Single cell transcriptomics of Atlantic salmon (Salmo salar L.) liver reveals cellular heterogeneity and immunological responses to challenge by Aeromonas salmonicida
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ABSTRACT:
ORGANISM(S): Salmo salar
PROVIDER: GSE207655 | GEO | 2022/08/16
REPOSITORIES: GEO
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Project description:Background Aeromonas salmonicida subsp. salmonicida, the etiologic agent of furunculosis, is a major pathogen of fisheries worldwide. Despite the identification of several virulence factors the pathogenesis is still poorly understood. We have used high-throughput proteomics to display the differences between in vitro secretome of A. salmonicida wild-type (wt, hypervirulent, JF5054) and T3SS-deficient (isogenic DeltaascV, extremely low-virulent, JF2747) strains in exponential (GP) and stationary (SP) phases of growth. Results Among the different experimental conditions we obtained semi-quantitative values for a total of 2136 A. salmonicida proteins. Proteins of specific A. salmonicida species were proportionally less detected than proteins common to the Aeromonas genus or those shared with other Aeromonas species, suggesting that in vitro growth did not induce the expression of these genes. Four detected proteins which are unidentified in the genome of reference strains of A. salmonicida were homologous to components of the conjugative T4SS of A. hydrophila pRA1 plasmid. Polypeptides of three proteins which are specific to the 01-B526 strain were also discovered. In supernatants (SNs), the number of detected proteins was higher in SP (326 for wt vs 329 for mutant) than in GP (275 for wt vs 263 for mutant). In pellets, the number of identified proteins (a total of 1536) was approximately the same between GP and SP. Numerous highly conserved cytoplasmic proteins were present in A. salmonicida SNs (mainly EF-Tu, EF-G, EF-P, EF-Ts, TypA, AlaS, ribosomal proteins, HtpG, DnaK, peptidyl-prolyl cis-trans isomerases, GAPDH, Enolase, FbaA, TpiA, Pgk, TktA, AckA, AcnB, Mdh, AhpC, Tpx, SodB and PNPase), and several evidences support the theory that their extracellular localization was not the result of cell lysis. According to the Cluster of Orthologous Groups classification, 29% of excreted proteins in A. salmonicida SNs were currently poorly characterized. Conclusions In this part of our work we elucidated the whole in vitro exoproteome of hypervirulent A. salmonicida subsp. salmonicida and showed the secretion of several highly conserved cytoplasmic proteins with putative moonlighting functions and roles in virulence. All together, our results offer new information about the pathogenesis of furunculosis and point out potential candidates for vaccine development.
2013-11-11 | PXD000429 | Pride
Project description:Aeromonas salmonicida is a fish pathogen that causes furunculosis. Virulent strains of this bacterium are able to infect salmonid macrophages and survive within them, although mechanisms favouring intracellular survival are not completely understood. It is known that A. salmonicida cultured in vivo in the peritoneal cavity of the host undergoes changes in gene expression and surface architecture compared with cultures grown in vitro in broth. Therefore, in this study, the macrophage responses to A. salmonicida grown in vivo and in vitro were compared. Enriched macrophages isolated from head kidney of Atlantic salmon (Salmo salar) were infected in vitro in 96-well microtitre dishes and changes in gene expression during the infection process were monitored using a custom Atlantic salmon cDNA microarray. A. salmonicida cultures grown in tryptic soy broth and in peritoneal implants were used to infect the macrophages. The macrophages were harvested at 0.5, 1.0 and 2.0 h after addition of the bacteria to the medium. Significant changes in gene expression were evident by microarray analysis at 2.0 h post-infection in macrophages infected with broth-grown and implant-grown bacteria; however, qPCR analysis revealed earlier up-regulation of JunB and TNF-alpha in macrophages exposed to the implant-grown bacteria. Up-regulation of those genes and others is consistent with the effects of extracellular products of aeromonad bacteria on macrophages and also suggests initiation of the innate immune response. Keywords: time course
2008-02-27 | GSE8526 | GEO
Project description:Aeromonas salmonicida is a fish pathogen that causes furunculosis. Virulent strains of this bacterium are able to infect salmonid macrophages and survive within them, although mechanisms favouring intracellular survival are not completely understood. It is known that A. salmonicida cultured in vivo in the peritoneal cavity of the host undergoes changes in gene expression and surface architecture compared with cultures grown in vitro in broth. Therefore, in this study, the macrophage responses to A. salmonicida grown in vivo and in vitro were compared. Enriched macrophages isolated from head kidney of Atlantic salmon (Salmo salar) were infected in vitro in 96-well microtitre dishes and changes in gene expression during the infection process were monitored using a custom Atlantic salmon cDNA microarray. A. salmonicida cultures grown in tryptic soy broth and in peritoneal implants were used to infect the macrophages. The macrophages were harvested at 0.5, 1.0 and 2.0 h after addition of the bacteria to the medium. Significant changes in gene expression were evident by microarray analysis at 2.0 h post-infection in macrophages infected with broth-grown and implant-grown bacteria; however, qPCR analysis revealed earlier up-regulation of JunB and TNF-alpha in macrophages exposed to the implant-grown bacteria. Up-regulation of those genes and others is consistent with the effects of extracellular products of aeromonad bacteria on macrophages and also suggests initiation of the innate immune response. Keywords: time course Enriched macrophages from 24 responder fish that showed positive respiratory burst in response to phorbol myristate acetate were plated in individual wells of 96-well flat-bottom polystyrene tissue culture plates. A. salmonicida were added to the macrophages, and incubated for 0.5, 1.0 or 2.0 h. Control wells received 10 ul of HBSS. Three replicate infections were performed for each type of bacteria. Hybridizations were carried out in duplicate, reversing the fluors for each sample on the second chip.
2010-05-26 | E-GEOD-8526 | biostudies-arrayexpress
Project description:Aeromonas salmonicida Genome sequencing
| PRJNA314146 | ENA
Project description:Aeromonas caviae has been associated with human gastrointestinal disease. Strains of this species typically lack virulence factors (VFs) such as enterotoxins and hemolysins that are produced by other human pathogens of the Aeromonas genus. Microarray profiling of murine small intestinal extracts, 24 hours after oral infection with an A. caviae strain, provides evidence of a Th1 type immune response. A large number of gamma-interferon (γ-IFN) induced genes are up-regulated as well as several tumor necrosis factor-alpha (TNF-α) transcripts. A. caviae has always been considered an opportunistic pathogen because it lacks obvious virulence factors. This current effort suggests A. caviae colonizes murine intestinal tract and causes what has been described by others as a dysregulatory cytokine response leading to an irritable bowel-like syndrome. This response would explain why a number of diarrheal waterborne outbreaks have been attributed to A. caviae even though it lacks obvious enteropathogenic properties. Keywords: Aeromonas caviae, infection, disease mechanism, TH1 resposne
2007-01-20 | GSE6765 | GEO
Project description:To study the effects of bacterial infection upon gene expression changes in flounder liver fish were artificially "infected" by injection with a commercial water-based vaccine containing killed Aeromonas salmonicida, the bacterium responsible for furunculosis, which, as its name describes, presents as external lesions (furuncles, "lumps"). This disease occurs in flounder as well as in salmonids. Flounders were treated by intraperitoneal injection with 1ml/kg Furunculosis vaccine (Schering-Plough, Aquavac Furovac 5, batch number FNM/C/007). 30 control fish were injected with 1% saline. Animals were then maintained unfed in static aerated sea water tanks in a constant temperature containment aquarium. Water was renewed every 2 days. After 1, 2, 4, 8, and 16 days, 6 vaccine treated and 6 saline control fish were removed, killed by a blow to the head and samples of liver tissue were immediately homogenized in TriReagent prior to gene expression profiling. Microarray experiments consisted an individual array for each of 4 or 5 fish from each timepoint and each treatment compared with an artificial reference sample.
2009-06-16 | E-MAXD-38 | biostudies-arrayexpress
Project description:Aeromonas salmonicida Genome sequencing and assembly
| PRJNA264317 | ENA
Project description:The agent of furunculosis, a major cause of mortality among salmonid fishes
| PRJNA16665 | ENA
Project description:Aims: To assess the virulence of multiple Aeromonas spp. using two models, a neonatal mouse assay and a mouse intestinal cell culture. Methods and Results: Transcriptional responses to both infection models were evaluated using microarrays. After artificial infection with a variety of Aeromonas spp., mRNA extracts from the two models were processed and hydridized to murine microarrays to determine host gene response. Definition of virulence was determined based on host mRNA production in murine neonatal intestinal tissue and mortality of infected animals. Infections of mouse intestinal cell cultures were then performed to determine whether this simpler model system's mRNA responses correlated to neonatal results and therefore be predictive of virulence of Aeromonas spp. Virulent aeromonads up-regulated transcripts in both models including multiple host defense gene products (chemokines, regulation of transcription and apoptosis, cell signaling). Avirulent species exhibited little or no host response in neonates. Mortality results correlated well with both bacterial dose and average fold change of up-regulated transcripts in the neonatal mice. Conclusions: Cell culture results were less discriminating but showed promise as potentially being able to be predictive of virulence. Jun oncogene up-regulation in murine cell culture is potentially predictive of Aeromonas virulence. Significance and Impact of the Study: Having the ability to determine virulence of waterborne pathogens quickly would potentially assist public health officials to rapidly assess exposure risks. Keywords: Aeromonas; Virulence; Gene expression; Host response
2006-10-21 | GSE6065 | GEO
Project description:Aeromonas salmonicida subsp. salmonicida Genome sequencing and assembly
| PRJNA376116 | ENA