Adiponectin promotes syncytialisation of BeWo cell line and primary trophoblast cells

<p>Abstract</p> <p>Background</p> <p>In human pregnancy, a correct placentation depends on trophoblast proliferation, differentiation, migration and invasion. These processes are highly regulated by placental hormones, growth factors and cytokines. Recently, we have shown that adiponectin, an adipokine, has anti-proliferative effects on trophoblastic cells. Here, we complete this study by demonstrating that adiponectin modulates BeWo and human villous cytotrophoblast cell differentiation.</p> <p>Results</p> <p>We showed that hCG secretion was up-regulated by adiponectin treatment in both BeWo cells and human cytotrophoblasts from very early placentas (5-6 weeks). The expression of two trophoblast differentiation markers, leptin and syncytin 2, was also up-regulated by adiponectin in BeWo cells. Moreover, adiponectin treatment induced a loss of E-cadherin staining in these cells. In parallel, we demonstrated that AdipoR1 and AdipoR2 are up-regulated during forskolin induced BeWo cell differentiation, reinforcing the role of adiponectin in trophoblast syncytialization. SiRNA mediated down-regulation of AdipoR1 and AdipoR2 was used to demonstrate that adiponectin effects on differentiation were essentially mediated by these receptors. Finally, using a specific inhibitor, we demonstrated that the PKA signalling pathway could be one pathway involved in adiponectin effects on trophoblast differentiation.</p> <p>Conclusion</p> <p>Adiponectin enhances the differentiation process of trophoblast cells and could thus be involved in functional syncytiotrophoblast formation.</p

Rôle de l'adiponectine dans les cellules trophoblastiques humaines (implication dans les processus de prolifération, différenciation et invasion cellulaires)

L implantation de l embryon, et la formation du placenta sont deux étapes essentielles au début d une grossesse. Le cytotrophoblaste extra-villeux et le syncytiotrophoblaste se différencient dès les premiers stades de la placentation. Le syncytiotrophoblaste est la cellule endocrine du placenta. Le cytotrophoblaste extra-villeux assure l ancrage du placenta dans le myomètre grâce à ses capacités invasives et migratoires. Dès l implantation, un dialogue foeto-maternel s instaure, impliquant des hormones et des cytokines produites par le placenta et les différents tissus maternels qui vont réguler la formation de ces différents types cellulaires assurant les fonctions essentielles du placenta. L adiponectine est une adipocytokine produite par le tissu adipeux et présente en forte concentrations dans la circulation sanguine. Son rôle principal est de moduler le métabolisme glucido-lipidique. Cependant, dans de nombreux tissus l adiponectine exerce des effets antiprolifératifs, pro-invasifs et pro-différenciants. L adiponectine et ses récepteurs AdipoR1 et AdipoR2 sont présents à l interface foeto-maternelle. Le placenta est donc une cible potentielle de l adiponectine. Nous avons souhaité déterminer les effets directs de l adiponectine sur les fonctions trophoblastiques. Dans une première partie, nous avons démontré que l adiponectine in vitro diminue la prolifération des lignées trophoblastiques JEG-3 et BeWo. Dans une seconde partie, nous avons montré que l adiponectine stimule la différenciation du trophoblaste villeux en syncytiotrophoblaste. De plus, l adiponectine favorise la sécrétion d hormones placentaires telles que l hCG et la leptine, et stimule l expression de la protéine fusogène syncytine-2. Enfin, dans une troisième partie, nous avons montré que l adiponectine stimule l invasion du trophoblaste extravilleux en modulant la balance MMP / TIMP. L ensemble de ces travaux a permis de mettre en évidence pour la première fois que l adiponectine est un nouveau régulateur positif de la fonction trophoblastique. En effet, l adiponectine favorise la formation d un placenta fonctionnel doté des capacités sécrétoires du syncytiotrophoblaste et des capacités d ancrage dans le myomètre assurées par l invasion des trophoblastes extravilleux.Embryo implantation and placental formation are two essential steps in the beginning of a pregnancy. The extra-villous trophoblast and the cytotrophoblast differenciate during the first steps of placentation. The syncytiotrophoblast is the endocrine cell of the placenta. The role of the invasive extra-villous trophoblast is to anchor the placenta in the endometrium. During the implantation the placenta and the endometrium produce several hormones and cytokines that regulate the formation of these two cell types that are essential for placental functions. Adiponectin as an adipocytokine produced by the adipose tissue and circulating at high concentrations in human blood. The major role of adiponectin is to regulate the energy homeostasis. Moreover, in many other tissues, adiponectin exerts anti-proliferative, proinvasive and pro-differenciating actions. Adiponectin and its receptors AdipoR1 and AdipoR2 are present at the foeto-maternal interface. Thus, the placenta could be sensible to adiponectin. We aimed to determine the direct effects of adiponectin on placental functions. In the first part of this work, we demonstrated that adiponectin in vitro reduces proliferation of BeWo and JEG-3 cell lines. Secondly, we showed that adiponectin stimulates syncytiotrophoblast differentiation from villous trophoblast. Moreover, adiponectin upregulates the secretion of placental hormones as hCG and Leptin and the expression of the fusogenic protein syncytin-2. Finally, we showed that adiponectin stimulates extravillous trophoblast invasion by modulating the MMP/TIMP balance. This work thus shows for the first time that adiponectin is a new positive regulator of trophoblastic functions. Indead, adiponectine promotes the formation of a functionnal placenta with secretory capacities from the syncytiotrophoblast and anchoring capacities from the extra-villous trophoblasts.VERSAILLES-BU Sciences et IUT (786462101) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Does Physical Exercise Always Improve Bone Quality in Rats?

For decades, the osteogenic effect from different physical activities on bone in rodents remained uncertain. This literature review presents for the first time the effects on five exercise models (treadmill running, wheel running, swimming, resistance training and vibration modes) in three different experimental rat groups (males, females, osteopenic) on bone quality. The bone parameters presented are bone mineral density, micro-architectural and mechanical properties, and osteoblast/osteocyte and osteoclast parameters. This review shows that physical activities have a positive effect (65% of the results) on bone status, but we clearly observed a difference amongst the different protocols. Even if treadmill running is the most used protocol, the resistance training constitutes the first exercise model in term of osteogenic effects (87% of the whole results obtained on this model). The less osteogenic model is the vibration mode procedure (31%). It clearly appears that the gender plays a role on the bone response to swimming and wheel running exercises. Besides, we did not observe negative results in the osteopenic population with impact training, wheel running and vibration activities. Moreover, about osteoblast/osteocyte parameters, we conclude that high impact and resistance exercise (such jumps and tower climbing) seems to increase bone formation more than running or aerobic exercise. Among the different protocols, literature has shown that the treadmill running procedure mainly induces osteogenic effects on the viability of the osteocyte lineage in both males and females or ovariectomized rats; running in voluntary wheels contributes to a negative effect on bone metabolism in older male models; whole-body vertical vibration is not an osteogenic exercise in female and ovariectomized rats; whereas swimming provides controversial results in female models. For osteoclast parameters only, running in a voluntary wheel for old males, the treadmill running program at high intensity in ovariectomized rats, and the swimming program in a specific ovariectomy condition have detrimental consequences

Synchrotron ultraviolet microspectroscopy on rat cortical bone: involvement of tyrosine and tryptophan in the osteocyte and its environment.

Alcohol induced osteoporosis is characterized by a bone mass decrease and microarchitecture alterations. Having observed an excess in osteocyte apoptosis, we aimed to assess the bone tissue biochemistry, particularly in the osteocyte and its environment. For this purpose, we used a model of alcohol induced osteoporosis in rats. Bone sections of cortical bone were investigated using synchrotron UV-microspectrofluorescence at subcellular resolution. We show that bone present three fluorescence peaks at 305, 333 and 385 nm, respectively corresponding to tyrosine, tryptophan and collagen. We have determined that tyrosine/collagen and tryptophan/collagen ratios were higher in the strong alcohol consumption group. Tryptophan is related to the serotonin metabolism involved in bone formation, while tyrosine is involved in the activity of tyrosine kinases and phosphatases in osteocytes. Our experiment represents the first combined synchrotron UV microspectroscopy analysis of bone tissue with a quantitative biochemical characterization in the osteocyte and surrounding matrix performed separately

Effect of the alcohol consumption on osteocyte cell processes: a molecular imaging study.

International audienceWe have previously shown microarchitectural tissue changes with cellular modifications in osteocytes following high chronic alcohol dose. The aim of this study was to assess the dose effect of alcohol consumption on the cytoskeleton activity, the cellular lipid content and modulation of differentiation and apoptosis in osteocyte. Male Wistar rats were divided into three groups: Control (C), Alcohol 25% v/v (A25) or Alcohol 35% v/v (A35) for 17 weeks. Bone mineral density (BMD) was assessed by DXA, osteocyte empty lacunae, lacunae surface, bone marrow fat with bright field microscopy. Osteocyte lipid content was analysed with transmission electron microscopy (TEM) and epifluorescence microscopy. Osteocyte apoptosis was analysed with immunolabelling and TEM. Osteocyte differentiation and cytoskeleton activity were analysed with immunolabelling and real time quantitative PCR. At the end of the protocol, BMD was lower in A25 and A35 compared with C, while the bone marrow lipid content was increased in these groups. More empty osteocyte lacunae and osteocyte containing lipid droplets in A35 were found compared with C and A25. Cleaved caspase-3 staining and chromatin condensation were increased in A25 and A35 versus C. Cleaved caspase-3 was increased in A35 versus A25. CD44 and phosphopaxillin stainings were higher in A35 compared with C and A25. Paxillin mRNA expression was higher in A35 versus A25 and C and sclerostin mRNA expression was higher in A35 versus C. We only observed a dose effect of alcohol consumption on cleaved caspase-3 osteocyte immunostaining levels and on the number of lipid droplets in the bone marrow

Effects of adiponectin on human trophoblast invasion

International audienceAdiponectin is an adipokine with insulin-sensitizing, anti-inflammatory, anti-atherogenic, and anti-proliferative effects. The expression of specific adiponectin receptors in the placenta and in the endometrium suggests a role for this cytokine in placental development, but this role has not yet been elucidated. The invasion of trophoblast cells during the first trimester of pregnancy being crucial to placentation process, we have studied adiponectin effects on human trophoblast invasive capacities. We found that adiponectin stimulated human trophoblast cell migration in HTR-8/SVneo cells in a dose-independent manner. In addition, adiponectin also significantly enhanced invasion of HTR-8/SVneo cells and of human extravillous trophoblast from first trimester placenta. These pro-invasive effects of adiponectin in human trophoblasts seem to be mediated in part via increased matrix metalloproteinases (MMP2 and MMP9) activities and via repression of TIMP2 mRNA expression. Our results suggest that adiponectin could be a positive regulator of the early invasion process by modulating the MMP/TIMP balance. Moreover, these results provide an insight into the role of adiponectin in pathological conditions characterized by insufficient or excessive trophoblast invasion

Tyrosine/Collagen and Tryptophan/Collagen ratios on osteocyte and surrounding matrix for the A25 group.

<p><b>A</b>: Comparison between osteocyte and matrix for the Tyrosine/Collagen ratio. <b>B</b>: Comparison between osteocyte and matrix for the Tryptophan/Collagen ratio. shows a significant difference between the ratios (p<0.05). Ratios are expressed as mean ± standard deviation (sd).</p

Bone sample ROI investigated on transmission image obtained on Synchrotron UV beamline.

<p>Tibia sections of 300 µm were cut. Magnifications (×50, ×100, ×200) represent histologic section after toluidine blue staining (white scale bars 80, 40, 20 µm, respectively). Magnification ×400 represents visible confocal microscopy acquired on UV beamline (the white scale bar indicates 10 µm).</p