Transforming Growth Factor Beta Regulates Proliferation and Invasion of Rat Placental Cell Lines1

Abstract

Implantation of an embryo in the endometrium is a critical step for continuation of pregnancy, and implantation failure is a major cause of infertility. In rats, the implantation process involves invasion of the endometrial epithelial lining by the trophoblastic cells in order to reach the underlying stromal cells. Transforming growth factor beta (TGFB) is a multifunctional cytokine that regulates proliferation, differentiation, and invasiveness of multiple cell lineages. We used rat HRP-1 and RCHO-1 placental cell lines to perform this study. HRP-1 cells were derived from midgestation chorioallantoic placental explants of the outbred Holtzman rat, whereas RCHO-1 cells were established from a rat choriocarcinoma. MTT proliferation assays revealed that each TGFB isoform decreased HRP-1 cell growth in a dose-dependent manner, whereas RCHO-1 cells were resistant to the growth-suppressive effect of TGFB1 and TGFB3. Only TGFB2 reduced RCHO-1 cell proliferation. Activation of ERK, MAPK14 (p38 MAPK), or SMAD pathways is known to play a role in cell proliferation, and we found that TGFB activates these pathways in both HRP-1 and RCHO-1 cells in an isoform-specific manner. MTT proliferation assays revealed that ERK pathway is partially implicated in TGFB3-reduced HRP-1 cell proliferation. Hoechst nuclear staining and caspase-3 cleavage demonstrated that TGFB isoforms failed to induce apoptosis in both cell lines. Matrigel invasion assays showed that both HRP-1 and RCHO-1 cells exhibit intrinsic invasive ability under untreated conditions. The capacity of HRP-1 cells to invade the Matrigel was selectively increased by TGFB2 and TGFB3, whereas all TGFB isoforms could increase the invasiveness of RCHO-1 cells. These important functional studies progressively reveal a key role for TGFB in regulating proliferation and invasiveness of placental cells.

Changes in Functional Activity of JEG-3 Trophoblast Cell Line in the Presence of Factors Secreted by Placenta

“…These cytokines are not secreted during incubation of placental explants, probably due to their ability to bind to extracellular matrix components (72,73). On the other hand, an increase in TGFb in this case (65) may act as an inhibitor of proliferation (74) and migration (75) of trophoblast. It has been previously shown that the cytokines variously affect proliferation and migration of extravillous trophoblast.…”

Bridging endometrial receptivity and implantation: network of hormones, cytokines, and growth factors

“…Recently, it has been demonstrated that TGF-b signaling pathway plays an important role in remodeling rat endometrium by modulating the activity of PI3-K/AKT survival pathways, along with the inhibition of anti-apoptotic protein XIAP levels, thus inducing apoptosis in decidual cells (Caron et al 2009). In addition, TGF-b isoforms inhibit trophoblast proliferation and increase invasive property of HRP-1 and RCHO-1 rat trophoblast cells by activating Smad and p38 MAPK pathways (Lafontaine et al 2011).…”

Schistosoma japonicum Soluble Egg Antigens Attenuate Invasion in a First Trimester Human Placental Trophoblast Model

“…We next assessed the ability of the HTR8/SVneo cell line to invade through matrigel, a model of extracellular matrix, and a transwell insert after being treated with SEA, using a standard invasion assay [32]. Cells were pretreated with SEA for 24 h to minimize any direct effect of SEA on the matrigel.…”