Cell Surface Vimentin Is an Attachment Factor That Facilitates Equine Arteritis Virus Infection In Vitro

Area of Science:

• Virology
• Cell Biology
• Protein Interactions

Background:

• Equine arteritis virus (EAV) exhibits broad host cell tropism, infecting cells beyond those expressing the known receptor, equine CXCL16 (EqCXCL16S).
• This suggests EAV utilizes additional host cell proteins to facilitate infection and explain its diverse cellular targets.

Purpose of the Study:

• To identify other host cell proteins that interact with EAV and contribute to its infection.
• To investigate the role of vimentin as a potential EAV entry factor.

Main Methods:

• Virus overlay protein-binding assay and Far-Western blot were used to identify EAV-binding proteins in equine cells.
• Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was employed for protein identification.
• Vimentin's role was assessed through cell line screening, antibody neutralization, and gene overexpression studies.

Main Results:

• A 57 kDa membrane protein was identified as a potential EAV-binding protein and subsequently identified as vimentin via LC-MS/MS.
• EAV infection susceptibility correlated with vimentin expression across various mammalian cell lines.
• Anti-vimentin antibody and Withaferin A partially inhibited EAV infection, while vimentin overexpression enhanced it.

Conclusions:

• Equine vimentin acts as an attachment factor for EAV, actively participating in the infection process.
• EAV employs multiple host cell proteins, including vimentin, to achieve its broad cell tropism.
• This finding provides new insights into EAV-host interactions and viral entry mechanisms.