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Qian J, Zheng L, Huang M, Zhao M. Potential Mechanisms of Casein Hexapeptide YPVEPF on Stress-Induced Anxiety and Insomnia Mice and Its Molecular Effects and Key Active Structure. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:6189-6202. [PMID: 38501577 DOI: 10.1021/acs.jafc.3c05718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
The hexapeptide YPVEPF with strong sleep-enhancing effects could be detected in rat brain after a single oral administration as we previously proved. In this study, the mechanism and molecular effects of YPVEPF in the targeted stress-induced anxiety mice were first investigated, and its key active structure was further explored. The results showed that YPVEPF could significantly prolong sleep duration and improve the anxiety indexes, including prolonging the time spent in the open arms and in the center. Meanwhile, YPVEPF showed strong sleep-enhancing effects by significantly increasing the level of the GABA/Glu ratio, 5-HT, and dopamine in brain and serum and regulating the anabolism of multiple targets, but the effects could be blocked by bicuculline and WAY100135. Moreover, the molecular simulation results showed that YPVEPF could stably bind to the vital GABAA and 5-HT1A receptors due to the vital structure of Tyr-Pro-Xaa-Xaa-Pro-, and the electrostatic and van der Waals energy played dominant roles in stabilizing the conformation. Therefore, YPVEPF displayed sleep-enhancing and anxiolytic effects by regulating the GABA-Glu metabolic pathway and serotoninergic system depending on distinctive self-folding structures with Tyr and two Pro repeats.
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Affiliation(s)
- Jingjing Qian
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Lin Zheng
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
- Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou 510650, China
- Guangdong Huapeptides Biotechnology Co., Ltd, Zhaoqing 526000, China
| | - Mingtao Huang
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Mouming Zhao
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
- Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou 510650, China
- Food Laboratory of Zhongyuan, Luohe, Henan 462300, China
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Ün D, Kovalchuk V, El-Kasaby A, Kasture A, Koban F, Kudlacek O, Freissmuth M, Sucic S. Breaking the rules of SLC6 transporters: Export of the human creatine transporter-1 from the endoplasmic reticulum is supported by its N-terminus. J Neurochem 2024. [PMID: 38419374 DOI: 10.1111/jnc.16088] [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: 12/19/2023] [Revised: 02/13/2024] [Accepted: 02/15/2024] [Indexed: 03/02/2024]
Abstract
Mutations in the human creatine transporter 1 (CRT1/SLC6A8) cause the creatine transporter deficiency syndrome, which is characterized by intellectual disability, epilepsy, autism, and developmental delay. The vast majority of mutations cause protein misfolding and hence reduce cell surface expression. Hence, it is important to understand the molecular machinery supporting folding and export of CRT1 from the endoplasmic reticulum (ER). All other SLC6 members thus far investigated rely on a C-terminal motif for binding the COPII-component SEC24 to drive their ER export; their N-termini are dispensable. Here, we show that, in contrast, in CRT1 the C-terminal ER-export motif is cryptic and it is the N-terminus, which supports ER export. This conclusion is based on the following observations: (i) siRNA-induced depletion of individual SEC24 isoforms revealed that CRT1 relied on SEC24C for ER export. However, mutations of the C-terminal canonical ER-export motif of CRT1 did not impair its cell surface delivery. (ii) Nevertheless, the C-terminal motif of CRT1 was operational in a chimeric protein comprising the serotonin transporter (SERT/SLC6A4) and the C-terminus of CRT1. (iii) Tagging of the N-terminus-but not the C-terminus-with yellow fluorescent protein (YFP) resulted in ER retention. (iv) Serial truncations of the N-terminus showed that removal of ≥51 residues of CRT1 impaired surface delivery, because the truncated CRT1 were confined to the ER. (v) Mutation of P51 to alanine also reduced cell surface delivery of CRT1 and relieved its dependence on SEC24C. Thus, the ER-export motif in the N-terminus of CRT1 overrides the canonical C-terminal motif.
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Affiliation(s)
- Didem Ün
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Centre of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Vasylyna Kovalchuk
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Centre of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Ali El-Kasaby
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Centre of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Ameya Kasture
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Centre of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna, Austria
| | - Florian Koban
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Centre of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Oliver Kudlacek
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Centre of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Centre of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Sonja Sucic
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Centre of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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Zhao X, He Z, Li Y, Yang X, Li B. Atypical absence seizures and gene variants: A gene-based review of etiology, electro-clinical features, and associated epilepsy syndrome. Epilepsy Behav 2024; 151:109636. [PMID: 38232560 DOI: 10.1016/j.yebeh.2024.109636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/01/2024] [Accepted: 01/05/2024] [Indexed: 01/19/2024]
Abstract
Atypical absence seizures are generalized non-convulsive seizures that often occur in children with cognitive impairment. They are common in refractory epilepsy and have been recognized as one of the hallmarks of developmental epileptic encephalopathies. Notably, pathogenic variants associated with AAS, such as GABRG2, GABRG3, SLC6A1, CACNB4, SCN8A, and SYNGAP1, are also linked to developmental epileptic encephalopathies. Atypical absences differ from typical absences in that they are frequently drug-resistant and the prognosis is dependent on the etiology or related epileptic syndromes. To improve clinicians' understanding of atypical absences and provide novel perspectives for clinical treatment, we have reviewed the electro-clinical characteristics, etiologies, treatment, and prognosis of atypical absences, with a focus on the etiology of advancements in gene variants, shedding light on potential avenues for improved clinical management.
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Affiliation(s)
| | - Zimeng He
- Shandong University, Jinan, Shandong, China
| | - Yumei Li
- Shandong University, Jinan, Shandong, China
| | - Xiaofan Yang
- Shandong University, Jinan, Shandong, China; Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, Shandong, China.
| | - Baomin Li
- Shandong University, Jinan, Shandong, China; Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, Shandong, China.
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Trivisano M, Butera A, Quintavalle C, De Dominicis A, Calabrese C, Cappelletti S, Vigevano F, Novelli A, Specchio N. Insights into cognitive and behavioral comorbidities of SLC6A1-related epilepsy: five new cases and literature review. Front Neurosci 2023; 17:1215684. [PMID: 37700749 PMCID: PMC10493279 DOI: 10.3389/fnins.2023.1215684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 08/04/2023] [Indexed: 09/14/2023] Open
Abstract
Introduction SLC6A1 pathogenic variants have been associated with epilepsy and neurodevelopmental disorders. The clinical phenotype includes different seizure types, intellectual disability, and psychiatric symptoms affecting mood and behavior. Few data regarding neuropsychological features have been described, and details on cognitive profiles are often missing due to the lack of standardized tests. Methods We retrospectively reviewed the neuropsychological assessments of five subjects carrying heterozygous missense genetic variants in SLC6A1. We also collected data on epileptic features, EEGs, and brain MRIs. Additionally, we reviewed neuropsychological data from 204 previously reported patients with SLC6A1 pathogenic variants. Results In our series, at the last evaluation (median 12.6 years), three patients had borderline intellectual functioning, one patient had mild cognitive impairment, and one patient presented with a moderate cognitive disability. Three out of five patients underwent at least two neuropsychological evaluations, which revealed a worsening of cognitive functions over time. We detected attention deficits in all patients. In addition, we observed anxiety, disruptive behavior disorder, emotional instability, and hetero aggressiveness. We also performed a literature review that highlighted that most of the patients with SLC6A1 pathogenic variants have mild-to-moderate intellectual disability and that one-third of cases have autistic traits. Discussion Based on the literature review and the detailed description of our cases, we conclude that patients with SLC6A1-related epilepsy mostly present with mild-to-moderate intellectual disability, often associated with attention disorders. Such symptoms may worsen over time. Periodic standardized neuropsychological tests may be useful tools to follow development over time, and patient-specific rehabilitation programs could be tailored consistently.
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Affiliation(s)
- Marina Trivisano
- Clinical and Experimental Neurology, Bambino Gesù Children’s Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy
| | - Ambra Butera
- Clinical and Experimental Neurology, Bambino Gesù Children’s Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental age “Gaetano Barresi”, University of Messina, Messina, Italy
- PROMISE Department, School of Child Neurology and Psychiatry, University of Palermo, Palermo, Italy
| | - Chiara Quintavalle
- Clinical and Experimental Neurology, Bambino Gesù Children’s Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy
| | - Angela De Dominicis
- Clinical and Experimental Neurology, Bambino Gesù Children’s Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Costanza Calabrese
- Clinical and Experimental Neurology, Bambino Gesù Children’s Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy
| | - Simona Cappelletti
- Clinical and Experimental Neurology, Bambino Gesù Children’s Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy
| | - Federico Vigevano
- Clinical and Experimental Neurology, Bambino Gesù Children’s Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy
| | - Antonio Novelli
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Nicola Specchio
- Clinical and Experimental Neurology, Bambino Gesù Children’s Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy
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Asuncion JD, Eamani A, Rohrbach EW, Knapp EM, Deshpande SA, Bonanno SL, Murphy JE, Lawal HO, Krantz DE. Precise CRISPR-Cas9-mediated mutation of a membrane trafficking domain in the Drosophila vesicular monoamine transporter gene. Curr Res Physiol 2023; 6:100101. [PMID: 37409154 PMCID: PMC10318446 DOI: 10.1016/j.crphys.2023.100101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 05/16/2023] [Accepted: 06/19/2023] [Indexed: 07/07/2023] Open
Abstract
Monoamine neurotransmitters such as noradrenalin are released from both synaptic vesicles (SVs) and large dense-core vesicles (LDCVs), the latter mediating extrasynaptic signaling. The contribution of synaptic versus extrasynaptic signaling to circuit function and behavior remains poorly understood. To address this question, we have previously used transgenes encoding a mutation in the Drosophila Vesicular Monoamine Transporter (dVMAT) that shifts amine release from SVs to LDCVs. To circumvent the use of transgenes with non-endogenous patterns of expression, we have now used CRISPR-Cas9 to generate a trafficking mutant in the endogenous dVMAT gene. To minimize disruption of the dVMAT coding sequence and a nearby RNA splice site, we precisely introduced a point mutation using single-stranded oligonucleotide repair. A predicted decrease in fertility was used as a phenotypic screen to identify founders in lieu of a visible marker. Phenotypic analysis revealed a defect in the ovulation of mature follicles and egg retention in the ovaries. We did not detect defects in the contraction of lateral oviducts following optogenetic stimulation of octopaminergic neurons. Our findings suggest that release of mature eggs from the ovary is disrupted by changing the balance of VMAT trafficking between SVs and LDCVs. Further experiments using this model will help determine the mechanisms that sensitize specific circuits to changes in synaptic versus extrasynaptic signaling.
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Affiliation(s)
- James D. Asuncion
- Medical Scientist Training Program, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
- UCLA Neuroscience Interdepartmental Program, University of California, Los Angeles, CA, 90095, USA
| | - Aditya Eamani
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Ethan W. Rohrbach
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
- UCLA Neuroscience Interdepartmental Program, University of California, Los Angeles, CA, 90095, USA
| | - Elizabeth M. Knapp
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Sonali A. Deshpande
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Shivan L. Bonanno
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Jeremy E. Murphy
- Department of Biological Sciences, Delaware State University, Dover, DE, USA, 19901, USA
| | - Hakeem O. Lawal
- Department of Biological Sciences, Delaware State University, Dover, DE, USA, 19901, USA
| | - David E. Krantz
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
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Fogarty MJ. Inhibitory Synaptic Influences on Developmental Motor Disorders. Int J Mol Sci 2023; 24:ijms24086962. [PMID: 37108127 PMCID: PMC10138861 DOI: 10.3390/ijms24086962] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/05/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
During development, GABA and glycine play major trophic and synaptic roles in the establishment of the neuromotor system. In this review, we summarise the formation, function and maturation of GABAergic and glycinergic synapses within neuromotor circuits during development. We take special care to discuss the differences in limb and respiratory neuromotor control. We then investigate the influences that GABAergic and glycinergic neurotransmission has on two major developmental neuromotor disorders: Rett syndrome and spastic cerebral palsy. We present these two syndromes in order to contrast the approaches to disease mechanism and therapy. While both conditions have motor dysfunctions at their core, one condition Rett syndrome, despite having myriad symptoms, has scientists focused on the breathing abnormalities and their alleviation-to great clinical advances. By contrast, cerebral palsy remains a scientific quagmire or poor definitions, no widely adopted model and a lack of therapeutic focus. We conclude that the sheer abundance of diversity of inhibitory neurotransmitter targets should provide hope for intractable conditions, particularly those that exhibit broad spectra of dysfunction-such as spastic cerebral palsy and Rett syndrome.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55902, USA
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7
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Neurotransmitters in Prevention and Treatment of Alzheimer's Disease. Int J Mol Sci 2023; 24:ijms24043841. [PMID: 36835251 PMCID: PMC9966535 DOI: 10.3390/ijms24043841] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/17/2023] Open
Abstract
Alzheimer's disease (AD) is the most frequent cause of cognitive impairment in middle-aged and older populations. There is a lack of drugs that demonstrate significant efficacy in AD, so the study of the pathogenesis of AD is of great importance. More efficacious interventions are needed, as reflected by our population's fast aging. Synaptic plasticity is the capacity of neurons to adjust their connections, and it is strongly tied to learning and memory, cognitive function, and brain injury recovery. Changes in synaptic strength, such as long-term potentiation (LTP) or inhibition (LTD), are thought to represent the biological foundation of the early stages of learning and memory. The results of numerous studies confirm that neurotransmitters and their receptors play an important role in the regulation of synaptic plasticity. However, so far, there is no definite correlation between the function of neurotransmitters in aberrant neural oscillation and AD-related cognitive impairment. We summarized the AD process to understand the impact of neurotransmitters in the progression and pathogenesis of AD, including the current status of neurotransmitter target drugs, and the latest evidence of neurotransmitters' function and changes in the AD process.
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Kasture AS, Fischer FP, Kunert L, Burger ML, Burgstaller AC, El-Kasaby A, Hummel T, Sucic S. Drosophila melanogaster as a model for unraveling unique molecular features of epilepsy elicited by human GABA transporter 1 variants. Front Neurosci 2023; 16:1074427. [PMID: 36741049 PMCID: PMC9893286 DOI: 10.3389/fnins.2022.1074427] [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: 10/19/2022] [Accepted: 12/21/2022] [Indexed: 01/20/2023] Open
Abstract
Mutations in the human γ-aminobutyric acid (GABA) transporter 1 (hGAT-1) can instigate myoclonic-atonic and other generalized epilepsies in the afflicted individuals. We systematically examined fifteen hGAT-1 disease variants, all of which dramatically reduced or completely abolished GABA uptake activity. Many of these loss-of-function variants were absent from their regular site of action at the cell surface, due to protein misfolding and/or impaired trafficking machinery (as verified by confocal microscopy and de-glycosylation experiments). A modest fraction of the mutants displayed correct targeting to the plasma membrane, but nonetheless rendered the mutated proteins devoid of GABA transport, possibly due to structural alterations in the GABA binding site/translocation pathway. We here focused on a folding-deficient A288V variant. In flies, A288V reiterated its impeded expression pattern, closely mimicking the ER-retention demonstrated in transfected HEK293 cells. Functionally, A288V presented a temperature-sensitive seizure phenotype in fruit flies. We employed diverse small molecules to restore the expression and activity of folding-deficient hGAT-1 epilepsy variants, in vitro (in HEK293 cells) and in vivo (in flies). We identified three compounds (chemical and pharmacological chaperones) conferring moderate rescue capacity for several variants. Our data grant crucial new insights into: (i) the molecular basis of epilepsy in patients harboring hGAT-1 mutations, and (ii) a proof-of-principle that protein folding deficits in disease-associated hGAT-1 variants can be corrected using the pharmacochaperoning approach. Such innovative pharmaco-therapeutic prospects inspire the rational design of novel drugs for alleviating the clinical symptoms triggered by the numerous emerging pathogenic mutations in hGAT-1.
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Affiliation(s)
- Ameya S. Kasture
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria,Department of Neuroscience and Developmental Biology, University of Vienna, Vienna, Austria
| | - Florian P. Fischer
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria,Department of Epileptology and Neurology, University of Aachen, Aachen, Germany
| | - Lisa Kunert
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna, Austria
| | - Melanie L. Burger
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | | | - Ali El-Kasaby
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Thomas Hummel
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna, Austria
| | - Sonja Sucic
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria,*Correspondence: Sonja Sucic,
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Goodspeed K, Mosca LR, Weitzel NC, Horning K, Simon EW, Pfalzer AC, Xia M, Langer K, Freed A, Bone M, Picone M, Bichell TJV. A draft conceptual model of SLC6A1 neurodevelopmental disorder. Front Neurosci 2023; 16:1026065. [PMID: 36741059 PMCID: PMC9893116 DOI: 10.3389/fnins.2022.1026065] [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: 08/23/2022] [Accepted: 12/05/2022] [Indexed: 01/21/2023] Open
Abstract
Introduction SLC6A1 Neurodevelopmental Disorder (SLC6A1-NDD), first described in 2015, is a rare syndrome caused by a mutation in the SLC6A1 gene which encodes for the GABA Transporter 1 (GAT-1) protein. Epilepsy is one of the most common symptoms in patients and is often the primary treatment target, though the severity of epilepsy is variable. The impact of seizures and other symptoms of SLC6A1-NDD on patients and caregivers is wide-ranging and has not been described in a formal disease concept study. Methods A literature search was performed using the simple search term, "SLC6A1." Papers published before 2015, and those which did not describe the human neurodevelopmental disorder were removed from analysis. Open-ended interviews on lived experiences were conducted with two patient advocate key opinion leaders. An analysis of de-identified conversations between families of people with SLC6A1-NDD on social media was performed to quantify topics of concern. Results Published literature described symptoms in all of the following domains: neurological, visual, motor, cognitive, communication, behavior, gastrointestinal, sleep, musculo-skeletal, and emotional in addition to epilepsy. Key opinion leaders noted two unpublished features: altered hand use in infants, and developmental regression with onset of epilepsy. Analysis of social media interactions confirmed that the core symptoms of epilepsy and autistic traits were prominent concerns, but also demonstrated that other symptoms have a large impact on family life. Discussion For rare diseases, analysis of published literature is important, but may not be as comprehensive as that which can be gleaned from spontaneous interactions between families and through qualitative interviews. This report reflects our current understanding of the lived experience of SLC6A1-NDD. The discrepancy between the domains of disease reported in the literature and those discussed in patient conversations suggests that a formal qualitative interview-based disease concept study of SLC6A1-NDD is warranted.
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Affiliation(s)
- Kimberly Goodspeed
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States,*Correspondence: Kimberly Goodspeed,
| | - Lindsay R. Mosca
- College of Arts and Sciences, Vanderbilt University, Nashville, TN, United States
| | - Nicole C. Weitzel
- College of Arts and Sciences, Vanderbilt University, Nashville, TN, United States
| | | | - Elijah W. Simon
- College of Arts and Sciences, Vanderbilt University, Nashville, TN, United States
| | | | - Maya Xia
- COMBINEDBrain, Brentwood, TN, United States
| | - Katherine Langer
- College of Arts and Sciences, Vanderbilt University, Nashville, TN, United States
| | | | - Megan Bone
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Maria Picone
- TREND Community, Philadelphia, PA, United States
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Experimental and Bioinformatic Insights into the Effects of Epileptogenic Variants on the Function and Trafficking of the GABA Transporter GAT-1. Int J Mol Sci 2023; 24:ijms24020955. [PMID: 36674476 PMCID: PMC9862756 DOI: 10.3390/ijms24020955] [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: 11/29/2022] [Revised: 12/27/2022] [Accepted: 12/31/2022] [Indexed: 01/06/2023] Open
Abstract
In this article, we identified a novel epileptogenic variant (G307R) of the gene SLC6A1, which encodes the GABA transporter GAT-1. Our main goal was to investigate the pathogenic mechanisms of this variant, located near the neurotransmitter permeation pathway, and compare it with other variants located either in the permeation pathway or close to the lipid bilayer. The mutants G307R and A334P, close to the gates of the transporter, could be glycosylated with variable efficiency and reached the membrane, albeit inactive. Mutants located in the center of the permeation pathway (G297R) or close to the lipid bilayer (A128V, G550R) were retained in the endoplasmic reticulum. Applying an Elastic Network Model, to these and to other previously characterized variants, we found that G307R and A334P significantly perturb the structure and dynamics of the intracellular gate, which can explain their reduced activity, while for A228V and G362R, the reduced translocation to the membrane quantitatively accounts for the reduced activity. The addition of a chemical chaperone (4-phenylbutyric acid, PBA), which improves protein folding, increased the activity of GAT-1WT, as well as most of the assayed variants, including G307R, suggesting that PBA might also assist the conformational changes occurring during the alternative access transport cycle.
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11
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Verhoeven W, Zuijdam J, Scheick A, van Nieuwenhuijsen F, Zwemer AS, Pfundt R, Egger J. Myoclonic-Atonic Epilepsy Caused by a Novel de Novo Heterozygous Missense Variant in the SLC6A1 Gene: Brief Discussion of the Literature and Detailed Case Description of a Severely Intellectually Disabled Adult Male Patient. Int Med Case Rep J 2022; 15:753-759. [PMID: 36582431 PMCID: PMC9793742 DOI: 10.2147/imcrj.s390636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 12/10/2022] [Indexed: 12/25/2022] Open
Abstract
Introduction Diagnostic exome sequencing has yielded over the past decades a great number of molecular diagnoses for genetic disorders in which both intellectual disability and epilepsy are present. One of these syndromes is myoclonic-atonic epilepsy (MAE) that is caused by pathogenic variants in the SLC6A1 gene located at 3p25.3. The most relevant clinical characteristics are intellectual disability, several forms of mostly treatment-resistant epilepsy starting at young age, serious disinhibitory behavioural problems, language impairment, higher pain tolerance, and symptoms from the autism spectrum, all in the absence of any consistent dysmorphism or malformation. Methods After an overview of the literature, here, the developmental trajectory of a 55-year-old severely intellectually disabled male with therapy-resistant epilepsy and aggressive outburst is reported in detail, in whom no etiological diagnosis had been performed. Next to genetic, neurological, and neuropsychiatric examination, psychological assessment with validated instruments was performed. Results Exome sequencing and targeted analysis of the patient and both his parents demonstrated a de novo missense variant in the SLC6A1 gene which was never before described in the literature nor in control databases. The phenotypical presentation of the patient with treatment-resistant epilepsy, especially absences and myoclonic seizures, as well as sleep disturbances and autism, corresponds with a diagnosis of MAE. Discussion This case stresses that exome sequencing should be the first-tier diagnostic test for patients with unexplained neurodevelopmental disorders, regardless of their age, and that as yet the most suitable approach is the formation of an interdisciplinary team for treatment design and clinical management.
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Affiliation(s)
- Willem Verhoeven
- Department of Psychiatry, Erasmus University Medical Center, Rotterdam, the Netherlands,Centre for Consultation and Expertise, Utrecht, the Netherlands,Vincent van Gogh Centre of Excellence for Neuropsychiatry, Venray, the Netherlands,Correspondence: Willem Verhoeven, Centre of Excellence for Neuropsychiatry, Stationsweg 46, Venray, 5803 AC, the Netherlands, Tel +31651156556, Fax +31478584765, Email
| | - José Zuijdam
- Raphael Institute Breidablick, Centre for People with Intellectual Disabilities, Middenbeemster, the Netherlands
| | - Anneke Scheick
- Raphael Institute Breidablick, Centre for People with Intellectual Disabilities, Middenbeemster, the Netherlands
| | | | - Anne-Suus Zwemer
- ASVZ, Centre for People with Intellectual Disabilities, Sliedrecht, the Netherlands
| | - Rolph Pfundt
- Department of Human Genetics, Radboud University Medical Centre, Nijmegen, the Netherlands,Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Jos Egger
- Vincent van Gogh Centre of Excellence for Neuropsychiatry, Venray, the Netherlands,Department of Human Genetics, Radboud University Medical Centre, Nijmegen, the Netherlands,Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
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Angenoorth TJF, Maier J, Stankovic S, Bhat S, Sucic S, Freissmuth M, Sitte HH, Yang JW. Rescue of Misfolded Organic Cation Transporter 3 Variants. Cells 2022; 12:39. [PMID: 36611832 PMCID: PMC9818475 DOI: 10.3390/cells12010039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/13/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Organic cation transporters (OCTs) are membrane proteins that take up monoamines, cationic drugs and xenobiotics. We previously reported novel missense mutations of organic cation transporter 3 (OCT3, SLC22A3), some with drastically impacted transport capabilities compared to wildtype. For some variants, this was due to ER retention and subsequent degradation of the misfolded transporter. For other transporter families, it was previously shown that treatment of misfolded variants with pharmacological and chemical chaperones could restore transport function to a certain degree. To investigate two potentially ER-bound, misfolded variants (D340G and R348W), we employed confocal and biochemical analyses. In addition, radiotracer uptake assays were conducted to assess whether pre-treatment with chaperones could restore transporter function. We show that pre-treatment of cells with the chemical chaperone 4-PBA (4-phenyl butyric acid) leads to increased membrane expression of misfolded variants and is associated with increased transport capacity of D340G (8-fold) and R348W (1.5 times) compared to untreated variants. We herein present proof of principle that folding-deficient SLC22 transporter variants, in particular those of OCT3, are amenable to rescue by chaperones. These findings need to be extended to other SLC22 members with corroborated disease associations.
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Affiliation(s)
- Thomas J. F. Angenoorth
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
| | - Julian Maier
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
| | - Stevan Stankovic
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
| | - Shreyas Bhat
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
- Department of Physics, Université de Montréal, 1375 Avenue Thérèse-Lavoie-Roux, Montréal, QC H3T 1J4, Canada
- Department of Pharmacology and Physiology, Université de Montréal, 2960 Chemin de la Tour, Montréal, QC H3T 1J4, Canada
| | - Sonja Sucic
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
| | - Harald H. Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
| | - Jae-Won Yang
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
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13
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Dos Santos SR, Piergiorge RM, Rocha J, Abdala BB, Gonçalves AP, Pimentel MMG, Santos-Rebouças CB. A de novo YY1 missense variant expanding the Gabriele-de Vries syndrome phenotype and affecting X-chromosome inactivation. Metab Brain Dis 2022; 37:2431-2440. [PMID: 35829845 DOI: 10.1007/s11011-022-01024-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 06/04/2022] [Indexed: 11/30/2022]
Abstract
Yin and Yang 1 gene (YY1; MIM#600,013) is recognized as a dual transcriptional activating and repressing factor, RNA-binding protein, and 3D chromatin regulator, with multi roles in neurodevelopmental and maintenance pathways. YY1 haploinsufficiency caused either by heterozygous sequence variants or deletions involving the whole gene has been recently associated with Gabriele-de Vries syndrome (GADEVS), a rare congenital autosomal dominant condition, leading to intellectual disability (ID) and multiple physical/behavioural abnormalities. Herein, we describe clinical and molecular findings from a Brazilian female harbouring a de novo missense pathogenic variant in YY1 gene (NM_003403.5:c.1106A > G; p.Asn369Ser) found by whole exome sequencing with potential implications for protein structure and function. Undescribed or uncommon clinical features in this patient included non-febrile seizures, severe scoliosis, hearing impairment, and chorioretinitis. Further bioinformatics analyses using YY1-other protein interaction networks reinforced the involvement of YY1 interactors in such phenotypes, in exception of chorioretinitis. Moreover, X-chromosome inactivation (XCI) skewing was evidenced in the patient and attributed to the haploinsufficiency of YY1, which direct and indirectly interacts with numerous XCI key regulators. Besides expanding the mutational and phenotype spectrum of GADEVS, our results highlight the role of YY1 as an essential autosomal regulator of XCI epigenetic process.
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Affiliation(s)
- Suely Rodrigues Dos Santos
- Gaffrée and Guinle University Hospital, Federal University of Rio de Janeiro State, Rio de Janeiro, Brazil
| | - Rafael Mina Piergiorge
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Jady Rocha
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bianca Barbosa Abdala
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Andressa Pereira Gonçalves
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Márcia Mattos Gonçalves Pimentel
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Cíntia Barros Santos-Rebouças
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
- Departamento de Genética, Instituto de Biologia Roberto Alcantara Gomes, Universidade Do Estado Do Rio de Janeiro, Rua São Francisco Xavier, 524, PHLC - sala 501F, Maracanã 20550-013, Rio de Janeiro, RJ, Brazil.
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