Osteopontin Gene Regulation by Oscillatory Fluid Flow via Intracellular Calcium Mobilization and Activation of Mitogen-activated Protein Kinase in MC3T3–E1 Osteoblasts

摘要: Recently fluid flow has been shown to be a potent physical stimulus in the regulation of bone cell metabolism. However, most investigators have applied steady or pulsing profiles rather than oscillatory flow, which occurs vivo because mechanical loading. Here was demonstrated potentially important signal for loading-induced changes We selected three well known biological response variables including intracellular calcium (Ca2+i), mitogen-activated protein kinase (MAPK) activity, and osteopontin (OPN) mRNA levels examine MC3T3–E1 osteoblastic cells with shear stresses ranging from 2 −2 Newtons/m2 at 1 Hz, is range expected occur during routine activities. Our results showed that within min, induced Ca2+i mobilization, whereas two MAPKs (ERK p38) were activated over 2-h time frame. there no activation JNK. Furthermore h increased steady-state OPN expression by approximately 4-fold, 24 after exposure flow. The presence both ERK p38 inhibitors thapsigargin completely abolished effect on levels. In addition, experiments using variety pharmacological agents suggest induces mobilization via L-type voltage-operated channel inositol 1,4,5-trisphosphate pathway.