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.