Lipid metabolism plays a crucial role in cellular signal transduction, affects the structural integrity of cell membranes, and regulates energy metabolism. However, various viruses, including African swine fever virus (ASFV), usurp lipid metabolism to enhance their replication. The mechanism for the positive role of lipid metabolism in ASFV infection is unclear. Here, we present data that ASFV infection concurrently upregulates both fatty acid synthesis (FAS) and fatty acid β-oxidation (FAO) to enhance viral replication. Pharmacological inhibition of FAS significantly suppresses ASFV replication, an effect that can be markedly reversed by exogenous palmitate (the end product of FAS). Similarly, inhibition of FAO also impairs viral replication. Lipidomic profiling revealed that ASFV infection dramatically alters lipid droplet (LD) lipid composition, particularly triglycerides (TG) and diacylglycerols (DAG). ASFV infection triggers the accumulation of LDs, which in turn promote viral replication. Mechanistically, we discovered that ASFV exploits chaperone-mediated autophagy (CMA) to degrade perilipin 2 (PLIN2), a protein on the LD surface, thereby stimulating lipolysis. Furthermore, ASFV infection induces LD-mitochondrion contacts, facilitating the transfer of LD-derived fatty acids to mitochondria. These data indicate that LDs provide lipids to fuel ASFV-induced FAO upregulation. Collectively, our study reveals that ASFV orchestrates a complex metabolic network involving FAS, LD biogenesis, lipolysis, and FAO to optimize viral replication. These findings elucidate the pivotal role of lipid metabolism in ASFV replication, revealing a mechanism through which the virus manipulates cellular lipid pathways to facilitate its replication. This insight not only advances our understanding of ASFV pathogenesis but also presents potential therapeutic avenues for inhibiting viral production by modulating lipid metabolic processes.IMPORTANCEAfrican swine fever (ASF), caused by African swine fever virus (ASFV), represents a catastrophic threat to the global swine industry, with no safe and effective vaccines or antiviral therapies currently available except in Vietnam. Understanding how ASFV reprograms host lipid metabolism is critical for developing targeted interventions. Our study reveals a novel metabolic hijacking strategy employed by ASFV to reprogram lipid metabolism pathways, including fatty acid synthesis (FAS), lipid droplet (LD) biogenesis, chaperone-mediated autophagy (CMA)-mediated lipolysis, and mitochondrial β-oxidation (FAO), to support viral replication. Notably, we provide evidence that ASFV exploits CMA to degrade perilipin 2 (PLIN2), a key protein stabilizing lipid droplets, thereby promoting lipolysis. This mechanism resolves the paradox of concurrent upregulation of FAS and FAO by facilitating lipid shuttling through LD-mitochondrion contacts. Our findings offer new insights into how ASFV exploits host lipid networks and may pave the way for designing vaccines or targeted drugs to control ASF.
Yang et al. (Mon,) studied this question.