OxyR of Haemophilus parasuis is a global transcriptional regulator important in oxidative stress resistance and growth

Wen, Yongping; Wen, Yiping; Wen, Xintian; Cao, Sanjie; Huang, Xiaobo; Wu, Rui; Zhao, Qin; Liu, Mafeng; Huang, Yong; Yan, Qigui; Han, Xinfeng; Ma, Xiaoping; Dai, Ke; Ding, Lingqiang; Liu, Sitong; Yang, Jian

doi:10.1016/j.gene.2017.12.010

Cited by 13 publications

(10 citation statements)

References 55 publications

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“…The luminol-amplified chemiluminescence is able to detect superoxide anion as well as hydrogen peroxide in the presence of peroxidases ( 28 ). Because decomposition of these reactive oxygen species is catalyzed by the superoxide dismutase and catalase, these two enzymes apparently play an important role in the oxidative stress resistance of G. parasuis observed in our study as well as by other authors ( 20 , 29 , 30 ). Moreover, catalase was identified among the secreted proteins of G. parasuis Nagasaki strain as immunoreactive with G. parasuis anti-Nagasaki convalescent sera ( 31 ).…”

Section: Discussionsupporting

confidence: 79%

The Role of Antibodies Against the Crude Capsular Extract in the Immune Response of Porcine Alveolar Macrophages to In Vitro Infection of Various Serovars of Glaesserella (Haemophilus) parasuis

et al. 2021

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In Glässer’s disease outbreaks, Glaesserella (Haemophilus) parasuis has to overcome the non-specific immune system in the lower respiratory tract, the alveolar macrophages. Here we showed that porcine alveolar macrophages (PAMs) were able to recognize and phagocyte G. parasuis with strain-to-strain variability despite the presence of the capsule in virulent (serovar 1, 5, 12) as well in avirulent strains (serovar 6 and 9). The capsule, outer membrane proteins, virulence-associated autotransporters, cytolethal distending toxins and many other proteins have been identified as virulence factors of this bacterium. Therefore, we immunized pigs with the crude capsular extract (cCE) from the virulent G. parasuis CAPM 6475 strain (serovar 5) and evaluated the role of the anti-cCE/post-vaccinal IgG in the immune response of PAMs to in vitro infection with various G. parasuis strains. We demonstrated the specific binding of the antibodies to the cCE by Western-blotting assay and immunoprecipitation as well as the specific binding to the strain CAPM 6475 in transmission electron microscopy. In the cCE, we identified several virulence-associated proteins that were immunoreactive with IgG isolated from sera of immunized pigs. Opsonization of G. parasuis strains by post-vaccinal IgG led to enhanced phagocytosis of G. parasuis by PAMs at the first two hours of infection. Moreover, opsonization increased the oxidative burst and expression/production of both pro- and anti-inflammatory cytokines. The neutralizing effects of these antibodies on the antioxidant mechanisms of G. parasuis may lead to attenuation of its virulence and pathogenicity in vivo. Together with opsonization of bacteria by these antibodies, the host may eliminate G. parasuis in the infection site more efficiently. Based on these results, the crude capsular extract is a vaccine candidate with immunogenic properties.

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Section: Discussionsupporting

confidence: 79%

The Role of Antibodies Against the Crude Capsular Extract in the Immune Response of Porcine Alveolar Macrophages to In Vitro Infection of Various Serovars of Glaesserella (Haemophilus) parasuis

et al. 2021

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“…We also detected the outer membrane protein 26 that was identified as immunogenic with a protective efficacy against a lethal dose of the G. parasuis serovar 5 in a guinea pig model (Li et al 2016). Furthermore, we also identified the superoxide dismutase (SOD), thioredoxin and glutaredoxin that are other virulence-associated proteins (Guo et al 2016;Li et al 2017;Wen et al 2018). The immunisation of mice with SOD elicited a strong humoral immune response and even provided significant protection against a lethal dose of the G. parasuis serovar 4 or 5 (Guo et al 2016).…”

Section: Discussionmentioning

confidence: 96%

A crude capsular polysaccharide extract as a potential novel subunit vaccine with cross-protection against the most prevalent serovars of Glaesserella (Haemophilus) parasuis in the Czech Republic

Matiašková¹,

Nedbalcová²,

Tesařı́k³

et al. 2019

Vet. Med. - Czech

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Glaesserella (Haemophilus) parasuis is a part of the normal flora of the respiratory tract of pigs. However, under certain conditions it can also induce severe systemic disease with high morbidity and mortality leading to gross economic losses in the pig industry. The most prevalent serovars in pig herds in the Czech Republic are the virulent serovars 1, 4, 5 and 13. The currently available commercial vaccines are inactivated vaccines with certain limitations, such as no or poor cross-serovar protection. Therefore, the aim of the present study was to construct a subunit vaccine with a crude capsular polysaccharide extract (cCPS) isolated from G. parasuis CAPM 6475 (serovar 5) and evaluate its immunogenicity in a mouse model. Mice were immunised subcutaneously with two doses of the constructed vaccine in a 14-day interval and challenged intraperitoneally with various G. parasuis strains (serovars 1, 4, 5, 13) at 21 days after the second immunisation. The results of the ELISA test showed that the boost dose of the vaccine induced the production of IgG antibodies in high levels. On the basis of the death cases, the pathological findings and the bacterial isolation, the mice immunised with the cCPS were partially protected against the challenge with the homologous serovar 5 as well as with heterologous serovars 1, 4 and 13 of G. parasuis. The cross-reaction of the mixed serum from the immunised mice with the tested serovars was seen in the western-blotting also. Moreover, the most abundant protein found in the cCPS by mass spectrometry was catalase, a protein of molecular weight 55 kDa that may correspond to the strongest reaction seen in the western-blotting. Our findings indicated that the crude capsular polysaccharide extract may provide an effective immunogenicity in preventing a G. parasuis infection caused by the most prevalent serovars in the Czech Republic. However, the evaluation of the efficacy needs to be performed in pigs before any conclusions can be drawn.

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“…In addition to stage-specific regulatory functions, certain members of LysR family have roles in biofilm formation through a combination of direct and indirect regulation. For example, OxyR from H. parasuis regulates the DNA-binding transcriptional regulator FabR, which is directly involved in biofilm formation, as well as some membrane-related genes that are indirectly related to biofilm formation, such as an outer membrane assembly protein and an outer-membrane lipoprotein carrier protein [ 20 ]. In the present study, no proteins that are directly related to biofilm formation were identified among the differentially expressed proteins between the ΔlahS and wild-type strains, but RNA polymerase sigma 70 (σ 70 ), which has been reported to participate in the biofilm formation process [ 30 ], was observed to be downregulated.…”

Section: Discussionmentioning

confidence: 99%

“…The LysR family transcription factor LeuO in Vibrio cholerae regulates the transcription of the CarRS two-component regulatory system to control almEFG expression, which contributes to cationic antimicrobial peptide (CAMP) resistance by glycosylation of lipid A [ 19 ]. In Haemophilus parasuis , approximately 500 differentially expressed genes were identified, resulting from the deletion of oxyR , and these genes were involved in various biological processes [ 20 ]. Despite the importance of LTTRs, very little information is currently available regarding their regulation of virulence factors in A. hydrophila .…”

Section: Introductionmentioning

confidence: 99%

Discovery of lahS as a Global Regulator of Environmental Adaptation and Virulence in Aeromonas hydrophila

Dong

Wang

Jin

et al. 2018

IJMS

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Aeromonas hydrophila is an important aquatic microorganism that can cause fish hemorrhagic septicemia. In this study, we identified a novel LysR family transcriptional regulator (LahS) in the A. hydrophila Chinese epidemic strain NJ-35 from a library of 947 mutant strains. The deletion of lahS caused bacteria to exhibit significantly decreased hemolytic activity, motility, biofilm formation, protease production, and anti-bacterial competition ability when compared to the wild-type strain. In addition, the determination of the fifty percent lethal dose (LD50) in zebrafish demonstrated that the lahS deletion mutant (ΔlahS) was highly attenuated in virulence, with an approximately 200-fold increase in LD50 observed as compared with that of the wild-type strain. However, the ΔlahS strain exhibited significantly increased antioxidant activity (six-fold). Label-free quantitative proteome analysis resulted in the identification of 34 differentially expressed proteins in the ΔlahS strain. The differentially expressed proteins were involved in flagellum assembly, metabolism, redox reactions, and cell density induction. The data indicated that LahS might act as a global regulator to directly or indirectly regulate various biological processes in A. hydrophila NJ-35, contributing to a greater understanding the pathogenic mechanisms of A. hydrophila.

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OxyR of Haemophilus parasuis is a global transcriptional regulator important in oxidative stress resistance and growth

Cited by 13 publications

References 55 publications

The Role of Antibodies Against the Crude Capsular Extract in the Immune Response of Porcine Alveolar Macrophages to In Vitro Infection of Various Serovars of Glaesserella (Haemophilus) parasuis

The Role of Antibodies Against the Crude Capsular Extract in the Immune Response of Porcine Alveolar Macrophages to In Vitro Infection of Various Serovars of Glaesserella (Haemophilus) parasuis

A crude capsular polysaccharide extract as a potential novel subunit vaccine with cross-protection against the most prevalent serovars of Glaesserella (Haemophilus) parasuis in the Czech Republic

Discovery of lahS as a Global Regulator of Environmental Adaptation and Virulence in Aeromonas hydrophila

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