References of "Navet, Rachel"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailAtypical Myopathy In Grazing Horses: A First Exploratory Data Analysis
Votion, Dominique ULg; Linden, Annick ULg; Delguste, Catherine ULg et al

in Veterinary Journal (2009), 180(1),

Detailed reference viewed: 223 (43 ULg)
Full Text
Peer Reviewed
See detailDeficiency or inhibition of oxygen sensor Phd1 induces hypoxia tolerance by reprogramming basal metabolism.
Aragones, Julian; Schneider, Martin; Van Geyte, Katie et al

in Nature Genetics (2008), 40

HIF prolyl hydroxylases (PHD1-3) are oxygen sensors that regulate the stability of the hypoxia-inducible factors (HIFs) in an oxygen-dependent manner. Here, we show that loss of Phd1 lowers oxygen ... [more ▼]

HIF prolyl hydroxylases (PHD1-3) are oxygen sensors that regulate the stability of the hypoxia-inducible factors (HIFs) in an oxygen-dependent manner. Here, we show that loss of Phd1 lowers oxygen consumption in skeletal muscle by reprogramming glucose metabolism from oxidative to more anaerobic ATP production through activation of a Pparalpha pathway. This metabolic adaptation to oxygen conservation impairs oxidative muscle performance in healthy conditions, but it provides acute protection of myofibers against lethal ischemia. Hypoxia tolerance is not due to HIF-dependent angiogenesis, erythropoiesis or vasodilation, but rather to reduced generation of oxidative stress, which allows Phd1-deficient myofibers to preserve mitochondrial respiration. Hypoxia tolerance relies primarily on Hif-2alpha and was not observed in heterozygous Phd2-deficient or homozygous Phd3-deficient mice. Of medical importance, conditional knockdown of Phd1 also rapidly induces hypoxia tolerance. These findings delineate a new role of Phd1 in hypoxia tolerance and offer new treatment perspectives for disorders characterized by oxidative stress. [less ▲]

Detailed reference viewed: 46 (10 ULg)
Full Text
Peer Reviewed
See detailMitoproteome plasticity of rat brown adipocytes in response to cold acclimation
Navet, Rachel ULg; Mathy, Grégory ULg; Douette, Pierre ULg et al

in Journal of Proteome Research (2007), 6(1), 25-33

Cold acclimation induces an adaptative increase in respiration in brown adipose tissue (BAT). A comparative analysis by two-dimensional differential in-gel electrophoresis of mitochondrial protein ... [more ▼]

Cold acclimation induces an adaptative increase in respiration in brown adipose tissue (BAT). A comparative analysis by two-dimensional differential in-gel electrophoresis of mitochondrial protein patterns found in rat control and cold-acclimated BAT was performed. A total of 58 proteins exhibiting significant differences in their abundance was unambiguously identified. Proteins implicated in the major catabolic pathways were up-regulated as were ATP synthase and mitofilin. Moreover, these results support the fact that adipocytes can balance their ATP synthesis and their heat production linked to UCP1-sustained uncoupling. [less ▲]

Detailed reference viewed: 52 (10 ULg)
Full Text
Peer Reviewed
See detailMuscle energetics in exercising horses
Votion, Dominique ULg; Navet, Rachel ULg; Lacombe, A. et al

in Equine & Comparative Exercise Physiology (2007), 4

Detailed reference viewed: 42 (10 ULg)
Full Text
Peer Reviewed
See detailHistory and clinical features of atypical myopathy in horses in Belgium (2000-2005)
Votion, D. M.; Linden, Annick ULg; Saegerman, Claude ULg et al

in Journal of Veterinary Internal Medicine (2007), 21(6, Nov-Dec), 1380-1391

Background: The emergent nature of atypical myopathy or atypical myoglobinuria (AM) necessitates precise description of its clinical and epidemiologic features. Purpose: To define key features of AM to ... [more ▼]

Background: The emergent nature of atypical myopathy or atypical myoglobinuria (AM) necessitates precise description of its clinical and epidemiologic features. Purpose: To define key features of AM to help practitioners recognize the disease and to advise owners to take preventive measures. Animals: Belgian cases of AM confirmed by histology (CC horses; n = 57) from autumn 2000 to spring 2005 were included in the study. Co-grazing horses (Co-G horses; n = 77) that remained free of any abnormal clinical signs constituted a control croup. Methods: History, environmental characteristics, clinical signs, and laboratory results associated with AM were determined by a retrospective case series study. Results: Young horses in poor or normal body condition were found to be at risk for AM. Pastures were characterized by poor natural drainage and vegetation of low nutritional value. Features of AM were seasonal occurrence, apparent link with weather conditions fie, lack of solar radiation with no heavy frost and an excess of precipitation or relative humidity), sudden onset of clinical signs, and rapid death. Evaluation of serum creatine kinase activity indicated severe muscle destruction in CC horses and subclinical disease in a few Co-G horses. Conclusions: The association of AM with specific environmental conditions and individual animals suggests that young horses should not be pastured on bare premises subject to humidity when the weather has been very wet and cold for several days. Management of AM outbreaks should include control of Co-G horses who are apparently healthy. [less ▲]

Detailed reference viewed: 283 (29 ULg)
Full Text
Peer Reviewed
See detailSaccharomyces cerevisiae mitoproteome plasticity in response to recombinant alternative ubiquinol oxidase
Mathy, Grégory ULg; Navet, Rachel ULg; Gerkens, Pascal et al

in Journal of Proteome Research (2006), 5(2), 339-348

The energy-dissipating alternative oxidase (AOX) from Hansenula anomala, was expressed in Saccharomyces cerevisiae. The recombinant AOX was functional. A comparative analysis by two-dimensional ... [more ▼]

The energy-dissipating alternative oxidase (AOX) from Hansenula anomala, was expressed in Saccharomyces cerevisiae. The recombinant AOX was functional. A comparative analysis by two-dimensional differential in-gel electrophoresis (2D-DIGE) of mitochondrial protein patterns found in wild-type and recombinant AOX strains was performed. 60 proteins exhibiting a significant difference in their abundance were identified. Interestingly, proteins implicated in major metabolic pathways such as Krebs cycle and amino acid biosynthesis were up-regulated. Surprisingly, an up-regulation of the respiratory-chain complex III was associated with a down-regulation of the ATP synthase complex. [less ▲]

Detailed reference viewed: 90 (13 ULg)
Full Text
Peer Reviewed
See detailUncoupling protein 1 affects the yeast mitoproteome and oxygen free radical production
Douette, Pierre ULg; Gerkens, Pascal; Navet, Rachel ULg et al

in Free Radical Biology & Medicine (2006), 40(2), 303-315

Uncoupling protein I (UCP1) is a mitochondrial inner membrane protein that dissipates the proton electrochemical gradient built up by the respiratory chain. its activity is stimulated by free fatty acids ... [more ▼]

Uncoupling protein I (UCP1) is a mitochondrial inner membrane protein that dissipates the proton electrochemical gradient built up by the respiratory chain. its activity is stimulated by free fatty acids and inhibited by purine nucleotides. Here we investigated how active and regulated recombinant UCP1 expressed in yeast at similar to 1 and similar to 10 mu g/mg of total mitochondrial proteins induced changes in the mitochondrial proteome and in oxygen free radical production. Using two-dimensional differential in-gel electrophoresis (2D-DIGE), we found that most of the proteins involved in the response to ectopically expressed UCP1 are related to energy metabolism. We also quantified the cellular H2O2 release in the absence or in the presence of UCP1. Our results suggest that UCP1 has a dual influence on free radical generation. On one side, FFA-activated UCP1 was able to decrease the superoxide anion production, demonstrating that a decrease in the generation of reactive oxygen species is an obligatory outcome of UCP1 activity even in a heterologous context. On the other side, an increase in UCP1 content was concomitant with an increase in the basal release of superoxide anion by mitochondria as a side consequence of the overall increase in oxidative metabolism. (c) 2005 Elsevier Inc. All rights reserved. [less ▲]

Detailed reference viewed: 43 (16 ULg)
Full Text
Peer Reviewed
See detailMitochondrial UCPs: New insights into regulation and impact
Sluse, Francis ULg; Jarmuszkiewicz, Wieslawa; Navet, Rachel ULg et al

in Biochimica et Biophysica Acta-Bioenergetics (2006), 1757(5-6, Suppl 1), 101

Uncoupling proteins (UCPs) are mitochondrial inner membrane proteins sustaining an inducible proton conductance. They weaken the proton electrochemical gradient built up by the mitochondrial respiratory ... [more ▼]

Uncoupling proteins (UCPs) are mitochondrial inner membrane proteins sustaining an inducible proton conductance. They weaken the proton electrochemical gradient built up by the mitochondrial respiratory chain. Brown fat UCP1 sustains a free fatty acid (FA)-induced purine nucleotide (PN)-inhibited proton conductance. Inhibition of the proton conductance by PN has been considered as a diagnostic of UCP activity. However, conflicting results have been obtained in isolated mitochondria for UCP homologues (i.e., UCP2, UCP3, plant UCP, and protist UCP) where the FFA-activated proton conductance is poorly sensitive to PN under resting respiration conditions. Our recent work clearly indicates that the membranous coenzyme Q, through its redox state, represents a regulator of the inhibition by PN of FFA-activated UCP1 homologues under phosphorylating respiration conditions. Several physiological roles of UCPs have been suggested, including a control of the cellular energy balance as well as the preventive action against oxidative stress. In this paper, we discuss new information emerging from comparative proteomics about the impact of UCPs on mitochondrial physiology, when recombinant UCP1 is expressed in yeast and when UCP2 is over-expressed in hepatic mitochondria during steatosis [less ▲]

Detailed reference viewed: 70 (13 ULg)
Full Text
Peer Reviewed
See detailSteatosis-induced proteomic changes in liver mitochondria evidenced by two-dimensional differential in-gel electrophoresis
Douette, Pierre ULg; Navet, Rachel ULg; Gerkens, Pascal et al

in Journal of Proteome Research (2005), 4(6), 2024-2031

Steatosis encompasses the accumulation of droplets of fats into hepatocytes. In this work, we performed a comparative analysis of mitochondrial protein patterns found in wild-type and steatosis-affected ... [more ▼]

Steatosis encompasses the accumulation of droplets of fats into hepatocytes. In this work, we performed a comparative analysis of mitochondrial protein patterns found in wild-type and steatosis-affected liver using the novel technique two-dimensional differential in-gel electrophoresis (2D-DIGE). A total of 56 proteins exhibiting significant difference in their abundances were unambiguously identified. Interestingly, major proteins that regulate generation and consumption of the acetyl-CoA pool were dramatically changed during steatosis. Many proteins involved in the response to oxidative stress were also affected. [less ▲]

Detailed reference viewed: 34 (6 ULg)
Full Text
Peer Reviewed
See detailSecondary-structure characterization by far-UV CD of highly purified uncoupling protein 1 expressed in yeast
Douette, Pierre ULg; Navet, Rachel ULg; Bouillenne, Fabrice ULg et al

in Biochemical Journal (2004), 380(Pt 1), 139-145

The rat UCP1 (uncoupling protein 1) is a mitochondrial inner-membrane carrier involved in energy dissipation and heat production. We expressed UCP1 carrying a His(6) epitope at its C-terminus in ... [more ▼]

The rat UCP1 (uncoupling protein 1) is a mitochondrial inner-membrane carrier involved in energy dissipation and heat production. We expressed UCP1 carrying a His(6) epitope at its C-terminus in Saccharomyces cerevisiae mitochondria. The recombinant-tagged UCP1 was purified by immobilized metal-ion affinity chromatography to homogeneity (>95 %). This made it suitable for subsequent biophysical characterization. Fluorescence resonance energy transfer experiments showed that n-dodecyl-beta-D-maltoside-solubilized UCPI-His(6) retained its PN (purine nucleotide)-binding capacity. The far-UV CD spectrum of the functional protein clearly indicated the predominance of a-helices in the UCP1 secondary structure. The UCP1 secondary structure exhibited an alpha-helical degree of approx. 68 %, which is at least 25 % higher than the previously reported estimations based on computational predictions. Moreover, the helical content remained unchanged in free and PN-loaded UCP1. A homology model of the first repeat of UCP1, built on the basis of X-ray-solved close parent, the ADP/ATP carrier, strengthened the CD experimental results. Our experimental and computational results indicate that (i) alpha-helices are the major component of UCP1 secondary structure; (ii) PN-binding mechanism does not involve significant secondary-structure rearrangement; and (iii) UCP1 shares similar secondary-structure characteristics with the ADP/ATP carrier, at least for the first repeat. [less ▲]

Detailed reference viewed: 97 (17 ULg)
Full Text
Peer Reviewed
See detailEffects of COX-2 inhibitors on ROS produced by Chlamydia pneumoniae-primed human promonocytic cells (THP-1)
Mouithys-Mickalad, Ange ULg; Deby, Ginette ULg; Dogné, Jean-Michel ULg et al

in Biochemical and Biophysical Research Communications (2004), 325(4), 1122-1130

Chronic inflammation through foam cells and macrophages is important in atherosclerosis development, and can be considered as therapeutic targets. Cyclooxygenase and NADPH-oxidase were expressed within ... [more ▼]

Chronic inflammation through foam cells and macrophages is important in atherosclerosis development, and can be considered as therapeutic targets. Cyclooxygenase and NADPH-oxidase were expressed within atherosclerotic lesions. Reactive oxygen species produced by NADPH oxidase were found to trigger the cyclooxygenase-2 expression. The effects of preferential COX-2 inhibitors on ROS produced by Chlamydia-primed human monocytes (THP-1 cells) were evaluated by fluorescence, chemiluminescence, oxymetry, and EPR spin trapping. Fluorescence assays showed an increased production of ROS with Chlamydia versus cells primed by 10(-8) M PMA. COX-2 inhibitors inhibited in a dose-dependent manner the luminol-enhanced CL while ibuprofen and diclofenac increased the chemiluminescence response. By EPR spin trapping, COX-2 inhibitors, ibuprofen, and diclofenac, exhibited a dose-dependent inhibiting effect (10 and 100 muM) on the EPR signal appearance. Our cell model combining EPR, chemiluminescence, and oxymetry appeared relevant to study the modulating effects of preferential COX-2 inhibitors on the cell oxidant activity and chronic inflammatory diseases. (C) 2004 Elsevier Inc. All rights reserved. [less ▲]

Detailed reference viewed: 125 (36 ULg)