Osteoblast-derived mitochondria formulated with cationic liposome guide mesenchymal stem cells into osteogenic differentiation

While mitochondria are known to be essential for intracellular energy production and overall function, emerging evidence highlights their importance in influencing cell behavior intracellularly through mitochondrial transfer. This phenomenon provides a potential basis for the development of treatment strategies for tissue damage and degeneration and inhibition of tumor progression. This study aimed to evaluate whether mitochondria isolated from osteoblasts can promote osteogenic differentiation in mesenchymal stem cells (MSCs). We first compared mitochondria from MSCs, which primarily utilize glycolysis, with those from MG63 cells, which depend on OXPHOS. Mitochondria from both cell types were then encapsulated in cationic liposomes and transferred to MSCs and their impact on differentiation was assessed. Mitochondria delivery from MG63 cells to MSCs grown in both 2D and 3D cultures resulted in increased expression of osteogenic markers including RUNX2, OSX, and OPN and upregulation of genes involved in BMP2 signaling and calcium import. This was accompanied by increased calcium influx and regulated by the Wnt/b-catenin signaling pathway. Transplantation of spheroids containing MSCs with MG63-derived mitochondria in bone defect animal models improved bone regeneration. Our results suggest that delivery of MG63-derived mitochondria effectively guides MSCs toward osteogenesis, paving the way for the development of mitochondria-based therapies.