A Combination of Oxo-M and 4-PPBP as a potential regenerative therapeutics for tendon injury

Tendons injuries frequently result in scar-like tissue with poor biochemical structure and mechanical properties. We have recently reported that CD146 perivascular originated tendon stem/progenitor cells (TSCs), playing critical roles in tendon healing. Here, we identified highly efficient small molecules that selectively activate endogenous TSCs for tendon regeneration. : From a pool of ERK1/2 and FAK agonists, Oxo-M and 4-PPBP were identified, and their roles in tenogenic differentiation of TSCs and tendon healing were investigated. Controlled delivery of Oxo-M and 4-PPBP was applied via PLGA µS. Signaling studies were conducted to determine the mechanism for specificity of Oxo-M and 4-PPBP to CD146 TSCs. : A combination of Oxo-M and 4-PPBP synergistically increased the expressions of tendon-related gene markers in TSCs. , delivery of Oxo-M and 4-PPBP significantly enhanced healing of fully transected rat patellar tendons (PT), with functional restoration and reorganization of collagen fibrous structure. Our signaling study suggested that Oxo-M and 4-PPBP specifically targets CD146 TSCs via non-neuronal muscarinic acetylcholine receptors (AChR) and σ1 receptor (σ1) signaling. : Our findings demonstrate a significant potential of Oxo-M and 4-PPBP as a regenerative therapeutics for tendon injuries.