NLRC5-Mediated Epigenetic and Proteomic Regulation of Microglial Panoptosis Drives Neuroinflammation in Multiple Sclerosis

Background: Microglial dysfunction contributes to multiple sclerosis (MS) pathogenesis, yet the link between epigenetic regulation and inflammatory cell death (PANoptosis) remains unclear. This study explores NOD-like receptor family CARD domain containing 5 (NLRC5) as a regulator of microglial PANoptosis in MS. Methods: Transcriptomic data from experimental autoimmune encephalomyelitis (EAE) microglia (GSE253318) and GEO datasets (GSE78809, GSE154228) were integrated to identify panoptosis-related genes. Mendelian randomization (MR) linked NLRC5 expression to proteomic targets using UK Biobank and deCODE Iceland protein quantitative trait loci (pQTLs). Methylation quantitative trait locus (mQTL) analysis assessed MS-associated CpG sites. Lipopolysaccharide (LPS)-treated BV2 microglial models were used to validate NLRC5–PANoptosome assembly via Western blot and immunofluorescence. Results: NLRC5 was identified as a hub gene in PANoptosis-related pathways. MR revealed causal links between NLRC5 and apoptotic (GABA Type A Receptor-Associated Protein (GABARAP), BR Serine/Threonine Kinase 2 (BRSK2), TNF Superfamily Member 12 (TNFSF12)) and necroptotic (BCL2) effectors, consistent across inverse-variance weighted (iVW), Bayesian Weighted Mendelian Randomization (BWMR), and Generalized Summary-data-based Mendelian Randomization (GSMR) methods. Hypermethylation of NLRC5 (cg04097610) was associated with reduced MS risk (Odds Ratio (OR) = 0.885, p = 0.039). LPS stimulation upregulated NLRC5, Z-DNA binding protein 1 (ZBP1), apoptosis-associated speck-like protein containing a CARD (ASC), and cysteine-aspartic acid protease 8 (caspase-8), supporting PANoptosome activation. Conclusions: NLRC5 regulates microglial PANoptosis via epigenetic and proteomic mechanisms, linking inflammatory cell death to MS progression. These findings highlight NLRC5 as a potential therapeutic target in MS.