Olga Genbacev - Academia.edu (original) (raw)
Papers by Olga Genbacev
Development, 2015
Mechanisms of initial cell fate decisions differ among species. To gain insights into lineage all... more Mechanisms of initial cell fate decisions differ among species. To gain insights into lineage allocation in humans, we derived ten human embryonic stem cell lines from single blastomeres of four 8-cell embryos and one 12-cell embryo from a single couple (UCSFB1-10). Versus numerous conventional lines from blastocysts, they had unique gene expression and DNA methylation patterns, in part, indicative of trophoblast competence. At a transcriptional level, UCSFB lines from different embryos were often more closely related than those from the same embryo. As predicted by the transcriptomic data, immunolocalization of EOMES, BRACHYURY, GDF15 and active β-catenin revealed differential expression among blastomeres of 8-10-cell human embryos. The UCSFB lines formed derivatives of the three germ layers and CDX2-positive progeny, from which we derived the first human trophoblast stem cell line. Our data suggest heterogeneity among early-stage blastomeres and that the UCSFB lines have unique properties, indicative of a more immature state than conventional lines.
Placenta, 2000
... 4 M Castellucci, I Classen-Linke, J Muhlhauser, P Kaufmann, L Zardi and R Chiquet-Ehrismann, ... more ... 4 M Castellucci, I Classen-Linke, J Muhlhauser, P Kaufmann, L Zardi and R Chiquet-Ehrismann, The human placenta: A model for ... 319. 19 F Rodesch, P Simon, C Donner and E Jauniaux, Oxygen measurements in endometrial and trophoblastic tissue during early pregnancy. ...
Regenerative Medicine, 2006
Reproductive Medicine and Assisted Reproductive Techniques, 2009
Cancer and Pregnancy, 2001
Placenta, 2005
Studies of placental pathologies associated with maternal cigarette smoking have led to many inte... more Studies of placental pathologies associated with maternal cigarette smoking have led to many interesting observations. For example, maternal smoking impairs human placental development by changing the balance between cytotrophoblast (CTB) proliferation and differentiation. It is likely that chronic exposure to tobacco constituents in early pregnancy can affect placental development directly or indirectly by reducing blood flow, which creates a pathologically hypoxic environment. To understand this process at a molecular level, tissue samples from non-smoking and smoking mothers were studied to determine whether active and/or passive cigarette smoke exposure affects CTB expression of molecules that govern cellular responses to oxygen tension: the von Hippel-Lindau tumor suppressor protein (pVHL), hypoxia-inducible transcription factors (HIFs) and vascular endothelial growth factor-A (VEGF). The results show that maternal smoking dysregulates CTB expression of all three types of molecules. In addition, cell columns and proliferating cells were reduced while there was a corresponding increase in cell islands. All three phenomena were most obvious in the placentas of heavy smokers. Interestingly, a subset of the aforementioned effects can be detected in samples obtained from women who were passively exposed to cigarette smoke during pregnancy. These observations suggest that tobacco constituents exert direct effects on CTB proliferation and differentiation and help to explain the mechanisms by which smoking negatively effects human pregnancy outcome.
Placenta, 1992
The described villous tissue culture system may be, therefore, a unique in vitro model to study p... more The described villous tissue culture system may be, therefore, a unique in vitro model to study prolsferation and dajerentiation of EVT from cytotrophoblastic columns, the regulation ofEV"Tproltferation and dt~erentiation, the role ofECM in the induction of the migration and the interaction of extravillous and villous trophoblast at the level of the cytotrophoblastic column.
The American Journal of Pathology, 1999
Preeclampsia is a serious pregnancy complication diagnosed by signs of widespread maternal endoth... more Preeclampsia is a serious pregnancy complication diagnosed by signs of widespread maternal endothelial dysfunction. In normal pregnancy , a subpopulation of placental cytotrophoblast stem cells executes an unusual differentiation program that leads to invasion of the uterus and its vasculature. This process attaches the conceptus to the uterine wall and starts the flow of maternal blood to the placenta. Preeclampsia is associated with abnormal cytotrophoblast differentiation , shallow invasion , and decreased blood flow to the placenta. To determine whether abnormal differentiation and/or hypoxia leads to cytotrophoblast apoptosis , we used the TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) method to label DNA strand breaks in tissue sections of the placenta and the uterine wall to which it attaches. Control samples (n ؍ 9) showed almost no apoptosis , but in samples from patients with preeclampsia , 15-50% of the cytotrophoblasts that invaded the uterine wall were labeled (8/9 samples). These same cells failed to stain for Bcl-2, a survival factor normally expressed by trophoblasts in both the placenta and the uterine wall. Our results show that preeclampsia is associated with widespread apoptosis of cytotrophoblasts that invade the uterus. The magnitude of programmed cell death in this population may account for the sudden onset of symptoms in some patients , as well as the associated coagulopathies. The preeclampsia syndrome affects approximately 7% of nulliparous women. 1 The mother shows signs and symptoms that suggest widespread alterations in endothelial function (eg, high blood pressure, proteinuria, and edema). 2 In some cases the fetus stops growing, which leads to intrauterine growth retardation. The dangers of this condition are exacerbated by the fact that the maternal and fetal signs can suddenly appear at any time from mid-second trimester until term-hence the name preeclampsia (from Greek eklampsis, sudden flash or development).
Journal of Tissue Viability, 1994
Life Sciences, Feb 1, 1988
Opiate synthesis by human placental cells and the presence of kappa-type opiate binding sites in ... more Opiate synthesis by human placental cells and the presence of kappa-type opiate binding sites in the syncytiotrophoblast brush border membrane may indicate the possible role of morphine-like substances in the autocrine regulation of trophoblast cell metabolism. This study was undertaken to examine the in vitro effect of morphine on hCG (human chorionic gonadotrophin) and hPL (human placental lactogen) release by 1st and 3rd trimester placental tissue explants. The results have shown that morphine (100 nM) significantly stimulated hCG secretion by 6-8 weeks old trophoblast and was without effect on hPL. Hormone secretion by term placental tissue explants was unaffected by morphine treatment. Based on these results we assume that opiates may have a role in the local (autocrine and/or paracrine) regulation of hCG secretion in early gestation.
Regenerative Medicine, 2011
Reproductive Toxicology, 1995
Differentiation of the specialized epitbelhd cells of the placenta, termed cytotrophoblasts, is a... more Differentiation of the specialized epitbelhd cells of the placenta, termed cytotrophoblasts, is a particularly important aspect of placental development during the first trimester of pregnancy. During this process cytotrophoblast stem cells either fuse to form the syncytium or aggregate to form cell columns that adhere to, then invade the uterus. We found that choriouic villi from early gestation placentas of mothers who smoke showed a marked reduction in cell columns, a defect that could not be corrected by placing them in culture. We used two different in vitro models to determine if nicotine plays a role in the etiology of this defect. Exposing early gestation chorionic villi from nonsmoking women to nicotine inhibited subsequent cell column formation in vitro. Nicotine also inhibited normal tlrst trimester cytotrophoblast invasion, apparently by reducing the ability of treated cells to synthesize and activate the 92 kDa type IV couagenase, an important mediator of invasion in vitro. These results suggest that maternal cigarette smoking inhibits the trophoblast differentiation pathway that leads to column formation and uterine invasion. This effect, which is due at least in part to the effects of nicotine, may contribute to the growth retardation observed in fetuses of mothers who smoke during prepancy.
Placenta, 2005
Placental explant cultures in vitro are useful for studying tissue functions including cellular u... more Placental explant cultures in vitro are useful for studying tissue functions including cellular uptake, production and release of secretory components, cell interactions, proliferation, growth and differentiation, gene delivery, pharmacology, toxicology, and disease processes. A variety of culture conditions are required to mimic in utero environments at different times of gestation including differing oxygen partial pressures, extracellular matrices and culture medium. Optimization of explant methods is examined for first and third trimester human placental tissue and the biological processes under investigation.
Journal of Virology, 2007
Cytomegalovirus (CMV), the major viral cause of congenital disease, infects the uterus and develo... more Cytomegalovirus (CMV), the major viral cause of congenital disease, infects the uterus and developing placenta and spreads to the fetus throughout gestation. Virus replicates in invasive cytotrophoblasts in the decidua, and maternal immunoglobulin G (IgG)-CMV virion complexes, which are transcytosed by the neonatal Fc receptor across syncytiotrophoblasts, infect underlying cytotrophoblasts in chorionic villi. Immunity is central to protection of the placenta-fetal unit: infection can occur when IgG has a low neutralizing titer. Here we used immunohistochemical and function-blocking methods to correlate infection in the placenta with expression of potential CMV receptors in situ and in vitro.
Developmental Biology, 2006
Cytotrophoblast (CTB) aggregates that bridge the gap between the placenta and the uterus are susp... more Cytotrophoblast (CTB) aggregates that bridge the gap between the placenta and the uterus are suspended as cell columns in the intervillous space, where they experience significant amounts of shear stress generated by maternal blood flow. The proper formation of these structures is crucial to pregnancy outcome as they play a vital role in anchoring the embryo/fetus to the decidua. At the same time, they provide a route by which CTBs enter the uterine wall. The mechanism by which the integrity of the columns is maintained while allowing cell movement is unknown. Here, we present evidence that the interactions of L-selectin with its carbohydrate ligands, a specialized adhesion system that is activated by shear stress, play an important role. CTBs in cell columns, particularly near the distal ends, stained brightly for L-selectin and with the TRA-1-81 antibody, which recognizes carbohydrate epitopes that support binding of L-selectin chimeras in vitro. Function-perturbing antibodies that inhibited either receptor or ligand activity also inhibited formation of cell columns in vitro. Together, these results suggest an autocrine role for the CTB L-selectin adhesion system in forming and maintaining cell columns during the early stages of placental development, when the architecture of the basal plate region is established. This type of adhesion may also facilitate CTB exit from cell columns, a prerequisite for uterine invasion.
American Journal of Obstetrics and Gynecology, 2001
Our goal was to test the hypothesis that cytotrophoblasts, under low oxygen tension, release subs... more Our goal was to test the hypothesis that cytotrophoblasts, under low oxygen tension, release substances that affect vascular behavior. We studied the vascular response to the vasoconstrictors phenylephrine (receptor dependent) and potassium (receptor independent), the relaxation response to methacholine, and the vasomotor behavior of isolated resistance (mesenteric) arteries from early pregnant rats after incubation in conditioned medium from first-trimester cytotrophoblasts, maintained in standard or hypoxic (2%; 14 mm Hg) culture conditions. After incubation in medium from hypoxic cytotrophoblasts, arterial segments were more responsive to phenylephrine and to potassium-induced constriction but were less responsive to methacholine, and the vasomotor activity was increased compared with that found in vessels incubated in control medium. These changes in vascular behavior are similar to those reported in isolated arteries from women with preeclampsia. These studies provide evidence which suggests that the link between abnormal placentation and maternal vascular abnormality in preeclampsia is the elaboration of vasoactive factors by cytotrophoblasts in response to hypoxia.
American Journal of Obstetrics and Gynecology, 2011
Development, 2015
Mechanisms of initial cell fate decisions differ among species. To gain insights into lineage all... more Mechanisms of initial cell fate decisions differ among species. To gain insights into lineage allocation in humans, we derived ten human embryonic stem cell lines from single blastomeres of four 8-cell embryos and one 12-cell embryo from a single couple (UCSFB1-10). Versus numerous conventional lines from blastocysts, they had unique gene expression and DNA methylation patterns, in part, indicative of trophoblast competence. At a transcriptional level, UCSFB lines from different embryos were often more closely related than those from the same embryo. As predicted by the transcriptomic data, immunolocalization of EOMES, BRACHYURY, GDF15 and active β-catenin revealed differential expression among blastomeres of 8-10-cell human embryos. The UCSFB lines formed derivatives of the three germ layers and CDX2-positive progeny, from which we derived the first human trophoblast stem cell line. Our data suggest heterogeneity among early-stage blastomeres and that the UCSFB lines have unique properties, indicative of a more immature state than conventional lines.
Placenta, 2000
... 4 M Castellucci, I Classen-Linke, J Muhlhauser, P Kaufmann, L Zardi and R Chiquet-Ehrismann, ... more ... 4 M Castellucci, I Classen-Linke, J Muhlhauser, P Kaufmann, L Zardi and R Chiquet-Ehrismann, The human placenta: A model for ... 319. 19 F Rodesch, P Simon, C Donner and E Jauniaux, Oxygen measurements in endometrial and trophoblastic tissue during early pregnancy. ...
Regenerative Medicine, 2006
Reproductive Medicine and Assisted Reproductive Techniques, 2009
Cancer and Pregnancy, 2001
Placenta, 2005
Studies of placental pathologies associated with maternal cigarette smoking have led to many inte... more Studies of placental pathologies associated with maternal cigarette smoking have led to many interesting observations. For example, maternal smoking impairs human placental development by changing the balance between cytotrophoblast (CTB) proliferation and differentiation. It is likely that chronic exposure to tobacco constituents in early pregnancy can affect placental development directly or indirectly by reducing blood flow, which creates a pathologically hypoxic environment. To understand this process at a molecular level, tissue samples from non-smoking and smoking mothers were studied to determine whether active and/or passive cigarette smoke exposure affects CTB expression of molecules that govern cellular responses to oxygen tension: the von Hippel-Lindau tumor suppressor protein (pVHL), hypoxia-inducible transcription factors (HIFs) and vascular endothelial growth factor-A (VEGF). The results show that maternal smoking dysregulates CTB expression of all three types of molecules. In addition, cell columns and proliferating cells were reduced while there was a corresponding increase in cell islands. All three phenomena were most obvious in the placentas of heavy smokers. Interestingly, a subset of the aforementioned effects can be detected in samples obtained from women who were passively exposed to cigarette smoke during pregnancy. These observations suggest that tobacco constituents exert direct effects on CTB proliferation and differentiation and help to explain the mechanisms by which smoking negatively effects human pregnancy outcome.
Placenta, 1992
The described villous tissue culture system may be, therefore, a unique in vitro model to study p... more The described villous tissue culture system may be, therefore, a unique in vitro model to study prolsferation and dajerentiation of EVT from cytotrophoblastic columns, the regulation ofEV"Tproltferation and dt~erentiation, the role ofECM in the induction of the migration and the interaction of extravillous and villous trophoblast at the level of the cytotrophoblastic column.
The American Journal of Pathology, 1999
Preeclampsia is a serious pregnancy complication diagnosed by signs of widespread maternal endoth... more Preeclampsia is a serious pregnancy complication diagnosed by signs of widespread maternal endothelial dysfunction. In normal pregnancy , a subpopulation of placental cytotrophoblast stem cells executes an unusual differentiation program that leads to invasion of the uterus and its vasculature. This process attaches the conceptus to the uterine wall and starts the flow of maternal blood to the placenta. Preeclampsia is associated with abnormal cytotrophoblast differentiation , shallow invasion , and decreased blood flow to the placenta. To determine whether abnormal differentiation and/or hypoxia leads to cytotrophoblast apoptosis , we used the TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) method to label DNA strand breaks in tissue sections of the placenta and the uterine wall to which it attaches. Control samples (n ؍ 9) showed almost no apoptosis , but in samples from patients with preeclampsia , 15-50% of the cytotrophoblasts that invaded the uterine wall were labeled (8/9 samples). These same cells failed to stain for Bcl-2, a survival factor normally expressed by trophoblasts in both the placenta and the uterine wall. Our results show that preeclampsia is associated with widespread apoptosis of cytotrophoblasts that invade the uterus. The magnitude of programmed cell death in this population may account for the sudden onset of symptoms in some patients , as well as the associated coagulopathies. The preeclampsia syndrome affects approximately 7% of nulliparous women. 1 The mother shows signs and symptoms that suggest widespread alterations in endothelial function (eg, high blood pressure, proteinuria, and edema). 2 In some cases the fetus stops growing, which leads to intrauterine growth retardation. The dangers of this condition are exacerbated by the fact that the maternal and fetal signs can suddenly appear at any time from mid-second trimester until term-hence the name preeclampsia (from Greek eklampsis, sudden flash or development).
Journal of Tissue Viability, 1994
Life Sciences, Feb 1, 1988
Opiate synthesis by human placental cells and the presence of kappa-type opiate binding sites in ... more Opiate synthesis by human placental cells and the presence of kappa-type opiate binding sites in the syncytiotrophoblast brush border membrane may indicate the possible role of morphine-like substances in the autocrine regulation of trophoblast cell metabolism. This study was undertaken to examine the in vitro effect of morphine on hCG (human chorionic gonadotrophin) and hPL (human placental lactogen) release by 1st and 3rd trimester placental tissue explants. The results have shown that morphine (100 nM) significantly stimulated hCG secretion by 6-8 weeks old trophoblast and was without effect on hPL. Hormone secretion by term placental tissue explants was unaffected by morphine treatment. Based on these results we assume that opiates may have a role in the local (autocrine and/or paracrine) regulation of hCG secretion in early gestation.
Regenerative Medicine, 2011
Reproductive Toxicology, 1995
Differentiation of the specialized epitbelhd cells of the placenta, termed cytotrophoblasts, is a... more Differentiation of the specialized epitbelhd cells of the placenta, termed cytotrophoblasts, is a particularly important aspect of placental development during the first trimester of pregnancy. During this process cytotrophoblast stem cells either fuse to form the syncytium or aggregate to form cell columns that adhere to, then invade the uterus. We found that choriouic villi from early gestation placentas of mothers who smoke showed a marked reduction in cell columns, a defect that could not be corrected by placing them in culture. We used two different in vitro models to determine if nicotine plays a role in the etiology of this defect. Exposing early gestation chorionic villi from nonsmoking women to nicotine inhibited subsequent cell column formation in vitro. Nicotine also inhibited normal tlrst trimester cytotrophoblast invasion, apparently by reducing the ability of treated cells to synthesize and activate the 92 kDa type IV couagenase, an important mediator of invasion in vitro. These results suggest that maternal cigarette smoking inhibits the trophoblast differentiation pathway that leads to column formation and uterine invasion. This effect, which is due at least in part to the effects of nicotine, may contribute to the growth retardation observed in fetuses of mothers who smoke during prepancy.
Placenta, 2005
Placental explant cultures in vitro are useful for studying tissue functions including cellular u... more Placental explant cultures in vitro are useful for studying tissue functions including cellular uptake, production and release of secretory components, cell interactions, proliferation, growth and differentiation, gene delivery, pharmacology, toxicology, and disease processes. A variety of culture conditions are required to mimic in utero environments at different times of gestation including differing oxygen partial pressures, extracellular matrices and culture medium. Optimization of explant methods is examined for first and third trimester human placental tissue and the biological processes under investigation.
Journal of Virology, 2007
Cytomegalovirus (CMV), the major viral cause of congenital disease, infects the uterus and develo... more Cytomegalovirus (CMV), the major viral cause of congenital disease, infects the uterus and developing placenta and spreads to the fetus throughout gestation. Virus replicates in invasive cytotrophoblasts in the decidua, and maternal immunoglobulin G (IgG)-CMV virion complexes, which are transcytosed by the neonatal Fc receptor across syncytiotrophoblasts, infect underlying cytotrophoblasts in chorionic villi. Immunity is central to protection of the placenta-fetal unit: infection can occur when IgG has a low neutralizing titer. Here we used immunohistochemical and function-blocking methods to correlate infection in the placenta with expression of potential CMV receptors in situ and in vitro.
Developmental Biology, 2006
Cytotrophoblast (CTB) aggregates that bridge the gap between the placenta and the uterus are susp... more Cytotrophoblast (CTB) aggregates that bridge the gap between the placenta and the uterus are suspended as cell columns in the intervillous space, where they experience significant amounts of shear stress generated by maternal blood flow. The proper formation of these structures is crucial to pregnancy outcome as they play a vital role in anchoring the embryo/fetus to the decidua. At the same time, they provide a route by which CTBs enter the uterine wall. The mechanism by which the integrity of the columns is maintained while allowing cell movement is unknown. Here, we present evidence that the interactions of L-selectin with its carbohydrate ligands, a specialized adhesion system that is activated by shear stress, play an important role. CTBs in cell columns, particularly near the distal ends, stained brightly for L-selectin and with the TRA-1-81 antibody, which recognizes carbohydrate epitopes that support binding of L-selectin chimeras in vitro. Function-perturbing antibodies that inhibited either receptor or ligand activity also inhibited formation of cell columns in vitro. Together, these results suggest an autocrine role for the CTB L-selectin adhesion system in forming and maintaining cell columns during the early stages of placental development, when the architecture of the basal plate region is established. This type of adhesion may also facilitate CTB exit from cell columns, a prerequisite for uterine invasion.
American Journal of Obstetrics and Gynecology, 2001
Our goal was to test the hypothesis that cytotrophoblasts, under low oxygen tension, release subs... more Our goal was to test the hypothesis that cytotrophoblasts, under low oxygen tension, release substances that affect vascular behavior. We studied the vascular response to the vasoconstrictors phenylephrine (receptor dependent) and potassium (receptor independent), the relaxation response to methacholine, and the vasomotor behavior of isolated resistance (mesenteric) arteries from early pregnant rats after incubation in conditioned medium from first-trimester cytotrophoblasts, maintained in standard or hypoxic (2%; 14 mm Hg) culture conditions. After incubation in medium from hypoxic cytotrophoblasts, arterial segments were more responsive to phenylephrine and to potassium-induced constriction but were less responsive to methacholine, and the vasomotor activity was increased compared with that found in vessels incubated in control medium. These changes in vascular behavior are similar to those reported in isolated arteries from women with preeclampsia. These studies provide evidence which suggests that the link between abnormal placentation and maternal vascular abnormality in preeclampsia is the elaboration of vasoactive factors by cytotrophoblasts in response to hypoxia.
American Journal of Obstetrics and Gynecology, 2011