HYPOXIA AND REPRODUCTIVE HEALTH: Oxygen and development of the human placenta

Development of the human placenta takes place in contrasting oxygen concentrations at different stages of gestation, from ~20 mmHg during the first trimester rising to ~60 mmHg at the start of the second trimester before gradually declining to ~40 mmHg at term. In view of these changes, the early placenta has been described as ‘hypoxic’. However, placental metabolism is heavily glycolytic, supported by the rich supply of glucose from the endometrial glands, and there is no evidence of energy compromise. On the contrary, the trophoblast is highly proliferative, with the physiological low-oxygen environment promoting maintenance of stemness in progenitor populations. These conditions favour the formation of the cytotrophoblastic shell that encapsulates the conceptus and interfaces with the endometrium. Extravillous trophoblast cells on the outer surface of the shell undergo an epithelial-mesenchymal transition and acquire invasive potential. Experimental evidence suggests that these changes may be mediated by the higher oxygen concentration present within the placental bed. Interpreting in vitro data is often difficult, however, due to the use of non-physiological oxygen concentrations and trophoblast-like cell lines or explant models. Trophoblast is more vulnerable to hyperoxia or fluctuating levels of oxygen than to hypoxia, and some degree of placental oxidative stress likely occurs in all pregnancies towards term. In complications of pregnancy, such as early-onset pre-eclampsia, malperfusion generates high levels of oxidative stress, causing release of factors that precipitate the maternal syndrome. Further experiments are required using genuine trophoblast progenitor cells and physiological concentrations to fully elucidate the pathways by which oxygen regulates placental development.

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Oxygen regulation of macrophage migration inhibitory factor in human placenta

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00086.2006 ◽

2007 ◽

Vol 292 (1) ◽

pp. E272-E280 ◽

Cited By ~ 23

Author(s):

Francesca Ietta ◽

Yuanhong Wu ◽

Roberta Romagnoli ◽

Nima Soleymanlou ◽

Barbara Orsini ◽

...

Keyword(s):

High Altitude ◽

Migration Inhibitory Factor ◽

Macrophage Migration Inhibitory Factor ◽

Inhibitory Factor ◽

Extravillous Trophoblast ◽

Macrophage Migration ◽

Low Oxygen ◽

Placental Development

Macrophage migration inhibitory factor (MIF) is an important proinflammatory cytokine involved in regulation of macrophage function. In addition, MIF may also play a role in murine and human reproduction. Although both first trimester trophoblast and decidua express MIF, the regulation and functional significance of this cytokine during human placental development remains unclear. We assessed MIF expression throughout normal human placental development, as well as in in vitro (chorionic villous explants) and in vivo (high altitude placentae) models of human placental hypoxia. Dimethyloxalylglycine (DMOG), which stabilizes hypoxia inducible factor-1 under normoxic conditions, was also used to mimic the effects of hypoxia on MIF expression. Quantitative real-time PCR and Western blot analysis showed high MIF protein and mRNA expression at 7–10 wk and lower levels at 11–12 wk until term. Exposure of villous explants to 3% O2 resulted in increased MIF expression and secretion relative to standard conditions (20% O2). DMOG treatment under 20% O2 increased MIF expression. In situ hybridization and immunohistochemistry showed elevated MIF expression in low oxygen-induced extravillous trophoblast cells. Finally, a significant increase in MIF transcript was observed in placental tissues from high-altitude pregnancies. Hence, three experimental models of placental hypoxia (early gestation, DMOG treatment, and high altitude) converge in stimulating increased MIF, supporting the conclusion that placental-derived MIF is an oxygen-responsive cytokine highly expressed in physiological in vivo and in in vitro low oxygen conditions.

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Trophoblast lineage specification, differentiation and their regulation by oxygen tension

Journal of Endocrinology ◽

10.1530/joe-17-0402 ◽

2018 ◽

Vol 236 (1) ◽

pp. R43-R56 ◽

Cited By ~ 24

Author(s):

Ching-Wen Chang ◽

Anna K Wakeland ◽

Mana M Parast

Keyword(s):

Oxygen Tension ◽

First Trimester ◽

Arterial Blood Flow ◽

Extravillous Trophoblast ◽

Low Oxygen ◽

Epithelial Stem Cells ◽

Placental Development ◽

Trophoblast Differentiation ◽

Arterial Blood ◽

Low Oxygen Tension

Development of the early embryo takes place under low oxygen tension. Under such conditions, the embryo implants and the trophectoderm, the outer layer of blastocyst, proliferate, forming the cytotrophoblastic shell, the early placenta. The cytotrophoblasts (CTBs) are the so-called epithelial ‘stem cells’ of the placenta, which, depending on the signals they receive, can differentiate into either extravillous trophoblast (EVT) or syncytiotrophoblast (STB). EVTs anchor the placenta to the uterine wall and remodel maternal spiral arterioles in order to provide ample blood supply to the growing fetus. STBs arise through CTB fusion, secrete hormones necessary for pregnancy maintenance and form a barrier across which nutrient and gas exchange can take place. The bulk of EVT differentiation occurs during the first trimester, before the onset of maternal arterial blood flow into the intervillous space of the placenta, and thus under low oxygen tension. These conditions affect numerous signaling pathways, including those acting through hypoxia-inducible factor, the nutrient sensor mTOR and the endoplasmic reticulum stress-induced unfolded protein response pathway. These pathways are known to be involved in placental development and disease, and specific components have even been identified as directly involved in lineage-specific trophoblast differentiation. Nevertheless, much controversy surrounds the role of hypoxia in trophoblast differentiation, particularly with EVT. This review summarizes previous studies on this topic, with the intent of integrating these results and synthesizing conclusions that resolve some of the controversy, but then also pointing to remaining areas, which require further investigation.

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Proteome Profiling of Human Placenta Reveals Developmental Stage-Dependent Alterations in Protein Signature

10.21203/rs.3.rs-261849/v1 ◽

2021 ◽

Author(s):

Sara Khorami Sarvestani ◽

Sorour Shojaeian ◽

Negar Vanaki ◽

Behrouz Gharesi-Fard ◽

Mehdi Amini ◽

...

Keyword(s):

Human Placenta ◽

First Trimester ◽

Full Term ◽

Chemical Stimulus ◽

Health It ◽

Low Oxygen ◽

Placental Development ◽

Liquid Chromatography Tandem Mass ◽

Complex Organ ◽

Protein Signature

Abstract Introduction Placenta is a complex organ that plays a significant role in the maintenance of pregnancy health. It is a dynamic organ that undergoes dramatic changes in growth and development at different stages of gestation. In the first-trimester, the conceptus develops in a low oxygen environment that favors organogenesis in the embryo and cell proliferation and angiogenesis in the placenta; later in pregnancy, higher oxygen concentration is required to support the rapid growth of the fetus. This transition, which appears unique to the human placenta, must be finely tuned through successive rounds of protein signature alterations. This study compares placental proteome in normal first-trimester (FT) and term human placentas (TP). MethodsNormal human first-trimester and term placental samples were collected and differentially expressed proteins were identified using two-dimensional liquid chromatography-tandem mass spectrometry.ResultsDespite the overall similarities, 120 proteins were differently expressed in first and term placentas. Out of these, 120 proteins, expression of 72 was up-regulated and that of 48 was down-regulated in the first when compared with the full term placentas. Twenty out of 120 differently expressed proteins were sequenced, among them seven showed increased (GRP78, PDIA3, ENOA, ECH1, PRDX4, ERP29, ECHM), eleven decreased (TRFE, ALBU, K2C1, ACTG, CSH2, PRDX2, FABP5, HBG1, FABP4, K2C8, K1C9) expression in first-trimester compared to the full-term placentas and two proteins exclusively expressed in first-trimester placentas (MESD, MYDGF). DiscussionAccording to Reactome and PANTHER softwares, these proteins were mostly involved in response to chemical stimulus and stress, regulation of biological quality, programmed cell death, hemostatic and catabolic processes, protein folding, cellular oxidant detoxification, coagulation and retina homeostasis. Elucidation of alteration in protein signature during placental development would provide researchers with a better understanding of the critical biological processes of placentogenesis and delineate proteins involved in regulation of placental function during development.

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Resveratrol inhibits autophagy in HTR-8/SVneo model by alleviating trophoblast oxidative stress

10.21203/rs.3.rs-97399/v1 ◽

2020 ◽

Author(s):

Meihe LI ◽

Minchao KANG ◽

Peng AN ◽

Huimin DANG ◽

Xin XU

Keyword(s):

Oxidative Stress ◽

First Trimester ◽

Normal Function ◽

Beclin 1 ◽

Extravillous Trophoblast ◽

Successful Outcome ◽

Beneficial Effects ◽

Vitro Model ◽

Related Proteins

Abstract BackgroundThe normal function of the placenta at each time stage of pregnancy is essential to a successful outcome. Placental dysfunction and increased oxidative stress and autophagy are the cause of a series of severe pregnancy complications. Resveratrol is a potent antioxidant that has shown beneficial effects in many diseases. We aim to investigate whether excessive autophagy is associated with oxidative stress in the trophoblast oxidative stress model. Resveratrol was taken to clarify its role in excessive autophagy of placental trophoblasts. MethodsWe established an in vitro model of oxidative stress by exposing the human first-trimester extravillous trophoblast cell line HTR-8/SVneo to H2O2. Levels of autophagy-related proteins (LC3, Beclin-1, p53 and mTOR) were detected by western blot.ResultsTreatment with resveratrol significantly ameliorated H2O2-induced cytotoxicity, morphological damage, oxidative stress and autophagy. Mechanistically, resveratrol restored the levels of autophagy-related proteins including LC3-II, Beclin-1 and p53, mTOR that were dysregulated by H2O2.ConclusionsResveratrol may protect human trophoblasts against H2O2-induced oxidative stress by reducing excessive autophagy, thus ensuring the normal biological functions of trophoblasts.

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Cadherins in the human placenta – epithelial–mesenchymal transition (EMT) and placental development

Placenta ◽

10.1016/j.placenta.2010.06.017 ◽

2010 ◽

Vol 31 (9) ◽

pp. 747-755 ◽

Cited By ~ 104

Author(s):

M.I. Kokkinos ◽

P. Murthi ◽

R. Wafai ◽

E.W. Thompson ◽

D.F. Newgreen

Keyword(s):

Human Placenta ◽

Epithelial Mesenchymal Transition ◽

Placental Development ◽

Mesenchymal Transition

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Proteome profiling of human placenta reveals developmental stage-dependent alterations in protein signature

Clinical Proteomics ◽

10.1186/s12014-021-09324-y ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Sara Khorami Sarvestani ◽

Sorour Shojaeian ◽

Negar Vanaki ◽

Behrouz Ghresi-Fard ◽

Mehdi Amini ◽

...

Keyword(s):

Human Placenta ◽

First Trimester ◽

Full Term ◽

Chemical Stimulus ◽

Health It ◽

Low Oxygen ◽

Placental Development ◽

Liquid Chromatography Tandem Mass ◽

Normal Human ◽

Protein Signature

Abstract Introduction Placenta is a complex organ that plays a significant role in the maintenance of pregnancy health. It is a dynamic organ that undergoes dramatic changes in growth and development at different stages of gestation. In the first-trimester, the conceptus develops in a low oxygen environment that favors organogenesis in the embryo and cell proliferation and angiogenesis in the placenta; later in pregnancy, higher oxygen concentration is required to support the rapid growth of the fetus. This oxygen transition, which appears unique to the human placenta, must be finely tuned through successive rounds of protein signature alterations. This study compares placental proteome in normal first-trimester (FT) and term human placentas (TP). Methods Normal human first-trimester and term placental samples were collected and differentially expressed proteins were identified using two-dimensional liquid chromatography-tandem mass spectrometry. Results Despite the overall similarities, 120 proteins were differently expressed in first and term placentas. Out of these, 72 were up-regulated and 48 were down-regulated in the first when compared with the full term placentas. Twenty out of 120 differently expressed proteins were sequenced, among them seven showed increased (GRP78, PDIA3, ENOA, ECH1, PRDX4, ERP29, ECHM), eleven decreased (TRFE, ALBU, K2C1, ACTG, CSH2, PRDX2, FABP5, HBG1, FABP4, K2C8, K1C9) expression in first-trimester compared to the full-term placentas and two proteins exclusively expressed in first-trimester placentas (MESD, MYDGF). Conclusion According to Reactome and PANTHER softwares, these proteins were mostly involved in response to chemical stimulus and stress, regulation of biological quality, programmed cell death, hemostatic and catabolic processes, protein folding, cellular oxidant detoxification, coagulation and retina homeostasis. Elucidation of alteration in protein signature during placental development would provide researchers with a better understanding of the critical biological processes of placentogenesis and delineate proteins involved in regulation of placental function during development.

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Knockdown of Splicing Complex Protein PCBP2 Reduces Extravillous Trophoblast Differentiation Through Transcript Switching

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.671806 ◽

2021 ◽

Vol 9 ◽

Author(s):

Danai Georgiadou ◽

Souad Boussata ◽

Remco Keijser ◽

Dianta A. M. Janssen ◽

Gijs B. Afink ◽

...

Keyword(s):

Cell Cycle ◽

Hellp Syndrome ◽

Rna Splicing ◽

Ex Vivo ◽

First Trimester ◽

Cellular Growth ◽

Extravillous Trophoblast ◽

Placental Development ◽

Alternative Mrna Splicing

Mutations in the LINC-HELLP non-coding RNA (HELLPAR) have been associated with familial forms of the pregnancy-specific HELLP syndrome. These mutations negatively affect extravillous trophoblast (EVT) differentiation from a proliferative to an invasive state and disturb the binding of RNA splicing complex proteins PCBP1, PCBP2, and YBX1 to LINC-HELLP. In this study, by using both in vitro and ex vivo experiments, we investigate if these proteins are involved in the regulation of EVT invasion during placentation. Additionally, we study if this regulation is due to alternative mRNA splicing. HTR-8/SVneo extravillous trophoblasts and human first trimester placental explants were used to investigate the effect of siRNA-mediated downregulation of PCBP1, PCBP2, and YBX1 genes on the differentiation of EVTs. Transwell invasion assays and proliferation assays indicated that upon knockdown of PCBP2 and, to a lesser extent, YBX1 and PCBP1, EVTs fail to differentiate toward an invasive phenotype. The same pattern was observed in placental explants where PCBP2 knockdown led to approximately 80% reduction in the number of explants showing any EVT outgrowth. Of the ones that still did show EVT outgrowth, the percentage of proliferating EVTs was significantly higher compared to explants transfected with non-targeting control siRNAs. To further investigate this effect of PCBP2 silencing on EVTs, we performed whole transcriptome sequencing (RNA-seq) on HTR-8/SVneo cells after PCBP2 knockdown. PCBP2 knockdown was found to have minimal effect on mRNA expression levels. In contrast, PCBP2 silencing led to a switch in splicing for a large number of genes with predominant functions in cellular assembly and organization, cellular function and maintenance, and cellular growth and proliferation and the cell cycle. EVTs, upon differentiation, alter their function to be able to invade the decidua of the mother by changing their cellular assembly and their proliferative activity by exiting the cell cycle. PCBP2 appears to be a paramount regulator of these differentiation mechanisms, where its disturbed binding to LINC-HELLP could contribute to dysfunctional placental development as seen in the HELLP syndrome.

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Differentiation of first trimester cytotrophoblast to extravillous trophoblast involves an epithelial–mesenchymal transition

Placenta ◽

10.1016/j.placenta.2015.10.013 ◽

2015 ◽

Vol 36 (12) ◽

pp. 1412-1418 ◽

Cited By ~ 64

Author(s):

Sonia DaSilva-Arnold ◽

Joanna L. James ◽

Abdulla Al-Khan ◽

Stacy Zamudio ◽

Nicholas P. Illsley

Keyword(s):

Epithelial Mesenchymal Transition ◽

First Trimester ◽

Extravillous Trophoblast ◽

Mesenchymal Transition

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Oxygen governs Galβ1–3GalNAc epitope in human placenta

AJP Cell Physiology ◽

10.1152/ajpcell.00407.2012 ◽

2013 ◽

Vol 305 (9) ◽

pp. C931-C940 ◽

Cited By ~ 8

Author(s):

Leonardo Ermini ◽

Jayonta Bhattacharjee ◽

Antonella Spagnoletti ◽

Nicoletta Bechi ◽

Silvia Aldi ◽

...

Keyword(s):

Oxygen Tension ◽

Human Placenta ◽

Physiological State ◽

First Trimester ◽

Signal Molecules ◽

Control Mechanisms ◽

Low Oxygen ◽

Placental Development ◽

Human Trophoblast ◽

Cell Functions

It is becoming increasingly apparent that the dynamics of glycans reflect the physiological state of cells involved in several cell functions including growth, response to signal molecules, migration, as well as adhesion to, interaction with, and recognition of other cells. The presence of glycoconjugates in human placenta suggests their major role in maternal-fetal exchanges, intercellular adhesion, cellular metabolism, and villous vessel branching. Although several studies have described glycoconjugate distribution in the human placenta descriptions of their physiological function and control mechanisms during placental development are lacking. In this study we investigated the developmental distribution and regulation of placental core 1 O- and N-glycans focusing on early and late first trimester human pregnancy. To define the control mechanisms of the oligosaccharide chains during early placentation process, chorionic villous explants and human trophoblast cell lines were exposed to various oxygen levels. We found that oxygen tension regulates changes in core-1 O-glycan (the disaccharide Galβ1–3GalNAc) epitope expression levels. Moreover, by double affinity chromatography and subsequent analysis with mass spectrometry, we identified in the heat shock protein 90-α (HSP90α) a good candidate as carrier of the Galβ1–3GalNAc epitope at low oxygen tension. Our results support a fundamental role of oxygen tension in modulating glycosylation of proteins during placental development.

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108. FUNCTIONAL ROLE OF HtrA3 IN TROPHOBLAST CELL INVASION DURING HUMAN PLACENTAL DEVELOPMENT

Reproduction Fertility and Development ◽

10.1071/srb09abs108 ◽

2009 ◽

Vol 21 (9) ◽

pp. 27

Author(s):

H. Singh ◽

G. Nie

Keyword(s):

Cell Invasion ◽

Stromal Cells ◽

Functional Role ◽

First Trimester ◽

Trophoblast Cell ◽

Extravillous Trophoblast ◽

Placental Development ◽

Decidual Cells

Controlled invasion of extravillous trophoblast (EVT) through the maternal decidua is important for placental development and function. Serine protease HtrA3 is highly expressed in the decidual cells in the late secretory phase of the menstrual cycle and throughout pregnancy. It is highly expressed in first trimester in most trophoblast cell types, but not in the invading interstitial trophoblast. HtrA3 and its family members are down-regulated in a number of cancers and are proposed as tumor-suppressors. We hypothesized that HtrA3 is an inhibitor of trophoblast invasion and is down-regulated in invading EVTs, while up-regulation of decidual HtrA3 controls the process. The current study investigated HtrA3 expression in human endometrial stromal cells (HESC) during decidualization in vitro and whether HtrA3 inhibits EVT cell invasion. Stromal cells isolated from human endometrium were decidualized in vitro with estrogen, progesterone and cAMP. Quantitative RT-PCR and western showed HtrA3 mRNA and protein expression was significantly increased in decidualized HESC compared to controls. Indirect immunofluorescence showed homogeneous pattern and increase in intensity of HtrA3 staining in decidualized HESC compared to non-decidualized cells. HTR-8 cells derived from first trimester of pregnancy EVT showed higher levels of HtrA3 mRNA expression compared to other human choriocarcinoma cell lines (AC-1M88, AC-1M32, JEG-3 and BeWo). Both intracellular and extracellular HtrA3 staining was observed in HTR8 cells. Functional role of HtrA3 in cell invasion was determined in HTR-8 cells using an in vitro invasion assay. Exogenous addition of mutant HtrA3 (inhibitor) resulted in a significant increase in HTR-8 cells invading through matrigel coated membrane compared with controls. TGFβ-1 (as positive control) completely inhibited invasion of HTR-8 cells. HtrA3 is tightly regulated during decidualization of HESC in vitro. Inhibition of HtrA3 activity in trophoblastic HTR-8 cells increased invasiveness supporting its functional role during placental development.

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