Mechanistic role of lipid metabolism in foot-and-mouth disease virus (FMDV) replication

Figure 1. The effect of ACC on FMDV replication. A Research pathway map for de novo fatty acid synthesis. B BHK-21 cells were treated with 30 μM TOFA, 60 μM malonyl‑CoA, or 30 μM TOFA plus 60 μM malonyl‑CoA. After fixation, cells were stained with Nile red, and nuclei were labeled with DAPI (blue). Scale bar, 20 µm. C BHK-21 cells were treated with 5–45 μM TOFA for 24 h, and cell viability was not significantly affected. D Cytopathic effect (CPE) following FMDV infection in the presence of increasing concentrations of TOFA. E RT–qPCR confirmed that TOFA treatment inhibits FMDV replication. F Western blot analysis confirmed that TOFA treatment suppresses FMDV replication. G TOFA inhibited FMDV replication by 50% (EC50) at 21.33 μM. H CP640186 inhibited FMDV replication by 50% (EC50) at 0.2021 μM. I Viral plaque assay demonstrated that TOFA treatment significantly reduces FMDV replication. J BHK-21 cells were treated with 5–120 μM malonyl‑CoA for 24 h, and cell viability was not substantially affected. K RT–qPCR showed that, in the presence of 15 μM TOFA, supplementation with 0–45 μM malonyl‑CoA partially restored FMDV replication. L Western blot analysis confirmed that, in the presence of…

Figure 2. The effect of FASN on FMDV replication. A BHK-21 cells were treated with 30 μM C75, 75 μM palmitic acid, or 30 μM C75 plus 75 μM palmitic acid. After fixation, cells were stained with Nile red. Scale bar, 20 µm. B BHK-21 cells were treated with 5–45 μM C75 for 24 h, and cell viability was not significantly affected. C Cytopathic effect (CPE) following FMDV infection in the presence of increasing concentrations of C75. D RT–qPCR confirmed that C75 treatment inhibits FMDV replication. E Western blot analysis verified that C75 treatment suppresses the expression of FMDV VP1 protein. F Combined treatment with 10 μM C75 and TOFA exerted a stronger inhibitory effect on FMDV replication. G Viral plaque assay demonstrated that C75 treatment significantly inhibits FMDV replication. H BHK-21 cells were treated with 5–75 μM palmitic acid for 24 h, and cell viability was not substantially affected. I RT–qPCR showed that, in the presence of 30 μM C75, supplementation with 0–75 μM palmitic acid partially restored FMDV replication. J Western blot analysis confirmed that, in the presence of 45 μM C75, addition of 75 μM palmitic acid partially rescued FMDV VP1 protein expression. K BHK-21 cells…

Figure 3. The effect of LDs on FMDV replication. A BHK-21 cells were treated with 30 μM A922500, 60 μM oleic acid, or 30 μM A922500 plus 60 μM oleic acid. After fixation, cells were stained with Nile red. Scale bar, 20 µm. B BHK-21 cells were treated with 5–60 μM A922500 for 24 h, and cell viability was not significantly affected. C Cytopathic effect (CPE) following FMDV infection in the presence of increasing concentrations of A922500. D A922500 inhibited FMDV replication by 50% (EC50) at 11.86 μM. E RT–qPCR confirmed that A922500 treatment inhibits FMDV replication. F Western blot analysis verified that A922500 treatment suppresses FMDV VP1 protein expression. G Viral plaque assay demonstrated that A922500 treatment significantly inhibits FMDV replication. H BHK-21 cells were treated with 5–120 μM oleic acid for 24 h, and cell viability was not substantially affected. I RT–qPCR showed that, in the presence of 15 μM A922500, supplementation with 0–75 μM oleic acid partially restored FMDV replication. J Western blot analysis confirmed that, in the presence of 45 μM A922500, addition of 60 μM oleic acid partially rescued FMDV VP1 protein expression.

Figure 4. The effect of CPT1A on FMDV replication. A The expression of CPT1A was significantly upregulated after FMDV infection. B, C BHK-21 cells were treated with 60 μM Etomoxir. After fixation, cells were stained with Nile red, and nuclei were labeled with DAPI (blue). Scale bar, 20 µm. D BHK-21 cells were treated with 5–120 μM Etomoxir for 24 h, and cell viability was not significantly affected. E Cytopathic effect (CPE) following FMDV infection in the presence of increasing concentrations of Etomoxir. F RT–qPCR confirmed that Etomoxir treatment inhibits FMDV replication. G Western blot analysis verified that Etomoxir treatment suppresses FMDV replication. H Viral plaque assay demonstrated that Etomoxir treatment significantly inhibits FMDV replication.

Figure 5. Utilization of the lipid metabolism model during FMDV infection. ACC catalyzes the carboxylation of acetyl-CoA to generate malonyl-CoA; malonyl-CoA and acetyl-CoA are catalyzed by FASN to produce fatty acids; fatty acids are catalyzed by DGAT-1 to form triglycerides, which are stored in LDs; the degradation of LDs generates a large amount of FFAs, which are transported into mitochondria under the action of CPT1A to participate in β-oxidation for ATP production.