RESUMO
AIMS: Glioneuronal tumours (GNTs) are poorly distinguished by their histology and lack robust diagnostic indicators. Previously, we showed that common GNTs comprise two molecularly distinct groups, correlating poorly with histology. To refine diagnosis, we constructed a methylation-based model for GNT classification, subsequently evaluating standards for molecular stratification by methylation, histology and radiology. METHODS: We comprehensively analysed methylation, radiology and histology for 83 GNT samples: a training cohort of 49, previously classified into molecularly defined groups by genomic profiles, plus a validation cohort of 34. We identified histological and radiological correlates to molecular classification and constructed a methylation-based support vector machine (SVM) model for prediction. Subsequently, we contrasted methylation, radiological and histological classifications in validation GNTs. RESULTS: By methylation clustering, all training and 23/34 validation GNTs segregated into two groups, the remaining 11 clustering alongside control cortex. Histological review identified prominent astrocytic/oligodendrocyte-like components, dysplastic neurons and a specific glioneuronal element as discriminators between groups. However, these were present in only a subset of tumours. Radiological review identified location, margin definition, enhancement and T2 FLAIR-rim sign as discriminators. When validation GNTs were classified by SVM, 22/23 classified correctly, comparing favourably against histology and radiology that resolved 17/22 and 15/21, respectively, where data were available for comparison. CONCLUSIONS: Diagnostic criteria inadequately reflect glioneuronal tumour biology, leaving a proportion unresolvable. In the largest cohort of molecularly defined glioneuronal tumours, we develop molecular, histological and radiological approaches for biologically meaningful classification and demonstrate almost all cases are resolvable, emphasising the importance of an integrated diagnostic approach.
Assuntos
Neoplasias Encefálicas , Neoplasias do Sistema Nervoso Central , Neoplasias Neuroepiteliomatosas , Radiologia , Humanos , Neoplasias Encefálicas/patologia , Metilação de DNA , Neoplasias Neuroepiteliomatosas/genética , Neoplasias do Sistema Nervoso Central/genéticaRESUMO
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder with a high degree of comorbidity, including substance misuse. We aimed to assess whether ADHD polygenic risk scores (PRS) could predict ADHD diagnosis in alcohol dependence (AD). ADHD PRS were generated for 1223 AD subjects with ADHD diagnosis information and 1818 healthy controls. ADHD PRS distributions were compared to evaluate the differences between healthy controls and AD cases with and without ADHD. We found increased ADHD PRS means in the AD cohort with ADHD (mean 0.30, standard deviation (SD) 0.92; p = 3.9 × 10-6 ); and without ADHD (mean - 0.00, SD 1.00; p = 5.2 × 10-5 ) compared to the healthy control subjects (mean - 0.17, SD 0.99). The ADHD PRS means differed within the AD group with a higher ADHD PRS mean in those with ADHD, odds ratio (OR) 1.34, confidence interval (CI) 1.10 to 1.65; p = 0.002. This study showed a positive relationship between ADHD PRS and risk of ADHD in individuals with co-occurring AD indicating that ADHD PRS may have utility in identifying individuals that are at a higher or lower risk of ADHD. Further larger studies need to be conducted to confirm the reliability of the results before ADHD PRS can be considered as a robust biomarker for diagnosis.
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BACKGROUND: Steroid-sensitive nephrotic syndrome (SSNS), the most common form of nephrotic syndrome in childhood, is considered an autoimmune disease with an established classic HLA association. However, the precise etiology of the disease is unclear. In other autoimmune diseases, the identification of loci outside the classic HLA region by genome-wide association studies (GWAS) has provided critical insights into disease pathogenesis. Previously conducted GWAS of SSNS have not identified non-HLA loci achieving genome-wide significance. METHODS: In an attempt to identify additional loci associated with SSNS, we conducted a GWAS of a large cohort of European ancestry comprising 422 ethnically homogeneous pediatric patients and 5642 ethnically matched controls. RESULTS: The GWAS found three loci that achieved genome-wide significance, which explain approximately 14% of the genetic risk for SSNS. It confirmed the previously reported association with the HLA-DR/DQ region (lead single-nucleotide polymorphism [SNP] rs9273542, P=1.59×10-43; odds ratio [OR], 3.39; 95% confidence interval [95% CI], 2.86 to 4.03) and identified two additional loci outside the HLA region on chromosomes 4q13.3 and 6q22.1. The latter contains the calcium homeostasis modulator family member 6 gene CALHM6 (previously called FAM26F). CALHM6 is implicated in immune response modulation; the lead SNP (rs2637678, P=1.27×10-17; OR, 0.51; 95% CI, 0.44 to 0.60) exhibits strong expression quantitative trait loci effects, the risk allele being associated with lower lymphocytic expression of CALHM6. CONCLUSIONS: Because CALHM6 is implicated in regulating the immune response to infection, this may provide an explanation for the typical triggering of SSNS onset by infections. Our results suggest that a genetically conferred risk of immune dysregulation may be a key component in the pathogenesis of SSNS.
Assuntos
Canais de Cálcio/genética , Glicoproteínas de Membrana/genética , Síndrome Nefrótica/genética , Esteroides/uso terapêutico , Alelos , Proteína de Ligação a Androgênios/genética , Criança , Bases de Dados Factuais , Epitopos/química , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Genótipo , Cadeias alfa de HLA-DQ/genética , Cadeias beta de HLA-DQ/genética , Cadeias HLA-DRB1/genética , Humanos , Sistema Imunitário , Masculino , Síndrome Nefrótica/tratamento farmacológico , Razão de Chances , Peptídeos/química , Polimorfismo de Nucleotídeo Único , Locos de Características QuantitativasRESUMO
Glioneuronal tumours are an important cause of treatment-resistant epilepsy. Subtypes of tumour are often poorly discriminated by histological features and may be difficult to diagnose due to a lack of robust diagnostic tools. This is illustrated by marked variability in the reported frequencies across different epilepsy surgical series. To address this, we used DNA methylation arrays and RNA sequencing to assay the methylation and expression profiles within a large cohort of glioneuronal tumours. By adopting a class discovery approach, we were able to identify two distinct groups of glioneuronal tumour, which only partially corresponded to the existing histological classification. Furthermore, by additional molecular analyses, we were able to identify pathogenic mutations in BRAF and FGFR1, specific to each group, in a high proportion of cases. Finally, by interrogating our expression data, we were able to show that each molecular group possessed expression phenotypes suggesting different cellular differentiation: astrocytic in one group and oligodendroglial in the second. Informed by this, we were able to identify CCND1, CSPG4, and PDGFRA as immunohistochemical targets which could distinguish between molecular groups. Our data suggest that the current histological classification of glioneuronal tumours does not adequately represent their underlying biology. Instead, we show that there are two molecular groups within glioneuronal tumours. The first of these displays astrocytic differentiation and is driven by BRAF mutations, while the second displays oligodendroglial differentiation and is driven by FGFR1 mutations.
Assuntos
Neoplasias Encefálicas/metabolismo , Epilepsia/metabolismo , Ganglioglioma/metabolismo , Neoplasias Neuroepiteliomatosas/metabolismo , Adolescente , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/cirurgia , Criança , Pré-Escolar , Estudos de Coortes , Metilação de DNA , Epilepsia/genética , Epilepsia/patologia , Epilepsia/cirurgia , Feminino , Ganglioglioma/genética , Ganglioglioma/patologia , Ganglioglioma/cirurgia , Expressão Gênica , Humanos , Lactente , Masculino , Mutação , Neoplasias Neuroepiteliomatosas/genética , Neoplasias Neuroepiteliomatosas/patologia , Neoplasias Neuroepiteliomatosas/cirurgia , Fenótipo , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas B-raf/metabolismo , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/metabolismoRESUMO
Prion diseases are associated with the conversion of cellular prion protein (PrP(C)) to toxic ß-sheet isoforms (PrP(Sc)), which are reported to inhibit the ubiquitin-proteasome system (UPS). Accordingly, UPS substrates accumulate in prion-infected mouse brains, suggesting impairment of the 26S proteasome. A direct interaction between its 20S core particle and PrP isoforms was demonstrated by immunoprecipitation. ß-PrP aggregates associated with the 20S particle, but did not impede binding of the PA26 complex, suggesting that the aggregates do not bind to its ends. Aggregated ß-PrP reduced the 20S proteasome's basal peptidase activity, and the enhanced activity induced by C-terminal peptides from the 19S ATPases or by the 19S regulator itself, including when stimulated by polyubiquitin conjugates. However, the 20S proteasome was not inhibited when the gate in the α-ring was open due to a truncation mutation or by association with PA26/PA28. These PrP aggregates inhibit by stabilising the closed conformation of the substrate entry channel. A similar inhibition of substrate entry into the proteasome may occur in other neurodegenerative diseases where misfolded ß-sheet-rich proteins accumulate.
Assuntos
Proteínas PrPSc/metabolismo , Inibidores de Proteassoma , Mapeamento de Interação de Proteínas , Animais , Humanos , Imunoprecipitação , Camundongos , Camundongos Transgênicos , Modelos Moleculares , Ligação ProteicaRESUMO
BACKGROUND: Individuals genetically susceptible to high schistosomiasis worm burden may contribute disproportionately to transmission and could be prioritized for control. Identifying genes involved may guide development of therapy. METHODOLOGY/PRINCIPAL FINDINGS: A cohort of 606 children aged 10-15 years were recruited in the Albert Nile region of Uganda and assessed for Schistosoma mansoni worm burden using the Up-Converting Particle Lateral Flow (UCP-LF) test detecting circulating anodic antigen (CAA), point-of-care Circulating Cathodic Antigen (POC-CCA) and Kato-Katz tests. Whole genome genotyping was conducted on 326 children comprising the top and bottom 25% of worm burden. Linear models were fitted to identify variants associated with worm burden in preselected candidate genes. Expression quantitative trait locus (eQTL) analysis was conducted for candidate genes with UCP-LF worm burden included as a covariate. Single Nucleotide Polymorphism loci associated with UCP-LF CAA included IL6 rs2066992 (OR = 0.43, p = 0.0006) and rs7793163 (OR = 2.0, p = 0.0007); IL21 SNP kgp513476 (OR 1.79, p = 0.0025) and IL17B SNP kgp708159 (OR = 0.35, p = 0.0028). A haplotype in the IL10 locus was associated with lower worm burden (OR = 0.53, p = 0.015) and overlapped SNPs rs1800896, rs1800871 and rs1800872. Significant haplotypes (p<0.05, overlapping significant SNP) associated with worm burden were observed in IL6 and the Th17 pathway IL12B and IL17B genes. There were significant eQTL in the IL6, IL5, IL21, IL25 and IFNG regions. CONCLUSIONS: Variants associated with S. mansoni worm burden were in IL6, FCN2, RNASE3, IL10, IL12B and IL17B gene loci. However only eQTL associations remained significant after Bonferroni correction. In summary, immune balance, pathogen recognition and Th17 pathways may play a role in modulating Schistosoma worm burden. Individuals carrying risk variants may be targeted first in allocation of control efforts to reduce the burden of schistosomiasis in the community.
Assuntos
Esquistossomose mansoni , Esquistossomose , Adolescente , Animais , Criança , Humanos , Antígenos de Helmintos , Proteína Catiônica de Eosinófilo , Fezes/química , Interleucina-10 , Subunidade p40 da Interleucina-12 , Interleucina-6/genética , Schistosoma mansoni/genética , Esquistossomose/diagnóstico , Esquistossomose mansoni/epidemiologia , Esquistossomose mansoni/diagnóstico , Sensibilidade e Especificidade , Uganda/epidemiologiaRESUMO
The vast majority of epithelial ovarian cancer arises from tissues that are embryologically derived from the Müllerian Duct. Here, we demonstrate that a DNA methylation signature in easy-to-access Müllerian Duct-derived cervical cells from women with and without ovarian cancer (i.e. referred to as the Women's risk IDentification for Ovarian Cancer index or WID-OC-index) is capable of identifying women with an ovarian cancer in the absence of tumour DNA with an AUC of 0.76 and women with an endometrial cancer with an AUC of 0.81. This and the observation that the cervical cell WID-OC-index mimics the epigenetic program of those cells at risk of becoming cancerous in BRCA1/2 germline mutation carriers (i.e. mammary epithelium, fallopian tube fimbriae, prostate) further suggest that the epigenetic misprogramming of cervical cells is an indicator for cancer predisposition. This concept has the potential to advance the field of risk-stratified cancer screening and prevention.
Assuntos
Colo do Útero/metabolismo , Metilação de DNA , Epitélio/metabolismo , Neoplasias Ovarianas/genética , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Proteína BRCA2/genética , Proteína BRCA2/metabolismo , Colo do Útero/citologia , Epigenoma , Feminino , Predisposição Genética para Doença , Humanos , Neoplasias Ovarianas/metabolismoRESUMO
Developing sympathetic neurons depend on NGF for survival. When sympathetic neurons are deprived of NGF in vitro, a well documented series of events, including c-Jun N-terminal kinase (JNK) pathway activation, release of cytochrome c from the mitochondria, and caspase activation, culminates in the death of the neuron by apoptosis within 24-48 h. This process requires de novo gene expression, suggesting that increased expression of specific genes activates the cell death program. Using rat gene microarrays, we found that NGF withdrawal induces the expression of many genes, including mkp1, which encodes a MAPK phosphatase that can dephosphorylate JNKs. The increase in mkp1 mRNA level requires the MLK-JNK-c-Jun pathway, and we show that Mkp1 is an important regulator of JNK-dependent apoptosis in sympathetic neurons. In microinjection experiments, Mkp1 overexpression can inhibit JNK-mediated phosphorylation of c-Jun and protect sympathetic neurons from apoptosis, while Mkp1 knockdown accelerates NGF withdrawal-induced death. Accordingly, the number of superior cervical ganglion (SCG) neurons is reduced in mkp1-/- mice at P1 during the period of developmental sympathetic neuron death. We also show that c-Jun and ATF2 bind to two conserved ATF binding sites in the mkp1 promoter in vitro and in chromatin. Both of these ATF sites contribute to basal promoter activity and are required for mkp1 promoter induction after NGF withdrawal. These results demonstrate that Mkp1 is part of a negative feedback loop induced by the MLK-JNK-c-Jun signaling pathway that modulates JNK activity and the rate of neuronal death in rat sympathetic neurons following NGF withdrawal.
Assuntos
Apoptose/fisiologia , Fosfatase 1 de Especificidade Dupla/genética , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Transdução de Sinais/genética , Gânglio Cervical Superior/citologia , Animais , Animais Recém-Nascidos , Apoptose/genética , Carbazóis/farmacologia , Células Cultivadas , Imunoprecipitação da Cromatina/métodos , Fosfatase 1 de Especificidade Dupla/deficiência , Ensaio de Desvio de Mobilidade Eletroforética/métodos , Eletroporação/métodos , Inibidores Enzimáticos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/fisiologia , Proteínas Quinases JNK Ativadas por Mitógeno/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microinjeções/métodos , Mutação/genética , Fator de Crescimento Neural/metabolismo , Fator de Crescimento Neural/farmacologia , Neurônios , Ligação Proteica/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , RNA Interferente Pequeno/farmacologia , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacosRESUMO
BACKGROUND: Developing sympathetic neurons depend on nerve growth factor (NGF) for survival and die by apoptosis after NGF withdrawal. This process requires de novo gene expression but only a small number of genes induced by NGF deprivation have been identified so far, either by a candidate gene approach or in mRNA differential display experiments. This is partly because it is difficult to obtain large numbers of sympathetic neurons for in vitro studies. Here, we describe for the first time, how advances in gene microarray technology have allowed us to investigate the expression of all known genes in sympathetic neurons cultured in the presence and absence of NGF. RESULTS: We have used Affymetrix Exon arrays to study the pattern of expression of all known genes in NGF-deprived sympathetic neurons. We identified 415 up- and 813 down-regulated genes, including most of the genes previously known to be regulated in this system. NGF withdrawal activates the mixed lineage kinase (MLK)-c-Jun N-terminal kinase (JNK)-c-Jun pathway which is required for NGF deprivation-induced death. By including a mixed lineage kinase (MLK) inhibitor, CEP-11004, in our experimental design we identified which of the genes induced after NGF withdrawal are potential targets of the MLK-JNK-c-Jun pathway. A detailed Gene Ontology and functional enrichment analysis also identified genetic pathways that are highly enriched and overrepresented amongst the genes expressed after NGF withdrawal. Five genes not previously studied in sympathetic neurons - trib3, ddit3, txnip, ndrg1 and mxi1 - were validated by real time-PCR. The proteins encoded by these genes also increased in level after NGF withdrawal and this increase was prevented by CEP-11004, suggesting that these genes are potential targets of the MLK-JNK-c-Jun pathway. CONCLUSIONS: The sympathetic neuron model is one of the best studied models of neuronal apoptosis. Overall, our microarray data gives a comprehensive overview of, and provides new information about, signalling pathways and transcription factors that are regulated by NGF withdrawal.
Assuntos
Morte Celular/genética , Perfilação da Expressão Gênica , Fator de Crescimento Neural/metabolismo , Neurônios/metabolismo , Sistema Nervoso Simpático/metabolismo , Animais , Sítios de Ligação , Regulação para Baixo , Éxons , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-jun/metabolismo , Ratos , Reação em Cadeia da Polimerase em Tempo Real , Sistema Nervoso Simpático/citologia , Regulação para CimaRESUMO
BACKGROUND: Apoptosis plays a critical role during neuronal development and disease. Developing sympathetic neurons depend on nerve growth factor (NGF) for survival during the late embryonic and early postnatal period and die by apoptosis in its absence. The proapoptotic BH3-only protein Bim increases in level after NGF withdrawal and is required for NGF withdrawal-induced death. The regulation of Bim expression in neurons is complex and this study describes a new mechanism by which an NGF-activated signalling pathway regulates bim gene expression in sympathetic neurons. RESULTS: We report that U0126, an inhibitor of the prosurvival MEK-ERK pathway, increases bim mRNA levels in sympathetic neurons in the presence of NGF. We find that this effect is independent of PI3-K-Akt and JNK-c-Jun signalling and is not mediated by the promoter, first exon or first intron of the bim gene. By performing 3' RACE and microinjection experiments with a new bim-LUC+3'UTR reporter construct, we show that U0126 increases bim expression via the bim 3' UTR. We demonstrate that this effect does not involve a change in bim mRNA stability and by using PD184352, a specific MEK1/2-ERK1/2 inhibitor, we show that this mechanism involves the MEK1/2-ERK1/2 pathway. Finally, we demonstrate that inhibition of MEK/ERK signalling independently reduces cell survival in NGF-treated sympathetic neurons. CONCLUSIONS: These results suggest that in sympathetic neurons, MEK-ERK signalling negatively regulates bim expression via the 3' UTR and that this regulation is likely to be at the level of transcription. This data provides further insight into the different mechanisms by which survival signalling pathways regulate bim expression in neurons.
Assuntos
Regiões 3' não Traduzidas/genética , Proteínas Reguladoras de Apoptose/fisiologia , Sistema de Sinalização das MAP Quinases/fisiologia , Proteínas de Membrana/fisiologia , Proteínas Proto-Oncogênicas/fisiologia , Transdução de Sinais/fisiologia , Sistema Nervoso Simpático/metabolismo , Animais , Animais Recém-Nascidos , Proteína 11 Semelhante a Bcl-2 , Células Cultivadas , Regulação para Baixo/fisiologia , Regulação da Expressão Gênica/fisiologia , Ratos , Ratos Sprague-DawleyRESUMO
The death of sympathetic neurons after nerve growth factor (NGF) withdrawal requires de novo gene expression. Dp5 was one of the first NGF withdrawal-induced genes to be identified and it encodes a proapoptotic BH3-only member of the Bcl-2 family. To study how dp5 transcription is regulated by NGF withdrawal we cloned the regulatory regions of the rat dp5 gene and constructed a series of dp5-luciferase reporter plasmids. In microinjection experiments with sympathetic neurons we found that three regions of dp5 contribute to its induction after NGF withdrawal: the promoter, a conserved region in the single intron, and sequences in the 3' untranslated region of the dp5 mRNA. A construct containing all three regions is efficiently activated by NGF withdrawal and, like the endogenous dp5, its induction requires mixed-lineage kinase (MLK) and c-Jun N-terminal kinase (JNK) activity. JNKs phosphorylate the AP-1 transcription factor c-Jun, and thereby increase its activity. We identified a conserved ATF site in the dp5 promoter that binds c-Jun and ATF2, which is critical for dp5 promoter induction after NGF withdrawal. These results suggest that part of the mechanism by which the MLK-JNK-c-Jun pathway promotes neuronal apoptosis is by activating the transcription of the dp5 gene.
Assuntos
Proteínas Reguladoras de Apoptose/genética , Regulação da Expressão Gênica , MAP Quinase Quinase 4/metabolismo , MAP Quinase Quinase Quinases/metabolismo , Neurônios/metabolismo , Neuropeptídeos/genética , Proteínas Proto-Oncogênicas c-jun/metabolismo , Regiões 3' não Traduzidas/química , Fator 2 Ativador da Transcrição/metabolismo , Animais , Proteínas Reguladoras de Apoptose/biossíntese , Sequência de Bases , Células Cultivadas , Humanos , Íntrons , MAP Quinase Quinase 4/antagonistas & inibidores , MAP Quinase Quinase Quinases/antagonistas & inibidores , Sistema de Sinalização das MAP Quinases , Camundongos , Dados de Sequência Molecular , Mutação , Fator de Crescimento Neural/fisiologia , Neurônios/enzimologia , Neuropeptídeos/biossíntese , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-jun/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Gânglio Cervical Superior/citologiaRESUMO
Immune-therapy is an attractive alternative therapeutic approach for targeting central nervous system (CNS) tumors and the constituency of the Tumor Immune Microenvironment (TIME) likely to predict patient response. Here, we describe the TIME of >6000 primarily pediatric CNS tumors using a deconvolution approach (methylCIBERSORT). We produce and validate a custom reference signature defining 11 non-cancer cell types to estimate relative proportions of infiltration in a panCNS tumor cohort spanning 80 subtypes. We group patients into three broad immune clusters associated with CNS tumor types/subtypes. In cohorts of medulloblastomas (n = 2325), malignant rhabdoid tumors (n = 229) and pediatric high-grade gliomas (n = 401), we show significant associations with molecular subgroups/subtypes, mutations, and prognosis. We further identify tumor-specific immune clusters with phenotypic characteristics relevant to immunotherapy response (i.e. Cytolytic score, PDL1 expression). Our analysis provides an indication of the potential future therapeutic and prognostic possibilities of immuno-methylomic profiling in pediatric CNS tumor patients that may ultimately inform approach to immune-therapy.
Assuntos
Neoplasias do Sistema Nervoso Central/imunologia , Neoplasias do Sistema Nervoso Central/terapia , Imunoterapia/métodos , Microambiente Tumoral/imunologia , Adolescente , Neoplasias do Sistema Nervoso Central/genética , Criança , Pré-Escolar , Estudos de Coortes , Glioma , Histonas/genética , Humanos , Leucócitos , Meduloblastoma/imunologia , Mutação , Prognóstico , Tumor RabdoideRESUMO
Infant high-grade gliomas appear clinically distinct from their counterparts in older children, indicating that histopathologic grading may not accurately reflect the biology of these tumors. We have collected 241 cases under 4 years of age, and carried out histologic review, methylation profiling, and custom panel, genome, or exome sequencing. After excluding tumors representing other established entities or subgroups, we identified 130 cases to be part of an "intrinsic" spectrum of disease specific to the infant population. These included those with targetable MAPK alterations, and a large proportion of remaining cases harboring gene fusions targeting ALK (n = 31), NTRK1/2/3 (n = 21), ROS1 (n = 9), and MET (n = 4) as their driving alterations, with evidence of efficacy of targeted agents in the clinic. These data strongly support the concept that infant gliomas require a change in diagnostic practice and management. SIGNIFICANCE: Infant high-grade gliomas in the cerebral hemispheres comprise novel subgroups, with a prevalence of ALK, NTRK1/2/3, ROS1, or MET gene fusions. Kinase fusion-positive tumors have better outcome and respond to targeted therapy clinically. Other subgroups have poor outcome, with fusion-negative cases possibly representing an epigenetically driven pluripotent stem cell phenotype.See related commentary by Szulzewsky and Cimino, p. 904.This article is highlighted in the In This Issue feature, p. 890.
Assuntos
Fusão Gênica/genética , Glioma/genética , Humanos , Lactente , Gradação de Tumores , Prognóstico , Resultado do TratamentoRESUMO
BACKGROUND: Marked variation exists in the use of genomic data in tumour diagnosis, and optimal integration with conventional diagnostic technology remains uncertain despite several studies reporting improved diagnostic accuracy, selection for targeted treatments, and stratification for trials. Our aim was to assess the added value of molecular profiling in routine clinical practice and the impact on conventional and experimental treatments. METHODS: This population-based study assessed the diagnostic and clinical use of DNA methylation-based profiling in childhood CNS tumours using two large national cohorts in the UK. In the diagnostic cohort-which included routinely diagnosed CNS tumours between Sept 1, 2016, and Sept 1, 2018-we assessed how the methylation profile altered or refined diagnosis in routine clinical practice and estimated how this would affect standard patient management. For the archival cohort of diagnostically difficult cases, we established how many cases could be solved using modern standard pathology, how many could only be solved using the methylation profile, and how many remained unsolvable. FINDINGS: Of 484 patients younger than 20 years with CNS tumours, 306 had DNA methylation arrays requested by the neuropathologist and were included in the diagnostic cohort. Molecular profiling added a unique contribution to clinical diagnosis in 107 (35%; 95% CI 30-40) of 306 cases in routine diagnostic practice-providing additional molecular subtyping data in 99 cases, amended the final diagnosis in five cases, and making potentially significant predictions in three cases. We estimated that it could change conventional management in 11 (4%; 95% CI 2-6) of 306 patients. Among 195 historically difficult-to-diagnose tumours in the archival cohort, 99 (51%) could be diagnosed using standard methods, with the addition of methylation profiling solving a further 34 (17%) cases. The remaining 62 (32%) cases were unresolved despite specialist pathology and methylation profiling. INTERPRETATION: Together, these data provide estimates of the impact that could be expected from routine implementation of genomic profiling into clinical practice, and indicate limitations where additional techniques will be required. We conclude that DNA methylation arrays are a useful diagnostic adjunct for childhood CNS tumours. FUNDING: The Brain Tumour Charity, Children with Cancer UK, Great Ormond Street Hospital Children's Charity, Olivia Hodson Cancer Fund, Cancer Research UK, and the National Institute of Health Research.
Assuntos
Neoplasias do Sistema Nervoso Central/diagnóstico , Metilação de DNA/fisiologia , Regulação Neoplásica da Expressão Gênica/fisiologia , Terapia de Alvo Molecular , Biomarcadores Tumorais/genética , Neoplasias do Sistema Nervoso Central/genética , Neoplasias do Sistema Nervoso Central/terapia , Criança , Humanos , Estudos Retrospectivos , TelomeraseRESUMO
OBJECTIVE: We sought to characterize C9orf72 expansions in relation to genetic ancestry and age at onset (AAO) and to use these measures to discriminate the behavioral from the language variant syndrome in a large pan-European cohort of frontotemporal lobar degeneration (FTLD) cases. METHODS: We evaluated expansions frequency in the entire cohort (n = 1,396; behavioral variant frontotemporal dementia [bvFTD] [n = 800], primary progressive aphasia [PPA] [n = 495], and FTLD-motor neuron disease [MND] [n = 101]). We then focused on the bvFTD and PPA cases and tested for association between expansion status, syndromes, genetic ancestry, and AAO applying statistical tests comprising Fisher exact tests, analysis of variance with Tukey post hoc tests, and logistic and nonlinear mixed-effects model regressions. RESULTS: We found C9orf72 pathogenic expansions in 4% of all cases (56/1,396). Expansion carriers differently distributed across syndromes: 12/101 FTLD-MND (11.9%), 40/800 bvFTD (5%), and 4/495 PPA (0.8%). While addressing population substructure through principal components analysis (PCA), we defined 2 patients groups with Central/Northern (n = 873) and Southern European (n = 523) ancestry. The proportion of expansion carriers was significantly higher in bvFTD compared to PPA (5% vs 0.8% [p = 2.17 × 10-5; odds ratio (OR) 6.4; confidence interval (CI) 2.31-24.99]), as well as in individuals with Central/Northern European compared to Southern European ancestry (4.4% vs 1.8% [p = 1.1 × 10-2; OR 2.5; CI 1.17-5.99]). Pathogenic expansions and Central/Northern European ancestry independently and inversely correlated with AAO. Our prediction model (based on expansions status, genetic ancestry, and AAO) predicted a diagnosis of bvFTD with 64% accuracy. CONCLUSIONS: Our results indicate correlation between pathogenic C9orf72 expansions, AAO, PCA-based Central/Northern European ancestry, and a diagnosis of bvFTD, implying complex genetic risk architectures differently underpinning the behavioral and language variant syndromes.
Assuntos
Afasia Primária Progressiva/genética , Proteína C9orf72/genética , Degeneração Lobar Frontotemporal/genética , Idade de Início , Idoso , Idoso de 80 Anos ou mais , Afasia Primária Progressiva/fisiopatologia , Estudos de Coortes , Expansão das Repetições de DNA , Europa (Continente) , Feminino , Demência Frontotemporal/genética , Demência Frontotemporal/fisiopatologia , Degeneração Lobar Frontotemporal/fisiopatologia , Geografia , Humanos , Masculino , Região do Mediterrâneo , Pessoa de Meia-Idade , Análise de Componente Principal , Países Escandinavos e Nórdicos , SíndromeRESUMO
Recent studies have demonstrated genetic differences between monozygotic (MZ) twins. To test the hypothesis that early post-twinning mutational events associate with phenotypic discordance, we investigated a cohort of 13 twin pairs (n = 26) discordant for various clinical phenotypes using whole-exome sequencing and screened for copy number variation (CNV). We identified a de novo variant in PLCB1, a gene involved in the hydrolysis of lipid phosphorus in milk from dairy cows, associated with lactase non-persistence, and a variant in the mitochondrial complex I gene MT-ND5 associated with amyotrophic lateral sclerosis (ALS). We also found somatic variants in multiple genes (TMEM225B, KBTBD3, TUBGCP4, TFIP11) in another MZ twin pair discordant for ALS. Based on the assumption that discordance between twins could be explained by a common variant with variable penetrance or expressivity, we screened the twin samples for known pathogenic variants that are shared and identified a rare deletion overlapping ARHGAP11B, in the twin pair manifesting with either schizotypal personality disorder or schizophrenia. Parent-offspring trio analysis was implemented for two twin pairs to assess potential association of variants of parental origin with susceptibility to disease. We identified a de novo variant in RASD2 shared by 8-year-old male twins with a suspected diagnosis of autism spectrum disorder (ASD) manifesting as different traits. A de novo CNV duplication was also identified in these twins overlapping CD38, a gene previously implicated in ASD. In twins discordant for Tourette's syndrome, a paternally inherited stop loss variant was detected in AADAC, a known candidate gene for the disorder.
Assuntos
Esclerose Lateral Amiotrófica/genética , Transtorno do Espectro Autista/genética , Sequência de Bases , Variações do Número de Cópias de DNA , Deleção de Sequência , Síndrome de Tourette/genética , Gêmeos Monozigóticos/genética , Adolescente , Adulto , Idoso , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sequenciamento do ExomaRESUMO
Huntington's disease (HD) is caused by an expanded polyglutamine tract in the huntingtin protein. Mitochondrial dysfunction and free radical damage occur in both R6/2 mice and HD patient brains and might play a role in disease pathogenesis. In cell culture systems, heat-shock protein 27 (Hsp27), a small molecular chaperone, suppresses mutant huntingtin-induced reactive oxygen species formation and cell death. To investigate this in vivo, we conducted an extensive phenotypic characterization of mice arising from a cross between R6/2 mice and Hsp27 transgenic mice but did not observe an improvement of the R6/2 phenotype. Hsp27 overexpression had no effect in reducing oxidative stress in the R6/2 brain, assessed by measuring striatal aconitase activity and protein carbonylation levels. Native protein gel analysis revealed that transgenic Hsp27 forms active, large oligomeric species in heat-shocked brain lysates, demonstrating that it is efficiently activated upon stress. In contrast, Hsp27 in double transgenic brains exists predominantly as a low molecular weight, inactive species. This suggests that Hsp27, which is otherwise activatable upon heat shock, remains inactive in the R6/2 model of chronic neurodegeneration. Hsp27 transgenics had been previously shown to be protected from acute stresses such as kainate administration, ischemia/reperfusion heart injury and neonatal nerve injury. Our study is the first to suggest a differential modulation of Hsp27 activation in vivo and, importantly, it illustrates the diverse effect of Hsp27 on acute versus chronic models of disease.
Assuntos
Proteínas de Choque Térmico/genética , Doença de Huntington/genética , Degeneração Neural/genética , Aconitato Hidratase/metabolismo , Animais , Comportamento Animal , Western Blotting , Encéfalo/metabolismo , Encéfalo/patologia , Modelos Animais de Doenças , Feminino , Expressão Gênica , Genótipo , Proteínas de Choque Térmico/metabolismo , Resposta ao Choque Térmico/genética , Resposta ao Choque Térmico/fisiologia , Doença de Huntington/metabolismo , Doença de Huntington/fisiopatologia , Imuno-Histoquímica , Imunoprecipitação , Corpos de Inclusão/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Camundongos Knockout , Camundongos Transgênicos , Degeneração Neural/metabolismo , Degeneração Neural/fisiopatologia , Estresse Oxidativo , Fenótipo , Transglutaminases/genética , Transglutaminases/metabolismoRESUMO
Highly quantitative biomarkers of neurodegenerative disease remain an important need in the urgent quest for disease-modifying therapies. For Huntington's disease (HD), a genetic test is available (trait marker), but necessary state markers are still in development. In this report, we describe a large battery of transcriptomic tests explored as state biomarker candidates. In an attempt to exploit the known neuroinflammatory and transcriptional perturbations of disease, we measured relevant mRNAs in peripheral blood cells. The performance of these potential markers was weak overall, with only one mRNA, immediate early response 3 (IER3), showing a modest but significant increase of 32% in HD samples compared with controls. No statistically significant differences were found for any other mRNAs tested, including a panel of 12 RNA biomarkers identified in a previous report [Borovecki F, Lovrecic L, Zhou J, Jeong H, Then F, Rosas HD, Hersch SM, Hogarth P, Bouzou B, Jensen RV, et al. (2005) Proc Natl Acad Sci USA 102:11023-11028]. The present results may nonetheless inform the future design and testing of HD biomarker strategies.
Assuntos
Doença de Huntington/sangue , Doença de Huntington/genética , Membranas Intracelulares/metabolismo , Linfócitos/metabolismo , Transcrição Gênica/genética , Biomarcadores/sangue , Regulação da Expressão Gênica , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , RNA/genéticaRESUMO
The mechanism of cell death in prion disease is unknown but is associated with the production of a misfolded conformer of the prion protein. We report that disease-associated prion protein specifically inhibits the proteolytic beta subunits of the 26S proteasome. Using reporter substrates, fluorogenic peptides, and an activity probe for the beta subunits, this inhibitory effect was demonstrated in pure 26S proteasome and three different cell lines. By challenge with recombinant prion and other amyloidogenic proteins, we demonstrate that only the prion protein in a nonnative beta sheet conformation inhibits the 26S proteasome at stoichiometric concentrations. Preincubation with an antibody specific for aggregation intermediates abrogates this inhibition, consistent with an oligomeric species mediating this effect. We also present evidence for a direct relationship between prion neuropathology and impairment of the ubiquitin-proteasome system (UPS) in prion-infected UPS-reporter mice. Together, these data suggest a mechanism for intracellular neurotoxicity mediated by oligomers of misfolded prion protein.
Assuntos
Príons/química , Príons/toxicidade , Inibidores de Proteassoma , Animais , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Linhagem Celular , Técnicas In Vitro , Camundongos , Camundongos Transgênicos , Degeneração Neural/enzimologia , Degeneração Neural/etiologia , Degeneração Neural/patologia , Proteínas PrPSc/química , Proteínas PrPSc/toxicidade , Doenças Priônicas/enzimologia , Doenças Priônicas/etiologia , Doenças Priônicas/patologia , Inibidores de Proteases/química , Inibidores de Proteases/toxicidade , Complexo de Endopeptidases do Proteassoma/química , Desnaturação Proteica , Estrutura Quaternária de Proteína , Subunidades Proteicas , Proteínas Recombinantes/química , Proteínas Recombinantes/toxicidade , Ubiquitina/metabolismoRESUMO
Huntington's disease (HD) causes widespread CNS changes and systemic abnormalities including endocrine and immune dysfunction. HD biomarkers are needed to power clinical trials of potential treatments. We used multiplatform proteomic profiling to reveal plasma changes with HD progression. Proteins of interest were evaluated using immunoblotting and ELISA in plasma from 2 populations, CSF and R6/2 mice. The identified proteins demonstrate neuroinflammation in HD and warrant further investigation as possible biomarkers.