Chemical optimization of the exercise mimetic SLU-PP-332 enables insight into estrogen-related receptor signaling

Estrogen-related receptors (ERRs) are master regulators of mitochondrial metabolism and exercise-responsive transcription, yet only a limited number of synthetic agonists with suitable potency and drug-like properties have been reported. SLU-PP-332 is a well-established exercise mimetic and widely used chemical probe for ERR activation; however, the structural features governing its potency, efficacy, selectivity, and drug-like properties have not been systematically elucidated. Here, we report the first comprehensive structure-activity relationship (SAR) analysis of the SLU-PP-332 scaffold, integrating chemical synthesis, cell-based functional assays, downstream gene-expression profiling, and computational modeling. Through iterative modification of core pharmacophoric elements, we identify key structural determinants that control ERRα and ERRγ agonism, transcriptional efficacy, ligand efficiency, and physicochemical properties. While SLU-PP-332 remains a strong benchmark for ERR activation, several analogues achieve comparable or context-dependent transcriptional responses while exhibiting improved ligand efficiency, solubility, or metabolic stability. Computational docking and molecular dynamics simulations reveal how subtle structural modifications influence ERR engagement and signaling outcomes. Together, this work defines design principles for tuning ERR agonism and provides a foundational SAR roadmap for the rational development of next-generation ERR agonists and exercise-mimetic therapeutics.