外泌体程序性死亡配体1作为一种免疫抑制剂促进伤口愈合。
Exosomal PD-L1 functions as an immunosuppressant to promote wound healing.
作者信息
Su Dandan, Tsai Hsiang-I, Xu Zhanxue, Yan Fuxia, Wu Yingyi, Xiao Youmei, Liu Xiaoyan, Wu Yanping, Parvanian Sepideh, Zhu Wangshu, Eriksson John E, Wang Dongqing, Zhu Haitao, Chen Hongbo, Cheng Fang
机构信息
School of pharmaceutical sciences (Shenzhen), Sun Yat-sen University, Shenzhen, China.
Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland.
出版信息
J Extracell Vesicles. 2019 Dec 27;9(1):1709262. doi: 10.1080/20013078.2019.1709262.
Excessive and persistent inflammation after injury lead to chronic wounds, increased tissue damage or even aggressive carcinogenic transformation. Effective wound repair could be achieved by inhibiting overactive immune cells to the injured site. In this study, we obtained high concentration of PD-L1 in exosomes from either genetically engineered cells overexpressing PD-L1 or IFN-γ stimulated cells. We found that exosomal PD-L1 is specially bound to PD-1 on T cell surface, and suppressed T cell activation. Interestingly, exosomal PD-L1 promoted the migration of epidermal cells and dermal fibroblasts when pre-incubated with T cells. We further embedded exosomes into thermoresponsive PF-127 hydrogel, which was gelatinized at body temperature to release exosomes to the surroundings in a sustained manner. Of importance, in a mouse skin excisional wound model, exosomal PD-L1 significantly fastened wound contraction and reepithelialization when embedded in hydrogel during inflammation phase. Finally, exosomal PD-L1 inhibited cytokine production of CD8+ T cells and suppressed CD8+ T cell numbers in spleen and peripheral lymph nodes. Taken together, these data provide evidence on exosomal PD-L1 exerting immune inhibitory effects and promoting tissue repair.
损伤后过度且持续的炎症会导致慢性伤口、组织损伤加剧甚至引发侵袭性致癌转化。通过抑制免疫细胞过度活跃至损伤部位,可实现有效的伤口修复。在本研究中,我们从过表达PD-L1的基因工程细胞或IFN-γ刺激的细胞中获得了高浓度的外泌体PD-L1。我们发现外泌体PD-L1特异性结合T细胞表面的PD-1,并抑制T细胞活化。有趣的是,当与T细胞预孵育时,外泌体PD-L1促进表皮细胞和真皮成纤维细胞的迁移。我们进一步将外泌体包埋于温敏性PF-127水凝胶中,该水凝胶在体温下凝胶化,以持续的方式将外泌体释放到周围环境中。重要的是,在小鼠皮肤切除伤口模型中,在炎症期将外泌体PD-L1包埋于水凝胶中时,可显著加快伤口收缩和上皮再形成。最后,外泌体PD-L1抑制CD8+T细胞的细胞因子产生,并抑制脾脏和外周淋巴结中CD8+T细胞的数量。综上所述,这些数据为外泌体PD-L1发挥免疫抑制作用和促进组织修复提供了证据。