Single-cell atlas of transcriptomic vulnerability across brain disorders

A central goal of the study was to identify shared molecular mechanisms across diverse brain disorders. The authors found that interindividual variation accounts for approximately 7.5% of total gene expression variation, while cell type identity explains over 50%. By comparing transcriptomic signatures across diseases, the researchers identified universal pathways—such as mRNA processing and protein localization—that are perturbed across multiple conditions. Notably, they observed that diseases with higher genetic co-heritability, such as AD and diffuse Lewy body disease (DLBD), exhibit greater transcriptomic concordance, suggesting that shared genetic risk factors drive convergent molecular dysregulation.

The study provides a granular look at the progression of AD. Using neural network models, the authors constructed cell-type-specific disease trajectories based on tau pathology and cognitive decline. They identified a nonlinear transition between early and late disease stages, characterized by distinct cellular responses. Early stages involve innate immune activation and metabolic shifts in neurons, while late stages are marked by adaptive immune responses and vascular dysfunction. Mediation analysis suggests that microglia and vascular leptomeningeal cells (VLMCs) play critical roles in the causal cascade leading to dementia, while specific inhibitory neuronal subtypes, such as SST+ interneurons, may exert protective effects against amyloid plaque accumulation.

This atlas provides a foundational resource for understanding the molecular landscape of brain disorders. By distinguishing between shared pathogenic mechanisms and disease-specific signatures, the findings offer potential targets for therapeutic intervention. The identification of cell types that serve as hubs for genetic risk convergence, such as deep-layer excitatory neurons and Chandelier cells, highlights new priorities for mechanistic research into neurodegeneration and neuropsychiatric illness.