Drynaria roosii-derived exosome-like nanovesicles promote alveolar socket healing via activation of ITPR3-mediated calcium flux.

Alveolar socket healing post-extraction is accompanied by alveolar bone loss, which is negative to subsequent prosthetic rehabilitation. Plant-derived exosome-like nanovesicles are extracellular vehicles with great potential for disease treatment and are advantageous for drug delivery and absorption. Herein, we report the mineralization-promoting effects of Drynaria roosii-derived exosome-like nanovesicles (DRDENs) on osteoblasts and in a mouse alveolar socket healing model. DRDENs were isolated and characterized. Treatment with DRDENs increased the formation of calcium nodules and the expression of osteogenic differentiation markers (ALP, RUNX2, and OCN) in osteoblasts. Compounds analysis of DRDENs revealed a previously unexplored component, naringenin chalcone. We evaluated the properties of naringenin chalcone and its bioactivity on osteoblast differentiation. In vivo studies confirmed the safety and efficacy of DRDENs and naringenin chalcone in bone regeneration. The mechanism was demonstrated in which DRDENs were endocytosed by cells, and naringenin chalcone was released to interact with the inositol 1,4,5-trisphosphate receptor type 3 (ITPR3) in the endoplasmic reticulum (ER), thereby activating downstream calcium flux to enhance bone formation. Additionally, chalcone isomerase (CHI), a key enzyme involved in naringenin chalcone production in Drynaria roosii, was purified and functionally identified as a type I CHI with weak II CHI activity. Our findings provided a novel strategy for alveolar socket healing and shed light on the function of CHI in Drynaria roosii.