β雌激素受体介导脱氢表雄酮对OPG/RANKL的升调节

目的探讨β雌激素受体(ERβ)介导脱氢表雄酮(DHEA)对成骨细胞骨保护素/细胞核因子κB受体活化因子配体(OPG/RANKL)的调节作用。方法构建ERβ沉默表达(pLVTHM-GFP/ERβ-shRNA)和ERβ高表达(pWPT-ERβ)重组质粒,并转染人成骨细胞系hMG63,使hMG63的ERβ沉默表达(hMG63-shERβ)和高表达(hMG63-ERβ)。有或无U0126(丝裂原活化蛋白激酶信号途径中特异抑制分子)作用后,给予生理浓度(10-7mol.L-1)的DHEA作用24、48和72 h,ELISA和Western blot法分别检测hMG63培养上清中OPG和细胞中RANKL蛋白表达;Western blot法检测丝裂原活化蛋白激酶(MAPK)信号途径中pERK1/2、JNK和p38分子的表达。结果给予DHEA作用48和72 h后,hMG63分泌的OPG明显增高(P<0.01),而RANKL表达无明显变化;与hMG63细胞相比较,在DHEA作用下hMG63-shERβ和hMG63-ERβ组的ERα表达无明显改变;而hMG63-ERβ细胞中ERβ表达增高,伴随着pERK1/2和OPG的升高(P<0.05,P<0.01);相反,hMG63-shERβ组ERβ表达减少并伴随pERK1/2和OPG分泌的降低(P<0.05)。另外,DHEA对pERK1/2和OPG的升调节可部分被U0126阻断。结论 ERβ可能通过激活pERK1/2-MAPK途径介导了DHEA对成骨细胞OPG/RANKL的调节。

Regulation of dehydroepiandrosterone for OPG/RANKL in osteoblastic cell line via estrogen receptor beta subtype

Aim To investigate the regulation of dehydroepiandrosterone(DHEA) for osteoprotegrin(OPG) and receptor activator of nuclear factor kappa-B ligand(RANKL) via estrogen receptor beta(ERβ).Methods hMG63-ERβ group(infected with pWPT-ERβ),hMG63-shERβ group(infected with pLVTHM-GFP/ERβ-shRNA) and hMG63 group(control) were cultured and treated with 10-7 mol·L-1 DHEA,with or without U0126.The expression of OPG,RANKL,pERK1/2,JNK and p38 in hMG63 was evaluated by ELISA and Western blot,respectively.Results The expression of OPG increased by the time of DHEA culture(P<0.01),while there was no obvious change in RANKL expression.Compared with hMG63 cells,ERα in hMG63-shERβ and hMG63-ERβ group showed no significant change under the effect of DHEA.When the level of ERβ was high,DHEA could accelerate the expression of OPG and pERK1/2(P<0.05,P<0.01),which was blocked partly by U0126.In contrast,ERβ expression in hMG63-shERβ group was decreased in accordance with the decrease of pERK1/2 and OPG.Conclusion DHEA selectively acts on osteoblasts via the dominant receptor of ERβ,which mediates the pERK1/2-MAPK signal pathway for up-regulation of OPG instead of RANKL.