Structure-Based Optimization of HIF-2α Agonists That Synergistically Enhance Erythropoietin Production with PHD Inhibitors

Hypoxia-inducible factor 2α (HIF-2α) is a crucial transcription factor regulating various physiological processes, including angiogenesis and erythropoiesis. The activity of HIF-2α is mainly controlled through oxygen-dependent protein hydroxylation, mediated by prolyl hydroxylase domain (PHD) enzymes, leading to subsequent HIF-2α ubiquitination and degradation. While several small-molecule PHD inhibitors have already been clinically applied in renal anemia treatment by indirectly activating the HIF-2α pathway, direct HIF-2α agonists remain largely unexplored. Here, we developed derivatives of HIF-2α agonist M1001, identifying SD-10 through molecular/cellular evaluations. By determining its cocrystal structure with the heterodimeric HIF-2 protein complex, we precisely characterized its molecular mechanism of action. Notably, SD-10 exhibited remarkable synergy with Daprodustat, an approved PHD inhibitor, in stimulating erythropoietin (EPO) secretion both in cellular models and animal studies. These findings not only provide insights into HIF-2α activation mechanism, but also offer a promising lead compound for developing innovative treatments for renal anemia.