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1.
Cell ; 181(2): 325-345.e28, 2020 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-32302571

RESUMO

The mechanisms underlying ribonucleoprotein (RNP) granule assembly, including the basis for establishing and maintaining RNP granules with distinct composition, are unknown. One prominent type of RNP granule is the stress granule (SG), a dynamic and reversible cytoplasmic assembly formed in eukaryotic cells in response to stress. Here, we show that SGs assemble through liquid-liquid phase separation (LLPS) arising from interactions distributed unevenly across a core protein-RNA interaction network. The central node of this network is G3BP1, which functions as a molecular switch that triggers RNA-dependent LLPS in response to a rise in intracellular free RNA concentrations. Moreover, we show that interplay between three distinct intrinsically disordered regions (IDRs) in G3BP1 regulates its intrinsic propensity for LLPS, and this is fine-tuned by phosphorylation within the IDRs. Further regulation of SG assembly arises through positive or negative cooperativity by extrinsic G3BP1-binding factors that strengthen or weaken, respectively, the core SG network.


Assuntos
Grânulos Citoplasmáticos/metabolismo , DNA Helicases/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose/metabolismo , RNA Helicases/metabolismo , Proteínas com Motivo de Reconhecimento de RNA/metabolismo , Ribonucleoproteínas/metabolismo , Linhagem Celular Tumoral , Citoplasma/metabolismo , Estruturas Citoplasmáticas/metabolismo , Células HEK293 , Humanos , Fosforilação , RNA/metabolismo
2.
Cell ; 173(3): 677-692.e20, 2018 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-29677512

RESUMO

RNA-binding proteins (RBPs) with prion-like domains (PrLDs) phase transition to functional liquids, which can mature into aberrant hydrogels composed of pathological fibrils that underpin fatal neurodegenerative disorders. Several nuclear RBPs with PrLDs, including TDP-43, FUS, hnRNPA1, and hnRNPA2, mislocalize to cytoplasmic inclusions in neurodegenerative disorders, and mutations in their PrLDs can accelerate fibrillization and cause disease. Here, we establish that nuclear-import receptors (NIRs) specifically chaperone and potently disaggregate wild-type and disease-linked RBPs bearing a NLS. Karyopherin-ß2 (also called Transportin-1) engages PY-NLSs to inhibit and reverse FUS, TAF15, EWSR1, hnRNPA1, and hnRNPA2 fibrillization, whereas Importin-α plus Karyopherin-ß1 prevent and reverse TDP-43 fibrillization. Remarkably, Karyopherin-ß2 dissolves phase-separated liquids and aberrant fibrillar hydrogels formed by FUS and hnRNPA1. In vivo, Karyopherin-ß2 prevents RBPs with PY-NLSs accumulating in stress granules, restores nuclear RBP localization and function, and rescues degeneration caused by disease-linked FUS and hnRNPA2. Thus, NIRs therapeutically restore RBP homeostasis and mitigate neurodegeneration.


Assuntos
Transporte Ativo do Núcleo Celular , Príons/química , Proteínas de Ligação a RNA/química , Receptores Citoplasmáticos e Nucleares/química , Adulto , Idoso , Animais , Citoplasma/química , Proteínas de Ligação a DNA/química , Drosophila melanogaster , Feminino , Proteínas de Fluorescência Verde/química , Células HEK293 , Células HeLa , Homeostase , Humanos , Carioferinas/química , Masculino , Pessoa de Meia-Idade , Chaperonas Moleculares/química , Mutação , Doenças Neurodegenerativas/patologia , Domínios Proteicos , Proteína EWS de Ligação a RNA/química , Fatores Associados à Proteína de Ligação a TATA/química , beta Carioferinas/química
3.
Cell ; 167(3): 774-788.e17, 2016 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-27768896

RESUMO

Expansion of a hexanucleotide repeat GGGGCC (G4C2) in C9ORF72 is the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Transcripts carrying (G4C2) expansions undergo unconventional, non-ATG-dependent translation, generating toxic dipeptide repeat (DPR) proteins thought to contribute to disease. Here, we identify the interactome of all DPRs and find that arginine-containing DPRs, polyGly-Arg (GR) and polyPro-Arg (PR), interact with RNA-binding proteins and proteins with low complexity sequence domains (LCDs) that often mediate the assembly of membrane-less organelles. Indeed, most GR/PR interactors are components of membrane-less organelles such as nucleoli, the nuclear pore complex and stress granules. Genetic analysis in Drosophila demonstrated the functional relevance of these interactions to DPR toxicity. Furthermore, we show that GR and PR altered phase separation of LCD-containing proteins, insinuating into their liquid assemblies and changing their material properties, resulting in perturbed dynamics and/or functions of multiple membrane-less organelles.


Assuntos
Esclerose Lateral Amiotrófica/metabolismo , Dipeptídeos/metabolismo , Demência Frontotemporal/metabolismo , Proteínas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Esclerose Lateral Amiotrófica/genética , Animais , Proteína C9orf72 , Nucléolo Celular/metabolismo , Grânulos Citoplasmáticos/metabolismo , Expansão das Repetições de DNA , Dipeptídeos/genética , Drosophila melanogaster/genética , Demência Frontotemporal/genética , Humanos , Membranas Intracelulares/metabolismo , Poro Nuclear/metabolismo , Peptídeos/genética , Peptídeos/metabolismo , Proteínas/genética
4.
Cell ; 163(1): 123-33, 2015 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-26406374

RESUMO

Stress granules are membrane-less organelles composed of RNA-binding proteins (RBPs) and RNA. Functional impairment of stress granules has been implicated in amyotrophic lateral sclerosis, frontotemporal dementia, and multisystem proteinopathy-diseases that are characterized by fibrillar inclusions of RBPs. Genetic evidence suggests a link between persistent stress granules and the accumulation of pathological inclusions. Here, we demonstrate that the disease-related RBP hnRNPA1 undergoes liquid-liquid phase separation (LLPS) into protein-rich droplets mediated by a low complexity sequence domain (LCD). While the LCD of hnRNPA1 is sufficient to mediate LLPS, the RNA recognition motifs contribute to LLPS in the presence of RNA, giving rise to several mechanisms for regulating assembly. Importantly, while not required for LLPS, fibrillization is enhanced in protein-rich droplets. We suggest that LCD-mediated LLPS contributes to the assembly of stress granules and their liquid properties and provides a mechanistic link between persistent stress granules and fibrillar protein pathology in disease.


Assuntos
Grânulos Citoplasmáticos/química , Grânulos Citoplasmáticos/metabolismo , Agregação Patológica de Proteínas/metabolismo , Amiloide/metabolismo , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Células HeLa , Ribonucleoproteína Nuclear Heterogênea A1 , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/química , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/metabolismo , Humanos
5.
Mol Cell ; 79(4): 645-659.e9, 2020 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-32692974

RESUMO

Stress granules (SGs) are membrane-less ribonucleoprotein condensates that form in response to various stress stimuli via phase separation. SGs act as a protective mechanism to cope with acute stress, but persistent SGs have cytotoxic effects that are associated with several age-related diseases. Here, we demonstrate that the testis-specific protein, MAGE-B2, increases cellular stress tolerance by suppressing SG formation through translational inhibition of the key SG nucleator G3BP. MAGE-B2 reduces G3BP protein levels below the critical concentration for phase separation and suppresses SG initiation. Knockout of the MAGE-B2 mouse ortholog or overexpression of G3BP1 confers hypersensitivity of the male germline to heat stress in vivo. Thus, MAGE-B2 provides cytoprotection to maintain mammalian spermatogenesis, a highly thermosensitive process that must be preserved throughout reproductive life. These results demonstrate a mechanism that allows for tissue-specific resistance against stress and could aid in the development of male fertility therapies.


Assuntos
Grânulos Citoplasmáticos/genética , DNA Helicases/genética , Proteínas de Ligação a Poli-ADP-Ribose/genética , Biossíntese de Proteínas , RNA Helicases/genética , Proteínas com Motivo de Reconhecimento de RNA/genética , Estresse Fisiológico/genética , Regiões 5' não Traduzidas , Animais , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/metabolismo , Grânulos Citoplasmáticos/metabolismo , Grânulos Citoplasmáticos/patologia , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , DNA Helicases/metabolismo , Feminino , Células HCT116 , Células HeLa , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose/metabolismo , RNA Helicases/metabolismo , Proteínas com Motivo de Reconhecimento de RNA/metabolismo , Espermatogônias/citologia , Espermatogônias/patologia , Testículo/citologia , Testículo/metabolismo
6.
Mol Cell ; 74(4): 742-757.e8, 2019 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-30979586

RESUMO

Disturbances in autophagy and stress granule dynamics have been implicated as potential mechanisms underlying inclusion body myopathy (IBM) and related disorders. Yet the roles of core autophagy proteins in IBM and stress granule dynamics remain poorly characterized. Here, we demonstrate that disrupted expression of the core autophagy proteins ULK1 and ULK2 in mice causes a vacuolar myopathy with ubiquitin and TDP-43-positive inclusions; this myopathy is similar to that caused by VCP/p97 mutations, the most common cause of familial IBM. Mechanistically, we show that ULK1/2 localize to stress granules and phosphorylate VCP, thereby increasing VCP's activity and ability to disassemble stress granules. These data suggest that VCP dysregulation and defective stress granule disassembly contribute to IBM-like disease in Ulk1/2-deficient mice. In addition, stress granule disassembly is accelerated by an ULK1/2 agonist, suggesting ULK1/2 as targets for exploiting the higher-order regulation of stress granules for therapeutic intervention of IBM and related disorders.


Assuntos
Proteína Homóloga à Proteína-1 Relacionada à Autofagia/genética , Doenças por Armazenamento dos Lisossomos/genética , Doenças Musculares/genética , Proteínas Serina-Treonina Quinases/genética , Proteína com Valosina/genética , Adenosina Trifosfatases/genética , Animais , Autofagia/genética , Proteínas de Ligação a DNA/genética , Modelos Animais de Doenças , Humanos , Corpos de Inclusão/genética , Corpos de Inclusão/patologia , Doenças por Armazenamento dos Lisossomos/metabolismo , Doenças por Armazenamento dos Lisossomos/patologia , Camundongos , Doenças Musculares/metabolismo , Doenças Musculares/patologia , Fosforilação/genética , Estresse Fisiológico/genética , Ubiquitina/genética
7.
Mol Cell ; 69(6): 965-978.e6, 2018 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-29526694

RESUMO

Under stress, certain eukaryotic proteins and RNA assemble to form membraneless organelles known as stress granules. The most well-studied stress granule components are RNA-binding proteins that undergo liquid-liquid phase separation (LLPS) into protein-rich droplets mediated by intrinsically disordered low-complexity domains (LCDs). Here we show that stress granules include proteasomal shuttle factor UBQLN2, an LCD-containing protein structurally and functionally distinct from RNA-binding proteins. In vitro, UBQLN2 exhibits LLPS at physiological conditions. Deletion studies correlate oligomerization with UBQLN2's ability to phase-separate and form stress-induced cytoplasmic puncta in cells. Using nuclear magnetic resonance (NMR) spectroscopy, we mapped weak, multivalent interactions that promote UBQLN2 oligomerization and LLPS. Ubiquitin or polyubiquitin binding, obligatory for UBQLN2's biological functions, eliminates UBQLN2 LLPS, thus serving as a switch between droplet and disperse phases. We postulate that UBQLN2 LLPS enables its recruitment to stress granules, where its interactions with ubiquitinated substrates reverse LLPS to enable shuttling of clients out of stress granules.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Grânulos Citoplasmáticos/metabolismo , Proteínas Intrinsicamente Desordenadas/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Estresse Fisiológico , Ubiquitinas/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Proteínas Relacionadas à Autofagia , Sítios de Ligação , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/genética , Feminino , Células HeLa , Humanos , Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/genética , Modelos Moleculares , Agregação Patológica de Proteínas , Ligação Proteica , Conformação Proteica , Domínios Proteicos , Dobramento de Proteína , Relação Estrutura-Atividade , Ubiquitinas/química , Ubiquitinas/genética
8.
Artigo em Inglês | MEDLINE | ID: mdl-38336522

RESUMO

BACKGROUND: The association between non-obese or lean nonalcoholic fatty liver disease (NAFLD) and gallbladder polyps (GBPs) has not yet been evaluated. We aimed to determine whether NAFLD is an independent risk factor for the development of GBPs, even in non-obese and lean individuals. METHODS: We analyzed a cohort of 331 208 asymptomatic adults who underwent abdominal ultrasonography (US). The risk of GBP development was evaluated according to the obesity and NAFLD status. RESULTS: The overall prevalence of NAFLD and GBPs ≥ 5 mm was 28.5% and 2.9%, respectively. The prevalence of NAFLD among 160 276 lean, 77 676 overweight and 93 256 obese participants was 8.2%, 31.2%, and 61.1%, respectively. Individuals with NAFLD had a significantly higher incidence of GBPs with a size of ≥ 5 mm [adjusted odds ratio (OR) = 1.18; 95% confidence interval (CI): 1.11-1.25]. A higher body mass index and its categories were also significantly associated with an increased risk of GBPs ≥ 5 mm. Moreover, risk of GBPs ≥ 5 mm was significantly increased even in NAFLD individuals who are not obese (lean: adjusted OR = 1.36, 95% CI: 1.19-1.54; overweight: adjusted OR = 1.14, 95% CI: 1.03-1.26, respectively). CONCLUSIONS: Non-obese/lean NAFLD is an independent risk factor for GBP development, suggesting that NAFLD may play an important role in the pathogenesis of GBPs regardless of the obesity status. Therefore, a more thorough evaluation for GBPs may be necessary when hepatic steatosis is detected on abdominal US, even in non-obese or lean individuals.

9.
Nature ; 544(7650): 367-371, 2017 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-28405022

RESUMO

Amyotrophic lateral sclerosis (ALS) is a rapidly progressing neurodegenerative disease that is characterized by motor neuron loss and that leads to paralysis and death 2-5 years after disease onset. Nearly all patients with ALS have aggregates of the RNA-binding protein TDP-43 in their brains and spinal cords, and rare mutations in the gene encoding TDP-43 can cause ALS. There are no effective TDP-43-directed therapies for ALS or related TDP-43 proteinopathies, such as frontotemporal dementia. Antisense oligonucleotides (ASOs) and RNA-interference approaches are emerging as attractive therapeutic strategies in neurological diseases. Indeed, treatment of a rat model of inherited ALS (caused by a mutation in Sod1) with ASOs against Sod1 has been shown to substantially slow disease progression. However, as SOD1 mutations account for only around 2-5% of ALS cases, additional therapeutic strategies are needed. Silencing TDP-43 itself is probably not appropriate, given its critical cellular functions. Here we present a promising alternative therapeutic strategy for ALS that involves targeting ataxin-2. A decrease in ataxin-2 suppresses TDP-43 toxicity in yeast and flies, and intermediate-length polyglutamine expansions in the ataxin-2 gene increase risk of ALS. We used two independent approaches to test whether decreasing ataxin-2 levels could mitigate disease in a mouse model of TDP-43 proteinopathy. First, we crossed ataxin-2 knockout mice with TDP-43 (also known as TARDBP) transgenic mice. The decrease in ataxin-2 reduced aggregation of TDP-43, markedly increased survival and improved motor function. Second, in a more therapeutically applicable approach, we administered ASOs targeting ataxin-2 to the central nervous system of TDP-43 transgenic mice. This single treatment markedly extended survival. Because TDP-43 aggregation is a component of nearly all cases of ALS, targeting ataxin-2 could represent a broadly effective therapeutic strategy.


Assuntos
Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/terapia , Ataxina-2/deficiência , Proteínas de Ligação a DNA/metabolismo , Longevidade , Oligonucleotídeos Antissenso/uso terapêutico , Agregação Patológica de Proteínas/terapia , Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/fisiopatologia , Animais , Ataxina-2/genética , Sistema Nervoso Central/metabolismo , Grânulos Citoplasmáticos/metabolismo , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Progressão da Doença , Feminino , Técnicas de Silenciamento de Genes , Humanos , Masculino , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Destreza Motora/fisiologia , Oligonucleotídeos Antissenso/administração & dosagem , Oligonucleotídeos Antissenso/genética , Agregação Patológica de Proteínas/genética , Estresse Fisiológico , Análise de Sobrevida
10.
Nature ; 525(7567): 129-33, 2015 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-26308899

RESUMO

The GGGGCC (G4C2) repeat expansion in a noncoding region of C9orf72 is the most common cause of sporadic and familial forms of amyotrophic lateral sclerosis and frontotemporal dementia. The basis for pathogenesis is unknown. To elucidate the consequences of G4C2 repeat expansion in a tractable genetic system, we generated transgenic fly lines expressing 8, 28 or 58 G4C2-repeat-containing transcripts that do not have a translation start site (AUG) but contain an open-reading frame for green fluorescent protein to detect repeat-associated non-AUG (RAN) translation. We show that these transgenic animals display dosage-dependent, repeat-length-dependent degeneration in neuronal tissues and RAN translation of dipeptide repeat (DPR) proteins, as observed in patients with C9orf72-related disease. This model was used in a large-scale, unbiased genetic screen, ultimately leading to the identification of 18 genetic modifiers that encode components of the nuclear pore complex (NPC), as well as the machinery that coordinates the export of nuclear RNA and the import of nuclear proteins. Consistent with these results, we found morphological abnormalities in the architecture of the nuclear envelope in cells expressing expanded G4C2 repeats in vitro and in vivo. Moreover, we identified a substantial defect in RNA export resulting in retention of RNA in the nuclei of Drosophila cells expressing expanded G4C2 repeats and also in mammalian cells, including aged induced pluripotent stem-cell-derived neurons from patients with C9orf72-related disease. These studies show that a primary consequence of G4C2 repeat expansion is the compromise of nucleocytoplasmic transport through the nuclear pore, revealing a novel mechanism of neurodegeneration.


Assuntos
Transporte Ativo do Núcleo Celular/genética , Expansão das Repetições de DNA/genética , Drosophila melanogaster/citologia , Drosophila melanogaster/metabolismo , Fases de Leitura Aberta/genética , Proteínas/genética , Transporte de RNA/genética , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/patologia , Animais , Animais Geneticamente Modificados , Proteína C9orf72 , Drosophila melanogaster/genética , Olho/metabolismo , Feminino , Demência Frontotemporal/genética , Demência Frontotemporal/patologia , Células HeLa , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Masculino , Músculos/citologia , Músculos/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Poro Nuclear/genética , Poro Nuclear/metabolismo , Poro Nuclear/patologia , Fenótipo , Biossíntese de Proteínas , RNA/genética , RNA/metabolismo , Glândulas Salivares/citologia , Glândulas Salivares/metabolismo , Glândulas Salivares/patologia
11.
Sensors (Basel) ; 21(23)2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34884033

RESUMO

A lunar vehicle radiation dosimeter (LVRAD) has been proposed for studying the radiation environment on the lunar surface and evaluating its impact on human health. The LVRAD payload comprises four systems: a particle dosimeter and spectrometer (PDS), a tissue-equivalent dosimeter, a fast neutron spectrometer, and an epithermal neutron spectrometer. A silicon photodiode sensor with compact readout electronics was proposed for the PDS. The PDS system aims to measure protons with 10-100 MeV of energy and assess dose in the lunar space environment. The manufactured silicon photodiode sensor has an effective area of 20 mm × 20 mm and thickness of 650 µm; the electronics consist of an amplifier, analog pulse processor, and a 12-bit analog-to-digital converter for signal readout. We studied the responses of silicon sensors which were manufactured with self-made electronics to gamma rays with a wide range of energies and proton beams.


Assuntos
Dosímetros de Radiação , Silício , Raios gama , Humanos , Nêutrons , Prótons , Radiometria
12.
Am J Gastroenterol ; 115(11): 1840-1848, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33156103

RESUMO

INTRODUCTION: The impact of glycemic status and insulin resistance on the risk of pancreatic cancer in the nondiabetic population remains uncertain. We aimed to examine the association of glycemic status and insulin resistance with pancreatic cancer mortality in individuals with and without diabetes. METHODS: This is a cohort study of 572,021 Korean adults without cancer at baseline, who participated in repeat screening examinations which included fasting blood glucose, hemoglobin A1c, and insulin, and were followed for a median of 8.4 years (interquartile range, 5.3 -13.2 years). Vital status and pancreatic cancer mortality were ascertained through linkage to national death records. RESULTS: During 5,211,294 person-years of follow-up, 260 deaths from pancreatic cancer were identified, with a mortality rate of 5.0 per 10 person-years. In the overall population, the risk of pancreatic cancer mortality increased with increasing levels of glucose and hemoglobin A1c in a dose-response manner, and this association was observed even in individuals without diabetes. In nondiabetic individuals without previously diagnosed or screen-detected diabetes, insulin resistance and hyperinsulinemia were positively associated with increased pancreatic cancer mortality. Specifically, the multivariable-adjusted hazard ratio (95% confidence intervals) for pancreatic cancer mortality comparing the homeostatic model assessment of insulin resistance ≥75th percentile to the <75th percentile was 1.49 (1.08-2.05), and the corresponding hazard ratio comparing the insulin ≥75th percentile to the <75th percentile was 1.43 (1.05-1.95). These associations remained significant when introducing changes in insulin resistance, hyperinsulinemia, and other confounders during follow-up as time-varying covariates. DISCUSSION: Glycemic status, insulin resistance, and hyperinsulinemia, even in individuals without diabetes, were independently associated with an increased risk of pancreatic cancer mortality.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus/metabolismo , Hemoglobinas Glicadas/metabolismo , Hiperinsulinismo/metabolismo , Insulina/metabolismo , Neoplasias Pancreáticas/mortalidade , Estado Pré-Diabético/metabolismo , Adulto , Diabetes Mellitus/epidemiologia , Feminino , Humanos , Hiperinsulinismo/epidemiologia , Resistência à Insulina , Masculino , Pessoa de Meia-Idade , Neoplasias Pancreáticas/epidemiologia , Estado Pré-Diabético/epidemiologia , Modelos de Riscos Proporcionais , República da Coreia/epidemiologia , Fatores de Risco
13.
Nature ; 495(7442): 467-73, 2013 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-23455423

RESUMO

Algorithms designed to identify canonical yeast prions predict that around 250 human proteins, including several RNA-binding proteins associated with neurodegenerative disease, harbour a distinctive prion-like domain (PrLD) enriched in uncharged polar amino acids and glycine. PrLDs in RNA-binding proteins are essential for the assembly of ribonucleoprotein granules. However, the interplay between human PrLD function and disease is not understood. Here we define pathogenic mutations in PrLDs of heterogeneous nuclear ribonucleoproteins (hnRNPs) A2B1 and A1 in families with inherited degeneration affecting muscle, brain, motor neuron and bone, and in one case of familial amyotrophic lateral sclerosis. Wild-type hnRNPA2 (the most abundant isoform of hnRNPA2B1) and hnRNPA1 show an intrinsic tendency to assemble into self-seeding fibrils, which is exacerbated by the disease mutations. Indeed, the pathogenic mutations strengthen a 'steric zipper' motif in the PrLD, which accelerates the formation of self-seeding fibrils that cross-seed polymerization of wild-type hnRNP. Notably, the disease mutations promote excess incorporation of hnRNPA2 and hnRNPA1 into stress granules and drive the formation of cytoplasmic inclusions in animal models that recapitulate the human pathology. Thus, dysregulated polymerization caused by a potent mutant steric zipper motif in a PrLD can initiate degenerative disease. Related proteins with PrLDs should therefore be considered candidates for initiating and perhaps propagating proteinopathies of muscle, brain, motor neuron and bone.


Assuntos
Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/patologia , Demência Frontotemporal/genética , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/química , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/metabolismo , Distrofia Muscular do Cíngulo dos Membros/genética , Proteínas Mutantes/genética , Mutação/genética , Miosite de Corpos de Inclusão/genética , Osteíte Deformante/genética , Príons/química , Sequência de Aminoácidos , Esclerose Lateral Amiotrófica/metabolismo , Animais , Drosophila melanogaster/citologia , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Feminino , Demência Frontotemporal/metabolismo , Demência Frontotemporal/patologia , Células HeLa , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/genética , Humanos , Corpos de Inclusão/genética , Corpos de Inclusão/metabolismo , Corpos de Inclusão/patologia , Masculino , Camundongos , Dados de Sequência Molecular , Distrofia Muscular do Cíngulo dos Membros/metabolismo , Distrofia Muscular do Cíngulo dos Membros/patologia , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Miosite de Corpos de Inclusão/metabolismo , Miosite de Corpos de Inclusão/patologia , Osteíte Deformante/metabolismo , Osteíte Deformante/patologia , Fatores de Terminação de Peptídeos/química , Fatores de Terminação de Peptídeos/genética , Fatores de Terminação de Peptídeos/metabolismo , Príons/genética , Príons/metabolismo , Estrutura Terciária de Proteína/genética , RNA/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
14.
J Korean Med Sci ; 34(30): e208, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31373186

RESUMO

BACKGROUND: Performing transarterial chemoembolization (TACE) is difficult with the occurrence of thrombocytopenia in cirrhotic patients with hepatocellular carcinoma (HCC). We aimed to evaluate the long-term efficacy and safety of partial splenic embolization (PSE) combined with TACE in patients with HCC with severe thrombocytopenia related to splenomegaly. METHODS: We conducted a case-control study consisting of 18 HCC patients with severe thrombocytopenia (< 50 × 109/L) who underwent PSE concurrently with TACE (PSE group) and 72 controls who underwent TACE alone (non-PSE group). RESULTS: Mean platelet counts at 1 month and 1, 3, and 5 years after concurrent PSE and TACE significantly increased compared with baseline (all P < 0.05), whereas the platelet count did not significantly increase after TACE alone. In addition, the platelet count at several time points after treatment in the PSE group was significantly higher than that in the non-PSE group, although the baseline platelet count in the PSE group was significantly lower than that in the non-PSE group. The platelet increase after PSE significantly reduced the need for platelet transfusions (P = 0.040) and enabled the subsequent TACE procedures in time (P = 0.046). The leukocyte counts and hemoglobin concentrations after concurrent PSE and TACE were also significantly increased, without deterioration of Child-Turcotte-Pugh score and unexpected side effects. CONCLUSION: PSE combined with TACE is effective in inducing and maintaining long-term thrombocytopenia improvement which reduces the need for the platelet transfusion and helps to perform initial and serial TACE, and is well-tolerated in patients with HCC and thrombocytopenia. PSE may be a promising treatment option for HCC patients with severe thrombocytopenia associated with splenomegaly who will undergo TACE.


Assuntos
Carcinoma Hepatocelular/terapia , Embolização Terapêutica/métodos , Neoplasias Hepáticas/terapia , Trombocitopenia/diagnóstico , Adulto , Idoso , Carcinoma Hepatocelular/complicações , Carcinoma Hepatocelular/mortalidade , Estudos de Casos e Controles , Quimioembolização Terapêutica , Feminino , Hemoglobinas/análise , Humanos , Contagem de Leucócitos , Neoplasias Hepáticas/complicações , Neoplasias Hepáticas/mortalidade , Masculino , Pessoa de Meia-Idade , Contagem de Plaquetas , Estudos Retrospectivos , Artéria Esplênica/cirurgia , Esplenomegalia/complicações , Esplenomegalia/diagnóstico , Taxa de Sobrevida , Trombocitopenia/complicações
15.
Hum Mol Genet ; 25(5): 936-50, 2016 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-26744327

RESUMO

Adult-onset inherited myopathies with similar pathological features, including hereditary inclusion body myopathy (hIBM) and limb-girdle muscular dystrophy (LGMD), are a genetically heterogeneous group of muscle diseases. It is unclear whether these inherited myopathies initiated by mutations in distinct classes of genes are etiologically related. Here, we exploit a genetic model system to establish a mechanistic link between diseases caused by mutations in two distinct genes, hnRNPA2B1 and DNAJB6. Hrb98DE and mrj are the Drosophila melanogaster homologs of human hnRNPA2B1 and DNAJB6, respectively. We introduced disease-homologous mutations to Hrb98DE, thus capturing mutation-dependent phenotypes in a genetically tractable model system. Ectopic expression of the disease-associated mutant form of hnRNPA2B1 or Hrb98DE in fly muscle resulted in progressive, age-dependent cytoplasmic inclusion pathology, as observed in humans with hnRNPA2B1-related myopathy. Cytoplasmic inclusions consisted of hnRNPA2B1 or Hrb98DE protein in association with the stress granule marker ROX8 and additional endogenous RNA-binding proteins (RBPs), suggesting that these pathological inclusions are related to stress granules. Notably, TDP-43 was also recruited to these cytoplasmic inclusions. Remarkably, overexpression of MRJ rescued this phenotype and suppressed the formation of cytoplasmic inclusions, whereas reduction of endogenous MRJ by a classical loss of function allele enhanced it. Moreover, wild-type, but not disease-associated, mutant forms of MRJ interacted with RBPs after heat shock and prevented their accumulation in aggregates. These results indicate both genetic and physical interactions between disease-linked RBPs and DNAJB6/mrj, suggesting etiologic overlap between the pathogenesis of hIBM and LGMD initiated by mutations in hnRNPA2B1 and DNAJB6.


Assuntos
Contratura/congênito , Drosophila melanogaster/genética , Proteínas de Choque Térmico HSP40/genética , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/genética , Chaperonas Moleculares/genética , Distrofia Muscular do Cíngulo dos Membros/genética , Miosite de Corpos de Inclusão/congênito , Proteínas do Tecido Nervoso/genética , Oftalmoplegia/genética , Adulto , Idade de Início , Sequência de Aminoácidos , Animais , Contratura/genética , Contratura/metabolismo , Contratura/patologia , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Modelos Animais de Doenças , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Regulação da Expressão Gênica , Proteínas de Choque Térmico HSP40/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas/genética , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Humanos , Chaperonas Moleculares/metabolismo , Dados de Sequência Molecular , Músculos/metabolismo , Músculos/patologia , Distrofia Muscular do Cíngulo dos Membros/metabolismo , Distrofia Muscular do Cíngulo dos Membros/patologia , Mutação , Miosite de Corpos de Inclusão/genética , Miosite de Corpos de Inclusão/metabolismo , Miosite de Corpos de Inclusão/patologia , Proteínas do Tecido Nervoso/metabolismo , Oftalmoplegia/metabolismo , Oftalmoplegia/patologia , Fenótipo , Ligação Proteica , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Transdução de Sinais
16.
Acta Neuropathol ; 136(2): 211-226, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29909548

RESUMO

Of nine ependymoma molecular groups detected by DNA methylation profiling, the posterior fossa type A (PFA) is most prevalent. We used DNA methylation profiling to look for further molecular heterogeneity among 675 PFA ependymomas. Two major subgroups, PFA-1 and PFA-2, and nine minor subtypes were discovered. Transcriptome profiling suggested a distinct histogenesis for PFA-1 and PFA-2, but their clinical parameters were similar. In contrast, PFA subtypes differed with respect to age at diagnosis, gender ratio, outcome, and frequencies of genetic alterations. One subtype, PFA-1c, was enriched for 1q gain and had a relatively poor outcome, while patients with PFA-2c ependymomas showed an overall survival at 5 years of > 90%. Unlike other ependymomas, PFA-2c tumors express high levels of OTX2, a potential biomarker for this ependymoma subtype with a good prognosis. We also discovered recurrent mutations among PFA ependymomas. H3 K27M mutations were present in 4.2%, occurring only in PFA-1 tumors, and missense mutations in an uncharacterized gene, CXorf67, were found in 9.4% of PFA ependymomas, but not in other groups. We detected high levels of wildtype or mutant CXorf67 expression in all PFA subtypes except PFA-1f, which is enriched for H3 K27M mutations. PFA ependymomas are characterized by lack of H3 K27 trimethylation (H3 K27-me3), and we tested the hypothesis that CXorf67 binds to PRC2 and can modulate levels of H3 K27-me3. Immunoprecipitation/mass spectrometry detected EZH2, SUZ12, and EED, core components of the PRC2 complex, bound to CXorf67 in the Daoy cell line, which shows high levels of CXorf67 and no expression of H3 K27-me3. Enforced reduction of CXorf67 in Daoy cells restored H3 K27-me3 levels, while enforced expression of CXorf67 in HEK293T and neural stem cells reduced H3 K27-me3 levels. Our data suggest that heterogeneity among PFA ependymomas could have clinicopathologic utility and that CXorf67 may have a functional role in these tumors.


Assuntos
Ependimoma/genética , Regulação Neoplásica da Expressão Gênica/genética , Neoplasias Infratentoriais/genética , Mutação/genética , Proteínas Oncogênicas/genética , Metilação de DNA , Ependimoma/classificação , Ependimoma/patologia , Feminino , Perfilação da Expressão Gênica , Células HEK293 , Histonas/genética , Humanos , Neoplasias Infratentoriais/classificação , Neoplasias Infratentoriais/patologia , Masculino , Transfecção
17.
Liver Int ; 38(8): 1487-1494, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29359396

RESUMO

BACKGROUND & AIMS: The relationship between cigarette smoking and nonalcoholic fatty liver disease (NAFLD) has been controversial. Most relevant studies have relied on self-reported questionnaires. We aimed to elucidate the association between smoking status and NAFLD using an objective biomarker of tobacco exposure (urinary cotinine) and self-reported questionnaire. METHODS: A cross-sectional study was conducted on 160 862 asymptomatic examinees who underwent abdominal ultrasonography and urinary cotinine measurements between April 2011 and December 2015. Cotinine-verified current smokers were defined as participants with urinary cotinine levels ≥50 ng/mL. RESULTS: The mean age of the study population was 36.1 years, and the proportion of men was 51.7%. The proportions of self-reported and cotinine-verified current smokers were 17.6% and 17.7% respectively. After adjusting for confounding factors, self-reported current smoking was associated with an increased risk of NAFLD (adjusted odds ratio [AOR], 1.10; 95% confidence interval [CI], 1.06-1.14). Moreover, among the current smokers, the risk of NAFLD increased with an increase in the amount of cigarette smoking (<10 and ≥10 pack-years vs never smokers; AOR, 1.04 and 1.11; 95% CI, 1.01-1.08 and 1.05-1.16 respectively). Cotinine-verified current smoking was also associated with an increased risk of NAFLD (AOR, 1.10; 95% CI, 1.06-1.14). CONCLUSIONS: Cotinine-verified current smoking and self-reported current smoking were independent risk factors for NAFLD. Further longitudinal studies are needed to more clearly elucidate the impact of smoking on the development of NAFLD.


Assuntos
Fumar Cigarros/efeitos adversos , Fumar Cigarros/epidemiologia , Cotinina/urina , Hepatopatia Gordurosa não Alcoólica/epidemiologia , Hepatopatia Gordurosa não Alcoólica/urina , Adulto , Estudos Transversais , Feminino , Humanos , Modelos Logísticos , Masculino , Análise Multivariada , Fatores de Risco , Autorrelato , Sudão do Sul
18.
Scand J Gastroenterol ; 53(7): 864-869, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30025506

RESUMO

OBJECTIVES: We aimed to examine the relationship between sitting time and the development of ultrasonography-diagnosed gallstone disease (GSD) in young and middle-aged Korean men and women. MATERIAL AND METHODS: We conducted a cohort study of 147,237 participants without GSD at baseline who underwent a health checkup examination between 2011 and 2015 and were followed annually or biennially until December 2016. Sitting time and physical activity were measured using the validated Korean version of the international physical activity questionnaire short form. GSD was defined as either having had a cholecystectomy or having gallstones based on ultrasound. RESULTS: During 486,376 person-years of follow-up, 2382 incident GSD cases were identified. Both prolonged sitting time and inactive physical activity had a significant independent association with the increased risk of GSD. The multivariate-adjusted hazard ratios (95% confidence interval for GSD comparing sitting times of 5-9 and ≥10 h/day with the sitting time of <5 h/day were 1.08 (0.97-1.21) and 1.15 (1.02-1.29), respectively (p for trend = .023). The multivariate-adjusted hazard ratios (95% CIs) for GSD in both the inactive and the minimally active groups compared with HEPA group were 1.22 (1.08-1.38) and 1.13 (0.99-1.28, respectively (p for trend = .001). CONCLUSION: This study demonstrated that sitting time may be associated with GSD risk regardless of physical activity. The findings of this study suggest that both increasing participation in physical activity and reducing sitting time may be independently important in reducing the risk of GSD.


Assuntos
Exercício Físico , Cálculos Biliares/epidemiologia , Comportamento Sedentário , Adulto , Índice de Massa Corporal , Estudos de Coortes , Feminino , Cálculos Biliares/diagnóstico por imagem , Humanos , Masculino , Programas de Rastreamento , Pessoa de Meia-Idade , Análise Multivariada , Modelos de Riscos Proporcionais , República da Coreia/epidemiologia , Fatores de Risco , Fatores de Tempo , Ultrassonografia
19.
J Gastroenterol Hepatol ; 33(7): 1397-1406, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29314222

RESUMO

BACKGROUND AND AIM: The aim of this study is to determine the impact of clinically evident portal hypertension (CEPH) on prognosis of hepatocellular carcinoma (HCC) patients with Child-Pugh A cirrhosis who underwent transarterial chemoembolization (TACE). METHODS: A retrospective data analysis was performed for a total of 388 treatment-naïve HCC patients with Child-Pugh A cirrhosis who underwent TACE as first-line treatment from January 2000 to June 2014. Cumulative occurrence rate of complete response (CR), progression-free survival (PFS), and overall survival (OS) were compared between patients with CEPH and those without CEPH (esophageal/gastric varices or low platelet count [< 100 000 per mm3 ] associated with splenomegaly). RESULTS: Among 388 patients, 252 (64.9%) had CEPH, while 136 (35.1%) had no evidence of CEPH at the time of HCC diagnosis. Cumulative probability of the occurrence of CR was significantly lower in patients with CEPH than that in patients without CEPH (P < 0.001). Median PFS was significantly shorter in patients with CEPH than that in patients without CEPH (5 vs 31 months, P < 0.001). Five-year OS rate was significantly lower in patients with CEPH than that in patients without CEPH (41.5% vs 77.5%, P < 0.001). Multivariate analysis indicated that the presence of CEPH was the most powerful poor prognostic factor for the occurrence of CR (adjusted hazard ratio [aHR], 0.16; 95% confidence interval [CI], 0.09-0.28; P < 0.001), PFS (aHR, 5.01; 95% CI, 3.08-8.12; P < 0.001), and OS (aHR, 2.95; 95% CI, 1.66-5.23; P < 0.001). CONCLUSIONS: The presence of CEPH should be considered as a major negative prognostic factor for patients with HCC who will undergo TACE.


Assuntos
Carcinoma Hepatocelular/terapia , Quimioembolização Terapêutica/métodos , Hipertensão Portal , Neoplasias Hepáticas/terapia , Idoso , Carcinoma Hepatocelular/complicações , Carcinoma Hepatocelular/mortalidade , Intervalo Livre de Doença , Feminino , Humanos , Hipertensão Portal/etiologia , Cirrose Hepática/complicações , Neoplasias Hepáticas/etiologia , Neoplasias Hepáticas/mortalidade , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida
20.
Dig Dis Sci ; 63(10): 2792-2799, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29948568

RESUMO

BACKGROUND: No data are available about the effect of MS on oral nucleos(t)ide analogues (NUCs) treatment and clinical outcomes in chronic hepatitis B (CHB) patients. AIMS: We aimed to elucidate whether coexistence of MS and CHB affects the long-term prognosis of CHB patients with oral NUCs treatment. METHODS: We performed a retrospective data analysis for a total of 587 CHB patients who started oral NUCs treatment for the first time in our institution from January 2006 to March 2016. RESULTS: Among the 587 patients, 70 (11.9%) had MS, but 517 (88.1%) had no evidence of MS when oral NUCs treatment was initiated. Cumulative occurrence rates of viral breakthrough, genotypic resistance, HCC, disease progression (PD), and overall adverse outcomes (OAO) were significantly higher in CHB patients with MS than in those without MS, although HBV-DNA suppression and cumulative occurrence rates of HBeAg negative conversion and seroconversion were not significantly different between the two groups. The overall survival (OS) was also significantly shorter in CHB patients with MS than in those without MS. Multivariate analysis indicated that the MS was an independent, poor prognostic factor for occurrence of genotypic resistance (adjusted hazard ratio [aHR], 22.3; 95% confidence interval [CI] 6.61-75.02; P < 0.001), HCC (aHR, 3.98; 95% CI 2.07-7.66; P < 0.001), PD (aHR, 6.18; 95% CI 3.43-11.14; P < 0.001), OAO (aHR, 8.10; 95% CI 4.68-14.02; P < 0.001), and OS (aHR, 12.29; 95% CI 2.25-67.24; P < 0.001). CONCLUSIONS: MS is an independent determinant of poor prognosis in CHB patients receiving oral NUCs treatment.


Assuntos
Carcinoma Hepatocelular , Hepatite B Crônica , Cirrose Hepática , Síndrome Metabólica/epidemiologia , Nucleosídeos/farmacologia , Adulto , Antivirais/administração & dosagem , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/etiologia , Progressão da Doença , Feminino , Antígenos E da Hepatite B/análise , Hepatite B Crônica/complicações , Hepatite B Crônica/tratamento farmacológico , Hepatite B Crônica/mortalidade , Humanos , Cirrose Hepática/diagnóstico , Cirrose Hepática/etiologia , Masculino , Pessoa de Meia-Idade , República da Coreia/epidemiologia , Medição de Risco , Soroconversão/efeitos dos fármacos , Análise de Sobrevida
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