RESUMO
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare genetic disorder belonging to the group of vacuolating leukodystrophies. It is characterized by megalencephaly, loss of motor functions, epilepsy, and mild mental decline. In brain biopsies of MLC patients, vacuoles were observed in myelin and in astrocytes surrounding blood vessels. There is no therapy for MLC patients, only supportive treatment. We show here a preclinical gene therapy approach for MLC using the Mlc1 knock-out mouse. An adeno-associated virus coding for human MLC1 under the control of the glial fibrillary acidic protein promoter was injected in the cerebellar subarachnoid space of Mlc1 knock-out and wild-type animals at 2 months of age, before the onset of the disease, as a preventive approach. We also tested a therapeutic strategy by injecting the animals at 5 months, once the histopathological abnormalities are starting, or at 15 months, when they have progressed to a more severe pathology. MLC1 expression in the cerebellum restored the adhesion molecule GlialCAM and the chloride channel ClC-2 localization in Bergmann glia, which both are mislocalized in Mlc1 knock-out model. More importantly, myelin vacuolation was extremely reduced in treated mice at all ages and correlated with the amount of expressed MLC1 in Bergmann glia, indicating not only the preventive potential of this strategy but also its therapeutic capacity. In summary, here we provide the first therapeutic approach for patients affected with MLC. This work may have also implications to treat other diseases affecting motor function such as ataxias.
Assuntos
Astrócitos/patologia , Cerebelo/patologia , Cistos/patologia , Cistos/terapia , Terapia Genética/métodos , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/patologia , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/terapia , Fatores Etários , Animais , Astrócitos/ultraestrutura , Cerebelo/ultraestrutura , Cistos/genética , Células HEK293 , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/genética , Humanos , Camundongos , Camundongos KnockoutRESUMO
Introduction: Leukodystrophies constitute heterogenous group of rare heritable disorders primarily affecting the white matter of central nervous system. These conditions are often under-appreciated among physicians. The first clinical manifestations of leukodystrophies are often nonspecific and can occur in different ages from neonatal to late adulthood periods. The diagnosis is, therefore, challenging in most cases.Area covered: Herein, the authors discuss different aspects of leukodystrophies. The authors used MEDLINE, EMBASE, and GOOGLE SCHOLAR to provide an extensive update about epidemiology, classifications, pathology, clinical findings, diagnostic tools, and treatments of leukodystrophies. Comprehensive evaluation of clinical findings, brain magnetic resonance imaging, and genetic studies play the key roles in the early diagnosis of individuals with leukodystrophies. No cure is available for most heritable white matter disorders but symptomatic treatments can significantly decrease the burden of events. New genetic methods and stem cell transplantation are also under investigation to further increase the quality and duration of life in affected population.Expert opinion: The improvements in molecular diagnostic tools allow us to identify the meticulous underlying etiology of leukodystrophies and result in higher diagnostic rates, new classifications of leukodystrophies based on genetic information, and replacement of symptomatic managements with more specific targeted therapies.Abbreviations: 4H: Hypomyelination, hypogonadotropic hypogonadism and hypodontia; AAV: Adeno-associated virus; AD: autosomal dominant; AGS: Aicardi-Goutieres syndrome; ALSP: Axonal spheroids and pigmented glia; APGBD: Adult polyglucosan body disease; AR: autosomal recessive; ASO: Antisense oligonucleotide therapy; AxD: Alexander disease; BAEP: Brainstem auditory evoked potentials; CAA: Cerebral amyloid angiopathy; CADASIL: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy; CARASAL: Cathepsin A-related arteriopathy with strokes and leukoencephalopathy; CARASIL: Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy; CGH: Comparative genomic hybridization; ClC2: Chloride Ion Channel 2; CMTX: Charcot-Marie-Tooth disease, X-linked; CMV: Cytomegalovirus; CNS: central nervous system; CRISP/Cas9: Clustered regularly interspaced short palindromic repeat/CRISPR-associated 9; gRNA: Guide RNA; CTX: Cerebrotendinous xanthomatosis; DNA: Deoxyribonucleic acid; DSB: Double strand breaks; DTI: Diffusion tensor imaging; FLAIR: Fluid attenuated inversion recovery; GAN: Giant axonal neuropathy; H-ABC: Hypomyelination with atrophy of basal ganglia and cerebellum; HBSL: Hypomyelination with brainstem and spinal cord involvement and leg spasticity; HCC: Hypomyelination with congenital cataracts; HEMS: Hypomyelination of early myelinated structures; HMG CoA: Hydroxy methylglutaryl CoA; HSCT: Hematopoietic stem cell transplant; iPSC: Induced pluripotent stem cells; KSS: Kearns-Sayre syndrome; L-2-HGA: L-2-hydroxy glutaric aciduria; LBSL: Leukoencephalopathy with brainstem and spinal cord involvement and elevated lactate; LCC: Leukoencephalopathy with calcifications and cysts; LTBL: Leukoencephalopathy with thalamus and brainstem involvement and high lactate; MELAS: Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke; MERRF: Myoclonic epilepsy with ragged red fibers; MLC: Megalencephalic leukoencephalopathy with subcortical cysts; MLD: metachromatic leukodystrophy; MRI: magnetic resonance imaging; NCL: Neuronal ceroid lipofuscinosis; NGS: Next generation sequencing; ODDD: Oculodentodigital dysplasia; PCWH: Peripheral demyelinating neuropathy-central-dysmyelinating leukodystrophy-Waardenburg syndrome-Hirschprung disease; PMD: Pelizaeus-Merzbacher disease; PMDL: Pelizaeus-Merzbacher-like disease; RNA: Ribonucleic acid; TW: T-weighted; VWM: Vanishing white matter; WES: whole exome sequencing; WGS: whole genome sequencing; X-ALD: X-linked adrenoleukodystrophy; XLD: X-linked dominant; XLR: X-linked recessive.
Assuntos
Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central , Leucoencefalopatias , Criança , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/diagnóstico , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/patologia , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/terapia , Humanos , Leucoencefalopatias/diagnóstico , Leucoencefalopatias/patologia , Leucoencefalopatias/terapiaRESUMO
The leukodystrophies are a group of inherited white matter disorders with a heterogeneous genetic background, considerable phenotypic variability and disease onset at all ages. This Review focuses on leukodystrophies with major prevalence or primary onset in adulthood. We summarize 20 leukodystrophies with adult presentations, providing information on the underlying genetic mutations and on biochemical assays that aid diagnosis, where available. Definitions, clinical characteristics, age of onset, MRI findings and treatment options are all described, providing a comprehensive overview of the current knowledge of the various adulthood leukodystrophies. We highlight the distinction between adult-onset leukodystrophies and other inherited disorders with white matter involvement, and we propose a diagnostic pathway for timely recognition of adulthood leukodystrophies in a routine clinical setting. In addition, we provide detailed clinical information on selected adult-onset leukodystrophies, including X-linked adrenoleukodystrophy, metachromatic leukodystrophy, cerebrotendinous xanthomatosis, hereditary diffuse leukoencephalopathy with axonal spheroids, autosomal dominant adult-onset demyelinating leukodystrophy, adult polyglucosan body disease, and leukoencephalopathy with vanishing white matter. Ultimately, this Review aims to provide helpful suggestions to identify treatable adulthood leukodystrophies at an early stage in the disease course.
Assuntos
Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central , Leucoencefalopatias , Adulto , Idade de Início , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/diagnóstico , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/patologia , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/fisiopatologia , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/terapia , Humanos , Leucoencefalopatias/diagnóstico , Leucoencefalopatias/patologia , Leucoencefalopatias/fisiopatologia , Leucoencefalopatias/terapiaRESUMO
The concept of utilizing human cells for the treatment of medical conditions is not new. In its simplest form, blood product transfusion as treatment of severe hemorrhage has been practiced since the 1800s. The advent of hematopoietic stem cell transplantation (HSCT) began with the development of bone marrow transplantation for hematological malignancies in the mid-1900s and is now the standard of care for many hematological disorders. In the past few decades, HSCT has expanded to additional sources of donor cells, a wider range of indications, and the development of novel cell products. This trajectory has sparked a rapidly growing interest in the pursuit of innovative cell therapies to treat presently incurable diseases, including neurological conditions. HSCT is currently an established therapy for certain neurologically devastating inherited metabolic diseases, in which engrafting donor cells provide lifelong enzyme replacement that prevents neurological deterioration and significantly extends the lives of affected children. Knowledge gained from the treatment of these rare conditions has led to refinement of the indications and timing of HSCT, the study of additional cellular products and techniques to address its limitations, and the investigation of cellular therapies without transplantation to treat more common neurological conditions, such as autism spectrum disorder.
Assuntos
Transtorno do Espectro Autista/terapia , Doenças do Sistema Nervoso Central/terapia , Transplante de Células-Tronco Hematopoéticas , Doenças Metabólicas/terapia , Animais , Transtorno do Espectro Autista/genética , Transplante de Medula Óssea , Ensaios Clínicos como Assunto , Feminino , Doenças Genéticas Inatas/genética , Doenças Genéticas Inatas/terapia , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/terapia , Humanos , Masculino , Doenças Metabólicas/genética , Camundongos , Condicionamento Pré-TransplanteAssuntos
Ética em Pesquisa , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/terapia , Terapia Baseada em Transplante de Células e Tecidos , Cerebrosídeo Sulfatase/genética , Cerebrosídeo Sulfatase/metabolismo , Galactosilceramidase/genética , Galactosilceramidase/metabolismo , Terapia Genética , Vetores Genéticos/genética , Vetores Genéticos/metabolismo , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , HumanosRESUMO
Alternative splicing is an important regulator of the transcriptome. However, mutations may cause alteration of splicing patterns, which in turn leads to disease. During the past 10 years, exon skipping has been looked upon as a powerful tool for correction of missplicing in disease and progress has been made towards clinical trials. In this review, we discuss the use of antisense oligonucleotides to correct splicing defects through exon skipping, with a special focus on diseases affecting the nervous system, and the latest stage achieved in its progress.
Assuntos
Doenças Genéticas Inatas/genética , Doenças Genéticas Inatas/terapia , Doenças do Sistema Nervoso/genética , Doenças do Sistema Nervoso/terapia , Oligonucleotídeos Antissenso/genética , Oligonucleotídeos Antissenso/uso terapêutico , Reparo Gênico Alvo-Dirigido/métodos , Animais , Ataxia Telangiectasia/genética , Ataxia Telangiectasia/terapia , Barreira Hematoencefálica , Defeitos Congênitos da Glicosilação/genética , Defeitos Congênitos da Glicosilação/terapia , Cistos/genética , Cistos/terapia , Sistemas de Liberação de Medicamentos , Éxons , Demência Frontotemporal/genética , Demência Frontotemporal/terapia , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/genética , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/terapia , Humanos , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/terapia , Mutação , Neurofibromatoses/genética , Neurofibromatoses/terapia , Doença de Niemann-Pick Tipo C/genética , Doença de Niemann-Pick Tipo C/terapia , Oligonucleotídeos Antissenso/química , Doença de Pelizaeus-Merzbacher/genética , Doença de Pelizaeus-Merzbacher/terapia , Fosfotransferases (Fosfomutases)/deficiência , Fosfotransferases (Fosfomutases)/genética , Splicing de RNARESUMO
Leukodystrophies comprise a broad group of progressive, inherited disorders affecting mainly myelin. They often present after a variable period of normalcy with a variety of neurologic problems. Though the ultimate diagnosis is not found in many patients with leukodystrophies, distinctive features unique to them aid in diagnosis, treatment and prognostication. The clinical characteristics, etiologies, diagnostic testing and treatment options are reviewed in detail for some of the major leukodystrophies: X-linked adrenoleukodystrophy, Krabbe disease, metachromatic leukodystrophy, Pelizaeus-Merzbacher disease, Alexander disease, Canavan disease, megalencephalic leukoencephalopathy with subcortical cysts and vanishing white matter disease.
Assuntos
Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central , Doenças Neurodegenerativas , Encéfalo/patologia , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/classificação , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/diagnóstico , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/terapia , Humanos , Imageamento por Ressonância Magnética , Doenças Neurodegenerativas/diagnóstico , Doenças Neurodegenerativas/terapiaAssuntos
Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/diagnóstico , Adrenoleucodistrofia/diagnóstico , Adrenoleucodistrofia/genética , Adrenoleucodistrofia/terapia , Adulto , Encéfalo/patologia , Criança , Demência/diagnóstico , Demência/genética , Demência/terapia , Diagnóstico Diferencial , Avaliação da Deficiência , Progressão da Doença , Combinação de Medicamentos , Ácidos Erúcicos/uso terapêutico , Feminino , Marcha Atáxica/diagnóstico , Marcha Atáxica/genética , Marcha Atáxica/terapia , Transplante de Células-Tronco Hematopoéticas , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/genética , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/terapia , Humanos , Imageamento por Ressonância Magnética , Masculino , Espasticidade Muscular/diagnóstico , Espasticidade Muscular/genética , Espasticidade Muscular/terapia , Transtornos Psicóticos/diagnóstico , Transtornos Psicóticos/genética , Transtornos Psicóticos/terapia , Trioleína/uso terapêuticoRESUMO
The genetic myelin disorders are a range of diseases that manifest with severe neurological problems, often from infancy. It has been postulated for some time that stem cells might be an effective treatment for these disorders, primarily as agents to restore dysfunctional or lost myelin. Stem cells, however, may offer a wider range of therapeutic potential, for instance as vehicles to replace abnormal enzymes or genes, or to provide trophic support for residual CNS tissue. This article will review several of the more common genetic myelin disorders and currently available therapies, including bone marrow transplantation for adrenoleukodystrophy. Specific stem cell subtypes and their relevance to potential therapeutic use will be discussed and stem cell transplantation in animal model studies will also be reviewed.
Assuntos
Doenças Desmielinizantes/genética , Doenças Desmielinizantes/terapia , Medicina Regenerativa/métodos , Células-Tronco/citologia , Adrenoleucodistrofia/patologia , Adulto , Astrócitos/citologia , Transplante de Medula Óssea/métodos , Diferenciação Celular , Linhagem da Célula , Células-Tronco Embrionárias/citologia , Células-Tronco Hematopoéticas/citologia , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/genética , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/terapia , Humanos , Bainha de Mielina/metabolismo , Transplante de Células-TroncoRESUMO
This study characterized the therapeutic benefits of combining hematogenous cell replacement with lentiviral-mediated gene transfer of galactosylceramidase (GALC) in Twitcher mice, a bona fide model for Krabbe disease. Bone marrow cells and GALC-lentiviral vectors were administered intravenously without any preconditioning to newborn Twitcher pups before postnatal day 2. Treated Twitchers survived up to 4 months of age. GALC activity remained less than 5% of normal values in the nervous system for the first 2 months after treatment and reached approximately 30% in long-term-surviving mice. Long-term reconstitution of GALC activity in the nervous system was provided primarily by infiltrating macrophages and to a lesser extent by direct lentiviral transduction of neural cells. Treated Twitchers had significant preservation of myelin, with a G-ratio (ratio of the axon diameter to the diameter of the myelinated fiber) in sciatic nerve myelin of 0.75 +/- 0.08 compared with 0.85 +/- 0.10 in untreated mutants. Although treated mutants had improved locomotor activities during their long-term survival, they died with symptoms of progressive neurological degeneration, indistinguishable from those seen in untreated Twitchers. Examination of long-lived Twitchers showed that treated mutants were not protected from developing degeneration of axons throughout the neuroaxis. These results suggest that GALC deficiency not only affects myelinating glia but also leads to neuronal dysfunction. The contemporaneous neuropathology might help to explain the limited efficacy of current gene and cell therapies.