Alpha protein kinase 1 knockout mitigates microglial pyroptosis and cognition deficits in ADP-heptose-stimulated mice

Abstract

Microglial activation and pyroptosis are central to neuroinflammation and significantly contribute to cognitive decline associated with neurodegenerative diseases. Alpha protein kinase 1 (ALPK1) is recently identified as a critical mediator of inflammatory responses in response to ADP-heptose (a pathogen-associated molecular pattern). However, its specific role in microglial pyroptosis and cognitive dysfunction remains unclear. In this study, we investigated the effects of ALPK1 on cognitive function and pyroptosis in wild-type (WT) and ALPK1 KO mice by intracerebroventricular administration of ADP-heptose to induce neuroinflammation. Cognitive performance was evaluated using behavioral tests (the Y-Maze, Morris Water Maze, and step-down passive avoidance), while Western blot, immunofluorescence, transmission electron microscopy, and enzyme-linked immunosorbent assay were used to evaluate the expression of pyroptosis markers such as NLRP3, Caspase-1, and gasdermin D (GSDMD) in vivo and in vitro. Our results reveal that the absence of ALPK1 significantly attenuated ADP-heptose-induced cognitive deficits and neuronal injury, and inhibited the NLRP3/Caspase-1/GSDMD pathway of pyroptosis and the secretion of pro-inflammatory cytokines IL-1β and IL-18. Notably, ADP-heptose-stimulated conditioned media from primary microglial cells of ALPK1 KO mice significantly enhanced neuronal cell viability, suggesting a protective role for ALPK1 deficiency in supporting neuronal health. These findings suggest the pivotal role of ALPK1 in ADP-heptose-induced microglial pyroptosis and cognitive impairment, thereby highlighting its potential as a therapeutic target in neuroinflammatory disorders.