This SuperSeries is composed of the SubSeries listed below.
Drug-induced endoplasmic reticulum and oxidative stress responses independently sensitize toward TNFα-mediated hepatotoxicity.
Sex, Age, Specimen part, Cell line, Treatment, Subject
View SamplesDrug-induced liver injury (DILI) is an important clinical problem. Here we used a genomics approach to establish the critical drug-induced toxicity pathways that act in synergy with the pro-inflammatory cytokine tumor necrosis factor (TNF) to cause cell death of liver HepG2 cells. Transcriptomics of the cell injury stress response pathways initiated by two hepatoxicants, diclofenac and carbamazepine, revealed the endoplasmic reticulum (ER) stress/translational initiation signaling and Nrf2 antioxidant signaling as two major affected pathways, which was similar to that observed for the majority of ~80 DILI compounds in primary human hepatocytes. The ER stress was primarily related to PERK and ATF4 activation and subsequent expression of CHOP, which was all independent of TNF signaling. Identical ATF4 dependent transcriptional programs were observed in primary human hepatocytes as well as primary precision cut human liver slices. Targeted RNA interference studies revealed that while ER stress signaling through IRE1 and ATF6 acted cytoprotective, activation of the ER stress protein kinase PERK and subsequent expression of CHOP was pivotal for the onset of drug/TNF-induced apoptosis. While inhibition of the Nrf2-dependent adaptive oxidative stress response enhanced the drug/TNF cytotoxicity, Nrf2 signaling did not affect CHOP expression. Both hepatotoxic drugs enhanced expression of the translational initiation factor EIF4A1, which was essential for CHOP expression and drug/TNF-mediated cell killing. Our data support a model in which enhanced drug-induced translation initiates PERK-mediated CHOP signaling in an EIF4A1 dependent manner, thereby sensitizing towards caspase-8-dependent TNF induced apoptosis.
Drug-induced endoplasmic reticulum and oxidative stress responses independently sensitize toward TNFα-mediated hepatotoxicity.
Cell line, Treatment
View SamplesDrug-induced liver injury (DILI) is an important clinical problem. Here we used a genomics approach to establish the critical drug-induced toxicity pathways that act in synergy with the pro-inflammatory cytokine tumor necrosis factor (TNF) to cause cell death of liver HepG2 cells. Transcriptomics of the cell injury stress response pathways initiated by two hepatoxicants, diclofenac and carbamazepine, revealed the endoplasmic reticulum (ER) stress/translational initiation signaling and Nrf2 antioxidant signaling as two major affected pathways, which was similar to that observed for the majority of ~80 DILI compounds in primary human hepatocytes. The ER stress was primarily related to PERK and ATF4 activation and subsequent expression of CHOP, which was all independent of TNF signaling. Identical ATF4 dependent transcriptional programs were observed in primary human hepatocytes as well as primary precision cut human liver slices. Targeted RNA interference studies revealed that while ER stress signaling through IRE1 and ATF6 acted cytoprotective, activation of the ER stress protein kinase PERK and subsequent expression of CHOP was pivotal for the onset of drug/TNF-induced apoptosis. While inhibition of the Nrf2-dependent adaptive oxidative stress response enhanced the drug/TNF cytotoxicity, Nrf2 signaling did not affect CHOP expression. Both hepatotoxic drugs enhanced expression of the translational initiation factor EIF4A1, which was essential for CHOP expression and drug/TNF-mediated cell killing. Our data support a model in which enhanced drug-induced translation initiates PERK-mediated CHOP signaling in an EIF4A1 dependent manner, thereby sensitizing towards caspase-8-dependent TNF induced apoptosis.
Drug-induced endoplasmic reticulum and oxidative stress responses independently sensitize toward TNFα-mediated hepatotoxicity.
Sex, Age, Specimen part, Treatment
View SamplesDrug-induced liver injury (DILI) is an important clinical problem. Here we used a genomics approach to establish the critical drug-induced toxicity pathways that act in synergy with the pro-inflammatory cytokine tumor necrosis factor (TNF) to cause cell death of liver HepG2 cells. Transcriptomics of the cell injury stress response pathways initiated by two hepatoxicants, diclofenac and carbamazepine, revealed the endoplasmic reticulum (ER) stress/translational initiation signaling and Nrf2 antioxidant signaling as two major affected pathways, which was similar to that observed for the majority of ~80 DILI compounds in primary human hepatocytes. The ER stress was primarily related to PERK and ATF4 activation and subsequent expression of CHOP, which was all independent of TNF signaling. Identical ATF4 dependent transcriptional programs were observed in primary human hepatocytes as well as primary precision cut human liver slices. Targeted RNA interference studies revealed that while ER stress signaling through IRE1 and ATF6 acted cytoprotective, activation of the ER stress protein kinase PERK and subsequent expression of CHOP was pivotal for the onset of drug/TNF-induced apoptosis. While inhibition of the Nrf2-dependent adaptive oxidative stress response enhanced the drug/TNF cytotoxicity, Nrf2 signaling did not affect CHOP expression. Both hepatotoxic drugs enhanced expression of the translational initiation factor EIF4A1, which was essential for CHOP expression and drug/TNF-mediated cell killing. Our data support a model in which enhanced drug-induced translation initiates PERK-mediated CHOP signaling in an EIF4A1 dependent manner, thereby sensitizing towards caspase-8-dependent TNF induced apoptosis.
Drug-induced endoplasmic reticulum and oxidative stress responses independently sensitize toward TNFα-mediated hepatotoxicity.
Specimen part, Treatment, Subject
View SamplesRed meat consumption is associated with an increased colon cancer risk. Heme, present in red meat, injures the colon surface epithelium by luminal cytotoxicity and reactive oxygen species. This surface injury is overcompensated by hyperproliferation and hyperplasia of crypt cells. Transcriptome analysis of mucosa of heme-fed mice showed, besides stress- and proliferation-related genes, many upregulated lipid metabolism-related PPAR target genes. The aim of this study was to investigate the role of PPAR in heme-induced hyperproliferation and hyperplasia. Male PPAR KO and WT mice received a purified diet with or without heme. As PPAR is proposed to protect against oxidative stress and lipid peroxidation, we hypothesized that the absence of PPAR leads to more surface injury and crypt hyperproliferation in the colon upon heme-feeding. Heme induced luminal cytotoxicity and lipid peroxidation and colonic hyperproliferation and hyperplasia to the same extent in WT and KO mice. Transcriptome analysis of colonic mucosa confirmed similar heme-induced hyperproliferation in WT and KO mice. Stainings for alkaline phosphatase activity and expression levels of Vanin-1 and Nrf2-targets indicated a compromised antioxidant defense in heme-fed KO mice. Our results suggest that the protective role of PPAR in antioxidant defense involves the Nrf2-inhibitor Fosl1, which is upregulated by heme in PPAR KO mice. We conclude that PPAR plays a protective role in colon against oxidative stress, but PPAR does not mediate heme-induced hyperproliferation. This implies that oxidative stress of surface cells is not the main determinant of heme-induced hyperproliferation and hyperplasia.
Dietary heme-mediated PPARα activation does not affect the heme-induced epithelial hyperproliferation and hyperplasia in mouse colon.
Sex, Specimen part
View SamplesBy conditionally deleting BRD4 at various stages of thymic differentiation, we have established that BRD4 deficiency selectively affects a unique developmental subpopulation of thymocytes. Overall design: We examined by RNA-seq the effect on gene expression of BRD4 deletion in ex vivo DN, ISP, DP, CD4 and CD8 thymocyte subpopulations. The analysis was also performed on WT or BRD4 deleted ISP and DP thymocytes cultured for 16 hours at 37oC In this analysis, the conditional deletion of BRD4 (cKO) is achieved using the LCK-cre Transgene.
Immature CD8 Single-Positive Thymocytes Are a Molecularly Distinct Subpopulation, Selectively Dependent on BRD4 for Their Differentiation.
Specimen part, Treatment, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Dietary haem stimulates epithelial cell turnover by downregulating feedback inhibitors of proliferation in murine colon.
Sex, Age, Specimen part, Treatment
View SamplesThe risk for colon cancer is associated with nutrition, especially high fat and low calcium diets high in red meat. Red meat contains the iron porphyrin pigment heme, which induces cytotoxicity of the colon contents and epithelial hyperproliferation. Using a mouse model, we showed that heme caused damage to the colonic surface epithelium and induced compensatory hyperproliferation. Expression levels of heme- and stress-related genes show that heme affects surface cells and not directly crypt cells. Therefore, injured surface cells should signal to crypt TA cells to induce compensatory hyperproliferation. Surface-specific downregulated inhibitors of proliferation were Wnt inhibitory factor 1, Indian Hedgehog, Bone morphogenic protein 2 and possibly Interleukin-15. Heme also upregulated Amphiregulin, Epiregulin and Cyclooxygenase-2 mRNA in the surface cells, however, their protein/metabolite levels were not increased as heme induced surface-specific translation repression by increasing 4E-BP1. Therefore, we conclude that heme induced colonic hyperproliferation and hyperplasia by repressing feedback inhibition of proliferation.
Dietary haem stimulates epithelial cell turnover by downregulating feedback inhibitors of proliferation in murine colon.
Sex, Age, Specimen part, Treatment
View SamplesThe risk for colon cancer is associated with nutrition, especially with diets high in red meat. Red meat contains the iron porphyrin pigment heme, which induces cytotoxicity of the colon contents and epithelial hyperproliferation. Using a mouse model, we showed that heme caused damage to the colonic surface epithelium and induced compensatory hyperproliferation. Expression levels of heme- and stress-related genes show that heme affects surface cells and not directly crypt cells. Therefore, injured surface cells should signal to crypt TA cells to induce compensatory hyperproliferation. Surface-specific downregulated inhibitors of proliferation were Wnt inhibitory factor 1, Indian Hedgehog, Bone morphogenic protein 2 and possibly Interleukin-15. Heme also upregulated Amphiregulin, Epiregulin and Cyclooxygenase-2 mRNA in the surface cells, however, their protein/metabolite levels were not increased as heme induced surface-specific translation repression by increasing 4E-BP1. Therefore, we conclude that heme induced colonic hyperproliferation and hyperplasia by repressing feedback inhibition of proliferation.
Dietary haem stimulates epithelial cell turnover by downregulating feedback inhibitors of proliferation in murine colon.
Sex, Age, Specimen part, Treatment
View SamplesProbiotic bacteria, specific representatives of bacterial species that are a common part of the human microbiota, are proposed to deliver health benefits to the consumer by modulation of intestinal function via largely unknown molecular mechanisms. To explore in vivo mucosal responses of healthy adults to probiotics, we obtained transcriptomes in an intervention study following a double-blind placebo-controlled cross-over design. In the mucosa of the proximal small intestine of healthy volunteers, probiotic strains from the species Lactobacillus acidophilus, L. casei and L. rhamnosus each induced differential gene regulatory networks and pathways in the human mucosa. Comprehensive analyses revealed that these transcriptional networks regulate major basal mucosal processes, and uncovered remarkable similarity to response profiles obtained for specific bioactive molecules and drugs. This study elucidates how intestinal mucosa of healthy humans perceive different probiotics and provides avenues for rationally designed tests of clinical applications.
Human mucosal in vivo transcriptome responses to three lactobacilli indicate how probiotics may modulate human cellular pathways.
Specimen part
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