Modulation of estrogen-related receptors subtype selectivity: Conversion of an ERRβ/γ selective agonist to ERRα/β/γ pan agonists

Estrogen Related Receptors (ERRs) are key regulators of energy homeostasis and play important role in the etiology of metabolic disorders, skeletal muscle related disorders, and neurodegenerative diseases. Among the three ERR isoforms, ERR alpha emerged as a potential drug target for metabolic and neurodegenerative diseases. Although ERR beta/gamma selective agonist chemical tools have been identified, there are no chemical tools that effectively target ERR alpha agonism. We successfully engineered high affinity ERR alpha agonism into a chemical scaffold that displays selective ERR beta/gamma agonist activity (GSK4716), providing novel ERR alpha/beta/gamma pan agonists that can be used as tools to probe the physiological roles of these nuclear receptors. We identified the structural requirements to enhance selectivity toward ERR alpha. Molecular modeling shows that our novel modulators have favorable binding modes in the LBP of ERR alpha and can induce conformational changes where Phe328 that originally occupies the pocket is dislocated to accommodate the ligands in a rather small cavity. The best agonists up-regulated the expression of target genes PGC-1 alpha and PGC-1 beta, which are necessary to achieve maximal mitochondrial biogenesis. Moreover, they increased the mRNA levels of PDK4, which play an important role in energy homeostasis.