Qian Wenwei, Huang Liangyu, Xu Yihan, Lu Wen, Wen Weiwei, Guo Zhen, Zhu Weiming, Li Yi
Department of General Surgery, Jinling Hospital, Medical School of Southeast University, Nanjing, PR China.
Department of Colorectal Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, PR China.
Inflamm Bowel Dis. 2023 Apr 3;29(4):602-619. doi: 10.1093/ibd/izac225.
Exosomes derived from mesenchymal stem cells have shown therapeutic effects for colitis. As a more clinically accessible resource, the therapeutic potential of exosomes from adipose-derived stem cells (ASCs) has not been fully elucidated, and whether hypoxia precondition could improve the therapeutic effect of ASC-derived exosomes in colitis remains elusive.
In this study, exosomes were derived from ASCs under normoxia (NExos) and hypoxia (HExos) and were identified by detecting their morphology, size distribution, and exosome surface markers. The concentration of inflammation-related cytokines was detected by ELISA, and macrophage phenotype-related genes were determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), western blot, and immunofluorescence. A miRNA microarray sequencing analysis was conducted to confirm the differentially expressed miRNAs. Dextran sulfate sodium-induced colitis was employed as an in vivo assay.
Administration of NExos alleviated inflammation by modulating the balance of macrophages both in cellular assays and in vivo experiments, and HExos showed higher therapeutic efficiency than NExos. The miR-216a-5p in HExos was significantly enriched and promoted macrophage M2 polarization through transfer to macrophages by exosomes. The miR-216a-5p was confirmed to target the 3'-UTR of HMGB1. Mechanistically, hypoxia-induced ASCs release miR-216a-5p in an exosomal way that induced macrophage M2 polarization by regulating the HMGB1/TLR4/NF-κB signaling pathway.
Exosomal miR-216a-5p released from hypoxia-prime ASCs showed higher therapeutic efficiency than NExos in experimental colitis by promoting the M2 macrophage phenotype, which indicated that hypoxia prime may represent a promising approach to optimizing the function of ASC-derived exosomes.
间充质干细胞来源的外泌体已显示出对结肠炎的治疗作用。作为一种在临床上更易获取的资源，脂肪来源干细胞（ASC）分泌的外泌体的治疗潜力尚未完全阐明，低氧预处理是否能提高ASC来源外泌体对结肠炎的治疗效果仍不清楚。
在本研究中，从常氧（NExos）和低氧（HExos）条件下的ASC中提取外泌体，并通过检测其形态、大小分布和外泌体表面标志物进行鉴定。采用酶联免疫吸附测定（ELISA）检测炎症相关细胞因子的浓度，通过定量逆转录-聚合酶链反应（qRT-PCR）、蛋白质免疫印迹法（western blot）和免疫荧光法测定巨噬细胞表型相关基因。进行miRNA微阵列测序分析以确认差异表达的miRNA。采用葡聚糖硫酸钠诱导的结肠炎作为体内实验模型。
在细胞实验和体内实验中，NExos通过调节巨噬细胞平衡减轻炎症，且HExos显示出比NExos更高的治疗效率。HExos中的miR-216a-5p显著富集，并通过外泌体转移至巨噬细胞促进巨噬细胞M2极化。证实miR-216a-5p靶向HMGB1的3'-非翻译区（3'-UTR）。机制上，低氧诱导ASC以外泌体方式释放miR-216a-5p，通过调节HMGB1/TLR4/NF-κB信号通路诱导巨噬细胞M2极化。
低氧预处理的ASC释放的外泌体miR-216a-5p在实验性结肠炎中通过促进M2巨噬细胞表型显示出比NExos更高的治疗效率，这表明低氧预处理可能是优化ASC来源外泌体功能的一种有前景的方法。
