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Mouse Osteoblastic Cell Line (MC3T3‐E1) Expresses Extracellular Calcium (Ca 2+ o )–Sensing Receptor and Its Agonists Stimulate Chemotaxis and Proliferation of MC3T3‐E1 Cells
Author(s) -
Yamaguchi Toru,
Chattopadhyay Naibedya,
Kifor Olga,
Butters Robert R.,
Sugimoto Toshitsugu,
Brown Edward M.
Publication year - 1998
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1359/jbmr.1998.13.10.1530
Subject(s) - bone resorption , extracellular , microbiology and biotechnology , chemistry , parathyroid hormone , osteoblast , bone remodeling , receptor , medicine , calcium , cell culture , endocrinology , biology , biochemistry , genetics , organic chemistry , in vitro
The calcium‐sensing receptor (CaR) is a G protein‐coupled receptor that plays key roles in extracellular calcium ion (Ca 2+ o ) homeostasis in parathyroid gland and kidney. Osteoblasts appear at sites of osteoclastic bone resorption during bone remodeling in the “reversal” phase following osteoclastic resorption and preceding bone formation. Bone resorption produces substantial local increases in Ca 2+ o that could provide a signal for osteoblasts in the vicinity, leading us to determine whether such osteoblasts express the CaR. In this study, we used the mouse osteoblastic, clonal cell line MC3T3‐E1. Both immunocytochemistry and Western blot analysis, using an antiserum specific for the CaR, detected CaR protein in MC3T3‐E1 cells. We also identified CaR transcripts in MC3T3‐E1 cells by Northern analysis using a CaR‐specific riboprobe and by reverse transcription‐polymerase chain reaction with CaR‐specific primers, followed by nucleotide sequencing of the amplified products. Exposure of MC3T3‐E1 cells to high Ca 2+ o (up to 4.8 mM) or the polycationic CaR agonists, neomycin and gadolinium (Gd 3+ ), stimulated both chemotaxis and DNA synthesis in MC3T3‐E1 cells. Therefore, taken together, our data strongly suggest that the osteoblastic cell line MC3T3‐E1 possesses both CaR protein and mRNA very similar, if not identical, to those in parathyroid and kidney. Furthermore, the CaR in these osteoblasts could play a key role in regulating bone turnover by stimulating the proliferation and migration of such cells to sites of bone resorption as a result of local release of Ca 2+ o .