Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001, Fujian, China.
Department of Internal Medicine, Fujian Provincial Hospital South Branch, Fuzhou, 350001, Fujian, China.
J Bone Miner Metab. 2021 Jul;39(4):572-582. doi: 10.1007/s00774-021-01212-7. Epub 2021 Apr 5.
PTH1-34 can stimulate osteoblast formation, which contributes to the improvement of bone loss. PTH1-34 can activate autophagy, and autophagy plays a key role in osteoblast formation. This study aimed to explore the role of autophagy in PTH1-34-regulated osteoblastogenesis.
In this study, the mice treated with ovariectomy (OVX mice) were used to observe the effect of PTH1-34 on the formation and autophagy of osteoblasts in trabecular bone in vivo. Osteoblast precursor cell line MC3T3-E1 was treated with PTH1-34, and then the autophagic parameters of osteoblast precursors (including autophagic proteins and autophagosome formation) were detected using Western Blotting and Transmission Electron Microscopy. Next, after using autophagic pharmacological inhibitor (3-MA) and silencing vectors of autophagic molecule Beclin1 to downregulate autophagic activity, the parameters related to osteogenesis (including ALP staining intensity, ALP activity, cell proliferation and osteoblastic protein expression) were evaluated using corresponding assays.
In vivo results showed that PTH1-34 not only improved bone loss caused by OVX but also restored Beclin1 expression and autophagic activity of immature osteoblasts in bone tissues. In vitro assays also showed that treatment of PTH1-34 enhanced the autophagy in osteoblast precursors. Moreover, under PTH1-34 intervention, the upregulated osteogenic parameters were reversed by autophagic inhibition with 3-MA. Of note, Beclin1 silencing can recover the osteogenic activity enhanced by PTH1-34.
PTH1-34 can enhance the autophagic activity of osteoblast precursors, which is involved in PTH1-34-regulated osteoblast formation. Furthermore, Beclin1, as a key autophagic regulator, plays a pivotal role in PTH1-34-regulated osteoblast precursor autophagy and osteoblastogenesis.
PTH1-34 可刺激成骨细胞形成，从而改善骨质流失。PTH1-34 可激活自噬，而自噬在成骨细胞形成中起着关键作用。本研究旨在探讨自噬在 PTH1-34 调节成骨细胞形成中的作用。
本研究中，使用去卵巢（OVX 小鼠）处理的小鼠来观察 PTH1-34 对骨小梁中成骨细胞形成和自噬的体内影响。用 PTH1-34 处理成骨前体细胞系 MC3T3-E1，然后用 Western Blotting 和透射电子显微镜检测成骨前体细胞的自噬参数（包括自噬蛋白和自噬体形成）。接下来，使用自噬药理学抑制剂（3-MA）和自噬分子 Beclin1 的沉默载体下调自噬活性后，使用相应的测定法评估与成骨相关的参数（包括 ALP 染色强度、ALP 活性、细胞增殖和成骨蛋白表达）。
体内结果表明，PTH1-34 不仅改善了 OVX 引起的骨质流失，而且恢复了骨组织中成骨细胞不成熟时的 Beclin1 表达和自噬活性。体外实验还表明，PTH1-34 处理增强了成骨前体细胞的自噬作用。此外，在 PTH1-34 干预下，自噬抑制 3-MA 逆转了上调的成骨参数。值得注意的是，Beclin1 沉默可以恢复 PTH1-34 增强的成骨活性。
PTH1-34 可以增强成骨前体细胞的自噬活性，这涉及到 PTH1-34 调节成骨细胞形成。此外，作为关键自噬调节剂的 Beclin1 在 PTH1-34 调节成骨前体细胞自噬和成骨细胞形成中起着关键作用。
