The interaction between FLOT1 and FOSL2 promotes EphA2 transcription, regulating microglial polarization and affecting neuroinflammation in Alzheimer's disease.

Abstract

BACKGROUND: Microglial activation plays a crucial role in Alzheimer's disease (AD), responding to amyloid-beta (Aβ) plaques and tau tangles. Initially protective, microglia clear Aβ deposits and support neuronal health, but later adopt a pro-inflammatory, neurotoxic state, releasing cytokines that exacerbate neuroinflammation and neuronal damage. Understanding the mechanisms driving this shift is essential for developing therapies to modulate microglial activation and slow AD progression. METHODS: Quantitative PCR (qPCR), Western blotting, immunohistochemistry (IHC), and immunofluorescence (IF) assays were performed to confirm gene and protein expression levels. Chromatin immunoprecipitation (ChIP), co-immunoprecipitation (CoIP), and dual-luciferase assays were conducted to assess the interactions among FLOT1, FOSL2, and EphA2. The Morris water maze test was used to evaluate spatial learning and memory, with experiments conducted using the APP/PS1 mouse model. RESULTS: In this study, we found that silencing of FLOT1 in APP/PS1 mice significantly reduced neuroinflammatory markers, prevented pro-inflammatory polarization, and improved spatial memory. Mechanistically, we observed that FLOT1 interacted with the transcription factor FOSL2, which upregulated EphA2 expression, leading to activation of the p38/MAPK signaling pathway. Disrupting EphA2 expression deactivated this pathway, reducing pro-inflammatory polarization in microglia. Our findings further confirmed that the FLOT1-FOSL2 axis regulated microglial polarization in vivo and that targeting this pathway improved cognitive outcomes in AD models. CONCLUSION: Overall, these results highlight the FLOT1-FOSL2-EphA2 pathway as a potential therapeutic target for AD, as modulating this axis may reduce neurotoxic inflammation and help preserve cognitive function.