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Antos-Krzeminska N, Kicinska A, Nowak W, Jarmuszkiewicz W. Acanthamoeba castellanii Uncoupling Protein: A Complete Sequence, Activity, and Role in Response to Oxidative Stress. Int J Mol Sci 2023; 24:12501. [PMID: 37569876 PMCID: PMC10419851 DOI: 10.3390/ijms241512501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 08/01/2023] [Accepted: 08/04/2023] [Indexed: 08/13/2023] Open
Abstract
Uncoupling proteins (UCPs) are mitochondrial inner membrane transporters that mediate free-fatty-acid-induced, purine-nucleotide-inhibited proton leak into the mitochondrial matrix, thereby uncoupling respiratory substrate oxidation from ATP synthesis. The aim of this study was to provide functional evidence that the putative Acucp gene of the free-living protozoan amoeba, A. castellanii, encodes the mitochondrial protein with uncoupling activity characteristic of UCPs and to investigate its role during oxidative stress. We report the sequencing and cloning of a complete Acucp coding sequence, its phylogenetic analysis, and the heterologous expression of AcUCP in the S. cerevisiae strain InvSc1. Measurements of mitochondrial respiratory activity and membrane potential indicate that the heterologous expression of AcUCP causes AcUCP-mediated uncoupling activity. In addition, in a model of oxidative stress with increased reactive oxygen species levels (superoxide dismutase 1 knockout yeasts), AcUCP expression strongly promotes cell survival and growth. The level of superoxide anion radicals is greatly reduced in the ΔSOD1 strain expressing AcUCP. These results suggest that AcUCP targeted to yeast mitochondria causes uncoupling and may act as an antioxidant system. Phylogenetic analysis shows that the A. castellanii UCP diverges very early from other UCPs, but clearly locates within the UCP subfamily rather than among other mitochondrial anion carrier proteins.
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Affiliation(s)
- Nina Antos-Krzeminska
- Department of Bioenergetics, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614 Poznan, Poland; (A.K.); (W.J.)
| | - Anna Kicinska
- Department of Bioenergetics, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614 Poznan, Poland; (A.K.); (W.J.)
| | - Witold Nowak
- Molecular Biology Techniques Laboratory, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614 Poznan, Poland;
| | - Wieslawa Jarmuszkiewicz
- Department of Bioenergetics, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614 Poznan, Poland; (A.K.); (W.J.)
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Schulz R, Schlüter KD. Importance of Mitochondria in Cardiac Pathologies: Focus on Uncoupling Proteins and Monoamine Oxidases. Int J Mol Sci 2023; 24:ijms24076459. [PMID: 37047436 PMCID: PMC10095304 DOI: 10.3390/ijms24076459] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 03/22/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023] Open
Abstract
On the one hand, reactive oxygen species (ROS) are involved in the onset and progression of a wide array of diseases. On the other hand, these are a part of signaling pathways related to cell metabolism, growth and survival. While ROS are produced at various cellular sites, in cardiomyocytes the largest amount of ROS is generated by mitochondria. Apart from the electron transport chain and various other proteins, uncoupling protein (UCP) and monoamine oxidases (MAO) have been proposed to modify mitochondrial ROS formation. Here, we review the recent information on UCP and MAO in cardiac injuries induced by ischemia-reperfusion (I/R) as well as protection from I/R and heart failure secondary to I/R injury or pressure overload. The current data in the literature suggest that I/R will preferentially upregulate UCP2 in cardiac tissue but not UCP3. Studies addressing the consequences of such induction are currently inconclusive because the precise function of UCP2 in cardiac tissue is not well understood, and tissue- and species-specific aspects complicate the situation. In general, UCP2 may reduce oxidative stress by mild uncoupling and both UCP2 and UCP3 affect substrate utilization in cardiac tissue, thereby modifying post-ischemic remodeling. MAOs are important for the physiological regulation of substrate concentrations. Upon increased expression and or activity of MAOs, however, the increased production of ROS and reactive aldehydes contribute to cardiac alterations such as hypertrophy, inflammation, irreversible cardiomyocyte injury, and failure.
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Friesen CR, Wapstra E, Olsson M. Of telomeres and temperature: Measuring thermal effects on telomeres in ectothermic animals. Mol Ecol 2022; 31:6069-6086. [PMID: 34448287 DOI: 10.1111/mec.16154] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 07/20/2021] [Accepted: 08/23/2021] [Indexed: 01/31/2023]
Abstract
Ectotherms are classic models for understanding life-history tradeoffs, including the reproduction-somatic maintenance tradeoffs that may be reflected in telomere length and their dynamics. Importantly, life-history traits of ectotherms are tightly linked to their thermal environment, with diverse or synergistic mechanistic explanations underpinning the variation. Telomere dynamics potentially provide a mechanistic link that can be used to monitor thermal effects on individuals in response to climatic perturbations. Growth rate, age and developmental stage are all affected by temperature, which interacts with telomere dynamics in complex and intriguing ways. The physiological processes underpinning telomere dynamics can be visualized and understood using thermal performance curves (TPCs). TPCs reflect the evolutionary history and the thermal environment during an individual's ontogeny. Telomere maintenance should be enhanced at or near the thermal performance optimum of a species, population and individual. The thermal sensitivity of telomere dynamics should reflect the interacting TPCs of the processes underlying them. The key processes directly underpinning telomere dynamics are mitochondrial function (reactive oxygen production), antioxidant activity, telomerase activity and telomere endcap protein status. We argue that identifying TPCs for these processes will significantly help design robust, repeatable experiments and field studies of telomere dynamics in ectotherms. Conceptually, TPCs are a valuable framework to predict and interpret taxon- and population-specific telomere dynamics across thermal regimes. The literature of thermal effects on telomeres in ectotherms is sparse and mostly limited to vertebrates, but our conclusions and recommendations are relevant across ectothermic animals.
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Affiliation(s)
- Christopher R Friesen
- School of Earth, Atmospheric and Life Sciences, The University of Wollongong, Wollongong, New South Wales, Australia.,School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Erik Wapstra
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Mats Olsson
- School of Earth, Atmospheric and Life Sciences, The University of Wollongong, Wollongong, New South Wales, Australia.,Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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Pietrangelo T, Di Filippo ES, Locatelli M, Piacenza F, Farina M, Pavoni E, Di Donato A, Innosa D, Provinciali M, Fulle S. Extracellular Guanosine 5'-Triphosphate Induces Human Muscle Satellite Cells to Release Exosomes Stuffed With Guanosine. Front Pharmacol 2018; 9:152. [PMID: 29615899 PMCID: PMC5865081 DOI: 10.3389/fphar.2018.00152] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 02/13/2018] [Indexed: 11/13/2022] Open
Abstract
The extracellular guanosine 5'-triphosphate, GTP, has been demonstrated to be an enhancer of myogenic cell differentiation in a murine cell line, not yet in human muscle cells. Our hypothesis was that GTP could influence also human skeletal muscle regeneration, specifically in the first phases. We tested GTP stimulus on human muscle precursor cells established in culture by human satellite cells derived from Vastus Lateralis of three young male. Our data show that extracellular GTP (a) up-regulated miRNA (specifically miR133a and miR133b) and myogenic regulator factor and (b) induces human myogenic precursor cells to release exosomes stuffed with guanosine based molecules (mainly guanosine) in the extracellular milieu. We think that probably these exosomes could be addressed to influence by means of their content (mainly guanosine) in paracrine or autocrine manner the surrounding cells and/or at distance other muscles or tissues.
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Affiliation(s)
- Tiziana Pietrangelo
- Dipartimento Neuroscienze Imaging and Scienze Cliniche, Università degli Studi "G. d'Annunzio" Chieti-Pescara, Chieti, Italy
| | - Ester S Di Filippo
- Dipartimento Neuroscienze Imaging and Scienze Cliniche, Università degli Studi "G. d'Annunzio" Chieti-Pescara, Chieti, Italy
| | - Marcello Locatelli
- Dipartimento di Farmacia, Università degli Studi "G. d'Annunzio" Chieti-Pescara, Chieti, Italy
| | - Francesco Piacenza
- IRCCS-Istituto Nazionale di Riposo e Cura per Anziani, Polo Scientifico e Tecnologico, Centro di Tecnologie Avanzate nell'Invecchiamento, Ancona, Italy
| | - Marco Farina
- Dipartimento di Ingegneria dell'Informazione, Università Politecnica delle Marche, Ancona, Italy
| | - Eleonora Pavoni
- Dipartimento di Ingegneria dell'Informazione, Università Politecnica delle Marche, Ancona, Italy
| | - Andrea Di Donato
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States
| | - Denise Innosa
- Facoltà di Bioscienze e Tecnologie Agro-Alimentari e Ambientali, Università di Teramo, Teramo, Italy
| | - Mauro Provinciali
- IRCCS-Istituto Nazionale di Riposo e Cura per Anziani, Polo Scientifico e Tecnologico, Centro di Tecnologie Avanzate nell'Invecchiamento, Ancona, Italy
| | - Stefania Fulle
- Dipartimento Neuroscienze Imaging and Scienze Cliniche, Università degli Studi "G. d'Annunzio" Chieti-Pescara, Chieti, Italy
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Mészáros B, Herczeg G, Bajer K, Török J, Molnár O. Effects of energy and thermoregulation time on physiological state and sexual signal in a lizard. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 327:570-578. [PMID: 29377549 DOI: 10.1002/jez.2143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 12/26/2017] [Accepted: 01/06/2018] [Indexed: 12/12/2022]
Abstract
Theory of sexual selection states that males often develop showy signals, which reduce their survival but increase their reproductive success. During mate choice, these conspicuous signals can be honest indicators of individual quality conveying information about the signaler's physiological state. Sexually selected signals are influenced by many environmental factors; however, whether signals and physiological state are affected together is rarely studied. The ultraviolet-blue throat color of male Lacerta viridis is an intra- and intersexually selected signal connected to blood parasite infection and influenced by environmental factors. The aim of this study was to experimentally investigate how ecologically relevant environmental factors affect color signal intensity and key physiological traits parallel. During the mating season, we exposed 40 adult male lizards infected with blood parasites to food and basking time treatments in a full factorial design. We measured color, amount of reactive oxygen metabolites (ROMs), hematocrit, immunocompetence, and blood parasite intensity before and after treatments. High basking time resulted in elevated immunocompetence coupled with increased ROMs. The high food treatment increased nuptial color brightness, but also increased ROMs and decreased immunocompetence. In summary, our study provides experimental evidence about environmentally induced parallel changes in an honest sexual signal and several quality-indicator physiological traits. We showed that available energy and time for high metabolism have independent and sometimes opposite effects on individual state.
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Affiliation(s)
- Boglárka Mészáros
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Budapest, Hungary
| | - Gábor Herczeg
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Budapest, Hungary
| | - Katalin Bajer
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Budapest, Hungary.,Laboratório de Biogeografia e Macroecologia, Universidade Federal do Rio Grande do Norte Centro de Biociências, Departamento de Botânica, Ecologia e Zoologia, Campus Universitário, Lagoa Nova, Natal-RN, Brazil
| | - János Török
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Budapest, Hungary
| | - Orsolya Molnár
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Budapest, Hungary.,Laboratório de Biogeografia e Macroecologia, Universidade Federal do Rio Grande do Norte Centro de Biociências, Departamento de Botânica, Ecologia e Zoologia, Campus Universitário, Lagoa Nova, Natal-RN, Brazil
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The conserved regulation of mitochondrial uncoupling proteins: From unicellular eukaryotes to mammals. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1858:21-33. [PMID: 27751905 DOI: 10.1016/j.bbabio.2016.10.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/29/2016] [Accepted: 10/13/2016] [Indexed: 12/19/2022]
Abstract
Uncoupling proteins (UCPs) belong to the mitochondrial anion carrier protein family and mediate regulated proton leak across the inner mitochondrial membrane. Free fatty acids, aldehydes such as hydroxynonenal, and retinoids activate UCPs. However, there are some controversies about the effective action of retinoids and aldehydes alone; thus, only free fatty acids are commonly accepted positive effectors of UCPs. Purine nucleotides such as GTP inhibit UCP-mediated mitochondrial proton leak. In turn, membranous coenzyme Q may play a role as a redox state-dependent metabolic sensor that modulates the complete activation/inhibition of UCPs. Such regulation has been observed for UCPs in microorganisms, plant and animal UCP1 homologues, and UCP1 in mammalian brown adipose tissue. The origin of UCPs is still under debate, but UCP homologues have been identified in all systematic groups of eukaryotes. Despite the differing levels of amino acid/DNA sequence similarities, functional studies in unicellular and multicellular organisms, from amoebae to mammals, suggest that the mechanistic regulation of UCP activity is evolutionarily well conserved. This review focuses on the regulatory feedback loops of UCPs involving free fatty acids, aldehydes, retinoids, purine nucleotides, and coenzyme Q (particularly its reduction level), which may derive from the early stages of evolution as UCP first emerged.
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Rosendale AJ, Lee RE, Costanzo JP. Effect of physiological stress on expression of glucose transporter 2 in liver of the wood frog, Rana sylvatica. ACTA ACUST UNITED AC 2014; 321:566-76. [PMID: 25384572 DOI: 10.1002/jez.1885] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 07/18/2014] [Accepted: 07/28/2014] [Indexed: 11/11/2022]
Abstract
Glucose transporters (GLUTs) have been implicated in the survival of various physiological stresses in mammals; however, little is known about the role of these proteins in stress tolerance in lower vertebrates. The wood frog (Rana sylvatica), which survives multiple winter-related stresses by copiously mobilizing hepatic glycogen stores, is an interesting subject for the study of glucose transport in amphibians. We examined the effects of several physiological stresses on GLUT2 protein and mRNA levels in the liver of R. sylvatica. Using immunoblotting techniques to measure relative GLUT2 abundance, we found that GLUT2 numbers increased in response to organismal freezing, hypoxia exposure, and glucose loading; whereas, experimental dehydration and urea loading did not affect GLUT2 abundance. GLUT2 mRNA levels, assessed using quantitative real-time polymerase chain reaction, changed in accordance with protein abundance for most stresses, indicating that transcriptional regulation of GLUT2 occurs in response to stress. Overall, hepatic GLUT2 seems to be important in stress survival in R. sylvatica and is regulated to meet the physiological need to accumulate glucose.
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Tang X, Xin Y, Wang H, Li W, Zhang Y, Liang S, He J, Wang N, Ma M, Chen Q. Metabolic characteristics and response to high altitude in Phrynocephalus erythrurus (Lacertilia: Agamidae), a lizard dwell at altitudes higher than any other living lizards in the world. PLoS One 2013; 8:e71976. [PMID: 23951275 PMCID: PMC3737200 DOI: 10.1371/journal.pone.0071976] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Accepted: 07/07/2013] [Indexed: 11/18/2022] Open
Abstract
Metabolic response to high altitude remains poorly explored in reptiles. In the present study, the metabolic characteristics of Phrynocephaluserythrurus (Lacertilia: Agamidae), which inhabits high altitudes (4500 m) and Phrynocephalusprzewalskii (Lacertilia: Agamidae), which inhabits low altitudes, were analysed to explore the metabolic regulatory strategies for lizards living at high-altitude environments. The results indicated that the mitochondrial respiratory rates of P. erythrurus were significantly lower than those of P. przewalskii, and that proton leak accounts for 74~79% of state 4 and 7~8% of state3 in P. erythrurus vs. 43~48% of state 4 and 24~26% of state3 in P. przewalskii. Lactate dehydrogenase (LDH) activity in P. erythrurus was lower than in P. przewalskii, indicating that at high altitude the former does not, relatively, have a greater reliance on anaerobic metabolism. A higher activity related to β-hydroxyacyl coenzyme A dehydrogenase (HOAD) and the HOAD/citrate synthase (CS) ratio suggested there was a possible higher utilization of fat in P. erythrurus. The lower expression of PGC-1α and PPAR-γ in P. erythrurus suggested their expression was not influenced by cold and low PO2 at high altitude. These distinct characteristics of P. erythrurus are considered to be necessary strategies in metabolic regulation for living at high altitude and may effectively compensate for the negative influence of cold and low PO2.
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Affiliation(s)
- Xiaolong Tang
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China
| | - Ying Xin
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China
| | - Huihui Wang
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China
| | - Weixin Li
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China
| | - Yang Zhang
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China
| | - Shiwei Liang
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China
| | - Jianzheng He
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China
| | - Ningbo Wang
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China
| | - Ming Ma
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China
| | - Qiang Chen
- Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China
- * E-mail:
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Functional characterization of an uncoupling protein in goldfish white skeletal muscle. J Bioenerg Biomembr 2013; 45:243-51. [DOI: 10.1007/s10863-013-9512-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 04/05/2013] [Indexed: 11/27/2022]
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10
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Yu SJ, Liu HC, Ling-Ling E, Wang DS, Zhu GX. Proliferation and differentiation of osteoblasts from the mandible of osteoporotic rats. Exp Biol Med (Maywood) 2012; 237:395-406. [PMID: 22550338 DOI: 10.1258/ebm.2011.011217] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The objective of this study was to identify the differences between osteoblasts derived from normal adult rat mandibles and osteoporotic adult rats. An osteoporotic animal model was established by performing a bilateral ovariectomy (ovx group). The proliferation and differentiation abilities of osteoblasts were determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-2H-tetrazolium bromide), alkaline phosphatase (ALP) and osteocalcin release (OC) assays. Transmission electron microscopy (TEM) was performed to assess differences in the ultrastructure. Proliferating cell nuclear antigen (PCNA) and uncoupling protein 2 (UCP2) protein concentrations were analyzed by Western blot. In addition, UCP2 protein in osteoblasts was assessed by immunohistochemistry staining. ATP and reactive oxygen species (ROS) concentrations were analyzed separately with ATP and ROS quantification kits. At four and 12 weeks after the operation, osteoblasts of the ovx group showed earlier attachment, fewer dead cells and faster growth compared with cells in the sham group. TEM showed that osteoblasts of the ovx group had fewer folds, lysosomes, peroxisomes and less rough endoplasmic reticulum. The results of the MTT, ALP activity and OC assays were all higher in osteoblasts from the ovx group at four or 12 weeks postsurgery than osteoblasts from the sham group. PCNA protein concentrations in the ovx group increased significantly compared with those of the sham group at four or 12 weeks after the operation, but UCP2 concentrations decreased over the same time period. UCP2 immunohistochemical staining of osteoblasts showed that the protein was concentrated in the cytoplasm and that the osteoblasts from the sham group had higher expression than those from the ovx group. The ATP and ROS concentrations of the ovx groups were significantly higher than the sham groups at four or 12 weeks postsurgery. Therefore, we concluded that there are differences in cell ultrastructure, proliferation, differentiation, ATP and ROS concentrations, and PCNA and UCP2 protein expression levels in osteoblasts from the mandibles of rats of the ovx group compared with those from the sham group.
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Affiliation(s)
- Shu-Juan Yu
- Department of Stomatology, The General Hospital of Jinan Military Region of PLA, Jinan 250031, China
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Seebacher F, Brand MD, Else PL, Guderley H, Hulbert AJ, Moyes CD. Plasticity of oxidative metabolism in variable climates: molecular mechanisms. Physiol Biochem Zool 2010; 83:721-32. [PMID: 20586603 DOI: 10.1086/649964] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Converting food to chemical energy (ATP) that is usable by cells is a principal requirement to sustain life. The rate of ATP production has to be sufficient for housekeeping functions, such as protein synthesis and maintaining membrane potentials, as well as for growth and locomotion. Energy metabolism is temperature sensitive, and animals respond to environmental variability at different temporal levels, from within-individual to evolutionary timescales. Here we review principal molecular mechanisms that underlie control of oxidative ATP production in response to climate variability. Nuclear transcription factors and coactivators control expression of mitochondrial proteins and abundance of mitochondria. Fatty acid and phospholipid concentrations of membranes influence the activity of membrane-bound proteins as well as the passive leak of protons across the mitochondrial membrane. Passive proton leak as well as protein-mediated proton leak across the inner mitochondrial membrane determine the efficacy of ATP production but are also instrumental in endothermic heat production and as a defense against reactive oxygen species. Both transcriptional mechanisms and membrane composition interact with environmental temperature and diet, and this interaction between diet and temperature in determining mitochondrial function links the two major environmental variables that are affected by changing climates. The limits to metabolic plasticity could be set by the production of reactive oxygen species leading to cellular damage, limits to substrate availability in mitochondria, and a disproportionally large increase in proton leak over ATP production.
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Affiliation(s)
- Frank Seebacher
- School of Biological Sciences, University of Sydney, Sydney, New South Wales 2006, Australia.
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Rey B, Roussel D, Romestaing C, Belouze M, Rouanet JL, Desplanches D, Sibille B, Servais S, Duchamp C. Up-regulation of avian uncoupling protein in cold-acclimated and hyperthyroid ducklings prevents reactive oxygen species production by skeletal muscle mitochondria. BMC PHYSIOLOGY 2010; 10:5. [PMID: 20426850 PMCID: PMC2867930 DOI: 10.1186/1472-6793-10-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 04/28/2010] [Indexed: 12/13/2022]
Abstract
Background Although identified in several bird species, the biological role of the avian homolog of mammalian uncoupling proteins (avUCP) remains extensively debated. In the present study, the functional properties of isolated mitochondria were examined in physiological or pharmacological situations that induce large changes in avUCP expression in duckling skeletal muscle. Results The abundance of avUCP mRNA, as detected by RT-PCR in gastrocnemius muscle but not in the liver, was markedly increased by cold acclimation (CA) or pharmacological hyperthyroidism but was down-regulated by hypothyroidism. Activators of UCPs, such as superoxide with low doses of fatty acids, stimulated a GDP-sensitive proton conductance across the inner membrane of muscle mitochondria from CA or hyperthyroid ducklings. The stimulation was much weaker in controls and not observed in hypothyroid ducklings or in any liver mitochondrial preparations. The production of endogenous mitochondrial reactive oxygen species (ROS) was much lower in muscle mitochondria from CA and hyperthyroid ducklings than in the control or hypothyroid groups. The addition of GDP markedly increased the mitochondrial ROS production of CA or hyperthyroid birds up to, or above, the level of control or hypothyroid ducklings. Differences in ROS production among groups could not be attributed to changes in antioxidant enzyme activities (superoxide dismutase or glutathione peroxidase). Conclusion This work provides the first functional in vitro evidence that avian UCP regulates mitochondrial ROS production in situations of enhanced metabolic activity.
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Affiliation(s)
- Benjamin Rey
- Université de Lyon, F-69000, Lyon; Laboratoire de Physiologie Intégrative, Cellulaire et Moléculaire, CNRS - UMR 5123 Université Lyon 1, 43 Bvd 11 Novembre 1918, F-69622 Villeurbanne Cedex, France.
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13
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The Connection Between Oxidative Stress and Estivation in Gastropods and Anurans. AESTIVATION 2010; 49:47-61. [DOI: 10.1007/978-3-642-02421-4_3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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14
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Oxygen recovery up-regulates avian UCP and ANT in newly hatched ducklings. J Comp Physiol B 2009; 180:239-46. [DOI: 10.1007/s00360-009-0409-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 09/06/2009] [Accepted: 09/23/2009] [Indexed: 12/28/2022]
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15
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High anoxia tolerance in the subterranean salamander Proteus anguinus without oxidative stress nor activation of antioxidant defenses during reoxygenation. J Comp Physiol B 2009; 179:543-51. [PMID: 19148651 DOI: 10.1007/s00360-008-0338-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Revised: 12/18/2008] [Accepted: 12/23/2008] [Indexed: 12/12/2022]
Abstract
The present study describes a high anoxia tolerance in an amphibian at high temperature. Indeed, the subterranean salamander Proteus anguinus survived 12 h under anoxia at 12 degrees C. Surprisingly, such experimental conditions did not affect P. anguinus oxidative status while muscles and liver antioxidant enzymes activities decreased under 8 h anoxia and only return to basal level during reoxygenation. To test if such adaptation is common in Urodels, equivalent experimentations have been conducted on another newt: the stream-dwelling Calotriton asper. This latter species exhibited only 1.5 h survival under anoxia in spite of higher antioxidant enzymes activities than P. anguinus. Furthermore, aerobic recovery after 1 h anoxia induced a 30% increase of oxidative damage partly explained by SOD and CAT activities that did not return to control values during reoxygenation, demonstrating a lower capacity to counteract ROS overproduction than P. anguinus. In addition, uncoupling protein (UCP) transcript was for the first time detected, partly sequenced and quantified in amphibian muscles and liver. UCP may be considered as a ROS production attenuator by mediating a discharge of the proton gradient generated by the respiratory chain. The putative role of UCP in post-anoxic oxidative status of both species is discussed.
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