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Ripamonte GC, Fonseca EM, Frias AT, Patrone LGA, Vilela-Costa HH, Silva KSC, Szawka RE, Bícego KC, Zangrossi H, Plummer NW, Jensen P, Gargaglioni LH. Locus coeruleus noradrenaline depletion and its differential impact on CO 2-induced panic and hyperventilation in male and female mice. Prog Neuropsychopharmacol Biol Psychiatry 2024; 134:111063. [PMID: 38908504 DOI: 10.1016/j.pnpbp.2024.111063] [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: 11/06/2023] [Revised: 04/11/2024] [Accepted: 06/17/2024] [Indexed: 06/24/2024]
Abstract
CO2 exposure has been used to investigate the panicogenic response in patients with panic disorder. These patients are more sensitive to CO2, and more likely to experience the "false suffocation alarm" which triggers panic attacks. Imbalances in locus coeruleus noradrenergic (LC-NA) neurotransmission are responsible for psychiatric disorders, including panic disorder. These neurons are sensitive to changes in CO2/pH. Therefore, we investigated if LC-NA neurons are differentially activated after severe hypercapnia in mice. Further, we evaluated the participation of LC-NA neurons in ventilatory and panic-like escape responses induced by 20% CO2 in male and female wild type mice and two mouse models of altered LC-NA synthesis. Hypercapnia activates the LC-NA neurons, with males presenting a heightened level of activation. Mutant males lacking or with reduced LC-NA synthesis showed hypoventilation, while animals lacking LC noradrenaline present an increased metabolic rate compared to wild type in normocapnia. When exposed to CO2, males lacking LC noradrenaline showed a lower respiratory frequency compared to control animals. On the other hand, females lacking LC noradrenaline presented a higher tidal volume. Nevertheless, no change in ventilation was observed in either sex. CO2 evoked an active escape response. Mice lacking LC noradrenaline had a blunted jumping response and an increased freezing duration compared to the other groups. They also presented fewer racing episodes compared to wild type animals, but not different from mice with reduced LC noradrenaline. These findings suggest that LC-NA has an important role in ventilatory and panic-like escape responses elicited by CO2 exposure in mice.
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Affiliation(s)
- Gabriel C Ripamonte
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinarian Sciences, São Paulo State University, Jaboticabal, São Paulo, 14884-900, Brazil
| | - Elisa M Fonseca
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Alana T Frias
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinarian Sciences, São Paulo State University, Jaboticabal, São Paulo, 14884-900, Brazil
| | - Luis Gustavo A Patrone
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinarian Sciences, São Paulo State University, Jaboticabal, São Paulo, 14884-900, Brazil
| | - Heloísa H Vilela-Costa
- Department of Biochemistry, Pharmacology and Physiology, Institute of Biological and Natural Sciences, Federal University of Triangulo Mineiro, Uberaba, MG, Brazil
| | - Kaoma S C Silva
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais - UFMG, Belo Horizonte, MG, Brazil
| | - Raphael E Szawka
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais - UFMG, Belo Horizonte, MG, Brazil
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinarian Sciences, São Paulo State University, Jaboticabal, São Paulo, 14884-900, Brazil
| | - Hélio Zangrossi
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3900, Ribeirão Preto CEP:14049-900, Brazil
| | - Nicholas W Plummer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, United States Department of Health and Human Services, Durham, NC, USA
| | - Patricia Jensen
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, United States Department of Health and Human Services, Durham, NC, USA
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinarian Sciences, São Paulo State University, Jaboticabal, São Paulo, 14884-900, Brazil.
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2
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de Ávila C, Gugula A, Trenk A, Intorcia AJ, Suazo C, Nolz J, Plamondon J, Khatri D, Tallant L, Caron A, Blasiak A, Serrano GE, Beach TG, Gundlach AL, Mastroeni DF. Unveiling a novel memory center in human brain: neurochemical identification of the nucleus incertus, a key pontine locus implicated in stress and neuropathology. Biol Res 2024; 57:46. [PMID: 39014514 PMCID: PMC11253401 DOI: 10.1186/s40659-024-00523-z] [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: 10/13/2023] [Accepted: 06/07/2024] [Indexed: 07/18/2024] Open
Abstract
BACKGROUND The nucleus incertus (NI) was originally described by Streeter in 1903, as a midline region in the floor of the fourth ventricle of the human brain with an 'unknown' function. More than a century later, the neuroanatomy of the NI has been described in lower vertebrates, but not in humans. Therefore, we examined the neurochemical anatomy of the human NI using markers, including the neuropeptide, relaxin-3 (RLN3), and began to explore the distribution of the NI-related RLN3 innervation of the hippocampus. METHODS Histochemical staining of serial, coronal sections of control human postmortem pons was conducted to reveal the presence of the NI by detection of immunoreactivity (IR) for the neuronal markers, microtubule-associated protein-2 (MAP2), glutamic acid dehydrogenase (GAD)-65/67 and corticotrophin-releasing hormone receptor 1 (CRHR1), and RLN3, which is highly expressed in NI neurons in diverse species. RLN3 and vesicular GABA transporter 1 (vGAT1) mRNA were detected by fluorescent in situ hybridization. Pons sections containing the NI from an AD case were immunostained for phosphorylated-tau, to explore potential relevance to neurodegenerative diseases. Lastly, sections of the human hippocampus were stained to detect RLN3-IR and somatostatin (SST)-IR. RESULTS In the dorsal, anterior-medial region of the human pons, neurons containing RLN3- and MAP2-IR, and RLN3/vGAT1 mRNA-positive neurons were observed in an anatomical pattern consistent with that of the NI in other species. GAD65/67- and CRHR1-immunopositive neurons were also detected within this area. Furthermore, RLN3- and AT8-IR were co-localized within NI neurons of an AD subject. Lastly, RLN3-IR was detected in neurons within the CA1, CA2, CA3 and DG areas of the hippocampus, in the absence of RLN3 mRNA. In the DG, RLN3- and SST-IR were co-localized in a small population of neurons. CONCLUSIONS Aspects of the anatomy of the human NI are shared across species, including a population of stress-responsive, RLN3-expressing neurons and a RLN3 innervation of the hippocampus. Accumulation of phosphorylated-tau in the NI suggests its possible involvement in AD pathology. Further characterization of the neurochemistry of the human NI will increase our understanding of its functional role in health and disease.
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Affiliation(s)
- Camila de Ávila
- Arizona State University-Banner Neurodegenerative Disease Research Center, Tempe, AZ, USA.
| | - Anna Gugula
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Aleksandra Trenk
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Anthony J Intorcia
- Arizona Alzheimer's Consortium, Phoenix, AZ, USA
- Banner Sun Health Research Institute, Sun City, AZ, USA
| | - Crystal Suazo
- Arizona State University-Banner Neurodegenerative Disease Research Center, Tempe, AZ, USA
| | - Jennifer Nolz
- Arizona State University-Banner Neurodegenerative Disease Research Center, Tempe, AZ, USA
| | | | - Divyanshi Khatri
- Arizona State University-Banner Neurodegenerative Disease Research Center, Tempe, AZ, USA
| | - Lauren Tallant
- Department of Neuroscience, Mayo Clinic, Scottsdale, AZ, USA
| | - Alexandre Caron
- Quebec Heart and Lung Institute, Quebec City, QC, Canada
- Faculty of Pharmacy, Université Laval, Quebec City, QC, Canada
| | - Anna Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Geidy E Serrano
- Arizona Alzheimer's Consortium, Phoenix, AZ, USA
- Banner Sun Health Research Institute, Sun City, AZ, USA
| | - Thomas G Beach
- Arizona Alzheimer's Consortium, Phoenix, AZ, USA
- Banner Sun Health Research Institute, Sun City, AZ, USA
| | - Andrew L Gundlach
- Florey Department of Neuroscience and Mental Health and Department of Anatomy and Physiology and The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Diego F Mastroeni
- Arizona State University-Banner Neurodegenerative Disease Research Center, Tempe, AZ, USA
- Arizona Alzheimer's Consortium, Phoenix, AZ, USA
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3
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Lawson KA, Ruiz CM, Mahler SV. A head-to-head comparison of two DREADD agonists for suppressing operant behavior in rats via VTA dopamine neuron inhibition. Psychopharmacology (Berl) 2023; 240:2101-2110. [PMID: 37530882 PMCID: PMC10794001 DOI: 10.1007/s00213-023-06429-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 07/18/2023] [Indexed: 08/03/2023]
Abstract
RATIONALE Designer receptors exclusively activated by designer drugs (DREADDs) are a tool for "remote control" of defined neuronal populations during behavior. These receptors are inert unless bound by an experimenter-administered designer drug, commonly clozapine-n-oxide (CNO). However, questions have emerged about the suitability of CNO as a systemically administered DREADD agonist. OBJECTIVES Second-generation agonists such as JHU37160 (J60) have been developed, which may have more favorable properties than CNO. Here we sought to directly compare effects of CNO (0, 1, 5, & 10 mg/kg, i.p.) and J60 (0, 0.03, 0.3, & 3 mg/kg, i.p.) on operant food pursuit. METHODS Male and female TH:Cre + rats and their wildtype (WT) littermates received cre-dependent hM4Di-mCherry vector injections into ventral tegmental area (VTA), causing inhibitory DREADD expression in VTA dopamine neurons of TH:Cre + rats. All rats were trained to stably lever press for palatable food on a fixed ratio 10 schedule, and doses of both agonists were tested on separate days in counterbalanced order. RESULTS All three CNO doses reduced operant rewards earned in rats with DREADDs, and no CNO dose had behavioral effects in WT controls. The highest J60 dose tested significantly reduced responding in DREADD rats, but this dose also increased responding in WTs, indicating non-specific effects. The magnitude of CNO and J60 effects in TH:Cre + rats were correlated and were present in both sexes. CONCLUSIONS Findings demonstrate the usefulness of directly comparing DREADD agonists when optimizing behavioral chemogenetics, and highlight the importance of proper controls, regardless of the DREADD agonist employed.
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Affiliation(s)
- Kate A Lawson
- Department of Neurobiology and Behavior, University of California Irvine, 1132 McGaugh Hall, Irvine, CA, 92697, USA.
| | - Christina M Ruiz
- Department of Neurobiology and Behavior, University of California Irvine, 1132 McGaugh Hall, Irvine, CA, 92697, USA
| | - Stephen V Mahler
- Department of Neurobiology and Behavior, University of California Irvine, 1132 McGaugh Hall, Irvine, CA, 92697, USA
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4
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Lawson KA, Ruiz CM, Mahler SV. A head-to-head comparison of two DREADD agonists for suppressing operant behavior in rats via VTA dopamine neuron inhibition. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.27.534429. [PMID: 37034819 PMCID: PMC10081263 DOI: 10.1101/2023.03.27.534429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Rationale Designer receptors exclusively activated by designer drugs (DREADDs) are a tool for "remote control" of defined neuronal populations during behavior. These receptors are inert unless bound by an experimenter-administered designer drug, most commonly clozapine-n-oxide (CNO). However, questions have emerged about the suitability of CNO as a systemically administered DREADD agonist. Objectives Second-generation agonists such as JHU37160 (J60) have been developed, which may have more favorable properties than CNO. Here we sought to directly compare effects of CNO (0, 1, 5, & 10 mg/kg, i.p.) and J60 (0, 0.03, 0.3, & 3 mg/kg, i.p.) on operant food pursuit. Methods Male and female TH:Cre+ rats and their wildtype (WT) littermates received cre-dependent hM4Di-mCherry vector injections into ventral tegmental area (VTA), causing inhibitory DREADD expression in VTA dopamine neurons in TH:Cre+ rats. Rats were trained to stably lever press for palatable food on a fixed ratio 10 schedule, and doses of both agonists were tested on separate days in a counterbalanced order. Results All three CNO doses reduced operant food seeking in rats with DREADDs, and no CNO dose had behavioral effects in WT controls. The highest tested J60 dose significantly reduced responding in DREADD rats, but this dose also increased responding in WTs, indicating non-specific effects. The magnitude of CNO and J60 effects in TH:Cre+ rats were correlated and were present in both sexes. Conclusions Findings demonstrate the usefulness of directly comparing DREADD agonists when optimizing behavioral chemogenetics, and highlight the importance of proper controls, regardless of the DREADD agonist employed.
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Affiliation(s)
- Kate A Lawson
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA USA
| | - Christina M Ruiz
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA USA
| | - Stephen V Mahler
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA USA
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5
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McKinney A, Hu M, Hoskins A, Mohammadyar A, Naeem N, Jing J, Patel SS, Sheth BR, Jiang X. Cellular composition and circuit organization of the locus coeruleus of adult mice. eLife 2023; 12:e80100. [PMID: 36734517 PMCID: PMC9934863 DOI: 10.7554/elife.80100] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 02/01/2023] [Indexed: 02/04/2023] Open
Abstract
The locus coeruleus (LC) houses the vast majority of noradrenergic neurons in the brain and regulates many fundamental functions, including fight and flight response, attention control, and sleep/wake cycles. While efferent projections of the LC have been extensively investigated, little is known about its local circuit organization. Here, we performed large-scale multipatch recordings of noradrenergic neurons in adult mouse LC to profile their morpho-electric properties while simultaneously examining their interactions. LC noradrenergic neurons are diverse and could be classified into two major morpho-electric types. While fast excitatory synaptic transmission among LC noradrenergic neurons was not observed in our preparation, these mature LC neurons connected via gap junction at a rate similar to their early developmental stage and comparable to other brain regions. Most electrical connections form between dendrites and are restricted to narrowly spaced pairs or small clusters of neurons of the same type. In addition, more than two electrically coupled cell pairs were often identified across a cohort of neurons from individual multicell recording sets that followed a chain-like organizational pattern. The assembly of LC noradrenergic neurons thus follows a spatial and cell-type-specific wiring principle that may be imposed by a unique chain-like rule.
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Affiliation(s)
- Andrew McKinney
- Neuroscience Graduate Program, Baylor College of MedicineHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | - Ming Hu
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | | | | | | | - Junzhan Jing
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | - Saumil S Patel
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
| | - Bhavin R Sheth
- Department of Electrical and Computer Engineering, University of HoustonHoustonUnited States
- Center for NeuroEngineering and Cognitive Science, University of HoustonHoustonUnited States
| | - Xiaolong Jiang
- Neuroscience Graduate Program, Baylor College of MedicineHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Department of Ophthalmology, Baylor College of MedicineHoustonUnited States
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6
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Lorenzon N, Musoles-Lleó J, Turrisi F, Gomis-González M, De La Torre R, Dierssen M. State-of-the-art therapy for Down syndrome. Dev Med Child Neurol 2023. [PMID: 36692980 DOI: 10.1111/dmcn.15517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 12/04/2022] [Accepted: 12/19/2022] [Indexed: 01/25/2023]
Abstract
In the last decade, an important effort was made in the field of Down syndrome to find new interventions that improve cognition. These therapies have added to the traditional symptomatic treatments and to the drugs for treating Alzheimer disease in the general population repurposed for Down syndrome. Defining next-generation therapeutics will involve biomarker-based therapeutic decision-making, and preventive and multimodal interventions. However, translation of specific findings into effective therapeutic strategies has been disappointingly slow and has failed in many cases at the clinical level, leading to reduced credibility of mouse studies. This is aggravated by a tendency to favour large-magnitude effects and highly significant findings, leading to high expectations but also to a biased view of the complex pathophysiology of Down syndrome. Here, we review some of the most recent and promising strategies for ameliorating the cognitive state of individuals with Down syndrome. We studied the landscape of preclinical and clinical studies and conducted a thorough literature search on PubMed and ClinicalTrials.gov for articles published between June 2012 and August 2022 on therapies for ameliorating cognitive function in individuals with Down syndrome. We critically assess current therapeutic approaches, why therapies fail in clinical trials in Down syndrome, and what could be the path forward. We discuss some intrinsic difficulties for translational research, and the need for a framework that improves the detection of drug efficacy to avoid discarding compounds too early from the companies' pipelines.
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Affiliation(s)
- Nicola Lorenzon
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Juanluis Musoles-Lleó
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Federica Turrisi
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain.,Integrative Pharmacology and Systems Neurosciences Research Group, Neurosciences Research Program, Hospital del Mar Medical Research Institute, Barcelona, Spain
| | - Maria Gomis-González
- Integrative Pharmacology and Systems Neurosciences Research Group, Neurosciences Research Program, Hospital del Mar Medical Research Institute, Barcelona, Spain
| | - Rafael De La Torre
- Universitat Pompeu Fabra, Barcelona, Spain.,Integrative Pharmacology and Systems Neurosciences Research Group, Neurosciences Research Program, Hospital del Mar Medical Research Institute, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición, Instituto de Salud Carlos III, Madrid, Spain
| | - Mara Dierssen
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
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7
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Evans AK, Defensor E, Shamloo M. Selective Vulnerability of the Locus Coeruleus Noradrenergic System and its Role in Modulation of Neuroinflammation, Cognition, and Neurodegeneration. Front Pharmacol 2022; 13:1030609. [PMID: 36532725 PMCID: PMC9748190 DOI: 10.3389/fphar.2022.1030609] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 11/14/2022] [Indexed: 05/13/2024] Open
Abstract
Locus coeruleus (LC) noradrenergic (NE) neurons supply the main adrenergic input to the forebrain. NE is a dual modulator of cognition and neuroinflammation. NE neurons of the LC are particularly vulnerable to degeneration both with normal aging and in neurodegenerative disorders. Consequences of this vulnerability can be observed in both cognitive impairment and dysregulation of neuroinflammation. LC NE neurons are pacemaker neurons that are active during waking and arousal and are responsive to stressors in the environment. Chronic overactivation is thought to be a major contributor to the vulnerability of these neurons. Here we review what is known about the mechanisms underlying this neuronal vulnerability and combinations of environmental and genetic factors that contribute to confer risk to these important brainstem neuromodulatory and immunomodulatory neurons. Finally, we discuss proposed and potential interventions that may reduce the overall risk for LC NE neuronal degeneration.
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Affiliation(s)
- Andrew K. Evans
- School of Medicine, Stanford University, Stanford, CA, United States
| | | | - Mehrdad Shamloo
- School of Medicine, Stanford University, Stanford, CA, United States
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8
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Chao OY, Nikolaus S, Yang YM, Huston JP. Neuronal circuitry for recognition memory of object and place in rodent models. Neurosci Biobehav Rev 2022; 141:104855. [PMID: 36089106 PMCID: PMC10542956 DOI: 10.1016/j.neubiorev.2022.104855] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 08/23/2022] [Accepted: 08/30/2022] [Indexed: 10/14/2022]
Abstract
Rats and mice are used for studying neuronal circuits underlying recognition memory due to their ability to spontaneously remember the occurrence of an object, its place and an association of the object and place in a particular environment. A joint employment of lesions, pharmacological interventions, optogenetics and chemogenetics is constantly expanding our knowledge of the neural basis for recognition memory of object, place, and their association. In this review, we summarize current studies on recognition memory in rodents with a focus on the novel object preference, novel location preference and object-in-place paradigms. The evidence suggests that the medial prefrontal cortex- and hippocampus-connected circuits contribute to recognition memory for object and place. Under certain conditions, the striatum, medial septum, amygdala, locus coeruleus and cerebellum are also involved. We propose that the neuronal circuitry for recognition memory of object and place is hierarchically connected and constructed by different cortical (perirhinal, entorhinal and retrosplenial cortices), thalamic (nucleus reuniens, mediodorsal and anterior thalamic nuclei) and primeval (hypothalamus and interpeduncular nucleus) modules interacting with the medial prefrontal cortex and hippocampus.
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Affiliation(s)
- Owen Y Chao
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN 55812, USA
| | - Susanne Nikolaus
- Department of Nuclear Medicine, University Hospital Düsseldorf, Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Yi-Mei Yang
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN 55812, USA; Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Joseph P Huston
- Center for Behavioral Neuroscience, Institute of Experimental Psychology, Heinrich-Heine University, 40225 Düsseldorf, Germany.
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9
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Eriksson H, Rössler OG, Thiel G. Tyrosine hydroxylase gene promoter activity is upregulated in female catecholaminergic neuroblastoma cells following activation of a Gαq-coupled designer receptor. Neurochem Int 2022; 160:105407. [PMID: 35995267 DOI: 10.1016/j.neuint.2022.105407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 07/25/2022] [Accepted: 08/15/2022] [Indexed: 10/31/2022]
Abstract
Tyrosine hydroxylase is the rate-limiting enzyme of catecholamine biosynthesis that catalyzes the conversion of L-tyrosine to L-3,4-dihydroxyphenylalanine. The tyrosine hydroxylase gene is regulated by extracellular signaling molecules such as epidermal growth factor, nerve growth factor and steroids. Here, we investigated whether the activity of the tyrosine hydroxylase gene promoter is upregulated by activation of G protein-coupled receptors, the largest group of plasma membrane receptors. We used catecholaminergic neuroblastoma cells as a cellular model and chromatin-integrated tyrosine hydroxylase promoter-luciferase reporter genes. The results show that stimulation of Rαq, a Gαq-coupled designer receptor, triggered transcription of a reporter gene driven by the tyrosine hydroxylase promoter. Transcription was attenuated by overexpression of regulator of G-protein signaling-2, which activates the GTPase activity of the G protein α-subunit, and by a truncated, dominant-negative mutant of phospholipase Cβ3. Extracellular signal-regulated protein kinase was identified as the signal transducer. At the transcriptional level, tyrosine hydroxylase promoter activity was found to be controlled by the transcription factor CREB. Expression experiments with the adenoviral regulator protein E1A, an inhibitor of CBP/p300 histone acetyltransferases, showed that transcription of the reporter gene controlled by the tyrosine hydroxylase is under epigenetic control. We identified the protein phosphatases MAP kinase phosphatase-1 and calcineurin as part of a shutdown device of the signaling cascade linking Rαq designer receptor activation to tyrosine hydroxylase gene transcription. We conclude that tyrosine hydroxylase promoter activity is controlled by Gαq-coupled receptors.
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Affiliation(s)
- Helen Eriksson
- Department of Medical Biochemistry and Molecular Biology, Saarland University Medical Faculty, D-66421, Homburg, Germany
| | - Oliver G Rössler
- Department of Medical Biochemistry and Molecular Biology, Saarland University Medical Faculty, D-66421, Homburg, Germany
| | - Gerald Thiel
- Department of Medical Biochemistry and Molecular Biology, Saarland University Medical Faculty, D-66421, Homburg, Germany.
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10
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Hawley LE, Prochaska F, Stringer M, Goodlett CR, Roper RJ. Sexually dimorphic DYRK1A overexpression on postnatal day 15 in the Ts65Dn mouse model of Down syndrome: Effects of pharmacological targeting on behavioral phenotypes. Pharmacol Biochem Behav 2022; 217:173404. [DOI: 10.1016/j.pbb.2022.173404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/09/2022] [Accepted: 05/10/2022] [Indexed: 10/18/2022]
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11
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Chemogenetics as a neuromodulatory approach to treating neuropsychiatric diseases and disorders. Mol Ther 2022; 30:990-1005. [PMID: 34861415 PMCID: PMC8899595 DOI: 10.1016/j.ymthe.2021.11.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 11/12/2021] [Accepted: 11/29/2021] [Indexed: 01/01/2023] Open
Abstract
Chemogenetics enables precise, non-invasive, and reversible modulation of neural activity via the activation of engineered receptors that are pharmacologically selective to endogenous or exogenous ligands. With recent advances in therapeutic gene delivery, chemogenetics is poised to support novel interventions against neuropsychiatric diseases and disorders. To evaluate its translational potential, we performed a scoping review of applications of chemogenetics that led to the reversal of molecular and behavioral deficits in studies relevant to neuropsychiatric diseases and disorders. In this review, we present these findings and discuss the potential and challenges for using chemogenetics as a precision medicine-based neuromodulation strategy.
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12
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Korczeniewska OA, James MH, Eliav T, Katzmann Rider G, Mehr JB, Affendi H, Aston-Jones G, Benoliel R. Chemogenetic inhibition of trigeminal ganglion neurons attenuates behavioural and neural pain responses in a model of trigeminal neuropathic pain. Eur J Pain 2021; 26:634-647. [PMID: 34767278 DOI: 10.1002/ejp.1887] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Nerve injury can lead to ectopic activation of injured nociceptorsand central sensitization characterized by allodynia and hyperalgesia. Reduction in the activity of primary afferent neurons has been shown to be sufficient in alleviating peripherally generated pain. The cell bodies of such trigeminal nociceptors are located in the trigeminal ganglia (TG) with central processes that terminate in the brainstem trigeminal nucleus caudalis (TNC). The TG is therefore a strategic locus where afferent input can be manipulated. We hypothesized that chemogenetic inhibition of TG would suppress TNC neuronal activity and attenuate pain behaviour in a rat model of painful traumatic trigeminal neuropathy (PTTN). METHODS Trigeminal neuropathic pain was induced in adult male Sprague-Dawley rats (n = 24) via chronic constriction injury to the infraorbital nerve (ION-CCI). Naïve and sham rats were used as controls (n = 20/group). Rats within each group received TG-directed microinjections of AAV virus containing either the inhibitory hM4Di-DREADD construct or EGFP. RESULTS In the ION-CCI group, systemic administration of the DREADD agonist clozapine N-oxide (CNO) reversed the hypersensitivity phenotype in animals expressing hM4Di but not EGFP. CNO-mediated activation of hM4Di DREADD in ION-CCI animals was also associated with reduced Fos expression in the TNC elicited by repeated mechanical stimulation of the dermatome ipsilateral to the injury. There was no effect of CNO on pain behaviour or TNC Fos expression in eGFP animals. CONCLUSION Our results indicate that DREADDs may offer an effective therapeutic approach for treatment of trigeminal neuropathic pain. SIGNIFICANCE Trigeminal neuropathic pain is highly resistant to therapy and we are in dire need of novel approaches. This study provides further evidence for the successful application of DREADDs as an effective tool for modulating central nervous system function. CNO mediated activation of hM4Di-DREADDs in the trigeminal ganglion (TG) attenuates nerve injury induced neuropathic pain by acting on hyperactive TG cells. It also establishes the TG as an effective target to manage pain in the face and head. Accessing the TG in clinical populations is a relatively simple and safe procedure, making this approach highly significant. Moreover, the methodology described here has applications in trigeminal neuropathic pain from traumatic other etiologies and in spinal neuropathic pain. Chronic pain syndromes are characterized by a progressive failure of brain centers to adequately inhibit pain and as these are identified, we may be able to target them for therapy. Therefore, our findings might have wide application in chronic pain syndromes.
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Affiliation(s)
- Olga A Korczeniewska
- Center for Orofacial Pain and Temporomandibular Disorders, Department of Diagnostic Sciences, Rutgers School of Dental Medicine, Rutgers University, Newark, New Jersey, USA.,Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
| | - Morgan H James
- Department of Psychiatry, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA.,Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
| | - Tali Eliav
- School of Graduate Studies, Rutgers Biomedical and Health Sciences, Newark, New Jersey, USA
| | - Giannina Katzmann Rider
- Center for Orofacial Pain and Temporomandibular Disorders, Department of Diagnostic Sciences, Rutgers School of Dental Medicine, Rutgers University, Newark, New Jersey, USA
| | - Jacqueline B Mehr
- Department of Psychiatry, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA.,Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
| | - Hafsa Affendi
- Center for Orofacial Pain and Temporomandibular Disorders, Department of Diagnostic Sciences, Rutgers School of Dental Medicine, Rutgers University, Newark, New Jersey, USA
| | - Gary Aston-Jones
- Department of Psychiatry, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA.,Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
| | - Rafael Benoliel
- Center for Orofacial Pain and Temporomandibular Disorders, Department of Diagnostic Sciences, Rutgers School of Dental Medicine, Rutgers University, Newark, New Jersey, USA.,Brain Health Institute, Rutgers University, Piscataway, New Jersey, USA
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13
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Holland N, Robbins TW, Rowe JB. The role of noradrenaline in cognition and cognitive disorders. Brain 2021; 144:2243-2256. [PMID: 33725122 PMCID: PMC8418349 DOI: 10.1093/brain/awab111] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 01/08/2021] [Accepted: 01/23/2021] [Indexed: 01/09/2023] Open
Abstract
Many aspects of cognition and behaviour are regulated by noradrenergic projections to the forebrain originating from the locus coeruleus, acting through alpha and beta adrenoreceptors. Loss of these projections is common in neurodegenerative diseases and contributes to their cognitive and behavioural deficits. We review the evidence for a noradrenergic modulation of cognition in its contribution to Alzheimer's disease, Parkinson's disease and other cognitive disorders. We discuss the advances in human imaging and computational methods that quantify the locus coeruleus and its function in humans, and highlight the potential for new noradrenergic treatment strategies.
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Affiliation(s)
- Negin Holland
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0SZ, UK
| | - Trevor W Robbins
- Department of Psychology, University of Cambridge, Cambridge CB2 3EB, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, UK
| | - James B Rowe
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0SZ, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, UK
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge CB2 7EF, UK
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14
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Gao FJ, Klinedinst D, Fernandez FX, Cheng B, Savonenko A, Devenney B, Li Y, Wu D, Pomper MG, Reeves RH. Forebrain Shh overexpression improves cognitive function and locomotor hyperactivity in an aneuploid mouse model of Down syndrome and its euploid littermates. Acta Neuropathol Commun 2021; 9:137. [PMID: 34399854 PMCID: PMC8365939 DOI: 10.1186/s40478-021-01237-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 08/01/2021] [Indexed: 11/10/2022] Open
Abstract
Down syndrome (DS) is the leading genetic cause of intellectual disability and causes early-onset dementia and cerebellar hypoplasia. The prevalence of attention deficit hyperactivity disorder is elevated in children with DS. The aneuploid DS mouse model "Ts65Dn" shows prominent brain phenotypes, including learning and memory deficits, cerebellar hypoplasia, and locomotor hyperactivity. Previous studies indicate that impaired Sonic hedgehog (Shh) signaling contributes to neurological phenotypes associated with DS and neurodegenerative diseases. However, because of a lack of working inducible Shh knock-in mice, brain region-specific Shh overexpression and its effects on cognitive function have not been studied in vivo. Here, with Gli1-LacZ reporter mice, we demonstrated that Ts65Dn had reduced levels of Gli1, a sensitive readout of Shh signaling, in both hippocampus and cerebellum at postnatal day 6. Through site-specific transgenesis, we generated an inducible human Shh knock-in mouse, TRE-bi-hShh-Zsgreen1 (TRE-hShh), simultaneously expressing dually-lipidated Shh-Np and Zsgreen1 marker in the presence of transactivator (tTA). Double transgenic mice "Camk2a-tTA;TRE-hShh" and "Pcp2-tTA;TRE-hShh" induced Shh overexpression and activated Shh signaling in a forebrain and cerebellum, respectively, specific manner from the perinatal period. Camk2a-tTA;TRE-hShh normalized locomotor hyperactivity and improved learning and memory in 3-month-old Ts65Dn, mitigated early-onset severe cognitive impairment in 7-month-old Ts65Dn, and enhanced spatial cognition in euploid mice. Camk2a-tTA;TRE-hShh cohort maintained until 600days old showed that chronic overexpression of Shh in forebrain from the perinatal period had no effect on longevity of euploid or Ts65Dn. Pcp2-tTA;TRE-hShh did not affect cognition but mitigated the phenotype of cerebellar hypoplasia in Ts65Dn. Our study provides the first in vivo evidence that Shh overexpression from the perinatal period protects DS brain integrity and enhances learning and memory in normal mice, indicating the broad therapeutic potential of Shh ligand for other neurological conditions. Moreover, the first inducible hShh site-specific knock-in mouse could be widely used for spatiotemporal Shh signaling regulation.
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Affiliation(s)
- Feng J Gao
- Department of Physiology, Johns Hopkins University, Baltimore, MD, 21205, USA.
- Department of Genetic Medicine, John Hopkins University, Baltimore, MD, 21205, USA.
| | - Donna Klinedinst
- Department of Physiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Fabian-Xosé Fernandez
- Department of Psychology, University of Arizona, Tucson, AZ, USA
- Department of Neurology, University of Arizona, Tucson, AZ, USA
- BIO5 and McKnight Brain Research Institutes, Tucson, AZ, USA
| | - Bei Cheng
- Department of Radiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Alena Savonenko
- Department of Pathology and Neurology, John Hopkins University, Baltimore, MD, 21205, USA
| | - Benjamin Devenney
- Department of Physiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Yicong Li
- Department of Physiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Dan Wu
- Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Martin G Pomper
- Department of Radiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Roger H Reeves
- Department of Physiology, Johns Hopkins University, Baltimore, MD, 21205, USA.
- Department of Genetic Medicine, John Hopkins University, Baltimore, MD, 21205, USA.
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15
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Pickering CA, Mazarakis ND. Viral Vector Delivery of DREADDs for CNS Therapy. Curr Gene Ther 2021; 21:191-206. [PMID: 33573551 DOI: 10.2174/1566523221666210211102435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/15/2021] [Accepted: 01/25/2021] [Indexed: 11/22/2022]
Abstract
Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) are genetically modified G-protein-coupled receptors (GPCRs), that can be activated by a synthetic ligand which is otherwise inert at endogenous receptors. DREADDs can be expressed in cells in the central nervous system (CNS) and subsequently offer the opportunity for remote and reversible silencing or activation of the target cells when the synthetic ligand is systemically administered. In neuroscience, DREADDs have thus far shown to be useful tools for several areas of research and offer considerable potential for the development of gene therapy strategies for neurological disorders. However, in order to design a DREADD-based gene therapy, it is necessary to first evaluate the viral vector delivery methods utilised in the literature to deliver these chemogenetic tools. This review evaluates each of the prominent strategies currently utilised for DREADD delivery, discussing their respective advantages and limitations. We focus on adeno-associated virus (AAV)-based and lentivirus-based systems, and the manipulation of these through cell-type specific promoters and pseudotyping. Furthermore, we address how virally mediated DREADD delivery could be improved in order to make it a viable gene therapy strategy and thus expand its translational potential.
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Affiliation(s)
- Ceri A Pickering
- Division of Neuroscience, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Nicholas D Mazarakis
- Division of Neuroscience, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
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16
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Delayed motor learning in a 16p11.2 deletion mouse model of autism is rescued by locus coeruleus activation. Nat Neurosci 2021; 24:646-657. [PMID: 33753944 DOI: 10.1038/s41593-021-00815-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 02/05/2021] [Indexed: 01/30/2023]
Abstract
Children with autism spectrum disorder often exhibit delays in achieving motor developmental milestones such as crawling, walking and speech articulation. However, little is known about the neural mechanisms underlying motor-related deficits. Here, we reveal that mice with a syntenic deletion of the chromosome 16p11.2, a common copy number variation associated with autism spectrum disorder, also exhibit delayed motor learning without showing gross motor deficits. Using in vivo two-photon imaging in awake mice, we find that layer 2/3 excitatory neurons in the motor cortex of adult male 16p11.2-deletion mice show abnormally high activity during the initial phase of learning, and the process of learning-induced spine reorganization is prolonged. Pharmacogenetic activation of locus coeruleus noradrenergic neurons was sufficient to rescue the circuit deficits and the delayed motor learning in these mice. Our results unveil an unanticipated role of noradrenergic neuromodulation in improving the delayed motor learning in 16p11.2-deletion male mice.
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17
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Stevens L, Larsen LE, Van Lysebettens W, Carrette E, Boon P, Raedt R, Vonck K. Optimized Parameters for Transducing the Locus Coeruleus Using Canine Adenovirus Type 2 (CAV2) Vector in Rats for Chemogenetic Modulation Research. Front Neurosci 2021; 15:663337. [PMID: 33927593 PMCID: PMC8076532 DOI: 10.3389/fnins.2021.663337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 03/24/2021] [Indexed: 12/26/2022] Open
Abstract
Introduction The locus coeruleus noradrenergic (LC-NA) system is studied for its role in various neurological and psychiatric disorders such as epilepsy and Major Depression Dissorder. Chemogenetics is a powerful technique for specific manipulation of the LC to investigate its functioning. Local injection of AAV2/7 viral vectors has limitations with regards to efficiency and specificity of the transduction, potentially due to low tropism of AAV2/7 for LC neurons. In this study we used a canine adenovirus type 2 (CAV2) vector with different volumes and viral particle numbers to achieve high and selective expression of hM3Dq, an excitatory Designer Receptor Exclusively Activated by Designer Drugs (DREADD), for chemogenetic modulation of LC neurons. Methods Adult male Sprague-Dawley rats were injected in the LC with different absolute numbers of CAV2-PRSx8-hM3Dq-mCherry physical particles (0.1E9, 1E9, 5E9,10E9, or 20E9 pp) using different volumes (LowV = 3 nl × 300 nl, MediumV = 3 × 600 nl, HighV = 3 × 1200 nl). Two weeks post-injection, double-labeling immunohistochemistry for dopamine β hydroxylase (DBH) and mCherry was performed to determine hM3Dq expression and its specificity for LC neurons. The size of the transduced LC was compared to the contralateral LC to identify signs of toxicity. Results Administration of Medium volume (3 × 600 nl) and 1E9 particles resulted in high expression levels with 87.3 ± 9.8% of LC neurons expressing hM3Dq, but low specificity with 36.2 ± 17.3% of hM3Dq expression in non-LC neurons. The most diluted conditions (Low volume_0.1E pp and Medium Volume_0.1E pp) presented similar high transduction of LC neurons (70.9 ± 12.7 and 77.2 ± 9.8%) with lower aspecificity (5.5 ± 3.5 and 4.0 ± 1.9%, respectively). Signs of toxicity were observed in all undiluted conditions as evidenced by a decreased size of the transduced LC. Conclusion This study identified optimal conditions (Low and Medium Volume with 0.1E9 particles of CAV2-PRSx8-hM3Dq-mCherry) for safe and specific transduction of LC neurons with excitatory DREADDs to study the role of the LC-NA system in health and disease.
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Affiliation(s)
- Latoya Stevens
- 4BRAIN, Institute for Neuroscience, Department Head and Skin, Ghent University, Ghent, Belgium
| | - Lars Emil Larsen
- 4BRAIN, Institute for Neuroscience, Department Head and Skin, Ghent University, Ghent, Belgium.,Medical Imaging and Signal Processing, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium
| | - Wouter Van Lysebettens
- 4BRAIN, Institute for Neuroscience, Department Head and Skin, Ghent University, Ghent, Belgium
| | - Evelien Carrette
- 4BRAIN, Institute for Neuroscience, Department Head and Skin, Ghent University, Ghent, Belgium
| | - Paul Boon
- 4BRAIN, Institute for Neuroscience, Department Head and Skin, Ghent University, Ghent, Belgium
| | - Robrecht Raedt
- 4BRAIN, Institute for Neuroscience, Department Head and Skin, Ghent University, Ghent, Belgium
| | - Kristl Vonck
- 4BRAIN, Institute for Neuroscience, Department Head and Skin, Ghent University, Ghent, Belgium
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18
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Dyavanapalli J. Novel approaches to restore parasympathetic activity to the heart in cardiorespiratory diseases. Am J Physiol Heart Circ Physiol 2020; 319:H1153-H1161. [PMID: 33035444 DOI: 10.1152/ajpheart.00398.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Neural control of the heart is regulated by sympathetic and parasympathetic divisions of the autonomic nervous system, both opposing each other to maintain cardiac homeostasis via regulating heart rate, conduction velocity, force of contraction, and coronary blood flow. Sympathetic hyperactivity and diminished parasympathetic activity are the characteristic features of many cardiovascular disease states including hypertension, myocardial ischemia, and arrhythmias that result in heart failure. Restoring parasympathetic activity to the heart has recently been identified as the promising approach to treat such conditions. However, approaches that used vagal nerve stimulation have been shown to be unsuccessful in heart failure. This review focuses on novel chemogenetic approaches used to identify the cardioprotective nature of activating neural points along the vagal pathway (both central and peripheral) while being selectively therapeutic in heart failure and obstructive sleep apnea.
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Affiliation(s)
- Jhansi Dyavanapalli
- Department of Pharmacology and Physiology, George Washington University, Washington, District of Columbia
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19
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López-Ferreras L, Eerola K, Shevchouk OT, Richard JE, Nilsson FH, Jansson LE, Hayes MR, Skibicka KP. The supramammillary nucleus controls anxiety-like behavior; key role of GLP-1R. Psychoneuroendocrinology 2020; 119:104720. [PMID: 32563174 DOI: 10.1016/j.psyneuen.2020.104720] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/30/2020] [Accepted: 05/18/2020] [Indexed: 01/04/2023]
Abstract
Anxiety disorders are among the most prevalent categories of mental illnesses. The gut-brain axis, along with gastrointestinally-derived neuropeptides, like glucagon-like peptide-1 (GLP-1), are emerging as potential key regulators of emotionality, including anxiety behavior. However, the neuroanatomical substrates from which GLP-1 exerts its anxiogenic effect remain poorly characterized. Here we focus on a relatively new candidate nucleus, the supramammillary nucleus (SuM), located just caudal to the lateral hypothalamus and ventral to the ventral tegmental area. Our focus on the SuM is supported by previous data showing expression of GLP-1R mRNA throughout the SuM and activation of the SuM during anxiety-inducing behaviors in rodents. Data show that chemogenetic activation of neurons in the SuM results in an anxiolytic response in male and female rats. In contrast, selective activation of SuM GLP-1R, by microinjection of a GLP-1R agonist exendin-4 into the SuM resulted in potent anxiety-like behavior, measured in both open field and elevated plus maze tests in male and female rats. This anxiogenic effect of GLP-1R activation persisted after high-fat diet exposure. Importantly, reduction of GLP-1R expression in the SuM, by AAV-shRNA GLP-1R knockdown, resulted in a clear anxiolytic response; an effect only observed in female rats. Our data identify a new neural substrate for GLP-1 control of anxiety-like behavior and indicate that the SuM GLP-1R are sufficient for anxiogenesis in both sexes, but necessary only in females.
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Affiliation(s)
- L López-Ferreras
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden; Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Sweden
| | - K Eerola
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden; Research Centre of Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Finland
| | - O T Shevchouk
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | - J E Richard
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | - F H Nilsson
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | - L E Jansson
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | - M R Hayes
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, USA
| | - K P Skibicka
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden; Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Sweden; Department of Nutritional Sciences, Pennsylvania State University, University Park, PA, USA.
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20
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Giorgi FS, Galgani A, Puglisi-Allegra S, Limanaqi F, Busceti CL, Fornai F. Locus Coeruleus and neurovascular unit: From its role in physiology to its potential role in Alzheimer's disease pathogenesis. J Neurosci Res 2020; 98:2406-2434. [PMID: 32875628 DOI: 10.1002/jnr.24718] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/26/2020] [Accepted: 08/08/2020] [Indexed: 12/15/2022]
Abstract
Locus coeruleus (LC) is the main noradrenergic (NA) nucleus of the central nervous system. LC degenerates early during Alzheimer's disease (AD) and NA loss might concur to AD pathogenesis. Aside from neurons, LC terminals provide dense innervation of brain intraparenchymal arterioles/capillaries, and NA modulates astrocyte functions. The term neurovascular unit (NVU) defines the strict anatomical/functional interaction occurring between neurons, glial cells, and brain vessels. NVU plays a fundamental role in coupling the energy demand of activated brain regions with regional cerebral blood flow, it includes the blood-brain barrier (BBB), plays an active role in neuroinflammation, and participates also to the glymphatic system. NVU alteration is involved in AD pathophysiology through several mechanisms, mainly related to a relative oligoemia in activated brain regions and impairment of structural and functional BBB integrity, which contributes also to the intracerebral accumulation of insoluble amyloid. We review the existing data on the morphological features of LC-NA innervation of the NVU, as well as its contribution to neurovascular coupling and BBB proper functioning. After introducing the main experimental data linking LC with AD, which have repeatedly shown a key role of neuroinflammation and increased amyloid plaque formation, we discuss the potential mechanisms by which the loss of NVU modulation by LC might contribute to AD pathogenesis. Surprisingly, thus far not so many studies have tested directly these mechanisms in models of AD in which LC has been lesioned experimentally. Clarifying the interaction of LC with NVU in AD pathogenesis may disclose potential therapeutic targets for AD.
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Affiliation(s)
- Filippo Sean Giorgi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.,Neurology Unit, Pisa University Hospital, Pisa, Italy
| | | | | | - Fiona Limanaqi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | | | - Francesco Fornai
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.,I.R.C.C.S. I.N.M. Neuromed, Pozzilli, Italy
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21
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Privitera M, Ferrari KD, von Ziegler LM, Sturman O, Duss SN, Floriou-Servou A, Germain PL, Vermeiren Y, Wyss MT, De Deyn PP, Weber B, Bohacek J. A complete pupillometry toolbox for real-time monitoring of locus coeruleus activity in rodents. Nat Protoc 2020; 15:2301-2320. [PMID: 32632319 DOI: 10.1038/s41596-020-0324-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 04/01/2020] [Indexed: 01/20/2023]
Abstract
The locus coeruleus (LC) is a region in the brainstem that produces noradrenaline and is involved in both normal and pathological brain function. Pupillometry, the measurement of pupil diameter, provides a powerful readout of LC activity in rodents, primates and humans. The protocol detailed here describes a miniaturized setup that can screen LC activity in rodents in real-time and can be established within 1-2 d. Using low-cost Raspberry Pi computers and cameras, the complete custom-built system costs only ~300 euros, is compatible with stereotaxic surgery frames and seamlessly integrates into complex experimental setups. Tools for pupil tracking and a user-friendly Pupillometry App allow quantification, analysis and visualization of pupil size. Pupillometry can discriminate between different, physiologically relevant firing patterns of the LC and can accurately report LC activation as measured by noradrenaline turnover. Pupillometry provides a rapid, non-invasive readout that can be used to verify accurate placement of electrodes/fibers in vivo, thus allowing decisions about the inclusion/exclusion of individual animals before experiments begin.
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Affiliation(s)
- Mattia Privitera
- Laboratory of Molecular and Behavioral Neuroscience, Institute for Neuroscience, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Kim David Ferrari
- Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland.,Experimental Imaging and Neuroenergetics, Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Lukas M von Ziegler
- Laboratory of Molecular and Behavioral Neuroscience, Institute for Neuroscience, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Oliver Sturman
- Laboratory of Molecular and Behavioral Neuroscience, Institute for Neuroscience, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Sian N Duss
- Laboratory of Molecular and Behavioral Neuroscience, Institute for Neuroscience, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Amalia Floriou-Servou
- Laboratory of Molecular and Behavioral Neuroscience, Institute for Neuroscience, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Pierre-Luc Germain
- Laboratory of Molecular and Behavioral Neuroscience, Institute for Neuroscience, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Yannick Vermeiren
- Department of Biomedical Sciences, Laboratory of Neurochemistry and Behavior, Institute Born-Bunge, University of Antwerp, Wilrijk (Antwerp), Antwerpen, Belgium.,Department of Neurology and Alzheimer Center, University of Groningen and University Medical Center Groningen (UMCG), Groningen, the Netherlands
| | - Matthias T Wyss
- Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland.,Experimental Imaging and Neuroenergetics, Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Peter P De Deyn
- Department of Biomedical Sciences, Laboratory of Neurochemistry and Behavior, Institute Born-Bunge, University of Antwerp, Wilrijk (Antwerp), Antwerpen, Belgium.,Department of Neurology and Alzheimer Center, University of Groningen and University Medical Center Groningen (UMCG), Groningen, the Netherlands.,Department of Neurology, Memory Clinic of Hospital Network Antwerp (ZNA) Middelheim and Hoge Beuken, Antwerp, Belgium
| | - Bruno Weber
- Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland. .,Experimental Imaging and Neuroenergetics, Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.
| | - Johannes Bohacek
- Laboratory of Molecular and Behavioral Neuroscience, Institute for Neuroscience, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland. .,Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland.
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22
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Stevens L, Vonck K, Larsen LE, Van Lysebettens W, Germonpré C, Baekelandt V, Van den Haute C, Carrette E, Wadman WJ, Boon P, Raedt R. A Feasibility Study to Investigate Chemogenetic Modulation of the Locus Coeruleus by Means of Single Unit Activity. Front Neurosci 2020; 14:162. [PMID: 32210746 PMCID: PMC7067893 DOI: 10.3389/fnins.2020.00162] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 02/12/2020] [Indexed: 11/13/2022] Open
Abstract
Aim Selective chemogenetic modulation of locus coeruleus (LC) neurons would allow dedicated investigation of the role of the LC-NA pathway in brain excitability and disorders such as epilepsy. This study investigated the feasibility of an experimental set-up where chemogenetic modification of the brainstem locus coeruleus NA neurons is aimed at and followed by LC unit activity recording in response to clozapine. Methods The LC of male Sprague-Dawley rats was injected with 10 nl of adeno-associated viral vector AAV2/7-PRSx8-hM3Dq-mCherry (n = 19, DREADD group) or AAV2/7-PRSx8-eGFP (n = 13, Controls). Three weeks later, LC unit recordings were performed in anesthetized rats. We investigated whether clozapine, a drug known to bind to modified neurons expressing hM3Dq receptors, was able to increase the LC firing rate. Baseline unit activity was recorded followed by subsequent administration of 0.01 and 0.1 mg/kg of clozapine in all rats. hM3Dq-mcherry expression levels were investigated using immunofluorescence staining of brainstem slices at the end of the experiment. Results Unit recordings could be performed in 12 rats and in a total of 12 neurons (DREADDs: n = 7, controls: n = 5). Clozapine 0.01 mg/kg did not affect the mean firing rate of recorded LC-neurons; 0.1 mg/kg induced an increased firing rate, irrespective whether neurons were recorded from DREADD or control rats (p = 0.006). Co-labeling of LC neurons and mCherry-tag showed that 20.6 ± 2.3% LC neurons expressed the hM3Dq receptor. Aspecific expression of hM3Dq-mCherry was also observed in non-LC neurons (26.0 ± 4.1%). Conclusion LC unit recording is feasible in an experimental set-up following manipulations for DREADD induction. A relatively low transduction efficiency of the used AAV was found. In view of this finding, the effect of injected clozapine on LC-NA could not be investigated as a reliable outcome parameter for activation of chemogenetically modified LC neurons. The use of AAV2/7, a vector previously applied successfully to target dopaminergic neurons in the substantia nigra, leads to insufficient chemogenetic modification of the LC compared to transduction with AAV2/9.
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Affiliation(s)
- Latoya Stevens
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Kristl Vonck
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Lars Emil Larsen
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Wouter Van Lysebettens
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Charlotte Germonpré
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Veerle Baekelandt
- Laboratory for Neurobiology and Gene Therapy, Center for Molecular Medicine, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Chris Van den Haute
- Laboratory for Neurobiology and Gene Therapy, Center for Molecular Medicine, Leuven Brain Institute, KU Leuven, Leuven, Belgium.,Leuven Viral Vector Core, Centre for Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Evelien Carrette
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Wytse Jan Wadman
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Paul Boon
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Robrecht Raedt
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
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23
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Tayebati SK, Cecchi A, Martinelli I, Carboni E, Amenta F. Pharmacotherapy of Down’s Syndrome: When and Which? CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2020; 18:750-757. [DOI: 10.2174/1871527318666191114092924] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 10/19/2019] [Accepted: 10/22/2019] [Indexed: 12/15/2022]
Abstract
:
Down Syndrome (DS) is an essential genetic disease that involves many other body systems
along with cerebral functions. The postnatal approach to treat this genetic disease includes intervention
on various related disorders (e.g., heart failure, respiratory, oral, ear, and hearing disorders). However,
different proposed treatments do not significantly improve the quality of life of these subjects. Another
approach to the treatment of DS considering the possibility to intervene on the embryo was recently
introduced. As of this, the current study has reviewed different outcomes regarding DS treatment in an
animal model, namely the Ts65Dn mouse. The obtained results encouraged spending more time, efforts,
and resources in this field. Besides, various treatment strategies were tried to include genetic
modification, treatment with vasoactive intestinal peptide derivatives or fluoxetine. However, the main
obstacle to the use of these possible treatments is the ethical issues it raises. The progression of the
pregnancy in spite of awareness that DS affects the unborn and prenatal treatment of DS injured embryo
are relevant dilemmas. Thus, talented researchers should spend more efforts to improve the quality
of life for people affected by DS, which will allow probably a better approach to the ethical issues.
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Affiliation(s)
- Seyed K. Tayebati
- School of Medicinal Sciences and Health Products, University of Camerino, Camerino, Italy
| | | | - Ilenia Martinelli
- School of Medicinal Sciences and Health Products, University of Camerino, Camerino, Italy
| | - Elisa Carboni
- Regional Centre for Prenatal Diagnosis, Loreto, Italy
| | - Francesco Amenta
- School of Medicinal Sciences and Health Products, University of Camerino, Camerino, Italy
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24
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Hamlett ED, Hjorth E, Ledreux A, Gilmore A, Schultzberg M, Granholm AC. RvE1 treatment prevents memory loss and neuroinflammation in the Ts65Dn mouse model of Down syndrome. Glia 2020; 68:1347-1360. [PMID: 31944407 DOI: 10.1002/glia.23779] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 12/18/2019] [Accepted: 12/19/2019] [Indexed: 12/23/2022]
Abstract
Inflammation can be resolved by pro-homeostatic lipids called specialized pro-resolving mediators (SPMs) upon activation of their receptors. Dysfunctional inflammatory resolution is now considered as a driver of chronic neuroinflammation and Alzheimer's disease (AD) pathogenesis. We have previously shown that SPM levels were reduced and also that SPM-binding receptors were increased in patients with AD compared to age-matched controls. Individuals with Down syndrome (DS) exhibit accelerated acquisition of AD neuropathology, dementia, and neuroinflammation at an earlier age than the general population. Beneficial effects of inducing resolution in DS have not been investigated previously. The effects of the SPM resolvin E1 (RvE1) in a DS mouse model (Ts65Dn) were investigated with regard to inflammation, neurodegeneration, and memory deficits. A moderate dose of RvE1 for 4 weeks in middle-aged Ts65Dn mice elicited a significant reduction in memory loss, along with reduced levels of serum pro-inflammatory cytokines, and reduced microglial activation in the hippocampus of Ts65Dn mice but had no effects in age-matched normosomic mice. There were no observable adverse side effects in Ts65Dn or in normosomic mice. These findings suggest that SPMs may represent a novel drug target for individuals with DS and others at risk of developing AD.
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Affiliation(s)
- Eric D Hamlett
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Erik Hjorth
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Stockholm, Sweden
| | - Aurélie Ledreux
- Knoebel Institute for Healthy Aging and the Department of Biological Sciences, University of Denver, Denver, Colorado
| | - Anah Gilmore
- Knoebel Institute for Healthy Aging and the Department of Biological Sciences, University of Denver, Denver, Colorado
| | - Marianne Schultzberg
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Stockholm, Sweden
| | - Ann Charlotte Granholm
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Stockholm, Sweden
- Knoebel Institute for Healthy Aging and the Department of Biological Sciences, University of Denver, Denver, Colorado
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25
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Cannavo C, Tosh J, Fisher EMC, Wiseman FK. Using mouse models to understand Alzheimer's disease mechanisms in the context of trisomy of chromosome 21. PROGRESS IN BRAIN RESEARCH 2019; 251:181-208. [PMID: 32057307 DOI: 10.1016/bs.pbr.2019.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
People who have Down syndrome are at significantly elevated risk of developing early onset Alzheimer's disease that causes dementia (AD-DS). Here we review recent progress in modeling the development of AD-DS in mouse models. These studies provide insight into mechanisms underlying Alzheimer's disease and generate new clinical research questions. In addition, they suggest potential new targets for disease prevention therapies.
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Affiliation(s)
- Claudia Cannavo
- Department of Neuromuscular Diseases, UCL Institute of Neurology, London, United Kingdom; UK Dementia Research Institute at University College, London, United Kingdom
| | - Justin Tosh
- Department of Neuromuscular Diseases, UCL Institute of Neurology, London, United Kingdom
| | - Elizabeth M C Fisher
- Department of Neuromuscular Diseases, UCL Institute of Neurology, London, United Kingdom; The London Down Syndrome Consortium (LonDownS), London, United Kingdom
| | - Frances K Wiseman
- Department of Neuromuscular Diseases, UCL Institute of Neurology, London, United Kingdom; The London Down Syndrome Consortium (LonDownS), London, United Kingdom; UK Dementia Research Institute at University College, London, United Kingdom.
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26
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Hamlett ED, Ledreux A, Gilmore A, Vazey EM, Aston-Jones G, Boger HA, Paredes D, Granholm ACE. Inhibitory designer receptors aggravate memory loss in a mouse model of down syndrome. Neurobiol Dis 2019; 134:104616. [PMID: 31678403 DOI: 10.1016/j.nbd.2019.104616] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 08/06/2019] [Accepted: 09/17/2019] [Indexed: 12/20/2022] Open
Abstract
The pontine nucleus locus coeruleus (LC) is the primary source of noradrenergic (NE) projections to the brain and is important for working memory, attention, and cognitive flexibility. Individuals with Down syndrome (DS) develop Alzheimer's disease (AD) with high penetrance and often exhibit working memory deficits coupled with degeneration of LC-NE neurons early in the progression of AD pathology. Designer receptors exclusively activated by designer drugs (DREADDs) are chemogenetic tools that allow targeted manipulation of discrete neuronal populations in the brain without the confounds of off-target effects. We utilized male Ts65Dn mice (a mouse model for DS), and male normosomic (NS) controls to examine the effects of inhibitory DREADDs delivered via an AAV vector under translational control of the synthetic PRSx8, dopamine β hydroxylase (DβH) promoter. This chemogenetic tool allowed LC inhibition upon administration of the inert DREADD ligand, clozapine-N-oxide (CNO). DREADD-mediated LC inhibition impaired performance in a novel object recognition task and reversal learning in a spatial task. DREADD-mediated LC inhibition gave rise to an elevation of α-adrenoreceptors both in NS and in Ts65Dn mice. Further, microglial markers showed that the inhibitory DREADD stimulation led to increased microglial activation in the hippocampus in Ts65Dn but not in NS mice. These findings strongly suggest that LC signaling is important for intact memory and learning in Ts65Dn mice and disruption of these neurons leads to increased inflammation and dysregulation of adrenergic receptors.
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Affiliation(s)
- Eric D Hamlett
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC 29425, USA.
| | - Aurélie Ledreux
- Knoebel Institute for Healthy Aging, University of Denver, Denver, CO 80208, USA
| | - Anah Gilmore
- Knoebel Institute for Healthy Aging, University of Denver, Denver, CO 80208, USA
| | - Elena M Vazey
- Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Gary Aston-Jones
- Rutgers Brain Health Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Heather A Boger
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Daniel Paredes
- Knoebel Institute for Healthy Aging, University of Denver, Denver, CO 80208, USA
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27
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Abstract
Over the past decade, basic sleep research investigating the circuitry controlling sleep and wakefulness has been boosted by pharmacosynthetic approaches, including chemogenetic techniques using designed receptors exclusively activated by designer drugs (DREADD). DREADD offers a series of tools that selectively control neuronal activity as a way to probe causal relationship between neuronal sub-populations and the regulation of the sleep-wake cycle. Following the path opened by optogenetics, DREADD tools applied to discrete neuronal sub-populations in numerous brain areas quickly made their contribution to the discovery and the expansion of our understanding of critical brain structures involved in a wide variety of behaviors and in the control of vigilance state architecture.
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28
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Panthi S, Leitch B. The impact of silencing feed-forward parvalbumin-expressing inhibitory interneurons in the cortico-thalamocortical network on seizure generation and behaviour. Neurobiol Dis 2019; 132:104610. [PMID: 31494287 DOI: 10.1016/j.nbd.2019.104610] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 08/10/2019] [Accepted: 09/04/2019] [Indexed: 12/14/2022] Open
Abstract
Feed-forward inhibition (FFI) is an essential mechanism within the brain, to regulate neuronal firing and prevent runaway excitation. In the cortico-thalamocortical (CTC) network, fast spiking parvalbumin-expressing (PV+) inhibitory interneurons regulate the firing of pyramidal cells in the cortex and relay neurons in the thalamus. PV+ interneuron dysfunction has been implicated in several neurological disorders, including epilepsy. Previously, we demonstrated that loss of excitatory AMPA-receptors, specifically at synapses on PV+ interneurons in CTC feedforward microcircuits, occurs in the stargazer mouse model of absence epilepsy. These mice present with absence seizures characterized by spike and wave discharges (SWDs) on electroencephalogram (EEG) and concomitant behavioural arrest, similar to childhood absence epilepsy. The aim of the current study was to investigate the impact of loss of FFI within the CTC on absence seizure generation and behaviour using new Designer Receptor Exclusively Activated by Designer Drug (DREADD) technology. We crossed PV-Cre mice with Cre-dependent hM4Di DREADD strains of mice, which allowed Cre-recombinase-mediated restricted expression of inhibitory Gi-DREADDs in PV+ interneurons. We then tested the impact of global and focal (within the CTC network) silencing of PV+ interneurons. CNO mediated silencing of all PV+ interneurons by intraperitoneal injection caused the impairment of motor control, decreased locomotion and increased anxiety in a dose-dependent manner. Such silencing generated pathological oscillations similar to absence-like seizures. Focal silencing of PV+ interneurons within cortical or thalamic feedforward microcircuits, induced SWD-like oscillations and associated behavioural arrest. Epileptiform activity on EEG appeared significantly sooner after focal injection compared to peripheral injection of CNO. However, the mean duration of each oscillatory burst and spike frequency was similar, irrespective of mode of CNO delivery. No significant changes were observed in vehicle-treated or non-DREADD wild-type control animals. These data suggest that dysfunctional feed-forward inhibition in CTC microcircuits may be an important target for future therapy strategies for some patients with absence seizures. Additionally, silencing of PV+ interneurons in other brain regions may contribute to anxiety related neurological and psychiatric disorders.
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Affiliation(s)
- Sandesh Panthi
- Department of Anatomy, School of Biomedical Sciences, and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Beulah Leitch
- Department of Anatomy, School of Biomedical Sciences, and Brain Health Research Centre, University of Otago, Dunedin, New Zealand.
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29
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Kahn JB, Port RG, Yue C, Takano H, Coulter DA. Circuit-based interventions in the dentate gyrus rescue epilepsy-associated cognitive dysfunction. Brain 2019; 142:2705-2721. [PMID: 31363737 PMCID: PMC6736326 DOI: 10.1093/brain/awz209] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 04/26/2019] [Accepted: 05/22/2019] [Indexed: 12/15/2022] Open
Abstract
Temporal lobe epilepsy is associated with significant structural pathology in the hippocampus. In the dentate gyrus, the summative effect of these pathologies is massive hyperexcitability in the granule cells, generating both increased seizure susceptibility and cognitive deficits. To date, therapeutic approaches have failed to improve the cognitive symptoms in fully developed, chronic epilepsy. As the dentate's principal signalling population, the granule cells' aggregate excitability has the potential to provide a mechanistically-independent downstream target. We examined whether normalizing epilepsy-associated granule cell hyperexcitability-without correcting the underlying structural circuit disruptions-would constitute an effective therapeutic approach for cognitive dysfunction. In the systemic pilocarpine mouse model of temporal lobe epilepsy, the epileptic dentate gyrus excessively recruits granule cells in behavioural contexts, not just during seizure events, and these mice fail to perform on a dentate-mediated spatial discrimination task. Acutely reducing dorsal granule cell hyperactivity in chronically epileptic mice via either of two distinct inhibitory chemogenetic receptors rescued behavioural performance such that they responded comparably to wild type mice. Furthermore, recreating granule cell hyperexcitability in control mice via excitatory chemogenetic receptors, without altering normal circuit anatomy, recapitulated spatial memory deficits observed in epileptic mice. However, making the granule cells overly quiescent in both epileptic and control mice again disrupted behavioural performance. These bidirectional manipulations reveal that there is a permissive excitability window for granule cells that is necessary to support successful behavioural performance. Chemogenetic effects were specific to the targeted dorsal hippocampus, as hippocampal-independent and ventral hippocampal-dependent behaviours remained unaffected. Fos expression demonstrated that chemogenetics can modulate granule cell recruitment via behaviourally relevant inputs. Rather than driving cell activity deterministically or spontaneously, chemogenetic intervention merely modulates the behaviourally permissive activity window in which the circuit operates. We conclude that restoring appropriate principal cell tuning via circuit-based therapies, irrespective of the mechanisms generating the disease-related hyperactivity, is a promising translational approach.
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Affiliation(s)
- Julia B Kahn
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Russell G Port
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- The Research Institute of the Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Cuiyong Yue
- The Research Institute of the Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Hajime Takano
- The Research Institute of the Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Douglas A Coulter
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- The Research Institute of the Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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30
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Rapid Reconfiguration of the Functional Connectome after Chemogenetic Locus Coeruleus Activation. Neuron 2019; 103:702-718.e5. [DOI: 10.1016/j.neuron.2019.05.034] [Citation(s) in RCA: 130] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/15/2019] [Accepted: 05/21/2019] [Indexed: 12/14/2022]
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31
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Jacobson L. Glucocorticoid receptor deletion from locus coeruleus norepinephrine neurons promotes depression-like social withdrawal in female but not male mice. Brain Res 2018; 1710:82-91. [PMID: 30576626 DOI: 10.1016/j.brainres.2018.12.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 11/26/2018] [Accepted: 12/17/2018] [Indexed: 01/21/2023]
Abstract
Abnormal glucocorticoid levels can cause psychiatric symptoms ranging from depression to euphoria that have been implicated in mood disorders. My overarching hypothesis is that these opposing effects are mediated by glucocorticoid receptors (GR) in different brain regions. My laboratory has shown that GR in the serotonergic dorsal raphé nucleus (DRN) promote depression-like social and behavioral withdrawal in mice. We have also shown that GR in the DRN and noradrenergic locus coeruleus (LC) exhibit divergent regulation by antidepressants that have differential efficacy for depression subtypes with opposing abnormalities in glucocorticoids. The current study tested the hypothesis that LC GR would have effects opposite to those in the DRN by preventing rather than promoting social withdrawal. GR was deleted from LC NE neurons in female and male floxed GR mice by bilateral injections of lentivirus transducing Cre recombinase under control of a multimerized Phox 2a/2b response sequence (PRS) from the dopamine β-hydroxylase promoter (PRS-Cre). Female but not male PRS-Cre mice exhibited lower social interaction compared to controls injected with lentivirus transducing green fluorescent protein (PRS-GFP). Differences in social interaction between PRS-GFP and PRS-Cre females were not associated with differences in exploratory behavior, plasma corticosterone, male-female differences in LC GR expression, or changes in LC mineralocorticoid receptor or tyrosine hydroxylase gene expression. These results indicate that LC NE GR have sex-dependent effects to prevent social withdrawal, supporting the concept that glucocorticoids exert opposing effects on depression symptoms via different brain targets, and potentially revealing novel drug targets to treat depression, particularly in women.
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Affiliation(s)
- Lauren Jacobson
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, USA.
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32
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Herault Y, Delabar JM, Fisher EMC, Tybulewicz VLJ, Yu E, Brault V. Rodent models in Down syndrome research: impact and future opportunities. Dis Model Mech 2018; 10:1165-1186. [PMID: 28993310 PMCID: PMC5665454 DOI: 10.1242/dmm.029728] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Down syndrome is caused by trisomy of chromosome 21. To date, a multiplicity of mouse models with Down-syndrome-related features has been developed to understand this complex human chromosomal disorder. These mouse models have been important for determining genotype-phenotype relationships and identification of dosage-sensitive genes involved in the pathophysiology of the condition, and in exploring the impact of the additional chromosome on the whole genome. Mouse models of Down syndrome have also been used to test therapeutic strategies. Here, we provide an overview of research in the last 15 years dedicated to the development and application of rodent models for Down syndrome. We also speculate on possible and probable future directions of research in this fast-moving field. As our understanding of the syndrome improves and genome engineering technologies evolve, it is necessary to coordinate efforts to make all Down syndrome models available to the community, to test therapeutics in models that replicate the whole trisomy and design new animal models to promote further discovery of potential therapeutic targets. Summary: Mouse models have boosted therapeutic options for Down syndrome, and improved models are being developed to better understand the pathophysiology of this genetic condition.
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Affiliation(s)
- Yann Herault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, 1 rue Laurent Fries, 67404 Illkirch, France .,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France.,T21 Research Society, Brain and Spine Institute (ICM), 75013 Paris
| | - Jean M Delabar
- T21 Research Society, Brain and Spine Institute (ICM), 75013 Paris.,Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, UMR8251, CNRS, 75205 Paris, France.,INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et la Moelle épinière, ICM, 75013 Paris, France.,Brain and Spine Institute (ICM) CNRS UMR7225, INSERM UMRS 975, 75013 Paris, France
| | - Elizabeth M C Fisher
- T21 Research Society, Brain and Spine Institute (ICM), 75013 Paris.,Department of Neurodegenerative Disease, Institute of Neurology, University College London, London, WC1N 3BG, UK.,LonDownS Consortium, London, W1T 7NF UK
| | - Victor L J Tybulewicz
- T21 Research Society, Brain and Spine Institute (ICM), 75013 Paris.,LonDownS Consortium, London, W1T 7NF UK.,The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.,Department of Medicine, Imperial College, London, SW7 2AZ, UK
| | - Eugene Yu
- T21 Research Society, Brain and Spine Institute (ICM), 75013 Paris.,The Children's Guild Foundation Down Syndrome Research Program, Department of Cancer Genetics and Genetics Program, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.,Department of Cellular and Molecular Biology, Roswell Park Division of Graduate School, Genetics, Genomics and Bioinformatics Program, State University of New York at Buffalo, Buffalo, NY 14263, USA
| | - Veronique Brault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, 1 rue Laurent Fries, 67404 Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France
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33
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Wei J, Zhong P, Qin L, Tan T, Yan Z. Chemicogenetic Restoration of the Prefrontal Cortex to Amygdala Pathway Ameliorates Stress-Induced Deficits. Cereb Cortex 2018; 28:1980-1990. [PMID: 28498919 PMCID: PMC6018994 DOI: 10.1093/cercor/bhx104] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 03/27/2017] [Indexed: 01/11/2023] Open
Abstract
Corticosteroid stress hormones exert a profound impact on cognitive and emotional processes. Understanding the neuronal circuits that are altered by chronic stress is important for counteracting the detrimental effects of stress in a brain region- and cell type-specific manner. Using the chemogenetic tool, Designer Receptors Exclusively Activated by Designer Drugs (DREADDs), which enables the remote, noninvasive and long-lasting modulation of cellular activity and signal transduction in discrete neuronal populations in vivo, we sought to identify the specific pathways that play an essential role in stress responses. We found that prolonged severe stress induced the diminished glutamatergic projection from pyramidal neurons in prefrontal cortex (PFC) to GABAergic interneurons in basolateral amygdala (BLA), leading to the loss of feedforward inhibition and ensuing hyperexcitability of BLA principal neurons, which caused a variety of behavioral abnormalities. Activating PFC pyramidal neurons with hM3D(Gq) DREADD restored the functional connection between PFC and BLA in stressed animals, resulting in the rescue of recognition memory, normalization of locomotor activity and reduction of aggressive behaviors. Inhibiting BLA principal neurons directly with hM4D(Gi) DREADD also blocked BLA hyperactivity and aggressive behaviors in stressed animals. These results have offered an effective avenue to counteract the stress-induced disruption of circuitry homeostasis.
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Affiliation(s)
- Jing Wei
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14214, USA
- Medical Research, VA Western New York Healthcare System, Buffalo, NY 14215, USA
| | - Ping Zhong
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14214, USA
- Medical Research, VA Western New York Healthcare System, Buffalo, NY 14215, USA
| | - Luye Qin
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14214, USA
| | - Tao Tan
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14214, USA
| | - Zhen Yan
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14214, USA
- Medical Research, VA Western New York Healthcare System, Buffalo, NY 14215, USA
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Caraci F, Iulita MF, Pentz R, Flores Aguilar L, Orciani C, Barone C, Romano C, Drago F, Cuello AC. Searching for new pharmacological targets for the treatment of Alzheimer's disease in Down syndrome. Eur J Pharmacol 2017; 817:7-19. [DOI: 10.1016/j.ejphar.2017.10.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 09/26/2017] [Accepted: 10/04/2017] [Indexed: 11/26/2022]
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Rorabaugh JM, Chalermpalanupap T, Botz-Zapp CA, Fu VM, Lembeck NA, Cohen RM, Weinshenker D. Chemogenetic locus coeruleus activation restores reversal learning in a rat model of Alzheimer's disease. Brain 2017; 140:3023-3038. [PMID: 29053824 PMCID: PMC5841201 DOI: 10.1093/brain/awx232] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Revised: 07/14/2017] [Accepted: 07/18/2017] [Indexed: 01/17/2023] Open
Abstract
See Grinberg and Heinsen (doi:10.1093/brain/awx261) for a scientific commentary on this article. Clinical evidence suggests that aberrant tau accumulation in the locus coeruleus and noradrenergic dysfunction may be a critical early step in Alzheimer’s disease progression. Yet, an accurate preclinical model of these phenotypes that includes early pretangle tau accrual in the locus coeruleus, loss of locus coeruleus innervation and deficits locus coeruleus/norepinephrine modulated behaviours, does not exist, hampering the identification of underlying mechanisms and the development of locus coeruleus-based therapies. Here, a transgenic rat (TgF344-AD) expressing disease-causing mutant amyloid precursor protein (APPsw) and presenilin-1 (PS1ΔE9) was characterized for histological and behavioural signs of locus coeruleus dysfunction reminiscent of mild cognitive impairment/early Alzheimer’s disease. In TgF344-AD rats, hyperphosphorylated tau was detected in the locus coeruleus prior to accrual in the medial entorhinal cortex or hippocampus, and tau pathology in the locus coeruleus was negatively correlated with noradrenergic innervation in the medial entorhinal cortex. Likewise, TgF344-AD rats displayed progressive loss of hippocampal norepinephrine levels and locus coeruleus fibres in the medial entorhinal cortex and dentate gyrus, with no frank noradrenergic cell body loss. Cultured mouse locus coeruleus neurons expressing hyperphosphorylation-prone mutant human tau had shorter neurites than control neurons, but similar cell viability, suggesting a causal link between pretangle tau accrual and altered locus coeruleus fibre morphology. TgF344-AD rats had impaired reversal learning in the Morris water maze compared to their wild-type littermates, which was rescued by chemogenetic locus coeruleus activation via designer receptors exclusively activated by designer drugs (DREADDs). Our results indicate that TgF344-AD rats uniquely meet several key criteria for a suitable model of locus coeruleus pathology and dysfunction early in Alzheimer’s disease progression, and suggest that a substantial window of opportunity for locus coeruleus/ norepinephrine-based therapeutics exists.
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Affiliation(s)
- Jacki M Rorabaugh
- Department of Human Genetics, Emory University School of Medicine, Atlanta GA 30322, USA
| | | | - Christian A Botz-Zapp
- Department of Human Genetics, Emory University School of Medicine, Atlanta GA 30322, USA
| | - Vanessa M Fu
- Department of Human Genetics, Emory University School of Medicine, Atlanta GA 30322, USA
| | - Natalie A Lembeck
- Department of Human Genetics, Emory University School of Medicine, Atlanta GA 30322, USA
| | - Robert M Cohen
- Departments of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta GA 30322, USA
| | - David Weinshenker
- Department of Human Genetics, Emory University School of Medicine, Atlanta GA 30322, USA
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Chalermpalanupap T, Weinshenker D, Rorabaugh JM. Down but Not Out: The Consequences of Pretangle Tau in the Locus Coeruleus. Neural Plast 2017; 2017:7829507. [PMID: 29038736 PMCID: PMC5605916 DOI: 10.1155/2017/7829507] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 06/20/2017] [Accepted: 07/20/2017] [Indexed: 12/12/2022] Open
Abstract
Degeneration of locus coeruleus (LC) is an underappreciated hallmark of Alzheimer's disease (AD). The LC is the main source of norepinephrine (NE) in the forebrain, and its degeneration is highly correlated with cognitive impairment and amyloid-beta (Aβ) and tangle pathology. Hyperphosphorylated tau in the LC is among the first detectable AD-like neuropathology in the brain, and while the LC/NE system impacts multiple aspects of AD (e.g., cognition, neuropathology, and neuroinflammation), the functional consequences of hyperphosphorylated tau accrual on LC neurons are not known. Recent evidence suggests that LC neurons accumulate aberrant tau species for decades before frank LC cell body degeneration occurs in AD, suggesting that a therapeutic window exists. In this review, we combine the literature on how pathogenic tau affects forebrain neurons with the known properties and degeneration patterns of LC neurons to synthesize hypotheses on hyperphosphorylated tau-induced dysfunction of LC neurons and the prion-like spread of pretangle tau from the LC to the forebrain. We also propose novel experiments using both in vitro and in vivo models to address the many questions surrounding the impact of hyperphosphorylated tau on LC neurons in AD and its role in disease progression.
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Affiliation(s)
| | - David Weinshenker
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jacki M. Rorabaugh
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
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Resolving Behavioral Output via Chemogenetic Designer Receptors Exclusively Activated by Designer Drugs. J Neurosci 2017; 36:9268-82. [PMID: 27605603 DOI: 10.1523/jneurosci.1333-16.2016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 07/13/2016] [Indexed: 12/26/2022] Open
Abstract
Designer receptors exclusively activated by designer drugs (DREADDs) have proven to be highly effective neuromodulatory tools for the investigation of neural circuits underlying behavioral outputs. They exhibit a number of advantages: they rely on cell-specific manipulations through canonical intracellular signaling pathways, they are easy and cost-effective to implement in a laboratory setting, and they are easily scalable for single-region or full-brain manipulations. On the other hand, DREADDs rely on ligand-G-protein-coupled receptor interactions, leading to coarse temporal dynamics. In this review we will provide a brief overview of DREADDs, their implementation, and the advantages and disadvantages of their use in animal systems. We also will provide numerous examples of their use across a broad variety of biomedical research fields.
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Abstract
Altered concentrations of monoamine neurotransmitters and metabolites have been repeatedly found in people with Down syndrome (DS, trisomy 21). Because of the limited availability of human post-mortem tissue, DS mouse models are of great interest to study these changes and the underlying neurobiological mechanisms. Although previous studies have shown the potential of Ts65Dn mice – the most widely used mouse model of DS – to model noradrenergic changes, a comprehensive monoaminergic characterization in multiple brain regions has not been performed so far. Here, we used RP-HPLC with electrochemical detection to quantify (nor)adrenergic (NA, adrenaline and MHPG), dopaminergic (DA, HVA and DOPAC), and serotonergic compounds (tryptophan, 5-HT and 5-HIAA) in ten regionally dissected brain regions of Ts65Dn mice, as well as in Dp1Tyb mice – a novel DS mouse model. Comparing young adult aneuploid mice (2.5–5.5 months) with their euploid WT littermates did not reveal generalized monoaminergic dysregulation, indicating that the genetic overload in these mice barely affected the absolute concentrations at this age. Moreover, we studied the effect of aging in Ts65Dn mice: comparing aged animals (12–13 months) with their younger counterparts revealed a large number of significant changes. In general, the (nor)adrenergic system appeared to be reduced, while serotonergic compounds were increased with aging. Dopaminergic alterations were less consistent. These overall patterns appeared to be relatively similar for Ts65Dn and WT mice, though more observed changes were regarded significant for WT mice. Similar human post-mortem studies are necessary to validate the monoaminergic construct validity of the Ts65Dn and Dp1Typ mouse models. Monoamine neurotransmitters and metabolites appear to be altered in Down syndrome. The monoaminergic brain profile of two Down syndrome mouse models was examined. Aneuploidy barely affected monoamines in Ts65Dn and Dp1Tyb mice vs. wild-type mice. Aging to 12–13 months showed strong monoaminergic changes in the Ts65Dn mouse model. Construct validity needs to be established by similar human post-mortem studies.
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Solis M. Controlling Seizures Through Chemogenetics: A New Technique May Provide a More Precise Way of Targeting Faulty Circuitry in the Brain. IEEE Pulse 2017; 7:26-30. [PMID: 28113165 DOI: 10.1109/mpul.2016.2592298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Electricity is the currency of our nervous systems. Thinking and planning, walking and talking, eating and sleeping-all our mental and physical activities are driven by electrical signals moving through the brain. This electrical traffic ebbs and flows in consistent patterns across different brain regions, carrying information from one neuron to the next.
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Xing Z, Li Y, Pao A, Bennett AS, Tycko B, Mobley WC, Yu YE. Mouse-based genetic modeling and analysis of Down syndrome. Br Med Bull 2016; 120:111-122. [PMID: 27789459 PMCID: PMC5146682 DOI: 10.1093/bmb/ldw040] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 09/07/2016] [Accepted: 10/03/2016] [Indexed: 11/12/2022]
Abstract
INTRODUCTION Down syndrome (DS), caused by human trisomy 21 (Ts21), can be considered as a prototypical model for understanding the effects of chromosomal aneuploidies in other diseases. Human chromosome 21 (Hsa21) is syntenically conserved with three regions in the mouse genome. SOURCES OF DATA A review of recent advances in genetic modeling and analysis of DS. Using Cre/loxP-mediated chromosome engineering, a substantial number of new mouse models of DS have recently been generated, which facilitates better understanding of disease mechanisms in DS. AREAS OF AGREEMENT Based on evolutionary conservation, Ts21 can be modeled by engineered triplication of Hsa21 syntenic regions in mice. The validity of the models is supported by the exhibition of DS-related phenotypes. AREAS OF CONTROVERSY Although substantial progress has been made, it remains a challenge to unravel the relative importance of specific candidate genes and molecular mechanisms underlying the various clinical phenotypes. GROWING POINTS Further understanding of mechanisms based on data from mouse models, in parallel with human studies, may lead to novel therapies for clinical manifestations of Ts21 and insights to the roles of aneuploidies in other developmental disorders and cancers.
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Affiliation(s)
- Zhuo Xing
- The Children's Guild Foundation Down Syndrome Research Program, Genetics Program and Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
| | - Yichen Li
- The Children's Guild Foundation Down Syndrome Research Program, Genetics Program and Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
| | - Annie Pao
- The Children's Guild Foundation Down Syndrome Research Program, Genetics Program and Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
| | - Abigail S Bennett
- The Children's Guild Foundation Down Syndrome Research Program, Genetics Program and Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
| | - Benjamin Tycko
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain and Institute for Cancer Genetics, Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, USA
| | - William C Mobley
- Department of Neurosciences, School of Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Y Eugene Yu
- The Children's Guild Foundation Down Syndrome Research Program, Genetics Program and Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA .,Cellular and Molecular Biology Program, Roswell Park Division of Graduate School, Genetics, Genomics and Bioinformatics Program, State University of New York at Buffalo, Buffalo, NY 14263, USA
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Prömel S, Fiedler F, Binder C, Winkler J, Schöneberg T, Thor D. Deciphering and modulating G protein signalling in C. elegans using the DREADD technology. Sci Rep 2016; 6:28901. [PMID: 27461895 PMCID: PMC4962097 DOI: 10.1038/srep28901] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 06/10/2016] [Indexed: 12/14/2022] Open
Abstract
G-protein signalling is an evolutionary conserved concept highlighting its fundamental impact on developmental and functional processes. Studies on the effects of G protein signals on tissues as well as an entire organism are often conducted in Caenorhabditis elegans. To understand and control dynamics and kinetics of the processes involved, pharmacological modulation of specific G protein pathways would be advantageous, but is difficult due to a lack in accessibility and regulation. To provide this option, we designed G protein-coupled receptor-based designer receptors (DREADDs) for C. elegans. Initially described in mammalian systems, these modified muscarinic acetylcholine receptors are activated by the inert drug clozapine-N-oxide, but not by their endogenous agonists. We report a novel C. elegans-specific DREADD, functionally expressed and specifically activating Gq-protein signalling in vitro and in vivo which we used for modulating mating behaviour. Therefore, this novel designer receptor demonstrates the possibility to pharmacologically control physiological functions in C. elegans.
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Affiliation(s)
- Simone Prömel
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Franziska Fiedler
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Claudia Binder
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Jana Winkler
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Torsten Schöneberg
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Doreen Thor
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
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Whissell PD, Tohyama S, Martin LJ. The Use of DREADDs to Deconstruct Behavior. Front Genet 2016; 7:70. [PMID: 27242888 PMCID: PMC4868840 DOI: 10.3389/fgene.2016.00070] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 04/12/2016] [Indexed: 02/03/2023] Open
Abstract
A central goal in understanding brain function is to link specific cell populations to behavioral outputs. In recent years, the selective targeting of specific neural circuits has been made possible with the development of new experimental approaches, including chemogenetics. This technique allows for the control of molecularly defined subsets of cells through engineered G protein-coupled receptors (GPCRs), which have the ability to activate or silence neuronal firing. Through chemogenetics, neural circuits are being linked to behavioral outputs at an unprecedented rate. Further, the coupling of chemogenetics with imaging techniques to monitor neural activity in freely moving animals now makes it possible to deconstruct the complex whole-brain networks that are fundamental to behavioral states. In this review, we highlight a specific chemogenetic application known as DREADDs (designer receptors exclusively activated by designer drugs). DREADDs are used ubiquitously to modulate GPCR activity in vivo and have been widely applied in the basic sciences, particularly in the field of behavioral neuroscience. Here, we focus on the impact and utility of DREADD technology in dissecting the neural circuitry of various behaviors including memory, cognition, reward, feeding, anxiety and pain. By using DREADDs to monitor the electrophysiological, biochemical, and behavioral outputs of specific neuronal types, researchers can better understand the links between brain activity and behavior. Additionally, DREADDs are useful in studying the pathogenesis of disease and may ultimately have therapeutic potential.
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Affiliation(s)
- Paul D Whissell
- Department of Psychology, University of Toronto Toronto, ON, Canada
| | - Sarasa Tohyama
- Department of Psychology, University of Toronto Mississauga Mississauga, ON, Canada
| | - Loren J Martin
- Department of Psychology, University of Toronto Mississauga Mississauga, ON, Canada
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López AJ, Kramár E, Matheos DP, White AO, Kwapis J, Vogel-Ciernia A, Sakata K, Espinoza M, Wood MA. Promoter-Specific Effects of DREADD Modulation on Hippocampal Synaptic Plasticity and Memory Formation. J Neurosci 2016; 36:3588-99. [PMID: 27013687 PMCID: PMC4804014 DOI: 10.1523/jneurosci.3682-15.2016] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 01/20/2016] [Accepted: 02/15/2016] [Indexed: 11/21/2022] Open
Abstract
Designer receptors exclusively activated by designer drug (DREADDs) are a novel tool with the potential to bidirectionally drive cellular, circuit, and ultimately, behavioral changes. We used DREADDs to evaluate memory formation in a hippocampus-dependent task in mice and effects on synaptic physiology in the dorsal hippocampus. We expressed neuron-specific (hSyn promoter) DREADDs that were either excitatory (HM3D) or inhibitory (HM4D) in the dorsal hippocampus. As predicted, hSyn-HM3D was able to transform a subthreshold learning event into long-term memory (LTM), and hSyn-HM4D completely impaired LTM formation. Surprisingly, the opposite was observed during experiments examining the effects on hippocampal long-term potentiation (LTP). hSyn-HM3D impaired LTP and hSyn-HM4D facilitated LTP. Follow-up experiments indicated that the hSyn-HM3D-mediated depression of fEPSP appears to be driven by presynaptic activation of inhibitory currents, whereas the hSyn-HM4D-mediated increase of fEPSP is induced by a reduction in GABAA receptor function. To determine whether these observations were promoter specific, we next examined the effects of using the CaMKIIα promoter that limits expression to forebrain excitatory neurons. CaMKIIα-HM3D in the dorsal hippocampus led to the transformation of a subthreshold learning event into LTM, whereas CaMKIIα-HM4D blocked LTM formation. Consistent with these findings, baseline synaptic transmission and LTP was increased in CaMKIIα-HM3D hippocampal slices, whereas slices from CaMKIIα-HM4D mice produced expected decreases in baseline synaptic transmission and LTP. Together, these experiments further demonstrate DREADDs as being a robust and reliable means of modulating neuronal function to manipulate long-term changes in behavior, while providing evidence for specific dissociations between LTM and LTP. SIGNIFICANCE STATEMENT This study evaluates the efficacy of designer receptors exclusively activated by designer drug (DREADDs) as a means of bidirectionally modulating the hippocampus in not only a hippocampus-dependent task but also in hippocampal synaptic plasticity. This is the first study to evaluate the effects of DREADD-mediated inhibition and excitation in hippocampal long-term potentiation. More specifically, this study evaluates the effect of promoter-specific expression of DREADD viruses in a heterogenic cell population, which revealed surprising effects of different promoters. With chemogenetics becoming a more ubiquitous tool throughout studies investigating circuit-specific function, these data are of broad interest to the neuroscientific community because we have shown that promoter-specific effects can drastically alter synaptic function within a specific region, without parallel changes at the level of behavior.
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Affiliation(s)
- Alberto J López
- Department of Neurobiology and Behavior and Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, California 92697, UC Irvine Center for Addiction Neuroscience, and
| | - Enikö Kramár
- Department of Neurobiology and Behavior and Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, California 92697, UC Irvine Center for Addiction Neuroscience, and
| | - Dina P Matheos
- Department of Neurobiology and Behavior and Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, California 92697, UC Irvine Center for Addiction Neuroscience, and
| | - André O White
- Department of Neurobiology and Behavior and Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, California 92697, UC Irvine Center for Addiction Neuroscience, and
| | - Janine Kwapis
- Department of Neurobiology and Behavior and Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, California 92697, UC Irvine Center for Addiction Neuroscience, and
| | - Annie Vogel-Ciernia
- Davis M.I.N.D. Institute, University of California, Davis, Davis, California 96516
| | - Keith Sakata
- Department of Neurobiology and Behavior and Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, California 92697, UC Irvine Center for Addiction Neuroscience, and
| | - Monica Espinoza
- Department of Neurobiology and Behavior and Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, California 92697, UC Irvine Center for Addiction Neuroscience, and
| | - Marcelo A Wood
- Department of Neurobiology and Behavior and Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, California 92697, UC Irvine Center for Addiction Neuroscience, and
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Smith KS, Bucci DJ, Luikart BW, Mahler SV. DREADDS: Use and application in behavioral neuroscience. Behav Neurosci 2016; 130:137-55. [PMID: 26913540 DOI: 10.1037/bne0000135] [Citation(s) in RCA: 162] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Technological advances over the last decade are changing the face of behavioral neuroscience research. Here we review recent work on the use of one such transformative tool in behavioral neuroscience research, chemogenetics (or Designer Receptors Exclusively Activated by Designer Drugs, DREADDS). As transformative technologies such as DREADDs are introduced, applied, and refined, their utility in addressing complex questions about behavior and cognition becomes clear and exciting. In the behavioral neuroscience field, remarkable new findings now regularly appear as a result of the ability to monitor and intervene in neural processes with high anatomical precision as animals behave in complex task environments. As these new tools are applied to behavioral questions, individualized procedures for their use find their way into diverse labs. Thus, "tips of the trade" become important for wide dissemination not only for laboratories that are using the tools but also for those who are interested in incorporating them into their own work. Our aim is to provide an up-to-date perspective on how the DREADD technique is being used for research on learning and memory, decision making, and goal-directed behavior, as well as to provide suggestions and considerations for current and future users based on our collective experience. (PsycINFO Database Record
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Affiliation(s)
- Kyle S Smith
- Department of Psychological and Brain Sciences, Dartmouth College
| | - David J Bucci
- Department of Psychological and Brain Sciences, Dartmouth College
| | - Bryan W Luikart
- Department of Physiology and Neurobiology, Geisel School of Medicine, Dartmouth College
| | - Stephen V Mahler
- Department of Neurobiology and Behavior, University of California Irvine
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Hamlett ED, Boger HA, Ledreux A, Kelley CM, Mufson EJ, Falangola MF, Guilfoyle DN, Nixon RA, Patterson D, Duval N, Granholm ACE. Cognitive Impairment, Neuroimaging, and Alzheimer Neuropathology in Mouse Models of Down Syndrome. Curr Alzheimer Res 2016; 13:35-52. [PMID: 26391050 PMCID: PMC5034871 DOI: 10.2174/1567205012666150921095505] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 08/08/2015] [Accepted: 08/20/2015] [Indexed: 11/22/2022]
Abstract
Down syndrome (DS) is the most common non-lethal genetic condition that affects approximately 1 in 700 births in the United States of America. DS is characterized by complete or segmental chromosome 21 trisomy, which leads to variable intellectual disabilities, progressive memory loss, and accelerated neurodegeneration with age. During the last three decades, people with DS have experienced a doubling of life expectancy due to progress in treatment of medical comorbidities, which has allowed this population to reach the age when they develop early onset Alzheimer's disease (AD). Individuals with DS develop cognitive and pathological hallmarks of AD in their fourth or fifth decade, and are currently lacking successful prevention or treatment options for dementia. The profound memory deficits associated with DS-related AD (DS-AD) have been associated with degeneration of several neuronal populations, but mechanisms of neurodegeneration are largely unexplored. The most successful animal model for DS is the Ts65Dn mouse, but several new models have also been developed. In the current review, we discuss recent findings and potential treatment options for the management of memory loss and AD neuropathology in DS mouse models. We also review agerelated neuropathology, and recent findings from neuroimaging studies. The validation of appropriate DS mouse models that mimic neurodegeneration and memory loss in humans with DS can be valuable in the study of novel preventative and treatment interventions, and may be helpful in pinpointing gene-gene interactions as well as specific gene segments involved in neurodegeneration.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Ann-Charlotte E Granholm
- Department Neurosciences, Director, Center on Aging, Medical Univ. South Carolina, Basic Science Bldg, Room 403, 173 Ashley Avenue, Charleston, SC 29425, USA.
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Choong XY, Tosh JL, Pulford LJ, Fisher EMC. Dissecting Alzheimer disease in Down syndrome using mouse models. Front Behav Neurosci 2015; 9:268. [PMID: 26528151 PMCID: PMC4602094 DOI: 10.3389/fnbeh.2015.00268] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 09/21/2015] [Indexed: 11/13/2022] Open
Abstract
Down syndrome (DS) is a common genetic condition caused by the presence of three copies of chromosome 21 (trisomy 21). This greatly increases the risk of Alzheimer disease (AD), but although virtually all people with DS have AD neuropathology by 40 years of age, not all develop dementia. To dissect the genetic contribution of trisomy 21 to DS phenotypes including those relevant to AD, a range of DS mouse models has been generated which are trisomic for chromosome segments syntenic to human chromosome 21. Here, we consider key characteristics of human AD in DS (AD-DS), and our current state of knowledge on related phenotypes in AD and DS mouse models. We go on to review important features needed in future models of AD-DS, to understand this type of dementia and so highlight pathogenic mechanisms relevant to all populations at risk of AD.
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Affiliation(s)
- Xun Yu Choong
- Department of Neurodegenerative Disease, Institute of Neurology, University College London London, UK ; The LonDownS Consortium London, UK
| | - Justin L Tosh
- Department of Neurodegenerative Disease, Institute of Neurology, University College London London, UK ; The LonDownS Consortium London, UK
| | - Laura J Pulford
- Department of Neurodegenerative Disease, Institute of Neurology, University College London London, UK ; The LonDownS Consortium London, UK
| | - Elizabeth M C Fisher
- Department of Neurodegenerative Disease, Institute of Neurology, University College London London, UK ; The LonDownS Consortium London, UK
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Stagni F, Giacomini A, Guidi S, Ciani E, Bartesaghi R. Timing of therapies for Down syndrome: the sooner, the better. Front Behav Neurosci 2015; 9:265. [PMID: 26500515 PMCID: PMC4594009 DOI: 10.3389/fnbeh.2015.00265] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 09/15/2015] [Indexed: 11/13/2022] Open
Abstract
Intellectual disability (ID) is the unavoidable hallmark of Down syndrome (DS), with a heavy impact on public health. Accumulating evidence shows that DS is characterized by numerous neurodevelopmental alterations among which the reduction of neurogenesis, dendritic hypotrophy and connectivity alterations appear to play a particularly prominent role. Although the mechanisms whereby gene triplication impairs brain development in DS have not been fully clarified, it is theoretically possible to correct trisomy-dependent defects with targeted pharmacotherapies. This review summarizes what we know about the effects of pharmacotherapies during different life stages in mouse models of DS. Since brain alterations in DS start to be present prenatally, the prenatal period represents an optimum window of opportunity for therapeutic interventions. Importantly, recent studies clearly show that treatment during the prenatal period can rescue overall brain development and behavior and that this effect outlasts treatment cessation. Although late therapies are unlikely to exert drastic changes in the brain, they may have an impact on the hippocampus, a brain region where neurogenesis continues throughout life. Indeed, treatment at adult life stages improves or even rescues hippocampal neurogenesis and connectivity and hippocampal-dependent learning and memory, although the duration of these effects still remains, in the majority of cases, a matter of investigation. The exciting discovery that trisomy-linked brain abnormalities can be prevented with early interventions gives us reason to believe that treatments during pregnancy may rescue brain development in fetuses with DS. For this reason we deem it extremely important to expedite the discovery of additional therapies practicable in humans in order to identify the best treatment/s in terms of efficacy and paucity of side effects. Prompt achievement of this goal is the big challenge for the scientific community of researchers interested in DS.
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Affiliation(s)
| | | | | | | | - Renata Bartesaghi
- Department of Biomedical and Neuromotor Sciences, University of BolognaBologna, Italy
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