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Jonak CR, Assad SA, Garcia TA, Sandhu MS, Rumschlag JA, Razak KA, Binder DK. Phenotypic analysis of multielectrode array EEG biomarkers in developing and adult male Fmr1 KO mice. Neurobiol Dis 2024; 195:106496. [PMID: 38582333 DOI: 10.1016/j.nbd.2024.106496] [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: 02/03/2024] [Revised: 04/03/2024] [Accepted: 04/03/2024] [Indexed: 04/08/2024] Open
Abstract
Fragile X Syndrome (FXS) is a leading known genetic cause of intellectual disability with symptoms that include increased anxiety and social and sensory processing deficits. Recent electroencephalographic (EEG) studies in humans with FXS have identified neural oscillation deficits that include increased resting state gamma power, increased amplitude of auditory evoked potentials, and reduced phase locking of sound-evoked gamma oscillations. Similar EEG phenotypes are present in mouse models of FXS, but very little is known about the development of such abnormal responses. In the current study, we employed a 30-channel mouse multielectrode array (MEA) system to record and analyze resting and stimulus-evoked EEG signals in male P21 and P91 WT and Fmr1 KO mice. This led to several novel findings. First, P91, but not P21, Fmr1 KO mice have significantly increased resting EEG power in the low- and high-gamma frequency bands. Second, both P21 and P91 Fmr1 KO mice have markedly attenuated inter-trial phase coherence (ITPC) to spectrotemporally dynamic auditory stimuli as well as to 40 Hz and 80 Hz auditory steady-state response (ASSR) stimuli. This suggests abnormal temporal processing from early development that may lead to abnormal speech and language function in FXS. Third, we found hemispheric asymmetry of fast temporal processing in the mouse auditory cortex in WT but not Fmr1 KO mice. Together, these findings define a set of EEG phenotypes in young and adult mice that can serve as translational targets for genetic and pharmacological manipulation in phenotypic rescue studies.
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Affiliation(s)
- Carrie R Jonak
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, United States of America
| | - Samantha A Assad
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, United States of America
| | - Terese A Garcia
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, United States of America
| | - Manbir S Sandhu
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, United States of America
| | - Jeffrey A Rumschlag
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, Charleston, SC, United States of America
| | - Khaleel A Razak
- Neuroscience Graduate Program, University of California, Riverside, CA, United States of America; Department of Psychology, University of California, Riverside, CA, United States of America
| | - Devin K Binder
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, United States of America; Neuroscience Graduate Program, University of California, Riverside, CA, United States of America.
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Bhandari K, Kanodia H, Donato F, Caroni P. Selective vulnerability of the ventral hippocampus-prelimbic cortex axis parvalbumin interneuron network underlies learning deficits of fragile X mice. Cell Rep 2024; 43:114124. [PMID: 38630591 DOI: 10.1016/j.celrep.2024.114124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 03/07/2024] [Accepted: 04/02/2024] [Indexed: 04/19/2024] Open
Abstract
High-penetrance mutations affecting mental health can involve genes ubiquitously expressed in the brain. Whether the specific patterns of dysfunctions result from ubiquitous circuit deficits or might reflect selective vulnerabilities of targetable subnetworks has remained unclear. Here, we determine how loss of ubiquitously expressed fragile X mental retardation protein (FMRP), the cause of fragile X syndrome, affects brain networks in Fmr1y/- mice. We find that in wild-type mice, area-specific knockout of FMRP in the adult mimics behavioral consequences of area-specific silencing. By contrast, the functional axis linking the ventral hippocampus (vH) to the prelimbic cortex (PreL) is selectively affected in constitutive Fmr1y/- mice. A chronic alteration in late-born parvalbumin interneuron networks across the vH-PreL axis rescued by VIP signaling specifically accounts for deficits in vH-PreL theta-band network coherence, ensemble assembly, and learning functions of Fmr1y/- mice. Therefore, vH-PreL axis function exhibits a selective vulnerability to loss of FMRP in the vH or PreL, leading to learning and memory dysfunctions in fragile X mice.
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Affiliation(s)
- Komal Bhandari
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Harsh Kanodia
- Biozentrum, University of Basel, 4058 Basel, Switzerland
| | - Flavio Donato
- Biozentrum, University of Basel, 4058 Basel, Switzerland
| | - Pico Caroni
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland.
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3
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Wadle SL, Ritter TC, Wadle TTX, Hirtz JJ. Topography and Ensemble Activity in the Auditory Cortex of a Mouse Model of Fragile X Syndrome. eNeuro 2024; 11:ENEURO.0396-23.2024. [PMID: 38627066 PMCID: PMC11097631 DOI: 10.1523/eneuro.0396-23.2024] [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: 09/14/2023] [Revised: 03/11/2024] [Accepted: 04/01/2024] [Indexed: 05/18/2024] Open
Abstract
Autism spectrum disorder (ASD) is often associated with social communication impairments and specific sound processing deficits, for example, problems in following speech in noisy environments. To investigate underlying neuronal processing defects located in the auditory cortex (AC), we performed two-photon Ca2+ imaging in FMR1 (fragile X messenger ribonucleoprotein 1) knock-out (KO) mice, a model for fragile X syndrome (FXS), the most common cause of hereditary ASD in humans. For primary AC (A1) and the anterior auditory field (AAF), topographic frequency representation was less ordered compared with control animals. We additionally analyzed ensemble AC activity in response to various sounds and found subfield-specific differences. In A1, ensemble correlations were lower in general, while in secondary AC (A2), correlations were higher in response to complex sounds, but not to pure tones. Furthermore, sound specificity of ensemble activity was decreased in AAF. Repeating these experiments 1 week later revealed no major differences regarding representational drift. Nevertheless, we found subfield- and genotype-specific changes in ensemble correlation values between the two times points, hinting at alterations in network stability in FMR1 KO mice. These detailed insights into AC network activity and topography in FMR1 KO mice add to the understanding of auditory processing defects in FXS.
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Affiliation(s)
- Simon L Wadle
- Physiology of Neuronal Networks, Department of Biology, RPTU University of Kaiserslautern-Landau, Kaiserslautern D-67663, Germany
| | - Tamara C Ritter
- Physiology of Neuronal Networks, Department of Biology, RPTU University of Kaiserslautern-Landau, Kaiserslautern D-67663, Germany
| | - Tatjana T X Wadle
- Physiology of Neuronal Networks, Department of Biology, RPTU University of Kaiserslautern-Landau, Kaiserslautern D-67663, Germany
| | - Jan J Hirtz
- Physiology of Neuronal Networks, Department of Biology, RPTU University of Kaiserslautern-Landau, Kaiserslautern D-67663, Germany
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Dusing MR, LaSarge CL, Drake AW, Westerkamp GC, McCoy C, Hetzer SM, Kraus KL, Pedapati EV, Danzer SC. Transient Seizure Clusters and Epileptiform Activity Following Widespread Bilateral Hippocampal Interneuron Ablation. eNeuro 2024; 11:ENEURO.0317-23.2024. [PMID: 38575351 PMCID: PMC11036118 DOI: 10.1523/eneuro.0317-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 03/28/2024] [Accepted: 03/29/2024] [Indexed: 04/06/2024] Open
Abstract
Interneuron loss is a prominent feature of temporal lobe epilepsy in both animals and humans and is hypothesized to be critical for epileptogenesis. As loss occurs concurrently with numerous other potentially proepileptogenic changes, however, the impact of interneuron loss in isolation remains unclear. For the present study, we developed an intersectional genetic approach to induce bilateral diphtheria toxin-mediated deletion of Vgat-expressing interneurons from dorsal and ventral hippocampus. In a separate group of mice, the same population was targeted for transient neuronal silencing with DREADDs. Interneuron ablation produced dramatic seizure clusters and persistent epileptiform activity. Surprisingly, after 1 week seizure activity declined precipitously and persistent epileptiform activity disappeared. Occasional seizures (≈1/day) persisted to the end of the experiment at 4 weeks. In contrast to the dramatic impact of interneuron ablation, transient silencing produced large numbers of interictal spikes, a significant but modest increase in seizure occurrence and changes in EEG frequency band power. Taken together, findings suggest that the hippocampus regains relative homeostasis-with occasional breakthrough seizures-in the face of an extensive and abrupt loss of interneurons.
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Affiliation(s)
- Mary R Dusing
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
| | - Candi L LaSarge
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio 45229-3039
| | - Austin W Drake
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio 45229-3039
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039
| | - Grace C Westerkamp
- Division of Child Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
| | - Carlie McCoy
- Division of Neurosurgery, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
| | - Shelby M Hetzer
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio 45229-3039
| | - Kimberly L Kraus
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio 45229-3039
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039
| | - Ernest V Pedapati
- Division of Child Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
| | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio 45229-3039
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039
- Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039
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5
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Saraf TS, Chen Y, Tyagi R, Canal CE. Altered brain serotonin 5-HT 1A receptor expression and function in juvenile Fmr1 knockout mice. Neuropharmacology 2024; 245:109774. [PMID: 37923121 DOI: 10.1016/j.neuropharm.2023.109774] [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: 07/09/2023] [Revised: 10/01/2023] [Accepted: 10/21/2023] [Indexed: 11/07/2023]
Abstract
There are no approved pharmacotherapies for fragile X syndrome (FXS), a rare neurodevelopmental disorder caused by a mutation in the FMR1 promoter region that leads to various symptoms, including intellectual disability and auditory hypersensitivity. The gene that encodes inhibitory serotonin 1A receptors (5-HT1ARs) is differentially expressed in embryonic brain tissue from individuals with FXS, and 5-HT1ARs are highly expressed in neural systems that are disordered in FXS, providing a rationale to focus on 5-HT1ARs as targets to treat symptoms of FXS. We examined agonist-labeled 5-HT1AR densities in male and female Fmr1 knockout mice and found no differences in whole-brain 5-HT1AR expression in adult control compared to Fmr1 knockout mice. However, juvenile Fmr1 knockout mice had lower whole-brain 5-HT1AR expression than age-matched controls. Consistent with these results, juvenile Fmr1 knockout mice showed reduced behavioral responses elicited by the 5-HT1AR agonist (R)-8-OH-DPAT, effects blocked by the selective 5-HT1AR antagonist, WAY-100635. Also, treatment with the selective 5-HT1AR agonist, NLX-112, dose-dependently prevented audiogenic seizures (AGS) in juvenile Fmr1 knockout mice, an effect reversed by WAY-100635. Suggestive of a potential role for 5-HT1ARs in regulating AGS, compared to males, female Fmr1 knockout mice had a lower prevalence of AGS and higher expression of antagonist-labeled 5-HT1ARs in the inferior colliculus and auditory cortex. These results provide preclinical support that 5-HT1AR agonists may be therapeutic for young individuals with FXS hypersensitive to auditory stimuli.
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Affiliation(s)
- Tanishka S Saraf
- Mercer University, College of Pharmacy, Department of Pharmaceutical Sciences, 3001 Mercer University Drive, Atlanta, GA, 30341, USA
| | - Yiming Chen
- Mercer University, College of Pharmacy, Department of Pharmaceutical Sciences, 3001 Mercer University Drive, Atlanta, GA, 30341, USA
| | - Richa Tyagi
- Mercer University, College of Pharmacy, Department of Pharmaceutical Sciences, 3001 Mercer University Drive, Atlanta, GA, 30341, USA
| | - Clinton E Canal
- Mercer University, College of Pharmacy, Department of Pharmaceutical Sciences, 3001 Mercer University Drive, Atlanta, GA, 30341, USA.
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Ethridge LE, Pedapati EV, Schmitt LM, Norris JE, Auger E, De Stefano LA, Sweeney JA, Erickson CA. Validating brain activity measures as reliable indicators of individual diagnostic group and genetically mediated sub-group membership Fragile X Syndrome. RESEARCH SQUARE 2024:rs.3.rs-3849272. [PMID: 38313274 PMCID: PMC10836101 DOI: 10.21203/rs.3.rs-3849272/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2024]
Abstract
Recent failures translating preclinical behavioral treatment effects to positive clinical trial results in humans with Fragile X Syndrome (FXS) support refocusing attention on biological pathways and associated measures, such as electroencephalography (EEG), with strong translational potential and small molecule target engagement. This study utilized guided machine learning to test promising translational EEG measures (resting power and auditory chirp oscillatory variables) in a large heterogeneous sample of individuals with FXS to identify best performing EEG variables for reliably separating individuals with FXS, and genetically-mediated subgroups within FXS, from typically developing controls. Best performing variables included resting relative frontal theta power, all combined whole-head resting power bands, posterior peak alpha frequency (PAF), combined PAF across all measured regions, combined theta, alpha, and gamma power during the chirp, and all combined chirp oscillatory variables. Sub-group analyses best discriminated non-mosaic FXS males via whole-head resting relative power (AUC = .9250), even with data reduced to a 20-channel clinical montage. FXS females were nearly perfectly discriminated by combined theta, alpha, and gamma power during the chirp (AUC = .9522). Results support use of resting and auditory oscillatory tasks to reliably identify neural deficit in FXS, and to identify specific translational targets for genetically-mediated sub-groups, supporting potential points for stratification.
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7
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Van't Spijker HM, Richter JD. FMRP regulation of aggrecan mRNA translation controls perineuronal net development. J Neurochem 2024. [PMID: 38225196 DOI: 10.1111/jnc.16048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 12/19/2023] [Accepted: 01/01/2024] [Indexed: 01/17/2024]
Abstract
Perineuronal nets (PNNs) are mesh-like structures on the surfaces of parvalbumin-expressing inhibitory and other neurons, and consist of proteoglycans such as aggrecan, brevican, and neurocan. PNNs regulate the Excitatory/Inhibitory (E/I) balance in the brain and are formed at the closure of critical periods of plasticity during development. PNN formation is disrupted in Fragile X Syndrome, which is caused by silencing of the fragile X messenger ribonucleoprotein 1 (Fmr1) gene and loss of its protein product FMRP. FXS is characterized by impaired synaptic plasticity resulting in neuronal hyperexcitability and E/I imbalance. Here, we investigate how PNN formation is altered in FXS. PNNs are reduced in Fmr1 KO mouse brain when examined by staining for the lectin Wisteria floribunda agglutin (WFA) and aggrecan. Examination of PNNs by WFA staining at P14 and P42 in the hippocampus, somatosensory cortex, and retrosplenial cortex shows that they were reduced in these brain regions at P14 but mostly less so at P42 in Fmr1 KO mice. However, some differential FMRP regulation of PNN development in these brain regions persists, perhaps caused by asynchrony in PNN development between brain regions in wild-type animals. During development, aggrecan PNN levels in the brain were reduced in all brain regions in Fmr1 KO mice. Aggrecan mRNA levels were unchanged at these times, suggesting that FMRP is normally an activator of aggrecan mRNA translation. This hypothesis is buttressed by the observations that FMRP binds aggrecan mRNA and that ribosome profiling data show that aggrecan mRNA is associated with reduced numbers of ribosomes in Fmr1 KO mouse brain, indicating reduced translational efficiency. Moreover, aggrecan mRNA poly(A) tail length is also reduced in Fmr1 KO mouse brain, suggesting a relationship between polyadenylation and translational control. We propose a model where FMRP modulates PNN formation through translational up-regulation of aggrecan mRNA polyadenylation and translation.
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Affiliation(s)
- Heleen M Van't Spijker
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Joel D Richter
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
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Sanchez B, Kraszewski P, Lee S, Cope EC. From molecules to behavior: Implications for perineuronal net remodeling in learning and memory. J Neurochem 2023. [PMID: 38158878 DOI: 10.1111/jnc.16036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 11/30/2023] [Accepted: 12/11/2023] [Indexed: 01/03/2024]
Abstract
Perineuronal nets (PNNs) are condensed extracellular matrix (ECM) structures found throughout the central nervous system that regulate plasticity. They consist of a heterogeneous mix of ECM components that form lattice-like structures enwrapping the cell body and proximal dendrites of particular neurons. During development, accumulating research has shown that the closure of various critical periods of plasticity is strongly linked to experience-driven PNN formation and maturation. PNNs provide an interface for synaptic contacts within the holes of the structure, generally promoting synaptic stabilization and restricting the formation of new synaptic connections in the adult brain. In this way, they impact both synaptic structure and function, ultimately influencing higher cognitive processes. PNNs are highly plastic structures, changing their composition and distribution throughout life and in response to various experiences and memory disorders, thus serving as a substrate for experience- and disease-dependent cognitive function. In this review, we delve into the proposed mechanisms by which PNNs shape plasticity and memory function, highlighting the potential impact of their structural components, overall architecture, and dynamic remodeling on functional outcomes in health and disease.
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Affiliation(s)
- Brenda Sanchez
- Department of Neuroscience, University of Virginia School of Medicine, Virginia, USA
| | - Piotr Kraszewski
- Department of Neuroscience, University of Virginia School of Medicine, Virginia, USA
| | - Sabrina Lee
- Department of Neuroscience, University of Virginia School of Medicine, Virginia, USA
| | - Elise C Cope
- Department of Neuroscience, University of Virginia School of Medicine, Virginia, USA
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Liu R, Pedapati EV, Schmitt LM, Shaffer RC, Smith EG, Dominick KC, DeStefano LA, Westerkamp G, Horn P, Sweeney JA, Erickson CA. Reliability of resting-state electrophysiology in fragile X syndrome. Biomark Neuropsychiatry 2023; 9:100070. [PMID: 38817342 PMCID: PMC11138258 DOI: 10.1016/j.bionps.2023.100070] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/01/2024] Open
Abstract
Objective Fragile X Syndrome (FXS) is the leading monogenic cause of intellectual disability and autism spectrum disorder. Currently, there are no established biomarkers for predicting and monitoring drug effects in FXS, and no approved therapies are available. Previous studies have shown electrophysiological changes in the brain using electroencephalography (EEG) in individuals with FXS and animal models. These changes may be influenced by drug therapies. In this study, we aimed to assess the reliability of resting-state EEG measures in individuals with FXS, which could potentially serve as a biomarker for drug discovery. Methods We collected resting-state EEG data from 35 individuals with FXS participating in placebo-controlled clinical trials (23 males, 12 females; visit age mean+/-std 25.6 +/-8.3). The data were analyzed for various spectral features using intraclass correlation analysis to evaluate test-retest reliability. The intervals between EEG recordings ranged from same-day measurements to up to six weeks apart. Results Our results showed high reliability for most spectral features, with same-day reliability exceeding 0.8. Features of interest demonstrated ICC values of 0.60 or above at longer intervals. Among the features, alpha band relative power exhibited the highest reliability. Conclusion These findings indicate that resting-state EEG can provide consistent and reproducible measures of brain activity in individuals with FXS. This supports the potential use of EEG as an objective biomarker for evaluating the effects of new drugs in FXS. Significance The reliable measurements obtained from power spectrum-based resting-state EEG make it a promising tool for assessing the impact of small molecule drugs in FXS.
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Affiliation(s)
- Rui Liu
- Cincinnati Children’s Hospital Medical Center, United States
| | - Ernest V. Pedapati
- Cincinnati Children’s Hospital Medical Center, United States
- University of Cincinnati, United States
| | - Lauren M. Schmitt
- Cincinnati Children’s Hospital Medical Center, United States
- University of Cincinnati, United States
| | - Rebecca C. Shaffer
- Cincinnati Children’s Hospital Medical Center, United States
- University of Cincinnati, United States
| | - Elizabeth G. Smith
- Cincinnati Children’s Hospital Medical Center, United States
- University of Cincinnati, United States
| | - Kelli C. Dominick
- Cincinnati Children’s Hospital Medical Center, United States
- University of Cincinnati, United States
| | | | | | - Paul Horn
- Cincinnati Children’s Hospital Medical Center, United States
- University of Cincinnati, United States
| | | | - Craig A. Erickson
- Cincinnati Children’s Hospital Medical Center, United States
- University of Cincinnati, United States
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Kaczmarek KT, Protokowicz K, Kaczmarek L. Matrix metalloproteinase-9: A magic drug target in neuropsychiatry? J Neurochem 2023. [PMID: 37791997 DOI: 10.1111/jnc.15976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 09/12/2023] [Accepted: 09/15/2023] [Indexed: 10/05/2023]
Abstract
Neuropsychiatric conditions represent a major medical and societal challenge. The etiology of these conditions is very complex and combines genetic and environmental factors. The latter, for example, excessive maternal or early postnatal inflammation, as well as various forms of psychotrauma, often act as triggers leading to mental illness after a prolonged latent period (sometimes years). Matrix metalloproteinase-9 (MMP-9) is an extracellularly and extrasynaptic operating protease that is markedly activated in response to the aforementioned environmental insults. MMP-9 has also been shown to play a pivotal role in the plasticity of excitatory synapses, which, in its aberrant form, has repeatedly been implicated in the etiology of mental illness. In this conceptual review, we evaluate the experimental and clinical evidence supporting the claim that MMP-9 is uniquely positioned to be considered a drug target for ameliorating the adverse effects of environmental insults on the development of a variety of neuropsychiatric conditions, such as schizophrenia, bipolar disorder, major depression, autism spectrum disorders, addiction, and epilepsy. We also identify specific challenges and bottlenecks hampering the translation of knowledge on MMP-9 into new clinical treatments for the conditions above and suggest ways to overcome these barriers.
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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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12
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Monday HR, Wang HC, Feldman DE. Circuit-level theories for sensory dysfunction in autism: convergence across mouse models. Front Neurol 2023; 14:1254297. [PMID: 37745660 PMCID: PMC10513044 DOI: 10.3389/fneur.2023.1254297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 08/14/2023] [Indexed: 09/26/2023] Open
Abstract
Individuals with autism spectrum disorder (ASD) exhibit a diverse range of behavioral features and genetic backgrounds, but whether different genetic forms of autism involve convergent pathophysiology of brain function is unknown. Here, we analyze evidence for convergent deficits in neural circuit function across multiple transgenic mouse models of ASD. We focus on sensory areas of neocortex, where circuit differences may underlie atypical sensory processing, a central feature of autism. Many distinct circuit-level theories for ASD have been proposed, including increased excitation-inhibition (E-I) ratio and hyperexcitability, hypofunction of parvalbumin (PV) interneuron circuits, impaired homeostatic plasticity, degraded sensory coding, and others. We review these theories and assess the degree of convergence across ASD mouse models for each. Behaviorally, our analysis reveals that innate sensory detection behavior is heightened and sensory discrimination behavior is impaired across many ASD models. Neurophysiologically, PV hypofunction and increased E-I ratio are prevalent but only rarely generate hyperexcitability and excess spiking. Instead, sensory tuning and other aspects of neural coding are commonly degraded and may explain impaired discrimination behavior. Two distinct phenotypic clusters with opposing neural circuit signatures are evident across mouse models. Such clustering could suggest physiological subtypes of autism, which may facilitate the development of tailored therapeutic approaches.
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Affiliation(s)
- Hannah R. Monday
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
| | | | - Daniel E. Feldman
- Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
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Leung BK, Merlin S, Walker AK, Lawther AJ, Paxinos G, Eapen V, Clarke R, Balleine BW, Furlong TM. Immp2l knockdown in male mice increases stimulus-driven instrumental behaviour but does not alter goal-directed learning or neuron density in cortico-striatal circuits in a model of Tourette syndrome and autism spectrum disorder. Behav Brain Res 2023; 452:114610. [PMID: 37541448 DOI: 10.1016/j.bbr.2023.114610] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 07/22/2023] [Accepted: 08/01/2023] [Indexed: 08/06/2023]
Abstract
Cortico-striatal neurocircuits mediate goal-directed and habitual actions which are necessary for adaptive behaviour. It has recently been proposed that some of the core symptoms of autism spectrum disorder (ASD) and Gilles de la Tourette syndrome (GTS), such as tics and other repetitive behaviours, may emerge because of imbalances in these neurocircuits. We have recently developed a model of ASD and GTS by knocking down Immp2l, a mitochondrial gene frequently associated with these disorders. The current study sought to determine whether Immp2l knockdown (KD) in male mice alters flexible, goal- or cue- driven behaviour using procedures specifically designed to examine response-outcome and stimulus-response associations, which underlie goal-directed and habitual behaviour, respectively. Whether Immp2l KD alters neuron density in cortico-striatal neurocircuits known to regulate these behaviours was also examined. Immp2l KD mice and wild type-like mice (WT) were trained on Pavlovian and instrumental learning procedures where auditory cues predicted food delivery and lever-press responses earned a food outcome. It was demonstrated that goal-directed learning was not changed for Immp2l KD mice compared to WT mice, as lever-press responses were sensitive to changes in the value of the food outcome, and to contingency reversal and degradation. There was also no difference in the capacity of KD mice to form habitual behaviours compared to WT mice following extending training of the instrumental action. However, Immp2l KD mice were more responsive to auditory stimuli paired with food as indicated by a non-specific increase in lever response rates during Pavlovian-to-instrumental transfer. Finally, there were no alterations to neuron density in striatum or any prefrontal cortex or limbic brain structures examined. Thus, the current study suggests that Immp2l is not necessary for learned maladaptive goal or stimulus driven behaviours in ASD or GTS, but that it may contribute to increased capacity for external stimuli to drive behaviour. Alterations to stimulus-driven behaviour could potentially influence the expression of tics and repetitive behaviours, suggesting that genetic alterations to Immp2l may contribute to these core symptoms in ASD and GTS. Given that this is the first application of this battery of instrumental learning procedures to a mouse model of ASD or GTS, it is an important initial step in determining the contribution of known risk-genes to goal-directed versus habitual behaviours, which should be more broadly applied to other rodent models of ASD and GTS in the future.
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Affiliation(s)
- Beatrice K Leung
- Decision Neuroscience Laboratory, School of Psychology, University of New South Wales, Sydney, NSW, Australia
| | - Sam Merlin
- School of Science, Western Sydney University, Campbelltown, Sydney, NSW, Australia
| | - Adam K Walker
- Laboratory of ImmunoPsychiatry, Neuroscience Research Australia, Randwick, NSW, Australia; Discipline of Psychiatry and Mental Health, University of New South Wales, NSW, Australia
| | - Adam J Lawther
- Laboratory of ImmunoPsychiatry, Neuroscience Research Australia, Randwick, NSW, Australia
| | - George Paxinos
- Neuroscience Research Australia, Randwick, NSW, Australia; School of Biomedical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Valsamma Eapen
- Discipline of Psychiatry and Mental Health, University of New South Wales, NSW, Australia; Mental Health Research Unit, South Western Sydney Local Health District, Liverpool, Australia
| | - Raymond Clarke
- Ingham Institute, Discipline of Psychiatry, University of New South Wales, Sydney, NSW, Australia
| | - Bernard W Balleine
- Decision Neuroscience Laboratory, School of Psychology, University of New South Wales, Sydney, NSW, Australia
| | - Teri M Furlong
- Neuroscience Research Australia, Randwick, NSW, Australia; School of Biomedical Sciences, University of New South Wales, Sydney, NSW, Australia.
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14
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Pedapati EV, Sweeney JA, Schmitt LM, Ethridge LE, Miyakoshi M, Liu R, Smith E, Shaffer RC, Wu SW, Gilbert DL, Horn PS, Erickson C. Empirical Frequency Bound Derivation Reveals Prominent Mid-Frontal Alpha Associated with Neurosensory Dysfunction in Fragile X Syndrome. RESEARCH SQUARE 2023:rs.3.rs-2855646. [PMID: 37162907 PMCID: PMC10168472 DOI: 10.21203/rs.3.rs-2855646/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The FMR1 gene is inactive in Fragile X syndrome (FXS), resulting in low levels of FMRP and consequent neurochemical, synaptic, and local circuit neurophysiological alterations in the fmr1 KO mouse. In FXS patients, electrophysiological studies have demonstrated a marked reduction in global alpha activity and regional increases in gamma oscillations associated with intellectual disability and sensory hypersensitivity. Since alpha activity is associated with a thalamocortical function with widely distributed modulatory effects on neocortical excitability, insight into alpha physiology may provide insight into systems-level disease mechanisms. Herein, we took a data-driven approach to clarify the temporal and spatial properties of alpha and theta activity in participants with FXS. High-resolution resting-state EEG data were collected from participants affected by FXS (n = 65) and matched controls (n = 70). We used a multivariate technique to empirically classify neural oscillatory bands based on their coherent spatiotemporal patterns. Participants with FXS demonstrated: 1) redistribution of lower-frequency boundaries indicating a "slower" dominant alpha rhythm, 2) an anteriorization of alpha frequency activity, and 3) a correlation of increased individualized alpha power measurements with auditory neurosensory dysfunction. These findings suggest an important role for alterations in thalamocortical physiology for the well-established neocortical hyper-excitability in FXS and, thus, a role for neural systems level disruption to cortical hyperexcitability that has been studied primarily at the local circuit level in animal models.
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Affiliation(s)
| | | | | | | | | | - Rui Liu
- Cincinnati Children's Hospital Medical Center
| | | | | | - Steve W Wu
- Cincinnati Children's Hospital Medical Center
| | | | - Paul S Horn
- Cincinnati Children's Hospital Medical Center
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15
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Villa PA, Lainez NM, Jonak CR, Berlin SC, Ethell IM, Coss D. Altered GnRH neuron and ovarian innervation characterize reproductive dysfunction linked to the Fragile X messenger ribonucleoprotein ( Fmr1) gene mutation. Front Endocrinol (Lausanne) 2023; 14:1129534. [PMID: 36909303 PMCID: PMC9992745 DOI: 10.3389/fendo.2023.1129534] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/09/2023] [Indexed: 02/24/2023] Open
Abstract
Introduction Mutations in the Fragile X Messenger Ribonucleoprotein 1 (FMR1) gene cause Fragile X Syndrome, the most common monogenic cause of intellectual disability. Mutations of FMR1 are also associated with reproductive disorders, such as early cessation of reproductive function in females. While progress has been made in understanding the mechanisms of mental impairment, the causes of reproductive disorders are not clear. FMR1-associated reproductive disorders were studied exclusively from the endocrine perspective, while the FMR1 role in neurons that control reproduction was not addressed. Results Here, we demonstrate that similar to women with FMR1 mutations, female Fmr1 null mice stop reproducing early. However, young null females display larger litters, more corpora lutea in the ovaries, increased inhibin, progesterone, testosterone, and gonadotropin hormones in the circulation. Ovariectomy reveals both hypothalamic and ovarian contribution to elevated gonadotropins. Altered mRNA and protein levels of several synaptic molecules in the hypothalamus are identified, indicating reasons for hypothalamic dysregulation. Increased vascularization of corpora lutea, higher sympathetic innervation of growing follicles in the ovaries of Fmr1 nulls, and higher numbers of synaptic GABAA receptors in GnRH neurons, which are excitatory for GnRH neurons, contribute to increased FSH and LH, respectively. Unmodified and ovariectomized Fmr1 nulls have increased LH pulse frequency, suggesting that Fmr1 nulls exhibit hyperactive GnRH neurons, regardless of the ovarian feedback. Conclusion These results reveal Fmr1 function in the regulation of GnRH neuron secretion, and point to the role of GnRH neurons, in addition to the ovarian innervation, in the etiology of Fmr1-mediated reproductive disorders.
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Affiliation(s)
| | | | | | | | | | - Djurdjica Coss
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, United States
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16
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Abstract
The fragile X-related disorders are an important group of hereditary disorders that are caused by expanded CGG repeats in the 5' untranslated region of the FMR1 gene or by mutations in the coding sequence of this gene. Two categories of pathological CGG repeats are associated with these disorders, full mutation alleles and shorter premutation alleles. Individuals with full mutation alleles develop fragile X syndrome, which causes autism and intellectual disability, whereas those with premutation alleles, which have shorter CGG expansions, can develop fragile X-associated tremor/ataxia syndrome, a progressive neurodegenerative disease. Thus, fragile X-related disorders can manifest as neurodegenerative or neurodevelopmental disorders, depending on the size of the repeat expansion. Here, we review mouse models of fragile X-related disorders and discuss how they have informed our understanding of neurodegenerative and neurodevelopmental disorders. We also assess the translational value of these models for developing rational targeted therapies for intellectual disability and autism disorders.
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Affiliation(s)
- Rob Willemsen
- Department of Clinical Genetics, Erasmus University Medical Center, 3015 CN Rotterdam, the Netherlands. Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium
| | - R Frank Kooy
- Department of Clinical Genetics, Erasmus University Medical Center, 3015 CN Rotterdam, the Netherlands. Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium
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17
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Tempio A, Boulksibat A, Bardoni B, Delhaye S. Fragile X Syndrome as an interneuronopathy: a lesson for future studies and treatments. Front Neurosci 2023; 17:1171895. [PMID: 37188005 PMCID: PMC10176609 DOI: 10.3389/fnins.2023.1171895] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/05/2023] [Indexed: 05/17/2023] Open
Abstract
Fragile X Syndrome (FXS) is the most common form of inherited intellectual disability (ID) and a primary genetic cause of autism spectrum disorder (ASD). FXS arises from the silencing of the FMR1 gene causing the lack of translation of its encoded protein, the Fragile X Messenger RibonucleoProtein (FMRP), an RNA-binding protein involved in translational control and in RNA transport along dendrites. Although a large effort during the last 20 years has been made to investigate the cellular roles of FMRP, no effective and specific therapeutic intervention is available to treat FXS. Many studies revealed a role for FMRP in shaping sensory circuits during developmental critical periods to affect proper neurodevelopment. Dendritic spine stability, branching and density abnormalities are part of the developmental delay observed in various FXS brain areas. In particular, cortical neuronal networks in FXS are hyper-responsive and hyperexcitable, making these circuits highly synchronous. Overall, these data suggest that the excitatory/inhibitory (E/I) balance in FXS neuronal circuitry is altered. However, not much is known about how interneuron populations contribute to the unbalanced E/I ratio in FXS even if their abnormal functioning has an impact on the behavioral deficits of patients and animal models affected by neurodevelopmental disorders. We revise here the key literature concerning the role of interneurons in FXS not only with the purpose to better understand the pathophysiology of this disorder, but also to explore new possible therapeutic applications to treat FXS and other forms of ASD or ID. Indeed, for instance, the re-introduction of functional interneurons in the diseased brains has been proposed as a promising therapeutic approach for neurological and psychiatric disorders.
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Affiliation(s)
- Alessandra Tempio
- Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
- Alessandra Tempio,
| | - Asma Boulksibat
- Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Barbara Bardoni
- Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
- Inserm, Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
- *Correspondence: Barbara Bardoni,
| | - Sébastien Delhaye
- Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
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18
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Saraf TS, McGlynn RP, Bhatavdekar OM, Booth RG, Canal CE. FPT, a 2-Aminotetralin, Is a Potent Serotonin 5-HT 1A, 5-HT 1B, and 5-HT 1D Receptor Agonist That Modulates Cortical Electroencephalogram Activity in Adult Fmr1 Knockout Mice. ACS Chem Neurosci 2022; 13:3629-3640. [PMID: 36473166 PMCID: PMC10364582 DOI: 10.1021/acschemneuro.2c00574] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
There are no approved medicines for fragile X syndrome (FXS), a monogenic, neurodevelopmental disorder. Electroencephalogram (EEG) studies show alterations in resting-state cortical EEG spectra, such as increased gamma-band power, in patients with FXS that are also observed in Fmr1 knockout models of FXS, offering putative biomarkers for drug discovery. Genes encoding serotonin receptors (5-HTRs), including 5-HT1A, 5-HT1B, and 5-HT1DRs, are differentially expressed in FXS, providing a rationale for investigating them as pharmacotherapeutic targets. Previously we reported pharmacological activity and preclinical neurotherapeutic effects in Fmr1 knockout mice of an orally active 2-aminotetralin, (S)-5-(2'-fluorophenyl)-N,N-dimethyl-1,2,3,4-tetrahydronaphthalen-2-amine (FPT). FPT is a potent (low nM), high-efficacy partial agonist at 5-HT1ARs and a potent, low-efficacy partial agonist at 5-HT7Rs. Here we report new observations that FPT also has potent and efficacious agonist activity at human 5-HT1B and 5-HT1DRs. FPT's Ki values at 5-HT1B and 5-HT1DRs were <5 nM, but it had nil activity (>10 μM Ki) at 5-HT1FRs. We tested the effects of FPT (5.6 mg/kg, subcutaneous) on EEG recorded above the somatosensory and auditory cortices in freely moving, adult Fmr1 knockout and control mice. Consistent with previous reports, we observed significantly increased relative gamma power in untreated or vehicle-treated male and female Fmr1 knockout mice from recordings above the left somatosensory cortex (LSSC). In addition, we observed sex effects on EEG power. FPT did not eliminate the genotype difference in relative gamma power from the LSSC. FPT, however, robustly decreased relative alpha power in the LSSC and auditory cortex, with more pronounced effects in Fmr1 KO mice. Similarly, FPT decreased relative alpha power in the right SSC but only in Fmr1 knockout mice. FPT also increased relative delta power, with more pronounced effects in Fmr1 KO mice and caused small but significant increases in relative beta power. Distinct impacts of FPT on cortical EEG were like effects caused by certain FDA-approved psychotropic medications (including baclofen, allopregnanolone, and clozapine). These results advance the understanding of FPT's pharmacological and neurophysiological effects.
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Affiliation(s)
- Tanishka S Saraf
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, 3001 Mercer University Drive, Atlanta, Georgia 30341, United States
| | - Ryan P McGlynn
- Center for Drug Discovery, Department of Pharmaceutical Sciences, and Department of Chemistry and Chemical Biology, Northeastern University, 300 Huntington Street, Boston, Massachusetts 02115, United States
| | - Omkar M Bhatavdekar
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, 3400 North Charles Street, Croft Hall B27, Baltimore, Maryland 21218, United States
| | - Raymond G Booth
- Center for Drug Discovery, Department of Pharmaceutical Sciences, and Department of Chemistry and Chemical Biology, Northeastern University, 300 Huntington Street, Boston, Massachusetts 02115, United States
| | - Clinton E Canal
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, 3001 Mercer University Drive, Atlanta, Georgia 30341, United States
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19
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Wilde M, Constantin L, Thorne PR, Montgomery JM, Scott EK, Cheyne JE. Auditory processing in rodent models of autism: a systematic review. J Neurodev Disord 2022; 14:48. [PMID: 36042393 PMCID: PMC9429780 DOI: 10.1186/s11689-022-09458-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 08/07/2022] [Indexed: 11/19/2022] Open
Abstract
Autism is a complex condition with many traits, including differences in auditory sensitivity. Studies in human autism are plagued by the difficulty of controlling for aetiology, whereas studies in individual rodent models cannot represent the full spectrum of human autism. This systematic review compares results in auditory studies across a wide range of established rodent models of autism to mimic the wide range of aetiologies in the human population. A search was conducted in the PubMed and Web of Science databases to find primary research articles in mouse or rat models of autism which investigate central auditory processing. A total of 88 studies were included. These used non-invasive measures of auditory function, such as auditory brainstem response recordings, cortical event-related potentials, electroencephalography, and behavioural tests, which are translatable to human studies. They also included invasive measures, such as electrophysiology and histology, which shed insight on the origins of the phenotypes found in the non-invasive studies. The most consistent results across these studies were increased latency of the N1 peak of event-related potentials, decreased power and coherence of gamma activity in the auditory cortex, and increased auditory startle responses to high sound levels. Invasive studies indicated loss of subcortical inhibitory neurons, hyperactivity in the lateral superior olive and auditory thalamus, and reduced specificity of responses in the auditory cortex. This review compares the auditory phenotypes across rodent models and highlights those that mimic findings in human studies, providing a framework and avenues for future studies to inform understanding of the auditory system in autism.
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Affiliation(s)
- Maya Wilde
- The Queensland Brain Institute, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Lena Constantin
- The Queensland Brain Institute, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Peter R Thorne
- Department of Physiology, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand.,Section of Audiology, School of Population Health, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Ethan K Scott
- The Queensland Brain Institute, The University of Queensland, Brisbane, QLD, 4072, Australia.,Department of Anatomy and Physiology, School of Biomedical Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Juliette E Cheyne
- Department of Physiology, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand.
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20
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SARM1 deletion in parvalbumin neurons is associated with autism-like behaviors in mice. Cell Death Dis 2022; 13:638. [PMID: 35869039 PMCID: PMC9307765 DOI: 10.1038/s41419-022-05083-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 07/06/2022] [Accepted: 07/07/2022] [Indexed: 01/21/2023]
Abstract
Autism spectrum disorder (ASD), a group of neurodevelopmental disorder diseases, is characterized by social deficits, communication difficulties, and repetitive behaviors. Sterile alpha and TIR motif-containing 1 protein (SARM1) is known as an autism-associated protein and is enriched in brain tissue. Moreover, SARM1 knockdown mice exhibit autism-like behaviors. However, its specific mechanism in ASD pathogenesis remains unclear. Here we generated parvalbumin-positive interneurons (PVI)-specific conditional SARM1 knockout (SARM1PV-CKO) mice. SARM1PV-CKO male mice showed autism-like behaviors, such as mild social interaction deficits and repetitive behaviors. Moreover, we found that the expression level of parvalbumin was reduced in SARM1PV-CKO male mice, together with upregulated apoptosis-related proteins and more cleaved-caspase-3-positive PVIs, suggesting that knocking out SARM1 may cause a reduction in the number of PVIs due to apoptosis. Furthermore, the expression of c-fos was shown to increase in SARM1PV-CKO male mice, in combination with upregulation of excitatory postsynaptic proteins such as PSD-95 or neuroligin-1, indicating enhanced excitatory synaptic input in mutant mice. This notion was further supported by the partial rescue of autism-like behavior deficits by the administration of GABA receptor agonists in SARM1PV-CKO male mice. In conclusion, our findings suggest that SARM1 deficiency in PVIs may be involved in the pathogenesis of ASD.
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21
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Kalinowska M, van der Lei MB, Kitiashvili M, Mamcarz M, Oliveira MM, Longo F, Klann E. Deletion of Fmr1 in parvalbumin-expressing neurons results in dysregulated translation and selective behavioral deficits associated with fragile X syndrome. Mol Autism 2022; 13:29. [PMID: 35768828 PMCID: PMC9245312 DOI: 10.1186/s13229-022-00509-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 06/10/2022] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Fragile X syndrome (FXS), the most common genetic cause of autism spectrum disorder and intellectual disability, is caused by the lack of fragile X mental retardation protein (FMRP) expression. FMRP is an mRNA binding protein with functions in mRNA transport, localization, and translational control. In Fmr1 knockout mice, dysregulated translation has been linked to pathophysiology, including abnormal synaptic function and dendritic morphology, and autistic-like behavioral phenotypes. The role of FMRP in morphology and function of excitatory neurons has been well studied in mice lacking Fmr1, but the impact of Fmr1 deletion on inhibitory neurons remains less characterized. Moreover, the contribution of FMRP in different cell types to FXS pathophysiology is not well defined. We sought to characterize whether FMRP loss in parvalbumin or somatostatin-expressing neurons results in FXS-like deficits in mice. METHODS We used Cre-lox recombinase technology to generate two lines of conditional knockout mice lacking FMRP in either parvalbumin or somatostatin-expressing cells and carried out a battery of behavioral tests to assess motor function, anxiety, repetitive, stereotypic, social behaviors, and learning and memory. In addition, we used fluorescent non-canonical amino acid tagging along with immunostaining to determine whether de novo protein synthesis is dysregulated in parvalbumin or somatostatin-expressing neurons. RESULTS De novo protein synthesis was elevated in hippocampal parvalbumin and somatostatin-expressing inhibitory neurons in Fmr1 knockout mice. Cell type-specific deletion of Fmr1 in parvalbumin-expressing neurons resulted in anxiety-like behavior, impaired social behavior, and dysregulated de novo protein synthesis. In contrast, deletion of Fmr1 in somatostatin-expressing neurons did not result in behavioral abnormalities and did not significantly impact de novo protein synthesis. This is the first report of how loss of FMRP in two specific subtypes of inhibitory neurons is associated with distinct FXS-like abnormalities. LIMITATIONS The mouse models we generated are limited by whole body knockout of FMRP in parvalbumin or somatostatin-expressing cells and further studies are needed to establish a causal relationship between cellular deficits and FXS-like behaviors. CONCLUSIONS Our findings indicate a cell type-specific role for FMRP in parvalbumin-expressing neurons in regulating distinct behavioral features associated with FXS.
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Affiliation(s)
- Magdalena Kalinowska
- grid.137628.90000 0004 1936 8753Center for Neural Science, New York University, New York, NY USA
| | - Mathijs B. van der Lei
- grid.5284.b0000 0001 0790 3681Department of Medical Genetics, University of Antwerp, Antwerp, Belgium
| | - Michael Kitiashvili
- grid.137628.90000 0004 1936 8753Center for Neural Science, New York University, New York, NY USA
| | - Maggie Mamcarz
- grid.137628.90000 0004 1936 8753Center for Neural Science, New York University, New York, NY USA
| | - Mauricio M. Oliveira
- grid.137628.90000 0004 1936 8753Center for Neural Science, New York University, New York, NY USA
| | - Francesco Longo
- grid.8761.80000 0000 9919 9582Institute for Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden ,grid.8761.80000 0000 9919 9582Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY, USA. .,NYU Neuroscience Institute, New York University Langone Medical Center, New York, NY, USA.
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22
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Bülow P, Segal M, Bassell GJ. Mechanisms Driving the Emergence of Neuronal Hyperexcitability in Fragile X Syndrome. Int J Mol Sci 2022; 23:ijms23116315. [PMID: 35682993 PMCID: PMC9181819 DOI: 10.3390/ijms23116315] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/24/2022] [Accepted: 05/27/2022] [Indexed: 02/04/2023] Open
Abstract
Hyperexcitability is a shared neurophysiological phenotype across various genetic neurodevelopmental disorders, including Fragile X syndrome (FXS). Several patient symptoms are associated with hyperexcitability, but a puzzling feature is that their onset is often delayed until their second and third year of life. It remains unclear how and why hyperexcitability emerges in neurodevelopmental disorders. FXS is caused by the loss of FMRP, an RNA-binding protein which has many critical roles including protein synthesis-dependent and independent regulation of ion channels and receptors, as well as global regulation of protein synthesis. Here, we discussed recent literature uncovering novel mechanisms that may drive the progressive onset of hyperexcitability in the FXS brain. We discussed in detail how recent publications have highlighted defects in homeostatic plasticity, providing new insight on the FXS brain and suggest pharmacotherapeutic strategies in FXS and other neurodevelopmental disorders.
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Affiliation(s)
- Pernille Bülow
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Correspondence: (P.B.); (G.J.B.)
| | - Menahem Segal
- Department of Brain Science, Weizmann Institute of Science, Rehovot 76100, Israel;
| | - Gary J. Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Correspondence: (P.B.); (G.J.B.)
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23
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Holley A, Shedd A, Boggs A, Lovelace J, Erickson C, Gross C, Jankovic M, Razak K, Huber K, Gibson JR. A sound-driven cortical phase-locking change in the Fmr1 KO mouse requires Fmr1 deletion in a subpopulation of brainstem neurons. Neurobiol Dis 2022; 170:105767. [PMID: 35588990 PMCID: PMC9273231 DOI: 10.1016/j.nbd.2022.105767] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 04/27/2022] [Accepted: 05/11/2022] [Indexed: 11/30/2022] Open
Abstract
Background: Sensory impairments commonly occur in patients with autism or intellectual disability. Fragile X syndrome (FXS) is one form of intellectual disability that is often comorbid with autism. In electroencephalographic (EEG) recordings obtained from humans with FXS, the ability of cortical regions to consistently synchronize, or “phase-lock”, to modulated auditory stimuli is reduced compared to that of typically developing individuals. At the same time, less time-locked, “non-phase-locked” power induced by sounds is higher. The same changes occur in the Fmr1 knockout (KO) mouse – an animal model of FXS. We determined if Fmr1 deletion in a subset of brainstem auditory neurons plays any role in these EEG changes in the mouse. Methods: We reinstated FMRP expression in a subpopulation of brainstem auditory neurons in an otherwise Fmr1 KO control (conditional on; cON Fmr1) mouse and used EEG recordings to determine if reinstatement normalized, or “rescued”, the phase-locking phenotype observed in the cON Fmr1 mouse. In determining rescue, this also meant that Fmr1 deletion in the same neuron population was necessary for the phenotype to occur. Results: We find that Fmr1 reinstatement in a subset of brainstem neurons rescues certain aspects of the phase-locking phenotype but does not rescue the increase in non-phase-locked power. Unexpectedly, not all electrophysiological phenotypes observed in the Fmr1 KO were observed in the cON Fmr1 mouse used for the reinstatement experiments, and this was likely due to residual expression of FMRP in these Fmr1 KO controls. Conclusions: Fmr1 deletion in brainstem neurons is necessary for certain aspects of the decreased phase-locking phenotype in the Fmr1 KO, but not necessary for the increase in non-phase-locked power induced by a sound. The most likely brainstem structure underlying these results is the inferior colliculus. We also demonstrate that low levels of FMRP can rescue some EEG phenotypes but not others. This latter finding provides a foundation for how symptoms in FXS individuals may vary due to FMRP levels and that reinstatement of low FMRP levels may be sufficient to alleviate particular symptoms.
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Affiliation(s)
- AndrewJ Holley
- University of Texas Southwestern Medical Center at Dallas, Department of Neuroscience, Dallas, TX 75390-9111, USA
| | - Aleya Shedd
- University of Texas Southwestern Medical Center at Dallas, Department of Neuroscience, Dallas, TX 75390-9111, USA
| | - Anna Boggs
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Jonathan Lovelace
- Department of Psychology, University of California, Riverside, CA 92521, USA
| | - Craig Erickson
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Psychiatry, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Christina Gross
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Miranda Jankovic
- University of Texas Southwestern Medical Center at Dallas, Department of Neuroscience, Dallas, TX 75390-9111, USA
| | - Khaleel Razak
- Department of Psychology, University of California, Riverside, CA 92521, USA
| | - Kimberly Huber
- University of Texas Southwestern Medical Center at Dallas, Department of Neuroscience, Dallas, TX 75390-9111, USA
| | - Jay R Gibson
- University of Texas Southwestern Medical Center at Dallas, Department of Neuroscience, Dallas, TX 75390-9111, USA.
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Armstrong JL, Saraf TS, Bhatavdekar O, Canal CE. Spontaneous seizures in adult Fmr1 knockout mice: FVB.129P2-Pde6b+ Tyr Fmr1/J. Epilepsy Res 2022; 182:106891. [PMID: 35290907 PMCID: PMC9050957 DOI: 10.1016/j.eplepsyres.2022.106891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 02/14/2022] [Accepted: 02/17/2022] [Indexed: 01/26/2023]
Abstract
The prevalence of seizures in individuals with fragile X syndrome (FXS) is ~25%; however, there are no reports of spontaneous seizures in the Fmr1 knockout mouse model of FXS. Herein, we report that 48% of adult (median age P96), Fmr1 knockout mice from our colony were found expired in their home cages. We observed and recorded adult Fmr1 knockout mice having spontaneous convulsions in their home cages. In addition, we captured by electroencephalography an adult Fmr1 knockout mouse having a spontaneous seizure-during preictal, ictal, and postictal phases-which confirmed the presence of a generalized seizure. We did not observe this phenotype in control conspecifics or in juvenile (age <P35) Fmr1 knockout mice. We hypothesized that chronic, random, noise perturbations during development caused the phenotype. We recorded decibels (dB) in our vivarium. The average was 61 dB, but operating the automatic door to the vivarium caused spikes to 95 dB. We modified the door to eliminate noise spikes, which reduced unexpected deaths to 33% in Fmr1 knockout mice raised from birth in this environment (P = 0.07). As the modifications did not eliminate unexpected deaths, we further hypothesized that building vibrations may also be a contributing factor. After installing anti-vibration pads underneath housing carts, unexpected deaths of Fmr1 knockout mice born and raised in this environment decreased to 29% (P < 0.01 compared to the original environment). We also observed significant sex effects, for example, after interventions to reduce sound and vibration, significantly fewer male, but not female, Fmr1 knockout mice died unexpectedly (P < 0.001). The spontaneous seizure phenotype in our Fmr1 knockout mice could serve as a model of seizures observed in individuals with FXS, potentially offering a new translationally-valid phenotype for FXS research. Finally, these observations, although anomalous, serve as a reminder to consider gene-environment interactions when interpreting data derived from Fmr1 knockout mice.
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Affiliation(s)
- Jessica L Armstrong
- Mercer University, College of Pharmacy, Department of Pharmaceutical Sciences, 3001 Mercer University Drive, Atlanta, GA 30341, USA
| | - Tanishka S Saraf
- Mercer University, College of Pharmacy, Department of Pharmaceutical Sciences, 3001 Mercer University Drive, Atlanta, GA 30341, USA
| | - Omkar Bhatavdekar
- Johns Hopkins University, Department of Chemical and Biomolecular Engineering, 3400 North Charles Street, Croft Hall B27, Baltimore, MD 21218, USA
| | - Clinton E Canal
- Mercer University, College of Pharmacy, Department of Pharmaceutical Sciences, 3001 Mercer University Drive, Atlanta, GA 30341, USA.
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Castro AC, Monteiro P. Auditory Dysfunction in Animal Models of Autism Spectrum Disorder. Front Mol Neurosci 2022; 15:845155. [PMID: 35493332 PMCID: PMC9043325 DOI: 10.3389/fnmol.2022.845155] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 03/17/2022] [Indexed: 11/16/2022] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder mainly characterized by social-communication impairments, repetitive behaviors and altered sensory perception. Auditory hypersensitivity is the most common sensory-perceptual abnormality in ASD, however, its underlying neurobiological mechanisms remain elusive. Consistently with reports in ASD patients, animal models for ASD present sensory-perception alterations, including auditory processing impairments. Here we review the current knowledge regarding auditory dysfunction in rodent models of ASD, exploring both shared and distinct features among them, mechanistic and molecular underpinnings, and potential therapeutic approaches. Overall, auditory dysfunction in ASD models seems to arise from impaired central processing. Depending on the model, impairments may arise at different steps along the auditory pathway, from auditory brainstem up to the auditory cortex. Common defects found across models encompass atypical tonotopicity in different regions of the auditory pathway, temporal and spectral processing impairments and histological differences. Imbalance between excitation and inhibition (E/I imbalance) is one of the most well-supported mechanisms explaining the auditory phenotype in the ASD models studied so far and seems to be linked to alterations in GABAergic signaling. Such E/I imbalance may have a large impact on the development of the auditory pathway, influencing the establishment of connections responsible for normal sound processing.
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Affiliation(s)
- Ana Carolina Castro
- Life and Health Sciences Research Institute, School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s–PT Government Associate Laboratory, Braga, Portugal
| | - Patricia Monteiro
- Life and Health Sciences Research Institute, School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s–PT Government Associate Laboratory, Braga, Portugal
- *Correspondence: Patricia Monteiro,
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D’Incal C, Broos J, Torfs T, Kooy RF, Vanden Berghe W. Towards Kinase Inhibitor Therapies for Fragile X Syndrome: Tweaking Twists in the Autism Spectrum Kinase Signaling Network. Cells 2022; 11:cells11081325. [PMID: 35456004 PMCID: PMC9029738 DOI: 10.3390/cells11081325] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/01/2022] [Accepted: 04/03/2022] [Indexed: 12/12/2022] Open
Abstract
Absence of the Fragile X Mental Retardation Protein (FMRP) causes autism spectrum disorders and intellectual disability, commonly referred to as the Fragile X syndrome. FMRP is a negative regulator of protein translation and is essential for neuronal development and synapse formation. FMRP is a target for several post-translational modifications (PTMs) such as phosphorylation and methylation, which tightly regulate its cellular functions. Studies have indicated the involvement of FMRP in a multitude of cellular pathways, and an absence of FMRP was shown to affect several neurotransmitter receptors, for example, the GABA receptor and intracellular signaling molecules such as Akt, ERK, mTOR, and GSK3. Interestingly, many of these molecules function as protein kinases or phosphatases and thus are potentially amendable by pharmacological treatment. Several treatments acting on these kinase-phosphatase systems have been shown to be successful in preclinical models; however, they have failed to convincingly show any improvements in clinical trials. In this review, we highlight the different protein kinase and phosphatase studies that have been performed in the Fragile X syndrome. In our opinion, some of the paradoxical study conclusions are potentially due to the lack of insight into integrative kinase signaling networks in the disease. Quantitative proteome analyses have been performed in several models for the FXS to determine global molecular processes in FXS. However, only one phosphoproteomics study has been carried out in Fmr1 knock-out mouse embryonic fibroblasts, and it showed dysfunctional protein kinase and phosphatase signaling hubs in the brain. This suggests that the further use of phosphoproteomics approaches in Fragile X syndrome holds promise for identifying novel targets for kinase inhibitor therapies.
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Affiliation(s)
- Claudio D’Incal
- Protein Chemistry, Proteomics and Epigenetic Signaling (PPES), Department of Biomedical Sciences, University of Antwerp, 2000 Antwerp, Belgium; (C.D.); (J.B.); (T.T.)
- Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium;
| | - Jitse Broos
- Protein Chemistry, Proteomics and Epigenetic Signaling (PPES), Department of Biomedical Sciences, University of Antwerp, 2000 Antwerp, Belgium; (C.D.); (J.B.); (T.T.)
| | - Thierry Torfs
- Protein Chemistry, Proteomics and Epigenetic Signaling (PPES), Department of Biomedical Sciences, University of Antwerp, 2000 Antwerp, Belgium; (C.D.); (J.B.); (T.T.)
| | - R. Frank Kooy
- Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium;
| | - Wim Vanden Berghe
- Protein Chemistry, Proteomics and Epigenetic Signaling (PPES), Department of Biomedical Sciences, University of Antwerp, 2000 Antwerp, Belgium; (C.D.); (J.B.); (T.T.)
- Correspondence: ; Tel.: +0032-(0)-32-652-657
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Kenny A, Wright D, Stanfield AC. EEG as a translational biomarker and outcome measure in fragile X syndrome. Transl Psychiatry 2022; 12:34. [PMID: 35075104 PMCID: PMC8786970 DOI: 10.1038/s41398-022-01796-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 12/01/2021] [Accepted: 01/12/2022] [Indexed: 01/08/2023] Open
Abstract
Targeted treatments for fragile X syndrome (FXS) have frequently failed to show efficacy in clinical testing, despite success at the preclinical stages. This has highlighted the need for more effective translational outcome measures. EEG differences observed in FXS, including exaggerated N1 ERP amplitudes, increased resting gamma power and reduced gamma phase-locking in the sensory cortices, have been suggested as potential biomarkers of the syndrome. These abnormalities are thought to reflect cortical hyper excitability resulting from an excitatory (glutamate) and inhibitory (GABAergic) imbalance in FXS, which has been the target of several pharmaceutical remediation studies. EEG differences observed in humans also show similarities to those seen in laboratory models of FXS, which may allow for greater translational equivalence and better predict clinical success of putative therapeutics. There is some evidence from clinical trials showing that treatment related changes in EEG may be associated with clinical improvements, but these require replication and extension to other medications. Although the use of EEG characteristics as biomarkers is still in the early phases, and further research is needed to establish its utility in clinical trials, the current research is promising and signals the emergence of an effective translational biomarker.
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Affiliation(s)
- Aisling Kenny
- Patrick Wild Centre, Division of Psychiatry, Kennedy Tower, Royal Edinburgh Hospital, University of Edinburgh, EH10 5HF, Edinburgh, UK.
| | - Damien Wright
- grid.4305.20000 0004 1936 7988Patrick Wild Centre, Division of Psychiatry, Kennedy Tower, Royal Edinburgh Hospital, University of Edinburgh, EH10 5HF Edinburgh, UK
| | - Andrew C. Stanfield
- grid.4305.20000 0004 1936 7988Patrick Wild Centre, Division of Psychiatry, Kennedy Tower, Royal Edinburgh Hospital, University of Edinburgh, EH10 5HF Edinburgh, UK
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Chawla A, McCullagh EA. Auditory Brain Stem Responses in the C57BL/6J Fragile X Syndrome-Knockout Mouse Model. Front Integr Neurosci 2022; 15:803483. [PMID: 35111002 PMCID: PMC8802689 DOI: 10.3389/fnint.2021.803483] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 12/14/2021] [Indexed: 01/07/2023] Open
Abstract
Sensory hypersensitivity, especially in the auditory system, is a common symptom in Fragile X syndrome (FXS), the most common monogenic form of intellectual disability. However, linking phenotypes across genetic background strains of mouse models has been a challenge and could underly some of the issues with translatability of drug studies to the human condition. This study is the first to characterize the auditory brain stem response (ABR), a minimally invasive physiological readout of early auditory processing that is also used in humans, in a commonly used mouse background strain model of FXS, C57BL/6J. We measured morphological features of pinna and head and used ABR to measure the hearing range, and monaural and binaural auditory responses in hemizygous males, homozygous females, and heterozygous females compared with those in wild-type mice. Consistent with previous study, we showed no difference in morphological parameters across genotypes or sexes. There was no significant difference in hearing range between the sexes or genotypes, however there was a trend towards high frequency hearing loss in male FXS mice. In contrast, female mice with homozygous FXS had a decreased amplitude of wave IV of the monaural ABR, while there was no difference in males for amplitudes and no change in latency of ABR waveforms across sexes and genotypes. Finally, males with FXS had an increased latency of the binaural interaction component (BIC) at 0 interaural timing difference compared with that in wild-type males. These findings further clarify auditory brain stem processing in FXS by adding more information across genetic background strains allowing for a better understanding of shared phenotypes.
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Liu X, Kumar V, Tsai NP, Auerbach BD. Hyperexcitability and Homeostasis in Fragile X Syndrome. Front Mol Neurosci 2022; 14:805929. [PMID: 35069112 PMCID: PMC8770333 DOI: 10.3389/fnmol.2021.805929] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 12/14/2021] [Indexed: 01/13/2023] Open
Abstract
Fragile X Syndrome (FXS) is a leading inherited cause of autism and intellectual disability, resulting from a mutation in the FMR1 gene and subsequent loss of its protein product FMRP. Despite this simple genetic origin, FXS is a phenotypically complex disorder with a range of physical and neurocognitive disruptions. While numerous molecular and cellular pathways are affected by FMRP loss, there is growing evidence that circuit hyperexcitability may be a common convergence point that can account for many of the wide-ranging phenotypes seen in FXS. The mechanisms for hyperexcitability in FXS include alterations to excitatory synaptic function and connectivity, reduced inhibitory neuron activity, as well as changes to ion channel expression and conductance. However, understanding the impact of FMR1 mutation on circuit function is complicated by the inherent plasticity in neural circuits, which display an array of homeostatic mechanisms to maintain activity near set levels. FMRP is also an important regulator of activity-dependent plasticity in the brain, meaning that dysregulated plasticity can be both a cause and consequence of hyperexcitable networks in FXS. This makes it difficult to separate the direct effects of FMR1 mutation from the myriad and pleiotropic compensatory changes associated with it, both of which are likely to contribute to FXS pathophysiology. Here we will: (1) review evidence for hyperexcitability and homeostatic plasticity phenotypes in FXS models, focusing on similarities/differences across brain regions, cell-types, and developmental time points; (2) examine how excitability and plasticity disruptions interact with each other to ultimately contribute to circuit dysfunction in FXS; and (3) discuss how these synaptic and circuit deficits contribute to disease-relevant behavioral phenotypes like epilepsy and sensory hypersensitivity. Through this discussion of where the current field stands, we aim to introduce perspectives moving forward in FXS research.
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Affiliation(s)
- Xiaopeng Liu
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Beckman Institute for Advanced Science & Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Vipendra Kumar
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Nien-Pei Tsai
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Benjamin D. Auerbach
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Beckman Institute for Advanced Science & Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- *Correspondence: Benjamin D. Auerbach
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30
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Rais M, Lovelace JW, Shuai XS, Woodard W, Bishay S, Estrada L, Sharma AR, Nguy A, Kulinich A, Pirbhoy PS, Palacios AR, Nelson DL, Razak KA, Ethell IM. Functional consequences of postnatal interventions in a mouse model of Fragile X syndrome. Neurobiol Dis 2021; 162:105577. [PMID: 34871737 DOI: 10.1016/j.nbd.2021.105577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 10/22/2021] [Accepted: 12/02/2021] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Fragile X syndrome (FXS) is a leading genetic cause of autism and intellectual disability with cortical hyperexcitability and sensory hypersensitivity attributed to loss and hypofunction of inhibitory parvalbumin-expressing (PV) cells. Our studies provide novel insights into the role of excitatory neurons in abnormal development of PV cells during a postnatal period of inhibitory circuit refinement. METHODS To achieve Fragile X mental retardation gene (Fmr1) deletion and re-expression in excitatory neurons during the postnatal day (P)14-P21 period, we generated CreCaMKIIa/Fmr1Flox/y (cOFF) and CreCaMKIIa/Fmr1FloxNeo/y (cON) mice, respectively. Cortical phenotypes were evaluated in adult mice using biochemical, cellular, clinically relevant electroencephalogram (EEG) and behavioral tests. RESULTS We found that similar to global Fmr1 KO mice, the density of PV-expressing cells, their activation, and sound-evoked gamma synchronization were impaired in cOFF mice, but the phenotypes were improved in cON mice. cOFF mice also showed enhanced cortical gelatinase activity and baseline EEG gamma power, which were reduced in cON mice. In addition, TrkB phosphorylation and PV levels were lower in cOFF mice, which also showed increased locomotor activity and anxiety-like behaviors. Remarkably, when FMRP levels were restored in only excitatory neurons during the P14-P21 period, TrkB phosphorylation and mouse behaviors were also improved. CONCLUSIONS These results indicate that postnatal deletion or re-expression of FMRP in excitatory neurons is sufficient to elicit or ameliorate structural and functional cortical deficits, and abnormal behaviors in mice, informing future studies about appropriate treatment windows and providing fundamental insights into the cellular mechanisms of cortical circuit dysfunction in FXS.
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Affiliation(s)
- Maham Rais
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, CA 92521, USA
| | - Jonathan W Lovelace
- Department of Psychology, University of California Riverside, Riverside, CA 92521, USA
| | - Xinghao S Shuai
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, CA 92521, USA
| | - Walker Woodard
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, CA 92521, USA
| | - Steven Bishay
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, CA 92521, USA
| | - Leo Estrada
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, CA 92521, USA
| | - Ashwin R Sharma
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, CA 92521, USA
| | - Austin Nguy
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, CA 92521, USA
| | - Anna Kulinich
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, CA 92521, USA
| | - Patricia S Pirbhoy
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, CA 92521, USA
| | - Arnold R Palacios
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, CA 92521, USA
| | | | - Khaleel A Razak
- Department of Psychology, University of California Riverside, Riverside, CA 92521, USA; Neuroscience Graduate Program, University of California Riverside, Riverside, CA 92521, USA
| | - Iryna M Ethell
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, CA 92521, USA; Neuroscience Graduate Program, University of California Riverside, Riverside, CA 92521, USA.
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31
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Contractor A, Ethell IM, Portera-Cailliau C. Cortical interneurons in autism. Nat Neurosci 2021; 24:1648-1659. [PMID: 34848882 PMCID: PMC9798607 DOI: 10.1038/s41593-021-00967-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 09/21/2021] [Indexed: 01/01/2023]
Abstract
The mechanistic underpinnings of autism remain a subject of debate and controversy. Why do individuals with autism share an overlapping set of atypical behaviors and symptoms, despite having different genetic and environmental risk factors? A major challenge in developing new therapies for autism has been the inability to identify convergent neural phenotypes that could explain the common set of symptoms that result in the diagnosis. Although no striking macroscopic neuropathological changes have been identified in autism, there is growing evidence that inhibitory interneurons (INs) play an important role in its neural basis. In this Review, we evaluate and interpret this evidence, focusing on recent findings showing reduced density and activity of the parvalbumin class of INs. We discuss the need for additional studies that investigate how genes and the environment interact to change the developmental trajectory of INs, permanently altering their numbers, connectivity and circuit engagement.
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Affiliation(s)
- Anis Contractor
- Department of Neuroscience Feinberg School of Medicine, Weinberg College of Arts and Sciences, Northwestern University, Chicago, IL, USA.,Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Chicago, IL, USA
| | - Iryna M. Ethell
- Division of Biomedical Sciences, UC Riverside School of Medicine, Riverside, CA, USA
| | - Carlos Portera-Cailliau
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA. .,Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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32
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Pirbhoy PS, Jonak CR, Syed R, Argueta DA, Perez PA, Wiley MB, Hessamian K, Lovelace JW, Razak KA, DiPatrizio NV, Ethell IM, Binder DK. Increased 2-arachidonoyl-sn-glycerol levels normalize cortical responses to sound and improve behaviors in Fmr1 KO mice. J Neurodev Disord 2021; 13:47. [PMID: 34645383 PMCID: PMC8513313 DOI: 10.1186/s11689-021-09394-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 09/20/2021] [Indexed: 01/08/2023] Open
Abstract
Background Individuals with Fragile X syndrome (FXS) and autism spectrum disorder (ASD) exhibit an array of symptoms, including sociability deficits, increased anxiety, hyperactivity, and sensory hyperexcitability. It is unclear how endocannabinoid (eCB) modulation can be targeted to alleviate neurophysiological abnormalities in FXS as behavioral research reveals benefits to inhibiting cannabinoid (CB) receptor activation and increasing endocannabinoid ligand levels. Here, we hypothesize that enhancement of 2-arachidonoyl-sn-glycerol (2-AG) in Fragile X mental retardation 1 gene knock-out (Fmr1 KO) mice may reduce cortical hyperexcitability and behavioral abnormalities observed in FXS. Methods To test whether an increase in 2-AG levels normalized cortical responses in a mouse model of FXS, animals were subjected to electroencephalography (EEG) recording and behavioral assessment following treatment with JZL-184, an irreversible inhibitor of monoacylglycerol lipase (MAGL). Assessment of 2-AG was performed using lipidomic analysis in conjunction with various doses and time points post-administration of JZL-184. Baseline electrocortical activity and evoked responses to sound stimuli were measured using a 30-channel multielectrode array (MEA) in adult male mice before, 4 h, and 1 day post-intraperitoneal injection of JZL-184 or vehicle. Behavior assessment was done using the open field and elevated plus maze 4 h post-treatment. Results Lipidomic analysis showed that 8 mg/kg JZL-184 significantly increased the levels of 2-AG in the auditory cortex of both Fmr1 KO and WT mice 4 h post-treatment compared to vehicle controls. EEG recordings revealed a reduction in the abnormally enhanced baseline gamma-band power in Fmr1 KO mice and significantly improved evoked synchronization to auditory stimuli in the gamma-band range post-JZL-184 treatment. JZL-184 treatment also ameliorated anxiety-like and hyperactivity phenotypes in Fmr1 KO mice. Conclusions Overall, these results indicate that increasing 2-AG levels may serve as a potential therapeutic approach to normalize cortical responses and improve behavioral outcomes in FXS and possibly other ASDs. Supplementary Information The online version contains supplementary material available at 10.1186/s11689-021-09394-x.
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Affiliation(s)
- Patricia S Pirbhoy
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Carrie R Jonak
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Rashid Syed
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Donovan A Argueta
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Pedro A Perez
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Mark B Wiley
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Keon Hessamian
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Jonathan W Lovelace
- Department of Psychology, University of California, Riverside, Riverside, CA, 92521, USA
| | - Khaleel A Razak
- Department of Psychology, University of California, Riverside, Riverside, CA, 92521, USA
| | - Nicholas V DiPatrizio
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Iryna M Ethell
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA
| | - Devin K Binder
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, 92521, USA.
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33
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Razak KA, Binder DK, Ethell IM. Neural Correlates of Auditory Hypersensitivity in Fragile X Syndrome. Front Psychiatry 2021; 12:720752. [PMID: 34690832 PMCID: PMC8529206 DOI: 10.3389/fpsyt.2021.720752] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/16/2021] [Indexed: 01/20/2023] Open
Abstract
The mechanisms underlying the common association between autism spectrum disorders (ASD) and sensory processing disorders (SPD) are unclear, and treatment options to reduce atypical sensory processing are limited. Fragile X Syndrome (FXS) is a leading genetic cause of intellectual disability and ASD behaviors. As in most children with ASD, atypical sensory processing is a common symptom in FXS, frequently manifesting as sensory hypersensitivity. Auditory hypersensitivity is a highly debilitating condition in FXS that may lead to language delays, social anxiety and ritualized repetitive behaviors. Animal models of FXS, including Fmr1 knock out (KO) mouse, also show auditory hypersensitivity, providing a translation relevant platform to study underlying pathophysiological mechanisms. The focus of this review is to summarize recent studies in the Fmr1 KO mouse that identified neural correlates of auditory hypersensitivity. We review results of electroencephalography (EEG) recordings in the Fmr1 KO mice and highlight EEG phenotypes that are remarkably similar to EEG findings in humans with FXS. The EEG phenotypes associated with the loss of FMRP include enhanced resting EEG gamma band power, reduced cross frequency coupling, reduced sound-evoked synchrony of neural responses at gamma band frequencies, increased event-related potential amplitudes, reduced habituation of neural responses and increased non-phase locked power. In addition, we highlight the postnatal period when the EEG phenotypes develop and show a strong association of the phenotypes with enhanced matrix-metalloproteinase-9 (MMP-9) activity, abnormal development of parvalbumin (PV)-expressing inhibitory interneurons and reduced formation of specialized extracellular matrix structures called perineuronal nets (PNNs). Finally, we discuss how dysfunctions of inhibitory PV interneurons may contribute to cortical hyperexcitability and EEG abnormalities observed in FXS. Taken together, the studies reviewed here indicate that EEG recordings can be utilized in both pre-clinical studies and clinical trials, while at the same time, used to identify cellular and circuit mechanisms of dysfunction in FXS. New therapeutic approaches that reduce MMP-9 activity and restore functions of PV interneurons may succeed in reducing FXS sensory symptoms. Future studies should examine long-lasting benefits of developmental vs. adult interventions on sensory phenotypes.
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Affiliation(s)
- Khaleel A. Razak
- Department of Psychology, University of California, Riverside, Riverside, CA, United States
- Graduate Neuroscience Program, University of California, Riverside, Riverside, CA, United States
| | - Devin K. Binder
- Graduate Neuroscience Program, University of California, Riverside, Riverside, CA, United States
- Division of Biomedical Sciences and Graduate Biomedical Sciences Program, School of Medicine, University of California, Riverside, Riverside, CA, United States
| | - Iryna M. Ethell
- Graduate Neuroscience Program, University of California, Riverside, Riverside, CA, United States
- Division of Biomedical Sciences and Graduate Biomedical Sciences Program, School of Medicine, University of California, Riverside, Riverside, CA, United States
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Hooper AW, Wong H, Niibori Y, Abdoli R, Karumuthil-Melethil S, Qiao C, Danos O, Bruder JT, Hampson DR. Gene therapy using an ortholog of human fragile X mental retardation protein partially rescues behavioral abnormalities and EEG activity. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2021; 22:196-209. [PMID: 34485605 PMCID: PMC8399347 DOI: 10.1016/j.omtm.2021.06.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 06/30/2021] [Indexed: 01/28/2023]
Abstract
Fragile X syndrome (FXS), a neurodevelopmental disorder with no known cure, is caused by a lack of expression of the fragile X mental retardation protein (FMRP). As a single-gene disorder, FXS is an excellent candidate for viral-vector-based gene therapy, although that is complicated by the existence of multiple isoforms of FMRP, whose individual cellular functions are unknown. We studied the effects of rat and mouse orthologs of human isoform 17, a major expressed isoform of FMRP. Injection of neonatal Fmr1 knockout rats and mice with adeno-associated viral vectors (AAV9 serotype) under the control of an MeCP2 mini-promoter resulted in widespread distribution of the FMRP transgenes throughout the telencephalon and diencephalon. Transgene expression occurred mainly in non-GABAergic neurons, with little expression in glia. Early postnatal treatment resulted in partial rescue of the Fmr1 KO rat phenotype, including improved social dominance in treated Fmr1 KO females and partial rescue of locomotor activity in males. Electro-encephalogram (EEG) recordings showed correction of abnormal slow-wave activity during the sleep-like state in male Fmr1 KO rats. These findings support the use of AAV-based gene therapy as a treatment for FXS and specifically demonstrate the potential therapeutic benefit of human FMRP isoform 17 orthologs.
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Affiliation(s)
- Alexander W.M. Hooper
- Leslie Dan Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada M5S 3M2
| | - Hayes Wong
- Leslie Dan Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada M5S 3M2
| | - Yosuke Niibori
- Leslie Dan Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada M5S 3M2
| | - Rozita Abdoli
- Leslie Dan Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada M5S 3M2
| | | | - Chunping Qiao
- Research and Early Development, REGENXBIO Inc. Rockville, Maryland, U.S.A. 20850
| | - Olivier Danos
- Research and Early Development, REGENXBIO Inc. Rockville, Maryland, U.S.A. 20850
| | - Joseph T. Bruder
- Research and Early Development, REGENXBIO Inc. Rockville, Maryland, U.S.A. 20850
| | - David R. Hampson
- Leslie Dan Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada M5S 3M2
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada M5S 3M2
- Corresponding author: David R. Hampson, PhD, Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, Univerity of Toronto, ON M5S 3M2, Canada.
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Booker SA, Kind PC. Mechanisms regulating input-output function and plasticity of neurons in the absence of FMRP. Brain Res Bull 2021; 175:69-80. [PMID: 34245842 DOI: 10.1016/j.brainresbull.2021.06.025] [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: 02/10/2021] [Revised: 06/13/2021] [Accepted: 06/29/2021] [Indexed: 12/12/2022]
Abstract
The function of brain circuits relies on high-fidelity information transfer within neurons. Synaptic inputs arrive primarily at dendrites, where they undergo integration and summation throughout the somatodendritic domain, ultimately leading to the generation of precise patterns of action potentials. Emerging evidence suggests that the ability of neurons to transfer synaptic information and modulate their output is impaired in a number of neurodevelopmental disorders including Fragile X Syndrome. In this review we summarise recent findings that have revealed the pathophysiological and plasticity mechanisms that alter the ability of neurons in sensory and limbic circuits to reliably code information in the absence of FMRP. We examine which aspects of this transform may result directly from the loss of FMRP and those that a result from compensatory or homeostatic alterations to neuronal function. Dissection of the mechanisms leading to altered input-output function of neurons in the absence of FMRP and their effects on regulating neuronal plasticity throughout development could have important implications for potential therapies for Fragile X Syndrome, including directing the timing and duration of different treatment options.
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Affiliation(s)
- Sam A Booker
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK; Patrick Wild Centre for Autism Research, University of Edinburgh, Edinburgh, UK; Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.
| | - Peter C Kind
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK; Patrick Wild Centre for Autism Research, University of Edinburgh, Edinburgh, UK; Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK; National Centre for Biological Sciences (NCBS), Bangalore, India.
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Mascio G, Bucci D, Notartomaso S, Liberatore F, Antenucci N, Scarselli P, Imbriglio T, Caruso S, Gradini R, Cannella M, Di Menna L, Bruno V, Battaglia G, Nicoletti F. Perineuronal nets are under the control of type-5 metabotropic glutamate receptors in the developing somatosensory cortex. Transl Psychiatry 2021; 11:109. [PMID: 33597513 PMCID: PMC7889908 DOI: 10.1038/s41398-021-01210-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 10/29/2020] [Accepted: 11/05/2020] [Indexed: 12/14/2022] Open
Abstract
mGlu5 metabotropic glutamate receptors are highly functional in the early postnatal life, and regulate developmental plasticity of parvalbumin-positive (PV+) interneurons in the cerebral cortex. PV+ cells are enwrapped by perineuronal nets (PNNs) at the closure of critical windows of cortical plasticity. Changes in PNNs have been associated with neurodevelopmental disorders. We found that the number of Wisteria Fluoribunda Agglutinin (WFA)+ PNNs and the density of WFA+/PV+ cells were largely increased in the somatosensory cortex of mGlu5-/- mice at PND16. An increased WFA+ PNN density was also observed after pharmacological blockade of mGlu5 receptors in the first two postnatal weeks. The number of WFA+ PNNs in mGlu5-/- mice was close to a plateau at PND16, whereas continued to increase in wild-type mice, and there was no difference between the two genotypes at PND21 and PND60. mGlu5-/- mice at PND16 showed increases in the transcripts of genes involved in PNN formation and a reduced expression and activity of type-9 matrix metalloproteinase in the somatosensory cortex suggesting that mGlu5 receptors control both PNN formation and degradation. Finally, unilateral whisker stimulation from PND9 to PND16 enhanced WFA+ PNN density in the contralateral somatosensory cortex only in mGlu5+/+ mice, whereas whisker trimming from PND9 to PND16 reduced WFA+ PNN density exclusively in mGlu5-/- mice, suggesting that mGlu5 receptors shape the PNN response to sensory experience. These findings disclose a novel undescribed mechanism of PNN regulation, and lay the groundwork for the study of mGlu5 receptors and PNNs in neurodevelopmental disorders.
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Affiliation(s)
- Giada Mascio
- grid.419543.e0000 0004 1760 3561IRCCS Neuromed, Pozzilli, Italy
| | - Domenico Bucci
- grid.419543.e0000 0004 1760 3561IRCCS Neuromed, Pozzilli, Italy
| | | | | | - Nico Antenucci
- grid.7841.aDepartment of Physiology and Pharmacology, Sapienza University, Rome, Italy
| | | | | | - Stefano Caruso
- grid.7841.aDepartment of Physiology and Pharmacology, Sapienza University, Rome, Italy
| | - Roberto Gradini
- grid.7841.aDepartment of Experimental Medicine, Sapienza University, Rome, Italy
| | - Milena Cannella
- grid.419543.e0000 0004 1760 3561IRCCS Neuromed, Pozzilli, Italy
| | - Luisa Di Menna
- grid.419543.e0000 0004 1760 3561IRCCS Neuromed, Pozzilli, Italy
| | - Valeria Bruno
- grid.419543.e0000 0004 1760 3561IRCCS Neuromed, Pozzilli, Italy ,grid.7841.aDepartment of Physiology and Pharmacology, Sapienza University, Rome, Italy
| | - Giuseppe Battaglia
- grid.419543.e0000 0004 1760 3561IRCCS Neuromed, Pozzilli, Italy ,grid.7841.aDepartment of Physiology and Pharmacology, Sapienza University, Rome, Italy
| | - Ferdinando Nicoletti
- IRCCS Neuromed, Pozzilli, Italy. .,Department of Physiology and Pharmacology, Sapienza University, Rome, Italy.
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Williams ZJ, He JL, Cascio CJ, Woynaroski TG. A review of decreased sound tolerance in autism: Definitions, phenomenology, and potential mechanisms. Neurosci Biobehav Rev 2021; 121:1-17. [PMID: 33285160 PMCID: PMC7855558 DOI: 10.1016/j.neubiorev.2020.11.030] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 12/23/2022]
Abstract
Atypical behavioral responses to environmental sounds are common in autistic children and adults, with 50-70 % of this population exhibiting decreased sound tolerance (DST) at some point in their lives. This symptom is a source of significant distress and impairment across the lifespan, contributing to anxiety, challenging behaviors, reduced community participation, and school/workplace difficulties. However, relatively little is known about its phenomenology or neurocognitive underpinnings. The present article synthesizes a large body of literature on the phenomenology and pathophysiology of DST-related conditions to generate a comprehensive theoretical account of DST in autism. Notably, we argue against conceptualizing DST as a unified construct, suggesting that it be separated into three phenomenologically distinct conditions: hyperacusis (the perception of everyday sounds as excessively loud or painful), misophonia (an acquired aversive reaction to specific sounds), and phonophobia (a specific phobia of sound), each responsible for a portion of observed DST behaviors. We further elaborate our framework by proposing preliminary neurocognitive models of hyperacusis, misophonia, and phonophobia that incorporate neurophysiologic findings from studies of autism.
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Affiliation(s)
- Zachary J Williams
- Medical Scientist Training Program, Vanderbilt University School of Medicine, 221 Eskind Biomedical Library and Learning Center, 2209 Garland Ave., Nashville, TN, 37240, United States; Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, 1215 21st Avenue South, Medical Center East, Room 8310, Nashville, TN, 37232, United States; Vanderbilt Brain Institute, Vanderbilt University, 7203 Medical Research Building III, 465 21st Avenue South, Nashville, TN, 37232, United States; Frist Center for Autism and Innovation, Vanderbilt University, 2414 Highland Avenue, Suite 115, Nashville, TN, 37212, United States.
| | - Jason L He
- Department of Forensic and Neurodevelopmental Sciences, Sackler Institute for Translational Neurodevelopment, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Strand Building, Strand Campus, Strand, London, WC2R 2LS, London, United Kingdom.
| | - Carissa J Cascio
- Vanderbilt Brain Institute, Vanderbilt University, 7203 Medical Research Building III, 465 21st Avenue South, Nashville, TN, 37232, United States; Frist Center for Autism and Innovation, Vanderbilt University, 2414 Highland Avenue, Suite 115, Nashville, TN, 37212, United States; Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, 2254 Village at Vanderbilt, 1500 21st Ave South, Nashville, TN, 37212, United States; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, 110 Magnolia Cir, Nashville, TN, 37203, United States.
| | - Tiffany G Woynaroski
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, 1215 21st Avenue South, Medical Center East, Room 8310, Nashville, TN, 37232, United States; Vanderbilt Brain Institute, Vanderbilt University, 7203 Medical Research Building III, 465 21st Avenue South, Nashville, TN, 37232, United States; Frist Center for Autism and Innovation, Vanderbilt University, 2414 Highland Avenue, Suite 115, Nashville, TN, 37212, United States; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, 110 Magnolia Cir, Nashville, TN, 37203, United States.
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Neuron-Specific FMRP Roles in Experience-Dependent Remodeling of Olfactory Brain Innervation during an Early-Life Critical Period. J Neurosci 2021; 41:1218-1241. [PMID: 33402421 DOI: 10.1523/jneurosci.2167-20.2020] [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: 08/18/2020] [Revised: 12/04/2020] [Accepted: 12/08/2020] [Indexed: 01/12/2023] Open
Abstract
Critical periods are developmental windows during which neural circuits effectively adapt to the new sensory environment. Animal models of fragile X syndrome (FXS), a common monogenic autism spectrum disorder (ASD), exhibit profound impairments of sensory experience-driven critical periods. However, it is not known whether the causative fragile X mental retardation protein (FMRP) acts uniformly across neurons, or instead manifests neuron-specific functions. Here, we use the genetically-tractable Drosophila brain antennal lobe (AL) olfactory circuit of both sexes to investigate neuron-specific FMRP roles in the odorant experience-dependent remodeling of the olfactory sensory neuron (OSN) innervation during an early-life critical period. We find targeted OSN class-specific FMRP RNAi impairs innervation remodeling within AL synaptic glomeruli, whereas global dfmr1 null mutants display relatively normal odorant-driven refinement. We find both OSN cell autonomous and cell non-autonomous FMRP functions mediate odorant experience-dependent remodeling, with AL circuit FMRP imbalance causing defects in overall glomerulus innervation refinement. We find OSN class-specific FMRP levels bidirectionally regulate critical period remodeling, with odorant experience selectively controlling OSN synaptic terminals in AL glomeruli. We find OSN class-specific FMRP loss impairs critical period remodeling by disrupting responses to lateral modulation from other odorant-responsive OSNs mediating overall AL gain control. We find that silencing glutamatergic AL interneurons reduces OSN remodeling, while conversely, interfering with the OSN class-specific GABAA signaling enhances remodeling. These findings reveal control of OSN synaptic remodeling by FMRP with neuron-specific circuit functions, and indicate how neural circuitry can compensate for global FMRP loss to reinstate normal critical period brain circuit remodeling.SIGNIFICANCE STATEMENT Fragile X syndrome (FXS), the leading monogenic cause of intellectual disability and autism spectrum disorder (ASD), manifests severe neurodevelopmental delays. Likewise, FXS disease models display disrupted neurodevelopmental critical periods. In the well-mapped Drosophila olfactory circuit model, perturbing the causative fragile X mental retardation protein (FMRP) within a single olfactory sensory neuron (OSN) class impairs odorant-dependent remodeling during an early-life critical period. Importantly, this impairment requires activation of other OSNs, and the olfactory circuit can compensate when FMRP is removed from all OSNs. Understanding the neuron-specific FMRP requirements within a developing neural circuit, as well as the FMRP loss compensation mechanisms, should help us engineer FXS treatments. This work suggests FXS treatments could use homeostatic mechanisms to alleviate circuit-level deficits.
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39
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Gamma power abnormalities in a Fmr1-targeted transgenic rat model of fragile X syndrome. Sci Rep 2020; 10:18799. [PMID: 33139785 PMCID: PMC7608556 DOI: 10.1038/s41598-020-75893-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/21/2020] [Indexed: 12/11/2022] Open
Abstract
Fragile X syndrome (FXS) is characteristically displayed intellectual disability, hyperactivity, anxiety, and abnormal sensory processing. Electroencephalography (EEG) abnormalities are also observed in subjects with FXS, with many researchers paying attention to these as biomarkers. Despite intensive preclinical research using Fmr1 knock out (KO) mice, an effective treatment for FXS has yet to be developed. Here, we examined Fmr1-targeted transgenic rats (Fmr1-KO rats) as an alternative preclinical model of FXS. We characterized the EEG phenotypes of Fmr1-KO rats by measuring basal EEG power and auditory steady state response (ASSR) to click trains of stimuli at a frequency of 10–80 Hz. Fmr1-KO rats exhibited reduced basal alpha power and enhanced gamma power, and these rats showed enhanced locomotor activity in novel environment. While ASSR clearly peaked at around 40 Hz, both inter-trial coherence (ITC) and event-related spectral perturbation (ERSP) were significantly reduced at the gamma frequency band in Fmr1-KO rats. Fmr1-KO rats showed gamma power abnormalities and behavioral hyperactivity that were consistent with observations reported in mouse models and subjects with FXS. These results suggest that gamma power abnormalities are a translatable biomarker among species and demonstrate the utility of Fmr1-KO rats for investigating drugs for the treatment of FXS.
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40
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Jin SX, Higashimori H, Schin C, Tamashiro A, Men Y, Chiang MSR, Jarvis R, Cox D, Feig L, Yang Y. Astroglial FMRP modulates synaptic signaling and behavior phenotypes in FXS mouse model. Glia 2020; 69:594-608. [PMID: 32970902 DOI: 10.1002/glia.23915] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 09/09/2020] [Accepted: 09/11/2020] [Indexed: 12/16/2022]
Abstract
Fragile X syndrome (FXS) is one of the most common inherited intellectual disability (ID) disorders, in which the loss of FMRP protein induces a range of cellular signaling changes primarily through excess protein synthesis. Although neuron-centered molecular and cellular events underlying FXS have been characterized, how different CNS cell types are involved in typical FXS synaptic signaling changes and behavioral phenotypes is largely unknown. Recent evidence suggests that selective loss of astroglial FMRP is able to dysregulate glutamate uptake, increase spine density, and impair motor-skill learning. Here we investigated the effect of astroglial FMRP on synaptic signaling and FXS-related behavioral and learning phenotypes in astroglial Fmr1 cKO and cON mice in which FMRP expression is selectively diminished or restored in astroglia. We found that selective loss of astroglial FMRP contributes to cortical hyperexcitability by enhancing NMDAR-mediated evoked but not spontaneous miniEPSCs and elongating cortical UP state duration. Selective loss of astroglial FMRP is also sufficient to increase locomotor hyperactivity, significantly diminish social novelty preference, and induce memory acquisition and extinction deficits in astroglial Fmr1 cKO mice. Importantly, re-expression of astroglial FMRP is able to significantly rescue the hyperactivity (evoked NMDAR response, UP state duration, and open field test) and social novelty preference in astroglial Fmr1 cON mice. These results demonstrate a profound role of astroglial FMRP in the evoked synaptic signaling, spontaneously occurring cortical UP states, and FXS-related behavioral and learning phenotypes and provide important new insights in the cell type consideration for the FMRP reactivation strategy.
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Affiliation(s)
- Shan-Xue Jin
- Department of Developmental, Molecular, and Cellular Biology, Tufts University, Boston, Massachusetts, USA
| | - Haruki Higashimori
- Department of Neuroscience, School of Medicine, Tufts University, Boston, Massachusetts, USA
| | - Christina Schin
- Department of Neuroscience, School of Medicine, Tufts University, Boston, Massachusetts, USA
| | - Alessandra Tamashiro
- Department of Neuroscience, School of Medicine, Tufts University, Boston, Massachusetts, USA
| | - Yuqin Men
- Department of Neuroscience, School of Medicine, Tufts University, Boston, Massachusetts, USA
| | - Ming Sum R Chiang
- Department of Neuroscience, School of Medicine, Tufts University, Boston, Massachusetts, USA
| | - Rachel Jarvis
- Department of Neuroscience, School of Medicine, Tufts University, Boston, Massachusetts, USA
| | - Dan Cox
- Department of Neuroscience, School of Medicine, Tufts University, Boston, Massachusetts, USA
| | - Larry Feig
- Department of Developmental, Molecular, and Cellular Biology, Tufts University, Boston, Massachusetts, USA.,Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, USA
| | - Yongjie Yang
- Department of Neuroscience, School of Medicine, Tufts University, Boston, Massachusetts, USA.,Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, USA
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41
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FMR1 loss in a human stem cell model reveals early changes to intrinsic membrane excitability. Dev Biol 2020; 468:93-100. [PMID: 32976839 DOI: 10.1016/j.ydbio.2020.09.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 09/18/2020] [Indexed: 11/21/2022]
Abstract
Fragile X mental retardation 1 (FMR1) encodes the RNA binding protein FMRP. Loss of FMRP drives Fragile X syndrome (FXS), the leading inherited cause of intellectual disability and a leading monogenic cause of autism. While cortical hyperexcitability is a hallmark of FXS, the reported phenotypes and underlying mechanisms, including alterations in synaptic transmission and ion channel properties, are heterogeneous and at times contradictory. Here, we report the generation of new isogenic FMR1y/+ and FMR1y/- human pluripotent stem cell (hPSC) lines using CRISPR-Cas9 to facilitate the study of how complete FMRP loss, independent of genetic background, drives molecular and cellular alterations relevant for FXS. After differentiating these stem cell tools into excitatory neurons, we systematically assessed the impact of FMRP loss on intrinsic membrane and synaptic properties over time. Using whole-cell patch clamp analyses, we found that FMR1y/- neurons overall showed an increased intrinsic membrane excitability compared to age-matched FMR1y/+ controls, with no discernable alternations in synaptic transmission. Surprisingly, longitudinal analyses of cell intrinsic defects revealed that a majority of significant changes emerged early following in vitro differentiation and some were not stable over time. Collectively, this study provides a new isogenic hPSC model which can be further leveraged by the scientific community to investigate basic mechanisms of FMR1 gene function relevant for FXS. Moreover, our results suggest that precocious changes in the intrinsic membrane properties during early developmental could be a critical cellular pathology ultimately contributing to cortical hyperexcitability in FXS.
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42
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Dong HW, Erickson K, Lee JR, Merritt J, Fu C, Neul JL. Detection of neurophysiological features in female R255X MeCP2 mutation mice. Neurobiol Dis 2020; 145:105083. [PMID: 32927061 PMCID: PMC7572861 DOI: 10.1016/j.nbd.2020.105083] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 08/11/2020] [Accepted: 09/08/2020] [Indexed: 02/07/2023] Open
Abstract
Rett syndrome (RTT) is a severe neurodevelopmental disorder (NDD) that is nearly always caused by loss of function mutations in Methyl-CpG-binding Protein 2 (MECP2) and shares many clinical features with other NDD. Genetic restoration of Mecp2 in symptomatic mice lacking MeCP2 expression can reverse symptoms, providing hope that disease modifying therapies can be identified for RTT. Effective and rapid clinical trial completion relies on well-defined clinical outcome measures and robust biomarkers of treatment responses. Studies on other NDD have found evidence of differences in neurophysiological measures that correlate with disease severity. However, currently there are no well-validated biomarkers in RTT to predict disease prognosis or treatment responses. To address this, we characterized neurophysiological features in a mouse model of RTT containing a knock-in nonsense mutation (p.R255X) in the Mecp2 locus. We found a variety of changes in heterozygous female Mecp2R255X/X mice including age-related changes in sleep/wake architecture, alterations in baseline EEG power, increased incidence of spontaneous epileptiform discharges, and changes in auditory evoked potentials. Furthermore, we identified association of some neurophysiological features with disease severity. These findings provide a set of potential non-invasive and translatable biomarkers that can be utilized in preclinical therapy trials in animal models of RTT and eventually within the context of clinical trials.
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Affiliation(s)
- Hong-Wei Dong
- Department of Pediatrics, Division of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37203, USA.
| | - Kirsty Erickson
- Department of Pediatrics, Division of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37203, USA.
| | - Jessica R Lee
- Department of Pediatrics, Division of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37203, USA.
| | - Jonathan Merritt
- Department of Pediatrics, Division of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37203, USA.
| | - Cary Fu
- Department of Pediatrics, Division of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37203, USA.
| | - Jeffrey L Neul
- Department of Pediatrics, Division of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37203, USA.
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Astrocytic Ephrin-B1 Controls Excitatory-Inhibitory Balance in Developing Hippocampus. J Neurosci 2020; 40:6854-6871. [PMID: 32801156 DOI: 10.1523/jneurosci.0413-20.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 06/08/2020] [Accepted: 07/20/2020] [Indexed: 12/12/2022] Open
Abstract
Astrocytes are implicated in synapse formation and elimination, which are associated with developmental refinements of neuronal circuits. Astrocyte dysfunctions are also linked to synapse pathologies associated with neurodevelopmental disorders and neurodegenerative diseases. Although several astrocyte-derived secreted factors are implicated in synaptogenesis, the role of contact-mediated glial-neuronal interactions in synapse formation and elimination during development is still unknown. In this study, we examined whether the loss or overexpression of the membrane-bound ephrin-B1 in astrocytes during postnatal day (P) 14-28 period would affect synapse formation and maturation in the developing hippocampus. We found enhanced excitation of CA1 pyramidal neurons in astrocyte-specific ephrin-B1 KO male mice, which coincided with a greater vGlut1/PSD95 colocalization, higher dendritic spine density, and enhanced evoked AMPAR and NMDAR EPSCs. In contrast, EPSCs were reduced in CA1 neurons neighboring ephrin-B1-overexpressing astrocytes. Overexpression of ephrin-B1 in astrocytes during P14-28 developmental period also facilitated evoked IPSCs in CA1 neurons, while evoked IPSCs and miniature IPSC amplitude were reduced following astrocytic ephrin-B1 loss. Lower numbers of parvalbumin-expressing cells and a reduction in the inhibitory VGAT/gephyrin-positive synaptic sites on CA1 neurons in the stratum pyramidale and stratum oriens layers of KO hippocampus may contribute to reduced inhibition and higher excitation. Finally, dysregulation of excitatory/inhibitory balance in KO male mice is most likely responsible for impaired sociability observed in these mice. The ability of astrocytic ephrin-B1 to influence both excitatory and inhibitory synapses during development can potentially contribute to developmental refinement of neuronal circuits.SIGNIFICANCE STATEMENT This report establishes a link between astrocytes and the development of excitatory and inhibitory balance in the mouse hippocampus during early postnatal development. We provide new evidence that astrocytic ephrin-B1 differentially regulates development of excitatory and inhibitory circuits in the hippocampus during early postnatal development using a multidisciplinary approach. The ability of astrocytic ephrin-B1 to influence both excitatory and inhibitory synapses during development can potentially contribute to developmental refinement of neuronal circuits and associated behaviors. Given widespread and growing interest in the astrocyte-mediated mechanisms that regulate synapse development, and the role of EphB receptors in neurodevelopmental disorders, these findings establish a foundation for future studies of astrocytes in clinically relevant conditions.
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Lovelace JW, Ethell IM, Binder DK, Razak KA. Minocycline Treatment Reverses Sound Evoked EEG Abnormalities in a Mouse Model of Fragile X Syndrome. Front Neurosci 2020; 14:771. [PMID: 32848552 PMCID: PMC7417521 DOI: 10.3389/fnins.2020.00771] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 06/30/2020] [Indexed: 01/19/2023] Open
Abstract
Fragile X Syndrome (FXS) is a leading known genetic cause of intellectual disability. Many symptoms of FXS overlap with those in autism including repetitive behaviors, language delays, anxiety, social impairments and sensory processing deficits. Electroencephalogram (EEG) recordings from humans with FXS and an animal model, the Fmr1 knockout (KO) mouse, show remarkably similar phenotypes suggesting that EEG phenotypes can serve as biomarkers for developing treatments. This includes enhanced resting gamma band power and sound evoked total power, and reduced fidelity of temporal processing and habituation of responses to repeated sounds. Given the therapeutic potential of the antibiotic minocycline in humans with FXS and animal models, it is important to determine sensitivity and selectivity of EEG responses to minocycline. Therefore, in this study, we examined if a 10-day treatment of adult Fmr1 KO mice with minocycline (oral gavage, 30 mg/kg per day) would reduce EEG abnormalities. We tested if minocycline treatment has specific effects based on the EEG measurement type (e.g., resting versus sound-evoked) from the frontal and auditory cortex of the Fmr1 KO mice. We show increased resting EEG gamma power and reduced phase locking to time varying stimuli as well as the 40 Hz auditory steady state response in the Fmr1 KO mice in the pre-drug condition. Minocycline treatment increased gamma band phase locking in response to auditory stimuli, and reduced sound-evoked power of auditory event related potentials (ERP) in Fmr1 KO mice compared to vehicle treatment. Minocycline reduced resting EEG gamma power in Fmr1 KO mice, but this effect was similar to vehicle treatment. We also report frequency band-specific effects on EEG responses. Taken together, these data indicate that sound-evoked EEG responses may serve as more sensitive measures, compared to resting EEG measures, to isolate minocycline effects from placebo in humans with FXS. Given the use of minocycline and EEG recordings in a number of neurodegenerative and neurodevelopmental conditions, these findings may be more broadly applicable in translational neuroscience.
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Affiliation(s)
- Jonathan W Lovelace
- Department of Psychology and Neuroscience Graduate Program, University of California, Riverside, Riverside, CA, United States
| | - Iryna M Ethell
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA, United States.,Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, United States
| | - Devin K Binder
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA, United States.,Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, United States
| | - Khaleel A Razak
- Department of Psychology and Neuroscience Graduate Program, University of California, Riverside, Riverside, CA, United States.,Neuroscience Graduate Program, University of California, Riverside, Riverside, CA, United States
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Sanz-Morello B, Pfisterer U, Winther Hansen N, Demharter S, Thakur A, Fujii K, Levitskii SA, Montalant A, Korshunova I, Mammen PP, Kamenski P, Noguchi S, Aldana BI, Hougaard KS, Perrier JF, Khodosevich K. Complex IV subunit isoform COX6A2 protects fast-spiking interneurons from oxidative stress and supports their function. EMBO J 2020; 39:e105759. [PMID: 32744742 DOI: 10.15252/embj.2020105759] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 01/01/2023] Open
Abstract
Parvalbumin-positive (PV+ ) fast-spiking interneurons are essential to control the firing activity of principal neuron ensembles, thereby regulating cognitive processes. The high firing frequency activity of PV+ interneurons imposes high-energy demands on their metabolism that must be supplied by distinctive machinery for energy generation. Exploring single-cell transcriptomic data for the mouse cortex, we identified a metabolism-associated gene with highly restricted expression to PV+ interneurons: Cox6a2, which codes for an isoform of a cytochrome c oxidase subunit. Cox6a2 deletion in mice disrupts perineuronal nets and enhances oxidative stress in PV+ interneurons, which in turn impairs the maturation of their morphological and functional properties. Such dramatic effects were likely due to an essential role of COX6A2 in energy balance of PV+ interneurons, underscored by a decrease in the ATP-to-ADP ratio in Cox6a2-/- PV+ interneurons. Energy disbalance and aberrant maturation likely hinder the integration of PV+ interneurons into cortical neuronal circuits, leading to behavioral alterations in mice. Additionally, in a human patient bearing mutations in COX6A2, we found a potential association of the mutations with mental/neurological abnormalities.
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Affiliation(s)
- Berta Sanz-Morello
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ulrich Pfisterer
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Samuel Demharter
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ashish Thakur
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Katsunori Fujii
- Department of Pediatrics, Chiba University Graduate School of Medicine, Chiba, Japan
| | | | - Alexia Montalant
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Irina Korshunova
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Pradeep Pa Mammen
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Piotr Kamenski
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Satoru Noguchi
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.,Medical Genome Center, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Blanca Irene Aldana
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Karin Sørig Hougaard
- Section of Environmental Health, National Research Centre for the Working Environment, Copenhagen, Denmark.,Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | | | - Konstantin Khodosevich
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Pirbhoy PS, Rais M, Lovelace JW, Woodard W, Razak KA, Binder DK, Ethell IM. Acute pharmacological inhibition of matrix metalloproteinase-9 activity during development restores perineuronal net formation and normalizes auditory processing in Fmr1 KO mice. J Neurochem 2020; 155:538-558. [PMID: 32374912 DOI: 10.1111/jnc.15037] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/31/2020] [Accepted: 04/30/2020] [Indexed: 12/13/2022]
Abstract
Individuals with Fragile X Syndrome (FXS) and autism spectrum disorder (ASD) exhibit cognitive impairments, social deficits, increased anxiety, and sensory hyperexcitability. Previously, we showed that elevated levels of matrix metalloproteinase-9 (MMP-9) may contribute to abnormal development of parvalbumin (PV) interneurons and perineuronal nets (PNNs) in the developing auditory cortex (AC) of Fmr1 knock-out (KO) mice, which likely underlie auditory hypersensitivity. Thus, MMP-9 may serve as a potential target for treatment of auditory hypersensitivity in FXS. Here, we used the MMP-2/9 inhibitor, SB-3CT, to pharmacologically inhibit MMP-9 activity during a specific developmental period and to test whether inhibition of MMP-9 activity reverses neural oscillation deficits and behavioral impairments by enhancing PNN formation around PV cells in Fmr1 KO mice. Electroencephalography (EEG) was used to measure resting state and sound-evoked electrocortical activity in auditory and frontal cortices of postnatal day (P)22-23 male mice before and one-day after treatment with SB-3CT (25 mg/kg) or vehicle. At P27-28, animal behaviors were tested to measure the effects of the treatment on anxiety and hyperactivity. Results show that acute inhibition of MMP-9 activity improved evoked synchronization to auditory stimuli and ameliorated mouse behavioral deficits. MMP-9 inhibition enhanced PNN formation, increased PV levels and TrkB phosphorylation yet reduced Akt phosphorylation in the AC of Fmr1 KO mice. Our results show that MMP-9 inhibition during early postnatal development is beneficial in reducing some auditory processing deficits in the FXS mouse model and may serve as a candidate therapeutic for reversing sensory hypersensitivity in FXS and possibly other ASDs.
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Affiliation(s)
- Patricia S Pirbhoy
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Maham Rais
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Jonathan W Lovelace
- Department of Psychology, University of California Riverside, Riverside, CA, USA
| | - Walker Woodard
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Khaleel A Razak
- Department of Psychology, University of California Riverside, Riverside, CA, USA
| | - Devin K Binder
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Iryna M Ethell
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
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Nguyen AO, Binder DK, Ethell IM, Razak KA. Abnormal development of auditory responses in the inferior colliculus of a mouse model of Fragile X Syndrome. J Neurophysiol 2020; 123:2101-2121. [PMID: 32319849 DOI: 10.1152/jn.00706.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Sensory processing abnormalities are frequently associated with autism spectrum disorders, but the underlying mechanisms are unclear. Here we studied auditory processing in a mouse model of Fragile X Syndrome (FXS), a leading known genetic cause of autism and intellectual disability. Both humans with FXS and the Fragile X mental retardation gene (Fmr1) knockout (KO) mouse model show auditory hypersensitivity, with the latter showing a strong propensity for audiogenic seizures (AGS) early in development. Because midbrain abnormalities cause AGS, we investigated whether the inferior colliculus (IC) of the Fmr1 KO mice shows abnormal auditory processing compared with wild-type (WT) controls at specific developmental time points. Using antibodies against neural activity marker c-Fos, we found increased density of c-Fos+ neurons in the IC, but not auditory cortex, of Fmr1 KO mice at P21 and P34 following sound presentation. In vivo single-unit recordings showed that IC neurons of Fmr1 KO mice are hyperresponsive to tone bursts and amplitude-modulated tones during development and show broader frequency tuning curves. There were no differences in rate-level responses or phase locking to amplitude-modulated tones in IC neurons between genotypes. Taken together, these data provide evidence for the development of auditory hyperresponsiveness in the IC of Fmr1 KO mice. Although most human and mouse work in autism and sensory processing has centered on the forebrain, our new findings, along with recent work on the lower brainstem, suggest that abnormal subcortical responses may underlie auditory hypersensitivity in autism spectrum disorders.NEW & NOTEWORTHY Autism spectrum disorders (ASD) are commonly associated with sensory sensitivity issues, but the underlying mechanisms are unclear. This study presents novel evidence for neural correlates of auditory hypersensitivity in the developing inferior colliculus (IC) in Fmr1 knockout (KO) mouse, a mouse model of Fragile X Syndrome (FXS), a leading genetic cause of ASD. Responses begin to show genotype differences between postnatal days 14 and 21, suggesting an early developmental treatment window.
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Affiliation(s)
- Anna O Nguyen
- Bioengineering Program, University of California, Riverside, California
| | - Devin K Binder
- Graduate Neuroscience Program, University of California, Riverside, California.,Division of Biomedical Sciences, University of California, Riverside, California
| | - Iryna M Ethell
- Graduate Neuroscience Program, University of California, Riverside, California.,Division of Biomedical Sciences, University of California, Riverside, California
| | - Khaleel A Razak
- Graduate Neuroscience Program, University of California, Riverside, California.,Psychology Department, University of California, Riverside, California
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McCullagh EA, Rotschafer SE, Auerbach BD, Klug A, Kaczmarek LK, Cramer KS, Kulesza RJ, Razak KA, Lovelace JW, Lu Y, Koch U, Wang Y. Mechanisms underlying auditory processing deficits in Fragile X syndrome. FASEB J 2020; 34:3501-3518. [PMID: 32039504 DOI: 10.1096/fj.201902435r] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 12/31/2019] [Accepted: 01/18/2020] [Indexed: 01/14/2023]
Abstract
Autism spectrum disorders (ASD) are strongly associated with auditory hypersensitivity or hyperacusis (difficulty tolerating sounds). Fragile X syndrome (FXS), the most common monogenetic cause of ASD, has emerged as a powerful gateway for exploring underlying mechanisms of hyperacusis and auditory dysfunction in ASD. This review discusses examples of disruption of the auditory pathways in FXS at molecular, synaptic, and circuit levels in animal models as well as in FXS individuals. These examples highlight the involvement of multiple mechanisms, from aberrant synaptic development and ion channel deregulation of auditory brainstem circuits, to impaired neuronal plasticity and network hyperexcitability in the auditory cortex. Though a relatively new area of research, recent discoveries have increased interest in auditory dysfunction and mechanisms underlying hyperacusis in this disorder. This rapidly growing body of data has yielded novel research directions addressing critical questions regarding the timing and possible outcomes of human therapies for auditory dysfunction in ASD.
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Affiliation(s)
- Elizabeth A McCullagh
- Department of Physiology and Biophysics, University of Colorado Anschutz, Aurora, CO, USA.,Department of Integrative Biology, Oklahoma State University, Stillwater, OK, USA
| | - Sarah E Rotschafer
- Department of Neurobiology and Behavior, University of California, Irvine, CA, USA.,Department of Biomedical Sciences, Mercer University School of Medicine, Savannah, GA, USA
| | - Benjamin D Auerbach
- Center for Hearing and Deafness, Department of Communicative Disorders & Sciences, SUNY at Buffalo, Buffalo, NY, USA
| | - Achim Klug
- Department of Physiology and Biophysics, University of Colorado Anschutz, Aurora, CO, USA
| | - Leonard K Kaczmarek
- Departments of Pharmacology and Cellular and Molecular Physiology, Yale University, New Haven, CT, USA
| | - Karina S Cramer
- Department of Neurobiology and Behavior, University of California, Irvine, CA, USA
| | - Randy J Kulesza
- Department of Anatomy, Lake Erie College of Osteopathic Medicine, Erie, PA, USA
| | - Khaleel A Razak
- Department of Psychology, University of California, Riverside, CA, USA
| | | | - Yong Lu
- Department of Anatomy and Neurobiology, College of Medicine, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Ursula Koch
- Institute of Biology, Neurophysiology, Freie Universität Berlin, Berlin, Germany
| | - Yuan Wang
- Department of Biomedical Sciences, Program in Neuroscience, Florida State University, Tallahassee, FL, USA
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Jonak CR, Lovelace JW, Ethell IM, Razak KA, Binder DK. Multielectrode array analysis of EEG biomarkers in a mouse model of Fragile X Syndrome. Neurobiol Dis 2020; 138:104794. [PMID: 32036032 DOI: 10.1016/j.nbd.2020.104794] [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: 11/04/2019] [Revised: 01/27/2020] [Accepted: 02/05/2020] [Indexed: 02/06/2023] Open
Abstract
Fragile X Syndrome (FXS) is a leading known genetic cause of intellectual disability with symptoms that include increased anxiety and social and sensory processing deficits. Recent EEG studies in humans with FXS have identified neural oscillation deficits that include increased resting state gamma power, increased amplitude of auditory evoked potentials, and reduced inter-trial phase coherence of sound-evoked gamma oscillations. Identification of comparable EEG biomarkers in mouse models of FXS could facilitate the pre-clinical to clinical therapeutic pipeline. However, while human EEG studies have involved 128-channel scalp EEG acquisition, no mouse studies have been performed with more than three EEG channels. In the current study, we employed a recently developed 30-channel mouse multielectrode array (MEA) system to record and analyze resting and stimulus-evoked EEG signals in WT vs. Fmr1 KO mice. Using this system, we now report robust MEA-derived phenotypes including higher resting EEG power, altered event-related potentials (ERPs) and reduced inter-trial phase coherence to auditory chirp stimuli in Fmr1 KO mice that are remarkably similar to those reported in humans with FXS. We propose that the MEA system can be used for: (i) derivation of higher-level EEG parameters; (ii) EEG biomarkers for drug testing; and (ii) mechanistic studies of FXS pathophysiology.
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Affiliation(s)
- Carrie R Jonak
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, United States of America
| | - Jonathan W Lovelace
- Department of Psychology, University of California, Riverside, United States of America
| | - Iryna M Ethell
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, United States of America; Neuroscience Graduate Program, University of California, Riverside, United States of America
| | - Khaleel A Razak
- Neuroscience Graduate Program, University of California, Riverside, United States of America; Department of Psychology, University of California, Riverside, United States of America
| | - Devin K Binder
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, United States of America; Neuroscience Graduate Program, University of California, Riverside, United States of America.
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