Background: Human trophoblast invasion and differentiation are essential for a successful pregnancy outcome. Dysregulation of these processes can lead to placental pathologies such as pre-eclampsia. The molecular mechanisms; however, are poorly understood. Interleukin (IL)11--a cytokine that regulates endometrial epithelial cell adhesion, trophoblast motility and invasion during implantation--may be involved in some of these processes.
Methods and results: The effect of IL11 on protein expression was investigated in trophoblastic HTR8/SVneo cells and primary extravillous trophoblasts (EVTs) purified from first- trimester placentas. Two-dimension (2D)-differential in-gel electrophoresis analyses revealed that 731 spots were significantly differentially regulated by IL11 in HTR8/SVneo cells: seven spots were analyzed by liquid chromatography-tandem mass spectrometry and 14 unique proteins identified. Protein disulfide isomerase family A, member 3 (PDIA3; endoplasmic reticulum p57) and glucose-regulated protein 78 (GRP78) were further validated to be regulated by IL11 in HTR8/SVneo and primary EVT. One dimension western blot analysis confirmed that PDIA3 was down-regulated in EVT. 2D western blot analysis revealed that GRP78 was post-translationally modified following IL11 treatment. Moreover, IL11 stimulated the secretion of GRP78 in EVT.
Conclusions: Data suggest that IL11, possibly via signal transducers and activators of transcription 3 signaling pathway, regulates PDIA3 protein expression and modification/secretion of GRP78. This is the first study to identify PDIA3 and GRP78 as IL11 targets in invasive trophoblasts and identifies a possible mechanism by which IL11 regulates trophoblast function.