Aromatase in the human central nervous system

Area of Science:

• Neuroendocrinology
• Molecular Biology
• Human Anatomy

Background:

• Aromatase facilitates local oestrogen production, influencing numerous central nervous system (CNS) functions.
• Limited information exists regarding aromatase expression patterns within the human CNS.

Purpose of the Study:

• To investigate aromatase gene expression in diverse human brain regions.
• To analyze the alternative splicing of aromatase gene exons, which dictates tissue-specific expression.
• To compare expression levels and splicing patterns between male and female brain tissues.

Main Methods:

• Human brain tissue samples (4 men, 2 women) were obtained post-mortem.
• Reverse transcriptase (RT)-polymerase chain reaction (PCR) was employed to quantify aromatase mRNA levels.
• Alternative splicing of multiple exon 1 variants of the aromatase gene was analyzed.

Main Results:

• Aromatase mRNA levels were highest in the pons, thalamus, hypothalamus, and hippocampus.
• Brain-specific exon 1f, fibroblast-type 1b, and gonadal-type 1d were expressed.
• Exons 1d and 1f were predominantly utilized in the hypothalamus, thalamus, and amygdala, regions showing higher overall mRNA expression.
• No significant differences in exon utilization or mRNA expression were observed between male and female brains.

Conclusions:

• Aromatase is expressed broadly across multiple regions of the human brain.
• Both male and female brains exhibit similar patterns of aromatase expression and gene splicing.
• These findings highlight the potential role of locally produced oestrogen in the adult human CNS.