Keratinocyte Autophagy-Mediated Self-Assembling Tetrahedral Framework Nucleic Acid Induces Wound Healing and Reduces Scar Hyperplasia

Tetrahedral framework nucleic acid (tFNA) efficiently treats various diseases; however, its effect on wound healing is unknown. We investigated tFNA's impact on human immortalized epidermal cells (HaCaT) cells and wound healing through in vitro and in vivo experiments. The tFNA is taken up by cells and exhibits good biocompatibility. Transmission electron microscopy and autophagic flux assays showed that tFNA substantially increased the number of intracellular autophagosomes, thus suggesting the activation of cell autophagy. Immunofluorescence and western blotting results indicated decreased microtubule-associated protein 1 light chain 3I (LC 3I) and prostacyclin (P62) levels, and increased microtubule-associated protein 1 light chain 3II (LC 3II), suggesting increased autophagic activity. Adenosine 5′-monophosphate-activated protein kinase (AMPK) and unc-51-like kinase 1 (ULK1) activation, and mechanistic target of rapamycin (mTOR) inhibition were also observed, suggesting their involvement in tFNA-induced cell activation. Autophagy-related protein (ATG) 5 and ATG7 knockdown in HaCaT cells reverse confirmed these results. Animal experiment results mirrored the cellular findings, revealing autophagy induction, wound healing promotion, and effective scar score reduction. These results suggest that tFNA promotes HaCaT cell autophagy activation through mTOR pathway inhibition, promoting wound healing and reducing scarring. Our findings expand the application of tFNA and highlight new avenues for clinical wound treatment.