scholarly journals Placental development during early pregnancy in sheep: cell proliferation, global methylation, and angiogenesis in the fetal placenta

Reproduction ◽  
2011 ◽  
Vol 141 (4) ◽  
pp. 529-540 ◽  
Author(s):  
Anna T Grazul-Bilska ◽  
Mary Lynn Johnson ◽  
Pawel P Borowicz ◽  
Megan Minten ◽  
Jerzy J Bilski ◽  
...  

To characterize early fetal placental development, gravid uterine tissues were collected from pregnant ewes every other day from day 16 to 30 after mating. Determination of 1) cell proliferation was based on Ki67 protein immunodetection; 2) global methylation was based on 5-methyl-cytosine (5mC) expression and mRNA expression for DNA methyltransferases (DNMTs)1,3a, and3b; and 3) vascular development was based on smooth muscle cell actin immunolocalization and on mRNA expression of several factors involved in the regulation of angiogenesis in fetal membranes (FMs). Throughout early pregnancy, the labeling index (proportion of proliferating cells) was very high (21%) and did not change. Expression of 5mC and mRNA forDNMT3bdecreased, but mRNA forDNMT1and3aincreased. Blood vessels were detected in FM on days 18–30 of pregnancy, and their number per tissue area did not change. The patterns of mRNA expression for placental growth factor, vascular endothelial growth factor, and their receptorsFLT1andKDR; angiopoietins 1 and 2 and their receptorTEK; endothelial nitric oxide synthase and the NO receptorGUCY13B; and hypoxia inducing factor 1 α changed in FM during early pregnancy. These data demonstrate high cellular proliferation rates, and changes in global methylation and mRNA expression of factors involved in the regulation of DNA methylation and angiogenesis in FM during early pregnancy. This description of cellular and molecular changes in FM during early pregnancy will provide the foundation for determining the basis of altered placental development in pregnancies compromised by environmental, genetic, or other factors.

Reproduction ◽  
2010 ◽  
Vol 140 (1) ◽  
pp. 165-174 ◽  
Author(s):  
Anna T Grazul-Bilska ◽  
Pawel P Borowicz ◽  
Mary Lynn Johnson ◽  
Megan A Minten ◽  
Jerzy J Bilski ◽  
...  

Placental vascular development (angiogenesis) is critical for placental function and thus for normal embryonic/fetal growth and development. Specific environmental factors or use of assisted reproductive techniques may result in poor placental angiogenesis, which may contribute to embryonic losses and/or fetal growth retardation. Uterine tissues were collected on days 14, 16, 18, 20, 22, 24, 26, 28, and 30 after mating and on day 10 after estrus (nonpregnant controls) to determine vascular development and expression of several factors involved in the regulation of angiogenesis in the endometrium. Compared with controls, several measurements of endometrial vascularity increased (P<0.001) including vascular labeling index (LI; proportion of proliferating cells), the tissue area occupied by capillaries, area per capillary (capillary size), total capillary circumference per unit of tissue area, and expression of factor VIII (marker of endothelial cells), but capillary number decreased (P<0.001). Compared with controls, mRNA for placental growth factor, vascular endothelial growth factor receptors, angiopoietins (ANGPT) 1 and 2, ANGPT receptorTEK, endothelial nitric oxide synthase, and hypoxia-inducible factor 1α increased (P<0.05) during early pregnancy. Vascular LI was positively correlated (P<0.05) with several measurements of vascularity and with mRNA expression of angiogenic factors. These data indicate that endometrial angiogenesis, manifested by increased vascularity and increased expression of several factors involved in the regulation of angiogenesis, is initiated very early in pregnancy. This more complete description of early placental angiogenesis may provide the foundation for determining whether placental vascular development is altered in compromised pregnancies.


2011 ◽  
Vol 23 (1) ◽  
pp. 161
Author(s):  
A. T. Grazul-Bilska ◽  
M. L. Johnson ◽  
P. P. Borowicz ◽  
D. A. Redmer ◽  
L. P. Reynolds

Normal placental development is critical for placental function and thus for normal embryonic and fetal growth and development. Many factors, including those from the environment or from the application of assisted reproductive techniques, are known to affect embryonic development. Additionally, altered DNA methylation was reported for fetal and/or maternal placenta from compromised pregnancies, and this may contribute to high embryonic/fetal loss. DNA methylation regulated by DNA methyltransferase (DNMT) plays an important role during embryonic development. However, little is known about the expression of DNMT in placental tissues during early pregnancy in any species. To determine the mRNA expression of DNMT 3a and 3b (developmentally-regulated DNMT) in normal placenta, caruncular (CAR, maternal placenta) tissue and fetal membranes (FM, chorioallantois or fetal placenta) were collected on Days 14, 16, 18, 20, 22, 24, 26, 28, and 30 after natural mating (n = 5–8 ewes day–1) and on Day 9–11 after oestrus (n = 7; non-pregnant [NP] controls, CAR only), snap-frozen, and then used for quantitative real time RT-PCR. For each tissue, data were analysed statistically by ANOVA with the day of pregnancy as the main effect. In CAR and FM, mRNA expression of DNMT3A and 3b was affected (P < 0.01–0.02) by day of pregnancy. In CAR, expression of DNMT3A was similar in NP controls and on days 14, 16, 18, and 30, was decreased (P < 0.01) ∼2-fold on day 20, and then gradually increased to day 30 of pregnancy. In CAR, expression of DNMT3b was similar in NP controls and on days 14, 16, 18, 24, 26, and 28, but was greater (P < 0.02) by ∼2-fold on days 22 and 30 than in NP controls or on days 24 and 26 of pregnancy. For CAR, regression analysis of DNMT3a mRNA expression demonstrated a cubic pattern (R2 = 0.253; P = 0.01) of expression during early pregnancy. In FM, DNMT3a increased (P < 0.01) ∼2-fold from day 16 to 24–30, but DNMT3b gradually decreased (∼0.5–5-fold; P < 0.01) from day 16 to day 30 of pregnancy. For FM, regression analysis of mRNA expression for DNMT3a demonstrated a linear increase (R2 = 0.301; P < 0.01), but for DNMT3b a cubic pattern (R2 = 0.624; P < 0.01) of expression during early pregnancy. These data indicate that DNMT3a and 3b mRNA are differentially expressed in CAR and FM, and the temporal pattern of expression of DNMT3a and 3b differs between maternal and fetal placental tissues during early pregnancy in sheep. Thus, significant changes in mRNA expression of DNMT3a and 3b in CAR and FM indicate that de novo methylation is present in the placenta during early pregnancy in sheep and may be regulated in part by the level of DNMT expression. These data provide a foundation for determining the basis for altered DNA methylation of placental and embryonic tissues in compromised pregnancies. Supported by USDA grant 2007-01215 to LPR and ATGB, and NIH grant HL64141 to LPR and DAR.


2013 ◽  
Vol 79 (1) ◽  
pp. 94-102 ◽  
Author(s):  
Anna T. Grazul-Bilska ◽  
Mary Lynn Johnson ◽  
Pawel P. Borowicz ◽  
Loren Baranko ◽  
Dale A. Redmer ◽  
...  

2009 ◽  
Vol 29 (23) ◽  
pp. 6309-6320 ◽  
Author(s):  
Sangphil Oh ◽  
Dongjun Lee ◽  
Tackhoon Kim ◽  
Tae-Shin Kim ◽  
Hyun Jung Oh ◽  
...  

ABSTRACT Mammalian sterile 20-like kinases 1 and 2 (Mst1 and Mst2, respectively) are potent serine/threonine kinases that are involved in cell proliferation and cell death. To investigate the physiological functions of Mst1 and Mst2, we generated Mst1 and Mst2 mutant mice. Mst1 −/− and Mst2 −/− mice were viable and fertile and developed normally, suggesting possible functional overlaps between the two genes. A characterization of heterozygous and homozygous combinations of Mst1 and Mst2 mutant mice showed that mice containing a single copy of either gene underwent normal organ development; however, Mst1 −/−; Mst2 −/− mice lacking both Mst1 and Mst2 genes started dying in utero at approximately embryonic day 8.5. Mst1 −/−; Mst2 −/− mice exhibited severe growth retardation, failed placental development, impaired yolk sac/embryo vascular patterning and primitive hematopoiesis, increased apoptosis in placentas and embryos, and disorganized proliferating cells in the embryo proper. These findings indicate that both Mst1 and Mst2 kinases play essential roles in early mouse development, regulating placental development, vascular patterning, primitive hematopoiesis, and cell proliferation and survival.


2000 ◽  
Vol 68 (11) ◽  
pp. 6505-6508 ◽  
Author(s):  
K. A. Wilkinson ◽  
T. D. Martin ◽  
S. M. Reba ◽  
H. Aung ◽  
R. W. Redline ◽  
...  

ABSTRACT Latency-associated peptide of transforming growth factor β (TGF-β) (LAP) was used to determine whether in vivo modulation of TGF-β bioactivity enhanced pulmonary immunity to Mycobacterium bovis BCG infection in C57BL/6 mice. LAP decreased BCG growth in the lung and enhanced antigen-specific T-cell proliferation and gamma interferon mRNA expression. Thus, susceptibility of the lung to primary BCG infection may be partially mediated by the immunosuppressive effects of TGF-β.


2020 ◽  
Vol 27 (5) ◽  
pp. 411-418 ◽  
Author(s):  
Meiyu Qiu ◽  
Tao Li ◽  
Binhu Wang ◽  
Hongbin Gong ◽  
Tao Huang

Background: microRNAs (miRNAs) are a small, endogenous non-coding RNAs that are involved in post-transcriptional gene regulation of many biological processes, including embryo implantation and placental development. In our previous study, miR-146a-5p was found expressed higher in the serum exosomes of pregnant sows than non-pregnant. The research on miR-146a-5p has been mainly related to human diseases, but there are few studies on its effects on the reproduction of sows in early pregnancy. Objective: In this article, our motivation is to study the role of miR-146a-5p in the early pregnancy of sows on the cell proliferetion and apoptosis by targeting SMAD3 and SMAD4. Methods: Bioinformatics software was used to identify the target genes of miR-146a-5p. The wildtype and mutant-type recombinant plasmids of dual-luciferase reporter with 3'-UTR of Smad3 or 3'- UTR of Smad4 were constructed, and co-transfected in porcine kidney cell (PK-15 cell) with miR- 146a-5p mimic, mimic-NC(M-NC), inhibitor and inhibitor-NC(IN-NC), then dual-luciferase activity analysis, qRT-PCR and Western blot were performed to verify the target genes. After the transfection of BeWo choriocarcinoma cell (BeWo cell) with miR-146a-5p mimic, M-NC, inhibitor and IN-NC, the mRNA expression of Caspase-3, BAX and Bcl-2 was measured using qRT-PCR, and the cell proliferation was measured using CCK-8 kit. Results: The luciferase, mRNA and protein expression of Smad3 in PK-15 cells treated by Smad3- 3'-UTR-W co-transfected with miR-146a-5p mimic were significantly lower than that with miR- 146a-5p M-NC, and the results of Smad4 were similar to Smad3, but the protein expression had a trend to lower in mimic group. The expression level of Bcl-2 in the miR-146a-5p mimic group was significantly lower than that in the miR-146a-5p M-NC group, but the expression pattern of Caspase-3 was just opposite. The mimic of miR-146a-5p reduced the proliferation of BeWo cells, however the inhibitor increased. Conclusion: Smad3 and Smad4 are the direct target genes of miR-146a-5p. The expression of Smad3 and Smad4 were affected by the mimic and inhibitor of miR-146a-5p. miR-146a-5p affects cell apoptosis and proliferation by regulating their target genes. This study provided new data to understand the regulation mechanism of early pregnancy in sows.


Reproduction ◽  
2000 ◽  
pp. 407-416 ◽  
Author(s):  
TS Gadd ◽  
RP Aitken ◽  
JM Wallace ◽  
DC Wathes

The aim of the present study was to investigate the effects of administering a high plane diet during early to mid-gestation on the uterine and placental insulin-like growth factor (IGF) system and on systemic IGF-I concentrations in pregnant adolescent ewes with restricted placental growth. Embryos recovered from superovulated ewes inseminated by a single sire were transferred in singleton to the uterus of adolescent recipients. After transfer ewes were offered a high (H) or moderate (M) amount of a complete diet calculated to promote rapid or normal maternal growth rates, respectively. Five ewes from each group were switched from either M to H or H to M diets at day 52 of gestation. Maternal and fetal blood samples and placental tissues were collected from all animals at day 104. Ewes on the high plane diet from mid-gestation (HH, MH groups) had restricted placental mass (P < 0.01) and tended to have smaller fetuses. This was associated with increased maternal plasma IGF-I concentrations (P < 0.001). The pattern of expression of components of the IGF system in the uterus and placenta was studied by in situ hybridization. IGF-I mRNA concentrations were below the limit of detection. IGF-II mRNA expression was high in the fetal mesoderm and present in maternal stroma, but was not influenced by nutritional treatment. In contrast, IGF binding protein 1 (IGFBP-1) mRNA expression was higher (P < 0.05) and IGFBP-3 mRNA expression was lower (P < 0.05) in the endometrial glands of ewes in HH and MH groups. In the fetal trophoblast, IGFBP-3 mRNA expression was higher in the MH group. Type 1 IGF receptor expression was increased (P < 0. 01) in the luminal epithelium of the HM group and IGFBP-2 mRNA expression was highest in the placentome capsule of ewes in the HH group. Together, these results indicate that reprogramming of the uterine and placental IGF axis by maternal nutrition could contribute to placental growth retardation in growing adolescent sheep.


1994 ◽  
Vol 6 (4) ◽  
pp. 453-457 ◽  
Author(s):  
Alain Pierre Théon ◽  
Loretta Metzger ◽  
Stephen Griffey

Cell proliferation in canine, feline, and equine tumors was evaluated using immunohistochemical detection of in vitro 5–bromodeoxyuridine (BrdU) incorporation, proliferating cell nuclear antigen (PCNA), and interchromatin-associated antigen (p105). Ten tumors in each species were analyzed. The tumor proliferative fraction (PF) was defined as the percentage of labeled nuclei for 5,000 tumor nuclei counted. Immunoreactivity was observed with all techniques in all species. A good correlation was observed between the proliferative fractions measured with the BrdU (PFBrdU) and PCNA (PFPCNA) techniques ( rs = 0.523, P = 0.0026). There was no correlation between the PFs measured with the BrdU (PFBrdU) and p105 (PFP105) techniques. Using the median values obtained from the different approaches as cutoff points to define slowly and rapidly proliferating tumors, there was an 80% agreement ( P = 0.009) between PFBrdU and PFPCNA and no agreement between PFBrdU and PFP105 The results of this study indicate that both BrdU and PCNA labeling methods can be used reliably for identifying proliferating cells in animal tumors. In addition, PCNA could be used to replace the BrdU method to assess tumor proliferative fraction because it does not require pretreatment of tissues.


1998 ◽  
Vol 18 (12) ◽  
pp. 7487-7498 ◽  
Author(s):  
Sheng Wang ◽  
Richik N. Ghosh ◽  
Srikumar P. Chellappan

ABSTRACT Cells initiate proliferation in response to growth factor stimulation, but the biochemical mechanisms linking signals received at the cell surface receptors to the cell cycle regulatory molecules are not yet clear. In this study, we show that the signaling molecule Raf-1 can physically interact with Rb and p130 proteins in vitro and in vivo and that this interaction can be detected in mammalian cells without overexpressing any component. The binding of Raf-1 to Rb occurs subsequent to mitogen stimulation, and this interaction can be detected only in proliferating cells. Raf-1 can inactivate Rb function and can reverse Rb-mediated repression of E2F1 transcription and cell proliferation efficiently. The region of Raf-1 involved in Rb binding spanned residues 1 to 28 at the N terminus, and functional inactivation of Rb required a direct interaction. Serum stimulation of quiescent human fibroblast HSF8 cells led to a partial translocation of Raf-1 into the nucleus, where it colocalized with Rb. Further, Raf-1 was able to phosphorylate Rb in vitro quite efficiently. We believe that the physical interaction of Raf-1 with Rb is a vital step in the growth factor-mediated induction of cell proliferation and that Raf-1 acts as a direct link between cell surface signaling cascades and the cell cycle machinery.


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