Hongwei Qin | Single cell mapping of neutrophil diversity in

Hongwei Qin, University of Alabama at Birmingham, USA Title: Single cell mapping of neutrophil diversity in neuroinflammation Abstract: Multiple sclerosis (MS) is an autoimmune demyelinating disease of the central nervous system (CNS) characterized by multifocal inflammation and axonal degeneration driven by immune cells. The JAK/ STAT pathway regulates immune cell activation, with Suppressors Of Cytokine Signaling (SOCS) proteins functioning as negative regulators. Using the model of MS, Experimental Autoimmune Encephalomyelitis (EAE), we had demonstrated that mice lacking Socs3 in myeloid cells developed severe, brain-targeted EAE (btEAE), with increased cerebellar infiltration of activated neutrophils. To define neutrophil-specific roles of Socs3, we generated mice with Socs3 deletion in neutrophils (Socs3ΔLy6G). Following EAE, Socs3ΔLy6G mice exhibited severe cerebellar demyelination, increased cerebellar infiltration of activated neutrophils and CD4+ T-cells, and clinical symptoms of both btEAE and classical EAE (cEAE). Cerebellar neutrophils from Socs3ΔLy6G mice exhibited a primed, inflammatory phenotype with elevated reactive oxygen species, neutrophil extracellular traps (NETs) and heightened production of pro-inflammatory cytokines/chemokines. Single-cell RNA Sequencing (scRNA-Seq) of cerebellum (CB) and spinal cord (SC) revealed five neutrophil clusters in naïve and EAE mice, with expansion of Neu2 and Neu4 clusters in Socs3ΔLy6G EAE mice. Neu2, Neu3 and Neu4 clusters showed high expression of Saa3, Il1b and Cxcl2. Neu4 specifically enriched in cytokine signaling pathways and inflammatory responses. Strikingly, Saa3 mRNA and protein expression were markedly increased in the CB and SC of Socs3ΔLy6G EAE mice compared to controls. Translationally, the human orthologue SAA1 was significantly elevated in plasma from MS patients relative to healthy controls. Collectively, our findings demonstrate that Socs3 deficiency unleashes pathogenic neutrophil activity in Socs3ΔLy6G EAE mice. We further demonstrate neutrophil heterogeneity and define inflammatory transcriptional states linked to Saa3/SAA1, suggesting these signatures may serve as biomarkers or therapeutic targets in neuroinflammatory disorders, including Alzheimer’s Disease. #ISAD2026 #Alzheimers #Dementia #AlzheimersDisease #DementiaResearch #AlzheimersResearch #Neuroscience #NeurodegenerativeDiseases #BrainHealth #Neuroinflammation #Amyloid #TauProtein #Biomarkers #ClinicalResearch #ScientificConference #MedicalConference #InternationalConference #ResearchCollaboration #Innovinc #InnovincConferences #InnovincInternational #ParisConference