Where phosphate meets FGF23: The impact of phosphate types on the FGF23 regulatory landscape

This research explores the regulation of fibroblast growth factor 23 (FGF23), a hormone essential for controlling phosphate levels in the body. Phosphate, needed for many cell activities, is absorbed from food in both organic and inorganic forms. The study found that only organic phosphate increases FGF23 levels in cell experiments. Key cellular pathways help control this increase, particularly the mitogen-activated protein kinase (MAPK) and transforming growth factor beta (TGF-β) pathways. Blocking MAPK lowered FGF23, while blocking TGF-β raised it, indicating a balance between these two. Additionally, the study shows that vitamin D, specifically in its 25-hydroxy form, boosts FGF23 levels, especially when combined with phosphate. This process likely involves specific cell receptors. Another finding was that a pathway called sirtuin 1-hairy and enhancer of split 1 (SIRT1-HES1) plays a central role in FGF23 activation by organic phosphate. These insights may help develop new treatments for conditions related to phosphate balance.