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Poidevin M, Mazuras N, Bontonou G, Delamotte P, Denis B, Devilliers M, Akiki P, Petit D, de Luca L, Soulie P, Gillet C, Wicker-Thomas C, Montagne J. A fatty acid anabolic pathway in specialized-cells sustains a remote signal that controls egg activation in Drosophila. PLoS Genet 2024; 20:e1011186. [PMID: 38483976 DOI: 10.1371/journal.pgen.1011186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 03/26/2024] [Accepted: 02/14/2024] [Indexed: 03/27/2024] Open
Abstract
Egg activation, representing the critical oocyte-to-embryo transition, provokes meiosis completion, modification of the vitelline membrane to prevent polyspermy, and translation of maternally provided mRNAs. This transition is triggered by a calcium signal induced by spermatozoon fertilization in most animal species, but not in insects. In Drosophila melanogaster, mature oocytes remain arrested at metaphase-I of meiosis and the calcium-dependent activation occurs while the oocyte moves through the genital tract. Here, we discovered that the oenocytes of fruitfly females are required for egg activation. Oenocytes, cells specialized in lipid-metabolism, are located beneath the abdominal cuticle. In adult flies, they synthesize the fatty acids (FAs) that are the precursors of cuticular hydrocarbons (CHCs), including pheromones. The oenocyte-targeted knockdown of a set of FA-anabolic enzymes, involved in very-long-chain fatty acid (VLCFA) synthesis, leads to a defect in egg activation. Given that some but not all of the identified enzymes are required for CHC/pheromone biogenesis, this putative VLCFA-dependent remote control may rely on an as-yet unidentified CHC or may function in parallel to CHC biogenesis. Additionally, we discovered that the most posterior ventral oenocyte cluster is in close proximity to the uterus. Since oocytes dissected from females deficient in this FA-anabolic pathway can be activated in vitro, this regulatory loop likely operates upstream of the calcium trigger. To our knowledge, our findings provide the first evidence that a physiological extra-genital signal remotely controls egg activation. Moreover, our study highlights a potential metabolic link between pheromone-mediated partner recognition and egg activation.
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Affiliation(s)
- Mickael Poidevin
- Institut for Integrative Biology of the Cell (I2BC), CNRS, Université Paris-Sud, CEA, Gif-sur-Yvette, France
| | - Nicolas Mazuras
- Laboratoire Evolution, Génomes, Comportements, Ecologie (EGCE), CNRS, IRD, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Gwénaëlle Bontonou
- Laboratoire Evolution, Génomes, Comportements, Ecologie (EGCE), CNRS, IRD, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Pierre Delamotte
- Institut for Integrative Biology of the Cell (I2BC), CNRS, Université Paris-Sud, CEA, Gif-sur-Yvette, France
| | - Béatrice Denis
- Laboratoire Evolution, Génomes, Comportements, Ecologie (EGCE), CNRS, IRD, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Maëlle Devilliers
- Institut for Integrative Biology of the Cell (I2BC), CNRS, Université Paris-Sud, CEA, Gif-sur-Yvette, France
| | - Perla Akiki
- Institut for Integrative Biology of the Cell (I2BC), CNRS, Université Paris-Sud, CEA, Gif-sur-Yvette, France
| | - Delphine Petit
- Institut for Integrative Biology of the Cell (I2BC), CNRS, Université Paris-Sud, CEA, Gif-sur-Yvette, France
| | - Laura de Luca
- Centre Médical Universitaire, Department of Cell Physiology and Metabolism, Geneva, Switzerland
| | - Priscilla Soulie
- Centre Médical Universitaire, Department of Cell Physiology and Metabolism, Geneva, Switzerland
| | - Cynthia Gillet
- Institut for Integrative Biology of the Cell (I2BC), CNRS, Université Paris-Sud, CEA, Gif-sur-Yvette, France
| | - Claude Wicker-Thomas
- Laboratoire Evolution, Génomes, Comportements, Ecologie (EGCE), CNRS, IRD, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Jacques Montagne
- Institut for Integrative Biology of the Cell (I2BC), CNRS, Université Paris-Sud, CEA, Gif-sur-Yvette, France
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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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3
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Shacfe G, Turko R, Syed HH, Masoud I, Tahmaz Y, Samhan LM, Alkattan K, Shafqat A, Yaqinuddin A. A DNA Methylation Perspective on Infertility. Genes (Basel) 2023; 14:2132. [PMID: 38136954 PMCID: PMC10743303 DOI: 10.3390/genes14122132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 11/24/2023] [Accepted: 11/25/2023] [Indexed: 12/24/2023] Open
Abstract
Infertility affects a significant number of couples worldwide and its incidence is increasing. While assisted reproductive technologies (ART) have revolutionized the treatment landscape of infertility, a significant number of couples present with an idiopathic cause for their infertility, hindering effective management. Profiling the genome and transcriptome of infertile men and women has revealed abnormal gene expression. Epigenetic modifications, which comprise dynamic processes that can transduce environmental signals into gene expression changes, may explain these findings. Indeed, aberrant DNA methylation has been widely characterized as a cause of abnormal sperm and oocyte gene expression with potentially deleterious consequences on fertilization and pregnancy outcomes. This review aims to provide a concise overview of male and female infertility through the lens of DNA methylation alterations.
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Affiliation(s)
| | | | | | | | | | | | | | - Areez Shafqat
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; (G.S.); (R.T.); (H.H.S.); (I.M.); (Y.T.); (L.M.S.); (K.A.); (A.Y.)
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4
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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: 0] [Impact Index Per Article: 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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6
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Chen F, Wang Y, He J, Smith C, Xue G, Zhao Y, Peng Y, Zhang J, Liu J, Chen J, Xie P. Alternative signal pathways underly fertilization and egg activation in a fish with contrasting modes of spawning. BMC Genomics 2023; 24:167. [PMID: 37016278 PMCID: PMC10074663 DOI: 10.1186/s12864-023-09244-1] [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: 10/11/2022] [Accepted: 03/13/2023] [Indexed: 04/06/2023] Open
Abstract
BACKGROUND The processes of fertilization and egg activation are vital for early embryogenesis. However, while the mechanisms associated with key events during these processes differ among species and modes of spawning, the signal pathways underlying these processes are opaque for many fishes, including economically important species. RESULTS We investigated phenotypic traits, ultrastructure and protein expression levels in the eggs of the topmouth culter (Culter alburnus), a protected and economically important freshwater fish that exhibits two spawning modes, producing semi-buoyant eggs and adhesive eggs. Unfertilized eggs of C. alburnus were examined, as well as eggs at fertilization and 30 min post fertilization. Our results showed that in semi-buoyant eggs, energy metabolism was activated at fertilization, followed by elevated protein expression of cytoskeleton and extracellular matrix (ECM)-receptor interactions that resulted in rapid egg swelling; a recognized adaptation for lotic habitats. In contrast, in adhesive eggs fertilization initiated the process of sperm-egg fusion and blocking of polyspermy, followed by enhanced protein expression of lipid metabolism and the formation of egg envelope adhesion and hardening, which are adaptive in lentic habitats. CONCLUSION Our findings indicate that alternative signal pathways differ between modes of spawning and timing during the key processes of fertilization and egg activation, providing new insights into the molecular mechanisms involved in adaptive early embryonic development in teleost fishes.
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Affiliation(s)
- Feng Chen
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Donghu Experimental Station of Lake Ecosystems, Chinese Academy of Sciences, 430072, Wuhan, China
| | - Yeke Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Donghu Experimental Station of Lake Ecosystems, Chinese Academy of Sciences, 430072, Wuhan, China
- Life Sciences Institute, Zhejiang University, 310058, Hangzhou, China
| | - Jun He
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Donghu Experimental Station of Lake Ecosystems, Chinese Academy of Sciences, 430072, Wuhan, China
| | - Carl Smith
- Department of Ecology and Vertebrate Zoology, University of Łódź, Łódź, Poland
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Brno, Czech Republic
| | - Ge Xue
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Donghu Experimental Station of Lake Ecosystems, Chinese Academy of Sciences, 430072, Wuhan, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Yan Zhao
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Donghu Experimental Station of Lake Ecosystems, Chinese Academy of Sciences, 430072, Wuhan, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Yanghui Peng
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Donghu Experimental Station of Lake Ecosystems, Chinese Academy of Sciences, 430072, Wuhan, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Jia Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Donghu Experimental Station of Lake Ecosystems, Chinese Academy of Sciences, 430072, Wuhan, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Jiarui Liu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Donghu Experimental Station of Lake Ecosystems, Chinese Academy of Sciences, 430072, Wuhan, China
| | - Jun Chen
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Donghu Experimental Station of Lake Ecosystems, Chinese Academy of Sciences, 430072, Wuhan, China.
| | - Ping Xie
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Donghu Experimental Station of Lake Ecosystems, Chinese Academy of Sciences, 430072, Wuhan, China.
- Institute of Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environment, Yunnan University, 650500, Kunming, China.
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7
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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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9
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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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10
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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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11
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Aras-Tosun D, Cakar Z, Can A, Ozkavukcu S, Kaplanoglu I, Cinar O. Phospholipase C-zeta levels are not correlated with fertilisation rates in infertile couples. Andrologia 2021; 54:e14269. [PMID: 34651330 DOI: 10.1111/and.14269] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 09/20/2021] [Accepted: 09/22/2021] [Indexed: 11/29/2022] Open
Abstract
In mammals, 'oocyte activation' is triggered by certain proteins, one of which is phospholipase C-zeta. Recent evidence suggests that low expression of phospholipase C-zeta might be associated with male infertility, while a limited number of studies claimed the opposite. This study was designed to test whether quantity of phospholipase C-zeta and in vitro fertilisation rates are correlated or not, assessed by flow cytometry. Semen samples from 43 infertile couples were analysed for the percentage and mean fluorescent intensity (MFI) of phospholipase C-zeta protein. Results were confirmed by immunofluorescent labelling. Patients with a fertilisation rate of 40% or lower were involved in the low fertilisation group, while the high fertilization group consisted of patients with a fertilisation rate of 60% and higher. Quantitative analyses by flow cytometry showed no significant difference among the low fertilisation and high fertilisation groups when phospholipase C-zeta ratio or MFI was considered. No correlation was found between pregnancy rates and phospholipase C-zeta quantity. None of the total fertilisation failure cases were lack of phospholipase C-zeta. In fact, fertilisation was possible even when phospholipase C-zeta levels were very low. Thus, we concluded that phospholipase C-zeta quantity cannot be considered as a diagnostic tool for male infertility.
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Affiliation(s)
- Duru Aras-Tosun
- Department of Histology and Embryology, Ankara University School of Dentistry, Ankara, Turkey
| | - Zeynep Cakar
- Department of Histology and Embryology, Ankara University School of Medicine, Ankara, Turkey
| | - Alp Can
- Department of Histology and Embryology, Ankara University School of Medicine, Ankara, Turkey
| | - Sinan Ozkavukcu
- Department of Histology and Embryology, Ankara University School of Medicine, Ankara, Turkey.,Centre for Assisted Reproduction, Ankara University School of Medicine, Ankara, Turkey
| | - Iskender Kaplanoglu
- Centre for Assisted Reproductive Medicine, TCSB Etlik Zubeyde Hanim Women's Health Teaching and Research Hospital, Ankara, Turkey
| | - Ozgur Cinar
- Department of Histology and Embryology, Ankara University School of Medicine, Ankara, Turkey.,Centre for Assisted Reproduction, Ankara University School of Medicine, Ankara, Turkey
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12
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Zhang ZP, Zhang JT, Huang SC, He XY, Deng LX. Double sperm cloning (DSC) is a promising strategy in mammalian genetic engineering and stem cell research. Stem Cell Res Ther 2020; 11:388. [PMID: 32894201 PMCID: PMC7487873 DOI: 10.1186/s13287-020-01907-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 08/12/2020] [Accepted: 08/27/2020] [Indexed: 12/14/2022] Open
Abstract
Embryonic stem cells (ESCs) derived from somatic cell nuclear transfer (SCNT) and induced pluripotent stem cells (iPSCs) are promising tools for meeting the personalized requirements of regenerative medicine. However, some obstacles need to be overcome before clinical trials can be undertaken. First, donor cells vary, and the reprogramming procedures are diverse, so standardization is a great obstacle regarding SCNT and iPSCs. Second, somatic cells derived from a patient may carry mitochondrial DNA mutations and exhibit telomere instability with aging or disease, and SCNT-ESCs and iPSCs retain the epigenetic memory or epigenetic modification errors. Third, reprogramming efficiency has remained low. Therefore, in addition to improving their success rate, other alternatives for producing ESCs should be explored. Producing androgenetic diploid embryos could be an outstanding strategy; androgenic diploid embryos are produced through double sperm cloning (DSC), in which two capacitated sperms (XY or XX, sorted by flow cytometer) are injected into a denucleated oocyte by intracytoplasmic sperm injection (ICSI) to reconstruct embryo and derive DSC-ESCs. This process could avoid some potential issues, such as mitochondrial interference, telomere shortening, and somatic epigenetic memory, all of which accompany somatic donor cells. Oocytes are naturally activated by sperm, which is unlike the artificial activation that occurs in SCNT. The procedure is simple and practical and can be easily standardized. In addition, DSC-ESCs can overcome ethical concerns and resolve immunological response matching with sperm providers. Certainly, some challenges must be faced regarding imprinted genes, epigenetics, X chromosome inactivation, and dosage compensation. In mice, DSC-ESCs have been produced and have shown excellent differentiation ability. Therefore, the many advantages of DSC make the study of this process worthwhile for regenerative medicine and animal breeding.
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Affiliation(s)
- Zhi-Ping Zhang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, China
| | - Jun-Tao Zhang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, China
| | - Shu-Cheng Huang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, China
| | - Xiu-Yuan He
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, China
| | - Li-Xin Deng
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, China.
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13
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Hu Q, Wolfner MF. Regulation of Trpm activation and calcium wave initiation during Drosophila egg activation. Mol Reprod Dev 2020; 87:880-886. [PMID: 32735035 DOI: 10.1002/mrd.23403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/24/2020] [Accepted: 07/15/2020] [Indexed: 12/12/2022]
Abstract
The transition from a developmentally arrested mature oocyte to a developing embryo requires a series of highly conserved events, collectively known as egg activation. All of these events are preceded by a ubiquitous rise of intracellular calcium, which results from influx of external calcium and/or calcium release from internal storage. In Drosophila, this calcium rise initiates from the pole(s) of the oocyte by influx of external calcium in response to mechanical triggers. It is thought to trigger calcium responsive kinases and/or phosphatases, which in turn alter the oocyte phospho-proteome to initiate downstream events. Recent studies revealed that external calcium enters the activating Drosophila oocyte through Trpm channels, a feature conserved in mouse. The local entry of calcium raises the question of whether Trpm channels are found locally at the poles of the oocyte or are localized around the oocyte periphery, but activated only at the poles. Here, we show that Trpm is distributed all around the oocyte. This requires that it thus be specially regulated at the poles to allow calcium wave initiation. We show that neither egg shape nor local pressure is sufficient to explain this local activation of Trpm channels.
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Affiliation(s)
- Qinan Hu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York
| | - Mariana F Wolfner
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York
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14
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Hu Q, Duncan FE, Nowakowski AB, Antipova OA, Woodruff TK, O'Halloran TV, Wolfner MF. Zinc Dynamics during Drosophila Oocyte Maturation and Egg Activation. iScience 2020; 23:101275. [PMID: 32615472 PMCID: PMC7330606 DOI: 10.1016/j.isci.2020.101275] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/30/2020] [Accepted: 06/11/2020] [Indexed: 12/13/2022] Open
Abstract
Temporal fluctuations in zinc concentration are essential signals, including during oogenesis and early embryogenesis. In mammals, zinc accumulation and release are required for oocyte maturation and egg activation, respectively. Here, we demonstrate that zinc flux occurs in Drosophila oocytes and activated eggs, and that zinc is required for female fertility. Our synchrotron-based X-ray fluorescence microscopy reveals zinc as the most abundant transition metal in Drosophila oocytes. Its levels increase during oocyte maturation, accompanied by the appearance of zinc-enriched intracellular granules in the oocyte, which depend on transporters. Subsequently, in egg activation, which mediates the transition from oocyte to embryo, oocyte zinc levels decrease significantly, as does the number of zinc-enriched granules. This pattern of zinc dynamics in Drosophila oocytes follows a similar trajectory to that in mammals, extending the parallels in female gamete processes between Drosophila and mammals and establishing Drosophila as a model for dissecting reproductive roles of zinc.
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Affiliation(s)
- Qinan Hu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Francesca E Duncan
- Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Andrew B Nowakowski
- The Chemistry of Life Processes Institute, Northwestern University, Evanston, IL 60208, USA; Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
| | - Olga A Antipova
- X-ray Sciences Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Teresa K Woodruff
- Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; The Chemistry of Life Processes Institute, Northwestern University, Evanston, IL 60208, USA; Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
| | - Thomas V O'Halloran
- The Chemistry of Life Processes Institute, Northwestern University, Evanston, IL 60208, USA; Department of Chemistry, Northwestern University, Evanston, IL 60208, USA; Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
| | - Mariana F Wolfner
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
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15
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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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16
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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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17
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Hu Q, Vélez-Avilés AN, Wolfner MF. Drosophila Plc21C is involved in calcium wave propagation during egg activation. MICROPUBLICATION BIOLOGY 2020; 2020. [PMID: 32550503 PMCID: PMC7252351 DOI: 10.17912/micropub.biology.000235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Qinan Hu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Adriana N Vélez-Avilés
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.,University of Puerto Rico-Río Piedras, Río Piedras, PR
| | - Mariana F Wolfner
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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18
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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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19
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Abstract
Phospholipase C (PLC) family members constitute a family of diverse enzymes. Thirteen different family members have been cloned. These family members have unique structures that mediate various functions. Although PLC family members all appear to signal through the bi-products of cleaving phospholipids, it is clear that each family member, and at times each isoform, contributes to unique cellular functions. This chapter provides a review of the current literature on PLC. In addition, references have been provided for more in-depth information regarding areas that are not discussed including tyrosine kinase activation of PLC. Understanding the roles of the individual PLC enzymes, and their distinct cellular functions, will lead to a better understanding of the physiological roles of these enzymes in the development of diseases and the maintenance of homeostasis.
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20
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York-Andersen AH, Hu Q, Wood BW, Wolfner MF, Weil TT. A calcium-mediated actin redistribution at egg activation in Drosophila. Mol Reprod Dev 2019; 87:293-304. [PMID: 31880382 PMCID: PMC7044060 DOI: 10.1002/mrd.23311] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 12/12/2019] [Indexed: 12/24/2022]
Abstract
Egg activation is the essential process in which mature oocytes gain the competency to proceed into embryonic development. Many events of egg activation are conserved, including an initial rise of intracellular calcium. In some species, such as echinoderms and mammals, changes in the actin cytoskeleton occur around the time of fertilization and egg activation. However, the interplay between calcium and actin during egg activation remains unclear. Here, we use imaging, genetics, pharmacological treatment, and physical manipulation to elucidate the relationship between calcium and actin in living Drosophila eggs. We show that, before egg activation, actin is smoothly distributed between ridges in the cortex of the dehydrated mature oocytes. At the onset of egg activation, we observe actin spreading out as the egg swells though the intake of fluid. We show that a relaxed actin cytoskeleton is required for the intracellular rise of calcium to initiate and propagate. Once the swelling is complete and the calcium wave is traversing the egg, it leads to a reorganization of actin in a wavelike manner. After the calcium wave, the actin cytoskeleton has an even distribution of foci at the cortex. Together, our data show that calcium resets the actin cytoskeleton at egg activation, a model that we propose to be likely conserved in other species.
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Affiliation(s)
| | - Qinan Hu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York
| | - Benjamin W Wood
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Mariana F Wolfner
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York
| | - Timothy T Weil
- Department of Zoology, University of Cambridge, Cambridge, UK
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21
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Polyspermy-preventing mechanisms in sea urchin eggs: New developments for an old problem. Biochem Biophys Res Commun 2019; 520:695-698. [DOI: 10.1016/j.bbrc.2019.10.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 10/01/2019] [Indexed: 12/21/2022]
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22
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Hu Q, Wolfner MF. The Drosophila Trpm channel mediates calcium influx during egg activation. Proc Natl Acad Sci U S A 2019; 116:18994-19000. [PMID: 31427540 PMCID: PMC6754564 DOI: 10.1073/pnas.1906967116] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Egg activation is the process in which mature oocytes are released from developmental arrest and gain competency for embryonic development. In Drosophila and other arthropods, eggs are activated by mechanical pressure in the female reproductive tract, whereas in most other species, eggs are activated by fertilization. Despite the difference in the trigger, Drosophila shares many conserved features with higher vertebrates in egg activation, including a rise of intracellular calcium in response to the trigger. In Drosophila, this calcium rise is initiated by entry of extracellular calcium due to opening of mechanosensitive ion channels and initiates a wave that passes across the egg prior to initiation of downstream activation events. Here, we combined inhibitor tests, germ-line-specific RNAi knockdown, and germ-line-specific CRISPR/Cas9 knockout to identify the Transient Receptor Potential (TRP) channel subfamily M (Trpm) as a critical channel that mediates the calcium influx and initiates the calcium wave during Drosophila egg activation. We observed a reduction in the proportion of eggs that hatched from trpm germ-line knockout mutant females, although eggs were able to complete some egg activation events including cell cycle resumption. Since a mouse ortholog of Trpm was recently reported also to be involved in calcium influx during egg activation and in further embryonic development, our results suggest that calcium uptake from the environment via TRPM channels is a deeply conserved aspect of egg activation.
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Affiliation(s)
- Qinan Hu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Mariana F Wolfner
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
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23
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Follo MY, Ratti S, Manzoli L, Ramazzotti G, Faenza I, Fiume R, Mongiorgi S, Suh PG, McCubrey JA, Cocco L. Inositide-Dependent Nuclear Signalling in Health and Disease. Handb Exp Pharmacol 2019; 259:291-308. [PMID: 31889219 DOI: 10.1007/164_2019_321] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Nuclear inositides have a specific subcellular distribution that is linked to specific functions; thus their regulation is fundamental both in health and disease. Emerging evidence shows that alterations in multiple inositide signalling pathways are involved in pathophysiology, not only in cancer but also in other diseases. Here, we give an overview of the main features of inositides in the cell, and we discuss their potential as new molecular therapeutic targets.
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Affiliation(s)
- Matilde Y Follo
- Cellular Signalling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Stefano Ratti
- Cellular Signalling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Lucia Manzoli
- Cellular Signalling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Giulia Ramazzotti
- Cellular Signalling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Irene Faenza
- Cellular Signalling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Roberta Fiume
- Cellular Signalling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Sara Mongiorgi
- Cellular Signalling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Pann Ghill Suh
- Korea Brain Research Institute, Daegu, Republic of Korea.,School of Life Sciences, UNIST, Ulsan, Republic of Korea
| | - James A McCubrey
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Lucio Cocco
- Cellular Signalling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
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Anifandis G, Michopoulos A, Daponte A, Chatzimeletiou K, Simopoulou M, Messini CI, Polyzos NP, Vassiou K, Dafopoulos K, Goulis DG. Artificial oocyte activation: physiological, pathophysiological and ethical aspects. Syst Biol Reprod Med 2018; 65:3-11. [DOI: 10.1080/19396368.2018.1516000] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- George Anifandis
- Department of Obstetrics and Gynecology, ART Unit, University of Thessaly, School of Health Sciences, Faculty of Medicine, Larisa, Greece
| | - Alexandros Michopoulos
- Unit of Reproductive Endocrinology, 1st Department of Obstetrics and Gynecology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Alexandros Daponte
- Department of Obstetrics and Gynecology, ART Unit, University of Thessaly, School of Health Sciences, Faculty of Medicine, Larisa, Greece
| | - Katerina Chatzimeletiou
- Unit of Human Reproduction, 1st Department of Obstetrics and Gynecology, Aristotle University Medical School, Papageorgiou General Hospital, Thessaloniki, Greece
| | - Mara Simopoulou
- Department of Physiology, Kapodistrian University of Athens, School of Health Sciences, Faculty of Medicine, Athens, Greece
| | - Christina I. Messini
- Department of Obstetrics and Gynecology, ART Unit, University of Thessaly, School of Health Sciences, Faculty of Medicine, Larisa, Greece
| | - Nikolas P. Polyzos
- Vrije Universiteit Brussel, Brussels, Belgium
- Universitair Ziekenhuis Brussel, Brussels, Belgium
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Katerina Vassiou
- Department of Anatomy, University of Thessaly, School of Health Sciences, Faculty of Medicine, Larisa, Greece
| | - Konstantinos Dafopoulos
- Department of Obstetrics and Gynecology, ART Unit, University of Thessaly, School of Health Sciences, Faculty of Medicine, Larisa, Greece
| | - Dimitrios G. Goulis
- Unit of Reproductive Endocrinology, 1st Department of Obstetrics and Gynecology, Aristotle University of Thessaloniki, Thessaloniki, Greece
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A novel mutation in the TUBB8 gene is associated with complete cleavage failure in fertilized eggs. J Assist Reprod Genet 2018; 35:1349-1356. [PMID: 29704226 DOI: 10.1007/s10815-018-1188-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 04/13/2018] [Indexed: 01/08/2023] Open
Abstract
PURPOSE Cleavage of the zygote during human reproduction is a key event of early embryonic development. The genetic events associated with idiopathic embryonic cleavage failure are not certain. Mutations in the tubulin beta 8 class VIII (TUBB8) gene have been reported to be associated with oocyte maturation, fertilization, and developmental arrest. Here, we aimed to assess the clinical and genetic characteristics of complete cleavage failure in fertilized eggs. METHODS We have characterized a patient with a 9-year history of primary infertility in a non-consanguineous family from China. The patient presented complete cleavage failure in all two-pronuclear (2PN) fertilized oocytes after 2 cycles of in vitro fertilization (IVF). We performed Sanger sequencing of the TUBB8 gene in the patient, and further bioinformatics analysis to identify pathogenesis of gene. RESULTS A novel homozygous mutation, c.322G > A (p.Glu108Lys), was detected, and this change was absent from 179 control subjects. Glutamic acid is highly conserved at this position, and replacement by lysine was predicted to be repelled by the α-tubulin positive region, disrupting the α-β tubulin interaction. CONCLUSIONS Our findings presented a homozygous mutation of TUBB8 associated with complete cleavage failure in fertilized eggs and provided new data for the genotype-phenotype of TUBB8-related diseases.
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Dehydroepiandrosterone (DHEA) and Its Sulfate (DHEA-S) in Mammalian Reproduction: Known Roles and Novel Paradigms. VITAMINS AND HORMONES 2018; 108:223-250. [PMID: 30029728 DOI: 10.1016/bs.vh.2018.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Steroid hormones form an integral part of normal development in mammalian organisms. Cholesterol is the parent compound from which all steroid hormones are synthesized. The product pregnenolone formed from cholesterol serves as precursor for mineralocorticoids, glucocorticoids, as well as dehydroepiandrosterone (DHEA) and its derived sexual hormones. DHEA assumes the prohormone status of a predominant endogenous precursor and a metabolic intermediate in ovarian follicular steroidogenesis. DHEA supplementation has been used to enhance ovarian reserve. Steroids like estradiol and testosterone have long been contemplated to play important roles in regulating meiotic maturation of oocytes in conjunction with gonadotropins. It is known that oocyte priming with estrogen is necessary to develop calcium (Ca2+) oscillations during maturation. Accruing evidence from diverse studies suggests that DHEA and its sulfate (dehydroepiandrosterone sulfate, DHEA-S) play significantly vital role not only as intermediates in androgen and estrogen formation, but may also be the probable 'oocyte factor' and behave as endogenous agonists triggering calcium oscillations for oocyte activation. DHEA/DHEA-S have been reported to regulate calcium channels for the passage of Ca2+ through the oocyte cytoplasm and for maintaining required threshold of Ca2+ oscillations. This role of DHEA/DHEA-S assumes critical significance in assisted reproductive technology and in-vitro fertilization treatment cycles where physical, chemical, and mechanical methods are employed for artificial oocyte activation to enhance fertilization rates. However, since these methods are invasive and may also cause adverse epigenetic modifications; oral or culture-media supplementation with DHEA/DHEA-S provides a noninvasive innate mechanism of in-vitro oocyte activation based on physiological metabolic pathway.
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Universality and Diversity of a Fast, Electrical Block to Polyspermy During Fertilization in Animals. DIVERSITY AND COMMONALITY IN ANIMALS 2018. [DOI: 10.1007/978-4-431-56609-0_24] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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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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29
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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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30
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Abstract
The migration pattern of sperm-specific phospholipase C-ζ (PLC-ζ) was followed and the role of this migration in actin cytoskeleton dynamics was determined. We investigated whether PLC-ζ exits sperm, opening the possibility that PLC-ζ is the 'spermatozoidal activator factor' (SOAF). As capacitation progresses, the highly dynamic actin cytoskeleton bound different proteins to regulate their location and activity. PLC-ζ participation at the start of fertilization was established. In non-capacitated spermatozoa, PLC-ζ is in the perinuclear theca (PT) and in the flagellum, therefore it was decided to determine whether bovine sperm actin interacts with PLC-ζ to direct its relocation as it progresses from non-capacitated (NC) to capacitated (C) and to acrosome-reacted (AR) spermatozoa. PLC-ζ interacted with actin in NC spermatozoa (100%), PLC-ζ levels decreased in C spermatozoa to 32% and in AR spermatozoa to 57% (P < 0.001). The level of actin/PLC-ζ interaction was twice as high in G-actin (P < 0.001) that reflected an increase in affinity. Upon reaching the AR spermatozoa, PLC-ζ was partially released from the cell. It was concluded that actin cytoskeleton dynamics control the migration of PLC-ζ during capacitation and leads to its partial release at AR spermatozoa. It is suggested that liberated PLC-ζ could reach the egg and favour fertilization.
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31
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Ozil JP, Sainte-Beuve T, Banrezes B. [Mg 2+] o/[Ca 2+] o determines Ca 2+ response at fertilization: tuning of adult phenotype? Reproduction 2017; 154:675-693. [PMID: 28851827 DOI: 10.1530/rep-16-0057] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 08/15/2017] [Accepted: 08/29/2017] [Indexed: 01/09/2023]
Abstract
Alteration of the postnatal phenotype has sparked great concern about the developmental impact of culture media used at fertilization. However, the mechanisms and compounds involved are yet to be determined. Here, we used the Ca2+ responses from mouse eggs fertilized by ICSI as a dynamic and quantitative marker to understand the role of compounds in egg functioning and establish possible correlations with adult phenotypes. We computed 134 Ca2+ responses from the first to the last oscillation in media with specific formulations. Analyses demonstrate that eggs generated two times as many Ca2+ oscillations in KSOM as in M16 media (18.8 ± 7.0 vs 9.2 ± 2.5). Moreover, the time increment of the delay between two consecutive oscillations, named TIbO, is the most sensitive coefficient characterizing the mechanism that paces Ca2+ oscillations once the egg has been fertilized. Neither doubling external free Ca2+ nor dispermic fertilization increased significantly the total number of Ca2+ oscillations. In contrast, removing Mg2+ from the M16 boosted Ca2+ oscillations to 54.0 ± 35.2. Hence, [Mg2+]o/[Ca2+]o appears to determine the number, duration and frequency of the Ca2+ oscillations. These changes were correlated with long-term effects. The rate of female's growth was impacted with the 'KSOM' females having only half the fat deposit of 'M16' females. Moreover, adult animals issued from M16 had significantly smaller brain weight vs 'KSOM' and 'control' animals. TIbO is a new Ca2+ coefficient that gauges the very early functional impact of culture media. It offers the possibility of establishing correlations with postnatal consequences according to IVF medium formulation.Free French abstract: A French translation of this abstract is freely available at http://www.reproduction-online.org/content/154/5/675/suppl/DC2.
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Affiliation(s)
- Jean-Pierre Ozil
- UMR BDR, INRA, ENVA, Université Paris Saclay, Jouy en Josas, France
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Male infertility-linked point mutation reveals a vital binding role for the C2 domain of sperm PLCζ. Biochem J 2017; 474:1003-1016. [PMID: 28270562 DOI: 10.1042/bcj20161057] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 01/05/2017] [Accepted: 01/20/2017] [Indexed: 12/14/2022]
Abstract
Sperm-specific phospholipase C zeta (PLCζ) is widely considered to be the physiological stimulus that evokes intracellular calcium (Ca2+) oscillations that are essential for the initiation of egg activation during mammalian fertilisation. A recent genetic study reported a male infertility case that was directly associated with a point mutation in the PLCζ C2 domain, where an isoleucine residue had been substituted with a phenylalanine (I489F). Here, we have analysed the effect of this mutation on the in vivo Ca2+ oscillation-inducing activity and the in vitro biochemical properties of human PLCζ. Microinjection of cRNA or recombinant protein corresponding to PLCζI489F mutant at physiological concentrations completely failed to cause Ca2+ oscillations and trigger development. However, this infertile phenotype could be effectively rescued by microinjection of relatively high (non-physiological) amounts of recombinant mutant PLCζI489F protein, leading to Ca2+ oscillations and egg activation. Our in vitro biochemical analysis suggested that the PLCζI489F mutant displayed similar enzymatic properties, but dramatically reduced binding to PI(3)P and PI(5)P-containing liposomes compared with wild-type PLCζ. Our findings highlight the importance of PLCζ at fertilisation and the vital role of the C2 domain in PLCζ function, possibly due to its novel binding characteristics.
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Gao LL, Zhou CX, Zhang XL, Liu P, Jin Z, Zhu GY, Ma Y, Li J, Yang ZX, Zhang D. ZP3 is Required for Germinal Vesicle Breakdown in Mouse Oocyte Meiosis. Sci Rep 2017; 7:41272. [PMID: 28145526 PMCID: PMC5286536 DOI: 10.1038/srep41272] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 12/19/2016] [Indexed: 12/23/2022] Open
Abstract
ZP3 is a principal component of the zona pellucida (ZP) of mammalian oocytes and is essential for normal fertility, and knockout of ZP3 causes complete infertility. ZP3 promotes fertilization by recognizing sperm binding and activating the acrosome reaction; however, additional cellular roles for ZP3 in mammalian oocytes have not been yet reported. In the current study, we found that ZP3 was strongly expressed in the nucleus during prophase and gradually translocated to the ZP. Knockdown of ZP3 by a specific siRNA dramatically inhibited germinal vesicle breakdown (GVBD) (marking the beginning of meiosis), significantly reducing the percentage of MII oocytes. To investigate the ZP3-mediated mechanisms governing GVBD, we identified potential ZP3-interacting proteins by immunoprecipitation and mass spectrometry. We identified Protein tyrosine phosphatase, receptor type K (Ptprk), Aryl hydrocarbon receptor-interacting protein-like 1 (Aipl1), and Diaphanous related formin 2 (Diaph2) as potential candidates, and established a working model to explain how ZP3 affects GVBD. Finally, we provided preliminary evidence that ZP3 regulates Akt phosphorylation, lamin binding to the nuclear membrane via Aipl1, and organization of the actin cytoskeleton via Diaph2. These findings contribute to our understanding of a novel role played by ZP3 in GVBD.
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Affiliation(s)
- Lei-Lei Gao
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Chun-Xiang Zhou
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Xiao-Lan Zhang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Peng Liu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Zhen Jin
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Gang-Yi Zhu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Yang Ma
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Jing Li
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Zhi-Xia Yang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Dong Zhang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
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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
Compared with the animal kingdom, fertilization is particularly complex in flowering plants (angiosperms). Sperm cells of angiosperms have lost their motility and require transportation as a passive cargo by the pollen tube cell to the egg apparatus (egg cell and accessory synergid cells). Sperm cell release from the pollen tube occurs after intensive communication between the pollen tube cell and the receptive synergid, culminating in the lysis of both interaction partners. Following release of the two sperm cells, they interact and fuse with two dimorphic female gametes (the egg and the central cell) forming the major seed components embryo and endosperm, respectively. This process is known as double fertilization. Here, we review the current understanding of the processes of sperm cell reception, gamete interaction, their pre-fertilization activation and fusion, as well as the mechanisms plants use to prevent the fusion of egg cells with multiple sperm cells. The role of Ca(2+) is highlighted in these various processes and comparisons are drawn between fertilization mechanisms in flowering plants and other eukaryotes, including mammals.
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Affiliation(s)
- Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93040 Regensburg, Germany.
| | - Stefanie Sprunck
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93040 Regensburg, Germany
| | - Gary M Wessel
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02912, USA
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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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Tosti E, Ménézo Y. Gamete activation: basic knowledge and clinical applications. Hum Reprod Update 2016; 22:420-39. [PMID: 27278231 PMCID: PMC4917743 DOI: 10.1093/humupd/dmw014] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 04/01/2016] [Indexed: 01/07/2023] Open
Abstract
Background The first clues to the process of gamete activation date back to nearly 60 years ago. The mutual activation of gametes is a crucial event during fertilization. In the testis and ovaries, spermatozoa and oocytes are in a state of meiotic and metabolic quiescence and require reciprocal signals in order to undergo functional changes that lead to competence for fertilization. First, the oocyte activates sperm by triggering motility, chemoattraction, binding and the acrosome reaction, culminating with the fusion of the two plasma membranes. At the end of this cascade of events, collectively known as sperm capacitation, sperm-induced oocyte activation occurs, generating electrical, morphological and metabolic modifications in the oocyte. Objective and rationale The aim of this review is to provide the current state of knowledge regarding the entire process of gamete activation in selected specific animal models that have contributed to our understanding of fertilization in mammals, including humans. Here we describe in detail the reciprocal induction of the two activation processes, the molecules involved and the mechanisms of cell interaction and signal transduction that ultimately result in successful embryo development and creation of a new individual. Search methods We carried out a literature survey with no restrictions on publication date (from the early 1950s to March 2016) using PubMed/Medline, Google Scholar and Web of Knowledge by utilizing common keywords applied in the field of fertilization and embryo development. We also screened the complete list of references published in the most recent research articles and relevant reviews published in English (both animal and human studies) on the topics investigated. Outcomes Literature on the principal animal models demonstrates that gamete activation is a pre-requisite for successful fertilization, and is a process common to all species studied to date. We provide a detailed description of the dramatic changes in gamete morphology and behavior, the regulatory molecules triggering gamete activation and the intracellular ions and second messengers involved in active metabolic pathways in different species. Recent scientific advances suggest that artificial gamete activation may represent a novel technique to improve human IVF outcomes, but this approach requires caution. Wider implications Although controversial, manipulation of gamete activation represents a promising tool for ameliorating the fertilization rate in assisted reproductive technologies. A better knowledge of mechanisms that transform the quiescent oocyte into a pluripotent cell may also provide new insights for the clinical use of stem cells.
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Affiliation(s)
- Elisabetta Tosti
- Stazione Zoologica Anton Dohrn, Villa Comunale, Naples 80121, Italy
| | - Yves Ménézo
- London Fertility Associates, 104 Harley Street, London WIG7JD, UK
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Krauchunas AR, Marcello MR, Singson A. The molecular complexity of fertilization: Introducing the concept of a fertilization synapse. Mol Reprod Dev 2016; 83:376-86. [PMID: 26970099 DOI: 10.1002/mrd.22634] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 02/22/2016] [Indexed: 01/27/2023]
Abstract
The details of sperm-egg interactions remain a relative mystery despite many decades of research. As new molecular complexities are being discovered, we need to revise the framework in which we think about fertilization. As such, we propose that fertilization involves the formation of a synapse between the sperm and egg. A cellular synapse is a structure that mediates cell adhesion, signaling, and secretion through specialized zones of interaction and polarity. In this review, we draw parallels between the immune synapse and fertilization, and argue that we should consider sperm-egg recognition, binding, and fusion in the context of a "fertilization synapse." Mol. Reprod. Dev. 83: 376-386, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Amber R Krauchunas
- Waksman Institute of Microbiology, Rutgers University, Piscataway, New Jersey
| | | | - Andrew Singson
- Waksman Institute of Microbiology, Rutgers University, Piscataway, New Jersey
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The zinc spark is an inorganic signature of human egg activation. Sci Rep 2016; 6:24737. [PMID: 27113677 PMCID: PMC4845039 DOI: 10.1038/srep24737] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 04/01/2016] [Indexed: 12/04/2022] Open
Abstract
Egg activation refers to events required for transition of a gamete into an embryo, including establishment of the polyspermy block, completion of meiosis, entry into mitosis, selective recruitment and degradation of maternal mRNA, and pronuclear development. Here we show that zinc fluxes accompany human egg activation. We monitored calcium and zinc dynamics in individual human eggs using selective fluorophores following activation with calcium-ionomycin, ionomycin, or hPLCζ cRNA microinjection. These egg activation methods, as expected, induced rises in intracellular calcium levels and also triggered the coordinated release of zinc into the extracellular space in a prominent “zinc spark.” The ability of the gamete to mount a zinc spark response was meiotic-stage dependent. Moreover, chelation of intracellular zinc alone was sufficient to induce cell cycle resumption and transition of a meiotic cell into a mitotic one. Together, these results demonstrate critical functions for zinc dynamics and establish the zinc spark as an extracellular marker of early human development.
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Takayama J, Onami S. The Sperm TRP-3 Channel Mediates the Onset of a Ca 2+ Wave in the Fertilized C. elegans Oocyte. Cell Rep 2016; 15:625-637. [DOI: 10.1016/j.celrep.2016.03.040] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 02/02/2016] [Accepted: 03/10/2016] [Indexed: 11/17/2022] Open
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Machaty Z. Signal transduction in mammalian oocytes during fertilization. Cell Tissue Res 2016; 363:169-183. [PMID: 26453398 PMCID: PMC4700098 DOI: 10.1007/s00441-015-2291-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 08/28/2015] [Indexed: 01/22/2023]
Abstract
Mammalian embryo development begins when the fertilizing sperm triggers a series of elevations in the oocyte's intracellular free Ca(2+) concentration. The elevations are the result of repeated release and re-uptake of Ca(2+) stored in the smooth endoplasmic reticulum. Ca(2+) release is primarily mediated by the phosphoinositide signaling system of the oocyte. The system is stimulated when the sperm causes the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG); IP3 then binds its receptor on the surface of the endoplasmic reticulum that induces Ca(2+) release. The manner in which the sperm generates IP3, the Ca(2+) mobilizing second messenger, has been the subject of extensive research for a long time. The sperm factor hypothesis has eventually gained general acceptance, according to which it is a molecule from the sperm that diffuses into the ooplasm and stimulates the phosphoinositide cascade. Much evidence now indicates that the sperm-derived factor is phospholipase C-zeta (PLCζ) that cleaves PIP2 and generates IP3, eventually leading to oocyte activation. A recent addition to the candidate sperm factor list is the post-acrosomal sheath WW domain-binding protein (PAWP), whose role at fertilization is currently under debate. Ca(2+) influx across the plasma membrane is also important as, in the absence of extracellular Ca(2+), the oscillations run down prematurely. In pig oocytes, the influx that sustains the oscillations seems to be regulated by the filling status of the stores, whereas in the mouse other mechanisms might be involved. This work summarizes the current understanding of Ca(2+) signaling in mammalian oocytes.
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Affiliation(s)
- Zoltan Machaty
- Department of Animal Sciences, Purdue University, 915 W. State Street, West Lafayette, IN, 47907, USA.
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Abstract
In mammalian species, including human, fertilization is characterized by the triggering of long-lasting calcium (Ca(2+)) oscillations in the egg cytoplasm. The monitoring of these Ca(2+) oscillations is a valuable technique to demonstrate that fertilization has occurred, to study egg activation events elicited downstream of the Ca(2+) signal, as well as to evaluate sperm quality. This chapter describes our protocol to monitor sperm-induced Ca(2+) oscillations in mouse eggs, using fluorescence microscopy techniques and the Fura-2-AM ratiometric Ca(2+) indicator.
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Affiliation(s)
- Guillaume Halet
- CNRS UMR6290, Institut de Génétique et Développement de Rennes, Université Rennes 1, 2 Avenue du Professeur LéonBernard, Rennes Cedex, 35043, France.
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Bernhardt ML, Zhang Y, Erxleben CF, Padilla-Banks E, McDonough CE, Miao YL, Armstrong DL, Williams CJ. CaV3.2 T-type channels mediate Ca²⁺ entry during oocyte maturation and following fertilization. J Cell Sci 2015; 128:4442-52. [PMID: 26483387 DOI: 10.1242/jcs.180026] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/12/2015] [Indexed: 01/05/2023] Open
Abstract
Initiation of mouse embryonic development depends upon a series of fertilization-induced rises in intracellular Ca(2+). Complete egg activation requires influx of extracellular Ca(2+); however, the channels that mediate this influx remain unknown. Here, we tested whether the α1 subunit of the T-type channel CaV3.2, encoded by Cacna1h, mediates Ca(2+) entry into oocytes. We show that mouse eggs express a robust voltage-activated Ca(2+) current that is completely absent in Cacna1h(-/-) eggs. Cacna1h(-/-) females have reduced litter sizes, and careful analysis of Ca(2+) oscillation patterns in Cacna1h(-/-) eggs following in vitro fertilization (IVF) revealed reductions in first transient length and oscillation persistence. Total and endoplasmic reticulum (ER) Ca(2+) stores were also reduced in Cacna1h(-/-) eggs. Pharmacological inhibition of CaV3.2 in wild-type CF-1 strain eggs using mibefradil or pimozide reduced Ca(2+) store accumulation during oocyte maturation and reduced Ca(2+) oscillation persistence, frequency and number following IVF. Overall, these data show that CaV3.2 T-type channels have prev8iously unrecognized roles in supporting the meiotic-maturation-associated increase in ER Ca(2+) stores and mediating Ca(2+) influx required for the activation of development.
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Affiliation(s)
- Miranda L Bernhardt
- Reproductive and Developmental Biology Laboratory, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Yingpei Zhang
- Reproductive and Developmental Biology Laboratory, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Christian F Erxleben
- Neurobiology Laboratory, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Elizabeth Padilla-Banks
- Reproductive and Developmental Biology Laboratory, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Caitlin E McDonough
- Reproductive and Developmental Biology Laboratory, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Yi-Liang Miao
- Key Laboratory of Animal Genetics, Breeding, and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - David L Armstrong
- Neurobiology Laboratory, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Carmen J Williams
- Reproductive and Developmental Biology Laboratory, National Institutes of Health, Research Triangle Park, NC 27709, USA
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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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45
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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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Bernhardt ML, Lowther KM, Padilla-Banks E, McDonough CE, Lee KN, Evsikov AV, Uliasz TF, Chidiac P, Williams CJ, Mehlmann LM. Regulator of G-protein signaling 2 (RGS2) suppresses premature calcium release in mouse eggs. Development 2015; 142:2633-40. [PMID: 26160904 DOI: 10.1242/dev.121707] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 06/25/2015] [Indexed: 11/20/2022]
Abstract
During oocyte maturation, capacity and sensitivity of Ca(2+) signaling machinery increases dramatically, preparing the metaphase II (MII)-arrested egg for fertilization. Upon sperm-egg fusion, Ca(2+) release from IP3-sensitive endoplasmic reticulum stores results in cytoplasmic Ca(2+) oscillations that drive egg activation and initiate early embryo development. Premature Ca(2+) release can cause parthenogenetic activation prior to fertilization; thus, preventing inappropriate Ca(2+) signaling is crucial for ensuring robust MII arrest. Here, we show that regulator of G-protein signaling 2 (RGS2) suppresses Ca(2+) release in MII eggs. Rgs2 mRNA was recruited for translation during oocyte maturation, resulting in ∼ 20-fold more RGS2 protein in MII eggs than in fully grown immature oocytes. Rgs2-siRNA-injected oocytes matured to MII; however, they had increased sensitivity to low pH and acetylcholine (ACh), which caused inappropriate Ca(2+) release and premature egg activation. When matured in vitro, RGS2-depleted eggs underwent spontaneous Ca(2+) increases that were sufficient to cause premature zona pellucida conversion. Rgs2(-/-) females had reduced litter sizes, and their eggs had increased sensitivity to low pH and ACh. Rgs2(-/-) eggs also underwent premature zona pellucida conversion in vivo. These findings indicate that RGS2 functions as a brake to suppress premature Ca(2+) release in eggs that are poised on the brink of development.
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Affiliation(s)
- Miranda L Bernhardt
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Katie M Lowther
- Department of Cell Biology, UConn Health, Farmington, CT 06030, USA
| | - Elizabeth Padilla-Banks
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Caitlin E McDonough
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Katherine N Lee
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A 5C1
| | - Alexei V Evsikov
- Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Tracy F Uliasz
- Department of Cell Biology, UConn Health, Farmington, CT 06030, USA
| | - Peter Chidiac
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A 5C1
| | - Carmen J Williams
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Lisa M Mehlmann
- Department of Cell Biology, UConn Health, Farmington, CT 06030, USA
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Yelumalai S, Yeste M, Jones C, Amdani SN, Kashir J, Mounce G, Da Silva SJM, Barratt CL, McVeigh E, Coward K. Total levels, localization patterns, and proportions of sperm exhibiting phospholipase C zeta are significantly correlated with fertilization rates after intracytoplasmic sperm injection. Fertil Steril 2015; 104:561-8.e4. [PMID: 26054556 DOI: 10.1016/j.fertnstert.2015.05.018] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 04/26/2015] [Accepted: 05/13/2015] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To study the relationship of total levels, localization patterns, and proportions of sperm exhibiting phospholipase C zeta, with fertilization rates after in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). DESIGN Laboratory study; controls vs. patients after IVF (n = 27) or ICSI (n = 17) treatment. SETTING Fertility center. PATIENT(S) A total of 44 semen samples, subjected to either IVF or ICSI treatment. Oocyte collection, ICSI or IVF, determination of sperm concentration and motility, and immunocytochemical analyses of phospholipase C zeta (PLCζ). INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Percentages of sperm exhibiting PLCζ. RESULT(S) Significant positive correlation between ICSI fertilization rates and total levels, localization patterns, and the proportion (percentage) of sperm exhibiting PLCζ. Total levels, localization patterns, and the proportion of sperm exhibiting PLCζ are correlated with fertilization rates for ICSI, but not for IVF. CONCLUSION(S) Evaluating total levels, localization patterns, and proportions of PLCζ may represent a useful diagnostic tool for clinical purposes in men for whom IVF is not advised or has previously failed. This clinical study further supports the fundamental role of PLCζ in the oocyte activation process.
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Affiliation(s)
- Suseela Yelumalai
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Headington, Oxford, United Kingdom
| | - Marc Yeste
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Headington, Oxford, United Kingdom
| | - Celine Jones
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Headington, Oxford, United Kingdom
| | - Siti N Amdani
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Headington, Oxford, United Kingdom
| | - Junaid Kashir
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Headington, Oxford, United Kingdom
| | - Ginny Mounce
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Headington, Oxford, United Kingdom
| | - Sarah J Martins Da Silva
- Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, Dundee, United Kingdom; Assisted Conception Unit, National Health Service Tayside, Ninewells Hospital, Dundee, United Kingdom
| | - Christopher L Barratt
- Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, Dundee, United Kingdom; Assisted Conception Unit, National Health Service Tayside, Ninewells Hospital, Dundee, United Kingdom
| | - Enda McVeigh
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Headington, Oxford, United Kingdom
| | - Kevin Coward
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Headington, Oxford, United Kingdom.
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Wang C, Zhang L, Jaeger LA, Machaty Z. Store-Operated Ca2+ Entry Sustains the Fertilization Ca2+ Signal in Pig Eggs. Biol Reprod 2015; 93:25. [PMID: 26063872 DOI: 10.1095/biolreprod.114.126151] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 06/01/2015] [Indexed: 11/01/2022] Open
Abstract
The role of store-operated Ca(2+) entry (SOCE) in the maintenance of sperm-induced Ca(2+) oscillations was investigated in porcine eggs. We found that 10 μM gadolinium (Gd(3+)), which is known to inhibit SOCE, blocked Ca(2+) entry that was triggered by thapsigargin-induced store depletion and also caused an abrupt cessation of the fertilization Ca(2+) signal. In a similar manner 3,5-bis(trifluoromethyl)pyrazole 2 (20 μM), and tetrapandin-2 (10 μM), potent SOCE inhibitors, also blocked thapsigargin-stimulated Ca(2+) entry and disrupted the Ca(2+) oscillations after sperm-egg fusion. The downregulation of Stim1 or Orai1 in the eggs did not alter the Ca(2+) content of the intracellular stores, whereas co-overexpression of these proteins led to the generation of irregular Ca(2+) transients after fertilization that stopped prematurely. We also found that thapsigargin completely emptied the endoplasmic reticulum, and that the series of Ca(2+) transients stopped abruptly after the addition of thapsigargin to the fertilized eggs, indicating that the proper reloading of the intracellular stores is a prerequisite for the maintenance of the Ca(2+) oscillations. These data strengthen our previous findings that in porcine eggs SOCE is a major signaling cascade that is responsible for sustaining the repetitive Ca(2+) signal at fertilization.
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Affiliation(s)
- Chunmin Wang
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana
| | - Lu Zhang
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana
| | - Laurie A Jaeger
- Department of Basic Medical Sciences, Purdue University, West Lafayette, Indiana
| | - Zoltan Machaty
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana
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Abstract
Egg activation is the first step of embryonic development and in mammals is triggered by a series of cytoplasmic calcium (Ca2+) oscillations. Sperm–egg fusion initiates these Ca2+ oscillations by introducing a sperm-specific protein factor into the egg cytoplasm. Substantial evidence indicates that this protein is a sperm-specific phospholipase C (PLC), termed PLC-zeta (PLCζ). PLCζ stimulates cytoplasmic Ca2+ oscillations matching those at fertilization triggering early embryonic development in several mammalian species. Structurally, PLCζ is comprised of four EF-hands, a C2 domain, and X and Y catalytic domains. PLCζ is an unusual PLC since it lacks a pleckstrin homology (PH) domain. It is also distinctive in that its X–Y linker is not involved in auto-inhibition of catalytic activity, but instead binds to phosphatidylinositol 4,5-bisphosphate (PIP2). Moreover, relative to other PLC isoforms, PLCζ possesses unique potency in stimulating Ca2+ oscillations in eggs, although it does not appear to bind to plasma membrane PIP2. In contrast, PLCζ appears to interact with intracellular vesicles in eggs that contain PIP2. I discuss the recent advances in our knowledge of the intriguing biochemical and physiological properties of sperm PLCζ and postulate potential roles for PLCζ in terms of clinical diagnosis and therapy for certain forms of male infertility.
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50
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Stith BJ. Phospholipase C and D regulation of Src, calcium release and membrane fusion during Xenopus laevis development. Dev Biol 2015; 401:188-205. [PMID: 25748412 DOI: 10.1016/j.ydbio.2015.02.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 02/15/2015] [Accepted: 02/24/2015] [Indexed: 11/28/2022]
Abstract
This review emphasizes how lipids regulate membrane fusion and the proteins involved in three developmental stages: oocyte maturation to the fertilizable egg, fertilization and during first cleavage. Decades of work show that phosphatidic acid (PA) releases intracellular calcium, and recent work shows that the lipid can activate Src tyrosine kinase or phospholipase C during Xenopus fertilization. Numerous reports are summarized to show three levels of increase in lipid second messengers inositol 1,4,5-trisphosphate and sn 1,2-diacylglycerol (DAG) during the three different developmental stages. In addition, possible roles for PA, ceramide, lysophosphatidylcholine, plasmalogens, phosphatidylinositol 4-phosphate, phosphatidylinositol 5-phosphate, phosphatidylinositol 4,5-bisphosphate, membrane microdomains (rafts) and phosphatidylinositol 3,4,5-trisphosphate in regulation of membrane fusion (acrosome reaction, sperm-egg fusion, cortical granule exocytosis), inositol 1,4,5-trisphosphate receptors, and calcium release are discussed. The role of six lipases involved in generating putative lipid second messengers during fertilization is also discussed: phospholipase D, autotaxin, lipin1, sphingomyelinase, phospholipase C, and phospholipase A2. More specifically, proteins involved in developmental events and their regulation through lipid binding to SH3, SH4, PH, PX, or C2 protein domains is emphasized. New models are presented for PA activation of Src (through SH3, SH4 and a unique domain), that this may be why the SH2 domain of PLCγ is not required for Xenopus fertilization, PA activation of phospholipase C, a role for PA during the calcium wave after fertilization, and that calcium/calmodulin may be responsible for the loss of Src from rafts after fertilization. Also discussed is that the large DAG increase during fertilization derives from phospholipase D production of PA and lipin dephosphorylation to DAG.
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Affiliation(s)
- Bradley J Stith
- University of Colorado Denver, Department of Integrative Biology, Campus Box 171, PO Box 173364, Denver, CO 80217-3364, United States.
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