Faculty Opinions recommendation of Leptin stimulates fibroblast growth factor 23 expression in bone and suppresses renal 1alpha,25-dihydroxyvitamin D3 synthesis in leptin-deficient mice.

2015 ◽  
Author(s):  
Mariano Rodriguez
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Fibroblast Growth Factor 23 ◽  
Fibroblast Growth ◽  
Dihydroxyvitamin D3 ◽  
Deficient Mice

scholarly journals Transgenic Mice Overexpressing Human Fibroblast Growth Factor 23 (R176Q) Delineate a Putative Role for Parathyroid Hormone in Renal Phosphate Wasting Disorders

Endocrinology ◽  
2004 ◽  
Vol 145 (11) ◽  
pp. 5269-5279 ◽  
Author(s):  
Xiuying Bai ◽  
Dengshun Miao ◽  
Jiarong Li ◽  
David Goltzman ◽  
Andrew C. Karaplis
Keyword(s):  
Vitamin D ◽  
Growth Factor ◽  
Transgenic Mice ◽  
Fibroblast Growth Factor ◽  
Calcium Homeostasis ◽  
Fibroblast Growth Factor 23 ◽  
Fibroblast Growth ◽  
Vitamin D Metabolism ◽  
Dihydroxyvitamin D3 ◽  
Circulating Levels

Abstract Fibroblast growth factor 23 (FGF23) is a recently characterized protein likely involved in the regulation of serum phosphate homeostasis. Increased circulating levels of FGF23 have been reported in patients with renal phosphate-wasting disorders, but it is unclear whether FGF23 is the direct mediator responsible for the decreased phosphate transport at the proximal renal tubules and the altered vitamin D metabolism associated with these states. To examine this question, we generated transgenic mice expressing and secreting from the liver human FGF23 (R176Q), a mutant form that fails to be degraded by furin proteases. At 1 and 2 months of age, mice carrying the transgene recapitulated the biochemical (decreased urinary phosphate reabsorption, hypophosphatemia, low serum 1,25-dihydroxyvitamin D3) and skeletal (rickets and osteomalacia) alterations associated with these disorders. Unexpectantly, marked changes in parameters of calcium homeostasis were also observed, consistent with secondary hyperparathyroidism. Moreover, in the kidney the anticipated alterations in the expression of hydroxylases associated with vitamin D metabolism were not observed despite the profound hypophosphatemia and increased circulating levels of PTH, both major physiological stimuli for 1,25-dihydroxyvitamin D3 production. Our findings strongly support the novel concept that high circulating levels of FGF23 are associated with profound disturbances in the regulation of phosphate and vitamin D metabolism as well as calcium homeostasis and that elevated PTH levels likely also contribute to the renal phosphate wasting associated with these disorders.

scholarly journals 1α,25-dihydroxyvitamin D3 acts predominately in mature osteoblasts under conditions of high extracellular phosphate to increase fibroblast growth factor 23 production in vitro

2010 ◽  
Vol 206 (3) ◽  
pp. 279-286 ◽  
Author(s):  
Ryoko Yamamoto ◽  
Tomoko Minamizaki ◽  
Yuji Yoshiko ◽  
Hirotaka Yoshioka ◽  
Kazuo Tanne ◽  
...  
Keyword(s):  
Growth Factor ◽  
Mrna Expression ◽  
Fibroblast Growth Factor ◽  
Fibroblast Growth Factor 23 ◽  
Prostaglandin E ◽  
Mrna Levels ◽  
Fibroblast Growth ◽  
Dihydroxyvitamin D3 ◽  
Osteoblast Development

Osteoblasts/osteocytes are the principle sources of fibroblast growth factor 23 (FGF23), a phosphaturic hormone, but the regulation of FGF23 expression during osteoblast development remains uncertain. Because 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) and inorganic phosphate (Pi) may act as potent activators of FGF23 expression, we estimated how these molecules regulate FGF23 expression during rat osteoblast development in vitro. 1,25(OH)2D3-dependent FGF23 production was restricted largely to mature cells in correlation with increased vitamin D receptor (VDR) mRNA levels, in particular, when Pi was present. Pi alone and more so in combination with 1,25(OH)2D3 increased FGF23 production and VDR mRNA expression. Parathyroid hormone, stanniocalcin 1, prostaglandin E2, FGF2, and foscarnet did not increase FGF23 mRNA expression. Thus, these results suggest that 1,25(OH)2D3 may exert its largest effect on FGF23 expression/production when exposed to high levels of extracellular Pi in osteoblasts/osteocytes.

scholarly journals A Control Region Near the Fibroblast Growth Factor 23 Gene Mediates Response to Phosphate, 1,25(OH)2D3, and LPS In Vivo

Endocrinology ◽  
2019 ◽  
Vol 160 (12) ◽  
pp. 2877-2891 ◽  
Author(s):  
Seong Min Lee ◽  
Alex H Carlson ◽  
Melda Onal ◽  
Nancy A Benkusky ◽  
Mark B Meyer ◽  
...  
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Fibroblast Growth Factor 23 ◽  
Mouse Strains ◽  
Fibroblast Growth ◽  
Vitamin D Metabolism ◽  
Dihydroxyvitamin D3 ◽  
Acute Injection ◽  
Insight Into

Abstract Fibroblast growth factor 23 (FGF23) is a bone-derived hormone involved in the control of phosphate (P) homeostasis and vitamin D metabolism. Despite advances, however, molecular details of this gene’s regulation remain uncertain. In this report, we created mouse strains in which four epigenetically marked FGF23 regulatory regions were individually deleted from the mouse genome using CRISPR/Cas9 gene-editing technology, and the consequences of these mutations were then assessed on Fgf23 expression and regulation in vivo. An initial analysis confirmed that bone expression of Fgf23 and circulating intact FGF23 (iFGF23) were strongly influenced by both chronic dietary P treatment and acute injection of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. However, further analysis revealed that bone Fgf23 expression and iFGF23 could be rapidly upregulated by dietary P within 3 and 6 hours, respectively; this acute upregulation was lost in the FGF23-PKO mouse containing an Fgf23 proximal enhancer deletion but not in the additional enhancer-deleted mice. Of note, prolonged dietary P treatment over several days led to normalization of FGF23 levels in the FGF23-PKO mouse, suggesting added complexity associated with P regulation of FGF23. Treatment with 1,25(OH)2D3 also revealed a similar loss of Fgf23 induction and blood iFGF23 levels in this mouse. Finally, normal lipopolysaccharide (LPS) induction of Fgf23 expression was also compromised in the FGF23-PKO mouse, a result that, together with our previous report, indicates that the action of LPS on Fgf23 expression is mediated by both proximal and distal Fgf23 enhancers. These in vivo data provide key functional insight into the genomic enhancers through which Fgf23 expression is mediated.

scholarly journals Ablation of the Galnt3 Gene Leads to Low-Circulating Intact Fibroblast Growth Factor 23 (Fgf23) Concentrations and Hyperphosphatemia Despite Increased Fgf23 Expression

Endocrinology ◽  
2009 ◽  
Vol 150 (6) ◽  
pp. 2543-2550 ◽  
Author(s):  
Shoji Ichikawa ◽  
Andrea H. Sorenson ◽  
Anthony M. Austin ◽  
Donald S. Mackenzie ◽  
Timothy A. Fritz ◽  
...  
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Fibroblast Growth Factor 23 ◽  
Proteolytic Processing ◽  
Tumoral Calcinosis ◽  
Uridine Diphosphate ◽  
Fibroblast Growth ◽  
Mineral Density ◽  
Deficient Mice

Familial tumoral calcinosis is characterized by ectopic calcifications and hyperphosphatemia. The disease is caused by inactivating mutations in fibroblast growth factor 23 (FGF23), Klotho (KL), and uridine diphosphate-N-acetyl-α-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase 3 (GALNT3). In vitro studies indicate that GALNT3 O-glycosylates a phosphaturic hormone, FGF23, and prevents its proteolytic processing, thereby allowing secretion of intact FGF23. In this study we generated mice lacking the Galnt3 gene, which developed hyperphosphatemia without apparent calcifications. In response to hyperphosphatemia, Galnt3-deficient mice had markedly increased Fgf23 expression in bone. However, compared with wild-type and heterozygous littermates, homozygous mice had only about half of circulating intact Fgf23 levels and higher levels of C-terminal Fgf23 fragments in bone. Galnt3-deficient mice also exhibited an inappropriately normal 1,25-dihydroxyvitamin D level and decreased alkaline phosphatase activity. Furthermore, renal expression of sodium-phosphate cotransporters and Kl were elevated in Galnt3-deficient mice. Interestingly, there were sex-specific phenotypes; only Galnt3-deficient males showed growth retardation, infertility, and significantly increased bone mineral density. In summary, ablation of Galnt3 impaired secretion of intact Fgf23, leading to decreased circulating Fgf23 and hyperphosphatemia, despite increased Fgf23 expression. Our findings indicate that Galnt3-deficient mice have a biochemical phenotype of tumoral calcinosis and provide in vivo evidence that Galnt3 plays an essential role in proper secretion of Fgf23 in mice.

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