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van der Heijden ME. Converging and Diverging Cerebellar Pathways for Motor and Social Behaviors in Mice. CEREBELLUM (LONDON, ENGLAND) 2024:10.1007/s12311-024-01706-w. [PMID: 38780757 DOI: 10.1007/s12311-024-01706-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/17/2024] [Indexed: 05/25/2024]
Abstract
Evidence from clinical and preclinical studies has shown that the cerebellum contributes to cognitive functions, including social behaviors. Now that the cerebellum's role in a wider range of behaviors has been confirmed, the question arises whether the cerebellum contributes to social behaviors via the same mechanisms with which it modulates movements. This review seeks to answer whether the cerebellum guides motor and social behaviors through identical pathways. It focuses on studies in which cerebellar cells, synapses, or genes are manipulated in a cell-type specific manner followed by testing of the effects on social and motor behaviors. These studies show that both anatomically restricted and cerebellar cortex-wide manipulations can lead to social impairments without abnormal motor control, and vice versa. These studies suggest that the cerebellum employs different cellular, synaptic, and molecular pathways for social and motor behaviors. Future studies warrant a focus on the diverging mechanisms by which the cerebellum contributes to a wide range of neural functions.
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Affiliation(s)
- Meike E van der Heijden
- Fralin Biomedical Research Institute, Virginia Tech Carilion, Roanoke, VA, USA.
- Center for Neurobiology Research, Virginia Tech Carilion, Roanoke, VA, USA.
- School of Neuroscience, Virginia Tech, Blacksburg, VA, USA.
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Nair D, Diaz-Rosado A, Varella-Branco E, Ramos I, Black A, Angireddy R, Park J, Murali S, Yoon A, Ciesielski B, O’Brien WT, Passos-Bueno MR, Bhoj E. Heterozygous variants in TBCK cause a mild neurologic syndrome in humans and mice. Am J Med Genet A 2023; 191:2508-2517. [PMID: 37353954 PMCID: PMC10524953 DOI: 10.1002/ajmg.a.63320] [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: 12/23/2022] [Revised: 05/15/2023] [Accepted: 05/26/2023] [Indexed: 06/25/2023]
Abstract
TBCK-related encephalopathy is a rare pediatric neurodegenerative disorder caused by biallelic loss-of-function variants in the TBCK gene. After receiving anecdotal reports of neurologic phenotypes in both human and mouse TBCK heterozygotes, we quantified if TBCK haploinsufficiency causes a phenotype in mice and humans. Using the tbck+/- mouse model, we performed a battery of behavioral assays and mTOR pathway analysis to investigate potential alterations in neurophysiology. We conducted as well a phenome-wide association study (PheWAS) analysis in a large adult biobank to determine the presence of potential phenotypes associated to this variant. The tbck+/- mouse model demonstrates a reduction of exploratory behavior in animals with significant sex and genotype interactions. The concurrent PheWAS analysis of 10,900 unrelated individuals showed that patients with one copy of a TBCK loss-of-function allele had a significantly higher rate of acquired toe and foot deformities, likely indicative of a mild peripheral neuropathy phenotype. This study presents an example of what may be the underappreciated occurrence of mild neurogenic symptoms in heterozygote individuals of recessive neurogenetic syndromes.
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Affiliation(s)
- Divya Nair
- Department of Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104 USA
| | - Abdias Diaz-Rosado
- Department of Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104 USA
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Elisa Varella-Branco
- Centro de Estudos do Genoma Humano e Células-Tronco, Universidade de São Paulo, São Paulo, Brazil
| | - Igor Ramos
- Centro de Estudos do Genoma Humano e Células-Tronco, Universidade de São Paulo, São Paulo, Brazil
| | - Aaron Black
- Department of Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104 USA
| | - Rajesh Angireddy
- Department of Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104 USA
| | - Joseph Park
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Svathi Murali
- Department of Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104 USA
- Department of Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Andrew Yoon
- Department of Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104 USA
| | - Brianna Ciesielski
- ITMAT, University of Pennsylvania, School of Medicine, Philadelphia, PA, 19104 USA
| | - W. Timothy O’Brien
- ITMAT, University of Pennsylvania, School of Medicine, Philadelphia, PA, 19104 USA
| | | | - Elizabeth Bhoj
- Department of Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104 USA
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Muthaffar OY, Jan MMS, Alyazidi AS, Alotibi TK, Alsulami EA. Insight into Genetic Mutations of SZT2: Is It a Syndrome? Biomedicines 2023; 11:2402. [PMID: 37760843 PMCID: PMC10525120 DOI: 10.3390/biomedicines11092402] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 08/21/2023] [Accepted: 08/23/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND The seizure threshold 2 (SZT2) gene encodes a protein of unknown function, which is widely expressed, confers a low seizure threshold, and enhances epileptogenesis. It also comprises the KICSTOR protein complex, which inhibits the mTORC1 pathway. A pathogenic variant in the SZT2 gene could result in hyperactive mTORC1 signaling, which can lead to several neurological disorders. AIM OF THE STUDY To review every reported case and present two novel cases to expand the current knowledge and understanding of the mutation. METHODS Whole exome sequencing (WES) was used to identify the novel cases and present their clinical and radiological findings. A detailed revision of the literature was conducted to illustrate and compare findings. The clinical, genetical, neuroimaging, and electrophysiological data were extracted. RESULTS The study included 16 female patients and 13 male patients in addition to the 2 novel male cases. Eighteen patients had heterozygous mutations; others were homozygous. The majority presented with facial dysmorphism (n = 22). Seizures were noted as the predominant hallmark (n = 26). Developmental delay and hypotonia were reported in 27 and 15 patients, respectively. The majority of patients had multifocal epileptiform discharges on the electroencephalogram (EEG) and short and thick corpus callosum on the magnetic resonance imaging (MRI). CONCLUSION Several promising features are becoming strongly linked to patients with SZT2 mutations. High variability among the cases was observed. Developmental delay and facial dysmorphism can be investigated as potential hallmarks; aiding clinicians in diagnosing the condition and optimizing management plans.
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Affiliation(s)
- Osama Y. Muthaffar
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (O.Y.M.); (M.M.S.J.)
| | - Mohammed M. S. Jan
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (O.Y.M.); (M.M.S.J.)
| | - Anas S. Alyazidi
- Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (T.K.A.); (E.A.A.)
| | - Taif K. Alotibi
- Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (T.K.A.); (E.A.A.)
| | - Eman A. Alsulami
- Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (T.K.A.); (E.A.A.)
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The Cerebellum in Niemann-Pick C1 Disease: Mouse Versus Man. CEREBELLUM (LONDON, ENGLAND) 2023; 22:102-119. [PMID: 35040097 DOI: 10.1007/s12311-021-01347-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/17/2021] [Indexed: 02/01/2023]
Abstract
Selective neuronal vulnerability is common to most degenerative disorders, including Niemann-Pick C (NPC), a rare genetic disease with altered intracellular trafficking of cholesterol. Purkinje cell dysfunction and loss are responsible for cerebellar ataxia, which is among the prevailing neurological signs of the NPC disease. In this review, we focus on some questions that are still unresolved. First, we frame the cerebellar vulnerability in the context of the extended postnatal time length by which the development of this structure is completed in mammals. In line with this thought, the much later development of cerebellar symptoms in humans is due to the later development and/or maturation of the cerebellum. Hence, the occurrence of developmental events under a protracted condition of defective intracellular cholesterol mobilization hits the functional maturation of the various cell types generating the ground of increased vulnerability. This is particularly consistent with the high cholesterol demand required for cell proliferation, migration, differentiation, and synapse formation/remodeling. Other major questions we address are why the progression of Purkinje cells loss is always from the anterior to the posterior lobes and why cerebellar defects persist in the mouse model even when genetic manipulations can lead to nearly normal survival.
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Sun Y, Hu X, Qiu D, Zhang Z, Lei L. rDNA Transcription in Developmental Diseases and Stem Cells. Stem Cell Rev Rep 2023; 19:839-852. [PMID: 36633782 DOI: 10.1007/s12015-023-10504-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/01/2023] [Indexed: 01/13/2023]
Abstract
As the first and rate-limiting step in ribosome biogenesis, rDNA transcription undergoes significant dynamic changes during cell pluripotency alteration. Over the past decades, rDNA activity has demonstrated dynamic changes, but most people view it as passive compliance with cellular needs. The evidence for rDNA transcriptional activity determining stem cell pluripotency is growing as research advances, resulting in the arrest of embryonic development and impairment of stem cell lines stemness by rDNA transcription inhibition. The exact mechanism by which rDNA activation influences pluripotency remains unknown. The first objective of this opinion article is to describe rDNA changes in the pathological and physiological course of life, including developmental diseases, tumor genesis, and stem cell differentiation. After that, we propose three hypotheses regarding rDNA regulation of pluripotency: 1) Specialized ribosomes synthesized from rDNA variant, 2) Nucleolar stress induced by the drop of rDNA transcription, 3) Interchromosomal interactions between rDNA and other genes. The pluripotency regulatory center is expected to focus strongly on rDNA. A small molecule inhibitor of rDNA is used to treat tumors caused by abnormal pluripotency activation. By understanding how rDNA regulates pluripotency, we hope to treat developmental diseases and safely apply somatic cell reprogramming in clinical settings.
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Affiliation(s)
- Yuchen Sun
- Department of Histology and Embryology, Basic Medical Science College, Harbin Medical University, 194 Xuefu Rd, Nangang District, Harbin, Heilongjiang Province, People's Republic of China, 150081
| | - Xinglin Hu
- Department of Histology and Embryology, Basic Medical Science College, Harbin Medical University, 194 Xuefu Rd, Nangang District, Harbin, Heilongjiang Province, People's Republic of China, 150081
| | - Dan Qiu
- Department of Histology and Embryology, Basic Medical Science College, Harbin Medical University, 194 Xuefu Rd, Nangang District, Harbin, Heilongjiang Province, People's Republic of China, 150081
| | - Zhijing Zhang
- Department of Histology and Embryology, Basic Medical Science College, Harbin Medical University, 194 Xuefu Rd, Nangang District, Harbin, Heilongjiang Province, People's Republic of China, 150081
| | - Lei Lei
- Department of Histology and Embryology, Basic Medical Science College, Harbin Medical University, 194 Xuefu Rd, Nangang District, Harbin, Heilongjiang Province, People's Republic of China, 150081.
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GPRC6A Mediates Glucose and Amino Acid Homeostasis in Mice. Metabolites 2022; 12:metabo12080740. [PMID: 36005612 PMCID: PMC9415337 DOI: 10.3390/metabo12080740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/03/2022] [Accepted: 08/08/2022] [Indexed: 11/29/2022] Open
Abstract
GPRC6A, an important member of the G-protein-coupled receptor superfamily, has been widely studied in body health maintenance and related diseases. However, it is still controversial whether GPRC6A plays a vital role in glucose homeostasis, and the role of GPRC6A on amino acid homeostasis has not been reported. In this study, GPRC6A was knocked out in C57BL6 mice, and we found that GPRC6A plays an important role in the glucose metabolism, mainly affecting the glucose clearance capacity and gluconeogenesis in mice. GPRC6A plays an important role in maintaining amino acid homeostasis under dietary restrictions, and this may be realized by participating in the regulation of autophagy. Since a large amount of amino acid is lost from urine in aged GPRC6A−/− mice, it is possible that GPRC6A regulates amino acid homeostasis by affecting the integrity of tissue structure. GPRC6A is involved in the regulation of mTORC1 activation but is not necessary for mTORC1 activation under sufficient nutritional supply. In the absence of exogenous amino acids, the loss of GPRC6A induces the GCN2 pathway activation and excessive autophagy of cells, leading to the overactivation of mTORC1, which may be detrimental to body health and cell survival. In summary, this study provides a theoretical and experimental basis for the metabolic process of GPRC6A in body growth and health.
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Schrötter S, Yuskaitis CJ, MacArthur MR, Mitchell SJ, Hosios AM, Osipovich M, Torrence ME, Mitchell JR, Hoxhaj G, Sahin M, Manning BD. The non-essential TSC complex component TBC1D7 restricts tissue mTORC1 signaling and brain and neuron growth. Cell Rep 2022; 39:110824. [PMID: 35584673 PMCID: PMC9175135 DOI: 10.1016/j.celrep.2022.110824] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/21/2022] [Accepted: 04/23/2022] [Indexed: 11/16/2022] Open
Abstract
The tuberous sclerosis complex (TSC) 1 and 2 proteins associate with TBC1D7 to form the TSC complex, which is an essential suppressor of mTOR complex 1 (mTORC1), a ubiquitous driver of cell and tissue growth. Loss-of-function mutations in TSC1 or TSC2, but not TBC1D7, give rise to TSC, a pleiotropic disorder with aberrant activation of mTORC1 in various tissues. Here, we characterize mice with genetic deletion of Tbc1d7, which are viable with normal growth and development. Consistent with partial loss of function of the TSC complex, Tbc1d7 knockout (KO) mice display variable increases in tissue mTORC1 signaling with increased muscle fiber size but with strength and motor defects. Their most pronounced phenotype is brain overgrowth due to thickening of the cerebral cortex, with enhanced neuron-intrinsic mTORC1 signaling and growth. Thus, TBC1D7 is required for full TSC complex function in tissues, and the brain is particularly sensitive to its growth-suppressing activities.
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Affiliation(s)
- Sandra Schrötter
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Christopher J Yuskaitis
- Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Michael R MacArthur
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Sarah J Mitchell
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Aaron M Hosios
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Maria Osipovich
- Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Margaret E Torrence
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - James R Mitchell
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Gerta Hoxhaj
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Mustafa Sahin
- Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Brendan D Manning
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Cell Biology, Harvard Medical School, Boston, MA, USA.
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Abstract
BK channelopathy has been increasingly implicated in diverse neurological disorders, including epilepsy and movement, cognitive, and neurodevelopmental disorders. However, precision medicine to treat BK channelopathy is lacking. We characterized a mouse model carrying a gain-of-function BK channelopathy D434G from a large family of patients with absence epilepsy and paroxysmal dyskinesia. The BK-D434G mice manifest the clinical features of absence seizures and exhibit severe locomotor defects including involuntary dyskinesia-like behavior. Pharmacological inhibition of BK channels suppresses neuronal hyperactivity and mitigates absence seizure and the locomotor defects. The BK-D434G mice thus serve as a model to understand the pathogenic mechanisms of absence epilepsy and dyskinesia. Our study also suggests that BK inhibition is a promising strategy for treating BK gain-of-function channelopathy. A growing number of gain-of-function (GOF) BK channelopathies have been identified in patients with epilepsy and movement disorders. Nevertheless, the underlying pathophysiology and corresponding therapeutics remain obscure. Here, we utilized a knock-in mouse model carrying human BK-D434G channelopathy to investigate the neuronal mechanism of BK GOF in the pathogenesis of epilepsy and dyskinesia. The BK-D434G mice manifest the clinical features of absence epilepsy and exhibit severe motor deficits and dyskinesia-like behaviors. The cortical pyramidal neurons and cerebellar Purkinje cells from the BK-D434G mice show hyperexcitability, which likely contributes to the pathogenesis of absence seizures and paroxysmal dyskinesia. A BK channel blocker, paxilline, potently suppresses BK-D434G–induced hyperexcitability and effectively mitigates absence seizures and locomotor deficits in mice. Our study thus uncovered a neuronal mechanism of BK GOF in absence epilepsy and dyskinesia. Our findings also suggest that BK inhibition is a promising therapeutic strategy for mitigating BK GOF-induced neurological disorders.
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Ellul P, Rosenzwajg M, Peyre H, Fourcade G, Mariotti-Ferrandiz E, Trebossen V, Klatzmann D, Delorme R. Regulatory T lymphocytes/Th17 lymphocytes imbalance in autism spectrum disorders: evidence from a meta-analysis. Mol Autism 2021; 12:68. [PMID: 34641964 PMCID: PMC8507168 DOI: 10.1186/s13229-021-00472-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 09/29/2021] [Indexed: 12/27/2022] Open
Abstract
Background Immune system dysfunction has been proposed to play a critical role in the pathophysiology of autism spectrum disorders (ASD). Conflicting reports of lymphocyte subpopulation abnormalities have been described in numerous studies of patients with ASD. To better define lymphocytes abnormalities in ASD, we performed a meta-analysis of the lymphocyte profiles from subjects with ASD. Methods We used the PRISMA recommendations to query PubMed, Embase, PsychoINFO, BIOSIS, Science Direct, Cochrane CENTRAL, and Clinicaltrials.gov for terms related to clinical diagnosis of ASD and to lymphocytes’ populations. We selected studies exploring lymphocyte subpopulations in children with ASD. The search protocol has been registered in the international Prospective Register of Systematic Reviews (CRD42019121473). Results We selected 13 studies gathering 388 ASD patients and 326 healthy controls. A significant decrease in the CD4+ lymphocyte was found in ASD patients compared to controls [− 1.51 (95% CI − 2.99; − 0.04) p = 0.04] (I2 = 96% [95% CI 94.6, 97.7], p < 0.01). No significant difference was found for the CD8+ T, B and natural killer lymphocytes. Considering the CD4+ subpopulation, there was a significant decrease in regulatory T lymphocytes (Tregs) in ASD patients (n = 114) compared to controls (n = 107) [− 3.09 (95% CI − 4.41; − 1.76) p = 0.0001]; (I2 = 90.9%, [95% CI 76.2, 96.5], p < 0.0001) associated with an increase oin the Th17 lymphocytes (ASD; n = 147 controls; n = 128) [2.23 (95% CI 0.79; 3.66) p = 0,002] (I2 = 95.1% [95% CI 90.4, 97.5], p < 0.0001). Limitations Several factors inducing heterogeneity should be considered. First, differences in the staining method may be responsible for a part in the heterogeneity of results. Second, ASD population is also by itself heterogeneous, underlying the need of studying sub-groups that are more homogeneous. Conclusion Our meta-analysis indicates defects in CD4+ lymphocytes, specifically decrease oin Tregs and increase in Th17 in ASD patients and supports the development of targeted immunotherapies in the field of ASD. Supplementary Information The online version contains supplementary material available at 10.1186/s13229-021-00472-4.
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Affiliation(s)
- Pierre Ellul
- AP-HP (Assistance Publique-Hôpitaux de Paris), Robert Debré Hospital, Child and Adolescent Psychiatry Department, Paris University, 48 Boulevard Sérurier, 75019, Paris, France. .,INSERM, Immunology-Immunopathology-Immunotherapy (i3), Sorbonne Université, Paris, France.
| | - Michelle Rosenzwajg
- INSERM, Immunology-Immunopathology-Immunotherapy (i3), Sorbonne Université, Paris, France.,AP-HP, Hôpital Pitié-Salpêtrière, Biotherapy (CIC-BTi), Paris, France
| | - Hugo Peyre
- AP-HP (Assistance Publique-Hôpitaux de Paris), Robert Debré Hospital, Child and Adolescent Psychiatry Department, Paris University, 48 Boulevard Sérurier, 75019, Paris, France.,Robert Debré Hospital, UMR 1141, NeuroDiderot Inserm - Paris University, Paris, France
| | - Gwladys Fourcade
- INSERM, Immunology-Immunopathology-Immunotherapy (i3), Sorbonne Université, Paris, France
| | | | - Vincent Trebossen
- AP-HP (Assistance Publique-Hôpitaux de Paris), Robert Debré Hospital, Child and Adolescent Psychiatry Department, Paris University, 48 Boulevard Sérurier, 75019, Paris, France
| | - David Klatzmann
- INSERM, Immunology-Immunopathology-Immunotherapy (i3), Sorbonne Université, Paris, France.,AP-HP, Hôpital Pitié-Salpêtrière, Biotherapy (CIC-BTi), Paris, France
| | - Richard Delorme
- AP-HP (Assistance Publique-Hôpitaux de Paris), Robert Debré Hospital, Child and Adolescent Psychiatry Department, Paris University, 48 Boulevard Sérurier, 75019, Paris, France.,Human Genetics and Cognitive Functions, Institut Pasteur, Paris, France
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Sensitive period for rescuing parvalbumin interneurons connectivity and social behavior deficits caused by TSC1 loss. Nat Commun 2021; 12:3653. [PMID: 34135323 PMCID: PMC8209106 DOI: 10.1038/s41467-021-23939-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 05/20/2021] [Indexed: 11/08/2022] Open
Abstract
The Mechanistic Target Of Rapamycin Complex 1 (mTORC1) pathway controls several aspects of neuronal development. Mutations in regulators of mTORC1, such as Tsc1 and Tsc2, lead to neurodevelopmental disorders associated with autism, intellectual disabilities and epilepsy. The correct development of inhibitory interneurons is crucial for functional circuits. In particular, the axonal arborisation and synapse density of parvalbumin (PV)-positive GABAergic interneurons change in the postnatal brain. How and whether mTORC1 signaling affects PV cell development is unknown. Here, we show that Tsc1 haploinsufficiency causes a premature increase in terminal axonal branching and bouton density formed by mutant PV cells, followed by a loss of perisomatic innervation in adult mice. PV cell-restricted Tsc1 haploinsufficient and knockout mice show deficits in social behavior. Finally, we identify a sensitive period during the third postnatal week during which treatment with the mTOR inhibitor Rapamycin rescues deficits in both PV cell innervation and social behavior in adult conditional haploinsufficient mice. Our findings reveal a role of mTORC1 signaling in the regulation of the developmental time course and maintenance of cortical PV cell connectivity and support a mechanistic basis for the targeted rescue of autism-related behaviors in disorders associated with deregulated mTORC1 signaling.
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Transcriptomic Changes Associated with Loss of Cell Viability Induced by Oxysterol Treatment of a Retinal Photoreceptor-Derived Cell Line: An In Vitro Model of Smith-Lemli-Opitz Syndrome. Int J Mol Sci 2021; 22:ijms22052339. [PMID: 33652836 PMCID: PMC7956713 DOI: 10.3390/ijms22052339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/19/2021] [Accepted: 02/21/2021] [Indexed: 11/17/2022] Open
Abstract
Smith–Lemli–Opitz Syndrome (SLOS) results from mutations in the gene encoding the enzyme DHCR7, which catalyzes conversion of 7-dehydrocholesterol (7DHC) to cholesterol (CHOL). Rats treated with a DHCR7 inhibitor serve as a SLOS animal model, and exhibit progressive photoreceptor-specific cell death, with accumulation of 7DHC and oxidized sterols. To understand the basis of this cell type specificity, we performed transcriptomic analyses on a photoreceptor-derived cell line (661W), treating cells with two 7DHC-derived oxysterols, which accumulate in tissues and bodily fluids of SLOS patients and in the rat SLOS model, as well as with CHOL (negative control), and evaluated differentially expressed genes (DEGs) for each treatment. Gene enrichment analysis and compilation of DEG sets indicated that endoplasmic reticulum stress, oxidative stress, DNA damage and repair, and autophagy were all highly up-regulated pathways in oxysterol-treated cells. Detailed analysis indicated that the two oxysterols exert their effects via different molecular mechanisms. Changes in expression of key genes in highlighted pathways (Hmox1, Ddit3, Trib3, and Herpud1) were validated by immunofluorescence confocal microscopy. The results extend our understanding of the pathobiology of retinal degeneration and SLOS, identifying potential new druggable targets for therapeutic intervention into these and other related orphan diseases.
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Richard P, Feng S, Tsai YL, Li W, Rinchetti P, Muhith U, Irizarry-Cole J, Stolz K, Sanz LA, Hartono S, Hoque M, Tadesse S, Seitz H, Lotti F, Hirano M, Chédin F, Tian B, Manley JL. SETX (senataxin), the helicase mutated in AOA2 and ALS4, functions in autophagy regulation. Autophagy 2020; 17:1889-1906. [PMID: 32686621 DOI: 10.1080/15548627.2020.1796292] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
SETX (senataxin) is an RNA/DNA helicase that has been implicated in transcriptional regulation and the DNA damage response through resolution of R-loop structures. Mutations in SETX result in either of two distinct neurodegenerative disorders. SETX dominant mutations result in a juvenile form of amyotrophic lateral sclerosis (ALS) called ALS4, whereas recessive mutations are responsible for ataxia called ataxia with oculomotor apraxia type 2 (AOA2). How mutations in the same protein can lead to different phenotypes is still unclear. To elucidate AOA2 disease mechanisms, we first examined gene expression changes following SETX depletion. We observed the effects on both transcription and RNA processing, but surprisingly observed decreased R-loop accumulation in SETX-depleted cells. Importantly, we discovered a strong connection between SETX and the macroautophagy/autophagy pathway, reflecting a direct effect on transcription of autophagy genes. We show that SETX depletion inhibits the progression of autophagy, leading to an accumulation of ubiquitinated proteins, decreased ability to clear protein aggregates, as well as mitochondrial defects. Analysis of AOA2 patient fibroblasts also revealed a perturbation of the autophagy pathway. Our work has thus identified a novel function for SETX in the regulation of autophagy, whose modulation may have a therapeutic impact for AOA2.Abbreviations: 3'READS: 3' region extraction and deep sequencing; ACTB: actin beta; ALS4: amyotrophic lateral sclerosis type 4; AOA2: ataxia with oculomotor apraxia type 2; APA: alternative polyadenylation; AS: alternative splicing; ATG7: autophagy-related 7; ATP6V0D2: ATPase H+ transporting V0 subunit D2; BAF: bafilomycin A1; BECN1: beclin 1; ChIP: chromatin IP; Chloro: chloroquine; CPT: camptothecin; DDR: DNA damage response; DNMT1: DNA methyltransferase 1; DRIP: DNA/RNA IP; DSBs: double strand breaks; EBs: embryoid bodies; FTD: frontotemporal dementia; GABARAP: GABA type A receptor-associated protein; GO: gene ontology; HR: homologous recombination; HTT: huntingtin; IF: immunofluorescence; IP: immunoprecipitation; iPSCs: induced pluripotent stem cells; KD: knockdown; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MN: motor neuron; MTORC1: mechanistic target of rapamycin kinase complex 1; PASS: PolyA Site Supporting; PFA: paraformaldehyde; RNAPII: RNA polymerase II; SCA: spinocerebellar ataxia; SETX: senataxin; SMA: spinal muscular atrophy; SMN1: survival of motor neuron 1, telomeric; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB; TSS: transcription start site; TTS: transcription termination site; ULK1: unc-51 like autophagy activating kinase 1; WB: western blot; WIPI2: WD repeat domain, phosphoinositide interacting 2; XRN2: 5'-3' exoribonuclease 2.
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Affiliation(s)
- Patricia Richard
- Department of Biological Sciences, Columbia University, New York, NY, USA.,Stellate Therapeutics, JLABS @ NYC, New York, NY, USA
| | | | - Yueh-Lin Tsai
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Wencheng Li
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Paola Rinchetti
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, USA.,Dino Ferrari Centre, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
| | - Ubayed Muhith
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Juan Irizarry-Cole
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Katharine Stolz
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Lionel A Sanz
- Department of Molecular and Cellular Biology and Genome Center, University of California, Davis, CA, USA
| | - Stella Hartono
- Department of Molecular and Cellular Biology and Genome Center, University of California, Davis, CA, USA
| | - Mainul Hoque
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Saba Tadesse
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, USA
| | - Hervé Seitz
- Institut de Génétique Humaine, UMR 9002 CNRS and Université de Montpellier, Montpellier, France
| | - Francesco Lotti
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Michio Hirano
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, USA
| | - Frédéric Chédin
- Department of Molecular and Cellular Biology and Genome Center, University of California, Davis, CA, USA
| | - Bin Tian
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ, USA.,Gene Expression and Regulation Program, and Center for Systems and Computational Biology, The Wistar Institute, Philadelphia, PA, USA
| | - James L Manley
- Department of Biological Sciences, Columbia University, New York, NY, USA
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Cook AA, Fields E, Watt AJ. Losing the Beat: Contribution of Purkinje Cell Firing Dysfunction to Disease, and Its Reversal. Neuroscience 2020; 462:247-261. [PMID: 32554108 DOI: 10.1016/j.neuroscience.2020.06.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 02/06/2023]
Abstract
The cerebellum is a brain structure that is highly interconnected with other brain regions. There are many contributing factors to cerebellar-related brain disease, such as altered afferent input, local connectivity, and/or cerebellar output. Purkinje cells (PC) are the principle cells of the cerebellar cortex, and fire intrinsically; that is, they fire spontaneous action potentials at high frequencies. This review paper focuses on PC intrinsic firing activity, which is altered in multiple neurological diseases, including ataxia, Huntington Disease (HD) and autism spectrum disorder (ASD). Notably, there are several cases where interventions that restore or rescue PC intrinsic activity also improve impaired behavior in these mouse models of disease. These findings suggest that rescuing PC firing deficits themselves may be sufficient to improve impairment in cerebellar-related behavior in disease. We propose that restoring PC intrinsic firing represents a good target for drug development that might be of therapeutic use for several disorders.
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Affiliation(s)
- Anna A Cook
- Department of Biology, McGill University, Montreal, Canada
| | - Eviatar Fields
- Department of Biology, McGill University, Montreal, Canada; Integrated Program in Neuroscience, McGill University, Montreal, Canada
| | - Alanna J Watt
- Department of Biology, McGill University, Montreal, Canada.
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Association of genes with phenotype in autism spectrum disorder. Aging (Albany NY) 2019; 11:10742-10770. [PMID: 31744938 PMCID: PMC6914398 DOI: 10.18632/aging.102473] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 11/08/2019] [Indexed: 12/27/2022]
Abstract
Autism spectrum disorder (ASD) is a genetic heterogeneous neurodevelopmental disorder that is characterized by impairments in social interaction and speech development and is accompanied by stereotypical behaviors such as body rocking, hand flapping, spinning objects, sniffing and restricted behaviors. The considerable significance of the genetics associated with autism has led to the identification of many risk genes for ASD used for the probing of ASD specificity and shared cognitive features over the past few decades. Identification of ASD risk genes helps to unravel various genetic variants and signaling pathways which are involved in ASD. This review highlights the role of ASD risk genes in gene transcription and translation regulation processes, as well as neuronal activity modulation, synaptic plasticity, disrupted key biological signaling pathways, and the novel candidate genes that play a significant role in the pathophysiology of ASD. The current emphasis on autism spectrum disorders has generated new opportunities in the field of neuroscience, and further advancements in the identification of different biomarkers, risk genes, and genetic pathways can help in the early diagnosis and development of new clinical and pharmacological treatments for ASD.
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