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1.
Nat Commun ; 12(1): 847, 2021 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-33558503

RESUMO

A large G4C2-repeat expansion in C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Neuronal degeneration associated with this expansion arises from a loss of C9orf72 protein, the accumulation of RNA foci, the expression of dipeptide repeat (DPR) proteins, or all these factors. We report the discovery of a new targeting sequence that is common to all C9orf72 transcripts but enables preferential knockdown of repeat-containing transcripts in multiple cellular models and C9BAC transgenic mice. We optimize stereopure oligonucleotides that act through this site, and we demonstrate that their preferential activity depends on both backbone stereochemistry and asymmetric wing design. In mice, stereopure oligonucleotides produce durable depletion of pathogenic signatures without disrupting protein expression. These oligonucleotides selectively protect motor neurons harboring C9orf72-expansion mutation from glutamate-induced toxicity. We hypothesize that targeting C9orf72 with stereopure oligonucleotides may be a viable therapeutic approach for the treatment of C9orf72-associated neurodegenerative disorders.


Assuntos
Proteína C9orf72/genética , Expansão das Repetições de DNA/genética , Mutação/genética , Oligonucleotídeos/química , Oligonucleotídeos/genética , Esclerose Amiotrófica Lateral/genética , Esclerose Amiotrófica Lateral/patologia , Animais , Proteína C9orf72/química , Éxons/genética , Glutamatos/toxicidade , Íntrons/genética , Camundongos , Neurônios Motores/efeitos dos fármacos , Neurônios Motores/patologia , Processamento de RNA/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Estereoisomerismo
2.
Adv Exp Med Biol ; 1281: 67-76, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33433869

RESUMO

The identification of C9orf72 gene has led to important scientific progresses and has considerably changed our clinical practice. However, a decade after C9orf72 discovery, some important clinical questions remain unsolved. The reliable cutoff for the pathogenic repeat number and the implication of intermediate alleles in frontotemporal dementia, amyotrophic lateral sclerosis, or in other diseases are still uncertain. The occurrence of an anticipation phenomenon - at the clinical and molecular levels - in C9orf72 kindreds is still debated as well, and the factors driving age at onset and phenotype variability are largely unknown. All these questions have a significant impact not only in clinical practice for diagnosis and genetic counseling but also in a research context for the initiation of therapeutic trials. In this chapter, we will address all those issues and summarize the recent updates about clinical aspects of C9orf72 disease, focusing on both the common and the less typical phenotypes.


Assuntos
Esclerose Amiotrófica Lateral , Demência Frontotemporal , Doença de Pick , Esclerose Amiotrófica Lateral/diagnóstico , Esclerose Amiotrófica Lateral/genética , Proteína C9orf72/genética , Expansão das Repetições de DNA/genética , Demência Frontotemporal/diagnóstico , Demência Frontotemporal/genética , Humanos , Proteínas/genética
3.
Adv Exp Med Biol ; 1281: 113-121, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33433872

RESUMO

Around one-third of frontotemporal dementia (FTD) is autosomal dominant with the major genetic causes being mutations in MAPT, GRN and C9orf72. Studying familial forms of FTD can provide a window into the earliest stages of the illness, many years before symptoms start. Large cohort studies have been set up in recent years to better understand this presymptomatic phase, including the Genetic FTD Initiative (GENFI) and the Advancing Research and Treatment for Frontotemporal Lobar Degeneration and Longitudinal Evaluation of Familial Frontotemporal Dementia Subjects (ARTFL/LEFFTDS) studies. Whilst these studies have focused on the investigation of a variety of aspects of genetic FTD, from understanding the molecular pathogenesis to developing biomarkers, they also have a common goal: finding a way to prevent FTD. Researchers from these cohort studies have therefore come together to form the FTD Prevention Initiative (FPI), which has the overarching aim of promoting clinical trials of new therapies to prevent FTD through creating an international database of participants eligible for trials and uniform standards for conducting such trials. This chapter outlines the work of the FPI so far and its future goals over the next few years.


Assuntos
Demência Frontotemporal , Doença de Pick , Proteína C9orf72/genética , Estudos de Coortes , Demência Frontotemporal/genética , Demência Frontotemporal/prevenção & controle , Humanos , Mutação , Proteínas tau/genética
4.
Adv Exp Med Biol ; 1281: 269-282, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33433880

RESUMO

Frontotemporal dementia (FTD) is a neurodegenerative disease with high heritability. Almost half of all familial cases are caused by mutations in one of the three genes MAPT, GRN and C9orf72. Even though major advances in FTD research have been achieved during the last decades, it is not yet fully understood how mutations in these diverse genes lead to the disease. To improve our understanding of FTD, the Risk and Modifying Factors in Frontotemporal Dementia (RiMod-FTD) consortium has created an FTD-specific multi-omics data resource. Using multiple omics technologies on post-mortem brain tissue from patients with mutations in GRN, MAPT or C9orf72 and healthy controls, the resource aims to provide a comprehensive cellular profile of FTD. Furthermore, brain tissue from multiple mouse models and induced pluripotent stem cells (iPSC)-derived neuronal cultures were profiled with similar multi-omics technologies to make up for the shortcomings of post-mortem brain tissue. All data are publicly available to all researchers, and ongoing efforts aim to increase the available datasets and to improve their accessibility. The RiMod-FTD resource represents a uniquely valuable dataset for the field of FTD research, which we hope will accelerate the scientific progress in the field.


Assuntos
Demência Frontotemporal , Doenças Neurodegenerativas , Doença de Pick , Animais , Proteína C9orf72/genética , Demência Frontotemporal/genética , Humanos , Camundongos , Mutação , Proteínas tau/genética
5.
Neurology ; 96(6): e840-e844, 2021 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-33372030

RESUMO

OBJECTIVE: To compare characteristics between Black and White patients with amyotrophic lateral sclerosis (ALS) in order to identify disparities and phenotypic variability. METHODS: We performed database review for patients seen between 1997 and 2020 at the Emory ALS Center in Atlanta, Georgia. Patients with ALS were included for analyses if race was self-reported as Black or White and symptom onset was prior to January 1, 2017. Variables examined include race, age at onset, diagnostic delay, site of onset, median income, C9orf72 mutation status, feeding tube and tracheostomy status, vital capacity, Amyotrophic Lateral Sclerosis Functional Rating Scale-revised(ALSFRS-R) score, and survival time. RESULTS: A total of 2,363 patient records were queried, and 1,298 were included in analysis; 203 self-identified as Black and 1,095 as White. Black patients had younger age at symptom onset, lower frequency of C9orf72 mutations, lower median income, longer diagnostic delay, and lower baseline ALSFRS-R and vital capacity compared to White patients. Black patients had a longer median survival than White patients; however, race was not an independent predictor of survival time when controlling for age at symptom onset, bulbar onset, and C9orf72 positivity. CONCLUSIONS: Black patients with ALS had longer median survival compared to White patients, but race was not independently associated with survival after controlling for age, site of onset, and C9orf72 status, factors known to predict prognosis. Black patients with ALS had longer diagnostic delay and lower baseline ventilatory and functional status at first clinic visit compared to White patients, which could be suggestive of barriers to tertiary care. Further studies are needed to identify the underlying causes of ALS racial differences.


Assuntos
Afro-Americanos/etnologia , Esclerose Amiotrófica Lateral , Diagnóstico Tardio/estatística & dados numéricos , Grupo com Ancestrais do Continente Europeu/etnologia , Acesso aos Serviços de Saúde/estatística & dados numéricos , Disparidades em Assistência à Saúde/estatística & dados numéricos , Fatores Etários , Idade de Início , Idoso , Esclerose Amiotrófica Lateral/diagnóstico , Esclerose Amiotrófica Lateral/etnologia , Esclerose Amiotrófica Lateral/mortalidade , Esclerose Amiotrófica Lateral/fisiopatologia , Proteína C9orf72/genética , Georgia/etnologia , Humanos , Estudos Longitudinais , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos
6.
PLoS Biol ; 18(12): e3001002, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33362237

RESUMO

Nucleocytoplasmic transport (NCT) defects have been implicated in neurodegenerative diseases such as C9ORF72-associated amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD). Here, we identify a neuroprotective pathway of like-Sm protein 12 (LSM12) and exchange protein directly activated by cyclic AMP 1 (EPAC1) that sustains the nucleocytoplasmic RAN gradient and thereby suppresses NCT dysfunction by the C9ORF72-derived poly(glycine-arginine) protein. LSM12 depletion in human neuroblastoma cells aggravated poly(GR)-induced impairment of NCT and nuclear integrity while promoting the nuclear accumulation of poly(GR) granules. In fact, LSM12 posttranscriptionally up-regulated EPAC1 expression, whereas EPAC1 overexpression rescued the RAN gradient and NCT defects in LSM12-deleted cells. C9-ALS patient-derived neurons differentiated from induced pluripotent stem cells (C9-ALS iPSNs) displayed low expression of LSM12 and EPAC1. Lentiviral overexpression of LSM12 or EPAC1 indeed restored the RAN gradient, mitigated the pathogenic mislocalization of TDP-43, and suppressed caspase-3 activation for apoptosis in C9-ALS iPSNs. EPAC1 depletion biochemically dissociated RAN-importin ß1 from the cytoplasmic nuclear pore complex, thereby dissipating the nucleocytoplasmic RAN gradient essential for NCT. These findings define the LSM12-EPAC1 pathway as an important suppressor of the NCT-related pathologies in C9-ALS/FTD.


Assuntos
Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Proteínas de Transporte Nucleocitoplasmático/metabolismo , Proteína ran de Ligação ao GTP/metabolismo , Transporte Ativo do Núcleo Celular , Esclerose Amiotrófica Lateral/genética , Esclerose Amiotrófica Lateral/metabolismo , Esclerose Amiotrófica Lateral/patologia , Proteína C9orf72/genética , Proteína C9orf72/metabolismo , Núcleo Celular/metabolismo , Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/genética , AMP Cíclico/metabolismo , Citoplasma/metabolismo , Demência Frontotemporal/genética , Demência Frontotemporal/metabolismo , Demência Frontotemporal/patologia , Fatores de Troca do Nucleotídeo Guanina/genética , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Poro Nuclear/metabolismo , Proteínas de Transporte Nucleocitoplasmático/genética
7.
Artigo em Russo | MEDLINE | ID: mdl-33081454

RESUMO

OBJECTIVE: To evaluate the frequency of C9orf72-associated frontotemporal dementia (FTD) in the Russian population and to study clinical features of GGGGCC-repeat expansion carriers. MATERIAL AND METHODS: Twenty-eight patients with FTD are included in the study: 15 with a behavioral variant of FTD (bvFTD) and 13 with a agrammatic/non-fluent variant of primary progressive aphasia (avPPA). The mean age was 62 years (34-80), the mean disease duration was 4 years (1-10). The positive family history was noted in 46% of cases. DNA diagnosis was performed using repeat-primed polymerase chain reaction. RESULTS: The frequency of the C9orf72 repeat expansion in patients with FTD was 14%, in patients with bvFTD 20%, in patients with avPPA 8%. The mean age of disease onset in the expansion carriers was 63 (55-75) years. The frequency of the C9orf72 repeats expansion in familial FTD cases was 31%, in sporadic cases 7%. bvFTD with parkinsonian syndrome was noted in two out of four cases, bvFTD with amyotrophic lateral sclerosis (ALS) was shown in one case, avPPA with ALS was shown in one case. One female patient with bvFTD with parkinsonian syndrome presented with cognitive fluctuations that required a differential diagnosis with Lewy body disease. CONCLUSION: This is the first study of the genetic structure of FTD in the Russian population. The prevalence and clinical characteristics of C9orf72-associated FTD were defined, in particular, the spectrum of motor symptoms was shown along with behavioral and aphasic disturbances. DNA diagnosis plays an important role in confirming the diagnosis and selection of patients for potential disease-modifying treatment.


Assuntos
Esclerose Amiotrófica Lateral , Demência Frontotemporal , Adulto , Idoso , Idoso de 80 Anos ou mais , Esclerose Amiotrófica Lateral/diagnóstico , Esclerose Amiotrófica Lateral/epidemiologia , Esclerose Amiotrófica Lateral/genética , Proteína C9orf72/genética , Feminino , Demência Frontotemporal/diagnóstico , Demência Frontotemporal/epidemiologia , Demência Frontotemporal/genética , Humanos , Pessoa de Meia-Idade , Proteínas/genética , Federação Russa/epidemiologia
8.
Proc Natl Acad Sci U S A ; 117(40): 25104-25115, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-32958650

RESUMO

Maintaining the fidelity of nascent peptide chain (NP) synthesis is essential for proteome integrity and cellular health. Ribosome-associated quality control (RQC) serves to resolve stalled translation, during which untemplated Ala/Thr residues are added C terminally to stalled peptide, as shown during C-terminal Ala and Thr addition (CAT-tailing) in yeast. The mechanism and biological effects of CAT-tailing-like activity in metazoans remain unclear. Here we show that CAT-tailing-like modification of poly(GR), a dipeptide repeat derived from amyotrophic lateral sclerosis with frontotemporal dementia (ALS/FTD)-associated GGGGCC (G4C2) repeat expansion in C9ORF72, contributes to disease. We find that poly(GR) can act as a mitochondria-targeting signal, causing some poly(GR) to be cotranslationally imported into mitochondria. However, poly(GR) translation on mitochondrial surface is frequently stalled, triggering RQC and CAT-tailing-like C-terminal extension (CTE). CTE promotes poly(GR) stabilization, aggregation, and toxicity. Our genetic studies in Drosophila uncovered an important role of the mitochondrial protease YME1L in clearing poly(GR), revealing mitochondria as major sites of poly(GR) metabolism. Moreover, the mitochondria-associated noncanonical Notch signaling pathway impinges on the RQC machinery to restrain poly(GR) accumulation, at least in part through the AKT/VCP axis. The conserved actions of YME1L and noncanonical Notch signaling in animal models and patient cells support their fundamental involvement in ALS/FTD.


Assuntos
ATPases Associadas a Diversas Atividades Celulares/genética , Esclerose Amiotrófica Lateral/genética , Proteína C9orf72/genética , Proteínas de Drosophila/genética , Demência Frontotemporal/genética , Metaloendopeptidases/genética , Proteínas Mitocondriais/genética , Proteoma/genética , Receptores Notch/genética , Esclerose Amiotrófica Lateral/metabolismo , Esclerose Amiotrófica Lateral/patologia , Animais , Arginina/genética , Expansão das Repetições de DNA/genética , Modelos Animais de Doenças , Drosophila melanogaster/genética , Demência Frontotemporal/metabolismo , Demência Frontotemporal/patologia , Células HEK293 , Humanos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Biossíntese de Proteínas , Ribossomos/genética , Ribossomos/metabolismo , Transdução de Sinais/genética
10.
Nature ; 585(7824): 251-255, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32848248

RESUMO

Mutation of C9orf72 is the most prevalent defect associated with amyotrophic lateral sclerosis and frontotemporal degeneration1. Together with hexanucleotide-repeat expansion2,3, haploinsufficiency of C9orf72 contributes to neuronal dysfunction4-6. Here we determine the structure of the C9orf72-SMCR8-WDR41 complex by cryo-electron microscopy. C9orf72 and SMCR8 both contain longin and DENN (differentially expressed in normal and neoplastic cells) domains7, and WDR41 is a ß-propeller protein that binds to SMCR8 such that the whole structure resembles an eye slip hook. Contacts between WDR41 and the DENN domain of SMCR8 drive the lysosomal localization of the complex in conditions of amino acid starvation. The structure suggested that C9orf72-SMCR8 is a GTPase-activating protein (GAP), and we found that C9orf72-SMCR8-WDR41 acts as a GAP for the ARF family of small GTPases. These data shed light on the function of C9orf72 in normal physiology, and in amyotrophic lateral sclerosis and frontotemporal degeneration.


Assuntos
Esclerose Amiotrófica Lateral/genética , Proteínas Relacionadas à Autofagia/química , Proteína C9orf72/química , Proteína C9orf72/genética , Proteínas de Transporte/química , Microscopia Crioeletrônica , Demência Frontotemporal/genética , Haploinsuficiência , Complexos Multiproteicos/química , Proteínas Adaptadoras de Transdução de Sinal/química , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Esclerose Amiotrófica Lateral/metabolismo , Proteínas Relacionadas à Autofagia/deficiência , Proteínas Relacionadas à Autofagia/metabolismo , Proteínas Relacionadas à Autofagia/ultraestrutura , Proteína C9orf72/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Transporte/ultraestrutura , Demência Frontotemporal/metabolismo , Humanos , Lisossomos/metabolismo , Modelos Moleculares , Complexos Multiproteicos/genética , Complexos Multiproteicos/metabolismo , Complexos Multiproteicos/ultraestrutura , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Mutação , Domínios Proteicos
11.
PLoS One ; 15(8): e0233247, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32857759

RESUMO

Poly(glycine-alanine) (polyGA) is one of the polydipeptides expressed in Frontotemporal Dementia and/or Amyotrophic Lateral Sclerosis 1 caused by C9ORF72 mutations and accumulates as inclusion bodies in the brain of patients. Superficially these inclusions are similar to those formed by polyglutamine (polyQ)-expanded Huntingtin exon 1 (Httex1) in Huntington's disease. Both have been reported to form an amyloid-like structure suggesting they might aggregate via similar mechanisms and therefore recruit the same repertoire of endogenous proteins. When co-expressed in the same cell, polyGA101 and Httex1(Q97) inclusions adopted immiscible phases suggesting different endogenous proteins would be enriched. Proteomic analyses identified 822 proteins in the inclusions. Only 7 were specific to polyGA and 4 specific to Httex1(Q97). Quantitation demonstrated distinct enrichment patterns for the proteins not specific to each inclusion type (up to ~8-fold normalized to total mass). The proteasome, microtubules, TriC chaperones, and translational machinery were enriched in polyGA aggregates, whereas Dnaj chaperones, nuclear envelope and RNA splicing proteins were enriched in Httex1(Q97) aggregates. Both structures revealed a collection of folding and degradation machinery including proteins in the Httex1(Q97) aggregates that are risk factors for other neurodegenerative diseases involving protein aggregation when mutated, which suggests a convergence point in the pathomechanisms of these diseases.


Assuntos
Corpos de Inclusão/metabolismo , Peptídeos/metabolismo , Proteínas/metabolismo , Animais , Proteína C9orf72/genética , Proteína C9orf72/metabolismo , Linhagem Celular , Éxons , Humanos , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Corpos de Inclusão/genética , Corpos de Inclusão/patologia , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Camundongos , Microscopia Confocal , Mutação , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Peptídeos/genética , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/metabolismo , Agregação Patológica de Proteínas/patologia , Proteínas/genética , Proteólise , Proteoma/genética , Proteoma/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Fatores de Risco , Solubilidade
12.
Nature ; 585(7823): 96-101, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32814898

RESUMO

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are neurodegenerative disorders that overlap in their clinical presentation, pathology and genetic origin. Autoimmune disorders are also overrepresented in both ALS and FTD, but this remains an unexplained epidemiologic observation1-3. Expansions of a hexanucleotide repeat (GGGGCC) in the C9orf72 gene are the most common cause of familial ALS and FTD (C9-ALS/FTD), and lead to both repeat-containing RNA and dipeptide accumulation, coupled with decreased C9orf72 protein expression in brain and peripheral blood cells4-6. Here we show in mice that loss of C9orf72 from myeloid cells alone is sufficient to recapitulate the age-dependent lymphoid hypertrophy and autoinflammation seen in animals with a complete knockout of C9orf72. Dendritic cells isolated from C9orf72-/- mice show marked early activation of the type I interferon response, and C9orf72-/- myeloid cells are selectively hyperresponsive to activators of the stimulator of interferon genes (STING) protein-a key regulator of the innate immune response to cytosolic DNA. Degradation of STING through the autolysosomal pathway is diminished in C9orf72-/- myeloid cells, and blocking STING suppresses hyperactive type I interferon responses in C9orf72-/- immune cells as well as splenomegaly and inflammation in C9orf72-/- mice. Moreover, mice lacking one or both copies of C9orf72 are more susceptible to experimental autoimmune encephalitis, mirroring the susceptibility to autoimmune diseases seen in people with C9-ALS/FTD. Finally, blood-derived macrophages, whole blood and brain tissue from patients with C9-ALS/FTD all show an elevated type I interferon signature compared with samples from people with sporadic ALS/FTD; this increased interferon response can be suppressed with a STING inhibitor. Collectively, our results suggest that patients with C9-ALS/FTD have an altered immunophenotype because their reduced levels of C9orf72 cannot suppress the inflammation mediated by the induction of type I interferons by STING.


Assuntos
Proteína C9orf72/genética , Proteína C9orf72/metabolismo , Inflamação/metabolismo , Inflamação/prevenção & controle , Proteínas de Membrana/metabolismo , Células Mieloides/metabolismo , Envelhecimento/imunologia , Esclerose Amiotrófica Lateral/genética , Animais , Proteína C9orf72/deficiência , Células Dendríticas/citologia , Células Dendríticas/imunologia , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/imunologia , Feminino , Humanos , Inflamação/genética , Inflamação/imunologia , Interferon Tipo I/biossíntese , Interferon Tipo I/imunologia , Proteínas de Membrana/antagonistas & inibidores , Camundongos , Células Mieloides/imunologia , Neoplasias/imunologia , Linfócitos T/citologia , Linfócitos T/imunologia
13.
Nat Commun ; 11(1): 3354, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620797

RESUMO

Expansion of an intronic (GGGGCC)n repeat region within the C9orf72 gene is a main cause of familial amyotrophic lateral sclerosis and frontotemporal dementia (c9ALS/FTD). A hallmark of c9ALS/FTD is the accumulation of misprocessed RNAs, which are often targets of cellular RNA surveillance. Here, we show that RNA decay mechanisms involving upstream frameshift 1 (UPF1), including nonsense-mediated decay (NMD), are inhibited in c9ALS/FTD brains and in cultured cells expressing either of two arginine-rich dipeptide repeats (R-DPRs), poly(GR) and poly(PR). Mechanistically, although R-DPRs cause the recruitment of UPF1 to stress granules, stress granule formation is independent of NMD inhibition. Instead, NMD inhibition is primarily a result from global translational repression caused by R-DPRs. Overexpression of UPF1, but none of its NMD-deficient mutants, enhanced the survival of neurons treated by R-DPRs, suggesting that R-DPRs cause neurotoxicity in part by inhibiting cellular RNA surveillance.


Assuntos
Esclerose Amiotrófica Lateral/genética , Proteína C9orf72/genética , Demência Frontotemporal/genética , Degradação do RNAm Mediada por Códon sem Sentido , RNA Helicases/metabolismo , Transativadores/metabolismo , Esclerose Amiotrófica Lateral/patologia , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Expansão das Repetições de DNA , Conjuntos de Dados como Assunto , Embrião de Mamíferos , Feminino , Lobo Frontal/patologia , Demência Frontotemporal/patologia , Humanos , Íntrons/genética , Camundongos , Neurônios/metabolismo , Neurônios/patologia , Cultura Primária de Células , Biossíntese de Proteínas , RNA Mensageiro/metabolismo , RNA-Seq , Transativadores/genética
14.
Neuron ; 107(6): 1124-1140.e11, 2020 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-32673563

RESUMO

Through mechanisms that remain poorly defined, defects in nucleocytoplasmic transport and accumulations of specific nuclear-pore-complex-associated proteins have been reported in multiple neurodegenerative diseases, including C9orf72 Amyotrophic Lateral Sclerosis and Frontotemporal Dementia (ALS/FTD). Using super-resolution structured illumination microscopy, we have explored the mechanism by which nucleoporins are altered in nuclei isolated from C9orf72 induced pluripotent stem-cell-derived neurons (iPSNs). Of the 23 nucleoporins evaluated, we observed a reduction in a subset of 8, including key components of the nuclear pore complex scaffold and the transmembrane nucleoporin POM121. Reduction in POM121 appears to initiate a decrease in the expression of seven additional nucleoporins, ultimately affecting the localization of Ran GTPase and subsequent cellular toxicity in C9orf72 iPSNs. Collectively, our data suggest that the expression of expanded C9orf72 ALS/FTD repeat RNA alone affects nuclear POM121 expression in the initiation of a pathological cascade affecting nucleoporin levels within neuronal nuclei and ultimately downstream neuronal survival.


Assuntos
Esclerose Amiotrófica Lateral/metabolismo , Proteína C9orf72/genética , Demência Frontotemporal/metabolismo , Glicoproteínas de Membrana/genética , Complexo de Proteínas Formadoras de Poros Nucleares/genética , Transporte Ativo do Núcleo Celular , Esclerose Amiotrófica Lateral/genética , Proteína C9orf72/metabolismo , Células Cultivadas , Demência Frontotemporal/genética , Células HEK293 , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Glicoproteínas de Membrana/metabolismo , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Poro Nuclear/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo
15.
Proc Natl Acad Sci U S A ; 117(31): 18591-18599, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32690681

RESUMO

Repeat associated non-AUG (RAN) translation is found in a growing number of microsatellite expansion diseases, but the mechanisms remain unclear. We show that RAN translation is highly regulated by the double-stranded RNA-dependent protein kinase (PKR). In cells, structured CAG, CCUG, CAGG, and G4C2 expansion RNAs activate PKR, which leads to increased levels of multiple RAN proteins. Blocking PKR using PKR-K296R, the TAR RNA binding protein or PKR-KO cells, reduces RAN protein levels. p-PKR is elevated in C9orf72 ALS/FTD human and mouse brains, and inhibiting PKR in C9orf72 BAC transgenic mice using AAV-PKR-K296R or the Food and Drug Administration (FDA)-approved drug metformin, decreases RAN proteins, and improves behavior and pathology. In summary, targeting PKR, including by use of metformin, is a promising therapeutic approach for C9orf72 ALS/FTD and other expansion diseases.


Assuntos
Esclerose Amiotrófica Lateral/metabolismo , Proteína C9orf72 , Metformina/farmacologia , Biossíntese de Proteínas/efeitos dos fármacos , eIF-2 Quinase , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Proteína C9orf72/genética , Proteína C9orf72/metabolismo , Modelos Animais de Doenças , Demência Frontotemporal/metabolismo , Humanos , Camundongos , Camundongos Transgênicos , Repetições de Microssatélites/genética , eIF-2 Quinase/genética , eIF-2 Quinase/metabolismo
16.
Nature ; 582(7810): 89-94, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32483373

RESUMO

A hexanucleotide-repeat expansion in C9ORF72 is the most common genetic variant that contributes to amyotrophic lateral sclerosis and frontotemporal dementia1,2. The C9ORF72 mutation acts through gain- and loss-of-function mechanisms to induce pathways that are implicated in neural degeneration3-9. The expansion is transcribed into a long repetitive RNA, which negatively sequesters RNA-binding proteins5 before its non-canonical translation into neural-toxic dipeptide proteins3,4. The failure of RNA polymerase to read through the mutation also reduces the abundance of the endogenous C9ORF72 gene product, which functions in endolysosomal pathways and suppresses systemic and neural inflammation6-9. Notably, the effects of the repeat expansion act with incomplete penetrance in families with a high prevalence of amyotrophic lateral sclerosis or frontotemporal dementia, indicating that either genetic or environmental factors modify the risk of disease for each individual. Identifying disease modifiers is of considerable translational interest, as it could suggest strategies to diminish the risk of developing amyotrophic lateral sclerosis or frontotemporal dementia, or to slow progression. Here we report that an environment with reduced abundance of immune-stimulating bacteria10,11 protects C9orf72-mutant mice from premature mortality and significantly ameliorates their underlying systemic inflammation and autoimmunity. Consistent with C9orf72 functioning to prevent microbiota from inducing a pathological inflammatory response, we found that reducing the microbial burden in mutant mice with broad spectrum antibiotics-as well as transplanting gut microflora from a protective environment-attenuated inflammatory phenotypes, even after their onset. Our studies provide further evidence that the microbial composition of our gut has an important role in brain health and can interact in surprising ways with well-known genetic risk factors for disorders of the nervous system.


Assuntos
Proteína C9orf72/genética , Microbioma Gastrointestinal/fisiologia , Gliose/microbiologia , Gliose/patologia , Inflamação/genética , Inflamação/microbiologia , Medula Espinal/patologia , Esclerose Amiotrófica Lateral/genética , Esclerose Amiotrófica Lateral/patologia , Animais , Antibacterianos/farmacologia , Autoimunidade/efeitos dos fármacos , Autoimunidade/genética , Autoimunidade/imunologia , Movimento Celular/efeitos dos fármacos , Citocinas/imunologia , Transplante de Microbiota Fecal , Feminino , Demência Frontotemporal/genética , Demência Frontotemporal/patologia , Microbioma Gastrointestinal/efeitos dos fármacos , Microbioma Gastrointestinal/imunologia , Gliose/genética , Gliose/prevenção & controle , Inflamação/patologia , Inflamação/prevenção & controle , Mutação com Perda de Função/genética , Masculino , Camundongos , Microglia/imunologia , Microglia/microbiologia , Microglia/patologia , Medula Espinal/imunologia , Medula Espinal/microbiologia , Taxa de Sobrevida
18.
Neurology ; 94(24): e2592-e2604, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32414878

RESUMO

OBJECTIVE: To understand the progressive nature of amyotrophic lateral sclerosis (ALS) by investigating differential brain patterns of gray and white matter involvement in clinically or genetically defined subgroups of patients using cross-sectional, longitudinal, and multimodal MRI. METHODS: We assessed cortical thickness, subcortical volumes, and white matter connectivity from T1-weighted and diffusion-weighted MRI in 292 patients with ALS (follow-up: n = 150) and 156 controls (follow-up: n = 72). Linear mixed-effects models were used to assess changes in structural brain measurements over time in patients compared to controls. RESULTS: Patients with a C9orf72 mutation (n = 24) showed widespread gray and white matter involvement at baseline, and extensive loss of white matter integrity in the connectome over time. In C9orf72-negative patients, we detected cortical thinning of motor and frontotemporal regions, and loss of white matter integrity of connections linked to the motor cortex. Patients with spinal onset displayed widespread white matter involvement at baseline and gray matter atrophy over time, whereas patients with bulbar onset started out with prominent gray matter involvement. Patients with unaffected cognition or behavior displayed predominantly motor system involvement, while widespread cerebral changes, including frontotemporal regions with progressive white matter involvement over time, were associated with impaired behavior or cognition. Progressive loss of gray and white matter integrity typically occurred in patients with shorter disease durations (<13 months), independent of progression rate. CONCLUSIONS: Heterogeneity of phenotype and C9orf72 genotype relates to distinct patterns of cerebral degeneration. We demonstrate that imaging studies have the potential to monitor disease progression and early intervention may be required to limit cerebral degeneration.


Assuntos
Esclerose Amiotrófica Lateral/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Idoso , Esclerose Amiotrófica Lateral/genética , Esclerose Amiotrófica Lateral/patologia , Comportamento , Encéfalo/patologia , Proteína C9orf72/genética , Cognição , Estudos Transversais , Imagem de Difusão por Ressonância Magnética , Progressão da Doença , Feminino , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/patologia , Humanos , Estudos Longitudinais , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Imagem Multimodal , Mutação , Estudos Prospectivos , Substância Branca/diagnóstico por imagem , Substância Branca/patologia
19.
Neuron ; 107(2): 292-305.e6, 2020 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-32375063

RESUMO

GGGGCC hexanucleotide repeat expansions (HREs) in C9orf72 cause amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) and lead to the production of aggregating dipeptide repeat proteins (DPRs) via repeat associated non-AUG (RAN) translation. Here, we show the similar intronic GGCCTG HREs that causes spinocerebellar ataxia type 36 (SCA36) is also translated into DPRs, including poly(GP) and poly(PR). We demonstrate that poly(GP) is more abundant in SCA36 compared to c9ALS/FTD patient tissue due to canonical AUG-mediated translation from intron-retained GGCCTG repeat RNAs. However, the frequency of the antisense RAN translation product poly(PR) is comparable between c9ALS/FTD and SCA36 patient samples. Interestingly, in SCA36 patient tissue, poly(GP) exists as a soluble species, and no TDP-43 pathology is present. We show that aggregate-prone chimeric DPR (cDPR) species underlie the divergent DPR pathology between c9ALS/FTD and SCA36. These findings reveal key differences in translation, solubility, and protein aggregation of DPRs between c9ALS/FTD and SCA36.


Assuntos
Esclerose Amiotrófica Lateral/genética , Proteína C9orf72/genética , Dipeptídeos/genética , Demência Frontotemporal/genética , Proteínas Mutantes Quiméricas/genética , Ataxias Espinocerebelares/genética , Sequência de Aminoácidos , Animais , Animais Recém-Nascidos , Elementos Antissenso (Genética)/genética , Expansão das Repetições de DNA , Feminino , Humanos , Íntrons/genética , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , Sequências Repetitivas de Ácido Nucleico
20.
J Pathol ; 251(3): 262-271, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32391572

RESUMO

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease. The majority of cases are sporadic (sALS), while the most common inherited form is due to C9orf72 mutation (C9ALS). A high burden of inclusion pathology is seen in glia (including oligodendrocytes) in ALS, especially in C9ALS. Myelin basic protein (MBP) messenger RNA (mRNA) must be transported to oligodendrocyte processes for myelination, a possible vulnerability for normal function. TDP43 is found in pathological inclusions in ALS and is a component of mRNA transport granules. Thus, TDP43 aggregation could lead to MBP loss. Additionally, the hexanucleotide expansion of mutant C9ALS binds hnRNPA2/B1, a protein essential for mRNA transport, causing potential further impairment of hnRNPA2/B1 function, and thus myelination. Using immunohistochemistry for p62 and TDP43 in human post-mortem tissue, we found a high burden of glial inclusions in the prefrontal cortex, precentral gyrus, and spinal cord in ALS, which was greater in C9ALS than in sALS cases. Double staining demonstrated that the majority of these inclusions were in oligodendrocytes. Using immunoblotting, we demonstrated reduced MBP protein levels relative to PLP (a myelin component that relies on protein not mRNA transport) and neurofilament protein (an axonal marker) in the spinal cord. This MBP loss was disproportionate to the level of PLP and axonal loss, suggesting that impaired mRNA transport may be partly responsible. Finally, we show that in C9ALS cases, the level of oligodendroglial inclusions correlates inversely with levels of hnRNPA2/B1 and the number of oligodendrocyte precursor cells. We conclude that there is considerable oligodendrocyte pathology in ALS, which at least partially reflects impairment of mRNA transport. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.


Assuntos
Esclerose Amiotrófica Lateral/patologia , Axônios/patologia , Oligodendroglia/patologia , Tratos Piramidais/patologia , Substância Branca/patologia , Esclerose Amiotrófica Lateral/genética , Esclerose Amiotrófica Lateral/metabolismo , Autopsia , Axônios/química , Biomarcadores/análise , Proteína C9orf72/genética , Estudos de Casos e Controles , Proteínas de Ligação a DNA/análise , Predisposição Genética para Doença , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/análise , Humanos , Mutação , Proteína Básica da Mielina/análise , Oligodendroglia/química , Fenótipo , Tratos Piramidais/química , Transporte de RNA , RNA Mensageiro/metabolismo , Proteína Sequestossoma-1/análise , Fatores de Transcrição/análise , Substância Branca/química
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