Major causes of lipid accumulation in liver are increased import, synthesis or decreased catabolism of fatty acids. The latter is caused by dysfunction of cellular organelle controlling energy homeostasis, i.e. mitochondria. However, peroxisomes appear to be an important organelle in lipid metabolism of hepatocytes, but little is known about their role in the development of non-alcoholic fatty liver disease (NAFLD). To investigate the role of peroxisomes next to mitochondria in excessive hepatic lipid accumulation we used the leptin resistant db/db mice on C57BLKS background, a mouse model that develops hyperphagia induced diabetes with obesity and NAFLD.
Peroxisomes compensate hepatic lipid overflow in mice with fatty liver.
Sex, Age, Specimen part
View SamplesActivation or maintenance of a leukemia stem cell self-renewal pathway in downstream myeloid cells is an important component of AML development
The Wnt/beta-catenin pathway is required for the development of leukemia stem cells in AML.
Specimen part
View SamplesThe first clinical trial testing the combination of targeted therapy with a BRAF inhibitor vemurafenib and immunotherapy with a CTLA-4 antibody ipilimumab was terminated early due to significant liver toxicities, possibly due to paradoxical activation of the MAPK pathway by BRAF inhibitors in tumors with wild type BRAF. MEK inhibitors can potentiate the MAPK inhibition in tumor, while potentially alleviating the unwanted paradoxical MAPK activation. With a mouse model of syngeneic BRAFV600E driven melanoma (SM1), we tested whether the addition of the MEK inhibitor trametinib would enhance the immunosensitization effects of the BRAF inhibitor dabrafenib. Combination of dabrafenib and trametinib with pmel-1 adoptive cell transfer (ACT) showed complete tumor regression. Bioluminescent imaging and tumor infiltrating lymphocyte (TIL) phenotyping showed increased effector infiltration to tumors with dabrafenib, trametinib or dabrafenib plus trametinib with pmel-1 ACT combination. Intracellular IFN gamma staining of the TILs and in vivo cytotoxicity studies showed trametinib was not detrimental to the effector functions in vivo. Dabrafenib increased tumor associated macrophages and T regulatory cells (Tregs) in the tumors, which can be overcome by addition of trametinib. Microarray analysis revealed increased melanoma antigen, MHC expression, and global immune-related gene upregulation with the triple combination therapy. Given the up-regulation of PD-L1 seen with dabrafenib and/or trametinib combined with antigen specific ACT, we tested the triple combination of dabrafenib, trametinib with anti-PD1 therapy, and observed superior anti-tumor effect to SM1 tumors. Our findings support the testing of these combinations in patients with BRAFV600E mutant metastatic melanoma.
Improved antitumor activity of immunotherapy with BRAF and MEK inhibitors in BRAF(V600E) melanoma.
Specimen part, Treatment, Compound
View SamplesMitochondrial defects are associated with a spectrum of human disorders, ranging from rare, inborn errors of metabolism to common, age-associated diseases such as diabetes and neurodegeneration. In lower organisms, genetic retrograde signaling programs have been identified that promote cellular and organism survival in the face of mitochondrial dysfunction. Here, we characterized the transcriptional component of the human mitochondrial retrograde response in an inducible model of mitochondrial dysfunction.
Mitochondrial dysfunction remodels one-carbon metabolism in human cells.
Cell line
View SamplesUremic media calcification is not only driven by systemic factors such as hyperphosphatemia, but also crticially dependent on vascular smooth muscle cells per se. We hypothesized that the different developmental origins of vscular smooth muscle cells might lead to a heterogeneous susceptibility to develop media calcification.
Heterogeneous susceptibility for uraemic media calcification and concomitant inflammation within the arterial tree.
Specimen part
View SamplesThe thorough characterization of the transcriptome of endogenous podocytes has been hampered by low yields of cell isolation procedures. Here we introduce a double fluorescent reporter mouse model combined with an optimized bead perfusion protocol and efficient single cell dissociation yielding more than 500,000 podocytes per mouse allowing for global, unbiased downstream applications. Combining mRNA transcriptional profiling revealed programs of highly specific gene regulation tightly controlling cytoskeleton, cell differentiation, endosomal transport and peroxisome function in podocytes. Strikingly, the analyses further predict that these podocyte-specific gene regulatory networks are accompanied by alternative splicing of respective genes. In summary, the presented omics approach will facilitate the discovery and integration of novel gene, protein and organelle regulatory networks that deepen our systematic understanding of podocyte biology.
Molecular fingerprinting of the podocyte reveals novel gene and protein regulatory networks.
Specimen part
View SamplesSelenium, one of a class of selenocysteine-containing proteins (selenoproteins), is an essential micronutrient known for its cancer prevention properties. Selenoprotein H (SepH) is a recently identified nucleolar oxidoreductase whose function is not well understood. Here we report that seph is an essential gene regulating organ development in zebrafish. Metabolite profiling by targeted LCMS/ MS demonstrated that SepH deficiency impairs redox balance by reducing the levels of ascorbate and methionine, while increasing methionine sulfoxide. Transcriptome analysis revealed that SepH deficiency induces an inflammatory response and activates the p53 pathway. Consequently, loss of seph renders larvae susceptible to oxidative stress and DNA damage. Finally, we demonstrate that seph interacts with p53 deficiency in adulthood to accelerate gastrointestinal tumor development. Overall, our findings establish that seph regulates redox homeostasis and suppresses DNA damage. We hypothesize that SepH deficiency may contribute to the increased cancer risk observed in cohorts with low selenium levels. Overall design: 4 WT zebrafish samples and 4 SepH mutant samples
Selenoprotein H is an essential regulator of redox homeostasis that cooperates with p53 in development and tumorigenesis.
Subject
View SamplesThe modes of triazole reproductive toxicity have been characterized by an observed increased in serum testosterone and reduced insemination and fertility indices. The key events involved in the disruption in testosterone homeostasis and reduced fertility remain unclear. Gene expression analysis was conducted on liver from Sprague Dawley rats dosed with myclobutanil (300 mg/kg/day) or triadimefon (175 mg/kg/day) for 6, 24 or 336 hours. Pathway-based analysis highlighted key biological processes affected by all three triazoles in the liver including fatty acid catabolism, steroid metabolism, and xenobiotic metabolism. Within the pathways identified in the liver, specific genes involved in phase I-III metabolism and fatty acid metabolism were affected by all three triazoles. These modulated genes are part of a network of lipid and testosterone homeostasis pathways regulated by the constitutive androstane (CAR) and pregnane X (PXR) receptors. Gene expression profiles from this study indicate triazoles activate CAR and PXR; increase fatty acid catabolism and steroid metabolism in the liver; constituting a plausible series of key events contributing to the observed disruption in testosterone homeostasis.
Toxicogenomic effects common to triazole antifungals and conserved between rats and humans.
No sample metadata fields
View SamplesThe triazole antifungals myclobutanil (MYC), propiconazole (PPZ) and triadimefon (TDF) [Propiconazole CASNR 60207-90-1; Triadimefon CASNR 43121-43-3; Myclobutanil CASNR 88671-89-0] all disrupt steroid hormone homeostasis and cause varying degrees of hepatic toxicity. To identify biological pathways consistently activated across various study designs, gene expression profiling was conducted on livers from rats following acute, repeated dose, or prenatal to adult exposures. To explore conservation of responses across species, gene expression from these rat in vivo studies were also compared to in vitro data from rat and human primary hepatocytes exposed to MYC, PPZ, or TDF. Pathway and gene level analyses across time of exposure, dose, and species identified patterns of expression common to all three triazoles, which were also conserved between rodents and humans. Pathways affected included androgen and estrogen metabolism, xenobiotic metabolism signaling through CAR and PXR, and CYP mediated metabolism. Many of the differentially expressed genes are regulated by the nuclear receptors CAR, PPAR alpha and PXR, including ABC transporter genes (Abcb1 and MDR1), genes significant to xenobiotic, fatty acid, sterol and steroid metabolism (Cyp2b2 and CYP2B6; Cyp3a1 and CYP3A4; Cyp4a22 and CYP4A11) and xxx (Ugt1a1 and UGT1A1). Modulation of hepatic sterol and steroid metabolism is a plausible mechanism for triazole induced increases in serum testosterone. The gene expression changes caused by all three triazoles appear to focus on pathways regulating lipid and testosterone homeostasis, identifying potential common mechanisms of triazole hepatotoxicity that are conserved between rodents and humans.
Toxicogenomic effects common to triazole antifungals and conserved between rats and humans.
No sample metadata fields
View SamplesThe modes of triazole reproductive toxicity have been characterized by an observed increased in serum testosterone and reduced insemination and fertility indices. The key events involved in the disruption in testosterone homeostasis and reduced fertility remain unclear. Gene expression analysis was conducted on liver and testis from Wistar Han IGS rats fed myclobutanil (M: 500, 2000 ppm), propiconazole (P: 500, 2500 ppm), or triadimefon (T: 500, 1800 ppm) from gestation day six to postnatal day 92. Pathway-based analysis highlighted key biological processes affected by all three triazoles in the liver including fatty acid catabolism, steroid metabolism, and xenobiotic metabolism. Triadimefon induced a distinctive expression profile of genes involved in liver sterol biosynthesis. There were no common pathways modulated by all three triazoles in the testis. Within the pathways identified in the liver, specific genes involved in phase I-III metabolism (Aldh1a1, Cyp1a1, Cyp2b2, Cyp3a1, Slco1a4, Udpgtr2), fatty acid metabolism (Cyp4a10, Pc, Ppap2b), and steroid metabolism (Srd5a1, Ugt1a1, Ugt2a1) were affected by all three triazoles. These modulated genes are part of a network of lipid and testosterone homeostasis pathways regulated by the constitutive androstane (CAR) and pregnane X (PXR) receptors. Gene expression profiles from this study indicate triazoles activate CAR and PXR; increase fatty acid catabolism, sterol biosynthesis, and steroid metabolism in the liver; constituting a plausible series of key events contributing to the observed disruption in testosterone homeostasis.
Mode of action for reproductive and hepatic toxicity inferred from a genomic study of triazole antifungals.
No sample metadata fields
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