Reevaluation of erythropoietin production by the nephron

Biochem Biophys Res Commun. 2014 Jun 27;449(2):222-8. doi: 10.1016/j.bbrc.2014.05.014. Epub 2014 May 14.


Erythropoietin production has been reported to occur in the peritubular interstitial fibroblasts in the kidney. Since the erythropoietin production in the nephron is controversial, we reevaluated the erythropoietin production in the kidney. We examined mRNA expressions of erythropoietin and HIF PHD2 using high-sensitive in situ hybridization system (ISH) and protein expression of HIF PHD2 using immunohistochemistry in the kidney. We further investigated the mechanism of erythropoietin production by hypoxia in vitro using human liver hepatocell (HepG2) and rat intercalated cell line (IN-IC cells). ISH in mice showed mRNA expression of erythropoietin in proximal convoluted tubules (PCTs), distal convoluted tubules (DCTs) and cortical collecting ducts (CCDs) but not in the peritubular cells under normal conditions. Hypoxia induced mRNA expression of erythropoietin largely in peritubular cells and slightly in PCTs, DCTs, and CCDs. Double staining with AQP3 or AE1 indicated that erythropoietin mRNA expresses mainly in β-intercalated or non α/non β-intercalated cells of the collecting ducts. Immunohistochemistry in rat showed the expression of HIF PHD2 in the collecting ducts and peritubular cells and its increase by anemia in peritubular cells. In IN-IC cells, hypoxia increased mRNA expression of erythropoietin, erythropoietin concentration in the medium and protein expression of HIF PHD2. These data suggest that erythropoietin is produced by the cortical nephrons mainly in the intercalated cells, but not in the peritubular cells, in normal hematopoietic condition and by mainly peritubular cells in hypoxia, suggesting the different regulation mechanism between the nephrons and peritubular cells.

Keywords: Anemia; Collecting duct; Erythropoietin; Hypoxia; Hypoxia-inducible factor; Nephron.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Hypoxia
  • Cell Line
  • Erythropoietin / biosynthesis*
  • Erythropoietin / genetics
  • Gene Expression Regulation
  • Hep G2 Cells
  • Humans
  • Hypoxia-Inducible Factor-Proline Dioxygenases / genetics
  • Hypoxia-Inducible Factor-Proline Dioxygenases / metabolism
  • Immunohistochemistry
  • In Situ Hybridization
  • Kidney / cytology
  • Kidney / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Nephrons / metabolism*
  • Procollagen-Proline Dioxygenase / genetics
  • Procollagen-Proline Dioxygenase / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Tissue Distribution


  • EPO protein, human
  • RNA, Messenger
  • Erythropoietin
  • Procollagen-Proline Dioxygenase
  • Egln1 protein, mouse
  • Egln1 protein, rat
  • Hypoxia-Inducible Factor-Proline Dioxygenases