High-fructose diet induces depressive-like behaviors and short-term memory deficits through hippocampal neurogenesis impairment via neural stem cell dysfunction.

BACKGROUND: Neural stem cells (NSCs), crucial for brain function and repair, are disrupted by high-fructose diet (HFrD) in proliferation and survival, linking to neurogenesis impairment and neuropsychiatric risks. Mechanistic insights remain undefined. METHODS: Comprehensive behavioral assessments were conducted on HFrD mice, including the tail suspension test (TST) and sucrose preference test (SPT) for depressive-like behaviors, elevated plus maze (EPM) and open field test (OFT) for anxiety-like behaviors, as well as novel object recognition (NOR) and Morris water maze (MWM) for cognition. Hippocampal NSCs and newborn neurons were quantified by immunofluorescence, and fructose-treated NE-4C cells underwent RNA sequencing (RNA-seq) analysis coupled with measurements of proliferation, apoptosis and ferroptosis markers. RESULTS: HFrD mice showed depressive-like behaviors without anxiety-like behaviors, and exhibited impaired short-term memory in NOR but did not show impaired spatial memory in MWM. Decreased number of hippocampal NSCs and newborn neurons were observed, suggesting impaired neurogenesis. In vitro, fructose-treated NE-4c exhibited altered gene expression profiles, with PCA showing distinct clustering between treated and control groups. Further analysis (GO, KEGG, GSEA) indicated enrichment in energy metabolism pathways, including mitochondrial ATP synthesis (e.g., downregulated ATP5E, ATP5H). Consistently, intracellular ATP levels were elevated, indicating metabolic dysregulation. Further experiments demonstrated that high fructose promoted NSC proliferation via p53/Wnt pathways (upregulated CyclinA2, CDK1) while concurrently inducing apoptosis (BAX, P53 upregulation) and ferroptosis (reduced GPX4, elevated ROS, and lipid peroxidation). CONCLUSION: This study elucidates the mechanistic link between HFrD-induced metabolic disruption and NSC dysfunction, providing novel insights into the pathogenesis of fructose-associated neuropsychiatric disorders.