基于单细胞转录组学分析胰岛缺血性损伤分子机制及核心转录因子的鉴定

Analysis of the molecular mechanism of pancreatic islet ischemic injury and identification of core transcription factors based on single-cell transcriptomics

  • 摘要:
    目的  探讨胰岛移植损伤过程中的分子机制和细胞间相互作用。
    方法 使用炎症因子处理的小鼠胰岛的单细胞转录组数据,基于Seurat包进行数据处理,并通过整合数据以去除批次效应。根据已知标志物对各个细胞亚群进行注释。基于CellChat包对炎症因子处理组中的细胞互作进行分析,基于细胞表面受体和配体的表达情况推断细胞间的相互作用。使用基因集富集分析明确炎症因子处理后β细胞中富集的生物过程。最后鉴定出差异表达的转录因子,并使用供者胰岛缺血性损伤的微阵列数据集以及蛋白质印迹法进行验证。
    结果 在小鼠胰岛中共发现了7个不同的细胞亚群,其中β细胞占据的比例最大。细胞互作网络分析结果显示,导管细胞与其他细胞之间的相互作用数量和强度最高。基因集富集分析结果显示,炎症因子处理后,β细胞中的免疫反应正向富集,而肽类激素、胆汁酸代谢以及离子稳态下调。在小鼠的单细胞转录和供者胰岛缺血性损伤的微阵列数据集中鉴定出共同的差异转录因子早期生长反应因子1(EGR1)、核因子-κB抑制因子α(NFKBIA)、转录激活因子3(ATF3)。其中,NFKBIA、ATF3表达上调,EGR1表达下调。EGR1蛋白表达量在冷缺血24 h、48 h及72 h后下调。
    结论  EGR1为与胰岛冷缺血密切相关的转录因子,未来的研究应重点探讨EGR1及其下游靶基因的具体机制,以期为胰岛移植的临床治疗提供更有效的策略。

     

    Abstract:
    Objective To explore the molecular mechanisms and cell-cell interactions in the injury process of pancreatic islet transplantation.
    Methods Single-cell transcriptome data from mouse islets treated with inflammatory factors were used, and data processing was performed using the Seurat package, with integrated data to remove batch effects. Cell subpopulations were annotated based on known markers. Cell-cell interactions in the inflammatory factor-treated group were analyzed using the CellChat package, and inferred based on the expression of cell surface receptors and ligands. Gene set enrichment analysis was used to clarify the biological processes enriched in β-cells after treatment with inflammatory factors. Finally, differentially expressed transcription factors were identified and verified using microarray datasets of donor islet ischemic injury and Western blotting.
    Results A total of 7 different cell subpopulations were found in mouse islets, with β-cells being the most abundant. Cell-cell interaction network analysis showed that the number and strength of interactions between ductal cells and other cells were the highest. Gene set enrichment analysis showed that after treatment with inflammatory factors, the immune response was positively enriched in β-cells, while peptide hormone metabolism, bile acid metabolism, and ion homeostasis were downregulated. The common differential transcription factors identified in the mouse single-cell transcriptome and the microarray dataset of donor islet ischemic injury were early growth response 1 (EGR1), nuclear factor-κB inhibitor α (NFKBIA), and activating transcription factor 3 (ATF3). Among them, NFKBIA and ATF3 were upregulated, while EGR1 was downregulated. The expression of EGR1 protein was downregulated after 24 h, 48 h, and 72 h of cold ischemia. Conclusions EGR1 is a transcription factor closely related to islet cold ischemia, and future research should focus on the specific mechanisms of EGR1 and its downstream target genes, in order to provide more effective strategies for clinical treatment of islet transplantation.

     

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