Background: Alzheimer's disease (AD) is a severe neurodegenerative disorder that progressively destroys cognitive skills. Exploring the mechanism underlying autophagic clearance of phosphorylated tau (p-Tau) contributes to developing novel therapeutic strategies for AD.
Methods: SH-SY5Y and HT22 cells were treated with Aβ1-42 to establish an in vitro model of AD. Cell viability was examined using CCK-8. TUNEL staining was applied to evaluate cell apoptosis. LC3 puncta was examined by IF staining. m6A modification level was evaluated through MeRIP. RNA pull-down and RIP assays were used for analyzing the interaction between IGF2BP1 and STUB1 transcripts. The binding of KDM1A to the promoter of METTL3 was confirmed by ChIP assays. APP/PS1 transgenic mice were used as an in vivo model of AD. Cognitive skills of mice were evaluated with the Morris water maze. Hippocampal damage and Aβ deposition were detected through H&E and IHC staining.
Results: Dysregulated levels of autophagy, p-Tau and m6A was observed in an in vitro model of AD. Overexpression of METTL3 or STUB1 enhanced autophagy but reduced p-Tau level in Aβ1-42-treated cells. METTL3 stabilized STUB1 mRNA through the m6A-IGF2BP1-dependent mechanism and naturally promoted STUB1 expression, thereby enhancing autophagic p-Tau clearance in Aβ1-42-treated cells. Overexpression of KDM1A enhanced autophagy, m6A modification and autophagic p-Tau clearance in Aβ1-42-treated cells. KDM1A-mediated upregulation of METTL3 promoted autophagic p-Tau clearance and ameliorated Alzheimer's disease both in vitro and in vivo.
Conclusion: KDM1A-mediated upregulation of METTL3 enhances autophagic clearance of p-Tau through m6A-dependent regulation of STUB1, thus ameliorating Alzheimer's disease. Our study provides novel mechanistic insights into AD pathogenesis and potential drug targets for AD.
Keywords: Alzheimer's disease; Autophagic p-Tau clearance; KDM1A; METTL3; STUB1; m6A modification.
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