High-throughput proteomic profiling of the fish liver following bacterial infection

Abstract Background High-throughput proteomics was used to determine the role of the fish liver in defense responses to bacterial infection. This was done using a rainbow trout (Oncorhynchus mykiss) model following infection with Aeromonas salmonicida, the causative agent of furunculosis. The vertebrate liver has multifaceted functions in innate immunity, metabolism, and growth; we hypothesize this tissue serves a dual role in supporting host defense in parallel to metabolic adjustments that promote effective immune function. While past studies have reported mRNA responses to A. salmonicida in salmonids, the impact of bacterial infection on the liver proteome remains uncharacterized in fish. Results Rainbow trout were injected with A. salmonicida or PBS (control) and liver extracted 48 h later for analysis on a hybrid quadrupole-Orbitrap mass spectrometer. A label-free method was used for protein abundance profiling, which revealed a strong innate immune response along with evidence to support parallel rewiring of metabolic and growth systems. 3076 proteins were initially identified against all proteins (n = 71,293 RefSeq proteins) annotated in a single high-quality rainbow trout reference genome, of which 2433 were maintained for analysis post-quality filtering. Among the 2433 proteins, 109 showed significant differential abundance following A. salmonicida challenge, including many upregulated complement system and acute phase response proteins, in addition to molecules with putative functions that may support metabolic re-adjustments. We also identified novel expansions in the complement system due to gene and whole genome duplication events in salmonid evolutionary history, including eight C3 proteins showing differential changes in abundance. Conclusions This study provides the first high-throughput proteomic examination of the fish liver in response to bacterial challenge, revealing novel markers for the host defense response, and evidence of metabolic remodeling in conjunction with activation of innate immunity

The AMPK system of salmonid fishes was expanded through genome duplication and is regulated by growth and immune status in muscle

Acknowledgements DRC’s PhD studentship is supported through Te Developmental Trust and Elphinstone Scholarship Programme of the University of Aberdeen. DJM acknowledges support from BBSRC Institute Strategic Programme funding to The Roslin Institute (grant ref: BBS/E/D/10002071).Peer reviewedPublisher PD

Plasma proteome responses in salmonid fish following immunization

Data Availability Statement The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found in the article/Supplementary Material. Ethics Statement The animal study was reviewed and approved by UK home office and University of Aberdeen’s Animal Welfare and Ethical Review Body (AWERB). Author Contributions Study conception and design: DM and HD. Animal work: MM and HD. Proteomics lab work: DS. Proteomic data analysis: FB, DC, AD. Data interpretation: FB, DM, and HD. Drafted figures and tables: FB and DM. Drafted manuscript: FB, DM, and HD. All authors contributed to the article and approved the submitted version. Funding This work was supported by the Biotechnology and Biological Sciences Research Council (BBSRC) grant numbers: BB/M010996/1, BB/M026345/1, BBS/E/D/20002174, and BBS/E/D/10002071. Conflict of Interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Acknowledgments Our thanks to Prof. Chris Secombes (University of Aberdeen) for the 4C10 anti-salmonid IgM mAb used in our ELISAs and for his valuable intellectual contributions during the planning of this project. We also gratefully acknowledge the supervisory support given by Prof. Sam Martin (University of Aberdeen) to FB.Peer reviewedPublisher PD

Proteomic comparison of selective breeding and growth hormone transgenesis in fish:Unique pathways to enhanced growth

Open Access funded by Biotechnology and Biological Sciences Research CouncilPeer reviewedPublisher PD