C.pn potentiated hyperlipidemia-induced inflammasome activity in cultured macrophages and in foam cells in atherosclerotic lesions of Ldlr/ mice. We discovered that C.pn-induced extracellular IL-1 triggers a negative feedback loop to inhibit GPR109a and ABCA1 expression and cholesterol efflux leading to accumulation of intracellular cholesterol and foam cell formation. Gpr109a and Abca1 were both upregulated in plaque lesions in Nlrp3/ mice in both hyperlipidemic and C.pn infection models.
Chlamydia pneumoniae Hijacks a Host Autoregulatory IL-1β Loop to Drive Foam Cell Formation and Accelerate Atherosclerosis.
Specimen part, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
MAFG is a transcriptional repressor of bile acid synthesis and metabolism.
Treatment
View SamplesSpecific bile acids are potent signaling molecules that modulate metabolic pathways affecting lipid, glucose and bile acid homeostasis, and the microbiota. Bile acids are synthesized from cholesterol in the liver, and the key enzymes involved in bile acid synthesis (Cyp7a1, Cyp8b1) are regulated transcriptionally by the nuclear receptor FXR. We have identified an FXR-regulated pathway upstream of a transcriptional repressor that controls multiple bile acid metabolism genes. We identify MafG as an FXR target gene and show that hepatic MAFG overexpression represses genes of the bile acid synthetic pathway and modifies the biliary bile acid composition. In contrast, loss-of-function studies using MafG(+/-) mice causes de-repression of the same genes with concordant changes in biliary bile acid levels. Finally, we identify functional MafG response elements in bile acid metabolism genes using ChIP-seq analysis. Our studies identify a molecular mechanism for the complex feedback regulation of bile acid synthesis controlled by FXR
MAFG is a transcriptional repressor of bile acid synthesis and metabolism.
Treatment
View SamplesHumoral responses of mice specifically deleted for Moz (a histone acetyltransferase) or c-Myb (a transcription factor) in B cells were aberrant. RNA-sequencing analysis was performed to assess gene expression differences compared to wild-type controls in germinal center B cells or plasmablasts. Overall design: Moz f/f Aicda1-Cre, Aicda1-Cre, Myb f/f Cd23-Cre, Mybf/f (no cre) mice were immunized with NP-KLH precipitated in alum and germinal center B cells were sort-purified. Secondary plasmablasts were sort-purified from immunized mice boosted with NP-KLH in PBS (Myb experiment). Two independent experiments were conducted.
Regulation of germinal center responses and B-cell memory by the chromatin modifier MOZ.
Specimen part, Subject
View SamplesCellular lipid requirements are achieved through a combination of biosynthesis and import programs. Using isotope tracer analysis, we show that type I interferon (IFN) signaling rapidly shifts the balance of these programs by decreasing synthesis and increasing import of cholesterol and long chain fatty acids. Genetically enforcing this metabolic shift in macrophages is sufficient to render mice resistant to viral challenge, demonstrating the importance of reprogramming the balance of these two metabolic pathways in vivo. Unexpectedly, mechanistic studies reveal that limiting flux through the cholesterol biosynthetic pathway spontaneously engages a type I IFN response in a STING-dependent manner. The upregulation of type I IFNs was traced to a decrease in the pool size of synthesized cholesterol, and could be inhibited by replenishing cells with free cholesterol. Taken together, these studies delineate a metabolic-inflammatory circuit that links perturbations in cholesterol biosynthesis with activation of innate immunity. Overall design: shRNA to SREBF1 (shSREBP1) or SREBF2 (shSREBP2) were stably introduced via 3rd generation lentivirus into human THP1 monocytic cells under puromycin selection. Non-targeting shRNA scramble was used for a control (shControl). shControl, shSREBP1 and shSREBP2 modified cell types were analyzed by RNA-seq in duplicate.
Limiting Cholesterol Biosynthetic Flux Spontaneously Engages Type I IFN Signaling.
No sample metadata fields
View SamplesExpression profiling of hepatocytes-derived ductal cells with properties intermediate between mature hepatocytes and cholangiocytes Overall design: Chimeric adult mice were generated where mature hepatocytes were marked with a fluorescent red marker. Chronic injury was induced for ~6weeks and three cell types were isolated by FACS (Influx, BD) for expression analysis by RNAseq based on cell surface phenotype and origin: hepatocytes (n=3), hepatocyte-derived oval cells (1c3+, n=5), and cholangiocyte-derived oval cells (1c3+, n=5).
Bipotential adult liver progenitors are derived from chronically injured mature hepatocytes.
No sample metadata fields
View SamplesThe transcriptomes of four subpopulations of beta cells isolated by FACS from five healthy human donors. Populations were defined using cell surface-labeling antibodies, avoiding the need for fixation. Overall design: There are 5 biological replicates of 4 different cell types. Each donor yielded all 4 subtypes.
Human islets contain four distinct subtypes of β cells.
Specimen part, Subject
View Samplesassess the efficacy of Pimasertib to characterize its mechanism of action
Combination of the MEK inhibitor pimasertib with BTK or PI3K-delta inhibitors is active in preclinical models of aggressive lymphomas.
Cell line, Treatment, Time
View SamplesBRAF oncogene is mutated in ~50% of human cutaneous melanomas. The BRAF V600E mutation leads to constitutive activation of the mitogen-activated protein kinase (MAPK) pathway fuelling cancer growth. The inhibitors of BRAF V600E (BRAFi), lead to massive and high response rate. However, BRAFi-resistant cells that operate as a cellular reservoir for relapses severely limits the duration of the clinical response. The recent depiction of these resistant cells did not identify druggable targets to ensure long-term survival under BRAFi. Here, we identify the aryl hydrocarbon receptor (AhR) as a target to eradicate resistant cells. We show that BRAFi bind to AhR on a new site, named beta-pocket, and reprogram gene expression independently of its partner ARNT. beta-pocket activation induces a pigmentation signature, which is associated to BRAFi-induced cell death of sensitive BRAF V600E melanoma cells and tumour shrinkage. Intriguingly, in resistant cells, BRAFi does not induced a pigmentation signature since these cells display another AhR program; AhR-ARNT dependant. By this way, AhR directs several key BRAFi-resistant genes. At single cell level, this constitutive activation of AhR-ARNT is identified in rare cells before BRAFi-treatment of melanoma tumours and an enrichment of these alpha-cells is observed under BRAFi. Our data strongly suggest that an endogenous AhR ligand activates AhR-ARNT via the canonical AhR pocket (alpha-pocket), thus favouring BRAFi-resistant gene expression. Importantly, we identify the clinically compatible AhR antagonist, the resveratrol (RSV), able to abrogate the deleterious constitutive activation of AhR and to reduce the cellular reservoir for the relapse. Taken together, this work reveals that constitutive AhR signalling drives BRAFi resistance and constitutes a therapeutic target to achieve long-term patient survival under BRAFi. More broadly, the constitutive activation of AhR by endogenous ligands is in line with the ability of UV radiations to generate potent AhR ligands and to favour melanoma onset. Overall design: Total RNA isolated from 12 human melanoma cell lines (501Mel) after different treatments was subjected to multiplexed RNA-sequencing using Illumina NextSeq500 sequencing tehnology.
Sustained activation of the Aryl hydrocarbon Receptor transcription factor promotes resistance to BRAF-inhibitors in melanoma.
Specimen part, Cell line, Subject
View SamplesAbstract: The antimalarial activity of the antibiotic thiostrepton has long been attributed to inhibition of apicoplast protein synthesis through binding of apicoplast ribosomal RNA. However, the kinetics of parasite death upon thiostrepton treatment differ from those seen for other inhibitors of apicoplast housekeeping functions. We have analysed global changes in gene expression of the malaria parasite, Plasmodium falciparum, in an attempt to shed light on the responses of the parasite to this drug. Our results indicate a delay in gene expression profiles of thiostrepton-treated parasites. A small number of genes appear to be regulated outside of this trend; our data suggest a response from genes encoding components of the mitochondrial translational machinery, while little response is seen from genes encoding apicoplast-targeted proteins. Our findings are consistent with an effect of thiostrepton on mitochondrial protein synthesis, and thus warrant a re-evaluation of the target of thiostrepton in Plasmodium. They also provide some suggestion of mitochondrion nucleus signalling in the parasite.
Transcript-level responses of Plasmodium falciparum to thiostrepton.
Treatment
View Samples