Seasonal Influences on Human Placental Transcriptomes Associated with Spontaneous Preterm Birth.

Area of Science:

• Reproductive biology
• Environmental health
• Genomics

Background:

• High ambient temperatures during pregnancy are linked to increased preterm birth (PTB) risks.
• The underlying mechanisms, potentially involving placental function, remain unclear.

Purpose of the Study:

• To investigate placental gene expression changes associated with high ambient temperatures and PTB.
• To identify specific molecular pathways and biological processes affected by heat exposure during pregnancy.

Main Methods:

• Differential gene expression analysis of bulk RNA-seq data from human placentas.
• Gene set enrichment analysis (GSEA) and gene ontology (GO) analysis.
• Comparison between preterm and term placentas from warmer and colder months in the UK.

Main Results:

• Identified 48 differentially expressed genes in preterm placentas from warmer months, predominantly inflammatory cytokines and chemokines.
• GSEA revealed enrichment of inflammatory pathways (e.g., NF-κB, IL17, Toll-like receptor) in preterm placentas from warmer months.
• GO analysis showed enhanced immune and chemotaxis-related processes in preterm placentas from warmer months, not observed in term placentas.

Conclusions:

• Maternal exposure to warm temperatures during pregnancy alters placental transcriptomes towards inflammation and immune dysregulation.
• These placental changes are associated with preterm birth.
• The findings suggest a potential mechanism linking environmental heat exposure to PTB.