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Dal N, Bilici S. An Overview of the Potential Role of Nutrition in Mental Disorders in the Light of Advances in Nutripsychiatry. Curr Nutr Rep 2024; 13:69-81. [PMID: 38329691 PMCID: PMC11133159 DOI: 10.1007/s13668-024-00520-4] [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] [Accepted: 01/21/2024] [Indexed: 02/09/2024]
Abstract
PURPOSE OF REVIEW As research on the potential impact of nutrition on mental disorders, a significant component of global disability continues to grow the concepts of "nutritional psychiatry, psycho-dietetics/nutripsychiatry" have taken their place in the literature. This review is a comprehensive examination of the literature on the the potential mechanisms between common mental disorders and nutrition and evaluates the effectiveness of dietary interventions. RECENT FINDINGS Inflammation, oxidative stress, intestinal microbiota, mitochondrial dysfunction, and neural plasticity are shown as potential mechanisms in the relationship between mental disorders and nutrition. As a matter of fact, neurotrophic factors, which make important contributions to repair mechanisms throughout life, and neuronal plasticity, which plays a role in mental disorders, are affected by nutritional factors. In metabolism, the antioxidant defense system works with nutritional cofactors and phytochemicals. A balanced, planned diet that provides these components is more likely to provide nutrients that increase resilience against the pathogenesis of mental disorders. Nutrition can be considered a risk factor for mental disorders. Therefore, developing public health strategies focused on improving diet may help reduce the global burden of mental disorders and other related diseases.
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Affiliation(s)
- Nursel Dal
- Department of Nutrition and Dietetics, Bandirma Onyedi Eylul University, Balikesir, Turkey.
| | - Saniye Bilici
- Department of Nutrition and Dietetics, Gazi University, Ankara, Turkey
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2
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McVey Neufeld KA, Mao YK, West CL, Ahn M, Hameed H, Iwashita E, Stanisz AM, Forsythe P, Barbut D, Zasloff M, Kunze WA. Squalamine reverses age-associated changes of firing patterns of myenteric sensory neurons and vagal fibres. Commun Biol 2024; 7:80. [PMID: 38200107 PMCID: PMC10781697 DOI: 10.1038/s42003-023-05623-2] [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: 05/01/2023] [Accepted: 11/21/2023] [Indexed: 01/12/2024] Open
Abstract
Vagus nerve signaling is a key component of the gut-brain axis and regulates diverse physiological processes that decline with age. Gut to brain vagus firing patterns are regulated by myenteric intrinsic primary afferent neuron (IPAN) to vagus neurotransmission. It remains unclear how IPANs or the afferent vagus age functionally. Here we identified a distinct ageing code in gut to brain neurotransmission defined by consistent differences in firing rates, burst durations, interburst and intraburst firing intervals of IPANs and the vagus, when comparing young and aged neurons. The aminosterol squalamine changed aged neurons firing patterns to a young phenotype. In contrast to young neurons, sertraline failed to increase firing rates in the aged vagus whereas squalamine was effective. These results may have implications for improved treatments involving pharmacological and electrical stimulation of the vagus for age-related mood and other disorders. For example, oral squalamine might be substituted for or added to sertraline for the aged.
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Affiliation(s)
| | - Yu-Kang Mao
- Brain-Body Institute, McMaster University, Hamilton, ON, Canada
| | - Christine L West
- Brain-Body Institute, McMaster University, Hamilton, ON, Canada
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Matthew Ahn
- Brain-Body Institute, McMaster University, Hamilton, ON, Canada
| | - Hashim Hameed
- Brain-Body Institute, McMaster University, Hamilton, ON, Canada
| | - Eiko Iwashita
- Brain-Body Institute, McMaster University, Hamilton, ON, Canada
| | | | - Paul Forsythe
- Department of Medicine, 569 Heritage Medical Research Center, University of Alberta, Edmonton, AB, Canada
| | | | - Michael Zasloff
- Enterin, Inc., Philadelphia, PA, USA.
- MedStar-Georgetown Transplant Institute, Georgetown University School of Medicine, Washington, DC, USA.
| | - Wolfgang A Kunze
- Brain-Body Institute, McMaster University, Hamilton, ON, Canada.
- Department of Biology, McMaster University, Hamilton, ON, Canada.
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.
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3
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Barth BB, Redington ER, Gautam N, Pelot NA, Grill WM. Calcium image analysis in the moving gut. Neurogastroenterol Motil 2023; 35:e14678. [PMID: 37736662 PMCID: PMC10999186 DOI: 10.1111/nmo.14678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 08/14/2023] [Accepted: 08/28/2023] [Indexed: 09/23/2023]
Abstract
BACKGROUND The neural control of gastrointestinal muscle relies on circuit activity whose underlying motifs remain limited by small-sample calcium imaging recordings confounded by motion artifact, paralytics, and muscle dissections. We present a sequence of resources to register images from moving preparations and identify out-of-focus events in widefield fluorescent microscopy. METHODS Our algorithm uses piecewise rigid registration with pathfinding to correct movements associated with smooth muscle contractions. We developed methods to identify loss-of-focus events and to simulate calcium activity to evaluate registration. KEY RESULTS By combining our methods with principal component analysis, we found populations of neurons exhibit distinct activity patterns in response to distinct stimuli consistent with hypothesized roles. The image analysis pipeline makes deeper insights possible by capturing concurrently calcium dynamics from more neurons in larger fields of view. We provide access to the source code for our algorithms and make experimental and technical recommendations to increase data quality in calcium imaging experiments. CONCLUSIONS These methods make feasible large population, robust calcium imaging recordings and permit more sophisticated network analyses and insights into neural activity patterns in the gut.
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Affiliation(s)
- Bradley B. Barth
- Department of Biomedical Engineering, Duke University, Durham, NC 27708
| | - Emily R. Redington
- Department of Biomedical Engineering, Duke University, Durham, NC 27708
- Current employment Regeneron Pharmaceuticals, Inc. Contributions to this article were made as an employee of Duke University and the views expressed do not necessarily represent the views of Regeneron Pharmaceuticals Inc
| | - Nitisha Gautam
- Department of Biomedical Engineering, Duke University, Durham, NC 27708
| | - Nicole A. Pelot
- Department of Biomedical Engineering, Duke University, Durham, NC 27708
| | - Warren M. Grill
- Department of Biomedical Engineering, Duke University, Durham, NC 27708
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4
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Leven P, Schneider R, Schneider L, Mallesh S, Vanden Berghe P, Sasse P, Kalff JC, Wehner S. β-adrenergic signaling triggers enteric glial reactivity and acute enteric gliosis during surgery. J Neuroinflammation 2023; 20:255. [PMID: 37941007 PMCID: PMC10631040 DOI: 10.1186/s12974-023-02937-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 10/27/2023] [Indexed: 11/10/2023] Open
Abstract
BACKGROUND Enteric glia contribute to the pathophysiology of various intestinal immune-driven diseases, such as postoperative ileus (POI), a motility disorder and common complication after abdominal surgery. Enteric gliosis of the intestinal muscularis externa (ME) has been identified as part of POI development. However, the glia-restricted responses and activation mechanisms are poorly understood. The sympathetic nervous system becomes rapidly activated by abdominal surgery. It modulates intestinal immunity, innervates all intestinal layers, and directly interfaces with enteric glia. We hypothesized that sympathetic innervation controls enteric glia reactivity in response to surgical trauma. METHODS Sox10iCreERT2/Rpl22HA/+ mice were subjected to a mouse model of laparotomy or intestinal manipulation to induce POI. Histological, protein, and transcriptomic analyses were performed to analyze glia-specific responses. Interactions between the sympathetic nervous system and enteric glia were studied in mice chemically depleted of TH+ sympathetic neurons and glial-restricted Sox10iCreERT2/JellyOPfl/+/Rpl22HA/+ mice, allowing optogenetic stimulation of β-adrenergic downstream signaling and glial-specific transcriptome analyses. A laparotomy model was used to study the effect of sympathetic signaling on enteric glia in the absence of intestinal manipulation. Mechanistic studies included adrenergic receptor expression profiling in vivo and in vitro and adrenergic agonism treatments of primary enteric glial cell cultures to elucidate the role of sympathetic signaling in acute enteric gliosis and POI. RESULTS With ~ 4000 differentially expressed genes, the most substantial enteric glia response occurs early after intestinal manipulation. During POI, enteric glia switch into a reactive state and continuously shape their microenvironment by releasing inflammatory and migratory factors. Sympathetic denervation reduced the inflammatory response of enteric glia in the early postoperative phase. Optogenetic and pharmacological stimulation of β-adrenergic downstream signaling triggered enteric glial reactivity. Finally, distinct adrenergic agonists revealed β-1/2 adrenoceptors as the molecular targets of sympathetic-driven enteric glial reactivity. CONCLUSIONS Enteric glia act as early responders during post-traumatic intestinal injury and inflammation. Intact sympathetic innervation and active β-adrenergic receptor signaling in enteric glia is a trigger of the immediate glial postoperative inflammatory response. With immune-activating cues originating from the sympathetic nervous system as early as the initial surgical incision, adrenergic signaling in enteric glia presents a promising target for preventing POI development.
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Affiliation(s)
- Patrick Leven
- Department of Surgery, University Hospital Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Reiner Schneider
- Department of Surgery, University Hospital Bonn, Venusberg-Campus 1, 53127, Bonn, Germany.
| | - Linda Schneider
- Department of Surgery, University Hospital Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Shilpashree Mallesh
- Department of Surgery, University Hospital Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Pieter Vanden Berghe
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Louvain, Belgium
| | - Philipp Sasse
- Institute of Physiology I, Medical Faculty, University of Bonn, Bonn, Germany
| | - Jörg C Kalff
- Department of Surgery, University Hospital Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Sven Wehner
- Department of Surgery, University Hospital Bonn, Venusberg-Campus 1, 53127, Bonn, Germany.
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Stavely R, Ott LC, Rashidi N, Sakkal S, Nurgali K. The Oxidative Stress and Nervous Distress Connection in Gastrointestinal Disorders. Biomolecules 2023; 13:1586. [PMID: 38002268 PMCID: PMC10669114 DOI: 10.3390/biom13111586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/19/2023] [Accepted: 10/23/2023] [Indexed: 11/26/2023] Open
Abstract
Oxidative stress is increasingly recognized as a central player in a range of gastrointestinal (GI) disorders, as well as complications stemming from therapeutic interventions. This article presents an overview of the mechanisms of oxidative stress in GI conditions and highlights a link between oxidative insult and disruption to the enteric nervous system (ENS), which controls GI functions. The dysfunction of the ENS is characteristic of a spectrum of disorders, including neurointestinal diseases and conditions such as inflammatory bowel disease (IBD), diabetic gastroparesis, and chemotherapy-induced GI side effects. Neurons in the ENS, while essential for normal gut function, appear particularly vulnerable to oxidative damage. Mechanistically, oxidative stress in enteric neurons can result from intrinsic nitrosative injury, mitochondrial dysfunction, or inflammation-related pathways. Although antioxidant-based therapies have shown limited efficacy, recognizing the multifaceted role of oxidative stress in GI diseases offers a promising avenue for future interventions. This comprehensive review summarizes the literature to date implicating oxidative stress as a critical player in the pathophysiology of GI disorders, with a focus on its role in ENS injury and dysfunction, and highlights opportunities for the development of targeted therapeutics for these diseases.
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Affiliation(s)
- Rhian Stavely
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Leah C. Ott
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Niloufar Rashidi
- Institute for Health and Sport, Victoria University, St Albans, VIC 3021, Australia
| | - Samy Sakkal
- Institute for Health and Sport, Victoria University, St Albans, VIC 3021, Australia
| | - Kulmira Nurgali
- Institute for Health and Sport, Victoria University, St Albans, VIC 3021, Australia
- Department of Medicine Western Health, The University of Melbourne, St Albans, VIC 3021, Australia
- Regenerative Medicine and Stem Cell Program, Australian Institute for Musculoskeletal Science (AIMSS), St Albans, VIC 3021, Australia
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Viola MF, Chavero-Pieres M, Modave E, Delfini M, Stakenborg N, Estévez MC, Fabre N, Appeltans I, Martens T, Vandereyken K, Theobald H, Van Herck J, Petry P, Verheijden S, De Schepper S, Sifrim A, Liu Z, Ginhoux F, Azhar M, Schlitzer A, Matteoli G, Kierdorf K, Prinz M, Berghe PV, Voet T, Boeckxstaens G. Dedicated macrophages organize and maintain the enteric nervous system. Nature 2023:10.1038/s41586-023-06200-7. [PMID: 37316669 DOI: 10.1038/s41586-023-06200-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 05/11/2023] [Indexed: 06/16/2023]
Abstract
Correct development and maturation of the enteric nervous system (ENS) is critical for survival1. At birth, the ENS is immature and requires considerable refinement to exert its functions in adulthood2. Here we demonstrate that resident macrophages of the muscularis externa (MMϕ) refine the ENS early in life by pruning synapses and phagocytosing enteric neurons. Depletion of MMϕ before weaning disrupts this process and results in abnormal intestinal transit. After weaning, MMϕ continue to interact closely with the ENS and acquire a neurosupportive phenotype. The latter is instructed by transforming growth factor-β produced by the ENS; depletion of the ENS and disruption of transforming growth factor-β signalling result in a decrease in neuron-associated MMϕ associated with loss of enteric neurons and altered intestinal transit. These findings introduce a new reciprocal cell-cell communication responsible for maintenance of the ENS and indicate that the ENS, similarly to the brain, is shaped and maintained by a dedicated population of resident macrophages that adapts its phenotype and transcriptome to the timely needs of the ENS niche.
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Affiliation(s)
- Maria Francesca Viola
- Laboratory for Intestinal Neuro-Immune Interaction, Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
| | - Marta Chavero-Pieres
- Laboratory for Intestinal Neuro-Immune Interaction, Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
| | - Elodie Modave
- Laboratory for Intestinal Neuro-Immune Interaction, Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
| | - Marcello Delfini
- Laboratory for Intestinal Neuro-Immune Interaction, Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
| | - Nathalie Stakenborg
- Laboratory for Intestinal Neuro-Immune Interaction, Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
| | - Maria Cuende Estévez
- Laboratory for Intestinal Neuro-Immune Interaction, Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
| | - Naomi Fabre
- Laboratory for Intestinal Neuro-Immune Interaction, Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
| | - Iris Appeltans
- Laboratory for Intestinal Neuro-Immune Interaction, Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
| | - Tobie Martens
- Laboratory for Enteric NeuroScience, Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
| | - Katy Vandereyken
- Laboratory of Reproductive Genomics, Department of Human Genetics, KU Leuven, Leuven, Belgium
- KU Leuven Institute for Single Cell Omics, KU Leuven, Leuven, Belgium
| | - Hannah Theobald
- Quantitative Systems Biology, LIMES-Institute, University of Bonn, Bonn, Germany
| | - Jens Van Herck
- Laboratory of Reproductive Genomics, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Philippe Petry
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Simon Verheijden
- Laboratory for Intestinal Neuro-Immune Interaction, Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
- Janssen Research and Development, Janssen Pharmaceutica NV, Beerse, Belgium
| | - Sebastiaan De Schepper
- Laboratory for Intestinal Neuro-Immune Interaction, Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
- UK Dementia Research Institute, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, UK
| | - Alejandro Sifrim
- KU Leuven Institute for Single Cell Omics, KU Leuven, Leuven, Belgium
- Laboratory of Multi-Omic Integrative Bioinformatics, Department of Genetics, KU Leuven, Leuven, Belgium
- Leuven AI Institute, KU Leuven, Leuven, Belgium
| | - Zhaoyuan Liu
- Shanghai Institute of Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Florent Ginhoux
- Shanghai Institute of Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Singapore Immunology Network, Agency for Science, Technology & Research, Singapore, Singapore
- Translational Immunology Institute, SingHealth Duke-NUS Academic Medical Centre, Singapore, Singapore
| | - Mohamad Azhar
- Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Andreas Schlitzer
- Quantitative Systems Biology, LIMES-Institute, University of Bonn, Bonn, Germany
| | - Gianluca Matteoli
- Laboratory for Mucosal Immunology, Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
| | - Katrin Kierdorf
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marco Prinz
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Pieter Vanden Berghe
- Laboratory for Enteric NeuroScience, Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
| | - Thierry Voet
- Laboratory of Reproductive Genomics, Department of Human Genetics, KU Leuven, Leuven, Belgium
- KU Leuven Institute for Single Cell Omics, KU Leuven, Leuven, Belgium
| | - Guy Boeckxstaens
- Laboratory for Intestinal Neuro-Immune Interaction, Translational Research Center for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium.
- KU Leuven Institute for Single Cell Omics, KU Leuven, Leuven, Belgium.
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7
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Osorio N, Martineau M, Fortea M, Rouget C, Penalba V, Lee CJ, Boesmans W, Rolli-Derkinderen M, Patel AV, Mondielli G, Conrod S, Labat-Gest V, Papin A, Sasabe J, Sweedler JV, Vanden Berghe P, Delmas P, Mothet JP. d-Serine agonism of GluN1-GluN3 NMDA receptors regulates the activity of enteric neurons and coordinates gut motility. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.19.537136. [PMID: 37131687 PMCID: PMC10153202 DOI: 10.1101/2023.04.19.537136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The enteric nervous system (ENS) is a complex network of diverse molecularly defined classes of neurons embedded in the gastrointestinal wall and responsible for controlling the major functions of the gut. As in the central nervous system, the vast array of ENS neurons is interconnected by chemical synapses. Despite several studies reporting the expression of ionotropic glutamate receptors in the ENS, their roles in the gut remain elusive. Here, by using an array of immunohistochemistry, molecular profiling and functional assays, we uncover a new role for d-serine (d-Ser) and non-conventional GluN1-GluN3 N-methyl d-aspartate receptors (NMDARs) in regulating ENS functions. We demonstrate that d-Ser is produced by serine racemase (SR) expressed in enteric neurons. By using both in situ patch clamp recording and calcium imaging, we show that d-Ser alone acts as an excitatory neurotransmitter in the ENS independently of the conventional GluN1-GluN2 NMDARs. Instead, d-Ser directly gates the non-conventional GluN1-GluN3 NMDARs in enteric neurons from both mouse and guinea-pig. Pharmacological inhibition or potentiation of GluN1-GluN3 NMDARs had opposite effects on mouse colonic motor activities, while genetically driven loss of SR impairs gut transit and fluid content of pellet output. Our results demonstrate the existence of native GluN1-GluN3 NMDARs in enteric neurons and open new perspectives on the exploration of excitatory d-Ser receptors in gut function and diseases.
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Affiliation(s)
- Nancy Osorio
- Laboratoire de Neurosciences Cognitives (LNC), Aix-Marseille-Université, CNRS, UMR 7291, Marseille, France
- Centre de Recherche en Neurophysiologie et Neuroscience de Marseille, UMR 7286, CNRS, Université Aix-Marseille, Marseille, France
| | | | - Marina Fortea
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | | | - Virginie Penalba
- Laboratoire de Neurosciences Cognitives (LNC), Aix-Marseille-Université, CNRS, UMR 7291, Marseille, France
- Centre de Recherche en Neurophysiologie et Neuroscience de Marseille, UMR 7286, CNRS, Université Aix-Marseille, Marseille, France
| | - Cindy J. Lee
- Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Werend Boesmans
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | | | - Amit V. Patel
- Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Grégoire Mondielli
- Centre de Recherche en Neurophysiologie et Neuroscience de Marseille, UMR 7286, CNRS, Université Aix-Marseille, Marseille, France
| | - Sandrine Conrod
- Centre de Recherche en Neurophysiologie et Neuroscience de Marseille, UMR 7286, CNRS, Université Aix-Marseille, Marseille, France
| | | | - Amandine Papin
- Laboratoire de Neurosciences Cognitives (LNC), Aix-Marseille-Université, CNRS, UMR 7291, Marseille, France
| | - Jumpei Sasabe
- Department of Pharmacology, Keio University School of Medicine, Tokyo, Japan
| | - Jonathan V. Sweedler
- Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Pieter Vanden Berghe
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | - Patrick Delmas
- Laboratoire de Neurosciences Cognitives (LNC), Aix-Marseille-Université, CNRS, UMR 7291, Marseille, France
- Centre de Recherche en Neurophysiologie et Neuroscience de Marseille, UMR 7286, CNRS, Université Aix-Marseille, Marseille, France
| | - Jean-Pierre Mothet
- Neurocentre Magendie, INSERM UMR U862, Bordeaux, France
- Centre de Recherche en Neurophysiologie et Neuroscience de Marseille, UMR 7286, CNRS, Université Aix-Marseille, Marseille, France
- Université Paris-Saclay, École Normale Supérieure Paris-Saclay, Centre National de la Recherche Scientifique, CentraleSupélec, LuMIn UMR9024, Gif-sur-Yvette 91190, France
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8
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Walters GC, Usachev YM. Mitochondrial calcium cycling in neuronal function and neurodegeneration. Front Cell Dev Biol 2023; 11:1094356. [PMID: 36760367 PMCID: PMC9902777 DOI: 10.3389/fcell.2023.1094356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/12/2023] [Indexed: 01/26/2023] Open
Abstract
Mitochondria are essential for proper cellular function through their critical roles in ATP synthesis, reactive oxygen species production, calcium (Ca2+) buffering, and apoptotic signaling. In neurons, Ca2+ buffering is particularly important as it helps to shape Ca2+ signals and to regulate numerous Ca2+-dependent functions including neuronal excitability, synaptic transmission, gene expression, and neuronal toxicity. Over the past decade, identification of the mitochondrial Ca2+ uniporter (MCU) and other molecular components of mitochondrial Ca2+ transport has provided insight into the roles that mitochondrial Ca2+ regulation plays in neuronal function in health and disease. In this review, we discuss the many roles of mitochondrial Ca2+ uptake and release mechanisms in normal neuronal function and highlight new insights into the Ca2+-dependent mechanisms that drive mitochondrial dysfunction in neurologic diseases including epilepsy, Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. We also consider how targeting Ca2+ uptake and release mechanisms could facilitate the development of novel therapeutic strategies for neurological diseases.
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Affiliation(s)
- Grant C. Walters
- Department of Neuroscience and Pharmacology, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States
| | - Yuriy M. Usachev
- Department of Neuroscience and Pharmacology, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States
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9
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Helaly AMN, Ghorab DSED. Schizophrenia as metabolic disease. What are the causes? Metab Brain Dis 2023; 38:795-804. [PMID: 36656396 PMCID: PMC9849842 DOI: 10.1007/s11011-022-01147-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 12/14/2022] [Indexed: 01/20/2023]
Abstract
Schizophrenia (SZ) is a devastating neurodevelopmental disease with an accelerated ageing feature. The criteria of metabolic disease firmly fit with those of schizophrenia. Disturbances in energy and mitochondria are at the core of complex pathology. Genetic and environmental interaction creates changes in redox, inflammation, and apoptosis. All the factors behind schizophrenia interact in a cycle where it is difficult to discriminate between the cause and the effect. New technology and advances in the multi-dispensary fields could break this cycle in the future.
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Affiliation(s)
- Ahmed Mohamed Nabil Helaly
- Clinical Science, Faculty of Medicine, Yarmouk University, Irbid, Jordan.
- Forensic Medicine and Toxicology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt.
| | - Doaa Shame El Din Ghorab
- Basic Science, Faculty of Medicine, Yarmouk University, Irbid, Jordan
- Pathology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
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10
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Dubonyte U, Asenjo-Martinez A, Werge T, Lage K, Kirkeby A. Current advancements of modelling schizophrenia using patient-derived induced pluripotent stem cells. Acta Neuropathol Commun 2022; 10:183. [PMID: 36527106 PMCID: PMC9756764 DOI: 10.1186/s40478-022-01460-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/12/2022] [Indexed: 12/23/2022] Open
Abstract
Schizophrenia (SZ) is a severe psychiatric disorder, with a prevalence of 1-2% world-wide and substantial health- and social care costs. The pathology is influenced by both genetic and environmental factors, however the underlying cause still remains elusive. SZ has symptoms including delusions, hallucinations, confused thoughts, diminished emotional responses, social withdrawal and anhedonia. The onset of psychosis is usually in late adolescence or early adulthood. Multiple genome-wide association and whole exome sequencing studies have provided extraordinary insights into the genetic variants underlying familial as well as polygenic forms of the disease. Nonetheless, a major limitation in schizophrenia research remains the lack of clinically relevant animal models, which in turn hampers the development of novel effective therapies for the patients. The emergence of human induced pluripotent stem cell (hiPSC) technology has allowed researchers to work with SZ patient-derived neuronal and glial cell types in vitro and to investigate the molecular basis of the disorder in a human neuronal context. In this review, we summarise findings from available studies using hiPSC-based neural models and discuss how these have provided new insights into molecular and cellular pathways of SZ. Further, we highlight different examples of how these models have shown alterations in neurogenesis, neuronal maturation, neuronal connectivity and synaptic impairment as well as mitochondrial dysfunction and dysregulation of miRNAs in SZ patient-derived cultures compared to controls. We discuss the pros and cons of these models and describe the potential of using such models for deciphering the contribution of specific human neural cell types to the development of the disease.
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Affiliation(s)
- Ugne Dubonyte
- grid.5254.60000 0001 0674 042XDepartment of Neuroscience and Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW), University of Copenhagen, Copenhagen, Denmark
| | - Andrea Asenjo-Martinez
- grid.5254.60000 0001 0674 042XDepartment of Neuroscience and Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW), University of Copenhagen, Copenhagen, Denmark
| | - Thomas Werge
- grid.466916.a0000 0004 0631 4836Institute of Biological Psychiatry, Mental Health Services, Copenhagen University Hospital, Copenhagen, Denmark ,grid.5254.60000 0001 0674 042XDepartment of Clinical Medicine and Lundbeck Foundation Center for GeoGenetics, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | - Kasper Lage
- grid.466916.a0000 0004 0631 4836Institute of Biological Psychiatry, Mental Health Services, Copenhagen University Hospital, Copenhagen, Denmark ,grid.66859.340000 0004 0546 1623Stanley Center for Psychiatric Research and The Novo Nordisk Foundation Center for Genomic Mechanisms of Disease, Broad Institute of MIT and Harvard, Cambridge, MA USA ,grid.32224.350000 0004 0386 9924Department of Surgery, Massachusetts General Hospital, Boston, MA USA
| | - Agnete Kirkeby
- grid.5254.60000 0001 0674 042XDepartment of Neuroscience and Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW), University of Copenhagen, Copenhagen, Denmark ,grid.4514.40000 0001 0930 2361Department of Experimental Medical Science and Wallenberg Center for Molecular Medicine, Lund University, Lund, Sweden
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11
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Li Z, Boesmans W, Kazwiny Y, Hao MM, Vanden Berghe P. Simultaneous whole-cell patch-clamp and calcium imaging on myenteric neurons. Am J Physiol Gastrointest Liver Physiol 2022; 323:G341-G347. [PMID: 36044672 DOI: 10.1152/ajpgi.00162.2022] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Live calcium imaging is often used as a proxy for electrophysiological measurements and has been a valuable tool that allows simultaneous analysis of neuronal activity in multiple cells at the population level. In the enteric nervous system, there are two main electrophysiological classes of neurons, after-hyperpolarizing (AH)- and synaptic (S)-neurons, which have been shown to have different calcium handling mechanisms. However, they are rarely considered separately in calcium imaging experiments. A handful of studies have shown that in guinea pig, a calcium transient will accompany a single action potential in AH-neurons, but multiple action potentials are required to generate a calcium transient in S-neurons. How this translates to different modes of cellular depolarization and whether this is consistent across species is unknown. In this study, we used simultaneous whole-cell patch-clamp electrophysiology together with calcium imaging to investigate how enteric neurons respond to different modes of depolarization. Using both traditional (4 Hz) and also high-speed (1,000 Hz) imaging techniques, we found that single action potentials elicit calcium transients in both AH-neurons and S-neurons. Subthreshold membrane depolarizations were also able to elicit calcium transients, although calcium responses were generally amplified if an action potential was present. Furthermore, we identified that responses to nicotinic acetylcholine receptor stimulation can be used to distinguish between AH- and S-neurons in calcium imaging.NEW & NOTEWORTHY Live calcium imaging is an important tool for investigating enteric nervous system (ENS) function. Previous studies have shown that multiple action potentials are needed to generate a calcium response in S-neurons, which has important implications for the interpretation of calcium imaging data. Here, we show that in mouse myenteric neurons, calcium transients are elicited by single action potentials in both AH- and S-neurons. In addition, nicotinic acetylcholine receptor stimulation can be used to distinguish between these two classes.
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Affiliation(s)
- Zhiling Li
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, ChroMeta, Katholieke Universiteit Leuven, Leuven, Belgium.,The Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, People's Republic of China
| | - Werend Boesmans
- Biomedical Research Institute, Hasselt University, Hasselt, Belgium.,Department of Pathology, GROW-School for Oncology and Reproduction, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Youcef Kazwiny
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, ChroMeta, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Marlene M Hao
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, ChroMeta, Katholieke Universiteit Leuven, Leuven, Belgium.,Department of Anatomy and Physiology, The University of Melbourne, Parkville, Victoria, Australia
| | - Pieter Vanden Berghe
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, ChroMeta, Katholieke Universiteit Leuven, Leuven, Belgium.,Leuven Brain Institute, Katholieke Universiteit Leuven, Leuven, Belgium
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12
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Ni P, Ma Y, Chung S. Mitochondrial dysfunction in psychiatric disorders. Schizophr Res 2022:S0920-9964(22)00333-4. [PMID: 36175250 DOI: 10.1016/j.schres.2022.08.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 08/25/2022] [Accepted: 08/30/2022] [Indexed: 11/30/2022]
Abstract
Psychiatric disorders are a heterogeneous group of mental disorders with abnormal mental or behavioral patterns, which severely distress or disable affected individuals and can have a grave socioeconomic burden. Growing evidence indicates that mitochondrial function plays an important role in developing psychiatric disorders. This review discusses the neuropsychiatric consequences of mitochondrial abnormalities in both animal models and patients. We also discuss recent studies associated with compromised mitochondrial function in various psychiatric disorders, such as schizophrenia (SCZ), major depressive disorder (MD), and bipolar disorders (BD). These studies employ various approaches including postmortem studies, imaging studies, genetic studies, and induced pluripotent stem cells (iPSCs) studies. We also summarize the evidence from animal models and clinical trials to support mitochondrial function as a potential therapeutic target to treat various psychiatric disorders. This review will contribute to furthering our understanding of the metabolic etiology of various psychiatric disorders, and help guide the development of optimal therapies.
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Affiliation(s)
- Peiyan Ni
- The Psychiatric Laboratory and Mental Health Center, West China Hospital, Sichuan University, Chengdu 610041, People's Republic of China.
| | - Yao Ma
- The Psychiatric Laboratory and Mental Health Center, West China Hospital, Sichuan University, Chengdu 610041, People's Republic of China
| | - Sangmi Chung
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595, USA.
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13
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Groten CJ, MacVicar BA. Mitochondrial Ca 2+ uptake by the MCU facilitates pyramidal neuron excitability and metabolism during action potential firing. Commun Biol 2022; 5:900. [PMID: 36056095 PMCID: PMC9440007 DOI: 10.1038/s42003-022-03848-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 08/16/2022] [Indexed: 12/12/2022] Open
Abstract
Neuronal activation is fundamental to information processing by the brain and requires mitochondrial energy metabolism. Mitochondrial Ca2+ uptake by the mitochondrial Ca2+ uniporter (MCU) has long been implicated in the control of energy metabolism and intracellular Ca2+ signalling, but its importance to neuronal function in the brain remains unclear. Here, we used in situ electrophysiology and two-photon imaging of mitochondrial Ca2+, cytosolic Ca2+, and NAD(P)H to test the relevance of MCU activation to pyramidal neuron Ca2+ signalling and energy metabolism during action potential firing. We demonstrate that mitochondrial Ca2+ uptake by the MCU is tuned to enhanced firing rate and the strength of this relationship varied between neurons of discrete brain regions. MCU activation promoted electron transport chain activity and chemical reduction of NAD+ to NADH. Moreover, Ca2+ buffering by mitochondria attenuated cytosolic Ca2+ signals and thereby reduced the coupling between activity and the slow afterhyperpolarization, a ubiquitous regulator of excitability. Collectively, we demonstrate that the MCU is engaged by accelerated spike frequency to facilitate neuronal activity through simultaneous control of energy metabolism and excitability. As such, the MCU is situated to promote brain functions associated with high frequency signalling and may represent a target for controlling excessive neuronal activity.
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Affiliation(s)
- Christopher J Groten
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, V6T 1Z3, Canada.
| | - Brian A MacVicar
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, V6T 1Z3, Canada.
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14
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Fung C, Cools B, Malagola S, Martens T, Tack J, Kazwiny Y, Vanden Berghe P. Luminal short-chain fatty acids and 5-HT acutely activate myenteric neurons in the mouse proximal colon. Neurogastroenterol Motil 2021; 33:e14186. [PMID: 34121274 DOI: 10.1111/nmo.14186] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 04/03/2021] [Accepted: 05/04/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND Gastrointestinal (GI) function is critically dependent on the control of the enteric nervous system (ENS), which is situated within the gut wall and organized into two ganglionated nerve plexuses: the submucosal and myenteric plexus. The ENS is optimally positioned and together with the intestinal epithelium, is well-equipped to monitor the luminal contents such as microbial metabolites and to coordinate appropriate responses accordingly. Despite the heightened interest in the gut microbiota and its influence on intestinal physiology and pathophysiology, how they interact with the host ENS remains unclear. METHODS Using full-thickness proximal colon preparations from transgenic Villin-CreERT2;R26R-GCaMP3 and Wnt1-Cre;R26R-GCaMP3 mice, which express a fluorescent Ca2+ indicator in their intestinal epithelium or in their ENS, respectively, we examined the effects of key luminal microbial metabolites (SCFAs and 5-HT) on the mucosa and underlying enteric neurons. KEY RESULTS We show that the SCFAs acetate, propionate, and butyrate, as well as 5-HT can, to varying extents, acutely elicit epithelial and neuronal Ca2+ responses. Furthermore, SCFAs exert differential effects on submucosal and myenteric neurons. Additionally, we found that submucosal ganglia are predominantly aligned along the striations of the transverse mucosal folds in the proximal colon. CONCLUSIONS & INFERENCES Taken together, our study demonstrates that different microbial metabolites, including SCFAs and 5-HT, can acutely stimulate Ca2+ signaling in the mucosal epithelium and in enteric neurons.
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Affiliation(s)
- Candice Fung
- Laboratory for Enteric NeuroScience (LENS) Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | - Bert Cools
- Laboratory for Enteric NeuroScience (LENS) Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | - Sergio Malagola
- Laboratory for Enteric NeuroScience (LENS) Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | - Tobias Martens
- Laboratory for Enteric NeuroScience (LENS) Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | - Jan Tack
- Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | - Youcef Kazwiny
- Laboratory for Enteric NeuroScience (LENS) Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | - Pieter Vanden Berghe
- Laboratory for Enteric NeuroScience (LENS) Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
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15
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Dynamic integration of enteric neural stem cells in ex vivo organotypic colon cultures. Sci Rep 2021; 11:15889. [PMID: 34354183 PMCID: PMC8342505 DOI: 10.1038/s41598-021-95434-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 07/26/2021] [Indexed: 11/12/2022] Open
Abstract
Enteric neural stem cells (ENSC) have been identified as a possible treatment for enteric neuropathies. After in vivo transplantation, ENSC and their derivatives have been shown to engraft within colonic tissue, migrate and populate endogenous ganglia, and functionally integrate with the enteric nervous system. However, the mechanisms underlying the integration of donor ENSC, in recipient tissues, remain unclear. Therefore, we aimed to examine ENSC integration using an adapted ex vivo organotypic culture system. Donor ENSC were obtained from Wnt1cre/+;R26RYFP/YFP mice allowing specific labelling, selection and fate-mapping of cells. YFP+ neurospheres were transplanted to C57BL6/J (6–8-week-old) colonic tissue and maintained in organotypic culture for up to 21 days. We analysed and quantified donor cell integration within recipient tissues at 7, 14 and 21 days, along with assessing the structural and molecular consequences of ENSC integration. We found that organotypically cultured tissues were well preserved up to 21-days in ex vivo culture, which allowed for assessment of donor cell integration after transplantation. Donor ENSC-derived cells integrated across the colonic wall in a dynamic fashion, across a three-week period. Following transplantation, donor cells displayed two integrative patterns; longitudinal migration and medial invasion which allowed donor cells to populate colonic tissue. Moreover, significant remodelling of the intestinal ECM and musculature occurred upon transplantation, to facilitate donor cell integration within endogenous enteric ganglia. These results provide critical evidence on the timescale and mechanisms, which regulate donor ENSC integration, within recipient gut tissue, which are important considerations in the future clinical translation of stem cell therapies for enteric disease.
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16
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iPSC-derived homogeneous populations of developing schizophrenia cortical interneurons have compromised mitochondrial function. Mol Psychiatry 2020; 25:2873-2888. [PMID: 31019265 PMCID: PMC6813882 DOI: 10.1038/s41380-019-0423-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 03/23/2019] [Accepted: 04/03/2019] [Indexed: 02/05/2023]
Abstract
Schizophrenia (SCZ) is a neurodevelopmental disorder. Thus, studying pathogenetic mechanisms underlying SCZ requires studying the development of brain cells. Cortical interneurons (cINs) are consistently observed to be abnormal in SCZ postmortem brains. These abnormalities may explain altered gamma oscillation and cognitive function in patients with SCZ. Of note, currently used antipsychotic drugs ameliorate psychosis, but they are not very effective in reversing cognitive deficits. Characterizing mechanisms of SCZ pathogenesis, especially related to cognitive deficits, may lead to improved treatments. We generated homogeneous populations of developing cINs from 15 healthy control (HC) iPSC lines and 15 SCZ iPSC lines. SCZ cINs, but not SCZ glutamatergic neurons, show dysregulated Oxidative Phosphorylation (OxPhos) related gene expression, accompanied by compromised mitochondrial function. The OxPhos deficit in cINs could be reversed by Alpha Lipoic Acid/Acetyl-L-Carnitine (ALA/ALC) but not by other chemicals previously identified as increasing mitochondrial function. The restoration of mitochondrial function by ALA/ALC was accompanied by a reversal of arborization deficits in SCZ cINs. OxPhos abnormality, even in the absence of any circuit environment with other neuronal subtypes, appears to be an intrinsic deficit in SCZ cINs.
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17
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Activated microglia cause metabolic disruptions in developmental cortical interneurons that persist in interneurons from individuals with schizophrenia. Nat Neurosci 2020; 23:1352-1364. [PMID: 33097921 PMCID: PMC7769122 DOI: 10.1038/s41593-020-00724-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 09/16/2020] [Indexed: 02/06/2023]
Abstract
The mechanisms by which prenatal immune activation increase risk for neuropsychiatric disorders are unclear. Here, we generated developmental cortical interneurons (cINs), known to be affected in schizophrenia (SCZ) when matured, from induced pluripotent stem cells (iPSCs) from healthy controls (HC) and SCZ patients, and cocultured them with or without activated microglia. Coculture with activated microglia disturbed metabolic pathways, as indicated by unbiased transcriptome analysis, and impaired mitochondrial function, arborization, synapse formation and synaptic GABA release. Deficits in mitochondrial function and arborization were reversed by Alpha Lipoic Acid/Acetyl-L-Carnitine (ALA/ALC) treatments that boost mitochondrial function. Notably, activated microglia-conditioned medium altered metabolism in cINs and HC-derived iPSCs but not in SCZ-patient-derived iPSCs or in glutamatergic neurons. After removal of activated microglia-conditioned medium, SCZ cINs but not HC cINs showed prolonged metabolic deficits, suggesting an interaction between SCZ genetic backgrounds and environmental risk factors.
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18
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Ni P, Chung S. Mitochondrial Dysfunction in Schizophrenia. Bioessays 2020; 42:e1900202. [PMID: 32338416 DOI: 10.1002/bies.201900202] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 02/29/2020] [Indexed: 02/05/2023]
Abstract
Schizophrenia (SCZ) is a severe neurodevelopmental disorder affecting 1% of populations worldwide with a grave disability and socioeconomic burden. Current antipsychotic medications are effective treatments for positive symptoms, but poorly address negative symptoms and cognitive symptoms, warranting the development of better treatment options. Further understanding of SCZ pathogenesis is critical in these endeavors. Accumulating evidence has pointed to the role of mitochondria and metabolic dysregulation in SCZ pathogenesis. This review critically summarizes recent studies associating a compromised mitochondrial function with people with SCZ, including postmortem studies, imaging studies, genetic studies, and induced pluripotent stem cell studies. This review also discusses animal models with mitochondrial dysfunction resulting in SCZ-relevant neurobehavioral abnormalities, as well as restoration of mitochondrial function as potential therapeutic targets. Further understanding of mitochondrial dysfunction in SCZ may open the door to develop novel therapeutic strategies that can address the symptoms that cannot be adequately addressed by current antipsychotics alone.
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Affiliation(s)
- Peiyan Ni
- Psychiatric Laboratory and Mental Health Center, The State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Sangmi Chung
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, 10595, USA
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19
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Hao MM, Fung C, Boesmans W, Lowette K, Tack J, Vanden Berghe P. Development of the intrinsic innervation of the small bowel mucosa and villi. Am J Physiol Gastrointest Liver Physiol 2020; 318:G53-G65. [PMID: 31682159 DOI: 10.1152/ajpgi.00264.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Detection of nutritional and noxious food components in the gut is a crucial component of gastrointestinal function. Contents in the gut lumen interact with enteroendocrine cells dispersed throughout the gut epithelium. Enteroendocrine cells release many different hormones, neuropeptides, and neurotransmitters that communicate either directly or indirectly with the central nervous system and the enteric nervous system, a network of neurons and glia located within the gut wall. Several populations of enteric neurons extend processes that innervate the gastrointestinal lamina propria; however, how these processes develop and begin to transmit information from the mucosa is not fully understood. In this study, we found that Tuj1-immunoreactive neurites begin to project out of the myenteric plexus at embryonic day (E)13.5 in the mouse small intestine, even before the formation of villi. Using live calcium imaging, we discovered that neurites were capable of transmitting electrical information from stimulated villi to the plexus by E15.5. In unpeeled gut preparations where all layers were left intact, we also mimicked the basolateral release of 5-HT from enteroendocrine cells, which triggered responses in myenteric cell bodies at postnatal day (P)0. Altogether, our results show that enteric neurons extend neurites out of the myenteric plexus early during mouse enteric nervous system development, innervating the gastrointestinal mucosa, even before villus formation in mice of either sex. Neurites are already able to conduct electrical information at E15.5, and responses to 5-HT develop postnatally.NEW & NOTEWORTHY How enteric neurons project into the gut mucosa and begin to communicate with the epithelium during development is not known. Our study shows that enteric neurites project into the lamina propria as early as E13.5 in the mouse, before development of the submucous plexus and before formation of intestinal villi. These neurites are capable of transmitting electrical signals back to their cell bodies by E15.5 and respond to serotonin applied to neurite terminals by birth.
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Affiliation(s)
- Marlene M Hao
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, University of Leuven, Belgium.,Department of Anatomy and Neuroscience, the University of Melbourne, Australia
| | - Candice Fung
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, University of Leuven, Belgium
| | - Werend Boesmans
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, University of Leuven, Belgium.,Department of Pathology, GROW, School for Oncology and Developmental Biology, Maastricht University Medical Center, The Netherlands.,Biomedical Research Institute, Hasselt University, Hasselt, Belgium
| | - Katrien Lowette
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, University of Leuven, Belgium
| | - Jan Tack
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, University of Leuven, Belgium
| | - Pieter Vanden Berghe
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, University of Leuven, Belgium
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20
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Swaminathan M, Fung C, Finkelstein DI, Bornstein JC, Foong JPP. α-Synuclein Regulates Development and Function of Cholinergic Enteric Neurons in the Mouse Colon. Neuroscience 2019; 423:76-85. [PMID: 31705886 DOI: 10.1016/j.neuroscience.2019.10.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/15/2019] [Accepted: 10/16/2019] [Indexed: 02/07/2023]
Abstract
Alpha-Synuclein (α-Syn) is expressed in the central nervous system and the nervous system of the gut (enteric nervous system, ENS), and is well known to be the major constituent of Lewy bodies which are the hallmark of Parkinson's disease. Gastrointestinal disorders frequently manifest several years before motor deficits develop in Parkinson's patients. Despite extensive research on pathological rodent models, the physiological role of α-Syn in the normal ENS is unclear hampering analysis of its neuropathology. We compared the ENS in colons of α-Syn-knockout (α-Syn KO) and wild-type mice using immunohistochemistry and calcium-imaging of responses to synaptic input. We found that α-Syn is predominantly expressed in cholinergic varicosities, which contain vesicular acetylcholine transporter. α-Syn KO mice had higher enteric neuron density and a larger proportion of cholinergic neurons, notably those containing calretinin, demonstrating a role for α-Syn in regulating development of these neurons. Moreover, α-Syn deletion enhanced the amplitude of synaptically activated [Ca2+]i transients that are primarily mediated by acetylcholine activating nicotinic receptors suggesting that α-Syn modulates the availability of acetylcholine in enteric nerve terminals.
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Affiliation(s)
- M Swaminathan
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - C Fung
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - D I Finkelstein
- The Florey Institute of Neuroscience and Mental Health, Kenneth Myer Building, The University of Melbourne, Parkville, VIC, Australia
| | - J C Bornstein
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - J P P Foong
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia.
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21
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Swaminathan M, Hill-Yardin EL, Bornstein JC, Foong JPP. Endogenous Glutamate Excites Myenteric Calbindin Neurons by Activating Group I Metabotropic Glutamate Receptors in the Mouse Colon. Front Neurosci 2019; 13:426. [PMID: 31118881 PMCID: PMC6504831 DOI: 10.3389/fnins.2019.00426] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 04/15/2019] [Indexed: 12/20/2022] Open
Abstract
Glutamate is a classic excitatory neurotransmitter in the central nervous system (CNS), but despite several studies reporting the expression of glutamate together with its various receptors and transporters within the enteric nervous system (ENS), its role in the gut remains elusive. In this study, we characterized the expression of the vesicular glutamate transporter, vGluT2, and examined the function of glutamate in the myenteric plexus of the distal colon by employing calcium (Ca2+)-imaging on Wnt1-Cre; R26R-GCaMP3 mice which express a genetically encoded fluorescent Ca2+ indicator in all enteric neurons and glia. Most vGluT2 labeled varicosities contained the synaptic vesicle release protein, synaptophysin, but not vesicular acetylcholine transporter, vAChT, which labels vesicles containing acetylcholine, the primary excitatory neurotransmitter in the ENS. The somata of all calbindin (calb) immunoreactive neurons examined received close contacts from vGluT2 varicosities, which were more numerous than those contacting nitrergic neurons. Exogenous application of L-glutamic acid (L-Glu) and N-methyl-D-aspartate (NMDA) transiently increased the intracellular Ca2+ concentration [Ca2+]i in about 25% of myenteric neurons. Most L-Glu responsive neurons were calb immunoreactive. Blockade of NMDA receptors with APV significantly reduced the number of neurons responsive to L-Glu and NMDA, thus showing functional expression of NMDA receptors on enteric neurons. However, APV resistant responses to L-Glu and NMDA suggest that other glutamate receptors were present. APV did not affect [Ca2+]i transients evoked by electrical stimulation of interganglionic nerve fiber tracts, which suggests that NMDA receptors are not involved in synaptic transmission. The group I metabotropic glutamate receptor (mGluR) antagonist, PHCCC, significantly reduced the amplitude of [Ca2+]i transients evoked by a 20 pulse (20 Hz) train of electrical stimuli in L-Glu responsive neurons. This stimulus is known to induce slow synaptic depolarizations. Further, some neurons that had PHCCC sensitive [Ca2+]i transients were calb immunoreactive and received vGluT2 varicosities. Overall, we conclude that electrically evoked release of endogenous glutamate mediates slow synaptic transmission via activation of group I mGluRs expressed by myenteric neurons, particularly those immunoreactive for calb.
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Affiliation(s)
- Mathusi Swaminathan
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Elisa L Hill-Yardin
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia.,School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, Australia
| | - Joel C Bornstein
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Jaime P P Foong
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
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22
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Li Z, Hao MM, Van den Haute C, Baekelandt V, Boesmans W, Vanden Berghe P. Regional complexity in enteric neuron wiring reflects diversity of motility patterns in the mouse large intestine. eLife 2019; 8:42914. [PMID: 30747710 PMCID: PMC6391068 DOI: 10.7554/elife.42914] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 02/11/2019] [Indexed: 02/06/2023] Open
Abstract
The enteric nervous system controls a variety of gastrointestinal functions including intestinal motility. The minimal neuronal circuit necessary to direct peristalsis is well-characterized but several intestinal regions display also other motility patterns for which the underlying circuits and connectivity schemes that coordinate the transition between those patterns are poorly understood. We investigated whether in regions with a richer palette of motility patterns, the underlying nerve circuits reflect this complexity. Using Ca2+ imaging, we determined the location and response fingerprint of large populations of enteric neurons upon focal network stimulation. Complemented by neuronal tracing and volumetric reconstructions of synaptic contacts, this shows that the multifunctional proximal colon requires specific additional circuit components as compared to the distal colon, where peristalsis is the predominant motility pattern. Our study reveals that motility control is hard-wired in the enteric neural networks and that circuit complexity matches the motor pattern portfolio of specific intestinal regions.
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Affiliation(s)
- Zhiling Li
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | - Marlene M Hao
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Australia
| | - Chris Van den Haute
- Laboratory for Neurobiology and Gene Therapy, Department of Neurosciences, KU Leuven, Leuven, Belgium.,Leuven Viral Vector Core, KU Leuven, Leuven, Belgium
| | - Veerle Baekelandt
- Laboratory for Neurobiology and Gene Therapy, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Werend Boesmans
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium.,Department of Pathology, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, The Netherlands.,Biomedical Research Institute (BIOMED), Hasselt University, Hasselt, Belgium
| | - Pieter Vanden Berghe
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
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Boesmans W, Hao MM, Fung C, Li Z, Van den Haute C, Tack J, Pachnis V, Vanden Berghe P. Structurally defined signaling in neuro-glia units in the enteric nervous system. Glia 2019; 67:1167-1178. [PMID: 30730592 PMCID: PMC6593736 DOI: 10.1002/glia.23596] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 01/11/2019] [Accepted: 01/11/2019] [Indexed: 12/21/2022]
Abstract
Coordination of gastrointestinal function relies on joint efforts of enteric neurons and glia, whose crosstalk is vital for the integration of their activity. To investigate the signaling mechanisms and to delineate the spatial aspects of enteric neuron-to-glia communication within enteric ganglia we developed a method to stimulate single enteric neurons while monitoring the activity of neighboring enteric glial cells. We combined cytosolic calcium uncaging of individual enteric neurons with calcium imaging of enteric glial cells expressing a genetically encoded calcium indicator and demonstrate that enteric neurons signal to enteric glial cells through pannexins using paracrine purinergic pathways. Sparse labeling of enteric neurons and high-resolution analysis of the structural relation between neuronal cell bodies, varicose release sites and enteric glia uncovered that this form of neuron-to-glia communication is contained between the cell body of an enteric neuron and its surrounding enteric glial cells. Our results reveal the spatial and functional foundation of neuro-glia units as an operational cellular assembly in the enteric nervous system.
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Affiliation(s)
- Werend Boesmans
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium.,Department of Pathology, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, The Netherlands.,Biomedical Research Institute (BIOMED), Hasselt University, Hasselt, Belgium
| | - Marlene M Hao
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium.,Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Australia
| | - Candice Fung
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | - Zhiling Li
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | - Chris Van den Haute
- Laboratory for Neurobiology and Gene Therapy, Department of Neurosciences, University of Leuven, Leuven, Belgium.,Leuven Viral Vector Core, University of Leuven, Leuven, Belgium
| | - Jan Tack
- Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | - Vassilis Pachnis
- Development and Homeostasis of the Nervous System Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Pieter Vanden Berghe
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
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24
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Li D, Paterson DJ. Pre-synaptic sympathetic calcium channels, cyclic nucleotide-coupled phosphodiesterases and cardiac excitability. Semin Cell Dev Biol 2019; 94:20-27. [PMID: 30658154 DOI: 10.1016/j.semcdb.2019.01.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 01/07/2019] [Accepted: 01/14/2019] [Indexed: 12/20/2022]
Abstract
In sympathetic neurons innervating the heart, action potentials activate voltage-gated Ca2+ channels and evoke Ca2+ entry into presynaptic terminals triggering neurotransmitter release. Binding of transmitters to specific receptors stimulates signal transduction pathways that cause changes in cardiac function. The mechanisms contributing to presynaptic Ca2+ dynamics involve regulation of endogenous Ca2+ buffers, in particular the endoplasmic reticulum, mitochondria and cyclic nucleotide targeted pathways. The purpose of this review is to summarize and highlight recent findings about Ca2+ homeostasis in cardiac sympathetic neurons and how modulation of second messengers can drive neurotransmission and affect myocyte excitability in cardiovascular disease. Moreover, we discuss the underlying mechanism of abnormal intracellular Ca2+ homeostasis and signaling in these neurons, and speculate on the role of phosphodiesterases as a therapeutic target to restore normal autonomic transmission in disease states of overactivity.
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Affiliation(s)
- Dan Li
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Parks Road, Oxford, OX1 3PT, UK.
| | - David J Paterson
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Parks Road, Oxford, OX1 3PT, UK.
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25
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Fung C, Koussoulas K, Unterweger P, Allen AM, Bornstein JC, Foong JPP. Cholinergic Submucosal Neurons Display Increased Excitability Following in Vivo Cholera Toxin Exposure in Mouse Ileum. Front Physiol 2018; 9:260. [PMID: 29618987 PMCID: PMC5871806 DOI: 10.3389/fphys.2018.00260] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 03/06/2018] [Indexed: 12/16/2022] Open
Abstract
Cholera-induced hypersecretion causes dehydration and death if untreated. Cholera toxin (CT) partly acts via the enteric nervous system (ENS) and induces long-lasting changes to enteric neuronal excitability following initial exposure, but the specific circuitry involved remains unclear. We examined this by first incubating CT or saline (control) in mouse ileal loops in vivo for 3.5 h and then assessed neuronal excitability in vitro using Ca2+ imaging and immunolabeling for the activity-dependent markers cFos and pCREB. Mice from a C57BL6 background, including Wnt1-Cre;R26R-GCaMP3 mice which express the fluorescent Ca2+ indicator GCaMP3 in its ENS, were used. Ca2+-imaging using this mouse model is a robust, high-throughput method which allowed us to examine the activity of numerous enteric neurons simultaneously and post-hoc immunohistochemistry enabled the neurochemical identification of the active neurons. Together, this provided novel insight into the CT-affected circuitry that was previously impossible to attain at such an accelerated pace. Ussing chamber measurements of electrogenic ion secretion showed that CT-treated preparations had higher basal secretion than controls. Recordings of Ca2+ activity from the submucous plexus showed that increased numbers of neurons were spontaneously active in CT-incubated tissue (control: 4/149; CT: 32/160; Fisher's exact test, P < 0.0001) and that cholinergic neurons were more responsive to electrical (single pulse and train of 20 pulses) or nicotinic (1,1-dimethyl-4-phenylpiperazinium (DMPP; 10 μM) stimulation. Expression of the neuronal activity marker, pCREB, was also increased in the CT-treated submucous plexus neurons. c-Fos expression and spontaneous fast excitatory postsynaptic potentials (EPSPs), recorded by intracellular electrodes, were increased by CT exposure in a small subset of myenteric neurons. However, the effect of CT on the myenteric plexus is less clear as spontaneous Ca2+ activity and electrical- or nicotinic-evoked Ca2+ responses were reduced. Thus, in a model where CT exposure evokes hypersecretion, we observed sustained activation of cholinergic secretomotor neuron activity in the submucous plexus, pointing to involvement of these neurons in the overall response to CT.
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Affiliation(s)
- Candice Fung
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Katerina Koussoulas
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Petra Unterweger
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Andrew M Allen
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia.,Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Joel C Bornstein
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Jaime P P Foong
- Department of Physiology, The University of Melbourne, Parkville, VIC, Australia
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26
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Koussoulas K, Swaminathan M, Fung C, Bornstein JC, Foong JPP. Neurally Released GABA Acts via GABA C Receptors to Modulate Ca 2+ Transients Evoked by Trains of Synaptic Inputs, but Not Responses Evoked by Single Stimuli, in Myenteric Neurons of Mouse Ileum. Front Physiol 2018; 9:97. [PMID: 29487540 PMCID: PMC5816811 DOI: 10.3389/fphys.2018.00097] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 01/29/2018] [Indexed: 12/16/2022] Open
Abstract
γ-Aminobutyric Acid (GABA) and its receptors, GABAA,B,C, are expressed in several locations along the gastrointestinal tract. Nevertheless, a role for GABA in enteric synaptic transmission remains elusive. In this study, we characterized the expression and function of GABA in the myenteric plexus of the mouse ileum. About 8% of all myenteric neurons were found to be GABA-immunoreactive (GABA+) including some Calretinin+ and some neuronal nitric oxide synthase (nNOS+) neurons. We used Wnt1-Cre;R26R-GCaMP3 mice, which express a genetically encoded fluorescent calcium indicator in all enteric neurons and glia. Exogenous GABA increased the intracellular calcium concentration, [Ca2+]i of some myenteric neurons including many that did not express GABA or nNOS (the majority), some GABA+, Calretinin+ or Neurofilament-M (NFM)+ but rarely nNOS+ neurons. GABA+ terminals contacted a significantly larger proportion of the cell body surface area of Calretinin+ neurons than of nNOS+ neurons. Numbers of neurons with GABA-induced [Ca2+]i transients were reduced by GABAA,B,C and nicotinic receptor blockade. Electrical stimulation of interganglionic fiber tracts was used to examine possible effects of endogenous GABA release. [Ca2+]i transients evoked by single pulses were unaffected by specific antagonists for each of the 3 GABA receptor subtypes. [Ca2+]i transients evoked by 20 pulse trains were significantly amplified by GABAC receptor blockade. These data suggest that GABAA and GABAB receptors are not involved in synaptic transmission, but suggest a novel role for GABAC receptors in modulating slow synaptic transmission, as indicated by changes in [Ca2+]i transients, within the ENS.
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Affiliation(s)
| | | | | | | | - Jaime P. P. Foong
- Department of Physiology, University of Melbourne, Parkville, VIC, Australia
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27
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Hibberd TJ, Travis L, Wiklendt L, Costa M, Brookes SJH, Hu H, Keating DJ, Spencer NJ. Synaptic activation of putative sensory neurons by hexamethonium-sensitive nerve pathways in mouse colon. Am J Physiol Gastrointest Liver Physiol 2018; 314:G53-G64. [PMID: 28935683 DOI: 10.1152/ajpgi.00234.2017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The gastrointestinal tract contains its own independent population of sensory neurons within the gut wall. These sensory neurons have been referred to as intrinsic primary afferent neurons (IPANs) and can be identified by immunoreactivity to calcitonin gene-related peptide (CGRP) in mice. A common feature of IPANs is a paucity of fast synaptic inputs observed during sharp microelectrode recordings. Whether this is observed using different recording techniques is of particular interest for understanding the physiology of these neurons and neural circuit modeling. Here, we imaged spontaneous and evoked activation of myenteric neurons in isolated whole preparations of mouse colon and correlated recordings with CGRP and nitric oxide synthase (NOS) immunoreactivity, post hoc. Calcium indicator fluo 4 was used for this purpose. Calcium responses were recorded in nerve cell bodies located 5-10 mm oral to transmural electrical nerve stimuli. A total of 618 recorded neurons were classified for CGRP or NOS immunoreactivity. Aboral electrical stimulation evoked short-latency calcium transients in the majority of myenteric neurons, including ~90% of CGRP-immunoreactive Dogiel type II neurons. Activation of Dogiel type II neurons had a time course consistent with fast synaptic transmission and was always abolished by hexamethonium (300 μM) and by low-calcium Krebs solution. The nicotinic receptor agonist 1,1-dimethyl-4-phenylpiperazinium iodide (during synaptic blockade) directly activated Dogiel type II neurons. The present study suggests that murine colonic Dogiel type II neurons receive prominent fast excitatory synaptic inputs from hexamethonium-sensitive neural pathways. NEW & NOTEWORTHY Myenteric neurons in isolated mouse colon were recorded using calcium imaging and then neurochemically defined. Short-latency calcium transients were detected in >90% of calcitonin gene-related peptide-immunoreactive neurons to electrical stimulation of hexamethonium-sensitive pathways. Putative sensory Dogiel type II calcitonin gene-related peptide-immunoreactive myenteric neurons may receive widespread fast synaptic inputs in mouse colon.
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Affiliation(s)
- Timothy J Hibberd
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University , Adelaide South Australia
| | - Lee Travis
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University , Adelaide South Australia
| | - Lukasz Wiklendt
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University , Adelaide South Australia
| | - Marcello Costa
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University , Adelaide South Australia
| | - Simon J H Brookes
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University , Adelaide South Australia
| | - Hongzhen Hu
- Department of Anesthesiology, Washington University , Saint Louis, Missouri
| | - Damien J Keating
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University , Adelaide South Australia
| | - Nick J Spencer
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University , Adelaide South Australia
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28
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Boesmans W, Hao MM, Vanden Berghe P. Optogenetic and chemogenetic techniques for neurogastroenterology. Nat Rev Gastroenterol Hepatol 2018; 15:21-38. [PMID: 29184183 DOI: 10.1038/nrgastro.2017.151] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Optogenetics and chemogenetics comprise a wide variety of applications in which genetically encoded actuators and indicators are used to modulate and monitor activity with high cellular specificity. Over the past 10 years, development of these genetically encoded tools has contributed tremendously to our understanding of integrated physiology. In concert with the continued refinement of probes, strategies to target transgene expression to specific cell types have also made much progress in the past 20 years. In addition, the successful implementation of optogenetic and chemogenetic techniques thrives thanks to ongoing advances in live imaging microscopy and optical technology. Although innovation of optogenetic and chemogenetic methods has been primarily driven by researchers studying the central nervous system, these techniques also hold great promise to boost research in neurogastroenterology. In this Review, we describe the different classes of tools that are currently available and give an overview of the strategies to target them to specific cell types in the gut wall. We discuss the possibilities and limitations of optogenetic and chemogenetic technology in the gut and provide an overview of their current use, with a focus on the enteric nervous system. Furthermore, we suggest some experiments that can advance our understanding of how the intrinsic and extrinsic neural networks of the gut control gastrointestinal function.
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Affiliation(s)
- Werend Boesmans
- Laboratory for Enteric Neuroscience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Herestraat 49, O&N 1 Box 701, 3000 Leuven, Belgium.,Department of Pathology, Maastricht University Medical Center, P. Debeijelaan 25, 6229 HX, Maastricht, The Netherlands
| | - Marlene M Hao
- Laboratory for Enteric Neuroscience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Herestraat 49, O&N 1 Box 701, 3000 Leuven, Belgium.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Pieter Vanden Berghe
- Laboratory for Enteric Neuroscience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Herestraat 49, O&N 1 Box 701, 3000 Leuven, Belgium
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29
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Fung C, Boesmans W, Cirillo C, Foong JPP, Bornstein JC, Vanden Berghe P. VPAC Receptor Subtypes Tune Purinergic Neuron-to-Glia Communication in the Murine Submucosal Plexus. Front Cell Neurosci 2017; 11:118. [PMID: 28487635 PMCID: PMC5403822 DOI: 10.3389/fncel.2017.00118] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 04/10/2017] [Indexed: 12/20/2022] Open
Abstract
The enteric nervous system (ENS) situated within the gastrointestinal tract comprises an intricate network of neurons and glia which together regulate intestinal function. The exact neuro-glial circuitry and the signaling molecules involved are yet to be fully elucidated. Vasoactive intestinal peptide (VIP) is one of the main neurotransmitters in the gut, and is important for regulating intestinal secretion and motility. However, the role of VIP and its VPAC receptors within the enteric circuitry is not well understood. We investigated this in the submucosal plexus of mouse jejunum using calcium (Ca2+)-imaging. Local VIP application induced Ca2+-transients primarily in neurons and these were inhibited by VPAC1- and VPAC2-antagonists (PG 99-269 and PG 99-465 respectively). These VIP-evoked neural Ca2+-transients were also inhibited by tetrodotoxin (TTX), indicating that they were secondary to action potential generation. Surprisingly, VIP induced Ca2+-transients in glia in the presence of the VPAC2 antagonist. Further, selective VPAC1 receptor activation with the agonist ([K15, R16, L27]VIP(1-7)/GRF(8-27)) predominantly evoked glial responses. However, VPAC1-immunoreactivity did not colocalize with the glial marker glial fibrillary acidic protein (GFAP). Rather, VPAC1 expression was found on cholinergic submucosal neurons and nerve fibers. This suggests that glial responses observed were secondary to neuronal activation. Trains of electrical stimuli were applied to fiber tracts to induce endogenous VIP release. Delayed glial responses were evoked when the VPAC2 antagonist was present. These findings support the presence of an intrinsic VIP/VPAC-initiated neuron-to-glia signaling pathway. VPAC1 agonist-evoked glial responses were inhibited by purinergic antagonists (PPADS and MRS2179), thus demonstrating the involvement of P2Y1 receptors. Collectively, we showed that neurally-released VIP can activate neurons expressing VPAC1 and/or VPAC2 receptors to modulate purine-release onto glia. Selective VPAC1 activation evokes a glial response, whereas VPAC2 receptors may act to inhibit this response. Thus, we identified a component of an enteric neuron-glia circuit that is fine-tuned by endogenous VIP acting through VPAC1- and VPAC2-mediated pathways.
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Affiliation(s)
- Candice Fung
- Department of Physiology, The University of MelbourneParkville, VIC, Australia.,Laboratory for Enteric Neuroscience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), KU LeuvenLeuven, Belgium
| | - Werend Boesmans
- Laboratory for Enteric Neuroscience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), KU LeuvenLeuven, Belgium
| | - Carla Cirillo
- Laboratory for Enteric Neuroscience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), KU LeuvenLeuven, Belgium
| | - Jaime P P Foong
- Department of Physiology, The University of MelbourneParkville, VIC, Australia
| | - Joel C Bornstein
- Department of Physiology, The University of MelbourneParkville, VIC, Australia
| | - Pieter Vanden Berghe
- Laboratory for Enteric Neuroscience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), KU LeuvenLeuven, Belgium
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Shanks J, Herring N, Johnson E, Liu K, Li D, Paterson DJ. Overexpression of Sarcoendoplasmic Reticulum Calcium ATPase 2a Promotes Cardiac Sympathetic Neurotransmission via Abnormal Endoplasmic Reticulum and Mitochondria Ca 2+ Regulation. Hypertension 2017; 69:625-632. [PMID: 28223472 PMCID: PMC5344179 DOI: 10.1161/hypertensionaha.116.08507] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 10/11/2016] [Accepted: 01/18/2017] [Indexed: 12/18/2022]
Abstract
Supplemental Digital Content is available in the text. Reduced cardiomyocyte excitation–contraction coupling and downregulation of the SERCA2a (sarcoendoplasmic reticulum calcium ATPase 2a) is associated with heart failure. This has led to viral transgene upregulation of SERCA2a in cardiomyocytes as a treatment. We hypothesized that SERCA2a gene therapy expressed under a similar promiscuous cytomegalovirus promoter could also affect the cardiac sympathetic neural axis and promote sympathoexcitation. Stellate neurons were isolated from 90 to 120 g male, Sprague–Dawley, Wistar Kyoto, and spontaneously hypertensive rats. Neurons were infected with Ad-mCherry or Ad-mCherry-hATP2Aa (SERCA2a). Intracellular Ca2+ changes were measured using fura-2AM in response to KCl, caffeine, thapsigargin, and carbonylcyanide-p-trifluoromethoxyphenylhydrazine to mobilize intracellular Ca2+ stores. The effect of SERCA2a on neurotransmitter release was measured using [3H]-norepinephrine overflow from 340 to 360 g Sprague–Dawley rat atria in response to right stellate ganglia stimulation. Upregulation of SERCA2a resulted in greater neurotransmitter release in response to stellate stimulation compared with control (empty: 98.7±20.5 cpm, n=7; SERCA: 186.5±28.41 cpm, n=8; P<0.05). In isolated Sprague–Dawley rat stellate neurons, SERCA2a overexpression facilitated greater depolarization-induced Ca2+ transients (empty: 0.64±0.03 au, n=57; SERCA: 0.75±0.03 au, n=68; P<0.05), along with increased endoplasmic reticulum and mitochondria Ca2+ load. Similar results were observed in Wistar Kyoto and age-matched spontaneously hypertensive rats, despite no further increase in endoplasmic reticulum load being observed in the spontaneously hypertensive rat (spontaneously hypertensive rats: empty, 0.16±0.04 au, n=18; SERCA: 0.17±0.02 au, n=25). In conclusion, SERCA2a upregulation in cardiac sympathetic neurons resulted in increased neurotransmission and increased Ca2+ loading into intracellular stores. Whether the increased Ca2+ transient and neurotransmission after SERCA2A overexpression contributes to enhanced sympathoexcitation in heart failure patients remains to be determined.
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Affiliation(s)
- Julia Shanks
- From the Department of Physiology, Anatomy and Genetics, Burdon Sanderson Cardiac Science Centre and BHF Centre of Research Excellence, Oxford, United Kingdom (J.S., N.H., K.L., D.L., D.J.P.); and Sir William Dunn School of Pathology, Oxford, United Kingdom (E.J.)
| | - Neil Herring
- From the Department of Physiology, Anatomy and Genetics, Burdon Sanderson Cardiac Science Centre and BHF Centre of Research Excellence, Oxford, United Kingdom (J.S., N.H., K.L., D.L., D.J.P.); and Sir William Dunn School of Pathology, Oxford, United Kingdom (E.J.)
| | - Errin Johnson
- From the Department of Physiology, Anatomy and Genetics, Burdon Sanderson Cardiac Science Centre and BHF Centre of Research Excellence, Oxford, United Kingdom (J.S., N.H., K.L., D.L., D.J.P.); and Sir William Dunn School of Pathology, Oxford, United Kingdom (E.J.)
| | - Kun Liu
- From the Department of Physiology, Anatomy and Genetics, Burdon Sanderson Cardiac Science Centre and BHF Centre of Research Excellence, Oxford, United Kingdom (J.S., N.H., K.L., D.L., D.J.P.); and Sir William Dunn School of Pathology, Oxford, United Kingdom (E.J.)
| | - Dan Li
- From the Department of Physiology, Anatomy and Genetics, Burdon Sanderson Cardiac Science Centre and BHF Centre of Research Excellence, Oxford, United Kingdom (J.S., N.H., K.L., D.L., D.J.P.); and Sir William Dunn School of Pathology, Oxford, United Kingdom (E.J.)
| | - David J Paterson
- From the Department of Physiology, Anatomy and Genetics, Burdon Sanderson Cardiac Science Centre and BHF Centre of Research Excellence, Oxford, United Kingdom (J.S., N.H., K.L., D.L., D.J.P.); and Sir William Dunn School of Pathology, Oxford, United Kingdom (E.J.).
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31
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Advanced 3D Optical Microscopy in ENS Research. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 891:193-9. [DOI: 10.1007/978-3-319-27592-5_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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32
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Boesmans W, Hao MM, Vanden Berghe P. Optical Tools to Investigate Cellular Activity in the Intestinal Wall. J Neurogastroenterol Motil 2015; 21:337-51. [PMID: 26130630 PMCID: PMC4496899 DOI: 10.5056/jnm15096] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 06/10/2015] [Indexed: 12/13/2022] Open
Abstract
Live imaging has become an essential tool to investigate the coordinated activity and output of cellular networks. Within the last decade, 2 Nobel prizes have been awarded to recognize innovations in the field of imaging: one for the discovery, use, and optimization of the green fluorescent protein (2008) and the second for the development of super-resolved fluorescence microscopy (2014). New advances in both optogenetics and microscopy now enable researchers to record and manipulate activity from specific populations of cells with better contrast and resolution, at higher speeds, and deeper into live tissues. In this review, we will discuss some of the recent developments in microscope technology and in the synthesis of fluorescent probes, both synthetic and genetically encoded. We focus on how live imaging of cellular physiology has progressed our understanding of the control of gastrointestinal motility, and we discuss the hurdles to overcome in order to apply the novel tools in the field of neurogastroenterology and motility.
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Affiliation(s)
- Werend Boesmans
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for GastroIntestinal Disorders (TARGID), Department of Clinical and Experimental Medicine, University of Leuven, Leuven, Belgium
| | - Marlene M Hao
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for GastroIntestinal Disorders (TARGID), Department of Clinical and Experimental Medicine, University of Leuven, Leuven, Belgium
| | - Pieter Vanden Berghe
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for GastroIntestinal Disorders (TARGID), Department of Clinical and Experimental Medicine, University of Leuven, Leuven, Belgium
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Lowette K, Tack J, Vanden Berghe P. Role of corticosterone in the murine enteric nervous system during fasting. Am J Physiol Gastrointest Liver Physiol 2014; 307:G905-13. [PMID: 25214399 PMCID: PMC4216992 DOI: 10.1152/ajpgi.00233.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Food intake depends on a tightly controlled interplay of appetite hormones and the enteric (ENS) and central nervous system. Corticosterone (CORT) levels, which are mainly studied with regard to stress, are also increased during fasting. However, the role of CORT in the ENS remains elusive. Therefore, we investigated whether CORT modulates activity of enteric neurons and whether its intracellular regulator, 11β-hydroxysteroid dehydrogenase (HSD) type 1, is present in the myenteric plexus, using immunohistochemistry and RT-qPCR. Effects of CORT on neuronal activity and expression of neuronal markers in the myenteric plexus were assessed via Ca(2+) imaging and RT-qPCR, respectively, whereas modulations in mixing behavior were measured by video imaging. 11β-HSD-1 was present in enteric neurons along the gastrointestinal tract, and its expression increased after fasting (control: 0.58 ± 0.09 vs. fasted: 1.5 ± 0.23; P < 0.05). CORT incubation significantly reduced neuronal Ca(2+) transients in tissues stimulated by electrical pulses (control: 1.31 ± 0.01 vs. CORT: 1.27 ± 0.01, P < 0.01) and in cultured neurons (control: 1.85 ± 0.03 vs. CORT: 1.76 ± 0.03, P < 0.05). CORT decreased small intestinal mixing (P < 0.05). Incubation of muscle myenteric plexus preparations with CORT induced an increase in cannabinoid receptor 1 (CB1, P < 0.05) and synaptobrevin (P < 0.05) but not in 11β-HSD-1 mRNA expression. In addition, fasting induced significant elevations in synaptobrevin (P < 0.05) and CB1 (P < 0.01) mRNA expression. In conclusion, we suggest CORT to be a downstream factor in a feeding state-related pathway that modulates important proteins in the fine tuning of enteric neurotransmission and gastrointestinal motility.
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Affiliation(s)
- Katrien Lowette
- 1Laboratory for Enteric NeuroScience, University of Leuven, Leuven, Belgium; and ,2Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | - Jan Tack
- 2Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | - Pieter Vanden Berghe
- Laboratory for Enteric NeuroScience, University of Leuven, Leuven, Belgium; and Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
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Analysis of spontaneous and nerve-evoked calcium transients in intact extraocular muscles in vitro. Exp Eye Res 2012; 100:73-85. [PMID: 22579493 DOI: 10.1016/j.exer.2012.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Revised: 03/29/2012] [Accepted: 04/18/2012] [Indexed: 12/22/2022]
Abstract
Extraocular muscles (EOMs) have unique calcium handling properties, yet little is known about the dynamics of calcium events underlying ultrafast and tonic contractions in myofibers of intact EOMs. Superior oblique EOMs of juvenile chickens were dissected with their nerve attached, maintained in oxygenated Krebs buffer, and loaded with fluo-4. Spontaneous and nerve stimulation-evoked calcium transients were recorded and, following calcium imaging, some EOMs were double-labeled with rhodamine-conjugated alpha-bungarotoxin (rhBTX) to identify EOM myofiber types. EOMs showed two main types of spontaneous calcium transients, one slow type (calcium waves with 1/2(max) duration of 2-12 s, velocity of 25-50 μm/s) and two fast "flash-like" types (Type 1, 30-90 ms; Type 2, 90-150 ms 1/2(max) duration). Single pulse nerve stimulation evoked fast calcium transients identical to the fast (Type 1) calcium transients. Calcium waves were accompanied by a local myofiber contraction that followed the calcium transient wavefront. The magnitude of calcium-wave induced myofiber contraction far exceeded those of movement induced by nerve stimulation and associated fast calcium transients. Tetrodotoxin eliminated nerve-evoked transients, but not spontaneous transients. Alpha-bungarotoxin eliminated both spontaneous and nerve-evoked fast calcium transients, but not calcium waves, and caffeine increased wave activity. Calcium waves were observed in myofibers lacking spontaneous or evoked fast transients, suggestive of multiply-innervated myofibers, and this was confirmed by double-labeling with rhBTX. We propose that the abundant spontaneous calcium transients and calcium waves with localized contractions that do not depend on innervation may contribute to intrinsic generation of tonic functions of EOMs.
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Bayguinov PO, Broadhead MJ, Okamoto T, Hennig GW, Smith TK. Activity in varicosities within the myenteric plexus between and during the colonic migrating motor complex in the isolated murine large intestine. Neurogastroenterol Motil 2012; 24:e185-201. [PMID: 22332643 PMCID: PMC4856478 DOI: 10.1111/j.1365-2982.2012.01892.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Neuronal communication within the myenteric plexus occurs when action potentials along nerve fibers produce Ca(2+) transients in varicosities leading to exocytosis of vesicles and neurotransmitters release. We used Ca(2+) transients in varicosities to monitor action potential activity in myenteric nerve pathways both between and during the colonic migrating motor complex (CMMC) in the isolated murine colon. METHODS Strips of longitudinal muscle were removed to reveal the myenteric ganglia, which were then loaded with Fluo-4. KEY RESULTS Many varicosities, including synaptotagmin 1 labeled varicosities, exhibited ongoing Ca(2+) transients (duration of unitary Ca(2+) transient 3.9 s). Between CMMCs, varicosities fired at a frequency of 0.6 Hz, which correlated with spontaneous inhibitory junction potentials in the circular muscle, suggesting they were mainly in inhibitory nerve pathways. During a CMMC other previously quiescent varicosities fired at 1.3 Hz (max. 2.0 Hz) for the duration (24 s) of the CMMC, suggesting they were on excitatory nerve pathways. Activity in varicosities was correlated with Ca(2+) transient responses in a number of neurons. Some varicosities appeared to release an inhibitory neurotransmitter that reduced activity in nNOS-positive neurons. Varicosities along the same nerve fiber exhibited identical patterns of activity that allowed nerve fibers to be traced throughout the myenteric plexus and internodal strands. Activity in varicosities was reduced by hexamethonium (100 μmol L(-1) ), and blocked by ω-conotoxin GVIA (200 nM) and tetrodotoxin (1 μmol L(-1) ; TTX). CONCLUSIONS & INFERENCES Ca(2+) imaging of varicosities allows for a determination of activity in neural pathways within the enteric nervous system.
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Affiliation(s)
- P O Bayguinov
- Department of Cell Biology and Physiology, University of Nevada School of Medicine, Reno, NV, USA
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Filiou MD, Zhang Y, Teplytska L, Reckow S, Gormanns P, Maccarrone G, Frank E, Kessler MS, Hambsch B, Nussbaumer M, Bunck M, Ludwig T, Yassouridis A, Holsboer F, Landgraf R, Turck CW. Proteomics and metabolomics analysis of a trait anxiety mouse model reveals divergent mitochondrial pathways. Biol Psychiatry 2011; 70:1074-82. [PMID: 21791337 DOI: 10.1016/j.biopsych.2011.06.009] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 06/07/2011] [Accepted: 06/07/2011] [Indexed: 01/06/2023]
Abstract
BACKGROUND Although anxiety disorders are the most prevalent psychiatric disorders, no molecular biomarkers exist for their premorbid diagnosis, accurate patient subcategorization, or treatment efficacy prediction. To unravel the neurobiological underpinnings and identify candidate biomarkers and affected pathways for anxiety disorders, we interrogated the mouse model of high anxiety-related behavior (HAB), normal anxiety-related behavior (NAB), and low anxiety-related behavior (LAB) employing a quantitative proteomics and metabolomics discovery approach. METHODS We compared the cingulate cortex synaptosome proteomes of HAB and LAB mice by in vivo (15)N metabolic labeling and mass spectrometry and quantified the cingulate cortex metabolomes of HAB/NAB/LAB mice. The combined data sets were used to identify divergent protein and metabolite networks by in silico pathway analysis. Selected differentially expressed proteins and affected pathways were validated with immunochemical and enzymatic assays. RESULTS Altered levels of up to 300 proteins and metabolites were found between HAB and LAB mice. Our data reveal alterations in energy metabolism, mitochondrial import and transport, oxidative stress, and neurotransmission, implicating a previously nonhighlighted role of mitochondria in modulating anxiety-related behavior. CONCLUSIONS Our results offer insights toward a molecular network of anxiety pathophysiology with a focus on mitochondrial contribution and provide the basis for pinpointing affected pathways in anxiety-related behavior.
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Affiliation(s)
- Michaela D Filiou
- Max Planck Institute of Psychiatry, Kraepelinstrasse 2, Munich, Germany
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Michel K, Michaelis M, Mazzuoli G, Mueller K, Vanden Berghe P, Schemann M. Fast calcium and voltage-sensitive dye imaging in enteric neurones reveal calcium peaks associated with single action potential discharge. J Physiol 2011; 589:5941-7. [PMID: 22041184 DOI: 10.1113/jphysiol.2011.219550] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Slow changes in [Ca(2+)](i) reflect increased neuronal activity. Our study demonstrates that single-trial fast [Ca(2+)](i) imaging (≥200 Hz sampling rate) revealed peaks each of which are associated with single spike discharge recorded by consecutive voltage-sensitive dye (VSD) imaging in enteric neurones and nerve fibres. Fast [Ca(2+)](i) imaging also revealed subthreshold fast excitatory postsynaptic potentials. Nicotine-evoked [Ca(2+)](i) peaks were reduced by -conotoxin and blocked by ruthenium red or tetrodotoxin. Fast [Ca(2+)](i) imaging can be used to directly record single action potentials in enteric neurones. [Ca(2+)](i) peaks required opening of voltage-gated sodium and calcium channels as well as Ca(2+) release from intracellular stores.
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Affiliation(s)
- K Michel
- Human Biology, Technische Universität München, Freising, Germany
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Naidoo V, Dai X, Galligan JJ. R-type Ca(2+) channels contribute to fast synaptic excitation and action potentials in subsets of myenteric neurons in the guinea pig intestine. Neurogastroenterol Motil 2010; 22:e353-63. [PMID: 20879993 DOI: 10.1111/j.1365-2982.2010.01596.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND R-type Ca(2+) channels are expressed by myenteric neurons in the guinea pig ileum but the specific function of these channels is unknown. METHODS In the present study, we used intracellular electrophysiological techniques to determine the function of R-type Ca(2+) channels in myenteric neurons in the acutely isolated longitudinal musclemyenteric plexus. We used immunohistochemical methods to localize the Ca(V)2.3 subunit of the R-type Ca(2+) channel in myenteric neurons. We also studied the effects of the non-selective Ca(2+) channel antagonist, CdCl₂ (100 μmol L⁻¹), the R-type Ca(2+) channel blockers NiCl₂ (50 μmol L⁻¹) and SNX-482 (0.1 μmol L⁻¹), and the N-type Ca(2+) channel blocker x-conotoxin GVIA (CTX 0.1 μmol L⁻¹) on action potentials and fast and slow excitatory postsynaptic potentials (fEPSPs and sEPSPs) in S and AH neurons in vitro. KEY RESULTS Ca(V)2.3 co-localized with calretinin and calbindin in myenteric neurons. NiCl₂ and SNX-482 reduced the duration and amplitude of action potentials in AH but not S neurons. NiCl₂ inhibited the afterhyperpolarization in AH neurons. x-conotoxin GVIA, but not NiCl₂, blocked sEPSPs in AH neurons. NiCl₂ and SNX-482 inhibited cholinergic, but not cholinergic/purinergic, fEPSPs in S neurons. CONCLUSIONS AND INFERENCES These data show that R-type Ca(2+) channels contribute to action potentials, but not slow synaptic transmission, in AH neurons. R-type Ca(2+) channels contribute to release of acetylcholine as the mediator of fEPSPs in some S neurons. These data indicate that R-type Ca(2+) channels may be a target for drugs that selectively modulate activity of AH neurons or could alter fast synaptic excitation in specific pathways in the myenteric plexus.
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Affiliation(s)
- V Naidoo
- Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA
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Heredia DJ, Dickson EJ, Bayguinov PO, Hennig GW, Smith TK. Colonic elongation inhibits pellet propulsion and migrating motor complexes in the murine large bowel. J Physiol 2010; 588:2919-34. [PMID: 20547675 DOI: 10.1113/jphysiol.2010.191445] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The colonic migrating motor complex (CMMC) is a rhythmically occurring neurally mediated motor pattern. Although the CMMC spontaneously propagates along an empty colon it is responsible for faecal pellet propulsion in the murine large bowel. Unlike the peristaltic reflex, the CMMC is an 'all or none' event that appears to be dependent upon Dogiel Type II/AH neurons for its regenerative slow propagation down the colon. A reduction in the amplitude of CMMCs or an elongated colon have both been thought to underlie slow transit constipation, although whether these phenomena are related has not been considered. In this study we examined the mechanisms by which colonic elongation might affect the CMMC using video imaging of the colon, tension and electrophysiological recordings from the muscle and Ca(2+) imaging of myenteric neurons. As faecal pellets were expelled from the murine colon, it shortened by up to 29%. Elongation of the colon resulted in a linear reduction in the velocity of a faecal pellet and the amplitude of spontaneous CMMCs. Elongation of the oral end of a colonic segment reduced the amplitude of CMMCs, whereas elongation of the anal end of the colon evoked a premature CMMC, and caused the majority of CMMCs to propagate in an anal to oral direction. Dogiel Type II/AH sensory neurons and most other myenteric neurons responded to oral elongation with reduced amplitude and frequency of spontaneous Ca(2+) transients, whereas anal elongation increased their amplitude and frequency in most neurons. The inhibitory effects of colonic elongation were reduced by blocking nitric oxide (NO) production with l-NA (100 mum) and soluble guanylate cyclase with 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10 mum); whereas, l-arginine (1-2 mm) enhanced the inhibitory effects of colonic elongation. In conclusion, polarized neural reflexes can be triggered by longitudinal stretch. The dominant effect of elongation is to reduce CMMCs primarily by inhibiting Dogiel Type II/AH neurons, thus facilitating colonic accommodation and slow transit.
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Affiliation(s)
- Dante J Heredia
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA.
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Bayguinov PO, Hennig GW, Smith TK. Calcium activity in different classes of myenteric neurons underlying the migrating motor complex in the murine colon. J Physiol 2009; 588:399-421. [PMID: 19948652 DOI: 10.1113/jphysiol.2009.181172] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The spontaneous colonic migrating motor complex (CMMC) is a cyclical contractile and electrical event that is the primary motor pattern underlying fecal pellet propulsion along the murine colon. We have combined Ca(2+) imaging with immunohistochemistry to determine the role of different classes of myenteric neurons during the CMMC. Between CMMCs, myenteric neurons usually displayed ongoing but uncoordinated activity. Stroking the mucosa at the oral or anal end of the colon resulted in a CMMC (latency: 6 to 10 s; duration: 28 s) that consisted of prolonged increases in activity in many myenteric neurons that was correlated to Ca(2+) transients in and displacement of the muscle. These neurons were likely excitatory motor neurons. Activity in individual neurons during the CMMC was similar regardless of whether the CMMC occurred spontaneously or was evoked by anal or oral mucosal stimulation. This suggests that convergent interneuronal pathways exist which generate CMMCs. Interestingly, Ca(2+) transients in a subset of NOS +ve neurons were substantially reduced during the CMMC. These neurons are likely to be inhibitory motor neurons that reduce their activity during a complex (disinhibition) to allow full excitation of the muscle. Local stimulation of the mucosa evoked synchronized Ca(2+) transients in Dogiel Type II (mitotracker/calbindin-positive) neurons after a short delay (1-2 s), indicating they were the sensory neurons underlying the CMMC. These local responses were observed in hexamethonium, but were blocked by ondansetron (5-HT(3) antagonist), suggesting Dogiel Type II neurons were activated by 5-HT release from enterochromaffin cells in the mucosa. In fact, removal of the mucosa yielded no spontaneous CMMCs, although many neurons (NOS +ve and NOS ve) exhibited ongoing activity, including Dogiel Type II neurons. These results suggest that spontaneous or evoked 5-HT release from the mucosa is necessary for the activation of Dogiel Type II neurons that generate CMMCs.
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Affiliation(s)
- Peter O Bayguinov
- Department of Physiology and Cell Biology, Anderson Medical Sciences Building/352, University of Nevada School of Medicine, Reno, NV 89557, USA
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Abstract
Advances in knowledge of enteric neurons electrophysiological characteristics have led to the realisation that the properties of the neurons are dependent on the state of the intestine, the region, the method of recording and the species. Thus, under different experimental conditions, electrophysiological studies cannot provide a reliable signature that identifies the functional type of neuron. In the normal guinea-pig small intestine, taken as a model tissue, neurons can be separated into two electrophysiological groups, S and AH neurons. Combined morphological and physiological studies place several classes of motor and interneurons in the S group, and intrinsic primary afferent neurons in the AH group. There is some evidence for subgroups of S neurons, in which electrophysiological differences are correlated with functional subtypes, but these subgroups have been incompletely investigated. Morphologically characterized Dogiel type II (DII) neurons are recognisable in many species, from mouse to human, but their electrophysiological characteristics are only partly conserved across species or cannot be satisfactorily defined due to technical difficulties. There is a strong need for a comprehensive analysis of channels and currents of S/Dogiel type I neuron subtypes, similar to the comprehensive analysis of AH/DII neurons in the guinea-pig, and similar studies need to be conducted in human and other species. The purpose of this review is to highlight that criteria used for electrophysiological definition of enteric neurons might not be sufficient to distinguish between functional classes of neurons, due to intrinsic properties of neuronal subpopulations, plasticity in pathological conditions and differences in recording techniques.
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Affiliation(s)
- K Nurgali
- Department of Physiology, University of Melbourne, Australia.
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42
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Paradoxical sleep deprivation impairs spatial learning and affects membrane excitability and mitochondrial protein in the hippocampus. Brain Res 2008; 1230:224-32. [DOI: 10.1016/j.brainres.2008.07.033] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 07/09/2008] [Accepted: 07/09/2008] [Indexed: 11/22/2022]
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Vanden Berghe P, Tack J, Boesmans W. Highlighting synaptic communication in the enteric nervous system. Gastroenterology 2008; 135:20-3. [PMID: 18555020 DOI: 10.1053/j.gastro.2008.06.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Smith TK, Spencer NJ, Hennig GW, Dickson EJ. Recent advances in enteric neurobiology: mechanosensitive interneurons. Neurogastroenterol Motil 2007; 19:869-78. [PMID: 17988274 DOI: 10.1111/j.1365-2982.2007.01019.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Until recently, it was generally assumed that the only intrinsic sensory neuron, or primary afferent neuron, in the gut was the after-hyperpolarizing AH/Type II neuron. AH neurons excited by local chemical and mechanical stimulation of the mucosa appear to be necessary for activating the peristaltic reflex (oral excitation and anal inhibition of the muscle layers) and anally propagating ring like contractions (peristaltic waves) that depend upon smooth muscle tone. However, our recent findings in the guinea-pig distal colon suggest that different neurochemical classes of interneuron in the colon are also mechanosensitive in that they respond directly to changes in muscle length, rather than muscle tone or tension. These interneurons have electrophysiological properties consistent with myenteric S-neurons. Ascending and descending interneurons respond directly to circumferential stretch by generating an ongoing polarized peristaltic reflex activity (oral excitatory and anal inhibitory junction potentials) in the muscle for as long as the stimulus is maintained. Some descending (nitric oxide synthase +ve) interneurons, on the other hand, appear to respond directly to longitudinal stretch and are involved in accommodation and slow transit of faecal pellets down the colon. This review will present recent evidence that suggests some myenteric S interneurons, in addition to AH neurons, behave as intrinsic sensory neurons.
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Affiliation(s)
- T K Smith
- Department of Physiology & Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA.
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Abstract
Alpha2-adrenoceptors inhibit Ca2+ influx through voltage-gated Ca2+ channels throughout the nervous system and Ca2+ channel function is modulated following activation of some G-protein coupled receptors. We studied the specific Ca2+ channel inhibited following alpha2-adrenoceptor activation in guinea-pig small intestinal myenteric neurons. Ca2+ currents (I(Ca2+)) were studied using whole-cell patch-clamp techniques. Changes in intracellular Ca2+ (delta[Ca2+]i) in nerve cell bodies and varicosities were studied using digital imaging where Ca2+ influx was evoked by KCl (60 mmol L(-1)) depolarization. The alpha2-adrenoceptor agonist, UK 14 304 (0.01-1 micromol L(-1)) inhibited I(Ca2+) and delta[Ca2+]i; maximum inhibition of I(Ca2+) was 40%. UK 14 304 did not affect I(Ca2+) in the presence of SNX-482 or NiCl2 (R-type Ca2+ channel antagonists). UK 14 304 inhibited I(Ca2+) in the presence of nifedipine, omega-agatoxin IVA or omega-conotoxin, inhibitors of L-, P/Q- and N-type Ca2+ channels. UK 14 304 induced inhibition of I(Ca2+) was blocked by pertussis toxin pretreatment (1 microg mL(-1) for 2 h). Alpha2-adrenoceptors couple to inhibition of R-type Ca2+ channels via a pertussis toxin-sensitive pathway in myenteric neurons. R-type channels may be a target for the inhibitory actions of noradrenaline released from sympathetic nerves on to myenteric neurons.
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Affiliation(s)
- X Bian
- Department of Pharmacology and Toxicology and the Neuroscience Program, Michigan State University, East Lansing, MI 48823, USA
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Vanden Berghe P, Klingauf J. Spatial organization and dynamic properties of neurotransmitter release sites in the enteric nervous system. Neuroscience 2007; 145:88-99. [PMID: 17197103 DOI: 10.1016/j.neuroscience.2006.11.048] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2006] [Revised: 11/15/2006] [Accepted: 11/15/2006] [Indexed: 10/23/2022]
Abstract
Synaptic communication requires an efficient coupling of vesicle fusion to release neurotransmitter and vesicle retrieval to repopulate the synapse. In synapses of the CNS many proteins involved in exocytosis, endocytosis and refilling of vesicles have been identified. However, little is known about the organization and functioning of synaptic contacts in the enteric nervous system (ENS). We used fluorescent antibodies against presynaptic proteins (synaptobrevin, synaptophysin, synaptotagmin and bassoon) to identify synaptic contacts not only in guinea-pig enteric ganglia but also in the interconnecting fiber strands. Staining patterns were not altered by colchicine (100 microM), ruling out a contribution of protein transport at the time of fixation. Active release sites at fiber intersections and around neuronal cell bodies were labeled with FM1-43 (10 microM) by high K+ or electric field stimulation (EFS). During a second round of EFS, vesicles were reused, as reflected by dye loss. Destaining rates increased with stimulus frequency (2-30 Hz), reaching a maximum at about 15 Hz, likely caused by synaptic depression at higher frequencies. Tetrodotoxin (TTX, 1 microM) as well as nominally zero external Ca2+ (2 mM EGTA) prevented all destaining. The readily releasable pool (RRP, a subset of vesicles docked at the membrane and ready to fuse upon [Ca2+]i increase) can be specifically released by a hypertonic challenge (500 mM sucrose). We measured this pool to be approximately 27% of the total recycling pool, remarkably similar to synapses in the CNS. In whole-mount preparations, FM1-43 also reliably labeled active release sites in ganglia, fiber strands and in muscle bundles. The staining pattern indicated that the presynaptic antibodies mainly labeled active sites. The presence of numerous release sites suggests information processing capability within interconnecting fibers. With FM imaging, enteric synaptic function can be monitored independent of any postsynaptic modulation. Although electron microscopy data suggest that ENS synapses may not be as specialized as hippocampal synapses, remarkably similar release properties were measured.
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Affiliation(s)
- P Vanden Berghe
- Department of Membrane Biophysics, Max-Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077, Göttingen, Germany.
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Joseph EK, Levine JD. Mitochondrial electron transport in models of neuropathic and inflammatory pain. Pain 2006; 121:105-14. [PMID: 16472913 DOI: 10.1016/j.pain.2005.12.010] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Revised: 11/29/2005] [Accepted: 12/06/2005] [Indexed: 10/25/2022]
Abstract
Although peripheral nerve function is strongly dependent on energy stores, the role of the mitochondrial electron transport chain, which drives ATP synthesis, in peripheral pain mechanisms, has not been examined. In models of HIV/AIDS therapy (dideoxycytidine), cancer chemotherapy (vincristine), and diabetes (streptozotocin)-induced neuropathy, inhibitors of mitochondrial electron transport chain complexes I, II, III, IV, and V significantly attenuated neuropathic pain-related behavior in rats. While inhibitors of all five complexes also attenuated tumor necrosis factor alpha-induced hyperalgesia, they had no effect on hyperalgesia induced by prostaglandin E2 and epinephrine. Two competitive inhibitors of ATP-dependent mechanisms, adenosine 5'-(beta,gamma-imido) triphosphate and P1,P4-di(adenosine-5') tetraphosphate, attenuated dideoxycytidine, vincristine, and streptozotocin-induced hyperalgesia. Neither of these inhibitors, however, affected tumor necrosis factor alpha, prostaglandin E2 or epinephrine hyperalgesia. These experiments demonstrate a role of the mitochondrial electron transport chain in neuropathic and some forms of inflammatory pain. The contribution of the mitochondrial electron transport chain in neuropathic pain is ATP dependent.
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Affiliation(s)
- Elizabeth K Joseph
- Department of Medicine, Division of Neuroscience and Biomedical Sciences Program, University of California at San Francisco, 521 Parnassus Ave, Box # 0440/C522, San Francisco, CA 94143-0440, USA
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Hamodeh SA, Rehn M, Haschke G, Diener M. Mechanism of butyrate-induced hyperpolarization of cultured rat myenteric neurones. Neurogastroenterol Motil 2004; 16:597-604. [PMID: 15500516 DOI: 10.1111/j.1365-2982.2004.00545.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Short-chain fatty acids produced by the bacterial fermentation of carbohydrates are present in high concentrations within the colonic lumen and have been shown to alter the excitability of enteric neurones. The present study was designed to investigate the mechanisms of butyrate-induced changes in membrane potential of myenteric neurones. Myenteric neurones from 4-10-day-old rats were isolated from the small and large intestine by an enzymatic digestion with collagenase and kept in culture. Membrane potential was measured with the whole-cell patch-clamp technique and the intracellular Ca2+ concentration was measured with the fura-2 method. The short-chain fatty acid butyrate (10-100 mmol L(-1)) induced a reversible and concentration-dependent hyperpolarization of the membrane with a half-maximal effect at 30 mmol L(-1). The hyperpolarization evoked by butyrate (50 mmol L(-1)) was strongly inhibited by charybdotoxin (10(-7) mol L(-1)), a specific blocker of Ca2+ -dependent K+ channels. The butyrate-induced hyperpolarization was resistant against blockade of phospholipase C by U-73122 (10(-5) mol L(-1)), and resistant against inclusion of heparin (6 x 10(-6) mol L(-1)), an inositol-1,4,5-trisphosphate receptor antagonist, in the patch-pipette. In contrast, ruthenium red (3 x 10(-5) mol L(-1)), an inhibitor of ryanodine receptors, significantly reduced both the hyperpolarization of the membrane as well as the increase in the intracellular Ca2+ concentration evoked by butyrate. Even in neurones permeabilized with saponin (10 mg L(-1)), butyrate was able to stimulate a release of stored intracellular Ca2+ suggesting a direct action of the short-chain fatty acid at the stores without mediation of a soluble intracellular second messenger.
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Affiliation(s)
- S A Hamodeh
- Institute for Veterinary Physiology, University of Giessen, Giessen, Germany
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Furness JB, Jones C, Nurgali K, Clerc N. Intrinsic primary afferent neurons and nerve circuits within the intestine. Prog Neurobiol 2004; 72:143-64. [PMID: 15063530 DOI: 10.1016/j.pneurobio.2003.12.004] [Citation(s) in RCA: 268] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2003] [Accepted: 12/03/2003] [Indexed: 02/08/2023]
Abstract
Intrinsic primary afferent neurons (IPANs) of the enteric nervous system are quite different from all other peripheral neurons. The IPANs are transducers of physiological stimuli, including movement of the villi or distortion of the mucosa, contraction of intestinal muscle and changes in the chemistry of the contents of the gut lumen. They are the first neurons in intrinsic reflexes that influence the patterns of motility, secretion of fluid across the mucosal epithelium and local blood flow in the small and large intestines. In the guinea pig small intestine, where they have been characterized in detail, IPANs have Dogiel type II morphology, that is they are large round or oval neurons with multiple processes, some of which end close to the luminal surface of the intestine, and some of which form synapses with enteric interneurons, motor neurons and with other IPANs. The IPANs have well-defined ionic currents through which their excitability, and their functions in enteric nerve circuits, is determined. These include voltage-gated Na(+) and Ca(2+) currents, a long lasting calcium-activated K(+) current, and a hyperpolarization-activated cationic current. The IPANs exhibit long-term changes in their states of excitation that can be induced by extended periods of low frequency activity in synaptic inputs and by inflammatory mediators, either applied directly or released during an inflammatory challenge. The IPANs may be involved in pathological changes in enteric function following inflammation.
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Affiliation(s)
- John B Furness
- Department of Anatomy & Cell Biology and Centre for Neuroscience, University of Melbourne, Parkville, Vic. 3010, Australia.
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Barstow KL, Locknar SA, Merriam LA, Parsons RL. The modulation of action potential generation by calcium-induced calcium release is enhanced by mitochondrial inhibitors in mudpuppy parasympathetic neurons. Neuroscience 2004; 124:327-39. [PMID: 14980383 DOI: 10.1016/j.neuroscience.2003.12.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2003] [Revised: 12/05/2003] [Accepted: 12/11/2003] [Indexed: 11/29/2022]
Abstract
Previously, we demonstrated that outward currents activated by calcium-induced calcium release (CICR) opposed depolarization-induced action potential (AP) generation in dissociated mudpuppy parasympathetic neurons [J Neurophysiol 88 (2002) 1119]. In the present study, we tested whether AP generation by depolarizing current ramps could be altered by dissipating the mitochondrial membrane potential and thus interrupting mitochondrial Ca2+ buffering. Exposure to the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP; 2 microM) alone or in combination with the mitochondrial ATP synthase inhibitor oligomycin (8 microg/ml), increased the latency to AP generation. Exposure to the electron transport chain inhibitor rotenone (10 microM) alone or in combination with oligomycin (8 microg/ml) similarly increased the latency to AP generation. CCCP and oligomycin or rotenone and oligomycin treatment caused rhodamine 123 loss from mitochondria within a few minutes, confirming that the mitochondrial membrane potential was dissipated during drug exposure. Oligomycin alone had no effect on the latency to AP generation and did not cause loss of rhodamine 123 from mitochondria. The increase in latency induced by CCCP and oligomycin was similar when recordings were made with either the perforated patch or standard whole cell patch recording configuration. Exposure to the endoplasmic reticulum Ca-ATPase inhibitor thapsigargin (1 microM), decreased the latency to AP generation. In cells pretreated with thapsigargin to eliminate CICR, CCCP and oligomycin had no effect on AP latency. Pretreatment with iberiotoxin (IBX; 100 nM), an inhibitor of large conductance, calcium- and voltage-activated potassium channels, reduced the extent of the CCCP- and oligomycin-induced increase in latency to AP generation. These results indicate that treatment with CCCP or rotenone to dissipate the mitochondrial membrane potential, a condition which should minimize sequestration of Ca2+ by mitochondria, facilitated the Ca(2+)-induced Ca2+ release activation of IBX-sensitive and IBX-insensitive conductances that regulate AP generation.
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Affiliation(s)
- K L Barstow
- Department of Anatomy and Neurobiology, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, USA
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