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Pedapati EV, Ethridge LE, Liu Y, Liu R, Sweeney JA, DeStefano LA, Miyakoshi M, Razak K, Schmitt LM, Moore DR, Gilbert DL, Wu SW, Smith E, Shaffer RC, Dominick KC, Horn PS, Binder D, Erickson CA. Frontal Cortex Hyperactivation and Gamma Desynchrony in Fragile X Syndrome: Correlates of Auditory Hypersensitivity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.13.598957. [PMID: 38915683 PMCID: PMC11195233 DOI: 10.1101/2024.06.13.598957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Fragile X syndrome (FXS) is an X-linked disorder that often leads to intellectual disability, anxiety, and sensory hypersensitivity. While sound sensitivity (hyperacusis) is a distressing symptom in FXS, its neural basis is not well understood. It is postulated that hyperacusis may stem from temporal lobe hyperexcitability or dysregulation in top-down modulation. Studying the neural mechanisms underlying sound sensitivity in FXS using scalp electroencephalography (EEG) is challenging because the temporal and frontal regions have overlapping neural projections that are difficult to differentiate. To overcome this challenge, we conducted EEG source analysis on a group of 36 individuals with FXS and 39 matched healthy controls. Our goal was to characterize the spatial and temporal properties of the response to an auditory chirp stimulus. Our results showed that males with FXS exhibit excessive activation in the frontal cortex in response to the stimulus onset, which may reflect changes in top-down modulation of auditory processing. Additionally, during the chirp stimulus, individuals with FXS demonstrated a reduction in typical gamma phase synchrony, along with an increase in asynchronous gamma power, across multiple regions, most strongly in temporal cortex. Consistent with these findings, we observed a decrease in the signal-to-noise ratio, estimated by the ratio of synchronous to asynchronous gamma activity, in individuals with FXS. Furthermore, this ratio was highly correlated with performance in an auditory attention task. Compared to controls, males with FXS demonstrated elevated bidirectional frontotemporal information flow at chirp onset. The evidence indicates that both temporal lobe hyperexcitability and disruptions in top-down regulation play a role in auditory sensitivity disturbances in FXS. These findings have the potential to guide the development of therapeutic targets and back-translation strategies.
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Affiliation(s)
- Ernest V Pedapati
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Department of Psychiatry, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Lauren E Ethridge
- Department of Pediatrics, Section on Developmental and Behavioral Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Department of Psychology, University of Oklahoma, Norman, OK, United States
| | - Yanchen Liu
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Rui Liu
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - John A Sweeney
- Department of Psychiatry, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Lisa A DeStefano
- Division of Developmental and Behavioral Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Makoto Miyakoshi
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Khaleel Razak
- Department of Psychology, University of California, Riverside, Riverside, CA, United States
| | - Lauren M Schmitt
- Division of Developmental and Behavioral Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - David R Moore
- Communication Sciences Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Manchester Centre for Audiology and Deafness, University of Manchester, Manchester, UK
| | - Donald L Gilbert
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Steve W Wu
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Elizabeth Smith
- Division of Developmental and Behavioral Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Rebecca C Shaffer
- Division of Developmental and Behavioral Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Kelli C Dominick
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Department of Psychiatry, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Paul S Horn
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Devin Binder
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, United States
| | - Craig A Erickson
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Department of Psychiatry, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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Zhan X, Asmara H, Pfaffinger P, Turner RW. Calcium-Dependent Regulation of Neuronal Excitability Is Rescued in Fragile X Syndrome by a Tat-Conjugated N-Terminal Fragment of FMRP. J Neurosci 2024; 44:e0136242024. [PMID: 38664011 PMCID: PMC11112635 DOI: 10.1523/jneurosci.0136-24.2024] [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: 01/18/2024] [Revised: 04/04/2024] [Accepted: 04/12/2024] [Indexed: 05/24/2024] Open
Abstract
Fragile X syndrome (FXS) arises from the loss of fragile X messenger ribonucleoprotein (FMRP) needed for normal neuronal excitability and circuit functions. Recent work revealed that FMRP contributes to mossy fiber long-term potentiation by adjusting the Kv4 A-type current availability through interactions with a Cav3-Kv4 ion channel complex, yet the mechanism has not yet been defined. In this study using wild-type and Fmr1 knock-out (KO) tsA-201 cells and cerebellar sections from male Fmr1 KO mice, we show that FMRP associates with all subunits of the Cav3.1-Kv4.3-KChIP3 complex and is critical to enabling calcium-dependent shifts in Kv4.3 inactivation to modulate the A-type current. Specifically, upon depolarization Cav3 calcium influx activates dual-specific phosphatase 1/6 (DUSP1/6) to deactivate ERK1/2 (ERK) and lower phosphorylation of Kv4.3, a signaling pathway that does not function in Fmr1 KO cells. In Fmr1 KO mouse tissue slices, cerebellar granule cells exhibit a hyperexcitable response to membrane depolarizations. Either incubating Fmr1 KO cells or in vivo administration of a tat-conjugated FMRP N-terminus fragment (FMRP-N-tat) rescued Cav3-Kv4 function and granule cell excitability, with a decrease in the level of DUSP6. Together these data reveal a Cav3-activated DUSP signaling pathway critical to the function of a FMRP-Cav3-Kv4 complex that is misregulated in Fmr1 KO conditions. Moreover, FMRP-N-tat restores function of this complex to rescue calcium-dependent control of neuronal excitability as a potential therapeutic approach to alleviating the symptoms of FXS.
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Affiliation(s)
- Xiaoqin Zhan
- Hotchkiss Brain Institute, Baylor College of Medicine, Houston, Texas 77030
- Alberta Children's Hospital Research Institute, Baylor College of Medicine, Houston, Texas 77030
| | - Hadhimulya Asmara
- Hotchkiss Brain Institute, Baylor College of Medicine, Houston, Texas 77030
- Alberta Children's Hospital Research Institute, Baylor College of Medicine, Houston, Texas 77030
| | - Paul Pfaffinger
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Ray W Turner
- Hotchkiss Brain Institute, Baylor College of Medicine, Houston, Texas 77030
- Alberta Children's Hospital Research Institute, Baylor College of Medicine, Houston, Texas 77030
- Department Clinical Neurosciences, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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3
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Ntoulas G, Brakatselos C, Nakas G, Asprogerakas MZ, Delis F, Leontiadis LJ, Trompoukis G, Papatheodoropoulos C, Gkikas D, Valakos D, Vatsellas G, Politis PK, Polissidis A, Antoniou K. Multi-level profiling of the Fmr1 KO rat unveils altered behavioral traits along with aberrant glutamatergic function. Transl Psychiatry 2024; 14:104. [PMID: 38378836 PMCID: PMC10879511 DOI: 10.1038/s41398-024-02815-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 01/19/2024] [Accepted: 02/01/2024] [Indexed: 02/22/2024] Open
Abstract
Fragile X syndrome (FXS) is the most common cause of inherited intellectual disabilities and the most prevalent monogenic cause of autism. Although the knockout (KO) of the Fmr1 gene homolog in mice is primarily used for elucidating the neurobiological substrate of FXS, there is limited association of the experimental data with the pathophysiological condition in humans. The use of Fmr1 KO rats offers additional translational validity in this regard. Therefore, we employed a multi-level approach to study the behavioral profile and the glutamatergic and GABAergic neurotransmission status in pathophysiology-associated brain structures of Fmr1 KO rats, including the recordings of evoked and spontaneous field potentials from hippocampal slices, paralleled with next-generation RNA sequencing (RNA-seq). We found that these rats exhibit hyperactivity and cognitive deficits, along with characteristic bidirectional glutamatergic and GABAergic alterations in the prefrontal cortex and the hippocampus. These results are coupled to affected excitability and local inhibitory processes in the hippocampus, along with a specific transcriptional profile, highlighting dysregulated hippocampal network activity in KO rats. Overall, our data provide novel insights concerning the biobehavioral profile of FmR1 KO rats and translationally upscales our understanding on pathophysiology and symptomatology of FXS syndrome.
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Affiliation(s)
- George Ntoulas
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences University of Ioannina, Ioannina, Greece
| | - Charalampos Brakatselos
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences University of Ioannina, Ioannina, Greece
| | - Gerasimos Nakas
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences University of Ioannina, Ioannina, Greece
| | - Michail-Zois Asprogerakas
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences University of Ioannina, Ioannina, Greece
| | - Foteini Delis
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences University of Ioannina, Ioannina, Greece
| | - Leonidas J Leontiadis
- Laboratory of Neurophysiology, Department of Medicine, University of Patras, Rion, Greece
| | - George Trompoukis
- Laboratory of Neurophysiology, Department of Medicine, University of Patras, Rion, Greece
| | | | - Dimitrios Gkikas
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Dimitrios Valakos
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Giannis Vatsellas
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Panagiotis K Politis
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Alexia Polissidis
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences University of Ioannina, Ioannina, Greece
- Center of Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Katerina Antoniou
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences University of Ioannina, Ioannina, Greece.
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Viragh E, Asztalos L, Fenckova M, Szlanka T, Gyorgypal Z, Kovacs K, IntHout J, Cizek P, Konda M, Szucs E, Zvara A, Biro J, Csapo E, Lukacsovich T, Hegedus Z, Puskas L, Schenck A, Asztalos Z. Pre-Pulse Inhibition of an escape response in adult fruit fly, Drosophila melanogaster. RESEARCH SQUARE 2024:rs.3.rs-3853873. [PMID: 38343805 PMCID: PMC10854311 DOI: 10.21203/rs.3.rs-3853873/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/19/2024]
Abstract
Pre-Pulse Inhibition (PPI) is a neural process where suppression of a startle response is elicited by preceding the startling stimulus (Pulse) with a weak, non-startling one (Pre-Pulse). Defective PPI is widely employed as a behavioural endophenotype in humans and mammalian disorder-relevant models for neuropsychiatric disorders. We have developed a user-friendly, semi-automated, high-throughput-compatible Drosophila light-off jump response PPI paradigm, with which we demonstrate that PPI, with similar parameters measured in mammals, exists in adults of this model organism. We report that Drosophila PPI is affected by reduced expression of Dysbindin and both reduced and increased expression of Nmdar1 (N-methyl-D-aspartate receptor 1), perturbations associated with schizophrenia. Studying the biology of PPI in an organism that offers a plethora of genetic tools and a complex and well characterized connectome will greatly facilitate our efforts to gain deeper insight into the aetiology of human mental disorders, while reducing the need for mammalian models.
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Affiliation(s)
- Erika Viragh
- Institute of Biochemistry, HUN-REN Biological Research Centre, Szeged, Hungary
- Aktogen Hungary Ltd., Szeged, Hungary
| | - Lenke Asztalos
- Aktogen Hungary Ltd., Szeged, Hungary
- Aktogen Ltd., Department of Genetics, University of Cambridge, Cambridge, United Kingdom; Current address: Aktogen Ltd. Ramsey, Huntingdon, United Kingdom
| | - Michaela Fenckova
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
- Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia in Ceske Budejovice, Ceske Budejovice, Czechia
| | - Tamas Szlanka
- Institute of Biochemistry, HUN-REN Biological Research Centre, Szeged, Hungary
- Aktogen Hungary Ltd., Szeged, Hungary
| | - Zoltan Gyorgypal
- Institute of Biophysics & Core Facilities, HUN-REN Biological Research Centre, Szeged, Hungary
| | - Karoly Kovacs
- Institute of Biochemistry, HUN-REN Biological Research Centre, Szeged, Hungary
- HCEMM-BRC Metabolic Systems Biology Lab, Szeged, Hungary
| | - Joanna IntHout
- Department for Health Evidence (HEV), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Pavel Cizek
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Mihaly Konda
- Aktogen Hungary Ltd., Szeged, Hungary
- Voalaz Ltd., Szeged, Hungary
| | | | - Agnes Zvara
- Laboratory of Functional Genomics, HUN-REN Biological Research Centre Szeged, Hungary
| | | | | | | | - Zoltan Hegedus
- Institute of Biophysics & Core Facilities, HUN-REN Biological Research Centre, Szeged, Hungary
| | - Laszlo Puskas
- Laboratory of Functional Genomics, HUN-REN Biological Research Centre Szeged, Hungary
| | - Annette Schenck
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Zoltan Asztalos
- Institute of Biochemistry, HUN-REN Biological Research Centre, Szeged, Hungary
- Aktogen Hungary Ltd., Szeged, Hungary
- Aktogen Ltd., Department of Genetics, University of Cambridge, Cambridge, United Kingdom; Current address: Aktogen Ltd. Ramsey, Huntingdon, United Kingdom
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5
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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 PMCID: PMC11247136 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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Talvio K, Castrén ML. Astrocytes in fragile X syndrome. Front Cell Neurosci 2024; 17:1322541. [PMID: 38259499 PMCID: PMC10800791 DOI: 10.3389/fncel.2023.1322541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 12/11/2023] [Indexed: 01/24/2024] Open
Abstract
Astrocytes have an important role in neuronal maturation and synapse function in the brain. The interplay between astrocytes and neurons is found to be altered in many neurodevelopmental disorders, including fragile X syndrome (FXS) that is the most common inherited cause of intellectual disability and autism spectrum disorder. Transcriptional, functional, and metabolic alterations in Fmr1 knockout mouse astrocytes, human FXS stem cell-derived astrocytes as well as in in vivo models suggest autonomous effects of astrocytes in the neurobiology of FXS. Abnormalities associated with FXS astrocytes include differentiation of central nervous system cell populations, maturation and regulation of synapses, and synaptic glutamate balance. Recently, FXS-specific changes were found more widely in astrocyte functioning, such as regulation of inflammatory pathways and maintenance of lipid homeostasis. Changes of FXS astrocytes impact the brain homeostasis and function both during development and in the adult brain and offer opportunities for novel types of approaches for intervention.
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Affiliation(s)
| | - Maija L. Castrén
- Department of Physiology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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Leontiadis LJ, Trompoukis G, Tsotsokou G, Miliou A, Felemegkas P, Papatheodoropoulos C. Rescue of sharp wave-ripples and prevention of network hyperexcitability in the ventral but not the dorsal hippocampus of a rat model of fragile X syndrome. Front Cell Neurosci 2023; 17:1296235. [PMID: 38107412 PMCID: PMC10722241 DOI: 10.3389/fncel.2023.1296235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 11/06/2023] [Indexed: 12/19/2023] Open
Abstract
Fragile X syndrome (FXS) is a genetic neurodevelopmental disorder characterized by intellectual disability and is related to autism. FXS is caused by mutations of the fragile X messenger ribonucleoprotein 1 gene (Fmr1) and is associated with alterations in neuronal network excitability in several brain areas including hippocampus. The loss of fragile X protein affects brain oscillations, however, the effects of FXS on hippocampal sharp wave-ripples (SWRs), an endogenous hippocampal pattern contributing to memory consolidation have not been sufficiently clarified. In addition, it is still not known whether dorsal and ventral hippocampus are similarly affected by FXS. We used a Fmr1 knock-out (KO) rat model of FXS and electrophysiological recordings from the CA1 area of adult rat hippocampal slices to assess spontaneous and evoked neural activity. We find that SWRs and associated multiunit activity are affected in the dorsal but not the ventral KO hippocampus, while complex spike bursts remain normal in both segments of the KO hippocampus. Local network excitability increases in the dorsal KO hippocampus. Furthermore, specifically in the ventral hippocampus of KO rats we found an increased effectiveness of inhibition in suppressing excitation and an upregulation of α1GABAA receptor subtype. These changes in the ventral KO hippocampus are accompanied by a striking reduction in its susceptibility to induced epileptiform activity. We propose that the neuronal network specifically in the ventral segment of the hippocampus is reorganized in adult Fmr1-KO rats by means of balanced changes between excitability and inhibition to ensure normal generation of SWRs and preventing at the same time derailment of the neural activity toward hyperexcitability.
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8
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Leontiadis LJ, Trompoukis G, Felemegkas P, Tsotsokou G, Miliou A, Papatheodoropoulos C. Increased Inhibition May Contribute to Maintaining Normal Network Function in the Ventral Hippocampus of a Fmr1-Targeted Transgenic Rat Model of Fragile X Syndrome. Brain Sci 2023; 13:1598. [PMID: 38002556 PMCID: PMC10669536 DOI: 10.3390/brainsci13111598] [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: 09/15/2023] [Revised: 11/10/2023] [Accepted: 11/13/2023] [Indexed: 11/26/2023] Open
Abstract
A common neurobiological mechanism in several neurodevelopmental disorders, including fragile X syndrome (FXS), is alterations in the balance between excitation and inhibition in the brain. It is thought that in the hippocampus, as in other brain regions, FXS is associated with increased excitability and reduced inhibition. However, it is still not known whether these changes apply to both the dorsal and ventral hippocampus, which appear to be differently involved in neurodegenerative disorders. Using a Fmr1 knock-out (KO) rat model of FXS, we found increased neuronal excitability in both the dorsal and ventral KO hippocampus and increased excitatory synaptic transmission in the dorsal hippocampus. Interestingly, synaptic inhibition is significantly increased in the ventral but not the dorsal KO hippocampus. Furthermore, the ventral KO hippocampus displays increased expression of the α1GABAA receptor subtype and a remarkably reduced rate of epileptiform discharges induced by magnesium-free medium. In contrast, the dorsal KO hippocampus displays an increased rate of epileptiform discharges and similar expression of α1GABAA receptors compared with the dorsal WT hippocampus. Blockade of α5GABAA receptors by L-655,708 did not affect epileptiform discharges in any genotype or hippocampal segment, and the expression of α5GABAA receptors did not differ between WT and KO hippocampus. These results suggest that the increased excitability of the dorsal KO hippocampus contributes to its heightened tendency to epileptiform discharges, while the increased phasic inhibition in the Fmr1-KO ventral hippocampus may represent a homeostatic mechanism that compensates for the increased excitability reducing its vulnerability to epileptic activity.
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Affiliation(s)
| | | | | | | | | | - Costas Papatheodoropoulos
- Laboratory of Neurophysiology, Department of Medicine, University of Patras, 26504 Rion, Greece; (L.J.L.); (G.T. (George Trompoukis)); (P.F.); (G.T. (Giota Tsotsokou)); (A.M.)
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9
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Chojnacka M, Beroun A, Magnowska M, Stawikowska A, Cysewski D, Milek J, Dziembowska M, Kuzniewska B. Impaired synaptic incorporation of AMPA receptors in a mouse model of fragile X syndrome. Front Mol Neurosci 2023; 16:1258615. [PMID: 38025260 PMCID: PMC10665894 DOI: 10.3389/fnmol.2023.1258615] [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: 07/14/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Fragile X syndrome (FXS) is the most common monogenetic cause of inherited intellectual disability and autism in humans. One of the well-characterized molecular phenotypes of Fmr1 KO mice, a model of FXS, is increased translation of synaptic proteins. Although this upregulation stabilizes in adulthood, abnormalities during the critical period of plasticity have long-term effects on circuit formation and synaptic properties. Using high-resolution quantitative proteomics of synaptoneurosomes isolated from the adult, developed brains of Fmr1 KO mice, we show a differential abundance of proteins regulating the postsynaptic receptor activity of glutamatergic synapses. We investigated the AMPA receptor composition and shuttling in adult Fmr1 KO and WT mice using a variety of complementary experimental strategies such as surface protein crosslinking, immunostaining of surface receptors, and electrophysiology. We discovered that the activity-dependent synaptic delivery of AMPARs is impaired in adult Fmr1 KO mice. Furthermore, we show that Fmr1 KO synaptic AMPARs contain more GluA2 subunits that can be interpreted as a switch in the synaptic AMPAR subtype toward an increased number of Ca2+-impermeable receptors in adult Fmr1 KO synapses.
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Affiliation(s)
- Magdalena Chojnacka
- Laboratory of Molecular Basis of Synaptic Plasticity, Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Anna Beroun
- Laboratory of Neuronal Plasticity, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Marta Magnowska
- Laboratory of Molecular Basis of Synaptic Plasticity, Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Aleksandra Stawikowska
- Laboratory of Molecular Basis of Synaptic Plasticity, Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Dominik Cysewski
- Clinical Research Centre, Medical University of Bialystok, Bialystok, Poland
| | - Jacek Milek
- Laboratory of Molecular Basis of Synaptic Plasticity, Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Magdalena Dziembowska
- Laboratory of Molecular Basis of Synaptic Plasticity, Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Bozena Kuzniewska
- Laboratory of Molecular Basis of Synaptic Plasticity, Centre of New Technologies, University of Warsaw, Warsaw, Poland
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10
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Eberwein AE, Kulkarni SS, Rushton E, Broadie K. Glycosphingolipids are linked to elevated neurotransmission and neurodegeneration in a Drosophila model of Niemann Pick type C. Dis Model Mech 2023; 16:dmm050206. [PMID: 37815467 PMCID: PMC10581387 DOI: 10.1242/dmm.050206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 09/27/2023] [Indexed: 10/11/2023] Open
Abstract
The lipid storage disease Niemann Pick type C (NPC) causes neurodegeneration owing primarily to loss of NPC1. Here, we employed a Drosophila model to test links between glycosphingolipids, neurotransmission and neurodegeneration. We found that Npc1a nulls had elevated neurotransmission at the glutamatergic neuromuscular junction (NMJ), which was phenocopied in brainiac (brn) mutants, impairing mannosyl glucosylceramide (MacCer) glycosylation. Npc1a; brn double mutants had the same elevated synaptic transmission, suggesting that Npc1a and brn function within the same pathway. Glucosylceramide (GlcCer) synthase inhibition with miglustat prevented elevated neurotransmission in Npc1a and brn mutants, further suggesting epistasis. Synaptic MacCer did not accumulate in the NPC model, but GlcCer levels were increased, suggesting that GlcCer is responsible for the elevated synaptic transmission. Null Npc1a mutants had heightened neurodegeneration, but no significant motor neuron or glial cell death, indicating that dying cells are interneurons and that elevated neurotransmission precedes neurodegeneration. Glycosphingolipid synthesis mutants also had greatly heightened neurodegeneration, with similar neurodegeneration in Npc1a; brn double mutants, again suggesting that Npc1a and brn function in the same pathway. These findings indicate causal links between glycosphingolipid-dependent neurotransmission and neurodegeneration in this NPC disease model.
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Affiliation(s)
- Anna E. Eberwein
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - Swarat S. Kulkarni
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - Emma Rushton
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
- Department of Cell and Developmental Biology, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
- Vanderbilt Brain Institute, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
- Kennedy Center for Research on Human Development, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
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11
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Montagner PSS, Medeiros W, da Silva LCR, Borges CN, Brasil-Neto J, de Deus Silva Barbosa V, Caixeta FV, Malcher-Lopes R. Individually tailored dosage regimen of full-spectrum Cannabis extracts for autistic core and comorbid symptoms: a real-life report of multi-symptomatic benefits. Front Psychiatry 2023; 14:1210155. [PMID: 37671290 PMCID: PMC10475955 DOI: 10.3389/fpsyt.2023.1210155] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 07/24/2023] [Indexed: 09/07/2023] Open
Abstract
Autism Spectrum Disorders (ASD) may significantly impact the well-being of patients and their families. The therapeutic use of cannabis for ASD has gained interest due to its promising results and low side effects, but a consensus on treatment guidelines is lacking. In this study, we conducted a retrospective analysis of 20 patients with autistic symptoms who were treated with full-spectrum cannabis extracts (FCEs) in a response-based, individually-tailored dosage regimen. The daily dosage and relative proportions of cannabidiol (CBD) and tetrahydrocannabinol (THC) were adjusted based on treatment results following periodic clinical evaluation. Most patients (80%) were treated for a minimum of 6 months. We have used a novel, detailed online patient- or caregiver-reported outcome survey that inquired about core and comorbid symptoms, and quality of life. We also reviewed patients' clinical files, and no individual condition within the autistic spectrum was excluded. This real-life approach enabled us to gain a clearer appraisal of the ample scope of benefits that FCEs can provide for ASD patients and their families. Eighteen patients started with a CBD-rich FCE titrating protocol, and in three of them, the CBD-rich (CBD-dominant) FCE was gradually complemented with low doses of a THC-rich (THC-dominant) FCE based on observed effects. Two other patients have used throughout treatment a blend of two FCEs, one CBD-rich and the other THC-rich. The outcomes were mainly positive for most symptoms, and only one patient from each of the two above-mentioned situations displayed important side effects one who has used only CBD-rich FCE throughout the treatment, and another who has used a blend of CBD-Rich and THC-rich FCEs. Therefore, after FCE treatment, 18 out of 20 patients showed improvement in most core and comorbid symptoms of autism, and in quality of life for patients and their families. For them, side effects were mild and infrequent. Additionally, we show, for the first time, that allotriophagy (Pica) can be treated by FCEs. Other medications were reduced or completely discontinued in most cases. Based on our findings, we propose guidelines for individually tailored dosage regimens that may be adapted to locally available qualified FCEs and guide further clinical trials.
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Affiliation(s)
| | - Wesley Medeiros
- Laboratory of Neuroscience and Behavior, Department of Physiological Sciences, Institute of Biological Sciences, University of Brasilia, Brasília, Brazil
| | - Leandro Cruz Ramires da Silva
- Clinical Hospital, Federal University of Minas Gerais, Belo Horizonte, Brazil
- Brazilian Association of Medical Cannabis Patients, Ama-Me, Belo Horizonte, Brazil
| | - Clarissa Nogueira Borges
- Specialized Educational Care Division for Gifted Students of the Department of Education of the Federal District, Brasília, Brazil
| | | | - Vinícius de Deus Silva Barbosa
- Medical Cannabis Center–Syrian-Lebanese Hospital, São Paulo, Brazil
- National Association for Inclusion of the Autistic People, São Paulo, Brazil
| | - Fabio V. Caixeta
- Laboratory of Neuroscience and Behavior, Department of Physiological Sciences, Institute of Biological Sciences, University of Brasilia, Brasília, Brazil
| | - Renato Malcher-Lopes
- Laboratory of Neuroscience and Behavior, Department of Physiological Sciences, Institute of Biological Sciences, University of Brasilia, Brasília, Brazil
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12
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Pilotto F, Douthwaite C, Diab R, Ye X, Al Qassab Z, Tietje C, Mounassir M, Odriozola A, Thapa A, Buijsen RAM, Lagache S, Uldry AC, Heller M, Müller S, van Roon-Mom WMC, Zuber B, Liebscher S, Saxena S. Early molecular layer interneuron hyperactivity triggers Purkinje neuron degeneration in SCA1. Neuron 2023; 111:2523-2543.e10. [PMID: 37321222 PMCID: PMC10431915 DOI: 10.1016/j.neuron.2023.05.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 03/17/2023] [Accepted: 05/17/2023] [Indexed: 06/17/2023]
Abstract
Toxic proteinaceous deposits and alterations in excitability and activity levels characterize vulnerable neuronal populations in neurodegenerative diseases. Using in vivo two-photon imaging in behaving spinocerebellar ataxia type 1 (Sca1) mice, wherein Purkinje neurons (PNs) degenerate, we identify an inhibitory circuit element (molecular layer interneurons [MLINs]) that becomes prematurely hyperexcitable, compromising sensorimotor signals in the cerebellum at early stages. Mutant MLINs express abnormally elevated parvalbumin, harbor high excitatory-to-inhibitory synaptic density, and display more numerous synaptic connections on PNs, indicating an excitation/inhibition imbalance. Chemogenetic inhibition of hyperexcitable MLINs normalizes parvalbumin expression and restores calcium signaling in Sca1 PNs. Chronic inhibition of mutant MLINs delayed PN degeneration, reduced pathology, and ameliorated motor deficits in Sca1 mice. Conserved proteomic signature of Sca1 MLINs, shared with human SCA1 interneurons, involved the higher expression of FRRS1L, implicated in AMPA receptor trafficking. We thus propose that circuit-level deficits upstream of PNs are one of the main disease triggers in SCA1.
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Affiliation(s)
- Federica Pilotto
- Department of Neurology, Inselspital University Hospital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Christopher Douthwaite
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians University Munich, Martinsried, Germany
| | - Rim Diab
- Department of Neurology, Inselspital University Hospital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - XiaoQian Ye
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians University Munich, Martinsried, Germany
| | - Zahraa Al Qassab
- Department of Neurology, Inselspital University Hospital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Christoph Tietje
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians University Munich, Martinsried, Germany
| | - Meriem Mounassir
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians University Munich, Martinsried, Germany
| | | | - Aishwarya Thapa
- Department of Neurology, Inselspital University Hospital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Ronald A M Buijsen
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Sophie Lagache
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Anne-Christine Uldry
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Manfred Heller
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Stefan Müller
- Flow Cytometry and Cell sorting, Department for BioMedical Research, University of Bern, Bern, Switzerland
| | | | - Benoît Zuber
- Institute of Anatomy, University of Bern, Bern, Switzerland
| | - Sabine Liebscher
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians University Munich, Martinsried, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany; University Hospital Cologne, Deptartment of Neurology, Cologne, Germany.
| | - Smita Saxena
- Department of Neurology, Inselspital University Hospital, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland.
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13
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Gredell M, Lu J, Zuo Y. The effect of single-cell knockout of Fragile X Messenger Ribonucleoprotein on synaptic structural plasticity. Front Synaptic Neurosci 2023; 15:1135479. [PMID: 37035256 PMCID: PMC10076639 DOI: 10.3389/fnsyn.2023.1135479] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 03/07/2023] [Indexed: 04/11/2023] Open
Abstract
Fragile X Syndrome (FXS) is the best-known form of inherited intellectual disability caused by the loss-of-function mutation in a single gene. The FMR1 gene mutation abolishes the expression of Fragile X Messenger Ribonucleoprotein (FMRP), which regulates the expression of many synaptic proteins. Cortical pyramidal neurons in postmortem FXS patient brains show abnormally high density and immature morphology of dendritic spines; this phenotype is replicated in the Fmr1 knockout (KO) mouse. While FMRP is well-positioned in the dendrite to regulate synaptic plasticity, intriguing in vitro and in vivo data show that wild type neurons embedded in a network of Fmr1 KO neurons or glia exhibit spine abnormalities just as neurons in Fmr1 global KO mice. This raises the question: does FMRP regulate synaptic morphology and dynamics in a cell-autonomous manner, or do the synaptic phenotypes arise from abnormal pre-synaptic inputs? To address this question, we combined viral and mouse genetic approaches to delete FMRP from a very sparse subset of cortical layer 5 pyramidal neurons (L5 PyrNs) either during early postnatal development or in adulthood. We then followed the structural dynamics of dendritic spines on these Fmr1 KO neurons by in vivo two-photon microscopy. We found that, while L5 PyrNs in adult Fmr1 global KO mice have abnormally high density of thin spines, single-cell Fmr1 KO in adulthood does not affect spine density, morphology, or dynamics. On the contrary, neurons with neonatal FMRP deletion have normal spine density but elevated spine formation at 1 month of age, replicating the phenotype in Fmr1 global KO mice. Interestingly, these neurons exhibit elevated thin spine density, but normal total spine density, by adulthood. Together, our data reveal cell-autonomous FMRP regulation of cortical synaptic dynamics during adolescence, but spine defects in adulthood also implicate non-cell-autonomous factors.
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Affiliation(s)
| | | | - Yi Zuo
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA, United States
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14
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Altered integration of excitatory inputs onto the basal dendrites of layer 5 pyramidal neurons in a mouse model of Fragile X syndrome. Proc Natl Acad Sci U S A 2023; 120:e2208963120. [PMID: 36595706 PMCID: PMC9926222 DOI: 10.1073/pnas.2208963120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Layer 5 (L5) pyramidal neurons receive predictive and sensory inputs in a compartmentalized manner at their apical and basal dendrites, respectively. To uncover how integration of sensory inputs is affected in autism spectrum disorders (ASD), we used two-photon glutamate uncaging to activate spines in the basal dendrites of L5 pyramidal neurons from a mouse model of Fragile X syndrome (FXS), the most common genetic cause of ASD. While subthreshold excitatory inputs integrate linearly in wild-type animals, surprisingly those with FXS summate sublinearly, contradicting what would be expected of sensory hypersensitivity classically associated with ASD. We next investigated the mechanism underlying this sublinearity by performing knockdown of the regulatory β4 subunit of BK channels, which rescued the synaptic integration, a result that was corroborated with numerical simulations. Taken together, these findings suggest that there is a differential impairment in the integration of feedforward sensory and feedback predictive inputs in L5 pyramidal neurons in FXS and potentially other forms of ASD, as a result of specifically localized subcellular channelopathies. These results challenge the traditional view that FXS and other ASD are characterized by sensory hypersensitivity, proposing instead a hyposensitivity of sensory inputs and hypersensitivity of predictive inputs onto cortical neurons.
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15
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Speranza L, Filiz KD, Goebel S, Perrone-Capano C, Pulcrano S, Volpicelli F, Francesconi A. Combined DiI and Antibody Labeling Reveals Complex Dysgenesis of Hippocampal Dendritic Spines in a Mouse Model of Fragile X Syndrome. Biomedicines 2022; 10:2692. [PMID: 36359212 PMCID: PMC9687937 DOI: 10.3390/biomedicines10112692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 11/30/2022] Open
Abstract
Structural, functional, and molecular alterations in excitatory spines are a common hallmark of many neurodevelopmental disorders including intellectual disability and autism. Here, we describe an optimized methodology, based on combined use of DiI and immunofluorescence, for rapid and sensitive characterization of the structure and composition of spines in native brain tissue. We successfully demonstrate the applicability of this approach by examining the properties of hippocampal spines in juvenile Fmr1 KO mice, a mouse model of Fragile X Syndrome. We find that mutant mice display pervasive dysgenesis of spines evidenced by an overabundance of both abnormally elongated thin spines and cup-shaped spines, in combination with reduced density of mushroom spines. We further find that mushroom spines expressing the actin-binding protein Synaptopodin-a marker for spine apparatus-are more prevalent in mutant mice. Previous work identified spines with Synaptopodin/spine apparatus as the locus of mGluR-LTD, which is abnormally elevated in Fmr1 KO mice. Altogether, our data suggest this enhancement may be linked to the preponderance of this subset of spines in the mutant. Overall, these findings demonstrate the sensitivity and versatility of the optimized methodology by uncovering a novel facet of spine dysgenesis in Fmr1 KO mice.
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Affiliation(s)
- Luisa Speranza
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Kardelen Dalım Filiz
- Department of Pharmacy, School of Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy
| | - Sarah Goebel
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Carla Perrone-Capano
- Department of Pharmacy, School of Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy
| | - Salvatore Pulcrano
- Institute of Genetics and Biophysics “A. Buzzati-Traverso”, C.N.R., 80131 Naples, Italy
| | - Floriana Volpicelli
- Department of Pharmacy, School of Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy
| | - Anna Francesconi
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461, USA
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16
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Miles KD, Doll CA. Chloride imbalance in Fragile X syndrome. Front Neurosci 2022; 16:1008393. [PMID: 36312023 PMCID: PMC9596984 DOI: 10.3389/fnins.2022.1008393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 09/20/2022] [Indexed: 11/26/2022] Open
Abstract
Developmental changes in ionic balance are associated with crucial hallmarks in neural circuit formation, including changes in excitation and inhibition, neurogenesis, and synaptogenesis. Neuronal excitability is largely mediated by ionic concentrations inside and outside of the cell, and chloride (Cl-) ions are highly influential in early neurodevelopmental events. For example, γ-aminobutyric acid (GABA) is the main inhibitory neurotransmitter of the mature central nervous system (CNS). However, during early development GABA can depolarize target neurons, and GABAergic depolarization is implicated in crucial neurodevelopmental processes. This developmental shift of GABAergic neurotransmission from depolarizing to hyperpolarizing output is induced by changes in Cl- gradients, which are generated by the relative expression of Cl- transporters Nkcc1 and Kcc2. Interestingly, the GABA polarity shift is delayed in Fragile X syndrome (FXS) models; FXS is one of the most common heritable neurodevelopmental disorders. The RNA binding protein FMRP, encoded by the gene Fragile X Messenger Ribonucleoprotein-1 (Fmr1) and absent in FXS, appears to regulate chloride transporter expression. This could dramatically influence FXS phenotypes, as the syndrome is hypothesized to be rooted in defects in neural circuit development and imbalanced excitatory/inhibitory (E/I) neurotransmission. In this perspective, we summarize canonical Cl- transporter expression and investigate altered gene and protein expression of Nkcc1 and Kcc2 in FXS models. We then discuss interactions between Cl- transporters and neurotransmission complexes, and how these links could cause imbalances in inhibitory neurotransmission that may alter mature circuits. Finally, we highlight current therapeutic strategies and promising new directions in targeting Cl- transporter expression in FXS patients.
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Affiliation(s)
| | - Caleb Andrew Doll
- Department of Pediatrics, Section of Developmental Biology, University of Colorado School of Medicine, Children’s Hospital Colorado, Aurora, CO, United States
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17
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Ramón-Landreau M, Sánchez-Puelles C, López-Sánchez N, Lozano-Ureña A, Llabrés-Mas AM, Frade JM. E2F4DN Transgenic Mice: A Tool for the Evaluation of E2F4 as a Therapeutic Target in Neuropathology and Brain Aging. Int J Mol Sci 2022; 23:ijms232012093. [PMID: 36292945 PMCID: PMC9603043 DOI: 10.3390/ijms232012093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/04/2022] [Accepted: 10/05/2022] [Indexed: 12/03/2022] Open
Abstract
E2F4 was initially described as a transcription factor with a key function in the regulation of cell quiescence. Nevertheless, a number of recent studies have established that E2F4 can also play a relevant role in cell and tissue homeostasis, as well as tissue regeneration. For these non-canonical functions, E2F4 can also act in the cytoplasm, where it is able to interact with many homeostatic and synaptic regulators. Since E2F4 is expressed in the nervous system, it may fulfill a crucial role in brain function and homeostasis, being a promising multifactorial target for neurodegenerative diseases and brain aging. The regulation of E2F4 is complex, as it can be chemically modified through acetylation, from which we present evidence in the brain, as well as methylation, and phosphorylation. The phosphorylation of E2F4 within a conserved threonine motif induces cell cycle re-entry in neurons, while a dominant negative form of E2F4 (E2F4DN), in which the conserved threonines have been substituted by alanines, has been shown to act as a multifactorial therapeutic agent for Alzheimer’s disease (AD). We generated transgenic mice neuronally expressing E2F4DN. We have recently shown using this mouse strain that expression of E2F4DN in 5xFAD mice, a known murine model of AD, improved cognitive function, reduced neuronal tetraploidization, and induced a transcriptional program consistent with modulation of amyloid-β (Aβ) peptide proteostasis and brain homeostasis recovery. 5xFAD/E2F4DN mice also showed reduced microgliosis and astrogliosis in both the cerebral cortex and hippocampus at 3-6 months of age. Here, we analyzed the immune response in 1 year-old 5xFAD/E2F4DN mice, concluding that reduced microgliosis and astrogliosis is maintained at this late stage. In addition, the expression of E2F4DN also reduced age-associated microgliosis in wild-type mice, thus stressing its role as a brain homeostatic agent. We conclude that E2F4DN transgenic mice represent a promising tool for the evaluation of E2F4 as a therapeutic target in neuropathology and brain aging.
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Affiliation(s)
- Morgan Ramón-Landreau
- Department of Molecular, Cellular and Developmental Neurobiology, Cajal Institute, Consejo Superior de Investigaciones Científicas, 28002 Madrid, Spain
| | - Cristina Sánchez-Puelles
- Department of Molecular, Cellular and Developmental Neurobiology, Cajal Institute, Consejo Superior de Investigaciones Científicas, 28002 Madrid, Spain
| | - Noelia López-Sánchez
- Department of Molecular, Cellular and Developmental Neurobiology, Cajal Institute, Consejo Superior de Investigaciones Científicas, 28002 Madrid, Spain
| | - Anna Lozano-Ureña
- Department of Molecular, Cellular and Developmental Neurobiology, Cajal Institute, Consejo Superior de Investigaciones Científicas, 28002 Madrid, Spain
| | - Aina M. Llabrés-Mas
- Department of Molecular, Cellular and Developmental Neurobiology, Cajal Institute, Consejo Superior de Investigaciones Científicas, 28002 Madrid, Spain
| | - José M. Frade
- Department of Molecular, Cellular and Developmental Neurobiology, Cajal Institute, Consejo Superior de Investigaciones Científicas, 28002 Madrid, Spain
- Cajal International Neuroscience Center, Consejo Superior de Investigaciones Científicas, UAH Science and Technology Campus, Avenida León 1, 28805 Alcalá de Henares, Spain
- Correspondence: ; Tel.: +34-91-585-4740
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18
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Shing N, Walker MC, Chang P. The Role of Aberrant Neural Oscillations in the Hippocampal-Medial Prefrontal Cortex Circuit in Neurodevelopmental and Neurological Disorders. Neurobiol Learn Mem 2022; 195:107683. [PMID: 36174886 DOI: 10.1016/j.nlm.2022.107683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 09/09/2022] [Accepted: 09/20/2022] [Indexed: 11/30/2022]
Abstract
The hippocampus (HPC) and medial prefrontal cortex (mPFC) have well-established roles in cognition, emotion, and sensory processing. In recent years, interests have shifted towards developing a deeper understanding of the mechanisms underlying interactions between the HPC and mPFC in achieving these functions. Considerable research supports the idea that synchronized activity between the HPC and the mPFC is a general mechanism by which brain functions are regulated. In this review, we summarize current knowledge on the hippocampal-medial prefrontal cortex (HPC-mPFC) circuit in normal brain function with a focus on oscillations and highlight several neurodevelopmental and neurological disorders associated with aberrant HPC-mPFC circuitry. We further discuss oscillatory dynamics across the HPC-mPFC circuit as potentially useful biomarkers to assess interventions for neurodevelopmental and neurological disorders. Finally, advancements in brain stimulation, gene therapy and pharmacotherapy are explored as promising therapies for disorders with aberrant HPC-mPFC circuit dynamics.
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Affiliation(s)
- Nathanael Shing
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, WC1N 3BG, UK; Department of Medicine, University of Central Lancashire, Preston, PR17BH, UK
| | - Matthew C Walker
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Pishan Chang
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, WC1E 6BT.
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19
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Lipid-Based Molecules on Signaling Pathways in Autism Spectrum Disorder. Int J Mol Sci 2022; 23:ijms23179803. [PMID: 36077195 PMCID: PMC9456412 DOI: 10.3390/ijms23179803] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/22/2022] [Accepted: 08/23/2022] [Indexed: 11/16/2022] Open
Abstract
The signaling pathways associated with lipid metabolism contribute to the pathophysiology of autism spectrum disorder (ASD) and provide insights for devising new therapeutic strategies. Prostaglandin E2 is a membrane-derived lipid molecule that contributes to developing ASD associated with canonical Wnt signaling. Cyclooxygenase-2 plays a key role in neuroinflammation and is implicated in the pathogenesis of neurodevelopmental diseases, such as ASD. The endocannabinoid system maintains a balance between inflammatory and redox status and synaptic plasticity and is a potential target for ASD pathophysiology. Redox signaling refers to specific and usually reversible oxidation–reduction reactions, some of which are also involved in pathways accounting for the abnormal behavior observed in ASD. Redox signaling and redox status-sensitive transcription factors contribute to the pathophysiology of ASD. Cannabinoids regulate the redox balance by altering the levels and activity of antioxidant molecules via ROS-producing NADPH oxidase (NOX) and ROS-scavenging superoxide dismutase enzymes. These signaling cascades integrate a broad range of neurodevelopmental processes that may be involved in the pathophysiology of ASD. Based on these pathways, we highlight putative targets that may be used for devising novel therapeutic interventions for ASD.
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20
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Beyond controlling cell size: functional analyses of S6K in tumorigenesis. Cell Death Dis 2022; 13:646. [PMID: 35879299 PMCID: PMC9314331 DOI: 10.1038/s41419-022-05081-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 07/05/2022] [Accepted: 07/07/2022] [Indexed: 01/21/2023]
Abstract
As a substrate and major effector of the mammalian target of rapamycin complex 1 (mTORC1), the biological functions of ribosomal protein S6 kinase (S6K) have been canonically assigned for cell size control by facilitating mRNA transcription, splicing, and protein synthesis. However, accumulating evidence implies that diverse stimuli and upstream regulators modulate S6K kinase activity, leading to the activation of a plethora of downstream substrates for distinct pathobiological functions. Beyond controlling cell size, S6K simultaneously plays crucial roles in directing cell apoptosis, metabolism, and feedback regulation of its upstream signals. Thus, we comprehensively summarize the emerging upstream regulators, downstream substrates, mouse models, clinical relevance, and candidate inhibitors for S6K and shed light on S6K as a potential therapeutic target for cancers.
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