Exosomes derived from bone substitute-induced gingival mesenchymal stem cells promote angiogenesis

In certain clinical bone grafting scenarios, bone substitutes frequently interface with the adjacent soft tissues. This study aimed to investigate whether deproteinized bovine bone mineral (DBBM) and coralline hydroxyapatite (CHA) induce paracrine responses in human gingival mesenchymal stem cells (GMSCs), thereby altering the pro-angiogenic capacity of their derived exosomes, and to profile specific cargo alterations.

Exosomes were isolated from GMSCs co-cultured with DBBM (DBBM-GEXO) or CHA (CHA-G-EXO), while native GMSCs-derived exosomes (G-EXO) were collected as controls. The angiogenic effects of these exosomes on human umbilical vein endothelial cells (HUVEC) were evaluated via cell proliferation, scratch wound healing, Western blot analysis, and Matrigel tube formation assays. Alterations in exosomal cargoes were profiled using data-independent acquisition (DIA) proteomics. The core identified exosomal protein was subsequently validated through specific antibody blockade.

Both bone substitutes supported robust GMSC attachment. Compared with native exosomes, DBBM-G-EXO and CHA-G-EXO significantly enhanced HUVEC proliferation, migration, and capillary-like network formation, while upregulating angiogenic markers. Proteomic analysis identified 206 commonly upregulated proteins in bone substitute-induced exosomes, showing significant enrichment in the "Angiogenesis" Gene Ontology (GO) term. Integrin beta-1 (ITGB1) occupied the central position in the protein network, aligning with its transcriptional upregulation in the induced GMSCs. Specific blockade of exosomal ITGB1 effectively abrogated the enhanced pro-angiogenic effects initially induced by the bone substitutes.

DBBM and CHA induce the paracrine reprogramming of GMSCs, significantly enhancing the effects of GMSCs-derived exosomes in promoting angiogenesis via ITGB1 enrichment.