Dual effect: High NADH levels contribute to efflux-mediated antibiotic resistance but drive ROS lethality
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PROVIDER: PRJNA780411 | ENA |
REPOSITORIES: ENA
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Project description:In light of the antibiotic crisis, emerging strategies to sensitize bacteria to available antibiotics should be explored. Several studies on the mechanisms of killing suggest that bactericidal antibiotic activity is enforced through the generation of reactive oxygen species (ROS lethality hypothesis). Here, we artificially manipulated the redox homeostasis of the model opportunistic pathogen Pseudomonas aeruginosa using specific enzymes that catalyze either the formation or oxidation of NADH. Increased NADH levels led to the activation of antibiotic efflux pumps and high levels of antibiotic resistance. However, higher NADH levels also resulted in increased intracellular ROS and amplified antibiotic killing. Our results demonstrate that growth inhibition and killing activity are mediated via different mechanisms. Furthermore, the profound changes in bioenergetics produced low virulence phenotypes characterized by reduced inter-bacterial signaling controlled pathogenicity traits. Our results pave the way for a more effective infection resolution and add an anti-virulence strategy to maximize chances to combat devastating P. aeruginosa infections while reducing the overall use of antibiotics.
2021-11-17 | GSE188801 | GEO
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| S-EPMC8764520 | biostudies-literature
Project description:Efflux pumps of the resistance-nodulation-division (RND) superfamily, particularly the AcrAB-TolC and MexAB-OprM, besides mediating intrinsic and acquired resistance, also intervene in bacterial pathogenicity. Inhibitors of such pumps could restore activities of antibiotics and curb bacterial virulence. Here, we identify pyrrole-based compounds that boost antibiotic activity in Escherichia coli and Pseudomonas aeruginosa by inhibiting their archetype RND transporters. The discovered efflux pump inhibitors (EPIs) inhibit the efflux of fluorescent probes, attenuate persister formation, and diminish resistant mutant development. Molecular docking and biophysical studies revealed that the EPIs bind to AcrB. EPIs also possess an anti-pathogenic potential and attenuate P. aeruginosa virulence in vivo. The excellent efficacy of the EPI-antibiotic combination was evidenced in animal lung infection and sepsis protection models. These findings indicate that EPIs discovered herein with no off-target effects and negligible toxicity are potential antibiotic adjuvants to address life-threatening bacterial infections.
2024-03-18 | GSE210309 | GEO
Project description:The objective of this comparison was to identify the impact of NADH on the transcriptome of Streptococcus pneumoniae D39. Transcriptome comparison of the D39 wild-type grown in chemically-defined medium (CDM) with 0 mg/ml NADH to 0.5 mg/ml NADH revealed elevated expression of various genes/operons (adhB1, fba, hemH, rex, gapN, nirC, pncB, gap, adhE, and adhB2) involved in the transport and biosynthesis of niacin. In this study, we investigated the transcriptomic response of Streptococcus pneumoniae D39 to NADH. Transcriptome comparison of the D39 wild-type grown in chemically-defined medium (CDM) with 0 mg/ml NADH to 0.5 mg/ml NADH revealed elevated expression of various genes/operons (adhB1, fba, hemH, rex, gapN, nirC, pncB, gap, adhE, and adhB2) involved in the transport and biosynthesis of niacin. Microarray results were further confirmed by β-galactosidase assays. Promoter-lacZ fusions assays and microarray studies showed that the transcriptional regulator, Rex acts as a transcriptional repressor of a number of genes/operons (adhB1, fba, hemH, rex, gapN, nirC, pncB, gap, adhE, and adhB2) involved in niacin uptake and biosynthesis in the presence of NADH. The putative operator site of Rex in the promoter regions of Rex-regulated genes is predicted and confirmed by promoter mutational experiments.
2018-06-01 | GSE94572 | GEO
Project description:Y box-binding protein 1 (Ybx1) is critical for embryogenesis and organogenesis. In zebrafish, we identify Ybx1 is predominantly expressed in the enterocytes of intestine in day5 larvae, whereas its immediately degradation driven by ubiquitination on day6. Here we show the maternal lethality with cardiac edema in ybx1-/- larvae, and postnatal larval lethality exhibited in ybx1-/- larvae within the death window from 10dpf to 20dpf. To study the underlying mechanisms for the ybx1-/- larvae partial lethality, we performed RNA-seq and experimental results showed the increased ROS might be the underlying cause for the postnatal lethality. By ascorbic acid treatment, we found ascorbic acid exposure prevented ybx1-/- larvae from postnatal lethality, while hydrogen peroxide aggravated ybx1-/- larvae postnatal lethality during the death window. By RNA-seq analysis, we also found significantly increased expressions of mmp9 and mmp13a in ybx1-/- larvae, and by inhibition of either MMP9 or MMP13a expression partially rescue the ybx1-/- postnatal lethality during the death window. Later, we further identify the intestinal impairs on 30 dpf and further deteriorated severe intestinal disorder in Ybx1 deficiency zebrafish. By exposure of ybx1-/- zebrafish for 14 days, we discover ascorbic acid partially mend the impaired intestine in ybx1-/-. In this study, we demonstrate that ybx1-/- larvae were ROS-susceptible, and the increased inflammation in ybx1-/- larvae intestine identified enables the ybx1-/- zebrafish as good model for studying of intestinal disease.
2020-12-15 | GSE134334 | 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: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:In mammals, circadian rhythms are entrained to the light cycle and drive daily oscillations in levels of NAD+ a co-substrate of the class III histone deacetylase SIRT1 that associates with clock transcription factors. While NAD+ also participates in redox reactions, the extent to which NAD(H) couples nutrient state with circadian transcriptional cycles remains unknown. Here we show that nocturnal animals subjected to time-restricted feeding of a calorie-restricted diet (TRF-CR) only during nighttime display reduced body temperature and elevated hepatic NADH during daytime. Genetic uncoupling of nutrient state from NADH redox state through transduction of the water-forming NADH oxidase from Lactobacillus brevis (LbNOX) increases daytime body temperature and blood and liver acyl-carnitines. LbNOX expression in TRF-CR mice induces oxidative gene networks controlled by BMAL1 and PPARa and suppresses amino acid catabolic pathways. Enzymatic analyses reveal that NADH inhibits SIRT1 in vitro, corresponding with reduced deacetylation of SIRT1 substrates during TRF-CR in vivo. Remarkably, Sirt1 liver nullizygous animals subjected to TRF-CR display persistent hypothermia even when NADH is oxidized by LbNOX. Our findings reveal that the hepatic NADH cycle links nutrient state to whole-body energetics through the rhythmic regulation of SIRT1.
2021-10-08 | GSE151281 | 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:To study the overabundance of reducing equivalents, termed reductive stress, specifically for NADH reductive stress, we introduce a soluble transhydrogenase from E. coli (EcSTH) as a novel genetically encoded tool to promote NADH overproduction
2023-09-01 | GSE232115 | GEO