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Kashir J, Mistry BV, Rajab MA, BuSaleh L, Abu-Dawud R, Ahmed HA, Alharbi S, Nomikos M, AlHassan S, Coskun S, Assiri AM. The mammalian sperm factor phospholipase C zeta is critical for early embryo division and pregnancy in humans and mice. Hum Reprod 2024; 39:1256-1274. [PMID: 38670547 PMCID: PMC11145019 DOI: 10.1093/humrep/deae078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 03/13/2024] [Indexed: 04/28/2024] Open
Abstract
STUDY QUESTION Are sperm phospholipase C zeta (PLCζ) profiles linked to the quality of embryogenesis and pregnancy? SUMMARY ANSWER Sperm PLCζ levels in both mouse and humans correlate with measures of ideal embryogenesis whereby minimal levels seem to be required to result in successful pregnancy. WHAT IS KNOWN ALREADY While causative factors underlying male infertility are multivariable, cases are increasingly associated with the efficacy of oocyte activation, which in mammals occurs in response to specific profiles of calcium (Ca2+) oscillations driven by sperm-specific PLCζ. Although sperm PLCζ abrogation is extensively linked with human male infertility where oocyte activation is deficient, less is clear as to whether sperm PLCζ levels or localization underlies cases of defective embryogenesis and failed pregnancy following fertility treatment. STUDY DESIGN, SIZE, DURATION A cohort of 54 couples undergoing fertility treatment were recruited at the assisted reproductive technology laboratory at the King Faisal Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia. The recruitment criteria for males was a minimum sperm concentration of 5×106 sperm/ml, while all female patients had to have at least five oocytes. Sperm PLCζ analysis was performed in research laboratories, while semen assessments were performed, and time-lapse morphokinetic data were obtained, in the fertility clinic as part of routine treatment. The CRISPR/Cas9 system was concurrently used to induce indels and single-nucleotide mutations within the Plcζ gene to generate strains of Plcζ mutant mice. Sperm PLCζ was evaluated using immunofluorescence and immunoblotting with an antibody of confirmed consistent specificity against PLCζ. PARTICIPANTS/MATERIALS, SETTING, METHODS We evaluated PLCζ profiles in sperm samples from 54 human couples undergoing fertility treatment in the context of time-lapse morphokinetic analysis of resultant embryos, correlating such profiles to pregnancy status. Concurrently, we generated two strains of mutant Plcζ mice using CRISPR/Cas9, and performed IVF with wild type (WT) oocytes and using WT or mutant Plcζ sperm to generate embryos. We also assessed PLCζ status in WT and mutant mice sperm in the context of time-lapse morphokinetic analysis and breeding outcomes. MAIN RESULTS AND THE ROLE OF CHANCE A significant (P ≤ 0.05) positive relationship was observed between both PLCζ relative fluorescence and relative density with the times taken for both the second cell division (CC2) (r = 0.26 and r = 0.43, respectively) and the third cell division (S2) (r = 0.26). Examination of localization patterns also indicated significant correlations between the presence or absence of sperm PLCζ and CC2 (r = 0.27 and r = -0.27, respectively; P ≤ 0.025). Human sperm PLCζ levels were at their highest in the ideal times of CC2 (8-12 h) compared to time ranges outside the ideal timeframe (<8 and >12 h) where levels of human sperm PLCζ were lower. Following assignment of PLCζ level thresholds, quantification revealed a significantly higher (P ≤ 0.05) rate of successful pregnancy in values larger than the assigned cut-off for both relative fluorescence (19% vs 40%, respectively) and relative density (8% vs 54%, respectively). Immunoblotting indicated a single band for PLCζ at 74 kDa in sperm from WT mice, while a single band was also observed in sperm from heterozygous of Plcζ mutant mouse sperm, but at a diminished intensity. Immunofluorescent analysis indicated the previously reported (Kashir et al., 2021) fluorescence patterns in WT sperm, while sperm from Plcζ mutant mice exhibited a significantly diminished and dispersed pattern at the acrosomal region of the sperm head. Breeding experiments indicated a significantly reduced litter size of mutant Plcζ male mice compared to WT mice, while IVF-generated embryos using sperm from mutant Plcζ mice exhibited high rates of polyspermy, and resulted in significantly reduced numbers of these embryos reaching developmental milestones. LIMITATIONS, REASONS FOR CAUTION The human population examined was relatively small, and should be expanded to examine a larger multi-centre cohort. Infertility conditions are often multivariable, and it was not possible to evaluate all these in human patients. However, our mutant Plcζ mouse experiments do suggest that PLCζ plays a significant role in early embryo development. WIDER IMPLICATIONS OF THE FINDINGS We found that minimal levels of PLCζ within a specific range were required for optimal early embryogenesis, correlating with increased pregnancy. Levels of sperm PLCζ below specific thresholds were associated with ineffective embryogenesis and lower pregnancy rates, despite eliciting successful fertilization in both mice and humans. To our knowledge, this represents the first time that PLCζ levels in sperm have been correlated to prognostic measures of embryogenic efficacy and pregnancy rates in humans. Our data suggest for the first time that the clinical utilization of PLCζ may stand to benefit not just a specific population of male infertility where oocyte activation is completely deficient (wherein PLCζ is completely defective/abrogated), but also perhaps the larger population of couples seeking fertility treatment. STUDY FUNDING/COMPETING INTEREST(S) J.K. is supported by a faculty start up grant awarded by Khalifa University (FSU-2023-015). This study was also supported by a Healthcare Research Fellowship Award (HF-14-16) from Health and Care Research Wales (HCRW) to J.K., alongside a National Science, Technology, and Innovation plan (NSTIP) project grant (15-MED4186-20) awarded by the King Abdulaziz City for Science and Technology (KACST) for J.K. and A.M.A. The authors declare no conflicts of interest. TRIAL REGISTRATION NUMBER N/A.
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Affiliation(s)
- Junaid Kashir
- Department of Biological Sciences, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates
- Center for Biotechnology, Khalifa University, Abu Dhabi, United Arab Emirates
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Bhavesh V Mistry
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Mohamed A Rajab
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Lujain BuSaleh
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Raed Abu-Dawud
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
- Institute for Molecular Medicine, MSH Medical School, Hamburg, Germany
| | - Hala A Ahmed
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Sarah Alharbi
- Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Michail Nomikos
- College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Saad AlHassan
- Department of Obstetrics and Gynaecology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Serdar Coskun
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
- Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Abdullah M Assiri
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
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Gonzalez-Castro RA, Carnevale EM. Phospholipase C Zeta 1 (PLCZ1): The Function and Potential for Fertility Assessment and In Vitro Embryo Production in Cattle and Horses. Vet Sci 2023; 10:698. [PMID: 38133249 PMCID: PMC10747197 DOI: 10.3390/vetsci10120698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/01/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023] Open
Abstract
Phospholipase C Zeta 1 (PLCZ1) is considered a major sperm-borne oocyte activation factor. After gamete fusion, PLCZ1 triggers calcium oscillations in the oocyte, resulting in oocyte activation. In assisted fertilization, oocyte activation failure is a major cause of low fertility. Most cases of oocyte activation failures in humans related to male infertility are associated with gene mutations and/or altered PLCZ1. Consequently, PLCZ1 evaluation could be an effective diagnostic marker and predictor of sperm fertilizing potential for in vivo and in vitro embryo production. The characterization of PLCZ1 has been principally investigated in men and mice, with less known about the PLCZ1 impact on assisted reproduction in other species, such as cattle and horses. In horses, sperm PLCZ1 varies among stallions, and sperm populations with high PLCZ1 are associated with cleavage after intracytoplasmic sperm injection (ICSI). In contrast, bull sperm is less able to initiate calcium oscillations and undergo nuclear remodeling, resulting in poor cleavage after ICSI. Advantageously, injections of PLCZ1 are able to rescue oocyte failure in mouse oocytes after ICSI, promoting full development and birth. However, further research is needed to optimize PLCZ1 diagnostic tests for consistent association with fertility and to determine whether PLCZ1 as an oocyte-activating treatment is a physiological, efficient, and safe method for improving assisted fertilization in cattle and horses.
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Affiliation(s)
| | - Elaine M. Carnevale
- Equine Reproduction Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA;
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Bafleh WS, Abdulsamad HMR, Al-Qaraghuli SM, El Khatib RY, Elbahrawi RT, Abdukadir AM, Alsawae SM, Dimassi Z, Hamdan H, Kashir J. Applications of advances in mRNA-based platforms as therapeutics and diagnostics in reproductive technologies. Front Cell Dev Biol 2023; 11:1198848. [PMID: 37305677 PMCID: PMC10250609 DOI: 10.3389/fcell.2023.1198848] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 05/18/2023] [Indexed: 06/13/2023] Open
Abstract
The recent COVID-19 pandemic led to many drastic changes in not only society, law, economics, but also in science and medicine, marking for the first time when drug regulatory authorities cleared for use mRNA-based vaccines in the fight against this outbreak. However, while indeed representing a novel application of such technology in the context of vaccination medicine, introducing RNA into cells to produce resultant molecules (proteins, antibodies, etc.) is not a novel principle. It has been common practice to introduce/inject mRNA into oocytes and embryos to inhibit, induce, and identify several factors in a research context, while such aspects have also been proposed as potential therapeutic and diagnostic applications to combat infertility in humans. Herein, we describe key areas where mRNA-based platforms have thus far represented potential areas of clinical applications, describing the advantages and limitations of such applications. Finally, we also discuss how recent advances in mRNA-based platforms, driven by the recent pandemic, may stand to benefit the treatment of infertility in humans. We also present brief future directions as to how we could utilise recent and current advancements to enhance RNA therapeutics within reproductive biology, specifically with relation to oocyte and embryo delivery.
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Affiliation(s)
- Wjdan S. Bafleh
- Department of Physiology and Immunology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Haia M. R. Abdulsamad
- Department of Physiology and Immunology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Sally M. Al-Qaraghuli
- Department of Physiology and Immunology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Riwa Y. El Khatib
- Department of Physiology and Immunology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Rawdah Taha Elbahrawi
- Department of Physiology and Immunology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Azhar Mohamud Abdukadir
- Department of Physiology and Immunology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates
| | | | - Zakia Dimassi
- Department of Pediatrics, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Hamdan Hamdan
- Department of Physiology and Immunology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates
- Healthcare Engineering Innovation Center (HEIC), Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Junaid Kashir
- Department of Biology, College of Arts and Science, Khalifa University, Abu Dhabi, United Arab Emirates
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
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Lin Y, Huang Y, Li B, Zhang T, Niu Y, Hu S, Ding Y, Yao G, Wei Z, Yao N, Yao Y, Lu Y, He Y, Zhu Q, Zhang L, Sun Y. Novel mutations in PLCZ1 lead to early embryonic arrest as a male factor. Front Cell Dev Biol 2023; 11:1193248. [PMID: 37261077 PMCID: PMC10227596 DOI: 10.3389/fcell.2023.1193248] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 05/05/2023] [Indexed: 06/02/2023] Open
Abstract
Early embryonic arrest is one of the causes of assist reproduction technology (ART) failure. We have previously reported that the first sperm-derived genetic factor, ACTL7a mutations, could lead to early embryonic arrest. However, whether there are other male genetic factors associated with early embryonic arrest remains elusive. Here, we reported bi-allelic mutations in PLCZ1, a well-known causal gene of total fertilization failure, in four infertile males. Among these mutations, p.403_404del, p.I489S, and p.W536X were newly reported in this study. Histological and Western blotting analysis of the patients' sperm indicated these variants as loss-of-function mutations. These patients manifested normal conventional semen parameters and ultra-structures in sperm heads. However, among four in vitro fertilization (IVF) cycles, 81.8% (18/22) of the oocytes were polyspermic fertilized, which was rarely reported in PLCZ1-related male patients. In the following six ICSI cycles, artificial oocyte activation (AOA) was applied and successfully rescued the fertilization failure and polyspermy phenotypes, with 31.3% (15/48) of the MII oocytes normally fertilized. However, 60.0% (9/15) of these normally fertilized zygotes were arrested at 2-5-cell stage, with one failing to cleave, indicating that PLCZ1 was not only necessary for fertilization, but also crucial for early embryonic development. However, these rescued zygotes showed a lower potential in developing into blastocysts when cultured in vitro. Thus, fresh cleavage transfer was tried and two live births were successfully achieved thereafter. In conclusion, this study provided novel mutations in PLCZ1 gene to expand the pathogenic mutational spectrum in male infertility and demonstrated that PLCZ1 was a crucial sperm-related genetic factor for early embryonic arrest. We also proposed that cleavage transfer after ICSI and AOA treatment could be a potential treatment method for male patients carrying bi-allelic mutations in PLCZ1.
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Affiliation(s)
- Yunying Lin
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
| | - Yi Huang
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
| | - Boyu Li
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
| | - Ting Zhang
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
| | - Yichao Niu
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
| | - Shuanggang Hu
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
| | - Ying Ding
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
| | - Guangxin Yao
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
| | - Zhe Wei
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
| | - Ning Yao
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
| | - Yejie Yao
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
| | - Yao Lu
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
| | - Yaqiong He
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
| | - Qinling Zhu
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
| | - Ling Zhang
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
| | - Yun Sun
- Center for Reproductive Medicine Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, China
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5
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The Therapeutic and Diagnostic Potential of Phospholipase C Zeta, Oocyte Activation, and Calcium in Treating Human Infertility. Pharmaceuticals (Basel) 2023; 16:ph16030441. [PMID: 36986540 PMCID: PMC10056371 DOI: 10.3390/ph16030441] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/19/2023] [Accepted: 03/06/2023] [Indexed: 03/17/2023] Open
Abstract
Oocyte activation, a fundamental event during mammalian fertilisation, is initiated by concerted intracellular patterns of calcium (Ca2+) release, termed Ca2+ oscillations, predominantly driven by testis-specific phospholipase C zeta (PLCζ). Ca2+ exerts a pivotal role in not just regulating oocyte activation and driving fertilisation, but also in influencing the quality of embryogenesis. In humans, a failure of Ca2+ release, or defects in related mechanisms, have been reported to result in infertility. Furthermore, mutations in the PLCζ gene and abnormalities in sperm PLCζ protein and RNA, have been strongly associated with forms of male infertility where oocyte activation is deficient. Concurrently, specific patterns and profiles of PLCζ in human sperm have been linked to parameters of semen quality, suggesting the potential for PLCζ as a powerful target for both therapeutics and diagnostics of human fertility. However, further to PLCζ and given the strong role played by Ca2+ in fertilisation, targets down- and up-stream of this process may also present a significantly similar level of promise. Herein, we systematically summarise recent advancements and controversies in the field to update expanding clinical associations between Ca2+-release, PLCζ, oocyte activation and human fertility. We discuss how such associations may potentially underlie defective embryogenesis and recurrent implantation failure following fertility treatments, alongside potential diagnostic and therapeutic avenues presented by oocyte activation for the diagnosis and treatment of human infertility.
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Kashir J, Mistry BV, BuSaleh L, Nomikos M, Almuqayyil S, Abu-Dawud R, AlYacoub N, Hamdan H, AlHassan S, Lai FA, Assiri AM, Coskun S. Antigen Unmasking Is Required to Clinically Assess Levels and Localisation Patterns of Phospholipase C Zeta in Human Sperm. Pharmaceuticals (Basel) 2023; 16:198. [PMID: 37259347 PMCID: PMC9962097 DOI: 10.3390/ph16020198] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/15/2023] [Accepted: 01/17/2023] [Indexed: 01/10/2024] Open
Abstract
Mammalian oocyte activation is initiated by intracellular calcium (Ca2+) oscillations, driven by the testis-specific phospholipase C zeta (PLCζ). Sperm PLCζ analysis represents a diagnostic measure of sperm fertilisation capacity. The application of antigen unmasking/retrieval (AUM) generally enhanced the visualisation efficacy of PLCζ in mammalian sperm, but differentially affected the PLCζ profiles in sperm from different human males. It is unclear whether AUM affects the diagnosis of PLCζ in human sperm. Herein, we examined whether the application of AUM affected the correlation of PLCζ profiles with sperm parameters and fertilisation capacity. PLCζ fluorescence levels and localisation patterns were examined within the sperm of males undergoing fertility treatment (55 patients aged 29-53) using immunofluorescence in the absence/presence of AUM. The changes in PLCζ profiles following AUM were examined in relation to sperm health and fertilisation outcome. AUM enhanced the observable levels and specific localisation patterns of PLCζ in relation to both optimal sperm parameters and fertilisation outcome, without which significant differences were not observed. The extent of the change in levels and localisation ratios of PLCζ was also affected to a larger degree in terms of the optimal parameters of sperm fertility and fertilisation capacity by AUM. Collectively, AUM was essential to accurately assesses PLCζ in human sperm in both scientific and clinical contexts.
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Affiliation(s)
- Junaid Kashir
- Department of Biology, College of Arts and Sciences, Khalifa University, Abu Dhabi 127788, United Arab Emirates
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11564, Saudi Arabia
| | - Bhavesh V. Mistry
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11564, Saudi Arabia
| | - Lujain BuSaleh
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11564, Saudi Arabia
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia
| | - Michail Nomikos
- College of Medicine, QU Health, Qatar University, Doha 2713, Qatar
| | - Sarah Almuqayyil
- Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11564, Saudi Arabia
| | - Raed Abu-Dawud
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11564, Saudi Arabia
| | - Nadya AlYacoub
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11564, Saudi Arabia
| | - Hamdan Hamdan
- Department of Physiology and Immunology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi 127788, United Arab Emirates
| | - Saad AlHassan
- Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11564, Saudi Arabia
- Department of Obstetrics and Gynecology, King Faisal Specialist Hospital and Research Centre, Riyadh 11564, Saudi Arabia
| | - F. Anthony Lai
- College of Medicine, QU Health, Qatar University, Doha 2713, Qatar
| | - Abdullah M. Assiri
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11564, Saudi Arabia
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia
| | - Serdar Coskun
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia
- Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11564, Saudi Arabia
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Shafqat A, Kashir J, Alsalameh S, Alkattan K, Yaqinuddin A. Fertilization, Oocyte Activation, Calcium Release and Epigenetic Remodelling: Lessons From Cancer Models. Front Cell Dev Biol 2022; 10:781953. [PMID: 35309905 PMCID: PMC8931327 DOI: 10.3389/fcell.2022.781953] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 02/14/2022] [Indexed: 12/11/2022] Open
Abstract
Oocyte activation deficiency (OAD) is the basis of Total Fertilisation Failure (TFF) and is attributed to mutations in the PLCζ gene—termed male factor infertility. This derives abnormal Ca2+ oscillations and could be the main cause of primary disruptions in the gene expression of Ca2+-related proteins. Epigenetic mechanisms are universally accepted as key regulators of gene expression. However, epigenetic dysregulations have not been considered as potential mechanisms of oocyte-borne OAD. Herein, we discuss changes in the DNA methylome during oogenesis and embryogenesis. We further highlight key pathways comprising the oocyte Ca2+ toolkit, which could be targets of epigenetic alterations, especially aberrations in DNA methylation. Considering that the vast majority of epigenetic modifications examined during fertilization revolve around alterations in DNA methylation, we aim in this article to associate Ca2+-specific mechanisms with these alterations. To strengthen this perspective, we bring evidence from cancer research on the intricate link between DNA methylation and Ca2+ signaling as cancer research has examined such questions in a lot more detail. From a therapeutic standpoint, if our hypothesis is proven to be correct, this will explain the cause of TFF in idiopathic cases and will open doors for novel therapeutic targets.
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Affiliation(s)
- Areez Shafqat
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Junaid Kashir
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | | | - Khaled Alkattan
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Ahmed Yaqinuddin
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
- *Correspondence: Ahmed Yaqinuddin,
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Kashir J, Ganesh D, Jones C, Coward K. OUP accepted manuscript. Hum Reprod Open 2022; 2022:hoac003. [PMID: 35261925 PMCID: PMC8894871 DOI: 10.1093/hropen/hoac003] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/16/2022] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Oocyte activation deficiency (OAD) is attributed to the majority of cases underlying failure of ICSI cycles, the standard treatment for male factor infertility. Oocyte activation encompasses a series of concerted events, triggered by sperm-specific phospholipase C zeta (PLCζ), which elicits increases in free cytoplasmic calcium (Ca2+) in spatially and temporally specific oscillations. Defects in this specific pattern of Ca2+ release are directly attributable to most cases of OAD. Ca2+ release can be clinically mediated via assisted oocyte activation (AOA), a combination of mechanical, electrical and/or chemical stimuli which artificially promote an increase in the levels of intra-cytoplasmic Ca2+. However, concerns regarding safety and efficacy underlie potential risks that must be addressed before such methods can be safely widely used. OBJECTIVE AND RATIONALE Recent advances in current AOA techniques warrant a review of the safety and efficacy of these practices, to determine the extent to which AOA may be implemented in the clinic. Importantly, the primary challenges to obtaining data on the safety and efficacy of AOA must be determined. Such questions require urgent attention before widespread clinical utilization of such protocols can be advocated. SEARCH METHODS A literature review was performed using databases including PubMed, Web of Science, Medline, etc. using AOA, OAD, calcium ionophores, ICSI, PLCζ, oocyte activation, failed fertilization and fertilization failure as keywords. Relevant articles published until June 2019 were analysed and included in the review, with an emphasis on studies assessing large-scale efficacy and safety. OUTCOMES Contradictory studies on the safety and efficacy of AOA do not yet allow for the establishment of AOA as standard practice in the clinic. Heterogeneity in study methodology, inconsistent sample inclusion criteria, non-standardized outcome assessments, restricted sample size and animal model limitations render AOA strictly experimental. The main scientific concern impeding AOA utilization in the clinic is the non-physiological method of Ca2+ release mediated by most AOA agents, coupled with a lack of holistic understanding regarding the physiological mechanism(s) underlying Ca2+ release at oocyte activation. LIMITATIONS, REASONS FOR CAUTION The number of studies with clinical relevance using AOA remains significantly low. A much wider range of studies examining outcomes using multiple AOA agents are required. WIDER IMPLICATIONS In addition to addressing the five main challenges of studies assessing AOA safety and efficacy, more standardized, large-scale, multi-centre studies of AOA, as well as long-term follow-up studies of children born from AOA, would provide evidence for establishing AOA as a treatment for infertility. The delivery of an activating agent that can more accurately recapitulate physiological fertilization, such as recombinant PLCζ, is a promising prospect for the future of AOA. Further to PLCζ, many other avenues of physiological oocyte activation also require urgent investigation to assess other potential physiological avenues of AOA. STUDY FUNDING/COMPETING INTERESTS D.G. was supported by Stanford University’s Bing Overseas Study Program. J.K. was supported by a Healthcare Research Fellowship Award (HF-14-16) made by Health and Care Research Wales (HCRW), alongside a National Science, Technology, and Innovation plan (NSTIP) project grant (15-MED4186-20) awarded by the King Abdulaziz City for Science and Technology (KACST). The authors have no competing interests to declare.
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Affiliation(s)
| | | | - Celine Jones
- Nuffield Department of Women’s & Reproductive Health, University of Oxford, Level 3, Women’s Centre, John Radcliffe Hospital, Oxford, UK
| | - Kevin Coward
- Correspondence address. Nuffield Department of Women’s & Reproductive Health, University of Oxford, Level 3, Women’s Centre, John Radcliffe Hospital, Oxford, OS3 9DU, UK. E-mail: https://orcid.org/0000-0003-3577-4041
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9
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Wang M, Zhu L, Liu C, He H, Wang C, Xing C, Liu J, Yang L, Xi Q, Li Z, Jin L. A Novel Assisted Oocyte Activation Method Improves Fertilization in Patients With Recurrent Fertilization Failure. Front Cell Dev Biol 2021; 9:672081. [PMID: 34368125 PMCID: PMC8334862 DOI: 10.3389/fcell.2021.672081] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 06/21/2021] [Indexed: 11/23/2022] Open
Abstract
Total fertilization failure (TFF) occurs in 1–3% of total intracytoplasmic sperm injection (ICSI) cycles and can reoccur in subsequent cycles. Despite the high success rate with the application of assisted oocyte activation (AOA), there is still a small number of couples who cannot obtain fertilized eggs after conventional calcium (Ca2+) ionophores-based ICSI-AOA. Six couples experiencing repeated TFF or low fertilization (<10%) after ICSI and conventional ICSI-AOA were enrolled in this study. Compared with the regular ICSI group and the conventional ICSI-AOA group, the new AOA method, a combination of cycloheximide (CHX) and ionomycin, can significantly increase the fertilization rate from less than 10 up to approximately 50% in most cases. The normal distribution of sperm-related oocyte activation factor phospholipase C zeta (PLCζ1) in the sperms of the cases indicated the absence of an aberrant Ca2+ signaling activation. The results of the whole-embryo aneuploidies analysis indicated that oocytes receiving the novel AOA treatment had the potential to develop into blastocysts with normal karyotypes. Our data demonstrated that CHX combined with ionomycin was able to effectively improve the fertilization rate in the majority of patients suffering from TFF. This novel AOA method had a potential therapeutic effect on those couples experiencing TFF, even after conventional AOA, which may surmount the severe fertilization deficiencies in patients with a repeated low fertilization or TFF.
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Affiliation(s)
- Meng Wang
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lixia Zhu
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chang Liu
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hui He
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Cheng Wang
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chenxi Xing
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jinming Liu
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Liu Yang
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qingsong Xi
- Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhou Li
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lei Jin
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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10
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Yan Z, Fan Y, Wang F, Yan Z, Li M, Ouyang J, Wu L, Yin M, Zhao J, Kuang Y, Li B, Lyu Q. Novel mutations in PLCZ1 cause male infertility due to fertilization failure or poor fertilization. Hum Reprod 2021; 35:472-481. [PMID: 32048714 DOI: 10.1093/humrep/dez282] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 12/03/2019] [Indexed: 12/20/2022] Open
Abstract
STUDY QUESTION Do sperm-specific phospholipase C zeta (PLCZ1) mutations account for male infertility due to fertilization failure? SUMMARY ANSWER Six novel mutations and one reported mutation in PLCZ1 were identified in five of 14 independent families characterized by fertilization failure or poor fertilization, suggesting that these mutations may be responsible for fertilization failure in men exhibiting primary infertility. WHAT IS KNOWN ALREADY PLCZ1 is essential for the induction of intracellular calcium (Ca2+) oscillations and the initiation of oocyte activation during mammalian fertilization. However, genetic evidence linking PLCZ1 mutations with male infertility remains limited. STUDY DESIGN, SIZE, DURATION Fourteen unrelated primary infertility patients were recruited into this study from January 2016 to December 2018; the patients exhibited total fertilization failure or poor fertilization, as evidenced by ICSI and sperm-related oocyte activation deficiencies identified in mouse oocyte activation assays. PARTICIPANTS/MATERIALS, SETTING, METHODS Genomic DNA samples were extracted from the peripheral blood of patients. The whole exons of PLCZ1 were sequenced by Sanger sequencing. The PLCZ1 sequences were aligned by CodonCode software to identify rare variants. The ExAC database was used to search for the frequency of corresponding mutations. The pathogenicity of identified variants and their possible effects on the protein were assessed in silico. PLCZ1 protein levels in semen samples were evaluated by western blotting. Oocyte activation ability was assessed by the injection of wild-type and mutant PLCZ1 cRNAs into human mature metaphase II (MII) oocytes in vitro. MAIN RESULTS AND THE ROLE OF CHANCE We identified six novel mutations and one reported mutation in PLCZ1 among five affected individuals. In addition to four novel missense mutations, two new types of genetic variants were identified, including one in-frame deletion and one splicing mutation. Western blot analysis revealed that PLCZ1 protein expression was not observed in the semen samples from the five affected patients. Microinjection with the PLCZ1 cRNA variants was performed, and a significant decrease in the percentage of pronuclei was observed for four novel missense mutations and one novel in-frame deletion mutation, suggesting that these mutations have a deleterious influence on protein function. By artificial oocyte activation treatment, the fertilization failure phenotypes of four affected patients were successfully rescued and three healthy babies were delivered. LARGE SCALE DATA N/A. LIMITATIONS, REASONS FOR CAUTION We screened only the whole exons of PLCZ1. Additional possible mutations in the non-coding region of PLCZ1 should be further studied. WIDER IMPLICATIONS OF THE FINDINGS Our study not only further confirms the important role of PLCZ1 in human fertilization but also expands the mutational spectrum of PLCZ1 associated with male infertility, which provides a basis for assessing genetic variation in PLCZ1 as a potential diagnostic marker for infertile men suffering from fertilization failure. STUDY FUNDING/COMPETING INTEREST(S) This research was supported by the National Natural Foundation of China (81 571 486 and 81 771 649). All authors have no conflicts of interest to declare.
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Affiliation(s)
- Zheng Yan
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, People's Republic of China
| | - Yong Fan
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, People's Republic of China
| | - Fei Wang
- College of Medicine, Anhui University of Science and Technology, Huainan 232000, People's Republic of China
| | - Zhiguang Yan
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, People's Republic of China
| | - Menghui Li
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, People's Republic of China
| | - Jie Ouyang
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, People's Republic of China
| | - Ling Wu
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, People's Republic of China
| | - Mingru Yin
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, People's Republic of China
| | - Jilang Zhao
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, People's Republic of China
| | - Yanping Kuang
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, People's Republic of China
| | - Bin Li
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, People's Republic of China
| | - Qifeng Lyu
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, People's Republic of China
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11
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Unnikrishnan V, Kastelic JP, Thundathil JC. Ouabain-induced activation of phospholipase C zeta and its contributions to bovine sperm capacitation. Cell Tissue Res 2021; 385:785-801. [PMID: 33885964 DOI: 10.1007/s00441-021-03455-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 03/22/2021] [Indexed: 11/30/2022]
Abstract
The sperm-derived oocyte activating factor, phospholipase C zeta (PLC ζ), is the only PLC isoform reported in cattle. The objectives were to (1) localize PLC ζ in fresh and capacitated bovine sperm and (2) investigate the activation of PLC ζ during bull sperm capacitation and contributions of PLC activity to this process. We confirmed interaction of testis-specific isoform of Na/K-ATPase (ATP1A4) with PLC ζ (immunolocalization and immunoprecipitation) and tyrosine phosphorylation (immunoprecipitation) of PLC ζ (a post-translational protein modification commonly involved in activation of PLC in somatic cells) during capacitation. Furthermore, incubation of sperm under capacitating conditions upregulated PLC-mediated hyperactivated motility, tyrosine phosphoprotein content, acrosome reaction, and F-actin formation (flow cytometry), implying that PLC activity is enhanced during capacitation and contributing to these capacitation processes. In conclusion, we inferred that PLC ζ is activated during capacitation by tyrosine phosphorylation through a mechanism involving ATP1A4, contributing to capacitation-associated biochemical events.
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Affiliation(s)
- Veena Unnikrishnan
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, CAL, T2N 4N1, Canada
| | - John P Kastelic
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, CAL, T2N 4N1, Canada
| | - Jacob C Thundathil
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, CAL, T2N 4N1, Canada.
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12
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Meng X, Melo P, Jones C, Ross C, Mounce G, Turner K, Child T, Coward K. Use of phospholipase C zeta analysis to identify candidates for artificial oocyte activation: a case series of clinical pregnancies and a proposed algorithm for patient management. Fertil Steril 2021; 114:163-174. [PMID: 32622408 DOI: 10.1016/j.fertnstert.2020.02.113] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 01/31/2020] [Accepted: 02/28/2020] [Indexed: 12/19/2022]
Abstract
OBJECTIVE To investigate the applicability of phospholipase C zeta (PLCζ) analysis in assisting the clinical decision-making process when considering artificial oocyte activation (AOA) for infertile males in assisted reproductive technology. DESIGN Fifty-six males (43 infertile/13 fertile) were screened using our PLCζ assay. SETTING Fertility unit/university laboratory. PATIENT(S) Infertile males with abnormal sperm morphology or total fertilization failure, low fertilization rate (<50%), or repeated fertilization failure in assisted reproductive technology. INTERVENTION(S) We analyzed PLCζ levels in sperm from fertile and infertile males. Eligible patients subsequently underwent intracytoplasmic sperm injection (ICSI)/artificial oocyte activation (AOA) with calcimycin (GM508). MAIN OUTCOME MEASURE(S) PLCζ localization and level and the proportion of sperm expressing PLCζ. Thresholds of PLCζ deficiency, fertilization rates, pregnancy rates, and live birth rates of AOA and non-AOA cycles. RESULT(S) Compared with 13 fertile controls, 34 of the 43 infertile males had significantly lower levels of PLCζ and/or a significantly lower proportion of sperm exhibiting PLCζ. Of these 34 patients, 15 showed a significant PLCζ reduction in both parameters, which we termed "PLCζ deficiency." Five PLCζ-deficient patients opted for AOA; all five achieved fertilization, and four achieved clinical pregnancies and live births. The fertilization rate improved significantly from 18.6% (ICSI) to 56.8% (ICSI/AOA). The clinical pregnancy rate and live birth rate with AOA were both 40% per initiated cycle. Youden index analysis revealed that the cutoffs below which infertile males were likely to benefit from AOA were 71% for the proportion of sperm expressing PLCζ and 15.57 arbitrary units for mean PLCζ level. CONCLUSION(S) PLCζ analysis is a useful diagnostic tool to determine patient eligibility for subsequent AOA treatment.
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Affiliation(s)
- Xin Meng
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom
| | - Pedro Melo
- The Women's Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Celine Jones
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom
| | | | - Ginny Mounce
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom
| | - Karen Turner
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom; Oxford Fertility, Oxford, United Kingdom
| | - Tim Child
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom; Oxford Fertility, Oxford, United Kingdom
| | - Kevin Coward
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom.
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13
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Zafar MI, Lu S, Li H. Sperm-oocyte interplay: an overview of spermatozoon's role in oocyte activation and current perspectives in diagnosis and fertility treatment. Cell Biosci 2021; 11:4. [PMID: 33407934 PMCID: PMC7789549 DOI: 10.1186/s13578-020-00520-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 12/15/2020] [Indexed: 02/07/2023] Open
Abstract
The fertilizing spermatozoon is a highly specialized cell that selects from millions along the female tract until the oocyte. The paternal components influence the oocyte activation during fertilization and are fundamental for normal embryo development; however, the sperm-oocyte interplay is in a continuous debate. This review aims to analyze the available scientific information related to the role of the male gamete in the oocyte activation during fertilization, the process of the interaction of sperm factors with oocyte machinery, and the implications of any alterations in this interplay, as well as the advances and limitations of the reproductive techniques and diagnostic tests. At present, both PLCζ and PAWP are the main candidates as oocyte activated factors during fertilization. While PLCζ mechanism is via IP3, how PAWP activates the oocyte still no clear, and these findings are important to study and treat fertilization failure due to oocyte activation, especially when one of the causes is the deficiency of PLCζ in the sperm. However, no diagnostic test has been developed to establish the amount of PLCζ, the protocol to treat this type of pathologies is broad, including treatment with ionophores, sperm selection improvement, and microinjection with PLCζ protein or RNA.
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Affiliation(s)
- Mohammad Ishraq Zafar
- Institute of Reproductive Health/Center of Reproductive Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hang Kong Road, Wuhan, 430030, People's Republic of China
| | - Shi Lu
- Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jeifang Avenue, Wuhan, 430022, People's Republic of China
| | - Honggang Li
- Institute of Reproductive Health/Center of Reproductive Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hang Kong Road, Wuhan, 430030, People's Republic of China. .,Wuhan Tongji Reproductive Medicine Hospital, 128 Sanyang Road, Wuhan, 430013, People's Republic of China.
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14
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Diagnosis and Treatment of Male Infertility-Related Fertilization Failure. J Clin Med 2020; 9:jcm9123899. [PMID: 33271815 PMCID: PMC7761017 DOI: 10.3390/jcm9123899] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 11/26/2020] [Accepted: 11/27/2020] [Indexed: 12/22/2022] Open
Abstract
Infertility affects approximately 15% of reproductive-aged couples worldwide, of which up to 30% of the cases are caused by male factors alone. The origin of male infertility is mostly attributed to sperm abnormalities, of which many are caused by genetic defects. The development of intracytoplasmic sperm injection (ICSI) has helped to circumvent most male infertility conditions. However, there is still a challenging group of infertile males whose sperm, although having normal sperm parameters, are unable to activate the oocyte, even after ICSI treatment. While ICSI generally allows fertilization rates of 70 to 80%, total fertilization failure (FF) still occurs in 1 to 3% of ICSI cycles. Phospholipase C zeta (PLCζ) has been demonstrated to be a critical sperm oocyte activating factor (SOAF) and the absence, reduced, or altered forms of PLCζ have been shown to cause male infertility-related FF. The purpose of this review is to (i) summarize the current knowledge on PLCζ as the critical sperm factor for successful fertilization, as well as to discuss the existence of alternative sperm-induced oocyte activation mechanisms, (ii) describe the diagnostic tests available to determine the cause of FF, and (iii) summarize the beneficial effect of assisted oocyte activation (AOA) to overcome FF.
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15
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Torra-Massana M, Cornet-Bartolomé D, Barragán M, Durban M, Ferrer-Vaquer A, Zambelli F, Rodriguez A, Oliva R, Vassena R. Novel phospholipase C zeta 1 mutations associated with fertilization failures after ICSI. Hum Reprod 2020; 34:1494-1504. [PMID: 31347677 DOI: 10.1093/humrep/dez094] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/03/2019] [Indexed: 12/20/2022] Open
Abstract
STUDY QUESTION Are phospholipase C zeta 1 (PLCZ1) mutations associated with fertilization failure (FF) after ICSI? SUMMARY ANSWER New mutations in the PLCZ1 sequence are associated with FFs after ICSI. WHAT IS KNOWN ALREADY FF occurs in 1-3% of ICSI cycles, mainly due to oocyte activation failure (OAF). The sperm PLCζ/PLCZ1 protein hydrolyzes phosphatidylinositol (4, 5)-bisphosphate in the oocyte, leading to intracellular calcium release and oocyte activation. To date, few PLCZ1 point mutations causing decreased protein levels or activity have been linked to FF. However, functional alterations of PLCζ/PLCZ1 in response to both described and novel mutations have not been investigated. STUDY DESIGN, SIZE, DURATION We performed a study including 37 patients presenting total or partial FF (fertilization rate (FR), ≤25%) after ICSI occurring between 2014 and 2018. PARTICIPANTS/MATERIALS, SETTING, METHODS Patients were divided into two groups based on oocyte evaluation 19 h post ICSI: FF due to a defect in oocyte activation (OAF, n = 22) and FF due to other causes ('no-OAF', n = 15). Samples from 13 men with good fertilization (FR, >50%) were used as controls. PLCζ/PLCZ1 protein localization and levels in sperm were evaluated by immunofluorescence and western blot, respectively. Sanger sequencing on genomic DNA was used to identify PLCZ1 mutations in exonic regions. The effect of the mutations on protein functionality was predicted in silico using the MODICT algorithm. Functional assays were performed by cRNA injection of wild-type and mutated forms of PLCZ1 into human in vitro matured metaphase II oocytes, and fertilization outcomes (second polar body extrusion, pronucleus appearance) scored 19 h after injection. MAIN RESULTS AND THE ROLE OF CHANCE In the OAF group, 12 (54.6%) patients carried at least one mutation in the PLCZ1 coding sequence, one patient out of 15 (6.7%) in the no-OAF group (P < 0.05) and none of the 13 controls (P < 0.05). A total of six different mutations were identified. Five of them were single-nucleotide missense mutations: p.I120M, located at the end of the EF-hand domain; p.R197H, p.L224P and p.H233L, located at the X catalytic domain; and p.S500 L, located at the C2 domain. The sixth mutation, a frameshift variant (p.V326K fs*25), generates a truncated protein at the X-Y linker region. In silico analysis with MODICT predicted all the mutations except p.I120M to be potentially deleterious for PLCζ/PLCZ1 activity. After PLCZ1 cRNA injection, a significant decrease in the percentage of activated oocytes was observed for three mutations (p.R197H, p.H233L and p.V326K fs*25), indicating a deleterious effect on enzymatic activity. PLCZ1 protein localization and expression levels in sperm were similar across groups. FRs were restored (to >60%) in patients carrying PLCZ1 mutations (n = 10) after assisted oocyte activation (AOA), with seven patients achieving pregnancy and live birth. LIMITATIONS, REASONS FOR CAUTION Caution should be exerted when comparing the cRNA injection results with fertilization outcomes after ICSI, especially in patients presenting mutations in heterozygosis. WIDER IMPLICATIONS OF THE FINDINGS PLCZ1 mutations were found in high frequency in patients presenting OAF. Functional analysis of three mutations in human oocytes confirms alteration of PLCζ/PLCZ1 activity and their likely involvement in impaired oocyte activation. Our results suggest that PLCZ1 gene sequencing could be useful as a tool for the diagnosis and counseling of couples presenting FF after ICSI due to OAF. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by intramural funding of Clínica EUGIN, by the Secretary for Universities and Research of the Ministry of Economy and Knowledge of the Government of Catalonia (GENCAT 2015 DI 049 to M. T.-M. and GENCAT 2015 DI 048 to D. C.-B.) and by the Torres Quevedo Program from the Spanish Ministry of Economy and Competitiveness to A. F.-V. No competing interest declared.
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Affiliation(s)
- Marc Torra-Massana
- Clínica EUGIN, Barcelona, Spain.,Faculty of Medicine, University of Barcelona, Barcelona, Spain
| | | | | | | | | | | | | | - Rafael Oliva
- Faculty of Medicine, University of Barcelona, Barcelona, Spain.,Molecular Biology of Reproduction and Development Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Fundació Clínic per a la Recerca Biomèdica, Faculty of Medicine, University of Barcelona, Barcelona, Spain
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16
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Kashir J, Mistry BV, BuSaleh L, Abu-Dawas R, Nomikos M, Ajlan A, Abu-Dawud R, AlYacoub N, AlHassan S, Lai FA, Assiri AM, Coskun S. Phospholipase C zeta profiles are indicative of optimal sperm parameters and fertilisation success in patients undergoing fertility treatment. Andrology 2020; 8:1143-1159. [PMID: 32298520 DOI: 10.1111/andr.12796] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 03/07/2020] [Accepted: 04/07/2020] [Indexed: 12/31/2022]
Abstract
BACKGROUND Oocyte activation is driven by intracellular calcium (Ca2+ ) oscillations induced by sperm-specific PLCζ, abrogation of which causes oocyte activation deficiency in humans. Clinical PLCζ investigations have been limited to severe male infertility conditions, while PLCζ levels and localisation patterns have yet to be associated with general sperm viability. MATERIALS AND METHODS PLCζ profiles were examined within a general population of males attending a fertility clinic (65 patients; aged 29-53), examining PLCζ throughout various fractions of sperm viability. Male recruitment criteria required a minimum sperm count of 5 × 106 spermatozoa/mL, while all female patients included in this study yielded at least five oocytes for treatment. Sperm count, motility and semen volume were recorded according to standard WHO reference guidelines and correlated with PLCζ profiles examined via immunoblotting and immunofluorescence. Appropriate fertility treatments were performed following routine clinical standard operating protocols, and fertilisation success determined by successful observation of second polar body extrusion. RESULTS AND DISCUSSION Four distinct PLCζ patterns were observed at the equatorial, acrosomal + equatorial regions of the sperm head, alongside a dispersed pattern, and a population of spermatozoa without any PLCζ. Acrosomal + equatorial PLCζ correlated most to sperm health, while dispersed PLCζ correlated to decreased sperm viability. Total levels of PLCζ exhibited significant correlations with sperm parameters. PLCζ variance corresponded to reduced sperm health, potentially underlying cases of male sub-fertility and increasing male age. Finally, significantly higher levels of PLCζ were exhibited by cases of fertilisation success, alongside higher proportions of Ac + Eq, and lower levels of dispersed PLCζ. CONCLUSIONS PLCζ potentially represents a biomarker of sperm health, and fertilisation capacity in general cases of patients seeking fertility treatment, and not just cases of repeated fertilisation. Further focused investigations are required with larger cohorts to examine the full clinical potential of PLCζ.
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Affiliation(s)
- Junaid Kashir
- College of Medicine, Alfaisal University, Riyadh, Kingdom of Saudi Arabia.,School of Biosciences, Cardiff University, Cardiff, UK.,Department of Comparative Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia
| | - Bhavesh V Mistry
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia
| | - Lujain BuSaleh
- College of Medicine, Alfaisal University, Riyadh, Kingdom of Saudi Arabia.,Department of Comparative Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia
| | - Reema Abu-Dawas
- College of Medicine, Alfaisal University, Riyadh, Kingdom of Saudi Arabia.,Department of Comparative Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia
| | - Michail Nomikos
- College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Ahmed Ajlan
- Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - Raed Abu-Dawud
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia
| | - Nadya AlYacoub
- Department of Comparative Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia
| | - Saad AlHassan
- Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - F Anthony Lai
- College of Medicine, QU Health, Qatar University, Doha, Qatar.,Biomedical Research Centre, Qatar University, Doha, Qatar
| | - Abdullah M Assiri
- College of Medicine, Alfaisal University, Riyadh, Kingdom of Saudi Arabia.,Department of Comparative Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia.,Biomedical Research Centre, Qatar University, Doha, Qatar.,Institute for Research and Medical Consultations, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Serdar Coskun
- Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
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17
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Kashir J. Increasing associations between defects in phospholipase C zeta and conditions of male infertility: not just ICSI failure? J Assist Reprod Genet 2020; 37:1273-1293. [PMID: 32285298 PMCID: PMC7311621 DOI: 10.1007/s10815-020-01748-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/12/2020] [Indexed: 12/12/2022] Open
Abstract
PURPOSE Oocyte activation is a fundamental event at mammalian fertilization. In mammals, this process is initiated by a series of characteristic calcium (Ca2+) oscillations, induced by a sperm-specific phospholipase C (PLC) termed PLCzeta (PLCζ). Dysfunction/reduction/deletion of PLCζ is associated with forms of male infertility where the sperm is unable to initiate Ca2+ oscillations and oocyte activation, specifically in cases of fertilization failure. This review article aims to systematically summarize recent advancements and controversies in the field to update expanding clinical associations between PLCζ and various male factor conditions. This article also discusses how such associations may potentially underlie defective embryogenesis and recurrent implantation failure following fertility treatments, alongside potential diagnostic and therapeutic PLCζ approaches, aiming to direct future research efforts to utilize such knowledge clinically. METHODS An extensive literature search was performed using literature databases (PubMed/MEDLINE/Web of Knowledge) focusing on phospholipase C zeta (PLCzeta; PLCζ), oocyte activation, and calcium oscillations, as well as specific male factor conditions. RESULTS AND DISCUSSION Defective PLCζ or PLCζ-induced Ca2+ release can be linked to multiple forms of male infertility including abnormal sperm parameters and morphology, sperm DNA fragmentation and oxidation, and abnormal embryogenesis/pregnancies. Such sperm exhibit absent/reduced levels, and abnormal localization patterns of PLCζ within the sperm head. CONCLUSIONS Defective PLCζ and abnormal patterns of Ca2+ release are increasingly suspected a significant causative factor underlying abnormalities or insufficiencies in Ca2+ oscillation-driven early embryogenic events. Such cases could potentially strongly benefit from relevant therapeutic and diagnostic applications of PLCζ, or even alternative mechanisms, following further focused research efforts.
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Affiliation(s)
- Junaid Kashir
- College of Medicine, Alfaisal University, Riyadh, Kingdom of Saudi Arabia. .,School of Biosciences, Cardiff University, Cardiff, UK. .,Department of Comparative Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia.
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18
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Shang YL, Zhu FX, Yan J, Chen L, Tang WH, Xiao S, Mo WK, Zhang ZG, He XJ, Qiao J, Cao YX, Li W. Novel DPY19L2 variants in globozoospermic patients and the overcoming this male infertility. Asian J Androl 2020; 21:183-189. [PMID: 30333325 PMCID: PMC6413555 DOI: 10.4103/aja.aja_79_18] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Globozoospermia has been reported to be a rare but severe causation of male infertility, which results from the failure of acrosome biogenesis and sperm head shaping. Variants of dpy-19-like 2 (DPY19L2) are highly related to globozoospermia, but related investigations have been mainly performed in patients from Western countries. Here, we performed a screening of DPY19L2 variants in a cohort of Chinese globozoospermic patients and found that five of nine patients carried DPY19L2 deletions and the other four patients contained novel DPY19L2 point mutations, as revealed by whole-exome sequencing. Patient 3 (P3) contained a heterozygous variant (c.2126+5G>A), P6 contained a homozygous nonsense mutation (c.1720C>T, p.Arg574*), P8 contained compound heterozygous variants (c.1182-1184delATC, p.Leu394_Ser395delinsPhe; c.368A>T, p.His123Arg), and P9 contained a heterozygous variant (c.1182-1184delATCTT, frameshift). We also reported intracytoplasmic sperm injection (ICSI) outcomes in the related patients, finding that ICSI followed by assisted oocyte activation (AOA) with calcium ionophore achieved high rates of live births. In summary, the infertility of these patients results from DPY19L2 dysfunction and can be treated by ICSI together with AOA.
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Affiliation(s)
- Yong-Liang Shang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fu-Xi Zhu
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China.,Anhui Province Key Laboratory of Reproductive Health and Genetics, Anhui Medical University, Hefei 230022, China
| | - Jie Yan
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China
| | - Liang Chen
- Medical Center of Reproductive and Genetics, Peking University First Hospital, Beijing 100034, China
| | - Wen-Hao Tang
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China
| | - Sai Xiao
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei-Ke Mo
- Digital China Health Technologies Co., Ltd., Beijing 100080, China
| | - Zhi-Guo Zhang
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China.,Anhui Province Key Laboratory of Reproductive Health and Genetics, Anhui Medical University, Hefei 230022, China.,Anhui Provincial Engineering Technology Research Center for Biopreservation and Artificial Organs, Hefei 230022, China
| | - Xiao-Jin He
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China.,Anhui Province Key Laboratory of Reproductive Health and Genetics, Anhui Medical University, Hefei 230022, China.,Anhui Provincial Engineering Technology Research Center for Biopreservation and Artificial Organs, Hefei 230022, China
| | - Jie Qiao
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China
| | - Yun-Xia Cao
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China.,Anhui Province Key Laboratory of Reproductive Health and Genetics, Anhui Medical University, Hefei 230022, China
| | - Wei Li
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
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19
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A homozygous nonsense mutation of PLCZ1 cause male infertility with oocyte activation deficiency. J Assist Reprod Genet 2020; 37:821-828. [PMID: 32146562 DOI: 10.1007/s10815-020-01719-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 02/13/2020] [Indexed: 12/13/2022] Open
Abstract
PURPOSE To identify the pathogenic PLCZ1 mutation involved in male infertility and fertilization failure. METHODS All coding regions of PLCZ1 were sequenced by Sanger sequencing. The expression and localization of PLCZ1 in sperm was determined by Western blotting and immunofluorescence. To promote the fertilization rate, the infertile man with PLCZ1 mutation was treated with intracytoplasmic sperm injection (ICSI) accompanied by assisted oocyte activation (AOA) in the following cycle. RESULT We identified a novel homozygous PLCZ1 nonsense mutation, c.588C>A (p.Cys196Ter) in an infertile man from a consanguineous family. No PLCZ1 protein was detected by Western blotting and immunofluorescence in ejaculated sperm from the patient. The treatment of ICSI + AOA avoided fertilization failure but did not result in pregnancy in the following cycle. CONCLUSION Our study confirmed the essential role of PLCZ1 in fertilization and male fertility, which indicated the potential prognostic value of testing for PLCZ1 mutations in primary infertile men with sperm-derived fertilization failure.
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20
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Saleh A, Kashir J, Thanassoulas A, Safieh-Garabedian B, Lai FA, Nomikos M. Essential Role of Sperm-Specific PLC-Zeta in Egg Activation and Male Factor Infertility: An Update. Front Cell Dev Biol 2020; 8:28. [PMID: 32064262 PMCID: PMC7000359 DOI: 10.3389/fcell.2020.00028] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 01/14/2020] [Indexed: 12/16/2022] Open
Abstract
Sperm-specific phospholipase C zeta (PLCζ) is widely considered to be the physiological stimulus responsible for generating calcium (Ca2+) oscillations that induce egg activation and early embryonic development during mammalian fertilization. In the mammalian testis, PLCζ expression is detected at spermiogenesis following elongated spermatid differentiation. Sperm-delivered PLCζ induces Ca2+ release via the inositol 1,4,5-trisphosphate (InsP3) signaling pathway. PLCζ is the smallest known mammalian PLC isoform identified to date, with the simplest domain organization. However, the distinctive biochemical properties of PLCζ compared with other PLC isoforms contribute to its unique potency in stimulating cytosolic Ca2+ oscillations within mammalian eggs. Moreover, studies describing PLCζ “knockout” mouse phenotypes confirm the supreme importance of PLCζ at egg activation and monospermic fertilization in mice. Importantly, a number of clinical reports have highlighted the crucial importance of PLCζ in human fertilization by associating PLCζ deficiencies with certain forms of male factor infertility. Herein, we give an update on recent advances that have refined our understanding of how sperm PLCζ triggers Ca2 + oscillations and egg activation in mammals, while also discussing the nature of a potential “alternative” sperm factor. We summarise PLCζ localization in mammalian sperm, and the direct links observed between defective PLCζ protein in sperm and documented cases of male infertility. Finally, we postulate how this sperm protein can be used as a potential diagnostic marker, and also as a powerful therapeutic agent for treatment of certain types of male infertility due to egg activation failure or even in more general cases of male subfertility.
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Affiliation(s)
- Alaaeldin Saleh
- Member of QU Health, College of Medicine, Qatar University, Doha, Qatar
| | - Junaid Kashir
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.,Department of Comparative Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | | | | | - F Anthony Lai
- Member of QU Health, College of Medicine, Qatar University, Doha, Qatar.,Biomedical Research Center, Qatar University, Doha, Qatar
| | - Michail Nomikos
- Member of QU Health, College of Medicine, Qatar University, Doha, Qatar
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21
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Parrington J, Arnoult C, Fissore RA. The eggstraordinary story of how life begins. Mol Reprod Dev 2018; 86:4-19. [PMID: 30411426 DOI: 10.1002/mrd.23083] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 11/06/2018] [Indexed: 12/24/2022]
Abstract
More than 15 years have elapsed since the identification of phospholipase C ζ1 (PLCζ) from a genomic search for mouse testis/sperm-specific PLCs. This molecule was proposed to represent the sperm factor responsible for the initiation of calcium (Ca2+ ) oscillations required for egg activation and embryo development in mammals. Supporting evidence for this role emerged from studies documenting its expression in all mammals and other vertebrate species, the physiological Ca2+ rises induced by injection of its messenger RNA into mammalian and nonmammalian eggs, and the lack of expression in infertile males that fail intracytoplasmic sperm injection. In the last year, genetic animal models have added support to its role as the long sought-after sperm factor. In this review, we highlight the findings that demonstrated the role of Ca2+ as the universal signal of egg activation and the experimental buildup that culminated with the identification of PLCζ as the soluble sperm factor. We also discuss the structural-functional properties that make PLCζ especially suited to evoke oscillations in eggs. Lastly, we examine unresolved aspects of the function and regulation of PLCζ and whether or not it is the only sperm factor in mammalian sperm.
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Affiliation(s)
- John Parrington
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Christophe Arnoult
- Université Grenoble Alpes, Grenoble, France.,Institut pour l'Avancée des Biosciences (IAB), INSERM 1209, CNRS UMR 5309, La Tronche, France
| | - Rafael A Fissore
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Massachusetts
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22
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Miura K, Matoba S, Ogonuki N, Namiki T, Ito J, Kashiwazaki N, Ogura A. Application of auxin-inducible degron technology to mouse oocyte activation with PLCζ. J Reprod Dev 2018; 64:319-326. [PMID: 29731504 PMCID: PMC6105737 DOI: 10.1262/jrd.2018-053] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
In mammals, spermatozoa activate oocytes by triggering a series of intracellular Ca2+ oscillations with phospholipase C zeta (PLCζ), a sperm-borne oocyte-activating factor. Because the introduction of PLCζ alone can induce oocyte activation, it might be a promising reagent for assisted reproductive technologies. To test this possibility, we injected human PLCζ (hPLCζ) mRNA into mouse oocytes at different concentrations. We observed the oocyte activation and subsequent embryonic development. Efficient oocyte activation and embryonic development to the blastocyst stage was achieved only with a limited range of mRNA concentrations (0.1 ng/μl). Higher concentrations of mRNA caused developmental arrest of most embryos, suggesting that excessive PLCζ protein might be harmful at this stage. In a second series of experiments, we aimed to regulate the PLCζ protein concentration in oocytes by applying auxin-inducible degron (AID) technology that allows rapid degradation of the target protein tagged with AID induced by auxin. Injection of the hPLCζ protein tagged with AID and enhanced green fluorescent protein (hPLCζ-AID-EGFP) demonstrated that high EGFP expression levels at the late 1-cell stage were efficiently reduced by auxin treatment, suggesting efficient hPLCζ degradation by this system. Furthermore, the defective development observed with higher concentrations of hPLCζ-AID-EGFP mRNA was rescued following auxin treatment. Full-term offspring were obtained by round spermatid injection with optimized hPLCζ-AID activation. Our results indicate that this AID technology can be applied to regulate the protein levels in mouse oocytes and that our optimized PLCζ system could be used for assisted fertilization in mammals.
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Affiliation(s)
- Kento Miura
- RIKEN BioResource Research Center, Ibaraki 305-0074, Japan
| | - Shogo Matoba
- RIKEN BioResource Research Center, Ibaraki 305-0074, Japan
| | - Narumi Ogonuki
- RIKEN BioResource Research Center, Ibaraki 305-0074, Japan
| | - Takafumi Namiki
- Laboratory of Animal Reproduction, Graduate School of Veterinary Science, Azabu University, Kanagawa 252-5201, Japan
| | - Junya Ito
- Laboratory of Animal Reproduction, Graduate School of Veterinary Science, Azabu University, Kanagawa 252-5201, Japan
| | - Naomi Kashiwazaki
- Laboratory of Animal Reproduction, Graduate School of Veterinary Science, Azabu University, Kanagawa 252-5201, Japan
| | - Atsuo Ogura
- RIKEN BioResource Research Center, Ibaraki 305-0074, Japan.,RIKEN Cluster for Pioneering Research, Saitama 351-0198, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan
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23
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Freour T, Barragan M, Torra-Massana M, Ferrer-Vaquer A, Vassena R. Is there an association between PAWP/WBP2NL sequence, expression, and distribution in sperm cells and fertilization failures in ICSI cycles? Mol Reprod Dev 2018; 85:163-170. [PMID: 29271520 DOI: 10.1002/mrd.22950] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 12/11/2017] [Indexed: 02/01/2023]
Abstract
Successful fertilization in mammals depends on the sperm's ability to initiate intracellular Ca2+ oscillations in the egg, a phenomenon that is elicited by Sperm-oocyte activating factors (SOAFs), whose quantitative and/or qualitative defect might result in fertilization failure. One such proposed factor is Post-acrosomal WW domain-binding protein (PAWP/WBP2NL), although its ability to activate human oocytes has been questioned and its implication in human fertilization failure remains unknown. Here, we sought to determine if PAWP/WBP2NL expression and distribution in sperm cells associate with low/complete fertilization failure in males participating in intracytoplasmic sperm injection (ICSI) cycles. This prospective study was conducted on eight couples referred for elective ICSI with either the woman's own (n = 4) or a donor eggs (n = 4). Eight sperm donor samples used in ICSI, which resulted in normal fertilization rates, were used as the control group. For each male patient and donor sperm, PAWP/WBP2NL sequence, protein expression, and cellular distribution were analyzed by PCR amplification-sequencing, Western blot, and immunofluorescence, respectively. PAWP/WBP2NL was present in all samples, and no significant differences were detected between patients with fertilization failure and donors in sequence variants or mean protein expression, or in the proportion of PAWP/WBP2NL-positive sperm. In conclusion, no clear association between PAWP/WBP2NL protein expression in sperm and fertilization outcome in ICSI were observed from this cohort.
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Affiliation(s)
- Thomas Freour
- Clínica Eugin, Barcelona, Spain.,Service de médecine de la reproduction, CHU de Nantes, Nantes, France.,Inserm UMR1064-ITUN, Nantes, France.,Faculté de médecine, Université de Nantes, Nantes, France
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24
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Kashir J, Nomikos M, Lai FA. Phospholipase C zeta and calcium oscillations at fertilisation: The evidence, applications, and further questions. Adv Biol Regul 2017; 67:148-162. [PMID: 29108881 DOI: 10.1016/j.jbior.2017.10.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 10/25/2017] [Accepted: 10/25/2017] [Indexed: 12/26/2022]
Abstract
Oocyte activation is a fundamental event at mammalian fertilisation, initiated by a series of characteristic calcium (Ca2+) oscillations in mammals. This characteristic pattern of Ca2+ release is induced in a species-specific manner by a sperm-specific enzyme termed phospholipase C zeta (PLCζ). Reduction or absence of functional PLCζ within sperm underlies male factor infertility in humans, due to mutational inactivation or abrogation of PLCζ protein expression. Underlying such clinical implications, a significant body of evidence has now been accumulated that has characterised the unique biochemical and biophysical properties of this enzyme, further aiding the unique clinical opportunities presented. Herein, we present and discuss evidence accrued over the past decade and a half that serves to support the identity of PLCζ as the mammalian sperm factor. Furthermore, we also discuss the potential novel avenues that have yet to be examined regarding PLCζ mechanism of action in both the oocyte, and the sperm. Finally, we discuss the advances that have been made regarding the clinical therapeutic and diagnostic applications of PLCζ in potentially treating male infertility as a result of oocyte activation deficiency (OAD), and also possibly more general cases of male subfertility.
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Affiliation(s)
- Junaid Kashir
- College of Biomedical & Life Sciences, School of Biosciences, Cardiff University, Cardiff, UK; Alfaisal University, College of Medicine, Riyadh, Saudi Arabia; King Faisal Specialist Hospital & Research Center, Department of Comparative Medicine, Riyadh, Saudi Arabia.
| | - Michail Nomikos
- College of Medicine, Member of QU Health, Qatar University, PO Box 2713, Doha, Qatar
| | - F Anthony Lai
- College of Biomedical & Life Sciences, School of Biosciences, Cardiff University, Cardiff, UK; College of Medicine, Member of QU Health, Qatar University, PO Box 2713, Doha, Qatar.
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25
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The role and mechanism of action of sperm PLC-zeta in mammalian fertilisation. Biochem J 2017; 474:3659-3673. [PMID: 29061915 DOI: 10.1042/bcj20160521] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 09/14/2017] [Accepted: 09/18/2017] [Indexed: 12/26/2022]
Abstract
At mammalian fertilisation, the fundamental stimulus that triggers oocyte (egg) activation and initiation of early embryonic development is an acute rise of the intracellular-free calcium (Ca2+) concentration inside the egg cytoplasm. This essential Ca2+ increase comprises a characteristic series of repetitive Ca2+ oscillations, starting soon after sperm-egg fusion. Over the last 15 years, accumulating scientific and clinical evidence supports the notion that the physiological stimulus that precedes the cytosolic Ca2+ oscillations is a novel, testis-specific phospholipase C (PLC) isoform, known as PLC-zeta (PLCζ). Sperm PLCζ catalyses the hydrolysis of phosphatidylinositol 4,5-bisphosphate triggering cytosolic Ca2+ oscillations through the inositol 1,4,5-trisphosphate signalling pathway. PLCζ is the smallest known mammalian PLC isoform with the most elementary domain organisation. However, relative to somatic PLCs, the PLCζ isoform possesses a unique potency in stimulating Ca2+ oscillations in eggs that is attributed to its novel biochemical characteristics. In this review, we discuss the latest developments that have begun to unravel the vital role of PLCζ at mammalian fertilisation and decipher its unique mechanism of action within the fertilising egg. We also postulate the significant potential diagnostic and therapeutic capacity of PLCζ in alleviating certain types of male infertility.
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26
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Xu YR, Yang WX. Calcium influx and sperm-evoked calcium responses during oocyte maturation and egg activation. Oncotarget 2017; 8:89375-89390. [PMID: 29179526 PMCID: PMC5687696 DOI: 10.18632/oncotarget.19679] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 06/19/2017] [Indexed: 12/18/2022] Open
Abstract
Under the guidance and regulation of hormone signaling, large majority of mammalian oocytes go through twice cell cycle arrest-resumption prior to the fertilized egg splits: oocyte maturation and egg activation. Cytosolic free calcium elevations and endoplasmic reticulum calcium store alternations are actively involved in triggering the complex machineries and events during oogenesis. Among these, calcium influx had been implicated in the replenishment of endoplasmic reticulum store during oocyte maturation and calcium oscillation during egg activation. This process also drove successful fertilization and early embryo development. Store-operated Ca2+ entry, acts as the principal force of calcium influx, is composed of STIM1 and Orai1 on the plasma membrane. Besides, transient receptor potential channels also participate in the process of calcium inwards. In this review, we summarize the recent researches on the spatial-temporal distribution of store-operated calcium entry components and transient receptor potential channels. Questions about how these channels play function for calcium influx and what impacts these channels have on oocytes are discussed. At the time of sperm-egg fusion, sperm-specific factor(s) diffuse and enable eggs to mount intracellular calcium oscillations. In this review, we also focus on the basic knowledge and the modes of action of the potential sperm factor phospholipase C zeta, as well as the downstream receptor, type 1 inositol 1,4,5-trisphosphate receptor. From the achievement in the previous several decades, it is easy to find that there are too many doubtful points in the field that need researchers take into consideration and take action in the future.
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Affiliation(s)
- Ya-Ru Xu
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Wan-Xi Yang
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou, China
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27
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Hachem A, Godwin J, Ruas M, Lee HC, Ferrer Buitrago M, Ardestani G, Bassett A, Fox S, Navarrete F, de Sutter P, Heindryckx B, Fissore R, Parrington J. PLCζ is the physiological trigger of the Ca 2+ oscillations that induce embryogenesis in mammals but conception can occur in its absence. Development 2017; 144:2914-2924. [PMID: 28694258 DOI: 10.1242/dev.150227] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 07/01/2017] [Indexed: 12/21/2022]
Abstract
Activation of the egg by the sperm is the first, vital stage of embryogenesis. The sperm protein PLCζ has been proposed as the physiological agent that triggers the Ca2+ oscillations that normally initiate embryogenesis. Consistent with this, recombinant PLCζ induces Ca2+ oscillations in eggs and debilitating mutations in the PLCZ1 gene are associated with infertility in men. However, there has been no evidence that knockout of the gene encoding PLCζ abolishes the ability of sperm to induce Ca2+ oscillations in eggs. Here, we show that sperm derived from Plcz1-/- male mice fail to trigger Ca2+ oscillations in eggs, cause polyspermy and thus demonstrate that PLCζ is the physiological trigger of these Ca2+ oscillations. Remarkably, some eggs fertilized by PLCζ-null sperm can develop, albeit at greatly reduced efficiency, and after a significant time-delay. In addition, Plcz1-/- males are subfertile but not sterile, suggesting that in the absence of PLCζ, spontaneous egg activation can eventually occur via an alternative route. This is the first demonstration that in vivo fertilization without the normal physiological trigger of egg activation can result in offspring. PLCζ-null sperm now make it possible to resolve long-standing questions in fertilization biology, and to test the efficacy and safety of procedures used to treat human infertility.
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Affiliation(s)
- Alaa Hachem
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Jonathan Godwin
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Margarida Ruas
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Hoi Chang Lee
- Department of Veterinary and Animal Sciences, University of Massachusetts, 661 North Pleasant Street, Amherst, MA 01003-9286, USA
| | - Minerva Ferrer Buitrago
- Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - Goli Ardestani
- Department of Veterinary and Animal Sciences, University of Massachusetts, 661 North Pleasant Street, Amherst, MA 01003-9286, USA
| | - Andrew Bassett
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Sebastian Fox
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Felipe Navarrete
- Department of Veterinary and Animal Sciences, University of Massachusetts, 661 North Pleasant Street, Amherst, MA 01003-9286, USA
| | - Petra de Sutter
- Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - Björn Heindryckx
- Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - Rafael Fissore
- Department of Veterinary and Animal Sciences, University of Massachusetts, 661 North Pleasant Street, Amherst, MA 01003-9286, USA
| | - John Parrington
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
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28
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Gat I, Orvieto R. "This is where it all started" - the pivotal role of PLCζ within the sophisticated process of mammalian reproduction: a systemic review. Basic Clin Androl 2017; 27:9. [PMID: 28533904 PMCID: PMC5438850 DOI: 10.1186/s12610-017-0054-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 03/26/2017] [Indexed: 12/14/2022] Open
Abstract
Mammalian reproduction is one of the most complex and fascinating biological phenomenon, which aims to transfer maternal and paternal genetic material to the next generation. At the end of oogenesis and spermatogenesis, both haploid gametes contain a single set of chromosomes ready to form the zygote, the first cell of the newly developing individual. The mature oocyte and spermatozoa remain in a quiescent state, during which the oocyte is characterized by nuclear and cytoplasmic arrest, while the spermatozoa necessitates further maturation within the epididymis and female reproductive track prior to egg fertilization. Either in vivo or in vitro, the sperm initiates a series of irreversible biochemical and physiological modifications in the oocyte. The earliest detected signal after fertilization is cytosolic Ca2+ oscillations, a prerequisite step for embryo development. These oscillations trigger the release of the oocyte from the second meiosis arrest towards embryogenesis, also known as “oocyte activation”. Phospholipase C zeta (PLCζ) is a unique sperm-soluble protein responsible for triggering the InsP3/Ca2+ pathway within the oocyte, leading to Ca2+ oscillations and consequently to embryo development. The specific structure of PLCζ (compared to other PLCs) enables its specialized activity via the preserved X and Y catalytic domains, as well as distinct features such as rapid onset, high sensitivity to Ca2+ and cession of oscillations upon zygote formation. The emerging discoveries of PLCζ have stimulated studies focusing on the possible clinical applications of this protein in male infertility evaluation and management during IVF/ICSI. Fertilization failure is attributed to lack of oocyte second meiosis resumption, suggesting that ICSI failure may be related to impaired PLCζ activity. Microinjection of recombinant human PLCζ to human oocytes after ICSI fertilization failure may trigger Ca2+ oscillations and achieve successful fertilization, offering new hope for couples traditionally referred to sperm donation. However, more studies are still required prior to the routine implementation of this approach in the clinic. Directions for future studies are discussed.
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Affiliation(s)
- Itai Gat
- IVF Unit, Department of Obstetrics and Gynecology, Sheba Medical Center, Tel Hashomer, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Pinchas Borenstein Talpiot Medical Leadership Program, Sheba Medical Center, Tel Hashomer, Israel
| | - Raoul Orvieto
- IVF Unit, Department of Obstetrics and Gynecology, Sheba Medical Center, Tel Hashomer, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,The Tarnesby-Tarnowski Chair for Family Planning and Fertility Regulation, Sackler Faculty of Medicine, Tel Aviv, Israel
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Yeste M, Jones C, Amdani SN, Coward K. Oocyte Activation and Fertilisation: Crucial Contributors from the Sperm and Oocyte. Results Probl Cell Differ 2017; 59:213-239. [PMID: 28247051 DOI: 10.1007/978-3-319-44820-6_8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
This chapter intends to summarise the importance of sperm- and oocyte-derived factors in the processes of sperm-oocyte binding and oocyte activation. First, we describe the initial interaction between sperm and the zona pellucida, with particular regard to acrosome exocytosis. We then describe how sperm and oocyte membranes fuse, with special reference to the discovery of the sperm protein IZUMO1 and its interaction with the oocyte membrane receptor JUNO. We then focus specifically upon oocyte activation, the fundamental process by which the oocyte is alleviated from metaphase II arrest by a sperm-soluble factor. The identity of this sperm factor has been the source of much debate recently, although mounting evidence, from several different laboratories, provides strong support for phospholipase C ζ (PLCζ), a sperm-specific phospholipase. Herein, we discuss the evidence in support of PLCζ and evaluate the potential role of other candidate proteins, such as post-acrosomal WW-binding domain protein (PAWP/WBP2NL). Since the cascade of downstream events triggered by the sperm-borne oocyte activation factor heavily relies upon specialised cellular machinery within the oocyte, we also discuss the critical role of oocyte-borne factors, such as the inositol trisphosphate receptor (IP3R), protein kinase C (PKC), store-operated calcium entry (SOCE) and calcium/calmodulin-dependent protein kinase II (CaMKII), during the process of oocyte activation. In order to place the implications of these various factors and processes into a clinical context, we proceed to describe their potential association with oocyte activation failure and discuss how clinical techniques such as the in vitro maturation of oocytes may affect oocyte activation ability. Finally, we contemplate the role of artificial oocyte activating agents in the clinical rescue of oocyte activation deficiency and discuss options for more endogenous alternatives.
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Affiliation(s)
- Marc Yeste
- Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, C/ Maria Aurèlia Campany, 69, Campus Montilivi, E-17071, Girona, Spain. .,Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, UK.
| | - Celine Jones
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, UK
| | - Siti Nornadhirah Amdani
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, UK
| | - Kevin Coward
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, UK
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Kashir J, Buntwal L, Nomikos M, Calver BL, Stamatiadis P, Ashley P, Vassilakopoulou V, Sanders D, Knaggs P, Livaniou E, Bunkheila A, Swann K, Lai FA. Antigen unmasking enhances visualization efficacy of the oocyte activation factor, phospholipase C zeta, in mammalian sperm. Mol Hum Reprod 2016; 23:54-67. [PMID: 27932551 DOI: 10.1093/molehr/gaw073] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 09/23/2016] [Accepted: 11/21/2016] [Indexed: 12/14/2022] Open
Abstract
STUDY QUESTION Is it possible to improve clinical visualization of phospholipase C zeta (PLCζ) as a diagnostic marker of sperm oocyte activation capacity and male fertility? SUMMARY ANSWER Poor PLCζ visualization efficacy using current protocols may be due to steric or conformational occlusion of native PLCζ, hindering antibody access, and is significantly enhanced using antigen unmasking/retrieval (AUM) protocols. WHAT IS KNOWN ALREADY Mammalian oocyte activation is mediated via a series of intracellular calcium (Ca2+) oscillations induced by sperm-specific PLCζ. PLCζ represents not only a potential clinical therapeutic in cases of oocyte activation deficiency but also a diagnostic marker of sperm fertility. However, there are significant concerns surrounding PLCζ antibody specificity and detection protocols. STUDY DESIGN, SIZE DURATION Two PLCζ polyclonal antibodies, with confirmed PLCζ specificity, were employed in mouse, porcine and human sperm. Experiments evaluated PLCζ visualization efficacy, and whether AUM improved this. Antibodies against two sperm-specific proteins [post-acrosomal WW-binding protein (PAWP) and acrosin] were used as controls. PARTICIPANTS/MATERIALS, SETTING, METHODS Aldehyde- and methanol-fixed sperm were subject to immunofluorescence analysis following HCl exposure (pH = 0.1-0.5), acid Tyrode's solution exposure (pH = 2.5) or heating in 10 mM sodium citrate solution (pH = 6.0). Fluorescence intensity of at least 300 cells was recorded for each treatment, with three independent repeats. MAIN RESULTS AND THE ROLE OF CHANCE Despite high specificity for native PLCζ following immunoblotting using epitope-specific polyclonal PLCζ antibodies in mouse, porcine and human sperm, immunofluorescent visualization efficacy was poor. In contrast, sperm markers PAWP and acrosin exhibited relatively impressive results. All methods of AUM on aldehyde-fixed sperm enhanced visualization efficacy for PLCζ compared to visualization efficacy before AUM (P < 0.05 for all AUM interventions), but exerted no significant change upon PAWP or acrosin immunofluorescence following AUM. All methods of AUM enhanced PLCζ visualization efficacy in mouse and human methanol-fixed sperm compared to without AUM (P < 0.05 for all AUM interventions), while no significant change was observed in methanol-fixed porcine sperm before and after. In the absence of aldehyde-induced cross-linkages, such results suggest that poor PLCζ visualization efficacy may be due to steric or conformational occlusion of native PLCζ, hindering antibody access. Importantly, examination of sperm from individual donors revealed that AUM differentially affects observable PLCζ fluorescence, and the proportion of sperm exhibiting detectable PLCζ fluorescence in sperm from different males. LIMITATIONS, REASONS FOR CAUTION Direct correlation of fertility outcomes with the level of PLCζ in the sperm samples studied was not available. Such analyses would be required in future to determine whether the improved methodology for PLCζ visualization we propose would indeed reflect fertility status. WIDER IMPLICATIONS OF THE FINDINGS We propose that AUM alters conformational interactions to enhance PLCζ epitope availability and visualization efficacy, supporting prospective application of AUM to reduce misinterpretation in clinical diagnosis of PLCζ-linked male infertility. Our current results suggest that it is perhaps prudent that previous studies investigating links between PLCζ and fertility parameters are re-examined in the context of AUM, and may pave the way for future work to answer significant questions such as how PLCζ appears to be kept in an inactive form in the sperm. LARGE SCALE DATA Not applicable. STUDY FUNDING/COMPETING INTERESTS J.K. is supported by a Health Fellowship award from the National Institute for Social Care and Health Research (NISCHR). M.N. is supported by a Marie Curie Intra-European Research Fellowship award. This work was also partly funded by a research grant from Cook Medical Technologies LLC. There are no competing financial interests to declare.
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Affiliation(s)
- Junaid Kashir
- College of Biomedical and Life Sciences, Schools of Bioscience & Medicine, Cardiff University, Cardiff, UK .,Alfaisal University, College of Medicine, Riyadh, Saudi Arabia.,King Faisal Specialist Hospital & Research Center, Department of Comparative Medicine, Riyadh, Saudi Arabia
| | - Luke Buntwal
- College of Biomedical and Life Sciences, Schools of Bioscience & Medicine, Cardiff University, Cardiff, UK
| | - Michail Nomikos
- Qatar University, College of Medicine, PO BOX 2713, Doha, Qatar.,School of Medicine, Cardiff University, UK
| | - Brian L Calver
- College of Biomedical and Life Sciences, Schools of Bioscience & Medicine, Cardiff University, Cardiff, UK
| | - Panagiotis Stamatiadis
- College of Biomedical and Life Sciences, Schools of Bioscience & Medicine, Cardiff University, Cardiff, UK
| | - Peter Ashley
- Wales Fertility Institute, University Hospital Wales, Cardiff, UK
| | | | - David Sanders
- Wales Fertility Institute, University Hospital Wales, Cardiff, UK
| | - Paul Knaggs
- Wales Fertility Institute, University Hospital Wales, Cardiff, UK
| | - Evangelia Livaniou
- National Center for Scientific Research 'Demokritos', 15310 Aghia Paraskevi, Greece
| | - Adnan Bunkheila
- Wales Fertility Institute, University Hospital Wales, Cardiff, UK
| | - Karl Swann
- College of Biomedical and Life Sciences, Schools of Bioscience & Medicine, Cardiff University, Cardiff, UK
| | - F Anthony Lai
- College of Biomedical and Life Sciences, Schools of Bioscience & Medicine, Cardiff University, Cardiff, UK
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Abstract
A series of intracellular oscillations in the free cytosolic Ca(2+) concentration is responsible for activating mammalian eggs at fertilization, thus initiating embryo development. It has been proposed that the sperm causes these Ca(2+) oscillations after membrane fusion by delivering a soluble protein into the egg cytoplasm. We previously identified sperm-specific phospholipase C (PLC)-ζ as a protein that can trigger the same pattern of Ca(2+) oscillations in eggs seen at fertilization. PLCζ appears to be the elusive sperm factor mediating egg activation in mammals. It has potential therapeutic use in infertility treatments to improve the rate of egg activation and early embryo development after intra-cytoplasmic sperm injection. A stable form of recombinant human PLCζ could be a prototype for use in such in vitro fertilization (IVF) treatments. We do not yet understand exactly how PLCζ causes inositol 1,4,5-trisphosphate (InsP3) production in eggs. Sperm PLCζ is distinct among mammalian PI-specific PLCs in that it is far more potent in triggering Ca(2+) oscillations in eggs than other PLCs, but it lacks a PH domain that would otherwise be considered essential for binding to the phosphatidylinositol 4,5-bisphosphate (PIP2) substrate. PLCζ is also unusual in that it does not appear to interact with or hydrolyse plasma membrane PIP2. We consider how other regions of PLCζ may mediate its binding to PIP2 in eggs and how interaction of PLCζ with egg-specific factors could enable the hydrolysis of internal sources of PIP2.
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Janghorban-Laricheh E, Ghazavi-Khorasgani N, Tavalaee M, Zohrabi D, Abbasi H, Nasr-Esfahani MH. An association between sperm PLCζ levels and varicocele? J Assist Reprod Genet 2016; 33:1649-1655. [PMID: 27612872 DOI: 10.1007/s10815-016-0802-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/19/2016] [Indexed: 10/21/2022] Open
Abstract
PURPOSE We aimed to compare the expression of phospholipase C ζ (PLCζ), as one of the main sperm factors involved in oocyte activation, at both RNA and protein levels in fertile men and those with varicocele. METHODS This study included 35 individuals with male factor infertility presenting primary infertility with grade II and III unilateral varicocele and 20 fertile men without varicocele. Semen parameters were assessed according to WHO 2010. Sperm DNA fragmentation, relative expression of PLCζ at messenger RNA, and protein levels were evaluated by sperm chromatin structure assay (SCSA), real-time PCR, and Western blot analysis, respectively. RESULTS The results of this study reveal that the mean relative expression of PLCζ was significantly lower in individuals with varicocele compared to fertile men at both transcription and translation levels. In addition, the percentage of DNA fragmentation was significantly higher in infertile men with varicocele compared to fertile men. CONCLUSIONS The findings of the present study illustrate that one of the etiologies of reduced fertility associated with varicocele is the low expression of PLCζ. This effect could subsequently reduce the sperm ability to induce oocyte activation. Therefore, these results hold promise to modify our understanding of reproductive physiology of varicocele state.
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Affiliation(s)
- Elham Janghorban-Laricheh
- Department of Reproductive Biotechnology, Reproductive Biomedicine Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran.,Department of Biology, Nourdanesh Institute of Higher Education, Meymeh, Isfahan, Iran
| | - Nasim Ghazavi-Khorasgani
- Department of Reproductive Biotechnology, Reproductive Biomedicine Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran.,Department of Biology, Nourdanesh Institute of Higher Education, Meymeh, Isfahan, Iran
| | - Marziyeh Tavalaee
- Department of Reproductive Biotechnology, Reproductive Biomedicine Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Dina Zohrabi
- Department of Biology, Nourdanesh Institute of Higher Education, Meymeh, Isfahan, Iran
| | | | - Mohammad H Nasr-Esfahani
- Department of Reproductive Biotechnology, Reproductive Biomedicine Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran. .,Isfahan Fertility and Infertility Center, Isfahan, Iran.
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Yeste M, Jones C, Amdani SN, Yelumalai S, Mounce G, da Silva SJM, Child T, Coward K. Does advancing male age influence the expression levels and localisation patterns of phospholipase C zeta (PLCζ) in human sperm? Sci Rep 2016; 6:27543. [PMID: 27270687 PMCID: PMC4897631 DOI: 10.1038/srep27543] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 05/17/2016] [Indexed: 12/02/2022] Open
Abstract
Socio-economic factors have led to an increasing trend for couples to delay parenthood. However, advancing age exerts detrimental effects upon gametes which can have serious consequences upon embryo viability. While such effects are well documented for the oocyte, relatively little is known with regard to the sperm. One fundamental role of sperm is to activate the oocyte at fertilisation, a process initiated by phospholipase C zeta (PLCζ), a sperm-specific protein. While PLCζ deficiency can lead to oocyte activation deficiency and infertility, it is currently unknown whether the expression or function of PLCζ is compromised by advancing male age. Here, we evaluate sperm motility and the proportion of sperm expressing PLCζ in 71 males (22–54 years; 44 fertile controls and 27 infertile patients), along with total levels and localisation patterns of PLCζ within the sperm head. Three different statistical approaches were deployed with male age considered both as a categorical and a continuous factor. While progressive motility was negatively correlated with male age, all three statistical models concurred that no PLCζ–related parameter was associated with male age, suggesting that advancing male age is unlikely to cause problems in terms of the sperm’s fundamental ability to activate an oocyte.
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Affiliation(s)
- Marc Yeste
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, United Kingdom
| | - Celine Jones
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, United Kingdom
| | - Siti Nornadhirah Amdani
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, United Kingdom.,PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong, Brunei Darussalam
| | - Suseela Yelumalai
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, United Kingdom
| | - Ginny Mounce
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, United Kingdom
| | - Sarah J Martins da Silva
- Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, Dundee, DD1 9SY, UK.,Assisted Conception Unit, NHS Tayside, Ninewells Hospital, Dundee, DD1 9SY, UK
| | - Tim Child
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, United Kingdom.,Oxford Fertility, Institute of Reproductive Sciences, Oxford Business Park North, Alec Issigonis Way, Oxford, OX4 2HW
| | - Kevin Coward
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, United Kingdom
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35
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Sanders JR, Swann K. Molecular triggers of egg activation at fertilization in mammals. Reproduction 2016; 152:R41-50. [PMID: 27165049 DOI: 10.1530/rep-16-0123] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 05/09/2016] [Indexed: 01/15/2023]
Abstract
In mammals, the sperm activates the development of the egg by triggering a series of oscillations in the cytosolic-free Ca(2+) concentration (Ca(2+) i). The sperm triggers these cytosolic Ca(2+i) oscillations after sperm-egg membrane fusion, as well as after intracytoplasmic sperm injection (ICSI). These Ca(2+) i oscillations are triggered by a protein located inside the sperm. The identity of the sperm protein has been debated over many years, but all the repeatable data now suggest that it is phospholipase Czeta (PLCζ). The main downstream target of Ca(2+) i oscillations is calmodulin-dependent protein kinase II (CAMKII (CAMK2A)), which phosphorylates EMI2 and WEE1B to inactivate the M-phase promoting factor protein kinase activity (MPF) and this ultimately triggers meiotic resumption. A later decline in the activity of mitogen-activated protein kinase (MAPK) then leads to the completion of activation which is marked by the formation of pronuclei and entry into interphase of the first cell cycle. The early cytosolic Ca(2+) increases also trigger exocytosis via a mechanism that does not involve CAMKII. We discuss some recent developments in our understanding of these triggers for egg activation within the framework of cytosolic Ca(2+) signaling.
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Affiliation(s)
| | - Karl Swann
- School of BiosciencesCardiff University, Cardiff, UK
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36
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Ferrer-Vaquer A, Barragan M, Freour T, Vernaeve V, Vassena R. PLCζ sequence, protein levels, and distribution in human sperm do not correlate with semen characteristics and fertilization rates after ICSI. J Assist Reprod Genet 2016; 33:747-56. [PMID: 27138933 DOI: 10.1007/s10815-016-0718-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 04/18/2016] [Indexed: 12/13/2022] Open
Abstract
PURPOSE Sperm-borne PLCζ protein induces Ca(2+) oscillations in the oocyte and is believed to play a major role during oocyte activation. However, its implication in fertilization failure following ICSI is still debated. We analyzed PLCζ gene sequence, protein expression level, and localization in both patients with previous failed fertilization by ICSI and sperm donors with proven fertility in order to assess the association of PLCζ with both sperm characteristics and ability to fertilize. METHODS Semen from 15 patients and 13 sperm donors with proven fertility was included in the study. Analysis of the PLCζ gene sequence, protein expression through Western blot, and protein localization by immunofluorescence were performed. RESULTS Two patients with total fertilization failure presented mutations in heterozygosis in the PLCζ gene. Comparison with donor sample sequences displayed comparable SNP allele frequency. Distribution pattern of PLCζ did not vary significantly between donor and patient samples. Levels of PLCζ protein in sperm cells showed an interindividual variability both in patient and donor samples. Several SNPs previously reported in infertile patients were also present in fertile men. CONCLUSION Failed fertilization occurs even when levels and distribution of PLCζ protein are within normal range. PLCζ seems to be a necessary but not sufficient factor in determining the molecular pathway involved in oocyte activation.
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Affiliation(s)
| | | | - Thomas Freour
- Clínica EUGIN, Travessera de les Corts 322, 08029, Barcelona, Spain.,Service de médecine et biologie de la reproduction, CHU de Nantes, Nantes, France.,INSERM UMR 1064, Nantes, France
| | - Valérie Vernaeve
- Clínica EUGIN, Travessera de les Corts 322, 08029, Barcelona, Spain
| | - Rita Vassena
- Clínica EUGIN, Travessera de les Corts 322, 08029, Barcelona, Spain.
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Javadian-Elyaderani S, Ghaedi K, Tavalaee M, Rabiee F, Deemeh MR, Nasr-Esfahani MH. Diagnosis of genetic defects through parallel assessment of PLCζ and CAPZA3 in infertile men with history of failed oocyte activation. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2016; 19:281-9. [PMID: 27114798 PMCID: PMC4834118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Accepted: 12/24/2015] [Indexed: 11/12/2022]
Abstract
OBJECTIVES Phospholipase C ζ (PLCζ) is considered as a nominee for sperm associated oocyte activating factors and is located back-to-back with CAPZA3, an actin-capping protein controlling actin polymerization during spermiogenesis. They contain a common bidirectional promoter. The objective of this study was to identify individuals with parallel low expression of PLCζ and CAPZA3 mRNA, in hope of detecting genetic defects in this bidirectional promoter. MATERIALS AND METHODS Semen samples were collected from 24 fertile and 59 infertile individuals with total failed, low and high fertilization rate post intra-cytoplasmic sperm injection (ICSI), as well as globozoospermic individuals. Expression of PLCζ and CAPZA3 were assessed by Real time PCR. In addition, PLCζ was assessed by Western blot. RESULTS Significant correlations between PLCζ with CAPZA3 and also between these two genes with fertilization were observed. Individuals with low fertilization presented significantly lower expression of these two genes. Low expression of PLCζ was also verified by Western analysis. Sequence analysis of bidirectional promoter of these two genes in an individual with parallel low expression of both PLCζ and CAPZA3, revealed a mutation within the CAPZA3 predicted promoter, known as human regulatory factor X4 which is a testis-specific dimeric DNA-binding protein. In the opposite stand, in the same location, the mutation appears to be outside but in the vicinity of PLCζ, in a binding region predicate by Genomatix. CONCLUSION Parallel assessment of CAPZA3 with PLCζ at mRNA level in individuals with inability to induce oocyte activation may help researcher to identify genetic defects associated with failed fertilization.
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Affiliation(s)
- Soudabeh Javadian-Elyaderani
- Department of Reproductive Biotechnology, Reproductive Biomedicine Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Kamran Ghaedi
- Department of Molecular Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
- Biology Department, School of Sciences, University of Isfahan, Isfahan, Iran
| | - Marziyeh Tavalaee
- Department of Reproductive Biotechnology, Reproductive Biomedicine Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Farzaneh Rabiee
- Department of Molecular Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Mohammad Reza Deemeh
- Department of Reproductive Biotechnology, Reproductive Biomedicine Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Mohammad Hossein Nasr-Esfahani
- Department of Reproductive Biotechnology, Reproductive Biomedicine Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
- Department of Molecular Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
- Isfahan Fertility and Infertility Center, Isfahan, Iran
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Abstract
The most fundamental unresolved issue of fertilization is to define how the sperm activates the egg to begin embryo development. Egg activation at fertilization in all species thus far examined is caused by some form of transient increase in the cytoplasmic free Ca2+ concentration. What has not been clear, however, is precisely how the sperm triggers the large changes in Ca2+ observed within the egg cytoplasm. Here, we review the studies indicating that the fertilizing sperm stimulates a cytosolic Ca2+ increase in the egg specifically by delivering a soluble factor that diffuses into the cytosolic space of the egg upon gamete membrane fusion. Evidence is primarily considered in species of eggs where the sperm has been shown to elicit a cytosolic Ca2+ increase by initiating Ca2+ release from intracellular Ca2+ stores. We suggest that our best understanding of these signaling events is in mammals, where the sperm triggers a prolonged series of intracellular Ca2+ oscillations. The strongest empirical studies to date suggest that mammalian sperm-triggered Ca2+ oscillations are caused by the introduction of a sperm-specific protein, called phospholipase C-zeta (PLCζ) that generates inositol trisphosphate within the egg. We will discuss the role and mechanism of action of PLCζ in detail at a molecular and cellular level. We will also consider some of the evidence that a soluble sperm protein might be involved in egg activation in nonmammalian species.
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Affiliation(s)
- Karl Swann
- College of Biomedical and Life Sciences, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - F. Anthony Lai
- College of Biomedical and Life Sciences, School of Medicine, Cardiff University, Cardiff, United Kingdom
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39
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Amdani SN, Yeste M, Jones C, Coward K. Phospholipase C zeta (PLCζ) and male infertility: Clinical update and topical developments. Adv Biol Regul 2015; 61:58-67. [PMID: 26700242 DOI: 10.1016/j.jbior.2015.11.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 11/26/2015] [Accepted: 11/26/2015] [Indexed: 01/09/2023]
Abstract
The development of a mammalian embryo is initiated by a sequence of molecular events collectively referred to as 'oocyte activation' and regulated by the release of intracellular calcium in the ooplasm. Over the last decade, phospholipase C zeta (PLCζ), a sperm protein introduced into the oocyte upon gamete fusion, has gained almost universal acceptance as the protein factor responsible for initiating oocyte activation. A large body of consistent and reproducible evidence, from both biochemical and clinical settings, confers support for the role of PLCζ in this fundamental biological context, which has significant ramifications for the management of human male infertility. Oocyte activation deficiency (OAD) and total fertilisation failure (TFF) are known causes of infertility and have both been linked to abnormalities in the structure, expression, and localisation pattern of PLCζ in human sperm. Assisted oocyte activators (AOAs) represent the only therapeutic option available for OAD at present, although these agents have been the source of much debate recently, particularly with regard to their potential epigenetic effects upon the embryo. Consequently, there is much interest in the deployment of sensitive PLCζ assays as prognostic/diagnostic tests and human recombinant PLCζ protein as an alternative form of therapy. Although PLCζ deficiency has been directly linked to a cohort of infertile cases, we have yet to identify the specific causal mechanisms involved. While two genetic mutations have been identified which link defective PLCζ protein to an infertile phenotype, both were observed in the same patient, and have yet to be described in other patients. Consequently, some researchers are investigating the possibility that genetic variations in the form of single nucleotide polymorphisms (SNPs) could provide some explanation, especially since >6000 SNPs have been identified in the PLCζ gene. As yet, however, there is no consistent data to suggest that any of these SNPs influence the functional ability of PLCζ. Other laboratories appear to be focussing upon the PLCζ promoter, which is bi-directional and shared with the actin filament capping muscle Z-line alpha 3 gene (CAPZA3), or seeking to identify interacting proteins within the ooplasm. The aim of this review is to provide a synopsis of recent progress in the application of PLCζ in diagnostic and therapeutic medicine, to discuss our current understanding of how the functional ability of PLCζ might be controlled, and thus how PLCζ deficiency might arise, and finally, to consider the potential implications of alternative sperm protein candidates, such as post-acrosomal WW-domain binding protein (PAWP), which has caused much debate and confusion in the field over the last few years.
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Affiliation(s)
- Siti Nornadhirah Amdani
- Nuffield Department of Obstetrics & Gynaecology, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK; PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, Jalan Tunku Link, Gadong, Brunei Darussalam
| | - Marc Yeste
- Nuffield Department of Obstetrics & Gynaecology, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
| | - Celine Jones
- Nuffield Department of Obstetrics & Gynaecology, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
| | - Kevin Coward
- Nuffield Department of Obstetrics & Gynaecology, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK.
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Yeste M, Jones C, Amdani SN, Patel S, Coward K. Oocyte activation deficiency: a role for an oocyte contribution? Hum Reprod Update 2015; 22:23-47. [DOI: 10.1093/humupd/dmv040] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 08/13/2015] [Indexed: 12/11/2022] Open
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Amdani SN, Yeste M, Jones C, Coward K. Sperm Factors and Oocyte Activation: Current Controversies and Considerations1. Biol Reprod 2015; 93:50. [DOI: 10.1095/biolreprod.115.130609] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 06/30/2015] [Indexed: 11/01/2022] Open
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Sanusi R, Yu Y, Nomikos M, Lai FA, Swann K. Rescue of failed oocyte activation after ICSI in a mouse model of male factor infertility by recombinant phospholipase Cζ. Mol Hum Reprod 2015; 21:783-91. [PMID: 26187950 PMCID: PMC4586348 DOI: 10.1093/molehr/gav042] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 07/13/2015] [Indexed: 12/17/2022] Open
Abstract
Artificial oocyte activation to overcome failed fertilization after intracytoplasmic sperm injection (ICSI) in human oocytes typically employs Ca(2+) ionophores to produce a single cytosolic Ca(2+) increase. In contrast, recombinant phospholipase Czeta (PLCζ) causes Ca(2+) oscillations indistinguishable from those occurring during fertilization, but remains untested for its efficacy in a scenario of ICSI fertilization failure. Here, we compare PLCζ with other activation stimuli in a mouse model of failed oocyte activation after ICSI, in which heat-treated sperm are injected into mouse oocytes. We show that increasing periods of 56 °C exposure of sperm produces a progressive loss of Ca(2+) oscillations after ICSI. The decrease in Ca(2+) oscillations produces a reduction in oocyte activation and embryo development to the blastocyst stage. We treated such oocytes that failed to activate after ICSI either with Ca(2+) ionophore, or with Sr(2+) media which causes Ca(2+) oscillations, or we injected them with recombinant human PLCζ. All these treatments rescued oocyte activation, although Sr(2+) and PLCζ gave the highest rates of development to blastocyst. When recombinant PLCζ was given to oocytes previously injected with control sperm, they developed normally to the blastocyst stage at rates similar to that after control ICSI. The data suggest that recombinant human PLCζ protein is an efficient means of rescuing oocyte activation after ICSI failure and that it can be effectively used even if the sperm already contains endogenous Ca(2+) releasing activity.
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Affiliation(s)
- Randa Sanusi
- Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK
| | - Yuansong Yu
- Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK Present address: TopChoice Medical, TopChoice Building, 327 Tianmushan Road, Hangzhou City, Zhejiang Province, China
| | - Michail Nomikos
- Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK
| | - F Anthony Lai
- Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK
| | - Karl Swann
- Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK
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Schrimpf R, Dierks C, Martinsson G, Sieme H, Distl O. Genome-wide association study identifies phospholipase C zeta 1 (PLCz1) as a stallion fertility locus in Hanoverian warmblood horses. PLoS One 2014; 9:e109675. [PMID: 25354211 PMCID: PMC4212906 DOI: 10.1371/journal.pone.0109675] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 09/02/2014] [Indexed: 12/13/2022] Open
Abstract
A consistently high level of stallion fertility plays an economically important role in modern horse breeding. We performed a genome-wide association study for estimated breeding values of the paternal component of the pregnancy rate per estrus cycle (EBV-PAT) in Hanoverian stallions. A total of 228 Hanoverian stallions were genotyped using the Equine SNP50 Beadchip. The most significant association was found on horse chromosome 6 for a single nucleotide polymorphism (SNP) within phospholipase C zeta 1 (PLCz1). In the close neighbourhood to PLCz1 is located CAPZA3 (capping protein (actin filament) muscle Z-line, alpha 3). The gene PLCz1 encodes a protein essential for spermatogenesis and oocyte activation through sperm induced Ca2+-oscillation during fertilization. We derived equine gene models for PLCz1 and CAPZA3 based on cDNA and genomic DNA sequences. The equine PLCz1 had four different transcripts of which two contained a premature termination codon. Sequencing all exons and their flanking sequences using genomic DNA samples from 19 Hanoverian stallions revealed 47 polymorphisms within PLCz1 and one SNP within CAPZA3. Validation of these 48 polymorphisms in 237 Hanoverian stallions identified three intronic SNPs within PLCz1 as significantly associated with EBV-PAT. Bioinformatic analysis suggested regulatory effects for these SNPs via transcription factor binding sites or microRNAs. In conclusion, non-coding polymorphisms within PLCz1 were identified as conferring stallion fertility and PLCz1 as candidate locus for male fertility in Hanoverian warmblood. CAPZA3 could be eliminated as candidate gene for fertility in Hanoverian stallions.
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Affiliation(s)
- Rahel Schrimpf
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Claudia Dierks
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, Hannover, Germany
| | | | - Harald Sieme
- Clinic for Horses, Unit for Reproduction Medicine, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Ottmar Distl
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, Hannover, Germany
- * E-mail:
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Nomikos M, Theodoridou M, Elgmati K, Parthimos D, Calver BL, Buntwal L, Nounesis G, Swann K, Lai FA. Human PLCζ exhibits superior fertilization potency over mouse PLCζ in triggering the Ca(2+) oscillations required for mammalian oocyte activation. Mol Hum Reprod 2014; 20:489-98. [PMID: 24478462 DOI: 10.1093/molehr/gau011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A sperm-specific phospholipase C-zeta (PLCζ) is believed to play an essential role in oocyte activation during mammalian fertilization. Sperm PLCζ has been shown to trigger a prolonged series of repetitive Ca(2+) transients or oscillations in oocytes that precede activation. This remarkable intracellular Ca(2+) signalling phenomenon is a distinctive characteristic observed during in vitro fertilization by sperm. Previous studies have notably observed an apparent differential ability of PLCζ from disparate mammalian species to trigger Ca(2+) oscillations in mouse oocytes. However, the molecular basis and confirmation of the apparent PLCζ species difference in activity remains to be provided. In the present study, we provide direct evidence for the superior effectiveness of human PLCζ relative to mouse PLCζ in generating Ca(2+) oscillations in mouse oocytes. In addition, we have designed and constructed a series of human/mouse PLCζ chimeras to enable study of the potential role of discrete PLCζ domains in conferring the enhanced Ca(2+) signalling potency of human PLCζ. Functional analysis of these human/mouse PLCζ domain chimeras suggests a novel role of the EF-hand domain in the species-specific differences in PLCζ activity. Our empirical observations are compatible with a basic mathematical model for the Ca(2+) dependence of generating cytoplasmic Ca(2+) oscillations in mammalian oocytes by sperm PLCζ.
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Affiliation(s)
- Michail Nomikos
- Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK
| | - Maria Theodoridou
- Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK National Center for Scientific Research 'Demokritos', Aghia Paraskevi 15310, Greece
| | - Khalil Elgmati
- Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK
| | | | - Brian L Calver
- Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK
| | - Luke Buntwal
- Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK
| | - George Nounesis
- National Center for Scientific Research 'Demokritos', Aghia Paraskevi 15310, Greece
| | - Karl Swann
- Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK
| | - F Anthony Lai
- Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK
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Theodoridou M, Nomikos M, Parthimos D, Gonzalez-Garcia JR, Elgmati K, Calver BL, Sideratou Z, Nounesis G, Swann K, Lai FA. Chimeras of sperm PLCζ reveal disparate protein domain functions in the generation of intracellular Ca2+ oscillations in mammalian eggs at fertilization. Mol Hum Reprod 2013; 19:852-64. [PMID: 24152875 DOI: 10.1093/molehr/gat070] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Phospholipase C-zeta (PLCζ) is a sperm-specific protein believed to cause Ca(2+) oscillations and egg activation during mammalian fertilization. PLCζ is very similar to the somatic PLCδ1 isoform but is far more potent in mobilizing Ca(2+) in eggs. To investigate how discrete protein domains contribute to Ca(2+) release, we assessed the function of a series of PLCζ/PLCδ1 chimeras. We examined their ability to cause Ca(2+) oscillations in mouse eggs, enzymatic properties using in vitro phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis and their binding to PIP2 and PI(3)P with a liposome interaction assay. Most chimeras hydrolyzed PIP2 with no major differences in Ca(2+) sensitivity and enzyme kinetics. Insertion of a PH domain or replacement of the PLCζ EF hands domain had no deleterious effect on Ca(2+) oscillations. In contrast, replacement of either XY-linker or C2 domain of PLCζ completely abolished Ca(2+) releasing activity. Notably, chimeras containing the PLCζ XY-linker bound to PIP2-containing liposomes, while chimeras containing the PLCζ C2 domain exhibited PI(3)P binding. Our data suggest that the EF hands are not solely responsible for the nanomolar Ca(2+) sensitivity of PLCζ and that membrane PIP2 binding involves the C2 domain and XY-linker of PLCζ. To investigate the relationship between PLC enzymatic properties and Ca(2+) oscillations in eggs, we have developed a mathematical model that incorporates Ca(2+)-dependent InsP3 generation by the PLC chimeras and their levels of intracellular expression. These numerical simulations can for the first time predict the empirical variability in onset and frequency of Ca(2+) oscillatory activity associated with specific PLC variants.
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Affiliation(s)
- Maria Theodoridou
- Institute of Molecular and Experimental Medicine, WHRI, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
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Nomikos M, Kashir J, Swann K, Lai FA. Sperm PLCζ: from structure to Ca2+ oscillations, egg activation and therapeutic potential. FEBS Lett 2013; 587:3609-16. [PMID: 24157362 DOI: 10.1016/j.febslet.2013.10.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 10/12/2013] [Accepted: 10/14/2013] [Indexed: 10/26/2022]
Abstract
Significant evidence now supports the assertion that cytosolic calcium oscillations during fertilization in mammalian eggs are mediated by a testis-specific phospholipase C (PLC), termed PLC-zeta (PLCζ) that is released into the egg following gamete fusion. Herein, we describe the current paradigm of PLCζ in this fundamental biological process, summarizing recent important advances in our knowledge of the biochemical and physiological properties of this enzyme. We describe the data suggesting that PLCζ has distinct features amongst PLCs enabling the hydrolysis of its substrate, phosphatidylinositol 4,5-bisphosphate (PIP2) at low Ca(2+) levels. PLCζ appears to be unique in its ability to target PIP2 that is present on intracellular vesicles. We also discuss evidence that PLCζ may be a significant factor in human fertility with potential therapeutic capacity.
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Affiliation(s)
- Michail Nomikos
- Institute of Molecular and Experimental Medicine, WHRI, Cardiff University School of Medicine, Heath Park, CF144XN Cardiff, UK.
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Amdani SN, Jones C, Coward K. Phospholipase C zeta (PLCζ): oocyte activation and clinical links to male factor infertility. Adv Biol Regul 2013; 53:292-308. [PMID: 23916605 DOI: 10.1016/j.jbior.2013.07.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 07/08/2013] [Indexed: 06/02/2023]
Abstract
Mounting scientific and clinical evidence supports the key role played by phospholipase C zeta (PLCζ), a sperm-specific protein, in the activation of oocytes following fertilisation. Lacking a pleckstrin homology domain, PLCζ remains the smallest known mammalian PLC and was first identified in 2002. Since then, PLCζ has been the target for a multitude of studies in both mammalian and non-mammalian species focused upon its fundamental biochemical activity and crucial role as the mediator of oocyte activation. The earliest event subsequent to gamete fusion is the onset of a series of intracellular calcium oscillations within the oocyte, which are known to modulate cortical granule exocytosis, release meiotic arrest, regulate gene expression, recruit maternal mRNA, and initiate embryogenesis. Collectively these processes are known as 'oocyte activation' and together, represent a fundamental mechanism for early embryonic development. Evidence suggests that these processes are initiated and controlled by calcium release from ooplasmic sources in response to PLCζ activity via the inositol-1,4,5-triphosphate (IP3) pathway. While the biochemical action of PLCζ has been extensively studied, especially in relation to the EF-hands, X-Y linker, and C2 domain, all of which play critical roles for in vivo activity, there are still key gaps in our knowledge, particularly in terms of regulation and interaction with other proteins within the oocyte. Moreover, increasing clinical evidence has revealed a strong correlation between certain types of male infertility and the aberrant expression, localisation, structure and function of PLCζ in human sperm, particularly in cases of recurrent intracytoplasmic sperm injection (ICSI) failure, globozoospermia, and oocyte activation deficiency (OAD). In addition, two heterozygous substitution mutations have been identified in the coding sequence of PLCζ in one particular patient causing disruption to the catalytic X and Y domains and resulting in infertility. Although, such cases can be treated via the use of artificial oocyte activators (AOAs) such as calcium ionophores, significant concern remains over the use of such chemical agents, largely due to the fact that calcium release manifests as a single transient, rather than a series of oscillations as observed during normal fertilisation. Current interest in PLCζ is thus to develop a series of prognostic, diagnostic and therapeutic approaches which could first identify male patients that are deficient in PLCζ and then rescue oocyte activation ability via assisted reproductive technology (ART) and a pure, functionally-active, recombinant human PLCζ protein. While significant progress has been made in such areas over recent years, there is a clear need to translate scientific findings to clinical settings in order to maximise successful outcome for patients.
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Affiliation(s)
- Siti Nornadhirah Amdani
- Nuffield Department of Obstetrics & Gynaecology, University of Oxford, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, UK
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Kashir J, Deguchi R, Jones C, Coward K, Stricker SA. Comparative biology of sperm factors and fertilization-induced calcium signals across the animal kingdom. Mol Reprod Dev 2013; 80:787-815. [PMID: 23900730 DOI: 10.1002/mrd.22222] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/23/2013] [Indexed: 11/08/2022]
Abstract
Fertilization causes mature oocytes or eggs to increase their concentrations of intracellular calcium ions (Ca²⁺) in all animals that have been examined, and such Ca²⁺ elevations, in turn, provide key activating signals that are required for non-parthenogenetic development. Several lines of evidence indicate that the Ca²⁺ transients produced during fertilization in mammals and other taxa are triggered by soluble factors that sperm deliver into oocytes after gamete fusion. Thus, for a broad-based analysis of Ca²⁺ dynamics during fertilization in animals, this article begins by summarizing data on soluble sperm factors in non-mammalian species, and subsequently reviews various topics related to a sperm-specific phospholipase C, called PLCζ, which is believed to be the predominant activator of mammalian oocytes. After characterizing initiation processes that involve sperm factors or alternative triggering mechanisms, the spatiotemporal patterns of Ca²⁺ signals in fertilized oocytes or eggs are compared in a taxon-by-taxon manner, and broadly classified as either a single major transient or a series of repetitive oscillations. Both solitary and oscillatory types of fertilization-induced Ca²⁺ signals are typically propagated as global waves that depend on Ca²⁺ release from the endoplasmic reticulum in response to increased concentrations of inositol 1,4,5-trisphosphate (IP₃). Thus, for taxa where relevant data are available, upstream pathways that elevate intraoocytic IP3 levels during fertilization are described, while other less-common modes of producing Ca²⁺ transients are also examined. In addition, the importance of fertilization-induced Ca²⁺ signals for activating development is underscored by noting some major downstream effects of these signals in various animals.
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Affiliation(s)
- Junaid Kashir
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, UK
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Nomikos M, Yu Y, Elgmati K, Theodoridou M, Campbell K, Vassilakopoulou V, Zikos C, Livaniou E, Amso N, Nounesis G, Swann K, Lai FA. Phospholipase Cζ rescues failed oocyte activation in a prototype of male factor infertility. Fertil Steril 2013; 99:76-85. [PMID: 22999959 PMCID: PMC3540263 DOI: 10.1016/j.fertnstert.2012.08.035] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Revised: 08/15/2012] [Accepted: 08/20/2012] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To determine the effect of infertility-linked sperm phospholipase Cζ (PLCζ) mutations on their ability to trigger oocyte Ca(2+) oscillations and development, and also to evaluate the potential therapeutic utility of wild-type, recombinant PLCζ protein for rescuing failed oocyte activation and embryo development. DESIGN Test of a novel therapeutic approach to male factor infertility. SETTING University medical school research laboratory. PATIENT(S) Donated unfertilized human oocytes from follicle reduction. INTERVENTION(S) Microinjection of oocytes with recombinant human PLCζ protein or PLCζ cRNA and a Ca(2+)-sensitive fluorescent dye. MAIN OUTCOME MEASURE(S) Measurement of the efficacy of mutant and wild-type PLCζ-mediated enzyme activity, oocyte Ca(2+) oscillations, activation, and early embryo development. RESULT(S) In contrast to the wild-type protein, mutant forms of human sperm PLCζ display aberrant enzyme activity and a total failure to activate unfertilized oocytes. Subsequent microinjection of recombinant human PLCζ protein reliably triggers the characteristic pattern of cytoplasmic Ca(2+) oscillations at fertilization, which are required for normal oocyte activation and successful embryo development to the blastocyst stage. CONCLUSION(S) Dysfunctional sperm PLCζ cannot trigger oocyte activation and results in male factor infertility, so a potential therapeutic approach is oocyte microinjection of active, wild-type PLCζ protein. We have demonstrated that recombinant human PLCζ can phenotypically rescue failed activation in oocytes that express dysfunctional PLCζ, and that this intervention culminates in efficient blastocyst formation.
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Affiliation(s)
- Michail Nomikos
- Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom; National Center for Scientific Research "Demokritos," Aghia Paraskevi, Greece.
| | - Yuansong Yu
- Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom
| | - Khalil Elgmati
- Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom
| | - Maria Theodoridou
- Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom; National Center for Scientific Research "Demokritos," Aghia Paraskevi, Greece
| | - Karen Campbell
- IVF Wales, University Hospital of Wales, Heath Park, Cardiff, United Kingdom
| | | | - Christos Zikos
- National Center for Scientific Research "Demokritos," Aghia Paraskevi, Greece
| | - Evangelia Livaniou
- National Center for Scientific Research "Demokritos," Aghia Paraskevi, Greece
| | - Nazar Amso
- Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom
| | - George Nounesis
- National Center for Scientific Research "Demokritos," Aghia Paraskevi, Greece
| | - Karl Swann
- Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom
| | - F Anthony Lai
- Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom.
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Swann K, Lai FA. PLC? and the initiation of Ca2+ oscillations in fertilizing mammalian eggs. Cell Calcium 2013; 53:55-62. [DOI: 10.1016/j.ceca.2012.11.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 10/31/2012] [Accepted: 11/01/2012] [Indexed: 10/27/2022]
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