The Global Repressor SugR Controls Expression of Genes of Glycolysis and of the l-Lactate Dehydrogenase LdhA in Corynebacterium glutamicum

ABSTRACT The transcriptional regulator SugR from Corynebacterium glutamicum represses genes of the phosphoenolpyruvate-dependent phosphotransferase system (PTS). Growth experiments revealed that the overexpression of sugR not only perturbed the growth of C. glutamicum on the PTS sugars glucose, fructose, and sucrose but also led to a significant growth inhibition on ribose, which is not taken up via the PTS. Chromatin immunoprecipitation combined with DNA microarray analysis and gel retardation experiments were performed to identify further target genes of SugR. Gel retardation analysis confirmed that SugR bound to the promoter regions of genes of the glycolytic enzymes 6-phosphofructokinase (pfkA), fructose-1,6-bisphosphate aldolase (fba), enolase (eno), pyruvate kinase (pyk), and NAD-dependent l-lactate dehydrogenase (ldhA). The deletion of sugR resulted in increased mRNA levels of eno, pyk, and ldhA in acetate medium. Enzyme activity measurements revealed that SugR-mediated repression affects the activities of PfkA, Fba, and LdhA in vivo. As the deletion of sugR led to increased LdhA activity under aerobic and under oxygen deprivation conditions, l-lactate production by C. glutamicum was determined. The overexpression of sugR reduced l-lactate production by about 25%, and sugR deletion increased l-lactate formation under oxygen deprivation conditions by threefold. Thus, SugR functions as a global repressor of genes of the PTS, glycolysis, and fermentative l-lactate dehydrogenase in C. glutamicum.

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The ldhA Gene Encoding Fermentative L-Lactate Dehydrogenase in Corynebacterium glutamicum Is Positively Regulated by the Global Regulator GlxR

Microorganisms ◽

10.3390/microorganisms9030550 ◽

2021 ◽

Vol 9 (3) ◽

pp. 550

Author(s):

Koichi Toyoda ◽

Masayuki Inui

Keyword(s):

Lactate Dehydrogenase ◽

Binding Site ◽

Corynebacterium Glutamicum ◽

Lactate Production ◽

Exponential Phase ◽

Aerobic Bacterium ◽

Global Regulator ◽

Gene Encoding ◽

Fermentation Products ◽

Ldha Gene

Bacterial metabolism shifts from aerobic respiration to fermentation at the transition from exponential to stationary growth phases in response to limited oxygen availability. Corynebacterium glutamicum, a Gram-positive, facultative aerobic bacterium used for industrial amino acid production, excretes L-lactate, acetate, and succinate as fermentation products. The ldhA gene encoding L-lactate dehydrogenase is solely responsible for L-lactate production. Its expression is repressed at the exponential phase and prominently induced at the transition phase. ldhA is transcriptionally repressed by the sugar-phosphate-responsive regulator SugR and L-lactate-responsive regulator LldR. Although ldhA expression is derepressed even at the exponential phase in the sugR and lldR double deletion mutant, a further increase in its expression is still observed at the stationary phase, implicating the action of additional transcription regulators. In this study, involvement of the cAMP receptor protein-type global regulator GlxR in the regulation of ldhA expression was investigated. The GlxR-binding site found in the ldhA promoter was modified to inhibit or enhance binding of GlxR. The ldhA promoter activity and expression of ldhA were altered in proportion to the binding affinity of GlxR. Similarly, L-lactate production was also affected by the binding site modification. Thus, GlxR was demonstrated to act as a transcriptional activator of ldhA.

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TOP1MT deficiency promotes GC invasion and migration via the enhancements of LDHA expression and aerobic glycolysis

Endocrine Related Cancer ◽

10.1530/erc-17-0058 ◽

2017 ◽

Vol 24 (11) ◽

pp. 565-578 ◽

Cited By ~ 7

Author(s):

Hongqiang Wang ◽

Rui Zhou ◽

Li Sun ◽

Jianling Xia ◽

Xuchun Yang ◽

...

Keyword(s):

Cancer Progression ◽

Topoisomerase I ◽

Target Genes ◽

Aerobic Glycolysis ◽

Lactate Production ◽

Migration And Invasion ◽

Glucose Transporter 1 ◽

Mesenchymal Transition

Aerobic glycolysis plays an important role in cancer progression. New target genes regulating cancer aerobic glycolysis must be explored to improve patient prognosis. Mitochondrial topoisomerase I (TOP1MT) deficiency suppresses glucose oxidative metabolism but enhances glycolysis in normal cells. Here, we examined the role of TOP1MT in gastric cancer (GC) and attempted to determine the underlying mechanism. Using in vitro and in vivo experiments and analyzing the clinicopathological characteristics of patients with GC, we found that TOP1MT expression was lower in GC samples than in adjacent nonmalignant tissues. TOP1MT knockdown significantly promoted GC migration and invasion in vitro and in vivo. Importantly, TOP1MT silencing increased glucose consumption, lactate production, glucose transporter 1 expression and the epithelial-mesenchymal transition (EMT) in GC. Additionally, regulation of glucose metabolism induced by TOP1MT was significantly associated with lactate dehydrogenase A (LDHA) expression. A retrospective analysis of clinical data from 295 patients with GC demonstrated that low TOP1MT expression was associated with lymph node metastasis, recurrence and high mortality rates. TOP1MT deficiency enhanced glucose aerobic glycolysis by stimulating LDHA to promote GC progression.

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Circular RNA CDR1as Exerts Oncogenic Properties Partially through Regulating MicroRNA 641 in Cholangiocarcinoma

Molecular and Cellular Biology ◽

10.1128/mcb.00042-20 ◽

2020 ◽

Vol 40 (15) ◽

Cited By ~ 1

Author(s):

Dingyang Li ◽

Zhe Tang ◽

Zhiqiang Gao ◽

Pengcheng Shen ◽

Zhaochen Liu ◽

...

Keyword(s):

Cell Proliferation ◽

Target Genes ◽

Circular Rna ◽

Tumor Xenograft ◽

Mrna Levels ◽

Cell Behaviors ◽

Xenograft Growth ◽

Tumor Xenograft Growth

ABSTRACT It has been found that the circular RNA (circRNA) CDR1as is upregulated in cholangiocarcinoma (CCA) tissues. In this study, we tried to explore the roles of CDR1as in CCA. CDR1as was overexpressed or knocked down in human CCA cells to assess the effects of CDR1as on cell behaviors and tumor xenograft growth. In vitro, the CDR1as level was significantly increased in CCA cell lines. The results showed that CDR1as promoted the cell proliferation, migration, invasion, and activation of the AKT3/mTOR pathway in CCA cells. Moreover, miR-641, a predicted target microRNA (miRNA) of CDR1as, could partially reverse the effects of CDR1as on cell behaviors in CCA cells. Furthermore, CDR1as improved tumor xenograft growth, and it could be attenuated by miR-641 in vivo. Additionally, CDR1as expression was inversely correlated with miR-641 in CCA cells, and miR-641 could directly bind with CDR1as and its target genes, the AKT3 and mTOR genes. Mechanistically, CDR1as could bind with miR-641 and accelerate miR-641 degradation, which possibly leads to the upregulation of the relative mRNA levels of AKT3 and mTOR in RBE cells. In conclusion, our findings indicated that CDR1as might exert oncogenic properties, at least partially, by regulating miR-641 in CCA. CDR1as and miR-641 could be considered therapeutic targets for CCA.

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Astaxanthin Treatment Induces Maturation and Functional Change of Myeloid-Derived Suppressor Cells in Tumor-Bearing Mice

Antioxidants ◽

10.3390/antiox9040350 ◽

2020 ◽

Vol 9 (4) ◽

pp. 350

Author(s):

Seong Mun Jeong ◽

Yeon-Jeong Kim

Keyword(s):

Mhc Class Ii ◽

Target Genes ◽

Suppressor Cells ◽

Functional Change ◽

Related Factor ◽

Mrna Levels ◽

Myeloid Derived Suppressor Cells ◽

Antitumor Effects

Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells which accumulate in stress conditions such as infection and tumor. Astaxanthin (ATX) is a well-known antioxidant agent and has a little toxicity. It has been reported that ATX treatment induces antitumor effects via regulation of cell signaling pathways, including nuclear factor erythroid-derived 2-related factor 2 (Nrf2) signaling. In the present study, we hypothesized that treatment with ATX might induce maturation of MDSCs and modulate their immunosuppressive activity. Both in vivo and in vitro treatment with ATX resulted in up-regulation of surface markers such as CD80, MHC class II, and CD11c on both polymorphonuclear (PMN)-MDSCs and mononuclear (Mo)-MDSCs. Expression levels of functional mediators involved in immune suppression were significantly reduced, whereas mRNA levels of Nrf2 target genes were increased in ATX-treated MDSCs. In addition, ATX was found to have antioxidant activity reducing reactive oxygen species level in MDSCs. Finally, ATX-treated MDSCs were immunogenic enough to induce cytotoxic T lymphocyte response and contributed to the inhibition of tumor growth. This demonstrates the role of ATX as a regulator of the immunosuppressive tumor environment through induction of differentiation and functional conversion of MDSCs.

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Characterization of a Corynebacterium glutamicum Lactate Utilization Operon Induced during Temperature-Triggered Glutamate Production

Applied and Environmental Microbiology ◽

10.1128/aem.71.10.5920-5928.2005 ◽

2005 ◽

Vol 71 (10) ◽

pp. 5920-5928 ◽

Cited By ~ 132

Author(s):

Corinna Stansen ◽

Davin Uy ◽

Stephane Delaunay ◽

Lothar Eggeling ◽

Jean-Louis Goergen ◽

...

Keyword(s):

Lactate Dehydrogenase ◽

Carbon Source ◽

Corynebacterium Glutamicum ◽

Specific Activity ◽

Temperature Shift ◽

Pcr Analysis ◽

Mrna Levels ◽

Reverse Transcription Pcr ◽

Glutamate Production ◽

Lactate Utilization

ABSTRACT Gene expression changes of glutamate-producing Corynebacterium glutamicum were identified in transcriptome comparisons by DNA microarray analysis. During glutamate production induced by a temperature shift, C. glutamicum strain 2262 showed significantly higher mRNA levels of the NCgl2816 and NCgl2817 genes than its non-glutamate-producing derivative 2262NP. Reverse transcription-PCR analysis showed that the two genes together constitute an operon. NCgl2816 putatively codes for a lactate permease, while NCgl2817 was demonstrated to encode quinone-dependent l-lactate dehydrogenase, which was named LldD. C. glutamicum LldD displayed Michaelis-Menten kinetics for the substrate l-lactate with a Km of about 0.51 mM. The specific activity of LldD was about 10-fold higher during growth on l-lactate or on an l-lactate-glucose mixture than during growth on glucose, d-lactate, or pyruvate, while the specific activity of quinone-dependent d-lactate dehydrogenase differed little with the carbon source. RNA levels of NCgl2816 and lldD were about 18-fold higher during growth on l-lactate than on pyruvate. Disruption of the NCgl2816-lldD operon resulted in loss of the ability to utilize l-lactate as the sole carbon source. Expression of lldD restored l-lactate utilization, indicating that the function of the permease gene NCgl2816 is dispensable, while LldD is essential, for growth of C. glutamicum on l-lactate.

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Lactate Dehydrogenase Is the Key Enzyme for Pneumococcal Pyruvate Metabolism and Pneumococcal Survival in Blood

Infection and Immunity ◽

10.1128/iai.02005-14 ◽

2014 ◽

Vol 82 (12) ◽

pp. 5099-5109 ◽

Cited By ~ 28

Author(s):

Paula Gaspar ◽

Firas A. Y. Al-Bayati ◽

Peter W. Andrew ◽

Ana Rute Neves ◽

Hasan Yesilkaya

Keyword(s):

Lactate Dehydrogenase ◽

Lactate Production ◽

Virulence Gene ◽

Redox Balance ◽

Central Metabolism ◽

Content Type ◽

Virulence Gene Expression ◽

Key Enzyme

ABSTRACTStreptococcus pneumoniaeis a fermentative microorganism and causes serious diseases in humans, including otitis media, bacteremia, meningitis, and pneumonia. However, the mechanisms enabling pneumococcal survival in the host and causing disease in different tissues are incompletely understood. The available evidence indicates a strong link between the central metabolism and pneumococcal virulence. To further our knowledge on pneumococcal virulence, we investigated the role of lactate dehydrogenase (LDH), which converts pyruvate to lactate and is an essential enzyme for redox balance, in the pneumococcal central metabolism and virulence using an isogenicldhmutant. Loss of LDH led to a dramatic reduction of the growth rate, pinpointing the key role of this enzyme in fermentative metabolism. The pattern of end products was altered, and lactate production was totally blocked. The fermentation profile was confirmed byin vivonuclear magnetic resonance (NMR) measurements of glucose metabolism in nongrowing cell suspensions of theldhmutant. In this strain, a bottleneck in the fermentative steps is evident from the accumulation of pyruvate, revealing LDH as the most efficient enzyme in pyruvate conversion. An increase in ethanol production was also observed, indicating that in the absence of LDH the redox balance is maintained through alcohol dehydrogenase activity. We also found that the absence of LDH renders the pneumococci avirulent after intravenous infection and leads to a significant reduction in virulence in a model of pneumonia that develops after intranasal infection, likely due to a decrease in energy generation and virulence gene expression.

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Foxa1 and Foxa2 Regulate α-Cell Differentiation, Glucagon Biosynthesis, and Secretion

Endocrinology ◽

10.1210/en.2013-1843 ◽

2014 ◽

Vol 155 (10) ◽

pp. 3781-3792 ◽

Cited By ~ 22

Author(s):

Mounia Heddad Masson ◽

Caroline Poisson ◽

Audrey Guérardel ◽

Aline Mamin ◽

Jacques Philippe ◽

...

Keyword(s):

Gene Expression ◽

Cell Differentiation ◽

Target Genes ◽

Adult Mouse ◽

Glucagon Secretion ◽

Mrna Levels ◽

Forkhead Box ◽

Interfering Rna

Abstract The Forkhead box A transcription factors are major regulators of glucose homeostasis. They show both distinct and redundant roles during pancreas development and in adult mouse β-cells. In vivo ablation studies have revealed critical implications of Foxa1 on glucagon biosynthesis and requirement of Foxa2 in α-cell terminal differentiation. In order to examine the respective role of these factors in mature α-cells, we used small interfering RNA (siRNA) directed against Foxa1 and Foxa2 in rat primary pancreatic α-cells and rodent α-cell lines leading to marked decreases in Foxa1 and Foxa2 mRNA levels and proteins. Both Foxa1 and Foxa2 control glucagon gene expression specifically through the G2 element. Although we found that Foxa2 controls the expression of the glucagon, MafB, Pou3f4, Pcsk2, Nkx2.2, Kir6.2, and Sur1 genes, Foxa1 only regulates glucagon gene expression. Interestingly, the Isl1 and Gipr genes were not controlled by either Foxa1 or Foxa2 alone but by their combination. Foxa1 and Foxa2 directly activate and bind the promoter region the Nkx2.2, Kir6.2 and Sur1, Gipr, Isl1, and Pou3f4 genes. We also demonstrated that glucagon secretion is affected by the combined effects of Foxa1 and Foxa2 but not by either one alone. Our results indicate that Foxa1 and Foxa2 control glucagon biosynthesis and secretion as well as α-cell differentiation with both common and unique target genes.

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Vegf regulates embryonic erythroid development through Gata1 modulation

Blood ◽

10.1182/blood-2010-01-264143 ◽

2010 ◽

Vol 116 (12) ◽

pp. 2141-2151 ◽

Cited By ~ 17

Author(s):

Benjamin Drogat ◽

Joanna Kalucka ◽

Laura Gutiérrez ◽

Hamida Hammad ◽

Steven Goossens ◽

...

Keyword(s):

Target Genes ◽

Erythroid Differentiation ◽

Mrna Levels ◽

Loss Of Function ◽

Erythroid Progenitor ◽

Expression Levels ◽

Conditional Deletion ◽

Differentiation Block ◽

Erythroid Development

Abstract To determine the role of vascular endothelial growth factor (Vegf) in embryonic erythroid development we have deleted or overexpressed Vegf specifically in the erythroid lineage using the EpoR-iCre transgenic line in combination with Cre/loxP conditional gain and loss of function Vegf alleles. ROSA26 promoter-based expression of the Vegf164 isoform in the early erythroid lineage resulted in a differentiation block of primitive erythroid progenitor (EryP) development and a partial block in definitive erythropoiesis between the erythroid burst-forming unit and erythroid colony-forming unit stages. Decreased mRNA expression levels of the key erythroid transcription factor Gata1 were causally linked to this phenotype. Conditional deletion of Vegf within the erythroid lineage was associated with increased Gata1 levels and increased erythroid differentiation. Expression of a ROSA26-based GATA2 transgene rescued Gata1 mRNA levels and target genes and restored erythroid differentiation in our Vegf gain of function model. These results demonstrate that Vegf modulates Gata1 expression levels in vivo and provides new molecular insight into Vegf's ability to modulate erythropoiesis.

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Intestinal perfusion induces rapid activation of immediate-early genes in weaning rats

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.2001.281.4.r1274 ◽

2001 ◽

Vol 281 (4) ◽

pp. R1274-R1282 ◽

Cited By ~ 8

Author(s):

Lan Jiang ◽

Heather Lawsky ◽

Relicardo M. Coloso ◽

Mary A. Dudley ◽

Ronaldo P. Ferraris

Keyword(s):

Mrna Expression ◽

Target Genes ◽

De Novo ◽

Immediate Early Genes ◽

Regulatory Elements ◽

Intestinal Perfusion ◽

Immediate Early ◽

Mrna Levels ◽

Early Genes

C- fos and c- jun are immediate-early genes (IEGs) that are rapidly expressed after a variety of stimuli. Products of these genes subsequently bind to DNA regulatory elements of target genes to modulate their transcription. In rat small intestine, IEG mRNA expression increases dramatically after refeeding following a 48-h fast. We used an in vivo intestinal perfusion model to test the hypothesis that metabolism of absorbed nutrients stimulates the expression of IEGs. Compared with those of unperfused intestines, IEG mRNA levels increased up to 11 times after intestinal perfusion for 0.3–4 h with Ringer solutions containing high (100 mM) fructose (HF), glucose (HG), or mannitol (HM). Abundance of mRNA returned to preperfusion levels after 8 h. Levels of c- fos and c- jun mRNA and proteins were modest and evenly distributed among enterocytes lining the villi of unperfused intestines. HF and HM perfusion markedly enhanced IEG mRNA expression along the entire villus axis. The perfusion-induced increase in IEG expression was inhibited by actinomycin-D. Luminal perfusion induces transient but dramatic increases in c- fos and c- jun expression in villus enterocytes. Induction does not require metabolizable or absorbable nutrients but may involve de novo gene transcription in cells along the villus.

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PPAR-alpha activation as a preconditioning-like intervention in rats in vivo confers myocardial protection against acute ischaemia–reperfusion injury: involvement of PI3K–Akt

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y2012-052 ◽

2012 ◽

Vol 90 (8) ◽

pp. 1135-1144 ◽

Cited By ~ 34

Author(s):

Táňa Ravingerová ◽

Slávka Čarnická ◽

Martina Nemčeková ◽

Veronika Ledvényiová ◽

Adriana Adameová ◽

...

Keyword(s):

Target Genes ◽

Left Ventricular ◽

Metabolic Effects ◽

Peroxisome Proliferator ◽

Mrna Levels ◽

Akt Inhibitor ◽

Ischaemia Reperfusion Injury ◽

Acute Ischaemia ◽

Ischaemia Reperfusion

Peroxisome proliferator-activated receptors (PPAR) regulate the expression of genes involved in lipid metabolism, energy production, and inflammation. Their role in ischaemia–reperfusion (I/R) is less clear, although research indicates involvement of PPARs in some forms of preconditioning. This study aimed to explore the effects of PPAR-α activation on the I/R injury and potential cardioprotective downstream mechanisms involved. Langendorff-perfused hearts of rats pretreated with the selective PPAR-α agonist WY-14643 (WY, pirinixic acid; 3 mg·(kg body mass)·day–1; 5 days) were subjected to 30 min ischaemia – 2 h reperfusion with or without the phosphatidylinositol 3-kinase (PI3K)–Akt inhibitor wortmannin for the evaluation of functional (left ventricular developed pressure, LVDP) recovery, infarct size (IS), and reperfusion-induced arrhythmias. A 2-fold increase in baseline PPAR-α mRNA levels (qPCR) in the WY-treated group and higher post-I/R PPAR-α levels compared with those in untreated controls were accompanied by similar changes in the expression of PPAR-α target genes PDK4 and mCPT-1, regulating glucose and fatty acid metabolism, and by enhanced Akt phosphorylation. Post-ischaemic LVDP restoration in WY-treated hearts reached 60% ± 9% of the pre-ischaemic values compared with 24% ± 3% in the control hearts (P < 0.05), coupled with reduced IS and incidence of ventricular fibrillation that was blunted by wortmannin. Results indicate that PPAR-α up-regulation may confer preconditioning-like protection via metabolic effects. Downstream mechanisms of PPAR-α-mediated cardioprotection may involve PI3K–Akt activation.

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