1
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Li JM, Bai YZ, Zhang SQ. Advances and challenges in serine in the central nervous system: physicochemistry, physiology, and pharmacology. Metab Brain Dis 2024:10.1007/s11011-024-01418-4. [PMID: 39186223 DOI: 10.1007/s11011-024-01418-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Accepted: 08/18/2024] [Indexed: 08/27/2024]
Abstract
Neurological disorders are the primary cause of human disability and mortality globally, however, current medications slightly alleviate some symptoms of degenerative diseases. Serine is an important amino acid for the brain function and involved in a variety of biosynthetic pathways and signal transduction processes. The imbalance of serine metabolism is associated with neurodegeneration, including neuroinflammation, oxidative stress and apoptosis. Altered activities of serine metabolizing enzymes and accumulation of serine metabolites affect the survival and function of nerve cells. Abnormal serine levels are observed in animal models with neurological diseases, but not all human studies, therefore, the maintenance of serine homeostasis is a potentially therapeutic strategy for neurological disorders. To date, physiological and pharmacological roles of serine in neurological diseases have not been systemically recapitulated, and the association between serine and neurological diseases is controversial. In this review, we summarize physicochemical properties of serine, biological processes of serine in the brain (source, biotransformation, and transport), and the application of serine in neurological diseases including Alzheimer's disease, schizophrenia, and depression. Here, we highlight physicochemistry, physiology, pharmacology, and therapeutic potentials of serine in the prevention and treatment of neurological dysfunction. Our work provides valuable hints for future investigation that will lead to a comprehensive understanding of serine and its metabolism in cellular physiology and pharmacology. Although broad by necessity, the review helps researchers to understand great potentials of serine in the prevention and treatment of neurological dysfunction.
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Affiliation(s)
- Jia-Meng Li
- National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, 27 Nanwei Road, Beijing, 100050, China
| | - Ya-Zhi Bai
- National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, 27 Nanwei Road, Beijing, 100050, China
| | - Shuang-Qing Zhang
- National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, 27 Nanwei Road, Beijing, 100050, China.
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2
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Kim H, Choi S, Lee E, Koh W, Lee CJ. Tonic NMDA Receptor Currents in the Brain: Regulation and Cognitive Functions. Biol Psychiatry 2024; 96:164-175. [PMID: 38490367 DOI: 10.1016/j.biopsych.2024.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 02/20/2024] [Accepted: 03/04/2024] [Indexed: 03/17/2024]
Abstract
Synaptically localized NMDA receptors (NMDARs) play a crucial role in important cognitive functions by mediating synaptic transmission and plasticity. In contrast, a tonic NMDAR current, thought to be mediated by extrasynaptic NMDARs, has a less clear function. This review provides a comprehensive overview of tonic NMDAR currents, focusing on their roles in synaptic transmission/plasticity and their impact on cognitive functions and psychiatric disorders. We discuss the roles of 3 endogenous ligands (i.e., glutamate, glycine, and D-serine) and receptors in mediating tonic NMDAR currents and explore the diverse mechanisms that regulate tonic NMDAR currents. In light of recent controversies surrounding the source of D-serine, we highlight the recent findings suggesting that astrocytes release D-serine to modulate tonic NMDAR currents and control cognitive flexibility. Furthermore, we propose distinct roles of neuronal and astrocytic D-serine in different locations and their implications for synaptic regulation and cognitive functions. The potential roles of tonic NMDAR currents in various psychiatric disorders, such as schizophrenia and autism spectrum disorder, are discussed in the context of the NMDAR hypofunction hypothesis. By presenting the mechanisms by which various cells, particularly astrocytes, regulate tonic NMDAR currents, we aim to stimulate future research in NMDAR hypofunction- or hyperfunction-related psychiatric disorders. This review not only provides a better understanding of the complex interplay between tonic NMDAR currents and cognitive functions but also sheds light on its potential therapeutic target for the treatment of various psychiatric disorders.
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Affiliation(s)
- Hayoung Kim
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science, Daejeon, South Korea
| | - Sunyeong Choi
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science, Daejeon, South Korea
| | - Euisun Lee
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science, Daejeon, South Korea
| | - Wuhyun Koh
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science, Daejeon, South Korea.
| | - C Justin Lee
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science, Daejeon, South Korea.
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3
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Biswas DD, Shi Y, El Haddad L, Sethi R, Huston M, Kehoe S, Scarrow ER, Strickland LM, Pucci LA, Dhindsa JS, Hunanyan A, La Spada AR, ElMallah MK. Respiratory neuropathology in spinocerebellar ataxia type 7. JCI Insight 2024; 9:e170444. [PMID: 39053472 PMCID: PMC11457860 DOI: 10.1172/jci.insight.170444] [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: 03/20/2023] [Accepted: 07/12/2024] [Indexed: 07/27/2024] Open
Abstract
Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant neurological disorder caused by deleterious CAG repeat expansion in the coding region of the ataxin 7 gene (polyQ-ataxin-7). Infantile-onset SCA7 leads to severe clinical manifestation of respiratory distress, but the exact cause of respiratory impairment remains unclear. Using the infantile-SCA7 mouse model, the SCA7266Q/5Q mouse, we examined the impact of pathological polyQ-ataxin-7 on hypoglossal (XII) and phrenic motor units. We identified the transcript profile of the medulla and cervical spinal cord and investigated the XII and phrenic nerves and the neuromuscular junctions in the diaphragm and tongue. SCA7266Q/5Q astrocytes showed significant intranuclear inclusions of ataxin-7 in the XII and putative phrenic motor nuclei. Transcriptomic analysis revealed dysregulation of genes involved in amino acid and neurotransmitter transport and myelination. Additionally, SCA7266Q/5Q mice demonstrated blunted efferent output of the XII nerve and demyelination in both XII and phrenic nerves. Finally, there was an increased number of neuromuscular junction clusters with higher expression of synaptic markers in SCA7266Q/5Q mice compared with WT controls. These preclinical findings elucidate the underlying pathophysiology responsible for impaired glial cell function and death leading to dysphagia, aspiration, and respiratory failure in infantile SCA7.
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Affiliation(s)
- Debolina D Biswas
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Yihan Shi
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Léa El Haddad
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Ronit Sethi
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Meredith Huston
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Sean Kehoe
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Evelyn R Scarrow
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Laura M Strickland
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Logan A Pucci
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Justin S Dhindsa
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Ani Hunanyan
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Albert R La Spada
- Departments of Pathology and Laboratory Medicine, Neurology, Biological Chemistry, and Neurobiology and Behavior, and
- UCI Center for Neurotherapeutics, University of California Irvine, Irvine, California, USA
| | - Mai K ElMallah
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
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4
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Schaefer N, Harvey RJ, Villmann C. Startle Disease: New Molecular Insights into an Old Neurological Disorder. Neuroscientist 2023; 29:767-781. [PMID: 35754344 PMCID: PMC10623600 DOI: 10.1177/10738584221104724] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Startle disease (SD) is characterized by enhanced startle responses, generalized muscle stiffness, unexpected falling, and fatal apnea episodes due to disturbed feedback inhibition in the spinal cord and brainstem of affected individuals. Mutations within the glycine receptor (GlyR) subunit and glycine transporter 2 (GlyT2) genes have been identified in individuals with SD. Impaired inhibitory neurotransmission in SD is due to pre- and/or postsynaptic GlyR or presynaptic GlyT2 dysfunctions. Previous research has focused on mutated GlyRs and GlyT2 that impair ion channel/transporter function or trafficking. With insights provided by recently solved cryo-electron microscopy and X-ray structures of GlyRs, a detailed picture of structural transitions important for receptor gating has emerged, allowing a deeper understanding of SD at the molecular level. Moreover, studies on novel SD mutations have demonstrated a higher complexity of SD, with identification of additional clinical signs and symptoms and interaction partners representing key players for fine-tuning synaptic processes. Although our knowledge has steadily improved during the last years, changes in synaptic localization and GlyR or GlyT2 homeostasis under disease conditions are not yet completely understood. Combined proteomics, interactomics, and high-resolution microscopy techniques are required to reveal alterations in receptor dynamics at the synaptic level under disease conditions.
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Affiliation(s)
- Natascha Schaefer
- Institute of Clinical Neurobiology, University Hospital, Julius-Maximilians-University of Würzburg, Würzburg, Germany
| | - Robert J. Harvey
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Maroochydore DC, Australia
- Sunshine Coast Health Institute, Birtinya, Australia
| | - Carmen Villmann
- Institute of Clinical Neurobiology, University Hospital, Julius-Maximilians-University of Würzburg, Würzburg, Germany
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Drehmann P, Milanos S, Schaefer N, Kasaragod VB, Herterich S, Holzbach-Eberle U, Harvey RJ, Villmann C. Dual Role of Dysfunctional Asc-1 Transporter in Distinct Human Pathologies, Human Startle Disease, and Developmental Delay. eNeuro 2023; 10:ENEURO.0263-23.2023. [PMID: 37903619 PMCID: PMC10668224 DOI: 10.1523/eneuro.0263-23.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 09/11/2023] [Indexed: 11/01/2023] Open
Abstract
Human startle disease is associated with mutations in distinct genes encoding glycine receptors, transporters or interacting proteins at glycinergic synapses in spinal cord and brainstem. However, a significant number of diagnosed patients does not carry a mutation in the common genes GLRA1, GLRB, and SLC6A5 Recently, studies on solute carrier 7 subfamily 10 (SLC7A10; Asc-1, alanine-serine-cysteine transporter) knock-out (KO) mice displaying a startle disease-like phenotype hypothesized that this transporter might represent a novel candidate for human startle disease. Here, we screened 51 patients from our patient cohort negative for the common genes and found three exonic (one missense, two synonymous), seven intronic, and single nucleotide changes in the 5' and 3' untranslated regions (UTRs) in Asc-1. The identified missense mutation Asc-1G307R from a patient with startle disease and developmental delay was investigated in functional studies. At the molecular level, the mutation Asc-1G307R did not interfere with cell-surface expression, but disrupted glycine uptake. Substitution of glycine at position 307 to other amino acids, e.g., to alanine or tryptophan did not affect trafficking or glycine transport. By contrast, G307K disrupted glycine transport similar to the G307R mutation found in the patient. Structurally, the disrupted function in variants carrying positively charged residues can be explained by local structural rearrangements because of the large positively charged side chain. Thus, our data suggest that SLC7A10 may represent a rare but novel gene associated with human startle disease and developmental delay.
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Affiliation(s)
- Paul Drehmann
- Institute for Clinical Neurobiology, Julius Maximilians University of Würzburg, 97078 Würzburg, Germany
| | - Sinem Milanos
- Institute for Clinical Neurobiology, Julius Maximilians University of Würzburg, 97078 Würzburg, Germany
| | - Natascha Schaefer
- Institute for Clinical Neurobiology, Julius Maximilians University of Würzburg, 97078 Würzburg, Germany
| | - Vikram Babu Kasaragod
- Neurobiology Division, Medical Reserach Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Sarah Herterich
- Institute for Clinical Neurobiology, Julius Maximilians University of Würzburg, 97078 Würzburg, Germany
| | - Ulrike Holzbach-Eberle
- Center for Pediatrics and Adolescent Medicine, Pediatric Neurology, Social Pediatrics and Epileptology, University Hospital Gießen, 35392 Giessen, Germany
| | - Robert J Harvey
- School of Health, University of the Sunshine Coast, Sippy Downs, QLD 4558, Australia
- Sunshine Coast Health Institute, Birtinya, QLD 4575, Australia
| | - Carmen Villmann
- Institute for Clinical Neurobiology, Julius Maximilians University of Würzburg, 97078 Würzburg, Germany
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6
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Fogarty MJ. Inhibitory Synaptic Influences on Developmental Motor Disorders. Int J Mol Sci 2023; 24:ijms24086962. [PMID: 37108127 PMCID: PMC10138861 DOI: 10.3390/ijms24086962] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/05/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
During development, GABA and glycine play major trophic and synaptic roles in the establishment of the neuromotor system. In this review, we summarise the formation, function and maturation of GABAergic and glycinergic synapses within neuromotor circuits during development. We take special care to discuss the differences in limb and respiratory neuromotor control. We then investigate the influences that GABAergic and glycinergic neurotransmission has on two major developmental neuromotor disorders: Rett syndrome and spastic cerebral palsy. We present these two syndromes in order to contrast the approaches to disease mechanism and therapy. While both conditions have motor dysfunctions at their core, one condition Rett syndrome, despite having myriad symptoms, has scientists focused on the breathing abnormalities and their alleviation-to great clinical advances. By contrast, cerebral palsy remains a scientific quagmire or poor definitions, no widely adopted model and a lack of therapeutic focus. We conclude that the sheer abundance of diversity of inhibitory neurotransmitter targets should provide hope for intractable conditions, particularly those that exhibit broad spectra of dysfunction-such as spastic cerebral palsy and Rett syndrome.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55902, USA
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7
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Tacke C, Bischoff AM, Harb A, Vafadari B, Hülsmann S. Angiotensin II increases respiratory rhythmic activity in the preBötzinger complex without inducing astroglial calcium signaling. Front Cell Neurosci 2023; 17:1111263. [PMID: 36816850 PMCID: PMC9932970 DOI: 10.3389/fncel.2023.1111263] [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: 11/29/2022] [Accepted: 01/17/2023] [Indexed: 02/05/2023] Open
Abstract
Angiotensin II (Ang II) is the primary modulator of the renin-angiotensin system and has been widely studied for its effect on the cardiovascular system. While a few studies have also indicated an involvement of Ang II in the regulation of breathing, very little is known in this regard and its effect on brainstem respiratory regions such as the preBötzinger complex (preBötC), the kernel for inspiratory rhythm generation, has not been investigated yet. This study reports that Ang II temporarily increases phrenic nerve activity in the working heart-brainstem preparation, indicating higher central respiratory drive. Previous studies have shown that the carotid body is involved in mediating this effect and we revealed that the preBötC also plays a part, using acute slices of the brainstem. It appears that Ang II is increasing the respiratory drive in an AT1R-dependent manner by optimizing the interaction of inhibitory and excitatory neurons of the preBötC. Thus, Ang II-mediated effects on the preBötC are potentially involved in dysregulating breathing in patients with acute lung injury.
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8
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Jersin RÅ, Jonassen LR, Dankel SN. The neutral amino acid transporter SLC7A10 in adipose tissue, obesity and insulin resistance. Front Cell Dev Biol 2022; 10:974338. [PMID: 36172277 PMCID: PMC9512047 DOI: 10.3389/fcell.2022.974338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 08/26/2022] [Indexed: 12/02/2022] Open
Abstract
Obesity, insulin resistance and type 2 diabetes represent major global health challenges, and a better mechanistic understanding of the altered metabolism in these conditions may give improved treatment strategies. SLC7A10, a member of the SLC7 subfamily of solute carriers, also named ASC-1 (alanine, serine, cysteine transporter-1), has recently been implicated as an important modulator of core processes in energy- and lipid metabolism, through its particularly high expression in adipocytes. In human cohorts, adipose SLC7A10 mRNA shows strong inverse correlations with insulin resistance, adipocyte size and components of the metabolic syndrome, strong heritability, and an association with type 2 diabetes risk alleles. SLC7A10 has been proposed as a marker of white as opposed to thermogenic beige and brown adipocytes, supported by increased formation of thermogenic beige adipocytes upon loss of Slc7a10 in mouse white preadipocytes. Overexpression of SLC7A10 in mature white adipocytes was found to lower the generation of reactive oxygen species (ROS) and stimulate mitochondrial respiratory capacity, while SLC7A10 inhibition had the opposite effect, indicating that SLC7A10 supports a beneficial increase in mitochondrial activity in white adipocytes. Consistent with these beneficial effects, inhibition of SLC7A10 was in mouse and human white adipocyte cultures found to increase lipid accumulation, likely explained by lowered serine uptake and glutathione production. Additionally, zebrafish with partial global Slc7a10b loss-of-function were found to have greater diet-induced body weight and larger visceral adipocytes compared to controls. However, challenging that SLC7A10 exerts metabolic benefits only in white adipocytes, suppression of SLC7A10 has been reported to decrease mitochondrial respiration and expression of thermogenic genes also in some beige and brown adipocyte cultures. Taken together, the data point to an important but complex role of SLC7A10 in metabolic regulation across different adipose tissue depots and adipocyte subtypes. Further research into SLC7A10 functions in specific adipocyte subtypes may lead to new precision therapeutics for mitigating the risk of insulin resistance and type 2 diabetes.
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Affiliation(s)
- Regine Åsen Jersin
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Laura Roxana Jonassen
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Simon Nitter Dankel
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway
- *Correspondence: Simon Nitter Dankel,
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9
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Eulenburg V, Hülsmann S. Synergistic Control of Transmitter Turnover at Glycinergic Synapses by GlyT1, GlyT2, and ASC-1. Int J Mol Sci 2022; 23:ijms23052561. [PMID: 35269698 PMCID: PMC8909939 DOI: 10.3390/ijms23052561] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 01/25/2023] Open
Abstract
In addition to being involved in protein biosynthesis and metabolism, the amino acid glycine is the most important inhibitory neurotransmitter in caudal regions of the brain. These functions require a tight regulation of glycine concentration not only in the synaptic cleft, but also in various intracellular and extracellular compartments. This is achieved not only by confining the synthesis and degradation of glycine predominantly to the mitochondria, but also by the action of high-affinity large-capacity glycine transporters that mediate the transport of glycine across the membranes of presynaptic terminals or glial cells surrounding the synapses. Although most cells at glycine-dependent synapses express more than one transporter with high affinity for glycine, their synergistic functional interaction is only poorly understood. In this review, we summarize our current knowledge of the two high-affinity transporters for glycine, the sodium-dependent glycine transporters 1 (GlyT1; SLC6A9) and 2 (GlyT2; SLC6A5) and the alanine–serine–cysteine-1 transporter (Asc-1; SLC7A10).
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Affiliation(s)
- Volker Eulenburg
- Department for Anesthesiology and Intensive Care, Faculty of Medicine, University of Leipzig, Liebigstraße 20, D-04103 Leipzig, Germany
- Correspondence: (V.E.); (S.H.)
| | - Swen Hülsmann
- Department for Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany
- Correspondence: (V.E.); (S.H.)
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10
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Tatsumi K, Kinugawa K, Isonishi A, Kitabatake M, Okuda H, Takemura S, Tanaka T, Mori E, Wanaka A. Olig2-astrocytes express neutral amino acid transporter SLC7A10 (Asc-1) in the adult brain. Mol Brain 2021; 14:163. [PMID: 34749773 PMCID: PMC8573876 DOI: 10.1186/s13041-021-00874-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 10/28/2021] [Indexed: 11/23/2022] Open
Abstract
We have reported that the transcription factor Olig2 labels a subpopulation of astrocytes (Olig2-astrocytes), which show distribution patterns different from those of GFAP-expressing astrocytes (GFAP-astrocytes) in the adult brain. Here, to uncover the specific functions of Olig2-astrocytes, we first analyzed public single-cell RNA-seq databases of adult mouse brains. Unbiased classification of gene expression profiles and subsequent gene ontology analyses revealed that the majority of Olig2-astrocytes belonged to an astrocytic cluster that is enriched for transporter-related genes. SLC7A10 (also known as ASC-1) was one of the representative neutral amino acid transporter genes in the cluster. To complement the in silico data analyses, we differentially isolated Olig2- and GFAP-astrocytes from the same frozen section of the lateral globus pallidus using laser microdissection and compared their gene expression by quantitative reverse transcription PCR. We confirmed that Olig2 and GFAP mRNAs were preferentially expressed in the Olig2- and GFAP-astrocytes, respectively, indicating that the laser microdissection method yielded minimal cross-contamination between two types of cells. The Olig2-astrocytes expressed significantly higher levels of SLC7A10 mRNA than the GFAP-astrocytes, corroborating the in silico data. We next localized SLC7A10 protein by immunohistochemistry in the lateral globus pallidus, which was also genetically labeled for Olig2. SLC7A10 co-localized with Olig2-genetic labeling, especially on the fine processes of Olig2-astrocytes. These results are consistent with the recent discovery that SLC7A10 is expressed not only in neurons but also in a subset of astrocytes. Taken together, our findings suggest that SLC7A10 exerts specific functions in Olig2-astrocytes of the adult brain.
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Affiliation(s)
- Kouko Tatsumi
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University, Kashihara, Nara, 634-8521, Japan.
| | - Kaoru Kinugawa
- Department of Neurology, Faculty of Medicine, Nara Medical University, Kashihara, Nara, 634-8521, Japan
| | - Ayami Isonishi
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University, Kashihara, Nara, 634-8521, Japan
| | - Masahiro Kitabatake
- Department of Immunology, Faculty of Medicine, Nara Medical University, Kashihara, Nara, 634-8521, Japan
| | - Hiroaki Okuda
- Department of Anatomy, Graduate School of Medical Science, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan
| | - Shoko Takemura
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University, Kashihara, Nara, 634-8521, Japan
| | - Tatsuhide Tanaka
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University, Kashihara, Nara, 634-8521, Japan
| | - Eiichiro Mori
- Department of Future Basic Medicine, Faculty of Medicine, Nara Medical University, Kashihara, Nara, 634-8521, Japan
| | - Akio Wanaka
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University, Kashihara, Nara, 634-8521, Japan
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11
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Yair S, Lee KM, Coop G. The timing of human adaptation from Neanderthal introgression. Genetics 2021; 218:iyab052. [PMID: 33787889 PMCID: PMC8128397 DOI: 10.1093/genetics/iyab052] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 02/26/2021] [Indexed: 12/26/2022] Open
Abstract
Admixture has the potential to facilitate adaptation by providing alleles that are immediately adaptive in a new environment or by simply increasing the long-term reservoir of genetic diversity for future adaptation. A growing number of cases of adaptive introgression are being identified in species across the tree of life, however the timing of selection, and therefore the importance of the different evolutionary roles of admixture, is typically unknown. Here, we investigate the spatio-temporal history of selection favoring Neanderthal-introgressed alleles in modern human populations. Using both ancient and present-day samples of modern humans, we integrate the known demographic history of populations, namely population divergence and migration, with tests for selection. We model how a sweep placed along different branches of an admixture graph acts to modify the variance and covariance in neutral allele frequencies among populations at linked loci. Using a method based on this model of allele frequencies, we study previously identified cases of adaptive Neanderthal introgression. From these, we identify cases in which Neanderthal-introgressed alleles were quickly beneficial and other cases in which they persisted at low frequency for some time. For some of the alleles that persisted at low frequency, we show that selection likely independently favored them later on in geographically separated populations. Our work highlights how admixture with ancient hominins has contributed to modern human adaptation and contextualizes observed levels of Neanderthal ancestry in present-day and ancient samples.
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Affiliation(s)
- Sivan Yair
- Center for Population Biology, University of California, Davis, Davis, CA 95616, USA
- Department of Evolution and Ecology, University of California, Davis, Davis, CA 95616, USA
| | - Kristin M Lee
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Graham Coop
- Center for Population Biology, University of California, Davis, Davis, CA 95616, USA
- Department of Evolution and Ecology, University of California, Davis, Davis, CA 95616, USA
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12
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Fairweather SJ, Shah N, Brӧer S. Heteromeric Solute Carriers: Function, Structure, Pathology and Pharmacology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 21:13-127. [PMID: 33052588 DOI: 10.1007/5584_2020_584] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Solute carriers form one of three major superfamilies of membrane transporters in humans, and include uniporters, exchangers and symporters. Following several decades of molecular characterisation, multiple solute carriers that form obligatory heteromers with unrelated subunits are emerging as a distinctive principle of membrane transporter assembly. Here we comprehensively review experimentally established heteromeric solute carriers: SLC3-SLC7 amino acid exchangers, SLC16 monocarboxylate/H+ symporters and basigin/embigin, SLC4A1 (AE1) and glycophorin A exchanger, SLC51 heteromer Ost α-Ost β uniporter, and SLC6 heteromeric symporters. The review covers the history of the heteromer discovery, transporter physiology, structure, disease associations and pharmacology - all with a focus on the heteromeric assembly. The cellular locations, requirements for complex formation, and the functional role of dimerization are extensively detailed, including analysis of the first complete heteromer structures, the SLC7-SLC3 family transporters LAT1-4F2hc, b0,+AT-rBAT and the SLC6 family heteromer B0AT1-ACE2. We present a systematic analysis of the structural and functional aspects of heteromeric solute carriers and conclude with common principles of their functional roles and structural architecture.
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Affiliation(s)
- Stephen J Fairweather
- Research School of Biology, Australian National University, Canberra, ACT, Australia. .,Resarch School of Chemistry, Australian National University, Canberra, ACT, Australia.
| | - Nishank Shah
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Stefan Brӧer
- Research School of Biology, Australian National University, Canberra, ACT, Australia.
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13
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Brill SE, Maraslioglu A, Kurz C, Kramer F, Fuhr MF, Singh A, Friauf E. Glycinergic Transmission in the Presence and Absence of Functional GlyT2: Lessons From the Auditory Brainstem. Front Synaptic Neurosci 2021; 12:560008. [PMID: 33633558 PMCID: PMC7900164 DOI: 10.3389/fnsyn.2020.560008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 12/01/2020] [Indexed: 12/20/2022] Open
Abstract
Synaptic transmission is controlled by re-uptake systems that reduce transmitter concentrations in the synaptic cleft and recycle the transmitter into presynaptic terminals. The re-uptake systems are thought to ensure cytosolic concentrations in the terminals that are sufficient for reloading empty synaptic vesicles (SVs). Genetic deletion of glycine transporter 2 (GlyT2) results in severely disrupted inhibitory neurotransmission and ultimately to death. Here we investigated the role of GlyT2 at inhibitory glycinergic synapses in the mammalian auditory brainstem. These synapses are tuned for resilience, reliability, and precision, even during sustained high-frequency stimulation when endocytosis and refilling of SVs probably contribute substantially to efficient replenishment of the readily releasable pool (RRP). Such robust synapses are formed between MNTB and LSO neurons (medial nucleus of the trapezoid body, lateral superior olive). By means of patch-clamp recordings, we assessed the synaptic performance in controls, in GlyT2 knockout mice (KOs), and upon acute pharmacological GlyT2 blockade. Via computational modeling, we calculated the reoccupation rate of empty release sites and RRP replenishment kinetics during 60-s challenge and 60-s recovery periods. Control MNTB-LSO inputs maintained high fidelity neurotransmission at 50 Hz for 60 s and recovered very efficiently from synaptic depression. During 'marathon-experiments' (30,600 stimuli in 20 min), RRP replenishment accumulated to 1,260-fold. In contrast, KO inputs featured severe impairments. For example, the input number was reduced to ~1 (vs. ~4 in controls), implying massive functional degeneration of the MNTB-LSO microcircuit and a role of GlyT2 during synapse maturation. Surprisingly, neurotransmission did not collapse completely in KOs as inputs still replenished their small RRP 80-fold upon 50 Hz | 60 s challenge. However, they totally failed to do so for extended periods. Upon acute pharmacological GlyT2 inactivation, synaptic performance remained robust, in stark contrast to KOs. RRP replenishment was 865-fold in marathon-experiments, only ~1/3 lower than in controls. Collectively, our empirical and modeling results demonstrate that GlyT2 re-uptake activity is not the dominant factor in the SV recycling pathway that imparts indefatigability to MNTB-LSO synapses. We postulate that additional glycine sources, possibly the antiporter Asc-1, contribute to RRP replenishment at these high-fidelity brainstem synapses.
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Affiliation(s)
- Sina E Brill
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Ayse Maraslioglu
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Catharina Kurz
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Florian Kramer
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Martin F Fuhr
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Abhyudai Singh
- Electrical & Computer Engineering, University of Delaware, Newark, DE, United States
| | - Eckhard Friauf
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
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14
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Seckler JM, Lewis SJ. Advances in D-Amino Acids in Neurological Research. Int J Mol Sci 2020; 21:ijms21197325. [PMID: 33023061 PMCID: PMC7582301 DOI: 10.3390/ijms21197325] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/29/2020] [Accepted: 09/29/2020] [Indexed: 12/16/2022] Open
Abstract
D-amino acids have been known to exist in the human brain for nearly 40 years, and they continue to be a field of active study to today. This review article aims to give a concise overview of the recent advances in D-amino acid research as they relate to the brain and neurological disorders. This work has largely been focused on modulation of the N-methyl-D-aspartate (NMDA) receptor and its relationship to Alzheimer’s disease and Schizophrenia, but there has been a wealth of novel research which has elucidated a novel role for several D-amino acids in altering brain chemistry in a neuroprotective manner. D-amino acids which have no currently known activity in the brain but which have active derivatives will also be reviewed.
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Affiliation(s)
- James M. Seckler
- Department Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Correspondence:
| | - Stephen J. Lewis
- Department Pediatrics, Case Western Reserve University, Cleveland, OH 44106, USA;
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15
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Ortiz-Rodriguez JM, Martín-Cano FE, Ortega-Ferrusola C, Masot J, Redondo E, Gázquez A, Gil MC, Aparicio IM, Rojo-Domínguez P, Tapia JA, Rodriguez-Martínez H, Peña FJ. The incorporation of cystine by the soluble carrier family 7 member 11 (SLC7A11) is a component of the redox regulatory mechanism in stallion spermatozoa†. Biol Reprod 2020; 101:208-222. [PMID: 30998234 DOI: 10.1093/biolre/ioz069] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 02/20/2019] [Accepted: 04/17/2019] [Indexed: 01/17/2023] Open
Abstract
Oxidative stress is considered a major mechanism causing sperm damage during cryopreservation and storage, and underlies male factor infertility. Currently, oxidative stress is no longer believed to be caused only by the overproduction of reactive oxygen species, but rather by the deregulation of redox signaling and control mechanisms. With this concept in mind, here, we describe for the first time the presence of the soluble carrier family 7 member 11 (SLC7A11) antiporter, which exchanges extracellular cystine (Cyss) for intracellular glutamate, in stallion spermatozoa, as well as its impact on sperm function using the specific inhibitor sulfasalazine. Spermatozoa incubated with Cyss exhibited an increased intracellular GSH content compared with controls (P < 0.01): 50% in fresh extended stallion spermatozoa and 30% in frozen-thawed spermatozoa. This effect was prevented by the addition of sulfasalazine to the media. Cystine supplementation also reduced the oxidation-reduction potential of spermatozoa, with sulfasalazine only preventing this effect on fresh spermatozoa that were incubated for 3 h at 37°C, but not in frozen-thawed spermatozoa. While sulfasalazine reduced the motility of frozen-thawed spermatozoa, it increased motility in fresh samples. The present findings provide new and relevant data on the mechanism regulating the redox status of spermatozoa and suggest that a different redox regulatory mechanism exists in cryopreserved spermatozoa, thus providing new clues to improve current cryopreservation technologies and treat male factor infertility.
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Affiliation(s)
- José Manuel Ortiz-Rodriguez
- Laboratory of Equine Reproduction and Equine Spermatology, Veterinary Teaching Hospital, University of Extremadura, Cáceres, Spain
| | - Francisco E Martín-Cano
- Laboratory of Equine Reproduction and Equine Spermatology, Veterinary Teaching Hospital, University of Extremadura, Cáceres, Spain
| | - Cristina Ortega-Ferrusola
- Laboratory of Equine Reproduction and Equine Spermatology, Veterinary Teaching Hospital, University of Extremadura, Cáceres, Spain
| | - Javier Masot
- Laboratory of Equine Reproduction and Equine Spermatology, Veterinary Teaching Hospital, University of Extremadura, Cáceres, Spain
| | - Eloy Redondo
- Laboratory of Equine Reproduction and Equine Spermatology, Veterinary Teaching Hospital, University of Extremadura, Cáceres, Spain
| | - Antonio Gázquez
- Laboratory of Equine Reproduction and Equine Spermatology, Veterinary Teaching Hospital, University of Extremadura, Cáceres, Spain
| | - María C Gil
- Laboratory of Equine Reproduction and Equine Spermatology, Veterinary Teaching Hospital, University of Extremadura, Cáceres, Spain
| | - Inés M Aparicio
- Laboratory of Equine Reproduction and Equine Spermatology, Veterinary Teaching Hospital, University of Extremadura, Cáceres, Spain
| | - Patricia Rojo-Domínguez
- Laboratory of Equine Reproduction and Equine Spermatology, Veterinary Teaching Hospital, University of Extremadura, Cáceres, Spain
| | - José A Tapia
- Laboratory of Equine Reproduction and Equine Spermatology, Veterinary Teaching Hospital, University of Extremadura, Cáceres, Spain
| | - Heriberto Rodriguez-Martínez
- Department of Clinical and Experimental Medicine, Faculty of Medicine & Health Sciences, Linköping University, Linköping, Sweden
| | - Fernando J Peña
- Laboratory of Equine Reproduction and Equine Spermatology, Veterinary Teaching Hospital, University of Extremadura, Cáceres, Spain
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16
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Asc-1 Transporter (SLC7A10): Homology Models And Molecular Dynamics Insights Into The First Steps Of The Transport Mechanism. Sci Rep 2020; 10:3731. [PMID: 32111919 PMCID: PMC7048771 DOI: 10.1038/s41598-020-60617-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 02/14/2020] [Indexed: 12/02/2022] Open
Abstract
The alanine-serine-cysteine transporter Asc-1 regulates the synaptic availability of d-serine and glycine (the two co-agonists of the NMDA receptor) and is regarded as an important drug target. To shuttle the substrate from the extracellular space to the cytoplasm, this transporter undergoes multiple distinct conformational states. In this work, homology modeling, substrate docking and molecular dynamics simulations were carried out to learn more about the transition between the “outward-open” and “outward-open occluded” states. We identified a transition state involving the highly-conserved unwound TM6 region in which the Phe243 flips close to the d-serine substrate without major movements of TM6. This feature and those of other key residues are proposed to control the binding site and substrate translocation. Competitive inhibitors ACPP, LuAE00527 and SMLC were docked and their binding modes at the substrate binding site corroborated the key role played by Phe243 of TM6. For ACPP and LuAE00527, strong hydrophobic interactions with this residue hinder its mobility and prevent the uptake and the efflux of substrates. As for SMLC, the weaker interactions maintain the flexibility of Phe243 and the efflux process. Overall, we propose a molecular basis for the inhibition of substrate translocation of the Asc-1 transporter that should be valuable for rational drug design.
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17
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Torrecillas IR, Conde-Ceide S, de Lucas AI, Garcı́a Molina A, Trabanco AA, Lavreysen H, Pardo L, Tresadern G. Inhibition of the Alanine-Serine-Cysteine-1 Transporter by BMS-466442. ACS Chem Neurosci 2019; 10:2510-2517. [PMID: 30821959 DOI: 10.1021/acschemneuro.9b00019] [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] [Indexed: 12/20/2022] Open
Abstract
Experiment and modeling were combined to understand inhibition of the alanine-serine-cysteine-1 (asc1) transporter. The structure-activity relationship (SAR) was explored with synthesis of analogues of BMS-466442. Direct target interaction and binding site location between TM helices 6 and 10 were confirmed via site directed mutagenesis. Computational modeling suggested the inhibitor binds via competitive occupation of the orthosteric site while also blocking the movement of TM helices that are required for transport.
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Affiliation(s)
- Ivan R. Torrecillas
- Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina, Universitat Autonoma de Barcelona, 08193, Bellaterra, Spain
| | - Susana Conde-Ceide
- Medicinal Chemistry, Janssen Research & Development, Calle Jarama 75A, Toledo 45007, Spain
| | - Ana Isabel de Lucas
- Medicinal Chemistry, Janssen Research & Development, Calle Jarama 75A, Toledo 45007, Spain
| | | | - Andrés A. Trabanco
- Medicinal Chemistry, Janssen Research & Development, Calle Jarama 75A, Toledo 45007, Spain
| | | | - Leonardo Pardo
- Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina, Universitat Autonoma de Barcelona, 08193, Bellaterra, Spain
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18
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Oke Y, Miwakeichi F, Oku Y, Hirrlinger J, Hülsmann S. Cell Type-Dependent Activation Sequence During Rhythmic Bursting in the PreBötzinger Complex in Respiratory Rhythmic Slices From Mice. Front Physiol 2018; 9:1219. [PMID: 30233397 PMCID: PMC6129845 DOI: 10.3389/fphys.2018.01219] [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: 05/16/2018] [Accepted: 08/13/2018] [Indexed: 11/13/2022] Open
Abstract
Spontaneous respiratory rhythmic burst activity can be preserved in the preBötzinger Complex (preBötC) of rodent medullary transverse slices. It is known, that the activation sequence of inspiratory neurons in the preBötC stochastically varies from cycle to cycle. To test whether the activation timing of an inspiratory neuron depends on its neurotransmitter, we performed calcium imaging of preBötC neurons using double-transgenic mice expressing EGFP in GlyT2+ neurons and tdTomato in GAD65+ neurons. Five types of inspiratory neurons were identified using the fluorescence protein expression and the maximum cross-correlation coefficient between neuronal calcium fluctuation and field potential. Regarding the activation sequence, irregular type putative excitatory (GlyT2-/GAD65-) neurons and irregular type glycinergic (GlyT2+/GAD65-) neurons tended to be activated early, while regular type putative excitatory neurons, regular type glycinergic neurons tended to be activated later. In conclusion, the different cell types define a general framework for the stochastically changing activation sequence of inspiratory neurons in the preBötC.
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Affiliation(s)
- Yoshihiko Oke
- Division of Physiome, Department of Physiology, Hyogo College of Medicine, Nishinomiya, Japan
| | - Fumikazu Miwakeichi
- Department of Statistical Modeling, The Institute of Statistical Mathematics, Tachikawa, Japan.,Department of Statistical Science, School of Multidisciplinary Sciences, The Graduate University for Advanced Studies, Hayama, Japan
| | - Yoshitaka Oku
- Division of Physiome, Department of Physiology, Hyogo College of Medicine, Nishinomiya, Japan
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Leipzig, Germany.,Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Swen Hülsmann
- Clinic for Anesthesiology, University Medical Center Göttingen, Göttingen, Germany.,Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany
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