Background: Alzheimer’s disease (AD) involves a progressive deterioration of cognitive abilities, memory loss, and persistent brain inflammation. Emerging evidence indicates that pyroptosis mediated by the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, contributes significantly to AD development. Docosahexaenoic acid (DHA) has demonstrated neuroprotective properties; however, the precise mechanisms by which it modulates pyroptosis in AD have yet to remained incompletely elucidated. Objective: To explore the role of DHA in modulating microglial pyroptosis via the HOXA9-NLRP3 pathway in an AD model. Methods: Effects of DHA on Aβ25–35-induced pyroptosis were assessed in human microglial clone 3 (HMC3) human microglial cells using CCK-8, western blotting, immunofluorescence, and Enzyme-linked Immunosorbent Assay (ELISA) assays. The role of homeobox A9 (HOXA9) in pyroptosis regulation was evaluated through overexpression and knockdown experiments. Dual-luciferase reporter assays together with chromatin immunoprecipitation (ChIP) were used to verify the interaction of HOXA9 to NLRP3 promoter. Amyloid precursor protein / Presenilin-1 double-transgenic (APP/PS1) transgenic AD mice underwent DHA treatment in vivo, and cognitive performance was assessed using the Morris water maze paradigm. Expression of HOXA9, NLRP3, and pyroptosis-related proteins were analyzed by Quantitative Real-time Reverse Transcription PCR (qRT-PCR), Western blotting, and immunofluorescence. Results: DHA treatment significantly reduced Aβ25–35-induced microglial pyroptosis, as indicated by decreased levels of p30-Gasdermin D (GSDMD), cleaved-caspase-1, IL-1β, and IL-18. HOXA9 overexpression reversed the protective effects of DHA, whereas NLRP3 inhibition by MCC950 enhanced DHA inhibition of pyroptosis. Dual-luciferase and ChIP assays confirmed that HOXA9 directly regulates NLRP3 transcription. In APP/PS1 mice, DHA administration enhanced cognitive performance while simultaneously decreasing the expression of pyroptosis-related markers and inflammatory mediators in brain. Inhibition of NLRP3 signaling by MCC950 further strengthened the neuroprotective actions of DHA. Conclusion: DHA ameliorates AD-related cognitive decline and reduces microglial pyroptosis through suppressing the HOXA9-NLRP3 axis. These results offer novel insights into the molecular basis of DHA-mediated neuroprotection and highlight potential therapeutic targets for AD.
Xie et al. (Sat,) studied this question.