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Sample records for normal mitochondrial function

  1. Mitochondrial histone-like DNA-binding proteins are essential for normal cell growth and mitochondrial function in Crithidia fasciculata

    Czech Academy of Sciences Publication Activity Database

    Avliyakulov, N. K.; Lukeš, Julius; Ray, D. S.

    2004-01-01

    Roč. 3, č. 2 (2004), s. 518-526 ISSN 1535-9778 R&D Projects: GA AV ČR IAA5022302 Institutional research plan: CEZ:AV0Z6022909 Keywords : cell growth * mitochondrial function * Kinetoplastida Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.954, year: 2004

  2. Impaired skeletal muscle mitochondrial function in morbidly obese patients is normalized one year after bariatric surgery.

    Science.gov (United States)

    Vijgen, Guy H E J; Bouvy, Nicole D; Hoeks, Joris; Wijers, Sander; Schrauwen, Patrick; van Marken Lichtenbelt, Wouter D

    2013-01-01

    Obesity and type 2 diabetes are associated with impaired skeletal muscle mitochondrial metabolism. As an intrinsic characteristic of an individual, skeletal muscle mitochondrial dysfunction could be a risk factor for weight gain and obesity-associated co-morbidities, such as type 2 diabetes. On the other hand, impaired skeletal muscle metabolism could be a consequence of obesity. We hypothesize that marked weight loss after bariatric surgery recovers skeletal muscle mitochondrial function. Skeletal muscle mitochondrial function as assessed by high-resolution respirometry was measured in 8 morbidly obese patients (body mass index [BMI], 41.3±4.7 kg/m(2); body fat, 48.3%±5.2%) before and 1 year after bariatric surgery (mean weight loss: 35.0±8.6 kg). The results were compared with a lean (BMI 22.8±1.1 kg/m(2); body fat, 15.6%±4.7%) and obese (BMI 33.5±4.2 kg/m(2); body fat, 34.1%±6.3%) control group. Before surgery, adenosine diphosphate (ADP)-stimulated (state 3) respiration on glutamate/succinate was decreased compared with lean patients (9.5±2.4 versus 15.6±4.4 O2 flux/mtDNA; Psurgery, mitochondrial function was comparable to that of lean controls (after weight loss, 12.3±5.5; lean, 15.6±4.4 O2 flux/mtDNA). In addition, we observed an increased state 3 respiration on a lipid substrate after weight loss (10.0±3.2 versus 14.0±6.6 O2 flux/mtDNA; Pweight loss. Copyright © 2013 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

  3. Patients with type 2 diabetes have normal mitochondrial function in skeletal muscle

    DEFF Research Database (Denmark)

    Boushel, R; Gnaiger, E; Schjerling, P

    2007-01-01

    AIMS/HYPOTHESIS: Insulin resistance and type 2 diabetes are associated with mitochondrial dysfunction. The aim of the present study was to test the hypothesis that oxidative phosphorylation and electron transport capacity are diminished in the skeletal muscle of type 2 diabetic subjects, as a res......AIMS/HYPOTHESIS: Insulin resistance and type 2 diabetes are associated with mitochondrial dysfunction. The aim of the present study was to test the hypothesis that oxidative phosphorylation and electron transport capacity are diminished in the skeletal muscle of type 2 diabetic subjects...

  4. Mitochondrial functionality in female reproduction

    Directory of Open Access Journals (Sweden)

    Łukasz Gąsior

    2017-01-01

    Full Text Available In most animal species female germ cells are the source of mitochondrial genome for the whole body of individuals. As a source of mitochondrial DNA for future generations the mitochondria in the female germ line undergo dynamic quantitative and qualitative changes. In addition to maintaining the intact template of mitochondrial genome from one generation to another, mitochondrial role in oocytes is much more complex and pleiotropic. The quality of mitochondria determines the ability of meiotic divisions, fertilization ability, and activation after fertilization or sustaining development of a new embryo. The presence of normal number of functional mitochondria is also crucial for proper implantation and pregnancy maintaining. This article addresses issues of mitochondrial role and function in mammalian oocyte and presents new approaches in studies of mitochondrial function in female germ cells.

  5. Early Infantile Epileptic Encephalopathy in an STXBP1 Patient with Lactic Acidemia and Normal Mitochondrial Respiratory Chain Function

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    Dong Li

    2016-01-01

    Full Text Available A wide range of clinical findings have been associated with mutations in Syntaxin Binding Protein 1 (STXBP1, including multiple forms of epilepsy, nonsyndromic intellectual disability, and movement disorders. STXBP1 mutations have recently been associated with mitochondrial pathology, although it remains unclear if this phenotype is a part of the core feature for this gene disorder. We report a 7-year-old boy who presented for diagnostic evaluation of intractable epilepsy, episodic ataxia, resting tremor, and speech regression following a period of apparently normal early development. Mild lactic acidemia was detected on one occasion at the time of an intercurrent illness. Due to the concern for mitochondrial disease, ophthalmologic evaluation was performed that revealed bilateral midperiphery pigmentary mottling. Optical coherence tomography (OCT testing demonstrated a bilaterally thickened ganglion cell layer in the perifovea. Skeletal muscle biopsy analysis showed no mitochondrial abnormalities or respiratory chain dysfunction. Exome sequencing identified a de novo c.1651C>T (p.R551C mutation in STXBP1. Although mitochondrial dysfunction has been reported in some individuals, our proband had only mild lactic acidemia and no skeletal muscle tissue evidence of mitochondrial disease pathology. Thus, mitochondrial dysfunction is not an obligate feature of STXBP1 disease.

  6. Increased intrinsic mitochondrial function in humans with mitochondrial haplogroup H

    DEFF Research Database (Denmark)

    Larsen, Steen; Díez-Sánchez, Carmen; Rabøl, Rasmus

    2014-01-01

    and determined their mitochondrial haplogroup, mitochondrial oxidative phosphorylation capacity (OXPHOS), mitochondrial content (citrate synthase (CS)) and VO2max. Intrinsic mitochondrial function is calculated as mitochondrial OXPHOS capacity divided by mitochondrial content (CS). Haplogroup H showed a 30......% higher intrinsic mitochondrial function compared with the other haplo group U. There was no relationship between haplogroups and VO2max. In skeletal muscle from men with mitochondrial haplogroup H, an increased intrinsic mitochondrial function is present....

  7. Imeglimin normalizes glucose tolerance and insulin sensitivity and improves mitochondrial function in liver of a high-fat, high-sucrose diet mice model.

    Science.gov (United States)

    Vial, Guillaume; Chauvin, Marie-Agnès; Bendridi, Nadia; Durand, Annie; Meugnier, Emmanuelle; Madec, Anne-Marie; Bernoud-Hubac, Nathalie; Pais de Barros, Jean-Paul; Fontaine, Éric; Acquaviva, Cécile; Hallakou-Bozec, Sophie; Bolze, Sébastien; Vidal, Hubert; Rieusset, Jennifer

    2015-06-01

    Imeglimin is the first in a new class of oral glucose-lowering agents currently in phase 2b development. Although imeglimin improves insulin sensitivity in humans, the molecular mechanisms are unknown. This study used a model of 16-week high-fat, high-sucrose diet (HFHSD) mice to characterize its antidiabetic effects. Six-week imeglimin treatment significantly decreased glycemia, restored normal glucose tolerance, and improved insulin sensitivity without modifying organs, body weights, and food intake. This was associated with an increase in insulin-stimulated protein kinase B phosphorylation in the liver and muscle. In liver mitochondria, imeglimin redirects substrate flows in favor of complex II, as illustrated by increased respiration with succinate and by the restoration of respiration with glutamate/malate back to control levels. In addition, imeglimin inhibits complex I and restores complex III activities, suggesting an increase in fatty acid oxidation, which is supported by an increase in hepatic 3-hydroxyacetyl-CoA dehydrogenase activity and acylcarnitine profile and the reduction of liver steatosis. Imeglimin also reduces reactive oxygen species production and increases mitochondrial DNA. Finally, imeglimin effects on mitochondrial phospholipid composition could participate in the benefit of imeglimin on mitochondrial function. In conclusion, imeglimin normalizes glucose tolerance and insulin sensitivity by preserving mitochondrial function from oxidative stress and favoring lipid oxidation in liver of HFHSD mice. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  8. CFTR activity and mitochondrial function

    Directory of Open Access Journals (Sweden)

    Angel Gabriel Valdivieso

    2013-01-01

    Full Text Available Cystic Fibrosis (CF is a frequent and lethal autosomal recessive disease, caused by mutations in the gene encoding the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR. Before the discovery of the CFTR gene, several hypotheses attempted to explain the etiology of this disease, including the possible role of a chloride channel, diverse alterations in mitochondrial functions, the overexpression of the lysosomal enzyme α-glucosidase and a deficiency in the cytosolic enzyme glucose 6-phosphate dehydrogenase. Because of the diverse mitochondrial changes found, some authors proposed that the affected gene should codify for a mitochondrial protein. Later, the CFTR cloning and the demonstration of its chloride channel activity turned the mitochondrial, lysosomal and cytosolic hypotheses obsolete. However, in recent years, using new approaches, several investigators reported similar or new alterations of mitochondrial functions in Cystic Fibrosis, thus rediscovering a possible role of mitochondria in this disease. Here, we review these CFTR-driven mitochondrial defects, including differential gene expression, alterations in oxidative phosphorylation, calcium homeostasis, oxidative stress, apoptosis and innate immune response, which might explain some characteristics of the complex CF phenotype and reveals potential new targets for therapy.

  9. High-resolution respirometry of fine-needle muscle biopsies in pre-manifest Huntington's disease expansion mutation carriers shows normal mitochondrial respiratory function.

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    Eva Buck

    Full Text Available Alterations in mitochondrial respiration are an important hallmark of Huntington's disease (HD, one of the most common monogenetic causes of neurodegeneration. The ubiquitous expression of the disease causing mutant huntingtin gene raises the prospect that mitochondrial respiratory deficits can be detected in skeletal muscle. While this tissue is readily accessible in humans, transgenic animal models offer the opportunity to cross-validate findings and allow for comparisons across organs, including the brain. The integrated respiratory chain function of the human vastus lateralis muscle was measured by high-resolution respirometry (HRR in freshly taken fine-needle biopsies from seven pre-manifest HD expansion mutation carriers and nine controls. The respiratory parameters were unaffected. For comparison skeletal muscle isolated from HD knock-in mice (HdhQ111 as well as a broader spectrum of tissues including cortex, liver and heart muscle were examined by HRR. Significant changes of mitochondrial respiration in the HdhQ knock-in mouse model were restricted to the liver and the cortex. Mitochondrial mass as quantified by mitochondrial DNA copy number and citrate synthase activity was stable in murine HD-model tissue compared to control. mRNA levels of key enzymes were determined to characterize mitochondrial metabolic pathways in HdhQ mice. We demonstrated the feasibility to perform high-resolution respirometry measurements from small human HD muscle biopsies. Furthermore, we conclude that alterations in respiratory parameters of pre-manifest human muscle biopsies are rather limited and mirrored by a similar absence of marked alterations in HdhQ skeletal muscle. In contrast, the HdhQ111 murine cortex and liver did show respiratory alterations highlighting the tissue specific nature of mutant huntingtin effects on respiration.

  10. Normal Functioning Family

    Science.gov (United States)

    ... Spread the Word Shop AAP Find a Pediatrician Family Life Medical Home Family Dynamics Adoption & Foster Care ... Español Text Size Email Print Share Normal Functioning Family Page Content Article Body Is there any way ...

  11. Overexpression of mitochondrial sirtuins alters glycolysis and mitochondrial function in HEK293 cells.

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    Michelle Barbi de Moura

    Full Text Available SIRT3, SIRT4, and SIRT5 are mitochondrial deacylases that impact multiple facets of energy metabolism and mitochondrial function. SIRT3 activates several mitochondrial enzymes, SIRT4 represses its targets, and SIRT5 has been shown to both activate and repress mitochondrial enzymes. To gain insight into the relative effects of the mitochondrial sirtuins in governing mitochondrial energy metabolism, SIRT3, SIRT4, and SIRT5 overexpressing HEK293 cells were directly compared. When grown under standard cell culture conditions (25 mM glucose all three sirtuins induced increases in mitochondrial respiration, glycolysis, and glucose oxidation, but with no change in growth rate or in steady-state ATP concentration. Increased proton leak, as evidenced by oxygen consumption in the presence of oligomycin, appeared to explain much of the increase in basal oxygen utilization. Growth in 5 mM glucose normalized the elevations in basal oxygen consumption, proton leak, and glycolysis in all sirtuin over-expressing cells. While the above effects were common to all three mitochondrial sirtuins, some differences between the SIRT3, SIRT4, and SIRT5 expressing cells were noted. Only SIRT3 overexpression affected fatty acid metabolism, and only SIRT4 overexpression altered superoxide levels and mitochondrial membrane potential. We conclude that all three mitochondrial sirtuins can promote increased mitochondrial respiration and cellular metabolism. SIRT3, SIRT4, and SIRT5 appear to respond to excess glucose by inducing a coordinated increase of glycolysis and respiration, with the excess energy dissipated via proton leak.

  12. Peroxynitrite induced mitochondrial biogenesis following MnSOD knockdown in normal rat kidney (NRK cells

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    Akira Marine

    2014-01-01

    Full Text Available Superoxide is widely regarded as the primary reactive oxygen species (ROS which initiates downstream oxidative stress. Increased oxidative stress contributes, in part, to many disease conditions such as cancer, atherosclerosis, ischemia/reperfusion, diabetes, aging, and neurodegeneration. Manganese superoxide dismutase (MnSOD catalyzes the dismutation of superoxide into hydrogen peroxide which can then be further detoxified by other antioxidant enzymes. MnSOD is critical in maintaining the normal function of mitochondria, thus its inactivation is thought to lead to compromised mitochondria. Previously, our laboratory observed increased mitochondrial biogenesis in a novel kidney-specific MnSOD knockout mouse. The current study used transient siRNA mediated MnSOD knockdown of normal rat kidney (NRK cells as the in vitro model, and confirmed functional mitochondrial biogenesis evidenced by increased PGC1α expression, mitochondrial DNA copy numbers and integrity, electron transport chain protein CORE II, mitochondrial mass, oxygen consumption rate, and overall ATP production. Further mechanistic studies using mitoquinone (MitoQ, a mitochondria-targeted antioxidant and L-NAME, a nitric oxide synthase (NOS inhibitor demonstrated that peroxynitrite (at low micromolar levels induced mitochondrial biogenesis. These findings provide the first evidence that low levels of peroxynitrite can initiate a protective signaling cascade involving mitochondrial biogenesis which may help to restore mitochondrial function following transient MnSOD inactivation.

  13. Intramuscular variation in mitochondrial functionality of beef ...

    African Journals Online (AJOL)

    Intramuscular color stability variations in beef semimembranosus have been reported previously. Mitochondria remain biochemically active in postmortem muscle and can influence fresh beef color stability. However, the role of mitochondrial functionality in intramuscular color variations in beef semimembranosus is yet to be ...

  14. Powering Up Mitochondrial Functions to Treat Mitochondrial Disease

    Science.gov (United States)

    2017-10-01

    Philadelphia, PA. “Listen to your heart” *05/2017 Keystone Symposia—Mitochondria, Metabolism and Heart. Santa Fe, NM. “A heart-derived hormone that...ND6P25L combination was associated with impaired mitochondrial complex I activity, altered mitochondrial morphology, increased reactive oxygen species ...oxygen species production, sensitization of the mitochondrial permeability transition pore, increased somatic mtDNA mutation levels, and shortened

  15. Sugarcane genes related to mitochondrial function

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    Fonseca Ghislaine V.

    2001-01-01

    Full Text Available Mitochondria function as metabolic powerhouses by generating energy through oxidative phosphorylation and have become the focus of renewed interest due to progress in understanding the subtleties of their biogenesis and the discovery of the important roles which these organelles play in senescence, cell death and the assembly of iron-sulfur (Fe/S centers. Using proteins from the yeast Saccharomyces cerevisiae, Homo sapiens and Arabidopsis thaliana we searched the sugarcane expressed sequence tag (SUCEST database for the presence of expressed sequence tags (ESTs with similarity to nuclear genes related to mitochondrial functions. Starting with 869 protein sequences, we searched for sugarcane EST counterparts to these proteins using the basic local alignment search tool TBLASTN similarity searching program run against 260,781 sugarcane ESTs contained in 81,223 clusters. We were able to recover 367 clusters likely to represent sugarcane orthologues of the corresponding genes from S. cerevisiae, H. sapiens and A. thaliana with E-value <= 10-10. Gene products belonging to all functional categories related to mitochondrial functions were found and this allowed us to produce an overview of the nuclear genes required for sugarcane mitochondrial biogenesis and function as well as providing a starting point for detailed analysis of sugarcane gene structure and physiology.

  16. Mitochondrial respiratory function induces endogenous hypoxia.

    Science.gov (United States)

    Prior, Sara; Kim, Ara; Yoshihara, Toshitada; Tobita, Seiji; Takeuchi, Toshiyuki; Higuchi, Masahiro

    2014-01-01

    Hypoxia influences many key biological functions. In cancer, it is generally believed that hypoxic condition is generated deep inside the tumor because of the lack of oxygen supply. However, consumption of oxygen by cancer should be one of the key means of regulating oxygen concentration to induce hypoxia but has not been well studied. Here, we provide direct evidence of the mitochondrial role in the induction of intracellular hypoxia. We used Acetylacetonatobis [2-(2'-benzothienyl) pyridinato-kN, kC3'] iridium (III) (BTP), a novel oxygen sensor, to detect intracellular hypoxia in living cells via microscopy. The well-differentiated cancer cell lines, LNCaP and MCF-7, showed intracellular hypoxia without exogenous hypoxia in an open environment. This may be caused by high oxygen consumption, low oxygen diffusion in water, and low oxygen incorporation to the cells. In contrast, the poorly-differentiated cancer cell lines: PC-3 and MDAMB231 exhibited intracellular normoxia by low oxygen consumption. The specific complex I inhibitor, rotenone, and the reduction of mitochondrial DNA (mtDNA) content reduced intracellular hypoxia, indicating that intracellular oxygen concentration is regulated by the consumption of oxygen by mitochondria. HIF-1α was activated in endogenously hypoxic LNCaP and the activation was dependent on mitochondrial respiratory function. Intracellular hypoxic status is regulated by glucose by parabolic dose response. The low concentration of glucose (0.045 mg/ml) induced strongest intracellular hypoxia possibly because of the Crabtree effect. Addition of FCS to the media induced intracellular hypoxia in LNCaP, and this effect was partially mimicked by an androgen analog, R1881, and inhibited by the anti-androgen, flutamide. These results indicate that mitochondrial respiratory function determines intracellular hypoxic status and may regulate oxygen-dependent biological functions.

  17. Mitochondrial respiratory function induces endogenous hypoxia.

    Directory of Open Access Journals (Sweden)

    Sara Prior

    Full Text Available Hypoxia influences many key biological functions. In cancer, it is generally believed that hypoxic condition is generated deep inside the tumor because of the lack of oxygen supply. However, consumption of oxygen by cancer should be one of the key means of regulating oxygen concentration to induce hypoxia but has not been well studied. Here, we provide direct evidence of the mitochondrial role in the induction of intracellular hypoxia. We used Acetylacetonatobis [2-(2'-benzothienyl pyridinato-kN, kC3'] iridium (III (BTP, a novel oxygen sensor, to detect intracellular hypoxia in living cells via microscopy. The well-differentiated cancer cell lines, LNCaP and MCF-7, showed intracellular hypoxia without exogenous hypoxia in an open environment. This may be caused by high oxygen consumption, low oxygen diffusion in water, and low oxygen incorporation to the cells. In contrast, the poorly-differentiated cancer cell lines: PC-3 and MDAMB231 exhibited intracellular normoxia by low oxygen consumption. The specific complex I inhibitor, rotenone, and the reduction of mitochondrial DNA (mtDNA content reduced intracellular hypoxia, indicating that intracellular oxygen concentration is regulated by the consumption of oxygen by mitochondria. HIF-1α was activated in endogenously hypoxic LNCaP and the activation was dependent on mitochondrial respiratory function. Intracellular hypoxic status is regulated by glucose by parabolic dose response. The low concentration of glucose (0.045 mg/ml induced strongest intracellular hypoxia possibly because of the Crabtree effect. Addition of FCS to the media induced intracellular hypoxia in LNCaP, and this effect was partially mimicked by an androgen analog, R1881, and inhibited by the anti-androgen, flutamide. These results indicate that mitochondrial respiratory function determines intracellular hypoxic status and may regulate oxygen-dependent biological functions.

  18. Mitochondrial structure and function are disrupted by standard isolation methods.

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    Martin Picard

    Full Text Available Mitochondria regulate critical components of cellular function via ATP production, reactive oxygen species production, Ca(2+ handling and apoptotic signaling. Two classical methods exist to study mitochondrial function of skeletal muscles: isolated mitochondria and permeabilized myofibers. Whereas mitochondrial isolation removes a portion of the mitochondria from their cellular environment, myofiber permeabilization preserves mitochondrial morphology and functional interactions with other intracellular components. Despite this, isolated mitochondria remain the most commonly used method to infer in vivo mitochondrial function. In this study, we directly compared measures of several key aspects of mitochondrial function in both isolated mitochondria and permeabilized myofibers of rat gastrocnemius muscle. Here we show that mitochondrial isolation i induced fragmented organelle morphology; ii dramatically sensitized the permeability transition pore sensitivity to a Ca(2+ challenge; iii differentially altered mitochondrial respiration depending upon the respiratory conditions; and iv dramatically increased H(2O(2 production. These alterations are qualitatively similar to the changes in mitochondrial structure and function observed in vivo after cellular stress-induced mitochondrial fragmentation, but are generally of much greater magnitude. Furthermore, mitochondrial isolation markedly altered electron transport chain protein stoichiometry. Collectively, our results demonstrate that isolated mitochondria possess functional characteristics that differ fundamentally from those of intact mitochondria in permeabilized myofibers. Our work and that of others underscores the importance of studying mitochondrial function in tissue preparations where mitochondrial structure is preserved and all mitochondria are represented.

  19. Skeletal Muscle Mitochondrial Function in Polycystic Ovarian Syndrome

    DEFF Research Database (Denmark)

    Rabøl, Rasmus; Svendsen, Pernille Maj; Skovbro, Mette

    2011-01-01

    Objective Polycystic ovarian syndrome (PCOS) is associated with skeletal muscle insulin resistance, which has been linked to decreased mitochondrial function. We measured mitochondrial respiration in lean and obese women with and without PCOS using high-resolution respirometry. Methods Hyperinsul...

  20. Mitochondrial oxidative function and type 2 diabetes

    DEFF Research Database (Denmark)

    Rabøl, Rasmus; Boushel, Robert; Dela, Flemming

    2006-01-01

    The cause of insulin resistance and type 2 diabetes is unknown. The major part of insulin-mediated glucose disposal takes place in the skeletal muscle, and increased amounts of intramyocellular lipid has been associated with insulin resistance and linked to decreased activity of mitochondrial...... oxidative phosphorylation. This review will cover the present knowledge and literature on the topics of the activity of oxidative enzymes and the electron transport chain (ETC) in skeletal muscle of patients with type 2 diabetes. Different methods of studying mitochondrial function are described, including...... discussed. Several studies show reduced activity of oxidative enzymes in skeletal muscle of type 2 diabetics. The reductions are independent of muscle fiber type, and are accompanied by visual evidence of damaged mitochondria. In most studies, the reduced oxidative enzyme activity is explained by decreases...

  1. Mitochondrial Functionality and Chemical Compound Action on Sperm Function.

    Science.gov (United States)

    Amaral, S; S Tavares, R; Baptista, M; Sousa, M I; Silva, A; Escada-Rebelo, S; Paiva, C P; Ramalho-Santos, J

    2016-01-01

    During the last decade, several studies have shown that mitochondrial parameters, such as integrity, respiratory activity, membrane potential and ROS production are intimately linked with sperm quality. Given the limitations of conventional semen analyses in terms of predicting male fertility, an increasing number of studies are focusing on the characterization of sperm mitochondria in order to more accurately assess sperm functionality. Moreover, mitochondria from several organs, such as the liver, have been described as a powerful screening tool for drug safety, being an easy in vitro model to assess the toxicity of distinct families of compounds. Given that mitochondrial functionality is intimately related to sperm homeostasis, it has become important to understand how compounds, ranging from dietary supplements, environmental pollutants, dependency-inducing drugs to pharmacological agents (such as erectile dysfunction-targeted drugs and male contraceptives) affect sperm mitochondrial function. In this review, we discuss studies describing the effects of various chemical agents on spermatozoa, with particular emphasis on mitochondrial function. From the extensive literature analyzed, we conclude that in some cases the role of sperm mitochondria as putative predictors of sperm functionality is very obvious, while in others further studies are needed to clarify this issue.

  2. Mitochondrial base excision repair in mouse synaptosomes during normal aging and in a model of Alzheimer's disease

    DEFF Research Database (Denmark)

    Diaz, Ricardo Gredilla; Weissman, Lior; Yang, JL

    2012-01-01

    Brain aging is associated with synaptic decline and synaptic function is highly dependent on mitochondria. Increased levels of oxidative DNA base damage and accumulation of mitochondrial DNA (mtDNA) mutations or deletions lead to mitochondrial dysfunction, playing an important role in the aging...... process and the pathogenesis of several neurodegenerative diseases. Here we have investigated the repair of oxidative base damage, in synaptosomes of mouse brain during normal aging and in an AD model. During normal aging, a reduction in the base excision repair (BER) capacity was observed...... suggest that the age-related reduction in BER capacity in the synaptosomal fraction might contribute to mitochondrial and synaptic dysfunction during aging. The development of AD-like pathology in the 3xTgAD mouse model was, however, not associated with deficiencies of the BER mechanisms...

  3. Nuclear localization of the mitochondrial ncRNAs in normal and cancer cells.

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    Landerer, Eduardo; Villegas, Jaime; Burzio, Veronica A; Oliveira, Luciana; Villota, Claudio; Lopez, Constanza; Restovic, Franko; Martinez, Ronny; Castillo, Octavio; Burzio, Luis O

    2011-08-01

    We have previously shown a differential expression of a family of mitochondrial ncRNAs in normal and cancer cells. Normal proliferating cells and cancer cells express the sense mitochondrial ncRNA (SncmtRNA). In addition, while normal proliferating cells express two antisense mitochondrial ncRNAs (ASncmtRNAs-1 and -2), these transcripts seem to be universally down-regulated in cancer cells. In situ hybridization (ISH) of some normal and cancer tissues reveals nuclear localization of these transcripts suggesting that they are exported from mitochondria. FISH and confocal microscopy, in situ digestion with RNase previous to ISH and electron microscopy ISH was employed to confirm the extra-mitochondrial localization of the SncmtRNA and the ASncmtRNAs in normal proliferating and cancer cells of human and mouse. In normal human kidney and mouse testis the SncmtRNA and the ASncmtRNAs were found outside the organelle and especially localized in the nucleus associated to heterochromatin. In cancer cells, only the SncmtRNA was expressed and was found associated to heterochromatin and nucleoli. The ubiquitous localization of these mitochondrial transcripts in the nucleus suggests that they are new players in the mitochondrial-nuclear communication pathway or retrograde signaling. Down regulation of the ASncmtRNAs seems to be an important step on neoplastic transformation and cancer progression.

  4. Towards a functional definition of the mitochondrial human proteome

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    Mauro Fasano

    2016-03-01

    Full Text Available The mitochondrial human proteome project (mt-HPP was initiated by the Italian HPP group as a part of both the chromosome-centric initiative (C-HPP and the “biology and disease driven” initiative (B/D-HPP. In recent years several reports highlighted how mitochondrial biology and disease are regulated by specific interactions with non-mitochondrial proteins. Thus, it is of great relevance to extend our present view of the mitochondrial proteome not only to those proteins that are encoded by or transported to mitochondria, but also to their interactors that take part in mitochondria functionality. Here, we propose a graphical representation of the functional mitochondrial proteome by retrieving mitochondrial proteins from the NeXtProt database and adding to the network their interactors as annotated in the IntAct database. Notably, the network may represent a reference to map all the proteins that are currently being identified in mitochondrial proteomics studies.

  5. Improvement of mitochondrial function and dynamics by the metabolic enhancer piracetam.

    Science.gov (United States)

    Stockburger, Carola; Kurz, Christopher; Koch, Konrad A; Eckert, Schamim H; Leuner, Kristina; Müller, Walter E

    2013-10-01

    The metabolic enhancer piracetam is used in many countries to treat cognitive impairment in aging, brain injuries, as well as dementia such as AD (Alzheimer's disease). As a specific feature of piracetam, beneficial effects are usually associated with mitochondrial dysfunction. In previous studies we were able to show that piracetam enhanced ATP production, mitochondrial membrane potential as well as neurite outgrowth in cell and animal models for aging and AD. To investigate further the effects of piracetam on mitochondrial function, especially mitochondrial fission and fusion events, we decided to assess mitochondrial morphology. Human neuroblastoma cells were treated with the drug under normal conditions and under conditions imitating aging and the occurrence of ROS (reactive oxygen species) as well as in stably transfected cells with the human wild-type APP (amyloid precursor protein) gene. This AD model is characterized by expressing only 2-fold more human Aβ (amyloid β-peptide) compared with control cells and therefore representing very early stages of AD when Aβ levels gradually increase over decades. Interestingly, these cells exhibit an impaired mitochondrial function and morphology under baseline conditions. Piracetam is able to restore this impairment and shifts mitochondrial morphology back to elongated forms, whereas there is no effect in control cells. After addition of a complex I inhibitor, mitochondrial morphology is distinctly shifted to punctate forms in both cell lines. Under these conditions piracetam is able to ameliorate morphology in cells suffering from the mild Aβ load, as well as mitochondrial dynamics in control cells.

  6. Sulforaphane is anticonvulsant and improves mitochondrial function.

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    Carrasco-Pozo, Catalina; Tan, Kah Ni; Borges, Karin

    2015-12-01

    The nuclear factor erythroid 2-related factor 2 pathway (Nrf2) has been previously identified to protect the brain against various impacts. Here, we investigated the effect of the Nrf2 activator sulforaphane in various seizure models and hippocampal mitochondrial bioenergetics. We found that daily injections of sulforaphane for 5 days elevated the seizure thresholds to 6 Hz stimulation and fluorothyl-, but not pentylenetetrazole-induced tonic seizures and protected mice against pilocarpine-induced status epilepticus (SE). Also, sulforaphane increased the antioxidant defences within hippocampal formations and blood plasma. In addition, sulforaphane treatment reduced the extent of hippocampal lipid peroxidation 24 h post-SE and protected hippocampal mitochondria against SE-induced reduction in state 2 and uncoupler-stimulated state 3 respiration. SE-mediated partial loss of rotenone-sensitive and complex II-driven respiration was reduced, consistent with the enhanced activities of complexes I and II in sulforaphane-treated SE mice. In mitochondria isolated from both no SE and SE mice, sulforaphane increased state 3 respiration and respiration linked to ATP synthesis, which may contribute to its anticonvulsant and antioxidant effects by providing more ATP for cellular vital and protective functions. However, sulforaphane did not prevent SE-induced hippocampal cell death. In conclusion, sulforaphane and/or Nrf2 activation are viable anticonvulsant strategies, which are antioxidant and enhance mitochondrial function, especially the ability to produce ATP. Sulforaphane was anticonvulsant in two acute mouse models of epilepsy and protected mice against pilocarpine-induced status epilepticus (SE). We also found antioxidant effects of sulforaphane in mouse plasma and hippocampal formations, exhibited by increased catalase and superoxide dismutase (SOD) activity, as well as increased abilities of hippocampal mitochondria to produce ATP. These effects likely underlie

  7. Drosophila pink1 is required for mitochondrial function and interacts genetically with parkin.

    Science.gov (United States)

    Clark, Ira E; Dodson, Mark W; Jiang, Changan; Cao, Joseph H; Huh, Jun R; Seol, Jae Hong; Yoo, Soon Ji; Hay, Bruce A; Guo, Ming

    2006-06-29

    Parkinson's disease is the second most common neurodegenerative disorder and is characterized by the degeneration of dopaminergic neurons in the substantia nigra. Mitochondrial dysfunction has been implicated as an important trigger for Parkinson's disease-like pathogenesis because exposure to environmental mitochondrial toxins leads to Parkinson's disease-like pathology. Recently, multiple genes mediating familial forms of Parkinson's disease have been identified, including PTEN-induced kinase 1 (PINK1; PARK6) and parkin (PARK2), which are also associated with sporadic forms of Parkinson's disease. PINK1 encodes a putative serine/threonine kinase with a mitochondrial targeting sequence. So far, no in vivo studies have been reported for pink1 in any model system. Here we show that removal of Drosophila PINK1 homologue (CG4523; hereafter called pink1) function results in male sterility, apoptotic muscle degeneration, defects in mitochondrial morphology and increased sensitivity to multiple stresses including oxidative stress. Pink1 localizes to mitochondria, and mitochondrial cristae are fragmented in pink1 mutants. Expression of human PINK1 in the Drosophila testes restores male fertility and normal mitochondrial morphology in a portion of pink1 mutants, demonstrating functional conservation between human and Drosophila Pink1. Loss of Drosophila parkin shows phenotypes similar to loss of pink1 function. Notably, overexpression of parkin rescues the male sterility and mitochondrial morphology defects of pink1 mutants, whereas double mutants removing both pink1 and parkin function show muscle phenotypes identical to those observed in either mutant alone. These observations suggest that pink1 and parkin function, at least in part, in the same pathway, with pink1 functioning upstream of parkin. The role of the pink1-parkin pathway in regulating mitochondrial function underscores the importance of mitochondrial dysfunction as a central mechanism of Parkinson's disease

  8. New Therapeutics to Modulate Mitochondrial Function in Neurodegenerative Disorders.

    Science.gov (United States)

    Wilkins, Heather M; Morris, Jill K

    2017-01-01

    Mitochondrial function and energy metabolism are impaired in neurodegenerative diseases. There is evidence for these functional declines both within the brain and systemically in Alzheimer's disease, Parkinson's disease, and Amyotrophic Lateral Sclerosis. Due to these observations, therapeutics targeted to alter mitochondrial function and energy pathways are increasingly studied in pre-clinical and clinical settings. The goal of this article was to review therapies with specific implications on mitochondrial energy metabolism published through May 2016 that have been tested for treatment of neurodegenerative diseases. We discuss implications for mitochondrial dysfunction in neurodegenerative diseases and how this drives new therapeutic initiatives. Thus far, treatments have achieved varying degrees of success. Further investigation into the mechanisms driving mitochondrial dysfunction and bioenergetic failure in neurodegenerative diseases is warranted. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  9. 3D IMAGING OF THE MITOCHONDRIAL REDOX STATE OF RAT HEARTS UNDER NORMAL AND FASTING CONDITIONS.

    Science.gov (United States)

    Xu, He N; Zhou, Rong; Moon, Lily; Feng, Min; Li, Lin Z

    2014-03-01

    imaging of the mitochondrial redox state in the heart and provides a useful tool to study heart metabolism and function under normal, dietary-change and pathological conditions at tissue level.

  10. 3D imaging of the mitochondrial redox state of rat hearts under normal and fasting conditions

    Directory of Open Access Journals (Sweden)

    He N. Xu

    2014-03-01

    feasibility of 3D imaging of the mitochondrial redox state in the heart and provides a useful tool to study heart metabolism and function under normal, dietary-change and pathological conditions at tissue level.

  11. Mitochondrial Dynamics: Functional Link with Apoptosis

    Directory of Open Access Journals (Sweden)

    Hidenori Otera

    2012-01-01

    Full Text Available Mitochondria participate in a variety of physiologic processes, such as ATP production, lipid metabolism, iron-sulfur cluster biogenesis, and calcium buffering. The morphology of mitochondria changes dynamically due to their frequent fusion and division in response to cellular conditions, and these dynamics are an important constituent of apoptosis. The discovery of large GTPase family proteins that regulate mitochondrial dynamics, together with novel insights into the role of mitochondrial fusion and fission in apoptosis, has provided important clues to understanding the molecular mechanisms of cellular apoptosis. In this paper, we briefly summarize current knowledge of the role of mitochondrial dynamics in apoptosis and cell pathophysiology in mammalian cells.

  12. Mitochondrial dynamics: functional link with apoptosis.

    Science.gov (United States)

    Otera, Hidenori; Mihara, Katsuyoshi

    2012-01-01

    Mitochondria participate in a variety of physiologic processes, such as ATP production, lipid metabolism, iron-sulfur cluster biogenesis, and calcium buffering. The morphology of mitochondria changes dynamically due to their frequent fusion and division in response to cellular conditions, and these dynamics are an important constituent of apoptosis. The discovery of large GTPase family proteins that regulate mitochondrial dynamics, together with novel insights into the role of mitochondrial fusion and fission in apoptosis, has provided important clues to understanding the molecular mechanisms of cellular apoptosis. In this paper, we briefly summarize current knowledge of the role of mitochondrial dynamics in apoptosis and cell pathophysiology in mammalian cells.

  13. Neurodegenerative and Fatiguing Illnesses, Infections and Mitochondrial Dysfunction: Use of Natural Supplements to Improve Mitochondrial Function

    Directory of Open Access Journals (Sweden)

    Garth L. Nicolson

    2014-01-01

    Full Text Available Background: Many chronic diseases and illnesses are associated with one or more chronic infections, dysfunction of mitochondria and reduced production of ATP. This results in fatigue and other symptoms that occur in most if not all chronic conditions and diseases. Methods: This is a review of the published literature on chronic infections in neurodegenerative diseases and fatiguing illnesses that are also typified by mitochondrial dysfunction. This contribution also reviews the use of natural supplements to enhance mitochondrial function and reduce the effects of chronic infections to improve overall function in various chronic illnesses. Results: Mitochondrial function can be enhanced by the use of various natural supplements, notably Lipid Replacement Therapy (LRT using glyerolphospholipids and other mitochondrial supplements. In various chronic illnesses that are characterized by the presence of chronic infections, such as intracellular bacteria (Mycoplasma, Borrelia, Chlamydia and other infections and viruses, LRT has proven useful in multiple clinical trials. For example, in clinical studies on chronic fatigue syndrome, fibromyalgia syndrome and other chronic fatiguing illnesses where a large majority of patients have chronic infections, LRT significantly reduced fatigue by 35-43% in different clinical trials and increased mitochondrial function. In clinical trials on patients with multiple intracellular bacterial infections and intractable fatigue LRT plus other mitochondrial supplements significantly decreased fatigue and improved mood and cognition. Conclusions: LRT formulations designed to improve mitochondrial function appear to be useful as non-toxic dietary supplements for reducing fatigue and restoring mitochondrial and other cellular membrane functions in patients with chronic illnesses and multiple chronic infections.

  14. Butyrate enhances mitochondrial function during oxidative stress in cell lines from boys with autism.

    Science.gov (United States)

    Rose, Shannon; Bennuri, Sirish C; Davis, Jakeira E; Wynne, Rebecca; Slattery, John C; Tippett, Marie; Delhey, Leanna; Melnyk, Stephan; Kahler, Stephen G; MacFabe, Derrick F; Frye, Richard E

    2018-02-02

    Butyrate (BT) is a ubiquitous short-chain fatty acid (SCFA) principally derived from the enteric microbiome. BT positively modulates mitochondrial function, including enhancing oxidative phosphorylation and beta-oxidation and has been proposed as a neuroprotectant. BT and other SCFAs have also been associated with autism spectrum disorders (ASD), a condition associated with mitochondrial dysfunction. We have developed a lymphoblastoid cell line (LCL) model of ASD, with a subset of LCLs demonstrating mitochondrial dysfunction (AD-A) and another subset of LCLs demonstrating normal mitochondrial function (AD-N). Given the positive modulation of BT on mitochondrial function, we hypothesized that BT would have a preferential positive effect on AD-A LCLs. To this end, we measured mitochondrial function in ASD and age-matched control (CNT) LCLs, all derived from boys, following 24 and 48 h exposure to BT (0, 0.1, 0.5, and 1 mM) both with and without an in vitro increase in reactive oxygen species (ROS). We also examined the expression of key genes involved in cellular and mitochondrial response to stress. In CNT LCLs, respiratory parameters linked to adenosine triphosphate (ATP) production were attenuated by 1 mM BT. In contrast, BT significantly increased respiratory parameters linked to ATP production in AD-A LCLs but not in AD-N LCLs. In the context of ROS exposure, BT increased respiratory parameters linked to ATP production for all groups. BT was found to modulate individual LCL mitochondrial respiration to a common set-point, with this set-point slightly higher for the AD-A LCLs as compared to the other groups. The highest concentration of BT (1 mM) increased the expression of genes involved in mitochondrial fission (PINK1, DRP1, FIS1) and physiological stress (UCP2, mTOR, HIF1α, PGC1α) as well as genes thought to be linked to cognition and behavior (CREB1, CamKinase II). These data show that the enteric microbiome-derived SCFA BT modulates mitochondrial

  15. Mitochondrial Dynamics: Functional Link with Apoptosis

    OpenAIRE

    Hidenori Otera; Katsuyoshi Mihara

    2012-01-01

    Mitochondria participate in a variety of physiologic processes, such as ATP production, lipid metabolism, iron-sulfur cluster biogenesis, and calcium buffering. The morphology of mitochondria changes dynamically due to their frequent fusion and division in response to cellular conditions, and these dynamics are an important constituent of apoptosis. The discovery of large GTPase family proteins that regulate mitochondrial dynamics, together with novel insights into the role of mitochondrial f...

  16. Protein Carbonylation and Adipocyte Mitochondrial Function*

    Science.gov (United States)

    Curtis, Jessica M.; Hahn, Wendy S.; Stone, Matthew D.; Inda, Jacob J.; Droullard, David J.; Kuzmicic, Jovan P.; Donoghue, Margaret A.; Long, Eric K.; Armien, Anibal G.; Lavandero, Sergio; Arriaga, Edgar; Griffin, Timothy J.; Bernlohr, David A.

    2012-01-01

    Carbonylation is the covalent, non-reversible modification of the side chains of cysteine, histidine, and lysine residues by lipid peroxidation end products such as 4-hydroxy- and 4-oxononenal. In adipose tissue the effects of such modifications are associated with increased oxidative stress and metabolic dysregulation centered on mitochondrial energy metabolism. To address the role of protein carbonylation in the pathogenesis of mitochondrial dysfunction, quantitative proteomics was employed to identify specific targets of carbonylation in GSTA4-silenced or overexpressing 3T3-L1 adipocytes. GSTA4-silenced adipocytes displayed elevated carbonylation of several key mitochondrial proteins including the phosphate carrier protein, NADH dehydrogenase 1α subcomplexes 2 and 3, translocase of inner mitochondrial membrane 50, and valyl-tRNA synthetase. Elevated protein carbonylation is accompanied by diminished complex I activity, impaired respiration, increased superoxide production, and a reduction in membrane potential without changes in mitochondrial number, area, or density. Silencing of the phosphate carrier or NADH dehydrogenase 1α subcomplexes 2 or 3 in 3T3-L1 cells results in decreased basal and maximal respiration. These results suggest that protein carbonylation plays a major instigating role in cytokine-dependent mitochondrial dysfunction and may be linked to the development of insulin resistance in the adipocyte. PMID:22822087

  17. Protein carbonylation and adipocyte mitochondrial function.

    Science.gov (United States)

    Curtis, Jessica M; Hahn, Wendy S; Stone, Matthew D; Inda, Jacob J; Droullard, David J; Kuzmicic, Jovan P; Donoghue, Margaret A; Long, Eric K; Armien, Anibal G; Lavandero, Sergio; Arriaga, Edgar; Griffin, Timothy J; Bernlohr, David A

    2012-09-21

    Carbonylation is the covalent, non-reversible modification of the side chains of cysteine, histidine, and lysine residues by lipid peroxidation end products such as 4-hydroxy- and 4-oxononenal. In adipose tissue the effects of such modifications are associated with increased oxidative stress and metabolic dysregulation centered on mitochondrial energy metabolism. To address the role of protein carbonylation in the pathogenesis of mitochondrial dysfunction, quantitative proteomics was employed to identify specific targets of carbonylation in GSTA4-silenced or overexpressing 3T3-L1 adipocytes. GSTA4-silenced adipocytes displayed elevated carbonylation of several key mitochondrial proteins including the phosphate carrier protein, NADH dehydrogenase 1α subcomplexes 2 and 3, translocase of inner mitochondrial membrane 50, and valyl-tRNA synthetase. Elevated protein carbonylation is accompanied by diminished complex I activity, impaired respiration, increased superoxide production, and a reduction in membrane potential without changes in mitochondrial number, area, or density. Silencing of the phosphate carrier or NADH dehydrogenase 1α subcomplexes 2 or 3 in 3T3-L1 cells results in decreased basal and maximal respiration. These results suggest that protein carbonylation plays a major instigating role in cytokine-dependent mitochondrial dysfunction and may be linked to the development of insulin resistance in the adipocyte.

  18. The mitochondrial function of the cerebral vasculature in insulin-resistant Zucker obese rats.

    Science.gov (United States)

    Merdzo, Ivan; Rutkai, Ibolya; Tokes, Tunde; Sure, Venkata N L R; Katakam, Prasad V G; Busija, David W

    2016-04-01

    Little is known about mitochondrial functioning in the cerebral vasculature during insulin resistance (IR). We examined mitochondrial respiration in isolated cerebral arteries of male Zucker obese (ZO) rats and phenotypically normal Zucker lean (ZL) rats using the Seahorse XFe24 analyzer. We investigated mitochondrial morphology in cerebral blood vessels as well as mitochondrial and nonmitochondrial protein expression levels in cerebral arteries and microvessels. We also measured reactive oxygen species (ROS) levels in cerebral microvessels. Under basal conditions, the mitochondrial respiration components (nonmitochondrial respiration, basal respiration, ATP production, proton leak, and spare respiratory capacity) showed similar levels among the ZL and ZO groups with the exception of maximal respiration, which was higher in the ZO group. We examined the role of nitric oxide by measuring mitochondrial respiration following inhibition of nitric oxide synthase with N(ω)-nitro-l-arginine methyl ester (l-NAME) and mitochondrial activation after administration of diazoxide (DZ). Both ZL and ZO groups showed similar responses to these stimuli with minor variations.l-NAME significantly increased the proton leak, and DZ decreased nonmitochondrial respiration in the ZL group. Other components were not affected. Mitochondrial morphology and distribution within vascular smooth muscle and endothelium as well as mitochondrial protein levels were similar in the arteries and microvessels of both groups. Endothelial nitric oxide synthase (eNOS) and ROS levels were increased in cerebral microvessels of the ZO. Our study suggests that mitochondrial function is not significantly altered in the cerebral vasculature of young ZO rats, but increased ROS production might be due to increased eNOS in the cerebral microcirculation during IR. Copyright © 2016 the American Physiological Society.

  19. Expression of a family of noncoding mitochondrial RNAs distinguishes normal from cancer cells.

    Science.gov (United States)

    Burzio, Verónica A; Villota, Claudio; Villegas, Jaime; Landerer, Eduardo; Boccardo, Enrique; Villa, Luisa L; Martínez, Ronny; Lopez, Constanza; Gaete, Fancy; Toro, Viviana; Rodriguez, Ximena; Burzio, Luis O

    2009-06-09

    We reported the presence in human cells of a noncoding mitochondrial RNA that contains an inverted repeat (IR) of 815 nucleotides (nt) covalently linked to the 5' end of the mitochondrial 16S RNA (16S mtrRNA). The transcript contains a stem-loop structure and is expressed in human proliferating cells but not in resting cells. Here, we demonstrate that, in addition to this transcript, normal human proliferating cells in culture express 2 antisense mitochondrial transcripts. These transcripts also contain stem-loop structures but strikingly they are down-regulated in tumor cell lines and tumor cells present in 17 different tumor types. The differential expression of these transcripts distinguishes normal from tumor cells and might contribute a unique vision on cancer biology and diagnostics.

  20. Defect in mitochondrial functions in damaged human mitral valve

    OpenAIRE

    Shinde, Santosh; Kumar, Pawan; Mishra, Kaushala; Patil, Neela

    2006-01-01

    Mitochondrial diseases are a heterogeneous group of disorders in which a primary mitochondrial dysfunction is proven by morphological, biochemical, and genetic examinations. The mitral valve has important function in the regulation of blood flow from one chamber to another. Often, the mitral valve becomes abnormal with age, in Rheumatic fever or it is abnormal from birth (Congenital) or it can be destroyed by infection i.e. bacterial endocarditis and needs replacement. Myocardial function dep...

  1. A role of taurine in mitochondrial function

    DEFF Research Database (Denmark)

    Hansen, Svend Høime; Andersen, Mogens Larsen; Cornett, Claus

    2010-01-01

    and its pKa value is determined to 9.0 (25 degrees C) and 8.6 (37 degrees C), respectively. Localisation of such a low-molecular buffer in the mitochondrial matrix, transforms the matrix into a biochemical reaction chamber for the important matrix-localised enzyme systems. Three acyl-CoA dehydrogenase......The mitochondrial pH gradient across the inner-membrane is stabilised by buffering of the matrix. A low-molecular mass buffer compound has to be localised in the matrix to maintain its alkaline pH value. Taurine is found ubiquitously in animal cells with concentrations in the millimolar range...... enzymes, which are pivotal for beta-oxidation of fatty acids, are demonstrated to have optimal activity in a taurine buffer. By application of the model presented, taurine depletion caused by hyperglycemia could provide a link between mitochondrial dysfunction and diabetes....

  2. Desmin Cytoskeleton Linked to Muscle Mitochondrial Distribution and Respiratory Function

    Science.gov (United States)

    Milner, Derek J.; Mavroidis, Manolis; Weisleder, Noah; Capetanaki, Yassemi

    2000-01-01

    Ultrastructural studies have previously suggested potential association of intermediate filaments (IFs) with mitochondria. Thus, we have investigated mitochondrial distribution and function in muscle lacking the IF protein desmin. Immunostaining of skeletal muscle tissue sections, as well as histochemical staining for the mitochondrial marker enzymes cytochrome C oxidase and succinate dehydrogenase, demonstrate abnormal accumulation of subsarcolemmal clumps of mitochondria in predominantly slow twitch skeletal muscle of desmin-null mice. Ultrastructural observation of desmin-null cardiac muscle demonstrates in addition to clumping, extensive mitochondrial proliferation in a significant fraction of the myocytes, particularly after work overload. These alterations are frequently associated with swelling and degeneration of the mitochondrial matrix. Mitochondrial abnormalities can be detected very early, before other structural defects become obvious. To investigate related changes in mitochondrial function, we have analyzed ADP-stimulated respiration of isolated muscle mitochondria, and ADP-stimulated mitochondrial respiration in situ using saponin skinned muscle fibers. The in vitro maximal rates of respiration in isolated cardiac mitochondria from desmin-null and wild-type mice were similar. However, mitochondrial respiration in situ is significantly altered in desmin-null muscle. Both the maximal rate of ADP-stimulated oxygen consumption and the dissociation constant (K m) for ADP are significantly reduced in desmin-null cardiac and soleus muscle compared with controls. Respiratory parameters for desmin-null fast twitch gastrocnemius muscle were unaffected. Additionally, respiratory measurements in the presence of creatine indicate that coupling of creatine kinase and the adenine translocator is lost in desmin-null soleus muscle. This coupling is unaffected in cardiac muscle from desmin-null animals. All of these studies indicate that desmin IFs play a significant

  3. Mitochondrial structure, function and dynamics are temporally controlled by c-Myc.

    Directory of Open Access Journals (Sweden)

    J Anthony Graves

    Full Text Available Although the c-Myc (Myc oncoprotein controls mitochondrial biogenesis and multiple enzymes involved in oxidative phosphorylation (OXPHOS, the coordination of these events and the mechanistic underpinnings of their regulation remain largely unexplored. We show here that re-expression of Myc in myc-/- fibroblasts is accompanied by a gradual accumulation of mitochondrial biomass and by increases in membrane polarization and mitochondrial fusion. A correction of OXPHOS deficiency is also seen, although structural abnormalities in electron transport chain complexes (ETC are not entirely normalized. Conversely, the down-regulation of Myc leads to a gradual decrease in mitochondrial mass and a more rapid loss of fusion and membrane potential. Increases in the levels of proteins specifically involved in mitochondrial fission and fusion support the idea that Myc affects mitochondrial mass by influencing both of these processes, albeit favoring the latter. The ETC defects that persist following Myc restoration may represent metabolic adaptations, as mitochondrial function is re-directed away from producing ATP to providing a source of metabolic precursors demanded by the transformed cell.

  4. Flow cytometric probing of mitochondrial function in equine peripheral blood mononuclear cells

    Directory of Open Access Journals (Sweden)

    Coignoul Freddy

    2007-09-01

    Full Text Available Abstract Background The morphopathological picture of a subset of equine myopathies is compatible with a primary mitochondrial disease, but functional confirmation in vivo is still pending. The cationic dye JC-1 exhibits potential-dependent accumulation in mitochondria that is detectable by a fluorescence shift from green to orange. As a consequence, mitochondrial membrane potential can be optically measured by the orange/green fluorescence intensity ratio. A flow cytometric standardized analytic procedure of the mitochondrial function of equine peripheral blood mononuclear cells is proposed along with a critical appraisal of the crucial questions of technical aspects, reproducibility, effect of time elapsed between blood sampling and laboratory processing and reference values. Results The JC-1-associated fluorescence orange and green values and their ratio were proved to be stable over time, independent of age and sex and hypersensitive to intoxication with a mitochondrial potential dissipator. Unless time elapsed between blood sampling and laboratory processing does not exceed 5 hours, the values retrieved remain stable. Reference values for clinically normal horses are given. Conclusion Whenever a quantitative measurement of mitochondrial function in a horse is desired, blood samples should be taken in sodium citrate tubes and kept at room temperature for a maximum of 5 hours before the laboratory procedure detailed here is started. The hope is that this new test may help in confirming, studying and preventing equine myopathies that are currently imputed to mitochondrial dysfunction.

  5. Control of mitochondrial function and cell growth by the atypical cadherin Fat1.

    Science.gov (United States)

    Cao, Longyue L; Riascos-Bernal, Dario F; Chinnasamy, Prameladevi; Dunaway, Charlene M; Hou, Rong; Pujato, Mario A; O'Rourke, Brian P; Miskolci, Veronika; Guo, Liang; Hodgson, Louis; Fiser, Andras; Sibinga, Nicholas E S

    2016-11-24

    Mitochondrial products such as ATP, reactive oxygen species, and aspartate are key regulators of cellular metabolism and growth. Abnormal mitochondrial function compromises integrated growth-related processes such as development and tissue repair, as well as homeostatic mechanisms that counteract ageing and neurodegeneration, cardiovascular disease, and cancer. Physiologic mechanisms that control mitochondrial activity in such settings remain incompletely understood. Here we show that the atypical Fat1 cadherin acts as a molecular 'brake' on mitochondrial respiration that regulates vascular smooth muscle cell (SMC) proliferation after arterial injury. Fragments of Fat1 accumulate in SMC mitochondria, and the Fat1 intracellular domain interacts with multiple mitochondrial proteins, including critical factors associated with the inner mitochondrial membrane. SMCs lacking Fat1 (Fat1 KO ) grow faster, consume more oxygen for ATP production, and contain more aspartate. Notably, expression in Fat1 KO cells of a modified Fat1 intracellular domain that localizes exclusively to mitochondria largely normalizes oxygen consumption, and the growth advantage of these cells can be suppressed by inhibition of mitochondrial respiration, which suggest that a Fat1-mediated growth control mechanism is intrinsic to mitochondria. Consistent with this idea, Fat1 species associate with multiple respiratory complexes, and Fat1 deletion both increases the activity of complexes I and II and promotes the formation of complex-I-containing supercomplexes. In vivo, Fat1 is expressed in injured human and mouse arteries, and inactivation of SMC Fat1 in mice potentiates the response to vascular damage, with markedly increased medial hyperplasia and neointimal growth, and evidence of higher SMC mitochondrial respiration. These studies suggest that Fat1 controls mitochondrial activity to restrain cell growth during the reparative, proliferative state induced by vascular injury. Given recent reports

  6. Inhibition of Mitochondrial Function in Astrocytes: Implications for Neuroprotection

    Science.gov (United States)

    Voloboueva, Ludmila A.; Suh, Sang Won; Swanson, Raymond A.; Giffard, Rona G.

    2011-01-01

    Much evidence suggests that astrocytes protect neurons against ischemic injury. Although astrocytes are more resistant to some insults than neurons, few studies offer insight into the real time changes of astrocytic protective functions with stress. Mitochondria are one of the primary targets of ischemic injury in astrocytes. We investigated the time course of changes in astrocytic ATP levels, plasma membrane potential, and glutamate uptake, a key protective function, induced by mitochondrial inhibition. Our results show that significant functional change precedes reduction in astrocytic viability with mitochondrial inhibition. Using the mitochondrial inhibitor fluorocitrate (FC, 0.25 mM) that is preferentially taken by astrocytes we found that inhibition of astrocyte mitochondria increased vulnerability of co-cultured neurons to glutamate toxicity. In our studies the rates of FC-induced astrocytic mitochondrial depolarization were accelerated in mixed astrocyte/neuron cultures. We hypothesized that the more rapid mitochondrial depolarization was promoted by an additional energetic demand imposed be the co-cultured neurons. To test this hypothesis we exposed pure astrocytic cultures to 0.01 –1 mM aspartate as a metabolic load. Aspartate application accelerated the rates of FC-induced mitochondrial depolarization, and, at 1 mM, induced astrocytic death, suggesting that strong energetic demands during ischemia can compromise astrocytic function and viability. PMID:17488276

  7. Cisplatin Induces a Mitochondrial-ROS Response That Contributes to Cytotoxicity Depending on Mitochondrial Redox Status and Bioenergetic Functions

    Science.gov (United States)

    Marullo, Rossella; Werner, Erica; Degtyareva, Natalya; Moore, Bryn; Altavilla, Giuseppe; Ramalingam, Suresh S.; Doetsch, Paul W.

    2013-01-01

    Cisplatin is one of the most effective and widely used anticancer agents for the treatment of several types of tumors. The cytotoxic effect of cisplatin is thought to be mediated primarily by the generation of nuclear DNA adducts, which, if not repaired, cause cell death as a consequence of DNA replication and transcription blockage. However, the ability of cisplatin to induce nuclear DNA (nDNA) damage per se is not sufficient to explain its high degree of effectiveness nor the toxic effects exerted on normal, post-mitotic tissues. Oxidative damage has been observed in vivo following exposure to cisplatin in several tissues, suggesting a role for oxidative stress in the pathogenesis of cisplatin-induced dose-limiting toxicities. However, the mechanism of cisplatin-induced generation of ROS and their contribution to cisplatin cytotoxicity in normal and cancer cells is still poorly understood. By employing a panel of normal and cancer cell lines and the budding yeast Saccharomyces cerevisiae as model system, we show that exposure to cisplatin induces a mitochondrial-dependent ROS response that significantly enhances the cytotoxic effect caused by nDNA damage. ROS generation is independent of the amount of cisplatin-induced nDNA damage and occurs in mitochondria as a consequence of protein synthesis impairment. The contribution of cisplatin-induced mitochondrial dysfunction in determining its cytotoxic effect varies among cells and depends on mitochondrial redox status, mitochondrial DNA integrity and bioenergetic function. Thus, by manipulating these cellular parameters, we were able to enhance cisplatin cytotoxicity in cancer cells. This study provides a new mechanistic insight into cisplatin-induced cell killing and may lead to the design of novel therapeutic strategies to improve anticancer drug efficacy. PMID:24260552

  8. Rosiglitazone Improves Stallion Sperm Motility, ATP Content, and Mitochondrial Function.

    Science.gov (United States)

    Swegen, Aleona; Lambourne, Sarah Renay; Aitken, R John; Gibb, Zamira

    2016-11-01

    Media used for equine sperm storage often contain relatively high concentrations of glucose, even though stallion spermatozoa preferentially utilize oxidative phosphorylation (OXPHOS) over glycolysis to generate ATP and support motility. Rosiglitazone is an antidiabetic compound that enhances metabolic flexibility and glucose utilization in various cell types, but its effects on sperm metabolism are unknown. This study investigated the effects of rosiglitazone on stallion sperm function in vitro, along with the possible role of AMP-activated protein kinase (AMPK) in mediating these effects. Spermatozoa were incubated with or without rosiglitazone, GW9662 (an antagonist of peroxisome proliferator-activating receptor-gamma), and compound C (CC; an AMPK inhibitor). Sperm motility, viability, reactive oxygen species production, mitochondrial membrane potential (mMP), ATP content, and glucose uptake capacity were measured. Samples incubated with rosiglitazone displayed significantly higher motility, percentage of cells with normal mMP, ATP content, and glucose uptake capacity, while sperm viability was unaffected. The percentage of spermatozoa positive for mitochondrial ROS was also significantly lower in rosiglitazone-treated samples. AMPK localized to the sperm midpiece, and its phosphorylation, was increased in rosiglitazone-treated spermatozoa. CC decreased sperm AMPK phosphorylation and reduced sperm motility, and successfully inhibited the effects of rosiglitazone. Inclusion of rosiglitazone in a room temperature sperm storage medium maintained sperm motility above 60% for 6 days, attaining significantly higher motility than sperm stored in control media. The ability of rosiglitazone to substantially alleviate the time-dependent deterioration of stallion spermatozoa by diverting metabolism away from OXPHOS and toward glycolysis has novel implications for the long-term, functional preservation of these cells. © 2016 by the Society for the Study of Reproduction

  9. Cellular Allometry of Mitochondrial Functionality Establishes the Optimal Cell Size.

    Science.gov (United States)

    Miettinen, Teemu P; Björklund, Mikael

    2016-11-07

    Eukaryotic cells attempt to maintain an optimal size, resulting in size homeostasis. While cellular content scales isometrically with cell size, allometric laws indicate that metabolism per mass unit should decline with increasing size. Here we use elutriation and single-cell flow cytometry to analyze mitochondrial scaling with cell size. While mitochondrial content increases linearly, mitochondrial membrane potential and oxidative phosphorylation are highest at intermediate cell sizes. Thus, mitochondrial content and functional scaling are uncoupled. The nonlinearity of mitochondrial functionality is cell size, not cell cycle, dependent, and it results in an optimal cell size whereby cellular fitness and proliferative capacity are maximized. While optimal cell size is controlled by growth factor signaling, its establishment and maintenance requires mitochondrial dynamics, which can be controlled by the mevalonate pathway. Thus, optimization of cellular fitness and functionality through mitochondria can explain the requirement for size control, as well as provide means for its maintenance. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  10. DPP4-inhibitor improves neuronal insulin receptor function, brain mitochondrial function and cognitive function in rats with insulin resistance induced by high-fat diet consumption.

    Science.gov (United States)

    Pipatpiboon, Noppamas; Pintana, Hiranya; Pratchayasakul, Wasana; Chattipakorn, Nipon; Chattipakorn, Siriporn C

    2013-03-01

    High-fat diet (HFD) consumption has been demonstrated to cause peripheral and neuronal insulin resistance, and brain mitochondrial dysfunction in rats. Although the dipeptidyl peptidase-4 inhibitor, vildagliptin, is known to improve peripheral insulin sensitivity, its effects on neuronal insulin resistance and brain mitochondrial dysfunction caused by a HFD are unknown. We tested the hypothesis that vildagliptin prevents neuronal insulin resistance, brain mitochondrial dysfunction, learning and memory deficit caused by HFD. Male rats were divided into two groups to receive either a HFD or normal diet (ND) for 12 weeks, after which rats in each group were fed with either vildagliptin (3 mg/kg/day) or vehicle for 21 days. The cognitive function was tested by the Morris Water Maze prior to brain removal for studying neuronal insulin receptor (IR) and brain mitochondrial function. In HFD rats, neuronal insulin resistance and brain mitochondrial dysfunction were demonstrated, with impaired learning and memory. Vildagliptin prevented neuronal insulin resistance by restoring insulin-induced long-term depression and neuronal IR phosphorylation, IRS-1 phosphorylation and Akt/PKB-ser phosphorylation. It also improved brain mitochondrial dysfunction and cognitive function. Vildagliptin effectively restored neuronal IR function, increased glucagon-like-peptide 1 levels and prevented brain mitochondrial dysfunction, thus attenuating the impaired cognitive function caused by HFD. © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

  11. Dissecting the role of the mitochondrial chaperone mortalin in Parkinson's disease: functional impact of disease-related variants on mitochondrial homeostasis

    Science.gov (United States)

    Burbulla, Lena F.; Schelling, Carina; Kato, Hiroki; Rapaport, Doron; Woitalla, Dirk; Schiesling, Carola; Schulte, Claudia; Sharma, Manu; Illig, Thomas; Bauer, Peter; Jung, Stephan; Nordheim, Alfred; Schöls, Ludger; Riess, Olaf; Krüger, Rejko

    2010-01-01

    The mitochondrial chaperone mortalin has been linked to neurodegeneration in Parkinson's disease (PD) based on reduced protein levels in affected brain regions of PD patients and its interaction with the PD-associated protein DJ-1. Recently, two amino acid exchanges in the ATPase domain (R126W) and the substrate-binding domain (P509S) of mortalin were identified in Spanish PD patients. Here, we identified a separate and novel variant (A476T) in the substrate-binding domain of mortalin in German PD patients. To define a potential role as a susceptibility factor in PD, we characterized the functions of all three variants in different cellular models. In vitro import assays revealed normal targeting of all mortalin variants. In neuronal and non-neuronal human cell lines, the disease-associated variants caused a mitochondrial phenotype of increased reactive oxygen species and reduced mitochondrial membrane potential, which were exacerbated upon proteolytic stress. These functional impairments correspond with characteristic alterations of the mitochondrial network in cells overexpressing mutant mortalin compared with wild-type (wt), which were confirmed in fibroblasts from a carrier of the A476T variant. In line with a loss of function hypothesis, knockdown of mortalin in human cells caused impaired mitochondrial function that was rescued by wt mortalin, but not by the variants. Our genetic and functional studies of novel disease-associated variants in the mortalin gene define a loss of mortalin function, which causes impaired mitochondrial function and dynamics. Our results support the role of this mitochondrial chaperone in neurodegeneration and underscore the concept of impaired mitochondrial protein quality control in PD. PMID:20817635

  12. DNA methylation status of nuclear-encoded mitochondrial genes underlies the tissue-dependent mitochondrial functions

    Directory of Open Access Journals (Sweden)

    Takasugi Masaki

    2010-08-01

    Full Text Available Abstract Background Mitochondria are semi-autonomous, semi-self-replicating organelles harboring their own DNA (mitochondrial DNA, mtDNA, and their dysregulation is involved in the development of various diseases. While mtDNA does not generally undergo epigenetic modifications, almost all mitochondrial proteins are encoded by nuclear DNA. However, the epigenetic regulation of nuclear-encoded mitochondrial genes (nuclear mt genes has not been comprehensively analyzed. Results We analyzed the DNA methylation status of 899 nuclear mt genes in the liver, brain, and heart tissues of mouse, and identified 636 nuclear mt genes carrying tissue-dependent and differentially methylated regions (T-DMRs. These nuclar mt genes are involved in various mitochondrial functions and they also include genes related to human diseases. T-DMRs regulate the expression of nuclear mt genes. Nuclear mt genes with tissue-specific hypomethylated T-DMRs were characterized by enrichment of the target genes of specific transcription factors such as FOXA2 in the liver, and CEBPA and STAT1 in the brain. Conclusions A substantial proportion of nuclear mt genes contained T-DMRs, and the DNA methylation status of numerous T-DMRs should underlie tissue-dependent mitochondrial functions.

  13. Impact of various exercise modalities on hepatic mitochondrial function.

    Science.gov (United States)

    Fletcher, Justin A; Meers, Grace M; Linden, Melissa A; Kearney, Monica L; Morris, E Matthew; Thyfault, John P; Rector, R Scott

    2014-06-01

    Hepatic mitochondrial adaptations to exercise are largely unknown. In this study, we sought to determine the effects of various exercise modalities on measures of hepatic mitochondrial function and metabolism. Male Sprague-Dawley rats were randomly assigned (n = 8-10 per group) into sedentary (SED), voluntary wheel running (VWR), VWR with food pulled during the dark cycle (VMR-OF), treadmill endurance exercise (TM-END; 30 m·min, 12% gradient, 60 min·d, 5 d·wk), or treadmill interval sprint training (TM-IST; 50 m·min, 12% gradient, 6 × 2.5 min bouts, 5 d·wk) groups for a 4-wk intervention. Hepatic mitochondrial state 3 and maximal uncoupled respiration were significantly (P < 0.05) increased in all four exercise groups compared with SED animals. In addition, hepatic mitochondrial [1-C] pyruvate oxidation to CO2, an index of pyruvate dehydrogenase (PDH) activity, was significantly increased in VWR-OF, TM-END, and TM-IST rats (P < 0.05), whereas exercise-induced increases in [2-C] pyruvate oxidation and [1-C] palmitate oxidation to CO2 did not reach statistical significance. Hepatic mitochondrial sirtuin 3 protein content, which putatively increases activity of mitochondrial proteins, was elevated in the VWR, VWR-OF, and TM-END groups (P < 0.05). In addition, only VWR-OF animals experienced increases in hepatic cytochrome c protein content and phosphoenolpyruvate carboxykinase mRNA, whereas PGC-1α mRNA expression and phospho-CREB protein content was increased in VWR-OF and TM-END groups. Four weeks of exercise training, regardless of exercise modality, significantly increased hepatic mitochondrial respiration and evoked other unique improvements in mitochondrial metabolism that do not appear to be dependent on increases in mitochondrial content.

  14. Borel functional calculus for quaternionic normal operators

    Science.gov (United States)

    Ramesh, G.; Santhosh Kumar, P.

    2017-05-01

    In this article, we give an approach to Borel functional calculus for quaternionic normal operators, which are not necessarily bounded. First, we establish the definition of functional calculus for a subclass of quaternion valued Borel functions, and then we extend the same to the class of quaternion valued Borel functions as well as L∞-functions. We also prove spectral mapping theorem as a consequence.

  15. Human 2'-phosphodiesterase localizes to the mitochondrial matrix with a putative function in mitochondrial RNA turnover

    DEFF Research Database (Denmark)

    Poulsen, Jesper Buchhave; Andersen, Kasper Røjkjær; Kjær, Karina Hansen

    2011-01-01

    . Interestingly, 2′-PDE shares both functionally and structurally characteristics with the CCR4-type exonuclease–endonuclease–phosphatase family of deadenylases. Here we show that 2′-PDE locates to the mitochondrial matrix of human cells, and comprise an active 3′–5′ exoribonuclease exhibiting a preference...... for oligo-adenosine RNA like canonical cytoplasmic deadenylases. Furthermore, we document a marked negative association between 2′-PDE and mitochondrial mRNA levels following siRNA-directed knockdown and plasmid-mediated overexpression, respectively. The results indicate that 2′-PDE, apart from playing...

  16. Normal Functions as a New Way of Defining Computable Functions

    Directory of Open Access Journals (Sweden)

    Leszek Dubiel

    2004-01-01

    Full Text Available Report sets new method of defining computable functions. This is formalization of traditional function descriptions, so it allows to define functions in very intuitive way. Discovery of Ackermann function proved that not all functions that can be easily computed can be so easily described with Hilbert's system of recursive functions. Normal functions lack this disadvantage.

  17. Normal Functions As A New Way Of Defining Computable Functions

    Directory of Open Access Journals (Sweden)

    Leszek Dubiel

    2004-01-01

    Full Text Available Report sets new method of defining computable functions. This is formalization of traditional function descriptions, so it allows to define functions in very intuitive way. Discovery of Ackermann function proved that not all functions that can be easily computed can be so easily described with Hilbert’s system of recursive functions. Normal functions lack this disadvantage.

  18. Apolipoprotein E4 (1–272 fragment is associated with mitochondrial proteins and affects mitochondrial function in neuronal cells

    Directory of Open Access Journals (Sweden)

    Michikawa Makoto

    2009-08-01

    Full Text Available Abstract Background Apolipoprotein E allele ε4 (apoE4 is a strong risk factor for developing Alzheimer's disease (AD. Secreted apoE has a critical function in redistributing lipids among central nervous system cells to maintain normal lipid homeostasis. In addition, previous reports have shown that apoE4 is cleaved by a protease in neurons to generate apoE4(1–272 fragment, which is associated with neurofibrillary tanglelike structures and mitochondria, causing mitochondrial dysfunction. However, it still remains unclear how the apoE fragment associates with mitochondria and induces mitochondrial dysfunction. Results To clarify the molecular mechanism, we carried out experiments to identify intracellular apoE-binding molecules and their functions in modulating mitochondria function. Here, we found that apoE4 binds to ubiquinol cytochrome c reductase core protein 2 (UQCRC2 and cytochrome C1, both of which are components of mitochondrial respiratory complex III, and cytochrome c oxidase subunit 4 isoform 1 (COX IV 1, which is a component of complex IV, in Neuro-2a cells. Interestingly, these proteins associated with apoE4(1–272 more strongly than intact apoE4(1–299. Further analysis showed that in Neuro-2a cells expressing apoE4(1–272, the enzymatic activities of mitochondrial respiratory complexes III and IV were significantly lower than those in Neuro-2a cells expressing apoE4(1–299. Conclusion ApoE4(1–272 fragment expressed in Neuro2a cells is associated with mitochondrial proteins, UQCRC2 and cytochrome C1, which are component of respiratory complex III, and with COX IV 1, which is a member of complex IV. Overexpression of apoE4(1–272 fragment impairs activities of complex III and IV. These results suggest that the C-terminal-truncated fragment of apoE4 binds to mitochondrial complexes and affects their activities, and thereby leading to neurodegeneration.

  19. Resveratrol Rescues Kidney Mitochondrial Function Following Hemorrhagic Shock.

    Science.gov (United States)

    Wang, Hao; Guan, Yuxia; Karamercan, Mehmet Akif; Ye, Lan; Bhatti, Tricia; Becker, Lance B; Baur, Joseph A; Sims, Carrie A

    2015-08-01

    Hemorrhagic shock may contribute to acute kidney injury (AKI) by profoundly altering renal mitochondrial function. Resveratrol (RSV), a naturally occurring sirtuin 1 (SIRT1) activator, has been shown to promote mitochondrial function and reduce oxidative damage in a variety of aging-related disease states. We hypothesized that RSV treatment during resuscitation would ameliorate kidney mitochondrial dysfunction and decrease oxidative damage following hemorrhagic shock. Using a decompensated hemorrhagic shock model, male Long-Evans rats (n = 6 per group) were killed prior to hemorrhage (sham), at severe shock, and following either lactated Ringer's (LR) resuscitation or LR + RSV resuscitation (RSV: 30 mg/kg). At each time point, blood samples were assayed for arterial blood gases, lactate, blood urea nitrogen, and serum creatinine. Mitochondria were also isolated from kidney samples in order to assess individual electron transport complexes (complexes I, II, and IV) using high-resolution respirometry. Total mitochondria reactive oxygen species were measured using fluorometry, and lipid peroxidation was assessed by measuring 4-hydroxynonenal by Western blot. Quantitative polymerase chain reaction was used quantify mRNA from peroxisome proliferator-activated receptor γ coactivator 1-α (PGC1-α) SIRT1, and proteins known to mitigate oxidative damage and promote mitochondrial biogenesis. Resveratrol supplementation during resuscitation restored mitochondrial respiratory capacity and decreased mitochondrial reactive oxygen species and lipid peroxidation. Compared with standard LR resuscitation, RSV treatment significantly increased SIRT1 and PGC1-α expression and significantly increased both superoxide dismutase 2 and catalase expression. Although RSV was associated with decreased lactate production, pH, blood urea nitrogen, and serum creatinine values did not differ between resuscitation strategies. Resuscitation with RSV significantly restored renal mitochondrial

  20. Cryopreservation of human skeletal muscle impairs mitochondrial function

    DEFF Research Database (Denmark)

    Larsen, Steen; Wright-Paradis, C; Gnaiger, E

    2012-01-01

    Previous studies have investigated if cryopreservation is a viable approach for functional mitochondrial analysis. Different tissues have been studied, and conflicting results have been published. The aim of the present study was to investigate if mitochondria in human skeletal muscle maintain...... functionality after long term cryopreservation (1 year). Skeletal muscle samples were preserved in dimethyl sulfoxide (DMSO) for later analysis. Human skeletal muscle fibres were thawed and permeabilised with saponin, and mitochondrial respiration was measured by high-resolution respirometry. The capacity...... of oxidative phosphorylation was significantly (P cryopreserved human skeletal muscle samples. Cryopreservation impaired respiration with substrates linked to Complex I more than for Complex II (P

  1. Cryopreservation of human skeletal muscle impairs mitochondrial function

    DEFF Research Database (Denmark)

    Larsen, Steen; Wright-Paradis, C; Gnaiger, E

    2012-01-01

    Previous studies have investigated if cryopreservation is a viable approach for functional mitochondrial analysis. Different tissues have been studied, and conflicting results have been published. The aim of the present study was to investigate if mitochondria in human skeletal muscle maintain...... functionality after long term cryopreservation (1 year). Skeletal muscle samples were preserved in dimethyl sulfoxide (DMSO) for later analysis. Human skeletal muscle fibres were thawed and permeabilised with saponin, and mitochondrial respiration was measured by high-resolution respirometry. The capacity...... of oxidative phosphorylation was significantly (P skeletal muscle samples. Cryopreservation impaired respiration with substrates linked to Complex I more than for Complex II (P

  2. Hepatic mitochondrial function analysis using needle liver biopsy samples.

    Directory of Open Access Journals (Sweden)

    Michael J J Chu

    Full Text Available BACKGROUNDS AND AIM: Current assessment of pre-operative liver function relies upon biochemical blood tests and histology but these only indirectly measure liver function. Mitochondrial function (MF analysis allows direct measurement of cellular metabolic function and may provide an additional index of hepatic health. Conventional MF analysis requires substantial tissue samples (>100 mg obtained at open surgery. Here we report a method to assess MF using <3 mg of tissue obtained by a Tru-cut® biopsy needle making it suitable for percutaneous application. METHODS: An 18G Bard® Max-core® biopsy instrument was used to collect samples. The optimal Tru-cut® sample weight, stability in ice-cold University of Wisconsin solution, reproducibility and protocol utility was initially evaluated in Wistar rat livers then confirmed in human samples. MF was measured in saponin-permeabilized samples using high-resolution respirometry. RESULTS: The average mass of a single rat and human liver Tru-cut® biopsy was 5.60±0.30 and 5.16±0.15 mg, respectively (mean; standard error of mean. Two milligram of sample was found the lowest feasible mass for the MF assay. Tissue MF declined after 1 hour of cold storage. Six replicate measurements within rats and humans (n = 6 each showed low coefficient of variation (<10% in measurements of State-III respiration, electron transport chain (ETC capacity and respiratory control ratio (RCR. Ischemic rat and human liver samples consistently showed lower State-III respiration, ETC capacity and RCR, compared to normal perfused liver samples. CONCLUSION: Consistent measurement of liver MF and detection of derangement in a disease state was successfully demonstrated using less than half the tissue from a single Tru-cut® biopsy. Using this technique outpatient assessment of liver MF is now feasible, providing a new assay for the evaluation of hepatic function.

  3. Mutant Parkin impairs mitochondrial function and morphology in human fibroblasts.

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    Anne Grünewald

    Full Text Available BACKGROUND: Mutations in Parkin are the most common cause of autosomal recessive Parkinson disease (PD. The mitochondrially localized E3 ubiquitin-protein ligase Parkin has been reported to be involved in respiratory chain function and mitochondrial dynamics. More recent publications also described a link between Parkin and mitophagy. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we investigated the impact of Parkin mutations on mitochondrial function and morphology in a human cellular model. Fibroblasts were obtained from three members of an Italian PD family with two mutations in Parkin (homozygous c.1072delT, homozygous delEx7, compound-heterozygous c.1072delT/delEx7, as well as from two relatives without mutations. Furthermore, three unrelated compound-heterozygous patients (delEx3-4/duplEx7-12, delEx4/c.924C>T and delEx1/c.924C>T and three unrelated age-matched controls were included. Fibroblasts were cultured under basal or paraquat-induced oxidative stress conditions. ATP synthesis rates and cellular levels were detected luminometrically. Activities of complexes I-IV and citrate synthase were measured spectrophotometrically in mitochondrial preparations or cell lysates. The mitochondrial membrane potential was measured with 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide. Oxidative stress levels were investigated with the OxyBlot technique. The mitochondrial network was investigated immunocytochemically and the degree of branching was determined with image processing methods. We observed a decrease in the production and overall concentration of ATP coinciding with increased mitochondrial mass in Parkin-mutant fibroblasts. After an oxidative insult, the membrane potential decreased in patient cells but not in controls. We further determined higher levels of oxidized proteins in the mutants both under basal and stress conditions. The degree of mitochondrial network branching was comparable in mutants and

  4. Changes in mitochondrial function and mitochondria associated protein expression in response to 2-weeks of high intensity interval training

    Directory of Open Access Journals (Sweden)

    Grace eVincent

    2015-02-01

    Full Text Available Purpose: High-intensity short-duration interval training (HIT stimulates functional and metabolic adaptation in skeletal muscle, but the influence of HIT on mitochondrial function remains poorly studied in humans. Mitochondrial metabolism, as well as mitochondrial-associated protein expression were tested in untrained participants performing HIT over a two-week period. Methods: Eight males performed a single-leg cycling protocol (12 x 1 min intervals at 120% peak power output, 90 s recovery, 4 days/week. Muscle biopsies (vastus lateralis were taken pre- and post-HIT. Mitochondrial respiration in permeabilized fibres, citrate synthase (CS activity and protein expression of peroxisome proliferator-activated receptor gamma coactivator (PGC-1α and respiratory complex components were measured. Results: HIT training improved peak power and time to fatigue. Increases in absolute oxidative phosphorylation (OXPHOS capacities and CS activity were observed, but not in the ratio of CCO to the electron transport system (CCO/ETS, the respiratory control ratios (RCR-1 and RCR-2 or mitochondrial-associated protein expression. Specific increases in OXPHOS flux were not apparent after normalization to CS, indicating that gross changes mainly resulted from increased mitochondrial mass. Conclusion: Over only 2 weeks HIT significantly increased mitochondrial function in skeletal muscle independently of detectable changes in mitochondrial-associated and mitogenic protein expression.

  5. [Normal aging of frontal lobe functions].

    Science.gov (United States)

    Calso, Cristina; Besnard, Jérémy; Allain, Philippe

    2016-03-01

    Normal aging in individuals is often associated with morphological, metabolic and cognitive changes, which particularly concern the cerebral frontal regions. Starting from the "frontal lobe hypothesis of cognitive aging" (West, 1996), the present review is based on the neuroanatomical model developed by Stuss (2008), introducing four categories of frontal lobe functions: executive control, behavioural and emotional self-regulation and decision-making, energization and meta-cognitive functions. The selected studies only address the changes of one at least of these functions. The results suggest a deterioration of several cognitive frontal abilities in normal aging: flexibility, inhibition, planning, verbal fluency, implicit decision-making, second-order and affective theory of mind. Normal aging seems also to be characterised by a general reduction in processing speed observed during neuropsychological assessment (Salthouse, 1996). Nevertheless many cognitive functions remain preserved such as automatic or non-conscious inhibition, specific capacities of flexibility and first-order theory of mind. Therefore normal aging doesn't seem to be associated with a global cognitive decline but rather with a selective change in some frontal systems, conclusion which should be taken into account for designing caring programs in normal aging.

  6. Towards non‐invasive monitoring of mitochondrial function

    NARCIS (Netherlands)

    F.A. Harms (Floor A.)

    2014-01-01

    markdownabstract__Abstract__ The work presented in this thesis describes the development of a non‐invasive and clinically usable system to monitor important aspects of mitochondrial function. This translational research project started with the validation of PpIX‐TSLT for cutaneous use in an

  7. Mitochondrial function in Müller cells - Does it matter?

    DEFF Research Database (Denmark)

    Toft-Kehler, Anne Katrine; Skytt, Dorte Marie; Svare, Alicia

    2017-01-01

    Growing evidence suggests that mitochondrial dysfunction might play a key role in the pathogenesis of age-related neurodegenerative inner retinal diseases such as diabetic retinopathy and glaucoma. Therefore, the present review provides a perspective on the impact of functional mitochondria...

  8. Nutritional support contributes to recuperation in a rat model of aplastic anemia by enhancing mitochondrial function.

    Science.gov (United States)

    Yang, Guang; Zhao, Lifen; Liu, Bing; Shan, Yujia; Li, Yang; Zhou, Huimin; Jia, Li

    2018-02-01

    Acquired aplastic anemia (AA) is a hematopoietic stem cell disease that leads to hematopoietic disorder and peripheral blood pancytopenia. We investigated whether nutritional support is helpful to AA recovery. We established a rat model with AA. A nutrient mixture was administered to rats with AA through different dose gavage once per day for 55 d. Animals in this study were assigned to one of five groups: normal control (NC; group includes normal rats); AA (rats with AA); high dose (AA + nutritional mixture, 2266.95 mg/kg/d); medium dose (1511.3 mg/kg/d); and low dose (1057.91 mg/kg/d). The effects of nutrition administration on general status and mitochondrial function of rats with AA were evaluated. The nutrient mixture with which the rats were supplemented significantly improved weight, peripheral blood parameters, and histologic parameters of rats with AA in a dose-dependent manner. Furthermore, we observed that the number of mitochondria in the liver, spleen, kidney, and brain was increased after supplementation by transmission electron microscopy analysis. Nutrient administration also improved mitochondrial DNA content, adenosine triphosphate content, and membrane potential but inhibited oxidative stress, thus, repairing the mitochondrial dysfunction of the rats with AA. Taken together, nutrition supplements may contribute to the improvement of mitochondrial function and play an important role in the recuperation of rats with AA. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Aim24 and MICOS modulate respiratory function, tafazzin-related cardiolipin modification and mitochondrial architecture

    OpenAIRE

    Harner, Max Emanuel; Unger, Ann-Katrin; Izawa, Toshiaki; Walther, Dirk M; Ozbalci, Cagakan; Geimer, Stefan; Reggiori, Fulvio; Brügger, Britta; Mann, Matthias; Westermann, Benedikt; Neupert, Walter; Reggiori, Fulvio

    2014-01-01

    Structure and function of mitochondria are intimately linked. In a search for components that participate in building the elaborate architecture of this complex organelle we have identified Aim24, an inner membrane protein. Aim24 interacts with the MICOS complex that is required for the formation of crista junctions and contact sites between inner and outer membranes. Aim24 is necessary for the integrity of the MICOS complex, for normal respiratory growth and mitochondrial ultrastructure. Mod...

  10. Diabetes and mitochondrial function: Role of hyperglycemia and oxidative stress

    International Nuclear Information System (INIS)

    Rolo, Anabela P.; Palmeira, Carlos M.

    2006-01-01

    Hyperglycemia resulting from uncontrolled glucose regulation is widely recognized as the causal link between diabetes and diabetic complications. Four major molecular mechanisms have been implicated in hyperglycemia-induced tissue damage: activation of protein kinase C (PKC) isoforms via de novo synthesis of the lipid second messenger diacylglycerol (DAG), increased hexosamine pathway flux, increased advanced glycation end product (AGE) formation, and increased polyol pathway flux. Hyperglycemia-induced overproduction of superoxide is the causal link between high glucose and the pathways responsible for hyperglycemic damage. In fact, diabetes is typically accompanied by increased production of free radicals and/or impaired antioxidant defense capabilities, indicating a central contribution for reactive oxygen species (ROS) in the onset, progression, and pathological consequences of diabetes. Besides oxidative stress, a growing body of evidence has demonstrated a link between various disturbances in mitochondrial functioning and type 2 diabetes. Mutations in mitochondrial DNA (mtDNA) and decreases in mtDNA copy number have been linked to the pathogenesis of type 2 diabetes. The study of the relationship of mtDNA to type 2 diabetes has revealed the influence of the mitochondria on nuclear-encoded glucose transporters, glucose-stimulated insulin secretion, and nuclear-encoded uncoupling proteins (UCPs) in β-cell glucose toxicity. This review focuses on a range of mitochondrial factors important in the pathogenesis of diabetes. We review the published literature regarding the direct effects of hyperglycemia on mitochondrial function and suggest the possibility of regulation of mitochondrial function at a transcriptional level in response to hyperglycemia. The main goal of this review is to include a fresh consideration of pathways involved in hyperglycemia-induced diabetic complications

  11. Mitochondrial quality control and communications with the nucleus are important in maintaining mitochondrial function and cell health.

    Science.gov (United States)

    Kotiadis, Vassilios N; Duchen, Michael R; Osellame, Laura D

    2014-04-01

    The maintenance of cell metabolism and homeostasis is a fundamental characteristic of living organisms. In eukaryotes, mitochondria are the cornerstone of these life supporting processes, playing leading roles in a host of core cellular functions, including energy transduction, metabolic and calcium signalling, and supporting roles in a number of biosynthetic pathways. The possession of a discrete mitochondrial genome dictates that the maintenance of mitochondrial 'fitness' requires quality control mechanisms which involve close communication with the nucleus. This review explores the synergistic mechanisms that control mitochondrial quality and function and ensure cellular bioenergetic homeostasis. These include antioxidant defence mechanisms that protect against oxidative damage caused by reactive oxygen species, while regulating signals transduced through such free radicals. Protein homeostasis controls import, folding, and degradation of proteins underpinned by mechanisms that regulate bioenergetic capacity through the mitochondrial unfolded protein response. Autophagic machinery is recruited for mitochondrial turnover through the process of mitophagy. Mitochondria also communicate with the nucleus to exact specific transcriptional responses through retrograde signalling pathways. The outcome of mitochondrial quality control is not only reliant on the efficient operation of the core homeostatic mechanisms but also in the effective interaction of mitochondria with other cellular components, namely the nucleus. Understanding mitochondrial quality control and the interactions between the organelle and the nucleus will be crucial in developing therapies for the plethora of diseases in which the pathophysiology is determined by mitochondrial dysfunction. This article is part of a Special Issue entitled Frontiers of Mitochondrial Research. © 2013. Published by Elsevier B.V. All rights reserved.

  12. Myoinositol: does it improve sperm mitochondrial function and sperm motility?

    Science.gov (United States)

    Condorelli, Rosita A; La Vignera, Sandro; Bellanca, Salvatore; Vicari, Enzo; Calogero, Aldo E

    2012-06-01

    To evaluate whether an improvement in mitochondrial membrane potential was associated with sperm motility amelioration and greater sperm recovery after the swim-up procedure. A second purpose was to evaluate the effects of myoinositol (MYO) on sperm apoptosis, quality of chromatin compaction, and DNA integrity. Spermatozoa from 20 normozoospermic men and 20 patients with oligo-astheno-teratozoospermia were incubated in vitro with 2 mg/mL of MYO or phosphate-buffered saline as a control for 2 hours. After this incubation period, sperm motility was evaluated. Flow cytometry was used to analyze the mitochondrial membrane potential, phosphatidylserine externalization, chromatin compactness, and DNA fragmentation. We also evaluated the total number of motile spermatozoa recovered after swim-up after incubation with MYO or phosphate-buffered saline. MYO significantly increased the percentage of spermatozoa with progressive motility in both normozoospermic men and patients with oligo-astheno-teratozoospermia. Motility improvement in the latter group was associated with a significant increase in the percentage of spermatozoa with high mitochondrial membrane potential. MYO had no effects on mitochondrial function in spermatozoa from normozoospermic men. Sperm phosphatidylserine externalization, chromatin compactness, and DNA fragmentation were unaffected by MYO in both groups. After incubation with MYO, the total number of spermatozoa recovered after swim-up had improved significantly in both groups. These data show that MYO increases sperm motility and the number of spermatozoa retrieved after swim-up in both normozoospermic men and patients with abnormal sperm parameters. In patients with oligo-astheno-teratozoospermia, the improvement in these parameters was associated with improved sperm mitochondrial function. These findings support the use of MYO in both in vivo- and in vitro-assisted reproductive techniques. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Impairment of striatal mitochondrial function by acute paraquat poisoning.

    Science.gov (United States)

    Czerniczyniec, Analía; Lanza, E M; Karadayian, A G; Bustamante, J; Lores-Arnaiz, S

    2015-10-01

    Mitochondria are essential for survival. Their primary function is to support aerobic respiration and to provide energy for intracellular metabolic pathways. Paraquat is a redox cycling agent capable of generating reactive oxygen species. The aim of the present study was to evaluate changes in cortical and striatal mitochondrial function in an experimental model of acute paraquat toxicity and to compare if the brain areas and the molecular mechanisms involved were similar to those observed after chronic exposure. Sprague-Dawley rats received paraquat (25 mg/Kg i.p.) or saline and were sacrificed after 24 h. Paraquat treatment decreased complex I and IV activity by 37 and 21 % respectively in striatal mitochondria. Paraquat inhibited striatal state 4 and state 3 KCN-sensitive respiration by 80 % and 62 % respectively, indicating a direct effect on respiratory chain. An increase of 2.2 fold in state 4 and 2.3 fold in state 3 in KCN-insensitive respiration was observed in striatal mitochondria from paraquat animals, suggesting that paraquat redox cycling also consumed oxygen. Paraquat treatment increased hydrogen peroxide production (150 %), TBARS production (42 %) and cardiolipin oxidation/depletion (12 %) in striatal mitochondria. Also, changes in mitochondrial polarization was induced after paraquat treatment. However, no changes were observed in any of these parameters in cortical mitochondria from paraquat treated-animals. These results suggest that paraquat treatment induced a clear striatal mitochondrial dysfunction due to both paraquat redox cycling reactions and impairment of the mitochondrial electron transport, causing oxidative damage. As a consequence, mitochondrial dysfunction could probably lead to alterations in cellular bioenergetics.

  14. Lower Mitochondrial Energy Production of the Thigh Muscles in Patients With Low-Normal Ankle-Brachial Index.

    Science.gov (United States)

    AlGhatrif, Majd; Zane, Ariel; Oberdier, Matt; Canepa, Marco; Studenski, Stephanie; Simonsick, Eleanor; Spencer, Richard G; Fishbein, Kenneth; Reiter, David; Lakatta, Edward G; McDermott, Mary M; Ferrucci, Luigi

    2017-08-30

    Lower muscle mitochondrial energy production may contribute to impaired walking endurance in patients with peripheral arterial disease. A borderline ankle-brachial index (ABI) of 0.91 to 1.10 is associated with poorer walking endurance compared with higher ABI. We hypothesized that in the absence of peripheral arterial disease, lower ABI is associated with lower mitochondrial energy production. We examined 363 men and women participating in the Baltimore Longitudinal Study of Aging with an ABI between 0.90 and 1.40. Muscle mitochondrial energy production was assessed by post-exercise phosphocreatine recovery rate constant ( k PCr) measured by phosphorus magnetic resonance spectroscopy of the left thigh. A lower post-exercise phosphocreatine recovery rate constant reflects decreased mitochondria energy production.The mean age of the participants was 71±12 years. A total of 18.4% had diabetes mellitus and 4% were current and 40% were former smokers. Compared with participants with an ABI of 1.11 to 1.40, those with an ABI of 0.90 to 1.10 had significantly lower post-exercise phosphocreatine recovery rate constant (19.3 versus 20.8 ms -1 , P =0.015). This difference remained significant after adjusting for age, sex, race, smoking status, diabetes mellitus, body mass index, and cholesterol levels ( P =0.028). Similarly, post-exercise phosphocreatine recovery rate constant was linearly associated with ABI as a continuous variable, both in the ABI ranges of 0.90 to 1.40 (standardized coefficient=0.15, P =0.003) and 1.1 to 1.4 (standardized coefficient=0.12, P =0.0405). An ABI of 0.90 to 1.10 is associated with lower mitochondrial energy production compared with an ABI of 1.11 to 1.40. These data demonstrate adverse associations of lower ABI values with impaired mitochondrial activity even within the range of a clinically accepted definition of a normal ABI. Further study is needed to determine whether interventions in persons with ABIs of 0.90 to 1.10 can prevent

  15. Effects of peroxisomal catalase inhibition on mitochondrial function.

    Directory of Open Access Journals (Sweden)

    Paul eWalton

    2012-04-01

    Full Text Available Peroxisomes produce hydrogen peroxide as a metabolic by-product of their many oxidase enzymes, but contain catalase that breaks down hydrogen peroxide in order to maintain the organelle’s oxidative balance. It has been previously demonstrated that, as cells age, catalase is increasingly absent from the peroxisome, and resides instead as an unimported tetrameric molecule in the cell cytosol; an alteration that is coincident with increased cellular hydrogen peroxide levels. As this process begins in middle-passage cells, we sought to determine whether peroxisomal hydrogen peroxide could contribute to the oxidative damage observed in mitochondria in late-passage cells. Early-passage human fibroblasts (Hs27 treated with aminotriazole (3-AT, an irreversible catalase inhibitor, demonstrated decreased catalase activity, increased levels of cellular hydrogen peroxide, protein carbonyls, and peroxisomal numbers. This treatment increased mitochondrial ROS levels, and decreased the mitochondrial aconitase activity by approximately 85% within 24 hours. In addition, mitochondria from 3-AT treated cells show a decrease in inner membrane potential. These results demonstrate that peroxisome-derived oxidative imbalance may rapidly impair mitochondrial function, and considering that peroxisomal oxidative imbalance begins to occur in middle-passage cells, supports the hypothesis that peroxisomal oxidant release occurs upstream of, and contributes to, the mitochondrial damage observed in aging cells.

  16. Effects of peroxisomal catalase inhibition on mitochondrial function.

    Science.gov (United States)

    Walton, Paul A; Pizzitelli, Michael

    2012-01-01

    Peroxisomes produce hydrogen peroxide as a metabolic by-product of their many oxidase enzymes, but contain catalase that breaks down hydrogen peroxide in order to maintain the organelle's oxidative balance. It has been previously demonstrated that, as cells age, catalase is increasingly absent from the peroxisome, and resides instead as an unimported tetrameric molecule in the cell cytosol; an alteration that is coincident with increased cellular hydrogen peroxide levels. As this process begins in middle-passage cells, we sought to determine whether peroxisomal hydrogen peroxide could contribute to the oxidative damage observed in mitochondria in late-passage cells. Early-passage human fibroblasts (Hs27) treated with aminotriazole (3-AT), an irreversible catalase inhibitor, demonstrated decreased catalase activity, increased levels of cellular hydrogen peroxide, protein carbonyls, and peroxisomal numbers. This treatment increased mitochondrial reactive oxygen species levels, and decreased the mitochondrial aconitase activity by ∼85% within 24 h. In addition, mitochondria from 3-AT treated cells show a decrease in inner membrane potential. These results demonstrate that peroxisome-derived oxidative imbalance may rapidly impair mitochondrial function, and considering that peroxisomal oxidative imbalance begins to occur in middle-passage cells, supports the hypothesis that peroxisomal oxidant release occurs upstream of, and contributes to, the mitochondrial damage observed in aging cells.

  17. Alternative mitochondrial functions in cell physiopathology: beyond ATP production

    Directory of Open Access Journals (Sweden)

    Kowaltowski A.J.

    2000-01-01

    Full Text Available It is well known that mitochondria are the main site for ATP generation within most tissues. However, mitochondria also participate in a surprising number of alternative activities, including intracellular Ca2+ regulation, thermogenesis and the control of apoptosis. In addition, mitochondria are the main cellular generators of reactive oxygen species, and may trigger necrotic cell death under conditions of oxidative stress. This review concentrates on these alternative mitochondrial functions, and their role in cell physiopathology.

  18. Platelet mitochondrial function and dysfunction: physiological consequences

    Energy Technology Data Exchange (ETDEWEB)

    Popov, D.

    2015-07-01

    There is a general trend in revisiting mitochondria using the up-to-date technologies that uncovered novel attributes of this organelle, such as the intracellular displacement to locations where an energy supply is needed, the dynamic shape changes and turnover, the initiation of signaling to the rest of the cell, and the ability to crosstalk with other cellular organelles. The in-depth scrutiny of platelet mitochondria role in health and pathology is included within this ongoing revisiting trend. The current article puts into a nutshell the most recent data on platelet mitochondria function and disease-related ion, focusing on generation of stress- and apoptosis-related signaling molecules, overproduction of reactive oxygen species during activation and disease, on the biomarker potential of platelets mitochondria, and their prospective exploitation in translational applications. These novel findings complete the physiological profile of platelets and could have potential therapeutic effectiveness in platelet-associated disorders.

  19. Improving Mitochondrial Function Protects Bumblebees from Neonicotinoid Pesticides.

    Directory of Open Access Journals (Sweden)

    Michael B Powner

    Full Text Available Global pollination is threatened by declining insect pollinator populations that may be linked to neonicotinoid pesticide use. Neonicotinoids over stimulate neurons and depolarize their mitochondria, producing immobility and death. However, mitochondrial function can be improved by near infrared light absorbed by cytochrome c oxidase in mitochondrial respiration. In flies, daily exposure to 670nm light throughout life increases average lifespan and aged mobility, and reduces systemic inflammation. Here we treat bumble bees with Imidacloprid a common neonicotinoid. This undermined ATP and rapidly induced immobility and reduced visual function and survival. Bees exposed to insecticide and daily to 670nm light showed corrected ATP levels and significantly improved mobility allowing them to feed. Physiological recordings from eyes revealed that light exposure corrected deficits induced by the pesticide. Overall, death rates in bees exposed to insecticide but also given 670nm light were indistinguishable from controls. When Imidacloprid and light exposure were withdrawn, survival was maintained. Bees and insects generally cannot see deep red light so it does not disturb their behaviour. Hence, we show that deep red light exposure that improves mitochondrial function, reverses the sensory and motor deficits induced by Imidacloprid. These results may have important implications as light delivery is economic and can be placed in hives/colonies.

  20. Quercetin Affects Erythropoiesis and Heart Mitochondrial Function in Mice

    Directory of Open Access Journals (Sweden)

    Lina M. Ruiz

    2015-01-01

    Full Text Available Quercetin, a dietary flavonoid used as a food supplement, showed powerful antioxidant effects in different cellular models. However, recent in vitro and in vivo studies in mammals have suggested a prooxidant effect of quercetin and described an interaction with mitochondria causing an increase in O2∙- production, a decrease in ATP levels, and impairment of respiratory chain in liver tissue. Therefore, because of its dual actions, we studied the effect of quercetin in vivo to analyze heart mitochondrial function and erythropoiesis. Mice were injected with 50 mg/kg of quercetin for 15 days. Treatment with quercetin decreased body weight, serum insulin, and ceruloplasmin levels as compared with untreated mice. Along with an impaired antioxidant capacity in plasma, quercetin-treated mice showed a significant delay on erythropoiesis progression. Heart mitochondrial function was also impaired displaying more protein oxidation and less activity for IV, respectively, than no-treated mice. In addition, a significant reduction in the protein expression levels of Mitofusin 2 and Voltage-Dependent Anion Carrier was observed. All these results suggest that quercetin affects erythropoiesis and mitochondrial function and then its potential use as a dietary supplement should be reexamined.

  1. Reye's syndrome: salicylate and mitochondrial monoamine oxidase function

    International Nuclear Information System (INIS)

    Faraj, B.A.; Caplan, D.; Lolies, P.

    1986-01-01

    It has been suggested that aspirin is somehow linked with the onset of Reye's syndrome (RS). A general feature of Reye's syndrome is severe impairment of mitochondrial monoamine oxidase (MAO) function. The main objective of this investigation was to study the effect of salicylate on platelet mitochondrial MAO activity in three groups: group A (healthy children, n = 21) and group C (healthy adults, n = 10). Platelet MAO was measured by radio-enzymatic technique with 14 C-tyramine as a substrate. The results showed that salicyclate (10 mM) had a 20 to 60 percent inhibitory effect on platelet MAO function in only 1, 3 and 2 of the subjects in group A, B and C. Furthermore, there was an association between low enzyme activity and salicylate MAO inhibitory effect in these subjects. These preliminary findings suggest that salicylate may induce deterioration in mitochondrial function in susceptible individuals and that the assessment of salicylate MAO inhibitory effect may identify those who may be at risk to develop aspirin poisoning and Reye's syndrome

  2. Aim24 and MICOS modulate respiratory function, tafazzin-related cardiolipin modification and mitochondrial architecture.

    Science.gov (United States)

    Harner, Max Emanuel; Unger, Ann-Katrin; Izawa, Toshiaki; Walther, Dirk M; Ozbalci, Cagakan; Geimer, Stefan; Reggiori, Fulvio; Brügger, Britta; Mann, Matthias; Westermann, Benedikt; Neupert, Walter

    2014-01-01

    Structure and function of mitochondria are intimately linked. In a search for components that participate in building the elaborate architecture of this complex organelle we have identified Aim24, an inner membrane protein. Aim24 interacts with the MICOS complex that is required for the formation of crista junctions and contact sites between inner and outer membranes. Aim24 is necessary for the integrity of the MICOS complex, for normal respiratory growth and mitochondrial ultrastructure. Modification of MICOS subunits Mic12 or Mic26 by His-tags in the absence of Aim24 leads to complete loss of cristae and respiratory complexes. In addition, the level of tafazzin, a cardiolipin transacylase, is drastically reduced and the composition of cardiolipin is modified like in mutants lacking tafazzin. In conclusion, Aim24 by interacting with the MICOS complex plays a key role in mitochondrial architecture, composition and function. DOI: http://dx.doi.org/10.7554/eLife.01684.001.

  3. The mitochondrial transcription factor A functions in mitochondrial base excision repair

    DEFF Research Database (Denmark)

    Canugovi, Chandrika; Maynard, Scott; Bayne, Anne-Cécile V

    2010-01-01

    in mitochondria, whereas base excision repair (BER) has been comprehensively characterized in these organelles. The BER proteins are associated with the inner membrane in mitochondria and thus with the mitochondrial nucleoid, where TFAM is also situated. However, a function for TFAM in BER has not yet been...... with and alter the DNA binding activity of TFAM, alleviates TFAM-induced inhibition of BER proteins. Together, the results suggest that TFAM modulates BER in mitochondria by virtue of its DNA binding activity and protein interactions....

  4. Cognitive functions and normal tension glaucoma.

    Science.gov (United States)

    Daveckaite, Akvile; Grusauskiene, Evelina; Petrikonis, Kestutis; Vaitkus, Antanas; Siaudvytyte, Lina; Januleviciene, Ingrida

    2017-10-01

    Only a few studies have analyzed the potential link between glaucoma and cognitive function impairment. They have found controversial results. This study aims to perform quick cognitive function assessment with clock drawing test (CDT) using two different scoring systems and compare between normal tension glaucoma (NTG) and cataract patients. Totally, 30 NTG and 30 patients with cataracts were included in a prospective, pilot study. The predrawn circle was given, and patients were asked to draw the clock showing a time of 11:10. The test was evaluated using two methods - Freund method using a 7-point scoring scale (optimal cutoff ≤4) and Rakusa using a 4-point scoring scale (optimal cutoff ≤3). The level of significance was set at P drawing. Further prospective studies are needed to investigate the CDT reliability as fast screening test of cognitive function impairment in glaucoma patients.

  5. Normal erect swallowing. Normal function and incidence of variations.

    Science.gov (United States)

    Curtis, D J; Cruess, D F; Dachman, A H

    1985-10-01

    Of 871 candidates presenting for upper gastrointestinal examinations, 16 met the rigorous criteria established for selecting asymptomatic normal volunteers. Frame-by-frame evaluation of their videorecorded pharyngeal swallow confirmed many observations made previously utilizing cine recording at much higher radiation dosages. In addition, new observations were made: the nasopharynx may not occlude until the bolus is entirely within the pharynx; air mixes with the bolus if the swallow is an "open" type; the epiglottis always inverts in normal individuals regardless of the type of swallow ("open," air filled oro-and hypopharynx into which the swallowed bolus is dropped; "closed," airless oropharynx into which the swallowed bolus is pushed by a continuous peristaltic drive of the tongue and palate, thus reconstituting the pharyngeal space); laryngeal descent may aid in stripping the bolus from the pharynx; the vestibule may not completely close during the swallow and the larynx can still be impervious to the bolus; the peristaltic wave does not begin until the bolus has breeched the cricopharyngeus; the cricopharyngeus may be seen frequently in normal individuals, but does not delay the passage of the bolus; asymmetric flow of the bolus around the larynx is common and may not be the result of epiglottic tilt or head positioning.

  6. Mitochondrial function and toxicity: role of the B vitamin family on mitochondrial energy metabolism.

    Science.gov (United States)

    Depeint, Flore; Bruce, W Robert; Shangari, Nandita; Mehta, Rhea; O'Brien, Peter J

    2006-10-27

    The B vitamins are water-soluble vitamins required as coenzymes for enzymes essential for cell function. This review focuses on their essential role in maintaining mitochondrial function and on how mitochondria are compromised by a deficiency of any B vitamin. Thiamin (B1) is essential for the oxidative decarboxylation of the multienzyme branched-chain ketoacid dehydrogenase complexes of the citric acid cycle. Riboflavin (B2) is required for the flavoenzymes of the respiratory chain, while NADH is synthesized from niacin (B3) and is required to supply protons for oxidative phosphorylation. Pantothenic acid (B5) is required for coenzyme A formation and is also essential for alpha-ketoglutarate and pyruvate dehydrogenase complexes as well as fatty acid oxidation. Biotin (B7) is the coenzyme of decarboxylases required for gluconeogenesis and fatty acid oxidation. Pyridoxal (B6), folate and cobalamin (B12) properties are reviewed elsewhere in this issue. The experimental animal and clinical evidence that vitamin B therapy alleviates B deficiency symptoms and prevents mitochondrial toxicity is also reviewed. The effectiveness of B vitamins as antioxidants preventing oxidative stress toxicity is also reviewed.

  7. TCA Cycle and Mitochondrial Membrane Potential Are Necessary for Diverse Biological Functions.

    Science.gov (United States)

    Martínez-Reyes, Inmaculada; Diebold, Lauren P; Kong, Hyewon; Schieber, Michael; Huang, He; Hensley, Christopher T; Mehta, Manan M; Wang, Tianyuan; Santos, Janine H; Woychik, Richard; Dufour, Eric; Spelbrink, Johannes N; Weinberg, Samuel E; Zhao, Yingming; DeBerardinis, Ralph J; Chandel, Navdeep S

    2016-01-21

    Mitochondrial metabolism is necessary for the maintenance of oxidative TCA cycle function and mitochondrial membrane potential. Previous attempts to decipher whether mitochondria are necessary for biological outcomes have been hampered by genetic and pharmacologic methods that simultaneously disrupt multiple functions linked to mitochondrial metabolism. Here, we report that inducible depletion of mitochondrial DNA (ρ(ο) cells) diminished respiration, oxidative TCA cycle function, and the mitochondrial membrane potential, resulting in diminished cell proliferation, hypoxic activation of HIF-1, and specific histone acetylation marks. Genetic reconstitution only of the oxidative TCA cycle function specifically in these inducible ρ(ο) cells restored metabolites, resulting in re-establishment of histone acetylation. In contrast, genetic reconstitution of the mitochondrial membrane potential restored ROS, which were necessary for hypoxic activation of HIF-1 and cell proliferation. These results indicate that distinct mitochondrial functions associated with respiration are necessary for cell proliferation, epigenetics, and HIF-1 activation. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Undiminished mitochondrial function during stunning in rabbit heart at 28 degrees C

    NARCIS (Netherlands)

    Zuurbier, C. J.; van Beek, J. H.

    1997-01-01

    To investigate effect of brief ischemia on mitochondrial function in intact myocardium, rather than in isolated mitochondria. The mitochondrial response was characterized by the mean response time (tmito) of cardiac mitochondrial O2 consumption to steps in heart rate. Isolated isovolumic rabbit

  9. The Brain Renin-Angiotensin System and Mitochondrial Function: Influence on Blood Pressure and Baroreflex in Transgenic Rat Strains

    Directory of Open Access Journals (Sweden)

    Manisha Nautiyal

    2013-01-01

    Full Text Available Mitochondrial dysfunction is implicated in many cardiovascular diseases, including hypertension, and may be associated with an overactive renin-angiotensin system (RAS. Angiotensin (Ang II, a potent vasoconstrictor hormone of the RAS, also impairs baroreflex and mitochondrial function. Most deleterious cardiovascular actions of Ang II are thought to be mediated by NADPH-oxidase- (NOX- derived reactive oxygen species (ROS that may also stimulate mitochondrial oxidant release and alter redox-sensitive signaling pathways in the brain. Within the RAS, the actions of Ang II are counterbalanced by Ang-(1–7, a vasodilatory peptide known to mitigate against increased oxidant stress. A balance between Ang II and Ang-(1–7 within the brain dorsal medulla contributes to maintenance of normal blood pressure and proper functioning of the arterial baroreceptor reflex for control of heart rate. We propose that Ang-(1–7 may negatively regulate the redox signaling pathways activated by Ang II to maintain normal blood pressure, baroreflex, and mitochondrial function through attenuating ROS (NOX-generated and/or mitochondrial.

  10. Pre-ischemic mitochondrial substrate constraint by inhibition of malate-aspartate shuttle preserves mitochondrial function after ischemia-reperfusion

    DEFF Research Database (Denmark)

    Jespersen, Nichlas Riise; Yokota, Takashi; Støttrup, Nicolaj Brejnholt

    2017-01-01

    effects of MAS inhibition on the mitochondria were similar to those of IPC. Intriguingly, the protection of mitochondrial function by AOA treatment appears to be different from that of IPC because AOA treatment, but not IPC, downregulated myocardial tricarboxilic acid (TCA)-cycle intermediates...... at the onset of reperfusion. MAS inhibition thus preserved mitochondrial respiratory capacity and decreased mitochondrial oxidative stress during late reperfusion in the IR-injured heart, at least in part, via metabolic regulation of TCA cycle intermediates in the mitochondria at the onset of reperfusion....

  11. The efficiency of functional mitochondrial replacement in Saccharomyces species has directional character

    DEFF Research Database (Denmark)

    Sulo, P.; Spirek, M.; Soltesova, A.

    2003-01-01

    Optimal interactions among nuclear and mitochondria-coded proteins are required to assemble functional complexes of mitochondrial oxidative phosphorylation. The communication between the nuclear and mitochondrial genomes has been studied by transplacement of mitochondria from related species...... in the S. cerevisiae mitochondrial DNA. Our results suggest that, apart from evolutionary distance, the direction of mitochondrial replacement could play a significant role in installing the complete (wild-type-like) interaction between mitochondria and nuclei from different species....

  12. The urinary proteome and metabonome differ from normal in adults with mitochondrial disease.

    Science.gov (United States)

    Hall, Andrew M; Vilasi, Annalisa; Garcia-Perez, Isabel; Lapsley, Marta; Alston, Charlotte L; Pitceathly, Robert D S; McFarland, Robert; Schaefer, Andrew M; Turnbull, Doug M; Beaumont, Nick J; Hsuan, Justin J; Cutillas, Pedro R; Lindon, John C; Holmes, Elaine; Unwin, Robert J; Taylor, Robert W; Gorman, Grainne S; Rahman, Shamima; Hanna, Michael G

    2015-03-01

    We studied the extent and nature of renal involvement in a cohort of 117 adult patients with mitochondrial disease, by measuring urinary retinol-binding protein (RBP) and albumin; established markers of tubular and glomerular dysfunction, respectively. Seventy-five patients had the m.3243A>G mutation and the most frequent phenotypes within the entire cohort were 14 with MELAS, 33 with MIDD, and 17 with MERRF. Urinary RBP was increased in 29 of 75 of m.3243A>G patients, whereas albumin was increased in 23 of the 75. The corresponding numbers were 16 and 14, respectively, in the 42 non-m.3243A>G patients. RBP and albumin were higher in diabetic m.3243A>G patients than in nondiabetics, but there were no significant differences across the three major clinical phenotypes. The urine proteome (mass spectrometry) and metabonome (nuclear magnetic resonance) in a subset of the m.3243A>G patients were markedly different from controls, with the most significant alterations occurring in lysosomal proteins, calcium-binding proteins, and antioxidant defenses. Differences were also found between asymptomatic m.3243A>G carriers and controls. No patients had an elevated serum creatinine level, but 14% had hyponatremia, 10% had hypophosphatemia, and 14% had hypomagnesemia. Thus, abnormalities in kidney function are common in adults with mitochondrial disease, exist in the absence of elevated serum creatinine, and are not solely explained by diabetes.

  13. Endocannabinoids in neuroendopsychology: multiphasic control of mitochondrial function

    Science.gov (United States)

    Nunn, Alistair; Guy, Geoffrey; Bell, Jimmy D.

    2012-01-01

    The endocannabinoid system (ECS) is a construct based on the discovery of receptors that are modulated by the plant compound tetrahydrocannabinol and the subsequent identification of a family of nascent ligands, the ‘endocannabinoids’. The function of the ECS is thus defined by modulation of these receptors—in particular, by two of the best-described ligands (2-arachidonyl glycerol and anandamide), and by their metabolic pathways. Endocannabinoids are released by cell stress, and promote both cell survival and death according to concentration. The ECS appears to shift the immune system towards a type 2 response, while maintaining a positive energy balance and reducing anxiety. It may therefore be important in resolution of injury and inflammation. Data suggest that the ECS could potentially modulate mitochondrial function by several different pathways; this may help explain its actions in the central nervous system. Dose-related control of mitochondrial function could therefore provide an insight into its role in health and disease, and why it might have its own pathology, and possibly, new therapeutic directions. PMID:23108551

  14. Cognitive functions and normal tension glaucoma

    Directory of Open Access Journals (Sweden)

    Akvile Daveckaite

    2017-01-01

    Full Text Available Purpose: Only a few studies have analyzed the potential link between glaucoma and cognitive function impairment. They have found controversial results. This study aims to perform quick cognitive function assessment with clock drawing test (CDT using two different scoring systems and compare between normal tension glaucoma (NTG and cataract patients. Methods: Totally, 30 NTG and 30 patients with cataracts were included in a prospective, pilot study. The predrawn circle was given, and patients were asked to draw the clock showing a time of 11:10. The test was evaluated using two methods – Freund method using a 7-point scoring scale (optimal cutoff ≤4 and Rakusa using a 4-point scoring scale (optimal cutoff ≤3. The level of significance was set at P < 0.05. Results: CDT result was significantly better in cataract group than in NTG group: 3.5 (2 versus 2 (2 by Freund, (P = 0.003 and 6.5 (1 versus 4.5 (2.75 by Rakusa, respectively (P = 0.004. Sixty percent (n = 18 of NTG group and 10% (n = 3 of cataract group patients completed the CDT in the specific picture manner (the short hand on 11 and the long hand between 11 and 12, (P = 0.001. Conclusions: Lower CDT results were seen in NTG patients according to two different scoring systems. NTG patients showed a specific manner of drawing. Further prospective studies are needed to investigate the CDT reliability as fast screening test of cognitive function impairment in glaucoma patients.

  15. Normal Function of the Colon and Anorectal Area

    Science.gov (United States)

    ... IFFGD What is Constipation Introduction: What is Constipation? Normal Function Common Questions & Mistaken Beliefs Signs & Symptoms Symptoms ... IFFGD What is Constipation Introduction: What is Constipation? Normal Function Common Questions & Mistaken Beliefs Signs & Symptoms Symptoms ...

  16. Metformin-treated patients with type 2 diabetes have normal mitochondrial complex I respiration

    DEFF Research Database (Denmark)

    Larsen, Steen; Rabøl, R; Hansen, C N

    2012-01-01

    The glucose-lowering drug metformin has been shown to inhibit complex I of the mitochondrial electron transport chain in skeletal muscle. To investigate this effect in vivo we studied skeletal muscle mitochondrial respiratory capacity and content from patients with type 2 diabetes treated...

  17. Arabidopsis mTERF15 is required for mitochondrial nad2 intron 3 splicing and functional complex I activity.

    Directory of Open Access Journals (Sweden)

    Ya-Wen Hsu

    Full Text Available Mitochondria play a pivotal role in most eukaryotic cells, as they are responsible for the generation of energy and diverse metabolic intermediates for many cellular events. During endosymbiosis, approximately 99% of the genes encoded by the mitochondrial genome were transferred into the host nucleus, and mitochondria import more than 1000 nuclear-encoded proteins from the cytosol to maintain structural integrity and fundamental functions, including DNA replication, mRNA transcription and RNA metabolism of dozens of mitochondrial genes. In metazoans, a family of nuclear-encoded proteins called the mitochondrial transcription termination factors (mTERFs regulates mitochondrial transcription, including transcriptional termination and initiation, via their DNA-binding activities, and the dysfunction of individual mTERF members causes severe developmental defects. Arabidopsis thaliana and Oryza sativa contain 35 and 48 mTERFs, respectively, but the biological functions of only a few of these proteins have been explored. Here, we investigated the biological role and molecular mechanism of Arabidopsis mTERF15 in plant organelle metabolism using molecular genetics, cytological and biochemical approaches. The null homozygous T-DNA mutant of mTERF15, mterf15, was found to result in substantial retardation of both vegetative and reproductive development, which was fully complemented by the wild-type genomic sequence. Surprisingly, mitochondria-localized mTERF15 lacks obvious DNA-binding activity but processes mitochondrial nad2 intron 3 splicing through its RNA-binding ability. Impairment of this splicing event not only disrupted mitochondrial structure but also abolished the activity of mitochondrial respiratory chain complex I. These effects are in agreement with the severe phenotype of the mterf15 homozygous mutant. Our study suggests that Arabidopsis mTERF15 functions as a splicing factor for nad2 intron 3 splicing in mitochondria, which is essential

  18. Naked mole-rats maintain healthy skeletal muscle and Complex IV mitochondrial enzyme function into old age.

    Science.gov (United States)

    Stoll, Elizabeth A; Karapavlovic, Nevena; Rosa, Hannah; Woodmass, Michael; Rygiel, Karolina; White, Kathryn; Turnbull, Douglass M; Faulkes, Chris G

    2016-12-19

    The naked mole-rat (NMR) Heterocephalus glaber is an exceptionally long-lived rodent, living up to 32 years in captivity. This extended lifespan is accompanied by a phenotype of negligible senescence, a phenomenon of very slow changes in the expected physiological characteristics with age. One of the many consequences of normal aging in mammals is the devastating and progressive loss of skeletal muscle, termed sarcopenia, caused in part by respiratory enzyme dysfunction within the mitochondria of skeletal muscle fibers. Here we report that NMRs avoid sarcopenia for decades. Muscle fiber integrity and mitochondrial ultrastructure are largely maintained in aged animals. While mitochondrial Complex IV expression and activity remains stable, Complex I expression is significantly decreased. We show that aged naked mole-rat skeletal muscle tissue contains some mitochondrial DNA rearrangements, although the common mitochondrial DNA deletions associated with aging in human and other rodent skeletal muscles are not present. Interestingly, NMR skeletal muscle fibers demonstrate a significant increase in mitochondrial DNA copy number. These results have intriguing implications for the role of mitochondria in aging, suggesting Complex IV, but not Complex I, function is maintained in the long-lived naked mole rat, where sarcopenia is avoided and healthy muscle function is maintained for decades.

  19. Decreased endothelial nitric oxide synthase expression and function contribute to impaired mitochondrial biogenesis and oxidative stress in fetal lambs with persistent pulmonary hypertension

    OpenAIRE

    Afolayan, Adeleye J.; Eis, Annie; Alexander, Maxwell; Michalkiewicz, Teresa; Teng, Ru-Jeng; Lakshminrusimha, Satyan; Konduri, Girija G.

    2015-01-01

    Impaired vasodilation in persistent pulmonary hypertension of the newborn (PPHN) is characterized by mitochondrial dysfunction. We investigated the hypothesis that a decreased endothelial nitric oxide synthase level leads to impaired mitochondrial biogenesis and function in a lamb model of PPHN induced by prenatal ductus arteriosus constriction. We ventilated PPHN lambs with 100% O2 alone or with inhaled nitric oxide (iNO). We treated pulmonary artery endothelial cells (PAECs) from normal and...

  20. Evaluation of ubiquinone concentration and mitochondrial function relative to cerivastatin-induced skeletal myopathy in rats

    International Nuclear Information System (INIS)

    Schaefer, William H.; Lawrence, Jeffery W.; Loughlin, Amy F.; Stoffregen, Dana A.; Mixson, Lori A.; Dean, Dennis C.; Raab, Conrad E.; Yu, Nathan X.; Lankas, George R.; Frederick, Clay B.

    2004-01-01

    As a class, hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors can potentially cause skeletal myopathy. One statin, cerivastatin, has recently been withdrawn from the market due to an unacceptably high incidence of rhabdomyolysis. The mechanism underlying statin-induced myopathy is unknown. This paper sought to investigate the relationship among statin-induced myopathy, mitochondrial function, and muscle ubiquinone levels. Rats were administered cerivastatin at 0.1, 0.5, and 1.0 (mg/kg)/day or dose vehicle (controls) by oral gavage for 15 days. Samples of type I-predominant skeletal muscle (soleus) and type II-predominant skeletal muscle [quadriceps and extensor digitorum longus (EDL)], and blood were collected on study days 5, 10, and 15 for morphological evaluation, clinical chemistry, mitochondrial function tests, and analysis of ubiquinone levels. No histological changes were observed in any of the animals on study days 5 or 10, but on study day 15, mid- and high-dose animals had necrosis and inflammation in type II skeletal muscle. Elevated creatine kinase (CK) levels in blood (a clinical marker of myopathy) correlated with the histopathological diagnosis of myopathy. Ultrastructural characterization of skeletal muscle revealed disruption of the sarcomere and altered mitochondria only in myofibers with degeneration, while adjacent myofibers were unaffected and had normal mitochondria. Thus, mitochondrial effects appeared not to precede myofiber degeneration. Mean coenzyme Q9 (CoQ9) levels in all dose groups were slightly decreased relative to controls in type II skeletal muscle, although the difference was not significantly different in most cases. Mitochondrial function in skeletal muscle was not affected by the changes in ubiquinone levels. The ubiquinone levels in high-dose-treated animals exhibiting myopathy were not significantly different from low-dose animals with no observable toxic effects. Furthermore, ubiquinone levels did not correlate

  1. Ribosome profiling reveals features of normal and disease-associated mitochondrial translation

    NARCIS (Netherlands)

    K. Rooijers (Koos); F. Loayza-Puch (Fabricio); L.G.J. Nijtmans (Leo); R. Agami (Reuven)

    2013-01-01

    textabstractMitochondria are essential cellular organelles for generation of energy and their dysfunction may cause diabetes, Parkinson's disease and multi-systemic failure marked by failure to thrive, gastrointestinal problems, lactic acidosis and early lethality. Disease-associated mitochondrial

  2. Gestational protein restriction induces alterations in placental morphology and mitochondrial function in rats during late pregnancy.

    Science.gov (United States)

    Rebelato, Hércules Jonas; Esquisatto, Marcelo Augusto Marreto; Moraes, Camila; Amaral, Maria Esmeria Corezola; Catisti, Rosana

    2013-12-01

    The placenta acts a regulator of nutrient composition and supply from mother to fetus and is the source of hormonal signals that affect maternal and fetal metabolism. Thus, appropriate development of the placenta is crucial for normal fetal development. We investigated the effect of gestational protein restriction (GPR) on placental morphology and mitochondrial function on day 19 of gestation. Pregnant dams were divided into two groups: normal (NP 17 % casein) or low-protein diet (LP 6 % casein). The placentas were processed for biochemical, histomorphometric and ultrastructural analysis. The integrity of rat placental mitochondria (RPM) isolated by conventional differential centrifugation was measured by oxygen uptake (Clark-type electrode). LP animals presented an increase in adipose tissue and triacylglycerol and a decrease in serum insulin levels. No alterations were observed in body, liver, fetus, or placenta weight. There was also no change in serum glucose, total protein, or lipid content. Gestational protein restriction had tissue-specific respiratory effects, with the observation of a small change in liver respiration (~13 %) and considerable respiratory inhibition in placenta samples (~37 %). The higher oxygen uptake by RPM in the LP groups suggests uncoupling between respiration and oxidative phosphorylation. In addition, ultrastructural analysis of junctional zone giant cells from LP placenta showed a disorganized cytoplasm, with loss of integrity of most organelles and intense vacuolization. The present results led us to hypothesize that GPR alters placental structure and morphology, induces sensitivity to insulin, mitochondrial abnormalities and suggests premature aging of the placenta. Further studies are needed to test this hypothesis.

  3. In vivo multiphoton imaging of mitochondrial structure and function during acute kidney injury.

    Science.gov (United States)

    Hall, Andrew M; Rhodes, George J; Sandoval, Ruben M; Corridon, Peter R; Molitoris, Bruce A

    2013-01-01

    Mitochondrial dysfunction has been implicated in the pathogenesis of acute kidney injury due to ischemia and toxic drugs. Methods for imaging mitochondrial function in cells using confocal microscopy are well established; more recently, it was shown that these techniques can be utilized in ex vivo kidney tissue using multiphoton microscopy. We extended this approach in vivo and found that kidney mitochondrial structure and function can be imaged in anesthetized rodents using multiphoton excitation of endogenous and exogenous fluorophores. Mitochondrial nicotinamide adenine dinucleotide increased markedly in rat kidneys in response to ischemia. Following intravenous injection, the mitochondrial membrane potential-dependent dye TMRM was taken up by proximal tubules; in response to ischemia, the membrane potential dissipated rapidly and mitochondria became shortened and fragmented in proximal tubules. In contrast, the mitochondrial membrane potential and structure were better maintained in distal tubules. Changes in mitochondrial structure, nicotinamide adenine dinucleotide, and membrane potential were found in the proximal, but not distal, tubules after gentamicin exposure. These changes were sporadic, highly variable among animals, and were preceded by changes in non-mitochondrial structures. Thus, real-time changes in mitochondrial structure and function can be imaged in rodent kidneys in vivo using multiphoton excitation of endogenous and exogenous fluorophores in response to ischemia-reperfusion injury or drug toxicity.

  4. Altered mitochondrial function and oxidative stress in leukocytes of anorexia nervosa patients.

    Science.gov (United States)

    Victor, Victor M; Rovira-Llopis, Susana; Saiz-Alarcon, Vanessa; Sangüesa, Maria C; Rojo-Bofill, Luis; Bañuls, Celia; Falcón, Rosa; Castelló, Raquel; Rojo, Luis; Rocha, Milagros; Hernández-Mijares, Antonio

    2014-01-01

    Anorexia nervosa is a common illness among adolescents and is characterised by oxidative stress. The effects of anorexia on mitochondrial function and redox state in leukocytes from anorexic subjects were evaluated. A multi-centre, cross-sectional case-control study was performed. Our study population consisted of 20 anorexic patients and 20 age-matched controls, all of which were Caucasian women. Anthropometric and metabolic parameters were evaluated in the study population. To assess whether anorexia nervosa affects mitochondrial function and redox state in leukocytes of anorexic patients, we measured mitochondrial oxygen consumption, membrane potential, reactive oxygen species production, glutathione levels, mitochondrial mass, and complex I and III activity in polymorphonuclear cells. Mitochondrial function was impaired in the leukocytes of the anorexic patients. This was evident in a decrease in mitochondrial O2 consumption (Panorexic patients (Panorexic patients and is closely related to mitochondrial dysfunction. Our results lead us to propose that the oxidative stress that occurs in anorexia takes place at mitochondrial complex I. Future research concerning mitochondrial dysfunction and oxidative stress should aim to determine the physiological mechanism involved in this effect and the physiological impact of anorexia.

  5. Mitochondrial function in human skeletal muscle following high-altitude exposure

    DEFF Research Database (Denmark)

    Jacobs, Robert A; Boushel, Robert; Wright-Paradis, Cynthia

    2013-01-01

    Studies regarding mitochondrial modifications in human skeletal muscle following acclimatization to high altitude are conflicting, and these inconsistencies may be due to the prevalence of representing mitochondrial function through static and isolated measurements of specific mitochondrial...... characteristics. The aim of this study, therefore, was to investigate mitochondrial function in response to high-altitude acclimatization through measurements of respiratory control in the vastus lateralis muscle. Skeletal muscle biopsies were obtained from 10 lowland natives prior to and again after a total of 9......-11 days of exposure to 4559 m. High-resolution respirometry was performed on the muscle samples to compare respiratory chain function and respiratory capacities. Respirometric analysis revealed that mitochondrial function was largely unaffected, because high-altitude exposure did not affect the capacity...

  6. Altered mitochondrial function and oxidative stress in leukocytes of anorexia nervosa patients.

    Directory of Open Access Journals (Sweden)

    Victor M Victor

    Full Text Available CONTEXT: Anorexia nervosa is a common illness among adolescents and is characterised by oxidative stress. OBJECTIVE: The effects of anorexia on mitochondrial function and redox state in leukocytes from anorexic subjects were evaluated. DESIGN AND SETTING: A multi-centre, cross-sectional case-control study was performed. PATIENTS: Our study population consisted of 20 anorexic patients and 20 age-matched controls, all of which were Caucasian women. MAIN OUTCOME MEASURES: Anthropometric and metabolic parameters were evaluated in the study population. To assess whether anorexia nervosa affects mitochondrial function and redox state in leukocytes of anorexic patients, we measured mitochondrial oxygen consumption, membrane potential, reactive oxygen species production, glutathione levels, mitochondrial mass, and complex I and III activity in polymorphonuclear cells. RESULTS: Mitochondrial function was impaired in the leukocytes of the anorexic patients. This was evident in a decrease in mitochondrial O2 consumption (P<0.05, mitochondrial membrane potential (P<0.01 and GSH levels (P<0.05, and an increase in ROS production (P<0.05 with respect to control subjects. Furthermore, a reduction of mitochondrial mass was detected in leukocytes of the anorexic patients (P<0.05, while the activity of mitochondrial complex I (P<0.001, but not that of complex III, was found to be inhibited in the same population. CONCLUSIONS: Oxidative stress is produced in the leukocytes of anorexic patients and is closely related to mitochondrial dysfunction. Our results lead us to propose that the oxidative stress that occurs in anorexia takes place at mitochondrial complex I. Future research concerning mitochondrial dysfunction and oxidative stress should aim to determine the physiological mechanism involved in this effect and the physiological impact of anorexia.

  7. Mitochondrial Dynamics in Mitochondrial Diseases

    Directory of Open Access Journals (Sweden)

    Juan M. Suárez-Rivero

    2016-12-01

    Full Text Available Mitochondria are very versatile organelles in continuous fusion and fission processes in response to various cellular signals. Mitochondrial dynamics, including mitochondrial fission/fusion, movements and turnover, are essential for the mitochondrial network quality control. Alterations in mitochondrial dynamics can cause neuropathies such as Charcot-Marie-Tooth disease in which mitochondrial fusion and transport are impaired, or dominant optic atrophy which is caused by a reduced mitochondrial fusion. On the other hand, mitochondrial dysfunction in primary mitochondrial diseases promotes reactive oxygen species production that impairs its own function and dynamics, causing a continuous vicious cycle that aggravates the pathological phenotype. Mitochondrial dynamics provides a new way to understand the pathophysiology of mitochondrial disorders and other diseases related to mitochondria dysfunction such as diabetes, heart failure, or Hungtinton’s disease. The knowledge about mitochondrial dynamics also offers new therapeutics targets in mitochondrial diseases.

  8. Mitochondrial functions modulate neuroendocrine, metabolic, inflammatory, and transcriptional responses to acute psychological stress

    Science.gov (United States)

    Picard, Martin; McManus, Meagan J.; Gray, Jason D.; Nasca, Carla; Moffat, Cynthia; Kopinski, Piotr K.; Seifert, Erin L.; McEwen, Bruce S.; Wallace, Douglas C.

    2015-01-01

    The experience of psychological stress triggers neuroendocrine, inflammatory, metabolic, and transcriptional perturbations that ultimately predispose to disease. However, the subcellular determinants of this integrated, multisystemic stress response have not been defined. Central to stress adaptation is cellular energetics, involving mitochondrial energy production and oxidative stress. We therefore hypothesized that abnormal mitochondrial functions would differentially modulate the organism’s multisystemic response to psychological stress. By mutating or deleting mitochondrial genes encoded in the mtDNA [NADH dehydrogenase 6 (ND6) and cytochrome c oxidase subunit I (COI)] or nuclear DNA [adenine nucleotide translocator 1 (ANT1) and nicotinamide nucleotide transhydrogenase (NNT)], we selectively impaired mitochondrial respiratory chain function, energy exchange, and mitochondrial redox balance in mice. The resulting impact on physiological reactivity and recovery from restraint stress were then characterized. We show that mitochondrial dysfunctions altered the hypothalamic–pituitary–adrenal axis, sympathetic adrenal–medullary activation and catecholamine levels, the inflammatory cytokine IL-6, circulating metabolites, and hippocampal gene expression responses to stress. Each mitochondrial defect generated a distinct whole-body stress-response signature. These results demonstrate the role of mitochondrial energetics and redox balance as modulators of key pathophysiological perturbations previously linked to disease. This work establishes mitochondria as stress-response modulators, with implications for understanding the mechanisms of stress pathophysiology and mitochondrial diseases. PMID:26627253

  9. Assessment of gastroprotective effect of crude tannin from Schwenkia americana Linn. on mitochondrial functions in ulcerogenic rats

    Directory of Open Access Journals (Sweden)

    George Edaghogho Eriyamremu

    2017-05-01

    Full Text Available Objective: To investigate the gastroprotective effect of tannin from Schwenkia americana Linn. on mitochondrial functions in ulcerogenic rats. Methods: A total number of 36 male Wistar rats weighing 160–220 g were used for the study. The rats were divided into six groups with six rats each group. Groups I and II were orally administered with distilled water, Groups III, IV and V with 50 mg/kg, 100 mg/kg and 200 mg/ kg of extracted tannin whilst Group VI administered with omeprazole, respectively for 7 days. All animals were fasted for 24 h before single administration of 800 mg/kg body weight of aspirin, except for Group I (normal control. Ulcerogenic activity and mitochondrial functional parameters were assessed. Results: Administration of aspirin significantly (P < 0.05 increased free and total acidity, quantity of gastric juice, protein, pepsin activity and decreased tricarboxylic acid cycle enzymes, ATPases, fucose, sialic, hexosamine, hexose and mucin level in ulcerated rats (Group II. There was also dissipation of mitochondrial membrane potential in ulcerated rats, but prior pretreatment of extracted tannin and omeprazole prevented theses biochemical effects. Conclusions: Tannin from Schwenkia americana prevented impaired stomach mitochondrial functions in aspirin induced gastric damage and may also act as gastroprotective of the gastric mucosal.

  10. Normalized impedance function and the straightforward inversion ...

    Indian Academy of Sciences (India)

    inverted through SIS for comparison. We noticed that the new function and SIS compliment each other and ... The process of inverting the MT data sets, usually of inadequate quality and quantity, is beset by the endemic ..... ter α controls the depth to which a conductive hori- zon can be detected as demonstrated for the Cull.

  11. Normalized impedance function and the straightforward inversion ...

    Indian Academy of Sciences (India)

    The linear straightforward inversion scheme (SIS),developed by the authors employing the concept of equal penetration layers,has been used to validate the proposed apparent resistivity functions.For this purpose,several ... Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee, UA 247 667, India.

  12. Metformin-treated patients with type 2 diabetes have normal mitochondrial complex I respiration.

    Science.gov (United States)

    Larsen, S; Rabøl, R; Hansen, C N; Madsbad, S; Helge, J W; Dela, F

    2012-02-01

    The glucose-lowering drug metformin has been shown to inhibit complex I of the mitochondrial electron transport chain in skeletal muscle. To investigate this effect in vivo we studied skeletal muscle mitochondrial respiratory capacity and content from patients with type 2 diabetes treated with metformin (n = 14) or sulfonylurea (n = 8) and healthy control (n = 18) participants. Mitochondrial respiratory capacity was measured ex vivo in permeabilised muscle fibres obtained from the vastus lateralis muscle of all participants. The respiratory response to in vitro titration with metformin was measured in controls. Citrate synthase (CS) activity, and fasting plasma glucose, insulin and HbA(1c) levels were measured and body composition was determined. Participants were matched for age, BMI and percentage body fat. Fasting plasma glucose concentrations were higher (p muscle at suprapharmacological concentrations. Metformin treatment does not inhibit mitochondrial complex I respiration in the electron transport chain in human skeletal muscle of patients with type 2 diabetes when measured ex vivo. Inhibition of complex I and II respiration in controls was demonstrated by metformin titration in vitro at doses well above those observed during metformin treatment.

  13. Hepatic mitochondrial oxidative phosphorylation is normal in obese patients with and without type 2 diabetes

    DEFF Research Database (Denmark)

    Lund, Michael Taulo; Kristensen, Marianne Dalsgaard; Hansen, Merethe

    2016-01-01

    INTRODUCTION: Obese patients with (T2DM) and without (OB) type 2 diabetes are characterized by high hepatic lipid content and hepatic insulin resistance. This may be linked to impaired hepatic mitochondrial oxidative phosphorylation (OXPHOS) capacity. The aim of the present study was to investiga...

  14. The relationship between mitochondrial DNA copy number and stallion sperm function.

    Science.gov (United States)

    Darr, Christa R; Moraes, Luis E; Connon, Richard E; Love, Charles C; Teague, Sheila; Varner, Dickson D; Meyers, Stuart A

    2017-05-01

    Mitochondrial DNA (mtDNA) copy number has been utilized as a measure of sperm quality in several species including mice, dogs, and humans, and has been suggested as a potential biomarker of fertility in stallion sperm. The results of the present study extend this recent discovery using sperm samples from American Quarter Horse stallions of varying age. By determining copy number of three mitochondrial genes, cytochrome b (CYTB), NADH dehydrogenase 1 (ND1) and NADH dehydrogenase 4 (ND4), instead of a single gene, we demonstrate an improved understanding of mtDNA fate in stallion sperm mitochondria following spermatogenesis. Sperm samples from 37 stallions ranging from 3 to 24 years old were collected at four breeding ranches in north and central Texas during the 2015 breeding season. Samples were analyzed for sperm motion characteristics, nuclear DNA denaturability and mtDNA copy number. Mitochondrial DNA content in individual sperm was determined by real-time qPCR and normalized with a single copy nuclear gene, Beta actin. Exploratory correlation analysis revealed that total motility was negatively correlated with CYTB copy number and sperm chromatin structure. Stallion age did not have a significant effect on copy number for any of the genes. Copy number differences existed between the three genes with CYTB having the greatest number of copies (20.6 ± 1.2 copies, range: 6.0 to 41.1) followed by ND4 (15.5 ± 0.8 copies, range: 6.7 to 27.8) and finally ND1 (12.0 ± 1.0 copies, range: 0.4 to 26.6) (P sperm mtDNA occurs during spermatogenesis and may be important for normal sperm function. Beta regression analysis suggested that for every unit increase in mtDNA copy number of CYTB, there was a 4% decrease in the odds of sperm movement (P = 0.001). Influential analysis suggested that results are robust and not highly influenced by data from individual stallions despite the low number of stallions sampled with low sperm motility. Further genome sequencing is

  15. Mitochondrial protein import machineries and lipids: a functional connection.

    Science.gov (United States)

    Gebert, Natalia; Ryan, Michael T; Pfanner, Nikolaus; Wiedemann, Nils; Stojanovski, Diana

    2011-03-01

    Protein trafficking and translocation are essential processes in even the simplest living cells. The compartmentalisation within eukaryotic cells places a very high demand on the fidelity of protein trafficking and translocation, since a large percentage of the cell's protein complement is inserted into, or translocated across membranes. Indeed, most mitochondrial proteins are imported from the cytosol into the organelle and reach their final destination with the assistance of versatile translocation machineries. The first components involved in mitochondrial protein import were identified about 20years ago and over the last two decades many new factors and machineries have been brought to light. However, in spite of these discoveries we still have much to explore regarding the molecular mechanisms that distinguish the different mitochondrial import pathways. In particular, an open question that requires deeper exploration is the role of lipids and lipid modifying enzymes in this process. Mitochondrial biogenesis requires the coordinated synthesis and import of both proteins and phospholipids, however, these have typically been considered as distinct research fields. Recent findings have placed phospholipids at the forefront of research dealing with mitochondrial biogenesis, in particular their role in the regulation of mitochondrial transport machineries. This article is part of a Special Issue entitled Protein translocation across or insertion into membranes. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. Disruption of mitochondrial electron transport chain function potentiates the pro-apoptotic effects of MAPK inhibition.

    Science.gov (United States)

    Trotta, Andrew P; Gelles, Jesse D; Serasinghe, Madhavika N; Loi, Patrick; Arbiser, Jack L; Chipuk, Jerry E

    2017-07-14

    The mitochondrial network is a major site of ATP production through the coupled integration of the electron transport chain (ETC) with oxidative phosphorylation. In melanoma arising from the V600E mutation in the kinase v-RAF murine sarcoma viral oncogene homolog B (BRAF V600E ), oncogenic signaling enhances glucose-dependent metabolism while reducing mitochondrial ATP production. Likewise, when BRAF V600E is pharmacologically inhibited by targeted therapies ( e.g. PLX-4032/vemurafenib), glucose metabolism is reduced, and cells increase mitochondrial ATP production to sustain survival. Therefore, collateral inhibition of oncogenic signaling and mitochondrial respiration may help enhance the therapeutic benefit of targeted therapies. Honokiol (HKL) is a well tolerated small molecule that disrupts mitochondrial function; however, its underlying mechanisms and potential utility with targeted anticancer therapies remain unknown. Using wild-type BRAF and BRAF V600E melanoma model systems, we demonstrate here that HKL administration rapidly reduces mitochondrial respiration by broadly inhibiting ETC complexes I, II, and V, resulting in decreased ATP levels. The subsequent energetic crisis induced two cellular responses involving cyclin-dependent kinases (CDKs). First, loss of CDK1-mediated phosphorylation of the mitochondrial division GTPase dynamin-related protein 1 promoted mitochondrial fusion, thus coupling mitochondrial energetic status and morphology. Second, HKL decreased CDK2 activity, leading to G 1 cell cycle arrest. Importantly, although pharmacological inhibition of oncogenic MAPK signaling increased ETC activity, co-treatment with HKL ablated this response and vastly enhanced the rate of apoptosis. Collectively, these findings integrate HKL action with mitochondrial respiration and shape and substantiate a pro-survival role of mitochondrial function in melanoma cells after oncogenic MAPK inhibition.

  17. Mitochondrial DNA damage and vascular function in patients with diabetes mellitus and atherosclerotic cardiovascular disease.

    Science.gov (United States)

    Fetterman, Jessica L; Holbrook, Monica; Westbrook, David G; Brown, Jamelle A; Feeley, Kyle P; Bretón-Romero, Rosa; Linder, Erika A; Berk, Brittany D; Weisbrod, Robert M; Widlansky, Michael E; Gokce, Noyan; Ballinger, Scott W; Hamburg, Naomi M

    2016-03-31

    Prior studies demonstrate mitochondrial dysfunction with increased reactive oxygen species generation in peripheral blood mononuclear cells in diabetes mellitus. Oxidative stress-mediated damage to mitochondrial DNA promotes atherosclerosis in animal models. Thus, we evaluated the relation of mitochondrial DNA damage in peripheral blood mononuclear cells s with vascular function in patients with diabetes mellitus and with atherosclerotic cardiovascular disease. We assessed non-invasive vascular function and mitochondrial DNA damage in 275 patients (age 57 ± 9 years, 60 % women) with atherosclerotic cardiovascular disease alone (N = 55), diabetes mellitus alone (N = 74), combined atherosclerotic cardiovascular disease and diabetes mellitus (N = 48), and controls age >45 without diabetes mellitus or atherosclerotic cardiovascular disease (N = 98). Mitochondrial DNA damage measured by quantitative PCR in peripheral blood mononuclear cells was higher with clinical atherosclerosis alone (0.55 ± 0.65), diabetes mellitus alone (0.65 ± 1.0), and combined clinical atherosclerosis and diabetes mellitus (0.89 ± 1.32) as compared to control subjects (0.23 ± 0.64, P mitochondrial DNA damage levels (β = 0.14 ± 0.13, P = 0.04 and β = 0.21 ± 0.13, P = 0.002, respectively). Higher mitochondrial DNA damage was associated with higher baseline pulse amplitude, a measure of arterial pulsatility, but not with flow-mediated dilation or hyperemic response, measures of vasodilator function. We found greater mitochondrial DNA damage in patients with diabetes mellitus and clinical atherosclerosis. The association of mitochondrial DNA damage and baseline pulse amplitude may suggest a link between mitochondrial dysfunction and excessive small artery pulsatility with potentially adverse microvascular impact.

  18. Impact of Resistance Training on Skeletal Muscle Mitochondrial Biogenesis, Content, and Function

    Directory of Open Access Journals (Sweden)

    Thomas Groennebaek

    2017-09-01

    Full Text Available Skeletal muscle metabolic and contractile properties are reliant on muscle mitochondrial and myofibrillar protein turnover. The turnover of these specific protein pools is compromised during disease, aging, and inactivity. Oppositely, exercise can accentuate muscle protein turnover, thereby counteracting decay in muscle function. According to a traditional consensus, endurance exercise is required to drive mitochondrial adaptations, while resistance exercise is required to drive myofibrillar adaptations. However, concurrent practice of traditional endurance exercise and resistance exercise regimens to achieve both types of muscle adaptations is time-consuming, motivationally demanding, and contended to entail practice at intensity levels, that may not comply with clinical settings. It is therefore of principle interest to identify effective, yet feasible, exercise strategies that may positively affect both mitochondrial and myofibrillar protein turnover. Recently, reports indicate that traditional high-load resistance exercise can stimulate muscle mitochondrial biogenesis and mitochondrial respiratory function. Moreover, fatiguing low-load resistance exercise has been shown capable of promoting muscle hypertrophy and expectedly entails greater metabolic stress to potentially enhance mitochondrial adaptations. Consequently, fatiguing low-load resistance exercise regimens may possess the ability to stimulate muscle mitochondrial adaptations without compromising muscle myofibrillar accretion. However, the exact ability of resistance exercise to drive mitochondrial adaptations is debatable, not least due to some methodological challenges. The current review therefore aims to address the evidence on the effects of resistance exercise on skeletal muscle mitochondrial biogenesis, content and function. In prolongation, a perspective is taken on the specific potential of low-load resistance exercise on promoting mitochondrial adaptations.

  19. Selective propagation of functional mitochondrial DNA during oogenesis restricts the transmission of a deleterious mitochondrial variant.

    Science.gov (United States)

    Hill, Jahda H; Chen, Zhe; Xu, Hong

    2014-04-01

    Although mitochondrial DNA (mtDNA) is prone to mutation and few mtDNA repair mechanisms exist, crippling mitochondrial mutations are exceedingly rare. Recent studies have demonstrated strong purifying selection in the mouse female germline. However, the mechanisms underlying positive selection of healthy mitochondria remain to be elucidated. We visualized mtDNA replication during Drosophila melanogaster oogenesis, finding that mtDNA replication commenced before oocyte determination during the late germarium stage and was dependent on mitochondrial fitness. We isolated a temperature-sensitive lethal mtDNA allele, mt:CoI(T300I), which resulted in reduced mtDNA replication in the germarium at the restrictive temperature. Additionally, the frequency of the mt:CoI(T300I) allele in heteroplasmic flies was decreased, both during oogenesis and over multiple generations, at the restrictive temperature. Furthermore, we determined that selection against mt:CoI(T300I) overlaps with the timing of selective replication of mtDNA in the germarium. These findings establish a previously uncharacterized developmental mechanism for the selective amplification of wild-type mtDNA, which may be evolutionarily conserved to limit the transmission of deleterious mutations.

  20. Mitochondrial metabolism in hematopoietic stem cells requires functional FOXO3

    Science.gov (United States)

    Rimmelé, Pauline; Liang, Raymond; Bigarella, Carolina L; Kocabas, Fatih; Xie, Jingjing; Serasinghe, Madhavika N; Chipuk, Jerry; Sadek, Hesham; Zhang, Cheng Cheng; Ghaffari, Saghi

    2015-01-01

    Hematopoietic stem cells (HSC) are primarily dormant but have the potential to become highly active on demand to reconstitute blood. This requires a swift metabolic switch from glycolysis to mitochondrial oxidative phosphorylation. Maintenance of low levels of reactive oxygen species (ROS), a by-product of mitochondrial metabolism, is also necessary for sustaining HSC dormancy. Little is known about mechanisms that integrate energy metabolism with hematopoietic stem cell homeostasis. Here, we identify the transcription factor FOXO3 as a new regulator of metabolic adaptation of HSC. ROS are elevated in Foxo3−/− HSC that are defective in their activity. We show that Foxo3−/− HSC are impaired in mitochondrial metabolism independent of ROS levels. These defects are associated with altered expression of mitochondrial/metabolic genes in Foxo3−/− hematopoietic stem and progenitor cells (HSPC). We further show that defects of Foxo3−/− HSC long-term repopulation activity are independent of ROS or mTOR signaling. Our results point to FOXO3 as a potential node that couples mitochondrial metabolism with HSC homeostasis. These findings have critical implications for mechanisms that promote malignant transformation and aging of blood stem and progenitor cells. PMID:26209246

  1. Is Placental Mitochondrial Function a Regulator that Matches Fetal and Placental Growth to Maternal Nutrient Intake in the Mouse?

    Science.gov (United States)

    Chiaratti, Marcos R; Malik, Sajida; Diot, Alan; Rapa, Elizabeth; Macleod, Lorna; Morten, Karl; Vatish, Manu; Boyd, Richard; Poulton, Joanna

    2015-01-01

    Effective fetal growth requires adequate maternal nutrition coupled to active transport of nutrients across the placenta, which, in turn requires ATP. Epidemiological and experimental evidence has shown that impaired maternal nutrition in utero results in an adverse postnatal phenotype for the offspring. Placental mitochondrial function might link maternal food intake to fetal growth since impaired placental ATP production, in response to poor maternal nutrition, could be a pathway linking maternal food intake to reduced fetal growth. We assessed the effects of maternal diet on placental water content, ATP levels and mitochondrial DNA (mtDNA) content in mice at embryonic (E) day 18 (E18). Females maintained on either low- (LPD) or normal- (NPD) protein diets were mated with NPD males. Fetal dry weight and placental efficiency (embryo/placental fresh weight) were positively correlated (r = 0.53, P = 0.0001). Individual placental dry weight was reduced by LPD (P = 0.003), as was the expression of amino acid transporter Slc38a2 and of growth factor Igf2. Placental water content, which is regulated by active transport of solutes, was increased by LPD (P = 0.0001). However, placental ATP content was also increased (P = 0.03). To investigate the possibility of an underlying mitochondrial stress response, we studied cultured human trophoblast cells (BeWos). High throughput imaging showed that amino acid starvation induces changes in mitochondrial morphology that suggest stress-induced mitochondrial hyperfusion. This is a defensive response, believed to increase mitochondrial efficiency, that could underlie the increase in ATP observed in placenta. These findings reinforce the pathophysiological links between maternal diet and conceptus mitochondria, potentially contributing to metabolic programming. The quiet embryo hypothesis proposes that pre-implantation embryo survival is best served by a relatively low level of metabolism. This may extend to post

  2. Is Placental Mitochondrial Function a Regulator that Matches Fetal and Placental Growth to Maternal Nutrient Intake in the Mouse?

    Directory of Open Access Journals (Sweden)

    Marcos R Chiaratti

    Full Text Available Effective fetal growth requires adequate maternal nutrition coupled to active transport of nutrients across the placenta, which, in turn requires ATP. Epidemiological and experimental evidence has shown that impaired maternal nutrition in utero results in an adverse postnatal phenotype for the offspring. Placental mitochondrial function might link maternal food intake to fetal growth since impaired placental ATP production, in response to poor maternal nutrition, could be a pathway linking maternal food intake to reduced fetal growth.We assessed the effects of maternal diet on placental water content, ATP levels and mitochondrial DNA (mtDNA content in mice at embryonic (E day 18 (E18. Females maintained on either low- (LPD or normal- (NPD protein diets were mated with NPD males.Fetal dry weight and placental efficiency (embryo/placental fresh weight were positively correlated (r = 0.53, P = 0.0001. Individual placental dry weight was reduced by LPD (P = 0.003, as was the expression of amino acid transporter Slc38a2 and of growth factor Igf2. Placental water content, which is regulated by active transport of solutes, was increased by LPD (P = 0.0001. However, placental ATP content was also increased (P = 0.03. To investigate the possibility of an underlying mitochondrial stress response, we studied cultured human trophoblast cells (BeWos. High throughput imaging showed that amino acid starvation induces changes in mitochondrial morphology that suggest stress-induced mitochondrial hyperfusion. This is a defensive response, believed to increase mitochondrial efficiency, that could underlie the increase in ATP observed in placenta.These findings reinforce the pathophysiological links between maternal diet and conceptus mitochondria, potentially contributing to metabolic programming. The quiet embryo hypothesis proposes that pre-implantation embryo survival is best served by a relatively low level of metabolism. This may extend to post

  3. Metformin improves cardiac function in mice with heart failure after myocardial infarction by regulating mitochondrial energy metabolism.

    Science.gov (United States)

    Sun, Dan; Yang, Fei

    2017-04-29

    To investigate whether metformin can improve the cardiac function through improving the mitochondrial function in model of heart failure after myocardial infarction. Male C57/BL6 mice aged about 8 weeks were selected and the anterior descending branch was ligatured to establish the heart failure model after myocardial infarction. The cardiac function was evaluated via ultrasound after 3 days to determine the modeling was successful, and the mice were randomly divided into two groups. Saline group (Saline) received the intragastric administration of normal saline for 4 weeks, and metformin group (Met) received the intragastric administration of metformin for 4 weeks. At the same time, Shame group (Sham) was set up. Changes in cardiac function in mice were detected at 4 weeks after operation. Hearts were taken from mice after 4 weeks, and cell apoptosis in myocardial tissue was detected using TUNEL method; fresh mitochondria were taken and changes in oxygen consumption rate (OCR) and respiratory control rate (RCR) of mitochondria in each group were detected using bio-energy metabolism tester, and change in mitochondrial membrane potential (MMP) of myocardial tissue was detected via JC-1 staining; the expressions and changes in Bcl-2, Bax, Sirt3, PGC-1α and acetylated PGC-1α in myocardial tissue were detected by Western blot. RT-PCR was used to detect mRNA levels in Sirt3 in myocardial tissues. Metformin improved the systolic function of heart failure model rats after myocardial infarction and reduced the apoptosis of myocardial cells after myocardial infarction. Myocardial mitochondrial respiratory function and membrane potential were decreased after myocardial infarction, and metformin treatment significantly improved the mitochondrial respiratory function and mitochondrial membrane potential; Metformin up-regulated the expression of Sirt3 and the activity of PGC-1α in myocardial tissue of heart failure after myocardial infarction. Metformin decreases the

  4. Enhanced Heme Function and Mitochondrial Respiration Promote the Progression of Lung Cancer Cells

    Science.gov (United States)

    Alam, Md Maksudul; Shah, Ajit; Cao, Thai M.; Sullivan, Laura A.; Brekken, Rolf; Zhang, Li

    2013-01-01

    Lung cancer is the leading cause of cancer-related mortality, and about 85% of the cases are non-small-cell lung cancer (NSCLC). Importantly, recent advance in cancer research suggests that altering cancer cell bioenergetics can provide an effective way to target such advanced cancer cells that have acquired mutations in multiple cellular regulators. This study aims to identify bioenergetic alterations in lung cancer cells by directly measuring and comparing key metabolic activities in a pair of cell lines representing normal and NSCLC cells developed from the same patient. We found that the rates of oxygen consumption and heme biosynthesis were intensified in NSCLC cells. Additionally, the NSCLC cells exhibited substantially increased levels in an array of proteins promoting heme synthesis, uptake and function. These proteins include the rate-limiting heme biosynthetic enzyme ALAS, transporter proteins HRG1 and HCP1 that are involved in heme uptake, and various types of oxygen-utilizing hemoproteins such as cytoglobin and cytochromes. Several types of human tumor xenografts also displayed increased levels of such proteins. Furthermore, we found that lowering heme biosynthesis and uptake, like lowering mitochondrial respiration, effectively reduced oxygen consumption, cancer cell proliferation, migration and colony formation. In contrast, lowering heme degradation does not have an effect on lung cancer cells. These results show that increased heme flux and function are a key feature of NSCLC cells. Further, increased generation and supply of heme and oxygen-utilizing hemoproteins in cancer cells will lead to intensified oxygen consumption and cellular energy production by mitochondrial respiration, which would fuel cancer cell proliferation and progression. The results show that inhibiting heme and respiratory function can effectively arrest the progression of lung cancer cells. Hence, understanding heme function can positively impact on research in lung cancer

  5. Oxidative stress modulates mitochondrial failure and cyclophilin D function in X-linked adrenoleukodystrophy.

    Science.gov (United States)

    López-Erauskin, Jone; Galino, Jorge; Bianchi, Patrizia; Fourcade, Stéphane; Andreu, Antoni L; Ferrer, Isidre; Muñoz-Pinedo, Cristina; Pujol, Aurora

    2012-12-01

    A common process associated with oxidative stress and severe mitochondrial impairment is the opening of the mitochondrial permeability transition pore, as described in many neurodegenerative diseases. Thus, inhibition of mitochondrial permeability transition pore opening represents a potential target for inhibiting mitochondrial-driven cell death. Among the mitochondrial permeability transition pore components, cyclophilin D is the most studied and has been found increased under pathological conditions. Here, we have used in vitro and in vivo models of X-linked adrenoleukodystrophy to investigate the relationship between the mitochondrial permeability transition pore opening and redox homeostasis. X-linked adrenoleukodystrophy is a neurodegenerative condition caused by loss of function of the peroxisomal ABCD1 transporter, in which oxidative stress plays a pivotal role. In this study, we provide evidence of impaired mitochondrial metabolism in a peroxisomal disease, as fibroblasts in patients with X-linked adrenoleukodystrophy cannot survive when forced to rely on mitochondrial energy production, i.e. on incubation in galactose. Oxidative stress induced under galactose conditions leads to mitochondrial damage in the form of mitochondrial inner membrane potential dissipation, ATP drop and necrotic cell death, together with increased levels of oxidative modifications in cyclophilin D protein. Moreover, we show increased expression levels of cyclophilin D in the affected zones of brains in patients with adrenomyeloneuropathy, in spinal cord of a mouse model of X-linked adrenoleukodystrophy (Abcd1-null mice) and in fibroblasts from patients with X-linked adrenoleukodystrophy. Notably, treatment with antioxidants rescues mitochondrial damage markers in fibroblasts from patients with X-linked adrenoleukodystrophy, including cyclophilin D oxidative modifications, and reverses cyclophilin D induction in vitro and in vivo. These findings provide mechanistic insight into the

  6. Anilinopyrimidine Resistance in Botrytis cinerea Is Linked to Mitochondrial Function.

    Science.gov (United States)

    Mosbach, Andreas; Edel, Dominique; Farmer, Andrew D; Widdison, Stephanie; Barchietto, Thierry; Dietrich, Robert A; Corran, Andy; Scalliet, Gabriel

    2017-01-01

    Crop protection anilinopyrimidine (AP) fungicides were introduced more than 20 years ago for the control of a range of diseases caused by ascomycete plant pathogens, and in particular for the control of gray mold caused by Botrytis cinerea . Although early mode of action studies suggested an inhibition of methionine biosynthesis, the molecular target of this class of fungicides was never fully clarified. Despite AP-specific resistance having been described in B . cinerea field isolates and in multiple other targeted species, the underlying resistance mechanisms were unknown. It was therefore expected that the genetic characterization of resistance mechanisms would permit the identification of the molecular target of these fungicides. In order to explore the widest range of possible resistance mechanisms, AP-resistant B . cinerea UV laboratory mutants were generated and the mutations conferring resistance were determined by combining whole-genome sequencing and reverse genetics. Genetic mapping from a cross between a resistant field isolate and a sensitive reference isolate was used in parallel and led to the identification of an additional molecular determinant not found from the characterized UV mutant collection. Together, these two approaches enabled the characterization of an unrivaled diversity of resistance mechanisms. In total, we report the elucidation of resistance-conferring mutations within nine individual genes, two of which are responsible for almost all instances of AP resistance in the field. All identified resistance-conferring genes encode proteins that are involved in mitochondrial processes, suggesting that APs primarily target the mitochondria. The functions of these genes and their possible interactions are discussed in the context of the potential mode of action for this important class of fungicides.

  7. Anilinopyrimidine Resistance in Botrytis cinerea Is Linked to Mitochondrial Function

    Directory of Open Access Journals (Sweden)

    Andreas Mosbach

    2017-11-01

    Full Text Available Crop protection anilinopyrimidine (AP fungicides were introduced more than 20 years ago for the control of a range of diseases caused by ascomycete plant pathogens, and in particular for the control of gray mold caused by Botrytis cinerea. Although early mode of action studies suggested an inhibition of methionine biosynthesis, the molecular target of this class of fungicides was never fully clarified. Despite AP-specific resistance having been described in B. cinerea field isolates and in multiple other targeted species, the underlying resistance mechanisms were unknown. It was therefore expected that the genetic characterization of resistance mechanisms would permit the identification of the molecular target of these fungicides. In order to explore the widest range of possible resistance mechanisms, AP-resistant B. cinerea UV laboratory mutants were generated and the mutations conferring resistance were determined by combining whole-genome sequencing and reverse genetics. Genetic mapping from a cross between a resistant field isolate and a sensitive reference isolate was used in parallel and led to the identification of an additional molecular determinant not found from the characterized UV mutant collection. Together, these two approaches enabled the characterization of an unrivaled diversity of resistance mechanisms. In total, we report the elucidation of resistance-conferring mutations within nine individual genes, two of which are responsible for almost all instances of AP resistance in the field. All identified resistance-conferring genes encode proteins that are involved in mitochondrial processes, suggesting that APs primarily target the mitochondria. The functions of these genes and their possible interactions are discussed in the context of the potential mode of action for this important class of fungicides.

  8. Impaired mitochondrial function in chronically ischemic human heart

    DEFF Research Database (Denmark)

    Stride, Nis Ottesen; Larsen, Steen; Hey-Mogensen, Martin

    2013-01-01

    Chronic ischemic heart disease is associated with myocardial hypoperfusion. The resulting hypoxia potentially inflicts damage upon the mitochondria, leading to a compromised energetic state. Furthermore, ischemic damage may cause excessive production of reactive oxygen species (ROS), producing...... mitochondrial damage, hereby reinforcing a vicious circle. Ischemic preconditioning has been proven protective in acute ischemia, but the subject of chronic ischemic preconditioning has not been explored in humans. We hypothesized that mitochondrial respiratory capacity would be diminished in chronic ischemic...... regions of human myocardium but that these mitochondria would be more resistant to ex vivo ischemia and, second, that ROS generation would be higher in ischemic myocardium. The aim of this study was to test mitochondrial respiratory capacity during hyperoxia and hypoxia, to investigate ROS production...

  9. Bitter taste receptor agonists alter mitochondrial function and induce autophagy in airway smooth muscle cells.

    Science.gov (United States)

    Pan, Shi; Sharma, Pawan; Shah, Sushrut D; Deshpande, Deepak A

    2017-07-01

    Airway remodeling, including increased airway smooth muscle (ASM) mass, is a hallmark feature of asthma and COPD. We previously identified the expression of bitter taste receptors (TAS2Rs) on human ASM cells and demonstrated that known TAS2R agonists could promote ASM relaxation and bronchodilation and inhibit mitogen-induced ASM growth. In this study, we explored cellular mechanisms mediating the antimitogenic effect of TAS2R agonists on human ASM cells. Pretreatment of ASM cells with TAS2R agonists chloroquine and quinine resulted in inhibition of cell survival, which was largely reversed by bafilomycin A1, an autophagy inhibitor. Transmission electron microscope studies demonstrated the presence of double-membrane autophagosomes and deformed mitochondria. In ASM cells, TAS2R agonists decreased mitochondrial membrane potential and increased mitochondrial ROS and mitochondrial fragmentation. Inhibiting dynamin-like protein 1 (DLP1) reversed TAS2R agonist-induced mitochondrial membrane potential change and attenuated mitochondrial fragmentation and cell death. Furthermore, the expression of mitochondrial protein BCL2/adenovirus E1B 19-kDa protein-interacting protein 3 (Bnip3) and mitochondrial localization of DLP1 were significantly upregulated by TAS2R agonists. More importantly, inhibiting Bnip3 mitochondrial localization by dominant-negative Bnip3 significantly attenuated cell death induced by TAS2R agonist. Collectively the TAS2R agonists chloroquine and quinine modulate mitochondrial structure and function, resulting in ASM cell death. Furthermore, Bnip3 plays a central role in TAS2R agonist-induced ASM functional changes via a mitochondrial pathway. These findings further establish the cellular mechanisms of antimitogenic effects of TAS2R agonists and identify a novel class of receptors and pathways that can be targeted to mitigate airway remodeling as well as bronchoconstriction in obstructive airway diseases. Copyright © 2017 the American Physiological

  10. Mitochondrial function is altered in horse atypical myopathy.

    Science.gov (United States)

    Lemieux, Hélène; Boemer, François; van Galen, Gaby; Serteyn, Didier; Amory, Hélène; Baise, Etienne; Cassart, Dominique; van Loon, Gunther; Marcillaud-Pitel, Christel; Votion, Dominique-M

    2016-09-01

    Equine atypical myopathy in Europe is a fatal rhabdomyolysis syndrome that results from the ingestion of hypoglycin A contained in seeds and seedlings of Acer pseudoplatanus (sycamore maple). Acylcarnitine concentrations in serum and muscle OXPHOS capacity were determined in 15 atypical myopathy cases. All but one acylcarnitine were out of reference range and mitochondrial respiratory capacity was severely decreased up to 49% as compared to 10 healthy controls. The hallmark of atypical myopathy thus consists of a severe alteration in the energy metabolism including a severe impairment in muscle mitochondrial respiration that could contribute to its high death rate. Copyright © 2016 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

  11. Cultured senescent myoblasts derived from human vastus lateralis exhibit normal mitochondrial ATP synthesis capacities with correlating concomitant ROS production while whole cell ATP production is decreased

    DEFF Research Database (Denmark)

    Minet, Ariane D; Gaster, Michael

    2012-01-01

    The free radical theory of aging says that increased oxidative stress and mitochondrial dysfunction are associated with old age. In the present study we have investigated the effects of cellular senescence on muscle energetic by comparing mitochondrial content and function in cultured muscle...... in the single mitochondrion in response to decreased mitochondrial mass and reduced extra-mitochondrial energy supply. This then can lead to the increased damage of DNA, lipids and proteins of the mitochondria as postulated by the free radical theory of aging....

  12. Effects of aging on mitochondrial function in skeletal muscle of American Quarter Horses

    Science.gov (United States)

    Li, Chengcheng; White, Sarah H.; Warren, Lori K.

    2016-01-01

    Skeletal muscle function, aerobic capacity, and mitochondrial (Mt) function have been found to decline with age in humans and rodents. However, not much is known about age-related changes in Mt function in equine skeletal muscle. Here, we compared fiber-type composition and Mt function in gluteus medius and triceps brachii muscle between young (age 1.8 ± 0.1 yr, n = 24) and aged (age 17-25 yr, n = 10) American Quarter Horses. The percentage of myosin heavy chain (MHC) IIX was lower in aged compared with young muscles (gluteus, P = 0.092; triceps, P = 0.012), while the percentages of MHC I (gluteus; P gluteus, but decreased in aged triceps (P = 0.023). Cytochrome-c oxidase (COX) activity per milligram tissue and per Mt unit decreased with age in gluteus (P gluteus and triceps (P = 0.023 and P < 0.001, respectively). Mt respiration of permeabilized muscle fibers per milligram tissue was unaffected by age in both muscles. Main effects of age appeared when respiration was normalized to Mt content, with increases in LEAK, oxidative phosphorylation capacity, and electron transport system capacity (P = 0.038, P = 0.045, and P = 0.007, respectively), independent of muscle. In conclusion, equine skeletal muscle aging was accompanied by a shift in fiber-type composition, decrease in Mt density and COX activity, but preserved Mt respiratory function. PMID:27283918

  13. Functional interplay between mitochondrial and proteasome activity in skin aging

    NARCIS (Netherlands)

    Kozie, Rafa; Greussing, Ruth; Maier, Andrea B.; Declercq, Lieve; Jansen-Dürr, Pidder

    According to the mitochondrial theory of aging, reactive oxygen species (ROS) derived primarily from mitochondria cause cumulative oxidative damage to various cellular molecules and thereby contribute to the aging process. On the other hand, a pivotal role of the proteasome, as a main proteolytic

  14. Effects of metformin on learning and memory behaviors and brain mitochondrial functions in high fat diet induced insulin resistant rats.

    Science.gov (United States)

    Pintana, Hiranya; Apaijai, Nattayaporn; Pratchayasakul, Wasana; Chattipakorn, Nipon; Chattipakorn, Siriporn C

    2012-10-05

    Metformin is a first line drug for the treatment of type 2 diabetes mellitus (T2DM). Our previous study reported that high-fat diet (HFD) consumption caused not only peripheral and neuronal insulin resistance, but also induced brain mitochondrial dysfunction as well as learning impairment. However, the effects of metformin on learning behavior and brain mitochondrial functions in HFD-induced insulin resistant rats have never been investigated. Thirty-two male Wistar rats were divided into two groups to receive either a normal diet (ND) or a high-fat diet (HFD) for 12weeks. Then, rats in each group were divided into two treatment groups to receive either vehicle or metformin (15mg/kg BW twice daily) for 21days. All rats were tested for cognitive behaviors using the Morris water maze (MWM) test, and blood samples were collected for the determination of glucose, insulin, and malondialdehyde. At the end of the study, animals were euthanized and the brain was removed for studying brain mitochondrial function and brain oxidative stress. We found that in the HFD group, metformin significantly attenuated the insulin resistant condition by improving metabolic parameters, decreasing peripheral and brain oxidative stress levels, and improving learning behavior, compared to the vehicle-treated group. Furthermore, metformin completely prevented brain mitochondrial dysfunction caused by long-term HFD consumption. Our findings suggest that metformin effectively improves peripheral insulin sensitivity, prevents brain mitochondrial dysfunction, and completely restores learning behavior, which were all impaired by long-term HFD consumption. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Relationship between PPARα mRNA expression and mitochondrial respiratory function and ultrastructure of the skeletal muscle of patients with COPD.

    Science.gov (United States)

    Zhang, Jian-Qing; Long, Xiang-Yu; Xie, Yu; Zhao, Zhi-Huan; Fang, Li-Zhou; Liu, Ling; Fu, Wei-Ping; Shu, Jing-Kui; Wu, Jiang-Hai; Dai, Lu-Ming

    2017-11-02

    Peripheral muscle dysfunction is an important complication in patients with chronic obstructive pulmonary disease (COPD). The objective of this study was to explore the relationship between the levels of peroxisome proliferator-activated receptor α (PPARα) mRNA expression and the respiratory function and ultrastructure of mitochondria in the vastus lateralis of patients with COPD. Vastus lateralis biopsies were performed on 14 patients with COPD and 6 control subjects with normal lung function. PPARα mRNA levels in the muscle tissue were detected by real-time PCR. A Clark oxygen electrode was used to assess mitochondrial respiratory function. Mitochondrial number, fractional area in skeletal muscle cross-sections, and Z-line width were observed via transmission electron microscopy. The PPARα mRNA expression was significantly lower in COPD patients with low body mass index (BMIL) than in both COPD patients with normal body mass index (BMIN) and controls. Mitochondrial respiratory function (assessed by respiratory control ratio) was impaired in COPD patients, particularly in BMIL. Compared with that in the control group, mitochondrial number and fractional area were lower in the BMIL group, but were maintained in the BMIN group. Further, the Z-line became narrow in the BMIL group. PPARα mRNA expression was positively related to mitochondrial respiratory function and volume density. In COPD patients with BMIN, mitochondria volume density was maintained, while respiratory function decreased, whereas both volume density and respiratory function decreased in COPD patients with BMIL. PPARα mRNA expression levels are associated with decreased mitochondrial respiratory function and volume density, which may contribute to muscle dysfunction in COPD patients.

  16. Impaired exercise performance and skeletal muscle mitochondrial function in rats with secondary carnitine deficiency

    Directory of Open Access Journals (Sweden)

    Jamal BOUITBIR

    2016-08-01

    Full Text Available Purpose: The effects of carnitine depletion upon exercise performance and skeletal muscle mitochondrial function remain largely unexplored. We therefore investigated the effect of N-trimethyl-hydrazine-3-propionate (THP, a carnitine analogue inhibiting carnitine biosynthesis and renal carnitine reabsorption, on physical performance and skeletal muscle mitochondrial function in rats.Methods: Male Sprague Dawley rats were treated daily with water (control rats; n=12 or with 20 mg/100 g body weight THP (n=12 via oral gavage for 3 weeks. Following treatment, half of the animals of each group performed an exercise test until exhaustion.Results: Distance covered and exercise performance were lower in THP-treated compared to control rats. In the oxidative soleus muscle, carnitine depletion caused atrophy (-24% and impaired function of complex II and IV of the mitochondrial electron transport chain. The free radical leak (ROS production relative to oxygen consumption was increased and the cellular glutathione pool decreased. Moreover, mRNA expression of markers of mitochondrial biogenesis and mitochondrial DNA were decreased in THP-treated compared to control rats. In comparison, in the glycolytic gastrocnemius muscle, carnitine depletion was associated with impaired function of complex IV and increased free radical leak, whilst muscle weight and cellular glutathione pool were maintained. Markers of mitochondrial proliferation and mitochondrial DNA were unaffected.Conclusions: Carnitine deficiency is associated with impaired exercise capacity in rats treated with THP. THP-induced carnitine deficiency is associated with impaired function of the electron transport chain in oxidative and glycolytic muscle as well as with atrophy and decreased mitochondrial DNA in oxidative muscle.

  17. Tubulopathy and pancytopaenia with normal pancreatic function: a variant of Pearson syndrome.

    Science.gov (United States)

    Atale, Agnès; Bonneau-Amati, Patrizia; Rötig, Agnès; Fischer, Alain; Perez-Martin, Stéphanie; de Lonlay, Pascale; Niaudet, Patrick; De Parscau, L; Mousson, C; Thauvin-Robinet, C; Munnich, A; Huet, F; Faivre, L

    2009-01-01

    Out of a series of 30 French patients with Pearson syndrome, we report on two patients with an atypical presentation, which include growth deficiency, pancytopaenia, tubulopathy and absence of exocrine pancreas dysfunction. Patient 1, a 4-year-old boy with a past history of pancytopaenia and transient metabolic acidosis at 13 months of age, presented at 2(1/2) years of age with severe tubulopathy of de Toni-Debré-Fanconi type, growth retardation, metabolic lactic acidosis and mild cytolysis. Despite normal exocrine pancreatic function, study of mitochondrial DNA revealed a 3.5 kb deletion. Patient 2 had a personal history of pancytopaenia requiring blood transfusions at 11 months of age and presented with severe intractable proximal and distal tubulopathy at 2 years of age. Exocrine pancreatic deficiency could not be evidenced and post-mortem studies revealed a 4.9 kb deletion of the mitochondrial DNA. A review of the literature revealed three patients presenting with Pearson syndrome and tubulopathy with normal pancreatic function and highlights delay in diagnosis in those three patients. The series of 30 French patients with Pearson syndrome also revealed that tubulopathy was present in 7/30 cases (23%), with variable outcome. In conclusion, Pearson syndrome should be screened for in children presenting with the association of growth retardation, anaemia/pancytopaenia, lactic acidosis and tubulopathy, even in the absence of exocrine pancreatic deficiency.

  18. Myocardial mitochondrial and contractile function are preserved in mice lacking adiponectin.

    Directory of Open Access Journals (Sweden)

    Martin Braun

    Full Text Available Adiponectin deficiency leads to increased myocardial infarct size following ischemia reperfusion and to exaggerated cardiac hypertrophy following pressure overload, entities that are causally linked to mitochondrial dysfunction. In skeletal muscle, lack of adiponectin results in impaired mitochondrial function. Thus, it was our objective to investigate whether adiponectin deficiency impairs mitochondrial energetics in the heart. At 8 weeks of age, heart weight-to-body weight ratios were not different between adiponectin knockout (ADQ-/- mice and wildtypes (WT. In isolated working hearts, cardiac output, aortic developed pressure and cardiac power were preserved in ADQ-/- mice. Rates of fatty acid oxidation, glucose oxidation and glycolysis were unchanged between groups. While myocardial oxygen consumption was slightly reduced (-24% in ADQ-/- mice in isolated working hearts, rates of maximal ADP-stimulated mitochondrial oxygen consumption and ATP synthesis in saponin-permeabilized cardiac fibers were preserved in ADQ-/- mice with glutamate, pyruvate or palmitoyl-carnitine as a substrate. In addition, enzymatic activity of respiratory complexes I and II was unchanged between groups. Phosphorylation of AMP-activated protein kinase and SIRT1 activity were not decreased, expression and acetylation of PGC-1α were unchanged, and mitochondrial content of OXPHOS subunits was not decreased in ADQ-/- mice. Finally, increasing energy demands due to prolonged subcutaneous infusion of isoproterenol did not differentially affect cardiac contractility or mitochondrial function in ADQ-/- mice compared to WT. Thus, mitochondrial and contractile function are preserved in hearts of mice lacking adiponectin, suggesting that adiponectin may be expendable in the regulation of mitochondrial energetics and contractile function in the heart under non-pathological conditions.

  19. Nuclear genomic control of naturally occurring variation in mitochondrial function in Drosophila melanogaster

    Science.gov (United States)

    2012-01-01

    Background Mitochondria are organelles found in nearly all eukaryotic cells that play a crucial role in cellular survival and function. Mitochondrial function is under the control of nuclear and mitochondrial genomes. While the latter has been the focus of most genetic research, we remain largely ignorant about the nuclear-encoded genomic control of inter-individual variability in mitochondrial function. Here, we used Drosophila melanogaster as our model organism to address this question. Results We quantified mitochondrial state 3 and state 4 respiration rates and P:O ratio in mitochondria isolated from the thoraces of 40 sequenced inbred lines of the Drosophila Genetic Reference Panel. We found significant within-population genetic variability for all mitochondrial traits. Hence, we performed genome-wide association mapping and identified 141 single nucleotide polymorphisms (SNPs) associated with differences in mitochondrial respiration and efficiency (P ≤1 × 10-5). Gene-centered regression models showed that 2–3 SNPs can explain 31, 13, and 18% of the phenotypic variation in state 3, state 4, and P:O ratio, respectively. Most of the genes tagged by the SNPs are involved in organ development, second messenger-mediated signaling pathways, and cytoskeleton remodeling. One of these genes, sallimus (sls), encodes a component of the muscle sarcomere. We confirmed the direct effect of sls on mitochondrial respiration using two viable mutants and their coisogenic wild-type strain. Furthermore, correlation network analysis revealed that sls functions as a transcriptional hub in a co-regulated module associated with mitochondrial respiration and is connected to CG7834, which is predicted to encode a protein with mitochondrial electron transfer flavoprotein activity. This latter finding was also verified in the sls mutants. Conclusions Our results provide novel insights into the genetic factors regulating natural variation in mitochondrial function in D

  20. In vivo quantification reveals extensive natural variation in mitochondrial form and function in Caenorhabditis briggsae.

    Directory of Open Access Journals (Sweden)

    Kiley A Hicks

    Full Text Available We have analyzed natural variation in mitochondrial form and function among a set of Caenorhabditis briggsae isolates known to harbor mitochondrial DNA structural variation in the form of a heteroplasmic nad5 gene deletion (nad5Δ that correlates negatively with organismal fitness. We performed in vivo quantification of 24 mitochondrial phenotypes including reactive oxygen species level, membrane potential, and aspects of organelle morphology, and observed significant among-isolate variation in 18 traits. Although several mitochondrial phenotypes were non-linearly associated with nad5Δ levels, most of the among-isolate phenotypic variation could be accounted for by phylogeographic clade membership. In particular, isolate-specific mitochondrial membrane potential was an excellent predictor of clade membership. We interpret this result in light of recent evidence for local adaptation to temperature in C. briggsae. Analysis of mitochondrial-nuclear hybrid strains provided support for both mtDNA and nuclear genetic variation as drivers of natural mitochondrial phenotype variation. This study demonstrates that multicellular eukaryotic species are capable of extensive natural variation in organellar phenotypes and highlights the potential of integrating evolutionary and cell biology perspectives.

  1. 17β-estradiol modifies human spermatozoa mitochondrial function in vitro.

    Science.gov (United States)

    Kotwicka, Malgorzata; Skibinska, Izabela; Jendraszak, Magdalena; Jedrzejczak, Piotr

    2016-08-26

    It is assumed that spermatozoa are target cells for estrogens however, the mechanism of their action is not fully understood. The aim of this study was to investigate the influence of 17β-estradiol (E2) on the human spermatozoa mitochondrial function. The effects on spermatozoa of E2 at final concentrations of 10(-10), 10(-8) and 10(-6) M were studied regarding the following phenomena: (1) kinetics of intracellular free calcium ions changes (using Fluo-3), (2) mitochondrial membrane potential ΔΨm (using JC-1 fluorochrome), (3) production of superoxide anion in mitochondria (using MitoSOX RED dye), (4) spermatozoa vitality (propidium iodide staining) and (5) phosphatidylserine membrane translocation (staining with annexin V marked with fluorescein). E2 initiated rapid (within a few seconds) dose dependent increase of intracellular free calcium ions concentration. E2 was changing the mitochondrial membrane potential: 10(-8) M initiated significant increase of percentage of high ΔΨm spermatozoa while the 10(-6) M induced significant decrease of high ΔΨm cells. In spermatozoa stimulated with E2 10(-6) M a significant increase of mitochondrial superoxide anion level was observed. 2 h incubation of spermatozoa with E2 did not alter cells vitality nor stimulated phosphatidylserine membrane translocation, for all three doses. 17β-estradiol affected the human spermatozoa mitochondrial function. E2 in low concentration improved while in high concentration might deteriorate mitochondrial function.

  2. Echinochrome A Protects Mitochondrial Function in Cardiomyocytes against Cardiotoxic Drugs

    Directory of Open Access Journals (Sweden)

    Seung Hun Jeong

    2014-05-01

    Full Text Available Echinochrome A (Ech A is a naphthoquinoid pigment from sea urchins that possesses antioxidant, antimicrobial, anti-inflammatory and chelating abilities. Although Ech A is the active substance in the ophthalmic and cardiac drug Histochrome®, its underlying cardioprotective mechanisms are not well understood. In this study, we investigated the protective role of Ech A against toxic agents that induce death of rat cardiac myoblast H9c2 cells and isolated rat cardiomyocytes. We found that the cardiotoxic agents tert-Butyl hydroperoxide (tBHP, organic reactive oxygen species (ROS inducer, sodium nitroprusside (SNP; anti-hypertension drug, and doxorubicin (anti-cancer drug caused mitochondrial dysfunction such as increased ROS level and decreased mitochondrial membrane potential. Co-treatment with Ech A, however, prevented this decrease in membrane potential and increase in ROS level. Co-treatment of Ech A also reduced the effects of these cardiotoxic agents on mitochondrial oxidative phosphorylation and adenosine triphosphate level. These findings indicate the therapeutic potential of Ech A for reducing cardiotoxic agent-induced damage.

  3. IL-15Rα deficiency in skeletal muscle alters respiratory function and the proteome of mitochondrial subpopulations independent of changes to the mitochondrial genome

    Science.gov (United States)

    O'Connell, Grant C.; Nichols, Cody; Guo, Ge; Croston, Tara L.; Thapa, Dharendra; Hollander, John M.; Pistilli, Emidio E.

    2016-01-01

    Interleukin-15 receptor alpha knockout (IL15RαKO) mice exhibit a greater skeletal muscle mitochondrial density with an altered mitochondrial morphology. However, the mechanism and functional impact of these changes have not been determined. In this study, we characterized the functional, proteomic, and genomic alterations in mitochondrial subpopulations isolated from the skeletal muscles of IL15RαKO mice and B6129 background control mice. State 3 respiration was greater in interfibrillar mitochondria and whole muscle ATP levels were greater in IL15RαKO mice supporting the increases in respiration rate. However, the state 3/state 4 ratio was lower, suggesting some degree of respiratory uncoupling. Proteomic analyses identified several markers independently in mitochondrial subpopulations that are associated with these functional alterations. Next Generation Sequencing of mtDNA revealed a high degree of similarity between the mitochondrial genomes of IL15RαKO mice and controls in terms of copy number, consensus coding and the presence of minor alleles, suggesting that the functional and proteomic alterations we observed occur independent of alterations to the mitochondrial genome. These data provide additional evidence to implicate IL-15Rα as a regulator of skeletal muscle phenotypes through effects on the mitochondrion, and suggest these effects are driven by alterations to the mitochondrial proteome. PMID:26458787

  4. S100A1: A Regulator of Striated Muscle Sarcoplasmic Reticulum Ca2+ Handling, Sarcomeric, and Mitochondrial Function

    Directory of Open Access Journals (Sweden)

    Mirko Völkers

    2010-01-01

    S100A1 has further been detected at different sites within the cardiac sarcomere indicating potential roles in myofilament function. More recently, a study reported a mitochondrial location of S100A1 in cardiomyocytes. Additionally, normalizing the level of S100A1 protein by means of viral cardiac gene transfer in animal heart failure models resulted in a disrupted progression towards cardiac failure and enhanced survival. This brief review is confined to the physiological and pathophysiological relevance of S100A1 in cardiac and skeletal muscle Ca2+ handling with a particular focus on its potential as a molecular target for future therapeutic interventions.

  5. Advances in the quantification of mitochondrial function in primary human immune cells through extracellular flux analysis.

    Directory of Open Access Journals (Sweden)

    Dequina Nicholas

    Full Text Available Numerous studies show that mitochondrial energy generation determines the effectiveness of immune responses. Furthermore, changes in mitochondrial function may regulate lymphocyte function in inflammatory diseases like type 2 diabetes. Analysis of lymphocyte mitochondrial function has been facilitated by introduction of 96-well format extracellular flux (XF96 analyzers, but the technology remains imperfect for analysis of human lymphocytes. Limitations in XF technology include the lack of practical protocols for analysis of archived human cells, and inadequate data analysis tools that require manual quality checks. Current analysis tools for XF outcomes are also unable to automatically assess data quality and delete untenable data from the relatively high number of biological replicates needed to power complex human cell studies. The objectives of work presented herein are to test the impact of common cellular manipulations on XF outcomes, and to develop and validate a new automated tool that objectively analyzes a virtually unlimited number of samples to quantitate mitochondrial function in immune cells. We present significant improvements on previous XF analyses of primary human cells that will be absolutely essential to test the prediction that changes in immune cell mitochondrial function and fuel sources support immune dysfunction in chronic inflammatory diseases like type 2 diabetes.

  6. Nutritional Ketosis and Mitohormesis: Potential Implications for Mitochondrial Function and Human Health

    Directory of Open Access Journals (Sweden)

    Vincent J. Miller

    2018-01-01

    Full Text Available Impaired mitochondrial function often results in excessive production of reactive oxygen species (ROS and is involved in the etiology of many chronic diseases, including cardiovascular disease, diabetes, neurodegenerative disorders, and cancer. Moderate levels of mitochondrial ROS, however, can protect against chronic disease by inducing upregulation of mitochondrial capacity and endogenous antioxidant defense. This phenomenon, referred to as mitohormesis, is induced through increased reliance on mitochondrial respiration, which can occur through diet or exercise. Nutritional ketosis is a safe and physiological metabolic state induced through a ketogenic diet low in carbohydrate and moderate in protein. Such a diet increases reliance on mitochondrial respiration and may, therefore, induce mitohormesis. Furthermore, the ketone β-hydroxybutyrate (BHB, which is elevated during nutritional ketosis to levels no greater than those resulting from fasting, acts as a signaling molecule in addition to its traditionally known role as an energy substrate. BHB signaling induces adaptations similar to mitohormesis, thereby expanding the potential benefit of nutritional ketosis beyond carbohydrate restriction. This review describes the evidence supporting enhancement of mitochondrial function and endogenous antioxidant defense in response to nutritional ketosis, as well as the potential mechanisms leading to these adaptations.

  7. Nutritional Ketosis and Mitohormesis: Potential Implications for Mitochondrial Function and Human Health

    Science.gov (United States)

    Villamena, Frederick A.

    2018-01-01

    Impaired mitochondrial function often results in excessive production of reactive oxygen species (ROS) and is involved in the etiology of many chronic diseases, including cardiovascular disease, diabetes, neurodegenerative disorders, and cancer. Moderate levels of mitochondrial ROS, however, can protect against chronic disease by inducing upregulation of mitochondrial capacity and endogenous antioxidant defense. This phenomenon, referred to as mitohormesis, is induced through increased reliance on mitochondrial respiration, which can occur through diet or exercise. Nutritional ketosis is a safe and physiological metabolic state induced through a ketogenic diet low in carbohydrate and moderate in protein. Such a diet increases reliance on mitochondrial respiration and may, therefore, induce mitohormesis. Furthermore, the ketone β-hydroxybutyrate (BHB), which is elevated during nutritional ketosis to levels no greater than those resulting from fasting, acts as a signaling molecule in addition to its traditionally known role as an energy substrate. BHB signaling induces adaptations similar to mitohormesis, thereby expanding the potential benefit of nutritional ketosis beyond carbohydrate restriction. This review describes the evidence supporting enhancement of mitochondrial function and endogenous antioxidant defense in response to nutritional ketosis, as well as the potential mechanisms leading to these adaptations. PMID:29607218

  8. A p300 and SIRT1 Regulated Acetylation Switch of C/EBPα Controls Mitochondrial Function

    Directory of Open Access Journals (Sweden)

    Mohamad A. Zaini

    2018-01-01

    Full Text Available Summary: Cellular metabolism is a tightly controlled process in which the cell adapts fluxes through metabolic pathways in response to changes in nutrient supply. Among the transcription factors that regulate gene expression and thereby cause changes in cellular metabolism is the basic leucine-zipper (bZIP transcription factor CCAAT/enhancer-binding protein alpha (C/EBPα. Protein lysine acetylation is a key post-translational modification (PTM that integrates cellular metabolic cues with other physiological processes. Here, we show that C/EBPα is acetylated by the lysine acetyl transferase (KAT p300 and deacetylated by the lysine deacetylase (KDAC sirtuin1 (SIRT1. SIRT1 is activated in times of energy demand by high levels of nicotinamide adenine dinucleotide (NAD+ and controls mitochondrial biogenesis and function. A hypoacetylated mutant of C/EBPα induces the transcription of mitochondrial genes and results in increased mitochondrial respiration. Our study identifies C/EBPα as a key mediator of SIRT1-controlled adaption of energy homeostasis to changes in nutrient supply. : Zaini et al. show that the transcription factor C/EBPα is acetylated by p300 and deacetylated by the lysine deacetylase SIRT1. Hypoacetylated C/EBPα induces the transcription of mitochondrial genes and results in increased mitochondrial respiration. C/EBPα is a key mediator of SIRT1-controlled adaption of energy homeostasis to changes in nutrient supply. Keywords: C/EBPα, SIRT1, p300, lysine acetylation, mitochondrial function, cellular metabolism, NAD+, gene regulation

  9. Intracellular expression of Tat alters mitochondrial functions in T cells: a potential mechanism to understand mitochondrial damage during HIV-1 replication

    OpenAIRE

    Rodríguez-Mora, Sara; Mateos, Elena; Moran, María; Martín, Miguel Ángel; López, Juan Antonio; Calvo, Enrique; Terrón, María Carmen; Luque, Daniel; Muriaux, Delphine; Alcamí, José; Coiras, Mayte; López-Huertas, María Rosa

    2015-01-01

    Background HIV-1 replication results in mitochondrial damage that is enhanced during antiretroviral therapy (ART). The onset of HIV-1 replication is regulated by viral protein Tat, a 101-residue protein codified by two exons that elongates viral transcripts. Although the first exon of Tat (aa 1–72) forms itself an active protein, the presence of the second exon (aa 73–101) results in a more competent transcriptional protein with additional functions. Results Mitochondrial overall functions we...

  10. Effect of rosiglitazone on cardiac electrophysiology, infarct size and mitochondrial function in ischaemia and reperfusion of swine and rat heart.

    Science.gov (United States)

    Palee, Siripong; Weerateerangkul, Punate; Surinkeaw, Sirirat; Chattipakorn, Siriporn; Chattipakorn, Nipon

    2011-08-01

    Rosiglitazone, a peroxisome proliferator-activated receptor γ agonist, has been used to treat type 2 diabetes. Despite debates regarding its cardioprotection, the effects of rosiglitazone on cardiac electrophysiology are still unclear. This study determined the effect of rosiglitazone on ventricular fibrillation (VF) incidence, VF threshold (VFT), defibrillation threshold (DFT) and mitochondrial function during ischaemia and reperfusion. Twenty-six pigs were used. In each pig, either rosiglitazone (1 mg kg(-1)) or normal saline solution was administered intravenously for 60 min. Then, the left anterior descending coronary artery was ligated for 60 min and released to promote reperfusion for 120 min. The cardiac electrophysiological parameters were determined at the beginning of the study and during the ischaemia and reperfusion periods. The heart was removed, and the area at risk and infarct size in each heart were determined. Cardiac mitochondria were isolated for determination of mitochondrial function. Rosiglitazone did not improve the DFT and VFT during the ischaemia-reperfusion period. In the rosiglitazone group, the VF incidence was increased (58 versus 10%) and the time to the first occurrence of VF was decreased (3 ± 2 versus 19 ± 1 min) in comparison to the vehicle group (P < 0.05). However, the infarct size related to the area at risk in the rosiglitazone group was significantly decreased (P < 0.05). In the cardiac mitochondria, rosiglitazone did not alter the level of production of reactive oxygen species and could not prevent mitochondrial membrane potential changes. Rosiglitazone increased the propensity for VF, and could neither increase defibrillation efficacy nor improve cardiac mitochondrial function.

  11. Nonphotochemical Hole-Burning Imaging Studies of in vitro Carcinoma and Normal Cells Utilizing a Mitochondrial Specific Dye

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Richard Joseph [Iowa State Univ., Ames, IA (United States)

    2002-01-01

    Low temperature Nonphotochemical Hole Burning (NPHB) Spectroscopy of the dye rhodamine 800 (MF680) was applied for the purpose of discerning differences between cultured normal and carcinoma ovarian surface epithelial (OSE) cells. Both the cell lines were developed and characterized at the Mayo Clinic (Rochester, MN), with the normal cell line having been transfected with a strain of temperature sensitive Simian Virus 40 Large T Antigen (SV40) for the purpose of extending the life of the cell culture without inducing permanent changes in the characteristics of the cell line. The cationic lipophilic fluorophore rhodamine 800 preferentially locates in in situ mitochondria due to the high lipid composition of mitochondria and the generation of a large negative membrane potential (relative to the cellular cytoplasm) for oxidative phosphorylation. Results presented for NPHB of MF680 located in the cells show significant differences between the two cell lines. The results are interpreted on the basis of the NPHB mechanism and characteristic interactions between the host (cellular mitochondrial) and the guest (MF680) in the burning of spectral holes, thus providing an image of the cellular ultrastructure. Hole growth kinetics (HGK) were found to differ markedly between the two cell lines, with the carcinoma cell line burning at a faster average rate for the same exposure fluence. Theoretical fits to the data suggest a lower degree of structural heterogeneity in the carcinoma cell line relative to the normal cell line. Measurement of changes in the permanent dipole moment (fΔμ) were accomplished by measurement of changes in hole width in response to the application of an external electric field (the Stark effect), and found that Δμ values for the carcinoma line were 1.5x greater than those of the SV40 antigen-free normal analogs. These findings are interpreted in terms of effects from the mitochondrial membrane potential. Results for HGK on the scale of single cells is

  12. Nonphotochemical Hole-Burning Imaging Studies of In Vitro Carcinoma and Normal Cells Utilizing a Mitochondrial Specific Dye

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Richard Joseph [Iowa State Univ., Ames, IA (United States)

    2002-01-01

    Low temperature Nonphotochemical Hole Burning (NPHB) Spectroscopy of the dye rhodamine 800 (MF680) was applied for the purpose of discerning differences between cultured normal and carcinoma ovarian surface epithelial (OSE) cells. Both the cell lines were developed and characterized at the Mayo Clinic (Rochester, MN), with the normal cell line having been transfected with a strain of temperature sensitive Simian Virus 40 Large T Antigen (SV40) for the purpose of extending the life of the cell culture without inducing permanent changes in the characteristics of the cell line. The cationic lipophilic fluorophore rhodamine 800 preferentially locates in in situ mitochondria due to the high lipid composition of mitochondria and the generation of a large negative membrane potential (relative to the cellular cytoplasm) for oxidative phosphorylation. Results presented for NPHB of MF680 located in the cells show significant differences between the two cell lines. The results are interpreted on the basis of the NPHB mechanism and characteristic interactions between the host (cellular mitochondrial) and the guest (MF680) in the burning of spectral holes, thus providing an image of the cellular ultrastructure. Hole growth kinetics (HGK) were found to differ markedly between the two cell lines, with the carcinoma cell line burning at a faster average rate for the same exposure fluence. Theoretical fits to the data suggest a lower degree of structural heterogeneity in the carcinoma cell line relative to the normal cell line. Measurement of changes in the permanent dipole moment (fΔμ)were accomplished by measurement of changes in hole width in response to the application of an external electric field (the Stark effect), and found that Δμ values for the carcinoma line were 1.5x greater than those of the SV40 antigen-free normal analogs. These findings are interpreted in terms of effects from the mitochondrial membrane potential. Results for HGK on the scale of single cells is

  13. Experimental studies of mitochondrial function in CADASIL vascular smooth muscle cells

    Energy Technology Data Exchange (ETDEWEB)

    Viitanen, Matti [Division of Clinical Geriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm (Sweden); Department of Geriatrics, Turku City Hospital and University of Turku, Turku (Finland); Sundström, Erik [Division of Neurodegeneration, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm (Sweden); Baumann, Marc [Protein Chemistry Unit, Institute of Biomedicine/Anatomy, University of Helsinki, Helsinki (Finland); Poyhonen, Minna [Department of Clinical Genetics, Helsinki University Hospital, HUSLAB, Helsinki (Finland); Tikka, Saara [Protein Chemistry Unit, Institute of Biomedicine/Anatomy, University of Helsinki, Helsinki (Finland); Behbahani, Homira, E-mail: homira.behbahani@ki.se [Division of Clinical Geriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm (Sweden); Karolinska Institutet Alzheimer' s Disease Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm (Sweden)

    2013-02-01

    Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is a familiar fatal progressive degenerative disorder characterized by cognitive decline, and recurrent stroke in young adults. Pathological features include a dramatic reduction of brain vascular smooth muscle cells and severe arteriopathy with the presence of granular osmophilic material in the arterial walls. Here we have investigated the cellular and mitochondrial function in vascular smooth muscle cell lines (VSMCs) established from CADASIL mutation carriers (R133C) and healthy controls. We found significantly lower proliferation rates in CADASIL VSMC as compared to VSMC from controls. Cultured CADASIL VSMCs were not more vulnerable than control cells to a number of toxic substances. Morphological studies showed reduced mitochondrial connectivity and increased number of mitochondria in CADASIL VSMCs. Transmission electron microscopy analysis demonstrated increased irregular and abnormal mitochondria in CADASIL VSMCs. Measurements of mitochondrial membrane potential (Δψ{sub m}) showed a lower percentage of fully functional mitochondria in CADASIL VSMCs. For a number of genes previously reported to be changed in CADASIL VSMCs, immunoblotting analysis demonstrated a significantly reduced SOD1 expression. These findings suggest that alteration of proliferation and mitochondrial function in CADASIL VSMCs might have an effect on vital cellular functions important for CADASIL pathology. -- Highlights: ► CADASIL is an inherited disease of cerebral vascular cells. ► Mitochondrial dysfunction has been implicated in the pathogenesis of CADASIL. ► Lower proliferation rates in CADASIL VSMC. ► Increased irregular and abnormal mitochondria and lower mitochondrial membrane potential in CADASIL VSMCs. ► Reduced mitochondrial connectivity and increased number of mitochondria in CADASIL VSMCs.

  14. Experimental studies of mitochondrial function in CADASIL vascular smooth muscle cells

    International Nuclear Information System (INIS)

    Viitanen, Matti; Sundström, Erik; Baumann, Marc; Poyhonen, Minna; Tikka, Saara; Behbahani, Homira

    2013-01-01

    Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is a familiar fatal progressive degenerative disorder characterized by cognitive decline, and recurrent stroke in young adults. Pathological features include a dramatic reduction of brain vascular smooth muscle cells and severe arteriopathy with the presence of granular osmophilic material in the arterial walls. Here we have investigated the cellular and mitochondrial function in vascular smooth muscle cell lines (VSMCs) established from CADASIL mutation carriers (R133C) and healthy controls. We found significantly lower proliferation rates in CADASIL VSMC as compared to VSMC from controls. Cultured CADASIL VSMCs were not more vulnerable than control cells to a number of toxic substances. Morphological studies showed reduced mitochondrial connectivity and increased number of mitochondria in CADASIL VSMCs. Transmission electron microscopy analysis demonstrated increased irregular and abnormal mitochondria in CADASIL VSMCs. Measurements of mitochondrial membrane potential (Δψ m ) showed a lower percentage of fully functional mitochondria in CADASIL VSMCs. For a number of genes previously reported to be changed in CADASIL VSMCs, immunoblotting analysis demonstrated a significantly reduced SOD1 expression. These findings suggest that alteration of proliferation and mitochondrial function in CADASIL VSMCs might have an effect on vital cellular functions important for CADASIL pathology. -- Highlights: ► CADASIL is an inherited disease of cerebral vascular cells. ► Mitochondrial dysfunction has been implicated in the pathogenesis of CADASIL. ► Lower proliferation rates in CADASIL VSMC. ► Increased irregular and abnormal mitochondria and lower mitochondrial membrane potential in CADASIL VSMCs. ► Reduced mitochondrial connectivity and increased number of mitochondria in CADASIL VSMCs.

  15. Insulin stimulates mitochondrial fusion and function in cardiomyocytes via the Akt-mTOR-NFκB-Opa-1 signaling pathway.

    Science.gov (United States)

    Parra, Valentina; Verdejo, Hugo E; Iglewski, Myriam; Del Campo, Andrea; Troncoso, Rodrigo; Jones, Deborah; Zhu, Yi; Kuzmicic, Jovan; Pennanen, Christian; Lopez-Crisosto, Camila; Jaña, Fabián; Ferreira, Jorge; Noguera, Eduard; Chiong, Mario; Bernlohr, David A; Klip, Amira; Hill, Joseph A; Rothermel, Beverly A; Abel, Evan Dale; Zorzano, Antonio; Lavandero, Sergio

    2014-01-01

    Insulin regulates heart metabolism through the regulation of insulin-stimulated glucose uptake. Studies have indicated that insulin can also regulate mitochondrial function. Relevant to this idea, mitochondrial function is impaired in diabetic individuals. Furthermore, the expression of Opa-1 and mitofusins, proteins of the mitochondrial fusion machinery, is dramatically altered in obese and insulin-resistant patients. Given the role of insulin in the control of cardiac energetics, the goal of this study was to investigate whether insulin affects mitochondrial dynamics in cardiomyocytes. Confocal microscopy and the mitochondrial dye MitoTracker Green were used to obtain three-dimensional images of the mitochondrial network in cardiomyocytes and L6 skeletal muscle cells in culture. Three hours of insulin treatment increased Opa-1 protein levels, promoted mitochondrial fusion, increased mitochondrial membrane potential, and elevated both intracellular ATP levels and oxygen consumption in cardiomyocytes in vitro and in vivo. Consequently, the silencing of Opa-1 or Mfn2 prevented all the metabolic effects triggered by insulin. We also provide evidence indicating that insulin increases mitochondrial function in cardiomyocytes through the Akt-mTOR-NFκB signaling pathway. These data demonstrate for the first time in our knowledge that insulin acutely regulates mitochondrial metabolism in cardiomyocytes through a mechanism that depends on increased mitochondrial fusion, Opa-1, and the Akt-mTOR-NFκB pathway.

  16. Role of Sex Hormones on Brain Mitochondrial Function, with Special Reference to Aging and Neurodegenerative Diseases

    Directory of Open Access Journals (Sweden)

    Pauline Gaignard

    2017-12-01

    Full Text Available The mitochondria have a fundamental role in both cellular energy supply and oxidative stress regulation and are target of the effects of sex steroids, particularly the neuroprotective ones. Aging is associated with a decline in the levels of different steroid hormones, and this decrease may underline some neural dysfunctions. Besides, modifications in mitochondrial functions associated with aging processes are also well documented. In this review, we will discuss studies that describe the modifications of brain mitochondrial function and of steroid levels associated with physiological aging and with neurodegenerative diseases. A special emphasis will be placed on describing and discussing our recent findings concerning the concomitant study of mitochondrial function (oxidative phosphorylation, oxidative stress and brain steroid levels in both young (3-month-old and aged (20-month-old male and female mice.

  17. Physical activity unveils the relationship between mitochondrial energetics, muscle quality, and physical function in older adults.

    Science.gov (United States)

    Distefano, Giovanna; Standley, Robert A; Zhang, Xiaolei; Carnero, Elvis A; Yi, Fanchao; Cornnell, Heather H; Coen, Paul M

    2018-01-24

    The concept of mitochondrial dysfunction in ageing muscle is highly controversial. In addition, emerging evidence suggests that reduced muscle oxidative capacity and efficiency underlie the aetiology of mobility loss in older adults. Here, we hypothesized that studying well-phenotyped older cohorts across a wide range of physical activity would unveil a range of mitochondrial function in skeletal muscle and in turn allow us to more clearly examine the impact of age per se on mitochondrial energetics. This also enabled us to more clearly define the relationships between mitochondrial energetics and muscle lipid content with clinically relevant assessments of muscle and physical function. Thirty-nine volunteers were recruited to the following study groups: young active (YA, n = 2 women/8 men, age = 31.2 ± 5.4 years), older active (OA, n = 2 women/8 men, age = 67.5 ± 2.7 years), and older sedentary (OS, n = 8 women/11 men, age = 70.7 ± 4.7 years). Participants completed a graded exercise test to determine fitness (VO 2 peak), a submaximal exercise test to determine exercise efficiency, and daily physical activity was recorded using a tri-axial armband accelerometer. Mitochondrial energetics were determined by (i) 31 P magnetic resonance spectroscopy and (ii) respirometry of fibre bundles from vastus lateralis biopsies. Quadriceps function was assessed by isokinetic dynamometry and physical function by the short physical performance battery and stair climb test. Daily physical activity energy expenditure was significantly lower in OS, compared with YA and OA groups. Despite fitness being higher in YA compared with OA and OS, mitochondrial respiration, maximum mitochondrial capacity, Maximal ATP production/Oxygen consumption (P/O) ratio, and exercise efficiency were similar in YA and OA groups and were significantly lower in OS. P/O ratio was correlated with exercise efficiency. Time to complete the stair climb and repeated chair stand tests were

  18. Testosterone plus low-intensity physical training in late life improves functional performance, skeletal muscle mitochondrial biogenesis, and mitochondrial quality control in male mice.

    Directory of Open Access Journals (Sweden)

    Wen Guo

    Full Text Available Testosterone supplementation increases muscle mass in older men but has not been shown to consistently improve physical function and activity. It has been hypothesized that physical exercise is required to induce the adaptations necessary for translation of testosterone-induced muscle mass gain into functional improvements. However, the effects of testosterone plus low intensity physical exercise training (T/PT on functional performance and bioenergetics are unknown. In this pilot study, we tested the hypothesis that combined administration of T/PT would improve functional performance and bioenergetics in male mice late in life more than low-intensity physical training alone. 28-month old male mice were randomized to receive T/PT or vehicle plus physical training (V/PT for 2 months. Compare to V/PT control, administration of T/PT was associated with improvements in muscle mass, grip strength, spontaneous physical movements, and respiratory activity. These changes were correlated with increased mitochondrial DNA copy number and expression of markers for mitochondrial biogenesis. Mice receiving T/PT also displayed increased expression of key elements for mitochondrial quality control, including markers for mitochondrial fission-and-fusion and mitophagy. Concurrently, mice receiving T/PT also displayed increased expression of markers for reduced tissue oxidative damage and improved muscle quality.Testosterone administered with low-intensity physical training improves grip strength, spontaneous movements, and respiratory activity. These functional improvements were associated with increased muscle mitochondrial biogenesis and improved mitochondrial quality control.

  19. A mitochondrial GABA permease connects the GABA shunt and the TCA cycle, and is essential for normal carbon metabolism.

    Science.gov (United States)

    Michaeli, Simon; Fait, Aaron; Lagor, Kelly; Nunes-Nesi, Adriano; Grillich, Nicole; Yellin, Ayelet; Bar, Dana; Khan, Munziba; Fernie, Alisdair R; Turano, Frank J; Fromm, Hillel

    2011-08-01

    In plants, γ-aminobutyric acid (GABA) accumulates in the cytosol in response to a variety of stresses. GABA is transported into mitochondria, where it is catabolized into TCA cycle or other intermediates. Although there is circumstantial evidence for mitochondrial GABA transporters in eukaryotes, none have yet been identified. Described here is an Arabidopsis protein similar in sequence and topology to unicellular GABA transporters. The expression of this protein complements a GABA-transport-deficient yeast mutant. Thus the protein was termed AtGABP to indicate GABA-permease activity. In vivo localization of GABP fused to GFP and immunobloting of subcellular fractions demonstrate its mitochondrial localization. Direct [(3) H]GABA uptake measurements into isolated mitochondria revealed impaired uptake into mitochondria of a gabp mutant compared with wild-type (WT) mitochondria, implicating AtGABP as a major mitochondrial GABA carrier. Measurements of CO(2) release, derived from radiolabeled substrates in whole seedlings and in isolated mitochondria, demonstrate impaired GABA-derived input into the TCA cycle, and a compensatory increase in TCA cycle activity in gabp mutants. Finally, growth abnormalities of gabp mutants under limited carbon availability on artificial media, and in soil under low light intensity, combined with their metabolite profiles, suggest an important role for AtGABP in primary carbon metabolism and plant growth. Thus, AtGABP-mediated transport of GABA from the cytosol into mitochondria is important to ensure proper GABA-mediated respiration and carbon metabolism. This function is particularly essential for plant growth under conditions of limited carbon. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

  20. Melatonin enhances neural stem cell differentiation and engraftment by increasing mitochondrial function.

    Science.gov (United States)

    Mendivil-Perez, Miguel; Soto-Mercado, Viviana; Guerra-Librero, Ana; Fernandez-Gil, Beatriz I; Florido, Javier; Shen, Ying-Qiang; Tejada, Miguel A; Capilla-Gonzalez, Vivian; Rusanova, Iryna; Garcia-Verdugo, José M; Acuña-Castroviejo, Darío; López, Luis Carlos; Velez-Pardo, Carlos; Jimenez-Del-Rio, Marlene; Ferrer, José M; Escames, Germaine

    2017-09-01

    Neural stem cells (NSCs) are regarded as a promising therapeutic approach to protecting and restoring damaged neurons in neurodegenerative diseases (NDs) such as Parkinson's disease and Alzheimer's disease (PD and AD, respectively). However, new research suggests that NSC differentiation is required to make this strategy effective. Several studies have demonstrated that melatonin increases mature neuronal markers, which reflects NSC differentiation into neurons. Nevertheless, the possible involvement of mitochondria in the effects of melatonin during NSC differentiation has not yet been fully established. We therefore tested the impact of melatonin on NSC proliferation and differentiation in an attempt to determine whether these actions depend on modulating mitochondrial activity. We measured proliferation and differentiation markers, mitochondrial structural and functional parameters as well as oxidative stress indicators and also evaluated cell transplant engraftment. This enabled us to show that melatonin (25 μM) induces NSC differentiation into oligodendrocytes and neurons. These effects depend on increased mitochondrial mass/DNA/complexes, mitochondrial respiration, and membrane potential as well as ATP synthesis in NSCs. It is also interesting to note that melatonin prevented oxidative stress caused by high levels of mitochondrial activity. Finally, we found that melatonin enriches NSC engraftment in the ND mouse model following transplantation. We concluded that a combined therapy involving transplantation of NSCs pretreated with pharmacological doses of melatonin could efficiently restore neuronal cell populations in PD and AD mouse models depending on mitochondrial activity promotion. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Coordinated Evolution of Transcriptional and Post-Transcriptional Regulation for Mitochondrial Functions in Yeast Strains.

    Directory of Open Access Journals (Sweden)

    Xuepeng Sun

    Full Text Available Evolution of gene regulation has been proposed to play an important role in environmental adaptation. Exploring mechanisms underlying coordinated evolutionary changes at various levels of gene regulation could shed new light on how organism adapt in nature. In this study, we focused on regulatory differences between a laboratory Saccharomyces cerevisiae strain BY4742 and a pathogenic S. cerevisiae strain, YJM789. The two strains diverge in many features, including growth rate, morphology, high temperature tolerance, and pathogenicity. Our RNA-Seq and ribosomal footprint profiling data showed that gene expression differences are pervasive, and genes functioning in mitochondria are mostly divergent between the two strains at both transcriptional and translational levels. Combining functional genomics data from other yeast strains, we further demonstrated that significant divergence of expression for genes functioning in the electron transport chain (ETC was likely caused by differential expression of a transcriptional factor, HAP4, and that post-transcriptional regulation mediated by an RNA-binding protein, PUF3, likely led to expression divergence for genes involved in mitochondrial translation. We also explored mito-nuclear interactions via mitochondrial DNA replacement between strains. Although the two mitochondrial genomes harbor substantial sequence divergence, neither growth nor gene expression were affected by mitochondrial DNA replacement in both fermentative and respiratory growth media, indicating compatible mitochondrial and nuclear genomes between these two strains in the tested conditions. Collectively, we used mitochondrial functions as an example to demonstrate for the first time that evolution at both transcriptional and post-transcriptional levels could lead to coordinated regulatory changes underlying strain specific functional variations.

  2. Normalization methods in time series of platelet function assays

    Science.gov (United States)

    Van Poucke, Sven; Zhang, Zhongheng; Roest, Mark; Vukicevic, Milan; Beran, Maud; Lauwereins, Bart; Zheng, Ming-Hua; Henskens, Yvonne; Lancé, Marcus; Marcus, Abraham

    2016-01-01

    Abstract Platelet function can be quantitatively assessed by specific assays such as light-transmission aggregometry, multiple-electrode aggregometry measuring the response to adenosine diphosphate (ADP), arachidonic acid, collagen, and thrombin-receptor activating peptide and viscoelastic tests such as rotational thromboelastometry (ROTEM). The task of extracting meaningful statistical and clinical information from high-dimensional data spaces in temporal multivariate clinical data represented in multivariate time series is complex. Building insightful visualizations for multivariate time series demands adequate usage of normalization techniques. In this article, various methods for data normalization (z-transformation, range transformation, proportion transformation, and interquartile range) are presented and visualized discussing the most suited approach for platelet function data series. Normalization was calculated per assay (test) for all time points and per time point for all tests. Interquartile range, range transformation, and z-transformation demonstrated the correlation as calculated by the Spearman correlation test, when normalized per assay (test) for all time points. When normalizing per time point for all tests, no correlation could be abstracted from the charts as was the case when using all data as 1 dataset for normalization. PMID:27428217

  3. Melatonin and mitochondrial function during ischemia/reperfusion injury.

    Science.gov (United States)

    Ma, Zhiqiang; Xin, Zhenlong; Di, Wencheng; Yan, Xiaolong; Li, Xiaofei; Reiter, Russel J; Yang, Yang

    2017-11-01

    Ischemia/reperfusion (IR) injury occurs in many organs and tissues, and contributes to morbidity and mortality worldwide. Melatonin, an endogenously produced indolamine, provides a strong defense against IR injury. Mitochondrion, an organelle for ATP production and a decider for cell fate, has been validated to be a crucial target for melatonin to exert its protection against IR injury. In this review, we first clarify the mechanisms underlying mitochondrial dysfunction during IR and melatonin's protection of mitochondria under this condition. Thereafter, special focus is placed on the protective actions of melatonin against IR injury in brain, heart, liver, and others. Finally, we explore several potential future directions of research in this area. Collectively, the information compiled here will serve as a comprehensive reference for the actions of melatonin in IR injury identified to date and will hopefully aid in the design of future research and increase the potential of melatonin as a therapeutic agent.

  4. Permeabilization of brain tissue in situ enables multiregion analysis of mitochondrial function in a single mouse brain.

    Science.gov (United States)

    Herbst, Eric A F; Holloway, Graham P

    2015-02-15

    Mitochondrial function in the brain is traditionally assessed through analysing respiration in isolated mitochondria, a technique that possesses significant tissue and time requirements while also disrupting the cooperative mitochondrial reticulum. We permeabilized brain tissue in situ to permit analysis of mitochondrial respiration with the native mitochondrial morphology intact, removing the need for isolation time and minimizing tissue requirements to ∼2 mg wet weight. The permeabilized brain technique was validated against the traditional method of isolated mitochondria and was then further applied to assess regional variation in the mouse brain with ischaemia-reperfusion injuries. A transgenic mouse model overexpressing catalase within mitochondria was applied to show the contribution of mitochondrial reactive oxygen species to ischaemia-reperfusion injuries in different brain regions. This technique enhances the accessibility of addressing physiological questions in small brain regions and in applying transgenic mouse models to assess mechanisms regulating mitochondrial function in health and disease. Mitochondria function as the core energy providers in the brain and symptoms of neurodegenerative diseases are often attributed to their dysregulation. Assessing mitochondrial function is classically performed in isolated mitochondria; however, this process requires significant isolation time, demand for abundant tissue and disruption of the cooperative mitochondrial reticulum, all of which reduce reliability when attempting to assess in vivo mitochondrial bioenergetics. Here we introduce a method that advances the assessment of mitochondrial respiration in the brain by permeabilizing existing brain tissue to grant direct access to the mitochondrial reticulum in situ. The permeabilized brain preparation allows for instant analysis of mitochondrial function with unaltered mitochondrial morphology using significantly small sample sizes (∼2 mg), which permits

  5. Myocardial iron content and mitochondrial function in human heart failure: a direct tissue analysis.

    Science.gov (United States)

    Melenovsky, Vojtech; Petrak, Jiri; Mracek, Tomas; Benes, Jan; Borlaug, Barry A; Nuskova, Hana; Pluhacek, Tomas; Spatenka, Jaroslav; Kovalcikova, Jana; Drahota, Zdenek; Kautzner, Josef; Pirk, Jan; Houstek, Josef

    2017-04-01

    Iron replacement improves clinical status in iron-deficient patients with heart failure (HF), but the pathophysiology is poorly understood. Iron is essential not only for erythropoiesis, but also for cellular bioenergetics. The impact of myocardial iron deficiency (MID) on mitochondrial function, measured directly in the failing human heart, is unknown. Left ventricular samples were obtained from 91 consecutive HF patients undergoing transplantation and 38 HF-free organ donors (controls). Total myocardial iron content, mitochondrial respiration, citric acid cycle and respiratory chain enzyme activities, respiratory chain components (complex I-V), and protein content of reactive oxygen species (ROS)-protective enzymes were measured in tissue homogenates to quantify mitochondrial function. Myocardial iron content was lower in HF compared with controls (156 ± 41 vs. 200 ± 38 µg·g -1 dry weight, P Heart Failure © 2016 European Society of Cardiology.

  6. Low-Normal Thyroid Function and Novel Cardiometabolic Biomarkers

    NARCIS (Netherlands)

    van Tienhoven-Wind, Lynnda J. N.; Dullaart, Robin P. F.

    The concept is emerging that low-normal thyroid function, i.e., either higher thyroid-stimulating hormone or lower free thyroxine levels within the euthyroid reference range, could contribute to the development of atherosclerotic cardiovascular disease. It is possible that adverse effects of

  7. Normal left ventricular function does not protect against propafenone ...

    African Journals Online (AJOL)

    Normal left ventricular function does not protect against propafenone-induced incessant ventricular tachycardia. R. N. Scott Millar, J. B. Lawrenson, D.A. Milne. Abstract. Propafenone is a class Ic anti-arrhythmic agent with mild B-blocking properties which has recently become available in South Africa. We have used the ...

  8. L-carnitine exposure and mitochondrial function in human neuronal cells.

    Science.gov (United States)

    Geier, David A; Geier, Mark R

    2013-11-01

    L-Carnitine is a naturally occurring substance required in mammalian energy metabolism that functions by facilitating long-chain fatty acid entry into cellular mitochondria, thereby delivering substrate for oxidation and subsequent energy production. It has been purposed that L-carnitine may improve and preserve cognitive performance, and may lead to better cognitive aging through the life span, and several controlled human clinical trials with L-carnitine support the hypothesis that this substance has the ability to improve cognitive function. We further hypothesized that, since L-carnitine is an important co-factor of mammalian mitochondrial energy metabolism, acute administration of L-carnitine to human tissue culture cells should result in detectable increases in mitochondrial function. Cultures of SH-SY-5Y human neuroblastoma and 1321N1 human astrocytoma cells grown in 96-well cell culture plates were acutely administered L-carnitine hydrochloride, and then, mitochondrial function was assayed using the colorimetric 2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxyanilide inner salt cell assay kit in a VERSAmax tunable microplate reader. Significant increases in mitochondrial function were observed when human neuroblastoma or human astrocytoma cells were exposed to 100 nM (20 μg L-carnitine hydrochloride/L) to 100 μM (20 mg L-carnitine hydrochloride/L) concentrations of L-carnitine hydrochloride in comparison to unexposed cells, whereas no significant positive effects were observed at lower or higher concentrations of L-carnitine hydrochloride. The results of the present study provide insights for how L-carnitine therapy may significantly improve human neuronal function, but we recommend that future studies further explore different derivatives of L-carnitine compounds in different in vitro cell-based systems using different markers of mitochondrial function.

  9. Brain mitochondrial function in a murine model of cerebral malaria and the therapeutic effects of rhEPO

    DEFF Research Database (Denmark)

    Karlsson, Michael; Hempel, Casper; Sjövall, Fredrik

    2013-01-01

    and no connection between disease severity and mitochondrial respiratory function. Treatment with rhEPO similarly had no effect on respiratory function. Thus cerebral metabolic dysfunction in CM does not seem to be directly linked to altered mitochondrial respiratory capacity as analyzed in brain homogenates ex...

  10. Visualization of mitochondrial respiratory function using cytochrome c oxidase/succinate dehydrogenase (COX/SDH) double-labeling histochemistry.

    Science.gov (United States)

    Ross, Jaime M

    2011-11-23

    Mitochondrial DNA (mtDNA) defects are an important cause of disease and may underlie aging and aging-related alterations (1,2). The mitochondrial theory of aging suggests a role for mtDNA mutations, which can alter bioenergetics homeostasis and cellular function, in the aging process (3). A wealth of evidence has been compiled in support of this theory (1,4), an example being the mtDNA mutator mouse (5); however, the precise role of mtDNA damage in aging is not entirely understood (6,7). Observing the activity of respiratory enzymes is a straightforward approach for investigating mitochondrial dysfunction. Complex IV, or cytochrome c oxidase (COX), is essential for mitochondrial function. The catalytic subunits of COX are encoded by mtDNA and are essential for assembly of the complex (Figure 1). Thus, proper synthesis and function are largely based on mtDNA integrity (2). Although other respiratory complexes could be investigated, Complexes IV and II are the most amenable to histochemical examination (8,9). Complex II, or succinate dehydrogenase (SDH), is entirely encoded by nuclear DNA (Figure 1), and its activity is typically not affected by impaired mtDNA, although an increase might indicate mitochondrial biogenesis (10-12). The impaired mtDNA observed in mitochondrial diseases, aging, and age-related diseases often leads to the presence of cells with low or absent COX activity (2,12-14). Although COX and SDH activities can be investigated individually, the sequential double-labeling method (15,16) has proved to be advantageous in locating cells with mitochondrial dysfunction (12,17-21). Many of the optimal constitutions of the assay have been determined, such as substrate concentration, electron acceptors/donors, intermediate electron carriers, influence of pH, and reaction time (9,22,23). 3,3'-diaminobenzidine (DAB) is an effective and reliable electron donor (22). In cells with functioning COX, the brown indamine polymer product will localize in mitochondrial

  11. Oxidative stress and mitochondrial functions in the intestinal Caco-2/15 cell line.

    Directory of Open Access Journals (Sweden)

    Rame Taha

    2010-07-01

    Full Text Available Although mitochondrial dysfunction and oxidative stress are central mechanisms in various pathological conditions, they have not been extensively studied in the gastrointestinal tract, which is known to be constantly exposed to luminal oxidants from ingested foods. Key among these is the simultaneous consumption of iron salts and ascorbic acid, which can cause oxidative damage to biomolecules.The objective of the present work was to evaluate how iron-ascorbate (FE/ASC-mediated lipid peroxidation affects mitochondrion functioning in Caco-2/15 cells. Our results show that treatment of Caco-2/15 cells with FE/ASC (0.2 mM/2 mM (1 increased malondialdehyde levels assessed by HPLC; (2 reduced ATP production noted by luminescence assay; (3 provoked dysregulation of mitochondrial calcium homeostasis as evidenced by confocal fluorescence microscopy; (4 upregulated the protein expression of cytochrome C and apoptotic inducing factor, indicating exaggerated apoptosis; (5 affected mitochondrial respiratory chain complexes I, II, III and IV; (6 elicited mtDNA lesions as illustrated by the raised levels of 8-OHdG; (7 lowered DNA glycosylase, one of the first lines of defense against 8-OHdG mutagenicity; and (8 altered the gene expression and protein mass of mitochondrial transcription factors (mtTFA, mtTFB1, mtTFB2 without any effects on RNA Polymerase. The presence of the powerful antioxidant BHT (50 microM prevented the occurrence of oxidative stress and most of the mitochondrial abnormalities.Collectively, our findings indicate that acute exposure of Caco-2/15 cells to FE/ASC-catalyzed peroxidation produces harmful effects on mitochondrial functions and DNA integrity, which are abrogated by the powerful exogenous BHT antioxidant. Functional derangements of mitochondria may have implications in oxidative stress-related disorders such as inflammatory bowel diseases.

  12. Pharmacological Inhibition of poly(ADP-ribose) polymerases improves fitness and mitochondrial function in skeletal muscle.

    NARCIS (Netherlands)

    Pirinen, E.; Canto, C.; Jo, Y.S.; Morato, L.; Zhang, H.; Menzies, K.J.; Williams, E.G.; Mouchiroud, L.; Moullan, N.; Hagberg, C.; Li, W.; Timmers, S.; Imhof, R.; Verbeek, J.; Pujol, A.; Loon, B. van; Viscomi, C.; Zeviani, M.; Schrauwen, P.; Sauve, A.A.; Schoonjans, K.; Auwerx, J.

    2014-01-01

    We previously demonstrated that the deletion of the poly(ADP-ribose)polymerase (Parp)-1 gene in mice enhances oxidative metabolism, thereby protecting against diet-induced obesity. However, the therapeutic use of PARP inhibitors to enhance mitochondrial function remains to be explored. Here, we show

  13. [Ubiquinone: metabolism and functions. Ubiquinone deficiency and its implication in mitochondrial encephalopathies. Treatment with ubiquinone].

    Science.gov (United States)

    Artuch, R; Colomé, C; Vilaseca, M A; Pineda, M; Campistol, J

    Review of ubiquinone-10 metabolism and functions in humans, focusing its implication in the pathogenesis and physiopathology of mitochondrial encephalomyopathies. Ubiquinone-10 is an endogenously synthesized lipid with a wide distribution in tissues. Tyrosine and acetil-CoA are involved in ubiquinone biosynthesis. This molecule has several biological functions in cells: it is a movil electron carrier in the mitochondrial respiratory chain and also acts as antioxidant. Owing to its implication in these functions, ubiquinone deficiency may cause important deletereous effects in tissues. Several authors reported ubiquinone deficient status in some physiological and pathological conditions. Mitochondrial encephalomyopathies may be related to a primary or secondary ubiquinone deficient status, or even to an altered function of ubiquinone in the respiratory chain. Moreover, some relevant aspects about ubiquinone therapy in mitochondrial disorders are reported. According to recent reports about ubiquinone implication in several diseases, its determination in different biological samples seems very useful to elucidate the physiopathological mechanisms involved and even the to start a therapy in cases with ubiquinone deficiency.

  14. High fat fed heart failure animals have enhanced mitochondrial function and acyl-coa dehydrogenase activities

    Science.gov (United States)

    We have previously shown that administration of high fat in heart failure (HF) increased mitochondrial respiration and did not alter left ventricular (LV) function. PPARalpha is a nuclear transcription factor that activates expression of genes involved in fatty acid uptake and utilization. We hypoth...

  15. Mitochondrial function in permeabilized cardiomyocytes is largely preserved in the senescent rat myocardium.

    Directory of Open Access Journals (Sweden)

    Martin Picard

    Full Text Available The aging heart is characterized by a progressive decline in contractile function and diastolic relaxation. Amongst the factors implicated in these changes is a progressive replacement fibrosis secondary to cardiomyocyte death, oxidative damage, and energetic deficit, each of which may be secondary to impaired mitochondrial function. Here, we performed an in-depth examination of mitochondrial function in saponin-permeabilized cardiomyocyte bundles, a preparation where all mitochondria are represented and their structure intact, from young adult (YA and senescent (SEN rats (n = 8 per group. When accounting for increased fibrosis (+19%, P<0.01 and proportional decrease in citrate synthase activity in the SEN myocardium (-23%, P<0.05, mitochondrial respiration and reactive oxygen species (H(2O(2 emission across a range of energized states was similar between age groups. Accordingly, the abundance of electron transport chain proteins was also unchanged. Likewise, except for CuZnSOD (-37%, P<0.05, the activity of antioxidant enzymes was unaltered with aging. Although time to mitochondrial permeability transition pore (mPTP opening was decreased (-25%, P<0.05 in the SEN heart, suggesting sensitization to apoptotic stimuli, this was not associated with a difference in apoptotic index measured by ELISA. Collectively, our results suggest that the function of existing cardiac ventricular mitochondria is relatively preserved in SEN rat heart when measured in permeabilized cells.

  16. Integrative functions of the mitochondrial contact site and cristae organizing system.

    Science.gov (United States)

    Schorr, Stefan; van der Laan, Martin

    2018-04-01

    Mitochondria are complex double-membrane-bound organelles of eukaryotic cells that function as energy-converting powerhouses, metabolic factories and signaling centers. The outer membrane controls the exchange of material and information with other cellular compartments. The inner membrane provides an extended, highly folded surface for selective transport and energy-coupling reactions. It can be divided into an inner boundary membrane and tubular or lamellar cristae membranes that accommodate the oxidative phosphorylation units. Outer membrane, inner boundary membrane and cristae come together at crista junctions, where the mitochondrial contact site and cristae organizing system (MICOS) acts as a membrane-shaping and -connecting scaffold. This peculiar architecture is of pivotal importance for multiple mitochondrial functions. Many elaborate studies in the past years have shed light on the subunit composition and organization of MICOS. In this review article, we summarize these insights and then move on to discuss exciting recent discoveries on the integrative functions of MICOS. Multi-faceted connections to other major players of mitochondrial biogenesis and physiology, like the protein import machineries, the oxidative phosphorylation system, carrier proteins and phospholipid biosynthesis enzymes, are currently emerging. Therefore, we propose that MICOS acts as a central hub in mitochondrial membrane architecture and functionality. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Maternal age and in vitro culture affect mitochondrial number and function in equine oocytes and embryos

    NARCIS (Netherlands)

    Hendriks, W Karin; Colleoni, Silvia; Galli, Cesare; Paris, Damien B B P; Colenbrander, Ben; Roelen, Bernard A J; Stout, Tom A E

    2015-01-01

    Advanced maternal age and in vitro embryo production (IVP) predispose to pregnancy loss in horses. We investigated whether mare age and IVP were associated with alterations in mitochondrial (mt) DNA copy number or function that could compromise oocyte and embryo development. Effects of mare age

  18. Brilliant cresyl blue staining negatively affects mitochondrial functions in porcine oocytes.

    Science.gov (United States)

    Santos, E C S; Sato, D; Lucia, T; Iwata, H

    2015-06-01

    The aim of the present study was to examine the effects of brilliant cresyl blue (BCB) staining on mitochondrial functions in porcine oocytes. Cumulus-oocyte complexes (COCs) collected from slaughterhouse-derived porcine ovaries were cultured with (13 μM) or without (0 μM, control) BCB for 60 min. Mitochondrial functions in oocytes were examined immediately after staining or after in vitro maturation. The BCB-stained oocytes produced reactive oxygen species (ROS) at higher levels than control oocytes immediately after staining (2.2-fold, P BCB-treated oocytes than in the control (2.18 versus 2.83 pM and 0.82 versus 1.0, respectively). There was no difference in mitochondrial DNA copy number between the two groups after maturation. The ATP content in early developmental stage embryos (3 days after parthenogenetic activation) was lower in the BCB-stained group than that in the control group but the difference was not significant. In conclusion, BCB staining of oocytes at the immature stage compromises mitochondrial functions throughout oocyte maturation, but function is restored during early embryo development.

  19. Functional genomic analysis of human mitochondrial RNA processing.

    Science.gov (United States)

    Wolf, Ashley R; Mootha, Vamsi K

    2014-05-08

    Both strands of human mtDNA are transcribed in continuous, multigenic units that are cleaved into the mature rRNAs, tRNAs, and mRNAs required for respiratory chain biogenesis. We sought to systematically identify nuclear-encoded proteins that contribute to processing of mtRNAs within the organelle. First, we devised and validated a multiplex MitoString assay that quantitates 27 mature and precursor mtDNA transcripts. Second, we applied MitoString profiling to evaluate the impact of silencing each of 107 mitochondrial-localized, predicted RNA-binding proteins. With the resulting data set, we rediscovered the roles of recently identified RNA-processing enzymes, detected unanticipated roles of known disease genes in RNA processing, and identified new regulatory factors. We demonstrate that one such factor, FASTKD4, modulates the half-lives of a subset of mt-mRNAs and associates with mtRNAs in vivo. MitoString profiling may be useful for diagnosing and deciphering the pathogenesis of mtDNA disorders. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  20. Functional Genomic Analysis of Human Mitochondrial RNA Processing

    Directory of Open Access Journals (Sweden)

    Ashley R. Wolf

    2014-05-01

    Full Text Available Both strands of human mtDNA are transcribed in continuous, multigenic units that are cleaved into the mature rRNAs, tRNAs, and mRNAs required for respiratory chain biogenesis. We sought to systematically identify nuclear-encoded proteins that contribute to processing of mtRNAs within the organelle. First, we devised and validated a multiplex MitoString assay that quantitates 27 mature and precursor mtDNA transcripts. Second, we applied MitoString profiling to evaluate the impact of silencing each of 107 mitochondrial-localized, predicted RNA-binding proteins. With the resulting data set, we rediscovered the roles of recently identified RNA-processing enzymes, detected unanticipated roles of known disease genes in RNA processing, and identified new regulatory factors. We demonstrate that one such factor, FASTKD4, modulates the half-lives of a subset of mt-mRNAs and associates with mtRNAs in vivo. MitoString profiling may be useful for diagnosing and deciphering the pathogenesis of mtDNA disorders.

  1. The role of PGC-1alpha on mitochondrial function and apoptotic susceptibility in muscle

    DEFF Research Database (Denmark)

    Adhihetty, Peter J; Uguccioni, Giulia; Leick, Lotte

    2009-01-01

    Mitochondria are critical for cellular bioenergetics, and they mediate apoptosis within cells. We used whole body peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha) knockout (KO) animals to investigate its role on organelle function, apoptotic signaling, and cytochrome......-c oxidase activity, an indicator of mitochondrial content, in muscle and other tissues (brain, liver, and pancreas). Lack of PGC-1alpha reduced mitochondrial content in all muscles (17-44%; P liver, and pancreas. However, the tissue expression of proteins involved...

  2. Renal Oxidative Stress Induced by Long-Term Hyperuricemia Alters Mitochondrial Function and Maintains Systemic Hypertension

    Directory of Open Access Journals (Sweden)

    Magdalena Cristóbal-García

    2015-01-01

    Full Text Available We addressed if oxidative stress in the renal cortex plays a role in the induction of hypertension and mitochondrial alterations in hyperuricemia. A second objective was to evaluate whether the long-term treatment with the antioxidant Tempol prevents renal oxidative stress, mitochondrial alterations, and systemic hypertension in this model. Long-term (11-12 weeks and short-term (3 weeks effects of oxonic acid induced hyperuricemia were studied in rats (OA, 750 mg/kg BW, OA+Allopurinol (AP, 150 mg/L drinking water, OA+Tempol (T, 15 mg/kg BW, or vehicle. Systolic blood pressure, renal blood flow, and vascular resistance were measured. Tubular damage (urine N-acetyl-β-D-glucosaminidase and oxidative stress markers (lipid and protein oxidation along with ATP levels were determined in kidney tissue. Oxygen consumption, aconitase activity, and uric acid were evaluated in isolated mitochondria from renal cortex. Short-term hyperuricemia resulted in hypertension without demonstrable renal oxidative stress or mitochondrial dysfunction. Long-term hyperuricemia induced hypertension, renal vasoconstriction, tubular damage, renal cortex oxidative stress, and mitochondrial dysfunction and decreased ATP levels. Treatments with Tempol and allopurinol prevented these alterations. Renal oxidative stress induced by hyperuricemia promoted mitochondrial functional disturbances and decreased ATP content, which represent an additional pathogenic mechanism induced by chronic hyperuricemia. Hyperuricemia-related hypertension occurs before these changes are evident.

  3. Structure, function and evolution of the animal mitochondrial replicative DNA helicase.

    Science.gov (United States)

    Kaguni, Laurie S; Oliveira, Marcos T

    2016-01-01

    The mitochondrial replicative DNA helicase is essential for animal mitochondrial DNA (mtDNA) maintenance. Deleterious mutations in the gene that encodes it cause mitochondrial dysfunction manifested in developmental delays, defects and arrest, limited life span, and a number of human pathogenic phenotypes that are recapitulated in animals across taxa. In fact, the replicative mtDNA helicase was discovered with the identification of human disease mutations in its nuclear gene, and based upon its deduced amino acid sequence homology with bacteriophage T7 gene 4 protein (T7 gp4), a bi-functional primase-helicase. Since that time, numerous investigations of its structure, mechanism, and physiological relevance have been reported, and human disease alleles have been modeled in the human, mouse, and Drosophila systems. Here, we review this literature and draw evolutionary comparisons that serve to shed light on its divergent features.

  4. Fast-twitch glycolytic skeletal muscle is predisposed to age-induced impairments in mitochondrial function

    DEFF Research Database (Denmark)

    Jacobs, Robert A; Díaz, Víctor; Soldini, Lavinia

    2013-01-01

    -resolution respirometry and mitochondrial protein expression in soleus, quadricep, and lateral gastrocnemius skeletal muscles, which represent type 1 slow-twitch oxidative muscle (soleus) and type 2 fast-twitch glycolytic muscle (quadricep and gastrocnemius), respectively, in young (10-12 weeks) and mature (74-76 weeks......) mice. Electron transport through mitochondrial complexes I and III increases with age in quadricep and gastrocnemius, which is not observed in soleus. Mitochondrial coupling efficiency during respiration through complex I also deteriorates with age in gastrocnemius and shows a tendency (p = .085......) to worsen in quadricep. These data demonstrate actual alterations in electron transport function that occurs with age and are dependent on skeletal muscle type....

  5. Tetracyclines Disturb Mitochondrial Function across Eukaryotic Models: A Call for Caution in Biomedical Research

    Directory of Open Access Journals (Sweden)

    Norman Moullan

    2015-03-01

    Full Text Available In recent years, tetracyclines, such as doxycycline, have become broadly used to control gene expression by virtue of the Tet-on/Tet-off systems. However, the wide range of direct effects of tetracycline use has not been fully appreciated. We show here that these antibiotics induce a mitonuclear protein imbalance through their effects on mitochondrial translation, an effect that likely reflects the evolutionary relationship between mitochondria and proteobacteria. Even at low concentrations, tetracyclines induce mitochondrial proteotoxic stress, leading to changes in nuclear gene expression and altered mitochondrial dynamics and function in commonly used cell types, as well as worms, flies, mice, and plants. Given that tetracyclines are so widely applied in research, scientists should be aware of their potentially confounding effects on experimental results. Furthermore, these results caution against extensive use of tetracyclines in livestock due to potential downstream impacts on the environment and human health.

  6. Does cognitive function predict frequency compressed speech recognition in listeners with normal hearing and normal cognition?

    Science.gov (United States)

    Ellis, Rachel J; Munro, Kevin J

    2013-01-01

    The aim was to investigate the relationship between cognitive ability and frequency compressed speech recognition in listeners with normal hearing and normal cognition. Speech-in-noise recognition was measured using Institute of Electrical and Electronic Engineers sentences presented over earphones at 65 dB SPL and a range of signal-to-noise ratios. There were three conditions: unprocessed, and at frequency compression ratios of 2:1 and 3:1 (cut-off frequency, 1.6 kHz). Working memory and cognitive ability were measured using the reading span test and the trail making test, respectively. Participants were 15 young normally-hearing adults with normal cognition. There was a statistically significant reduction in mean speech recognition from around 80% when unprocessed to 40% for 2:1 compression and 30% for 3:1 compression. There was a statistically significant relationship between speech recognition and cognition for the unprocessed condition but not for the frequency-compressed conditions. The relationship between cognitive functioning and recognition of frequency compressed speech-in-noise was not statistically significant. The findings may have been different if the participants had been provided with training and/or time to 'acclimatize' to the frequency-compressed conditions.

  7. Normalization.

    Science.gov (United States)

    Cuevas, Eduardo J.

    1997-01-01

    Discusses cornerstone of Montessori theory, normalization, which asserts that if a child is placed in an optimum prepared environment where inner impulses match external opportunities, the undeviated self emerges, a being totally in harmony with its surroundings. Makes distinctions regarding normalization, normalized, and normality, indicating how…

  8. A novel method for determining human ex vivo submaximal skeletal muscle mitochondrial function

    Science.gov (United States)

    Hey-Mogensen, Martin; Gram, Martin; Jensen, Martin Borch; Lund, Michael Taulo; Hansen, Christina Neigaard; Scheibye-Knudsen, Morten; Bohr, Vilhelm A; Dela, Flemming

    2015-01-01

    Abstract Despite numerous studies, there is no consensus about whether mitochondrial function is altered with increased age. The novelty of the present study is the determination of mitochondrial function at submaximal activity rates, which is more physiologically relevant than the ex vivo functionality protocols used previously. Muscle biopsies were taken from 64 old or young male subjects (aged 60–70 or 20–30 years). Aged subjects were recruited as trained or untrained. Muscle biopsies were used for the isolation of mitochondria and subsequent measurements of DNA repair, anti-oxidant capacity and mitochondrial protein levels (complexes I–V). Mitochondrial function was determined by simultaneous measurement of oxygen consumption, membrane potential and hydrogen peroxide emission using pyruvate + malate (PM) or succinate + rotenone (SR) as substrates. Proton leak was lower in aged subjects when determined at the same membrane potential and was unaffected by training status. State 3 respiration was lower in aged untrained subjects. This effect, however, was alleviated in aged trained subjects. H2O2 emission with PM was higher in aged subjects, and was exacerbated by training, although it was not changed when using SR. However, with a higher manganese superoxide dismuthase content, the trained aged subjects may actually have lower or similar mitochondrial superoxide emission compared to the untrained subjects. We conclude that ageing and the physical activity level in aged subjects are both related to changes in the intrinsic functionality of the mitochondrion in skeletal muscle. Both of these changes could be important factors in determining the metabolic health of the aged skeletal muscle cell. Key points The present study utilized a novel method aiming to investigate mitochondrial function in human skeletal muscle at submaximal levels and at a predefined membrane potential. The effect of age and training status was investigated using a cross

  9. Mitochondrial bioenergetics during the initiation of mercuric chloride-induced renal injury. I. Direct effects of in vitro mercuric chloride on renal cortical mitochondrial function

    Energy Technology Data Exchange (ETDEWEB)

    Weinberg, J.M. (Veterans Administration Medical Center, Ann Arbor, MI); Harding, P.G.; Humes, H.D.

    1982-01-01

    Increasing data suggest that mitochondrial dysfunction may be an important early component of nephrotoxin-induced changes in renal cell function and viability. This study was designed to obtain more detailed information about the effects on several basic bioenergetic parameters of the direct interaction of Hg/sup 2 +/ with renal cortical mitochondria in vitro as a necessary prelude to studies of mitochondrial functional changes after treatment with mercuric chloride in vivo. Beginning at a threshhold level of 2 nmol of Hg/sup 2 +//mg of mitochondrial protein Hg/sup 2 +/ induced marked stimulation of State 4 respiration, mild inhibition of State 3 respiration, and 2,4-dinitrophenol uncoupled respiration, a striking increase in atractyloside-insensitive ADP uptake and stimulation of both basal- and Mg/sup 2 +/-activated oligomycin-sensitive mitochondrial ATPase activity. These effects of Hg/sup 2 +/ could be prevented and reversed by the sulfhydryl reagent dithioerythritol and by albumin but were not affected by Mg/sup 2 +/. Detailed studies on the addition of HgCl/sub 2/ to the preparation at different stages of the mitochondrial isolation procedure demonstrated that the presence of other proteins decreased mitochondrial Hg/sup 2 +/ binding, that the Hg/sup 2 +/ was not readily washed off the mitochondria by nonprotein-containing solutions, and that prolonged exposure of mitochondria to Hg/sup 2 +/ during the isolation procedure did not markedly alter its functional effects on their reversibility as assessed on the final mitochondrial preparation. These data provide an important basis for critically assessing the changes in function of mitochondria isolated after in vivo treatment with mercuric chloride.

  10. Mitochondrial function and autophagy: integrating proteotoxic, redox, and metabolic stress in Parkinson's disease.

    Science.gov (United States)

    Zhang, Jianhua; Culp, Matilda Lillian; Craver, Jason G; Darley-Usmar, Victor

    2018-01-17

    Parkinson's disease (PD) is a movement disorder with widespread neurodegeneration in the brain. Significant oxidative, reductive, metabolic, and proteotoxic alterations have been observed in PD postmortem brains. The alterations of mitochondrial function resulting in decreased bioenergetic health is important and needs to be further examined to help develop biomarkers for PD severity and prognosis. It is now becoming clear that multiple hits on metabolic and signaling pathways are likely to exacerbate PD pathogenesis. Indeed, data obtained from genetic and genome association studies have implicated interactive contributions of genes controlling protein quality control and metabolism. For example, loss of key proteins that are responsible for clearance of dysfunctional mitochondria through a process called mitophagy has been found to cause PD, and a significant proportion of genes associated with PD encode proteins involved in the autophagy-lysosomal pathway. In this review, we highlight the evidence for the targeting of mitochondria by proteotoxic, redox and metabolic stress, and the role autophagic surveillance in maintenance of mitochondrial quality. Furthermore, we summarize the role of α-synuclein, leucine-rich repeat kinase 2, and tau in modulating mitochondrial function and autophagy. Among the stressors that can overwhelm the mitochondrial quality control mechanisms, we will discuss 4-hydroxynonenal and nitric oxide. The impact of autophagy is context depend and as such can have both beneficial and detrimental effects. Furthermore, we highlight the potential of targeting mitochondria and autophagic function as an integrated therapeutic strategy and the emerging contribution of the microbiome to PD susceptibility. © 2018 International Society for Neurochemistry.

  11. SIRT1 is required for AMPK activation and the beneficial effects of resveratrol on mitochondrial function

    Science.gov (United States)

    Price, Nathan L.; Gomes, Ana P.; Ling, Alvin J.Y.; Duarte, Filipe V.; Martin-Montalvo, Alejandro; North, Brian J.; Agarwal, Beamon; Ye, Lan; Ramadori, Giorgio; Teodoro, Joao S.; Hubbard, Basil P.; Varela, Ana T.; Davis, James G.; Varamini, Behzad; Hafner, Angela; Moaddel, Ruin; Rolo, Anabela P.; Coppari, Roberto; Palmeira, Carlos M.; de Cabo, Rafael; Baur, Joseph A.; Sinclair, David A.

    2012-01-01

    SUMMARY Resveratrol induces mitochondrial biogenesis and protects against metabolic decline but whether SIRT1 mediates these benefits is the subject of debate. To circumvent the developmental defects of germ-line SIRT1 knockouts, we have developed the first inducible system that permits whole-body deletion of SIRT1 in adult mice. Mice treated with a moderate dose of resveratrol showed increased mitochondrial biogenesis and function, AMPK activation and increased NAD+ levels in skeletal muscle, whereas SIRT1 knockouts displayed none of these benefits. A mouse overexpressing SIRT1 mimicked these effects. A high dose of resveratrol activated AMPK in a SIRT1-independent manner, demonstrating that resveratrol dosage is a critical factor. Importantly, at both doses of resveratrol no improvements in mitochondrial function were observed in animals lacking SIRT1. Together these data indicate that SIRT1 plays an essential role in the ability of moderate doses of resveratrol to stimulate AMPK and improve mitochondrial function both in vitro and in vivo. PMID:22560220

  12. Novel Functional Role of Heat Shock Protein 90 in Mitochondrial Connexin 43-Mediated Hypoxic Postconditioning

    Directory of Open Access Journals (Sweden)

    Rong-Hui Tu

    2017-11-01

    Full Text Available Background/Aims: Previous studies have shown that heat shock protein 90 (HSP90-mediated mitochondrial import of connexin 43 (Cx43 is critical in preconditioning cardioprotection. The present study was designed to test whether postconditioning has the same effect as preconditioning in promoting Cx43 translocation to mitochondria and whether mitochondrial HSP90 modulates this effect. Methods: Cellular models of hypoxic postconditioning (HPC from rat heart-derived H9c2 cells and neonatal rat cardiomyocytes were employed. The effects of HPC on cardiomyocytes apoptosis were examined by flow cytometry and Hoechst 33342 fluorescent staining. Reactive oxidative species (ROS production was assessed with the peroxide-sensitive fluorescent probe 2′,7′-dichlorofluorescin in diacetate (DCFH-DA. The anti- and pro-apoptotic markers Bcl-2 and Bax, HSP90 and Cx43 protein levels were studied by Western blot analysis in total cell homogenate and sarcolemmal and mitochondrial fractions. The effects on HPC of the HSP90 inhibitor geldanamycin (GA, ROS scavengers superoxide dismutase (SOD and catalase (CAT, and small interfering RNA (siRNA targeting Cx43 and HSP90 were also investigated. Results: HPC significantly reduced hypoxia/reoxygenation (H/R-induced cardiomyocyte apoptosis. These beneficial effects were accompanied by an increase in Bcl-2 levels and a decrease in Bax levels in both sarcolemmal and mitochondrial fractions. HPC with siRNA targeting Cx43 or the ROS scavengers SOD plus CAT significantly prevented ROS generation and HPC cardioprotection, but HPC with either SOD or CAT did not. These data strongly supported the involvement of Cx43 in HPC cardioprotection, likely via modulation of the ROS balance which plays a central role in HPC protection. Furthermore, HPC increased total and mitochondrial levels of HSP90 and the mitochondria-to-sarcolemma ratio of Cx43; blocking the function of HSP90 with the HSP90 inhibitor geldanamycin (GA or siRNA targeting

  13. Normal family of meromorphic functions concerning fixed-points

    Science.gov (United States)

    Fang, Caiyun; Xu, Yan

    2017-09-01

    Let A>1 be a constant and F be a family of meromorphic functions defined in a domain D. For each f\\in F , f has only zeros of multiplicity at least 3 and satisfies the following conditions: (1) |f^' ' ' }(z)|≤ A|z| when f(z)=0 ; (2) f^' ' ' }(z)≠ z ; (3) all poles of f are multiple. In this paper, we characterize the non-normal sequences of F.

  14. Normalization of the collage regions of iterated function systems

    Science.gov (United States)

    Zhang, Zhengbing; Zhang, Wei

    2012-11-01

    Fractal graphics, generated with iterated function systems (IFS), have been applied in broad areas. Since the collage regions of different IFS may be different, it is difficult to respectively show the attractors of iterated function systems in a same region on a computer screen using one program without modifying the display parameters. An algorithm is proposed in this paper to solve this problem. A set of transforms are repeatedly applied to modify the coefficients of the IFS so that the collage region of the resulted IFS changes toward the unit square. Experimental results demonstrate that the collage region of any IFS can be normalized to the unit square with the proposed method.

  15. Associations between fatty acid oxidation, hepatic mitochondrial function, and plasma acylcarnitine levels in mice.

    Science.gov (United States)

    Bjørndal, Bodil; Alterås, Eva Katrine; Lindquist, Carine; Svardal, Asbjørn; Skorve, Jon; Berge, Rolf K

    2018-01-01

    The 4-thia fatty acid tetradecylthiopropionic acid (TTP) is known to inhibit mitochondrial β-oxidation, and can be used as chemically induced hepatic steatosis-model in rodents, while 3-thia fatty acid tetradecylthioacetic acid (TTA) stimulates fatty acid oxidation through activation of peroxisome proliferator activated receptor alpha (PPARα). We wished to determine how these two compounds affected in vivo respiration and mitochondrial efficiency, with an additional goal to elucidate whether mitochondrial function is reflected in plasma acylcarnitine levels. C57BL/6 mice were divided in 4 groups of 10 mice and fed a control low-fat diet, low-fat diets with 0.4% ( w /w) TTP, 0.4% TTA or a combination of these two fatty acids for three weeks ( n  = 10). At sacrifice, β-oxidation and oxidative phosphorylation (OXPHOS) capacity was analysed in fresh liver samples. Hepatic mitochondria were studied using transmission electron microscopy. Lipid classes were measured in plasma, heart and liver, acylcarnitines were measured in plasma, and gene expression was measured in liver. The TTP diet resulted in hepatic lipid accumulation, plasma L-carnitine and acetylcarnitine depletion and elevated palmitoylcarnitine and non-esterified fatty acid levels. No significant lipid accumulation was observed in heart. The TTA supplement resulted in enhanced hepatic β-oxidation, accompanied by an increased level of acetylcarnitine and palmitoylcarnitine in plasma. Analysis of mitochondrial respiration showed that TTP reduced oxidative phosphorylation, while TTA increased the maximum respiratory capacity of the electron transport system. Combined treatment with TTP and TTA resulted in a profound stimulation of genes involved in the PPAR-response and L-carnitine metabolism, and partly prevented triacylglycerol accumulation in the liver concomitant with increased peroxisomal β-oxidation and depletion of plasma acetylcarnitines. Despite an increased number of mitochondria in the liver

  16. Modulation of mitochondrial function and morphology by interaction of Omi/HtrA2 with the mitochondrial fusion factor OPA1

    International Nuclear Information System (INIS)

    Kieper, Nicole; Holmstroem, Kira M.; Ciceri, Dalila; Fiesel, Fabienne C.; Wolburg, Hartwig; Ziviani, Elena; Whitworth, Alexander J.; Martins, L. Miguel; Kahle, Philipp J.; Krueger, Rejko

    2010-01-01

    Loss of Omi/HtrA2 function leads to nerve cell loss in mouse models and has been linked to neurodegeneration in Parkinson's and Huntington's disease. Omi/HtrA2 is a serine protease released as a pro-apoptotic factor from the mitochondrial intermembrane space into the cytosol. Under physiological conditions, Omi/HtrA2 is thought to be involved in protection against cellular stress, but the cytological and molecular mechanisms are not clear. Omi/HtrA2 deficiency caused an accumulation of reactive oxygen species and reduced mitochondrial membrane potential. In Omi/HtrA2 knockout mouse embryonic fibroblasts, as well as in Omi/HtrA2 silenced human HeLa cells and Drosophila S2R+ cells, we found elongated mitochondria by live cell imaging. Electron microscopy confirmed the mitochondrial morphology alterations and showed abnormal cristae structure. Examining the levels of proteins involved in mitochondrial fusion, we found a selective up-regulation of more soluble OPA1 protein. Complementation of knockout cells with wild-type Omi/HtrA2 but not with the protease mutant [S306A]Omi/HtrA2 reversed the mitochondrial elongation phenotype and OPA1 alterations. Finally, co-immunoprecipitation showed direct interaction of Omi/HtrA2 with endogenous OPA1. Thus, we show for the first time a direct effect of loss of Omi/HtrA2 on mitochondrial morphology and demonstrate a novel role of this mitochondrial serine protease in the modulation of OPA1. Our results underscore a critical role of impaired mitochondrial dynamics in neurodegenerative disorders.

  17. Modulation of mitochondrial function and morphology by interaction of Omi/HtrA2 with the mitochondrial fusion factor OPA1

    Energy Technology Data Exchange (ETDEWEB)

    Kieper, Nicole; Holmstroem, Kira M.; Ciceri, Dalila; Fiesel, Fabienne C. [Center of Neurology and Hertie Institute for Clinical Brain Research, 72076 Tuebingen (Germany); Wolburg, Hartwig [Institute of Pathology, University of Tuebingen, 72076 Tuebingen (Germany); Ziviani, Elena; Whitworth, Alexander J. [Medical Research Council Centre for Developmental and Biomedical Genetics, University of Sheffield, Sheffield S10 2TN (United Kingdom); Martins, L. Miguel [Cell Death Regulation Laboratory, MRC Toxicology Unit, Leicester LE1 9HN (United Kingdom); Kahle, Philipp J., E-mail: philipp.kahle@uni-tuebingen.de [Center of Neurology and Hertie Institute for Clinical Brain Research, 72076 Tuebingen (Germany); Krueger, Rejko, E-mail: rejko.krueger@uni-tuebingen.de [Center of Neurology and Hertie Institute for Clinical Brain Research, 72076 Tuebingen (Germany)

    2010-04-15

    Loss of Omi/HtrA2 function leads to nerve cell loss in mouse models and has been linked to neurodegeneration in Parkinson's and Huntington's disease. Omi/HtrA2 is a serine protease released as a pro-apoptotic factor from the mitochondrial intermembrane space into the cytosol. Under physiological conditions, Omi/HtrA2 is thought to be involved in protection against cellular stress, but the cytological and molecular mechanisms are not clear. Omi/HtrA2 deficiency caused an accumulation of reactive oxygen species and reduced mitochondrial membrane potential. In Omi/HtrA2 knockout mouse embryonic fibroblasts, as well as in Omi/HtrA2 silenced human HeLa cells and Drosophila S2R+ cells, we found elongated mitochondria by live cell imaging. Electron microscopy confirmed the mitochondrial morphology alterations and showed abnormal cristae structure. Examining the levels of proteins involved in mitochondrial fusion, we found a selective up-regulation of more soluble OPA1 protein. Complementation of knockout cells with wild-type Omi/HtrA2 but not with the protease mutant [S306A]Omi/HtrA2 reversed the mitochondrial elongation phenotype and OPA1 alterations. Finally, co-immunoprecipitation showed direct interaction of Omi/HtrA2 with endogenous OPA1. Thus, we show for the first time a direct effect of loss of Omi/HtrA2 on mitochondrial morphology and demonstrate a novel role of this mitochondrial serine protease in the modulation of OPA1. Our results underscore a critical role of impaired mitochondrial dynamics in neurodegenerative disorders.

  18. Estradiol affects liver mitochondrial function in ovariectomized and tamoxifen-treated ovariectomized female rats

    International Nuclear Information System (INIS)

    Moreira, Paula I.; Custodio, Jose B.A.; Nunes, Elsa; Moreno, Antonio; Seica, Raquel; Oliveira, Catarina R.; Santos, Maria S.

    2007-01-01

    Given the tremendous importance of mitochondria to basic cellular functions as well as the critical role of mitochondrial impairment in a vast number of disorders, a compelling question is whether 17β-estradiol (E2) modulates mitochondrial function. To answer this question we exposed isolated liver mitochondria to E2. Three groups of rat females were used: control, ovariectomized and ovariectomized treated with tamoxifen. Tamoxifen has antiestrogenic effects in the breast tissue and is the standard endocrine treatment for women with breast cancer. However, under certain circumstances and in certain tissues, tamoxifen can also exert estrogenic agonist properties. We observed that at basal conditions, ovariectomy and tamoxifen treatment do not induce any statistical alteration in oxidative phosphorylation system and respiratory chain parameters. Furthermore, tamoxifen treatment increases the capacity of mitochondria to accumulate Ca 2+ delaying the opening of the permeability transition pore. The presence of 25 μM E2 impairs respiration and oxidative phosphorylation system these effects being similar in all groups of animals studied. Curiously, E2 protects against lipid peroxidation and increases the production of H 2 O 2 in energized mitochondria of control females. Our results indicate that E2 has in general deleterious effects that lead to mitochondrial impairment. Since mitochondrial dysfunction is a triggering event of cell degeneration and death, the use of exogenous E2 must be carefully considered

  19. Redox state and mitochondrial respiratory chain function in skeletal muscle of LGMD2A patients.

    Directory of Open Access Journals (Sweden)

    Mats I Nilsson

    Full Text Available Calpain-3 deficiency causes oxidative and nitrosative stress-induced damage in skeletal muscle of LGMD2A patients, but mitochondrial respiratory chain function and anti-oxidant levels have not been systematically assessed in this clinical population previously.We identified 14 patients with phenotypes consistent with LGMD2A and performed CAPN3 gene sequencing, CAPN3 expression/autolysis measurements, and in silico predictions of pathogenicity. Oxidative damage, anti-oxidant capacity, and mitochondrial enzyme activities were determined in a subset of muscle biopsies.Twenty-one disease-causing variants were detected along the entire CAPN3 gene, five of which were novel (c.338 T>C, c.500 T>C, c.1525-1 G>T, c.2115+4 T>G, c.2366 T>A. Protein- and mRNA-based tests confirmed in silico predictions and the clinical diagnosis in 75% of patients. Reductions in antioxidant defense mechanisms (SOD-1 and NRF-2, but not SOD-2, coupled with increased lipid peroxidation and protein ubiquitination, were observed in calpain-3 deficient muscle, indicating a redox imbalance primarily affecting non-mitochondrial compartments. Although ATP synthase levels were significantly lower in LGMD2A patients, citrate synthase, cytochrome c oxidase, and complex I+III activities were not different from controls.Despite significant oxidative damage and redox imbalance in cytosolic/myofibrillar compartments, mitochondrial respiratory chain function is largely maintained in skeletal muscle of LGMD2A patients.

  20. Titanium Dioxide Nanoparticles Trigger Loss of Function and Perturbation of Mitochondrial Dynamics in Primary Hepatocytes.

    Directory of Open Access Journals (Sweden)

    Vaishaali Natarajan

    Full Text Available Titanium dioxide (TiO2 nanoparticles are one of the most highly manufactured and employed nanomaterials in the world with applications in copious industrial and consumer products. The liver is a major accumulation site for many nanoparticles, including TiO2, directly through intentional exposure or indirectly through unintentional ingestion via water, food or animals and increased environmental contamination. Growing concerns over the current usage of TiO2 coupled with the lack of mechanistic understanding of its potential health risk is the motivation for this study. Here we determined the toxic effect of three different TiO2 nanoparticles (commercially available rutile, anatase and P25 on primary rat hepatocytes. Specifically, we evaluated events related to hepatocyte functions and mitochondrial dynamics: (1 urea and albumin synthesis using colorimetric and ELISA assays, respectively; (2 redox signaling mechanisms by measuring reactive oxygen species (ROS production, manganese superoxide dismutase (MnSOD activity and mitochondrial membrane potential (MMP; (3 OPA1 and Mfn-1 expression that mediates the mitochondrial dynamics by PCR; and (4 mitochondrial morphology by MitoTracker Green FM staining. All three TiO2 nanoparticles induced a significant loss (p < 0.05 in hepatocyte functions even at concentrations as low as 50 ppm with commercially used P25 causing maximum damage. TiO2 nanoparticles induced a strong oxidative stress in primary hepatocytes. TiO2 nanoparticles exposure also resulted in morphological changes in mitochondria and substantial loss in the fusion process, thus impairing the mitochondrial dynamics. Although this study demonstrated that TiO2 nanoparticles exposure resulted in substantial damage to primary hepatocytes, more in vitro and in vivo studies are required to determine the complete toxicological mechanism in primary hepatocytes and subsequently liver function.

  1. Oxidative stress and mitochondrial function : Role of ubiquinol as antioxidant

    OpenAIRE

    Andrée, Patrik

    1996-01-01

    Doctoral Dissertation 1996 Clinical Research Center Division of Medical Cell Biology Karolinska Institutet, NOVUM S-141 86 Huddinge, Sweden Over the last three decades it has been established that biquinone (coenzyme Q), in addition to its function as an electron and proton carrier in the respiratory chain, acts in its reduced form (ubiquinol) as an antioxidant. The main theme of this thesis is a study of the antioxidant function of ubiquinol in prepara...

  2. Enhanced Neuroplasticity by the Metabolic Enhancer Piracetam Associated with Improved Mitochondrial Dynamics and Altered Permeability Transition Pore Function

    Directory of Open Access Journals (Sweden)

    Carola Stockburger

    2016-01-01

    Full Text Available The mitochondrial cascade hypothesis of dementia assumes mitochondrial dysfunction leading to reduced energy supply, impaired neuroplasticity, and finally cell death as one major pathomechanism underlying the continuum from brain aging over mild cognitive impairment to initial and advanced late onset Alzheimer’s disease. Accordingly, improving mitochondrial function has become an important strategy to treat the early stages of this continuum. The metabolic enhancer piracetam has been proposed as possible prototype for those compounds by increasing impaired mitochondrial function and related aspects like mechanisms of neuroplasticity. We here report that piracetam at therapeutically relevant concentrations improves neuritogenesis in the human cell line SH-SY5Y over conditions mirroring the whole spectrum of age-associated cognitive decline. These effects go parallel with improvement of impaired mitochondrial dynamics shifting back fission and fusion balance to the energetically more favorable fusion site. Impaired fission and fusion balance can also be induced by a reduction of the mitochondrial permeability transition pore (mPTP function as atractyloside which indicates the mPTP has similar effects on mitochondrial dynamics. These changes are also reduced by piracetam. These findings suggest the mPTP as an important target for the beneficial effects of piracetam on mitochondrial function.

  3. Enhanced Neuroplasticity by the Metabolic Enhancer Piracetam Associated with Improved Mitochondrial Dynamics and Altered Permeability Transition Pore Function.

    Science.gov (United States)

    Stockburger, Carola; Miano, Davide; Pallas, Thea; Friedland, Kristina; Müller, Walter E

    2016-01-01

    The mitochondrial cascade hypothesis of dementia assumes mitochondrial dysfunction leading to reduced energy supply, impaired neuroplasticity, and finally cell death as one major pathomechanism underlying the continuum from brain aging over mild cognitive impairment to initial and advanced late onset Alzheimer's disease. Accordingly, improving mitochondrial function has become an important strategy to treat the early stages of this continuum. The metabolic enhancer piracetam has been proposed as possible prototype for those compounds by increasing impaired mitochondrial function and related aspects like mechanisms of neuroplasticity. We here report that piracetam at therapeutically relevant concentrations improves neuritogenesis in the human cell line SH-SY5Y over conditions mirroring the whole spectrum of age-associated cognitive decline. These effects go parallel with improvement of impaired mitochondrial dynamics shifting back fission and fusion balance to the energetically more favorable fusion site. Impaired fission and fusion balance can also be induced by a reduction of the mitochondrial permeability transition pore (mPTP) function as atractyloside which indicates the mPTP has similar effects on mitochondrial dynamics. These changes are also reduced by piracetam. These findings suggest the mPTP as an important target for the beneficial effects of piracetam on mitochondrial function.

  4. Sex differences in normal age trajectories of functional brain networks.

    Science.gov (United States)

    Scheinost, Dustin; Finn, Emily S; Tokoglu, Fuyuze; Shen, Xilin; Papademetris, Xenophon; Hampson, Michelle; Constable, R Todd

    2015-04-01

    Resting-state functional magnetic resonance image (rs-fMRI) is increasingly used to study functional brain networks. Nevertheless, variability in these networks due to factors such as sex and aging is not fully understood. This study explored sex differences in normal age trajectories of resting-state networks (RSNs) using a novel voxel-wise measure of functional connectivity, the intrinsic connectivity distribution (ICD). Males and females showed differential patterns of changing connectivity in large-scale RSNs during normal aging from early adulthood to late middle-age. In some networks, such as the default-mode network, males and females both showed decreases in connectivity with age, albeit at different rates. In other networks, such as the fronto-parietal network, males and females showed divergent connectivity trajectories with age. Main effects of sex and age were found in many of the same regions showing sex-related differences in aging. Finally, these sex differences in aging trajectories were robust to choice of preprocessing strategy, such as global signal regression. Our findings resolve some discrepancies in the literature, especially with respect to the trajectory of connectivity in the default mode, which can be explained by our observed interactions between sex and aging. Overall, results indicate that RSNs show different aging trajectories for males and females. Characterizing effects of sex and age on RSNs are critical first steps in understanding the functional organization of the human brain. © 2014 Wiley Periodicals, Inc.

  5. Functions of autophagy in normal and diseased liver

    Science.gov (United States)

    Czaja, Mark J.; Ding, Wen-Xing; Donohue, Terrence M.; Friedman, Scott L.; Kim, Jae-Sung; Komatsu, Masaaki; Lemasters, John J.; Lemoine, Antoinette; Lin, Jiandie D.; Ou, Jing-hsiung James; Perlmutter, David H.; Randall, Glenn; Ray, Ratna B.; Tsung, Allan; Yin, Xiao-Ming

    2013-01-01

    Autophagy has emerged as a critical lysosomal pathway that maintains cell function and survival through the degradation of cellular components such as organelles and proteins. Investigations specifically employing the liver or hepatocytes as experimental models have contributed significantly to our current knowledge of autophagic regulation and function. The diverse cellular functions of autophagy, along with unique features of the liver and its principal cell type the hepatocyte, suggest that the liver is highly dependent on autophagy for both normal function and to prevent the development of disease states. However, instances have also been identified in which autophagy promotes pathological changes such as the development of hepatic fibrosis. Considerable evidence has accumulated that alterations in autophagy are an underlying mechanism of a number of common hepatic diseases including toxin-, drug- and ischemia/reperfusion-induced liver injury, fatty liver, viral hepatitis and hepatocellular carcinoma. This review summarizes recent advances in understanding the roles that autophagy plays in normal hepatic physiology and pathophysiology with the intent of furthering the development of autophagy-based therapies for human liver diseases. PMID:23774882

  6. Beneficial effects of a Q-ter based nutritional mixture on functional performance, mitochondrial function, and oxidative stress in rats.

    Science.gov (United States)

    Xu, Jinze; Seo, Arnold Y; Vorobyeva, Darya A; Carter, Christy S; Anton, Stephen D; Lezza, Angela M S; Leeuwenburgh, Christiaan

    2010-05-11

    Mitochondrial dysfunction and oxidative stress are central mechanisms underlying the aging process and the pathogenesis of many age-related diseases. Selected antioxidants and specific combinations of nutritional compounds could target many biochemical pathways that affect both oxidative stress and mitochondrial function and, thereby, preserve or enhance physical performance. In this study, we evaluated the potential anti-aging benefits of a Q-ter based nutritional mixture (commercially known as Eufortyn) mainly containing the following compounds: terclatrated coenzyme Q(10) (Q-ter), creatine and a standardized ginseng extract. We found that Eufortyn supplementation significantly ameliorated the age-associated decreases in grip strength and gastrocnemius subsarcolemmal mitochondria Ca(2+) retention capacity when initiated in male Fischer344 x Brown Norway rats at 21 months, but not 29 months, of age. Moreover, the increases in muscle RNA oxidation and subsarcolemmal mitochondrial protein carbonyl levels, as well as the decline of total urine antioxidant power, which develop late in life, were mitigated by Eufortyn supplementation in rats at 29 months of age. These data imply that Eufortyn is efficacious in reducing oxidative damage, improving the age-related mitochondrial functional decline, and preserving physical performance when initiated in animals at early midlife (21 months). The efficacy varied, however, according to the age at which the supplementation was provided, as initiation in late middle age (29 months) was incapable of restoring grip strength and mitochondrial function. Therefore, the Eufortyn supplementation may be particularly beneficial when initiated prior to major biological and functional declines that appear to occur with advancing age.

  7. Beneficial effects of a Q-ter based nutritional mixture on functional performance, mitochondrial function, and oxidative stress in rats.

    Directory of Open Access Journals (Sweden)

    Jinze Xu

    2010-05-01

    Full Text Available Mitochondrial dysfunction and oxidative stress are central mechanisms underlying the aging process and the pathogenesis of many age-related diseases. Selected antioxidants and specific combinations of nutritional compounds could target many biochemical pathways that affect both oxidative stress and mitochondrial function and, thereby, preserve or enhance physical performance.In this study, we evaluated the potential anti-aging benefits of a Q-ter based nutritional mixture (commercially known as Eufortyn mainly containing the following compounds: terclatrated coenzyme Q(10 (Q-ter, creatine and a standardized ginseng extract. We found that Eufortyn supplementation significantly ameliorated the age-associated decreases in grip strength and gastrocnemius subsarcolemmal mitochondria Ca(2+ retention capacity when initiated in male Fischer344 x Brown Norway rats at 21 months, but not 29 months, of age. Moreover, the increases in muscle RNA oxidation and subsarcolemmal mitochondrial protein carbonyl levels, as well as the decline of total urine antioxidant power, which develop late in life, were mitigated by Eufortyn supplementation in rats at 29 months of age.These data imply that Eufortyn is efficacious in reducing oxidative damage, improving the age-related mitochondrial functional decline, and preserving physical performance when initiated in animals at early midlife (21 months. The efficacy varied, however, according to the age at which the supplementation was provided, as initiation in late middle age (29 months was incapable of restoring grip strength and mitochondrial function. Therefore, the Eufortyn supplementation may be particularly beneficial when initiated prior to major biological and functional declines that appear to occur with advancing age.

  8. Pilot study on executive function and adaptive skills in adolescents and young adults with mitochondrial disease.

    Science.gov (United States)

    Schreiber, Hope

    2012-12-01

    High-functioning adolescents and young adults with mitochondrial disease are now attempting transitions to postsecondary environments. This pilot and case study explores factors that interfere with their successful transition through behavior-rating scales addressing academic skills and behavior. In the Behavior Assessment System for Children, Second Edition, Spearman correlation matrices showed that students' attitude to school was associated with depression and anxiety. Mothers' reports linked internalizing disorders with somatic symptoms. Two case studies, with Behavior Rating Inventory of Executive Function profiles, show the role executive functions play in academic success. Attention to both cognitive and psychiatric concerns may increase success in academics and enhance the sense of well-being in older students with mitochondrial disease.

  9. Mitochondrial electron transport chain functions in long-lived Ames dwarf mice

    Science.gov (United States)

    Choksi, Kashyap B.; Nuss, Jonathan E.; DeFord, James H.; Papaconstantinou, John

    2011-01-01

    The age-associated decline in tissue function has been attributed to ROS-mediated oxidative damage due to mitochondrial dysfunction. The long-lived Ames dwarf mouse exhibits resistance to oxidative stress, a physiological characteristic of longevity. It is not known, however, whether there are differences in the electron transport chain (ETC) functions in Ames tissues that are associated with their longevity. In these studies we analyzed enzyme activities of ETC complexes, CI-CV and the coupled CI-CII and CII-CIII activities of mitochondria from several tissues of young, middle aged and old Ames dwarf mice and their corresponding wild type controls to identify potential mitochondrial prolongevity functions. Our studies indicate that post-mitotic heart and skeletal muscle from Ames and wild-type mice show similar changes in ETC complex activities with aging, with the exception of complex IV. Furthermore, the kidney, a slowly proliferating tissue, shows dramatic differences in ETC functions unique to the Ames mice. Our data show that there are tissue specific mitochondrial functions that are characteristic of certain tissues of the long-lived Ames mouse. We propose that this may be a factor in the determination of extended lifespan of dwarf mice. PMID:21934186

  10. Resistance Training with Co-ingestion of Anti-inflammatory Drugs Attenuates Mitochondrial Function

    Directory of Open Access Journals (Sweden)

    Daniele A. Cardinale

    2017-12-01

    Full Text Available Aim: The current study aimed to examine the effects of resistance exercise with concomitant consumption of high vs. low daily doses of non-steroidal anti-inflammatory drugs (NSAIDs on mitochondrial oxidative phosphorylation in skeletal muscle. As a secondary aim, we compared the effects of eccentric overload with conventional training.Methods: Twenty participants were randomized to either a group taking high doses (3 × 400 mg/day of ibuprofen (IBU; 27 ± 5 year; n = 11 or a group ingesting a low dose (1 × 75 mg/day of acetylsalicylic acid (ASA; 26 ± 4 year; n = 9 during 8 weeks of supervised knee extensor resistance training. Each of the subject's legs were randomized to complete the training program using either a flywheel (FW device emphasizing eccentric overload, or a traditional weight stack machine (WS. Maximal mitochondrial oxidative phosphorylation (CI+IIP from permeabilized skeletal muscle bundles was assessed using high-resolution respirometry. Citrate synthase (CS activity was assessed using spectrophotometric techniques and mitochondrial protein content using western blotting.Results: After training, CI+IIP decreased (P < 0.05 in both IBU (23% and ASA (29% with no difference across medical treatments. Although CI+IIP decreased in both legs, the decrease was greater (interaction p = 0.015 in WS (33%, p = 0.001 compared with FW (19%, p = 0.078. CS activity increased (p = 0.027 with resistance training, with no interactions with medical treatment or training modality. Protein expression of ULK1 increased with training in both groups (p < 0.001. The increase in quadriceps muscle volume was not correlated with changes in CI+IIP (R = 0.16.Conclusion: These results suggest that 8 weeks of resistance training with co-ingestion of anti-inflammatory drugs reduces mitochondrial function but increases mitochondrial content. The observed changes were not affected by higher doses of NSAIDs consumption, suggesting that the resistance training

  11. Butyrate Regulates Liver Mitochondrial Function, Efficiency, and Dynamics in Insulin-Resistant Obese Mice.

    Science.gov (United States)

    Mollica, Maria Pina; Mattace Raso, Giuseppina; Cavaliere, Gina; Trinchese, Giovanna; De Filippo, Chiara; Aceto, Serena; Prisco, Marina; Pirozzi, Claudio; Di Guida, Francesca; Lama, Adriano; Crispino, Marianna; Tronino, Diana; Di Vaio, Paola; Berni Canani, Roberto; Calignano, Antonio; Meli, Rosaria

    2017-05-01

    Fatty liver, oxidative stress, and mitochondrial dysfunction are key pathophysiological features of insulin resistance and obesity. Butyrate, produced by fermentation in the large intestine by gut microbiota, and its synthetic derivative, the N-(1-carbamoyl-2-phenyl-ethyl) butyramide, FBA, have been demonstrated to be protective against insulin resistance and fatty liver. Here, hepatic mitochondria were identified as the main target of the beneficial effect of both butyrate-based compounds in reverting insulin resistance and fat accumulation in diet-induced obese mice. In particular, butyrate and FBA improved respiratory capacity and fatty acid oxidation, activated the AMPK-acetyl-CoA carboxylase pathway, and promoted inefficient metabolism, as shown by the increase in proton leak. Both treatments consistently increased utilization of substrates, especially fatty acids, leading to the reduction of intracellular lipid accumulation and oxidative stress. Finally, the shift of the mitochondrial dynamic toward fusion by butyrate and FBA resulted in the improvement not only of mitochondrial cell energy metabolism but also of glucose homeostasis. In conclusion, butyrate and its more palatable synthetic derivative, FBA, modulating mitochondrial function, efficiency, and dynamics, can be considered a new therapeutic strategy to counteract obesity and insulin resistance. © 2017 by the American Diabetes Association.

  12. Putative Structural and Functional Coupling of the Mitochondrial BKCa Channel to the Respiratory Chain.

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    Piotr Bednarczyk

    Full Text Available Potassium channels have been found in the inner mitochondrial membranes of various cells. These channels regulate the mitochondrial membrane potential, the matrix volume and respiration. The activation of these channels is cytoprotective. In our study, the single-channel activity of a large-conductance Ca(2+-regulated potassium channel (mitoBKCa channel was measured by patch-clamping mitoplasts isolated from the human astrocytoma (glioblastoma U-87 MG cell line. A potassium-selective current was recorded with a mean conductance of 290 pS in symmetrical 150 mM KCl solution. The channel was activated by Ca(2+ at micromolar concentrations and by the potassium channel opener NS1619. The channel was inhibited by paxilline and iberiotoxin, known inhibitors of BKCa channels. Western blot analysis, immuno-gold electron microscopy, high-resolution immunofluorescence assays and polymerase chain reaction demonstrated the presence of the BKCa channel β4 subunit in the inner mitochondrial membrane of the human astrocytoma cells. We showed that substrates of the respiratory chain, such as NADH, succinate, and glutamate/malate, decrease the activity of the channel at positive voltages. This effect was abolished by rotenone, antimycin and cyanide, inhibitors of the respiratory chain. The putative interaction of the β4 subunit of mitoBKCa with cytochrome c oxidase was demonstrated using blue native electrophoresis. Our findings indicate possible structural and functional coupling of the mitoBKCa channel with the mitochondrial respiratory chain in human astrocytoma U-87 MG cells.

  13. β-Hydroxybutyrate improves β-cell mitochondrial function and survival

    Directory of Open Access Journals (Sweden)

    MaryJane Sampson

    2017-08-01

    Full Text Available Pharmacological interventions aimed at improving outcomes in type 2 diabetes and achieving normoglycaemia, including insulin therapy, are increasingly common, despite the potential for substantial side effects. Carbohydrate-restricted diets that result in increased ketogenesis have effectively been used to improve insulin resistance, a fundamental feature of type 2 diabetes. In addition, limited evidence suggests that states of ketogenesis may also improve β-cell function in type 2 diabetics. Considering how little is known regarding the effects of ketones on β-cell function, we sought to determine the specific effects of β-Hydroxybutyrate (βHB on pancreatic β-cell physiology and mitochondrial function. βHB treatment increased β-cell survival and proliferation, while also increasing mitochondrial mass, respiration and adenosine triphosphate (ATP production. Despite these improvements, were unable to detect an increase in β-cell or islet insulin production and secretion. Collectively, these findings have two implications. Firstly, they indicate that β-cells have improved survival and proliferation in the midst of βHB, the circulating form of ketones. Secondly, insulin secretion does not appear to be directly related to apparent improvements in mitochondrial function and cellular proliferation.

  14. Loss of mitochondrial exo/endonuclease EXOG affects mitochondrial respiration and induces ROS-mediated cardiomyocyte hypertrophy.

    Science.gov (United States)

    Tigchelaar, Wardit; Yu, Hongjuan; de Jong, Anne Margreet; van Gilst, Wiek H; van der Harst, Pim; Westenbrink, B Daan; de Boer, Rudolf A; Silljé, Herman H W

    2015-01-15

    Recently, a locus at the mitochondrial exo/endonuclease EXOG gene, which has been implicated in mitochondrial DNA repair, was associated with cardiac function. The function of EXOG in cardiomyocytes is still elusive. Here we investigated the role of EXOG in mitochondrial function and hypertrophy in cardiomyocytes. Depletion of EXOG in primary neonatal rat ventricular cardiomyocytes (NRVCs) induced a marked increase in cardiomyocyte hypertrophy. Depletion of EXOG, however, did not result in loss of mitochondrial DNA integrity. Although EXOG depletion did not induce fetal gene expression and common hypertrophy pathways were not activated, a clear increase in ribosomal S6 phosphorylation was observed, which readily explains increased protein synthesis. With the use of a Seahorse flux analyzer, it was shown that the mitochondrial oxidative consumption rate (OCR) was increased 2.4-fold in EXOG-depleted NRVCs. Moreover, ATP-linked OCR was 5.2-fold higher. This increase was not explained by mitochondrial biogenesis or alterations in mitochondrial membrane potential. Western blotting confirmed normal levels of the oxidative phosphorylation (OXPHOS) complexes. The increased OCR was accompanied by a 5.4-fold increase in mitochondrial ROS levels. These increased ROS levels could be normalized with specific mitochondrial ROS scavengers (MitoTEMPO, mnSOD). Remarkably, scavenging of excess ROS strongly attenuated the hypertrophic response. In conclusion, loss of EXOG affects normal mitochondrial function resulting in increased mitochondrial respiration, excess ROS production, and cardiomyocyte hypertrophy. Copyright © 2015 the American Physiological Society.

  15. New insight into the mechanism of mitochondrial cytochrome c function

    DEFF Research Database (Denmark)

    Chertkova, Rita V; Brazhe, Nadezda A; Bryantseva, Tatiana V

    2017-01-01

    We investigate functional role of the P76GTKMIFA83 fragment of the primary structure of cytochrome c. Based on the data obtained by the analysis of informational structure (ANIS), we propose a model of functioning of cytochrome c. According to this model, conformational rearrangements of the P76......GTKMIFA83 loop fragment have a significant effect on conformational mobility of the heme. It is suggested that the conformational mobility of cytochrome c heme is responsible for its optimal orientation with respect to electron donor and acceptor within ubiquinol-cytochrome c oxidoreductase (complex III......) and cytochrome c oxidase (complex IV), respectively, thus, ensuring electron transfer from complex III to complex IV. To validate the model, we design several mutant variants of horse cytochrome c with multiple substitutions of amino acid residues in the P76GTKMIFA83 sequence that reduce its ability to undergo...

  16. Pearson marrow-pancreas syndrome with worsening cardiac function caused by pleiotropic rearrangement of mitochondrial DNA.

    Science.gov (United States)

    Krauch, Gabriele; Wilichowski, Ekkehard; Schmidt, Klaus G; Mayatepek, Ertan

    2002-06-01

    Pearson marrow-pancreas syndrome is a usually fatal disorder that involves the hematopoietic system, exocrine pancreas, liver, kidneys, and often presents clinically with failure to thrive. We report a 5-year-old patient who developed, in addition to the typical features of Pearson syndrome, worsening cardiac function, mainly affecting the left ventricle. The latter finding is particularly interesting because cardiac involvement has not yet been regarded as a major feature of Pearson syndrome. The diagnosis was proved by the finding of so far undescribed pleioplasmatic rearrangement of mitochondrial (mt)DNA (loss of 5,630 bp, 70% deleted and duplicated mtDNA) in blood cells. Our report demonstrates that patients with Pearson syndrome may also have impaired cardiac function. Thus, Pearson syndrome should be considered in the differential diagnosis of patients with left ventricular dysfunction of unknown origin and other clinical findings suggestive of a mitochondrial disease. Copyright 2002 Wiley-Liss, Inc.

  17. Mitochondrial-Targeted Antioxidant Maintains Blood Flow, Mitochondrial Function, and Redox Balance in Old Mice Following Prolonged Limb Ischemia

    Directory of Open Access Journals (Sweden)

    Shunsuke Miura

    2017-09-01

    Full Text Available Aging is a major factor in the decline of limb blood flow with ischemia. However, the underlying mechanism remains unclear. We investigated the role of mitochondrial reactive oxygen species (ROS with regard to limb perfusion recovery in aging during ischemia. We performed femoral artery ligation in young and old mice with or without treatment with a scavenger of mitochondrial superoxide, MitoTEMPO (180 μg/kg/day, from pre-operative day 7 to post-operative day (POD 21 infusion using an implanted mini-pump. The recoveries of cutaneous blood flow in the ischemic hind limb were lower in old mice than in young mice but were improved in MitoTEMPO-treated old mice. Mitochondrial DNA damage appeared in ischemic aged muscles but was eliminated by MitoTEMPO treatment. For POD 2, MitoTEMPO treatment suppressed the expression of p53 and the ratio of Bax/Bcl2 and upregulated the expression of hypoxia-inducible factor-1α (HIF-1α and vascular endothelial growth factor (VEGF in ischemic aged skeletal muscles. For POD 21, MitoTEMPO treatment preserved the expression of PGC-1α in ischemic aged skeletal muscle. The ischemic soleus of old mice showed a lower mitochondrial respiratory control ratio in POD 21 compared to young mice, which was recovered in MitoTEMPO-treated old mice. Scavenging of mitochondrial superoxide attenuated mitochondrial DNA damage and preserved the mitochondrial respiration, in addition to suppression of the expression of p53 and preservation of the expression of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α in ischemic skeletal muscles with aging. Resolution of excessive mitochondrial superoxide could be an effective therapy to recover blood flow of skeletal muscle during ischemia in senescence.

  18. New insight into the mechanism of mitochondrial cytochrome c function.

    Directory of Open Access Journals (Sweden)

    Rita V Chertkova

    Full Text Available We investigate functional role of the P76GTKMIFA83 fragment of the primary structure of cytochrome c. Based on the data obtained by the analysis of informational structure (ANIS, we propose a model of functioning of cytochrome c. According to this model, conformational rearrangements of the P76GTKMIFA83 loop fragment have a significant effect on conformational mobility of the heme. It is suggested that the conformational mobility of cytochrome c heme is responsible for its optimal orientation with respect to electron donor and acceptor within ubiquinol-cytochrome c oxidoreductase (complex III and cytochrome c oxidase (complex IV, respectively, thus, ensuring electron transfer from complex III to complex IV. To validate the model, we design several mutant variants of horse cytochrome c with multiple substitutions of amino acid residues in the P76GTKMIFA83 sequence that reduce its ability to undergo conformational rearrangements. With this, we study the succinate-cytochrome c reductase and cytochrome c oxidase activities of rat liver mitoplasts in the presence of mutant variants of cytochrome c. The electron transport activity of the mutant variants decreases to different extent. Resonance Raman spectroscopy (RRS and surface-enhanced Raman spectroscopy (SERS data demonstrate, that all mutant cytochromes possess heme with the higher degree of ruffling deformation, than that of the wild-type (WT cytochrome c. The increase in the ruffled deformation of the heme of oxidized cytochromes correlated with the decrease in the electron transport rate of ubiquinol-cytochrome c reductase (complex III. Besides, all mutant cytochromes have lower mobility of the pyrrol rings and methine bridges, than WT cytochrome c. We show that a decrease in electron transport activity in the mutant variants correlates with conformational changes and reduced mobility of heme porphyrin. This points to a significant role of the P76GTKMIFA83 fragment in the electron transport

  19. Stomatin-like protein 2 is required for in vivo mitochondrial respiratory chain supercomplex formation and optimal cell function.

    Science.gov (United States)

    Mitsopoulos, Panagiotis; Chang, Yu-Han; Wai, Timothy; König, Tim; Dunn, Stanley D; Langer, Thomas; Madrenas, Joaquín

    2015-05-01

    Stomatin-like protein 2 (SLP-2) is a mainly mitochondrial protein that is widely expressed and is highly conserved across evolution. We have previously shown that SLP-2 binds the mitochondrial lipid cardiolipin and interacts with prohibitin-1 and -2 to form specialized membrane microdomains in the mitochondrial inner membrane, which are associated with optimal mitochondrial respiration. To determine how SLP-2 functions, we performed bioenergetic analysis of primary T cells from T cell-selective Slp-2 knockout mice under conditions that forced energy production to come almost exclusively from oxidative phosphorylation. These cells had a phenotype characterized by increased uncoupled mitochondrial respiration and decreased mitochondrial membrane potential. Since formation of mitochondrial respiratory chain supercomplexes (RCS) may correlate with more efficient electron transfer during oxidative phosphorylation, we hypothesized that the defect in mitochondrial respiration in SLP-2-deficient T cells was due to deficient RCS formation. We found that in the absence of SLP-2, T cells had decreased levels and activities of complex I-III2 and I-III2-IV(1-3) RCS but no defects in assembly of individual respiratory complexes. Impaired RCS formation in SLP-2-deficient T cells correlated with significantly delayed T cell proliferation in response to activation under conditions of limiting glycolysis. Altogether, our findings identify SLP-2 as a key regulator of the formation of RCS in vivo and show that these supercomplexes are required for optimal cell function. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  20. Implication of SPARC in the modulation of the extracellular matrix and mitochondrial function in muscle cells.

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    Aicha Melouane

    Full Text Available Secreted protein, acidic and rich in cysteine (SPARC is differentially associated with cell proliferation and extracellular matrix (ECM assembly. We show here the effect of exogenous SPARC inhibition/induction on ECM and mitochondrial proteins expression and on the differentiation of C2C12 cells. The cells were cultured in growth medium (GM supplemented with different experimental conditions. The differentiation of myoblasts was studied for 5 days, the expressions of ECM and mitochondrial proteins were measured and the formation of the myotubes was quantified after exogenous induction/inhibition of SPARC. The results indicate that the addition of recombinant SPARC protein (rSPARC in cell culture medium increased the differentiation of C2C12 myoblasts and myogenin expression during the myotube formation. However, the treatment with antibody specific for SPARC (anti-SPARC prevented the differentiation and decreased myogenin expression. The induction of SPARC in the proliferating and differentiating C2C12 cells increased collagen 1a1 protein expression, whereas the inhibition decreased it. The effects on fibronectin protein expression were opposite. Furthermore, the addition of rSPARC in C2C12 myoblast increased the expression of mitochondrial proteins, ubiquinol-cytochrome c reductase core protein II (UQCRC2 and succinate dehydrogenase iron-sulfur subunit (SDHB, whereas the anti-SPARC decreased them. During the differentiation, only the anti-SPARC had the effects on mitochondrial proteins, NADH dehydrogenase ubiquinone 1 beta subcomplex subunit 8 (NADHB8, SDHB and cytochrome c oxidase 1 (MTCO1. Thus, SPARC plays a crucial role in the proliferation and differentiation of C2C12 and may be involved in the link between the ECM remodeling and mitochondrial function.

  1. Apolipoprotein O expression in mouse liver enhances hepatic lipid accumulation by impairing mitochondrial function.

    Science.gov (United States)

    Tian, Feng; Wu, Chen-Lu; Yu, Bi-Lian; Liu, Ling; Hu, Jia-Rui

    2017-09-09

    Apolipoprotein O (ApoO) was recently observed in the cellular mitochondrial inner membrane, which plays a role in mitochondrial function and is associated with myocardiopathy. Empirical information on the physiological functions of apoO is therefore limited. In this study, we aimed to elucidate the effect of apoO on hepatic fatty acid metabolism. An adenoviral vector expressing hApoO was constructed and introduced into chow diet and high-fat diet induced mice and the L02 human hepatoma cell line. High levels of hApoO mRNA and protein were detected in the liver, and the expression of lipid metabolism genes was significantly altered compared with negative controls. The liver function indices (serum ALT and AST) were clearly elevated, and the ultrastructure of cellular mitochondria was distinctly altered in the liver after apoO overexpression. Further, mitochondrial membrane potential decreased with hApoO treatment in L02 cells. These results establish a link between apoO and lipid accumulation and could suggest a new pathway for regulating non-alcoholic fatty liver disease progression. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. [Infection of Mice with Normal Immune Function by Taenia asiatica].

    Science.gov (United States)

    Liu, Xiao-yan; Guo, Guang-wu; Chen, Li-hong; Mo, Xing-ze; Yu, Yue-sheng

    2015-08-01

    The Taenia asiatica eggs pre-incubated with sodium hypochlorite solution for 4 min, 6 min and 8 mins were subcutaneously injected into mice with normal immune function(groups Al-A3 respectively, n=20 in each) and mice with immunosuppression (groups B1-B3, n=20 in each). All groups of mice began to show body discomfort on day 5 after infection and develop lumps on the back about on day 15. In groups Al-A3, animal death occurred during days 7-15, with a same survival rate of 95.0%(19/20) and infection rate of 89.4%(17/19), 73.6%(14/19) and 47.3%(9/19) respectively. In groups B1-B3, animal death occurred during days 7-50, with survival rate of 60%(13/20), 55%(11/20)and 55%(11/20) and infection rate of 76.9% (10/13), 54.5% (6/11) and 45.4% (5/11) respectively. After the scolex of cysticercus was evaginated with 15% pig bile, four suckers, an apparent rostellum and two distinct hook-like puncta structures were seen. These results indicate that mice with normal immune function can be used as a replacement of immunosuppressive mice to establish a T. asiatica oncosphere infection model. In addition, the T. asiatica eggs pre-incubated with sodium hypochlorite solution for 4 min have the strongest infection ability.

  3. Restoration of Muscle Mitochondrial Function and Metabolic Flexibility in Type 2 Diabetes by Exercise Training Is Paralleled by Increased Myocellular Fat Storage and Improved Insulin Sensitivity

    NARCIS (Netherlands)

    Meex, R.C.R.; Schrauwen-Hinderling, V.B.; Moonen-Kornips, E.; Schaart, G.; Mensink, M.R.; Phielix, E.; Weijer, van de T.; Sels, J.P.; Schrauwen, P.; Hesselink, M.K.C.

    2010-01-01

    OBJECTIVE-Mitochondrial dysfunction and fat accumulation in skeletal muscle (increased intramyocellular lipid [IMCL]) have been linked to development of type 2 diabetes. We examined whether exercise training could restore mitochondrial function and insulin sensitivity in patients with type 2

  4. The metabolic enhancer piracetam ameliorates the impairment of mitochondrial function and neurite outgrowth induced by beta-amyloid peptide.

    Science.gov (United States)

    Kurz, C; Ungerer, I; Lipka, U; Kirr, S; Schütt, T; Eckert, A; Leuner, K; Müller, W E

    2010-05-01

    beta-Amyloid peptide (Abeta) is implicated in the pathogenesis of Alzheimer's disease by initiating a cascade of events from mitochondrial dysfunction to neuronal death. The metabolic enhancer piracetam has been shown to improve mitochondrial dysfunction following brain aging and experimentally induced oxidative stress. We used cell lines (PC12 and HEK cells) and murine dissociated brain cells. The protective effects of piracetam in vitro and ex vivo on Abeta-induced impairment of mitochondrial function (as mitochondrial membrane potential and ATP production), on secretion of soluble Abeta and on neurite outgrowth in PC12 cells were investigated. Piracetam improves mitochondrial function of PC12 cells and acutely dissociated brain cells from young NMRI mice following exposure to extracellular Abeta(1-42). Similar protective effects against Abeta(1-42) were observed in dissociated brain cells from aged NMRI mice, or mice transgenic for mutant human amyloid precursor protein (APP) treated with piracetam for 14 days. Soluble Abeta load was markedly diminished in the brain of those animals after treatment with piracetam. Abeta production by HEK cells stably transfected with mutant human APP was elevated by oxidative stress and this was reduced by piracetam. Impairment of neuritogenesis is an important consequence of Abeta-induced mitochondrial dysfunction and Abeta-induced reduction of neurite growth in PC12 cells was substantially improved by piracetam. Our findings strongly support the concept of improving mitochondrial function as an approach to ameliorate the detrimental effects of Abeta on brain function.

  5. Defective mitochondrial function in vivo in skeletal muscle in adults with Down's syndrome: a 31P-MRS study.

    Directory of Open Access Journals (Sweden)

    Alexander C Phillips

    Full Text Available Down's syndrome (DS is a developmental disorder associated with intellectual disability (ID. We have previously shown that people with DS engage in very low levels of exercise compared to people with ID not due to DS. Many aspects of the DS phenotype, such as dementia, low activity levels and poor muscle tone, are shared with disorders of mitochondrial origin, and mitochondrial dysfunction has been demonstrated in cultured DS tissue. We undertook a phosphorus magnetic resonance spectroscopy ((31P-MRS study in the quadriceps muscle of 14 people with DS and 11 non-DS ID controls to investigate the post-exercise resynthesis kinetics of phosphocreatine (PCr, which relies on mitochondrial respiratory function and yields a measure of muscle mitochondrial function in vivo. We found that the PCr recovery rate constant was significantly decreased in adults with DS compared to non-DS ID controls (1.7 ± 0.1 min(-1 vs 2.1 ± 0.1 min(-1 respectively who were matched for physical activity levels, indicating that muscle mitochondrial function in vivo is impaired in DS. This is the first study to investigate mitochondrial function in vivo in DS using (31P-MRS. Our study is consistent with previous in vitro studies, supporting a theory of a global mitochondrial defect in DS.

  6. Hypoxia-inducible factor-1α activation improves renal oxygenation and mitochondrial function in early chronic kidney disease.

    Science.gov (United States)

    Thomas, Joanna L; Pham, Hai; Li, Ying; Hall, Elanore; Perkins, Guy A; Ali, Sameh S; Patel, Hemal H; Singh, Prabhleen

    2017-08-01

    The pathophysiology of chronic kidney disease (CKD) is driven by alterations in surviving nephrons to sustain renal function with ongoing nephron loss. Oxygen supply-demand mismatch, due to hemodynamic adaptations, with resultant hypoxia, plays an important role in the pathophysiology in early CKD. We sought to investigate the underlying mechanisms of this mismatch. We utilized the subtotal nephrectomy (STN) model of CKD to investigate the alterations in renal oxygenation linked to sodium (Na) transport and mitochondrial function in the surviving nephrons. Oxygen delivery was significantly reduced in STN kidneys because of lower renal blood flow. Fractional oxygen extraction was significantly higher in STN. Tubular Na reabsorption was significantly lower per mole of oxygen consumed in STN. We hypothesized that decreased mitochondrial bioenergetic capacity may account for this and uncovered significant mitochondrial dysfunction in the early STN kidney: higher oxidative metabolism without an attendant increase in ATP levels, elevated superoxide levels, and alterations in mitochondrial morphology. We further investigated the effect of activation of hypoxia-inducible factor-1α (HIF-1α), a master regulator of cellular hypoxia response. We observed significant improvement in renal blood flow, glomerular filtration rate, and tubular Na reabsorption per mole of oxygen consumed with HIF-1α activation. Importantly, HIF-1α activation significantly lowered mitochondrial oxygen consumption and superoxide production and increased mitochondrial volume density. In conclusion, we report significant impairment of renal oxygenation and mitochondrial function at the early stages of CKD and demonstrate the beneficial role of HIF-1α activation on renal function and metabolism.

  7. Fe(III Is Essential for Porcine Embryonic Development via Mitochondrial Function Maintenance.

    Directory of Open Access Journals (Sweden)

    Ming-Hui Zhao

    Full Text Available Iron is an important trace element involved in several biological processes. The role of iron in porcine early embryonic development remains unknown. In the present study, we depleted iron (III, Fe3+ with deferoxamine (DFM, a specific Fe3+ chelator, in cultured porcine parthenotes and monitored embryonic development, apoptosis, mitochondrial membrane potential, and ATP production. Results showed biphasic function of Fe3+ in porcine embryo development. 0.5 μM DFM obviously increased blastocyst formation (57.49 ± 2.18% vs. control, 43.99 ± 1.72%, P < 0.05 via reduced (P < 0.05 production of reactive oxygen species (ROS, further increased mitochondrial membrane potential and ATP production in blastocysts (P < 0.05. 0.5 μM DFM decreased mRNA expression of Caspase 3 (Casp3 and increased Bcl-xL. However, results showed a significant reduction in blastocyst formation in the presence of 5.0 μM DFM compared with the control group (DFM, 21.62 ± 3.92% vs. control, 43.99 ± 1.73%, P < 0.05. Fe3+ depletion reduced the total (DFM, 21.10 ± 8.78 vs. control, 44.09 ± 13.65, P < 0.05 and increased apoptotic cell number (DFM, 11.10 ± 5.24 vs. control, 2.64 ± 1.43, P < 0.05 in the blastocyst. An obvious reduction in mitochondrial membrane potential and ATP level after 5.0 μM DFM treatment was observed. Co-localization between mitochondria and cytochrome c was reduced after high concentration of DFM treatment. In conclusion, Fe3+ is essential for porcine embryonic development via mitochondrial function maintenance, but redundant Fe3+ impairs the function of mitochondria.

  8. A novel method for determining human ex vivo submaximal skeletal muscle mitochondrial function

    DEFF Research Database (Denmark)

    Hey-Mogensen, Martin; Gram, Martin; Jensen, Martin Borch

    2015-01-01

    previously used. Muscle biopsies were taken from 64 old or young male subjects (60-70 or 20-30 years old). Aged subjects were recruited as trained or untrained. Muscle biopsies were used for isolation of mitochondria and subsequent measurements of DNA repair, antioxidant capacity and mitochondrial protein......In spite of numerous studies there is no consensus whether mitochondrial function is altered with increased age. The novelty of the present study is the determination of mitochondrial function at submaximal activity rates which is more physiological relevant than the ex vivo functionality protocols...... levels (complex I-V). Mitochondrial function was determined by simultaneous measures of oxygen consumption, membrane potential and hydrogen peroxide emission using pyruvate+malate (PM) or succinate+rotenone (SR) as substrates. Proton leak was lower in aged subjects when determined at the same membrane...

  9. Elevated mitochondrial oxidative stress impairs metabolic adaptations to exercise in skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Justin D Crane

    Full Text Available Mitochondrial oxidative stress is a complex phenomenon that is inherently tied to energy provision and is implicated in many metabolic disorders. Exercise training increases mitochondrial oxidative capacity in skeletal muscle yet it remains unclear if oxidative stress plays a role in regulating these adaptations. We demonstrate that the chronic elevation in mitochondrial oxidative stress present in Sod2 (+/- mice impairs the functional and biochemical mitochondrial adaptations to exercise. Following exercise training Sod2 (+/- mice fail to increase maximal work capacity, mitochondrial enzyme activity and mtDNA copy number, despite a normal augmentation of mitochondrial proteins. Additionally, exercised Sod2 (+/- mice cannot compensate for their higher amount of basal mitochondrial oxidative damage and exhibit poor electron transport chain complex assembly that accounts for their compromised adaptation. Overall, these results demonstrate that chronic skeletal muscle mitochondrial oxidative stress does not impact exercise induced mitochondrial biogenesis, but impairs the resulting mitochondrial protein function and can limit metabolic plasticity.

  10. Elevated Mitochondrial Oxidative Stress Impairs Metabolic Adaptations to Exercise in Skeletal Muscle

    Science.gov (United States)

    Crane, Justin D.; Abadi, Arkan; Hettinga, Bart P.; Ogborn, Daniel I.; MacNeil, Lauren G.; Steinberg, Gregory R.; Tarnopolsky, Mark A.

    2013-01-01

    Mitochondrial oxidative stress is a complex phenomenon that is inherently tied to energy provision and is implicated in many metabolic disorders. Exercise training increases mitochondrial oxidative capacity in skeletal muscle yet it remains unclear if oxidative stress plays a role in regulating these adaptations. We demonstrate that the chronic elevation in mitochondrial oxidative stress present in Sod2 +/- mice impairs the functional and biochemical mitochondrial adaptations to exercise. Following exercise training Sod2 +/- mice fail to increase maximal work capacity, mitochondrial enzyme activity and mtDNA copy number, despite a normal augmentation of mitochondrial proteins. Additionally, exercised Sod2 +/- mice cannot compensate for their higher amount of basal mitochondrial oxidative damage and exhibit poor electron transport chain complex assembly that accounts for their compromised adaptation. Overall, these results demonstrate that chronic skeletal muscle mitochondrial oxidative stress does not impact exercise induced mitochondrial biogenesis, but impairs the resulting mitochondrial protein function and can limit metabolic plasticity. PMID:24324727

  11. Decreased endothelial nitric oxide synthase expression and function contribute to impaired mitochondrial biogenesis and oxidative stress in fetal lambs with persistent pulmonary hypertension.

    Science.gov (United States)

    Afolayan, Adeleye J; Eis, Annie; Alexander, Maxwell; Michalkiewicz, Teresa; Teng, Ru-Jeng; Lakshminrusimha, Satyan; Konduri, Girija G

    2016-01-01

    Impaired vasodilation in persistent pulmonary hypertension of the newborn (PPHN) is characterized by mitochondrial dysfunction. We investigated the hypothesis that a decreased endothelial nitric oxide synthase level leads to impaired mitochondrial biogenesis and function in a lamb model of PPHN induced by prenatal ductus arteriosus constriction. We ventilated PPHN lambs with 100% O2 alone or with inhaled nitric oxide (iNO). We treated pulmonary artery endothelial cells (PAECs) from normal and PPHN lambs with detaNONOate, an NO donor. We observed decreased mitochondrial (mt) DNA copy number, electron transport chain (ETC) complex subunit levels, and ATP levels in PAECs and lung tissue of PPHN fetal lambs at baseline compared with gestation matched controls. Phosphorylation of AMP-activated kinase (AMPK) and levels of peroxisome proliferator-activated receptor-γ coactivator 1-α (PGC-1α) and sirtuin-1, which facilitate mitochondrial biogenesis, were decreased in PPHN. Ventilation with 100% O2 was associated with larger decreases in ETC subunits in the lungs of PPHN lambs compared with unventilated PPHN lambs. iNO administration, which facilitated weaning of FiO2 , partly restored mtDNA copy number, ETC subunit levels, and ATP levels. DetaNONOate increased eNOS phosphorylation and its interaction with heat shock protein 90 (HSP90); increased levels of superoxide dismutase 2 (SOD2) mRNA, protein, and activity; and decreased the mitochondrial superoxide levels in PPHN-PAECs. Knockdown of eNOS decreased ETC protein levels in control PAECs. We conclude that ventilation with 100% O2 amplifies oxidative stress and mitochondrial dysfunction in PPHN, which are partly improved by iNO and weaning of oxygen. Copyright © 2016 the American Physiological Society.

  12. Cytokine and nitric oxide levels in patients with sepsis--temporal evolvement and relation to platelet mitochondrial respiratory function

    DEFF Research Database (Denmark)

    Sjövall, Fredrik; Morota, Saori; Frostner, Eleonor Åsander

    2014-01-01

    BACKGROUND: The levels of nitric oxide (NO) and various cytokines are known to be increased during sepsis. These signaling molecules could potentially act as regulators and underlie the enhancement of mitochondrial function described in the later phase of sepsis. Therefore, we investigated...... the correlation between observed changes in platelet mitochondrial respiration and a set of pro- and anti-inflammatory cytokines as well as NO plasma levels in patients with sepsis. METHODS AND RESULTS: Platelet mitochondrial respiration and levels of TNFα, MCP-1 (monocyte chemotactic protein-1), INFγ (interferon......-γ), IL-1β, IL-4, IL-5, IL-6, IL-8, IL-10 and IL-17 and NO were analyzed in 38 patients with severe sepsis or septic shock at three time points during one week following admission to the ICU. Citrate synthase, mitochondrial DNA and cytochrome c were measured as markers of cellular mitochondrial content...

  13. Mitochondrial function in type I cells isolated from rabbit arterial chemoreceptors.

    Science.gov (United States)

    Duchen, M R; Biscoe, T J

    1992-05-01

    1. In this, and the accompanying paper (Duchen & Biscoe, 1992), we test the hypothesis that the oxygen sensitivity of mitochondrial electron transport forms a basis for transduction in the carotid body, the primary peripheral arterial oxygen sensor. We here describe for isolated type I cells the changes in autofluorescence of mitochondrial NAD(P)H that accompany changes in PO2. 2. NAD(P)H autofluorescence (excitation, 340-360 nm; emission peak, 450 nm) increased with anoxia, reflecting a rise in the NAD(P)H/NAD(P) ratio. Graded increases in autofluorescence were seen in response to graded decreases in PO2, suggesting that mitochondrial function is progressively altered below a PO2 of about 60 mmHg. 3. A mitochondrial origin for the NAD(P)H autofluorescence was suggested by the mutual exclusion of the responses to anoxia and cyanide. 4. Oxidized flavoproteins fluoresce when excited at 450 nm with an emission peak at 550 nm. The small signals obtained under these conditions increased with uncoupler and showed a graded decrease with falling PO2 reflecting a rise in the FADH/FAD ratio. 5. Hypoxia raises [Ca2+]i. The hypoxia-induced changes in mitochondrial function were not secondary to this rise. A brief K(+)-induced depolarization leads to a transient increase in [Ca2+]i. At the same time there is a rapid decrease in NAD(P)H autofluorescence followed by an increase that far outlasts the rise in [Ca2+]i. This delayed increase in autofluorescence was smaller than was the increase with anoxia, even though K(+)-induced depolarization raised [Ca2+]i more than does anoxia. In Ca(2+)-free solutions the depolarization-induced changes were abolished, while those associated with hypoxia were maintained. 6. The changes of autofluorescence with K(+)-induced depolarization appear to reflect (i) oxidation of NAD(P)H by stimulation of respiration following mitochondrial Ca2+ uptake and (ii) reduction of NAD(P) by the Ca(2+)-dependent activation of mitochondrial dehydrogenases. This

  14. Xanthurenic acid translocates proapoptotic Bcl-2 family proteins into mitochondria and impairs mitochondrial function

    Directory of Open Access Journals (Sweden)

    Hess Otto M

    2004-04-01

    Full Text Available Abstract Background Xanthurenic acid is an endogenous molecule produced by tryptophan degradation, produced in the cytoplasm and mitochondria. Its accumulation can be observed in aging-related diseases, e.g. senile cataract and infectious disease. We previously reported that xanthurenic acid provokes apoptosis, and now present a study of the response of mitochondria to xanthurenic acid. Results Xanthurenic acid at 10 or 20 μM in culture media of human aortic smooth muscle cells induces translocation of the proteins Bax, Bak, Bclxs, and Bad into mitochondria. In 20 μM xanthurenic acid, Bax is also translocated to the nucleus. In isolated mitochondria xanthurenic acid leads to Bax and Bclxs oligomerization, accumulation of Ca2+, and increased oxygen consumption. Conclusion Xanthurenic acid interacts directly with Bcl-2 family proteins, inducing mitochondrial pathways of apoptosis and impairing mitochondrial functions.

  15. Functional neuroimaging of normal aging: Declining brain, adapting brain.

    Science.gov (United States)

    Sugiura, Motoaki

    2016-09-01

    Early functional neuroimaging research on normal aging brain has been dominated by the interest in cognitive decline. In this framework the age-related compensatory recruitment of prefrontal cortex, in terms of executive system or reduced lateralization, has been established. Further details on these compensatory mechanisms and the findings reflecting cognitive decline, however, remain the matter of intensive investigations. Studies in another framework where age-related neural alteration is considered adaptation to the environmental change are recently burgeoning and appear largely categorized into three domains. The age-related increase in activation of the sensorimotor network may reflect the alteration of the peripheral sensorimotor systems. The increased susceptibility of the network for the mental-state inference to the socioemotional significance may be explained by the age-related motivational shift due to the altered social perception. The age-related change in activation of the self-referential network may be relevant to the focused positive self-concept of elderly driven by a similar motivational shift. Across the domains, the concept of the self and internal model may provide the theoretical bases of this adaptation framework. These two frameworks complement each other to provide a comprehensive view of the normal aging brain. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. PDE 5 inhibitor improves insulin sensitivity by enhancing mitochondrial function in adipocytes.

    Science.gov (United States)

    Yu, Hea Min; Chung, Hyo Kyun; Kim, Koon Soon; Lee, Jae Min; Hong, Jun Hwa; Park, Kang Seo

    2017-11-04

    Adipocytes are involved in many metabolic disorders. It was recently reported that phosphodiesterase type 5 (PDE5) is expressed in human adipose tissue. In addition, PDE5 inhibitors have been shown to improve insulin sensitivity in humans. However, the mechanism underlying the role of PDE5 inhibitors as an insulin sensitizer remains largely unknown. The present study was undertaken to investigate the role of the PDE5 inhibitor udenafil in insulin signaling in adipocytes and whether this is mediated through the regulation of mitochondrial function. To study the mechanism underlying the insulin sensitizing action of PDE5 inhibitors, we evaluated quantitative changes in protein or mRNA levels of mitochondrial oxidative phosphorylation (OxPhos) complex, oxygen consumption rate (OCR), and fatty acid oxidation with varying udenafil concentrations in 3T3-L1 cells. Our cell study suggested that udenafil enhanced the insulin signaling pathway in 3T3-L1 cells. Following udenafil treatment, basal mitochondrial OCR, maximal OxPhos capacity, and OxPhos gene expression significantly increased. Finally, we examined whether udenafil can affect the fatty acid oxidation process. Treatment of 3T3-L1 cells with udenafil (10 and 20 μM) significantly increased fatty acid oxidation rate in a dose-dependent manner. In addition, the expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) significantly increased. We demonstrated that the PDE5 inhibitor udenafil enhances insulin sensitivity by improving mitochondrial function in 3T3-L1 cells. This might be the mechanism underlying the PDE5 inhibitor-enhanced insulin signaling in adipocytes. This also suggests that udenafil may provide benefit in the treatment of type 2 diabetes and other related cardiovascular diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. PINK1 is necessary for long term survival and mitochondrial function in human dopaminergic neurons.

    Directory of Open Access Journals (Sweden)

    Alison Wood-Kaczmar

    2008-06-01

    Full Text Available Parkinson's disease (PD is a common age-related neurodegenerative disease and it is critical to develop models which recapitulate the pathogenic process including the effect of the ageing process. Although the pathogenesis of sporadic PD is unknown, the identification of the mendelian genetic factor PINK1 has provided new mechanistic insights. In order to investigate the role of PINK1 in Parkinson's disease, we studied PINK1 loss of function in human and primary mouse neurons. Using RNAi, we created stable PINK1 knockdown in human dopaminergic neurons differentiated from foetal ventral mesencephalon stem cells, as well as in an immortalised human neuroblastoma cell line. We sought to validate our findings in primary neurons derived from a transgenic PINK1 knockout mouse. For the first time we demonstrate an age dependent neurodegenerative phenotype in human and mouse neurons. PINK1 deficiency leads to reduced long-term viability in human neurons, which die via the mitochondrial apoptosis pathway. Human neurons lacking PINK1 demonstrate features of marked oxidative stress with widespread mitochondrial dysfunction and abnormal mitochondrial morphology. We report that PINK1 plays a neuroprotective role in the mitochondria of mammalian neurons, especially against stress such as staurosporine. In addition we provide evidence that cellular compensatory mechanisms such as mitochondrial biogenesis and upregulation of lysosomal degradation pathways occur in PINK1 deficiency. The phenotypic effects of PINK1 loss-of-function described here in mammalian neurons provides mechanistic insight into the age-related degeneration of nigral dopaminergic neurons seen in PD.

  18. AMPK Activation Prevents and Reverses Drug-Induced Mitochondrial and Hepatocyte Injury by Promoting Mitochondrial Fusion and Function.

    Directory of Open Access Journals (Sweden)

    Sun Woo Sophie Kang

    Full Text Available Mitochondrial damage is the major factor underlying drug-induced liver disease but whether conditions that thwart mitochondrial injury can prevent or reverse drug-induced liver damage is unclear. A key molecule regulating mitochondria quality control is AMP activated kinase (AMPK. When activated, AMPK causes mitochondria to elongate/fuse and proliferate, with mitochondria now producing more ATP and less reactive oxygen species. Autophagy is also triggered, a process capable of removing damaged/defective mitochondria. To explore whether AMPK activation could potentially prevent or reverse the effects of drug-induced mitochondrial and hepatocellular damage, we added an AMPK activator to collagen sandwich cultures of rat and human hepatocytes exposed to the hepatotoxic drugs, acetaminophen or diclofenac. In the absence of AMPK activation, the drugs caused hepatocytes to lose polarized morphology and have significantly decreased ATP levels and viability. At the subcellular level, mitochondria underwent fragmentation and had decreased membrane potential due to decreased expression of the mitochondrial fusion proteins Mfn1, 2 and/or Opa1. Adding AICAR, a specific AMPK activator, at the time of drug exposure prevented and reversed these effects. The mitochondria became highly fused and ATP production increased, and hepatocytes maintained polarized morphology. In exploring the mechanism responsible for this preventive and reversal effect, we found that AMPK activation prevented drug-mediated decreases in Mfn1, 2 and Opa1. AMPK activation also stimulated autophagy/mitophagy, most significantly in acetaminophen-treated cells. These results suggest that activation of AMPK prevents/reverses drug-induced mitochondrial and hepatocellular damage through regulation of mitochondrial fusion and autophagy, making it a potentially valuable approach for treatment of drug-induced liver injury.

  19. AMPK Activation Prevents and Reverses Drug-Induced Mitochondrial and Hepatocyte Injury by Promoting Mitochondrial Fusion and Function

    Science.gov (United States)

    Taniane, Caitlin; Farrell, Geoffrey; Arias, Irwin M.; Lippincott-Schwartz, Jennifer; Fu, Dong

    2016-01-01

    Mitochondrial damage is the major factor underlying drug-induced liver disease but whether conditions that thwart mitochondrial injury can prevent or reverse drug-induced liver damage is unclear. A key molecule regulating mitochondria quality control is AMP activated kinase (AMPK). When activated, AMPK causes mitochondria to elongate/fuse and proliferate, with mitochondria now producing more ATP and less reactive oxygen species. Autophagy is also triggered, a process capable of removing damaged/defective mitochondria. To explore whether AMPK activation could potentially prevent or reverse the effects of drug-induced mitochondrial and hepatocellular damage, we added an AMPK activator to collagen sandwich cultures of rat and human hepatocytes exposed to the hepatotoxic drugs, acetaminophen or diclofenac. In the absence of AMPK activation, the drugs caused hepatocytes to lose polarized morphology and have significantly decreased ATP levels and viability. At the subcellular level, mitochondria underwent fragmentation and had decreased membrane potential due to decreased expression of the mitochondrial fusion proteins Mfn1, 2 and/or Opa1. Adding AICAR, a specific AMPK activator, at the time of drug exposure prevented and reversed these effects. The mitochondria became highly fused and ATP production increased, and hepatocytes maintained polarized morphology. In exploring the mechanism responsible for this preventive and reversal effect, we found that AMPK activation prevented drug-mediated decreases in Mfn1, 2 and Opa1. AMPK activation also stimulated autophagy/mitophagy, most significantly in acetaminophen-treated cells. These results suggest that activation of AMPK prevents/reverses drug-induced mitochondrial and hepatocellular damage through regulation of mitochondrial fusion and autophagy, making it a potentially valuable approach for treatment of drug-induced liver injury. PMID:27792760

  20. Effects of dietary leucine supplementation on the hepatic mitochondrial biogenesis and energy metabolism in normal birth weight and intrauterine growth-retarded weanling piglets.

    Science.gov (United States)

    Su, Weipeng; Xu, Wen; Zhang, Hao; Ying, Zhixiong; Zhou, Le; Zhang, Lili; Wang, Tian

    2017-04-01

    The study was conducted to evaluate the effects of dietary leucine supplementation on mitochondrial biogenesis and energy metabolism in the liver of normal birth weight (NBW) and intrauterine growth-retarded (IUGR) weanling piglets. A total of sixteen pairs of NBW and IUGR piglets from sixteen sows were selected according to their birth weight. At postnatal day 14, all piglets were weaned and fed either a control diet or a leucine-supplemented diet for 21 d. Thereafter, a 2 × 2 factorial experimental design was used. Each treatment consisted of eight replications with one piglet per replication. Compared with NBW piglets, IUGR piglets had a decreased ( P supplementation increased ( P supplemented diet exhibited increases ( P supplementation may exert beneficial effects on mitochondrial biogenesis and energy metabolism in NBW and IUGR weanling piglets.

  1. Therapeutic effects of antibiotic drug mefloquine against cervical cancer through impairing mitochondrial function and inhibiting mTOR pathway.

    Science.gov (United States)

    Li, Hui; Jiao, Shun; Li, Xin; Banu, Hasina; Hamal, Shreejana; Wang, Xianrong

    2017-01-01

    Targeting mitochondria is an attractive strategy for cancer therapy due to the essential roles of mitochondria in cancer cell energy metabolism. In this study, we show that mefloquine, an antibiotic drug, effectively targets cervical cancer cells through impairing mitochondrial function. Mefloquine dose-dependently induces apoptosis and inhibits proliferation and anchorage-independent colony formation of multiple cervical cancer cell lines. Mefloquine alone inhibits cervical tumor growth in vivo and its combination with paclitaxel is synergistic in inhibiting tumor growth. Mechanistically, mefloquine inhibits mitochondrial function via inhibiting mitochondrial respiration, decreasing membrane potential, increasing ROS generation, and decreasing ATP level. We further show that mefloquine suppresses activation of mTOR signaling pathway in HeLa cells. However, the inhibitory effects of mefloquine on survival, colony formation, and ATP are abolished in mitochondrial respiration-deficient HeLa ρ 0 cells, demonstrating that mefloquine acts on cervical cancer cells via targeting mitochondrial respiration. Inhibition of mTOR signaling pathway by mefloquine was also reversed in HeLa ρ 0 cells, suggesting deactivation of mTOR pathway as a consequence of mitochondria function disruption. Our work suggests that mefloquine is a potential candidate for cervical cancer treatment. Our work also highlights the therapeutic value of anti-mitochondria and establishes the association of mitochondrial function and the activation of mTOR signaling pathway in cervical cancer cells.

  2. The fungicide Pristine® inhibits mitochondrial function in vitro but not flight metabolic rates in honey bees.

    Science.gov (United States)

    Campbell, Jacob B; Nath, Rachna; Gadau, Juergen; Fox, Trevor; DeGrandi-Hoffman, Gloria; Harrison, Jon F

    2016-03-01

    Honey bees and other pollinators are exposed to fungicides that act by inhibiting fungal mitochondria. Here we test whether a common fungicide (Pristine®) inhibits the function of mitochondria of honeybees, and whether consumption of ecologically-realistic concentrations can cause negative effects on the mitochondria of flight muscles, or the capability for flight, as judged by CO2 emission rates and thorax temperatures during flight. Direct exposure of mitochondria to Pristine® levels above 5 ppm strongly inhibited mitochondrial oxidation rates in vitro. However, bees that consumed pollen containing Pristine® at ecologically-realistic concentrations (≈ 1 ppm) had normal flight CO2 emission rates and thorax temperatures. Mitochondria isolated from the flight muscles of the Pristine®-consuming bees had higher state 3 oxygen consumption rates than control bees, suggesting that possibly Pristine®-consumption caused compensatory changes in mitochondria. It is likely that the lack of a strong functional effect of Pristine®-consumption on flight performance and the in vitro function of flight muscle mitochondria results from maintenance of Pristine® levels in the flight muscles at much lower levels than occur in the food, probably due to metabolism and detoxification. As Pristine® has been shown to negatively affect feeding rates and protein digestion of honey bees, it is plausible that Pristine® consumption negatively affects gut wall function (where mitochondria may be exposed to higher concentrations of Pristine®). Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Separation of the gluconeogenic and mitochondrial functions of pgc-1α through s6 kinase

    DEFF Research Database (Denmark)

    Lustig, Y.; Ruas, J.L.; Estall, J.L.

    2011-01-01

    and gluconeogenesis and fatty acid oxidation in the liver. We show here that S6 kinase, activated in the liver upon feeding, can phosphorylate PGC-1α directly on two sites within its arginine/serine-rich (RS) domain. This phosphorylation significantly attenuates the ability of PGC-1α to turn on genes...... of gluconeogenesis in cultured hepatocytes and in vivo, while leaving the functions of PGC-1α as an activator of mitochondrial and fatty acid oxidation genes completely intact. These phosphorylations interfere with the ability of PGC-1α to bind to HNF4α, a transcription factor required for gluconeogenesis, while...

  4. Cisplatin impairs rat liver mitochondrial functions by inducing changes on membrane ion permeability: Prevention by thiol group protecting agents

    International Nuclear Information System (INIS)

    Custodio, Jose B.A.; Cardoso, Carla M.P.; Santos, Maria S.; Almeida, Leonor M.; Vicente, Joaquim A.F.; Fernandes, Maria A.S.

    2009-01-01

    Cisplatin (CisPt) is the most important platinum anticancer drug widely used in the treatment of head, neck, ovarian and testicular cancers. However, the mechanisms by which CisPt induces cytotoxicity, namely hepatotoxicity, are not completely understood. The goal of this study was to investigate the influence of CisPt on rat liver mitochondrial functions (Ca 2+ -induced mitochondrial permeability transition (MPT), mitochondrial bioenergetics, and mitochondrial oxidative stress) to better understand the mechanism underlying its hepatotoxicity. The effect of thiol group protecting agents and some antioxidants against CisPt-induced mitochondrial damage was also investigated. Treatment of rat liver mitochondria with CisPt (20 nmol/mg protein) induced Ca 2+ -dependent mitochondrial swelling, depolarization of membrane potential (ΔΨ), Ca 2+ release, and NAD(P)H fluorescence intensity decay. These effects were prevented by cyclosporine A (CyA), a potent and specific inhibitor of the MPT. In the concentration range of up to 40 nmol/mg protein, CisPt slightly inhibited state 3 and stimulated state 2 and state 4 respiration rates using succinate as respiratory substrate. The respiratory indexes, respiratory control ratio (RCR) and ADP/O ratios, the ΔΨ, and the ADP phosphorylation rate were also depressed. CisPt induced mitochondrial inner membrane permeabilization to protons (proton leak) but did not induce significant changes on mitochondrial H 2 O 2 generation. All the effects induced by CisPt on rat liver mitochondria were prevented by thiol group protecting agents namely, glutathione (GSH), dithiothreitol (DTT), N-acetyl-L-cysteine (NAC) and cysteine (CYS), whereas superoxide-dismutase (SOD), catalase (CAT) and ascorbate (ASC) were without effect. In conclusion, the anticancer drug CisPt: (1) increases the sensitivity of mitochondria to Ca 2+ -induced MPT; (2) interferes with mitochondrial bioenergetics by increasing mitochondrial inner membrane permeabilization to

  5. Time-Dependent and Organ-Specific Changes in Mitochondrial Function, Mitochondrial DNA Integrity, Oxidative Stress and Mononuclear Cell Infiltration in a Mouse Model of Burn Injury.

    Directory of Open Access Journals (Sweden)

    Bartosz Szczesny

    Full Text Available Severe thermal injury induces a pathophysiological response that affects most of the organs within the body; liver, heart, lung, skeletal muscle among others, with inflammation and hyper-metabolism as a hallmark of the post-burn damage. Oxidative stress has been implicated as a key component in development of inflammatory and metabolic responses induced by burn. The goal of the current study was to evaluate several critical mitochondrial functions in a mouse model of severe burn injury. Mitochondrial bioenergetics, measured by Extracellular Flux Analyzer, showed a time dependent, post-burn decrease in basal respiration and ATP-turnover but enhanced maximal respiratory capacity in mitochondria isolated from the liver and lung of animals subjected to burn injury. Moreover, we detected a tissue-specific degree of DNA damage, particularly of the mitochondrial DNA, with the most profound effect detected in lungs and hearts of mice subjected to burn injury. Increased mitochondrial biogenesis in lung tissue in response to burn injury was also observed. Burn injury also induced time dependent increases in oxidative stress (measured by amount of malondialdehyde and neutrophil infiltration (measured by myeloperoxidase activity, particularly in lung and heart. Tissue mononuclear cell infiltration was also confirmed by immunohistochemistry. The amount of poly(ADP-ribose polymers decreased in the liver, but increased in the heart in later time points after burn. All of these biochemical changes were also associated with histological alterations in all three organs studied. Finally, we detected a significant increase in mitochondrial DNA fragments circulating in the blood immediately post-burn. There was no evidence of systemic bacteremia, or the presence of bacterial DNA fragments at any time after burn injury. The majority of the measured parameters demonstrated a sustained elevation even at 20-40 days post injury suggesting a long-lasting effect of thermal

  6. PTENα, a PTEN isoform translated through alternative initiation, regulates mitochondrial function and energy metabolism.

    Science.gov (United States)

    Liang, Hui; He, Shiming; Yang, Jingyi; Jia, Xinying; Wang, Pan; Chen, Xi; Zhang, Zhong; Zou, Xiajuan; McNutt, Michael A; Shen, Wen Hong; Yin, Yuxin

    2014-05-06

    PTEN is one of the most frequently mutated genes in human cancer. It is known that PTEN has a wide range of biological functions beyond tumor suppression. Here, we report that PTENα, an N-terminally extended form of PTEN, functions in mitochondrial metabolism. Translation of PTENα is initiated from a CUG codon upstream of and in-frame with the coding region of canonical PTEN. Eukaryotic translation initiation factor 2A (eIF2A) controls PTENα translation, which requires a CUG-centered palindromic motif. We show that PTENα induces cytochrome c oxidase activity and ATP production in mitochondria. TALEN-mediated somatic deletion of PTENα impairs mitochondrial respiratory chain function. PTENα interacts with canonical PTEN to increase PINK1 protein levels and promote energy production. Our studies demonstrate the importance of eIF2A-mediated alternative translation for generation of protein diversity in eukaryotic systems and provide insights into the mechanism by which the PTEN family is involved in multiple cellular processes. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Characteristic functions of scale mixtures of multivariate skew-normal distributions

    KAUST Repository

    Kim, Hyoung-Moon

    2011-08-01

    We obtain the characteristic function of scale mixtures of skew-normal distributions both in the univariate and multivariate cases. The derivation uses the simple stochastic relationship between skew-normal distributions and scale mixtures of skew-normal distributions. In particular, we describe the characteristic function of skew-normal, skew-t, and other related distributions. © 2011 Elsevier Inc.

  8. Effects of methyl and inorganic mercury exposure on genome homeostasis and mitochondrial function in Caenorhabditis elegans.

    Science.gov (United States)

    Wyatt, Lauren H; Luz, Anthony L; Cao, Xiou; Maurer, Laura L; Blawas, Ashley M; Aballay, Alejandro; Pan, William K Y; Meyer, Joel N

    2017-04-01

    Mercury toxicity mechanisms have the potential to induce DNA damage and disrupt cellular processes, like mitochondrial function. Proper mitochondrial function is important for cellular bioenergetics and immune signaling and function. Reported impacts of mercury on the nuclear genome (nDNA) are conflicting and inconclusive, and mitochondrial DNA (mtDNA) impacts are relatively unknown. In this study, we assessed genotoxic (mtDNA and nDNA), metabolic, and innate immune impacts of inorganic and organic mercury exposure in Caenorhabditis elegans. Genotoxic outcomes measured included DNA damage, DNA damage repair (nucleotide excision repair, NER; base excision repair, BER), and genomic copy number following MeHg and HgCl 2 exposure alone and in combination with known DNA damage-inducing agents ultraviolet C radiation (UVC) and hydrogen peroxide (H 2 O 2 ), which cause bulky DNA lesions and oxidative DNA damage, respectively. Following exposure to both MeHg and HgCl 2 , low-level DNA damage (∼0.25 lesions/10kb mtDNA and nDNA) was observed. Unexpectedly, a higher MeHg concentration reduced damage in both genomes compared to controls. However, this observation was likely the result of developmental delay. In co-exposure treatments, both mercury compounds increased initial DNA damage (mtDNA and nDNA) in combination with H 2 O 2 exposure, but had no impact in combination with UVC exposure. Mercury exposure both increased and decreased DNA damage removal via BER. DNA repair after H 2 O 2 exposure in mercury-exposed nematodes resulted in damage levels lower than measured in controls. Impacts to NER were not detected. mtDNA copy number was significantly decreased in the MeHg-UVC and MeHg-H 2 O 2 co-exposure treatments. Mercury exposure had metabolic impacts (steady-state ATP levels) that differed between the compounds; HgCl 2 exposure decreased these levels, while MeHg slightly increased levels or had no impact. Both mercury species reduced mRNA levels for immune signaling

  9. Abnormal mitochondrial function in locomotor and respiratory muscles of COPD patients.

    Science.gov (United States)

    Puente-Maestu, L; Pérez-Parra, J; Godoy, R; Moreno, N; Tejedor, A; González-Aragoneses, F; Bravo, J-L; Alvarez, F Villar; Camaño, S; Agustí, A

    2009-05-01

    Several cellular and molecular alterations have been described in skeletal and respiratory muscles of patients with chronic obstructive pulmonary disease (COPD), but information on potential abnormalities of mitochondrial function is scarce. The aim of the present study was to investigate mitochondrial function in the vastus lateralis (VL) and external intercostalis (EI) of COPD patients. Biopsies from VL and EI were obtained during surgery for lung cancer in 13 patients with mild to moderate COPD (age 68+/-6 yrs, forced expiratory volume in one second (FEV(1)) 66+/-15% predicted) and 19 control subjects (age 67+/-9 yrs, FEV(1) 95+/-18% pred). State 3 and 4 mitochondrial oxygen consumption (V'(O(2),m)), ATP synthesis, citrate synthase, cytochrome oxidase (COX) and complex I-III activities, as well as reactive oxygen species (ROS) production, were determined. In COPD patients, in both muscles, COX activity (VL: COPD 3.0+/-0.8 versus control 2.0+/-0.8; EI: 3.7+/-1.6 versus 2.4+/-0.9 micromol min(-1) mg(-1)) and ROS production (VL: 1,643+/-290 versus 1,285+/-468; EI: 1,033+/-210 versus 848+/-288 arbitrary units) were increased, whereas state 3 V'(O(2),m) was reduced (VL: 2.9+/-0.3 versus 3.6+/-0.4; EI: 3.6+/-0.3 versus 4.1+/-0.4 mmol min(-1) kg(-1)). Skeletal muscle mitochondria of patients with chronic obstructive pulmonary disease show electron transport chain blockade and excessive production of reactive oxygen species. The concurrent involvement of both vastus lateralis and external intercostalis suggests a systemic (rather than a local) mechanism(s) already occurring in relatively early stages (Global Initiative for Chronic Obstructive Lung Disease stage II) of the disease.

  10. Cancer: Mitochondrial Origins.

    Science.gov (United States)

    Stefano, George B; Kream, Richard M

    2015-12-01

    The primacy of glucose derived from photosynthesis as an existential source of chemical energy across plant and animal phyla is universally accepted as a core principle in the biological sciences. In mammalian cells, initial processing of glucose to triose phosphate intermediates takes place within the cytosolic glycolytic pathway and terminates with temporal transport of reducing equivalents derived from pyruvate metabolism by membrane-associated respiratory complexes in the mitochondrial matrix. The intra-mitochondrial availability of molecular oxygen as the ultimate electron acceptor drives the evolutionary fashioned chemiosmotic production of ATP as a high-efficiency biological process. The mechanistic bases of carcinogenesis have demonstrated profound alteration of normative mitochondrial function, notably dysregulated respiratory processes. Accordingly, the classic Warburg effect functionally links aerobic glycolysis, aberrant production and release of lactate, and metabolic down-regulation of mitochondrial oxidative processes with the carcinogenetic phenotype. We surmise, however, that aerobic fermentation by cancer cells may also represent a developmental re-emergence of an evolutionarily conserved early phenotype, which was "sidelined" with the emergence of mitochondrial oxidative phosphorylation as a primary mechanism for ATP production in normal cells. Regardless of state-dependent physiological status in mixed populations of cancer cells, it has been established that mitochondria are functionally linked to the initiation of cancer and its progression. Biochemical, molecular, and physiological differences in cancer cell mitochondria, notably mtDNA heteroplasmy and allele-specific expression of selected nuclear genes, may represent major focal points for novel targeting and elimination of cancer cells in metastatic disease afflicting human populations. To date, and despite considerable research efforts, the practical realization of advanced mitochondrial

  11. Sulforaphane Protects against High Cholesterol-Induced Mitochondrial Bioenergetics Impairments, Inflammation, and Oxidative Stress and Preserves Pancreaticβ-Cells Function.

    Science.gov (United States)

    Carrasco-Pozo, Catalina; Tan, Kah Ni; Gotteland, Martin; Borges, Karin

    2017-01-01

    Cholesterol plays an important role in inducing pancreatic β -cell dysfunction, leading to an impaired insulin secretory response to glucose. This study aimed to determine the protective effects of sulforaphane, a natural isothiocyanate Nrf2-inducer, against cholesterol-induced pancreatic β -cells dysfunction, through molecular and cellular mechanisms involving mitochondrial bioenergetics. Sulforaphane prevented cholesterol-induced alterations in the coupling efficiency of mitochondrial respiration, improving ATP turnover and spare capacity, and averted the impairment of the electron flow at complexes I, II, and IV. Sulforaphane also attenuated the cholesterol-induced activation of the NF κ B pathway, normalizing the expression of pro- and anti-inflammatory cytokines. In addition, it also inhibited the decrease in sirtuin 1 expression and greatly increased Pgc-1α expression in Min6 cells. Sulforaphane increased the expression of antioxidant enzymes downstream of the Nrf2 pathway and prevented lipid peroxidation induced by cholesterol. The antioxidant and anti-inflammatory properties of sulforaphane and its ability to protect and improve mitochondrial bioenergetic function contribute to its protective action against cholesterol-induced pancreatic β -cell dysfunction. Our data provide a scientifically tested foundation upon which sulforaphane can be developed as nutraceutical to preserve β -cell function and eventually control hyperglycemia.

  12. Sulforaphane Protects against High Cholesterol-Induced Mitochondrial Bioenergetics Impairments, Inflammation, and Oxidative Stress and Preserves Pancreatic β-Cells Function

    Directory of Open Access Journals (Sweden)

    Catalina Carrasco-Pozo

    2017-01-01

    Full Text Available Cholesterol plays an important role in inducing pancreatic β-cell dysfunction, leading to an impaired insulin secretory response to glucose. This study aimed to determine the protective effects of sulforaphane, a natural isothiocyanate Nrf2-inducer, against cholesterol-induced pancreatic β-cells dysfunction, through molecular and cellular mechanisms involving mitochondrial bioenergetics. Sulforaphane prevented cholesterol-induced alterations in the coupling efficiency of mitochondrial respiration, improving ATP turnover and spare capacity, and averted the impairment of the electron flow at complexes I, II, and IV. Sulforaphane also attenuated the cholesterol-induced activation of the NFκB pathway, normalizing the expression of pro- and anti-inflammatory cytokines. In addition, it also inhibited the decrease in sirtuin 1 expression and greatly increased Pgc-1α expression in Min6 cells. Sulforaphane increased the expression of antioxidant enzymes downstream of the Nrf2 pathway and prevented lipid peroxidation induced by cholesterol. The antioxidant and anti-inflammatory properties of sulforaphane and its ability to protect and improve mitochondrial bioenergetic function contribute to its protective action against cholesterol-induced pancreatic β-cell dysfunction. Our data provide a scientifically tested foundation upon which sulforaphane can be developed as nutraceutical to preserve β-cell function and eventually control hyperglycemia.

  13. Mitochondrial cardiomyopathies

    Directory of Open Access Journals (Sweden)

    Ayman W. El-Hattab

    2016-07-01

    Full Text Available Mitochondria are found in all nucleated human cells and perform a variety of essential functions, including the generation of cellular energy. Mitochondria are under dual genome control. Only a small fraction of their proteins are encoded by mitochondrial DNA (mtDNA while more than 99% of them are encoded by nuclear DNA (nDNA. Mutations in mtDNA or mitochondria-related nDNA genes result in mitochondrial dysfunction leading to insufficient energy production required to meet the needs of various organs, particularly those with high energy requirements, including the central nervous system, skeletal and cardiac muscles, kidneys, liver, and endocrine system. Because cardiac muscles are one of the high energy demanding tissues, cardiac involvement occurs in mitochondrial diseases with cardiomyopathies being one of the most frequent cardiac manifestations found in these disorders. Cardiomyopathy is estimated to occur in 20-40% of children with mitochondrial diseases. Mitochondrial cardiomyopathies can vary in severity from asymptomatic status to severe manifestations including heart failure, arrhythmias, and sudden cardiac death. Hypertrophic cardiomyopathy is the most common type; however, mitochondrial cardiomyopathies might also present as dilated, restrictive, left ventricular noncompaction, and histiocytoid cardiomyopathies. Cardiomyopathies are frequent manifestations of mitochondrial diseases associated with defects in electron transport chain (ETC complexes subunits and their assembly factors, mitochondrial tRNAs, rRNAs, ribosomal proteins, and translation factors, mtDNA maintenance, and coenzyme Q10 synthesis. Other mitochondrial diseases with cardiomyopathies include Barth syndrome, Sengers syndrome, TMEM70-related mitochondrial complex V deficiency, and Friedreich ataxia.

  14. A functional test of Neandertal and modern human mitochondrial targeting sequences

    International Nuclear Information System (INIS)

    Gralle, Matthias; Schaefer, Ingo; Seibel, Peter; Paeaebo, Svante

    2010-01-01

    Research highlights: → Two mutations in mitochondrial targeting peptides occurred during human evolution, possibly after Neandertals split off from modern human lineage. → The ancestral and modern human versions of these two targeting peptides were tested functionally for their effects on localization and cleavage rate. → In spite of recent evolution, and to the contrary of other mutations in targeting peptides, these mutations had no visible effects. -- Abstract: Targeting of nuclear-encoded proteins to different organelles, such as mitochondria, is a process that can result in the redeployment of proteins to new intracellular destinations during evolution. With the sequencing of the Neandertal genome, it has become possible to identify amino acid substitutions that occurred on the modern human lineage since its separation from the Neandertal lineage. Here we analyze the function of two substitutions in mitochondrial targeting sequences that occurred and rose to high frequency recently during recent human evolution. The ancestral and modern versions of the two targeting sequences do not differ in the efficiency with which they direct a protein to the mitochondria, an observation compatible with the neutral theory of molecular evolution.

  15. Muscle endurance and mitochondrial function after chronic normobaric hypoxia: contrast of respiratory and limb muscles.

    Science.gov (United States)

    Gamboa, Jorge L; Andrade, Francisco H

    2012-02-01

    Skeletal muscle adaptation to chronic hypoxia includes loss of oxidative capacity and decrease in fiber size. However, the diaphragm may adapt differently since its activity increases in response to hypoxia. Thus, we hypothesized that chronic hypoxia would not affect endurance, mitochondrial function, or fiber size in the mouse diaphragm. Adult male mice were kept in normoxia (control) or hypoxia (hypoxia, FIO(2) = 10%) for 4 weeks. After that time, muscles were collected for histological, biochemical, and functional analyses. Hypoxia soleus muscles fatigued faster (fatigue index higher in control, 21.5 ± 2.6% vs. 13.4 ± 2.4%, p muscles, but it was 25% smaller in diaphragm (p muscles were lower: state 2 decreased 19%, state 3 31%, and state 4 18% vs. control, p muscle mitochondria had lower content of complex IV (cytochrome c oxidase), while diaphragm mitochondria had higher content of complexes IV and V (F (1)/F (0) ATP synthase) and less uncoupling protein 3 (UCP-3). These data demonstrate that diaphragm retains its endurance during chronic hypoxia, apparently due to a combination of morphometric changes and optimization of mitochondrial energy production.

  16. Mdm35p imports Ups proteins into the mitochondrial intermembrane space by functional complex formation.

    Science.gov (United States)

    Tamura, Yasushi; Iijima, Miho; Sesaki, Hiromi

    2010-09-01

    Ups1p, Ups2p, and Ups3p are three homologous proteins that control phospholipid metabolism in the mitochondrial intermembrane space (IMS). The Ups proteins are atypical IMS proteins in that they lack the two major IMS-targeting signals, bipartite presequences and cysteine motifs. Here, we show that Ups protein import is mediated by another IMS protein, Mdm35p. In vitro import assays show that import of Ups proteins requires Mdm35p. Loss of Mdm35p led to a decrease in steady state levels of Ups proteins in mitochondria. In addition, mdm35Delta cells displayed a similar phenotype to ups1Deltaups2Deltaups3Delta cells. Interestingly, unlike typical import machineries, Mdm35p associated stably with Ups proteins at a steady state after import. Demonstrating that Mdm35p is a functional component of Ups-Mdm35p complexes, restoration of Ups protein levels in mdm35Delta mitochondria failed to restore phospholipid metabolism. These findings provide a novel mechanism in which the formation of functional protein complexes drives mitochondrial protein import.

  17. A functional test of Neandertal and modern human mitochondrial targeting sequences

    Energy Technology Data Exchange (ETDEWEB)

    Gralle, Matthias, E-mail: gralle@bioqmed.ufrj.br [Instituto de Bioquimica Medica, Universidade Federal do Rio de Janeiro, CCS, Ilha do Fundao, 21941-590 Rio de Janeiro (Brazil); Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig (Germany); Schaefer, Ingo; Seibel, Peter [Department of Molecular Cell Therapy, Leipzig University, Deutscher Platz 5, 04103 Leipzig (Germany); Paeaebo, Svante [Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig (Germany)

    2010-11-26

    Research highlights: {yields} Two mutations in mitochondrial targeting peptides occurred during human evolution, possibly after Neandertals split off from modern human lineage. {yields} The ancestral and modern human versions of these two targeting peptides were tested functionally for their effects on localization and cleavage rate. {yields} In spite of recent evolution, and to the contrary of other mutations in targeting peptides, these mutations had no visible effects. -- Abstract: Targeting of nuclear-encoded proteins to different organelles, such as mitochondria, is a process that can result in the redeployment of proteins to new intracellular destinations during evolution. With the sequencing of the Neandertal genome, it has become possible to identify amino acid substitutions that occurred on the modern human lineage since its separation from the Neandertal lineage. Here we analyze the function of two substitutions in mitochondrial targeting sequences that occurred and rose to high frequency recently during recent human evolution. The ancestral and modern versions of the two targeting sequences do not differ in the efficiency with which they direct a protein to the mitochondria, an observation compatible with the neutral theory of molecular evolution.

  18. Effects of exercise training on mitochondrial function in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Larsen, Steen; Skaaby, Stinna; Helge, Jørn Wulff

    2014-01-01

    Type 2 diabetes is characterized by a decreased ability of insulin to facilitate glucose uptake into insulin sensitive tissue, i.e., skeletal muscle. The mechanism behind this is at the moment unresolved. It has been suggested that increased amount of lipids inside the skeletal muscle (intramuscu......Type 2 diabetes is characterized by a decreased ability of insulin to facilitate glucose uptake into insulin sensitive tissue, i.e., skeletal muscle. The mechanism behind this is at the moment unresolved. It has been suggested that increased amount of lipids inside the skeletal muscle...... intensity training) improves insulin sensitivity in healthy humans and in patients with type 2 diabetes. Whether patients with type 2 diabetes have the same beneficial effects (same improvement) as control subjects, when it comes to regular physical activity in regard to mitochondrial function......, is not established in the literature. This review will focus only on the effect of physical activity on skeletal muscle (mitochondrial function) in patients with type 2 diabetes....

  19. Combined effects of cadmium, temperature and hypoxia-reoxygenation on mitochondrial function in rainbow trout (Oncorhynchus mykiss)

    Energy Technology Data Exchange (ETDEWEB)

    Onukwufor, John O.; Stevens, Don; Kamunde, Collins, E-mail: ckamunde@upei.ca

    2017-01-15

    Highlights: • Ternary interactions of Cd, temperature and H-R alter their individual and binary effects on mitochondrial bioenergetics. • Oxidative stress explains many effects of Cd, H-R and temperature on mitochondria. • Cd accumulation does not explain increased sensitivity of mitochondria to multiple stressors. • Cd induces hormetic responses during H-R stress. • Cd at low dose blunts conversion of complex I active (A)- to deactive (D)-form after H-R. - Abstract: Although aquatic organisms face multiple environmental stressors that may interact to alter adverse outcomes, our knowledge of stressor–stressor interaction on cellular function is limited. We investigated the combined effects of cadmium (Cd), hypoxia-reoxygenation (H-R) and temperature on mitochondrial function. Liver mitochondria from juvenile rainbow trout were exposed to Cd (0–20 μM) and H-R (0 and 5 min) at 5, 13 and 25 °C followed by measurements of mitochondrial Cd load, volume, complex I active (A) ↔ deactive (D) transition, membrane potential, ROS release and ultrastructural changes. At high temperature Cd exacerbated H-R-imposed reduction of maximal complex I (CI) respiration whereas at low temperature 5 and 10 μM stimulated maximal CI respiration post H-R. The basal respiration showed a biphasic response at high temperatures with low Cd concentrations reducing the stimulatory effect of H-R and high concentrations enhancing this effect. At low temperature Cd monotonically enhanced H-R-induced stimulation of basal respiration. Cd and H-R reduced both the P/O ratio and the RCR at all 3 temperatures. Temperature rise alone increased mitochondrial Cd load and toxicity, but combined H-R and temperature exposure reduced mitochondrial Cd load but surprisingly exacerbated the mitochondrial dysfunction. Mitochondrial dysfunction induced by H-R was associated with swelling of the organelle and blocking of conversion of CI D to A form. However, low amounts of Cd protected against H

  20. Adaptive Linear and Normalized Combination of Radial Basis Function Networks for Function Approximation and Regression

    Directory of Open Access Journals (Sweden)

    Yunfeng Wu

    2014-01-01

    Full Text Available This paper presents a novel adaptive linear and normalized combination (ALNC method that can be used to combine the component radial basis function networks (RBFNs to implement better function approximation and regression tasks. The optimization of the fusion weights is obtained by solving a constrained quadratic programming problem. According to the instantaneous errors generated by the component RBFNs, the ALNC is able to perform the selective ensemble of multiple leaners by adaptively adjusting the fusion weights from one instance to another. The results of the experiments on eight synthetic function approximation and six benchmark regression data sets show that the ALNC method can effectively help the ensemble system achieve a higher accuracy (measured in terms of mean-squared error and the better fidelity (characterized by normalized correlation coefficient of approximation, in relation to the popular simple average, weighted average, and the Bagging methods.

  1. Human mitochondrial transcription factor A functions in both nuclei and mitochondria and regulates cancer cell growth

    International Nuclear Information System (INIS)

    Han, Bin; Izumi, Hiroto; Yasuniwa, Yoshihiro; Akiyama, Masaki; Yamaguchi, Takahiro; Fujimoto, Naohiro; Matsumoto, Tetsuro; Wu, Bin; Tanimoto, Akihide; Sasaguri, Yasuyuki; Kohno, Kimitoshi

    2011-01-01

    Highlights: → Mitochondrial transcription factor A (mtTFA) localizes in nuclei and binds tightly to the nuclear chromatin. → mtTFA contains two putative nuclear localization signals (NLS) in the HMG-boxes. → Overexpression of mtTFA enhances the growth of cancer cells, whereas downregulation of mtTFA inhibits their growth by regulating mtTFA target genes, such as baculoviral IAP repeat-containing 5 (BIRC5; also known as survivin). → Knockdown of mtTFA expression induces p21-dependent G1 cell cycle arrest. -- Abstract: Mitochondrial transcription factor A (mtTFA) is one of the high mobility group protein family and is required for both transcription from and maintenance of mitochondrial genomes. However, the roles of mtTFA have not been extensively studied in cancer cells. Here, we firstly reported the nuclear localization of mtTFA. The proportion of nuclear-localized mtTFA varied among different cancer cells. Some mtTFA binds tightly to the nuclear chromatin. DNA microarray and chromatin immunoprecipitation assays showed that mtTFA can regulate the expression of nuclear genes. Overexpression of mtTFA enhanced the growth of cancer cell lines, whereas downregulation of mtTFA inhibited their growth by regulating mtTFA target genes, such as baculoviral IAP repeat-containing 5 (BIRC5; also known as survivin). Knockdown of mtTFA expression induced p21-dependent G1 cell cycle arrest. These results imply that mtTFA functions in both nuclei and mitochondria to promote cell growth.

  2. Effects of various physical stress factors on mitochondrial function and reactive oxygen species in rat spermatozoa

    Science.gov (United States)

    Kim, Suhee; Agca, Cansu; Agca, Yuksel

    2013-01-01

    The aim of the present study was to evaluate the effects of various physical interventions on the function of epididymal rat spermatozoa and determine whether there are correlations among these functional parameters. Epididymal rat spermatozoa were subjected to various mechanical (pipetting, centrifugation and Percoll gradient separation) and anisotonic conditions, and sperm motility, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP) and intracellular reactive oxygen species (ROS) were evaluated. Repeated pipetting caused a loss in motility, PMI and MMP (P spermatozoa that were subjected to mechanical interventions showed high susceptibility to a ROS stimulant (P spermatozoa. Therefore, careful consideration and proper protocols for handling of rat spermatozoa and osmotic conditions are required to achieve reliable results and minimise damage. PMID:23140582

  3. [A preliminary study of the effect of mitochondrial autophagy on cognitive function in rats of early intermittent hypoxia].

    Science.gov (United States)

    Wang, Ling; Zhang, Panpan; Wang, Hongyang; Yu, Jiangtao; Han, Xiaoqing; Zhang, Min; Wang, Yanan; Cao, Jinli

    2014-11-01

    To explore the effect of mitochondrial autophagy on cognitive function in rats of early intermittent hypoxia by observing hippocampal CA1 pyramidal cell mitochondrial autophagy and the expression of related proteins in a intermittent hypoxia(IH) animal model. Seventy-two adult male Wistar rats were randomly divided into a control group (UC) and a 5% intermittent hypoxia (IH) group. The compressed air was given to the UC group while rats in 5% IH group suffered from 7-hour IH every day. At 1 d, 3 d, 5 d, 7 d, 10 d and 14 d after the completion of the model, transmission electron microscopy was used to observation rat hippocampal CA1 pyramidal cell mitochondrial ultrastructural changes, and immunohistochemistry assay was used to detect the expression of Beclin-1 and LC3. The Morris water test was performed to detect the learning and memory function in the rats. Compared with the UC group, the 5% IH group began to show mitochondrial size and shape changes, swelling, reduced matrix density, cristae, mitochondrial vacuolization, and typical mitochondria autophagosome formation from the 3 d. In the 5% IH group, Beclin-1 and LC3 protein expressions were significantly increased compared with the UC group (P 0.05). The level of learning and memory of the rats in the 5% IH group had no obvious changes compared with the UC group at 1 d, 3 d, 5 d, 7 d, and 10 d, but the level started to drop at 14 d with a significant difference (P memory of the rats in the UC group was not different among different time points (P > 0.05). Early intermittent hypoxia induced hippocampus mitochondrial autophagy and autophagy-related protein expression in rats. Mitochondrial autophagy may reduce the damage to cognitive function of the rats exposed to early intermittent hypoxia.

  4. Early Stress History Alters Serum Insulin-Like Growth Factor-1 and Impairs Muscle Mitochondrial Function in Adult Male Rats.

    Science.gov (United States)

    Ghosh, S; Banerjee, K K; Vaidya, V A; Kolthur-Seetharam, U

    2016-09-01

    Early-life adversity is associated with an enhanced risk for adult psychopathology. Psychiatric disorders such as depression exhibit comorbidity for metabolic dysfunction, including obesity and diabetes. However, it is poorly understood whether, besides altering anxiety and depression-like behaviour, early stress also evokes dysregulation of metabolic pathways and enhances vulnerability for metabolic disorders. We used the rodent model of the early stress of maternal separation (ES) to examine the effects of early stress on serum metabolites, insulin-like growth factor (IGF)-1 signalling, and muscle mitochondrial content. Adult ES animals exhibited dyslipidaemia, decreased serum IGF1 levels, increased expression of liver IGF binding proteins, and a decline in the expression of specific metabolic genes in the liver and muscle, including Pck1, Lpl, Pdk4 and Hmox1. These changes occurred in the absence of alterations in body weight, food intake, glucose tolerance, insulin tolerance or insulin levels. ES animals also exhibited a decline in markers of muscle mitochondrial content, such as mitochondrial DNA levels and expression of TFAM (transcription factor A, mitochondrial). Furthermore, the expression of several genes involved in mitochondrial function, such as Ppargc1a, Nrf1, Tfam, Cat, Sesn3 and Ucp3, was reduced in skeletal muscle. Adult-onset chronic unpredictable stress resulted in overlapping and distinct consequences from ES, including increased circulating triglyceride levels, and a decline in the expression of specific metabolic genes in the liver and muscle, with no change in the expression of genes involved in muscle mitochondrial function. Taken together, our results indicate that a history of early adversity can evoke persistent changes in circulating IGF-1 and muscle mitochondrial function and content, which could serve to enhance predisposition for metabolic dysfunction in adulthood. © 2016 British Society for Neuroendocrinology.

  5. Naringin Improves Neuronal Insulin Signaling, Brain Mitochondrial Function, and Cognitive Function in High-Fat Diet-Induced Obese Mice.

    Science.gov (United States)

    Wang, Dongmei; Yan, Junqiang; Chen, Jing; Wu, Wenlan; Zhu, Xiaoying; Wang, Yong

    2015-10-01

    The epidemic and experimental studies have confirmed that the obesity induced by high-fat diet not only caused neuronal insulin resistance, but also induced brain mitochondrial dysfunction as well as learning impairment in mice. Naringin has been reported to posses biological functions which are beneficial to human cognitions, but its protective effects on HFD-induced cognitive deficits and underlying mechanisms have not been well characterized. In the present study Male C57BL/6 J mice were fed either a control or high-fat diet for 20 weeks and then randomized into four groups treated with their respective diets including control diet, control diet + naringin, high-fat diet (HFD), and high-fat diet + naringin (HFDN). The behavioral performance was assessed by using novel object recognition test and Morris water maze test. Hippocampal mitochondrial parameters were analyzed. Then the protein levels of insulin signaling pathway and the AMP-activated protein kinase (AMPK) in the hippocampus were detected by Western blot method. Our results showed that oral administration of naringin significantly improved the learning and memory abilities as evidenced by increasing recognition index by 52.5% in the novel object recognition test and inducing a 1.05-fold increase in the crossing-target number in the probe test, and ameliorated mitochondrial dysfunction in mice caused by HFD consumption. Moreover, naringin significantly enhanced insulin signaling pathway as indicated by a 34.5% increase in the expression levels of IRS-1, a 47.8% decrease in the p-IRS-1, a 1.43-fold increase in the p-Akt, and a 1.89-fold increase in the p-GSK-3β in the hippocampus of the HFDN mice versus HFD mice. Furthermore, the AMPK activity significantly increased in the naringin-treated (100 mg kg(-1) d(-1)) group. These findings suggest that an enhancement in insulin signaling and a decrease in mitochondrial dysfunction through the activation of AMPK may be one of the mechanisms that naringin

  6. ROS-mediated PARP activity undermines mitochondrial function after permeability transition pore opening during myocardial ischemia-reperfusion.

    Science.gov (United States)

    Schriewer, Jacqueline M; Peek, Clara Bien; Bass, Joseph; Schumacker, Paul T

    2013-04-18

    Ischemia-reperfusion (I/R) studies have implicated oxidant stress, the mitochondrial permeability transition pore (mPTP), and poly(ADP-ribose) polymerase (PARP) as contributing factors in myocardial cell death. However, the interdependence of these factors in the intact, blood-perfused heart is not known. We therefore wanted to determine whether oxidant stress, mPTP opening, and PARP activity contribute to the same death pathway after myocardial I/R. A murine left anterior descending coronary artery (LAD) occlusion (30 minutes) and release (1 to 4 hours) model was employed. Experimental groups included controls and antioxidant-treated, mPTP-inhibited, or PARP-inhibited hearts. Antioxidant treatment prevented oxidative damage, mPTP opening, ATP depletion, and PARP activity, placing oxidant stress as the proximal death trigger. Genetic deletion of cyclophilin D (CypD(-/-)) prevented loss of total NAD(+) and PARP activity, and mPTP-mediated loss of mitochondrial function. Control hearts showed progressive mitochondrial depolarization and loss of ATP from 1.5 to 4 hours of reperfusion, but not outer mitochondrial membrane rupture. Neither genetic deletion of PARP-1 nor its pharmacological inhibition prevented the initial mPTP-mediated depolarization or loss of ATP, but PARP ablation did allow mitochondrial recovery by 4 hours of reperfusion. These results indicate that oxidant stress, the mPTP, and PARP activity contribute to a single death pathway after I/R in the heart. PARP activation undermines cell survival by preventing mitochondrial recovery after mPTP opening early in reperfusion. This suggests that PARP-mediated prolongation of mitochondrial depolarization contributes significantly to cell death via an energetic crisis rather than by mitochondrial outer membrane rupture.

  7. Normal skin and hypertrophic scar fibroblasts differentially regulate collagen and fibronectin expression as well as mitochondrial membrane potential in response to basic fibroblast growth factor.

    Science.gov (United States)

    Song, Rui; Bian, Hui-Ning; Lai, Wen; Chen, Hua-De; Zhao, Ke-Seng

    2011-05-01

    Basic fibroblast growth factor (bFGF) regulates skin wound healing; however, the underlying mechanism remains to be defined. In the present study, we determined the effects of bFGF on the regulation of cell growth as well as collagen and fibronectin expression in fibroblasts from normal human skin and from hypertrophic scars. We then explored the involvement of mitochondria in mediating bFGF-induced effects on the fibroblasts. We isolated and cultivated normal and hypertrophic scar fibroblasts from tissue biopsies of patients who underwent plastic surgery for repairing hypertrophic scars. The fibroblasts were then treated with different concentrations of bFGF (ranging from 0.1 to 1000 ng/mL). The growth of hypertrophic scar fibroblasts became slower with selective inhibition of type I collagen production after exposure to bFGF. However, type III collagen expression was affected in both normal and hypertrophic scar fibroblasts. Moreover, fibronectin expression in the normal fibroblasts was up-regulated after bFGF treatment. bFGF (1000 ng/mL) also induced mitochondrial depolarization in hypertrophic scar fibroblasts (P fibroblasts (P fibroblasts following treatment with bFGF (P fibroblasts of the normal skin and hypertrophic scars, indicating that bFGF may play a role in the early phase of skin wound healing and post-burn scar formation.

  8. Insulin Resistance Is Not Associated with an Impaired Mitochondrial Function in Contracting Gastrocnemius Muscle of Goto-Kakizaki Diabetic Rats In Vivo.

    Directory of Open Access Journals (Sweden)

    Michael Macia

    Full Text Available Insulin resistance, altered lipid metabolism and mitochondrial dysfunction in skeletal muscle would play a major role in type 2 diabetes mellitus (T2DM development, but the causal relationships between these events remain conflicting. To clarify this issue, gastrocnemius muscle function and energetics were investigated throughout a multidisciplinary approach combining in vivo and in vitro measurements in Goto-Kakizaki (GK rats, a non-obese T2DM model developing peripheral insulin resistant without abnormal level of plasma non-esterified fatty acids (NEFA. Wistar rats were used as controls. Mechanical performance and energy metabolism were assessed strictly non-invasively using magnetic resonance (MR imaging and 31-phosphorus MR spectroscopy (31P-MRS. Compared with control group, plasma insulin and glucose were respectively lower and higher in GK rats, but plasma NEFA level was normal. In resting GK muscle, phosphocreatine content was reduced whereas glucose content and intracellular pH were both higher. However, there were not differences between both groups for basal oxidative ATP synthesis rate, citrate synthase activity, and intramyocellular contents for lipids, glycogen, ATP and ADP (an important in vivo mitochondrial regulator. During a standardized fatiguing protocol (6 min of maximal repeated isometric contractions electrically induced at a frequency of 1.7 Hz, mechanical performance and glycolytic ATP production rate were reduced in diabetic animals whereas oxidative ATP production rate, maximal mitochondrial capacity and ATP cost of contraction were not changed. These findings provide in vivo evidence that insulin resistance is not caused by an impairment of mitochondrial function in this diabetic model.

  9. How AMPK and PKA Interplay to Regulate Mitochondrial Function and Survival in Models of Ischemia and Diabetes

    Directory of Open Access Journals (Sweden)

    Jingdian Zhang

    2017-01-01

    Full Text Available Adenosine monophosphate-activated protein kinase (AMPK is a conserved, redox-activated master regulator of cell metabolism. In the presence of oxidative stress, AMPK promotes cytoprotection by enhancing the conservation of energy by suppressing protein translation and by stimulating autophagy. AMPK interplays with protein kinase A (PKA to regulate oxidative stress, mitochondrial function, and cell survival. AMPK and dual-specificity A-kinase anchoring protein 1 (D-AKAP1, a mitochondrial-directed scaffold of PKA, interact to regulate mitochondrial function and oxidative stress in cardiac and endothelial cells. Ischemia and diabetes, a chronic disease that increases the onset of cardiovascular diseases, suppress the cardioprotective effects of AMPK and PKA. Here, we review the molecular mechanisms by which AMPK and D-AKAP1/PKA interplay to regulate mitochondrial function, oxidative stress, and signaling pathways that prime endothelial cells, cardiac cells, and neurons for cytoprotection against oxidative stress. We discuss recent literature showing how temporal dynamics and localization of activated AMPK and PKA holoenzymes play a crucial role in governing cellular bioenergetics and cell survival in models of ischemia, cardiovascular diseases, and diabetes. Finally, we propose therapeutic strategies that tout localized PKA and AMPK signaling to reverse mitochondrial dysfunction, oxidative stress, and death of neurons and cardiac and endothelial cells during ischemia and diabetes.

  10. Unacylated ghrelin does not alter mitochondrial function, redox state and triglyceride content in rat liver in vivo

    Directory of Open Access Journals (Sweden)

    Gianluca Gortan Cappellari

    2015-12-01

    Full Text Available Changes in liver mitochondrial function with more oxidized redox state and enhanced inflammation may contribute to the onset of obesity- and insulin resistance-associated hepatic complications, including non-alcoholic fatty liver disease and steato-hepatitis. Unacylated ghrelin (UnAG is a gastric hormone reported to be associated with lower oxidative stress in different cell types, but its potential effects on liver mitochondrial function, redox state and inflammation in vivo remains undetermined. We investigated the impact of chronic UnAG overexpression (Tg Myh6/Ghrl leading to systemic upregulation of circulating hormone on mitochondrial ATP production, redox state (oxidized-to-total glutathione and inflammation markers in lean mice. Compared to wild-type animals (wt, Tg Myh6/Ghrl had superimposable liver weight, triglyceride content and plasma lipid profile. Liver mitochondrial enzyme activities and ATP production as well as oxidized-to-total glutathione were also similar in the two groups. In addition, no differences were observed in tissue inflammation marker TNF-alpha between wild-type and Tg Myh6/Ghrl animals. Thus, chronic systemic UnAG upregulation does not alter liver triglyceride content, mitochondrial function, redox state and inflammation markers in lean mice. These findings do not support a major role of UnAG as a physiological modulator of in vivo liver oxidative-lipid metabolism and inflammation.

  11. Progress in understanding the molecular oxygen paradox - function of mitochondrial reactive oxygen species in cell signaling.

    Science.gov (United States)

    Kuksal, Nidhi; Chalker, Julia; Mailloux, Ryan J

    2017-10-26

    The molecular oxygen (O2) paradox was coined to describe its essential nature and toxicity. The latter characteristic of O2 is associated with the formation of reactive oxygen species (ROS), which can damage structures vital for cellular function. Mammals are equipped with antioxidant systems to fend off the potentially damaging effects of ROS. However, under certain circumstances antioxidant systems can become overwhelmed leading to oxidative stress and damage. Over the past few decades, it has become evident that ROS, specifically H2O2, are integral signaling molecules complicating the previous logos that oxyradicals were unfortunate by-products of oxygen metabolism that indiscriminately damage cell structures. To avoid its potential toxicity whilst taking advantage of its signaling properties, it is vital for mitochondria to control ROS production and degradation. H2O2 elimination pathways are well characterized in mitochondria. However, less is known about how H2O2 production is controlled. The present review examines the importance of mitochondrial H2O2 in controlling various cellular programs and emerging evidence for how production is regulated. Recently published studies showing how mitochondrial H2O2 can be used as a secondary messenger will be discussed in detail. This will be followed with a description of how mitochondria use S-glutathionylation to control H2O2 production.

  12. Effects of chitosan and oligochitosan on development and mitochondrial function of Rhizopus stolonifer.

    Science.gov (United States)

    Robles-Martínez, Leobarda; Guerra-Sánchez, María Guadalupe; Hernández-Lauzardo, Ana Niurka; Pardo, Juan Pablo; Velázquez-del Valle, Miguel Gerardo

    2014-07-01

    The antifungal activities of chitosan and oligochitosan have been used to control postharvest decay of the fruits. The effect of chitosan and oligochitosan on mycelium growth, spore germination, and mitochondrial function of Rhizopus stolonifer was evaluated in order to establish a connection between fungus development and the main organelle in charge to provide energy to the cell. The mycelium growth of R. stolonifer was significantly reduced on minimum media amended with chitosan or oligochitosan. The highest antifungal indexes were obtained on media containing chitosan or oligochitosan at 2.0 mg ml(-1). Microscopic observation showed that chitosan and oligochitosan affected the spore germination and hyphae morphology. Both polymers increased oxygen consumption of R. stolonifer. Respiratory activity was restored with NADH in permeabilized treated and untreated cells, and was inhibited with rotenone and flavones. Complex III and IV were inhibited by antimycin A and cyanide, respectively, in treated and untreated cells. Chitosan and oligochitosan increased NADH dehydrogenase activity in isolated mitochondria. However, there were not changes in the cytochrome c oxidase and ATPase activities by effect of these polymers. These results suggest that both chitosan and oligochitosan affect the development of R. stolonifer and might be implicated in the mitochondrial dysfunction. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Functional characterization of the Drosophila MRP (mitochondrial RNA processing) RNA gene.

    Science.gov (United States)

    Schneider, Mary D; Bains, Anupinder K; Rajendra, T K; Dominski, Zbigniew; Matera, A Gregory; Simmonds, Andrew J

    2010-11-01

    MRP RNA is a noncoding RNA component of RNase mitochondrial RNA processing (MRP), a multi-protein eukaryotic endoribonuclease reported to function in multiple cellular processes, including ribosomal RNA processing, mitochondrial DNA replication, and cell cycle regulation. A recent study predicted a potential Drosophila ortholog of MRP RNA (CR33682) by computer-based genome analysis. We have confirmed the expression of this gene and characterized the phenotype associated with this locus. Flies with mutations that specifically affect MRP RNA show defects in growth and development that begin in the early larval period and end in larval death during the second instar stage. We present several lines of evidence demonstrating a role for Drosophila MRP RNA in rRNA processing. The nuclear fraction of Drosophila MRP RNA localizes to the nucleolus. Further, a mutant strain shows defects in rRNA processing that include a defect in 5.8S rRNA processing, typical of MRP RNA mutants in other species, as well as defects in early stages of rRNA processing.

  14. Exercise training protects against aging-induced mitochondrial fragmentation in mouse skeletal muscle in a PGC-1α dependent manner

    DEFF Research Database (Denmark)

    Halling, Jens Frey; Jørgensen, Stine Ringholm; Olesen, Jesper

    2017-01-01

    Aging is associated with impaired mitochondrial function, whereas exercise training enhances mitochondrial content and function in part through activation of PGC-1α. Mitochondria form dynamic networks regulated by fission and fusion with profound effects on mitochondrial functions, yet the effects...... of aging and exercise training on mitochondrial network structure remain unclear. This study examined the effects of aging and exercise training on mitochondrial network structure using confocal microscopy on mitochondria-specific stains in single muscle fibers from PGC-1α KO and WT mice....... Hyperfragmentation of mitochondrial networks was observed in aged relative to young animals while exercise training normalized mitochondrial network structure in WT, but not in PGC-1α KO. Mitochondrial fission protein content (FIS1 and DRP1) relative to mitochondrial content was increased with aging in both WT...

  15. Ancestral sequence reconstruction in primate mitochondrial DNA: compositional bias and effect on functional inference.

    Science.gov (United States)

    Krishnan, Neeraja M; Seligmann, Hervé; Stewart, Caro-Beth; De Koning, A P Jason; Pollock, David D

    2004-10-01

    Reconstruction of ancestral DNA and amino acid sequences is an important means of inferring information about past evolutionary events. Such reconstructions suggest changes in molecular function and evolutionary processes over the course of evolution and are used to infer adaptation and convergence. Maximum likelihood (ML) is generally thought to provide relatively accurate reconstructed sequences compared to parsimony, but both methods lead to the inference of multiple directional changes in nucleotide frequencies in primate mitochondrial DNA (mtDNA). To better understand this surprising result, as well as to better understand how parsimony and ML differ, we constructed a series of computationally simple "conditional pathway" methods that differed in the number of substitutions allowed per site along each branch, and we also evaluated the entire Bayesian posterior frequency distribution of reconstructed ancestral states. We analyzed primate mitochondrial cytochrome b (Cyt-b) and cytochrome oxidase subunit I (COI) genes and found that ML reconstructs ancestral frequencies that are often more different from tip sequences than are parsimony reconstructions. In contrast, frequency reconstructions based on the posterior ensemble more closely resemble extant nucleotide frequencies. Simulations indicate that these differences in ancestral sequence inference are probably due to deterministic bias caused by high uncertainty in the optimization-based ancestral reconstruction methods (parsimony, ML, Bayesian maximum a posteriori). In contrast, ancestral nucleotide frequencies based on an average of the Bayesian set of credible ancestral sequences are much less biased. The methods involving simpler conditional pathway calculations have slightly reduced likelihood values compared to full likelihood calculations, but they can provide fairly unbiased nucleotide reconstructions and may be useful in more complex phylogenetic analyses than considered here due to their speed and

  16. Neuronal function in male Sprague Dawley rats during normal ageing

    African Journals Online (AJOL)

    During normal ageing, there are physiological changes especially in high energy demanding tissues including the brain and skeletal muscles. Ageing may disrupt homeostasis and allow tissue vulnerability to disease. To establish an appropriate animal model which is readily available and will be useful to test therapeutic ...

  17. Normal mitochondrial function and increased fat oxidation capacity in leg and arm muscles in obese humans

    DEFF Research Database (Denmark)

    Ara, I; Larsen, S; Stallknecht, Bente Merete

    2011-01-01

    was that fat oxidation during exercise might be differentially preserved in leg and arm muscles after weight loss.Methods:Indirect calorimetry was used to calculate fat and carbohydrate oxidation during both progressive arm-cranking and leg-cycling exercises. Muscle biopsy samples were obtained from musculus......, and plasma leptin was higher in O than in PO and C.Conclusions:In O subjects, maximal fat oxidation during exercise and the eliciting relative exercise intensity are increased. This is associated with higher intramuscular triglyceride levels and higher resting non esterified fatty acid (NEFA) concentrations...... deltoideus (m. deltoideus) and m. vastus lateralis muscles. Fibre-type composition, enzyme activity and O(2) flux capacity of saponin-permeabilized muscle fibres were measured, the latter by high-resolution respirometry.Results:During the graded exercise tests, peak fat oxidation during leg cycling...

  18. Dual functions of α-ketoglutarate dehydrogenase E2 in the Krebs cycle and mitochondrial DNA inheritance in Trypanosoma brucei.

    Science.gov (United States)

    Sykes, Steven E; Hajduk, Stephen L

    2013-01-01

    The dihydrolipoyl succinyltransferase (E2) of the multisubunit α-ketoglutarate dehydrogenase complex (α-KD) is an essential Krebs cycle enzyme commonly found in the matrices of mitochondria. African trypanosomes developmentally regulate mitochondrial carbohydrate metabolism and lack a functional Krebs cycle in the bloodstream of mammals. We found that despite the absence of a functional α-KD, bloodstream form (BF) trypanosomes express α-KDE2, which localized to the mitochondrial matrix and inner membrane. Furthermore, α-KDE2 fractionated with the mitochondrial genome, the kinetoplast DNA (kDNA), in a complex with the flagellum. A role for α-KDE2 in kDNA maintenance was revealed in α-KDE2 RNA interference (RNAi) knockdowns. Following RNAi induction, bloodstream trypanosomes showed pronounced growth reduction and often failed to equally distribute kDNA to daughter cells, resulting in accumulation of cells devoid of kDNA (dyskinetoplastic) or containing two kinetoplasts. Dyskinetoplastic trypanosomes lacked mitochondrial membrane potential and contained mitochondria of substantially reduced volume. These results indicate that α-KDE2 is bifunctional, both as a metabolic enzyme and as a mitochondrial inheritance factor necessary for the distribution of kDNA networks to daughter cells at cytokinesis.

  19. The neuroprotective effects of taurine against nickel by reducing oxidative stress and maintaining mitochondrial function in cortical neurons.

    Science.gov (United States)

    Xu, Shangcheng; He, Mindi; Zhong, Min; Li, Li; Lu, Yonghui; Zhang, Yanwen; Zhang, Lei; Yu, Zhengping; Zhou, Zhou

    2015-03-17

    Previous studies have indicated that oxidative stress and mitochondrial dysfunction are involved in the toxicity of nickel. Taurine is recognized as an efficient antioxidant and is essential for mitochondrial function. To investigate whether taurine could protect against the neurotoxicity of nickel, we exposed primary cultured cortical neurons to various concentrations of nickel chloride (NiCl2; 0.5mM, 1mM and 2mM) for 24h or to 1mM NiCl2 for various periods (0 h, 12h, 24h and 48 h). Our results showed that taurine efficiently reduced lactate dehydrogenase (LDH) release induced by NiCl2. Along with this protective effect, taurine pretreatment not only significantly reversed the increase of ROS production and mitochondrial superoxide concentration, but also attenuated the decrease of superoxide dismutase (SOD) activity and glutathione (GSH) concentration in neurons exposed to NiCl2 for 24h. Moreover, nickel exposure reduced ATP production, disrupted the mitochondrial membrane potential and decreased mtDNA content. These types of oxidative damage in the mitochondria were efficiently ameliorated by taurine pretreatment. Taken together, our results indicate that the neuroprotective effects of taurine against the toxicity of nickel might largely depend on its roles in reducing oxidative stress and improving mitochondrial function. Taurine may have great pharmacological potential in treating the adverse effects of nickel in the nervous system. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. DNM1L Variant Alters Baseline Mitochondrial Function and Response to Stress in a Patient with Severe Neurological Dysfunction.

    Science.gov (United States)

    Hogarth, Kaley A; Costford, Sheila R; Yoon, Grace; Sondheimer, Neal; Maynes, Jason T

    2018-04-01

    Mitochondria play vital roles in brain development and neuronal activity, and mitochondrial dynamics (fission and fusion) maintain organelle function through the removal of damaged components. Dynamin-like protein-1 (DRP-1), encoded by DNM1L, is an evolutionarily conserved GTPase that mediates mitochondrial fission by surrounding the scission site in concentric ring-like structures via self-oligomerization, followed by GTPase-dependant constriction. Here, we describe the clinical characteristics and cellular phenotype of a patient with severe neurological dysfunction, possessing a homozygous DNM1L variant c.305C>T (p.T115M) in the GTPase domain. For comparative analysis, we also describe a previously identified heterozygous variant demonstrating a rapidly fatal neurocognitive phenotype (c.261dup/c.385:386del, p.W88M*9/E129K*6). Using patient-generated fibroblasts, we demonstrated both DNM1L variants undergo adverse alterations to mitochondrial structure and function, including impaired mitochondrial fission, reduced membrane potential, and lower oxidative capacity including an increased cellular level of reactive oxygen species (ROS) and dsDNA breaks. Mutation of DNM1L was also associated with impaired responses to oxidative stress, as treatment with hydrogen peroxide dramatically increased cellular ROS, with minimal exacerbation of already impaired mitochondrial function. Taken together, our observations indicate that homozygous p.T115M variant of DNM1L produces a neurological and neurodevelopmental phenotype, consistent with impaired mitochondrial architecture and function, through a diminished ability to oligomerize, which was most prevalent under oxidative stress.

  1. Decreased in vitro mitochondrial function is associated with enhanced brain metabolism, blood flow, and memory in Surf1-deficient mice.

    Science.gov (United States)

    Lin, Ai-Ling; Pulliam, Daniel A; Deepa, Sathyaseelan S; Halloran, Jonathan J; Hussong, Stacy A; Burbank, Raquel R; Bresnen, Andrew; Liu, Yuhong; Podlutskaya, Natalia; Soundararajan, Anuradha; Muir, Eric; Duong, Timothy Q; Bokov, Alex F; Viscomi, Carlo; Zeviani, Massimo; Richardson, Arlan G; Van Remmen, Holly; Fox, Peter T; Galvan, Veronica

    2013-10-01

    Recent studies have challenged the prevailing view that reduced mitochondrial function and increased oxidative stress are correlated with reduced longevity. Mice carrying a homozygous knockout (KO) of the Surf1 gene showed a significant decrease in mitochondrial electron transport chain Complex IV activity, yet displayed increased lifespan and reduced brain damage after excitotoxic insults. In the present study, we examined brain metabolism, brain hemodynamics, and memory of Surf1 KO mice using in vitro measures of mitochondrial function, in vivo neuroimaging, and behavioral testing. We show that decreased respiration and increased generation of hydrogen peroxide in isolated Surf1 KO brain mitochondria are associated with increased brain glucose metabolism, cerebral blood flow, and lactate levels, and with enhanced memory in Surf1 KO mice. These metabolic and functional changes in Surf1 KO brains were accompanied by higher levels of hypoxia-inducible factor 1 alpha, and by increases in the activated form of cyclic AMP response element-binding factor, which is integral to memory formation. These findings suggest that Surf1 deficiency-induced metabolic alterations may have positive effects on brain function. Exploring the relationship between mitochondrial activity, oxidative stress, and brain function will enhance our understanding of cognitive aging and of age-related neurologic disorders.

  2. Roles of Pyruvate, NADH, and Mitochondrial Complex I in Redox Balance and Imbalance in β Cell Function and Dysfunction

    Directory of Open Access Journals (Sweden)

    Xiaoting Luo

    2015-01-01

    Full Text Available Pancreatic β cells not only use glucose as an energy source, but also sense blood glucose levels for insulin secretion. While pyruvate and NADH metabolic pathways are known to be involved in regulating insulin secretion in response to glucose stimulation, the roles of many other components along the metabolic pathways remain poorly understood. Such is the case for mitochondrial complex I (NADH/ubiquinone oxidoreductase. It is known that normal complex I function is absolutely required for episodic insulin secretion after a meal, but the role of complex I in β cells in the diabetic pancreas remains to be investigated. In this paper, we review the roles of pyruvate, NADH, and complex I in insulin secretion and hypothesize that complex I plays a crucial role in the pathogenesis of β cell dysfunction in the diabetic pancreas. This hypothesis is based on the establishment that chronic hyperglycemia overloads complex I with NADH leading to enhanced complex I production of reactive oxygen species. As nearly all metabolic pathways are impaired in diabetes, understanding how complex I in the β cells copes with elevated levels of NADH in the diabetic pancreas may provide potential therapeutic strategies for diabetes.

  3. MLN64 induces mitochondrial dysfunction associated with increased mitochondrial cholesterol content

    Directory of Open Access Journals (Sweden)

    Elisa Balboa

    2017-08-01

    Full Text Available MLN64 is a late endosomal cholesterol-binding membrane protein that has been implicated in cholesterol transport from endosomal membranes to the plasma membrane and/or mitochondria, in toxin-induced resistance, and in mitochondrial dysfunction. Down-regulation of MLN64 in Niemann-Pick C1 deficient cells decreased mitochondrial cholesterol content, suggesting that MLN64 functions independently of NPC1. However, the role of MLN64 in the maintenance of endosomal cholesterol flow and intracellular cholesterol homeostasis remains unclear. We have previously described that hepatic MLN64 overexpression increases liver cholesterol content and induces liver damage. Here, we studied the function of MLN64 in normal and NPC1-deficient cells and we evaluated whether MLN64 overexpressing cells exhibit alterations in mitochondrial function. We used recombinant-adenovirus-mediated MLN64 gene transfer to overexpress MLN64 in mouse liver and hepatic cells; and RNA interference to down-regulate MLN64 in NPC1-deficient cells. In MLN64-overexpressing cells, we found increased mitochondrial cholesterol content and decreased glutathione (GSH levels and ATPase activity. Furthermore, we found decreased mitochondrial membrane potential and mitochondrial fragmentation and increased mitochondrial superoxide levels in MLN64-overexpressing cells and in NPC1-deficient cells. Consequently, MLN64 expression was increased in NPC1-deficient cells and reduction of its expression restore mitochondrial membrane potential and mitochondrial superoxide levels. Our findings suggest that MLN64 overexpression induces an increase in mitochondrial cholesterol content and consequently a decrease in mitochondrial GSH content leading to mitochondrial dysfunction. In addition, we demonstrate that MLN64 expression is increased in NPC cells and plays a key role in cholesterol transport into the mitochondria.

  4. MLN64 induces mitochondrial dysfunction associated with increased mitochondrial cholesterol content.

    Science.gov (United States)

    Balboa, Elisa; Castro, Juan; Pinochet, María-José; Cancino, Gonzalo I; Matías, Nuria; Sáez, P J; Martínez, Alexis; Álvarez, Alejandra R; Garcia-Ruiz, Carmen; Fernandez-Checa, José C; Zanlungo, Silvana

    2017-08-01

    MLN64 is a late endosomal cholesterol-binding membrane protein that has been implicated in cholesterol transport from endosomal membranes to the plasma membrane and/or mitochondria, in toxin-induced resistance, and in mitochondrial dysfunction. Down-regulation of MLN64 in Niemann-Pick C1 deficient cells decreased mitochondrial cholesterol content, suggesting that MLN64 functions independently of NPC1. However, the role of MLN64 in the maintenance of endosomal cholesterol flow and intracellular cholesterol homeostasis remains unclear. We have previously described that hepatic MLN64 overexpression increases liver cholesterol content and induces liver damage. Here, we studied the function of MLN64 in normal and NPC1-deficient cells and we evaluated whether MLN64 overexpressing cells exhibit alterations in mitochondrial function. We used recombinant-adenovirus-mediated MLN64 gene transfer to overexpress MLN64 in mouse liver and hepatic cells; and RNA interference to down-regulate MLN64 in NPC1-deficient cells. In MLN64-overexpressing cells, we found increased mitochondrial cholesterol content and decreased glutathione (GSH) levels and ATPase activity. Furthermore, we found decreased mitochondrial membrane potential and mitochondrial fragmentation and increased mitochondrial superoxide levels in MLN64-overexpressing cells and in NPC1-deficient cells. Consequently, MLN64 expression was increased in NPC1-deficient cells and reduction of its expression restore mitochondrial membrane potential and mitochondrial superoxide levels. Our findings suggest that MLN64 overexpression induces an increase in mitochondrial cholesterol content and consequently a decrease in mitochondrial GSH content leading to mitochondrial dysfunction. In addition, we demonstrate that MLN64 expression is increased in NPC cells and plays a key role in cholesterol transport into the mitochondria. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  5. MoDnm1 Dynamin Mediating Peroxisomal and Mitochondrial Fission in Complex with MoFis1 and MoMdv1 Is Important for Development of Functional Appressorium in Magnaporthe oryzae.

    Directory of Open Access Journals (Sweden)

    Kaili Zhong

    2016-08-01

    Full Text Available Dynamins are large superfamily GTPase proteins that are involved in various cellular processes including budding of transport vesicles, division of organelles, cytokinesis, and pathogen resistance. Here, we characterized several dynamin-related proteins from the rice blast fungus Magnaporthe oryzae and found that MoDnm1 is required for normal functions, including vegetative growth, conidiogenesis, and full pathogenicity. In addition, we found that MoDnm1 co-localizes with peroxisomes and mitochondria, which is consistent with the conserved role of dynamin proteins. Importantly, MoDnm1-dependent peroxisomal and mitochondrial fission involves functions of mitochondrial fission protein MoFis1 and WD-40 repeat protein MoMdv1. These two proteins display similar cellular functions and subcellular localizations as MoDnm1, and are also required for full pathogenicity. Further studies showed that MoDnm1, MoFis1 and MoMdv1 are in complex to regulate not only peroxisomal and mitochondrial fission, pexophagy and mitophagy progression, but also appressorium function and host penetration. In summary, our studies provide new insights into how MoDnm1 interacts with its partner proteins to mediate peroxisomal and mitochondrial functions and how such regulatory events may link to differentiation and pathogenicity in the rice blast fungus.

  6. Nonischemic changes in right ventricular function on exercise. Do normal volunteers differ from patients with normal coronary arteries

    International Nuclear Information System (INIS)

    Caplin, J.L.; Maltz, M.B.; Flatman, W.D.; Dymond, D.S.

    1988-01-01

    Factors other than ischemia may alter right ventricular function both at rest and on exercise. Normal volunteers differ from cardiac patients with normal coronary arteries with regard to their left ventricular response to exercise. This study examined changes in right ventricular function on exercise in 21 normal volunteers and 13 patients with normal coronary arteries, using first-pass radionuclide angiography. There were large ranges of right ventricular ejection fraction in the two groups, both at rest and on exercise. Resting right ventricular ejection fraction was 40.2 +/- 10.6% (mean +/- SD) in the volunteers and 38.6 +/- 9.7% in the patients, p = not significant, and on exercise rose significantly in both groups to 46.1 +/- 9.9% and 45.8 +/- 9.7%, respectively. The difference between the groups was not significant. In both groups some subjects with high resting values showed large decreases in ejection fraction on exercise, and there were significant negative correlations between resting ejection fraction and the change on exercise, r = -0.59 (p less than 0.01) in volunteers, and r = -0.66 (p less than 0.05) in patients. Older volunteers tended to have lower rest and exercise ejection fractions, but there was no difference between normotensive and hypertensive patients in their rest or exercise values. In conclusion, changes in right ventricular function on exercise are similar in normal volunteers and in patients with normal coronary arteries. Some subjects show decreases in right ventricular ejection fraction on exercise which do not appear to be related to ischemia

  7. Short-term increase of plasma free fatty acids does not interfere with intrinsic mitochondrial function in healthy young men

    NARCIS (Netherlands)

    Brands, Myrte; Hoeks, Joris; Sauerwein, Hans P.; Ackermans, Mariette T.; Ouwens, Margriet; Lammers, Nicolette M.; van der Plas, Mart N.; Schrauwen, Patrick; Groen, Albert K.; Serlie, Mireille J.

    2011-01-01

    Free fatty acid (FFA)- and obesity-induced insulin resistance has been associated with disturbed mitochondrial function. Elevated plasma FFA can impair insulin-induced increase of adenosine triphosphate synthesis and downregulate the expression of genes important in the biogenesis of mitochondria in

  8. A short period of high-intensity interval training improves skeletal muscle mitochondrial function and pulmonary oxygen uptake kinetics

    DEFF Research Database (Denmark)

    Christensen, Peter Møller; Jacobs, Robert A; Bonne, Thomas Christian

    2016-01-01

    The aim of the present study was to examine whether improvements in pulmonary V̇O2 kinetics following a short period of high-intensity training (HIT) would be associated with improved skeletal muscle mitochondrial function. Ten untrained male volunteers (age: 26 ± 2; mean ± SD) performed six HIT ...

  9. Preserved cardiac mitochondrial function and reduced ischaemia/reperfusion injury afforded by chronic continuous hypoxia: Role of opioid receptors

    Czech Academy of Sciences Publication Activity Database

    Maslov, L. N.; Naryzhnaya, N. V.; Prokudina, E. S.; Kolář, František; Gorbunov, A. S.; Zhang, Y.; Wang, H.; Tsibulnikov, S.Yu.; Portnichenko, A. G.; Lasukova, T. V.; Lishmanov, Yu. B.

    2015-01-01

    Roč. 42, č. 5 (2015), s. 496-501 ISSN 1440-1681 R&D Projects: GA ČR(CZ) GAP303/12/1162 Institutional support: RVO:67985823 Keywords : cardioprotection * chronic hypoxia * ischaemia/reperfusion * mitochondrial function * opioid receptors Subject RIV: ED - Physiology Impact factor: 2.004, year: 2015

  10. High-confidence assessment of functional impact of human mitochondrial non-synonymous genome variations by APOGEE.

    Directory of Open Access Journals (Sweden)

    Stefano Castellana

    2017-06-01

    Full Text Available 24,189 are all the possible non-synonymous amino acid changes potentially affecting the human mitochondrial DNA. Only a tiny subset was functionally evaluated with certainty so far, while the pathogenicity of the vast majority was only assessed in-silico by software predictors. Since these tools proved to be rather incongruent, we have designed and implemented APOGEE, a machine-learning algorithm that outperforms all existing prediction methods in estimating the harmfulness of mitochondrial non-synonymous genome variations. We provide a detailed description of the underlying algorithm, of the selected and manually curated training and test sets of variants, as well as of its classification ability.

  11. Intensive insulin therapy improves insulin sensitivity and mitochondrial function in severely burned children.

    Science.gov (United States)

    Fram, Ricki Y; Cree, Melanie G; Wolfe, Robert R; Mlcak, Ronald P; Qian, Ting; Chinkes, David L; Herndon, David N

    2010-06-01

    To institute intensive insulin therapy protocol in an acute pediatric burn unit and study the mechanisms underlying its benefits. Prospective, randomized study. An acute pediatric burn unit in a tertiary teaching hospital. Children, 4-18 yrs old, with total body surface area burned > or =40% and who arrived within 1 wk after injury were enrolled in the study. Patients were randomized to one of two groups. Intensive insulin therapy maintained blood glucose levels between 80 and 110 mg/dL. Conventional insulin therapy maintained blood glucose < or =215 mg/dL. Twenty patients were included in the data analysis consisting of resting energy expenditure, whole body and liver insulin sensitivity, and skeletal muscle mitochondrial function. Studies were performed at 7 days postburn (pretreatment) and at 21 days postburn (posttreatment). Resting energy expenditure significantly increased posttreatment (1476 +/- 124 to 1925 +/- 291 kcal/m(2) x day; p = .02) in conventional insulin therapy as compared with a decline in intensive insulin therapy. Glucose infusion rate was identical between groups before treatment (6.0 +/- 0.8 conventional insulin therapy vs. 6.8 +/- 0.9 mg/kg x min intensive insulin therapy; p = .5). Intensive insulin therapy displayed a significantly higher glucose clamp infusion rate posttreatment (9.1 +/- 1.3 intensive insulin therapy versus 4.8 +/- 0.6 mg/kg x min conventional insulin therapy, p = .005). Suppression of hepatic glucose release was significantly greater in the intensive insulin therapy after treatment compared with conventional insulin therapy (5.0 +/- 0.9 vs. 2.5 +/- 0.6 mg/kg x min; intensive insulin therapy vs. conventional insulin therapy; p = .03). States 3 and 4 mitochondrial oxidation of palmitate significantly improved in intensive insulin therapy (0.9 +/- 0.1 to 1.7 +/- 0.1 microm O(2)/CS/mg protein/min for state 3, p = .004; and 0.7 +/- 0.1 to 1.3 +/- 0.1 microm O(2)/CS/mg protein/min for state 4, p < .002), whereas conventional

  12. Mitochondrial Function, Dynamics, and Permeability Transition: A Complex Love Triangle as A Possible Target for the Treatment of Brain Aging and Alzheimer's Disease.

    Science.gov (United States)

    Stockburger, Carola; Eckert, Schamim; Eckert, Gunter P; Friedland-Leuner, Kristina; Müller, Walter E

    2018-02-28

    Because of the failure of all amyloid-β directed treatment strategies for Alzheimer's disease (AD), the concept of mitochondrial dysfunction as a major pathomechanism of the cognitive decline in aging and AD has received substantial support. Accordingly, improving mitochondrial function as an alternative strategy for new drug development became of increasing interest and many different compounds have been identified which improve mitochondrial function in preclinical in vitro and in vivo experiments. However, very few if any have been investigated in clinical trials, representing a major drawback of the mitochondria directed drug development. To overcome these problems, we used a top-down approach by investigating several older antidementia drugs with clinical evidence of therapeutic efficacy. These include EGb761® (standardized ginkgo biloba extract), piracetam, and Dimebon. All improve experimentally many aspects of mitochondrial dysfunction including mitochondrial dynamics and also improve cognition and impaired neuronal plasticity, the functionally most relevant consequences of mitochondrial dysfunction. All partially inhibit opening events of the mitochondrial permeability transition pore (mPTP) which previously has mainly been discussed as a mechanism relevant for the induction of apoptosis. However, as more recent work suggests, the mPTP as a master regulator of many mitochondrial functions, our data suggest the mPTP as a possible relevant drug target within the love triangle between mPTP regulation, mitochondrial dynamics, and mitochondrial function including regulation of neuronal plasticity. Drugs interfering with mPTP function will improve not only mitochondrial impairment in aging and AD but also will have beneficial effects on impaired neuronal plasticity, the pathomechanism which correlates best with functional deficits (cognition, behavior) in aging and AD.

  13. Improved mitochondrial function in brain aging and Alzheimer disease - the new mechanism of action of the old metabolic enhancer piracetam

    Directory of Open Access Journals (Sweden)

    Kristina Leuner

    2010-09-01

    Full Text Available Piracetam, the prototype of the so-called nootropic drugs’ is used since many years in different countries to treat cognitive impairment in aging and dementia. Findings that piracetam enhances fluidity of brain mitochondrial membranes led to the hypothesis that piracetam might improve mitochondrial function, e.g. might enhance ATP synthesis. This assumption has recently been supported by a number of observations showing enhanced mitochondrial membrane potential (MMP, enhanced ATP production, and reduced sensitivity for apoptosis in a variety of cell and animal models for aging and Alzheimer disease (AD. As a specific consequence, substantial evidence for elevated neuronal plasticity as a specific effect of piracetam has emerged. Taken together, these new findings can explain many of the therapeutic effects of piracetam on cognition in aging and dementia as well as different situations of brain dysfunctions.

  14. The physiological significance of a coronary stenosis differentially affects contractility and mitochondrial function in viable chronically dysfunctional myocardium.

    Science.gov (United States)

    Page, Brian J; Young, Rebeccah F; Suzuki, Gen; Fallavollita, James A; Canty, John M

    2013-07-01

    The reversibility of viable dysfunctional myocardium after revascularization is variable and the reasons for this are unknown. Using 2D-DIGE, we tested the hypothesis that this could reflect the extent of molecular remodeling of myocardial tissue in the absence of infarction. Swine with a progressive left anterior descending (LAD) stenosis were studied 2 months (n = 18) or 3 months (n = 22) post-instrumentation. Coronary flow reserve (vasodilated/rest) was severely reduced at 2 months (LAD 2.6 ± 0.4 versus 5.1 ± 0.4 in normal, p affected by stenosis severity (e.g., troponin T, 2 months 0.82 ± 0.03 vs. 0.74 ± 0.03 at 3 months, p-ns). In contrast, mitochondrial function and proteins were normal at 2 months but declined with progression to a critical stenosis (state 3 respiration at 3 months 145 ± 13 vs. 216 ± 5 ng-atoms O2 mg(-1) min(-1) at 2 months, p fashion, increases in stress (e.g., αB-crystalline 2.13 ± 0.2 vs. 1.17 ± 0.13 at 2 months, p < 0.05) and cytoskeletal proteins (e.g., desmin 1.63 ± 0.12 vs. 1.24 ± 0.10 at 2 months, p < 0.05) only developed with more advanced remodeling from a critical stenosis. We conclude that similar degrees of chronic contractile dysfunction can have diverse intrinsic molecular adaptations to ischemia. This spectrum of adaptations may underlie variability in the time course and extent of reversibility in viable chronically dysfunctional myocardium after revascularization.

  15. Associations Between Microbiota, Mitochondrial Function, and Cognition in Chronic Marijuana Users.

    Science.gov (United States)

    Panee, Jun; Gerschenson, Mariana; Chang, Linda

    2018-03-01

    Marijuana (MJ) use is associated with cognitive deficits. Both mitochondrial (mt) dysfunction and gut dysbiosis also affect cognition. We examined whether cognition is related to peripheral blood mononuclear cells' (PBMCs) mt function and fecal microbiota in chronic MJ users. Nineteen chronic MJ users and 20 non-users were evaluated using the Cognition Battery in NIH Toolbox, their mt function for ATP production, and basal and maximal respirations were measured in PBMCs using the Seahorse XFe96 Analyzer, and the abundances of Prevotella and Bacteroides (associated with plant-based and animal product-based diet, respectively) were calculated from stool microbiota analysis. Average Prevotella:Bacteroides ratio was ~13-fold higher in nonusers than users. Lifetime MJ use correlated inversely with Prevotella:Bacteroides ratio (p = 0.05), mt function (p = 0.0027-0.0057), and Flanker Inhibitory Control and Attention (p = 0.041). Prevotella abundance correlated positively, while Bacteroides abundance correlated inversely, with mt function across all participants (p = 0.0004-0.06). Prevotella abundance also correlated positively with scores of Fluid Cognition, Flanker Inhibitory Control and Attention, List Sorting, and Dimension Change Card Sort in MJ users, but not in non-users (interaction-p = 0.018-0.05). Similarly, mt function correlated positively with scores of Fluid Cognition and Flanker Inhibitory Control and Attention in MJ users, but not in non-users (interaction-p = 0.0018-0.08). These preliminary findings suggest that MJ use is associated with alterations of gut microbiota and mt function, which may further contribute to cognitive deficits. We posited that MJ-associated low vegetable/fruit intake may contribute to these changes. Future studies are needed to delineate the relationships among diet, microbiota, mt function, and cognition in MJ users.

  16. Effect of Ginkgo biloba extract on the rat heart mitochondrial function.

    Science.gov (United States)

    Trumbeckaite, Sonata; Bernatoniene, Jurga; Majiene, Daiva; Jakstas, Valdas; Savickas, Arunas; Toleikis, Adolfas

    2007-05-22

    Ginkgo biloba L. (Ginkgoaceae) originated from China, first introduced to Europe in the 18th century, it is now distributed all over the world. The leaves of Ginkgo biloba include a rich complex of active compounds responsible for various pharmacological properties. Ginkgo biloba extract improves blood circulation, protects against oxidative cell damage, blocks platelet aggregation that could be important for prevention of cardiovascular diseases. Therefore the fluid extract from Ginkgo biloba leaves was prepared and tested for it is effect on rat mitochondrial function. Our data showed that 0.5 microl/ml of GE (containing 0.57 ng/ml of rutin, 0.23 ng/ml of quercitrin, 0.105 ng/ml of hyperosid and 0.02 ng/ml of quercetin) had no effect on the State 2 respiration rate of mitochondria with all used substrates: pyruvate+malate, succinate and palmitoyl-L-carnitine. Further increase in GE concentration (2 and 4 microl/ml), increased the State 2 respiration rate with all respiratory substrates in a dose-dependent manner (by 35-116%). The State 3 respiration rate was not affected by GE. In order to identify which compounds of GE could be responsible for the observed effects, we measured the effect of pure flavonoids: rutin, quercetin, hyperosid and quercitrin on mitochondrial respiration. All flavonoids (except of hyperosid) at maximal used concentration, comparable/identical to that in GE, stimulated the State 2 respiration rate only by 8-20%, i.e. less effectively as compared to GE. Therefore, for the explanation of the GE-induced uncoupling of oxidative phosphorylation, other biologically active compounds of GE have to be taken into account in future studies.

  17. Functional redundancy of mitochondrial enoyl-CoA isomerases in the oxidation of unsaturated fatty acids.

    Science.gov (United States)

    van Weeghel, Michel; te Brinke, Heleen; van Lenthe, Henk; Kulik, Wim; Minkler, Paul E; Stoll, Maria S K; Sass, Jörn Oliver; Janssen, Uwe; Stoffel, Wilhelm; Schwab, K Otfried; Wanders, Ronald J A; Hoppel, Charles L; Houten, Sander M

    2012-10-01

    Mitochondrial enoyl-CoA isomerase (ECI1) is an auxiliary enzyme involved in unsaturated fatty acid oxidation. In contrast to most of the other enzymes involved in fatty acid oxidation, a deficiency of ECI1 has yet to be identified in humans. We used wild-type (WT) and Eci1-deficient knockout (KO) mice to explore a potential presentation of human ECI1 deficiency. Upon food withdrawal, Eci1-deficient mice displayed normal blood β-hydroxybutyrate levels (WT 1.09 mM vs. KO 1.10 mM), a trend to lower blood glucose levels (WT 4.58 mM vs. KO 3.87 mM, P=0.09) and elevated blood levels of unsaturated acylcarnitines, in particular C12:1 acylcarnitine (WT 0.03 μM vs. KO 0.09 μM, Pisomerase (Eci2) in mitochondria. Knockdown of Eci2 in Eci1-deficient fibroblasts caused a more pronounced accumulation of C12:1 acylcarnitine on incubation with unsaturated fatty acids (12-fold, P<0.05). We conclude that Eci2 compensates for Eci1 deficiency explaining the mild phenotype of Eci1-deficient mice. Hypoglycemia and accumulation of C12:1 acylcarnitine might be diagnostic markers to identify ECI1 deficiency in humans.

  18. An Introduction to Normalization and Calibration Methods in Functional MRI

    Science.gov (United States)

    Liu, Thomas T.; Glover, Gary H.; Mueller, Bryon A.; Greve, Douglas N.; Brown, Gregory G.

    2013-01-01

    In functional magnetic resonance imaging (fMRI), the blood oxygenation level dependent (BOLD) signal is often interpreted as a measure of neural activity. However, because the BOLD signal reflects the complex interplay of neural, vascular, and metabolic processes, such an interpretation is not always valid. There is growing evidence that changes…

  19. Evaluation of an extended pancreatic function test in normal ...

    African Journals Online (AJOL)

    Exocrine pancreatic response was evaluated in patients with varying degrees of pancreatic damage and in control subjects by means of an extended pancreatic function test (PFT). A second injection of secretin and pancreozymin was given after completion of the standard test. The discriminatory value of the standard PFT ...

  20. Bacterial Signaling Nucleotides Inhibit Yeast Cell Growth by Impacting Mitochondrial and Other Specifically Eukaryotic Functions

    Directory of Open Access Journals (Sweden)

    Andy Hesketh

    2017-07-01

    Full Text Available We have engineered Saccharomyces cerevisiae to inducibly synthesize the prokaryotic signaling nucleotides cyclic di-GMP (cdiGMP, cdiAMP, and ppGpp in order to characterize the range of effects these nucleotides exert on eukaryotic cell function during bacterial pathogenesis. Synthetic genetic array (SGA and transcriptome analyses indicated that, while these compounds elicit some common reactions in yeast, there are also complex and distinctive responses to each of the three nucleotides. All three are capable of inhibiting eukaryotic cell growth, with the guanine nucleotides exhibiting stronger effects than cdiAMP. Mutations compromising mitochondrial function and chromatin remodeling show negative epistatic interactions with all three nucleotides. In contrast, certain mutations that cause defects in chromatin modification and ribosomal protein function show positive epistasis, alleviating growth inhibition by at least two of the three nucleotides. Uniquely, cdiGMP is lethal both to cells growing by respiration on acetate and to obligately fermentative petite mutants. cdiGMP is also synthetically lethal with the ribonucleotide reductase (RNR inhibitor hydroxyurea. Heterologous expression of the human ppGpp hydrolase Mesh1p prevented the accumulation of ppGpp in the engineered yeast and restored cell growth. Extensive in vivo interactions between bacterial signaling molecules and eukaryotic gene function occur, resulting in outcomes ranging from growth inhibition to death. cdiGMP functions through a mechanism that must be compensated by unhindered RNR activity or by functionally competent mitochondria. Mesh1p may be required for abrogating the damaging effects of ppGpp in human cells subjected to bacterial infection.

  1. Overexpression of neurofilament H disrupts normal cell structure and function

    Science.gov (United States)

    Szebenyi, Gyorgyi; Smith, George M.; Li, Ping; Brady, Scott T.

    2002-01-01

    Studying exogenously expressed tagged proteins in live cells has become a standard technique for evaluating protein distribution and function. Typically, expression levels of experimentally introduced proteins are not regulated, and high levels are often preferred to facilitate detection. However, overexpression of many proteins leads to mislocalization and pathologies. Therefore, for normative studies, moderate levels of expression may be more suitable. To understand better the dynamics of intermediate filament formation, transport, and stability in a healthy, living cell, we inserted neurofilament heavy chain (NFH)-green fluorescent protein (GFP) fusion constructs in adenoviral vectors with tetracycline (tet)-regulated promoters. This system allows for turning on or off the synthesis of NFH-GFP at a selected time, for a defined period, in a dose-dependent manner. We used this inducible system for live cell imaging of changes in filament structure and cell shape, motility, and transport associated with increasing NFH-GFP expression. Cells with low to intermediate levels of NFH-GFP were structurally and functionally similar to neighboring, nonexpressing cells. In contrast, overexpression led to pathological alterations in both filament organization and cell function. Copyright 2002 Wiley-Liss, Inc.

  2. Normal function of immunologic stem cells from aged mice

    International Nuclear Information System (INIS)

    Harrison, D.E.; Doubleday, J.W.

    1975-01-01

    Marrow or spleen grafts from aged donor mice produced antibody-forming cells as effectively as did grafts from younger controls in recipients tested 3 to 10 months after the transplantation. All recipients were lethally irradiated, and the T6 chromosome marker was used to demonstrate that they were populated by donor cell lines. Recipients of aged or younger control grafts gave similar responses when stimulated with varying doses of antigen and when tested at different times after the transplantation except in two cases. Recipients of aged spleen grafts gave significantly lower responses than younger controls for the first few weeks after the transplantation. If recipients had been thymectomized before lethal irradiation, aged cell lines (pooled marrow and spleen cells) gave only 37 percent of the responses of younger controls. Given sufficient time and intact young recipients, immunologic stem cell lines from old donors populated recipients with cells having normal immune responses. These results suggest that age-related immunologic defects are not intrinsically timed in the precursor cell lines that populate the immune system. (U.S.)

  3. Renal functional reserve in children with apparently normal congenital solitary functioning kidney.

    Science.gov (United States)

    Peco-Antić, Amira; Paripović, Dušan; Kotur-Stevuljević, Jelena; Stefanović, Aleksandra; Sćekić, Gordana; Miloševski-Lomić, Gordana

    2012-10-01

    The aim of the study was to investigate renal functional reserve (RFR) and to assess its relationship with serum cystatin C and blood pressure in children with apparently normal congenital solitary functioning kidney (SFK). RFR was obtained from the difference of endogenous creatinine clearance (CrCs) before and after a meat-free oral protein load (OPL) in the patients who were pre-treated with cimetidine. Serum cystatin C and urinary protein excretion were determined before and after OPL. Among 22 patients (13 boys), aged 9.5 ± 4.3 years, 72.7% had increased serum cystatin C, and 54.5% had decreased RFR. Following OPL, CrCs and urine creatinine increased, while serum creatinine and cystatin C remained unchanged. The multiple regression analysis demonstrated that cystatin C could predict more than 90% of RFR variability. Half of the patients with apparently normal SFK had decreased RFR. Serum cystatin C is one of the best predictors of RFR. Copyright © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  4. The metabolic enhancer piracetam ameliorates the impairment of mitochondrial function and neurite outgrowth induced by ß-amyloid peptide

    Science.gov (United States)

    Kurz, C; Ungerer, I; Lipka, U; Kirr, S; Schütt, T; Eckert, A; Leuner, K; Müller, WE

    2010-01-01

    Background and purpose: β-Amyloid peptide (Aβ) is implicated in the pathogenesis of Alzheimer's disease by initiating a cascade of events from mitochondrial dysfunction to neuronal death. The metabolic enhancer piracetam has been shown to improve mitochondrial dysfunction following brain aging and experimentally induced oxidative stress. Experimental approach: We used cell lines (PC12 and HEK cells) and murine dissociated brain cells. The protective effects of piracetam in vitro and ex vivo on Aβ-induced impairment of mitochondrial function (as mitochondrial membrane potential and ATP production), on secretion of soluble Aβ and on neurite outgrowth in PC12 cells were investigated. Key results: Piracetam improves mitochondrial function of PC12 cells and acutely dissociated brain cells from young NMRI mice following exposure to extracellular Aβ1-42. Similar protective effects against Aβ1-42 were observed in dissociated brain cells from aged NMRI mice, or mice transgenic for mutant human amyloid precursor protein (APP) treated with piracetam for 14 days. Soluble Aβ load was markedly diminished in the brain of those animals after treatment with piracetam. Aβ production by HEK cells stably transfected with mutant human APP was elevated by oxidative stress and this was reduced by piracetam. Impairment of neuritogenesis is an important consequence of Aβ-induced mitochondrial dysfunction and Aβ-induced reduction of neurite growth in PC12 cells was substantially improved by piracetam. Conclusion and implications: Our findings strongly support the concept of improving mitochondrial function as an approach to ameliorate the detrimental effects of Aβ on brain function. This article is commented on by Moncada, pp. 217–219 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476-5381.2010.00706.x and to view related papers by Pravdic et al. and Puerta et al. visit http://dx.doi.org/10.1111/j.1476-5381.2010.00698.x and http://dx.doi.org/10.1111/j

  5. Endotoxemia Engages the RhoA Kinase Pathway to Impair Cardiac Function By Altering Cytoskeleton, Mitochondrial Fission, and Autophagy.

    Science.gov (United States)

    Preau, Sebastien; Delguste, Florian; Yu, Yichi; Remy-Jouet, Isabelle; Richard, Vincent; Saulnier, Fabienne; Boulanger, Eric; Neviere, Remi

    2016-04-01

    The RhoA/ROCK pathway controls crucial biological processes involved in cardiovascular pathophysiology, such as cytoskeleton dynamics, vascular smooth muscle contraction, and inflammation. In this work, we tested whether Rho kinase inhibition would beneficially impact cardiac cytoskeleton organization, bioenergetics, and autophagy in experimental endotoxemia induced by lipopolysaccharides (LPSs) in mice. Fasudil, a potent ROCK inhibitor, prevented LPS-induced cardiac inflammation, oxidative stress, cytoskeleton disarray, and mitochondrial injury. ROCK inhibition prevented phosphorylation of cofilin and dynamin-related protein-1, which promotes stabilization-polymerization of F-actin and mediates mitochondrial fission, respectively. Pyr1, which exclusively alters actin dynamics, prevented LPS-induced myocardial dysfunction, suggesting that beneficial impact of ROCK inhibition was not mainly related to pleiotropic effects of fasudil on cardiac inflammation and oxidative stress. Fasudil reduced mitochondrial fragmentation, stimulated initiation of autophagy, and elicited cardioprotection in LPS heart. Mdivi-1, a potent mitochondria fission inhibitor, converted cardioprotective autophagy to an inefficient form due to cargo loading failure in which autophagic vacuoles fail to trap cytosolic cargo, despite their formation at enhanced rates and lysosomal elimination. In experimental endotoxemia, cardioprotection by RhoA/ROCK inhibition may be related to changes in actin cytoskeleton reorganization and mitochondrial homeostasis. Improvement of LPS-induced mitochondrial dysfunction by fasudil was attributed to inhibition of ROCK-dependent Drp1 phosphorylation and activation of autophagic processes that can limit mitochondrial fragmentation and enhance degradation of damaged mitochondria, respectively. Fasudil prevented LPS-induced heart oxidative stress, abnormal F-actin distribution, and oxidative phosphorylation, which concur to improve cardiac contractile and

  6. Transcranial low-level laser therapy improves brain mitochondrial function and cognitive impairment in D-galactose-induced aging mice.

    Science.gov (United States)

    Salehpour, Farzad; Ahmadian, Nahid; Rasta, Seyed Hossein; Farhoudi, Mehdi; Karimi, Pouran; Sadigh-Eteghad, Saeed

    2017-10-01

    Mitochondrial function plays a key role in the aging-related cognitive impairment, and photoneuromodulation of mitochondria by transcranial low-level laser therapy (LLLT) may contribute to its improvement. This study focused on the transcranial LLLT effects on the D-galactose (DG)-induced mitochondrial dysfunction, apoptosis, and cognitive impairment in mice. For this purpose, red and near-infrared (NIR) laser wavelengths (660 and 810 nm) at 2 different fluencies (4 and 8 J/cm 2 ) at 10-Hz pulsed wave mode were administrated transcranially 3 d/wk in DG-received (500 mg/kg/subcutaneous) mice model of aging for 6 weeks. Spatial and episodic-like memories were assessed by the Barnes maze and What-Where-Which (WWWhich) tasks. Brain tissues were analyzed for mitochondrial function including active mitochondria, adenosine triphosphate, and reactive oxygen species levels, as well as membrane potential and cytochrome c oxidase activity. Apoptosis-related biomarkers, namely, Bax, Bcl-2, and caspase-3 were evaluated by Western blotting method. Laser treatments at wavelengths of 660 and 810 nm at 8 J/cm 2 attenuated DG-impaired spatial and episodic-like memories. Also, results showed an obvious improvement in the mitochondrial function aspects and modulatory effects on apoptotic markers in aged mice. However, same wavelengths at the fluency of 4 J/cm 2 had poor effect on the behavioral and molecular indexes in aging model. This data indicates that transcranial LLLT at both of red and NIR wavelengths at the fluency of 8 J/cm 2 has a potential to ameliorate aging-induced mitochondrial dysfunction, apoptosis, and cognitive impairment. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. A Functional Approach towards Understanding the Role of the Mitochondrial Respiratory Chain in an Endomycorrhizal Symbiosis

    Science.gov (United States)

    Mercy, Louis; Lucic-Mercy, Eva; Nogales, Amaia; Poghosyan, Areg; Schneider, Carolin; Arnholdt-Schmitt, Birgit

    2017-01-01

    Arbuscular mycorrhizal fungi (AMF) are crucial components of fertile soils, able to provide several ecosystem services for crop production. Current economic, social and legislative contexts should drive the so-called “second green revolution” by better exploiting these beneficial microorganisms. Many challenges still need to be overcome to better understand the mycorrhizal symbiosis, among which (i) the biotrophic nature of AMF, constraining their production, while (ii) phosphate acts as a limiting factor for the optimal mycorrhizal inoculum application and effectiveness. Organism fitness and adaptation to the changing environment can be driven by the modulation of mitochondrial respiratory chain, strongly connected to the phosphorus processing. Nevertheless, the role of the respiratory function in mycorrhiza remains largely unexplored. We hypothesized that the two mitochondrial respiratory chain components, alternative oxidase (AOX) and cytochrome oxidase (COX), are involved in specific mycorrhizal behavior. For this, a complex approach was developed. At the pre-symbiotic phase (axenic conditions), we studied phenotypic responses of Rhizoglomus irregulare spores with two AOX and COX inhibitors [respectively, salicylhydroxamic acid (SHAM) and potassium cyanide (KCN)] and two growth regulators (abscisic acid – ABA and gibberellic acid – Ga3). At the symbiotic phase, we analyzed phenotypic and transcriptomic (genes involved in respiration, transport, and fermentation) responses in Solanum tuberosum/Rhizoglomus irregulare biosystem (glasshouse conditions): we monitored the effects driven by ABA, and explored the modulations induced by SHAM and KCN under five phosphorus concentrations. KCN and SHAM inhibited in vitro spore germination while ABA and Ga3 induced differential spore germination and hyphal patterns. ABA promoted mycorrhizal colonization, strong arbuscule intensity and positive mycorrhizal growth dependency (MGD). In ABA treated plants, R. irregulare

  8. Bacterial Signaling Nucleotides Inhibit Yeast Cell Growth by Impacting Mitochondrial and Other Specifically Eukaryotic Functions.

    Science.gov (United States)

    Hesketh, Andy; Vergnano, Marta; Wan, Chris; Oliver, Stephen G

    2017-07-25

    We have engineered Saccharomyces cerevisiae to inducibly synthesize the prokaryotic signaling nucleotides cyclic di-GMP (cdiGMP), cdiAMP, and ppGpp in order to characterize the range of effects these nucleotides exert on eukaryotic cell function during bacterial pathogenesis. Synthetic genetic array (SGA) and transcriptome analyses indicated that, while these compounds elicit some common reactions in yeast, there are also complex and distinctive responses to each of the three nucleotides. All three are capable of inhibiting eukaryotic cell growth, with the guanine nucleotides exhibiting stronger effects than cdiAMP. Mutations compromising mitochondrial function and chromatin remodeling show negative epistatic interactions with all three nucleotides. In contrast, certain mutations that cause defects in chromatin modification and ribosomal protein function show positive epistasis, alleviating growth inhibition by at least two of the three nucleotides. Uniquely, cdiGMP is lethal both to cells growing by respiration on acetate and to obligately fermentative petite mutants. cdiGMP is also synthetically lethal with the ribonucleotide reductase (RNR) inhibitor hydroxyurea. Heterologous expression of the human ppGpp hydrolase Mesh1p prevented the accumulation of ppGpp in the engineered yeast and restored cell growth. Extensive in vivo interactions between bacterial signaling molecules and eukaryotic gene function occur, resulting in outcomes ranging from growth inhibition to death. cdiGMP functions through a mechanism that must be compensated by unhindered RNR activity or by functionally competent mitochondria. Mesh1p may be required for abrogating the damaging effects of ppGpp in human cells subjected to bacterial infection. IMPORTANCE During infections, pathogenic bacteria can release nucleotides into the cells of their eukaryotic hosts. These nucleotides are recognized as signals that contribute to the initiation of defensive immune responses that help the infected

  9. Acute and perinatal-programming effects of a fat-rich diet on rat muscle mitochondrial function and hepatic lipid accumulation

    DEFF Research Database (Denmark)

    Hellgren, Lars; Jensen, Runa I.; Waterstradt, Michelle S. G.

    2014-01-01

    Objective. Maternal high-fat intake during pregnancy may have long-term consequences in the offspring. Since this might relate to the capacity of mitochondrial metabolic adaptation and hepatic lipid metabolism, we investigated how maternal high-fat intake affected mitochondrial function and hepat...

  10. Mitochondrial H2O2 signaling is controlled by the concerted action of peroxiredoxin III and sulfiredoxin: Linking mitochondrial function to circadian rhythm.

    Science.gov (United States)

    Rhee, Sue Goo; Kil, In Sup

    2016-11-01

    Mitochondria produce hydrogen peroxide (H 2 O 2 ) during energy metabolism in most mammalian cells as well as during the oxidation of cholesterol associated with the synthesis of steroid hormones in steroidogenic cells. Some of the H 2 O 2 produced in mitochondria is released into the cytosol, where it serves as a key regulator of various signaling pathways. Given that mitochondria are equipped with several H 2 O 2 -eliminating enzymes, however, it had not been clear how mitochondrial H 2 O 2 can escape destruction by these enzymes for such release. Peroxiredoxin III (PrxIII) is the most abundant and efficient H 2 O 2 -eliminating enzyme in mitochondria of most cell types. We found that PrxIII undergoes reversible inactivation through hyperoxidation of its catalytic cysteine residue to cysteine sulfinic acid, and that release of mitochondrial H 2 O 2 likely occurs as a result of such PrxIII inactivation. The hyperoxidized form of PrxIII (PrxIII-SO 2 H) is reduced and reactivated by sulfiredoxin (Srx). We also found that the amounts of PrxIII-SO 2 H and Srx undergo antiphasic circadian oscillation in mitochondria of the adrenal gland, heart, and brown adipose tissue of mice maintained under normal conditions. Cytosolic Srx was found to be imported into mitochondria via a mechanism that requires formation of a disulfide-linked complex with heat shock protein 90, which is likely promoted by H 2 O 2 released from mitochondria. The imported Srx was found to be degraded by Lon protease in a manner dependent on PrxIII hyperoxidation state. The coordinated import and degradation of Srx underlie Srx oscillation and consequent PrxIII-SO 2 H oscillation in mitochondria. The rhythmic change in the amount of PrxIII-SO 2 H suggests that mitochondrial release of H 2 O 2 is also likely a circadian event that conveys temporal information on steroidogenesis in the adrenal gland and on energy metabolism in heart and brown adipose tissue to cytosolic signaling pathways. Copyright

  11. The Amaryllidaceae Isocarbostyril Narciclasine Induces Apoptosis By Activation of the Death Receptor and/or Mitochondrial Pathways in Cancer Cells But Not in Normal Fibroblasts

    Directory of Open Access Journals (Sweden)

    Patrick Dumont

    2007-09-01

    Full Text Available Our study has shown that the Amaryllidaceae isocarbostyril narciclasine induces marked apoptosismediated cytotoxic effects in human cancer cells but not in normal fibroblasts by triggering the activation of the initiator caspases of the death receptor pathway (caspase-8 and caspase-10 at least in human MCF-7 breast and PC-3 prostate carcinoma cells. The formation of the Fas and death receptor 4 (DR4 death-inducing signaling complex was clearly evidenced in MCF-7 and PC-3 cancer cells. Caspase-8 was found to interact with Fas and DR4 receptors on narciclasine treatment. However, narciclasine-induced downstream apoptotic pathways in MCF-7 cells diverged from those in PC-3 cells, where caspase-8 directly activated effector caspases such as caspase-3 in the absence of any further release of mitochondrial proapoptotic effectors. In contrast, in MCF-7 cells, the apoptotic process was found to require an amplification step that is mitochondria-dependent, with Bid processing, release of cytochrome c, caspase-9 activation. It is postulated that the high selectivity of narciclasine to cancer cells might be linked, at least in part, to this activation of the death receptor pathway. Normal human fibroblasts appear approximately 250-fold less sensitive to narciclasine, which does not induce apoptosis in these cells probably due to the absence of death receptor pathway activation.

  12. Intranasal Oxytocin Normalizes Amygdala Functional Connectivity in Posttraumatic Stress Disorder.

    Science.gov (United States)

    Koch, Saskia B J; van Zuiden, Mirjam; Nawijn, Laura; Frijling, Jessie L; Veltman, Dick J; Olff, Miranda

    2016-07-01

    The neuropeptide oxytocin (OT) has been suggested as a promising pharmacological agent for medication-enhanced psychotherapy in posttraumatic stress disorder (PTSD) because of its anxiolytic and prosocial properties. We therefore investigated the behavioral and neurobiological effects of a single intranasal OT administration (40 IU) in PTSD patients. We conducted a randomized, placebo-controlled, cross-over resting-state fMRI study in male and female police officers with (n=37, 21 males) and without PTSD (n=40, 20 males). We investigated OT administration effects on subjective anxiety and functional connectivity of basolateral (BLA) and centromedial (CeM) amygdala subregions with prefrontal and salience processing areas. In PTSD patients, OT administration resulted in decreased subjective anxiety and nervousness. Under placebo, male PTSD patients showed diminished right CeM to left ventromedial prefrontal cortex (vmPFC) connectivity compared with male trauma-exposed controls, which was reinstated after OT administration. Additionally, female PTSD patients showed enhanced right BLA to bilateral dorsal anterior cingulate cortex (dACC) connectivity compared with female trauma-exposed controls, which was dampened after OT administration. Although caution is warranted, our findings tentatively suggest that OT has the potential to diminish anxiety and fear expression of the amygdala in PTSD, either via increased control of the vmPFC over the CeM (males) or via decreased salience processing of the dACC and BLA (females). Our findings add to accumulating evidence that OT administration could potentially enhance treatment response in PTSD.

  13. Alternative function for the mitochondrial SAM complex in biogenesis of alpha-helical TOM proteins.

    Science.gov (United States)

    Stojanovski, Diana; Guiard, Bernard; Kozjak-Pavlovic, Vera; Pfanner, Nikolaus; Meisinger, Chris

    2007-12-03

    The mitochondrial outer membrane contains two preprotein translocases: the general translocase of outer membrane (TOM) and the beta-barrel-specific sorting and assembly machinery (SAM). TOM functions as the central entry gate for nuclear-encoded proteins. The channel-forming Tom40 is a beta-barrel protein, whereas all Tom receptors and small Tom proteins are membrane anchored by a transmembrane alpha-helical segment in their N- or C-terminal portion. Synthesis of Tom precursors takes place in the cytosol, and their import occurs via preexisting TOM complexes. The precursor of Tom40 is then transferred to SAM for membrane insertion and assembly. Unexpectedly, we find that the biogenesis of alpha-helical Tom proteins with a membrane anchor in the C-terminal portion is SAM dependent. Each SAM protein is necessary for efficient membrane integration of the receptor Tom22, whereas assembly of the small Tom proteins depends on Sam37. Thus, the substrate specificity of SAM is not restricted to beta-barrel proteins but also includes the majority of alpha-helical Tom proteins.

  14. Quercetin ameliorates hypobaric hypoxia-induced memory impairment through mitochondrial and neuron function adaptation via the PGC-1α pathway.

    Science.gov (United States)

    Liu, Peng; Zou, Dan; Yi, Long; Chen, Mingliang; Gao, Yanxiang; Zhou, Rui; Zhang, Qianyong; Zhou, Yong; Zhu, Jundong; Chen, Ka; Mi, Mantian

    2015-01-01

    Acute hypobaric hypoxia (HH) causes persistent cognitive impairment, affecting memory function specifically. Mitochondrial dysfunction and synaptic morphological change were the prominent pathological features of HH exposure on brain. Quercetin, a flavonoid found in fruits, vegetables, leaves and grains, is reported to prevent ischemia induced by neuronal injury. This study investigated the efficacy of quercetin to ameliorate HH-induced memory deficit. Rats were exposed to HH equivalent to 5000 m for 7 days in a decompression chamber and received quercetin daily (50, 75 or 100 mg/kg·bw) via gavage during the period of exposure. Cognitive performance was assessed by the Morris water maze test. In vitro, the effect of quercetin was tested in hippocampus tissue. Quercetin, especially at 100 mg/kg·bw, significantly reduced HH-induced memory decline. Meanwhile, HH-induced hippocampus mitochondrial and synaptic lesions were ameliorated by quercetin. Furthermore, quercetin regulated the expression of sirtuin 1(Sirt1), PGC-1α, and the proteins related with mitochondrial biogenesis and dynamics. Moreover, quercetin increased expression of fibronectin type III domain-containing protein 5 (FNDC5) and brain-derived neurotrophic factor (BDNF), showing the PGC-1α/FNDC5/BNDF pathways might be involved in neuronal adaptation. The results suggest quercetin has prophylactic potential for amelioration of HH-induced memory impairment, which is associated with the mitochondrial and neuronal adaptation in hippocampus.

  15. Estrogen-related receptor α is essential for the expression of antioxidant protection genes and mitochondrial function

    International Nuclear Information System (INIS)

    Rangwala, Shamina M.; Li, Xiaoyan; Lindsley, Loren; Wang, Xiaomei; Shaughnessy, Stacey; Daniels, Thomas G.; Szustakowski, Joseph; Nirmala, N.R.; Wu, Zhidan; Stevenson, Susan C.

    2007-01-01

    Estrogen-related receptor α (ERRα) is an important mediator of mitochondrial biogenesis and function. To investigate the transcriptional network controlling these phenomena, we investigated mitochondrial gene expression in embryonic fibroblasts isolated from ERRα null mice. Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) stimulated mitochondrial gene expression program in control cells, but not in the ERRα null cells. Interestingly, the induction of levels of mitochondrial oxidative stress protection genes in response to increased PGC-1α levels was dependent on ERRα. Furthermore, we found that the PGC-1α-mediated induction of estrogen-related receptor γ and nuclear respiratory factor 2 (NRF-2), was dependent on the presence of ERRα. Basal levels of NRF-2 were decreased in the absence of ERRα. The absence of ERRα resulted in a decrease in citrate synthase enzyme activity in response to PGC-1α overexpression. Our results indicate an essential role for ERRα as a key regulator of oxidative metabolism

  16. Mitochondria know no boundaries: mechanisms and functions of intercellular mitochondrial transfer

    Directory of Open Access Journals (Sweden)

    Daniel Torralba

    2016-09-01

    Full Text Available Mitochondria regulate multiple cell processes, including calcium signaling, apoptosis and cell metabolism. Mitochondria contain their own circular genome encoding selected subunits of the oxidative phosphorylation complexes. Recent findings reveal that, in addition to being maternally inherited, mitochondria can traverse cell boundaries and thus be horizontally transferred between cells. Although the physiological relevance of this phenomenon is still under debate, mitochondria uptake rescues mitochondrial respiration defects in recipient cells and regulates signaling, proliferation or chemotherapy resistance in vitro and in vivo. In this review, we outline the pathophysiological consequences of horizontal mitochondrial transfer and offer a perspective on the cellular and molecular mechanisms mediating their intercellular transmission, including tunneling nanotubes, extracellular vesicles, cellular fusion and GAP junctions. The physiological relevance of mitochondrial transfer and the potential therapeutic application of this exchange for treating mitochondrial-related diseases are discussed.

  17. Muscle biopsies from human muscle diseases with myopathic pathology reveal common alterations in mitochondrial function.

    Science.gov (United States)

    Sunitha, Balaraju; Gayathri, Narayanappa; Kumar, Manish; Keshava Prasad, Thottethodi Subrahmanya; Nalini, Atchayaram; Padmanabhan, Balasundaram; Srinivas Bharath, Muchukunte Mukunda

    2016-07-01

    Muscle diseases are clinically and genetically heterogeneous and manifest as dystrophic, inflammatory and myopathic pathologies, among others. Our previous study on the cardiotoxin mouse model of myodegeneration and inflammation linked muscle pathology with mitochondrial damage and oxidative stress. In this study, we investigated whether human muscle diseases display mitochondrial changes. Muscle biopsies from muscle disease patients, represented by dysferlinopathy (dysfy) (dystrophic pathology; n = 43), polymyositis (PM) (inflammatory pathology; n = 24), and distal myopathy with rimmed vacuoles (DMRV) (distal myopathy; n = 31) were analyzed. Mitochondrial damage (ragged blue and COX-deficient fibers) was revealed in dysfy, PM, and DMRV cases by enzyme histochemistry (SDH and COX-SDH), electron microscopy (vacuolation and altered cristae) and biochemical assays (significantly increased ADP/ATP ratio). Proteomic analysis of muscle mitochondria from all three muscle diseases by isobaric tag for relative and absolute quantitation labeling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis demonstrated down-regulation of electron transport chain (ETC) complex subunits, assembly factors and Krebs cycle enzymes. Interestingly, 80 of the under-expressed proteins were common among the three pathologies. Assay of ETC and Krebs cycle enzyme activities validated the MS data. Mitochondrial proteins from muscle pathologies also displayed higher tryptophan (Trp) oxidation and the same was corroborated in the cardiotoxin model. Molecular modeling predicted Trp oxidation to alter the local structure of mitochondrial proteins. Our data highlight mitochondrial alterations in muscle pathologies, represented by morphological changes, altered mitochondrial proteome and protein oxidation, thereby establishing the role of mitochondrial damage in human muscle diseases. We investigated whether human muscle diseases display mitochondrial changes. Muscle biopsies

  18. Reproduction Does Not Adversely Affect Liver Mitochondrial Respiratory Function but Results in Lipid Peroxidation and Increased Antioxidants in House Mice.

    Science.gov (United States)

    Mowry, Annelise V; Kavazis, Andreas N; Sirman, Aubrey E; Potts, Wayne K; Hood, Wendy R

    2016-01-01

    Reproduction is thought to come at a cost to longevity. Based on the assumption that increased energy expenditure during reproduction is associated with increased free-radical production by mitochondria, oxidative damage has been suggested to drive this trade-off. We examined the impact of reproduction on liver mitochondrial function by utilizing post-reproductive and non-reproductive house mice (Mus musculus) living under semi-natural conditions. The age-matched post-reproductive and non-reproductive groups were compared after the reproductive females returned to a non-reproductive state, so that both groups were in the same physiological state at the time the liver was collected. Despite increased oxidative damage (p = 0.05) and elevated CuZnSOD (p = 0.002) and catalase (p = 0.04) protein levels, reproduction had no negative impacts on the respiratory function of liver mitochondria. Specifically, in a post-reproductive, maintenance state the mitochondrial coupling (i.e., respiratory control ratio) of mouse livers show no negative impacts of reproduction. In fact, there was a trend (p = 0.059) to suggest increased maximal oxygen consumption by liver mitochondria during the ADP stimulated state (i.e., state 3) in post-reproduction. These findings suggest that oxidative damage may not impair mitochondrial respiratory function and question the role of mitochondria in the trade-off between reproduction and longevity. In addition, the findings highlight the importance of quantifying the respiratory function of mitochondria in addition to measuring oxidative damage.

  19. Targeting Glial Mitochondrial Function for Protection from Cerebral Ischemia: Relevance, Mechanisms, and the Role of MicroRNAs

    Directory of Open Access Journals (Sweden)

    Le Li

    2016-01-01

    Full Text Available Astrocytes and microglia play crucial roles in the response to cerebral ischemia and are effective targets for stroke therapy in animal models. MicroRNAs (miRs are important posttranscriptional regulators of gene expression that function by inhibiting the translation of select target genes. In astrocytes, miR expression patterns regulate mitochondrial function in response to oxidative stress via targeting of Bcl2 and heat shock protein 70 family members. Mitochondria play an active role in microglial activation, and miRs regulate the microglial neuroinflammatory response. As endogenous miR expression patterns can be altered with exogenous mimics and inhibitors, miR-targeted therapies represent a viable intervention to optimize glial mitochondrial function and improve clinical outcome following cerebral ischemia. In the present article, we review the role that astrocytes and microglia play in neuronal function and fate following ischemic stress, discuss the relevance of mitochondria in the glial response to injury, and present current evidence implicating miRs as critical regulators in the glial mitochondrial response to cerebral ischemia.

  20. Alteration of mitochondrial function and insulin sensitivity in primary mouse skeletal muscle cells isolated from transgenic and knockout mice: role of ogg1.

    Science.gov (United States)

    Yuzefovych, Larysa V; Schuler, A Michele; Chen, Jemimah; Alvarez, Diego F; Eide, Lars; Ledoux, Susan P; Wilson, Glenn L; Rachek, Lyudmila I

    2013-08-01

    Recent evidence has linked mitochondrial dysfunction and DNA damage, increased oxidative stress in skeletal muscle, and insulin resistance (IR). The purpose of this study was to determine the role of the DNA repair enzyme, human 8-oxoguanine DNA glycosylase/apurinic/apyrimidinic lyase (hOGG1), on palmitate-induced mitochondrial dysfunction and IR in primary cultures of skeletal muscle derived from hind limb of ogg1(-/-) knockout mice and transgenic mice, which overexpress human (hOGG1) in mitochondria (transgenic [Tg]/MTS-hOGG1). Following exposure to palmitate, we evaluated mitochondrial DNA (mtDNA) damage, mitochondrial function, production of mitochondrial reactive oxygen species (mtROS), mitochondrial mass, JNK activation, insulin signaling pathways, and glucose uptake. Palmitate-induced mtDNA damage, mtROS, mitochondrial dysfunction, and activation of JNK were all diminished, whereas ATP levels, mitochondrial mass, insulin-stimulated phosphorylation of Akt (Ser 473), and insulin sensitivity were increased in primary myotubes isolated from Tg/MTS-hOGG1 mice compared to myotubes isolated from either knockout or wild-type mice. In addition, both basal and maximal respiratory rates during mitochondrial oxidation on pyruvate showed a variable response, with some animals displaying an increased respiration in muscle fibers isolated from the transgenic mice. Our results support the model that DNA repair enzyme OGG1 plays a pivotal role in repairing mtDNA damage, and consequently, in mtROS production and regulating downstream events leading to IR in skeletal muscle.

  1. Aspects of thyroid hormone regulation of mitochondrial function in diabetes and diabetic complications

    DEFF Research Database (Denmark)

    Anthonsen, Stine

    Type 2 diabetes (T2DM) has been related to lifestyle, obesity and age; however, T2DM has also been associated with mitochondrial dysfunction. Mitochondria produce ATP and during this synthesis, reactive oxygen species are generated. Increased levels of reactive oxygen species are associated...... with development of diabetic complications. ATP-synthesis and ROS-generation are dependent on mitochondrial membrane potential (MMP), which indicate the activity of the mitochondria....

  2. The Comparison of the Executive-Neurological Functions of the Narcotic Addicted and Normal Adults

    Directory of Open Access Journals (Sweden)

    Fereshteh Amini

    2010-05-01

    Full Text Available Aim: The purpose of present research was the comparison of executive-neurological functions of narcotics addicted and normal adults. Method: In this causal-comparative study 38 narcotics addicted person selected of two addiction treatment clinics in Tehran, and 38 normal persons selected through available sampling. The both groups assessed by neuropsychological tests namely: the Wisconsin classification cards. Results: The analysis of data indicated the significant difference on executive functions of addicted and normal groups. That is addicted group were poorer than normal group on executive functions. Conclusion: The findings of present research showed the addicts have weaker executive functions than the normal persons. In other words, the addicts showed impairments on cognitive flexibility and formation of change concepts.

  3. Succinate dehydrogenase assembly factor 2 is needed for assembly and activity of mitochondrial complex II and for normal root elongation in Arabidopsis.

    Science.gov (United States)

    Huang, Shaobai; Taylor, Nicolas L; Ströher, Elke; Fenske, Ricarda; Millar, A Harvey

    2013-02-01

    Mitochondria complex II (succinate dehydrogenase, SDH) plays a central role in respiratory metabolism as a component of both the electron transport chain and the tricarboxylic acid cycle. We report the identification of an SDH assembly factor by analysis of T-DNA insertions in At5g51040, a protein with unknown function that was identified by mass spectrometry analysis as a low abundance mitochondrial protein. This gene is co-expressed with a number of genes encoding mitochondrial proteins, including SDH1-1, and has low partial sequence similarity to human SDHAF2, a protein required for flavin-adenine dinucleotide (FAD) insertion into SDH. In contrast to observations of other SDH deficient lines in Arabidopsis, the sdhaf2 line did not affect photosynthetic rate or stomatal conductance, but instead showed inhibition of primary root elongation with early lateral root emergence, presumably due to the low SDH activity caused by the reduced abundance of SDHAF2. Both roots and leaves showed succinate accumulation but different responses in the abundance of other organic acids and amino acids assayed. Isolated mitochondria showed lowered SDH1 protein abundance, lowered maximal SDH activity and less protein-bound flavin-adenine dinucleotide (FAD) at the molecular mass of SDH1 in the gel separation. The short root phenotype and SDH function of sdhaf2 was fully complemented by transformation with SDHAF2. Application of the SDH inhibitor, malonate, phenocopied the sdhaf2 root architecture in WT. Whole root respiratory assays showed no difference between WT and sdhaf2, but micro-respirometry of the tips of roots clearly showed low oxygen consumption in sdhaf2 which could explain a metabolic deficit responsible for root tip growth. © 2012 The Authors The Plant Journal © 2012 Blackwell Publishing Ltd.

  4. ACL-RSI and KOOS Measures Predict Normal Knee Function after ACL-SPORTS Training

    OpenAIRE

    White, Kathleen; Zeni, Joseph; Snyder-Mackler, Lynn

    2014-01-01

    Objectives: After anterior cruciate ligament reconstruction (ACLR) athletes commonly report increased fear of re-injury and below normal knee function. Implementing a post-operative training protocol (ACL-SPORTS Training) to improve patient perceived knee function, may improve short term outcomes after surgery. Identifying pre-training measures that predict normal knee function after training may allow us to determine who may respond to the treatment intervention. The purpose of this study wa...

  5. Reproductive aging is associated with changes in oocyte mitochondrial dynamics, function, and mtDNA quantity.

    Science.gov (United States)

    Babayev, Elnur; Wang, Tianren; Szigeti-Buck, Klara; Lowther, Katie; Taylor, Hugh S; Horvath, Tamas; Seli, Emre

    2016-11-01

    Mitochondria affect numerous aspects of mammalian reproduction. We investigated whether the decrease in oocyte quality associated with aging is related to altered mitochondria. Oocytes from old (12 months) and young (9 weeks) C57BL/6J mice were compared in relation to: mitochondria morphology and dynamics (mitochondria density, coverage, size and shape) throughout folliculogenesis; levels of mitochondrial DNA (mtDNA); mitochondrial stress reflected in the expression of mitochondrial unfolded protein response (mt-UPR) genes; and levels of reactive oxygen species (ROS) under baseline conditions and following H 2 O 2 treatment. In old mice, mitochondria of primary follicle-enclosed oocytes were smaller, with lower mitochondria coverage (total mitochondria μm 2 /μm 2 cytosol area) (pchanges were not significant. Mature oocytes (Metaphase II-MII) from old mice had significantly less mtDNA (paged MII oocytes were also higher following pretreatment with H 2 O 2 (pAging is associated with altered mitochondrial morphological parameters and decreased mtDNA levels in oocytes, as well as an increase in ROS under stressful conditions and elevated expression of mitochondrial stress response gene Hspd1. Delineation of the mechanisms underlying mitochondrial changes associated with ageing may help in the development of diagnostic and therapeutic tools in reproductive medicine. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Genetic risk factors affecting mitochondrial function are associated with kidney disease in people with Type 1 diabetes

    DEFF Research Database (Denmark)

    Swan, E J; Salem, R M; Sandholm, N

    2015-01-01

    individuals with diabetic kidney disease) vs. control (n = 903 individuals with diabetes and no renal disease) approach. All people included in the analysis were of white European origin and were diagnosed with Type 1 diabetes before the age of 31 years. Replication was conducted in 5093 people with similar...... or end-stage renal disease. A total of 38 SNPs in nuclear genes influencing mitochondrial function were nominally associated with diabetic kidney disease and 16 SNPS were associated with end-stage renal disease, secondary to diabetic kidney disease, with meta-analyses confirming the same direction...... of effect. Three independent signals (seven SNPs) were common to the replication data for both phenotypes with Type 1 diabetes and persistent proteinuria or end-stage renal disease. CONCLUSIONS: Our results suggest that SNPs in nuclear genes that influence mitochondrial function are significantly associated...

  7. Skeletal muscle mitochondrial function cannot be properly inferred from PCr resynthesis without taking pH changes into account

    OpenAIRE

    Ratel, Sebastien; Martin, Vincent; Tonson, Anne; Cozzone, Patrick J.; Bendahan, David

    2012-01-01

    International audience; We have read with much interest the paper recently 9 published by Khushu et al. regarding the impaired muscle 10 metabolism in hypothyroid patients [1]. Although the results 11 of this investigation are of potential interest, we are actually 12 concerned about the utilization of the phosphocreatine 13 recovery rate constant (kPCr) as a simple index of 14 mitochondrial function and the corresponding conclusions 15 regarding the impact of hypothyroidism on muscle metab-1...

  8. Age-related normal structural and functional ventricular values in cardiac function assessed by magnetic resonance

    International Nuclear Information System (INIS)

    Fiechter, Michael; Gaemperli, Oliver; Kaufmann, Philipp A; Fuchs, Tobias A; Gebhard, Catherine; Stehli, Julia; Klaeser, Bernd; Stähli, Barbara E; Manka, Robert; Manes, Costantina; Tanner, Felix C

    2013-01-01

    The heart is subject to structural and functional changes with advancing age. However, the magnitude of cardiac age-dependent transformation has not been conclusively elucidated. This retrospective cardiac magnetic resonance (CMR) study included 183 subjects with normal structural and functional ventricular values. End systolic volume (ESV), end diastolic volume (EDV), and ejection fraction (EF) were obtained from the left and the right ventricle in breath-hold cine CMR. Patients were classified into four age groups (20–29, 30–49, 50–69, and ≥70 years) and cardiac measurements were compared using Pearson’s rank correlation over the four different groups. With advanced age a slight but significant decrease in ESV (r=−0.41 for both ventricles, P<0.001) and EDV (r=−0.39 for left ventricle, r=−0.35 for right ventricle, P<0.001) were observed associated with a significant increase in left (r=0.28, P<0.001) and right (r=0.27, P<0.01) ventricular EF reaching a maximal increase in EF of +8.4% (P<0.001) for the left and +6.1% (P<0.01) for the right ventricle in the oldest compared to the youngest patient group. Left ventricular myocardial mass significantly decreased over the four different age groups (P<0.05). The aging process is associated with significant changes in left and right ventricular EF, ESV and EDV in subjects with no cardiac functional and structural abnormalities. These findings underline the importance of using age adapted values as standard of reference when evaluating CMR studies

  9. Targeting and function of the mitochondrial fission factor GDAP1 are dependent on its tail-anchor.

    Directory of Open Access Journals (Sweden)

    Konstanze M Wagner

    Full Text Available Proteins controlling mitochondrial dynamics are often targeted to and anchored into the mitochondrial outer membrane (MOM by their carboxyl-terminal tail-anchor domain (TA. However, it is not known whether the TA modulates protein function. GDAP1 is a mitochondrial fission factor with two neighboring hydrophobic domains each flanked by basic amino acids (aa. Here we define GDAP1 as TA MOM protein. GDAP1 carries a single transmembrane domain (TMD that is, together with the adjacent basic aa, critical for MOM targeting. The flanking N-terminal region containing the other hydrophobic domain is located in the cytoplasm. TMD sequence, length, and high hydrophobicity do not influence GDAP1 fission function if MOM targeting is maintained. The basic aa bordering the TMD in the cytoplasm, however, are required for both targeting of GDAP1 as part of the TA and GDAP1-mediated fission. Thus, this GDAP1 region contains critical overlapping motifs defining intracellular targeting by the TA concomitant with functional aspects.

  10. Regulation of Mitochondrial Function and Biogenesis in Cucumber (Cucumis sativus L.) Cotyledons during Early Seedling Growth 1

    Science.gov (United States)

    Hill, Steven A.; Grof, Christopher P. L.; Bryce, James H.; Leaver, Christopher J.

    1992-01-01

    The aim of this work was to characterize the respiratory metabolism of the greening cotyledons of cucumber (Cucumis sativus L.) during early seedling growth and to investigate how this is integrated with changes in mitochondrial biogenesis and function. In light-grown cotyledons, lipid mobilization extended from germination to 6 days postimbibition, reaching a maximum at 3 to 4 days postimbibition. The rate of dark oxygen uptake reached a maximum at 2 days postimbibition in dark-grown and 3 days postimbibition in light-grown cotyledons. Development of photosynthetic capacity occurred from 4 to 7 days postimbibition. In dark-grown cotyledons, lipid mobilization extended beyond 7 days postimbibition, and there was no greening or acquisition of photosynthetic competence. Measurements of mitochondrial function indicated that the respiratory capacity of the tissue changed such that during lipid mobilization there was a much greater capacity for the operation of the nondecarboxylating portion of the citric acid cycle (succinate to oxaloacetate), whereas during the development of photosynthetic function the activity of the remainder of the cycle (oxaloacetate to succinate) was induced. Comparison of the maximum capacities for mitochondrial substrate oxidations in vitro with the rates of in vivo substrate oxidations, predicted from the rate of lipid breakdown, indicated that mitochondria in this tissue operate at or below state 4 rates, suggesting limitation by both availability of ADP and substrate. PMID:16668884

  11. Fructose overfeeding in first-degree relatives of type 2 diabetic patients impacts energy metabolism and mitochondrial functions in skeletal muscle.

    Science.gov (United States)

    Seyssel, Kevin; Meugnier, Emmanuelle; Lê, Kim-Anne; Durand, Christine; Disse, Emmanuel; Blond, Emilie; Pays, Laurent; Nataf, Serge; Brozek, John; Vidal, Hubert; Tappy, Luc; Laville, Martine

    2016-12-01

    The aim of the study was to assess the effects of a high-fructose diet (HFrD) on skeletal muscle transcriptomic response in healthy offspring of patients with type 2 diabetes, a subgroup of individuals prone to metabolic disorders. Ten healthy normal weight first-degree relatives of type 2 diabetic patients were submitted to a HFrD (+3.5 g fructose/kg fat-free mass per day) during 7 days. A global transcriptomic analysis was performed on skeletal muscle biopsies combined with in vitro experiments using primary myotubes. Transcriptomic analysis highlighted profound effects on fatty acid oxidation and mitochondrial pathways supporting the whole-body metabolic shift with the preferential use of carbohydrates instead of lipids. Bioinformatics tools pointed out possible transcription factors orchestrating this genomic regulation, such as PPARα and NR4A2. In vitro experiments in human myotubes suggested an indirect action of fructose in skeletal muscle, which seemed to be independent from lactate, uric acid, or nitric oxide. This study shows therefore that a large cluster of genes related to energy metabolism, mitochondrial function, and lipid oxidation was downregulated after 7 days of HFrD, thus supporting the concept that overconsumption of fructose-containing foods could contribute to metabolic deterioration in humans. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Beneficial Effects of Ethanolic and Hexanic Rice Bran Extract on Mitochondrial Function in PC12 Cells and the Search for Bioactive Components

    Directory of Open Access Journals (Sweden)

    Stephanie Hagl

    2015-09-01

    Full Text Available Mitochondria are involved in the aging processes that ultimately lead to neurodegeneration and the development of Alzheimer’s disease (AD. A healthy lifestyle, including a diet rich in antioxidants and polyphenols, represents one strategy to protect the brain and to prevent neurodegeneration. We recently reported that a stabilized hexanic rice bran extract (RBE rich in vitamin E and polyphenols (but unsuitable for human consumption has beneficial effects on mitochondrial function in vitro and in vivo (doi:10.1016/j.phrs.2013.06.008, 10.3233/JAD-132084. To enable the use of RBE as food additive, a stabilized ethanolic extract has been produced. Here, we compare the vitamin E profiles of both extracts and their effects on mitochondrial function (ATP concentrations, mitochondrial membrane potential, mitochondrial respiration and mitochondrial biogenesis in PC12 cells. We found that vitamin E contents and the effects of both RBE on mitochondrial function were similar. Furthermore, we aimed to identify components responsible for the mitochondria-protective effects of RBE, but could not achieve a conclusive result. α-Tocotrienol and possibly also γ-tocotrienol, α-tocopherol and δ-tocopherol might be involved, but hitherto unknown components of RBE or a synergistic effect of various components might also play a role in mediating RBE’s beneficial effects on mitochondrial function.

  13. Vimar Is a Novel Regulator of Mitochondrial Fission through Miro.

    Directory of Open Access Journals (Sweden)

    Lianggong Ding

    2016-10-01

    Full Text Available As fundamental processes in mitochondrial dynamics, mitochondrial fusion, fission and transport are regulated by several core components, including Miro. As an atypical Rho-like small GTPase with high molecular mass, the exchange of GDP/GTP in Miro may require assistance from a guanine nucleotide exchange factor (GEF. However, the GEF for Miro has not been identified. While studying mitochondrial morphology in Drosophila, we incidentally observed that the loss of vimar, a gene encoding an atypical GEF, enhanced mitochondrial fission under normal physiological conditions. Because Vimar could co-immunoprecipitate with Miro in vitro, we speculated that Vimar might be the GEF of Miro. In support of this hypothesis, a loss-of-function (LOF vimar mutant rescued mitochondrial enlargement induced by a gain-of-function (GOF Miro transgene; whereas a GOF vimar transgene enhanced Miro function. In addition, vimar lost its effect under the expression of a constitutively GTP-bound or GDP-bound Miro mutant background. These results indicate a genetic dependence of vimar on Miro. Moreover, we found that mitochondrial fission played a functional role in high-calcium induced necrosis, and a LOF vimar mutant rescued the mitochondrial fission defect and cell death. This result can also be explained by vimar's function through Miro, because Miro's effect on mitochondrial morphology is altered upon binding with calcium. In addition, a PINK1 mutant, which induced mitochondrial enlargement and had been considered as a Drosophila model of Parkinson's disease (PD, caused fly muscle defects, and the loss of vimar could rescue these defects. Furthermore, we found that the mammalian homolog of Vimar, RAP1GDS1, played a similar role in regulating mitochondrial morphology, suggesting a functional conservation of this GEF member. The Miro/Vimar complex may be a promising drug target for diseases in which mitochondrial fission and fusion are dysfunctional.

  14. Normal serum matrix metalloproteinase-3 levels can be used to predict clinical remission and normal physical function in patients with rheumatoid arthritis.

    Science.gov (United States)

    Hattori, Yosuke; Kida, Daihei; Kaneko, Atsushi

    2017-09-22

    This study aimed to evaluate whether normal serum matrix metalloproteinase-3 (MMP-3) levels can be used to predict clinical remission and normal physical function at a single time point when treating patients with rheumatoid arthritis (RA) in daily practice settings. Subjects were all 1321 RA patients who were treated at our hospital. The accuracy of serum MMP-3 levels was larger than those of C-reactive protein (CRP) levels for predicting clinical remission [Simplified Disease Activity Index (SDAI) ≤ 3.3], normal function [Disability Index of the Health Assessment Questionnaire (HAQ-DI) ≤ 0.5], and both in clinical remission and with normal function (clinical remission + normal function) using receiver operating characteristic curve analysis. Serum MMP-3 levels were significantly correlated with CRP levels [r 0.229 (men), r 0.476 (women)] using Pearson's correlation coefficients. Among patients with normal CRP levels (n = 807), the percentage of patients in clinical remission, with normal function, and with clinical remission + normal function having normal serum MMP-3 levels was significantly higher than those with abnormal serum MMP-3 levels. In addition, among patients with the 28-point count Disease Activity Score-CRP (DAS28-CRP) remission (DAS28-CRP normal function, and with clinical remission + normal function having normal serum MMP-3 levels was significantly higher than those with abnormal serum MMP-3 levels. Our findings suggest that normal serum MMP-3 levels, in combination with CRP levels or disease activity, are useful for predicting clinical remission and normal physical function in patients with RA.

  15. Genotype-specific abnormalities in mitochondrial function associate with distinct profiles of energy metabolism and catecholamine content in pheochromocytoma and paraganglioma

    NARCIS (Netherlands)

    Rao, J.U.; Engelke, U.F.H.; Rodenburg, R.J.T.; Wevers, R.A.; Pacak, K.; Eisenhofer, G.; Qin, N.; Kusters, B.; Goudswaard, A.G.; Lenders, J.W.M.; Hermus, A.R.M.M.; Mensenkamp, A.R.; Kunst, H.P.M.; Sweep, F.C.; Timmers, H.J.L.M.

    2013-01-01

    PURPOSE: Pheochromocytomas and paragangliomas (PGL) are neuroendocrine tumors of sympathetic and parasympathetic paraganglia. This study investigated the relationships between genotype-specific differences in mitochondrial function and catecholamine content in PGL tumors. EXPERIMENTAL DESIGN:

  16. Clues to γ-secretase, huntingtin and Hirano body normal function using the model organism Dictyostelium discoideum

    Directory of Open Access Journals (Sweden)

    Myre Michael A

    2012-04-01

    Full Text Available Abstract Many neurodegenerative disorders, although related by their destruction of brain function, display remarkable cellular and/or regional pathogenic specificity likely due to a deregulated functionality of the mutant protein. However, neurodegenerative disease genes, for example huntingtin (HTT, the ataxins, the presenilins (PSEN1/PSEN2 are not simply localized to neurons but are ubiquitously expressed throughout peripheral tissues; it is therefore paramount to properly understand the earliest precipitating events leading to neuronal pathogenesis to develop effective long-term therapies. This means, in no unequivocal terms, it is crucial to understand the gene's normal function. Unfortunately, many genes are often essential for embryogenesis which precludes their study in whole organisms. This is true for HTT, the β-amyloid precursor protein (APP and presenilins, responsible for early onset Alzheimer's disease (AD. To better understand neurological disease in humans, many lower and higher eukaryotic models have been established. So the question arises: how reasonable is the use of organisms to study neurological disorders when the model of choice does not contain neurons? Here we will review the surprising, and novel emerging use of the model organism Dictyostelium discoideum, a species of soil-living amoeba, as a valuable biomedical tool to study the normal function of neurodegenerative genes. Historically, the evidence on the usefulness of simple organisms to understand the etiology of cellular pathology cannot be denied. But using an organism without a central nervous system to understand diseases of the brain? We will first introduce the life cycle of Dictyostelium, the presence of many disease genes in the genome and how it has provided unique opportunities to identify mechanisms of disease involving actin pathologies, mitochondrial disease, human lysosomal and trafficking disorders and host-pathogen interactions. Secondly, I will

  17. Treatment of human muscle cells with popular dietary supplements increase mitochondrial function and metabolic rate

    Directory of Open Access Journals (Sweden)

    Vaughan Roger A

    2012-11-01

    Full Text Available Abstract Background Obesity is a common pathology with increasing incidence, and is associated with increased mortality and healthcare costs. Several treatment options for obesity are currently available ranging from behavioral modifications to pharmaceutical agents. Many popular dietary supplements claim to enhance weight loss by acting as metabolic stimulators, however direct tests of their effect on metabolism have not been performed. Purpose This work identified the effects popular dietary supplements on metabolic rate and mitochondrial biosynthesis in human skeletal muscle cells. Methods Human rhabdomyosarcoma cells were treated with popular dietary supplements at varied doses for 24 hours. Peroxisome proliferator-activated receptor coactivator 1 alpha (PGC-1α, an important stimulator of mitochondrial biosynthesis, was quantified using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR. Mitochondrial content was measured using flow cytometry confirmed with confocal microscopy. Glycolytic metabolism was quantified by measuring extracellular acidification rate (ECAR and oxidative metabolism was quantified by measuring oxygen consumption rate (OCR. Total relative metabolism was quantified using WST-1 end point assay. Results Treatment of human rhabdomyosarcoma cells with dietary supplements OxyElite Pro (OEP or Cellucore HD (CHD induced PGC-1α leading to significantly increased mitochondrial content. Glycolytic and oxidative capacities were also significantly increased following treatment with OEP or CHD. Conclusion This is the first work to identify metabolic adaptations in muscle cells following treatment with popular dietary supplements including enhanced mitochondrial biosynthesis, and glycolytic, oxidative and total metabolism.

  18. Lactate and Pyruvate Are Major Sources of Energy for Stallion Sperm with Dose Effects on Mitochondrial Function, Motility, and ROS Production.

    Science.gov (United States)

    Darr, Christa R; Varner, Dickson D; Teague, Sheila; Cortopassi, Gino A; Datta, Sandipan; Meyers, Stuart A

    2016-08-01

    Stallion sperm rely primarily on oxidative phosphorylation for production of ATP used in sperm motility and metabolism. The objective of the study was to identify which substrates included in Biggers, Whitten, and Whittingham (BWW) media are key to optimal mitochondrial function through measurements of sperm motility parameters, mitochondrial oxygen consumption, and cellular reactive oxygen species (ROS) production. It was expected that mitochondrial substrates, pyruvate and lactate, would support sperm motility and mitochondrial function better than the glycolytic substrate, glucose, due to direct utilization within the mitochondria. Measurements were performed after incubation in modified BWW media with varying concentrations of lactate, pyruvate, and glucose. The effects of media and duration of incubation on sperm motility, ROS production, and oxygen consumption were determined using a linear mixed-effects model. Duplicate ejaculates from four stallions were used in three separate experiments to determine the effects of substrate availability and concentration on sperm motility and mitochondrial function and the relationship of oxygen consumption with cellular ROS production. The present results indicate that lactate and pyruvate are the most important sources of energy for stallion sperm motility and velocity, and elicit a dose-dependent response. Additionally, lactate and pyruvate are ideal for maximal mitochondrial function, as sperm in these media operate at a very high level of their bioenergetic capability due to the high rate of energy metabolism. Moreover, we found that addition of glucose to the media is not necessary for short-term storage of equine sperm, and may even result in reduction of mitochondrial function. Finally, we have confirmed that ROS production can be the result of mitochondrial dysfunction as well as intense mitochondrial activity. © 2016 by the Society for the Study of Reproduction, Inc.

  19. Functional dissection of the proton pumping modules of mitochondrial complex I.

    Directory of Open Access Journals (Sweden)

    Stefan Dröse

    2011-08-01

    Full Text Available Mitochondrial complex I, the largest and most complicated proton pump of the respiratory chain, links the electron transfer from NADH to ubiquinone to the pumping of four protons from the matrix into the intermembrane space. In humans, defects in complex I are involved in a wide range of degenerative disorders. Recent progress in the X-ray structural analysis of prokaryotic and eukaryotic complex I confirmed that the redox reactions are confined entirely to the hydrophilic peripheral arm of the L-shaped molecule and take place at a remarkable distance from the membrane domain. While this clearly implies that the proton pumping within the membrane arm of complex I is driven indirectly via long-range conformational coupling, the molecular mechanism and the number, identity, and localization of the pump-sites remains unclear. Here, we report that upon deletion of the gene for a small accessory subunit of the Yarrowia complex I, a stable subcomplex (nb8mΔ is formed that lacks the distal part of the membrane domain as revealed by single particle analysis. The analysis of the subunit composition of holo and subcomplex by three complementary proteomic approaches revealed that two (ND4 and ND5 of the three subunits with homology to bacterial Mrp-type Na(+/H(+ antiporters that have been discussed as prime candidates for harbouring the proton pumps were missing in nb8mΔ. Nevertheless, nb8mΔ still pumps protons at half the stoichiometry of the complete enzyme. Our results provide evidence that the membrane arm of complex I harbours two functionally distinct pump modules that are connected in series by the long helical transmission element recently identified by X-ray structural analysis.

  20. Characterization Theorems for Generalized Functionals of Discrete-Time Normal Martingale

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    Caishi Wang

    2015-01-01

    Full Text Available We aim at characterizing generalized functionals of discrete-time normal martingales. Let M=(Mnn∈N be a discrete-time normal martingale that has the chaotic representation property. We first construct testing and generalized functionals of M with an appropriate orthonormal basis for M’s square integrable functionals. Then we introduce a transform, called the Fock transform, for these functionals and characterize them via the transform. Several characterization theorems are established. Finally we give some applications of these characterization theorems. Our results show that generalized functionals of discrete-time normal martingales can be characterized only by growth condition, which contrasts sharply with the case of some continuous-time processes (e.g., Brownian motion, where both growth condition and analyticity condition are needed to characterize generalized functionals of those continuous-time processes.

  1. Chemical screening identifies ROCK as a target for recovering mitochondrial function in Hutchinson-Gilford progeria syndrome.

    Science.gov (United States)

    Kang, Hyun Tae; Park, Joon Tae; Choi, Kobong; Choi, Hyo Jei Claudia; Jung, Chul Won; Kim, Gyu Ree; Lee, Young-Sam; Park, Sang Chul

    2017-06-01

    Hutchinson-Gilford progeria syndrome (HGPS) constitutes a genetic disease wherein an aging phenotype manifests in childhood. Recent studies indicate that reactive oxygen species (ROS) play important roles in HGPS phenotype progression. Thus, pharmacological reduction in ROS levels has been proposed as a potentially effective treatment for patient with this disorder. In this study, we performed high-throughput screening to find compounds that could reduce ROS levels in HGPS fibroblasts and identified rho-associated protein kinase (ROCK) inhibitor (Y-27632) as an effective agent. To elucidate the underlying mechanism of ROCK in regulating ROS levels, we performed a yeast two-hybrid screen and discovered that ROCK1 interacts with Rac1b. ROCK activation phosphorylated Rac1b at Ser71 and increased ROS levels by facilitating the interaction between Rac1b and cytochrome c. Conversely, ROCK inactivation with Y-27632 abolished their interaction, concomitant with ROS reduction. Additionally, ROCK activation resulted in mitochondrial dysfunction, whereas ROCK inactivation with Y-27632 induced the recovery of mitochondrial function. Furthermore, a reduction in the frequency of abnormal nuclear morphology and DNA double-strand breaks was observed along with decreased ROS levels. Thus, our study reveals a novel mechanism through which alleviation of the HGPS phenotype is mediated by the recovery of mitochondrial function upon ROCK inactivation. © 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  2. Rescue of mitochondrial function in parkin-mutant fibroblasts using drug loaded PMPC-PDPA polymersomes and tubular polymersomes.

    Science.gov (United States)

    Yealland, G; Battaglia, G; Bandmann, O; Mortiboys, H

    2016-09-06

    Mutations in parkin cause autosomal recessive Parkinsonism and mitochondrial defects. A recent drug screen identified a class of steroid-like hydrophobic compounds able to rescue mitochondrial function in parkin-mutant fibroblasts. Whilst these possess therapeutic potential, the size and high hydrophobicity of some may limit their ability to penetrate the blood-brain barrier from systemic circulation, something that could be improved by novel drug formulations. In the present study, the steroid-like compounds Ursolic Acid (UA) and Ursocholanic Acid (UCA) were successfully encapsulated within nanoscopic polymersomes formed by poly(2-(methacryloyloxy)ethyl phosphorylcholine)-poly(2-di-isopropylamino)ethyl methacrylate) (PMPC-PDPA) and separated into spherical and tubular morphologies to assess the effects of nanoparticle mediated delivery on drug efficacy. Following incubation with either morphology, parkin-mutant fibroblasts demonstrated time and concentration dependent increases in intracellular ATP levels, resembling those resulting from treatment with nascent UA and UCA formulated in 0.1% DMSO, as used in the original drug screen. Empty PMPC-PDPA polymersomes did not alter physiological measures related to mitochondrial function or induce cytotoxicity. In combination with other techniques such as ligand functionalisation, PMPC-PDPA nanoparticles of well-defined morphology may prove a promising platform for tailoring the pharmacokinetic profile and organ specific bio-distribution of highly hydrophobic compounds. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  3. The Measurement of Reversible Redox Dependent Post-translational Modifications and Their Regulation of Mitochondrial and Skeletal Muscle Function

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Philip A.; Duan, Jicheng; Qian, Wei-Jun; Marcinek, David J.

    2015-11-25

    Mitochondrial oxidative stress is a common feature of skeletal myopathies across multiple conditions; however, the mechanism by which it contributes to skeletal muscle dysfunction remains controversial. Oxidative damage to proteins, lipids, and DNA has received the most attention, yet an important role for reversible redox post-translational modifications (PTMs) in pathophysiology is emerging. The possibility that these PTMs can exert dynamic control of muscle function implicates them as a mechanism contributing to skeletal muscle dysfunction in chronic disease. Herein, we discuss the significance of thiol-based redox dependent modifications to mitochondrial, myofibrillar and excitation-contraction (EC) coupling proteins with an emphasis on how these changes could alter skeletal muscle performance under chronically stressed conditions. A major barrier to a better mechanistic understanding of the role of reversible redox PTMs in muscle function is the technical challenges associated with accurately measuring the changes of site-specific redox PTMs. Here we will critically review current approaches with an emphasis on sample preparation artifacts, quantitation, and specificity. Despite these challenges, the ability to accurately quantify reversible redox PTMs is critical to understanding the mechanisms by which mitochondrial oxidative stress contributes to skeletal muscle dysfunction in chronic diseases.

  4. The measurement of reversible redox dependent post-translational modifications and their regulation of mitochondrial and skeletal muscle function

    Directory of Open Access Journals (Sweden)

    Philip A Kramer

    2015-11-01

    Full Text Available Mitochondrial oxidative stress is a common feature of skeletal myopathies across multiple conditions; however, the mechanism by which it contributes to skeletal muscle dysfunction remains controversial. Oxidative damage to proteins, lipids, and DNA has received the most attention, yet an important role for reversible redox post-translational modifications (PTMs in pathophysiology is emerging. The possibility that these PTMs can exert dynamic control of muscle function implicates them as a mechanism contributing to skeletal muscle dysfunction in chronic disease. Herein, we discuss the significance of thiol-based redox dependent modifications to mitochondrial, myofibrillar and excitation-contraction (EC coupling proteins with an emphasis on how these changes could alter skeletal muscle performance under chronically stressed conditions. A major barrier to a better mechanistic understanding of the role of reversible redox PTMs in muscle function is the technical challenges associated with accurately measuring the changes of site-specific redox PTMs. Here we will critically review current approaches with an emphasis on sample preparation artifacts, quantitation, and specificity. Despite these challenges, the ability to accurately quantify reversible redox PTMs is critical to understanding the mechanisms by which mitochondrial oxidative stress contributes to skeletal muscle dysfunction in chronic diseases.

  5. Combination of exercise training and diet restriction normalizes limited exercise capacity and impaired skeletal muscle function in diet-induced diabetic mice.

    Science.gov (United States)

    Suga, Tadashi; Kinugawa, Shintaro; Takada, Shingo; Kadoguchi, Tomoyasu; Fukushima, Arata; Homma, Tsuneaki; Masaki, Yoshihiro; Furihata, Takaaki; Takahashi, Masashige; Sobirin, Mochamad A; Ono, Taisuke; Hirabayashi, Kagami; Yokota, Takashi; Tanaka, Shinya; Okita, Koichi; Tsutsui, Hiroyuki

    2014-01-01

    Exercise training (EX) and diet restriction (DR) are essential for effective management of obesity and insulin resistance in diabetes mellitus. However, whether these interventions ameliorate the limited exercise capacity and impaired skeletal muscle function in diabetes patients remains unexplored. Therefore, we investigated the effects of EX and/or DR on exercise capacity and skeletal muscle function in diet-induced diabetic mice. Male C57BL/6J mice that were fed a high-fat diet (HFD) for 8 weeks were randomly assigned for an additional 4 weeks to 4 groups: control, EX, DR, and EX+DR. A lean group fed with a normal diet was also studied. Obesity and insulin resistance induced by a HFD were significantly but partially improved by EX or DR and completely reversed by EX+DR. Although exercise capacity decreased significantly with HFD compared with normal diet, it partially improved with EX and DR and completely reversed with EX+DR. In parallel, the impaired mitochondrial function and enhanced oxidative stress in the skeletal muscle caused by the HFD were normalized only by EX+DR. Although obesity and insulin resistance were completely reversed by DR with an insulin-sensitizing drug or a long-term intervention, the exercise capacity and skeletal muscle function could not be normalized. Therefore, improvement in impaired skeletal muscle function, rather than obesity and insulin resistance, may be an important therapeutic target for normalization of the limited exercise capacity in diabetes. In conclusion, a comprehensive lifestyle therapy of exercise and diet normalizes the limited exercise capacity and impaired muscle function in diabetes mellitus.

  6. Human, donkey and cow milk differently affects energy efficiency and inflammatory state by modulating mitochondrial function and gut microbiota.

    Science.gov (United States)

    Trinchese, Giovanna; Cavaliere, Gina; Canani, Roberto Berni; Matamoros, Sebastien; Bergamo, Paolo; De Filippo, Chiara; Aceto, Serena; Gaita, Marcello; Cerino, Pellegrino; Negri, Rossella; Greco, Luigi; Cani, Patrice D; Mollica, Maria Pina

    2015-11-01

    Different nutritional components are able, by modulating mitochondrial function and gut microbiota composition, to influence body composition, metabolic homeostasis and inflammatory state. In this study, we aimed to evaluate the effects produced by the supplementation of different milks on energy balance, inflammatory state, oxidative stress and antioxidant/detoxifying enzyme activities and to investigate the role of the mitochondrial efficiency and the gut microbiota in the regulation of metabolic functions in an animal model. We compared the intake of human milk, gold standard for infant nutrition, with equicaloric supplementation of donkey milk, the best substitute for newborns due to its nutritional properties, and cow milk, the primary marketed product. The results showed a hypolipidemic effect produced by donkey and human milk intake in parallel with enhanced mitochondrial activity/proton leakage. Reduced mitochondrial energy efficiency and proinflammatory signals (tumor necrosis factor α, interleukin-1 and lipopolysaccharide levels) were associated with a significant increase of antioxidants (total thiols) and detoxifying enzyme activities (glutathione-S-transferase, NADH quinone oxidoreductase) in donkey- and human milk-treated animals. The beneficial effects were attributable, at least in part, to the activation of the nuclear factor erythroid-2-related factor-2 pathway. Moreover, the metabolic benefits induced by human and donkey milk may be related to the modulation of gut microbiota. In fact, milk treatments uniquely affected the proportions of bacterial phyla and genera, and we hypothesized that the increased concentration of fecal butyrate in human and donkey milk-treated rats was related to the improved lipid and glucose metabolism and detoxifying activities. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Emerging drugs affecting skeletal muscle function and mitochondrial biogenesis - Potential implications for sports drug testing programs.

    Science.gov (United States)

    Thevis, Mario; Schänzer, Wilhelm

    2016-03-15

    A plethora of compounds potentially leading to drug candidates that affect skeletal muscle function and, more specifically, mitochondrial biogenesis, has been under (pre)clinical investigation for rare as well as more common diseases. Some of these compounds could be the object of misuse by athletes aiming at artificial and/or illicit and drug-facilitated performance enhancement, necessitating preventive and proactive anti-doping measures. Early warnings and the continuous retrieval and dissemination of information are crucial for sports drug testing laboratories as well as anti-doping authorities, as they assist in preparation of efficient doping control analytical strategies for potential future threats arising from new therapeutic developments. Scientific literature represents the main source of information, which yielded the herein discussed substances and therapeutic targets, which might become relevant for doping controls in the future. Where available, mass spectrometric data are presented, supporting the development of analytical strategies and characterization of compounds possibly identified in human sports drug testing samples. Focusing on skeletal muscle and mitochondrial biogenesis, numerous substances exhibiting agonistic or antagonistic actions on different cellular 'control centers' resulting in increased skeletal muscle mass, enhanced performance (as determined with laboratory animal models), and/or elevated amounts of mitochondria have been described. Substances of interest include agonists for REV-ERBα (e.g. SR9009, SR9011, SR10067, GSK4112), sirtuin 1 (e.g. SRT1720, SRT2104), adenosine monophosphate-activated protein kinase (AMPK, e.g. AICAR), peroxisome proliferator-activated receptor (PPAR)δ (e.g. GW1516, GW0742, L165041), and inhibitory/antagonistic agents targeting the methionine-folate cycle (MOTS-c), the general control non-derepressible 5 (GCN5) acetyl transferase (e.g. CPTH2, MB-3), myostatin (e.g. MYO-029), the myostatin receptor

  8. Mitochondrial DNA mutations provoke dominant inhibition of mitochondrial inner membrane fusion.

    Directory of Open Access Journals (Sweden)

    Cécile Sauvanet

    Full Text Available Mitochondria are highly dynamic organelles that continuously move, fuse and divide. Mitochondrial dynamics modulate overall mitochondrial morphology and are essential for the proper function, maintenance and transmission of mitochondria and mitochondrial DNA (mtDNA. We have investigated mitochondrial fusion in yeast cells with severe defects in oxidative phosphorylation (OXPHOS due to removal or various specific mutations of mtDNA. We find that, under fermentative conditions, OXPHOS deficient cells maintain normal levels of cellular ATP and ADP but display a reduced mitochondrial inner membrane potential. We demonstrate that, despite metabolic compensation by glycolysis, OXPHOS defects are associated to a selective inhibition of inner but not outer membrane fusion. Fusion inhibition was dominant and hampered the fusion of mutant mitochondria with wild-type mitochondria. Inhibition of inner membrane fusion was not systematically associated to changes of mitochondrial distribution and morphology, nor to changes in the isoform pattern of Mgm1, the major fusion factor of the inner membrane. However, inhibition of inner membrane fusion correlated with specific alterations of mitochondrial ultrastructure, notably with the presence of aligned and unfused inner membranes that are connected to two mitochondrial boundaries. The fusion inhibition observed upon deletion of OXPHOS related genes or upon removal of the entire mtDNA was similar to that observed upon introduction of point mutations in the mitochondrial ATP6 gene that are associated to neurogenic ataxia and retinitis pigmentosa (NARP or to maternally inherited Leigh Syndrome (MILS in humans. Our findings indicate that the consequences of mtDNA mutations may not be limited to OXPHOS defects but may also include alterations in mitochondrial fusion. Our results further imply that, in healthy cells, the dominant inhibition of fusion could mediate the exclusion of OXPHOS-deficient mitochondria from

  9. Novel Fusion Protein Targeting Mitochondrial DNA Improves Pancreatic Islet Functional Potency and Islet Transplantation Outcomes.

    Science.gov (United States)

    Danobeitia, Juan S; Chlebeck, Peter J; Shokolenko, Inna; Ma, Xiaobo; Wilson, Glenn; Fernandez, Luis A

    2017-11-01

    Long-term graft survival is an ongoing challenge in the field of islet transplantation. With the growing demand for transplantable organs, therapies to improve organ quality and reduce the incidence of graft dysfunction are of paramount importance. We evaluated the protective role of a recombinant DNA repair protein targeted to mitochondria (Exscien I-III), as a therapeutic agent using a rodent model of pancreatic islet transplantation. We first investigated the effect of therapy on isolated rat islets cultured with pro-inflammatory cytokines (interleukin-1 β, interferon γ, and tumor necrosis factor α) for 48 h and documented a significant reduction in apoptosis by flow cytometry, improved viability by immunofluorescence, and conserved functional potency in vitro and in vivo in Exscien I-III-treated islets. We then tested the effect of therapy in systemic inflammation using a rat model of donor brain death (BD) sustained for a 6-h period. Donor rats were allocated to 4 groups: (non-BD + vehicle, non-BD + Exscien I-III, BD + vehicle, and BD + Exscien I-III) and treated with Exscien I-III (4 mg/kg) or vehicle 30 min after BD induction. Sham (non-BD)-operated animals receiving either Exscien I-III or vehicle served as controls. Islets purified from BD + Exscien I-III-treated donors showed a significant increase in glucose-stimulated insulin release in vitro when compared to islets from vehicle-treated counterparts. In addition, donor treatment with Exscien I-III attenuated the effects of BD and significantly improved the functional potency of transplanted islets in vivo. Our data indicate that mitochondrially targeted antioxidant therapy is a novel strategy to protect pancreas and islet quality from the deleterious effects of cytokines in culture and during the inflammatory response associated with donation after BD. The potential for rapid translation into clinical practice makes Exscien I-III an attractive therapeutic option for the management of brain

  10. Mitochondrial quality control pathways as determinants of metabolic health

    NARCIS (Netherlands)

    Held, Ntsiki M.; Houtkooper, Riekelt H.

    2015-01-01

    Mitochondrial function is key for maintaining cellular health, while mitochondrial failure is associated with various pathologies, including inherited metabolic disorders and age-related diseases. In order to maintain mitochondrial quality, several pathways of mitochondrial quality control have

  11. The function and the role of the mitochondrial glycerol-3-phosphate dehydrogenase in mammalian tissues

    Czech Academy of Sciences Publication Activity Database

    Mráček, Tomáš; Drahota, Zdeněk; Houštěk, Josef

    2013-01-01

    Roč. 1827, č. 3 (2013), s. 401-410 ISSN 0005-2728 R&D Projects: GA ČR(CZ) GPP303/10/P227; GA MŠk(CZ) LL1204 Institutional support: RVO:67985823 Keywords : GPD2 gene * mitochondrial glycerophosphate dehydrogenace * ROS production * pathophysiology Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.829, year: 2013

  12. Role of Mitochondrial Reactive Oxygen Species in the Activation of Cellular Signals, Molecules, and Function

    DEFF Research Database (Denmark)

    Indo, Hiroko P.; Hawkins, Clare L; Nakanishi, Ikuo

    2017-01-01

    Mitochondria are a major source of intracellular energy and reactive oxygen species in cells, but are also increasingly being recognized as a controller of cell death. Here, we review evidence of signal transduction control by mitochondrial superoxide generation via the nuclear factor-κB (NF-κB) ...

  13. Impairment of mitochondrial function of rat hepatocytes by high fat diet and oxidative stress

    Czech Academy of Sciences Publication Activity Database

    Garnol, T.; Endlicher, R.; Kučera, O.; Drahota, Zdeněk; Červinková, Z.

    2014-01-01

    Roč. 63, č. 2 (2014), s. 271-274 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) LL1204 Grant - others:Univerzita Karlova(CZ) PRVOUK P37/02 Institutional support: RVO:67985823 Keywords : hepatocytes * high fat diet * mitochondrial activities * ROS Subject RIV: ED - Physiology Impact factor: 1.293, year: 2014

  14. Functional redundancy of mitochondrial enoyl-CoA isomerases in the oxidation of unsaturated fatty acids

    NARCIS (Netherlands)

    van Weeghel, Michel; te Brinke, Heleen; van Lenthe, Henk; Kulik, Wim; Minkler, Paul E.; Stoll, Maria S. K.; Sass, Jörn Oliver; Janssen, Uwe; Stoffel, Wilhelm; Schwab, K. Otfried; Wanders, Ronald J. A.; Hoppel, Charles L.; Houten, Sander M.

    2012-01-01

    Mitochondrial enoyl-CoA isomerase (ECI1) is an auxiliary enzyme involved in unsaturated fatty acid oxidation. In contrast to most of the other enzymes involved in fatty acid oxidation, a deficiency of ECI1 has yet to be identified in humans. We used wild-type (WT) and Eci1-deficient knockout (KO)

  15. Impaired Mitochondrial Respiratory Functions and Oxidative Stress in Streptozotocin-Induced Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Subbuswamy K. Prabu

    2011-05-01

    Full Text Available We have previously shown a tissue-specific increase in oxidative stress in the early stages of streptozotocin (STZ-induced diabetic rats. In this study, we investigated oxidative stress-related long-term complications and mitochondrial dysfunctions in the different tissues of STZ-induced diabetic rats (>15 mM blood glucose for 8 weeks. These animals showed a persistent increase in reactive oxygen and nitrogen species (ROS and RNS, respectively production. Oxidative protein carbonylation was also increased with the maximum effect observed in the pancreas of diabetic rats. The activities of mitochondrial respiratory enzymes ubiquinol: cytochrome c oxidoreductase (Complex III and cytochrome c oxidase (Complex IV were significantly decreased while that of NADH:ubiquinone oxidoreductase (Complex I and succinate:ubiquinone oxidoreductase (Complex II were moderately increased in diabetic rats, which was confirmed by the increased expression of the 70 kDa Complex II sub-unit. Mitochondrial matrix aconitase, a ROS sensitive enzyme, was markedly inhibited in the diabetic rat tissues. Increased expression of oxidative stress marker proteins Hsp-70 and HO-1 was also observed along with increased expression of nitric oxide synthase. These results suggest that mitochondrial respiratory complexes may play a critical role in ROS/RNS homeostasis and oxidative stress related changes in type 1 diabetes and may have implications in the etiology of diabetes and its complications.

  16. A YEAST SPECIFIC INSERTION AMIDST OBG FOLD IS CRITICAL FOR THE MITOCHONDRIAL FUNCTION OF Mtg2p IN SACCHAROMYCES CEREVISIAE

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    Upasana Mehra

    2017-06-01

    Full Text Available Protein expression in mitochondria is carried out by ribosomes that are distinct from their cytosolic counterpart. Mitochondrial ribosomes are made of individual proteins having distinct lineages: those with clear bacterial orthologues, those conserved in eukaryotes only and proteins that are species specific. MTG2 is the mitochondrial member of the universally conserved Obg family of GTPases in Saccharomyces cerevisiae which associates with and regulates mitochondrial large ribosomal subunit assembly. In this study we demonstrate that MTG2, in addition to the universally conserved OBG and GTPase domains, has an essential yeast specific insertion domain positioned within the N terminal OBG fold. Cells expressing mtg2∆201-294, deleted for the insertion domain are not able to support cellular respiration. In addition, we show that large stretches of amino acids can be inserted into MTG2 at the end of the yeast specific insertion domain and the OBG fold without perturbing its cellular functions, consistent with the insertion domain folding into a species specific protein binding platform.

  17. QiShenYiQi Pills, a Compound Chinese Medicine, Prevented Cisplatin Induced Acute Kidney Injury via Regulating Mitochondrial Function

    Directory of Open Access Journals (Sweden)

    Li Zhou

    2017-12-01

    Full Text Available Nephrotoxicity is a serious adverse effect of cisplatin chemotherapy that limits its clinical application, to deal with which no effective management is available so far. The present study was to investigate the potential protective effect of QiShenYiQi Pills (QSYQ, a compound Chinese medicine, against cisplatin induced nephrotoxicity in mice. Pretreatment with QSYQ significantly attenuated the cisplatin induced increase in plasma urea and creatinine, along with the histological damage, such as tubular necrosis, protein cast, and desquamation of epithelial cells, improved the renal microcirculation disturbance as indicated by renal blood flow, microvascular flow velocity, and the number of adherent leukocytes. Additionally, QSYQ prevented mitochondrial dysfunction by preventing the cisplatin induced downregulation of mitochondrial complex activity and the expression of NDUFA10, ATP5D, and Sirt3. Meanwhile, the cisplatin-increased renal thiobarbituric acid-reactive substances, caspase9, cleaved-caspase9, and cleaved-caspase3 were all diminished by QSYQ pretreatment. In summary, the pretreatment with QSYQ remarkably ameliorated the cisplatin induced nephrotoxicity in mice, possibly via the regulation of mitochondrial function, oxidative stress, and apoptosis.

  18. Changes in mitochondrial functioning with electromagnetic radiation of ultra high frequency as revealed by electron paramagnetic resonance methods.

    Science.gov (United States)

    Burlaka, Anatoly; Selyuk, Marina; Gafurov, Marat; Lukin, Sergei; Potaskalova, Viktoria; Sidorik, Evgeny

    2014-05-01

    To study the effects of electromagnetic radiation (EMR) of ultra high frequency (UHF) in the doses equivalent to the maximal permitted energy load for the staffs of the radar stations on the biochemical processes that occur in the cell organelles. Liver, cardiac and aorta tissues from the male rats exposed to non-thermal UHF EMR in pulsed and continuous modes were studied during 28 days after the irradiation by the electron paramagnetic resonance (EPR) methods including a spin trapping of superoxide radicals. The qualitative and quantitative disturbances in electron transport chain (ETC) of mitochondria are registered. A formation of the iron-nitrosyl complexes of nitric oxide (NO) radicals with the iron-sulphide (FeS) proteins, the decreased activity of FeS-protein N2 of NADH-ubiquinone oxidoreductase complex and flavo-ubisemiquinone growth combined with the increased rates of superoxide production are obtained. (i) Abnormalities in the mitochondrial ETC of liver and aorta cells are more pronounced for animals radiated in a pulsed mode; (ii) the alterations in the functioning of the mitochondrial ETC cause increase of superoxide radicals generation rate in all samples, formation of cellular hypoxia, and intensification of the oxide-initiated metabolic changes; and (iii) electron paramagnetic resonance methods could be used to track the qualitative and quantitative changes in the mitochondrial ETC caused by the UHF EMR.

  19. Overexpression of Chromosome 21 miRNAs May Affect Mitochondrial Function in the Hearts of Down Syndrome Fetuses

    Directory of Open Access Journals (Sweden)

    Antonella Izzo

    2017-01-01

    Full Text Available Dosage-dependent upregulation of most of chromosome 21 (Hsa21 genes has been demonstrated in heart tissues of fetuses with Down syndrome (DS. Also miRNAs might play important roles in the cardiac phenotype as they are highly expressed in the heart and regulate cardiac development. Five Hsa21 miRNAs have been well studied in the past: miR-99a-5p, miR-125b-2-5p, let-7c-5p, miR-155-5p, and miR-802-5p but few information is available about their expression in trisomic tissues. In this study, we evaluated the expression of these miRNAs in heart tissues from DS fetuses, showing that miR-99a-5p, miR-155-5p, and let-7c-5p were overexpressed in trisomic hearts. To investigate their role, predicted targets were obtained from different databases and cross-validated using the gene expression profiling dataset we previously generated for fetal hearts. Eighty-five targets of let-7c-5p, 33 of miR-155-5p, and 10 of miR-99a-5p were expressed in fetal heart and downregulated in trisomic hearts. As nuclear encoded mitochondrial genes were found downregulated in trisomic hearts and mitochondrial dysfunction is a hallmark of DS phenotypes, we put special attention to let-7c-5p and miR-155-5p targets downregulated in DS fetal hearts and involved in mitochondrial function. The let-7c-5p predicted target SLC25A4/ANT1 was identified as a possible candidate for both mitochondrial and cardiac anomalies.

  20. (p-ClPhSe)2Reduces Hepatotoxicity Induced by Monosodium Glutamate by Improving Mitochondrial Function in Rats.

    Science.gov (United States)

    Quines, Caroline B; Chagas, Pietro M; Hartmann, Diane; Carvalho, Nélson R; Soares, Félix A; Nogueira, Cristina W

    2017-09-01

    It is has been demonstrated that mitochondrial dysfunction, oxidative stress, and chronic inflammatory process are associated with progress of morbid obesity in human patients. For this reason, the searching for safe and effective antiobesity drugs has been the subject of intense research. In this context, the organic selenium compounds have attracted much attention due to their pharmacological properties, such as antihyperglycemic, antioxidant, and anti-inflammatory. The aim of this study was to evaluate the hepatoprotective action of p-chloro-diphenyl diselenide (p-ClPhSe) 2 , an organic selenium compound, in a model of obesity induced by monosodium glutamate (MSG) administration in rats. Wistar rats were treated during the first ten postnatal days with MSG (4 g/kg by subcutaneous injections) and received (p-ClPhSe) 2 (10 mg/kg, intragastrically) from 90th to 97th postnatal day. Mitochondrial function, purine content and the levels of proteins involved in apoptotic (poly [ADP-ribose] polymerase [PARP]) and inflammatory processes (inducible nitric oxide synthases [iNOS] and p38) were determined in the liver of rats. The present study, demonstrated that postnatal administration of MSG to male rats induced a mitochondrial dysfunction, accompanied by oxidative stress and an increase in the ADP levels, without altering the efficiency of phosphorylation in the liver of adult rats. Furthermore, the MSG administration also induces hepatotoxicity, through an increase in PARP, iNOS, and p38 levels. (p-ClPhSe) 2 treatment had beneficial effects against mitochondrial dysfunction, oxidative stress, and modulated protein markers of apoptosis and inflammation in the liver of MSG-treated rats. J. Cell. Biochem. 118: 2877-2886, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  1. Ulk1-mediated autophagy plays an essential role in mitochondrial remodeling and functional regeneration of skeletal muscle.

    Science.gov (United States)

    Call, Jarrod A; Wilson, Rebecca J; Laker, Rhianna C; Zhang, Mei; Kundu, Mondira; Yan, Zhen

    2017-06-01

    Autophagy is a conserved cellular process for degrading aggregate proteins and dysfunctional organelle. It is still debatable if autophagy and mitophagy (a specific process of autophagy of mitochondria) play important roles in myogenic differentiation and functional regeneration of skeletal muscle. We tested the hypothesis that autophagy is critical for functional regeneration of skeletal muscle. We first observed time-dependent increases (3- to 6-fold) of autophagy-related proteins (Atgs), including Ulk1, Beclin1, and LC3, along with reduced p62 expression during C2C12 differentiation, suggesting increased autophagy capacity and flux during myogenic differentiation. We then used cardiotoxin (Ctx) or ischemia-reperfusion (I/R) to induce muscle injury and regeneration and observed increases in Atgs between days 2 and 7 in adult skeletal muscle followed by increased autophagy flux after day 7 Since Ulk1 has been shown to be essential for mitophagy, we asked if Ulk1 is critical for functional regeneration in skeletal muscle. We subjected skeletal muscle-specific Ulk1 knockout mice (MKO) to Ctx or I/R. MKO mice had significantly impaired recovery of muscle strength and mitochondrial protein content post-Ctx or I/R. Imaging analysis showed that MKO mice have significantly attenuated recovery of mitochondrial network at 7 and 14 days post-Ctx. These findings suggest that increased autophagy protein and flux occur during muscle regeneration and Ulk1-mediated mitophagy is critical for recovery for the mitochondrial network and hence functional regeneration. Copyright © 2017 the American Physiological Society.

  2. Chronic Lymphocytic Leukemia B-Cell Normal Cellular Counterpart: Clues From a Functional Perspective.

    Science.gov (United States)

    Darwiche, Walaa; Gubler, Brigitte; Marolleau, Jean-Pierre; Ghamlouch, Hussein

    2018-01-01

    Chronic lymphocytic leukemia (CLL) is characterized by the clonal expansion of small mature-looking CD19+ CD23+ CD5+ B-cells that accumulate in the blood, bone marrow, and lymphoid organs. To date, no consensus has been reached concerning the normal cellular counterpart of CLL B-cells and several B-cell types have been proposed. CLL B-cells have remarkable phenotypic and gene expression profile homogeneity. In recent years, the molecular and cellular biology of CLL has been enriched by seminal insights that are leading to a better understanding of the natural history of the disease. Immunophenotypic and molecular approaches (including immunoglobulin heavy-chain variable gene mutational status, transcriptional and epigenetic profiling) comparing the normal B-cell subset and CLL B-cells provide some new insights into the normal cellular counterpart. Functional characteristics (including activation requirements and propensity for plasma cell differentiation) of CLL B-cells have now been investigated for 50 years. B-cell subsets differ substantially in terms of their functional features. Analysis of shared functional characteristics may reveal similarities between normal B-cell subsets and CLL B-cells, allowing speculative assignment of a normal cellular counterpart for CLL B-cells. In this review, we summarize current data regarding peripheral B-cell differentiation and human B-cell subsets and suggest possibilities for a normal cellular counterpart based on the functional characteristics of CLL B-cells. However, a definitive normal cellular counterpart cannot be attributed on the basis of the available data. We discuss the functional characteristics required for a cell to be logically considered to be the normal counterpart of CLL B-cells.

  3. Influence of heavy ions on cell survival, cytogenetic damage and mitochondrial function of human endothelial cells

    Science.gov (United States)

    Ritter, Sylvia; Helm, Alexander; Lee, Ryonfa; Pollet, Dieter; Durante, Marco

    There is increasing evidence that there is an elevated risk of cardiovascular disease among atomic bomb survivors and radiotherapy patients, typically developing with a long latency. However, essentially no information is available on the potential cardiovascular risks associated with space radiation, in particular heavy ions. To address this issue, we have chosen human umbilical vein endothelial cells (HUVEC) as a model system. Cells at an early passage number were irradiated with 0.1 to 4 Gy of either 9.8 MeV/u C-ions (LET=170 keV/µm), 91 MeV/u C-ions (LET=29 keV/µm) or 250 kV X-rays. Cells were regularly subcultured up to 40 days (20 population doublings) post-irradiation. Immediately after exposure cell inactivation was deter-mined by the colony forming assay. Furthermore, at selected time-points cytogenetic damage (formation of micronuclei in binucleated cells) and the mitochondrial membrane potential ΨM (flow cytometric analysis following JC-1 staining) were assessed. Measurement of the directly induced radiation damage showed that 9.8 MeV/u and 91 MeV/u C-ions were more effective than X-rays (i.e. about 3 and 2 times, respectively) with respect to cell inactivation or the in-duction of cytogenetic damage. At the subsequent days in the irradiated cultures the number of cells with micronuclei declined to the control level (3-5Altogether our data indicate that under the applied radiation conditions the integrity of mitochondria which play a significant role in the regulation of cardiovascular cell function is not impaired. With respect to directly induced genetic damage C-ions are more effective than X-rays as observed in other cell systems. If the effectiveness of charged particles for the occurrence of late chromosomal damage in endothelial cells is higher than that of sparsely ionizing radiation needs further clarification. The data obtained up to now indicate that sophisticated cytogenetic techniques have to be applied in order to draw any firm

  4. Serum nitrate levels as an index of endothelial function in pre-eclamsia and normal pregnancy.

    Science.gov (United States)

    Gupta, Rani; Maruthy, K N; Mhaskar, Arun M; Padmanabhan, Laxmi Devi

    2003-04-01

    The study was conducted in St. John's Medical College Hospital and Department of Physiology, with the aim of studying the serum nitrate levels in pre-eclampsia and normal pregnancy. The total number of subjects studied in various groups were 159, control (n = 55), first trimester (n = 13), second trimester normal (n = 42), second trimester pre-eclampsia/PET (n = 5), third trimester normal (n = 32), third trimester pre-eclampsia/PET (n = 12). The serum nitrate was measured by one step enzymatic assay using Nitrate reductase from Aspergillus species. The nitrate levels in the third trimester pre-eclamptic group was found to be significant lower (P = 0.02), as compared to normal subjects, however the renal functions were normal in all the subjects.

  5. Roles of interstitial fluid pH in diabetes mellitus: Glycolysis and mitochondrial function

    Science.gov (United States)

    Marunaka, Yoshinori

    2015-01-01

    The pH of body fluids is one the most important key factors regulating various cell function such as enzyme activity and protein-protein interaction via modification of its binding affinity. Therefore, to keep cell function normal, the pH of body fluids is maintained constant by various systems. Insulin resistance is one of the most important, serious factors making the body condition worse in diabetes mellitus. I have recently found that the pH of body (interstitial) fluids is lower in diabetes mellitus than that in non-diabetic control, and that the lowered pH is one of the causes producing insulin resistance. In this review article, I introduce importance of body (interstitial) fluid pH in regulation of body function, evidence on abnormal regulation of body fluid pH in diabetes mellitus, and relationship between the body fluid pH and insulin resistance. Further, this review proposes perspective therapies on the basis of regulation of body fluid pH including propolis (honeybee product) diet. PMID:25685283

  6. CCAAT/enhancer binding protein {beta} deletion increases mitochondrial function and protects mice from LXR-induced hepatic steatosis

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Shaikh M., E-mail: rmizanoor@hotmail.com [Department of Pediatrics, School of Medicine, University of Colorado Denver, Aurora, CO 80045 (United States); Choudhury, Mahua; Janssen, Rachel C.; Baquero, Karalee C. [Department of Pediatrics, School of Medicine, University of Colorado Denver, Aurora, CO 80045 (United States); Miyazaki, Makoto [Division of Renal Diseases and Hypertension, School of Medicine, University of Colorado Denver, Aurora, CO 80045 (United States); Friedman, Jacob E. [Department of Pediatrics, School of Medicine, University of Colorado Denver, Aurora, CO 80045 (United States); Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Denver, Aurora, CO 80045 (United States)

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer LXR agonist activation increases liver TG accumulation by increasing lipogenesis. Black-Right-Pointing-Pointer C/EBP{beta}{sup -/-} mouse prevents LXR activation-mediated induction of hepatic lipogenesis. Black-Right-Pointing-Pointer C/EBP{beta} deletion increases mitochondrial transport chain function. Black-Right-Pointing-Pointer Beneficial effects of LXR activation on liver cholesterol metabolism did not change. Black-Right-Pointing-Pointer C/EBP{beta} inhibition might have important therapeutic potential. -- Abstract: Drugs designed specifically to activate liver X receptors (LXRs) have beneficial effects on lowering cholesterol metabolism and inflammation but unfortunately lead to severe hepatic steatosis. The transcription factor CCAAT/enhancer binding protein beta (C/EBP{beta}) is an important regulator of liver gene expression but little is known about its involvement in LXR-based steatosis and cholesterol metabolism. The present study investigated the role of C/EBP{beta} expression in LXR agonist (T0901317)-mediated alteration of hepatic triglyceride (TG) and lipogenesis in mice. C/EBP{beta} deletion in mice prevented LXR agonist-mediated induction of lipogenic gene expression in liver in conjunction with significant reduction of liver TG accumulation. Surprisingly, C/EBP{beta}{sup -/-} mice showed a major increase in liver mitochondrial electron chain function compared to WT mice. Furthermore, LXR activation in C/EBP{beta}{sup -/-} mice increased the expression of liver ATP-binding cassette transporter ABCG1, a gene implicated in cholesterol efflux and reducing blood levels of total and LDL-cholesterol. Together, these findings establish a central role for C/EBP{beta} in the LXR-mediated steatosis and mitochondrial function, without impairing the influence of LXR activation on lowering LDL and increasing HDL-cholesterol. Inactivation of C/EBP{beta} might therefore be an important therapeutic strategy to prevent LXR

  7. CCAAT/enhancer binding protein β deletion increases mitochondrial function and protects mice from LXR-induced hepatic steatosis

    International Nuclear Information System (INIS)

    Rahman, Shaikh M.; Choudhury, Mahua; Janssen, Rachel C.; Baquero, Karalee C.; Miyazaki, Makoto; Friedman, Jacob E.

    2013-01-01

    Highlights: ► LXR agonist activation increases liver TG accumulation by increasing lipogenesis. ► C/EBPβ −/− mouse prevents LXR activation-mediated induction of hepatic lipogenesis. ► C/EBPβ deletion increases mitochondrial transport chain function. ► Beneficial effects of LXR activation on liver cholesterol metabolism did not change. ► C/EBPβ inhibition might have important therapeutic potential. -- Abstract: Drugs designed specifically to activate liver X receptors (LXRs) have beneficial effects on lowering cholesterol metabolism and inflammation but unfortunately lead to severe hepatic steatosis. The transcription factor CCAAT/enhancer binding protein beta (C/EBPβ) is an important regulator of liver gene expression but little is known about its involvement in LXR-based steatosis and cholesterol metabolism. The present study investigated the role of C/EBPβ expression in LXR agonist (T0901317)-mediated alteration of hepatic triglyceride (TG) and lipogenesis in mice. C/EBPβ deletion in mice prevented LXR agonist-mediated induction of lipogenic gene expression in liver in conjunction with significant reduction of liver TG accumulation. Surprisingly, C/EBPβ −/− mice showed a major increase in liver mitochondrial electron chain function compared to WT mice. Furthermore, LXR activation in C/EBPβ −/− mice increased the expression of liver ATP-binding cassette transporter ABCG1, a gene implicated in cholesterol efflux and reducing blood levels of total and LDL-cholesterol. Together, these findings establish a central role for C/EBPβ in the LXR-mediated steatosis and mitochondrial function, without impairing the influence of LXR activation on lowering LDL and increasing HDL-cholesterol. Inactivation of C/EBPβ might therefore be an important therapeutic strategy to prevent LXR activation-mediated adverse effects on liver TG metabolism without disrupting its beneficial effects on cholesterol metabolism.

  8. Validation of MCDS by comparison of predicted with experimental velocity distribution functions in rarefied normal shocks

    Science.gov (United States)

    Pham-Van-diep, Gerald C.; Erwin, Daniel A.

    1989-01-01

    Velocity distribution functions in normal shock waves in argon and helium are calculated using Monte Carlo direct simulation. These are compared with experimental results for argon at M = 7.18 and for helium at M = 1.59 and 20. For both argon and helium, the variable-hard-sphere (VHS) model is used for the elastic scattering cross section, with the velocity dependence derived from a viscosity-temperature power-law relationship in the way normally used by Bird (1976).

  9. Clinical usefulness of myocardial iodine-123-15-(p-iodophenyl)-3(R,S)-methyl-pentadecanoic acid distribution abnormality in patients with mitochondrial encephalomyopathy based on normal data file in bull's-eye polar map

    International Nuclear Information System (INIS)

    Takahashi, Nobukazu; Mitani, Isao; Sumita, Shinichi

    1998-01-01

    Visual interpretation of iodine-123-beta-15-(p-iodophenyl)-3(R,S)-methyl-pentadecanoic acid ( 123 I-BMIPP) myocardial images cannot easily detect mild reduction in tracer uptake. Objective assessment of myocardial 123 I-BMIPP maldistributions at rest was attempted using a bull's-eye map and its normal data file for detecting myocardial damage in patients with mitochondrial encephalomyopathy. Six patients, two with Kearns-Sayre syndrome and four with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS), and 10 normal subjects were studied. Fractional myocardial uptake of 1 23 I-BMIPP was also measured by dynamic static imaging to assess the global myocardial free fatty acid. These data were compared with the cardiothoracic ratio measured by chest radiography and left ventricular ejection fraction assessed by echocardiography. Abnormal cardiothoracic ratio and lower ejection fraction were detected in only one patient with Kearns-Sayre syndrome. Abnormal fractional myocardial uptake was detected in two patients (1.61%, 1.91%), whereas abnormal regional 123 I-BMIPP uptake assessed by the bull's-eye map was detected in five patients (83%). All patients showed abnormal uptake in the anterior portion, and one showed progressive atrioventricular conduction abnormality and systolic dysfunction with extended 123 I-BMIPP abnormal uptake. The results suggest that assessment based on the normal data file in a bull's-eye polar map is clinically useful for detection of myocardial damage in patients with mitochondrial encephalomyopathy. (author)

  10. Renal function maturation in children: is normalization to surface area valid?

    International Nuclear Information System (INIS)

    Rutland, M.D.; Hassan, I.M.; Que, L.

    1999-01-01

    Full text: Gamma camera DTPA renograms were analysed to measure renal function by the rate at which the kidneys took up tracer from the blood. This was expressed either directly as the fractional uptake rate (FUR), which is not related to body size, or it was converted to a camera-based GFR by the formula GFR blood volume x FUR, and this GFR was normalized to a body surface area of 1.73 m2. Most of the patients studied had one completely normal kidney, and one kidney with reflux but normal function and no large scars. The completely normal kidneys contributed, on average, 50% of the total renal function. The results were considered in age bands, to display the effect of age on renal function. The camera-GFR measurements showed the conventional results of poor renal function in early childhood, with a slow rise to near-adult values by the age of 2 years, and somewhat low values throughout childhood. The uptake values showed a different pattern, with renal function rising to adult equivalent values by the age of 4 months, and with children having better renal function than adults throughout most of their childhood. The standard deviations expressed as coefficients of variation (CV) were smaller for the FUR technique than the GFR (Wilcoxon rank test, P < 0.01). These results resemble recent published measurements of absolute DMSA uptake, which are also unrelated to body size and show early renal maturation. The results also suggest that the reason children have lower serum creatinine levels than adults is that they have better renal function. If this were confirmed, it would raise doubts about the usefulness of normalizing renal function to body surface area in children

  11. Downregualtion of dynamin-related protein 1 attenuates glutamate-induced excitotoxicity via regulating mitochondrial function in a calcium dependent manner in HT22 cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chi; Yuan, Xian-rui; Li, Hao-yu; Zhao, Zi-jin; Liao, Yi-wei; Wang, Xiang-yu; Su, Jun; Sang, Shu-shan; Liu, Qing, E-mail: xiangyaliuqing@163.com

    2014-01-03

    Highlights: •Downregulation of Drp-1 attenuates glutamate-induced excitotoxicity. •Downregulation of Drp-1 inhibits glutamate-induced apoptosis. •Downregulation of Drp-1 reduces glutamate-induced mitochondrial dysfunction. •Downregulation of Drp-1 preserves intracellular calcium homeostasis. -- Abstract: Glutamate-mediated excitotoxicity is involved in many acute and chronic brain diseases. Dynamin related protein 1 (Drp-1), one of the GTPase family of proteins that regulate mitochondrial fission and fusion balance, is associated with apoptotic cell death in cancer and neurodegenerative diseases. Here we investigated the effect of downregulating Drp-1 on glutamate excitotoxicity-induced neuronal injury in HT22 cells. We found that downregulation of Drp-1 with specific small interfering RNA (siRNA) increased cell viability and inhibited lactate dehydrogenase (LDH) release after glutamate treatment. Downregulation of Drp-1 also inhibited an increase in the Bax/Bcl-2 ratio and cleavage of caspase-9 and caspase-3. Drp-1 siRNA transfection preserved the mitochondrial membrane potential (MMP), reduced cytochrome c release, enhanced ATP production, and partly prevented mitochondrial swelling. In addition, Drp-1 knockdown attenuated glutamate-induced increases of cytoplasmic and mitochondrial Ca{sup 2+}, and preserved the mitochondrial Ca{sup 2+} buffering capacity after excitotoxicity. Taken together, these results suggest that downregulation of Drp-1 protects HT22 cells against glutamate-induced excitatory damage, and this neuroprotection may be dependent at least in part on the preservation of mitochondrial function through regulating intracellular calcium homeostasis.

  12. NAD⁺ repletion improves mitochondrial and stem cell function and enhances life span in mice.

    Science.gov (United States)

    Zhang, Hongbo; Ryu, Dongryeol; Wu, Yibo; Gariani, Karim; Wang, Xu; Luan, Peiling; D'Amico, Davide; Ropelle, Eduardo R; Lutolf, Matthias P; Aebersold, Ruedi; Schoonjans, Kristina; Menzies, Keir J; Auwerx, Johan

    2016-06-17

    Adult stem cells (SCs) are essential for tissue maintenance and regeneration yet are susceptible to senescence during aging. We demonstrate the importance of the amount of the oxidized form of cellular nicotinamide adenine dinucleotide (NAD(+)) and its effect on mitochondrial activity as a pivotal switch to modulate muscle SC (MuSC) senescence. Treatment with the NAD(+) precursor nicotinamide riboside (NR) induced the mitochondrial unfolded protein response and synthesis of prohibitin proteins, and this rejuvenated MuSCs in aged mice. NR also prevented MuSC senescence in the mdx (C57BL/10ScSn-Dmd(mdx)/J) mouse model of muscular dystrophy. We furthermore demonstrate that NR delays senescence of neural SCs and melanocyte SCs and increases mouse life span. Strategies that conserve cellular NAD(+) may reprogram dysfunctional SCs and improve life span in mammals. Copyright © 2016, American Association for the Advancement of Science.

  13. Oxidation of intramyocellular lipids is dependent on mitochondrial function and the availability of extracellular fatty acids

    DEFF Research Database (Denmark)

    Corpeleijn, Eva; Hessvik, Nina P; Bakke, Siril S

    2010-01-01

    Obesity and insulin resistance are related to both enlarged intramyocellular triacylglycerol stores and accumulation of lipid intermediates. We investigated how lipid overflow can change the oxidation of intramyocellular lipids (ICL(OX)) and intramyocellular lipid storage (ICL). These experiments...... microM) reduced ICL(OX) by 37%. No differences in total lipolysis were observed between low and high OA availability. Uncoupling with FCCP restored ICL(OX) to basal levels during high OA availability. Mitochondrial mass was positively related to ICL(OX), but only in myotubes from lean individuals....... In all, a lower mitochondrial mass and lower ICL(OX) were related to a higher cell-associated OA accumulation. Second, myotubes established from obese T2D individuals showed reduced ICL(OX). ICL(OX) remained lower during uncoupling (P

  14. Mechanisms underlying skeletal muscle insulin resistance induced by fatty acids: importance of the mitochondrial function

    Directory of Open Access Journals (Sweden)

    Martins Amanda R

    2012-02-01

    Full Text Available Abstract Insulin resistance condition is associated to the development of several syndromes, such as obesity, type 2 diabetes mellitus and metabolic syndrome. Although the factors linking insulin resistance to these syndromes are not precisely defined yet, evidence suggests that the elevated plasma free fatty acid (FFA level plays an important role in the development of skeletal muscle insulin resistance. Accordantly, in vivo and in vitro exposure of skeletal muscle and myocytes to physiological concentrations of saturated fatty acids is associated with insulin resistance condition. Several mechanisms have been postulated to account for fatty acids-induced muscle insulin resistance, including Randle cycle, oxidative stress, inflammation and mitochondrial dysfunction. Here we reviewed experimental evidence supporting the involvement of each of these propositions in the development of skeletal muscle insulin resistance induced by saturated fatty acids and propose an integrative model placing mitochondrial dysfunction as an important and common factor to the other mechanisms.

  15. Rev1 contributes to proper mitochondrial function via the PARP-NAD(+)-SIRT1-PGC1 alpha axis

    DEFF Research Database (Denmark)

    Fakouri, Nima Borhan; Durhuus, Jon Ambaek; Regnell, Christine Elisabeth

    2017-01-01

    (ADP) ribose polymerase 1 (PARP1) activity, low endogenous NAD+, low expression of SIRT1 and PGC1α and low adenosine monophosphate (AMP)-activated kinase (AMPK) activity. We conclude that replication stress via Rev1-deficiency contributes to metabolic stress caused by compromized mitochondrial function via...... the PARP-NAD+-SIRT1-PGC1α axis.......- and double-stranded DNA breaks (SSBs and DSBs), and single-stranded gaps can block progression of the DNA replication fork, causing replicative stress and/or cell cycle arrest. However, translesion synthesis (TLS) DNA polymerases, such as Rev1, have the ability to bypass some DNA lesions, which can...

  16. The Application of Normal Stress Reduction Function in Tilt Tests for Different Block Shapes

    Science.gov (United States)

    Kim, Dong Hyun; Gratchev, Ivan; Hein, Maw; Balasubramaniam, Arumugam

    2016-08-01

    This paper focuses on the influence of the shapes of rock cores, which control the sliding or toppling behaviours in tilt tests for the estimation of rock joint roughness coefficients (JRC). When the JRC values are estimated by performing tilt tests, the values are directly proportional to the basic friction of the rock material and the applied normal stress on the sliding planes. Normal stress obviously varies with the shape of the sliding block, and the basic friction angle is also affected by the sample shapes in tilt tests. In this study, the shapes of core blocks are classified into three representative shapes and those are created using plaster. Using the various shaped artificial cores, a set of tilt tests is carried out to identify the shape influences on the normal stress and the basic friction angle in tilt tests. The test results propose a normal stress reduction function to estimate the normal stress for tilt tests according to the sample shapes based on Barton's empirical equation. The proposed normal stress reduction functions are verified by tilt tests using artificial plaster joints and real rock joint sets. The plaster joint sets are well matched and cast in detailed printed moulds using a 3D printing technique. With the application of the functions, the obtained JRC values from the tilt tests using the plaster samples and the natural rock samples are distributed within a reasonable JRC range when compared with the measured values.

  17. Endonuclease G is a novel determinant of cardiac hypertrophy and mitochondrial function

    Czech Academy of Sciences Publication Activity Database

    McDermott-Roe, Ch.; Ye, J.; Ahmed, R.; Sun, X. M.; Serafín, A.; Ware, J.; Bottolo, L.; Muckett, P.; Caňas, X.; Zhang, J.; Rowe, G. C.; Buchan, R.; Lu, H.; Braithwaite, A.; Mancini, M.; Hauton, D.; Martí, R.; García-Arumí, E.; Hubner, N.; Jacob, H.; Serikawa, T.; Zídek, Václav; Papoušek, František; Kolář, František; Cardona, M.; Ruiz-Meana, M.; García-Dorado, D.; Comella, J. X.; Felkin, L. E.; Barton, P. J. R.; Arany, Z.; Pravenec, Michal; Petretto, E.; Sanchis, D.; Cook, S.A.

    2011-01-01

    Roč. 478, č. 7367 (2011), s. 114-118 ISSN 0028-0836 R&D Projects: GA MŠk(CZ) 1M0520; GA ČR(CZ) GA301/08/0166 Institutional research plan: CEZ:AV0Z50110509 Keywords : left ventricular hypertrophy * endonuclease G * mitochondrial dysfunction Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 36.280, year: 2011

  18. Centella asiatica modulates antioxidant and mitochondrial pathways and improves cognitive function in mice.

    Science.gov (United States)

    Gray, Nora E; Harris, Christopher J; Quinn, Joseph F; Soumyanath, Amala

    2016-03-02

    This study investigates the cognitive enhancing effects of the plant Centella asiatica which is widely used Ayurvedic and traditional Chinese medicine. The goal of this study was to determine the effects of a water extract of the medicinal plant Centella asiatica (CAW) on cognitive ability as well as mitochondrial and antioxidant response pathways in vivo. Old and young C57BL/6 mice were treated with CAW (2mg/mL) in their drinking water. Learning and memory was assessed using Morris Water Maze (MWM) and then tissue was collected and gene expression analyzed. CAW improved performance in the MWM in aged animals and had a modest effect on the performance of young animals. CAW also increased the expression of mitochondrial and antioxidant response genes in the brain and liver of both young and old animals. Expression of synaptic markers was also increased in the hippocampus and frontal cortex, but not in the cerebellum of CAW-treated animals. These data indicate a cognitive enhancing effect of CAW in healthy mice. The gene expression changes caused by CAW suggest a possible effect on mitochondrial biogenesis, which in conjunction with activation of antioxidant response genes could contribute to cognitive improvement. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  19. Alcohol alters hepatic FoxO1, p53, and mitochondrial SIRT5 deacetylation function

    International Nuclear Information System (INIS)

    Lieber, Charles S.; Leo, Maria Anna; Wang, Xiaolei; DeCarli, Leonore M.

    2008-01-01

    Chronic alcohol consumption affects the gene expression of a NAD-dependent deacetylase Sirtuis 1 (SIRT1) and the peroxisome proliferator-activated receptor-γ coactivator1α (PGC-1α). Our aim was to verify that it also alters the forkhead (FoxO1) and p53 transcription factor proteins, critical in the hepatic response to oxidative stress and regulated by SIRT1 through its deacetylating capacity. Accordingly, rats were pair-fed the Lieber-DeCarli alcohol-containing liquid diets for 28 days. Alcohol increased hepatic mRNA expression of FoxO1 (p = 0.003) and p53 (p = 0.001) while corresponding protein levels remained unchanged. However phospho-FoxO1 and phospho-Akt (protein kinase) were both decreased by alcohol consumption (p = 0.04 and p = 0.02, respectively) while hepatic p53 was found hyperacetylated (p = 0.017). Furthermore, mitochondrial SIRT5 was reduced (p = 0.0025), and PGC-1α hyperacetylated (p = 0.027), establishing their role in protein modification. Thus, alcohol consumption disrupts nuclear-mitochondrial interactions by post-translation protein modifications, which contribute to alteration of mitochondrial biogenesis through the newly discovered reduction of SIRT5

  20. A hypertension-associated mitochondrial DNA mutation alters the tertiary interaction and function of tRNALeu(UUR).

    Science.gov (United States)

    Zhou, Mi; Wang, Meng; Xue, Ling; Lin, Zhi; He, Qiufen; Shi, Wenwen; Chen, Yaru; Jin, Xiaofen; Li, Haiying; Jiang, Pingping; Guan, Min-Xin

    2017-08-25

    Several mitochondrial tRNA mutations have been associated with hypertension, but their pathophysiology remains poorly understood. In this report, we identified a novel homoplasmic 3253T→C mutation in the mitochondrial tRNA Leu(UUR) gene in a Han Chinese family with maternally inherited hypertension. The m.3253T→C mutation affected a highly conserved uridine at position 22 at the D-stem of tRNA Leu(UUR) , introducing a G-C base pairing (G13-C22) at the D-stem and a tertiary base pairing (C22-G46) between the D-stem and the variable loop. We therefore hypothesized that the m.3253T→C mutation altered both the structure and function of tRNA Leu(UUR) Using cytoplasmic hybrid (cybrid) cell lines derived from this Chinese family, we demonstrated that the m.3253T→C mutation perturbed the conformation and stability of tRNA Leu(UUR) , as suggested by faster electrophoretic mobility of mutated tRNA relative to the wild-type molecule. Northern blot analysis revealed an ∼45% decrease in the steady-state level of tRNA Leu(UUR) in the mutant cell lines carrying the m.3253T→C mutation, as compared with control cell lines. Moreover, an ∼35% reduction in aminoacylation efficiency of tRNA Leu(UUR) was observed in the m.3253T→C mutant cells. These alterations in tRNA Leu(UUR) metabolism impaired mitochondrial translation, especially for those polypeptides with a high proportion of Leu(UUR) codons, such as ND6. Furthermore, we demonstrated that the m.3253T→C mutation decreased the activities of mitochondrial complexes I and V, markedly diminished mitochondrial ATP levels and membrane potential, and increased the production of reactive oxygen species in the cells. In conclusion, our findings may provide new insights into the pathophysiology of maternally inherited hypertension. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. Curcumin restores mitochondrial functions and decreases lipid peroxidation in liver and kidneys of diabetic db/db mice

    Directory of Open Access Journals (Sweden)

    María G Soto-Urquieta

    2014-01-01

    Full Text Available BACKGROUND: Nitrosative and oxidative stress play a key role in obesity and diabetes-related mitochondrial dysfunction. The objective was to investigate the effect of curcumin treatment on state 3 and 4 oxygen consumption, nitric oxide (NO synthesis, ATPase activity and lipid oxidation in mitochondria isolated from liver and kidneys of diabetic db/db mice. RESULTS: Hyperglycaemia increased oxygen consumption and decreased NO synthesis in liver mitochondria isolated from diabetic mice relative to the control mice. In kidney mitochondria, hyperglycaemia increased state 3 oxygen consumption and thiobarbituric acid-reactive substances (TBARS levels in diabetic mice relative to control mice. Interestingly, treating db/db mice with curcumin improved or restored these parameters to normal levels; also curcumin increased liver mitochondrial ATPase activity in db/db mice relative to untreated db/db mice. CONCLUSIONS: These findings suggest that hyperglycaemia modifies oxygen consumption rate, NO synthesis and increases TBARS levels in mitochondria from the liver and kidneys of diabetic mice, whereas curcumin may have a protective role against these alterations.

  2. Role of oxidants/inflammation in declining renal function in chronic kidney disease and normal aging.

    Science.gov (United States)

    Vlassara, Helen; Torreggiani, Massimo; Post, James B; Zheng, Feng; Uribarri, Jaime; Striker, Gary E

    2009-12-01

    Oxidant stress (OS) and inflammation increase in normal aging and in chronic kidney disease (CKD), as observed in human and animal studies. In cross-sectional studies of the US population, these changes are associated with a decrease in renal function, which is exhibited by a significant proportion of the population. However, since many normal adults have intact renal function, and longitudinal studies show that some persons maintain normal renal function with age, the link between OS, inflammation, and renal decline is not clear. In aging mice, greater oxidant intake is associated with increased age-related CKD and mortality, which suggests that interventions that reduce OS and inflammation may be beneficial for older individuals. Both OS and inflammation can be readily lowered in normal subjects and patients with CKD stage 3-4 by a simple dietary modification that lowers intake and results in reduced serum and tissue levels of advanced glycation end products. Diabetic patients, including those with microalbuminuria, have a decreased ability to metabolize and excrete oxidants prior to observable changes in serum creatinine. Thus, OS and inflammation may occur in the diabetic kidney at an early time. We review the evidence that oxidants in the diet directly lead to increased serum levels of OS and inflammatory mediators in normal aging and in CKD. We also discuss a simple dietary intervention that helps reduce OS and inflammation, an important and achievable therapeutic goal for patients with CKD and aging individuals with reduced renal function.

  3. Normal pancreatic exocrine function does not exclude MRI/MRCP chronic pancreatitis findings.

    Science.gov (United States)

    Alkaade, Samer; Cem Balci, Numan; Momtahen, Amir Javad; Burton, Frank

    2008-09-01

    Abnormal pancreatic function tests have been reported to precede the imaging findings of chronic pancreatitis. Magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP) is increasingly accepted as the primary imaging modality for the detection of structural changes of early mild chronic pancreatitis. The aim of this study was to evaluate MRI/MRCP findings in patients with symptoms consistent with chronic pancreatitis who have normal Secretin Endoscopic Pancreatic Function test. A retrospective study of 32 patients referred for evaluation of chronic abdominal pain consistent with chronic pancreatitis and reported normal standard abdominal imaging (ultrasound, computed tomography, or MRI). All patients underwent Secretin Endoscopic Pancreatic Function testing and pancreatic MRI/MRCP at our institution. We reviewed the MRI/MRCP images in patients who had normal Secretin Endoscopic Pancreatic Function testing. MRI/MRCP images were assessed for pancreatic duct morphology, gland size, parenchymal signal and morphology, and arterial contrast enhancement. Of the 32 patients, 23 had normal Secretin Endoscopic Pancreatic Function testing, and 8 of them had mild to marked spectrum of abnormal MRI/MRCP findings that were predominantly focal. Frequencies of the findings were as follows: pancreatic duct stricture (n=3), pancreatic duct dilatation (n=3), side branch ectasia (n=4), atrophy (n=5), decreased arterial enhancement (n=5), decreased parenchymal signal (n=1), and cavity formation (n=1). The remaining15 patients had normal pancreatic structure on MRI/MRCP. Normal pancreatic function testing cannot exclude abnormal MRI/MRCP especially focal findings of chronic pancreatitis. Further studies needed to verify significance of these findings and establish MRI/MRCP imaging criteria for the diagnosis of chronic pancreatitis.

  4. TAT-MTS-MCM fusion proteins reduce MMA levels and improve mitochondrial activity and liver function in MCM-deficient cells.

    Science.gov (United States)

    Erlich-Hadad, Tal; Hadad, Rita; Feldman, Anat; Greif, Hagar; Lictenstein, Michal; Lorberboum-Galski, Haya

    2018-03-01

    Methylmalonic aciduria (MMA) is a disorder of organic acid metabolism resulting from a functional defect of the mitochondrial enzyme, methylmalonyl-CoA mutase (MCM). The main treatments for MMA patients are dietary restriction of propiogenic amino acids and carnitine supplementation. Liver or combined liver/kidney transplantation has been used to treat those with the most severe clinical manifestations. Thus, therapies are necessary to help improve quality of life and prevent liver, renal and neurological complications. Previously, we successfully used the TAT-MTS-Protein approach for replacing a number of mitochondrial-mutated proteins. In this targeted system, TAT, an 11 a.a peptide, which rapidly and efficiently can cross biological membranes, is fused to a mitochondrial targeting sequence (MTS), followed by the mitochondrial mature protein which sends the protein into the mitochondria. In the mitochondria, the TAT-MTS is cleaved off and the native protein integrates into its natural complexes and is fully functional. In this study, we used heterologous MTSs of human, nuclear-encoded mitochondrial proteins, to target the human MCM protein into the mitochondria. All fusion proteins reached the mitochondria and successfully underwent processing. Treatment of MMA patient fibroblasts with these fusion proteins restored mitochondrial activity such as ATP production, mitochondrial membrane potential and oxygen consumption, indicating the importance of mitochondrial function in this disease. Treatment with the fusion proteins enhanced cell viability and most importantly reduced MMA levels. Treatment also enhanced albumin and urea secretion in a CRISPR/Cas9-engineered HepG2 MUT (-/-) liver cell line. Therefore, we suggest using this TAT-MTS-Protein approach for the treatment of MMA. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  5. Kidney function and size in normal subjects before and during growth hormone administration for one week

    DEFF Research Database (Denmark)

    Gammelgaard, Jens; Orskov, H; Andersen, A R

    1981-01-01

    Kidney function and size were studied in seven normal male subjects before and after administration of highly purified human growth hormone for 1 week. Glomerular filtration rate, renal plasma flow (steady-state infusion technique with urinary collections using 125I-iothalamate and 131I-hippuran)......Kidney function and size were studied in seven normal male subjects before and after administration of highly purified human growth hormone for 1 week. Glomerular filtration rate, renal plasma flow (steady-state infusion technique with urinary collections using 125I-iothalamate and 131I...

  6. Trimethoprim-Sulfamethoxazole-Induced Hyperkalemia in a Patient with Normal Renal Function

    Directory of Open Access Journals (Sweden)

    L. Connor Nickels

    2012-01-01

    Full Text Available The authors present a case of Trimethoprim-sulfamethoxazole-induced hyperkalemia in a patient with normal renal function. While toxicity of this drug has been reported in patients with renal insufficiency, this case highlights the toxicity associated with normal kidney function. Due to its popularity in the medical field and to the largely unrecognized effect of hyperkalemia, it is important to consider such adverse effects when prescribing TMX-SMX. One must be reminded of the possibility of the development of life-threatening hyperkalemia in relatively healthy patients.

  7. Evaluation of mitochondrial respiratory function in highly glycolytic glioma cells reveals low ADP phosphorylation in relation to oxidative capacity.

    Science.gov (United States)

    Rodrigues-Silva, Erika; Siqueira-Santos, Edilene S; Ruas, Juliana S; Ignarro, Raffaela S; Figueira, Tiago R; Rogério, Fábio; Castilho, Roger F

    2017-07-01

    High-grade gliomas are aggressive and intensely glycolytic tumors. In the present study, we evaluated the mitochondrial respiratory function of glioma cells (T98G and U-87MG) and fresh human glioblastoma (GBM) tissue. To this end, measurements of oxygen consumption rate (OCR) were performed under various experimental conditions. The OCR of T98G and U-87MG cells was well coupled to ADP phosphorylation based on the ratio of ATP produced per oxygen consumed of ~2.5. In agreement, the basal OCR of GBM tissue was also partially associated with ADP phosphorylation. The basal respiration of intact T98G and U-87MG cells was not limited by the supply of endogenous substrates, as indicated by the increased OCR in response to a protonophore. These cells also displayed a high affinity for oxygen, as evidenced by the values of the partial pressure of oxygen when respiration is half maximal (p 50 ). In permeabilized glioma cells, ADP-stimulated OCR was only approximately 50% of that obtained in the presence of protonophore, revealing a significant limitation in oxidative phosphorylation (OXPHOS) relative to the activity of the electron transport system (ETS). This characteristic was maintained when the cells were grown under low glucose conditions. Flux control coefficient analyses demonstrated that the impaired OXPHOS was associated with the function of both mitochondrial ATP synthase and the adenine nucleotide translocator, but not the phosphate carrier. Altogether, these data indicate that the availability and metabolism of respiratory substrates and mitochondrial ETS are preserved in T98G and U-87MG glioma cells even though these cells possess a relatively restrained OXPHOS capability.

  8. Effects of acupuncture on declined cerebral blood flow, impaired mitochondrial respiratory function and oxidative stress in multi-infarct dementia rats.

    Science.gov (United States)

    Zhang, Xuezhu; Wu, Bangqi; Nie, Kun; Jia, Yujie; Yu, Jianchun

    2014-01-01

    Brain energy disorders and oxidative stress due to chronic hypoperfusion were considered to be the major risk factors in the pathogenesis of dementia. In previous studies, we have demonstrated that acupuncture treatment improved cognitive function of VaD patients and multi-infarct dementia (MID) rats. Acupuncture therapy also increased the activities of glycometabolic enzymes in the brain. But it is not clear whether acupuncture treatment compensates neuronal energy deficit after cerebral ischemic through enhancing the activities of glucose metabolic enzymes and preserving mitochondrial function, and whether acupuncture neuroprotective effect is associated with activations of mitochondrial antioxidative defense system. So, the effect of acupuncture therapy on cognitive function, cerebral blood flow (CBF), mitochondrial respiratory function and oxidative stress in the brain of MID rats was investigated in this study. The results showed that acupuncture treatment significantly improved cognitive abilities and increased regional CBF of MID rats. Acupuncture elevated the activities of total SOD, CuZnSOD and MnSOD, decreased the level of malondialdehyde (MDA) and superoxide anion, regulated the ratio of reduced glutathione (GSH) and oxidized glutathione (GSSG) in mitochondria, and raised the level of the respiratory control index (RCI) and P/O ratio and the activities of mitochondrial respiratory enzymes of MID rats. These results indicated that acupuncture treatment improved cognitive function of MID rats; and this improvement might be due to increased CBF, which ameliorated mitochondrial dysfunction induced by ischemia and endogenous oxidative stress system of brain. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Mitochondrial hepatopathies in the newborn period.

    Science.gov (United States)

    Fellman, Vineta; Kotarsky, Heike

    2011-08-01

    Mitochondrial disorders recognized in the neonatal period usually present as a metabolic crisis combined with one or several organ manifestations. Liver disorder in association with a respiratory chain deficiency may be overlooked since liver dysfunction is common in severely sick newborn infants. Lactacidosis, hypoglycemia, elevated serum transaminases and conjugated bilirubin are common signs of mitochondrial hepatopathy. Hepatosplenomegaly may occur in severe cases. A clinical picture with fetal growth restriction, postnatal lactacidosis, hypoglycemia, coagulopathy, and cholestasis, especially in combination with neurological symptoms or renal tubulopathy, should alert the neonatologist to direct investigations on mitochondrial disorder. A normal lactate level does not exclude respiratory chain defects. The most common liver manifestation caused by mutated mitochondrial DNA (deletion) is Pearson syndrome. Recently, mutations in several nuclear DNA genes have been identified that lead to mitochondrial hepatopathy, e.g. mitochondrial depletion syndrome caused by DGUOK, MPV17, SUCLG1, POLG1, or C10ORF2 mutations. A combination of lactacidosis, liver involvement, and Fanconi type renal tubulopathy is common when the complex III assembly factor BCS1L harbors mutations, the most severe disease with consistent genotype-phenotype correlation being the GRACILE syndrome. Mutations in nuclear translation factor genes (TRMU, EFG1, and EFTu) of the respiratory chain enzyme complexes have recently been identified. Diagnostic work-up of neonatal liver disorder should include assessment of function and structure of the complexes as well as mutation screening for known genes. So far, treatment is mainly symptomatic. Copyright © 2011. Published by Elsevier Ltd.

  10. Functional mutation of SMAC/DIABLO, encoding a mitochondrial proapoptotic protein, causes human progressive hearing loss DFNA64.

    Science.gov (United States)

    Cheng, Jing; Zhu, Yuhua; He, Sudan; Lu, Yanping; Chen, Jing; Han, Bing; Petrillo, Marco; Wrzeszczynski, Kazimierz O; Yang, Shiming; Dai, Pu; Zhai, Suoqiang; Han, Dongyi; Zhang, Michael Q; Li, Wei; Liu, Xuezhong; Li, Huawei; Chen, Zheng-Yi; Yuan, Huijun

    2011-07-15

    SMAC/DIABLO is a mitochondrial proapoptotic protein that is released from mitochondria during apoptosis and counters the inhibitory activities of inhibitor of apoptosis proteins, IAPs. By linkage analysis and candidate screening, we identified a heterozygous SMAC/DIABLO mutation, c.377C>T (p.Ser126Leu, refers to p.Ser71Leu in the mature protein) in a six-generation Chinese kindred characterized by dominant progressive nonsyndromic hearing loss, designated as DFNA64. SMAC/DIABLO is highly expressed in human embryonic ears and is enriched in the developing mouse inner-ear hair cells, suggesting it has a role in the development and homeostasis of hair cells. We used a functional study to demonstrate that the SMAC/DIABLO(S71L) mutant, while retaining the proapoptotic function, triggers significant degradation of both wild-type and mutant SMAC/DIABLO and renders host mitochondria susceptible to calcium-induced loss of the membrane potential. Our work identifies DFNA64 as the human genetic disorder associated with SMAC/DIABLO malfunction and suggests that mutant SMAC/DIABLO(S71L) might cause mitochondrial dysfunction. Copyright © 2011 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  11. Functional coexpression of the mitochondrial alternative oxidase and uncoupling protein underlies thermoregulation in the thermogenic florets of skunk cabbage.

    Science.gov (United States)

    Onda, Yoshihiko; Kato, Yoshiaki; Abe, Yukie; Ito, Takanori; Morohashi, Miyuki; Ito, Yuka; Ichikawa, Megumi; Matsukawa, Kazushige; Kakizaki, Yusuke; Koiwa, Hiroyuki; Ito, Kikukatsu

    2008-02-01

    Two distinct mitochondrial energy dissipating systems, alternative oxidase (AOX) and uncoupling protein (UCP), have been implicated as crucial components of thermogenesis in plants and animals, respectively. To further clarify the physiological roles of AOX and UCP during homeothermic heat production in the thermogenic skunk cabbage (Symplocarpus renifolius), we identified the thermogenic cells and performed expression and functional analyses of these genes in this organism. Thermographic analysis combined with in situ hybridization revealed that the putative thermogenic cells surround the stamens in the florets of skunk cabbage and coexpress transcripts for SrAOX, encoding Symplocarpus AOX, and SrUCPb, encoding a novel UCP that lacks a fifth transmembrane segment. Mitochondria isolated from the thermogenic florets exhibited substantial linoleic acid (LA)-inducible uncoupling activities. Moreover, our results demonstrate that LA is capable of inhibiting the mitochondrial AOX pathway, whereas the proportion of pyruvate-stimulated AOX capacity was not significantly affected by LA. Intriguingly, the protein expression levels for SrAOX and SrUCPb were unaffected even when the ambient air temperatures increased from 10.3 degrees C to 23.1 degrees C or from 8.3 degrees C to 24.9 degrees C. Thus, our results suggest that functional coexpression of AOX and UCP underlies the molecular basis of heat production, and that posttranslational modifications of these proteins play a crucial role in regulating homeothermic heat production under conditions of natural ambient temperature fluctuations in skunk cabbage.

  12. Anaplerotic Triheptanoin Diet Enhances Mitochondrial Substrate Use to Remodel the Metabolome and Improve Lifespan, Motor Function, and Sociability in MeCP2-Null Mice

    Science.gov (United States)

    Li, Qun; Degano, Alicia L.; Penati, Judith; Zhuo, Justin; Roe, Charles R.; Ronnett, Gabriele V.

    2014-01-01

    Rett syndrome (RTT) is an autism spectrum disorder (ASD) caused by mutations in the X-linked MECP2 gene that encodes methyl-CpG binding protein 2 (MeCP2). Symptoms range in severity and include psychomotor disabilities, seizures, ataxia, and intellectual disability. Symptom onset is between 6-18 months of age, a critical period of brain development that is highly energy-dependent. Notably, patients with RTT have evidence of mitochondrial dysfunction, as well as abnormal levels of the adipokines leptin and adiponectin, suggesting overall metabolic imbalance. We hypothesized that one contributor to RTT symptoms is energy deficiency due to defective nutrient substrate utilization by the TCA cycle. This energy deficit would lead to a metabolic imbalance, but would be treatable by providing anaplerotic substrates to the TCA cycle to enhance energy production. We show that dietary therapy with triheptanoin significantly increased longevity and improved motor function and social interaction in male mice hemizygous for Mecp2 knockout. Anaplerotic therapy in Mecp2 knockout mice also improved indicators of impaired substrate utilization, decreased adiposity, increased glucose tolerance and insulin sensitivity, decreased serum leptin and insulin, and improved mitochondrial morphology in skeletal muscle. Untargeted metabolomics of liver and skeletal muscle revealed increases in levels of TCA cycle intermediates with triheptanoin diet, as well as normalizations of glucose and fatty acid biochemical pathways consistent with the improved metabolic phenotype in Mecp2 knockout mice on triheptanoin. These results suggest that an approach using dietary supplementation with anaplerotic substrate is effective in improving symptoms and metabolic health in RTT. PMID:25299635

  13. Respiratory functions in asthmatic and normal women during different phases of menstrual cycle

    International Nuclear Information System (INIS)

    Arora, D.B.; Sandhu, P.K.; Dhillon, S.; Arora, A.

    2015-01-01

    Menstrual cycle is an integral part of life of women. There is widespread agreement that changes in the levels of oestrogen and progesterone associated with menstrual cycle also affect different systems of the body besides reproductive system. Levels of oestrogen and progesterone are maximum in the secretory phase and minimum just before the menstruation .Bronchial asthma is one of the commonest chronic respiratory diseases. Premenstrual worsening of asthma symptoms has been reported to affect 33-40% of asthmatic women. This exacerbation of asthma symptoms has been correlated with the oestrogen and progesterone levels. The association between menstrual cycle and lung functions in normal females has also been recognised. The pathophysiology of this process is still not proved. The purpose of our study was to confirm the probable effects of the female hormones on lung functions in normal and asthmatic women in different phases of menstrual cycle and to compare them. Methods: The study was done on 40 normal and 40 asthmatic females in the age group of 15-45 years. Pulmonary function tests were done in three phases of menstrual cycle i.e. follicular, secretory and menstrual in all the subjects. Results: The mean value of lung functions, i.e., FVC, FEV, PEFR, FEF25-75%, FEF 200-1200 were significantly lower in asthmatic females than normal ones (p<0.01) in all three phases. The lung functions of both asthmatic and non-asthmatic females in secretory phase were significantly higher than in menstrual phase (p<0.005). The PFTs in menstrual phase were even lower than the follicular phase (p<0.04). Conclusion: Respiratory parameters of both asthmatic and non-asthmatic women in reproductive age group show significant variation in different phases of menstrual cycle. The smooth muscle relaxant effect of progesterone and probably oestrogen might have contributed to it. The lung function parameters in asthmatics were of lower value compared to normal women. (author)

  14. Consistency rates and asymptotic normality of the high risk conditional for functional data

    Directory of Open Access Journals (Sweden)

    Rabhi Abbes

    2015-12-01

    Full Text Available The maximum of the conditional hazard function is a parameter of great importance in seismicity studies, because it constitutes the maximum risk of occurrence of an earthquake in a given interval of time. Using the kernel nonparametric estimates of the first derivative of the conditional hazard function, we establish uniform convergence properties and asymptotic normality of an estimate of the maximum in the context of independence data.

  15. Consistency rates and asymptotic normality of the high risk conditional for functional data

    Directory of Open Access Journals (Sweden)

    Rabhi Abbes

    2016-08-01

    Full Text Available The maximum of the conditional hazard function is a parameter of great importance in seismicity studies, because it constitutes the maximum risk of occurrence of an earthquake in a given interval of time. Using the kernel nonparametric estimates of the first derivative of the conditional hazard function, we establish uniform convergence properties and asymptotic normality of an estimate of the maximum in the context of independence data.

  16. Estradiol and tamoxifen regulate NRF-1 and mitochondrial function in mouse mammary gland and uterus

    Science.gov (United States)

    Ivanova, Margarita M.; Radde, Brandie N.; Son, Jieun; Mehta, Fabiola F.; Chung, Sang-Hyuk; Klinge, Carolyn M.

    2013-01-01

    Nuclear respiratory factor-1 (NRF-1) stimulates the transcription of nuclear-encoded genes that regulate mitochondrial genome transcription and biogenesis. We reported that estradiol (E2) and 4-hydroxytamoxifen (4-OHT) stimulate NRF-1 transcription in an estrogen receptor α- and β- (ERα, ERβ) dependent manner in human breast cancer cells. The aim of this study was to determine if E2 and 4-OHT increase NRF-1 in vivo. Here we report that E2 and 4-OHT increase NRF-1 expression in mammary gland and uterus of ovariectomized C57BL/6 mice in a time-dependent manner. E2 increased NRF-1 protein in the uterus and mammary gland; however, in mammary gland, 4-OHT increased Nrf1 mRNA but not protein. Chromatin immunoprecipitation (ChIP) assays revealed increased in vivo recruitment of ERα to the Nrf1 promoter and intron 3 in mammary gland and uterus 6 h after E2 and 4-OHT treatment, commensurate with increased NRF-1 expression. E2 and 4-OHT- induced increases in NRF-1 and its target genes Tfam, Tfb1m, and Tfb2m were coordinated in mammary gland but not uterus, due to uterine-selective inhibition of the expression of the NRF-1 coactivators Ppargc1a and Ppargc1b by E2 and 4-OHT. E2 transiently increased NRF-1 and PGC-1α nuclear staining while reducing PGC-1α in uterus. E2, not 4-OHT, activates mitochondrial biogenesis in mammary gland and uterus in a time-dependent manner. E2 increased mitochondrial outer membrane Tom40 protein levels in mammary gland and uterus whereas 4-OHT increased Tom40 only in uterus. These data support the hypothesis of tissue-selective regulation of NRF-1 and its downstream targets by E2 and 4-OHT in vivo. PMID:23892277

  17. Disturbed mitochondrial function restricts glutamate uptake in the human Müller glia cell line, MIO-M1

    DEFF Research Database (Denmark)

    Vohra, Rupali; Gurubaran, Iswariyaraja Sridevi; Henriksen, Ulrik

    2017-01-01

    and glucose restriction. Lactate release decreased in response to glucose restriction. Combined glucose restriction and blocked mitochondrial activity decreased survival and caused collapse of the respiratory chain measured by oxygen consumption rate and extracellular acidification rate. Mitochondrial...

  18. Maintaining ancient organelles: mitochondrial biogenesis and maturation.

    Science.gov (United States)

    Vega, Rick B; Horton, Julie L; Kelly, Daniel P

    2015-05-22

    The ultrastructure of the cardiac myocyte is remarkable for the high density of mitochondria tightly packed between sarcomeres. This structural organization is designed to provide energy in the form of ATP to fuel normal pump function of the heart. A complex system comprised of regulatory factors and energy metabolic machinery, encoded by both mitochondrial and nuclear genomes, is required for the coordinate control of cardiac mitochondrial biogenesis, maturation, and high-capacity function. This process involves the action of a transcriptional regulatory network that builds and maintains the mitochondrial genome and drives the expression of the energy transduction machinery. This finely tuned system is responsive to developmental and physiological cues, as well as changes in fuel substrate availability. Deficiency of components critical for mitochondrial energy production frequently manifests as a cardiomyopathic phenotype, underscoring the requirement to maintain high respiration rates in the heart. Although a precise causative role is not clear, there is increasing evidence that perturbations in this regulatory system occur in the hypertrophied and failing heart. This review summarizes current knowledge and highlights recent advances in our understanding of the transcriptional regulatory factors and signaling networks that serve to regulate mitochondrial biogenesis and function in the mammalian heart. © 2015 American Heart Association, Inc.

  19. Structure and function of the native and recombinant mitochondrial MRP1/MRP2 complex from

    Czech Academy of Sciences Publication Activity Database

    Zíková, Alena; Kopečná, Jana; Schumacher, M. A.; Stuart, K.; Trantírek, Lukáš; Lukeš, Julius

    2008-01-01

    Roč. 38, 8/9 (2008), s. 901-912 ISSN 0020-7519 R&D Projects: GA MŠk 2B06129; GA ČR GA204/06/1558; GA AV ČR IAA500960705; GA ČR GP204/04/P191; GA MŠk LC07032; GA MŠk(CZ) 1K04011 Institutional research plan: CEZ:AV0Z60220518 Keywords : frataxin * mitochondrie * trypanosoma * rozsivka * evoluční konzervovanost * import Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.752, year: 2008

  20. Connection between Dynamically Derived Initial Mass Function Normalization and Stellar Population Parameters

    NARCIS (Netherlands)

    McDermid, Richard M.; Cappellari, Michele; Alatalo, Katherine; Bayet, Estelle; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, Martin; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

    We report on empirical trends between the dynamically determined stellar initial mass function (IMF) and stellar population properties for a complete, volume-limited sample of 260 early-type galaxies from the ATLAS3D project. We study trends between our dynamically derived IMF normalization αdyn ≡

  1. Low-normal thyroid function and the pathogenesis of common cardio-metabolic disorders

    NARCIS (Netherlands)

    van Tienhoven-Wind, Lynnda J. N.; Dullaart, Robin P. F.

    BackgroundSubclinical hypothyroidism may adversely affect the development of cardiovascular disease (CVD). Less is known about the role of low-normal thyroid function, that is higher thyroid-stimulating hormone and/or lower free thyroxine levels within the euthyroid reference range, in the

  2. Convergence Theorems for Generalized Functional Sequences of Discrete-Time Normal Martingales

    Directory of Open Access Journals (Sweden)

    Caishi Wang

    2015-01-01

    of generalized functional sequences of a discrete-time normal martingale M. A necessary and sufficient condition in terms of the Fock transform is obtained for such a sequence to be strongly convergent. A type of generalized martingales associated with M is introduced and their convergence theorems are established. Some applications are also shown.

  3. A study of the up-and-down method for non-normal distribution functions

    DEFF Research Database (Denmark)

    Vibholm, Svend; Thyregod, Poul

    1988-01-01

    The assessment of breakdown probabilities is examined by the up-and-down method. The exact maximum-likelihood estimates for a number of response patterns are calculated for three different distribution functions and are compared with the estimates corresponding to the normal distribution. Estimates...

  4. ACS6, a Hydrogen sulfide-donating derivative of sildenafil, inhibits homocysteine-induced apoptosis by preservation of mitochondrial function

    Directory of Open Access Journals (Sweden)

    Tang Xiao-Qing

    2011-08-01

    Full Text Available Abstract Background The hydrogen sulfide-releasing sildenafil, ACS6, has been demonstrated to inhibit superoxide formation through donating hydrogen sulfide (H2S. We have found that H2S antagonizes homocysteine-induced oxidative stress and neurotoxicity. The aim of the present study is to explore the protection of ACS6 against homocysteine-triggered cytotoxicity and apoptosis and the molecular mechanisms underlying in PC12 cells. Methods Cell viability was determined by Cell Counting Kit-8 assay. Cell apoptosis was observed using the chromatin dye Hoechst 33258 and analyzed by Flow Cytometry after propidium iodide staining. Mitochondrial membrane potential was monitored using the fluorescent dye Rh123. Intracellular reactive oxygen species were determined by oxidative conversion of cell permeable 2',7'-dichlorfluorescein-diacetate to fluorescent 2',7'-dichlorfluorescein. The expression of cleaved caspase-3 and bcl-2 and the accumulation of cytosolic cytochrome c were analyzed by Western blot. Results We show that ACS6 protects PC12 cells against cytotoxicity and apoptosis induced by homocysteine and blocks homocysteine-triggered cytochrome c release and caspase-3 activation. ACS6 treatment results in not only prevention of homocysteine-caused mitochondrial membrane potential (Δψ loss and reactive oxygen species (ROS overproduction but also reversal of Bcl-2 down-expression. Conclusions These results indicate that ACS6 protects PC12 cells against homocysteine-induced cytotoxicity and apoptosis by preservation of mitochondrial function though inhibiting both loss of Δψ and accumulation of ROS as well as modulating the expression of Bcl-2. Our study provides evidence both for a neuroprotective effect of ACS6 and for further evaluation of ACS6 as novel neuroprotectants for Alzheimer's disease associated with homocysteine.

  5. A phylogenetic analysis of normal modes evolution in enzymes and its relationship to enzyme function.

    Science.gov (United States)

    Lai, Jason; Jin, Jing; Kubelka, Jan; Liberles, David A

    2012-09-21

    Since the dynamic nature of protein structures is essential for enzymatic function, it is expected that functional evolution can be inferred from the changes in protein dynamics. However, dynamics can also diverge neutrally with sequence substitution between enzymes without changes of function. In this study, a phylogenetic approach is implemented to explore the relationship between enzyme dynamics and function through evolutionary history. Protein dynamics are described by normal mode analysis based on a simplified harmonic potential force field applied to the reduced C(α) representation of the protein structure while enzymatic function is described by Enzyme Commission numbers. Similarity of the binding pocket dynamics at each branch of the protein family's phylogeny was analyzed in two ways: (1) explicitly by quantifying the normal mode overlap calculated for the reconstructed ancestral proteins at each end and (2) implicitly using a diffusion model to obtain the reconstructed lineage-specific changes in the normal modes. Both explicit and implicit ancestral reconstruction identified generally faster rates of change in dynamics compared with the expected change from neutral evolution at the branches of potential functional divergences for the α-amylase, D-isomer-specific 2-hydroxyacid dehydrogenase, and copper-containing amine oxidase protein families. Normal mode analysis added additional information over just comparing the RMSD of static structures. However, the branch-specific changes were not statistically significant compared to background function-independent neutral rates of change of dynamic properties and blind application of the analysis would not enable prediction of changes in enzyme specificity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Melatonin antiproliferative effects require active mitochondrial function in embryonal carcinoma cells

    Science.gov (United States)

    Loureiro, Rute; Magalhães-Novais, Silvia; Mesquita, Katia A.; Baldeiras, Ines; Sousa, Isabel S.; Tavares, Ludgero C.; Barbosa, Ines A.; Oliveira, Paulo J.; Vega-Naredo, Ignacio

    2015-01-01

    Although melatonin oncostatic and cytotoxic effects have been described in different types of cancer cells, the specific mechanisms leading to its antitumoral effects and their metabolic context specificity are still not completely understood. Here, we evaluated the effects of melatonin in P19 embryonal carcinoma stem cells (CSCs) and in their differentiated counterparts, cultured in either high glucose medium or in a galactose (glucose-free) medium which leads to glycolytic suppression and increased mitochondrial metabolism. We found that highly glycolytic P19 CSCs were less susceptible to melatonin antitumoral effects while cell populations relying on oxidative metabolism for ATP production were more affected. The observed antiproliferative action of melatonin was associated with an arrest at S-phase, decreased oxygen consumption, down-regulation of BCL-2 expression and an increase in oxidative stress culminating with caspase-3-independent cell death. Interestingly, the combined treatment of melatonin and dichloroacetate had a synergistic effect in cells grown in the galactose medium and resulted in an inhibitory effect in the highly resistant P19 CSCs. Melatonin appears to exert its antiproliferative activity in P19 carcinoma cells through a mitochondrially-mediated action which in turn allows the amplification of the effects of dichloroacetate, even in cells with a more glycolytic phenotype. PMID:26025920

  7. Diabetic Polyneuropathy in Type 2 Diabetes Mellitus: Inflammation, Oxidative Stress, and Mitochondrial Function

    Directory of Open Access Journals (Sweden)

    Luis Miguel Román-Pintos

    2016-01-01

    Full Text Available Diabetic polyneuropathy (DPN is defined as peripheral nerve dysfunction. There are three main alterations involved in the pathologic changes of DPN: inflammation, oxidative stress, and mitochondrial dysfunction. Inflammation induces activation of nuclear factor kappa B, activator protein 1, and mitogen-activated protein kinases. Oxidative stress induced by hyperglycemia is mediated by several identified pathways: polyol, hexosamine, protein kinase C, advanced glycosylation end-products, and glycolysis. In addition, mitochondrial dysfunction accounts for most of the production of reactive oxygen and nitrosative species. These free radicals cause lipid peroxidation, protein modification, and nucleic acid damage, to finally induce axonal degeneration and segmental demyelination. The prevalence of DPN ranges from 2.4% to 78.8% worldwide, depending on the diagnostic method and the population assessed (hospital-based or outpatients. Risk factors include age, male gender, duration of diabetes, uncontrolled glycaemia, height, overweight and obesity, and insulin treatment. Several diagnostic methods have been developed, and composite scores combined with nerve conduction studies are the most reliable to identify early DPN. Treatment should be directed to improve etiologic factors besides reducing symptoms; several approaches have been evaluated to reduce neuropathic impairments and improve nerve conduction, such as oral antidiabetics, statins, and antioxidants (alpha-lipoic acid, ubiquinone, and flavonoids.

  8. Biotin deprivation impairs mitochondrial structure and function and has implications for inherited metabolic disorders.

    Science.gov (United States)

    Ochoa-Ruiz, Estefanía; Díaz-Ruiz, Rodrigo; Hernández-Vázquez, Alaín de J; Ibarra-González, Isabel; Ortiz-Plata, Alma; Rembao, Daniel; Ortega-Cuéllar, Daniel; Viollet, Benoit; Uribe-Carvajal, Salvador; Corella, José Ahmed; Velázquez-Arellano, Antonio

    2015-11-01

    Certain inborn errors of metabolism result from deficiencies in biotin containing enzymes. These disorders are mimicked by dietary absence or insufficiency of biotin, ATP deficit being a major effect,whose responsible mechanisms have not been thoroughly studied. Here we show that in rats and cultured cells it is the result of reduced TCA cycle flow, partly due to deficient anaplerotic biotin-dependent pyruvate carboxylase. This is accompanied by diminished flow through the electron transport chain, augmented by deficient cytochrome c oxidase (complex IV) activity with decreased cytochromes and reduced oxidative phosphorylation. There was also severe mitochondrial damage accompanied by decrease of mitochondria, associated with toxic levels of propionyl CoA as shown by carnitine supplementation studies, which explains the apparently paradoxical mitochondrial diminution in the face of the energy sensor AMPK activation, known to induce mitochondria biogenesis. This idea was supported by experiments on AMPK knockout mouse embryonic fibroblasts (MEFs). The multifactorial ATP deficit also provides a plausible basis for the cardiomyopathy in patients with propionic acidemia, and other diseases.Additionally, systemic inflammation concomitant to the toxic state might explain our findings of enhanced IL-6, STAT3 and HIF-1α, associated with an increase of mitophagic BNIP3 and PINK proteins, which may further increase mitophagy. Together our results imply core mechanisms of energy deficit in several inherited metabolic disorders.

  9. Diabetic Polyneuropathy in Type 2 Diabetes Mellitus: Inflammation, Oxidative Stress, and Mitochondrial Function.

    Science.gov (United States)

    Román-Pintos, Luis Miguel; Villegas-Rivera, Geannyne; Rodríguez-Carrizalez, Adolfo Daniel; Miranda-Díaz, Alejandra Guillermina; Cardona-Muñoz, Ernesto Germán

    2016-01-01

    Diabetic polyneuropathy (DPN) is defined as peripheral nerve dysfunction. There are three main alterations involved in the pathologic changes of DPN: inflammation, oxidative stress, and mitochondrial dysfunction. Inflammation induces activation of nuclear factor kappa B, activator protein 1, and mitogen-activated protein kinases. Oxidative stress induced by hyperglycemia is mediated by several identified pathways: polyol, hexosamine, protein kinase C, advanced glycosylation end-products, and glycolysis. In addition, mitochondrial dysfunction accounts for most of the production of reactive oxygen and nitrosative species. These free radicals cause lipid peroxidation, protein modification, and nucleic acid damage, to finally induce axonal degeneration and segmental demyelination. The prevalence of DPN ranges from 2.4% to 78.8% worldwide, depending on the diagnostic method and the population assessed (hospital-based or outpatients). Risk factors include age, male gender, duration of diabetes, uncontrolled glycaemia, height, overweight and obesity, and insulin treatment. Several diagnostic methods have been developed, and composite scores combined with nerve conduction studies are the most reliable to identify early DPN. Treatment should be directed to improve etiologic factors besides reducing symptoms; several approaches have been evaluated to reduce neuropathic impairments and improve nerve conduction, such as oral antidiabetics, statins, and antioxidants (alpha-lipoic acid, ubiquinone, and flavonoids).

  10. Po2 cycling protects diaphragm function during reoxygenation via ROS, Akt, ERK, and mitochondrial channels.

    Science.gov (United States)

    Zuo, Li; Pannell, Benjamin K; Re, Anthony T; Best, Thomas M; Wagner, Peter D

    2015-12-01

    Po2 cycling, often referred to as intermittent hypoxia, involves exposing tissues to brief cycles of low oxygen environments immediately followed by hyperoxic conditions. After experiencing long-term hypoxia, muscle can be damaged during the subsequent reintroduction of oxygen, which leads to muscle dysfunction via reperfusion injury. The protective effect and mechanism behind Po2 cycling in skeletal muscle during reoxygenation have yet to be fully elucidated. We hypothesize that Po2 cycling effectively increases muscle fatigue resistance through reactive oxygen species (ROS), protein kinase B (Akt), extracellular signal-regulated kinase (ERK), and certain mitochondrial channels during reoxygenation. Using a dihydrofluorescein fluorescent probe, we detected the production of ROS in mouse diaphragmatic skeletal muscle in real time under confocal microscopy. Muscles treated with Po2 cycling displayed significantly attenuated ROS levels (n = 5; P Po2 cycling treatment. This current investigation has discovered a correlation between KATP and mPTP and the Po2 cycling pathway in diaphragmatic skeletal muscle. Thus we have identified a unique signaling pathway that may involve ROS, Akt, ERK, and mitochondrial channels responsible for Po2 cycling protection during reoxygenation conditions in the diaphragm. Copyright © 2015 the American Physiological Society.

  11. Protean manifestations of mitochondrial diseases: a minireview.

    Science.gov (United States)

    Kerr, D S

    1997-01-01

    Mitochondrial abnormalities are major causes of human disease. Pearson syndrome illustrates many features of abnormal mitochondrial function and genetics. Mitochondria from adenosine triphosphate (ATP) via five multienzyme complexes of the electron transport chain and oxidative phosphorylation, composed from a blend of nuclear and mitochondrial gene products. Mitochondrial DNA (mtDNA) is small (16.6 kb), encoding some subunits of these complexes as well as transfer RNA (tRNA) and ribosomal RNA, but is replicated and transcribed by nuclear encoded polymerases. Multiple copies of mtDNA are passed on to progeny cells via the cytoplasm, accounting for maternal inheritance. Normal and mutant mtDNA can coexist within the same cell (heteroplasmy); when the proportion of mutant mtDNA exceeds a threshold, cellular function is impaired, resulting in disease. MtDNA abnormalities include point mutations, deletions, and depletion. Point mutations in an enzyme subunit cause a specific disorder, whereas point mutations in the tRNAs result in general impairment of protein synthesis and are associated with a variety of disorders. Large mtDNA deletions, initially described in Kearns-Sayre syndrome (KSS), were found soon thereafter in Pearson syndrome. Survivors of Pearson syndrome have gone on to develop KSS. A whole spectrum of disease forms, ranging from isolated sideroblastic anemia to combined Pearson and KSS, are associated with deletions of mtDNA. Diagnosis of mitochondrial disorders depends on clinical suspicion, enhanced by evidence of abnormal mitochondrial structure, number, and/or function. Effective treatment for mitochondrial disorders is very limited, including correction of the metabolic milieu, activation of enzyme activity by drugs or cofactors, and removal of reactive oxygen species.

  12. The Alterations in Mitochondrial DNA Copy Number and Nuclear-Encoded Mitochondrial Genes in Rat Brain Structures after Cocaine Self-Administration.

    Science.gov (United States)

    Sadakierska-Chudy, Anna; Kotarska, Agnieszka; Frankowska, Małgorzata; Jastrzębska, Joanna; Wydra, Karolina; Miszkiel, Joanna; Przegaliński, Edmund; Filip, Małgorzata

    2017-11-01

    The repeated intake of cocaine evokes oxidative stress that is present even during drug withdrawal. Recent studies demonstrate that cocaine-induced oxidative and/or endoplasmic reticulum stress can affect mitochondrial function and dynamics as well as the expression of mitochondrial and nuclear genes. These alterations in mitochondrial function may determine synaptic and behavioral plasticity. Mitochondria and mitochondrial DNA (mtDNA) seem to play an important role in the initiation of drug addiction. We used a microarray approach to investigate the expression patterns of nuclear-encoded genes relevant for mitochondrial functions and quantitative real-time PCR assays to determine the numbers of copies of mtDNA and of mRNAs corresponding to two mitochondrial proteins in the prefrontal cortex and hippocampus of rats during early cocaine abstinence. We found a significant elevation in the copy number of mtDNA and concomitant increased expression of mitochondrial genes. Moreover, microarray analysis revealed changes in the transcription of nuclear genes engaged in mtDNA replication, nucleoid formation, the oxidative phosphorylation pathway, and mitochondrial fission and fusion. Finally, we observed the upregulation of endoplasmic reticulum stress-induced genes. Cocaine self-administration influences the expression of both nuclear and mitochondrial genes as well as mtDNA replication. To determine whether these alterations serve as compensatory mechanisms to help maintain normal level of ATP production, further studies are necessary.

  13. Two potential Petunia hybrida mitochondrial DNA replication origins show structural and in vitro functional homology with the animal mitochondrial DNA heavy and light strand replication origins

    NARCIS (Netherlands)

    Haas, Jan M. de; Hille, Jacques; Kors, Frank; Meer, Bert van der; Kool, Ad J.; Folkerts, Otto; Nijkamp, H. John J.

    1991-01-01

    Four Petunia hybrida mitochondrial (mt) DNA fragments have been isolated, sequenced, localized on the physical map and analyzed for their ability to initiate specific DNA synthesis. When all four mtDNA fragments were tested as templates in an in vitro DNA synthesizing lysate system, developed from

  14. Normal Bowel Pattern in Children and Dietary and Other Precipitating Factors in Functional Constipation.

    Science.gov (United States)

    Sujatha, Balamma; Velayutham, Dhakshyani Raghavan; Deivamani, Nirmala; Bavanandam, Sumathi

    2015-06-01

    To study the bowel pattern of children in general population and children with habit constipation with respect to food habits and regarding psychosocial aspect of toileting. A prospective descriptive study was done in the Institute of child health and hospital for children, Chennai, with two groups, Functional constipation group and Normal bowel pattern group. The functional group included the children with the age group of 2-12 years, of either sex who fulfilled the ROME III criteria for constipation. Normal bowel pattern group had school children of age group 6-12 years of age and 2-5-year-old children attending OPD for minor ailments. The demographic profile, socioeconomic status, complaints, psychosocial aspects affecting bowel pattern and diet chart were collected and recorded from the parents in proforma. Stool frequency and type of stool passed were recorded for a week, with Bristol stool chart. A total of 523 and 131 children were analysed for normal bowel pattern and functional constipation respectively. Data analysis done using SPSS version 15. The prevalence of functional constipation was noted in 13.5% with female preponderance and in the age group of 2-4 years. Constipation continues to be a problem, mostly under recognised in older population. Psychosocial factors had a significant effect on functional constipation. Skipping breakfast, early toilet training, low intake of vegetables and fruits were other factors of significance leading to constipation.

  15. The effects on the pulmonary function of normal adults proprioceptive neuromuscular facilitation respiration pattern exercise.

    Science.gov (United States)

    Seo, KyoChul; Cho, MiSuk

    2014-10-01

    [Purpose] The purpose of this study was to determine whether proprioceptive neuromuscular facilitation (PNF) respiration exercise increases the pulmonary function of normal adults. [Subjects and Methods] Twenty-eight normal adults in their 20s were randomly assigned to an experimental group (n=14) or control group (n=14). Over the course of four weeks, the experimental group participated in PNF respiration pattern exercises for 30 minutes three times per week. Subjects were assessed pre-test and post-test by measurement of pulmonary function (tidal volume, inspiratory reserve volume, expiratory reserve volume, inspiratory capacity, and vital capacity). [Results] Our findings show that the experimental group had significant improvements in expiratory reserve volume and vital capacity. In the comparison of the two groups, the experimental group had higher pulmonary function than the control group. [Conclusion] In this study, the experimental group showed greater improvement in pulmonary function than the control group, which indicates that the PNF respiration exercise is effective at increasing the pulmonary function of normal adults.

  16. Normal Bowel Pattern in Children and Dietary and Other Precipitating Factors in Functional Constipation

    Science.gov (United States)

    Velayutham, Dhakshyani Raghavan; Deivamani, Nirmala; Bavanandam, Sumathi

    2015-01-01

    Aim To study the bowel pattern of children in general population and children with habit constipation with respect to food habits and regarding psychosocial aspect of toileting. Materials and Methods A prospective descriptive study was done in the Institute of child health and hospital for children, Chennai, with two groups, Functional constipation group and Normal bowel pattern group. The functional group included the children with the age group of 2-12 years, of either sex who fulfilled the ROME III criteria for constipation. Normal bowel pattern group had school children of age group 6-12 years of age and 2-5-year-old children attending OPD for minor ailments. The demographic profile, socioeconomic status, complaints, psychosocial aspects affecting bowel pattern and diet chart were collected and recorded from the parents in proforma. Stool frequency and type of stool passed were recorded for a week, with Bristol stool chart. Results A total of 523 and 131 children were analysed for normal bowel pattern and functional constipation respectively. Data analysis done using SPSS version 15. The prevalence of functional constipation was noted in 13.5% with female preponderance and in the age group of 2-4 years. Conclusion Constipation continues to be a problem, mostly under recognised in older population. Psychosocial factors had a significant effect on functional constipation. Skipping breakfast, early toilet training, low intake of vegetables and fruits were other factors of significance leading to constipation. PMID:26266179

  17. Effects of compliance monitoring of vocal function exercises on voice outcome measures for normal voice.

    Science.gov (United States)

    Ellis, Lee W; Beltyukova, Svetlana A

    2011-06-01

    This experimental study examined the efficacy of the vocal function exercise program in improving voice production in individuals with normal voices. 20 young women (M age = 22 yr.) with normal voices, 10 in the Monitored compliance group and 10 in the Unmonitored compliance group, received training in performing vocal function exercises followed by daily practice of the exercises for 28 consecutive days. Participants in the Monitored compliance group were required to submit audio or video recordings of their daily practice of vocal function exercises, and those in the Unmonitored compliance group were not required to record their daily practice sessions. Results indicated that while the participants in both groups significantly increased maximum phonation times and maximum phonational frequency ranges, those in the Monitored group improved significantly more than the participants in the Unmonitored group on these outcome measures.

  18. Green tea polyphenols stimulate mitochondrial biogenesis and improve renal function after chronic cyclosporin a treatment in rats.

    Directory of Open Access Journals (Sweden)

    Hasibur Rehman

    Full Text Available Our previous studies showed that an extract from Camellia sinenesis (green tea, which contains several polyphenols, attenuates nephrotoxicity caused by cyclosporine A (CsA. Since polyphenols are stimulators of mitochondrial biogenesis (MB, this study investigated whether stimulation of MB plays a role in green tea polyphenol protection against CsA renal toxicity. Rats were fed a powdered diet containing green tea polyphenolic extract (0.1% starting 3 days prior to CsA treatment (25 mg/kg, i.g. daily for 3 weeks. CsA alone decreased renal nuclear DNA-encoded oxidative phosphorylation (OXPHOS protein ATP synthase-β (AS-β by 42%, mitochondrial DNA (mtDNA-encoded OXPHOS protein NADH dehydrogenase-3 (ND3 by 87% and their associated mRNAs. Mitochondrial DNA copy number was also decreased by 78% by CsA. Immunohistochemical analysis showed decreased cytochrome c oxidase subunit IV (COX-IV, an OXPHOS protein, in tubular cells. Peroxisome proliferator-activated receptor-γ coactivator (PGC-1α, the master regulator of MB, and mitochondrial transcription factor-A (Tfam, the transcription factor that regulates mtDNA replication and transcription, were 42% and 90% lower, respectively, in the kidneys of CsA-treated than in untreated rats. These results indicate suppression of MB by chronic CsA treatment. Green tea polyphenols alone and following CsA increased AS-β, ND3, COX-IV, mtDNA copy number, PGC-1α mRNA and protein, decreased acetylated PGC-1α, and increased Tfam mRNA and protein. In association with suppressed MB, CsA increased serum creatinine, caused loss of brush border and dilatation of proximal tubules, tubular atrophy, vacuolization, apoptosis, calcification, and increased neutrophil gelatinase-associated lipocalin expression, leukocyte infiltration, and renal fibrosis. Green tea polyphenols markedly attenuated CsA-induced renal injury and improved renal function. Together, these results demonstrate that green tea polyphenols attenuate Cs

  19. Inhibitors of Succinate: Quinone Reductase/Complex II Regulate Production of Mitochondrial Reactive Oxygen Species and Protect Normal Cells from Ischemic Damage but Induce Specific Cancer Cell Death

    Czech Academy of Sciences Publication Activity Database

    Ralph, S.J.; Moreno-Sanchez, R.; Neužil, Jiří; Rodriguez-Enriquez, S.

    2011-01-01

    Roč. 28, č. 11 (2011), s. 2695-2730 ISSN 0724-8741 Institutional research plan: CEZ:AV0Z50520701 Keywords : Mitocans * SDH/Complex II * mitochondrial ROS production Subject RIV: CE - Biochemistry Impact factor: 4.093, year: 2011

  20. Pore size determination using normalized J-function for different hydraulic flow units

    Directory of Open Access Journals (Sweden)

    Ali Abedini

    2015-06-01

    Full Text Available Pore size determination of hydrocarbon reservoirs is one of the main challenging areas in reservoir studies. Precise estimation of this parameter leads to enhance the reservoir simulation, process evaluation, and further forecasting of reservoir behavior. Hence, it is of great importance to estimate the pore size of reservoir rocks with an appropriate accuracy. In the present study, a modified J-function was developed and applied to determine the pore radius in one of the hydrocarbon reservoir rocks located in the Middle East. The capillary pressure data vs. water saturation (Pc–Sw as well as routine reservoir core analysis include porosity (φ and permeability (k were used to develop the J-function. First, the normalized porosity (φz, the rock quality index (RQI, and the flow zone indicator (FZI concepts were used to categorize all data into discrete hydraulic flow units (HFU containing unique pore geometry and bedding characteristics. Thereafter, the modified J-function was used to normalize all capillary pressure curves corresponding to each of predetermined HFU. The results showed that the reservoir rock was classified into five separate rock types with the definite HFU and reservoir pore geometry. Eventually, the pore radius for each of these HFUs was determined using a developed equation obtained by normalized J-function corresponding to each HFU. The proposed equation is a function of reservoir rock characteristics including φz, FZI, lithology index (J*, and pore size distribution index (ɛ. This methodology used, the reservoir under study was classified into five discrete HFU with unique equations for permeability, normalized J-function and pore size. The proposed technique is able to apply on any reservoir to determine the pore size of the reservoir rock, specially the one with high range of heterogeneity in the reservoir rock properties.

  1. Detection of rheumatoid arthritis by evaluation of normalized variances of fluorescence time correlation functions

    Science.gov (United States)

    Dziekan, Thomas; Weissbach, Carmen; Voigt, Jan; Ebert, Bernd; MacDonald, Rainer; Bahner, Malte L.; Mahler, Marianne; Schirner, Michael; Berliner, Michael; Berliner, Birgitt; Osel, Jens; Osel, Ilka

    2011-07-01

    Fluorescence imaging using the dye indocyanine green as a contrast agent was investigated in a prospective clinical study for the detection of rheumatoid arthritis. Normalized variances of correlated time series of fluorescence intensities describing the bolus kinetics of the contrast agent in certain regions of interest were analyzed to differentiate healthy from inflamed finger joints. These values are determined using a robust, parameter-free algorithm. We found that the normalized variance of correlation functions improves the differentiation between healthy joints of volunteers and joints with rheumatoid arthritis of patients by about 10% compared to, e.g., ratios of areas under the curves of raw data.

  2. Power Grid Protection of the Muscle Mitochondrial Reticulum

    Directory of Open Access Journals (Sweden)

    Brian Glancy

    2017-04-01

    Full Text Available Summary: Mitochondrial network connectivity enables rapid communication and distribution of potential energy throughout the cell. However, this connectivity puts the energy conversion system at risk, because damaged elements could jeopardize the entire network. Here, we demonstrate the mechanisms for mitochondrial network protection in heart and skeletal muscle (SKM. We find that the cardiac mitochondrial reticulum is segmented into subnetworks comprising many mitochondria linked through abundant contact sites at highly specific intermitochondrial junctions (IMJs. In both cardiac and SKM subnetworks, a rapid electrical and physical separation of malfunctioning mitochondria occurs, consistent with detachment of IMJs and retraction of elongated mitochondria into condensed structures. Regional mitochondrial subnetworks limit the cellular impact of local dysfunction while the dynamic disconnection of damaged mitochondria allows the remaining mitochondria to resume normal function within seconds. Thus, mitochondrial network security is comprised of both proactive and reactive mechanisms in striated muscle cells. : Network connectivity allows information sharing and distribution but also enables propagation of localized dysfunction. Glancy et al. demonstrate the existence of both proactive and reactive network protection mechanisms designed to minimize the spread of dysfunction throughout the coupled mitochondrial networks in heart and skeletal muscle cells. Keywords: energy distribution, muscle energetics, oxidative phosphorylation, 3D electron microscopy, mitochondrial retraction, mitochondrial dynamics

  3. Functional Mitochondrial Complex I Is Required by Tobacco Leaves for Optimal Photosynthetic Performance in Photorespiratory Conditions and during Transients1

    Science.gov (United States)

    Dutilleul, Christelle; Driscoll, Simon; Cornic, Gabriel; De Paepe, Rosine; Foyer, Christine H.; Noctor, Graham

    2003-01-01

    The importance of the mitochondrial electron transport chain in photosynthesis was studied using the tobacco (Nicotiana sylvestris) mutant CMSII, which lacks functional complex I. Rubisco activities and oxygen evolution at saturating CO2 showed that photosynthetic capacity in the mutant was at least as high as in wild-type (WT) leaves. Despite this, steady-state photosynthesis in the mutant was reduced by 20% to 30% at atmospheric CO2 levels. The inhibition of photosynthesis was alleviated by high CO2 or low O2. The mutant showed a prolonged induction of photosynthesis, which was exacerbated in conditions favoring photorespiration and which was accompanied by increased extractable NADP-malate dehydrogenase activity. Feeding experiments with leaf discs demonstrated that CMSII had a lower capacity than the WT for glycine (Gly) oxidation in the dark. Analysis of the postillumination burst in CO2 evolution showed that this was not because of insufficient Gly decarboxylase capacity. Despite the lower rate of Gly metabolism in CMSII leaves in the dark, the Gly to Ser ratio in the light displayed a similar dependence on photosynthesis to the WT. It is concluded that: (a) Mitochondrial complex I is required for optimal photosynthetic performance, despite the operation of alternative dehydrogenases in CMSII; and (b) complex I is necessary to avoid redox disruption of photosynthesis in conditions where leaf mitochondria must oxidize both respiratory and photorespiratory substrates simultaneously. PMID:12529534

  4. Alterations in mitochondrial function and spermatozoal motility in goat spermatozoa following incubation with a human lysozyme plasmid.

    Science.gov (United States)

    Ma, Huiming; Quan, Fusheng; Chen, Dongmei; Zhang, Bowei; Zhang, Yong

    2010-08-01

    Spermatozoa mediated gene transfer has become a promising technology to generate transgenic animals with disease resistance. However, exogenous DNA invasion may cause changes in spermatozoon natural defense system which result in spermatozoon dysfunction.The objective of this study was to investigate the changes of mitochondrial function and motility in goat spermatozoa after pre-incubation and incubation with and without the human lysozyme plasmid pFLAG-hLY. The results demonstrated that human lysozyme plasmid pFLAG-hLY could bind to the surface of the spermatozoon membrane at 186,000 copies/spermatozoa and incorporate to spermatozoon nucleus at 78 copies/spermatozoa after incubation. However, the treated spermatozoon samples showed a significant lower motility (29.7+/-2.2% vs. pre-incubation control 48.0+/-1.4% and incubation control 54.5+/-1.5%, P spermatozoon dysfunction. In conclusion, this study confirmed that goat spermatozoa could capture human lysozyme plasmid pFLAG-hLY,but the incubation with the plasmids resulted in a decrease of spermatozoa motility and partial rupture of mitochondrial membrane, and further prompted the expression of cytochrome c, and generation of oxidative stress in vitro and finally led to spermatozoon dysfunction.

  5. Clinical benefit of drugs targeting mitochondrial function as an adjunct to reperfusion in ST-segment elevation myocardial infarction

    DEFF Research Database (Denmark)

    Campo, Gianluca; Pavasini, Rita; Morciano, Giampaolo

    2017-01-01

    identified involving 5680 patients. When compared with placebo, drugs targeting mitochondrial component/pathway were not associated with significant reduction of cardiovascular and all-cause mortality (OR 0.9, 95% CI 0.7-1.17 and OR 0.92, 95% CI 0.69-1.23, respectively). However, these agents significantly......, those with indirect/unspecific action showed a significant effect on cardiovascular mortality (0.65, 95% CI 0.46-0.92), all-cause mortality (OR 0.69, 95% CI 0.52-0.92), hospital readmission for HF (OR 0.41, 95% CI 0.28-0.6) and LVEF (OR 1.49, 95% CI 1.09-2.05). CONCLUSIONS: Administration of drugs......AIMS: To perform a systematic review and meta-analysis of randomized clinical trials (RCT) comparing the effectiveness of drugs targeting mitochondrial function vs. placebo in patients with ST-segment elevation myocardial infarction (STEMI) undergoing mechanical coronary reperfusion. METHODS...

  6. Tumor microenvironment and metabolic synergy in breast cancers: critical importance of mitochondrial fuels and function.

    Science.gov (United States)

    Martinez-Outschoorn, Ubaldo; Sotgia, Federica; Lisanti, Michael P

    2014-04-01

    Metabolic synergy or metabolic coupling between glycolytic stromal cells (Warburg effect) and oxidative cancer cells occurs in human breast cancers and promotes tumor growth. The Warburg effect or aerobic glycolysis is the catabolism of glucose to lactate to obtain adenosine triphosphate (ATP). This review summarizes the main findings on this stromal metabolic phenotype, and the associated signaling pathways, as well as the critical role of oxidative stress and autophagy, all of which promote carcinoma cell mitochondrial metabolism and tumor growth. Loss of Caveolin 1 (Cav-1) and the upregulation of monocarboxylate transporter 4 (MCT4) in stromal cells are novel markers of the Warburg effect and metabolic synergy between stromal and carcinoma cells. MCT4 and Cav-1 are also breast cancer prognostic biomarkers. Reactive oxygen species (ROS) are key mediators of the stromal Warburg effect. High ROS also favors cancer cell mitochondrial metabolism and tumorigenesis, and anti-oxidants can reverse this altered stromal and carcinoma metabolism. A pseudo-hypoxic state with glycolysis and low mitochondrial metabolism in the absence of hypoxia is a common feature in breast cancer. High ROS induces loss of Cav-1 in stromal cells and is sufficient to generate a pseudo-hypoxic state. Loss of Cav-1 in the stroma drives glycolysis and lactate extrusion via HIF-1α stabilization and the upregulation of MCT4. Stromal cells with loss of Cav-1 and/or high expression of MCT4 also show a catabolic phenotype, with enhanced macroautophagy. This catabolic state in stromal cells is driven by hypoxia-inducible factor (HIF)-1α, nuclear factor κB (NFκB), and JNK activation and high ROS generation. A feed-forward loop in stromal cells regulates pseudo-hypoxia and metabolic synergy, with Cav-1, MCT4, HIF-1α, NFκB, and ROS as its key elements. Metabolic synergy also may occur between cancer cells and cells in distant organs from the tumor. Cancer cachexia, which is due to severe organismal

  7. A Mitochondria-Specific Isoform of FASTK Is Present In Mitochondrial RNA Granules and Regulates Gene Expression and Function

    Directory of Open Access Journals (Sweden)

    Alexis A. Jourdain

    2015-02-01

    Full Text Available The mitochondrial genome relies heavily on post-transcriptional events for its proper expression, and misregulation of this process can cause mitochondrial genetic diseases in humans. Here, we report that a novel translational variant of Fas-activated serine/threonine kinase (FASTK co-localizes with mitochondrial RNA granules and is required for the biogenesis of ND6 mRNA, a mitochondrial-encoded subunit of the NADH dehydrogenase complex (complex I. We show that ablating FASTK expression in cultured cells and mice results specifically in loss of ND6 mRNA and reduced complex I activity in vivo. FASTK binds at multiple sites along the ND6 mRNA and its precursors and cooperates with the mitochondrial degradosome to ensure regulated ND6 mRNA biogenesis. These data provide insights into the mechanism and control of mitochondrial RNA processing within mitochondrial RNA granules.

  8. Tubal transport of spermatozoa does not appear to be dependent on normal cilia function.

    Science.gov (United States)

    Ott, Helmut W; Schmiedehausen, Kristin; Kat, Sonja; Binder, Helge; Gall, Christian; Kuwert, Torsten; Heute, Dirk; Virgolini, Irene; Wildt, Ludwig

    2007-11-01

    To report the case of a woman with Kartagener's syndrome with complete immotility of ciliae and normal transport of spermatozoa. Case report. A 31-year-old woman with Kartagener's syndrome. Medical university-affiliated teaching hospital. Ultrasonography, hysterosalpingoscintigraphy using technetium-99m-labeled macroaggregates of human serum albumin, application of oxytocin. Dynamic anteroposterior scintigraphy using a gamma camera. The transport of labeled macrospheres through the fallopian tube into the peritoneal cavity on the side of the leading follicle, compared to the contralateral oviduct where the labeled material may have accumulated within the fallopian tube, is similar to those reported in normal fertile women. Transport of spermatozoa is not dependent on normal ciliary function.

  9. Catalase overexpression does not impair extensor digitorum longus muscle function in normal mice.

    Science.gov (United States)

    Liu, Mingju; Yue, Yongping; Li, Dejia; Duan, Dongsheng

    2007-12-01

    Catalase is a major antioxidant enzyme. Increasing catalase expression represents a promising avenue to improve muscle function in certain physiological conditions and in some muscle diseases. We hypothesized that catalase overexpression should not impair normal muscle contraction. We delivered a hemagglutinin (HA)-tagged human catalase gene to normal mouse muscle by an adeno-associated viral vector (AAV). Western blot and immunostaining revealed efficient expression of HA-tagged catalase. Enzymatic assay demonstrated an approximately threefold increase in catalase activity in AAV-infected muscles. Catalase overexpression impaired neither twitch nor tetanic tension in the extensor digitorum longus (EDL) muscle. Furthermore, EDL fatigue response was not altered. Taken together, we have developed a novel AAV vector to enhance catalase expression. Lack of apparent toxicity in normal muscle strongly supports further exploration of this vector to reduce oxidative stress-induced muscle damage.

  10. Normal Forms for Retarded Functional Differential Equations and Applications to Bogdanov-Takens Singularity

    Science.gov (United States)

    Faria, T.; Magalhaes, L. T.

    The paper addresses, for retarded functional differential equations (FDEs), the computation of normal forms associated with the flow on a finite-dimensional invariant manifold tangent to invariant spaces for the infinitesimal generator of the linearized equation at a singularity. A phase space appropriate to the computation of these normal forms is introduced, and adequate nonresonance conditions for the computation of the normal forms are derived. As an application, the general situation of Bogdanov-Takens singularity and its versal unfolding for scalar retarded FDEs with nondegeneracy at second order is considered, both in the general case and in the case of differential-delay equations of the form ẋ( t) = ƒ( x( t), x( t-1)).

  11. Nonclinical and pharmacokinetic assessments to evaluate the potential of tedizolid and linezolid to affect mitochondrial function.

    Science.gov (United States)

    Flanagan, Shawn; McKee, Edward E; Das, Debaditya; Tulkens, Paul M; Hosako, Hiromi; Fiedler-Kelly, Jill; Passarell, Julie; Radovsky, Ann; Prokocimer, Philippe

    2015-01-01

    Prolonged treatment with the oxazolidinone linezolid is associated with myelosuppression, lactic acidosis, and neuropathies, toxicities likely caused by impairment of mitochondrial protein synthesis (MPS). To evaluate the potential of the novel oxazolidinone tedizolid to cause similar side effects, nonclinical and pharmacokinetic assessments were conducted. In isolated rat heart mitochondria, tedizolid inhibited MPS more potently than did linezolid (average [± standard error of the mean] 50% inhibitory concentration [IC50] for MPS of 0.31 ± 0.02 μM versus 6.4 ± 1.2 μM). However, a rigorous 9-month rat study comparing placebo and high-dose tedizolid (resulting in steady-state area under the plasma concentration-time curve values about 8-fold greater than those with the standard therapeutic dose in humans) showed no evidence of neuropathy. Additional studies explored why prolonged, high-dose tedizolid did not cause these mitochondriopathic side effects despite potent MPS inhibition by tedizolid. Murine macrophage (J774) cell fractionation studies found no evidence of a stable association of tedizolid with eukaryotic mitochondria. Monte Carlo simulations based on population pharmacokinetic models showed that over the course of a dosing interval using standard therapeutic doses, free plasma concentrations fell below the respective MPS IC50 in 84% of tedizolid-treated patients (for a median duration of 7.94 h) and 38% of linezolid-treated patients (for a median duration of 0 h). Therapeutic doses of tedizolid, but not linezolid, may therefore allow for mitochondrial recovery during antibacterial therapy. The overall results suggest that tedizolid has less potential to cause myelosuppression and neuropathy than that of linezolid during prolonged treatment courses. This, however, remains a hypothesis that must be confirmed in clinical studies. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  12. Functional crosstalk between the mitochondrial PTP and KATP channels determine arrhythmic vulnerability to oxidative stress

    Directory of Open Access Journals (Sweden)

    Chaoqin eXie

    2014-07-01

    Full Text Available Permeability transition pore (mPTP opening leads to mitochondrial dysfunction & cell death during oxidative stress (OS. However mPTP desensitization with cyclosporine A (CsA has shown variable efficacy in limiting post-ischemic arrhythmias. We hypothesized that feedback between energy dissipating (mPTP and cardioprotective (mKATP channels determine vulnerability to OS.Methods & Results: Guinea pig hearts (N=61 were perfused with H2O2 to elicit mitochondrial membrane potential (MMP depolarization. Optical mapping was used to measure MMP or action potentials (AP. Hearts were treated with CsA under conditions that altered mKATP activity directly or indirectly via its regulation by PKC. CsA blunted OS-induced MMP depolarization and delayed loss of contractility but did not affect arrhythmia propensity. Surprisingly, prevention of mKATP activation with the phosphatase BDM reversed the protective effect of CsA, paradoxically exacerbating OS-induced MMP depolarization and accelerating arrhythmia onset in CsA treated hearts. To elucidate the putative molecular mechanisms, mPTP inhibition by CsA was tested under conditions of selective PKC inhibition, mKATP activation or blockade. Similar to BDM, CHE did not alter OS-induced MMP depolarization. However, it completely abrogated CsA-mediated protection against OS. Pharmacological block of mKATP, a target of PKC signaling, equally abolished the protective effect of CsA on MMP depolarization, whereas channel activation with DZX protected against MMP depolarization. Conditions that prevented mKATP activation led to accelerated MMP depolarization and early onset of VF in response to OS. Investigation of the electrophysiological substrate revealed accelerated APD shortening in response to OS in arrhythmia-prone hearts.Conclusions: Cardioprotection by CsA requires mKATP activation through a PKC-dependent pathway. Increasing mKATP activity during CsA administration is required for limiting OS-induced electrical

  13. Preservation of Cognitive Function by Lepidium meyenii (Maca) Is Associated with Improvement of Mitochondrial Activity and Upregulation of Autophagy-Related Proteins in Middle-Aged Mouse Cortex.

    Science.gov (United States)

    Guo, Shan-Shan; Gao, Xiao-Fang; Gu, Yan-Rong; Wan, Zhong-Xiao; Lu, A-Ming; Qin, Zheng-Hong; Luo, Li

    2016-01-01

    Maca has been used as a foodstuff and a traditional medicine in the Andean region for over 2,000 years. Recently the neuroprotective effects of maca also arouse interest of researchers. Decrease in mitochondrial function and decline in autophagy signaling may participate in the process of age-related cognitive decline. This study aimed to investigate if maca could improve cognitive function of middle-aged mice and if this effect was associated with improvement of mitochondrial activity and modulation of autophagy signaling in mouse cortex. Fourteen-month-old male ICR mice received maca powder administered by gavage for five weeks. Maca improved cognitive function, motor coordination, and endurance capacity in middle-aged mice, accompanied by increased mitochondrial respiratory function and upregulation of autophagy-related proteins in cortex. Our findings suggest that maca is a newly defined nutritional plant which can improve mitochondrial function and upregulate autophagy-related proteins and may be an effective functional food for slowing down age-related cognitive decline.

  14. Preservation of Cognitive Function by Lepidium meyenii (Maca Is Associated with Improvement of Mitochondrial Activity and Upregulation of Autophagy-Related Proteins in Middle-Aged Mouse Cortex

    Directory of Open Access Journals (Sweden)

    Shan-Shan Guo

    2016-01-01

    Full Text Available Maca has been used as a foodstuff and a traditional medicine in the Andean region for over 2,000 years. Recently the neuroprotective effects of maca also arouse interest of researchers. Decrease in mitochondrial function and decline in autophagy signaling may participate in the process of age-related cognitive decline. This study aimed to investigate if maca could improve cognitive function of middle-aged mice and if this effect was associated with improvement of mitochondrial activity and modulation of autophagy signaling in mouse cortex. Fourteen-month-old male ICR mice received maca powder administered by gavage for five weeks. Maca improved cognitive function, motor coordination, and endurance capacity in middle-aged mice, accompanied by increased mitochondrial respiratory function and upregulation of autophagy-related proteins in cortex. Our findings suggest that maca is a newly defined nutritional plant which can improve mitochondrial function and upregulate autophagy-related proteins and may be an effective functional food for slowing down age-related cognitive decline.

  15. Lung function not affected by asbestos exposure in workers with normal Computed Tomography scan.

    Science.gov (United States)

    Schikowsky, Christian; Felten, Michael K; Eisenhawer, Christian; Das, Marco; Kraus, Thomas

    2017-05-01

    It has been suggested that asbestos exposure affects lung function, even in the absence of asbestos-related pulmonary interstitial or pleural changes or emphysema. We analyzed associations between well-known asbestos-related risk factors, such as individual cumulative asbestos exposure, and key lung function parameters in formerly asbestos-exposed power industry workers (N = 207) with normal CT scans. For this, we excluded participants with emphysema, fibrosis, pleural changes, or any combination of these. The lung function parameters of FVC, FEV1, DLCO/VA, and airway resistance were significantly associated with the burden of smoking, BMI and years since end of exposure (only DLCO/VA). However, they were not affected by factors directly related to amount (eg, cumulative exposure) or duration of asbestos exposure. Our results confirm the well-known correlation between lung function, smoking habits, and BMI. However, we found no significant association between lung function and asbestos exposure. © 2017 Wiley Periodicals, Inc.

  16. Reduced mitochondrial mass and function add to age-related susceptibility toward diet-induced fatty liver in C57BL/6J mice.

    Science.gov (United States)

    Lohr, Kerstin; Pachl, Fiona; Moghaddas Gholami, Amin; Geillinger, Kerstin E; Daniel, Hannelore; Kuster, Bernhard; Klingenspor, Martin

    2016-10-01

    Nonalcoholic fatty liver disease (NAFLD) is a major health burden in the aging society with an urging medical need for a better understanding of the underlying mechanisms. Mitochondrial fatty acid oxidation and mitochondrial-derived reactive oxygen species (ROS) are considered critical in the development of hepatic steatosis, the hallmark of NAFLD. Our study addressed in C57BL/6J mice the effect of high fat diet feeding and age on liver mitochondria at an early stage of NAFLD development. We therefore analyzed functional characteristics of hepatic mitochondria and associated alterations in the mitochondrial proteome in response to high fat feeding in adolescent, young adult, and middle-aged mice. Susceptibility to diet-induced obesity increased with age. Young adult and middle-aged mice developed fatty liver, but not adolescent mice. Fat accumulation was negatively correlated with an age-related reduction in mitochondrial mass and aggravated by a reduced capacity of fatty acid oxidation in high fat-fed mice. Irrespective of age, high fat diet increased ROS production in hepatic mitochondria associated with a balanced nuclear factor erythroid-derived 2 like 2 (NFE2L2) dependent antioxidative response, most likely triggered by reduced tethering of NFE2L2 to mitochondrial phosphoglycerate mutase 5. Age indirectly influenced mitochondrial function by reducing mitochondrial mass, thus exacerbating diet-induced fat accumulation. Therefore, consideration of age in metabolic studies must be emphasized. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  17. CT Densitometry of the Lung in Healthy Nonsmokers with Normal Pulmonary Function

    International Nuclear Information System (INIS)

    Oh, Tack Sun; Chae, Eun Jin; Seo, Joon Beom; Jung, Young Ju; Oh, Yeon Mok; Lee, Sang Do

    2012-01-01

    To investigate the upper normal limit of low attenuation area in healthy nonsmokers. A total of 36 nonsmokers with normal pulmonary function test underwent a CT scan. Six thresholds (-980 --930 HU) on inspiration CT and two thresholds (-950 and -910 HU) on expiration CT were used for obtaining low attenuation area. The mean lung density was obtained on both inspiration CT and expiration CT. Descriptive statistics of low attenuation area and the mean lung density, evaluation of difference of low attenuation area and the mean lung density in both sex and age groups, analysis of the relationship between demographic information and CT parameters were performed. Upper normal limit for low attenuation area was 12.96% on inspiration CT (-950 HU) and 9.48% on expiration CT (-910 HU). Upper normal limit for the mean lung density was -837.58 HU on inspiration CT and 686.82 HU on expiration CT. Low attenuation area and the mean lung density showed no significant differences in both sex and age groups. Body mass index (BMI) was negatively correlated with low attenuation area on inspiration CT (-950 HU, r = -0.398, p = 0.016) and positively correlated with the mean lung density on inspiration CT (r 0.539, p = 0.001) and expiration CT (r = 0.432, p = 0.009). Age and body surface area were not correlated with low attenuation area or the mean lung density. Low attenuation area on CT densitometry of the lung could be found in healthy nonsmokers with normal pulmonary function, and showed negative association with BMI. Reference values, such as range and upper normal limit for low attenuation area in healthy subjects could be helpful in quantitative analysis and follow up of early emphysema, using CT densitometry of the lung.

  18. CT Densitometry of the Lung in Healthy Nonsmokers with Normal Pulmonary Function

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Tack Sun; Chae, Eun Jin; Seo, Joon Beom; Jung, Young Ju; Oh, Yeon Mok; Lee, Sang Do [University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

    2012-09-15

    To investigate the upper normal limit of low attenuation area in healthy nonsmokers. A total of 36 nonsmokers with normal pulmonary function test underwent a CT scan. Six thresholds (-980 --930 HU) on inspiration CT and two thresholds (-950 and -910 HU) on expiration CT were used for obtaining low attenuation area. The mean lung density was obtained on both inspiration CT and expiration CT. Descriptive statistics of low attenuation area and the mean lung density, evaluation of difference of low attenuation area and the mean lung density in both sex and age groups, analysis of the relationship between demographic information and CT parameters were performed. Upper normal limit for low attenuation area was 12.96% on inspiration CT (-950 HU) and 9.48% on expiration CT (-910 HU). Upper normal limit for the mean lung density was -837.58 HU on inspiration CT and 686.82 HU on expiration CT. Low attenuation area and the mean lung density showed no significant differences in both sex and age groups. Body mass index (BMI) was negatively correlated with low attenuation area on inspiration CT (-950 HU, r = -0.398, p = 0.016) and positively correlated with the mean lung density on inspiration CT (r 0.539, p = 0.001) and expiration CT (r = 0.432, p = 0.009). Age and body surface area were not correlated with low attenuation area or the mean lung density. Low attenuation area on CT densitometry of the lung could be found in healthy nonsmokers with normal pulmonary function, and showed negative association with BMI. Reference values, such as range and upper normal limit for low attenuation area in healthy subjects could be helpful in quantitative analysis and follow up of early emphysema, using CT densitometry of the lung.

  19. Executive Functions of Six-Year-Old Boys with Normal Birth Weight and Gestational Age

    Science.gov (United States)

    Phua, Desiree Yee-Ling; Rifkin-Graboi, Anne; Saw, Seang-Mei; Meaney, Michael J.; Qiu, Anqi

    2012-01-01

    Impaired fetal development, reflected by low birth weight or prematurity, predicts an increased risk for psychopathology, especially attention deficit hyperactivity disorder (ADHD). Such effects cut across the normal range of birth weight and gestation. Despite the strength of existing epidemiological data, cognitive pathways that link fetal development to mental health are largely unknown. In this study we examined the relation of birth weight (>2500 g) and gestational age (37–41 weeks) within the normal range with specific executive functions in 195 Singaporean six-year-old boys of Chinese ethnicity. Birth weight adjusted for gestational age was used as indicator of fetal growth while gestational age was indicative of fetal maturity. Linear regression revealed that increased fetal growth within the normal range is associated with an improved ability to learn rules during the intra/extra-dimensional shift task and to retain visual information for short period of time during the delayed matching to sample task. Moreover, faster and consistent reaction times during the stop-signal task were observed among boys born at term, but with higher gestational age. Hence, even among boys born at term with normal birth weight, variations in fetal growth and maturity showed distinct effects on specific executive functions. PMID:22558470

  20. Prevalence of normal TSH value among patients with autonomously functioning thyroid nodule.

    Science.gov (United States)

    Treglia, Giorgio; Trimboli, Pierpaolo; Verburg, Frederik A; Luster, Markus; Giovanella, Luca

    2015-07-01

    International guidelines significantly diverge on the effectiveness of thyroid scintigraphy (TS) in the initial work-up of thyroid nodules. In particular, the role of TS to detect or exclude the presence of autonomously functioning thyroid nodules (AFTN) in patients with normal serum thyrotropin (TSH) is still a matter to debate. Here, we aimed to review the literature on the prevalence of normal TSH value among patients with AFTN and meta-analyse data of the retrieved eligible papers. A comprehensive literature search of studies published from January 2000 to December 2014 on AFTN detected by TS was performed. Records reporting serum TSH values in AFTN were selected. Pooled prevalence of AFTN with normal TSH values was calculated on a per-patient analysis including 95% confidence intervals (95% CI). Eight records including 2761 AFTN were selected for the meta-analysis. Pooled prevalence of AFTN with normal TSH detected by TS was 50% (95% CI: 32-68%). Selection bias in the included studies and heterogeneity among studies were potential limitations of the meta-analysis. Present meta-analysis shows that about one in two patients with AFTN demonstrated by TS has a TSH value within normal references. As a consequence, TSH measurement may not be considered as effective as a single tool to detect or exclude AFTN, and TS remains mandatory. © 2015 Stichting European Society for Clinical Investigation Journal Foundation.

  1. Genome-wide and functional annotation of human E3 ubiquitin ligases identifies MULAN, a mitochondrial E3 that regulates the organelle's dynamics and signaling.

    Directory of Open Access Journals (Sweden)

    Wei Li

    2008-01-01

    Full Text Available Specificity of protein ubiquitylation is conferred by E3 ubiquitin (Ub ligases. We have annotated approximately 617 putative E3s and substrate-recognition subunits of E3 complexes encoded in the human genome. The limited knowledge of the function of members of the large E3 superfamily prompted us to generate genome-wide E3 cDNA and RNAi expression libraries designed for functional screening. An imaging-based screen using these libraries to identify E3s that regulate mitochondrial dynamics uncovered MULAN/FLJ12875, a RING finger protein whose ectopic expression and knockdown both interfered with mitochondrial trafficking and morphology. We found that MULAN is a mitochondrial protein - two transmembrane domains mediate its localization to the organelle's outer membrane. MULAN is oriented such that its E3-active, C-terminal RING finger is exposed to the cytosol, where it has access to other components of the Ub system. Both an intact RING finger and the correct subcellular localization were required for regulation of mitochondrial dynamics, suggesting that MULAN's downstream effectors are proteins that are either integral to, or associated with, mitochondria and that become modified with Ub. Interestingly, MULAN had previously been identified as an activator of NF-kappaB, thus providing a link between mitochondrial dynamics and mitochondria-to-nucleus signaling. These findings suggest the existence of a new, Ub-mediated mechanism responsible for integration of mitochondria into the cellular environment.

  2. Mitochondrial Diseases

    Science.gov (United States)

    ... disorder, something goes wrong with this process. Mitochondrial diseases are a group of metabolic disorders. Mitochondria are ... cells and cause damage. The symptoms of mitochondrial disease can vary. It depends on how many mitochondria ...

  3. Age and Gender Effects on Wideband Absorbance in Adults with Normal Outer and Middle Ear Function

    Science.gov (United States)

    Mazlan, Rafidah; Kei, Joseph; Ya, Cheng Li; Yusof, Wan Nur Hanim Mohd; Saim, Lokman; Zhao, Fei

    2015-01-01

    Purpose: This study examined the effects of age and gender on wideband energy absorbance in adults with normal middle ear function. Method: Forty young adults (14 men, 26 women, aged 20-38 years), 31 middle-aged adults (16 men, 15 women, aged 42-64 years), and 30 older adults (20 men, 10 women, aged 65-82 years) were assessed. Energy absorbance…

  4. Amitriptyline improves motor function via enhanced neurotrophin signaling and mitochondrial functions in the murine N171-82Q Huntington disease model.

    Science.gov (United States)

    Cong, Wei-Na; Chadwick, Wayne; Wang, Rui; Daimon, Caitlin M; Cai, Huan; Amma, Jennifer; Wood, William H; Becker, Kevin G; Martin, Bronwen; Maudsley, Stuart

    2015-01-30

    Huntington disease (HD) is a neurodegenerative disorder characterized by progressive motor impairment and cognitive alterations. Hereditary HD is primarily caused by the expansion of a CAG trinucleotide repeat in the huntingtin (Htt) gene, which results in the production of mutant huntingtin protein (mHTT) with an expanded amino-terminal polyglutamine (poly(Q)) stretch. Besides pathological mHTT aggregation, reduced brain-derived neurotrophic factor (BDNF) levels, impaired neurotrophin signaling, and compromised mitochondrial functions also contribute to the deleterious progressive etiology of HD. As a well tolerated Food and Drug Administration-approved antidepressant, amitriptyline (AMI) has shown efficacy in treating neurodegenerative murine models via potentiation of BDNF levels and amelioration of alterations in neurotrophin signaling pathways. In this study, we observed profound improvements in the motor coordination of AMI-treated N171-82Q HD model mice. The beneficial effects of AMI treatment were associated with its ability to reduce mHTT aggregation, potentiation of the BDNF-TrkB signaling system, and support of mitochondrial integrity and functionality. Our study not only provides preclinical evidence for the therapeutic potency of AMI in treating HD, but it also represents an important example of the usefulness of additional pharmacogenomic profiling of pre-existing drugs for novel therapeutic effects with often intractable pathological scenarios. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. A f-MRI study on memory function in normal subjects and patients with partial epilepsies

    International Nuclear Information System (INIS)

    Kamoda, Sachiko

    2004-01-01

    To investigate cerebral regions concerning a memory function and presence of memory lateralization, activated areas and the difference between the right and left hemisphere in functional magnetic resonance imaging (f-MRI) during verbal and visual memory tasks were examined in normal subjects and, as its clinical application, in patients with partial epilepsies. Subjects were 39 normal adult subjects and 10 adult patients. Of the 39 normal subjects, 30 were right-handed and 9 were left-handed. Further, of the 10 patients, 9 were right-handed and one was left-handed, and 7, 2 and 1 had temporal lobe, frontal lobe and undetermined partial epilepsies, respectively. Following the three type of memory task were designed; verbal memory tasks consisting of covert and overt recall tests of 10 words given auditory and visual memory task of covert recall tasks of 6 figures given visually. Activated cerebral areas were imaged with f-MRI using 1.5 tesla Magnetom Vision taken repeatedly during these tasks and neutral condition. Most of the 30 right-handed normal subjects showed activated areas over the left hemisphere specifically on the anterior cingulate, superior, middle and inferior frontal gyri during the verbal memory tasks of covert recall tests. Left hemisphere dominant activated areas in the precentral gyri were added during the verbal memory tasks of overt recall tests. On the other hand, 4 of the 9 left-handed normal subjects showed the left side-dominantly activated areas in the above-mentioned regions during the verbal memory tasks of covert and overt tests, in common with the right-handed subjects. However, 3 of the 9 left-handed normal subjects had right hemisphere dominant activation during the verbal memory tasks, while none of the 30 right-handed normal subjects showed such right side-dominancy. Further, the bilateral occipital lobes were activated during visual memory tasks. The reproducibility in this activation during these verbal and visual memory tasks

  6. Relationship between Stroop performance and resting state functional connectivity in cognitively normal older adults.

    Science.gov (United States)

    Duchek, Janet M; Balota, David A; Thomas, Jewell B; Snyder, Abraham Z; Rich, Patrick; Benzinger, Tammie L; Fagan, Anne M; Holtzman, David M; Morris, John C; Ances, Beau M

    2013-09-01

    Early biomarkers of Alzheimer's disease (AD) are needed for developing therapeutic interventions. Measures of attentional control in Stroop-type tasks discriminate healthy aging from early stage AD and predict future development of AD in cognitively normal individuals. Disruption in resting state functional connectivity MRI (rs-fcMRI) has been reported in AD and in healthy controls at risk for AD. We explored the relationship among Stroop performance, rs-fcMRI, and CSF Aβ₄₂ levels in cognitively normal older adults. A computerized Stroop task (along with standard neuropsychological measures), rs-fcMRI, and CSF were obtained in 237 cognitively normal older adults. We compared the relationship between Stroop performance, including measures from reaction distributional analyses, and composite scores from four resting state networks (RSNs; default mode [DMN], salience [SAL], dorsal attention [DAN], and sensory-motor [SMN]), and the modulatory influence of CSF Aβ₄₂ levels. A larger Stroop effect in errors was associated with reduced rs-fcMRI within the DMN and SAL. Reaction time (RT) distributional analyses indicated the slow tail of the RT distribution was related to reduced rs-fcMRI functional connectivity within the SAL. Standard psychometric measures were not related to RSN composite scores. A relationship between Stroop performance and DMN (but not SAL) functional connectivity was stronger in CSF Aβ₄₂-positive individuals. A link exists between RSN composite scores and specific attentional performance measures. Both measures may be sensitive biomarkers for AD.

  7. A Soft Parameter Function Penalized Normalized Maximum Correntropy Criterion Algorithm for Sparse System Identification

    Directory of Open Access Journals (Sweden)

    Yingsong Li

    2017-01-01

    Full Text Available A soft parameter function penalized normalized maximum correntropy criterion (SPF-NMCC algorithm is proposed for sparse system identification. The proposed SPF-NMCC algorithm is derived on the basis of the normalized adaptive filter theory, the maximum correntropy criterion (MCC algorithm and zero-attracting techniques. A soft parameter function is incorporated into the cost function of the traditional normalized MCC (NMCC algorithm to exploit the sparsity properties of the sparse signals. The proposed SPF-NMCC algorithm is mathematically derived in detail. As a result, the proposed SPF-NMCC algorithm can provide an efficient zero attractor term to effectively attract the zero taps and near-zero coefficients to zero, and, hence, it can speed up the convergence. Furthermore, the estimation behaviors are obtained by estimating a sparse system and a sparse acoustic echo channel. Computer simulation results indicate that the proposed SPF-NMCC algorithm can achieve a better performance in comparison with the MCC, NMCC, LMS (least mean square algorithms and their zero attraction forms in terms of both convergence speed and steady-state performance.

  8. Functional pulmonary atresia in newborn with normal intracardiac anatomy: Successful treatment with inhaled nitric oxide and pulmonary vasodilators

    Directory of Open Access Journals (Sweden)

    Gürkan Altun

    2013-01-01

    Full Text Available Functional pulmonary atresia is characterized by a structurally normal pulmonary valve that does not open during right ventricular ejection. It is usually associated with Ebstein′s anomaly, Uhl′s anomaly, neonatal Marfan syndrome and tricuspid valve dysplasia. However, functional pulmonary atresia is rarely reported in newborn with anatomically normal heart. We report a newborn with functional pulmonary atresia who had normal intracardiac anatomy, who responded to treatment with nitric oxide and other vasodilator therapy successfully.

  9. GLP-1-RA Corrects Mitochondrial Labile Iron Accumulation and Improves β-Cell Function in Type 2 Wolfram Syndrome.

    Science.gov (United States)

    Danielpur, Liron; Sohn, Yang-Sung; Karmi, Ola; Fogel, Chen; Zinger, Adar; Abu-Libdeh, Abdulsalam; Israeli, Tal; Riahi, Yael; Pappo, Orit; Birk, Ruth; Zangen, David H; Mittler, Ron; Cabantchik, Zvi-Ioav; Cerasi, Erol; Nechushtai, Rachel; Leibowitz, Gil

    2016-10-01

    Type 2 Wolfram syndrome (T2-WFS) is a neuronal and β-cell degenerative disorder caused by mutations in the CISD2 gene. The mechanisms underlying β-cell dysfunction in T2-WFS are not known, and treatments that effectively improve diabetes in this context are lacking. Unraveling the mechanisms of β-cell dysfunction in T2-WFS and the effects of treatment with GLP-1 receptor agonist (GLP-1-RA). A case report and in vitro mechanistic studies. We treated an insulin-dependent T2-WFS patient with the GLP-1-RA exenatide for 9 weeks. An iv glucose/glucagon/arginine stimulation test was performed off-drug before and after intervention. We generated a cellular model of T2-WFS by shRNA knockdown of CISD2 (nutrient-deprivation autophagy factor-1 [NAF-1]) in rat insulinoma cells and studied the mechanisms of β-cell dysfunction and the effects of GLP-1-RA. Treatment with exenatide resulted in a 70% reduction in daily insulin dose with improved glycemic control, as well as an off-drug 7-fold increase in maximal insulin secretion. NAF-1 repression in INS-1 cells decreased insulin content and glucose-stimulated insulin secretion, while maintaining the response to cAMP, and enhanced the accumulation of labile iron and reactive oxygen species in mitochondria. Remarkably, treatment with GLP-1-RA and/or the iron chelator deferiprone reversed these defects. NAF-1 deficiency leads to mitochondrial labile iron accumulation and oxidative stress, which may contribute to β-cell dysfunction in T2-WFS. Treatment with GLP-1-RA and/or iron chelation improves mitochondrial function and restores β-cell function. Treatment with GLP-1-RA, probably aided by iron chelation, should be considered in WFS and other forms of diabetes associated with iron dysregulation.

  10. Slow recovery of the impaired fatigue resistance in postunloading mouse soleus muscle corresponding to decreased mitochondrial function and a compensatory increase in type I slow fibers

    Science.gov (United States)

    Feng, Han-Zhong; Chen, Xuequn; Malek, Moh H.

    2015-01-01

    Unloading or disuse rapidly results in skeletal muscle atrophy, switching to fast-type fibers, and decreased resistance to fatigue. The recovery process is of major importance in rehabilitation for various clinical conditions. Here we studied mouse soleus muscle during 60 days of reloading after 4 wk of hindlimb suspension. Unloading produced significant atrophy of soleus muscle with decreased contractile force and fatigue resistance, accompanied by switches of myosin isoforms from IIa to IIx and IIb and fast troponin T to more low-molecular-weight splice forms. The total mass, fiber size, and contractile force of soleus muscle recovered to control levels after 15 days of reloading. However, the fatigue resistance showed a trend of worsening during this period with significant infiltration of inflammatory cells at days 3 and 7, indicating reloading injuries that were accompanied by active regeneration with upregulations of filamin-C, αB-crystallin, and desmin. The fatigue resistance partially recovered after 30–60 days of reloading. The expression of peroxisome proliferator-activated receptor γ coactivator 1α and mitofusin-2 showed changes parallel to that of fatigue resistance after unloading and during reloading, suggesting a causal role of decreased mitochondrial function. Slow fiber contents in the soleus muscle were increased after 30–60 days of reloading to become significantly higher than the normal level, indicating a secondary adaption to compensate for the slow recovery of fatigue resistance. PMID:26447205

  11. Carcinogenesis: alterations in reciprocal interactions of normal functional structure of biologic systems.

    Science.gov (United States)

    Davydyan, Garri

    2015-12-01