Aims: To determine the changes in the Arabidopsis axillary bud transcriptome in response to changes in the red light (R) to far red light (FR) ratio (R:FR).
Abscisic acid regulates axillary bud outgrowth responses to the ratio of red to far-red light.
Specimen part, Treatment
View SamplesCancer cells interact with surrounding stromal fibroblasts during tumorigenesis, but the complex molecular rules that govern these interactions remain poorly understood, thus hindering the development of therapeutic strategies to target cancer stroma. We have taken a mathematical approach to begin defining these rules by performing large-scale quantitative analysis of fibroblast effects on cancer cell proliferation across more than four hundred heterotypic cell line pairings. Systems-level modeling of this complex dataset using singular value decomposition revealed that normal tissue fibroblasts variably express at least two functionally distinct activities, one which reflects transcriptional programs associated with activated mesenchyme, that act either coordinately or at cross-purposes to modulate cancer cell proliferation. To gain insight into the molecular identity of these fibroblast activities, we isolated RNA from 36 human skin and lung fibroblast cell line monocultures from Coriell Repositories or ATCC and performed microarray-based gene expression profiling using Affymetrix gene chips.
Systems-level modeling of cancer-fibroblast interaction.
Sex, Age, Race
View SamplesTo determine the effects of age and lipoic acid supplementation on hepatic gene expression, we fed young (3 months) and old (24 months) male Fischer 344 rats a diet with or without 0.2% (w/w) R--lipoic acid (LA) for two weeks. Total RNA isolated from liver tissue was analyzed by Affymetrix microarray to examine changes in transcriptional profile. Results showed an increase in pro-inflammatory gene expression in the aging liver, with increased immune cell function and tissue remodeling genes, representing 45% of the age-related transcriptome changes. Increased inflammation was corroborated by increases in soluble ICAM1 levels with age. There were also observed age-related increases in transcription of genes related to lipid and cholesterol synthesis including Acetyl CoA Carboxylase (Acacb) and Fatty acid Synthase (Fasn). Supplementation of old animals with LA did not reverse this necro-inflammatory phenotype, yet limited age-associated hepatic dyslipidemia. Dietary LA further affected a small but concerted number of hepatic genes regardless of age. These included declines in lipid and bile synthesis genes. Decline in lipid synthesis genes was further corroborated by a decrease in Fasn and Acc protein levels. Intriguingly, LA also altered the expression of genes governing circadian rhythm, most notably Bmal1, Npas2, and Per2, which changed in a coordinated manner with respect to their rhythmic transcription. Thus, advanced age is associated with a necro-inflammatory phenotype and increased lipid synthesis, while chronic LA supplementation influences hepatic genes associated with energy metabolism and circadian rhythm regardless of age.
R-α-lipoic acid does not reverse hepatic inflammation of aging, but lowers lipid anabolism, while accentuating circadian rhythm transcript profiles.
Sex, Age, Specimen part
View SamplesIn cytotoxic T cells (CTL), Protein Kinase B /Akt is activated by the T cell antigen receptor (TCR) and the cytokine Interleukin 2 (IL2), in part by phosophorylation of Akt by Phospholipid dependent kinase 1 (PDK1).
Protein kinase B controls transcriptional programs that direct cytotoxic T cell fate but is dispensable for T cell metabolism.
Specimen part
View SamplesNext Generation RNA Sequencing was carried out on human paired left and right atrial appendages from patients with and without Atrial Fibrillation. EdgeR software was used to show a total of 247 genes were found to have significant differential expression between left and right atria. Overall design: Left and Right atrial appendages from 5 patients in Sinus Rhythm and 5 patients in atrial fibrillation were subjected to RNA sequencing and differential gene expression using EdgeR.
Differentially expressed genes for atrial fibrillation identified by RNA sequencing from paired human left and right atrial appendages.
Sex, Specimen part, Subject
View SamplesThe identification of Atg16L1 as a susceptibility gene has implicated antibacterial autophagy in the pathogenesis of Crohn''s disease, a major type of inflammatory bowel disease (IBD). However, the role of Atg16L1 during extracellular bacterial infections of the intestine has not been sufficiently examined and compared to the function of other IBD susceptibility genes such as Nod2. We now find that Atg16L1 mutant mice are extraordinarily resistant to intestinal disease induced by the model bacterial pathogen Citrobacter rodentium. We further demonstrate that Atg16L1 deficiency alters the intestinal environment to mediate an enhanced immune response that is dependent on monocytic cells, and that Atg16L1/Nod2 double mutant mice lose this advantage. These results reveal an unappreciated immuno-suppressive function of an IBD gene, and raise the possibility that gene variants that affect the autophagy pathway were evolutionarily maintained to protect against certain life-threatening infections. Overall design: Twenty samples have been analyzed. All are colonic tissue from mice. Controls are uninfected WT mice, uninfected Atg16L1 mutant mice (Atg16L1HM) (n=3/genotype). Treatment conditions are tissue from WT and Atg16L1 mutant mice 6 days after C. rodentium infection (n=4/genotype) and 15 days after infection (n=3/genotype).
A deficiency in the autophagy gene Atg16L1 enhances resistance to enteric bacterial infection.
Specimen part, Subject
View SamplesMetastasis-initiating cells dynamically adapt to the distinct microenvironments of different organs, but these early adaptations are poorly understood due to the limited sensitivity of in situ transcriptomics. We developed fluorouracil-labeled RNA sequencing (Flura-seq) for in situ analysis with unprecedented sensitivity. Flura-seq utilizes cytosine deaminase (CD) to convert fluorocytosine to fluorouracil, covalently labeling nascent RNA for purification and sequencing. Flura-seq revealed that breast cancer micrometastases in lung and brain exhibit unique, reversible gene signatures depending on the microenvironment. Specifically, the mitochondrial electron transport Complex I and the NRF2-driven antioxidant programs were induced in oxygen-rich pulmonary micrometastases, compared to mammary tumors or brain micrometastases. Loss of Complex I activity, and antioxidant supplementation potentiated pulmonary metastatic growth. We confirm lung metastasis-specific NRF2 overexpression in clinical samples, thus validating Flura-seq's utility in identifying clinically actionable microenvironmental adaptations in early metastasis. The sensitivity, robustness and economy of Flura-seq are broadly applicable beyond cancer research. Overall design: Examination of 5-FU labeled RNAs in cancer cells present in different organs
Flura-seq identifies organ-specific metabolic adaptations during early metastatic colonization.
Cell line, Subject
View SamplesSirtuins are a family of protein deacetylases, deacylases, and ADP-ribosyltransferases that regulate life span, control the onset of numerous age-associated diseases, and mediate metabolic homeostasis. We have uncovered a novel role for the mitochondrial sirtuin SIRT4 in the regulation of hepatic lipid metabolism during changes in nutrient availability. We show that SIRT4 levels decrease in the liver during fasting and that SIRT4 null mice display increased expression of hepatic peroxisome proliferator activated receptor (PPAR ) target genes associated with fatty acid catabolism. Accordingly, primary hepatocytes from SIRT4 knockout (KO) mice exhibit higher rates of fatty acid oxidation than wild-type hepatocytes, and SIRT4 overexpression decreases fatty acid oxidation rates. The enhanced fatty acid oxidation observed in SIRT4 KO hepatocytes requires functional SIRT1, demonstrating a clear cross talk between mitochondrial and nuclear sirtuins. Thus, SIRT4 is a new component of mitochondrial signaling in the liver and functions as an important regulator of lipid metabolism.
SIRT4 represses peroxisome proliferator-activated receptor α activity to suppress hepatic fat oxidation.
Sex, Specimen part
View SamplesCalorie restriction (CR) is a dietary intervention that extends lifespan and healthspan in a variety of organisms. CR improves mitochondrial energy production, fuel oxidation and reactive oxygen species scavenging in skeletal muscle and other tissues, and these processes are thought to be critical to the benefits of CR. PGC-1a is a transcriptional coactivator that regulates mitochondrial function and is induced by CR. Consequently, many of the mitochondrial and metabolic benefits of CR are attributed to increased PGC-1a activity. To test this model for the first time, we examined the metabolic and mitochondrial response to CR in mice lacking skeletal muscle PGC-1a (MKO). Surprisingly, MKO mice demonstrated a normal improvement in glucose homeostasis in response to CR, indicating that skeletal muscle PGC-1a is dispensable for the whole-body benefits of CR. In contrast, gene expression profiling and electron microscopy demonstrated that PGC-1a is required for the full CR-induced increases in mitochondrial gene expression and mitochondrial density in skeletal muscle. These results demonstrate that PGC-1a is a major regulator of the mitochondrial response to CR in skeletal muscle, but surprisingly show that neither PGC-1a nor mitochondrial biogenesis in skeletal muscle are required for the metabolic benefits of CR.
Skeletal muscle transcriptional coactivator PGC-1α mediates mitochondrial, but not metabolic, changes during calorie restriction.
Specimen part
View SamplesTumor cells exhibit aberrant metabolism characterized by high glycolysis even in the presence of oxygen. This metabolic reprogramming, known as the Warburg effect, provides tumor cells with the substrates and redox potential required for the generation of biomass. Here, we show that the mitochondrial NAD-dependent deacetylase SIRT3 is a crucial regulator of the Warburg effect. SIRT3 loss promotes a metabolic profile consistent with high glycolysis required for anabolic processes in vivo and in vitro. Mechanistically, SIRT3 mediates metabolic reprogramming independently of mitochondrial oxidative metabolism and through HIF1a, a transcription factor that controls expression of key glycolytic enzymes. SIRT3 loss increases reactive oxygen species production, resulting in enhanced HIF1a stabilization. Strikingly, SIRT3 is deleted in 40% of human breast cancers, and its loss correlates with the upregulation of HIF1a target genes. Finally, we find that SIRT3 overexpression directly represses the Warburg effect in breast cancer cells. In sum, we identify SIRT3 as a regulator of HIF1a and a suppressor of the Warburg effect.
SIRT3 opposes reprogramming of cancer cell metabolism through HIF1α destabilization.
Specimen part
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