1. Academic Validation
  2. Exosomal PD-L1 functions as an immunosuppressant to promote wound healing

Exosomal PD-L1 functions as an immunosuppressant to promote wound healing

  • J Extracell Vesicles. 2019 Dec 27;9(1):1709262. doi: 10.1080/20013078.2019.1709262.
Dandan Su 1 Hsiang-I Tsai 1 Zhanxue Xu 1 Fuxia Yan 1 Yingyi Wu 1 Youmei Xiao 1 Xiaoyan Liu 1 Yanping Wu 1 Sepideh Parvanian 2 Wangshu Zhu 3 John E Eriksson 2 Dongqing Wang 4 Haitao Zhu 4 Hongbo Chen 1 Fang Cheng 1
Affiliations

Affiliations

  • 1 School of pharmaceutical sciences (Shenzhen), Sun Yat-sen University, Shenzhen, China.
  • 2 Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland.
  • 3 Department of Radiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
  • 4 Department of medical imaging, The Affiliated Hospital of Jiangsu University, Zhenjiang, China.
Abstract

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.

Keywords

PD-L1; exosomes; immunotherapy; thermoresponsive hydrogel; wound healing.

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