Discovery and characterization of a novel HIF-2α agonist for the treatment of CKD-related renal anemia

Hypoxia-inducible factor 2-alpha (HIF-2α), a critical transcription factor, forms a heterodimer with Aryl Hydrocarbon Receptor nuclear translocator (ARNT) to drive the transcription of erythropoietin (EPO), a key regulator of erythropoiesis. Activation of this pathway plays a pivotal role in the treatment of anemia. By discovered structure-based virtual screening and pharmacological assays, we herein discovered an amide thiazole AT-1 that bound to HIF-2α with a K_D of 2.63 μM, and enhanced the stability of the HIF-2α-ARNT heterodimer. Molecular docking and site-directed mutagenesis analysis revealed the critical roles of His293 and Tyr307 in the binding of AT-1 to HIF-2α. Pharmacological studies showed that AT-1 (10, 20, 40 μM) dose-dependently enhanced both the transcription and secretion of EPO in 786-O and Hep3B cells. In zebrafish (Danio rerio), AT-1 (10 or 50 μM) exhibited favorable safety profiles and, when combined with the prolyl hydroxylase (PHD) inhibitor Molidustat (10 μM), effectively mitigated doxorubicin-induced anemia. In adenine-induced chronic kidney disease (CKD) mouse model, combined administration of AT-1 (50 mg·kg^-1·d^-1, i.p.) and Molidustat (10 mg·kg^-1·d^-1, i.p.) for 15 days produced stronger effects on increasing EPO levels and alleviating anemia than Molidustat alone, further supporting the therapeutic potential of AT-1 in CKD-related anemia.