Sex Differences in Brain Cell Type-Specific Chromatin Accessibility in Schizophrenia

Area of Science:

• Neuroscience
• Genomics
• Epigenetics

Background:

• The sex-specific role of the noncoding genome in serious mental illnesses like schizophrenia (SCZ) is not well understood.
• Existing research has not fully elucidated the epigenetic mechanisms underlying sex differences in SCZ.

Purpose of the Study:

• To investigate sex differences in chromatin accessibility and gene regulation in the brain.
• To identify sex-specific regulatory elements and their association with schizophrenia risk.

Main Methods:

• Analyzed 1393 chromatin accessibility profiles from neuronal and non-neuronal nuclei in two cortical regions.
• Examined individuals with serious mental illness and controls to identify sex-specific patterns.
• Utilized chromosomal conformation capture techniques to identify cis- and trans-regulatory domains.

Main Results:

• Identified sex-specific enhancer-promoter interactions regulating genes involved in X-chromosome inactivation (XCI).
• Discovered sex-specific cis- and trans-regulatory domains (CRDs and TRDs).
• Linked male-specific TRDs to metabolic pathways and female-specific TRDs to XCI-escape genes (XIST, JPX), underscoring TRDs' role in SCZ sex differences.

Conclusions:

• Provided an extensive characterization of sex differences in the brain epigenome.
• Highlighted the importance of sex-specific regulatory elements in understanding SCZ.
• Established the role of TRDs in deciphering sex differences in SCZ pathogenesis.