Racial differences in the pathophysiology of atherothrombosis are poorly understood. We explored the function and transcriptome of platelets in healthy black (n=70) and white (n=84) subjects.
Racial differences in human platelet PAR4 reactivity reflect expression of PCTP and miR-376c.
Specimen part, Race
View SamplesBreast cancer research is hampered by difficulties in obtaining and studying primary human breast tissue, and by the lack of in vivo preclinical models that reflect patient tumor biology accurately. To overcome these limitations, we propagated a cohort of human breast tumors grown in the epithelium-free mammary fat pad of SCID/Beige and NOD/SCID/IL2-receptor null (NSG) mice, under a series of transplant conditions. Both models yielded stably transplantable xenografts at comparably high rates (~23% and ~19%, respectively). Of the conditions tested, xenograft take rate was highest in the presence of a low-dose estradiol pellet. Overall, 32 stably transplantable xenograft lines were established, representing unique 25 patients. Most tumors yielding xenografts were triple-negative (ER-PR-HER2+) (n=19). However, we established lines from three ER-PR-HER2+ tumors, one ER+PR-HER2-, one ER+PR+HER2- and one triple-positive (ER+PR+HER2+) tumor. Serially passaged xenografts show biological consistency with the tumor of origin, are phenotypic stability across multiple transplant generations at the histological, transcriptomic, proteomic, and genomic levels, and show comparable treatment responses. Xenografts representing 12 patients, including two ER+ lines, showed metastasis to the mouse lung. These models thus serve as a renewable, quality-controlled tissue resource for preclinical studies investigating treatment response and metastasis.
A renewable tissue resource of phenotypically stable, biologically and ethnically diverse, patient-derived human breast cancer xenograft models.
Specimen part
View SamplesMecp2 loss-of-function has been associated with altered gene expression in many tissues. We characterized gene expression changes within the hippocampi of 3 different Mecp2 loss-of-function mouse models.
An AT-hook domain in MeCP2 determines the clinical course of Rett syndrome and related disorders.
Age, Specimen part
View SamplesThe molecular mechanism(s) leading to Purkinje neuron loss in the neurodegenerative disorder Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS) are limited by the complex morphology of this cell type. Purkinje neurons are notoriously difficult to isolate and maintain in culture presenting considerable difficultly to identify molecular changes in response to riboCGG repeat-containing mRNA that induces neurotoxicity in FXTAS. Several studies have uncovered a number of RNA binding proteins involved in translation that aberrantly interact with the toxic RNA; however, whether these interactions alter the translational profile of cells has not been investigated. Here we employ bacTRAP translational profiling to demonstrate that Purkinje neurons ectopically expressing 90 CGG repeats exhibit a dramatic change in their translational profile even prior to the onset of riboCGG-induced phenotypes. This approach identified nearly 500 transcripts that are differentially associated with ribosomes in r(CGG)90-expressing mice. Functional annotation cluster analysis revealed broad ontologies enriched in the r(CGG)90 list, including RNA binding and response to stress. Intriguingly, a transcript for the Tardbp gene, implicated in a number of other neurodegenerative disorders, exhibits altered association with ribosomes in the presence of r(CGG)90 repeats. We therefore tested and showed that reduced association of Tardbp mRNA with the ribosomes results in a loss of TDP-43 protein expression in r(CGG)90expressing Purkinje neurons. Furthermore, we showed that TDP-43 could modulate the rCGG repeat-mediated toxicity in a Drosophila model that we developed previously. These findings together suggest translational dysregulation may be an underlying mechanism of riboCGG-induced neurotoxicity and provide insight into the pathogenicity of FXTASBAC-trap studies of Purkinje cels in normal and mutant mice
CGG repeats in RNA modulate expression of TDP-43 in mouse and fly models of fragile X tremor ataxia syndrome.
Age, Specimen part
View SamplesMyc is an oncogenic transcription factor frequently dysregulated in human cancer. To identify pathways supporting the Myc oncogenic program, we employed a genome-wide RNAi screen for Myc-synthetic-lethal (MySL) genes and uncovered a role for the SUMO-activating-enzyme (SAE1/2). Loss of SAE1/2 enzymatic activity drives synthetic lethality with Myc. Mechanistically, SAE2 inhibition switches a transcriptional subprogram of Myc from activated to repressed. A subset of these SUMOylation-dependent Myc-switchers (SMS genes) governs mitotic spindle function and is required to support the Myc oncogenic program.
A SUMOylation-dependent transcriptional subprogram is required for Myc-driven tumorigenesis.
Cell line, Treatment
View SamplesAnalysis of cerebella from Capicua (Cic) mutant mice and wild-type controls at 28 days of age (P28). Spinocerebellar ataxia type 1 (SCA1) is a fatal neurodegenerative disease caused by expansion of a translated CAG repeat in Ataxin-1 (ATXN1). The transcriptional repressor Cic binds directly to Atxn1 and plays a key role in SCA1 pathogenesis. Two isoforms of Cic, long (Cic-L) and short (Cic-S), are transcribed from alternative promoters. Using embryonic stem cells in which the Cic locus was targeted by an insertion of a genetrap cassette between exon 1 of the Cic-L isoform and exon 1 of the Cic-S isoform, we generated mice that carried this allele and backcrossed these onto a Swiss Webster (CD-1) strain for >6 generations. The resulting Cic-L-/- mice completely lack the Cic-L isoform with ~10% of Cic-S remaining. These data were used to compare with previous microarray data to determine the Cic-depedent pathogenic mechanisms in SCA1.
Exercise and genetic rescue of SCA1 via the transcriptional repressor Capicua.
No sample metadata fields
View SamplesWe compared gene expression differences in Atxn1L knockout vs wildtype HSCs
Ataxin1L is a regulator of HSC function highlighting the utility of cross-tissue comparisons for gene discovery.
Specimen part
View Samples