1. HER2-mediated enhancement of Ebola virus entry.
- Author
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Kuroda, Makoto, Halfmann, Peter, and Kawaoka, Yoshihiro
- Subjects
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EBOLA virus , *EPIDERMAL growth factor receptors , *EBOLA virus disease , *PROTEIN-tyrosine kinases - Abstract
Multiple cell surface molecules including TAM receptors (TYRO3, AXL, and MERTK), a family of tyrosine kinase receptors, can serve as attachment receptors for Ebola virus (EBOV) entry into cells. The interaction of these receptors with EBOV particles is believed to trigger the initial internalization events that lead to macropinocytosis. However, the details of how these interactions lead to EBOV internalization have yet to be elucidated. Here, we screened receptor tyrosine kinase (RTK) inhibitors for anti-EBOV activity by using our previously established biologically contained Ebola virus that lacks the VP30 gene (EBOVΔVP30) and identified several RTKs, including human epidermal growth factor receptor 2 (HER2), as potential targets of anti-EBOV inhibitors and as novel host factors that have a role in EBOV infection. Of these identified RTKs, it was only HER2 whose knockdown by siRNAs impaired EBOVΔVP30-induced AKT1 phosphorylation, an event that is required for AKT1 activation and subsequent macropinocytosis. Stable expression of HER2 resulted in constitutive activation of AKT1, resulting in the enhancement of EBOVΔVP30 growth, EBOV GP-mediated entry, and macropinocytosis. Moreover, we found that HER2 interacts with the TAM receptors, and in particular forms a complex with TYRO3 and EBOVΔVP30 particles on the cell surface. Interestingly, HER2 was required for EBOVΔVP30-induced TYRO3 and AKT1 activation, but the other TAM receptors (TYRO3 and MERTK) were not essential for EBOVΔVP30-induced HER2 and AKT1 activation. Our findings demonstrate that HER2 plays an important role in EBOV entry and provide novel insights for the development of therapeutics against the virus. Author summary: Ebola virus disease is a global threat to human health as seen during the 2013–2016 outbreak in West Africa and the on-going outbreak in the Democratic Republic of the Congo. Currently, there are no approved therapeutics for patient treatment; although, recent monoclonal antibody therapeutic treatments have been used during the current outbreak, despite their lack of efficacy in the later stage of infection. Here, we screened a library of receptor tyrosine kinase inhibitors for anti-Ebola virus activity and identified five compounds that significantly attenuated Ebola virus growth in cell culture mediated not only by the Ebola virus GP but also by other filovirus GPs. Further investigation focusing on the role of human epidermal growth factor receptor 2 (HER2), the cellular target of two of these inhibitors, in Ebola virus cell entry revealed that HER2 interacts with TAM (TYRO3, AXL, and MERTK) receptors and mediates Ebola virus-induced TYRO3 and AKT1 activation that leads to the initiation of macropinocytic uptake of viral particles into cells. Our findings provide new insights into the mechanism underlying Ebola virus entry, which will be of value to the development of novel therapeutics against the virus. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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