An atlas of cartilage in the distal radius generated via single-cell RNA sequencing reveals cell‒cell interaction patterns similar to those of the ankle.

Among the skeletal structures of the wrist joint, an articular disc exists between the cartilage of the distal ulna and carpus, whereas the cartilage of the distal radius almost directly contacts the carpus. In this study, articular cartilage tissues from the distal radius were obtained from donors, and scRNA-seq was conducted. This study provides deep insight into the articular cartilage of the distal radius. Five cartilage tissue samples from the distal radius were obtained from 5 donors, and scRNA-seq was conducted. To verify the distribution of each cell type, the samples were subjected to immunohistochemistry. Ultimately, 51,826 cells were analysed, and 11 cell types were annotated, including FC-A, FC-B, MirCs, SpCs, preHTCs, HTC-A, HTC-B, HomCs, ProCs, ImmCs, and RegCs. Cell‒cell interactions and specific TFs for chondrocyte subsets were identified, which indicate that ATF1, IRF3, KDM5B, and SMARCC2 are specific for SpCs, and ETS2, MXI1, CEBPB, and EGR1 were obviously expressed across cell types and samples. The FN1, COMP and CD99 pathways and cell‒cell interaction patterns of the distal radius may be similar to those of the ankle.