AXL promotes Zika virus infection in astrocytes by antagonizing type I interferon signalling

Nat Microbiol. 2018 Mar;3(3):302-309. doi: 10.1038/s41564-017-0092-4. Epub 2018 Jan 29.

Abstract

Zika virus (ZIKV) is associated with neonatal microcephaly and Guillain-Barré syndrome1,2. While progress has been made in understanding the causal link between ZIKV infection and microcephaly3-9, the life cycle and pathogenesis of ZIKV are less well understood. In particular, there are conflicting reports on the role of AXL, a TAM family kinase receptor that was initially described as the entry receptor for ZIKV10-22. Here, we show that while genetic ablation of AXL protected primary human astrocytes and astrocytoma cell lines from ZIKV infection, AXL knockout did not block the entry of ZIKV. We found, instead, that the presence of AXL attenuated the ZIKV-induced activation of type I interferon (IFN) signalling genes, including several type I IFNs and IFN-stimulating genes. Knocking out type I IFN receptor α chain (IFNAR1) restored the vulnerability of AXL knockout astrocytes to ZIKV infection. Further experiments suggested that AXL regulates the expression of SOCS1, a known type I IFN signalling suppressor, in a STAT1/STAT2-dependent manner. Collectively, our results demonstrate that AXL is unlikely to function as an entry receptor for ZIKV and may instead promote ZIKV infection in human astrocytes by antagonizing type I IFN signalling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Astrocytes / immunology
  • Astrocytes / virology*
  • Axl Receptor Tyrosine Kinase
  • Cell Line
  • Cells, Cultured
  • Gene Expression Regulation
  • Gene Knockout Techniques
  • Humans
  • Interferon Type I / immunology*
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / immunology*
  • Receptor Protein-Tyrosine Kinases / genetics
  • Receptor Protein-Tyrosine Kinases / immunology*
  • Receptor, Interferon alpha-beta / genetics
  • STAT1 Transcription Factor / genetics
  • STAT1 Transcription Factor / metabolism
  • Signal Transduction*
  • Suppressor of Cytokine Signaling 1 Protein / genetics
  • Suppressor of Cytokine Signaling 1 Protein / metabolism
  • Zika Virus / pathogenicity*

Substances

  • IFNAR1 protein, human
  • Interferon Type I
  • Proto-Oncogene Proteins
  • SOCS1 protein, human
  • STAT1 Transcription Factor
  • STAT1 protein, human
  • Suppressor of Cytokine Signaling 1 Protein
  • Receptor, Interferon alpha-beta
  • Receptor Protein-Tyrosine Kinases
  • Axl Receptor Tyrosine Kinase