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Changes in the mRNA expression of osteoblast‐related genes in response to β 3 ‐adrenergic agonist in UMR106 cells
Author(s) -
Nuntapornsak Amporn,
Wongdee Kannikar,
Thongbunchoo Jirawan,
Krishnamra Nateetip,
Charoenphandhu Narattaphol
Publication year - 2010
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.1617
Subject(s) - osteoblast , endocrinology , agonist , medicine , chemistry , osteoprotegerin , osteocalcin , osteopontin , rankl , runx2 , receptor , bone resorption , activator (genetics) , adrenergic agonist , bone remodeling , alkaline phosphatase , biology , biochemistry , enzyme , in vitro
Activation of adrenergic receptors (AR) was demonstrated to result in either bone gain or bone loss depending on the activated AR subtypes and concentrations of agonists used. While β 2 ‐AR agonist was extensively investigated as an osteopenic agent, effects of β 3 ‐AR activation on osteoblasts were still elusive. Rat osteoblast‐like UMR106 cells were herein found to express several AR subtypes, including β 3 ‐AR. After exposure to a low‐dose β 3 ‐AR agonist BRL37344 (10 nmol L −1 ), UMR106 cells downregulated the mRNA expression of transcription factors Runx2 and Dlx5, which are important for initiation of osteoblast differentiation. Low‐dose BRL37344 also decreased the expression ratio of receptor activator of nuclear factor κ B ligand (RANKL) over osteoprotegerin (OPG), suggesting the protective effect of β 3 ‐AR agonist against bone resorption. Alkaline phosphatase expression was markedly decreased, whereas expressions of osteocalcin and osteopontin were increased by 100 nmol L −1 BRL37344, indicating that β 3 ‐AR activation could accelerate the transition of matrix maturation stage to mineralization stage. In conclusion, β 3 ‐AR activation in rat osteoblasts induced alteration in the expression of osteoblast‐related transcription factor genes as well as genes required for bone formation and resorption. The present results also suggest that, besides β 2 ‐AR, β 3 ‐AR is another AR subtype responsible for the sympathetic nervous system‐induced bone remodeling. Copyright © 2009 John Wiley & Sons, Ltd.