Uncovering the Vital Role of Lipid Droplets in Coronavirus Replication: A Novel Insight Arising from the Biological Activity of 2-Bromopalmitate

The emergence of viral infections with global impact highlights the urgent need for broad-spectrum antivirals. In this study, we evaluated the effect of palmitoylation inhibitors [2-bromopalmitate (2-BP), cerulenin, and 2-fluoro palmitic acid (2-FPA)] and the enhancer palmostatin B on the replication of human coronaviruses (hCoV-229E, hCoV-Oc43) and murine hepatitis virus (MHV-A59) at non-cytotoxic concentrations. The results demonstrated that 2-BP strongly suppressed MHV-A59 replication, while cerulenin and 2-FPA only moderately inhibited viral replication. Palmostatin B significantly enhanced viral replication. Notably, 2-BP exhibited superior efficacy. Interestingly, palmostatin B failed to rescue the inhibitory effects of 2-BP but effectively rescued cerulenin and 2-FPA, suggesting additional biological activities of 2-BP beyond palmitoylation inhibition. Furthermore, we discovered that 2-BP specifically disrupted lipid droplets (LDs), and this LD disruption was correlated with viral replication inhibition. Based on our findings, we conclude that the inhibitory effects of 2-BP on viral replication primarily stem from LD disruption rather than palmitoylation inhibition. Therefore, we revealed the crucial role of LDs in the viral replication. Our study provides insights into the development of wide-spectrum antiviral strategies.