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1.
Alsalem A  Shaheen R  Alkuraya FS 《Gene》2012,496(2):141-143
Vanishing white matter disease (VWMD) is an autosomal recessive disorder characterized by progressive degeneration of the white matter. While variable clinical presentation is well documented, there are no reports of adrenal insufficiency. We describe a young Saudi girl with VWMD whose atypical phenotype suggested adrenoleukodystrophy. This complicated the diagnostic workup until homozygosity scan revealed a novel mutation in EIF2B2.This report widens the clinical spectrum of VWMD and raises the possibility of an allele-specific association with adrenal insufficiency.  相似文献   

2.
Leukoencephalopathy with vanishing white matter (VWM) is one of the most prevalent inherited childhood white matter disorders, which caused by mutations in each of the five subunits of eukaryotic translation initiation factor 2B (EIF2B1-5). In our study, 34 out of the 36 clinically diagnosed children (94%) were identified to have EIF2B1-5 mutations by sequencing. 15 novel mutations were identified. CNVs were not detected in patients with only one mutant allele and mutation-negative determined by gene sequencing. There is a significantly higher incidence of patients with EIF2B3 mutations compared with Caucasian patients (32% vs. 4%). c.1037T>C (p.Ile346Thr) in EIF2B3 was confirmed to be a founder mutation in Chinese, which probably one of the causes of the genotypic differences between ethnicities. Our average 4.4 years-follow-up on infantile, early childhood and juvenile VWM children suggested a rapid deterioration in motor function. Episodic aggravation was presented in 90% of infantile cases and 71.4% of childhood cases. 10 patients died during the follow-up. The Kaplan-Meier curve showed that the median survival time is 8.83 ± 1.51 years. This is the largest sample of children in a VWM follow-up study, which is helpful for a more depth understanding about the natural course.  相似文献   

3.
Vanishing white matter disease (VWM) is a heritable leukodystrophy linked to mutations in translation initiation factor 2B (eIF2B). Although the clinical course of this disease has been relatively well described, the cellular consequences of EIF2B mutations on neural cells are unknown. Here we have established cell cultures from the brain of an individual with VWM carrying mutations in subunit 5 of eIF2B (encoded by EIF2B5). Despite the extensive demyelination apparent in this VWM patient, normal-appearing oligodendrocytes were readily generated in vitro. In contrast, few GFAP-expressing (GFAP+) astrocytes were present in primary cultures, induction of astrocytes was severely compromised, and the few astrocytes generated showed abnormal morphologies and antigenic phenotypes. Lesions in vivo also lacked GFAP+ astrocytes. RNAi targeting of EIF2B5 severely compromised the induction of GFAP+ cells from normal human glial progenitors. This raises the possibility that a deficiency in astrocyte function may contribute to the loss of white matter in VWM leukodystrophy.  相似文献   

4.
目的 探讨白质消融性白质脑病中胶质细胞选择性受累而神经元受累轻微的原因。方法EIF2B5-RNAi表达载体转染至人星形胶质细胞和人神经元,检测基础状态下及内质网应激(endoplasmic reticulum stress,ERS)后细胞凋亡和活力,检测参与ERS调控的已知和未知miRNA,筛选EIF2B5-RNAi人星形胶质细胞在ERS后miRNA变化。结果EIF2B5-RNAi人神经元相比,星形胶质细胞自发凋亡及细胞活力下降。较之神经元,更多miRNA参与星形胶质细胞ERS刺激后的调控,EIF2B5-RNAi组参与调控的miRNA数目显著减少。聚类分析发现,5条已知miRNA是通路连接的关键组分。结论 人星形胶质细胞在ERS后可能更加依赖众多促细胞增殖分化的miRNA修复,而EIF2B5-RNAi人星形胶质细胞存在自发凋亡,ERS后严重减少的miRNA可能导致细胞无法存活。  相似文献   

5.

Background  

Alexander disease (ALX) is a rare neurological disorder characterized by white matter degeneration and cytoplasmic inclusions in astrocytes called Rosenthal fibers, labeled by antibodies against glial fibrillary acidic protein (GFAP). Three subtypes are distinguished according to age at onset: infantile (under age 2), juvenile (age 2 to 12) and adult (over age 12). Following the identification of heterozygous mutations in GFAP that cause this disease, cases of adult-onset ALX have been increasingly reported.  相似文献   

6.
The eukaryotic translation initiation factor eIF2B promotes mRNA translation as a guanine nucleotide exchange factor (GEF) for translation initiation factor 2 (eIF2). Endoplasmic reticulum (ER) stress-mediated activation of the kinase PERK and the resultant phosphorylation of eIF2’s alpha subunit (eIF2α) attenuates eIF2B GEF activity thereby inducing an integrated stress response (ISR) that defends against protein misfolding in the ER. Mutations in all five subunits of human eIF2B cause an inherited leukoencephalopathy with vanishing white matter (VWM), but the role of the ISR in its pathogenesis remains unclear. Using CRISPR-Cas9 genome editing we introduced the most severe known VWM mutation, EIF2B4A391D, into CHO cells. Compared to isogenic wildtype cells, GEF activity of cells with the VWM mutation was impaired and the mutant cells experienced modest enhancement of the ISR. However, despite their enhanced ISR, imposed by the intrinsic defect in eIF2B, disrupting the inhibitory effect of phosphorylated eIF2α on GEF by a contravening EIF2S1/eIF2αS51A mutation that functions upstream of eIF2B, selectively enfeebled both EIF2B4A391D and the related severe VWM EIF2B4R483W cells. The basis for paradoxical dependence of cells with the VWM mutations on an intact eIF2α genotype remains unclear, as both translation rates and survival from stressors that normally activate the ISR were not reproducibly affected by the VWM mutations. Nonetheless, our findings support an additional layer of complexity in the development of VWM, beyond a hyperactive ISR.  相似文献   

7.
Several neurodegenerative disorders are known to predominantly affect the white matter of the brain including vanishing white matter disease (VWMD), an autosomal recessive disorder characterized by leukodystrophy of varying severity in addition to variable systemic involvement. We report a consanguineous Arab family with three affected children, all of whom presented with severe neonatal epilepsy and profound neurodegenerative disease characterized by marked leukodystrophy with white matter cavitation mimicking VWMD. We combined autozygome and exome analysis to identify a novel variant in the gene encoding a member of the eIF2B-related family of proteins (MRI1). This is a poorly understood family of proteins of unclear function. Our results represent the first link between a variant in a member of this family and a human disease, and suggest that it converges with the highly homologous eIF2B, known to be mutated in VWMD, on the molecular pathogenesis of neurodegeneration.  相似文献   

8.

Background

Mutations in any of the five subunits of eukaryotic translation initiation factor 2B (eIF2B) can lead to an inherited chronic-progressive fatal brain disease of unknown aetiology termed leucoencephalopathy with vanishing white matter (VWM). VWM is one of the most prevalent childhood white matter disorders, which markedly deteriorates after inflammation or exposure to other stressors. eIF2B is a major housekeeping complex that governs the rate of global protein synthesis under normal and stress conditions. A previous study demonstrated that Eif2b5R132H/R132H mice suffer delayed white matter development and fail to recover from cuprizone-induced demyelination, although eIF2B enzymatic activity in the mutant brain is reduced by merely 20%.

Principal Findings

Poor astrogliosis was observed in Eif2b5R132H/R132H mice brain in response to systemic stress induced by peripheral injections of lipopolysaccharide (LPS). Even with normal rates of protein synthesis under normal conditions, primary astrocytes and microglia isolated from mutant brains fail to adequately synthesise and secrete cytokines in response to LPS treatment despite proper induction of cytokine mRNAs.

Conclusions

The mild reduction in eIF2B activity prevents the appropriate increase in translation rates upon exposure to the inflammatory stressor LPS. The data underscore the importance of fully-functional translation machinery for efficient cerebral inflammatory response upon insults. It highlights the magnitude of proficient translation rates in restoration of brain homeostasis via microglia-astrocyte crosstalk. This study is the first to suggest the involvement of microglia in the pathology of VWM disease. Importantly, it rationalises the deterioration of clinical symptoms upon exposure of VWM patients to physiological stressors and provides possible explanation for their high phenotypic variability.  相似文献   

9.
10.
Excessive activation of immune cells plays a key role in the pathogenesis of systemic lupus erythematosus (SLE). The regulation of immune cells by miRNAs is a research hotspot. In this study, second-generation high-throughput sequencing revealed a reduction in miR-99a-3p expression in patients with SLE; however, the specific mechanism underlying this phenomenon remains unclear. After transfection with an miR-99a-3p agomir, the proliferation of Ball-1 cells decreased and the levels of their apoptosis increased. The opposite effects were observed in cells transfected with the miR-99a-3p antagomir. Luciferase reporter assay indicated that miR-99a-3p directly targeted EIF4EBP1. Rescue experiments confirmed the proposed interaction between miR-99a-3p and EIF4EBP1. In vitro, in vivo and clinical investigations further confirmed that the miR-99a-3p agomir reduced the expression of EIF4EBP1, LC3B and LAMP-2A. In the in vivo experiments, serum levels of anti-nuclear antibodies, double-stranded DNA, IgE, IgM, IL-6, IL-10 and B lymphocyte stimulator were higher in mice from the antagomir group than those in mice from the MRL/lpr group. Furthermore, the protein and mRNA levels of EIF4EBP1, LC3B and LAMP-2A, the intensity of immunohistochemical staining of EIF4EBP1, LC3B and LAMP-2A, the urinary protein levels, and the C3 immunofluorescence deposition increased in mice from the antagomir group. The upregulation of miR-99a-3p expression protected B cells from EIF4EBP1-mediated autophagy, whilst the downregulation of miR-99a-3p expression induced autophagy via the EIF4EBP1-mediated regulation of the autophagy signalling pathway in B cells isolated from individuals with SLE. Based on these results, miR-99a-3p and EIF4EBP1 may be considered potential targets for SLE treatment.  相似文献   

11.
Generation of nitric oxide (NO?) can upstream induce and downstream mediate the kinases that phosphorylate the α subunit of eukaryotic initiation factor 2 (eIF2α), which plays a critical role in regulating gene expression. There are four known eIF2α kinases (EIF2AKs), and NO? affects each one uniquely. Whereas NO? directly activates EIF2AK1 (HRI), it indirectly activates EIF2AK3 (PERK). EIF2AK4 (GCN2) is activated by depletion of l-arginine, which is used by nitric oxide synthase (NOS) during the production of NO?. Finally EIF2AK2 (PKR), which can mediate inducible NOS expression and therefore NO? production, can also be activated by NO?. The production of NO? and activation of EIF2AKs coordinately regulate physiological and pathological events such as innate immune response and cell apoptosis.  相似文献   

12.
Centronuclear myopathy (CNM) is a rare congenital muscle disease characterized by fibers with prominent centralized nuclei in muscle biopsies. The disease is clinically heterogeneous, ranging from severe neonatal hypotonic phenotypes to adult-onset mild muscle weakness, and can have multiple modes of inheritance in association with various genes, including MTM1, DNM2, BIN1 and RYR1. Here we analyzed 18 sporadic patients with clinical and histological diagnosis of CNM and sequenced the DNM2 gene, which codes for the dynamin 2 protein. We found DNM2 missense mutations in two patients, both in exon 8, one known (p.E368K) and one novel (p.F372C), which is found in a position of presumed pathogenicity and appeared de novo. The patients had similar phenotypes characterized by neonatal signs followed by improvement and late childhood reemergence of slowly progressive generalized muscle weakness, elongated face with ptosis and ophthalmoparesis, and histology showing fibers with radiating sarcoplasmic strands (RSS). These patients were the only ones in the series to present this histological marker, which together with previous reports in the literature suggest that, when RSS are present, direct sequencing of DNM2 mutation hot spot regions should be the first step in the molecular diagnosis of CNM, even in sporadic cases.  相似文献   

13.

Background

Alzheimer’s disease (AD) is generally considered to be characterized by pathology in gray matter of the brain, but convergent evidence suggests that white matter degradation also plays a vital role in its pathogenesis. The evolution of white matter deterioration and its relationship with gray matter atrophy remains elusive in amnestic mild cognitive impairment (aMCI), a prodromal stage of AD.

Methods

We studied 155 cognitively normal (CN) and 27 ‘late’ aMCI individuals with stable diagnosis over 2 years, and 39 ‘early’ aMCI individuals who had converted from CN to aMCI at 2-year follow up. Diffusion tensor imaging (DTI) tractography was used to reconstruct six white matter tracts three limbic tracts critical for episodic memory function - the fornix, the parahippocampal cingulum, and the uncinate fasciculus; two cortico-cortical association fiber tracts - superior longitudinal fasciculus and inferior longitudinal fasciculus; and one projection fiber tract - corticospinal tract. Microstructural integrity as measured by fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AxD) was assessed for these tracts.

Results

Compared with CN, late aMCI had lower white matter integrity in the fornix, the parahippocampal cingulum, and the uncinate fasciculus, while early aMCI showed white matter damage in the fornix. In addition, fornical measures were correlated with hippocampal atrophy in late aMCI, whereas abnormality of the fornix in early aMCI occurred in the absence of hippocampal atrophy and did not correlate with hippocampal volumes.

Conclusions

Limbic white matter tracts are preferentially affected in the early stages of cognitive dysfunction. Microstructural degradation of the fornix preceding hippocampal atrophy may serve as a novel imaging marker for aMCI at an early stage.  相似文献   

14.
Congenital muscular dystrophies (CMD) are a group of heterogeneous inherited autosomal recessive disorders characterized by muscular weakness, hypotonia and contractures. The Merosin Negative CMD (MNCMD) is considered to be the most severe form and is usually associated with white matter abnormalities as seen with brain imaging. Merosin is also expressed in the nervous system and its deficiency could affect its development. This article describes the clinical picture, muscle biopsy findings and neuroimaging abnormalities of eight Egyptian Pediatric patients with the clinical presentation of merosin negative congenital muscular dystrophy. The leading clinical presentation in almost all patients was severe hypotonia, muscular weakness and failure to achieve motor developmental milestones, only Case 2 walked at 2 years of age. Mentality was normal in most patients with exception of Case 2 in whom scholastic achievement was poor and was associated with behavior abnormality. Serum Creatine kinase ranged from moderate to severe elevation, 536–3563 U/L, Electromyography demonstrated a myopathic pattern in all patients. Brain MRI showed extensive demyelination of the cerebral white matter in 6/8 patients with extension to cerebellar demyelination in Case 5. 5/8 patients underwent muscle biopsy for which immunofluorescence staining for merosin demonstrated complete deficiency of laminin α2 in Case 5 & partial deficiency of laminin α2 in Case 2.This report demonstrates the utility of Immunofluorescence staining as a guide to confirm the diagnosis of MDCMD especially when molecular diagnosis is not available.  相似文献   

15.
Ovarian failure (OF) at age <40 years occurs in approximately 1% of all women. Other than karyotype abnormalities, very few genes are known to be associated with this ovarian dysfunction. We studied eight patients who presented with premature OF and white-matter abnormalities on magnetic resonance imaging. Neurological signs may be absent or present after OF. In seven patients, we report for the first time mutations in three of the five EIF2B genes (EIF2B2, -4, and -5) that were recently shown to cause childhood ataxia with central nervous system hypomyelination/vanishing white-matter disease leukodystrophy. The correlation we observed between the age at onset of the neurological deterioration and the severity of OF suggests a common pathophysiological pathway.  相似文献   

16.
BACKGROUND: The developmental environment is thought to determine, in part, lifelong metabolic parameters and risk of adult disease. Effects of maternal malnutrition on fetal growth have been studied extensively, and the role of poor prenatal diet in elevating lifelong risk of cardiovascular and metabolic disease has been well characterized ( www.thebarkertheory.com ). However, the contribution of gestational high saturated fat diet (HFD) to adult-onset metabolic disease and skeletal dysfunction has only recently been recognized, and as such is incompletely understood. METHODS: The present study evaluates the pathophysiologic mechanisms linking gestational HFD (approximating the macronutrient content of fast food) and elevated oxidative stress (OS) to adult-onset skeletal, cardiovascular, and metabolic dysfunction. RESULTS: Results of this study demonstrate that adult offspring of dams fed HFD during pregnancy exhibited adult hyperglycemia, insulin resistance, obesity, and hypertension, despite being fed healthy standard rodent chow throughout postnatal life. These offspring also showed significantly lower femoral epiphyseal average bone mineral density (ABMD) at 6 months of age, and dysregulation of distal femoral trabecular architecture at 12 months of age, characteristic of osteoporosis. Incidence of these adult-onset adverse skeletal and metabolic effects was reduced by supplementing the pregnant dam with the antioxidant (quercetin, Q) during pregnancy. CONCLUSIONS: Collectively, these data suggest that offspring of dams who consume a diet rich in saturated fats during pregnancy are at increased risk of adult-onset chronic disease. Additionally, these chronic diseases were determined to be in-part OS-mediated, and preventable by increasing a prenatal dietary antioxidant; this knowledge offers both a putative mechanism of disease pathogenesis and suggests a potential preventive strategy. Birth Defects Res (Part B) 86:377–384, 2009. © 2009 Wiley-Liss, Inc.  相似文献   

17.
There is increasing evidence that amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) lie on a clinical, pathological and genetic continuum with patients of one disease exhibiting features of the other. Nevertheless, to date, the underlying grey matter and white matter changes across the ALS-FTD disease continuum have not been explored. In this study fifty-three participants with ALS (n = 10), ALS-FTD (n = 10) and behavioural variant FTD (bvFTD; n = 15) as well as controls (n = 18), underwent detailed clinical assessment plus structural imaging using voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) analysis of magnetic resonance brain imaging to examine grey and white matter differences and commonalities across the continuum. Importantly, patient groups were matched for age, education, gender and disease duration. VBM and DTI results showed that changes in the ALS group were confined mainly to the motor cortex and anterior cingulate as well as their underlying white matter tracts. ALS-FTD and bvFTD showed widespread grey matter and white matter changes involving frontal and temporal lobes. Extensive prefrontal cortex changes emerged as a marker for bvFTD compared to other subtypes, while ALS-FTD could be distinguished from ALS by additional temporal lobe grey and white matter changes. Finally, ALS could be mainly distinguished from the other two groups by corticospinal tract degeneration. The present study shows for the first time that FTD and ALS overlap in anterior cingulate, motor cortex and related white matter tract changes across the whole continuum. Nevertheless, frontal and temporal atrophy as well as corticospinal tract degeneration emerged as marker for subtype classification, which will inform future diagnosis and target disease management across the continuum.  相似文献   

18.
Two cDNAs (At.EIF4E1 and At.EIF4E2) encoding, respectively, the eukaryotic initiation factors eIF4E and eIF(iso)4E of Arabidopsis thaliana were isolated by complementation of a Saccharomyces cerevisiae conditional mutant. The deduced amino acid sequences of the proteins are homologous to those from monocotyledonous plants, yeast and mammals. The corresponding genes were identified in YAC clones mapping to chromosome IV (At.EIF4E1) and to chromosome V (At.EIF4E2). The yeast strain complemented by At.EIF4E2 grew poorly compared with an isogenic strain expressing At.EIF4E1. Northern and in situ hybridization analysis show that both Arabidopsis At.EIF4E1 and At.EIF4E2 mRNAs are differentially accumulated in plant tissues. The At.EIF4E1 mRNA is expressed in all tissues except in the cells of the specialization zone of the roots; the At.EIF4E2 mRNA is particularly abundant in floral organs and in young developing tissues. This work further demonstrates an association between a high level of EIF4E mRNAs and cell proliferation and suggests that the plant eIF4E isoforms may have distinct functions in cell development and metabolism.  相似文献   

19.
High adiposity is deleteriously associated with brain health, and may disproportionately affect white matter integrity; however, limited information exists regarding the mechanisms underlying the association between body mass (BMI) and white matter integrity. The present study evaluated whether vascular and inflammatory markers influence the relationship between BMI and white matter in healthy aging. We conducted a cross-sectional evaluation of white matter integrity, BMI, and vascular/inflammatory factors in a cohort of 138 healthy older adults (mean age: 71.3 years). Participants underwent diffusion tensor imaging, provided blood samples, and participated in a health evaluation. Vascular risk factors and vascular/inflammatory blood markers were assessed. The primary outcome measure was fractional anisotropy (FA) of the genu, body, and splenium (corpus callosum); exploratory measures included additional white matter regions, based on significant associations with BMI. Regression analyses indicated that higher BMI was associated with lower FA in the corpus callosum, cingulate, and fornix (p<.001). Vascular and inflammatory factors influenced the association between BMI and FA. Specifically, BMI was independently associated with the genu [β=-.21; B=-.0024; 95% CI, -.0048 to -.0000; p=.05] and cingulate fibers [β=-.39; B=-.0035; 95% CI,-.0056 to -.0015; p<.001], even after controlling for vascular/inflammatory risk factors and blood markers. In contrast, BMI was no longer significantly associated with the fornix and middle/posterior regions of the corpus callosum after controlling for these markers. Results partially support a vascular/inflammatory hypothesis, but also suggest a more complex relationship between BMI and white matter characterized by potentially different neuroanatomic vulnerability.  相似文献   

20.
ObjectiveEIF4EBP1 acts as a crucial effector in mTOR signaling pathway. Studies have suggested that EIF4EBP1 plays a critical role in carcinogenesis. However, the clinical significance and biological role of EIF4EBP1 in hepatocellular carcinoma (HCC) have not been elucidated. Therefore, we aimed to investigate the clinical significance of EIF4EBP1 in HCC.MethodsTotal 128 cases of HCCs were included in this study. EIF4EBP1 expression in HCC tissues was detected by qRT-PCR, Western blot and immunohistochemistry, respectively. Then the relationships between EIF4EBP1 expression and clinical features as well as survival were analyzed.ResultsThe expression level of EIF4EBP1 mRNA is significantly higher in 60% (24/40) of fresh HCC tissues than that in the matched adjacent nontumor liver (NCL) tissues (P = 0.044). Similarly, EIF4EBP1 protein is notably upregulated in 8 HCC tissues (randomly selected from the 40 HCCs) measured by Western blot and is significantly increased in another 88 paraffin-embedded HCCs (53%, 47/88) by immunohistochemistry compared with the matched NCLs (P < 0.001). EIF4EBP1 protein expression in HCC tissues is significantly correlated with serum AFP (P = 0.003) and marginally significantly associated with pathological grade (P = 0.085), tumor number (P = 0.084), tumor embolus (P = 0.084) and capsulation (P = 0.073). Patients with higher EIF4EBP1 protein expression have a much worse 5-year overall survival (40.3% vs 73.6%) and 5-year disease-free survival (33.0% vs 49.0%) than those with low expression. Furthermore, Cox regression analysis shows that EIF4EBP1 protein is an independent prognostic factor for overall survival (HR, 2.285; 95% CI, 1.154–4.527; P = 0.018) and disease-free survival (HR, 1.901; 95% CI, 1.067–3.386; P = 0.029) in HCC patients.ConclusionsOur results demonstrate for the first time that EIF4EBP1 mRNA and protein are markedly up-regulated in HCC tissues, and the protein overexpression is significantly associated with poor survival and progression, which provide a potential new prognostic marker and therapeutic target for HCC patients.  相似文献   

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