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Nogueira M, Golbert DCF, Landeira B, Leão RN. Laser Capture Microdissection Optimization for High-Quality RNA in Mouse Brain Tissue. Curr Protoc 2022; 2:e457. [PMID: 35822833 DOI: 10.1002/cpz1.457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Laser Capture Microdissection (LCM) is a method that allows one to select and dissect well-defined structures, specific cell subpopulations, or even single cells from different types of tissue for subsequent extraction of DNA, RNA, or proteins. Its precision allows the dissection of specific groups of cells, avoiding unwanted cells. However, despite its efficiency, several steps can affect the sample RNA integrity. RNA instability represents a challenge in the LCM method, and low RNA integrity can introduce biases, as different transcripts often have different degradation rates. Here we describe an optimized protocol to provide good-concentration and high-quality RNA from specific structures: dentate gyrus and CA1 in the hippocampus, basolateral amygdala, and anterior cingulate cortex of mouse brain tissue. However, the protocol is applicable to other areas of interest. © 2022 Wiley Periodicals LLC. Basic Protocol: Laser capture microdissection of mouse brain tissue.
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Affiliation(s)
- Margareth Nogueira
- Neurodynamics Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Daiane C F Golbert
- Neurodynamics Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Bruna Landeira
- Neurodynamics Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Richardson N Leão
- Neurodynamics Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil
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2
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Peixoto HM, Cruz RMS, Moulin TC, Leão RN. Modeling the Effect of Temperature on Membrane Response of Light Stimulation in Optogenetically-Targeted Neurons. Front Comput Neurosci 2020; 14:5. [PMID: 32116619 PMCID: PMC7010719 DOI: 10.3389/fncom.2020.00005] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 01/14/2020] [Indexed: 01/03/2023] Open
Abstract
Optogenetics is revolutionizing Neuroscience, but an often neglected effect of light stimulation of the brain is the generation of heat. In extreme cases, light-generated heat kills neurons, but mild temperature changes alter neuronal function. To date, most in vivo experiments rely on light stimulation of neural tissue using fiber-coupled lasers of various wavelengths. Brain tissue is irradiated with high light power that can be deleterious to neuronal function. Furthermore, absorbed light generates heat that can lead to permanent tissue damage and affect neuronal excitability. Thus, light alone can generate effects in neuronal function that are unrelated to the genuine "optogenetic effect." In this work, we perform a theoretical analysis to investigate the effects of heat transfer in rodent brain tissue for standard optogenetic protocols. More precisely, we first use the Kubelka-Munk model for light propagation in brain tissue to observe the absorption phenomenon. Then, we model the optothermal effect considering the common laser wavelengths (473 and 593 nm) used in optogenetic experiments approaching the time/space numerical solution of Pennes' bio-heat equation with the Finite Element Method. Finally, we then modeled channelrhodopsin-2 in a single and spontaneous-firing neuron to explore the effect of heat in light stimulated neurons. We found that, at commonly used light intensities, laser radiation considerably increases the temperature in the surrounding tissue. This effect alters action potential size and shape and causes an increase in spontaneous firing frequency in a neuron model. However, the shortening of activation time constants generated by heat in the single firing neuron model produces action potential failures in response to light stimulation. We also found changes in the power spectrum density and a reduction in the time required for synchronization in an interneuron network model of gamma oscillations. Our findings indicate that light stimulation with intensities used in optogenetic experiments may affect neuronal function not only by direct excitation of light sensitive ion channels and/or pumps but also by generating heat. This approach serves as a guide to design optogenetic experiments that minimize the role of tissue heating in the experimental outcome.
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Affiliation(s)
- Helton M. Peixoto
- School of Science and Technology (ECT), Federal University of Rio Grande do Norte (UFRN), Natal, Brazil
- Neurodynamics Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil
- Developmental Genetics Unit, Neurodynamics Lab, Department of Neuroscience, Uppsala, Sweden
| | - Rossana M. S. Cruz
- Electrical Engineering Department, Federal Institute of Paraiba (IFPB), Joao Pessoa, Brazil
| | - Thiago C. Moulin
- Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Richardson N. Leão
- Neurodynamics Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil
- Developmental Genetics Unit, Neurodynamics Lab, Department of Neuroscience, Uppsala, Sweden
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3
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Winne J, Boerner BC, Malfatti T, Brisa E, Doerl J, Nogueira I, Leão KE, Leão RN. Anxiety-like behavior induced by salicylate depends on age and can be prevented by a single dose of 5-MeO-DMT. Exp Neurol 2020; 326:113175. [PMID: 31923390 DOI: 10.1016/j.expneurol.2020.113175] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 12/23/2019] [Accepted: 01/06/2020] [Indexed: 11/16/2022]
Abstract
Salicylate intoxication is a cause of tinnitus and comorbidly associated with anxiety in humans. In a previous work, we showed that salicylate induces anxiety-like behavior and hippocampal type 2 theta oscillations (theta2) in mice. Here we investigate if the anxiogenic effect of salicylate is dependent on age and previous tinnitus experience. We also tested whether a single dose of DMT can prevent this effect. Using microwire electrode arrays, we recorded local field potential in young (4-5- month-old) and old (11-13-month-old) mice to study the electrophysiological effect of tinnitus in the ventral hippocampus (vHipp) and medial prefrontal cortex (mPFC) in an open field arena and elevated plus maze 1h after salicylate (300mg/kg) injection. We found that anxiety-like behavior and increase in theta2 oscillations (4-6 Hz), following salicylate pre-treatment, only occurs in young (normal hearing) mice. We also show that theta2 and slow gamma oscillations increase in the vHipp and mPFC in a complementary manner during anxiety tests in the presence of salicylate. Finally, we show that pre-treating mice with a single dose of the hallucinogenic 5-MeO-DMT prevents anxiety-like behavior and the increase in theta2 and slow gamma oscillations after salicylate injection in normal hearing young mice. This work further support the hypothesis that anxiety-like behavior after salicylate injection is triggered by tinnitus and require normal hearing. Moreover, our results show that hallucinogenic compounds can be effective in treating tinnitus-related anxiety.
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Affiliation(s)
- Jessica Winne
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal/RN, Brazil; Developmental Genetics Unit, Department of Neuroscience, Uppsala University, Husarg 3, Uppsala 75234, Sweden
| | - Barbara C Boerner
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal/RN, Brazil
| | - Thawann Malfatti
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal/RN, Brazil
| | - Elis Brisa
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal/RN, Brazil
| | - Jhulimar Doerl
- Neural Development and Environment Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal, RN, Brazil
| | - Ingrid Nogueira
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal/RN, Brazil
| | - Katarina E Leão
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal/RN, Brazil
| | - Richardson N Leão
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal/RN, Brazil; Neural Development and Environment Lab, Brain Institute, Federal University of the Rio Grande do Norte, Av. Nascimento de Castro 2155, 59560-450 Natal, RN, Brazil.
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Hilscher MM, Nogueira I, Mikulovic S, Kullander K, Leão RN, Leão KE. Chrna2‐OLM interneurons display different membrane properties and h‐current magnitude depending on dorsoventral location. Hippocampus 2019; 29:1224-1237. [DOI: 10.1002/hipo.23134] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 06/03/2019] [Accepted: 06/08/2019] [Indexed: 12/21/2022]
Affiliation(s)
- Markus M. Hilscher
- Brain InstituteFederal University of Rio Grande do Norte Natal Rio Grande do Norte Brazil
- Institute for Analysis and Scientific ComputingVienna University of Technology Vienna Austria
- Unit of Developmental Genetics, Department of NeuroscienceUppsala University Uppsala Sweden
| | - Ingrid Nogueira
- Brain InstituteFederal University of Rio Grande do Norte Natal Rio Grande do Norte Brazil
| | - Sanja Mikulovic
- Unit of Developmental Genetics, Department of NeuroscienceUppsala University Uppsala Sweden
| | - Klas Kullander
- Unit of Developmental Genetics, Department of NeuroscienceUppsala University Uppsala Sweden
| | - Richardson N. Leão
- Brain InstituteFederal University of Rio Grande do Norte Natal Rio Grande do Norte Brazil
- Unit of Developmental Genetics, Department of NeuroscienceUppsala University Uppsala Sweden
| | - Katarina E. Leão
- Brain InstituteFederal University of Rio Grande do Norte Natal Rio Grande do Norte Brazil
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Lima da Cruz RV, Moulin TC, Petiz LL, Leão RN. Corrigendum: A Single Dose of 5-MeO-DMT Stimulates Cell Proliferation, Neuronal Survivability, Morphological and Functional Changes in Adult Mice Ventral Dentate Gyrus. Front Mol Neurosci 2019; 12:79. [PMID: 31019450 PMCID: PMC6459282 DOI: 10.3389/fnmol.2019.00079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/11/2019] [Indexed: 11/30/2022] Open
Affiliation(s)
| | - Thiago C Moulin
- Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Lyvia Lintzmaier Petiz
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Natal, Brazil
| | - Richardson N Leão
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Natal, Brazil.,Developmental Genetics, Department of Neuroscience, Uppsala University, Uppsala, Sweden
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Oliveira RB, Petiz LL, Lim R, Lipski J, Gravina FS, Brichta AM, Callister RJ, Leão RN, Helden DF. Crosstalk between mitochondria, calcium channels and actin cytoskeleton modulates noradrenergic activity of locus coeruleus neurons. J Neurochem 2019; 149:471-487. [DOI: 10.1111/jnc.14692] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/22/2019] [Accepted: 02/28/2019] [Indexed: 12/21/2022]
Affiliation(s)
- Ramatis B. Oliveira
- School of Biomedical Sciences and Pharmacy University of Newcastle and Hunter Medical Research Institute Callaghan NSW Australia
- Health and Medical Research Group School of Medicine University of the Taquari Valley ‐ Univates Lajeado RS Brazil
- Bairro Universitário Lajeado RS Brazil
| | - Lyvia L. Petiz
- School of Biomedical Sciences and Pharmacy University of Newcastle and Hunter Medical Research Institute Callaghan NSW Australia
- Brain Institute Federal University of Rio Grande do Norte Natal Brazil
| | - Rebecca Lim
- School of Biomedical Sciences and Pharmacy University of Newcastle and Hunter Medical Research Institute Callaghan NSW Australia
| | - Janusz Lipski
- Faculty of Medical and Health Sciences University of Auckland Auckland New Zealand
| | - Fernanda S. Gravina
- School of Biomedical Sciences and Pharmacy University of Newcastle and Hunter Medical Research Institute Callaghan NSW Australia
| | - Alan M. Brichta
- School of Biomedical Sciences and Pharmacy University of Newcastle and Hunter Medical Research Institute Callaghan NSW Australia
| | - Robert J. Callister
- School of Biomedical Sciences and Pharmacy University of Newcastle and Hunter Medical Research Institute Callaghan NSW Australia
| | - Richardson N. Leão
- Brain Institute Federal University of Rio Grande do Norte Natal Brazil
- The Beijer Laboratory for Gene and Neurosciences Department of Neuroscience Uppsala University Uppsala Sweden
| | - Dirk F. Helden
- School of Biomedical Sciences and Pharmacy University of Newcastle and Hunter Medical Research Institute Callaghan NSW Australia
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Moulin TC, Petiz LL, Rayêe D, Winne J, Maia RG, Lima da Cruz RV, Amaral OB, Leão RN. Chronic in vivo optogenetic stimulation modulates neuronal excitability, spine morphology, and Hebbian plasticity in the mouse hippocampus. Hippocampus 2019; 29:755-761. [DOI: 10.1002/hipo.23080] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 12/19/2018] [Accepted: 01/26/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Thiago C. Moulin
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro; Rio de Janeiro Brazil
- Brain Institute, Federal University of Rio Grande do Norte; Rio Grande do Norte Brazil
| | - Lyvia L. Petiz
- Brain Institute, Federal University of Rio Grande do Norte; Rio Grande do Norte Brazil
| | - Danielle Rayêe
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro; Rio de Janeiro Brazil
| | - Jessica Winne
- Brain Institute, Federal University of Rio Grande do Norte; Rio Grande do Norte Brazil
| | - Roberto G. Maia
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro; Rio de Janeiro Brazil
| | | | - Olavo B. Amaral
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro; Rio de Janeiro Brazil
| | - Richardson N. Leão
- Brain Institute, Federal University of Rio Grande do Norte; Rio Grande do Norte Brazil
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8
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Winne J, Franzon R, de Miranda A, Malfatti T, Patriota J, Mikulovic S, Leão KE, Leão RN. Salicylate induces anxiety-like behavior and slow theta oscillation and abolishes the relationship between running speed and fast theta oscillation frequency. Hippocampus 2018; 29:15-25. [PMID: 30152905 DOI: 10.1002/hipo.23021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 07/27/2018] [Accepted: 08/13/2018] [Indexed: 01/09/2023]
Abstract
Salicylate intoxication is a cause of tinnitus in humans and it is often used to produce tinnitus-like perception in animal models. Here, we assess whether salicylate induces anxiety-like electrophysiological and behavioral signs. Using microwire electrode arrays, we recorded local field potential in the ventral and, in some experiments dorsal hippocampus, in an open field arena 1 hr after salicylate (300 mg/kg) injection. We found that animals treated with salicylate moved dramatically less than saline treated animals. Salicylate-treated animals showed a strong 4-6 Hz (type 2) oscillation in the ventral hippocampus (with smaller peaks in dorsal hippocampus electrodes). Coherence in the 4-6 Hz-theta band was low in the ventral and dorsal hippocampus when compared to movement-related theta coherence (7-10 Hz). Moreover, movement related theta oscillation frequency decreased and its dependency on running speed was abolished. Our results suggest that salicylate-induced theta is mostly restricted to the ventral hippocampus. Slow theta has been classically associated to anxiety-like behaviors. Here, we show that salicylate application can consistently generate low frequency theta in the ventral hippocampus. Tinnitus and anxiety show strong comorbidity and the increase in ventral hippocampus low frequency theta could be part of this association.
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Affiliation(s)
- Jessica Winne
- Neurodynamics Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Rafael Franzon
- Neurodynamics Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Aron de Miranda
- Neurodynamics Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Thawann Malfatti
- Neurodynamics Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - João Patriota
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Sanja Mikulovic
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Katarina E Leão
- Neurodynamics Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Richardson N Leão
- Neurodynamics Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.,Department of Neuroscience, Uppsala University, Uppsala, Sweden
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9
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Lima da Cruz RV, Moulin TC, Petiz LL, Leão RN. A Single Dose of 5-MeO-DMT Stimulates Cell Proliferation, Neuronal Survivability, Morphological and Functional Changes in Adult Mice Ventral Dentate Gyrus. Front Mol Neurosci 2018; 11:312. [PMID: 30233313 PMCID: PMC6131656 DOI: 10.3389/fnmol.2018.00312] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 08/15/2018] [Indexed: 11/13/2022] Open
Abstract
The subgranular zone (SGZ) of dentate gyrus (DG) is one of the few regions in which neurogenesis is maintained throughout adulthood. It is believed that newborn neurons in this region encode temporal information about partially overlapping contextual memories. The 5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a naturally occurring compound capable of inducing a powerful psychedelic state. Recently, it has been suggested that DMT analogs may be used in the treatment of mood disorders. Due to the strong link between altered neurogenesis and mood disorders, we tested whether 5-MeO-DMT is capable of increasing DG cell proliferation. We show that a single intracerebroventricular (ICV) injection of 5-MeO-DMT increases the number of Bromodeoxyuridine (BrdU+) cells in adult mice DG. Moreover, using a transgenic animal expressing tamoxifen-dependent Cre recombinase under doublecortin promoter, we found that 5 Meo-DMT treated mice had a higher number of newborn DG Granule cells (GC). We also showed that these DG GC have more complex dendritic morphology after 5-MeO-DMT. Lastly, newborn GC treated with 5-MeO-DMT, display shorter afterhyperpolarization (AHP) potentials and higher action potential (AP) threshold compared. Our findings show that 5-MeO-DMT affects neurogenesis and this effect may contribute to the known antidepressant properties of DMT-derived compounds.
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Affiliation(s)
| | - Thiago C Moulin
- Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Lyvia Lintzmaier Petiz
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Natal, Brazil
| | - Richardson N Leão
- Neurodynamics Lab, Brain Institute, Federal University of the Rio Grande do Norte, Natal, Brazil.,Developmental Genetics, Department of Neuroscience, Uppsala University, Uppsala, Sweden
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10
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Siwani S, França AS, Mikulovic S, Reis A, Hilscher MM, Edwards SJ, Leão RN, Tort AB, Kullander K. OLMα2 Cells Bidirectionally Modulate Learning. Neuron 2018; 99:404-412.e3. [DOI: 10.1016/j.neuron.2018.06.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 05/17/2018] [Accepted: 06/13/2018] [Indexed: 12/21/2022]
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11
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Araújo JADM, Hilscher MM, Marques-Coelho D, Golbert DCF, Cornelio DA, Batistuzzo de Medeiros SR, Leão RN, Costa MR. Direct Reprogramming of Adult Human Somatic Stem Cells Into Functional Neurons Using Sox2, Ascl1, and Neurog2. Front Cell Neurosci 2018; 12:155. [PMID: 29937717 PMCID: PMC6003093 DOI: 10.3389/fncel.2018.00155] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 05/17/2018] [Indexed: 12/21/2022] Open
Abstract
Reprogramming of somatic cells into induced pluripotent stem cells (iPS) or directly into cells from a different lineage, including neurons, has revolutionized research in regenerative medicine in recent years. Mesenchymal stem cells are good candidates for lineage reprogramming and autologous transplantation, since they can be easily isolated from accessible sources in adult humans, such as bone marrow and dental tissues. Here, we demonstrate that expression of the transcription factors (TFs) SRY (sex determining region Y)-box 2 (Sox2), Mammalian achaete-scute homolog 1 (Ascl1), or Neurogenin 2 (Neurog2) is sufficient for reprogramming human umbilical cord mesenchymal stem cells (hUCMSC) into induced neurons (iNs). Furthermore, the combination of Sox2/Ascl1 or Sox2/Neurog2 is sufficient to reprogram up to 50% of transfected hUCMSCs into iNs showing electrical properties of mature neurons and establishing synaptic contacts with co-culture primary neurons. Finally, we show evidence supporting the notion that different combinations of TFs (Sox2/Ascl1 and Sox2/Neurog2) may induce multiple and overlapping neuronal phenotypes in lineage-reprogrammed iNs, suggesting that neuronal fate is determined by a combination of signals involving the TFs used for reprogramming but also the internal state of the converted cell. Altogether, the data presented here contribute to the advancement of techniques aiming at obtaining specific neuronal phenotypes from lineage-converted human somatic cells to treat neurological disorders.
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Affiliation(s)
| | - Markus M Hilscher
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Diego Marques-Coelho
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil.,Bioinformatics Multidisciplinary Environment, IMD, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Daiane C F Golbert
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Deborah A Cornelio
- Laboratório de Biologia Molecular e Genômica, Centro de Biociências, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Silvia R Batistuzzo de Medeiros
- Laboratório de Biologia Molecular e Genômica, Centro de Biociências, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Richardson N Leão
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Marcos R Costa
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil
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12
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Hilscher MM, Leão RN, Edwards SJ, Leão KE, Kullander K. Chrna2-Martinotti Cells Synchronize Layer 5 Type A Pyramidal Cells via Rebound Excitation. PLoS Biol 2017; 15:e2001392. [PMID: 28182735 PMCID: PMC5300109 DOI: 10.1371/journal.pbio.2001392] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 01/05/2017] [Indexed: 12/22/2022] Open
Abstract
Martinotti cells are the most prominent distal dendrite–targeting interneurons in the cortex, but their role in controlling pyramidal cell (PC) activity is largely unknown. Here, we show that the nicotinic acetylcholine receptor α2 subunit (Chrna2) specifically marks layer 5 (L5) Martinotti cells projecting to layer 1. Furthermore, we confirm that Chrna2-expressing Martinotti cells selectively target L5 thick-tufted type A PCs but not thin-tufted type B PCs. Using optogenetic activation and inhibition, we demonstrate how Chrna2-Martinotti cells robustly reset and synchronize type A PCs via slow rhythmic burst activity and rebound excitation. Moreover, using optical feedback inhibition, in which PC spikes controlled the firing of surrounding Chrna2-Martinotti cells, we found that neighboring PC spike trains became synchronized by Martinotti cell inhibition. Together, our results show that L5 Martinotti cells participate in defined cortical circuits and can synchronize PCs in a frequency-dependent manner. These findings suggest that Martinotti cells are pivotal for coordinated PC activity, which is involved in cortical information processing and cognitive control. Cognitive functions and information processing are linked to the coordination of neuronal events and activities. This coordination is achieved through the synchronization of neuronal signals within subnetworks. Local networks contain different types of nerve cells, each of them playing distinct roles in the synchronization mechanism. To understand how synchronization is initiated and maintained, we have identified one of the key players using genetic strategies; we have identified a subtype of nicotine receptors uniquely expressed in cortical Martinotti cells. Because of their architecture and connection properties, Martinotti cells are able to synchronize ongoing activity of unconnected pyramidal cells (PCs). We show that this mechanism only applies to one subtype of PCs, thereby demonstrating that Martinotti cell inhibition is not spread randomly. By testing optimal firing patterns of Martinotti cells, we are able to coordinate the firing of this specific PC subtype over longer periods of time, showing how one unique interneuron is contributing to information processing.
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Affiliation(s)
- Markus M. Hilscher
- Unit of Developmental Genetics, Department of Neuroscience, Uppsala University, Uppsala, Sweden
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
- * E-mail: (MMH); (KK)
| | - Richardson N. Leão
- Unit of Developmental Genetics, Department of Neuroscience, Uppsala University, Uppsala, Sweden
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Steven J. Edwards
- Unit of Developmental Genetics, Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Katarina E. Leão
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Klas Kullander
- Unit of Developmental Genetics, Department of Neuroscience, Uppsala University, Uppsala, Sweden
- * E-mail: (MMH); (KK)
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13
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Mikulovic S, Pupe S, Peixoto HM, Do Nascimento GC, Kullander K, Tort ABL, Leão RN. On the photovoltaic effect in local field potential recordings. Neurophotonics 2016; 3:015002. [PMID: 26835485 PMCID: PMC4717288 DOI: 10.1117/1.nph.3.1.015002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 12/01/2015] [Indexed: 06/02/2023]
Abstract
Optogenetics allows light activation of genetically defined cell populations and the study of their link to specific brain functions. While it is a powerful method that has revolutionized neuroscience in the last decade, the shortcomings of directly stimulating electrodes and living tissue with light have been poorly characterized. Here, we assessed the photovoltaic effects in local field potential (LFP) recordings of the mouse hippocampus. We found that light leads to several artifacts that resemble genuine LFP features in animals with no opsin expression, such as stereotyped peaks at the power spectrum, phase shifts across different recording channels, coupling between low and high oscillation frequencies, and sharp signal deflections that are detected as spikes. Further, we tested how light stimulation affected hippocampal LFP recordings in mice expressing channelrhodopsin 2 in parvalbumin neurons (PV/ChR2 mice). Genuine oscillatory activity at the frequency of light stimulation could not be separated from light-induced artifacts. In addition, light stimulation in PV/ChR2 mice led to an overall decrease in LFP power. Thus, genuine LFP changes caused by the stimulation of specific cell populations may be intermingled with spurious changes caused by photovoltaic effects. Our data suggest that care should be taken in the interpretation of electrophysiology experiments involving light stimulation.
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Affiliation(s)
- Sanja Mikulovic
- Uppsala University, Unit of Developmental Genetics, Department of Neuroscience, Husargatan 3, 75237, Uppsala, Sweden
| | - Stefano Pupe
- Uppsala University, Unit of Developmental Genetics, Department of Neuroscience, Husargatan 3, 75237, Uppsala, Sweden
- Federal University of Rio Grande do Norte, Brain Institute, Avenida Nascimento de Castro, 2155, 59056-450, Natal-RN, Brazil
| | - Helton Maia Peixoto
- Federal University of Rio Grande do Norte, Brain Institute, Avenida Nascimento de Castro, 2155, 59056-450, Natal-RN, Brazil
| | - George C. Do Nascimento
- Federal University of Rio Grande do Norte, Department of Biomedical Engineering, Avenida Senador Salgado Filho, 300, 59078-970, Natal-RN, Brazil
| | - Klas Kullander
- Uppsala University, Unit of Developmental Genetics, Department of Neuroscience, Husargatan 3, 75237, Uppsala, Sweden
| | - Adriano B. L. Tort
- Federal University of Rio Grande do Norte, Brain Institute, Avenida Nascimento de Castro, 2155, 59056-450, Natal-RN, Brazil
| | - Richardson N. Leão
- Uppsala University, Unit of Developmental Genetics, Department of Neuroscience, Husargatan 3, 75237, Uppsala, Sweden
- Federal University of Rio Grande do Norte, Brain Institute, Avenida Nascimento de Castro, 2155, 59056-450, Natal-RN, Brazil
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Mikulovic S, Restrepo CE, Hilscher MM, Kullander K, Leão RN. Novel markers for OLM interneurons in the hippocampus. Front Cell Neurosci 2015; 9:201. [PMID: 26082683 PMCID: PMC4451365 DOI: 10.3389/fncel.2015.00201] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 05/10/2015] [Indexed: 12/21/2022] Open
Affiliation(s)
- Sanja Mikulovic
- Unit of Developmental Genetics, Department of Neuroscience, Uppsala University Uppsala, Sweden
| | - C Ernesto Restrepo
- Unit of Developmental Genetics, Department of Neuroscience, Uppsala University Uppsala, Sweden
| | - Markus M Hilscher
- Unit of Developmental Genetics, Department of Neuroscience, Uppsala University Uppsala, Sweden ; Neurodynamics Lab, Brain Institute, Federal University of Rio Grande do Norte Natal-RN, Brazil
| | - Klas Kullander
- Unit of Developmental Genetics, Department of Neuroscience, Uppsala University Uppsala, Sweden
| | - Richardson N Leão
- Unit of Developmental Genetics, Department of Neuroscience, Uppsala University Uppsala, Sweden ; Neurodynamics Lab, Brain Institute, Federal University of Rio Grande do Norte Natal-RN, Brazil
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15
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Patra K, Lyons DJ, Bauer P, Hilscher MM, Sharma S, Leão RN, Kullander K. A role for solute carrier family 10 member 4, or vesicular aminergic-associated transporter, in structural remodelling and transmitter release at the mouse neuromuscular junction. Eur J Neurosci 2014; 41:316-27. [DOI: 10.1111/ejn.12790] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Revised: 10/14/2014] [Accepted: 10/17/2014] [Indexed: 12/27/2022]
Affiliation(s)
| | - David J. Lyons
- Department of Neuroscience; Uppsala University; Uppsala Sweden
| | - Pavol Bauer
- Department of Neuroscience; Uppsala University; Uppsala Sweden
| | - Markus M. Hilscher
- Department of Neuroscience; Uppsala University; Uppsala Sweden
- The Beijer Laboratory for Gene and Neurosciences; Uppsala Sweden
- Brain Institute; Federal University of Rio Grande do Norte; Natal Brazil
| | - Swati Sharma
- Department of Neuroscience; Uppsala University; Uppsala Sweden
| | - Richardson N. Leão
- Department of Neuroscience; Uppsala University; Uppsala Sweden
- The Beijer Laboratory for Gene and Neurosciences; Uppsala Sweden
- Brain Institute; Federal University of Rio Grande do Norte; Natal Brazil
| | - Klas Kullander
- Department of Neuroscience; Uppsala University; Uppsala Sweden
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16
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Leão RN, Targino ZH, Colom LV, Fisahn A. Interconnection and synchronization of neuronal populations in the mouse medial septum/diagonal band of Broca. J Neurophysiol 2014; 113:971-80. [PMID: 25392162 DOI: 10.1152/jn.00367.2014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The medial septum/diagonal band of Broca (MS/DBB) is crucial for hippocampal theta rhythm generation (4-12 Hz). However, the mechanisms behind theta rhythmogenesis are still under debate. The MS/DBB consists, in its majority, of three neuronal populations that use acetylcholine, GABA, or glutamate as neurotransmitter. While the firing patterns of septal neurons enable the MS/DBB to generate rhythmic output critical for the generation of the hippocampal theta rhythm, the ability to synchronize these action potentials is dependent on the interconnectivity between the three major MS/DBB neuronal populations, yet little is known about intraseptal connections. Here we assessed the connectivity between pairs of MS/DBB neurons with paired patch-clamp recordings. We found that glutamatergic and GABAergic neurons provide intraseptal connections and produce sizable currents in MS/DBB postsynaptic cells. We also analyzed linear and nonlinear relationships between the action potentials fired by pairs of neurons belonging to various MS/DBB neuronal populations. Our results show that while the synchrony index for action potential firing was significantly higher in pairs of GABAergic neurons, coherence of action potential firing in the theta range was similarly low in all pairs analyzed. Recurrence analysis demonstrated that individual action potentials were more recurrent in cholinergic neurons than in other cell types. Implementing sparse connectivity in a computer model of the MS/DBB network reproduced our experimental data. We conclude that the interplay between the intrinsic membrane properties of different MS/DBB neuronal populations and the connectivity among these populations underlie the ability of the MS/DBB network to critically contribute to hippocampal theta rhythmogenesis.
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Affiliation(s)
- Richardson N Leão
- The Beijer Laboratory for Gene and Neurosciences, Department of Neuroscience, Uppsala University, Uppsala, Sweden; Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Zé H Targino
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Luis V Colom
- Center for Biomedical Studies, the University of Texas at Brownsville, Texas; and
| | - André Fisahn
- Neuronal Oscillations Laboratory, Division of Neurogeriatrics, Center for Alzheimer Research, Department NVS, Karolinska Institutet, Stockholm, Sweden
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17
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Schweizer N, Pupe S, Arvidsson E, Nordenankar K, Smith-Anttila CJA, Mahmoudi S, Andrén A, Dumas S, Rajagopalan A, Lévesque D, Leão RN, Wallén-Mackenzie Å. Limiting glutamate transmission in a Vglut2-expressing subpopulation of the subthalamic nucleus is sufficient to cause hyperlocomotion. Proc Natl Acad Sci U S A 2014; 111:7837-42. [PMID: 24821804 PMCID: PMC4040590 DOI: 10.1073/pnas.1323499111] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The subthalamic nucleus (STN) is a key area of the basal ganglia circuitry regulating movement. We identified a subpopulation of neurons within this structure that coexpresses Vglut2 and Pitx2, and by conditional targeting of this subpopulation we reduced Vglut2 expression levels in the STN by 40%, leaving Pitx2 expression intact. This reduction diminished, yet did not eliminate, glutamatergic transmission in the substantia nigra pars reticulata and entopeduncular nucleus, two major targets of the STN. The knockout mice displayed hyperlocomotion and decreased latency in the initiation of movement while preserving normal gait and balance. Spatial cognition, social function, and level of impulsive choice also remained undisturbed. Furthermore, these mice showed reduced dopamine transporter binding and slower dopamine clearance in vivo, suggesting that Vglut2-expressing cells in the STN regulate dopaminergic transmission. Our results demonstrate that altering the contribution of a limited population within the STN is sufficient to achieve results similar to STN lesions and high-frequency stimulation, but with fewer side effects.
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Affiliation(s)
- Nadine Schweizer
- Units of Functional Neurobiology andDevelopmental Genetics, Department of Neuroscience, Biomedical Center, Uppsala University, S-751 24 Uppsala, Sweden
| | - Stéfano Pupe
- Units of Functional Neurobiology andDevelopmental Genetics, Department of Neuroscience, Biomedical Center, Uppsala University, S-751 24 Uppsala, Sweden;Brain Institute, Federal University of Rio Grande do Norte, 2155-59056-450 Natal-RN, Brazil
| | - Emma Arvidsson
- Units of Functional Neurobiology andDevelopmental Genetics, Department of Neuroscience, Biomedical Center, Uppsala University, S-751 24 Uppsala, Sweden
| | - Karin Nordenankar
- Units of Functional Neurobiology andDevelopmental Genetics, Department of Neuroscience, Biomedical Center, Uppsala University, S-751 24 Uppsala, Sweden
| | - Casey J A Smith-Anttila
- Units of Functional Neurobiology andDevelopmental Genetics, Department of Neuroscience, Biomedical Center, Uppsala University, S-751 24 Uppsala, Sweden
| | - Souha Mahmoudi
- Faculty of Pharmacy, Université de Montréal, Montréal, QC, Canada H3C 3J7; and
| | - Anna Andrén
- Units of Functional Neurobiology andDevelopmental Genetics, Department of Neuroscience, Biomedical Center, Uppsala University, S-751 24 Uppsala, Sweden
| | | | - Aparna Rajagopalan
- Units of Functional Neurobiology andDevelopmental Genetics, Department of Neuroscience, Biomedical Center, Uppsala University, S-751 24 Uppsala, Sweden
| | - Daniel Lévesque
- Faculty of Pharmacy, Université de Montréal, Montréal, QC, Canada H3C 3J7; and
| | - Richardson N Leão
- Developmental Genetics, Department of Neuroscience, Biomedical Center, Uppsala University, S-751 24 Uppsala, Sweden;Brain Institute, Federal University of Rio Grande do Norte, 2155-59056-450 Natal-RN, Brazil
| | - Åsa Wallén-Mackenzie
- Units of Functional Neurobiology andDevelopmental Genetics, Department of Neuroscience, Biomedical Center, Uppsala University, S-751 24 Uppsala, Sweden;
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Hilscher MM, Leão KE, Leão RN. Synchronization through nonreciprocal connections in a hybrid hippocampus microcircuit. Front Neural Circuits 2013; 7:120. [PMID: 23888129 PMCID: PMC3719444 DOI: 10.3389/fncir.2013.00120] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 07/01/2013] [Indexed: 11/18/2022] Open
Abstract
Synchronization among neurons is thought to arise from the interplay between excitation and inhibition; however, the connectivity rules that contribute to synchronization are still unknown. We studied these issues in hippocampal CA1 microcircuits using paired patch clamp recordings and real time computing. By virtually connecting a model interneuron with two pyramidal cells (PCs), we were able to test the importance of connectivity in synchronizing pyramidal cell activity. Our results show that a circuit with a nonreciprocal connection between pyramidal cells and no feedback from PCs to the virtual interneuron produced the greatest level of synchronization and mutual information between PC spiking activity. Moreover, we investigated the role of intrinsic membrane properties contributing to synchronization where the application of a specific ion channel blocker, ZD7288 dramatically impaired PC synchronization. Additionally, background synaptic activity, in particular arising from NMDA receptors, has a large impact on the synchrony observed in the aforementioned circuit. Our results give new insights to the basic connection paradigms of microcircuits that lead to coordination and the formation of assemblies.
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Affiliation(s)
- Markus M Hilscher
- Neurodynamics Lab, Department of Neuroscience, Uppsala University Uppsala, Sweden ; Brain Institute, Federal University of Rio Grande do Norte Natal, Brazil
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Leão RN, Mikulovic S, Leão KE, Munguba H, Gezelius H, Enjin A, Patra K, Eriksson A, Loew LM, Tort ABL, Kullander K. OLM interneurons differentially modulate CA3 and entorhinal inputs to hippocampal CA1 neurons. Nat Neurosci 2012; 15:1524-30. [PMID: 23042082 PMCID: PMC3483451 DOI: 10.1038/nn.3235] [Citation(s) in RCA: 231] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 09/12/2012] [Indexed: 12/12/2022]
Abstract
The vast diversity of GABAergic interneurons is believed to endow hippocampal microcircuits with the required flexibility for memory encoding and retrieval. However, dissection of the functional roles of defined interneuron types have been hampered by the lack of cell specific tools. Here we report a precise molecular marker for a population of hippocampal GABAergic interneurons known as oriens lacunosum-moleculare (OLM) cells. By combining novel transgenic mice and optogenetic tools, we demonstrate that OLM cells have a key role in gating the information flow in CA1, facilitating the transmission of intrahippocampal information (from CA3) while reducing the influence of extrahippocampal inputs (from the entorhinal cortex). We further demonstrate that OLM cells are interconnected by gap junctions, receive direct cholinergic inputs from subcortical afferents, and account for the effect of nicotine on synaptic plasticity of the Schaffer collateral pathway. Our results suggest that acetylcholine acting through OLM cells can control the mnemonic processes executed by the hippocampus.
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Affiliation(s)
- Richardson N Leão
- Developmental Genetics, Department of Neuroscience, Uppsala University, Uppsala, Sweden
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20
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Leão RN, Colom LV, Borgius L, Kiehn O, Fisahn A. Medial septal dysfunction by Aβ-induced KCNQ channel-block in glutamatergic neurons. Neurobiol Aging 2012; 33:2046-61. [DOI: 10.1016/j.neurobiolaging.2011.07.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 07/18/2011] [Accepted: 07/20/2011] [Indexed: 11/30/2022]
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Leão KE, Leão RN, Walmsley B. Modulation of dendritic synaptic processing in the lateral superior olive by hyperpolarization-activated currents. Eur J Neurosci 2011; 33:1462-70. [PMID: 21366727 DOI: 10.1111/j.1460-9568.2011.07627.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have previously shown that mice lateral superior olive (LSO) neurons exhibit a large hyperpolarization-activated current (I(h) ), and that hyperpolarization-activated cyclic-nucleotide-gated type 1 channels are present in both the soma and dendrites of these cells. Here we show that the dendritic I(h) in LSO neurons modulates the integration of multiple synaptic inputs. We tested the LSO neuron's ability to integrate synaptic inputs by evoking excitatory post-synaptic potentials (EPSPs) in conjunction with brief depolarizing current pulses (to simulate a second excitatory input) at different time delays. We compared LSO neurons with the native I(h) present in both the soma and dendrites (control) with LSO neurons without I(h) (blocked with ZD7288) and with LSO neurons with I(h) only present peri-somatically (ZD7288+ computer-simulated I(h) using a dynamic clamp). LSO neurons without I(h) had a wider time window for firing in response to inputs with short time separations. Simulated somatic I(h) (dynamic clamp) could not reverse this effect. Blocking I(h) also increased the summation of EPSPs elicited at both proximal and distal dendritic regions, and dramatically altered the integration of EPSPs and inhibitory post-synaptic potentials. The addition of simulated peri-somatic I(h) could not abolish a ZD7288-induced increase of responsiveness to widely separated excitatory inputs. Using a compartmental LSO model, we show that dendritic I(h) can reduce EPSP integration by locally decreasing the input resistance. Our results suggest a significant role for dendritic I(h) in LSO neurons, where the activation/deactivation of I(h) can alter the LSO response to synaptic inputs.
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Affiliation(s)
- Katarina E Leão
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia.
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Couchman K, Garrett A, Deardorff AS, Rattay F, Resatz S, Fyffe R, Walmsley B, Leão RN. Lateral superior olive function in congenital deafness. Hear Res 2011; 277:163-75. [PMID: 21276842 DOI: 10.1016/j.heares.2011.01.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 01/14/2011] [Accepted: 01/19/2011] [Indexed: 10/18/2022]
Abstract
The development of cochlear implants for the treatment of patients with profound hearing loss has advanced considerably in the last few decades, particularly in the field of speech comprehension. However, attempts to provide not only sound decoding but also spatial hearing are limited by our understanding of circuit adaptations in the absence of auditory input. Here we investigate the lateral superior olive (LSO), a nucleus involved in interaural level difference (ILD) processing in the auditory brainstem using a mouse model of congenital deafness (the dn/dn mouse). An electrophysiological investigation of principal neurons of the LSO from the dn/dn mouse reveals a higher than normal proportion of single spiking (SS) neurons, and an increase in the hyperpolarisation-activated I(h) current. However, inhibitory glycinergic input to the LSO appears to develop normally both pre and postsynaptically in dn/dn mice despite the absence of auditory nerve activity. In combination with previous electrophysiological findings from the dn/dn mouse, we also compile a simple Hodgkin and Huxley circuit model in order to investigate possible computational deficits in ILD processing resulting from congenital hearing loss. We find that the predominance of SS neurons in the dn/dn LSO may compensate for upstream modifications and help to maintain a functioning ILD circuit in the dn/dn mouse. This could have clinical repercussions on the development of stimulation paradigms for spatial hearing with cochlear implants.
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Affiliation(s)
- Kiri Couchman
- Division of Neuroscience, The John Curtin School of Medical Research, Australian National University, Canberra ACT, Australia
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23
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Wicklund L, Leão RN, Strömberg AM, Mousavi M, Hovatta O, Nordberg A, Marutle A. Β-amyloid 1-42 oligomers impair function of human embryonic stem cell-derived forebrain cholinergic neurons. PLoS One 2010; 5:e15600. [PMID: 21179413 PMCID: PMC3003688 DOI: 10.1371/journal.pone.0015600] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 11/15/2010] [Indexed: 12/20/2022] Open
Abstract
Cognitive impairment in Alzheimer's disease (AD) patients is associated with a decline in the levels of growth factors, impairment of axonal transport and marked degeneration of basal forebrain cholinergic neurons (BFCNs). Neurogenesis persists in the adult human brain, and the stimulation of regenerative processes in the CNS is an attractive prospect for neuroreplacement therapy in neurodegenerative diseases such as AD. Currently, it is still not clear how the pathophysiological environment in the AD brain affects stem cell biology. Previous studies investigating the effects of the β-amyloid (Aβ) peptide on neurogenesis have been inconclusive, since both neurogenic and neurotoxic effects on progenitor cell populations have been reported. In this study, we treated pluripotent human embryonic stem (hES) cells with nerve growth factor (NGF) as well as with fibrillar and oligomeric Aβ1-40 and Aβ1-42 (nM-µM concentrations) and thereafter studied the differentiation in vitro during 28-35 days. The process applied real time quantitative PCR, immunocytochemistry as well as functional studies of intracellular calcium signaling. Treatment with NGF promoted the differentiation into functionally mature BFCNs. In comparison to untreated cells, oligomeric Aβ1-40 increased the number of functional neurons, whereas oligomeric Aβ1-42 suppressed the number of functional neurons. Interestingly, oligomeric Aβ exposure did not influence the number of hES cell-derived neurons compared with untreated cells, while in contrast fibrillar Aβ1-40 and Aβ1-42 induced gliogenesis. These findings indicate that Aβ1-42 oligomers may impair the function of stem cell-derived neurons. We propose that it may be possible for future AD therapies to promote the maturation of functional stem cell-derived neurons by altering the brain microenvironment with trophic support and by targeting different aggregation forms of Aβ.
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Affiliation(s)
- Linn Wicklund
- Department of Neurobiology, Care Sciences and Society, Division of Alzheimer Neurobiology, Karolinska Institutet, Stockholm, Sweden
| | - Richardson N. Leão
- Department of Neuroscience, Neuronal Oscillation Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Anne-Marie Strömberg
- Department of Clinical Science, Intervention and Technology, Division of Obstetrics and Gynecology, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Malahat Mousavi
- Department of Neurobiology, Care Sciences and Society, Division of Alzheimer Neurobiology, Karolinska Institutet, Stockholm, Sweden
| | - Outi Hovatta
- Department of Clinical Science, Intervention and Technology, Division of Obstetrics and Gynecology, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Agneta Nordberg
- Department of Neurobiology, Care Sciences and Society, Division of Alzheimer Neurobiology, Karolinska Institutet, Stockholm, Sweden
- Department of Geriatric Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Amelia Marutle
- Department of Neurobiology, Care Sciences and Society, Division of Alzheimer Neurobiology, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
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Leão RN, Reis A, Emirandetti A, Lewicka M, Hermanson O, Fisahn A. A voltage-sensitive dye-based assay for the identification of differentiated neurons derived from embryonic neural stem cell cultures. PLoS One 2010; 5:e13833. [PMID: 21079795 PMCID: PMC2973948 DOI: 10.1371/journal.pone.0013833] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 10/06/2010] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Pluripotent and multipotent stem cells hold great therapeutical promise for the replacement of degenerated tissue in neurological diseases. To fulfill that promise we have to understand the mechanisms underlying the differentiation of multipotent cells into specific types of neurons. Embryonic stem cell (ESC) and embryonic neural stem cell (NSC) cultures provide a valuable tool to study the processes of neural differentiation, which can be assessed using immunohistochemistry, gene expression, Ca(2+)-imaging or electrophysiology. However, indirect methods such as protein and gene analysis cannot provide direct evidence of neuronal functionality. In contrast, direct methods such as electrophysiological techniques are well suited to produce direct evidence of neural functionality but are limited to the study of a few cells on a culture plate. METHODOLOGY/PRINCIPAL FINDINGS In this study we describe a novel method for the detection of action potential-capable neurons differentiated from embryonic NSC cultures using fast voltage-sensitive dyes (VSD). We found that the use of extracellularly applied VSD resulted in a more detailed labeling of cellular processes compared to calcium indicators. In addition, VSD changes in fluorescence translated precisely to action potential kinetics as assessed by the injection of simulated slow and fast sodium currents using the dynamic clamp technique. We further demonstrate the use of a finite element model of the NSC culture cover slip for optimizing electrical stimulation parameters. CONCLUSIONS/SIGNIFICANCE Our method allows for a repeatable fast and accurate stimulation of neurons derived from stem cell cultures to assess their differentiation state, which is capable of monitoring large amounts of cells without harming the overall culture.
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Affiliation(s)
- Richardson N. Leão
- Neuronal Oscillations Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Amilcar Reis
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Amanda Emirandetti
- Developmental Genetics Group, Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Michalina Lewicka
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Ola Hermanson
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - André Fisahn
- Neuronal Oscillations Laboratory, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
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25
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Leão KE, Leão RN, Deardorff AS, Garrett A, Fyffe R, Walmsley B. Sound stimulation modulates high-threshold K(+) currents in mouse auditory brainstem neurons. Eur J Neurosci 2010; 32:1658-67. [PMID: 20946234 DOI: 10.1111/j.1460-9568.2010.07437.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The auditory system provides a valuable experimental model to investigate the role of sensory activity in regulating neuronal membrane properties. In this study, we have investigated the role of activity directly by measuring changes in medial nucleus of the trapezoid body (MNTB) neurons in normal hearing mice subjected to 1-h sound stimulation. Broadband (4-12 kHz) chirps were used to activate MNTB neurons tonotopically restricted to the lateral MNTB, as confirmed by c-Fos-immunoreactivity. Following 1-h sound stimulation a substantial increase in Kv3.1b-immunoreactivity was measured in the lateral region of the MNTB, which lasted for 2 h before returning to control levels. Electrophysiological patch-clamp recordings in brainstem slices revealed an increase in high-threshold potassium currents in the lateral MNTB of sound-stimulated mice. Current-clamp and dynamic-clamp experiments showed that MNTB cells from the sound-stimulated mice were able to maintain briefer action potentials during high-frequency firing than cells from control mice. These results provide evidence that acoustically driven auditory activity can selectively regulate high-threshold potassium currents in the MNTB of normal hearing mice, likely due to an increased membrane expression of Kv3.1b channels.
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Affiliation(s)
- Katarina E Leão
- The John Curtin School of Medical Research, Australian National University, Canberra ACT, Australia
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Leão RN, Leão RM, da Costa LF, Rock Levinson S, Walmsley B. A novel role for MNTB neuron dendrites in regulating action potential amplitude and cell excitability during repetitive firing. Eur J Neurosci 2008; 27:3095-108. [PMID: 18598256 DOI: 10.1111/j.1460-9568.2008.06297.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Principal cells of the medial nucleus of the trapezoid body (MNTB) are simple round neurons that receive a large excitatory synapse (the calyx of Held) and many small inhibitory synapses on the soma. Strangely, these neurons also possess one or two short tufted dendrites, whose function is unknown. Here we assess the role of these MNTB cell dendrites using patch-clamp recordings, imaging and immunohistochemistry techniques. Using outside-out patches and immunohistochemistry, we demonstrate the presence of dendritic Na+ channels. Current-clamp recordings show that tetrodotoxin applied onto dendrites impairs action potential (AP) firing. Using Na+ imaging, we show that the dendrite may serve to maintain AP amplitudes during high-frequency firing, as Na+ clearance indendritic compartments is faster than axonal compartments. Prolonged high-frequency firing can diminish Na+ gradients in the axon while the dendritic gradient remains closer to resting conditions; therefore, the dendrite can provide additional inward current during prolonged firing. Using electron microscopy, we demonstrate that there are small excitatory synaptic boutons on dendrites. Multi-compartment MNTB cell simulations show that, with an active dendrite, dendritic excitatory postsynaptic currents (EPSCs) elicit delayed APs compared with calyceal EPSCs. Together with high- and low-threshold voltage-gated K+ currents, we suggest that the function of the MNTB dendrite is to improve high-fidelity firing, and our modelling results indicate that an active dendrite could contribute to a 'dual' firing mode for MNTB cells (an instantaneous response to calyceal inputs and a delayed response to non-calyceal dendritic excitatory postsynaptic potentials).
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Affiliation(s)
- Richardson N Leão
- Synapse and Hearing Laboratory, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia.
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Abstract
Sodium currents are essential for action potential generation and propagation in most excitable cells. Appropriate tuning of these currents can be modulated both developmentally and in response to activity. Here we use a mouse model of congenital deafness (dn/dn- asymptomatic deafness associated with hair cell degeneration) to investigate the effect of lack of activity in the expression of Na(+) currents in neurons from the medial nucleus of the trapezoid body (MNTB). Patch-clamp recordings show that at postnatal day (P) 14, both normal and deaf mice display a significant amount of persistent and resurgent Na(+) currents. However, the persistent current is greater in deaf mice than in normal mice, and resurgent current kinetics are slower in deaf mice. At P7, resurgent currents are not present in either group. MNTB immunohistochemistry demonstrates that Nav1.1 subunits are expressed postsynaptically in both P14 normal and deaf mice, while postsynaptic Nav1.6 staining was only observed in deaf mice. Labelling of Nav1.6 subunits in different age groups revealed that at younger ages (P7), both normal and deaf mice express this protein. Nav1.6 staining was not observed in MNTB neurons of P28 normal mice, whereas it is maintained in deaf mice cells until much later (P28). At P7, none of the groups displayed resurgent currents (despite the detection of Nav1.6 subunits at this age group); this suggests that factors other than alpha subunits are important for modulating these currents in MNTB cells. Our results emphasize the importance of activity during development in regulating Na(+) channels.
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Affiliation(s)
- Richardson N Leão
- Synapse and Hearing Laboratory, Division of Neuroscience, John Curtin School of Medical Research, Australian National University, PO Box 334, Canberra, ACT 0200, Australia.
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