This SuperSeries is composed of the SubSeries listed below.
Transcriptome profile analysis reflects rat liver and kidney damage following chronic ultra-low dose Roundup exposure.
Sex, Specimen part
View SamplesGlyphosate-based herbicides (GBH) are the major pesticides used worldwide. Converging evidence suggests that GBH residues pose a particular risk to the kidneys and liver. However, the existence of biological effects with negative health implications at low environmentally relevant doses remains unresolved. A previous investigation addressed this issue, by conducting a 2-year feeding study, which included 10 female Sprague Dawley rats administered via drinking water with 0.1 ppb of a major Roundup formulation (50 ng/L glyphosate equivalent dilution). Hepatorenal toxicities, as well as urine and blood biochemistry disturbances at the 15th month of age were observed. In an effort to obtain molecular mechanistic insight into the underlying causes of these pathologies, we have carried out a transcriptome microarray analysis of the liver and kidneys from these same animals. The expression of 4224 and 4447 genes were found to be disturbed respectively in liver and kidney (p<0.01, q<0.08, fold change >1.1). Among the 1319 genes whose expression was altered in both tissues, 3 functional categories were over-represented. First, genes involved in mRNA splicing and small nucleolar RNA were mostly upregulated, suggesting disruption of normal spliceosome activity. Electron microscopic analysis of hepatocytes confirmed nucleolar structural disruption. Second, genes controlling chromatin structure (especially histone-lysine N-methyltransferases) were mostly upregulated. Third, genes related to respiratory chain complex I and the tricarboxylic acid cycle were mostly downregulated. The transcription factor networks that can account for these disruptions were centered on CREB1, ESR1, YY1, c-Myc and Oct3/4 activity, which are known to closely cooperate in the regulation of gene expression after hormonal stimulation. The analysis of pathways and toxicity processes showed that these disturbances in gene expression were representative of fibrosis, necrosis, phospholipidosis, mitochondrial membrane dysfunction and ischemia, which correlate with the pathologies observed at an anatomical and histological level. Our results suggest that new studies incorporating testing principles from endocrinology and developmental epigenetics need to be performed to investigate potential consequences of exposure to low dose, environmental levels of GBH and glyphosate.
Transcriptome profile analysis reflects rat liver and kidney damage following chronic ultra-low dose Roundup exposure.
Sex, Specimen part
View SamplesGlyphosate-based herbicides (GBH) are the major pesticides used worldwide. Converging evidence suggests that GBH residues pose a particular risk to the kidneys and liver. However, the existence of biological effects with negative health implications at low environmentally relevant doses remains unresolved. A previous investigation addressed this issue, by conducting a 2-year feeding study, which included 10 female Sprague Dawley rats administered via drinking water with 0.1 ppb of a major Roundup formulation (50 ng/L glyphosate equivalent dilution). Hepatorenal toxicities, as well as urine and blood biochemistry disturbances at the 15th month of age were observed. In an effort to obtain molecular mechanistic insight into the underlying causes of these pathologies, we have carried out a transcriptome microarray analysis of the liver and kidneys from these same animals. The expression of 4224 and 4447 genes were found to be disturbed respectively in liver and kidney (p<0.01, q<0.08, fold change >1.1). Among the 1319 genes whose expression was altered in both tissues, 3 functional categories were over-represented. First, genes involved in mRNA splicing and small nucleolar RNA were mostly upregulated, suggesting disruption of normal spliceosome activity. Electron microscopic analysis of hepatocytes confirmed nucleolar structural disruption. Second, genes controlling chromatin structure (especially histone-lysine N-methyltransferases) were mostly upregulated. Third, genes related to respiratory chain complex I and the tricarboxylic acid cycle were mostly downregulated. The transcription factor networks that can account for these disruptions were centered on CREB1, ESR1, YY1, c-Myc and Oct3/4 activity, which are known to closely cooperate in the regulation of gene expression after hormonal stimulation. The analysis of pathways and toxicity processes showed that these disturbances in gene expression were representative of fibrosis, necrosis, phospholipidosis, mitochondrial membrane dysfunction and ischemia, which correlate with the pathologies observed at an anatomical and histological level. Our results suggest that new studies incorporating testing principles from endocrinology and developmental epigenetics need to be performed to investigate potential consequences of exposure to low dose, environmental levels of GBH and glyphosate.
Transcriptome profile analysis reflects rat liver and kidney damage following chronic ultra-low dose Roundup exposure.
Sex, Specimen part
View SamplesWe analyzed the generation of mouse gliomas following the overexpression of PDGF-B in embryonic neural progenitors. Comparison of our microarray data, with published gene expression data sets for many different murine neural cell types, revealed a closest relationship between our tumor cells and oligodendrocyte progenitor cells, confirming definitively that PDGF-B-induced gliomas are pure oligodendrogliomas.
PDGF-B induces a homogeneous class of oligodendrogliomas from embryonic neural progenitors.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Progression from low- to high-grade in a glioblastoma model reveals the pivotal role of immunoediting.
Specimen part
View SamplesThe different phases of tumor immunoediting in vivo were dissected thanks to a murine model of glioma induced by PDGF-B overexpression. We show that low-grade gliomas are highly immunostimulatory and that the adaptive immune system prevents the development of secondary tumor in syngeneic mice. During tumor progression, glioma cells downregulate immunostimulatory genes and the immune infiltrate becomes pro-tumorigenic. We showed that glioma cells are able to progress towards a high-grade phenotype even in immunodeficient mice, albeit more slowly and this progression invariably requires a downregulation of immunostimulatory genes.
Progression from low- to high-grade in a glioblastoma model reveals the pivotal role of immunoediting.
Specimen part
View SamplesThe different phases of tumor immunoediting in vivo were dissected thanks to a murine model of glioma induced by PDGF-B overexpression. We show that low-grade gliomas are highly immunostimulatory and that the adaptive immune system prevents the development of secondary tumor in syngeneic mice. During tumor progression, glioma cells downregulate immunostimulatory genes and the immune infiltrate becomes pro-tumorigenic.
Progression from low- to high-grade in a glioblastoma model reveals the pivotal role of immunoediting.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Jarid1b targets genes regulating development and is involved in neural differentiation.
Specimen part
View SamplesThe H3K4me2/3 histone demethylase Jarid1b (Kdm5b/Plu1) is dispensable for embryonic stem cell (ESC) self-renewal, but essential for ESC differentiation along the neural lineage. During neural differentiation, Jarid1b depleted ESCs fail to efficiently silence lineage-inappropriate genes, specifically stem and germ cell genes. Our results delineate an essential role for Jarid1b-mediated transcriptional control during ESC differentiation.
Jarid1b targets genes regulating development and is involved in neural differentiation.
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View SamplesEmbryonic development is tightly regulated by transcription factors and chromatin-associated proteins. H3K4me3 is associated with active transcription and H3K27me3 with gene repression, while the combination of both keeps genes required for development in a plastic state. Here we show that deletion of the H3K4me2/3 histone demethylase Jarid1b (Kdm5b/Plu1) results in major neonatal lethality due to respiratory failure. Jarid1b knockout embryos have several neural defects including disorganized cranial nerves, defects in eye development and increased incidences of exencephaly. Moreover, in line with an overlap of Jarid1b and Polycomb targets genes, Jarid1b knockout embryos display homeotic skeletal transformations typical for Polycomb mutants. Genome-wide analysis demonstrated that normally inactive genes encoding developmental regulators acquire aberrant H3K4me3 in early Jarid1b knockout embryos. H3K4me3 accumulates as embryonic development proceeds, leading to increased expression of neural master regulators in knockouts. Taken together, these results suggest that Jarid1b contributes to mouse development by protecting developmental genes from inappropriate acquisition of active histone modifications.
The histone demethylase Jarid1b ensures faithful mouse development by protecting developmental genes from aberrant H3K4me3.
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