Introduction/Rationale: NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation has been implicated in neurodegenerative diseases. Despite this association, how inflammasome activation drives central nervous system (CNS) dysfunction is poorly understood. To explore this, we used humanized NLRP3 D305N gain-of-function (GoF) mice, which exhibit constitutive inflammasome activation and systemic inflammation.
Methods: Here, we investigated the effects of chronic NLRP3 activation on CNS immunity using D305N mice. These mice exhibited age-dependent neurodegeneration, indicated by elevated neurofilament light chain (NfL), and displayed marked accumulation of immune cells, specifically neutrophils, monocytes, and T cells, within the leptomeninges. Immunohistochemistry showed that neutrophils uniquely exhibited robust extravasation into the adjacent parenchyma.
Results: Single-cell RNA sequencing (scRNA-seq) of neutrophils demonstrated increased abundance and terminal differentiation in D305N mice. In parallel, multimodal analyses—including imaging, scRNA-seq, and spatial transcriptomics—showed that microglia underwent transcriptomic and morphological reprogramming toward a reactive phenotype, with evidence of close interaction with infiltrating neutrophils.
Conclusion: Collectively, these findings reveal that chronic NLRP3 GoF activity drives aberrant microglial activation and promotes peripheral immune infiltration into the CNS, with neutrophils as key contributors to neuroinflammatory pathology.
