Metabolic and transcriptional response to cofactor perturbations in Escherichia coli
Ontology highlight
ABSTRACT:
ORGANISM(S): Escherichia coli Escherichia coli str. K-12 substr. MG1655
PROVIDER: GSE20374 | GEO | 2010/02/18
SECONDARY ACCESSION(S): PRJNA125479
REPOSITORIES: GEO
Similar Datasets
Project description:Metabolic cofactors such as NADH and ATP play important roles in a large number of cellular reactions and it is of great interest to dissect the role of these cofactors in different aspects of metabolism. Towards this goal, we overexpressed NADH oxidase and the soluble F1-ATPase in Escherichia coli to lower the level of NADH and ATP, respectively. We used a systems biology approach to study the response to these perturbations by measuring global transcription profiles, metabolic fluxes and the metabolite levels. We integrated information from the different measurements using network-based methods to identify high-scoring networks in a global interaction map that included protein interactions, transcriptional regulation and metabolism. The results revealed that the action of many global transcription factors such as ArcA, Fnr, CRP and IHF commonly involved both NADH and ATP while others were influential only in one of the pertubations. In general, overexpressing NADH oxidase invokes response in widespread aspects of metabolism involving the redox cofactors (NADH and NADPH) while ATPase has a more focused response to restore ATP level by enhancing proton translocation mechanisms and repressing biosynthesis. Interestingly, NADPH played a key role in restoring redox homeostasis through the concerted activity of isocitrate dehydrogenase and UdhA transhydrogenase. We present a reconciled network of regulation that illustrates the overlapping and distinct aspects of metabolism controlled by NADH and ATP. Our study contributes to the general understanding of redox and energy metabolism and should help in developing metabolic engineering strategies in E. coli. The experimental design involves measuring transcriptome in three strains (in triplicates) of E. coli during mid-exponential phase of growth on MOPS media supplemented with glucose. The three strains are: 1. REF: MG1655/pAK80 (MG1655 transformed with a plasmid with no insert) 2. NOX: MG1655/pAC06 (MG1655 transformed with a plasmid containing NADH oxidase) 3. ATPase: MG1655/pCP41 (MG1655 transformed with a plasmid containing soluble ATPase) RNA was extracted using Qiagen RNeasy kit and processes according to Affymetrix® guidelines. The quality of RNA was verified using BioAnalyzer (Agilent BioSystems) and the electropherograms are shown in the file âRNA quality.pdfâ. Samples 1-3 are REF, Samples 4-6 are NOX and Samples 7-9 are ATPase. The fragmented cRNA was hybridized to E. coli Genome 2.0 chips.
2010-02-21 | E-GEOD-20374 | biostudies-arrayexpress
Project description:When the yeast Saccharomyces cerevisiae is subjected to increasing glycolytic fluxes under aerobic conditions, there is a threshold value of the glucose uptake rate at which the metabolism shifts from being purely respiratory to mixed respiratory and fermentative. This shift is characterized by ethanol production, a phenomenon known as the Crabtree effect due to its analogy with lactate overflow in cancer cells. It is well known that at high glycolytic fluxes there is glucose repression of respiratory pathways resulting in a decrease in the respiratory capacity. Despite many years of detailed studies on this subject, it is not known whether the onset of the Crabtree effect (or overflow metabolism) is due to a limited respiratory capacity or caused by glucose-mediated repression of respiration. We addressed this issue by increasing respiration in S. cerevisiae by introducing a heterologous alternative oxidase, and observed reduced aerobic ethanol formation. In contrast, increasing non-respiratory NADH oxidation by overexpression of a water-forming NADH oxidase reduced aerobic glycerol formation. The metabolic response to elevated alternative oxidase occurred predominantly in the mitochondria, while NADH oxidase affected genes that catalyze cytosolic reactions. Moreover, NADH oxidase restored the deficiency of cytosolic NADH dehydrogenases in S. cerevisiae. These results indicate that NADH oxidase localizes in the cytosol, while alternative oxidase is directed to the mitochondria. The onset of aerobic ethanol formation is demonstrated to be a consequence of an imbalance in mitochondrial redox balancing. In addition to answering fundamental physiological questions, our findings are relevant for all biomass derived applications of S. cerevisiae. Experiment Overall Design: Heterologous gene expression in chemostats using Affymetrix Yeast Genome 2.0 arrays. Total RNA extraction and sample preparation, hybridization was done according to the manufacturer's protocol.
2008-06-14 | E-GEOD-6277 | biostudies-arrayexpress
Project description:Saccharopolyspora erythraea is used for industrial-scale production of erythromycin. To explore the physiological role of co-factors in regulation of primary and secondary metabolism of S. erythraea, we initially overexpressed the endogenous F1-ATPase in an erythromycin high-producing strain, E3. The engineered strain is named EA. The F1-ATPase expression resulted in a lower [ATP]/[ADP] ratio, which was accompanied by a dramatic increased production of a reddish pigment and a decreased erythromycin production. Transcriptional analysis revealed that the intracellular [ATP]/[ADP] ratio appeared to exert a global regulation on the metabolism of S.erythraea, and the lower [ATP]/[ADP] ratio induced physiological changes to restore the energy balance, mainly via pathways that tend to produce ATP or NADH. The results also indicated a state of redox stress in the engineered strain, which was correlated to the alteration of electron transport at the branch of the terminal oxidases.
2020-02-26 | GSE134767 | GEO
Project description:When the yeast Saccharomyces cerevisiae is subjected to increasing glycolytic fluxes under aerobic conditions, there is a threshold value of the glucose uptake rate at which the metabolism shifts from being purely respiratory to mixed respiratory and fermentative. This shift is characterized by ethanol production, a phenomenon known as the Crabtree effect due to its analogy with lactate overflow in cancer cells. It is well known that at high glycolytic fluxes there is glucose repression of respiratory pathways resulting in a decrease in the respiratory capacity. Despite many years of detailed studies on this subject, it is not known whether the onset of the Crabtree effect (or overflow metabolism) is due to a limited respiratory capacity or caused by glucose-mediated repression of respiration. We addressed this issue by increasing respiration in S. cerevisiae by introducing a heterologous alternative oxidase, and observed reduced aerobic ethanol formation. In contrast, increasing non-respiratory NADH oxidation by overexpression of a water-forming NADH oxidase reduced aerobic glycerol formation. The metabolic response to elevated alternative oxidase occurred predominantly in the mitochondria, while NADH oxidase affected genes that catalyze cytosolic reactions. Moreover, NADH oxidase restored the deficiency of cytosolic NADH dehydrogenases in S. cerevisiae. These results indicate that NADH oxidase localizes in the cytosol, while alternative oxidase is directed to the mitochondria. The onset of aerobic ethanol formation is demonstrated to be a consequence of an imbalance in mitochondrial redox balancing. In addition to answering fundamental physiological questions, our findings are relevant for all biomass derived applications of S. cerevisiae. Keywords: Genetic Modification
2007-02-01 | GSE6277 | GEO
Project description:Knowledge about effects of cofactor perturbation on cellular metabolism is scarce with respect to Saccharopolyspora erythraea. The water-forming NADH oxidase (NOX) from Streptococcus pneumonia was expressed in S.erythraea E3, an important industrial strain for erythromycin production, at three different levels to investigate effects of intracellular redox status on secondary metabolism. NOX expression reduced the intracellular [NADH]/[NAD+] ratios significantly, although with a strong constitutive promoter NOX function was limited due to the shortage of oxygen. We demonstrated the negative correlation between [NADH]/[NAD+] ratios and biosynthesis of erythromycin in S.erythraea, but a positive correlation between the redox ratios and pigment production as well. We furthermore completed next-generation RNA sequencing of E3 and two NOX-expression strains. The transcription results showed that transfer processes of carbohydrates, DNA and chemical groups were altered resulting in metabolic shifts to supply more NADH for NOX fully functioning. Additionally, redox status affected transcription of several genes by allosteric effects on their transcription initiation. Specifically, transcriptional analysis along with enzymatic assay suggested that redox status influenced biosynthesis of erythromycin indirectly by allosteric effects on biosynthesis of the secondary messenger, c-di-GMP. The present work provides a basis for future cofactor manipulation in S.erythraea for further improvement of erythromycin production.
2020-08-04 | GSE144067 | GEO
Project description:IFNg is an essential and pleiotropic activator of monocytes, but little is known about the changes in cellular metabolism required for IFNg-induced activation. We sought to characterize and elucidate the mechanisms by which IFNg reprograms monocyte metabolism to support its immunologic activities. Monocytes from healthy controls and patients with gain-of-function mutations in STAT1 (STAT1 GOF), or loss-of-function mutations in mitochondrial complex I (Leigh syndrome) and NADPH oxidase (chronic granulomatous disease, CGD) were metabolically phenotyped. We found that IFNg increased oxygen consumption rates (OCR), indicative of reactive oxygen species generation by both mitochondria and NADPH oxidase. Transcriptional profiling of human monocyte derived macrophages revealed that this oxidative phenotype was driven by an IFNg-induced reprogramming of NAD+ metabolism, which is dependent on nicotinamide phosphoribosyltransferase (NAMPT)-mediated NAD+ salvage to generate NADH and NADPH for oxidation by mitochondrial complex I and NADPH oxidase, respectively. Monocytes from patients with STAT1 GOF demonstrated higher than normal OCR, while monocytes from Leigh syndrome and CGD patients demonstrated reduced OCR. Chemical inhibition of NAMPT completely abrogated the IFNg-induced oxygen consumption, comparable to levels observed in CGD patients. These data identify an IFNg-induced, NAMPT-dependent, NAD+ salvage pathway that is critical for IFNg activation of human monocytes.
2021-12-31 | GSE176562 | GEO
Project description:Perturbed metabolism of ammonia, an endogenous cytotoxic molecule, causes mitochondrial dysfunction with decreased nicotinamide adenine dinucleotide (NAD+) in skeletal muscle. Consistent with our previous report of enrichment of NAD metabolism and sirtuin pathways during hyperammonemia, NAD+-dependent Sirtuin3 (Sirt3) expression and deacetylase activity weredecreased with increased muscle protein acetylation in murine and human skeletal muscle/myotubes. Acetylomics and cell fractions showed hyperammonemia-induced hyperacetylation of critical mitochondrial and signaling molecules. Overexpression of mitochondrial targeted Lactobacillus brevis NADH oxidase (MitoLbNOX) reversed ammonia-induced oxidative dysfunction, electron transport chain (ETC) supercomplex disassembly, lower ATP content, NAD+, and redox ratio (NAD+/NADH). Protein hyperacetylation, post-mitotic senescence and lower mitochondrial sirtuin (Sirt3) expressionduring hyperammonemia were also reversed by MitoLbNOX. Sirt3 overexpression alone did not reverse ammonia-induced redox or mitochondrial dysfunction but reversed hyperacetylation and senescence. These data show that targeting redox ratio, rather than Sirt3, more consistently restores mitochondrial homeostasis and protein acetylation during hyperammonemia.
2023-10-24 | PXD033430 | Pride
Project description:This model by Jana Wolf et al. 2001 is the first mechanistic model of respiratory oscillations in Saccharomyces cerevisae. It is based on the assumption that feedback inhibition of cysteine on the sulfate transporters leads to oscillations in this pathway and causes oscillations in respiratory activity via inhibition of cytochrome c oxidase by hydrogen disulfide. The model is qualitative/semi-quantitative and reproduces the respiratory oscillation pattern quite well. It is based on very coarse-grained representations of the mitochondrial tricarboxylic acid cycle and the mitochondrial electron transport chain (oxidative phosphorylation). The sulfate assimilatory pathways also contains some significant simplifcations.
The model corresponds to Fig. 2B of the paper, with a slight phase shift of the oscillations. No initial conditions were given in the paper, and thus they were chosen arbitrarily in a range that lies within the basin of attraction of the limit cycle oscillations. Species IDs correspond to IDs used by the authors, while SBML names are more common abbreviations.
Caveats:
1) Equilibrated transport:
The model assumes fast equilibration between mitochondria and cytoplasm for the metabolites NADH, NAD+, H2S and Acetyl-CoA.
2) Cytosolic mass conservation ATP/ADP:
The model uses mass conservation for cytosolic adenosine nucleotides with is however not encoded in the stoichiometry, but is implied by the lumped reaction v4. This reaction combines the enzymatic reactions of phosphoadenylyl-sulfate reductase (thioredoxin) (yeast protein Met16p, EC 1.8.4.8) and sulfite reductase (NADPH) (subunits Met5p and Met10p, EC 1.8.1.2). EC 1.8.4.8 also has adenosine-3',5'-bismonophosphate (PAP, not to confuse with ID pap in this model, standing for PAPS) as a product. PAP is the substrate for enzyme 3'(2'),5'-bisphosphate nucleotidase (Met22p, EC:3.1.3.7) which would revover AMP (and Pi). Then AMP can be assumed to be equilibrated with ATP and ADP via adenylate kinase, as often used in metabolic models. This AMP production is implied in the mass conservation for cytosolic adenosine phosphates. Accounting for these reactions explicitly does not change the dynamics of the model significantly. An according version can be obtained from the SBML creator (Rainer Machne, mailto:raim@tbi.univie.ac.at).
3) Redox balance:
The enzyme sulfite reductase (NADPH) (subunits Met5p and Met10p, EC 1.8.1.2, part of reaction v4) actually uses NADPH, and the authors assume equilibration of NADH and NADPH. But actually S. cerevisiae specifically is missing the according enzyme transhydrogenase (EC 1.6.1.1 or EC 1.6.1.2). EC 1.8.4.8 also oxidizes thioredoxin and would actually require an additional NADPH for thioredoxin recovery (reduction). This would slightly affect the redox balance of the model.
4) Energy balance:
Reaction v7 lumps NAD-dependent alcohol dehydrogenase (EC 1.1.1.1), aldehyde dehydrogenase (NAD+) (EC 1.2.1.3) and acetyl-CoA synthase (EC 6.2.1.1). The latter reaction would actually consume ATP as a co-factor, producing AMP+PPi, and this is not included in the model. This would slightly bias the model's energy balance.
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To cite BioModels Database, please use: Li C, Donizelli M, Rodriguez N, Dharuri H, Endler L, Chelliah V, Li L, He E, Henry A, Stefan MI, Snoep JL, Hucka M, Le Novère N, Laibe C (2010) BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. BMC Syst Biol., 4:92.
2007-01-23 | BIOMD0000000090 | BioModels
Project description:PDAC cells acquire metabolic changes that augment NADPH production and cytosolic redox homeostasis. Here we show that high NADPH levels drive activity of NADPH oxidase 4 (NOX4) expressed in the endoplasmic reticulum (ER) membrane. NOX4 produces H2O2 metabolized by Peroxiredoxin 4 (PRDX4) in the ER lumen. Using functional genomics and subsequent in vitro and in vivo validations, we find that PDAC cell lines with high NADPH levels are dependent on PRDX4 for their growth and survival. PRDX4 addiction is associated with increased reactive oxygen species, a DNA-PKcs-governed DNA damage response and radiosensitivity, which can be rescued by depletion of NOX4 or NADPH. As such, this study has identified NOX4 as a protein which paradoxically converts the reducing power of the cytosol to an ER-specific oxidative stress vulnerability in PDAC that may be therapeutically exploited by targeting PRDX4.
2021-05-25 | GSE166165 | GEO
Project description:To dissect the metabolic state of B-ALL cells, we have developed a genetically encoded fluorescent sensor (SoNar) for tracking cytosolic NADH and NAD+ redox states and constructed the transgenic mouse. Based on the NADH/NAD+ ratio, we have sorted SoNar-high and SoNar-low B-ALL cells to employ whole genome microarray expression profiling as a discovery platform to identify genes with the potential to regulate the metabolism of B-ALL cells.
2018-02-06 | GSE110111 | GEO