Downregulation of miR-33a-5p regulates TNF-α/NF-κB signaling and is associated with reduced diabetic neuropathic pain through targeting SIRT6.

BACKGROUND: The pathogenesis of diabetic neuropathic pain (DNP) remains unclear, with neuroinflammation mediated by abnormal TNF-α/NF-κB pathway activation being a key factor. This study aims to elucidate how this pathway contributes to DNP. METHODS: miR-33a-5p levels were measured via qPCR in the serum of diabetic patients and in cell models. Its diagnostic value for DNP was assessed using ROC and logistic regression. A high-glucose HMC3 microglia model was established. TNF-α and NF-κB levels were quantified by ELISA. Cell proliferation and oxidative stress were evaluated. The targeting relationship between miR-33a-5p and SIRT6 was confirmed by dual-luciferase assay, and their regulatory effects on TNF-α and NF-κB expression were examined. RESULTS: miR-33a-5p was significantly elevated in DNP patients (p < 0.001) and correlated positively with HbA1c (p < 0.001), demonstrating strong diagnostic value (AUC = 0.906, p < 0.001). DNP was associated with higher miR-33a-5p expression, in addition to its association with HbA1c levels. In vitro, high glucose upregulated miR-33a-5p (p < 0.01), NF-κB (p < 0.001), and TNF-α (p < 0.001) in microglia. Mechanistically, miR-33a-5p targets SIRT6, activating the NF-κB/TNF-α/p38MAPK pathway and worsening oxidative stress (p < 0.001). Inhibiting miR-33a-5p or overexpressing SIRT6 alleviated microglial activation and inflammation (p < 0.01). CONCLUSION: miR-33a-5p aggravates DNP by regulating SIRT6 and enhancing TNF-α/NF-κB signaling; its inhibition may reduce neuroinflammation and pain.