Surfactant Protein-A (SP-A) Selectively Inhibits Prostaglandin F2α (PGF2α) Production in Term Decidua: Implications for the Onset of Labor

• Published in: The journal of clinical endocrinology and metabolism Vol. 96; no. 4; pp. E624 - E632
• Main Authors: Snegovskikh, Victoria V, Bhandari, Vineet, Wright, Jo Rae, Tadesse, Serkalem, Morgan, Thomas, MacNeill, Colin, Foyouzi, Nastaran, Park, Joong Shin, Wang, Yuguang, Norwitz, Errol R
• Format: Journal Article
• Language: English
• Published: Chevy Chase, MD Endocrine Society 01.04.2011; Copyright by The Endocrine Society
• Subjects: Hot Topics in Translational Endocrinology
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.2010-1496

SP-A from endometrium/decidua selectively inhibits PGF2α, and the observed decrease in decidua SP-A may be critical to “decidual activation” and onset of labor at term. Context: Labor is characterized by “decidual activation” with production of inflammatory mediators. Recent data suggest that surfactant protein-A (SP-A) may be critical to the onset of labor in mice. Whether this is also true in humans is unclear. Objectives: The aim was to investigate: 1) the expression of SP-A at the maternal-fetal interface; 2) the effect of SP-A on the production of inflammatory mediators by human decidua; and 3) the association between single nucleotide polymorphisms in maternal SP-A genes and spontaneous preterm birth. Research Design and Methods: In situ expression of SP-A was investigated by immunohistochemistry and quantitative RT-PCR. Term decidual stromal cells were isolated, purified, and treated with/without SP-A (1–100 μg/ml), IL-1β, and/or thrombin. Levels of inflammatory mediators [IL-6, IL-8, TNFα, matrix metalloproteinase-3, monocyte chemotactic protein-1, IL-1β, PGE2, prostaglandin F2α (PGF2α)] and angiogenic factors (soluble fms-like tyrosine kinase-1, vascular endothelial growth factor) were measured in conditioned supernatant by ELISA and corrected for protein content. The effect of SP-A on eicosanoid gene expression was measured by quantitative RT-PCR. Results: SP-A localized to endometrium/decidua. High-dose SP-A (100 μg/ml) inhibited PGF2α by term decidual stromal cells without affecting the production of other inflammatory mediators, and this effect occurred at a posttranscriptional level. Decidual SP-A expression decreased significantly with labor. Single nucleotide polymorphisms in the SP-A genes do not appear to be associated with preterm birth. Conclusions: SP-A is produced by human endometrium/decidua, where it significantly and selectively inhibits PGF2α production. Its expression decreases with labor. These novel observations suggest that decidual SP-A likely plays a critical role in regulating prostaglandin production within the uterus, culminating at term in decidual activation and the onset of labor.