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

ObjectiveType 2 diabetes mellitus (T2DM) is a complex polygenic disease. The onset of the disease is related to autoimmunity. However, how immune cells function in the peripheral blood remains to be elucidated. Metformin is the first-line treatment. Exploring biomarkers of T2DM based on single-cell sequencing technology can provide new insights for the discovery of metformin treatment T2DM in molecular mechanisms. MethodsWe profiled 43,971 cells and 20,228 genes from peripheral blood mononuclear cells (PBMCs) of T2DM patients and healthy controls by single-nucleotide RNA sequencing. ResultsB 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. Monocytes/macrophages include classic monocytes and nonclassical monocytes. The GSEA results showed that the marker genes were enriched in the HALLMARK_INTERFERON_GAMMA_RESPONSE and HALLMARK_TNFA_SIGNALING_VIA_NFKB. The WGCNA results showed 14 modules. 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. ConclusionsOur study revealed that the transcriptional map of immune cells from PBMCs provided a framework for understanding the immune status of T2DM patients with metformin treatment via scRNA-seq analysis.