Reproductive biologies
Abstract
The pathogenesis of preeclampsia and other hypertensive disorders of pregnancy remains poorly-defined despite the substantial burden of maternal and neonatal morbidity associated with these conditions. In particular, the role of genetic variants as determinants of disease susceptibility remains unknown. Storkhead-box protein 1 (STOX1) was first identified as a preeclampsia risk gene through family-based genetic linkage studies in which loss-of-function variants were proposed to underlie increased preeclampsia susceptibility. We generated a genetic Stox1 loss-of-function mouse model (Stox1 KO), to evaluate whether STOX1 regulates blood pressure in pregnancy. Pregnant Stox1 KO mice developed gestational hypertension evidenced by a significant increase in blood pressure compared with wild type by E17.5. While severe renal, placental, or fetal growth abnormalities were not observed, the Stox1 KO phenotype was associated with placental vascular and extracellular matrix abnormalities. Mechanistically, we found that gestational hypertension in Stox1 KO mice resulted from activation of the uteroplacental renin-angiotensin system. We confirmed this mechanism by showing that treatment of pregnant Stox1 KO mice with an angiotensin II receptor blocker rescued the phenotype. Our study demonstrates the utility of genetic mouse models for uncovering links between genetic variants and effector pathways implicated in the pathogenesis of hypertensive disorders of pregnancy.
Authors
Jacqueline G. Parchem, Keizo Kanasaki, Soo Bong Lee, Megumi Kanasaki, Joyce L. Yang, Yong Xu, Kadeshia M. Earl, Rachel A. Keuls, Vincent H. Gattone, Raghu Kalluri
Abstract
Successful implantation is associated with a unique spatial pattern of vascular remodeling, characterized by profound peripheral neovascularization surrounding a periembryo avascular niche. We hypothesized that hyaluronan controls the formation of this distinctive vascular pattern encompassing the embryo. This hypothesis was evaluated by genetic modification of hyaluronan metabolism, specifically targeted to embryonic trophoblast cells. The outcome of altered hyaluronan deposition on uterine vascular remodeling and postimplantation development were analyzed by MRI, detailed histological examinations, and RNA sequencing of uterine NK cells. Our experiments revealed that disruption of hyaluronan synthesis, as well as its increased cleavage at the embryonic niche, impaired implantation by induction of decidual vascular permeability, defective vascular sinus folds formation, breach of the maternal-embryo barrier, elevated MMP-9 expression, and interrupted uterine NK cell recruitment and function. Conversely, enhanced deposition of hyaluronan resulted in the expansion of the maternal-embryo barrier and increased diffusion distance, leading to compromised implantation. The deposition of hyaluronan at the embryonic niche is regulated by progesterone-progesterone receptor signaling. These results demonstrate a pivotal role for hyaluronan in successful pregnancy by fine-tuning the periembryo avascular niche and maternal vascular morphogenesis.
Authors
Ron Hadas, Eran Gershon, Aviad Cohen, Ofir Atrakchi, Shlomi Lazar, Ofra Golani, Bareket Dassa, Michal Elbaz, Gadi Cohen, Raya Eilam, Nava Dekel, Michal Neeman
Abstract
Metabolic syndrome (MetS), which is associated with chronic inflammation, predisposes males to hypogonadism and subfertility. The underlying mechanism of these pathologies remains poorly understood. Homozygous leptin-resistant obese db/db mice are characterized by small testes, low testicular testosterone, and a reduced number of Leydig cells. Here we report that IL-1β, CCL2 (also known as MCP-1), and corticosterone concentrations were increased in the testes of db/db mice relative to those in WT controls. Cultured murine and human Leydig cells responded to cytokine stress with increased CCL2 release and apoptotic signals. Chemical inhibition of CCL2 rescued Leydig cell function in vitro and in db/db mice. Consistently, we found that Ccl2-deficient mice fed with a high-energy diet were protected from testicular dysfunction compared with similarly fed WT mice. Finally, a cohort of infertile men with a history of MetS showed that reduction of CCL2 plasma levels could be achieved by weight loss and was clearly associated with recovery from hypogonadism. Taken together, we conclude that CCL2-mediated chronic inflammation is, to a large extent, responsible for the subfertility in MetS by causing damage to Leydig cells.
Authors
Qingkui Jiang, Constanze C. Maresch, Sebastian Friedrich Petry, Agnieszka Paradowska-Dogan, Sudhanshu Bhushan, Yongsheng Chang, Christine Wrenzycki, Hans-Christian Schuppe, Petr Houska, Michaela F. Hartmann, Stefan A. Wudy, Lanbo Shi, Thomas Linn
Abstract
WNK1 is an atypical kinase protein ubiquitously expressed in humans and mice. A mutation in its encoding gene causes hypertension in humans which is associated with abnormal ion homeostasis. WNK1 is critical for in vitro decidualization in human endometrial stromal cells, thereby demonstrating its importance in female reproduction. Using a mouse model, WNK1 was ablated in the female reproductive tract to define its in vivo role in uterine biology. Loss of WNK1 altered uterine morphology, causing endometrial epithelial hyperplasia, adenomyotic features and a delay in embryo implantation, ultimately resulting in compromised fertility. Combining transcriptomic, proteomic and interactomic analyses revealed a novel regulatory pathway whereby WNK1 represses AKT phosphorylation through the phosphatase PP2A in endometrial cells from both humans and mice. We show that WNK1 interacts with PPP2R1A, the alpha isoform of the PP2A scaffold subunit. This maintains the levels of PP2A subunits and stabilizes its activity, which then dephosphorylates AKT. Therefore, loss of WNK1 reduced PP2A activity, causing AKT hypersignaling. Using FOXO1 as a readout of AKT activity, we demonstrate that there was escalated FOXO1 phosphorylation and nuclear exclusion, leading to a disruption in the expression of genes that are crucial for embryo implantation.
Authors
Ru-pin Alicia Chi, Tianyuan Wang, Chou-Long Huang, San-Pin Wu, Steven Young, John Lydon, Francesco DeMayo
Human Tregs at the maternal-fetal interface show site-specific adaptation reminiscent of tumor Tregs
Abstract
Regulatory T cells (Tregs) are crucial for maintaining maternal immune-tolerance against the semi-allogeneic fetus. We investigated the elusive transcriptional profile and functional adaptation of human uterine Tregs (uTregs) during pregnancy. Uterine biopsies, from placental bed (=maternal-fetal interface) and incision site (=control), and blood were obtained from women with uneventful pregnancies undergoing Caesarean section. Tregs and CD4+ non-Tregs were isolated for transcriptomic profiling by Cel-Seq2. Results were validated on protein and single cell level by flow cytometry. Placental bed uterine Tregs (uTregs) showed elevated expression of Treg signature markers, including FOXP3, CTLA-4 and TIGIT. Their transcriptional profile was indicative of late-stage effector Treg differentiation and chronic activation, with increased expression of immune checkpoints GITR, TNFR2, OX-40, 4-1BB, genes associated with suppressive capacity (HAVCR2, IL10, LAYN, PDCD1), and transcription factors MAF, PRDM1, BATF, and VDR. uTregs mirrored non-Treg Th1 polarization and tissue-residency. The particular transcriptional signature of placental bed uTregs overlapped strongly with that of tumor-infiltrating Tregs, and was remarkably pronounced at the placental bed compared to uterine control site. Concluding, human uTregs acquire a differentiated effector Treg profile similar to tumor-infiltrating Tregs, specifically at the maternal-fetal interface. This introduces the novel concept of site-specific transcriptional adaptation of Tregs within one organ.
Authors
Judith Wienke, Laura Brouwers, Leone M. van der Burg, Michal Mokry, Rianne C. Scholman, Peter G. J. Nikkels, Bas B. van Rijn, Femke van Wijk
Abstract
The initiation of puberty is driven by an upsurge in hypothalamic gonadotropin-releasing hormone (GnRH) secretion. In turn, GnRH secretion upsurge depends on the development of a complex GnRH neuroendocrine network during embryonic life. Although delayed puberty (DP) affects up to 2% of the population, is highly heritable, and is associated with adverse health outcomes, the genes underlying DP remain largely unknown. We aimed to discover regulators by whole-exome sequencing of 160 individuals of 67 multigenerational families in our large, accurately phenotyped DP cohort. LGR4 was the only gene remaining after analysis that was significantly enriched for potentially pathogenic, rare variants in 6 probands. Expression analysis identified specific Lgr4 expression at the site of GnRH neuron development. LGR4 mutant proteins showed impaired Wnt/β-catenin signaling, owing to defective protein expression, trafficking, and degradation. Mice deficient in Lgr4 had significantly delayed onset of puberty and fewer GnRH neurons compared with WT, whereas lgr4 knockdown in zebrafish embryos prevented formation and migration of GnRH neurons. Further, genetic lineage tracing showed strong Lgr4-mediated Wnt/β-catenin signaling pathway activation during GnRH neuron development. In conclusion, our results show that LGR4 deficiency impairs Wnt/β-catenin signaling with observed defects in GnRH neuron development, resulting in a DP phenotype.
Authors
Alessandra Mancini, Sasha R. Howard, Federica Marelli, Claudia P. Cabrera, Michael R. Barnes, Michael J.E. Sternberg, Morgane Leprovots, Irene Hadjidemetriou, Elena Monti, Alessia David, Karoliina Wehkalampi, Roberto Oleari, Antonella Lettieri, Valeria Vezzoli, Gilbert Vassart, Anna Cariboni, Marco Bonomi, Marie Isabelle Garcia, Leonardo Guasti, Leo Dunkel
Abstract
Changes in maternal immunity during pregnancy can result in an altered immune state and, as a natural perturbation, this provides an opportunity to understand functional interactions of the immune system in vivo. We report characterisation of maternal peripheral immune phenotypes for 33 longitudinally sampled normal pregnancies, using clinical measurements of complete blood counts and major immune cell populations, as well as high parameter flow cytometry for 30 different leukocyte antigens characterising 79 cell populations, and monitoring of 1305 serum proteins using the SomaLogic platform. Cellular analyses characterised transient changes in T cell polarization, and more persistent alterations in T and B cell subset frequencies and activation. Serum proteomic analysis identified a novel set of 7 proteins that are predictive of gestational age: DDR1, PLAU, MRC1, ACP5, ROBO2, IGF2R, and GNS. We further show that gestational age can be predicted from the parameters obtained by complete blood count tests and clinical flow cytometry characterizing 5 major immune cell populations. Inferring gestational age from this routine clinical phenotyping data could be useful in resource limited settings which lack obstetric ultrasound. Overall, both the cellular and proteomic analyses validate previously reported phenotypic immunological changes of pregnancy, and uncover new alternations and predictive markers.
Authors
Richard Apps, Yuri Kotliarov, Foo Cheung, Kyu Lee Han, Jinguo Chen, Angelique Biancotto, Ashley L. Babyak, Huizhi Zhou, Rongye Shi, Lisa A. Barnhart, Sharon M. Osgood, Yasmine Belkaid, Steven M. Holland, John S. Tsang, Christa Zerbe
Abstract
Few therapeutic methods exist for preventing preterm birth (PTB), or delivery before completing 37 weeks of gestation. In the US, progesterone (P4) supplementation is the only FDA-approved drug for use in preventing recurrent spontaneous PTB. However, P4 has limited effectiveness, working in only approximately one-third of cases. Computational drug repositioning leverages data on existing drugs to discover novel therapeutic uses. We used a rank-based pattern-matching strategy to compare the differential gene expression signature for PTB to differential gene expression drug profiles in the Connectivity Map database and assigned a reversal score to each PTB-drug pair. Eighty-three drugs, including P4, had significantly reversed differential gene expression compared with that found for PTB. Many of these compounds have been evaluated in the context of pregnancy, with 13 belonging to pregnancy category A or B — indicating no known risk in human pregnancy. We focused our validation efforts on lansoprazole, a proton-pump inhibitor, which has a strong reversal score and a good safety profile. We tested lansoprazole in an animal inflammation model using LPS, which showed a significant increase in fetal viability compared with LPS treatment alone. These promising results demonstrate the effectiveness of the computational drug repositioning pipeline to identify compounds that could be effective in preventing PTB.
Authors
Brian L. Le, Sota Iwatani, Ronald J. Wong, David K. Stevenson, Marina Sirota
Abstract
Adequate iron supply during pregnancy is essential for fetal development. However, how fetal or amniotic fluid iron levels are regulated during healthy pregnancy, or pregnancies complicated by intraamniotic infection or inflammation (IAI) is unknown. We evaluated amniotic fluid and fetal iron homeostasis in normal and complicated murine, macaque, and human pregnancy. In mice, fetal iron endowment was affected by maternal iron status but amniotic fluid iron concentrations changed little during maternal iron deficiency or excess. In murine and macaque models of inflamed pregnancy, the fetus responded to maternal systemic inflammation or IAI by rapidly upregulating hepcidin and lowering iron in fetal blood, without altering amniotic fluid iron. In humans, elevated cord blood hepcidin with accompanying hypoferremia was observed in pregnancies with antenatal exposure to IAI compared to those that were non-exposed. Hepcidin was also elevated in human amniotic fluid from pregnancies with IAI compared to those without IAI, but amniotic fluid iron levels did not differ between the groups. Our studies in mice, macaques, and humans demonstrate that amniotic fluid iron is largely unregulated but that the rapid induction of fetal hepcidin by inflammation and consequent fetal hypoferremia are conserved mechanisms that may be important in fetal host defense.
Authors
Allison L. Fisher, Veena Sangkhae, Pietro Presicce, Claire A. Chougnet, Alan H. Jobe, Suhas G. Kallapur, Sammy M. Tabbah, Catalin S. Buhimschi, Irina A. Buhimschi, Tomas Ganz, Elizabeta Nemeth
Abstract
During pregnancy the maternal pancreatic islets of Langerhans undergo adaptive changes to compensate for gestational insulin resistance. Kisspeptin has been shown to stimulate insulin release, through its receptor, GPR54. The placenta releases high levels of kisspeptin into the maternal circulation, suggesting a role in modulating the islet adaptation to pregnancy. In the present study we show that pharmacological blockade of endogenous kisspeptin in pregnant mice resulted in impaired glucose homeostasis. This glucose intolerance was due to a reduced insulin response to glucose as opposed to any effect on insulin sensitivity. A β cell–specific GPR54-knockdown mouse line was found to exhibit glucose intolerance during pregnancy, with no phenotype observed outside of pregnancy. Furthermore, in pregnant women circulating kisspeptin levels significantly correlated with insulin responses to oral glucose challenge and were significantly lower in women with gestational diabetes (GDM) compared with those without GDM. Thus, kisspeptin represents a placental signal that plays a physiological role in the islet adaptation to pregnancy, maintaining maternal glucose homeostasis by acting through the β cell GPR54 receptor. Our data suggest reduced placental kisspeptin production, with consequent impaired kisspeptin-dependent β cell compensation, may be a factor in the development of GDM in humans.
Authors
James E. Bowe, Thomas G. Hill, Katharine F. Hunt, Lorna I.F. Smith, Sian J.S. Simpson, Stephanie A. Amiel, Peter M. Jones
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