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Feitosa WB, Lopes E, Visintin JA, Assumpção MEOD. Endoplasmic reticulum distribution during bovine oocyte activation is regulated by protein kinase C via actin filaments. J Cell Physiol 2020; 235:5823-5834. [PMID: 31960444 DOI: 10.1002/jcp.29516] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 01/08/2020] [Indexed: 02/02/2023]
Abstract
Fertilization-induced [Ca2+ ]i oscillations generally depend on the release of calcium ions from the endoplasmic reticulum (ER). Since ER is the main store of calcium ions, it plays an important role in oocyte fertilization. However, the mechanism of ER organization at oocyte activation is unknown. Here, we show that protein kinase C (PKC) is involved in ER distribution during bovine oocyte activation, but not involved in cell cycle resumption and spindle organization. Actin filaments were affected by PKC pharmacological inhibition. In addition, similar to PKC results, the actin-depolymerizing drug cytochalasin B affected the ER distribution during oocyte activation. Specifically, we have demonstrated that ER organization during bovine oocyte activation is regulated by PKC possibly through its action on actin filaments regulation. Taken together, the results presented here provide further information on the pathway involved in the regulation of ER organization during oocyte activation and new insight into the functional role of PKC and actin filaments during this process.
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Affiliation(s)
- Weber Beringui Feitosa
- Department of Animal Reproduction, College of Veterinary Medicine, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Everton Lopes
- Department of Animal Reproduction, College of Veterinary Medicine, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Jose Antonio Visintin
- Department of Animal Reproduction, College of Veterinary Medicine, University of Sao Paulo, Sao Paulo, SP, Brazil
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Sathanawongs A, Fujiwara K, Kato T, Hirose M, Kamoshita M, Wojcikiewicz RJH, Parys JB, Ito J, Kashiwazaki N. The effect of M-phase stage-dependent kinase inhibitors on inositol 1,4,5-trisphosphate receptor 1 (IP3 R1) expression and localization in pig oocytes. Anim Sci J 2015; 86:138-47. [PMID: 25187116 DOI: 10.1111/asj.12258] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 05/02/2014] [Indexed: 02/02/2023]
Abstract
At fertilization, inositol 1,4,5-trisphosphate receptor type 1 (IP3 R1) has a crucial role in Ca(2+) release in mammals. Expression levels, localization and phosphorylation of IP3 R1 are important for its function, but it still remains unclear which molecule(s) regulates IP3 R1 behavior in pig oocytes. We examined whether there was a difference in localization of IP3 R1 after in vitro or in vivo maturation of pig oocytes. In mouse oocytes, large clusters of IP3 R1 were formed in the cortex of the oocyte except in a ring-shaped band of cortex adjacent to the spindle. However, no such clusters of IP3 R1 were observed in pig oocytes and there was no difference in its localization between in vitro and in vivo matured oocytes. We next tried to clarify which factor(s) regulates IP3 R1 localization, phosphorylation and expression using M-phase stage-dependent kinase inhibitors. Our results show that treatments with roscovitine (p34(cdc2) kinase inhibitor) or U0126 (mitogen-activated protein kinase inhibitor) did not affect IP3 R1 expression or localization in pig oocytes, although the latter strongly inhibited phosphorylation. However, treatment with BI-2536, an inhibitor of polo-like kinase 1 (Plk1), dramatically decreased the expression level of IP3 R1 in pig oocytes in a dose-dependent manner. From these results, it is suggested that Plk1 is involved in the regulation of IP3 R1 expression in pig oocytes.
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Affiliation(s)
- Anucha Sathanawongs
- Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand; Laboratory of Animal Reproduction, Graduate School of Veterinary Sciences, Azabu University, Sagamihara, Japan
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Chemical activation in Rhinella arenarum oocytes: effect of dehydroleucodine (DhL) and its hydrogenated derivative (2H-DhL). ZYGOTE 2014; 23:924-32. [PMID: 25424172 DOI: 10.1017/s0967199414000641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Mature oocytes are arrested in metaphase II due to the presence of high levels of active maturation promoting factor (MPF). After fertilization, active MPF levels decline abruptly, enabling oocytes to complete meiosis II. One of the first and universal events of oocyte activation is an increase in cytosolic Ca2+ that would be responsible for MPF inactivation. Mature oocytes can also be activated by parthenogenetic activation. The aims of this work are to test the ability of dehydroleucodine (DhL) and its hydrogenated derivative 11,13-dihydro-dehydroleucodine (2H-DhL) to induce chemical activation in amphibian oocytes and to study the participation of calcium in the process. Results indicated that DhL and 2H-DhL induced oocyte activation in a dose-dependent manner. After 90 min of treatment, DhL 36 μM was able to induce 95% activation, while 2H-DhL 36 μM was less active, with only 40% activation. Our results suggest that DhL induced the inhibition of MPF activity, probably by an increase in intracellular Ca2+ concentration. Extracellular Ca2+ would not be significant, although Ca2+ release from intracellular stores is critical. In this sense, IP3Rs and RyRs were involved in the Ca2+ transient induced by lactones. In this species, RyRs appears to be the largest contributor to Ca2+ release in DhL-induced activation. Although more studies are needed on the mechanism of action through which these lactones induce oocyte activation in Rhinella arenarum, the results of this research provide interesting perspectives for the use of these lactones as chemical activators in in vitro fertilization and cloning.
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OHASHI Y, HOSHINO Y, TANEMURA K, SATO E. Distribution of protein disulfide isomerase during maturation of pig oocytes. Anim Sci J 2012; 84:15-22. [DOI: 10.1111/j.1740-0929.2012.01030.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
SummaryTransient increases in the concentration of cytosolic Ca2+ are essential for triggering egg activation events. Increased Ca2+ results from its rapid release from intracellular stores, mainly mediated by one or both intracellular calcium channels: the inositol trisphosphate receptor (IP3R) and the ryanodine receptor (RyR). Several regulatory pathways that tailor the response of these channels to the specific cell type have been proposed. Among its many modulatory actions, calcium can serve as an activator of a cytosolic phospholipase A2 (cPLA2), which releases arachidonic acid from phospholipids of the endoplasmic reticulum as well as from the nuclear envelope. Previous studies have suggested that arachidonic acid and/or its metabolites were able to modulate the activity of several ion channels. Based on these findings, we have studied the participation of the phospholipase A2 (PLA2) pathway in the process of Bufo arenarum oocyte activation and the interrelation between any of its metabolites and the ion channels involved in the calcium release from the intracellular reservoirs at fertilization. We found that addition of both melittin, a potent PLA2 activator, and arachidonic acid, the main PLA2 reaction metabolite, was able to induce activation events in a bell-shaped manner. Differential regulation of IP3Rs and RyRs by arachidonic acid and its products could explain melittin and arachidonic acid behaviour in Bufo arenarum egg activation. The concerted action of arachidonic acid and/or its metabolites could provide controlled mobilization of calcium from intracellular reservoirs and useful tools for understanding calcium homeostasis in eggs that express both types of receptors.
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Martín-Romero FJ, López-Guerrero AM, Álvarez IS, Pozo-Guisado E. Role of Store-Operated Calcium Entry During Meiotic Progression and Fertilization of Mammalian Oocytes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 295:291-328. [DOI: 10.1016/b978-0-12-394306-4.00014-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Rispoli LA, Lawrence JL, Payton RR, Saxton AM, Schrock GE, Schrick FN, Middlebrooks BW, Dunlap JR, Parrish JJ, Edwards JL. Disparate consequences of heat stress exposure during meiotic maturation: embryo development after chemical activation vs fertilization of bovine oocytes. Reproduction 2011; 142:831-43. [PMID: 21994359 DOI: 10.1530/rep-11-0032] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Consequences of heat stress exposure during the first 12 h of meiotic maturation differed depending on how and when bovine oocytes were activated. If heat-stressed oocytes underwent IVF at ~24 h, blastocyst development was less than for respective controls and similar to that obtained for nonheat-stressed oocytes undergoing IVF at 30 h (i.e. slightly aged). In contrast, if heat-stressed oocytes underwent chemical activation with ionomycin/6-dimethylaminopurine at 24 h, blastocyst development was not only higher than respective controls, but also equivalent to development obtained after activation of nonheat-stressed oocytes at 30 h. Developmental differences in chemically activated vs IVF-derived embryos were not related to fertilization failure or gross alterations in cytoskeletal components. Rather, ionomycin-induced calcium release and MAP kinase activity were less in heat-stressed oocytes. While underlying mechanisms are multifactorial, ability to obtain equivalent or higher development after parthenogenetic activation demonstrates that oocytes experiencing heat stress during the first 12 h of meiotic maturation have the necessary components to develop to the blastocyst stage, but fail to do so after fertilization.
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Affiliation(s)
- L A Rispoli
- Department of Animal Science, Institute of Agriculture, UT AgResearch, The University of Tennessee, Knoxville, Tennessee 37996-4574, USA
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Participation of inositol trisphosphate and ryanodine receptors in Bufo arenarum oocyte activation. ZYGOTE 2010; 19:171-80. [DOI: 10.1017/s0967199410000444] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SummaryCalcium is considered the most important second messenger at fertilization. Transient release from intracellular stores is modulated through both agonist-gated channels, IP3Rs and RyRs, which can be found individually or together depending on the oocyte species. Using the four commonly used compounds (thimerosal, caffeine, heparin and ruthenium red), we investigated the existence and interdependence of both IP3Rs and RyRs in mature Bufo arenarum oocytes. We found that caffeine, a well known specific RyRs agonist, was able to trigger oocyte activation in a dose-dependent manner. Microinjection of 10 mM caffeine showed 100% of oocytes exhibiting characteristic morphological criteria of egg activation. Ruthenium red, the specific RyR blocker, was able to inhibit oocyte activation induced either by sperm or caffeine. Our present findings provide the first reported evidence of the existence of RyR in frogs. We further explored the relationship between IP3Rs and RyRs in B. arenarum oocytes by exposing them to the agonists of one class after injecting a blocker of the other class of receptor. We found that thimerosal overcame the inhibitory effect of RyR on oocyte activation, indicating that IP3Rs function as independent receptors. In contrast, previous injection of heparin delayed caffeine-induced calcium release, revealing a relative dependence of RyRs on functional IP3Rs, probably through a CICR mechanism. Both receptors play a role in Ca2+ release mechanisms although their relative contribution to the activation process is unclear.
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Mann JS, Lowther KM, Mehlmann LM. Reorganization of the endoplasmic reticulum and development of Ca2+ release mechanisms during meiotic maturation of human oocytes. Biol Reprod 2010; 83:578-83. [PMID: 20610804 DOI: 10.1095/biolreprod.110.085985] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Oocyte maturation in rodents is characterized by a dramatic reorganization of the endoplasmic reticulum (ER) and an increase in the ability of an oocyte to release Ca(2+) in response to fertilization or inositol 1,4,5-trisphosphate (IP(3)). We examined if human oocytes undergo similar changes during cytoplasmic meiotic maturation both in vivo and in vitro. Immature, germinal vesicle (GV)-stage oocytes had a fine network of ER throughout the cortex and interior, whereas the ER in the in vivo-matured, metaphase II oocytes was organized in large (diameter, ∼2-3 μm) accumulations throughout the cortex and interior. Likewise, oocytes matured in vitro exhibited cortical and interior clusters with no apparent polarity in regard to the meiotic spindle. In vivo-matured oocytes contained approximately 1.5-fold the amount of IP(3) receptor protein and released significantly more Ca(2+) in response to IP(3) compared with GV-stage oocytes; however, oocytes matured in vitro did not contain more IP(3) receptor protein or release more Ca(2+) in response to IP(3) compared with GV-stage oocytes. These results show that at least one cytoplasmic change occurs during in vitro maturation of human oocytes that might be important for fertilization and subsequent embryonic development, but they suggest that a low developmental competence of in vitro-matured oocytes could be the result of deficiencies in the ability to release Ca(2+) at fertilization.
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Affiliation(s)
- Jessica S Mann
- Department of Cell Biology and Center for Advanced Reproductive Sciences, University of Connecticut Health Center, Farmington, Connecticut, USA
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Powell MD, Manandhar G, Spate L, Sutovsky M, Zimmerman S, Sachdev SC, Hannink M, Prather RS, Sutovsky P. Discovery of putative oocyte quality markers by comparative ExacTag proteomics. Proteomics Clin Appl 2010; 4:337-51. [PMID: 21137054 DOI: 10.1002/prca.200900024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 10/01/2009] [Accepted: 11/03/2009] [Indexed: 12/28/2022]
Abstract
PURPOSE Identification of the biomarkers of oocyte quality, and developmental and reprogramming potential is of importance to assisted reproductive technology in humans and animals. EXPERIMENTAL DESIGN PerkinElmer ExacTag™ Kit was used to label differentially proteins in pig oocyte extracts (oocyte proteome) and pig oocyte-conditioned in vitro maturation media (oocyte secretome) obtained with high- and low-quality oocytes. RESULTS We identified 16 major proteins in the oocyte proteome that were expressed differentially in high- versus low-quality oocytes. More abundant proteins in the high-quality oocyte proteome included kelch-like ECH-associated protein 1 (an adaptor for ubiquitin-ligase CUL3), nuclear export factor CRM1 and ataxia-telangiectasia mutated protein kinase. Dystrophin (DMD) was more abundant in low-quality oocytes. In the secretome, we identified 110 proteins, including DMD and cystic fibrosis transmembrane conductance regulator, two proteins implicated in muscular dystrophy and cystic fibrosis, respectively. Monoubiquitin was identified in the low-quality-oocyte secretome. CONCLUSIONS AND CLINICAL IMPLICATIONS A direct, quantitative proteomic analysis of small oocyte protein samples can identify potential markers of oocyte quality without the need for a large amount of total protein. This approach will be applied to discovery of non-invasive biomarkers of oocyte quality in assisted human reproduction and in large animal embryo transfer programs.
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Resende RR, Adhikari A, da Costa JL, Lorençon E, Ladeira MS, Guatimosim S, Kihara AH, Ladeira LO. Influence of spontaneous calcium events on cell-cycle progression in embryonal carcinoma and adult stem cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2009; 1803:246-60. [PMID: 19958796 DOI: 10.1016/j.bbamcr.2009.11.008] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 10/28/2009] [Accepted: 11/18/2009] [Indexed: 01/11/2023]
Abstract
Spontaneous Ca(2+) events have been observed in diverse stem cell lines, including carcinoma and mesenchymal stem cells. Interestingly, during cell cycle progression, cells exhibit Ca(2+) transients during the G(1) to S transition, suggesting that these oscillations may play a role in cell cycle progression. We aimed to study the influence of promoting and blocking calcium oscillations in cell proliferation and cell cycle progression, both in neural progenitor and undifferentiated cells. We also identified which calcium stores are required for maintaining these oscillations. Both in neural progenitor and undifferentiated cells calcium oscillations were restricted to the G1/S transition, suggesting a role for these events in progression of the cell cycle. Maintenance of the oscillations required calcium influx only through inositol 1,4,5-triphosphate receptors (IP(3)Rs) and L-type channels in undifferentiated cells, while neural progenitor cells also utilized ryanodine-sensitive stores. Interestingly, promoting calcium oscillations through IP(3)R agonists increased both proliferation and levels of cell cycle regulators such as cyclins A and E. Conversely, blocking calcium events with IP(3)R antagonists had the opposite effect in both undifferentiated and neural progenitor cells. This suggests that calcium events created by IP(3)Rs may be involved in cell cycle progression and proliferation, possibly due to regulation of cyclin levels, both in undifferentiated cells and in neural progenitor cells.
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Affiliation(s)
- R R Resende
- Department of Physics, Institute of Exact Sciences, Federal University of Minas Gerais, Belo Horizonte, MG 31270-901, Brazil.
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12
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Gómez-Fernández C, Pozo-Guisado E, Gañán-Parra M, Perianes MJ, Alvarez IS, Martín-Romero FJ. Relocalization of STIM1 in mouse oocytes at fertilization: early involvement of store-operated calcium entry. Reproduction 2009; 138:211-21. [PMID: 19470709 DOI: 10.1530/rep-09-0126] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Calcium waves represent one of the most important intracellular signaling events in oocytes at fertilization required for the exit from metaphase arrest and the resumption of the cell cycle. The molecular mechanism ruling this signaling has been described in terms of the contribution of intracellular calcium stores to calcium spikes. In this work, we considered the possible contribution of store-operated calcium entry (SOCE) to this signaling, by studying the localization of the protein STIM1 in oocytes. STIM1 has been suggested to play a key role in the recruitment and activation of plasma membrane calcium channels, and we show here that mature mouse oocytes express this protein distributed in discrete clusters throughout their periphery in resting cells, colocalizing with the endoplasmic reticulum marker calreticulin. However, immunolocalization of the endogenous STIM1 showed considerable redistribution over larger areas or patches covering the entire periphery of the oocyte during Ca(2+) store depletion induced with thapsigargin or ionomycin. Furthermore, pharmacological activation of endogenous phospholipase C induced a similar pattern of redistribution of STIM1 in the oocyte. Finally, fertilization of mouse oocytes revealed a significant and rapid relocalization of STIM1, similar to that found after pharmacological Ca(2+) store depletion. This particular relocalization supports a role for STIM1 and SOCE in the calcium signaling during early stages of fertilization.
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Affiliation(s)
- Carolina Gómez-Fernández
- Departamento de Biología Celular, Reproductive and Developmental Biology Group (ReDes), Universidad de Extremadura, Badajoz, Spain
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Boni R, Cocchia N, Silvestre F, Tortora G, Lorizio R, Tosti E. Juvenile and adult immature and in vitro matured ovine oocytes evaluated in relation to membrane electrical properties, calcium stores, IP3 sensitivity and apoptosis occurrence in cumulus cells. Mol Reprod Dev 2008; 75:1752-60. [PMID: 18404643 DOI: 10.1002/mrd.20921] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The analysis of differences between juvenile and adult oocytes may provide useful information on the acquisition of meiotic and developmental competence of the female gamete. In oocytes collected from either ewes or 40-day-old lambs, we evaluated membrane electrical properties, such as resting potential, conductance, activation ion currents, L-type Ca(2+) currents as well as calcium stores and IP3 sensitivity; in addition, the incidence of apoptosis in cumulus cells in these two age categories was compared. The analysis was carried out in oocytes both prior to and after in vitro maturation. Significant differences were found in all the examined parameters in relation to maturational stages whereas minor differences were recorded in relation to age of the donor. IP3 sensitivity strongly increased after in vitro maturation following a dose-dependent pattern from 1 to 500 micromol/L with a significant interaction (P < 0.01) between dose and maturational stage. The incidence of apoptosis in cumulus cells strongly increased after in vitro maturation and was greater in adult than in juvenile cumulus cells (39.2 +/- 5.8% vs. 21.9 +/- 3.5%; P < 0.01). In conclusion, all the examined parameters were greatly affected by the maturational stage, whereas minor differences were due to age-related oocyte quality, that is, at plasma membrane levels to conductance, activation current peaks and calcium currents, at cytosol level to calcium stores and IP3 sensitivity, and to incidence of apoptosis in cumulus cells. These parameters were compared with previous data in bovine to analyze oocyte quality in juvenile and adult individuals or between species.
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Affiliation(s)
- R Boni
- Departimento di Scienze delle Produzioni Animali, Università della Basilicata, Potenza, Italy.
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Hirohashi N, Harada K, Chiba K. Hormone-induced cortical maturation ensures the slow block to polyspermy and does not couple with meiotic maturation in starfish. Dev Biol 2008; 318:194-202. [DOI: 10.1016/j.ydbio.2008.03.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2007] [Revised: 03/17/2008] [Accepted: 03/18/2008] [Indexed: 10/22/2022]
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Boni R, Gualtieri R, Talevi R, Tosti E. Calcium and other ion dynamics during gamete maturation and fertilization. Theriogenology 2007; 68 Suppl 1:S156-64. [PMID: 17572483 DOI: 10.1016/j.theriogenology.2007.05.048] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Ion currents and cytosolic free calcium ([Ca(2+)](i)) elevations are crucial events in triggering the complex machinery involved in both gamete maturation and fertilization. Oocyte maturation is triggered by hormone signaling which causes ion currents and [Ca(2+)](i) increase. Extracellular calcium seems to be required for meiosis progression since: (i) calcium depletion in the maturation medium severely affects oocyte developmental competence; (ii) the activity of plasma membrane L-type Ca(2+) currents decreases during maturation; (iii) the exposure to verapamil, a specific Ca(2+) channel blocker, decreases in vitro maturation efficiency. In spermatozoa, maturation initiates inside the epididymis and ends in the female genital tract. During their journey through the female reproductive tract, sperm undergo a dramatic selection and capacitation achieving fertilization competence. Adhesion to the tubal epithelium extends sperm life through depression of [Ca(2+)](i) until capacitation signals trigger an [Ca(2+)](i) elevation followed by sperm release. At fertilization, egg-sperm interaction evokes well-described transient and almost simultaneous events: i.e., fertilization current, a change in resting potential, and an increase in free [Ca(2+)](i) concentration. These events, termed oocyte activation, are the direct consequence of sperm interaction via either activation of a receptor or entry of a sperm factor. The latter hypothesis has been recently supported by the discovery of PCLzeta, a sperm-specific isozyme triggering a dramatic [Ca(2+)](i) increase via inositol 1,4,5-trisphosphate (IP(3)) production. The course of ion currents and [Ca(2+)](i) transients during maturation and fertilization plays a pivotal role in correct embryo development.
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Affiliation(s)
- Raffaele Boni
- Dip Scienze delle Produzioni Animali, Università della, Basilicata, 85100 Potenza, Italy.
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Calcium and fertilization. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s0167-7306(06)41016-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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17
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Miyara F, Pesty A, Migne C, Djediat C, Huang XB, Dumont-Hassan M, Debey P, Lefèvre B. Spontaneous calcium oscillations and nuclear PLC-β1 in human GV oocytes. Mol Reprod Dev 2007; 75:392-402. [PMID: 17620288 DOI: 10.1002/mrd.20749] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Our aim was to investigate if human oocytes, like mouse oocytes, exhibit spontaneous Ca(2+) oscillations and nuclear translocation of PLC-beta1 prior to germinal vesicle breakdown (GVBD), and to correlate these events with the evolution of chromatin configuration as a landmark for the meiosis resumption kinetics. Human germinal vesicle (GV) oocytes were either loaded with Fluo-3 probe to record Ca(2+) signals or fixed for subsequent fluorescent labeling of both chromatin and PLC-beta1, and immunogold labeling of PLC-beta1. Here for the first time, we show that human oocytes at the GV-stage exhibit spontaneous Ca(2+) oscillations. Interestingly, only oocytes with a large diameter and characterized by a compact chromatin surrounding the nucleolus of the GV could reveal these kind of oscillations. We also observed a translocation of PLC-beta1 from the cytoplasm towards the nucleus during in vitro maturation of human oocytes. Spontaneous calcium oscillations and nuclear translocation of PLC-beta1 may reflect some degree of oocyte maturity. The impact of our results may be very helpful to understand and resolve many enigmatic problems usually encountered during the in vitro meiotic maturation of human GV oocytes.
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Affiliation(s)
- F Miyara
- INRA, UMR 1198, INRA Domaine de Vilvert, Jouy en Josas Cedex, France
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