1
|
Nagel M, Niestroj M, Bansal R, Fleck D, Lampert A, Stopkova R, Stopka P, Ben-Shaul Y, Spehr M. Deciphering the chemical language of inbred and wild mouse conspecific scents. eLife 2024; 12:RP90529. [PMID: 38747258 PMCID: PMC11095937 DOI: 10.7554/elife.90529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024] Open
Abstract
In most mammals, conspecific chemosensory communication relies on semiochemical release within complex bodily secretions and subsequent stimulus detection by the vomeronasal organ (VNO). Urine, a rich source of ethologically relevant chemosignals, conveys detailed information about sex, social hierarchy, health, and reproductive state, which becomes accessible to a conspecific via vomeronasal sampling. So far, however, numerous aspects of social chemosignaling along the vomeronasal pathway remain unclear. Moreover, since virtually all research on vomeronasal physiology is based on secretions derived from inbred laboratory mice, it remains uncertain whether such stimuli provide a true representation of potentially more relevant cues found in the wild. Here, we combine a robust low-noise VNO activity assay with comparative molecular profiling of sex- and strain-specific mouse urine samples from two inbred laboratory strains as well as from wild mice. With comprehensive molecular portraits of these secretions, VNO activity analysis now enables us to (i) assess whether and, if so, how much sex/strain-selective 'raw' chemical information in urine is accessible via vomeronasal sampling; (ii) identify which chemicals exhibit sufficient discriminatory power to signal an animal's sex, strain, or both; (iii) determine the extent to which wild mouse secretions are unique; and (iv) analyze whether vomeronasal response profiles differ between strains. We report both sex- and, in particular, strain-selective VNO representations of chemical information. Within the urinary 'secretome', both volatile compounds and proteins exhibit sufficient discriminative power to provide sex- and strain-specific molecular fingerprints. While total protein amount is substantially enriched in male urine, females secrete a larger variety at overall comparatively low concentrations. Surprisingly, the molecular spectrum of wild mouse urine does not dramatically exceed that of inbred strains. Finally, vomeronasal response profiles differ between C57BL/6 and BALB/c animals, with particularly disparate representations of female semiochemicals.
Collapse
Affiliation(s)
- Maximilian Nagel
- Department of Chemosensation, Institute for Biology II, RWTH Aachen UniversityAachenGermany
| | - Marco Niestroj
- Department of Chemosensation, Institute for Biology II, RWTH Aachen UniversityAachenGermany
| | - Rohini Bansal
- Department of Medical Neurobiology, Institute for Medical Research Israel Canada, Faculty of Medicine, The Hebrew University of JerusalemJerusalemIsrael
| | - David Fleck
- Department of Chemosensation, Institute for Biology II, RWTH Aachen UniversityAachenGermany
| | - Angelika Lampert
- Institute of Neurophysiology, Uniklinik RWTH Aachen UniversityAachenGermany
- Research Training Group 2416 MultiSenses – MultiScales, RWTH Aachen UniversityAachenGermany
| | - Romana Stopkova
- BIOCEV group, Department of Zoology, Faculty of Science, Charles UniversityPragueCzech Republic
| | - Pavel Stopka
- BIOCEV group, Department of Zoology, Faculty of Science, Charles UniversityPragueCzech Republic
| | - Yoram Ben-Shaul
- Department of Medical Neurobiology, Institute for Medical Research Israel Canada, Faculty of Medicine, The Hebrew University of JerusalemJerusalemIsrael
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen UniversityAachenGermany
- Research Training Group 2416 MultiSenses – MultiScales, RWTH Aachen UniversityAachenGermany
| |
Collapse
|
2
|
Hamacher C, Degen R, Franke M, Switacz VK, Fleck D, Katreddi RR, Hernandez-Clavijo A, Strauch M, Horio N, Hachgenei E, Spehr J, Liberles SD, Merhof D, Forni PE, Zimmer-Bensch G, Ben-Shaul Y, Spehr M. A revised conceptual framework for mouse vomeronasal pumping and stimulus sampling. Curr Biol 2024; 34:1206-1221.e6. [PMID: 38320553 PMCID: PMC10965388 DOI: 10.1016/j.cub.2024.01.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 12/15/2023] [Accepted: 01/11/2024] [Indexed: 02/08/2024]
Abstract
The physiological performance of any sensory organ is determined by its anatomy and physical properties. Consequently, complex sensory structures with elaborate features have evolved to optimize stimulus detection. Understanding these structures and their physical nature forms the basis for mechanistic insights into sensory function. Despite its crucial role as a sensor for pheromones and other behaviorally instructive chemical cues, the vomeronasal organ (VNO) remains a poorly characterized mammalian sensory structure. Fundamental principles of its physico-mechanical function, including basic aspects of stimulus sampling, remain poorly explored. Here, we revisit the classical vasomotor pump hypothesis of vomeronasal stimulus uptake. Using advanced anatomical, histological, and physiological methods, we demonstrate that large parts of the lateral mouse VNO are composed of smooth muscle. Vomeronasal smooth muscle tissue comprises two subsets of fibers with distinct topography, structure, excitation-contraction coupling, and, ultimately, contractile properties. Specifically, contractions of a large population of noradrenaline-sensitive cells mediate both transverse and longitudinal lumen expansion, whereas cholinergic stimulation targets an adluminal group of smooth muscle fibers. The latter run parallel to the VNO's rostro-caudal axis and are ideally situated to mediate antagonistic longitudinal constriction of the lumen. This newly discovered arrangement implies a novel mode of function. Single-cell transcriptomics and pharmacological profiling reveal the receptor subtypes involved. Finally, 2D/3D tomography provides non-invasive insight into the intact VNO's anatomy and mechanics, enables measurement of luminal fluid volume, and allows an assessment of relative volume change upon noradrenergic stimulation. Together, we propose a revised conceptual framework for mouse vomeronasal pumping and, thus, stimulus sampling.
Collapse
Affiliation(s)
- Christoph Hamacher
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, 52074 Aachen, Germany
| | - Rudolf Degen
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, 52074 Aachen, Germany; Research Training Group 2416 MultiSenses - MultiScales, RWTH Aachen University, 52074 Aachen, Germany
| | - Melissa Franke
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, 52074 Aachen, Germany
| | - Victoria K Switacz
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, 52074 Aachen, Germany; Research Training Group 2416 MultiSenses - MultiScales, RWTH Aachen University, 52074 Aachen, Germany
| | - David Fleck
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, 52074 Aachen, Germany
| | - Raghu Ram Katreddi
- Department of Biological Sciences, The RNA Institute, University at Albany, Albany, NY 12222, USA
| | - Andres Hernandez-Clavijo
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, 52074 Aachen, Germany
| | - Martin Strauch
- Institute of Imaging and Computer Vision, RWTH Aachen University, 52074 Aachen, Germany
| | - Nao Horio
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Enno Hachgenei
- Department of Production Metrology, Fraunhofer Institute for Production Technology, 52074 Aachen, Germany
| | - Jennifer Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, 52074 Aachen, Germany
| | - Stephen D Liberles
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Dorit Merhof
- Research Training Group 2416 MultiSenses - MultiScales, RWTH Aachen University, 52074 Aachen, Germany; Institute of Imaging and Computer Vision, RWTH Aachen University, 52074 Aachen, Germany
| | - Paolo E Forni
- Department of Biological Sciences, The RNA Institute, University at Albany, Albany, NY 12222, USA
| | - Geraldine Zimmer-Bensch
- Research Training Group 2416 MultiSenses - MultiScales, RWTH Aachen University, 52074 Aachen, Germany; Department of Neuroepigenetics, Institute for Biology II, RWTH Aachen University, 52074 Aachen, Germany
| | - Yoram Ben-Shaul
- Department of Medical Neurobiology, Institute for Medical Research Israel Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, 52074 Aachen, Germany; Research Training Group 2416 MultiSenses - MultiScales, RWTH Aachen University, 52074 Aachen, Germany.
| |
Collapse
|
3
|
Abstract
Adenosine triphosphate (ATP) serves as the essential source of cellular energy. Over the last two decades, however, ATP has also attracted increasing interest as an extracellular signal that activates purinergic plasma membrane receptors of the P2 family. P2 receptors are divided into two types: ATP-gated nonselective cation channels (P2X) and G protein-coupled receptors (P2Y), the latter being activated by a broad range of purine and pyrimidine nucleotides (ATP, ADP, UTP, and UDP, among others). Purinergic signaling mechanisms are involved in numerous physiological events and pathophysiological conditions. Here, we address the growing body of evidence implicating purinergic signaling in male reproductive system functions. The life-long generation of fertile male germ cells is a highly complex, yet mechanistically poorly understood process. Given the relatively sparse innervation of the testis, spermatogenesis relies on both endocrine control and multi-directional paracrine communication. Therefore, a detailed understanding of such paracrine messengers, including ATP, is crucial to gain mechanistic insight into male reproduction..
Collapse
Affiliation(s)
- Nadine Mundt
- Department of Physiology, University of California, San Francisco, San Francisco, CA, United States
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
- Research Training Group 2416 MultiSenses – MultiScales, RWTH Aachen University, Aachen, Germany
- *Correspondence: Nadine Mundt,
| | - Lina Kenzler
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
- Research Training Group 2416 MultiSenses – MultiScales, RWTH Aachen University, Aachen, Germany
| |
Collapse
|
4
|
Belardin LB, Brochu K, Légaré C, Battistone MA, Breton S. Purinergic signaling in the male reproductive tract. Front Endocrinol (Lausanne) 2022; 13:1049511. [PMID: 36419764 PMCID: PMC9676935 DOI: 10.3389/fendo.2022.1049511] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 10/21/2022] [Indexed: 11/09/2022] Open
Abstract
Purinergic receptors are ubiquitously expressed throughout the body and they participate in the autocrine and paracrine regulation of cell function during normal physiological and pathophysiological conditions. Extracellular nucleotides activate several types of plasma membrane purinergic receptors that form three distinct families: P1 receptors are activated by adenosine, P2X receptors are activated by ATP, and P2Y receptors are activated by nucleotides including ATP, ADP, UTP, UDP, and UDP-glucose. These specific pharmacological fingerprints and the distinct intracellular signaling pathways they trigger govern a large variety of cellular responses in an organ-specific manner. As such, purinergic signaling regulates several physiological cell functions, including cell proliferation, differentiation and death, smooth muscle contraction, vasodilatation, and transepithelial transport of water, solute, and protons, as well as pathological pathways such as inflammation. While purinergic signaling was first discovered more than 90 years ago, we are just starting to understand how deleterious signals mediated through purinergic receptors may be involved in male infertility. A large fraction of male infertility remains unexplained illustrating our poor understanding of male reproductive health. Purinergic signaling plays a variety of physiological and pathophysiological roles in the male reproductive system, but our knowledge in this context remains limited. This review focuses on the distribution of purinergic receptors in the testis, epididymis, and vas deferens, and their role in the establishment and maintenance of male fertility.
Collapse
Affiliation(s)
- Larissa Berloffa Belardin
- Centre Hospitalier Universitaire de Québec - Research Centre and Department of Obstetrics, Gynecology and Reproduction, Faculty of Medicine, Université Laval, Québec, QC, Canada
| | - Kéliane Brochu
- Centre Hospitalier Universitaire de Québec - Research Centre and Department of Obstetrics, Gynecology and Reproduction, Faculty of Medicine, Université Laval, Québec, QC, Canada
| | - Christine Légaré
- Centre Hospitalier Universitaire de Québec - Research Centre and Department of Obstetrics, Gynecology and Reproduction, Faculty of Medicine, Université Laval, Québec, QC, Canada
| | - Maria Agustina Battistone
- Nephrology Division, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Sylvie Breton
- Centre Hospitalier Universitaire de Québec - Research Centre and Department of Obstetrics, Gynecology and Reproduction, Faculty of Medicine, Université Laval, Québec, QC, Canada
- *Correspondence: Sylvie Breton,
| |
Collapse
|
5
|
Missel A, Walenta L, Eubler K, Mundt N, Heikelä H, Pickl U, Trottmann M, Popper B, Poutanen M, Strauss L, Köhn FM, Kunz L, Spehr M, Mayerhofer A. Testicular adenosine acts as a pro-inflammatory molecule: role of testicular peritubular cells. Mol Hum Reprod 2021; 27:6276438. [PMID: 33993290 DOI: 10.1093/molehr/gaab037] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/27/2021] [Indexed: 12/13/2022] Open
Abstract
Extracellular ATP has been described to be involved in inflammatory cytokine production by human testicular peritubular cells (HTPCs). The ectonucleotidases ENTPD1 and NT5E degrade ATP and have been reported in rodent testicular peritubular cells. We hypothesized that if a similar situation exists in human testis, ATP metabolites may contribute to cytokine production. Indeed, ENTPD1 and NT5E were found in situ and in vitro in HTPCs. Malachite green assays confirmed enzyme activities in HTPCs. Pharmacological inhibition of ENTPD1 (by POM-1) significantly reduced pro-inflammatory cytokines evoked by ATP treatment, suggesting that metabolites of ATP, including adenosine, are likely involved. We focused on adenosine and detected three of the four known adenosine receptors in HTPCs. One, A2B, was also found in situ in peritubular cells of human testicular sections. The A2B agonist BAY60-6583 significantly elevated levels of IL6 and CXCL8, a result also obtained with adenosine and its analogue NECA. Results of siRNA-mediated A2B down-regulation support a role of this receptor. In mouse peritubular cells, in contrast to HTPCs, all four of the known adenosine receptors were detected; when challenged with adenosine, cytokine expression levels significantly increased. Organotypic short-term testis cultures yielded comparable results and indicate an overall pro-inflammatory action of adenosine in the mouse testis. If transferable to the in vivo situation, our results may implicate that interference with the generation of ATP metabolites or interference with adenosine receptors could reduce inflammatory events in the testis. These novel insights may provide new avenues for treatment of sterile inflammation in male subfertility and infertility.
Collapse
Affiliation(s)
- Annika Missel
- Cell Biology-Anatomy III, Faculty of Medicine, Biomedical Center (BMC), Ludwig-Maximilians-University Munich, Martinsried, Germany
| | - Lena Walenta
- Cell Biology-Anatomy III, Faculty of Medicine, Biomedical Center (BMC), Ludwig-Maximilians-University Munich, Martinsried, Germany
| | - Katja Eubler
- Cell Biology-Anatomy III, Faculty of Medicine, Biomedical Center (BMC), Ludwig-Maximilians-University Munich, Martinsried, Germany
| | - Nadine Mundt
- Institute of Biology II/Department of Chemosensation, RWTH Aachen University, Aachen, Germany.,Research Training Group 2416, MultiSenses-MultiScales, RWTH Aachen University, Aachen, Germany
| | - Hanna Heikelä
- Institute of Biomedicine, Research Center for Integrative Physiology and Pharmacology, Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | | | | | - Bastian Popper
- Biomedical Center (BMC), Core Facility Animal Models, Faculty of Medicine, Ludwig-Maximilians-University Munich, Martinsried, Germany
| | - Matti Poutanen
- Institute of Biomedicine, Research Center for Integrative Physiology and Pharmacology, Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | - Leena Strauss
- Institute of Biomedicine, Research Center for Integrative Physiology and Pharmacology, Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | | | - Lars Kunz
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-University Munich, Martinsried, Germany
| | - Marc Spehr
- Institute of Biology II/Department of Chemosensation, RWTH Aachen University, Aachen, Germany.,Research Training Group 2416, MultiSenses-MultiScales, RWTH Aachen University, Aachen, Germany
| | - Artur Mayerhofer
- Cell Biology-Anatomy III, Faculty of Medicine, Biomedical Center (BMC), Ludwig-Maximilians-University Munich, Martinsried, Germany
| |
Collapse
|
6
|
Ham J, Lim W, Song G. Flufenoxuron suppresses the proliferation of testicular cells by targeting mitochondria in mice. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2021; 173:104773. [PMID: 33771252 DOI: 10.1016/j.pestbp.2021.104773] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 12/29/2020] [Accepted: 12/30/2020] [Indexed: 06/12/2023]
Abstract
Flufenoxuron is a benzoylurea pesticide that is used to eradicate insects and acarids in the farmland. Even though it specifically works on target animals, the possibilities of its bioaccumulation and harmful effects on non-target animals cannot be denied. As the usage and application of pesticides increases, exposure to them also increases through ingestion of food residues, inhalation, or dermal contact. Pesticides could also be considered as endocrine disruptor chemicals; however, the reproductive toxicity and cellular mechanisms of flufenoxuron have not been identified. Our results indicate that flufenoxuron inhibits cellular proliferation and hampers calcium homeostasis, especially by targeting mitochondria. We also confirmed the induction of endoplasmic reticulum (ER) stress and ER-mitochondrial contact signaling. Using pharmacological inhibitors, we also observed that the mitogen-activated protein kinase and Akt signaling pathways were upregulated by flufenoxuron. Further, by oral administration of flufenoxuron (100 mg/kg/bw) to C57BL/6 male mice, we observed transcriptional changes in the testis-related genes. Collectively, we demonstrated that flufenoxuron inhibits cell proliferation and alters gene expression in mouse testis cells and induces testicular dysfunction in mice. These results indicate that flufenoxuron may be harmful to male reproduction and fertility in the early stages of pregnancy.
Collapse
Affiliation(s)
- Jiyeon Ham
- Institute of Animal Molecular Biotechnology and Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Whasun Lim
- Department of Food and Nutrition, Kookmin University, Seoul 02707, Republic of Korea.
| | - Gwonhwa Song
- Institute of Animal Molecular Biotechnology and Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea.
| |
Collapse
|
7
|
Fleck D, Kenzler L, Mundt N, Strauch M, Uesaka N, Moosmann R, Bruentgens F, Missel A, Mayerhofer A, Merhof D, Spehr J, Spehr M. ATP activation of peritubular cells drives testicular sperm transport. eLife 2021; 10:e62885. [PMID: 33502316 PMCID: PMC7840184 DOI: 10.7554/elife.62885] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 12/16/2020] [Indexed: 12/11/2022] Open
Abstract
Spermatogenesis, the complex process of male germ cell proliferation, differentiation, and maturation, is the basis of male fertility. In the seminiferous tubules of the testes, spermatozoa are constantly generated from spermatogonial stem cells through a stereotyped sequence of mitotic and meiotic divisions. The basic physiological principles, however, that control both maturation and luminal transport of the still immotile spermatozoa within the seminiferous tubules remain poorly, if at all, defined. Here, we show that coordinated contractions of smooth muscle-like testicular peritubular cells provide the propulsive force for luminal sperm transport toward the rete testis. Using a mouse model for in vivo imaging, we describe and quantify spontaneous tubular contractions and show a causal relationship between peritubular Ca2+ waves and peristaltic transport. Moreover, we identify P2 receptor-dependent purinergic signaling pathways as physiological triggers of tubular contractions both in vitro and in vivo. When challenged with extracellular ATP, transport of luminal content inside the seminiferous tubules displays stage-dependent directionality. We thus suggest that paracrine purinergic signaling coordinates peristaltic recurrent contractions of the mouse seminiferous tubules to propel immotile spermatozoa to the rete testis.
Collapse
Affiliation(s)
- David Fleck
- Department of Chemosensation, Institute for Biology II, RWTH Aachen UniversityAachenGermany
| | - Lina Kenzler
- Department of Chemosensation, Institute for Biology II, RWTH Aachen UniversityAachenGermany
| | - Nadine Mundt
- Department of Chemosensation, Institute for Biology II, RWTH Aachen UniversityAachenGermany
- Research Training Group 2416 MultiSenses – MultiScales, RWTH Aachen UniversityAachenGermany
| | - Martin Strauch
- Institute of Imaging and Computer Vision, RWTH Aachen UniversityAachenGermany
| | - Naofumi Uesaka
- Department of Chemosensation, Institute for Biology II, RWTH Aachen UniversityAachenGermany
- Department of Cognitive Neurobiology, Tokyo Medical and Dental UniversityTokyoJapan
| | - Robert Moosmann
- Department of Chemosensation, Institute for Biology II, RWTH Aachen UniversityAachenGermany
| | - Felicitas Bruentgens
- Department of Chemosensation, Institute for Biology II, RWTH Aachen UniversityAachenGermany
| | - Annika Missel
- Biomedical Center Munich (BMC), Cell Biology, Anatomy III, Ludwig-Maximilians-Universität MünchenPlanegg-MartinsriedGermany
| | - Artur Mayerhofer
- Biomedical Center Munich (BMC), Cell Biology, Anatomy III, Ludwig-Maximilians-Universität MünchenPlanegg-MartinsriedGermany
| | - Dorit Merhof
- Institute of Imaging and Computer Vision, RWTH Aachen UniversityAachenGermany
| | - Jennifer Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen UniversityAachenGermany
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen UniversityAachenGermany
- Research Training Group 2416 MultiSenses – MultiScales, RWTH Aachen UniversityAachenGermany
| |
Collapse
|
8
|
Synchronous Infra-Slow Oscillations Organize Ensembles of Accessory Olfactory Bulb Projection Neurons into Distinct Microcircuits. J Neurosci 2020; 40:4203-4218. [PMID: 32312886 PMCID: PMC7244196 DOI: 10.1523/jneurosci.2925-19.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/28/2020] [Accepted: 03/23/2020] [Indexed: 11/21/2022] Open
Abstract
The accessory olfactory system controls social and sexual behavior. In the mouse accessory olfactory bulb, the first central stage of information processing along the accessory olfactory pathway, projection neurons (mitral cells) display infra-slow oscillatory discharge with remarkable periodicity. The physiological mechanisms that underlie this default output state, however, remain controversial. Moreover, whether such rhythmic infra-slow activity patterns exist in awake behaving mice and whether such activity reflects the functional organization of the accessory olfactory bulb circuitry remain unclear. Here, we hypothesize that mitral cell ensembles form synchronized microcircuits that subdivide the accessory olfactory bulb into segregated functional clusters. We use a miniature microscope to image the Ca2+ dynamics within the apical dendritic compartments of large mitral cell ensembles in vivo. We show that infra-slow periodic patterns of concerted neural activity, indeed, reflect the idle state of accessory olfactory bulb output in awake male and female mice. Ca2+ activity profiles are distinct and glomerulus-specific. Confocal time-lapse imaging in acute slices reveals that groups of mitral cells assemble into microcircuits that exhibit correlated Ca2+ signals. Moreover, electrophysiological profiling of synaptic connectivity indicates functional coupling between mitral cells. Our results suggest that both intrinsically rhythmogenic neurons and neurons entrained by fast synaptic drive are key elements in organizing the accessory olfactory bulb into functional microcircuits, each characterized by a distinct default pattern of infra-slow rhythmicity. SIGNIFICANCE STATEMENT Information processing in the accessory olfactory bulb (AOB) plays a central role in conspecific chemosensory communication. Surprisingly, many basic physiological principles that underlie neuronal signaling in the AOB remain elusive. Here, we show that AOB projection neurons (mitral cells) form parallel synchronized ensembles both in vitro and in vivo. Infra-slow synchronous oscillatory activity within AOB microcircuits thus adds a new dimension to chemosensory coding along the accessory olfactory pathway.
Collapse
|
9
|
Mohrhardt J, Nagel M, Fleck D, Ben-Shaul Y, Spehr M. Signal Detection and Coding in the Accessory Olfactory System. Chem Senses 2019; 43:667-695. [PMID: 30256909 PMCID: PMC6211456 DOI: 10.1093/chemse/bjy061] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In many mammalian species, the accessory olfactory system plays a central role in guiding behavioral and physiological responses to social and reproductive interactions. Because of its relatively compact structure and its direct access to amygdalar and hypothalamic nuclei, the accessory olfactory pathway provides an ideal system to study sensory control of complex mammalian behavior. During the last several years, many studies employing molecular, behavioral, and physiological approaches have significantly expanded and enhanced our understanding of this system. The purpose of the current review is to integrate older and newer studies to present an updated and comprehensive picture of vomeronasal signaling and coding with an emphasis on early accessory olfactory system processing stages. These include vomeronasal sensory neurons in the vomeronasal organ, and the circuitry of the accessory olfactory bulb. Because the overwhelming majority of studies on accessory olfactory system function employ rodents, this review is largely focused on this phylogenetic order, and on mice in particular. Taken together, the emerging view from both older literature and more recent studies is that the molecular, cellular, and circuit properties of chemosensory signaling along the accessory olfactory pathway are in many ways unique. Yet, it has also become evident that, like the main olfactory system, the accessory olfactory system also has the capacity for adaptive learning, experience, and state-dependent plasticity. In addition to describing what is currently known about accessory olfactory system function and physiology, we highlight what we believe are important gaps in our knowledge, which thus define exciting directions for future investigation.
Collapse
Affiliation(s)
- Julia Mohrhardt
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - Maximilian Nagel
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - David Fleck
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - Yoram Ben-Shaul
- Department of Medical Neurobiology, School of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| |
Collapse
|
10
|
Sensory Adaptation to Chemical Cues by Vomeronasal Sensory Neurons. eNeuro 2018; 5:eN-NWR-0223-18. [PMID: 30105301 PMCID: PMC6088365 DOI: 10.1523/eneuro.0223-18.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/13/2018] [Accepted: 07/18/2018] [Indexed: 01/03/2023] Open
Abstract
Sensory adaptation is a source of experience-dependent feedback that impacts responses to environmental cues. In the mammalian main olfactory system (MOS), adaptation influences sensory coding at its earliest processing stages. Sensory adaptation in the accessory olfactory system (AOS) remains incompletely explored, leaving many aspects of the phenomenon unclear. We investigated sensory adaptation in vomeronasal sensory neurons (VSNs) using a combination of in situ Ca2+ imaging and electrophysiology. Parallel studies revealed prominent short-term sensory adaptation in VSNs upon repeated stimulation with mouse urine and monomolecular bile acid ligands at interstimulus intervals (ISIs) less than 30 s. In such conditions, Ca2+ signals and spike rates were often reduced by more than 50%, leading to dramatically reduced chemosensory sensitivity. Short-term adaptation was reversible over the course of minutes. Population Ca2+ imaging experiments revealed the presence of a slower form of VSN adaptation that accumulated over dozens of stimulus presentations delivered over tens of minutes. Most VSNs showed strong adaptation, but in a substantial VSN subpopulation adaptation was diminished or absent. Investigation of same- and opposite-sex urine responses in male and female VSNs revealed that adaptation to same-sex cues occurred at ISIs up to 180 s, conditions that did not induce adaptation to opposite-sex cues. This result suggests that VSN sensory adaptation can be modulated by sensory experience. These studies comprehensively establish the presence of VSN sensory adaptation and provide a foundation for future inquiries into the molecular and cellular mechanisms of this phenomenon and its impact on mammalian behavior.
Collapse
|
11
|
Lu W, Gómez NM, Lim JC, Guha S, O'Brien-Jenkins A, Coffey EE, Campagno KE, McCaughey SA, Laties AM, Carlsson LG, Mitchell CH. The P2Y 12 Receptor Antagonist Ticagrelor Reduces Lysosomal pH and Autofluorescence in Retinal Pigmented Epithelial Cells From the ABCA4 -/- Mouse Model of Retinal Degeneration. Front Pharmacol 2018; 9:242. [PMID: 29725296 PMCID: PMC5917064 DOI: 10.3389/fphar.2018.00242] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 03/05/2018] [Indexed: 11/13/2022] Open
Abstract
The accumulation of partially degraded lipid waste in lysosomal-related organelles may contribute to pathology in many aging diseases. The presence of these lipofuscin granules is particularly evident in the autofluorescent lysosome-associated organelles of the retinal pigmented epithelial (RPE) cells, and may be related to early stages of age-related macular degeneration. While lysosomal enzymes degrade material optimally at acidic pH levels, lysosomal pH is elevated in RPE cells from the ABCA4-/- mouse model of Stargardt's disease, an early onset retinal degeneration. Lowering lysosomal pH through cAMP-dependent pathways decreases accumulation of autofluorescent material in RPE cells in vitro, but identification of an appropriate receptor is crucial for manipulating this pathway in vivo. As the P2Y12 receptor for ADP is coupled to the inhibitory Gi protein, we asked whether blocking the P2Y12 receptor with ticagrelor could restore lysosomal acidity and reduce autofluorescence in compromised RPE cells from ABCA4-/- mice. Oral delivery of ticagrelor giving rise to clinically relevant exposure lowered lysosomal pH in these RPE cells. Ticagrelor also partially reduced autofluorescence in the RPE cells of ABCA4-/- mice. In vitro studies in ARPE-19 cells using more specific antagonists AR-C69931 and AR-C66096 confirmed the importance of the P2Y12 receptor for lowering lysosomal pH and reducing autofluorescence. These observations identify P2Y12 receptor blockade as a potential target to lower lysosomal pH and clear lysosomal waste in RPE cells.
Collapse
Affiliation(s)
- Wennan Lu
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Néstor M Gómez
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Jason C Lim
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Sonia Guha
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States.,Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Ann O'Brien-Jenkins
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Erin E Coffey
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Keith E Campagno
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Stuart A McCaughey
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Alan M Laties
- Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Leif G Carlsson
- Department of Bioscience Heart Failure, Cardiovascular, Renal and Metabolic Diseases, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Claire H Mitchell
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States.,Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, United States.,Department of Physiology, University of Pennsylvania, Philadelphia, PA, United States
| |
Collapse
|
12
|
Tsai T, Veitinger S, Peek I, Busse D, Eckardt J, Vladimirova D, Jovancevic N, Wojcik S, Gisselmann G, Altmüller J, Ständer S, Luger T, Paus R, Cheret J, Hatt H. Two olfactory receptors-OR2A4/7 and OR51B5-differentially affect epidermal proliferation and differentiation. Exp Dermatol 2018; 26:58-65. [PMID: 27315375 DOI: 10.1111/exd.13132] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/16/2016] [Indexed: 12/20/2022]
Abstract
Olfactory receptors (ORs), which belong to the G-protein coupled receptor family, are expressed in various human tissues, including skin. Cells in non-olfactory tissues tend to express more than one individual OR gene, but function and interaction of two or more ORs in the same cell type has only been marginally analysed. Here, we revealed OR2A4/7 and OR51B5 as two new ORs in human skin cells and identified cyclohexyl salicylate and isononyl alcohol as agonists of these receptors. In cultured human keratinocytes, both odorants induce strong Ca2+ signals that are mediated by OR2A4/7 and OR51B5, as demonstrated by the receptor knockdown experiments. Activation of corresponding receptors induces a cAMP-dependent pathway. Localization studies and functional characterization of both receptors revealed several differences. OR2A4/7 is expressed in suprabasal keratinocytes and basal melanocytes of the epidermis and influences cytokinesis, cell proliferation, phosphorylation of AKT and Chk-2 and secretion of IL-1. In contrast, OR51B5 is exclusively expressed in suprabasal keratinocytes, supports cell migration and regeneration of keratinocyte monolayers, influences Hsp27, AMPK1 and p38MAPK phosphorylation and interestingly, IL-6 secretion. These findings underline that different ORs perform diverse functions in cutaneous cells, and thus offering an approach for the modulated treatment of skin diseases and wound repair.
Collapse
Affiliation(s)
- Teresa Tsai
- Department of Cell Physiology, Ruhr-University Bochum, Bochum, Germany
| | - Sophie Veitinger
- Department of Cell Physiology, Ruhr-University Bochum, Bochum, Germany
| | - Irina Peek
- Department of Cell Physiology, Ruhr-University Bochum, Bochum, Germany
| | - Daniela Busse
- Department of Cell Physiology, Ruhr-University Bochum, Bochum, Germany
| | - Josephine Eckardt
- Department of Cell Physiology, Ruhr-University Bochum, Bochum, Germany
| | | | | | - Sebastian Wojcik
- Department of Cell Physiology, Ruhr-University Bochum, Bochum, Germany
| | - Günter Gisselmann
- Department of Cell Physiology, Ruhr-University Bochum, Bochum, Germany
| | | | - Sonja Ständer
- Department of Dermatology, Center for Chronic Pruritus, University Hospital Münster, Münster, Germany
| | | | - Ralf Paus
- Department of Dermatology, Laboratory for Hair Research and Regenerative Medicine, University Hospital of Münster, Münster, Germany
| | - Jeremy Cheret
- Department of Dermatology, Laboratory for Hair Research and Regenerative Medicine, University Hospital of Münster, Münster, Germany
| | - Hanns Hatt
- Department of Cell Physiology, Ruhr-University Bochum, Bochum, Germany
| |
Collapse
|
13
|
Pelz T, Drose DR, Fleck D, Henkel B, Ackels T, Spehr M, Neuhaus EM. An ancestral TMEM16 homolog from Dictyostelium discoideum forms a scramblase. PLoS One 2018; 13:e0191219. [PMID: 29444117 PMCID: PMC5812556 DOI: 10.1371/journal.pone.0191219] [Citation(s) in RCA: 13] [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: 04/18/2017] [Accepted: 12/29/2017] [Indexed: 01/11/2023] Open
Abstract
TMEM16 proteins are a recently identified protein family comprising Ca2+-activated Cl- channels that generate outwardly rectifying ionic currents in response to intracellular Ca2+ elevations. Some TMEM16 family members, such as TMEM16F/ANO6 are also essential for Ca2+-dependent phospholipid scrambling. TMEM16-like genes are present in the genomes of most eukaryotic species, the function(s) of TMEM16 family members from evolutionary ancient eukaryotes is not completely clear. Here, we provide insight into the evolution of these TMEM16 proteins by similarity searches for ancestral sequences. All eukaryotic genomes contain TMEM16 homologs, but only vertebrates have the full repertoire of ten distinct subtypes. TMEM16 homologs studied so far belong to the opisthokont branch of the phylogenetic tree, which includes the animal and fungal kingdoms. An organism outside this group is Dictyostelium discoideum, a representative of the amoebozoa group that diverged from the metazoa before fungi. We here functionally investigated the TMEM16 family member from Dictyostelium discoideum. When recombinantly expressed in HEK293 cells, DdTMEM16 induces phospholipid scrambling. However, in several electrophysiological experiments we did not find evidence for a Ca2+-activated Cl- channel function of DdTMEM16.
Collapse
Affiliation(s)
- Thomas Pelz
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Daniela R. Drose
- Department of Chemosensation, Institute for Biology II, RWTH-Aachen University, Aachen, Germany
| | - David Fleck
- Department of Chemosensation, Institute for Biology II, RWTH-Aachen University, Aachen, Germany
| | - Bastian Henkel
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Tobias Ackels
- Department of Chemosensation, Institute for Biology II, RWTH-Aachen University, Aachen, Germany
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH-Aachen University, Aachen, Germany
| | - Eva M. Neuhaus
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Berlin, Germany
- * E-mail:
| |
Collapse
|
14
|
ATP-mediated Events in Peritubular Cells Contribute to Sterile Testicular Inflammation. Sci Rep 2018; 8:1431. [PMID: 29362497 PMCID: PMC5780482 DOI: 10.1038/s41598-018-19624-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 01/03/2018] [Indexed: 12/19/2022] Open
Abstract
Peritubular myoid cells, which form the walls of seminiferous tubules in the testis, are functionally unexplored. While they transport sperm and contribute to the spermatogonial stem cell niche, specifically their emerging role in the immune surveillance of the testis and in male infertility remains to be studied. Recently, cytokine production and activation of Toll-like receptors (TLRs) were uncovered in cultured peritubular cells. We now show that human peritubular cells express purinergic receptors P2RX4 and P2RX7, which are functionally linked to TLRs, with P2RX4 being the prevalent ATP-gated ion channel. Subsequent ATP treatment of cultured peritubular cells resulted in up-regulated (pro-)inflammatory cytokine expression and secretion, while characteristic peritubular proteins, that is smooth muscle cell markers and extracellular matrix molecules, decreased. These findings indicate that extracellular ATP may act as danger molecule on peritubular cells, able to promote inflammatory responses in the testicular environment.
Collapse
|
15
|
Membrane permeation of arginine-rich cell-penetrating peptides independent of transmembrane potential as a function of lipid composition and membrane fluidity. J Control Release 2017; 256:68-78. [DOI: 10.1016/j.jconrel.2017.04.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Accepted: 04/10/2017] [Indexed: 11/19/2022]
|
16
|
Lapel M, Weston P, Strassheim D, Karoor V, Burns N, Lyubchenko T, Paucek P, Stenmark KR, Gerasimovskaya EV. Glycolysis and oxidative phosphorylation are essential for purinergic receptor-mediated angiogenic responses in vasa vasorum endothelial cells. Am J Physiol Cell Physiol 2016; 312:C56-C70. [PMID: 27856430 PMCID: PMC5283894 DOI: 10.1152/ajpcell.00250.2016] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 11/03/2016] [Indexed: 11/24/2022]
Abstract
Angiogenesis is an energy-demanding process; however, the role of cellular energy pathways and their regulation by extracellular stimuli, especially extracellular nucleotides, remain largely unexplored. Using metabolic inhibitors of glycolysis (2-deoxyglucose) and oxidative phosphorylation (OXPHOS) (oligomycin, rotenone, and FCCP), we demonstrate that glycolysis and OXPHOS are both essential for angiogenic responses of vasa vasorum endothelial cell (VVEC). Treatment with P2R agonists, ATP, and 2-methylthioadenosine diphosphate trisodium salt (MeSADP), but not P1 receptor agonist, adenosine, increased glycolytic activity in VVEC (measured by extracellular acidification rate and lactate production). Stimulation of glycolysis was accompanied by increased levels of phospho-phosphofructokinase B3, hexokinase (HK), and GLUT-1, but not lactate dehydrogenase. Moreover, extracellular ATP and MeSADP, and to a lesser extent adenosine, increased basal and maximal oxygen consumption rates in VVEC. These effects were potentiated when the cells were cultured in 20 mM galactose and 5 mM glucose compared with 25 mM glucose. Treatment with P2R agonists decreased phosphorylation of pyruvate dehydrogenase (PDH)-E1α and increased succinate dehydrogenase (SDH), cytochrome oxidase IV, and β-subunit of F1F0 ATP synthase expression. In addition, P2R stimulation transiently elevated mitochondrial Ca2+ concentration, implying involvement of mitochondria in VVEC angiogenic activation. We also demonstrated a critical role of phosphatidylinositol 3-kinase and Akt pathways in lactate production, PDH-E1α phosphorylation, and the expression of HK, SDH, and GLUT-1 in ATP-stimulated VVEC. Together, our findings suggest that purinergic and metabolic regulation of VVEC energy pathways is essential for VV angiogenesis and may contribute to pathologic vascular remodeling in pulmonary hypertension.
Collapse
Affiliation(s)
- Martin Lapel
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado
| | - Philip Weston
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado
| | - Derek Strassheim
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado
| | - Vijaya Karoor
- Department of Medicine, University of Colorado Denver, Aurora, Colorado; and
| | - Nana Burns
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado
| | - Taras Lyubchenko
- Department of Medicine, University of Colorado Denver, Aurora, Colorado; and
| | - Petr Paucek
- Department of Pharmacology, University of Colorado Denver, Aurora, Colorado
| | - Kurt R Stenmark
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado
| | | |
Collapse
|
17
|
Ackels T, Drose DR, Spehr M. In-depth Physiological Analysis of Defined Cell Populations in Acute Tissue Slices of the Mouse Vomeronasal Organ. J Vis Exp 2016. [PMID: 27684435 DOI: 10.3791/54517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In most mammals, the vomeronasal organ (VNO) is a chemosensory structure that detects both hetero- and conspecific social cues. Vomeronasal sensory neurons (VSNs) express a specific type of G protein-coupled receptor (GPCR) from at least three different chemoreceptor gene families allowing sensitive and specific detection of chemosensory cues. These families comprise the V1r and V2r gene families as well as the formyl peptide receptor (FPR)-related sequence (Fpr-rs) family of putative chemoreceptor genes. In order to understand the physiology of vomeronasal receptor-ligand interactions and downstream signaling, it is essential to identify the biophysical properties inherent to each specific class of VSNs. The physiological approach described here allows identification and in-depth analysis of a defined population of sensory neurons using a transgenic mouse line (Fpr-rs3-i-Venus). The use of this protocol, however, is not restricted to this specific line and thus can easily be extended to other genetically modified lines or wild type animals.
Collapse
Affiliation(s)
- Tobias Ackels
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University; Mill Hill Laboratory, The Francis Crick Institute;
| | - Daniela R Drose
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University
| |
Collapse
|
18
|
Fleck D, Mundt N, Bruentgens F, Geilenkirchen P, Machado PA, Veitinger T, Veitinger S, Lipartowski SM, Engelhardt CH, Oldiges M, Spehr J, Spehr M. Distinct purinergic signaling pathways in prepubescent mouse spermatogonia. J Gen Physiol 2016; 148:253-71. [PMID: 27574293 PMCID: PMC5004339 DOI: 10.1085/jgp.201611636] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 07/22/2016] [Indexed: 01/24/2023] Open
Abstract
Spermatogenesis ranks among the most complex, yet least understood, developmental processes. The physiological principles that control male germ cell development in mammals are notoriously difficult to unravel, given the intricate anatomy and complex endo- and paracrinology of the testis. Accordingly, we lack a conceptual understanding of the basic signaling mechanisms within the testis, which control the seminiferous epithelial cycle and thus govern spermatogenesis. Here, we address paracrine signal transduction in undifferentiated male germ cells from an electrophysiological perspective. We identify distinct purinergic signaling pathways in prepubescent mouse spermatogonia, both in vitro and in situ. ATP-a dynamic, widespread, and evolutionary conserved mediator of cell to cell communication in various developmental contexts-activates at least two different spermatogonial purinoceptor isoforms. Both receptors operate within nonoverlapping stimulus concentration ranges, display distinct response kinetics and, in the juvenile seminiferous cord, are uniquely expressed in spermatogonia. We further find that spermatogonia express Ca(2+)-activated large-conductance K(+) channels that appear to function as a safeguard against prolonged ATP-dependent depolarization. Quantitative purine measurements additionally suggest testicular ATP-induced ATP release, a mechanism that could increase the paracrine radius of initially localized signaling events. Moreover, we establish a novel seminiferous tubule slice preparation that allows targeted electrophysiological recordings from identified testicular cell types in an intact epithelial environment. This unique approach not only confirms our in vitro findings, but also supports the notion of purinergic signaling during the early stages of spermatogenesis.
Collapse
Affiliation(s)
- David Fleck
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, D-52074 Aachen, Germany
| | - Nadine Mundt
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, D-52074 Aachen, Germany
| | - Felicitas Bruentgens
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, D-52074 Aachen, Germany
| | - Petra Geilenkirchen
- Institute of Bio- and Geosciences (IBG), IBG-1: Biotechnology, Research Center Jülich, D-52425 Jülich, Germany
| | - Patricia A Machado
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, D-52074 Aachen, Germany
| | - Thomas Veitinger
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, D-52074 Aachen, Germany
| | - Sophie Veitinger
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, D-52074 Aachen, Germany
| | - Susanne M Lipartowski
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, D-52074 Aachen, Germany
| | - Corinna H Engelhardt
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, D-52074 Aachen, Germany
| | - Marco Oldiges
- Institute of Bio- and Geosciences (IBG), IBG-1: Biotechnology, Research Center Jülich, D-52425 Jülich, Germany
| | - Jennifer Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, D-52074 Aachen, Germany
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, D-52074 Aachen, Germany
| |
Collapse
|
19
|
Interdependent Conductances Drive Infraslow Intrinsic Rhythmogenesis in a Subset of Accessory Olfactory Bulb Projection Neurons. J Neurosci 2016; 36:3127-44. [PMID: 26985025 DOI: 10.1523/jneurosci.2520-15.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED The accessory olfactory system controls social and sexual behavior. However, key aspects of sensory signaling along the accessory olfactory pathway remain largely unknown. Here, we investigate patterns of spontaneous neuronal activity in mouse accessory olfactory bulb mitral cells, the direct neural link between vomeronasal sensory input and limbic output. Both in vitro and in vivo, we identify a subpopulation of mitral cells that exhibit slow stereotypical rhythmic discharge. In intrinsically rhythmogenic neurons, these periodic activity patterns are maintained in absence of fast synaptic drive. The physiological mechanism underlying mitral cell autorhythmicity involves cyclic activation of three interdependent ionic conductances: subthreshold persistent Na(+) current, R-type Ca(2+) current, and Ca(2+)-activated big conductance K(+) current. Together, the interplay of these distinct conductances triggers infraslow intrinsic oscillations with remarkable periodicity, a default output state likely to affect sensory processing in limbic circuits. SIGNIFICANCE STATEMENT We show for the first time that some rodent accessory olfactory bulb mitral cells-the direct link between vomeronasal sensory input and limbic output-are intrinsically rhythmogenic. Driven by ≥ 3 distinct interdependent ionic conductances, infraslow intrinsic oscillations show remarkable periodicity both in vitro and in vivo. As a novel default state, infraslow autorhythmicity is likely to affect limbic processing of pheromonal information.
Collapse
|
20
|
Gamper I, Fleck D, Barlin M, Spehr M, El Sayad S, Kleine H, Maxeiner S, Schalla C, Aydin G, Hoss M, Litchfield DW, Lüscher B, Zenke M, Sechi A. GAR22β regulates cell migration, sperm motility, and axoneme structure. Mol Biol Cell 2015; 27:277-94. [PMID: 26564797 PMCID: PMC4713131 DOI: 10.1091/mbc.e15-06-0426] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 11/06/2015] [Indexed: 01/24/2023] Open
Abstract
Spatiotemporal cytoskeleton remodeling is crucial for several biological processes. GAR22β interacts with EB1 via a novel noncanonical amino acid sequence and is pivotal for cell motility and focal adhesion turnover. GAR22β is also crucial for generation, motility, and ultrastructural organization of spermatozoa. Spatiotemporal cytoskeleton remodeling is pivotal for cell adhesion and migration. Here we investigated the function of Gas2-related protein on chromosome 22 (GAR22β), a poorly characterized protein that interacts with actin and microtubules. Primary and immortalized GAR22β−/− Sertoli cells moved faster than wild-type cells. In addition, GAR22β−/− cells showed a more prominent focal adhesion turnover. GAR22β overexpression or its reexpression in GAR22β−/− cells reduced cell motility and focal adhesion turnover. GAR22β–actin interaction was stronger than GAR22β–microtubule interaction, resulting in GAR22β localization and dynamics that mirrored those of the actin cytoskeleton. Mechanistically, GAR22β interacted with the regulator of microtubule dynamics end-binding protein 1 (EB1) via a novel noncanonical amino acid sequence, and this GAR22β–EB1 interaction was required for the ability of GAR22β to modulate cell motility. We found that GAR22β is highly expressed in mouse testes, and its absence resulted in reduced spermatozoa generation, lower actin levels in testes, and impaired motility and ultrastructural disorganization of spermatozoa. Collectively our findings identify GAR22β as a novel regulator of cell adhesion and migration and provide a foundation for understanding the molecular basis of diverse cytoskeleton-dependent processes.
Collapse
Affiliation(s)
- Ivonne Gamper
- Institute for Biomedical Engineering, Department of Cell Biology, RWTH Aachen University Medical School, D-52074 Aachen, Germany Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, D-52074 Aachen, Germany
| | - David Fleck
- Institute for Biology II, Department of Chemosensation, RWTH Aachen University, D-52074 Aachen, Germany
| | - Meltem Barlin
- Institute for Biomedical Engineering, Department of Cell Biology, RWTH Aachen University Medical School, D-52074 Aachen, Germany Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, D-52074 Aachen, Germany
| | - Marc Spehr
- Institute for Biology II, Department of Chemosensation, RWTH Aachen University, D-52074 Aachen, Germany
| | - Sara El Sayad
- Institute for Biomedical Engineering, Department of Cell Biology, RWTH Aachen University Medical School, D-52074 Aachen, Germany Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, D-52074 Aachen, Germany
| | - Henning Kleine
- Institute of Biochemistry and Molecular Biology, Uniklinik RWTH Aachen, D-52074 Aachen, Germany
| | - Sebastian Maxeiner
- Institute for Biomedical Engineering, Department of Cell Biology, RWTH Aachen University Medical School, D-52074 Aachen, Germany Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, D-52074 Aachen, Germany
| | - Carmen Schalla
- Institute for Biomedical Engineering, Department of Cell Biology, RWTH Aachen University Medical School, D-52074 Aachen, Germany Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, D-52074 Aachen, Germany
| | - Gülcan Aydin
- Institute for Biomedical Engineering, Department of Cell Biology, RWTH Aachen University Medical School, D-52074 Aachen, Germany Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, D-52074 Aachen, Germany
| | - Mareike Hoss
- Electron Microscopy Facility, Uniklinik RWTH Aachen, D-52074 Aachen, Germany
| | - David W Litchfield
- Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Bernhard Lüscher
- Institute of Biochemistry and Molecular Biology, Uniklinik RWTH Aachen, D-52074 Aachen, Germany
| | - Martin Zenke
- Institute for Biomedical Engineering, Department of Cell Biology, RWTH Aachen University Medical School, D-52074 Aachen, Germany Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, D-52074 Aachen, Germany
| | - Antonio Sechi
- Institute for Biomedical Engineering, Department of Cell Biology, RWTH Aachen University Medical School, D-52074 Aachen, Germany Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, D-52074 Aachen, Germany
| |
Collapse
|
21
|
Oberland S, Ackels T, Gaab S, Pelz T, Spehr J, Spehr M, Neuhaus EM. CD36 is involved in oleic acid detection by the murine olfactory system. Front Cell Neurosci 2015; 9:366. [PMID: 26441537 PMCID: PMC4584952 DOI: 10.3389/fncel.2015.00366] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/03/2015] [Indexed: 11/29/2022] Open
Abstract
Olfactory signals influence food intake in a variety of species. To maximize the chances of finding a source of calories, an animal’s preference for fatty foods and triglycerides already becomes apparent during olfactory food search behavior. However, the molecular identity of both receptors and ligands mediating olfactory-dependent fatty acid recognition are, so far, undescribed. We here describe that a subset of olfactory sensory neurons expresses the fatty acid receptor CD36 and demonstrate a receptor-like localization of CD36 in olfactory cilia by STED microscopy. CD36-positive olfactory neurons share olfaction-specific transduction elements and project to numerous glomeruli in the ventral olfactory bulb. In accordance with the described roles of CD36 as fatty acid receptor or co-receptor in other sensory systems, the number of olfactory neurons responding to oleic acid, a major milk component, in Ca2+ imaging experiments is drastically reduced in young CD36 knock-out mice. Strikingly, we also observe marked age-dependent changes in CD36 localization, which is prominently present in the ciliary compartment only during the suckling period. Our results support the involvement of CD36 in fatty acid detection by the mammalian olfactory system.
Collapse
Affiliation(s)
- Sonja Oberland
- Pharmacology and Toxicology, University Hospital Jena, Friedrich-Schiller-University Jena Jena, Germany ; Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin Berlin, Germany ; Freie Universität-Berlin, Fachbereich Biologie, Chemie und Pharmazie Berlin, Germany
| | - Tobias Ackels
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University Aachen, Germany
| | - Stefanie Gaab
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin Berlin, Germany
| | - Thomas Pelz
- Pharmacology and Toxicology, University Hospital Jena, Friedrich-Schiller-University Jena Jena, Germany ; Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin Berlin, Germany
| | - Jennifer Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University Aachen, Germany
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University Aachen, Germany
| | - Eva M Neuhaus
- Pharmacology and Toxicology, University Hospital Jena, Friedrich-Schiller-University Jena Jena, Germany ; Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin Berlin, Germany
| |
Collapse
|
22
|
Abstract
The mouse vomeronasal organ (VNO) plays a critical role in semiochemical detection and social communication. Vomeronasal stimuli are typically secreted in various body fluids. Following direct contact with urine deposits or other secretions, a peristaltic vascular pump mediates fluid entry into the recipient's VNO. Therefore, while vomeronasal sensory neurons (VSNs) sample various stimulatory semiochemicals dissolved in the intraluminal mucus, they might also be affected by the general physicochemical properties of the "solvent." Here, we report cycle stage-correlated variations in urinary pH among female mice. Estrus-specific pH decline is observed exclusively in urine samples from sexually experienced females. Moreover, patch-clamp recordings in acute VNO slices reveal that mouse VSNs reliably detect extracellular acidosis. Acid-evoked responses share the biophysical and pharmacological hallmarks of the hyperpolarization-activated current Ih. Mechanistically, VSN acid sensitivity depends on a pH-induced shift in the voltage-dependence of Ih activation that causes the opening of HCN channels at rest, thereby increasing VSN excitability. Together, our results identify extracellular acidification as a potent activator of vomeronasal Ih and suggest HCN channel-dependent vomeronasal gain control of social chemosignaling. Our data thus reveal a potential mechanistic basis for stimulus pH detection in rodent chemosensory communication.
Collapse
|
23
|
Abstract
Adenosine-5'-triphosphate is released by neuroendocrine, endocrine, and other cell types and acts as an extracellular agonist for ligand-gated P2X cationic channels and G protein-coupled P2Y receptors in numerous organs and tissues, including the endocrine system. The breakdown of ATP by ectonucleotidases not only terminates its extracellular messenger functions, but also provides a pathway for the generation of two additional agonists: adenosine 5'-diphosphate, acting via some P2Y receptors, and adenosine, a native agonist for G protein-coupled adenosine receptors, also expressed in the endocrine system. This article provides a review of purinergic signaling pathways in the hypothalamic magnocellular neurosecretory cells and neurohypophysis, hypothalamic parvocellular neuroendocrine system, adenohypophysis, and effector glands organized in five axes: hypothalamic-pituitary-gonadal, hypothalamic-pituitary-thyroid, hypothalamic-pituitary-adrenal, hypothalamic-pituitary-growth hormone, and hypothalamic-pituitary-prolactin. We attempted to summarize current knowledge of purinergic receptor subtypes expressed in the endocrine system, including their roles in intracellular signaling, hormone secretion, and other cell functions. We also briefly review the release mechanism for adenosine-5'-triphosphate by neuroendocrine, endocrine and surrounding cells, the enzymes involved in adenosine-5'-triphosphate hydrolysis to adenosine-5'-diphosphate and adenosine, and the relevance of this pathway for sequential activation of receptors and termination of signaling.
Collapse
|
24
|
Ackels T, von der Weid B, Rodriguez I, Spehr M. Physiological characterization of formyl peptide receptor expressing cells in the mouse vomeronasal organ. Front Neuroanat 2014; 8:134. [PMID: 25484858 PMCID: PMC4240171 DOI: 10.3389/fnana.2014.00134] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 11/01/2014] [Indexed: 12/14/2022] Open
Abstract
The mouse vomeronasal organ (VNO) is a chemosensory structure that detects both hetero- and conspecific social cues. Based on largely monogenic expression of either type 1 or 2 vomeronasal receptors (V1Rs/V2Rs) or members of the formyl peptide receptor (FPR) family, the vomeronasal sensory epithelium harbors at least three neuronal subpopulations. While various neurophysiological properties of both V1R- and V2R-expressing neurons have been described using genetically engineered mouse models, the basic biophysical characteristics of the more recently identified FPR-expressing vomeronasal neurons have not been studied. Here, we employ a transgenic mouse strain that coexpresses an enhanced variant of yellow fluorescent protein together with FPR-rs3 allowing to identify and analyze FPR-rs3-expressing neurons in acute VNO tissue slices. Single neuron electrophysiological recordings allow comparative characterization of the biophysical properties inherent to a prototypical member of the FPR-expressing subpopulation of VNO neurons. In this study, we provide an in-depth analysis of both passive and active membrane properties, including detailed characterization of several types of voltage-activated conductances and action potential discharge patterns, in fluorescently labeled vs. unmarked vomeronasal neurons. Our results reveal striking similarities in the basic (electro) physiological architecture of both transgene-expressing and non-expressing neurons, confirming the suitability of this genetically engineered mouse model for future studies addressing more specialized issues in vomeronasal FPR neurobiology.
Collapse
Affiliation(s)
- Tobias Ackels
- Department of Chemosensation, RWTH Aachen University Aachen, Germany
| | - Benoît von der Weid
- Department of Genetics and Evolution, University of Geneva Geneva, Switzerland
| | - Ivan Rodriguez
- Department of Genetics and Evolution, University of Geneva Geneva, Switzerland
| | - Marc Spehr
- Department of Chemosensation, RWTH Aachen University Aachen, Germany
| |
Collapse
|
25
|
Kaur AW, Ackels T, Kuo TH, Cichy A, Dey S, Hays C, Kateri M, Logan DW, Marton TF, Spehr M, Stowers L. Murine pheromone proteins constitute a context-dependent combinatorial code governing multiple social behaviors. Cell 2014; 157:676-88. [PMID: 24766811 DOI: 10.1016/j.cell.2014.02.025] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 01/07/2014] [Accepted: 02/05/2014] [Indexed: 10/25/2022]
Abstract
During social interactions, an individual's behavior is largely governed by the subset of signals emitted by others. Discrimination of "self" from "other" regulates the territorial urine countermarking behavior of mice. To identify the cues for this social discrimination and understand how they are interpreted, we designed an olfactory-dependent countermarking assay. We find major urinary proteins (MUPs) sufficient to elicit countermarking, and unlike other vomeronasal ligands that are detected by specifically tuned sensory neurons, MUPs are detected by a combinatorial strategy. A chemosensory signature of "self" that modulates behavior is developed via experience through exposure to a repertoire of MUPs. In contrast, aggression can be elicited by MUPs in an experience-independent but context-dependent manner. These findings reveal that individually emitted chemical cues can be interpreted based on their combinatorial permutation and relative ratios, and they can transmit both fixed and learned information to promote multiple behaviors.
Collapse
Affiliation(s)
- Angeldeep W Kaur
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Tobias Ackels
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, 52074 Aachen, Germany
| | - Tsung-Han Kuo
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Annika Cichy
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, 52074 Aachen, Germany
| | - Sandeepa Dey
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Cristen Hays
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Maria Kateri
- Institute of Statistics, RWTH Aachen University, 52056 Aachen, Germany
| | - Darren W Logan
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA; Welcome Trust Sanger Institute, Hinxton, Cambridge CB10 1HH, UK
| | - Tobias F Marton
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA; Department of Psychiatry, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, 52074 Aachen, Germany
| | - Lisa Stowers
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA.
| |
Collapse
|
26
|
Burnstock G. Purinergic signalling in endocrine organs. Purinergic Signal 2014; 10:189-231. [PMID: 24265070 PMCID: PMC3944044 DOI: 10.1007/s11302-013-9396-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 01/08/2023] Open
Abstract
There is widespread involvement of purinergic signalling in endocrine biology. Pituitary cells express P1, P2X and P2Y receptor subtypes to mediate hormone release. Adenosine 5'-triphosphate (ATP) regulates insulin release in the pancreas and is involved in the secretion of thyroid hormones. ATP plays a major role in the synthesis, storage and release of catecholamines from the adrenal gland. In the ovary purinoceptors mediate gonadotrophin-induced progesterone secretion, while in the testes, both Sertoli and Leydig cells express purinoceptors that mediate secretion of oestradiol and testosterone, respectively. ATP released as a cotransmitter with noradrenaline is involved in activities of the pineal gland and in the neuroendocrine control of the thymus. In the hypothalamus, ATP and adenosine stimulate or modulate the release of luteinising hormone-releasing hormone, as well as arginine-vasopressin and oxytocin. Functionally active P2X and P2Y receptors have been identified on human placental syncytiotrophoblast cells and on neuroendocrine cells in the lung, skin, prostate and intestine. Adipocytes have been recognised recently to have endocrine function involving purinoceptors.
Collapse
Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
| |
Collapse
|
27
|
Burnstock G. Purinergic signalling in the reproductive system in health and disease. Purinergic Signal 2014; 10:157-87. [PMID: 24271059 PMCID: PMC3944041 DOI: 10.1007/s11302-013-9399-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 12/16/2022] Open
Abstract
There are multiple roles for purinergic signalling in both male and female reproductive organs. ATP, released as a cotransmitter with noradrenaline from sympathetic nerves, contracts smooth muscle via P2X1 receptors in vas deferens, seminal vesicles, prostate and uterus, as well as in blood vessels. Male infertility occurs in P2X1 receptor knockout mice. Both short- and long-term trophic purinergic signalling occurs in reproductive organs. Purinergic signalling is involved in hormone secretion, penile erection, sperm motility and capacitation, and mucous production. Changes in purinoceptor expression occur in pathophysiological conditions, including pre-eclampsia, cancer and pain.
Collapse
Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
| |
Collapse
|
28
|
Abstract
Calcium (Ca(2+)) uptake into the mitochondrial matrix is critically important to cellular function. As a regulator of matrix Ca(2+) levels, this flux influences energy production and can initiate cell death. If large, this flux could potentially alter intracellular Ca(2+) ([Ca(2+)]i) signals. Despite years of study, fundamental disagreements on the extent and speed of mitochondrial Ca(2+) uptake still exist. Here, we review and quantitatively analyze mitochondrial Ca(2+) uptake fluxes from different tissues and interpret the results with respect to the recently proposed mitochondrial Ca(2+) uniporter (MCU) candidate. This quantitative analysis yields four clear results: (i) under physiological conditions, Ca(2+) influx into the mitochondria via the MCU is small relative to other cytosolic Ca(2+) extrusion pathways; (ii) single MCU conductance is ∼6-7 pS (105 mM [Ca(2+)]), and MCU flux appears to be modulated by [Ca(2+)]i, suggesting Ca(2+) regulation of MCU open probability (P(O)); (iii) in the heart, two features are clear: the number of MCU channels per mitochondrion can be calculated, and MCU probability is low under normal conditions; and (iv) in skeletal muscle and liver cells, uptake per mitochondrion varies in magnitude but total uptake per cell still appears to be modest. Based on our analysis of available quantitative data, we conclude that although Ca(2+) critically regulates mitochondrial function, the mitochondria do not act as a significant dynamic buffer of cytosolic Ca(2+) under physiological conditions. Nevertheless, with prolonged (superphysiological) elevations of [Ca(2+)]i, mitochondrial Ca(2+) uptake can increase 10- to 1,000-fold and begin to shape [Ca(2+)]i dynamics.
Collapse
|
29
|
Mitochondrial Ca(2+) mobilization is a key element in olfactory signaling. Nat Neurosci 2012; 15:754-62. [PMID: 22446879 DOI: 10.1038/nn.3074] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 02/21/2012] [Indexed: 12/13/2022]
Abstract
In olfactory sensory neurons (OSNs), cytosolic Ca(2+) controls the gain and sensitivity of olfactory signaling. Important components of the molecular machinery that orchestrates OSN Ca(2+) dynamics have been described, but key details are still missing. Here, we demonstrate a critical physiological role of mitochondrial Ca(2+) mobilization in mouse OSNs. Combining a new mitochondrial Ca(2+) imaging approach with patch-clamp recordings, organelle mobility assays and ultrastructural analyses, our study identifies mitochondria as key determinants of olfactory signaling. We show that mitochondrial Ca(2+) mobilization during sensory stimulation shapes the cytosolic Ca(2+) response profile in OSNs, ensures a broad dynamic response range and maintains sensitivity of the spike generation machinery. When mitochondrial function is impaired, olfactory neurons function as simple stimulus detectors rather than as intensity encoders. Moreover, we describe activity-dependent recruitment of mitochondria to olfactory knobs, a mechanism that provides a context-dependent tool for OSNs to maintain cellular homeostasis and signaling integrity.
Collapse
|