Liver Transplantation Center, Beijing Friendship Hospital, Capital Medical University, Beijing 101100, China; Clinical Center for Pediatric Liver Transplantation, Capital Medical University, Beijing 101100, China; National Clinical Research Center for Digestive Diseases, Beijing 101100, China.
Clinical Center for Pediatric Liver Transplantation, Capital Medical University, Beijing 101100, China; National Clinical Research Center for Digestive Diseases, Beijing 101100, China; Department of Critical Liver Diseases, Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing 101100, China.
Int Immunopharmacol. 2022 Aug;109:108787. doi: 10.1016/j.intimp.2022.108787. Epub 2022 Apr 28.
Graft-infiltrated dendritic cells (DCs) and CD8 T lymphocytes are closely related with immune regulation after liver transplantation (LT). An additional factor which appears to play an important role with regard to transplantation immunity are exosomes, which are membrane-derived small vesicles released by various cells. However, the regulation of CD80 DCs derived exosomes on CD8 T cells in response to LT remains unclear.
Ten LT patients and two donors were included in this study. Multiple immunofluorescencewas performed to identify infiltratedCD8 Tcells and DCs in human liver samples. The expression of NLRP3 and Ki-67 were measured usingimmunohistochemistry and immunofluorescence staining.Changes in CD80 DCs and CD8 T cells within the liver and blood of a mouse model of LT were detected with flow cytometry. After coculture with CD80 DCs derived exosomes, the proliferation, adhesion, and transmigration ofCD8 T cells were determined with the use of CCK-8, Adhesion and Transmigration assay in vitro.CD8 T cells related cytokines were measured using Western blot, qRT-PCR and ELISA.
In human liver samples, there was an increase in intrahepatic CD8 T cell infiltration in the acute LT rejection group, an effect which was accompanied by high expressions of NLRP3 and Ki-67 index and a decrease in DCs. Similarly, lower levels of CD80 DCs were observed with acute rejection in an LT mouse model, along with increased numbers of CD8 T cells in the liver and blood. In vitro, CD80 DCs derived exosomes modulated the secretion of CD8 T cells from cytokines by down-regulating NLRP3 expression, combined with a synchronous inhibition in the adhesion, invasion, and proliferation of CD8 T cells.
CD80 DCs derived exosomes negatively regulate CD8 T cells via inhibition of NLRP3 expression, a series of events which are essential to attenuate acute LT rejection. These results reveal a new role for CD80 DCs exosomes as related to tolerance induction in LT.
移植物浸润树突状细胞（DCs）和 CD8 T 淋巴细胞与肝移植（LT）后免疫调节密切相关。另一个似乎对移植免疫起重要作用的因素是外泌体，它是各种细胞释放的膜衍生的小囊泡。然而，CD80 DC 衍生的外体对 LT 反应中 CD8 T 细胞的调节尚不清楚。
本研究纳入 10 例 LT 患者和 2 名供者。采用多重免疫荧光法鉴定人肝组织中浸润的 CD8 T 细胞和 DCs。免疫组化和免疫荧光染色检测 NLRP3 和 Ki-67 的表达。采用流式细胞术检测 LT 小鼠模型肝内和血中外泌体 CD80 DCs 和 CD8 T 细胞的变化。体外共培养 CD80 DCs 衍生的外体后，用 CCK-8、粘附和迁移实验检测 CD8 T 细胞的增殖、粘附和迁移。采用 Western blot、qRT-PCR 和 ELISA 检测 CD8 T 细胞相关细胞因子。
在人肝组织样本中，急性 LT 排斥组肝内 CD8 T 细胞浸润增加，NLRP3 和 Ki-67 指数高表达，DCs 减少。同样，LT 小鼠模型急性排斥时观察到 CD80 DCs 水平降低，肝和血中 CD8 T 细胞增多。体外，CD80 DC 衍生的外体通过下调 NLRP3 表达调节 CD8 T 细胞细胞因子的分泌，同时同步抑制 CD8 T 细胞的粘附、侵袭和增殖。
CD80 DC 衍生的外体通过抑制 NLRP3 表达负调控 CD8 T 细胞，一系列事件对于减轻急性 LT 排斥至关重要。这些结果揭示了 CD80 DC 外体在 LT 中诱导耐受的新作用。
