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Westmark PR, Gholston AK, Swietlik TJ, Maganti RK, Westmark CJ. Ketogenic Diet Affects Sleep Architecture in C57BL/6J Wild Type and Fragile X Mice. Int J Mol Sci 2023; 24:14460. [PMID: 37833907 PMCID: PMC10572443 DOI: 10.3390/ijms241914460] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 10/15/2023] Open
Abstract
Nearly half of children with fragile X syndrome experience sleep problems including trouble falling asleep and frequent nighttime awakenings. The goals here were to assess sleep-wake cycles in mice in response to Fmr1 genotype and a dietary intervention that reduces hyperactivity. Electroencephalography (EEG) results were compared with published rest-activity patterns to determine if actigraphy is a viable surrogate for sleep EEG. Specifically, sleep-wake patterns in adult wild type and Fmr1KO littermate mice were recorded after EEG electrode implantation and the recordings manually scored for vigilance states. The data indicated that Fmr1KO mice exhibited sleep-wake patterns similar to wild type littermates when maintained on a control purified ingredient diet. Treatment with a high-fat, low-carbohydrate ketogenic diet increased the percentage of non-rapid eye movement (NREM) sleep in both wild type and Fmr1KO mice during the dark cycle, which corresponded to decreased activity levels. Treatment with a ketogenic diet flattened diurnal sleep periodicity in both wild type and Fmr1KO mice. Differences in several sleep microstructure outcomes (number and length of sleep and wake bouts) supported the altered sleep states in response to a ketogenic diet and were correlated with altered rest-activity cycles. While actigraphy may be a less expensive, reduced labor surrogate for sleep EEG during the dark cycle, daytime resting in mice did not correlate with EEG sleep states.
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Affiliation(s)
- Pamela R. Westmark
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (A.K.G.); (T.J.S.); (R.K.M.)
| | - Aaron K. Gholston
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (A.K.G.); (T.J.S.); (R.K.M.)
- Molecular Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, USA
| | - Timothy J. Swietlik
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (A.K.G.); (T.J.S.); (R.K.M.)
| | - Rama K. Maganti
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (A.K.G.); (T.J.S.); (R.K.M.)
| | - Cara J. Westmark
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (A.K.G.); (T.J.S.); (R.K.M.)
- Molecular Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, USA
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2
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D’Elia A, Schiavi S, Manduca A, Rava A, Buzzelli V, Ascone F, Orsini T, Putti S, Soluri A, Galli F, Soluri A, Mattei M, Cicconi R, Massari R, Trezza V. FMR1 deletion in rats induces hyperactivity with no changes in striatal dopamine transporter availability. Sci Rep 2022; 12:22535. [PMID: 36581671 PMCID: PMC9800572 DOI: 10.1038/s41598-022-26986-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 12/22/2022] [Indexed: 12/30/2022] Open
Abstract
Autism Spectrum Disorder (ASD) is a pervasive neurodevelopmental disorder emerging in early life characterized by impairments in social interaction, poor verbal and non-verbal communication, and repetitive patterns of behaviors. Among the best-known genetic risk factors for ASD, there are mutations causing the loss of the Fragile X Messenger Ribonucleoprotein 1 (FMRP) leading to Fragile X syndrome (FXS), a common form of inherited intellectual disability and the leading monogenic cause of ASD. Being a pivotal regulator of motor activity, motivation, attention, and reward processing, dopaminergic neurotransmission has a key role in several neuropsychiatric disorders, including ASD. Fmr1 Δexon 8 rats have been validated as a genetic model of ASD based on FMR1 deletion, and they are also a rat model of FXS. Here, we performed behavioral, biochemical and in vivo SPECT neuroimaging experiments to investigate whether Fmr1 Δexon 8 rats display ASD-like repetitive behaviors associated with changes in striatal dopamine transporter (DAT) availability assessed through in vivo SPECT neuroimaging. At the behavioral level, Fmr1 Δexon 8 rats displayed hyperactivity in the open field test in the absence of repetitive behaviors in the hole board test. However, these behavioral alterations were not associated with changes in striatal DAT availability as assessed by non-invasive in vivo SPECT and Western blot analyses.
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Affiliation(s)
- Annunziata D’Elia
- grid.5326.20000 0001 1940 4177Institute of Biochemistry and Cell Biology (IBBC), National Research Council of Italy (CNR), c/o International Campus “A. Buzzati-Traverso”, Via E. Ramarini, 32, 00015 Monterotondo Scalo (Rome), Italy ,grid.8509.40000000121622106Department of Science, Section of Biomedical Sciences and Technologies, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
| | - Sara Schiavi
- grid.8509.40000000121622106Department of Science, Section of Biomedical Sciences and Technologies, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
| | - Antonia Manduca
- grid.8509.40000000121622106Department of Science, Section of Biomedical Sciences and Technologies, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy ,grid.417778.a0000 0001 0692 3437Neuroendocrinology, Metabolism and Neuropharmacology Unit, IRCSS Fondazione Santa Lucia, Rome, Italy
| | - Alessandro Rava
- grid.8509.40000000121622106Department of Science, Section of Biomedical Sciences and Technologies, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
| | - Valeria Buzzelli
- grid.8509.40000000121622106Department of Science, Section of Biomedical Sciences and Technologies, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
| | - Fabrizio Ascone
- grid.8509.40000000121622106Department of Science, Section of Biomedical Sciences and Technologies, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
| | - Tiziana Orsini
- grid.5326.20000 0001 1940 4177Institute of Biochemistry and Cell Biology (IBBC), National Research Council of Italy (CNR), c/o International Campus “A. Buzzati-Traverso”, Via E. Ramarini, 32, 00015 Monterotondo Scalo (Rome), Italy
| | - Sabrina Putti
- grid.5326.20000 0001 1940 4177Institute of Biochemistry and Cell Biology (IBBC), National Research Council of Italy (CNR), c/o International Campus “A. Buzzati-Traverso”, Via E. Ramarini, 32, 00015 Monterotondo Scalo (Rome), Italy
| | - Andrea Soluri
- grid.5326.20000 0001 1940 4177Institute of Biochemistry and Cell Biology (IBBC), National Research Council of Italy (CNR), c/o International Campus “A. Buzzati-Traverso”, Via E. Ramarini, 32, 00015 Monterotondo Scalo (Rome), Italy ,grid.9657.d0000 0004 1757 5329Unit of Molecular Neurosciences, University Campus Bio-Medico, Rome, Rome, Italy
| | - Filippo Galli
- grid.7841.aNuclear Medicine Unit, Department of Medical-Surgical Sciences and of Translational Medicine, Faculty of Medicine and Psychology, “Sapienza” University of Rome, Rome, Italy
| | - Alessandro Soluri
- grid.5326.20000 0001 1940 4177Institute of Biochemistry and Cell Biology (IBBC), National Research Council of Italy (CNR), c/o International Campus “A. Buzzati-Traverso”, Via E. Ramarini, 32, 00015 Monterotondo Scalo (Rome), Italy
| | - Maurizio Mattei
- grid.6530.00000 0001 2300 0941Department of Biology and Centro di Servizi Interdipartimentale-Stazione per la Tecnologia Animale, “Tor Vergata” University, Rome, Italy
| | - Rosella Cicconi
- grid.6530.00000 0001 2300 0941Department of Biology and Centro di Servizi Interdipartimentale-Stazione per la Tecnologia Animale, “Tor Vergata” University, Rome, Italy
| | - Roberto Massari
- grid.5326.20000 0001 1940 4177Institute of Biochemistry and Cell Biology (IBBC), National Research Council of Italy (CNR), c/o International Campus “A. Buzzati-Traverso”, Via E. Ramarini, 32, 00015 Monterotondo Scalo (Rome), Italy
| | - Viviana Trezza
- grid.8509.40000000121622106Department of Science, Section of Biomedical Sciences and Technologies, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
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3
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Gioia R, Seri T, Diamanti T, Fimmanò S, Vitale M, Ahlenius H, Kokaia Z, Tirone F, Micheli L, Biagioni S, Lupo G, Rinaldi A, De Jaco A, Cacci E. Adult hippocampal neurogenesis and social behavioural deficits in the R451C Neuroligin3 mouse model of autism are reverted by the antidepressant fluoxetine. J Neurochem 2022; 165:318-333. [PMID: 36583243 DOI: 10.1111/jnc.15753] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 12/07/2022] [Accepted: 12/16/2022] [Indexed: 12/31/2022]
Abstract
Neuron generation persists throughout life in the hippocampus but is altered in animal models of neurological and neuropsychiatric diseases, suggesting that disease-associated decline in cognitive and emotional hippocampal-dependent behaviours might be functionally linked with dysregulation of postnatal neurogenesis. Depletion of the adult neural stem/progenitor cell (NSPCs) pool and neurogenic decline have been recently described in mice expressing synaptic susceptibility genes associated with autism spectrum disorder (ASDs). To gain further insight into mechanisms regulating neurogenesis in mice carrying mutations in synaptic genes related to monogenic ASDs, we used the R451C Neuroligin3 knock-in (Nlgn3 KI) mouse, which is characterized by structural brain abnormalities, deficits in synaptic functions and reduced sociability. We show that the number of adult-born neurons, but not the size of the NSPC pool, was reduced in the ventral dentate gyrus in knock-in mice. Notably, this neurogenic decline was rescued by daily injecting mice with 10 mg/Kg of the antidepressant fluoxetine for 20 consecutive days. Sustained treatment also improved KI mice's sociability and increased the number of c-Fos active adult-born neurons, compared with vehicle-injected KI mice. Our study uncovers neurogenesis-mediated alterations in the brain of R451C KI mouse, showing that the R451C Nlgn3 mutation leads to lasting, albeit pharmacologically reversible, changes in the brain, affecting neuron formation in the adult hippocampus. Our results suggest that fluoxetine can ameliorate social behaviour in KI mice, at least in part, by rescuing adult hippocampal neurogenesis, which may be relevant for the pharmacological treatment of ASDs.
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Affiliation(s)
- Roberta Gioia
- Department of Biology and Biotechnology "Charles Darwin", Sapienza, University of Rome, Rome, Italy
| | - Tommaso Seri
- Department of Biology and Biotechnology "Charles Darwin", Sapienza, University of Rome, Rome, Italy
- PhD program in Behavioral Neuroscience, Sapienza University of Rome, Rome, Italy
| | - Tamara Diamanti
- Department of Biology and Biotechnology "Charles Darwin", Sapienza, University of Rome, Rome, Italy
| | - Stefania Fimmanò
- Department of Biology and Biotechnology "Charles Darwin", Sapienza, University of Rome, Rome, Italy
| | - Marina Vitale
- Department of Biology and Biotechnology "Charles Darwin", Sapienza, University of Rome, Rome, Italy
| | - Henrik Ahlenius
- Faculty of Medicine, Department of Clinical Sciences Lund, Neurology, Stem Cells, Aging and Neurodegeneration, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund, Sweden
| | - Zaal Kokaia
- Lund Stem Cell Center, Department of Clinical Sciences, Lund University Hospital, Lund, Sweden
| | - Felice Tirone
- Institute of Biochemistry and Cell Biology, National Research Council, Rome, Italy
| | - Laura Micheli
- Institute of Biochemistry and Cell Biology, National Research Council, Rome, Italy
| | - Stefano Biagioni
- Department of Biology and Biotechnology "Charles Darwin", Sapienza, University of Rome, Rome, Italy
| | - Giuseppe Lupo
- Department of Biology and Biotechnology "Charles Darwin", Sapienza, University of Rome, Rome, Italy
| | - Arianna Rinaldi
- Department of Biology and Biotechnology "Charles Darwin", Sapienza, University of Rome, Rome, Italy
- Centre for Research in Neurobiology "D. Bovet", Sapienza University of Rome, Rome, Italy
| | - Antonella De Jaco
- Department of Biology and Biotechnology "Charles Darwin", Sapienza, University of Rome, Rome, Italy
- Centre for Research in Neurobiology "D. Bovet", Sapienza University of Rome, Rome, Italy
| | - Emanuele Cacci
- Department of Biology and Biotechnology "Charles Darwin", Sapienza, University of Rome, Rome, Italy
- Centre for Research in Neurobiology "D. Bovet", Sapienza University of Rome, Rome, Italy
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4
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Walsh JJ, Llorach P, Cardozo Pinto DF, Wenderski W, Christoffel DJ, Salgado JS, Heifets BD, Crabtree GR, Malenka RC. Systemic enhancement of serotonin signaling reverses social deficits in multiple mouse models for ASD. Neuropsychopharmacology 2021; 46:2000-2010. [PMID: 34239048 PMCID: PMC8429585 DOI: 10.1038/s41386-021-01091-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 02/06/2023]
Abstract
Autism spectrum disorder (ASD) is a common set of heterogeneous neurodevelopmental disorders resulting from a variety of genetic and environmental risk factors. A core feature of ASD is impairment in prosocial interactions. Current treatment options for individuals diagnosed with ASD are limited, with no current FDA-approved medications that effectively treat its core symptoms. We recently demonstrated that enhanced serotonin (5-HT) activity in the nucleus accumbens (NAc), via optogenetic activation of 5-HTergic inputs or direct infusion of a specific 5-HT1b receptor agonist, reverses social deficits in a genetic mouse model for ASD based on 16p11.2 copy number variation. Furthermore, the recreational drug MDMA, which is currently being evaluated in clinical trials, promotes sociability in mice due to its 5-HT releasing properties in the NAc. Here, we systematically evaluated the ability of MDMA and a selective 5-HT1b receptor agonist to rescue sociability deficits in multiple different mouse models for ASD. We find that MDMA administration enhances sociability in control mice and reverses sociability deficits in all four ASD mouse models examined, whereas administration of a 5-HT1b receptor agonist selectively rescued the sociability deficits in all six mouse models for ASD. These preclinical findings suggest that pharmacological enhancement of 5-HT release or direct 5-HT1b receptor activation may be therapeutically efficacious in ameliorating some of the core sociability deficits present across etiologically distinct presentations of ASD.
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Affiliation(s)
- Jessica J Walsh
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Pierre Llorach
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Daniel F Cardozo Pinto
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Wendy Wenderski
- Department of Pathology, Stanford Medical School, Stanford, CA, USA
- Department of Genetics, Stanford Medical School, Stanford, CA, USA
- Department of Developmental Biology, Stanford Medical School, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Daniel J Christoffel
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Juliana S Salgado
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Boris D Heifets
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Gerald R Crabtree
- Department of Pathology, Stanford Medical School, Stanford, CA, USA
- Department of Genetics, Stanford Medical School, Stanford, CA, USA
- Department of Developmental Biology, Stanford Medical School, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Robert C Malenka
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA.
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5
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Heaney CF, Namjoshi SV, Uneri A, Bach EC, Weiner JL, Raab-Graham KF. Role of FMRP in rapid antidepressant effects and synapse regulation. Mol Psychiatry 2021; 26:2350-2362. [PMID: 33432187 PMCID: PMC8440195 DOI: 10.1038/s41380-020-00977-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 11/23/2020] [Accepted: 12/01/2020] [Indexed: 11/09/2022]
Abstract
Rapid antidepressants are novel treatments for major depressive disorder (MDD) and work by blocking N-methyl-D-aspartate receptors (NMDARs), which, in turn, activate the protein synthesis pathway regulated by mechanistic/mammalian target of rapamycin complex 1 (mTORC1). Our recent work demonstrates that the RNA-binding protein Fragile X Mental Retardation Protein (FMRP) is downregulated in dendrites upon treatment with a rapid antidepressant. Here, we show that the behavioral effects of the rapid antidepressant Ro-25-6981 require FMRP expression, and treatment promotes differential mRNA binding to FMRP in an mTORC1-dependent manner. Further, these mRNAs are identified to regulate transsynaptic signaling. Using a novel technique, we show that synapse formation underlying the behavioral effects of Ro-25-6981 requires GABABR-mediated mTORC1 activity in WT animals. Finally, we demonstrate that in an animal model that lacks FMRP expression and has clinical relevance for Fragile X Syndrome (FXS), GABABR activity is detrimental to the effects of Ro-25-6981. These effects are rescued with the combined therapy of blocking GABABRs and NMDARs, indicating that rapid antidepressants alone may not be an effective treatment for people with comorbid FXS and MDD.
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Affiliation(s)
- Chelcie F Heaney
- Department of Physiology and Pharmacology, Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
- Wake Forest Translational Alcohol Research Center (WF-TARC), Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Sanjeev V Namjoshi
- Department of Physiology and Pharmacology, Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Ayse Uneri
- Department of Physiology and Pharmacology, Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Eva C Bach
- Department of Physiology and Pharmacology, Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
- Wake Forest Translational Alcohol Research Center (WF-TARC), Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Jeffrey L Weiner
- Department of Physiology and Pharmacology, Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
- Wake Forest Translational Alcohol Research Center (WF-TARC), Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Kimberly F Raab-Graham
- Department of Physiology and Pharmacology, Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA.
- Wake Forest Translational Alcohol Research Center (WF-TARC), Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA.
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6
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Luo OD, Kwiecien-Delaney B, Martin P, Foster JA, Sidor MM. The effect of early life immune challenge on adult forced swim test performance and hippocampal neurogenesis. J Neuroimmunol 2021; 354:577530. [PMID: 33744708 DOI: 10.1016/j.jneuroim.2021.577530] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 02/22/2021] [Accepted: 02/22/2021] [Indexed: 10/22/2022]
Abstract
Many psychiatric diseases can be considered neurodevelopmental in nature and accumulating evidence links immune system dysfunction to disease etiology. Yet, it is currently unknown how the immune system alters brain function through development to increase susceptibility to psychiatric illness. Neonatal immune challenge in rodents is a neurodevelopmental model that has been associated with long-term molecular and behavioural changes in stress-reactivity. As enhanced stress-reactivity is associated with the emergence of depressive-like behaviours concurrent with hippocampal pathology, we measured depressive-like behaviour in the forced swim test and hippocampal neurogenesis in adult mice neonatally exposed to lipopolysaccharide LPS; 0.05 mg/kg, i.p. on postnatal days 3 and 5. As there are important functional differences along the ventral-dorsal hippocampus axis, ventral and dorsal hippocampal neurogenesis were measured separately. Our findings reveal a sexually-dimorphic response to early-life LPS challenge. Male LPS-mice spent less time immobile in the forced swim test, suggesting altered reactivity to swim stress. This was accompanied by an increase in doublecortin-positive cells in the dorsal hippocampus of female mice. These findings demonstrate that exposure to an immune challenge during critical developmental time periods leads to long-term sexually-dimorphic alterations in stress-reactivity that are accompanied by changes to adult hippocampal neurogenesis.
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Affiliation(s)
- Owen D Luo
- Psychiatry and Behavioural Neuroscience, McMaster University, Hamilton, Ontario, Canada
| | | | - Patrick Martin
- Psychiatry and Behavioural Neuroscience, McMaster University, Hamilton, Ontario, Canada
| | - Jane A Foster
- Psychiatry and Behavioural Neuroscience, McMaster University, Hamilton, Ontario, Canada; Department of Psychiatry, St. Michael's Hospital, Toronto, Ontario, Canada.
| | - Michelle M Sidor
- Psychiatry and Behavioural Neuroscience, McMaster University, Hamilton, Ontario, Canada
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7
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Quinlan MA, Robson MJ, Ye R, Rose KL, Schey KL, Blakely RD. Ex vivo Quantitative Proteomic Analysis of Serotonin Transporter Interactome: Network Impact of the SERT Ala56 Coding Variant. Front Mol Neurosci 2020; 13:89. [PMID: 32581705 PMCID: PMC7295033 DOI: 10.3389/fnmol.2020.00089] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 04/28/2020] [Indexed: 12/15/2022] Open
Abstract
Altered serotonin (5-HT) signaling is associated with multiple brain disorders, including major depressive disorder (MDD), obsessive-compulsive disorder (OCD), and autism spectrum disorder (ASD). The presynaptic, high-affinity 5-HT transporter (SERT) tightly regulates 5-HT clearance after release from serotonergic neurons in the brain and enteric nervous systems, among other sites. Accumulating evidence suggests that SERT is dynamically regulated in distinct activity states as a result of environmental and intracellular stimuli, with regulation perturbed by disease-associated coding variants. Our lab identified a rare, hypermorphic SERT coding substitution, Gly56Ala, in subjects with ASD, finding that the Ala56 variant stabilizes a high-affinity outward-facing conformation (SERT∗) that leads to elevated 5-HT uptake in vitro and in vivo. Hyperactive SERT Ala56 appears to preclude further activity enhancements by p38α mitogen-activated protein kinase (MAPK) and can be normalized by pharmacological p38α MAPK inhibition, consistent with SERT Ala56 mimicking, constitutively, a high-activity conformation entered into transiently by p38α MAPK activation. We hypothesize that changes in SERT-interacting proteins (SIPs) support the shift of SERT into the SERT∗ state which may be captured by comparing the composition of SERT Ala56 protein complexes with those of wildtype (WT) SERT, defining specific interactions through comparisons of protein complexes recovered using preparations from SERT–/– (knockout; KO) mice. Using quantitative proteomic-based approaches, we identify a total of 459 SIPs, that demonstrate both SERT specificity and sensitivity to the Gly56Ala substitution, with a striking bias being a loss of SIP interactions with SERT Ala56 compared to WT SERT. Among this group are previously validated SIPs, such as flotillin-1 (FLOT1) and protein phosphatase 2A (PP2A), whose functions are believed to contribute to SERT microdomain localization and regulation. Interestingly, our studies nominate a number of novel SIPs implicated in ASD, including fragile X mental retardation 1 protein (FMR1) and SH3 and multiple ankyrin repeat domains protein 3 (SHANK3), of potential relevance to long-standing evidence of serotonergic contributions to ASD. Further investigation of these SIPs, and the broader networks they engage, may afford a greater understanding of ASD as well as other brain and peripheral disorders associated with perturbed 5-HT signaling.
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Affiliation(s)
- Meagan A Quinlan
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, United States.,Department of Pharmacology, Vanderbilt University, Nashville, TN, United States.,Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL, United States
| | - Matthew J Robson
- Division of Pharmaceutical Sciences, James L. Winkle College of Pharmacy, University of Cincinnati, Cincinnati, OH, United States
| | - Ran Ye
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States
| | - Kristie L Rose
- Department of Biochemistry, Vanderbilt University, Nashville, TN, United States
| | - Kevin L Schey
- Department of Biochemistry, Vanderbilt University, Nashville, TN, United States
| | - Randy D Blakely
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States.,Brain Institute, Florida Atlantic University, Jupiter, FL, United States
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8
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Increased DNA Damage and Apoptosis in CDKL5-Deficient Neurons. Mol Neurobiol 2020; 57:2244-2262. [PMID: 32002787 DOI: 10.1007/s12035-020-01884-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 01/20/2020] [Indexed: 12/15/2022]
Abstract
Mutations in the CDKL5 gene, which encodes a serine/threonine kinase, causes a rare encephalopathy, characterized by early-onset epilepsy and severe intellectual disability, named CDKL5 deficiency disorder (CDD). In vitro and in vivo studies in mouse models of Cdkl5 deficiency have highlighted the role of CDKL5 in brain development and, in particular, in the morphogenesis and synaptic connectivity of hippocampal and cortical neurons. Interestingly, Cdkl5 deficiency in mice increases vulnerability to excitotoxic stress in hippocampal neurons. However, the mechanism by which CDKL5 controls neuronal survival is far from being understood. To investigate further the function of CDKL5 and dissect the molecular mechanisms underlying neuronal survival, we generated a human neuronal model of CDKL5 deficiency, using CRISPR/Cas9-mediated genome editing. We demonstrated that CDKL5 deletion in human neuroblastoma SH-SY5Y cells not only impairs neuronal maturation but also reduces cell proliferation and survival, with alterations in the AKT and ERK signaling pathways and an increase in the proapoptotic BAX protein and in DNA damage-associated biomarkers (i.e., γH2AX, RAD50, and PARP1). Furthermore, CDKL5-deficient cells were hypersensitive to DNA damage-associated stress, accumulated more DNA damage foci (γH2AX positive) and were more prone to cell death than the controls. Importantly, increased kainic acid-induced cell death of hippocampal neurons of Cdkl5 KO mice correlated with an increased γH2AX immunostaining. The results suggest a previously unknown role for CDKL5 in DNA damage response that could underlie the pro-survival function of CDKL5.
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9
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Fuchs C, Gennaccaro L, Ren E, Galvani G, Trazzi S, Medici G, Loi M, Conway E, Devinsky O, Rimondini R, Ciani E. Pharmacotherapy with sertraline rescues brain development and behavior in a mouse model of CDKL5 deficiency disorder. Neuropharmacology 2019; 167:107746. [PMID: 31469994 DOI: 10.1016/j.neuropharm.2019.107746] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/27/2019] [Accepted: 08/21/2019] [Indexed: 12/15/2022]
Abstract
Mutations in the X-linked cyclin-dependent kinase-like 5 (CDKL5) gene cause a severe neurodevelopmental disorder, CDKL5 deficiency disorder (CDD). CDKL5 is fundamental for correct brain development and function, but the molecular mechanisms underlying aberrant neurologic dysfunction in CDD are incompletely understood. Here we show a dysregulation of hippocampal and cortical serotonergic (5-HT) receptor expression in heterozygous Cdkl5 knockout (KO) female mice, suggesting that impaired 5-HT neurotransmission contributes to CDD. We demonstrate that targeting impaired 5-HT signaling via the selective serotonin reuptake inhibitor (SSRI) sertraline rescues CDD-related neurodevelopmental and behavioral defects in heterozygous Cdkl5 KO female mice. In particular, chronic treatment with sertraline normalized locomotion, stereotypic and autistic-like features, and spatial memory in Cdkl5 KO mice. These positive behavioral effects were accompanied by restored neuronal survival, dendritic development and synaptic connectivity. At a molecular level, sertraline increased brain-derived neurotrophic factor (BDNF) expression and restored abnormal phosphorylation levels of tyrosine kinase B (TrkB) and its downstream target the extracellular signal-regulated kinase (ERK1/2). Since sertraline is an FDA-approved drug with an extensive safety and tolerability data package, even for children, our findings suggest that sertraline may improve neurodevelopment in children with CDD. This article is part of the special issue entitled 'Serotonin Research: Crossing Scales and Boundaries'.
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Affiliation(s)
- Claudia Fuchs
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy.
| | - Laura Gennaccaro
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy
| | - Elisa Ren
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy
| | - Giuseppe Galvani
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy
| | - Stefania Trazzi
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy
| | - Giorgio Medici
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy
| | - Manuela Loi
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy
| | - Erin Conway
- Department of Neurology, NYU Langone Health, New York, USA
| | - Orrin Devinsky
- Department of Neurology, NYU Langone Health, New York, USA
| | - Roberto Rimondini
- Department of Medical and Clinical Sciences, University of Bologna, Italy
| | - Elisabetta Ciani
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy.
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Telias M. Molecular Mechanisms of Synaptic Dysregulation in Fragile X Syndrome and Autism Spectrum Disorders. Front Mol Neurosci 2019; 12:51. [PMID: 30899214 PMCID: PMC6417395 DOI: 10.3389/fnmol.2019.00051] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 02/12/2019] [Indexed: 12/21/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common form of monogenic hereditary cognitive impairment. FXS patient exhibit a high comorbidity rate with autism spectrum disorders (ASDs). This makes FXS a model disease for understanding how synaptic dysregulation alters neuronal excitability, learning and memory, social behavior, and more. Since 1991, with the discovery of fragile X mental retardation 1 (FMR1) as the sole gene that is mutated in FXS, thousands of studies into the function of the gene and its encoded protein FMR1 protein (FMRP), have been conducted, yielding important information regarding the pathophysiology of the disease, as well as insight into basic synaptic mechanisms that control neuronal networking and circuitry. Among the most important, are molecular mechanisms directly involved in plasticity, including glutamate and γ-aminobutyric acid (GABA) receptors, which can control synaptic transmission and signal transduction, including short- and long-term plasticity. More recently, several novel mechanisms involving growth factors, enzymatic cascades and transcription factors (TFs), have been proposed to have the potential of explaining some of the synaptic dysregulation in FXS. In this review article, I summarize the main mechanisms proposed to underlie synaptic disruption in FXS and ASDs. I focus on studies conducted on the Fmr1 knock-out (KO) mouse model and on FXS-human pluripotent stem cells (hPSCs), emphasizing the differences and even contradictions between mouse and human, whenever possible. As FXS and ASDs are both neurodevelopmental disorders that follow a specific time-course of disease progression, I highlight those studies focusing on the differential developmental regulation of synaptic abnormalities in these diseases.
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Affiliation(s)
- Michael Telias
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
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Angelakos CC, Tudor JC, Ferri SL, Jongens TA, Abel T. Home-cage hypoactivity in mouse genetic models of autism spectrum disorder. Neurobiol Learn Mem 2019; 165:107000. [PMID: 30797034 DOI: 10.1016/j.nlm.2019.02.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 11/28/2018] [Accepted: 02/19/2019] [Indexed: 11/16/2022]
Abstract
Genome-wide association and whole exome sequencing studies from Autism Spectrum Disorder (ASD) patient populations have implicated numerous risk factor genes whose mutation or deletion results in significantly increased incidence of ASD. Behavioral studies of monogenic mutant mouse models of ASD-associated genes have been useful for identifying aberrant neural circuitry. However, behavioral results often differ from lab to lab, and studies incorporating both males and females are often not performed despite the significant sex-bias of ASD. In this study, we sought to investigate the simple, passive behavior of home-cage activity monitoring across multiple 24-h days in four different monogenic mouse models of ASD: Shank3b-/-, Cntnap2-/-, Pcdh10+/-, and Fmr1 knockout mice. Relative to sex-matched wildtype (WT) littermates, we discovered significant home-cage hypoactivity, particularly in the dark (active) phase of the light/dark cycle, in male mice of all four ASD-associated transgenic models. For Cntnap2-/- and Pcdh10+/- mice, these activity alterations were sex-specific, as female mice did not exhibit home-cage activity differences relative to sex-matched WT controls. These home-cage hypoactivity alterations differ from activity findings previously reported using short-term activity measurements in a novel open field. Despite circadian problems reported in human ASD patients, none of the mouse models studied had alterations in free-running circadian period. Together, these findings highlight a shared phenotype across several monogenic mouse models of ASD, outline the importance of methodology on behavioral interpretation, and in some genetic lines parallel the male-enhanced phenotypic presentation observed in human ASDs.
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Affiliation(s)
- Christopher C Angelakos
- Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Jennifer C Tudor
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, United States; Department of Biology, Saint Joseph's University, Philadelphia, PA 19131, United States
| | - Sarah L Ferri
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, United States; Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, United States
| | - Thomas A Jongens
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Ted Abel
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, United States; Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, United States.
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Danesi C, Achuta VS, Corcoran P, Peteri UK, Turconi G, Matsui N, Albayrak I, Rezov V, Isaksson A, Castrén ML. Increased Calcium Influx through L-type Calcium Channels in Human and Mouse Neural Progenitors Lacking Fragile X Mental Retardation Protein. Stem Cell Reports 2018; 11:1449-1461. [PMID: 30503263 PMCID: PMC6294261 DOI: 10.1016/j.stemcr.2018.11.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 11/02/2018] [Accepted: 11/05/2018] [Indexed: 02/07/2023] Open
Abstract
The absence of FMR1 protein (FMRP) causes fragile X syndrome (FXS) and disturbed FMRP function is implicated in several forms of human psychopathology. We show that intracellular calcium responses to depolarization are augmented in neural progenitors derived from human induced pluripotent stem cells and mouse brain with FXS. Increased calcium influx via nifedipine-sensitive voltage-gated calcium (Cav) channels contributes to the exaggerated responses to depolarization and type 1 metabotropic glutamate receptor activation. The ratio of L-type/T-type Cav channel expression is increased in FXS progenitors and correlates with enhanced progenitor differentiation to glutamate-responsive cells. Genetic reduction of brain-derived neurotrophic factor in FXS mouse progenitors diminishes the expression of Cav channels and activity-dependent responses, which are associated with increased phosphorylation of the phospholipase C-γ1 site within TrkB receptors and changes of differentiating progenitor subpopulations. Our results show developmental effects of increased calcium influx via L-type Cav channels in FXS neural progenitors. Responses to activity are augmented in neural progenitors in fragile X syndrome (FXS). Increased Ca2+ influx contributes to the exaggerated FXS progenitor responses L-type voltage-gated channels are abnormally activated in FXS progenitors Reduced BDNF diminishes Ca2+ influx and modulates FXS progenitor differentiation
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Affiliation(s)
- Claudia Danesi
- Faculty of Medicine, Physiology, University of Helsinki, PO Box 63, FIN-00014 University of Helsinki, Helsinki, Finland
| | - Venkat Swaroop Achuta
- Faculty of Medicine, Physiology, University of Helsinki, PO Box 63, FIN-00014 University of Helsinki, Helsinki, Finland
| | - Padraic Corcoran
- Array and Analysis Facility, Department of Medical Sciences, Uppsala University, PO Box 3056, 75003 Uppsala, Sweden
| | - Ulla-Kaisa Peteri
- Faculty of Medicine, Physiology, University of Helsinki, PO Box 63, FIN-00014 University of Helsinki, Helsinki, Finland
| | - Giorgio Turconi
- Faculty of Medicine, Physiology, University of Helsinki, PO Box 63, FIN-00014 University of Helsinki, Helsinki, Finland
| | - Nobuaki Matsui
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, 770-8514, Japan
| | - Ilyas Albayrak
- Faculty of Medicine, Physiology, University of Helsinki, PO Box 63, FIN-00014 University of Helsinki, Helsinki, Finland
| | - Veronika Rezov
- Faculty of Medicine, Physiology, University of Helsinki, PO Box 63, FIN-00014 University of Helsinki, Helsinki, Finland
| | - Anders Isaksson
- Array and Analysis Facility, Department of Medical Sciences, Uppsala University, PO Box 3056, 75003 Uppsala, Sweden
| | - Maija L Castrén
- Faculty of Medicine, Physiology, University of Helsinki, PO Box 63, FIN-00014 University of Helsinki, Helsinki, Finland.
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Melancia F, Trezza V. Modelling fragile X syndrome in the laboratory setting: A behavioral perspective. Behav Brain Res 2018; 350:149-163. [DOI: 10.1016/j.bbr.2018.04.042] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 04/24/2018] [Accepted: 04/24/2018] [Indexed: 12/13/2022]
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Panzini CM, Ehlinger DG, Alchahin AM, Guo Y, Commons KG. 16p11.2 deletion syndrome mice perseverate with active coping response to acute stress - rescue by blocking 5-HT2A receptors. J Neurochem 2017; 143:708-721. [PMID: 28948999 PMCID: PMC5729115 DOI: 10.1111/jnc.14227] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 09/11/2017] [Accepted: 09/18/2017] [Indexed: 12/31/2022]
Abstract
In humans a chromosomal hemideletion of the 16p11.2 region results in variable neurodevelopmental deficits including developmental delay, intellectual disability, and features of autism spectrum disorder (ASD). Serotonin is implicated in ASD but its role remains enigmatic. In this study we sought to determine if and how abnormalities in serotonin neurotransmission could contribute to the behavioral phenotype of the 16p11.2 deletion syndrome in a mouse model (Del mouse). As ASD is frequently associated with altered response to acute stress and stress may exacerbate repetitive behavior in ASD, we studied the Del mouse behavior in the context of an acute stress using the forced swim test, a paradigm well characterized with respect to serotonin. Del mice perseverated with active coping (swimming) in the forced swim test and failed to adopt passive coping strategies with time as did their wild-type littermates. Analysis of monoamine content by HPLC provided evidence for altered endogenous serotonin neurotransmission in Del mice while there was no effect of genotype on any other monoamine. Moreover, we found that Del mice were highly sensitive to the 5-HT2A antagonists M100907, which at a dose of 0.1 mg/kg normalized their level of active coping and restored the gradual shift to passive coping in the forced swim test. Supporting evidence for altered endogenous serotonin signaling was provided by observations of additional ligand effects including altered forebrain Fos expression. Taken together, these observations indicate notable changes in endogenous serotonin signaling in 16p11.2 deletion mice and support the therapeutic utility of 5-HT2A receptor antagonists.
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Affiliation(s)
- Chris M Panzini
- Department of Anesthesiology, Perioperative, and Pain Medicine, Boston Children's Hospital and Department of Anaesthesia, Harvard Medical School, Boston, Massachusetts, USA
| | - Daniel G Ehlinger
- Department of Anesthesiology, Perioperative, and Pain Medicine, Boston Children's Hospital and Department of Anaesthesia, Harvard Medical School, Boston, Massachusetts, USA
| | - Adele M Alchahin
- Department of Anesthesiology, Perioperative, and Pain Medicine, Boston Children's Hospital and Department of Anaesthesia, Harvard Medical School, Boston, Massachusetts, USA
| | - Yueping Guo
- Department of Anesthesiology, Perioperative, and Pain Medicine, Boston Children's Hospital and Department of Anaesthesia, Harvard Medical School, Boston, Massachusetts, USA
- Department of Anesthesiology, Second Affiliated Hospital, Harbin Med. University, Harbin, China
| | - Kathryn G Commons
- Department of Anesthesiology, Perioperative, and Pain Medicine, Boston Children's Hospital and Department of Anaesthesia, Harvard Medical School, Boston, Massachusetts, USA
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Delayed Maturation of Fast-Spiking Interneurons Is Rectified by Activation of the TrkB Receptor in the Mouse Model of Fragile X Syndrome. J Neurosci 2017; 37:11298-11310. [PMID: 29038238 DOI: 10.1523/jneurosci.2893-16.2017] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 09/27/2017] [Accepted: 10/03/2017] [Indexed: 11/21/2022] Open
Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder that is a leading cause of inherited intellectual disability, and the most common known cause of autism spectrum disorder. FXS is broadly characterized by sensory hypersensitivity and several developmental alterations in synaptic and circuit function have been uncovered in the sensory cortex of the mouse model of FXS (Fmr1 KO). GABA-mediated neurotransmission and fast-spiking (FS) GABAergic interneurons are central to cortical circuit development in the neonate. Here we demonstrate that there is a delay in the maturation of the intrinsic properties of FS interneurons in the sensory cortex, and a deficit in the formation of excitatory synaptic inputs on to these neurons in neonatal Fmr1 KO mice. Both these delays in neuronal and synaptic maturation were rectified by chronic administration of a TrkB receptor agonist. These results demonstrate that the maturation of the GABAergic circuit in the sensory cortex is altered during a critical developmental period due in part to a perturbation in BDNF-TrkB signaling, and could contribute to the alterations in cortical development underlying the sensory pathophysiology of FXS.SIGNIFICANCE STATEMENT Fragile X (FXS) individuals have a range of sensory related phenotypes, and there is growing evidence of alterations in neuronal circuits in the sensory cortex of the mouse model of FXS (Fmr1 KO). GABAergic interneurons are central to the correct formation of circuits during cortical critical periods. Here we demonstrate a delay in the maturation of the properties and synaptic connectivity of interneurons in Fmr1 KO mice during a critical period of cortical development. The delays both in cellular and synaptic maturation were rectified by administration of a TrkB receptor agonist, suggesting reduced BDNF-TrkB signaling as a contributing factor. These results provide evidence that the function of fast-spiking interneurons is disrupted due to a deficiency in neurotrophin signaling during early development in FXS.
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16
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Ehlinger DG, Commons KG. Altered Cav1.2 function in the Timothy syndrome mouse model produces ascending serotonergic abnormalities. Eur J Neurosci 2017; 46:2416-2425. [PMID: 28921675 DOI: 10.1111/ejn.13707] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 08/05/2017] [Accepted: 08/23/2017] [Indexed: 01/17/2023]
Abstract
Polymorphism in the gene CACNA1C, encoding the pore-forming subunit of Cav1.2 L-type calcium channels, has one of the strongest genetic linkages to schizophrenia, bipolar disorder and major depressive disorder: psychopathologies in which serotonin signaling has been implicated. Additionally, a gain-of-function mutation in CACNA1C is responsible for the neurodevelopmental disorder Timothy syndrome that presents with prominent behavioral features on the autism spectrum. Given an emerging role for serotonin in the etiology of autism spectrum disorders (ASD), we investigate the relationship between Cav1.2 and the ascending serotonin system in the Timothy syndrome type 2 (TS2-neo) mouse, which displays behavioral features consistent with the core triad of ASD. We find that TS2-neo mice exhibit enhanced serotonin tissue content and axon innervation of the dorsal striatum, as well as decreased serotonin turnover in the amygdala. These regionally specific alterations are accompanied by an enhanced active coping response during acute stress (forced swim), serotonin neuron Fos activity in the caudal dorsal raphe, and serotonin type 1A receptor-dependent feedback inhibition of the rostral dorsal raphe nuclei. Collectively, these results suggest that the global gain-of-function Cav1.2 mutation associated with Timothy syndrome has pleiotropic effects on the ascending serotonin system including neuroanatomical changes, regional differences in forebrain serotonin metabolism and feedback regulatory control mechanisms within the dorsal raphe. Altered activity of the ascending serotonin system continues to emerge as a common neural signature across several ASD mouse models, and the capacity for Cav1.2 L-type calcium channels to impact both serotonin structure and function has important implications for several neuropsychiatric conditions.
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Affiliation(s)
- Daniel G Ehlinger
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, USA.,Department of Anesthesia, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115, USA
| | - Kathryn G Commons
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, USA.,Department of Anesthesia, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115, USA
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17
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Commons KG, Cholanians AB, Babb JA, Ehlinger DG. The Rodent Forced Swim Test Measures Stress-Coping Strategy, Not Depression-like Behavior. ACS Chem Neurosci 2017; 8:955-960. [PMID: 28287253 PMCID: PMC5518600 DOI: 10.1021/acschemneuro.7b00042] [Citation(s) in RCA: 293] [Impact Index Per Article: 41.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The forced swim test (FST) measures coping strategy to an acute inescapable stress and thus provides unique insight into the neural limb of the stress response. Stress, particularly chronic stress, is a contributing factor to depression in humans and depression is associated with altered response to stress. In addition, drugs that are effective antidepressants in humans typically promote active coping strategy in the FST. As a consequence, passive coping in the FST has become loosely equated with depression and is often referred to as "depression-like" behavior. This terminology oversimplifies complex biology and misrepresents both the utility and limitations of the FST. The FST provides little construct- or face-validity to support an interpretation as "depression-like" behavior. While stress coping and the FST are arguably relevant to depression, there are likely many factors that can influence stress coping strategy. Importantly, there are other neuropsychiatric disorders characterized by altered responses to stress and difficulty in adapting to change. One of these is autism spectrum disorder (ASD), and several mouse genetic models of ASD exhibit altered stress-coping strategies in the FST. Here we review evidence that argues a more thoughtful consideration of the FST, and more precise terminology, would benefit the study of stress and disorders characterized by altered response to stress, which include but are not limited to depression.
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Affiliation(s)
- Kathryn G. Commons
- Department of Anesthesiology, Perioperative, and Pain Medicine, Boston Children’s Hospital and Department of Anesthesia, Harvard Medical School, 300 Longwood Avenue, Boston, Massachusetts 02115, United States
| | - Aram B. Cholanians
- Department of Anesthesiology, Perioperative, and Pain Medicine, Boston Children’s Hospital and Department of Anesthesia, Harvard Medical School, 300 Longwood Avenue, Boston, Massachusetts 02115, United States
| | - Jessica A. Babb
- Department of Anesthesiology, Perioperative, and Pain Medicine, Boston Children’s Hospital and Department of Anesthesia, Harvard Medical School, 300 Longwood Avenue, Boston, Massachusetts 02115, United States
| | - Daniel G. Ehlinger
- Department of Anesthesiology, Perioperative, and Pain Medicine, Boston Children’s Hospital and Department of Anesthesia, Harvard Medical School, 300 Longwood Avenue, Boston, Massachusetts 02115, United States
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18
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Neurotrophic Factors in Mouse Models of Autism Spectrum Disorder: Focus on BDNF and IGF-1. TRANSLATIONAL ANATOMY AND CELL BIOLOGY OF AUTISM SPECTRUM DISORDER 2017; 224:121-134. [DOI: 10.1007/978-3-319-52498-6_7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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Selective Disruption of Metabotropic Glutamate Receptor 5-Homer Interactions Mimics Phenotypes of Fragile X Syndrome in Mice. J Neurosci 2016; 36:2131-47. [PMID: 26888925 DOI: 10.1523/jneurosci.2921-15.2016] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
UNLABELLED Altered function of the Gq-coupled, Group 1 metabotropic glutamate receptors, specifically mGlu5, is implicated in multiple mouse models of autism and intellectual disability. mGlu5 dysfunction has been most well characterized in the fragile X syndrome mouse model, the Fmr1 knock-out (KO) mouse, where pharmacological and genetic reduction of mGlu5 reverses many phenotypes. mGlu5 is less associated with its scaffolding protein Homer in Fmr1 KO mice, and restoration of mGlu5-Homer interactions by genetic deletion of a short, dominant negative of Homer, H1a, rescues many phenotypes of Fmr1 KO mice. These results suggested that disruption of mGlu5-Homer leads to phenotypes of FXS. To test this idea, we examined mice with a knockin mutation of mGlu5 (F1128R; mGlu5(R/R)) that abrogates binding to Homer. Although FMRP levels were normal, mGlu5(R/R) mice mimicked multiple phenotypes of Fmr1 KO mice, including reduced mGlu5 association with the postsynaptic density, enhanced constitutive mGlu5 signaling to protein synthesis, deficits in agonist-induced translational control, protein synthesis-independent LTD, neocortical hyperexcitability, audiogenic seizures, and altered behaviors, including anxiety and sensorimotor gating. These results reveal new roles for the Homer scaffolds in regulation of mGlu5 function and implicate a specific molecular mechanism in a complex brain disease. SIGNIFICANCE STATEMENT Abnormal function of the metabotropic, or Gq-coupled, glutamate receptor 5 (mGlu5) has been implicated in neurodevelopmental disorders, including a genetic cause of intellectual disability and autism called fragile X syndrome. In brains of a mouse model of fragile X, mGlu5 is less associated with its binding partner Homer, a scaffolding protein that regulates mGlu5 localization to synapses and its ability to activate biochemical signaling pathways. Here we show that a mouse expressing a mutant mGlu5 that cannot bind to Homer is sufficient to mimic many of the biochemical, neurophysiological, and behavioral symptoms observed in the fragile X mouse. This work provides strong evidence that Homer-mGlu5 binding contributes to symptoms associated with neurodevelopmental disorders.
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Kazdoba TM, Leach PT, Yang M, Silverman JL, Solomon M, Crawley JN. Translational Mouse Models of Autism: Advancing Toward Pharmacological Therapeutics. Curr Top Behav Neurosci 2016; 28:1-52. [PMID: 27305922 PMCID: PMC5116923 DOI: 10.1007/7854_2015_5003] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Animal models provide preclinical tools to investigate the causal role of genetic mutations and environmental factors in the etiology of autism spectrum disorder (ASD). Knockout and humanized knock-in mice, and more recently knockout rats, have been generated for many of the de novo single gene mutations and copy number variants (CNVs) detected in ASD and comorbid neurodevelopmental disorders. Mouse models incorporating genetic and environmental manipulations have been employed for preclinical testing of hypothesis-driven pharmacological targets, to begin to develop treatments for the diagnostic and associated symptoms of autism. In this review, we summarize rodent behavioral assays relevant to the core features of autism, preclinical and clinical evaluations of pharmacological interventions, and strategies to improve the translational value of rodent models of autism.
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Affiliation(s)
- Tatiana M Kazdoba
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Room 1001A Research 2 Building 96, 4625 2nd Avenue, Sacramento, CA 95817, USA
| | - Prescott T Leach
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Room 1001A Research 2 Building 96, 4625 2nd Avenue, Sacramento, CA 95817, USA
| | - Mu Yang
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Room 1001A Research 2 Building 96, 4625 2nd Avenue, Sacramento, CA 95817, USA
| | - Jill L Silverman
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Room 1001A Research 2 Building 96, 4625 2nd Avenue, Sacramento, CA 95817, USA
| | - Marjorie Solomon
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Room 1001A Research 2 Building 96, 4625 2nd Avenue, Sacramento, CA 95817, USA
| | - Jacqueline N Crawley
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Room 1001A Research 2 Building 96, 4625 2nd Avenue, Sacramento, CA 95817, USA.
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Chandley MJ, Crawford JD, Szebeni A, Szebeni K, Ordway GA. NTRK2 expression levels are reduced in laser captured pyramidal neurons from the anterior cingulate cortex in males with autism spectrum disorder. Mol Autism 2015; 6:28. [PMID: 26000162 PMCID: PMC4440594 DOI: 10.1186/s13229-015-0023-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 04/24/2015] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The anterior cingulate cortex (ACC) is a brain area involved in modulating behavior associated with social interaction, disruption of which is a core feature of autism spectrum disorder (ASD). Functional brain imaging studies demonstrate abnormalities of the ACC in ASD as compared to typically developing control patients. However, little is known regarding the cellular basis of these functional deficits in ASD. Pyramidal neurons in the ACC are excitatory glutamatergic neurons and key cellular mediators of the neural output of the ACC. This study was designed to investigate the potential role of ACC pyramidal neurons in ASD brain pathology. METHODS Postmortem ACC tissue from carefully matched ASD and typically developing control donors was obtained from two national brain collections. Pyramidal neurons and surrounding astrocytes were separately collected from layer III of the ACC by laser capture microdissection. Isolated RNA was subjected to reverse transcription and endpoint PCR to determine gene expression levels for 16 synaptic genes relevant to glutamatergic neurotransmission. Cells were also collected from the prefrontal cortex (Brodmann area 10) to examine those genes demonstrating differences in expression in the ACC comparing typically developing and ASD donors. RESULTS The level of NTRK2 expression was robustly and significantly lower in pyramidal neurons from ASD donors as compared to typically developing donors. Levels of expression of GRIN1, GRM8, SLC1A1, and GRIP1 were modestly lower in pyramidal neurons from ASD donors, but statistical significance for these latter genes did not survive correction for multiple comparisons. No significant expression differences of any genes were found in astrocytes laser captured from the same neocortical area. In addition, expression levels of NTRK2 and other synaptic genes were normal in pyramidal neurons laser captured from the prefrontal cortex. CONCLUSIONS These studies demonstrate a unique pathology of neocortical pyramidal neurons of the ACC in ASD. NTRK2 encodes the tropomyosin receptor kinase B (TrkB), transmission through which neurotrophic factors modify differentiation, plasticity, and synaptic transmission. Reduced pyramidal neuron NTRK2 expression in the ACC could thereby contribute to abnormal neuronal activity and disrupt social behavior mediated by this brain region.
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Affiliation(s)
- Michelle J Chandley
- />Department of Health Sciences, College of Public Health, East Tennessee State University, P.O. Box 70673, Johnson City, TN 37614 USA
| | - Jessica D Crawford
- />Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, P.O. Box 70582, Johnson City, TN 37614 USA
| | - Attila Szebeni
- />Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, P.O. Box 70582, Johnson City, TN 37614 USA
| | - Katalin Szebeni
- />Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, P.O. Box 70582, Johnson City, TN 37614 USA
| | - Gregory A Ordway
- />Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, P.O. Box 70582, Johnson City, TN 37614 USA
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22
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Wang H, Doering LC. Autism spectrum disorders: emerging mechanisms and mechanism-based treatment. Front Cell Neurosci 2015; 9:183. [PMID: 26029053 PMCID: PMC4428121 DOI: 10.3389/fncel.2015.00183] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 04/27/2015] [Indexed: 12/27/2022] Open
Affiliation(s)
- Hansen Wang
- Faculty of Medicine, University of Toronto Toronto, ON, Canada
| | - Laurie C Doering
- Department of Pathology and Molecular Medicine, Faculty of Health Sciences, McMaster University Hamilton, ON, Canada
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Wang H, Pati S, Pozzo-Miller L, Doering LC. Targeted pharmacological treatment of autism spectrum disorders: fragile X and Rett syndromes. Front Cell Neurosci 2015; 9:55. [PMID: 25767435 PMCID: PMC4341567 DOI: 10.3389/fncel.2015.00055] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Accepted: 02/05/2015] [Indexed: 12/27/2022] Open
Abstract
Autism spectrum disorders (ASDs) are genetically and clinically heterogeneous and lack effective medications to treat their core symptoms. Studies of syndromic ASDs caused by single gene mutations have provided insights into the pathophysiology of autism. Fragile X and Rett syndromes belong to the syndromic ASDs in which preclinical studies have identified rational targets for drug therapies focused on correcting underlying neural dysfunction. These preclinical discoveries are increasingly translating into exciting human clinical trials. Since there are significant molecular and neurobiological overlaps among ASDs, targeted treatments developed for fragile X and Rett syndromes may be helpful for autism of different etiologies. Here, we review the targeted pharmacological treatment of fragile X and Rett syndromes and discuss related issues in both preclinical studies and clinical trials of potential therapies for the diseases.
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Affiliation(s)
- Hansen Wang
- Faculty of Medicine, University of Toronto, 1 King's College Circle Toronto, ON, Canada
| | - Sandipan Pati
- Department of Neurology, Epilepsy Division, The University of Alabama at Birmingham Birmingham, AL, USA
| | - Lucas Pozzo-Miller
- Department of Neurobiology, Civitan International Research Center, The University of Alabama at Birmingham Birmingham, AL, USA
| | - Laurie C Doering
- Faculty of Health Sciences, Department of Pathology and Molecular Medicine, McMaster University Hamilton, ON, Canada
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24
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Hanson AC, Hagerman RJ. Serotonin dysregulation in Fragile X Syndrome: implications for treatment. Intractable Rare Dis Res 2014; 3:110-7. [PMID: 25606361 PMCID: PMC4298641 DOI: 10.5582/irdr.2014.01027] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 11/28/2014] [Indexed: 12/29/2022] Open
Abstract
Fragile X Syndrome (FXS) is a trinucleotide repeat disorder that results in the silencing of the Fragile X Mental Retardation 1 gene (FMR1), leading to a lack of the FMR1 protein (FMRP). FMRP is an mRNA-binding protein that regulates the translation of hundreds of mRNAs important for synaptic plasticity. Several of these pathways have been identified and have guided the development of targeted treatments for FXS. Here we present evidence that serotonin is dysregulated in FXS and treatment with the selective serotonin reuptake inhibitor (SSRI) sertraline may be beneficial for individuals with FXS, particularly in early childhood.
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Affiliation(s)
| | - Randi J Hagerman
- UC Davis MIND Institute and Department of Pediatrics, UC Davis Medical Center, Sacramento, CA, USA
- Address correspondence to: Dr. Randi J. Hagerman, UC Davis MIND Institute and Department of Pediatrics, UC Davis Medical Center, Sacramento, CA 95817, USA. E-mail:
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25
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Lozano R, Rosero CA, Hagerman RJ. Fragile X spectrum disorders. Intractable Rare Dis Res 2014; 3:134-46. [PMID: 25606363 PMCID: PMC4298643 DOI: 10.5582/irdr.2014.01022] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 11/28/2014] [Indexed: 12/13/2022] Open
Abstract
The fragile X mental retardation 1 gene (FMR1), which codes for the fragile X mental retardation 1 protein (FMRP), is located at Xp27.3. The normal allele of the FMR1 gene typically has 5 to 40 CGG repeats in the 5' untranslated region; abnormal alleles of dynamic mutations include the full mutation (> 200 CGG repeats), premutation (55-200 CGG repeats) and the gray zone mutation (45-54 CGG repeats). Premutation carriers are common in the general population with approximately 1 in 130-250 females and 1 in 250-810 males, whereas the full mutation and Fragile X syndrome (FXS) occur in approximately 1 in 4000 to 1 in 7000. FMR1 mutations account for a variety of phenotypes including the most common monogenetic cause of inherited intellectual disability (ID) and autism (FXS), the most common genetic form of ovarian failure, the fragile X-associated primary ovarian insufficiency (FXPOI, premutation); and fragile X-associated tremor/ataxia syndrome (FXTAS, premutation). The premutation can also cause developmental problems including ASD and ADHD especially in boys and psychopathology including anxiety and depression in children and adults. Some premutation carriers can have a deficit of FMRP and some unmethylated full mutation individuals can have elevated FMR1 mRNA that is considered a premutation problem. Therefore the term "Fragile X Spectrum Disorder" (FXSD) should be used to include the wide range of overlapping phenotypes observed in affected individuals with FMR1 mutations. In this review we focus on the phenotypes and genotypes of children with FXSD.
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Affiliation(s)
- Reymundo Lozano
- UC Davis MIND Institute and Department of Pediatrics, UC Davis Medical Center, Sacramento, CA, USA
- Address correspondence to: Dr. Reymundo Lozano, UC Davis MIND Institute and Department of Pediatrics, UC Davis Medical Center, Sacramento, CA, USA. E-mail:
| | - Carolina Alba Rosero
- Instituto Colombiano del Sistema Nervioso, Clínica Montserrat, Bogotá D.C, Colombia
| | - Randi J Hagerman
- UC Davis MIND Institute and Department of Pediatrics, UC Davis Medical Center, Sacramento, CA, USA
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26
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Kazdoba TM, Leach PT, Silverman JL, Crawley JN. Modeling fragile X syndrome in the Fmr1 knockout mouse. Intractable Rare Dis Res 2014; 3:118-33. [PMID: 25606362 PMCID: PMC4298642 DOI: 10.5582/irdr.2014.01024] [Citation(s) in RCA: 161] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 11/28/2014] [Indexed: 11/05/2022] Open
Abstract
Fragile X Syndrome (FXS) is a commonly inherited form of intellectual disability and one of the leading genetic causes for autism spectrum disorder. Clinical symptoms of FXS can include impaired cognition, anxiety, hyperactivity, social phobia, and repetitive behaviors. FXS is caused by a CGG repeat mutation which expands a region on the X chromosome containing the FMR1 gene. In FXS, a full mutation (> 200 repeats) leads to hypermethylation of FMR1, an epigenetic mechanism that effectively silences FMR1 gene expression and reduces levels of the FMR1 gene product, fragile X mental retardation protein (FMRP). FMRP is an RNA-binding protein that is important for the regulation of protein expression. In an effort to further understand how loss of FMR1 and FMRP contribute to FXS symptomology, several FXS animal models have been created. The most well characterized rodent model is the Fmr1 knockout (KO) mouse, which lacks FMRP protein due to a disruption in its Fmr1 gene. Here, we review the behavioral phenotyping of the Fmr1 KO mouse to date, and discuss the clinical relevance of this mouse model to the human FXS condition. While much remains to be learned about FXS, the Fmr1 KO mouse is a valuable tool for understanding the repercussions of functional loss of FMRP and assessing the efficacy of pharmacological compounds in ameliorating the molecular and behavioral phenotypes relevant to FXS.
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Affiliation(s)
- Tatiana M. Kazdoba
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California, Davis, School of Medicine, Sacramento, CA, USA
- Address correspondence to: Dr. Tatiana M. Kazdoba, MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California, Davis, School of Medicine, Sacramento, Research II Building 96, 4625 2nd Avenue, Sacramento, CA 95817, USA. E-mail:
| | - Prescott T. Leach
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California, Davis, School of Medicine, Sacramento, CA, USA
| | - Jill L. Silverman
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California, Davis, School of Medicine, Sacramento, CA, USA
| | - Jacqueline N. Crawley
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California, Davis, School of Medicine, Sacramento, CA, USA
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Nimodipine activates TrkB neurotrophin receptors and induces neuroplastic and neuroprotective signaling events in the mouse hippocampus and prefrontal cortex. Cell Mol Neurobiol 2014; 35:189-96. [PMID: 25204460 DOI: 10.1007/s10571-014-0110-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 09/01/2014] [Indexed: 12/14/2022]
Abstract
The L-type calcium channel blocker nimodipine improves clinical outcome produced by delayed cortical ischemia or vasospasm associated with subarachnoid hemorrhage. While vasoactive mechanisms are strongly implicated in these therapeutic actions of nimodipine, we sought to test whether nimodipine might also regulate neurotrophic and neuroplastic signaling events associated with TrkB neurotrophin receptor activation. Adult male mice were acutely treated with vehicle or nimodipine (10 mg/kg, s.c., 1.5 h) after which the phosphorylation states of TrkB, cyclic-AMP response element binding protein (CREB), protein kinase B (Akt), extracellular regulated kinase (ERK), mammalian target of rapamycin (mTor) and p70S6 kinase (p70S6k) from prefrontal cortex and hippocampus were assessed. Nimodipine increased the phosphorylation of the TrkB catalytic domain and the phosphoslipase-Cγ1 (PLCγ1) domain, whereas phosphorylation of the TrkB Shc binding site remained unaltered. Nimodipine-induced TrkB phosphorylation was associated with increased phosphorylation levels of Akt and CREB in the prefrontal cortex and the hippocampus whereas phosphorylation of ERK, mTor and p70S6k remained unaltered. Nimodipine-induced TrkB signaling was not associated with changes in BDNF mRNA or protein levels. These nimodipine-induced changes on TrkB signaling mimic those produced by antidepressant drugs and thus propose common mechanisms and long-term functional consequences for the effects of these medications. This work provides a strong basis for investigating the role of TrkB-associated signaling underlying the neuroprotective and neuroplastic effects of nimodipine in translationally relevant animal models of brain trauma or compromised synaptic plasticity.
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