Soluble Klotho causes hypomineralization in Klotho-deficient mice
JEndocrinol_237_285.pdf 1.52 MB
Aubin, Jane E.
The type I transmembrane protein αKlotho (Klotho) serves as a coreceptor for the phosphaturic hormone fibroblast growth factor 23 (FGF23) in kidney, while a truncated form of Klotho (soluble Klotho, sKL) is thought to exhibit multiple activities, including acting as a hormone, but whose mode(s) of action in different organ systems remains to be fully elucidated. FGF23 is expressed primarily in osteoblasts/osteocytes and aberrantly high levels in the circulation acting via signaling through an FGF receptor (FGFR)-Klotho coreceptor complex cause renal phosphate wasting and osteomalacia. We assessed the effects of exogenously added sKL on osteoblasts and bone using Klotho-deficient (kl/kl) mice and cell and organ cultures. sKL induced FGF23 signaling in bone and exacerbated the hypomineralization without exacerbating the hyperphosphatemia, hypercalcemia and hypervitaminosis D in kl/kl mice. The same effects were seen in rodent bone models in vitro, in which we also detected formation of a sKL complex with FGF23-FGFR and decreased Phex (gene responsible for X-linked hypophosphatemic rickets (XLH)/osteomalacia) expression. Further, sKL-FGF23-dependent hypomineralization in vitro was rescued by soluble PHEX. These data suggest that exogenously added sKL directly participates in FGF23 signaling in bone and that PHEX is a downstream effector of the sKL-FGF23-FGFR axis in bone.
This work was supported in part by grants from the Ministry of Education, Science, Sports and Culture, Japan (18592001 and 20592139 to Y Y and 21791788 to T M), and the Canadian Institutes of Health Research (MOP 83704 to J E A).
Journal of Endocrinology
|date of issued||
Society for Endocrinology
This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Endocrinology, copyright © Society for Endocrinology after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1530/JOE-17-0683. This is not the published version. Please cite only the published version. この論文は出版社版でありません。引用の際には出版社版をご確認、ご利用ください。
Graduate School of Biomedical & Health Sciences
University Medical Hospital
Post-print version/PDF may be used in an institutional repository after an embargo period of 12 months.