Marburgvirus Hijacks Nrf2-Dependent Pathway by Targeting Nrf2-Negative Regulator Keap1

• MARV VP24 binds Keap1 via the Kelch domain
• VP24 releases Nrf2 from control by its negative regulator, Keap1
• VP24 acts as an activator of the Nrf2-dependent antioxidant response pathway
• Nrf2 knockout mice control MARV replication when compared with wild-type animals

SummaryMarburg virus (MARV) has a high fatality rate in humans, causing hemorrhagic fever characterized by massive viral replication and dysregulated inflammation. Here, we demonstrate that VP24 of MARV binds Kelch-like ECH-associated protein 1 (Keap1), a negative regulator of nuclear transcription factor erythroid-derived 2 (Nrf2). Binding of VP24 to Keap1 Kelch domain releases Nrf2 from Keap1-mediated inhibition promoting persistent activation of a panoply of cytoprotective genes implicated in cellular responses to oxidative stress and regulation of inflammatory responses. Increased expression of Nrf2-dependent genes was demonstrated both during MARV infection and upon ectopic expression of MARV VP24. We also show that Nrf2-deficient mice can control MARV infection when compared to lethal infection in wild-type animals, indicating that Nrf2 is critical for MARV infection. We conclude that VP24-driven activation of the Nrf2-dependent pathway is likely to contribute to dysregulation of host antiviral inflammatory responses and that it ensures survival of MARV-infected cells despite these responses.

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