<i>Renibacterium salmoninarum</i> iron‐acquisition <i>mechanisms</i> and ASK cell line infection: Virulence and immune response

Bethke, Jörn; Arias‐Muñoz, Eloisa; Yáñez, Alejandro J.; Avendaño‐Herrera, Rubén

doi:10.1111/jfd.13051

Cited by 16 publications

(27 citation statements)

References 29 publications

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“…This strain was isolated from fish with clinical signs of BKD in southern Chile. Previous studies showed that strain H-2 has high siderophore production, which can result in high virulence potential (14,32,33). The strain identification was confirmed as R. salmoninarum with nested PCR, as described by Chase and Pascho (34), and culture purity was confirmed by Gram-staining, cell morphology and colony morphology (33).…”

Section: R Salmoninarum Strain and Culturementioning

confidence: 99%

“…An enhanced understanding of the Atlantic salmon response to R. salmoninarum can aid in the development of preventive management tools for BKD (e.g., vaccines and therapeutic diets). Previous in vivo and in vitro studies examined gene expression responses to R. salmoninarum in rainbow trout (11) and Chinook salmon (O. tshawytscha) (12) kidney as well as rainbow trout macrophages (13) and Atlantic Salmon Kidney (ASK) cell line (14). A genomics-based study used Suppression Subtractive Hybridisation (SSH) to identify BKD-responsive genes in Chinook salmon (15).…”

Section: Introductionmentioning

confidence: 99%

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Transcriptomic Profiling of the Adaptive and Innate Immune Responses of Atlantic Salmon to Renibacterium salmoninarum Infection

et al. 2020

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Bacterial Kidney Disease (BKD), which is caused by a Gram-positive, intracellular bacterial pathogen (Renibacterium salmoninarum), affects salmonids including Atlantic salmon (Salmo salar). However, the transcriptome response of Atlantic salmon to BKD remained unknown before the current study. We used a 44K salmonid microarray platform to characterise the global gene expression response of Atlantic salmon to BKD. Fish (∼54 g) were injected with a dose of R. salmoninarum (H-2 strain, 2 × 10 8 CFU per fish) or sterile medium (control), and then head kidney samples were collected at 13 days post-infection/injection (dpi). Firstly, infection levels of individuals were determined through quantifying the R. salmoninarum level by RNA-based TaqMan qPCR assays. Thereafter, based on the qPCR results for infection level, fish (n = 5) that showed no (control), higher (H-BKD), or lower (L-BKD) infection level at 13 dpi were subjected to microarray analyses. We identified 6,766 and 7,729 differentially expressed probes in the H-BKD and L-BKD groups, respectively. There were 357 probes responsive to the infection level (H-BKD vs. L-BKD). Several adaptive and innate immune processes were dysregulated in R. salmoninarum-infected Atlantic salmon. Adaptive immune pathways associated with lymphocyte differentiation and activation (e.g., lymphocyte chemotaxis, T-cell activation, and immunoglobulin secretion), as well as antigen-presenting cell functions, were shown to be differentially regulated in response to BKD. The infection level-responsive transcripts were related to several mechanisms such as the JAK-STAT signalling pathway, B-cell differentiation and interleukin-1 responses. Sixty-five microarray-identified transcripts were subjected to qPCR validation, and they showed the same fold-change direction as microarray results. The qPCRvalidated transcripts studied herein play putative roles in various immune processes including pathogen recognition (e.g., tlr5), antibacterial activity (e.g., hamp and camp), regulation of immune responses (e.g., tnfrsf11b and socs1), T-/B-cell differentiation (e.g., ccl4, irf1 and ccr5), T-cell functions (e.g., rnf144a, il13ra1b and tnfrsf6b), and Eslamloo et al. Atlantic Salmon Response to BKD antigen-presenting cell functions (e.g., fcgr1). The present study revealed diverse immune mechanisms dysregulated by R. salmoninarum in Atlantic salmon, and enhanced the current understanding of Atlantic salmon response to BKD. The identified biomarker genes can be used for future studies on improving the resistance of Atlantic salmon to BKD.

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Section: R Salmoninarum Strain and Culturementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transcriptomic Profiling of the Adaptive and Innate Immune Responses of Atlantic Salmon to Renibacterium salmoninarum Infection

et al. 2020

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“…Grayson et al [ 100 ] investigated iron acquisition in R. salmoninarum and have reported that non-hydrophobic strains were not able to grow properly under iron-restricted conditions compared with hydrophobic strains. Additionally, two iron acquisition systems (siderophores and haeme) have been described by Bethke et al [ 101 ]. Recently, Bethke et al [ 101 ] investigated the expression of bacterial genes and host immune genes during in vitro infection of a cell line (Atlantic salmon kidney cells) and culture under iron-limited conditions.…”

Section: Virulence Mechanismsmentioning

confidence: 99%

“…Additionally, two iron acquisition systems (siderophores and haeme) have been described by Bethke et al [ 101 ]. Recently, Bethke et al [ 101 ] investigated the expression of bacterial genes and host immune genes during in vitro infection of a cell line (Atlantic salmon kidney cells) and culture under iron-limited conditions. These authors reported that several bacterial genes such as HmuTUV cluster, the siderophore transporters FecB and FecD, the siderophore esterase Est.1 and Est.2 and the ferrous transporter FTR-1 were overexpressed under iron limited conditions, suggesting that these genes play a role in iron acquisition.…”

Section: Virulence Mechanismsmentioning

confidence: 99%

“…These authors reported that several bacterial genes such as HmuTUV cluster, the siderophore transporters FecB and FecD, the siderophore esterase Est.1 and Est.2 and the ferrous transporter FTR-1 were overexpressed under iron limited conditions, suggesting that these genes play a role in iron acquisition. While this study was performed in vitro, these findings might be useful for creating novel treatment via disrupting the iron uptake [ 101 ].…”

Section: Virulence Mechanismsmentioning

confidence: 99%

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Renibacterium salmoninarum—The Causative Agent of Bacterial Kidney Disease in Salmonid Fish

2020

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Renibacterium salmoninarum is one of the oldest known bacterial pathogens of fish. This Gram-positive bacterium is the causative agent of bacterial kidney disease, a chronic infection that is mostly known to infect salmonid fish at low temperatures. Externally, infected fish can display exophthalmia as well as blebs on the skin and ulcerations alongside haemorrhages at the base of the fins and alongside the lateral line. Internally, the kidney, heart, spleen and liver can show signs of swelling. Granulomas can be seen on various internal organs, as can haemorrhages, and the organs can be covered with a false membrane. Ascites can also accumulate in the abdominal cavity. The bacterium is generally cultivated on specialized media such as kidney disease medium-1 (KDM-1), KDM-2 and selective kidney disease medium (SKDM), and a diagnostic is performed using molecular tools such as PCRs or real-time quantitative PCRs (RT-qPCRs). Several virulence mechanisms have been identified in R. salmoninarum, in particular the protein p57 that is known to play a role in both agglutination and immunosuppression of the host’s defense mechanisms. Control of the disease is difficult; the presence of asymptomatic carriers complicates the eradication of the disease, as does the ability of the bacterium to gain entrance inside the eggs. Bacterin-killed vaccines have proven to be of doubtful efficacy in controlling the disease, and even more recent application of a virulent environmental relative of R. salmoninarum is of limited efficacy. Treatment by antibiotics such as erythromycin, azithromycin and enrofloxacin can be effective but it is slow and requires prolonged treatment. Moreover, antibiotic-resistant strains have been reported. Despite being known for a long time, there is still much to be discovered about R. salmoninarum, notably regarding its virulence mechanisms and its vaccine potential. Consequently, these gaps in knowledge continue to hinder control of this bacterial disease in aquaculture settings.

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In vitro salmonid models as tools for studying microbial-derived immunostimulants and aquaculture relevant salmonids pathogens: Current status and future perspectives

Mensah,

Montero,

Morales-Lange

et al. 2025

Aquaculture

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Renibacterium salmoninarum iron‐acquisition mechanisms and ASK cell line infection: Virulence and immune response

Cited by 16 publications

References 29 publications

Transcriptomic Profiling of the Adaptive and Innate Immune Responses of Atlantic Salmon to Renibacterium salmoninarum Infection

Transcriptomic Profiling of the Adaptive and Innate Immune Responses of Atlantic Salmon to Renibacterium salmoninarum Infection

Renibacterium salmoninarum—The Causative Agent of Bacterial Kidney Disease in Salmonid Fish

In vitro salmonid models as tools for studying microbial-derived immunostimulants and aquaculture relevant salmonids pathogens: Current status and future perspectives

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