FGF23 expression in rodents is directly induced via erythropoietin after inhibition of hypoxia inducible factor proline hydroxylase

PLoS One. 2017 Oct 26;12(10):e0186979. doi: 10.1371/journal.pone.0186979. eCollection 2017.

Abstract

Plasma levels of FGF23 are increased in patients with chronic kidney disease. Beside its role in phosphate homeostasis, iron deficiency and anemia are associated with increased FGF23 plasma levels. Recently, FGF23 plasma levels were shown to be increased in mice after treatment with hypoxia inducible factor-proline hydroxylase (HIF-PH) inhibitors which are strong inducers of erythropoietin and erythropoiesis and are known to modulate iron uptake and availability. Therefore we investigated a potential context between expression of FGF23 and stimulation of erythropoiesis using a HIF-PH inhibitor and erythropoietin in rats. FGF23 plasma levels are induced at peak levels 2 h after intravenous injection of recombinant human Erythropoietin (rhEPO). Likewise induction of endogenous EPO using a HIF-PH inhibitor (BAY 85-3934) is followed by an increase of FGF23 plasma levels. In contrast to rhEPO the HIF-PH inhibitor induces lower peak levels of FGF23 applying equivalent hematopoietic doses. Bone and bone marrow were identified as sources of EPO-induced FGF23. Immediate induction of FGF23 mRNA was also detected in EPO receptor positive murine hematopoietic BAF3 cells after treatment with rhEPO but not after treatment with the HIF-PH inhibitor. Pretreatment of mice with a neutralizing anti-EPO antibody abrogated FGF23 induction by the HIF-PH inhibitor. Thus, direct impact on FGF23 expression by HIF-PH inhibition in vivo via hypoxia mimicking and modulation of iron metabolism appears unlikely. Collectively, the findings point to an EPO dependent regulation pathway of FGF23 gene expression which might be important in the context of erythropoiesis stimulating therapies in patients with renal anemia.

MeSH terms

  • Animals
  • Enzyme Inhibitors / pharmacology*
  • Erythropoietin / pharmacology*
  • Fibroblast Growth Factor-23
  • Fibroblast Growth Factors / genetics*
  • Gene Expression Regulation / drug effects*
  • Humans
  • Hypoxia-Inducible Factor-Proline Dioxygenases / antagonists & inhibitors*
  • Male
  • Mice
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rats

Substances

  • Enzyme Inhibitors
  • FGF23 protein, human
  • Fgf23 protein, mouse
  • Fgf23 protein, rat
  • RNA, Messenger
  • Erythropoietin
  • Fibroblast Growth Factors
  • Fibroblast Growth Factor-23
  • Hypoxia-Inducible Factor-Proline Dioxygenases

Grants and funding

This study was funded by Bayer AG. All the authors are employees of Bayer AG. Bayer AG provided support in the form of salaries for all authors, and played a role in the study design, data collection and analysis, decision to publish and preparation of the manuscript. The specific roles of all authors are articulated in the ‘author contributions’ section.