Axl Mediates ZIKA Virus Entry in Human Glial Cells and Modulates Innate Immune Responses

Publication date: 10 January 2017
Source:Cell Reports, Volume 18, Issue 2
Author(s): Laurent Meertens, Athena Labeau, Ophelie Dejarnac, Sara Cipriani, Laura Sinigaglia, Lucie Bonnet-Madin, Tifenn Le Charpentier, Mohamed Lamine Hafirassou, Alessia Zamborlini, Van-Mai Cao-Lormeau, Muriel Coulpier, Dorothée Missé, Nolwenn Jouvenet, Ray Tabibiazar, Pierre Gressens, Olivier Schwartz, Ali Amara
ZIKA virus (ZIKV) is an emerging pathogen responsible for neurological disorders and congenital microcephaly. However, the molecular basis for ZIKV neurotropism remains poorly understood. Here, we show that Axl is expressed in human microglia and astrocytes in the developing brain and that it mediates ZIKV infection of glial cells. Axl-mediated ZIKV entry requires the Axl ligand Gas6, which bridges ZIKV particles to glial cells. Following binding, ZIKV is internalized through clathrin-mediated endocytosis and traffics to Rab5+ endosomes to establish productive infection. During entry, the ZIKV/Gas6 complex activates Axl kinase activity, which downmodulates interferon signaling and facilitates infection. ZIKV infection of human glial cells is inhibited by MYD1, an engineered Axl decoy receptor, and by the Axl kinase inhibitor R428. Our results highlight the dual role of Axl during ZIKV infection of glial cells: promoting viral entry and modulating innate immune responses. Therefore, inhibiting Axl function may represent a potential target for future antiviral therapies.

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Teaser

ZIKA virus (ZIKV) is responsible for congenital microcephaly. Meertens et al. show that the Axl receptor is expressed in microglia and astrocytes in the human developing brain. They also highlight the dual role of Axl during infection, which promotes viral entry and dampens innate immune responses in glial cells.


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