外泌体介导的T细胞和巨噬细胞对话在腹主动脉瘤发生中的作用和T细胞迁移RNA甲基化新机制

One of the main pathogenic factors of abdominal aortic aneurysm (AAA) is inflammation. Most previous studies focused on the direct regulation of AAA risk factors on immune cells, especially T cells or macrophages respectively. The role of cellular crosstalk in AAA is unclear. From the RNA methylation and exosome metabolic reprogramming perspective, this project will use acquired NSun2+/- and T cell specific pyruvate kinase muscle isozyme 2 (PKM2) knockout mice and apply LC-MS/MS metabolomics, nanomaterial quantum dots for cell-targeting transport, cell and molecular biology and immunology research methods to explore: (1) The molecular mechanisms of T cell PKM2-mediated exosome release and then activating M1 macrophages polarization and therefore triggering AAA; (2) The mechanism of tRNA methyltransferase NSun2 regulating PKM2 expression and promoting T cells activation and migration; (3) Combined with the results of the next-generation sequencing of exosomes, quantum dots were packaged with exosomes or new targets to achieve cell-targeting intervention and consequently relieve AAA in vivo; (4) Clinical samples of AAA patients preliminarily verified part of the research results. This study will provide new intervention strategies for macrophage activation-related diseases.

腹主动脉瘤（AAA）发病的主要因素之一是炎症免疫。以往多数研究是AAA危险因素对免疫细胞，尤其是分别对T细胞或巨噬细胞直接的调控作用。细胞间对话及其方式与AAA的关系尚不清楚。本项目利用已获得的NSun2+/-和T细胞特异敲除PKM2的小鼠，从RNA甲基化以及外泌体代谢重塑的新角度，采用LC-MS/MS代谢组学、纳米量子点细胞靶向传输、细胞和分子生物学以及免疫学研究手段探究：（1）T细胞PKM2表达介导其释放外泌体而激活巨噬细胞M1极化，引发AAA的分子机制；（2）细胞核内tRNA甲基转移酶NSun2调控PKM2表达而激活T细胞并迁移的机制；（3）结合外泌体二代基因测序结果，将纳米量子点包装外泌体或新靶标以实现在体靶向干预而缓解AAA；（4）临床AAA病人样本初步验证部分研究结果，也为巨噬细胞激活的相关疾病提供新的干预策略。

腹主动脉瘤（AAA）发病的主要机制之一是炎症免疫。本项目采用LC-MS/MS代谢组学、细胞和分子生物学以及免疫学研究手段系统阐述了RNA甲基转移酶NSun2促进血管内皮细胞自分泌运动因子（ATX）的表达并招募T淋巴细胞而促进血管炎症和AAA；T细胞M2型丙酮酸激酶（PKM2）介导其分泌富含活性脂质的外泌体促进巨噬细胞迁移而加速AAA；同时AAA作为外周动脉疾病的重要危险因素，我们在原计划的研究内容基础上，拓展了研究目标和意义，进一步采用单细胞测序、小鼠谱系示踪以及骨髓移植等技术，有了新的发现，即CD34源促再生成型成纤维细胞与巨噬细胞对话促进下肢缺血后修复。因此全面完成并适当拓展了原有研究目标，取得实质性进展。这些研究为AAA等外周动脉疾病的早期预警和诊疗提供了新的潜在靶点。