Ti(3)C(2)Tx MXene Potentiates PSAT1-Mediated Osteogenesis Through miR-665/GSK-3β/β-Catenin Axis to Counteract Inflammation-Induced Bone Loss.

INTRODUCTION: Inflammatory signaling-induced stem cell dysfunction severely impairs bone regeneration. This study aimed to develop a combinatorial strategy using Ti(3)C(2)T(x) MXene scaffolds and PSAT1-engineered dental pulp stem cells (oe-PSAT1 DPSCs) to counteract inflammation-mediated osteogenic suppression. METHODS: Dental pulp stem cells (DPSCs) were treated with TNF-α to simulate an inflammatory microenvironment. miR-665 expression and its targeting relationship with PSAT1 were analyzed via qRT-PCR, dual-luciferase reporter assay, and Western blot. The role of the miR-665/PSAT1/GSK-3β/β-catenin axis in osteogenic differentiation was evaluated using ALP activity, alizarin red staining, and immunofluorescence. Ti(3)C(2)T(x) MXene was synthesized and characterized, and its effects on ROS scavenging and osteogenesis were assessed in vitro. In vivo efficacy was validated using a rat calvarial defect model with micro-CT, histological staining, and immunohistochemistry. RESULTS: TNF-α stimulation upregulated miR-665, which directly targeted PSAT1 and inhibited the GSK-3β/β-catenin pathway, suppressing DPSCs osteogenic differentiation. PSAT1 overexpression rescued this suppression. Ti(3)C(2)T(x) MXene scavenged ROS, enhanced calcium-dependent mineralization, and synergized with oe-PSAT1 DPSCs to amplify β-catenin activation. In rat models, the Ti(3)C(2)T(x) MXene /oe-PSAT1 DPSCs combination achieved superior bone defect closure (higher BV/TV, Tb. Th, and mature collagen deposition) compared to Ti(3)C(2)T(x) MXene alone. DISCUSSION: This study identifies the miR-665/PSAT1/GSK-3β/β-catenin axis as a key regulator of inflammatory osteogenesis. The Ti(3)C(2)T(x) MXene/oe-PSAT1 DPSCs strategy concurrently neutralizes oxidative stress and activates osteogenic signaling, providing a translatable platform for inflammatory bone regeneration.