TGR5 (Gpbar1) is a G protein-coupled receptor responsive to bile acids (BAs), which is expressed in different non-parenchymal cells of the liver, including biliary epithelial cells, liver-resident macrophages, sinusoidal endothelial cells (LSECs) and activated hepatic stellate cells (HSCs). Mice with targeted deletion of TGR5 are more susceptible towards cholestatic liver injury induced by cholic acid-feeding and bile duct ligation, resulting in a reduced proliferative response and increased liver injury. Conjugated lithocholic acid (LCA) represents the most potent TGR5 BA ligand and LCA-feeding has been used as a model to rapidly induce severe cholestatic liver injury in mice. Thus, TGR5 knockout (KO) mice and wildtype littermates were fed a diet supplemented with 1%LCA for 84 hours. Liver injury and gene expression changes induced by the LCA-diet revealed an enrichment of pathways associated with inflammation, proliferation and matrix remodelling. Knockout of TGR5 in mice caused upregulation of endothelin-1 (ET-1) expression in the livers. Analysis of TGR5-dependent ET-1 signalling in isolated LSECs and HSCs demonstrated that TGR5 activation reduces ET-1 expression and secretion from LSECs and triggers internalization of the ET-1 receptor in HSCs dampening ET-1 responsiveness. Thus, we identified two independent mechanisms by which TGR5 inhibits ET-1 signalling and modulates portal pressure.
The G Protein-Coupled Bile Acid Receptor TGR5 (Gpbar1) Modulates Endothelin-1 Signaling in Liver.
Sex
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Early detection of lung cancer by molecular markers in endobronchial epithelial-lining fluid.
Specimen part, Disease, Disease stage, Subject
View SamplesWe investigated whether biomarker analysis in endobronchial epithelial lining fluid (ELF) collected by bronchoscopic microsampling may be useful for a definitive preoperative diagnosis. Therefore we compared ELF samples close to nodule and from the contralateral site from patients with malignant or benign diagnosis.
Early detection of lung cancer by molecular markers in endobronchial epithelial-lining fluid.
Specimen part, Disease, Disease stage, Subject
View SamplesJournal : Blood. 2009 Jul 9;114(2):469-77. Epub 2009 May 13.
Endothelial deletion of hypoxia-inducible factor-2alpha (HIF-2alpha) alters vascular function and tumor angiogenesis.
Specimen part
View SamplesNon-small cell lung cancer (NSCLC) is the leading cause of cancer deaths worldwide. The oxygen-sensitive Hypoxia Inducible Factor (HIF) transcriptional regulators HIF-1 and HIF-2 are overexpressed in many human NSCLCs, and constitutive HIF-2 activity can promote murine lung tumor progression, suggesting that HIF proteins may be effective NSCLC therapeutic targets. To investigate the consequences of inhibiting HIF activity in lung cancers, we deleted Hif-1 or Hif-2 in an established KrasG12D-driven murine NSCLC model. Deletion of Hif-1 had no obvious effect on tumor growth, whereas Hif-2 deletion resulted in an unexpected increase in tumor burden that correlated with reduced expression of the candidate tumor suppressor gene Scgb3a1 (HIN-1).
HIF-2alpha deletion promotes Kras-driven lung tumor development.
No sample metadata fields
View SamplesHuman renal cell carcinomas (RCC) have differential expression of HIF-1alpha and HIF-2alpha, depending on VHL genotype and other events.
HIF-alpha effects on c-Myc distinguish two subtypes of sporadic VHL-deficient clear cell renal carcinoma.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesIdiopathic pulmonary fibrosis (IPF) is associated with the accumulation of collagen-secreting fibroblasts and myofibroblasts in the lung parenchyma. Many mechanisms contribute to their accumulation, including resistance to apoptosis. In previous work, we showed that exposure to the pro-inflammatory cytokines, TNF- and IFN- reverses fibroblast resistance to apoptosis. The goal of this study was to investigate the underlying mechanism. Based on an initial interrogation of the transcriptomes of unstimulated and TNF- and IFN--stimulated primary lung fibroblasts and the lung fibroblast cell line, MRC5, we show here that among Fas-signaling pathway molecules, Fas expression was increased ~6-fold in an NF-B and p38mapk-dependent fashion. Prevention of the increase in Fas expression using Fas siRNAs blocked the ability of TNF- and IFN- to sensitize fibroblasts to Fas ligation induced-apoptosis; while enforced adenovirus-mediated Fas overexpression was sufficient to overcome basal resistance to Fas-induced apoptosis. Examination of lung tissues from IPF patients revealed low to absent staining of Fas in fibroblastic cells of fibroblast foci. Collectively, these findings suggest that increased expression of Fas is necessary and sufficient to overcome the resistance of lung fibroblasts to Fas-induced apoptosis. They also suggest that approaches aimed at increasing Fas expression by lung fibroblasts and myofibroblasts may be therapeutically relevant.
Increased cell surface Fas expression is necessary and sufficient to sensitize lung fibroblasts to Fas ligation-induced apoptosis: implications for fibroblast accumulation in idiopathic pulmonary fibrosis.
Specimen part, Treatment
View SamplesLung tumors
Analysis of orthologous gene expression between human pulmonary adenocarcinoma and a carcinogen-induced murine model.
No sample metadata fields
View SamplesILLUMINATE (Investigation of Lipid Level Management to Understand its Impact in Atherosclerotic Events), the phase 3 morbidity and mortality trial of torcetrapib, a cholesteryl ester transfer protein (CETP) inhibitor, identified previously undescribed changes in plasma levels of potassium, sodium, bicarbonate, and aldosterone. A key question after this trial is whether the failure of torcetrapib was a result of CETP inhibition or of some other pharmacology of the molecule. The direct effects of torcetrapib and related molecules on adrenal steroid production were assessed in cell culture using the H295R as well as the newly developed HAC15 human adrenal carcinoma cell lines. Torcetrapib induced the synthesis of both aldosterone and cortisol in these two in vitro cell systems. Analysis of steroidogenic gene expression indicated that torcetrapib significantly induced the expression of CYP11B2 and CYP11B1, two enzymes in the last step of aldosterone and cortisol biosynthesis pathway, respectively. Transcription profiling indicated that torcetrapib and angiotensin II share overlapping pathways in regulating adrenal steroid biosynthesis. Hormone-induced steroid production is mainly mediated by two messengers, calcium and cAMP. An increase of intracellular calcium was observed after torcetrapib treatment, whereas cAMP was unchanged. Consistent with intracellular calcium being the key mediator of torcetrapibs effect in adrenal cells, calcium channel blockers completely blocked torcetrapib-induced corticoid release and calcium increase. A series of compounds structurally related to torcetrapib as well as structurally distinct compounds were profiled. The results indicate that the pressor and adrenal effects observed with torcetrapib and related molecules are independent of CETP inhibition.
Torcetrapib induces aldosterone and cortisol production by an intracellular calcium-mediated mechanism independently of cholesteryl ester transfer protein inhibition.
Specimen part, Cell line, Time
View SamplesA transcription factor Nkx2-1 (also known as TTF-1) regulates the expression of different sets of genes. Gene expression analysis was performed using mRNAs from Nkx2-1-induced A549 cells compared to that from the control A549 cells. We used microarrays to detail the global program of gene expression controlled by Nkx2-1 and identified distinct classes of up-regulated and down-regulated genes.
Kras(G12D) and Nkx2-1 haploinsufficiency induce mucinous adenocarcinoma of the lung.
Cell line
View Samples