<b>Supporting data for "Utilization of Lgr5+ interzone cells in knee joint development for Achilles tendon repair"</b>

<p dir="ltr">This dataset supports my PhD thesis investigating the role of Lgr5+ progenitor cells in the development and repair of the Achilles tendon. Tendinopathy is common among elderly individuals and athletes, with impaired healing that adversely affects quality of life. Lgr5 and Lgr6 are recognized markers for stem cells, and our recent findings have identified Lgr5+ cells in the developing knee joint and Achilles tendon. The expression patterns of Lgr5 and Lgr6 during Achilles tendon development are dynamic, with both cell types present in early postnatal tendons. However, Lgr5+ cells become undetectable beyond 4 weeks of age, while Lgr6+ cells persist into adulthood. This suggests a specific role for Lgr5+ cells in tendon development and growth.</p><p dir="ltr">Age-related decline in tendon healing may be associated with the reduction or absence of Lgr5+ cells. Our study proposes that Lgr5+ progenitor cells are critical for the repair potential of tendons in young mice. Notably, we observed sporadic reactivation of Lgr5-GFP+ cells during tendon healing in adult mice, particularly at 7 days post-injury, suggesting a reparative role for these cells. To further explore the therapeutic potential of Lgr5+ cells, we transplanted exogenous Lgr5-GFP+ tdTomato+ cells (isolated from embryonic knee joint interzone) encapsulated in hydrogel into injured Achilles tendons. One week post-surgery, these transplanted cells were detected within the repaired tendon tissue, aligned with collagen fibers, indicating successful engraftment and a contribution to tissue repair.</p><p dir="ltr">This dataset includes experimental data on Lgr5 and Lgr6 expression during tendon development, injury, and repair, as well as information on the transplantation and engraftment of Lgr5+ cells. The dataset can be used to further investigate the cellular and molecular mechanisms underlying tendon healing and to evaluate the therapeutic potential of stem cell-based interventions for tendinopathy.</p>