title: Involvement of two microRNAs in the early immune response to DNA vaccination against a fish rhabdovirus.
abstract: Mechanisms that account for the high protective efficacy in teleost fish of a DNA vaccine expressing the glycoprotein (G) of Viral hemorrhagic septicemia virus (VHSV) are thought to involve early innate immune responses mediated by interferons (IFNs). Microribonucleic acids (miRNAs) are a diverse class of small (18-22 nucleotides) endogenous RNAs that potently mediate post-transcriptional silencing of a wide range of genes and are emerging as critical regulators of cellular processes, including immune responses. We have recently reported that miR-462 and miR-731 were strongly induced in rainbow trout infected with VHSV. In this study, we analyzed the expression of these miRNAs in fish following administration of the DNA vaccine and their potential functions. Quantitative RT-PCR analysis revealed the increased levels of miR-462, and miR-731 in the skeletal muscle tissue at the site of vaccine administration and in the liver of vaccinated fish relative to empty plasmid backbone-injected controls. The increased expression of these miRNAs in the skeletal muscle correlated with the increased levels of the type I interferon (IFN)-inducible gene Mx, type I IFN and IFN-γ genes at the vaccination site. Intramuscular injection of fish with either type I IFN or IFN-γ plasmid construct resulted in the upregulation of miR-462 and miR-731 at the site of injection, suggesting that the induction of these miRNAs is elicited by IFNs. To analyze the function of miR-462 and miR-731, specific silencing of these miRNAs using anti-miRNA oligonucleotides was conducted in poly I:C-treated rainbow trout fingerlings. Following VHSV challenge, anti-miRNA-injected fish had faster development of disease and higher mortalities than control fish, indicating that miR-462/731 may be involved in IFN-mediated protection conferred by poly I:C.
authors.affiliation: Fish Health Section, Department of Animal Science, University of Aarhus, Hangøvej 2, DK-8200 Århus N, Denmark; Section for Immunology and Vaccinology, National Veterinary Institute, Technical University of Denmark, Bulowsvej 27, DK-1870 Frederiksberg C, Denmark. Electronic address: dbelaong@yahoo.com.
authors.forename: Dennis Berbulla
authors.initials: DB
authors.lastname: Bela-ong
authors.affiliation: Section for Immunology and Vaccinology, National Veterinary Institute, Technical University of Denmark, Bulowsvej 27, DK-1870 Frederiksberg C, Denmark.
authors.forename: Brian Dall
authors.initials: BD
authors.lastname: Schyth
authors.affiliation: Scottish Fish Immunology Research Centre, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen AB24 2TZ, Scotland, United Kingdom.
authors.forename: Jun
authors.initials: J
authors.lastname: Zou
authors.affiliation: Scottish Fish Immunology Research Centre, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen AB24 2TZ, Scotland, United Kingdom.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Secombes
authors.affiliation: Fish Health Section, Department of Animal Science, University of Aarhus, Hangøvej 2, DK-8200 Århus N, Denmark. Electronic address: niels.lorenzen@anis.au.dk.
authors.forename: Niels
authors.initials: N
authors.lastname: Lorenzen
mesh_terms: D000818:Animals; D015870:Gene Expression; D006023:Glycoproteins / Q000008:administration & dosage / Q000737:chemistry; D031941:Hemorrhagic Septicemia, Viral / Q000276:immunology / Q000517:prevention & control*; D007113:Immunity, Innate; D007273:Injections, Intramuscular; D007370:Interferon Type I / Q000235:genetics / Q000276:immunology; D007371:Interferon-gamma / Q000276:immunology; D035683:MicroRNAs / Q000235:genetics* / Q000276:immunology; D029141:Novirhabdovirus / Q000276:immunology*; D017686:Oncorhynchus mykiss / Q000276:immunology*; D010957:Plasmids; D011070:Poly I-C / Q000008:administration & dosage; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology*; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D006023:Glycoproteins; D007370:Interferon Type I; D035683:MicroRNAs; D019444:Vaccines, DNA; D014765:Viral Vaccines; D007371:Interferon-gamma; D011070:Poly I-C
keywords: DNA vaccination; Interferons; Rainbow trout; Rhabdovirus glycoprotein; Viral hemorrhagic septicemia virus (VHSV); microRNA