Exosomal miR‐205‐5p derived from periodontal ligament stem cells attenuates the inflammation of chronic periodontitis via targeting XBP1

INTRODUCTION: Chronic periodontitis (CP) is an inflammatory periodontal disease with high incidence and complex pathology. This research is aimed to investigate the function of exosomal miR‐205‐5p (Exo‐miR‐205‐5p) in CP and the underlying molecular mechanisms. METHOD: Exo‐miR‐205‐5p was isolated from miR‐205‐5p mimics‐transfected periodontal ligament stem cells (PDLSCs), and subsequently cocultured with lipopolysaccharide (LPS)‐induced cells or injected into LPS‐treated rats. The mRNA expression of inflammatory factors and Th17/Treg‐related factors were measured by quantitative real‐time PCR. The contents of inflammatory factors and the percentages of Th17/Treg cells were measured by enzyme‐linked immunosorbent assay and flow cytometry, respectively. Besides, the target relation between miR‐205‐5p and X‐box binding protein 1 (XBP1) was explored. RESULTS: MiR‐205‐5p was downregulated in LPS‐induced PDLSCs and corresponding exosomes. Exo‐miR‐205‐5p inhibited inflammatory cell infiltration, decreased the production of TNF‐α, IL‐1β, and IL‐6, and decreased the percentage of Th17 cells in LPS‐treated rats. In addition, XBP1 was a target of miR‐205‐5p. Overexpression of XBP1 weakened the effects of Exo‐miR‐205‐5p on inhibiting inflammation and regulating Treg/Th17 balance in LPS‐induced cells. CONCLUSIONS: Exo‐miR‐205‐5p derived from PDLSCs relieves the inflammation and balances the Th17/Treg cells in CP through targeting XBP1.