RRx-001 ameliorates astrocyte pyroptosis by regulating LCN2-NLRP3 inflammasome activation in an MPTP-induced parkinson’s disease mouse model

Parkinson's disease (PD) is characterized by progressive neurodegeneration closely linked to neuroinflammation and oxidative stress-induced damage and is characterized by the loss of dopaminergic (DAergic) neurons and the inflammatory response associated with glial cells. RRx-001 (RRx, 2-bromo-1-(3,3-dinitroazetidin-1-yl)ethanone) is a small-molecule immunoregulator. Recent studies have shown that it strongly inhibits NLRP3 (NOD-like receptor family pyrin domain containing 3) inflammasome activation, which is crucial for influencing neuroinflammation. However, the mechanism underlying the effect of RRx on PD remains unclear. In this study, we explored the potential effects of RRX on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice, detected the transcriptome and metabolome of the substantia nigra, and performed 16 S microbial diversity sequencing and metabolomics of the intestinal tract. Our study revealed that RRx obviously relieves MPTP-induced DAergic neuronal loss and motor disorders. Mechanistically, RRx reversed the upregulated expression of lipocalin-2 (LCN2) and NLRP3 inflammasome activation in a PD model. Crucially, its protective effects on DAergic neurons involved improving LCN2-NLRP3 inflammasome activation-mediated astrocyte pyroptosis. RRx also reduced the levels of metabolites and signalling pathways associated with oxidative stress and PD in the substantia nigra. Furthermore, the 16 S rDNA analysis and metabolomic analysis of faecal pellets revealed that the intestinal tract of the RRx-treated PD mice presented a greater abundance of Deferribacterota at the phylum level than that of the PD model mice, and the gut microbiota metabolites and pathways were altered. Overall, the results of this study indicate that RRx has multiple effects on PD.