[Expression profiles of CaMKIIγ during osteoclast differentiation]

Abstract

To study the expression profiles and the role of Ca2+/calmodulin-dependent protein kinase IIγ (CaMKIIγ) during osteoclast differentiation. Methods: Mouse RAW264.7 cells were induced for osteoclastogenesis with 50 ng/mL receptor activator of nuclear factor-κB ligand (RANKL) and the cells were harvested at 0, 1, 3 and 5 days after induction. Tartrate-resistant acid phosphotase staining was performed to verify osteoclasts formation. RT-PCR, Western blot and immunofluorescent cytochemistry were used to detect the CaMKIIγ gene expression during osteoclastogenesis. Results: The osteoclasts were formed at day 3 under RANKL induction and more osteoclasts were observed at day 5. At day 0, 1, 3 and 5, the relative level of CaMKIIγ mRNA were (1.067±0.179), (1.840±0.070), (9.493±0.453) and (30.767±0.573), respectively, and the relative protein level were (0.454±0.065), (0.613±0.021), (0.858±0.019) and (0.980±0.023), respectively. CaMKIIγ expression was increased in a time-dependent manner except relative protein level at day 1 (P<0.01), which showed no significant difference at day 0 (P>0.05). Immunofluorescence assay showed that CaMKIIγ protein was also increased with differentiation of osteoclasts. Conclusion: The CaMKIIγ expression was increased in a time-depended manner during osteoclast differentiation and it might play a vital role during osteoclastogenesis.