Proximal tubule H-ferritin mediates iron trafficking in acute kidney injury

J Clin Invest. 2013 Oct;123(10):4423-34. doi: 10.1172/JCI67867. Epub 2013 Sep 9.

Abstract

Ferritin plays a central role in iron metabolism and is made of 24 subunits of 2 types: heavy chain and light chain. The ferritin heavy chain (FtH) has ferroxidase activity that is required for iron incorporation and limiting toxicity. The purpose of this study was to investigate the role of FtH in acute kidney injury (AKI) and renal iron handling by using proximal tubule-specific FtH-knockout mice (FtH(PT-/-) mice). FtH(PT-/-) mice had significant mortality, worse structural and functional renal injury, and increased levels of apoptosis in rhabdomyolysis and cisplatin-induced AKI, despite significantly higher expression of heme oxygenase-1, an antioxidant and cytoprotective enzyme. While expression of divalent metal transporter-1 was unaffected, expression of ferroportin (FPN) was significantly lower under both basal and rhabdomyolysis-induced AKI in FtH(PT-/-) mice. Apical localization of FPN was disrupted after AKI to a diffuse cytosolic and basolateral pattern. FtH, regardless of iron content and ferroxidase activity, induced FPN. Interestingly, urinary levels of the iron acceptor proteins neutrophil gelatinase-associated lipocalin, hemopexin, and transferrin were increased in FtH(PT-/-) mice after AKI. These results underscore the protective role of FtH and reveal the critical role of proximal tubule FtH in iron trafficking in AKI.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Kidney Injury / chemically induced
  • Acute Kidney Injury / metabolism*
  • Animals
  • Apoferritins / metabolism*
  • Base Sequence
  • Biological Transport
  • Cation Transport Proteins / genetics
  • Cation Transport Proteins / metabolism
  • DNA Primers / genetics
  • Gene Expression Regulation
  • Genotyping Techniques
  • Iron / metabolism*
  • Kidney Tubules, Proximal / metabolism*
  • Kidney Tubules, Proximal / pathology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Rhabdomyolysis / metabolism

Substances

  • Cation Transport Proteins
  • DNA Primers
  • metal transporting protein 1
  • solute carrier family 11- (proton-coupled divalent metal ion transporters), member 2
  • Apoferritins
  • Iron