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Derisoud E, Jouneau L, Dubois C, Archilla C, Jaszczyszyn Y, Legendre R, Daniel N, Peynot N, Dahirel M, Auclair-Ronzaud J, Wimel L, Duranthon V, Chavatte-Palmer P. Maternal age affects equine day 8 embryo gene expression both in trophoblast and inner cell mass. BMC Genomics 2022; 23:443. [PMID: 35705916 PMCID: PMC9199136 DOI: 10.1186/s12864-022-08593-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 04/22/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Breeding a mare until she is not fertile or even until her death is common in equine industry but the fertility decreases as the mare age increases. Embryo loss due to reduced embryo quality is partly accountable for this observation. Here, the effect of mare's age on blastocysts' gene expression was explored. Day 8 post-ovulation embryos were collected from multiparous young (YM, 6-year-old, N = 5) and older (OM, > 10-year-old, N = 6) non-nursing Saddlebred mares, inseminated with the semen of one stallion. Pure or inner cell mass (ICM) enriched trophoblast, obtained by embryo bisection, were RNA sequenced. Deconvolution algorithm was used to discriminate gene expression in the ICM from that in the trophoblast. Differential expression was analyzed with embryo sex and diameter as cofactors. Functional annotation and classification of differentially expressed genes and gene set enrichment analysis were also performed. RESULTS Maternal aging did not affect embryo recovery rate, embryo diameter nor total RNA quantity. In both compartments, the expression of genes involved in mitochondria and protein metabolism were disturbed by maternal age, although more genes were affected in the ICM. Mitosis, signaling and adhesion pathways and embryo development were decreased in the ICM of embryos from old mares. In trophoblast, ion movement pathways were affected. CONCLUSIONS This is the first study showing that maternal age affects gene expression in the equine blastocyst, demonstrating significant effects as early as 10 years of age. These perturbations may affect further embryo development and contribute to decreased fertility due to aging.
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Affiliation(s)
- Emilie Derisoud
- Université Paris-Saclay, UVSQ, INRAE, BREED, 78350, Jouy-en-Josas, France.
- Ecole Nationale Vétérinaire d'Alfort, BREED, 94700, Maisons-Alfort, France.
| | - Luc Jouneau
- Université Paris-Saclay, UVSQ, INRAE, BREED, 78350, Jouy-en-Josas, France
- Ecole Nationale Vétérinaire d'Alfort, BREED, 94700, Maisons-Alfort, France
| | - Cédric Dubois
- IFCE, Plateau technique de Chamberet, 19370, Chamberet, France
| | - Catherine Archilla
- Université Paris-Saclay, UVSQ, INRAE, BREED, 78350, Jouy-en-Josas, France
- Ecole Nationale Vétérinaire d'Alfort, BREED, 94700, Maisons-Alfort, France
| | - Yan Jaszczyszyn
- Institute for Integrative Biology of the Cell (I2BC), UMR 9198 CNRS, CEA, Paris-Sud University F-91198, Gif-sur-Yvette, France
| | - Rachel Legendre
- Institut Pasteur-Bioinformatics and Biostatistics Hub-Department of Computational Biology, Paris, France
| | - Nathalie Daniel
- Université Paris-Saclay, UVSQ, INRAE, BREED, 78350, Jouy-en-Josas, France
- Ecole Nationale Vétérinaire d'Alfort, BREED, 94700, Maisons-Alfort, France
| | - Nathalie Peynot
- Université Paris-Saclay, UVSQ, INRAE, BREED, 78350, Jouy-en-Josas, France
- Ecole Nationale Vétérinaire d'Alfort, BREED, 94700, Maisons-Alfort, France
| | - Michèle Dahirel
- Université Paris-Saclay, UVSQ, INRAE, BREED, 78350, Jouy-en-Josas, France
- Ecole Nationale Vétérinaire d'Alfort, BREED, 94700, Maisons-Alfort, France
| | | | - Laurence Wimel
- IFCE, Plateau technique de Chamberet, 19370, Chamberet, France
| | - Véronique Duranthon
- Université Paris-Saclay, UVSQ, INRAE, BREED, 78350, Jouy-en-Josas, France
- Ecole Nationale Vétérinaire d'Alfort, BREED, 94700, Maisons-Alfort, France
| | - Pascale Chavatte-Palmer
- Université Paris-Saclay, UVSQ, INRAE, BREED, 78350, Jouy-en-Josas, France.
- Ecole Nationale Vétérinaire d'Alfort, BREED, 94700, Maisons-Alfort, France.
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Epigenetic Changes in Equine Embryos after Short-Term Storage at Different Temperatures. Animals (Basel) 2021; 11:ani11051325. [PMID: 34066466 PMCID: PMC8148113 DOI: 10.3390/ani11051325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/10/2021] [Accepted: 05/03/2021] [Indexed: 11/17/2022] Open
Abstract
Simple Summary In embryos subjected to assisted reproductive techniques, epigenetic modifications may occur that can influence embryonic development and establishment of pregnancy. In horses, the storage temperature during transport of fresh embryos before transfer is a major concern. The aim of this study was, therefore, to determine the effects of two storage temperatures (5 °C and 20 °C) on equine embryos, collected at day seven after ovulation and stored for 24 h, concerning morphological development, expression of candidate genes associated with embryo growth and development, maternal recognition of pregnancy, methylation, apoptosis and gene-specific and global DNA methylation. Temperature during storage did not affect embryo size. There were no changes in pH and lipid peroxidation of the medium irrespective of group. mRNA expression and gene-specific DNA methylation of genes related to growth and development, maternal recognition of pregnancy, DNA methylation and apoptosis in stored embryos (5 °C and 20 °C) were altered when compared to fresh embryos. Therefore, our study demonstrates for the first time the gene-specific and global DNA methylation status of fresh equine embryos collected on days seven and eight after ovulation. Short-term storage, regardless of temperature, may compromise embryo development after transfer. Abstract In embryos subjected to assisted reproductive techniques, epigenetic modifications may occur that can influence embryonic development and the establishment of pregnancy. In horses, the storage temperature during transport of fresh embryos before transfer is a major concern. The aim of this study was, therefore, to determine the effects of two storage temperatures (5 °C and 20 °C) on equine embryos, collected at day seven after ovulation and stored for 24 h, on: (i) morphological development; (ii) expression of candidate genes associated with embryo growth and development, maternal recognition of pregnancy, methylation and apoptosis, and (iii) gene-specific and global DNA methylation. Embryos (n = 80) were collected on day seven or day eight after ovulation and assigned to four groups: day seven control (E7F, fresh); day seven, stored for 24 h at 5 °C (E5C); day seven, stored for 24 h at 20 °C (E20C) and day eight control (E8F, fresh 24h time control). The embryos and the storage medium (EquiHold, holding medium, Minitube, Tiefenbach, Germany) from all treatment groups were analyzed for (i) medium temperature, pH, and lipid peroxidation (malondialdehyde; MDA) and (ii) embryo morphology, mRNA expression and DNA methylation (immunohistochemistry and gene-specific DNA methylation). The size of embryos stored at 5 °C was larger (p < 0.01), whereas embryos stored at 20 °C were smaller (p < 0.05) after 24 h. There were no changes in pH and MDA accumulation irrespective of the group. The mRNA expression of specific genes related to growth and development (POU5F1, SOX2, NANOG), maternal recognition of pregnancy (CYP19A1, PTGES2), DNA methylation (DNMT1, DNMT3A, DNMT3B) and apoptosis (BAX) in the E5C and E20C were either up or downregulated (p < 0.05) when compared to controls (E7F and E8F). The immune expression of 5mC and 5hmC was similar among treatment groups. Percentage of methylation in the CpG islands was lower in the specific genes ESR1, NANOG and DNMT1 (p < 0.001) in E20C embryos when compared to E8F (advanced embryo stage). Therefore, our study demonstrates for the first time the gene-specific and global DNA methylation status of fresh equine embryos collected on days seven and eight after ovulation. Although our results suggest some beneficial effects of storage at 20 °C in comparison to 5 °C, the short-term storage, regardless of temperature, modified gene expression and methylation of genes involved in embryo development and may compromise embryo viability and development after transfer.
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do Nascimento AD, Marques JCC, Cezar ARR, Batista AM, Kastelic JP, Câmara DR. Inhibition of Na +, K + -ATPase with ouabain is detrimental to equine blastocysts. Anim Reprod 2020; 17:arAO20190079. [PMID: 32368275 PMCID: PMC7189547 DOI: 10.21451/1984-3143-ar2019-0079] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although equine blastocysts ≤ 300 µm in diameter can be successfully vitrified, larger equine blastocysts are not good candidates for cryopreservation. As Na+, K+-ATPase is involved in maintaining blastocyst expansion, perhaps inhibition of this enzyme would be a viable method of reducing blastocyst diameter prior to cryopreservation. Objectives were to evaluate effects of ouabain-induced inhibition of Na+, K+-ATPase in equine blastocysts. Sixteen mares were ultrasonographically monitored, given deslorelin acetate to induce ovulation, and inseminated. Embryos (D7 and D9) were harvested and Na+, K+-ATPase inhibited for 1 or 6 h by exposure to 10-6 M ouabain, either natural ouabain or conjugated to fluorescein (OuabainFL), during incubation at 37° C. Evaluations included morphometric characteristics (bright field microscopy) and viability (Hoescht 33342 + propidium iodide). Blastocysts incubated for 6 h in Holding medium + ouabain (n=3) had, on average, a 45.7% reduction in diameter, with adverse morphologic features and no re-expansion after subsequent incubation in Holding medium for 12 h. In subsequent studies, even a 1-h exposure to Ouabain or OuabainFL, caused similar reductions, namely 38.7 ± 6.7% (n=5) and 33.6 ± 3.3% (n=7) for D7 and D9 blastocysts, respectively. Ouabain binding was confirmed after OuabainFL exposition and all embryos (n=12) lost viability. We concluded that Na+, K+-ATPase inhibition with ouabain caused death of equine blastocysts and therefore was not a viable method of reducing blastocyst size prior to cryopreservation.
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Affiliation(s)
- Agnelo Douglas do Nascimento
- Departamento de Medicina Veterinária, Laboratório de Reprodução Animal, Universidade Federal de Alagoas, Viçosa, AL, Brasil
| | | | - Allan Rodolf Ribeiro Cezar
- Departamento de Medicina Veterinária, Laboratório de Reprodução Animal, Universidade Federal de Alagoas, Viçosa, AL, Brasil
| | - André Mariano Batista
- Departamento de Medicina Veterinária, Universidade Federal Rural de Pernambuco, Recife, PE, Brasil
| | - John Patrick Kastelic
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | - Diogo Ribeiro Câmara
- Departamento de Medicina Veterinária, Laboratório de Reprodução Animal, Universidade Federal de Alagoas, Viçosa, AL, Brasil
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Gibson C, de Ruijter-Villani M, Rietveld J, Stout TAE. Amino acid transporter expression in the endometrium and conceptus membranes during early equine pregnancy. Reprod Fertil Dev 2019; 30:1675-1688. [PMID: 29903343 DOI: 10.1071/rd17352] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 05/07/2018] [Indexed: 12/29/2022] Open
Abstract
Maternally derived amino acids (AA) are essential for early conceptus development, and specific transporters enhance histotrophic AA content during early ruminant pregnancy. In the present study we investigated AA transporter expression in early equine conceptuses and endometrium, during normal pregnancy and after induction of embryo-uterus asynchrony. 'Normal' conceptuses and endometrium were recovered on Days 7, 14, 21 and 28 after ovulation. To investigate asynchrony, Day 8 embryos were transferred to recipient mares on Day 8 or Day 3, and conceptuses were recovered 6 or 11 days later. Endometrial expression of AA transporters solute carrier family 38 member 2 (SLC38A2), solute carrier family 1 members 4 and 5 (SLC1A4 and SLC1A5) increased during early pregnancy, whereas solute carrier family 7 member 8 (SLC7A8), solute carrier family 43 member 2 (SLC43A2) and solute carrier family 7 member 1 (SLC7A1) SLC7A8, SLC43A2 and SLC7A1 expression decreased and the expression of solute carrier family 1 member 1(SLC1A1) and solute carrier family 7 member 2 (SLC7A2) was unaffected. In conceptus membranes, most transporters studied were upregulated, either after Day 14 (solute carrier family 7 member 5 - SLC7A5, SLC38A2, SLC1A4, SLC1A5 and SLC7A1) or Day 21 (SLC43A2 and SLC7A2). Asynchronous ET indicated that endometrial SLC1A5, SLC1A1 and SLC7A8 are primarily regulated by conceptus factors and/or longer exposure to progesterone. In conclusion, AA transporters are expressed in early equine conceptus membranes and endometrium in specific spatiotemporal patterns. Because conceptuses express a wider range of transporters than the endometrium, we speculate that the equine yolk sac has recruited AA transporters to ensure adequate nutrient provision during an unusually long preimplantation period.
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Affiliation(s)
- Charlotte Gibson
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 114, 3584CM Utrecht, Netherlands
| | - Marta de Ruijter-Villani
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 114, 3584CM Utrecht, Netherlands
| | - Jolanda Rietveld
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 114, 3584CM Utrecht, Netherlands
| | - Tom A E Stout
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 114, 3584CM Utrecht, Netherlands
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Câmara DR, Kastelic JP, Thundathil JC. Role of the Na +/K +-ATPase ion pump in male reproduction and embryo development. Reprod Fertil Dev 2018; 29:1457-1467. [PMID: 27456939 DOI: 10.1071/rd16091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/19/2016] [Indexed: 12/18/2022] Open
Abstract
Na+/K+-ATPase was one of the first ion pumps studied because of its importance in maintaining osmotic and ionic balances between intracellular and extracellular environments, through the exchange of three Na+ ions out and two K+ ions into a cell. This enzyme, which comprises two main subunits (α and β), with or without an auxiliary polypeptide (γ), can have specific biochemical properties depending on the expression of associated isoforms (α1β1 and/or α2β1) in the cell. In addition to the importance of Na+/K+-ATPase in ensuring the function of many tissues (e.g. brain, heart and kidney), in the reproductive tract this protein is essential for embryo development because of its roles in blastocoel formation and embryo hatching. In the context of male reproduction, the discovery of a very specific subunit (α4), apparently restricted to male germ cells, only expressed after puberty and able to influence sperm function (e.g. motility and capacitation), opened a remarkable field for further investigations regarding sperm biology. Therefore, the present review focuses on the importance of Na+/K+-ATPase on male reproduction and embryo development.
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Affiliation(s)
- D R Câmara
- Faculdade de Medicina Veterinária, Universidade Federal de Alagoas, Fazenda São Luiz, s/n, Zona Rural do Município de Viçosa, Viçosa-AL, CEP: 57700-000, Brazil
| | - J P Kastelic
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Dr., NW, Calgary, AB T2N 4N1, Canada
| | - J C Thundathil
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Dr., NW, Calgary, AB T2N 4N1, Canada
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Aurich C, Budik S. Early pregnancy in the horse revisited - does exception prove the rule? J Anim Sci Biotechnol 2015; 6:50. [PMID: 26635959 PMCID: PMC4668677 DOI: 10.1186/s40104-015-0048-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 11/12/2015] [Indexed: 11/10/2022] Open
Abstract
Early equine pregnancy shares many features with that of more intensively assessed domestic animals species, but there are also characteristic differences. Some of those are poorly understood. Descent of the equine conceptus into the uterine lumen occurs at day 5 to 6 after ovulation but is only possible when the embryo secretes prostaglandin E2. Although maintenance of equine pregnancy probably involves secretion of a conceptus derived anti-luteolytic factor, this agent has not been identified. Rapid growth, conceptus mobility and presence of an acellular capsule at the time of maternal recognition of pregnancy, i.e. between days 12 and 14, are prerequisites to avoid pregnancy loss. Progesterone together with 5α-pregnanes is secreted by the corpus luteum and induces the production of endometrial histotroph which is responsible for conceptus nutrition until placention. A stable contact between the outer trophoblast layer of the allantochorion and the luminal epithelium of the endometrium is not established before days 40 to 42 of pregnancy.
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Affiliation(s)
- Christine Aurich
- Artificial Insemination and Embryo Transfer, Vetmeduni Vienna, Veterinärplatz 1, 1210 Vienna, Austria
| | - Sven Budik
- Artificial Insemination and Embryo Transfer, Vetmeduni Vienna, Veterinärplatz 1, 1210 Vienna, Austria
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Aurich C, Budik S. Season Does Not Influence Embryo Recovery Rate and Conceptus Size Until Day 14 After Ovulation in the Horse. Reprod Domest Anim 2015; 50:299-303. [DOI: 10.1111/rda.12490] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 01/07/2015] [Indexed: 11/28/2022]
Affiliation(s)
- C Aurich
- Centre for Artificial Insemination and Embryo Transfer; Vetmeduni Vienna Austria
| | - S Budik
- Centre for Artificial Insemination and Embryo Transfer; Vetmeduni Vienna Austria
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Willmann C, Budik S, Walter I, Aurich C. Influences of treatment of early pregnant mares with the progestin altrenogest on embryonic development and gene expression in the endometrium and conceptus. Theriogenology 2011; 76:61-73. [DOI: 10.1016/j.theriogenology.2011.01.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 01/14/2011] [Accepted: 01/14/2011] [Indexed: 10/18/2022]
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Wilsher S, Allen WR. Uterine influences on embryogenesis and early placentation in the horse revealed by transfer of day 10 embryos to day 3 recipient mares. Reproduction 2009; 137:583-93. [DOI: 10.1530/rep-08-0328] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Eight day 10 horse embryos were transferred non-surgically to recipient mares that had ovulated 7 days after the donors. The embryonic vesicle was seen ultrasonographically in all eight recipients, and three out of eight (38%) of the vesicles developed an embryo proper with a beating heart. Conceptus expansion was initially slower than that in control mares but continued until day 22 (recipient day 15). Time of fixation of the vesicle was related to its diameter, rather than uterine stage. Although the embryo proper first appeared ultrasonographically on day 22, as normal, it grew more slowly and the allantois expanded more slowly than that in control mares with normal pregnancies. The development of endometrial cups and their secretion of equine chorionic gonadotropin in the two mares allowed to remain pregnant to >50 days occurred at a conceptus age ∼7 days later than that in the control mares. The results demonstrated the uniqueness of the horse conceptus in being able to overcome a 7-day asynchrony with the uterus, and also highlighted the overriding influence of the uterine environment on conceptus development in the mare.
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Budik S, Walter I, Tschulenk W, Helmreich M, Deichsel K, Pittner F, Aurich C. Significance of aquaporins and sodium potassium ATPase subunits for expansion of the early equine conceptus. Reproduction 2008; 135:497-508. [DOI: 10.1530/rep-07-0298] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Madan P, Rose K, Watson AJ. Na/K-ATPase beta1 subunit expression is required for blastocyst formation and normal assembly of trophectoderm tight junction-associated proteins. J Biol Chem 2007; 282:12127-34. [PMID: 17317668 DOI: 10.1074/jbc.m700696200] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Na/K-ATPase plays an important role in mediating blastocyst formation. Despite the expression of multiple Na/K-ATPase alpha and beta isoforms during mouse preimplantation development, only the alpha1 and beta1 isoforms have been localized to the basolateral membrane regions of the trophectoderm. The aim of the present study was to selectively down-regulate the Na/K-ATPase beta1 subunit employing microinjection of mouse 1 cell zygotes with small interfering RNA (siRNA) oligos. Experiments comprised of non-injected controls and two groups microinjected with either Stealthtrade mark Na/K-ATPase beta1 subunit oligos or nonspecific Stealthtrade mark siRNA as control. Development to the 2-, 4-, 8-, and 16-cell and morula stages did not vary between the three groups. However, only 2.3% of the embryos microinjected with Na/K-ATPase beta1 subunit siRNA oligos developed to the blastocyst stage as compared with 73% for control-injected and 91% for non-injected controls. Na/K-ATPase beta1 subunit down-regulation was validated by employing reverse transcription-PCR and whole-mount immunofluorescence methods to demonstrate that Na/K-ATPase beta1 subunit mRNAs and protein were not detectable in beta1 subunit siRNA-microinjected embryos. Aggregation chimera experiments between beta1 subunit siRNA-microinjected embryos and controls demonstrated that blockade of blastocyst formation was reversible. The distribution of Na/K-ATPase alpha1 and tight junction-associated proteins occludin and ZO-1 were compared among the three treatment groups. No differences in protein distribution were observed between control groups; however, all three polypeptides displayed an aberrant distribution in Na/K-ATPase beta1 subunit siRNA-microinjected embryos. Our results demonstrate that the beta1 subunit of the Na/K-ATPase is required for blastocyst formation and that this subunit is also required to maintain a normal Na/K-ATPase distribution and localization of tight junction-associated polypeptides during preimplantation development.
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Affiliation(s)
- Pavneesh Madan
- Department of Obstetrics and Gynaecology, University of Western Ontario, Children's Health Research Institute-Victoria Research Laboratories, London, Ontario N6A 4G5, Canada
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Crews LJ, Waelchli RO, Huang CX, Canny MJ, McCully ME, Betteridge KJ. Electrolyte distribution and yolk sac morphology in frozen hydrated equine conceptuses during the second week of pregnancy. Reprod Fertil Dev 2007; 19:804-14. [PMID: 17897583 DOI: 10.1071/rd07050] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2007] [Accepted: 05/21/2007] [Indexed: 11/23/2022] Open
Abstract
To investigate how equine conceptuses expand rapidly despite the hypo-osmolality of their yolk sac fluid, 18 conceptuses, aged 8–12 days and 0.8–10.0 mm in diameter, were examined by cryoscanning electron microscopy and energy dispersive X-ray microanalysis to determine the distribution of Na, Cl and K in their fluids. No osmotic gradient was found between central and peripheral yolk sac fluid. In conceptuses ≥ 6 mm in diameter, the concentrations of both Na and K in the subtrophectodermal compartments were higher than those determined previously in uterine fluid, supporting the concept of osmotic intake of fluid from the uterine environment as far as the compartments. However, electrolyte concentrations in the compartments consistently exceeded those found in the yolk sac, making it likely that ‘uphill’ water transport, rather than a purely osmotic uptake, is involved in yolk sac fluid accumulation. We also speculate that capsule formation could actively contribute to conceptus expansion and thereby to fluid intake.
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Affiliation(s)
- Laura J Crews
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
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Barcroft LC, Moseley AE, Lingrel JB, Watson AJ. Deletion of the Na/K-ATPase alpha1-subunit gene (Atp1a1) does not prevent cavitation of the preimplantation mouse embryo. Mech Dev 2005; 121:417-26. [PMID: 15147760 DOI: 10.1016/j.mod.2004.04.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2003] [Revised: 03/31/2004] [Accepted: 04/06/2004] [Indexed: 11/18/2022]
Abstract
Increases in Na/K-ATPase activity occur concurrently with the onset of cavitation and are associated with increases in Na(+)-pump subunit mRNA and protein expression. We have hypothesized that the alpha1-isozyme of the Na/K-ATPase is required to mediate blastocyst formation. We have tested this hypothesis by characterizing preimplantation development in mice with a targeted disruption of the Na/K-ATPase alpha1-subunit (Atp1a1) using embryos acquired from matings between Atp1a1 heterozygous mice. Mouse embryos homozygous for a null mutation in the Na/K-ATPase alpha1-subunit gene are able to undergo compaction and cavitation. These findings demonstrate that trophectoderm transport mechanisms are maintained in the absence of the predominant isozyme of the Na(+)-pump that has previously been localized to the basolateral membranes of mammalian trophectoderm cells. The presence of multiple isoforms of Na/K-ATPase alpha- and beta-subunits at the time of cavitation suggests that there may be a degree of genetic redundancy amongst isoforms of the catalytic alpha-subunit that allows blastocyst formation to progress in the absence of the alpha1-subunit.
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Affiliation(s)
- L C Barcroft
- Department Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, OH 45267-0524, USA
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Abstract
The developmental changes in the equine conceptus, its maternal environment and their interaction during the first 4 weeks following fertilization are reviewed. Attention is drawn to species-specific events to show why the horse is such a valuable model in which to study early pregnancy.
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Affiliation(s)
- K J Betteridge
- Animal Biotechnology-Embryo Laboratory, Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Ontario, Guelph, Canada
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MacPhee DJ, Jones DH, Barr KJ, Betts DH, Watson AJ, Kidder GM. Differential involvement of Na(+),K(+)-ATPase isozymes in preimplantation development of the mouse. Dev Biol 2000; 222:486-98. [PMID: 10837135 DOI: 10.1006/dbio.2000.9708] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Na(+),K(+)-ATPase plays an essential role in mammalian blastocoel formation (cavitation) by driving trans-epithelial sodium transport. Previously, the alpha1 and beta1 subunit isoforms of this enzyme were identified in preimplantation mouse embryos and were assumed to be responsible for this function. Here we show that mRNAs encoding an additional alpha subunit isoform (alpha3) and the remaining two beta subunit isoforms are also present in preimplantation embryos. Whereas alpha3 mRNA accumulates between the four-cell and the blastocyst stages and thus results from embryonic transcription, the same could not be demonstrated for beta2 and beta3 mRNAs. Immunoblot analyses confirmed that these subunits are present in cavitating embryos. Using confocal immunofluorescence microscopy we found that alpha1 and beta1 subunits are concentrated in the basolateral membranes of the trophectoderm while being equally distributed in plasma membranes of the inner cell mass. In contrast, alpha3, beta2, and beta3 subunits were not detected in plasma membranes. Our current assessment, therefore, is that as many as six isozymes of Na(+),K(+)-ATPase could be involved in preimplantation development although it is primarily the alpha1beta1 isozyme that is responsible for blastocoel formation. Our findings imply that the regulation of sodium transport within the preimplantation mouse embryo is more complex than had been appreciated.
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Affiliation(s)
- D J MacPhee
- Department of Physiology, The University of Western Ontario, London, Ontario, N6A 5C1, Canada
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