6th Edition of Neurology World Conference 2026

Abstract

Background: Multiple sclerosis (MS) is an autoimmune disease characterized by persistent central nervous system inflammation, demyelination, and progressive neurodegeneration. Current disease-modifying therapies have limited efficacy against compartmentalized meningeal inflammation. The contribution of phenotypically distinct dura-associated macrophages to this process remains poorly understood. Aim: This study investigated whether nuclear factor, interleukin 3 regulated (NFIL3) controls the pathogenic activity of CD300 molecule-like family member F (CD300LF)-positive dura-associated macrophages by transcriptionally regulating vascular endothelial growth factor A (VEGFA), and whether this pathway contributes to blood-brain barrier dysfunction and central immune-cell accumulation. Materials and Methods: Experimental autoimmune encephalomyelitis was induced in mice as a model of MS. Dural immune populations were characterized using single-cell ribonucleic acid sequencing, flow cytometry, and immunofluorescence staining. Bioinformatic transcription-factor analysis and functional NFIL3 perturbation were combined with dual-luciferase reporter assays and chromatin immunoprecipitation followed by quantitative polymerase chain reaction to determine whether NFIL3 directly regulates VEGFA transcription. Clodronate liposomes were administered by subdural injection to deplete meningeal macrophages, while a VEGFA inhibitor was delivered through the same route to examine the contribution of local VEGFA signaling. CD300LF-positive macrophage abundance, blood-brain barrier integrity, central T-cell accumulation, and neurological disability were evaluated. Results: A distinct CD300LF-positive dura-associated macrophage population was markedly enriched during disease progression. Dual-luciferase reporter assays demonstrated NFIL3-dependent VEGFA promoter activation, while chromatin immunoprecipitation followed by quantitative polymerase chain reaction confirmed NFIL3 enrichment at VEGFA regulatory regions, supporting direct transcriptional control. CD300LF-positive macrophages displayed enhanced VEGFA production, which was associated with blood-brain barrier disruption and increased T-cell accumulation in the central nervous system, consistent with a potential downstream effect on cerebrovascular endothelial cells. Subdural clodronate liposomes reduced CD300LF-positive macrophages and alleviated motor impairment in experimental autoimmune encephalomyelitis mice. Local VEGFA inhibition similarly reduced CD300LF-positive macrophage accumulation, as confirmed by flow cytometry and immunofluorescence staining, and improved neurological function. Conclusion: NFIL3 transcriptionally activates VEGFA in CD300LF-positive dura-associated macrophages, thereby promoting a pathogenic meningeal immune response in MS. Macrophage-derived VEGFA may exacerbate neuroinflammation by acting on cerebrovascular endothelial cells, impairing blood-brain barrier integrity, and facilitating central T-cell accumulation. The NFIL3-CD300LF-positive macrophage-VEGFA axis represents a potential therapeutic target for progressive MS.