Methylazoxymethanol (MAM), the genotoxic metabolite of the cycad azoxyglucoside cycasin, induces genetic alterations in bacteria, yeast, plants, insects and mammalian cells, but adult nerve cells are thought to be unaffected. We show that the brains of young adult mice treated with a single systemic dose of MAM display DNA damage (O6-methylguanine lesions) that peaks at 48 hours and decline to near-normal levels at 7 days post-treatment. By contrast, at this time, MAM-treated mice lacking the gene encoding the DNA repair enzyme O6-methylguanine DNA methyltransferase (MGMT), showed persistent O6-methylguanine DNA damage. The DNA damage was linked to cell-signaling pathways that are perturbed in cancer and neurodegenerative disease. These data are consistent with the established carcinogenic and developmental neurotoxic properties of MAM in rodents, and they support the proposal that cancer and neurodegeneration share common signal transduction pathways. They also strengthen the hypothesis that early life exposure to the MAM glucoside cycasin has an etiological association with a declining, prototypical neurodegenerative disease seen in Guam, Japan, and New Guinea populations that formerly used the neurotoxic cycad plant for medicine and/or food. Exposure to environmental genotoxins may have relevance to the etiology of related tauopathies, notably, Alzheimers disease, as well as cancer.
The cycad genotoxin MAM modulates brain cellular pathways involved in neurodegenerative disease and cancer in a DNA damage-linked manner.
Sex, Specimen part, Time
View SamplesBACKGROUND: The transcript levels of many genes exhibit significant variation in tissue samples from inbred laboratory mice. A microarray experiment was designed to separate transcript abundance variation across samples from adipose, heart, kidney, and liver tissues of C57BL/6J mice into within-mouse and between-mouse components. Within-mouse variance captures variation due to heterogeneity of gene expression within tissues, RNA-extraction, and array processing. Between-mouse variance reflects differences in transcript levels between these genetically identical mice. Many biological sources can contribute to heterogeneous transcript levels within a tissue sample including inherent stochasticity of biochemical processes such as intrinsic and extrinsic noise within cells and differences in cell-type composition which can result from heterogeneity of stem and progenitor cell populations. Differences in global signaling patterns between individuals and micro-environmental influences such as interactions with pathogens and cage mates can also contribute to variation, but are likely to contribute more to the between-mouse variance component.
Stochastic variation of transcript abundance in C57BL/6J mice.
Sex, Age, Specimen part
View SamplesWe have reported previously that when chromosome Y (chrY) from the mouse strain C57BL/6J (abbreviated as B) was substituted for that of A/J mice (ChrY<A>), cardiomyocytes from the resulting 'chromosome substitution' C57BL/6J-chrY<A> strain (abbreviated as B.Y) were smaller than that of their C57BL/6J counterparts. In reverse, when chrY<A> from A/J mice was substituted for that of chrY<B>, cardiomyocytes from the resulting A/J-chrY<C57> strain were larger than in their A/J counterparts. We further used these strains (B and the consomic B.Y) to test whether the origin of chrY could also be linked to differences in the profile of gene expression in their cardiac left ventricles in adult mice where either sham surgery (intact animals) or castration has been performed at 3-4 weeks of age..
Chromosome Y variants from different inbred mouse strains are linked to differences in the morphologic and molecular responses of cardiac cells to postpubertal testosterone.
Sex
View SamplesThe gene expression of bone marrow Hdc-/- and WT (LSK, Lin-c-kit+Sca-1+) hematopoetic stem and progenitor cells were isolated from Hdc-/- or WT mice. Cells were sorted by the cell surface markers of LSK total RNA was isolated from sorted 2,000 HSPCs using the ARCTURUS PicoPure RNA isolation kit (Life Technologies). cDNA was amplified and libraries were constructed by using the SMARTer Ultra Low Input RNA kit (Clontech Laboratories) and the Nextera XT DNA Library Preparation kit (Illumina) according to the respective manufacturer's instructions. Sequencing was performed on the Illumina HiSeq2500 platform. Overall design: a. Hdc-/- bone marrow HSPC (n=4) b. WT bone marrow HSPC (n=4)
Histidine decarboxylase (HDC)-expressing granulocytic myeloid cells induce and recruit Foxp3<sup>+</sup> regulatory T cells in murine colon cancer.
Specimen part, Subject
View SamplesBone marrow Hdc-GFP+/hi and Hdc-GFP-/loCD11b+Gr1+ cells were isolated from bones from histidine decarboxylase (Hdc) green fluorescent protein (Hdc-GFP) mice Hdc-GFP+/hiCD11b+Gr1+ cells and Hdc-GFP-/loCD11b+Gr1+ cells were sorted by combinations of GFP and myeloid cell surface markers CD11b and Gr1 and their differential mRNA expression compared with Affymetrix microarrays.
Histidine decarboxylase (HDC)-expressing granulocytic myeloid cells induce and recruit Foxp3<sup>+</sup> regulatory T cells in murine colon cancer.
Sex, Specimen part
View SamplesGenetic variation governs protein expression through both transcriptional and post-transcriptional processes. To investigate this relationship, we combined a multiplexed, mass spectrometry-based method for protein quantification with an emerging mouse model harboring extensive genetic variation from 8 founder strains. We collected genome-wide mRNA and protein profiling measurements to link genetic variation to protein expression differences in livers from 192 Diversity Outcross mice. Overall design: Illumina 100bp single-end liver RNA-seq from 192 male and female Diversity Outbred 26-week old mice raised on standard chow or high fat diet. Each sample was sequenced in 2x technical replicates across multiple flowcells. Samples were randomly assigned lanes and multiplexed at 12-24x.
Epistatic Networks Jointly Influence Phenotypes Related to Metabolic Disease and Gene Expression in Diversity Outbred Mice.
Sex, Specimen part, Cell line, Subject
View SamplesIdentifying the genes underlying quantitative trait loci (QTL) for disease has proven difficult, mainly due to the low resolution of the approach and the complex genetics involved. However, recent advances in bioinformatics and the availability of genetic resources now make it possible to narrow the genetic intervals and test candidate genes. In addition to identifying the causative genes, defining the pathways that are affected by these QTL is of major importance as it can give us insight into the disease process and provide evidence to support candidate genes. In this study we mapped three significant and one suggestive QTL on Chromosomes (Chrs) 1, 4, 15, and 17, respectively, for increased albumin excretion (measured as albumin-to-creatinine ratio) in a cross between the MRL/MpJ and SM/J mouse inbred strains. By combining data from several sources and by utilizing gene expression data, we identified Tlr12 as a likely candidate for the Chr 4 QTL. Through the mapping of 33,881 transcripts measured by microarray on kidney RNA from each of the 173 male F2 animals, we identified several downstream pathways associated with these QTL. Among these were the glycan degradation, leukocyte migration, and antigen presenting pathways. We demonstrate that by combining data from multiple sources, we can identify not only genes that are likely to be causal candidates for QTL, but also the pathways through which these genes act to alter phenotypes. This combined approach provides valuable insights into the causes and consequences of renal disease.
Uncovering genes and regulatory pathways related to urinary albumin excretion.
Sex, Age
View SamplesAnalysis of tissues of DBA/2 mice fed a standard breeding diet (SBD) and high fat diet (HFD) revealed tissue specific roles in inflammation and disease, and altered communication between tissues. The tissues surveyed incuded adipose tissues (brown, inguinal, mesenteric, retro-peritoneal, subcutaneious and gonadal), muscle and liver.
High-fat diet leads to tissue-specific changes reflecting risk factors for diseases in DBA/2J mice.
Specimen part, Treatment
View SamplesRosiglitazone (Rosi), a member of the thiazolidinedione class of drugs used to treat type 2 diabetes, activates the adipocyte-specific transcription factor peroxisome proliferator-activated receptor gamma (PPARg). This activation causes bone loss in animals and humans, at least in part due to suppression of osteoblast differentiation from marrow mesenchymal stem cells (MSC). In order to identify mechanisms by which PPARg2 suppresses osteoblastogenesis and promotes adipogenesis in MSC, we have analyzed the PPARg2 transcriptome in response to Rosi. A total of 4,252 transcriptional changes resulted when Rosi (1 uM) was applied to the U-33 marrow stromal cell line, stably transfected with PPARg2 (U-33/g2), as compared to non-induced U-33/g2 cells. Differences between U-33/g2 and U-33 cells stably transfected with empty vector (U-33/c) comprised 7,928 transcriptional changes, independent of Rosi. Cell type-, time- and treatment-specific gene clustering uncovered distinct patterns of PPARg2 transcriptional control of MSC lineage commitment. The earliest changes accompanying Rosi activation of PPARg2 included adjustments in morphogenesis, Wnt signaling, and immune responses, as well as sustained induction of lipid metabolism. Expression signatures influenced by longer exposure to Rosi provided evidence for distinct mechanisms governing the repression of osteogenesis and stimulation of adipogenesis. Our results suggest interactions that could lead to the identification of a master regulatory scheme controlling osteoblast differentiation.
PPARgamma2 nuclear receptor controls multiple regulatory pathways of osteoblast differentiation from marrow mesenchymal stem cells.
Compound, Time
View SamplesPharmacological inhibition of cyclooxygenase-2 (COX-2) is being explored as a chemotherapeutic option because COX-2 protein expression is often elevated in many cancers. Cancer cells treated with COX-2 inhibitors, such as the selective COX-2 inhibitor celecoxib, show growth inhibition and the induction of apoptosis, through alterations in inflammatory processes, angiogenesis, cell adhesion and transforming growth factor- signaling. This study was conducted to determine if the same processes are relevant to celecoxibs effects on human colorectal adenocarcinomas treated in vivo. A cohort of 23 patients with primary colorectal adenocarcinomas was randomized to receive a 7-day course of celecoxib (400 mg b.i.d.) or no drug prior to surgical resection. Gene expression profiling was performed on resected adenocarcinomas from patients with and without celecoxib pre-treatment. Using fold change (>1.5) and p-value (<0.05) cut-offs, 190 genes were differentially expressed between adenocarcinomas from patients receiving celecoxib and those that did not. Of the differentially expressed genes, multiple genes involved in cellular lipid and glutathione metabolism showed decreased expression levels in celecoxib pre-treated samples; changes associated with diminished cellular proliferation. Other observed gene expression changes consistent with reduced proliferation include: altered expression of genes involved in cell adhesion (including collagen, laminin, von Willebrand factor and tenascin C), increased expression of inflammatory modulators (including inerleukin-6, S100 calcium binding protein A8, and several chemokines) and decreased expression of the pro-angiogenic gene, angiogenin. Celecoxib pre-treatment for 7 days in vivo is associated with alterations in colorectal adenocarcinoma gene expression which are suggestive of diminished cellular proliferation.
Celecoxib pre-treatment in human colorectal adenocarcinoma patients is associated with gene expression alterations suggestive of diminished cellular proliferation.
Sex, Disease stage, Treatment
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