Direct pharmacological AMPK activation inhibits mucosal SARS-CoV-2 infection by reducing lipid metabolism, restoring autophagy flux and the type I IFN response

Abstract

AMP-activated protein kinase (AMPK) plays a central role in regulating cell energy balance. When activated, AMPK supresses energy-consuming pathways such as lipid and protein synthesis while increasing nutrient availability through the activation of autophagy. These pathways downstream AMPK activation contribute to SARS-CoV-2 infection, which hijacks autophagy and accumulates lipid droplets in viral factories to support viral replication. Here, we assessed the antiviral activity of the direct pan-AMPK allosteric activator MK-8722 in vitro. MK-8722 efficiently inhibited infection of Alpha and Omicron SARS-CoV-2 variants in Vero76 and human bronchial epithelial Calu-3 cells at micromolar concentration. This inhibition relied on restoring the autophagic flux, which redirected newly synthesized viral proteins for degradation, and on a reduction in lipid metabolism, which affected the viral factories. Furthermore, MK-8722 treatment increased the type I interferon (IFN-I) response. Post-infection treatment with MK-8722 was enough to inhibit efficiently viral replication and restore the IFN-I response. Finally, MK-8722 treatment did not alter the SARS-CoV-2-specific CD8+ T cell response mounted upon Spike vaccination. Overall, by activating AMPK, MK-8722 acts as an effective antiviral against SARS-CoV-2 infection, even when applied post-exposure, paving the way for preclinical tests aimed at inhibiting viral replication and improving patients' symptoms.