Single-cell atlas of human infrapatellar fat pad and synovium unravels mechanisms of osteoarthritis-induced joint pathology

Infrapatellar fat pad (IPFP) and synovium, two joint tissues next to each other, play essential roles in regulating joint homeostasis and the progression of knee osteoarthritis (OA). However, the mechanisms regulating their function under healthy and diseased conditions are largely unknown. This study aims to analyze the cellular heterogeneity of these two tissues from normal and OA patients. Single cell and single nuclei transcriptomic profiling were performed on IPFP/synovium cells from four healthy donors and five OA patients. Subsequent bioinformatic analyses identified cell clusters, delineated differentiation routes of mesenchymal cells and macrophages, and identified novel cell-to-cell communication pathways in joint tissue. IPFP/synovium cells from four healthy donors and five OA patients were harvest and analyzed by scRNA-seq