1
|
Alavi SMH, Barzegar-Fallah S, Yoshida M, Butts IAE, Osada M. Serotonin-Induced Sperm Hyper-Motility In Pacific Oyster (Crassostrea Gigas) Associates With K + Efflux and Membrane Hyperpolarization. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2025. [PMID: 40200823 DOI: 10.1002/jez.2918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Revised: 02/21/2025] [Accepted: 03/10/2025] [Indexed: 04/10/2025]
Abstract
Serotonin (5-HT) induces sperm hyper-motility in bivalves. This process has been suggested to be associated with K+ efflux due to higher concentrations of K+ ions in testicular fluid compared to that of seawater. This hypothesis was supported by inhibition of 5-HT-induced sperm hyper-motility in artificial seawater (ASW) containing high extracellular K+ ions or in the presence of a voltage-dependent K+ channel blocker (4-AP). Here, we studied changes of sperm membrane potential to elucidate 5-HT-induced sperm hyper-motility signaling in Pacific oyster (Crassostrea gigas). Sperm motility was partially initiated (48.34 ± 7.80%) in ASW, and decreased at 5 min post-activation (p < 0.05). In the presence of 10-5 M 5-HT, sperm motility was recorded 81.63 ± 3.55%, which remained unchanged within 60 min post-activation. After sperm activation in ASW with or without 5-HT, fluorescence intensity of membrane potential-sensitive fluorescent (DiSC3(5)) was decreased to lower than that of the resting stage, indicating membrane hyperpolarization. Induction of membrane hyperpolarization, using valinomycin or in K+-free ASW (KF-ASW) could not trigger sperm hyper-motility, suggesting that hyperpolarization itself did not induce sperm hyper-motility. Next, we showed that membrane hyperpolarization was due to K+ efflux. The fluorescence intensity of DiSC3(5) was increased in ASW or KF-ASW containing 4-AP, suggesting membrane depolarization due to inhibition of K+ efflux. The valinomycin-induced membrane hyperpolarization was changed to depolarization by subsequent additions of KCl, suggesting that changes in the electrochemical gradient of K+ ions resulted in the retention of intracellular K+ ions. Observed membrane depolarization in the presence of 4-AP or high K+ ions was associated with inhibition of 5-HT-induced sperm hyper-motility. Taken together, this study shows that 5-HT-induced sperm hyper-motility was associated with membrane hyperpolarization due to K+ efflux.
Collapse
Affiliation(s)
- Sayyed Mohammad Hadi Alavi
- Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, Japan
- School of Biology, College of Science, University of Tehran, Tehran, Tehran, Iran
| | - Sepideh Barzegar-Fallah
- School of Biology, College of Science, University of Tehran, Tehran, Tehran, Iran
- School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, Alabama, USA
| | - Manabu Yoshida
- Misaki Marine Biological Station, School of Science, University of Tokyo, Miura, Kanagawa, Japan
| | - Ian A E Butts
- School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, Alabama, USA
| | - Makoto Osada
- Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, Japan
- Graduate School of Environmental Studies, Tohoku University, Sendai, Miyagi, Japan
| |
Collapse
|
2
|
Priego Espinosa D, Espinal-Enríquez J, Aldana A, Aldana M, Martínez-Mekler G, Carneiro J, Darszon A. Reviewing mathematical models of sperm signaling networks. Mol Reprod Dev 2024; 91:e23766. [PMID: 39175359 DOI: 10.1002/mrd.23766] [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: 05/17/2024] [Accepted: 07/22/2024] [Indexed: 08/24/2024]
Abstract
Dave Garbers' work significantly contributed to our understanding of sperm's regulated motility, capacitation, and the acrosome reaction. These key sperm functions involve complex multistep signaling pathways engaging numerous finely orchestrated elements. Despite significant progress, many parameters and interactions among these elements remain elusive. Mathematical modeling emerges as a potent tool to study sperm physiology, providing a framework to integrate experimental results and capture functional dynamics considering biochemical, biophysical, and cellular elements. Depending on research objectives, different modeling strategies, broadly categorized into continuous and discrete approaches, reveal valuable insights into cell function. These models allow the exploration of hypotheses regarding molecules, conditions, and pathways, whenever they become challenging to evaluate experimentally. This review presents an overview of current theoretical and experimental efforts to understand sperm motility regulation, capacitation, and the acrosome reaction. We discuss the strengths and weaknesses of different modeling strategies and highlight key findings and unresolved questions. Notable discoveries include the importance of specific ion channels, the role of intracellular molecular heterogeneity in capacitation and the acrosome reaction, and the impact of pH changes on acrosomal exocytosis. Ultimately, this review underscores the crucial importance of mathematical frameworks in advancing our understanding of sperm physiology and guiding future experimental investigations.
Collapse
Affiliation(s)
| | - Jesús Espinal-Enríquez
- Computational Genomics Division, National Institute of Genomic Medicine (INMEGEN), Mexico City, Mexico
| | - Andrés Aldana
- Network Science Institute, Northeastern University, Boston, Massachusetts, USA
| | - Maximino Aldana
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México (UNAM), Mexico City, México
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Gustavo Martínez-Mekler
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México (UNAM), Mexico City, México
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Jorge Carneiro
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Alberto Darszon
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México
| |
Collapse
|
3
|
Mata-Martínez E, Sánchez-Cárdenas C, Chávez JC, Guerrero A, Treviño CL, Corkidi G, Montoya F, Hernandez-Herrera P, Buffone MG, Balestrini PA, Darszon A. Role of calcium oscillations in sperm physiology. Biosystems 2021; 209:104524. [PMID: 34453988 DOI: 10.1016/j.biosystems.2021.104524] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/23/2021] [Accepted: 08/24/2021] [Indexed: 10/20/2022]
Abstract
Intracellular Ca2+ is a key regulator of cell signaling and sperm are not the exception. Cells often use cytoplasmic Ca2+ concentration ([Ca2+]i) oscillations as a means to decodify external and internal information. [Ca2+]i oscillations faster than those usually found in other cells and correlated with flagellar beat were the first to be described in sperm in 1993 by Susan Suarez, in the boar. More than 20 years passed before similar [Ca2+]i oscillations were documented in human sperm, simultaneously examining their flagellar beat in three dimensions by Corkidi et al. 2017. On the other hand, 10 years after the discovery of the fast boar [Ca2+]i oscillations, slower ones triggered by compounds from the egg external envelope were found to regulate cell motility and chemotaxis in sperm from marine organisms. Today it is known that sperm display fast and slow spontaneous and agonist triggered [Ca2+]i oscillations. In mammalian sperm these Ca2+ transients may act like a multifaceted tool that regulates fundamental functions such as motility and acrosome reaction. This review covers the main sperm species and experimental conditions where [Ca2+]i oscillations have been described and discusses what is known about the transporters involved, their regulation and the physiological purpose of these oscillations. There is a lot to be learned regarding the origin, regulation and physiological relevance of these Ca2+ oscillations.
Collapse
Affiliation(s)
- Esperanza Mata-Martínez
- Laboratorio de Fusión de Membranas y Exocitosis Acrosomal, Instituto de Histología y Embriología Dr. Mario H. Burgos (IHEM) Universidad Nacional de Cuyo, CONICET, Mendoza, Argentina.
| | - Claudia Sánchez-Cárdenas
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología (IBT), Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico.
| | - Julio C Chávez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología (IBT), Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico.
| | - Adán Guerrero
- Laboratorio Nacional de Microscopía Avanzada, IBT, UNAM, Mexico.
| | - Claudia L Treviño
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología (IBT), Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico.
| | - Gabriel Corkidi
- Departamento de Ingeniería Celular y Biocatálisis, Laboratorio de Imágenes y Visión por Computadora, IBT, UNAM, Mexico.
| | - Fernando Montoya
- Departamento de Ingeniería Celular y Biocatálisis, Laboratorio de Imágenes y Visión por Computadora, IBT, UNAM, Mexico.
| | - Paul Hernandez-Herrera
- Departamento de Ingeniería Celular y Biocatálisis, Laboratorio de Imágenes y Visión por Computadora, IBT, UNAM, Mexico.
| | - Mariano G Buffone
- Instituto de Biología y Medicina Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
| | - Paula A Balestrini
- Instituto de Biología y Medicina Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
| | - Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología (IBT), Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico.
| |
Collapse
|
4
|
Kato D, Shiraishi T, Kagechika H, Hirano T. 6-Arylcoumarin as a Scaffold of Photofunctional Molecules with OFF-ON-OFF Type Regulation. J Org Chem 2021; 86:2264-2270. [PMID: 33356259 DOI: 10.1021/acs.joc.0c02419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Coumarin has been utilized as a core structure of photofunctional molecules, such as fluorescent sensors and photoremovable protecting groups. Here, we show that the 6-arylcoumarin moiety can provide OFF-ON-OFF type regulatory functionality for such compounds. To illustrate its utility, we synthesized a coumarin derivative bearing two phenolic hydroxy groups at 7-position and on 6-aryl group as a fluorescent sensor showing an OFF-ON-OFF change in fluorescence intensity in response to an increase in pH from a strongly acidic condition. Further, we show that the efficiency of photoreaction of other derivatives with the same hydroxyl groups is switched from "OFF" at pH 3 and 6 to "ON" at pH 9 and then to OFF at pH 12, enabling their application as switchable photoremovable protective groups. These features arise from sequential deprotonation of two hydroxyl groups: the monoanionic form is responsible for the photoinduced fluorescence and photoreaction.
Collapse
Affiliation(s)
- Daiki Kato
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan
| | - Takuya Shiraishi
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan
| | - Hiroyuki Kagechika
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan
| | - Tomoya Hirano
- Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan
| |
Collapse
|
5
|
Roldan ERS, Teves ME. Understanding sperm physiology: Proximate and evolutionary explanations of sperm diversity. Mol Cell Endocrinol 2020; 518:110980. [PMID: 32853744 DOI: 10.1016/j.mce.2020.110980] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/19/2022]
Abstract
Much can be gained from the comprehensive study of a biological system. Based on what is known as Mayr's proximate-ultimate causation and the subsequent expansion to Tinbergen's four questions, biological traits can be understood by taking into account different approximations that try to explain mechanisms, development, adaptive significance or phylogeny. These, in principle, separate areas, can be integrated crossing boundaries, but bearing in mind that answers to one question would not explain a different query. Studies of sperm biology have, until now, not benefited much from this framework and potential integration. Proximate causes (particularly mechanisms) have been the subject of interest for reproductive biologists, and evolutionary explanations have been the domain of behavioural ecologists with interest in adaptive significance of traits in the context of post-copulatory sexual selection. This review will summarize opportunities for research in the different areas, focusing on sperm preparation for fertilization and suggesting possible integration within and between proximate and evolutionary studies.
Collapse
Affiliation(s)
- Eduardo R S Roldan
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain.
| | - Maria Eugenia Teves
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, VA, USA.
| |
Collapse
|
6
|
Darszon A, Nishigaki T, López-González I, Visconti PE, Treviño CL. Differences and Similarities: The Richness of Comparative Sperm Physiology. Physiology (Bethesda) 2020; 35:196-208. [PMID: 32293232 PMCID: PMC11960811 DOI: 10.1152/physiol.00033.2019] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 01/09/2020] [Accepted: 01/09/2020] [Indexed: 12/18/2022] Open
Abstract
Species preservation depends on the success of fertilization. Sperm are uniquely equipped to fulfill this task, and, although several mechanisms are conserved among species, striking functional differences have evolved to contend with particular sperm-egg environmental characteristics. This review highlights similarities and differences in sperm strategies, with examples within internal and external fertilizers, pointing out unresolved issues.
Collapse
Affiliation(s)
- Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca Morelos, México
| | - Takuya Nishigaki
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca Morelos, México
| | - Ignacio López-González
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca Morelos, México
| | - Pablo E Visconti
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts
| | - Claudia L Treviño
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca Morelos, México
| |
Collapse
|
7
|
Ramírez-Gómez HV, Jimenez Sabinina V, Velázquez Pérez M, Beltran C, Carneiro J, Wood CD, Tuval I, Darszon A, Guerrero A. Sperm chemotaxis is driven by the slope of the chemoattractant concentration field. eLife 2020; 9:50532. [PMID: 32149603 PMCID: PMC7093112 DOI: 10.7554/elife.50532] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 03/06/2020] [Indexed: 01/24/2023] Open
Abstract
Spermatozoa of marine invertebrates are attracted to their conspecific female gamete by diffusive molecules, called chemoattractants, released from the egg investments in a process known as chemotaxis. The information from the egg chemoattractant concentration field is decoded into intracellular Ca2+ concentration ([Ca2+]i) changes that regulate the internal motors that shape the flagellum as it beats. By studying sea urchin species-specific differences in sperm chemoattractant-receptor characteristics we show that receptor density constrains the steepness of the chemoattractant concentration gradient detectable by spermatozoa. Through analyzing different chemoattractant gradient forms, we demonstrate for the first time that Strongylocentrotus purpuratus sperm are chemotactic and this response is consistent with frequency entrainment of two coupled physiological oscillators: i) the stimulus function and ii) the [Ca2+]i changes. We demonstrate that the slope of the chemoattractant gradients provides the coupling force between both oscillators, arising as a fundamental requirement for sperm chemotaxis.
Collapse
Affiliation(s)
- Héctor Vicente Ramírez-Gómez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Vilma Jimenez Sabinina
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Martín Velázquez Pérez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Carmen Beltran
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Jorge Carneiro
- Instituto Gulbenkian de Ciência (IGC), Rua da Quinta Grande, Oeiras, Portugal
| | - Christopher D Wood
- Laboratorio Nacional de Microscopía Avanzada, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Idan Tuval
- Mediterranean Institute for Advanced Studies, IMEDEA (CSIC-UIB), Esporles, Spain.,Department of Physics, University of the Balearic Islands, Palma, Spain
| | - Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Adán Guerrero
- Laboratorio Nacional de Microscopía Avanzada, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| |
Collapse
|
8
|
Priego-Espinosa DA, Darszon A, Guerrero A, González-Cota AL, Nishigaki T, Martínez-Mekler G, Carneiro J. Modular analysis of the control of flagellar Ca2+-spike trains produced by CatSper and CaV channels in sea urchin sperm. PLoS Comput Biol 2020; 16:e1007605. [PMID: 32119665 PMCID: PMC7067495 DOI: 10.1371/journal.pcbi.1007605] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/12/2020] [Accepted: 12/13/2019] [Indexed: 11/18/2022] Open
Abstract
Intracellular calcium ([Ca2+]i) is a basic and ubiquitous cellular signal controlling a wide variety of biological processes. A remarkable example is the steering of sea urchin spermatozoa towards the conspecific egg by a spatially and temporally orchestrated series of [Ca2+]i spikes. Although this process has been an experimental paradigm for reproduction and sperm chemotaxis studies, the composition and regulation of the signalling network underlying the cytosolic calcium fluctuations are hitherto not fully understood. Here, we used a differential equations model of the signalling network to assess which set of channels can explain the characteristic envelope and temporal organisation of the [Ca2+]i-spike trains. The signalling network comprises an initial membrane hyperpolarisation produced by an Upstream module triggered by the egg-released chemoattractant peptide, via receptor activation, cGMP synthesis and decay. Followed by downstream modules leading to intraflagellar pH (pHi), voltage and [Ca2+]i fluctuations. The Upstream module outputs were fitted to kinetic data on cGMP activity and early membrane potential changes measured in bulk cell populations. Two candidate modules featuring voltage-dependent Ca2+-channels link these outputs to the downstream dynamics and can independently explain the typical decaying envelope and the progressive spacing of the spikes. In the first module, [Ca2+]i-spike trains require the concerted action of a classical CaV-like channel and a potassium channel, BK (Slo1), whereas the second module relies on pHi-dependent CatSper dynamics articulated with voltage-dependent neutral sodium-proton exchanger (NHE). We analysed the dynamics of these two modules alone and in mixed scenarios. We show that the [Ca2+]i dynamics observed experimentally after sustained alkalinisation can be reproduced by a model featuring the CatSper and NHE module but not by those including the pH-independent CaV and BK module or proportionate mixed scenarios. We conclude in favour of the module containing CatSper and NHE and highlight experimentally testable predictions that would corroborate this conclusion. Fertilisation in marine invertebrates, such as the sea urchin, occurs during broadcast spawning events in which males and females of co-localised species ejaculate sperm and spawn eggs synchronously. During these events, spermatozoa have to find and fertilise conspecific eggs in the midst of all the other ones, which is a remarkable navigation and mating choice achievement. Sperm cells do this by navigating towards the source of species-specific peptides released by the egg, steered by spatial and temporally orchestrated peaks in intracellular calcium concentration that trigger sudden reorientations. How these calcium spikes are regulated and timed remains elusive. Different calcium channels have been implicated by indirect experimental evidence giving rise to a complex network of putative interacting components. We gained insight into the structure and function of this network by modelling it as a set of candidate modules that could be studied separately. By using this ‘divide and conquer’ approach to the complexity of the network, we could characterise the potential dynamics of each module and confront these dynamics with specific quantitative data. Our results indicate that the channel mediating calcium signals in sea urchin sperm is likely CatSper, a calcium channel necessary for human male fertility.
Collapse
Affiliation(s)
| | - Alberto Darszon
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Adán Guerrero
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Ana Laura González-Cota
- Washington University School of Medicine, Department of Obstetrics and Gynecology, Center for Reproductive Health Sciences, St. Louis, Missouri, United States of America
| | - Takuya Nishigaki
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Gustavo Martínez-Mekler
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- Centro de Ciencias de la Complejidad UNAM, CDMX, México
- Laboratoire de Physique Statistique, Départment de Physique, Ecole Normale Supérieure, Paris, France
- * E-mail: (GMM); (JC)
| | - Jorge Carneiro
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- * E-mail: (GMM); (JC)
| |
Collapse
|
9
|
Kinoshita-Terauchi N, Shiba K, Terauchi M, Romero F, Ramírez-Gómez HV, Yoshida M, Motomura T, Kawai H, Nishigaki T. High potassium seawater inhibits ascidian sperm chemotaxis, but does not affect the male gamete chemotaxis of a brown alga. ZYGOTE 2019; 27:225-231. [PMID: 31317854 DOI: 10.1017/s0967199419000224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Male gamete chemotaxis towards the female gamete is a general strategy to facilitate the sexual reproduction in many marine eukaryotes. Biochemical studies of chemoattractants for male gametes of brown algae have advanced in the 1970s and 1980s, but the molecular mechanism of male gamete responses to the attractants remains elusive. In sea urchin, a K+ channel called the tetraKCNG channel plays a fundamental role in sperm chemotaxis and inhibition of K+ efflux through this channel by high K+ seawater blocks almost all cell responses to the chemoattractant. This signalling mechanism could be conserved in marine invertebrates as tetraKCNG channels are conserved in the marine invertebrates that exhibit sperm chemotaxis. We confirmed that high K+ seawater also inhibited sperm chemotaxis in ascidian, Ciona intestinalis (robusta), in this study. Conversely, the male gamete chemotaxis towards the female gamete of a brown alga, Mutimo cylindricus, was preserved even in high K+ seawater. This result indicates that none of the K+ channels is essential for male gamete chemotaxis in the brown alga, suggesting that the signalling mechanism for chemotaxis in this brown alga is quite different from that of marine invertebrates. Correlated to this result, we revealed that the channels previously proposed as homologues of tetraKCNG in brown algae have a distinct domain composition from that of the tetraKCNG. Namely, one of them possesses two repeats of the six transmembrane segments (diKCNG) instead of four. The structural analysis suggests that diKCNG is a cyclic nucleotide-modulated and/or voltage-gated K+ channel.
Collapse
Affiliation(s)
- Nana Kinoshita-Terauchi
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda City, Shizuoka 415-0025, Japan
| | - Kogiku Shiba
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda City, Shizuoka 415-0025, Japan
- Misaki Marine Biological Station, Graduate School of Science, University of Tokyo, Miura, Kanagawa 238-0225, Japan
| | - Makoto Terauchi
- Kobe University Research Center for Inland Seas, Rokkodai, Kobe 657-8501, Japan
- Center for Genome Informatics, Joint Support-Center for Data Science Research, Research Organization of Information and Systems, Mishima, Shizuoka 411-8540, Japan
| | - Francisco Romero
- Institute of Biotechnology, National Autonomous University of Mexico (IBT-UNAM), Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Mor. 62210, Mexico
| | - Héctor Vincente Ramírez-Gómez
- Institute of Biotechnology, National Autonomous University of Mexico (IBT-UNAM), Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Mor. 62210, Mexico
| | - Manabu Yoshida
- Misaki Marine Biological Station, Graduate School of Science, University of Tokyo, Miura, Kanagawa 238-0225, Japan
| | - Taizo Motomura
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran 051-0013, Hokkaido, Japan
| | - Hiroshi Kawai
- Kobe University Research Center for Inland Seas, Rokkodai, Kobe 657-8501, Japan
| | - Takuya Nishigaki
- Institute of Biotechnology, National Autonomous University of Mexico (IBT-UNAM), Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Mor. 62210, Mexico
| |
Collapse
|
10
|
Romero F, Nishigaki T. Comparative genomic analysis suggests that the sperm-specific sodium/proton exchanger and soluble adenylyl cyclase are key regulators of CatSper among the Metazoa. ZOOLOGICAL LETTERS 2019; 5:25. [PMID: 31372239 PMCID: PMC6660944 DOI: 10.1186/s40851-019-0141-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 07/08/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND CatSper is a sperm-specific calcium ion (Ca2+) channel, which regulates sperm flagellar beating by tuning cytoplasmic Ca2+ concentrations. Although this Ca2+ channel is essential for mammalian fertilization, recent bioinformatics analyses have revealed that genes encoding CatSper are heterogeneously distributed throughout the eukaryotes, including vertebrates. As this channel is activated by cytoplasmic alkalization in mammals and sea urchins, it has been proposed that the sperm-specific Na+/H+ exchanger (sNHE, a product of the SLC9C gene family) positively regulates its activity. In mouse, sNHE is functionally coupled to soluble adenylyl cyclase (sAC). CatSper, sNHE, and sAC have thus been considered functionally interconnected in the control of sperm motility, at least in mouse and sea urchin. RESULTS We carried out a comparative genomic analysis to explore phylogenetic relationships among CatSper, sNHE and sAC in eukaryotes. We found that sNHE occurs only in Metazoa, although sAC occurs widely across eukaryotes. In animals, we found correlated and restricted distribution patterns of the three proteins, suggesting coevolution among them in the Metazoa. Namely, nearly all species in which CatSper is conserved also preserve sNHE and sAC. In contrast, in species without sAC, neither CatSper nor sNHE is conserved. On the other hand, the distribution of another testis-specific NHE (NHA, a product of the SLC9B gene family) does not show any apparent association with that of CatSper. CONCLUSIONS Our results suggest that CatSper, sNHE and sAC form prototypical machinery that functions in regulating sperm flagellar beating in Metazoa. In non-metazoan species, CatSper may be regulated by other H+ transporters, or its activity might be independent of cytoplasmic pH.
Collapse
Affiliation(s)
- Francisco Romero
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología. Universidad Nacional Autónoma de México (IBT-UNAM). Av. Universidad 2001, Col. Chamilpa, 62210 Cuernavaca, Morelos Mexico
| | - Takuya Nishigaki
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología. Universidad Nacional Autónoma de México (IBT-UNAM). Av. Universidad 2001, Col. Chamilpa, 62210 Cuernavaca, Morelos Mexico
| |
Collapse
|
11
|
Yoshida K, Shiba K, Sakamoto A, Ikenaga J, Matsunaga S, Inaba K, Yoshida M. Ca 2+ efflux via plasma membrane Ca 2+-ATPase mediates chemotaxis in ascidian sperm. Sci Rep 2018; 8:16622. [PMID: 30413746 PMCID: PMC6226504 DOI: 10.1038/s41598-018-35013-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 10/30/2018] [Indexed: 12/15/2022] Open
Abstract
When a spermatozoon shows chemotactic behavior, transient [Ca2+]i increases in the spermatozoon are induced by an attractant gradient. The [Ca2+]i increase triggers a series of stereotypic responses of flagellar waveforms that comprise turning and straight-swimming. However, the molecular mechanism of [Ca2+]i modulation controlled by the attractants is not well defined. Here, we examined receptive mechanisms for the sperm attractant, SAAF, in the ascidian, Ciona intestinalis, and identified a plasma membrane Ca2+-ATPase (PMCA) as a SAAF-binding protein. PMCA is localized in sperm flagella membranes and seems to interact with SAAF through basic amino acids located in the second and third extracellular loops. ATPase activity of PMCA was enhanced by SAAF, and PMCA inhibitors, 5(6)-Carboxyeosin diacetate and Caloxin 2A1, inhibited chemotactic behavior of the sperm. Furthermore, Caloxin 2A1 seemed to inhibit efflux of [Ca2+]i in the sperm, and SAAF seemed to competitively reduce the effect of Caloxin 2A1. On the other hand, chemotactic behavior of the sperm was disordered not only at low-Ca2+, but also at high-Ca2+ conditions. Thus, PMCA is a potent candidate for the SAAF receptor, and direct control of Ca2+ efflux via PMCA is a fundamental mechanism to mediate chemotactic behavior in the ascidian spermatozoa.
Collapse
Affiliation(s)
- Kaoru Yoshida
- Faculty of Biomedical Engineering, Toin University of Yokohama, Yokohama, Kanagawa, 225-8503, Japan
| | - Kogiku Shiba
- Misaki Marine Biological Station, School of Science, the University of Tokyo, Miura, Kanagawa, 238-0225, Japan
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, 415-0025, Japan
| | - Ayako Sakamoto
- Misaki Marine Biological Station, School of Science, the University of Tokyo, Miura, Kanagawa, 238-0225, Japan
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, Yokohama, Kanagawa, 230-0045, Japan
| | - Jumpei Ikenaga
- Misaki Marine Biological Station, School of Science, the University of Tokyo, Miura, Kanagawa, 238-0225, Japan
| | - Shigeru Matsunaga
- Misaki Marine Biological Station, School of Science, the University of Tokyo, Miura, Kanagawa, 238-0225, Japan
- Central Research Laboratory, Hamamatsu Photonics K.K., Hamamatsu, Shizuoka, 434-8601, Japan
| | - Kazuo Inaba
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, 415-0025, Japan
| | - Manabu Yoshida
- Misaki Marine Biological Station, School of Science, the University of Tokyo, Miura, Kanagawa, 238-0225, Japan.
| |
Collapse
|
12
|
Crystal structure of a Ca 2+-dependent regulator of flagellar motility reveals the open-closed structural transition. Sci Rep 2018; 8:2014. [PMID: 29386625 PMCID: PMC5792641 DOI: 10.1038/s41598-018-19898-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 01/10/2018] [Indexed: 12/28/2022] Open
Abstract
Sperm chemotaxis toward a chemoattractant is very important for the success of fertilization. Calaxin, a member of the neuronal calcium sensor protein family, directly acts on outer-arm dynein and regulates specific flagellar movement during sperm chemotaxis of ascidian, Ciona intestinalis. Here, we present the crystal structures of calaxin both in the open and closed states upon Ca2+ and Mg2+ binding. The crystal structures revealed that three of the four EF-hands of a calaxin molecule bound Ca2+ ions and that EF2 and EF3 played a critical role in the conformational transition between the open and closed states. The rotation of α7 and α8 helices induces a significant conformational change of a part of the α10 helix into the loop. The structural differences between the Ca2+- and Mg2+-bound forms indicates that EF3 in the closed state has a lower affinity for Mg2+, suggesting that calaxin tends to adopt the open state in Mg2+-bound form. SAXS data supports that Ca2+-binding causes the structural transition toward the closed state. The changes in the structural transition of the C-terminal domain may be required to bind outer-arm dynein. These results provide a novel mechanism for recognizing a target protein using a calcium sensor protein.
Collapse
|
13
|
Network model predicts that CatSper is the main Ca 2+ channel in the regulation of sea urchin sperm motility. Sci Rep 2017; 7:4236. [PMID: 28652586 PMCID: PMC5484689 DOI: 10.1038/s41598-017-03857-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 05/08/2017] [Indexed: 12/27/2022] Open
Abstract
Spermatozoa sea urchin swimming behaviour is regulated by small peptides from the egg outer envelope. Speract, such a peptide, after binding to its receptor in Strongylocentrotus purpuratus sperm flagella, triggers a signaling pathway that culminates with a train of intracellular calcium oscillations, correlated with changes in sperm swimming pattern. This pathway has been widely studied but not fully characterized. Recent work on Arbacia punctulata sea urchin spermatozoa has documented the presence of the Ca2+ CatSper channel in their flagella and its involvement in chemotaxis. However, if other calcium channels participate in chemotaxis remains unclear. Here, based on an experimentally-backed logical network model, we conclude that CatSper is fundamental in the S. purpuratus speract-activated sea urchin sperm signaling cascade, although other Ca2+ channels could still be relevant. We also present for the first time experimental corroboration of its active presence in S. purpuratus sperm flagella. We argue, prompted by in silico knock-out calculations, that CatSper is the main generator of calcium oscillations in the signaling pathway and that other calcium channels, if present, have a complementary role. The approach adopted here allows us to unveil processes, which are hard to detect exclusively by experimental procedures.
Collapse
|
14
|
Matsuzaki M, Mizushima S, Hiyama G, Hirohashi N, Shiba K, Inaba K, Suzuki T, Dohra H, Ohnishi T, Sato Y, Kohsaka T, Ichikawa Y, Atsumi Y, Yoshimura T, Sasanami T. Lactic acid is a sperm motility inactivation factor in the sperm storage tubules. Sci Rep 2015; 5:17643. [PMID: 26619826 PMCID: PMC4664960 DOI: 10.1038/srep17643] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 11/03/2015] [Indexed: 12/23/2022] Open
Abstract
Although successful fertilization depends on timely encounters between sperm and egg, the decoupling of mating and fertilization often confers reproductive advantages to internally fertilizing animals. In several vertebrate groups, postcopulatory sperm viability is prolonged by storage in specialized organs within the female reproductive tract. In birds, ejaculated sperm can be stored in a quiescent state within oviductal sperm storage tubules (SSTs), thereby retaining fertilizability for up to 15 weeks at body temperature (41 °C); however, the mechanism by which motile sperm become quiescent within SSTs is unknown. Here, we show that low oxygen and high lactic acid concentrations are established in quail SSTs. Flagellar quiescence was induced by lactic acid in the concentration range found in SSTs through flagellar dynein ATPase inactivation following cytoplasmic acidification (<pH 6.0). The long-term preservation of sperm morphology under hypoxic and high temperature conditions indicates that a combination of these factors enables sperm cells to survive during the ovulation cycles. Our findings suggested a novel physiological role for lactic acid in promoting sperm quiescence in SSTs and opened up a new opportunity for technological improvement in prolonging sperm longevity at ambient or body temperature.
Collapse
Affiliation(s)
- Mei Matsuzaki
- Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka, Shizuoka 422-8529, Japan.,United Graduate School of Agricultural Science, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Shusei Mizushima
- Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka, Shizuoka 422-8529, Japan
| | - Gen Hiyama
- Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka, Shizuoka 422-8529, Japan
| | - Noritaka Hirohashi
- Oki Marine Biological Station, Education and Research Center for Biological Resources, Faculty of Life and Environmental Science, Shimane University, 194 Kamo, Okinoshima-cho, Oki, Shimane 685-0024, Japan
| | - Kogiku Shiba
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka 415-0025, Japan
| | - Kazuo Inaba
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka 415-0025, Japan
| | - Tomohiro Suzuki
- Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Shizuoka, Shizuoka 422-8529, Japan
| | - Hideo Dohra
- Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Shizuoka, Shizuoka 422-8529, Japan
| | - Toshiyuki Ohnishi
- Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka, Shizuoka 422-8529, Japan.,Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Shizuoka, Shizuoka 422-8529, Japan
| | - Yoshikatsu Sato
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Tetsuya Kohsaka
- Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka, Shizuoka 422-8529, Japan
| | - Yoshinobu Ichikawa
- Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka, Shizuoka 422-8529, Japan
| | - Yusuke Atsumi
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Takashi Yoshimura
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.,Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Tomohiro Sasanami
- Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka, Shizuoka 422-8529, Japan
| |
Collapse
|
15
|
González-Cota AL, Silva PÂ, Carneiro J, Darszon A. Single cell imaging reveals that the motility regulator speract induces a flagellar alkalinization that precedes and is independent of Ca²⁺ influx in sea urchin spermatozoa. FEBS Lett 2015; 589:2146-54. [PMID: 26143372 DOI: 10.1016/j.febslet.2015.06.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 06/18/2015] [Accepted: 06/18/2015] [Indexed: 02/06/2023]
Abstract
Speract, a peptide from the egg jelly coat of certain sea urchin species, modulates sperm motility through a signaling pathway involving several ionic fluxes leading to pHi and [Ca²⁺]i increases. [Ca²⁺]i oscillations in the flagellum regulate its beating pattern modulating sperm swimming. Recent evidence showed the importance of pHi in controlling Ca²⁺ influx and chemotaxis. However, spatio-temporal characterization of the flagellar pHi increase triggered by speract, and its correlation to that of [Ca²⁺]i is lacking. Here, we show for the first time in single sea urchin spermatozoa that the speract-induced flagellar pHi increase precedes and is independent of [Ca²⁺]i increase. Our results support a leading role of pHi in modulating the Ca²⁺ signals that govern sperm swimming.
Collapse
Affiliation(s)
- Ana Laura González-Cota
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Avenida Universidad 2001, Col. Chamilpa, C.P. 62210 Cuernavaca, Mor., México
| | | | | | - Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Avenida Universidad 2001, Col. Chamilpa, C.P. 62210 Cuernavaca, Mor., México.
| |
Collapse
|
16
|
Beltrán C, Rodríguez-Miranda E, Granados-González G, de De la Torre LG, Nishigaki T, Darszon A. Zn(2+) induces hyperpolarization by activation of a K(+) channel and increases intracellular Ca(2+) and pH in sea urchin spermatozoa. Dev Biol 2014; 394:15-23. [PMID: 25092071 PMCID: PMC4163537 DOI: 10.1016/j.ydbio.2014.07.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 07/01/2014] [Accepted: 07/24/2014] [Indexed: 11/24/2022]
Abstract
Zinc (Zn(2+)) has been recently recognized as a crucial element for male gamete function in many species although its detailed mechanism of action is poorly understood. In sea urchin spermatozoa, Zn(2+) was reported as an essential trace ion for efficient sperm motility initiation and the acrosome reaction by modulating intracellular pH (pHi). In this study we found that submicromolar concentrations of free Zn(2+) change membrane potential (Em) and increase the concentration of intracellular Ca(2+) ([Ca(2+)]i) and cAMP in Lytechinus pictus sperm. Our results indicate that the Zn(2+) response in sperm of this species mainly involves an Em hyperpolarization caused by K(+) channel activation. The pharmacological profile of the Zn(2+)-induced hyperpolarization indicates that the cGMP-gated K(+) selective channel (tetraKCNG/CNGK), which is crucial for speract signaling, is likely a main target for Zn(2+). Considering that Zn(2+) also induces [Ca(2+)]i fluctuations, our observations suggest that Zn(2+) activates the signaling cascade of speract, except for an increase in cGMP, and facilitates sperm motility initiation upon spawning. These findings provide new insights about the role of Zn(2+) in male gamete function.
Collapse
Affiliation(s)
- Carmen Beltrán
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos CP 62210, México
| | - Esmeralda Rodríguez-Miranda
- Departamento de Medicina y Nutrición, División de Ciencias de la Salud, Universidad de Guanajuato; Campus León. Guanajuato CP 37320, México
| | - Gisela Granados-González
- Facultad de Ciencias, Universidad Autónoma del Estado de México, Toluca, Estado de México CP 50000, México
| | | | - Takuya Nishigaki
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos CP 62210, México
| | - Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos CP 62210, México
| |
Collapse
|
17
|
In silico determination of the effect of multi-target drugs on calcium dynamics signaling network underlying sea urchin spermatozoa motility. PLoS One 2014; 9:e104451. [PMID: 25162222 PMCID: PMC4146467 DOI: 10.1371/journal.pone.0104451] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Accepted: 07/08/2014] [Indexed: 11/19/2022] Open
Abstract
The motility of spermatozoa of both Lytechinus pictus and Strongylocentrotus purpuratus sea urchin species is modulated by the egg-derived decapeptide speract via an oscillatory [Ca2+]-dependent signaling pathway. Comprehension of this pathway is hence directly related to the understanding of regulated sperm swimming. Niflumic acid (NFA), a nonsteroidal anti-inflammatory drug alters several ion channels. Though unspecific, NFA profoundly affects how sea urchin sperm respond to speract, increasing the [Ca2+]i oscillation period, amplitude, peak and average level values of the responses in immobilized and swimming cells. A previous logical network model we developed for the [Ca2+] dynamics of speract signaling cascade in sea urchin sperm allows integrated dissection of individual and multiple actions of NFA. Among the channels affected by NFA are: hyperpolarization-activated and cyclic nucleotide gated Na+ channels (HCN), [Ca2+]-dependent Cl- channels (CaCC) and [Ca2+]-dependent K+ channels (CaKC), all present in the sea urchin genome. Here, using our model we investigated the effect of blocking in silico HCN and CaCC channels suggested by experiments. Regarding CaKC channels, arguments can be provided for either their blockage or activation by NFA. Our study yielded two scenarios compliant with experimental observations: i) under CaKC inhibition, this [Ca2+]-dependent K+ channel should be different from the Slo1 channel and ii) under activation of the CaKC channel, another [Ca2+] channel not considered previously in the network is required, such as the pH-dependent CatSper channel. Additionally, our findings predict cause-effect relations resulting from a selective inhibition of those channels. Knowledge of these relations may be of consequence for a variety of electrophysiological studies and have an impact on drug related investigations. Our study contributes to a better grasp of the network dynamics and suggests further experimental work.
Collapse
|
18
|
Nishigaki T, José O, González-Cota AL, Romero F, Treviño CL, Darszon A. Intracellular pH in sperm physiology. Biochem Biophys Res Commun 2014; 450:1149-58. [PMID: 24887564 PMCID: PMC4146485 DOI: 10.1016/j.bbrc.2014.05.100] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 05/22/2014] [Indexed: 10/25/2022]
Abstract
Intracellular pH (pHi) regulation is essential for cell function. Notably, several unique sperm ion transporters and enzymes whose elimination causes infertility are either pHi dependent or somehow related to pHi regulation. Amongst them are: CatSper, a Ca(2+) channel; Slo3, a K(+) channel; the sperm-specific Na(+)/H(+) exchanger and the soluble adenylyl cyclase. It is thus clear that pHi regulation is of the utmost importance for sperm physiology. This review briefly summarizes the key components involved in pHi regulation, their characteristics and participation in fundamental sperm functions such as motility, maturation and the acrosome reaction.
Collapse
Affiliation(s)
- Takuya Nishigaki
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
| | - Omar José
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
| | - Ana Laura González-Cota
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
| | - Francisco Romero
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
| | - Claudia L Treviño
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
| | - Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico.
| |
Collapse
|
19
|
Vacquier VD, Loza-Huerta A, García-Rincón J, Darszon A, Beltrán C. Soluble adenylyl cyclase of sea urchin spermatozoa. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2621-8. [PMID: 25064590 DOI: 10.1016/j.bbadis.2014.07.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 07/07/2014] [Accepted: 07/15/2014] [Indexed: 02/05/2023]
Abstract
Fertilization, a key step in sexual reproduction, requires orchestrated changes in cAMP concentrations. It is notable that spermatozoa (sperm) are among the cell types with extremely high adenylyl cyclase (AC) activity. As production and consumption of this second messenger need to be locally regulated, the discovery of soluble AC (sAC) has broadened our understanding of how such cells deal with these requirements. In addition, because sAC is directly regulated by HCO(3)(-) it is able to translate CO₂/HCO(3)(-)/pH changes into cAMP levels. Fundamental sperm functions such as maturation, motility regulation and the acrosome reaction are influenced by cAMP; this is especially true for sperm of the sea urchin (SU), an organism that has been a model in the study of fertilization for more than 130 years. Here we summarize the discovery and properties of SU sperm sAC, and discuss its involvement in sperm physiology. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.
Collapse
Affiliation(s)
- Victor D Vacquier
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0202, USA.
| | - Arlet Loza-Huerta
- Departamento de Neurociencia Cognitiva, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Distrito Federal 04510, Mexico.
| | - Juan García-Rincón
- Departamento de Genética del Desarrollo y Fisiología Molecular, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, Mexico.
| | - Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, Mexico.
| | - Carmen Beltrán
- Departamento de Genética del Desarrollo y Fisiología Molecular, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, Mexico.
| |
Collapse
|
20
|
Sugiyama H, Chandler DE. Sperm guidance to the egg finds calcium at the helm. PROTOPLASMA 2014; 251:461-475. [PMID: 24085342 DOI: 10.1007/s00709-013-0550-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 09/05/2013] [Indexed: 06/02/2023]
Abstract
Sperm respond to multiple cues during guidance to the egg including chemical attractants, temperature, and fluid flow. Of these, sperm chemotaxis has been studied most extensively-over 100 years-but only recently has it started to be understood at the molecular level. The long gestation in this understanding has largely been due to technical limitations that include the detection of calcium signal dynamics in a relatively small structure-the flagellum, measurement of actual chemoattractant gradients, the fact that only subpopulations of sperm respond at any given time, and the diversity in swimming behaviors that sperm exhibit from different species. Today, measurements of flagellar calcium signals on a fast time scale, discovery of the ion channels and organelles that may regulate these signals, and better understanding and quantitation of sperm swimming behaviors involved have given more certainty to our understanding of sperm directional swimming and its control by characteristic, calcium-directed asymmetric flagellar bends. Future research will need to apply these technical advances to other forms of sperm guidance such as thermotaxis and rheotaxis as well as gaining an understanding of how the flagellar apparatus is controlled by calcium.
Collapse
Affiliation(s)
- Hitoshi Sugiyama
- Science and Technology Group, Okinawa Institute of Science and Technology, Okinawa, 904-0495, Japan
| | | |
Collapse
|
21
|
Affiliation(s)
- U B Kaupp
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research, 53175 Bonn, Germany
| |
Collapse
|
22
|
Balderas E, Sánchez-Cárdenas C, Chávez J, de la Vega Beltrán J, Gómez-Lagunas F, Treviño C, Darszon A. The anti-inflammatory drug celecoxib inhibits t-type Ca2+
currents in spermatogenic cells yet it elicits the acrosome reaction in mature sperm. FEBS Lett 2013; 587:2412-9. [DOI: 10.1016/j.febslet.2013.05.068] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 05/28/2013] [Accepted: 05/30/2013] [Indexed: 11/27/2022]
|
23
|
Kashikar ND, Alvarez L, Seifert R, Gregor I, Jäckle O, Beyermann M, Krause E, Kaupp UB. Temporal sampling, resetting, and adaptation orchestrate gradient sensing in sperm. ACTA ACUST UNITED AC 2013; 198:1075-91. [PMID: 22986497 PMCID: PMC3444779 DOI: 10.1083/jcb.201204024] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Sperm use temporal sampling, resetting of intracellular calcium level, and adaptation of their sensitivity to respond to a wide range of chemoattractant concentrations during their voyage toward the egg. Sperm, navigating in a chemical gradient, are exposed to a periodic stream of chemoattractant molecules. The periodic stimulation entrains Ca2+ oscillations that control looping steering responses. It is not known how sperm sample chemoattractant molecules during periodic stimulation and adjust their sensitivity. We report that sea urchin sperm sampled molecules for 0.2–0.6 s before a Ca2+ response was produced. Additional molecules delivered during a Ca2+ response reset the cell by causing a pronounced Ca2+ drop that terminated the response; this reset was followed by a new Ca2+ rise. After stimulation, sperm adapted their sensitivity following the Weber–Fechner law. Taking into account the single-molecule sensitivity, we estimate that sperm can register a minimal gradient of 0.8 fM/µm and be attracted from as far away as 4.7 mm. Many microorganisms sense stimulus gradients along periodic paths to translate a spatial distribution of the stimulus into a temporal pattern of the cell response. Orchestration of temporal sampling, resetting, and adaptation might control gradient sensing in such organisms as well.
Collapse
Affiliation(s)
- Nachiket D Kashikar
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research, 53175 Bonn, Germany
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Guerrero A, Espinal J, Wood CD, Rendón JM, Carneiro J, Martínez-Mekler G, Darszon A. Niflumic acid disrupts marine spermatozoan chemotaxis without impairing the spatiotemporal detection of chemoattractant gradients. J Cell Sci 2013; 126:1477-87. [DOI: 10.1242/jcs.121442] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In many broadcast-spawning marine organisms, oocytes release chemicals that guide conspecific spermatozoa towards their source through chemotaxis. In the sea urchin Lytechinus pictus, the chemoattractant peptide speract triggers a train of fluctuations of intracellular Ca2+ concentration in the sperm flagella. Each transient Ca2+ elevation leads to a momentary increase in flagellar bending asymmetry, known as a chemotactic turn. Furthermore, chemotaxis requires a precise spatiotemporal coordination between the Ca2+-dependent turns and the form of chemoattractant gradient. Spermatozoa that display Ca2+-dependent turns while swimming down the chemoattractant gradient, and conversely suppress turning events while swimming up gradient, successfully approach the center of the gradient. Previous experiments in Strongylocentrotus purpuratus sea urchin spermatozoa showed that niflumic acid (NFA), an inhibitor of several ion channels, drastically altered the speract-induced Ca2+ fluctuations and swimming patterns. In this study, mathematical modeling of the speract-dependent Ca2+ signaling pathway suggests that NFA, by potentially affecting HCN, CaCC and CaKC channels, may alter the temporal organization of Ca2+ fluctuations, and therefore disrupt chemotaxis. Here we investigate our hypothesis using a novel automated method for analyzing sperm behavior. We show that NFA does indeed disrupt chemotactic responses of L. pictus spermatozoa, although the temporal coordination between the Ca2+-dependent turns and the form of chemoattractant gradient is unaltered. Instead, NFA disrupts sperm chemotaxis by altering the arc length traveled during each chemotactic turning event. This alteration in the chemotactic turn trajectory disorientates spermatozoa at the termination of the turning event. We conclude that NFA disrupts chemotaxis without affecting how the spermatozoa decode environmental cues.
Collapse
|
25
|
Servin-Vences MR, Tatsu Y, Ando H, Guerrero A, Yumoto N, Darszon A, Nishigaki T. A caged progesterone analog alters intracellular Ca2+ and flagellar bending in human sperm. Reproduction 2012; 144:101-9. [PMID: 22580372 DOI: 10.1530/rep-11-0268] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Progesterone is a physiological agonist for mammalian sperm, modulating its flagellar movement and facilitating the acrosome reaction. To study the initial action of progesterone, we developed a caged analog with a photosensitive group: nitrophenylethanediol, at position 20. Using this compound combined with stroboscopic illumination, we performed Ca(2)(+) imaging of human spermatozoa and analyzed the effects of progesterone on the intracellular Ca(2)(+) concentration ([Ca(2)(+)](i)) of beating flagella for the first time. We observed a transient [Ca(2)(+)](i) increase in the head and the flagellum upon photolysis of the caged progesterone and an increase in flagellar curvature. Detailed kinetic analysis revealed that progesterone elicits an increase in the [Ca(2)(+)](i) immediately in the flagellum (mid-piece and principal piece), thereafter in the head with a short time lag. This observation is different from the progesterone-induced Ca(2)(+) mobilization in mouse spermatozoa, where the Ca(2)(+) rise initiates at the base of the sperm head. Our finding is mostly consistent with the recent discovery that progesterone activates CatSper channels in human spermatozoa, but not in mouse spermatozoa.
Collapse
Affiliation(s)
- M Rocio Servin-Vences
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Apdo Postal 510-3, Cuernavaca, Morelos 62250, Mexico
| | | | | | | | | | | | | |
Collapse
|
26
|
Maitrani C, Heyes DJ, Hay S, Arumugam S, Popik VV, Phillips RS. Preparation and photophysical properties of a caged kynurenine. Bioorg Med Chem Lett 2012; 22:2734-7. [PMID: 22444682 DOI: 10.1016/j.bmcl.2012.02.097] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 02/24/2012] [Accepted: 02/28/2012] [Indexed: 01/30/2023]
Abstract
We have prepared l-kyurenine 4-hydroxyphenacyl ester, a caged derivative of L-kynurenine. N(α)-tBOC-L-tryptophan was reacted with 4-hydroxyphenacyl bromide in DMF with K(2)CO(3) as the base to give the N(α)-tBOC 4-hydroxyphenacyl ester. The ester was then treated with O(3) in MeOH at -20°C, followed by trifluoroacetic acid in CH(2)Cl(2), then aqueous HCl to obtain the caged kynurenine as the dihydrochloride salt. The caged kynurenine is stable as a dry solid in the dark at -78°C, but in aqueous solutions in phosphate buffer at pH 7-8 hydrolyzes rapidly (t(1/2) ∼5 min). Solutions in Tris at pH 7 are more stable (t(1/2) >30 min), and solutions in 1mM HCl are stable for several hours. As expected, the ester is cleaved in microseconds with laser pulses at 355 nm. The caged kynurenine may be useful for preparation of substrate complexes for crystallography or in biological studies on kynurenine.
Collapse
Affiliation(s)
- Chandan Maitrani
- Department of Chemistry, University of Georgia, Athens, GA 30602, USA
| | | | | | | | | | | |
Collapse
|
27
|
Alvarez L, Dai L, Friedrich BM, Kashikar ND, Gregor I, Pascal R, Kaupp UB. The rate of change in Ca(2+) concentration controls sperm chemotaxis. ACTA ACUST UNITED AC 2012; 196:653-63. [PMID: 22371558 PMCID: PMC3307702 DOI: 10.1083/jcb.201106096] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sperm navigate in a chemoattractant gradient by translating changes in intracellular calcium concentration over time into changes in curvature of the swimming path. During chemotaxis and phototaxis, sperm, algae, marine zooplankton, and other microswimmers move on helical paths or drifting circles by rhythmically bending cell protrusions called motile cilia or flagella. Sperm of marine invertebrates navigate in a chemoattractant gradient by adjusting the flagellar waveform and, thereby, the swimming path. The waveform is periodically modulated by Ca2+ oscillations. How Ca2+ signals elicit steering responses and shape the path is unknown. We unveil the signal transfer between the changes in intracellular Ca2+ concentration ([Ca2+]i) and path curvature (κ). We show that κ is modulated by the time derivative d[Ca2+]i/dt rather than the absolute [Ca2+]i. Furthermore, simulation of swimming paths using various Ca2+ waveforms reproduces the wealth of swimming paths observed for sperm of marine invertebrates. We propose a cellular mechanism for a chemical differentiator that computes a time derivative. The cytoskeleton of cilia, the axoneme, is highly conserved. Thus, motile ciliated cells in general might use a similar cellular computation to translate changes of [Ca2+]i into motion.
Collapse
Affiliation(s)
- Luis Alvarez
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), 53175 Bonn, Germany.
| | | | | | | | | | | | | |
Collapse
|
28
|
|
29
|
Darszon A, Nishigaki T, Beltran C, Treviño CL. Calcium Channels in the Development, Maturation, and Function of Spermatozoa. Physiol Rev 2011; 91:1305-55. [DOI: 10.1152/physrev.00028.2010] [Citation(s) in RCA: 269] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A proper dialogue between spermatozoa and the egg is essential for conception of a new individual in sexually reproducing animals. Ca2+ is crucial in orchestrating this unique event leading to a new life. No wonder that nature has devised different Ca2+-permeable channels and located them at distinct sites in spermatozoa so that they can help fertilize the egg. New tools to study sperm ionic currents, and image intracellular Ca2+ with better spatial and temporal resolution even in swimming spermatozoa, are revealing how sperm ion channels participate in fertilization. This review critically examines the involvement of Ca2+ channels in multiple signaling processes needed for spermatozoa to mature, travel towards the egg, and fertilize it. Remarkably, these tiny specialized cells can express exclusive channels like CatSper for Ca2+ and SLO3 for K+, which are attractive targets for contraception and for the discovery of novel signaling complexes. Learning more about fertilization is a matter of capital importance; societies face growing pressure to counteract rising male infertility rates, provide safe male gamete-based contraceptives, and preserve biodiversity through improved captive breeding and assisted conception initiatives.
Collapse
Affiliation(s)
- Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Takuya Nishigaki
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Carmen Beltran
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Claudia L. Treviño
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| |
Collapse
|
30
|
Espinal J, Aldana M, Guerrero A, Wood C, Darszon A, Martínez-Mekler G. Discrete dynamics model for the speract-activated Ca2+ signaling network relevant to sperm motility. PLoS One 2011; 6:e22619. [PMID: 21857937 PMCID: PMC3156703 DOI: 10.1371/journal.pone.0022619] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 06/26/2011] [Indexed: 01/05/2023] Open
Abstract
Understanding how spermatozoa approach the egg is a central biological issue. Recently a considerable amount of experimental evidence has accumulated on the relation between oscillations in intracellular calcium ion concentration ([Ca]) in the sea urchin sperm flagellum, triggered by peptides secreted from the egg, and sperm motility. Determination of the structure and dynamics of the signaling pathway leading to these oscillations is a fundamental problem. However, a biochemically based formulation for the comprehension of the molecular mechanisms operating in the axoneme as a response to external stimulus is still lacking. Based on experiments on the S. purpuratus sea urchin spermatozoa, we propose a signaling network model where nodes are discrete variables corresponding to the pathway elements and the signal transmission takes place at discrete time intervals according to logical rules. The validity of this model is corroborated by reproducing previous empirically determined signaling features. Prompted by the model predictions we performed experiments which identified novel characteristics of the signaling pathway. We uncovered the role of a high voltage-activated channel as a regulator of the delay in the onset of fluctuations after activation of the signaling cascade. This delay time has recently been shown to be an important regulatory factor for sea urchin sperm reorientation. Another finding is the participation of a voltage-dependent calcium-activated channel in the determination of the period of the fluctuations. Furthermore, by analyzing the spread of network perturbations we find that it operates in a dynamically critical regime. Our work demonstrates that a coarse-grained approach to the dynamics of the signaling pathway is capable of revealing regulatory sperm navigation elements and provides insight, in terms of criticality, on the concurrence of the high robustness and adaptability that the reproduction processes are predicted to have developed throughout evolution.
Collapse
Affiliation(s)
- Jesús Espinal
- Instituto de Ciencias Fsicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- Centro de Ciencias de la Complejidad, Ciudad Universitaria, México, México
| | - Maximino Aldana
- Instituto de Ciencias Fsicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- Centro de Ciencias de la Complejidad, Ciudad Universitaria, México, México
| | - Adán Guerrero
- Departamento de Genética del Desarrollo y Fisiologa Molecular, Instituto de Biotecnologa, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Christopher Wood
- Departamento de Genética del Desarrollo y Fisiologa Molecular, Instituto de Biotecnologa, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiologa Molecular, Instituto de Biotecnologa, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Gustavo Martínez-Mekler
- Instituto de Ciencias Fsicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- Centro de Ciencias de la Complejidad, Ciudad Universitaria, México, México
- Centro Internacional de Ciencias, Cuernavaca, Morelos, México
- * E-mail:
| |
Collapse
|
31
|
Yoshida M, Yoshida K. Sperm chemotaxis and regulation of flagellar movement by Ca2+. Mol Hum Reprod 2011; 17:457-65. [PMID: 21610215 DOI: 10.1093/molehr/gar041] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Manabu Yoshida
- Misaki Marine Biological Station, Graduate School of Science, University of Tokyo, Miura, Kanagawa 238-0225, Japan.
| | | |
Collapse
|
32
|
Abstract
Sperm chemotaxis is a long-term puzzle and most of our knowledge comes from studying marine animals that are external fertilizers. Sperm are attracted by diffusible chemical factors (chemoattractants) released from the egg which redirect their swimming paths towards their source. This redirection is driven by increases in flagellar curvature that correlate with transient flagellar Ca(2+) increases. Recent experimental and modelling results provide insights into the signal flow underlying the translation of an external chemical gradient into an intracellular molecular and motor response. A fundamental element of sea-urchin sperm chemotaxis lies in the ability of these cells to suppress Ca(2+)-mediated increases in flagellar curvature while experiencing an increasing chemoattractant gradient. The article considers this new evidence and summarizes the known underlying cellular mechanisms and behavioural strategies that sperm use to locate and fertilize the oocyte.
Collapse
|
33
|
Guerrero A, Nishigaki T, Carneiro J, Yoshiro Tatsu, Wood CD, Darszon A. Tuning sperm chemotaxis by calcium burst timing. Dev Biol 2010; 344:52-65. [DOI: 10.1016/j.ydbio.2010.04.013] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 04/08/2010] [Accepted: 04/12/2010] [Indexed: 12/20/2022]
|
34
|
Smith DJ, Gaffney EA, Gadêlha H, Kapur N, Kirkman-Brown JC. Bend propagation in the flagella of migrating human sperm, and its modulation by viscosity. ACTA ACUST UNITED AC 2009; 66:220-36. [DOI: 10.1002/cm.20345] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
35
|
Taniguchi A, Skwarczynski M, Sohma Y, Okada T, Ikeda K, Prakash H, Mukai H, Hayashi Y, Kimura T, Hirota S, Matsuzaki K, Kiso Y. Controlled Production of Amyloid β Peptide from a Photo-Triggered, Water-Soluble Precursor “Click Peptide“. Chembiochem 2008; 9:3055-65. [DOI: 10.1002/cbic.200800503] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
36
|
Shiba K, Baba SA, Inoue T, Yoshida M. Ca2+ bursts occur around a local minimal concentration of attractant and trigger sperm chemotactic response. Proc Natl Acad Sci U S A 2008; 105:19312-7. [PMID: 19047630 PMCID: PMC2614758 DOI: 10.1073/pnas.0808580105] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Indexed: 11/18/2022] Open
Abstract
Ca(2+) is known to have important roles in sperm chemotaxis, although the relationship between intracellular Ca(2+) concentration ([Ca(2+)](i)) and modulation of the swimming and chemotactic behavior of spermatozoa has not been elucidated. Using a high-speed Ca(2+) imaging system, we examined the chemotactic behavior and [Ca(2+)](i) in individual ascidian sperm cells exhibiting chemotactic responses toward sperm activating and attracting factor (SAAF), a chemoattractant released by eggs. In this study, we found that transient [Ca(2+)](i) increased in the flagellum (Ca(2+) bursts) concomitantly with a change in the swimming direction in an SAAF gradient field. During the initial phase of the Ca(2+) bursts, the flagellum of the spermatozoon exhibited highly asymmetric waveforms enabling the quick turning of the swimming path. However, the flagellum subsequently changed to symmetric beating, causing the spermatozoon to swim straight. Interestingly, during such responses, [Ca(2+)](i) remained higher than the basal level, indicating that the series of responses was not simply determined by Ca(2+) concentrations. Also, we found that Ca(2+) bursts were consistently evoked at points at which the spermatozoon attained around a temporally minimal value for a given SAAF concentration. We concluded that Ca(2+) bursts induced around a local minimal SAAF concentration trigger a sequence of flagellar responses comprising quick turning followed by straight swimming to direct spermatozoa efficiently toward eggs.
Collapse
Affiliation(s)
- Kogiku Shiba
- Misaki Marine Biological Station, Graduate School of Science, University of Tokyo, Miura, Kanagawa 238-0225, Japan
| | - Shoji A. Baba
- Department of Advanced Biosciences, Graduate School of Humanities and Sciences, Ochanomizu University, Bunkyo, Tokyo 112-8610, Japan; and
| | - Takafumi Inoue
- Department of Life Science and Bio-Science, Faculty of Science and Engineering, Waseda University, Shinjuku, Tokyo 162-8480, Japan
| | - Manabu Yoshida
- Misaki Marine Biological Station, Graduate School of Science, University of Tokyo, Miura, Kanagawa 238-0225, Japan
| |
Collapse
|
37
|
Hirohashi N, Kamei N, Kubo H, Sawada H, Matsumoto M, Hoshi M. Egg and sperm recognition systems during fertilization. Dev Growth Differ 2008; 50 Suppl 1:S221-38. [DOI: 10.1111/j.1440-169x.2008.01017.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
38
|
Furuta T, Watanabe T, Tanabe S, Sakyo J, Matsuba C. Phototriggers for nucleobases with improved photochemical properties. Org Lett 2007; 9:4717-20. [PMID: 17929824 DOI: 10.1021/ol702106t] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Synthesis and photochemical properties of new photoremovable protecting groups for nucleobases are described. Four caged 2'-deoxycytidines (dCs) were synthesized, and their photochemical properties were measured under simulated physiological conditions. Two new coumarin-caged dCs show better photochemical and photophysical properties than those of the caged dCs having previously reported caging groups.
Collapse
Affiliation(s)
- Toshiaki Furuta
- Department of Biomolecular Science and Research Center for Materials with Integrated Properties, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
| | | | | | | | | |
Collapse
|
39
|
Sohma Y, Kiso Y. "Click peptides"--chemical biology-oriented synthesis of Alzheimer's disease-related amyloid beta peptide (abeta) analogues based on the "O-acyl isopeptide method". Chembiochem 2007; 7:1549-57. [PMID: 16915597 DOI: 10.1002/cbic.200600112] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A clear understanding of the pathological mechanism of amyloid beta peptide (Abeta) 1-42, a currently unexplained process, would be of great significance for the discovery of novel drug targets for Alzheimer's disease (AD) therapy. To date, though, the elucidation of these Abeta1-42 dynamic events has been a difficult issue because of uncontrolled polymerization, which also poses a significant obstacle in establishing experimental systems with which to clarify the pathological function of Abeta1-42. We have recently developed chemical biology-oriented pH- or phototriggered "click peptide" isoform precursors of Abeta1-42, based on the "O-acyl isopeptide method", in which a native amide bond at a hydroxyamino acid residue, such as Ser, is isomerized to an ester bond, the target peptide subsequently being generated by an O-N intramolecular acyl migration reaction. These click peptide precursors did not exhibit any self-assembling character under physiological conditions, thanks to the presence of the one single ester bond, and were able to undergo migration to give the target Abeta1-42 in a quick and easy, one-way (so-called "click")conversion reaction. The use of click peptides could be a useful strategy to investigate the biological functions of Abeta1-42 in AD through inducible activation of Abeta1-42 self-assembly.
Collapse
Affiliation(s)
- Youhei Sohma
- Department of Medicinal Chemistry Center for Frontier Research in Medicinal Science 21st Century COE Program, Kyoto Pharmaceutical University Yamashina-ku, Kyoto 607-8412, Japan
| | | |
Collapse
|
40
|
Wood CD, Nishigaki T, Tatsu Y, Yumoto N, Baba SA, Whitaker M, Darszon A. Altering the speract-induced ion permeability changes that generate flagellar Ca2+ spikes regulates their kinetics and sea urchin sperm motility. Dev Biol 2007; 306:525-37. [PMID: 17467684 DOI: 10.1016/j.ydbio.2007.03.036] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Revised: 03/22/2007] [Accepted: 03/22/2007] [Indexed: 11/22/2022]
Abstract
Speract, an egg-derived sperm-activating peptide, induces changes in intracellular Ca2+, Na+, pH, cAMP, cGMP, and membrane potential in sperm of the sea urchin Strongylocentrotus purpuratus. Ca2+ is a key regulator of motility in all sperm and, in many marine species, is required for generating turns interspersed with straighter swimming paths that are essential for chemotaxis towards the egg. We show that speract triggers a train of increases in flagellar Ca2+, and that each individual Ca2+ fluctuation induces a transient increase in flagellar asymmetry that leads to a turn. We also find that modifying the amplitude, duration and interval between individual Ca2+ fluctuations by treating sperm with niflumic acid, an inhibitor of Ca2+-activated Cl(-) channels, correspondingly alters the properties of the sperm turns. We conclude that Ca2+ entry through a fast flagellar pathway not only induces sperm turns, but the kinetics of Ca2+ entry may shape the nature of these turns, and that these kinetics are tuned by other channels, possibly including Cl(-) channels. In addition, the speract-induced changes in sperm motility closely resemble those seen during chemotaxis in other marine organisms, yet speract is not a chemoattractant. This implies the Ca2+-induced motility changes are necessary but not sufficient for chemotaxis.
Collapse
Affiliation(s)
- Christopher D Wood
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo Postal 510-3, Cuernavaca, Morelos 62250, México.
| | | | | | | | | | | | | |
Collapse
|
41
|
Sohma Y, Yoshiya T, Taniguchi A, Kimura T, Hayashi Y, Kiso Y. Development of O-acyl isopeptide method. Biopolymers 2007; 88:253-62. [PMID: 17236207 DOI: 10.1002/bip.20683] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
During over a decade of study on aspartic protease inhibitors and water-soluble prodrugs, in 2003, we discovered that the presence of an O-acyl instead of N-acyl residue within the peptide backbone significantly changed the secondary structure of the native peptide. In addition, the target peptide was subsequently generated by an O-N intramolecular acyl migration reaction. These findings led to the development of a novel method, called "O-acyl isopeptide method," for the synthesis of peptides containing difficult sequence. Further application of the method to Alzheimer's Abeta1-42 revealed that the O-acyl isopeptide of Abeta1-42 could be effectively synthesized and stored without spontaneous self-assembly. Intact monomer Abeta1-42 could then be obtained from the isopeptide under physiological experimental conditions. We named the O-acyl isopeptide as "Click Peptide," because of its "quick and easy one-way conversion" to the parent Abeta1- 42. Application of the click peptide has provided a new basis for the investigation of the biological functions of Abeta1-42 by inducible activation of its self-assembly. The O-acyl isopeptide method has further evolved as a general method for peptides synthesis with our recent developments of "O-acyl isodipeptide units" and "racemization-free segment condensation methodology." Isodipeptide units have enabled routine use of the O-acyl isopeptide method by avoiding the often difficult esterification reaction on resin. "Racemizationfree segment condensation methodology" has been achieved by employing N-segments possessing a C-terminal urethaneprotected O-acyl Ser/Thr residues. The synthesis of long peptides/proteins by racemization-free segment condensation has thus become possible at Ser/Thr residues instead of Cterminal Gly/Pro residues. As the O-acyl isopeptide method becomes more widely utilized, we have composed this review to facilitate its application for the production of peptides and proteins.
Collapse
Affiliation(s)
- Youhei Sohma
- Department of Medicinal Chemistry, Center for Frontier Research in Medicinal Science, 21st Century COE Program, Kyoto Pharmaceutical University, Kyoto, Japan
| | | | | | | | | | | |
Collapse
|
42
|
Beltrán C, Galindo BE, Rodríguez-Miranda E, Sánchez D. Signal transduction mechanisms regulating ion fluxes in the sea urchin sperm. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/sita.200600129] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
43
|
Calcium and fertilization. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s0167-7306(06)41016-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
44
|
Shiba K, Márián T, Krasznai Z, Baba SA, Morisawa M, Yoshida M. Na+/Ca2+ exchanger modulates the flagellar wave pattern for the regulation of motility activation and chemotaxis in the ascidian spermatozoa. ACTA ACUST UNITED AC 2006; 63:623-32. [PMID: 16869011 DOI: 10.1002/cm.20149] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Ion channels and ion exchangers are known to be important participants in various aspects of sperm physiology, e.g. motility activation, chemotaxis, the maintenance of motility and the acrosome reaction in the sperm. We report here on a role of the K+ -independent Na+/Ca2+ exchanger (NCX) on ascidian sperm. Reverse-transcriptase PCR reveals that the NCX is expressed in the testis while immunoblotting and immunolocalization demonstrate that the NCX exists on the sperm in the ascidian Ciona savignyi and C. intestinalis. A potent blocker of the NCX, KB-R7943 was found to block sperm-activating and -attracting factor (SAAF)-induced motility activation, sperm motility and sperm chemotaxis. We further analyzed the effects of this blocker on motility parameters such as the flagellar waveform, curvature, beat frequency, amplitude and wavelength of the sperm flagella. Inhibition of the NCX caused two distinct effects: a low concentration of KB-R7943 induced symmetric bending, whereas a high concentration of KB-R7943 resulted in asymmetric flagellar bending. These findings suggest that the NCX plays important roles in the regulation of SAAF-induced sperm chemotaxis, motility activation and motility maintenance in the ascidian. This study provides new information toward an understanding of Ca2+ transport systems in sperm motility and chemotaxis.
Collapse
Affiliation(s)
- Kogiku Shiba
- Misaki Marine Biological Station, Graduate School of Science, University of Tokyo, Kanagawa, Japan
| | | | | | | | | | | |
Collapse
|
45
|
Darszon A, Acevedo JJ, Galindo BE, Hernández-González EO, Nishigaki T, Treviño CL, Wood C, Beltrán C. Sperm channel diversity and functional multiplicity. Reproduction 2006; 131:977-88. [PMID: 16735537 DOI: 10.1530/rep.1.00612] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ion channels are extraordinarily efficient machines that move ions in diversely controlled manners, allowing cells to rapidly exchange information with the outside world and with other cells. Communication is the currency of fertilization, as it is of most fundamental cell signaling events. Ion channels are deeply involved in the dialogue between sperm, its surroundings, and the egg. How sperm swim, find the egg and fertilize it depend on ion permeability changes modulated by environmental cues and components of the egg outer layer. Different ion channels distinctly localized in these tiny, amazing cells perform specific decoding functions that shape the sophisticated behavior of sperm. It is not surprising that certain sperm ion channels are turning out to be unique. New strategies to characterize sperm ion transport have opened exciting possibilities to dissect sperm-egg signaling and unveil novel contraception targets.
Collapse
Affiliation(s)
- Alberto Darszon
- Department of Genetics of Development and Molecular Physiology, Institute of Biotechnology, UNAM, Cuernavaca, Mexico
| | | | | | | | | | | | | | | |
Collapse
|
46
|
Kaupp UB, Hildebrand E, Weyand I. Sperm chemotaxis in marine invertebrates--molecules and mechanisms. J Cell Physiol 2006; 208:487-94. [PMID: 16619222 DOI: 10.1002/jcp.20669] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Sperm are attracted by chemical substances which are released by the egg. This process is called chemotaxis. Several molecules that are involved in chemotactic signaling of sperm from marine invertebrates are described and a model of the signaling pathway is presented. We discuss the motor response during chemotaxis and propose a model of the navigation strategy of sperm.
Collapse
Affiliation(s)
- U B Kaupp
- Institut für Biologische Informationsverarbeitung 1, Forschungszentrum Jülich, 52425 Jülich, Germany.
| | | | | |
Collapse
|
47
|
Nakachi M, Moriyama H, Hoshi M, Matsumoto M. Acrosome reaction is subfamily specific in sea star fertilization. Dev Biol 2006; 298:597-604. [PMID: 16934796 DOI: 10.1016/j.ydbio.2006.07.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 07/05/2006] [Accepted: 07/11/2006] [Indexed: 10/24/2022]
Abstract
In the fertilization process of sea stars, sperm is activated to go through the acrosome reaction before cell fusion. We focused on induction of the acrosome reaction as a key process in fertilization. Six species of sea stars were used in this study: Asterias amurensis, Asterias rubens, Asterias forbesi, Aphelasterias japonica, Distolasterias nipon, and Asterina pectinifera. Acrosome reaction assays indicate that the acrosome reaction can be induced across species within Asteriinae subfamily. However, cross-fertilization assays indicate that sea stars have species specificity in fertilization. Therefore, steps after the acrosome reaction are responsible for the species specificity. To explain acrosome reaction subfamily specificity at the molecular level, the sugar components of egg jelly were examined and analyzed by principal component analysis. A. amurensis and A. forbesi belong to the same induction group of the acrosome reaction. D. nipon and An. pectinifera are in a unique group. Enzyme-linked immunosorbent assays indicate that Asteriinae subfamily share a common glycan structure, the Fragment 1 of Acrosome Reaction-Inducing Substance from A. amurensis. Fragment 1 plays an important role in the subfamily specificity of acrosome reaction induction. In addition, A. amurensis sperm activating peptide was recognized by sperm from the same superorder. These results demonstrate that the specificity of acrosome reaction induction is present at the subfamily level in sea stars.
Collapse
Affiliation(s)
- Mia Nakachi
- Department of Biosciences and Informatics, Keio University, Hiyoshi, Kouhoku-ku, Yokohama 223-8522, Japan
| | | | | | | |
Collapse
|
48
|
Nomura M, Vacquier VD. Proteins associated with soluble adenylyl cyclase in sea urchin sperm flagella. ACTA ACUST UNITED AC 2006; 63:582-90. [PMID: 16847896 DOI: 10.1002/cm.20147] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Adenylyl cyclases (ACs) synthesize cAMP and are present in cells as transmembrane AC and soluble AC (sAC). In sperm, the cAMP produced regulates ion channels and it also activates protein kinase-A that in turn phosphorylates specific axonemal proteins to activate flagellar motility. In mammalian sperm, sAC localizes to the midpiece of flagella, whereas in sea urchin sperm sAC is along the entire flagellum. Here we show that in sea urchin sperm, sAC is complexed with proteins of the plasma membrane and axoneme. Immunoprecipitation shows that a minimum of 10 proteins is tightly associated with sAC. Mass spectrometry of peptides derived from these proteins shows them to be: axonemal dynein heavy chains 7 and 9, sperm specific Na+/H+ exchanger, cyclic nucleotide-gated ion channel, sperm specific creatine kinase, membrane bound guanylyl cyclase, cyclic GMP specific phosphodiesterase 5A, the receptor for the egg peptide speract, and alpha- and beta-tubulins. The sAC-associated proteins could be important in linking membrane signal transduction to energy utilisation in the regulation of flagellar motility.
Collapse
Affiliation(s)
- Mamoru Nomura
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093-0202, USA.
| | | |
Collapse
|
49
|
Abstract
Sperm become attracted by chemical substances that are released from the outer coating of the egg, a process called chemotaxis. In this paper the cellular pathway and the motor response during chemotaxis of sperm from sea urchin and starfish are briefly outlined.
Collapse
Affiliation(s)
- E Hildebrand
- Institut für Biologische Informationsverarbeitung, Forschungszentrum Jülich, Germany
| | | |
Collapse
|
50
|
Taniguchi A, Sohma Y, Kimura M, Okada T, Ikeda K, Hayashi Y, Kimura T, Hirota S, Matsuzaki K, Kiso Y. "Click peptide" based on the "o-acyl isopeptide method": control of A beta1-42 production from a photo-triggered A beta1-42 analogue. J Am Chem Soc 2006; 128:696-7. [PMID: 16417340 DOI: 10.1021/ja057100v] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A clear understanding of the dynamic events of amyloid beta peptide (Abeta) 1-42, such as the folding, self-assembly, and aggregation processes, would be of great significance in Alzheimer's disease (AD) research. However, elucidation of these Abeta1-42 dynamic events is a difficult issue due to uncontrolled polymerization, which also poses a significant obstacle for establishing an experimental system that clarifies the pathological function of Abeta1-42. On the basis of the O-acyl isopeptide method, we herein developed a novel photo-triggered "click peptide" of Abeta1-42, for example, 26-N-Nvoc-26-AIAbeta42, in which the photocleavable 6-nitroveratryloxycarbonyl (Nvoc) group was introduced at the alpha-amino group of Ser26 in 26-O-acyl isoAbeta1-42 (26-AIAbeta42). From the results, (1) the click peptide did not exhibit the self-assembling nature under physiological conditions due to one single modified ester; (2) photoirradiation of the click peptide and subsequent O-N intramolecular acyl migration afforded the intact Abeta1-42 with a quick and one-way conversion reaction (so-called "click"), while the click peptide was stable under nonphotolytic or storage conditions. In addition, it is advantageous that no additional fibril inhibitory auxiliaries were released during conversion to Abeta1-42. This method provides a novel system useful for investigating the dynamic biological functions of Abeta1-42 in AD by inducible activation of Abeta1-42 self-assembly.
Collapse
Affiliation(s)
- Atsuhiko Taniguchi
- Department of Medicinal Chemistry, Center for Frontier Research in Medicinal Science, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|