Pregnancy-specific glycoproteins: evolution, expression, functions and disease associations

Area of Science:

• Reproductive immunology
• Evolutionary biology
• Molecular endocrinology

Background:

• Pregnancy-specific glycoproteins (PSGs) are immunoglobulin superfamily members produced by placental trophoblasts.
• PSGs are secreted into maternal circulation, potentially influencing maternal immune and vascular functions, and acting locally within the placenta.
• They are also found in non-reproductive tissues, with deregulation linked to diseases like colorectal cancer.

Purpose of the Study:

• To explore the diverse roles of PSGs in pregnancy and other physiological contexts.
• To investigate the evolutionary history and gene family expansion of PSGs across mammalian species.
• To understand the functional conservation of PSGs despite gene family diversification.

Main Methods:

• Review of existing literature on PSG structure, function, and evolution.
• Comparative analysis of PSG gene families across different mammalian lineages.
• Examination of PSG expression patterns in reproductive and non-reproductive tissues.

Main Results:

• PSGs exhibit multifaceted roles, including modulation of maternal immune responses, vascular functions, and TGF-β activation.
• PSG gene families show significant evolutionary diversification in gene number and protein structure.
• Despite diversification, core PSG functions appear conserved across species, particularly in those with hemochorial placentation.

Conclusions:

• PSGs are key mediators of maternal-fetal communication with conserved functions, suggesting evolutionary adaptation driven by maternal-fetal conflict.
• The study highlights the dynamic evolution of PSG genes and their critical roles in pregnancy and potentially other diseases.