Transcriptomic Analysis of the Human Habenula in Schizophrenia

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• The human habenula (Hb) is implicated in neuropsychiatric disorders.
• Its molecular neuroanatomy and transcriptomic landscape in schizophrenia remain largely undefined.

Purpose of the Study:

• To define the molecular neuroanatomy of the human habenula.
• To identify transcriptomic differences in the habenula between schizophrenia and control brains.

Main Methods:

• Single-nucleus RNA sequencing (snRNA-seq) to identify Hb cell types.
• Single-molecule fluorescent in situ hybridization (smFISH) for spatial validation.
• Bulk RNA sequencing (RNA-seq) and cell type deconvolution to find differentially expressed genes (DEGs) in schizophrenia.

Main Results:

• Identified 17 distinct Hb cell type clusters, including medial and lateral populations.
• Discovered 173 schizophrenia-associated DEGs in Hb-enriched tissue, with 75% unique to the habenula.
• Found 16 colocalized genes between eQTLs and schizophrenia risk variants, nine novel.

Conclusions:

• The human habenula exhibits topographically organized cell types with unique molecular signatures.
• Schizophrenia is associated with distinct genetic differences in the habenula.
• These findings provide novel molecular insights into the habenula's role in neuropsychiatric disorders.