Osteoblasts regulate bone formation and remodeling, and are main target cells of oxidative stress in the
progression of osteonecrosis. The stem cell factor (SCF)-c-Kit pathway plays important roles in the
proliferation, differentiation and survival in a range of cell types, but little is known about its functions
in osteoblasts. In this study, we found that c-Kit is functionally expressed in both osteoblastic-like
MC3T3-E1 cells and primary murine osteoblasts. Its ligand SCF exerted significant cyto-protective effects
against hydrogen peroxide (H2O2). SCF activated its receptor c-Kit in osteoblasts, which was required for
its cyto-protective effects against H2O2. Pharmacological inhibition (by Imatinib and Dasatinib) or
shRNA-mediated knockdown of c-Kit thus inhibited SCF-mediated osteoblast protection. Further investigations
showed that protection by SCF against H2O2 was mediated via activation of c-Kit-dependent
Akt pathway. Inhibition of Akt activation, through pharmacological or genetic means, suppressed
SCF-mediated anti-H2O2 activity in osteoblasts. In summary, we have identified a new SCF-c-Kit-Akt
physiologic pathway that protects osteoblasts from H2O2-induced damages, and might minimize the risk
of osteonecrosis caused by oxidative stress.
Osteoblasts regulate bone formation and remodeling, and are main target cells of oxidative stress in the
progression of osteonecrosis. The stem cell factor (SCF)-c-Kit pathway plays important roles in the
proliferation, differentiation and survival in a range of cell types, but little is known about its functions
in osteoblasts. In this study, we found that c-Kit is functionally expressed in both osteoblastic-like
MC3T3-E1 cells and primary murine osteoblasts. Its ligand SCF exerted significant cyto-protective effects
against hydrogen peroxide (H2O2). SCF activated its receptor c-Kit in osteoblasts, which was required for
its cyto-protective effects against H2O2. Pharmacological inhibition (by Imatinib and Dasatinib) or
shRNA-mediated knockdown of c-Kit thus inhibited SCF-mediated osteoblast protection. Further investigations
showed that protection by SCF against H2O2 was mediated via activation of c-Kit-dependent
Akt pathway. Inhibition of Akt activation, through pharmacological or genetic means, suppressed
SCF-mediated anti-H2O2 activity in osteoblasts. In summary, we have identified a new SCF-c-Kit-Akt
physiologic pathway that protects osteoblasts from H2O2-induced damages, and might minimize the risk
of osteonecrosis caused by oxidative stress.
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