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1.
Nat Chem Biol ; 15(12): 1191-1198, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31636429

RESUMO

Splicing modifiers promoting SMN2 exon 7 inclusion have the potential to treat spinal muscular atrophy, the leading genetic cause of infantile death. These small molecules are SMN2 exon 7 selective and act during the early stages of spliceosome assembly. Here, we show at atomic resolution how the drug selectively promotes the recognition of the weak 5' splice site of SMN2 exon 7 by U1 snRNP. The solution structure of the RNA duplex formed following 5' splice site recognition in the presence of the splicing modifier revealed that the drug specifically stabilizes a bulged adenine at this exon-intron junction and converts the weak 5' splice site of SMN2 exon 7 into a stronger one. The small molecule acts as a specific splicing enhancer cooperatively with the splicing regulatory network. Our investigations uncovered a novel concept for gene-specific alternative splicing correction that we coined 5' splice site bulge repair.


Assuntos
Processamento de RNA , RNA/química , Conformação Molecular , Atrofia Muscular Espinal/metabolismo , Ribonucleoproteína Nuclear Pequena U1/química
2.
Biofactors ; 45(5): 666-689, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31185140

RESUMO

Curcumin is widely consumed in Asia either as turmeric directly or as one of the culinary ingredients in food recipes. The benefits of curcumin in different organ systems have been reported extensively in several neurological diseases and cancer. Curcumin has got its global recognition because of its strong antioxidant, anti-inflammatory, anti-cancer, and antimicrobial activities. Additionally, it is used in diabetes and arthritis as well as in hepatic, renal, and cardiovascular diseases. Recently, there is growing attention on usage of curcumin to prevent or delay the onset of neurodegenerative diseases. This review summarizes available data from several recent studies on curcumin in various neurological diseases such as Alzheimer's disease, Parkinson's disease, Multiple Sclerosis, Huntington's disease, Prions disease, stroke, Down's syndrome, autism, Amyotrophic lateral sclerosis, anxiety, depression, and aging. Recent advancements toward increasing the therapeutic efficacy of curcuma/curcumin formulation and the novel delivery strategies employed to overcome its minimal bioavailability and toxicity studies have also been discussed. This review also summarizes the ongoing clinical trials on curcumin for different neurodegenerative diseases and patent details of curcuma/curcumin in India.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Curcumina/farmacologia , Demência/tratamento farmacológico , Sistemas de Liberação de Medicamentos/métodos , Fármacos Neuroprotetores/farmacologia , Doença de Parkinson/tratamento farmacológico , Doença de Alzheimer/metabolismo , Doença de Alzheimer/fisiopatologia , Esclerose Amiotrófica Lateral/tratamento farmacológico , Esclerose Amiotrófica Lateral/metabolismo , Esclerose Amiotrófica Lateral/fisiopatologia , Animais , Ansiedade/tratamento farmacológico , Ansiedade/metabolismo , Ansiedade/fisiopatologia , Transtorno Autístico/tratamento farmacológico , Transtorno Autístico/metabolismo , Transtorno Autístico/fisiopatologia , Disponibilidade Biológica , Curcuma/química , Curcumina/isolamento & purificação , Demência/metabolismo , Demência/fisiopatologia , Depressão/tratamento farmacológico , Depressão/metabolismo , Depressão/fisiopatologia , Glioma/tratamento farmacológico , Glioma/metabolismo , Glioma/fisiopatologia , Humanos , Doença de Huntington/tratamento farmacológico , Doença de Huntington/metabolismo , Doença de Huntington/fisiopatologia , Esclerose Múltipla/tratamento farmacológico , Esclerose Múltipla/metabolismo , Esclerose Múltipla/fisiopatologia , Atrofia Muscular Espinal/tratamento farmacológico , Atrofia Muscular Espinal/metabolismo , Atrofia Muscular Espinal/fisiopatologia , Fármacos Neuroprotetores/isolamento & purificação , Doença de Parkinson/metabolismo , Doença de Parkinson/fisiopatologia , Patentes como Assunto , Doenças Priônicas/tratamento farmacológico , Doenças Priônicas/metabolismo , Doenças Priônicas/fisiopatologia , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/metabolismo , Acidente Vascular Cerebral/fisiopatologia
3.
Int J Mol Sci ; 20(6)2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30875922

RESUMO

Spinal bulbar muscular atrophy (SBMA) is a slowly progressive, androgen-dependent neuromuscular disease in men that is characterized by both muscle and synaptic dysfunction. Because gene expression in muscle is heterogeneous, with synaptic myonuclei expressing genes that regulate synaptic function and extrasynaptic myonuclei expressing genes to regulate contractile function, we used quantitative PCR to compare gene expression in these two domains of muscle from three different mouse models of SBMA: the "97Q" model that ubiquitously expresses mutant human androgen receptor (AR), the 113Q knock-in (KI) model that expresses humanized mouse AR with an expanded glutamine tract, and the "myogenic" model that overexpresses wild-type rat AR only in skeletal muscle. We were particularly interested in neurotrophic factors because of their role in maintaining neuromuscular function via effects on both muscle and synaptic function, and their implicated role in SBMA. We confirmed previous reports of the enriched expression of select genes (e.g., the acetylcholine receptor) in the synaptic region of muscle, and are the first to report the synaptic enrichment of others (e.g., glial cell line-derived neurotrophic factor). Interestingly, all three models displayed comparably dysregulated expression of most genes examined in both the synaptic and extrasynaptic domains of muscle, with only modest differences between regions and models. These findings of comprehensive gene dysregulation in muscle support the emerging view that skeletal muscle may be a prime therapeutic target for restoring function of both muscles and motoneurons in SBMA.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/genética , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Músculo Esquelético/metabolismo , Atrofia Muscular Espinal/genética , Receptores Androgênicos/genética , Animais , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Técnicas de Introdução de Genes , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Atrofia Muscular Espinal/metabolismo , Ratos , Receptores Androgênicos/metabolismo
5.
Neuropathology ; 39(1): 47-53, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30511354

RESUMO

Amyotrophic lateral sclerosis (ALS) primarily affects upper and lower motor neurons. Phosphorylated trans-activation response DNA-binding protein of 43 kDa (TDP-43) inclusion bodies are reportedly a pathological hallmark of sporadic ALS. Here, we present an atypical case of sporadic ALS that progressed very slowly, persisted for 19 years, and clinically appeared to only affect the lower motor neurons; however, upper motor neuron degeneration was detected at autopsy. Furthermore, no inclusion bodies positive for phosphorylated TDP-43, ubiquitin, fused in sarcoma, or superoxide dismutase-1 were detected in the central nervous system. We performed exome-sequencing data analysis but found no genetic disorders. This was therefore an unusual case of lower motor neuron-predominant ALS without TDP-43 pathology or known gene-disease associations. We also reviewed autopsied ALS cases that progressed slowly and had no phosphorylated TDP-43 or ubiquitin-positive inclusions and present the clinicopathological features of such cases. Based on these results, there may be a sporadic ALS subgroup that progresses slowly and shows no accumulation of phosphorylated TDP-43.


Assuntos
Esclerose Amiotrófica Lateral/patologia , Progressão da Doença , Atrofia Muscular Espinal/patologia , Esclerose Amiotrófica Lateral/complicações , Esclerose Amiotrófica Lateral/metabolismo , Proteínas de Ligação a DNA/metabolismo , Feminino , Humanos , Corpos de Inclusão/metabolismo , Pessoa de Meia-Idade , Atrofia Muscular Espinal/complicações , Atrofia Muscular Espinal/metabolismo
6.
Folia Histochem Cytobiol ; 56(4): 215-221, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30565205

RESUMO

INTRODUCTION: Spinal muscular atrophy (SMA) is one of the most common genetic causes of death in infants due to a mutation of the motor neuron 1 (SMN1) gene. The SMN1 gene encodes for the multifunctional SMN protein. SMN has been shown to be implicated in pre-mRNA splicing, mRNA transport and translational control. Also other mRNA processing proteins, such as GLE1, Marten (MART3) and Fused in Sarcoma (FUS), have been linked to neurodegenerative diseases. The aim of the study was to determine the expression of SMN, GLE1, MART3 and FUS genes in cell lines of the fibroblasts derived from SMA patients and normal controls. MATERIAL AND METHODS: Total RNA was extracted from purchased fibroblasts acquired from three SMA type I patients and fibroblasts of three age-matched healthy controls. The RNA was then subjected to qPCR analysis using primers specific for the GLE1, MART3, FUS and SMN1 genes vs. GAPDH as internal control gene. RESULTS: SMN1 mRNA levels were at least ×10 lower in fibroblasts of SMA patients compared to controls. Gle1 and MART3 gene expression was ×2 downregulated whereas FUS mRNA levels appeared to be ×3 upregulated in SMA cells when compared to controls. We found a high correlation between FUS gene expression level to the SMN1 at gene expression level of fibroblast cell lines of SMA type I patients (r = 0.994, p < 0.0001). CONCLUSIONS: Our preliminary data show an intriguing expression profile of Gle1, MART3 and FUS genes in SMA, and suggest a critical role of FUS protein in the SMA pathogenesis.


Assuntos
Fibroblastos/metabolismo , Regulação da Expressão Gênica , Atrofia Muscular Espinal/metabolismo , Proteínas de Transporte Nucleocitoplasmático/biossíntese , Proteína FUS de Ligação a RNA/biossíntese , Proteína 1 de Sobrevivência do Neurônio Motor/biossíntese , Linhagem Celular , Fibroblastos/patologia , Humanos , Atrofia Muscular Espinal/patologia
7.
Nucleic Acids Res ; 46(22): 11939-11951, 2018 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-30398641

RESUMO

Understanding the molecular pathways disrupted in motor neuron diseases is urgently needed. Here, we employed CRISPR knockout (KO) to investigate the functions of four ALS-causative RNA/DNA binding proteins (FUS, EWSR1, TAF15 and MATR3) within the RNAP II/U1 snRNP machinery. We found that each of these structurally related proteins has distinct roles with FUS KO resulting in loss of U1 snRNP and the SMN complex, EWSR1 KO causing dissociation of the tRNA ligase complex, and TAF15 KO resulting in loss of transcription factors P-TEFb and TFIIF. However, all four ALS-causative proteins are required for association of the ASC-1 transcriptional co-activator complex with the RNAP II/U1 snRNP machinery. Remarkably, mutations in the ASC-1 complex are known to cause a severe form of Spinal Muscular Atrophy (SMA), and we show that an SMA-causative mutation in an ASC-1 component or an ALS-causative mutation in FUS disrupts association between the ASC-1 complex and the RNAP II/U1 snRNP machinery. We conclude that ALS and SMA are more intimately tied to one another than previously thought, being linked via the ASC-1 complex.


Assuntos
Esclerose Amiotrófica Lateral/genética , Atrofia Muscular Espinal/genética , Proteínas Associadas à Matriz Nuclear/genética , Proteína EWS de Ligação a RNA/genética , Proteína FUS de Ligação a RNA/genética , Proteínas de Ligação a RNA/genética , Fatores Associados à Proteína de Ligação a TATA/genética , Esclerose Amiotrófica Lateral/metabolismo , Esclerose Amiotrófica Lateral/patologia , Sistemas CRISPR-Cas , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , DNA Helicases/genética , DNA Helicases/metabolismo , Edição de Genes , Regulação da Expressão Gênica , Técnicas de Inativação de Genes , Humanos , Atrofia Muscular Espinal/metabolismo , Atrofia Muscular Espinal/patologia , Proteínas Associadas à Matriz Nuclear/deficiência , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Fator B de Elongação Transcricional Positiva/genética , Fator B de Elongação Transcricional Positiva/metabolismo , RNA Polimerase II/genética , RNA Polimerase II/metabolismo , RNA de Transferência/genética , RNA de Transferência/metabolismo , Proteína EWS de Ligação a RNA/deficiência , Proteína FUS de Ligação a RNA/deficiência , Ribonucleoproteína Nuclear Pequena U1/genética , Ribonucleoproteína Nuclear Pequena U1/metabolismo , Spliceossomos/química , Spliceossomos/metabolismo , Fatores Associados à Proteína de Ligação a TATA/deficiência , Fatores de Transcrição TFII/genética , Fatores de Transcrição TFII/metabolismo
8.
Cell Death Dis ; 9(11): 1100, 2018 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-30368521

RESUMO

Spinal Muscular Atrophy (SMA) is caused by genetic mutations in the SMN1 gene, resulting in drastically reduced levels of Survival of Motor Neuron (SMN) protein. Although SMN is ubiquitously expressed, spinal motor neurons are one of the most affected cell types. Previous studies have identified pathways uniquely activated in SMA motor neurons, including a hyperactivated ER stress pathway, neuronal hyperexcitability, and defective spliceosomes. To investigate why motor neurons are more affected than other neural types, we developed a spinal organoid model of SMA. We demonstrate overt motor neuron degeneration in SMA spinal organoids, and this degeneration can be prevented using a small molecule inhibitor of CDK4/6, indicating that spinal organoids are an ideal platform for therapeutic discovery.


Assuntos
Quinase 4 Dependente de Ciclina/genética , Quinase 6 Dependente de Ciclina/genética , Neurônios Motores/efeitos dos fármacos , Organoides/efeitos dos fármacos , Piperazinas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Piridinas/farmacologia , Bibliotecas de Moléculas Pequenas/farmacologia , Proteína Quinase CDC2/antagonistas & inibidores , Proteína Quinase CDC2/genética , Proteína Quinase CDC2/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/genética , Diferenciação Celular , Linhagem Celular , Colágeno/química , Quinase 2 Dependente de Ciclina/antagonistas & inibidores , Quinase 2 Dependente de Ciclina/genética , Quinase 2 Dependente de Ciclina/metabolismo , Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 4 Dependente de Ciclina/metabolismo , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Quinase 6 Dependente de Ciclina/metabolismo , Combinação de Medicamentos , Corpos Embrioides/efeitos dos fármacos , Corpos Embrioides/metabolismo , Corpos Embrioides/patologia , Regulação da Expressão Gênica , Humanos , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes Induzidas/patologia , Laminina/química , Modelos Biológicos , Neurônios Motores/metabolismo , Neurônios Motores/patologia , Atrofia Muscular Espinal/tratamento farmacológico , Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/metabolismo , Atrofia Muscular Espinal/patologia , Organoides/metabolismo , Organoides/patologia , Cultura Primária de Células , Proteoglicanas/química , Transdução de Sinais , Proteína 1 de Sobrevivência do Neurônio Motor/genética , Proteína 1 de Sobrevivência do Neurônio Motor/metabolismo
9.
PLoS One ; 13(10): e0205589, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30304024

RESUMO

Spinal muscular atrophy (SMA) is a severe genetic disorder that manifests in progressive neuromuscular degeneration. SMA originates from loss-of-function mutations of the SMN1 (Survival of Motor Neuron 1) gene. Recent evidence has implicated peripheral deficits, especially in skeletal muscle, as key contributors to disease progression in SMA. In this study we generated myogenic cells from two SMA-affected human embryonic stem cell (hESC) lines with deletion of SMN1 bearing two copies of the SMN2 gene and recapitulating the molecular phenotype of Type 1 SMA. We characterized myoblasts and myotubes by comparing them to two unaffected, control hESC lines and demonstrate that SMA myoblasts and myotubes showed altered expression of various myogenic markers, which translated into an impaired in vitro myogenic maturation and development process. Additionally, we provide evidence that these SMN1 deficient cells display functional deficits in cholinergic calcium signaling response, glycolysis and oxidative phosphorylation. Our data describe a novel human myogenic SMA model that might be used for interrogating the effect of SMN depletion during skeletal muscle development, and as model to investigate biological mechanisms targeting myogenic differentiation, mitochondrial respiration and calcium signaling processes in SMA muscle cells.


Assuntos
Células-Tronco Embrionárias Humanas/metabolismo , Desenvolvimento Muscular/fisiologia , Fibras Musculares Esqueléticas/metabolismo , Atrofia Muscular Espinal/metabolismo , Mioblastos/metabolismo , Trifosfato de Adenosina/metabolismo , Cálcio/metabolismo , Cátions Bivalentes/metabolismo , Linhagem Celular , Expressão Gênica , Células-Tronco Embrionárias Humanas/patologia , Humanos , Fibras Musculares Esqueléticas/patologia , Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/patologia , Mioblastos/patologia , Receptores Colinérgicos/metabolismo , Proteína 1 de Sobrevivência do Neurônio Motor/genética , Proteína 1 de Sobrevivência do Neurônio Motor/metabolismo , Proteína 2 de Sobrevivência do Neurônio Motor/genética , Proteína 2 de Sobrevivência do Neurônio Motor/metabolismo
10.
Brain ; 141(10): 2878-2894, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-30239612

RESUMO

Deafferentation of motor neurons as a result of defective sensory-motor connectivity is a critical early event in the pathogenesis of spinal muscular atrophy, but the underlying molecular pathways remain unknown. We show that restoration of ubiquitin-like modifier-activating enzyme 1 (UBA1) was sufficient to correct sensory-motor connectivity in the spinal cord of mice with spinal muscular atrophy. Aminoacyl-tRNA synthetases, including GARS, were identified as downstream targets of UBA1. Regulation of GARS by UBA1 occurred via a non-canonical pathway independent of ubiquitylation. Dysregulation of UBA1/GARS pathways in spinal muscular atrophy mice disrupted sensory neuron fate, phenocopying GARS-dependent defects associated with Charcot-Marie-Tooth disease. Sensory neuron fate was corrected following restoration of UBA1 expression and UBA1/GARS pathways in spinal muscular atrophy mice. We conclude that defective sensory motor connectivity in spinal muscular atrophy results from perturbations in a UBA1/GARS pathway that modulates sensory neuron fate, thereby highlighting significant molecular and phenotypic overlap between spinal muscular atrophy and Charcot-Marie-Tooth disease.


Assuntos
Aminoacil-tRNA Sintetases/metabolismo , Atrofia Muscular Espinal/patologia , Vias Neurais/patologia , Enzimas Ativadoras de Ubiquitina/metabolismo , Animais , Gânglios Espinais/metabolismo , Gânglios Espinais/patologia , Regulação da Expressão Gênica/fisiologia , Células HEK293 , Humanos , Camundongos , Neurônios Motores/metabolismo , Neurônios Motores/patologia , Atrofia Muscular Espinal/metabolismo , Vias Neurais/metabolismo , Células Receptoras Sensoriais/metabolismo , Células Receptoras Sensoriais/patologia , Transdução de Sinais/fisiologia , Medula Espinal/metabolismo , Medula Espinal/patologia
11.
PLoS One ; 13(9): e0203398, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30188931

RESUMO

OBJECTIVES: Spinal muscular atrophy (SMA) is a devastating motor neuron disorder caused by homozygous loss of the survival motor neuron 1 (SMN1) gene and insufficient functional SMN protein produced by the SMN2 copy gene. Additional genetic protective modifiers such as Plastin 3 (PLS3) can counteract SMA pathology despite insufficient SMN protein. Recently, Spinraza, an SMN antisense oligonucleotide (ASO) that restores full-length SMN2 transcripts, has been FDA- and EMA-approved for SMA therapy. Hence, the availability of biomarkers allowing a reliable monitoring of disease and therapy progression would be of great importance. Our objectives were (i) to analyse the feasibility of SMN and of six SMA biomarkers identified by the BforSMA study in the Taiwanese SMA mouse model, (ii) to analyse the effect of PLS3 overexpression on these biomarkers, and (iii) to assess the impact of low-dose SMN-ASO therapy on the level of SMN and the six biomarkers. METHODS: At P10 and P21, the level of SMN and six putative biomarkers were compared among SMA, heterozygous and wild type mice, with or without PLS3 overexpression, and with or without presymptomatic low-dose SMN-ASO subcutaneous injection. SMN levels were measured in whole blood by ECL immunoassay and of six SMA putative biomarkers, namely Cartilage Oligomeric Matrix Protein (COMP), Dipeptidyl Peptidase 4 (DPP4), Tetranectin (C-type Lectin Family 3 Member B, CLEC3B), Osteopontin (Secreted Phosphoprotein 1, SPP1), Vitronectin (VTN) and Fetuin A (Alpha 2-HS Glycoprotein, AHSG) in plasma. RESULTS: SMN levels were significantly discernible between SMA, heterozygous and wild type mice. However, no significant differences were measured upon low-dose SMN-ASO treatment compared to untreated animals. Of the six biomarkers, only COMP and DPP4 showed high and SPP1 moderate correlation with the SMA phenotype. PLS3 overexpression neither influenced the SMN level nor the six biomarkers, supporting the hypothesis that PLS3 acts as an independent protective modifier.


Assuntos
Regulação da Expressão Gênica/efeitos dos fármacos , Glicoproteínas de Membrana , Proteínas dos Microfilamentos , Atrofia Muscular Espinal , Oligodesoxirribonucleotídeos Antissenso/farmacologia , Proteína 1 de Sobrevivência do Neurônio Motor , Animais , Biomarcadores/metabolismo , Glicoproteínas de Membrana/biossíntese , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Knockout , Proteínas dos Microfilamentos/biossíntese , Proteínas dos Microfilamentos/genética , Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/metabolismo , Atrofia Muscular Espinal/patologia , Atrofia Muscular Espinal/terapia , Proteína 1 de Sobrevivência do Neurônio Motor/antagonistas & inibidores , Proteína 1 de Sobrevivência do Neurônio Motor/biossíntese , Proteína 1 de Sobrevivência do Neurônio Motor/genética
12.
Hum Mol Genet ; 27(23): 4061-4076, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30137324

RESUMO

Spinal muscular atrophy (SMA) is a fatal genetic disease, mainly affecting children. A number of recent studies show, aside from lower motor neuron degeneration and atrophy of skeletal muscles, widespread defects present in the central nervous system (CNS) and peripheral non-neuronal cell types of SMA patients and mouse models, particularly of severe forms. However, molecular mechanisms underlying the multi-organ manifestations of SMA were hardly understood. Here, using histology, flow cytometry and gene expression analysis in both messenger RNA and protein levels in various tissues, we found that a severe SMA mouse model develops systemic inflammation in early symptomatic stages. SMA mice had an enhanced intestinal permeability, resulting in microbial invasion into the circulatory system. Expression of proinflammatory cytokines was increased in all tissues and the acute phase response in the liver was activated. Systemic inflammation further mobilized glucocorticoid signaling and in turn led to dysregulation of a large set of genes, including robust upregulation of FAM107A in the spinal cord, increased expression of which has been implicated in neurodegeneration. Moreover, we show that lipopolysaccharide challenge markedly suppressed survival of motor neuron 2 exon 7 splicing in all examined peripheral and CNS tissues, resulting in global survival of motor neuron level reduction. Therefore, we identified a novel pathological mechanism in a severe SMA mouse model, which affects phenotypic severity through multiple paths and should contribute to progression of broad neuronal and non-neuronal defects.


Assuntos
Inflamação/genética , Atrofia Muscular Espinal/genética , Proteína 1 de Sobrevivência do Neurônio Motor/genética , Proteína 2 de Sobrevivência do Neurônio Motor/genética , Proteínas Supressoras de Tumor/genética , Animais , Sistema Nervoso Central/metabolismo , Sistema Nervoso Central/fisiopatologia , Citocinas/genética , Modelos Animais de Doenças , Citometria de Fluxo , Regulação da Expressão Gênica/genética , Humanos , Inflamação/induzido quimicamente , Inflamação/fisiopatologia , Lipopolissacarídeos/toxicidade , Camundongos , Camundongos Transgênicos , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiopatologia , Atrofia Muscular Espinal/metabolismo , Atrofia Muscular Espinal/fisiopatologia , Medula Espinal/metabolismo , Medula Espinal/fisiopatologia
13.
J Clin Invest ; 128(8): 3219-3227, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29985170

RESUMO

The motor neuron disease spinal muscular atrophy (SMA) is caused by recessive, loss-of-function mutations of the survival motor neuron 1 gene (SMN1). Alone, such mutations are embryonically lethal, but SMA patients retain a paralog gene, SMN2, that undergoes alternative pre-mRNA splicing, producing low levels of SMN protein. By mechanisms that are not well understood, reduced expression of the ubiquitously expressed SMN protein causes an early-onset motor neuron disease that often results in infantile or childhood mortality. Recently, striking clinical improvements have resulted from two novel treatment strategies to increase SMN protein by (a) modulating the splicing of existing SMN2 pre-mRNAs using antisense oligonucleotides, and (b) transducing motor neurons with self-complementary adeno-associated virus 9 (scAAV9) expressing exogenous SMN1 cDNA. We review the recently published clinical trial results and discuss the differing administration, tissue targeting, and potential toxicities of these two therapies. We also focus on the challenges that remain, emphasizing the many clinical and biologic questions that remain open. Answers to these questions will enable further optimization of these remarkable SMA treatments as well as provide insights that may well be useful in application of these therapeutic platforms to other diseases.


Assuntos
Marcação de Genes/métodos , Atrofia Muscular Espinal , Oligonucleotídeos Antissenso/uso terapêutico , Proteína 1 de Sobrevivência do Neurônio Motor , Dependovirus , Humanos , Neurônios Motores/metabolismo , Neurônios Motores/patologia , Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/metabolismo , Atrofia Muscular Espinal/terapia , Oligonucleotídeos Antissenso/genética , Processamento de RNA/genética , Proteína 1 de Sobrevivência do Neurônio Motor/genética , Proteína 1 de Sobrevivência do Neurônio Motor/metabolismo , Proteína 2 de Sobrevivência do Neurônio Motor/genética , Proteína 2 de Sobrevivência do Neurônio Motor/metabolismo
14.
Hum Mol Genet ; 27(19): 3404-3416, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-29982416

RESUMO

Spinal muscular atrophy (SMA) is caused by reduced levels of full-length SMN (FL-SMN). In SMA patients with one or two copies of the Survival Motor Neuron 2 (SMN2) gene there are a number of SMN missense mutations that result in milder-than-predicted SMA phenotypes. These mild SMN missense mutation alleles are often assumed to have partial function. However, it is important to consider the contribution of FL-SMN as these missense alleles never occur in the absence of SMN2. We propose that these patients contain a partially functional oligomeric SMN complex consisting of FL-SMN from SMN2 and mutant SMN protein produced from the missense allele. Here we show that mild SMN missense mutations SMND44V, SMNT74I or SMNQ282A alone do not rescue mice lacking wild-type FL-SMN. Thus, missense mutations are not functional in the absence of FL-SMN. In contrast, when the same mild SMN missense mutations are expressed in a mouse containing two SMN2 copies, functional SMN complexes are formed with the small amount of wild-type FL-SMN produced by SMN2 and the SMA phenotype is completely rescued. This contrasts with SMN missense alleles when studied in C. elegans, Drosophila and zebrafish. Here we demonstrate that the heteromeric SMN complex formed with FL-SMN is functional and sufficient to rescue small nuclear ribonucleoprotein assembly, motor neuron function and rescue the SMA mice. We conclude that mild SMN missense alleles are not partially functional but rather they are completely non-functional in the absence of wild-type SMN in mammals.


Assuntos
Atrofia Muscular Espinal/genética , Ribonucleoproteínas Nucleares Pequenas/genética , Proteínas do Complexo SMN/genética , Alelos , Animais , Caenorhabditis elegans/genética , Linhagem Celular , Modelos Animais de Doenças , Drosophila melanogaster/genética , Éxons/genética , Humanos , Camundongos , Camundongos Transgênicos , Neurônios Motores/metabolismo , Neurônios Motores/patologia , Atrofia Muscular Espinal/metabolismo , Atrofia Muscular Espinal/patologia , Mutação de Sentido Incorreto , Ribonucleoproteínas Nucleares Pequenas/química , Proteínas do Complexo SMN/química , Proteína 2 de Sobrevivência do Neurônio Motor/química , Proteína 2 de Sobrevivência do Neurônio Motor/genética , Peixe-Zebra/genética
15.
Hum Mol Genet ; 27(20): 3582-3597, 2018 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-29982483

RESUMO

Physiology and behaviour are critically dependent on circadian regulation via a core set of clock genes, dysregulation of which leads to metabolic and sleep disturbances. Metabolic and sleep perturbations occur in spinal muscular atrophy (SMA), a neuromuscular disorder caused by loss of the survival motor neuron (SMN) protein and characterized by motor neuron loss and muscle atrophy. We therefore investigated the expression of circadian rhythm genes in various metabolic tissues and spinal cord of the Taiwanese Smn-/-;SMN2 SMA animal model. We demonstrate a dysregulated expression of the core clock genes (clock, ARNTL/Bmal1, Cry1/2, Per1/2) and clock output genes (Nr1d1 and Dbp) in SMA tissues during disease progression. We also uncover an age- and tissue-dependent diurnal expression of the Smn gene. Importantly, we observe molecular and phenotypic corrections in SMA mice following direct light modulation. Our study identifies a key relationship between an SMA pathology and peripheral core clock gene dysregulation, highlights the influence of SMN on peripheral circadian regulation and metabolism and has significant implications for the development of peripheral therapeutic approaches and clinical care management of SMA patients.


Assuntos
Ritmo Circadiano/efeitos da radiação , Regulação da Expressão Gênica , Luz , Atrofia Muscular Espinal/metabolismo , Animais , Ritmo Circadiano/genética , Modelos Animais de Doenças , Progressão da Doença , Feminino , Técnicas de Inativação de Genes , Masculino , Camundongos , Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/fisiopatologia , Proteína 1 de Sobrevivência do Neurônio Motor/genética
16.
Nat Cell Biol ; 20(8): 917-927, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30050118

RESUMO

Fibro-adipogenic progenitors (FAPs) are typically activated in response to muscle injury, and establish functional interactions with inflammatory and muscle stem cells (MuSCs) to promote muscle repair. We found that denervation causes progressive accumulation of FAPs, without concomitant infiltration of macrophages and MuSC-mediated regeneration. Denervation-activated FAPs exhibited persistent STAT3 activation and secreted elevated levels of IL-6, which promoted muscle atrophy and fibrosis. FAPs with aberrant activation of STAT3-IL-6 signalling were also found in mouse models of spinal cord injury, spinal muscular atrophy, amyotrophic lateral sclerosis (ALS) and in muscles of ALS patients. Inactivation of STAT3-IL-6 signalling in FAPs effectively countered muscle atrophy and fibrosis in mouse models of acute denervation and ALS (SODG93A mice). Activation of pathogenic FAPs following loss of integrity of neuromuscular junctions further illustrates the functional versatility of FAPs in response to homeostatic perturbations and suggests their potential contribution to the pathogenesis of neuromuscular diseases.


Assuntos
Adipogenia , Esclerose Amiotrófica Lateral/metabolismo , Denervação/métodos , Interleucina-6/metabolismo , Atrofia Muscular Espinal/metabolismo , Atrofia Muscular/metabolismo , Mioblastos Esqueléticos/metabolismo , Músculo Quadríceps/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais , Traumatismos da Medula Espinal/metabolismo , Adipogenia/efeitos dos fármacos , Esclerose Amiotrófica Lateral/genética , Esclerose Amiotrófica Lateral/patologia , Esclerose Amiotrófica Lateral/prevenção & controle , Animais , Cardiotoxinas , Linhagem Celular , Técnicas de Cocultura , Modelos Animais de Doenças , Fibrose , Humanos , Interleucina-6/antagonistas & inibidores , Interleucina-6/genética , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Atrofia Muscular/genética , Atrofia Muscular/patologia , Atrofia Muscular/prevenção & controle , Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/patologia , Atrofia Muscular Espinal/prevenção & controle , Mutação , Mioblastos Esqueléticos/efeitos dos fármacos , Mioblastos Esqueléticos/patologia , Fármacos Neuromusculares/farmacologia , Músculo Quadríceps/efeitos dos fármacos , Músculo Quadríceps/inervação , Músculo Quadríceps/patologia , Fator de Transcrição STAT3/antagonistas & inibidores , Fator de Transcrição STAT3/genética , Nervo Isquiático/cirurgia , Traumatismos da Medula Espinal/genética , Traumatismos da Medula Espinal/patologia , Traumatismos da Medula Espinal/prevenção & controle , Superóxido Dismutase-1/genética
17.
Orphanet J Rare Dis ; 13(1): 121, 2018 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-30029679

RESUMO

Acid ceramidase (ACDase) deficiency is a spectrum of disorders that includes a rare lysosomal storage disorder called Farber disease (FD) and a rare epileptic disorder called spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME). Both disorders are caused by mutations in the ASAH1 gene that encodes the lysosomal hydrolase that breaks down the bioactive lipid ceramide. To date, there have been fewer than 200 reported cases of FD and SMA-PME in the literature. Typical textbook manifestations of classical FD include the formation of subcutaneous nodules, accumulation of joint contractures, and development of a hoarse voice. In reality, however, the clinical presentation is much broader. Patients may develop severe pathologies leading to death in infancy or may develop attenuated forms of the disorder wherein they are often misdiagnosed or not diagnosed until adulthood. A clinical variability also exists for SMA-PME, in which patients develop progressive muscle weakness and seizures. Currently, there is no known cure for FD or for SMA-PME. The main treatment is symptom management. In rare cases, treatment may include surgery or hematopoietic stem cell transplantation. Research using disease models has provided insights into the pathology as well as the role of ACDase in the development of these conditions. Recent studies have highlighted possible biomarkers for an effective diagnosis of ACDase deficiency. Ongoing work is being conducted to evaluate the use of recombinant human ACDase (rhACDase) for the treatment of FD. Finally, gene therapy strategies for the treatment of ACDase deficiency are actively being pursued. This review highlights the broad clinical definition and outlines key studies that have improved our understanding of inherited ACDase deficiency-related conditions.


Assuntos
Lipogranulomatose de Farber/metabolismo , Lipogranulomatose de Farber/patologia , Atrofia Muscular Espinal/metabolismo , Atrofia Muscular Espinal/patologia , Epilepsias Mioclônicas Progressivas/metabolismo , Epilepsias Mioclônicas Progressivas/patologia , Animais , Lipogranulomatose de Farber/cirurgia , Lipogranulomatose de Farber/terapia , Humanos , Atrofia Muscular Espinal/cirurgia , Atrofia Muscular Espinal/terapia , Epilepsias Mioclônicas Progressivas/cirurgia , Epilepsias Mioclônicas Progressivas/terapia , Esfingolipídeos/metabolismo
18.
Genes Dev ; 32(15-16): 1045-1059, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30012555

RESUMO

Ubiquitous deficiency in the survival motor neuron (SMN) protein causes death of motor neurons-a hallmark of the neurodegenerative disease spinal muscular atrophy (SMA)-through poorly understood mechanisms. Here, we show that the function of SMN in the assembly of spliceosomal small nuclear ribonucleoproteins (snRNPs) regulates alternative splicing of Mdm2 and Mdm4, two nonredundant repressors of p53. Decreased inclusion of critical Mdm2 and Mdm4 exons is most prominent in SMA motor neurons and correlates with both snRNP reduction and p53 activation in vivo. Importantly, increased skipping of Mdm2 and Mdm4 exons regulated by SMN is necessary and sufficient to synergistically elicit robust p53 activation in wild-type mice. Conversely, restoration of full-length Mdm2 and Mdm4 suppresses p53 induction and motor neuron degeneration in SMA mice. These findings reveal that loss of SMN-dependent regulation of Mdm2 and Mdm4 alternative splicing underlies p53-mediated death of motor neurons in SMA, establishing a causal link between snRNP dysfunction and neurodegeneration.


Assuntos
Processamento Alternativo , Neurônios Motores/metabolismo , Atrofia Muscular Espinal/genética , Proteínas Proto-Oncogênicas c-mdm2/genética , Proteínas Proto-Oncogênicas/genética , Animais , Morte Celular , Éxons , Camundongos , Neurônios Motores/patologia , Atrofia Muscular Espinal/metabolismo , Atrofia Muscular Espinal/fisiopatologia , Células NIH 3T3 , Degeneração Neural/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Ribonucleoproteínas Nucleares Pequenas/biossíntese , Proteína Supressora de Tumor p53/metabolismo
19.
Cell Mol Life Sci ; 75(21): 3877-3894, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29872871

RESUMO

Ever since loss of survival motor neuron (SMN) protein was identified as the direct cause of the childhood inherited neurodegenerative disorder spinal muscular atrophy, significant efforts have been made to reveal the molecular functions of this ubiquitously expressed protein. Resulting research demonstrated that SMN plays important roles in multiple fundamental cellular homeostatic pathways, including a well-characterised role in the assembly of the spliceosome and biogenesis of ribonucleoproteins. More recent studies have shown that SMN is also involved in other housekeeping processes, including mRNA trafficking and local translation, cytoskeletal dynamics, endocytosis and autophagy. Moreover, SMN has been shown to influence mitochondria and bioenergetic pathways as well as regulate function of the ubiquitin-proteasome system. In this review, we summarise these diverse functions of SMN, confirming its key role in maintenance of the homeostatic environment of the cell.


Assuntos
Atrofia Muscular Espinal/metabolismo , Proteostase , Proteínas do Complexo SMN/metabolismo , Animais , Autofagia , Citoesqueleto/genética , Citoesqueleto/metabolismo , Citoesqueleto/patologia , Endocitose , Metabolismo Energético , Humanos , Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/patologia , Biossíntese de Proteínas , Ribonucleoproteínas/genética , Ribonucleoproteínas/metabolismo , Proteínas do Complexo SMN/genética , Ubiquitina/genética , Ubiquitina/metabolismo
20.
Adv Neurobiol ; 20: 31-61, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29916015

RESUMO

Spinal muscular atrophy (SMA) is one of the major genetic disorders associated with infant mortality. More than 90% cases of SMA result from deletions or mutations of Survival Motor Neuron 1 (SMN1) gene. SMN2, a nearly identical copy of SMN1, does not compensate for the loss of SMN1 due to predominant skipping of exon 7. However, correction of SMN2 exon 7 splicing has proven to confer therapeutic benefits in SMA patients. The only approved drug for SMA is an antisense oligonucleotide (Spinraza™/Nusinersen), which corrects SMN2 exon 7 splicing by blocking intronic splicing silencer N1 (ISS-N1) located immediately downstream of exon 7. ISS-N1 is a complex regulatory element encompassing overlapping negative motifs and sequestering a cryptic splice site. More than 40 protein factors have been implicated in the regulation of SMN exon 7 splicing. There is evidence to support that multiple exons of SMN are alternatively spliced during oxidative stress, which is associated with a growing number of pathological conditions. Here, we provide the most up to date account of the mechanism of splicing regulation of the SMN genes.


Assuntos
Éxons , Atrofia Muscular Espinal/genética , Processamento de RNA , Proteína 1 de Sobrevivência do Neurônio Motor/genética , Humanos , Atrofia Muscular Espinal/metabolismo , Sítios de Splice de RNA , Proteína 1 de Sobrevivência do Neurônio Motor/metabolismo , Proteína 2 de Sobrevivência do Neurônio Motor/genética , Proteína 2 de Sobrevivência do Neurônio Motor/metabolismo
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