Alzheimer's disease (AD), a prevalent neurodegenerative disorder, is primarily characterized by β-amyloid (Aβ) deposition. Current therapies alleviate symptoms but lack agents capable of modifying disease progression. Meanwhile, cross-regional studies indicate that AD patients exhibit disrupted gut microbiota composition, which is closely associated with cerebral molecular dysregulation. Building on this gut-brain connection, this study aimed to attenuate AD progression by targeting gut microbiota through microbially metabolized carbohydrates. Specifically, using 5 × FAD mice modeling AD pathology, we conducted 16S rRNA sequencing, targeted metabolomics of microbiota-derived metabolites, and bulk RNA sequencing experiments to investigate gut-brain axis alterations. Our results show that AD mice exhibited gut dysbiosis, depletion of short chain fatty acids (SCFAs), and transcriptomic dysregulation in the hippocampus, particularly affecting aging and synaptic plasticity-related genes. Dietary intervention with arabinoxylan significantly increased SCFAs-producing bacteria (Oscillospiraceae and Eubacterium_coprostanoligenes_group), elevated butyric acid, and thereby reversed expression levels of these aging and synaptic plasticity-related genes. Mechanistically, arabinoxylan alleviated AD-like symptoms by modulating the microbiota-gut-brain (MGB) axis; this beneficial effect occurred through enrichment of probiotic bacteria that produce SCFAs to regulate hippocampal synaptic plasticity genes. Collectively, this work proposes arabinoxylan as a novel prebiotic strategy and identifies candidate therapeutic targets for AD treatment.
