The hepcidin regulator erythroferrone is a new member of the erythropoiesis-iron-bone circuitry
Abstract
Background: Erythroblast erythroferrone (ERFE) secretion inhibits hepcidin expression by sequestering several bone morphogenetic protein (BMP) family members to increase iron availability for erythropoiesis.
Methods: To address whether ERFE functions also in bone and whether the mechanism of ERFE action in bone involves BMPs, we utilize the Erfe-/- mouse model as well as β–thalassemic (Hbbth3/+) mice with systemic loss of ERFE expression. In additional, we employ comprehensive skeletal phenotyping analyses as well as functional assays in vitro to address mechanistically the function of ERFE in bone.
Results: We report that ERFE expression in osteoblasts is higher compared with erythroblasts, is independent of erythropoietin, and functional in suppressing hepatocyte hepcidin expression. Erfe-/- mice display low–bone–mass arising from increased bone resorption despite a concomitant increase in bone formation. Consistently, Erfe-/- osteoblasts exhibit enhanced mineralization, Sost and Rankl expression, and BMP–mediated signaling ex vivo. The ERFE effect on osteoclasts is mediated through increased osteoblastic RANKL and sclerostin expression, increasing osteoclastogenesis in Erfe-/- mice. Importantly, Erfe loss in Hbbth3/+ mice, a disease model with increased ERFE expression, triggers profound osteoclastic bone resorption and bone loss.
Conclusions: Together, ERFE exerts an osteoprotective effect by modulating BMP signaling in osteoblasts, decreasing RANKL production to limit osteoclastogenesis, and prevents excessive bone loss during expanded erythropoiesis in β–thalassemia.
Funding: Y.Z.G. acknowledges the support of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) (R01 DK107670 to Y.Z.G. and DK095112 to R.F., S.R., and Y.Z.G.). M.Z. acknowledges the support of the National Institute on Aging (U19 AG60917) and NIDDK (R01 DK113627). T.Y. acknowledges the support of the National Institute on Aging (R01 AG71870). S.R. acknowledges the support of NIDDK (R01 DK090554) and Commonwealth Universal Research Enhancement (C.U.R.E.) Program Pennsylvania.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files.
Article and author information
Author details
Funding
National Institute of Diabetes and Digestive and Kidney Diseases (DK107670)
- Yelena Ginzburg
National Institute of Diabetes and Digestive and Kidney Diseases (DK095112)
- Robert Fleming
- Stefano Rivella
- Yelena Ginzburg
National Institute of Diabetes and Digestive and Kidney Diseases (DK113627)
- Mone Zaidi
National Institute on Aging (AG60917)
- Mone Zaidi
National Institute of Diabetes and Digestive and Kidney Diseases (DK09055)
- Stefano Rivella
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All of the animals were handled according to approved institutional animal care and use committee (IACUC) protocols (#16-0143) of the Icahn School of Medicine.
Copyright
© 2021, Castro-Mollo et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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