Fig. 1: scRNA-seq atlas of human NP tissues identifies six cell clusters.

a T2 MRI image of 7 samples of a single-cell sequence. (mild degenerative disc [MDD]: n = 4, severe degenerative disc [SDD]: n = 3). b Schematic workflow of the experimental design. Cells isolated from the NP of human IVDs were subjected to scRNA-seq. c Heatmap of marker genes of the 9 cell types. d UMAP map of the following 9 cell types: T cells, B cells, monocytes, macrophages, neutrophils, NPCs, endothelial cells, SMCs, and erythrocytes. e, f UMAP image of the NPC marker genes: ACAN and SOX9. g A single-cell atlas revealed the cell distributions and cell type distributions of NPCs. h–m The differentially expressed genes in each of the 6 NPC subclusters. n–q Representative IHC image with marker gene (UBE2C, FBLN1, CHI3L2, DKK1, MSMO1 and CP) expression of the 6 NPC clusters in MDD and SDD human tissue (n, p, scale bar: 200 µm left and 50 µm right panels) and in CTR and AFP group model mouse IVDs (o, q, scale bar: 200 µm up and 50 µm down panels). MDD mild degenerative discs, SDD severe degenerative discs, DEGs differentially expressed genes, UMAP uniform manifold approximation and projection, SMCs smooth muscle cells, red arrows: NPCs; CTR control groups, AFP annulus fibrosus puncture group, AF annulus fibrosus, CEP cartilaginous end plate, NP nucleus pulposus, IVD intervertebral disc. n = 5 each group. Data are presented as mean ± SD. Statistical significance was determined by two-tailed unpaired t test. Source data are provided as a Source Data file.