Preimplantation factor (PIF) upregulates first trimester toll like receptor-2, supporting the role of PIF as an embryo derived factor influencing maternal innate immunity

Abstract

RECEPTOR-2, SUPPORTING THE ROLE OF PIF AS AN EMBRYO DERIVED FACTOR INFLUENCING MATERNAL INNATE IMMUNITY MICHAEL PAIDAS, GRACIELA KRIKUN, LYNN BUCHWALDER, FREDERICK SCHATZ, KARL GODLEWSKI, EYTAN R. BARNEA, Yale University School of Medicine, Department Obstetrics, Gynecology and Reproductive Sciences, CoDirector, Yale Blood Center for Women and Children, New Haven, Connecticut, Yale University, Obstetrics and Gynecology & Reproductive Sciences, New Haven, Connecticut, UMDNJ/Robert Wood Johnson Medical School, CAMcare Health Center, Cherry Hill, New Jersey OBJECTIVE: Preimplantation factor (PIF), is a novel, embryo-derived, small peptide which appears very early in pregnancy. The maternal host response in pregnancy must allow for tolerance of the implanting embryo, and preservation of maternal defense mechanisms against viral and bacterial pathogens. We posit that: a) PIF may act as an immune modulating agent, capable of augmenting maternal defense mechanisms via upregulation of Toll-like receptor (TLR)-2, a transmembrane protein involved in pathogen recognition; b) PIF may will influence decidual cell (DC) production of interleukins (IL), metalloproteinases (MMP) involved in extracellular matrix degradation, and angiogenesis. STUDY DESIGN: DCs were obtained from women undergoing first trimester (TRI) elective terminations or third TRI repeat Cesarean sections. DCs were isolated, purified, and seeded on polystyrene tissue culture dishes. The effects of PIF on TLR-2 protein expression was carried out using first TRI DCs. Third TRI DCs were used to study the effects of PIF on well characterized markers of DC function, as measured by ELISA. Western blotting for TLR-2 and beta actin was conducted using established methods. Densitometric analyses were carried out with the Image J NIH analysis software. PIF (10nM) was used as an agonist to DC culture. Values were expressed as TLR2/beta actin ratio, correcting for total DNA content. RESULTS: PIF incubation was associated with a two-fold increase in TLR-2 expression. We were unable to detect any change in secreted levels of the following third TRI DC products: IL-6, IL-8, IL-11, plasminogen activator inhibitor-1, MMP-3, vascular endothelial growth factor. CONCLUSION: In this preliminary study, PIF significantly upregulates first trimester TLR-2 expression, suggesting that PIF may augment the maternal innate immune response. Maintainence of host defense mechanisms must occur as the host prepares to accept the implanting embryo. Further studies are needed to confirm PIF’s effects on TLR-2, evaluate downstream effects, and determine whether PIF regulates first TRI DC function.