Application of Intracellular Vesicles Surpass Extracellular Vesicles in Regenerative Repair of Inflammatory Bone Defects via the LAMA4-Mediated YAP/TAZ Signalling

Periodontitis-induced inflammatory microenvironment compromises the function of periodontal ligament stem cells (PDLSCs) and significantly impedes the regeneration of periodontal tissues. Meanwhile, the clinical application of extracellular vesicles (EVs) is constrained by their low yield and high production costs. For the first time, this study systematically compares the functional differences between intracellular vesicles (IVs) and EVs derived from human PDLSCs (hPDLSCs) in promoting bone regeneration under inflammatory conditions, while also elucidating their underlying molecular mechanisms. IVs were produced with 6.9-fold higher efficiency and exhibited superior cellular uptake compared to EVs. In vitro, under lipopolysaccharide (LPS)-induced inflammatory environment, IVs outperformed EVs in enhancing the hPDLSCs proliferation, suppressing the secretion of pro-inflammatory cytokines (IL-6 and TNF-α) and upregulating osteogenic markers through Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) activation, thereby promoting calcium nodule formation. Proteomic and functional analyses identified laminin subunit alpha 4 (LAMA4) as a key effector enriched in IVs, which is essential for activating YAP/TAZ signalling and osteogenesis. Correspondingly, in vivo, IVs-loaded gel effectively promoted bone regeneration in rat periodontal bone defects without organ toxicity. This study establishes IVs as a superior, high-yield cell-free therapeutic and delineates an LAMA4-dependent mechanism via YAP/TAZ activation for inflammatory bone regeneration.