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This study applied single-nucleus RNA sequencing to postmortem ventral tegmental area (VTA) tissue from individuals with alcohol use disorder (AUD) and matched controls, identifying thousands of differentially expressed genes across six major cell types including neurons, astrocytes, microglia, and endothelial cells. Gene expression changes were enriched for pathways related to mitochondrial function, neurodegeneration, and synaptic signaling, with addiction- and synapse-related pathway alterations appearing specific to dopaminergic neurons. Further subdivision of mature neurons into dopaminergic, GABAergic, and glutamatergic subtypes revealed distinct transcriptomic profiles, suggesting cell type-specific molecular mechanisms contribute to AUD pathophysiology in the VTA.
Why it matters
Understanding which cell types and biological pathways are disrupted in the reward circuitry of individuals with AUD may help identify more precise molecular targets for pharmacological or therapeutic interventions. This work also establishes a foundational cell type-resolved reference for the human VTA that could inform future research on addiction and related neuropsychiatric conditions.
⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Background: Alcohol use disorder (AUD) is associated with altered gene expression across diverse cell types in reward-related brain regions, including the ventral tegmental area (VTA), which is rich in dopaminergic neurons. The VTA plays a central role in reward processing, learning, and memory; however, cell type-specific gene expression changes within the VTA remain uncharacterized. Methods: We applied single-nucleus RNA sequencing (snRNA-seq) to profile transcriptomic alterations associated with AUD in the VTA. Postmortem VTA samples from four individuals of European ancestry [two with AUD (one male, one female) and two matched controls (one male, one female)] were analyzed using the 10X Genomics Chromium Fixed RNA Profiling protocol. Differentially expressed genes (DEGs) were identified using Seurat, and enriched KEGG pathways was assessed by gene set enrichment analysis. Results: Nuclei were classified into six major cell types: astrocytes, endothelial cells, mature neurons, microglia, oligodendrocytes, and oligodendrocyte precursor cells (OPCs). At thresholds of P < 0.05 and |fold change| > 2.0, we identified 547 DEGs in astrocytes, 727 DEGs in endothelial cells, 715 DEGs in mature neurons, 421 DEGs in microglia, 263 DEGs in oligodendrocytes, and 432 DEGs in OPCs. DEGs across VTA cell types were enriched for pathways related to mitochondrial function, neurodegeneration, and synaptic signaling. Notably, DEGs in mature neurons were enriched for addiction-related pathways. Further subdivision of mature neurons into dopaminergic, GABAergic, glutamatergic, and unclassified subtypes revealed 526, 930, 896, and 569 DEGs, respectively. Neuronal DEGs indicate a convergence on mitochondrial/oxidative phosphorylation and neurodegeneration-related pathways across subtypes, whereas addiction- and synapse-related pathways show dopaminergic neuron-specific enrichment. Conclusions: This study provides the first cell type-resolved transcriptomic profiling of the human VTA, revealing AUD-associated gene expression alterations across neuronal, glial, and endothelial cells. The observed cell type-specific changes in synaptic plasticity and addiction-related genes offer new insights into molecular mechanisms underlying AUD pathophysiology.