SPATIOTEMPORAL ACTIVATION OF NLRP3-MEDIATED PYROPTOSIS IN HIPPOCAMPAL SUBREGIONS OF 3XTG-AD MICE

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by chronic neuroinflammation and selective neuronal vulnerability. Increasing evidence implicates inflammasome-driven pyroptosis as a critical mechanism linking innate immune activation to neurodegeneration, mediated by the NLRP3-Caspase-1-Gasdermin D (GSDMD) axis. However, its regional and temporal dynamics within hippocampal subfields during AD progression remain poorly defined. This study mapped the spatiotemporal expression of pyroptosis-related markers across hippocampal subregions in the 3xTg-AD mouse model to identify early therapeutic windows. Hippocampal sections from 3xTg-AD and control mice at 3, 6, 12, and 16 months of age were analyzed by immunofluorescence for NLRP3, cleaved Caspase-1, GSDMD, NeuN, and Aβ1-42. Quantitative analyses targeted the subiculum, CA1, CA2, and CA3. Early upregulation of NLRP3 and GSDMD was observed in the subiculum and CA3 of 3xTg-AD mice, peaking at 6 months. This was followed by a selective reduction in cleaved Caspase-1-positive neurons in the subiculum at later stages, consistent with pyroptosis-associated neuronal loss. CA1 and CA2 showed minimal activation, indicating differential vulnerability. Transient increases in neuronal marker density in CA3 at early stages likely reflect inflammation-driven remodeling. Pyroptosis markers colocalized with amyloid plaques and hippocampal blood vessels in only 3xTg-AD mice, suggesting interactions among inflammasome activation, amyloid pathology, and neurovascular alterations. These findings reveal region-specific and sequential activation of NLRP3-mediated pyroptosis in the hippocampus during AD progression. The early inflammatory window before overt neuronal loss highlights pyroptosis as a key driver of selective vulnerability and supports early inflammasome-targeted interventions as a disease-modifying strategy in AD.