Deciphering the interplay between the ulcerome and wound healing processes in skin ulcers of Atlantic salmon for improved immune prevention

This project aims to tackle the problem of skin ulcers in farmed Atlantic salmon, often caused by bacteria that infect wounds from mechanical delousing. These ulcers, harboring harmful bacteria like Moritella viscosa, Tenacibaculum sp., and Aliivibrio wodanis, are difficult to heal and pose significant challenges to salmon health and aquaculture profitability. We will be investigating how these bacteria interact with the wound-healing process of fish to develop better prevention strategies, including vaccines. By studying how these bacteria invade and persist in wounds and understanding why the salmon immune system struggles to heal, the project hopes to design effective vaccines, including DNA and mRNA options, to boost fish immunity. Using advanced techniques, like RNAscope and RNA sequencing, scientists will profile immune responses directly in fish wounds and through isolated immune cells at various healing stages. The study combines bacterial biology, fish immune systems, and vaccine technology expertise. Success could improve fish health, reduce ulcer rates, and promote sustainable practices in salmon farming.

The project explores the interaction between ulcer-causing bacteria (ulcerome) and the wound-healing process in Atlantic salmon skin ulcers to enhance immune prevention strategies. Skin ulcers, primarily caused by mechanical delousing methods, pose significant welfare and economic challenges in salmon aquaculture. These ulcers are often infected by bacteria like Moritella viscosa, Tenacibaculum sp., and Aliivibrio wodanis, which can form biofilms and thrive with many by-standing bacterial species, complicating the healing process. We ask a simple question - can a better understanding of the pathogenicity profiles of ulcer-forming bacteria be translated for improved prevention of skin ulcers in salmon? The project seeks to understand the colonization and infection mechanisms of these bacteria, the host's failure to regenerate lesions, and to develop effective vaccination strategies based on virulence factors like lytic polysaccharide monooxygenases (LPMOs) and exopolysaccharides (EPS). It will employ a comprehensive approach combining pathogen characterization, immune response analysis, and innovative vaccine design, including recombinant protein vaccines, and DNA and mRNA vaccines. The wound healing process is studied in situ and ex vivo by immune profiling using RNAscope methodology (in situ) and isolation of macrophage populations from skin wounds at different stages of inflammation and regeneration (ex vivo). Immune profiling will include RNAseq studies of isolated macrophage populations. The project's interdisciplinary team will leverage advanced methodologies and extensive expertise in bacterial virulence, fish immunology, and vaccine development. This research could significantly impact salmon farming by reducing ulcer incidence, improving fish welfare, and contributing to the sustainability of aquaculture operations.