The production of fibroblast growth factor 23 is controlled by TGFß2

Transforming growth factor-ss (TGF-ss) is a cytokine produced by many cell types and implicated in cell growth, differentiation, apoptosis, and inflammation. It stimulates store-operated calcium entry (SOCE) through the calcium release-activated calcium (CRAC) channel Orai1/ Stim1 in endometrial Ishikawa cells. Bone cells generate fibroblast growth factor (FGF) 23, which inhibits renal phosphate reabsorption and 1,25(OH)(2)D-3 formation in concert with its co-receptor Klotho. Moreover, Klotho and FGF23 counteract aging and age-related clinical conditions. FGF23 production is dependent on Orai1mediated SOCE and inflammation. Here, we explored a putative role of TGF-ss 2 in FGF23 synthesis. To this end, UMR106 osteoblast-like cells were cultured, Fgf23 transcript levels determined by qRT-PCR, FGF23 protein measured by ELISA, and SOCE analyzed by fluorescence optics. UMR106 cells expressed TGF-ss receptors 1 and 2. TGF-ss 2 enhanced SOCE and potently stimulated the production of FGF23, an effect significantly attenuated by SB431542, an inhibitor of the transforming growth factor-ss(TGF-ss) type I receptor activin receptor-like kinases ALK5, ALK4, and ALK7. Furthermore, the TGF-ss 2 effect on FGF23 production was blunted by SOCE inhibitor 2-APB. We conclude that TGF-ss 2 induces FGF23 production, an effect involving up-regulation of SOCE.