可降解泪道栓缓释MSC-Exo/CCR7-scFv靶向调控干眼眼表免疫炎症的研究

干眼是一种严重影响视功能和生活质量的疾病。眼表免疫介导的炎症反应是干眼发病的关键因素。树突状细胞（DCs）是启动眼表免疫应答的中心环节。间充质干细胞外泌体（MSC-Exo）对DCs有免疫调节功能，也是实现靶向给药的优良载体。前期研究中我们借鉴CAR-T原理，将含疏水跨膜段CCR7中和单链抗体（CCR7-scFv）直接锚定至MSC-Exo，构建CAR-Exo（MSC-Exo/CCR7-scFv），发现其可在体外抑制DCs成熟和趋化。因此，本项目拟探讨MSC-Exo/CCR7-scFv是否可在体内抑制DCs成熟的同时抑制DCs迁移至区域淋巴结，调控T细胞分化，进而抑制眼表炎症；并构建载药泪道栓缓释MSC-Exo/CCR7-scFv，评价其对干眼的疗效及机制。本项目研究的可降解载药泪道栓在堵塞泪道，缓解症状的同时对眼表免疫炎症的进行调控，是一种“标本兼治”的治疗方法，可为临床干眼治疗提供新方法。

Dry eye disease (DED) is a prevalent disease that greatly impairs visual function and negatively impacts quality of life. Ocular surface immune cell-mediated inflammation is considered to be the core pathogenetic factor of dry eye. DC plays a central role in the priming stage of ocular surface immume response. Blocking the activation and migration of DC can prevent the initiation and development of immune inflammation from the source. MSC-Exo can regulate the immune function of DC, as well as an excellent carrier of targeted drug delivery. In our preliminary study, we prepared a neutralizing single-chain antibody of CCR7(CCR7-scFv), containing a hydrophobic transmembrane segment, which could directly anchored CCR7-scFv onto MSC-Exo (MSC-Exo/CCR7-scFv). We found MSC-Exo/CCR7-scFv could selectively inhibit the maturation of DCs, as well as inhibit the CCL21 mediated DCs chemotaxis in vitro. Thus, in this study we explore whether MSC-Exo/CCR7-scFv could prevent DCs from maturation and migrating to regional lymph nodes, inhibit T cell differentiation, and then inhibit the ocular surface inflammation in vivo. Moreover, we fabricate degradable lacrimal plug loaded with MSC-Exo/CCR7-scFv. The therapeutic effect of this lacrimal plug and its underlying mechanism in modulating immune-inflammation on the ocular surface of dry eye are evaluated through a dry eye animal model. In summary, this drug-loaded lacrimal plug releaseing MSC-Exo/CCR7-scFv is intended to block lacrimal duct and to stabilize the osmolarity. Meanwhile, this plug is targeted to modulate the activation and migration of DCs by releasing MSC-Exo/CCR7-scFv, in the aim of blocking immune inflammatory cascade from the early stage, providing a more effective treatment for dry eye disease.