Investigation of expressions and functions of ubiquitin proteasome system proteins in human placenta in different periods of pregnancy

During implantation and placental development, there are molecular mechanisms in the invasion and migration of trophoblasts. Recent studies have reported the importance of p97/VCP (Valosin-Containing Protein) and SVIP (Small VCP-Interacting Protein) in invasion of cancer cells and Ubiquitin-Proteasome System (UPS). Although many studies have been conducted during pregnancy, the roles of p97/VCP and SVIP are unknown. In the first stage, the aim of the study was to compare the expressions of these proteins in different trimester human placentas. In the second stage, it was aimed to examine the possible effects of these proteins on invasion and migration in functional studies with extravillous trophoblast cells. Histochemical evaluations and Scanning Electron Microscopy were used in placentas. Protein and gene analyses were performed by immunohistochemistry, immunofluorescence, Western Blot and qRT-PCR. Expressions were suppressed through extravillous trophoblast cell line HTR-8/SVneo by p97/VCP inhibitor (DBeQ) administration and p97/VCP-SVIP siRNA transfections. Changes in invasion and migration were determined by real-time analysis system (xCELLigence). In the 1st trimester, p97/VCP and SVIP expressions were found to be intense in cytotrophoblasts and syncyiotrophoblasts. In the Western Blot and qRT-PCR findings, the expressions in the 1st trimester decreased in the 2nd trimester and then increased again. Expressions of LC3II and p62 increased throughout pregnancy. It was determined that SVIP expressions decreased, LC3II and p62 increased significantly after DBeQ. DBeQ and p97/VCP siRNA transfection reduced invasion and migration of the cells. In addition, there was an increase in the SVIP siRNA groups in invasion and migration. As a result, the determination that p97/VCP and SVIP, which play a role in UPS, were expressed at different levels in trimesters revealed the importance of these proteins in human placental development. Also, it was revealed that extravillous trophoblasts affected invasion and migration, and that they might be effective in pathologies such as pregnancy sustainability and preeclampsia.