Hypoxic TCs-Preconditioned MSCs Ameliorate Acute Lung Injury via Enhanced Treg Recruitment and Function Through CXCL5/6-CXCR1 Axis

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) remains a critical respiratory condition with limited effective treatments. This study investigated whether mesenchymal stem cells (MSCs) preconditioned with supernatant from hypoxia-cultured telocytes (TCs) could enhance therapeutic efficacy in ALI through regulatory T cell (Treg) modulation. MSCs preconditioned with 5% hypoxic TC supernatant demonstrated superior efficacy in ameliorating LPS-induced lung injury compared to conventional MSCs or TC monotherapy, as evidenced by preserved alveolar architecture, reduced inflammatory infiltration, and decreased pro-inflammatory cytokines. Mechanistically, these preconditioned MSCs significantly enhanced Treg recruitment to injured lung tissues and improved their immunosuppressive function through the CXCL5/6-CXCR1 axis, an effect that was substantially attenuated upon siRNA-mediated disruption of this pathway, and was further corroborated in a humanized ALI mouse model where preconditioned-MSC treatment improved survival, reduced lung injury severity, and enhanced Treg recruitment and function in a CXCL5/6 signaling-dependent manner. These findings reveal a novel mechanism by which hypoxic TC supernatant enhances MSC therapeutic efficacy in ALI through the CXCL5/6-CXCR1 axis, providing a promising strategy for optimizing cellular therapy in inflammatory pulmonary disorders.