Transforming Growth Factor β1 Inhibits Placental Differentiation and Human Chorionic Gonadotropin and Human Placental Lactogen Secretion

Abstract

Previously, no inhibitors of placental differentiation have been described. In this study, we determined the effect of transforming growth factor beta 1 (TGF beta 1) on cytotrophoblast differentiation. Monolayer cultures of pure cytotrophoblasts were exposed to 0.001-10 ng/ml TGF beta 1 with and without the presence of 10 ng/ml epidermal growth factor (EGF), an inducer of placental differentiation. Over 7 days of culture, in 11 separate experiments, phase contrast microscopy demonstrated marked inhibition of EGF-induced syncytial formation by TGF beta 1. Basal human (h)CG and h-placental lactogen (PL) release were reduced compared to control by fractions of 0.75 (TGF beta 1/control) and 0.54, respectively. EGF alone induced fractional (EGF/control) increases in hCG and hPL release of 2.46 and 2.68, respectively. However, this stimulation was significantly inhibited by 10 ng/ml TGF beta 1. Dose-response studies showed that maximal TGF beta 1 inhibition of EGF-stimulated hormone secretion occurred at 0.1 ng/ml or more TGF beta 1. Partial differentiation (syncytium formation) occurred despite the presence of TGF beta 1, suggesting a portion of cytotrophoblasts were committed to differentiation at the time of culture. We conclude that TGF beta 1 acts as a major inhibitor of trophoblast differentiation and concomitant peptide hormone secretion.

Characterization of transforming growth factor-beta (TGF-beta) receptors on BeWo choriocarcinoma cells including the identification of a novel 38-kDa TGF-beta binding glycoprotein.

“…However, in another study, TGF-f31 was found to be inhibitory to trophoblast differentiation and hCG and hPL secretion (Morrish et al, 1991). Further studies are needed to differentiate the potencies of TGF-(31 and -(32 in controlling invasiveness and differentiation.…”

“…With respect to crosslinking effects, we have previously demonstrated that the apparently higher capacity of the primary trophoblast type III/betaglycan receptor for TGF-/1 than TGF-/2 was not due to an inherent difference in the crosslinking efficiency to 1251I-TGF-/1 versus 1251I-TGF-/32 (i.e., the type III/betaglycan receptor on control placental mesenchymal cell cultures was labeled to the same extent by 1251I-TGF-/1 and 1251I-TGF-/2 in affinity labeling saturation studies [Mitchell et al, 1992] (Mitchell et al, 1992) and some other cells types (Cheifetz et al, 1990 (Attisano et al, 1992 (MacKay and Danielpour, 1991). In addition, of the four TGF-3 binding components purified recently from porcine uterus (Ichijo et al, 1991) (Mitchell, unpublished observations The activities of TGF-f in extracellular matrix remodeling, growth inhibition, and immunosuppression have led various investigators to examine the roles of TGFf in trophoblast invasiveness (Lala and Graham, 1990;Tamada et al, 1990;Lala, 1991, 1992a,b), trophoblast differentiation (Morrish et al, 1991;, and in the maintenance of pregnancy (Altman et al, 1990;Clark et al, 1990Clark et al, , 1991Lea et al, 1992). A greater understanding of the control of trophoblast invasiveness is important for the treatment of certain conditions of pregnancy, such as the overinvasiveness of choriocarcinoma or the underinvasiveness of preeclampsia, as well as for cancer therapy in general.…”

“…The roles of growth factors in trophoblast function are poorly understood, although they are assumed to mediate their effects through various paracrine and autocrine pathways (for reviews see Pollard, 1988;Blay and Hollenberg, 1989;Ohlsson, 1989;Morrish, 1990). The activities of TGFf, notably in extracellular matrix remodeling, differentiation, and immunosuppression, point to potential roles for TGF-3 as a mediator of trophoblastic invasion of the uterus, trophoblast differentiation, and maintenance of pregnancy (Altman et al, 1990;Clark et al, 1990;1991;Lala and Graham, 1990;Tamada et al, 1990;Lala, 1991, 1992a,b;Morrish et al, 1991;Ritvos and Eramaa, 1991;Graham et al, 1992a,b;Lea et al, 1992). Placenta and amniotic fluid are both relatively rich sources of TGF-3 (Frolik et al, 1983;Altman et al, 1990), and the TGF-f2 isoform, in particular, has been implicated in placental function (Miller et al, 1989;Altman et al, 1990;Clark et al, 1990;1991;Lea et al, 1992 (Friedman and Skehan, 1979;Burres and Cass, 1987 Boston, MA, December, 1991(Lee et al, 1991Mitchell and O'Connor-McCourt, 1991b).…”

Adrenomedullin Is Decreased in Preeclampsia Because of Failed Response to Epidermal Growth Factor and Impaired Syncytialization

“…We have also shown that EGF stimulates and TGF-␤1 inhibits cytotrophoblast differentiation into syncytium. [25][26][27] Abnormalities in EGF action have been linked as well to intrauterine growth restriction (IUGR), which often accompanies severe PE. 28,29 Because of the possible roles of these cytokines in placental biology and pathophysiology, we wished to determine their effects on ADM secretion and whether such effects were different between normal and PE trophoblasts.…”

Adrenomedullin in mammalian embryogenesis

“…Other factors such as colony stimulating factor-1 (CSF-1) and granulocyte-macrophage colony stimulating factor (GM-CSF) also stimulate (García-Lloret et al, 1994;Morrish et al, 1987), whilst TGF␤1 inhibits (Morrish et al, 1991) in vitro biochemical and morphological syncytiotrophoblast differentiation. Interestingly, using a subtractive hybridization procedure, AM was found to be one of the genes whose expression was increased by EGF-induced differentiation (Morrish et al, 1996).…”