Roberta Romagnoli

First trimester human trophoblast expresses both interferon-γ and interferon-γ-receptor

Interferon-gamma (IFN-gamma) is a lymphokine, produced by activated T lymphocytes, which plays a key regulatory role in the host immunological responses. In addition, IFN-gamma is expressed by human and porcine trophoblast. As IFN-gamma exerts its biological functions through specific cell surface receptors and a great number of IFN-gamma receptors (IFN-gamma R) have been purified from human placenta, we have examined the relative distribution of IFN-gamma and IFN-gamma R in human placental tissues at different stages of pregnancy. By using immunohistochemical analysis and monoclonal antibodies, it was found that IFN-gamma expression is intense in the first trimester but almost imperceptible at term, whereas the expression of IFN-gamma R is present at both stages of pregnancy. For both lymphokine and receptor, the most intense expression was observed in villous syncytiotrophoblast and in extravillous interstitial trophoblast. From these results it appears that the expression of IFN-gamma R in trophoblast is related to the presence of the lymphokine in the early phase of gestation but not later. On this basis, it can be argued that IFN-gamma exerts its functional role via an autocrine and/or a paracrine loop mainly during the first trimester.

Environmental Levels of para-Nonylphenol Are Able to Affect Cytokine Secretion in Human Placenta

Background para-Nonylphenol (p-NP) is a metabolite of alkylphenols widely used in the chemical industry and manufacturing. It accumulates in the environment, where it acts with estrogen-like activity. We previously showed that p-NP acts on human placenta by inducing trophoblast differentiation and apoptosis. Objective The aim of the present study was to investigate the effect of p-NP on cytokine secretion in human placenta. Methods In vitro cultures of chorionic villous explants from human placenta in the first trimester of pregnancy were treated with p-NP (10−13, 10−11, and 10−9 M) in 0.1% ethanol as vehicle. Culture medium was collected after 24 hr and assayed by specific immunoassays for the cytokines granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon-γ (IFN-γ), interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, and tumor necrosis factor-α (TNF-α). Results p-NP modulated cytokine secretion by inducing the release of GM-CSF, IFN-γ, IL-1β, IL-4, and IL-10, with a maximum effect at 10−11 M. It reduced the release of TNF-α at 10−13 M, whereas levels of IL-2 and IL-5 remained below the detection limit. IL-6 and IL-8 levels were 100–1,000 times higher than those of other cytokines, and they were not affected by p-NP. We observed significant differences from controls (ethanol alone) only for GM-CSF and IL-10. Conclusion An unbalanced cytokine network at the maternal–fetal interface may result in implantation failure, pregnancy loss, or other complications. The effects of extremely low doses of p-NP on the placental release of cytokines raise considerable concerns about maternal exposure to this endocrine disruptor during pregnancy.

Cytokines in the viviparous reproduction of squamate reptiles: Interleukin-1α (IL-1α) and IL-1β in placental structures of a skink

Placental viviparity is known in many species of squamate reptiles. Among these, some scincids have developed an epithelio-chorial chorio-allantoic placenta which in the structure of its central ridged zone is similar to those of certain therian mammalian species. A broad range of immunoregulatory peptides, cytokines, has been identified at the maternofetal interface of several species of mammals, either with invasive or non-invasive types of placenta. Thus we began to study whether interleukin-1, which is considered to play a crucial role in mammalian pregnancy, might also be involved in the viviparity of reptilian species. Placentae of Chalcides chalcides L. were processed by immunohistochemistry and incubated in a culture medium for different times. A very strong immunoreactivity for interleukin-1 alpha (IL-1 alpha) and for interleukin-1 beta (IL-1 beta) was present in the chorial epiblast and in uterine epithelial cells, with varying degree and localization in different periods of pregnancy. IL-1 beta was also released into the medium at different amounts during incubation. In light of the mammalian data, our results suggest that the role of cytokines in pregnancy may represent a significant event in the evolution of placental viviparity.

Pro-inflammatory Cytokines in Animal and Human Gestation

The story of cytokines in pregnancy began about 30 years ago, approximately in concomitance with the understanding that cytokines are autocrine-paracrine regulators of physiological processes. Pro-inflammatory cytokines are predominant in the early and late events of gestation, e.g. pregnancy establishment and parturition, both of which have been described as inflammatory-like events. Pro-inflammatory cytokines are also produced in response to microbes constantly in contact with the female reproductive tract. While a pro-inflammatory response is beneficial to successful pregnancy, an exaggerated response, as may occur for an unresolved infection, could result in an unfavorable pregnancy outcome in animals and humans. Therapeutic strategies are required to avoid the risks to the health of fetus and mother. In this review, we discuss the involvement of pro-inflammatory cytokines in pregnancy at implantation and parturition, including the pathologies which might be related to an alteration of the cytokine levels. We also deal with the use of anti-cytokines and/or anti-inflammatory mediators to antagonize the action of pro-inflammatory cytokines. Finally we discuss the potential of animal models to evaluate the association of cytokines in the establishment and maintenance of pregnancy.

Macrophage migration inhibitory factor is up-regulated in human first-trimester placenta stimulated by soluble antigen of Toxoplasma gondii, resulting in increased monocyte adhesion on villous explants.

Considering the potential role of macrophage migration inhibitory factor (MIF) in the inflammation process in placenta when infected by pathogens, we investigated the production of this cytokine in chorionic villous explants obtained from human first-trimester placentas stimulated with soluble antigen from Toxoplasma gondii (STAg). Parallel cultures were performed with villous explants stimulated with STAg, interferon-gamma (IFN-gamma), or STAg plus IFN-gamma. To assess the role of placental MIF on monocyte adhesiveness to human trophoblast, explants were co-cultured with human myelomonocytic THP-1 cells in the presence or absence of supernatant from cultures treated with STAg (SPN), SPN plus anti-MIF antibodies, or recombinant MIF. A significantly higher concentration of MIF was produced and secreted by villous explants treated with STAg or STAg plus IFN-gamma after 24-hour culture. Addition of SPN or recombinant MIF was able to increase THP-1 adhesion, which was inhibited after treatment with anti-MIF antibodies. This phenomenon was associated with intercellular adhesion molecule expression by villous explants. Considering that the processes leading to vertical dissemination of T. gondii remain widely unknown, our results demonstrate that MIF production by human first-trimester placenta is up-regulated by parasite antigen and may play an essential role as an autocrine/paracrine mediator in placental infection by T. gondii.

The Translationally Controlled Tumor Protein Is a Novel Calcium Binding Protein of the Human Placenta and Regulates Calcium Handling in Trophoblast Cells

Abstract The translationally controlled tumor protein (TPT1, also known as TCTP) is a highly conserved, abundantly expressed protein found in mammals as well as in a wide range of other organisms of both the animal and plant kingdom. Initially considered as a growth-related protein, later studies showed TPT1 is endowed with multiple biological activities, including calcium binding. The present study aimed to evaluate the expression of TPT1 in the human placenta and to examine the functional role of the protein in the calcium binding and homeostasis of trophoblast cells. Samples were analyzed by Western blot, reverse transcription-polymerase chain reaction and immunohistochemistry. The effect of TPT1 knockdown by small interfering RNA (siRNA) on calcium uptake and buffering was assessed in the HTR-8/SVneo cell line. TPT1 protein and mRNA were detected in first-trimester and term placenta. In the tissue, TPT1 was localized in the villous trophoblast. TPT1 expression significantly increased during gestation, with the higher protein and mRNA levels reached at term. Recombinant placental TPT1 bound calcium in vitro, while downregulation of the protein levels by siRNA in HTR-8/SVneo cells was associated with a reduced cellular calcium-uptake activity and buffering capacity. These data demonstrate, for the first time, the expression of TPT1 in the human placenta and support a direct role of the protein in placental calcium transport.

Expression and localization of ATP binding cassette transporter A1 (ABCA1) in first trimester and term human placenta

ATP binding cassette transporter A1 (ABCA1) is a membrane transporter which performs cellular efflux of cholesterol and phospholipid. ABCA1s cholesterol transporting role in human placenta appears to be crucial for normal fetal development. Despite the critical importance of cholesterol in fetal development, expression of ABCA1 in the human placenta throughout gestation and its specific cellular localization have not been known yet. We therefore investigated ABCA1 expression in human placenta at first trimester and term by western blot and quantitative real-time PCR (qRT-PCR) analysis. Furthermore, its localization was investigated by immunohistochemistry and confocal microscopy. Expression of ABCA1 did not differ significantly between first trimester and term placenta at both protein and mRNA levels. Immunohistochemical data demonstrated that ABCA1 was widely localized in the villous and extravillous cytotrophoblast as well as in some stromal and endothelial cells. Confocal microscopy imaging data showed that ABCA1 was localized largely at the basolateral and to some extent at the apical side of first trimester villous cytotrophoblast cell membranes. Placental expression of ABCA1 throughout the gestation and its specific cellular localization indicate that this transporter may play an important role in materno-fetal cholesterol transfer.

17β-Estradiol modulates the macrophage migration inhibitory factor secretory pathway by regulating ABCA1 expression in human first-trimester placenta

Successful pregnancy involves a series of events, most of them mediated by hormones and cytokines. Estrogens, besides being important for placental growth and embryo development, have a marked effect on the immune system exerting either pro- or anti-inflammatory properties. Numerous studies suggest that estrogens directly affect cellular function, including cytokine production. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine involved in pregnancy, particularly during the earlier stages of placentation. Since reports on mice have shown that estrogens modulate MIF, herein we investigated the effect of estrogens on human placental MIF. By using an in vitro model of first-trimester chorionic villous explants, we found that 17beta-estradiol (E(2)) was able to modulate the release of MIF in a dose-dependent manner (10(-12) vs. 10(-9) M, P < 0.05; 10(-9) vs. 10(-5) M, P < 0.05; 10(-12) vs. 10(-5) M, P < 0.001). Unlike MIF release, no significant change in tissue MIF protein or MIF mRNA was observed. We showed evidence that E(2) concentrations (10(-9) and 10(-5) M) act on placental tissue downregulating the mRNA and protein expression of the ATP-binding cassette transporter protein A1, a membrane transporter involved in MIF secretion. These findings emphasize the mutual cooperation between hormones and cytokines and suggest that increasing estrogen levels with advancing gestation may have a major role in regulating placental MIF secretion.

Macrophage Migration Inhibitory Factor in Fetoplacental Tissues from Preeclamptic Pregnancies with or without Fetal Growth Restriction

The proinflammatory cytokine MIF (macrophage migration inhibitory factor) is involved in physiological and pathological processes in pregnancy. MIF maternal serum levels are increased in preeclampsia (PE). We hypothesize that pregnancy tissues are the source of MIF overexpression in PE. MIF protein was studied in maternal sera, placental tissues, fetal membranes, and umbilical cord of 8 control and 20 PE pregnancies: 10 with normal fetal growth (PE-AGA) and 10 with fetal growth restriction (PE-FGR). MIF levels were significantly higher in PE-AGA membranes than in controls and PE-FGR. In PE-FGR, MIF cord concentrations were higher than in PE-AGA while MIF placental levels were lower than in controls. MIF maternal serum levels were higher in PE, compared to controls, and the difference was mainly due to PE-FGR samples. These data support MIF involvement in PE pathogenesis and suggest that different pregnancy tissues contribute to MIF production in PE with and without fetoplacental compromise.

Presence of Macrophage Migration Inhibitory Factor in Human Milk: Evidence in the Aqueous Phase and Milk Fat Globules

Human milk is a source of bioactive substances regulating the development and activity of the newborn immune system. Human milk has been found to contain a number of cytokines, including interleukins, growth factors, and colony stimulating factors. In the present study, we assessed 10 specimens of human milk for the presence of macrophage migration inhibitory factor (MIF), a cytokine recently described in several human reproductive organs and tissues. Using biochemical as well as immunologic techniques, we showed that MIF is abundantly present in human milk, mostly distributed in the lipid layer and in the aqueous phase. Fractionation of the lipid layer showed that MIF is highly concentrated inside milk fat globules. In view of its proinflammatory features, we speculate that milk MIF may protect the newborn against infection and play a role in preserving the functionality of the lactating mammary gland. Furthermore, the localization of MIF in lipid globules suggests a possible strategy for the protection of milk cytokines from the gastric barrier.