Gingiva-Derived Decellularised Extracellular Matrix Hydrogel Supports Osteogenic and Angiogenic Phenotypes of 3D STRO-1+ GMSC/HUVEC Spheroids In Vitro

Introduction and aims: Stem cell-based bone tissue engineering is often limited by insufficient osteogenic differentiation and inadequate vascularisation, largely attributable to the absence of a biomimetic stem cell niche. This study aimed to develop a human gingiva-derived decellularised extracellular matrix hydrogel (G-dECM) as a supportive microenvironment for three-dimensional (3D) coculture spheroids of STRO-1⁺ gingival mesenchymal stem cells (sGMSC) and human umbilical vein endothelial cells (HUVEC), thereby promoting the expression of osteogenic and angiogenic markers. Methods: Human gingival tissue was processed through decellularisation, enzymatic digestion, and sol-gel transformation to prepare G-dECM hydrogel. Composite 3D sGMSC/HUVEC spheroids (GHS) were generated and encapsulated within G-dECM. Morphological assessment, viability evaluation, and osteogenic differentiation analyses were conducted. Transcriptomic profiling was performed to identify G-dECM-associated regulatory signalling pathways. Results: G-dECM exhibited a porous, collagen-rich structure enriched with bioactive ECM proteins. Encapsulation of GHS within G-dECM enhanced cellular viability, promoted the expression of osteogenic and angiogenic markers, and improved spheroid structural integrity compared with matrix-free controls. Transcriptomic analysis revealed activation of TGF-β/SMAD and BMP signalling pathways associated with osteogenic differentiation. Conclusion: G-dECM provides a biomimetic stem cell niche that supports the osteogenic and angiogenic phenotypes of 3D sGMSC/HUVEC spheroids, establishing an integrated regenerative graft system combining seed cells, scaffold, and endogenous signalling cues. Clinical relevance: This G-dECM-based composite graft strategy offers a promising translational approach for the regeneration of alveolar bone defects associated with periodontal disease, trauma, or tooth extraction.