Unraveling PPARβ/δ nuclear receptor agonists <i>via</i> a drug-repurposing approach: HTVS-based ligand identification, molecular dynamics, pharmacokinetics, and <i>in vitro</i> anti-steatotic validation

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated nuclear receptors with a crucial regulatory role in carbohydrate and lipid metabolism and are emerging druggable targets in "metabolic syndrome" (MetS) and cancers. However, there is a need to identify ligands that can activate specific PPAR subtypes, particularly PPARβ/δ, which is less studied compared with other PPAR isoforms (α and γ). Herein, using the drug-repurposing approach, the ZINC database of clinically approved drugs was screened to target the PPARβ/δ receptor through high-throughput-virtual-screening, followed by molecular docking and molecular dynamics (MD) simulation. The top-scoring ligands were subjected to drug-likeness analysis. The hit molecule was tested in an <i>in vitro</i> model of NAFLD (non-alcoholic fatty liver disease). The top five ligands with strong binding affinity towards PPARβ/δ were canagliflozin > empagliflozin > lumacaftor > eprosartan > dapagliflozin. RMSD/RMSF analysis demonstrated stable protein-ligand complexation (PLC) by the top-scoring ligands with PPARβ/δ. <i>In silico</i> ADMET prediction analysis revealed favorable pharmacokinetic profiles of these top five ligands. Canagliflozin showed significant (<i>P</i> < 0.001) dose-dependent decrease in lipid accumulation and the associated oxidative stress-inflammatory response, suggesting its promising anti-steatotic potential. These outcomes pave the way for further validation and development of PPAR activity-modulating therapeutics.