MSCs-exo经C3-CR2通路靶向抑制ICOSL+B细胞防治cGVHD的实验研究

MSCs来源外泌体（MSCs-exo）的无细胞治疗模式有望成为治疗cGVHD的新方法，我们前期发现MSCs-exo可有效改善cGVHD小鼠病理损伤,但其确切机制尚未完全阐明。ICOSL+B细胞可能是介导cGVHD免疫损伤新机制，而C3-CR2通路是其分化调控关键。我们预实验显示cGVHD患者体内ICOSL+B、C3、CR2表达升高，经MSCs-exo治疗后小鼠ICOSL+B细胞下降，且发现MSCs-exo富含miR-22-5p，CR2可能为其靶基因。因此，本项目拟探索并验证如下假说：MSCs-exo负载miR-22-5p，调控C3-CR2通路，进而抑制ICOSL+B细胞改善cGVHD的病理损伤。进一步通过CD19的scFv修饰MSCs-exo提高其抑制ICOSL+B细胞效率。研究成果有望为MSCs-exo临床干预cGVHD提供新策略。

The exosomes derived from mesenchymal stem cells (MSCs-exo), a new type of cell-free biological agent, may offer a promising therapeutic approach for cGVHD patients. We have previously reported that MSCs-exo therapy ameliorates the pathological damage in cGVHD mice, but the exact molecular mechanisms involved have not yet been fully elucidated. Our study reveals novel mechanistic insights of ICOSL+B cells-mediated regulation of immune injury, and the C3-CR2 signaling pathway is a critical regulator of its differentiation. Based on our preliminary in vitro results, we determined the increased expression levels of ICOSL +B cells, C3, and CR2 in cGVHD patients, and found ICOSL+B cells in mice tissues decreased after MSCs-exo treatment. We found that MSCs-exo is rich in miR-22-5p, in agreement with bioinformatics findings, and CR2 is the predicted target gene. Therefore, the following hypothesis is explored and verified in the project: miR-22-5p enriched in MSCs-exo could suppress the ICOSL+B cells via the C3-CR2 pathway, improve the pathological damage of cGVHD. Furthermore, the MSCs-exo modified by CD19 scFv improves the efficiency in inhibiting ICOSL+B cells. The expected results will provide a new strategy for MSCs-exo clinical intervention in cGVHD.