M2 macrophage-derived mitochondrial transplantation promotes periodontal bone regeneration by regulating metabolic homeostasis via activating p38-MAPK signaling pathway.

backgroundResearch indicates that the mitochondrial function of mesenchymal stem cells in the periodontal inflammatory microenvironment is impaired, leading to insufficient osteogenic differentiation. Mitochondrial transplantation has emerged as a promising treatment for mitochondrial dysfunction. In this study, we transplant M2 macrophage-derived mitochondria (M2-MT) into human periodontal ligament stem cells (hPDLSCs) in inflammatory states, and investigate its effect on the regulation and mechanism of osteogenic differentiation and metabolic status of hPDLSCs.

methodsThe inflammatory microenvironment was constructed by P.g-LPS. After isolating and inducing functional M2-MT and co-culturing them with hPDLSCs under inflammatory states, the expression levels of osteogenesis-related genes and proteins such as ALP, RUNX2, OCN were detected, the impact of M2-MT on the osteogenic differentiation ability of hPDLSCs under inflammatory conditions was also investigated. RNA seqencing was used to observe the expression of differentially expressed genes, and explore the underlying mechanisms. By detecting changes of ROS, MMP, ATP, and ECAR, the mitochondrial function and metabolic levels of hPDLSCs were observed. Finally, in vivo experiments further validated the promoting effect of M2-MT transplantation on bone tissue regeneration in periodontal disease rats.

resultsM2-MT with full function have been successfully extracted and internalized by hPDLSCs. Compared to P.g-LPS group, osteogenesis-related markers of hPDLSCs were significantly increased at both the mRNA and protein levels after M2-MT transplantation. RNA-seq results and verify experiments demonstrate that the p38-MAPK signaling pathway may play a role in this process. Furthermore, the ROS levels of inflammation affected hPDLSCs were reduced, the membrane potential increased, and ATP synthesis was enhanced. Seahorse cell energy metabolism analysis showed the ECAR level in the P.g-LPS group increased. The Micro-CT data from in vivo research showed the ABC-CEJ, BV/TV, Tb.N and Tb.Th were significantly improved after M2-MT transplantation. M2-MT transplantation can alleviate the inflammatory infiltration in the periodontal tissues and enhance the levels of osteogenic markers such as ALP, RUNX2, and OCN in periodontitis rats.

conclusionM2-MT transplantation can promote periodontal bone regeneration by regulate metabolic homeostasis and osteogenic differentiation of hPDLSCs via activating p38-MAPK signaling pathway. Our studies may provide a more minimally invasive and precise treatment method for periodontal tissue regeneration.