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Bian X, Zhu J, Jia X, Liang W, Yu S, Li Z, Zhang W, Rao Y. Suggestion of creatine as a new neurotransmitter by approaches ranging from chemical analysis and biochemistry to electrophysiology. eLife 2023; 12:RP89317. [PMID: 38126335 PMCID: PMC10735228 DOI: 10.7554/elife.89317] [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] [Indexed: 12/23/2023] Open
Abstract
The discovery of a new neurotransmitter, especially one in the central nervous system, is both important and difficult. We have been searching for new neurotransmitters for 12 y. We detected creatine (Cr) in synaptic vesicles (SVs) at a level lower than glutamate and gamma-aminobutyric acid but higher than acetylcholine and 5-hydroxytryptamine. SV Cr was reduced in mice lacking either arginine:glycine amidinotransferase (a Cr synthetase) or SLC6A8, a Cr transporter with mutations among the most common causes of intellectual disability in men. Calcium-dependent release of Cr was detected after stimulation in brain slices. Cr release was reduced in Slc6a8 and Agat mutants. Cr inhibited neocortical pyramidal neurons. SLC6A8 was necessary for Cr uptake into synaptosomes. Cr was found by us to be taken up into SVs in an ATP-dependent manner. Our biochemical, chemical, genetic, and electrophysiological results are consistent with the possibility of Cr as a neurotransmitter, though not yet reaching the level of proof for the now classic transmitters. Our novel approach to discover neurotransmitters is to begin with analysis of contents in SVs before defining their function and physiology.
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Affiliation(s)
- Xiling Bian
- Laboratory of Neurochemical Biology, PKU-IDG/McGovern Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking UniversityBeijingChina
- Chinese Institute for Brain Research (CIBR)BeijingChina
| | - Jiemin Zhu
- Laboratory of Neurochemical Biology, PKU-IDG/McGovern Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking UniversityBeijingChina
- Chinese Institute for Brain Research (CIBR)BeijingChina
| | - Xiaobo Jia
- Laboratory of Neurochemical Biology, PKU-IDG/McGovern Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking UniversityBeijingChina
- Chinese Institute for Brain Research (CIBR)BeijingChina
| | - Wenjun Liang
- Chinese Institutes of Medical Research, Capital Medical UniversityBeijingChina
- Changping Laboratory, Yard 28, Science Park Road, Changping DistrictBeijingChina
| | - Sihan Yu
- Laboratory of Neurochemical Biology, PKU-IDG/McGovern Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking UniversityBeijingChina
- Changping Laboratory, Yard 28, Science Park Road, Changping DistrictBeijingChina
| | - Zhiqiang Li
- Laboratory of Neurochemical Biology, PKU-IDG/McGovern Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking UniversityBeijingChina
| | - Wenxia Zhang
- Laboratory of Neurochemical Biology, PKU-IDG/McGovern Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking UniversityBeijingChina
- Chinese Institutes of Medical Research, Capital Medical UniversityBeijingChina
- Institute of Molecular Physiology, Shenzhen Bay LaboratoryShenzhenChina
| | - Yi Rao
- Laboratory of Neurochemical Biology, PKU-IDG/McGovern Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking UniversityBeijingChina
- Chinese Institute for Brain Research (CIBR)BeijingChina
- Chinese Institutes of Medical Research, Capital Medical UniversityBeijingChina
- Changping Laboratory, Yard 28, Science Park Road, Changping DistrictBeijingChina
- Institute of Molecular Physiology, Shenzhen Bay LaboratoryShenzhenChina
- Research Unit of Medical Neurobiology, Chinese Academy of Medical SciencesBeijingChina
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Furukawa T, Fukuda A. Maternal taurine as a modulator of Cl - homeostasis as well as of glycine/GABA A receptors for neocortical development. Front Cell Neurosci 2023; 17:1221441. [PMID: 37601283 PMCID: PMC10435090 DOI: 10.3389/fncel.2023.1221441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/20/2023] [Indexed: 08/22/2023] Open
Abstract
During brain and spinal cord development, GABA and glycine, the inhibitory neurotransmitters, cause depolarization instead of hyperpolarization in adults. Since glycine and GABAA receptors (GABAARs) are chloride (Cl-) ion channel receptor, the conversion of GABA/glycine actions during development is influenced by changes in the transmembrane Cl- gradient, which is regulated by Cl- transporters, NKCC1 (absorption) and KCC2 (expulsion). In immature neurons, inhibitory neurotransmitters are released in a non-vesicular/non-synaptic manner, transitioning to vesicular/synaptic release as the neuron matures. In other word, in immature neurons, neurotransmitters generally act tonically. Thus, the glycine/GABA system is a developmentally multimodal system that is required for neurogenesis, differentiation, migration, and synaptogenesis. The endogenous agonists for these receptors are not fully understood, we address taurine. In this review, we will discuss about the properties and function of taurine during development of neocortex. Taurine cannot be synthesized by fetuses or neonates, and is transferred from maternal blood through the placenta or maternal milk ingestion. In developing neocortex, taurine level is higher than GABA level, and taurine tonically activates GABAARs to control radial migration as a stop signal. In the marginal zone (MZ) of the developing neocortex, endogenous taurine modulates the spread of excitatory synaptic transmission, activating glycine receptors (GlyRs) as an endogenous agonist. Thus, taurine affects information processing and crucial developmental processes such as axonal growth, cell migration, and lamination in the developing cerebral cortex. Additionally, we also refer to the possible mechanism of taurine-regulating Cl- homeostasis. External taurine is uptake by taurine transporter (TauT) and regulates NKCC1 and KCC2 mediated by intracellular signaling pathway, with-no-lysine kinase 1 (WNK1) and its subsequent kinases STE20/SPS1-related proline-alanine-rich protein kinase (SPAK) and oxidative stress response kinase-1 (OSR1). Through the regulation of NKCC1 and KCC2, mediated by the WNK-SPAK/OSR1 signaling pathway, taurine plays a role in maintaining Cl- homeostasis during normal brain development.
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Affiliation(s)
- Tomonori Furukawa
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Furukawa T, Yamada J, Akita T, Matsushima Y, Yanagawa Y, Fukuda A. Roles of taurine-mediated tonic GABAA receptor activation in the radial migration of neurons in the fetal mouse cerebral cortex. Front Cell Neurosci 2014; 8:88. [PMID: 24734001 PMCID: PMC3975117 DOI: 10.3389/fncel.2014.00088] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 03/10/2014] [Indexed: 11/15/2022] Open
Abstract
γ-Aminobutyric acid (GABA) depolarizes embryonic cerebrocortical neurons and continuous activation of the GABAA receptor (GABAAR) contributes to their tonic depolarization. Although multiple reports have demonstrated a role of GABAAR activation in neocortical development, including in migration, most of these studies have used pharmacological blockers. Herein, we performed in utero electroporation in GABA synthesis-lacking homozygous GAD67-GFP knock-in mice (GAD67GFP/GFP) to label neurons born in the ventricular zone. Three days after electroporation, there were no differences in the distribution of labeled cells between the genotypes. The dose–response properties of labeled cells to GABA were equivalent among genotypes. However, continuous blockade of GABAAR with the GABAAR antagonist SR95531 accelerated radial migration. This effect of GABAAR blockade in GAD67GFP/GFP mice suggested a role for alternative endogenous GABAAR agonists. Thus, we tested the role of taurine, which is derived from maternal blood but is abundant in the fetal brain. The taurine-evoked currents in labeled cells were mediated by GABAAR. Taurine uptake was blocked by a taurine transporter inhibitor, 2-(guanidino)ethanesulfonic acid (GES), and taurine release was blocked by a volume-sensitive anion channel blocker, 4-(2-butyl-6,7-dichlor-2-cyclopentylindan-1-on-5-yl) oxobutyric acid, as examined through high-performance liquid chromatography. GES increased the extracellular taurine concentration and induced an inward shift of the holding current, which was reversed by SR95531. In a taurine-deficient mouse model, the GABAAR-mediated tonic currents were greatly reduced, and radial migration was accelerated. As the tonic currents were equivalent among the genotypes of GAD67-GFP knock-in mice, taurine, rather than GABA, might play a major role as an endogenous agonist of embryonic tonic GABAAR conductance, regulating the radial migration of neurons in the developing neocortex.
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Affiliation(s)
- Tomonori Furukawa
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
| | - Junko Yamada
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan ; Department of Neurophysiology, Hirosaki University Graduate School of Medicine Hirosaki, Aomori, Japan
| | - Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
| | - Yoshitaka Matsushima
- Department of Chemistry, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine Maebashi, Gunma, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
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Molchanova SM, Oja SS, Saransaari P. Properties of basal taurine release in the rat striatum in vivo. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006; 583:365-75. [PMID: 17153622 DOI: 10.1007/978-0-387-33504-9_41] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Svetlana M Molchanova
- Medical School, Brain Research Center, FI-33014 University of Tampere, Finland. svetlana.molchanova@-u.ac.jp
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Molchanova SM, Oja SS, Saransaari P. Mechanisms of enhanced taurine release under Ca2+ depletion. Neurochem Int 2005; 47:343-9. [PMID: 15982785 DOI: 10.1016/j.neuint.2005.04.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2004] [Revised: 04/22/2005] [Accepted: 04/22/2005] [Indexed: 11/19/2022]
Abstract
The sulfur-containing amino acid taurine is an inhibitory neuromodulator in the brain of mammals, as well as a key substance in the regulation of cell volumes. The effect of Ca(2+) on extracellular taurine concentrations is of special interest in the context of the regulatory mechanisms of taurine release. The aim of this study was to characterize the basal release of taurine in Ca(2+)-free medium using in vivo microdialysis of the striatum of anesthetized rats. Perfusion of Ca(2+)-free medium via a microdialysis probe evoked a sustained release of taurine (up to 180 % compared to the basal levels). The Ca(2+) chelator EGTA (1mM) potentiated Ca(2+) depletion-evoked taurine release. The substitution of CaCl(2) by choline chloride did not alter the observed effect. Ca(2+)-free solution did not significantly evoke release of taurine from tissue loaded with the competitive inhibitor of taurine transporter guanidinoethanesulfonate (1mM), suggesting that in Ca(2+) depletion taurine is released by the transporter operating in the outward direction. The volume-sensitive chloride channel blocker diisothiocyanostilbene-2,2'-disulfonate (1mM) did not attenuate the taurine release evoked by Ca(2+) depletion. The non-specific blocker of voltage-sensitive Ca(2+) channels NiCl(2) (0.65 mM) enhanced taurine release in the presence of Ca(2+). CdCl(2) (0.25 mM) had no effect under these conditions. However, both CdCl(2) and NiCl(2) attenuated the effect of Ca(2+)-free medium on the release of taurine. The data obtained imply the involvement of both decreased influx of Ca(2+) and increased non-specific influx of Na(+) through voltage-sensitive calcium channels in the regulation of transporter-mediated taurine release in Ca(2+) depletion.
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Enomoto R, Tatsuoka H, Komai T, Sugahara C, Takemura K, Yamauchi A, Nishimura M, Naito S, Matsuda T, Lee E. Involvement of histone phosphorylation in apoptosis of human astrocytes after exposure to saline solution. Neurochem Int 2004; 44:459-67. [PMID: 14687611 DOI: 10.1016/s0197-0186(03)00175-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have previously found using inhibitors of protein phosphatase that phosphorylation of histones may be involved in thymocyte apoptosis. In this study, we examined whether histone modification occurs in astrocyte apoptosis induced by a pathological condition in the absence of drug. Incubation of cultured human astrocytes with growth medium for 24 h after exposure to saline solution for 30 min induced an increase in terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells and nuclear condensation, biochemical and morphological hallmarks of apoptotic cell death. Acetic acid-urea-Triton X-100 (AUT) gel electrophoresis of the nuclear histone fraction and N-terminal peptide analysis showed that the treatment with saline solution caused rapid changes in phosphorylation of H2A subfamilies, but not in histone acetylation. The phosphorylation of the two subtypes increased markedly, whereas the phosphorylation of one subtype decreased. In contrast, exposure to ACF-95, an artificial cerebrospinal fluid (CSF), was associated with little induction of apoptotic cell death and induced less changes in histone phosphorylation. These results support the previous idea that chemical modification of histones is involved in the DNA fragmentation in astrocytes undergoing apoptosis.
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Affiliation(s)
- Riyo Enomoto
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Ikawadani-cho, Nishi-ku, Kobe 651-2180, Japan
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Deleuze C, Duvoid A, Hussy N. Properties and glial origin of osmotic-dependent release of taurine from the rat supraoptic nucleus. J Physiol 1998; 507 ( Pt 2):463-71. [PMID: 9518705 PMCID: PMC2230788 DOI: 10.1111/j.1469-7793.1998.463bt.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
1. Taurine, prominently concentrated in glial cells in the supraoptic nucleus (SON), is probably involved in the inhibition of SON vasopressin neurones by peripheral hypotonic stimulus, via activation of neuronal glycine receptors. We report here the properties and origin of the osmolarity-dependent release of preloaded [3H]taurine from isolated whole SO nuclei. 2. Hyposmotic medium induced a rapid, reversible and dose-dependent increase in taurine release. Release showed a high sensitivity to osmotic change, with a significant enhancement with less than a 5% decrease in osmolarity. Hyperosmotic stimulus decreased basal release. 3. Evoked release was independent of extracellular Ca2+ and Na+, and was blocked by the Cl- channel blockers DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid) and DPC (N-phenylanthranilic acid), suggesting a diffusion process through volume-sensitive Cl- channels. 4. Evoked release was transient for large osmotic reductions (> or = 15%), probably reflecting regulatory volume decrease (RVD). However, it was sustained for smaller changes, suggesting that taurine release induced by physiological variations in osmolarity is not linked to RVD. 5. Basal and evoked release were strongly inhibited by an incubation of the tissue with the glia-specific toxin fluorocitrate, but were unaffected by a neurotoxic-treatment with NMDA, demonstrating the glial origin of the release of taurine in the SON. 6. The high osmosensitivity of taurine release suggests an important role in the osmoregulation of the SON function. These results strengthen the notion of an implication of taurine and glial cells in the regulation of the whole-body fluid balance through the modulation of vasopressin release.
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Affiliation(s)
- C Deleuze
- Biologie des Neurones Endocrines, CNRS-UPR 9055, Montpellier, France
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