title: Effects of HA released calcium ion on osteoblast differentiation.
abstract: Hydroxyapatite (HA) is a widely used calcium phosphate implant substitute and has dissolution property. Although HA has been shown a beneficial effect on osteoblast differentiation, the exact mechanism is still unclear. In the present study, we proposed that Ca(2+) released from HA activated the expression bone associated proteins, OPN and BSP, mediated by L-type calcium channel and calcium/calmodulin-dependent protein kinase (CaMK) 2 which resulted into improved osteoblast differentiation. Results showed that HA elevated ALP expression as well as OPN and BSP expression in MC3T3-E1 cells. The result from western blot of CaMK2alpha indicated that HA released Ca(2+) activated CaMK2 through L-type calcium channel. Furthermore, upregulation of OPN and BSP mRNA expression was significantly inhibited when blocking both the L-type calcium channel and CaMK2. These findings suggested that HA accelerated the osteoblast differentiation by releasing Ca(2+).
authors.affiliation: Interdisciplinary Program for Bioengineering, Seoul National University, Seoul, 152-742, Korea.
authors.forename: Gil-Yong
authors.initials: GY
authors.lastname: Jung
authors.forename: Yoon-Jeong
authors.initials: YJ
authors.lastname: Park
authors.forename: Jung-Suk
authors.initials: JS
authors.lastname: Han
mesh_terms: D000818:Animals; D056735:Autoimmune Lymphoproliferative Syndrome; D001842:Bone and Bones / Q000378:metabolism; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D020746:Calcium Channels, L-Type / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D002128:Calcium Metabolism Disorders / Q000235:genetics / Q000378:metabolism; D002130:Calcium Phosphates / Q000378:metabolism / Q000494:pharmacology; D002136:Calcium, Dietary / Q000378:metabolism / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects* / Q000235:genetics; D002999:Clone Cells; D017886:Durapatite / Q000378:metabolism / Q000494:pharmacology; D058574:Integrin-Binding Sialoprotein; D007477:Ions / Q000378:metabolism / Q000494:pharmacology; D051379:Mice; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010012:Osteogenesis / Q000235:genetics; D012795:Sialoglycoproteins; D015854:Up-Regulation
chemical_list: D020746:Calcium Channels, L-Type; D002130:Calcium Phosphates; D002136:Calcium, Dietary; C546872:Ibsp protein, mouse; D058574:Integrin-Binding Sialoprotein; D007477:Ions; D012795:Sialoglycoproteins; D017886:Durapatite; C020243:calcium phosphate; D002118:Calcium