Treatment of inflammatory bone loss in periodontitis by stem cell-derived exosomes

Periodontitis is the primary cause of tooth loss, but there is no effective treatment to repair inflammatory bone loss in periodontitis. Exosomes emerge as essential paracrine factors of mesenchymal stem cells (MSCs) that mediated tissue regeneration. Here, we investigated the potential of exosomes secreted by periodontal ligament stem cells (PDLSCs) as therapeutics for the bone defect in periodontitis. Exosomes secreted from PDLSCs derived from healthy periodontal ligaments (h-PDLSCs) and their function were evaluated on PDLSCs isolated from the inflammatory periodontal ligament of periodontitis patients (i-PDLSCs). Treatment of exosomes of h-PDLSCs led to an increase in the formation of mineralized nodules and the expressions of osteogenic genes and proteins in i-PDL SCs. Mechanistically, h-PDL SCs-exosomes suppressed the over-activation of canonical Wnt signaling to recover the osteogenic differentiation capac-ity of i-PDLSCs. To evaluate the therapeutic of exosomes on inflammatory bone loss, h-PDLSCs-exosomes loaded with Matrigel or beta-TCP were employed to repair bone defects in rat models of periodontitis. Com-pared to the vehicle-treated control group, h-PDLSCs-exosomes-treated rats resulted in more bone forma-tion in the defect of alveolar bone. In conclusion, these results demonstrated that exosomes derived from healthy PDLSCs could rescue the osteogenesis capacity of endogenous stem cells under an inflammatory environment and promote regeneration of alveolar bone. Our findings suggest that MSCs-derived exosome is an effective and practical cell-free MSC therapeutic for the treatment of periodontitis. Statement of significance There is no effective treatment to repair inflammatory bone loss in periodontitis. As essential paracrine factors of PDLSCs, exosomes might mediate tissue regeneration during stem cell therapy. Here, we re-ported that exosomes secreted from healthy PDLSCs promoted the osteogenic differentiation of PDLSCs derived from periodontitis tissue. Healthy PDLSCs-exosomes treatment resulted in accelerated bone for-mation in the defect of alveolar bone in rat models of periodontitis. Mechanistically, h-PDLSCs-exosomes suppressed the over-activation of canonical Wnt signaling to recover the osteogenic differentiation ca-pacity of inflammatory PDLSCs. These findings suggest that MSCs-derived exosome is an effective and practical cell-free MSC therapeutic for the treatment of periodontitis. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

Exosomes secreted by healthy periodontal ligament stem cells (PDLSCs) promote osteogenic differentiation of PDLSCs derived from periodontitis tissue. Treatment with exosomes can accelerate bone formation in rat models of periodontitis. Mechanistically, exosomes suppress over-activation of the canonical Wnt signaling pathway to recover the osteogenic differentiation capacity of inflammatory PDLSCs. These findings suggest that MSC-derived exosomes are an effective and practical cell-free therapeutic for the treatment of periodontitis.