veterinary Medicine, Jilin University, Changchun, China.
| | - Liancheng Lei
- State Key Laboratory for Zoonotic Diseases, College of Veterinary Medicine, Jilin University, Changchun, China.
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Zhu J, Zhu R, Jiang H, Li Z, Jiang X, Li F, Zhang F, Feng X, Gu J, Li N, Lei L. Adh Promotes Actinobacillus pleuropneumoniae Survival in Porcine Alveolar Macrophages by Inhibiting CHAC2-Mediated Respiratory Burst and Inflammatory Cytokine Expression. Cells 2023; 12:cells12050696. [PMID: 36899832 PMCID: PMC10001268 DOI: 10.3390/cells12050696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/30/2023] [Accepted: 02/14/2023] [Indexed: 02/25/2023] Open
Abstract
Actinobacillus pleuropneumoniae (A. pleuropneumoniae) causes porcine pleuropneumonia that seriously endangers pig's health. Adh, located in the head region of trimeric autotransporter adhesion of A. pleuropneumoniae, affects bacterial adhesion and pathogenicity. However, how Adh mediates A. pleuropneumoniae immune invasion is still unclear. Here, we established the A. pleuropneumoniae strain L20 or L20 ΔAdh-infected porcine alveolar macrophages (PAM) model, and applied protein overexpression, RNA interference, qRT-PCR, Western blot and immunoflourescence techniques to dissect the effects of Adh on PAM during A. pleuropneumoniae infection. We found that Adh could increase the A. pleuropneumoniae adhesion and intracellular survival in PAM. Gene chip analysis of piglet lungs further showed that Adh significantly induced cation transport regulatory-like protein 2 (CHAC2) expression, whose overexpression suppressed the phagocytic capacity of PAM. Furthermore, CHAC2 overexpression dramatically increased glutathione (GSH) expression, decreased reactive oxygen species (ROS), and promoted A. pleuropneumoniae survival in PAM, while the knockdown of CHAC2 reversed these phenomena. Meanwhile, CHAC2 silence activated the NOD1/NF-κB pathway, resulting in an increase in IL-1β, IL-6, and TNF-α expression, whereas this effect was weakened by CHAC2 overexpression and addition of NOD1/NF-κB inhibitor ML130. Moreover, Adh enhanced the secretion of LPS of A. pleuropneumoniae, which regulated the expression of CHAC2 via TLR4. In conclusion, through a LPS-TLR4-CHAC2 pathway, Adh inhibits respiratory burst and inflammatory cytokines expression to promote A. pleuropneumoniae survival in PAM. This finding may provide a novel target for the prevention and treatment of A. pleuropneumoniae.
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Affiliation(s)
- Junhui Zhu
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Rining Zhu
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Hexiang Jiang
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Ziheng Li
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Xuan Jiang
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Fengyang Li
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Fuxian Zhang
- College of Animal Science, Yangtze University, Jingzhou 434025, China
| | - Xin Feng
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Jingmin Gu
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Na Li
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
- Correspondence: (N.L.); (L.L.)
| | - Liancheng Lei
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
- College of Animal Science, Yangtze University, Jingzhou 434025, China
- Correspondence: (N.L.); (L.L.)
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Assavacheep P, Thanawongnuwech R. Porcine respiratory disease complex: Dynamics of polymicrobial infections and management strategies after the introduction of the African swine fever. Front Vet Sci 2022; 9:1048861. [PMID: 36504860 PMCID: PMC9732666 DOI: 10.3389/fvets.2022.1048861] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 11/14/2022] [Indexed: 11/27/2022] Open
Abstract
A few decades ago, porcine respiratory disease complex (PRDC) exerted a major economic impact on the global swine industry, particularly due to the adoption of intensive farming by the latter during the 1980's. Since then, the emerging of porcine reproductive and respiratory syndrome virus (PRRSV) and of porcine circovirus type 2 (PCV2) as major immunosuppressive viruses led to an interaction with other endemic pathogens (e.g., Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, Streptococcus suis, etc.) in swine farms, thereby exacerbating the endemic clinical diseases. We herein, review and discuss various dynamic polymicrobial infections among selected swine pathogens. Traditional biosecurity management strategies through multisite production, parity segregation, batch production, the adoption of all-in all-out production systems, specific vaccination and medication protocols for the prevention and control (or even eradication) of swine diseases are also recommended. After the introduction of the African swine fever (ASF), particularly in Asian countries, new normal management strategies minimizing pig contact by employing automatic feeding systems, artificial intelligence, and robotic farming and reducing the numbers of vaccines are suggested. Re-emergence of existing swine pathogens such as PRRSV or PCV2, or elimination of some pathogens may occur after the ASF-induced depopulation. ASF-associated repopulating strategies are, therefore, essential for the establishment of food security. The "repopulate swine farm" policy and the strict biosecurity management (without the use of ASF vaccines) are, herein, discussed for the sustainable management of small-to-medium pig farms, as these happen to be the most potential sources of an ASF re-occurrence. Finally, the ASF disruption has caused the swine industry to rapidly transform itself. Artificial intelligence and smart farming have gained tremendous attention as promising tools capable of resolving challenges in intensive swine farming and enhancing the farms' productivity and efficiency without compromising the strict biosecurity required during the ongoing ASF era.
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Affiliation(s)
- Pornchalit Assavacheep
- Department of Veterinary Medicine, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand,*Correspondence: Pornchalit Assavacheep
| | - Roongroje Thanawongnuwech
- Department of Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand,Faculty of Veterinary Science, Center of Emerging and Re-emerging Infectious Diseases in Animals, Chulalongkorn University, Bangkok, Thailand,Roongroje Thanawongnuwech
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5
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Severe Inflammation Caused by Coinfection of PCV2 and Glaesserella parasuis Is Associated with Pyroptosis via Noncanonical Inflammasome Pathway. Cell Microbiol 2022. [DOI: 10.1155/2022/7227099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Coinfections of porcine circovirus type 2 (PCV2) and Glaesserella parasuis (G. parasuis) are widely existing in the swine industry worldwide. However, the mechanisms for this coinfection remain unclear. The aim of this study is to assess whether the coinfection PCV2 and G. parasuis would affect the inflammatory response and related mechanisms. In this study, BALB/c mice and RAW264.7 cells were used to study the inflammation and related mechanism caused by the coinfection of PCV2 and G. parasuis. Coinfection with PCV2 and G. parasuis significantly increased the mortality of mice and led to the development of more severe lung and spleen lesions compared with single agent infection. Especially, coinfection significantly increased the bacterial loads in the lungs. Coinfection with PCV2 and G. parasuis can enhance RAW264.7 cell phagocytosis and elimination to G. parasuis. Cell death rate of cells increased in coinfection was measured with Flow cytometry. Moreover, coinfection led to the downregulation of the expression of TNFα and IL-8 in comparison with G. parasuis infection, but the maturation of interleukin-1β (IL-1β) was significantly upregulated. Our study firstly revealed that coinfection of PCV2 and G. parasuis can increase the phagocytosis of cells to G. parasuis, and LPS in the cytoplasm will induce the maturation of caspase-11 and lead to the cleavage of Gasdermin D (GSDMD) to cause pyroptosis by noncanonical pathway. The revealing of mechanisms associated with coinfection with PCV2 and G. parasuis will provide a scientific basis for investigating the synergistic infection mechanisms between viruses and bacteria.
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Hennig-Pauka I, Hartmann M, Merkel J, Kreienbrock L. Coinfections and Phenotypic Antimicrobial Resistance in Actinobacillus pleuropneumoniae Strains Isolated From Diseased Swine in North Western Germany-Temporal Patterns in Samples From Routine Laboratory Practice From 2006 to 2020. Front Vet Sci 2022; 8:802570. [PMID: 35155648 PMCID: PMC8831912 DOI: 10.3389/fvets.2021.802570] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 12/14/2021] [Indexed: 11/13/2022] Open
Abstract
Actinobacillus pleuropneumoniae (APP) is one major bacterial porcine respiratory tract pathogen causing disease outbreaks worldwide, although effective commercial vaccines are available. Due to frequent failure of this preventive measure, treatment with antimicrobials is indispensable to prevent animal losses within an outbreak situation. To preserve the effectivity of antimicrobial substances to fight APP should therefore be the primary aim of any interventions. In this study, the temporal development of antimicrobial resistance in APP was analyzed retrospectively in the time period 2006-2020 from a routine diagnostic database. In parallel, frequent coinfections were evaluated to identify most important biotic cofactors as important triggers for disease outbreaks in endemically infected herds. The proportion of APP serotype 2 decreased over time but was isolated most often from diseased swine (57% in 2020). In ~1% of the cases, APP was isolated from body sites outside the respiratory tract as brain and joints. The lowest frequencies of resistant isolates were found for cephalothin and ceftiofur (0.18%), florfenicol (0.24%), tilmicosin (2.4%), tiamulin (2.4%), enrofloxacin (2.7%), and spectinomycin (3.6%), while the highest frequencies of resistant isolates were found for gentamicin (30.9%), penicillin (51.5%), and tetracycline (78.2%). For enrofloxacin, tiamulin, tilmicosin, and tetracycline, significantly lower frequencies of resistant isolates were found in the time period 2015-2020 compared to 2006-2014, while gentamicin-resistant isolates increased. In summary, there is only a low risk of treatment failure due to resistant isolates. In maximum, up to six coinfecting pathogens were identified in pigs positive for APP. Most often pigs were coinfected with Porcine Circovirus 2 (56%), Streptococcus suis (24.8%), or the Porcine Reproductive and Respiratory Syndrome Virus (23.3%). Potential synergistic effects between these pathogens published from experimental findings can be hypothesized by these field data as well. To prevent APP disease outbreaks in endemically infected herds more efficiently in the future, next to environmental trigger factors, preventive measures must also address the coinfecting agents.
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Affiliation(s)
- Isabel Hennig-Pauka
- Field Station for Epidemiology, University of Veterinary Medicine Hannover, Bakum, Germany
| | - Maria Hartmann
- Department of Biometry, Epidemiology and Information Processing, WHO Collaborating Centre for Research and Training for Health at the Human-Animal-Environment Interface, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Jörg Merkel
- Department of Infectious Diseases, Institute for Microbiology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Lothar Kreienbrock
- Department of Biometry, Epidemiology and Information Processing, WHO Collaborating Centre for Research and Training for Health at the Human-Animal-Environment Interface, University of Veterinary Medicine Hannover, Hannover, Germany
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7
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Zhang W, Fu Z, Yin H, Han Q, Fan W, Wang F, Shang Y. Macrophage Polarization Modulated by Porcine Circovirus Type 2 Facilitates Bacterial Coinfection. Front Immunol 2021; 12:688294. [PMID: 34394082 PMCID: PMC8355693 DOI: 10.3389/fimmu.2021.688294] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/12/2021] [Indexed: 12/13/2022] Open
Abstract
Polarization of macrophages to different functional states is important for mounting responses against pathogen infections. Macrophages are the major target cells of porcine circovirus type 2 (PCV2), which is the primary causative agent of porcine circovirus-associated disease (PCVAD) leading to immense economic losses in the global swine industry. Clinically, PCV2 is often found to increase risk of other pathogenic infections yet the underlying mechanisms remain to be elusive. Here we found that PCV2 infection skewed macrophages toward a M1 status through reprogramming expression of a subset of M1-associated genes and M2-associated genes. Mechanistically, induction of M1-associated genes by PCV2 infection is dependent on activation of nuclear factor kappa B (NF-κB) and c-jun N-terminal kinase (JNK) signaling pathways whereas suppression of M2-associated genes by PCV2 is via inhibiting expression of jumonji domain containing-3 (JMJD3), a histone 3 Lys27 (H3K27) demethylase that regulates M2 activation of macrophages. Finally, we identified that PCV2 capsid protein (Cap) directly inhibits JMJD3 transcription to restrain expression of interferon regulatory factor (IRF4) that controls M2 macrophage polarization. Consequently, sustained infection of PCV2 facilitates bacterial infection in vitro. In summary, these findings showed that PCV2 infection functionally modulated M1 macrophage polarization via targeting canonical signals and epigenetic histone modification, which contributes to bacterial coinfection and virial pathogenesis.
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Affiliation(s)
- Wen Zhang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, China
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian, China
| | - Zhendong Fu
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, China
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian, China
| | - Hongyan Yin
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, China
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian, China
| | - Qingbing Han
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, China
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian, China
| | - Wenhui Fan
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Fangkun Wang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, China
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian, China
- Institute of Immunology, Shandong Agricultural University, Taian, China
| | - Yingli Shang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, China
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian, China
- Institute of Immunology, Shandong Agricultural University, Taian, China
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Nahar N, Turni C, Tram G, Blackall PJ, Atack JM. Actinobacillus pleuropneumoniae: The molecular determinants of virulence and pathogenesis. Adv Microb Physiol 2021; 78:179-216. [PMID: 34147185 DOI: 10.1016/bs.ampbs.2020.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, is responsible for high economic losses in swine herds across the globe. Pleuropneumonia is characterized by severe respiratory distress and high mortality. The knowledge about the interaction between bacterium and host within the porcine respiratory tract has improved significantly in recent years. A. pleuropneumoniae expresses multiple virulence factors, which are required for colonization, immune clearance, and tissue damage. Although vaccines are used to protect swine herds against A. pleuropneumoniae infection, they do not offer complete coverage, and often only protect against the serovar, or serovars, used to prepare the vaccine. This review will summarize the role of individual A. pleuropneumoniae virulence factors that are required during key stages of pathogenesis and disease progression, and highlight progress made toward developing effective and broadly protective vaccines against an organism of great importance to global agriculture and food production.
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Affiliation(s)
- Nusrat Nahar
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia
| | - Conny Turni
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD, Australia
| | - Greg Tram
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia
| | - Patrick J Blackall
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD, Australia.
| | - John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia.
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Coinfection with Porcine Circovirus Type 2 (PCV2) and Streptococcus suis Serotype 2 (SS2) Enhances the Survival of SS2 in Swine Tracheal Epithelial Cells by Decreasing Reactive Oxygen Species Production. Infect Immun 2020; 88:IAI.00537-20. [PMID: 32868342 DOI: 10.1128/iai.00537-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 12/11/2022] Open
Abstract
Porcine circovirus type 2 (PCV2) and Streptococcus suis serotype 2 (SS2) clinical coinfection cases have been frequently detected. The respiratory epithelium plays a crucial role in host defense against a variety of inhaled pathogens. Reactive oxygen species (ROS) are involved in killing of bacteria and host immune response. The aim of this study is to assess whether PCV2 and SS2 coinfection in swine tracheal epithelial cells (STEC) affects ROS production and investigate the roles of ROS in bacterial survival and the inflammatory response. Compared to SS2 infection, PCV2/SS2 coinfection inhibited the activity of NADPH oxidase, resulting in lower ROS levels. Bacterial intracellular survival experiments showed that coinfection with PCV2 and SS2 enhanced SS2 survival in STEC. Pretreatment of STEC with N-acetylcysteine (NAC) also helps SS2 intracellular survival, indicating that PCV2/SS2 coinfection enhances the survival of SS2 in STEC through a decrease in ROS production. In addition, compared to SS2-infected STEC, PCV2/SS2 coinfection and pretreatment of STEC with NAC prior to SS2 infection both downregulated the expression of the inflammatory cytokines interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and IL-1β. Further research found that activation of p38/MAPK promoted the expression of inflammatory cytokines in SS2-infected STEC; however, PCV2/SS2 coinfection or NAC pretreatment of STEC inhibited p38 phosphorylation, suggesting that coinfection of STEC with PCV2 and SS2 weakens the inflammatory response to SS2 infection through reduced ROS production. Collectively, coinfection of STEC with PCV2 and SS2 enhances the intracellular survival of SS2 and weakens the inflammatory response through decreased ROS production, which might exacerbate SS2 infection in the host.
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Coinfections and their molecular consequences in the porcine respiratory tract. Vet Res 2020; 51:80. [PMID: 32546263 PMCID: PMC7296899 DOI: 10.1186/s13567-020-00807-8] [Citation(s) in RCA: 114] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 06/02/2020] [Indexed: 01/15/2023] Open
Abstract
Understudied, coinfections are more frequent in pig farms than single infections. In pigs, the term “Porcine Respiratory Disease Complex” (PRDC) is often used to describe coinfections involving viruses such as swine Influenza A Virus (swIAV), Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), and Porcine CircoVirus type 2 (PCV2) as well as bacteria like Actinobacillus pleuropneumoniae, Mycoplasma hyopneumoniae and Bordetella bronchiseptica. The clinical outcome of the various coinfection or superinfection situations is usually assessed in the studies while in most of cases there is no clear elucidation of the fine mechanisms shaping the complex interactions occurring between microorganisms. In this comprehensive review, we aimed at identifying the studies dealing with coinfections or superinfections in the pig respiratory tract and at presenting the interactions between pathogens and, when possible, the mechanisms controlling them. Coinfections and superinfections involving viruses and bacteria were considered while research articles including protozoan and fungi were excluded. We discuss the main limitations complicating the interpretation of coinfection/superinfection studies, and the high potential perspectives in this fascinating research field, which is expecting to gain more and more interest in the next years for the obvious benefit of animal health.
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