重组人结缔组织生长因子对人成骨细胞骨保护素/RANKL表达的影响

Effects of recombinant human connective tissue growth factor on the expression of osteoprotegerin and receptor activator of NF-κB ligand in human osteoblasts

目的 研究重组人结缔组织生长因子（CTGF）对体外培养的人成骨细胞骨保护素/RANKL（receptor activator of NF-κB ligand）表达的影响,并探讨重组人CTGF调节骨保护素/RANKL表达的信号转导机制.方法 用重组人CTGF干预体外培养的人成骨细胞,采用Western印迹法检测骨保护素/RANKL蛋白表达水平的变化,同时观察重组人CTGF对人成骨细胞FAK、MAPK磷酸化的影响.结果 重组人CTGF可呈时间-剂量依赖性抑制人成骨细胞RANKL的表达,200 ng/ml重组人CTGF作用24～48 h达最大抑制效果,而对人成骨细胞骨保护素的表达无明显影响.重组人CTGF可明显增强p38MAPK磷酸化,并减少FAK磷酸化,重组人CTGF干预对ERK、JNK磷酸化无明显影响;p38MAPK阻断剂SB23058可阻断重组人CTGF对RANKL表达的抑制效应.结论 重组人CTGF通过增强p38MAPK磷酸化,减少FAK磷酸化下调人成骨细胞RANKL的表达.

Objective To investigate the effects of recombinant human connective tissue growth factor （rCTGF） on the expression of osteoprotegerin （OPG） and RANKL （ receptor activator of NF-κB ligand ） in human osteoblasts, as well as the mechanisms involved. Methods Human osteoblasts were treated with rCTGF. The expressions of OPG and RANKL were assessed by Western blotting. The expressions of focal adhesion kinase （ FAK）, mitogen-activated protein kinase （MAPK） were also observed. Results rCTGF inhibited RANKL protein expression in a dose-and time-depentent manner in human osteoblasts, while the expression of OPG kept unchanged. rCTGF induced activation of p38MAPK and dephosphorylation of FAK in human osteoblasts, but had no effect on ERK and JNK phosphorylation. p38MAPK inhibitor SB23058 abrogated the inhibitory effect of rCTGF on RANKL in human osteoblasts. Conclusion rCTGF inhibits the expression of RANKL in human osteoblasts via activation of p38MAPK and dephosphorylation of FAK.