靶向激活AMPK信号通路抗激素诱导的成骨细胞损伤作用及机制研究

Excessive glucocorticoid (GC) usage may lead to non-traumatic femoral head osteonecrosis. Dexamethasone (Dex) is shown to exert cytotoxic effect s directly to osteoblasts. Our previous studies have shown that Compound 13 (C13), a novelα1 selective AMP-activated protein kinase (AMPK) activator, alleviates Dex-induced osteoblast cell apoptosis via activating AMPK signaling. Our preliminary results showed that the AMPK inhibitory miRNA, or microRNA-451 (miRNA-451), was upregulated in patients’ osteonecrosis femoral head tissues, which was accompanied with AMPK signaling inhibition. In the current proposal, by using multiple bio-medical assays, we will first test the AMPK signaling and miRNA-451 expression in normal and GC-caused osteonecrosis femoral head tissues. We are set to study the osteoblast cytoprotection against Dex by the newly-indentified AMPK activators, C13 and antagomiR-451, in vitro and in vivo. The underlying signaling mechanisms will also be explored. This study suggests that forced-activation of AMPK in osteoblasts may offer significant cyto-protection against Dex-induced damages. Meanwhile, the novel AMPK activators (C13 and antagomiR-451) might be further studied in clinical settings for the treatment of steroid-induced femoral head necrosis.

糖皮质激素诱导成骨细胞凋亡致股骨头坏死。我们前期研究发现，添加α1选择性AMPK激动剂Compound 13（C13）显著抑制地塞米松诱导成骨细胞凋亡。预实验结果显示，在多个人激素性股骨头坏死组织中，AMPK抑制性miRNA-451表达显著增加，并伴随着AMPK活性显著下降。而在成骨细胞株中转染反义miRNA-451（antagomiR-451）则导致AMPK持续活化，显著拮抗地塞米松损伤。本项目中，拟系统检测激素性股骨头坏死组织中AMPK信号通路及miRNA-451表达水平，并分析他们与股骨头坏死各临床指标的相关性；拟运用细胞和小鼠激素性股骨头坏死模型，明确C13及反义miRNA-451激活AMPK信号通路而拮抗激素性成骨细胞损伤作用，阐明相关的分子信号机制。旨在论证通过激活成骨细胞AMPK通路拮抗地塞米松损伤的理论，为运用AMPK激动剂治疗激素性股骨头坏死提供实验基础。

前期研究发现添加α1选择性AMPK激动剂Compound 13（C13）显著抑制地塞米松诱导成骨细胞凋亡。研究结果显示，在人激素性股骨头坏死组织和小鼠激素性股骨头模型组织中，AMPK抑制性miRNA-451表达显著增加，并伴随着AMPK活性显著下降；而在成骨细胞株中转染反义miRNA-451（antagomiR-451）导致AMPK持续活化，显著拮抗地塞米松损伤。该项目系统检测了激素性股骨头坏死组织中AMPK信号通路及miRNA-451表达水平；运用细胞和小鼠激素性股骨头坏死模型，明确了C13及反义miRNA-451激活AMPK信号通路而拮抗激素性成骨细胞损伤作用，并阐明了相关的分子信号机制。该项目论证了通过激活成骨细胞AMPK通路拮抗地塞米松损伤的理论。