Rotavirus-induced IFN-β promotes anti-viral signaling and apoptosis that modulate viral replication in intestinal epithelial cells

Innate Immun. 2012 Apr;18(2):294-306. doi: 10.1177/1753425911401930. Epub 2011 Jul 6.

Abstract

Rotavirus (RV), a leading cause of diarrhea, primarily infects intestinal epithelial cells (IEC). Rotavirus-infected IEC produce IFN-β and express hundreds of IFN-dependent genes. We thus hypothesized that type 1 IFN plays a key role in helping IEC limit RV replication and/or protect against cell death. To test this hypothesis, we examined IEC (HT29 cells) infected with RV (MOI 1) ± neutralizing antibodies to IFN-α/β via microscopy and SDS-PAGE immunoblotting. We hypothesized that neutralization of IFN would be clearly detrimental to RV-infected IEC. Rather, we observed that blockade of IFN function rescued IEC from the apoptotic cell death that otherwise would have occurred 24-48 h following exposure to RV. This resistance to cell death correlated with reduced levels of viral replication at early time points (< 8 h) following infection and eventuated in reduced production of virions. The reduction in RV replication that resulted from IFN neutralization correlated with, and could be recapitulated by, blockade of IFN-induced protein kinase R (PKR) activation, suggesting involvement of this kinase. Interestingly, pharmacologic blockade of caspase activity ablated RV-induced apoptosis and dramatically increased viral protein synthesis, suggesting that IFN-induced apoptosis helps to control RV infection. These results suggest non-mutually exclusive possibilities that IFN signaling is usurped by RV to promote early replication and induction of cell death may be a means by which IFN signaling possibly clears RV from the intestine.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 2-Aminopurine / pharmacology
  • Antibodies, Viral / pharmacology
  • Antimetabolites / pharmacology
  • Apoptosis / drug effects*
  • Blotting, Western
  • Caspase Inhibitors
  • Enzyme Activation / drug effects
  • Enzyme-Linked Immunosorbent Assay
  • Epithelial Cells / drug effects
  • Epithelial Cells / immunology*
  • HT29 Cells
  • Humans
  • In Situ Nick-End Labeling
  • Interferon-beta / biosynthesis*
  • Interferon-beta / immunology
  • Interferon-beta / pharmacology*
  • Intestinal Mucosa / cytology
  • Intestinal Mucosa / virology
  • Intestines / virology
  • Oligopeptides / pharmacology
  • Rotavirus / immunology*
  • Signal Transduction / drug effects*
  • Virus Replication / drug effects*

Substances

  • Antibodies, Viral
  • Antimetabolites
  • Caspase Inhibitors
  • Oligopeptides
  • benzyloxycarbonyl-valyl-alanyl-aspartic acid
  • 2-Aminopurine
  • Interferon-beta