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1.
Front Neurosci ; 17: 1216929, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37638318

RESUMEN

DYT-TOR1A dystonia is a neurological disorder characterized by involuntary muscle contractions and abnormal movements. It is a severe genetic form of dystonia caused by mutations in the TOR1A gene. TorsinA is a member of the AAA + family of adenosine triphosphatases (ATPases) involved in a variety of cellular functions, including protein folding, lipid metabolism, cytoskeletal organization, and nucleocytoskeletal coupling. Almost all patients with TOR1A-related dystonia harbor the same mutation, an in-frame GAG deletion (ΔGAG) in the last of its 5 exons. This recurrent variant results in the deletion of one of two tandem glutamic acid residues (i.e., E302/303) in a protein named torsinA [torsinA(△E)]. Although the mutation is hereditary, not all carriers will develop DYT-TOR1A dystonia, indicating the involvement of other factors in the disease process. The current understanding of the pathophysiology of DYT-TOR1A dystonia involves multiple factors, including abnormal protein folding, signaling between neurons and glial cells, and dysfunction of the protein quality control system. As there are currently no curative treatments for DYT-TOR1A dystonia, progress in research provides insight into its pathogenesis, leading to potential therapeutic and preventative strategies. This review summarizes the latest research advances in the pathogenesis, diagnosis, and treatment of DYT-TOR1A dystonia.

2.
Exp Neurol ; 367: 114471, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37321386

RESUMEN

Dystonia is a neurological movement disorder characterized by repetitive, unintentional movements and disabling postures that result from sustained or intermittent muscle contractions. The basal ganglia and cerebellum have received substantial focus in studying DYT1 dystonia. It remains unclear how cell-specific ∆GAG mutation of torsinA within specific cells of the basal ganglia or cerebellum affects motor performance, somatosensory network connectivity, and microstructure. In order to achieve this goal, we generated two genetically modified mouse models: in model 1 we performed Dyt1 ∆GAG conditional knock-in (KI) in neurons that express dopamine-2 receptors (D2-KI), and in model 2 we performed Dyt1 ∆GAG conditional KI in Purkinje cells of the cerebellum (Pcp2-KI). In both of these models, we used functional magnetic resonance imaging (fMRI) to assess sensory-evoked brain activation and resting-state functional connectivity, and diffusion MRI to assess brain microstructure. We found that D2-KI mutant mice had motor deficits, abnormal sensory-evoked brain activation in the somatosensory cortex, as well as increased functional connectivity of the anterior medulla with cortex. In contrast, we found that Pcp2-KI mice had improved motor performance, reduced sensory-evoked brain activation in the striatum and midbrain, as well as reduced functional connectivity of the striatum with the anterior medulla. These findings suggest that (1) D2 cell-specific Dyt1 ∆GAG mediated torsinA dysfunction in the basal ganglia results in detrimental effects on the sensorimotor network and motor output, and (2) Purkinje cell-specific Dyt1 ∆GAG mediated torsinA dysfunction in the cerebellum results in compensatory changes in the sensorimotor network that protect against dystonia-like motor deficits.


Asunto(s)
Distonía Muscular Deformante , Distonía , Ratones , Animales , Distonía/diagnóstico por imagen , Distonía/genética , Distonía/patología , Distonía Muscular Deformante/genética , Cerebelo/patología , Cuerpo Estriado/metabolismo , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo
4.
Behav Brain Res ; 439: 114221, 2023 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-36417958

RESUMEN

DYT1 or DYT-TOR1A dystonia is early-onset generalized dystonia caused by a trinucleotide deletion of GAG in the TOR1A or DYT1 gene leads to the loss of a glutamic acid residue in the resulting torsinA protein. A mouse model with overt dystonia is of unique importance to better understand the DYT1 pathophysiology and evaluate preclinical drug efficacy. DYT1 dystonia is likely a network disorder involving multiple brain regions, particularly the basal ganglia. Tor1a conditional knockout in the striatum or cerebral cortex leads to motor deficits, suggesting the importance of corticostriatal connection in the pathogenesis of dystonia. Indeed, corticostriatal long-term depression impairment has been demonstrated in multiple targeted DYT1 mouse models. Pappas and colleagues developed a conditional knockout line (Dlx-CKO) that inactivated Tor1a in the forebrain and surprisingly displayed overt dystonia. We set out to validate whether conditional knockout affecting both cortex and striatum would lead to overt dystonia and whether machine learning-based video behavioral analysis could be used to facilitate high throughput preclinical drug screening. We generated Dlx-CKO mice and found no overt dystonia or motor deficits at 4 months. At 8 months, retesting revealed motor deficits in rotarod, beam walking, grip strength, and hyperactivity in the open field; however, no overt dystonia was visually discernible or through the machine learning-based video analysis. Consistent with other targeted DYT1 mouse models, we observed age-dependent deficits in the beam walking test, which is likely a better motor behavioral test for preclinical drug testing but more labor-intensive when overt dystonia is absent.


Asunto(s)
Distonía Muscular Deformante , Distonía , Ratones , Animales , Distonía/genética , Ratones Noqueados , Prosencéfalo/metabolismo , Modelos Animales de Enfermedad , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo
5.
Dystonia ; 12022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-36329866

RESUMEN

DYT1 dystonia is an inherited early-onset movement disorder characterized by sustained muscle contractions causing twisting, repetitive movements, and abnormal postures. Most DYT1 patients have a heterozygous trinucleotide GAG deletion mutation (ΔGAG) in DYT1/TOR1A, coding for torsinA. Dyt1 heterozygous ΔGAG knock-in (KI) mice show motor deficits and reduced striatal dopamine receptor 2 (D2R). Striatal cholinergic interneurons (ChIs) are essential in regulating striatal motor circuits. Multiple dystonia rodent models, including KI mice, show altered ChI firing and modulation. However, due to the errors in assigning KI mice, it is essential to replicate these findings in genetically confirmed KI mice. Here, we found irregular and decreased spontaneous firing frequency in the acute brain slices from Dyt1 KI mice. Quinpirole, a D2R agonist, showed less inhibitory effect on the spontaneous ChI firing in Dyt1 KI mice, suggesting decreased D2R function on the striatal ChIs. On the other hand, a muscarinic receptor agonist, muscarine, inhibited the ChI firing in both wild-type (WT) and Dyt1 KI mice. Trihexyphenidyl, a muscarinic acetylcholine receptor M1 antagonist, had no significant effect on the firing. Moreover, the resting membrane property and functions of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, µ-opioid receptors, and large-conductance calcium-activated potassium (BK) channels were unaffected in Dyt1 KI mice. The results suggest that the irregular and low-frequency firing and decreased D2R function are the main alterations of striatal ChIs in Dyt1 KI mice. These results appear consistent with the reduced dopamine release and high striatal acetylcholine tone in the previous reports.

6.
Int J Mol Sci ; 23(15)2022 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-35955710

RESUMEN

Murine models are fundamental in the study of clinical conditions and the development of new drugs and treatments. Transgenic technology has started to offer advantages in oncology, encompassing all research fields related to the study of painful syndromes. Knockout mice or mice overexpressing genes encoding for proteins linked to pain development and maintenance can be produced and pain models can be applied to transgenic mice to model the most disabling neurological conditions. Due to the association of movement disorders with sensitivity and pain processing, our group focused for the first time on the role of the torsinA gene GAG deletion-responsible for DYT1 dystonia-in baseline sensitivity and neuropathic responses. The aim of the present report are to review the complex network that exists between the chaperonine-like protein torsinA and the baseline sensitivity pattern-which are fundamental in neuropathic pain-and to point at its possible role in neurodegenerative diseases.


Asunto(s)
Distonía , Trastornos Distónicos , Neuralgia , Animales , Modelos Animales de Enfermedad , Distonía/genética , Distonía/metabolismo , Ratones , Ratones Noqueados , Ratones Transgénicos , Chaperonas Moleculares/genética , Neuralgia/genética
7.
Int J Mol Sci ; 23(9)2022 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-35563018

RESUMEN

DYT1 dystonia is a debilitating neurological movement disorder that arises upon Torsin ATPase deficiency. Nuclear envelope (NE) blebs that contain FG-nucleoporins (FG-Nups) and K48-linked ubiquitin are the hallmark phenotype of Torsin manipulation across disease models of DYT1 dystonia. While the aberrant deposition of FG-Nups is caused by defective nuclear pore complex assembly, the source of K48-ubiquitylated proteins inside NE blebs is not known. Here, we demonstrate that the characteristic K48-ubiquitin accumulation inside blebs requires p97 activity. This activity is highly dependent on the p97 adaptor UBXD1. We show that p97 does not significantly depend on the Ufd1/Npl4 heterodimer to generate the K48-ubiquitylated proteins inside blebs, nor does inhibiting translation affect the ubiquitin sequestration in blebs. However, stimulating global ubiquitylation by heat shock greatly increases the amount of K48-ubiquitin sequestered inside blebs. These results suggest that blebs have an extraordinarily high capacity for sequestering ubiquitylated protein generated in a p97-dependent manner. The p97/UBXD1 axis is thus a major factor contributing to cellular DYT1 dystonia pathology and its modulation represents an unexplored potential for therapeutic development.


Asunto(s)
Proteínas Adaptadoras del Transporte Vesicular , Adenosina Trifosfatasas , Proteínas Relacionadas con la Autofagia , Distonía , Membrana Nuclear , Proteínas Nucleares , Proteínas Adaptadoras del Transporte Vesicular/genética , Proteínas Adaptadoras del Transporte Vesicular/metabolismo , Adenosina Trifosfatasas/metabolismo , Proteínas Relacionadas con la Autofagia/genética , Proteínas Relacionadas con la Autofagia/metabolismo , Estructuras de la Membrana Celular/metabolismo , Distonía/genética , Distonía/metabolismo , Distonía Muscular Deformante , Humanos , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Membrana Nuclear/metabolismo , Proteínas de Complejo Poro Nuclear/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Ubiquitina/metabolismo
8.
Neurobiol Dis ; 168: 105699, 2022 06 15.
Artículo en Inglés | MEDLINE | ID: mdl-35314320

RESUMEN

Trihexyphenidyl (THP), a non-selective muscarinic receptor (mAChR) antagonist, is commonly used for the treatment of dystonia associated with TOR1A, otherwise known as DYT1 dystonia. A better understanding of the mechanism of action of THP is a critical step in the development of better therapeutics with fewer side effects. We previously found that THP normalizes the deficit in striatal dopamine (DA) release in a mouse model of TOR1A dystonia (Tor1a+/ΔE knockin (KI) mice), revealing a plausible mechanism of action for this compound, considering that abnormal DA neurotransmission is consistently associated with many forms of dystonia. However, the mAChR subtype(s) that mediate the rescue of striatal dopamine release remain unclear. In this study we used a combination of pharmacological challenges and cell-type specific mAChR conditional knockout mice of either sex to determine which mAChR subtypes mediate the DA release-enhancing effects of THP. We determined that THP acts in part at M4 mAChR on striatal cholinergic interneurons to enhance DA release in both Tor1a+/+ and Tor1a+/ΔE KI mice. Further, we found that the subtype selective M4 antagonist VU6021625 recapitulates the effects of THP. These data implicate a principal role for M4 mAChR located on striatal cholinergic interneurons in the mechanism of action of THP and suggest that subtype selective M4 mAChR antagonists may be effective therapeutics with fewer side effects than THP for the treatment of TOR1A dystonia.


Asunto(s)
Distonía , Trastornos Distónicos , Animales , Colinérgicos/farmacología , Cuerpo Estriado/metabolismo , Modelos Animales de Enfermedad , Dopamina , Dopaminérgicos/farmacología , Distonía/tratamiento farmacológico , Interneuronas/metabolismo , Ratones , Ratones Noqueados , Chaperonas Moleculares , Receptores Muscarínicos/metabolismo , Trihexifenidilo/farmacología
9.
J Pediatr Endocrinol Metab ; 35(6): 845-850, 2022 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-35303767

RESUMEN

OBJECTIVES: Arthrogryposis multiplex congenita-5 (AMC5) is an autosomal recessive disease caused by homozygous or compound heterozygous mutations in the TOR1A gene on chromosome 9q34. Congenital multiple joint contractures with microcephaly, typical facial dysmorphism, developmental delay, strabismus, tremor, and increased tone are the main characteristics defined in seven patients thus far. One third of the individuals with monoallelic mutations of the gene develop isolated early-onset dystonia (DYT1 dystonia), which is inherited in an autosomal dominant fashion, with variable expressivity and incomplete penetrance. We believe that different inheritance patterns of the same gene resulting in different phenotypes will provide an opportunity to understand other similar disease groups and different aspects of gene functions. CASE PRESENTATION: We present a case with severe arthrogryposis multiplex congenita, respiratory failure, and feeding difficulties, with additional hitherto unreported symptoms, such as spontaneous bone fracture, sliding esophageal hernia, and uterine prolapse. The patient carried a novel homozygous variant (c.835delA, p.Lys275Asnfs*3) in the TOR1A gene (NM_000113.2). CONCLUSIONS: We want to contribute to the phenotypic and genotypic spectra of this extremely rare disease.


Asunto(s)
Artrogriposis , Distonía , Artrogriposis/genética , Femenino , Humanos , Chaperonas Moleculares/genética , Mutación , Linaje , Fenotipo
10.
Behav Brain Res ; 426: 113844, 2022 05 24.
Artículo en Inglés | MEDLINE | ID: mdl-35304183

RESUMEN

The dystonias are a group of movement disorders characterized by involuntary twisting movements and postures. A lack of well characterized behavioral models of dystonia has impeded identification of circuit abnormalities giving rise to the disease. Most mouse behavioral assays are implemented independently of cortex, but cortical dysfunction is implicated in human dystonia. It is therefore important to identify dystonia models in which motor cortex-dependent behaviors are altered in ways relevant to human disease. The goal of this study was to characterize a cortically-dependent behavior in the recently-developed Dlx-CKO mouse model of DYT1 dystonia. Mice performed two tasks: skilled reaching and water-elicited grooming. These tests assess motor learning, dexterous skill, and innate motor sequencing. Furthermore, skilled reaching depends strongly on motor cortex, while dorsal striatum is critical for normal grooming. Dlx-CKO mice exhibited significantly lower success rates and pellet contacts compared to control mice during skilled reaching. Despite the skilled reaching impairments, Dlx-CKO mice adapt their reaching strategies. With training, they more consistently contacted the target. Grooming patterns of Dlx-CKO mice are more disorganized than in control mice, as evidenced by a higher proportion of non-chain grooming. However, when Dlx-CKO mice engage in syntactic chains, they execute them similarly to control mice. These abnormalities may provide targets for preclinical intervention trials, as well as facilitate determination of the physiologic path from torsinA dysfunction to motor phenotype.


Asunto(s)
Distonía , Trastornos del Movimiento , Animales , Corteza Cerebral , Modelos Animales de Enfermedad , Distonía/genética , Humanos , Ratones , Chaperonas Moleculares/genética , Fenotipo
11.
Dystonia ; 12022.
Artículo en Inglés | MEDLINE | ID: mdl-36874764

RESUMEN

Animal models of DYT-TOR1A dystonia consistently demonstrate abnormalities of striatal cholinergic function, but the molecular pathways underlying this pathophysiology are unclear. To probe these molecular pathways in a genetic model of DYT-TOR1A, we performed laser microdissection in juvenile mice to isolate striatal cholinergic interneurons and non-cholinergic striatal tissue largely comprising spiny projection neurons during maturation. Both cholinergic and GABAergic enriched samples demonstrated a defined set of gene expression changes consistent with a role of torsinA in the secretory pathway. GABAergic enriched striatum samples also showed alteration to genes regulating synaptic transmission and an upregulation of activity dependent immediate early genes. Reconstruction of Golgi-Cox stained striatal spiny projection neurons from adult mice demonstrated significantly increased spiny density, suggesting that torsinA null striatal neurons have increased excitability during striatal maturation and long lasting increases in afferent input. These findings are consistent with a developmental role for torsinA in the secretory pathway and link torsinA loss of function with functional and structural changes of striatal cholinergic and GABAergic neurons. These transcriptomic datasets are freely available as a resource for future studies of torsinA loss of function-mediated striatal dysfunction.

12.
Data Brief ; 39: 107609, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34901342

RESUMEN

Here, we present quantitative subcellular compartment-specific proteomic data from wildtype and DYT-TOR1A heterozygous mouse embryonic fibroblasts (MEFs) basally and following thapsigargin (Tg) treatment [1]. In this experiment, we generated MEFs from wild type (WT) and a heterozygous DYT-TOR1A mouse model of dystonia. Subsequently, these MEF cultures were treated with either 1 µM Tg or dimethylsulfoxide vehicle (Veh) for six hours. Following treatment, the cells were fractionated into nuclear and cytosolic fractions. Liquid chromatography, tandem mass spectrometry (LC/MS/MS)-based proteomic profiling identified 65,056 unique peptides and 4801 unique proteins across all samples. The data presented here provide subcellular compartment-specific proteomic information within a dystonia model system both basally and under cellular stress. These data can inform future experiments focused on studying the function of TorsinA, the protein encoded by TOR1A, and its potential role in nucleocytoplasmic transport and proteostasis. In addition, the information in this article can also inform future mechanistic studies investigating the relationship between DYT-TOR1A dystonia and the cellular stress response to advance understanding of the pathogenesis of dystonia.

13.
Neurobiol Dis ; 158: 105464, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34358617

RESUMEN

TorsinA is a AAA+ ATPase that shuttles between the ER lumen and outer nuclear envelope in an ATP-dependent manner and is functionally implicated in nucleocytoplasmic transport. We hypothesized that the DYT-TOR1A dystonia disease-causing variant, ΔE TorsinA, may therefore disrupt the normal subcellular distribution of proteins between the nuclear and cytosolic compartments. To test this hypothesis, we performed proteomic analysis on nuclear and cytosolic subcellular fractions from DYT-TOR1A and wildtype mouse embryonic fibroblasts (MEFs). We further examined the compartmental proteomes following exposure to thapsigargin (Tg), an endoplasmic reticulum (ER) stressor, because DYT-TOR1A dystonia models have previously shown abnormalities in cellular stress responses. Across both subcellular compartments, proteomes of DYT-TOR1A cells showed basal state disruptions consistent with an activated stress response, and in response to thapsigargin, a blunted stress response. However, the DYT-TOR1A nuclear proteome under Tg cell stress showed the most pronounced and disproportionate degree of protein disruptions - 3-fold greater than all other conditions. The affected proteins extended beyond those typically associated with stress responses, including enrichments for processes critical for neuronal synaptic function. These findings highlight the advantage of subcellular proteomics to reveal events that localize to discrete subcellular compartments and refine thinking about the mechanisms and significance of cell stress in DYT-TOR1A pathogenesis.


Asunto(s)
Núcleo Celular/patología , Distonía/genética , Distonía/patología , Chaperonas Moleculares/genética , Proteómica , Estrés Fisiológico , Animales , Citosol/metabolismo , Estrés del Retículo Endoplásmico/efectos de los fármacos , Técnicas de Sustitución del Gen , Ratones , Ratones Endogámicos C57BL , Fracciones Subcelulares , Tapsigargina/farmacología
14.
Exp Neurol ; 343: 113783, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34119482

RESUMEN

DYT1 dystonia is a debilitating movement disorder characterized by repetitive, unintentional movements and postures. The disorder has been linked to mutation of the TOR1A/DYT1 gene encoding torsinA. Convergent evidence from studies in humans and animal models suggest that striatal medium spiny neurons and cholinergic neurons are important in DYT1 dystonia. What is not known is how torsinA dysfunction in these specific cell types contributes to the pathophysiology of DYT1 dystonia. In this study we sought to determine whether torsinA dysfunction in cholinergic neurons alone is sufficient to generate the sensorimotor dysfunction and brain changes associated with dystonia, or if torsinA dysfunction in a broader subset of cell types is needed. We generated two genetically modified mouse models, one with selective Dyt1 knock-out from dopamine-2 receptor expressing neurons (D2KO) and one where only cholinergic neurons are impacted (Ch2KO). We assessed motor deficits and performed in vivo 11.1 T functional MRI to assess sensory-evoked brain activation and connectivity, along with diffusion MRI to assess brain microstructure. We found that D2KO mice showed greater impairment than Ch2KO mice, including reduced sensory-evoked brain activity in key regions of the sensorimotor network, and altered functional connectivity of the striatum that correlated with motor deficits. These findings suggest that (1) the added impact of torsinA dysfunction in medium spiny and dopaminergic neurons of the basal ganglia generate more profound deficits than the dysfunction of cholinergic neurons alone, and (2) that sensory network impairments are linked to motor deficits in DYT1 dystonia.


Asunto(s)
Encéfalo/metabolismo , Distonía Muscular Deformante/metabolismo , Locomoción/fisiología , Chaperonas Moleculares/metabolismo , Red Nerviosa/metabolismo , Animales , Encéfalo/diagnóstico por imagen , Distonía Muscular Deformante/diagnóstico por imagen , Distonía Muscular Deformante/genética , Técnicas de Silenciamiento del Gen/métodos , Masculino , Ratones , Ratones Noqueados , Chaperonas Moleculares/genética , Red Nerviosa/diagnóstico por imagen
15.
Biochim Biophys Acta Mol Cell Res ; 1868(9): 119073, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34062155

RESUMEN

The Endoplasmic Reticulum (ER) is responsible for the folding and post-translational modification of secretory proteins, as well as for triaging misfolded proteins. During folding, there is a complex yet only partially understood interplay between disulfide bond formation, which is an enzyme catalyzed event in the oxidizing environment of the ER, along with other post-translational modifications (PTMs) and chaperone-supported protein folding. Here, we used the glycoprotein torsinA as a model substrate to explore the impact of ER redox homeostasis on PTMs and protein biogenesis. TorsinA is a AAA+ ATPase with unusual oligomeric properties and controversial functions. The deletion of a C-terminal glutamic acid residue (∆E) is associated with the development of Early-Onset Torsion Dystonia, a severe movement disorder. TorsinA differs from other AAA+ ATPases since it is an ER resident, and as a result of its entry into the ER torsinA contains two N-linked glycans and at least one disulfide bond. The role of these PTMs on torsinA biogenesis and function and the identity of the enzymes that catalyze them are poorly defined. Using a yeast torsinA expression system, we demonstrate that a specific protein disulfide isomerase, Pdi1, affects the folding and N-linked glycosylation of torsinA and torsinA∆E in a redox-dependent manner, suggesting that the acquisition of early torsinA folding intermediates is sensitive to perturbed interactions between Cys residues and the quality control machinery. We also highlight the role of specific Cys residues during torsinA biogenesis and demonstrate that torsinA∆E is more sensitive than torsinA when these Cys residues are mutated.


Asunto(s)
Adenosina Trifosfatasas/metabolismo , Homeostasis , Proteínas de Saccharomyces cerevisiae/metabolismo , Adenosina Trifosfatasas/química , Retículo Endoplásmico/metabolismo , Glicosilación , Modelos Moleculares , Oxidación-Reducción , Procesamiento Proteico-Postraduccional , Proteínas de Saccharomyces cerevisiae/química
16.
IBRO Neurosci Rep ; 11: 1-7, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34189496

RESUMEN

DYT-TOR1A or DYT1 early-onset generalized dystonia is an inherited movement disorder characterized by sustained muscle contractions causing twisting, repetitive movements, or abnormal postures. The majority of the DYT1 dystonia patients have a trinucleotide GAG deletion in DYT1/TOR1A. Trihexyphenidyl (THP), an antagonist for excitatory muscarinic acetylcholine receptor M1, is commonly used to treat dystonia. Dyt1 heterozygous ΔGAG knock-in (KI) mice, which have the corresponding mutation, exhibit impaired motor-skill transfer. Here, the effect of THP injection during the treadmill training period on the motor-skill transfer to the accelerated rotarod performance was examined. THP treatment reversed the motor-skill transfer impairment in Dyt1 KI mice. Immunohistochemistry showed that Dyt1 KI mice had a significant reduction of the dorsolateral striatal cholinergic interneurons. In contrast, Western blot analysis showed no significant alteration in the expression levels of the striatal enzymes and transporters involved in the acetylcholine metabolism. The results suggest a functional alteration of the cholinergic system underlying the impairment of motor-skill transfer and the pathogenesis of DYT1 dystonia. Training with THP in a motor task may improve another motor skill performance in DYT1 dystonia.

17.
Neurobiol Dis ; 155: 105369, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33894367

RESUMEN

TOR1A-associated dystonia, otherwise known as DYT1 dystonia, is an inherited dystonia caused by a three base-pair deletion in the TOR1A gene (TOR1AΔE). Although the mechanisms underlying the dystonic movements are largely unknown, abnormalities in striatal dopamine and acetylcholine neurotransmission are consistently implicated whereby dopamine release is reduced while cholinergic tone is increased. Because striatal cholinergic neurotransmission mediates dopamine release, it is not known if the dopamine release deficit is mediated indirectly by abnormal acetylcholine neurotransmission or if Tor1a(ΔE) acts directly within dopaminergic neurons to attenuate release. To dissect the microcircuit that governs the deficit in dopamine release, we conditionally expressed Tor1a(ΔE) in either dopamine neurons or cholinergic interneurons in mice and assessed striatal dopamine release using ex vivo fast scan cyclic voltammetry or dopamine efflux using in vivo microdialysis. Conditional expression of Tor1a(ΔE) in cholinergic neurons did not affect striatal dopamine release. In contrast, conditional expression of Tor1a(ΔE) in dopamine neurons reduced dopamine release to 50% of normal, which is comparable to the deficit in Tor1a+/ΔE knockin mice that express the mutation ubiquitously. Despite the deficit in dopamine release, we found that the Tor1a(ΔE) mutation does not cause obvious nerve terminal dysfunction as other presynaptic mechanisms, including electrical excitability, vesicle recycling/refilling, Ca2+ signaling, D2 dopamine autoreceptor function and GABAB receptor function, are intact. Although the mechanistic link between Tor1a(ΔE) and dopamine release is unclear, these results clearly demonstrate that the defect in dopamine release is caused by the action of the Tor1a(ΔE) mutation within dopamine neurons.


Asunto(s)
Modelos Animales de Enfermedad , Dopamina/genética , Dopamina/metabolismo , Distonía/genética , Distonía/metabolismo , Chaperonas Moleculares/genética , Animales , Cuerpo Estriado/metabolismo , Cuerpo Estriado/patología , Distonía/patología , Femenino , Captura por Microdisección con Láser/métodos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Chaperonas Moleculares/antagonistas & inhibidores , Mutación/fisiología
18.
Neurobiol Dis ; 154: 105342, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33757902

RESUMEN

Dystonia is a neurological movement disorder characterized by sustained or intermittent muscle contractions, repetitive movement, and sometimes abnormal postures. DYT1 dystonia is one of the most common genetic dystonias, and most patients carry heterozygous DYT1 ∆GAG mutations causing a loss of a glutamic acid of the protein torsinA. Patients can be treated with anticholinergics, such as trihexyphenidyl, suggesting an abnormal cholinergic state. Early work on the cell-autonomous effects of Dyt1 deletion with ChI-specific Dyt1 conditional knockout mice (Dyt1 Ch1KO) revealed abnormal electrophysiological responses of striatal ChIs to muscarine and quinpirole, motor deficits, and no changes in the number or size of the ChIs. However, the Chat-cre line that was used to derive Dyt1 Ch1KO mice contained a neomycin cassette and was reported to have ectopic cre-mediated recombination. In this study, we generated a Dyt1 Ch2KO mouse line by removing the neomycin cassette in Dyt1 Ch1KO mice. The Dyt1 Ch2KO mice showed abnormal paw clenching behavior, motor coordination and balance deficits, impaired motor learning, reduced striatal choline acetyltransferase protein level, and a reduced number of striatal ChIs. Furthermore, the mutant striatal ChIs had a normal muscarinic inhibitory function, impaired quinpirole-mediated inhibition, and altered current density. Our findings demonstrate a cell-autonomous effect of Dyt1 deletion on the striatal ChIs and a critical role for the striatal ChIs and corticostriatal pathway in the pathogenesis of DYT1 dystonia.


Asunto(s)
Neuronas Colinérgicas/metabolismo , Chaperonas Moleculares/antagonistas & inhibidores , Chaperonas Moleculares/genética , Trastornos Motores/genética , Trastornos Motores/metabolismo , Animales , Corteza Cerebral/metabolismo , Corteza Cerebral/patología , Neuronas Colinérgicas/patología , Cuerpo Estriado/metabolismo , Cuerpo Estriado/patología , Femenino , Masculino , Ratones , Ratones Noqueados , Ratones Transgénicos , Chaperonas Moleculares/biosíntesis , Trastornos Motores/patología
19.
Front Mol Biosci ; 7: 585643, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33134321

RESUMEN

TorsinA is a AAA+ ATPase involved in the severe neurological disease Early Onset Torsion Dystonia. Despite the impressive progress in the field in the recent years, the structural organization and function of this intriguing molecule is still not clear. One outstanding difference between torsinA and other AAA+ ATPases is that torsinA is a glycoprotein. TorsinA N-linked glycans impact torsinA biogenesis and subcellular localization. Here, we propose that torsinA glycans also modulate torsinA oligomerization properties. We used structural modeling to test this idea, and show that N-linked glycans appear to restrict torsinA's ability to form closed homohexameric ring assemblies, and instead promote an open hexameric conformation that allows torsinA interaction with key cofactors required for ATP hydrolysis. This mechanism would make torsinA a prime example of Nature's sophisticated molecular glycoengineering.

20.
Proc Natl Acad Sci U S A ; 117(49): 31301-31308, 2020 12 08.
Artículo en Inglés | MEDLINE | ID: mdl-33229589

RESUMEN

The function of the nucleus depends on the integrity of the nuclear lamina, an intermediate filament network associated with the linker of nucleoskeleton and cytoskeleton (LINC) complex. The LINC complex spans the nuclear envelope and mediates nuclear mechanotransduction, the process by which mechanical signals and forces are transmitted across the nuclear envelope. In turn, the AAA+ ATPase torsinA is thought to regulate force transmission from the cytoskeleton to the nucleus. In humans, mutations affecting nuclear envelope-associated proteins cause laminopathies, including progeria, myopathy, and dystonia, though the extent to which endogenous mechanical stresses contribute to these pathologies is unclear. Here, we use the Caenorhabditis elegans germline as a model to investigate mechanisms that maintain nuclear integrity as germ cell nuclei progress through meiotic development and migrate for gametogenesis-processes that require LINC complex function. We report that decreasing the function of the C. elegans torsinA homolog, OOC-5, rescues the sterility and premature aging caused by a null mutation in the single worm lamin homolog. We show that decreasing OOC-5/torsinA activity prevents nuclear collapse in lamin mutants by disrupting the function of the LINC complex. At a mechanistic level, OOC-5/torsinA promotes the assembly or maintenance of the lamin-associated LINC complex and this activity is also important for interphase nuclear pore complex insertion into growing germline nuclei. These results demonstrate that LINC complex-transmitted forces damage nuclei with a compromised nuclear lamina. Thus, the torsinA-LINC complex nexus might comprise a therapeutic target for certain laminopathies by preventing damage from endogenous cellular forces.


Asunto(s)
Caenorhabditis elegans/metabolismo , Núcleo Celular/metabolismo , Laminopatías/patología , Mecanotransducción Celular , Animales , Proteínas de Caenorhabditis elegans/metabolismo , Interfase , Longevidad , Meiosis , Modelos Biológicos , Mutación/genética , Poro Nuclear/metabolismo , Profase
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