GM1 ganglioside modulates the inflammasome-autophagy axis to protect microglia against Aβ oligomer-induced neuroinflammation

Background : Lipid dysregulation contributes to Alzheimer's disease (AD) pathogenesis, yet the role of lipids in modulating microglial function remains poorly understood. Microglial activation by beta-amyloid (Aβ) involves the NLRP3 inflammasome, which drives pro-inflammatory cytokine release, and the autophagy-lysosome pathway, which degrades protein aggregates and regulates inflammatory resolution. GM1 ganglioside is the most abundant ganglioside in the adult human brain and exhibits neuroprotective effects; however, the mechanisms by which GM1 influences these key microglial processes during Aβ processing are unclear. This study investigates how GM1 ganglioside regulates microglial activation induced by Aβ oligomers (AβO). Methods : We performed in vitro studies using BV-2 and primary microglia cultures. Microglial ganglioside levels were modulated by administering exogenous GM1 for 2 hours prior to AβO exposure. Ganglioside content was quantified using ESI-mass spectrometry, and ganglioside metabolism was assessed through mass spectrometry analysis and transcription of catabolic enzymes. NLRP3 inflammasome priming and activation were evaluated by measuring pro-inflammatory cytokine transcription and secretion, respectively. Autophagy and lysosome function were assessed using immunofluorescence and western blot analysis. Results : AβO at 1 µM concentration induced pro-inflammatory activation of BV-2 microglia and triggered NLRP3 inflammasome priming. AβO exposure upregulated ganglioside catabolism while preserving GM1 levels through complex ganglioside degradation. GM1-enriched microglia exhibited a suppressed inflammatory response to AβO, characterized by attenuated NLRP3 inflammasome priming and reduced IL-1β secretion. Additionally, GM1 enrichment enhanced autophagy flux in AβO-activated microglia by modulating the mTOR signaling pathway and promoted inflammatory resolution through lysosomal degradation of NLRP3. Conclusion : This work identifies a novel immunomodulatory mechanism by which GM1 ganglioside regulates key microglial functions essential for Aβ processing. GM1 provides dual protection against neuroinflammation by attenuating inflammasome priming and enhancing autophagy-mediated inflammatory resolution, demonstrating the therapeutic potential of targeting ganglioside metabolism to alleviate neuroinflammation in AD.