Combination Kinase Inhibitor Treatment Suppresses Rift Valley Fever Virus Replication

Area of Science:

• Virology
• Molecular Biology
• Drug Discovery

Background:

• Viruses hijack host cell translation machinery for replication.
• Kinases like p70 S6K, p90RSK, ERK, and p38 MAPK are activated during Rift Valley fever virus (RVFV) infection.
• Inhibiting p70 S6K with rapamycin reduces RVFV pathogenesis in mice.

Purpose of the Study:

• To investigate the efficacy of inhibiting multiple host cell kinases involved in translation against RVFV.
• To determine if combined kinase inhibition enhances antiviral effects compared to single-agent treatments.

Main Methods:

• Treatment of RVFV-infected cells/models with specific kinase inhibitors (PF-4708671, BI-D1870, SB203580, PD0325901) and rapamycin.
• Assessment of translational protein phosphorylation and viral titers.
• Evaluation of single and combination inhibitor treatment effects on viral replication.

Main Results:

• PF-4708671 treatment reduced RVFV titers and target protein phosphorylation.
• Single inhibitors targeting p90RSK, p38 MAPK, or ERK showed minimal impact on RVFV titers.
• Combination therapy of PF-4708671 with BI-D1870, or SB203580/PD0325901 with rapamycin, synergistically inhibited RVFV replication.

Conclusions:

• Targeting host cell translation machinery via kinase inhibition is a viable strategy against RVFV.
• Combination kinase inhibitor therapy demonstrates significant potential for treating RVFV infections.
• These findings provide a proof of concept for developing novel antiviral combination treatments.