The miR-335-5p/DKK1/autophagy axis regulates TNF-α-mediated dysfunction of dental pulp stem cells

Dental pulp stem cells (DPSCs) play a critical role in maintaining dental pulp homeostasis and supporting dentin-pulp complex regeneration, while tumor necrosis factor-α (TNF-α)-mediated inflammation severely impairs their biological functions. This study explored the role of the miR-335-5p/DKK1/autophagy axis in TNF-α-induced DPSCs dysfunction. Human DPSCs were stimulated with 20 ng/mL TNF-α; miR-335-5p overexpression and DKK1 silencing were achieved via transfection. qRT-PCR, Western blot, SA-β-gal staining, immunofluorescence, transmission electron microscopy, ALP/ARS staining, and dual-luciferase assay were used to detect related indicators. Results showed TNF-α downregulated miR-335-5p, upregulated DKK1, inhibited autophagy, induced senescence, disrupted cytoskeleton, and suppressed osteogenesis; miR-335-5p directly targeted DKK1's 3'-UTR. Overexpressing miR-335-5p or silencing DKK1 restored DPSCs' autophagic flux, alleviated senescence, and rescued osteogenic potential. In conclusion, the miR-335-5p/DKK1/autophagy axis mediates TNF-α-induced DPSCs dysfunction, and targeting this axis may improve stem cell-based dental pulp and bone reconstruction under inflammation.