Molecular and Functional Characterization of the Porcine Interferon-Omega Subtype
Innate immune interferons (IFNs), particularly type I IFNs, are primary mediators regulating antiviral immunity in vertebrates. These antiviral cytokines have evolved remarkable molecular and functional diversity to confront ever-evolving viral threats in high vertebrates. We have annotated IFN gene families across 155 animal genomes, and shown that pigs have the largest (and still expanding) type I IFN family consisting of nearly 60 functional genes that encode seven IFN subtypes including multigene subtypes of IFN-α and -ω. Whereas subtypes such as IFN-α and -β have been widely studied, the unconventional IFN-ω subtype has barely been investigated. We have evolutionarily defined the porcine IFN family, and displayed that the porcine IFN-ω subtype has evolved several novel features including, 1) a signature multi-gene subtype expanding particularly in bats and ungulates, 2) emerging isoforms that have much higher antiviral potency than typical IFN-α, 3) cross-species high antiviral (but little antiproliferative) activity in cells of humans and other mammalian species, and 4) potential action through non-canonical signaling pathways. This study focuses on antiviral potency of porcine IFN-ωs by investigating their evolutionary and functional diversity, signaling specificity, and optimization of novel antivirals against devastating viral diseases. This thesis project consisted of two parts. The first part involved a gene regulation study in which porcine alveolar macrophages (PAMs) were either infected with a porcine Arterivirus (PRRSV) or treated with different peptides to stimulate IFN response. The expression of IFN-ω genes was determined by a TaqMan- or SYBR Green-based RT-PCR assays. The second part of this project extended to a whole transcriptomic analysis (WTA) using an updated next-generation sequencing procedure in primary porcine macrophages. Both protein-coding mRNA and regulatory non-coding RNA species were genome-wide analyzed in the same bench samples to efficiently compare their differential expression and association patterns upon the stimuli of the viral infection and IFN treatments. This data, for the first time in swine macrophage biology, concentrates on antiviral and IFN-mediated immune responses to elucidate significant gene responsive pathways at a whole transcriptomic level. Increased insight of these pathways will lead to a better understanding of porcine antiviral immunity and facilitate effective anti-PRRSV vaccine design.
Jordan R Jennings,
"Molecular and Functional Characterization of the Porcine Interferon-Omega Subtype"
ETD Collection for Tennessee State University.