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1.
Am J Hum Genet ; 108(10): 2017-2023, 2021 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-34587489

RESUMO

ABHD16A (abhydrolase domain-containing protein 16A, phospholipase) encodes the major phosphatidylserine (PS) lipase in the brain. PS lipase synthesizes lysophosphatidylserine, an important signaling lipid that functions in the mammalian central nervous system. ABHD16A has not yet been associated with a human disease. In this report, we present a cohort of 11 affected individuals from six unrelated families with a complicated form of hereditary spastic paraplegia (HSP) who carry bi-allelic deleterious variants in ABHD16A. Affected individuals present with a similar phenotype consisting of global developmental delay/intellectual disability, progressive spasticity affecting the upper and lower limbs, and corpus callosum and white matter anomalies. Immunoblot analysis on extracts from fibroblasts from four affected individuals demonstrated little to no ABHD16A protein levels compared to controls. Our findings add ABHD16A to the growing list of lipid genes in which dysregulation can cause complicated forms of HSP and begin to describe the molecular etiology of this condition.


Assuntos
Paralisia Cerebral/patologia , Deficiência Intelectual/patologia , Leucoencefalopatias/patologia , Monoacilglicerol Lipases/genética , Mutação , Paraplegia Espástica Hereditária/patologia , Adolescente , Adulto , Paralisia Cerebral/etiologia , Paralisia Cerebral/metabolismo , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Deficiência Intelectual/etiologia , Deficiência Intelectual/metabolismo , Leucoencefalopatias/etiologia , Leucoencefalopatias/metabolismo , Masculino , Monoacilglicerol Lipases/deficiência , Linhagem , Fenótipo , Paraplegia Espástica Hereditária/etiologia , Paraplegia Espástica Hereditária/metabolismo , Adulto Jovem
2.
Cells ; 10(8)2021 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-34440627

RESUMO

Translation initiation factor 2B (eIF2B) is a master regulator of global protein synthesis in all cell types. The mild genetic Eif2b5(R132H) mutation causes a slight reduction in eIF2B enzymatic activity which leads to abnormal composition of mitochondrial electron transfer chain complexes and impaired oxidative phosphorylation. Previous work using primary fibroblasts isolated from Eif2b5(R132H/R132H) mice revealed that owing to increased mitochondrial biogenesis they exhibit normal cellular ATP level. In contrast to fibroblasts, here we show that primary astrocytes isolated from Eif2b5(R132H/R132H) mice are unable to compensate for their metabolic impairment and exhibit chronic state of low ATP level regardless of extensive adaptation efforts. Mutant astrocytes are hypersensitive to oxidative stress and to further energy stress. Moreover, they show migration deficit upon exposure to glucose starvation. The mutation in Eif2b5 prompts reactive oxygen species (ROS)-mediated inferior ability to stimulate the AMP-activated protein kinase (AMPK) axis, due to a requirement to increase the mammalian target of rapamycin complex-1 (mTORC1) signalling in order to enable oxidative glycolysis and generation of specific subclass of ROS-regulating proteins, similar to cancer cells. The data disclose the robust impact of eIF2B on metabolic and redox homeostasis programs in astrocytes and point at their hyper-sensitivity to mutated eIF2B. Thereby, it illuminates the central involvement of astrocytes in Vanishing White Matter Disease (VWMD), a genetic neurodegenerative leukodystrophy caused by homozygous hypomorphic mutations in genes encoding any of the 5 subunits of eIF2B.


Assuntos
Trifosfato de Adenosina/metabolismo , Astrócitos/metabolismo , Encéfalo/metabolismo , Metabolismo Energético , Fator de Iniciação 2B em Eucariotos/metabolismo , Leucoencefalopatias/metabolismo , Mitocôndrias/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Apoptose , Astrócitos/patologia , Encéfalo/patologia , Movimento Celular , Células Cultivadas , Modelos Animais de Doenças , Fator de Iniciação 2B em Eucariotos/genética , Leucoencefalopatias/genética , Leucoencefalopatias/patologia , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Mitocôndrias/genética , Mitocôndrias/patologia , Mutação , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais
3.
Int J Mol Sci ; 22(5)2021 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-33800130

RESUMO

Vanishing white matter (VWM) disease is a genetic leukodystrophy leading to severe neurological disease and early death. VWM is caused by bi-allelic mutations in any of the five genes encoding the subunits of the eukaryotic translation factor 2B (EIF2B). Previous studies have attempted to investigate the molecular mechanism of VWN by constructing models for each subunit of EIF2B that causes VWM disease. The underlying molecular mechanisms of the way in which mutations in EIF2B3 result in VWM are largely unknown. Based on our recent results, we generated an eif2b3 knockout (eif2b3-/-) zebrafish model and performed quantitative proteomic analysis between the wild-type (WT) and eif2b3-/- zebrafish, and identified 25 differentially expressed proteins. Four proteins were significantly upregulated, and 21 proteins were significantly downregulated in eif2b3-/- zebrafish compared to WT. Lon protease and the neutral amino acid transporter SLC1A4 were significantly increased in eif2b3-/- zebrafish, and crystallin proteins were significantly decreased. The differential expression of proteins was confirmed by the evaluation of mRNA levels in eif2b3-/- zebrafish, using whole-mount in situ hybridization analysis. This study identified proteins which candidates as key regulators of the progression of VWN disease, using quantitative proteomic analysis in the first EIF2B3 animal model of VWN disease.


Assuntos
Sistema ASC de Transporte de Aminoácidos/metabolismo , Leucoencefalopatias/metabolismo , Proteoma/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/metabolismo , Sistema ASC de Transporte de Aminoácidos/genética , Animais , Animais Geneticamente Modificados , Modelos Animais de Doenças , Fator de Iniciação 2B em Eucariotos/deficiência , Fator de Iniciação 2B em Eucariotos/metabolismo , Humanos , Leucoencefalopatias/genética , Leucoencefalopatias/patologia , Proteoma/genética , Proteômica , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética
4.
Nat Commun ; 12(1): 2344, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33879794

RESUMO

Direct determination of RNA structures and interactions in living cells is critical for understanding their functions in normal physiology and disease states. Here, we present PARIS2, a dramatically improved method for RNA duplex determination in vivo with >4000-fold higher efficiency than previous methods. PARIS2 captures ribosome binding sites on mRNAs, reporting translation status on a transcriptome scale. Applying PARIS2 to the U8 snoRNA mutated in the neurological disorder LCC, we discover a network of dynamic RNA structures and interactions which are destabilized by patient mutations. We report the first whole genome structure of enterovirus D68, an RNA virus that causes polio-like symptoms, revealing highly dynamic conformations altered by antiviral drugs and different pathogenic strains. We also discover a replication-associated asymmetry on the (+) and (-) strands of the viral genome. This study establishes a powerful technology for efficient interrogation of the RNA structurome and interactome in human diseases.


Assuntos
Doenças Transmissíveis/genética , Doenças Transmissíveis/metabolismo , Doenças Genéticas Inatas/genética , Doenças Genéticas Inatas/metabolismo , Fotoquímica/métodos , RNA/química , RNA/metabolismo , Calcinose/genética , Calcinose/metabolismo , Cistos do Sistema Nervoso Central/genética , Cistos do Sistema Nervoso Central/metabolismo , Reagentes para Ligações Cruzadas , Enterovirus Humano D/genética , Furocumarinas , Genoma Viral , Humanos , Leucoencefalopatias/genética , Leucoencefalopatias/metabolismo , Modelos Moleculares , Mutação , Conformação de Ácido Nucleico , Processos Fotoquímicos , RNA/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Nucleolar Pequeno/química , RNA Nucleolar Pequeno/genética , RNA Nucleolar Pequeno/metabolismo , RNA Viral/química , RNA Viral/genética
5.
Cerebrovasc Dis ; 50(3): 347-355, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33730735

RESUMO

INTRODUCTION: Sodium MRI (23Na MRI) derived biomarkers such as tissue sodium concentration (TSC) provide valuable information on cell function and brain tissue viability and has become a reliable tool for the assessment of brain tumors and ischemic stroke beyond pathoanatomical morphology. Patients with major stroke often suffer from different degrees of underlying white matter lesions (WMLs) attributed to chronic small vessel disease. This study aimed to evaluate the WM TSC in patients with an acute ischemic stroke and to correlate the TSC with the extent of small vessel disease. Furthermore, the reliability of relative TSC (rTSC) compared to absolute TSC in these patients was analyzed. METHODOLOGY: We prospectively examined 62 patients with acute ischemic stroke (73 ± 13 years) between November 2016 and August 2019 from which 18 patients were excluded and thus 44 patients were evaluated. A 3D 23Na MRI was acquired in addition to a T2-TIRM and a diffusion-weighted image. Coregistration and segmentation were performed with SPM 12 based on the T2-TIRM image. The extension of WM T2 hyperintense lesions in each patient was classified using the Fazekas scale of WMLs. The absolute TSC in the WM region was correlated to the Fazekas grades. The stroke region was manually segmented on the coregistered absolute diffusion coefficient image and absolute, and rTSC was calculated in the stroke region and compared to nonischemic WM region. Statistical significance was evaluated using the Student t-test. RESULTS: For patients with Fazekas grade I (n = 25, age: 68.5 ± 15.1 years), mean TSC in WM was 55.57 ± 7.43 mM, and it was not statistically significant different from patients with Fazekas grade II (n = 7, age: 77.9 ± 6.4 years) with a mean TSC in WM of 53.9 ± 6.4 mM, p = 0.58. For patients with Fazekas grade III (n = 9, age: 81.4 ± 7.9 years), mean TSC in WM was 68.7 ± 10.5 mM, which is statistically significantly higher than the TSC in patients with Fazekas grade I and II (p < 0.001 and p = 0.05, respectively). There was a positive correlation between the TSC in WM and the Fazekas grade with r = 0.48 p < 0.001. The rTSC in the stroke region was statistically significant difference between low (0 and I) and high (2 and 3) Fazekas grades (p = 0.0353) whereas there was no statistically significant difference in absolute TSC in the stroke region between low (0 and I) and high (2 and 3) Fazekas grades. CONCLUSION: The significant difference in absolute TSC in WM in patients with severe small vessel disease; Fazekas grade 3 can lead to inaccuracies using rTSC quantification for evaluation of acute ischemic stroke using 23 Na MRI. The study, therefore, emphasizes the importance of absolute tissue sodium quantification.


Assuntos
Doenças de Pequenos Vasos Cerebrais/diagnóstico por imagem , AVC Isquêmico/diagnóstico por imagem , Leucoencefalopatias/diagnóstico por imagem , Imageamento por Ressonância Magnética , Isótopos de Sódio/metabolismo , Substância Branca/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Doenças de Pequenos Vasos Cerebrais/metabolismo , Imagem de Difusão por Ressonância Magnética , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , AVC Isquêmico/metabolismo , Leucoencefalopatias/metabolismo , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Reprodutibilidade dos Testes , Substância Branca/metabolismo
6.
J Cell Mol Med ; 25(9): 4516-4521, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33783963

RESUMO

Both Colony-stimulating factor 1 receptor (CSF1R) and triggering receptor expressed on myeloid cells-2 (TREM2) are trans-membrane receptors and are expressed in the brain primarily by microglia. Mutations in these two microglia-expressed genes associated with neurodegenerative disease have recently been grouped under the term "microgliopathy". Several literatures have indicated that CSF1R and TREM2 encounters a stepwise shedding and TREM2 variants impair or accelerate the processing. However, whether CSF1R variant affects the shedding of CSF1R remains elusive. Here, plasmids containing human CSF1R or TREM2 were transiently transfected into the human embryonic kidney (HEK) 293T cells. Using Western Blot and/or ELISA assay, we demonstrated that, similar to those of TREM2, an N-terminal fragment (NTF) shedding of CSF1R ectodomain and a subsequent C-terminal fragment (CTF) of CSF1R intra-membrane were generated by a disintegrin and metalloprotease (ADAM) family member and by γ-secretase, respectively. And the shedding was inhibited by treatment with Batimastat, an ADAM inhibitor, or DAPT or compound E, a γ-secretase inhibitor. Importantly, we show that the cleaved fragments, both extracellular domain and intracellular domain of a common disease associated I794T variant, were decreased significantly. Together, our studies demonstrate a stepwise approach of human CSF1R cleavage and contribute to understand the pathogenicity of CSF1R I794T variant in adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP). These studies also suggest that the cleaved ectodomain fragment released from CSF1R may be proposed as a diagnostic biomarker for ALSP.


Assuntos
Secretases da Proteína Precursora do Amiloide/metabolismo , Leucoencefalopatias/patologia , Glicoproteínas de Membrana/metabolismo , Proteínas Mutantes/metabolismo , Mutação , Proteólise , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/metabolismo , Receptores Imunológicos/metabolismo , Secretases da Proteína Precursora do Amiloide/genética , Células HEK293 , Humanos , Leucoencefalopatias/genética , Leucoencefalopatias/metabolismo , Glicoproteínas de Membrana/genética , Proteínas Mutantes/genética , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/genética , Receptores Imunológicos/genética
8.
Cell Death Dis ; 12(2): 166, 2021 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-33558485

RESUMO

A leading cause of preterm birth is the exposure to systemic inflammation (maternal/fetal infection), which leads to neuroinflammation and white matter injury (WMI). A wide range of cytokines and chemokines are expressed and upregulated in oligodendrocytes (OLs) in response to inflammation and numerous reports show that OLs express several receptors for immune related molecules, which enable them to sense inflammation and to react. However, the role of OL immune response in WMI is unclear. Here, we focus our study on toll-like receptor-3 (TLR3) that is activated by double-strand RNA (dsRNA) and promotes neuroinflammation. Despite its importance, its expression and role in OLs remain unclear. We used an in vivo mouse model, which mimics inflammation-mediated WMI of preterm born infants consisting of intraperitoneal injection of IL-1ß from P1 to P5. In the IL-1ß-treated animals, we observed the upregulation of Tlr3, IL-1ß, IFN-ß, Ccl2, and Cxcl10 in both PDGFRα+ and O4+ sorted cells. This upregulation was higher in O4+ immature OLs (immOLs) as compared to PDGFRα+ OL precursor cells (OPCs), suggesting a different sensitivity to neuroinflammation. These observations were confirmed in OL primary cultures: cells treated with TLR3 agonist Poly(I:C) during differentiation showed a stronger upregulation of Ccl2 and Cxcl10 compared to cells treated during proliferation and led to decreased expression of myelin genes. Finally, OLs were able to modulate microglia phenotype and function depending on their maturation state as assessed by qPCR using validated markers for immunomodulatory, proinflammatory, and anti-inflammatory phenotypes and by phagocytosis and morphological analysis. These results show that during inflammation the response of OLs can play an autonomous role in blocking their own differentiation: in addition, the immune activation of OLs may play an important role in shaping the response of microglia during inflammation.


Assuntos
Diferenciação Celular , Proliferação de Células , Encefalite/metabolismo , Leucoencefalopatias/metabolismo , Oligodendroglia/metabolismo , Receptor 3 Toll-Like/metabolismo , Substância Branca/metabolismo , Animais , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Citocinas/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Encefalite/genética , Encefalite/imunologia , Encefalite/patologia , Feminino , Mediadores da Inflamação/metabolismo , Leucoencefalopatias/genética , Leucoencefalopatias/imunologia , Leucoencefalopatias/patologia , Masculino , Camundongos , Microglia/imunologia , Microglia/metabolismo , Microglia/patologia , Oligodendroglia/efeitos dos fármacos , Oligodendroglia/imunologia , Oligodendroglia/patologia , Poli I-C/farmacologia , Gravidez , Nascimento Prematuro , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/genética , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/metabolismo , Transdução de Sinais , Receptor 3 Toll-Like/agonistas , Substância Branca/efeitos dos fármacos , Substância Branca/imunologia , Substância Branca/patologia
9.
Hum Mol Genet ; 30(5): 331-342, 2021 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-33517449

RESUMO

Leukodystrophy with vanishing white matter (VWM), also called Childhood Ataxia with Central Nervous System Hypomyelination, is caused by mutations in the subunits of the eukaryotic translation initiation factor, EIF2B1, EIF2B2, EIF2B3, EIF2B4 or EIF2B5. However, little is known regarding the underlying pathogenetic mechanisms, and there is no curative treatment for VWM. In this study, we established the first EIF2B3 animal model for VWM disease in vertebrates by CRISPR mutagenesis of the highly conserved zebrafish ortholog eif2b3. Using CRISPR, we generated two mutant alleles in zebrafish eif2b3, 10- and 16-bp deletions, respectively. The eif2b3 mutants showed defects in myelin development and glial cell differentiation, and increased expression of genes in the induced stress response pathway. Interestingly, we also found ectopic angiogenesis and increased VEGF expression. Ectopic angiogenesis in the eif2b3 mutants was reduced by the administration of VEGF receptor inhibitor SU5416. Using the eif2b3 mutant zebrafish model together with in silico protein modeling analysis, we demonstrated the pathogenicity of 18 reported mutations in EIF2B3, as well as of a novel variant identified in a 19-month-old female patient: c.503 T > C (p.Leu168Pro). In summary, our zebrafish mutant model of eif2b3 provides novel insights into VWM pathogenesis and offers rapid functional analysis of human EIF2B3 gene variants.


Assuntos
Fator de Iniciação 2B em Eucariotos/genética , Regulação da Expressão Gênica no Desenvolvimento , Leucoencefalopatias/genética , Bainha de Mielina/genética , Neovascularização Fisiológica , Peixe-Zebra/genética , Peixe-Zebra/metabolismo , Alelos , Animais , Diferenciação Celular , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Modelos Animais de Doenças , Fator de Iniciação 2B em Eucariotos/química , Feminino , Técnicas de Inativação de Genes , Humanos , Lactente , Leucoencefalopatias/metabolismo , Modelos Moleculares , Bainha de Mielina/metabolismo , Neovascularização Fisiológica/genética , Conformação Proteica , Deleção de Sequência , Estresse Fisiológico , Fator A de Crescimento do Endotélio Vascular/metabolismo
10.
J Exp Med ; 218(1)2021 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-32991666

RESUMO

Neonatal hypoxic-ischemic encephalopathy (HIE) with the pathological characteristic of white matter injury often leads to lifelong cognitive and neurobehavioral dysfunction, but relevant therapies to promote remyelination are still unavailable. We found that histamine H2 receptor (H2R) negatively regulated the oligodendrocyte differentiation rate without affecting the oligodendrocytes at the oligodendrocyte precursor cell stage or mature stage following oxygen-glucose deprivation in vitro. Notably, selective deletion of the H2R gene (Hrh2) in differentiating oligodendrocytes (Hrh2fl/fl;CNPase-Cre) improved their differentiation, remyelination, and functional recovery following neonatal hypoxia-ischemia in mice. The regulation of oligodendrocyte differentiation by H2R is mediated by binding with Axin2, which leads to up-regulation of the Wnt/ß-catenin signaling pathway. Furthermore, H2R antagonists also promoted oligodendrocyte differentiation and remyelination and the recovery of cognition and motor functions following neonatal hypoxia-ischemia. Thus, histamine H2R in oligodendrocytes could serve as a novel and effective therapeutic target for the retard of oligodendrocyte differentiation and remyelination following neonatal hypoxia-ischemia. The H2R antagonists may have potential therapeutic value for neonatal HIE.


Assuntos
Isquemia Encefálica/metabolismo , Diferenciação Celular , Leucoencefalopatias/metabolismo , Oligodendroglia/metabolismo , Receptores Histamínicos H2/metabolismo , Substância Branca/metabolismo , Animais , Isquemia Encefálica/patologia , Antagonistas dos Receptores H2 da Histamina/farmacologia , Leucoencefalopatias/patologia , Camundongos , Oligodendroglia/patologia , Substância Branca/patologia , Via de Sinalização Wnt/efeitos dos fármacos
11.
J Biol Chem ; 296: 100207, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33334879

RESUMO

Eukaryotic initiation factor 2B (eIF2B) serves as a vital control point within protein synthesis and regulates translation initiation in response to cellular stress. Mutations within eIF2B result in the fatal disease, leukoencephalopathy with vanishing white matter (VWM). Previous biochemical studies on VWM mutations have illustrated that changes in the activity of eIF2B poorly correlate with disease severity. This suggests that there may be additional characteristics of eIF2B contributing to VWM pathogenesis. Here, we investigated whether the localization of eIF2B to eIF2B bodies was integral for function and whether this localization could provide insight into the pathogenesis of VWM. We demonstrate that the regulatory subunit, eIF2Bα, is required for the assembly of eIF2B bodies in yeast and that loss of eIF2B bodies correlates with an inability of cells to regulate eIF2B activity. Mutational analysis of eIF2Bα showed that missense mutations that disrupt the regulation of eIF2B similarly disrupt the assembly of eIF2B bodies. In contrast, when eIF2Bα mutations that impact the catalytic activity of eIF2B were analyzed, eIF2B bodies were absent and instead eIF2B localized to small foci, termed microfoci. Fluorescence recovery after photobleaching analysis highlighted that within these microfoci, eIF2 shuttles more slowly indicating that formation of eIF2B bodies correlates with full eIF2B activity. When eIF2Bα VWM mutations were analyzed, a diverse impact on localization was observed, which did not seem to correlate with eIF2B activity. These findings provide key insights into how the eIF2B body assembles and suggest that the body is a fundamental part of the translational regulation via eIF2α phosphorylation.


Assuntos
Fator de Iniciação 2 em Eucariotos/genética , Leucoencefalopatias/patologia , Mutação de Sentido Incorreto , Mutação , Processamento de Proteína Pós-Traducional , Saccharomyces cerevisiae/metabolismo , Análise Mutacional de DNA/métodos , Fator de Iniciação 2 em Eucariotos/metabolismo , Humanos , Leucoencefalopatias/genética , Leucoencefalopatias/metabolismo , Mutagênese Sítio-Dirigida/métodos , Biossíntese de Proteínas , Saccharomyces cerevisiae/genética
12.
Mol Genet Metab ; 132(1): 11-18, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33334682

RESUMO

Even with early and continuous treatment, individuals with phenylketonuria (PKU) may exhibit abnormalities of cortical white matter (WM). The present study utilizes a new analysis approach called Automated Fiber-Tract Quantification (AFQ) to advance our understanding of the tract-specific patterns of change in WM abnormalities in individuals with early-treated PKU (ETPKU). Diffusion Tensor Imaging (DTI) data from a sample of 22 individuals with ETPKU and a demographically-matched sample of 21 healthy individuals without PKU was analyzed using AFQ. In addition, a subsample of 8 individuals with ETPKU was reevaluated six months later after demonstrating a significant reduction in blood phe levels following initiation of sapropterin treatment. Within-tract AFQ analyses revealed significant location-by-group interactions for several WM tracts throughout the brain. In most cases, ETPKU-related disruptions in mean diffusivity (MD) were more apparent in posterior (as compared to anterior) aspects of a given tract. Reduction in blood phe levels with the aforementioned ETPKU subsample was associated with a similar pattern of improvement (posterior-to-anterior) within most tracts. Taken together, these findings suggest that there is a systematic pattern of change in WM abnormalities in individuals with ETPKU in a posterior-to-anterior manner along individual WM tracts.


Assuntos
Encéfalo/metabolismo , Leucoencefalopatias/diagnóstico , Fenilcetonúrias/diagnóstico , Substância Branca/metabolismo , Adolescente , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Criança , Cognição/fisiologia , Imagem de Tensor de Difusão , Feminino , Humanos , Leucoencefalopatias/diagnóstico por imagem , Leucoencefalopatias/metabolismo , Masculino , Fenilcetonúrias/diagnóstico por imagem , Fenilcetonúrias/metabolismo , Fenilcetonúrias/patologia , Substância Branca/anormalidades , Substância Branca/diagnóstico por imagem , Substância Branca/patologia , Adulto Jovem
13.
Elife ; 92020 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-33300869

RESUMO

Vanishing white matter disease (VWM) is a severe leukodystrophy of the central nervous system caused by mutations in subunits of the eukaryotic initiation factor 2B complex (eIF2B). Current models only partially recapitulate key disease features, and pathophysiology is poorly understood. Through development and validation of zebrafish (Danio rerio) models of VWM, we demonstrate that zebrafish eif2b mutants phenocopy VWM, including impaired somatic growth, early lethality, effects on myelination, loss of oligodendrocyte precursor cells, increased apoptosis in the CNS, and impaired motor swimming behavior. Expression of human EIF2B2 in the zebrafish eif2b2 mutant rescues lethality and CNS apoptosis, demonstrating conservation of function between zebrafish and human. In the mutants, intron 12 retention leads to expression of a truncated eif2b5 transcript. Expression of the truncated eif2b5 in wild-type larva impairs motor behavior and activates the ISR, suggesting that a feed-forward mechanism in VWM is a significant component of disease pathophysiology.


Assuntos
Modelos Animais de Doenças , Fator de Iniciação 2B em Eucariotos/genética , Fator de Iniciação 2B em Eucariotos/metabolismo , Leucoencefalopatias/genética , Leucoencefalopatias/metabolismo , Animais , Humanos , Leucoencefalopatias/fisiopatologia , Mutação , Estresse Fisiológico/fisiologia , Peixe-Zebra
14.
Genes (Basel) ; 11(9)2020 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-32887222

RESUMO

The EARS2 nuclear gene encodes mitochondrial glutamyl-tRNA synthetase, a member of the class I family of aminoacyl-tRNA synthetases (aaRSs) that plays a crucial role in mitochondrial protein biosynthesis by catalyzing the charging of glutamate to mitochondrial tRNA(Glu). Pathogenic EARS2 variants have been associated with a rare mitochondrial disorder known as leukoencephalopathy with thalamus and brainstem involvement and high lactate (LTBL). The targeted sequencing of 150 nuclear genes encoding respiratory chain complex subunits and proteins implicated in the oxidative phosphorylation (OXPHOS) function was performed. The oxygen consumption rate (OCR), and the extracellular acidification rate (ECAR), were measured. The enzymatic activities of Complexes I-V were analyzed spectrophotometrically. We describe a patient carrying two heterozygous EARS2 variants, c.376C>T (p.Gln126*) and c.670G>A (p.Gly224Ser), with infantile-onset disease and a severe clinical presentation. We demonstrate a clear defect in mitochondrial function in the patient's fibroblasts, suggesting the molecular mechanism underlying the pathogenicity of these EARS2 variants. Experimental validation using patient-derived fibroblasts allowed an accurate characterization of the disease-causing variants, and by comparing our patient's clinical presentation with that of previously reported cases, new clinical and radiological features of LTBL were identified, expanding the clinical spectrum of this disease.


Assuntos
Variação Genética/genética , Glutamato-tRNA Ligase/genética , Ácido Láctico/metabolismo , Leucoencefalopatias/genética , Adulto , Aminoacil-tRNA Sintetases/genética , Tronco Encefálico/metabolismo , Células Cultivadas , Feminino , Fibroblastos/metabolismo , Humanos , Leucoencefalopatias/metabolismo , Mitocôndrias/genética , Mitocôndrias/metabolismo , Fosforilação Oxidativa , Consumo de Oxigênio/genética , Fenótipo , RNA de Transferência/genética , Tálamo/metabolismo , Adulto Jovem
15.
J Thorac Cardiovasc Surg ; 160(2): e55-e66, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32689704

RESUMO

OBJECTIVES: This study aims to evaluate the protective effects of progesterone on white matter injury and brain immaturity in neonatal rats with chronic hypoxia. METHODS: Three-day old Sprague-Dawley rats were randomly divided into 3 groups: (1) control (n = 48), rats were exposed to normoxia (fraction of inspired oxygen: 21% ± 0%); (2) chronic hypoxia (n = 48), rats were exposed to hypoxia (fraction of inspired oxygen: 10.5% ± 1.0%); and (3) progesterone (n = 48), rats were exposed to hypoxia and administrated with progesterone (8 mg/kg/d). Hematoxylin-eosin staining, immunohistochemistry, real-time quantitative polymerase chain reaction, and Western blot analyses were compared on postnatal day 14 in different groups. Motor skill and coordination abilities of rats were assessed via rotation experiments. RESULTS: Increased brain weights (P < .05), narrowed ventricular sizes (P < .01), and rotarod experiment scores (P < .01) were better in the progesterone group than in the chronic hypoxia group. The number of mature oligodendrocytes and myelin basic protein expression increased in the progesterone group compared with the chronic hypoxia group (P < .01). The polarization of M1 microglia cells in the corpus callosum of chronic hypoxia-induced hypomyelination rats was significantly increased, whereas there were fewer M2 microglia cells. Conversely, progesterone therapy had an opposite effect and caused an increase in M2 microglia polarization versus a reduction in M1 microglia cells. CONCLUSIONS: Progesterone could prevent white matter injury and improve brain maturation in a neonatal hypoxic rat model; this may be associated with inducing a switch from M1 to M2 in microglia.


Assuntos
Encéfalo/efeitos dos fármacos , Hipóxia/tratamento farmacológico , Leucoencefalopatias/prevenção & controle , Fármacos Neuroprotetores/farmacologia , Progesterona/farmacologia , Substância Branca/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Comportamento Animal/efeitos dos fármacos , Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , Plasticidade Celular/efeitos dos fármacos , Doença Crônica , Modelos Animais de Doenças , Feminino , Hipóxia/metabolismo , Hipóxia/patologia , Hipóxia/fisiopatologia , Leucoencefalopatias/metabolismo , Leucoencefalopatias/patologia , Leucoencefalopatias/fisiopatologia , Masculino , Microglia/efeitos dos fármacos , Microglia/metabolismo , Microglia/patologia , Atividade Motora/efeitos dos fármacos , Proteína Básica da Mielina/metabolismo , Oligodendroglia/efeitos dos fármacos , Oligodendroglia/metabolismo , Oligodendroglia/patologia , Ratos Sprague-Dawley , Substância Branca/metabolismo , Substância Branca/patologia , Substância Branca/fisiopatologia
16.
Clin Nucl Med ; 45(10): e439-e440, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32657880

RESUMO

A 69-year-old woman presented with cognitive impairment related to attentive, executive, and mnemonic functions; progressive worsening of walking, speaking, writing, and reading ability; and double sphincter incontinence. Leukoencephalopathy, cystic lesions, and calcifications, suspected for Labrune syndrome, were observed at MRI and CT brain images. Generalized wave abnormalities were also visible at electroencephalogram. Functional brain imaging performed with F-FDG PET/CT demonstrated a decreased glucose metabolism in impaired brain regions, in accordance with MRI findings. Genetic testing confirmed a mutation of SNORD118.


Assuntos
Calcinose/diagnóstico por imagem , Cistos do Sistema Nervoso Central/diagnóstico por imagem , Fluordesoxiglucose F18 , Leucoencefalopatias/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Idoso , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Calcinose/genética , Calcinose/metabolismo , Cistos do Sistema Nervoso Central/genética , Cistos do Sistema Nervoso Central/metabolismo , Glucose/metabolismo , Humanos , Leucoencefalopatias/genética , Leucoencefalopatias/metabolismo , Imageamento por Ressonância Magnética , Masculino , Mutação , RNA Nucleolar Pequeno/genética
17.
Stroke ; 51(6): 1750-1757, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32397933

RESUMO

Background and Purpose- Distribution patterns of iron deposition in deep gray matter and their association with clinical characteristics in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) remain unclear. We aimed to evaluate iron deposition in deep gray matter in patients with CADASIL using 7.0-T susceptibility-weighted imaging and mapping and to explore its correlations with clinical characteristics. Methods- Thirty-nine patients with CADASIL, confirmed via genetic analysis or skin biopsy, were enrolled. We examined patients using the Mini-Mental State Examination, modified Rankin Scale, and brain 7.0-T magnetic resonance imaging and obtained magnetic resonance imaging lesion loads, small vessel disease scores, and susceptibility mapping. The following regions of interest were selected: caudate nucleus, putamen, globus pallidus, thalamus, substantia nigra, and red nucleus. The quantitative differences in the susceptibility of deep gray matter between the CADASIL and control groups and the correlations between deep gray matter susceptibility and clinical characteristics were identified. Results- Compared with the control group, the CADASIL group showed significantly increased susceptibility of caudate nucleus, putamen, thalamus, substantia nigra, and red nucleus. The susceptibility of deep gray matter in basal ganglia region, including caudate nucleus, putamen, and thalamus, significantly increased with age or disease duration and positively correlated with small vessel disease scores in patients with CADASIL. Moreover, the susceptibility of thalamus positively correlated with modified Rankin Scale scores after adjusting for age and disease duration and that of putamen negatively correlated with Mini-Mental State Examination scores in patients with CADASIL after adjusting for age. Conclusions- Our findings indicate an association between abnormal iron deposition in deep gray matter of patients with CADASIL and their clinical characteristics. Therefore, excess iron deposition in deep gray matter, as indicated by 7.0-T susceptibility-weighted imaging and mapping, might not only be a novel magnetic resonance imaging feature but also a potential biomarker for CADASIL severity.


Assuntos
Alopecia/diagnóstico por imagem , Alopecia/metabolismo , Infarto Cerebral/diagnóstico por imagem , Infarto Cerebral/metabolismo , Substância Cinzenta , Ferro/metabolismo , Leucoencefalopatias/diagnóstico por imagem , Leucoencefalopatias/metabolismo , Imageamento por Ressonância Magnética , Doenças da Coluna Vertebral/diagnóstico por imagem , Doenças da Coluna Vertebral/metabolismo , Adulto , Alopecia/genética , Infarto Cerebral/genética , Feminino , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/metabolismo , Humanos , Leucoencefalopatias/genética , Masculino , Pessoa de Meia-Idade , Doenças da Coluna Vertebral/genética
18.
Acta Neuropathol Commun ; 8(1): 72, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32430064

RESUMO

Microglia are resident macrophages of the central nervous system, and their unique molecular signature is dependent upon CSF-1 signaling. Previous studies have demonstrated the importance of CSF-1R in survival and development of microglia in animal models, but the findings are of uncertain relevance to understanding the influence of CSF-1R on microglia in humans. Hereditary diffuse leukoencephalopathy with spheroids (HDLS) [also known as adult onset leukoencephalopathy with spheroids and pigmented glia (ALSP)] is a neurodegenerative disorder primarily affecting cerebral white matter, most often caused by mutations of CSF1R. Therefore, we hypothesized that the molecular profile of microglia may be affected in HDLS. Semi-quantitative immunohistochemistry and quantitative transcriptomic profiling revealed reduced expression of IBA-1 and P2RY12 in both white and gray matter microglia of HDLS. In contrast, there was increased expression of CD68 and CD163 in microglia in affected white matter. In addition, expression of selective and specific microglial markers, including P2RY12, CX3CR1 and CSF-1R, were reduced in affected white matter. These results suggest that microglia in white matter in HDLS lose their homeostatic phenotype. Supported by gene ontology analysis, it is likely that an inflammatory phenotype is a key pathogenic feature of microglia in vulnerable brain regions of HDLS. Our findings suggest a potential mechanism of disease pathogenesis by linking aberrant CSF-1 signaling to altered microglial phenotype. They also support the idea that HDLS may be a primary microgliopathy. We observed increased expression of CSF-2 in gray matter compared to affected white matter, which may contribute to selective vulnerability of white matter in HDLS. Our findings suggest that methods that restore the homeostatic phenotype of microglia might be considered treatment approaches in HDLS.


Assuntos
Encéfalo/metabolismo , Encéfalo/patologia , Leucoencefalopatias/metabolismo , Leucoencefalopatias/patologia , Microglia/metabolismo , Microglia/patologia , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/metabolismo , Idoso , Proteínas de Ligação ao Cálcio/metabolismo , Feminino , Substância Cinzenta/metabolismo , Substância Cinzenta/patologia , Homeostase , Humanos , Masculino , Proteínas dos Microfilamentos/metabolismo , Pessoa de Meia-Idade , Fenótipo , Receptores Purinérgicos P2Y12/metabolismo , Transdução de Sinais , Transcriptoma , Substância Branca/metabolismo , Substância Branca/patologia
19.
Biol Open ; 9(5)2020 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-32295832

RESUMO

Human infantile-onset RNASET2-deficient cystic leukoencephalopathy is a Mendelian mimic of in utero cytomegalovirus brain infection with prenatally developing inflammatory brain lesions. We used an RNASET2-deficient zebrafish model to elucidate the underlying disease mechanisms. Mutant and wild-type zebrafish larvae brain development between 2 and 5 days post fertilization (dpf) was examined by confocal live imaging in fluorescent reporter lines of the major types of brain cells. In contrast to wild-type brains, RNASET2-deficient larvae displayed increased numbers of microglia with altered morphology, often containing inclusions of neurons. Furthermore, lysosomes within distinct populations of the myeloid cell lineage including microglia showed increased lysosomal staining. Neurons and oligodendrocyte precursor cells remained unaffected. This study provides a first look into the prenatal onset pathomechanisms of human RNASET2-deficient leukoencephalopathy, linking this inborn lysosomal disease to the innate immune system and other immune-related childhood encephalopathies like Aicardi-Goutières syndrome (AGS).


Assuntos
Estudos de Associação Genética , Predisposição Genética para Doença , Leucoencefalopatias/diagnóstico , Leucoencefalopatias/genética , Leucoencefalopatias/metabolismo , Microglia/metabolismo , Fenótipo , Ribonucleases/deficiência , Proteínas Supressoras de Tumor/deficiência , Animais , Apoptose , Suscetibilidade a Doenças , Estudos de Associação Genética/métodos , Humanos , Larva , Neurônios/metabolismo , Organogênese/genética , Rombencéfalo/anormalidades , Rombencéfalo/embriologia , Rombencéfalo/metabolismo , Peixe-Zebra
20.
Glia ; 68(7): 1531-1545, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32212285

RESUMO

The contribution of microglia in neurological disorders is emerging as a leading disease driver rather than a consequence of pathology. RNAseT2-deficient leukoencephalopathy is a severe childhood white matter disorder affecting patients in their first year of life and mimicking a cytomegalovirus brain infection. The early onset and resemblance of the symptoms to a viral infection suggest an inflammatory and embryonic origin of the pathology. There are no treatments available for this disease as our understanding of the cellular drivers of the pathology are still unknown. In this study, using a zebrafish mutant for the orthologous rnaset2 gene, we have identified an inflammatory signature in early development and an antiviral immune response in mature adult brains. Using the optical transparency and the ex utero development of the zebrafish larvae we studied immune cell behavior during brain development and identified abnormal microglia as an early marker of pathology. Live imaging and electron microscopy identified that mutant microglia displayed an engorged morphology and were filled with undigested apoptotic cells and undigested substrate. Using microglia-specific depletion and rescue experiments, we identified microglia as drivers of this embryonic phenotype and potential key cellular player in the pathology of RNAseT2-deficient leukoencephalopathy. Our zebrafish model also presented with reduced survival and locomotor defects, therefore recapitulating many aspects of the human disease. Our study therefore placed our rnaset2 mutant at the forefront of leukodystrophy preclinical models and highlighted tissue-specific approaches as future therapeutic avenues.


Assuntos
Apoptose/fisiologia , Encéfalo/metabolismo , Leucoencefalopatias/patologia , Microglia/metabolismo , Animais , Leucoencefalopatias/metabolismo , Mutação/genética , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Fenótipo , Peixe-Zebra , Proteínas de Peixe-Zebra/metabolismo
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