Dataset Information
Elevation of extracellular Ca2+ induces store-operated calcium entry via calcium-sensing receptors: a pathway contributes to the proliferation of osteoblasts.
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ABSTRACT: Aims
The local concentration of extracellular Ca(2+) ([Ca(2+)]o) in bone microenvironment is accumulated during bone remodeling. In the present study we investigated whether elevating [Ca(2+)]o induced store-operated calcium entry (SOCE) in primary rat calvarial osteoblasts and further examined the contribution of elevating [Ca(2+)]o to osteoblastic proliferation.Methods
Cytosolic Ca(2+) concentration ([Ca(2+)]c) of primary cultured rat osteoblasts was detected by fluorescence imaging using calcium-sensitive probe fura-2/AM. Osteoblastic proliferation was estimated by cell counting, MTS assay and ATP assay. Agonists and antagonists of calcium-sensing receptors (CaSR) as well as inhibitors of phospholipase C (PLC), SOCE and voltage-gated calcium (Cav) channels were applied to study the mechanism in detail.Results
Our data showed that elevating [Ca(2+)]o evoked a sustained increase of [Ca(2+)]c in a dose-dependent manner. This [Ca(2+)]c increase was blocked by TMB-8 (Ca(2+) release inhibitor), 2-APB and BTP-2 (both SOCE blockers), respectively, whereas not affected by Cav channels blockers nifedipine and verapamil. Furthermore, NPS2143 (a CaSR antagonist) or U73122 (a PLC inhibitor) strongly reduced the [Ca(2+)]o-induced [Ca(2+)]c increase. The similar responses were observed when cells were stimulated with CaSR agonist spermine. These data indicated that elevating [Ca(2+)]o resulted in SOCE depending on the activation of CaSR and PLC in osteoblasts. In addition, high [Ca(2+)]o significantly promoted osteoblastic proliferation, which was notably reversed by BAPTA-AM (an intracellular calcium chelator), 2-APB, BTP-2, TMB-8, NPS2143 and U73122, respectively, but not affected by Cav channels antagonists.Conclusions
Elevating [Ca(2+)]o induced SOCE by triggering the activation of CaSR and PLC. This process was involved in osteoblastic proliferation induced by high level of extracellular Ca(2+) concentration.
SUBMITTER: Hu F
PROVIDER: S-EPMC4177836 | biostudies-literature | 2014
REPOSITORIES: biostudies-literature
Publications
Elevation of extracellular Ca2+ induces store-operated calcium entry via calcium-sensing receptors: a pathway contributes to the proliferation of osteoblasts.
PloS one 20140925 9
<h4>Aims</h4>The local concentration of extracellular Ca(2+) ([Ca(2+)]o) in bone microenvironment is accumulated during bone remodeling. In the present study we investigated whether elevating [Ca(2+)]o induced store-operated calcium entry (SOCE) in primary rat calvarial osteoblasts and further examined the contribution of elevating [Ca(2+)]o to osteoblastic proliferation.<h4>Methods</h4>Cytosolic Ca(2+) concentration ([Ca(2+)]c) of primary cultured rat osteoblasts was detected by fluorescence im ...[more]