PGE2-Primed Mesenchymal Stem Cells Modulate Myofibroblast Function via Bidirectional Communication: A Proteomic Investigation into Equine Endometrial Fibrosis Reversal

Endometrosis is a prevalent fibrotic condition in mares that impairs reproductive efficiency by inducing aberrant transformation of endometrial stromal cells into myofibroblasts, leading to excessive extracellular matrix deposition. To elucidate the molecular mechanisms underlying fibrosis resolution, this study employed comprehensive proteomic techniques, including LC-MS/MS and SILAC, to analyze the interaction between myofibroblasts and mesenchymal stem cells derived from the endometrium (ET-eMSCs) preconditioned with PGE₂. An in vitro co-culture system was used, with samples collected at baseline and after 48 hours. Proteomic analysis identified significant alterations in proteins associated with extracellular matrix (ECM) remodeling, immune regulation, and cellular stress response. Notably, proteins involved in collagen degradation, antioxidant defense, and growth factor signaling pathways were differentially abundant. Network analyses demonstrated robust interactions among these proteins, suggesting coordinated modulatory effects. The data indicates that PGE₂-primed ET-eMSCs induce a shift in myofibroblast secretory profiles, promoting ECM “softening,” tissue reorganization, and activation of resolution pathways. These findings reinforce the therapeutic potential of mesenchymal stem cell-based interventions for fibrotic diseases of the endometrium, opening avenues for regenerative strategies to restore reproductive function in mares.