Exosomes from TNF-α-treated human gingiva-derived MSCs enhance M2 macrophage polarization and inhibit periodontal bone loss

Mesenchymal stem cell (MSC)-derived exosome plays a central role in the cell-free therapeutics involving MSCs and the contents can be customized under disease-associated microenvironments. However, optimal MSC-preconditioning to enhance its therapeutic potential is largely unknown. Here, we show that preconditioning of gingival tissue-derived MSCs (GMSCs) with tumor necrosis factor-alpha (TNF-alpha) is ideal for the treatment of periodontitis. TNF-alpha stimulation not only increased the amount of exosome secreted from GMSCs, but also enhanced the exosomal expression of CD73, thereby inducing antiinflammatory M2 macrophage polarization. The effect of GMSC-derived exosomes on inflammatory bone loss were examined by ligature-induced periodontitis model in mice. Local injection of GMSC-derived exosomes significantly reduced periodontal bone resorption and the number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts, and these effects were further enhanced by preconditioning of GMSCs with TNF-alpha. Thus, GMSC-derived exosomes also exhibited anti-osteoclastogenic activity. Receptor activator of NF-kappa B ligand (RANKL) expression was regulated by Wnt5a in periodontal ligament cells (PDLCs), and exosomal miR-1260b was found to target Wnt5a-mediated RANKL pathway and inhibit its osteoclastogenic activity. These results indicate that significant ability of the TNF-alpha-preconditioned GMSC-derived exosomes to regulate inflammation and osteoclastogenesis paves the way for establishment of a therapeutic approach for periodontitis. Statement of significance Therapeutic effect of mesenchymal stem cell (MSC) largely depends on the paracrine efficiency of MSC, and gingiva-derived MSC (GMSC) have unique capacity to secret large amount of exosomes and, moreover, are easier to isolate. Recent studies indicated that appropriate preconditioning of MSC with disease-related stimuli can optimize the exosomal protein or miRNA contents which may efficiently support the healing and repair of specific diseases. In this study, we examined the therapeutic effects of TNF-alpha preconditioned-GMSC-derived exosomes on periodontal disease, and show for the first time an optical protocol for MSC-preconditioning targeting both exosomal proteinand miRNA-mediated attenuation of inflammation and osteoclastogenesis. These findings prove a therapeutic strategy for patients not only with periodontitis but with other inflammatory osteoimmune disorders. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd.

Automated summary

Preconditioning gingival tissue-derived MSCs (GMSCs) with tumor necrosis factor-alpha (TNF-alpha) enhances the secretion of exosomes and the expression of CD73, promoting antiinflammatory M2 macrophage polarization. GMSC-derived exosomes exhibit significant ability to regulate inflammation and osteoclastogenesis, providing a potential therapeutic approach for periodontitis. The findings suggest a promising strategy for treating inflammatory osteoimmune disorders using TNF-alpha-preconditioned GMSC-derived exosomes.