High-throughput screening reveals paeoniflorin's efficacy against Apoc2-deficient hypertriglyceridemia via HNF4A/PPARA/LDLR.

Hypertriglyceridemia (HTG) is a significant risk factor for cardiovascular disease, fatty liver, and acute pancreatitis, yet remains a therapeutic challenge due to limitations of current treatment options. To address this unmet clinical need, we screened a natural small-molecule library at an initial concentration of 100 μM to identify effective HTG therapeutic candidates using a CRISPR/Cas9-generated apolipoprotein C2 (apoc2) knockout zebrafish model that resembles human lipid metabolism disorders. Phenotype-based screening identified paeoniflorin (PAE) from 351 compounds as a potent triglyceride-lowering agent. Lipidomics analysis revealed PAE promoted triglyceride lipolysis by β-oxidation and lipophagy. Mechanistic studies demonstrated PAE upregulates peroxisome proliferator-activated receptor α (ppara) and lipoprotein receptor (ldlr) in apoc2 mutants. In oleic acid-induced Huh7 human hepatocytes, PAE reduces intracellular lipid droplet accumulation and significantly upregulated PPARA and LDLR expression, indicating enhanced hepatocellular uptake and oxidative catabolism of triglyceride-rich lipoproteins. Further investigation revealed that PAE upregulates the expression of hepatocyte nuclear factor 4 α (HNF4A), a key upstream transcription factor of PPARA. The HNF4A inhibitor BI-6015 completely abolished PAE's triglyceride-lowering effects, suggesting mediation through the HNF4A-PPARA-LDLR axis. These findings establish PAE as a promising therapeutic candidate for HTG through a novel mechanism targeting the HNF4A-PPARA-LDLR pathway. Our work not only identifies a potential lead compound for HTG treatment but also supports the zebrafish model as an effective platform for discovering drugs targeting hepatic lipid metabolic pathways.