Zhao Haibo, Chen Wei, Chen Jinli, Qi Chao, Wang Tianrui, Zhang Jing, Qu Di, Yu Tengbo, Zhang Yingze
Department of Orthopedics, Affiliated Hospital of Qingdao University, Qingdao, China.
Third Affiliated Hospital of Hebei Medical University, Shi Jiazhuang, China.
Front Chem. 2022 Jul 4;10:908312. doi: 10.3389/fchem.2022.908312. eCollection 2022.
Tendons are the special connective tissue that connects bones to muscles and governs joint movement in response to loads passed by muscles. The healing of tendon injuries is still a challenge. In recent years, adipose-derived mesenchymal stem cells (ADSCs) have been increasingly used for tissue regeneration, but the underlying mechanism of tendon injury still remains unclear. High-throughput sequencing was used to identify a novel lncRNA, whose expression was significantly decreased in injured tendon compared with normal tendon. Furthermore, pyrosequencing, nuclear-cytoplasmic separation, FISH assay and qRT-PCR analysis were used to verify the level of lncRNA methylation in the injured tenocytes. lncRNA was confirmed to promote the proliferation of tenocytes by flow cytometry, wound healing assay, qRT-PCR, and western blot, and the target gene of lncRNA was predicted and verified. To confirm that ADSCs could repair injured tendons, ADSCs and injured tenocytes were co-cultured , and ADSCs were injected into injured tendons , respectively. The lncRNA Morf4l1 promoter methylation in injured tendons led to down-regulation of its expression and inhibition of tenocyte proliferation. LncRNA Morf4l1 promoted the expression of TGF-β2 by targeting 3'U of miR-145-5p. After co-cultured ADSCs and injured tenocytes, the expression of lncRNA Morf4l1 was up-regulated, and the proliferation of injured tenocytes was promoted. The ADSCs were injected into the injured tendon to repair the injured tendon . This study confirmed that ADSCs promoted tendon wound healing by reducing the methylation level of lncRNA Morf4l1.
肌腱是一种特殊的结缔组织，它将骨骼与肌肉相连，并在肌肉传递负荷时控制关节运动。肌腱损伤的愈合仍然是一个挑战。近年来，脂肪来源的间充质干细胞（ADSCs）越来越多地用于组织再生，但肌腱损伤的潜在机制仍不清楚。利用高通量测序鉴定了一种新的lncRNA，与正常肌腱相比，其在损伤肌腱中的表达显著降低。此外，采用焦磷酸测序、核质分离、FISH检测和qRT-PCR分析来验证损伤肌腱细胞中lncRNA的甲基化水平。通过流式细胞术、伤口愈合试验、qRT-PCR和蛋白质印迹法证实lncRNA促进肌腱细胞增殖，并对lncRNA的靶基因进行了预测和验证。为了证实ADSCs可以修复损伤的肌腱，分别将ADSCs与损伤的肌腱细胞共培养，并将ADSCs注射到损伤的肌腱中。损伤肌腱中lncRNA Morf4l1启动子甲基化导致其表达下调并抑制肌腱细胞增殖。LncRNA Morf4l1通过靶向miR-145-5p的3'UTR促进TGF-β2的表达。ADSCs与损伤的肌腱细胞共培养后，lncRNA Morf4l1的表达上调，损伤的肌腱细胞增殖得到促进。将ADSCs注射到损伤的肌腱中以修复损伤的肌腱。本研究证实ADSCs通过降低lncRNA Morf4l1的甲基化水平促进肌腱伤口愈合。
