Department of Orthopedics, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China.
Department of Orthopedics, Jinshan Hospital, Fudan University, Shanghai, China.
J Tissue Eng Regen Med. 2022 Dec;16(12):1184-1195. doi: 10.1002/term.3358. Epub 2022 Nov 8.
Blood vessel formation is the prerequisite for the survival and growth of tissue-engineered bone. Mineralized osteoblasts (MOBs) have been shown to regulate angiogenesis through the secretion of exosomes containing various pro-angiogenic factors. However, whether the mineralized osteoblast-derived exosomes (MOB-Exos) containing let-7f-5p can regulate the angiogenesis of endothelial cells (ECs) is still unknown. In this study, the angiogenic capabilities of ECs respectively treated with MOB-Exos, let-7f-5p mimicked MOB-Exos (miR mimic group), and let-7f-5p inhibited MOB-Exos (miR inhibitor group) were compared through in vitro and in vivo studies. Moreover, the potential mechanism of MOB-Exo let-7f-5p regulating angiogenesis was explored by verifying the role of the Erk1/2 signaling pathway and target gene DUSP1. The results showed that MOB-Exos could significantly promote the angiogenesis of ECs, which could be enhanced by mimicked exosomal let-7f-5p and attenuated by inhibited exosomal let-7f-5p. Let-7f-5p could suppress the luciferase activity of wide-type DUSP1, and the mutation of DUSP1 could abrogate the repressive ability of let-7f-5p. Furthermore, the expression of DUSP1 exhibited a reversed trend to that of pErk1/2. The expression of pErk1/2 was significantly higher in the miR mimic group and lower in the miR inhibitor group than that in the MOB-Exos group, while inhibition of pErk1/2 could partly impair the angiogenic capabilities of ECs. In conclusion, we concluded that exosomal let-7f-5p derived from MOBs could promote the angiogenesis of ECs via activating the DUSP1/Erk1/2 signaling pathway, which might be a promising target for promoting the angiogenesis of tissue-engineered bone.
血管生成是组织工程骨存活和生长的前提。矿化成骨细胞（MOBs）通过分泌含有各种促血管生成因子的外泌体来调节血管生成已得到证实。然而，含有 let-7f-5p 的矿化成骨细胞衍生的外泌体（MOB-Exos）是否可以调节内皮细胞（ECs）的血管生成尚不清楚。在这项研究中，通过体外和体内研究比较了分别用 MOB-Exos、let-7f-5p 模拟 MOB-Exos（miR 模拟组）和 let-7f-5p 抑制 MOB-Exos（miR 抑制组）处理的 ECs 的血管生成能力。此外，通过验证 Erk1/2 信号通路和靶基因 DUSP1 的作用，探讨了 MOB-Exo let-7f-5p 调节血管生成的潜在机制。结果表明，MOB-Exos 可显著促进 ECs 的血管生成，而外泌体 let-7f-5p 的模拟可增强其作用，外泌体 let-7f-5p 的抑制则可减弱其作用。let-7f-5p 可抑制野生型 DUSP1 的荧光素酶活性，而 DUSP1 的突变可消除 let-7f-5p 的抑制能力。此外，DUSP1 的表达与 pErk1/2 的表达呈相反趋势。miR 模拟组中 pErk1/2 的表达明显高于 MOB-Exos 组，miR 抑制组中 pErk1/2 的表达明显低于 MOB-Exos 组，而抑制 pErk1/2 可部分损害 ECs 的血管生成能力。综上所述，我们得出结论，MOB 衍生的外泌体 let-7f-5p 可通过激活 DUSP1/Erk1/2 信号通路促进 ECs 的血管生成，这可能是促进组织工程骨血管生成的有前途的靶点。
