Bmi1过表达通过促进增殖、抑制凋亡纠正活性维生素D缺乏引起的骨量降低

Overexpression of Bmi1 Corrects Bone Loss Caused by Active Vitamin D Deficiency by Promoting Proliferation and Inhibiting Apoptosis

目的:探索B淋巴瘤Mo-MLV插入区1(B cell-specific MLV integration site-1,Bmi-1)过表达能否通过促进增殖、抑制凋亡改善1,25-二羟基维生素D(1,25-dihydroxy vitamin d,1,25(OH)_(2)D)缺乏引起的小鼠骨质骨量丢失。方法:取8月龄Bmi-1^(Tg)、Bmi1^(Tg)1α(OH)ase^(+/-)与1α(OH)ase^(+/-)小鼠以及同窝野生型(wild type,WT)小鼠椎骨组织,通过流式细胞术及TUNEL染色检测间充质干细胞周期变化及凋亡水平,通过PCNA染色及免疫组织化学染色检测小鼠椎骨组织中Bcl-2、Caspase-3等指标的变化,通过Western blot检测小鼠椎骨中Caspase-3、CDK4、CDK6、OPN、OCN等蛋白表达量的差异,通过ALP染色检查成骨细胞骨形成水平。结果:在骨髓间充质干细胞中过表达Bmi1可以通过促进增殖,抑制凋亡、增加成骨细胞骨形成来纠正1α(OH)ase^(+/-)小鼠的骨量降低。结论:Bmi1是1,25(OH)_(2)D的关键下游靶点,在防止1,25(OH)_(2)D缺乏引起的骨丢失方面起着至关重要的作用。

Objective:To investigate whether overexpression of B cell-specific MLV integration site-1(Bmi-1)can improve the phenotype of osteoporosis caused by 1,25(OH)_(2)D(1,25-dihydroxy vitamin d)deficiency in mice by promoting proliferation and inhibiting apoptosis.Methods:Vertebral tissues of 8-month-old Bmi-1^(Tg),Bmi1^(Tg)1α(OH)ase^(+/-)and 1α(OH)ase^(+/-)mice and homogenous Wild type(WT)mice were taken,and the cycle and apoptosis levels of mesenchymal stem cells were detected by flow cytometry and TUNEL staining.The changes of Bcl-2,Caspase-3 and other indexes in mouse vertebral tissues were detected by PCNA staining and immunohistochemical staining.Western blot was used to detect the protein expression levels of Caspase-3,CDK4,CDK6,OPN and OCN in mouse vertebrae,and ALP staining was used to check the level of osteoblast bone formation.Results:Overexpression of Bmi1 in bone marrow mesenchymal stem cells can correct the bone phenotype of 1α(OH)ase^(+/-)mice by promoting proliferation,inhibiting apoptosis and increasing osteoblast bone formation.Conclusion:Bmi1 is a key downstream target of 1,25(OH)_(2)D and plays a critical role in preventing bone loss caused by 1,25(OH)_(2)D deficiency.