Heterogeneity of fibroblasts from different anatomical sites in healthy human knee ligaments revealed by single-cell RNA sequencing

Knee ligaments are important structures that determine the locomotor function of the knee. In this paper, we identified and analyzed the cell types and compositions of ligaments from different parts of the healthy knee joint. By single-cell sequencing of approximately 106,077 extracted cells, we established a comprehensive cellular profile of ligaments in other parts of the knee joints of 15 healthy subjects and explored the more critical heterogeneity of fibroblasts. Three subpopulations of fibroblasts that may be associated with knee ligament anatomy were identified and their differentiation relationships were revealed, and the FTH1/FTL_SCARA5 signaling pathway that may be associated with knee ligament anatomical function was identified. This ligament atlas provides a molecular cytological basis for studying the physiological functions and properties of knee ligaments as well as the relationship between ligament structure and function at different sites. It offers certain clues for future studies of rated knee ligament diseases.