Genomic technologies have unmasked molecularly distinct subgroups among tumors of the same histological type; but understanding the biologic basis of these subgroups has proved difficult since their defining alterations are often numerous, and the cellular origins of most cancers remain unknown. We sought to decipher complex genomic data sets by matching the genetic alterations contained within these, with candidate cells of origin, to generate accurate disease models. Using an integrated genomic analysis we first identified subgroups of human ependymoma: a form of neural tumor that arises throughout the central nervous system (CNS). Validated alterations included amplifications and homozygous deletions of genes not yet implicated in ependymoma. Matching the transcriptomes of human ependymoma subgroups to those of distinct types of mouse radial glia (RG)neural stem cells (NSCs) that we identified previously to be a candidate cell of origin of ependymoma - allowed us to select RG types most likely to represent cells of origin of disease subgroups. The transcriptome of human cerebral ependymomas that amplify EPHB2 and delete INK4A/ARF matched most closely that of embryonic cerebral Ink4a/Arf-/- RG: remarkably, activation of EphB2 signaling in this RG type, but not others, generated highly penetrant ependymomas that modeled accurately the histology and transcriptome of one human cerebral tumor subgroup (subgroup D). Further comparative genomic analysis revealed selective alterations in the copy number and expression of genes that regulate neural differentiation, particularly synaptogenesis, in both mouse and human subgroup D ependymomas; pinpointing this pathway as a previously unknown target of ependymoma tumorigenesis. Our data demonstrate the power of comparative genomics to sift complex genetic data sets to identify key molecular alterations in cancer subgroups.
Cross-species genomics matches driver mutations and cell compartments to model ependymoma.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesMedulloblastoma encompasses a collection of clinically and molecularly diverse tumor subtypes that together comprise the most common malignant childhood brain tumor. These tumors are thought to arise within the cerebellum, with approximately 25% originating from granule neuron precursor cells (GNPCs) following aberrant activation of the Sonic Hedgehog pathway (hereafter, SHH-subtype). The pathological processes that drive heterogeneity among the other medulloblastoma subtypes are not known, hindering the development of much needed new therapies. Here, we provide evidence that a discrete subtype of medulloblastoma that contains activating mutations in the WNT pathway effector CTNNB1 (hereafter, WNT-subtype), arises outside the cerebellum from cells of the dorsal brainstem. We found that genes marking human WNT-subtype medulloblastomas are more frequently expressed in the lower rhombic lip (LRL) and embryonic dorsal brainstem than in the upper rhombic lip (URL) and developing cerebellum. Magnetic resonance imaging (MRI) and intra-operative reports showed that human WNT-subtype tumors infiltrate the dorsal brainstem, while SHH-subtype tumors are located within the cerebellar hemispheres. Activating mutations in Ctnnb1 had little impact on progenitor cell populations in the cerebellum, but caused the abnormal accumulation of cells on the embryonic dorsal brainstem that included aberrantly proliferating Zic1+ precursor cells. These lesions persisted in all mutant adult mice and in 15% of cases in which Tp53 was concurrently deleted, progressed to form medulloblastomas that recapitulated the anatomy and gene expression profiles of human WNT-subtype medulloblastoma. We provide the first evidence that subtypes of medulloblastoma have distinct cellular origins. Our data provide an explanation for the marked molecular and clinical differences between SHH and WNT-subtype medulloblastomas and have profound implications for future research and treatment of this important childhood cancer.
Subtypes of medulloblastoma have distinct developmental origins.
Specimen part
View SamplesMedulloblastoma is a malignant childhood brain tumour comprising four discrete subgroups. To identify mutations that drive medulloblastoma we sequenced the entire genomes of 37 tumours and matched normal blood. One hundred and thirty-six genes harbouring somatic mutations in this discovery set were sequenced in an additional 56 medulloblastomas. Recurrent mutations were detected in 41 genes not yet implicated in medulloblastoma: several target distinct components of the epigenetic machinery in different disease subgroups, e.g., regulators of H3K27 and H3K4 trimethylation in subgroup-3 and 4 (e.g., KDM6A and ZMYM3), and CTNNB1-associated chromatin remodellers in WNT-subgroup tumours (e.g., SMARCA4 and CREBBP). Modelling of mutations in mouse lower rhombic lip progenitors that generate WNT-subgroup tumours, identified genes that maintain this cell lineage (DDX3X) as well as mutated genes that initiate (CDH1) or cooperate (PIK3CA) in tumourigenesis. These data provide important new insights into the pathogenesis of medulloblastoma subgroups and highlight targets for therapeutic development.
Novel mutations target distinct subgroups of medulloblastoma.
Sex
View SamplesProteinases play a pivotal role in wound healing by degrading molecular barriers, regulating cell-matrix interactions and availability of bioactive molecules. Matrix metalloproteinase-13 (MMP-13, collagenase-3) is a wide spectrum proteinase. Its expression and function is linked to the growth and invasion of many epithelial cancers such as squamous cell carcinoma. Moreover, the physiologic expression of MMP-13 is associated e.g. to scarless healing of human fetal skin and adult gingival wounds. While MMP-13 is not found in the normally healing skin wounds in human adults, it is expressed in mouse skin during wound healing. Thus, mouse wound healing models can be utilized for studying the role of MMP-13 in the events of wound healing. As the processes such as the migration and proliferation of keratinocytes, angiogenesis, inflammation and activation of fibroblasts are components of wound repair as well as of cancer, many results received from wound healing studies are also adaptable to cancer research.
MMP-13 regulates growth of wound granulation tissue and modulates gene expression signatures involved in inflammation, proteolysis, and cell viability.
Time
View SamplesVitamin D is an important calcium-regulating hormone with diverse functions in numerous tissues including the brain. Increasing evidence suggests that vitamin D may play a role in maintaining cognitive function and that vitamin D deficiency may accelerate age-related cognitive decline. Using aging rodents, we attempted to model the range of human serum vitamin D levels, from deficient to sufficient, to test whether vitamin D could preserve or improve cognitive function with aging. For 5-6 months, middle-aged F344 rats were fed diets containing low, medium (typical amount) or high vitamin D3 (100, 1000 or 10,000 IU/kg diet, respectively) and then hippocampal-dependent learning and memory were tested in the Morris water maze. Rats on high vitamin D achieved the highest blood levels (in the sufficient range) and significantly outperformed low and medium groups on maze reversal, a particularly challenging task that detects more subtle changes in memory. In addition to calcium-related processes, hippocampal gene expression microarrays identified pathways pertaining to synaptic transmission, cell communication and G-protein function as being up-regulated with high vitamin D. Basal synaptic transmission also was enhanced corroborating observed effects on gene expression and learning and memory. Our studies demonstrate a causal relationship between vitamin D status and cognitive function and suggest that vitamin D-mediated changes in hippocampal gene expression may improve the likelihood of successful brain aging.
Vitamin D prevents cognitive decline and enhances hippocampal synaptic function in aging rats.
Sex, Specimen part
View SamplesSleep deprivation (SD) in young adults is associated with metabolic, stress and cognitive responses that are also characteristic of brain aging. Given that sleep architecture changes with age, including increased fragmentation and decreased slow wave activity, it seems reasonable to investigate potential molecular relationships between SD and aging in brain tissue. Here, we tested the hypothesis that young rats exposed to 24 or 72 hour SD would respond with stress and aging-like shifts in brain hippocampal CA1 gene expression. SD animals showed blood corticosterone and weight changes consistent with a stress response. Microarray results, validated by Western blot and comparison to prior SD studies, pointed to disruptions in neurotransmission, sleep pressure signaling, and macromolecular synthesis. In a separate experiment, animals exposed to 24 or 72 hour novel environment stress recapitulated nearly one third of the SD transcriptional profile, particularly upregulated apoptotic and immune signaling pathways. Compared to aging (based on three previously published independent hippocampal aging studies), SD transcriptional profiles agreed for neurogenesis and energy pathways. However, immune signaling, glial activity, macromolecular synthesis and neuronal function all showed an SD profile that was, at least in part, opposed by aging. We conclude that while stress and SD have discrete molecular signatures, they do show a subset of highly similar changes. However, the same could not be said of aging and SD, where a similar subset of genes is changed, but in partially divergent directions. Finally, this work identifies presynaptic vesicular release and intercellular adhesion molecular signatures as novel targets for future SD-countering therapeutics.
Hippocampal CA1 transcriptional profile of sleep deprivation: relation to aging and stress.
Sex, Treatment
View SamplesCohesinopathies are characterized by mutations in the cohesin complex. Mutations in NIPBL, a cohesin loader, result in Cornelia de Lange syndrome (CdLS). CdLS is a congenital genetic disorder distinguished by craniofacial dysmorphism, abnormal upper limb development, delayed growth, severe cognitive retardation, and multiple organ malformations.It has been suggested that CdLS is caused by defects in the cohesin network that alter gene expression and genome organization. However, the precise molecular etiology of CdLS is largely unclear. To gain insights, we sequenced mRNAs isolated from mouse embryonic fibroblasts of both WT and NIPBL-haploinsufficient mice and compared their transcriptomes. Overall design: Examination of gene expression of WT and NIPBL+/- mice by RNA-seq
NIPBL Controls RNA Biogenesis to Prevent Activation of the Stress Kinase PKR.
No sample metadata fields
View SamplesDiesel exhaust (DE) has been shown to enhance allergic sensitization in animals following high dose instillation or chronic inhalation exposure scenarios. The purpose of this study was to determine if short term exposures to diluted DE enhance allergic immune responses to antigen, and identify possible mechanisms using microarray technology. BALB/c mice were exposed to filtered air or diluted DE to yield particle concentrations of 500 or 2000 g/m3 4 hr/day on days 0-4. Mice were sensitized intranasally with ovalbumin (OVA) antigen or saline on days 0-2, and 18 and all were challenged with OVA on day 28. Mice were necropsied either 4 hrs after the last DE exposure on day 4, or 18, 48, and 96 hrs after challenge. Immunological endpoints included OVA-specific serum IgE, biochemical and cellular profiles of bronchoalveolar lavage (BAL), and cytokine production in the BAL. OVA-sensitized mice exposed to both concentrations of DE had increased eosinophils, neutrophils, lymphocytes, and IL-6 post-challenge compared to OVA control, while DE/saline exposure yielded increases in neutrophils at the high dose only. Microarray analysis demonstrated distinct gene expression profiles for the high dose DE/OVA and DE/saline groups. DE/OVA induced pathways involved in oxidative stress and metabolism while DE in the absence of allergen sensitization modulated cell cycle control, growth and differentiation, G-proteins, and cell adhesion pathways. This study shows for the first time early changes in gene expression induced by the combination of diesel exhaust inhalation and antigen sensitization, which resulted in stronger development of an allergic asthma phenotype.
Increased transcription of immune and metabolic pathways in naive and allergic mice exposed to diesel exhaust.
No sample metadata fields
View SamplesMaternal smoking doubles the risk of delivering a low birth weight infant. The purpose of this study was to analyze differential gene expression in umbilical cord tissue as a function of maternal smoking, with an emphasis on growth-related genes. We recruited 15 pregnant smokers and 15 women who never smoked during pregnancy to participate RNA was isolated from umbilical cord tissue collected and snap frozen at the time of delivery. Microarray analysis was performed using the Affymetrix GeneChip Scanner 3000.Six hundred seventy-eight probes corresponding to 545 genes were differentially expressed (i.e., an intensity ratio that exceeded +/-1.3 and a corrected significance value p < 0.005) in tissue obtained from smokers versus nonsmokers. Genes important for fetal growth, angiogenesis, or development of connective tissue matrix were up-regulated among smokers. The most highly up-regulated gene was CSH1, a somatomammotropin gene. Two other somatomammotropin genes (CSH2 and CSH-L1) were also up-regulated. The most highly down-regulated gene was APOBEC3A; other down-regulated genes included those that may be important in immune and barrier protection. PCR validation of the three somatomammotropin genes showed a high correlation between qPCR and microarray expression. Consequently, maternal smoking may be associated with altered gene expression in the offspring.
Effects of prenatal tobacco exposure on gene expression profiling in umbilical cord tissue.
No sample metadata fields
View SamplesHuman ILCs are classically categorized into five subsets; cytotoxic CD127-CD94+ NK cells and non-cytotoxic CD127+CD94-, ILC1s, ILC2s, ILC3s and LTi cells. Here, we identify a novel subset within the CD127+ ILC population, characterized by the expression of the cytotoxic marker CD94. These CD94+ ILCs strongly resemble conventional ILC3s in terms of phenotype, transcriptome and cytokine production, but are highly cytotoxic. IL-15 was unable to induce differentiation of CD94+ ILCs towards mature NK cells. Instead, CD94+ ILCs retained RORγt, CD127 and CD200R expression and produced IL-22 in response to IL-15. Culturing non-cytotoxic CD127+ ILC1s or ILC3s with IL-12 induced upregulation of CD94 and cytotoxic activity, effects that were not observed with IL-15 stimulation. Thus, human helper ILCs can acquire a cytotoxic program without differentiating into NK cells.
Identification of human cytotoxic ILC3s.
Specimen part, Subject
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