Single-cell RNA sequencing of peripheral blood mononuclear cells reveals complex cellular signalling signatures of type 2 diabetes mellitus

The onset of the Type 2 diabetes mellitus (T2DM) is related to autoimmunity. Exploring biomarkers of T2DM based on single-cell sequencing technology can provide new insights for the molecular mechanisms. B cells, T cells, monocytes/macrophages, platelets, neutrophils, NK cells and cDC2s were grouped into 7 subclusters. Furthermore, T cells and monocytes/macrophages might be significantly correlated with the clinical characteristics of T2DM patients. RPL27 and AC018755.4 expression were strongly negative correlated with HbA1c. CD4+ T cells are mainly in the memory activation stage, and CD8+ T cells are effectors. The 50 genes whose expression varied with developmental time were associated with cytoplasmic translation, cell?cell adhesion mediated by integrin, and the regulation of the inflammatory response. The GSEA results showed that the marker genes were enriched in the HALLMARK_INTERFERON_GAMMA_RESPONSE and HALLMARK_TNFA_SIGNALING_VIA_NFKB. Meanwhile, TNFRSF1A is the most core genes in network interaction . Further analysis revealed ligand?receptor pairs, including MIF- (CD74 + CD44), MIF- (CD74 + CXCR4), ANXA1-FPR1 and LGALS9-CD45. Conclusions: Our study revealed that the transcriptional map of immune cells from PBMCs provided a framework for understanding the immune status via scRNA-seq analysis. Overall design: We profiled 43,971 cells and 20,228 genes from peripheral blood mononuclear cells (PBMCs) of T2DM patients (Mod, treat) and healthy controls (Con) by single-nucleotide RNA sequencing.

2型糖尿病（Type 2 diabetes mellitus, T2DM）的发病与自身免疫密切相关。基于单细胞测序技术（single-cell sequencing technology）探索T2DM的生物标志物，可为解析其分子机制提供全新视角。本研究将B细胞、T细胞、单核细胞/巨噬细胞、血小板、中性粒细胞、自然杀伤细胞（NK cells）以及经典树突状细胞2型（cDC2s）划分为7个亚群。进一步分析显示，T细胞与单核细胞/巨噬细胞或与T2DM患者的临床特征存在显著关联。RPL27与AC018755.4的表达水平与糖化血红蛋白（HbA1c）呈显著负相关。CD4阳性T细胞（CD4+ T cells）主要处于记忆活化阶段，而CD8阳性T细胞（CD8+ T cells）则为效应性T细胞。50个随发育时间动态表达的基因，其功能富集于细胞质翻译、整合素介导的细胞黏附以及炎症反应调控等生物学过程。基因集富集分析（Gene Set Enrichment Analysis, GSEA）结果显示，标志性基因富集于特征集干扰素γ应答（HALLMARK_INTERFERON_GAMMA_RESPONSE）以及特征集肿瘤坏死因子α经核因子κB信号通路（HALLMARK_TNFA_SIGNALING_VIA_NFKB）。与此同时，肿瘤坏死因子受体超家族成员1A（TNFRSF1A）是网络互作中的核心枢纽基因。进一步的配体-受体互作分析揭示了多组配体-受体对，包括MIF-(CD74+CD44)、MIF-(CD74+CXCR4)、ANXA1-FPR1以及LGALS9-CD45。结论：本研究通过单细胞RNA测序（single-cell RNA sequencing, scRNA-seq）分析，明确了外周血单个核细胞（peripheral blood mononuclear cells, PBMCs）中免疫细胞的转录图谱，为解析机体免疫状态提供了研究框架。实验设计：本研究通过单核苷酸RNA测序技术，对T2DM患者（分为Mod、treat组）与健康对照组（Con）的外周血单个核细胞（PBMCs）完成了表达谱分析，共获取43971个细胞及20228个基因的表达谱数据。