Single-cell RNA-seq of the tendon enthesis cells

Our studies used scRNA-seq analysis to get a full map of transcriptional profiles of enthesis cells and also a seprate Gli1-lineage enthesis stem cells. By harvesting enthesis cells from different development stages for scRNA-seq analysis, we revealed enthesis cell heterogeneity and identified six cell sub-populations using scRNA-seq. We infered cell differentiation trajectories for enthesis stem cells differentiating into mineralizing chondrocytes. A gene regulatory network analysis combined fluorescent in situ hybridization were then used to identify a number of transcription factors coordinating tenogenesis, chondrogenesis, and osteogenesis to form an enthesis with spatially graded mineralization.To further define the enthesis stem cell population, enthesis Gli1-lineage cells were isolated and their transcriptomes were characterized at single cell resolution. These specific Gli1-responsive cells had a linear trajectory and a capacity of chondrogenesis and osteogenesis. The full characterization of transcriptional landscape of tendon enthesis stem cells demonstrates a promising therapeutic strategies using this cell source for enthesis regeneration. Overall design: mRNA profiles of of tendon enthesis at P11, P18, and P56 old wild type (WT); mRNA profiles of Gli1-lineage cells at P7, P11, P14, P18, P21, P28, and P42