This SuperSeries is composed of the SubSeries listed below.
Metabolomic Identification of Subtypes of Nonalcoholic Steatohepatitis.
Age, Specimen part, Treatment
View SamplesMethionine adenosyltransferase (MAT) enzymes generate SAMe (S-adenosylmethionine), the main biological methyl donor. There are two MAT encoding genes in mammals (Mat1a and Mat2a), which show different activities and cellular distribution. Mat1a encodes the enzyme mainly expressed in normal liver. Mat1a ablation in mice results in the spontaneous development of non-alcoholic steatohepatitis (NASH). We observed that SAMe depletion in Mat1a KO mice had three main effects on hepatic lipid metabolism: 1) impaired TG (triglyceride) export via VLDL; 2) impaired mitochondrial FA (fatty acid) oxidation (as evidenced by membrane depolarization, downregulation of Phb1 (prohibitin 1, a mitochondrial chaperone protein) and Mcj/Dnajc15 (endogenous mitochondrial repressor of respiratory chain), and accumulation of long-chain acylcarnitines); and 3) increased FA uptake. The convergence of these three factors induced TG accumulation in LD (lipid droplets). LD expansion confronts hepatocytes with a high demand of PC (phosphatidylcholine) molecules to cover the LD surface since other phospholipids, such as PE (phosphatidylethanolamine), cannot stabilize LD and prevent coalescence. In Mat1a KO this situation is aggravated, since SAMe-dependent PC synthesis via PE methylation is decreased, the PC/PE ratio reduced and mitochondrial FA oxidation impaired. To put a brake to this drain of PC molecules to LD, FA are rerouted in Mat1a KO mice liver to other catabolic (endoplasmic reticulum and peroxisome oxidation) and biosynthetic (ceramides synthesis) pathways, causing oxidative stress, inflammation and fibrosis. SAMe treatment for two months in 8-9 month old Mat1a KO mice ameliorated mitochondrial dysfunction (reduces membrane depolarization, improves Phb1 and Mcj expression, and increases SAMe transport to mitochondria) improving FA oxidation efficiency (FA and acylcarnitine levels decrease), which results in a drastic reduction in TG accumulation. SAMe treatment in Mat1a KO mice resulted in more PC available for proper membrane function, improving liver lipid homeostasis, histology (H&E, Sudan red, Sirius red) and liver injury (ALT, AST).
Metabolomic Identification of Subtypes of Nonalcoholic Steatohepatitis.
Age, Specimen part
View SamplesAllergic (Th2high immunophenotype) asthmatics have a heightened susceptibility to common respiratory viral infections such as human rhinovirus. Evidence suggests that the innate interferon response is deficient in asthmatic/atopic individuals, whilst other studies show no differences in antiviral response pathways. Unsensitized and OVA-sensitized/challenged Th2high (BN rats) and Th2low immunophenotype (PVG rats) animals were inoculated intranasally with attenuated mengovirus (vMC0). Sensitized animals were exposed/unexposed during the acute viral response phase. Cellular and transcriptomic profiling was performed on bronchoalveolar lavage cells. In unsensitized PVG rats, vMC0 elicits a prototypical antiviral response (neutrophilic airways inflammation, upregulation of Th1/type I interferon-related pathways). In contrast, response to infection in the Th2high BN rats was associated with a radically altered intrinsic host response to respiratory viral infection, characterized by macrophage influx/Th2-associated pathways. In sensitized animals, response to virus infection alone was not altered compared to unsensitized animals. However, allergen exposure of sensitized animals during viral infection unleashes a notably exaggerated airways inflammatory response profile orders of magnitude higher in BN versus PVG rats despite similar viral loads. The coexposure responses in the Th2high BN incorporated type I interferon/Th1, alternative macrophage activation/Th2 and Th17 signatures. Similar factors may underlie the hyper-susceptibility to infection-associated airways inflammation characteristic of the human Th2high immunophenotype.
Atopy-Dependent and Independent Immune Responses in the Heightened Severity of Atopics to Respiratory Viral Infections: Rat Model Studies.
Sex, Specimen part, Treatment
View SamplesCardiac muscle differentiation in vivo is guided by sequential growth factor signals, including endoderm-derived diffusible factors, impinging on cardiogenic genes in the developing mesoderm. Previously, by RNA interference in AB2.2 mouse embryonic stem cells (mESCs), we identified the endodermal transcription factor Sox17 as essential for Mesp1 induction in primitive mesoderm and subsequent cardiac muscle differentiation. However, downstream effectors of Sox17 remained to be proven functionally. In this study, we used genome-wide profiling of Sox17-dependent genes in AB2.2 cells, RNA interference, chromatin immunoprecipitation, and luciferase reporter genes to dissect this pathway. Sox17 was required not only for Hhex (a second endodermal transcription factor) but also for Cer1, a growth factor inhibitor from endoderm that, like Hhex, controls mesoderm patterning in Xenopus toward a cardiac fate. Suppressing Hhex or Cer1 blocked cardiac myogenesis, although at a later stage than induction of Mesp1/2. Hhex was required but not sufficient for Cer1 expression. Over-expression of Sox17 induced endogenous Cer1 and sequence-specific transcription of a Cer1 reporter gene. Forced expression of Cer1 was sufficient to rescue cardiac differentiation in Hhex-deficient cells. Thus, Hhex and Cer1 are indispensable components of the Sox17 pathway for cardiopoiesis in mESCs, acting at a stage downstream from Mesp1/2.
Hhex and Cer1 mediate the Sox17 pathway for cardiac mesoderm formation in embryonic stem cells.
Cell line
View SamplesWe examined global gene expression patterns in response to PGC-1 expression in cells derived from liver or muscle.
Direct link between metabolic regulation and the heat-shock response through the transcriptional regulator PGC-1α.
Specimen part
View SamplesCell adhesion plays an important role in determining cell shape and function in a variety of physiological and pathophysiological conditions. While links between metabolism and cell adhesion were previously suggested, the exact context and molecular details of such a cross-talk remain incompletely understood.
Inhibition of Adhesion Molecule Gene Expression and Cell Adhesion by the Metabolic Regulator PGC-1α.
Specimen part, Cell line
View SamplesSecreted proteins serve pivotal roles in the development of multicellular organisms, acting as structural matrix, extracellular enzymes and signal molecules. In this study we demonstrate, unexpectedly, that PGC-1, a critical transcriptional co-activator of metabolic gene expression, functions to down-regulate expression of diverse genes encoding secreted molecules and extracellular matrix (ECM) components to modulate the secretome. We show that both endogenous and exogenous PGC-1 down-regulate expression of numerous genes encoding secreted molecules. Mechanistically, results obtained using mRNA stability measurements as well as intronic RNA expression analysis are consistent with a transcriptional effect of PGC-1 on expression of genes encoding secreted proteins. Interestingly, PGC-1 requires the central heat shock response regulator HSF1 to affect some of its targets, and both factors co-reside on several target genes encoding secreted molecules in cells. Finally, using a mass spectrometric analysis of secreted proteins, we demonstrate that PGC-1 modulates the secretome of mouse embryonic fibroblasts (MEFs).
Control of Secreted Protein Gene Expression and the Mammalian Secretome by the Metabolic Regulator PGC-1α.
Specimen part
View SamplesHuman umbilical vein endothelial cells (HUVECs) were transduced with either MIY-N1IC (Notch1 intracellular domain) or MIY vector control. The cells were sorted for YFP, and RNA was extracted using Trizol (Invitrogen) and analyzed by the Affymetrix Human Genome U133 Plus 2.0 Array. Results were analyzed using the GCRMA algorithm to identify genes with a minimum of 2-fold induction or reduction. This global gene expression study was used to identify Notch targets in the endothelium.
Notch initiates the endothelial-to-mesenchymal transition in the atrioventricular canal through autocrine activation of soluble guanylyl cyclase.
Specimen part
View SamplesInfection-associated inflammatory stress during pregnancy is the most common cause of fetal growth restriction. Treatment strategies for protection of at-risk mothers are limited. Employing mouse models, we demonstrate that oral treatment during pregnancy with a microbial-derived immunomodulator (OM85), markedly reduces risk for fetal loss/growth restriction resulting from maternal challenge with bacterial LPS or influenza. Focusing on LPS exposure, we demonstrate that the key molecular indices of maternal inflammatory stress (RANTES, MIP-1a, CCL2, KC, G-CSF) in gestational tissues/serum, are abrogated by OM85 pretreatment. Systems-level analyses of RNASeq data revealed that OM85 pretreatment selectively tunes LPS-induced activation in maternal gestational tissues for attenuated expression of TNF-, IL1-, and IFNg- driven proinflammatory networks, without constraining Type1-IFN-associated networks central to first-line anti-microbial defense. This study suggests that broad-spectrum protection-of-pregnancy against infection-associated inflammatory stress, without compromising capacity for efficient pathogen eradication, represents an achievable therapeutic goal. Overall design: Mice were exposed to four treatment conditions (sham control, OM85 pretreatment, LPS challenge, or OM85 pretreatment followed by LPS challenge). Gene expression patterns were profiled in two different tissues (uterus and decidua). There were six animals in each experimental group.
Protection against maternal infection-associated fetal growth restriction: proof-of-concept with a microbial-derived immunomodulator.
Specimen part, Cell line, Treatment, Subject
View SamplesWe found that the non-essential amino acid L-Proline (L-Pro) acts as a signaling molecule that promotes the conversion of embryonic stem cells (ESCs) into mesenchymal-like, spindle-shaped, highly motile, invasive pluripotent stem cells. This embryonic stem cell-to-mesenchymal-like transition (esMT) is accompanied by a genome-wide remodeling of the transcriptome
L-Proline induces a mesenchymal-like invasive program in embryonic stem cells by remodeling H3K9 and H3K36 methylation.
Cell line
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