A Synthetic ERRα Agonist Induces an Acute Aerobic Exercise Response and Enhances Exercise Capacity

This study investigated whether a synthetic small-molecule agonist of the orphan nuclear receptor ERRα (estrogen receptor-related receptor alpha), called SLU-PP-332, could mimic the genetic and physiological effects of aerobic exercise in skeletal muscle. Researchers first used cell-based assays to confirm that SLU-PP-332 activates ERRα and found it triggered an acute aerobic exercise-associated gene expression program in skeletal muscle cells in an ERRα-dependent manner. In cell culture experiments, the compound increased mitochondrial function and cellular respiration. When administered to mice, SLU-PP-332 was reported to increase the proportion of type IIa oxidative skeletal muscle fibers and improve exercise endurance capacity. The authors propose that ERRα is a viable pharmacological target for developing "exercise mimetic" compounds, which could potentially help treat metabolic disorders and age-related muscle decline. Key limitations include the preclinical (mouse and cell-based) nature of all findings, the absence of human data, and the preprint status of the paper, meaning it had not yet undergone formal peer review at the time of reporting. No conclusions about human efficacy or safety can be drawn from this work alone.

Why this grade: All experimental findings are derived from mouse models and in vitro cell assays, with no human subjects enrolled, and the paper was a preprint at the time of reporting.