Fig. 1: Single-cell transcriptome analysis revealed MDSC signature genes.

A Experimental design schematic. In summary, CD11b⁺ Gr1⁺ myeloid cells were sorted from the bone marrow of both young and aged mice by FACS. And then all samples were processed using the 10X Genomics Chromium platform. B, C A total of 23,143 cells were finally analyzed. The UMAP projection result showed 23 distinct clusters in CD11b⁺ Gr1⁺ myeloid cells, and the main cell types included neutrophils, monocytes, T cells and B cells, based on the expression of marker genes. D The widely acknowledged MDSC marker genes Arg2, Cd84, Wfdc17, Jaml, Stat3 and Cd33 were utilized to identify both PMN-MDSCs and M-MDSCs, derived respectively from neutrophils and monocytes. E PMN-MDSCs were identified using the MDSC marker genes Arg2, Stat3, Jaml, Wfdc17, Irf1 in neutrophils. F M-MDSCs were identified using the MDSC marker genes S100a8, S100a9, Arg2, Tnf, Jaml in monocytes. G Heat map showing top 10 marker genes for each neutrophil subset. H The percentage of PMN-MDSCs found in the neutrophils of aged mice was higher than that of young mice. I Heat map showing top 10 marker genes for each monocyte subset. J The percentage of M-MDSCs found in the monocytes of aged mice was higher than that of young mice. K The Venn diagram illustrated the quantity of genes that were significantly differentially expressed in PMN-MDSCs and M-MDSCs, showing an overlap of 472 genes shared between these two MDSC subsets. L Gene ontology analysis of the MDSC signature genes. M RT-qPCR validated the expression levels of some MDSC signature genes. Data were presented as the mean ± SD. *P < 0.05.