title: RNA-sequence analysis of primary alveolar macrophages after in vitro infection with porcine reproductive and respiratory syndrome virus strains of differing virulence.
abstract: Porcine reproductive and respiratory syndrome virus (PRRSV) mainly infects porcine alveolar macrophages (PAMs), resulting in porcine reproductive and respiratory syndrome (PRRS) in pigs. Most of the transcriptomic studies on PAMs infected with PRRSV conducted thus far have made use of microarray technology. Here, we investigated the transcriptome of PAMs in vitro at 12 h post-infection with two European PRRSV strains characterized by low (Lelystad, LV) and high (Lena) virulence through RNA-Seq. The expression levels of genes, isoforms, alternative transcription start sites (TSS) and differential promoter usage revealed a complex pattern of transcriptional and post-transcriptional gene regulation upon infection with the two strains. Gene ontology analysis confirmed that infection of PAMs with both the Lena and LV strains affected signaling pathways directly linked to the innate immune response, including interferon regulatory factors (IRF), RIG1-like receptors, TLRs and PKR pathways. The results confirmed that interferon signaling is crucial for transcriptional regulation during PAM infection. IFN-β1 and IFN-αω, but not IFN-α, were up-regulated following infection with either the LV or Lena strain. The down-regulation of canonical pathways, such as the interplay between the innate and adaptive immune responses, cell death and TLR3/TLR7 signaling, was observed for both strains, but Lena triggered a stronger down-regulation than LV. This analysis contributes to a better understanding of the interactions between PRRSV and PAMs and outlines the differences in the responses of PAMs to strains with different levels of virulence, which may lead to the development of new PRRSV control strategies.
authors.affiliation: Parco Tecnologico Padano, Via Einstein, Lodi, Italy.
authors.forename: Bouabid
authors.initials: B
authors.lastname: Badaoui
authors.affiliation: Parco Tecnologico Padano, Via Einstein, Lodi, Italy.
authors.forename: Teresa
authors.initials: T
authors.lastname: Rutigliano
authors.affiliation: Parco Tecnologico Padano, Via Einstein, Lodi, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Anselmo
authors.affiliation: Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium.
authors.forename: Merijn
authors.initials: M
authors.lastname: Vanhee
authors.affiliation: Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium.
authors.forename: Hans
authors.initials: H
authors.lastname: Nauwynck
authors.affiliation: Parco Tecnologico Padano, Via Einstein, Lodi, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Giuffra
authors.affiliation: Parco Tecnologico Padano, Via Einstein, Lodi, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Botti
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation / Q000276:immunology*; D054884:Host-Pathogen Interactions; D007113:Immunity, Innate / Q000235:genetics*; D050835:Interferon Regulatory Factors / Q000235:genetics / Q000276:immunology; D008168:Lung / Q000276:immunology / Q000473:pathology / Q000821:virology; D016676:Macrophages, Alveolar / Q000276:immunology* / Q000473:pathology / Q000821:virology; D058977:Molecular Sequence Annotation; D019316:Porcine respiratory and reproductive syndrome virus / Q000145:classification / Q000472:pathogenicity* / Q000502:physiology; D061251:Primary Cell Culture; D018168:Receptors, Retinoic Acid / Q000235:genetics / Q000276:immunology; D017423:Sequence Analysis, RNA; D015398:Signal Transduction; D013045:Species Specificity; D013552:Swine; D051193:Toll-Like Receptors / Q000235:genetics / Q000276:immunology; D059467:Transcriptome / Q000276:immunology*; D014774:Virulence
chemical_list: D050835:Interferon Regulatory Factors; D018168:Receptors, Retinoic Acid; D051193:Toll-Like Receptors