scholarly journals Upregulation of COX4-2 via HIF-1α in Mitochondrial COX4-1 Deficiency

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 452
Author(s):  
Liza Douiev ◽  
Chaya Miller ◽  
Shmuel Ruppo ◽  
Hadar Benyamini ◽  
Bassam Abu-Libdeh ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Oxidative Phosphorylation ◽  
Nuclear Localization ◽  
Target Genes ◽  
Compensatory Mechanism ◽  
Terminal Electron Acceptor ◽  
Human Foreskin Fibroblasts ◽  
Mitochondrial Respiratory Complex ◽  
Mrna Transcripts ◽  
Oxphos System

Cytochrome-c-oxidase (COX) subunit 4 (COX4) plays important roles in the function, assembly and regulation of COX (mitochondrial respiratory complex 4), the terminal electron acceptor of the oxidative phosphorylation (OXPHOS) system. The principal COX4 isoform, COX4-1, is expressed in all tissues, whereas COX4-2 is mainly expressed in the lungs, or under hypoxia and other stress conditions. We have previously described a patient with a COX4-1 defect with a relatively mild presentation compared to other primary COX deficiencies, and hypothesized that this could be the result of a compensatory upregulation of COX4-2. To this end, COX4-1 was downregulated by shRNAs in human foreskin fibroblasts (HFF) and compared to the patient’s cells. COX4-1, COX4-2 and HIF-1α were detected by immunocytochemistry. The mRNA transcripts of both COX4 isoforms and HIF-1 target genes were quantified by RT-qPCR. COX activity and OXPHOS function were measured by enzymatic and oxygen consumption assays, respectively. Pathways were analyzed by CEL-Seq2 and by RT-qPCR. We demonstrated elevated COX4-2 levels in the COX4-1-deficient cells, with a concomitant HIF-1α stabilization, nuclear localization and upregulation of the hypoxia and glycolysis pathways. We suggest that COX4-2 and HIF-1α are upregulated also in normoxia as a compensatory mechanism in COX4-1 deficiency.

Early embryonic expression ofFGF4/6/9gene and its role in the induction of mesenchyme and notochord inCiona savignyiembryos

Development ◽  
2002 ◽  
Vol 129 (7) ◽  
pp. 1729-1738 ◽  
Author(s):  
Kaoru S. Imai ◽  
Nori Satoh ◽  
Yutaka Satou
Keyword(s):  
Cell Differentiation ◽  
Nuclear Localization ◽  
Target Genes ◽  
Muscle Cells ◽  
Cell Stage ◽  
Ciona Savignyi ◽  
Mesenchyme Cell ◽  
Notochord Cells ◽  
Mesenchyme Cells ◽  
Endodermal Cells

In early Ciona savignyi embryos, nuclear localization of β-catenin is the first step of endodermal cell specification, and triggers the activation of various target genes. A cDNA for Cs-FGF4/6/9, a gene activated downstream of β-catenin signaling, was isolated and shown to encode an FGF protein with features of both FGF4/6 and FGF9/20. The early embryonic expression of Cs-FGF4/6/9 was transient and the transcript was seen in endodermal cells at the 16- and 32-cell stages, in notochord and muscle cells at the 64-cell stage, and in nerve cord and muscle cells at the 110-cell stage; the gene was then expressed again in cells of the nervous system after neurulation. When the gene function was suppressed with a specific antisense morpholino oligo, the differentiation of mesenchyme cells was completely blocked, and the fate of presumptive mesenchyme cells appeared to change into that of muscle cells. The inhibition of mesenchyme differentiation was abrogated by coinjection of the morpholino oligo and synthetic Cs-FGF4/6/9 mRNA. Downregulation of β-catenin nuclear localization resulted in the absence of mesenchyme cell differentiation due to failure of the formation of signal-producing endodermal cells. Injection of synthetic Cs-FGF4/6/9 mRNA in β-catenin-downregulated embryos evoked mesenchyme cell differentiation. These results strongly suggest that Cs-FGF4/6/9 produced by endodermal cells acts an inductive signal for the differentiation of mesenchyme cells. On the other hand, the role of Cs-FGF4/6/9 in the induction of notochord cells is partial; the initial process of the induction was inhibited by Cs-FGF4/6/9 morpholino oligo, but notochord-specific genes were expressed later to form a partial notochord.

scholarly journals XBP-1 Regulates a Subset of Endoplasmic Reticulum Resident Chaperone Genes in the Unfolded Protein Response

2003 ◽  
Vol 23 (21) ◽  
pp. 7448-7459 ◽  
Author(s):  
Ann-Hwee Lee ◽  
Neal N. Iwakoshi ◽  
Laurie H. Glimcher
Keyword(s):  
Endoplasmic Reticulum ◽  
Unfolded Protein Response ◽  
Target Genes ◽  
Gene Profiling ◽  
Minor Role ◽  
Compensatory Mechanism ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
A Minor ◽  
Protein Response

ABSTRACT The mammalian unfolded protein response (UPR) protects the cell against the stress of misfolded proteins in the endoplasmic reticulum (ER). We have investigated here the contribution of the UPR transcription factors XBP-1, ATF6α, and ATF6β to UPR target gene expression. Gene profiling of cell lines lacking these factors yielded several XBP-1-dependent UPR target genes, all of which appear to act in the ER. These included the DnaJ/Hsp40-like genes, p58IPK, ERdj4, and HEDJ, as well as EDEM, protein disulfide isomerase-P5, and ribosome-associated membrane protein 4 (RAMP4), whereas expression of BiP was only modestly dependent on XBP-1. Surprisingly, given previous reports that enforced expression of ATF6α induced a subset of UPR target genes, cells deficient in ATF6α, ATF6β, or both had minimal defects in upregulating UPR target genes by gene profiling analysis, suggesting the presence of compensatory mechanism(s) for ATF6 in the UPR. Since cells lacking both XBP-1 and ATF6α had significantly impaired induction of select UPR target genes and ERSE reporter activation, XBP-1 and ATF6α may serve partially redundant functions. No UPR target genes that required ATF6β were identified, nor, in contrast to XBP-1 and ATF6α, did the activity of the UPRE or ERSE promoters require ATF6β, suggesting a minor role for it during the UPR. Collectively, these results suggest that the IRE1/XBP-1 pathway is required for efficient protein folding, maturation, and degradation in the ER and imply the existence of subsets of UPR target genes as defined by their dependence on XBP-1. Further, our observations suggest the existence of additional, as-yet-unknown, key regulators of the UPR.

scholarly journals Oxidative Phosphorylation-Dependent and -Independent Oxygen Consumption by Individual Preimplantation Mouse Embryos1

2000 ◽  
Vol 62 (6) ◽  
pp. 1866-1874 ◽  
Author(s):  
James R. Trimarchi ◽  
Lin Liu ◽  
D. Marshall Porterfield ◽  
Peter J.S. Smith ◽  
David L. Keefe
Keyword(s):  
Oxygen Consumption ◽  
Oxidative Phosphorylation ◽  
Preimplantation Mouse

scholarly journals Mitochondrial Spare Reserve Capacity : A New Predictive Metabolic Biomarker for Aggressiveness of Acute Myeloid Leukemia

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 7-7
Author(s):  
Quentin Fovez ◽  
Bruno Quesnel ◽  
William Laine ◽  
Raeeka Khamari ◽  
Celine Berthon ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Oxygen Consumption ◽  
Oxidative Phosphorylation ◽  
Mutation Rate ◽  
Myeloid Leukemia ◽  
Leukemic Cells ◽  
Reserve Capacity ◽  
Glycolytic Activity ◽  
Acute Myeloid

Introduction The persistence of leukemic cells after treatment limits the effectiveness of anticancer drugs and is the cause of relapse in patients with acute myeloid leukemia (AML). After exposure to chemotherapeutic drugs, the survival of leukemic cells is mainly supported by mitochondrial energy metabolism. Several preclinical studies have shown that the combination of mitochondrial oxidative phosphorylation inhibitors with various anticancer treatments constitutes an effective therapeutic combination in vitro to eradicate the surviving leukemic cells. Evaluating the mitochondrial bioenergetic activity of blasts from AML patients could therefore provide predictive information on treatment response. The basal oxygen consumption of cells varies according to hematopoietic differentiation and depends on the energy needs in the in vitro condition of measurement. But it is necessary to treat the cells with uncoupling agents (eg FCCP) to assess the maximum activity that the respiratory chain could reach to respond to energy stress. Then, the switch from a basal level of oxygen consumption to a maximum level defines the mitochondrial spare reserve capacity (SRC). In this study, we propose to determine whether spare reserve capacity of blasts is a potential biomarker of AML aggressiveness in patients and to characterize the biochemical processes involved in the control of SRC in leukemic cells. Results Using the XFe24 Seahorse fluorometric oximeter, we first determined the mitochondrial oxygen consumption and glycolytic activity in hematopoietic cells (monocytes, lymphocytes, dendritic cells) of healthy donors, in AML patient blasts at diagnosis or at relapse and in AML cell lines (HL-60, MOLM-13, THP-1, KG1, OCI-AML3, MV-4-11, U-937). All measures have been assessed from freshly collected samples of peripheral blood and of bone marrow. As expected, AMLs are characterized by low oxidative phosphorylation activity compared to normal hematopoietic cells. From all the OXPHOS values obtained we defined a SRC threshold above which the SRC is considered high. This threshold has been set at a capacity to increase basal respiration by 250%. From patients blasts, we have therefore defined two groups characterized by high (n=14) or low (n=21) mitochondrial spare reserve capacity. Blasts with high SRC exhibit high glycolytic activity suggesting a link between spare reserve capacity and glucose metabolism. Using U-13C6 glucose and pharmacological inhibitors, we have demonstrated that the utilization of the mitochondrial spare reserve capacity of leukemic cells is supported through glycolysis and that mitochondrial oxidation of pyruvate is a key element for SRC recruitment. Mitochondrial pyruvate carrier inhibitors (as UK-5099) or gene silencing of BRP44 abolish the SRC of leukemic cells highlighting the importance of pyruvate oxidation to increase oxygen consumption. Since high mutation rate is recognized as an unfavorable prognostic factor in AML, we have also sequenced 45 commonly genes mutated in AMLs characterized by high or low SRC blasts. Interestingly, DNA sequencing analysis showed that AML with low SRC blasts have a higher mutation rate than high SRC blasts and also exhibited exclusive mutations such as ASXL1 (25%), IDH2 (25%), NPM1 (25%), IDH1 (13%), JAK2 (13%) and SF3B1 (13%). Conclusion Currently, most of the clinical biomarkers used to predict AML aggressiveness are based on DNA analysis, but the emergence of mutations is not always associated with phenotypic changes. This study shows that the mitochondrial spare reserve capacity of blasts represents a new functional biomarker based on the assessment of the energetic phenotype and could help the clinicians to determine the prognosis of AML. Moreover we have showed that altering pyruvate metabolism highly decrease spare reserve capacity of blasts and then could be evaluated as metabolic strategies to improve the therapeutic response in patients with AML. Disclosures Kluza: Daiichi-Sankyo: Research Funding.

Regulation of Hox target genes by a DNA bound Homothorax/Hox/Extradenticle complex

Development ◽  
1999 ◽  
Vol 126 (22) ◽  
pp. 5137-5148 ◽  
Author(s):  
H.D. Ryoo ◽  
T. Marty ◽  
F. Casares ◽  
M. Affolter ◽  
R.S. Mann
Keyword(s):  
Nuclear Localization ◽  
Target Genes ◽  
Dominant Negative ◽  
Homeodomain Protein ◽  
Hox Proteins ◽  
Trimeric Complex ◽  
Binding Residue ◽  
Dominant Negative Form

To regulate their target genes, the Hox proteins of Drosophila often bind to DNA as heterodimers with the homeodomain protein Extradenticle (EXD). For EXD to bind DNA, it must be in the nucleus, and its nuclear localization requires a third homeodomain protein, Homothorax (HTH). Here we show that a conserved N-terminal domain of HTH directly binds to EXD in vitro, and is sufficient to induce the nuclear localization of EXD in vivo. However, mutating a key DNA binding residue in the HTH homeodomain abolishes many of its in vivo functions. HTH binds to DNA as part of a HTH/Hox/EXD trimeric complex, and we show that this complex is essential for the activation of a natural Hox target enhancer. Using a dominant negative form of HTH we provide evidence that similar complexes are important for several Hox- and exd-mediated functions in vivo. These data suggest that Hox proteins often function as part of a multiprotein complex, composed of HTH, Hox, and EXD proteins, bound to DNA.

Hibernation, temperature and rates of oxidative phosphorylation by heart mitochondria

1960 ◽  
Vol 198 (2) ◽  
pp. 463-466 ◽  
Author(s):  
Frank E. South
Keyword(s):  
Oxygen Consumption ◽  
Oxidative Phosphorylation ◽  
Incubation Temperature ◽  
Regression Line ◽  
Vertical Displacement ◽  
Heart Mitochondria ◽  
Oxidative Enzymes ◽  
Effect Of Temperature ◽  
The Difference

The effect of temperature on rates of oxidative phosphorylation (pyruvate substrate) by heart mitochondria obtained from hibernating hamsters, control hamsters and rats was studied. Apparent energies of activation ( Ea) determined between 5° and 24°C were, respectively, 20.4, 20.8 and 28.3 Kcal. for the rates of oxygen consumption and 20.6, 21.4 and 29.5 Kcal. for the rates of phosphorylation. The difference between the rats and either group of hamsters were significant statistically. The slope of the regression line fitted to the data obtained from hibernating animals did not differ significantly from that of the control hamsters. However, a parallel vertical displacement of the lines indicated a probable increase in these oxidative enzymes upon preparation for, or during, hibernation. No significant alterations in the efficiency of oxidative phosphorylation with variations in the incubation temperature were noted in any of the preparations.

Oxidative phosphorylation in magnesium and potassium deficiency in the rat

1961 ◽  
Vol 201 (6) ◽  
pp. 1120-1122 ◽  
Author(s):  
R. B. Beechey ◽  
N. W. Alcock ◽  
I. MacIntyre
Keyword(s):  
Oxygen Consumption ◽  
Oxidative Phosphorylation ◽  
Normal Control ◽  
Magnesium Deficiency ◽  
Potassium Deficiency ◽  
Satisfactory Explanation ◽  
Methods Of Isolation

Heart sarcosomes were isolated from magnesium-deficient, potassium-deficient, and normal control rats. Two methods of isolation were used. P/O ratios were determined after measuring the oxygen consumption polarometrically in some cases and mano-metrically in others. No matter which method of isolation was used, or which method of determining the oxygen consumption, no difference could be demonstrated between the ratios obtained using sarcosomes isolated from the control rats and those isolated from the magnesium-deficient or the potassium-deficient rats. The results obtained in magnesium deficiency are not in agreement with those reported in 1957 by Vitale, Nakamura, and Hegsted ( J. Biol. Chem. 228: 573, 1957), who found lowered P/O ratios were associated with magnesium deficiency. While no satisfactory explanation can be found for the differences reported, it is suggested that they can only be ascribed to differences in technique.

Oxidative phosphorylation in cardiac infarct. Effect of glucose-KCl-insulin solution

1965 ◽  
Vol 209 (2) ◽  
pp. 371-375 ◽  
Author(s):  
Edmundo Calva ◽  
Adela Mujica ◽  
Abdo Bisteni ◽  
Demetrio Sodi-Pallares
Keyword(s):  
Oxygen Consumption ◽  
Oxidative Phosphorylation ◽  
Respiratory Control ◽  
Low Oxygen ◽  
Normal Limits ◽  
Functional Aspects ◽  
Insulin Solution ◽  
Effect Of Glucose ◽  
Infarcted Tissue ◽  
Electrocardiographic Abnormalities

Myocardial infarction was produced in dogs by ligature of the anterior descending coronary artery. Sarcosomes were isolated from normal and infarcted tissue. Oxygen consumption was followed polarographically and adenosine triphosphate was measured as glucose 6-phosphate. One group of animals received a continuous infusion of glucose for 12 hr; another group received "polarizing solution" (glucose-KCl-insulin). Sarcosomes from the first had a low oxygen consumption, no respiratory control, and no oxidative phosphorylation. In contrast, the administration of glucose-KCl-insulin solution maintained practically within normal limits these functional aspects of the sarcosomes. The reversal of electrocardiographic abnormalities by the administration of the polarizing solution coincided with improvement of such biochemical functions. Anesthesia and surgical handling did not appear to modify the behavior of the sarcosomes.

scholarly journals OXIDATIVE PHOSPHORYLATION IN MITOCHONDRIA FROM LIVERS SHOWING CLOUDY SWELLING

1956 ◽  
Vol 2 (3) ◽  
pp. 293-299 ◽  
Author(s):  
Alberto Fonnesu ◽  
Clara Severi
Keyword(s):  
Oxygen Consumption ◽  
Oxidative Phosphorylation ◽  
Guinea Pigs ◽  
Diphtheria Toxin ◽  
Cellular Change ◽  
Normal Controls

Using succinate and α-ketoglutarate as substrates, oxidative phosphorylation has been measured in mitochondria isolated from livers showing cloudy swelling. This cellular change was obtained by injecting rats with S. typhi murium toxin and guinea pigs with diphtheria toxin. It has been found that phosphorylation associated with the oxidation of either of these substrates was partially inhibited in mitochondria from livers showing cloudy swelling, while the oxygen consumption was unchanged. Thus, the P:O ratios for both succinate and α-ketoglutarate were lower in mitochondria from treated animals than they were in normal mitochondria. Dephosphorylation of ATP was not significantly modified in mitochondria from livers showing cloudy swelling as compared with normal controls. No dephosphorylation of AMP and G-6-P was observed either in normal mitochondria or in mitochondria from treated animals.

Nuclear localization of β-catenin and expression of target genes are associated with increased Wnt secretion in oral dysplasia

Oral Oncology ◽  
2019 ◽  
Vol 94 ◽  
pp. 58-67 ◽  
Author(s):  
Montserrat Reyes ◽  
Daniel Peña-Oyarzun ◽  
Andrea Maturana ◽  
Vicente A. Torres
Keyword(s):  
Nuclear Localization ◽  
Target Genes ◽  
Oral Dysplasia
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