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Liang X, Gong M, Wang Z, Wang J, Guo W, Cai A, Yang Z, Liu X, Xu F, Xiong W, Fu C, Wang X. LncRNA TubAR complexes with TUBB4A and TUBA1A to promote microtubule assembly and maintain myelination. Cell Discov 2024; 10:54. [PMID: 38769343 PMCID: PMC11106304 DOI: 10.1038/s41421-024-00667-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 03/13/2024] [Indexed: 05/22/2024] Open
Abstract
A long-standing hypothesis proposes that certain RNA(s) must exhibit structural roles in microtubule assembly. Here, we identify a long noncoding RNA (TubAR) that is highly expressed in cerebellum and forms RNA-protein complex with TUBB4A and TUBA1A, two tubulins clinically linked to cerebellar and myelination defects. TubAR knockdown in mouse cerebellum causes loss of oligodendrocytes and Purkinje cells, demyelination, and decreased locomotor activity. Biochemically, we establish the roles of TubAR in promoting TUBB4A-TUBA1A heterodimer formation and microtubule assembly. Intriguingly, different from the hypomyelination-causing mutations, the non-hypomyelination-causing mutation TUBB4A-R2G confers gain-of-function for an RNA-independent interaction with TUBA1A. Experimental use of R2G/A mutations restores TUBB4A-TUBA1A heterodimer formation, and rescues the neuronal cell death phenotype caused by TubAR knockdown. Together, we uncover TubAR as the long-elusive structural RNA for microtubule assembly and demonstrate how TubAR mediates microtubule assembly specifically from αβ-tubulin heterodimers, which is crucial for maintenance of cerebellar myelination and activity.
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Affiliation(s)
- Xiaolin Liang
- Department of Geriatrics, Gerontology Institute of Anhui Province, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China
| | - Meng Gong
- Department of Geriatrics, Gerontology Institute of Anhui Province, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Zhikai Wang
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China
| | - Jie Wang
- Songjiang Hospital and Songjiang Research Institute, Shanghai Key Laboratory of Emotions and Affective Disorders, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Neuroscience and Brain Diseases, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei, China
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Weiwei Guo
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Aoling Cai
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Zhenye Yang
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China
| | - Xing Liu
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China
| | - Fuqiang Xu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Wei Xiong
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China.
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.
| | - Chuanhai Fu
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China.
| | - Xiangting Wang
- Department of Geriatrics, Gerontology Institute of Anhui Province, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China.
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China.
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2
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Williams LJ, Qiu J, Tchan M, Morris J, Morales‐Briceno H, Fung VS. Seeing What Is Not There: Revisiting a Diagnostic Conundrum in the Clinic. Mov Disord Clin Pract 2023; 10:S54-S57. [PMID: 37636225 PMCID: PMC10448618 DOI: 10.1002/mdc3.13767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/16/2023] [Accepted: 04/03/2023] [Indexed: 08/29/2023] Open
Affiliation(s)
- Laura J. Williams
- Movement Disorder Unit, Department of NeurologyWestmead HospitalWestmeadNew South WalesAustralia
| | - Jessica Qiu
- Movement Disorder Unit, Department of NeurologyWestmead HospitalWestmeadNew South WalesAustralia
| | - Michel Tchan
- Department of Medical GeneticsWestmead HospitalWestmeadNew South WalesAustralia
- Sydney Medical SchoolThe University of SydneySydneyNew South WalesAustralia
| | - John Morris
- Movement Disorder Unit, Department of NeurologyWestmead HospitalWestmeadNew South WalesAustralia
| | - Hugo Morales‐Briceno
- Movement Disorder Unit, Department of NeurologyWestmead HospitalWestmeadNew South WalesAustralia
| | - Victor S.C. Fung
- Movement Disorder Unit, Department of NeurologyWestmead HospitalWestmeadNew South WalesAustralia
- Sydney Medical SchoolThe University of SydneySydneyNew South WalesAustralia
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3
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Fellner A, Goldberg Y, Lev D, Basel-Salmon L, Shor O, Benninger F. In-silico phenotype prediction by normal mode variant analysis in TUBB4A-related disease. Sci Rep 2022; 12:58. [PMID: 34997144 PMCID: PMC8741991 DOI: 10.1038/s41598-021-04337-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 12/21/2021] [Indexed: 11/09/2022] Open
Abstract
TUBB4A-associated disorder is a rare condition affecting the central nervous system. It displays a wide phenotypic spectrum, ranging from isolated late-onset torsion dystonia to a severe early-onset disease with developmental delay, neurological deficits, and atrophy of the basal ganglia and cerebellum, therefore complicating variant interpretation and phenotype prediction in patients carrying TUBB4A variants. We applied entropy-based normal mode analysis (NMA) to investigate genotype–phenotype correlations in TUBB4A-releated disease and to develop an in-silico approach to assist in variant interpretation and phenotype prediction in this disorder. Variants included in our analysis were those reported prior to the conclusion of data collection for this study in October 2019. All TUBB4A pathogenic missense variants reported in ClinVar and Pubmed, for which associated clinical information was available, and all benign/likely benign TUBB4A missense variants reported in ClinVar, were included in the analysis. Pathogenic variants were divided into five phenotypic subgroups. In-silico point mutagenesis in the wild-type modeled protein structure was performed for each variant. Wild-type and mutated structures were analyzed by coarse-grained NMA to quantify protein stability as entropy difference value (ΔG) for each variant. Pairwise ΔG differences between all variant pairs in each structural cluster were calculated and clustered into dendrograms. Our search yielded 41 TUBB4A pathogenic variants in 126 patients, divided into 11 partially overlapping structural clusters across the TUBB4A protein. ΔG-based cluster analysis of the NMA results revealed a continuum of genotype–phenotype correlation across each structural cluster, as well as in transition areas of partially overlapping structural clusters. Benign/likely benign variants were integrated into the genotype–phenotype continuum as expected and were clearly separated from pathogenic variants. We conclude that our results support the incorporation of the NMA-based approach used in this study in the interpretation of variant pathogenicity and phenotype prediction in TUBB4A-related disease. Moreover, our results suggest that NMA may be of value in variant interpretation in additional monogenic conditions.
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Affiliation(s)
- Avi Fellner
- Raphael Recanati Genetics Institute, Rabin Medical Center, Beilinson Hospital, 49100, Petah Tikva, Israel. .,Department of Neurology, Rabin Medical Center, Beilinson Hospital, 49100, Petah Tikva, Israel.
| | - Yael Goldberg
- Raphael Recanati Genetics Institute, Rabin Medical Center, Beilinson Hospital, 49100, Petah Tikva, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, 69978, Tel-Aviv, Israel
| | - Dorit Lev
- Sackler Faculty of Medicine, Tel-Aviv University, 69978, Tel-Aviv, Israel.,Metabolic-Neurogenetic Clinic, Wolfson Medical Center, 58220, Holon, Israel.,Rina Mor Institute of Medical Genetics, Wolfson Medical Center, 58220, Holon, Israel
| | - Lina Basel-Salmon
- Raphael Recanati Genetics Institute, Rabin Medical Center, Beilinson Hospital, 49100, Petah Tikva, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, 69978, Tel-Aviv, Israel.,Felsenstein Medical Research Center, 49100, Petah Tikva, Israel
| | - Oded Shor
- Department of Neurology, Rabin Medical Center, Beilinson Hospital, 49100, Petah Tikva, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, 69978, Tel-Aviv, Israel.,Felsenstein Medical Research Center, 49100, Petah Tikva, Israel
| | - Felix Benninger
- Department of Neurology, Rabin Medical Center, Beilinson Hospital, 49100, Petah Tikva, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, 69978, Tel-Aviv, Israel.,Felsenstein Medical Research Center, 49100, Petah Tikva, Israel
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4
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Park K, Hoff KJ, Wethekam L, Stence N, Saenz M, Moore JK. Kinetically Stabilizing Mutations in Beta Tubulins Create Isotype-Specific Brain Malformations. Front Cell Dev Biol 2021; 9:765992. [PMID: 34869359 PMCID: PMC8637541 DOI: 10.3389/fcell.2021.765992] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 10/29/2021] [Indexed: 11/13/2022] Open
Abstract
Mutations in the family of genes encoding the tubulin subunits of microtubules are associated with a spectrum of human brain malformations known as tubulinopathies. How these mutations impact tubulin activity to give rise to distinct developmental consequences is poorly understood. Here we report two patients exhibiting brain malformations characteristic of tubulinopathies and heterozygous T178M missense mutations in different β-tubulin genes, TUBB2A or TUBB3. RNAseq analysis indicates that both TUBB2A and TUBB3 are expressed in the brain during development, but only TUBB2A maintains high expression in neurons into adulthood. The T178 residue is highly conserved in β-tubulins and located in the exchangeable GTP-binding pocket of β-tubulin. To determine the impact of T178M on β-tubulin function we created an analogous mutation in the β-tubulin of budding yeast and show that the substitution acts dominantly to produce kinetically stabilized microtubules that assemble and disassemble slowly, with fewer transitions between these states. In vitro experiments with purified mutant tubulin demonstrate that T178M decreases the intrinsic assembly activity of β-tubulin and forms microtubules that rarely transition to disassembly. We provide evidence that the T178M substitution disrupts GTPase-dependent conformational changes in tubulin, providing a mechanistic explanation for kinetic stabilization. Our findings demonstrate the importance of tubulin’s GTPase activity during brain development, and indicate that tubulin isotypes play different, important roles during brain development.
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Affiliation(s)
- Kristen Park
- Department of Pediatrics and Neurology, Children's Hospital Colorado, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Katelyn J Hoff
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Linnea Wethekam
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Nicholas Stence
- Section of Pediatric Radiology, Department of Radiology, Children's Hospital Colorado, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Margarita Saenz
- Section of Genetics, Department of Pediatrics, Children's Hospital Colorado, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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5
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Battini R, Milone R, Aiello C, Astrea G, Sferra A, Pasquariello R, Cioni G, Bertini E. Broadening the spectrum phenotype of TBCE-related neuron neurodegeneration. Brain Dev 2021; 43:939-944. [PMID: 34134906 DOI: 10.1016/j.braindev.2021.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 05/09/2021] [Accepted: 05/30/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND Severe loss of TBCE function has been related to two well-known dysmorphic syndromes, while TBCE hypomorphic variants have been linked to neurodegenerative conditions due to perturbed microtubule dynamics and homeostasis, with signs of central and peripheral nervous system involvement. METHOD We report on an Italian female originating from Southern Italy who presented early-onset regression and neurodegeneration, with neurological features of tetraparesis and signs of peripheral nervous system involvement. Her brain MRI revealed white matter involvement. RESULTS Analyzing all known hypomyelination leukodystrophies related genes, two mutations in TBCE (NM_001079515) were detected: the missense variant c.464 T > A; p. (Ile155Asn) and the frameshift variant c.924del; p. (Leu309Ter), in compound heterozygosity, already reported in the literature in patients coming from the same geographical area. The clinical phenotype of the proposita was more severe and with an earlier onset than the majority of the patients reported so far. CONCLUSIONS Next Generation Sequencing is becoming increasingly necessary to assess unusual phenotypes, with the opportunity to establish prognosis and disease mechanisms, and facilitating differential diagnosis.
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Affiliation(s)
- Roberta Battini
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, Calambrone, Pisa, Italy; Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.
| | - Roberta Milone
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, Calambrone, Pisa, Italy
| | - Chiara Aiello
- Unit of Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Ospedale Bambino Gesù Research Children's Hospital, IRCCS, Rome, Italy
| | - Guja Astrea
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, Calambrone, Pisa, Italy
| | - Antonella Sferra
- Unit of Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Ospedale Bambino Gesù Research Children's Hospital, IRCCS, Rome, Italy
| | - Rosa Pasquariello
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, Calambrone, Pisa, Italy
| | - Giovanni Cioni
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, Calambrone, Pisa, Italy; Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Ospedale Bambino Gesù Research Children's Hospital, IRCCS, Rome, Italy
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6
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Alata M, González-Vega A, Piazza V, Kleinert-Altamirano A, Cortes C, Ahumada-Juárez JC, Eguibar JR, López-Juárez A, Hernandez VH. Longitudinal Evaluation of Cerebellar Signs of H-ABC Tubulinopathy in a Patient and in the taiep Model. Front Neurol 2021; 12:702039. [PMID: 34335454 PMCID: PMC8317997 DOI: 10.3389/fneur.2021.702039] [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: 04/28/2021] [Accepted: 06/08/2021] [Indexed: 01/20/2023] Open
Abstract
Hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC) is a central neurodegenerative disease due to mutations in the tubulin beta-4A (TUBB4A) gene, characterized by motor development delay, abnormal movements, ataxia, spasticity, dysarthria, and cognitive deficits. Diagnosis is made by integrating clinical data and radiological signs. Differences in MRIs have been reported in patients that carry the same mutation; however, a quantitative study has not been performed so far. Our study aimed to provide a longitudinal analysis of the changes in the cerebellum (Cb), corpus callosum (CC), ventricular system, and striatum in a patient suffering from H-ABC and in the taiep rat. We correlated the MRI signs of the patient with the results of immunofluorescence, gait analysis, segmentation of cerebellum, CC, and ventricular system, performed in the taiep rat. We found that cerebellar and callosal changes, suggesting a potential hypomyelination, worsened with age, in concomitance with the emergence of ataxic gait. We also observed a progressive lateral ventriculomegaly in both patient and taiep, possibly secondary to the atrophy of the white matter. These white matter changes are progressive and can be involved in the clinical deterioration. Hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC) gives rise to a spectrum of clinical signs whose pathophysiology still needs to be understood.
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Affiliation(s)
| | - Arturo González-Vega
- Department of Chemical, Electronic and Biomedical Engineering, Division of Sciences and Engineering, University of Guanajuato, Guanajuato, Mexico
| | | | | | - Carmen Cortes
- Behavioral Neurophysiology Lab, Institute of Physiology, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Juan C Ahumada-Juárez
- Behavioral Neurophysiology Lab, Institute of Physiology, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Jose R Eguibar
- Behavioral Neurophysiology Lab, Institute of Physiology, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico.,Research Office, Vicerrectory of Research and Postgraduate Studies, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Alejandra López-Juárez
- Department of Chemical, Electronic and Biomedical Engineering, Division of Sciences and Engineering, University of Guanajuato, Guanajuato, Mexico
| | - Victor H Hernandez
- Department of Chemical, Electronic and Biomedical Engineering, Division of Sciences and Engineering, University of Guanajuato, Guanajuato, Mexico
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7
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Microtubule Dysfunction: A Common Feature of Neurodegenerative Diseases. Int J Mol Sci 2020; 21:ijms21197354. [PMID: 33027950 PMCID: PMC7582320 DOI: 10.3390/ijms21197354] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 09/24/2020] [Accepted: 10/01/2020] [Indexed: 12/13/2022] Open
Abstract
Neurons are particularly susceptible to microtubule (MT) defects and deregulation of the MT cytoskeleton is considered to be a common insult during the pathogenesis of neurodegenerative disorders. Evidence that dysfunctions in the MT system have a direct role in neurodegeneration comes from findings that several forms of neurodegenerative diseases are associated with changes in genes encoding tubulins, the structural units of MTs, MT-associated proteins (MAPs), or additional factors such as MT modifying enzymes which modulating tubulin post-translational modifications (PTMs) regulate MT functions and dynamics. Efforts to use MT-targeting therapeutic agents for the treatment of neurodegenerative diseases are underway. Many of these agents have provided several benefits when tested on both in vitro and in vivo neurodegenerative model systems. Currently, the most frequently addressed therapeutic interventions include drugs that modulate MT stability or that target tubulin PTMs, such as tubulin acetylation. The purpose of this review is to provide an update on the relevance of MT dysfunctions to the process of neurodegeneration and briefly discuss advances in the use of MT-targeting drugs for the treatment of neurodegenerative disorders.
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8
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Lopez-Juarez A, Gonzalez-Vega A, Kleinert-Altamirano A, Piazza V, Garduno-Robles A, Alata M, Villaseñor-Mora C, Eguibar JR, Cortes C, Padierna LC, Hernandez VH. Auditory impairment in H-ABC tubulinopathy. J Comp Neurol 2020; 529:957-968. [PMID: 32681585 DOI: 10.1002/cne.24990] [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: 04/22/2020] [Revised: 06/12/2020] [Accepted: 07/10/2020] [Indexed: 12/20/2022]
Abstract
Hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC) is a neurodegenerative disease due to mutations in TUBB4A. Patients suffer from extrapyramidal movements, spasticity, ataxia, and cognitive deficits. Magnetic resonance imaging features are hypomyelination and atrophy of the striatum and cerebellum. A correlation between the mutations and their cellular, tissue and organic effects is largely missing. The effects of these mutations on sensory functions have not been described so far. We have previously reported a rat carrying a TUBB4A (A302T) mutation and sharing most of the clinical and radiological signs with H-ABC patients. Here, for the first time, we did a comparative study of the hearing function in an H-ABC patient and in this mutant model. By analyzing hearing function, we found that there are no significant differences in the auditory brainstem response (ABR) thresholds between mutant rats and WT controls. Nevertheless, ABRs show longer latencies in central waves (II-IV) that in some cases disappear when compared to WT. The patient also shows abnormal AEPs presenting only Waves I and II. Distortion product of otoacoustic emissions and immunohistochemistry in the rat show that the peripheral hearing function and morphology of the organ of Corti are normal. We conclude that the tubulin mutation severely impairs the central hearing pathway most probably by progressive central white matter degeneration. Hearing function might be affected in a significant fraction of patients with H-ABC; therefore, screening for auditory function should be done on patients with tubulinopathies to evaluate hearing support therapies.
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Affiliation(s)
| | - Arturo Gonzalez-Vega
- Division of Sciences and Engineering, University of Guanajuato, Guanajuato, Mexico
| | | | | | - Angeles Garduno-Robles
- Division of Sciences and Engineering, University of Guanajuato, Guanajuato, Mexico.,Center of Research in Optics, Leon, Mexico
| | | | | | - Jose R Eguibar
- Institute of Physiology, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico.,Vicerrectoría de Investigación y Estudios de Posgrado, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Carmen Cortes
- Institute of Physiology, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Luis Carlos Padierna
- Division of Sciences and Engineering, University of Guanajuato, Guanajuato, Mexico
| | - Victor H Hernandez
- Division of Sciences and Engineering, University of Guanajuato, Guanajuato, Mexico
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9
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Malik P, Muthusamy K, Mankad K, Shroff M, Sudhakar S. Solving the hypomyelination conundrum - Imaging perspectives. Eur J Paediatr Neurol 2020; 27:9-24. [PMID: 32418752 DOI: 10.1016/j.ejpn.2020.04.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 03/25/2020] [Accepted: 04/14/2020] [Indexed: 11/26/2022]
Abstract
Hypomyelinating Leukodystrophies (HLDs) are a genetically heterogeneous, clinically overlapping group of disorders with the unifying MR imaging appearance of myelin deficit in the brain. In fact, it is the MRI phenotype that typically raises the diagnostic suspicion in this single largest group of undiagnosed leukodystrophies and guides gene testing for confirmation. This article reviews the neurobiology of myelination, focussing on the complex interplay of molecular genetic pathways and presents a practical clinico-radiological diagnostic algorithm based on the neuroimaging patterns of the common hypomyelinating disorders. The authors also address the current controversies about the definition and use of the term 'hypomyelination'.
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10
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Garduno-Robles A, Alata M, Piazza V, Cortes C, Eguibar JR, Pantano S, Hernandez VH. MRI Features in a Rat Model of H-ABC Tubulinopathy. Front Neurosci 2020; 14:555. [PMID: 32581692 PMCID: PMC7284052 DOI: 10.3389/fnins.2020.00555] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 05/05/2020] [Indexed: 11/22/2022] Open
Abstract
Tubulinopathies are a group of recently described diseases characterized by mutations in the tubulin genes. Mutations in TUBB4A produce diseases such as dystonia type 4 (DYT4) and hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC), which are clinically diagnosed by magnetic resonance imaging (MRI). We propose the taiep rat as the first animal model for tubulinopathies. The spontaneous mutant suffers from a syndrome related to a central leukodystrophy and characterized by tremor, ataxia, immobility, epilepsy, and paralysis. The pathological signs presented by these rats and the morphological changes we found by our longitudinal MRI study are similar to those of patients with mutations in TUBB4A. The diffuse atrophy we found in brain, cerebellum and spinal cord is related to the changes detectable in many human tubulinopathies and in particular in H-ABC patients, where myelin degeneration at the level of putamen and cerebellum is a clinical trademark of the disease. We performed Tubb4a exon analysis to corroborate the genetic defect and formulated hypotheses about the effect of amino acid 302 change on protein physiology. Optical microscopy of taiep rat cerebella and spinal cord confirmed the optical density loss in white matter associated with myelin loss, despite the persistence of neural fibers.
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Affiliation(s)
- Angeles Garduno-Robles
- Departament of Chemical, Electronic and Biomedical Engineering, DCI, University of Guanajuato, Guanajuato, Mexico.,Center of Research in Optics, Leon, Mexico
| | | | | | - Carmen Cortes
- Institute of Physiology, Benemerita Universidad Autonoma de Puebla, Puebla, Mexico
| | - Jose R Eguibar
- Institute of Physiology, Benemerita Universidad Autonoma de Puebla, Puebla, Mexico.,Research Office of the Vice-rectory of Research and Postgraduate Studies, Benemerita Universidad Autonoma de Puebla, Puebla, Mexico
| | - Sergio Pantano
- Group of Biomolecular Simulations, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Victor H Hernandez
- Departament of Chemical, Electronic and Biomedical Engineering, DCI, University of Guanajuato, Guanajuato, Mexico
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