Abstract
ibroblast growth factor–23 (FGF-23) interacts with a binary receptor complex composed of a-Klotho (a-KL) and FGF receptors (FGFRs) to regulate phosphate and vitamin D metabolism in the kidney. Excess FGF-23 production, which causes hypophosphatemia, is genetically inherited or occurs with chronic kidney disease. Among other symp-toms, hypophosphatemia causes vitamin D deficiency and the bone-softening disorder rickets. Current therapeutics that target the receptor complex have limited utility clinically. Using a computationally driven, structure-based, en-semble docking and virtual high-throughput screening approach, we identified four novel compounds predicted to selectively inhibit FGF-23–induced activation of the FGFR/a-KL complex. Additional modeling and functional analysis found that Zinc13407541 bound to FGF-23 and disrupted its interaction with the FGFR1/a-KL complex; experiments in a heterologous cell expression system showed that Zinc13407541 selectivity inhibited a-KL–dependent FGF-23 signaling. Zinc13407541 also inhibited FGF-23 signaling in isolated renal tubules ex vivo and partially reversed the hypophosphatemic effects of excess FGF-23 in a mouse model. These chemical probes provide a platform to devel-op lead compounds to treat disorders caused by excess FGF-23.
