Department of Orthopedic, Xijing Hospital, Fourth Military Medical University, Western Changle Road, Xi'an, Shaanxi Province, PR China.
Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Western Changle Road, Xi'an, Shaanxi Province, PR China; Department of Pharmacy, The 456th Hospital of the People's Liberation Army, Jinan, PR China.
Life Sci. 2021 Jan 15;265:118778. doi: 10.1016/j.lfs.2020.118778. Epub 2020 Nov 18.
The intervertebral disc is the largest avascular organ of the body. Vascularization of the disc has been typically regarded as a pathological feature of intervertebral disc degeneration (IDD). However, the underlying mechanism of vascularization in IDD is still unclear. The current study aimed to investigate the role of AF cell derived exosome (AF-exo) in the interaction with human umbilical vein endothelial cells (HUVECs) and its potential role in the regulation of vascularization in IDD.
Human AF tissues were obtained from patients with IDD and idiopathic scoliosis. The AF-exo were isolated and identified by transmission electron microscopy (TEM), nanoparticle trafficking analysis (NTA) and Western blotting. Then, the AF-exo were used for HUVECs cultures. The migration of HUVECs was observed in 2D and 3D cultures. The inflammatory phenotype of HUVECs was examined by Real-time PCR and enzyme-linked immunosorbent assay (ELISA). Additionally, apoptosis of HUVECs were analyzed by flow cytometry.
Here, we for the first time found that AF cells could secrete AF-exo and that the AF-exo could be phagocytosed by HUVECs. Additionally, we found that degenerated AF-exo exerted pro-vascularization effect on HUVECs by promoting cell migration (in 2D and 3D cultures) and inflammatory factor expression including IL-6, TNF-α, MMP-3, MMP-13 and VEGF, whereas the application of non-degenerated AF-exo demonstrated inverse effects.
These results showed that AF-exo is an essential regulator mediating intercellular communication between AF cells and HUVECs, suggesting its important role in vascularization in the intervertebral disc.
椎间盘是人体最大的无血管器官。椎间盘的血管生成通常被认为是椎间盘退变（IDD）的病理特征。然而，IDD 中血管生成的潜在机制尚不清楚。本研究旨在探讨 AF 细胞衍生的外泌体（AF-exo）在与人脐静脉内皮细胞（HUVEC）相互作用中的作用及其在调节 IDD 中血管生成中的潜在作用。
从 IDD 和特发性脊柱侧凸患者中获得人 AF 组织。通过透射电子显微镜（TEM）、纳米颗粒转运分析（NTA）和 Western blot 鉴定 AF-exo。然后，将 AF-exo 用于 HUVECs 培养。观察 2D 和 3D 培养中 HUVECs 的迁移。通过实时 PCR 和酶联免疫吸附试验（ELISA）检测 HUVECs 的炎症表型。此外，通过流式细胞术分析 HUVECs 的凋亡。
在这里，我们首次发现 AF 细胞可以分泌 AF-exo，并且 HUVECs 可以吞噬 AF-exo。此外，我们发现退变的 AF-exo 通过促进细胞迁移（在 2D 和 3D 培养中）和炎症因子表达（包括 IL-6、TNF-α、MMP-3、MMP-13 和 VEGF）对 HUVECs 发挥促血管生成作用，而非退变的 AF-exo 则表现出相反的作用。
这些结果表明，AF-exo 是介导 AF 细胞与 HUVEC 之间细胞间通讯的重要调节剂，提示其在椎间盘血管生成中具有重要作用。
