Inhibition of mechanical stress-induced NF-κB promotes bone formation.
OBJECTIVE
Nuclear factor kappaB (NF-κB) plays an important role in osteogenesis. This study was performed to investigate the effects of mechanical force on NF-κB activity in osteoblast-like cells.


METHODS
U2OS cells were harvested at specific time points after mechanical loading. U2OS nuclear extracts were prepared for Western blot assay and electrophoretic mobility shift assay electrophoretic mobility shift assay (EMSA). Total RNA was isolated using TRIzol for real-time PCR.


RESULTS
P-p65 (Ser536) expression in the nucleus was significantly higher after loading force on U2OS cells. The amount of nuclear NF-κB also increased. Ammonium pyrrolidinedithiocarbamate(PDCT) inhibited compressive force-induced NF-κB activity in EMSA. Further, PDTC attenuated the transcriptional inhibition of alkaline phosphatase (ALP), RUNX-2 and Osteocalcin by down-regulating NF-κB activity.


CONCLUSIONS
Mechanical force enhances NF-κB activity in osteoblast-like cells, and compressive force affects the downstream bone marker genes through NF-κB.
Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, China.
S
S
Zhou
J
J
Zhang
H
H
Zheng
Y
Y
Zhou
F
F
Chen
J
J
Lin
D000469:Alkaline Phosphatase / Q000032:analysis; D000880:Anthraquinones; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000648:ultrastructure; D049109:Cell Proliferation; D004396:Coloring Agents; D050659:Core Binding Factor Alpha 1 Subunit / Q000032:analysis; D024202:Electrophoretic Mobility Shift Assay; D006801:Humans; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000502:physiology*; D010006:Osteoblasts / Q000166:cytology / Q000502:physiology*; D015675:Osteocalcin / Q000032:analysis; D010012:Osteogenesis / Q000502:physiology*; D011759:Pyrrolidines / Q000494:pharmacology; D012313:RNA / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction; D013314:Stress, Mechanical; D013859:Thiocarbamates / Q000494:pharmacology; D051996:Transcription Factor RelA / Q000032:analysis
D000880:Anthraquinones; D004396:Coloring Agents; D050659:Core Binding Factor Alpha 1 Subunit; D016328:NF-kappa B; D011759:Pyrrolidines; C493709:RUNX2 protein, human; D013859:Thiocarbamates; D051996:Transcription Factor RelA; D015675:Osteocalcin; C020972:pyrrolidine dithiocarbamic acid; C004468:Alizarin Red S; D012313:RNA; D000469:Alkaline Phosphatase