Influence of MPO/NLRP3 Axis-Mediated Neutrophil Extracellular Traps on Diabetic Neuropathic Pain in a Mouse Model.

BACKGROUND

Diabetic peripheral neuropathy (DPN) is a debilitating diabetic complication with progressive nerve damage and chronic pain. The limited efficacy of current treatments reflects the incomplete understanding of its underlying mechanisms, particularly the role of neutrophil extracellular traps (NETs) in neuroinflammation.

METHODS

Using a streptozotocin (STZ)-induced DPN mouse model, we conducted quantitative proteomic analysis with functional validation. Pharmacological inhibition of protein-arginine deiminase type-4 (PAD4)-mediated NETs formation was achieved using Cl-amidine. Protein interaction networks were constructed via STRING and experimentally validated for key inflammatory pathways.

RESULTS

Proteomic analysis revealed a significant upregulation of myeloperoxidase (MPO) in DPN mice (45.0 ± 1.41 vs 28.3 ± 3.47; P = .002), with enrichment analysis indicating a strong association with the NETs pathway (fold enrichment = 5.03; P = .021). Functional assays showed that Cl-amidine significantly attenuated pain hypersensitivity over time, with repeated measures analysis of variance (ANOVA) confirming a significant group × time interaction ( P < .001). Post hoc analysis demonstrated increased paw withdrawal threshold (PWT: 0.450 ± 0.170 g vs 0.230 ± 0.170 g, P = .011) and hot withdrawal latency (HWT: 16.5 ± 3.76 seconds vs 11.4 ± 3.76 seconds; P = .002) at week 3. Cl-amidine also markedly reduced the expression of NETs-related proteins and proinflammatory cytokines. Protein-protein interaction (PPI) analysis detected MPO-NLR family pyrin domain containing 3 (NLRP3) association (textmining: 0.465) with ancillary co-expression support (0.042), consistent with their shared roles in inflammatory pathways. Notably, Cl-amidine treatment significantly decreased NLRP3-related proteins along with interleukin (IL)-1β and IL-18 levels.

CONCLUSIONS

This study is the first to reveal that the MPO/NLRP3 axis mediates NETs-driven neuroinflammation in DPN. The findings provide molecular insights into DPN pathogenesis and suggest combined NETs clearance with inflammasome inhibition as a potential therapeutic strategy.