Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Biology
Program Name/Specialization
Biological and Chemical Sciences
Faculty/School
Faculty of Science
First Advisor
Stephanie DeWitte-Orr
Advisor Role
Principal Investigator
Abstract
The aquaculture industry is a big part of the global economy, supplying food and supporting many livelihoods, yet it faces formidable challenges from diverse aquatic pathogens, especially viruses. Effective antiviral treatments are lacking for both humans and economically significant farmed fish like rainbow trout (Oncorhynchus mykiss). When viruses invade host cells, pattern recognition receptors detect viral components, initiating intracellular signaling and type I interferon (IFN-I) production. IFN-I triggers interferon-stimulated genes (ISGs) that establish an antiviral state in infected and nearby cells, curbing viral spread. In rainbow trout, a particularly understudied ISG is viral hemorrhagic septicemia virus (VHSV)-induced gene 3 (vig-3), analogous to ISG15 in humans and other fish species. This thesis investigates vig-3 and ISG15 from two perspectives: in rainbow trout and in humans, alongside novel immune stimulants. Firstly, vig-3’s expression patterns and cellular localization in response to a dsRNA molecule, polyinosinic: polycytidylic acid acid (poly IC), and infection with infectious pancreatic necrosis virus (IPNV) and VHSV in rainbow trout were elucidated. Vig-3 exhibited ISGylation and significant induction upon stimulation with IFN-I, poly IC, and viral infection at the mRNA transcript and protein levels. Secondly, a novel phytoglycogen-based nanoparticle (Nanodendrix; NDx) was assessed as a potential immune activator of IFN-I, vig-3, and inflammatory agents, and as an antiviral prophylactic in rainbow trout cell lines. NDx combined with poly IC induced substantial IFN-I and vig-3 levels and provided protection against IPNV. Thirdly, ISG15’s expression patterns were examined when treated with poly IC and its efficacy as an antiviral treatment in human lung cells infected with human coronavirus 229E (HCoV-229E), or vesicular stomatitis virus (VSV) was explored. ISG15 was produced intracellularly and extracellularly when treated with poly IC, and recombinant ISG15 protected against VSV infection. Lastly, NDx formulations were evaluated for their ability to induce immune genes, including ISG15 at the transcript level, and as potential antivirals in human lung cells. NDx formulations induced significant ISG15 levels and mitigated coronavirus replication. This research enhances our understanding of innate immune responses in rainbow trout and humans, potentially informing the development of antiviral therapies for both species in the future.
Recommended Citation
Jenik, Kristof; Poynter, Sarah J.; Herrington-Krause, Shanee; Samms, Kayla; Diaz, Nichole Sanchez; DeWitte-Orr, Stephanie J.; Rodriguez-Ramos, Tania; Dixon, Brian; Sanyaolu, Adebisi; Alkie, Tamiru; Warner, Bryce M.; Tailor, Nikesh; and Semple, Shawna, "A comparative in vitro investigation of rainbow trout vig-3 and human ISG15" (2024). Theses and Dissertations (Comprehensive). 2698.
https://scholars.wlu.ca/etd/2698
Convocation Year
2024
Convocation Season
Fall
Included in
Diseases Commons, Integrative Biology Commons, Medical Immunology Commons, Nanotechnology Commons
Comments
The aquaculture industry is a big part of the global economy, supplying food and supporting many livelihoods, yet it faces formidable challenges from diverse aquatic pathogens, especially viruses. Effective antiviral treatments are lacking for both humans and economically significant farmed fish like rainbow trout (Oncorhynchus mykiss). When viruses invade host cells, pattern recognition receptors detect viral components, initiating intracellular signalling and type I interferon (IFN-I) production. IFN-I triggers interferon-stimulated genes (ISGs) that establish an antiviral state in infected and nearby cells, curbing viral spread. In rainbow trout, a particularly understudied ISG is viral hemorrhagic septicemia virus (VHSV)-induced gene 3 (vig-3), analogous to ISG15 in humans and other fish species. This thesis investigates vig-3 and ISG15 from two perspectives: in rainbow trout and in humans, alongside novel immune stimulants. Firstly, vig-3’s expression patterns and cellular localization in response to a dsRNA molecule, polyinosinic: polycytidylic acid acid (poly IC), and infection with infectious pancreatic necrosis virus (IPNV) and VHSV in rainbow trout were elucidated. Vig-3 exhibited ISGylation and significant induction upon stimulation with IFN-I, poly IC, and viral infection at the mRNA transcript and protein levels. Secondly, a novel phytoglycogen-based nanoparticle (Nanodendrix; NDx) was assessed as a potential immune activator of IFN-I, vig-3, and inflammatory agents, and as an antiviral prophylactic in rainbow trout cell lines. NDx combined with poly IC induced substantial IFN-I and vig-3 levels and provided protection against IPNV. Thirdly, ISG15’s expression patterns were examined when treated with poly IC and its efficacy as an antiviral treatment in human lung cells infected with human coronavirus 229E (HCoV-229E), or vesicular stomatitis virus (VSV) was explored. ISG15 was produced intracellularly and extracellularly when treated with poly IC, and recombinant ISG15 protected against VSV infection. Lastly, NDx formulations were evaluated for their ability to induce immune genes, including ISG15 at the transcript level, and as potential antivirals in human lung cells. NDx formulations induced significant ISG15 levels and mitigated coronavirus replication. This research enhances our understanding of innate immune responses in rainbow trout and humans, potentially informing the development of antiviral therapies for both species in the future.