Regulation of serum 1,25(OH)2vitamin D3 levels by fibroblast growth factor 23 is mediated by FGF receptors 3 and 4

Jyothsna Gattineni, Katherine Twombley, Regina Goetz, Moosa Mohammadi, Michel Baum

Research output: Contribution to journalArticlepeer-review

65 Scopus citations

Abstract

Fibroblast growth factor 23 (FGF23) is a phosphaturic hormone implicated in the pathogenesis of several hypophosphatemic disorders. FGF23 causes hypophosphatemia by decreasing the expression of sodium phosphate cotransporters (NaPi-2a and NaPi-2c) and decreasing serum 1,25(OH)2Vitamin D3 levels. We previously showed that FGFR1 is the predominant receptor for the hypophosphatemic actions of FGF23 by decreasing renal NaPi-2a and 2c expression while the receptors regulating 1,25(OH)2Vitamin D3 levels remained elusive. To determine the FGFRs regulating 1,25(OH)2Vitamin D3 levels, we studied FGFR3-/-FGFR4-/- mice as these mice have shortened life span and are growth retarded similar to FGF23-/- and Klotho-/- mice. Baseline serum 1,25(OH)2Vitamin D3 levels were elevated in the FGFR3-/-FGFR4-/- mice compared with wild-type mice (102.2 ± 14.8 vs. 266.0 ± 34.0 pmol/l; P = 0.001) as were the serum levels of FGF23. Administration of recombinant FGF23 had no effect on serum 1,25(OH)2Vitamin D3 in the FGFR3-/-FGFR4-/- mice (173.4 ± 32.7 vs. 219.7 ± 56.5 pmol/l; vehicle vs. FGF23) while it reduced serum 1,25(OH)2Vitamin D3 levels in wild-type mice. Administration of FGF23 to FGFR3-/-FGFR4-/- mice resulted in a decrease in serum parathyroid hormone (PTH) levels and an increase in serum phosphorus levels mediated by increased renal phosphate reabsorption. These data indicate that FGFR3 and 4 are the receptors that regulate serum 1,25(OH)2Vitamin D3 levels in response to FGF23. In addition, when 1,25(OH)2Vitamin D3 levels are not affected by FGF23, as in FGFR3-/-FGFR4-/- mice, a reduction in PTH can override the effects of FGF23 on renal phosphate transport.

Original languageEnglish (US)
Pages (from-to)F371-F377
JournalAmerican Journal of Physiology - Renal Physiology
Volume301
Issue number2
DOIs
StatePublished - Aug 2011

Keywords

  • FGF23
  • Phosphate
  • Proximal tubule

ASJC Scopus subject areas

  • Physiology
  • Urology

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