Activation of Intestinal HIF2α Ameliorates Iron‐Refractory Anemia

Abstract In clinics, hepcidin levels are elevated in various anemia‐related conditions, particularly in iron‐refractory anemia and in high inflammatory states that suppress iron absorption, which remains an urgent unmet medical need. To identify effective treatment options for various types of iron‐refractory anemia, the potential effect of hypoxia and pharmacologically‐mimetic drug FG‐4592 (Roxadustat) are evaluated, a hypoxia‐inducible factor (HIF)‐prolyl hydroxylase (PHD) inhibitor, on mouse models of iron‐refractory iron‐deficiency anemia (IRIDA), anemia of inflammation and 5‐fluorouracil‐induced chemotherapy‐related anemia. The potent protective effects of both hypoxia and FG‐4592 on IRIDA as well as other 2 tested mouse cohorts are found. Mechanistically, it is demonstrated that hypoxia or FG‐4592 could stabilize duodenal Hif2α, leading to the activation of Fpn transcription regardless of hepcidin levels, which in turn results in increased intestinal iron absorption and the amelioration of hepcidin‐activated anemias. Moreover, duodenal Hif2α overexpression fully rescues phenotypes of Tmprss6 knockout mice, and Hif2α knockout in the gut significantly delays the recovery from 5‐fluorouracil‐induced anemia, which can not be rescued by FG‐4592 treatment. Taken together, the findings of this study provide compelling evidence that targeting intestinal hypoxia‐related pathways can serve as a potential therapeutic strategy for treating a broad spectrum of anemia, especially iron refractory anemia.