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

AMP-activated protein kinase (AMPK) plays a central role in regulating cell energy balance. When activated, AMPK suppresses energy-consuming pathways, such as lipid and protein synthesis, while increasing nutrient availability through the activation of autophagy. These pathways downstream of 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 reduced lipid metabolism, which affected viral factories. Furthermore, MK-8722 treatment increased the type I interferon (IFN-I) response. Post-infection treatment with MK-8722 was enough to inhibit efficient 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. IMPORTANCE: Coronavirus disease 2019, caused by SARS-CoV-2 infection, has led to severe acute respiratory syndrome with very high mortality. Despite available vaccines and public health measures, new SARS-CoV-2 variants emerge with increased transmissibility requiring the development of novel therapeutic strategies. Recently, the AMP-activated protein kinase (AMPK), a cellular energy sensor, has emerged as a potential broad-spectrum antiviral target, as AMPK can modulate the intracellular environment in turn impeding viral replication. This study aims to evaluate the potential of pharmacological activation of AMPK to inhibit SARS-CoV-2 infection and replication. Our findings demonstrate that AMPK activation induces significant alterations in host cellular lipid metabolism that disrupt viral factories essential for SARS-CoV-2 replication. Furthermore, by enhancing autophagy, a process crucial for the degradation and clearance of viral particles, AMPK activation facilitates the elimination of the virus. Therefore, targeting AMPK signaling pathways could offer a promising therapeutic approach for the treatment of SARS-CoV-2 infections.