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Maucieri AM, Townson DH. Evidence and manipulation of O-GlcNAcylation in granulosa cells of bovine antral follicles†. Biol Reprod 2021; 104:914-923. [PMID: 33550377 PMCID: PMC8023420 DOI: 10.1093/biolre/ioab013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/02/2020] [Accepted: 01/26/2021] [Indexed: 01/15/2023] Open
Abstract
Glucose is a preferred energy substrate for metabolism by bovine granulosa cells (GCs). O-linked N-acetylglucosaminylation (O-GlcNAcylation), is a product of glucose metabolism that occurs as the hexosamine biosynthesis pathway (HBP) shunts O-GlcNAc sugars to serine and threonine residues of proteins. O-GlcNAcylation through the HBP is considered a nutrient sensing mechanism that regulates many cellular processes. Yet little is known of its importance in GCs. Here, O-GlcNAcylation in GCs and its effects on GC proliferation were determined. Bovine ovaries from a slaughterhouse, staged to the mid-to-late estrous period were used. Follicular fluid and GCs were aspirated from small (3-5 mm) and large (>10 mm) antral follicles. Freshly isolated GCs of small follicles exhibited greater expression of O-GlcNAcylation and O-GlcNAc transferase (OGT) than large follicles. Less glucose and more lactate was detectable in the follicular fluid of small versus large follicles. Culture of GCs revealed that inhibition of the HBP via the glutamine fructose-6-phosphate aminotransferase inhibitor, DON (50 μM), impaired O-GlcNAcylation and GC proliferation, regardless of follicle size. Direct inhibition of O-GlcNAcylation via the OGT inhibitor, OSMI-1 (50 μM), also prevented proliferation, but only in GCs of small follicles. Augmentation of O-GlcNAcylation via the O-GlcNAcase inhibitor, Thiamet-G (2.5 μM), had no effect on GC proliferation, regardless of follicle size. The results indicate GCs of bovine antral follicles undergo O-GlcNAcylation, and O-GlcNAcylation is associated with alterations of glucose and lactate in follicular fluid. Disruption of O-GlcNAcylation impairs GC proliferation. Thus, the HBP via O-GlcNAcylation constitutes a plausible nutrient-sensing pathway influencing bovine GC function and follicular growth.
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Affiliation(s)
- Abigail M Maucieri
- Department of Animal and Veterinary Sciences, The University of Vermont, Burlington, VT, USA
| | - David H Townson
- Department of Animal and Veterinary Sciences, The University of Vermont, Burlington, VT, USA
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2
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He M, Zhang T, Yang Y, Wang C. Mechanisms of Oocyte Maturation and Related Epigenetic Regulation. Front Cell Dev Biol 2021; 9:654028. [PMID: 33842483 PMCID: PMC8025927 DOI: 10.3389/fcell.2021.654028] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 02/25/2021] [Indexed: 12/16/2022] Open
Abstract
Meiosis is the basis of sexual reproduction. In female mammals, meiosis of oocytes starts before birth and sustains at the dictyate stage of meiotic prophase I before gonadotropins-induced ovulation happens. Once meiosis gets started, the oocytes undergo the leptotene, zygotene, and pachytene stages, and then arrest at the dictyate stage. During each estrus cycle in mammals, or menstrual cycle in humans, a small portion of oocytes within preovulatory follicles may resume meiosis. It is crucial for females to supply high quality mature oocytes for sustaining fertility, which is generally achieved by fine-tuning oocyte meiotic arrest and resumption progression. Anything that disturbs the process may result in failure of oogenesis and seriously affect both the fertility and the health of females. Therefore, uncovering the regulatory network of oocyte meiosis progression illuminates not only how the foundations of mammalian reproduction are laid, but how mis-regulation of these steps result in infertility. In order to provide an overview of the recently uncovered cellular and molecular mechanism during oocyte maturation, especially epigenetic modification, the progress of the regulatory network of oocyte meiosis progression including meiosis arrest and meiosis resumption induced by gonadotropins is summarized. Then, advances in the epigenetic aspects, such as histone acetylation, phosphorylation, methylation, glycosylation, ubiquitination, and SUMOylation related to the quality of oocyte maturation are reviewed.
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Affiliation(s)
- Meina He
- Department of Biology, School of Basic Medical Science, Guizhou Medical University, Guiyang, China
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
- Key Laboratory of Ministry of Education for Conservation and Utilization of Special Biological Resources in the Western China, College of Life Science, Ningxia University, Yinchuan, China
| | - Tuo Zhang
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
- Key Laboratory of Ministry of Education for Conservation and Utilization of Special Biological Resources in the Western China, College of Life Science, Ningxia University, Yinchuan, China
| | - Yi Yang
- Key Laboratory of Ministry of Education for Conservation and Utilization of Special Biological Resources in the Western China, College of Life Science, Ningxia University, Yinchuan, China
| | - Chao Wang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
- Key Laboratory of Ministry of Education for Conservation and Utilization of Special Biological Resources in the Western China, College of Life Science, Ningxia University, Yinchuan, China
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3
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Sheikh MA, Emerald BS, Ansari SA. Stem cell fate determination through protein O-GlcNAcylation. J Biol Chem 2021; 296:100035. [PMID: 33154167 PMCID: PMC7948975 DOI: 10.1074/jbc.rev120.014915] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 11/05/2020] [Accepted: 11/05/2020] [Indexed: 12/13/2022] Open
Abstract
Embryonic and adult stem cells possess the capability of self-renewal and lineage-specific differentiation. The intricate balance between self-renewal and differentiation is governed by developmental signals and cell-type-specific gene regulatory mechanisms. A perturbed intra/extracellular environment during lineage specification could affect stem cell fate decisions resulting in pathology. Growing evidence demonstrates that metabolic pathways govern epigenetic regulation of gene expression during stem cell fate commitment through the utilization of metabolic intermediates or end products of metabolic pathways as substrates for enzymatic histone/DNA modifications. UDP-GlcNAc is one such metabolite that acts as a substrate for enzymatic mono-glycosylation of various nuclear, cytosolic, and mitochondrial proteins on serine/threonine amino acid residues, a process termed protein O-GlcNAcylation. The levels of GlcNAc inside the cells depend on the nutrient availability, especially glucose. Thus, this metabolic sensor could modulate gene expression through O-GlcNAc modification of histones or other proteins in response to metabolic fluctuations. Herein, we review evidence demonstrating how stem cells couple metabolic inputs to gene regulatory pathways through O-GlcNAc-mediated epigenetic/transcriptional regulatory mechanisms to govern self-renewal and lineage-specific differentiation programs. This review will serve as a primer for researchers seeking to better understand how O-GlcNAc influences stemness and may catalyze the discovery of new stem-cell-based therapeutic approaches.
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Affiliation(s)
- Muhammad Abid Sheikh
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE
| | - Bright Starling Emerald
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE; Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE
| | - Suraiya Anjum Ansari
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE; Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE.
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4
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Jiang X, Pang Y, Zhao S, Hao H, Zhao X, Du W, Wang Y, Zhu H. Thioredoxin-interacting protein regulates glucose metabolism and improves the intracellular redox state in bovine oocytes during in vitro maturation. Am J Physiol Endocrinol Metab 2020; 318:E405-E416. [PMID: 31935112 DOI: 10.1152/ajpendo.00057.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The extent of glucose metabolism during oocyte maturation is closely related to oocyte developmental potential. Thioredoxin-interacting protein (TXNIP) is an α-arrestin family protein that negatively regulates glucose uptake into cells. However, little information is available regarding the function of TXNIP in bovine oocytes. Accordingly, the present study was performed to investigate the influence of TXNIP on glucose metabolism in bovine oocytes during in vitro maturation. Pharmacological inhibition of TXNIP by azaserine enhanced glucose uptake and imparted a specific metabolic effect on glycolysis and pentose phosphate pathway (PPP). RNA interference (RNAi) was adopted to further determine the biological significance of TXNIP in regulating glucose metabolism. The maturation rate and the developmental competence of TXNIP siRNA-treated oocytes were significantly improved. Knockdown of TXNIP in bovine oocytes significantly increased glycolysis by increasing the activities of phosphofructokinase (PFK), pyruvate kinase, and lactate dehydrogenase; pyruvate and lactate production; and intracellular ATP level, as well as mitochondrial activity. Furthermore, glucose metabolism through PPP was also enhanced by TXNIP depletion, as TXNIP siRNA treatment promoted glucose-6-phosphate dehydrogenase (G6PDH) activity and NADPH content, and helped maintain a high level of glutathione and a low level of reactive oxygen species within the oocytes. Further studies revealed that inhibition of TXNIP resulted increases in glucose transporter 1 (GLUT1) expression, as well as PFK1 platelet isoform (PFKP) and G6PDH mRNA levels. These results reveal that TXNIP depletion promotes oocyte maturation by enhancing both glycolysis and the PPP. During in vitro maturation of bovine oocytes, TXNIP serves as a key regulator of glucose uptake by controlling GLUT1 expression.
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Affiliation(s)
- XiaoLong Jiang
- Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
- Key Laboratory of Agricultural Animal and Breeding, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, People's Republic of China
| | - YunWei Pang
- Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - ShanJiang Zhao
- Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - HaiSheng Hao
- Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - XueMing Zhao
- Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - WeiHua Du
- Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - YaChun Wang
- Key Laboratory of Agricultural Animal and Breeding, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, People's Republic of China
| | - HuaBin Zhu
- Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
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Zhou LT, Romar R, Pavone ME, Soriano-Úbeda C, Zhang J, Slawson C, Duncan FE. Disruption of O-GlcNAc homeostasis during mammalian oocyte meiotic maturation impacts fertilization. Mol Reprod Dev 2019; 86:543-557. [PMID: 30793403 DOI: 10.1002/mrd.23131] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 01/04/2019] [Accepted: 01/28/2019] [Indexed: 12/22/2022]
Abstract
Meiotic maturation and fertilization are metabolically demanding processes, and thus the mammalian oocyte is highly susceptible to changes in nutrient availability. O-GlcNAcylation-the addition of a single sugar residue (O-linked β-N-acetylglucosamine) on proteins-is a posttranslational modification that acts as a cellular nutrient sensor and likely modulates the function of oocyte proteins. O-GlcNAcylation is mediated by O-GlcNAc transferase (OGT), which adds O-GlcNAc onto proteins, and O-GlcNAcase (OGA), which removes it. Here we investigated O-GlcNAcylation dynamics in bovine and human oocytes during meiosis and determined the developmental sequelae of its perturbation. OGA, OGT, and multiple O-GlcNAcylated proteins were expressed in bovine cumulus oocyte complexes (COCs), and they were localized throughout the gamete but were also enriched at specific subcellular sites. O-GlcNAcylated proteins were concentrated at the nuclear envelope at prophase I, OGA at the cortex throughout meiosis, and OGT at the meiotic spindles. These expression patterns were evolutionarily conserved in human oocytes. To examine O-GlcNAc function, we disrupted O-GlcNAc cycling during meiotic maturation in bovine COCs using Thiamet-G (TMG), a highly selective OGA inhibitor. Although TMG resulted in a dramatic increase in O-GlcNAcylated substrates in both cumulus cells and the oocyte, there was no effect on cumulus expansion or meiotic progression. However, zygote development was significantly compromised following in vitro fertilization of COCs matured in TMG due to the effects on sperm penetration, sperm head decondensation, and pronuclear formation. Thus, proper O-GlcNAc homeostasis during meiotic maturation is important for fertilization and pronuclear stage development.
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Affiliation(s)
- Luhan T Zhou
- Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Raquel Romar
- Department of Physiology, Faculty of Veterinary Science, University of Murcia, Murcia, Spain
| | - Mary Ellen Pavone
- Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Cristina Soriano-Úbeda
- Department of Physiology, Faculty of Veterinary Science, University of Murcia, Murcia, Spain
| | - John Zhang
- Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Chad Slawson
- Department of Biochemistry and Molecular Biology, University of Kansas Medical School, Kansas City, Kansas
| | - Francesca E Duncan
- Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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Richani D, Gilchrist RB. The epidermal growth factor network: role in oocyte growth, maturation and developmental competence. Hum Reprod Update 2018; 24:1-14. [PMID: 29029246 DOI: 10.1093/humupd/dmx029] [Citation(s) in RCA: 158] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 08/30/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The LH surge induces great physiological changes within the preovulatory follicle, which culminate in the ovulation of a mature oocyte that is capable of supporting embryo and foetal development. However, unlike mural granulosa cells, the oocyte and its surrounding cumulus cells are not directly responsive to LH, indicating that the LH signal is mediated by secondary factors produced by the granulosa cells. The mechanisms by which the oocyte senses the ovulatory LH signal and hence prepares for ovulation has been a subject of considerable controversy for the past four decades. Within the last 15 years several significant insights have been made into the molecular mechanisms orchestrating oocyte development, maturation and ovulation. These findings centre on the epidermal growth factor (EGF) pathway and the role it plays in the complex signalling network that finely regulates oocyte maturation and ovulation. OBJECTIVE AND RATIONALE This review outlines the role of the EGF network during oocyte development and regulation of the ovulatory cascade, and in particular focuses on the effect of the EGF network on oocyte developmental competence. Application of this new knowledge to advances in ART is examined. SEARCH METHODS The PubMed database was used to search for peer-reviewed original and review articles concerning the EGF network. Publications offering a comprehensive description of the role of the EGF network in follicle and oocyte development were used. OUTCOMES It is now clear that acute upregulation of the EGF network is an essential component of the ovulatory cascade as it transmits the LH signal from the periphery of the follicle to the cumulus-oocyte complex (COC). More recent findings have elucidated new roles for the EGF network in the regulation of oocyte development. EGF signalling downregulates the somatic signal 3'5'-cyclic guanine monophosphate that suppresses oocyte meiotic maturation and simultaneously provides meiotic inducing signals. The EGF network also controls translation of maternal transcripts in the quiescent oocyte, a process that is integral to oocyte competence. As a means of restricting the ovulatory signal to the Graffian follicle, most COCs in the ovary are unresponsive to EGF-ligands. Recent studies have revealed that development of a functional EGF signalling network in cumulus cells requires dual endocrine (FSH) and oocyte paracrine cues (growth differentiation factor 9 and bone morphogenetic protein 15), and this occurs progressively in COCs during the last stages of folliculogenesis. Hence, a new concept to emerge is that cumulus cell acquisition of EGF receptor responsiveness represents a developmental hallmark in folliculogenesis, analogous to FSH-induction of LH receptor signalling in mural granulosa cells. Likewise, this event represents a major milestone in the oocyte's developmental progression and acquisition of developmental competence. It is now clear that EGF signalling is perturbed in COCs matured in vitro. This has inspired novel concepts in IVM systems to ameliorate this perturbation, resulting in improved oocyte developmental competence. WIDER IMPLICATIONS An oocyte of high quality is imperative for fertility. Elucidating the fundamental molecular and cellular mechanims by which the EGF network regulates oocyte maturation and ovulation can be expected to open new opportunities in ART. This knowledge has already led to advances in oocyte IVM in animal models. Translation of such advances into a clinical setting should increase the efficacy of IVM, making it a viable treatment option for a wide range of patients, thereby simplifying fertility treatment and bringing substantial cost and health benefits.
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Affiliation(s)
- Dulama Richani
- School of Women's and Children's Health, Discipline of Obstetrics and Gynaecology, University of New South Wales Sydney, NSW 2052, Australia
| | - Robert B Gilchrist
- School of Women's and Children's Health, Discipline of Obstetrics and Gynaecology, University of New South Wales Sydney, NSW 2052, Australia
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Brown HM, Green ES, Tan TCY, Gonzalez MB, Rumbold AR, Hull ML, Norman RJ, Packer NH, Robertson SA, Thompson JG. Periconception onset diabetes is associated with embryopathy and fetal growth retardation, reproductive tract hyperglycosylation and impaired immune adaptation to pregnancy. Sci Rep 2018; 8:2114. [PMID: 29391475 PMCID: PMC5794861 DOI: 10.1038/s41598-018-19263-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 12/22/2017] [Indexed: 01/04/2023] Open
Abstract
Diabetes has been linked with impaired fertility but the underlying mechanisms are not well defined. Here we use a streptozotocin-induced diabetes mouse model to investigate the cellular and biochemical changes in conceptus and maternal tissues that accompany hyperglycaemia. We report that streptozotocin treatment before conception induces profound intra-cellular protein β-O-glycosylation (O-GlcNAc) in the oviduct and uterine epithelium, prominent in early pregnancy. Diabetic mice have impaired blastocyst development and reduced embryo implantation rates, and delayed mid-gestation growth and development. Peri-conception changes are accompanied by increased expression of pro-inflammatory cytokine Trail, and a trend towards increased Il1a, Tnf and Ifng in the uterus, and changes in local T-cell dynamics that skew the adaptive immune response to pregnancy, resulting in 60% fewer anti-inflammatory regulatory T-cells within the uterus-draining lymph nodes. Activation of the heat shock chaperones, a mechanism for stress deflection, was evident in the reproductive tract. Additionally, we show that the embryo exhibits elevated hyper-O-GlcNAcylation of both cytoplasmic and nuclear proteins, associated with activation of DNA damage (ɣH2AX) pathways. These results advance understanding of the impact of peri-conception diabetes, and provide a foundation for designing interventions to support healthy conception without propagation of disease legacy to offspring.
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Affiliation(s)
- Hannah M Brown
- Robinson Research Institute, Adelaide Medical School, University of Adelaide, Adelaide, Australia. .,Australian Research Council (ARC) Centre for Nanoscale Biophotonics, University of Adelaide, Adelaide, Australia.
| | - Ella S Green
- Robinson Research Institute, Adelaide Medical School, University of Adelaide, Adelaide, Australia
| | - Tiffany C Y Tan
- Robinson Research Institute, Adelaide Medical School, University of Adelaide, Adelaide, Australia
| | - Macarena B Gonzalez
- Robinson Research Institute, Adelaide Medical School, University of Adelaide, Adelaide, Australia
| | - Alice R Rumbold
- Robinson Research Institute, Adelaide Medical School, University of Adelaide, Adelaide, Australia
| | - M Louise Hull
- Robinson Research Institute, Adelaide Medical School, University of Adelaide, Adelaide, Australia.,Fertility SA, Adelaide, Australia
| | - Robert J Norman
- Robinson Research Institute, Adelaide Medical School, University of Adelaide, Adelaide, Australia.,Fertility SA, Adelaide, Australia
| | - Nicolle H Packer
- ARC Centre for Nanoscale Biophotonics, Department of Molecular Sciences, Macquarie University, Sydney, Australia
| | - Sarah A Robertson
- Robinson Research Institute, Adelaide Medical School, University of Adelaide, Adelaide, Australia
| | - Jeremy G Thompson
- Robinson Research Institute, Adelaide Medical School, University of Adelaide, Adelaide, Australia.,Australian Research Council (ARC) Centre for Nanoscale Biophotonics, University of Adelaide, Adelaide, Australia
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8
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Wong SL, Wu LL, Robker RL, Thompson JG, McDowall MLS. Hyperglycaemia and lipid differentially impair mouse oocyte developmental competence. Reprod Fertil Dev 2017; 27:583-92. [PMID: 25714624 DOI: 10.1071/rd14328] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 01/06/2015] [Indexed: 01/09/2023] Open
Abstract
Maternal diabetes and obesity are characterised by elevated blood glucose, insulin and lipids, resulting in upregulation of specific fuel-sensing and stress signalling pathways. Previously, we demonstrated that, separately, upregulation of the hexosamine biosynthetic pathway (HBP; under hyperglycaemic conditions) and endoplasmic reticulum (ER) stress (due to hyperlipidaemia) pathways reduce blastocyst development and alter oocyte metabolism. In order to begin to understand how both glucose and lipid metabolic disruptions influence oocyte developmental competence, in the present study we exposed mouse cumulus-oocyte complexes to hyperglycaemia (30mM) and/or lipid (40μM) and examined the effects on embryo development. The presence of glucosamine (GlcN; a hyperglycaemic mimetic) or increased lipid during in vitro maturation severely perturbed blastocyst development (P<0.05). Hyperglycaemia, GlcN and hyperglycaemia + lipid treatments significantly increased HBP activity, increasing total O-linked glycosylation (O-GlcNAcylation) of proteins (P<0.0001). All treatments also induced ER stress pathways, indicated by the expression of specific ER stress genes. The expression of genes encoding the HBP enzymes glutamine:fructose-6-phosphate amidotransferase 2 (Gfpt2) and O-linked β-N-acetylglucosaminyltransferase (Ogt) was repressed following lipid treatment (P<0.001). These findings partially implicate the mechanism of O-GlcNAcylation and ER stress as likely contributors to compromised fertility of obese women.
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Affiliation(s)
- Siew L Wong
- Robinson Research Institute, School of Paediatrics and Reproductive Health, The University of Adelaide, Medical School, Frome Road, Adelaide, SA 5005, Australia
| | - Linda L Wu
- Robinson Research Institute, School of Paediatrics and Reproductive Health, The University of Adelaide, Medical School, Frome Road, Adelaide, SA 5005, Australia
| | - Rebecca L Robker
- Robinson Research Institute, School of Paediatrics and Reproductive Health, The University of Adelaide, Medical School, Frome Road, Adelaide, SA 5005, Australia
| | - Jeremy G Thompson
- Robinson Research Institute, School of Paediatrics and Reproductive Health, The University of Adelaide, Medical School, Frome Road, Adelaide, SA 5005, Australia
| | - Melanie L Sutton McDowall
- Robinson Research Institute, School of Paediatrics and Reproductive Health, The University of Adelaide, Medical School, Frome Road, Adelaide, SA 5005, Australia
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9
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Jung JH, Iwabuchi K, Yang Z, Loeken MR. Embryonic Stem Cell Proliferation Stimulated By Altered Anabolic Metabolism From Glucose Transporter 2-Transported Glucosamine. Sci Rep 2016; 6:28452. [PMID: 27311888 PMCID: PMC4911601 DOI: 10.1038/srep28452] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 06/02/2016] [Indexed: 01/19/2023] Open
Abstract
The hexose transporter, GLUT2 (SLC2A2), which is expressed by mouse embryos, is important for survival before embryonic day 10.5, but its function in embryos is unknown. GLUT2 can transport the amino sugar glucosamine (GlcN), which could increase substrate for the hexosamine biosynthetic pathway (HBSP) that produces UDP-N-acetylglucosamine for O-linked N-acetylglucosamine modification (O-GlcNAcylation) of proteins. To understand this, we employed a novel murine embryonic stem cell (ESC) line that, like mouse embryos, expresses functional GLUT2 transporters. GlcN stimulated ESC proliferation in a GLUT2-dependent fashion but did not regulate pluripotency. Stimulation of proliferation was not due to increased O-GlcNAcylation. Instead, GlcN decreased dependence of the HBSP on fructose-6-PO4 and glutamine. Consequently, glycolytic- and glutamine-derived intermediates that are needed for anabolic metabolism were increased. Thus, maternally obtained GlcN may increase substrates for biomass accumulation by embryos, as exogenous GlcN does for GLUT2-expressing ESC, and may explain the need for GLUT2 expression by embryos.
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Affiliation(s)
- Jin Hyuk Jung
- Section on Islet Cell and Regenerative Biology Joslin Diabetes Center, Boston, MA 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Kumiko Iwabuchi
- Section on Islet Cell and Regenerative Biology Joslin Diabetes Center, Boston, MA 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Zhihong Yang
- Section on Islet Cell and Regenerative Biology Joslin Diabetes Center, Boston, MA 02215, USA.,Section on Vascular Cell Biology Harvard Medical School, Boston, MA 02115, USA
| | - Mary R Loeken
- Section on Islet Cell and Regenerative Biology Joslin Diabetes Center, Boston, MA 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
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10
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Pantaleon M. The Role of Hexosamine Biosynthesis and Signaling in Early Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 843:53-76. [DOI: 10.1007/978-1-4939-2480-6_3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Frank L, Sutton-McDowall M, Brown H, Russell D, Gilchrist R, Thompson J. Hyperglycaemic conditions perturb mouse oocyte in vitro developmental competence via beta-O-linked glycosylation of Heat shock protein 90. Hum Reprod 2014; 29:1292-303. [DOI: 10.1093/humrep/deu066] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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12
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Richani D, Sutton-McDowall ML, Frank LA, Gilchrist RB, Thompson JG. Effect of epidermal growth factor-like peptides on the metabolism of in vitro- matured mouse oocytes and cumulus cells. Biol Reprod 2014; 90:49. [PMID: 24451986 DOI: 10.1095/biolreprod.113.115311] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Oocyte in vitro maturation (IVM) is an assisted reproductive technology that involves the maturation of cumulus-oocyte complexes (COCs) that are then capable of normal development. We have shown that epidermal growth factor (EGF)-like peptide signaling is perturbed in mouse COCs undergoing IVM when matured with follicle-stimulating hormone (FSH) and/or EGF, but supplementation of IVM with EGF-like peptides amphiregulin or epiregulin improves oocyte developmental competence. Here we aimed to determine whether EGF-like peptides regulate COC metabolism. Immature 129/Sv mouse COCs underwent IVM with FSH, EGF, amphiregulin, epiregulin, betacellulin, or no treatment (control). Epiregulin significantly increased intraoocyte flavin adenine dinucleotide (FAD) and REDOX (reduction and oxidation) ratio compared to FSH and control. Amphiregulin and epiregulin significantly increased the proportion of J aggregates (from JC-1) in oocyte mitochondria compared to control, FSH, or EGF, and this coupled with FAD and REDOX measures indicates greater mitochondrial activity. There were no differences in glucose consumption, lactate production, or glycolysis between COCs matured with FSH, EGF, and EGF-like peptides. COCs matured with EGF or EGF-like peptides exhibited significantly higher mRNA expression of the hexosamine biosynthesis pathway (HBP) rate-limiting enzyme gene Gfpt2, Has2 expression, and global beta-O-linked glycosylation of proteins, compared to control or FSH, suggesting greater HBP activity. Our findings suggest that 1) EGF-like peptides, particularly epiregulin, induce more oocyte mitochondrial activity than EGF or FSH and 2) EGF-like peptides and EGF induce greater HBP activity, enabling more hyaluronic acid synthesis and protein beta-O-linked glycosylation. These metabolic alterations may be a mechanism by which EGF-like peptides increase oocyte developmental competence.
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Affiliation(s)
- Dulama Richani
- Research Centre for Reproductive Health, Discipline of Obstetrics and Gynaecology, The Robinson Institute, School of Paediatrics and Reproductive Health, The University of Adelaide, Adelaide, South Australia, Australia
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Sugimura S, Ritter LJ, Sutton-McDowall ML, Mottershead DG, Thompson JG, Gilchrist RB. Amphiregulin co-operates with bone morphogenetic protein 15 to increase bovine oocyte developmental competence: effects on gap junction-mediated metabolite supply. ACTA ACUST UNITED AC 2014; 20:499-513. [DOI: 10.1093/molehr/gau013] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Frank LA, Sutton-McDowall ML, Gilchrist RB, Thompson JG. The effect of peri-conception hyperglycaemia and the involvement of the hexosamine biosynthesis pathway in mediating oocyte and embryo developmental competence. Mol Reprod Dev 2014; 81:391-408. [DOI: 10.1002/mrd.22299] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 12/31/2013] [Indexed: 12/12/2022]
Affiliation(s)
- Laura A. Frank
- The Robinson Institute, The Research Centre for Reproductive Health, School of Paediatrics and Reproductive Health, The University of Adelaide; Adelaide South Australia Australia
| | - Melanie L. Sutton-McDowall
- The Robinson Institute, The Research Centre for Reproductive Health, School of Paediatrics and Reproductive Health, The University of Adelaide; Adelaide South Australia Australia
| | - Robert B. Gilchrist
- The Robinson Institute, The Research Centre for Reproductive Health, School of Paediatrics and Reproductive Health, The University of Adelaide; Adelaide South Australia Australia
| | - Jeremy G. Thompson
- The Robinson Institute, The Research Centre for Reproductive Health, School of Paediatrics and Reproductive Health, The University of Adelaide; Adelaide South Australia Australia
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Hatzirodos N, Irving-Rodgers HF, Hummitzsch K, Harland ML, Morris SE, Rodgers RJ. Transcriptome profiling of granulosa cells of bovine ovarian follicles during growth from small to large antral sizes. BMC Genomics 2014; 15:24. [PMID: 24422759 PMCID: PMC3898003 DOI: 10.1186/1471-2164-15-24] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Accepted: 01/02/2014] [Indexed: 12/02/2022] Open
Abstract
Background At later stages of folliculogenesis, the mammalian ovarian follicle contains layers of epithelial granulosa cells surrounding an antral cavity. During follicle development granulosa cells replicate, secrete hormones and support the growth of the oocyte. In cattle, the follicle needs to grow > 10 mm in diameter to allow an oocyte to ovulate, following which the granulosa cells cease dividing and differentiate into the specialised cells of the corpus luteum. To better understand the molecular basis of follicular growth and granulosa cell maturation, we undertook transcriptome profiling of granulosa cells from small (< 5 mm; n = 10) and large (> 10 mm, n = 4) healthy bovine follicles using Affymetrix microarrays (24,128 probe sets). Results Principal component analysis for the first two components and hierarchical clustering showed clustering into two groups, small and large, with the former being more heterogeneous. Size-frequency distributions of the coefficient of variation of the signal intensities of each probe set also revealed that small follicles were more heterogeneous than the large. IPA and GO enrichment analyses revealed that processes of axonal guidance, immune signalling and cell rearrangement were most affected in large follicles. The most important networks were associated with: (A) Notch, SLIT/ROBO and PI3K signalling, and (B) ITGB5 and extracellular matrix signalling through extracellular signal related kinases (ERKs). Upstream regulator genes which were predicted to be active in large follicles included STAT and XBP1. By comparison, developmental processes such as those stimulated by KIT, IHH and MEST were most active in small follicles. MGEA5 was identified as an upstream regulator in small follicles. It encodes an enzyme that modifies the activity of many target proteins, including those involved in energy sensing, by removal of N-acetylglucosamine from serine and threonine residues. Conclusions Our data suggest that as follicles enlarge more genes and/or pathways are activated than are inactivated, and gene expression becomes more uniform. These findings could be interpreted that either the cells in large follicles are more uniform in their gene expression, or that follicles are more uniform or a combination of both and that additional factors, such as LH, are additionally controlling the granulosa cells.
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Affiliation(s)
| | | | | | | | | | - Raymond J Rodgers
- Research Centre for Reproductive Health, Discipline of Obstetrics and Gynaecology, School of Paediatrics and Reproductive Health, Robinson Institute, University of Adelaide, Adelaide, SA 5005, Australia.
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Gook DA, Edgar DH, Lewis K, Sheedy JR, Gardner DK. Impact of oxygen concentration on adult murine pre-antral follicle development in vitro and the corresponding metabolic profile. Mol Hum Reprod 2013; 20:31-41. [PMID: 24013158 DOI: 10.1093/molehr/gat062] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Oxygen concentration during in vitro culture has a significant effect on the physiology of embryos, altering metabolic profile and developmental outcome. Although atmospheric oxygen has been used routinely for the culture of ovarian follicles, oxygen concentration may also be critical for follicle growth but the optimal concentration has not been determined. In this study, mechanically isolated primary and secondary follicles (80-140 µm diameter) from adult mouse ovaries were cultured in serum-free conditions for 8 days in either 5 or 20% oxygen to determine growth (follicular diameter), morphology and viability. For each oxygen concentration, half of the medium was replaced on Days 2, 4 and 6 or on Day 4 only. In the latter group, metabolic analysis of spent follicular culture media was performed by (1)H-NMR. The proportion of viable, growing follicles was significantly (P < 0.0001) higher in 5% than in 20% oxygen (59% versus 8%). Reducing the frequency of medium replacement during culture in 5% oxygen resulted in significantly (P < 0.001) more viable follicles (79 versus 46%). In 20% oxygen, poor follicular viability was observed irrespective of the frequency of medium replacement (8 and 10% respectively). Metabolic profiles showed marked differences in amino acid and carbohydrate utilization with respect to both oxygen concentration and between Days 4 and 8 of development. Metabolites which significantly discriminated between oxygen concentration at both time points were glucose consumption, lactate utilization, alanine, alanyl-glutamine, leucine and proline. In conclusion, the poor in vitro follicular development previously observed in minimal culture conditions may reflect the use of 20% oxygen. Frequent medium replenishment is not necessary and does not overcome the detrimental effect of high oxygen on follicle viability. Further optimization of culture conditions would benefit from metabolic analyses and the use of 5% oxygen should be tested further for impact on functional aspects of follicle culture such as steroid production which is currently unknown.
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Affiliation(s)
- Debra A Gook
- Reproductive Services, Royal Women's Hospital, Grattan Street, Parkville, VIC 3052, Australia
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17
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Tsai JH, Schulte M, O'Neill K, Chi MMY, Frolova AI, Moley KH. Glucosamine inhibits decidualization of human endometrial stromal cells and decreases litter sizes in mice. Biol Reprod 2013; 89:16. [PMID: 23718985 DOI: 10.1095/biolreprod.113.108571] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Embryo implantation in the uterus depends on decidualization of the endometrial stromal cells (ESCs), and glucose utilization via the pentose phosphate pathway is critical in this process. We hypothesized that the amino sugar glucosamine may block the pentose phosphate pathway via inhibition of the rate-limiting enzyme glucose-6-phosphate dehydrogenase in ESCs and therefore impair decidualization and embryo implantation, thus preventing pregnancy. Both human primary and immortalized ESCs were decidualized in vitro in the presence of 0, 2.5, or 5 mM glucosamine for 9 days. Viability assays demonstrated that glucosamine was well tolerated by human ESCs. Exposure of human ESCs to glucosamine resulted in significant decreases in the activity and expression of glucose-6-phosphate dehydrogenase and in the mRNA expression of the decidual markers prolactin, somatostatin, interleukin-15, and left-right determination factor 2. In mouse ESCs, expression of the decidual marker Prp decreased upon addition of glucosamine. In comparison with control mice, glucosamine-treated mice showed weak artificial deciduoma formation along the stimulated uterine horn. In a complementary in vivo experiment, a 60-day-release glucosamine (15, 150, or 1500 μg) or placebo pellet was implanted in a single uterine horn of mice. Mice with a glucosamine pellet delivered fewer live pups per litter than those with a control pellet, and pup number returned to normal after the end of the pellet-active period. In conclusion, glucosamine is a nonhormonal inhibitor of decidualization of both human and mouse ESCs and of pregnancy in mice. Our data indicate the potential for development of glucosamine as a novel, reversible, nonhormonal contraceptive.
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Affiliation(s)
- Jui-He Tsai
- Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, MO, USA
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18
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Schelbach CJ, Robker RL, Bennett BD, Gauld AD, Thompson JG, Kind KL. Altered pregnancy outcomes in mice following treatment with the hyperglycaemia mimetic, glucosamine, during the periconception period. Reprod Fertil Dev 2013; 25:405-16. [DOI: 10.1071/rd11313] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 03/31/2012] [Indexed: 01/29/2023] Open
Abstract
Exposure of cumulus–oocyte complexes to the hyperglycaemia mimetic, glucosamine, during in vitro maturation impairs embryo development, potentially through upregulation of the hexosamine biosynthesis pathway. This study examined the effects of in vivo periconception glucosamine exposure on reproductive outcomes in young healthy mice, and further assessed the effects in overweight mice fed a high-fat diet. Eight-week-old mice received daily glucosamine injections (20 or 400 mg kg–1) for 3–6 days before and 1 day after mating (periconception). Outcomes were assessed at Day 18 of gestation. Glucosamine treatment reduced litter size independent of dose. A high-fat diet (21% fat) for 11 weeks before and during pregnancy reduced fetal size. No additional effects of periconception glucosamine (20 mg kg–1) on pregnancy outcomes were observed in fat-fed mice. In 16-week-old mice fed the control diet, glucosamine treatment reduced fetal weight and increased congenital abnormalities, but did not alter litter size. As differing effects of glucosamine were observed in 8-week-old and 16-week-old mice, maternal age effects were assessed. Periconception glucosamine at 8 weeks reduced litter size, whereas glucosamine at 16 weeks reduced fetal size. Thus, in vivo periconception glucosamine exposure perturbs reproductive outcomes in mice, with the nature of the outcomes dependent upon maternal age.
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Frank LA, Sutton-McDowall ML, Russell DL, Wang X, Feil DK, Gilchrist RB, Thompson JG. Effect of varying glucose and glucosamine concentration in vitro on mouse oocyte maturation and developmental competence. Reprod Fertil Dev 2013; 25:1095-104. [DOI: 10.1071/rd12275] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 10/07/2012] [Indexed: 11/23/2022] Open
Abstract
The effects of hyper- and hypo-glycaemic conditions during the in vitro maturation of mouse cumulus–oocyte complexes on developmental competence were examined, with an emphasis on the role of the hexosamine biosynthesis pathway. A low (1 mM) glucose concentration achieved optimal oocyte competence (3-fold higher blastocyst development rate compared with high (30 mM) glucose, P < 0.05). In addition, glucose supplementation during only the first hour after release from the follicle was necessary and sufficient to support oocyte maturation and embryo development to the blastocyst stage. Glucosamine (a known hyperglycaemic mimetic and specific activator of the hexosamine pathway) was able to substitute for glucose during this first hour, indicating that flux through the hexosamine pathway is essential for oocyte competence. In the absence of glucose throughout the maturation period, glucosamine was not able to increase developmental competence, and at higher concentrations (2.5 and 5 mM) had a detrimental effect on MII and blastocyst development rates, compared with controls (P < 0.05). These experiments underscore the importance of glucose metabolic pathways during in vitro maturation and support the concept that excess flux through the hexosamine pathway has detrimental consequences.
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Lim CH, Jeong W, Lim W, Kim J, Song G, Bazer FW. Differential Expression of Select Members of the SLC Family of Genes and Regulation of Expression by MicroRNAs in the Chicken Oviduct1. Biol Reprod 2012; 87:145. [DOI: 10.1095/biolreprod.112.101444] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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Dunning KR, Watson LN, Sharkey DJ, Brown HM, Norman RJ, Thompson JG, Robker RL, Russell DL. Molecular Filtration Properties of the Mouse Expanded Cumulus Matrix: Controlled Supply of Metabolites and Extracellular Signals to Cumulus Cells and the Oocyte1. Biol Reprod 2012; 87:89. [DOI: 10.1095/biolreprod.111.096271] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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22
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Jang H, Kim TW, Yoon S, Choi SY, Kang TW, Kim SY, Kwon YW, Cho EJ, Youn HD. O-GlcNAc regulates pluripotency and reprogramming by directly acting on core components of the pluripotency network. Cell Stem Cell 2012; 11:62-74. [PMID: 22608532 DOI: 10.1016/j.stem.2012.03.001] [Citation(s) in RCA: 237] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 01/20/2012] [Accepted: 03/01/2012] [Indexed: 01/03/2023]
Abstract
O-linked-N-acetylglucosamine (O-GlcNAc) has emerged as a critical regulator of diverse cellular processes, but its role in embryonic stem cells (ESCs) and pluripotency has not been investigated. Here we show that O-GlcNAcylation directly regulates core components of the pluripotency network. Blocking O-GlcNAcylation disrupts ESC self-renewal and reprogramming of somatic cells to induced pluripotent stem cells. The core reprogramming factors Oct4 and Sox2 are O-GlcNAcylated in ESCs, but the O-GlcNAc modification is rapidly removed upon differentiation. O-GlcNAc modification of threonine 228 in Oct4 regulates Oct4 transcriptional activity and is important for inducing many pluripotency-related genes, including Klf2, Klf5, Nr5a2, Tbx3, and Tcl1. A T228A point mutation that eliminates this O-GlcNAc modification reduces the capacity of Oct4 to maintain ESC self-renewal and reprogram somatic cells. Overall, our study makes a direct connection between O-GlcNAcylation of key regulatory transcription factors and the activity of the pluripotency network.
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Affiliation(s)
- Hyonchol Jang
- National Research Laboratory for Metabolic Checkpoint, Departments of Biomedical Sciences and Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
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23
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Wang Q, Chi MM, Moley KH. Live imaging reveals the link between decreased glucose uptake in ovarian cumulus cells and impaired oocyte quality in female diabetic mice. Endocrinology 2012; 153:1984-9. [PMID: 22294751 PMCID: PMC3320263 DOI: 10.1210/en.2011-1815] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Maternal diabetes has been demonstrated to adversely affect preimplantation embryo development and pregnancy outcomes. Emerging data suggest that these effects are associated with compromised oocyte quality. However, direct evidence of a pathway by which maternal diabetes exerts its effects on the oocyte is still lacking. Cumulus cells are metabolically coupled to oocytes, and bidirectional communication between them is essential for the development and functions of both compartments. The primary focus of this work was to evaluate the connection between glucose uptake in cumulus cells and oocyte quality in diabetic mice. This experiment has been difficult, because cumulus cells need to be separated from oocytes and labeled with isotope in the process of measuring glucose uptake. Here, we report a method for live imaging glucose transport in single cumulus-oocyte complexes using a fluorescent glucose analog (6-(N-(7-nitrobenz-2-oxa-1,3-diazol- 4-yl)amino)-6-deoxyglucose). By tracking the ATP content and spindle/chromosome status in individual oocytes surrounded by cumulus cells with differing glucose uptake activity, we reveal that compromised oocyte quality in diabetic mice is linked to decreased glucose uptake in cumulus cells.
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Affiliation(s)
- Qiang Wang
- Department of Obstetrics and Gynecology, Washington University School of Medicine, 425 South Euclid Avenue, Campus Box 8064, St. Louis, Missouri 63110, USA
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24
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Silva E, Paczkowski M, Krisher RL. The effect of leptin on maturing porcine oocytes is dependent on glucose concentration. Mol Reprod Dev 2012; 79:296-307. [PMID: 22368147 DOI: 10.1002/mrd.22029] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 01/27/2012] [Indexed: 12/23/2022]
Abstract
Increased body weight is often accompanied by increased circulating levels of leptin and glucose, which alters glucose metabolism in various tissues, including perhaps the oocyte. Alteration of glucose metabolism impacts oocyte function and may contribute to the subfertility often associated with obese individuals. The objective of this study was to determine the effect of leptin (0, 10, and 100 ng/ml) on the oocyte and cumulus cells during in vitro maturation under differing glucose concentrations. We examined the effects of leptin on oocyte maturation, blastocyst development, and/or gene expression in oocytes and cumulus cells (IRS1, IGF1, PPARγ, IL6, GLUT1) in a physiological glucose (2 mM) and high glucose (50 mM) environment. We also evaluated the effect of leptin on glucose metabolism via glycolysis and the pentose phosphate pathway. In a physiological glucose environment, leptin did not have an influence on oocyte maturation, blastocyst development, or oocyte gene expression. Expression of GLUT1 in cumulus cells was downregulated with 100 ng/ml leptin treatment, but did not affect oocyte glucose metabolism. In a high glucose environment, oocyte maturation and glycolysis were decreased, but in the presence of 100 ng/ml leptin, these parameters were improved to levels similar to control. This effect is potentially mediated by an upregulation of oocyte IRS1 and a correction of cumulus cell IGF1 expression. The present study demonstrates that in a physiological glucose concentration, leptin plays a negligible role in oocyte function. However, leptin appears to modulate the deleterious impact of a high glucose environment on oocyte function.
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Affiliation(s)
- Elena Silva
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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25
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Clark AR, Stokes YM, Thompson JG. Estimation of glucose uptake by ovarian follicular cells. Ann Biomed Eng 2011; 39:2654-67. [PMID: 21769539 DOI: 10.1007/s10439-011-0353-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 07/06/2011] [Indexed: 10/18/2022]
Abstract
In vitro maturation (IVM) of mammalian oocytes provides an alternative to traditional in vitro fertilization techniques for clinical treatment of infertility or animal breeding. IVM involves the collection of oocytes from the ovary prior to ovulation, with maturation occurring in a laboratory environment. The success of IVM is highly sensitive to the in vitro nutrient environment. The nurse cells surrounding the oocyte, known as cumulus cells, regulate this environment and removal of these cells reduces the ability of the oocyte to develop following insemination. Determining the nature of the interaction between the oocyte and cumulus cells, collectively called the cumulus-oocyte complex (COC), is a difficult task experimentally. Here we use a combination of experimental and mathematical techniques to investigate glucose transport within bovine COCs and find quantitative estimates of the glucose uptake rates of the oocyte and cumulus cells. Surprisingly, our modeling shows the rate of uptake of glucose by the oocyte to increase and then decrease with concentration, a result that needs further experimental investigation but which supports the expectation that high and low glucose concentrations are detrimental to oocyte development. The methodology described is suitable for use across species and for investigating the transport of other important nutrients within the COC.
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Affiliation(s)
- A R Clark
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.
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26
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Sutton-McDowall ML, Gilchrist RB, Thompson JG. The pivotal role of glucose metabolism in determining oocyte developmental competence. Reproduction 2010; 139:685-95. [PMID: 20089664 DOI: 10.1530/rep-09-0345] [Citation(s) in RCA: 332] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The environment that the cumulus oocyte complex (COC) is exposed to during either in vivo or in vitro maturation (IVM) can have profound effects on the success of fertilisation and subsequent embryo development. Glucose is a pivotal metabolite for the COC and is metabolised by glycolysis, the pentose phosphate pathway (PPP), the hexosamine biosynthesis pathway (HBP) and the polyol pathway. Over the course of oocyte maturation, a large proportion of total glucose is metabolised via the glycolytic pathway to provide substrates such as pyruvate for energy production. Glucose is also the substrate for many cellular functions during oocyte maturation, including regulation of nuclear maturation and redox state via the PPP and for the synthesis of substrates of extracellular matrices (cumulus expansion) and O-linked glycosylation (cell signalling) via the HBP. However, the oocyte is susceptible to glucose concentration-dependent perturbations in nuclear and cytoplasmic maturation, leading to poor embryonic development post-fertilisation. For example, glucose concentrations either too high or too low result in precocious resumption of nuclear maturation. This review will discuss the relevant pathways of glucose metabolism by COCs during in vivo maturation and IVM, including the relative contribution of the somatic and gamete compartments of the COC to glucose metabolism. The consequences of exposing COCs to abnormal glucose concentrations will also be examined, either during IVM or by altered maternal environments, such as during hyperglycaemia induced by diabetes and obesity.
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Affiliation(s)
- Melanie L Sutton-McDowall
- School of Paediatrics and Reproductive Health, The Robinson Institute, Research Centre for Reproductive Health, The University of Adelaide, Adelaide, South Australia 5005, Australia.
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27
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Schelbach CJ, Kind KL, Lane M, Thompson JG. Mechanisms contributing to the reduced developmental competence of glucosamine-exposed mouse oocytes. Reprod Fertil Dev 2010; 22:771-9. [DOI: 10.1071/rd09193] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Accepted: 11/04/2009] [Indexed: 01/20/2023] Open
Abstract
Glucosamine (GlcN) is a widely used hyperglycaemia mimetic because of its ability to upregulate the ‘energy-sensing’ hexosamine biosynthesis pathway in a dose-dependent manner. A previous study demonstrated that addition of GlcN (2.5–5 mM) during IVM of cattle and pig cumulus–oocyte complexes (COC) inhibited development following fertilisation and early cleavage. In the present study, we demonstrate that the addition of 2.5 mM GlcN during IVM of mouse COCs similarly inhibits embryo development, with the degree of inhibition dependent upon the availability of glucose in the maturation medium. Furthermore, we determined that the effect of GlcN is likely mediated by the cumulus cell vestment, because we failed to observe inhibitory effects of GlcN following maturation of denuded (and therefore already developmentally compromised) oocytes. As with cattle oocytes, inhibition of O-linked glycosylation of unknown proteins within mouse cumulus cells significantly reversed the effects of GlcN. Finally, we also provide preliminary evidence that GlcN may inhibit the pentose phosphate metabolic pathway within the oocyte, an effect possibly mediated by cumulus cells in intact COCs. Collectively, our results demonstrate that GlcN inhibits the developmental competence of IVM mouse oocytes and suggest that this occurs via cumulus cell-mediated mechanisms. Therefore, the in vitro addition of GlcN is a useful experimental tool to determine the mechanisms of hyperglycaemic responses within COCs.
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28
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Pantaleon M, Tan HY, Kafer GR, Kaye PL. Toxic effects of hyperglycemia are mediated by the hexosamine signaling pathway and o-linked glycosylation in early mouse embryos. Biol Reprod 2009; 82:751-8. [PMID: 20032283 DOI: 10.1095/biolreprod.109.076661] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Maternal hyperglycemia is believed to be the metabolic derangement associated with both early pregnancy loss and congenital malformations in a diabetic pregnancy. Using an in vitro model of embryo exposure to hyperglycemia, this study questioned if increased flux through the hexosamine signaling pathway (HSP), which results in increased embryonic O-linked glycosylation (O-GlcNAcylation), underlies the glucotoxic effects of hyperglycemia during early embryogenesis. Mouse zygotes were randomly allocated to culture treatment groups that included no glucose (no flux through HSP), hyperglycemia (27 mM glucose, excess flux), 0.2 mM glucosamine (GlcN) in the absence of glucose (HSP flux alone), and O-GlcNAcylation levels monitored immunohistochemically. The impact of HSP manipulation on the first differentiation in development, blastocyst formation, was assessed, as were apoptosis and cell number in individual embryos. The enzymes regulating O-GlcNAcylation, and therefore hexosamine signaling, are the beta-linked-O-GlcNAc transferase (OGT) and an O-GlcNAc-selective beta-N-acetylglucosaminidase (O-GlcNAcase). Inhibition of these enzymes has a negative impact on blastocyst formation, demonstrating the importance of this signaling system to developmental potential. The ability of the OGT inhibitor benzyl-2-acetamido-2-deoxy-alpha-D-galactopyranoside (BADGP) to reverse the glucotoxic effects of hyperglycemia on these parameters was also sought. Excess HSP flux arising from a hyperglycemic environment or glucosamine supplementation reduced cell proliferation and blastocyst formation, confirming the criticality of this signaling pathway during early embryogenesis. Inhibition of OGT using BADGP blocked the negative impact of hyperglycemia on blastocyst formation, cell number, and apoptosis. Our results suggest that dysregulation of HSP and O-GlcNAcylation is the mechanism by which the embryotoxic effects of hyperglycemia are manifested during preimplantation development.
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Affiliation(s)
- Marie Pantaleon
- The University of Queensland School of Biomedical Sciences, Brisbane, Queensland 4072, Australia.
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Pantaleon M, Scott J, Kaye PL. Nutrient sensing by the early mouse embryo: hexosamine biosynthesis and glucose signaling during preimplantation development. Biol Reprod 2007; 78:595-600. [PMID: 18046015 DOI: 10.1095/biolreprod.107.062877] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Although mouse oocytes and cleavage-stage embryos are unable to utilize glucose as a metabolic fuel, they have a specific requirement for a short exposure to glucose prior to compaction. The reason for this requirement has been unclear. In this study we confirm that cleavage-stage exposure to glucose is required for blastocyst formation and show that the absence of glucose between 18-64 h after hCG causes an irreversible decrease in cellular proliferation and an increase in apoptosis. More importantly, this glucose signals to activate expression of Slc2a3 transcript and SLC2A3 protein, a facilitative glucose transporter (previously known as GLUT3) associated with developmental competence and increased glucose uptake used to fuel blastocyst formation. Glucosamine could substitute for glucose in these roles, suggesting that hexosamine biosynthesis may be a nutrient-sensing mechanism involved in metabolic differentiation. Inhibition of the rate-limiting enzyme in this pathway, glutamine-fructose-6-phosphate amidotransferase (GFPT), inhibited expression of the SLC2A3 transporter protein and blastocyst formation. Glucosamine, a substrate that enters this pathway downstream of GFPT, was able to overcome this inhibition and support SLC2A3 expression. These data suggest that early embryos rely on hexosamine biosynthesis as a glucose-sensing pathway to initiate metabolic differentiation.
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Affiliation(s)
- Marie Pantaleon
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, 4072 Australia.
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Józwik M, Józwik M, Teng C, Battaglia FC. Concentrations of monosaccharides and their amino and alcohol derivatives in human preovulatory follicular fluid. Mol Hum Reprod 2007; 13:791-6. [PMID: 17766681 DOI: 10.1093/molehr/gam060] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The study purpose was to compare sugar and polyol concentrations in preovulatory ovarian follicular fluid (FF) with those in the circulation. Samples of FF and peripheral venous blood were obtained after an overnight fast from 14 women attending an IVF program. High performance liquid chromatography measurements of seven polyols, two aminohexoses and four hexoses were the main outcome measures. Glucose concentrations in FF and plasma were 2781.26 +/- 205.64 and 4431.25 +/- 65.17 microM, respectively (P < 0.001). Mannose concentration in FF was 38.99 +/- 3.33 microM, significantly lower than plasma concentration (55.38 +/- 2.29 microM; P < 0.001). A concentration gradient from plasma to FF was also significant for glycerol (99.41 +/- 8.47 versus 74.32 +/- 6.54 microM; P < 0.002), galactose (31.69 +/- 1.58 versus 26.73 +/- 1.93 microM; P < 0.01) and galactosamine (11.49 +/- 0.69 versus 6.38 +/- 0.59 microM; P < 0.001). The plasma-to-FF concentration difference was greatest for glucose (1649.99 +/- 204.09 microM). There was a significant correlation between plasma and FF concentrations for galactose and glycerol. This study supports a substantial utilization of glucose by the oocyte/granulosa cells complex, and documents a significant concentration gradient from plasma to FF for glycerol, mannose, galactose and galactosamine. These plasma-FF differences may reflect both utilization of these carbohydrates by the cells of the preovulatory ovarian follicle and/or transport characteristics of these cells.
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Affiliation(s)
- Maciej Józwik
- Department of Gynecology, Medical University of Bialystok, Sklodowskiej 24 A, 15-276 Bialystok, Poland.
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Gutnisky C, Dalvit GC, Pintos LN, Thompson JG, Beconi MT, Cetica PD. Influence of hyaluronic acid synthesis and cumulus mucification on bovine oocyte in vitro maturation, fertilisation and embryo development. Reprod Fertil Dev 2007; 19:488-97. [PMID: 17394798 DOI: 10.1071/rd06134] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Accepted: 01/02/2007] [Indexed: 11/23/2022] Open
Abstract
During cumulus-oocyte complex (COC) maturation, cumulus expansion involves the deposition of mucoelastic compounds, especially hyaluronic acid, synthesised from glucose via the hexosamine biosynthesis pathway. The aim of the present study was to determine the effects of uridine monophosphate (UMP) and 6-diazo-5-oxo-L-norleucine (DON), inhibitors of hyaluronic acid synthesis, during bovine oocyte in vitro maturation (IVM) on cumulus expansion, glucose uptake, protein synthesis, cumulus cell number, meiotic maturation, cleavage rate and subsequent embryo development. A further aim of the study was to examine the effect of hyaluronic acid on sperm capacitation and acrosome reaction in relation to the capacity of COCs to be fertilised in vitro. A low correlation between glucose uptake and degree of cumulus expansion was observed. Total and partial inhibition of cumulus expansion was observed with DON and UMP, respectively, and was accompanied by a decrease in glucose uptake with DON. Total protein content and cumulus cell number per COC increased during IVM, but was unaffected by the presence of DON or UMP, as was oocyte meiotic maturation. Rates of cleavage and blastocyst development decreased in oocytes matured with DON and UMP, although this inhibition was reversed when the in vitro fertilisation (IVF) medium contained heparin. Hyaluronic acid induced capacitation and the acrosome reaction, and in IVF medium prevented the inhibition of cleavage and blastocyst development by DON in a similar fashion to heparin. Hyaluronic acid synthesis during cumulus mucification contributes to the penetration and fertilisation of bovine oocytes, most likely by facilitating the processes of capacitation and acrosome reaction. Mucification during IVM is independent of cumulus cell proliferation, COC protein content, oocyte meiotic maturation and subsequent developmental competence once fertilised.
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Affiliation(s)
- Cynthia Gutnisky
- Area of Biochemistry, School of Veterinary Sciences, University of Buenos Aires, Chorroarín 280, Buenos Aires C1427CWO, Argentina
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Gilchrist RB, Thompson JG. Oocyte maturation: Emerging concepts and technologies to improve developmental potential in vitro. Theriogenology 2007; 67:6-15. [PMID: 17092551 DOI: 10.1016/j.theriogenology.2006.09.027] [Citation(s) in RCA: 224] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Oocyte in vitro maturation (IVM) is an important reproductive technology that generates mature oocytes that are capable of supporting preimplantation embryo development and full development to term. There is great clinical and commercial incentive to improve the efficiency of the technology, however, progress has been slow over the past decade. A critical challenge is to understand what constitutes oocyte developmental competence and the mechanisms governing it. We have taken the approach of studying in detail oocyte-somatic cell interactions; including, oocyte-cumulus cell (CC) gap-junctional communication, and bidirectional paracrine signalling between the two cell types. It is becoming clear that, compared to oocytes matured in vivo, IVM oocytes undergo maturation prematurely as they are still in the process of acquiring developmental competence in vivo, and the molecular cascade reinitiating meiosis differs entirely to that in vivo. Attempts to enhance oocyte developmental competence by attenuating the spontaneous meiotic resumption of oocytes in vitro have been met with mixed success. Kinase inhibitors that prevent maturation-promoting factor activity have, in general, been ineffectual on promoting oocyte developmental potential post-IVM. In contrast, agents that modulate oocyte cAMP during IVM show greater potential, possibly as these compounds extend oocyte-CC gap-junctional communication. An important concept that is now emerging is that the oocyte secretes potent growth factors that regulate fundamental aspects of CC function and thereby determine the distinctive phenotype of the cumulus-oocyte complex. The capacity of an oocyte to regulate its own microenvironment by oocyte-secreted factors (OSFs) may constitute an important component of oocyte developmental competence. In support of this notion, we have recently demonstrated that supplementing IVM media with exogenous OSFs improves oocyte developmental potential, as evidenced by enhanced pre- and post-implantation embryo development.
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Affiliation(s)
- Robert B Gilchrist
- Research Centre for Reproductive Health, School of Paediatrics and Reproductive Health, Discipline of Obstetrics and Gynaecology, Medical School, University of Adelaide, Adelaide, Australia.
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Kimura K, Iwata H, Thompson JG. The effect of glucosamine concentration on the development and sex ratio of bovine embryos. Anim Reprod Sci 2006; 103:228-38. [PMID: 17198747 DOI: 10.1016/j.anireprosci.2006.12.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2006] [Revised: 12/11/2006] [Accepted: 12/12/2006] [Indexed: 10/23/2022]
Abstract
Glucosamine is a component of hyaluronic acid and an alternative substrate to glucose for the extracellular matrix synthesis of COCs. Its addition to an IVM medium reduces the glucose consumption of bovine COCs. Glucosamine is also metabolized to UDP-N-acetyl glucosamine (UDP-GlcNAc) via the hexosamine biosynthesis pathway and is utilized for O-linked glycosylation by the X-linked enzyme, O-linked GlcNAc transferase (OGT). Moreover, the inactivation of the second X chromosome in female embryos is influential in producing the sex ratio bias observed in vitro when embryos are cultured in the presence of glucose above 2.5mM. Accordingly, the aim of this study is to examine whether the presence of glucosamine during maturation or embryo culture causes a sex ratio bias in bovine blastocysts. Glucosamine was added to the medium in three different embryo developmental periods: in vitro maturation, the one-cell to eight-cell stage (before the maternal-zygotic transition, MZT), and the eight-cell to blastocyst stage (after MZT). When glucosamine was added during in vitro maturation, the developmental competence of oocytes was severely compromised. However, the sex ratio of embryos was not influenced. When glucosamine was added to embryo culture medium during development from one-cell to eight-cell stage (before MZT), it affected neither the development nor the sex ratio of bovine embryos. Finally, when glucosamine was added after MZT, the development rate of embryos was severely decreased, and the sex ratio was skewed toward males. Moreover, an inhibitor of OGT, benzyl-2-acetamido-2-deoxy-alpha-D-galactopyranoside (BADGP), negated the effect of glucosamine on the sex ratio when it was added to embryo culture medium from the eight-cell to blastocyst stage (after MZT). These results suggest that, like glucose, the supplementation of glucosamine into the medium skewed the sex ratio to males and that OGT, an X-linked enzyme, was involved in this phenomenon. Moreover, this effect of glucosamine was limited only to when it was present in the embryo culture medium after MZT.
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Affiliation(s)
- Koji Kimura
- National Institute of Livestock and Grassland Science, 768 Nasushiobara, Tochigi 329-2793, Japan.
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Mayes MA, Laforest MF, Guillemette C, Gilchrist RB, Richard FJ. Adenosine 5'-monophosphate kinase-activated protein kinase (PRKA) activators delay meiotic resumption in porcine oocytes. Biol Reprod 2006; 76:589-97. [PMID: 17167165 DOI: 10.1095/biolreprod.106.057828] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Adenosine monophosphate-activated kinase (PRKA) is a serine/threonine kinase that functions as a metabolic switch in a number of physiological functions. The present study was undertaken to assess the role of this kinase in nuclear maturation of porcine oocytes. RT-PCR and immunoblotting revealed the expression of the PRKAA1 subunit in granulosa cells, cumulus-oocyte complexes (COC), and denuded oocytes (DO). Porcine COC and DO contained transcripts that corresponded to the expected sizes of the designed primers for PRKAB1 and PRKAG1. The PRKAA2 subunit was detected in granulosa cells and COC, whereas the PRKAG3 subunit was not detected in granulosa cells, COC or DO, whereas it was detected in the heart. The PRKAA1 protein was detected in granulosa cells, COC, DO, and zona pellucida (ZP). In the presence of the pharmacological activator of PRKA 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranosyl 5'-monophosphate (ZMP), COC were transiently maintained in meiotic arrest in a fully reversible manner. This inhibitory effect was not observed in DO. Other known PRKA activators, 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR) and metformin, also blocked meiotic resumption in COC. In contrast to mouse oocytes, in which PRKA activators reverse the inhibitory effect of PDE3 inhibitors, this combination still blocked meiotic resumption in porcine COC. These results demonstrate that the meiotic resumption of porcine COC is transiently blocked by PRKA activators in a dose-dependent manner, and that this effect is dependent on PRKA activity in cumulus cells. The present study describes a new role for PRKA in regulating meiotic resumption in COC and strongly suggests that cumulus cells play an essential role in the control of porcine oocyte maturation through the PRKA metabolic switch.
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Affiliation(s)
- Mario A Mayes
- Centre de Recherche en Biologie de la Reproduction, Département des Sciences Animales, Faculté des Sciences de l'Agriculture et d'Alimentation, Université Laval, Québec, Canada G1K 7P4
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