[1] Lactic acidosis time course: MCF7 cells were exposed to lactic acidosis for different length of time. We used microarrays to examine the genomic programs of cells incubated under lactic acidosis for different length of time
Lactic acidosis triggers starvation response with paradoxical induction of TXNIP through MondoA.
Cell line, Treatment
View SamplesThe following abstract from the submitted manuscript describes the major findings of this work.
A role for peroxisome proliferator-activated receptor γ coactivator-1 in the control of mitochondrial dynamics during postnatal cardiac growth.
Specimen part
View SamplesSkeletal muscle adapts to exercise training of various modes, intensities and durations with a programmed gene expression response. This study dissects the independent and combined effects of exercise mode, intensity and duration to identify which exercise has the most positive effects on skeletal muscle health. Full details on exercise groups can be found in: Kraus et al Med Sci Sports Exerc. 2001 Oct;33(10):1774-84 and Bateman et al Am J Cardiol. 2011 Sep 15;108(6):838-44.
Metabolite signatures of exercise training in human skeletal muscle relate to mitochondrial remodelling and cardiometabolic fitness.
Sex, Age, Specimen part, Race, Subject
View SamplesPGC-1 transcription factor was customized to limit its interations to ERRalpha. This mutant (2x9) was used to dissect the transcription activation patterns that are attributable to the PGC1-ERR interaction and PGC-1 actions that are independent of ERR. Inactive mutant with the deleted LLXXL motifs (L2L3) and wt PGC-1 were used as negative and positive controls respectively. BGAL-expressing construct was used to control for non-specific effects of adenoviral infection.
Receptor-selective coactivators as tools to define the biology of specific receptor-coactivator pairs.
No sample metadata fields
View SamplesIn order to propagate a solid tumor, cancer cells must adapt to and survive under various tumor microenvironment (TME) stresses, such as hypoxia or lactic acidosis. To systematically identify genes that modulate cancer cell survival under stresses, we performed genome-wide shRNA screens under hypoxia or lactic acidosis. We discovered that genetic depletion of acetyl-CoA carboxylase (ACACA or ACC1) or ATP citrate lyase (ACLY) protected cancer cells from hypoxia-induced apoptosis. Additionally, loss of ACLY or ACC1 reduced levels and activities of the oncogenic transcription factor ETV4. Silencing ETV4 also protected cells from hypoxia-induced apoptosis and led to remarkably similar transcriptional responses as with silenced ACLY or ACC1, including an anti-apoptotic program. Metabolomic analysis found that while -ketoglutarate levels decrease under hypoxia in control cells, -ketoglutarate is paradoxically increased by hypoxia when ACC1 or ACLY are depleted. Supplementation with -ketoglutarate rescued the hypoxia-induced apoptosis and recapitulated the decreased expression and activity of ETV4 via an epigenetic mechanism. Therefore, ACC1 and ACLY regulate the levels of ETV4 under hypoxia via increased -ketoglutarate. These results reveal that ACC1/ACLY- -ketoglutarate-ETV4 is a novel means by which metabolic states regulate transcriptional output for life vs. death decisions under hypoxia. Since many lipogenic inhibitors are under investigation as cancer therapeutics, our findings suggest that the use of these inhibitors will need to be carefully considered with respect to oncogenic drivers, tumor hypoxia, progression and dormancy. More broadly, our screen provides a framework for studying additional tumor cell stress-adaption mechanisms in the future.
ACLY and ACC1 Regulate Hypoxia-Induced Apoptosis by Modulating ETV4 via α-ketoglutarate.
Specimen part, Cell line
View SamplesCompelling evidence suggests that mitochondrial dysfunction contributes to the pathogenesis of heart failure, including defects in the substrate oxidation, and the electron transport chain (ETC) and oxidative phosphorylation (OXPHOS). However, whether such changes occur early in the development of heart failure, and are potentially involved in the pathologic events that lead to cardiac dysfunction is unknown. To address this question, we conducted transcriptomic/metabolomics profiling in hearts of mice with two progressive stages of pressure overload-induced cardiac hypetrophy: i) cardiac hypertrophy with preserved ventricular function achieved via transverse aortic constriction for 4 weeks (TAC) and ii) decompensated cardiac hypertrophy or heart failure (HF) caused by combining 4 wk TAC with a small apical myocardial infarction. Transcriptomic analyses revealed, as shown previously, downregulated expression of genes involved in mitochondrial fatty acid oxidation in both TAC and HF hearts compared to sham-operated control hearts. Surprisingly, however, there were very few changes in expression of genes involved in other mitochondrial energy transduction pathways, ETC, or OXPHOS. Metabolomic analyses demonstrated significant alterations in pathway metabolite levels in HF (but not in TAC), including elevations in acylcarnitines, a subset of amino acids, and the lactate/pyruvate ratio. In contrast, the majority of organic acids were lower than controls. This metabolite profile suggests bottlenecks in the carbon substrate input to the TCA cycle. This transcriptomic/metabolomic profile was markedly different from that of mice PGC-1a/b deficiency in which a global downregulation of genes involved in mitochondrial ETC and OXPHOS was noted. In addition, the transcriptomic/metabolomic signatures of HF differed markedly from that of the exercise-trained mouse heart. We conclude that in contrast to current dogma, alterations in mitochondrial metabolism that occur early in the development of heart failure reflect largely post-transcriptional mechanisms resulting in impedance to substrate flux into the TCA cycle, reflected by alterations in the metabolome.
Energy metabolic reprogramming in the hypertrophied and early stage failing heart: a multisystems approach.
Sex, Age, Specimen part
View SamplesThe telomerase RNA component (TERC) is a critical determinant of cellular self renewal. Poly(A)-specific ribonuclease (PARN) is required for post-transcriptional maturation of TERC. PARN mutations lead to incomplete 3' end processing and increased destruction of nascent TERC RNA transcripts, resulting in telomerase deficiency and telomere diseases. Here, we determined that overexpression of TERC increased telomere length in PARN-deficient cells and hypothesized that decreasing post-transcriptional 3' oligo-adenylation of TERC would counteract the deleterious effects of PARN mutations. Inhibition of the noncanonical poly(A) polymerase PAP-associated domain–containing 5 (PAPD5) increased TERC levels in PARN-mutant patient cells. PAPD5 inhibition was also associated with increases in TERC stability, telomerase activity, and telomere elongation. Our results demonstrate that manipulating post-transcriptional regulatory pathways may be a potential strategy to reverse the molecular hallmarks of telomere disease. Overall design: mRNA sequencing of induced pluripotent stem cells and 293 cell line.
Posttranscriptional manipulation of TERC reverses molecular hallmarks of telomere disease.
Specimen part, Subject
View SamplesCockayne syndrome (CS) is an autossomal human disorder characterized by premature aging along with other symptoms. At the molecular level, CS is characterized by a deficiency in the Transcription-couple DNA repair pathway caused by a mutation mainly in ERCC6 gene and the absence of its functional protein. It has been shown that the presence of DNA damage and the lack of some functional proteins related to DNA repair constitute a barrier for somatic cell reprogramming. Recently, it was demonstrated that one protein involved in Genome Global Repair controls the expression of an important pluripotent gene, highligting its importance for cellular reprogramming.
Evidence for premature aging due to oxidative stress in iPSCs from Cockayne syndrome.
Specimen part, Disease, Cell line
View SamplesTransient expression of two factors, or from Oct4 alone, resulted in efficient generation of human iPSCs. The reprogramming strategy described revealed a potential transcriptional signature for human iPSCs yet retaining the gene expression of donor cells in human reprogrammed cells free of viral and transgene interference.
Transcriptional signature and memory retention of human-induced pluripotent stem cells.
Sex, Specimen part
View SamplesStem cells are a potential key strategy for treating neurodegenerative diseases in which the generation of new neurons is critical. A better understanding of the characteristics and molecular properties of neural stem cells (NSC) and differentiated neurons can help in assessing neuronal maturity and possibly in devising better therapeutic strategies. We have therefore performed an in-depth gene expression profiling study of the C17.2 NSC line and primary neurons (PN) derived from embryonic mouse brains. Microarray analysis revealed a neuron-specific gene expression signature that distinguishes PN from NSCs, with elevated levels of transcripts involved in neuronal functions such as neurite development, axon guidance, in PN. The same comparison revealed decreased levels of multiple cytokine transcripts such as IFN, TNF, TGF, and IL. Among the differentially expressed genes, we found a statistically significant enrichment of genes in the ephrin, neurotrophin, CDK5 and actin pathways which control multiple neuronal-specific functions. Furthermore, genes involved in cell cycle were among the most significantly changed in PN. In order to better understand the role of cell cycle arrest in mediating NSCs differentiation, we blocked the cell cycle of NSCs with Mitomycin C (MMC) and examined cellular morphology and gene expression signatures. Although these MMC-treated NSCs displayed a neuronal morphology and expressed some neuronal differentiation marker genes, their gene expression patterns was very different from primary neurons. We conclude that: 1) Fully differentiated primary neurons display a specific neuronal gene expression signature; 2) cell-cycle block in NSC does not induce the formation of fully differentiated neurons; 3) Cytokines such as IFN, TNF, TGF and IL are part of normal NSC function and/or physiology; 4) Signaling pathways of ephrin, neurotrophin, CDK5 and actin, related to major neuronal features, are dynamically enriched in genes showing changes in expression level.
Identification of a neuronal gene expression signature: role of cell cycle arrest in murine neuronal differentiation in vitro.
Sex, Specimen part, Cell line
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