Seasonally variant gene expression in full-term human placenta

Area of Science:

• Human placental biology
• Developmental biology
• Chronobiology

Background:

• Seasonal environmental factors impact human health and development.
• The placenta is a key mediator between maternal and fetal systems, influencing development.
• Understanding placental responses to seasonal cues can elucidate birth season-health outcome associations.

Purpose of the Study:

• To investigate whether human placental tissue is influenced by seasonal cues.
• To identify differentially expressed genes in the placenta related to the season of birth.

Main Methods:

• Differential gene expression analysis was performed on full-term human placental tissue.
• Cosinor analysis was used to assess rhythmic gene expression patterns.
• Enrichment analyses identified overrepresented transcription factors and pathways.

Main Results:

• 583 transcripts showed differential expression between summer and winter births (False Discovery Rate q < 0.05).
• Genes such as BHLHE40, MIR210HG, and HILPDA were upregulated in winter births.
• Enrichment analysis revealed overrepresentation of transcription factors (HIF1A, VDR, CLOCK) and pathways related to ribosomal activity and infection.
• Approximately 11.9% of analyzed placental transcripts exhibited rhythmic expression.

Conclusions:

• The human placenta responds to seasonal influences.
• Placental gene expression patterns suggest it functions as a peripheral biological clock.
• These findings offer a molecular basis for observed associations between season of birth and health outcomes.