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Suhaiman L, Belmonte SA. Lipid remodeling in acrosome exocytosis: unraveling key players in the human sperm. Front Cell Dev Biol 2024; 12:1457638. [PMID: 39376630 PMCID: PMC11456524 DOI: 10.3389/fcell.2024.1457638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2024] [Accepted: 09/03/2024] [Indexed: 10/09/2024] Open
Abstract
It has long been thought that exocytosis was driven exclusively by well-studied fusion proteins. Some decades ago, the role of lipids became evident and escalated interest in the field. Our laboratory chose a particular cell to face this issue: the human sperm. What makes this cell special? Sperm, as terminal cells, are characterized by their scarcity of organelles and the complete absence of transcriptional and translational activities. They are specialized for a singular membrane fusion occurrence: the exocytosis of the acrosome. This unique trait makes them invaluable for the study of exocytosis in isolation. We will discuss the lipids' role in human sperm acrosome exocytosis from various perspectives, with a primary emphasis on our contributions to the field. Sperm cells have a unique lipid composition, very rare and not observed in many cell types, comprising a high content of plasmalogens, long-chain, and very-long-chain polyunsaturated fatty acids that are particular constituents of some sphingolipids. This review endeavors to unravel the impact of membrane lipid composition on the proper functioning of the exocytic pathway in human sperm and how this lipid dynamic influences its fertilizing capability. Evidence from our and other laboratories allowed unveiling the role and importance of multiple lipids that drive exocytosis. This review highlights the role of cholesterol, diacylglycerol, and particular phospholipids like phosphatidic acid, phosphatidylinositol 4,5-bisphosphate, and sphingolipids in driving sperm acrosome exocytosis. Furthermore, we provide a comprehensive overview of the factors and enzymes that regulate lipid turnover during the exocytic course. A more thorough grasp of the role played by lipids transferred from sperm can provide insights into certain causes of male infertility. It may lead to enhancements in diagnosing infertility and techniques like assisted reproductive technology (ART).
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Affiliation(s)
- Laila Suhaiman
- Instituto de Medicina y Biología Experimental de Cuyo (IMBECU)-CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas), Argentina
- Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Silvia A. Belmonte
- Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
- Instituto de Histología y Embriología de Mendoza (IHEM) “Dr. Mario H. Burgos”, CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas), Universidad Nacional de Cuyo, Mendoza, Argentina
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2
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Cheng X, Xie H, Xiong Y, Sun P, Xue Y, Li K. Lipidomics profiles of human spermatozoa: insights into capacitation and acrosome reaction using UPLC-MS-based approach. Front Endocrinol (Lausanne) 2023; 14:1273878. [PMID: 38027124 PMCID: PMC10660817 DOI: 10.3389/fendo.2023.1273878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 10/10/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Lipidomics elucidates the roles of lipids in both physiological and pathological processes, intersecting with many diseases and cellular functions. The maintenance of lipid homeostasis, essential for cell health, significantly influences the survival, maturation, and functionality of sperm during fertilization. While capacitation and the acrosome reaction, key processes before fertilization, involve substantial lipidomic alterations, a comprehensive understanding of the changes in human spermatozoa's lipidomic profiles during these processes remains unknown. This study aims to explicate global lipidomic changes during capacitation and the acrosome reaction in human sperm, employing an untargeted lipidomic strategy using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Methods Twelve semen specimens, exceeding the WHO reference values for semen parameters, were collected. After discontinuous density gradient separation, sperm concentration was adjusted to 2 x 106 cells/ml and divided into three groups: uncapacitated, capacitated, and acrosome-reacted. UPLC-MS analysis was performed after lipid extraction from these groups. Spectral peak alignment and statistical analysis, using unsupervised principal component analysis (PCA), bidirectional orthogonal partial least squares discriminant analysis (O2PLS-DA) analysis, and supervised partial least-squares-latent structure discriminate analysis (PLS-DA), were employed to identify the most discriminative lipids. Results The 1176 lipid peaks overlapped across the twelve individuals in the uncapacitated, capacitated, and acrosome-reacted groups: 1180 peaks between the uncapacitated and capacitated groups, 1184 peaks between the uncapacitated and acrosome-reacted groups, and 1178 peaks between the capacitated and acrosome-reacted groups. The count of overlapping peaks varied among individuals, ranging from 739 to 963 across sperm samples. Moreover, 137 lipids had VIP values > 1.0 and twenty-two lipids had VIP > 1.5, based on the O2PLS-DA model. Furthermore, the identified twelve lipids encompassed increases in PI 44:10, LPS 20:4, LPA 20:5, and LPE 20:4, and decreases in 16-phenyl-tetranor-PGE2, PC 40:6, PS 35:4, PA 29:1, 20-carboxy-LTB4, and 2-oxo-4-methylthio-butanoic acid. Discussion This study has been the first time to investigate the lipidomics profiles associated with acrosome reaction and capacitation in human sperm, utilizing UPLC-MS in conjunction with multivariate data analysis. These findings corroborate earlier discoveries on lipids during the acrosome reaction and unveil new metabolites. Furthermore, this research highlights the effective utility of UPLC-MS-based lipidomics for exploring diverse physiological states in sperm. This study offers novel insights into lipidomic changes associated with capacitation and the acrosome reaction in human sperm, which are closely related to male reproduction.
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Affiliation(s)
- Xiaohong Cheng
- School of Pharmacy, Hangzhou Medical College, Hangzhou, China
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Haifeng Xie
- School of Pharmacy, Hangzhou Medical College, Hangzhou, China
| | - Yuping Xiong
- School of Pharmacy, Hangzhou Medical College, Hangzhou, China
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Peibei Sun
- School of Pharmacy, Hangzhou Medical College, Hangzhou, China
| | - Yamei Xue
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Kun Li
- School of Pharmacy, Hangzhou Medical College, Hangzhou, China
- Zhejiang Provincial Laboratory of Experimental Animal’s & Nonclinical Laboratory Studies, Hangzhou Medical College, Hangzhou, Zhejiang, China
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Wang M, Dubiak K, Zhang Z, Huber PW, Chen DDY, Dovichi NJ. MALDI-imaging of early stage Xenopus laevis embryos. Talanta 2019; 204:138-144. [PMID: 31357275 DOI: 10.1016/j.talanta.2019.05.060] [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] [Received: 04/08/2019] [Revised: 05/12/2019] [Accepted: 05/13/2019] [Indexed: 01/10/2023]
Abstract
Xenopus laevis is an important model organism for vertebrate development. An extensive literature has developed on changes in transcript expression during development of this organism, and there is a growing literature on the corresponding protein expression changes during development. In contrast, there is very little information on changes in metabolite expression during development. We present the first MALDI mass-spectrometry images of metabolites within the developing embryo. These images were generated for 142 metabolite ions. The images were subjected to an algorithm that revealed three spatially-resolved clusters of metabolites. One small cluster is localized near the outer membrane of the embryo. A large cluster of metabolites is found in cavities destined to form the neural tube and gut, and contains a number of ceramide species, which are associated with cellular signaling, including differentiation, proliferation, and programmed cell death. Another large cluster of metabolites is found in tissue and is dominated by phosphatidylcholines, which are common components of cell membranes. Surprisingly, no metabolites appear to be homogeneously distributed across the slices; metabolites are localized either within tissue or in cavities, but not both.
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Affiliation(s)
- Man Wang
- School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210023, China; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Kyle Dubiak
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Zhenbin Zhang
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Paul W Huber
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - David D Y Chen
- School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210023, China; Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Norman J Dovichi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA.
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Zarezadeh R, Mehdizadeh A, Leroy JLMR, Nouri M, Fayezi S, Darabi M. Action mechanisms of n-3 polyunsaturated fatty acids on the oocyte maturation and developmental competence: Potential advantages and disadvantages. J Cell Physiol 2018; 234:1016-1029. [PMID: 30073662 DOI: 10.1002/jcp.27101] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Accepted: 06/28/2018] [Indexed: 12/18/2022]
Abstract
Infertility is a growing problem worldwide. Currently, in vitro fertilization (IVF) is widely performed to treat infertility. However, a high percentage of IVF cycles fails, due to the poor developmental potential of the retrieved oocyte to generate viable embryos. Fatty acid content of the follicular microenvironment can affect oocyte maturation and the subsequent developmental competence. Saturated and monounsaturated fatty acids are mainly used by follicle components as primary energy sources whereas polyunsaturated fatty acids (PUFAs) play a wide range of roles. A large body of evidence supports the beneficial effects of n-3 PUFAs in prevention, treatment, and amelioration of some pathophysiological conditions including heart diseases, cancer, diabetes, and psychological disorders. Nevertheless, current findings regarding the effects of n-3 PUFAs on reproductive outcomes in general and on oocyte quality more specifically are inconsistent. This review attempts to provide a comprehensive overview of potential molecular mechanisms by which n-3 PUFAs affect oocyte maturation and developmental competence, particularly in the setting of IVF and thereby aims to elucidate the reasons behind current discrepancies around this topic.
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Affiliation(s)
- Reza Zarezadeh
- Women's Reproductive Health Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Biochemistry and Clinical Laboratories, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Amir Mehdizadeh
- Endocrine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Jo L M R Leroy
- Department of Veterinary Sciences, Gamete Research Center, Veterinary Physiology and Biochemistry, University of Antwerp, Wilrijk, Belgium
| | - Mohammad Nouri
- Stem Cell and Regenerative Medicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Shabnam Fayezi
- Infertility and Reproductive Health Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Université de Nice Sophia Antipolis, Inserm U1091 - CNRS U7277, Nice 06034, France
| | - Masoud Darabi
- Women's Reproductive Health Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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Akintunde J, Babaita A. Effect of PUFAs from Pteleopsis suberosa stem bark on androgenic enzymes, cellular ATP and prostatic acid phosphatase in mercury chloride – Exposed rat. MIDDLE EAST FERTILITY SOCIETY JOURNAL 2017. [DOI: 10.1016/j.mefs.2017.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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6
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Stauffer BB, Cui G, Cottrill KA, Infield DT, McCarty NA. Bacterial Sphingomyelinase is a State-Dependent Inhibitor of the Cystic Fibrosis Transmembrane conductance Regulator (CFTR). Sci Rep 2017; 7:2931. [PMID: 28592822 PMCID: PMC5462758 DOI: 10.1038/s41598-017-03103-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 04/24/2017] [Indexed: 02/07/2023] Open
Abstract
Sphingomyelinase C (SMase) inhibits CFTR chloride channel activity in multiple cell systems, an effect that could exacerbate disease in CF and COPD patients. The mechanism by which sphingomyelin catalysis inhibits CFTR is not known but evidence suggests that it occurs independently of CFTR's regulatory "R" domain. In this study we utilized the Xenopus oocyte expression system to shed light on how CFTR channel activity is reduced by SMase. We found that the pathway leading to inhibition is not membrane delimited and that inhibited CFTR channels remain at the cell membrane, indicative of a novel silencing mechanism. Consistent with an effect on CFTR gating behavior, we found that altering gating kinetics influenced the sensitivity to inhibition by SMase. Specifically, increasing channel activity by introducing the mutation K1250A or pretreating with the CFTR potentiator VX-770 (Ivacaftor) imparted resistance to inhibition. In primary bronchial epithelial cells, we found that basolateral, but not apical, application of SMase leads to a redistribution of sphingomyelin and a reduction in forskolin- and VX-770-stimulated currents. Taken together, these data suggest that SMase inhibits CFTR channel function by locking channels into a closed state and that endogenous CFTR in HBEs is affected by SMase activity.
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Affiliation(s)
- B B Stauffer
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory + Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA, 30322, USA
- Molecular and Systems Pharmacology program, Emory University, 201 Dowman Drive, Atlanta, GA, 20322, USA
| | - G Cui
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory + Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA, 30322, USA
| | - K A Cottrill
- Molecular and Systems Pharmacology program, Emory University, 201 Dowman Drive, Atlanta, GA, 20322, USA
| | - D T Infield
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory + Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA, 30322, USA
| | - N A McCarty
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory + Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA, 30322, USA.
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Belmonte SA, Mayorga LS, Tomes CN. The Molecules of Sperm Exocytosis. ADVANCES IN ANATOMY EMBRYOLOGY AND CELL BIOLOGY 2016; 220:71-92. [PMID: 27194350 DOI: 10.1007/978-3-319-30567-7_4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Exocytosis is a fundamental process used by eukaryotic cells to release biological compounds and to insert lipids and proteins in the plasma membrane. Specialized secretory cells undergo regulated exocytosis in response to physiological signals. Sperm exocytosis or acrosome reaction (AR) is essentially a regulated secretion with special characteristics. We will focus here on some of these unique features, covering the topology, kinetics, and molecular mechanisms that prepare, drive, and regulate membrane fusion during the AR. Last, we will compare acrosomal release with exocytosis in other model systems.
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Affiliation(s)
- Silvia A Belmonte
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología, IHEM-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, 5500, Mendoza, Mendoza, Argentina
| | - Luis S Mayorga
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología, IHEM-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, 5500, Mendoza, Mendoza, Argentina
| | - Claudia N Tomes
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología, IHEM-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, 5500, Mendoza, Mendoza, Argentina.
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8
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Bienias K, Fiedorowicz A, Sadowska A, Prokopiuk S, Car H. Regulation of sphingomyelin metabolism. Pharmacol Rep 2016; 68:570-81. [PMID: 26940196 DOI: 10.1016/j.pharep.2015.12.008] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 11/24/2015] [Accepted: 12/28/2015] [Indexed: 12/17/2022]
Abstract
Sphingolipids (SFs) represent a large class of lipids playing diverse functions in a vast number of physiological and pathological processes. Sphingomyelin (SM) is the most abundant SF in the cell, with ubiquitous distribution within mammalian tissues, and particularly high levels in the Central Nervous System (CNS). SM is an essential element of plasma membrane (PM) and its levels are crucial for the cell function. SM content in a cell is strictly regulated by the enzymes of SM metabolic pathways, which activities create a balance between SM synthesis and degradation. The de novo synthesis via SM synthases (SMSs) in the last step of the multi-stage process is the most important pathway of SM formation in a cell. The SM hydrolysis by sphingomyelinases (SMases) increases the concentration of ceramide (Cer), a bioactive molecule, which is involved in cellular proliferation, growth and apoptosis. By controlling the levels of SM and Cer, SMSs and SMases maintain cellular homeostasis. Enzymes of SM cycle exhibit unique properties and diverse tissue distribution. Disturbances in their activities were observed in many CNS pathologies. This review characterizes the physiological roles of SM and enzymes controlling SM levels as well as their involvement in selected pathologies of the Central Nervous System, such as ischemia/hypoxia, Alzheimer disease (AD), Parkinson disease (PD), depression, schizophrenia and Niemann Pick disease (NPD).
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Affiliation(s)
- Kamil Bienias
- Department of Experimental Pharmacology, Medical University of Białystok, Białystok, Poland
| | - Anna Fiedorowicz
- Department of Experimental Pharmacology, Medical University of Białystok, Białystok, Poland; Laboratory of Tumor Molecular Immunobiology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Anna Sadowska
- Department of Experimental Pharmacology, Medical University of Białystok, Białystok, Poland
| | - Sławomir Prokopiuk
- Department of Experimental Pharmacology, Medical University of Białystok, Białystok, Poland
| | - Halina Car
- Department of Experimental Pharmacology, Medical University of Białystok, Białystok, Poland.
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Participation of PLA2 and PLC in DhL-induced activation of Rhinella arenarum oocytes. ZYGOTE 2015; 24:495-501. [PMID: 26350822 DOI: 10.1017/s096719941500043x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Rhinella arenarum oocytes can be artificially activated, a process known as parthenogenesis, by a sesquiterpenic lactone of the guaianolide group, dehydroleucodine (DhL). Transient increases in the concentration of cytosolic Ca2+ are essential to trigger egg activation events. In this sense, the 1-4-5 inositol triphosphate receptors (IP3R) seem to be involved in the Ca2+ transient release induced by DhL in this species. We analyzed the involvement of phosphoinositide metabolism, especially the participation of phospholipase A2 (PLA2) and phospholipase C (PLC) in DhL-induced activation. Different doses of quinacrine, aristolochic acid (ATA) (PLA2 inhibitors) or neomycin, an antibiotic that binds to PIP2, thus preventing its hydrolysis, were used in mature Rhinella arenarum oocytes. In order to assay the participation of PI-PLC and PC- PLC we used U73122, a competitive inhibitor of PI-PLC dependent events and D609, an inhibitor of PC-PLC. We found that PLA2 inhibits quinacrine more effectively than ATA. This difference could be explained by the fact that quinacrine is not a specific inhibitor for PLA2 while ATA is specific for this enzyme. With respect to the participation of PLC, a higher decrease in oocyte activation was detected when cells were exposed to neomycin. Inhibition of PC-PLC with D609 and IP-PLC with U73122 indicated that the last PLC has a significant participation in the effect of DhL-induced activation. Results would indicate that DhL induces activation of in vitro matured oocytes of Rhinella arenarum by activation of IP-PLC, which in turn may induce IP3 formation which produces Ca2+ release.
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Hwang SY, Kim TH, Lee HH. Neutral sphingomyelinase and breast cancer research. J Menopausal Med 2015; 21:24-7. [PMID: 26046034 PMCID: PMC4452810 DOI: 10.6118/jmm.2015.21.1.24] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 03/24/2015] [Accepted: 04/01/2015] [Indexed: 01/09/2023] Open
Abstract
Our understanding of the functions of neutral sphingomyelinase (N-SMase) signaling has advanced over the past decade. In this review, we focus on the roles and regulation of N-SMase 1, N-SMase 2, N-SMase 3, an enzyme that generates the bioactive lipid ceramide through the hydrolysis of the membrane lipid sphingomyelin. A large body of work has now implicated N-SMase 2 in a diverse set of cellular functions, physiological processes, and disease pathologies. We focus on different aspects of this enzyme's regulation from transcriptional, post-translational, and biochemical. Furthermore, we expected N-SMase involvement in cellular processes including inflammatory signaling, cell growth, apoptosis, and tumor necrosis factor which in turn play important roles in pathologies such as cancer metastasis, variable disease, and other organ system disorders. Lastly, we examine avenues where targeted N-SMase inhibition may be clinically beneficial in disease scenarios.
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Affiliation(s)
- Sun-Yong Hwang
- Department of Interdisciplinary Program in Biomedical Science, Soonchunhyang University, Asan, Korea
| | - Tae-Hee Kim
- Department of Obstetrics and Gynecology, Soonchunhyang University, College of Medicine, Bucheon, Korea
| | - Hae-Hyeog Lee
- Department of Obstetrics and Gynecology, Soonchunhyang University, College of Medicine, Bucheon, Korea
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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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12
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Shrestha B, Sripadi P, Reschke BR, Henderson HD, Powell MJ, Moody SA, Vertes A. Subcellular metabolite and lipid analysis of Xenopus laevis eggs by LAESI mass spectrometry. PLoS One 2014; 9:e115173. [PMID: 25506922 PMCID: PMC4266676 DOI: 10.1371/journal.pone.0115173] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 11/19/2014] [Indexed: 01/04/2023] Open
Abstract
Xenopus laevis eggs are used as a biological model system for studying fertilization and early embryonic development in vertebrates. Most methods used for their molecular analysis require elaborate sample preparation including separate protocols for the water soluble and lipid components. In this study, laser ablation electrospray ionization (LAESI), an ambient ionization technique, was used for direct mass spectrometric analysis of X. laevis eggs and early stage embryos up to five cleavage cycles. Single unfertilized and fertilized eggs, their animal and vegetal poles, and embryos through the 32-cell stage were analyzed. Fifty two small metabolite ions, including glutathione, GABA and amino acids, as well as numerous lipids including 14 fatty acids, 13 lysophosphatidylcholines, 36 phosphatidylcholines and 29 triacylglycerols were putatively identified. Additionally, some proteins, for example thymosin β4 (Xen), were also detected. On the subcellular level, the lipid profiles were found to differ between the animal and vegetal poles of the eggs. Radial profiling revealed profound compositional differences between the jelly coat vitelline/plasma membrane and egg cytoplasm. Changes in the metabolic profile of the egg following fertilization, e.g., the decline of polyamine content with the development of the embryo were observed using LAESI-MS. This approach enables the exploration of metabolic and lipid changes during the early stages of embryogenesis.
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Affiliation(s)
- Bindesh Shrestha
- Department of Chemistry, W. M. Keck Institute for Proteomics Technology and Applications, The George Washington University, Washington, D.C., United States of America
| | - Prabhakar Sripadi
- Department of Chemistry, W. M. Keck Institute for Proteomics Technology and Applications, The George Washington University, Washington, D.C., United States of America
| | - Brent R. Reschke
- Protea Biosciences, Morgantown, West Virginia, United States of America
| | | | - Matthew J. Powell
- Protea Biosciences, Morgantown, West Virginia, United States of America
| | - Sally A. Moody
- Department of Anatomy and Regenerative Biology, The George Washington University, Washington, D.C., United States of America
| | - Akos Vertes
- Department of Chemistry, W. M. Keck Institute for Proteomics Technology and Applications, The George Washington University, Washington, D.C., United States of America
- * E-mail:
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Bothe I, Deng S, Baylies M. PI(4,5)P2 regulates myoblast fusion through Arp2/3 regulator localization at the fusion site. Development 2014; 141:2289-301. [PMID: 24821989 DOI: 10.1242/dev.100743] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Cell-cell fusion is a regulated process that requires merging of the opposing membranes and underlying cytoskeletons. However, the integration between membrane and cytoskeleton signaling during fusion is not known. Using Drosophila, we demonstrate that the membrane phosphoinositide PI(4,5)P2 is a crucial regulator of F-actin dynamics during myoblast fusion. PI(4,5)P2 is locally enriched and colocalizes spatially and temporally with the F-actin focus that defines the fusion site. PI(4,5)P2 enrichment depends on receptor engagement but is upstream or parallel to actin remodeling. Regulators of actin branching via Arp2/3 colocalize with PI(4,5)P2 in vivo and bind PI(4,5)P2 in vitro. Manipulation of PI(4,5)P2 availability leads to impaired fusion, with a reduction in the F-actin focus size and altered focus morphology. Mechanistically, the changes in the actin focus are due to a failure in the enrichment of actin regulators at the fusion site. Moreover, improper localization of these regulators hinders expansion of the fusion interface. Thus, PI(4,5)P2 enrichment at the fusion site encodes spatial and temporal information that regulates fusion progression through the localization of activators of actin polymerization.
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Affiliation(s)
- Ingo Bothe
- Program in Developmental Biology, Sloan Kettering Institute, New York, NY 10065, USA
| | - Su Deng
- Graduate Program in Physiology, Biophysics & Systems Biology, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, NY 10065, USA
| | - Mary Baylies
- Program in Developmental Biology, Sloan Kettering Institute, New York, NY 10065, USA Graduate Program in Physiology, Biophysics & Systems Biology, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, NY 10065, USA
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Fayezi S, Darabi M, Darabi M, Nouri M, Rahimipour A, Mehdizadeh A. Analysis of follicular fluid total phospholipids in women undergoingin-vitrofertilisation. J OBSTET GYNAECOL 2014; 34:259-62. [DOI: 10.3109/01443615.2013.851657] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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15
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Bates RC, Fees CP, Holland WL, Winger CC, Batbayar K, Ancar R, Bergren T, Petcoff D, Stith BJ. Activation of Src and release of intracellular calcium by phosphatidic acid during Xenopus laevis fertilization. Dev Biol 2013; 386:165-80. [PMID: 24269904 DOI: 10.1016/j.ydbio.2013.11.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 10/24/2013] [Accepted: 11/08/2013] [Indexed: 01/03/2023]
Abstract
We report a new step in the fertilization in Xenopus laevis which has been found to involve activation of Src tyrosine kinase to stimulate phospholipase C-γ (PLC-γ) which increases inositol 1,4,5-trisphosphate (IP3) to release intracellular calcium ([Ca](i)). Molecular species analysis and mass measurements suggested that sperm activate phospholipase D (PLD) to elevate phosphatidic acid (PA). We now report that PA mass increased 2.7 fold by 1 min after insemination and inhibition of PA production by two methods inhibited activation of Src and PLCγ, increased [Ca](i) and other fertilization events. As compared to 14 other lipids, PA specifically bound Xenopus Src but not PLCγ. Addition of synthetic PA activated egg Src (an action requiring intact lipid rafts) and PLCγ as well as doubling the amount of PLCγ in rafts. In the absence of elevated [Ca](i), PA addition elevated IP3 mass to levels equivalent to that induced by sperm (but twice that achieved by calcium ionophore). Finally, PA induced [Ca](i) release that was blocked by an IP3 receptor inhibitor. As only PLD1b message was detected, and Western blotting did not detect PLD2, we suggest that sperm activate PLD1b to elevate PA which then binds to and activates Src leading to PLCγ stimulation, IP3 elevation and [Ca](i) release. Due to these and other studies, PA may also play a role in membrane fusion events such as sperm-egg fusion, cortical granule exocytosis, the elevation of phosphatidylinositol 4,5-bisphosphate and the large, late increase in sn 1,2-diacylglycerol in fertilization.
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Key Words
- 1,2-dicapryloyl-sn-glycero-3-phosphate
- 1,2-dioctanoyl-sn-glycero-3-[phospho-l-serine]
- 5-fluoro-2-indolyl des-chlorohalopemide
- DAG
- ELSD
- Exocytosis
- FIPI
- IP3
- LPA
- LPC
- Membrane fusion
- Membrane rafts
- PA
- PC
- PE
- PI
- PI3
- PI345P3
- PI34P2
- PI35P2
- PI4
- PI45P2
- PI5
- PKC
- PLC
- PLCγ
- PLD
- PS
- Phospholipase Cγ
- Phospholipase D
- RT-PCR
- S1P
- [Ca](i)
- dPA
- dPS
- evaporative light scattering detector
- inositol 1,4,5-trisphosphate
- intracellular calcium
- lysophosphatidic acid
- lysophosphatidylcholine
- phosphatidic acid
- phosphatidylcholine
- phosphatidylethanolamine
- phosphatidylinositol
- phosphatidylinositol 3,4,5-trisphosphate
- phosphatidylinositol 3,4-bisphosphate
- phosphatidylinositol 3,5-bisphosphate
- phosphatidylinositol 3-phosphate
- phosphatidylinositol 4,5-bisphosphate
- phosphatidylinositol 4-phosphate
- phosphatidylinositol 5-phosphate
- phosphatidylserine
- phospholipase C
- phospholipase C-γ
- phospholipase D
- protein kinase C
- reverse transcriptase polymerase chain reaction
- sn 1,2-diacylglycerol
- sphingosine-1-phosphate
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Affiliation(s)
- Ryan C Bates
- University of Colorado Denver, Denver, CO 80217-3364, USA
| | - Colby P Fees
- University of Colorado Denver, Denver, CO 80217-3364, USA
| | | | | | | | - Rachel Ancar
- University of Colorado Denver, Denver, CO 80217-3364, USA
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Expression of phosphatidylcholine biosynthetic enzymes during early embryogenesis in the amphibian Bufo arenarum. ZYGOTE 2013; 23:257-65. [PMID: 24229731 DOI: 10.1017/s096719941300052x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In the principal route of phosphatidylcholine (PC) synthesis the regulatory steps are catalysed by CTP:phosphocholine cytidylyltransferase (CCT) and choline kinase (CK). Knock-out mice in Pcyt1a (CCT gene) and Chka1 (CK gene) resulted in preimplantation embryonic lethality, demonstrating the essential role of this pathway. However, there is still a lack of detailed CCT and CK expression analysis during development. The aim of the current work was to study the expression during early development of both enzymes in the external-fertilization vertebrate Bufo arenarum. Reverse transcription polymerase chain reaction (RT-PCR) and western blot confirmed their presence in unfertilized eggs. Analysis performed in total extracts from staged embryos showed constant protein levels of both enzymes until the 32-cell stage: then they decreased, reaching a minimum in the gastrula before starting to recover. CTP:phosphocholine cytidylyltransferase is an amphitropic enzyme that inter-converts between cytosolic inactive and membrane-bound active forms. Immunoblot analysis demonstrated that the cytosolic:total CCT protein ratio does not change throughout embryogenesis, suggesting a progressive decline of CCT activity in early development. However, PC (and phosphatidylethanolamine) content per egg/embryo remained constant throughout the stages analysed. In conclusion, the current data for B. arenarum suggest that net synthesis of PC mediated by CCT and CK is not required in early development and that supplies for membrane biosynthesis are fulfilled by lipids already present in the egg/embryo reservoirs.
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Identification of phospholipase activity in Rhinella arenarum sperm extract capable of inducing oocyte activation. ZYGOTE 2013; 22:483-95. [PMID: 24016596 DOI: 10.1017/s0967199413000348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Egg activation, which includes cortical granule exocytosis, resumption and completion of meiosis and pronuclear formation culminates in the first mitotic cleavage. However, the mechanism through which the fertilizing sperm induces this phenomenon is still controversial. We investigated the effect of the microinjection of homologous sperm soluble fractions obtained by fast protein liquid chromatography (FPLC) from reacted sperm (without acrosome) and non-reacted sperm on the activation of Rhinella arenarum oocytes matured in vitro. The FPLC-purified sperm fraction obtained from reacted or non-reacted sperm is able to induce oocyte activation when it is microinjected. This fraction has a 24 kDa protein and showed phospholipase C (PLC) activity in vitro, which was inhibited by D-609 but not by n-butanol or neomycin, suggesting that it is a PLC that is specific for phosphatidylcholine (PC-PLC). The assays conducted using inhibitors of inositol triphosphate (IP3) and ryanodine receptors (RyRs) indicate that the fraction with biological activity would act mainly through the cADPr (cyclic ADP ribose) pathway. Moreover, protein kinase C (PKC) inhibition blocks the activation produced by the same fraction. Immunocytochemical studies indicate that this PC-PLC can be found throughout the sperm head.
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Kashir J, Deguchi R, Jones C, Coward K, Stricker SA. Comparative biology of sperm factors and fertilization-induced calcium signals across the animal kingdom. Mol Reprod Dev 2013; 80:787-815. [PMID: 23900730 DOI: 10.1002/mrd.22222] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/23/2013] [Indexed: 11/08/2022]
Abstract
Fertilization causes mature oocytes or eggs to increase their concentrations of intracellular calcium ions (Ca²⁺) in all animals that have been examined, and such Ca²⁺ elevations, in turn, provide key activating signals that are required for non-parthenogenetic development. Several lines of evidence indicate that the Ca²⁺ transients produced during fertilization in mammals and other taxa are triggered by soluble factors that sperm deliver into oocytes after gamete fusion. Thus, for a broad-based analysis of Ca²⁺ dynamics during fertilization in animals, this article begins by summarizing data on soluble sperm factors in non-mammalian species, and subsequently reviews various topics related to a sperm-specific phospholipase C, called PLCζ, which is believed to be the predominant activator of mammalian oocytes. After characterizing initiation processes that involve sperm factors or alternative triggering mechanisms, the spatiotemporal patterns of Ca²⁺ signals in fertilized oocytes or eggs are compared in a taxon-by-taxon manner, and broadly classified as either a single major transient or a series of repetitive oscillations. Both solitary and oscillatory types of fertilization-induced Ca²⁺ signals are typically propagated as global waves that depend on Ca²⁺ release from the endoplasmic reticulum in response to increased concentrations of inositol 1,4,5-trisphosphate (IP₃). Thus, for taxa where relevant data are available, upstream pathways that elevate intraoocytic IP3 levels during fertilization are described, while other less-common modes of producing Ca²⁺ transients are also examined. In addition, the importance of fertilization-induced Ca²⁺ signals for activating development is underscored by noting some major downstream effects of these signals in various animals.
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Affiliation(s)
- Junaid Kashir
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, UK
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Rajasekharan A, Francis VG, Gummadi SN. Biochemical evidence for energy-independent flippase activity in bovine epididymal sperm membranes: an insight into membrane biogenesis. Reproduction 2013; 146:209-20. [PMID: 23801779 DOI: 10.1530/rep-13-0121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
During the maturation process spermatozoa undergo a series of changes in their lateral and horizontal lipid profiles. However, lipid metabolism in spermatozoa is not clearly understood for two reasons: i) the mature spermatozoa are devoid of endoplasmic reticulum, which is the major site of phospholipid (PL) synthesis in somatic cells, and ii) studies have been superficial due to the difficulty in culturing spermatozoa. We hypothesize that spermatozoa contain biogenic membrane flippases since immense changes in lipids occur during spermatogenic differentiation. To test this, we isolated spermatozoa from bovine epididymides and reconstituted the detergent extract of sperm membranes into proteoliposomes. In vitro assays showed that proteoliposomes reconstituted with sperm membrane proteins exhibit ATP-independent flip-flop movement of phosphatidylcholine (PC), phosphatidylserine, and phosphatidylglycerol. Half-life time of PC flipping was found to be ∼3.2±1 min for whole sperm membrane, which otherwise would have taken ∼11-12 h in the absence of protein. Further biochemical studies confirm the flip-flop movement to be protein-mediated, based on its sensitivity to protease and protein-modifying reagents. To further determine the cellular localization of flippases, we isolated mitochondria of spermatozoa and checked for ATP-independent flippase activity. Interestingly, mitochondrial membranes showed flip-flop movement but were specific for PC with half-life time of ∼5±2 min. Our results also suggest that spermatozoa have different populations of flippases and that their localization within the cellular compartments depends on the type of PL synthesis.
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Affiliation(s)
- Archita Rajasekharan
- Applied Industrial Microbiology Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai 600 036, India
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20
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Abstract
Sphingolipids are an important class of lipid molecules that play fundamental roles in our cells and body. Beyond a structural role, it is now clearly established that sphingolipids serve as bioactive signaling molecules to regulate diverse processes including inflammatory signaling, cell death, proliferation, and pain sensing. Sphingolipid metabolites have been implicated in the onset and progression of various diseases including cancer, lung disease, diabetes, and lysosomal storage disorders. Here we review sphingolipid metabolism to introduce basic concepts as well as emerging complexities in sphingolipid function gained from modern technological advances and detailed cell and animal studies. Furthermore, we discuss the family of neutral sphingomyelinases (N-SMases), which generate ceramide through the hydrolysis of sphingomyelin and are key enzymes in sphingolipid metabolism. Four mammalian N-SMase enzymes have now been identified. Most prominent is nSMase2 with established roles in bone mineralization, exosome formation, and cellular stress responses. Function for the other N-SMases has been more enigmatic and is an area of active investigation. The known properties and potential role(s) of each enzyme are discussed to help guide future studies.
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Maksaev G, Haswell ES. MscS-Like10 is a stretch-activated ion channel from Arabidopsis thaliana with a preference for anions. Proc Natl Acad Sci U S A 2012; 109:19015-20. [PMID: 23112188 PMCID: PMC3503204 DOI: 10.1073/pnas.1213931109] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Like many other organisms, plants are capable of sensing and responding to mechanical stimuli such as touch, osmotic pressure, and gravity. One mechanism for the perception of force is the activation of mechanosensitive (or stretch-activated) ion channels, and a number of mechanosensitive channel activities have been described in plant membranes. Based on their homology to the bacterial mechanosensitive channel MscS, the 10 MscS-Like (MSL) proteins of Arabidopsis thaliana have been hypothesized to form mechanosensitive channels in plant cell and organelle membranes. However, definitive proof that MSLs form mechanosensitive channels has been lacking. Here we used single-channel patch clamp electrophysiology to show that MSL10 is capable of providing a MS channel activity when heterologously expressed in Xenopus laevis oocytes. This channel had a conductance of ∼100 pS, consistent with the hypothesis that it underlies an activity previously observed in the plasma membrane of plant root cells. We found that MSL10 formed a channel with a moderate preference for anions, which was modulated by strongly positive and negative membrane potentials, and was reversibly inhibited by gadolinium, a known inhibitor of mechanosensitive channels. MSL10 demonstrated asymmetric activation/inactivation kinetics, with the channel closing at substantially lower tensions than channel opening. The electrophysiological characterization of MSL10 reported here provides insight into the evolution of structure and function of this important family of proteins.
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Affiliation(s)
- Grigory Maksaev
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130
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22
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Abstract
SummaryTransient increases in the concentration of cytosolic Ca2+ are essential for triggering egg activation events. Increased Ca2+ results from its rapid release from intracellular stores, mainly mediated by one or both intracellular calcium channels: the inositol trisphosphate receptor (IP3R) and the ryanodine receptor (RyR). Several regulatory pathways that tailor the response of these channels to the specific cell type have been proposed. Among its many modulatory actions, calcium can serve as an activator of a cytosolic phospholipase A2 (cPLA2), which releases arachidonic acid from phospholipids of the endoplasmic reticulum as well as from the nuclear envelope. Previous studies have suggested that arachidonic acid and/or its metabolites were able to modulate the activity of several ion channels. Based on these findings, we have studied the participation of the phospholipase A2 (PLA2) pathway in the process of Bufo arenarum oocyte activation and the interrelation between any of its metabolites and the ion channels involved in the calcium release from the intracellular reservoirs at fertilization. We found that addition of both melittin, a potent PLA2 activator, and arachidonic acid, the main PLA2 reaction metabolite, was able to induce activation events in a bell-shaped manner. Differential regulation of IP3Rs and RyRs by arachidonic acid and its products could explain melittin and arachidonic acid behaviour in Bufo arenarum egg activation. The concerted action of arachidonic acid and/or its metabolites could provide controlled mobilization of calcium from intracellular reservoirs and useful tools for understanding calcium homeostasis in eggs that express both types of receptors.
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Kalo D, Roth Z. Involvement of the sphingolipid ceramide in heat-shock-induced apoptosis of bovine oocytes. Reprod Fertil Dev 2011; 23:876-88. [DOI: 10.1071/rd10330] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2010] [Accepted: 03/30/2011] [Indexed: 01/29/2023] Open
Abstract
Programmed cell death via the sphingomyelin pathway has been suggested to underlie heat-shock disturbance of oocyte developmental competence. A series of experiments were performed to characterise the role of the sphingolipid ceramide in heat-shock-induced apoptosis, and to determine whether ceramide formation can be regulated. Bovine cumulus–oocyte complexes (COCs) were aspirated from ovaries collected in the cold season (November–April), in vitro-matured, fertilised and cultured for 8 days. Exposure of COCs to heat shock (41°C) during maturation reduced cleavage rate and blastocyst formation relative to the control group (38.5°C). Annexin-V binding (V-FITC assay), which is associated with the early apoptotic event of membrane phosphatidylserine turnover, was higher in oocytes exposed to short-term versus long-term heat shock, suggesting that heat-shock-induced apoptosis involves membrane alterations. Similar to heat exposure, oocyte maturation with C2-ceramide had a dose-dependent deleterious effect on the first cleavages and subsequent embryonic development in association with increased annexin-V binding. Blocking endogenous ceramide generation with fumonisin B1, a specific inhibitor of dihydroceramide synthase (i.e. de novo formation), moderated, to some extent, the effects of heat shock on oocyte developmental competence, suggesting that ceramide plays an important role in heat-shock-induced apoptosis.
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Schenk S, Gras H, Marksteiner D, Patasic L, Prommnitz B, Hoeger U. The Pandinus imperator haemolymph lipoprotein, an unusual phosphatidylserine carrying lipoprotein. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2009; 39:735-744. [PMID: 19729064 DOI: 10.1016/j.ibmb.2009.08.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 08/17/2009] [Accepted: 08/26/2009] [Indexed: 05/28/2023]
Abstract
The haemolymph lipoprotein of the scorpion, Pandinus imperator was isolated and characterised. Contrary to the lipoproteins of insects and the discoidal HDL-lipoproteins of a crayfish and polychaete, the Pandinus lipoprotein consists of three instead of two apoproteins (apoPiLp I = 230 kDa, apoPiLp II = 130 kDa and apoPiLp III = 120 kDa). The apolipoproteins are arranged in varying stoichiometries as judged by cross-linking experiments. In lipoprotein samples from individual animals, the two smaller subunits occurred in a 1:1 stoichiometry, while the relative amount of the 230 kDa peptide varied. The lipoprotein is a slightly heart-shaped HDL with a diameter of approximately 15 nm. It is present in two densities of 1100 and 1190 kg/m(3), of which the latter is by far more abundant. The native molecular mass was estimated to be approximately 500 kDa. The lipid content was determined as 33.5% and consists of approximately 70% neutral lipids and approximately 30% phospholipids. Strikingly, 42.5% of the phospholipids is phosphatidylserine while phosphatidylcholine and phosphatidylethanolamine account for 55.1% and approximately 2.3%, respectively. Carbohydrate analysis suggests the presence of only high-mannose-type N-glycans. N-glycan profiling shows glycans corresponding to a size of 8.0-11.5 hexose units.
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Affiliation(s)
- Sven Schenk
- Institut für Zoologie, Johannes Gutenberg-Universität Mainz, Johannes von Müller-Weg 6, Mainz, Germany.
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