Liu Di, Wang Yaoqing, Pan Zhenyu, Huang Zhen, Chen Fan
Department of Orthopedics, Zhongnan Hospital of Wuhan University, Wuhan, Hubei 430071, P.R. China.
Exp Ther Med. 2020 Sep;20(3):2166-2172. doi: 10.3892/etm.2020.8942. Epub 2020 Jun 25.
11β-hydroxysteroid dehydrogenase-2 (11β-HSD2) is one of the key enzymes in glucocorticoid metabolism, which can inactivate local corticosterone and regulate the level of active glucocorticoid in tissues. The expression of 11β-HSD2 and its regulatory pathway serve an important role in the apoptosis of steroid induced osteonecrosis of the femoral head (SANFH). The present study aimed to identify the regulatory effects of cAMP on the expression of Sp1 transcription factor (Sp1) and 11β-HSD2 in osteocytes at the cellular level. Murine long bone osteocyte Y4 (MLO-Y4) clone cells and mouse embryo osteoblast-like (MC3T3-E1) cells were cultured with adenylate cyclase activator or inhibitor (forskolin and SQ22536, respectively) to investigate the effects of alterations to intracellular cAMP levels. mRNA and protein expression levels of Sp1 and 11β-HSD2 were detected by reverse transcription-quantitative PCR and western blotting, respectively. Compared with the negative control group, the mRNA and protein expression levels of Sp1 were significantly increased in the activation group, whereas Sp1 expression levels were significantly decreased in the inhibition group. Similarly, compared with the negative control group, the mRNA and protein expression levels of 11β-HSD2 were significantly increased in the activator group, but significantly decreased in the inhibitor group. The aforementioned results indicated that intracellular cAMP levels significantly regulated the expression of Sp1 and 11β-HSD2 in mouse osteocytes and osteoblasts. Therefore, the present study suggested a potential therapeutic strategy for the prevention of osteonecrosis of the femoral head.
11β-羟类固醇脱氢酶-2（11β-HSD2）是糖皮质激素代谢的关键酶之一，可使局部皮质酮失活并调节组织中活性糖皮质激素的水平。11β-HSD2的表达及其调控途径在类固醇诱导的股骨头坏死（SANFH）的细胞凋亡中起重要作用。本研究旨在在细胞水平上确定环磷酸腺苷（cAMP）对骨细胞中Sp1转录因子（Sp1）和11β-HSD2表达的调控作用。用腺苷酸环化酶激活剂或抑制剂（分别为福斯可林和SQ22536）培养小鼠长骨骨细胞Y4（MLO-Y4）克隆细胞和小鼠胚胎成骨样（MC3T3-E1）细胞，以研究细胞内cAMP水平改变的影响。分别通过逆转录定量PCR和蛋白质印迹法检测Sp1和11β-HSD2的mRNA和蛋白质表达水平。与阴性对照组相比，激活组中Sp1的mRNA和蛋白质表达水平显著升高，而抑制组中Sp1的表达水平显著降低。同样，与阴性对照组相比，激活剂组中11β-HSD2的mRNA和蛋白质表达水平显著升高，但抑制剂组中显著降低。上述结果表明，细胞内cAMP水平显著调节小鼠骨细胞和成骨细胞中Sp1和11β-HSD2的表达。因此，本研究提出了一种预防股骨头坏死的潜在治疗策略。
