Tris(2-chloroethyl) phosphate (TCEP) is a pervasive flame retardant that has been identified as a chemical of concern given its health effects and therefore its use has since been tightly regulated. Tris(2-chloroisopropyl) phosphate (TCIPP), an analogue of TCEP, is believed to be its replacement. However, compared to TCEP, little is known of the toxicological impacts of TCIPP. We used RNA sequencing as unbiased and sensitive tool to identify and compare effects on a transcriptome level of TCEP and TCIPP in the human hepatocellular carcinoma cell line, HepG2. We identified that compared to other flame retardants, TCEP and TCIPP had little cytotoxicity. Treatment with sub-cytotoxic concentrations of the two compounds revealed that both chemicals elicited similar effects; both compounds were found to affect genes involved in immune responses and steroid hormone biosynthesis, while also affecting xenobiotic metabolism pathways in a similar manner. Specifically for effects on immune responses, both compounds were shown to alter the expression of the receptor of the potent and pleiotropic complement component, C5a. Additionally, expression of genes encoding for effector proteins involved in the complement cascade along with other potent inflammatory regulators were found altered in response to TCEP and TCIPP, further emphasizing their potential effects on immune function. Taken together, given that TCIPP elicited similar effects compared to TCEP, and at lower concentrations, the potential health effects of TCIPP need to be further studied for a complete risk assessment of the compound. Overall design: HepG2 cells were treated with low (25 uM) or high (250 uM) concentrations of tris(2-chloroethyl) phosphate (TCEP), low (2.5 uM) or high (25 uM) concentrations of tris(2-chloroisopropyl) phosphate (TCIPP). For control purposes, cells were exposed to 0.1% DMSO alone. Treatment lasted for 72 hours. Treatments were done in triplicate for each condition involving separate cell seeding, cell growth, treatments and RNA extractions per triplicate. RNA was isolated with Trizol (Invitrogen, USA) and RNeasy Kit (Qiagen, GER). Libraries were prepared with the TruSeq Stranded mRNA Sample Preparation Kit (Illumina, USA). 50bp long paired-ends reads were sequenced using the HiSeq(R) 1500 platform (Illumina, USA). Alignment, mapping and annotation of sequenced reads were performed using the CLC Genomics Workbench (CLC Bio, Aarhus, Denmark). Samples were normalized by quantile normalization before being mapped and annotated using the human reference hg19 genome.
A toxicogenomics approach to screen chlorinated flame retardants tris(2-chloroethyl) phosphate and tris(2-chloroisopropyl) phosphate for potential health effects.
Specimen part, Cell line, Treatment, Subject
View SamplesTris (2-butoxyethyl) phosphate (TBOEP) is a compound produced at high volume that is used as both a flame retardant and a plasticizer. It is persistent and bioaccumulative, yet little is known of its toxicological modes of action. Such insight may aid risk assessment in a weight-of-evidence approach supplementing current testing strategies. We used an RNA sequencing approach as an unbiased and sensitive tool to explore potential negative health effects of sub-cytotoxic concentrations of TBOEP on the transcriptome of the human liver hepatocellular carcinoma cell line, HepG2, with the lowest concentration used potentially holding relevance to human physiological levels. Over-representation and gene set enrichment analysis corresponded well and revealed that TBOEP treatments resulted in an upregulation of genes involved in protein and energy metabolism, along with DNA replication. Such increases in cell and macromolecule metabolism could explain the increase in mitochondrial activity at lower TBOEP concentrations. In addition, TBOEP affected a wide variety of biological processes, the most notable one being the general stress response, wound healing. Finally, TBOEP showed effects on steroid hormone biosynthesis and activation, regulation, and potentiation of immune responses, in agreement with other studies. As such, this study is the first study investigating genome-wide changes in gene transcription in response to TBOEP in human cells. Overall design: HepG2 cells were treated with low (2.5 uM) or high (125 uM) concentrations of Tris (2-butoxyethyl) phosphate (TBOEP) in 0.1% DMSO. For control purposes cells were exposed to 0.1% DMSO alone. Treatment lasted for 72 hours. All treatments were conducted in triplicates, involving separate seeding of cells. RNA was isolated with Trizol (Invitrogen, USA) and RNeasy Kit (Qiagen, GER). Libraries were prepared with the TruSeq Stranded mRNA Sample Preparation Kit (Illumina, USA). 50bp long paired-ends reads were sequenced using the HiSeq(R) 1500 platform (Illumina, USA). Alignement to the UCSC hg19 assembly of the human genome, mapping and annotation was performed with CLC Genomics Workbench (CLC Bio, DEN). Samples were normalised by quantile normalisation. Differential expression p-values were generated using Baggerly''s test statistic. These p-values were subsequently corrected with the Benjamini-Hochberg procedure to limit the false discovery rate (FDR) to 5% of the significant genes .
Toxicogenomics of the flame retardant tris (2-butoxyethyl) phosphate in HepG2 cells using RNA-seq.
Cell line, Treatment, Subject
View SamplesThe transcription factor NF-E2-related factor 2 (Nrf2) induces cytoprotective genes, but has also been linked to the regulation of hepatic energy metabolism. In order to assess the pharmacological potential of hepatic Nrf2 activation in metabolic disease, Nrf2 was activated over 8 weeks in mice on Western diet using two different siRNAs against kelch-like ECH-associated protein 1 (Keap1), the inhibitory protein of Nrf2. Whole genome expression analysis followed by pathway analysis demonstrated that the suppression of Keap1 expression induced genes that are involved in anti-oxidative stress defense and biotransformation, pathways proving the activation of Nrf2 by the siRNAs against Keap1. The expression of neither fatty acid- nor carbohydrate-handling proteins was regulated by the suppression of Keap1. Metabolic profiling of the animals did also not show effects on plasma and hepatic lipids, energy expenditure or glucose tolerance by the activation of Nrf2. The data indicate that hepatic Nrf2 is not a major regulator of intermediary metabolism in mice.
Chronic Activation of Hepatic Nrf2 Has No Major Effect on Fatty Acid and Glucose Metabolism in Adult Mice.
Specimen part, Treatment
View SamplesSTING molecule has been reported to be important adaptor molecule for cytosolic DNA sensing. We investigated gene expression by cytosolic DNA stimulation using bone marrow derived dendritic cells. We comparared gene expression profile between WT and STING knock out BMDCs after cytosolic DNA stimulation.
STING-dependent cytosolic DNA sensing mediates innate immune recognition of immunogenic tumors.
Specimen part
View SamplesOrganoid technology provides the possibility to culture human colon tissue and patient-derived colorectal cancers (CRC) while maintaining all functional and phenotypic characteristics. Labeling of human colon stem cells (CoSCs), especially in normal and benign tumor organoids, is challenging and therefore limits usability of multi-patient organoid libraries for CoSC research. Here, we developed STAR (STem cell Ascl2 Reporter), a minimal enhancer/promoter element that reports transcriptional activity of ASCL2, a master regulator of LGR5+ CoSC fate. Among others via lentiviral infection, STAR minigene labels stem cells in normal as well as in multiple engineered and patient-derived CRC organoids of different stage and genetic make-up. STAR revealed that stem cell driven differentiation hierarchies and the capacity of cell fate plasticity (de-differentiation) are present at all stages of human CRC development. The flexible and user-friendly nature of STAR applications in combination with organoid technology will facilitate basic research on human adult stem cell biology. Overall design: Cells from different colon organoid types were FACS sorted for stem STemness Ascl2 Reporter activity for transcriptome profiling by RNA-seq.
Specific Labeling of Stem Cell Activity in Human Colorectal Organoids Using an ASCL2-Responsive Minigene.
Subject
View SamplesIn the present study, we investigated the importance of histone deacetylase 6 (HDAC6) for glucocorticoid receptor (GR) mediated effects on glucose metabolism, and its potential as a therapeutic target for the prevention of glucocorticoid (GC)-induced diabetes. Dexamethasone (dex)-induced hepatic glucose output and GR translocation were analysed in wildtype (wt) and HDAC6-deficient (HDAC6ko) mice. The effect of the specific HDAC6-inhibitor tubacin was analysed in-vitro. Wt and HDAC6ko mice were subjected to 3 weeks dex treatment before analysis of glucose and insulin tolerance. HDAC6ko mice showed impaired dex-induced hepatic GR translocation. Accordingly, dex induced expression of a large number of hepatic genes was significantly attenuated in mice lacking HDAC6 and by tubacin in-vitro. Glucose output of primary hepatocytes from HDAC6ko mice was diminished. A significant improvement of dex-induced whole-body glucose intolerance as well as insulin resistance in HDAC6ko mice compared to wt littermates was observed. The present study demonstrates that HDAC6 is an essential regulator of hepatic GC stimulated gluconeogenesis and impairment of whole body glucose metabolism through modification of GR nuclear translocation. Selective pharmacological inhibition of HDAC6 may provide a future therapeutic option against the pro-diabetogenic actions of GCs.
Histone deacetylase 6 (HDAC6) is an essential modifier of glucocorticoid-induced hepatic gluconeogenesis.
Sex, Specimen part, Treatment
View SamplesObjectives: Systemic inflammation is a major risk factor for critical-illness myopathy (CIM) but its pathogenic role in muscle is uncertain. We observed that interleukin 6 (IL-6) and serum amyloid A1 (SAA1) expression was upregulated in muscle of critically ill patients. To test the relevance of these responses we assessed inflammation and acute-phase response at early and late time points in muscle of patients at risk for CIM.
Inflammation-induced acute phase response in skeletal muscle and critical illness myopathy.
Sex, Age, Specimen part, Disease, Subject
View SamplesLiver injury results in rapid regeneration through hepatocyte proliferation and hypertrophy. However, after acute severe injury, such as acetaminophen poisoning, effective regeneration may fail. We investigated how senescence underlies this regenerative failure. In human acute liver disease, and murine models, p21-dependent hepatocellular senescence was proportionate to disease severity and was associated with impaired regeneration. In an acetaminophen injury model a transcriptional signature associated with the induction of paracrine senescence is observed within twenty four hours, and is followed by one of impaired proliferation. In genetic models of hepatocyte injury and senescence we observed transmission of senescence to local uninjured hepatocytes. Spread of senescence depended upon macrophage derived TGFß1 ligand. In acetaminophen poisoning inhibition of TGFß receptor 1 (TGFßR1) improved survival. TGFßR1 inhibition reduced senescence and enhanced liver regeneration even when delivered after the current therapeutic window. This mechanism, in which injury induced senescence impairs regeneration, is an attractive therapeutic target for acute liver failure. Overall design: RNA-seq analysis was performed on a total of 24 samples extracted from murine liver, post hepatic injury induced by acetaminophen administration. Transcriptional profiles were from replicate samples generated at defined timepoints - 12, 24, 36, 48 and 72 hours post injury. Replicate samples were generated from 4 individual animals sacrificed at each timepoint, and compared to a control cohort of 4 animals not subjected to acetaminophen treatment.
TGFβ inhibition restores a regenerative response in acute liver injury by suppressing paracrine senescence.
Specimen part, Cell line, Subject, Time
View SamplesSchimke immuno-osseous dysplasia (SIOD) is a multisystemic disorder caused by biallelic mutations in SWI/SNF-related matrix associated actin-dependent regulator of chromatin, subfamily A-like protein 1 (SMARCAL1). Changes in gene expression appear to underlie the immunodeficiency and arteriosclerosis of SIOD; therefore, we hypothesized that SMARCAL1 deficiency alters renal gene expression to cause the focal segmental glomerulosclerosis (FSGS) of SIOD, and that these gene expression alterations would be comparable to those observed in isolated FSGS. We tested this hypothesis by gene expression microarray analysis.
Increased Wnt and Notch signaling: a clue to the renal disease in Schimke immuno-osseous dysplasia?
Sex
View SamplesSchimke immuno-osseous dysplasia (SIOD) is a multisystemic disorder caused by biallelic mutations in SWI/SNF-related matrix associated actin-dependent regulator of chromatin, subfamily A-like protein 1 (SMARCAL1). Changes in gene expression appear to underlie the immunodeficiency and arteriosclerosis of SIOD; therefore, we hypothesized that SMARCAL1 deficiency alters renal gene expression to cause the focal segmental glomerulosclerosis (FSGS) of SIOD. We tested this hypothesis by transcriptome analysis and quantitative reverse transcription PCR (qRT-PCR) of an SIOD patient kidney, a genetic screen and immunofluorescence. These showed increased expression of genes in the Wnt and Notch signaling pathways in an SIOD patient kidney, interaction of Marcal1 with genes encoding components of the Wnt and Notch signaling pathways, and increased levels of unphosphorylated b-catenin and Notch1 intracellular domain (NICD) in the glomeruli of SIOD patient kidneys. Given that increased Wnt and Notch activity are established causes of FSGS, we hypothesize that SMARCAL1 deficiency increases the activity of one or both of these pathways to cause the renal disease of most SIOD patients. Overall design: Comparison of mRNA levels between the kidney tissue of a Schimke immuno-osseous dysplasia (SIOD) patient and an unaffected control
Increased Wnt and Notch signaling: a clue to the renal disease in Schimke immuno-osseous dysplasia?
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