A multi-Omic framework reveals cell-type-specific mechanisms of isofraxidin action in Alzheimer disease.

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder characterized by coordinated dysfunction across multiple brain cell types. Natural compounds with multi-target regulatory potential represent promising therapeutic candidates, yet their cell-type-specific mechanisms in the human AD brain remain incompletely understood. In this study, we integrated ligand-based target prediction with large-scale single-nucleus RNA sequencing (snRNA-seq) data from 201,074 nuclei obtained from AD and control human brain samples, together with subcluster-level functional profiling, cell-cell communication analysis, transcriptional regulatory network inference, and structure-based molecular docking and molecular dynamics simulations to systematically characterize the multicellular actions of isofraxidin. Our analyses identified 19 high-confidence isofraxidin targets exhibiting distinct enrichment patterns across AD-associated cell populations. Key targets-including ALOX5 in microglia, MAOB in astrocytes, HSPA1A in endothelial cells (EC), and CBR1 in oligodendrocytes (ODC)-were preferentially localized to disease-relevant cellular subclusters. snRNA-seq revealed marked remodeling of these cell types in AD, characterized by inflammatory microglia, reactive astrocytes, stress-impaired ECs and neurodegeneration-associated ODCs, which overlapped with the highest target enrichment. Functional and regulatory analyses indicated that these vulnerable states converge on oxidative stress, metabolic dysregulation, proteostasis impairment, and aberrant inflammatory signaling. Molecular docking and 100-ns molecular dynamics simulations further confirmed stable and energetically favorable binding of isofraxidin to its core targets. Collectively, this integrative single-cell framework delineates the cell-type-specific therapeutic landscape of isofraxidin in AD and highlights its potential to coordinately modulate key pathogenic pathways underlying neurodegeneration.