title: Mechanical Strain Regulates Osteoblast Proliferation Through Ca2+-CaMK-CREB Signal Pathway.
abstract: Objective To investigate the effects of mechanical strain on Ca2+-calmodulin dependent kinase (CaMK)-cAMP response element binding protein (CREB) signal pathway and proliferation of osteoblasts.Methods Using a four-point bending device, MC3T3-E1 cells were exposed to mechanical tensile strains of 2500 µs and 5000 µs at 0.5 Hz respectively. The intracellular free Ca2+([Ca2+]i) concentration and calmodulin activity were assayed by fluorospectrophotometry, CaMK II β, CREB, and phosphorylated (activated) CREB (p-CREB) were assessed by Western blot, and cells proliferation was assayed with MTT. Pretreatment with verapamil was carried out to block Ca2+channel, and inhibitor U73122 was used to inhibit phospholipase C (PLC).Results Mechanical strains of 2500 µs and 5000 µs for 1 to 10 minutes both increased [Ca2+]i level of the cells. The 2500 µs strain, a periodicity of 1 h/d for 3 days, activated calmodulin, elevated protein levels of CaMK II β and p-CREB, and promoted cells proliferation, which were attenuated by pretreatment of verapamil or U73122. The effects of 5000 µs strain on calmodulin, CaMK II β, p-CREB and proliferation were contrary to 2500 µs strain.Conclusion The mechanical strain regulates osteoblasts proliferation through Ca2+-CaMK-CREB signal pathway via Ca2+channel and PLC/IP3transduction cascades.
authors.affiliation: Depantment of Bioengineering, College of Biotechnology, Guilin Medical University, Guilin, Guangxi 541004, China; Institute of Medical Equipment, Academy of Military Medical Sciences, Tianjin 300161, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Experiment Management Center, Logistical College of People Armed Police Forces, Tianjin 300162, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Lv
authors.affiliation: Depantment of Bioengineering, College of Biotechnology, Guilin Medical University, Guilin, Guangxi 541004, China.
authors.forename: Xian-Qiong
authors.initials: XQ
authors.lastname: Zou
authors.affiliation: Depantment of Bioengineering, College of Biotechnology, Guilin Medical University, Guilin, Guangxi 541004, China.
authors.forename: Zhi-Xiong
authors.initials: ZX
authors.lastname: Yan
authors.affiliation: Depantment of Bioengineering, College of Biotechnology, Guilin Medical University, Guilin, Guangxi 541004, China; Experiment Management Center, Logistical College of People Armed Police Forces, Tianjin 300162, China.
authors.forename: Yu-Xian
authors.initials: YX
authors.lastname: Yan
mesh_terms: D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D049109:Cell Proliferation; D017362:Cyclic AMP Response Element-Binding Protein; D051379:Mice; D010006:Osteoblasts; D010766:Phosphorylation; D015398:Signal Transduction
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D017871:Calcium-Calmodulin-Dependent Protein Kinases