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Singh A, Rizzi M, Seo SS, Osterweil EK. Syngap+/- CA1 Pyramidal Neurons Exhibit Upregulated Translation of Long MRNAs Associated with LTP. eNeuro 2025; 12:ENEURO.0086-25.2025. [PMID: 40295099 PMCID: PMC12091090 DOI: 10.1523/eneuro.0086-25.2025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2025] [Revised: 04/01/2025] [Accepted: 04/09/2025] [Indexed: 04/30/2025] Open
Abstract
In the Syngap+/- model of SYNGAP1-related intellectual disability (SRID), excessive neuronal protein synthesis is linked to deficits in synaptic plasticity. Here, we use Translating Ribosome Affinity Purification and RNA-seq (TRAP-seq) to identify mistranslating mRNAs in Syngap+/- CA1 pyramidal neurons that exhibit occluded long-term potentiation (LTP). We find the translation environment is significantly altered in a manner that is distinct from the Fmr1-/y model of fragile X syndrome (FXS), another monogenic model of autism and intellectual disability. The Syngap+/- translatome is enriched for regulators of DNA repair and mimics changes induced with chemical LTP (cLTP) in WT. This includes a striking upregulation in the translation of mRNAs with a longer-length (>2 kb) coding sequence (CDS). In contrast, long CDS transcripts are downregulated with induction of Gp1 metabotropic glutamate receptor-induced long-term depression (mGluR-LTD) in WT, and in the Fmr1-/y model that exhibits occluded mGluR-LTD. Together, our results show the Syngap+/- and Fmr1-/y models mimic the translation environments of LTP and LTD, respectively, consistent with the saturation of plasticity states in each model. Moreover, we show that translation of >2 kb mRNAs is a defining feature of LTP that is oppositely regulated during LTD, revealing a novel mRNA signature of plasticity.
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Affiliation(s)
- Aditi Singh
- Rosamund Stone Zander Translational Neuroscience Center, F. M. Kirby Center, Department of Neurology, Harvard Medical School, Boston Children's Hospital, Boston, Massachusetts 02115
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
| | - Manuela Rizzi
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
| | - Sang S Seo
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
| | - Emily K Osterweil
- Rosamund Stone Zander Translational Neuroscience Center, F. M. Kirby Center, Department of Neurology, Harvard Medical School, Boston Children's Hospital, Boston, Massachusetts 02115
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
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2
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McKinney WS, Schmitt LM, De Stefano LA, Ethridge L, Norris JE, Horn PS, Dauterman S, Rosselot H, Pedapati EV, Reisinger DL, Dominick KC, Shaffer RC, Chin D, Friedman NR, Hong M, Sweeney JA, Erickson C. Results from a Double-Blind, Randomized, Placebo-Controlled, Single-Dose, Crossover Trial of Lovastatin or Minocycline in Fragile X Syndrome. J Child Adolesc Psychopharmacol 2025; 35:211-221. [PMID: 39651602 DOI: 10.1089/cap.2024.0103] [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] [Indexed: 12/11/2024]
Abstract
Introduction: Treatment studies in FMR1 knockout rodent models have found that minocycline and lovastatin each improve synaptic, neurological, and behavioral functioning, and open-label chronic dosing studies in human patients with fragile X syndrome (FXS) have demonstrated modest clinical improvements. Findings from blinded studies are mixed, and there is a limited understanding of electrophysiological target engagement that would facilitate cross-species translational studies. Smaller-scale, acute (e.g., single-dose) drug studies may speed treatment identification by detecting subtle electrophysiological and behavioral changes. Materials and Methods: Twenty-nine participants with FXS (31% female) ages 15-45 years completed a randomized, double-blind, crossover study in which they received a single oral dose of 40 mg of lovastatin, 270 mg of minocycline, or placebo, with a 2-week washout period between dosing visits. Participants completed a comprehensive neuropsychological battery and three EEG paradigms (resting state; auditory chirp; auditory habituation) before and 4 hours after dosing. Results: No serious adverse events were reported, and both drugs were well-tolerated. Compared with placebo, there were no overall treatment effects for any outcomes, including EEG, but several modest drug responses varied as a function of sex and age. Lovastatin treatment was associated with improved spatial awareness in older participants and females compared with minocycline and placebo. Discussion: We show that single-dose drug studies are highly feasible in FXS and that patients with FXS can complete a range of EEG and behavioral tasks, many of which have been shown to be reliable and may therefore be sensitive to subtle drug target engagement. Conclusions: Acute single doses of lovastatin or minocycline did not lead to changes in electrophysiological or performance-based measures. This may be due to the limited effects of these drugs in human patients or limited acute effects relative to chronic dosing. However, the study design was further validated for use in neurodevelopmental populations.
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Affiliation(s)
- Walker S McKinney
- Department of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Lauren M Schmitt
- Department of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Lisa A De Stefano
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Lauren Ethridge
- Department of Psychology, University of Oklahoma, Norman, Oklahoma, USA
- Department of Pediatrics, Section of Developmental and Behavioral Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Jordan E Norris
- Department of Psychology, University of Oklahoma, Norman, Oklahoma, USA
| | - Paul S Horn
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Shelby Dauterman
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | | | - Ernest V Pedapati
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Debra L Reisinger
- Department of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Kelli C Dominick
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Rebecca C Shaffer
- Department of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Danielle Chin
- The Heidt Center of Excellence, Cincinnati, Ohio, USA
| | - Nicole R Friedman
- Department of Psychology, University of Alabama, Tuscaloosa, Alabama, USA
| | - Michael Hong
- Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - John A Sweeney
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Craig Erickson
- Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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3
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Guan C, Otchere A, Laskovs M, Papatheodorou I, Slack C. Genetic and Pharmacological Inhibition of Metabotropic Glutamate Receptor Signalling Extends Lifespan in Drosophila. Aging Cell 2025; 24:e14500. [PMID: 39943697 PMCID: PMC12073928 DOI: 10.1111/acel.14500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2024] [Revised: 01/10/2025] [Accepted: 01/14/2025] [Indexed: 05/15/2025] Open
Abstract
Invertebrate models have been instrumental in advancing our understanding of the molecular mechanisms of ageing. The isolation of single gene mutations that both extend lifespan and improve age-related health have identified potential targets for therapeutic intervention to alleviate age-related morbidity. Here, we find that genetic loss of function of the G protein-coupled metabotropic glutamate receptor (DmGluRA) in Drosophila extends the lifespan of female flies. This longevity phenotype was accompanied by lower basal levels of oxidative stress and improved stress tolerance, and differences in early-life behavioural markers. Gene expression changes in DmGluRA mutants identified reduced ribosome biogenesis, a hallmark of longevity, as a key process altered in these animals. We further show that the pro-longevity effects of reduced DmGluRA signalling are dependent on the fly homologue of Fragile X Mental Retardation Protein (FMRP), an important regulator of ribosomal protein translation. Importantly, we can recapitulate lifespan extension using a specific pharmacological inhibitor of mGluR activity. Hence, our study identifies metabotropic glutamate receptors as potential targets for age-related therapeutics.
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Affiliation(s)
- Cui Guan
- College of Health and Life SciencesAston UniversityBirminghamUK
- School of Life SciencesWarwick UniversityCoventryUK
| | - Abigail Otchere
- College of Health and Life SciencesAston UniversityBirminghamUK
| | - Mihails Laskovs
- College of Health and Life SciencesAston UniversityBirminghamUK
- School of Life SciencesWarwick UniversityCoventryUK
| | | | - Cathy Slack
- College of Health and Life SciencesAston UniversityBirminghamUK
- School of Life SciencesWarwick UniversityCoventryUK
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Winarni TI, Aishworiya R, Culpepper H, Zafarullah M, Mendoza G, Wilaisakditipakorn TJ, Likhitweerawong N, Law J, Hagerman R, Tassone F. In Utero Alcohol and Unsuitable Home Environmental Exposure Combined with FMR1 Full Mutation Allele Cause Severe Fragile X Syndrome Phenotypes. Int J Mol Sci 2025; 26:2840. [PMID: 40243429 PMCID: PMC11988866 DOI: 10.3390/ijms26072840] [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: 01/30/2025] [Revised: 03/11/2025] [Accepted: 03/13/2025] [Indexed: 04/18/2025] Open
Abstract
We investigated the molecular and clinical profile of five boys carrying the fragile X messenger ribonucleoprotein 1 (FMR1) mutation and who suffered from the effects of prenatal alcohol exposure. Fragile X syndrome (FXS) testing was performed using PCR and Southern Blot analysis, and fragile X messenger ribonucleoprotein protein (FMRP) expression levels were measured by Western blot analysis. Clinical evaluation included cognitive functions, adaptive skills, autism phenotype, and severity of behavior measures. Fetal Alcohol Spectrum Disorder (FASD) was also assessed. Five adopted male siblings were investigated, four of which (cases 1, 2, 3, and 4) were diagnosed with FXS, FASD, and ASD, and one, the fraternal triplet (case 5), was diagnosed with FASD and ASD and no FXS. The molecular profile of case 1 and 2 showed the presence of a hypermethylated full mutation (FM) and the resulting absence of FMRP. Cases 3 and 4 (identical twins) were FM-size mosaics (for the presence of an FM and a deleted allele), resulting in 16% and 50% FMRP expression levels, respectively. FMRP expression level was normal in case 5 (fraternal twin). Severe behavioral problems were observed in all cases, including aggression, tantrum, self-harming, anxiety, and defiant behavior, due to different mutations of the FMR1 gene, in addition to biological exposure, home environmental factors, and potentially to additional background gene effects.
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Affiliation(s)
- Tri Indah Winarni
- Center for Biomedical Research (CEBIOR), Faculty of Medicine, Universitas Diponegoro, Semarang 50275, Central Java, Indonesia;
| | - Ramkumar Aishworiya
- Khoo Teck Puat-National University Children’s Medical Institute, National University Health System, Singapore 119074, Singapore;
- Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Hannah Culpepper
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA; (H.C.); (M.Z.); (G.M.)
| | - Marwa Zafarullah
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA; (H.C.); (M.Z.); (G.M.)
| | - Guadalupe Mendoza
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA; (H.C.); (M.Z.); (G.M.)
| | - Tanaporn Jasmine Wilaisakditipakorn
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA 95817, USA; (T.J.W.); (J.L.); (R.H.)
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA;
| | - Narueporn Likhitweerawong
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA;
- Department of Pediatrics, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Julie Law
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA 95817, USA; (T.J.W.); (J.L.); (R.H.)
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA;
| | - Randi Hagerman
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA 95817, USA; (T.J.W.); (J.L.); (R.H.)
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA;
| | - Flora Tassone
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA; (H.C.); (M.Z.); (G.M.)
- MIND Institute, University of California Davis Medical Center, Sacramento, CA 95817, USA;
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5
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Lee YT, Kang JW, Heo JI, Seo TW, Yoo SJ. cIAP2 supports the cell growth-promoting activity of FMR1 in gastric cancer via CARD-RING domains. Biochem Biophys Res Commun 2025; 743:151189. [PMID: 39693941 DOI: 10.1016/j.bbrc.2024.151189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2024] [Revised: 12/10/2024] [Accepted: 12/13/2024] [Indexed: 12/20/2024]
Abstract
Fragile X Mental Retardation Protein 1 (FMR1) is a translational repressor crucial for regulating genes in the central nervous system. While a lack of FMR1 expression causes Fragile X Syndrome (FXS), its overexpression is implicated in various cancers, necessitating tight regulation of FMR1 protein levels for normal cell physiology. In this study, we report that FMR1 is upregulated in gastric cancer patients. Reducing FMR1 expression decreased cell growth in gastric cancer cell lines. The Smac Mimetic LCL161 reduced both FMR1 and cellular inhibitor of apoptosis protein 2 (cIAP2) levels. Suppressing cIAP2, but not cIAP1, led to decreased FMR1, while cIAP2 overexpression increased FMR1 in gastric cancer cells. We observed that cIAP2 is also upregulated in gastric cancer patients, with FMR1 and cIAP2 levels positively correlated in both gastric and colorectal cancers. Notably, cIAP2 binds FMR1 via its CARD domain, unlike most cIAP2 targets that bind the BIR domain. Furthermore, cIAP2 ubiquitinates FMR1 through its CARD-RING domains, stabilizing the protein without proteasomal degradation. FMR1, modulated by cIAP2, promotes gastric cancer cell growth. Collectively, our findings highlight FMR1's growth-promoting role in gastric cancer and reveal a novel function of cIAP2 in stabilizing FMR1 as an E3 ligase. These results suggest targeting cIAP2 could be an effective strategy for treating gastric cancer by downregulating both cIAP2 and FMR1.
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Affiliation(s)
- Yui Taek Lee
- Department of Biology, Kyung Hee University, Seoul, 02447, South Korea.
| | - Ji Woo Kang
- Department of Biology, Kyung Hee University, Seoul, 02447, South Korea.
| | - Jeong In Heo
- Department of Biology, Kyung Hee University, Seoul, 02447, South Korea.
| | - Tae Woong Seo
- Department of Biology, Kyung Hee University, Seoul, 02447, South Korea
| | - Soon Ji Yoo
- Department of Biology, Kyung Hee University, Seoul, 02447, South Korea.
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6
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Gillett DA, Tigro H, Wang Y, Suo Z. FMR1 Disorders: Basics of Biology and Therapeutics in Development. Cells 2024; 13:2100. [PMID: 39768191 PMCID: PMC11674747 DOI: 10.3390/cells13242100] [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: 10/24/2024] [Revised: 12/04/2024] [Accepted: 12/13/2024] [Indexed: 01/11/2025] Open
Abstract
Fragile X Syndrome (FXS) presents with a constellation of phenotypes, including trouble regulating emotion and aggressive behaviors, disordered sleep, intellectual impairments, and atypical physical development. Genetic study of the X chromosome revealed that substantial repeat expansion of the 5' end of the gene fragile X messenger ribonucleoprotein 1 (FMR1) promoted DNA methylation and, consequently, silenced expression of FMR1. Further analysis proved that shorter repeat expansions in FMR1 also manifested in disease at later stages in life. Treatment and therapy options do exist, but they only manage symptoms. Up to now, no cure for FMR1 disorders exists. In this review, we aim to provide an overview of FMR1 biology and the latest research focused on developing therapeutic interventions that can potentially prevent and/or reverse FXS.
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Affiliation(s)
| | | | | | - Zucai Suo
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA
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7
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Uneri A, McArdle CJ, Deng Z, Barth SH, Keene D, Craft S, Raab-Graham KF. DJ-1-mediated repression of the RNA-binding protein FMRP is predicted to impact known Alzheimer's disease-related protein networks. J Alzheimers Dis 2024; 102:763-777. [PMID: 39610285 DOI: 10.1177/13872877241291175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2024]
Abstract
BACKGROUND RNA-binding proteins (RBPs) modulate the synaptic proteome and are instrumental in maintaining synaptic homeostasis. Moreover, aberrant expression of an RBP in a disease state would have deleterious downstream effects on synaptic function. While many underlying mechanisms of synaptic dysfunction in Alzheimer's disease (AD) have been proposed, the contribution of RBPs has been relatively unexplored. OBJECTIVE To investigate alterations in RBP-messenger RNA (mRNA) interactions in AD, and its overall impact on the disease-related proteome. METHODS We first utilized RNA-immunoprecipitation to investigate interactions between RBP, DJ-1 (Parkinson's Disease protein 7) and target mRNAs in controls and AD. Surface Sensing of Translation - Proximity Ligation Assay (SUnSET-PLA) and western blotting additionally quantified alterations in mRNA translation and protein expression of DJ-1 targets. Finally, we utilized an unbiased bioinformatic approach that connects AD-related pathways to two RBPs, DJ-1 and FMRP (Fragile X messenger ribonucleoprotein 1). RESULTS We find that oligomeric DJ-1 in AD donor synapses were less dynamic in their ability to bind and unbind mRNA compared to synapses from cognitively unimpaired, neuropathologically-verified controls. Furthermore, we find that DJ-1 associates with the mRNA coding for FMRP, Fmr1, leading to its reduced synaptic expression in AD. Through the construction of protein-protein interaction networks, aberrant expression of DJ-1 and FMRP are predicted to lead to the upregulation of key AD-related pathways, such as thyroid hormone stimulating pathway, autophagy, and ubiquitin mediated proteolysis. CONCLUSIONS DJ-1 and FMRP are novel targets that may restore established neurobiological mechanisms underlying AD.
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Affiliation(s)
- Ayse Uneri
- Department of Translational Neuroscience, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA
| | - Colin J McArdle
- Department of Translational Neuroscience, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA
| | - Zhiyong Deng
- Department of Translational Neuroscience, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA
| | - Samuel H Barth
- Department of Translational Neuroscience, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA
| | - Dirk Keene
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
- Department of Gerontology and Geriatric Medicine, Wake Forest Alzheimer's Disease Research Center, Winston-Salem, NC, USA
| | - Suzanne Craft
- Department of Gerontology and Geriatric Medicine, Wake Forest Alzheimer's Disease Research Center, Winston-Salem, NC, USA
| | - Kimberly F Raab-Graham
- Department of Translational Neuroscience, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA
- Department of Gerontology and Geriatric Medicine, Wake Forest Alzheimer's Disease Research Center, Winston-Salem, NC, USA
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8
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Morin-Parent F, Champigny C, Côté S, Mohamad T, Hasani SA, Çaku A, Corbin F, Lepage JF. Neurophysiological effects of a combined treatment of lovastatin and minocycline in patients with fragile X syndrome: Ancillary results of the LOVAMIX randomized clinical trial. Autism Res 2024; 17:1944-1956. [PMID: 39248107 DOI: 10.1002/aur.3222] [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: 06/04/2024] [Accepted: 08/09/2024] [Indexed: 09/10/2024]
Abstract
Fragile X syndrome (FXS) is the primary hereditary cause of intellectual disability and autism spectrum disorder. It is characterized by exacerbated neuronal excitability, and its correction is considered an objective measure of treatment response in animal models, a marker albeit rarely used in clinical trials. Here, we used an extensive transcranial magnetic stimulation (TMS) battery to assess the neurophysiological effects of a therapy combining two disease-modifying drugs, lovastatin (40 mg) and minocycline (100 mg), administered alone for 8 weeks and in combination for 12 weeks, in 19 patients (mean age of 23.58 ± 1.51) with FXS taking part in the LOVAmix trial. The TMS battery, which included the resting motor threshold, short-interval intracortical inhibition, long-interval intracortical inhibition, corticospinal silent period, and intracortical facilitation, was completed at baseline after 8 weeks of monotherapy (visit 2 of the clinical trial) and after 12 weeks of dual therapy (visit 4 of the clinical trial). Repeated measure ANOVAs were performed between baseline and visit 2 (monotherapy) and visit 3 (dual therapy) with interactions for which monotherapy the participants received when they began the clinical trial. Results showed that dual therapy was associated with reduced cortical excitability after 20 weeks. This was reflected by a significant increase in the resting-motor threshold after dual therapy compared to baseline. There was a tendency for enhanced short-intracortical inhibition, a marker of GABAa-mediated inhibition after 8 weeks of monotherapy compared to baseline. Together, these results suggest that a combined therapy of minocycline and lovastatin might act on the core neurophysiopathology of FXS. This trial was registered at clinicaltrials.gov (NCT02680379).
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Affiliation(s)
- Florence Morin-Parent
- Department of Pediatrics, Faculty of Medicine and Health Sciences, Sherbrooke University, Sherbrooke, Canada
- Sherbrooke University Hospital Research Center, Sherbrooke, Canada
| | - Camille Champigny
- Sherbrooke University Hospital Research Center, Sherbrooke, Canada
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences Sherbrooke University, Sherbrooke, Canada
| | - Samantha Côté
- Department of Pediatrics, Faculty of Medicine and Health Sciences, Sherbrooke University, Sherbrooke, Canada
| | - Teddy Mohamad
- Department of Pediatrics, Faculty of Medicine and Health Sciences, Sherbrooke University, Sherbrooke, Canada
- Sherbrooke University Hospital Research Center, Sherbrooke, Canada
| | - Seyede Anis Hasani
- Department of Pediatrics, Faculty of Medicine and Health Sciences, Sherbrooke University, Sherbrooke, Canada
- Sherbrooke University Hospital Research Center, Sherbrooke, Canada
| | - Artuela Çaku
- Sherbrooke University Hospital Research Center, Sherbrooke, Canada
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences Sherbrooke University, Sherbrooke, Canada
| | - François Corbin
- Sherbrooke University Hospital Research Center, Sherbrooke, Canada
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences Sherbrooke University, Sherbrooke, Canada
| | - Jean-François Lepage
- Department of Pediatrics, Faculty of Medicine and Health Sciences, Sherbrooke University, Sherbrooke, Canada
- Sherbrooke University Hospital Research Center, Sherbrooke, Canada
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Messaoudi S, Allam A, Stoufflet J, Paillard T, Le Ven A, Fouquet C, Doulazmi M, Trembleau A, Caille I. FMRP regulates postnatal neuronal migration via MAP1B. eLife 2024; 12:RP88782. [PMID: 38757694 PMCID: PMC11101172 DOI: 10.7554/elife.88782] [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] [Indexed: 05/18/2024] Open
Abstract
The fragile X syndrome (FXS) represents the most prevalent form of inherited intellectual disability and is the first monogenic cause of autism spectrum disorder. FXS results from the absence of the RNA-binding protein FMRP (fragile X messenger ribonucleoprotein). Neuronal migration is an essential step of brain development allowing displacement of neurons from their germinal niches to their final integration site. The precise role of FMRP in neuronal migration remains largely unexplored. Using live imaging of postnatal rostral migratory stream (RMS) neurons in Fmr1-null mice, we observed that the absence of FMRP leads to delayed neuronal migration and altered trajectory, associated with defects of centrosomal movement. RNA-interference-induced knockdown of Fmr1 shows that these migratory defects are cell-autonomous. Notably, the primary Fmrp mRNA target implicated in these migratory defects is microtubule-associated protein 1B (MAP1B). Knocking down MAP1B expression effectively rescued most of the observed migratory defects. Finally, we elucidate the molecular mechanisms at play by demonstrating that the absence of FMRP induces defects in the cage of microtubules surrounding the nucleus of migrating neurons, which is rescued by MAP1B knockdown. Our findings reveal a novel neurodevelopmental role for FMRP in collaboration with MAP1B, jointly orchestrating neuronal migration by influencing the microtubular cytoskeleton.
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Affiliation(s)
- Salima Messaoudi
- Sorbonne Université, CNRS UMR8246, Inserm U1130, Institut de Biologie Paris Seine (IBPS), Neuroscience Paris Seine (NPS)ParisFrance
| | - Ada Allam
- Sorbonne Université, CNRS UMR8246, Inserm U1130, Institut de Biologie Paris Seine (IBPS), Neuroscience Paris Seine (NPS)ParisFrance
| | - Julie Stoufflet
- Sorbonne Université, CNRS UMR8246, Inserm U1130, Institut de Biologie Paris Seine (IBPS), Neuroscience Paris Seine (NPS)ParisFrance
- Laboratory of Molecular Regulation of Neurogenesis, GIGA-Stem Cells and GIGA-Neurosciences, University of Liège, CHU Sart TilmanLiègeBelgium
| | - Theo Paillard
- Sorbonne Université, CNRS UMR8246, Inserm U1130, Institut de Biologie Paris Seine (IBPS), Neuroscience Paris Seine (NPS)ParisFrance
| | - Anaïs Le Ven
- Sorbonne Université, CNRS UMR8246, Inserm U1130, Institut de Biologie Paris Seine (IBPS), Neuroscience Paris Seine (NPS)ParisFrance
- Institut CurieParisFrance
| | - Coralie Fouquet
- Sorbonne Université, CNRS UMR8246, Inserm U1130, Institut de Biologie Paris Seine (IBPS), Neuroscience Paris Seine (NPS)ParisFrance
| | - Mohamed Doulazmi
- Sorbonne Université, CNRS UMR8246, Inserm U1130, Institut de Biologie Paris Seine (IBPS), Neuroscience Paris Seine (NPS)ParisFrance
| | - Alain Trembleau
- Sorbonne Université, CNRS UMR8246, Inserm U1130, Institut de Biologie Paris Seine (IBPS), Neuroscience Paris Seine (NPS)ParisFrance
| | - Isabelle Caille
- Sorbonne Université, CNRS UMR8246, Inserm U1130, Institut de Biologie Paris Seine (IBPS), Neuroscience Paris Seine (NPS)ParisFrance
- Université de ParisParisFrance
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Di Liegro CM, Schiera G, Schirò G, Di Liegro I. Role of Post-Transcriptional Regulation in Learning and Memory in Mammals. Genes (Basel) 2024; 15:337. [PMID: 38540396 PMCID: PMC10970538 DOI: 10.3390/genes15030337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 02/27/2024] [Accepted: 03/01/2024] [Indexed: 06/14/2024] Open
Abstract
After many decades, during which most molecular studies on the regulation of gene expression focused on transcriptional events, it was realized that post-transcriptional control was equally important in order to determine where and when specific proteins were to be synthesized. Translational regulation is of the most importance in the brain, where all the steps of mRNA maturation, transport to different regions of the cells and actual expression, in response to specific signals, constitute the molecular basis for neuronal plasticity and, as a consequence, for structural stabilization/modification of synapses; notably, these latter events are fundamental for the highest brain functions, such as learning and memory, and are characterized by long-term potentiation (LTP) of specific synapses. Here, we will discuss the molecular bases of these fundamental events by considering both the role of RNA-binding proteins (RBPs) and the effects of non-coding RNAs involved in controlling splicing, editing, stability and translation of mRNAs. Importantly, it has also been found that dysregulation of mRNA metabolism/localization is involved in many pathological conditions, arising either during brain development or in the adult nervous system.
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Affiliation(s)
- Carlo Maria Di Liegro
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, 90128 Palermo, Italy; (C.M.D.L.); (G.S.)
| | - Gabriella Schiera
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, 90128 Palermo, Italy; (C.M.D.L.); (G.S.)
| | - Giuseppe Schirò
- Department of Biomedicine, Neurosciences and Advanced Diagnostics, University of Palermo, 90127 Palermo, Italy;
- Neurology and Multiple Sclerosis Center, Unità Operativa Complessa (UOC), Foundation Institute “G. Giglio”, 90015 Cefalù, Italy
| | - Italia Di Liegro
- Department of Biomedicine, Neurosciences and Advanced Diagnostics, University of Palermo, 90127 Palermo, Italy;
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11
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Zhao S, Jiang X, Han L, Jiang Y, Wang Y, Meng J, Zhu X, Zhang X, Luo H, Zhang YW. Tau reduction attenuates autism-like features in Fmr1 knockout mice. Mol Autism 2023; 14:42. [PMID: 37936174 PMCID: PMC10629153 DOI: 10.1186/s13229-023-00574-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/30/2023] [Indexed: 11/09/2023] Open
Abstract
BACKGROUND Fragile X syndrome (FXS) is a leading cause of autism spectrum disorder (ASD) and resulted from a loss of the FMR1-encoded fragile X messenger ribonucleoprotein 1 (FMRP) protein due to large CGG repeat expansions in the promoter region of the FMR1 gene. The microtubule-associated protein Tau is a promising target for Tauopathic diseases and our preliminary study found that Tau protein levels were increased in the brain of Fmr1 knockout (KO) mice, a model of FXS. However, whether Tau reduction can prevent autism-like features in Fmr1 KO mice and become a novel strategy for FXS treatment remain unknown. METHODS Tau was genetically reduced in Fmr1 KO mice through crossing Fmr1± female mice with Mapt± male mice. The male offspring with different genotypes were subjected to various autism-related behavioral tests, RNA sequencing, and biochemical analysis. Fmr1 KO male mice were treated with Tau-targeting antisense oligonucleotide (ASO) and then subjected to behavioral tests and biochemical analysis. RESULTS Tau expression was increased in the cortex of Fmr1 KO mice. Genetically reducing Tau prevented social defects, stereotyped and repetitive behavior, and spine abnormality in Fmr1 KO mice. Tau reduction also reversed increased periodic activity and partially rescued Per1 expression reduction in Fmr1 KO mice. Moreover, Tau reduction reversed compromised P38/MAPK signaling in Fmr1 KO mice. Finally, Tau-targeting ASO also effectively alleviated autism-like phenotypes and promoted P38/MAPK signaling in Fmr1 KO mice. LIMITATIONS Our study is limited to male mice, in agreement with the higher incidence of FXS in males than females. Whether Tau reduction also exerts protection in females deserves further scrutiny. Moreover, although Tau reduction rescues impaired P38/MAPK signaling in Fmr1 KO mice, whether this is the responsible molecular mechanism requires further determination. CONCLUSION Our data indicate that Tau reduction prevents autism-like phenotypes in Fmr1 KO mice. Tau may become a new target for FXS treatment.
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Affiliation(s)
- Shanshan Zhao
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Xiangyu Jiang
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Linkun Han
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Yiru Jiang
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Yong Wang
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Jian Meng
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Xiang Zhu
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Xian Zhang
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Hong Luo
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Yun-Wu Zhang
- Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, and Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China.
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12
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Winden KD, Pham TT, Teaney NA, Ruiz J, Chen R, Chen C, Sahin M. Increased degradation of FMRP contributes to neuronal hyperexcitability in tuberous sclerosis complex. Cell Rep 2023; 42:112838. [PMID: 37494191 PMCID: PMC10529098 DOI: 10.1016/j.celrep.2023.112838] [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: 12/16/2022] [Revised: 05/12/2023] [Accepted: 07/05/2023] [Indexed: 07/28/2023] Open
Abstract
Autism spectrum disorder (ASD) is a highly prevalent neurodevelopmental disorder, but new therapies have been impeded by a lack of understanding of the pathological mechanisms. Tuberous sclerosis complex (TSC) and fragile X syndrome are associated with alterations in the mechanistic target of rapamycin (mTOR) and fragile X messenger ribonucleoprotein 1 (FMRP), which have been implicated in the development of ASD. Previously, we observed that transcripts associated with FMRP were down-regulated in TSC2-deficient neurons. In this study, we find that FMRP turnover is dysregulated in TSC2-deficient rodent primary neurons and human induced pluripotent stem cell (iPSC)-derived neurons and is dependent on the E3 ubiquitin ligase anaphase-promoting complex. We also demonstrate that overexpression of FMRP can partially rescue hyperexcitability in TSC2-deficient iPSC-derived neurons. These data indicate that FMRP dysregulation represents an important pathological mechanism in the development of abnormal neuronal activity in TSC and illustrate a molecular convergence between these two neurogenetic disorders.
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Affiliation(s)
- Kellen D Winden
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Truc T Pham
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Nicole A Teaney
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Juan Ruiz
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Ryan Chen
- Human Neuron Core, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Cidi Chen
- Human Neuron Core, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Mustafa Sahin
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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13
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Longo F, Aryal S, Anastasiades PG, Maltese M, Baimel C, Albanese F, Tabor J, Zhu JD, Oliveira MM, Gastaldo D, Bagni C, Santini E, Tritsch NX, Carter AG, Klann E. Cell-type-specific disruption of cortico-striatal circuitry drives repetitive patterns of behavior in fragile X syndrome model mice. Cell Rep 2023; 42:112901. [PMID: 37505982 PMCID: PMC10552611 DOI: 10.1016/j.celrep.2023.112901] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 05/18/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Individuals with fragile X syndrome (FXS) are frequently diagnosed with autism spectrum disorder (ASD), including increased risk for restricted and repetitive behaviors (RRBs). Consistent with observations in humans, FXS model mice display distinct RRBs and hyperactivity that are consistent with dysfunctional cortico-striatal circuits, an area relatively unexplored in FXS. Using a multidisciplinary approach, we dissect the contribution of two populations of striatal medium spiny neurons (SPNs) in the expression of RRBs in FXS model mice. Here, we report that dysregulated protein synthesis at cortico-striatal synapses is a molecular culprit of the synaptic and ASD-associated motor phenotypes displayed by FXS model mice. Cell-type-specific translational profiling of the FXS mouse striatum reveals differentially translated mRNAs, providing critical information concerning potential therapeutic targets. Our findings uncover a cell-type-specific impact of the loss of fragile X messenger ribonucleoprotein (FMRP) on translation and the sequence of neuronal events in the striatum that drive RRBs in FXS.
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Affiliation(s)
- Francesco Longo
- Center for Neural Science, New York University, New York, NY 10003, USA; Institute for Neuroscience and Physiology, University of Gothenburg, 40530 Gothenburg, Sweden; Sackler Institute of Graduate Biomedical Sciences, NYU School of Medicine, New York, NY 10016, USA
| | - Sameer Aryal
- Center for Neural Science, New York University, New York, NY 10003, USA; NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, NY 10016, USA
| | | | - Marta Maltese
- Fresco Institute for Parkinson's and Movement Disorders, New York University Langone Health, New York, NY 10016, USA; Department of Fundamental Neurosciences, University of Lausanne, 1005 Lausanne, Switzerland
| | - Corey Baimel
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - Federica Albanese
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - Joanna Tabor
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - Jeffrey D Zhu
- Center for Neural Science, New York University, New York, NY 10003, USA
| | | | - Denise Gastaldo
- Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 1005 Rome, Italy
| | - Claudia Bagni
- Department of Biomedicine and Prevention, University of Rome "Tor Vergata," 1005 Rome, Italy
| | - Emanuela Santini
- Center for Neural Science, New York University, New York, NY 10003, USA; Department of Neuroscience, Biomedicum, Karolinska Institute, 171 77 Stockholm, Sweden
| | - Nicolas X Tritsch
- NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, NY 10016, USA; Fresco Institute for Parkinson's and Movement Disorders, New York University Langone Health, New York, NY 10016, USA
| | - Adam G Carter
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY 10003, USA; NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, NY 10016, USA.
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14
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Jong YJI, Izumi Y, Harmon SK, Zorumski CF, ÓMalley KL. Striatal mGlu 5-mediated synaptic plasticity is independently regulated by location-specific receptor pools and divergent signaling pathways. J Biol Chem 2023; 299:104949. [PMID: 37354970 PMCID: PMC10388212 DOI: 10.1016/j.jbc.2023.104949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 06/26/2023] Open
Abstract
Metabotropic glutamate receptor 5 (mGlu5) is widely expressed throughout the central nervous system and is involved in neuronal function, synaptic transmission, and a number of neuropsychiatric disorders such as depression, anxiety, and autism. Recent work from this lab showed that mGlu5 is one of a growing number of G protein-coupled receptors that can signal from intracellular membranes where it drives unique signaling pathways, including upregulation of extracellular signal-regulated kinase (ERK1/2), ETS transcription factor Elk-1, and activity-regulated cytoskeleton-associated protein (Arc). To determine the roles of cell surface mGlu5 as well as the intracellular receptor in a well-known mGlu5 synaptic plasticity model such as long-term depression, we used pharmacological isolation and genetic and physiological approaches to analyze spatially restricted pools of mGlu5 in striatal cultures and slice preparations. Here we show that both intracellular and cell surface receptors activate the phosphatidylinositol-3-kinase-protein kinase B-mammalian target of rapamycin (PI3K/AKT/mTOR) pathway, whereas only intracellular mGlu5 activates protein phosphatase 2 and leads to fragile X mental retardation protein degradation and de novo protein synthesis followed by a protein synthesis-dependent increase in Arc and post-synaptic density protein 95. However, both cell surface and intracellular mGlu5 activation lead to α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor GluA2 internalization and chemically induced long-term depression albeit via different signaling mechanisms. These data underscore the importance of intracellular mGlu5 in the cascade of events associated with sustained synaptic transmission in the striatum.
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Affiliation(s)
- Yuh-Jiin I Jong
- Department of Neuroscience, Washington University School of Medicine, St Louis, Missouri, USA
| | - Yukitoshi Izumi
- Department of Psychiatry, Washington University School of Medicine, St Louis, Missouri, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St Louis, Missouri, USA
| | - Steven K Harmon
- Department of Neuroscience, Washington University School of Medicine, St Louis, Missouri, USA
| | - Charles F Zorumski
- Department of Neuroscience, Washington University School of Medicine, St Louis, Missouri, USA; Department of Psychiatry, Washington University School of Medicine, St Louis, Missouri, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St Louis, Missouri, USA
| | - Karen L ÓMalley
- Department of Neuroscience, Washington University School of Medicine, St Louis, Missouri, USA.
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15
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Fodder K, Murthy M, Rizzu P, Toomey CE, Hasan R, Humphrey J, Raj T, Lunnon K, Mill J, Heutink P, Lashley T, Bettencourt C. Brain DNA methylomic analysis of frontotemporal lobar degeneration reveals OTUD4 in shared dysregulated signatures across pathological subtypes. Acta Neuropathol 2023; 146:77-95. [PMID: 37149835 PMCID: PMC10261190 DOI: 10.1007/s00401-023-02583-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 04/28/2023] [Accepted: 04/28/2023] [Indexed: 05/08/2023]
Abstract
Frontotemporal lobar degeneration (FTLD) is an umbrella term describing the neuropathology of a clinically, genetically and pathologically heterogeneous group of diseases, including frontotemporal dementia (FTD) and progressive supranuclear palsy (PSP). Among the major FTLD pathological subgroups, FTLD with TDP-43 positive inclusions (FTLD-TDP) and FTLD with tau-positive inclusions (FTLD-tau) are the most common, representing about 90% of the cases. Although alterations in DNA methylation have been consistently associated with neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease, little is known for FTLD and its heterogeneous subgroups and subtypes. The main goal of this study was to investigate DNA methylation variation in FTLD-TDP and FTLD-tau. We used frontal cortex genome-wide DNA methylation profiles from three FTLD cohorts (142 FTLD cases and 92 controls), generated using the Illumina 450K or EPIC microarrays. We performed epigenome-wide association studies (EWAS) for each cohort followed by meta-analysis to identify shared differentially methylated loci across FTLD subgroups/subtypes. In addition, we used weighted gene correlation network analysis to identify co-methylation signatures associated with FTLD and other disease-related traits. Wherever possible, we also incorporated relevant gene/protein expression data. After accounting for a conservative Bonferroni multiple testing correction, the EWAS meta-analysis revealed two differentially methylated loci in FTLD, one annotated to OTUD4 (5'UTR-shore) and the other to NFATC1 (gene body-island). Of these loci, OTUD4 showed consistent upregulation of mRNA and protein expression in FTLD. In addition, in the three independent co-methylation networks, OTUD4-containing modules were enriched for EWAS meta-analysis top loci and were strongly associated with the FTLD status. These co-methylation modules were enriched for genes implicated in the ubiquitin system, RNA/stress granule formation and glutamatergic synaptic signalling. Altogether, our findings identified novel FTLD-associated loci, and support a role for DNA methylation as a mechanism involved in the dysregulation of biological processes relevant to FTLD, highlighting novel potential avenues for therapeutic development.
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Affiliation(s)
- Katherine Fodder
- Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London, UK
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Megha Murthy
- Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London, UK
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Patrizia Rizzu
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Christina E Toomey
- Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London, UK
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, London, UK
| | - Rahat Hasan
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jack Humphrey
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Towfique Raj
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Katie Lunnon
- Department of Clinical and Biomedical Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
| | - Jonathan Mill
- Department of Clinical and Biomedical Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
| | - Peter Heutink
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
- Alector, Inc., South San Francisco, CA, USA
| | - Tammaryn Lashley
- Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London, UK
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Conceição Bettencourt
- Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London, UK.
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK.
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16
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Di Menna L, Orlando R, D'Errico G, Ginerete RP, Machaczka A, Bonaccorso CM, Arena A, Spatuzza M, Celli R, Alborghetti M, Ciocca E, Zuena AR, Scioli MR, Bruno V, Battaglia G, Nicoletti F, Catania MV. Blunted type-5 metabotropic glutamate receptor-mediated polyphosphoinositide hydrolysis in two mouse models of monogenic autism. Neuropharmacology 2023:109642. [PMID: 37392820 DOI: 10.1016/j.neuropharm.2023.109642] [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: 07/25/2022] [Revised: 06/06/2023] [Accepted: 06/20/2023] [Indexed: 07/03/2023]
Abstract
The involvement of the mGlu5 receptors in the pathophysiology of several forms of monogenic autism has been supported by numerous studies following the seminal observation that mGlu5 receptor-dependent long-term depression was enhanced in the hippocampus of mice modeling the fragile-X syndrome (FXS). Surprisingly, there are no studies examining the canonical signal transduction pathway activated by mGlu5 receptors (i.e. polyphosphoinositide - PI - hydrolysis) in mouse models of autism. We have developed a method for in vivo assessment of PI hydrolysis based on systemic injection of lithium chloride followed by treatment with the selective mGlu5 receptor PAM, VU0360172, and measurement of endogenous inositolmonophosphate (InsP) in brain tissue. Here, we report that mGlu5 receptor-mediated PI hydrolysis was blunted in the cerebral cortex, hippocampus, and corpus striatum of Ube3am-/p+ mice modeling Angelman syndrome (AS), and in the cerebral cortex and hippocampus of fmr1 knockout mice modeling FXS. In vivo mGlu5 receptor-mediated stimulation of Akt on threonine 308 was also blunted in the hippocampus of FXS mice. These changes were associated with a significant increase in cortical and striatal Homer1 levels and striatal mGlu5 receptor and Gαq levels in AS mice, and with a reduction in cortical mGlu5 receptor and hippocampal Gαq levels, and an increase in cortical phospholipase-Cβ and hippocampal Homer1 levels in FXS mice. This is the first evidence that the canonical transduction pathway activated by mGlu5 receptors is down-regulated in brain regions of mice modeling monogenic autism.
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Affiliation(s)
| | - Rosamaria Orlando
- IRCCS Neuromed, Pozzilli, Italy; Department of Physiology and Pharmacology, Sapienza University, Roma, Italy
| | | | | | - Agata Machaczka
- Department of Neurobiology, Maj Institute of Pharmacology, Polish Academy of Science, Krakow, Poland
| | | | | | | | | | - Marika Alborghetti
- Department of Neuroscience, Mental Health, and Sensory Organs, Sapienza University, Italy
| | - Eleonora Ciocca
- Department of Physiology and Pharmacology, Sapienza University, Roma, Italy
| | - Anna Rita Zuena
- Department of Physiology and Pharmacology, Sapienza University, Roma, Italy
| | | | - Valeria Bruno
- IRCCS Neuromed, Pozzilli, Italy; Department of Physiology and Pharmacology, Sapienza University, Roma, Italy
| | - Giuseppe Battaglia
- IRCCS Neuromed, Pozzilli, Italy; Department of Physiology and Pharmacology, Sapienza University, Roma, Italy
| | - Ferdinando Nicoletti
- IRCCS Neuromed, Pozzilli, Italy; Department of Physiology and Pharmacology, Sapienza University, Roma, Italy
| | - Maria Vincenza Catania
- Institute for Biomedical Research and Innovation, The National Research Council (IRIB-CNR), Catania, Italy.
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17
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Wilkerson JR, Ifrim MF, Valdez-Sinon AN, Hahn P, Bowles JE, Molinaro G, Janusz-Kaminska A, Bassell GJ, Huber KM. FMRP phosphorylation and interactions with Cdh1 regulate association with dendritic RNA granules and MEF2-triggered synapse elimination. Neurobiol Dis 2023; 182:106136. [PMID: 37120096 PMCID: PMC10370323 DOI: 10.1016/j.nbd.2023.106136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/12/2023] [Accepted: 04/24/2023] [Indexed: 05/01/2023] Open
Abstract
Fragile X Messenger Ribonucleoprotein (FMRP) is necessary for experience-dependent, developmental synapse elimination and the loss of this process may underlie the excess dendritic spines and hyperconnectivity of cortical neurons in Fragile X Syndrome, a common inherited form of intellectual disability and autism. Little is known of the signaling pathways that regulate synapse elimination and if or how FMRP is regulated during this process. We have characterized a model of synapse elimination in CA1 neurons of organotypic hippocampal slice cultures that is induced by expression of the active transcription factor Myocyte Enhancer Factor 2 (MEF2) and relies on postsynaptic FMRP. MEF2-induced synapse elimination is deficient in Fmr1 KO CA1 neurons, and is rescued by acute (24 h), postsynaptic and cell autonomous reexpression of FMRP in CA1 neurons. FMRP is an RNA binding protein that suppresses mRNA translation. Derepression is induced by posttranslational mechanisms downstream of metabotropic glutamate receptor signaling. Dephosphorylation of FMRP at S499 triggers ubiquitination and degradation of FMRP which then relieves translation suppression and promotes synthesis of proteins encoded by target mRNAs. Whether this mechanism functions in synapse elimination is not known. Here we demonstrate that phosphorylation and dephosphorylation of FMRP at S499 are both necessary for synapse elimination as well as interaction of FMRP with its E3 ligase for FMRP, APC/Cdh1. Using a bimolecular ubiquitin-mediated fluorescence complementation (UbFC) assay, we demonstrate that MEF2 promotes ubiquitination of FMRP in CA1 neurons that relies on activity and interaction with APC/Cdh1. Our results suggest a model where MEF2 regulates posttranslational modifications of FMRP via APC/Cdh1 to regulate translation of proteins necessary for synapse elimination.
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Affiliation(s)
- Julia R Wilkerson
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Marius F Ifrim
- Department of Cell and Developmental Biology, State University of New York, Upstate Medical University, Syracuse, NY 13210, USA; Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | - Patricia Hahn
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jacob E Bowles
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Gemma Molinaro
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | | | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Kimberly M Huber
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA.
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18
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Mango D, Ledonne A. Updates on the Physiopathology of Group I Metabotropic Glutamate Receptors (mGluRI)-Dependent Long-Term Depression. Cells 2023; 12:1588. [PMID: 37371058 DOI: 10.3390/cells12121588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/01/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
Group I metabotropic glutamate receptors (mGluRI), including mGluR1 and mGluR5 subtypes, modulate essential brain functions by affecting neuronal excitability, intracellular calcium dynamics, protein synthesis, dendritic spine formation, and synaptic transmission and plasticity. Nowadays, it is well appreciated that the mGluRI-dependent long-term depression (LTD) of glutamatergic synaptic transmission (mGluRI-LTD) is a key mechanism by which mGluRI shapes connectivity in various cerebral circuitries, directing complex brain functions and behaviors, and that it is deranged in several neurological and psychiatric illnesses, including neurodevelopmental disorders, neurodegenerative diseases, and psychopathologies. Here, we will provide an updated overview of the physiopathology of mGluRI-LTD, by describing mechanisms of induction and regulation by endogenous mGluRI interactors, as well as functional physiological implications and pathological deviations.
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Affiliation(s)
- Dalila Mango
- School of Pharmacy, University of Rome "Tor Vergata", 00133 Rome, Italy
- Laboratory of Pharmacology of Synaptic Plasticity, European Brain Research Institute, 00161 Rome, Italy
| | - Ada Ledonne
- Department of Systems Medicine, University of Rome "Tor Vergata", 00133 Rome, Italy
- Department of Experimental Neuroscience, IRCCS Fondazione Santa Lucia, 00143 Rome, Italy
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19
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Ghane MA, Wei W, Yakout DW, Allen ZD, Miller CL, Dong B, Yang JJ, Fang N, Mabb AM. Arc ubiquitination regulates endoplasmic reticulum-mediated Ca 2+ release and CaMKII signaling. Front Cell Neurosci 2023; 17:1091324. [PMID: 36998269 PMCID: PMC10043188 DOI: 10.3389/fncel.2023.1091324] [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: 11/06/2022] [Accepted: 02/22/2023] [Indexed: 03/17/2023] Open
Abstract
Synaptic plasticity relies on rapid, yet spatially precise signaling to alter synaptic strength. Arc is a brain enriched protein that is rapidly expressed during learning-related behaviors and is essential for regulating metabotropic glutamate receptor-mediated long-term depression (mGluR-LTD). We previously showed that disrupting the ubiquitination capacity of Arc enhances mGluR-LTD; however, the consequences of Arc ubiquitination on other mGluR-mediated signaling events is poorly characterized. Here we find that pharmacological activation of Group I mGluRs with S-3,5-dihydroxyphenylglycine (DHPG) increases Ca2+ release from the endoplasmic reticulum (ER). Disrupting Arc ubiquitination on key amino acid residues enhances DHPG-induced ER-mediated Ca2+ release. These alterations were observed in all neuronal subregions except secondary branchpoints. Deficits in Arc ubiquitination altered Arc self-assembly and enhanced its interaction with calcium/calmodulin-dependent protein kinase IIb (CaMKIIb) and constitutively active forms of CaMKII in HEK293 cells. Colocalization of Arc and CaMKII was altered in cultured hippocampal neurons, with the notable exception of secondary branchpoints. Finally, disruptions in Arc ubiquitination were found to increase Arc interaction with the integral ER protein Calnexin. These results suggest a previously unknown role for Arc ubiquitination in the fine tuning of ER-mediated Ca2+ signaling that may support mGluR-LTD, which in turn, may regulate CaMKII and its interactions with Arc.
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Affiliation(s)
- Mohammad A. Ghane
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
| | - Wei Wei
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
| | - Dina W. Yakout
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
| | - Zachary D. Allen
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
| | - Cassandra L. Miller
- Department of Chemistry, Georgia State University, Atlanta, GA, United States
| | - Bin Dong
- Department of Chemistry, Georgia State University, Atlanta, GA, United States
| | - Jenny J. Yang
- Department of Chemistry, Georgia State University, Atlanta, GA, United States
- Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, United States
| | - Ning Fang
- Department of Chemistry, Georgia State University, Atlanta, GA, United States
| | - Angela M. Mabb
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
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20
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Luo L, Yang L, Zhang K, Zhou SM, Wang Y, Yang LK, Feng B, Liu SB, Wu YM, Zhao MG, Yang Q. Caveolin-1-Mediated Cholesterol Accumulation Contributes to Exaggerated mGluR-Dependent Long-Term Depression and Impaired Cognition in Fmr1 Knockout Mice. Mol Neurobiol 2023; 60:3379-3395. [PMID: 36854997 PMCID: PMC10122623 DOI: 10.1007/s12035-023-03269-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 02/08/2023] [Indexed: 03/02/2023]
Abstract
Fragile X syndrome (FXS) is one of the most common inherited mental retardation diseases and is caused by the loss of fragile X mental retardation protein (FMRP) expression. The metabotropic glutamate receptor (mGluR) theory of FXS states that enhanced mGluR-dependent long-term depression (LTD) due to FMRP loss is involved in aberrant synaptic plasticity and autistic-like behaviors, but little is known about the underlying molecular mechanism. Here, we found that only hippocampal mGluR-LTD was exaggerated in adolescent Fmr1 KO mice, while N-methyl-D-aspartate receptor (NMDAR)-LTD was intact in mice of all ages. This development-dependent alteration was related to the differential expression of caveolin-1 (Cav1), which is essential for caveolae formation. Knockdown of Cav1 restored the enhanced mGluR-LTD in Fmr1 KO mice. Moreover, hippocampal Cav1 expression in Fmr1 KO mice induced excessive endocytosis of the α-amino-3-hydroxyl-5-methyl-4-isoxazolepropionate (AMPA) receptor subunit GluA2. This process relied on mGluR1/5 activation rather than NMDAR. Interference with Cav1 expression reversed these changes. Furthermore, massive cholesterol accumulation contributed to redundant caveolae formation, which provided the platform for mGluR-triggered Cav1 coupling to GluA2. Importantly, injection of the cholesterol scavenger methyl-β-cyclodextrin (Mβ-CD) recovered AMPA receptor trafficking and markedly alleviated hyperactivity, hippocampus-dependent fear memory, and spatial memory defects in Fmr1 KO mice. Together, our findings elucidate the important role of Cav1 in mediating mGluR-LTD enhancement and further inducing AMPA receptor endocytosis and suggest that cholesterol depletion by Mβ-CD during caveolae formation may be a novel and safe strategy to treat FXS.
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Affiliation(s)
- Li Luo
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Fourth Military Medical University, Xi'an, 710038, China
| | - Le Yang
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Fourth Military Medical University, Xi'an, 710038, China
| | - Kun Zhang
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Fourth Military Medical University, Xi'an, 710038, China
| | - Shi-Meng Zhou
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, China
| | - Yan Wang
- Department of Gastroenterology and Endoscopy Center, Fourth Military Medical University, No.986 Hospital, Xi'an, 710054, China
| | - Liu-Kun Yang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, China
| | - Bin Feng
- State Key Laboratory of Military Stomatology, Department of Pharmacy, School of Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi International Joint Research Center for Oral Diseases, Fourth Military Medical University, Xi'an, 710054, China
| | - Shui-Bing Liu
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, China
| | - Yu-Mei Wu
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, China
| | - Ming-Gao Zhao
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Fourth Military Medical University, Xi'an, 710038, China
| | - Qi Yang
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Fourth Military Medical University, Xi'an, 710038, China.
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21
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Reyes CJF, Asano K. Between Order and Chaos: Understanding the Mechanism and Pathology of RAN Translation. Biol Pharm Bull 2023; 46:139-146. [PMID: 36724941 DOI: 10.1248/bpb.b22-00448] [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: 02/03/2023]
Abstract
Repeat-associated non-AUG (RAN) translation is a pathogenic mechanism in which repetitive sequences are translated into aggregation-prone proteins from multiple reading frames, even without a canonical AUG start codon. Since its discovery in spinocerebellar ataxia type 8 (SCA8) and myotonic dystrophy type 1 (DM1), RAN translation is now known to occur in the context of 12 disease-linked repeat expansions. This review discusses recent advances in understanding the regulatory mechanisms controlling RAN translation and its contribution to the pathophysiology of repeat expansion diseases. We discuss the key findings in the context of Fragile X Tremor Ataxia Syndrome (FXTAS), a neurodegenerative disorder caused by a CGG repeat expansion in the 5' untranslated region of FMR1.
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Affiliation(s)
| | - Katsura Asano
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University.,Laboratory of Translational Control Study, Graduate School of Integrated Sciences for Life, Hiroshima University.,Hiroshima Research Center for Healthy Aging, Hiroshima University
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22
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Development of single-molecule ubiquitination mediated fluorescence complementation to visualize protein ubiquitination dynamics in dendrites. Cell Rep 2022; 41:111658. [PMID: 36384114 PMCID: PMC9795412 DOI: 10.1016/j.celrep.2022.111658] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/13/2022] [Accepted: 10/21/2022] [Indexed: 11/17/2022] Open
Abstract
The ubiquitination/proteasome system is important for the spatiotemporal control of protein synthesis and degradation at synapses, while dysregulation may underlie autism spectrum disorders (ASDs). However, methods allowing direct visualization of the subcellular localization and temporal dynamics of protein ubiquitination are lacking. Here we report the development of Single-Molecule Ubiquitin Mediated Fluorescence Complementation (SM-UbFC) as a method to visualize and quantify the dynamics of protein ubiquitination in dendrites of live neurons in culture. Using SM-UbFC, we demonstrate that the rate of PSD-95 ubiquitination is elevated in dendrites of FMR1 KO neurons compared with wild-type controls. We further demonstrate the rapid ubiquitination of the fragile X messenger ribonucleoprotein, FMRP, and the AMPA receptor subunit, GluA1, which are known to be key events in the regulation of synaptic protein synthesis and plasticity. SM-UbFC will be useful for future studies on the regulation of synaptic protein homeostasis.
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23
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Purushotham SS, Reddy NMN, D'Souza MN, Choudhury NR, Ganguly A, Gopalakrishna N, Muddashetty R, Clement JP. A perspective on molecular signalling dysfunction, its clinical relevance and therapeutics in autism spectrum disorder. Exp Brain Res 2022; 240:2525-2567. [PMID: 36063192 DOI: 10.1007/s00221-022-06448-x] [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: 06/01/2022] [Accepted: 08/18/2022] [Indexed: 11/29/2022]
Abstract
Intellectual disability (ID) and autism spectrum disorder (ASD) are neurodevelopmental disorders that have become a primary clinical and social concern, with a prevalence of 2-3% in the population. Neuronal function and behaviour undergo significant malleability during the critical period of development that is found to be impaired in ID/ASD. Human genome sequencing studies have revealed many genetic variations associated with ASD/ID that are further verified by many approaches, including many mouse and other models. These models have facilitated the identification of fundamental mechanisms underlying the pathogenesis of ASD/ID, and several studies have proposed converging molecular pathways in ASD/ID. However, linking the mechanisms of the pathogenic genes and their molecular characteristics that lead to ID/ASD has progressed slowly, hampering the development of potential therapeutic strategies. This review discusses the possibility of recognising the common molecular causes for most ASD/ID based on studies from the available models that may enable a better therapeutic strategy to treat ID/ASD. We also reviewed the potential biomarkers to detect ASD/ID at early stages that may aid in diagnosis and initiating medical treatment, the concerns with drug failure in clinical trials, and developing therapeutic strategies that can be applied beyond a particular mutation associated with ASD/ID.
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Affiliation(s)
- Sushmitha S Purushotham
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, 560064, India
| | - Neeharika M N Reddy
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, 560064, India
| | - Michelle Ninochka D'Souza
- Centre for Brain Research, Indian Institute of Science Campus, CV Raman Avenue, Bangalore, 560 012, India.,The University of Trans-Disciplinary Health Sciences and Technology (TDU), Bangalore, 560064, India
| | - Nilpawan Roy Choudhury
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, 560064, India
| | - Anusa Ganguly
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, 560064, India
| | - Niharika Gopalakrishna
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, 560064, India
| | - Ravi Muddashetty
- Centre for Brain Research, Indian Institute of Science Campus, CV Raman Avenue, Bangalore, 560 012, India.,The University of Trans-Disciplinary Health Sciences and Technology (TDU), Bangalore, 560064, India
| | - James P Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, 560064, India.
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24
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Jeon SJ, Kwon H, Bae HJ, Gonzales EL, Kim J, Chung HJ, Kim DH, Ryu JH, Shin CY. Agmatine relieves behavioral impairments in Fragile X mice model. Neuropharmacology 2022; 219:109234. [PMID: 36057317 DOI: 10.1016/j.neuropharm.2022.109234] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 07/25/2022] [Accepted: 08/21/2022] [Indexed: 10/31/2022]
Abstract
BACKGROUND Fragile X syndrome (FXS) is the most common heritable form of neurodevelopmental disorder, which is caused by the loss of fragile X mental retardation protein (FMRP) expression. Despite the unceasing efforts to develop therapeutic agents against FXS based on the pathophysiological changes observed in animal models of FXS and human patients, therapeutic candidates including mGluR signaling modulators have failed to provide sufficient effects. Based on the recent successful demonstration of an endogenous polyamine, agmatine, to improve the autism-like symptoms in the valproic acid animal model of autism, we investigated the effects of agmatine against FXS symptoms using Fmr1 knockout (KO) mice. METHODS We used male Fmr1 KO mice for behavioral tests such as marble burying, open-field test, memory tasks, social interaction tests and startle response to confirm the symptoms of FXS. We also checked the electrophysiological profile of neural activity in agmatine-treated Fmr1 KO mice. RESULTS Agmatine reversed the compulsion, learning and memory deficits, hyperactivity, aberrant social interaction, and communication deficit in Fmr1 KO mice while it normalized the aberrant LTP and LTD in the hippocampus. CONCLUSIONS The results highlight the potential of agmatine's novel disease-ameliorating effects in FXS, which warrants further studies to ascertain whether these findings translate into clinical effects in FXS patients.
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Affiliation(s)
- Se Jin Jeon
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea; Department of Integrative Biotechnology, College of Science and Technology, Sahmyook University, Seoul, 01795, Republic of Korea
| | - Huiyoung Kwon
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea
| | - Ho Jung Bae
- Department of Life and Nanopharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul, 02447, Republic of Korea
| | - Edson Luck Gonzales
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea
| | - Junhyeong Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Hye Jin Chung
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Dong Hyun Kim
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea
| | - Jong Hoon Ryu
- Department of Life and Nanopharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul, 02447, Republic of Korea
| | - Chan Young Shin
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea.
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25
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Triantopoulou N, Vidaki M. Local mRNA translation and cytoskeletal reorganization: Mechanisms that tune neuronal responses. Front Mol Neurosci 2022; 15:949096. [PMID: 35979146 PMCID: PMC9376447 DOI: 10.3389/fnmol.2022.949096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 07/07/2022] [Indexed: 12/31/2022] Open
Abstract
Neurons are highly polarized cells with significantly long axonal and dendritic extensions that can reach distances up to hundreds of centimeters away from the cell bodies in higher vertebrates. Their successful formation, maintenance, and proper function highly depend on the coordination of intricate molecular networks that allow axons and dendrites to quickly process information, and respond to a continuous and diverse cascade of environmental stimuli, often without enough time for communication with the soma. Two seemingly unrelated processes, essential for these rapid responses, and thus neuronal homeostasis and plasticity, are local mRNA translation and cytoskeletal reorganization. The axonal cytoskeleton is characterized by high stability and great plasticity; two contradictory attributes that emerge from the powerful cytoskeletal rearrangement dynamics. Cytoskeletal reorganization is crucial during nervous system development and in adulthood, ensuring the establishment of proper neuronal shape and polarity, as well as regulating intracellular transport and synaptic functions. Local mRNA translation is another mechanism with a well-established role in the developing and adult nervous system. It is pivotal for axonal guidance and arborization, synaptic formation, and function and seems to be a key player in processes activated after neuronal damage. Perturbations in the regulatory pathways of local translation and cytoskeletal reorganization contribute to various pathologies with diverse clinical manifestations, ranging from intellectual disabilities (ID) to autism spectrum disorders (ASD) and schizophrenia (SCZ). Despite the fact that both processes are essential for the orchestration of pathways critical for proper axonal and dendritic function, the interplay between them remains elusive. Here we review our current knowledge on the molecular mechanisms and specific interaction networks that regulate and potentially coordinate these interconnected processes.
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Affiliation(s)
- Nikoletta Triantopoulou
- Division of Basic Sciences, Medical School, University of Crete, Heraklion, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas (IMBB-FORTH), Heraklion, Greece
| | - Marina Vidaki
- Division of Basic Sciences, Medical School, University of Crete, Heraklion, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas (IMBB-FORTH), Heraklion, Greece
- *Correspondence: Marina Vidaki,
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26
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Bhat VD, Jayaraj J, Babu K. RNA and neuronal function: the importance of post-transcriptional regulation. OXFORD OPEN NEUROSCIENCE 2022; 1:kvac011. [PMID: 38596700 PMCID: PMC10913846 DOI: 10.1093/oons/kvac011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/03/2022] [Accepted: 05/28/2022] [Indexed: 04/11/2024]
Abstract
The brain represents an organ with a particularly high diversity of genes that undergo post-transcriptional gene regulation through multiple mechanisms that affect RNA metabolism and, consequently, brain function. This vast regulatory process in the brain allows for a tight spatiotemporal control over protein expression, a necessary factor due to the unique morphologies of neurons. The numerous mechanisms of post-transcriptional regulation or translational control of gene expression in the brain include alternative splicing, RNA editing, mRNA stability and transport. A large number of trans-elements such as RNA-binding proteins and micro RNAs bind to specific cis-elements on transcripts to dictate the fate of mRNAs including its stability, localization, activation and degradation. Several trans-elements are exemplary regulators of translation, employing multiple cofactors and regulatory machinery so as to influence mRNA fate. Networks of regulatory trans-elements exert control over key neuronal processes such as neurogenesis, synaptic transmission and plasticity. Perturbations in these networks may directly or indirectly cause neuropsychiatric and neurodegenerative disorders. We will be reviewing multiple mechanisms of gene regulation by trans-elements occurring specifically in neurons.
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Affiliation(s)
- Vandita D Bhat
- Centre for Neuroscience, Indian Institute of Science, CV Raman Road, Bangalore 560012, Karnataka, India
| | - Jagannath Jayaraj
- Centre for Neuroscience, Indian Institute of Science, CV Raman Road, Bangalore 560012, Karnataka, India
| | - Kavita Babu
- Centre for Neuroscience, Indian Institute of Science, CV Raman Road, Bangalore 560012, Karnataka, India
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27
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Malone TJ, Kaczmarek LK. The role of altered translation in intellectual disability and epilepsy. Prog Neurobiol 2022; 213:102267. [PMID: 35364140 PMCID: PMC10583652 DOI: 10.1016/j.pneurobio.2022.102267] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 02/18/2022] [Accepted: 03/24/2022] [Indexed: 11/29/2022]
Abstract
A very high proportion of cases of intellectual disability are genetic in origin and are associated with the occurrence of epileptic seizures during childhood. These two disorders together effect more than 5% of the world's population. One feature linking the two diseases is that learning and memory require the synthesis of new synaptic components and ion channels, while maintenance of overall excitability also requires synthesis of similar proteins in response to altered neuronal stimulation. Many of these disorders result from mutations in proteins that regulate mRNA processing, translation initiation, translation elongation, mRNA stability or upstream translation modulators. One theme that emerges on reviewing this field is that mutations in proteins that regulate changes in translation following neuronal stimulation are more likely to result in epilepsy with intellectual disability than general translation regulators with no known role in activity-dependent changes. This is consistent with the notion that activity-dependent translation in neurons differs from that in other cells types in that the changes in local cellular composition, morphology and connectivity that occur generally in response to stimuli are directly coupled to local synaptic activity and persist for months or years after the original stimulus.
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Affiliation(s)
- Taylor J Malone
- Departments of Pharmacology, and of Cellular & Molecular Physiology, Yale University, 333 Cedar Street B-309, New Haven, CT 06520, USA
| | - Leonard K Kaczmarek
- Departments of Pharmacology, and of Cellular & Molecular Physiology, Yale University, 333 Cedar Street B-309, New Haven, CT 06520, USA.
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28
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D’Incal C, Broos J, Torfs T, Kooy RF, Vanden Berghe W. Towards Kinase Inhibitor Therapies for Fragile X Syndrome: Tweaking Twists in the Autism Spectrum Kinase Signaling Network. Cells 2022; 11:cells11081325. [PMID: 35456004 PMCID: PMC9029738 DOI: 10.3390/cells11081325] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/01/2022] [Accepted: 04/03/2022] [Indexed: 12/12/2022] Open
Abstract
Absence of the Fragile X Mental Retardation Protein (FMRP) causes autism spectrum disorders and intellectual disability, commonly referred to as the Fragile X syndrome. FMRP is a negative regulator of protein translation and is essential for neuronal development and synapse formation. FMRP is a target for several post-translational modifications (PTMs) such as phosphorylation and methylation, which tightly regulate its cellular functions. Studies have indicated the involvement of FMRP in a multitude of cellular pathways, and an absence of FMRP was shown to affect several neurotransmitter receptors, for example, the GABA receptor and intracellular signaling molecules such as Akt, ERK, mTOR, and GSK3. Interestingly, many of these molecules function as protein kinases or phosphatases and thus are potentially amendable by pharmacological treatment. Several treatments acting on these kinase-phosphatase systems have been shown to be successful in preclinical models; however, they have failed to convincingly show any improvements in clinical trials. In this review, we highlight the different protein kinase and phosphatase studies that have been performed in the Fragile X syndrome. In our opinion, some of the paradoxical study conclusions are potentially due to the lack of insight into integrative kinase signaling networks in the disease. Quantitative proteome analyses have been performed in several models for the FXS to determine global molecular processes in FXS. However, only one phosphoproteomics study has been carried out in Fmr1 knock-out mouse embryonic fibroblasts, and it showed dysfunctional protein kinase and phosphatase signaling hubs in the brain. This suggests that the further use of phosphoproteomics approaches in Fragile X syndrome holds promise for identifying novel targets for kinase inhibitor therapies.
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Affiliation(s)
- Claudio D’Incal
- Protein Chemistry, Proteomics and Epigenetic Signaling (PPES), Department of Biomedical Sciences, University of Antwerp, 2000 Antwerp, Belgium; (C.D.); (J.B.); (T.T.)
- Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium;
| | - Jitse Broos
- Protein Chemistry, Proteomics and Epigenetic Signaling (PPES), Department of Biomedical Sciences, University of Antwerp, 2000 Antwerp, Belgium; (C.D.); (J.B.); (T.T.)
| | - Thierry Torfs
- Protein Chemistry, Proteomics and Epigenetic Signaling (PPES), Department of Biomedical Sciences, University of Antwerp, 2000 Antwerp, Belgium; (C.D.); (J.B.); (T.T.)
| | - R. Frank Kooy
- Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium;
| | - Wim Vanden Berghe
- Protein Chemistry, Proteomics and Epigenetic Signaling (PPES), Department of Biomedical Sciences, University of Antwerp, 2000 Antwerp, Belgium; (C.D.); (J.B.); (T.T.)
- Correspondence: ; Tel.: +0032-(0)-32-652-657
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29
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Liu X, Kumar V, Tsai NP, Auerbach BD. Hyperexcitability and Homeostasis in Fragile X Syndrome. Front Mol Neurosci 2022; 14:805929. [PMID: 35069112 PMCID: PMC8770333 DOI: 10.3389/fnmol.2021.805929] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 12/14/2021] [Indexed: 01/13/2023] Open
Abstract
Fragile X Syndrome (FXS) is a leading inherited cause of autism and intellectual disability, resulting from a mutation in the FMR1 gene and subsequent loss of its protein product FMRP. Despite this simple genetic origin, FXS is a phenotypically complex disorder with a range of physical and neurocognitive disruptions. While numerous molecular and cellular pathways are affected by FMRP loss, there is growing evidence that circuit hyperexcitability may be a common convergence point that can account for many of the wide-ranging phenotypes seen in FXS. The mechanisms for hyperexcitability in FXS include alterations to excitatory synaptic function and connectivity, reduced inhibitory neuron activity, as well as changes to ion channel expression and conductance. However, understanding the impact of FMR1 mutation on circuit function is complicated by the inherent plasticity in neural circuits, which display an array of homeostatic mechanisms to maintain activity near set levels. FMRP is also an important regulator of activity-dependent plasticity in the brain, meaning that dysregulated plasticity can be both a cause and consequence of hyperexcitable networks in FXS. This makes it difficult to separate the direct effects of FMR1 mutation from the myriad and pleiotropic compensatory changes associated with it, both of which are likely to contribute to FXS pathophysiology. Here we will: (1) review evidence for hyperexcitability and homeostatic plasticity phenotypes in FXS models, focusing on similarities/differences across brain regions, cell-types, and developmental time points; (2) examine how excitability and plasticity disruptions interact with each other to ultimately contribute to circuit dysfunction in FXS; and (3) discuss how these synaptic and circuit deficits contribute to disease-relevant behavioral phenotypes like epilepsy and sensory hypersensitivity. Through this discussion of where the current field stands, we aim to introduce perspectives moving forward in FXS research.
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Affiliation(s)
- Xiaopeng Liu
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Beckman Institute for Advanced Science & Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Vipendra Kumar
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Nien-Pei Tsai
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Benjamin D. Auerbach
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Beckman Institute for Advanced Science & Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- *Correspondence: Benjamin D. Auerbach
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30
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Zhang A, Sokolova I, Domissy A, Davis J, Rao L, Hana Utami K, Wang Y, Hagerman RJ, Pouladi MA, Sanna P, Boland MJ, Loring JF. OUP accepted manuscript. Stem Cells Transl Med 2022; 11:613-629. [PMID: 35556144 PMCID: PMC9216490 DOI: 10.1093/stcltm/szac022] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 02/25/2022] [Indexed: 12/03/2022] Open
Abstract
Fragile X Syndrome (FXS), the leading monogenic cause of intellectual disability and autism spectrum disorder, is caused by expansion of a CGG trinucleotide repeat in the 5ʹ-UTR of the Fragile X Mental Retardation-1 (FMR1) gene. Epigenetic silencing of FMR1 results in loss of the Fragile X Mental Retardation Protein (FMRP). Although most studies to date have focused on excitatory neurons, recent evidence suggests that GABAergic inhibitory networks are also affected. To investigate human GABAergic neurogenesis, we established a method to reproducibly derive inhibitory neurons from multiple FXS and control human pluripotent stem cell (hPSC) lines. Electrophysiological analyses suggested that the developing FXS neurons had a delay in the GABA functional switch, a transition in fetal development that converts the GABAA channel’s function from depolarization to hyperpolarization, with profound effects on the developing brain. To investigate the cause of this delay, we analyzed 14 400 single-cell transcriptomes from FXS and control cells at 2 stages of GABAergic neurogenesis. While control and FXS cells were similar at the earlier time point, the later-stage FXS cells retained expression of neuroblast proliferation-associated genes and had lower levels of genes associated with action potential regulation, synapses, and mitochondria compared with controls. Our analysis suggests that loss of FMRP prolongs the proliferative stage of progenitors, which may result in more neurons remaining immature during the later stages of neurogenesis. This could have profound implications for homeostatic excitatory-inhibitory circuit development in FXS, and suggests a novel direction for understanding disease mechanisms that may help to guide therapeutic interventions.
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Affiliation(s)
- Ai Zhang
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA
- Skaggs Graduate School of Chemical and Biological Sciences, Scripps Research, La Jolla, CA, USA
- Aspen Neuroscience, Inc.San Diego, CA, USA
| | - Irina Sokolova
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA, USA
| | - Alain Domissy
- Center for Computational Biology, Scripps Research, La Jolla, CA, USA
| | - Joshua Davis
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA
| | - Lee Rao
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA
- Biological and Medical Informatics Graduate Program, University of California, San Francisco, CA, USA
| | - Kagistia Hana Utami
- Department of Physiology, National University of Singapore, Singapore
- Translational Laboratory in Genetic Medicine, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Yanling Wang
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL, USA
| | - Randi J Hagerman
- MIND Institute, University of California Davis, Sacramento, CA, USA
| | - Mahmoud A Pouladi
- Department of Physiology, National University of Singapore, Singapore
- Translational Laboratory in Genetic Medicine, Agency for Science, Technology and Research (A*STAR), Singapore
- British Columbia Children’s Hospital Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Pietro Sanna
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA, USA
| | - Michael J Boland
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Neurology, Columbia University, New York, NY, USA
| | - Jeanne F Loring
- Corresponding author: Jeanne F. Loring, Department of Molecular Medicine, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA;
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31
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Romagnoli A, Di Marino D. The Use of Peptides in the Treatment of Fragile X Syndrome: Challenges and Opportunities. Front Psychiatry 2021; 12:754485. [PMID: 34803767 PMCID: PMC8599826 DOI: 10.3389/fpsyt.2021.754485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/11/2021] [Indexed: 01/17/2023] Open
Abstract
Fragile X Syndrome (FXS) is the most frequent cause of inherited intellectual disabilities and autism spectrum disorders, characterized by cognitive deficits and autistic behaviors. The silencing of the Fmr1 gene and consequent lack of FMRP protein, is the major contribution to FXS pathophysiology. FMRP is an RNA binding protein involved in the maturation and plasticity of synapses and its absence culminates in a range of morphological, synaptic and behavioral phenotypes. Currently, there are no approved medications for the treatment of FXS, with the approaches under study being fairly specific and unsatisfying in human trials. Here we propose peptides/peptidomimetics as candidates in the pharmacotherapy of FXS; in the last years this class of molecules has catalyzed the attention of pharmaceutical research, being highly selective and well-tolerated. Thanks to their ability to target protein-protein interactions (PPIs), they are already being tested for a wide range of diseases, including cancer, diabetes, inflammation, Alzheimer's disease, but this approach has never been applied to FXS. As FXS is at the forefront of efforts to develop new drugs and approaches, we discuss opportunities, challenges and potential issues of peptides/peptidomimetics in FXS drug design and development.
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Affiliation(s)
| | - Daniele Di Marino
- Department of Life and Environmental Sciences, New York-Marche Structural Biology Center (NY-MaSBiC), Polytechnic University of Marche, Ancona, Italy
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32
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Cell-type-specific disruption of PERK-eIF2α signaling in dopaminergic neurons alters motor and cognitive function. Mol Psychiatry 2021; 26:6427-6450. [PMID: 33879865 PMCID: PMC8526653 DOI: 10.1038/s41380-021-01099-w] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 03/20/2021] [Accepted: 04/01/2021] [Indexed: 02/02/2023]
Abstract
Endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) has been shown to activate the eIF2α kinase PERK to directly regulate translation initiation. Tight control of PERK-eIF2α signaling has been shown to be necessary for normal long-lasting synaptic plasticity and cognitive function, including memory. In contrast, chronic activation of PERK-eIF2α signaling has been shown to contribute to pathophysiology, including memory impairments, associated with multiple neurological diseases, making this pathway an attractive therapeutic target. Herein, using multiple genetic approaches we show that selective deletion of the PERK in mouse midbrain dopaminergic (DA) neurons results in multiple cognitive and motor phenotypes. Conditional expression of phospho-mutant eIF2α in DA neurons recapitulated the phenotypes caused by deletion of PERK, consistent with a causal role of decreased eIF2α phosphorylation for these phenotypes. In addition, deletion of PERK in DA neurons resulted in altered de novo translation, as well as changes in axonal DA release and uptake in the striatum that mirror the pattern of motor changes observed. Taken together, our findings show that proper regulation of PERK-eIF2α signaling in DA neurons is required for normal cognitive and motor function in a non-pathological state, and also provide new insight concerning the onset of neuropsychiatric disorders that accompany UPR failure.
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33
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Bui TA, Shatto J, Cuppens T, Droit A, Bolduc FV. Phenotypic Trade-Offs: Deciphering the Impact of Neurodiversity on Drug Development in Fragile X Syndrome. Front Psychiatry 2021; 12:730987. [PMID: 34733188 PMCID: PMC8558248 DOI: 10.3389/fpsyt.2021.730987] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 09/20/2021] [Indexed: 11/24/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common single-gene cause of intellectual disability and autism spectrum disorder. Individuals with FXS present with a wide range of severity in multiple phenotypes including cognitive delay, behavioral challenges, sleep issues, epilepsy, and anxiety. These symptoms are also shared by many individuals with other neurodevelopmental disorders (NDDs). Since the discovery of the FXS gene, FMR1, FXS has been the focus of intense preclinical investigation and is placed at the forefront of clinical trials in the field of NDDs. So far, most studies have aimed to translate the rescue of specific phenotypes in animal models, for example, learning, or improving general cognitive or behavioral functioning in individuals with FXS. Trial design, selection of outcome measures, and interpretation of results of recent trials have shown limitations in this type of approach. We propose a new paradigm in which all phenotypes involved in individuals with FXS would be considered and, more importantly, the possible interactions between these phenotypes. This approach would be implemented both at the baseline, meaning when entering a trial or when studying a patient population, and also after the intervention when the study subjects have been exposed to the investigational product. This approach would allow us to further understand potential trade-offs underlying the varying effects of the treatment on different individuals in clinical trials, and to connect the results to individual genetic differences. To better understand the interplay between different phenotypes, we emphasize the need for preclinical studies to investigate various interrelated biological and behavioral outcomes when assessing a specific treatment. In this paper, we present how such a conceptual shift in preclinical design could shed new light on clinical trial results. Future clinical studies should take into account the rich neurodiversity of individuals with FXS specifically and NDDs in general, and incorporate the idea of trade-offs in their designs.
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Affiliation(s)
- Truong An Bui
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
| | - Julie Shatto
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
| | - Tania Cuppens
- Centre de Recherche du CHU de Québec-Université Laval et Département de Médecine Moléculaire de l'Université Laval, Laval, QC, Canada
| | - Arnaud Droit
- Centre de Recherche du CHU de Québec-Université Laval et Département de Médecine Moléculaire de l'Université Laval, Laval, QC, Canada
| | - François V. Bolduc
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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34
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Fernandes G, Mishra PK, Nawaz MS, Donlin-Asp PG, Rahman MM, Hazra A, Kedia S, Kayenaat A, Songara D, Wyllie DJA, Schuman EM, Kind PC, Chattarji S. Correction of amygdalar dysfunction in a rat model of fragile X syndrome. Cell Rep 2021; 37:109805. [PMID: 34644573 DOI: 10.1016/j.celrep.2021.109805] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 07/19/2021] [Accepted: 09/16/2021] [Indexed: 10/20/2022] Open
Abstract
Fragile X syndrome (FXS), a commonly inherited form of autism and intellectual disability, is associated with emotional symptoms that implicate dysfunction of the amygdala. However, current understanding of the pathogenesis of the disease is based primarily on studies in the hippocampus and neocortex, where FXS defects have been corrected by inhibiting group I metabotropic glutamate receptors (mGluRs). Here, we observe that activation, rather than inhibition, of mGluRs in the basolateral amygdala reverses impairments in a rat model of FXS. FXS rats exhibit deficient recall of auditory conditioned fear, which is accompanied by a range of in vitro and in vivo deficits in synaptic transmission and plasticity. We find presynaptic mGluR5 in the amygdala, activation of which reverses deficient synaptic transmission and plasticity, thereby restoring normal fear learning in FXS rats. This highlights the importance of modifying the prevailing mGluR-based framework for therapeutic strategies to include circuit-specific differences in FXS pathophysiology.
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Affiliation(s)
- Giselle Fernandes
- National Centre for Biological Sciences, TIFR, Bangalore 560065, India
| | - Pradeep K Mishra
- National Centre for Biological Sciences, TIFR, Bangalore 560065, India; Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore 560065, India
| | - Mohammad Sarfaraz Nawaz
- National Centre for Biological Sciences, TIFR, Bangalore 560065, India; Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore 560065, India
| | | | - Mohammed Mostafizur Rahman
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Anupam Hazra
- National Centre for Biological Sciences, TIFR, Bangalore 560065, India; Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore 560065, India
| | - Sonal Kedia
- Department of Biology, Brandeis University, Waltham, MA, USA
| | - Aiman Kayenaat
- National Centre for Biological Sciences, TIFR, Bangalore 560065, India; Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore 560065, India; University of Transdisciplinary Health Sciences and Technology, Bangalore 560064, India
| | - Dheeraj Songara
- National Centre for Biological Sciences, TIFR, Bangalore 560065, India
| | - David J A Wyllie
- Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore 560065, India; Simons Initiative for the Developing Brain and Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Erin M Schuman
- Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Peter C Kind
- Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore 560065, India; Simons Initiative for the Developing Brain and Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Sumantra Chattarji
- National Centre for Biological Sciences, TIFR, Bangalore 560065, India; Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore 560065, India; Simons Initiative for the Developing Brain and Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK.
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35
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Ferreira JS, Kellermayer B, Carvalho AL, Groc L. Interplay between NMDA receptor dynamics and the synaptic proteasome. Eur J Neurosci 2021; 54:6000-6011. [PMID: 34405467 DOI: 10.1111/ejn.15427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/16/2021] [Accepted: 08/11/2021] [Indexed: 10/20/2022]
Abstract
Proteasome activity at the excitatory synapse plays an important role in neuronal communication. The proteasome translocation to synapses is mediated by neuronal activity, in particular the activation of N-methyl-d-aspartate receptors (NMDARs). These receptors are composed of different subunits with distinct trafficking properties that provide various signalling and plasticity features to the synapse. Yet whether the interplay between the proteasome and NMDAR relies on specific subunit properties remain unclear. Using a combination of single molecule and immunocytochemistry imaging approaches in rat hippocampal neurons, we unveil a specific interplay between GluN2B-containing NMDARs (GluN2B-NMDARs) and the synaptic proteasome. Sustained proteasome activation specifically increases GluN2B-NMDAR (not GluN2A-NMDAR) lateral diffusion. In addition, when GluN2B-NMDAR expression is downregulated, the proteasome localization decreases at glutamatergic synapses. Collectively, our data fuel a model in which the cellular dynamics and location of GluN2B-NMDARs and proteasome are intermingled, shedding new lights on the NMDAR-dependent regulation of synaptic adaptation.
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Affiliation(s)
- Joana S Ferreira
- IINS-Interdisciplinary Institute for Neuroscience, CNRS, UMR 5297, University of Bordeaux, Bordeaux, France
| | - Blanka Kellermayer
- IINS-Interdisciplinary Institute for Neuroscience, CNRS, UMR 5297, University of Bordeaux, Bordeaux, France.,CNC-Center for Neuroscience and Cell Biology of Coimbra, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Ana Luísa Carvalho
- CNC-Center for Neuroscience and Cell Biology of Coimbra, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Laurent Groc
- IINS-Interdisciplinary Institute for Neuroscience, CNRS, UMR 5297, University of Bordeaux, Bordeaux, France
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36
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Bengani H, Grozeva D, Moyon L, Bhatia S, Louros SR, Hope J, Jackson A, Prendergast JG, Owen LJ, Naville M, Rainger J, Grimes G, Halachev M, Murphy LC, Spasic-Boskovic O, van Heyningen V, Kind P, Abbott CM, Osterweil E, Raymond FL, Roest Crollius H, FitzPatrick DR. Identification and functional modelling of plausibly causative cis-regulatory variants in a highly-selected cohort with X-linked intellectual disability. PLoS One 2021; 16:e0256181. [PMID: 34388204 PMCID: PMC8362966 DOI: 10.1371/journal.pone.0256181] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/01/2021] [Indexed: 11/18/2022] Open
Abstract
Identifying causative variants in cis-regulatory elements (CRE) in neurodevelopmental disorders has proven challenging. We have used in vivo functional analyses to categorize rigorously filtered CRE variants in a clinical cohort that is plausibly enriched for causative CRE mutations: 48 unrelated males with a family history consistent with X-linked intellectual disability (XLID) in whom no detectable cause could be identified in the coding regions of the X chromosome (chrX). Targeted sequencing of all chrX CRE identified six rare variants in five affected individuals that altered conserved bases in CRE targeting known XLID genes and segregated appropriately in families. Two of these variants, FMR1CRE and TENM1CRE, showed consistent site- and stage-specific differences of enhancer function in the developing zebrafish brain using dual-color fluorescent reporter assay. Mouse models were created for both variants. In male mice Fmr1CRE induced alterations in neurodevelopmental Fmr1 expression, olfactory behavior and neurophysiological indicators of FMRP function. The absence of another likely causative variant on whole genome sequencing further supported FMR1CRE as the likely basis of the XLID in this family. Tenm1CRE mice showed no phenotypic anomalies. Following the release of gnomAD 2.1, reanalysis showed that TENM1CRE exceeded the maximum plausible population frequency of a XLID causative allele. Assigning causative status to any ultra-rare CRE variant remains problematic and requires disease-relevant in vivo functional data from multiple sources. The sequential and bespoke nature of such analyses renders them time-consuming and challenging to scale for routine clinical use.
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Affiliation(s)
- Hemant Bengani
- MRC Human Genetics Unit, IGMM, University of Edinburgh (UoE), Edinburgh, United Kingdom
| | - Detelina Grozeva
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
- Institute of Psychological Medicine & Clinical Neurosciences, Cardiff University, Cardiff, United Kingdom
| | - Lambert Moyon
- Ecole Normale Supérieure, Institut de Biologie de l’ENS, IBENS, Paris, France
| | - Shipra Bhatia
- MRC Human Genetics Unit, IGMM, University of Edinburgh (UoE), Edinburgh, United Kingdom
| | - Susana R. Louros
- Centre for Discovery Brain Sciences, Patrick Wild Centre, University of Edinburgh, Edinburgh, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, United Kingdom
| | - Jilly Hope
- Institute of Genomic and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Adam Jackson
- Centre for Discovery Brain Sciences, Patrick Wild Centre, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Liusaidh J. Owen
- MRC Human Genetics Unit, IGMM, University of Edinburgh (UoE), Edinburgh, United Kingdom
| | - Magali Naville
- Ecole Normale Supérieure, Institut de Biologie de l’ENS, IBENS, Paris, France
| | - Jacqueline Rainger
- MRC Human Genetics Unit, IGMM, University of Edinburgh (UoE), Edinburgh, United Kingdom
| | - Graeme Grimes
- Institute of Genomic and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Mihail Halachev
- Institute of Genomic and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Laura C. Murphy
- Institute of Genomic and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Olivera Spasic-Boskovic
- East Midlands and East of England NHS Genomic Laboratory Hub, Molecular Genetics, Adden brooke’s Hospital, Cambridge University Hospitals NHS Foundation Trust Cambridge, Cambridge, United Kingdom
| | | | - Peter Kind
- Centre for Discovery Brain Sciences, Patrick Wild Centre, University of Edinburgh, Edinburgh, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, United Kingdom
| | - Catherine M. Abbott
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, United Kingdom
- Institute of Genomic and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Emily Osterweil
- Centre for Discovery Brain Sciences, Patrick Wild Centre, University of Edinburgh, Edinburgh, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, United Kingdom
| | - F. Lucy Raymond
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | | | - David R. FitzPatrick
- MRC Human Genetics Unit, IGMM, University of Edinburgh (UoE), Edinburgh, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, United Kingdom
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37
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Historical perspective and progress on protein ubiquitination at glutamatergic synapses. Neuropharmacology 2021; 196:108690. [PMID: 34197891 DOI: 10.1016/j.neuropharm.2021.108690] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 06/07/2021] [Accepted: 06/22/2021] [Indexed: 12/23/2022]
Abstract
Transcription-translation coupling leads to the production of proteins that are key for controlling essential neuronal processes that include neuronal development and changes in synaptic strength. Although these events have been a prevailing theme in neuroscience, the regulation of proteins via posttranslational signaling pathways are equally relevant for these neuronal processes. Ubiquitin is one type of posttranslational modification that covalently attaches to its targets/substrates. Ubiquitination of proteins play a key role in multiple signaling pathways, the predominant being removal of its substrates by a large molecular machine called the proteasome. Here, I review 40 years of progress on ubiquitination in the nervous system at glutamatergic synapses focusing on axon pathfinding, synapse formation, presynaptic release, dendritic spine formation, and regulation of postsynaptic glutamate receptors. Finally, I elucidate emerging themes in ubiquitin biology that may challenge our current understanding of ubiquitin signaling in the nervous system.
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38
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Mahaman YAR, Huang F, Embaye KS, Wang X, Zhu F. The Implication of STEP in Synaptic Plasticity and Cognitive Impairments in Alzheimer's Disease and Other Neurological Disorders. Front Cell Dev Biol 2021; 9:680118. [PMID: 34195199 PMCID: PMC8236946 DOI: 10.3389/fcell.2021.680118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/06/2021] [Indexed: 12/31/2022] Open
Abstract
STriatal-Enriched protein tyrosine Phosphatase (STEP) is a tyrosine phosphatase that has been implicated in Alzheimer’s disease (AD), the most common form of dementia, and many other neurological diseases. The protein level and activity of STEP have been found to be elevated in most of these disorders, and specifically in AD as a result of dysregulation of different pathways including PP2B/DARPP32/PP1, PKA as well as impairments of both proteasomal and lysosomal systems. The upregulation in STEP leads to increased binding to, and dephosphorylation of, its substrates which are mainly found to be synaptic plasticity and thus learning and memory related proteins. These proteins include kinases like Fyn, Pyk2, ERK1/2 and both NMDA and AMPA receptor subunits GluN2B and GluA2. The dephosphorylation of these molecules results in inactivation of these kinases and internalization of NMDA and AMPA receptor complexes leading to synapse loss and cognitive impairments. In this study, we aim to review STEP regulation and its implications in AD as well as other neurological disorders and then summarize data on targeting STEP as therapeutic strategy in these diseases.
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Affiliation(s)
- Yacoubou Abdoul Razak Mahaman
- Cognitive Impairment Ward of Neurology Department, The Third Affiliated Hospital, Shenzhen University, Shenzhen, China.,Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fang Huang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Kidane Siele Embaye
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaochuan Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Feiqi Zhu
- Cognitive Impairment Ward of Neurology Department, The Third Affiliated Hospital, Shenzhen University, Shenzhen, China
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Urbano-Gámez JD, Casañas JJ, Benito I, Montesinos ML. Prenatal treatment with rapamycin restores enhanced hippocampal mGluR-LTD and mushroom spine size in a Down's syndrome mouse model. Mol Brain 2021; 14:84. [PMID: 34034796 PMCID: PMC8152312 DOI: 10.1186/s13041-021-00795-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 05/18/2021] [Indexed: 11/10/2022] Open
Abstract
Down syndrome (DS) is the most frequent genetic cause of intellectual disability including hippocampal-dependent memory deficits. We have previously reported hippocampal mTOR (mammalian target of rapamycin) hyperactivation, and related plasticity as well as memory deficits in Ts1Cje mice, a DS experimental model. Here we characterize the proteome of hippocampal synaptoneurosomes (SNs) from these mice, and found a predicted alteration of synaptic plasticity pathways, including long term depression (LTD). Accordingly, mGluR-LTD (metabotropic Glutamate Receptor-LTD) is enhanced in the hippocampus of Ts1Cje mice and this is correlated with an increased proportion of a particular category of mushroom spines in hippocampal pyramidal neurons. Remarkably, prenatal treatment of these mice with rapamycin has a positive pharmacological effect on both phenotypes, supporting the therapeutic potential of rapamycin/rapalogs for DS intellectual disability.
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Affiliation(s)
- Jesús David Urbano-Gámez
- Departamento de Fisiología Médica Y Biofísica, Universidad de Sevilla, Av. Sánchez-Pizjuán 4, 41009, Sevilla, Spain.,Instituto de Biomedicina de Sevilla, IBIS/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain
| | - Juan José Casañas
- Departamento de Fisiología Médica Y Biofísica, Universidad de Sevilla, Av. Sánchez-Pizjuán 4, 41009, Sevilla, Spain.,Instituto de Biomedicina de Sevilla, IBIS/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain
| | - Itziar Benito
- Departamento de Fisiología Médica Y Biofísica, Universidad de Sevilla, Av. Sánchez-Pizjuán 4, 41009, Sevilla, Spain.,Instituto de Biomedicina de Sevilla, IBIS/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain.,Servicio de Animalario, Hospital Universitario Virgen Macarena (HUVM), 41009, Sevilla, Spain
| | - María Luz Montesinos
- Departamento de Fisiología Médica Y Biofísica, Universidad de Sevilla, Av. Sánchez-Pizjuán 4, 41009, Sevilla, Spain. .,Instituto de Biomedicina de Sevilla, IBIS/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain.
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40
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Lo LHY, Dong R, Lyu Q, Lai KO. The Protein Arginine Methyltransferase PRMT8 and Substrate G3BP1 Control Rac1-PAK1 Signaling and Actin Cytoskeleton for Dendritic Spine Maturation. Cell Rep 2021; 31:107744. [PMID: 32521269 DOI: 10.1016/j.celrep.2020.107744] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/01/2020] [Accepted: 05/18/2020] [Indexed: 01/25/2023] Open
Abstract
Excitatory synapses of neurons are located on dendritic spines. Spine maturation is essential for the stability of synapses and memory consolidation, and overproduction of the immature filopodia is associated with brain disorders. The structure and function of synapses can be modulated by protein post-translational modification (PTM). Arginine methylation is a major PTM that regulates chromatin structure, transcription, and splicing within the nucleus. Here we find that the protein arginine methyltransferase PRMT8 is present at neuronal synapses and its expression is upregulated in the hippocampus when dendritic spine maturation occurs. Depletion of PRMT8 leads to overabundance of filopodia and mis-localization of excitatory synapses. Mechanistically, PRMT8 promotes dendritic spine morphology through methylation of the dendritic RNA-binding protein G3BP1 and suppression of the Rac1-PAK1 signaling pathway to control synaptic actin dynamics. Our findings unravel arginine methylation as a crucial regulatory mechanism for actin cytoskeleton during synapse development.
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Affiliation(s)
- Louisa Hoi-Ying Lo
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Rui Dong
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Quanwei Lyu
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Kwok-On Lai
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China; State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China.
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Dionne O, Corbin F. An "Omic" Overview of Fragile X Syndrome. BIOLOGY 2021; 10:433. [PMID: 34068266 PMCID: PMC8153138 DOI: 10.3390/biology10050433] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/01/2021] [Accepted: 05/08/2021] [Indexed: 01/16/2023]
Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder associated with a wide range of cognitive, behavioral and medical problems. It arises from the silencing of the fragile X mental retardation 1 (FMR1) gene and, consequently, in the absence of its encoded protein, FMRP (fragile X mental retardation protein). FMRP is a ubiquitously expressed and multifunctional RNA-binding protein, primarily considered as a translational regulator. Pre-clinical studies of the past two decades have therefore focused on this function to relate FMRP's absence to the molecular mechanisms underlying FXS physiopathology. Based on these data, successful pharmacological strategies were developed to rescue fragile X phenotype in animal models. Unfortunately, these results did not translate into humans as clinical trials using same therapeutic approaches did not reach the expected outcomes. These failures highlight the need to put into perspective the different functions of FMRP in order to get a more comprehensive understanding of FXS pathophysiology. This work presents a review of FMRP's involvement on noteworthy molecular mechanisms that may ultimately contribute to various biochemical alterations composing the fragile X phenotype.
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Affiliation(s)
- Olivier Dionne
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke and Centre de Recherche du CHUS, CIUSSS de l’Estrie-CHUS, Sherbrooke, QC J1H 5H4, Canada;
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42
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Khayachi A, Schorova L, Alda M, Rouleau GA, Milnerwood AJ. Posttranslational modifications & lithium's therapeutic effect-Potential biomarkers for clinical responses in psychiatric & neurodegenerative disorders. Neurosci Biobehav Rev 2021; 127:424-445. [PMID: 33971223 DOI: 10.1016/j.neubiorev.2021.05.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 03/14/2021] [Accepted: 05/03/2021] [Indexed: 01/03/2023]
Abstract
Several neurodegenerative diseases and neuropsychiatric disorders display aberrant posttranslational modifications (PTMs) of one, or many, proteins. Lithium treatment has been used for mood stabilization for many decades, and is highly effective for large subsets of patients with diverse neurological conditions. However, the differential effectiveness and mode of action are not fully understood. In recent years, studies have shown that lithium alters several protein PTMs, altering their function, and consequently neuronal physiology. The impetus for this review is to outline the links between lithium's therapeutic mode of action and PTM homeostasis. We first provide an overview of the principal PTMs affected by lithium. We then describe several neuropsychiatric disorders in which PTMs have been implicated as pathogenic. For each of these conditions, we discuss lithium's clinical use and explore the putative mechanism of how it restores PTM homeostasis, and thereby cellular physiology. Evidence suggests that determining specific PTM patterns could be a promising strategy to develop biomarkers for disease and lithium responsiveness.
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Affiliation(s)
- A Khayachi
- Montreal Neurological Institute, Department of Neurology & Neurosurgery, McGill University, Montréal, Quebec, Canada.
| | - L Schorova
- McGill University Health Center Research Institute, Montréal, Quebec, Canada
| | - M Alda
- Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - G A Rouleau
- Montreal Neurological Institute, Department of Neurology & Neurosurgery, McGill University, Montréal, Quebec, Canada; Department of Human Genetics, McGill University, Montréal, Quebec, Canada.
| | - A J Milnerwood
- Montreal Neurological Institute, Department of Neurology & Neurosurgery, McGill University, Montréal, Quebec, Canada.
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Altered Phosphorylation of the Proteasome Subunit Rpt6 Has Minimal Impact on Synaptic Plasticity and Learning. eNeuro 2021; 8:ENEURO.0073-20.2021. [PMID: 33658307 PMCID: PMC8116113 DOI: 10.1523/eneuro.0073-20.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 01/13/2021] [Accepted: 01/27/2021] [Indexed: 11/21/2022] Open
Abstract
Dynamic control of protein degradation via the ubiquitin proteasome system (UPS) is thought to play a crucial role in neuronal function and synaptic plasticity. The proteasome subunit Rpt6, an AAA ATPase subunit of the 19S regulatory particle (RP), has emerged as an important site for regulation of 26S proteasome function in neurons. Phosphorylation of Rpt6 on serine 120 (S120) can stimulate the catalytic rate of substrate degradation by the 26S proteasome and this site is targeted by the plasticity-related kinase Ca2+/calmodulin-dependent kinase II (CaMKII), making it an attractive candidate for regulation of proteasome function in neurons. Several in vitro studies have shown that altered Rpt6 S120 phosphorylation can affect the structure and function of synapses. To evaluate the importance of Rpt6 S120 phosphorylation in vivo, we created two mouse models which feature mutations at S120 that block or mimic phosphorylation at this site. We find that peptidase and ATPase activities are upregulated in the phospho-mimetic mutant and downregulated in the phospho-dead mutant [S120 mutated to aspartic acid (S120D) or alanine (S120A), respectively]. Surprisingly, these mutations had no effect on basal synaptic transmission, long-term potentiation (LTP), and dendritic spine dynamics and density in the hippocampus. Furthermore, these mutants displayed no deficits in cued and contextual fear memory. Thus, in a mouse model that blocks or mimics phosphorylation at this site, either compensatory mechanisms negate these effects, or small variations in proteasome activity are not enough to induce significant changes in synaptic structure, plasticity, or behavior.
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Cell-type-specific profiling of human cellular models of fragile X syndrome reveal PI3K-dependent defects in translation and neurogenesis. Cell Rep 2021; 35:108991. [PMID: 33852833 PMCID: PMC8133829 DOI: 10.1016/j.celrep.2021.108991] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/08/2021] [Accepted: 03/23/2021] [Indexed: 02/06/2023] Open
Abstract
Transcriptional silencing of the FMR1 gene in fragile X syndrome (FXS) leads to the loss of the RNA-binding protein FMRP. In addition to regulating mRNA translation and protein synthesis, emerging evidence suggests that FMRP acts to coordinate proliferation and differentiation during early neural development. However, whether loss of FMRP-mediated translational control is related to impaired cell fate specification in the developing human brain remains unknown. Here, we use human patient induced pluripotent stem cell (iPSC)-derived neural progenitor cells and organoids to model neurogenesis in FXS. We developed a high-throughput, in vitro assay that allows for the simultaneous quantification of protein synthesis and proliferation within defined neural subpopulations. We demonstrate that abnormal protein synthesis in FXS is coupled to altered cellular decisions to favor proliferative over neurogenic cell fates during early development. Furthermore, pharmacologic inhibition of elevated phosphoinositide 3-kinase (PI3K) signaling corrects both excess protein synthesis and cell proliferation in a subset of patient neural cells. Raj et al. developed a multiparametric assay to measure cellular and molecular phenotypes during neurogenesis in fragile X syndrome iPSC-derived neural cells. Relative to controls, FXS patient cultures have more proliferative cells with increased protein synthesis. Defects in cell fate acquisition can be normalized by inhibiting overactive PI3K signaling.
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Yang W, Zhou X, Ryazanov AG, Ma T. Suppression of the kinase for elongation factor 2 alleviates mGluR-LTD impairments in a mouse model of Alzheimer's disease. Neurobiol Aging 2021; 98:225-230. [PMID: 33341653 PMCID: PMC8201868 DOI: 10.1016/j.neurobiolaging.2020.11.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/05/2020] [Accepted: 11/22/2020] [Indexed: 01/06/2023]
Abstract
Impaired mRNA translation (protein synthesis) is linked to Alzheimer's disease (AD) pathophysiology. Recent studies revealed the role of increased phosphorylation of eukaryotic elongation factor 2 (eEF2) in AD-associated cognitive deficits. Phosphorylation of eEF2 (at the Thr56 site) by its only known kinase eEF2K leads to inhibition of general protein synthesis. AD is considered as a disease of "synaptic failure" characterized by impairments of synaptic plasticity, including long-term potentiation (LTP) and long-term depression (LTD). Deficiency of metabotropic glutamate receptor 5-dependent LTD (mGluR-LTD) is indicated in cognitive syndromes associated with various neurological disorders, including AD, but the molecular signaling mechanisms underlying the mGluR-LTD dysregulation in AD remain unclear. In this brief communication, we report genetic repression of eEF2K in aged APP/PS1 AD model mice prevented AD-associated hippocampal mGluR-LTD deficits. Using a pharmacological approach, we further observed that impairments of mGluR-LTD in APP/PS1 mice were rescued by treating hippocampal slices with a small molecule eEF2K antagonist NH125. Our findings, taken together, suggest a critical role of abnormal protein synthesis dysregulation at the elongation phase in AD-associated mGluR-LTD failure, thus providing insights into a mechanistic understanding of synaptic impairments in AD and other related dementia syndromes.
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Affiliation(s)
- Wenzhong Yang
- Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Xueyan Zhou
- Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Alexey G Ryazanov
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA
| | - Tao Ma
- Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA; Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA; Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
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46
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Dissociation of functional and structural plasticity of dendritic spines during NMDAR and mGluR-dependent long-term synaptic depression in wild-type and fragile X model mice. Mol Psychiatry 2021; 26:4652-4669. [PMID: 32606374 PMCID: PMC8095717 DOI: 10.1038/s41380-020-0821-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 06/03/2020] [Accepted: 06/12/2020] [Indexed: 12/14/2022]
Abstract
Many neurodevelopmental disorders are characterized by impaired functional synaptic plasticity and abnormal dendritic spine morphology, but little is known about how these are related. Previous work in the Fmr1-/y mouse model of fragile X (FX) suggests that increased constitutive dendritic protein synthesis yields exaggerated mGluR5-dependent long-term synaptic depression (LTD) in area CA1 of the hippocampus, but an effect on spine structural plasticity remains to be determined. In the current study, we used simultaneous electrophysiology and time-lapse two photon imaging to examine how spines change their structure during LTD induced by activation of mGluRs or NMDA receptors (NMDARs), and how this plasticity is altered in Fmr1-/y mice. We were surprised to find that mGluR activation causes LTD and AMPA receptor internalization, but no spine shrinkage in either wildtype or Fmr1-/y mice. In contrast, NMDAR activation caused spine shrinkage as well as LTD in both genotypes. Spine shrinkage was initiated by non-ionotropic (metabotropic) signaling through NMDARs, and in wild-type mice this structural plasticity required activation of mTORC1 and new protein synthesis. In striking contrast, NMDA-induced spine plasticity in Fmr1-/y mice was no longer dependent on acute activation of mTORC1 or de novo protein synthesis. These findings reveal that the structural consequences of mGluR and metabotropic NMDAR activation differ, and that a brake on spine structural plasticity, normally provided by mTORC1 regulation of protein synthesis, is absent in FX. Increased constitutive protein synthesis in FX appears to modify functional and structural plasticity induced through different glutamate receptors.
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Shukla T, de la Peña JB, Perish JM, Ploski JE, Stumpf CR, Webster KR, Thorn CA, Campbell ZT. A Highly Selective MNK Inhibitor Rescues Deficits Associated with Fragile X Syndrome in Mice. Neurotherapeutics 2021; 18:624-639. [PMID: 33006091 PMCID: PMC8116363 DOI: 10.1007/s13311-020-00932-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2020] [Indexed: 12/22/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common inherited source of intellectual disability in humans. FXS is caused by mutations that trigger epigenetic silencing of the Fmr1 gene. Loss of Fmr1 results in increased activity of the mitogen-activated protein kinase (MAPK) pathway. An important downstream consequence is activation of the mitogen-activated protein kinase interacting protein kinase (MNK). MNK phosphorylates the mRNA cap-binding protein, eukaryotic initiation factor 4E (eIF4E). Excessive phosphorylation of eIF4E has been directly implicated in the cognitive and behavioral deficits associated with FXS. Pharmacological reduction of eIF4E phosphorylation is one potential strategy for FXS treatment. We demonstrate that systemic dosing of a highly specific, orally available MNK inhibitor, eFT508, attenuates numerous deficits associated with loss of Fmr1 in mice. eFT508 resolves a range of phenotypic abnormalities associated with FXS including macroorchidism, aberrant spinogenesis, and alterations in synaptic plasticity. Key behavioral deficits related to anxiety, social interaction, obsessive and repetitive activities, and object recognition are ameliorated by eFT508. Collectively, this work establishes eFT508 as a potential means to reverse deficits associated with FXS.
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Affiliation(s)
- Tarjani Shukla
- Department of Biological Sciences, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
- Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX, 75080, USA
| | - June Bryan de la Peña
- Department of Biological Sciences, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
- Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX, 75080, USA
| | - John M Perish
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Jonathan E Ploski
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, 75080, USA
| | | | | | - Catherine A Thorn
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Zachary T Campbell
- Department of Biological Sciences, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA.
- Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX, 75080, USA.
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Champigny C, Morin-Parent F, Bellehumeur-Lefebvre L, Çaku A, Lepage JF, Corbin F. Combining Lovastatin and Minocycline for the Treatment of Fragile X Syndrome: Results From the LovaMiX Clinical Trial. Front Psychiatry 2021; 12:762967. [PMID: 35058813 PMCID: PMC8763805 DOI: 10.3389/fpsyt.2021.762967] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/29/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Limited success of previous clinical trials for Fragile X syndrome (FXS) has led researchers to consider combining different drugs to correct the pleiotropic consequences caused by the absence of the Fragile X mental retardation protein (FMRP). Here, we report the results of the LovaMiX clinical trial, the first trial for FXS combining two disease-modifying drugs, lovastatin, and minocycline, which have both shown positive effects when used independently. Aim: The main goals of the study were to assess the safety and efficacy of a treatment combining lovastatin and minocycline for patients with FXS. Design: Pilot Phase II open-label clinical trial. Patients with a molecular diagnostic of FXS were first randomized to receive, in two-step titration either lovastatin or minocycline for 8 weeks, followed by dual treatment with lovastatin 40 mg and minocycline 100 mg for 2 weeks. Clinical assessments were performed at the beginning, after 8 weeks of monotherapy, and at week 20 (12 weeks of combined therapy). Outcome Measures: The primary outcome measure was the Aberrant Behavior Checklist-Community (ABC-C) global score. Secondary outcome measures included subscales of the FXS specific ABC-C (ABC-CFX), the Anxiety, Depression, and Mood Scale (ADAMS), the Social Responsiveness Scale (SRS), the Behavior Rating Inventory of Executive Functions (BRIEF), and the Vineland Adaptive Behavior Scale second edition (VABS-II). Results: Twenty-one individuals out of 22 completed the trial. There were no serious adverse events related to the use of either drugs alone or in combination, suggesting good tolerability and safety profile of the combined therapy. Significant improvement was noted on the primary outcome measure with a 40% decrease on ABC-C global score with the combined therapy. Several outcome measures also showed significance. Conclusion: The combination of lovastatin and minocycline is safe in patients for FXS individuals and appears to improve several elements of the behavior. These results set the stage for a larger, placebo-controlled double-blind clinical trial to confirm the beneficial effects of the combined therapy.
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Affiliation(s)
- Camille Champigny
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada.,Centre de Recherche du CHUS (CRCHUS), Sherbrooke, QC, Canada
| | | | - Laurence Bellehumeur-Lefebvre
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada.,Centre de Recherche du CHUS (CRCHUS), Sherbrooke, QC, Canada
| | - Artuela Çaku
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada.,Centre de Recherche du CHUS (CRCHUS), Sherbrooke, QC, Canada
| | - Jean-François Lepage
- Centre de Recherche du CHUS (CRCHUS), Sherbrooke, QC, Canada.,Faculty of Medicine and Health Sciences, Department of Pediatrics, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - François Corbin
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada.,Centre de Recherche du CHUS (CRCHUS), Sherbrooke, QC, Canada
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49
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Dhar GA, Saha S, Mitra P, Nag Chaudhuri R. DNA methylation and regulation of gene expression: Guardian of our health. THE NUCLEUS 2021; 64:259-270. [PMID: 34421129 PMCID: PMC8366481 DOI: 10.1007/s13237-021-00367-y] [Citation(s) in RCA: 103] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 07/30/2021] [Indexed: 02/07/2023] Open
Abstract
One of the most critical epigenetic signatures present in the genome of higher eukaryotes is the methylation of DNA at the C-5 position of the cytosine ring. Based on the sites of DNA methylation in a locus, it can serve as a repressive or activation mark for gene expression. In a crosstalk with histone modifiers, DNA methylation can consequently either inhibit binding of the transcription machinery or generate a landscape conducive for transcription. During developmental phases, the DNA methylation pattern in the genome undergoes alterations as a result of regulated balance between de novo DNA methylation and demethylation. Resultantly, differentiated cells inherit a unique DNA methylation pattern that fine tunes tissue-specific gene expression. Although apparently a stable epigenetic mark, DNA methylation is actually labile and is a complex reflection of interaction between epigenome, genome and environmental factors prior to birth and during progression of life. Recent findings indicate that levels of DNA methylation in an individual is a dynamic outcome, strongly influenced by the dietary environment during germ cell formation, embryogenesis and post birth exposures. Loss of balances in DNA methylation during developmental stages may result in imprinting disorders, while at any later stage may lead to increased predisposition to various diseases and abnormalities. This review aims to provide an outline of how our epigenome is uniquely guided by our lifetime of experiences beginning in the womb and how understanding it better holds future possibilities of improvised clinical applications.
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Affiliation(s)
- Gaurab Aditya Dhar
- grid.59056.3f0000 0001 0664 9773Department of Biotechnology, St. Xavier’s College, 30 Mother Teresa Sarani, Kolkata, 700016 India
| | - Shagnik Saha
- grid.59056.3f0000 0001 0664 9773Department of Biotechnology, St. Xavier’s College, 30 Mother Teresa Sarani, Kolkata, 700016 India
| | - Parama Mitra
- grid.59056.3f0000 0001 0664 9773Department of Biotechnology, St. Xavier’s College, 30 Mother Teresa Sarani, Kolkata, 700016 India
| | - Ronita Nag Chaudhuri
- grid.59056.3f0000 0001 0664 9773Department of Biotechnology, St. Xavier’s College, 30 Mother Teresa Sarani, Kolkata, 700016 India
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50
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Briševac D, Scholz R, Du D, Elagabani MN, Köhr G, Kornau HC. The small GTPase Arf6 is dysregulated in a mouse model for fragile X syndrome. J Neurochem 2020; 157:666-683. [PMID: 33125726 DOI: 10.1111/jnc.15230] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 10/09/2020] [Accepted: 10/27/2020] [Indexed: 11/29/2022]
Abstract
Fragile X syndrome (FXS), the most common inherited cause of intellectual disability, results from silencing of the fragile X mental retardation gene 1 (FMR1). The analyses of FXS patients' brain autopsies revealed an increased density of immature dendritic spines in cortical areas. We hypothesize that the small GTPase Arf6, an actin regulator critical for the development of glutamatergic synapses and dendritic spines, is implicated in FXS. Here, we determined the fraction of active, GTP-bound Arf6 in cortical neuron cultures and synaptoneurosomes from Fmr1 knockout mice, measured actin polymerization in neurons expressing Arf6 mutants with variant GTP- or GDP-binding properties, and recorded hippocampal long-term depression induced by metabotropic glutamate receptors (mGluR-LTD) in acute brain slices. We detected a persistently elevated Arf6 activity, a loss of Arf6 sensitivity to synaptic stimulation and an increased Arf6-dependent dendritic actin polymerization in mature Fmr1 knockout neurons. Similar imbalances in Arf6-GTP levels and actin filament assembly were caused in wild-type neurons by RNAi-mediated depletion of the postsynaptic Arf6 guanylate exchange factors IQSEC1 (BRAG2) or IQSEC2 (BRAG1). Targeted deletion of Iqsec1 in hippocampal neurons of 3-week-old mice interfered with mGluR-LTD in wild-type, but not in Fmr1 knockout mice. Collectively, these data suggest an aberrant Arf6 regulation in Fmr1 knockout neurons with consequences for the actin cytoskeleton, spine morphology, and synaptic plasticity. Moreover, FXS and syndromes caused by genetic variants in IQSEC1 and IQSEC2 share intellectual disabilities and developmental delay as main symptoms. Therefore, dysregulation of Arf6 may contribute to the cognitive impairment in FXS.
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Affiliation(s)
- Dušica Briševac
- Neuroscience Research Center (NWFZ), Charité - Universitätsmedizin Berlin, Berlin, Germany.,Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Ralf Scholz
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Dan Du
- Central Institute of Mental Health, Mannheim Center for Translational Neuroscience, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | | | - Georg Köhr
- Central Institute of Mental Health, Mannheim Center for Translational Neuroscience, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.,Department of Neurophysiology, Mannheim Center for Translational Neuroscience, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Hans-Christian Kornau
- Neuroscience Research Center (NWFZ), Charité - Universitätsmedizin Berlin, Berlin, Germany.,Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany.,German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany
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