Epithelium-derived exosomal dipeptidyl peptidase-4 involved in arecoline-induced oral submucous fibrosis.

INTRODUCTION: Dipeptidyl peptidase-4 is known to be involved in the progression of several fibrogenic diseases, but its association with oral submucous fibrosis remains unclear. This study aims to ascertain whether dipeptidyl peptidase-4 plays a role in the pathogenesis of arecoline-induced oral submucous fibrosis. METHODS: We assessed the expression of dipeptidyl peptidase-4 in arecoline-treated epithelial cells and the exosomes derived from cells. We cocultured the fibroblast and exosomes derived from epithelium cells and assessed fibrogenic activity by measuring collagen secretion, alpha-SMA expression, and gel contraction capability. An animal study was conducted to confirm the fibrogenic activity of exosomes derived from arecoline-treated epithelial cells. Additionally, we employed a dipeptidyl peptidase-4 inhibitor to assess its efficacy in mitigating fibrogenesis. RESULTS: Following arecoline treatment, an increase dipeptidyl peptidase-4 expression was observed in exosomes from the treated epithelium cells. When these exosomes cocultured with fibroblast, fibrogenic gene alpha-SMA was upregulated, increased collagen secretion, and enhanced gel contraction capability. In a mouse model, the administration of arecoline-treated epithelium-derived exosomes induced oral submucous fibrosis phenotype, characterized by a reduction in incisal distance and epithelial atrophy. CONCLUSIONS: These findings offer valuable insights into clinical strategies for combating oral fibrotic disease and contribute to the foundation of future research in this field.