Format

Send to

Choose Destination
J Am Soc Nephrol. 2016 Sep;27(9):2720-32. doi: 10.1681/ASN.2015040461. Epub 2016 Jan 29.

Renal Handling of Circulating and Renal-Synthesized Hepcidin and Its Protective Effects against Hemoglobin-Mediated Kidney Injury.

Author information

1
Departments of Laboratory Medicine, Pharmacology and Toxicology, Rachel.vanSwelm@radboudumc.nl.
2
Nephrology, and.
3
Pharmacology and Toxicology.
4
Departments of Laboratory Medicine.
5
Physiology, Radboud University Medical Center, Nijmegen, The Netherlands;
6
Institute of Physiology, Pathophysiology and Toxicology, Center for Biomedical Training and Research, University of Witten/Herdecke, Witten, Germany; and.
7
Pharmacology and Toxicology, Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands.

Abstract

Urinary hepcidin may have protective effects against AKI. However, renal handling and the potential protective mechanisms of hepcidin are not fully understood. By measuring hepcidin levels in plasma and urine using mass spectrometry and the kidney using immunohistochemistry after intraperitoneal administration of human hepcidin-25 (hhep25) in C57Bl/6N mice, we showed that circulating hepcidin is filtered by the glomerulus and degraded to smaller isoforms detected in urine but not plasma. Moreover, hepcidin colocalized with the endocytic receptor megalin in proximal tubules, and compared with wild-type mice, megalin-deficient mice showed higher urinary excretion of injected hhep25 and no hepcidin staining in proximal tubules that lack megalin. This indicates that hepcidin is reaborbed in the proximal tubules by megalin dependent endocytosis. Administration of hhep25 concomitant with or 4 hours after a single intravenous dose of hemoglobin abolished hemoglobin-induced upregulation of urinary kidney injury markers (NGAL and KIM-1) and renal Interleukin-6 and Ngal mRNA observed 24 hours after administration but did not affect renal ferroportin expression at this point. Notably, coadministration of hhep25 and hemoglobin but not administration of either alone greatly increased renal mRNA expression of hepcidin-encoding Hamp1 and hepcidin staining in distal tubules. These findings suggest a role for locally synthesized hepcidin in renal protection. Our observations did not support a role for ferroportin in hhep25-mediated protection against hemoglobin-induced early injury, but other mechanisms of cellular iron handling may be involved. In conclusion, our data suggest that both systemically delivered and locally produced hepcidin protect against hemoglobin-induced AKI.

KEYWORDS:

acute kidney injury; hemoglobin; hepcidin; iron; megalin

PMID:
26825531
PMCID:
PMC5004644
DOI:
10.1681/ASN.2015040461
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center