Decoding the amniotic membrane transcriptome during equine ascending placentitis

Area of Science:

• Veterinary Science
• Reproductive Biology
• Immunology

Background:

• The equine amniotic membrane's role in disease, particularly placentitis, is poorly understood.
• It acts as a physical barrier and may influence fetal lung development via surfactant synthesis.
• Understanding molecular changes in placentitis is crucial for addressing abortion, preterm birth, and stillbirth.

Purpose of the Study:

• To characterize gene expression in the equine amniotic membrane during experimentally induced ascending placentitis.
• To identify molecular pathways involved in the fetal-maternal tissue response to placentitis.
• To elucidate the amniotic membrane's active role in immune responses during pregnancy complications.

Main Methods:

• Experimentally induced ascending placentitis in equine models (n=6 per group).
• RNA sequencing and bioinformatic analysis to identify differentially expressed genes (DEGs).
• Immunohistochemistry to validate protein expression of key genes (TLR4, PTGS2).

Main Results:

• Identified 288 differentially expressed genes in the placentitis group compared to controls.
• Observed upregulation of toll-like receptors (TLR4), prostaglandin synthesis (PTGS2, PTGES), apoptosis (MMP9, CASP3), and hypoxia genes (SOD2, BNIP3, HMOX1).
• Confirmed TLR4 and PTGS2 protein expression via immunohistochemistry; linked DEGs to toll receptor signaling pathways.

Conclusions:

• The equine amniotic membrane is not merely a passive barrier but actively participates in the immune response to ascending placentitis.
• Upregulated pathways suggest a significant role in inflammation, apoptosis, and hypoxia during placentitis.
• Findings provide insights into mechanisms of placentitis-induced pregnancy loss and potential therapeutic targets.