Preimplantation factor (PIF* proprietary) is a unique, 15 amino acid peptide, secreted by only viable embryos which exerts local and systemic immunemodulatory effects. This study attempts to elucidate the precise mechanism of action of PIF in decidual cells (DC).
Using our established model of in vitro investigation of DC (Krikun G, et al, J Clin Endocrinol Metab, 2005), we studied DC isolated from non-pregnant human endometrial stromal cells (HESC) and 1st trimester of pregnancy (FT-HESC). DC were isolated, purified, cultured and incubated in the presence of 100nM synthetic PIF or media (used as control) in triplicate for 24h. Cells were extracted and gene expression was analyzed using Affymetrix chip microarray analysis (U133 Plus 2.0 Array). DC proteins were determined by using quantitative mass spectrometry analysis. For gene and preteomic experiments, PIF exposed DC were compared to PIF unexposed DC. Statistical analysis was performed using student's t test, with significance set at p<0.05.
Both gene and proteomic analysis respectively demonstrate PIF's notable effects in three different pathways: 1) Immune pathway: FKBP15 was downregulated in HESC 2.84, and its protein, FK506-15, was increased 2.20 fold (pval 0.01). 2) Adhesion pathway: SORBS2 was upregulated 14 fold in FTDC gene, and SORBS1 protein was increased 2.11 fold (pval 0.002). Both have SRC Homology 3 (SH3) domain. 3) Apoptotic pathway: The BCL2 gene was the most downregulated gene in FTDC. Ubiquitin specific peptidases (USP) 12 was significantly down regulated in HESC and upregulated in FTDC. UCHL1 Ubiquitin carboxyl-terminal hydrolase isozyme L1 was increased 2.7 fold (pval 0.03).
This study significantly advances the understanding of PIF's action. PIF likely plays a role in: 1) regulating immunity, possibly through a calcineurin pathway; 2) promoting embryo-decidual adhesion. 3) regulating adaptive apoptotic processes relative to peri-implantation events.
© 2009 Mosby, Inc. Published by Elsevier Inc. All rights reserved.