SIDT2 Transports Extracellular dsRNA into the Cytoplasm for Innate Immune Recognition

Immunity. 2017 Sep 19;47(3):498-509.e6. doi: 10.1016/j.immuni.2017.08.007. Epub 2017 Sep 12.

Abstract

Double-stranded RNA (dsRNA) is a common by-product of viral infections and acts as a potent trigger of antiviral immunity. In the nematode C. elegans, sid-1 encodes a dsRNA transporter that is highly conserved throughout animal evolution, but the physiological role of SID-1 and its orthologs remains unclear. Here, we show that the mammalian SID-1 ortholog, SIDT2, is required to transport internalized extracellular dsRNA from endocytic compartments into the cytoplasm for immune activation. Sidt2-deficient mice exposed to extracellular dsRNA, encephalomyocarditis virus (EMCV), and herpes simplex virus 1 (HSV-1) show impaired production of antiviral cytokines and-in the case of EMCV and HSV-1-reduced survival. Thus, SIDT2 has retained the dsRNA transport activity of its C. elegans ortholog, and this transport is important for antiviral immunity.

Keywords: EMCV; HSV; MAVS; SIDT2; bystander immunity; double-stranded RNA; type I interferon; virus infection.

MeSH terms

  • Animals
  • Cardiovirus Infections / genetics
  • Cardiovirus Infections / immunology
  • Cell Line
  • Cytoplasm
  • DEAD Box Protein 58 / metabolism
  • Disease Models, Animal
  • Encephalomyocarditis virus / genetics
  • Encephalomyocarditis virus / immunology
  • Endosomes / metabolism
  • Female
  • Gene Expression
  • Gene Knockout Techniques
  • Herpes Simplex / genetics
  • Herpes Simplex / immunology
  • Herpesvirus 1, Human / genetics
  • Herpesvirus 1, Human / immunology
  • Host-Pathogen Interactions / genetics
  • Host-Pathogen Interactions / immunology
  • Immunity, Innate*
  • Lysosomes / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Knockout
  • Nucleotide Transport Proteins
  • Protein Binding
  • Protein Transport
  • RNA Transport*
  • RNA, Double-Stranded / immunology*
  • RNA, Double-Stranded / metabolism*
  • RNA, Viral / genetics
  • RNA, Viral / metabolism
  • Signal Transduction
  • Toll-Like Receptor 3 / metabolism

Substances

  • Membrane Proteins
  • Nucleotide Transport Proteins
  • RNA, Double-Stranded
  • RNA, Viral
  • Sidt2 protein, mouse
  • Toll-Like Receptor 3
  • DEAD Box Protein 58