Interferon-induced Ifit2/ISG54 protects mice from lethal VSV neuropathogenesis

PLoS Pathog. 2012;8(5):e1002712. doi: 10.1371/journal.ppat.1002712. Epub 2012 May 17.

Abstract

Interferon protects mice from vesicular stomatitis virus (VSV) infection and pathogenesis; however, it is not known which of the numerous interferon-stimulated genes (ISG) mediate the antiviral effect. A prominent family of ISGs is the interferon-induced with tetratricopeptide repeats (Ifit) genes comprising three members in mice, Ifit1/ISG56, Ifit2/ISG54 and Ifit3/ISG49. Intranasal infection with a low dose of VSV is not lethal to wild-type mice and all three Ifit genes are induced in the central nervous system of the infected mice. We tested their potential contributions to the observed protection of wild-type mice from VSV pathogenesis, by taking advantage of the newly generated knockout mice lacking either Ifit2 or Ifit1. We observed that in Ifit2 knockout (Ifit2(-/-)) mice, intranasal VSV infection was uniformly lethal and death was preceded by neurological signs, such as ataxia and hind limb paralysis. In contrast, wild-type and Ifit1(-/-) mice were highly protected and survived without developing such disease. However, when VSV was injected intracranially, virus replication and survival were not significantly different between wild-type and Ifit2(-/-) mice. When administered intranasally, VSV entered the central nervous system through the olfactory bulbs, where it replicated equivalently in wild-type and Ifit2(-/-) mice and induced interferon-β. However, as the infection spread to other regions of the brain, VSV titers rose several hundred folds higher in Ifit2(-/-) mice as compared to wild-type mice. This was not caused by a broadened cell tropism in the brains of Ifit2(-/-) mice, where VSV still replicated selectively in neurons. Surprisingly, this advantage for VSV replication in the brains of Ifit2(-/-) mice was not observed in other organs, such as lung and liver. Pathogenesis by another neurotropic RNA virus, encephalomyocarditis virus, was not enhanced in the brains of Ifit2(-/-) mice. Our study provides a clear demonstration of tissue-, virus- and ISG-specific antiviral action of interferon.

Publication types

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

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • Apoptosis Regulatory Proteins
  • Brain / virology*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Encephalomyocarditis virus / immunology
  • Encephalomyocarditis virus / pathogenicity
  • Female
  • Interferon-beta / metabolism
  • Liver / virology
  • Lung / virology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Proteins / genetics
  • Proteins / metabolism*
  • RNA-Binding Proteins
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Vesicular Stomatitis / immunology*
  • Vesicular Stomatitis / pathology
  • Vesicular Stomatitis / virology
  • Vesicular stomatitis Indiana virus / immunology
  • Vesicular stomatitis Indiana virus / pathogenicity*
  • Virus Replication

Substances

  • Adaptor Proteins, Signal Transducing
  • Apoptosis Regulatory Proteins
  • Carrier Proteins
  • ISG54 protein, mouse
  • ISG56 protein, mouse
  • Ifit1 protein, mouse
  • Ifit2 protein, mouse
  • Proteins
  • RNA-Binding Proteins
  • Transcription Factors
  • Interferon-beta

Associated data

  • GEO/GSE33678