This SuperSeries is composed of the SubSeries listed below.
A mouse model of the most aggressive subgroup of human medulloblastoma.
Specimen part
View SamplesMouse models of medulloblastoma are compared to human subgroups through microarray expression and other measures
A mouse model of the most aggressive subgroup of human medulloblastoma.
No sample metadata fields
View SamplesGenomic 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 SamplesThis SuperSeries is composed of the SubSeries listed below.
Evolutionary etiology of high-grade astrocytomas.
Sex, Time
View SamplesTo determine the regulatory pathways necessary for astrocytoma formation within complex adult brain microenvironments, we engineered mice for adult astrocyte-specific disruption of key regulators (pRb, Kras and Pten). Drivers of all astrocytoma grades were identified using CreERTM-inducible alleles. Inactivation of pRb was necessary to initiate grade II disease, and was the only lesion to do so. Additional activation of Kras progressed disease to grade III, while further Pten inactivation facilitated grade IV (glioblastoma) progression. These outcomes were elicited whether somatic events were induced broadly or focally. In vivo inactivation of pRb, which induced astrocyte proliferation and apoptosis, activated the MAPK pathway, while Kras activation and Pten loss triggered PI3K pathways.
Evolutionary etiology of high-grade astrocytomas.
Sex, Time
View SamplesDiet-induced obesity (DIO) is rapidly becoming a global health problem, particularly as Westernization of emerging nations continues. Currently, one third of adult Americans are considered obese and, if current trends continue, >90% of US citizens are predicted to be affected by 2050. However, efforts to fight this epidemic have not yet produced sound solutions for prevention or treatment. Our studies reveal a balanced and chronobiological relationship between food consumption, daily variation in gut microbial evenness and function, basomedial hypothalamic circadian clock (CC) gene expression, and key hepatic metabolic regulatory networks , including CC and nuclear receptors (NR), that is are essential for metabolic homeostasis. Western diets high in saturated fats dramatically alter diurnal variation in microbial composition and function, which in turn lead to uncoupling of the hepatic CC and NR networks from central CC control in ways that offset the timing and types of regulatory factors directing metabolic function. These signals include microbial metabolites such as short chain fatty acids (SCFAs) and hydrogen sulfide (H2S) that can directly regulate or disrupt metabolic networks of the hepatocyte. Our study therefore provides insights into the complex and dynamic relationships between diet, gut microbes, and the host that are critical for maintenance of health. Perturbations of this constellation of processes, in this case by diet-induced dysbiosis and its metabolomic signaling, can potentially promote metabolic imbalances and disease. This knowledge opens up many possibilities for novel therapeutic and interventional strategies to treat and prevent DIO, ranging from the manipulation of gut microbial function to pharmacological targeting of host pathways to restore metabolic balance.
Effects of diurnal variation of gut microbes and high-fat feeding on host circadian clock function and metabolism.
Specimen part
View SamplesTranscriptom analysis of stellate sympathetic ganglia after 8 weeks of cardiac pressure overload caused by transverse aortic constriction.
Sympathetic alpha(2)-adrenoceptors prevent cardiac hypertrophy and fibrosis in mice at baseline but not after chronic pressure overload.
Sex
View SamplesInhibition of miR-33 results in increased cholesterol efflux and HDL-cholesterol levels in mice. In this study we examined the effect of miR-33 inhibition in a mouse model of atherosclerosis and observed significant reduction in atherosclerotic plaque size. At the end of the study, gene expression in macrophages from the atherosclerotic plaques was assessed.
Antagonism of miR-33 in mice promotes reverse cholesterol transport and regression of atherosclerosis.
Sex, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Time of feeding and the intrinsic circadian clock drive rhythms in hepatic gene expression.
No sample metadata fields
View SamplesRestricted feeding impacts the hepatic circadian clock of WT mice. Cry1, Cry2 double KO mice lack a circadian clock and are thus expected to show rhythmical gene expression in the liver. Imposing a temporally restricted feeding schedule on these mice shows how the hepatic circadian clock and rhythmic food intake regulate rhythmic transcription in parallel
Time of feeding and the intrinsic circadian clock drive rhythms in hepatic gene expression.
No sample metadata fields
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