title: Morpholino oligomer-mediated protection of porcine pulmonary alveolar macrophages from arterivirus-induced cell death.
abstract: BACKGROUND
  Porcine reproductive and respiratory syndrome (PRRS) causes extensive economic losses in the swine industry. Current strategies and vaccines to control the disease are inadequate. We previously demonstrated that peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) could potently inhibit PRRS virus (PRRSV) replication in cell cultures. PPMOs are single-stranded DNA analogues containing a modified backbone and cell-penetrating peptide. PPMOs are nuclease-resistant, water-soluble, can enter cells readily and exhibit highly specific binding to complementary RNA. In this study, we examined PPMO-mediated inhibition of PRRSV replication in a primary culture of porcine pulmonary alveolar macrophages (PAMs).
  
  
  METHODS
  PAMs were collected from piglets, pre-incubated in culture and infected with PRRSV. Viability, cytopathic effects, virus yield and apoptosis of PAMs in the presence or absence of a PPMO (5UP2) were examined. The 5UP2 PPMO is complementary to a conserved sequence in the 5'-terminal region of the PRRSV genome. The level of several interferon-associated gene products and activity of caspases were monitored.
  
  
  RESULTS
  PRRSV infection induced the activity of caspases-3/7, -8 and -9 significantly. Treatment of PAMs with 5UP2 resulted in protection of the cells from PRRSV-induced cell death for at least 7 days and avoided the activation of the caspases evaluated. 5UP2 treatment of PRRSV-infected PAMs also prevented the vigorous induction of interferon-beta and chemokines observed in infected and mock-treated PAMs.
  
  
  CONCLUSIONS
  PPMO-mediated suppression of PRRSV replication in PAMs was associated with a reduction of apoptotic and inflammatory responses. These results provide further rationale for the development of PPMO 5UP2 as an antiviral to control PRRSV infection.
authors.affiliation: University of Maryland, College Park, MD, USA.
authors.forename: Deendayal
authors.initials: D
authors.lastname: Patel
authors.forename: David A
authors.initials: DA
authors.lastname: Stein
authors.forename: Yan-Jin
authors.initials: YJ
authors.lastname: Zhang
mesh_terms: D000818:Animals; D020169:Caspases / Q000096:biosynthesis; D018929:Cell Culture Techniques; D016923:Cell Death / Q000187:drug effects; D018925:Chemokines / Q000096:biosynthesis / Q000235:genetics; D004790:Enzyme Induction / Q000187:drug effects; D015967:Gene Expression Regulation, Viral / Q000187:drug effects; D054884:Host-Pathogen Interactions / Q000187:drug effects; D016899:Interferon-beta / Q000096:biosynthesis / Q000235:genetics; D016676:Macrophages, Alveolar / Q000187:drug effects* / Q000502:physiology / Q000821:virology; D009025:Morpholines / Q000494:pharmacology*; D060172:Morpholinos; D019318:Porcine Reproductive and Respiratory Syndrome / Q000188:drug therapy* / Q000378:metabolism; D019316:Porcine respiratory and reproductive syndrome virus / Q000187:drug effects* / Q000502:physiology; D013552:Swine; D014779:Virus Replication / Q000187:drug effects
chemical_list: D018925:Chemokines; D009025:Morpholines; D060172:Morpholinos; D016899:Interferon-beta; D020169:Caspases