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1.
Acta Neuropathol ; 147(1): 22, 2024 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-38265489

RESUMO

Ependymomas encompass multiple clinically relevant tumor types based on localization and molecular profiles. Tumors of the methylation class "spinal ependymoma" (SP-EPN) represent the most common intramedullary neoplasms in children and adults. However, their developmental origin is ill-defined, molecular data are scarce, and the potential heterogeneity within SP-EPN remains unexplored. The only known recurrent genetic events in SP-EPN are loss of chromosome 22q and NF2 mutations, but neither types and frequency of these alterations nor their clinical relevance have been described in a large, epigenetically defined series. Transcriptomic (n = 72), epigenetic (n = 225), genetic (n = 134), and clinical data (n = 112) were integrated for a detailed molecular overview on SP-EPN. Additionally, we mapped SP-EPN transcriptomes to developmental atlases of the developing and adult spinal cord to uncover potential developmental origins of these tumors. The integration of transcriptomic ependymoma data with single-cell atlases of the spinal cord revealed that SP-EPN display the highest similarities to mature adult ependymal cells. Unsupervised hierarchical clustering of transcriptomic data together with integrated analysis of methylation profiles identified two molecular SP-EPN subtypes. Subtype A tumors primarily carried previously known germline or sporadic NF2 mutations together with 22q loss (bi-allelic NF2 loss), resulting in decreased NF2 expression. Furthermore, they more often presented as multilocular disease and demonstrated a significantly reduced progression-free survival as compared to SP-EP subtype B. In contrast, subtype B predominantly contained samples without NF2 mutation detected in sequencing together with 22q loss (monoallelic NF2 loss). These tumors showed regular NF2 expression but more extensive global copy number alterations. Based on integrated molecular profiling of a large multi-center cohort, we identified two distinct SP-EPN subtypes with important implications for genetic counseling, patient surveillance, and drug development priorities.


Assuntos
Ependimoma , Neoplasias da Medula Espinal , Adulto , Criança , Humanos , Transcriptoma , Perfilação da Expressão Gênica , Mutação , Epigênese Genética
2.
Neuropathol Appl Neurobiol ; : e12949, 2023 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-38112165

RESUMO

AIM: Pilocytic astrocytomas (PA) in adults are rare and may be challenging to identify based only on histomorphology. Compared to their paediatric counterparts, they are reportedly molecularly more diverse and associated with a worse prognosis. We aimed to describe the characteristics of adult PAs more precisely by comprehensively profiling a series of 79 histologically diagnosed adult cases (≥18 years). METHODS: We performed global DNA methylation profiling and DNA and RNA panel sequencing, and integrated the results with clinical data. We further compared the molecular characteristics of adult and paediatric PAs that had a significant match to one of the established PA methylation classes in the Heidelberg brain tumour classifier. RESULTS: The mean age in our cohort was 33 years, and 43% of the tumours were located supratentorially. Based on methylation profiling, only 39% of the cases received a significant match to a PA methylation class. Sixteen per cent matched a different tumour type and 45% had a Heidelberg classifier score <0.9 with an affiliation to diverse established methylation classes in t-SNE analyses. Although the KIAA1549::BRAF fusion was found in 98% of paediatric PAs, this was true for only 27% of histologically defined and 55% of adult PAs defined by methylation profiling. CONCLUSIONS: A particularly high fraction of adult tumours with histological features of PA do not match current PA methylation classes, indicating ambiguous histology and an urgent need for molecular profiling. Moreover, even in adult PAs with a match to a PA methylation class, the distribution of genetic drivers differs significantly from their paediatric counterparts (p<0.01).

3.
Acta Neuropathol ; 144(4): 615-635, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35976433

RESUMO

Tauopathies such as progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) exhibit characteristic neuronal and glial inclusions of hyperphosphorylated Tau (pTau). Although the astrocytic pTau phenotype upon neuropathological examination is the most guiding feature in distinguishing both diseases, regulatory mechanisms controlling their transitions into disease-specific states are poorly understood to date. Here, we provide accessible chromatin data of more than 45,000 single nuclei isolated from the frontal cortex of PSP, CBD, and control individuals. We found a strong association of disease-relevant molecular changes with astrocytes and demonstrate that tauopathy-relevant genetic risk variants are tightly linked to astrocytic chromatin accessibility profiles in the brains of PSP and CBD patients. Unlike the established pathogenesis in the secondary tauopathy Alzheimer disease, microglial alterations were relatively sparse. Transcription factor (TF) motif enrichments in pseudotime as well as modeling of the astrocytic TF interplay suggested a common pTau signature for CBD and PSP that is reminiscent of an inflammatory immediate-early response. Nonetheless, machine learning models also predicted discriminatory features, and we observed marked differences in molecular entities related to protein homeostasis between both diseases. Predicted TF involvement was supported by immunofluorescence analyses in postmortem brain tissue for their highly correlated target genes. Collectively, our data expand the current knowledge on risk gene involvement (e.g., MAPT, MAPK8, and NFE2L2) and molecular pathways leading to the phenotypic changes associated with CBD and PSP.


Assuntos
Degeneração Corticobasal , Paralisia Supranuclear Progressiva , Tauopatias , Astrócitos/patologia , Cromatina , Humanos , Paralisia Supranuclear Progressiva/patologia , Tauopatias/genética , Tauopatias/patologia , Proteínas tau/genética , Proteínas tau/metabolismo
4.
J Neurooncol ; 156(2): 317-327, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34902093

RESUMO

INTRODUCTION: The cIMPACT-NOW update 6 first introduced glioblastoma diagnosis based on the combination of IDH-wildtype (IDHwt) status and TERT promotor mutation (pTERTmut). In glioblastoma as defined by histopathology according to the WHO 2016 classification, MGMT promotor status is associated with outcome. Whether this is also true in glioblastoma defined by molecular markers is yet unclear. METHODS: We searched the institutional database for patients with: (1) glioblastoma defined by histopathology; and (2) IDHwt astrocytoma with pTERTmut. MGMT promotor methylation was analysed using methylation-specific PCR and Sanger sequencing of CpG sites within the MGMT promotor region. RESULTS: We identified 224 patients with glioblastoma diagnosed based on histopathology, and 54 patients with IDHwt astrocytoma with pTERTmut (19 astrocytomas WHO grade II and 38 astrocytomas WHO grade III). There was no difference in the number of MGMT methylated tumors between the two cohorts as determined per PCR, and also neither the number nor the pattern of methylated CpG sites differed as determined per Sanger sequencing. Progression-free (PFS) and overall survival (OS) was similar between the two cohorts when treated with radio- or chemotherapy. In both cohorts, higher numbers of methylated CpG sites were associated with favourable outcome. CONCLUSIONS: Extent and pattern of methylated CpG sites are similar in glioblastoma and IDHwt astrocytoma with pTERTmut. In both tumor entities, higher numbers of methylated CpG sites appear associated with more favourable outcome. Evaluation in larger prospective cohorts is warranted.


Assuntos
Astrocitoma , Neoplasias Encefálicas , Metilases de Modificação do DNA , Enzimas Reparadoras do DNA , Glioblastoma , Proteínas Supressoras de Tumor , Astrocitoma/genética , Astrocitoma/patologia , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Metilação de DNA , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , Glioblastoma/genética , Glioblastoma/patologia , Humanos , Isocitrato Desidrogenase/genética , Mutação , Prognóstico , Regiões Promotoras Genéticas , Telomerase/genética , Proteínas Supressoras de Tumor/genética
5.
EMBO J ; 35(20): 2213-2222, 2016 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-27572463

RESUMO

Dynamic synapses facilitate activity-dependent remodeling of neural circuits, thereby providing the structural substrate for adaptive behaviors. However, the mechanisms governing dynamic synapses in adult brain are still largely unknown. Here, we demonstrate that in the cortex of adult amyloid precursor protein knockout (APP-KO) mice, spine formation and elimination were both reduced while overall spine density remained unaltered. When housed under environmental enrichment, APP-KO mice failed to respond with an increase in spine density. Spine morphology was also altered in the absence of APP The underlying mechanism of these spine abnormalities in APP-KO mice was ascribed to an impairment in D-serine homeostasis. Extracellular D-serine concentration was significantly reduced in APP-KO mice, coupled with an increase of total D-serine. Strikingly, chronic treatment with exogenous D-serine normalized D-serine homeostasis and restored the deficits of spine dynamics, adaptive plasticity, and morphology in APP-KO mice. The cognitive deficit observed in APP-KO mice was also rescued by D-serine treatment. These data suggest that APP regulates homeostasis of D-serine, thereby maintaining the constitutive and adaptive plasticity of dendritic spines in adult brain.


Assuntos
Precursor de Proteína beta-Amiloide/metabolismo , Encéfalo/metabolismo , Espinhas Dendríticas/metabolismo , Plasticidade Neuronal , Serina/metabolismo , Precursor de Proteína beta-Amiloide/genética , Animais , Transtornos Cognitivos/metabolismo , Feminino , Homeostase , Camundongos Knockout
6.
Acta Neuropathol ; 139(2): 305-318, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31679042

RESUMO

According to the WHO classification, ependymal tumors are classified as subependymomas, myxopapillary ependymomas, classic ependymomas, anaplastic ependymomas, and RELA-fusion-positive ependymomas (RELA-EPN). Among classic ependymomas, the WHO defines rare histological variants, i.e., the clear cell, papillary, and tanycytic ependymoma. In parallel, global DNA methylation patterns distinguish nine molecular groups, some of which tightly overlap with histopathological subgroups. However, the match of the aforementioned histological variants to DNA methylation classes remains unclear. We analyzed histomorphology, clinical parameters, and global DNA methylation of tumors with the initial histological diagnoses of tanycytic (n = 12), clear cell (n = 14), or papillary ependymoma (n = 19). Forty percent of these tumors did not match to the epigenetic profile of ependymomas, using a previously published DNA methylation-based classifier for brain tumors. Instead, they were classified as low-grade glioma (n = 3), plexus tumor (n = 2), CNS high-grade neuroepithelial tumor with MN1 alteration (n = 2), papillary tumor of the pineal region (n = 2), neurocytoma (n = 1), or did not match to any known brain tumor methylation class (n = 8). Overall, integrated diagnosis had to be changed in 35.6% of cases as compared to the initial diagnosis. Among the tumors molecularly classified as ependymoma (27/45 cases), tanycytic ependymomas were mostly located in the spine (5/7 cases) and matched to spinal or myxopapillary ependymoma. 6/8 clear cell ependymomas were found supratentorially and fell into the methylation class of RELA-EPN. Papillary ependymomas with a positive ependymoma match (12/19 cases) showed either a "papillary" (n = 5), a "trabecular" (n = 1), or a "pseudo-papillary" (n = 6) growth pattern. The papillary growth pattern was strongly associated with the methylation class B of posterior fossa ependymoma (PFB, 5/5 cases) and tumors displayed DNA methylation sites that were significantly different when compared to PFB ependymomas without papillary growth. Tumors with pseudo-papillary histology matched to the methylation class of myxopapillary ependymoma (4/6 cases), whereas the trabecular case was anatomically and molecularly a spinal ependymoma. Our results show that the diagnosis of histological ependymoma variants is challenging and epigenetic profiles may improve diagnostic accuracy of these cases. Whereas clear cell and papillary ependymomas display correlations between localization, histology, and methylation, tanycytic ependymoma does not represent a molecularly distinct subgroup.


Assuntos
Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Ependimoma/genética , Ependimoma/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Encefálicas/mortalidade , Criança , Estudos de Coortes , Metilação de DNA , Ependimoma/mortalidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Intervalo Livre de Progressão , Taxa de Sobrevida , Adulto Jovem
7.
Acta Neuropathol ; 138(6): 971-986, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31451907

RESUMO

Cognitive decline and dementia in neurodegenerative diseases are associated with synapse dysfunction and loss, which may precede neuron loss by several years. While misfolded and aggregated α-synuclein is recognized in the disease progression of synucleinopathies, the nature of glutamatergic synapse dysfunction and loss remains incompletely understood. Using fluorescence-activated synaptosome sorting (FASS), we enriched excitatory glutamatergic synaptosomes from mice overexpressing human alpha-synuclein (h-αS) and wild-type littermates to unprecedented purity. Subsequent label-free proteomic quantification revealed a set of proteins differentially expressed upon human alpha-synuclein overexpression. These include overrepresented proteins involved in the synaptic vesicle cycle, ER-Golgi trafficking, metabolism and cytoskeleton. Unexpectedly, we found and validated a steep reduction of eukaryotic translation elongation factor 1 alpha (eEF1A1) levels in excitatory synapses at early stages of h-αS mouse model pathology. While eEF1A1 reduction correlated with the loss of postsynapses, its immunoreactivity was found on both sides of excitatory synapses. Moreover, we observed a reduction in eEF1A1 immunoreactivity in the cingulate gyrus neuropil of patients with Lewy body disease along with a reduction in PSD95 levels. Altogether, our results suggest a link between structural impairments underlying cognitive decline in neurodegenerative disorders and local synaptic defects. eEF1A1 may therefore represent a limiting factor to synapse maintenance.


Assuntos
Fator 1 de Elongação de Peptídeos/metabolismo , Sinapses/metabolismo , Sinucleinopatias/metabolismo , Animais , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Biologia Computacional , Modelos Animais de Doenças , Proteína 4 Homóloga a Disks-Large/metabolismo , Feminino , Masculino , Camundongos Transgênicos , Neurópilo/metabolismo , Neurópilo/patologia , Proteoma , Sinapses/patologia , Sinucleinopatias/patologia , alfa-Sinucleína/genética , alfa-Sinucleína/metabolismo
8.
Acta Neuropathol ; 131(2): 235-246, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26724934

RESUMO

To successfully treat Alzheimer's disease (AD), pathophysiological events in preclinical stages need to be identified. Preclinical AD refers to the stages that exhibit amyloid deposition in the brain but have normal cognitive function, which are replicated in young adult APPswe/PS1deltaE9 (deltaE9) mice. By long-term in vivo two-photon microscopy, we demonstrate impaired adaptive spine plasticity in these transgenic mice illustrated by their failure to increase dendritic spine density and form novel neural connections when housed in enriched environment (EE). Decrease of amyloid plaques by reducing BACE1 activity restores the gain of spine density upon EE in deltaE9 mice, but not the remodeling of neural networks. On the other hand, anti-inflammatory treatment with pioglitazone or interleukin 1 receptor antagonist in deltaE9 mice successfully rescues the impairments in increasing spine density and remodeling of neural networks during EE. Our data suggest that neuroinflammation disrupts experience-dependent structural plasticity of dendritic spines in preclinical stages of AD.


Assuntos
Doença de Alzheimer/imunologia , Espinhas Dendríticas/imunologia , Neuroimunomodulação/imunologia , Plasticidade Neuronal/imunologia , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/patologia , Secretases da Proteína Precursora do Amiloide/genética , Secretases da Proteína Precursora do Amiloide/metabolismo , Animais , Anti-Inflamatórios/farmacologia , Ácido Aspártico Endopeptidases/genética , Ácido Aspártico Endopeptidases/metabolismo , Espinhas Dendríticas/efeitos dos fármacos , Espinhas Dendríticas/patologia , Modelos Animais de Doenças , Feminino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neuroimunomodulação/efeitos dos fármacos , Plasticidade Neuronal/efeitos dos fármacos , Pioglitazona , Células Piramidais/efeitos dos fármacos , Células Piramidais/imunologia , Células Piramidais/patologia , Receptores Tipo I de Interleucina-1/antagonistas & inibidores , Receptores Tipo I de Interleucina-1/metabolismo , Córtex Somatossensorial/efeitos dos fármacos , Córtex Somatossensorial/imunologia , Córtex Somatossensorial/patologia , Tiazolidinedionas/farmacologia
12.
Acta Neuropathol ; 130(1): 1-19, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26063233

RESUMO

Synaptic failure is an immediate cause of cognitive decline and memory dysfunction in Alzheimer's disease. Dendritic spines are specialized structures on neuronal processes, on which excitatory synaptic contacts take place and the loss of dendritic spines directly correlates with the loss of synaptic function. Dendritic spines are readily accessible for both in vitro and in vivo experiments and have, therefore, been studied in great detail in Alzheimer's disease mouse models. To date, a large number of different mechanisms have been proposed to cause dendritic spine dysfunction and loss in Alzheimer's disease. For instance, amyloid beta fibrils, diffusible oligomers or the intracellular accumulation of amyloid beta have been found to alter the function and structure of dendritic spines by distinct mechanisms. Furthermore, tau hyperphosphorylation and microglia activation, which are thought to be consequences of amyloidosis in Alzheimer's disease, may also contribute to spine loss. Lastly, genetic and therapeutic interventions employed to model the disease and elucidate its pathogenetic mechanisms in experimental animals may cause alterations of dendritic spines on their own. However, to date none of these mechanisms have been translated into successful therapeutic approaches for the human disease. Here, we critically review the most intensely studied mechanisms of spine loss in Alzheimer's disease as well as the possible pitfalls inherent in the animal models of such a complex neurodegenerative disorder.


Assuntos
Doença de Alzheimer/patologia , Espinhas Dendríticas/patologia , Doença de Alzheimer/fisiopatologia , Amiloide/metabolismo , Animais , Encéfalo/patologia , Encéfalo/fisiopatologia , Espinhas Dendríticas/fisiologia , Humanos
13.
Acta Neuropathol ; 129(6): 909-20, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25862638

RESUMO

Alzheimer's disease (AD) is thought to be caused by accumulation of amyloid-ß protein (Aß), which is a cleavage product of amyloid precursor protein (APP). Transgenic mice overexpressing APP have been used to recapitulate amyloid-ß pathology. Among them, APP23 and APPswe/PS1deltaE9 (deltaE9) mice are extensively studied. APP23 mice express APP with Swedish mutation and develop amyloid plaques late in their life, while cognitive deficits are observed in young age. In contrast, deltaE9 mice with mutant APP and mutant presenilin-1 develop amyloid plaques early but show typical cognitive deficits in old age. To unveil the reasons for different progressions of cognitive decline in these commonly used mouse models, we analyzed the number and turnover of dendritic spines as important structural correlates for learning and memory. Chronic in vivo two-photon imaging in apical tufts of layer V pyramidal neurons revealed a decreased spine density in 4-5-month-old APP23 mice. In age-matched deltaE9 mice, in contrast, spine loss was only observed on cortical dendrites that were in close proximity to amyloid plaques. In both cases, the reduced spine density was caused by decreased spine formation. Interestingly, the patterns of alterations in spine morphology differed between these two transgenic mouse models. Moreover, in APP23 mice, APP was found to accumulate intracellularly and its content was inversely correlated with the absolute spine density and the relative number of mushroom spines. Collectively, our results suggest that different pathological mechanisms, namely an intracellular accumulation of APP or extracellular amyloid plaques, may lead to spine abnormalities in young adult APP23 and deltaE9 mice, respectively. These distinct features, which may represent very different mechanisms of synaptic failure in AD, have to be taken into consideration when translating results from animal studies to the human disease.


Assuntos
Doença de Alzheimer/patologia , Precursor de Proteína beta-Amiloide/metabolismo , Espinhas Dendríticas/patologia , Mutação/genética , Neurônios/patologia , Presenilina-1/metabolismo , Doença de Alzheimer/genética , Precursor de Proteína beta-Amiloide/genética , Animais , Espinhas Dendríticas/metabolismo , Modelos Animais de Doenças , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Presenilina-1/genética , Estatísticas não Paramétricas
14.
Brain ; 137(Pt 12): 3319-26, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25281869

RESUMO

Cognitive decline in Alzheimer's disease is attributed to loss of functional synapses, most likely caused by synaptotoxic, oligomeric forms of amyloid-ß. Many treatment options aim at reducing amyloid-ß levels in the brain, either by decreasing its production or by increasing its clearance. We quantified the effects of immunotherapy directed against oligomeric amyloid-ß in Tg2576 mice, a mouse model of familial Alzheimer's disease. Treatment of 12-month-old mice with oligomer-specific (A-887755) or conformation-unspecific (6G1) antibodies for 8 weeks did not affect fibrillar plaque density or growth. We also quantified densities of DLG4 (previously known as PSD95) expressing post-synapses and synapsin expressing presynapses immunohistochemically. We found that both pre- and post-synapses were strongly reduced in the vicinity of plaques, whereas distant from plaques, in the cortex and hippocampal CA1 field, only post-synapses were reduced. Immunotherapy alleviated this synapse loss. Synapse loss was completely abolished distant from plaques, whereas it was only attenuated in the vicinity of plaques. These results suggest that fibrillar plaques may act as reservoirs for synaptotoxic, oligomeric amyloid-ß and that sequestering oligomers suffices to counteract synaptic pathology. Therefore, cognitive function may be improved by immunotherapy even when the load of fibrillar amyloid remains unchanged.


Assuntos
Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Imunoterapia , Placa Amiloide/patologia , Sinapses/patologia , Doença de Alzheimer/imunologia , Doença de Alzheimer/terapia , Animais , Transtornos Cognitivos/patologia , Modelos Animais de Doenças , Camundongos , Camundongos Transgênicos , Sinapses/metabolismo
15.
Dev Biol ; 374(2): 319-32, 2013 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-23237957

RESUMO

Wnt signaling is known to play crucial roles in the development of multiple organs as well as in cancer. In particular, constitutive activation of Wnt/ß-Catenin signaling in distinct populations of forebrain or brainstem precursor cells has previously been shown to result in dramatic brain enlargement during embryonic stages of development as well as in the formation of medulloblastoma, a malignant brain tumor in childhood. In order to extend this knowledge to postnatal stages of both cerebral and cerebellar cortex development, we conditionally activated Wnt signaling by introducing a dominant active form of ß-catenin in hGFAP-positive neural precursors. Such mutant mice survived up to 21 days postnatally. While the mice revealed enlarged ventricles and an initial expansion of the Pax6-positive ventricular zone, Pax6 expression and proliferative activity in the ventricular zone was virtually lost by embryonic day 16.5. Loss of Pax6 expression was not followed by expression of the subventricular zone marker Tbr2, indicating insufficient neuronal differentiation. In support of this finding, cortical thickness was severely diminished in all analyzed stages from embryonic day 14.5 to postnatal day 12, and appropriate layering was not detectable. Similarly, cerebella of hGFAP-cre::Ctnnb1(ex3)(Fl/+) mice were hypoplastic and displayed severe lamination defects. Constitutively active ß-Catenin induced inappropriate proliferation of granule neurons and inadequate development of Bergmann glia, thereby preventing regular migration of granule cells and normal cortical layering. We conclude that Wnt signaling has divergent roles in the central nervous system and that Wnt needs to be tightly controlled in a time- and cell type-specific manner.


Assuntos
Movimento Celular , Proliferação de Células , Sistema Nervoso Central/metabolismo , Células-Tronco Neurais/metabolismo , Neurônios/metabolismo , beta Catenina/metabolismo , Animais , Western Blotting , Encéfalo/embriologia , Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , Sistema Nervoso Central/embriologia , Sistema Nervoso Central/crescimento & desenvolvimento , Cerebelo/crescimento & desenvolvimento , Cerebelo/metabolismo , Proteína Glial Fibrilar Ácida/genética , Proteína Glial Fibrilar Ácida/metabolismo , Células HEK293 , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Camundongos , Camundongos Transgênicos , Microscopia Confocal , Neurônios/citologia , Fatores de Tempo , Técnicas de Cultura de Tecidos , Via de Sinalização Wnt , beta Catenina/genética
16.
Neuro Oncol ; 26(5): 935-949, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38158710

RESUMO

BACKGROUND: Embryonal tumors with multilayered rosettes (ETMR) are rare malignant embryonal brain tumors. The prognosis of ETMR is poor and novel therapeutic approaches are desperately needed. Comprehension of ETMR tumor biology is currently based on only few previous molecular studies, which mainly focused on the analyses of nucleic acids. In this study, we explored integrated ETMR proteomics. METHODS: Using mass spectrometry, proteome data were acquired from 16 ETMR and the ETMR cell line BT183. Proteome data were integrated with case-matched global DNA methylation data, publicly available transcriptome data, and proteome data of further embryonal and pediatric brain tumors. RESULTS: Proteome-based cluster analyses grouped ETMR samples according to histomorphology, separating neuropil-rich tumors with neuronal signatures from primitive tumors with signatures relating to stemness and chromosome organization. Integrated proteomics showcased that ETMR and BT183 cells harbor proteasome regulatory proteins in abundance, implicating their strong dependency on the proteasome machinery to safeguard proteostasis. Indeed, in vitro assays using BT183 highlighted that ETMR tumor cells are highly vulnerable toward treatment with the CNS penetrant proteasome inhibitor Marizomib. CONCLUSIONS: In summary, histomorphology stipulates the proteome signatures of ETMR, and proteasome regulatory proteins are pervasively abundant in these tumors. As validated in vitro, proteasome inhibition poses a promising therapeutic option in ETMR.


Assuntos
Neoplasias Encefálicas , Neoplasias Embrionárias de Células Germinativas , Complexo de Endopeptidases do Proteassoma , Proteômica , Humanos , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteômica/métodos , Neoplasias Embrionárias de Células Germinativas/metabolismo , Neoplasias Embrionárias de Células Germinativas/patologia , Neoplasias Embrionárias de Células Germinativas/genética , Neoplasias Embrionárias de Células Germinativas/tratamento farmacológico , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/genética , Proteoma/metabolismo , Proteoma/análise , Biomarcadores Tumorais/metabolismo , Biomarcadores Tumorais/genética , Inibidores de Proteassoma/farmacologia , Metilação de DNA
17.
Nat Commun ; 15(1): 6237, 2024 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-39043693

RESUMO

Medulloblastomas (MBs) are malignant pediatric brain tumors that are molecularly and clinically heterogenous. The application of omics technologies-mainly studying nucleic acids-has significantly improved MB classification and stratification, but treatment options are still unsatisfactory. The proteome and their N-glycans hold the potential to discover clinically relevant phenotypes and targetable pathways. We compile a harmonized proteome dataset of 167 MBs and integrate findings with DNA methylome, transcriptome and N-glycome data. We show six proteome MB subtypes, that can be assigned to two main molecular programs: transcription/translation (pSHHt, pWNT and pG3myc), and synapses/immunological processes (pSHHs, pG3 and pG4). Multiomic analysis reveals different conservation levels of proteome features across MB subtypes at the DNA methylome level. Aggressive pGroup3myc MBs and favorable pWNT MBs are most similar in cluster hierarchies concerning overall proteome patterns but show different protein abundances of the vincristine resistance-associated multiprotein complex TriC/CCT and of N-glycan turnover-associated factors. The N-glycome reflects proteome subtypes and complex-bisecting N-glycans characterize pGroup3myc tumors. Our results shed light on targetable alterations in MB and set a foundation for potential immunotherapies targeting glycan structures.


Assuntos
Meduloblastoma , Polissacarídeos , Proteoma , Meduloblastoma/metabolismo , Meduloblastoma/genética , Humanos , Polissacarídeos/metabolismo , Proteoma/metabolismo , Neoplasias Cerebelares/metabolismo , Neoplasias Cerebelares/genética , Metilação de DNA , Transcriptoma , Criança , Proteômica/métodos , Feminino , Regulação Neoplásica da Expressão Gênica , Masculino , Pré-Escolar , Perfilação da Expressão Gênica/métodos
18.
Neuro Oncol ; 25(7): 1286-1298, 2023 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-36734226

RESUMO

BACKGROUND: A methylation-based classification of ependymoma has recently found broad application. However, the diagnostic advantage and implications for treatment decisions remain unclear. Here, we retrospectively evaluate the impact of surgery and radiotherapy on outcome after molecular reclassification of adult intracranial ependymomas. METHODS: Tumors diagnosed as intracranial ependymomas from 170 adult patients collected from 8 diagnostic institutions were subjected to DNA methylation profiling. Molecular classes, patient characteristics, and treatment were correlated with progression-free survival (PFS). RESULTS: The classifier indicated an ependymal tumor in 73.5%, a different tumor entity in 10.6%, and non-classifiable tumors in 15.9% of cases, respectively. The most prevalent molecular classes were posterior fossa ependymoma group B (EPN-PFB, 32.9%), posterior fossa subependymoma (PF-SE, 25.9%), and supratentorial ZFTA fusion-positive ependymoma (EPN-ZFTA, 11.2%). With a median follow-up of 60.0 months, the 5- and 10-year-PFS rates were 64.5% and 41.8% for EPN-PFB, 67.4% and 45.2% for PF-SE, and 60.3% and 60.3% for EPN-ZFTA. In EPN-PFB, but not in other molecular classes, gross total resection (GTR) (P = .009) and postoperative radiotherapy (P = .007) were significantly associated with improved PFS in multivariable analysis. Histological tumor grading (WHO 2 vs. 3) was not a predictor of the prognosis within molecularly defined ependymoma classes. CONCLUSIONS: DNA methylation profiling improves diagnostic accuracy and risk stratification in adult intracranial ependymoma. The molecular class of PF-SE is unexpectedly prevalent among adult tumors with ependymoma histology and relapsed as frequently as EPN-PFB, despite the supposed benign nature. GTR and radiotherapy may represent key factors in determining the outcome of EPN-PFB patients.


Assuntos
Neoplasias Encefálicas , Ependimoma , Adulto , Humanos , Estudos Retrospectivos , Metilação de DNA , Prognóstico , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/terapia , Ependimoma/diagnóstico , Ependimoma/genética , Ependimoma/terapia
19.
Nat Methods ; 6(12): 883-9, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19898484

RESUMO

To image synaptic activity within neural circuits, we tethered the genetically encoded calcium indicator (GECI) GCaMP2 to synaptic vesicles by fusion to synaptophysin. The resulting reporter, SyGCaMP2, detected the electrical activity of neurons with two advantages over existing cytoplasmic GECIs: it identified the locations of synapses and had a linear response over a wider range of spike frequencies. Simulations and experimental measurements indicated that linearity arises because SyGCaMP2 samples the brief calcium transient passing through the presynaptic compartment close to voltage-sensitive calcium channels rather than changes in bulk calcium concentration. In vivo imaging in zebrafish demonstrated that SyGCaMP2 can assess electrical activity in conventional synapses of spiking neurons in the optic tectum and graded voltage signals transmitted by ribbon synapses of retinal bipolar cells. Localizing a GECI to synaptic terminals provides a strategy for monitoring activity across large groups of neurons at the level of individual synapses.


Assuntos
Cálcio/metabolismo , Sinapses/fisiologia , Potenciais de Ação , Animais , Sinapses/metabolismo , Peixe-Zebra
20.
Acta Neuropathol ; 124(6): 797-807, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22993126

RESUMO

Amyloid-beta plaque deposition represents a major neuropathological hallmark of Alzheimer's disease. While numerous studies have described dendritic spine loss in proximity to plaques, much less is known about the kinetics of these processes. In particular, the question as to whether synapse loss precedes or follows plaque formation remains unanswered. To address this question, and to learn more about the underlying kinetics, we simultaneously imaged amyloid plaque deposition and dendritic spine loss by applying two-photon in vivo microscopy through a cranial window in double transgenic APPPS1 mice. As a result, we first observed that the rate of dendritic spine loss in proximity to plaques is the same in both young and aged animals. However, plaque size only increased significantly in the young cohort, indicating that spine loss persists even many months after initial plaque appearance. Tracking the fate of individual spines revealed that net spine loss is caused by increased spine elimination, with the rate of spine formation remaining constant. Imaging of dendritic spines before and during plaque formation demonstrated that spine loss around plaques commences at least 4 weeks after initial plaque formation. In conclusion, spine loss occurs, shortly but with a significant time delay, after the birth of new plaques, and persists in the vicinity of amyloid plaques over many months. These findings hence give further hope to the possibility that there is a therapeutic window between initial amyloid plaque deposition and the onset of structural damage at spines.


Assuntos
Doença de Alzheimer/patologia , Precursor de Proteína beta-Amiloide/metabolismo , Espinhas Dendríticas/patologia , Placa Amiloide/patologia , Doença de Alzheimer/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Espinhas Dendríticas/metabolismo , Modelos Animais de Doenças , Camundongos , Camundongos Transgênicos , Placa Amiloide/metabolismo , Multimerização Proteica , Sinapses/patologia
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