WorldWideScience

Sample records for human mitochondrial diseases

  1. Melatonin and human mitochondrial diseases

    Directory of Open Access Journals (Sweden)

    Reza Sharafati-Chaleshtori

    2017-01-01

    Full Text Available Mitochondrial dysfunction is one of the main causative factors in a wide variety of complications such as neurodegenerative disorders, ischemia/reperfusion, aging process, and septic shock. Decrease in respiratory complex activity, increase in free radical production, increase in mitochondrial synthase activity, increase in nitric oxide production, and impair in electron transport system and/or mitochondrial permeability are considered as the main factors responsible for mitochondrial dysfunction. Melatonin, the pineal gland hormone, is selectively taken up by mitochondria and acts as a powerful antioxidant, regulating the mitochondrial bioenergetic function. Melatonin increases the permeability of membranes and is the stimulator of antioxidant enzymes including superoxide dismutase, glutathione peroxidase, glutathione reductase, and catalase. It also acts as an inhibitor of lipoxygenase. Melatonin can cause resistance to oxidation damage by fixing the microsomal membranes. Melatonin has been shown to retard aging and inhibit neurodegenerative disorders, ischemia/reperfusion, septic shock, diabetes, cancer, and other complications related to oxidative stress. The purpose of the current study, other than introducing melatonin, was to present the recent findings on clinical effects in diseases related to mitochondrial dysfunction including diabetes, cancer, gastrointestinal diseases, and diseases related to brain function.

  2. Mitochondrial Fusion Proteins and Human Diseases

    Directory of Open Access Journals (Sweden)

    Michela Ranieri

    2013-01-01

    Full Text Available Mitochondria are highly dynamic, complex organelles that continuously alter their shape, ranging between two opposite processes, fission and fusion, in response to several stimuli and the metabolic demands of the cell. Alterations in mitochondrial dynamics due to mutations in proteins involved in the fusion-fission machinery represent an important pathogenic mechanism of human diseases. The most relevant proteins involved in the mitochondrial fusion process are three GTPase dynamin-like proteins: mitofusin 1 (MFN1 and 2 (MFN2, located in the outer mitochondrial membrane, and optic atrophy protein 1 (OPA1, in the inner membrane. An expanding number of degenerative disorders are associated with mutations in the genes encoding MFN2 and OPA1, including Charcot-Marie-Tooth disease type 2A and autosomal dominant optic atrophy. While these disorders can still be considered rare, defective mitochondrial dynamics seem to play a significant role in the molecular and cellular pathogenesis of more common neurodegenerative diseases, for example, Alzheimer’s and Parkinson’s diseases. This review provides an overview of the basic molecular mechanisms involved in mitochondrial fusion and focuses on the alteration in mitochondrial DNA amount resulting from impairment of mitochondrial dynamics. We also review the literature describing the main disorders associated with the disruption of mitochondrial fusion.

  3. Comparative mitochondrial proteomics: perspective in human diseases

    Directory of Open Access Journals (Sweden)

    Jiang Yujie

    2012-03-01

    Full Text Available Abstract Mitochondria are the most complex and the most important organelles of eukaryotic cells, which are involved in many cellular processes, including energy metabolism, apoptosis, and aging. And mitochondria have been identified as the "hot spot" by researchers for exploring relevant associated dysfunctions in many fields. The emergence of comparative proteomics enables us to have a close look at the mitochondrial proteome in a comprehensive and effective manner under various conditions and cellular circumstances. Two-dimensional electrophoresis combined with mass spectrometry is still the most popular techniques to study comparative mitochondrial proteomics. Furthermore, many new techniques, such as ICAT, MudPIT, and SILAC, equip researchers with more flexibilities inselecting proper methods. This article also reviews the recent development of comparative mitochondrial proteomics on diverse human diseases. And the results of mitochondrial proteomics enhance a better understanding of the pathogenesis associated with mitochondria and provide promising therapeutic targets.

  4. Mitochondrial regulation of epigenetics and its role in human diseases

    DEFF Research Database (Denmark)

    Minocherhomji, Sheroy; Tollefsbol, Trygve O; Singh, Keshav K

    2012-01-01

    as the sole pathogenic factor suggesting that additional mechanisms contribute to lack of genotype and clinical phenotype correlationship. An increasing number of studies have identified a possible effect on the epigenetic landscape of the nuclear genome as a consequence of mitochondrial dysfunction....... In particular, these studies demonstrate reversible or irreversible changes in genomic DNA methylation profiles of the nuclear genome. Here we review how mitochondria damage checkpoint (mitocheckpoint) induces epigenetic changes in the nucleus. Persistent pathogenic mutations in mtDNA may also lead...... to epigenetic changes causing genomic instability in the nuclear genome. We propose that "mitocheckpoint" mediated epigenetic and genetic changes may play key roles in phenotypic variation related to mitochondrial diseases or host of human diseases in which mitochondrial defect plays a primary role....

  5. A novel diagnostic tool reveals mitochondrial pathology in human diseases and aging

    DEFF Research Database (Denmark)

    Scheibye-Knudsen, Morten; Scheibye-Alsing, Karsten; Canugovi, Chandrika

    2013-01-01

    to have mitochondrial dysfunction and those diseases showed strong association with mitochondrial disorders. We next evaluated mitochondrial involvement in aging and detected two distinct categories of accelerated aging disorders, one of them being associated with mitochondrial dysfunction. Normal aging...... seemed to associate stronger with the mitochondrial diseases than the non-mitochondrial partially supporting a mitochondrial theory of aging....

  6. Bacteria, Yeast, Worms, and Flies: Exploiting Simple Model Organisms to Investigate Human Mitochondrial Diseases

    Science.gov (United States)

    Rea, Shane L.; Graham, Brett H.; Nakamaru-Ogiso, Eiko; Kar, Adwitiya; Falk, Marni J.

    2010-01-01

    The extensive conservation of mitochondrial structure, composition, and function across evolution offers a unique opportunity to expand our understanding of human mitochondrial biology and disease. By investigating the biology of much simpler model organisms, it is often possible to answer questions that are unreachable at the clinical level.…

  7. 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

  8. Mitochondrial disease and epilepsy.

    Science.gov (United States)

    Rahman, Shamima

    2012-05-01

    Mitochondrial respiratory chain disorders are relatively common inborn errors of energy metabolism, with a combined prevalence of one in 5000. These disorders typically affect tissues with high energy requirements, and cerebral involvement occurs frequently in childhood, often manifesting in seizures. Mitochondrial diseases are genetically heterogeneous; to date, mutations have been reported in all 37 mitochondrially encoded genes and more than 80 nuclear genes. The major genetic causes of mitochondrial epilepsy are mitochondrial DNA mutations (including those typically associated with the mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes [MELAS] and myoclonic epilepsy with ragged red fibres [MERRF] syndromes); mutations in POLG (classically associated with Alpers syndrome but also presenting as the mitochondrial recessive ataxia syndrome [MIRAS], spinocerebellar ataxia with epilepsy [SCAE], and myoclonus, epilepsy, myopathy, sensory ataxia [MEMSA] syndromes in older individuals) and other disorders of mitochondrial DNA maintenance; complex I deficiency; disorders of coenzyme Q(10) biosynthesis; and disorders of mitochondrial translation such as RARS2 mutations. It is not clear why some genetic defects, but not others, are particularly associated with seizures. Epilepsy may be the presenting feature of mitochondrial disease but is often part of a multisystem clinical presentation. Mitochondrial epilepsy may be very difficult to manage, and is often a poor prognostic feature. At present there are no curative treatments for mitochondrial disease. Individuals with mitochondrial epilepsy are frequently prescribed multiple anticonvulsants, and the role of vitamins and other nutritional supplements and the ketogenic diet remain unproven. © The Author. Developmental Medicine & Child Neurology © 2012 Mac Keith Press.

  9. A novel diagnostic tool reveals mitochondrial pathology in human diseases and aging.

    Science.gov (United States)

    Scheibye-Knudsen, Morten; Scheibye-Alsing, Karsten; Canugovi, Chandrika; Croteau, Deborah L; Bohr, Vilhelm A

    2013-03-01

    The inherent complex and pleiotropic phenotype of mitochondrial diseases poses a significant diagnostic challenge for clinicians as well as an analytical barrier for scientists. To overcome these obstacles we compiled a novel database, www.mitodb.com, containing the clinical features of primary mitochondrial diseases. Based on this we developed a number of qualitative and quantitative measures, enabling us to determine whether a disorder can be characterized as mitochondrial. These included a clustering algorithm, a disease network, a mitochondrial barcode and two scoring algorithms. Using these tools we detected mitochondrial involvement in a number of diseases not previously recorded as mitochondrial. As a proof of principle Cockayne syndrome, ataxia with oculomotor apraxia 1 (AOA1), spinocerebellar ataxia with axonal neuropathy 1 (SCAN1) and ataxia-telangiectasia have recently been shown to have mitochondrial dysfunction and those diseases showed strong association with mitochondrial disorders. We next evaluated mitochondrial involvement in aging and detected two distinct categories of accelerated aging disorders, one of them being associated with mitochondrial dysfunction. Normal aging seemed to associate stronger with the mitochondrial diseases than the non-mitochondrial partially supporting a mitochondrial theory of aging.

  10. United Mitochondrial Disease Foundation

    Science.gov (United States)

    ... Grants Funded Projects Patient Evaluation for Professionals Energy Metabolism Review Mitochondrial Structure, Function and Diseases Review Cell ... for Life Walkathons Schedule of EFL Walks UMDF Social Media Tweets by UMDF Our Partners Affiliate Organizations ...

  11. Ocular manifestations of mitochondrial disease

    Directory of Open Access Journals (Sweden)

    S. D. Mathebula

    2012-12-01

    Full Text Available Mitochondrial disease caused by mutations in mitochondrial DNA is recognized as one of the most common causes of inherited neurological disease. Neuro-ophthalmic manifestations are a common feature of mitochondrial disease.  Optic atrophy causing central visual loss is the dominant feature of mitochondrial DNA diseases. Nystagmus is also encountered in mitochondrial disease.Although optometrists are not involved with the management of mitochondrial disease, they are likely to see more patients with this disease. Oph-thalmic examination forms part of the clinical assessment of mitochondrial disease. Mitochondrial disease should be suspected in any patient with unexplained optic neuropathy, ophthalmoplegia, pigmentary retinopathy or retrochiasmal visual loss. Despite considerable advances in the under-standing of mitochondrial genetics and the patho-genesis of mtDNA diseases, no effective treatment options are currently available for patients withmitochondrial dysfunction. (S Afr Optom 201271(1 46-50

  12. Structural analysis of mitochondrial mutations reveals a role for bigenomic protein interactions in human disease.

    Directory of Open Access Journals (Sweden)

    Rhiannon E Lloyd

    Full Text Available Mitochondria are the energy producing organelles of the cell, and mutations within their genome can cause numerous and often severe human diseases. At the heart of every mitochondrion is a set of five large multi-protein machines collectively known as the mitochondrial respiratory chain (MRC. This cellular machinery is central to several processes important for maintaining homeostasis within cells, including the production of ATP. The MRC is unique due to the bigenomic origin of its interacting proteins, which are encoded in the nucleus and mitochondria. It is this, in combination with the sheer number of protein-protein interactions that occur both within and between the MRC complexes, which makes the prediction of function and pathological outcome from primary sequence mutation data extremely challenging. Here we demonstrate how 3D structural analysis can be employed to predict the functional importance of mutations in mtDNA protein-coding genes. We mined the MITOMAP database and, utilizing the latest structural data, classified mutation sites based on their location within the MRC complexes III and IV. Using this approach, four structural classes of mutation were identified, including one underexplored class that interferes with nuclear-mitochondrial protein interactions. We demonstrate that this class currently eludes existing predictive approaches that do not take into account the quaternary structural organization inherent within and between the MRC complexes. The systematic and detailed structural analysis of disease-associated mutations in the mitochondrial Complex III and IV genes significantly enhances the predictive power of existing approaches and our understanding of how such mutations contribute to various pathologies. Given the general lack of any successful therapeutic approaches for disorders of the MRC, these findings may inform the development of new diagnostic and prognostic biomarkers, as well as new drugs and targets for

  13. Human extraocular muscles in mitochondrial diseases: comparing chronic progressive external ophthalmoplegia with Leber's hereditary optic neuropathy.

    Science.gov (United States)

    Carta, A; Carelli, V; D'Adda, T; Ross-Cisneros, F N; Sadun, A A

    2005-07-01

    To compare the ultrastructural aspects of human extraocular muscles in two types of mitochondrial disease: chronic progressive external ophthalmoplegia (CPEO) and Leber's hereditary optic neuropathy (LHON). Muscle samples of the medial rectus obtained from surgery in a sporadic case of CPEO associated with deleted mitochondrial DNA, and post mortem in a case of 3460/ND1 LHON were processed for electron microscopy (EM). The medial rectus from an autoptic time to fixation matched control was used to exclude postmortem artefacts. The CPEO specimen revealed focal areas of disruption and abnormalities of mitochondria in some muscle fibres, creating a "mosaic-like" pattern. In the LHON specimen a diffuse increase in both number and size of mitochondria (mean diameter 0.85 mum v 0.65 mum of control, pCPEO and LHON reveals marked differences. A "mosaic-like" pattern caused by a selective damage of muscle fibres was evident in CPEO, whereas a diffuse increase in mitochondria with preservation of myofibrils characterised the LHON case. These ultrastructural changes may relate to the different expression of the two diseases, resulting in ophthalmoplegia in CPEO and normal eye movements in LHON.

  14. Mitochondrial diseases: a review

    Directory of Open Access Journals (Sweden)

    Daniel Jarovsky

    2006-12-01

    Full Text Available Mitochondria are organelles responsible for production of mostenergy through oxidative phosphorylation process (OXPHOS. Itcontains a double strand DNA (mitDNA of about 16,500 bp encodingtwo ribosomal RNAs and 37 mitochondrial proteins. Mutation inmitDNA may result in multisystem syndromes known asmitochondrial diseases, affecting predominantly tissues thatrequire high levels of ATP such as skeletal muscle (mitochondrialmyopathies, brain (e.g. MELAS, MERRF, LHON e NARP, liver,kidney (Fanconi syndrome, heart and endocrine glands (Pearsonsyndrome. A case of mitochondrial disease was first reported in1962 and correlation of such disease with mutations in mitDNAgained scientific importance in late 1980’s. There are 150 alterationsreported in mitDNA capable of producing metabolic dysfunctionsof clinical relevance. To date, no standard protocol for diagnosis ofmitochondrial diseases has been established, partially due to thewide amplitude of clinical manifestation generally observed. Acombined analysis of clinical data, biochemical, morphologicaland laboratory tests must be performed to evaluate mitochondrialrespiratory chain activity and integrity of nuclear and mitochondrialgenomes. Currently, there are no effective treatments availablefor mitochondrial diseases, but only palliative therapeutics usingconventional strategies to relieve symptoms. Thus, gene therapyemerges as potential therapeutic strategy for more efficienttreatment of mitochondrial diseases.

  15. Nuclear-encoded factors involved in post-transcriptional processing and modification of mitochondrial tRNAs in human disease

    Directory of Open Access Journals (Sweden)

    Christopher A Powell

    2015-03-01

    Full Text Available The human mitochondrial genome (mtDNA encodes twenty-two tRNAs (mt-tRNAs that are necessary for the intraorganellar translation of the thirteen mtDNA-encoded subunits of the mitochondrial respiratory chain complexes. Maturation of mt-tRNAs involves 5’ and 3’ nucleolytic excision from precursor RNAs, as well as extensive post-transcriptional modifications. Recent data suggest that over 7 % of all mt-tRNA residues in mammals undergo post-transcriptional modification, with over 30 different modified mt-tRNA positions so far described. These processing and modification steps are necessary for proper mt-tRNA function, and are performed by dedicated, nuclear-encoded enzymes. Recent growing evidence suggests that mutations in these nuclear genes, leading to incorrect maturation of mt-tRNAs, are a cause of human mitochondrial disease. Furthermore, mtDNA mutations in mt-tRNA genes, which may also affect mt-tRNA function, processing and modification, are also frequently associated with human disease. In theory, all pathogenic mt-tRNA variants should be expected to affect only a single process, which is mitochondrial translation, albeit to various extents. However, the clinical manifestations of mitochondrial disorders linked to mutations in mt-tRNAs are extremely heterogeneous, ranging from defects of a single tissue to complex multisystem disorders. This review focuses on the current knowledge of nuclear genes coding for proteins involved in mt-tRNA maturation that have been linked to human mitochondrial pathologies. We further discuss the possibility that tissue specific regulation of mt-tRNA modifying enzymes could play an important role in the clinical heterogeneity observed for mitochondrial diseases caused by mutations in mt-tRNA genes.

  16. Mitochondrial DNA density homeostasis accounts for a threshold effect in a cybrid model of a human mitochondrial disease.

    Science.gov (United States)

    Aryaman, Juvid; Johnston, Iain G; Jones, Nick S

    2017-11-24

    Mitochondrial dysfunction is involved in a wide array of devastating diseases, but the heterogeneity and complexity of the symptoms of these diseases challenges theoretical understanding of their causation. With the explosion of omics data, we have the unprecedented opportunity to gain deep understanding of the biochemical mechanisms of mitochondrial dysfunction. This goal raises the outstanding need to make these complex datasets interpretable. Quantitative modelling allows us to translate such datasets into intuition and suggest rational biomedical treatments. Taking an interdisciplinary approach, we use a recently published large-scale dataset and develop a descriptive and predictive mathematical model of progressive increase in mutant load of the MELAS 3243A>G mtDNA mutation. The experimentally observed behaviour is surprisingly rich, but we find that our simple, biophysically motivated model intuitively accounts for this heterogeneity and yields a wealth of biological predictions. Our findings suggest that cells attempt to maintain wild-type mtDNA density through cell volume reduction, and thus power demand reduction, until a minimum cell volume is reached. Thereafter, cells toggle from demand reduction to supply increase, up-regulating energy production pathways. Our analysis provides further evidence for the physiological significance of mtDNA density and emphasizes the need for performing single-cell volume measurements jointly with mtDNA quantification. We propose novel experiments to verify the hypotheses made here to further develop our understanding of the threshold effect and connect with rational choices for mtDNA disease therapies. © 2017 The Author(s).

  17. Mitochondrial Diseases: Clinical Features- Management of Patients

    Directory of Open Access Journals (Sweden)

    Filiz Koc

    2003-02-01

    Full Text Available Mitochondria are unique organells which their own DNA in cells. Human mitochondrial DNA is circular, double-stranded molecule and small. Because all mitochondria are contributed by the ovum during the formation of the zygote, the mitochondrial genom is transmitted by maternal inheritance. Multisystem disorders such as deafness, cardiomyopathy, miyopathy can be seen in mitochondrial diseases. [Archives Medical Review Journal 2003; 12(0.100: 14-31

  18. Mitochondrial DNA mutations in Parkinson's disease brain

    National Research Council Canada - National Science Library

    David K Simon; Joanne Clark Matott; Janaina Espinosa; Neeta A Abraham

    2017-01-01

    Dear Editors, We read with interest the publication by Wei et al., Mitochondrial DNA Point Mutations and Relative Copy Number in 1363 Disease and Control Human Brains, Acta Neuropathol Commun. 2017; 5: 13 [4...

  19. Comparison of mitochondrial mutation spectra in ageing human colonic epithelium and disease: absence of evidence for purifying selection in somatic mitochondrial DNA point mutations.

    Directory of Open Access Journals (Sweden)

    Laura C Greaves

    Full Text Available Human ageing has been predicted to be caused by the accumulation of molecular damage in cells and tissues. Somatic mitochondrial DNA (mtDNA mutations have been documented in a number of ageing tissues and have been shown to be associated with cellular mitochondrial dysfunction. It is unknown whether there are selective constraints, which have been shown to occur in the germline, on the occurrence and expansion of these mtDNA mutations within individual somatic cells. Here we compared the pattern and spectrum of mutations observed in ageing human colon to those observed in the general population (germline variants and those associated with primary mtDNA disease. The pathogenicity of the protein encoding mutations was predicted using a computational programme, MutPred, and the scores obtained for the three groups compared. We show that the mutations associated with ageing are randomly distributed throughout the genome, are more frequently non-synonymous or frameshift mutations than the general population, and are significantly more pathogenic than population variants. Mutations associated with primary mtDNA disease were significantly more pathogenic than ageing or population mutations. These data provide little evidence for any selective constraints on the occurrence and expansion of mtDNA mutations in somatic cells of the human colon during human ageing in contrast to germline mutations seen in the general population.

  20. Comparison of mitochondrial mutation spectra in ageing human colonic epithelium and disease: absence of evidence for purifying selection in somatic mitochondrial DNA point mutations.

    Science.gov (United States)

    Greaves, Laura C; Elson, Joanna L; Nooteboom, Marco; Grady, John P; Taylor, Geoffrey A; Taylor, Robert W; Mathers, John C; Kirkwood, Thomas B L; Turnbull, Doug M

    2012-01-01

    Human ageing has been predicted to be caused by the accumulation of molecular damage in cells and tissues. Somatic mitochondrial DNA (mtDNA) mutations have been documented in a number of ageing tissues and have been shown to be associated with cellular mitochondrial dysfunction. It is unknown whether there are selective constraints, which have been shown to occur in the germline, on the occurrence and expansion of these mtDNA mutations within individual somatic cells. Here we compared the pattern and spectrum of mutations observed in ageing human colon to those observed in the general population (germline variants) and those associated with primary mtDNA disease. The pathogenicity of the protein encoding mutations was predicted using a computational programme, MutPred, and the scores obtained for the three groups compared. We show that the mutations associated with ageing are randomly distributed throughout the genome, are more frequently non-synonymous or frameshift mutations than the general population, and are significantly more pathogenic than population variants. Mutations associated with primary mtDNA disease were significantly more pathogenic than ageing or population mutations. These data provide little evidence for any selective constraints on the occurrence and expansion of mtDNA mutations in somatic cells of the human colon during human ageing in contrast to germline mutations seen in the general population.

  1. DNA Sequences Proximal to Human Mitochondrial DNA Deletion Breakpoints Prevalent in Human Disease Form G-quadruplexes, a Class of DNA Structures Inefficiently Unwound by the Mitochondrial Replicative Twinkle Helicase

    NARCIS (Netherlands)

    Bharti, S.K.; Sommers, J.A.; Zhou, J.; Kaplan, D.L.; Spelbrink, J.N.; Mergny, J.L.; Brosh, R.M., Jr.

    2014-01-01

    Mitochondrial DNA deletions are prominent in human genetic disorders, cancer, and aging. It is thought that stalling of the mitochondrial replication machinery during DNA synthesis is a prominent source of mitochondrial genome instability; however, the precise molecular determinants of defective

  2. Recent Advances in Mitochondrial Disease.

    Science.gov (United States)

    Craven, Lyndsey; Alston, Charlotte L; Taylor, Robert W; Turnbull, Doug M

    2017-08-31

    Mitochondrial disease is a challenging area of genetics because two distinct genomes can contribute to disease pathogenesis. It is also challenging clinically because of the myriad of different symptoms and, until recently, a lack of a genetic diagnosis in many patients. The last five years has brought remarkable progress in this area. We provide a brief overview of mitochondrial origin, function, and biology, which are key to understanding the genetic basis of mitochondrial disease. However, the primary purpose of this review is to describe the recent advances related to the diagnosis, genetic basis, and prevention of mitochondrial disease, highlighting the newly described disease genes and the evolving methodologies aimed at preventing mitochondrial DNA disease transmission.

  3. A plasma signature of human mitochondrial disease revealed through metabolic profiling of spent media from cultured muscle cells.

    Science.gov (United States)

    Shaham, Oded; Slate, Nancy G; Goldberger, Olga; Xu, Qiuwei; Ramanathan, Arvind; Souza, Amanda L; Clish, Clary B; Sims, Katherine B; Mootha, Vamsi K

    2010-01-26

    Mutations in either the mitochondrial or nuclear genomes can give rise to respiratory chain disease (RCD), a large class of devastating metabolic disorders. Their clinical management is challenging, in part because we lack facile and accurate biomarkers to aid in diagnosis and in the monitoring of disease progression. Here we introduce a sequential strategy that combines biochemical analysis of spent media from cell culture with analysis of patient plasma to identify disease biomarkers. First, we applied global metabolic profiling to spotlight 32 metabolites whose uptake or secretion kinetics were altered by chemical inhibition of the respiratory chain in cultured muscle . These metabolites span a wide range of pathways and include lactate and alanine, which are used clinically as biomarkers of RCD. We next measured the cell culture-defined metabolites in human plasma to discover that creatine is reproducibly elevated in two independent cohorts of RCD patients, exceeding lactate and alanine in magnitude of elevation and statistical significance. In cell culture extracellular creatine was inversely related to the intracellular phosphocreatine:creatine ratio suggesting that the elevation of plasma creatine in RCD patients signals a low energetic state of tissues using the phosphocreatine shuttle. Our study identifies plasma creatine as a potential biomarker of human mitochondrial dysfunction that could be clinically useful. More generally, we illustrate how spent media from cellular models of disease may provide a window into the biochemical derangements in human plasma, an approach that could, in principle, be extended to a range of complex diseases.

  4. Comparison of mitochondrial mutation spectra in ageing human colonic epithelium and disease: absence of evidence for purifying selection in somatic mitochondrial DNA point mutations

    NARCIS (Netherlands)

    Greaves, L.C.; Elson, J.L.; Nooteboom, M.; Grady, J.P.; Taylor, G.A.; Taylor, R.W.; Mathers, J.C.; Kirkwood, T.B.; Turnbull, D.M.

    2012-01-01

    Human ageing has been predicted to be caused by the accumulation of molecular damage in cells and tissues. Somatic mitochondrial DNA (mtDNA) mutations have been documented in a number of ageing tissues and have been shown to be associated with cellular mitochondrial dysfunction. It is unknown

  5. Hypoxia as a therapy for mitochondrial disease.

    Science.gov (United States)

    Jain, Isha H; Zazzeron, Luca; Goli, Rahul; Alexa, Kristen; Schatzman-Bone, Stephanie; Dhillon, Harveen; Goldberger, Olga; Peng, Jun; Shalem, Ophir; Sanjana, Neville E; Zhang, Feng; Goessling, Wolfram; Zapol, Warren M; Mootha, Vamsi K

    2016-04-01

    Defects in the mitochondrial respiratory chain (RC) underlie a spectrum of human conditions, ranging from devastating inborn errors of metabolism to aging. We performed a genome-wide Cas9-mediated screen to identify factors that are protective during RC inhibition. Our results highlight the hypoxia response, an endogenous program evolved to adapt to limited oxygen availability. Genetic or small-molecule activation of the hypoxia response is protective against mitochondrial toxicity in cultured cells and zebrafish models. Chronic hypoxia leads to a marked improvement in survival, body weight, body temperature, behavior, neuropathology, and disease biomarkers in a genetic mouse model of Leigh syndrome, the most common pediatric manifestation of mitochondrial disease. Further preclinical studies are required to assess whether hypoxic exposure can be developed into a safe and effective treatment for human diseases associated with mitochondrial dysfunction. Copyright © 2016, American Association for the Advancement of Science.

  6. Mitochondrial dynamics in mammalian health and disease.

    Science.gov (United States)

    Liesa, Marc; Palacín, Manuel; Zorzano, Antonio

    2009-07-01

    The meaning of the word mitochondrion (from the Greek mitos, meaning thread, and chondros, grain) illustrates that the heterogeneity of mitochondrial morphology has been known since the first descriptions of this organelle. Such a heterogeneous morphology is explained by the dynamic nature of mitochondria. Mitochondrial dynamics is a concept that includes the movement of mitochondria along the cytoskeleton, the regulation of mitochondrial architecture (morphology and distribution), and connectivity mediated by tethering and fusion/fission events. The relevance of these events in mitochondrial and cell physiology has been partially unraveled after the identification of the genes responsible for mitochondrial fusion and fission. Furthermore, during the last decade, it has been identified that mutations in two mitochondrial fusion genes (MFN2 and OPA1) cause prevalent neurodegenerative diseases (Charcot-Marie Tooth type 2A and Kjer disease/autosomal dominant optic atrophy). In addition, other diseases such as type 2 diabetes or vascular proliferative disorders show impaired MFN2 expression. Altogether, these findings have established mitochondrial dynamics as a consolidated area in cellular physiology. Here we review the most significant findings in the field of mitochondrial dynamics in mammalian cells and their implication in human pathologies.

  7. Epigenetics, epidemiology and mitochondrial DNA diseases

    OpenAIRE

    Chinnery, Patrick F; Elliott, Hannah R; Hudson, Gavin; Samuels, David C; Relton, Caroline L

    2012-01-01

    Over the last two decades, the mutation of mitochondrial DNA (mtDNA) has emerged as a major cause of inherited human disease. The disorders present clinically in at least 1 in 10 000 adults, but pathogenic mutations are found in approximately 1 in 200 of the background population. Mitochondrial DNA is maternally inherited and there can be marked phenotypic variability within the same family. Heteroplasmy is a significant factor and environmental toxins also appear to modulate the phenotype. A...

  8. Mitochondrial Dysfunction in Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    P. C. Keane

    2011-01-01

    Full Text Available Parkinson's disease (PD is a progressive, neurodegenerative condition that has increasingly been linked with mitochondrial dysfunction and inhibition of the electron transport chain. This inhibition leads to the generation of reactive oxygen species and depletion of cellular energy levels, which can consequently cause cellular damage and death mediated by oxidative stress and excitotoxicity. A number of genes that have been shown to have links with inherited forms of PD encode mitochondrial proteins or proteins implicated in mitochondrial dysfunction, supporting the central involvement of mitochondria in PD. This involvement is corroborated by reports that environmental toxins that inhibit the mitochondrial respiratory chain have been shown to be associated with PD. This paper aims to illustrate the considerable body of evidence linking mitochondrial dysfunction with neuronal cell death in the substantia nigra pars compacta (SNpc of PD patients and to highlight the important need for further research in this area.

  9. Movement disorders in mitochondrial disease.

    Science.gov (United States)

    Ghaoui, Roula; Sue, Carolyn M

    2018-01-06

    Mitochondrial disease presents with a wide spectrum of clinical manifestations that may appear at any age and cause multisystem dysfunction. A broad spectrum of movement disorders can manifest in mitochondrial diseases including ataxia, Parkinsonism, myoclonus, dystonia, choreoathetosis, spasticity, tremor, tic disorders and restless legs syndrome. There is marked heterogeneity of movement disorder phenotypes, even in patients with the same genetic mutation. Moreover, the advent of new technologies, such as next-generation sequencing, is likely to identify novel causative genes, expand the phenotype of known disease genes and improve the genetic diagnosis in these patients. Identification of the underlying genetic basis of the movement disorder is also a crucial step to allow for targeted therapies to be implemented as well as provide the basis for a better understanding of the molecular pathophysiology of the disease process. The aim of this review is to discuss the spectrum of movement disorders associated with mitochondrial disease.

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    It has been suggested that human mitochondrial variants influence maximal oxygen uptake (VO2max). Whether mitochondrial respiratory capacity per mitochondrion (intrinsic activity) in human skeletal muscle is affected by differences in mitochondrial variants is not known. We recruited 54 males...

  11. Human extraocular muscles in mitochondrial diseases: comparing chronic progressive external ophthalmoplegia with Leber’s hereditary optic neuropathy

    Science.gov (United States)

    Carta, A; Carelli, V; D’Adda, T; Ross-Cisneros, F N; Sadun, A A

    2005-01-01

    Aims: To compare the ultrastructural aspects of human extraocular muscles in two types of mitochondrial disease: chronic progressive external ophthalmoplegia (CPEO) and Leber’s hereditary optic neuropathy (LHON). Methods: Muscle samples of the medial rectus obtained from surgery in a sporadic case of CPEO associated with deleted mitochondrial DNA, and post mortem in a case of 3460/ND1 LHON were processed for electron microscopy (EM). The medial rectus from an autoptic time to fixation matched control was used to exclude postmortem artefacts. Results: The CPEO specimen revealed focal areas of disruption and abnormalities of mitochondria in some muscle fibres, creating a “mosaic-like” pattern. In the LHON specimen a diffuse increase in both number and size of mitochondria (mean diameter 0.85 μm v 0.65 μm of control, pCPEO and LHON reveals marked differences. A “mosaic-like” pattern caused by a selective damage of muscle fibres was evident in CPEO, whereas a diffuse increase in mitochondria with preservation of myofibrils characterised the LHON case. These ultrastructural changes may relate to the different expression of the two diseases, resulting in ophthalmoplegia in CPEO and normal eye movements in LHON. PMID:15965159

  12. Autism Spectrum Disorder and Mitochondrial Disease

    Science.gov (United States)

    ... Is there a relationship between mitochondrial disease and autism? A: A child with a mitochondrial disease: may ... something else. Q: Is there a relationship between autism and encephalopathy? A: Most children with an autism ...

  13. Iron and Copper in Mitochondrial Diseases

    Science.gov (United States)

    Xu, Wenjing; Barrientos, Tomasa; Andrews, Nancy C.

    2013-01-01

    Summary Transition metals are frequently used as co-factors for enzymes and oxygen-carrying proteins that take advantage of their propensity to gain and lose single electrons. Metals are particularly important in mitochondria, where they play essential roles in the production of ATP and detoxification of reactive oxygen species. At the same time, transition metals (particularly Fe and Cu) can promote the formation of harmful radicals, necessitating meticulous control of metal concentration and subcellular compartmentalization. We summarize our current understanding of Fe and Cu in mammalian mitochondrial biology, and discuss human diseases associated with aberrations in mitochondrial metal homeostasis. PMID:23473029

  14. Mutations in human DNA polymerase γ confer unique mechanisms of catalytic deficiency that mirror the disease severity in mitochondrial disorder patients

    Science.gov (United States)

    Sohl, Christal D.; Kasiviswanathan, Rajesh; Copeland, William C.; Anderson, Karen S.

    2013-01-01

    Human mitochondrial DNA polymerase γ (pol γ) is solely responsible for the replication and repair of the mitochondrial genome. Unsurprisingly, alterations in pol γ activity have been associated with mitochondrial diseases such as Alpers syndrome and progressive external ophthalmoplegia. Thus far, predicting the severity of mitochondrial disease based the magnitude of deficiency in pol γ activity has been difficult. In order to understand the relationship between disease severity in patients and enzymatic defects in vitro, we characterized the molecular mechanisms of four pol γ mutations, A957P, A957S, R1096C and R1096H, which have been found in patients suffering from aggressive Alpers syndrome to mild progressive external ophthalmoplegia. The A957P mutant showed the most striking deficiencies in the incorporation efficiency of a correct deoxyribonucleotide triphosphate (dNTP) relative to wild-type pol γ, with less, but still significant incorporation efficiency defects seen in R1096H and R1096C, and only a small decrease in incorporation efficiency observed for A957S. Importantly, this trend matches the disease severity observed in patients very well (approximated as , from most severe disease to least severe). Further, the A957P mutation conferred a two orders of magnitude loss of fidelity relative to wild-type pol γ, indicating that a buildup of mitochondrial genomic mutations may contribute to the death in infancy seen with these patients. We conclude that characterizing the unique molecular mechanisms of pol γ deficiency for physiologically important mutant enzymes is important for understanding mitochondrial disease and for predicting disease severity. PMID:23208208

  15. Synaptic Mitochondrial Pathology in Alzheimer's Disease

    Science.gov (United States)

    Du, Heng; Guo, Lan

    2012-01-01

    Abstract Significance: Synaptic degeneration, an early pathological feature in Alzheimer's disease (AD), is closely correlated to impaired cognitive function and memory loss. Recent studies suggest that involvement of amyloid-beta peptide (Aβ) in synaptic mitochondrial alteration underlies these synaptic lesions. Thus, to understand the Aβ-associated synaptic mitochondrial perturbations would fortify our understanding of synaptic stress in the pathogenesis of AD. Recent Advances: Increasing evidence suggests that synaptic mitochondrial dysfunction is strongly associated with synaptic failure in many neurodegenerative diseases including AD. Based on recent findings in human AD subjects, AD animal models, and AD cellular models, synaptic mitochondria undergo multiple malfunctions including Aβ accumulation, increased oxidative stress, decreased respiration, and compromised calcium handling capacity, all of which occur earlier than changes seen in nonsynaptic mitochondria before predominant AD pathology. Of note, the impact of Aβ on mitochondrial motility and dynamics exacerbates synaptic mitochondrial alterations. Critical Issues: Synaptic mitochondria demonstrate early deficits in AD; in combination with the role that synaptic mitochondria play in sustaining synaptic functions, deficits in synaptic mitochondria may be a key factor involved in an early synaptic pathology in AD. Future Directions: The importance of synaptic mitochondria in supporting synapses and the high vulnerability of synaptic mitochondria to Aβ make them a promising target of new therapeutic strategy for AD. Antioxid. Redox Signal. 16, 1467–1475. PMID:21942330

  16. What Is Mitochondrial Disease?

    Science.gov (United States)

    ... Abuse Adult Advisory Council Team (AACT) Resources for Kids & Teens Find a Doctor Find a Doctor Genetic Testing ... Links to Other Diseases Treatments & Therapies Resources for Kids & Teens Frequently Asked Questions Introductory Videos Contact Us 8085 ...

  17. Towards a functional definition of the mitochondrial human proteome

    Directory of Open Access Journals (Sweden)

    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.

  18. Clinical manifestation of mitochondrial diseases.

    Science.gov (United States)

    Magner, Martin; Kolářová, Hana; Honzik, Tomáš; Švandová, Ivana; Zeman, Jiří

    2015-01-01

    Mitochondrial disorders (MD) represent a clinically, biochemically and genetically heterogeneous group of diseases associated with dysfunction of the oxidative phosphorylation system and pyruvate dehydrogenase complex. Our aim was to illustrate the most common clinical presentation of MD on the example of selected diseases and syndromes. The minimal prevalence of MD is estimated as 1 to 5,000. MD may manifest at any age since birth until late-adulthood with acute manifestation or as a chronic progressive disease. Virtually any organ may be impaired, but the organs with the highest energetic demands are most frequently involved, including brain, muscle, heart and liver. Some MD may manifest as a characteristic cluster of clinical features (e.g. MELAS syndrome, Kearns-Sayre syndrome). Diagnostics includes detailed history, the comprehensive clinical examination, results of specialized examinations (especially cardiology, visual fundus examination, brain imaging, EMG), laboratory testing of body fluids (lactate, aminoacids, organic acids), and analysis of bioptic samples of muscle, skin, and liver, eventually. Normal lactate level in blood does not exclude the possibility of MD. Although the aimed molecular genetic analyses may be indicated in some of mitochondrial diseases, the methods of next generation sequencing come into focus. Examples of treatment are arginine supplementation in MELAS syndrome, ketogenic diet in pyruvate oxidation disorders or quinone analogs in patients with LHON. Conclusion: The clinical suspicion of a mitochondrial disorder is often delayed, or the disease remains undiagnosed. The correct diagnosis and adequate treatment can improve prognosis of the patient. Access to genetic counseling is also of great importance.

  19. Preventing Mitochondrial Disease: A Path Forward.

    Science.gov (United States)

    Adashi, Eli Y; Cohen, I Glenn

    2018-03-01

    In a possible first, the heritable transmission of a fatal mitochondrial DNA disease (Leigh syndrome) may have been prevented by replacing the mutation-bearing mitochondria of oocytes with donated mutation-free counterparts. The procedure, carried out by a U.S.-led team, took place in Mexico in circumvention of a statutory U.S. moratorium on mitochondrial replacement. This development calls into question the regulatory utility of a national moratorium in a globalized world wherein cross-border care is increasingly prevalent. This development also calls to account the moral defensibility of a moratorium that acquiesces in the birth of gravely ill children whose afflictions could have been prevented. In this Current Commentary, we outline a potential path forward by analyzing the dual imprint of the moratorium, examining its legislative shortcomings, exploring its motivational roots, considering its national effect, and proposing its unlinking from the related yet distinct ban on editing the genome of the human embryo.

  20. Mitochondrial and Cell Death Mechanisms in Neurodegenerative Diseases

    Directory of Open Access Journals (Sweden)

    Lee J. Martin

    2010-03-01

    Full Text Available Alzheimer’s disease (AD, Parkinson’s disease (PD and amyotrophic lateral sclerosis (ALS are the most common human adult-onset neurodegenerative diseases. They are characterized by prominent age-related neurodegeneration in selectively vulnerable neural systems. Some forms of AD, PD, and ALS are inherited, and genes causing these diseases have been identified. Nevertheless, the mechanisms of the neuronal cell death are unresolved. Morphological, biochemical, genetic, as well as cell and animal model studies reveal that mitochondria could have roles in this neurodegeneration. The functions and properties of mitochondria might render subsets of selectively vulnerable neurons intrinsically susceptible to cellular aging and stress and overlying genetic variations, triggering neurodegeneration according to a cell death matrix theory. In AD, alterations in enzymes involved in oxidative phosphorylation, oxidative damage, and mitochondrial binding of Aβ and amyloid precursor protein have been reported. In PD, mutations in putative mitochondrial proteins have been identified and mitochondrial DNA mutations have been found in neurons in the substantia nigra. In ALS, changes occur in mitochondrial respiratory chain enzymes and mitochondrial cell death proteins. Transgenic mouse models of human neurodegenerative disease are beginning to reveal possible principles governing the biology of selective neuronal vulnerability that implicate mitochondria and the mitochondrial permeability transition pore. This review summarizes how mitochondrial pathobiology might contribute to neuronal death in AD, PD, and ALS and could serve as a target for drug therapy.

  1. MiSynPat: An integrated knowledge base linking clinical, genetic, and structural data for disease-causing mutations in human mitochondrial aminoacyl-tRNA synthetases.

    Science.gov (United States)

    Moulinier, Luc; Ripp, Raymond; Castillo, Gaston; Poch, Olivier; Sissler, Marie

    2017-10-01

    Numerous mutations in each of the mitochondrial aminoacyl-tRNA synthetases (aaRSs) have been implicated in human diseases. The mutations are autosomal and recessive and lead mainly to neurological disorders, although with pleiotropic effects. The processes and interactions that drive the etiology of the disorders associated with mitochondrial aaRSs (mt-aaRSs) are far from understood. The complexity of the clinical, genetic, and structural data requires concerted, interdisciplinary efforts to understand the molecular biology of these disorders. Toward this goal, we designed MiSynPat, a comprehensive knowledge base together with an ergonomic Web server designed to organize and access all pertinent information (sequences, multiple sequence alignments, structures, disease descriptions, mutation characteristics, original literature) on the disease-linked human mt-aaRSs. With MiSynPat, a user can also evaluate the impact of a possible mutation on sequence-conservation-structure in order to foster the links between basic and clinical researchers and to facilitate future diagnosis. The proposed integrated view, coupled with research on disease-related mt-aaRSs, will help to reveal new functions for these enzymes and to open new vistas in the molecular biology of the cell. The purpose of MiSynPat, freely available at http://misynpat.org, is to constitute a reference and a converging resource for scientists and clinicians. © 2017 The Authors. Human Mutation published by Wiley Periodicals, Inc.

  2. Role and Treatment of Mitochondrial DNA-Related Mitochondrial Dysfunction in Sporadic Neurodegenerative Diseases

    OpenAIRE

    Swerdlow, Russell H.

    2011-01-01

    Several sporadic neurodegenerative diseases display phenomena that directly or indirectly relate to mitochondrial function. Data suggesting altered mitochondrial function in these diseases could arise from mitochondrial DNA (mtDNA) are reviewed. Approaches for manipulating mitochondrial function and minimizing the downstream consequences of mitochondrial dysfunction are discussed.

  3. Mitochondrial dysfunction underlying outer retinal diseases

    DEFF Research Database (Denmark)

    Lefevere, Evy; Toft-Kehler, Anne Katrine; Vohra, Rupali

    2017-01-01

    Dysfunction of photoreceptors, retinal pigment epithelium (RPE) or both contribute to the initiation and progression of several outer retinal disorders. Disrupted Müller glia function might additionally subsidize to these diseases. Mitochondrial malfunctioning is importantly associated with outer...

  4. Mitochondrial dysfunction and human immunodeficiency virus ...

    African Journals Online (AJOL)

    Human immunodeficiency virus (HIV) infection and the pharmacological treatment thereof have both been shown to affect mitochondrial function in a number of tissues, and each may cause specific organ pathology through specific mitochondrial pathways. HIV has been shown to kill various tissue cells by activation of ...

  5. The Neuro-Ophthalmology of Mitochondrial Disease

    Science.gov (United States)

    Fraser, J. Alexander; Biousse, Valérie; Newman, Nancy J.

    2010-01-01

    Mitochondrial diseases frequently manifest neuro-ophthalmologic symptoms and signs. Because of the predilection of mitochondrial disorders to involve the optic nerves, extraocular muscles, retina, and even the retrochiasmal visual pathways, the ophthalmologist is often the first physician to be consulted. Disorders caused by mitochondrial dysfunction can result from abnormalities in either the mitochondrial DNA or in nuclear genes which encode mitochondrial proteins. Inheritance of these mutations will follow patterns specific to their somatic or mitochondrial genetics. Genotype-phenotype correlations are inconstant, and considerable overlap may occur among these syndromes. The diagnostic approach to the patient with suspected mitochondrial disease entails a detailed personal and family history, careful ophthalmic, neurologic, and systemic examination, directed investigations, and attention to potentially life-threatening sequelae. Although curative treatments for mitochondrial disorders are currently lacking, exciting research advances are being made, particularly in the area of gene therapy. Leber hereditary optic neuropathy, with its window of opportunity for timely intervention and its accessibility to directed therapy, offers a unique model to study future therapeutic interventions. Most patients and their relatives benefit from informed genetic counseling. PMID:20471050

  6. White matter involvement in mitochondrial diseases.

    Science.gov (United States)

    Lerman-Sagie, Tally; Leshinsky-Silver, Esther; Watemberg, Nathan; Luckman, Yehudit; Lev, Dorit

    2005-02-01

    White matter involvement is recently being realized as a common finding in mitochondrial disorders. It is considered an inherent part of the classical mitochondrial syndromes which are usually associated with alterations in the mitochondrial DNA such as: Leigh disease, Kearns-Sayre syndrome, mitochondrial encephalomyopathy lactic acidosis, and stroke like episodes, mitochondrial neuro-gastro-intestinal encephalomyopathy and Leber's hereditary optic neuropathy. White matter involvement is also described in mitochondrial disorders due to mutations in the nuclear DNA which are transmitted in an autosomal pattern. MRI findings suggestive of a mitochondrial disease are: small cyst-like lesions in abnormal white matter, involvement of both cerebral and cerebellar white matter, and a combination of a leukoencephalopathy with bilateral basal ganglia lesions. The clinical manifestations may be disproportionate to the extent of white matter involvement. Other organs may frequently be involved. The onset is often in infancy with a neurodegenerative course. The finding of a leukoencephalopathy in a patient with a complex neurologic picture and multisystem involvement should prompt a thorough mitochondrial evaluation.

  7. Exploring mitochondrial system properties of neurodegenerative diseases through interactome mapping.

    Science.gov (United States)

    Vlasblom, James; Jin, Ke; Kassir, Sandy; Babu, Mohan

    2014-04-04

    Mitochondria are double membraned, dynamic organelles that are required for a large number of cellular processes, and defects in their function have emerged as causative factors for a growing number of human disorders and are highly associated with cancer, metabolic, and neurodegenerative (ND) diseases. Biochemical and genetic investigations have uncovered small numbers of candidate mitochondrial proteins (MPs) involved in ND disease, but given the diversity of processes affected by MP function and the difficulty of detecting interactions involving these proteins, many more likely remain unknown. However, high-throughput proteomic and genomic approaches developed in genetically tractable model prokaryotes and lower eukaryotes have proven to be effective tools for querying the physical (protein-protein) and functional (gene-gene) relationships between diverse types of proteins, including cytosolic and membrane proteins. In this review, we highlight how experimental and computational approaches developed recently by our group and others can be effectively used towards elucidating the mitochondrial interactome in an unbiased and systematic manner to uncover network-based connections. We discuss how the knowledge from the resulting interaction networks can effectively contribute towards the identification of new mitochondrial disease gene candidates, and thus further clarify the role of mitochondrial biology and the complex etiologies of ND disease. Biochemical and genetic investigations have uncovered small numbers of candidate mitochondrial proteins (MPs) involved in neurodegenerative (ND) diseases, but given the diversity of processes affected by MP function and the difficulty of detecting interactions involving these proteins, many more likely remain unknown. Large-scale proteomic and genomic approaches developed in model prokaryotes and lower eukaryotes have proven to be effective tools for querying the physical (protein-protein) and functional (gene

  8. Mitochondrial transcription factor A protects human retinal ...

    African Journals Online (AJOL)

    , and the probable mechanism. Methods: After ... Keywords: Mitochondrial transcription factor A, NF-κB, Hypoxia, Human retinal endothelial cell,. Diabetic retinopathy ..... choice for diabetic retinopathy therapy, as TFAM activity clearly affects the ...

  9. Nonneutral mitochondrial DNA variation in humans and chimpanzees

    Energy Technology Data Exchange (ETDEWEB)

    Nachman, M.W.; Aquadro, C.F. [Cornell Univ., Ithaca, NY (United States); Brown, W.M. [Univ. of Michigan, Ann Arbor, MI (United States)] [and others

    1996-03-01

    We sequenced the NADH dehydrogenase subunit 3 (ND3) gene from a sample of 61 humans, five common chimpanzees, and one gorilla to test whether patterns of mitochondrial DNA (mtDNA) variation are consistent with a neutral model of molecular evolution. Within humans and within chimpanzees, the ratio of replacement to silent nucleotide substitutions was higher than observed in comparisons between species, contrary to neutral expectations. To test the generality of this result, we reanalyzed published human RFLP data from the entire mitochondrial genome. Gains of restriction sites relative to a known human mtDNA sequence were used to infer unambiguous nucleotide substitutions. We also compared the complete mtDNA sequences of three humans. Both the RFLP data and the sequence data reveal a higher ratio of replacement to silent nucleotide substitutions within humans than is seen between species. This pattern is observed at most or all human mitochondrial genes and is inconsistent with a strictly neutral model. These data suggest that many mitochondrial protein polymorphisms are slightly deleterious, consistent with studies of human mitochondrial diseases. 59 refs., 2 figs., 8 tabs.

  10. Mitochondrial alterations in children with chronic liver disease

    African Journals Online (AJOL)

    Rabah M. Shawky

    mitochondrial DNA) have been identified, with the promise of genetic and prenatal diagnosis [5]. Studies assessing mito- chondrial function and structure in livers from humans with chronic liver disease, including liver cirrhosis, revealed a variety of alterations in comparison with normal subjects. Depending on the aetiology ...

  11. Concise Review: Heteroplasmic Mitochondrial DNA Mutations and Mitochondrial Diseases: Toward iPSC-Based Disease Modeling, Drug Discovery, and Regenerative Therapeutics.

    Science.gov (United States)

    Hatakeyama, Hideyuki; Goto, Yu-Ichi

    2016-04-01

    Mitochondria contain multiple copies of their own genome (mitochondrial DNA; mtDNA). Once mitochondria are damaged by mutant mtDNA, mitochondrial dysfunction is strongly induced, followed by symptomatic appearance of mitochondrial diseases. Major genetic causes of mitochondrial diseases are defects in mtDNA, and the others are defects of mitochondria-associating genes that are encoded in nuclear DNA (nDNA). Numerous pathogenic mutations responsible for various types of mitochondrial diseases have been identified in mtDNA; however, it remains uncertain why mitochondrial diseases present a wide variety of clinical spectrum even among patients carrying the same mtDNA mutations (e.g., variations in age of onset, in affected tissues and organs, or in disease progression and phenotypic severity). Disease-relevant induced pluripotent stem cells (iPSCs) derived from mitochondrial disease patients have therefore opened new avenues for understanding the definitive genotype-phenotype relationship of affected tissues and organs in various types of mitochondrial diseases triggered by mtDNA mutations. In this concise review, we briefly summarize several recent approaches using patient-derived iPSCs and their derivatives carrying various mtDNA mutations for applications in human mitochondrial disease modeling, drug discovery, and future regenerative therapeutics. © 2016 AlphaMed Press.

  12. Poor man’s 1000 genome project: Recent human population expansion confounds the detection of disease alleles in 7,098 complete mitochondrial genomes

    Directory of Open Access Journals (Sweden)

    Hie Lim eKim

    2013-02-01

    Full Text Available Rapid growth of the human population has caused the accumulation of rare genetic variants that may play a role in the origin of genetic diseases. However, it is challenging to identify those rare variants responsible for specific diseases without genetic data from an extraordinarily large population sample. Here we focused on the accumulated data from the human mitochondrial (mt genome sequences because this data provided 7,098 whole genomes for analysis. In this dataset we identified 6,110 single nucleotide variants (SNVs and their frequency and determined that the best-fit demographic model for the 7,098 genomes included severe population bottlenecks and exponential expansions of the non-African population. Using this model, we simulated the evolution of mt genomes in order to ascertain the behavior of deleterious mutations. We found that such deleterious mutations barely survived during population expansion. We derived the threshold frequency of a deleterious mutation in separate African, Asian, and European populations and used it to identify pathogenic mutations in our dataset. Although threshold frequency was very low, the proportion of variants showing a lower frequency than that threshold was 82%, 83%, and 91% of the total variants for the African, Asian, and European populations, respectively. Within these variants, only 18 known pathogenic mutations were detected in the 7,098 genomes. This result showed the difficulty of detecting a pathogenic mutation within an abundance of rare variants in the human population, even with a large number of genomes available for study.

  13. Disorders of phospholipid metabolism: an emerging class of mitochondrial disease due to defects in nuclear genes

    Directory of Open Access Journals (Sweden)

    Ya-Wen eLu

    2015-02-01

    Full Text Available The human nuclear and mitochondrial genomes co-exist within each cell. While the mitochondrial genome encodes for a limited number of proteins, transfer RNAs, and ribosomal RNAs, the vast majority of mitochondrial proteins are encoded in the nuclear genome. Of the multitude of mitochondrial disorders known to date, only a fifth are maternally inherited. The recent characterization of the mitochondrial proteome therefore serves as an important step towards delineating the nosology of a large spectrum of phenotypically heterogeneous diseases. Following the identification of the first nuclear gene defect to underlie a mitochondrial disorder, a plenitude of genetic variants that provoke mitochondrial pathophysiology have been molecularly elucidated and classified into six categories that impact: 1 oxidative phosphorylation (subunits and assembly factors; 2 mitochondrial DNA maintenance and expression; 3 mitochondrial protein import and assembly; 4 mitochondrial quality control (chaperones and proteases; 5 iron-sulfur cluster homeostasis; and 6 mitochondrial dynamics (fission and fusion. Here, we propose that an additional class of genetic variant be included in the classification schema to acknowledge the role of genetic defects in phospholipid biosynthesis, remodeling, and metabolism in mitochondrial pathophysiology. This seventh class includes a small but notable group of nuclear-encoded proteins whose dysfunction impacts normal mitochondrial phospholipid metabolism. The resulting human disorders present with a diverse array of pathologic consequences that reflect the variety of functions that phospholipids have in mitochondria and highlight the important role of proper membrane homeostasis in mitochondrial biology.

  14. Correlation between mitochondrial dysfunction and the pathogenesis of Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Xiao-yu LIU

    2014-02-01

    Full Text Available Parkinson's disease (PD is a progressive neurodegenerative disease. A growing number of studies have shown that mitochondrial dysfunction plays an important role in the pathogenesis of PD. Therefore, this review will mainly discuss the research progress on the correlation between PD and abnormal mitochondrial dynamics, mitochondrial autophapy as well as mitochondrial DNA mutations and mitochondrial complex Ⅰ inhibition.doi:10.3969/j.issn.1672-6731.2014.02.012

  15. Parkinson's disease and mitochondrial gene variations

    DEFF Research Database (Denmark)

    Andalib, Sasan; Vafaee, Manouchehr Seyedi; Gjedde, Albert

    2014-01-01

    Parkinson's disease (PD) is a common disorder of the central nervous system in the elderly. The pathogenesis of PD is a complex process, with genetics as an important contributing factor. This factor may stem from mitochondrial gene variations and mutations as well as from nuclear gene variations...

  16. Mitochondrial signaling in health and disease

    National Research Council Canada - National Science Library

    Orrenius, Sten; Packer, Lester; Cadenas, Enrique

    2012-01-01

    .... The text covers themes essential for the maintenance of mitochondrial activity, including electron transport and energy production, mitochondrial biogenesis and dynamics, mitochondrial signaling...

  17. Altered Mitochondrial DNA Methylation Pattern in Alzheimer Disease-Related Pathology and in Parkinson Disease.

    Science.gov (United States)

    Blanch, Marta; Mosquera, Jose Luis; Ansoleaga, Belén; Ferrer, Isidre; Barrachina, Marta

    2016-02-01

    Mitochondrial dysfunction is linked with the etiopathogenesis of Alzheimer disease and Parkinson disease. Mitochondria are intracellular organelles essential for cell viability and are characterized by the presence of the mitochondrial (mt)DNA. DNA methylation is a well-known epigenetic mechanism that regulates nuclear gene transcription. However, mtDNA methylation is not the subject of the same research attention. The present study shows the presence of mitochondrial 5-methylcytosine in CpG and non-CpG sites in the entorhinal cortex and substantia nigra of control human postmortem brains, using the 454 GS FLX Titanium pyrosequencer. Moreover, increased mitochondrial 5-methylcytosine levels are found in the D-loop region of mtDNA in the entorhinal cortex in brain samples with Alzheimer disease-related pathology (stages I to II and stages III to IV of Braak and Braak; n = 8) with respect to control cases. Interestingly, this region shows a dynamic pattern in the content of mitochondrial 5-methylcytosine in amyloid precursor protein/presenilin 1 mice along with Alzheimer disease pathology progression (3, 6, and 12 months of age). Finally, a loss of mitochondrial 5-methylcytosine levels in the D-loop region is found in the substantia nigra in Parkinson disease (n = 10) with respect to control cases. In summary, the present findings suggest mtDNA epigenetic modulation in human brain is vulnerable to neurodegenerative disease states. Copyright © 2016 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  18. 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.......05), and the levels of antioxidant protein expression was lower. Diminished mitochondrial respiration capacity and excessive ROS production demonstrate an impaired mitochondrial function in ischemic human heart muscle. No chronic ischemic preconditioning effect was found......., and finally to assess myocardial antioxidant levels. Mitochondrial respiration in biopsies from ischemic and nonischemic regions from the left ventricle of the same heart was compared in nine human subjects. Maximal oxidative phosphorylation capacity in fresh muscle fibers was lower in ischemic compared...

  19. Mitochondrial optic neuropathies – Disease mechanisms and therapeutic strategies

    Science.gov (United States)

    Yu-Wai-Man, Patrick; Griffiths, Philip G.; Chinnery, Patrick F.

    2011-01-01

    paraplegia, and multiple sclerosis, where mitochondrial dysfunction is also thought to be an important pathophysiological player. A number of vertebrate and invertebrate disease models has recently been established to circumvent the lack of human tissues, and these have already provided considerable insight by allowing direct RGC experimentation. The ultimate goal is to translate these research advances into clinical practice and new treatment strategies are currently being investigated to improve the visual prognosis for patients with mitochondrial optic neuropathies. PMID:21112411

  20. Mitochondrial transcription factor A protects human retinal ...

    African Journals Online (AJOL)

    Purpose: To investigate the impact of mitochondrial transcription factor A (TFAM), as a modulator of NF-κB, on proliferation of hypoxia-induced human retinal endothelial cell (HREC), and the probable mechanism. Methods: After exposure to hypoxia (1 % O2) for 5 days, cell proliferation and cell cycle of HREC were ...

  1. Inhibiting cytosolic translation and autophagy improves health in mitochondrial disease.

    Science.gov (United States)

    Peng, Min; Ostrovsky, Julian; Kwon, Young Joon; Polyak, Erzsebet; Licata, Joseph; Tsukikawa, Mai; Marty, Eric; Thomas, Jeffrey; Felix, Carolyn A; Xiao, Rui; Zhang, Zhe; Gasser, David L; Argon, Yair; Falk, Marni J

    2015-09-01

    Mitochondrial respiratory chain (RC) disease therapies directed at intra-mitochondrial pathology are largely ineffective. Recognizing that RC dysfunction invokes pronounced extra-mitochondrial transcriptional adaptations, particularly involving dysregulated translation, we hypothesized that translational dysregulation is itself contributing to the pathophysiology of RC disease. Here, we investigated the activities, and effects from direct inhibition, of a central translational regulator (mTORC1) and its downstream biological processes in diverse genetic and pharmacological models of RC disease. Our data identify novel mechanisms underlying the cellular pathogenesis of RC dysfunction, including the combined induction of proteotoxic stress, the ER stress response and autophagy. mTORC1 inhibition with rapamycin partially ameliorated renal disease in B6.Pdss2(kd/kd) mice with complexes I-III/II-III deficiencies, improved viability and mitochondrial physiology in gas-1(fc21) nematodes with complex I deficiency, and rescued viability across a variety of RC-inhibited human cells. Even more effective was probucol, a PPAR-activating anti-lipid drug that we show also inhibits mTORC1. However, directly inhibiting mTORC1-regulated downstream activities yielded the most pronounced and sustained benefit. Partial inhibition of translation by cycloheximide, or of autophagy by lithium chloride, rescued viability, preserved cellular respiratory capacity and induced mitochondrial translation and biogenesis. Cycloheximide also ameliorated proteotoxic stress via a uniquely selective reduction of cytosolic protein translation. RNAseq-based transcriptome profiling of treatment effects in gas-1(fc21) mutants provide further evidence that these therapies effectively restored altered translation and autophagy pathways toward that of wild-type animals. Overall, partially inhibiting cytosolic translation and autophagy offer novel treatment strategies to improve health across the diverse array

  2. Redox metabolism abnormalities in autistic children associated with mitochondrial disease

    National Research Council Canada - National Science Library

    Frye, R E; Delatorre, R; Taylor, H; Slattery, J; Melnyk, S; Chowdhury, N; James, S J

    2013-01-01

    ...), including mitochondrial disease (MD) and abnormal redox metabolism. Despite the close connection between mitochondrial dysfunction and oxidative stress, the relation between MD and oxidative stress in children with ASD has not been studied...

  3. Models of plasma membrane organization can be applied to mitochondrial membranes to target human health and disease with polyunsaturated fatty acids.

    Science.gov (United States)

    Raza Shaikh, Saame; Brown, David A

    2013-01-01

    Bioactive n-3 polyunsaturated fatty acids (PUFA), abundant in fish oil, have potential for treating symptoms associated with inflammatory and metabolic disorders; therefore, it is essential to determine their fundamental molecular mechanisms. Recently, several labs have demonstrated the n-3 PUFA docosahexaenoic acid (DHA) exerts anti-inflammatory effects by targeting the molecular organization of plasma membrane microdomains. Here we briefly review the evidence that DHA reorganizes the spatial distribution of microdomains in several model systems. We then emphasize how models on DHA and plasma membrane microdomains can be applied to mitochondrial membranes. We discuss the role of DHA acyl chains in regulating mitochondrial lipid-protein clustering, and how these changes alter several aspects of mitochondrial function. In particular, we summarize effects of DHA on mitochondrial respiration, electron leak, permeability transition, and mitochondrial calcium handling. Finally, we conclude by postulating future experiments that will augment our understanding of DHA-dependent membrane organization in health and disease. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. The mitochondrial Italian Human Proteome Project initiative (mt-HPP).

    Science.gov (United States)

    Urbani, Andrea; De Canio, Michele; Palmieri, Ferdinando; Sechi, Salvatore; Bini, Luca; Castagnola, Massimo; Fasano, Mauro; Modesti, Alessandra; Roncada, Paola; Timperio, Anna Maria; Bonizzi, Luigi; Brunori, Maurizio; Cutruzzolà, Francesca; De Pinto, Vito; Di Ilio, Carmine; Federici, Giorgio; Folli, Franco; Foti, Salvatore; Gelfi, Cecilia; Lauro, Davide; Lucacchini, Antonio; Magni, Fulvio; Messana, Irene; Pandolfi, Pier Paolo; Papa, Sergio; Pucci, Piero; Sacchetta, Paolo

    2013-08-01

    Mitochondria carry maternally inherited genetic material, called the mitochondrial genome (mtDNA), which can be defined as the 25th human chromosome. The chromosome-centric Human Proteome Project (c-HPP) has initially focused its activities addressing the characterization and quantification of the nuclear encoded proteins. Following the last International HUPO Congress in Boston (September 2012) it was clear that however small the mitochondrial chromosome is, it plays an important role in many biological and physiopathological functions. Mutations in the mtDNA have been shown to be associated with dozens of unexplained disorders and the information contained in the mtDNA should be of major relevance to the understanding of many human diseases. Within this paper we describe the Italian initiative of the Human Proteome Project dedicated to mitochondria as part of both programs: chromosome-centric (c-HPP) and Biology/Disease (B/D-HPP). The mt-HPP has finally shifted the attention of the HUPO community outside the nuclear chromosomes with the general purpose to highlight the mitochondrial processes influencing the human health. Following this vision and considering the large interest and evidence collected on the non-Mendelian heredity of Homo sapiens associated with mt-chromosome and with the microbial commensal ecosystem constituting our organism we may speculate that this program will represent an initial step toward other HPP initiatives focusing on human phenotypic heredity.

  5. Mutations in mitochondrial DNA regulate mitochondrial diseases and metastasis but do not regulate aging.

    Science.gov (United States)

    Hayashi, Jun-Ichi; Hashizume, Osamu; Ishikawa, Kaori; Shimizu, Akinori

    2016-06-01

    The mitochondria theory of aging proposes that accumulation of mitochondrial DNA (mtDNA) with pathogenic mutations, and the resultant respiration defects, are responsible not only for mitochondrial diseases but also for aging and age-associated disorders, including tumor development. This theory is partly supported by results obtained from our transmitochondrial mice (mito-mice), which harbour mtDNA with mutations that are orthologous to those found in patients with mitochondrial diseases: mito-mice express disease phenotypes only when they express respiration defects caused by accumulation of mutated mtDNA. With regard to tumor development, specific mtDNA mutations that induce reactive oxygen species (ROS) enhance malignant transformation of lung carcinoma cells to cells with high metastatic potential. However, age-associated respiration defects in elderly human fibroblasts are due not to mtDNA mutations but to epigenetic regulation of nuclear-coded genes, as indicated by the fact that normal respiratory function is restored by reprogramming of elderly fibroblasts. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Dimethyl fumarate mediates Nrf2-dependent mitochondrial biogenesis in mice and humans.

    Science.gov (United States)

    Hayashi, Genki; Jasoliya, Mittal; Sahdeo, Sunil; Saccà, Francesco; Pane, Chiara; Filla, Alessandro; Marsili, Angela; Puorro, Giorgia; Lanzillo, Roberta; Brescia Morra, Vincenzo; Cortopassi, Gino

    2017-08-01

    The induction of mitochondrial biogenesis could potentially alleviate mitochondrial and muscle disease. We show here that dimethyl fumarate (DMF) dose-dependently induces mitochondrial biogenesis and function dosed to cells in vitro, and also dosed in vivo to mice and humans. The induction of mitochondrial gene expression is more dependent on DMF's target Nrf2 than hydroxycarboxylic acid receptor 2 (HCAR2). Thus, DMF induces mitochondrial biogenesis primarily through its action on Nrf2, and is the first drug demonstrated to increase mitochondrial biogenesis with in vivo human dosing. This is the first demonstration that mitochondrial biogenesis is deficient in Multiple Sclerosis patients, which could have implications for MS pathophysiology and therapy. The observation that DMF stimulates mitochondrial biogenesis, gene expression and function suggests that it could be considered for mitochondrial disease therapy and/or therapy in muscle disease in which mitochondrial function is important. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

    Directory of Open Access Journals (Sweden)

    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

  8. Mitochondrial respiration in human viable platelets-Methodology and influence of gender, age and storage

    DEFF Research Database (Denmark)

    Sjövall, Fredrik; Ehinger, Johannes K H; Marelsson, Sigurður E

    2013-01-01

    Studying whole cell preparations with intact mitochondria and respiratory complexes has a clear benefit compared to isolated or disrupted mitochondria due to the dynamic interplay between mitochondria and other cellular compartments. Platelet mitochondria have a potential to serve as a source...... of human viable mitochondria when studying mitochondrial physiology and pathogenic mechanisms, as well as for the diagnostics of mitochondrial diseases. The objective of the present study was to perform a detailed evaluation of platelet mitochondrial respiration using high-resolution respirometry. Further...

  9. The Use of Neuroimaging in the Diagnosis of Mitochondrial Disease

    Science.gov (United States)

    Friedman, Seth D.; Shaw, Dennis W. W.; Ishak, Gisele; Gropman, Andrea L.; Saneto, Russell P.

    2010-01-01

    Mutations in nuclear and mitochondrial DNA impacting mitochondrial function result in disease manifestations ranging from early death to abnormalities in all major organ systems and to symptoms that can be largely confined to muscle fatigue. The definitive diagnosis of a mitochondrial disorder can be difficult to establish. When the constellation…

  10. Molecular regulation of mitochondrial dynamics in cardiac disease.

    Science.gov (United States)

    Nan, Jinliang; Zhu, Wei; Rahman, M S; Liu, Mingfei; Li, Dan; Su, Shengan; Zhang, Na; Hu, Xinyang; Yu, Hong; Gupta, Mahesh P; Wang, Jian'an

    2017-07-01

    Mitochondrial homeostasis is critical for keeping functional heart in response to metabolic or environmental stresses. Mitochondrial fission and fusion (mitochondrial dynamics) play essential roles in maintaining mitochondrial homeostasis, defects in mitochondrial dynamics lead to cardiac diseases such as ischemia-reperfusion injury (IRI), heart failure and diabetic cardiomyopathy. Mitochondrial dynamics is determined by mitochondrial fission and fusion proteins, including OPA1, mitofusins and Drp1. These proteins are tightly regulated by a series of signaling pathways through different aspects such as transcription, post translation modifications (PTMs) and proteasome-dependent protein degradation. By modulating these mitochondrial fission and fusion proteins, mitochondria fine-tune their metabolic status to meet the energy demands of the heart. Moreover, these mitochondrial fission and fusion proteins are essential for mediating mitochondrial autophagy (mitophagy), leading to clearance of damaged mitochondria to maintain a healthy population of mitochondria in heart under stressed conditions. Mitochondrial dynamics dependent improvement in mitochondrial metabolism and quality could partially reverse the pathological conditions of heart. This review describes an overview of mechanisms on mitochondrial dynamics regulation and provides potential therapeutic targets for treating cardiovascular diseases. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Mitochondrial Iron-Sulfur Cluster Dysfunction In Neurodegenerative Disease

    Directory of Open Access Journals (Sweden)

    Grazia eIsaya

    2014-03-01

    Full Text Available Growing evidence supports a role for mitochondrial iron metabolism in the pathophysiology of neurodegenerative disorders such as Friedreich ataxia and Parkinson disease as well as in the motor and cognitive decline associated with the aging process. Iron-sulfur enzyme deficits and regional iron accumulation have been observed in each of these conditions. In spite of significant etiological, clinical and pathological differences that exist between Friedreich ataxia and Parkinson disease, it is possible that defects in mitochondrial iron-sulfur clusters biogenesis represent a common underlying mechanism leading to abnormal intracellular iron distribution with mitochondrial iron accumulation, OXPHOS deficits and oxidative stress in susceptible cells and specific regions of the nervous system. Moreover, a similar mechanism may contribute to the age-dependent iron accumulation that occurs in certain brain regions such as the globus pallidus and the substantia nigra. Targeting chelatable iron and reactive oxygen species appear as possible therapeutic options for Friedreich ataxia and Parkinson disease, and possibly other age-related neurodegenerative conditions. However, new technology to interrogate iron-sulfur cluster synthesis in humans is needed to (i assess how defects in this pathway contribute to the natural history of neurodegenerative disorders and (ii develop treatments to correct those defects early in the disease process, before they cause irreversible neuronal cell damage.

  12. May “Mitochondrial Eve” and Mitochondrial Haplogroups Play a Role in Neurodegeneration and Alzheimer's Disease?

    Directory of Open Access Journals (Sweden)

    Elena Caldarazzo Ienco

    2011-01-01

    Full Text Available Mitochondria, the powerhouse of the cell, play a critical role in several metabolic processes and apoptotic pathways. Multiple evidences suggest that mitochondria may be crucial in ageing-related neurodegenerative diseases. Moreover, mitochondrial haplogroups have been linked to multiple area of medicine, from normal ageing to diseases, including neurodegeneration. Polymorphisms within the mitochondrial genome might lead to impaired energy generation and to increased amount of reactive oxygen species, having either susceptibility or protective role in several diseases. Here, we highlight the role of the mitochondrial haplogroups in the pathogenetic cascade leading to diseases, with special attention to Alzheimer's disease.

  13. The Alzheimer's Disease Mitochondrial Cascade Hypothesis: Progress and Perspectives

    Science.gov (United States)

    Swerdlow, Russell H.; Burns, Jeffrey M.; Khan, Shaharyar M.

    2013-01-01

    Ten years ago we first proposed the Alzheimer's disease (AD) mitochondrial cascade hypothesis. This hypothesis maintains gene inheritance defines an individual's baseline mitochondrial function; inherited and environmental factors determine rates at which mitochondrial function changes over time; and baseline mitochondrial function and mitochondrial change rates influence AD chronology. Our hypothesis unequivocally states in sporadic, late-onset AD, mitochondrial function affects amyloid precursor protein (APP) expression, APP processing, or beta amyloid (Aβ) accumulation and argues if an amyloid cascade truly exists, mitochondrial function triggers it. We now review the state of the mitochondrial cascade hypothesis, and discuss it in the context of recent AD biomarker studies, diagnostic criteria, and clinical trials. Our hypothesis predicts biomarker changes reflect brain aging, new AD definitions clinically stage brain aging, and removing brain Aβ at any point will marginally impact cognitive trajectories. Our hypothesis, therefore, offers unique perspective into what sporadic, late-onset AD is and how to best treat it. PMID:24071439

  14. The Alzheimer's disease mitochondrial cascade hypothesis: progress and perspectives.

    Science.gov (United States)

    Swerdlow, Russell H; Burns, Jeffrey M; Khan, Shaharyar M

    2014-08-01

    Ten years ago we first proposed the Alzheimer's disease (AD) mitochondrial cascade hypothesis. This hypothesis maintains that gene inheritance defines an individual's baseline mitochondrial function; inherited and environmental factors determine rates at which mitochondrial function changes over time; and baseline mitochondrial function and mitochondrial change rates influence AD chronology. Our hypothesis unequivocally states in sporadic, late-onset AD, mitochondrial function affects amyloid precursor protein (APP) expression, APP processing, or beta amyloid (Aβ) accumulation and argues if an amyloid cascade truly exists, mitochondrial function triggers it. We now review the state of the mitochondrial cascade hypothesis, and discuss it in the context of recent AD biomarker studies, diagnostic criteria, and clinical trials. Our hypothesis predicts that biomarker changes reflect brain aging, new AD definitions clinically stage brain aging, and removing brain Aβ at any point will marginally impact cognitive trajectories. Our hypothesis, therefore, offers unique perspective into what sporadic, late-onset AD is and how to best treat it. © 2013.

  15. Dysregulation of Mitochondrial Calcium Signaling and Superoxide Flashes Cause Mitochondrial Genomic DNA Damage in Huntington Disease*

    Science.gov (United States)

    Wang, Jiu-Qiang; Chen, Qian; Wang, Xianhua; Wang, Qiao-Chu; Wang, Yun; Cheng, He-Ping; Guo, Caixia; Sun, Qinmiao; Chen, Quan; Tang, Tie-Shan

    2013-01-01

    Huntington disease (HD) is an inherited, fatal neurodegenerative disorder characterized by the progressive loss of striatal medium spiny neurons. Indications of oxidative stress are apparent in brain tissues from both HD patients and HD mouse models; however, the origin of this oxidant stress remains a mystery. Here, we used a yeast artificial chromosome transgenic mouse model of HD (YAC128) to investigate the potential connections between dysregulation of cytosolic Ca2+ signaling and mitochondrial oxidative damage in HD cells. We found that YAC128 mouse embryonic fibroblasts exhibit a strikingly higher level of mitochondrial matrix Ca2+ loading and elevated superoxide generation compared with WT cells, indicating that both mitochondrial Ca2+ signaling and superoxide generation are dysregulated in HD cells. The excessive mitochondrial oxidant stress is critically dependent on mitochondrial Ca2+ loading in HD cells, because blocking mitochondrial Ca2+ uptake abolished elevated superoxide generation. Similar results were obtained using neurons from HD model mice and fibroblast cells from HD patients. More importantly, mitochondrial Ca2+ loading in HD cells caused a 2-fold higher level of mitochondrial genomic DNA (mtDNA) damage due to the excessive oxidant generation. This study provides strong evidence to support a new causal link between dysregulated mitochondrial Ca2+ signaling, elevated mitochondrial oxidant stress, and mtDNA damage in HD. Our results also indicate that reducing mitochondrial Ca2+ uptake could be a therapeutic strategy for HD. PMID:23250749

  16. Yeast as a system for modeling mitochondrial disease mechanisms and discovering therapies

    Directory of Open Access Journals (Sweden)

    Jean-Paul Lasserre

    2015-06-01

    Full Text Available Mitochondrial diseases are severe and largely untreatable. Owing to the many essential processes carried out by mitochondria and the complex cellular systems that support these processes, these diseases are diverse, pleiotropic, and challenging to study. Much of our current understanding of mitochondrial function and dysfunction comes from studies in the baker's yeast Saccharomyces cerevisiae. Because of its good fermenting capacity, S. cerevisiae can survive mutations that inactivate oxidative phosphorylation, has the ability to tolerate the complete loss of mitochondrial DNA (a property referred to as ‘petite-positivity’, and is amenable to mitochondrial and nuclear genome manipulation. These attributes make it an excellent model system for studying and resolving the molecular basis of numerous mitochondrial diseases. Here, we review the invaluable insights this model organism has yielded about diseases caused by mitochondrial dysfunction, which ranges from primary defects in oxidative phosphorylation to metabolic disorders, as well as dysfunctions in maintaining the genome or in the dynamics of mitochondria. Owing to the high level of functional conservation between yeast and human mitochondrial genes, several yeast species have been instrumental in revealing the molecular mechanisms of pathogenic human mitochondrial gene mutations. Importantly, such insights have pointed to potential therapeutic targets, as have genetic and chemical screens using yeast.

  17. Optimal micronutrients delay mitochondrial decay and age-associated diseases.

    Science.gov (United States)

    Ames, Bruce N

    2010-01-01

    Three of our research efforts are reviewed, which suggest that optimizing metabolism will delay aging and the diseases of aging in humans. (1) Research on delay of the mitochondrial decay of aging by supplementing rats with lipoic acid and acetyl carnitine. (2) The triage theory, which posits that modest micronutrient deficiencies (common in much of the population) accelerate molecular aging, including mitochondrial decay, and supportive evidence, including an analysis in depth of vitamin K, that suggests the importance of achieving optimal micronutrient intake for longevity. (3) The finding that decreased enzyme binding constants (increased Km) for coenzymes (or substrates) can result from protein deformation and loss of function due to loss of membrane fluidity with age, or to polymorphisms or mutation. The loss of enzyme function can be ameliorated by high doses of a B vitamin, which raises coenzyme levels, and indicates the importance of understanding the effects of age, or polymorphisms, on micronutrient requirements. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  18. Targeting mitochondrial phenotypes for non-communicable diseases

    Directory of Open Access Journals (Sweden)

    Zhengtang Qi

    2016-06-01

    Full Text Available The concept that “Exercise is Medicine” has been challenged by the rising prevalence of non-communicable chronic diseases (NCDs. This is partly due to the fact that the underlying mechanisms of how exercise influences energy homeostasis and counteracts high-fat diets and physical inactivity is complex and remains relatively poorly understood on a molecular level. In addition to genetic polymorphisms in humans that lead to gross variations in responsiveness to exercise, adaptation in mitochondrial networks is central to physical activity, inactivity, and diet. To harness the benefits of exercise for NCDs, much work still needs to be done to improve health effectively on a societal level such as developing personalized exercise interventions aided by advances in high-throughput genomics, proteomics, and metabolomics. We propose that understanding the mitochondrial phenotype according to the molecular information of genotypes, lifestyles, and exercise responsiveness in individuals will optimize exercise effects for prevention of NCDs.

  19. Transfer RNA and human disease

    Directory of Open Access Journals (Sweden)

    Jamie A Abbott

    2014-06-01

    Full Text Available Pathological mutations in tRNA genes and tRNA processing enzymes are numerous and result in very complicated clinical phenotypes. Mitochondrial tRNA (mt-tRNA genes are hotspots for pathological mutations and over 200 mt-tRNA mutations have been linked to various disease states. Often these mutations prevent tRNA aminoacylation. Disrupting this primary function affects protein synthesis and the expression, folding, and function of oxidative phosphorylation enzymes. Mitochondrial tRNA mutations manifest in a wide panoply of diseases related to cellular energetics, including COX deficiency (cytochrome C oxidase, mitochondrial myopathy, MERRF (Myoclonic Epilepsy with Ragged Red Fibers, and MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. Diseases caused by mt-tRNA mutations can also affect very specific tissue types, as in the case of neurosensory non-syndromic hearing loss and pigmentary retinopathy, diabetes mellitus, and hypertrophic cardiomyopathy. Importantly, mitochondrial heteroplasmy plays a role in disease severity and age of onset as well. Not surprisingly, mutations in enzymes that modify cytoplasmic and mitochondrial tRNAs are also linked to a diverse range of clinical phenotypes. In addition to compromised aminoacylation of the tRNAs, mutated modifying enzymes can also impact tRNA expression and abundance, tRNA modifications, tRNA folding, and even tRNA maturation (e.g., splicing. Some of these pathological mutations in tRNAs and processing enzymes are likely to affect non-canonical tRNA functions, and contribute to the diseases without significantly impacting on translation. This chapter will review recent literature on the relation of mitochondrial and cytoplasmic tRNA, and enzymes that process tRNAs, to human disease. We explore the mechanisms involved in the clinical presentation of these various diseases with an emphasis on neurological disease.

  20. Mutations in mitochondrial DNA causing tubulointerstitial kidney disease.

    Directory of Open Access Journals (Sweden)

    Thomas M Connor

    2017-03-01

    Full Text Available Tubulointerstitial kidney disease is an important cause of progressive renal failure whose aetiology is incompletely understood. We analysed a large pedigree with maternally inherited tubulointerstitial kidney disease and identified a homoplasmic substitution in the control region of the mitochondrial genome (m.547A>T. While mutations in mtDNA coding sequence are a well recognised cause of disease affecting multiple organs, mutations in the control region have never been shown to cause disease. Strikingly, our patients did not have classical features of mitochondrial disease. Patient fibroblasts showed reduced levels of mitochondrial tRNAPhe, tRNALeu1 and reduced mitochondrial protein translation and respiration. Mitochondrial transfer demonstrated mitochondrial transmission of the defect and in vitro assays showed reduced activity of the heavy strand promoter. We also identified further kindreds with the same phenotype carrying a homoplasmic mutation in mitochondrial tRNAPhe (m.616T>C. Thus mutations in mitochondrial DNA can cause maternally inherited renal disease, likely mediated through reduced function of mitochondrial tRNAPhe.

  1. All-Trans-Retinoic Acid Enhances Mitochondrial Function in Models of Human Liver

    Science.gov (United States)

    Tripathy, Sasmita; Chapman, John D; Han, Chang Y; Hogarth, Cathryn A; Arnold, Samuel L.M.; Onken, Jennifer; Kent, Travis; Goodlett, David R

    2016-01-01

    All-trans-retinoic acid (atRA) is the active metabolite of vitamin A. The liver is the main storage organ of vitamin A, but activation of the retinoic acid receptors (RARs) in mouse liver and in human liver cell lines has also been shown. Although atRA treatment improves mitochondrial function in skeletal muscle in rodents, its role in modulating mitochondrial function in the liver is controversial, and little data are available regarding the human liver. The aim of this study was to determine whether atRA regulates hepatic mitochondrial activity. atRA treatment increased the mRNA and protein expression of multiple components of mitochondrial β-oxidation, tricarboxylic acid (TCA) cycle, and respiratory chain. Additionally, atRA increased mitochondrial biogenesis in human hepatocytes and in HepG2 cells with and without lipid loading based on peroxisome proliferator activated receptor gamma coactivator 1α and 1β and nuclear respiratory factor 1 mRNA and mitochondrial DNA quantification. atRA also increased β-oxidation and ATP production in HepG2 cells and in human hepatocytes. Knockdown studies of RARα, RARβ, and PPARδ revealed that the enhancement of mitochondrial biogenesis and β-oxidation by atRA requires peroxisome proliferator activated receptor delta. In vivo in mice, atRA treatment increased mitochondrial biogenesis markers after an overnight fast. Inhibition of atRA metabolism by talarozole, a cytochrome P450 (CYP) 26 specific inhibitor, increased the effects of atRA on mitochondrial biogenesis markers in HepG2 cells and in vivo in mice. These studies show that atRA regulates mitochondrial function and lipid metabolism and that increasing atRA concentrations in human liver via CYP26 inhibition may increase mitochondrial biogenesis and fatty acid β-oxidation and provide therapeutic benefit in diseases associated with mitochondrial dysfunction. PMID:26921399

  2. Mitochondrial tRNA cleavage by tRNA-targeting ribonuclease causes mitochondrial dysfunction observed in mitochondrial disease

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Tetsuhiro, E-mail: atetsu@mail.ecc.u-tokyo.ac.jp; Shimizu, Ayano; Takahashi, Kazutoshi; Hidaka, Makoto; Masaki, Haruhiko, E-mail: amasaki@mail.ecc.u-tokyo.ac.jp

    2014-08-15

    Highlights: • MTS-tagged ribonuclease was translocated successfully to the mitochondrial matrix. • MTS-tagged ribonuclease cleaved mt tRNA and reduced COX activity. • Easy and reproducible method of inducing mt tRNA dysfunction. - Abstract: Mitochondrial DNA (mtDNA) is a genome possessed by mitochondria. Since reactive oxygen species (ROS) are generated during aerobic respiration in mitochondria, mtDNA is commonly exposed to the risk of DNA damage. Mitochondrial disease is caused by mitochondrial dysfunction, and mutations or deletions on mitochondrial tRNA (mt tRNA) genes are often observed in mtDNA of patients with the disease. Hence, the correlation between mt tRNA activity and mitochondrial dysfunction has been assessed. Then, cybrid cells, which are constructed by the fusion of an enucleated cell harboring altered mtDNA with a ρ{sup 0} cell, have long been used for the analysis due to difficulty in mtDNA manipulation. Here, we propose a new method that involves mt tRNA cleavage by a bacterial tRNA-specific ribonuclease. The ribonuclease tagged with a mitochondrial-targeting sequence (MTS) was successfully translocated to the mitochondrial matrix. Additionally, mt tRNA cleavage, which resulted in the decrease of cytochrome c oxidase (COX) activity, was observed.

  3. Imaging mitochondrial dynamics in human skin reveals depth-dependent hypoxia and malignant potential for diagnosis.

    Science.gov (United States)

    Pouli, Dimitra; Balu, Mihaela; Alonzo, Carlo A; Liu, Zhiyi; Quinn, Kyle P; Rius-Diaz, Francisca; Harris, Ronald M; Kelly, Kristen M; Tromberg, Bruce J; Georgakoudi, Irene

    2016-11-30

    Active changes in mitochondrial structure and organization facilitate cellular homeostasis. Because aberrant mitochondrial dynamics are implicated in a variety of human diseases, their assessment is potentially useful for diagnosis, therapy, and disease monitoring. Because current techniques for evaluating mitochondrial morphology are invasive or necessitate mitochondria-specific dyes, their clinical translation is limited. We report that mitochondrial dynamics can be monitored in vivo, within intact human skin by relying entirely on endogenous two-photon-excited fluorescence from the reduced metabolic coenzyme nicotinamide adenine dinucleotide (NADH). We established the sensitivity of this approach with in vivo, fast temporal studies of arterial occlusion-reperfusion, which revealed acute changes in the mitochondrial metabolism and dynamics of the lower human epidermal layers. In vitro hypoxic-reperfusion studies validated that the in vivo outcomes were a result of NADH fluorescence changes. To demonstrate the diagnostic potential of this approach, we evaluated healthy and cancerous human skin epithelia. Healthy tissues displayed consistent, depth-dependent morphological and mitochondrial organization patterns that varied with histological stratification and intraepithelial mitochondrial protein expression. In contrast, these consistent patterns were absent in cancerous skin lesions. We exploited these differences to successfully differentiate healthy from cancerous tissues using a predictive classification approach. Collectively, these results demonstrate that our label-free, automated, near real-time assessments of mitochondrial organization-relying solely on endogenous contrast-could be useful for accurate, noninvasive in vivo diagnosis. Copyright © 2016, American Association for the Advancement of Science.

  4. Mitochondrial Dysfunction: Different Routes to Alzheimer’s Disease Therapy

    Directory of Open Access Journals (Sweden)

    Pasquale Picone

    2014-01-01

    Full Text Available Mitochondria are dynamic ATP-generating organelle which contribute to many cellular functions including bioenergetics processes, intracellular calcium regulation, alteration of reduction-oxidation potential of cells, free radical scavenging, and activation of caspase mediated cell death. Mitochondrial functions can be negatively affected by amyloid β peptide (Aβ, an important component in Alzheimer’s disease (AD pathogenesis, and Aβ can interact with mitochondria and cause mitochondrial dysfunction. One of the most accepted hypotheses for AD onset implicates that mitochondrial dysfunction and oxidative stress are one of the primary events in the insurgence of the pathology. Here, we examine structural and functional mitochondrial changes in presence of Aβ. In particular we review data concerning Aβ import into mitochondrion and its involvement in mitochondrial oxidative stress, bioenergetics, biogenesis, trafficking, mitochondrial permeability transition pore (mPTP formation, and mitochondrial protein interaction. Moreover, the development of AD therapy targeting mitochondria is also discussed.

  5. Human mitochondrial ribosomal protein MRPL12 interacts directly with mitochondrial RNA polymerase to modulate mitochondrial gene expression.

    Science.gov (United States)

    Wang, Zhibo; Cotney, Justin; Shadel, Gerald S

    2007-04-27

    The core human mitochondrial transcription machinery comprises a single subunit bacteriophage-related RNA polymerase, POLRMT, the high mobility group box DNA-binding protein h-mtTFA/TFAM, and two transcriptional co-activator proteins, h-mtTFB1 and h-mtTFB2 that also have rRNA methyltransferase activity. Recapitulation of specific initiation of transcription in vitro can be achieved by a complex of POL-RMT, h-mtTFA, and either h-mtTFB1 or h-mtTFB2. However, the nature of mitochondrial transcription complexes in vivo and the potential involvement of additional proteins in the transcription process in human mitochondria have not been extensively investigated. In Saccharomyces cerevisiae, transcription and translation are physically coupled via the formation of a multiprotein complex nucleated by the binding of Nam1p to the amino-terminal domain of mtRNA polymerase (Rpo41p). This model system paradigm led us to search for proteins that interact with POLRMT to regulate mitochondrial gene expression in humans. Using an affinity capture strategy to identify POL-RMT-binding proteins, we identified mitochondrial ribosomal protein L7/L12 (MRPL12) as a protein in HeLa mitochondrial extracts that interacts specifically with POLRMT in vitro. Purified recombinant MRPL12 binds to POLRMT and stimulates mitochondrial transcription activity in vitro, demonstrating that this interaction is both direct and functional. Finally, from HeLa cells that overexpress FLAG epitope-tagged MRPL12, increased steady-state levels of mtDNA-encoded transcripts are observed and MRPL12-POLRMT complexes can be co-immunoprecipitated, providing strong evidence that this interaction enhances mitochondrial transcription or RNA stability in vivo. We speculate that the MRPL12 interaction with POLRMT is likely part of a novel regulatory mechanism that coordinates mitochondrial transcription with translation and/or ribosome biogenesis during human mitochondrial gene expression.

  6. Cardiac aging in mice and humans: the role of mitochondrial oxidative stress.

    Science.gov (United States)

    Dai, Dao-Fu; Rabinovitch, Peter S

    2009-10-01

    Age is a major risk factor for cardiovascular diseases, not only because it prolongs exposure to several other cardiovascular risks, but also owing to intrinsic cardiac aging, which reduces cardiac functional reserve, predisposes the heart to stress, and contributes to increased cardiovascular mortality in the elderly. Intrinsic cardiac aging in the murine model closely recapitulates age-related cardiac changes in humans, including left ventricular hypertrophy, fibrosis, and diastolic dysfunction. Cardiac aging in mice is accompanied by accumulation of mitochondrial protein oxidation, increased mitochondrial DNA mutations, increased mitochondrial biogenesis, as well as decreased cardiac SERCA2 protein. All of these age-related changes are significantly attenuated in mice overexpressing catalase targeted to mitochondria. These findings demonstrate the critical role of mitochondrial reactive oxygen species in cardiac aging and support the potential application of mitochondrial antioxidants to cardiac aging and age-related cardiovascular diseases.

  7. Pharmacological NAD-Boosting Strategies Improve Mitochondrial Homeostasis in Human Complex I-Mutant Fibroblasts.

    Science.gov (United States)

    Felici, Roberta; Lapucci, Andrea; Cavone, Leonardo; Pratesi, Sara; Berlinguer-Palmini, Rolando; Chiarugi, Alberto

    2015-06-01

    Mitochondrial disorders are devastating genetic diseases for which efficacious therapies are still an unmet need. Recent studies report that increased availability of intracellular NAD obtained by inhibition of the NAD-consuming enzyme poly(ADP-ribose) polymerase (PARP)-1 or supplementation with the NAD-precursor nicotinamide riboside (NR) ameliorates energetic derangement and symptoms in mouse models of mitochondrial disorders. Whether these pharmacological approaches also improve bioenergetics of human cells harboring mitochondrial defects is unknown. It is also unclear whether the same signaling cascade is prompted by PARP-1 inhibitors and NR supplementation to improve mitochondrial homeostasis. Here, we show that human fibroblasts mutant for the NADH dehydrogenase (ubiquinone) Fe-S protein 1 (NDUFS1) subunit of respiratory complex I have similar ATP, NAD, and mitochondrial content compared with control cells, but show reduced mitochondrial membrane potential. Interestingly, mutant cells also show increased transcript levels of mitochondrial DNA but not nuclear DNA respiratory complex subunits, suggesting activation of a compensatory response. At variance with prior work in mice, however, NR supplementation, but not PARP-1 inhibition, increased intracellular NAD content in NDUFS1 mutant human fibroblasts. Conversely, PARP-1 inhibitors, but not NR supplementation, increased transcription of mitochondrial transcription factor A and mitochondrial DNA-encoded respiratory complexes constitutively induced in mutant cells. Still, both NR and PARP-1 inhibitors restored mitochondrial membrane potential and increased organelle content as well as oxidative activity of NDUFS1-deficient fibroblasts. Overall, data provide the first evidence that in human cells harboring a mitochondrial respiratory defect exposure to NR or PARP-1, inhibitors activate different signaling pathways that are not invariantly prompted by NAD increases, but equally able to improve energetic

  8. Diagnostic Approach in Infants and Children with Mitochondrial Diseases

    Directory of Open Access Journals (Sweden)

    Ching-Shiang Chi

    2015-02-01

    The purpose of this study is to review the molecular classification scheme and associated phenotypes in infants and children with mitochondrial diseases, in addition to providing an overview of the basic biochemical reactions and genetic characteristics in the mitochondrion, clinical manifestations, and diagnostic methods. A diagnostic algorithm for identifying mitochondrial disorders in pediatric neurology patients is proposed.

  9. [Mitochondrial diseases; thinking beyond organ specialism necessary

    NARCIS (Netherlands)

    Smits, B.W.; Smeitink, J.A.M.; Engelen, B.G.M. van

    2008-01-01

    Mitochondrial disorders are caused by a defect in intracellular energy production. In general, these are multi-system disorders, predominantly affecting organs with high energy requirements. Due to the fact that mitochondrial disorders are not as rare as is generally assumed, and due to the

  10. Mitochondrial Bioenergetics Is Altered in Fibroblasts from Patients with Sporadic Alzheimer's Disease

    Directory of Open Access Journals (Sweden)

    María J. Pérez

    2017-10-01

    Full Text Available The identification of an early biomarker to diagnose Alzheimer's disease (AD remains a challenge. Neuropathological studies in animal and AD patients have shown that mitochondrial dysfunction is a hallmark of the development of the disease. Current studies suggest the use of peripheral tissues, like skin fibroblasts as a possibility to detect the early pathological alterations present in the AD brain. In this context, we studied mitochondrial function properties (bioenergetics and morphology in cultured fibroblasts obtained from AD, aged-match and young healthy patients. We observed that AD fibroblasts presented a significant reduction in mitochondrial length with important changes in the expression of proteins that control mitochondrial fusion. Moreover, AD fibroblasts showed a distinct alteration in proteolytic processing of OPA1, a master regulator of mitochondrial fusion, compared to control fibroblasts. Complementary to these changes AD fibroblasts showed a dysfunctional mitochondrial bioenergetics profile that differentiates these cells from aged-matched and young patient fibroblasts. Our findings suggest that the human skin fibroblasts obtained from AD patients could replicate mitochondrial impairment observed in the AD brain. These promising observations suggest that the analysis of mitochondrial bioenergetics could represent a promising strategy to develop new diagnostic methods in peripheral tissues of AD patients.

  11. Mitochondrial Bioenergetics Is Altered in Fibroblasts from Patients with Sporadic Alzheimer's Disease

    Science.gov (United States)

    Pérez, María J.; Ponce, Daniela P.; Osorio-Fuentealba, Cesar; Behrens, Maria I.; Quintanilla, Rodrigo A.

    2017-01-01

    The identification of an early biomarker to diagnose Alzheimer's disease (AD) remains a challenge. Neuropathological studies in animal and AD patients have shown that mitochondrial dysfunction is a hallmark of the development of the disease. Current studies suggest the use of peripheral tissues, like skin fibroblasts as a possibility to detect the early pathological alterations present in the AD brain. In this context, we studied mitochondrial function properties (bioenergetics and morphology) in cultured fibroblasts obtained from AD, aged-match and young healthy patients. We observed that AD fibroblasts presented a significant reduction in mitochondrial length with important changes in the expression of proteins that control mitochondrial fusion. Moreover, AD fibroblasts showed a distinct alteration in proteolytic processing of OPA1, a master regulator of mitochondrial fusion, compared to control fibroblasts. Complementary to these changes AD fibroblasts showed a dysfunctional mitochondrial bioenergetics profile that differentiates these cells from aged-matched and young patient fibroblasts. Our findings suggest that the human skin fibroblasts obtained from AD patients could replicate mitochondrial impairment observed in the AD brain. These promising observations suggest that the analysis of mitochondrial bioenergetics could represent a promising strategy to develop new diagnostic methods in peripheral tissues of AD patients. PMID:29056898

  12. Muscle mitochondrial capacity exceeds maximal oxygen delivery in humans

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Gnaiger, Erich; Calbet, Jose A L

    2011-01-01

    Across a wide range of species and body mass a close matching exists between maximal conductive oxygen delivery and mitochondrial respiratory rate. In this study we investigated in humans how closely in-vivo maximal oxygen consumption (VO(2) max) is matched to state 3 muscle mitochondrial respira...

  13. Mitochondrial proteomics on human fibroblasts for identification of metabolic imbalance and cellular stress

    Directory of Open Access Journals (Sweden)

    Bross Peter

    2009-05-01

    Full Text Available Abstract Background Mitochondrial proteins are central to various metabolic activities and are key regulators of apoptosis. Disturbance of mitochondrial proteins is therefore often associated with disease. Large scale protein data are required to capture the mitochondrial protein levels and mass spectrometry based proteomics is suitable for generating such data. To study the relative quantities of mitochondrial proteins in cells from cultivated human skin fibroblasts we applied a proteomic method based on nanoLC-MS/MS analysis of iTRAQ-labeled peptides. Results When fibroblast cultures were exposed to mild metabolic stress – by cultivation in galactose medium- the amount of mitochondria appeared to be maintained whereas the levels of individual proteins were altered. Proteins of respiratory chain complex I and IV were increased together with NAD+-dependent isocitrate dehydrogenase of the citric acid cycle illustrating cellular strategies to cope with altered energy metabolism. Furthermore, quantitative protein data, with a median standard error below 6%, were obtained for the following mitochondrial pathways: fatty acid oxidation, citric acid cycle, respiratory chain, antioxidant systems, amino acid metabolism, mitochondrial translation, protein quality control, mitochondrial morphology and apoptosis. Conclusion The robust analytical platform in combination with a well-defined compendium of mitochondrial proteins allowed quantification of single proteins as well as mapping of entire pathways. This enabled characterization of the interplay between metabolism and stress response in human cells exposed to mild stress.

  14. Involvement of the mitochondrial compartment in human NCL fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Pezzini, Francesco; Gismondi, Floriana [Department of Neurological, Psychological, Morphological and Motor Sciences, Divisions of Neurology (Child Neurology) and Neuropathology, University of Verona Medical School, Verona (Italy); Tessa, Alessandra [IRCCS Fondazione Stella Maris-Molecular Medicine Unit, Pisa (Italy); Tonin, Paola [Department of Neurological, Psychological, Morphological and Motor Sciences, Divisions of Neurology (Child Neurology) and Neuropathology, University of Verona Medical School, Verona (Italy); Carrozzo, Rosalba [IRCCS Bambino Gesu Hospital-Molecular Medicine Unit, Roma (Italy); Mole, Sara E. [MRC Laboratory for Molecular Cell Biology, Molecular Medicines Unit, UCL Institute of Child Health and Department of Genetics, Evolution and Environment, University College London (United Kingdom); Santorelli, Filippo M. [IRCCS Fondazione Stella Maris-Molecular Medicine Unit, Pisa (Italy); Simonati, Alessandro, E-mail: alessandro.simonati@univr.it [Department of Neurological, Psychological, Morphological and Motor Sciences, Divisions of Neurology (Child Neurology) and Neuropathology, University of Verona Medical School, Verona (Italy)

    2011-12-09

    Highlights: Black-Right-Pointing-Pointer Mitochondrial reticulum fragmentation occurs in human CLN1 and CLN6 fibroblasts. Black-Right-Pointing-Pointer Likewise mitochondrial shift-to periphery and decreased mitochondrial density are seen. Black-Right-Pointing-Pointer Enhanced caspase-mediated apoptosis occurs following STS treatment in CLN1 fibroblasts. -- Abstract: Neuronal ceroid lipofuscinosis (NCL) are a group of progressive neurodegenerative disorders of childhood, characterized by the endo-lysosomal storage of autofluorescent material. Impaired mitochondrial function is often associated with neurodegeneration, possibly related to the apoptotic cascade. In this study we investigated the possible effects of lysosomal accumulation on the mitochondrial compartment in the fibroblasts of two NCL forms, CLN1 and CLN6. Fragmented mitochondrial reticulum was observed in all cells by using the intravital fluorescent marker Mitotracker, mainly in the perinuclear region. This was also associated with intense signal from the lysosomal markers Lysotracker and LAMP2. Likewise, mitochondria appeared to be reduced in number and shifted to the cell periphery by electron microscopy; moreover the mitochondrial markers VDCA and COX IV were reduced following quantitative Western blot analysis. Whilst there was no evidence of increased cell death under basal condition, we observed a significant increase in apoptotic nuclei following Staurosporine treatment in CLN1 cells only. In conclusion, the mitochondrial compartment is affected in NCL fibroblasts invitro, and CLN1 cells seem to be more vulnerable to the negative effects of stressed mitochondrial membrane than CLN6 cells.

  15. NAD+-Dependent Activation of Sirt1 Corrects the Phenotype in a Mouse Model of Mitochondrial Disease

    Science.gov (United States)

    Cerutti, Raffaele; Pirinen, Eija; Lamperti, Costanza; Marchet, Silvia; Sauve, Anthony A.; Li, Wei; Leoni, Valerio; Schon, Eric A.; Dantzer, Françoise; Auwerx, Johan; Viscomi, Carlo; Zeviani, Massimo

    2014-01-01

    Summary Mitochondrial disorders are highly heterogeneous conditions characterized by defects of the mitochondrial respiratory chain. Pharmacological activation of mitochondrial biogenesis has been proposed as an effective means to correct the biochemical defects and ameliorate the clinical phenotype in these severely disabling, often fatal, disorders. Pathways related to mitochondrial biogenesis are targets of Sirtuin1, a NAD+-dependent protein deacetylase. As NAD+ boosts the activity of Sirtuin1 and other sirtuins, intracellular levels of NAD+ play a key role in the homeostatic control of mitochondrial function by the metabolic status of the cell. We show here that supplementation with nicotinamide riboside, a natural NAD+ precursor, or reduction of NAD+ consumption by inhibiting the poly(ADP-ribose) polymerases, leads to marked improvement of the respiratory chain defect and exercise intolerance of the Sco2 knockout/knockin mouse, a mitochondrial disease model characterized by impaired cytochrome c oxidase biogenesis. This strategy is potentially translatable into therapy of mitochondrial disorders in humans. PMID:24814483

  16. Emerging role of mitophagy in human diseases and physiology

    OpenAIRE

    Um, Jee-Hyun; Yun, Jeanho

    2017-01-01

    Mitophagy is a process of selective removal of damaged or unnecessary mitochondria using autophagic machinery. Mitophagy plays an essential role in maintaining mitochondrial quality control and homeostasis. Mitochondrial dysfunctions and defective mitophagy in neurodegenerative diseases, cancer, and metabolic diseases indicate a close link between human disease and mitophagy. Furthermore, recent studies showing the involvement of mitophagy in differentiation and development, suggest that mito...

  17. SUMO-regulated mitochondrial function in Parkinson's disease.

    Science.gov (United States)

    Guerra de Souza, Ana Cristina; Prediger, Rui Daniel; Cimarosti, Helena

    2016-06-01

    Parkinson's disease (PD) is the second most common neurodegenerative disorder characterized by cardinal motor signs such as rigidity, bradykinesia or rest tremor that arise from a significant death of dopaminergic neurons. Non-dopaminergic degeneration also occurs and it seems to induce the deficits in olfactory, emotional, and memory functions that precede the classical motor symptoms in PD. Despite the majority of PD cases being sporadic, several genes have previously been associated with the hereditary forms of the disease. The proteins encoded by some of these genes, including α-synuclein, DJ-1, and parkin, are modified by small ubiquitin-like modifier (SUMO), a post-translational modification that regulates a variety of cellular processes. Among the several pathogenic mechanisms proposed for PD is mitochondrial dysfunction. Recent studies suggest that SUMOylation can interfere with mitochondrial dynamics, which is essential for neuronal function, and may play a pivotal role in PD pathogenesis. Here, we present an overview of recent studies on mitochondrial disturbance in PD and the potential SUMO-modified proteins and pathways involved in this process. SUMOylation, a post-translational modification, interferes with mitochondrial dynamics, and may play a pivotal role in Parkinson's disease (PD). SUMOylation maintains α-synuclein (α-syn) in a soluble form and activates DJ-1, decreasing mitochondrial oxidative stress. SUMOylation may reduce the amount of parkin available for mitochondrial recruitment and decreases mitochondrial biogenesis through suppression of peroxisomal proliferator-activated receptor-γ co-activator 1 α (PGC-1α). Mitochondrial fission can be regulated by dynamin-related protein 1 SUMO-1- or SUMO-2/3-ylation. A fine balance for the SUMOylation/deSUMOylation of these proteins is required to ensure adequate mitochondrial function in PD. © 2016 International Society for Neurochemistry.

  18. A mitochondrial etiology of Alzheimer and Parkinson disease.

    Science.gov (United States)

    Coskun, Pinar; Wyrembak, Joanne; Schriner, Samual E; Chen, Hsiao-Wen; Marciniack, Christine; Laferla, Frank; Wallace, Douglas C

    2012-05-01

    The genetics and pathophysiology of Alzheimer Disease (AD) and Parkinson Disease (PD) appears complex. However, mitochondrial dysfunction is a common observation in these and other neurodegenerative diseases. We argue that the available data on AD and PD can be incorporated into a single integrated paradigm based on mitochondrial genetics and pathophysiology. Rare chromosomal cases of AD and PD can be interpreted as affecting mitochondrial function, quality control, and mitochondrial DNA (mtDNA) integrity. mtDNA lineages, haplogroups, such haplogroup H5a which harbors the mtDNA tRNA(Gln) A8336G variant, are important risk factors for AD and PD. Somatic mtDNA mutations are elevated in AD, PD, and Down Syndrome and Dementia (DSAD) both in brains and also systemically. AD, DS, and DSAD brains also have reduced mtDNA ND6 mRNA levels, altered mtDNA copy number, and perturbed Aβ metabolism. Classical AD genetic changes incorporated into the 3XTg-AD (APP, Tau, PS1) mouse result in reduced forebrain size, life-long reduced mitochondrial respiration in 3XTg-AD males, and initially elevated respiration and complex I and IV activities in 3XTg-AD females which markedly declines with age. Therefore, mitochondrial dysfunction provides a unifying genetic and pathophysiology explanation for AD, PD, and other neurodegenerative diseases. This article is part of a Special Issue entitled Biochemistry of Mitochondria. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Toward the Standardization of Mitochondrial Proteomics: The Italian Mitochondrial Human Proteome Project Initiative.

    Science.gov (United States)

    Alberio, Tiziana; Pieroni, Luisa; Ronci, Maurizio; Banfi, Cristina; Bongarzone, Italia; Bottoni, Patrizia; Brioschi, Maura; Caterino, Marianna; Chinello, Clizia; Cormio, Antonella; Cozzolino, Flora; Cunsolo, Vincenzo; Fontana, Simona; Garavaglia, Barbara; Giusti, Laura; Greco, Viviana; Lucacchini, Antonio; Maffioli, Elisa; Magni, Fulvio; Monteleone, Francesca; Monti, Maria; Monti, Valentina; Musicco, Clara; Petrosillo, Giuseppe; Porcelli, Vito; Saletti, Rosaria; Scatena, Roberto; Soggiu, Alessio; Tedeschi, Gabriella; Zilocchi, Mara; Roncada, Paola; Urbani, Andrea; Fasano, Mauro

    2017-12-01

    The Mitochondrial Human Proteome Project aims at understanding the function of the mitochondrial proteome and its crosstalk with the proteome of other organelles. Being able to choose a suitable and validated enrichment protocol of functional mitochondria, based on the specific needs of the downstream proteomics analysis, would greatly help the researchers in the field. Mitochondrial fractions from ten model cell lines were prepared using three enrichment protocols and analyzed on seven different LC-MS/MS platforms. All data were processed using neXtProt as reference database. The data are available for the Human Proteome Project purposes through the ProteomeXchange Consortium with the identifier PXD007053. The processed data sets were analyzed using a suite of R routines to perform a statistical analysis and to retrieve subcellular and submitochondrial localizations. Although the overall number of identified total and mitochondrial proteins was not significantly dependent on the enrichment protocol, specific line to line differences were observed. Moreover, the protein lists were mapped to a network representing the functional mitochondrial proteome, encompassing mitochondrial proteins and their first interactors. More than 80% of the identified proteins resulted in nodes of this network but with a different ability in coisolating mitochondria-associated structures for each enrichment protocol/cell line pair.

  20. Mitochondrial drug delivery and mitochondrial disease therapy--an approach to liposome-based delivery targeted to mitochondria.

    OpenAIRE

    Yamada, Yuma; Akita, Hidetaka; Kogure, Kentaro; Kamiya, Hiroyuki; Harashima, Hideyoshi

    2007-01-01

    Recent progress in genetics and molecular biology has provided useful information regarding the molecular mechanisms associated with the mitochondrial diseases. Genetic approaches were initiated in the late 1980s to clarify the gene responsible for various mitochondrial diseases, and information concerning genetic mutations is currently used in the diagnosis of mitochondrial diseases. Moreover, it was also revealed that mitochondria play a central role in apoptosis, or programmed cell death, ...

  1. Erythropoietin treatment enhances muscle mitochondrial capacity in humans

    DEFF Research Database (Denmark)

    Plenge, Ulla; Belhage, Bo; Guadalupe-Grau, Amelia

    2012-01-01

    Erythropoietin (Epo) treatment has been shown to induce mitochondrial biogenesis in cardiac muscle along with enhanced mitochondrial capacity in mice. We hypothesized that recombinant human Epo (rhEpo) treatment enhances skeletal muscle mitochondrial oxidative phosphorylation (OXPHOS) capacity...... in humans. In six healthy volunteers rhEpo was administered by sub-cutaneous injection over 8 weeks with oral iron (100 mg) supplementation taken daily. Mitochondrial OXPHOS was quantified by high-resolution respirometry in saponin-permeabilized muscle fibers obtained from biopsies of the vastus lateralis....... rhEpo treatment increased OXPHOS (from 92 ± 5 to 113 ± 7 pmol·s(-1)·mg(-1)) and ETS (107 ± 4 to 143 ± 14 pmol·s(-1)·mg(-1), p muscle....

  2. Stimulated human mast cells secrete mitochondrial components that have autocrine and paracrine inflammatory actions.

    Directory of Open Access Journals (Sweden)

    Bodi Zhang

    Full Text Available Mast cells are hematopoietically-derived tissue immune cells that participate in acquired and innate immunity, as well as in inflammation through release of many chemokines and cytokines, especially in response to the pro-inflammatory peptide substance P (SP. Inflammation is critical in the pathogenesis of many diseases, but the trigger(s is often unknown. We investigated if mast cell stimulation leads to secretion of mitochondrial components and whether these could elicit autocrine and/or paracrine inflammatory effects. Here we show that human LAD2 mast cells stimulated by IgE/anti-IgE or by the SP led to secretion of mitochondrial particles, mitochondrial (mt mtDNA and ATP without cell death. Mitochondria purified from LAD2 cells and, when mitochondria added to mast cells trigger degranulation and release of histamine, PGD(2, IL-8, TNF, and IL-1β. This stimulatory effect is partially inhibited by an ATP receptor antagonist and by DNAse. These results suggest that the mitochondrial protein fraction may also contribute. Purified mitochondria also stimulate IL-8 and vascular endothelial growth factor (VEGF release from cultured human keratinocytes, and VEGF release from primary human microvascular endothelial cells. In order to investigate if mitochondrial components could be secreted in vivo, we injected rats intraperiotoneally (ip with compound 48/80, which mimicks the action of SP. Peritoneal mast cells degranulated and mitochondrial particles were documented by transimission electron microscopy outside the cells. We also wished to investigate if mitochondrial components secreted locally could reach the systemic circulation. Administration ip of mtDNA isolated from LAD2 cells in rats was detected in their serum within 4 hr, indicating that extravascular mtDNA could enter the systemic circulation. Secretion of mitochondrial components from stimulated live mast cells may act as "autopathogens" contributing to the pathogenesis of inflammatory

  3. Fatigue and exercise intolerance in mitochondrial diseases. Literature revision and experience of the Italian Network of mitochondrial diseases

    Science.gov (United States)

    Mancuso, M.; Angelini, C.; Bertini, E.; Carelli, V.; Comi, G.P.; Minetti, C.; Moggio, M.; Mongini, T.; Servidei, S.; Tonin, P.; Toscano, A.; Uziel, G.; Zeviani, M.; Siciliano, G.

    2012-01-01

    Fatigue and exercise intolerance are common symptoms of mitochondrial diseases, but difficult to be clinically assessed. New methods to quantify these rather common complaints are strongly needed in the clinical practice. Coenzyme Q10 administration and aerobic exercise may improve exercise intolerance, but more definite studies are still pending. Herein, we have revised “how to measure” and “how to treat” these symptoms of mitochondrial patients. Subsequently, we reviewed the clinical data of the 1164 confirmed mitochondrial patients present in the Italian nation-wide database of mitochondrial disease, with special regard to exercise intolerance. We observed that more of 20% of mitochondrial patients complain of exercise intolerance. This symptom seems to be frequently associated with specific patient groups and/or genotypes. Ragged red fibers and COX-negative fibers are more often present in subjects with exercise intolerance, whereas lactate levels could not predict this symptom. Multicenter efforts are strongly needed for rare disorders such as mitochondrial diseases, and may represent the basis for more rigorous longitudinal studies. PMID:23182644

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

    Science.gov (United States)

    Nicholas, Dequina; Proctor, Elizabeth A; Raval, Forum M; Ip, Blanche C; Habib, Chloe; Ritou, Eleni; Grammatopoulos, Tom N; Steenkamp, Devin; Dooms, Hans; Apovian, Caroline M; Lauffenburger, Douglas A; Nikolajczyk, Barbara S

    2017-01-01

    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.

  5. Mitochondrial dysfunction and human immunodeficiency virus ...

    African Journals Online (AJOL)

    2011-05-04

    May 4, 2011 ... factors. Aids 2002;16(10):1341-1349. 63. John M, Moore CB, James IR, et al. Chronic hyperlactatemia in HIV-infected patients taking antiretroviral therapy. Aids 2001;15(6):717-723. 64. Henry K, Erice A, Balfour HH, Jr., et al. Lymphocyte mitochondrial biomarkers in asymptomatic HIV-1-infected individuals ...

  6. Mitochondrial dysfunction and human immunodeficiency virus ...

    African Journals Online (AJOL)

    Journal of Endocrinology, Metabolism and Diabetes of South Africa ... This review describes the basic physiology, pharmacology and pathophysiology of HIV infection and the nucleoside analogues regarding mitochondrial function and discusses the progress made in this field with respect to the measurement of these ...

  7. 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

  8. Revisiting Mitochondrial Function and Metabolism in Pluripotent Stem Cells: Where Do We Stand in Neurological Diseases?

    Science.gov (United States)

    Lopes, Carla; Rego, A Cristina

    2017-04-01

    Pluripotent stem cells (PSCs) are powerful cellular tools that can generate all the different cell types of the body, and thus overcome the often limited access to human disease tissues; this becomes highly relevant when aiming to investigate cellular (dys)function in diseases affecting the central nervous system. Recent studies have demonstrated that PSC and differentiated cells show altered mitochondrial function and metabolic profiles and production of reactive oxygen species. This raises an emerging paradigm about the role of mitochondria in stem cell biology and urges the need to identify mitochondrial pathways involved in these processes. In this respect, this review focuses on the metabolic profile of PSC and how mitochondrial function can influence the reprogramming and differentiation processes. Indeed, both embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) favor the glycolytic pathway as a major source of energy production over oxidative phosphorylation. PSC mitochondria are characterized by a spherical shape, low copy number of mitochondrial DNA, and a hyperpolarized state. Indeed, mitochondria appear to have a crucial role in reprogramming iPSC, in the maintenance of a pluripotent state, and in differentiation. Moreover, an increase in mitochondrial oxidative phosphorylation has to occur for differentiation to succeed. Therefore, in vitro differentiation of neural stem cells (NSCs) into neurons can be compromised if those mechanisms are impaired. Future research should shed light on how mitochondrial impairment occurring in pre differentiation neural stages (e.g., in NSC or premature neurons) may contribute for the etiopathogenesis of neurodevelopmental and neurological disorders.

  9. Integrated genomic analysis of mitochondrial RNA processing in human cancers.

    Science.gov (United States)

    Idaghdour, Youssef; Hodgkinson, Alan

    2017-04-18

    The mitochondrial genome is transcribed as continuous polycistrons of RNA containing multiple genes. As a consequence, post-transcriptional events are critical for the regulation of gene expression and therefore all aspects of mitochondrial function. One particularly important process is the m1A/m1G RNA methylation of the ninth position of different mitochondrial tRNAs, which allows efficient processing of mitochondrial mRNAs and protein translation, and de-regulation of genes involved in these processes has been associated with altered mitochondrial function. Although mitochondria play a key role in cancer, the status of mitochondrial RNA processing in tumorigenesis is unknown. We measure and assess mitochondrial RNA processing using integrated genomic analysis of RNA sequencing and genotyping data from 1226 samples across 12 different cancer types. We focus on the levels of m1A and m1G RNA methylation in mitochondrial tRNAs in normal and tumor samples and use supervised and unsupervised statistical analysis to compare the levels of these modifications to patient whole genome genotypes, nuclear gene expression, and survival outcomes. We find significant changes to m1A and m1G RNA methylation levels in mitochondrial tRNAs in tumor tissues across all cancers. Pathways of RNA processing are strongly associated with methylation levels in normal tissues (P = 3.27 × 10-31), yet these associations are lost in tumors. Furthermore, we report 18 gene-by-disease-state interactions where altered RNA methylation levels occur under cancer status conditional on genotype, implicating genes associated with mitochondrial function or cancer (e.g., CACNA2D2, LMO2, and FLT3) and suggesting that nuclear genetic variation can potentially modulate an individual's ability to maintain unaltered rates of mitochondrial RNA processing under cancer status. Finally, we report a significant association between the magnitude of methylation level changes in tumors and patient survival

  10. Seizure semiology and EEG findings in mitochondrial diseases.

    Science.gov (United States)

    Chevallier, Justyna A; Von Allmen, Gretchen K; Koenig, Mary Kay

    2014-05-01

    Seizures constitute a frequent yet under-described manifestation of mitochondrial disorders (MDs). The aim of this study was to describe electroencephalography (EEG) findings and clinical seizure types in a population of children and adults with mitochondrial disease. Retrospective chart review of 165 records of children and adults with mitochondrial disease seen in the University of Texas Houston Mitochondrial Center between 2007 and 2012 was performed; all subjects were diagnosed with confirmed mitochondrial disease. EEG findings and clinical data, including seizure semiology and response to antiepileptic drugs (AEDs), were analyzed and categorized. Sixty-six percent (109/165) of subjects had a routine EEG performed. Sixty-one percent (67/109) of EEG studies were abnormal and 85% (56/67) had epileptiform discharges. The most common EEG finding was generalized slowing (40/67, 60%). The most frequent category of epileptiform activity seen was multifocal discharges (41%), followed by focal (39%) and generalized (39%) discharges. Clinical seizures were seen in 55% of subjects and the most common types of seizures observed were complex partial (37%) and generalized tonic-clonic (GTC; 37%). The most common seizure type in patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) was GTC (33%), with generalized or focal discharges seen on EEG. In Leigh syndrome GTC (11%) and complex partial (11%) seizures were the most frequent types. Of 60 subjects with clinical seizures, 28% were intractable to medical treatment. Mitochondrial disorder should be included in the list of differential diagnosis in any child that presents with encephalopathy, seizures, and a fluctuating clinical course. Given the relatively high prevalence of EEG abnormalities in patients with MD, EEG should be performed during initial evaluation in all patients with MD, not only upon clinical suspicion of epilepsy. Wiley Periodicals, Inc. © 2014 International

  11. Mitochondrial Aspects of Synaptic Dysfunction in Alzheimer’s Disease

    Science.gov (United States)

    Cai, Qian; Tammineni, Prasad

    2016-01-01

    Alzheimer’s disease (AD) is characterized by brain deposition of amyloid plaques and tau neurofibrillary tangles along with steady cognitive decline. Synaptic damage, an early pathological event, correlates strongly with cognitive deficits and memory loss. Mitochondria are essential organelles for synaptic function. Neurons utilize specialized mechanisms to drive mitochondrial trafficking to synapses in which mitochondria buffer Ca2+ and serve as local energy sources by supplying ATP to sustain neurotransmitter release. Mitochondrial abnormalities are one of the earliest and prominent features in AD patient brains. Amyloid-β (Aβ) and tau both trigger mitochondrial alterations. Accumulating evidence suggests that mitochondrial perturbation acts as a key factor that is involved in synaptic failure and degeneration in AD. The importance of mitochondria in supporting synaptic function has made them a promising target of new therapeutic strategy for AD. Here, we review the molecular mechanisms regulating mitochondrial function at synapses, highlight recent findings on the disturbance of mitochondrial dynamics and transport in AD, and discuss how these alterations impact synaptic vesicle release and thus contribute to synaptic pathology associated with AD. PMID:27767992

  12. Ketogenic diets: from cancer to mitochondrial diseases and beyond.

    Science.gov (United States)

    Branco, Ana F; Ferreira, André; Simões, Rui F; Magalhães-Novais, Sílvia; Zehowski, Cheryl; Cope, Elisabeth; Silva, Ana Marta; Pereira, Daniela; Sardão, Vilma A; Cunha-Oliveira, Teresa

    2016-03-01

    The employment of dietary strategies such as ketogenic diets, which force cells to alter their energy source, has shown efficacy in the treatment of several diseases. Ketogenic diets are composed of high fat, moderate protein and low carbohydrates, which favour mitochondrial respiration rather than glycolysis for energy metabolism. This review focuses on how oncological, neurological and mitochondrial disorders have been targeted by ketogenic diets, their metabolic effects, and the possible mechanisms of action on mitochondrial energy homeostasis. The beneficial and adverse effects of the ketogenic diets are also highlighted. Although the full mechanism by which ketogenic diets improve oncological and neurological conditions still remains to be elucidated, their clinical efficacy has attracted many new followers, and ketogenic diets can be a good option as a co-adjuvant therapy, depending on the situation and the extent of the disease. © 2016 Stichting European Society for Clinical Investigation Journal Foundation.

  13. Mitochondrial disease in adults: what's old and what's new?

    Science.gov (United States)

    Chinnery, Patrick F

    2015-12-01

    Ten years ago, there was an emerging view that the molecular basis for adult mitochondrial disorders was largely known and that the clinical phenotypes had been well described. Nothing could have been further from the truth. The establishment of large cohorts of patients has revealed new aspects of the clinical presentation that were not previously appreciated. Over time, this approach is starting to provide an accurate understanding of the natural history of mitochondrial disease in adults. Advances in molecular diagnostics, underpinned by next generation sequencing technology, have identified novel molecular mechanisms. Recently described mitochondrial disease phenotypes have disparate causes, and yet share common mechanistic themes. In particular, disorders of mtDNA maintenance have emerged as a major cause of mitochondrial disease in adults. Progressive mtDNA depletion and the accumulation of mtDNA mutations explain some of the clinical features, but the genetic and cellular processes responsible for the mtDNA abnormalities are not entirely clear in each instance. Unfortunately, apart from a few specific examples, treatments for adult mitochondrial disease have not been forthcoming. However, the establishment of international consortia, and the first multinational randomised controlled trial, have paved the way for major progress in the near future, underpinned by growing interest from the pharmaceutical industry. Adult mitochondrial medicine is, therefore, in its infancy, and the challenge is to harness the new understanding of its molecular and cellular basis to develop treatments of real benefit to patients. © 2015 The Author. Published under the terms of the CC BY 4.0 license.

  14. Mitochondrial-Targeted Molecular Imaging in Cardiac Disease

    Directory of Open Access Journals (Sweden)

    Jinhui Li

    2017-01-01

    Full Text Available The present study aimed to discuss the role of mitochondrion in cardiac function and disease. The mitochondrion plays a fundamental role in cellular processes ranging from metabolism to apoptosis. The mitochondrial-targeted molecular imaging could potentially illustrate changes in global and regional cardiac dysfunction. The collective changes that occur in mitochondrial-targeted molecular imaging probes have been widely explored and developed. As probes currently used in the preclinical setting still have a lot of shortcomings, the development of myocardial metabolic activity, viability, perfusion, and blood flow molecular imaging probes holds great potential for accurately evaluating the myocardial viability and functional reserve. The advantages of molecular imaging provide a perspective on investigating the mitochondrial function of the myocardium in vivo noninvasively and quantitatively. The molecular imaging tracers of single-photon emission computed tomography and positron emission tomography could give more detailed information on myocardial metabolism and restoration. In this study, series mitochondrial-targeted 99mTc-, 123I-, and 18F-labeled tracers displayed broad applications because they could provide a direct link between mitochondrial dysfunction and cardiac disease.

  15. Distribution patterns of postmortem damage in human mitochondrial DNA

    DEFF Research Database (Denmark)

    Gilbert, M Thomas P; Willerslev, Eske; Hansen, Anders J

    2002-01-01

    The distribution of postmortem damage in mitochondrial DNA retrieved from 37 ancient human DNA samples was analyzed by cloning and was compared with a selection of published animal data. A relative rate of damage (rho(v)) was calculated for nucleotide positions within the human hypervariable region......, such as MT5, have lower in vivo mutation rates and lower postmortem-damage rates. The postmortem data also identify a possible functional subregion of the HVR1, termed "low-diversity 1," through the lack of sequence damage. The amount of postmortem damage observed in mitochondrial coding regions...

  16. New treatments for mitochondrial disease-no time to drop our standards.

    NARCIS (Netherlands)

    Pfeffer, G.; Horvath, R.; Klopstock, T.; Mootha, V.K.; Suomalainen, A.; Koene, S.; Hirano, M.; Zeviani, M.; Bindoff, L.A.; Yu-Wai-Man, P.; Hanna, M.; Carelli, V.; McFarland, R.; Majamaa, K.; Turnbull, D.M.; Smeitink, J.; Chinnery, P.F.

    2013-01-01

    Mitochondrial dysfunction is a common cause of inherited multisystem disease that often involves the nervous system. Despite major advances in our understanding of the pathophysiology of mitochondrial diseases, clinical management of these conditions remains largely supportive. Using a systematic

  17. Teaching Mitochondrial Genetics & Disease: A GENA Project Curriculum Intervention

    Science.gov (United States)

    Reardon, Ryan A.; Sharer, J. Daniel

    2012-01-01

    This report describes a novel, inquiry-based learning plan developed as part of the GENA educational outreach project. Focusing on mitochondrial genetics and disease, this interactive approach utilizes pedigree analysis and laboratory techniques to address non-Mendelian inheritance. The plan can be modified to fit a variety of educational goals…

  18. Mitochondrial alterations in children with chronic liver disease

    African Journals Online (AJOL)

    Rabah M. Shawky

    Methods: This study was conducted on 26 children and adolescents with chronic liver disease who presented to or were following up .... tion and mitochondrial DNA-PCR assessment of the three groups were tabulated and statistically analyzed using personal computer with SPSS software package. We used repeated mea-.

  19. Immunocytochemical localization of the translocase of the outer mitochondrial membrane (Tom20) in the human cochlea.

    Science.gov (United States)

    Balaker, Ashley E; Ishiyama, Paul; Lopez, Ivan A; Ishiyama, Gail; Ishiyama, Akira

    2013-02-01

    Mitochondrial degeneration in the inner ear is likely a contributing factor in age-related hearing loss and other otopathologies such as Meniere's disease. Most mitochondrial proteins are synthesized in the cytosol and imported through the mitochondrial membranes by translocators. The translocase of the outer membrane (Tom) is the universal entry gate for all proteins that are imported into mitochondria. Altered function of the translocator could alter protein transport into the mitochondria, and disrupt function. In this study, we determined the immunolocalization of Tom20, a major mitochondrial protein import receptor, in microdissected human cochlea frozen sections obtained from postmortem autopsy and celloidin-embedded archival specimens. We used affinity purified rabbit polyclonal antibodies against Tom20. We also determined the Tom20 immunolocalization in the mouse inner ear. In the human and mouse cochlea, Tom20 was ubiquitously distributed in the organ of Corti, allowing well-delineated visualization of inner and outer hair cells. Tom20 immunoreactivity localized in the cytoplasm of spiral ganglia neurons. In the inner ear of aged subjects with Meniere's disease, there was decreased expression of Tom20. These results suggest that Tom20 can be used in the inner ear as a marker for mitochondrial protein import. Copyright © 2012 Wiley Periodicals, Inc.

  20. Immortalized Parkinson's disease lymphocytes have enhanced mitochondrial respiratory activity

    Directory of Open Access Journals (Sweden)

    Sarah J. Annesley

    2016-11-01

    Full Text Available In combination with studies of post-mortem Parkinson's disease (PD brains, pharmacological and genetic models of PD have suggested that two fundamental interacting cellular processes are impaired – proteostasis and mitochondrial respiration. We have re-examined the role of mitochondrial dysfunction in lymphoblasts isolated from individuals with idiopathic PD and an age-matched control group. As previously reported for various PD cell types, the production of reactive oxygen species (ROS by PD lymphoblasts was significantly elevated. However, this was not due to an impairment of mitochondrial respiration, as is often assumed. Instead, basal mitochondrial respiration and ATP synthesis are dramatically elevated in PD lymphoblasts. The mitochondrial mass, genome copy number and membrane potential were unaltered, but the expression of indicative respiratory complex proteins was also elevated. This explains the increased oxygen consumption rates by each of the respiratory complexes in experimentally uncoupled mitochondria of iPD cells. However, it was not attributable to increased activity of the stress- and energy-sensing protein kinase AMPK, a regulator of mitochondrial biogenesis and activity. The respiratory differences between iPD and control cells were sufficiently dramatic as to provide a potentially sensitive and reliable biomarker of the disease state, unaffected by disease duration (time since diagnosis or clinical severity. Lymphoblasts from control and PD individuals thus occupy two distinct, quasi-stable steady states; a ‘normal’ and a ‘hyperactive’ state characterized by two different metabolic rates. The apparent stability of the ‘hyperactive’ state in patient-derived lymphoblasts in the face of patient ageing, ongoing disease and mounting disease severity suggests an early, permanent switch to an alternative metabolic steady state. With its associated, elevated ROS production, the ‘hyperactive’ state might not cause

  1. Audiological evaluation in mitochondrial disease: two case report

    OpenAIRE

    Silveira, Marcela Rosana Maia da; Gil, Daniela

    2008-01-01

    BACKGROUND: hearing and mitochondriopathy. PROCEDURE: this case report aims at describing audiological evaluation results of two children diagnosed with mitochondrial disease referred to Clinical Audiology Out-patient Clinic of UNIFESP/EPM. Children were referred to audiology department from metabolic diseases out-patient clinic of UNIFESP. Both have undergone pure tone audiometry, behavioral observation, immittance measures and otoacoustic emissions. RESULTS: either behavioral or physiologic...

  2. Mitochondrial dysfunction in a transgenic mouse model expressing human amyloid precursor protein (APP) with the Arctic mutation.

    Science.gov (United States)

    Rönnbäck, Annica; Pavlov, Pavel F; Mansory, Mansorah; Gonze, Prisca; Marlière, Nicolas; Winblad, Bengt; Graff, Caroline; Behbahani, Homira

    2016-02-01

    Accumulation of amyloid β-peptide (Aβ) in the brain is an important event in the pathogenesis of Alzheimer disease. We have used a transgenic mouse model expressing human amyloid precursor protein (APP) with the Arctic mutation to investigate whether Aβ deposition is correlated with mitochondrial functions in these animals. We found evidence of mitochondrial dysfunction (i.e., decreased mitochondrial membrane potential, increased production of reactive oxygen species and oxidative DNA damage) at 6 months of age, when the mice showed very mild Aβ deposition. More pronounced mitochondrial abnormalities were present in 24-month-old TgAPParc mice with more extensive Aβ pathology. This study demonstrates for the first time mitochondrial dysfunction in transgenic mice with a mutation within the Aβ peptide (the Arctic APP mutation), and confirms previous studies suggesting that mitochondrial dysfunction and oxidative stress is an early event in the pathogenesis of Alzheimer disease. This study demonstrates mitochondrial dysfunction in transgenic mice with a mutation within the amyloid beta (Aβ) peptide (the Arctic amyloid precursor protein (APP) mutation). We found evidence of mitochondrial dysfunction (i.e. decreased mitochondrial membrane potential (MMP), increased production of reactive oxygen species (ROS) and oxidative DNA damage) at 6 months of age, when very mild Aβ deposition is present in the mice. Also, the cytochrome c (COX) activity was significantly decreased in mitochondria from transgenic mice at 24 months of age. © 2015 International Society for Neurochemistry.

  3. mtDB: Human Mitochondrial Genome Database, a resource for population genetics and medical sciences

    National Research Council Canada - National Science Library

    Ingman, Max; Gyllensten, Ulf

    2006-01-01

    ..., as well as for population genetics studies. Human Mitochondrial Genome Database (mtDB) (http://www.genpat.uu.se/mtDB) has provided a comprehensive database of complete human mitochondrial genomes since early 2000...

  4. Synaptosomal Mitochondrial Dysfunction in 5xFAD Mouse Model of Alzheimer's Disease.

    Directory of Open Access Journals (Sweden)

    Lu Wang

    Full Text Available Brain mitochondrial dysfunction is hallmark pathology of Alzheimer's disease (AD. Recently, the role of synaptosomal mitochondrial dysfunction in the development of synaptic injury in AD has received increasing attention. Synaptosomal mitochondria are a subgroup of neuronal mitochondria specifically locating at synapses. They play an essential role in fueling synaptic functions by providing energy on the site; and their defects may lead to synaptic failure, which is an early and pronounced pathology in AD. In our previous studies we have determined early synaptosomal mitochondrial dysfunction in an AD animal model (J20 line overexpressing human Amyloid beta (Aβ, the key mediator of AD. In view of the limitations of J20 line mice in representing the full aspects of amyloidopathy in AD cases, we employed 5xFAD mice which are thought to be a desirable paradigm of amyloidopathy as seen in AD subjects. In addition, we have also examined the status of synaptosomal mitochondrial dynamics as well as Parkin-mediated mitophagy which have not been previously investigated in this mouse model. In comparison to nontransgenic (nonTg mice, 5xFAD mice demonstrated prominent synaptosomal mitochondrial dysfunction. Moreover, synaptosomal mitochondria from the AD mouse model displayed imbalanced mitochondrial dynamics towards fission along with activated Parkin and LC3BII recruitment correlating to spatial learning & memory impairments in 5xFAD mice in an age-dependent manner. These results suggest that synaptosomal mitochondrial deficits are primary pathology in Aβ-rich environments and further confirm the relevance of synaptosomal mitochondrial deficits to the development of AD.

  5. Synaptosomal Mitochondrial Dysfunction in 5xFAD Mouse Model of Alzheimer's Disease.

    Science.gov (United States)

    Wang, Lu; Guo, Lan; Lu, Lin; Sun, Huili; Shao, Muming; Beck, Simon J; Li, Lin; Ramachandran, Janani; Du, Yifeng; Du, Heng

    2016-01-01

    Brain mitochondrial dysfunction is hallmark pathology of Alzheimer's disease (AD). Recently, the role of synaptosomal mitochondrial dysfunction in the development of synaptic injury in AD has received increasing attention. Synaptosomal mitochondria are a subgroup of neuronal mitochondria specifically locating at synapses. They play an essential role in fueling synaptic functions by providing energy on the site; and their defects may lead to synaptic failure, which is an early and pronounced pathology in AD. In our previous studies we have determined early synaptosomal mitochondrial dysfunction in an AD animal model (J20 line) overexpressing human Amyloid beta (Aβ), the key mediator of AD. In view of the limitations of J20 line mice in representing the full aspects of amyloidopathy in AD cases, we employed 5xFAD mice which are thought to be a desirable paradigm of amyloidopathy as seen in AD subjects. In addition, we have also examined the status of synaptosomal mitochondrial dynamics as well as Parkin-mediated mitophagy which have not been previously investigated in this mouse model. In comparison to nontransgenic (nonTg mice), 5xFAD mice demonstrated prominent synaptosomal mitochondrial dysfunction. Moreover, synaptosomal mitochondria from the AD mouse model displayed imbalanced mitochondrial dynamics towards fission along with activated Parkin and LC3BII recruitment correlating to spatial learning & memory impairments in 5xFAD mice in an age-dependent manner. These results suggest that synaptosomal mitochondrial deficits are primary pathology in Aβ-rich environments and further confirm the relevance of synaptosomal mitochondrial deficits to the development of AD.

  6. Markov chain for estimating human mitochondrial DNA mutation pattern

    Science.gov (United States)

    Vantika, Sandy; Pasaribu, Udjianna S.

    2015-12-01

    The Markov chain was proposed to estimate the human mitochondrial DNA mutation pattern. One DNA sequence was taken randomly from 100 sequences in Genbank. The nucleotide transition matrix and mutation transition matrix were estimated from this sequence. We determined whether the states (mutation/normal) are recurrent or transient. The results showed that both of them are recurrent.

  7. Maternal inheritance and mitochondrial DNA variants in familial Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Pfeiffer Ronald F

    2010-04-01

    Full Text Available Abstract Background Mitochondrial function is impaired in Parkinson's disease (PD and may contribute to the pathogenesis of PD, but the causes of mitochondrial impairment in PD are unknown. Mitochondrial dysfunction is recapitulated in cell lines expressing mitochondrial DNA (mtDNA from PD patients, implicating mtDNA variants or mutations, though the role of mtDNA variants or mutations in PD risk remains unclear. We investigated the potential contribution of mtDNA variants or mutations to the risk of PD. Methods We examined the possibility of a maternal inheritance bias as well as the association between mitochondrial haplogroups and maternal inheritance and disease risk in a case-control study of 168 multiplex PD families in which the proband and one parent were diagnosed with PD. 2-tailed Fisher Exact Tests and McNemar's tests were used to compare allele frequencies, and a t-test to compare ages of onset. Results The frequency of affected mothers of the proband with PD (83/167, 49.4% was not significantly different from the frequency of affected females of the proband generation (115/259, 44.4% (Odds Ratio 1.22; 95%CI 0.83 - 1.81. After correcting for multiple tests, there were no significant differences in the frequencies of mitochondrial haplogroups or of the 10398G complex I gene polymorphism in PD patients compared to controls, and no significant associations with age of onset of PD. Mitochondrial haplogroup and 10398G polymorphism frequencies were similar in probands having an affected father as compared to probands having an affected mother. Conclusions These data fail to demonstrate a bias towards maternal inheritance in familial PD. Consistent with this, we find no association of common haplogroup-defining mtDNA variants or for the 10398G variant with the risk of PD. However, these data do not exclude a role for mtDNA variants in other populations, and it remains possible that other inherited mitochondrial DNA variants, or somatic m

  8. Defects in Mitochondrial Dynamics and Metabolomic Signatures of Evolving Energetic Stress in Mouse Models of Familial Alzheimer's Disease

    Science.gov (United States)

    Trushina, Eugenia; Nemutlu, Emirhan; Zhang, Song; Christensen, Trace; Camp, Jon; Mesa, Janny; Siddiqui, Ammar; Tamura, Yasushi; Sesaki, Hiromi; Wengenack, Thomas M.; Dzeja, Petras P.; Poduslo, Joseph F.

    2012-01-01

    Background The identification of early mechanisms underlying Alzheimer's Disease (AD) and associated biomarkers could advance development of new therapies and improve monitoring and predicting of AD progression. Mitochondrial dysfunction has been suggested to underlie AD pathophysiology, however, no comprehensive study exists that evaluates the effect of different familial AD (FAD) mutations on mitochondrial function, dynamics, and brain energetics. Methods and Findings We characterized early mitochondrial dysfunction and metabolomic signatures of energetic stress in three commonly used transgenic mouse models of FAD. Assessment of mitochondrial motility, distribution, dynamics, morphology, and metabolomic profiling revealed the specific effect of each FAD mutation on the development of mitochondrial stress and dysfunction. Inhibition of mitochondrial trafficking was characteristic for embryonic neurons from mice expressing mutant human presenilin 1, PS1(M146L) and the double mutation of human amyloid precursor protein APP(Tg2576) and PS1(M146L) contributing to the increased susceptibility of neurons to excitotoxic cell death. Significant changes in mitochondrial morphology were detected in APP and APP/PS1 mice. All three FAD models demonstrated a loss of the integrity of synaptic mitochondria and energy production. Metabolomic profiling revealed mutation-specific changes in the levels of metabolites reflecting altered energy metabolism and mitochondrial dysfunction in brains of FAD mice. Metabolic biomarkers adequately reflected gender differences similar to that reported for AD patients and correlated well with the biomarkers currently used for diagnosis in humans. Conclusions Mutation-specific alterations in mitochondrial dynamics, morphology and function in FAD mice occurred prior to the onset of memory and neurological phenotype and before the formation of amyloid deposits. Metabolomic signatures of mitochondrial stress and altered energy metabolism indicated

  9. Lysosomal and Mitochondrial Liaisons in Niemann-Pick Disease

    Directory of Open Access Journals (Sweden)

    Sandra Torres

    2017-11-01

    Full Text Available Lysosomal storage disorders (LSD are characterized by the accumulation of diverse lipid species in lysosomes. Niemann-Pick type A/B (NPA/B and type C diseases Niemann-Pick type C (NPC are progressive LSD caused by loss of function of distinct lysosomal-residing proteins, acid sphingomyelinase and NPC1, respectively. While the primary cause of these diseases differs, both share common biochemical features, including the accumulation of sphingolipids and cholesterol, predominantly in endolysosomes. Besides these alterations in lysosomal homeostasis and function due to accumulation of specific lipid species, the lysosomal functional defects can have far-reaching consequences, disrupting intracellular trafficking of sterols, lipids and calcium through membrane contact sites (MCS of apposed compartments. Although MCS between endoplasmic reticulum and mitochondria have been well studied and characterized in different contexts, emerging evidence indicates that lysosomes also exhibit close proximity with mitochondria, which translates in their mutual functional regulation. Indeed, as best illustrated in NPC disease, alterations in the lysosomal-mitochondrial liaisons underlie the secondary accumulation of specific lipids, such as cholesterol in mitochondria, resulting in mitochondrial dysfunction and defective antioxidant defense, which contribute to disease progression. Thus, a better understanding of the lysosomal and mitochondrial interactions and trafficking may identify novel targets for the treatment of Niemann-Pick disease.

  10. Cyclophilin D deficiency improves mitochondrial function and learning/memory in aging Alzheimer disease mouse model

    OpenAIRE

    Du, Heng; Guo, Lan; Zhang, Wensheng; Rydzewska, Monika; Yan, Shidu

    2009-01-01

    Mitochondrial stress is one of the early features of Alzheimer disease (AD). Mitochondrial Aβ has been linked to mitochondrial toxicity. Our recent study demonstrated that cyclophilin D (CypD) mediated mitochondrial permeability transition pore (mPTP) is an important mechanism for neuronal and synaptic stress induced by both Aβ and oxidative stress. In transgenic AD-type mice overexpressing mutant amyloid precursor protein (APP) and Aβ (mAPP), CypD deficiency improves mitochondrial and synapt...

  11. How rapidly does the human mitochondrial genome evolve?

    Energy Technology Data Exchange (ETDEWEB)

    Howell, N.; Kubacka, I. [Univ. of Texas Medical Branch, Galveston, TX (United States); Mackey, D.A. [Univ. of Melbourne (Australia)]|[Univ. of Tasmania, Launceston (Australia)

    1996-09-01

    The results of an empirical nucleotide-sequencing approach indicate that the evolution of the human mitochondrial noncoding D-loop is both more rapid and more complex than is revealed by standard phylogenetic approaches. The nucleotide sequence of the D-loop region of the mitochondrial genome was determined for 45 members of a large matrilineal Leber hereditary optic neuropathy pedigree. Two germ-line mutations have arisen in members of one branch of the family, thereby leading to triplasmic descendants with three mitochondrial genotypes. Segregation toward the homoplasmic state can occur within a single generation in some of these descendants, a result that suggests rapid fixation of mitochondrial mutations as a result of developmental bottlenecking. However, slow segregation was observed in other offspring, and therefore no single or simple pattern of segregation can be generalized from the available data. Evidence for rare mtDNA recombination within the D-loop was obtained for one family member. In addition to these germ-line mutations, a somatic mutation was found in the D-loop of one family member. When this genealogical approach was applied to the nucleotide sequences of mitochondrial coding regions, the results again indicated a very rapid rate of evolution. 44 refs., 2 figs., 2 tabs.

  12. Manganese induces mitochondrial dynamics impairment and apoptotic cell death: a study in human Gli36 cells.

    Science.gov (United States)

    Alaimo, Agustina; Gorojod, Roxana M; Miglietta, Esteban A; Villarreal, Alejandro; Ramos, Alberto J; Kotler, Mónica L

    2013-10-25

    Manganese (Mn) is an essential trace element due to its participation in many physiological processes. However, overexposure to this metal leads to a neurological disorder known as Manganism whose clinical manifestations and molecular mechanisms resemble Parkinson's disease. Several lines of evidence implicate astrocytes as an early target of Mn neurotoxicity being the mitochondria the most affected organelles. The aim of this study was to investigate the possible mitochondrial dynamics alterations in Mn-exposed human astrocytes. Therefore, we employed Gli36 cells which express the astrocytic markers GFAP and S100B. We demonstrated that Mn triggers the mitochondrial apoptotic pathway revealed by increased Bax/Bcl-2 ratio, by the loss of mitochondrial membrane potential and by caspase-9 activation. This apoptotic program may be in turn responsible of caspase-3/7 activation, PARP-1 cleavage, chromatin condensation and fragmentation. In addition, we determined that Mn induces deregulation in mitochondria-shaping proteins (Opa-1, Mfn-2 and Drp-1) expression levels in parallel with the disruption of the mitochondrial network toward to an exacerbated fragmentation. Since mitochondrial dynamics is altered in several neurodegenerative diseases, these proteins could become future targets to be considered in Manganism treatment. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  13. Activated macrophages control human adipocyte mitochondrial bioenergetics via secreted factors.

    Science.gov (United States)

    Keuper, Michaela; Sachs, Stephan; Walheim, Ellen; Berti, Lucia; Raedle, Bernhard; Tews, Daniel; Fischer-Posovszky, Pamela; Wabitsch, Martin; Hrabě de Angelis, Martin; Kastenmüller, Gabi; Tschöp, Matthias H; Jastroch, Martin; Staiger, Harald; Hofmann, Susanna M

    2017-10-01

    Obesity-associated WAT inflammation is characterized by the accumulation and local activation of macrophages (MΦs), and recent data from mouse studies suggest that macrophages are modifiers of adipocyte energy metabolism and mitochondrial function. As mitochondrial dysfunction has been associated with obesity and the metabolic syndrome in humans, herein we aimed to delineate how human macrophages may affect energy metabolism of white adipocytes. Human adipose tissue gene expression analysis for markers of macrophage activation and tissue inflammation (CD11c, CD40, CD163, CD206, CD80, MCP1, TNFα) in relationship to mitochondrial complex I (NDUFB8) and complex III (UQCRC2) was performed on subcutaneous WAT of 24 women (BMI 20-61 kg/m 2 ). Guided by these results, the impact of secreted factors of LPS/IFNγ- and IL10/TGFβ-activated human macrophages (THP1, primary blood-derived) on mitochondrial function in human subcutaneous white adipocytes (SGBS, primary) was determined by extracellular flux analysis (Seahorse technology) and gene/protein expression. Stepwise regression analysis of human WAT gene expression data revealed that a linear combination of CD40 and CD163 was the strongest predictor for mitochondrial complex I (NDUFB8) and complex III (UQCRC2) levels, independent of BMI. IL10/TGFβ-activated MΦs displayed high CD163 and low CD40 expression and secreted factors that decreased UQCRC2 gene/protein expression and ATP-linked respiration in human white adipocytes. In contrast, LPS/IFNγ-activated MΦs showed high CD40 and low CD163 expression and secreted factors that enhanced adipocyte mitochondrial activity resulting in a total difference of 37% in ATP-linked respiration of white adipocytes (p = 0.0024) when comparing the effect of LPS/IFNγ- vs IL10/TGFβ-activated MΦs. Our data demonstrate that macrophages modulate human adipocyte energy metabolism via an activation-dependent paracrine mechanism. Copyright © 2017 The Authors. Published by Elsevier

  14. Reduced basal autophagy and impaired mitochondrial dynamics due to loss of Parkinson's disease-associated protein DJ-1.

    Directory of Open Access Journals (Sweden)

    Guido Krebiehl

    2010-02-01

    Full Text Available Mitochondrial dysfunction and degradation takes a central role in current paradigms of neurodegeneration in Parkinson's disease (PD. Loss of DJ-1 function is a rare cause of familial PD. Although a critical role of DJ-1 in oxidative stress response and mitochondrial function has been recognized, the effects on mitochondrial dynamics and downstream consequences remain to be determined.Using DJ-1 loss of function cellular models from knockout (KO mice and human carriers of the E64D mutation in the DJ-1 gene we define a novel role of DJ-1 in the integrity of both cellular organelles, mitochondria and lysosomes. We show that loss of DJ-1 caused impaired mitochondrial respiration, increased intramitochondrial reactive oxygen species, reduced mitochondrial membrane potential and characteristic alterations of mitochondrial shape as shown by quantitative morphology. Importantly, ultrastructural imaging and subsequent detailed lysosomal activity analyses revealed reduced basal autophagic degradation and the accumulation of defective mitochondria in DJ-1 KO cells, that was linked with decreased levels of phospho-activated ERK2.We show that loss of DJ-1 leads to impaired autophagy and accumulation of dysfunctional mitochondria that under physiological conditions would be compensated via lysosomal clearance. Our study provides evidence for a critical role of DJ-1 in mitochondrial homeostasis by connecting basal autophagy and mitochondrial integrity in Parkinson's disease.

  15. Parkinson's disease and brain mitochondrial dysfunction: a functional phosphorus magnetic resonance spectroscopy study.

    Science.gov (United States)

    Rango, Mario; Bonifati, Cristiana; Bresolin, Nereo

    2006-02-01

    In spite of several evidences for a mitochondrial impairment in Parkinson's disease (PD), so far it has not been possible to show in vivo mitochondrial dysfunction in the human brain of PD patients. The authors used the high temporal and spatial resolution 31 phosphorus magnetic resonance spectroscopy (31P MRS) technique, which they have previously developed in normal subjects and in patients with mitochondrial diseases to study mitochondrial function by observing high-energy phosphates (HEPs) and intracellular pH (pH) in the visual cortex of 20 patients with PD and 20 normal subjects at rest, during, and after visual activation. In normal subjects, HEPs remained unchanged during activation, but rose significantly (by 16%) during recovery, and pH increased during visual activation with a slow return to rest values. In PD patients, HEPs were within the normal range at rest and did not change during activation, but fell significantly (by 36%) in the recovery period; pH did not reveal a homogeneous pattern with a wide spread of values. Energy unbalance under increased oxidative metabolism requirements, that is, the postactivation phase, discloses a mitochondrial dysfunction that is present in the brain of patients with PD even in the absence of overt clinical manifestations, as in the visual cortex. This is in agreement with our previous findings in patients with mitochondrial disease without clinical central nervous system (CNS) involvement. The heterogeneity of the physicochemical environment (i.e., pH) suggests various degrees of subclinical brain involvement in PD. The combined use of MRS and brain activation is fundamental for the study of brain energetics in patients with PD and may prove an important tool for diagnostic purposes and, possibly, to monitor therapeutic interventions.

  16. Holes influence the mutation spectrum of human mitochondrial DNA

    Science.gov (United States)

    Villagran, Martha; Miller, John

    Mutations drive evolution and disease, showing highly non-random patterns of variant frequency vs. nucleotide position. We use computational DNA hole spectroscopy [M.Y. Suarez-Villagran & J.H. Miller, Sci. Rep. 5, 13571 (2015)] to reveal sites of enhanced hole probability in selected regions of human mitochondrial DNA. A hole is a mobile site of positive charge created when an electron is removed, for example by radiation or contact with a mutagenic agent. The hole spectra are quantum mechanically computed using a two-stranded tight binding model of DNA. We observe significant correlation between spectra of hole probabilities and of genetic variation frequencies from the MITOMAP database. These results suggest that hole-enhanced mutation mechanisms exert a substantial, perhaps dominant, influence on mutation patterns in DNA. One example is where a trapped hole induces a hydrogen bond shift, known as tautomerization, which then triggers a base-pair mismatch during replication. Our results deepen overall understanding of sequence specific mutation rates, encompassing both hotspots and cold spots, which drive molecular evolution.

  17. 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.

  18. 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.

  19. Role of the mitochondrial DNA replication machinery in mitochondrial DNA mutagenesis, aging and age-related diseases.

    Science.gov (United States)

    DeBalsi, Karen L; Hoff, Kirsten E; Copeland, William C

    2017-01-01

    As regulators of bioenergetics in the cell and the primary source of endogenous reactive oxygen species (ROS), dysfunctional mitochondria have been implicated for decades in the process of aging and age-related diseases. Mitochondrial DNA (mtDNA) is replicated and repaired by nuclear-encoded mtDNA polymerase γ (Pol γ) and several other associated proteins, which compose the mtDNA replication machinery. Here, we review evidence that errors caused by this replication machinery and failure to repair these mtDNA errors results in mtDNA mutations. Clonal expansion of mtDNA mutations results in mitochondrial dysfunction, such as decreased electron transport chain (ETC) enzyme activity and impaired cellular respiration. We address the literature that mitochondrial dysfunction, in conjunction with altered mitochondrial dynamics, is a major driving force behind aging and age-related diseases. Additionally, interventions to improve mitochondrial function and attenuate the symptoms of aging are examined. Published by Elsevier B.V.

  20. Autism and Intellectual Disability Associated with Mitochondrial Disease and Hyperlactacidemia

    Directory of Open Access Journals (Sweden)

    José Guevara-Campos

    2015-02-01

    Full Text Available Autism spectrum disorder (ASD with intellectual disability (ID is a life-long debilitating condition, which is characterized by cognitive function impairment and other neurological signs. Children with ASD-ID typically attain motor skills with a significant delay. A sub-group of ASD-IDs has been linked to hyperlactacidemia and alterations in mitochondrial respiratory chain activity. The objective of this report is to describe the clinical features of patients with these comorbidities in order to shed light on difficult diagnostic and therapeutic approaches in such patients. We reported the different clinical features of children with ID associated with hyperlactacidemia and deficiencies in mitochondrial respiratory chain complex II–IV activity whose clinical presentations are commonly associated with the classic spectrum of mitochondrial diseases. We concluded that patients with ASD and ID presenting with persistent hyperlactacidemia should be evaluated for mitochondrial disorders. Administration of carnitine, coenzyme Q10, and folic acid is partially beneficial, although more studies are needed to assess the efficacy of this vitamin/cofactor treatment combination.

  1. Trifloxystrobin-induced mitophagy through mitochondrial damage in human skin keratinocytes.

    Science.gov (United States)

    Jang, Yoonjeong; Kim, Ji-Eun; Jeong, Sang-Hee; Paik, Min-Kyoung; Kim, Jun Sung; Cho, Myung-Haing

    2016-01-01

    Trifloxystrobin is a strobilurin class fungicide, the mode of action of which is to block the mitochondrial electron transport chain and inhibit energy production in fungi. Although adverse effects have been reported by occupational or environmental exposure of fungicides, the pathophysiological mechanism in human cells remains poorly understood. In the present study, we investigated the impact of trifloxystrobin on exposed skin at the cellular organelle level using HaCaT, the human skin keratinocyte cell line. Cells were treated with trifloxystrobin for 48 hr and trifloxystrobin showed detrimental effects on mitochondria evidenced by altered mitochondrial membrane potential and morphology. To identify autophagic degradation of the damaged mitochondria, confocal imaging and Western blotting were performed. Trifloxystrobin induced autophagy-related proteins in HaCaT cells. The mitochondrial reactive oxygen species scavenger mitoTEMPO was applied to further explore the mechanism of trifloxystrobin-mediated mitophagy in human skin cells. PINK1 and Parkin were overexpressed by trifloxystrobin, and mitoTEMPO alleviated the effects on mitophagy induction. Taken together, our findings indicated that mitochondrial damage and mitophagy may play a role in trifloxystrobin-induced toxicity in human keratinocytes and this could be suggested as a mechanism of cutaneous diseases developed by exposure.

  2. Mitochondrial respiratory chain disease presenting as progressive bulbar paralysis of childhood

    NARCIS (Netherlands)

    Roeleveld-Versteegh, ABC; Braun, KPJ; Smeitink, JAM; Dorland, L; de Koning, TJ

    2004-01-01

    We report two siblings with a mitochondrial respiratory chain defect who presented with progressive bulbar paralysis of childhood ( Fazio-Londe disease). Mitochondrial respiratory chain defects should be considered in the differential diagnosis of this rare clinical entity.

  3. Mitochondrial respiratory chain disease presenting as progressive bulbar paralysis of childhood.

    NARCIS (Netherlands)

    Roeleveld-Versteegh, A.B.; Braun, K.P.; Smeitink, J.A.M.; Dorland, L.; Koning, T.J.

    2004-01-01

    We report two siblings with a mitochondrial respiratory chain defect who presented with progressive bulbar paralysis of childhood (Fazio-Londe disease). Mitochondrial respiratory chain defects should be considered in differential diagnosis of this rare clinical entity.

  4. Mitochondrial targeting of recombinant RNAs modulates the level of a heteroplasmic mutation in human mitochondrial DNA associated with Kearns Sayre Syndrome.

    Science.gov (United States)

    Comte, Caroline; Tonin, Yann; Heckel-Mager, Anne-Marie; Boucheham, Abdeldjalil; Smirnov, Alexandre; Auré, Karine; Lombès, Anne; Martin, Robert P; Entelis, Nina; Tarassov, Ivan

    2013-01-07

    Mitochondrial mutations, an important cause of incurable human neuromuscular diseases, are mostly heteroplasmic: mutated mitochondrial DNA is present in cells simultaneously with wild-type genomes, the pathogenic threshold being generally >70% of mutant mtDNA. We studied whether heteroplasmy level could be decreased by specifically designed oligoribonucleotides, targeted into mitochondria by the pathway delivering RNA molecules in vivo. Using mitochondrially imported RNAs as vectors, we demonstrated that oligoribonucleotides complementary to mutant mtDNA region can specifically reduce the proportion of mtDNA bearing a large deletion associated with the Kearns Sayre Syndrome in cultured transmitochondrial cybrid cells. These findings may be relevant to developing of a new tool for therapy of mtDNA associated diseases.

  5. 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.

  6. Disease-associated mitochondrial mutations and the evolution of primate mitogenomes.

    Directory of Open Access Journals (Sweden)

    William Corrêa Tavares

    Full Text Available Several human diseases have been associated with mutations in mitochondrial genes comprising a set of confirmed and reported mutations according to the MITOMAP database. An analysis of complete mitogenomes across 139 primate species showed that most confirmed disease-associated mutations occurred in aligned codon positions and gene regions under strong purifying selection resulting in a strong evolutionary conservation. Only two confirmed variants (7.1%, coding for the same amino acids accounting for severe human diseases, were identified without apparent pathogenicity in non-human primates, like the closely related Bornean orangutan. Conversely, reported disease-associated mutations were not especially concentrated in conserved codon positions, and a large fraction of them occurred in highly variable ones. Additionally, 88 (45.8% of reported mutations showed similar variants in several non-human primates and some of them have been present in extinct species of the genus Homo. Considering that recurrent mutations leading to persistent variants throughout the evolutionary diversification of primates are less likely to be severely damaging to fitness, we suggest that these 88 mutations are less likely to be pathogenic. Conversely, 69 (35.9% of reported disease-associated mutations occurred in extremely conserved aligned codon positions which makes them more likely to damage the primate mitochondrial physiology.

  7. Mitochondrial impairment in microglia amplifies NLRP3 inflammasome proinflammatory signaling in cell culture and animal models of Parkinson's disease.

    Science.gov (United States)

    Sarkar, Souvarish; Malovic, Emir; Harishchandra, Dilshan S; Ghaisas, Shivani; Panicker, Nikhil; Charli, Adhithiya; Palanisamy, Bharathi N; Rokad, Dharmin; Jin, Huajun; Anantharam, Vellareddy; Kanthasamy, Arthi; Kanthasamy, Anumantha G

    2017-01-01

    The NLRP3 inflammasome signaling pathway is a major contributor to the neuroinflammatory process in the central nervous system. Oxidative stress and mitochondrial dysfunction are key pathophysiological processes of many chronic neurodegenerative diseases, including Parkinson's disease (PD). However, the inter-relationship between mitochondrial defects and neuroinflammation is not well understood. In the present study, we show that impaired mitochondrial function can augment the NLRP3 inflammasome-driven proinflammatory cascade in microglia. Primary mouse microglia treated with the common inflammogen LPS increased NLRP3 and pro-IL-1β expression. Interestingly, exposure of LPS-primed microglial cells to the mitochondrial complex-I inhibitory pesticides rotenone and tebufenpyrad specifically potentiated the NLRP3 induction, ASC speck formation and pro-IL-1β processing to IL-1β in a dose-dependent manner, indicating that mitochondrial impairment heightened the NLRP3 inflammasome-mediated proinflammatory response in microglia. The neurotoxic pesticide-induced NLRP3 inflammasome activation was accompanied by bioenergetic defects and lysosomal dysfunction in microglia. Furthermore, the pesticides enhanced mitochondrial ROS generation in primary microglia, while amelioration of mitochondria-derived ROS by the mitochondria-targeted antioxidant mito-apocynin completely abolished IL-1β release, indicating mitochondrial ROS drives potentiation of the NLRP3 inflammasome in microglia. Exposure to conditioned media obtained from mitochondrial inhibitor-treated, LPS-primed microglial cells, but not unprimed cells, induced dopaminergic neurodegeneration in cultured primary mesencephalic and human dopaminergic neuronal cells (LUHMES). Notably, our in vivo results with chronic rotenone rodent models of PD further support the activation of proinflammatory NLRP3 inflammasome signaling due to mitochondrial dysfunction. Collectively, our results demonstrate that mitochondrial

  8. Is mitochondrial tRNA(Ser(UCN)) T7501C mutation associated with cardiovascular disease?

    Science.gov (United States)

    Ding, Yu; Huang, Jinyu

    2016-01-01

    Mitochondrial DNA mutations are increasingly recognized as an important cause of cardiovascular diseases, point mutations in mitochondrial tRNA genes being the largest group among them. Most recently, mutation at position 7501 in mt-tRNA(Ser(UCN)) gene has been reported to be associated with human cardiovascular diseases including cardiomyopathy, sudden cardiac death (SCD) and Tetralogy of Fallot (TOF). However, its direct pathogenic role remained poorly understood. In this study, we performed an extensive web-based search for the published resources concerning this association. Through the application of bioinformatics tool, we observed that this mutation altered the mt-tRNA(Ser(UCN)) secondary structure, in addition, evolutionary conservation analysis of this mutation indicated that this mutation is highly conserved between different species. Notably, the T7501C mutation belonging to human mitochondrial haplogroup U8a1a1, a rare subgroup of U8, was present only in European population and was absent in Han Chinese population. Taken together, our result indicated that the T7501C mutation may occur infrequently and was probably pathogenic in cardiovascular disease development.

  9. Calorie restriction increases muscle mitochondrial biogenesis in healthy humans.

    Directory of Open Access Journals (Sweden)

    Anthony E Civitarese

    2007-03-01

    Full Text Available Caloric restriction without malnutrition extends life span in a range of organisms including insects and mammals and lowers free radical production by the mitochondria. However, the mechanism responsible for this adaptation are poorly understood.The current study was undertaken to examine muscle mitochondrial bioenergetics in response to caloric restriction alone or in combination with exercise in 36 young (36.8 +/- 1.0 y, overweight (body mass index, 27.8 +/- 0.7 kg/m(2 individuals randomized into one of three groups for a 6-mo intervention: Control, 100% of energy requirements; CR, 25% caloric restriction; and CREX, caloric restriction with exercise (CREX, 12.5% CR + 12.5% increased energy expenditure (EE. In the controls, 24-h EE was unchanged, but in CR and CREX it was significantly reduced from baseline even after adjustment for the loss of metabolic mass (CR, -135 +/- 42 kcal/d, p = 0.002 and CREX, -117 +/- 52 kcal/d, p = 0.008. Participants in the CR and CREX groups had increased expression of genes encoding proteins involved in mitochondrial function such as PPARGC1A, TFAM, eNOS, SIRT1, and PARL (all, p < 0.05. In parallel, mitochondrial DNA content increased by 35% +/- 5% in the CR group (p = 0.005 and 21% +/- 4% in the CREX group (p < 0.004, with no change in the control group (2% +/- 2%. However, the activity of key mitochondrial enzymes of the TCA (tricarboxylic acid cycle (citrate synthase, beta-oxidation (beta-hydroxyacyl-CoA dehydrogenase, and electron transport chain (cytochrome C oxidase II was unchanged. DNA damage was reduced from baseline in the CR (-0.56 +/- 0.11 arbitrary units, p = 0.003 and CREX (-0.45 +/- 0.12 arbitrary units, p = 0.011, but not in the controls. In primary cultures of human myotubes, a nitric oxide donor (mimicking eNOS signaling induced mitochondrial biogenesis but failed to induce SIRT1 protein expression, suggesting that additional factors may regulate SIRT1 content during CR.The observed increase in

  10. Effect of Aging on Mitochondrial Energetics in the Human Atria.

    Science.gov (United States)

    Emelyanova, Larisa; Preston, Claudia; Gupta, Anu; Viqar, Maria; Negmadjanov, Ulugbek; Edwards, Stacie; Kraft, Kelsey; Devana, Kameswari; Holmuhamedov, Ekhson; O'Hair, Daniel; Tajik, A Jamil; Jahangir, Arshad

    2017-08-19

    Energy production in myocardial cells occurs mainly in the mitochondrion. Although alterations in mitochondrial functions in the senescent heart have been documented, the molecular bases for the aging-associated decline in energy metabolism in the human heart are not fully understood. In this study, we examined transcription profiles of genes coding for mitochondrial proteins in atrial tissue from aged (≥65 years old) and comorbidities-matched adult (energetic pathways. These changes were associated with a significant decrease in respiratory capacity of mitochondria oxidizing glutamate and malate and functional activity of complex I activity that correlated with the downregulation of NDUFA6, NDUFA9, NDUFB5, NDUFB8, and NDUFS2 genes coding for NADH dehydrogenase subunits. Thus, aging is associated with a decline in activity of OXPHOS within the broader transcriptional downregulation of genes regulating mitochondrial energetics, providing a substrate for reduced energetic efficiency in the senescent human atria. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Mitochondrial DNA Polymerase POLG1 Disease Mutations and Germline Variants Promote Tumorigenic Properties.

    Science.gov (United States)

    Singh, Bhupendra; Owens, Kjerstin M; Bajpai, Prachi; Desouki, Mohamed Mokhtar; Srinivasasainagendra, Vinodh; Tiwari, Hemant K; Singh, Keshav K

    2015-01-01

    Germline mutations in mitochondrial DNA polymerase gamma (POLG1) induce mitochondrial DNA (mtDNA) mutations, depletion, and decrease oxidative phosphorylation. Earlier, we identified somatic mutations in POLG1 and the contribution of these mutations in human cancer. However, a role for germline variations in POLG1 in human cancers is unknown. In this study, we examined a role for disease associated germline variants of POLG1, POLG1 gene expression, copy number variation and regulation in human cancers. We analyzed the mutations, expression and copy number variation in POLG1 in several cancer databases and validated the analyses in primary breast tumors and breast cancer cell lines. We discovered 5-aza-2'-deoxycytidine led epigenetic regulation of POLG1, mtDNA-encoded genes and increased mitochondrial respiration. We conducted comprehensive race based bioinformatics analyses of POLG1 gene in more than 33,000 European-Americans and 5,000 African-Americans. We identified a mitochondrial disease causing missense variation in polymerase domain of POLG1 protein at amino acid 1143 (E1143G) to be 25 times more prevalent in European-Americans (allele frequency 0.03777) when compared to African-American (allele frequency 0.00151) population. We identified T251I and P587L missense variations in exonuclease and linker region of POLG1 also to be more prevalent in European-Americans. Expression of these variants increased glucose consumption, decreased ATP production and increased matrigel invasion. Interestingly, conditional expression of these variants revealed that matrigel invasion properties conferred by these germline variants were reversible suggesting a role of epigenetic regulators. Indeed, we identified a set of miRNA whose expression was reversible after variant expression was turned off. Together, our studies demonstrate altered genetic and epigenetic regulation of POLG1 in human cancers and suggest a role for POLG1 germline variants in promoting tumorigenic

  12. Statin-induced changes in mitochondrial respiration in blood platelets in rats and human with dyslipidemia.

    Science.gov (United States)

    Vevera, J; Fišar, Z; Nekovářová, T; Vrablík, M; Zlatohlávek, L; Hroudová, J; Singh, N; Raboch, J; Valeš, K

    2016-11-23

    3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) are widely used drugs for lowering blood lipid levels and preventing cardiovascular diseases. However, statins can have serious adverse effects, which may be related to development of mitochondrial dysfunctions. The aim of study was to demonstrate the in vivo effect of high and therapeutic doses of statins on mitochondrial respiration in blood platelets. Model approach was used in the study. Simvastatin was administered to rats at a high dose for 4 weeks. Humans were treated with therapeutic doses of rosuvastatin or atorvastatin for 6 weeks. Platelet mitochondrial respiration was measured using high-resolution respirometry. In rats, a significantly lower physiological respiratory rate was found in intact platelets of simvastatin-treated rats compared to controls. In humans, no significant changes in mitochondrial respiration were detected in intact platelets; however, decreased complex I-linked respiration was observed after statin treatment in permeabilized platelets. We propose that the small in vivo effect of statins on platelet energy metabolism can be attributed to drug effects on complex I of the electron transport system. Both intact and permeabilized platelets can be used as a readily available biological model to study changes in cellular energy metabolism in patients treated with statins.

  13. Introduction of disease-related mitochondrial DNA deletions into HeLa cells lacking mitochondrial DNA results in mitochondrial dysfunction.

    OpenAIRE

    Hayashi, J; Ohta, S.; Kikuchi, A; Takemitsu, M; Goto, Y.; Nonaka, I

    1991-01-01

    Mutant mitochondrial DNA with large-scale deletions (delta-mtDNA) has been frequently observed in patients with chronic progressive external ophthalmoplegia (CPEO), a subgroup of the mitochondrial encephalomyopathies. To exclude involvement of the nuclear genome in expression of the mitochondrial dysfunction characteristic of CPEO, we introduced the mtDNA of a CPEO patient into clonal mtDNA-less HeLa cells and isolated cybrid clones. Quantitation of delta-mtDNA in the cybrids revealed that de...

  14. Diverse Cytopathologies in Mitochondrial Disease Are Caused by AMP-activated Protein Kinase Signaling

    OpenAIRE

    Paul B. Bokko; Francione, Lisa; Bandala-Sanchez, Esther; Ahmed, Afsar U.; Sarah J. Annesley; Huang, Xiuli; Khurana, Taruna; Kimmel, Alan R.; Fisher, Paul R.

    2007-01-01

    The complex cytopathology of mitochondrial diseases is usually attributed to insufficient ATP. AMP-activated protein kinase (AMPK) is a highly sensitive cellular energy sensor that is stimulated by ATP-depleting stresses. By antisense-inhibiting chaperonin 60 expression, we produced mitochondrially diseased strains with gene dose-dependent defects in phototaxis, growth, and multicellular morphogenesis. Mitochondrial disease was phenocopied in a gene dose-dependent manner by overexpressing a c...

  15. Transcriptional regulation of the human mitochondrial peptide deformylase (PDF).

    Science.gov (United States)

    Pereira-Castro, Isabel; Costa, Luís Teixeira da; Amorim, António; Azevedo, Luisa

    2012-05-18

    The last years of research have been particularly dynamic in establishing the importance of peptide deformylase (PDF), a protein of the N-terminal methionine excision (NME) pathway that removes formyl-methionine from mitochondrial-encoded proteins. The genomic sequence of the human PDF gene is shared with the COG8 gene, which encodes a component of the oligomeric golgi complex, a very unusual case in Eukaryotic genomes. Since PDF is crucial in maintaining mitochondrial function and given the atypical short distance between the end of COG8 coding sequence and the PDF initiation codon, we investigated whether the regulation of the human PDF is affected by the COG8 overlapping partner. Our data reveals that PDF has several transcription start sites, the most important of which only 18 bp from the initiation codon. Furthermore, luciferase-activation assays using differently-sized fragments defined a 97 bp minimal promoter region for human PDF, which is capable of very strong transcriptional activity. This fragment contains a potential Sp1 binding site highly conserved in mammalian species. We show that this binding site, whose mutation significantly reduces transcription activation, is a target for the Sp1 transcription factor, and possibly of other members of the Sp family. Importantly, the entire minimal promoter region is located after the end of COG8's coding region, strongly suggesting that the human PDF preserves an independent regulation from its overlapping partner. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Major genomic mitochondrial lineages delineate early human expansions

    Directory of Open Access Journals (Sweden)

    Flores Carlos

    2001-08-01

    Full Text Available Abstract Background The phylogeographic distribution of human mitochondrial DNA variations allows a genetic approach to the study of modern Homo sapiens dispersals throughout the world from a female perspective. As a new contribution to this study we have phylogenetically analysed complete mitochondrial DNA(mtDNA sequences from 42 human lineages, representing major clades with known geographic assignation. Results We show the relative relationships among the 42 lineages and present more accurate temporal calibrations than have been previously possible to give new perspectives as how modern humans spread in the Old World. Conclusions The first detectable expansion occurred around 59,000–69,000 years ago from Africa, independently colonizing western Asia and India and, following this southern route, swiftly reaching east Asia. Within Africa, this expansion did not replace but mixed with older lineages detectable today only in Africa. Around 39,000–52,000 years ago, the western Asian branch spread radially, bringing Caucasians to North Africa and Europe, also reaching India, and expanding to north and east Asia. More recent migrations have entangled but not completely erased these primitive footprints of modern human expansions.

  17. 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......-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...

  18. NAD(+)-dependent activation of Sirt1 corrects the phenotype in a mouse model of mitochondrial disease.

    Science.gov (United States)

    Cerutti, Raffaele; Pirinen, Eija; Lamperti, Costanza; Marchet, Silvia; Sauve, Anthony A; Li, Wei; Leoni, Valerio; Schon, Eric A; Dantzer, Françoise; Auwerx, Johan; Viscomi, Carlo; Zeviani, Massimo

    2014-06-03

    Mitochondrial disorders are highly heterogeneous conditions characterized by defects of the mitochondrial respiratory chain. Pharmacological activation of mitochondrial biogenesis has been proposed as an effective means to correct the biochemical defects and ameliorate the clinical phenotype in these severely disabling, often fatal, disorders. Pathways related to mitochondrial biogenesis are targets of Sirtuin1, a NAD(+)-dependent protein deacetylase. As NAD(+) boosts the activity of Sirtuin1 and other sirtuins, intracellular levels of NAD(+) play a key role in the homeostatic control of mitochondrial function by the metabolic status of the cell. We show here that supplementation with nicotinamide riboside, a natural NAD(+) precursor, or reduction of NAD(+) consumption by inhibiting the poly(ADP-ribose) polymerases, leads to marked improvement of the respiratory chain defect and exercise intolerance of the Sco2 knockout/knockin mouse, a mitochondrial disease model characterized by impaired cytochrome c oxidase biogenesis. This strategy is potentially translatable into therapy of mitochondrial disorders in humans. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Mapping gene associations in human mitochondria using clinical disease phenotypes.

    Directory of Open Access Journals (Sweden)

    Curt Scharfe

    2009-04-01

    Full Text Available Nuclear genes encode most mitochondrial proteins, and their mutations cause diverse and debilitating clinical disorders. To date, 1,200 of these mitochondrial genes have been recorded, while no standardized catalog exists of the associated clinical phenotypes. Such a catalog would be useful to develop methods to analyze human phenotypic data, to determine genotype-phenotype relations among many genes and diseases, and to support the clinical diagnosis of mitochondrial disorders. Here we establish a clinical phenotype catalog of 174 mitochondrial disease genes and study associations of diseases and genes. Phenotypic features such as clinical signs and symptoms were manually annotated from full-text medical articles and classified based on the hierarchical MeSH ontology. This classification of phenotypic features of each gene allowed for the comparison of diseases between different genes. In turn, we were then able to measure the phenotypic associations of disease genes for which we calculated a quantitative value that is based on their shared phenotypic features. The results showed that genes sharing more similar phenotypes have a stronger tendency for functional interactions, proving the usefulness of phenotype similarity values in disease gene network analysis. We then constructed a functional network of mitochondrial genes and discovered a higher connectivity for non-disease than for disease genes, and a tendency of disease genes to interact with each other. Utilizing these differences, we propose 168 candidate genes that resemble the characteristic interaction patterns of mitochondrial disease genes. Through their network associations, the candidates are further prioritized for the study of specific disorders such as optic neuropathies and Parkinson disease. Most mitochondrial disease phenotypes involve several clinical categories including neurologic, metabolic, and gastrointestinal disorders, which might indicate the effects of gene defects

  20. Mitochondrial fragmentation in human macrophages attenuates palmitate-induced inflammatory responses.

    Science.gov (United States)

    Zezina, Ekaterina; Snodgrass, Ryan G; Schreiber, Yannick; Zukunft, Sven; Schürmann, Christoph; Heringdorf, Dagmar Meyer Zu; Geisslinger, Gerd; Fleming, Ingrid; Brandes, Ralf P; Brüne, Bernhard; Namgaladze, Dmitry

    2018-02-02

    Macrophages in adipose tissue contribute to inflammation and the development of insulin resistance in obesity. Exposure of macrophages to saturated fatty acids alters cell metabolism and activates pro-inflammatory signaling. How fatty acids influence macrophage mitochondrial dynamics is unclear. We investigated the mechanism of palmitate-induced mitochondrial fragmentation and its impact on inflammatory responses in primary human macrophages. Fatty acids, such as palmitate, caused mitochondrial fragmentation in human macrophages. Increased mitochondrial fragmentation was also observed in peritoneal macrophages from hyperlipidemic apolipoprotein E knockout mice. Fatty acid-induced mitochondrial fragmentation was independent of the fatty acid chain saturation and required dynamin-related protein 1 (DRP1). Mechanistically, mitochondrial fragmentation was regulated by incorporation of palmitate into mitochondrial phospholipids and their precursors. Palmitate-induced endoplasmic reticulum stress and loss of mitochondrial membrane potential did not contribute to mitochondrial fragmentation. Macrophages treated with palmitate maintained intact mitochondrial respiration and ATP levels. Pharmacological or genetic inhibition of DRP1 enhanced palmitate-induced mitochondrial ROS production, c-Jun phosphorylation, and inflammatory cytokine expression. Our results indicate that mitochondrial fragmentation is a protective mechanism attenuating inflammatory responses induced by palmitate in human macrophages. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Mitochondrial fusion, fission, and mitochondrial toxicity.

    Science.gov (United States)

    Meyer, Joel N; Leuthner, Tess C; Luz, Anthony L

    2017-08-05

    Mitochondrial dynamics are regulated by two sets of opposed processes: mitochondrial fusion and fission, and mitochondrial biogenesis and degradation (including mitophagy), as well as processes such as intracellular transport. These processes maintain mitochondrial homeostasis, regulate mitochondrial form, volume and function, and are increasingly understood to be critical components of the cellular stress response. Mitochondrial dynamics vary based on developmental stage and age, cell type, environmental factors, and genetic background. Indeed, many mitochondrial homeostasis genes are human disease genes. Emerging evidence indicates that deficiencies in these genes often sensitize to environmental exposures, yet can also be protective under certain circumstances. Inhibition of mitochondrial dynamics also affects elimination of irreparable mitochondrial DNA (mtDNA) damage and transmission of mtDNA mutations. We briefly review the basic biology of mitodynamic processes with a focus on mitochondrial fusion and fission, discuss what is known and unknown regarding how these processes respond to chemical and other stressors, and review the literature on interactions between mitochondrial toxicity and genetic variation in mitochondrial fusion and fission genes. Finally, we suggest areas for future research, including elucidating the full range of mitodynamic responses from low to high-level exposures, and from acute to chronic exposures; detailed examination of the physiological consequences of mitodynamic alterations in different cell types; mechanism-based testing of mitotoxicant interactions with interindividual variability in mitodynamics processes; and incorporating other environmental variables that affect mitochondria, such as diet and exercise. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Mitochondrial defects and oxidative stress in Alzheimer disease and Parkinson disease.

    Science.gov (United States)

    Yan, Michael H; Wang, Xinglong; Zhu, Xiongwei

    2013-09-01

    Alzheimer disease (AD) and Parkinson disease (PD) are the two most common age-related neurodegenerative diseases characterized by prominent neurodegeneration in selective neural systems. Although a small fraction of AD and PD cases exhibit evidence of heritability, among which many genes have been identified, the majority are sporadic without known causes. Molecular mechanisms underlying neurodegeneration and pathogenesis of these diseases remain elusive. Convincing evidence demonstrates oxidative stress as a prominent feature in AD and PD and links oxidative stress to the development of neuronal death and neural dysfunction, which suggests a key pathogenic role for oxidative stress in both AD and PD. Notably, mitochondrial dysfunction is also a prominent feature in these diseases, which is likely to be of critical importance in the genesis and amplification of reactive oxygen species and the pathophysiology of these diseases. In this review, we focus on changes in mitochondrial DNA and mitochondrial dynamics, two aspects critical to the maintenance of mitochondrial homeostasis and function, in relationship with oxidative stress in the pathogenesis of AD and PD. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Study of mitochondrial respiratory defects on reprogramming to human induced pluripotent stem cells

    Science.gov (United States)

    Hung, Sandy S.C.; Van Bergen, Nicole J.; Jackson, Stacey; Liang, Helena; Mackey, David A.; Hernández, Damián; Lim, Shiang Y.; Hewitt, Alex W.; Trounce, Ian; Pébay, Alice; Wong, Raymond C.B.

    2016-01-01

    Reprogramming of somatic cells into a pluripotent state is known to be accompanied by extensive restructuring of mitochondria and switch in metabolic requirements. Here we utilized Leber's hereditary optic neuropathy (LHON) as a mitochondrial disease model to study the effects of homoplasmic mtDNA mutations and subsequent oxidative phosphorylation (OXPHOS) defects in reprogramming. We obtained fibroblasts from a total of 6 LHON patients and control subjects, and showed a significant defect in complex I respiration in LHON fibroblasts by high-resolution respiratory analysis. Using episomal vector reprogramming, our results indicated that human induced pluripotent stem cell (hiPSC) generation is feasible in LHON fibroblasts. In particular, LHON-specific OXPHOS defects in fibroblasts only caused a mild reduction and did not significantly affect reprogramming efficiency, suggesting that hiPSC reprogramming can tolerate a certain degree of OXPHOS defects. Our results highlighted the induction of genes involved in mitochondrial biogenesis (TFAM, NRF1), mitochondrial fusion (MFN1, MFN2) and glycine production (GCAT) during reprogramming. However, LHON-associated OXPHOS defects did not alter the kinetics or expression levels of these genes during reprogramming. Together, our study provides new insights into the effects of mtDNA mutation and OXPHOS defects in reprogramming and genes associated with various aspects of mitochondrial biology. PMID:27127184

  4. Human Environmental Disease Network

    DEFF Research Database (Denmark)

    Taboureau, Olivier; Audouze, Karine

    2017-01-01

    During the past decades, many epidemiological, toxicological and biological studies have been performed to assess the role of environmental chemicals as potential toxicants for diverse human disorders. However, the relationships between diseases based on chemical exposure have been rarely studied...... by computational biology. We developed a human environmental disease network (EDN) to explore and suggest novel disease-disease and chemical-disease relationships. The presented scored EDN model is built upon the integration on systems biology and chemical toxicology using chemical contaminants information...

  5. S-glutathionylation reactions in mitochondrial function and disease

    Directory of Open Access Journals (Sweden)

    Ryan J. Mailloux

    2014-11-01

    Full Text Available Mitochondria are highly efficient energy-transforming organelles that convert energy stored in carbon bonds into the universal energy currency ATP. The production of ATP by mitochondria is dependent on oxidation of nutrients and coupling of exergonic electron transfer reactions to the genesis of transmembrane electrochemical potential of protons. Electrons can also prematurely spin-off from the respiratory complexes and univalently reduce di-oxygen to generate ROS, an important signaling molecule that can be toxic at high concentrations. Production of ATP and ROS are intimately linked by the respiratory chain and the genesis of one or the other inherently depends on the metabolic state of mitochondria. Various control mechanisms converge on mitochondria to adjust ATP and ROS output in response to changing cellular demands. One control mechanism that has gained a high amount of attention recently is S-glutathionylation, a redox sensitive covalent modification that involves formation of a disulfide bridge between glutathione and an available protein cysteine thiol. A number of S-glutathionylation targets have been identified in mitochondria. It has also been established that S-glutathionylation reactions in mitochondria are mediated by the thiol oxidoreductase glutaredoxin-2 (Grx2. In the following review, emerging knowledge on S-glutathionylation reactions and its importance in modulation mitochondrial ATP and ROS production will be discussed. Major focus will be placed on Complex I of the respiratory chain since 1 it is a target for reversible S-glutathionylation by Grx2 and 2 deregulation of Complex I S-glutathionylation is associated with development of various disease states particularly heart disease. Other mitochondrial enzymes and how their S-glutathionylation profile is affected in different disease states will also be discussed.

  6. Prevalence and Severity of Voice and Swallowing Difficulties in Mitochondrial Disease

    Science.gov (United States)

    Read, Jennifer L.; Whittaker, Roger G.; Miller, Nick; Clark, Sue; Taylor, Robert; McFarland, Robert; Turnbull, Douglass

    2012-01-01

    Background: Mutations of mitochondrial DNA (mtDNA) cause a broad spectrum of clinical phenotypes. Anecdotal evidence suggests that voice and swallow problems are a common feature of these diseases. Aims: To characterize accurately the prevalence and severity of voice and swallow problems in a large cohort of patients with mitochondrial disease.…

  7. The role of mitochondrial dysfunction in the progression of Alzheimer’s disease

    DEFF Research Database (Denmark)

    Desler, Claus; Lillenes, Meryl S.; Tønjum, Tone

    2018-01-01

    The current molecular understanding of Alzheimer’s disease (AD) has still not resulted in successful interventions. Mitochondrial dysfunction of the AD brain is currently emerging as a hallmark of this disease. One mitochondrial function often affected in AD is oxidative phosphorylation responsible...

  8. Mitochondrial haplogroups

    DEFF Research Database (Denmark)

    Benn, Marianne; Schwartz, Marianne; Nordestgaard, Børge G

    2008-01-01

    Rare mutations in the mitochondrial genome may cause disease. Mitochondrial haplogroups defined by common polymorphisms have been associated with risk of disease and longevity. We tested the hypothesis that common haplogroups predict risk of ischemic cardiovascular disease, morbidity from other...

  9. Amyloid-beta leads to impaired cellular respiration, energy production and mitochondrial electron chain complex activities in human neuroblastoma cells.

    Science.gov (United States)

    Rhein, V; Baysang, G; Rao, S; Meier, F; Bonert, A; Müller-Spahn, F; Eckert, A

    2009-09-01

    Evidence suggests that amyloid-beta (Abeta) protein is a key factor in the pathogenesis of Alzheimer's disease (AD) and it has been recently proposed that mitochondria are involved in the biochemical pathway by which Abeta can lead to neuronal dysfunction. Here we investigated the specific effects of Abeta on mitochondrial function under physiological conditions. Mitochondrial respiratory functions and energy metabolism were analyzed in control and in human wild-type amyloid precursor protein (APP) stably transfected human neuroblastoma cells (SH-SY5Y). Mitochondrial respiratory capacity of mitochondrial electron transport chain (ETC) in vital cells was measured with a high-resolution respirometry system (Oxygraph-2k). In addition, we determined the individual activities of mitochondrial complexes I-IV that compose ETC and ATP cellular levels. While the activities of complexes I and II did not change between cell types, complex IV activity was significantly reduced in APP cells. In contrast, activity of complex III was significantly enhanced in APP cells, as compensatory response in order to balance the defect of complex IV. However, this compensatory mechanism could not prevent the strong impairment of total respiration in vital APP cells. As a result, the respiratory control ratio (state3/state4) together with ATP production decreased in the APP cells in comparison with the control cells. Chronic exposure to soluble Abeta protein may result in an impairment of energy homeostasis due to a decreased respiratory capacity of mitochondrial electron transport chain which, in turn, may accelerate neurons demise.

  10. Analysis of human mitochondrial DNA sequences from fecally polluted environmental waters as a tool to study population diversity

    Directory of Open Access Journals (Sweden)

    Vikram Kapoor

    2017-05-01

    Full Text Available Mitochondrial signature sequences have frequently been used to study human population diversity around the world. Traditionally, this requires obtaining samples directly from individuals which is cumbersome, time consuming and limited to the number of individuals that participated in these types of surveys. Here, we used environmental DNA extracts to determine the presence and sequence variability of human mitochondrial sequences as a means to study the diversity of populations inhabiting in areas nearby a tropical watershed impacted with human fecal pollution. We used high-throughput sequencing (Illumina and barcoding to obtain thousands of sequences from the mitochondrial hypervariable region 2 (HVR2 and determined the different haplotypes present in 10 different water samples. Sequence analyses indicated a total of 19 distinct variants with frequency greater than 5%. The HVR2 sequences were associated with haplogroups of West Eurasian (57.6%, Sub-Saharan African (23.9%, and American Indian (11% ancestry. This was in relative accordance with population census data from the watershed sites. The results from this study demonstrates the potential value of mitochondrial sequence data retrieved from fecally impacted environmental waters to study the population diversity of local municipalities. This environmental DNA approach may also have other public health implications such as tracking background levels of human mitochondrial genes associated with diseases. It may be possible to expand this approach to other animal species inhabiting or using natural water systems.

  11. Movement disorders in genetically confirmed mitochondrial disease and the putative role of the cerebellum.

    Science.gov (United States)

    Schreglmann, Sebastian R; Riederer, Franz; Galovic, Marian; Ganos, Christos; Kägi, Georg; Waldvogel, Daniel; Jaunmuktane, Zane; Schaller, Andre; Hidding, Ute; Krasemann, Ernst; Michels, Lars; Baumann, Christian R; Bhatia, Kailash; Jung, Hans H

    2018-01-01

    Mitochondrial disease can present as a movement disorder. Data on this entity's epidemiology, genetics, and underlying pathophysiology, however, is scarce. The objective of this study was to describe the clinical, genetic, and volumetric imaging data from patients with mitochondrial disease who presented with movement disorders. In this retrospective analysis of all genetically confirmed mitochondrial disease cases from three centers (n = 50), the prevalence and clinical presentation of video-documented movement disorders was assessed. Voxel-based morphometry from high-resolution MRI was employed to compare cerebral and cerebellar gray matter volume between mitochondrial disease patients with and without movement disorders and healthy controls. Of the 50 (30%) patients with genetically confirmed mitochondrial disease, 15 presented with hypokinesia (parkinsonism 3/15), hyperkinesia (dystonia 5/15, myoclonus 3/15, chorea 2/15), and ataxia (3/15). In 3 patients, mitochondrial disease presented as adult-onset isolated dystonia. In comparison to healthy controls and mitochondrial disease patients without movement disorders, patients with hypo- and hyperkinetic movement disorders had significantly more cerebellar atrophy and an atrophy pattern predominantly involving cerebellar lobules VI and VII. This series provides clinical, genetic, volumetric imaging, and histologic data that indicate major involvement of the cerebellum in mitochondrial disease when it presents with hyper- and hypokinetic movement disorders. As a working hypothesis addressing the particular vulnerability of the cerebellum to energy deficiency, this adds substantially to the pathophysiological understanding of movement disorders in mitochondrial disease. Furthermore, it provides evidence that mitochondrial disease can present as adult-onset isolated dystonia. © 2017 International Parkinson and Movement Disorder Society. © 2017 International Parkinson and Movement Disorder Society.

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

    NARCIS (Netherlands)

    Rooijers, K.; Loayza-Puch, F.; Nijtmans, L.G.J.; Agami, R.

    2013-01-01

    Mitochondria 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 mutations

  13. 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

  14. RNA silencing of genes involved in Alzheimer's disease enhances mitochondrial function and synaptic activity.

    Science.gov (United States)

    Manczak, Maria; Reddy, P Hemachandra

    2013-12-01

    An age-dependent increase in mRNA levels of the amyloid precursor protein (APP), the microtubule-associated protein Tau, and voltage-dependent anion channel 1 (VDAC1) genes are reported to be toxic to neurons affected by Alzheimer's disease (AD). However, the underlying toxic nature of these genes is not completely understood. The purpose of our study was to determine the effects of RNA silencing of APP, Tau, and VDAC1 genes in AD pathogenesis. Using human neuroblastoma (SHSY5Y) cells, we first silenced RNA for APP, Tau, and VDAC1 genes, and then performed real-time RT-PCR analysis to measure mRNA levels of 34 genes that are involved in AD pathogenesis. Using biochemical assays, we also assessed mitochondrial function by measuring levels of H2O2 production, lipid peroxidation, cytochrome c oxidase activity, ATP production, and GTPase enzymatic activity. We found that increased mRNA expression of synaptic function and mitochondrial fission genes, and reduced levels of mitochondrial fusion genes in RNA silenced the SHSY5Y cells for APP, Tau and VDAC1 genes relative to the control SHSY5Y cells. In addition, RNA-silenced APP, Tau, and VDAC1 genes in SHSY5Y cells showed reduced levels of H2O2 production, lipid peroxidation, fission-linked GTPase activity, and increased cytochrome oxidase activity and ATP production. These findings suggest that a reduction of human APP, Tau, and VDAC1 may enhance synaptic activity, may improve mitochondrial maintenance and function, and may protect against toxicities of AD-related genes. Thus, these findings also suggest that the reduction of APP, Tau, and VDAC1 mRNA expressions may have therapeutic value for patients with AD. © 2013.

  15. Anti-mitochondrial antibodies in patients with Graves' disease may not signify primary biliary cirrhosis.

    OpenAIRE

    Perros, P.; Palmer, J. M.; Yeaman, S. J.; Kendall-Taylor, P.

    1994-01-01

    Two patients with Graves' disease were incidentally found to have anti-mitochondrial antibodies by immunofluorescence in the absence of symptoms, clinical signs or biochemical evidence of liver dysfunction. Anti-mitochondrial antibody titres became undetectable in both patients on follow-up. Screening of the patients' sera by immunoblotting against the purified antigens of the M2 complex was negative. We conclude that in these cases, anti-mitochondrial antibodies detected by immunofluorescenc...

  16. Mitochondrial Reactive Oxygen Species Mediate Cardiac Structural, Functional, and Mitochondrial Consequences of Diet-Induced Metabolic Heart Disease.

    Science.gov (United States)

    Sverdlov, Aaron L; Elezaby, Aly; Qin, Fuzhong; Behring, Jessica B; Luptak, Ivan; Calamaras, Timothy D; Siwik, Deborah A; Miller, Edward J; Liesa, Marc; Shirihai, Orian S; Pimentel, David R; Cohen, Richard A; Bachschmid, Markus M; Colucci, Wilson S

    2016-01-11

    Mitochondrial reactive oxygen species (ROS) are associated with metabolic heart disease (MHD). However, the mechanism by which ROS cause MHD is unknown. We tested the hypothesis that mitochondrial ROS are a key mediator of MHD. Mice fed a high-fat high-sucrose (HFHS) diet develop MHD with cardiac diastolic and mitochondrial dysfunction that is associated with oxidative posttranslational modifications of cardiac mitochondrial proteins. Transgenic mice that express catalase in mitochondria and wild-type mice were fed an HFHS or control diet for 4 months. Cardiac mitochondria from HFHS-fed wild-type mice had a 3-fold greater rate of H2O2 production (P=0.001 versus control diet fed), a 30% decrease in complex II substrate-driven oxygen consumption (P=0.006), 21% to 23% decreases in complex I and II substrate-driven ATP synthesis (P=0.01), and a 62% decrease in complex II activity (P=0.002). In transgenic mice that express catalase in mitochondria, all HFHS diet-induced mitochondrial abnormalities were ameliorated, as were left ventricular hypertrophy and diastolic dysfunction. In HFHS-fed wild-type mice complex II substrate-driven ATP synthesis and activity were restored ex vivo by dithiothreitol (5 mmol/L), suggesting a role for reversible cysteine oxidative posttranslational modifications. In vitro site-directed mutation of complex II subunit B Cys100 or Cys103 to redox-insensitive serines prevented complex II dysfunction induced by ROS or high glucose/high palmitate in the medium. Mitochondrial ROS are pathogenic in MHD and contribute to mitochondrial dysfunction, at least in part, by causing oxidative posttranslational modifications of complex I and II proteins including reversible oxidative posttranslational modifications of complex II subunit B Cys100 and Cys103. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  17. Resistance Exercise Training Alters Mitochondrial Function in Human Skeletal Muscle.

    Science.gov (United States)

    Porter, Craig; Reidy, Paul T; Bhattarai, Nisha; Sidossis, Labros S; Rasmussen, Blake B

    2015-09-01

    Loss of mitochondrial competency is associated with several chronic illnesses. Therefore, strategies that maintain or increase mitochondrial function will likely be of benefit in numerous clinical settings. Endurance exercise has long been known to increase mitochondrial function in the skeletal muscle. Comparatively little is known regarding the effect of resistance exercise training (RET) on skeletal muscle mitochondrial respiratory function. The purpose of the current study was to determine the effect of chronic resistance training on skeletal muscle mitochondrial respiratory capacity and function. Here, we studied the effect of a 12-wk RET program on skeletal muscle mitochondrial function in 11 young healthy men. Muscle biopsies were collected before and after the 12-wk training program, and mitochondrial respiratory capacity was determined in permeabilized myofibers by high-resolution respirometry. RET increased lean body mass and quadriceps muscle strength by 4% and 15%, respectively (P training (P function of skeletal muscle mitochondria.

  18. Human and mouse mitochondrial orthologs of bacterial ClpX

    DEFF Research Database (Denmark)

    Corydon, T J; Wilsbech, M; Jespersgaard, C

    2000-01-01

    We have determined the cDNA sequence and exon/intron structure of the human CLPX gene encoding a human ortholog of the E. coli ClpX chaperone and protease subunit. The CLPX gene comprises 14 exons and encodes a 633-amino acid-long precursor polypeptide. The polypeptide contains an N...... variability between mouse ClpX cDNAs from different strains. Alignment of the human and mouse ClpX amino acid sequences with ClpX sequences from other organisms shows that they display the typical modular organization of domains with one AAA(+) domain common to a large group of ATPases and several other......-terminal putative mitochondrial transit peptide, and expression of a full-length ClpX cDNA tagged at its C-terminus (Myc-His) shows that the polypeptide is transported into mitochondria. FISH analysis localized the CLPX gene to human Chromosome (Chr) 15q22.1-22.32. This localization was refined by radiation hybrid...

  19. The role of mitochondrial DNA mutation on neurodegenerative diseases

    OpenAIRE

    Cha, Moon-Yong; Kim, Dong Kyu; Mook-Jung, Inhee

    2015-01-01

    Many researchers have reported that oxidative damage to mitochondrial DNA (mtDNA) is increased in several age-related disorders. Damage to mitochondrial constituents and mtDNA can generate additional mitochondrial dysfunction that may result in greater reactive oxygen species production, triggering a circular chain of events. However, the mechanisms underlying this vicious cycle have yet to be fully investigated. In this review, we summarize the relationship of oxidative stress-induced mitoch...

  20. [Autism, epilepsy and mitochondrial disease: points of contact].

    Science.gov (United States)

    García-Peñas, J J

    2008-01-01

    Autism is a neurodevelopmental disorder with unknown etiology, although several different specific organic conditions have been found to be associated with autism in about 10 to 37% of cases. Autism with regression has been reported in one third of autistic children with previously normal development. Epilepsy is quite common in autism spectrum disorders. The rate of comorbidity varies between 20-30% of cases, depending upon the age and type of disorder. Major risk factors for epilepsy in autistic children are mental retardation and additional neurological disorders, as well as some specific associated medical conditions like chromosomal abnormalities, phakomatosis and inherited metabolic disorders. To review the possible linkage between autism, epilepsy and mitochondrial dysfunction. The hypothesis of a disturbed bioenergetic metabolism underlying autism has been suggested by the detection of high lactate levels in some patients. Although the mechanism of hyperlactacidemia remains unknown, a likely possibility involves mitochondrial oxidative phosphorylation dysfunction in neuronal cells. Reduced levels of respiratory mitochondrial enzymes, ultraestructural mitochondrial abnormalities and a broad range of mitochondrial DNA mutations suggest a linkage between autism, epilepsy and mitochondrial disorders. Though mitochondrial disorders are a rare cause of autism in children, we must keep in mind this etiology in autistic patients with epilepsy and associated signs of neurologic and/or systemic dysfunction. Finding biochemical or structural mitochondrial abnormalities in an autistic child does not necessarily imply a primary mitochondrial disorder but can also be secondary to technical inaccuracies or another genetic disorder.

  1. The role of mitochondrial DNA mutation on neurodegenerative diseases.

    Science.gov (United States)

    Cha, Moon-Yong; Kim, Dong Kyu; Mook-Jung, Inhee

    2015-03-13

    Many researchers have reported that oxidative damage to mitochondrial DNA (mtDNA) is increased in several age-related disorders. Damage to mitochondrial constituents and mtDNA can generate additional mitochondrial dysfunction that may result in greater reactive oxygen species production, triggering a circular chain of events. However, the mechanisms underlying this vicious cycle have yet to be fully investigated. In this review, we summarize the relationship of oxidative stress-induced mitochondrial dysfunction with mtDNA mutation in neurodegenerative disorders.

  2. Mitochondrial Oxidative Damage in Aging and Alzheimer's Disease: Implications for Mitochondrially Targeted Antioxidant Therapeutics

    OpenAIRE

    P. Hemachandra Reddy

    2006-01-01

    The overall aim of this article is to review current therapeutic strategies for treating AD, with a focus on mitochondrially targeted antioxidant treatments. Recent advances in molecular, cellular, and animal model studies of AD have revealed that amyloid precursor protein derivatives, including amyloid beta (Aβ) monomers and oligomers, are likely key factors in tau hyperphosphorylation, mitochondrial oxidative damage, inflammatory changes, and synaptic failure in the brain ...

  3. Cerebrospinal fluid mitochondrial DNA in the Alzheimer's disease continuum.

    Science.gov (United States)

    Cervera-Carles, Laura; Alcolea, Daniel; Estanga, Ainara; Ecay-Torres, Mirian; Izagirre, Andrea; Clerigué, Montserrat; García-Sebastián, Maite; Villanúa, Jorge; Escalas, Clàudia; Blesa, Rafael; Martínez-Lage, Pablo; Lleó, Alberto; Fortea, Juan; Clarimón, Jordi

    2017-05-01

    Low levels of cell-free mitochondrial DNA (mtDNA) in the cerebrospinal fluid (CSF) of Alzheimer's disease (AD) patients have been identified and proposed as a novel biomarker for the disease. The lack of validation studies of previous results prompted us to replicate this finding in a comprehensive series of patients and controls. We applied droplet digital polymerase chain reaction in CSF specimens from 124 patients representing the AD spectrum and 140 neurologically healthy controls. The following preanalytical and analytical parameters were evaluated: the effect of freeze-thaw cycles on mtDNA, the linearity of mtDNA load across serial dilutions, and the mtDNA levels in the diagnostic groups. We found a wide range of mtDNA copies, which resulted in a high degree of overlap between groups. Although the AD group presented significantly higher mtDNA counts, the receiver-operating characteristic analysis disclosed an area under the curve of 0.715 to distinguish AD patients from controls. MtDNA was highly stable with low analytical variability. In conclusion, mtDNA levels in CSF show a high interindividual variability, with great overlap within phenotypes and presents low sensitivity for AD. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Human prion diseases.

    Science.gov (United States)

    Thakur, Rajeev; Vincent, Yasmeen Marbaniang; Chaturvedi, Sujata

    2002-01-01

    Prion diseases is another name for a group of 'transmissible spongiform encephalopathies'. Creutzfeldt-Jakob disease, the first prion disease described in humans, occurs in sporadic, familial or iatrogenic form. Other transmissible spongiform encephalopathies in humans such as familial Creutzfeldt-]akob disease, Gerstmann-Sträussler-Scheinker disease and fatal familial Insomnia have been shown to be associated with specific prion protein gene mutations. In 1996, a new variant of Creutzfeldt-Jakob disease was reported in the United Kingdom among young patients with unusual clinical features and unique neuropathological findings. This new form could be due to transmission to humans of the agent causing bovine spongiform encephalopathy. While examination of brain tissue is the key to making a diagnosis, it is not always possible antemortem. Immunological tests such as ELISA or western blot assays along with tests for 1 4-3-3 protein in the cerebrospinal fluid remain the main tools of diagnosis. Conventional disinfection and sterilization practices are Ineffective for these agents. The unusual properties of prions pose a challenge for treatment, surveillance and control of these diseases.

  5. Amino acids variations in amyloid-beta peptides, mitochondrial dysfunction, and new therapies for Alzheimer's disease.

    Science.gov (United States)

    Atamna, Hani

    2009-10-01

    Soluble oligomers and/or aggregates of Amyloid-beta (Abeta) are viewed by many as the principal cause for neurodegeneration in Alzheimer's disease (AD). However, the mechanism by which Abeta and its aggregates cause neurodegeneration is not clear. The toxicity of Abeta has been attributed to its hydrophobicity. However, many specific mitochondrial cytopathologies e.g., loss of complex IV, loss of iron homeostasis, or oxidative damage cannot be explained by Abeta's hydrophobicity. In order to understand the role of Abeta in these cytopathologies we hypothesized that Abeta impairs specific metabolic pathways. We focused on heme metabolism because it links iron, mitochondria, and Abeta. We generated experimental evidence showing that Abeta alters heme metabolism in neuronal cells. Furthermore, we demonstrated that Abeta binds to and depletes intracellular regulatory heme (forming an Abeta-heme complex), which provides a strong molecular connection between Abeta and heme metabolism. We showed that heme depletion leads to key cytopathologies identical to those seen in AD including loss of iron homeostasis and loss of mitochondrial complex IV. Abeta-heme exhibits a peroxidase-like catalytic activity, which catalytically accelerates oxidative damage. Interestingly, the amino acids sequence of rodent Abeta (roAbeta) and human Abeta (huAbeta) is identical except for three amino acids within the hydrophilic region, which is also the heme-binding motif that we identified. We found that huAbeta, unlike roAbeta, binds heme tightly and forms a peroxidase. Although, roAbeta and huAbeta equally form fibrils and aggregates, rodents do not develop AD-like neuropathology. These findings led us to propose a new mechanism for mitochondrial dysfunction and huAbeta's neurotoxicity. This mechanism prompted the development of methylene blue (MB), which increased heme synthesis, complex IV, and mitochondrial function. Thus, MB may delay the onset and progression of AD and serve as a lead to

  6. Degree of glutathione deficiency and redox imbalance depend on subtype of mitochondrial disease and clinical status.

    Directory of Open Access Journals (Sweden)

    Gregory M Enns

    Full Text Available Mitochondrial disorders are associated with decreased energy production and redox imbalance. Glutathione plays a central role in redox signaling and protecting cells from oxidative damage. In order to understand the consequences of mitochondrial dysfunction on in vivo redox status, and to determine how this varies by mitochondrial disease subtype and clinical severity, we used a sensitive tandem mass spectrometry assay to precisely quantify whole blood reduced (GSH and oxidized (GSSG glutathione levels in a large cohort of mitochondrial disorder patients. Glutathione redox potential was calculated using the Nernst equation. Compared to healthy controls (n = 59, mitochondrial disease patients (n = 58 as a group showed significant redox imbalance (redox potential -251 mV ± 9.7, p<0.0001 with an increased level of oxidation by ∼ 9 mV compared to controls (-260 mV ± 6.4. Underlying this abnormality were significantly lower whole blood GSH levels (p = 0.0008 and GSH/GSSG ratio (p = 0.0002, and significantly higher GSSG levels (p<0.0001 in mitochondrial disease patients compared to controls. Redox potential was significantly more oxidized in all mitochondrial disease subgroups including Leigh syndrome (n = 15, electron transport chain abnormalities (n = 10, mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (n = 8, mtDNA deletion syndrome (n = 7, mtDNA depletion syndrome (n = 7, and miscellaneous other mitochondrial disorders (n = 11. Patients hospitalized in metabolic crisis (n = 7 showed the greatest degree of redox imbalance at -242 mV ± 7. Peripheral whole blood GSH and GSSG levels are promising biomarkers of mitochondrial dysfunction, and may give insights into the contribution of oxidative stress to the pathophysiology of the various mitochondrial disorders. In particular, evaluation of redox potential may be useful in monitoring of clinical status or response to redox-modulating therapies in clinical trials.

  7. Mitochondrial Dysfunction Triggers Synaptic Deficits via Activation of p38 MAP Kinase Signaling in Differentiated Alzheimer's Disease Trans-Mitochondrial Cybrid Cells.

    Science.gov (United States)

    Yu, Qing; Du, Fang; Douglas, Justin T; Yu, Haiyang; Yan, Shirley ShiDu; Yan, Shi Fang

    2017-01-01

    Loss of synapse and synaptic dysfunction contribute importantly to cognitive impairment in Alzheimer's disease (AD). Mitochondrial dysfunction and oxidative stress are early pathological features in AD-affected brain. However, the effect of AD mitochondria on synaptogenesis remains to be determined. Using human trans-mitochondrial "cybrid" (cytoplasmic hybrid) neuronal cells whose mitochondria were transferred from platelets of patients with sporadic AD or age-matched non-AD subjects with relatively normal cognition, we provide the first evidence of mitochondrial dysfunction compromises synaptic development and formation of synapse in AD cybrid cells in response to chemical-induced neuronal differentiation. Compared to non-AD control cybrids, AD cybrid cells showed synaptic loss which was evidenced by a significant reduction in expression of two synaptic marker proteins: synaptophysin (presynaptic marker) and postsynaptic density protein-95, and neuronal proteins (MAP-2 and NeuN) upon neuronal differentiation. In parallel, AD-mediated synaptic deficits correlate to mitochondrial dysfunction and oxidative stress as well as activation of p38 MAP kinase. Notably, inhibition of p38 MAP kinase by pharmacological specific p38 inhibitor significantly increased synaptic density, improved mitochondrial function, and reduced oxidative stress. These results suggest that activation of p38 MAP kinase signaling pathway contributes to AD-mediated impairment in neurogenesis, possibly by inhibiting the neuronal differentiation. Our results provide new insight into the crosstalk of dysfunctional AD mitochondria to synaptic formation and maturation via activation of p38 MAP kinase. Therefore, blockade of p38 MAP kinase signal transduction could be a potential therapeutic strategy for AD by alleviating loss of synapses.

  8. Mutation of C20orf7 Disrupts Complex I Assembly and Causes Lethal Neonatal Mitochondrial Disease

    NARCIS (Netherlands)

    Sugiana, Canny; Pagliarini, David J.; McKenzie, Matthew; Kirby, Denise M.; Salemi, Renato; Abu-Amero, Khaled K.; Dahl, Hans-Henrik M.; Hutchison, Wendy M.; Vascotto, Katherine A.; Smith, Stacey M.; Newbold, Robert F.; Christodoulou, John; Calvo, Sarah; Mootha, Vamsi K.; Ryan, Michael T.; Thorburn, David R.

    2008-01-01

    Complex I (NADH:ubiquinone oxidoreductase) is the first and largest multimeric complex of the mitochondrial respiratory chain. Human complex I comprises seven Subunits encoded by mitochondrial DNA and 38 nuclear-encoded subunits that are assembled together in a process that is only partially

  9. Peroxynitrite-mediated nitrosative stress decreases motility and mitochondrial membrane potential in human spermatozoa.

    Science.gov (United States)

    Uribe, P; Boguen, R; Treulen, F; Sánchez, R; Villegas, J V

    2015-03-01

    Nitrosative stress is produced by high levels of reactive nitrogen species (RNS). The RNS include peroxynitrite, a highly reactive free radical produced from a diffusion-controlled reaction between nitric oxide and superoxide anion. Peroxynitrite causes nitration and oxidation of lipids, proteins and DNA, and is thus considered an important pathogenic mechanism in various diseases. Although high levels of peroxynitrite are associated with astenozoospermia, few reports exist regarding the in vitro effect of high levels of this RNS on human sperm. The aim of this study was to evaluate the in vitro effect of nitrosative stress caused by peroxynitrite on the viability, motility and mitochondrial membrane potential of human spermatozoa. To do this, human spermatozoa from healthy donors were exposed in vitro to 3-morpholinosydnonimine (SIN-1), a molecule that generates peroxynitrite. Incubations were done at 37°C for up to 4 h with SIN-1 concentrations between 0.2 and 1.0 mmol/l. Generation of peroxynitrite was confirmed using dihydrorhodamine 123 (DHR) by spectrophotometry and flow cytometry. Sperm viability was assessed by propidium iodide staining; sperm motility was analyzed by CASA, and the state of mitochondrial membrane potential (ΔΨm) by JC-1 staining. Viability and ΔΨm were measured by flow cytometry. The results showed an increase in DHR oxidation, demonstrating the generation of peroxynitrite through SIN-1. Peroxynitrite decreased progressive and total motility, as well as some sperm kinetic parameters. Mitochondrial membrane potential also decreased. These alterations occurred with no decrease in sperm viability. In conclusion, peroxynitrite-induced nitrosative stress impairs vital functions in the male gamete, possibly contributing to male infertility. © The Author 2014. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Increased neuronal PreP activity reduces Aβ accumulation, attenuates neuroinflammation and improves mitochondrial and synaptic function in Alzheimer disease's mouse model

    Science.gov (United States)

    Fang, Du; Wang, Yongfu; Zhang, Zhihua; Du, Heng; Yan, Shiqiang; Sun, Qinru; Zhong, Changjia; Wu, Long; Vangavaragu, Jhansi Rani; Yan, Shijun; Hu, Gang; Guo, Lan; Rabinowitz, Molly; Glaser, Elzbieta; Arancio, Ottavio; Sosunov, Alexander A.; McKhann, Guy M.; Chen, John Xi; Yan, Shirley ShiDu

    2015-01-01

    Accumulation of amyloid-β (Aβ) in synaptic mitochondria is associated with mitochondrial and synaptic injury. The underlying mechanisms and strategies to eliminate Aβ and rescue mitochondrial and synaptic defects remain elusive. Presequence protease (PreP), a mitochondrial peptidasome, is a novel mitochondrial Aβ degrading enzyme. Here, we demonstrate for the first time that increased expression of active human PreP in cortical neurons attenuates Alzheimer disease's (AD)-like mitochondrial amyloid pathology and synaptic mitochondrial dysfunction, and suppresses mitochondrial oxidative stress. Notably, PreP-overexpressed AD mice show significant reduction in the production of proinflammatory mediators. Accordingly, increased neuronal PreP expression improves learning and memory and synaptic function in vivo AD mice, and alleviates Aβ-mediated reduction of long-term potentiation (LTP). Our results provide in vivo evidence that PreP may play an important role in maintaining mitochondrial integrity and function by clearance and degradation of mitochondrial Aβ along with the improvement in synaptic and behavioral function in AD mouse model. Thus, enhancing PreP activity/expression may be a new therapeutic avenue for treatment of AD. PMID:26123488

  11. High Glucose Causes Human Cardiac Progenitor Cell Dysfunction by Promoting Mitochondrial Fission: Role of a GLUT1 Blocker.

    Science.gov (United States)

    Choi, He Yun; Park, Ji Hye; Jang, Woong Bi; Ji, Seung Taek; Jung, Seok Yun; Kim, Da Yeon; Kang, Songhwa; Kim, Yeon Ju; Yun, Jisoo; Kim, Jae Ho; Baek, Sang Hong; Kwon, Sang-Mo

    2016-07-01

    Cardiovascular disease is the most common cause of death in diabetic patients. Hyperglycemia is the primary characteristic of diabetes and is associated with many complications. The role of hyperglycemia in the dysfunction of human cardiac progenitor cells that can regenerate damaged cardiac tissue has been investigated, but the exact mechanism underlying this association is not clear. Thus, we examined whether hyperglycemia could regulate mitochondrial dynamics and lead to cardiac progenitor cell dysfunction, and whether blocking glucose uptake could rescue this dysfunction. High glucose in cardiac progenitor cells results in reduced cell viability and decreased expression of cell cycle-related molecules, including CDK2 and cyclin E. A tube formation assay revealed that hyperglycemia led to a significant decrease in the tube-forming ability of cardiac progenitor cells. Fluorescent labeling of cardiac progenitor cell mitochondria revealed that hyperglycemia alters mitochondrial dynamics and increases expression of fission-related proteins, including Fis1 and Drp1. Moreover, we showed that specific blockage of GLUT1 improved cell viability, tube formation, and regulation of mitochondrial dynamics in cardiac progenitor cells. To our knowledge, this study is the first to demonstrate that high glucose leads to cardiac progenitor cell dysfunction through an increase in mitochondrial fission, and that a GLUT1 blocker can rescue cardiac progenitor cell dysfunction and downregulation of mitochondrial fission. Combined therapy with cardiac progenitor cells and a GLUT1 blocker may provide a novel strategy for cardiac progenitor cell therapy in cardiovascular disease patients with diabetes.

  12. Cyclophilin D deficiency improves mitochondrial function and learning/memory in aging Alzheimer disease mouse model.

    Science.gov (United States)

    Du, Heng; Guo, Lan; Zhang, Wensheng; Rydzewska, Monika; Yan, Shidu

    2011-03-01

    Mitochondrial stress is one of the early features of Alzheimer disease (AD). Mitochondrial Aβ has been linked to mitochondrial toxicity. Our recent study demonstrated that cyclophilin D (CypD) mediated mitochondrial permeability transition pore (mPTP) is an important mechanism for neuronal and synaptic stress induced by both Aβ and oxidative stress. In transgenic AD-type mice overexpressing mutant amyloid precursor protein (APP) and Aβ (mAPP), CypD deficiency improves mitochondrial and synaptic function and learning/memory up to 12 months old. Here we provide evidence of the protective effects of CypD deficiency in aged AD mice (22-24 months). Cyp D deficient mAPP mice demonstrate less calcium-induced mitochondrial swelling, increased mitochondrial calcium uptake capacity, preserved mitochondrial respiratory function and improved spatial learning/memory even in old age (known to be the age for late stage AD pathology and synaptic dysfunction). These data demonstrate that abrogation of CypD results in persistent life-long protection against Aβ toxicity in an Alzheimer's disease mouse model, thereby suggesting that blockade of CypD may be of benefit for Alzheimer disease treatment. Copyright © 2009 Elsevier Inc. All rights reserved.

  13. Sulfatases and human disease.

    Science.gov (United States)

    Diez-Roux, Graciana; Ballabio, Andrea

    2005-01-01

    Sulfatases are a highly conserved family of proteins that cleave sulfate esters from a wide range of substrates. The importance of sulfatases in human metabolism is underscored by the presence of at least eight human monogenic diseases caused by the deficiency of individual sulfatases. Sulfatase activity requires a unique posttranslational modification, which is impaired in patients with multiple sulfatase deficiency (MSD) due to a mutation of the sulfatase modifying factor 1 (SUMF1). Here we review current knowledge and future perspectives on the evolution of the sulfatase gene family, on the role of these enzymes in human metabolism, and on new developments in the therapy of sulfatase deficiencies.

  14. Prolonged Fasting Identifies Skeletal Muscle Mitochondrial Dysfunction as Consequence Rather Than Cause of Human Insulin Resistance

    NARCIS (Netherlands)

    Hoeks, J.; Herpen, N.A.; Mensink, M.R.; Moonen-Kornips, E.; Beurden, van D.; Hesselink, M.K.C.; Schrauwen, P.

    2010-01-01

    OBJECTIVE-Type 2 diabetes and insulin resistance have been associated with mitochondrial dysfunction, but it is debated whether this is a primary factor in the pathogenesis of the disease. To test the concept that mitochondrial dysfunction is secondary to the development of insulin resistance, we

  15. ATM-mediated mitochondrial damage response triggered by nuclear DNA damage in normal human lung fibroblasts.

    Science.gov (United States)

    Shimura, Tsutomu; Sasatani, Megumi; Kawai, Hidehiko; Kamiya, Kenji; Kobayashi, Junya; Komatsu, Kenshi; Kunugita, Naoki

    2017-11-03

    Ionizing radiation (IR) elevates mitochondrial oxidative phosphorylation (OXPHOS) in response to the energy requirement for DNA damage responses. Reactive oxygen species (ROS) released during mitochondrial OXPHOS may cause oxidative damage to mitochondria in irradiated cells. In this paper, we investigated the association between nuclear DNA damage and mitochondrial damage following IR in normal human lung fibroblasts. In contrast to low-doses of acute single radiation, continuous exposure of chronic radiation or long-term exposure of fractionated radiation (FR) induced persistent Rad51 and γ-H2AX foci at least 24 hours after IR in irradiated cells. Additionally, long-term FR increased mitochondrial ROS accompanied with enhanced mitochondrial membrane potential (ΔΨm) and mitochondrial complex IV (cytochrome c oxidase) activity. Mitochondrial ROS released from the respiratory chain complex I caused oxidative damage to mitochondria. Inhibition of ATM kinase or ATM loss eliminated nuclear DNA damage recognition and mitochondrial radiation responses. Consequently, nuclear DNA damage activates ATM which in turn increases ROS level and subsequently induces mitochondrial damage in irradiated cells. In conclusion, we demonstrated that ATM is essential in the mitochondrial radiation responses in irradiated cells. We further demonstrated that ATM is involved in signal transduction from nucleus to the mitochondria in response to IR.

  16. Extremely low frequency electromagnetic fields affect proliferation and mitochondrial activity of human cancer cell lines.

    Science.gov (United States)

    Destefanis, Michele; Viano, Marta; Leo, Christian; Gervino, Gianpiero; Ponzetto, Antonio; Silvagno, Francesca

    2015-01-01

    To date, the effects of electromagnetic fields on cell metabolism have been overlooked. The objective of the present study was to investigate the influence of extremely low frequency electromagnetic fields (ELF-EMF) over mitochondrial metabolism and the consequent impact on cancer cell growth. The effects of ELF-EMF on cancer growth were investigated in several human cancer cell lines by crystal violet assay. The modulation of mitochondrial activity was assessed by cytofluorimetric evaluation of membrane potential and by real-time quantification of mitochondrial transcription. Moreover the expression of several mitochondrial proteins and their levels in the organelle were evaluated. The long-term exposure to ELF-EMF reduced the proliferation of several cancer cell lines and the effect was associated to an increased mitochondrial activity without evident changes in ATP levels. The results of our experiments excluded a transcriptional modulation of mitochondrial respiratory complexes, rather suggesting that ELF-EMF increased the energy demand. The altered mitochondrial metabolism led to changes in mitochondrial protein profile. In fact we found a downregulated expression of mitochondrial phospho-ERK, p53 and cytochrome c. The results of the present study indicate that ELF-EMF can negatively modulate cancer cell growth increasing respiratory activity of cells and altering mitochondrial protein expression.

  17. Fragmentary 5S rRNA gene in the human mitochondrial genome

    Energy Technology Data Exchange (ETDEWEB)

    Nierlich, D.P.

    1982-02-01

    The human mitochondrial genoma contains a 23-nucleodtide sequence that is homologous to a part of the 5S rRNA's of bacteria. This homology, the structure of the likely transcript, and the location of the sequence relative to the mitochondrial rRNA genes suggest that the sequence represents a fragmentary 5S rRNA gene.

  18. Biomarkers of mitochondrial content in skeletal muscle of healthy young human subjects

    DEFF Research Database (Denmark)

    Larsen, Steen; Nielsen, Joachim; Neigaard Nielsen, Christina

    2012-01-01

    Skeletal muscle mitochondrial content varies extensively between human subjects. Biochemical measures of mitochondrial proteins, enzyme activities and lipids are often used as markers of mitochondrial content and muscle oxidative capacity (OXPHOS). The purpose of this study was to determine how...... closely associated these commonly used biochemical measures are to muscle mitochondrial content and muscle oxidative capacity (OXPHOS).Sixteen young healthy male subjects were recruited for this study. Subjects completed a graded exercise test to determine maximal oxygen uptake (VO(2peak)) and muscle......, mitochondrial DNA content, complex I-V protein content, and complex I-IV activity. Spearman correlation coefficient tests and Lin's concordance tests were applied to assess the absolute and relative association between the markers and mitochondrial content or OXPHOS.Subjects had a large range in VO(2peak...

  19. Fasciculations in human hereditary disease.

    Science.gov (United States)

    Finsterer, Josef; Aliyev, Rahim

    2015-06-01

    Fasciculations are a manifestation of peripheral nerve hyperexcitability in addition to myokymia, neuromyotonia, cramps, or tetany. Fasciculations occur in hereditary and non-hereditary diseases. Among the hereditary diseases, fasciculations are most frequently reported in familial amyotrophic lateral sclerosis (FALS), and spinal muscular atrophy (SMA). Among the non-hereditary diseases, fasciculations occur most frequently in peripheral nerve hyperexcitability syndromes (Isaac's syndrome, voltage-gated potassium channelopathy, cramp fasciculation syndrome, Morvan syndrome). If the cause of fasciculations remains unknown, they are called benign. Systematically reviewing the literature about fasciculations in hereditary disease shows that fasciculations can be a phenotypic feature in bulbospinal muscular atrophy (BSMA), GM2-gangliosidosis, triple-A syndrome, or hereditary neuropathy. Additionally, fasciculations have been reported in familial amyloidosis, spinocerebellar ataxias, Huntington's disease, Rett syndrome, central nervous system disease due to L1-cell adhesion molecule (L1CAM) mutations, Fabry's disease, or Gerstmann-Sträussler disease. Rarely, fasciculations may be a phenotypic feature in patients with mitochondrial disorders or other myopathies. Fasciculations are part of the phenotype in much more genetic disorders than commonly assumed. Fasciculations not only occur in motor neuron disease, but also in hereditary neuropathy, spinocerebellar ataxia, GM2-gangliosidosis, Huntington's disease, Rett syndrome, Fabry's disease, Gerstmann-Sträussler disease, mitochondrial disorders, or muscular dystrophies.

  20. Mitochonic Acid 5 (MA-5 Facilitates ATP Synthase Oligomerization and Cell Survival in Various Mitochondrial Diseases

    Directory of Open Access Journals (Sweden)

    Tetsuro Matsuhashi

    2017-06-01

    Full Text Available Mitochondrial dysfunction increases oxidative stress and depletes ATP in a variety of disorders. Several antioxidant therapies and drugs affecting mitochondrial biogenesis are undergoing investigation, although not all of them have demonstrated favorable effects in the clinic. We recently reported a therapeutic mitochondrial drug mitochonic acid MA-5 (Tohoku J. Exp. Med., 2015. MA-5 increased ATP, rescued mitochondrial disease fibroblasts and prolonged the life span of the disease model “Mitomouse” (JASN, 2016. To investigate the potential of MA-5 on various mitochondrial diseases, we collected 25 cases of fibroblasts from various genetic mutations and cell protective effect of MA-5 and the ATP producing mechanism was examined. 24 out of the 25 patient fibroblasts (96% were responded to MA-5. Under oxidative stress condition, the GDF-15 was increased and this increase was significantly abrogated by MA-5. The serum GDF-15 elevated in Mitomouse was likewise reduced by MA-5. MA-5 facilitates mitochondrial ATP production and reduces ROS independent of ETC by facilitating ATP synthase oligomerization and supercomplex formation with mitofilin/Mic60. MA-5 reduced mitochondria fragmentation, restores crista shape and dynamics. MA-5 has potential as a drug for the treatment of various mitochondrial diseases. The diagnostic use of GDF-15 will be also useful in a forthcoming MA-5 clinical trial.

  1. RCAN1 overexpression promotes age-dependent mitochondrial dysregulation related to neurodegeneration in Alzheimer's disease.

    Science.gov (United States)

    Wong, Helen; Levenga, Josien; Cain, Peter; Rothermel, Beverly; Klann, Eric; Hoeffer, Charles

    2015-12-01

    Aging is the largest risk factor for Alzheimer's disease (AD). Patients with Down syndrome (DS) develop symptoms consistent with early-onset AD, suggesting that overexpression of chromosome 21 genes such as Regulator of Calcineurin 1 (RCAN1) plays a role in AD pathogenesis. RCAN1 levels are increased in the brain of DS and AD patients but also in the human brain with normal aging. RCAN1 has been implicated in several neuronal functions, but whether its increased expression is correlative or causal in the aging-related progression of AD remains elusive. We show that brain-specific overexpression of the human RCAN1.1S isoform in mice promotes early age-dependent memory and synaptic plasticity deficits, tau pathology, and dysregulation of dynamin-related protein 1 (DRP1) activity associated with mitochondrial dysfunction and oxidative stress, reproducing key AD features. Based on these findings, we propose that chronic RCAN1 overexpression during aging alters DRP1-mediated mitochondrial fission and thus acts to promote AD-related progressive neurodegeneration.

  2. PINK1/Parkin-Dependent Mitochondrial Surveillance: From Pleiotropy to Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Olga Corti

    2017-05-01

    Full Text Available Parkinson's disease (PD is one of the most frequent neurodegenerative disease caused by the preferential, progressive degeneration of the dopaminergic (DA neurons of the substantia nigra (SN pars compacta. PD is characterized by a multifaceted pathological process involving protein misfolding, mitochondrial dysfunction, neuroinflammation and metabolism deregulation. The molecular mechanisms governing the complex interplay between the different facets of this process are still unknown. PARK2/Parkin and PARK6/PINK1, two genes responsible for familial forms of PD, act as a ubiquitous core signaling pathway, coupling mitochondrial stress to mitochondrial surveillance, by regulating mitochondrial dynamics, the removal of damaged mitochondrial components by mitochondria-derived vesicles, mitophagy, and mitochondrial biogenesis. Over the last decade, PINK1/Parkin-dependent mitochondrial quality control emerged as a pleiotropic regulatory pathway. Loss of its function impinges on a number of physiological processes suspected to contribute to PD pathogenesis. Its role in the regulation of innate immunity and inflammatory processes stands out, providing compelling support to the contribution of non-cell-autonomous immune mechanisms in PD. In this review, we illustrate the central role of this multifunctional pathway at the crossroads between mitochondrial stress, neuroinflammation and metabolism. We discuss how its dysfunction may contribute to PD pathogenesis and pinpoint major unresolved questions in the field.

  3. Mitochondrial Ca2+ uptake in skeletal muscle health and disease

    CERN Document Server

    Zhou, Jingsong; Yi, Jianxun

    2016-01-01

    Muscle uses Ca2+ as a messenger to control contraction and relies on ATP to maintain the intracellular Ca2+ homeostasis. Mitochondria are the major sub-cellular organelle of ATP production. With a negative inner membrane potential, mitochondria take up Ca2+ from their surroundings, a process called mitochondrial Ca2+ uptake. Under physiological conditions, Ca2+ uptake into mitochondria promotes ATP production. Excessive uptake causes mitochondrial Ca2+ overload, which activates downstream adverse responses leading to cell dysfunction. Moreover, mitochondrial Ca2+ uptake could shape spatio-temporal patterns of intracellular Ca2+ signaling. Malfunction of mitochondrial Ca2+ uptake is implicated in muscle degeneration. Unlike non-excitable cells, mitochondria in muscle cells experience dramatic changes of intracellular Ca2+ levels. Besides the sudden elevation of Ca2+ level induced by action potentials, Ca2+ transients in muscle cells can be as short as a few milliseconds during a single twitch or as long as min...

  4. Linking telomere loss and mitochondrial dysfunction in chronic disease

    DEFF Research Database (Denmark)

    Gonzalez-Ebsen, Ana Carlota; Gregersen, Niels; Olsen, Rikke Kj

    2017-01-01

    Telomeres and mitochondria are known to deteriorate over time. Telomere shortening is associated with aging, early senescence, and premature cell death. Mitochondrial dysfunction produces indiscriminate amounts of reactive oxygen species that may lead to oxidative damage to cellular constituents,...

  5. Mitochondrial Disease as a Cause of Neonatal Hemophagocytic Lymphohistiocytosis

    Directory of Open Access Journals (Sweden)

    Kazumasa Fuwa

    2016-01-01

    Full Text Available Diagnosis of mitochondrial respiratory chain disorder (MRCD is often difficult. Its pathogenesis is still unclear. We diagnosed MRCD by measuring the activity of the mitochondrial respiratory chain enzyme, and the patient also had hemophagocytic lymphohistiocytosis (HLH. A preterm female infant was born at 34 weeks of gestation. On day 6, HLH was revealed by bone marrow aspiration. She died on day 10 due to uncontrollable HLH. An autopsy was performed, and we measured the activity of the mitochondrial respiratory chain enzyme in the liver, muscle, and heart. The activity of complex I was decreased in all tissues. As we could not prove another origin of the HLH, she was diagnosed as having HLH caused by MRCD. It is useful to measure the activity of the mitochondrial respiratory chain enzyme for diagnosing MRCD. MRCD, which has a severe clinical course, may be related to HLH.

  6. Plasticity in mitochondrial cristae density allows metabolic capacity modulation in human skeletal muscle

    DEFF Research Database (Denmark)

    Nielsen, Joachim; Gejl, Kasper D; Hey-Mogensen, Martin

    2017-01-01

    , in human skeletal muscle, contrary to the current view, the mitochondrial cristae density is not constant, but exhibits plasticity with long-term endurance training. Furthermore, we show that frequently recruited mitochondria-enriched fibres have significantly increased cristae density and that, at whole......Mitochondrial energy production involves the movement of protons down a large electrochemical gradient through ATP synthase located on the folded inner membrane, known as cristae. In mammalian skeletal muscle, the density of cristae in mitochondria is thought to be constant. However, recent......-body level, muscle mitochondrial cristae density is a better predictor of maximal oxygen uptake rate than muscle mitochondrial volume. Our findings establish elevating mitochondrial cristae density as a regulatory mechanism for increasing metabolic power in human skeletal muscle. We propose...

  7. Mitochondrial dysfunction and cell death in neurodegenerative diseases through nitroxidative stress.

    Science.gov (United States)

    Akbar, Mohammed; Essa, Musthafa Mohamed; Daradkeh, Ghazi; Abdelmegeed, Mohamed A; Choi, Youngshim; Mahmood, Lubna; Song, Byoung-Joon

    2016-04-15

    Mitochondria are important for providing cellular energy ATP through the oxidative phosphorylation pathway. They are also critical in regulating many cellular functions including the fatty acid oxidation, the metabolism of glutamate and urea, the anti-oxidant defense, and the apoptosis pathway. Mitochondria are an important source of reactive oxygen species leaked from the electron transport chain while they are susceptible to oxidative damage, leading to mitochondrial dysfunction and tissue injury. In fact, impaired mitochondrial function is commonly observed in many types of neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, Huntington's disease, alcoholic dementia, brain ischemia-reperfusion related injury, and others, although many of these neurological disorders have unique etiological factors. Mitochondrial dysfunction under many pathological conditions is likely to be promoted by increased nitroxidative stress, which can stimulate post-translational modifications (PTMs) of mitochondrial proteins and/or oxidative damage to mitochondrial DNA and lipids. Furthermore, recent studies have demonstrated that various antioxidants, including naturally occurring flavonoids and polyphenols as well as synthetic compounds, can block the formation of reactive oxygen and/or nitrogen species, and thus ultimately prevent the PTMs of many proteins with improved disease conditions. Therefore, the present review is aimed to describe the recent research developments in the molecular mechanisms for mitochondrial dysfunction and tissue injury in neurodegenerative diseases and discuss translational research opportunities. Published by Elsevier B.V.

  8. Age-associated mitochondrial DNA mutations lead to small but significant changes in cell proliferation and apoptosis in human colonic crypts.

    NARCIS (Netherlands)

    Nooteboom, M.; Johnson, R.; Taylor, R.W.; Wright, N.A.; Lightowlers, R.N.; Kirkwood, T.B.; Mathers, J.C.; Turnbull, D.M.; Greaves, L.C.

    2010-01-01

    Mitochondrial DNA (mtDNA) mutations are a cause of human disease and are proposed to have a role in human aging. Clonally expanded mtDNA point mutations have been detected in replicating tissues and have been shown to cause respiratory chain (RC) defects. The effect of these mutations on other

  9. Characteristics of intestinal pseudo-obstruction in patients with mitochondrial diseases

    Science.gov (United States)

    Sekino, Yusuke; Inamori, Masahiko; Yamada, Eiji; Ohkubo, Hidenori; Sakai, Eiji; Higurashi, Takuma; Iida, Hiroshi; Hosono, Kunihiro; Endo, Hiroki; Nonaka, Takashi; Takahashi, Hirokazu; Koide, Tomoko; Abe, Yasunobu; Gotoh, Eiji; Koyano, Shigeru; Kuroiwa, Yoshiyuki; Maeda, Shin; Nakajima, Atsushi

    2012-01-01

    AIM: To reveal the frequency, characteristics and prog-nosis of chronic intestinal pseudo-obstruction (CIP) in mitochondrial disease patients. METHODS: Between January 2000 and December 2010, 31 patients (13 males and 18 females) were diagnosed with mitochondrial diseases at our hospital. We conducted a retrospective review of the patients’ sex, subclass of mitochondrial disease, age at onset of mitochondrial disease, frequency of CIP and the age at its onset, and the duration of survival. The age at onset or at the first diagnosis of the disorder that led to the clinical suspicion of mitochondrial disease was also examined. RESULTS: Twenty patients were sub-classified with mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS), 8 with chronic progressive external ophthalmoplegia (CPEO), and 3 with myoclonus epilepsy associated with ragged-red fibers (MERRF). Nine patients were diagnosed with CIP, 8 of the 20 (40.0%) patients with MELAS, 0 of the 8 (0.0%) patients with CPEO, and 1 of the 3 (33.3%) patients with MERRF. The median age (range) at the diagnosis and the median age at onset of mitochondrial disease were 40 (17-69) and 25 (12-63) years in patients with CIP, and 49 (17-81) and 40 (11-71) years in patients without CIP. During the survey period, 5 patients (4 patients with MELAS and 1 with CPEO) died. The cause of death was cardiomyopathy in 2 patients with MELAS, cerebral infarction in 1 patient with MELAS, epilepsy and aspiration pneumonia in 1 patient with MELAS, and multiple metastases from gastric cancer and aspiration pneumonia in 1 patient with CPEO. CONCLUSION: Patients with CIP tend to have disorders that are suspected to be related to mitochondrial diseases at younger ages than are patients without CIP. PMID:22969229

  10. Mitochondrial reactive oxygen species are scavenged by Cockayne syndrome B protein in human fibroblasts without nuclear DNA damage.

    Science.gov (United States)

    Cleaver, James E; Brennan-Minnella, Angela M; Swanson, Raymond A; Fong, Ka-wing; Chen, Junjie; Chou, Kai-ming; Chen, Yih-wen; Revet, Ingrid; Bezrookove, Vladimir

    2014-09-16

    Cockayne syndrome (CS) is a human DNA repair-deficient disease that involves transcription coupled repair (TCR), in which three gene products, Cockayne syndrome A (CSA), Cockayne syndrome B (CSB), and ultraviolet stimulated scaffold protein A (UVSSA) cooperate in relieving RNA polymerase II arrest at damaged sites to permit repair of the template strand. Mutation of any of these three genes results in cells with increased sensitivity to UV light and defective TCR. Mutations in CSA or CSB are associated with severe neurological disease but mutations in UVSSA are for the most part only associated with increased photosensitivity. This difference raises questions about the relevance of TCR to neurological disease in CS. We find that CSB-mutated cells, but not UVSSA-deficient cells, have increased levels of intramitochondrial reactive oxygen species (ROS), especially when mitochondrial complex I is inhibited by rotenone. Increased ROS would result in oxidative damage to mitochondrial proteins, lipids, and DNA. CSB appears to behave as an electron scavenger in the mitochondria whose absence leads to increased oxidative stress. Mitochondrial ROS, however, did not cause detectable nuclear DNA damage even when base excision repair was blocked by an inhibitor of polyADP ribose polymerase. Neurodegeneration in Cockayne syndrome may therefore be associated with ROS-induced damage in the mitochondria, independent of nuclear TCR. An implication of our present results is that mitochondrial dysfunction involving ROS has a major impact on CS-B pathology, whereas nuclear TCR may have a minimal role.

  11. High Glucose Causes Human Cardiac Progenitor Cell Dysfunction by Promoting Mitochondrial Fission: Role of a GLUT1 Blocker

    OpenAIRE

    Choi, He Yun; Park, Ji Hye; Jang, Woong Bi; Ji, Seung Taek; Jung, Seok Yun; Kim, Da Yeon; Kang, Songhwa; Kim, Yeon Ju; Yun, Jisoo; Kim, Jae Ho; Baek, Sang Hong; Kwon, Sang-Mo

    2016-01-01

    Cardiovascular disease is the most common cause of death in diabetic patients. Hyperglycemia is the primary characteristic of diabetes and is associated with many complications. The role of hyperglycemia in the dysfunction of human cardiac progenitor cells that can regenerate damaged cardiac tissue has been investigated, but the exact mechanism underlying this association is not clear. Thus, we examined whether hyperglycemia could regulate mitochondrial dynamics and lead to cardiac progenitor...

  12. Mitochondrial Molecular Markers for Resistance to Bayoud Disease in Date Palm.

    Science.gov (United States)

    Saleh, Amgad A; Sharafaddin, Anwar H; El-Komy, Mahmoud H; Ibrahim, Yasser E; Hamad, Younis K; Molan, Younis Y

    2017-01-01

    Bayoud disease, caused by Fusarium oxysporum f. sp. albedinis, is a very serious and destructive disease to date palm. Screening of date palm germplasm for resistance to bayoud disease is a crucial step to avoid or alleviate the disease consequences. Fortunately, it was discovered that there are two mitochondrial plasmid-like DNA molecules associated with susceptibility or resistance to bayoud disease. In this chapter, we present a fast, simple, and reliable technique to screen date palm germplasm for the presence of these mitochondrial molecular markers associated with susceptibility or resistance to bayoud.

  13. HmtDB 2016: data update, a better performing query system and human mitochondrial DNA haplogroup predictor.

    Science.gov (United States)

    Clima, Rosanna; Preste, Roberto; Calabrese, Claudia; Diroma, Maria Angela; Santorsola, Mariangela; Scioscia, Gaetano; Simone, Domenico; Shen, Lishuang; Gasparre, Giuseppe; Attimonelli, Marcella

    2017-01-04

    The HmtDB resource hosts a database of human mitochondrial genome sequences from individuals with healthy and disease phenotypes. The database is intended to support both population geneticists as well as clinicians undertaking the task to assess the pathogenicity of specific mtDNA mutations. The wide application of next-generation sequencing (NGS) has provided an enormous volume of high-resolution data at a low price, increasing the availability of human mitochondrial sequencing data, which called for a cogent and significant expansion of HmtDB data content that has more than tripled in the current release. We here describe additional novel features, including: (i) a complete, user-friendly restyling of the web interface, (ii) links to the command-line stand-alone and web versions of the MToolBox package, an up-to-date tool to reconstruct and analyze human mitochondrial DNA from NGS data and (iii) the implementation of the Reconstructed Sapiens Reference Sequence (RSRS) as mitochondrial reference sequence. The overall update renders HmtDB an even more handy and useful resource as it enables a more rapid data access, processing and analysis. HmtDB is accessible at http://www.hmtdb.uniba.it/. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  14. Proteomic approaches to identify and characterize alterations to the mitochondrial proteome in alcoholic liver disease.

    Science.gov (United States)

    Bailey, Shannon M; Andringa, Kelly K; Landar, Aimee; Darley-Usmar, Victor M

    2008-01-01

    Mitochondrial dysfunction is recognized as a contributing factor to a number of diseases, including chronic alcohol-induced hepatotoxicity. Although there is a detailed understanding of the metabolic pathways and proteins of the liver mitochondrion, little is known of how changes in the mitochondrial proteome contribute to the development of hepatic pathologies. In this short overview the insights gained from study of changes in the mitochondrial proteome in alcoholic liver disease will be described. Profiling the liver mitochondrial proteome has the potential to shed light on the alcohol-mediated molecular defects responsible for mitochondrial and cellular dysfunction. The methods presented herein demonstrate the power of using complementary proteomics approaches, that is, 2-D IEF/SDS-PAGE and BN-PAGE, to identify changes in the abundance of mitochondrial proteins after chronic alcohol consumption. These proteomic data can then be integrated into a logical and mechanistic framework to further our understanding of the role of mitochondrial dysfunction in the pathogenesis of alcohol-induced liver disease.

  15. Redox metabolism abnormalities in autistic children associated with mitochondrial disease

    Science.gov (United States)

    Frye, R E; DeLaTorre, R; Taylor, H; Slattery, J; Melnyk, S; Chowdhury, N; James, S J

    2013-01-01

    Research studies have uncovered several metabolic abnormalities associated with autism spectrum disorder (ASD), including mitochondrial disease (MD) and abnormal redox metabolism. Despite the close connection between mitochondrial dysfunction and oxidative stress, the relation between MD and oxidative stress in children with ASD has not been studied. Plasma markers of oxidative stress and measures of cognitive and language development and ASD behavior were obtained from 18 children diagnosed with ASD who met criteria for probable or definite MD per the Morava et al. criteria (ASD/MD) and 18 age and gender-matched ASD children without any biological markers or symptoms of MD (ASD/NoMD). Plasma measures of redox metabolism included reduced free glutathione (fGSH), oxidized glutathione (GSSG), the fGSH/GSSG ratio and 3-nitrotyrosine (3NT). In addition, a plasma measure of chronic immune activation, 3-chlorotyrosine (3CT), was also measured. Language was measured using the preschool language scale or the expressive one-word vocabulary test (depending on the age), adaptive behaviour was measured using the Vineland Adaptive Behavior Scale (VABS) and core autism symptoms were measured using the Autism Symptoms Questionnaire and the Social Responsiveness Scale. Children with ASD/MD were found to have lower scores on the communication and daily living skill subscales of the VABS despite having similar language and ASD symptoms. Children with ASD/MD demonstrated significantly higher levels of fGSH/GSSG and lower levels of GSSG as compared with children with ASD/NoMD, suggesting an overall more favourable glutathione redox status in the ASD/MD group. However, compare with controls, both ASD groups demonstrated lower fGSH and fGSH/GSSG, demonstrating that both groups suffer from redox abnormalities. Younger ASD/MD children had higher levels of 3CT than younger ASD/NoMD children because of an age-related effect in the ASD/MD group. Both ASD groups demonstrated significantly

  16. Adult-onset Mendelian PEO Associated with Mitochondrial Disease.

    Science.gov (United States)

    Sommerville, Ewen W; Chinnery, Patrick F; Gorman, Gráinne S; Taylor, Robert W

    2014-01-01

    Progressive external ophthalmoplegia (PEO) is an eye movement disorder characterised by paresis of the extra ocular muscles and muscle restricted multiple mitochondrial DNA (mtDNA) deletions. Classification of patients is particularly difficult due to overlapping phenotypes and a poor genotype-phenotype relationship. Despite the identification of several nuclear encoded genes causing PEO, over half of patients with clinically confirmed PEO do not have a genetic diagnosis. To systematically review genotypic and phenotypic correlates of published cases of adult-onset PEO. Patients were identified from interrogation of articles from Scopus, Medline via PubMed, and Genetic Abstracts databases using electronic searches (1st January 1970 to 8th November 2013). Reference lists and UniProt entries were also manually checked for additional articles. Twelve nuclear encoded genes were identified (TYMP, SLC25A4, POLG, C10ORF2, OPA1, POLG2, RRM2B, TK2, DGUOK, MPV17, MGME1, and DNA2) systematically from 583 patients. At the time of writing, mutations in SPG7 and AFG3L2 genes were reported to be associated with ophthalmoparesis and multiple mtDNA deletions in fourteen additional adult-onset PEO patients, bringing the total number of known genes to fourteen. Diagnostic yield is still critically dependent on the meticulous clinical and biochemical characterisation of patients. Understanding the intimate relationship between genotype and phenotype remains a fundamental challenge. The results of this systematic review provide guidance to both patients and clinician about future prognosis, and will serve, in future, to assess methods of disease prevention and evaluation of targeted therapeutic strategies.

  17. Proteinopathy, oxidative stress and mitochondrial dysfunction: cross talk in Alzheimer's disease and Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Ganguly G

    2017-03-01

    Full Text Available Gargi Ganguly,1 Sasanka Chakrabarti,2 Uttara Chatterjee,1 Luciano Saso3 1Department of Pathology, Institute of Post Graduate Medical Education and Research, Kolkata, 2Department of Biochemistry, ICARE Institute of Medical Sciences and Research, Haldia, West Bengal, India; 3Department of Physiology and Pharmacology “Vittorio Erspamer”, Sapienza University of Rome, Rome, Italy Abstract: Alzheimer’s disease and Parkinson’s disease are two common neurodegenerative diseases of the elderly people that have devastating effects in terms of morbidity and mortality. The predominant form of the disease in either case is sporadic with uncertain etiology. The clinical features of Parkinson’s disease are primarily motor deficits, while the patients of Alzheimer’s disease present with dementia and cognitive impairment. Though neuronal death is a common element in both the disorders, the postmortem histopathology of the brain is very characteristic in each case and different from each other. In terms of molecular pathogenesis, however, both the diseases have a significant commonality, and proteinopathy (abnormal accumulation of misfolded proteins, mitochondrial dysfunction and oxidative stress are the cardinal features in either case. These three damage mechanisms work in concert, reinforcing each other to drive the pathology in the aging brain for both the diseases; very interestingly, the nature of interactions among these three damage mechanisms is very similar in both the diseases, and this review attempts to highlight these aspects. In the case of Alzheimer’s disease, the peptide amyloid beta (Aβ is responsible for the proteinopathy, while α-synuclein plays a similar role in Parkinson’s disease. The expression levels of these two proteins and their aggregation processes are modulated by reactive oxygen radicals and transition metal ions in a similar manner. In turn, these proteins – as oligomers or in aggregated forms – cause

  18. Inhibition of amyloid-beta (Abeta) peptide-binding alcohol dehydrogenase-Abeta interaction reduces Abeta accumulation and improves mitochondrial function in a mouse model of Alzheimer's disease.

    Science.gov (United States)

    Yao, Jun; Du, Heng; Yan, Shiqiang; Fang, Fang; Wang, Chaodong; Lue, Lih-Fen; Guo, Lan; Chen, Doris; Stern, David M; Gunn Moore, Frank J; Xi Chen, John; Arancio, Ottavio; Yan, Shirley ShiDu

    2011-02-09

    Amyloid-β (Aβ) peptide-binding alcohol dehydrogenase (ABAD), an enzyme present in neuronal mitochondria, exacerbates Aβ-induced cell stress. The interaction of ABAD with Aβ exacerbates Aβ-induced mitochondrial and neuronal dysfunction. Here, we show that inhibition of the ABAD-Aβ interaction, using a decoy peptide (DP) in vitro and in vivo, protects against aberrant mitochondrial and neuronal function and improves spatial learning/memory. Intraperitoneal administration of ABAD-DP [fused to the transduction of human immunodeficiency virus 1-transactivator (Tat) protein and linked to the mitochondrial targeting sequence (Mito) (TAT-mito-DP) to transgenic APP mice (Tg mAPP)] blocked formation of ABAD-Aβ complex in mitochondria, increased oxygen consumption and enzyme activity associated with the mitochondrial respiratory chain, attenuated mitochondrial oxidative stress, and improved spatial memory. Similar protective effects were observed in Tg mAPP mice overexpressing neuronal ABAD decoy peptide (Tg mAPP/mito-ABAD). Notably, inhibition of the ABAD-Aβ interaction significantly reduced mitochondrial Aβ accumulation. In parallel, the activity of mitochondrial Aβ-degrading enzyme PreP (presequence peptidase) was enhanced in Tg mAPP mitochondria expressing the ABAD decoy peptide. These data indicate that segregating ABAD from Aβ protects mitochondria/neurons from Aβ toxicity; thus, ABAD-Aβ interaction is an important mechanism underlying Aβ-mediated mitochondrial and neuronal perturbation. Inhibitors of ABAD-Aβ interaction may hold promise as targets for the prevention and treatment of Alzheimer's disease.

  19. Inhibition of Amyloid-β (Aβ) Peptide-Binding Alcohol Dehydrogenase-Aβ Interaction Reduces Aβ Accumulation and Improves Mitochondrial Function in a Mouse Model of Alzheimer's Disease

    Science.gov (United States)

    Yao, Jun; Du, Heng; Yan, Shiqiang; Fang, Fang; Wang, Chaodong; Lue, Lih-Fen; Guo, Lan; Chen, Doris; Stern, David M.; Gunn Moore, Frank J.; Xi Chen, John; Arancio, Ottavio

    2011-01-01

    Amyloid-β (Aβ) peptide-binding alcohol dehydrogenase (ABAD), an enzyme present in neuronal mitochondria, exacerbates Aβ-induced cell stress. The interaction of ABAD with Aβ exacerbates Aβ-induced mitochondrial and neuronal dysfunction. Here, we show that inhibition of the ABAD-Aβ interaction, using a decoy peptide (DP) in vitro and in vivo, protects against aberrant mitochondrial and neuronal function and improves spatial learning/memory. Intraperitoneal administration of ABAD-DP [fused to the transduction of human immunodeficiency virus 1-transactivator (Tat) protein and linked to the mitochondrial targeting sequence (Mito) (TAT-mito-DP) to transgenic APP mice (Tg mAPP)] blocked formation of ABAD-Aβ complex in mitochondria, increased oxygen consumption and enzyme activity associated with the mitochondrial respiratory chain, attenuated mitochondrial oxidative stress, and improved spatial memory. Similar protective effects were observed in Tg mAPP mice overexpressing neuronal ABAD decoy peptide (Tg mAPP/mito-ABAD). Notably, inhibition of the ABAD-Aβ interaction significantly reduced mitochondrial Aβ accumulation. In parallel, the activity of mitochondrial Aβ-degrading enzyme PreP (presequence peptidase) was enhanced in Tg mAPP mitochondria expressing the ABAD decoy peptide. These data indicate that segregating ABAD from Aβ protects mitochondria/neurons from Aβ toxicity; thus, ABAD-Aβ interaction is an important mechanism underlying Aβ-mediated mitochondrial and neuronal perturbation. Inhibitors of ABAD-Aβ interaction may hold promise as targets for the prevention and treatment of Alzheimer's disease. PMID:21307267

  20. Associations of mitochondrial haplogroups and mitochondrial DNA copy numbers with end-stage renal disease in a Han population.

    Science.gov (United States)

    Zhang, Yuheng; Zhao, Ying; Wen, Shuzhen; Yan, Rengna; Yang, Qinglan; Chen, Huimei

    2017-09-01

    Mitochondrial DNA (mtDNA) is closely related to mitochondrion function, and variations have been suggested to be involved in pathogenesis of complex diseases. The present study sought to elucidate mitochondrial haplogroups and mtDNA copy number in end-stage renal disease (ESRD) in a Han population. First, the mitochondrial haplogroups of 37 ESRD patients were clustered into several haplogroups, and haplogroup A & D were taken as the candidate risk haplogroups for ESRD. Second, the frequencies of A and D were assessed in 344 ESRD patients and 438 healthy controls, respectively. Haplogroup D was found to be risk maker for ESRD in young subjects (<30 years) with an OR of 2.274. Finally, intracellular and cell-free mtDNA copy numbers were evaluated with quantitative-PCR. The ESRD patients exhibited greater cell-free mtDNA contents than the healthy controls but less intracellular mtDNA. Haplogroup D exhibited a further increase in cell-free mtDNA content and a decrease in intracellular mtDNA content among the ESRDs patients. Our findings suggest that mtNDA haplogroup D may contributes to pathogenesis of early-onset ESRD through alterations of mtDNA copy numbers.

  1. Insertion near the mitochondrial tyrosine tRNA gene in patients with mitochondrial diseases

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Y.; Nonaka, I. [National Institute of Neuroscience, Tokyo (Japan); Horai, S. [National Institute of Genetics, Mishima (Japan)

    1994-09-01

    The 3243 mutation commonly found in patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) has been occasionally detected in patients with chronic progressive external opthalmoplegia (CPEO). To elucidate the molecular mechanism underlying this phenomenon, an extensive mitochondrial (mt) DNA study was performed on such a patient (3243-CPEO). The newly discovered insertion was located in the noncoding region between cytrochrome c oxidase subunit 1 and tyrosine tRNA. The insertion was not found in 58 or 22 CPEO patients with or without mtDNA large-scale deletion but in another 3243-CPEO patient. In addition, the insertion was present in 1 of 116 normal Japanese, who had no 3243 mutation, and in 3 of 68 3243-MELAS patients. These results raise the possibility that the phenotypic expression of the 3243 mutation could be modulated or arranged by additional mtDNA mutations.

  2. iPSC-derived neuronal models of PANK2-associated neurodegeneration reveal mitochondrial dysfunction contributing to early disease.

    Directory of Open Access Journals (Sweden)

    Charles Arber

    Full Text Available Mutations in PANK2 lead to neurodegeneration with brain iron accumulation. PANK2 has a role in the biosynthesis of coenzyme A (CoA from dietary vitamin B5, but the neuropathological mechanism and reasons for iron accumulation remain unknown. In this study, atypical patient-derived fibroblasts were reprogrammed into induced pluripotent stem cells (iPSCs and subsequently differentiated into cortical neuronal cells for studying disease mechanisms in human neurons. We observed no changes in PANK2 expression between control and patient cells, but a reduction in protein levels was apparent in patient cells. CoA homeostasis and cellular iron handling were normal, mitochondrial function was affected; displaying activated NADH-related and inhibited FADH-related respiration, resulting in increased mitochondrial membrane potential. This led to increased reactive oxygen species generation and lipid peroxidation in patient-derived neurons. These data suggest that mitochondrial deficiency is an early feature of the disease process and can be explained by altered NADH/FADH substrate supply to oxidative phosphorylation. Intriguingly, iron chelation appeared to exacerbate the mitochondrial phenotype in both control and patient neuronal cells. This raises caution for the use iron chelation therapy in general when iron accumulation is absent.

  3. Role of mitochondrial dysfunction and altered autophagy in cardiovascular aging and disease: from mechanisms to therapeutics

    Science.gov (United States)

    Marzetti, Emanuele; Csiszar, Anna; Dutta, Debapriya; Balagopal, Gauthami; Calvani, Riccardo

    2013-01-01

    Advanced age is associated with a disproportionate prevalence of cardiovascular disease (CVD). Intrinsic alterations in the heart and the vasculature occurring over the life course render the cardiovascular system more vulnerable to various stressors in late life, ultimately favoring the development of CVD. Several lines of evidence indicate mitochondrial dysfunction as a major contributor to cardiovascular senescence. Besides being less bioenergetically efficient, damaged mitochondria also produce increased amounts of reactive oxygen species, with detrimental structural and functional consequences for the cardiovascular system. The age-related accumulation of dysfunctional mitochondrial likely results from the combination of impaired clearance of damaged organelles by autophagy and inadequate replenishment of the cellular mitochondrial pool by mitochondriogenesis. In this review, we summarize the current knowledge about relevant mechanisms and consequences of age-related mitochondrial decay and alterations in mitochondrial quality control in the cardiovascular system. The involvement of mitochondrial dysfunction in the pathogenesis of cardiovascular conditions especially prevalent in late life and the emerging connections with neurodegeneration are also illustrated. Special emphasis is placed on recent discoveries on the role played by alterations in mitochondrial dynamics (fusion and fission), mitophagy, and their interconnections in the context of age-related CVD and endothelial dysfunction. Finally, we discuss pharmacological interventions targeting mitochondrial dysfunction to delay cardiovascular aging and manage CVD. PMID:23748424

  4. Mitochondrial trifunctional protein deficiency in human cultured fibroblasts

    DEFF Research Database (Denmark)

    Djouadi, Fatima; Habarou, Florence; Le Bachelier, Carole

    2016-01-01

    Mitochondrial trifunctional protein (MTP) deficiency caused by HADHA or HADHB gene mutations exhibits substantial molecular, biochemical, and clinical heterogeneity and ranks among the more severe fatty acid oxidation (FAO) disorders, without pharmacological treatment. Since bezafibrate has been ...

  5. A role for mitochondrial oxidants in stress-induced premature senescence of human vascular smooth muscle cells

    Directory of Open Access Journals (Sweden)

    Yogita Mistry

    2013-01-01

    Full Text Available Mitochondria are a major source of cellular oxidants and have been implicated in aging and associated pathologies, notably cardiovascular diseases. Vascular cell senescence is observed in experimental and human cardiovascular pathologies. Our previous data highlighted a role for angiotensin II in the induction of telomere-dependent and -independent premature senescence of human vascular smooth muscle cells and suggested this was due to production of superoxide by NADPH oxidase. However, since a role for mitochondrial oxidants was not ruled out we hypothesise that angiotensin II mediates senescence by mitochondrial superoxide generation and suggest that inhibition of superoxide may prevent vascular smooth muscle cell aging in vitro. Cellular senescence was induced using a stress-induced premature senescence protocol consisting of three successive once-daily exposure of cells to 1×10−8 mol/L angiotensin II and was dependent upon the type-1 angiotensin II receptor. Angiotensin stimulated NADPH-dependent superoxide production as estimated using lucigenin chemiluminescence in cell lysates and this was attenuated by the mitochondrial electron transport chain inhibitor, rotenone. Angiotensin also resulted in an increase in mitoSOX fluorescence indicating stimulation of mitochondrial superoxide. Significantly, the induction of senescence by angiotensin II was abrogated by rotenone and by the mitochondria-targeted superoxide dismutase mimetic, mitoTEMPO. These data suggest that mitochondrial superoxide is necessary for the induction of stress-induced premature senescence by angiotensin II and taken together with other data suggest that mitochondrial cross-talk with NADPH oxidases, via as yet unidentified signalling pathways, is likely to play a key role.

  6. AF-6 Protects Against Dopaminergic Dysfunction and Mitochondrial Abnormalities in Drosophila Models of Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Adeline H. Basil

    2017-08-01

    Full Text Available Afadin 6 (AF-6 is an F-actin binding multidomain-containing scaffolding protein that is known for its function in cell-cell adhesion. Interestingly, besides this well documented role, we recently found that AF-6 is a Parkin-interacting protein that augments Parkin/PINK1-mediated mitophagy. Notably, mutations in Parkin and PINK1 are causative of recessively inherited forms of Parkinson’s disease (PD and aberrant mitochondrial homeostasis is thought to underlie PD pathogenesis. Given the novel role of AF-6 in mitochondrial quality control (QC, we hypothesized that AF-6 overexpression may be beneficial to PD. Using the Drosophila melanogaster as a model system, we demonstrate in this study that transgenic overexpression of human AF-6 in parkin and also pink1 null flies rescues their mitochondrial pathology and associated locomotion deficit, which results in their improved survival over time. Similarly, AF-6 overexpression also ameliorates the pathological phenotypes in flies expressing the Leucine Rich Repeat Kinase 2 (LRRK2 G2019S mutant, a mutation that is associated with dominantly-inherited PD cases in humans. Conversely, when endogenous AF-6 expression is silenced, it aggravates the disease phenotypes of LRRK2 mutant flies. Aside from these genetic models, we also found that AF-6 overexpression is protective against the loss of dopaminergic neurons in flies treated with rotenone, a mitochondrial complex I inhibitor commonly used to generate animal models of PD. Taken together, our results demonstrate that AF-6 protects against dopaminergic dysfunction and mitochondrial abnormalities in multiple Drosophila models of PD, and suggest the therapeutic value of AF-6-related pathways in mitigating PD pathogenesis.

  7. Advances in the understanding of mitochondrial DNA as a pathogenic factor in inflammatory diseases [version 1; referees: 3 approved

    Directory of Open Access Journals (Sweden)

    Ray K. Boyapati

    2017-02-01

    Full Text Available Mitochondrial DNA (mtDNA has many similarities with bacterial DNA because of their shared common ancestry. Increasing evidence demonstrates mtDNA to be a potent danger signal that is recognised by the innate immune system and can directly modulate the inflammatory response. In humans, elevated circulating mtDNA is found in conditions with significant tissue injury such as trauma and sepsis and increasingly in chronic organ-specific and systemic illnesses such as steatohepatitis and systemic lupus erythematosus. In this review, we examine our current understanding of mtDNA-mediated inflammation and how the mechanisms regulating mitochondrial homeostasis and mtDNA release represent exciting and previously under-recognised important factors in many human inflammatory diseases, offering many new translational opportunities.

  8. Effect of DHA and CoenzymeQ10 Against Aβ- and Zinc-Induced Mitochondrial Dysfunction in Human Neuronal Cells

    Directory of Open Access Journals (Sweden)

    Nadia Sadli

    2013-07-01

    Full Text Available Background: Beta-amyloid (Aβ protein is a key factor in the pathogenesis of Alzheimer's disease (AD and it has been reported that mitochondria is involved in the biochemical pathway by which Aβ can lead to neuronal dysfunction. Coenzyme Q10 (CoQ10 is an essential cofactor involved in the mitochondrial electron transport chain and has been suggested as a potential therapeutic agent in AD. Zinc toxicity also affects cellular energy production by decreasing oxygen consumption rate (OCR and ATP turnover in human neuronal cells, which can be restored by the neuroprotective effect of docosahexaenoic acid (DHA. Method: In the present study, using Seahorse XF-24 Metabolic Flux Analysis we investigated the effect of DHA and CoQ10 alone and in combination against Aβ- and zinc-mediated changes in the mitochondrial function of M17 neuroblastoma cell line. Results: Here, we observed that DHA is specifically neuroprotective against zinc-triggered mitochondrial dysfunction, but does not directly affect Aβ neurotoxicity. CoQ10 has shown to be protective against both Aβ- and zinc-induced alterations in mitochondrial function. Conclusion: Our results indicate that DHA and CoQ10 may be useful for the prevention, treatment and management of neurodegenerative diseases such as AD.

  9. Abnormal mitochondrial transport and morphology as early pathological changes in human models of spinal muscular atrophy

    Directory of Open Access Journals (Sweden)

    Chong-Chong Xu

    2016-01-01

    Full Text Available Spinal muscular atrophy (SMA, characterized by specific degeneration of spinal motor neurons, is caused by mutations in the survival of motor neuron 1, telomeric (SMN1 gene and subsequent decreased levels of functional SMN. How the deficiency of SMN, a ubiquitously expressed protein, leads to spinal motor neuron-specific degeneration in individuals affected by SMA remains unknown. In this study, we examined the role of SMN in mitochondrial axonal transport and morphology in human motor neurons by generating SMA type 1 patient-specific induced pluripotent stem cells (iPSCs and differentiating these cells into spinal motor neurons. The initial specification of spinal motor neurons was not affected, but these SMA spinal motor neurons specifically degenerated following long-term culture. Moreover, at an early stage in SMA spinal motor neurons, but not in SMA forebrain neurons, the number of mitochondria, mitochondrial area and mitochondrial transport were significantly reduced in axons. Knocking down of SMN expression led to similar mitochondrial defects in spinal motor neurons derived from human embryonic stem cells, confirming that SMN deficiency results in impaired mitochondrial dynamics. Finally, the application of N-acetylcysteine (NAC mitigated the impairment in mitochondrial transport and morphology and rescued motor neuron degeneration in SMA long-term cultures. Furthermore, NAC ameliorated the reduction in mitochondrial membrane potential in SMA spinal motor neurons, suggesting that NAC might rescue apoptosis and motor neuron degeneration by improving mitochondrial health. Overall, our data demonstrate that SMN deficiency results in abnormal mitochondrial transport and morphology and a subsequent reduction in mitochondrial health, which are implicated in the specific degeneration of spinal motor neurons in SMA.

  10. Mitochondrial aquaporin-8 knockdown in human hepatoma HepG2 cells causes ROS-induced mitochondrial depolarization and loss of viability

    Energy Technology Data Exchange (ETDEWEB)

    Marchissio, Maria Julia; Francés, Daniel Eleazar Antonio; Carnovale, Cristina Ester; Marinelli, Raúl Alberto, E-mail: rmarinel@unr.edu.ar

    2012-10-15

    Human aquaporin-8 (AQP8) channels facilitate the diffusional transport of H{sub 2}O{sub 2} across membranes. Since AQP8 is expressed in hepatic inner mitochondrial membranes, we studied whether mitochondrial AQP8 (mtAQP8) knockdown in human hepatoma HepG2 cells impairs mitochondrial H{sub 2}O{sub 2} release, which may lead to organelle dysfunction and cell death. We confirmed AQP8 expression in HepG2 inner mitochondrial membranes and found that 72 h after cell transfection with siRNAs targeting two different regions of the human AQP8 molecule, mtAQP8 protein specifically decreased by around 60% (p < 0.05). Studies in isolated mtAQP8-knockdown mitochondria showed that H{sub 2}O{sub 2} release, assessed by Amplex Red, was reduced by about 45% (p < 0.05), an effect not observed in digitonin-permeabilized mitochondria. mtAQP8-knockdown cells showed an increase in mitochondrial ROS, assessed by dichlorodihydrofluorescein diacetate (+ 120%, p < 0.05) and loss of mitochondrial membrane potential (− 80%, p < 0.05), assessed by tetramethylrhodamine-coupled quantitative fluorescence microscopy. The mitochondria-targeted antioxidant MitoTempol prevented ROS accumulation and dissipation of mitochondrial membrane potential. Cyclosporin A, a mitochondrial permeability transition pore blocker, also abolished the mtAQP8 knockdown-induced mitochondrial depolarization. Besides, the loss of viability in mtAQP8 knockdown cells verified by MTT assay, LDH leakage, and trypan blue exclusion test could be prevented by cyclosporin A. Our data on human hepatoma HepG2 cells suggest that mtAQP8 facilitates mitochondrial H{sub 2}O{sub 2} release and that its defective expression causes ROS-induced mitochondrial depolarization via the mitochondrial permeability transition mechanism, and cell death. -- Highlights: ► Aquaporin-8 is expressed in mitochondria of human hepatoma HepG2 cells. ► Aquaporin-8 knockdown impairs mitochondrial H{sub 2}O{sub 2} release and increases ROS. ► Aquaporin

  11. Stress and coping of parents caring for a child with mitochondrial disease.

    Science.gov (United States)

    Senger, Brenda A; Ward, Linda D; Barbosa-Leiker, Celestina; Bindler, Ruth C

    2016-02-01

    Mitochondrial disease comprises a group of rare, genetic, life-limiting, neurodegenerative disorders known to affect children. Little is known about disease-related challenges, parental stress, and coping when caring for a child with a mitochondrial disease. This study explored disease-related characteristics and parental stressors and coping behaviors related to caring for a child with mitochondrial disease. Internet surveys were posted on known mitochondrial disease websites for parent completion. Surveys included demographic items and two questionnaires: Coping Inventory for Parents (CHIP) and Pediatric Inventory for Parents (PIP). Descriptive data were collected and correlations used to determine relationships between parenting stress, coping, and demographic variables. The majority of participants (n=231) were mothers (95%) of children with mitochondrial disease around the age of 10 years (M=9.85). On average, children had 6 organs involved (M=6.02) and saw 7 different specialists (M=7.49); 61% were hospitalized in the past year. Significant correlations (pstress and parent age, parent income, parent education, child age, child age at diagnosis, presence of developmental delays, number of hospitalizations, number of medical visits, number of organs involved, and number of specialists seen. Significant correlations were also found between parenting stress and coping behaviors such as family integration, social support and understanding health care. The ability to identify disease-related challenges, stressors, and coping strategies in parents of children with mitochondrial disease is novel and can assist nurses to provide disease-sensitive, family-focused care and improve child health outcomes. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. The reference human nuclear mitochondrial sequences compilation validated and implemented on the UCSC genome browser

    Directory of Open Access Journals (Sweden)

    Gasparre Giuseppe

    2011-10-01

    Full Text Available Abstract Background Eukaryotic nuclear genomes contain fragments of mitochondrial DNA called NumtS (Nuclear mitochondrial Sequences, whose mode and time of insertion, as well as their functional/structural role within the genome are debated issues. Insertion sites match with chromosomal breaks, revealing that micro-deletions usually occurring at non-homologous end joining loci become reduced in presence of NumtS. Some NumtS are involved in recombination events leading to fragment duplication. Moreover, NumtS are polymorphic, a feature that renders them candidates as population markers. Finally, they are a cause of contamination during human mtDNA sequencing, leading to the generation of false heteroplasmies. Results Here we present RHNumtS.2, the most exhaustive human NumtSome catalogue annotating 585 NumtS, 97% of which were here validated in a European individual and in HapMap samples. The NumtS complete dataset and related features have been made available at the UCSC Genome Browser. The produced sequences have been submitted to INSDC databases. The implementation of the RHNumtS.2 tracks within the UCSC Genome Browser has been carried out with the aim to facilitate browsing of the NumtS tracks to be exploited in a wide range of research applications. Conclusions We aimed at providing the scientific community with the most exhaustive overview on the human NumtSome, a resource whose aim is to support several research applications, such as studies concerning human structural variation, diversity, and disease, as well as the detection of false heteroplasmic mtDNA variants. Upon implementation of the NumtS tracks, the application of the BLAT program on the UCSC Genome Browser has now become an additional tool to check for heteroplasmic artefacts, supported by data available through the NumtS tracks.

  13. POSSIBLE ROLE OF MITOCHONDRIAL GENOME MUTATIONS IN CORONARY HEART DISEASE

    Directory of Open Access Journals (Sweden)

    L. A. Egorova

    2014-07-01

    Full Text Available Mitochondria are not only the major producers of adenosine triphosphate, but also an endogenous source of reactive oxygen species. Mitochondrialdysfunction plays a key role in the trigger and progression of atherosclerotic lesion. Impaired function in the mitochondria due to their elevated level of oxidized oxygen species, the accumulation of mitochondrial DNA damages, and the exhaustion of respiratory chains induces dysfunction and apoptosis in the endothelial cells; activation of matrix metalloproteinases; growth of vascular smooth muscle cells and their migration into the intima; expression of adhesion molecules, and oxidation of low-density lipoproteins. Mitochondrial dysfunction may be an important unifying mechanism that accounts for the atherogenic effect of major cardiovascular risk factors. Small clinical pilot studies have shown an association of different mitochondrial genome mutations with atherosclerotic lesion in the artery. Taking into account the available data on the possible role of mitochondria in atherogenesis, novel drugs are now being designed to affect mitochondrial function.

  14. Mitochondrial fatty acid oxidation alterations in heart failure, ischaemic heart disease and diabetic cardiomyopathy

    Science.gov (United States)

    Fillmore, N; Mori, J; Lopaschuk, G D

    2014-01-01

    Heart disease is a leading cause of death worldwide. In many forms of heart disease, including heart failure, ischaemic heart disease and diabetic cardiomyopathies, changes in cardiac mitochondrial energy metabolism contribute to contractile dysfunction and to a decrease in cardiac efficiency. Specific metabolic changes include a relative increase in cardiac fatty acid oxidation rates and an uncoupling of glycolysis from glucose oxidation. In heart failure, overall mitochondrial oxidative metabolism can be impaired while, in ischaemic heart disease, energy production is impaired due to a limitation of oxygen supply. In both of these conditions, residual mitochondrial fatty acid oxidation dominates over mitochondrial glucose oxidation. In diabetes, the ratio of cardiac fatty acid oxidation to glucose oxidation also increases, although primarily due to an increase in fatty acid oxidation and an inhibition of glucose oxidation. Recent evidence suggests that therapeutically regulating cardiac energy metabolism by reducing fatty acid oxidation and/or increasing glucose oxidation can improve cardiac function of the ischaemic heart, the failing heart and in diabetic cardiomyopathies. In this article, we review the cardiac mitochondrial energy metabolic changes that occur in these forms of heart disease, what role alterations in mitochondrial fatty acid oxidation have in contributing to cardiac dysfunction and the potential for targeting fatty acid oxidation to treat these forms of heart disease. LINKED ARTICLES This article is part of a themed issue on Mitochondrial Pharmacology: Energy, Injury & Beyond. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2014.171.issue-8 PMID:24147975

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

    Science.gov (United States)

    Rooijers, Koos; Loayza-Puch, Fabricio; Nijtmans, Leo G.; Agami, Reuven

    2013-12-01

    Mitochondria 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 mutations often affect components of the mitochondrial translation machinery. Here we perform ribosome profiling to measure mitochondrial translation at nucleotide resolution. Using a protocol optimized for the retrieval of mitochondrial ribosome protected fragments (RPFs) we show that the size distribution of wild-type mitochondrial RPFs follows a bimodal distribution peaking at 27 and 33 nucleotides, which is distinct from the 30-nucleotide peak of nuclear RPFs. Their cross-correlation suggests generation of mitochondrial RPFs during ribosome progression. In contrast, RPFs from patient-derived mitochondria mutated in tRNA-Tryptophan are centered on tryptophan codons and reduced downstream, indicating ribosome stalling. Intriguingly, long RPFs are enriched in mutated mitochondria, suggesting they characterize stalled ribosomes. Our findings provide the first model for translation in wild-type and disease-triggering mitochondria.

  16. Cyclophilin D deficiency attenuates mitochondrial and neuronal perturbation and ameliorates learning and memory in Alzheimer's disease.

    Science.gov (United States)

    Du, Heng; Guo, Lan; Fang, Fang; Chen, Doris; Sosunov, Alexander A; McKhann, Guy M; Yan, Yilin; Wang, Chunyu; Zhang, Hong; Molkentin, Jeffery D; Gunn-Moore, Frank J; Vonsattel, Jean Paul; Arancio, Ottavio; Chen, John Xi; Yan, Shi Du

    2008-10-01

    Cyclophilin D (CypD, encoded by Ppif) is an integral part of the mitochondrial permeability transition pore, whose opening leads to cell death. Here we show that interaction of CypD with mitochondrial amyloid-beta protein (Abeta) potentiates mitochondrial, neuronal and synaptic stress. The CypD-deficient cortical mitochondria are resistant to Abeta- and Ca(2+)-induced mitochondrial swelling and permeability transition. Additionally, they have an increased calcium buffering capacity and generate fewer mitochondrial reactive oxygen species. Furthermore, the absence of CypD protects neurons from Abeta- and oxidative stress-induced cell death. Notably, CypD deficiency substantially improves learning and memory and synaptic function in an Alzheimer's disease mouse model and alleviates Abeta-mediated reduction of long-term potentiation. Thus, the CypD-mediated mitochondrial permeability transition pore is directly linked to the cellular and synaptic perturbations observed in the pathogenesis of Alzheimer's disease. Blockade of CypD may be a therapeutic strategy in Alzheimer's disease.

  17. Distinct patterns of mitochondrial genome diversity in bonobos (Pan paniscus and humans

    Directory of Open Access Journals (Sweden)

    Zsurka Gábor

    2010-09-01

    Full Text Available Abstract Background We have analyzed the complete mitochondrial genomes of 22 Pan paniscus (bonobo, pygmy chimpanzee individuals to assess the detailed mitochondrial DNA (mtDNA phylogeny of this close relative of Homo sapiens. Results We identified three major clades among bonobos that separated approximately 540,000 years ago, as suggested by Bayesian analysis. Incidentally, we discovered that the current reference sequence for bonobo likely is a hybrid of the mitochondrial genomes of two distant individuals. When comparing spectra of polymorphic mtDNA sites in bonobos and humans, we observed two major differences: (i Of all 31 bonobo mtDNA homoplasies, i.e. nucleotide changes that occurred independently on separate branches of the phylogenetic tree, 13 were not homoplasic in humans. This indicates that at least a part of the unstable sites of the mitochondrial genome is species-specific and difficult to be explained on the basis of a mutational hotspot concept. (ii A comparison of the ratios of non-synonymous to synonymous changes (dN/dS among polymorphic positions in bonobos and in 4902 Homo sapiens mitochondrial genomes revealed a remarkable difference in the strength of purifying selection in the mitochondrial genes of the F0F1-ATPase complex. While in bonobos this complex showed a similar low value as complexes I and IV, human haplogroups displayed 2.2 to 7.6 times increased dN/dS ratios when compared to bonobos. Conclusions Some variants of mitochondrially encoded subunits of the ATPase complex in humans very likely decrease the efficiency of energy conversion leading to production of extra heat. Thus, we hypothesize that the species-specific release of evolutionary constraints for the mitochondrial genes of the proton-translocating ATPase is a consequence of altered heat homeostasis in modern humans.

  18. Distinct patterns of mitochondrial genome diversity in bonobos (Pan paniscus) and humans.

    Science.gov (United States)

    Zsurka, Gábor; Kudina, Tatiana; Peeva, Viktoriya; Hallmann, Kerstin; Elger, Christian E; Khrapko, Konstantin; Kunz, Wolfram S

    2010-09-02

    We have analyzed the complete mitochondrial genomes of 22 Pan paniscus (bonobo, pygmy chimpanzee) individuals to assess the detailed mitochondrial DNA (mtDNA) phylogeny of this close relative of Homo sapiens. We identified three major clades among bonobos that separated approximately 540,000 years ago, as suggested by Bayesian analysis. Incidentally, we discovered that the current reference sequence for bonobo likely is a hybrid of the mitochondrial genomes of two distant individuals. When comparing spectra of polymorphic mtDNA sites in bonobos and humans, we observed two major differences: (i) Of all 31 bonobo mtDNA homoplasies, i.e. nucleotide changes that occurred independently on separate branches of the phylogenetic tree, 13 were not homoplasic in humans. This indicates that at least a part of the unstable sites of the mitochondrial genome is species-specific and difficult to be explained on the basis of a mutational hotspot concept. (ii) A comparison of the ratios of non-synonymous to synonymous changes (dN/dS) among polymorphic positions in bonobos and in 4902 Homo sapiens mitochondrial genomes revealed a remarkable difference in the strength of purifying selection in the mitochondrial genes of the F0F1-ATPase complex. While in bonobos this complex showed a similar low value as complexes I and IV, human haplogroups displayed 2.2 to 7.6 times increased dN/dS ratios when compared to bonobos. Some variants of mitochondrially encoded subunits of the ATPase complex in humans very likely decrease the efficiency of energy conversion leading to production of extra heat. Thus, we hypothesize that the species-specific release of evolutionary constraints for the mitochondrial genes of the proton-translocating ATPase is a consequence of altered heat homeostasis in modern humans.

  19. 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

    Using the human Müller cell line, MIO-M1, the aim was to study the impact of mitochondrial inhibition in Müller glia through antimycin A treatment. MIO-M1 cell survival, levels of released lactate, mitochondrial function, and glutamate uptake were studied in response to mitochondrial inhibition a...

  20. Mitochondrial and Ubiquitin Proteasome System Dysfunction in Ageing and Disease: Two Sides of the Same Coin?

    Directory of Open Access Journals (Sweden)

    Jaime M. Ross

    2015-08-01

    Full Text Available Mitochondrial dysfunction and impairment of the ubiquitin proteasome system have been described as two hallmarks of the ageing process. Additionally, both systems have been implicated in the etiopathogenesis of many age-related diseases, particularly neurodegenerative disorders, such as Alzheimer’s and Parkinson’s disease. Interestingly, these two systems are closely interconnected, with the ubiquitin proteasome system maintaining mitochondrial homeostasis by regulating organelle dynamics, the proteome, and mitophagy, and mitochondrial dysfunction impairing cellular protein homeostasis by oxidative damage. Here, we review the current literature and argue that the interplay of the two systems should be considered in order to better understand the cellular dysfunction observed in ageing and age-related diseases. Such an approach may provide valuable insights into molecular mechanisms underlying the ageing process, and further discovery of treatments to counteract ageing and its associated diseases. Furthermore, we provide a hypothetical model for the heterogeneity described among individuals during ageing.

  1. Possible role of mitochondrial permeability transition pore in the pathogenesis of Huntington disease.

    Science.gov (United States)

    Quintanilla, Rodrigo A; Tapia, Cheril; Pérez, María José

    2017-02-19

    Huntington disease (HD) is a devastating neurological disorder that affects the striatum and cortex of patients. HD patients develop progressive motor dysfunction and psychiatric disturbances with gradual dementia. HD is caused by a pathological expansion of CAG repeats in the huntingtin gene that codifies for a protein called huntingtin (Htt), which principal function is not completely understood. Accumulative evidence shows that this pathological expansion modifies Htt function affecting different neuronal targets, including mitochondrial function which is an important factor that contributes to HD. Interestingly, several groups have shown mitochondrial disturbances including calcium handling defects, depolarization, decrease of mitochondrial transport, ATP reduction, and increase of reactive oxygen species (ROS) in cellular and murine HD models. Systematic analysis of this evidence indicates that a mitochondrial structure, the mitochondrial permeability transition pore (mPTP), could be responsible for these changes that affect mitochondria. The mPTP plays an important role in apoptosis and neurodegeneration. It has also been reported to have some physiological functions in heart development and synaptic communication. In HD, the presence of mutant huntingtin (mHtt) activates this mechanism producing a significant compromise of mitochondrial metabolism and bioenergetics. Considering these findings this review explores the evidence that suggests the important role of mPTP in the mitochondrial impairment induced by mHtt, which leads to calcium derangement and contributes to neuronal dysfunction in HD. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Mitochondrial mislocalization underlies Abeta42-induced neuronal dysfunction in a Drosophila model of Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Kanae Iijima-Ando

    2009-12-01

    Full Text Available The amyloid-beta 42 (Abeta42 is thought to play a central role in the pathogenesis of Alzheimer's disease (AD. However, the molecular mechanisms by which Abeta42 induces neuronal dysfunction and degeneration remain elusive. Mitochondrial dysfunctions are implicated in AD brains. Whether mitochondrial dysfunctions are merely a consequence of AD pathology, or are early seminal events in AD pathogenesis remains to be determined. Here, we show that Abeta42 induces mitochondrial mislocalization, which contributes to Abeta42-induced neuronal dysfunction in a transgenic Drosophila model. In the Abeta42 fly brain, mitochondria were reduced in axons and dendrites, and accumulated in the somata without severe mitochondrial damage or neurodegeneration. In contrast, organization of microtubule or global axonal transport was not significantly altered at this stage. Abeta42-induced behavioral defects were exacerbated by genetic reductions in mitochondrial transport, and were modulated by cAMP levels and PKA activity. Levels of putative PKA substrate phosphoproteins were reduced in the Abeta42 fly brains. Importantly, perturbations in mitochondrial transport in neurons were sufficient to disrupt PKA signaling and induce late-onset behavioral deficits, suggesting a mechanism whereby mitochondrial mislocalization contributes to Abeta42-induced neuronal dysfunction. These results demonstrate that mislocalization of mitochondria underlies the pathogenic effects of Abeta42 in vivo.

  3. Mitochondrial lysates induce inflammation and Alzheimer's disease-relevant changes in microglial and neuronal cells.

    Science.gov (United States)

    Wilkins, Heather M; Carl, Steven M; Weber, Sam G; Ramanujan, Suruchi A; Festoff, Barry W; Linseman, Daniel A; Swerdlow, Russell H

    2015-01-01

    Neuroinflammation occurs in Alzheimer's disease (AD). While AD genetic studies implicate inflammation-relevant genes and fibrillar amyloid-β protein promotes inflammation, our understanding of AD neuroinflammation nevertheless remains incomplete. In this study we hypothesized damage-associated molecular pattern (DAMP) molecules arising from mitochondria, intracellular organelles that resemble bacteria, could contribute to AD neuroinflammation. To preliminarily test this possibility, we exposed neuronal and microglial cell lines to enriched mitochondrial lysates. BV2 microglial cells treated with mitochondrial lysates showed decreased TREM2 mRNA, increased TNFα mRNA, increased MMP-8 mRNA, increased IL-8 mRNA, redistribution of NFκB to the nucleus, and increased p38 MAPK phosphorylation. SH-SY5Y neuronal cells treated with mitochondrial lysates showed increased TNFα mRNA, increased NFκB protein, decreased IκBα protein, increased AβPP mRNA, and increased AβPP protein. Enriched mitochondrial lysates from SH-SY5Y cells lacking detectable mitochondrial DNA (ρ0 cells) failed to induce any of these changes, while mtDNA obtained directly from mitochondria (but not PCR-amplified mtDNA) increased BV2 cell TNFα mRNA. These results indicate at least one mitochondrial-derived DAMP molecule, mtDNA, can induce inflammatory changes in microglial and neuronal cell lines. Our data are consistent with the hypothesis that a mitochondrial-derived DAMP molecule or molecules could contribute to AD neuroinflammation.

  4. Ophiobolin A Induces Autophagy and Activates the Mitochondrial Pathway of Apoptosis in Human Melanoma Cells.

    Directory of Open Access Journals (Sweden)

    Carlo Rodolfo

    Full Text Available Ophiobolin A, a fungal toxin from Bipolaris species known to affect different cellular processes in plants, has recently been shown to have anti-cancer activity in mammalian cells. In the present study, we investigated the anti-proliferative effect of Ophiobolin A on human melanoma A375 and CHL-1 cell lines. This cellular model was chosen because of the incidence of melanoma malignant tumor on human population and its resistance to chemical treatments. Ophyobolin A strongly reduced cell viability of melanoma cells by affecting mitochondrial functionality. The toxin induced depolarization of mitochondrial membrane potential, reactive oxygen species production and mitochondrial network fragmentation, leading to autophagy induction and ultimately resulting in cell death by activation of the mitochondrial pathway of apoptosis. Finally, a comparative proteomic investigation on A375 cells allowed to identify several Ophiobolin A down-regulated proteins, which are involved in fundamental processes for cell homeostasis and viability.

  5. Oxidative stress and mitochondrial impairment can be separated from lipofuscin accumulation in aged human skeletal muscle

    DEFF Research Database (Denmark)

    Hütter, Eveline; Skovbro, Mette; Lener, Barbara

    2007-01-01

    According to the free radical theory of aging, reactive oxygen species (ROS) act as a driving force of the aging process, and it is generally believed that mitochondrial dysfunction is a major source of increased oxidative stress in tissues with high content of mitochondria, such as muscle or brain...... mitochondria and that the level of ROS production is higher in young compared to aged muscle. Accordingly, we could not find any increase in oxidative modification of proteins in muscle from elderly donors. However, the accumulation of lipofuscin was identified as a robust marker of human muscle aging....... However, recent experiments in mouse models of premature aging have questioned the role of mitochondrial ROS production in premature aging. To address the role of mitochondrial impairment and ROS production for aging in human muscles, we have analyzed mitochondrial properties in muscle fibres isolated...

  6. Mitochondrial Effects of PGC-1alpha Silencing in MPP+ Treated Human SH-SY5Y Neuroblastoma Cells

    Directory of Open Access Journals (Sweden)

    Qinyong Ye

    2017-05-01

    Full Text Available The dopaminergic neuron degeneration and loss that occurs in Parkinson’s disease (PD has been tightly linked to mitochondrial dysfunction. Although the aged-related cause of the mitochondrial defect observed in PD patients remains unclear, nuclear genes are of potential importance to mitochondrial function. Human peroxisome proliferator-activated receptor γ coactivator-1alpha (PGC-1α is a multi-functional transcription factor that tightly regulates mitochondrial biogenesis and oxidative capacity. The goal of the present study was to explore the potential pathogenic effects of interference by the PGC-1α gene on N-methyl-4-phenylpyridinium ion (MPP+-induced SH-SY5Y cells. We utilized RNA interference (RNAi technology to probe the pathogenic consequences of inhibiting PGC-1α in the SH-SY5Y cell line. Remarkably, a reduction in PGC-1α resulted in the reduction of mitochondrial membrane potential, intracellular ATP content and intracellular H2O2 generation, leading to the translocation of cytochrome c (cyt c to the cytoplasm in the MPP+-induced PD cell model. The expression of related proteins in the signaling pathway (e.g., estrogen-related receptor α (ERRα, nuclear respiratory factor 1 (NRF-1, NRF-2 and Peroxisome proliferator-activated receptor γ (PPARγ also decreased. Our finding indicates that small interfering RNA (siRNA interference targeting the PGC-1α gene could inhibit the function of mitochondria in several capacities and that the PGC-1α gene may modulate mitochondrial function by regulating the expression of ERRα, NRF-1, NRF-2 and PPARγ. Thus, PGC-1α can be considered a potential therapeutic target for PD.

  7. Proteomic Profiling of Human Liver Biopsies: Hepatitis C Virus-Induced Fibrosis and Mitochondrial Dysfunction

    Energy Technology Data Exchange (ETDEWEB)

    Diamond, Deborah L.; Jacobs, Jon M.; Paeper, Bryan; Proll, Sean; Gritsenko, Marina A.; Carithers, Jr., Robert L.; Larson , Anne M.; Yeh, Matthew M.; Camp, David G.; Smith, Richard D.; Katze, Michael G.

    2007-09-01

    Liver biopsies from HCV-infected patients offer the unique opportunity to study human liver biology and disease in vivo. However, the low protein yields associated with these small samples present a significant challenge for proteomic analysis. In this study we describe the application of an ultra-sensitive proteomics platform for performing robust quantitative proteomic studies on microgram amounts of HCV-infected human liver tissue from 15 patients at different stages of fibrosis. A high quality liver protein data base containing 5,920 unique protein identifications supported high throughput quantitative studies using 16O:18O stable isotope labeling in combination with the accurate mass and time (AMT) tag approach. A total of 1,641 liver biopsy proteins were quantified and ANOVA identified 210 proteins exhibiting statistically significant differences associated with fibrosis stage. Hierarchical clustering revealed that biopsies representative of later fibrosis stages (e.g. Batts-Ludwig stages 3-4) exhibited a distinct protein expression profile indicating an apparent down-regulation of many proteins when compared to samples from earlier fibrosis stages (e.g. Batts-Ludwig stages 0-2). Functional analysis of these signature proteins suggests that impairment of key mitochondrial processes including fatty acid oxidation and oxidative phosphorylation, and response to oxidative stress and reactive oxygen species occurs during advanced stage 3-4 fibrosis. In conclusion, the results reported here represent a significant advancement in clinical proteomics providing to our knowledge, the first demonstration of global proteomic alterations accompanying liver disease progression in patients chronically infected with HCV. Our findings contribute to a generally emerging theme associating oxidative stress and hepatic mitochondrial dysfunction with HCV pathogenesis.

  8. Mitochondrial functional changes characterization in young and senescent human adipose derived MSCs

    Directory of Open Access Journals (Sweden)

    Bernd Robert Stab II

    2016-12-01

    Full Text Available Mitochondria are highly dynamic organelles that in response to the cell’s bio-energetic state continuously undergo structural remodeling fission and fusion processes. This mitochondrial dynamic activity has been implicated in cell cycle, autophagy and age-related diseases. Adult tissue-derived mesenchymal stromal/stem cells present a therapeutic potential. However, to obtain an adequate mesenchymal stromal/stem cell number for clinical use, extensive in vitro expansion is required. Unfortunately, these cells undergo replicative senescence rapidly by mechanisms that are not well understood. Senescence has been associated with metabolic changes in the oxidative state of the cell, a process that has been also linked to mitochondrial fission and fusion events, suggesting an association between mitochondrial dynamic and senescence. In the present work, we studied the mitochondrial structural remodeling process of mesenchymal stromal/stem cells isolated from adipose tissue in vitro to determine if mitochondrial phenotypic changes are associated with mesenchymal stromal/stem cell senescence. For this purpose, mitochondrial dynamics and oxidative state of stromal/stem cell were compared between young and old cells. With increased cell passage, we observed a significant change in cell morphology that is associated with an increase in β-galactosidase activity. In addition, old cells (population doubling seven also showed increased mitochondrial mass, augmented superoxide production, and decreased mitochondrial membrane potential. These changes in morphology were related to slightly levels increases in mitochondrial fusion proteins, Mitofusion 1 (MFN1 and Dynamin-realted GTPase (OPA1. Collectively, our results showed that adipose tissue-derived MSCs at population doubling seven develop a senescent phenotype that is characterized by metabolic cell changes that can lead to mitochondrial fusion.

  9. Recurrent De Novo Dominant Mutations in SLC25A4 Cause Severe Early-Onset Mitochondrial Disease and Loss of Mitochondrial DNA Copy Number.

    Science.gov (United States)

    Thompson, Kyle; Majd, Homa; Dallabona, Cristina; Reinson, Karit; King, Martin S; Alston, Charlotte L; He, Langping; Lodi, Tiziana; Jones, Simon A; Fattal-Valevski, Aviva; Fraenkel, Nitay D; Saada, Ann; Haham, Alon; Isohanni, Pirjo; Vara, Roshni; Barbosa, Inês A; Simpson, Michael A; Deshpande, Charu; Puusepp, Sanna; Bonnen, Penelope E; Rodenburg, Richard J; Suomalainen, Anu; Õunap, Katrin; Elpeleg, Orly; Ferrero, Ileana; McFarland, Robert; Kunji, Edmund R S; Taylor, Robert W

    2016-10-06

    Mutations in SLC25A4 encoding the mitochondrial ADP/ATP carrier AAC1 are well-recognized causes of mitochondrial disease. Several heterozygous SLC25A4 mutations cause adult-onset autosomal-dominant progressive external ophthalmoplegia associated with multiple mitochondrial DNA deletions, whereas recessive SLC25A4 mutations cause childhood-onset mitochondrial myopathy and cardiomyopathy. Here, we describe the identification by whole-exome sequencing of seven probands harboring dominant, de novo SLC25A4 mutations. All affected individuals presented at birth, were ventilator dependent and, where tested, revealed severe combined mitochondrial respiratory chain deficiencies associated with a marked loss of mitochondrial DNA copy number in skeletal muscle. Strikingly, an identical c.239G>A (p.Arg80His) mutation was present in four of the seven subjects, and the other three case subjects harbored the same c.703C>G (p.Arg235Gly) mutation. Analysis of skeletal muscle revealed a marked decrease of AAC1 protein levels and loss of respiratory chain complexes containing mitochondrial DNA-encoded subunits. We show that both recombinant AAC1 mutant proteins are severely impaired in ADP/ATP transport, affecting most likely the substrate binding and mechanics of the carrier, respectively. This highly reduced capacity for transport probably affects mitochondrial DNA maintenance and in turn respiration, causing a severe energy crisis. The confirmation of the pathogenicity of these de novo SLC25A4 mutations highlights a third distinct clinical phenotype associated with mutation of this gene and demonstrates that early-onset mitochondrial disease can be caused by recurrent de novo mutations, which has significant implications for the application and analysis of whole-exome sequencing data in mitochondrial disease. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  10. A novel MTTT mutation m.15933G > A revealed in analysis of mitochondrial DNA in patients with suspected mitochondrial disease.

    Science.gov (United States)

    Soini, Heidi K; Väisänen, Antti; Kärppä, Mikko; Hinttala, Reetta; Kytövuori, Laura; Moilanen, Jukka S; Uusimaa, Johanna; Majamaa, Kari

    2017-02-10

    Mitochondrial diseases present with variable multi-organ symptoms. Common disease-causing mutations in mitochondrial DNA (mtDNA) are regularly screened in diagnostic work-up, but novel mutations may remain unnoticed. Patients (N = 66) with a clinical suspicion of mitochondrial disease were screened for their mtDNA coding region using conformation sensitive gel electrophoresis and sequencing. Long-PCR was used to detect deletions followed by POLG1 sequencing in patients with multiple deletions. We discovered three novel mtDNA variants that included m.8743G > C, m.11322A > G and m.15933G > A. The novel MTTT variant m.15933G > A is suggested to be pathogenic. Analysis revealed also multiple mtDNA deletions in two patients and five nonsynonymous variants that were putatively pathogenic according to in-silico prediction algorithms. In addition, a rare haplogroup H associated m.7585_7586insT variant was discovered. Among patients with a suspected mitochondrial disease, a novel MTTT variant m.15933G > A was discovered and is suggested to be pathogenic. In addition, several putatively pathogenic nonsynonymous variants and rare variants were found. These findings highlight the importance of coding region mtDNA screening among patients with clinical features suggesting a mitochondrial disease, but who lack the common mitochondrial disease mutations.

  11. Mitochondrial Disease: mtDNA and Protein Segregation Mysteries in iPSCs

    OpenAIRE

    Pickrell, Alicia M.; Youle, Richard J.

    2013-01-01

    Mitochondrial diseases cause a range of clinical manifestations even in patients carrying the same mtDNA mutations. New work reveals that a common disease-associated mtDNA mutation is selectively segregated from wild-type mtDNA during the reprogramming of induced pluripotent stem cells and that high levels of this mutation in differentiated neurons upregulate Parkin-mediated mitophagy.

  12. Mitochondrial disease in autism spectrum disorder patients: a cohort analysis.

    Directory of Open Access Journals (Sweden)

    Jacqueline R Weissman

    Full Text Available Previous reports indicate an association between autism spectrum disorders (ASD and disorders of mitochondrial oxidative phosphorylation. One study suggested that children with both diagnoses are clinically indistinguishable from children with idiopathic autism. There are, however, no detailed analyses of the clinical and laboratory findings in a large cohort of these children. Therefore, we undertook a comprehensive review of patients with ASD and a mitochondrial disorder.We reviewed medical records of 25 patients with a primary diagnosis of ASD by DSM-IV-TR criteria, later determined to have enzyme- or mutation-defined mitochondrial electron transport chain (ETC dysfunction. Twenty-four of 25 patients had one or more major clinical abnormalities uncommon in idiopathic autism. Twenty-one patients had histories of significant non-neurological medical problems. Nineteen patients exhibited constitutional symptoms, especially excessive fatigability. Fifteen patients had abnormal neurological findings. Unusual developmental phenotypes included marked delay in early gross motor milestones (32% and unusual patterns of regression (40%. Levels of blood lactate, plasma alanine, and serum ALT and/or AST were increased at least once in 76%, 36%, and 52% of patients, respectively. The most common ETC disorders were deficiencies of complex I (64% and complex III (20%. Two patients had rare mtDNA mutations of likely pathogenicity.Although all patients' initial diagnosis was idiopathic autism, careful clinical and biochemical assessment identified clinical findings that differentiated them from children with idiopathic autism. These and prior data suggest a disturbance of mitochondrial energy production as an underlying pathophysiological mechanism in a subset of individuals with autism.

  13. αSynuclein and Mitochondrial Dysfunction: A Pathogenic Partnership in Parkinson’s Disease?

    Directory of Open Access Journals (Sweden)

    David Protter

    2012-01-01

    Full Text Available Parkinson’s Disease (PD is a complex, chronic, progressive, and debilitating neurodegenerative disorder. Neither a cure nor effective long-term therapy exist and the lack of knowledge of the molecular mechanisms responsible for PD development is a major impediment to therapeutic advances. The protein αSynuclein is a central component in PD pathogenesis yet its cellular targets and mechanism of toxicity remains unknown. Mitochondrial dysfunction is also a common theme in PD patients and this review explores the strong possibility that αSynuclein and mitochondrial dysfunction have an inter-relationship responsible for underlying the disease pathology. Amplifying cycles of mitochondrial dysfunction and αSynuclein toxicity can be envisaged, with either being the disease-initiating factor yet acting together during disease progression. Multiple potential mechanisms exist in which mitochondrial dysfunction and αSynuclein could interact to exacerbate their neurodegenerative properties. Candidates discussed within this review include autophagy, mitophagy, mitochondrial dynamics/fusion/fission, oxidative stress and reactive oxygen species, endoplasmic reticulum stress, calcium, nitrosative stress and αSynuclein Oligomerization.

  14. A review of the mitochondrial and glycolytic metabolism in human platelets and leukocytes: Implications for their use as bioenergetic biomarkers

    Directory of Open Access Journals (Sweden)

    Philip A. Kramer

    2014-01-01

    Full Text Available The assessment of metabolic function in cells isolated from human blood for treatment and diagnosis of disease is a new and important area of translational research. It is now becoming clear that a broad range of pathologies which present clinically with symptoms predominantly in one organ, such as the brain or kidney, also modulate mitochondrial energetics in platelets and leukocytes allowing these cells to serve as “the canary in the coal mine” for bioenergetic dysfunction. This opens up the possibility that circulating platelets and leukocytes can sense metabolic stress in patients and serve as biomarkers of mitochondrial dysfunction in human pathologies such as diabetes, neurodegeneration and cardiovascular disease. In this overview we will describe how the utilization of glycolysis and oxidative phosphorylation differs in platelets and leukocytes and discuss how they can be used in patient populations. Since it is clear that the metabolic programs between leukocytes and platelets are fundamentally distinct the measurement of mitochondrial function in distinct cell populations is necessary for translational research.

  15. A review of the mitochondrial and glycolytic metabolism in human platelets and leukocytes: implications for their use as bioenergetic biomarkers.

    Science.gov (United States)

    Kramer, Philip A; Ravi, Saranya; Chacko, Balu; Johnson, Michelle S; Darley-Usmar, Victor M

    2014-01-01

    The assessment of metabolic function in cells isolated from human blood for treatment and diagnosis of disease is a new and important area of translational research. It is now becoming clear that a broad range of pathologies which present clinically with symptoms predominantly in one organ, such as the brain or kidney, also modulate mitochondrial energetics in platelets and leukocytes allowing these cells to serve as "the canary in the coal mine" for bioenergetic dysfunction. This opens up the possibility that circulating platelets and leukocytes can sense metabolic stress in patients and serve as biomarkers of mitochondrial dysfunction in human pathologies such as diabetes, neurodegeneration and cardiovascular disease. In this overview we will describe how the utilization of glycolysis and oxidative phosphorylation differs in platelets and leukocytes and discuss how they can be used in patient populations. Since it is clear that the metabolic programs between leukocytes and platelets are fundamentally distinct the measurement of mitochondrial function in distinct cell populations is necessary for translational research.

  16. Acute mitochondrial and chronic toxicological effects of 1-methyl-4-phenylpyridinium in human neuroblastoma cells.

    Science.gov (United States)

    Stephans, Stacy E; Miller, Gary W; Levey, Allan I; Greenamyre, J Timothy

    2002-10-01

    At low micromolar concentrations, 1-methyl-4-phenylpyridinium (MPP+), the toxic metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) selectively kills nigrostriatal dopaminergic neurons by mechanisms believed to involve impairment of mitochondrial complex I. A human neuroblastoma cell line expressing the dopamine transporter (DAT) was utilized to examine the effects of MPP+ on acute physiologic responses and subsequent cell death. Acute responses were measured by microphysiometry and by monitoring mitochondrial membrane potential with [3H]tetraphenylphosphonium (TPP+) uptake. MPP+ (10 microM) increased extracellular proton excretion in DAT-expressing cells within 2-3 min, but had no effect in untransfected cells. The lipophilic complex I inhibitor, rotenone, increased proton excretion in both cell lines. In DAT-expressing cells, mitochondrial membrane potential was reduced within I h of 10 microM MPP+ exposure. Rotenone reduced mitochondrial membrane potential in both cell lines. MPP+ caused apoptotic death of DAT-transfected cells 2-3 days after drug application, but did not kill untransfected cells. Thus, MPP+ produces immediate mitochondrial impairment only in cells that express DAT, and these changes occur days before overt cellular toxicity. The magnitude, time course and nature of these changes were similar to those produced by rotenone, confirming the site of action of MPP+ as mitochondrial complex I. These immediate mitochondrial effects appear to be an accurate predictor of subsequent cell death.

  17. Synchronism in mitochondrial ROS flashes, membrane depolarization and calcium sparks in human carcinoma cells.

    Science.gov (United States)

    Kuznetsov, Andrey V; Javadov, Sabzali; Saks, Valdur; Margreiter, Raimund; Grimm, Michael

    2017-06-01

    Mitochondria are major producers of reactive oxygen species (ROS) in many cells including cancer cells. However, complex interrelationships between mitochondrial ROS (mitoROS), mitochondrial membrane potential (ΔΨm) and Ca2+ are not completely understood. Using human carcinoma cells, we further highlight biphasic ROS dynamics: - gradual mitoROS increase followed by mitoROS flash. Also, we demonstrate heterogeneity in rates of mitoROS generation and flash initiation time. Comparing mitochondrial and near-extra-mitochondrial signals, we show that mechanisms of mitoROS flashes in single mitochondria, linked to mitochondrial permeability transition pore opening (ΔΨm collapse) and calcium sparks, may involve flash triggering by certain levels of external ROS released from the same mitochondria. In addition, mitochondria-mitochondria interactions can produce wave propagations of mitoROS flashes and ΔΨm collapses in cancer cells similar to phenomena of ROS-induced ROS release (RIRR). Our data suggest that in cancer cells RIRR, activation of mitoROS flashes and mitochondrial depolarization may involve participation of extramitochondrial-ROS produced either by individual mitochondria and/or by neighboring mitochondria. This could represent general mechanisms in ROS-ROS signaling with suggested role in both mitochondrial and cellular physiology and signaling. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. FDXR Mutations Cause Sensorial Neuropathies and Expand the Spectrum of Mitochondrial Fe-S-Synthesis Diseases.

    Science.gov (United States)

    Paul, Antoine; Drecourt, Anthony; Petit, Floriane; Deguine, Delphine Dupin; Vasnier, Christelle; Oufadem, Myriam; Masson, Cécile; Bonnet, Crystel; Masmoudi, Saber; Mosnier, Isabelle; Mahieu, Laurence; Bouccara, Didier; Kaplan, Josseline; Challe, Georges; Domange, Christelle; Mochel, Fanny; Sterkers, Olivier; Gerber, Sylvie; Nitschke, Patrick; Bole-Feysot, Christine; Jonard, Laurence; Gherbi, Souad; Mercati, Oriane; Ben Aissa, Ines; Lyonnet, Stanislas; Rötig, Agnès; Delahodde, Agnès; Marlin, Sandrine

    2017-10-05

    Hearing loss and visual impairment in childhood have mostly genetic origins, some of them being related to sensorial neuronal defects. Here, we report on eight subjects from four independent families affected by auditory neuropathy and optic atrophy. Whole-exome sequencing revealed biallelic mutations in FDXR in affected subjects of each family. FDXR encodes the mitochondrial ferredoxin reductase, the sole human ferredoxin reductase implicated in the biosynthesis of iron-sulfur clusters (ISCs) and in heme formation. ISC proteins are involved in enzymatic catalysis, gene expression, and DNA replication and repair. We observed deregulated iron homeostasis in FDXR mutant fibroblasts and indirect evidence of mitochondrial iron overload. Functional complementation in a yeast strain in which ARH1, the human FDXR ortholog, was deleted established the pathogenicity of these mutations. These data highlight the wide clinical heterogeneity of mitochondrial disorders related to ISC synthesis. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  19. Multiparameter metabolic analysis reveals a close link between attenuated mitochondrial bioenergetic function and enhanced glycolysis dependency in human tumor cells

    National Research Council Canada - National Science Library

    Min Wu; Andy Neilson; Amy L. Swift; Rebecca Moran; James Tamagnine; Diane Parslow; Suzanne Armistead; Kristie Lemire; Jim Orrell; Jay Teich; Steve Chomicz; David A. Ferrick

    .... Using a novel approach to measure cellular metabolic rates in vitro, the bioenergetic basis of this increased glycolysis and reduced mitochondrial respiration was investigated in two human cancer...

  20. Mitochondrial genome analyses suggest multiple Trichuris species in humans, baboons, and pigs from different geographical regions

    DEFF Research Database (Denmark)

    Hawash, Mohamed B. F.; Andersen, Lee O.; Gasser, Robin B.

    2015-01-01

    in primates. METHODS AND FINDINGS: We sequenced and annotated complete mitochondrial genomes of Trichuris recovered from a human in Uganda, an olive baboon in the US, a hamadryas baboon in Denmark, and two pigs from Denmark and Uganda. Comparative analyses using other published mitochondrial genomes......) suggesting that they represented different species. Trichuris from the olive baboon in US was genetically related to human Trichuris in China, while the other from the hamadryas baboon in Denmark was nearly identical to human Trichuris from Uganda. Baboon-derived Trichuris was genetically distinct from...

  1. Direct effects of mitochondrial dysfunction on poor bone health in Leigh syndrome.

    Science.gov (United States)

    Kato, Hiroki; Han, Xu; Yamaza, Haruyoshi; Masuda, Keiji; Hirofuji, Yuta; Sato, Hiroshi; Pham, Thanh Thi Mai; Taguchi, Tomoaki; Nonaka, Kazuaki

    2017-11-04

    Mitochondrial diseases are the result of aberrant mitochondrial function caused by mutations in either nuclear or mitochondrial DNA. Poor bone health has recently been suggested as a symptom of mitochondrial diseases; however, a direct link between decreased mitochondrial function and poor bone health in mitochondrial disease has not been demonstrated. In this study, stem cells from human exfoliated deciduous teeth (SHED) were isolated from a child with Leigh syndrome (LS), a mitochondrial disease, and the effects of decreased mitochondrial function on poor bone health were analyzed. Compared with control SHED, LS SHED displayed decreased osteoblastic differentiation and calcium mineralization. The intracellular and mitochondrial calcium levels were lower in LS SHED than in control SHED. Furthermore, the mitochondrial activity of LS SHED was decreased compared with control SHED both with and without osteoblastic differentiation. Our results indicate that decreased osteoblast differentiation potential and osteoblast function contribute to poor bone health in mitochondrial diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Could we offer mitochondrial donation or similar assisted reproductive technology to South African patients with mitochondrial DNA disease?

    Science.gov (United States)

    Meldau, Surita; Riordan, Gillian; Van der Westhuizen, Francois; Elson, Joanna L; Smuts, Izelle; Pepper, Michael S; Soodyall, Himla

    2016-02-02

    The decision of the UK House of Commons in 2015 to endorse the use of pioneering in vitro fertilisation techniques to protect future generations from the risk of mitochondrial DNA (mtDNA) disease has sparked worldwide controversy and debate. The availability of such technologies could benefit women at risk of transmitting deleterious mutations. MtDNA disease certainly occurs in South Africa (SA) in all population groups. However, diagnostic strategies and practices for identifying individuals who would benefit from technologies such as IVF have in the past been suboptimal in this country. New developments in the molecular diagnostic services available to SA patients, as well as better education of referring clinicians and the implementation of more structured, population-appropriate diagnostic strategies, may open the floor to this debate in SA.

  3. The role of mitochondrial disturbances in Alzheimer, Parkinson and Huntington diseases.

    Science.gov (United States)

    Carvalho, Cristina; Correia, Sónia C; Cardoso, Susana; Plácido, Ana I; Candeias, Emanuel; Duarte, Ana I; Moreira, Paula I

    2015-01-01

    Mitochondria are highly dynamic organelles involved in a multitude of cellular events. Disturbances of mitochondrial function and dynamics are associated with cells degeneration and death. Neurons, perhaps more than any other cell, depend on mitochondria for their survival. In fact, accumulating evidence reveals that mitochondria take center stage in several neurodegenerative diseases. Here we will give an overview of the mechanisms involved in the maintenance of a healthy mitochondrial pool in neuronal cells and how disturbances in these processes underlie the pathophysiology of three common neurodegenerative disorders, Alzheimer, Parkinson and Huntington diseases. Additionally, we will discuss the role of sirtuins in neurodegeneration and how mitohormesis and vitagenes activation may counteract neurodegenerative events.

  4. Increased mitochondrial apoptotic priming of human regulatory T cells after allogeneic hematopoietic stem cell transplantation.

    Science.gov (United States)

    Murase, Kazuyuki; Kim, Haesook T; Bascug, O R Gregory; Kawano, Yutaka; Ryan, Jeremy; Matsuoka, Ken-ichi; Davids, Matthew S; Koreth, John; Ho, Vincent T; Cutler, Corey; Armand, Philippe; Alyea, Edwin P; Blazar, Bruce R; Antin, Joseph H; Soiffer, Robert J; Letai, Anthony; Ritz, Jerome

    2014-09-01

    CD4 regulatory T cells play a critical role in establishment of immune tolerance and prevention of graft-versus-host disease after allogeneic hematopoietic stem cell transplantation. The recovery and maintenance of regulatory T cells is dependent on homeostatic factors including the generation of naïve regulatory T cells from hematopoietic precursor cells, the proliferation and expansion of mature regulatory T cells, and the survival of regulatory T cells in vivo. In this study, quantitation of mitochondrial apoptotic priming was used to compare susceptibility of regulatory T cells, conventional CD4 T cells and CD8 T cells to intrinsic pathway apoptosis in 57 patients after allogeneic hematopoietic stem cell transplantation and 25 healthy donors. In healthy donors, regulatory T cells are more susceptible to mitochondrial priming than conventional T cells. Mitochondrial priming is increased after hematopoietic stem cell transplantation in all T-cell subsets and particularly in patients with chronic graft-versus-host disease. Regulatory T cells express high levels of CD95 and are also more susceptible than conventional T cells to apoptosis through the extrinsic pathway. However, CD95 expression and extrinsic pathway apoptosis is not increased after hematopoietic stem cell transplantation. Decreased expression of BCL2 and increased expression of BIM, a mitochondrial cell death activator protein, in regulatory T cells contributes to increased mitochondrial priming in this T-cell subset but additional factors likely contribute to increased mitochondrial priming following hematopoietic stem cell transplantation. Copyright© Ferrata Storti Foundation.

  5. A comparison of mitochondrial DNA isolation methods in frozen post-mortem human brain tissue--applications for studies of mitochondrial genetics in brain disorders.

    Science.gov (United States)

    Devall, Matthew; Burrage, Joe; Caswell, Richard; Johnson, Matthew; Troakes, Claire; Al-Sarraj, Safa; Jeffries, Aaron R; Mill, Jonathan; Lunnon, Katie

    2015-10-01

    Given that many brain disorders are characterized by mitochondrial dysfunction, there is a growing interest in investigating genetic and epigenetic variation in mitochondrial DNA (mtDNA). One major caveat for such studies is the presence of nuclear-mitochondrial pseudogenes (NUMTs), which are regions of the mitochondrial genome that have been inserted into the nuclear genome over evolution and, if not accounted for, can confound genetic studies of mtDNA. Here we provide the first systematic comparison of methods for isolating mtDNA from frozen post-mortem human brain tissue. Our data show that a commercial method from Miltenyi Biotec, which magnetically isolates mitochondria using antibodies raised against the mitochondrial import receptor subunit TOM22, gives significant mtDNA enrichment and should be considered the method of choice for mtDNA studies in frozen brain tissue.

  6. Nicotine induces mitochondrial fission through mitofusin degradation in human multipotent embryonic carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Hirata, Naoya; Yamada, Shigeru [Division of Pharmacology, National Institute of Health Sciences (Japan); Asanagi, Miki [Division of Pharmacology, National Institute of Health Sciences (Japan); Faculty of Engineering, Department of Materials Science and Engineering, Yokohama National University (Japan); Sekino, Yuko [Division of Pharmacology, National Institute of Health Sciences (Japan); Kanda, Yasunari, E-mail: kanda@nihs.go.jp [Division of Pharmacology, National Institute of Health Sciences (Japan)

    2016-02-05

    Nicotine is considered to contribute to the health risks associated with cigarette smoking. Nicotine exerts its cellular functions by acting on nicotinic acetylcholine receptors (nAChRs), and adversely affects normal embryonic development. However, nicotine toxicity has not been elucidated in human embryonic stage. In the present study, we examined the cytotoxic effects of nicotine in human multipotent embryonal carcinoma cell line NT2/D1. We found that exposure to 10 μM nicotine decreased intracellular ATP levels and inhibited proliferation of NT2/D1 cells. Because nicotine suppressed energy production, which is a critical mitochondrial function, we further assessed the effects of nicotine on mitochondrial dynamics. Staining with MitoTracker revealed that 10 μM nicotine induced mitochondrial fragmentation. The levels of the mitochondrial fusion proteins, mitofusins 1 and 2, were also reduced in cells exposed to nicotine. These nicotine effects were blocked by treatment with mecamylamine, a nonselective nAChR antagonist. These data suggest that nicotine degrades mitofusin in NT2/D1 cells and thus induces mitochondrial dysfunction and cell growth inhibition in a nAChR-dependent manner. Thus, mitochondrial function in embryonic cells could be used to assess the developmental toxicity of chemicals.

  7. Fat metabolism during exercise in patients with mitochondrial disease

    DEFF Research Database (Denmark)

    Jeppesen, Tina Dysgaard; Orngreen, Mette Cathrine; Van Hall, Gerrit

    2009-01-01

    OBJECTIVE: To determine whether patients with defects of the respiratory chain have metabolic adaptations that promote a preferential use of fats or carbohydrates, similar to what is observed in metabolic myopathies affecting glycolysis or fat oxidation. DESIGN: Causation and case-control study....... Fat metabolism was determined by means of indirect calorimetry and stable isotope technique in patients and healthy subjects. Patients carried various types and loads (mean [SE], 72% [5%]) of mitochondrial DNA (mtDNA) mutations in skeletal muscle. All subjects exercised at the same absolute workload...

  8. Mitochondrial modulators improve lipid composition and attenuate memory deficits in experimental model of Huntington's disease.

    Science.gov (United States)

    Mehrotra, Arpit; Sood, Abhilasha; Sandhir, Rajat

    2015-12-01

    3-Nitropropionic acid (3-NP) is an irreversible inhibitor of succinate dehydrogenase and induces neuropathological changes similar to those observed in Huntington's disease (HD). The objective of the present study was to investigate neuroprotective effect of mitochondrial modulators; alpha-lipoic acid (ALA) and acetyl-L-carnitine (ALCAR) on 3-NP-induced alterations in mitochondrial lipid composition, mitochondrial structure and memory functions. Experimental model of HD was developed by administering 3-NP at sub-chronic doses, twice daily for 17 days. The levels of conjugated dienes, cholesterol and glycolipids were significantly increased, whereas the levels of phospholipids (phosphatidylethanolamine, phosphatidylcholine, phosphatidylserine) including cardiolipin were significantly decreased in the mitochondria isolated from the striatum of 3-NP-treated animals. In addition, the difference in molecular composition of each phospholipid class was also evaluated using mass spectrometry. Mitochondria lipid from 3-NP-treated animals showed increased cholesterol to phospholipid ratio, suggesting decreased mitochondrial membrane fluidity. 3-NP administration also resulted in ultra-structural changes in mitochondria, accompanied by swelling as assessed by transmission electron microscopy. The 3-NP administered animals had impaired spatial memory evaluated using elevated plus maze test. However, combined supplementation with ALA + ALCAR for 21 days normalized mitochondrial lipid composition, improved mitochondrial structure and ameliorated memory impairments in 3-NP-treated animals, suggesting an imperative role of these two modulators in combination in the management of HD.

  9. Ketamine Causes Mitochondrial Dysfunction in Human Induced Pluripotent Stem Cell-Derived Neurons

    Science.gov (United States)

    Ito, Hiroyuki; Uchida, Tokujiro; Makita, Koshi

    2015-01-01

    Purpose Ketamine toxicity has been demonstrated in nonhuman mammalian neurons. To study the toxic effect of ketamine on human neurons, an experimental model of cultured neurons from human induced pluripotent stem cells (iPSCs) was examined, and the mechanism of its toxicity was investigated. Methods Human iPSC-derived dopaminergic neurons were treated with 0, 20, 100 or 500 μM ketamine for 6 and 24 h. Ketamine toxicity was evaluated by quantification of caspase 3/7 activity, reactive oxygen species (ROS) production, mitochondrial membrane potential, ATP concentration, neurotransmitter reuptake activity and NADH/NAD+ ratio. Mitochondrial morphological change was analyzed by transmission electron microscopy and confocal microscopy. Results Twenty-four-hour exposure of iPSC-derived neurons to 500 μM ketamine resulted in a 40% increase in caspase 3/7 activity (P ketamine (100 μM) decreased the ATP level (22%, P ketamine concentration, which suggests that mitochondrial dysfunction preceded ROS generation and caspase activation. Conclusions We established an in vitro model for assessing the neurotoxicity of ketamine in iPSC-derived neurons. The present data indicate that the initial mitochondrial dysfunction and autophagy may be related to its inhibitory effect on the mitochondrial electron transport system, which underlies ketamine-induced neural toxicity. Higher ketamine concentration can induce ROS generation and apoptosis in human neurons. PMID:26020236

  10. Comparative study of human mitochondrial proteome reveals extensive protein subcellular relocalization after gene duplications

    Directory of Open Access Journals (Sweden)

    Huang Yong

    2009-11-01

    Full Text Available Abstract Background Gene and genome duplication is the principle creative force in evolution. Recently, protein subcellular relocalization, or neolocalization was proposed as one of the mechanisms responsible for the retention of duplicated genes. This hypothesis received support from the analysis of yeast genomes, but has not been tested thoroughly on animal genomes. In order to evaluate the importance of subcellular relocalizations for retention of duplicated genes in animal genomes, we systematically analyzed nuclear encoded mitochondrial proteins in the human genome by reconstructing phylogenies of mitochondrial multigene families. Results The 456 human mitochondrial proteins selected for this study were clustered into 305 gene families including 92 multigene families. Among the multigene families, 59 (64% consisted of both mitochondrial and cytosolic (non-mitochondrial proteins (mt-cy families while the remaining 33 (36% were composed of mitochondrial proteins (mt-mt families. Phylogenetic analyses of mt-cy families revealed three different scenarios of their neolocalization following gene duplication: 1 relocalization from mitochondria to cytosol, 2 from cytosol to mitochondria and 3 multiple subcellular relocalizations. The neolocalizations were most commonly enabled by the gain or loss of N-terminal mitochondrial targeting signals. The majority of detected subcellular relocalization events occurred early in animal evolution, preceding the evolution of tetrapods. Mt-mt protein families showed a somewhat different pattern, where gene duplication occurred more evenly in time. However, for both types of protein families, most duplication events appear to roughly coincide with two rounds of genome duplications early in vertebrate evolution. Finally, we evaluated the effects of inaccurate and incomplete annotation of mitochondrial proteins and found that our conclusion of the importance of subcellular relocalization after gene duplication on

  11. Effect of Remifentanil on Mitochondrial Oxygen Consumption of Cultured Human Hepatocytes

    Science.gov (United States)

    Djafarzadeh, Siamak; Vuda, Madhusudanarao; Takala, Jukka; Jakob, Stephan M.

    2012-01-01

    During sepsis, liver dysfunction is common, and failure of mitochondria to effectively couple oxygen consumption with energy production has been described. In addition to sepsis, pharmacological agents used to treat septic patients may contribute to mitochondrial dysfunction. This study addressed the hypothesis that remifentanil interacts with hepatic mitochondrial oxygen consumption. The human hepatoma cell line HepG2 and their isolated mitochondria were exposed to remifentanil, with or without further exposure to tumor necrosis factor-α (TNF-α). Mitochondrial oxygen consumption was measured by high-resolution respirometry, Caspase-3 protein levels by Western blotting, and cytokine levels by ELISA. Inhibitory κBα (IκBα) phosphorylation, measurement of the cellular ATP content and mitochondrial membrane potential in intact cells were analysed using commercial ELISA kits. Maximal cellular respiration increased after one hour of incubation with remifentanil, and phosphorylation of IκBα occurred, denoting stimulation of nuclear factor κB (NF-κB). The effect on cellular respiration was not present at 2, 4, 8 or 16 hours of incubation. Remifentanil increased the isolated mitochondrial respiratory control ratio of complex-I-dependent respiration without interfering with maximal respiration. Preincubation with the opioid receptor antagonist naloxone prevented a remifentanil-induced increase in cellular respiration. Remifentanil at 10× higher concentrations than therapeutic reduced mitochondrial membrane potential and ATP content without uncoupling oxygen consumption and basal respiration levels. TNF-α exposure reduced respiration of complex-I, -II and -IV, an effect which was prevented by prior remifentanil incubation. Furthermore, prior remifentanil incubation prevented TNF-α-induced IL-6 release of HepG2 cells, and attenuated fragmentation of pro-caspase-3 into cleaved active caspase 3 (an early marker of apoptosis). Our data suggest that remifentanil

  12. Effect of remifentanil on mitochondrial oxygen consumption of cultured human hepatocytes.

    Directory of Open Access Journals (Sweden)

    Siamak Djafarzadeh

    Full Text Available During sepsis, liver dysfunction is common, and failure of mitochondria to effectively couple oxygen consumption with energy production has been described. In addition to sepsis, pharmacological agents used to treat septic patients may contribute to mitochondrial dysfunction. This study addressed the hypothesis that remifentanil interacts with hepatic mitochondrial oxygen consumption. The human hepatoma cell line HepG2 and their isolated mitochondria were exposed to remifentanil, with or without further exposure to tumor necrosis factor-α (TNF-α. Mitochondrial oxygen consumption was measured by high-resolution respirometry, Caspase-3 protein levels by Western blotting, and cytokine levels by ELISA. Inhibitory κBα (IκBα phosphorylation, measurement of the cellular ATP content and mitochondrial membrane potential in intact cells were analysed using commercial ELISA kits. Maximal cellular respiration increased after one hour of incubation with remifentanil, and phosphorylation of IκBα occurred, denoting stimulation of nuclear factor κB (NF-κB. The effect on cellular respiration was not present at 2, 4, 8 or 16 hours of incubation. Remifentanil increased the isolated mitochondrial respiratory control ratio of complex-I-dependent respiration without interfering with maximal respiration. Preincubation with the opioid receptor antagonist naloxone prevented a remifentanil-induced increase in cellular respiration. Remifentanil at 10× higher concentrations than therapeutic reduced mitochondrial membrane potential and ATP content without uncoupling oxygen consumption and basal respiration levels. TNF-α exposure reduced respiration of complex-I, -II and -IV, an effect which was prevented by prior remifentanil incubation. Furthermore, prior remifentanil incubation prevented TNF-α-induced IL-6 release of HepG2 cells, and attenuated fragmentation of pro-caspase-3 into cleaved active caspase 3 (an early marker of apoptosis. Our data suggest that

  13. Mitochondrial signaling pathway in Alzheimer´s disease: disclosure of new therapeutic targets

    OpenAIRE

    Silva, Diana Filipa Ferreira da

    2014-01-01

    Tese de doutoramento em Biociências, apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra The etiology of sporadic Alzheimer´s disease remains largely unknown. Data from literature show that a bioenergetics failure, especially due to mitochondrial dysfunction, is a common event in Alzheimer’s disease and mild cognitive impairment, a clinical syndrome that frequently precedes symptomatic Alzheimer´s disease. Mitochondria play a pivotal role in cellular metabolism sinc...

  14. Post-Translational Modifications of Cardiac Mitochondrial Proteins in Cardiovascular Disease: Not Lost in Translation.

    Science.gov (United States)

    Marquez, Jubert; Lee, Sung Ryul; Kim, Nari; Han, Jin

    2016-01-01

    Protein post-translational modifications (PTMs) are crucial in regulating cellular biology by playing key roles in processes such as the rapid on and off switching of signaling network and the regulation of enzymatic activities without affecting gene expressions. PTMs lead to conformational changes in the tertiary structure of protein and resultant regulation of protein function such as activation, inhibition, or signaling roles. PTMs such as phosphorylation, acetylation, and S-nitrosylation of specific sites in proteins have key roles in regulation of mitochondrial functions, thereby contributing to the progression to heart failure. Despite the extensive study of PTMs in mitochondrial proteins much remains unclear. Further research is yet to be undertaken to elucidate how changes in the proteins may lead to cardiovascular and metabolic disease progression in particular. We aimed to summarize the various types of PTMs that occur in mitochondrial proteins, which might be associated with heart failure. This study will increase the understanding of cardiovascular diseases through PTM.

  15. Epigenetic regulation of mitochondrial function in neurodegenerative disease: New insights from advances in genomic technologies.

    Science.gov (United States)

    Devall, Matthew; Roubroeks, Janou; Mill, Jonathan; Weedon, Michael; Lunnon, Katie

    2016-06-20

    The field of mitochondrial epigenetics has received increased attention in recent years and changes in mitochondrial DNA (mtDNA) methylation has been implicated in a number of diseases, including neurodegenerative diseases such as amyotrophic lateral sclerosis. However, current publications have been limited by the use of global or targeted methods of measuring DNA methylation. In this review, we discuss current findings in mitochondrial epigenetics as well as its potential role as a regulator of mitochondria within the brain. Finally, we summarize the current technologies best suited to capturing mtDNA methylation, and how a move towards whole epigenome sequencing of mtDNA may help to advance our current understanding of the field. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. Reduction in mitochondrial DNA copy number in peripheral leukocytes after onset of Huntington's disease

    DEFF Research Database (Denmark)

    Petersen, Maria Hvidberg; Budtz-Jørgensen, Esben; Sørensen, Sven Asger

    2014-01-01

    Huntington's disease (HD) is an inherited neurodegenerative disorder characterised by movement disorder, cognitive symptoms and psychiatric symptoms with predominantly adult-onset. The mutant huntingtin protein leads to mitochondrial dysfunction in blood leukocytes. This discovery led to the inve......Huntington's disease (HD) is an inherited neurodegenerative disorder characterised by movement disorder, cognitive symptoms and psychiatric symptoms with predominantly adult-onset. The mutant huntingtin protein leads to mitochondrial dysfunction in blood leukocytes. This discovery led...... to the investigation of the mitochondrial DNA (mtDNA) copy number relative to nuclear DNA (nDNA) in leukocytes from carriers of the HD mutation compared to healthy individuals. We found significantly reduced mtDNA/nDNA in HD mutation carriers compared to controls. A longitudinal study of archive DNA sample pairs from...

  17. Nexus between mitochondrial function, iron, copper and glutathione in Parkinson's disease.

    Science.gov (United States)

    Liddell, Jeffrey R; White, Anthony R

    2017-05-31

    Parkinson's disease is neuropathologically characterised by loss of catecholamine neurons in vulnerable brain regions including substantia nigra pars compacta and locus coeruleus. This review discusses how the susceptibility of these regions is defined by their shared biochemical characteristics that differentiate them from other neurons. Parkinson's disease is biochemically characterised by mitochondrial dysfunction, accumulation of iron, diminished copper content and depleted glutathione levels in these regions. This review also discusses this neuropathology, and provides evidence for how these pathological features are mechanistically linked to each other. This leads to the conclusion that disruption of mitochondrial function, or iron, copper or glutathione metabolism in isolation provokes the pathological impairment of them all. This creates a vicious cycle that drives pathology leading to mitochondrial failure and neuronal cell death in vulnerable brain regions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Metabolic profiles of exercise in patients with McArdle disease or mitochondrial myopathy.

    Science.gov (United States)

    Delaney, Nigel F; Sharma, Rohit; Tadvalkar, Laura; Clish, Clary B; Haller, Ronald G; Mootha, Vamsi K

    2017-08-01

    McArdle disease and mitochondrial myopathy impair muscle oxidative phosphorylation (OXPHOS) by distinct mechanisms: the former by restricting oxidative substrate availability caused by blocked glycogen breakdown, the latter because of intrinsic respiratory chain defects. We applied metabolic profiling to systematically interrogate these disorders at rest, when muscle symptoms are typically minimal, and with exercise, when symptoms of premature fatigue and potential muscle injury are unmasked. At rest, patients with mitochondrial disease exhibit elevated lactate and reduced uridine; in McArdle disease purine nucleotide metabolites, including xanthine, hypoxanthine, and inosine are elevated. During exercise, glycolytic intermediates, TCA cycle intermediates, and pantothenate expand dramatically in both mitochondrial disease and control subjects. In contrast, in McArdle disease, these metabolites remain unchanged from rest; but urea cycle intermediates are increased, likely attributable to increased ammonia production as a result of exaggerated purine degradation. Our results establish skeletal muscle glycogen as the source of TCA cycle expansion that normally accompanies exercise and imply that impaired TCA cycle flux is a central mechanism of restricted oxidative capacity in this disorder. Finally, we report that resting levels of long-chain triacylglycerols in mitochondrial myopathy correlate with the severity of OXPHOS dysfunction, as indicated by the level of impaired O 2 extraction from arterial blood during peak exercise. Our integrated analysis of exercise and metabolism provides unique insights into the biochemical basis of these muscle oxidative defects, with potential implications for their clinical management.

  19. Cockayne syndrome group B protein promotes mitochondrial DNA stability by supporting the DNA repair association with the mitochondrial membrane

    National Research Council Canada - National Science Library

    Aamann, Maria D; Sorensen, Martin M; Hvitby, Christina; Berquist, Brian R; Muftuoglu, Meltem; Tian, Jingyan; de Souza-Pinto, Nadja C; Scheibye-Knudsen, Morten; Wilson, 3rd, David M; Stevnsner, Tinna; Bohr, Vilhelm A

    2010-01-01

    Cockayne syndrome (CS) is a human premature aging disorder associated with severe developmental deficiencies and neurodegeneration, and phenotypically it resembles some mitochondrial DNA (mtDNA) diseases...

  20. Analysis of mitochondrial DNA sequences in childhood encephalomyopathies reveals new disease-associated variants.

    Directory of Open Access Journals (Sweden)

    Aijaz A Wani

    Full Text Available BACKGROUND: Mitochondrial encephalomyopathies are a heterogeneous group of clinical disorders generally caused due to mutations in either mitochondrial DNA (mtDNA or nuclear genes encoding oxidative phosphorylation (OXPHOS. We analyzed the mtDNA sequences from a group of 23 pediatric patients with clinical and morphological features of mitochondrial encephalopathies and tried to establish a relationship of identified variants with the disease. METHODOLOGY/PRINCIPLE FINDINGS: Complete mitochondrial genomes were amplified by PCR and sequenced by automated DNA sequencing. Sequencing data was analyzed by SeqScape software and also confirmed by BLASTn program. Nucleotide sequences were compared with the revised Cambridge reference sequence (CRS and sequences present in mitochondrial databases. The data obtained shows that a number of known and novel mtDNA variants were associated with the disease. Most of the non-synonymous variants were heteroplasmic (A4136G, A9194G and T11916A suggesting their possibility of being pathogenic in nature. Some of the missense variants although homoplasmic were showing changes in highly conserved amino acids (T3394C, T3866C, and G9804A and were previously identified with diseased conditions. Similarly, two other variants found in tRNA genes (G5783A and C8309T could alter the secondary structure of Cys-tRNA and Lys-tRNA. Most of the variants occurred in single cases; however, a few occurred in more than one case (e.g. G5783A and A10149T. CONCLUSIONS AND SIGNIFICANCE: The mtDNA variants identified in this study could be the possible cause of mitochondrial encephalomyopathies with childhood onset in the patient group. Our study further strengthens the pathogenic score of known variants previously reported as provisionally pathogenic in mitochondrial diseases. The novel variants found in the present study can be potential candidates for further investigations to establish the relationship between their incidence and role

  1. Naringin ameliorates memory deficits in experimental paradigm of Alzheimer's disease by attenuating mitochondrial dysfunction.

    Science.gov (United States)

    Sachdeva, Anand Kamal; Kuhad, Anurag; Chopra, Kanwaljit

    2014-12-01

    Mitochondrial dysfunction has been well documented in age related disorders like Alzheimer's disease. Alterations in mitochondrial membrane potential lead to neuronal death by excessive generation of free radicals, inflammatory cytokines, and excitotoxins. Intracerebroventricular (ICV) streptozotocin (STZ) induced-cognitive impairment has been widely used as an experimental model of Alzheimer's disease. Naringin is a potent antioxidant, which can cross the blood brain barrier protecting brain tissue and modulating brain chemistry. The present study was designed to evaluate the effect of naringin, in ICV STZ-induced mitochondrial dysfunction and memory loss in rats. Streptozotocin (3mg/kg, ICV) was injected bilaterally in two divided doses on first and third day followed by treatment with different doses of naringin (50, 100 and 200mg/kg; p.o.) for twenty one days. Behavioral alterations were monitored using Morris water maze paradigm and elevated plus maze test. Animals were sacrificed to evaluate various biochemical and mitochondrial parameters in brain. Rivastigmine was used as a standard drug. ICV-STZ administration produced significant cognitive deficits as assessed by both Morris water maze and elevated plus maze task which is accompanied by significantly enhanced oxidative-nitrosative stress, altered acetylcholinesterase and mitochondrial enzyme activities in cerebral cortex and hippocampus of rats brain along with significantly increased brain TNF-α and IL-1β levels. Chronic treatment with naringin dose dependently restored cognitive deficits in ICV-STZ rat along with mitigation of mitochondrial dysfunction mediated oxido-nitrosative stress and cytokine release. Our findings demonstrate that naringin ameliorates mitochondrial dysfunction mediated oxido-nitrosative stress and inflammatory surge in ICV-STZ rats. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Extensive respiratory chain defects in inhibitory interneurones in patients with mitochondrial disease.

    Science.gov (United States)

    Lax, Nichola Z; Grady, John; Laude, Alex; Chan, Felix; Hepplewhite, Philippa D; Gorman, Grainne; Whittaker, Roger G; Ng, Yi; Cunningham, Mark O; Turnbull, Doug M

    2016-02-01

    Mitochondrial disorders are among the most frequently inherited cause of neurological disease and arise due to mutations in mitochondrial or nuclear DNA. Currently, we do not understand the specific involvement of certain brain regions or selective neuronal vulnerability in mitochondrial disease. Recent studies suggest γ-aminobutyric acid (GABA)-ergic interneurones are particularly susceptible to respiratory chain dysfunction. In this neuropathological study, we assess the impact of mitochondrial DNA defects on inhibitory interneurones in patients with mitochondrial disease. Histochemical, immunohistochemical and immunofluorescent assays were performed on post-mortem brain tissue from 10 patients and 10 age-matched control individuals. We applied a quantitative immunofluorescent method to interrogate complex I and IV protein expression in mitochondria within GABAergic interneurone populations in the frontal, temporal and occipital cortices. We also evaluated the density of inhibitory interneurones in serial sections to determine if cell loss was occurring. We observed significant, global reductions in complex I expression within GABAergic interneurones in frontal, temporal and occipital cortices in the majority of patients. While complex IV expression is more variable, there is reduced expression in patients harbouring m.8344A>G point mutations and POLG mutations. In addition to the severe respiratory chain deficiencies observed in remaining interneurones, quantification of GABAergic cell density showed a dramatic reduction in cell density suggesting interneurone loss. We propose that the combined loss of interneurones and severe respiratory deficiency in remaining interneurones contributes to impaired neuronal network oscillations and could underlie development of neurological deficits, such as cognitive impairment and epilepsy, in mitochondrial disease. © 2015 The Authors. Neuropathology and Applied Neurobiology published by John Wiley & Sons Ltd on behalf of

  3. PINK1 signalling rescues amyloid pathology and mitochondrial dysfunction in Alzheimer's disease.

    Science.gov (United States)

    Du, Fang; Yu, Qing; Yan, Shijun; Hu, Gang; Lue, Lih-Fen; Walker, Douglas G; Wu, Long; Yan, Shi Fang; Tieu, Kim; Yan, Shirley ShiDu

    2017-12-01

    Mitochondrial dysfunction and synaptic damage are early pathological features of the Alzheimer's disease-affected brain. Memory impairment in Alzheimer's disease is a manifestation of brain pathologies such as accumulation of amyloid-β peptide and mitochondrial damage. The underlying pathogenic mechanisms and effective disease-modifying therapies for Alzheimer's disease remain elusive. Here, we demonstrate for the first time that decreased PTEN-induced putative kinase 1 (PINK1) expression is associated with Alzheimer's disease pathology. Restoring neuronal PINK1 function strikingly reduces amyloid-β levels, amyloid-associated pathology, oxidative stress, as well as mitochondrial and synaptic dysfunction. In contrast, PINK1-deficient mAPP mice augmented cerebral amyloid-β accumulation, mitochondrial abnormalities, impairments in learning and memory, as well as synaptic plasticity at an earlier age than mAPP mice. Notably, gene therapy-mediated PINK1 overexpression promotes the clearance of damaged mitochondria by augmenting autophagy signalling via activation of autophagy receptors (OPTN and NDP52), thereby alleviating amyloid-β-induced loss of synapses and cognitive decline in Alzheimer's disease mice. Loss of PINK1 activity or blockade of PINK1-mediated signalling (OPTN or NDP52) fails to reverse amyloid-β-induced detrimental effects. Our findings highlight a novel mechanism by which PINK1-dependent signalling promotes the rescue of amyloid pathology and amyloid-β-mediated mitochondrial and synaptic dysfunctions in a manner requiring activation of autophagy receptor OPTN or NDP52. Thus, activation of PINK1 may represent a new therapeutic avenue for combating Alzheimer's disease. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. [Mitochondrial DNA polymorphisms shared between modern humans and neanderthals: adaptive convergence or evidence for interspecific hybridization?].

    Science.gov (United States)

    Maliarchuk, B A

    2013-09-01

    An analysis of the variability of the nucleotide sequences in the mitochondrial genome of modern humans, neanderthals, Denisovans, and other primates has shown that there are shared polymorphisms at positions 2758 and 7146 between modern Homo sapiens (in phylogenetic cluster L2'3'4'5'6) and Homo neanderthalensis (in the group of European neanderthals younger than 48000 years). It is suggested that the convergence may be due to adaptive changes in the mitochondrial genomes of modern humans and neanderthals or interspecific hybridization associated with mtDNA recombination.

  5. Complex forms of mitochondrial DNA in human B cells transformed by Epstein-Barr virus (EBV)

    DEFF Research Database (Denmark)

    Christiansen, Gunna; Christiansen, C; Zeuthen, J

    1983-01-01

    Human lymphocytes and lymphoid cell lines were analyzed for the presence of complex forms of mitochondrial DNA (mtDNA) by electron microscopy. A high frequency (9%-14.5%) of catenated dimers, circular dimers, or oligomers were found in samples from Epstein-Barr-virus-(EBV) transformed lymphoblast......Human lymphocytes and lymphoid cell lines were analyzed for the presence of complex forms of mitochondrial DNA (mtDNA) by electron microscopy. A high frequency (9%-14.5%) of catenated dimers, circular dimers, or oligomers were found in samples from Epstein-Barr-virus-(EBV) transformed...

  6. All-Trans-Retinoic Acid Enhances Mitochondrial Function in Models of Human Liver

    OpenAIRE

    Tripathy, Sasmita; Chapman, John D.; Han, Chang Y; Hogarth, Cathryn A.; Arnold, Samuel L. M.; Onken, Jennifer; Kent, Travis; Goodlett, David R.; Isoherranen, Nina

    2016-01-01

    All-trans-retinoic acid (atRA) is the active metabolite of vitamin A. The liver is the main storage organ of vitamin A, but activation of the retinoic acid receptors (RARs) in mouse liver and in human liver cell lines has also been shown. Although atRA treatment improves mitochondrial function in skeletal muscle in rodents, its role in modulating mitochondrial function in the liver is controversial, and little data are available regarding the human liver. The aim of this study was to determin...

  7. Mitochondrial abnormalities related to the dysfunction of circulating endothelial colony-forming cells in moyamoya disease.

    Science.gov (United States)

    Choi, Jung Won; Son, Sung Min; Mook-Jung, Inhee; Moon, Youn Joo; Lee, Ji Yeoun; Wang, Kyu-Chang; Kang, Hyun-Seung; Phi, Ji Hoon; Choi, Seung Ah; Chong, Sangjoon; Byun, Jayoung; Kim, Seung-Ki

    2017-12-08

    OBJECTIVE Moyamoya disease (MMD) is a unique cerebrovascular disorder characterized by the progressive occlusion of the bilateral internal carotid arteries. Endothelial colony-forming cells (ECFCs), previously termed "endothelial progenitor cells," play an important role in the pathogenesis of MMD. In this study, the authors performed morphological and functional studies of the mitochondria of ECFCs from patients with MMD to present new insights into the pathogenesis of the disease. METHODS The morphology of ECFCs from 5 MMD patients and 5 healthy controls was examined under both a transmission electron microscope and a confocal laser scanning microscope. The oxygen consumption rates (OCRs), mitochondrial membrane potentials (MMPs), intracellular Ca2+ concentrations, mitochondrial enzyme activities, and reactive oxygen species (ROS) levels were measured. Functional activity of the ECFCs was evaluated using a capillary tube formation assay. RESULTS The ECFCs from the MMD patients displayed a disrupted mitochondrial morphology, including a shorter and more circular shape. The ECFC mitochondria from the MMD patients exhibited functional abnormalities, which were assessed as a decreased OCR and an increased intracellular Ca2+ concentration. Moreover, the ECFCs from MMD patients showed increased ROS levels. Interestingly, treatment with an ROS scavenger not only reversed the mitochondrial abnormalities but also restored the angiogenic activity of the ECFCs from the MMD patients. CONCLUSIONS The mitochondria of ECFCs from MMD patients, as compared with those from healthy patients, exhibited morphological and functional abnormalities. This finding suggests that the mitochondrial abnormalities may have a role in the pathogenesis of MMD.

  8. 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.

  9. Disease consequences of human adaptation

    Directory of Open Access Journals (Sweden)

    Justin C. Fay

    2013-12-01

    Full Text Available Adaptive evolution has provided us with a unique set of characteristics that define us as humans, including morphological, physiological and cellular changes. Yet, natural selection provides no assurances that adaptation is without human health consequences; advantageous mutations will increase in frequency so long as there is a net gain in fitness. As such, the current incidence of human disease can depend on previous adaptations. Here, I review genome-wide and gene-specific studies in which adaptive evolution has played a role in shaping human genetic disease. In addition to the disease consequences of adaptive phenotypes, such as bipedal locomotion and resistance to certain pathogens, I review evidence that adaptive mutations have influenced the frequency of linked disease alleles through genetic hitchhiking. Taken together, the links between human adaptation and disease highlight the importance of their combined influence on functional variation within the human genome and offer opportunities to discover and characterize such variation.

  10. Mitochondrial Molecular Pathophysiology of Nonalcoholic Fatty Liver Disease: A Proteomics Approach

    Directory of Open Access Journals (Sweden)

    Natalia Nuño-Lámbarri

    2016-03-01

    Full Text Available Nonalcoholic fatty liver disease (NAFLD is a chronic liver condition that can progress to nonalcoholic steatohepatitis, cirrhosis and cancer. It is considered an emerging health problem due to malnourishment or a high-fat diet (HFD intake, which is observed worldwide. It is well known that the hepatocytes’ apoptosis phenomenon is one of the most important features of NAFLD. Thus, this review focuses on revealing, through a proteomics approach, the complex network of protein interactions that promote fibrosis, liver cell stress, and apoptosis. According to different types of in vitro and murine models, it has been found that oxidative/nitrative protein stress leads to mitochondrial dysfunction, which plays a major role in stimulating NAFLD damage. Human studies have revealed the importance of novel biomarkers, such as retinol-binding protein 4, lumican, transgelin 2 and hemoglobin, which have a significant role in the disease. The post-genome era has brought proteomics technology, which allows the determination of molecular pathogenesis in NAFLD. This has led to the search for biomarkers which improve early diagnosis and optimal treatment and which may effectively prevent fatal consequences such as cirrhosis or cancer.

  11. [Recent progress of mitochondrial quality control in ischemic heart disease and its role in cardio-protection of vagal nerve].

    Science.gov (United States)

    Xue, Run-Qing; Xu, Man; Yu, Xiao-Jiang; Liu, Long-Zhu; Zang, Wei-Jin

    2017-10-25

    Ischemic heart disease (IHD) is the life-threatening cardiovascular disease. Mitochondria have emerged as key participants and regulators of cellular energy demands and signal transduction. Mitochondrial quality is controlled by a number of coordinated mechanisms including mitochondrial fission, fusion and mitophagy, which plays an important role in maintaining healthy mitochondria and cardiac function. Recently, dysfunction of each process in mitochondrial quality control has been observed in the ischemic hearts. This review describes the mechanism of mitochondrial dynamics and mitophagy as well as its performance linked to myocardial ischemia. Moreover, in combination with our study, we will discuss the effect of vagal nerve on mitochondria in cardio-protection.

  12. Metabolites from invasive pests inhibit mitochondrial complex II: A potential strategy for the treatment of human ovarian carcinoma?

    Energy Technology Data Exchange (ETDEWEB)

    Ferramosca, Alessandra, E-mail: alessandra.ferramosca@unisalento.it [Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, Lecce (Italy); Conte, Annalea; Guerra, Flora; Felline, Serena [Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, Lecce (Italy); Rimoli, Maria Grazia [Dipartimento di Farmacia, Università di Napoli Federico II, Napoli (Italy); Mollo, Ernesto [Istituto di Chimica Biomolecolare, Consiglio Nazionale delle Ricerche, Pozzuoli (Italy); Zara, Vincenzo [Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, Lecce (Italy); Terlizzi, Antonio [Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, Lecce (Italy); Stazione Zoologica Anton Dohrn, Napoli (Italy)

    2016-05-13

    The red pigment caulerpin, a secondary metabolite from the marine invasive green algae Caulerpa cylindracea can be accumulated and transferred along the trophic chain, with detrimental consequences on biodiversity and ecosystem functioning. Despite increasing research efforts to understand how caulerpin modifies fish physiology, little is known on the effects of algal metabolites on mammalian cells. Here we report for the first time the mitochondrial targeting activity of both caulerpin, and its closely related derivative caulerpinic acid, by using as experimental model rat liver mitochondria, a system in which bioenergetics mechanisms are not altered. Mitochondrial function was tested by polarographic and spectrophotometric methods. Both compounds were found to selectively inhibit respiratory complex II activity, while complexes I, III, and IV remained functional. These results led us to hypothesize that both algal metabolites could be used as antitumor agents in cell lines with defects in mitochondrial complex I. Ovarian cancer cisplatin-resistant cells are a good example of cell lines with a defective complex I function on which these molecules seem to have a toxic effect on proliferation. This provided novel insight toward the potential use of metabolites from invasive Caulerpa species for the treatment of human ovarian carcinoma cisplatin-resistant cells. -- Highlights: •Novel insight toward the potential use of the algal metabolites for the treatment of human diseases. •Caulerpin and caulerpinic acid inhibit respiratory complex II activity. •Both algal metabolites could be used as antitumor agents in ovarian cancer cisplatin-resistant cells.

  13. Depletion of mitochondrial fission factor DRP1 causes increased apoptosis in human colon cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Inoue-Yamauchi, Akane, E-mail: ainoyama@research.twmu.ac.jp [Department of Pathology, Tokyo Women' s Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666 (Japan); Oda, Hideaki [Department of Pathology, Tokyo Women' s Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666 (Japan)

    2012-04-27

    Highlights: Black-Right-Pointing-Pointer DRP1 is required for mitochondrial fission in colon cancer cells. Black-Right-Pointing-Pointer DRP1 participates in inhibition of colon cancer cell apoptosis. Black-Right-Pointing-Pointer DRP1 can inhibit apoptosis through the regulation of cytochrome c release. -- Abstract: Mitochondria play a critical role in regulation of apoptosis, a form of programmed cell death, by releasing apoptogenic factors including cytochrome c. Growing evidence suggests that dynamic changes in mitochondrial morphology are involved in cellular apoptotic response. However, whether DRP1-mediated mitochondrial fission is required for induction of apoptosis remains speculative. Here, we show that siRNA-mediated DRP1 knockdown promoted accumulation of elongated mitochondria in HCT116 and SW480 human colon cancer cells. Surprisingly, DRP1 down-regulation led to decreased proliferation and increased apoptosis of these cells. A higher rate of cytochrome c release and reductions in mitochondrial membrane potential were also revealed in DRP1-depleted cells. Taken together, our present findings suggest that mitochondrial fission factor DRP1 inhibits colon cancer cell apoptosis through the regulation of cytochrome c release and mitochondrial membrane integrity.

  14. Human Cockayne syndrome B protein reciprocally communicates with mitochondrial proteins and promotes transcriptional elongation

    Science.gov (United States)

    Canugovi, Chandrika; Sykora, Peter; Wilson, David M.; Bohr, Vilhelm A.

    2012-01-01

    Cockayne syndrome (CS) is a rare human disorder characterized by pathologies of premature aging, neurological abnormalities, sensorineural hearing loss and cachectic dwarfism. With recent data identifying CS proteins as physical components of mitochondria, we sought to identify protein partners and roles for Cockayne syndrome group B (CSB) protein in this organelle. CSB was found to physically interact with and modulate the DNA-binding activity of the major mitochondrial nucleoid, DNA replication and transcription protein TFAM. Components of the mitochondrial transcription apparatus (mitochondrial RNA polymerase, transcription factor 2B and TFAM) all functionally interacted with CSB and stimulated its double-stranded DNA-dependent adenosine triphosphatase activity. Moreover, we found that patient-derived CSB-deficient cells exhibited a defect in efficient mitochondrial transcript production and that CSB specifically promoted elongation by the mitochondrial RNA polymerase in vitro. These observations provide strong evidence for the importance of CSB in maintaining mitochondrial function and argue that the pathologies associated with CS are in part, a direct result of the roles that CSB plays in mitochondria. PMID:22743267

  15. Tributyltin induces mitochondrial fission through NAD-IDH dependent mitofusin degradation in human embryonic carcinoma cells.

    Science.gov (United States)

    Yamada, Shigeru; Kotake, Yaichiro; Nakano, Mizuho; Sekino, Yuko; Kanda, Yasunari

    2015-08-01

    Organotin compounds, such as tributyltin (TBT), are well-known endocrine disruptors. TBT acts at the nanomolar level through genomic pathways via the peroxisome proliferator activated receptor (PPAR)/retinoid X receptor (RXR). We recently reported that TBT inhibits cell growth and the ATP content in the human embryonic carcinoma cell line NT2/D1 via a non-genomic pathway involving NAD(+)-dependent isocitrate dehydrogenase (NAD-IDH), which metabolizes isocitrate to α-ketoglutarate. However, the molecular mechanisms by which NAD-IDH mediates TBT toxicity remain unclear. In the present study, we evaluated the effects of TBT on mitochondrial NAD-IDH and energy production. Staining with MitoTracker revealed that nanomolar TBT levels induced mitochondrial fragmentation. TBT also degraded the mitochondrial fusion proteins, mitofusins 1 and 2. Interestingly, apigenin, an inhibitor of NAD-IDH, mimicked the effects of TBT. Incubation with an α-ketoglutarate analogue partially recovered TBT-induced mitochondrial dysfunction, supporting the involvement of NAD-IDH. Our data suggest that nanomolar TBT levels impair mitochondrial quality control via NAD-IDH in NT2/D1 cells. Thus, mitochondrial function in embryonic cells could be used to assess cytotoxicity associated with metal exposure.

  16. Effect of resveratrol on mitochondrial function: Implications in parkin-associated familiar Parkinson's disease

    NARCIS (Netherlands)

    A. Ferretta (Anna); A. Gaballo (Antonio); P. Tanzarella (Paola); C. Piccoli (Claudia); N. Capitanio (Nazzareno); B. Nico (Beatrice); T. Annese (Tiziana); M. Di Paola (Marco); E. Dell'Aquila (Emanuela); M. de Mari; E. Ferranini (Ermanno); V. Bonifati (Vincenzo); C. Pacelli (Consiglia); T. Cocco (Tiziana)

    2014-01-01

    textabstractMitochondrial dysfunction and oxidative stress occur in Parkinson's disease (PD), but the molecular mechanisms controlling these events are not completely understood. Peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) is a transcriptional coactivator known as master

  17. The clinical, biochemical and genetic features associated with RMND1-related mitochondrial disease

    Czech Academy of Sciences Publication Activity Database

    Ng, Y. S.; Alston, Ch. L.; Diodato, D.; Morris, A. A.; Ulrick, N.; Kmoch, S.; Houštěk, Josef; Martinelli, D.; Haghighi, A.; Atiq, M.; Gamero, M. A.; Garcia-Martinez, E.; Kratochvílová, H.; Santra, S.; Brown, R. M.; Brown, G. K.; Ragge, N.; Monavari, A.; Pysden, K.; Ravn, K.; Casey, J. P.; Khan, A.; Chakrapani, A.; Vassallo, G.; Simons, C.; McKeever, K.; O´Sullivan, S.; Childs, A.-M.; Ostergaard, E.; Vanderver, A.; Goldstein, A.; Vogt, J.; Taylor, R. W.; McFarland, R.

    2016-01-01

    Roč. 53, č. 11 (2016), s. 768-775 ISSN 0022-2593 R&D Projects: GA ČR(CZ) GB14-36804G Institutional support: RVO:67985823 Keywords : congenital sensorineural deafness * lactic acidosis * mitochondrial respiratory chain deficiencies * prognosis * renal disease Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.451, year: 2016

  18. Mitochondrial DNA differentiates Alzheimer's disease from Creutzfeldt-Jakob disease.

    Science.gov (United States)

    Podlesniy, Petar; Llorens, Franc; Golanska, Ewa; Sikorska, Beata; Liberski, Pawel; Zerr, Inga; Trullas, Ramon

    2016-05-01

    Low content of cell-free mitochondrial DNA (mtDNA) in cerebrospinal fluid (CSF) is a biomarker of early stage Alzheimer's disease (AD), but whether mtDNA is altered in a rapid neurodegenerative dementia such as Creutzfeldt-Jakob disease is unknown. CSF mtDNA was measured using digital polymerase chain reaction (dPCR) in two independent cohorts comprising a total of 112 patients diagnosed with sporadic Creutzfeldt-Jakob disease (sCJD), probable AD, or non-Alzheimer's type dementia. Patients with AD exhibit low mtDNA content in CSF compared with patients diagnosed with sCJD or with non-Alzheimer's type dementias. The CSF concentration of mtDNA does not correlate with Aβ, t-tau, p-tau, and 14-3-3 protein levels in CSF. Low-CSF mtDNA is not a consequence of brain damage and allows the differential diagnosis of AD from sCJD and other dementias. These results support the hypothesis that mtDNA in CSF is a pathophysiological biomarker of AD. Copyright © 2015 Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. The Human Disease Network

    National Research Council Canada - National Science Library

    Kwang-Il Goh; Michael E. Cusick; David Valle; Barton Childs; Marc Vidal; Albert-László Barabási

    2007-01-01

    A network of disorders and disease genes linked by known disordergene associations offers a platform to explore in a single graphtheoretic framework all known phenotype and disease gene associations...

  1. Interaction of human mitochondrial transcription factor A in mitochondria: its involvement in the dynamics of mitochondrial DNA nucleoids.

    Science.gov (United States)

    Kasashima, Katsumi; Endo, Hitoshi

    2015-12-01

    Mitochondrial transcription factor A (TFAM) is a key regulator of mitochondrial DNA (mtDNA). TFAM interacts with itself and forms dimers; however, the precise interaction domain in vivo has not yet been determined. We herein showed that human TFAM formed oligomers in mitochondria by in situ chemical cross-linking. We used the separated fluorescent protein, monomeric Kusabira-Green, as a reporter to monitor their self-association in mitochondria. This reporter successfully detected the TFAM-TFAM interaction in cells as fluorescent signals on mitochondria. We also found that the N-terminal high-mobility group box domain was sufficient for this interaction. The expression of the dimer-defective mutant induced enlarged mtDNA nucleoids, suggesting the importance of dimerization in the distribution of mtDNA. The reporter system also supported the association and mixture between independent nucleoids through TFAM by a cell fusion assay using hemagglutinating virus of Japan. We here, for the first time, visualized the interaction of TFAM molecules in mitochondria and proposed its implications for the dynamics of mtDNA nucleoids. © 2015 The Molecular Biology Society of Japan and Wiley Publishing Asia Pty Ltd.

  2. Mitochondrial impairment observed in fibroblasts from South African Parkinson’s disease patients with parkin mutations

    Energy Technology Data Exchange (ETDEWEB)

    Merwe, Celia van der, E-mail: celiavdm@sun.ac.za [Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town (South Africa); Loos, Ben [Department of Physiological Sciences, Faculty of Science, Stellenbosch University, Stellenbosch (South Africa); Swart, Chrisna [Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town (South Africa); Kinnear, Craig [Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town (South Africa); MRC Centre for Molecular and Cellular Biology and the DST/NRF Centre of Excellence for Biomedical TB Research, Stellenbosch University, Cape Town (South Africa); Henning, Franclo [Division of Neurology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town (South Africa); Merwe, Lize van der [Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town (South Africa); Department of Statistics, University of the Western Cape, Cape Town (South Africa); Pillay, Komala [National Health Laboratory Services (NHLS) Histopathology Laboratory, Red Cross Children’s Hospital, Cape Town (South Africa); Muller, Nolan [Division of Anatomical Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town (South Africa); Zaharie, Dan [Neuropathology Unit, Division of Anatomical Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town (South Africa); Engelbrecht, Lize [Cell Imaging Unit, Central Analytical Facility, Stellenbosch University, Cape Town (South Africa); Carr, Jonathan [Division of Neurology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town (South Africa); and others

    2014-05-02

    Highlights: • Mitochondrial dysfunction observed in patients with parkin-null mutations. • Mitochondrial ATP levels were decreased. • Electron-dense vacuoles were observed in the patients. • Mitochondria from muscle biopsies appeared within normal limits. • One patient did not show these defects possibly due to compensatory mechanisms. - Abstract: Parkinson’s disease (PD), defined as a neurodegenerative disorder, is characterized by the loss of dopaminergic neurons in the substantia nigra in the midbrain. Loss-of-function mutations in the parkin gene are a major cause of autosomal recessive, early-onset PD. Parkin has been implicated in the maintenance of healthy mitochondria, although previous studies show conflicting findings regarding mitochondrial abnormalities in fibroblasts from patients harboring parkin-null mutations. The aim of the present study was to determine whether South African PD patients with parkin mutations exhibit evidence for mitochondrial dysfunction. Fibroblasts were cultured from skin biopsies obtained from three patients with homozygous parkin-null mutations, two heterozygous mutation carriers and two wild-type controls. Muscle biopsies were obtained from two of the patients. The muscle fibers showed subtle abnormalities such as slightly swollen mitochondria in focal areas of the fibers and some folding of the sarcolemma. Although no differences in the degree of mitochondrial network branching were found in the fibroblasts, ultrastructural abnormalities were observed including the presence of electron-dense vacuoles. Moreover, decreased ATP levels which are consistent with mitochondrial dysfunction were observed in the patients’ fibroblasts compared to controls. Remarkably, these defects did not manifest in one patient, which may be due to possible compensatory mechanisms. These results suggest that parkin-null patients exhibit features of mitochondrial dysfunction. Involvement of mitochondria as a key role player in PD

  3. 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.

  4. 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.

  5. Alzheimer's Proteins, Oxidative Stress, and Mitochondrial Dysfunction Interplay in a Neuronal Model of Alzheimer's Disease

    Directory of Open Access Journals (Sweden)

    Antonella Bobba

    2010-01-01

    Full Text Available In this paper, we discuss the interplay between beta-amyloid (A peptide, Tau fragments, oxidative stress, and mitochondria in the neuronal model of cerebellar granule neurons (CGNs in which the molecular events reminiscent of AD are activated. The identification of the death route and the cause/effect relationships between the events leading to death could be helpful to manage the progression of apoptosis in neurodegeneration and to define antiapoptotic treatments acting on precocious steps of the death process. Mitochondrial dysfunction is among the earliest events linked to AD and might play a causative role in disease onset and progression. Recent studies on CGNs have shown that adenine nucleotide translocator (ANT impairment, due to interaction with toxic N-ter Tau fragment, contributes in a significant manner to bioenergetic failure and mitochondrial dysfunction. These findings open a window for new therapeutic strategies aimed at preserving and/or improving mitochondrial function.

  6. Mitochondrial dysfunction in calf muscles of patients with combined peripheral arterial disease and diabetes type 2

    DEFF Research Database (Denmark)

    Lindegaard Pedersen, Brian; Bækgaard, Niels; Quistorff, Bjørn

    2017-01-01

    BACKGROUND: This study elucidate the effects on muscle mitochondrial function in patients suffering from combined peripheral arterial disease (PAD) and type 2 diabetes (T2D) and the relation to patient symptoms and treatment. METHODS: Near Infra Red Spectroscopy (NIRS) calf muscle exercise tests...... tested applying high resolution oxygraphy on isolated muscle fibers. RESULTS: The NIRS exercise tests showed evidence of mitochondrial dysfunction in the PAD+T2D group by a longer recovery of the deoxygenation resulting from exercise in spite of a higher exercise oxygenation level compared to the PAD...... were conducted on Forty subjects, 15 (PAD), 15 (PAD+T2D) and 10 healthy age matched controls (CTRL) recruited from the vascular outpatient clinic at Gentofte County Hospital, Denmark. Calf muscle biopsies (~ 80 mg) (Gastrocnemius and Anterior tibial muscles) were sampled and mitochondrial function...

  7. Concise Review: Induced Pluripotent Stem Cell-Based Drug Discovery for Mitochondrial Disease.

    Science.gov (United States)

    Inak, Gizem; Lorenz, Carmen; Lisowski, Pawel; Zink, Annika; Mlody, Barbara; Prigione, Alessandro

    2017-07-01

    High attrition rates and loss of capital plague the drug discovery process. This is particularly evident for mitochondrial disease that typically involves neurological manifestations and is caused by nuclear or mitochondrial DNA defects. This group of heterogeneous disorders is difficult to target because of the variability of the symptoms among individual patients and the lack of viable modeling systems. The use of induced pluripotent stem cells (iPSCs) might significantly improve the search for effective therapies for mitochondrial disease. iPSCs can be used to generate patient-specific neural cell models in which innovative compounds can be identified or validated. Here we discuss the promises and challenges of iPSC-based drug discovery for mitochondrial disease with a specific focus on neurological conditions. We anticipate that a proper use of the potent iPSC technology will provide critical support for the development of innovative therapies against these untreatable and detrimental disorders. Stem Cells 2017;35:1655-1662. © 2017 AlphaMed Press.

  8. Molecular pathophysiology of impaired glucose metabolism, mitochondrial dysfunction, and oxidative DNA damage in Alzheimer's disease brain.

    Science.gov (United States)

    Abolhassani, Nona; Leon, Julio; Sheng, Zijing; Oka, Sugako; Hamasaki, Hideomi; Iwaki, Toru; Nakabeppu, Yusaku

    2017-01-01

    In normal brain, neurons in the cortex and hippocampus produce insulin, which modulates glucose metabolism and cognitive functions. It has been shown that insulin resistance impairs glucose metabolism and mitochondrial function, thus increasing production of reactive oxygen species. Recent progress in Alzheimer's disease (AD) research revealed that insulin production and signaling are severely impaired in AD brain, thereby resulting in mitochondrial dysfunction and increased oxidative stress. Among possible oxidative DNA lesions, 8-oxoguanine (8-oxoG) is highly accumulated in the brain of AD patients. Previously we have shown that incorporating 8-oxoG in nuclear and mitochondrial DNA promotes MUTYH (adenine DNA glycosylase) dependent neurodegeneration. Moreover, cortical neurons prepared from MTH1 (8-oxo-dGTPase)/OGG1 (8-oxoG DNA glycosylase)-double deficient adult mouse brains is shown to exhibit significantly poor neuritogenesis in vitro with increased 8-oxoG accumulation in mitochondrial DNA in the absence of antioxidants. Therefore, 8-oxoG can be considered involved in the neurodegenerative process in AD brain. In mild cognitive impairment, mitochondrial dysfunction and oxidative damage may induce synaptic dysfunction due to energy failures in neurons thus resulting in impaired cognitive function. If such abnormality lasts long, it can lead to vicious cycles of oxidative damage, which may then trigger the neurodegenerative process seen in Alzheimer type dementia. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Mitochondrial Genome Encoded Proteins Expression Disorder, the Possible Mechanism of the Heart Disease in Metabolic Syndrome

    Directory of Open Access Journals (Sweden)

    Ningning Zheng

    2017-09-01

    Full Text Available Background/Aims: The direct consequence of metabolic syndrome (MS is the increased morbidity and mortality caused by the heart disease. We tried to explain why the heart is more severely damaged during MS from the point of mitochondria, the center of cellular metabolism. Methods: 1. The classic diet induced MS rat model was used to observe the morphological changes of mitochondria by transmission electron microscope (TEM; 2. The expression of mitochondrial DNA (mt-DNA encoded proteins was observed by immunohistochemistry and Western blot; 3. The expression of mitochondrial ribosomal proteins (MRPs was observed by real-time PCR. Results: 1. The mitochondrial volume increased but the number was normal in myocardial cells of the MS rats. But in the hepatocytes and skeletal muscle cells, the mitochondrial number decreased; 2.The mt-DNA encoded protein cytochrome b increased significantly in heart but decreased in liver and the ATPase6 increased in liver but decreased in heart of the MS rats; 3. The mRNA levels of MRPS23, MRPL27, MRPL45 and MRPL48 elevated in heart but down-regulated in liver of the MS rats. Conclusion: The morphologic and functional alterations of mitochondrion in MS were tissue specific. Heart displays a distinctive pattern of mitochondrial metabolic status compared with other tissues.

  10. Maternal age effect and severe germ-line bottleneck in the inheritance of human mitochondrial DNA

    DEFF Research Database (Denmark)

    Rebolledo-Jaramillo, Boris; Su, Marcia Shu-Wei; Stoler, Nicholas

    2014-01-01

    The manifestation of mitochondrial DNA (mtDNA) diseases depends on the frequency of heteroplasmy (the presence of several alleles in an individual), yet its transmission across generations cannot be readily predicted owing to a lack of data on the size of the mtDNA bottleneck during oogenesis...

  11. Evolutionary defined role of the mitochondrial DNA in fertility, disease and ageing.

    Science.gov (United States)

    Otten, Auke B C; Smeets, Hubert J M

    2015-01-01

    The endosymbiosis of an alpha-proteobacterium and a eubacterium a billion years ago paved the way for multicellularity and enabled eukaryotes to flourish. The selective advantage for the host was the acquired ability to generate large amounts of intracellular hydrogen-dependent adenosine triphosphate. The price was increased reactive oxygen species (ROS) inside the eukaryotic cell, causing high mutation rates of the mitochondrial DNA (mtDNA). According to the Muller's ratchet theory, this accumulation of mutations in asexually transmitted mtDNA would ultimately lead to reduced reproductive fitness and eventually extinction. However, mitochondria have persisted over the course of evolution, initially due to a rapid, extreme evolutionary reduction of the mtDNA content. After the phylogenetic divergence of eukaryotes into animals, fungi and plants, differences in evolution of the mtDNA occurred with different adaptations for coping with the mutation burden within these clades. As a result, mitochondrial evolutionary mechanisms have had a profound effect on human adaptation, fertility, healthy reproduction, mtDNA disease manifestation and transmission and ageing. An understanding of these mechanisms might elucidate novel approaches for treatment and prevention of mtDNA disease. The scientific literature was investigated to determine how mtDNA evolved in animals, plants and fungi. Furthermore, the different mechanisms of mtDNA inheritance and of balancing Muller's ratchet in these species were summarized together with the consequences of these mechanisms for human health and reproduction. Animal, plant and fungal mtDNA have evolved differently. Animals have compact genomes, little recombination, a stable number of genes and a high mtDNA copy number, whereas plants have larger genomes with variable gene counts, a low mtDNA copy number and many recombination events. Fungal mtDNA is somewhere in between. In plants, the mtDNA mutation rate is kept low by effective ROS

  12. Changes in mitochondrial stability during the progression of the Barrett's esophagus disease sequence.

    Science.gov (United States)

    O'Farrell, N J; Feighery, R; Picardo, S L; Lynam-Lennon, N; Biniecka, M; McGarrigle, S A; Phelan, J J; MacCarthy, F; O'Toole, D; Fox, E J; Ravi, N; Reynolds, J V; O'Sullivan, J

    2016-07-19

    Barrett's esophagus follows the classic step-wise progression of metaplasia-dysplasia-adenocarcinoma. While Barrett's esophagus is a leading known risk factor for esophageal adenocarcinoma, the pathogenesis of this disease sequence is poorly understood. Mitochondria are highly susceptible to mutations due to high levels of reactive oxygen species (ROS) coupled with low levels of DNA repair. The timing and levels of mitochondria instability and dysfunction across the Barrett's disease progression is under studied. Using an in-vitro model representing the Barrett's esophagus disease sequence of normal squamous epithelium (HET1A), metaplasia (QH), dysplasia (Go), and esophageal adenocarcinoma (OE33), random mitochondrial mutations, deletions and surrogate markers of mitochondrial function were assessed. In-vivo and ex-vivo tissues were also assessed for instability profiles. Barrett's metaplastic cells demonstrated increased levels of ROS (p disease sequence in-vitro. Using patient in-vivo samples, Barrett's metaplasia tissue demonstrated significantly increased levels of random mitochondrial deletions (p = 0.043) compared with esophageal adenocarcinoma tissue, along with increased expression of cytoglobin (CYGB) (p disease sequence. Using ex-vivo Barrett's metaplastic and matched normal patient tissue explants, higher levels of cytochrome c (p = 0.003), SMAC/Diablo (p = 0.008) and four inflammatory cytokines (all p values disease sequence.

  13. Transcutaneous application of carbon dioxide (CO2 induces mitochondrial apoptosis in human malignant fibrous histiocytoma in vivo.

    Directory of Open Access Journals (Sweden)

    Yasuo Onishi

    Full Text Available Mitochondria play an essential role in cellular energy metabolism and apoptosis. Previous studies have demonstrated that decreased mitochondrial biogenesis is associated with cancer progression. In mitochondrial biogenesis, peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α regulates the activities of multiple nuclear receptors and transcription factors involved in mitochondrial proliferation. Previously, we showed that overexpression of PGC-1α leads to mitochondrial proliferation and induces apoptosis in human malignant fibrous histiocytoma (MFH cells in vitro. We also demonstrated that transcutaneous application of carbon dioxide (CO(2 to rat skeletal muscle induces PGC-1α expression and causes an increase in mitochondrial proliferation. In this study, we utilized a murine model of human MFH to determine the effect of transcutaneous CO(2 exposure on PGC-1α expression, mitochondrial proliferation and cellular apoptosis. PGC-1α expression was evaluated by quantitative real-time PCR, while mitochondrial proliferation was assessed by immunofluorescence staining and the relative copy number of mitochondrial DNA (mtDNA was assessed by real-time PCR. Immunofluorescence staining and DNA fragmentation assays were used to examine mitochondrial apoptosis. We also evaluated the expression of mitochondrial apoptosis related proteins, such as caspases, cytochorome c and Bax, by immunoblot analysis. We show that transcutaneous application of CO(2 induces PGC-1α expression, and increases mitochondrial proliferation and apoptosis of tumor cells, significantly reducing tumor volume. Proteins involved in the mitochondrial apoptotic cascade, including caspase 3 and caspase 9, were elevated in CO(2 treated tumors compared to control. We also observed an enrichment of cytochrome c in the cytoplasmic fraction and Bax protein in the mitochondrial fraction of CO(2 treated tumors, highlighting the involvement of mitochondria in apoptosis

  14. Radiation response of chemically derived mitochondrial DNA-deficient AG01522 human primary fibroblasts.

    Science.gov (United States)

    Nieri, D; Fioramonti, M; Berardinelli, F; Leone, S; Cherubini, R; De Nadal, V; Gerardi, S; Moreno, S; Nardacci, R; Tanzarella, C; Antoccia, A

    2013-08-30

    Mitochondria are the main cellular source of Reactive Oxygen Species (ROS). Alterations of mitochondrial metabolism and consequent loss of mitochondrial membrane potential may lead to redox imbalance and in turn to DNA damage, chromosomal instability and apoptosis. On the other hand, impaired mitochondrial functions may either exacerbate the detrimental effects of geno- and cytotoxic agents or may bring beneficial cellular responses. To study the role of mitochondria within this framework, AG01522 human primary fibroblasts were incubated with the mitochondrial polymerase γ inhibitor 2',3'-dideoxycytidine (ddC), leading to mitochondrial DNA (mtDNA) depletion and to mitochondrial dysfunctions. The successful treatment toward mtDNA depletion was confirmed by Complex-IV subunit I (COX-I) immunofluorescence and western blot assays. mtDNA-depleted cells and their counterparts were ultrastructurally characterized by transmission electron microscopy. mtDNA-depleted cells showed dramatic mitochondrial alterations such as fragmentation and cristae disruption along with a reduction of the mitochondrial membrane potential and elevated levels of ROS. Despite increased ROS levels, we did not find any difference in telomere length between ddC-treated and untreated cells. The spontaneous rate of DNA double-strand breaks (DSBs) and chromosome aberrations was significantly enhanced in mtDNA-depleted cells whereas the induction of DSBs by low-Linear Energy Transfer (LET) (X-rays; 7.7keV/μm protons) and high-LET radiations (28.5keV/μm protons) did not differ when compared with normal cells. However, in irradiated cells impaired mitochondrial functions seemed to bring beneficial cellular responses to the detrimental effect of radiations. In fact, after X-irradiation mtDNA-depleted cells show less remaining unrejoined DSBs than normal cells and furthermore a lower induction of cytogenetic damage. Overall, these data show that active mitochondrial functions are required for the proper

  15. Mitochondrial diseases in children: neuroradiological and clinical features in 17 patients

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, A. [Neuroradiologia Pediatrica, Servicio de Radiodiagnostico, Hospital Universitario, Madrid (Spain); Mateos, F.; Simon, R. [Neurologia Pediatrica, Servicio de Radiodiagnostico, Hospital Univ. Madrid (Spain); Garcia-Silva, M.T. [Unidad de Enfermedades Mitocondriales, Departamento de Pediatria, Hospital Universitario 12 de Octubre, Ctra. Andalucia, Km. 5400, E-28041 Madrid (Spain); Cabello, S. [Neuropatologia, Departamento de Anatomia Patologica, Hospital Universitario 12 de Octubre, Ctra. Andalucia, Km. 5400, E-28041 Madrid (Spain); Arenas, J. [Servicio de Bioquimica, Hospital Universitario 12 de Octubre, Ctra. Andalucia, Km. 5400, E-28041 Madrid (Spain)

    1999-12-01

    Mitochondrial diseases result from structural, biochemical or genetic defects of mitochondria, which contain the respiratory chain. They usually affect children and young adults. We report the CT and MRI findings in 17 patients under 14 years of age, the youngest reported to date, with various mitochondrial diseases. Although imaging studies may be normal negative in the early stages, follow-up usually shows many abnormalities, which depend on clinical status and the disease. We have recognised a spectrum of findings that can be divided into four patterns: nonspecific myelin lesions (8/17); grey-matter nuclei involvement (6/17); a leukodystrophic pattern; and calcification of the brain (1/17), although mixed forms, particularly myelin and grey-matter lesions are frequent. (orig.)

  16. Mitochondrial Dysfunction in Neocortex and Hippocampus of Olfactory Bulbectomized Mice, a Model of Alzheimer's Disease.

    Science.gov (United States)

    Avetisyan, A V; Samokhin, A N; Alexandrova, I Y; Zinovkin, R A; Simonyan, R A; Bobkova, N V

    2016-06-01

    Structural and functional impairments of mitochondria in brain tissues in the pathogenesis of Alzheimer's disease (AD) cause energy deficiency, increased generation of reactive oxygen species (ROS), and premature neuronal death. However, the causal relations between accumulation of beta-amyloid (Aβ) peptide in mitochondria and mitochondrial dysfunction, as well as molecular mechanisms underlying deleterious effects of both these factors in sporadic AD, the most common form in humans, remain unknown. Here we used olfactory bulbectomized (OBX) mice of NMRI strain as a model for sporadic AD. Five weeks after surgery, the OBX mice developed major behavioral and biochemical features of AD neurodegeneration, including spatial memory loss, increased brain levels of Aβ, and energy deficiency. Mitochondria isolated from the neocortex and hippocampus of OBX mice displayed severe functional impairments, such as low NADH oxidation rate, reduced transmembrane potential, and decreased cytochrome c oxidase (complex IV) activity that correlated with high levels of soluble Aβ1-40. Mitochondria from OBX mice showed increased contents of lipid peroxidation products, indicative of the development of oxidative stress. We found that neurodegeneration caused by olfactory bulbectomy is accompanied by energy metabolism disturbances and oxidative stress in brain mitochondria similar to those occurring in transgenic animals - familial AD models and patients with sporadic AD. Therefore, OBX mice can serve as a valid AD model for investigating the mechanisms of AD neurodegeneration, drug testing, and development of therapeutic strategies for AD treatment.

  17. Mitochondrial dynamics, quality control and miRNA regulation in skeletal muscle: implications for obesity and related metabolic disease.

    Science.gov (United States)

    Dahlmans, Dennis; Houzelle, Alexandre; Schrauwen, Patrick; Hoeks, Joris

    2016-06-01

    The western dietary habits and sedentary lifestyle largely contributes to the growing epidemic of obesity. Mitochondria are at the front line of cellular energy homoeostasis and are implicated in the pathophysiology of obesity and obesity-related metabolic disease. In recent years, novel aspects in the regulation of mitochondrial metabolism, such as mitochondrial dynamics, mitochondrial protein quality control and post-transcriptional regulation of genes coding for mitochondrial proteins, have emerged. In this review, we discuss the recent findings concerning the dysregulation of these processes in skeletal muscle in obesogenic conditions. © 2016 Authors; published by Portland Press Limited.

  18. Mitochondrial BAX Determines the Predisposition to Apoptosis in Human AML.

    Science.gov (United States)

    Reichenbach, Frank; Wiedenmann, Cornelius; Schalk, Enrico; Becker, Diana; Funk, Kathrin; Scholz-Kreisel, Peter; Todt, Franziska; Wolleschak, Denise; Döhner, Konstanze; Marquardt, Jens U; Heidel, Florian; Edlich, Frank

    2017-08-15

    Purpose: Cell-to-cell variability in apoptosis signaling contributes to heterogenic responses to cytotoxic stress in clinically heterogeneous neoplasia, such as acute myeloid leukemia (AML). The BCL-2 proteins BAX and BAK can commit mammalian cells to apoptosis and are inhibited by retrotranslocation from the mitochondria into the cytosol. The subcellular localization of BAX and BAK could determine the cellular predisposition to apoptotic death.Experimental Design: The relative localization of BAX and BAK was determined by fractionation of AML cell lines and patient samples of a test cohort and a validation cohort.Results: This study shows that relative BAX localization determines the predisposition of different AML cell lines to apoptosis. Human AML displays a surprising variety of relative BAX localizations. In a test cohort of 48 patients with AML, mitochondria-shifted BAX correlated with improved patient survival, FLT3-ITD status, and leukocytosis. Analysis of a validation cohort of 80 elderly patients treated with myelosuppressive chemotherapy confirmed that relative BAX localization correlates with probability of disease progression, FLT3-ITD status, and leukocytosis. Relative BAX localization could therefore be helpful to identify elderly or frail patients who may benefit from cytotoxic therapy.Conclusions: In this retrospective analysis of two independent AML cohorts, our data suggest that Bax localization may predict prognosis of patients with AML and cellular predisposition to apoptosis, combining the actual contribution of known and unknown factors to a final "common path." Clin Cancer Res; 23(16); 4805-16. ©2017 AACR. ©2017 American Association for Cancer Research.

  19. Characterization of human GTPBP3, a GTP-binding protein involved in mitochondrial tRNA modification.

    Science.gov (United States)

    Villarroya, Magda; Prado, Silvia; Esteve, Juan M; Soriano, Miguel A; Aguado, Carmen; Pérez-Martínez, David; Martínez-Ferrandis, José I; Yim, Lucía; Victor, Victor M; Cebolla, Elvira; Montaner, Asunción; Knecht, Erwin; Armengod, M-Eugenia

    2008-12-01

    Human GTPBP3 is an evolutionarily conserved, multidomain protein involved in mitochondrial tRNA modification. Characterization of its biochemical properties and the phenotype conferred by GTPBP3 inactivation is crucial to understanding the role of this protein in tRNA maturation and its effects on mitochondrial respiration. We show that the two most abundant GTPBP3 isoforms exhibit moderate affinity for guanine nucleotides like their bacterial homologue, MnmE, although they hydrolyze GTP at a 100-fold lower rate. This suggests that regulation of the GTPase activity, essential for the tRNA modification function of MnmE, is different in GTPBP3. In fact, potassium-induced dimerization of the G domain leads to stimulation of the GTPase activity in MnmE but not in GTPBP3. The GTPBP3 N-terminal domain mediates a potassium-independent dimerization, which appears as an evolutionarily conserved property of the protein family, probably related to the construction of the binding site for the one-carbon-unit donor in the modification reaction. Partial inactivation of GTPBP3 by small interfering RNA reduces oxygen consumption, ATP production, and mitochondrial protein synthesis, while the degradation of these proteins slightly increases. It also results in mitochondria with defective membrane potential and increased superoxide levels. These phenotypic traits suggest that GTPBP3 defects contribute to the pathogenesis of some oxidative phosphorylation diseases.

  20. 2-ethylpyridine, a cigarette smoke component, causes mitochondrial damage in human retinal pigment epithelial cells in vitro

    Directory of Open Access Journals (Sweden)

    S Mansoor

    2014-01-01

    Full Text Available Purpose: Our goal was to identify the cellular and molecular effects of 2-ethylpyridine (2-EP, a component of cigarette smoke on human retinal pigment epithelial cells (ARPE-19 in vitro. Materials and Methods: ARPE-19 cells were exposed to varying concentrations of 2-EP. Cell viability (CV was measured by a trypan blue dye exclusion assay. Caspase-3/7 and caspase-9 activities were measured by fluorochrome assays. The production of reactive oxygen/nitrogen species (ROS/RNS was detected with a 2′,7′-dichlorodihydrofluorescein diacetate dye assay. The JC-1 assay was used to measure mitochondrial membrane potential (ΔΨm. Mitochondrial redox potential was measured using a RedoxSensor Red kit and mitochondria were evaluated with Mitotracker dye. Results: After 2-EP exposure, ARPE-19 cells showed significantly decreased CV, increased caspase-3/7 and caspase-9 activities, elevated ROS/RNS levels, decreased ΔΨm value and decreased redox fluorescence when compared with control samples. Conclusions: These results show that 2-EP treatment induced cell death by caspase-dependent apoptosis associated with an oxidative stress and mitochondrial dysfunction. These data represent a possible mechanism by which smoking contributes to age-related macular degeneration and other retinal diseases and identify mitochondria as a target for future therapeutic interventions.

  1. Extra-ocular muscle MRI in genetically-defined mitochondrial disease.

    Science.gov (United States)

    Pitceathly, Robert D S; Morrow, Jasper M; Sinclair, Christopher D J; Woodward, Cathy; Sweeney, Mary G; Rahman, Shamima; Plant, Gordon T; Ali, Nadeem; Bremner, Fion; Davagnanam, Indran; Yousry, Tarek A; Hanna, Michael G; Thornton, John S

    2016-01-01

    Conventional and quantitative MRI was performed in patients with chronic progressive external ophthalmoplegia (CPEO), a common manifestation of mitochondrial disease, to characterise MRI findings in the extra-ocular muscles (EOMs) and investigate whether quantitative MRI provides clinically relevant measures of disease. Patients with CPEO due to single mitochondrial DNA deletions were compared with controls. Range of eye movement (ROEM) measurements, peri-orbital 3 T MRI T1-weighted (T1w) and short-tau-inversion-recovery (STIR) images, and T2 relaxation time maps were obtained. Blinded observers graded muscle atrophy and T1w/STIR hyperintensity. Cross-sectional areas and EOM mean T2s were recorded and correlated with clinical parameters. Nine patients and nine healthy controls were examined. Patients had reduced ROEM (patients 13.3°, controls 49.3°, p CPEO. Correlation between elevated EOM T2 and ROEM impairment represents a potential measure of disease severity that warrants further evaluation. Chronic progressive external ophthalmoplegia is a common clinical manifestation of mitochondrial disease. • Existing extra-ocular muscle MRI data in CPEO reports variable radiological findings. MRI confirmed EOM atrophy and characteristic signal changes in CPEO. EOM T2 was significantly elevated in CPEO and correlated negatively with ocular movements. EOM T2 represents a potential quantitative measure of disease severity in CPEO.

  2. Fetal programming of chronic kidney disease: the role of maternal smoking, mitochondrial dysfunction, and epigenetic modfification.

    Science.gov (United States)

    Stangenberg, Stephanie; Chen, Hui; Wong, Muh Geot; Pollock, Carol A; Saad, Sonia

    2015-06-01

    The role of an adverse in utero environment in the programming of chronic kidney disease in the adult offspring is increasingly recognized. The cellular and molecular mechanisms linking the in utero environment and future disease susceptibility remain unknown. Maternal smoking is a common modifiable adverse in utero exposure, potentially associated with both mitochondrial dysfunction and epigenetic modification in the offspring. While studies are emerging that point toward a key role of mitochondrial dysfunction in acute and chronic kidney disease, it may have its origin in early development, becoming clinically apparent when secondary insults occur. Aberrant epigenetic programming may add an additional layer of complexity to orchestrate fibrogenesis in the kidney and susceptibility to chronic kidney disease in later life. In this review, we explore the evidence for mitochondrial dysfunction and epigenetic modification through aberrant DNA methylation as key mechanistic aspects of fetal programming of chronic kidney disease and discuss their potential use in diagnostics and targets for therapy. Copyright © 2015 the American Physiological Society.

  3. Amplifying mitochondrial function rescues adult neurogenesis in a mouse model of Alzheimer's disease.

    Science.gov (United States)

    Richetin, Kevin; Moulis, Manon; Millet, Aurélie; Arràzola, Macarena S; Andraini, Trinovita; Hua, Jennifer; Davezac, Noélie; Roybon, Laurent; Belenguer, Pascale; Miquel, Marie-Christine; Rampon, Claire

    2017-06-01

    Adult hippocampal neurogenesis is strongly impaired in Alzheimer's disease (AD). In several mouse models of AD, it was shown that adult-born neurons exhibit reduced survival and altered synaptic integration due to a severe lack of dendritic spines. In the present work, using the APPxPS1 mouse model of AD, we reveal that this reduced number of spines is concomitant of a marked deficit in their neuronal mitochondrial content. Remarkably, we show that targeting the overexpression of the pro-neural transcription factor Neurod1 into APPxPS1 adult-born neurons restores not only their dendritic spine density, but also their mitochondrial content and the proportion of spines associated with mitochondria. Using primary neurons, a bona fide model of neuronal maturation, we identified that increases of mitochondrial respiration accompany the stimulating effect of Neurod1 overexpression on dendritic growth and spine formation. Reciprocally, pharmacologically impairing mitochondria prevented Neurod1-dependent trophic effects. Thus, since overexpression of Neurod1 into new neurons of APPxPS1 mice rescues spatial memory, our present data suggest that manipulating the mitochondrial system of adult-born hippocampal neurons provides neuronal plasticity to the AD brain. These findings open new avenues for far-reaching therapeutic implications towards neurodegenerative diseases associated with cognitive impairment. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Lactate dehydrogenase is not a mitochondrial enzyme in human and mouse vastus lateralis muscle

    DEFF Research Database (Denmark)

    Rasmussen, Hans N; van Hall, Gerrit; Rasmussen, Ulla F

    2002-01-01

    The presence of lactate dehydrogenase in skeletal muscle mitochondria was investigated to clarify whether lactate is a possible substrate for mitochondrial respiration. Mitochondria were prepared from 100 mg samples of human and mouse vastus lateralis muscle. All fractions from the preparation...... procedure were assayed for marker enzymes and lactate dehydrogenase (LDH). The mitochondrial fraction contained no LDH activity (detection limit approximately 0.05 % of the tissue activity) and the distribution of LDH activity among the fractions paralleled that of pyruvate kinase, i.e. LDH was fractionated...... as a cytoplasmic enzyme. Respiratory experiments with the mitochondrial fraction also indicated the absence of LDH. Lactate did not cause respiration, nor did it affect the respiration of pyruvate + malate. The major part of the native cytochrome c was retained in the isolated mitochondria, which, furthermore...

  5. Insulin resistance and the mitochondrial link. Lessons from cultured human myotubes

    DEFF Research Database (Denmark)

    Gaster, Michael

    2007-01-01

    In order to better understand the impact of reduced mitochondrial function for the development of insulin resistance and cellular metabolism, human myotubes were established from lean, obese, and T2D subjects and exposed to mitochondrial inhibitors, either affecting the electron transport chain...... lipid uptake. The metabolic phenotype during respiratory uncoupling resembled the above picture, except for an increase in glucose and palmitate oxidation. Antimycin A and oligomycin treatment induced insulin resistance at the level of glucose and palmitate uptake in all three study groups while......, at the level of glycogen synthesis, insulin resistance was only seen in lean myotubes. Primary insulin resistance in diabetic myotubes was significantly worsened at the level of glucose and lipid uptake. The present study is the first convincing data linking functional mitochondrial impairment per se...

  6. Characterization of Human and Yeast Mitochondrial Glycine Carriers with Implications for Heme Biosynthesis and Anemia.

    Science.gov (United States)

    Lunetti, Paola; Damiano, Fabrizio; De Benedetto, Giuseppe; Siculella, Luisa; Pennetta, Antonio; Muto, Luigina; Paradies, Eleonora; Marobbio, Carlo Marya Thomas; Dolce, Vincenza; Capobianco, Loredana

    2016-09-16

    Heme is an essential molecule in many biological processes, such as transport and storage of oxygen and electron transfer as well as a structural component of hemoproteins. Defects of heme biosynthesis in developing erythroblasts have profound medical implications, as represented by sideroblastic anemia. The synthesis of heme requires the uptake of glycine into the mitochondrial matrix where glycine is condensed with succinyl coenzyme A to yield δ-aminolevulinic acid. Herein we describe the biochemical and molecular characterization of yeast Hem25p and human SLC25A38, providing evidence that they are mitochondrial carriers for glycine. In particular, the hem25Δ mutant manifests a defect in the biosynthesis of δ-aminolevulinic acid and displays reduced levels of downstream heme and mitochondrial cytochromes. The observed defects are rescued by complementation with yeast HEM25 or human SLC25A38 genes. Our results identify new proteins in the heme biosynthetic pathway and demonstrate that Hem25p and its human orthologue SLC25A38 are the main mitochondrial glycine transporters required for heme synthesis, providing definitive evidence of their previously proposed glycine transport function. Furthermore, our work may suggest new therapeutic approaches for the treatment of congenital sideroblastic anemia. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Human REV3 DNA Polymerase Zeta Localizes to Mitochondria and Protects the Mitochondrial Genome.

    Science.gov (United States)

    Singh, Bhupendra; Li, Xiurong; Owens, Kjerstin M; Vanniarajan, Ayyasamy; Liang, Ping; Singh, Keshav K

    2015-01-01

    To date, mitochondrial DNA polymerase γ (POLG) is the only polymerase known to be present in mammalian mitochondria. A dogma in the mitochondria field is that there is no other polymerase present in the mitochondria of mammalian cells. Here we demonstrate localization of REV3 DNA polymerase in the mammalian mitochondria. We demonstrate localization of REV3 in the mitochondria of mammalian tissue as well as cell lines. REV3 associates with POLG and mitochondrial DNA and protects the mitochondrial genome from DNA damage. Inactivation of Rev3 leads to reduced mitochondrial membrane potential, reduced OXPHOS activity, and increased glucose consumption. Conversely, inhibition of the OXPHOS increases expression of Rev3. Rev3 expression is increased in human primary breast tumors and breast cancer cell lines. Inactivation of Rev3 decreases cell migration and invasion, and localization of Rev3 in mitochondria increases survival and the invasive potential of cancer cells. Taken together, we demonstrate that REV3 functions in mammalian mitochondria and that mitochondrial REV3 is associated with the tumorigenic potential of cells.

  8. Mitochondrial EFTs defects in juvenile-onset Leigh disease, ataxia, neuropathy, and optic atrophy.

    Science.gov (United States)

    Ahola, Sofia; Isohanni, Pirjo; Euro, Liliya; Brilhante, Virginia; Palotie, Aarno; Pihko, Helena; Lönnqvist, Tuula; Lehtonen, Tanita; Laine, Jukka; Tyynismaa, Henna; Suomalainen, Anu

    2014-08-19

    We report novel defects of mitochondrial translation elongation factor Ts (EFTs), with high carrier frequency in Finland and expand the manifestations of this disease group from infantile cardiomyopathy to juvenile neuropathy/encephalopathy disorders. DNA analysis, whole-exome analysis, protein biochemistry, and protein modeling. We used whole-exome sequencing to find the genetic cause of infantile-onset mitochondrial cardiomyopathy, progressing to juvenile-onset Leigh syndrome, neuropathy, and optic atrophy in 2 siblings. We found novel compound heterozygous mutations, c.944G>A [p.C315Y] and c.856C>T [p.Q286X], in the TSFM gene encoding mitochondrial EFTs. The same p.Q286X variant was found as compound heterozygous with a splice site change in a patient from a second family, with juvenile-onset optic atrophy, peripheral neuropathy, and ataxia. Our molecular modeling predicted the coding-region mutations to cause protein instability, which was experimentally confirmed in cultured patient cells, with mitochondrial translation defect and lacking EFTs. Only a single TSFM mutation has been previously described in different populations, leading to an infantile fatal multisystem disorder with cardiomyopathy. Sequence data from 35,000 Finnish population controls indicated that the heterozygous carrier frequency of p.Q286X change was exceptionally high in Finland, 1:80, but no homozygotes were found in the population, in our mitochondrial disease patient collection, or in an intrauterine fetal death material, suggesting early developmental lethality of the homozygotes. We show that in addition to early-onset cardiomyopathy, TSFM mutations should be considered in childhood and juvenile encephalopathies with optic and/or peripheral neuropathy, ataxia, or Leigh disease. © 2014 American Academy of Neurology.

  9. Data for whole and mitochondrial proteome of human embryonic stem cells

    Directory of Open Access Journals (Sweden)

    Faezeh Shekari

    2017-08-01

    Full Text Available The data presented here pertain to the research article entitled “Proteome Analysis of Human Embryonic Stem Cell Organelles” (Shekariet al., 2017 [1]. In the present article we endeavour to locate new proteins and pathways in human embryonic stem cells (hESCs by mass spectrometry and bioinformatics analysis. We have analyzed total and mitochondrial proteins extracted from three biological replicates of the hESC H9 cell line according to mass spectrometry proteomics and bioinformatics investigations.

  10. Mitochondrial protein quality control: the mechanisms guarding mitochondrial health.

    Science.gov (United States)

    Bohovych, Iryna; Chan, Sherine S L; Khalimonchuk, Oleh

    2015-04-20

    Mitochondria are complex dynamic organelles pivotal for cellular physiology and human health. Failure to maintain mitochondrial health leads to numerous maladies that include late-onset neurodegenerative diseases and cardiovascular disorders. Furthermore, a decline in mitochondrial health is prevalent with aging. A set of evolutionary conserved mechanisms known as mitochondrial quality control (MQC) is involved in recognition and correction of the mitochondrial proteome. Here, we review current knowledge and latest developments in MQC. We particularly focus on the proteolytic aspect of MQC and its impact on health and aging. While our knowledge about MQC is steadily growing, critical gaps remain in the mechanistic understanding of how MQC modules sense damage and preserve mitochondrial welfare, particularly in higher organisms. Delineating how coordinated action of the MQC modules orchestrates physiological responses on both organellar and cellular levels will further elucidate the current picture of MQC's role and function in health, cellular stress, and degenerative diseases.

  11. Eliciting the mitochondrial unfolded protein response by nicotinamide adenine dinucleotide repletion reverses fatty liver disease in mice.

    Science.gov (United States)

    Gariani, Karim; Menzies, Keir J; Ryu, Dongryeol; Wegner, Casey J; Wang, Xu; Ropelle, Eduardo R; Moullan, Norman; Zhang, Hongbo; Perino, Alessia; Lemos, Vera; Kim, Bohkyung; Park, Young-Ki; Piersigilli, Alessandra; Pham, Tho X; Yang, Yue; Ku, Chai Siah; Koo, Sung I; Fomitchova, Anna; Cantó, Carlos; Schoonjans, Kristina; Sauve, Anthony A; Lee, Ji-Young; Auwerx, Johan

    2016-04-01

    With no approved pharmacological treatment, nonalcoholic fatty liver disease (NAFLD) is now the most common cause of chronic liver disease in Western countries and its worldwide prevalence continues to increase along with the growing obesity epidemic. Here, we show that a high-fat high-sucrose (HFHS) diet, eliciting chronic hepatosteatosis resembling human fatty liver, lowers hepatic nicotinamide adenine dinucleotide (NAD(+) ) levels driving reductions in hepatic mitochondrial content, function, and adenosine triphosphate (ATP) levels, in conjunction with robust increases in hepatic weight, lipid content, and peroxidation in C57BL/6J mice. To assess the effect of NAD(+) repletion on the development of steatosis in mice, nicotinamide riboside, a precursor of NAD(+) biosynthesis, was added to the HFHS diet, either as a preventive strategy or as a therapeutic intervention. We demonstrate that NR prevents and reverts NAFLD by inducing a sirtuin (SIRT)1- and SIRT3-dependent mitochondrial unfolded protein response, triggering an adaptive mitohormetic pathway to increase hepatic β-oxidation and mitochondrial complex content and activity. The cell-autonomous beneficial component of NR treatment was revealed in liver-specific Sirt1 knockout mice (Sirt1(hep-/-) ), whereas apolipoprotein E-deficient mice (Apoe(-/-) ) challenged with a high-fat high-cholesterol diet affirmed the use of NR in other independent models of NAFLD. Our data warrant the future evaluation of NAD(+) boosting strategies to manage the development or progression of NAFLD. © 2015 The Authors. Hepatology published by Wiley Periodicals, Inc., on behalf of the American Association for the Study of Liver Diseases.

  12. Synergistic Effects of the in cis T251I and P587L Mitochondrial DNA Polymerase γ Disease Mutations.

    Science.gov (United States)

    DeBalsi, Karen L; Longley, Matthew J; Hoff, Kirsten E; Copeland, William C

    2017-03-10

    Human mitochondrial DNA (mtDNA) polymerase γ (Pol γ) is the only polymerase known to replicate the mitochondrial genome. The Pol γ holoenzyme consists of the p140 catalytic subunit (POLG) and the p55 homodimeric accessory subunit (POLG2), which enhances binding of Pol γ to DNA and promotes processivity of the holoenzyme. Mutations within POLG impede maintenance of mtDNA and cause mitochondrial diseases. Two common POLG mutations usually found in cis in patients primarily with progressive external ophthalmoplegia generate T251I and P587L amino acid substitutions. To determine whether T251I or P587L is the primary pathogenic allele or whether both substitutions are required to cause disease, we overproduced and purified WT, T251I, P587L, and T251I + P587L double variant forms of recombinant Pol γ. Biochemical characterization of these variants revealed impaired DNA binding affinity, reduced thermostability, diminished exonuclease activity, defective catalytic activity, and compromised DNA processivity, even in the presence of the p55 accessory subunit. However, physical association with p55 was unperturbed, suggesting intersubunit affinities similar to WT. Notably, although the single mutants were similarly impaired, a dramatic synergistic effect was found for the double mutant across all parameters. In conclusion, our analyses suggest that individually both T251I and P587L substitutions functionally impair Pol γ, with greater pathogenicity predicted for the single P587L variant. Combining T251I and P587L induces extreme thermal lability and leads to synergistic nucleotide and DNA binding defects, which severely impair catalytic activity and correlate with presentation of disease in patients. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Bovine and murine models highlight novel roles for SLC25A46 in mitochondrial dynamics and metabolism, with implications for human and animal health.

    Directory of Open Access Journals (Sweden)

    Amandine Duchesne

    2017-04-01

    Full Text Available Neuropathies are neurodegenerative diseases affecting humans and other mammals. Many genetic causes have been identified so far, including mutations of genes encoding proteins involved in mitochondrial dynamics. Recently, the "Turning calves syndrome", a novel sensorimotor polyneuropathy was described in the French Rouge-des-Prés cattle breed. In the present study, we determined that this hereditary disease resulted from a single nucleotide substitution in SLC25A46, a gene encoding a protein of the mitochondrial carrier family. This mutation caused an apparent damaging amino-acid substitution. To better understand the function of this protein, we knocked out the Slc25a46 gene in a mouse model. This alteration affected not only the nervous system but also altered general metabolism, resulting in premature mortality. Based on optic microscopy examination, electron microscopy and on biochemical, metabolic and proteomic analyses, we showed that the Slc25a46 disruption caused a fusion/fission imbalance and an abnormal mitochondrial architecture that disturbed mitochondrial metabolism. These data extended the range of phenotypes associated with Slc25a46 dysfunction. Moreover, this Slc25a46 knock-out mouse model should be useful to further elucidate the role of SLC25A46 in mitochondrial dynamics.

  14. Three dimensional reconstruction of the human skeletal muscle mitochondrial network as a tool to assess mitochondrial content and structural organization

    DEFF Research Database (Denmark)

    Dahl, Rannvá; Larsen, Steen; Dohlmann, Tine L

    2015-01-01

    Mitochondria undergo continuous changes in shape as result of complex fusion and fission processes. The physiological relevance of mitochondrial dynamics is still unclear. In the field of mitochondria bioenergetics, there is a need of tools to assess cell mitochondrial content. Aim: Develop...... mitochondrial dynamics in response to life-style interventions and/or in certain pathologies. Our results question the classification of mitochondria into subsarcolemmal and intermyofibrillar pools, since they are physically interconnected. This article is protected by copyright. All rights reserved....

  15. Mitochondrial DNA copy number variation across human cancers.

    Science.gov (United States)

    Reznik, Ed; Miller, Martin L; Şenbabaoğlu, Yasin; Riaz, Nadeem; Sarungbam, Judy; Tickoo, Satish K; Al-Ahmadie, Hikmat A; Lee, William; Seshan, Venkatraman E; Hakimi, A Ari; Sander, Chris

    2016-02-22

    Mutations, deletions, and changes in copy number of mitochondrial DNA (mtDNA), are observed throughout cancers. Here, we survey mtDNA copy number variation across 22 tumor types profiled by The Cancer Genome Atlas project. We observe a tendency for some cancers, especially of the bladder, breast, and kidney, to be depleted of mtDNA, relative to matched normal tissue. Analysis of genetic context reveals an association between incidence of several somatic alterations, including IDH1 mutations in gliomas, and mtDNA content. In some but not all cancer types, mtDNA content is correlated with the expression of respiratory genes, and anti-correlated to the expression of immune response and cell-cycle genes. In tandem with immunohistochemical evidence, we find that some tumors may compensate for mtDNA depletion to sustain levels of respiratory proteins. Our results highlight the extent of mtDNA copy number variation in tumors and point to related therapeutic opportunities.

  16. Mitochondrial DNA background modulates the assembly kinetics of OXPHOS complexes in a cellular model of mitochondrial disease.

    NARCIS (Netherlands)

    Pello, R.; Martin, M.A.; Carelli, V.; Nijtmans, L.G.J.; Achilli, A.; Pala, M.; Torroni, A.; Gomez-Duran, A.; Ruiz-Pesini, E.; Martinuzzi, A.; Smeitink, J.A.M.; Arenas, J.; Ugalde, C.

    2008-01-01

    Leber's hereditary optic neuropathy (LHON), the most frequent mitochondrial disorder, is mostly due to three mitochondrial DNA (mtDNA) mutations in respiratory chain complex I subunit genes: 3460/ND1, 11778/ND4 and 14484/ND6. Despite considerable clinical evidences, a genetic modifying role of the

  17. Iron–sulfur cluster biogenesis and human disease

    Science.gov (United States)

    Rouault, Tracey A.; Tong, Wing Hang

    2008-01-01

    Iron–sulfur (Fe–S) clusters are essential for numerous biological processes, including mitochondrial respiratory chain activity and various other enzymatic and regulatory functions. Human Fe–S cluster assembly proteins are frequently encoded by single genes, and inherited defects in some of these genes cause disease. Recently, the spectrum of diseases attributable to abnormal Fe–S cluster biogenesis has extended beyond Friedreich ataxia to include a sideroblastic anemia with deficiency of glutaredoxin 5 and a myopathy associated with a deficiency of a Fe–S cluster assembly scaffold protein, ISCU. Mutations within other mammalian Fe–S cluster assembly genes could be causative for human diseases that manifest distinctive combinations of tissue-specific impairments. Thus, defects in the iron–sulfur cluster biogenesis pathway could underlie many human diseases. PMID:18606475

  18. Mitochondrial Dysfunction: A Basic Mechanism in Inflammation-Related Non-Communicable Diseases and Therapeutic Opportunities

    Directory of Open Access Journals (Sweden)

    Anna Hernández-Aguilera

    2013-01-01

    Full Text Available Obesity is not necessarily a predisposing factor for disease. It is the handling of fat and/or excessive energy intake that encompasses the linkage of inflammation, oxidation, and metabolism to the deleterious effects associated with the continuous excess of food ingestion. The roles of cytokines and insulin resistance in excessive energy intake have been studied extensively. Tobacco use and obesity accompanied by an unhealthy diet and physical inactivity are the main factors that underlie noncommunicable diseases. The implication is that the management of energy or food intake, which is the main role of mitochondria, is involved in the most common diseases. In this study, we highlight the importance of mitochondrial dysfunction in the mutual relationships between causative conditions. Mitochondria are highly dynamic organelles that fuse and divide in response to environmental stimuli, developmental status, and energy requirements. These organelles act to supply the cell with ATP and to synthesise key molecules in the processes of inflammation, oxidation, and metabolism. Therefore, energy sensors and management effectors are determinants in the course and development of diseases. Regulating mitochondrial function may require a multifaceted approach that includes drugs and plant-derived phenolic compounds with antioxidant and anti-inflammatory activities that improve mitochondrial biogenesis and act to modulate the AMPK/mTOR pathway.

  19. Soil Borne Human Diseases

    NARCIS (Netherlands)

    Jeffery, Simon; Van der Putten, Wim H.

    2011-01-01

    Soils are home to a remarkable array of biodiversity with some estimates stating that 25% of the Earth’s species find their home in the soil. Of these organisms, the vast majority are not of any threat to human health, but rather function to provide numerous ecosystem services which emerge through

  20. Mitochondrial DNA deletion associated with the reduction of adenine nucleotides in human atrium and atrial fibrillation.

    Science.gov (United States)

    Tsuboi, M; Hisatome, I; Morisaki, T; Tanaka, M; Tomikura, Y; Takeda, S; Shimoyama, M; Ohtahara, A; Ogino, K; Igawa, O; Shigemasa, C; Ohgi, S; Nanba, E

    2001-06-01

    Structural changes in the number, size, and shape of mitochondria (mt) have been observed in the atrial muscles of patients with atrial fibrillation (AF) and of animals with rapid atrial pacing, however, it is not known whether the mitochondrial function is impaired in human atrium with AF. We determined adenine nucleotides concentrations and mtDNA deletions in 26 human right atria obtained at the time of cardiac surgery, using HPLC and PCR amplification, and studied the relationship between mtDNA deletions and clinical manifestations, the haemodynamic parameters of the patients and adenine nucleotide concentrations in their atrium. The age and the prevalence of AF were significantly higher in the patients with a mtDNA deletion of 7.4 kb than in those without a deletion; there were no significant differences regarding haemodynamic parameters between the two groups. The concentrations of ATP, ADP, AMP and total adenine nucleotides in the right atrium were significantly lower in the patients with mtDNA deletions than the patients without a deletion. In a gender- and diseased-matched population, the mtDNA deletion was still significantly associated with age and a decreased concentration of adenine nucleotides in the atrium. Using quantitative PCR analysis, the proportion of mtDNA deletion to normal mtDNA of the atrium, was estimated to be 0.3-2% in four cases. These results suggest that the deletion of mtDNA associated with ageing or AF can lead to a bioenergetic deficiency due to an impaired ATP synthesis in the human atrium; however, no conclusion can be made whether mtDNA deletion were the result or the cause of an impaired ATP synthesis, ageing, hemodynamic deterioration, or AF.

  1. LC-MS Analysis of Human Platelets as a Platform for Studying Mitochondrial Metabolism.

    Science.gov (United States)

    Worth, Andrew J; Marchione, Dylan M; Parry, Robert C; Wang, Qingqing; Gillespie, Kevin P; Saillant, Noelle N; Sims, Carrie; Mesaros, Clementina; Snyder, Nathaniel W; Blair, Ian A

    2016-04-04

    Perturbed mitochondrial metabolism has received renewed interest as playing a causative role in a range of diseases. Probing alterations to metabolic pathways requires a model in which external factors can be well controlled, allowing for reproducible and meaningful results. Many studies employ transformed cellular models for these purposes; however, metabolic reprogramming that occurs in many cancer cell lines may introduce confounding variables. For this reason primary cells are desirable, though attaining adequate biomass for metabolic studies can be challenging. Here we show that human platelets can be utilized as a platform to carry out metabolic studies in combination with liquid chromatography-tandem mass spectrometry analysis. This approach is amenable to relative quantification and isotopic labeling to probe the activity of specific metabolic pathways. Availability of platelets from individual donors or from blood banks makes this model system applicable to clinical studies and feasible to scale up. Here we utilize isolated platelets to confirm previously identified compensatory metabolic shifts in response to the complex I inhibitor rotenone. More specifically, a decrease in glycolysis is accompanied by an increase in fatty acid oxidation to maintain acetyl-CoA levels. Our results show that platelets can be used as an easily accessible and medically relevant model to probe the effects of xenobiotics on cellular metabolism.

  2. Induction of Mitochondrial Changes Associated with Oxidative Stress on Very Long Chain Fatty Acids (C22:0, C24:0, or C26:0-Treated Human Neuronal Cells (SK-NB-E

    Directory of Open Access Journals (Sweden)

    Amira Zarrouk

    2012-01-01

    Full Text Available In Alzheimer's disease, lipid alterations point towards peroxisomal dysfunctions. Indeed, a cortical accumulation of saturated very long chain fatty acids (VLCFAs: C22:0, C24:0, C26:0, substrates for peroxisomal β-oxidation, has been found in Alzheimer patients. This study was realized to investigate the effects of VLCFAs at the mitochondrial level since mitochondrial dysfunctions play crucial roles in neurodegeneration. On human neuronal SK-NB-E cells treated with C22:0, C24:0, or C26:0 (0.1–20 μM; 48 h, an inhibition of cell growth and mitochondrial dysfunctions were observed by cell counting with trypan blue, MTT assay, and measurement of mitochondrial transmembrane potential (Δψm with DiOC6(3. A stimulation of oxidative stress was observed with DHE and MitoSOX used to quantify superoxide anion production on whole cells and at the mitochondrial level, respectively. With C24:0 and C26:0, by Western blotting, lower levels of mitochondrial complexes III and IV were detected. After staining with MitoTracker and by transmission electron microscopy used to study mitochondrial topography, mass and morphology, major changes were detected in VLCFAs treated-cells: modification of the cytoplasmic distribution of mitochondria, presence of large mitochondria, enhancement of the mitochondrial mass. Thus, VLCFAs can be potential risk factors contributing to neurodegeneration by inducing neuronal damages via mitochondrial dysfunctions.

  3. Major growth reduction and minor decrease in mitochondrial enzyme activity in cultured human muscle cells after exposure to zidovudine.

    Science.gov (United States)

    Herzberg, N H; Zorn, I; Zwart, R; Portegies, P; Bolhuis, P A

    1992-06-01

    Zidovudine-induced mitochondrial myopathy in AIDS patients reported recently might be due to inhibition of mitochondrial DNA polymerase gamma. We investigated the effect of zidovudine on proliferation, differentiation, activity of mitochondrial- and nuclear-encoded enzymes, and mitochondrial DNA (mtDNA), in cultured human muscle cells. Marked inhibition of cell proliferation was found, even in the presence of low (10 mumol/L) zidovudine concentrations. Enzyme activity of the nuclear-encoded mitochondrial citrate synthase was not affected, and the partially mitochondrial-encoded cytochrome c oxidase was not decreased, except only after exposure to high concentrations (5 mmol/L) zidovudine. No decrease of mtDNA content and no mtDNA deletions were found in zidovudine-exposed muscle cells. We propose that the effect of zidovudine on muscle, seen in zidovudine-treated AIDS patients, results mainly from decrease in proliferation of muscle cells rather than inhibition of mtDNA replication.

  4. Heterologous expression of human carnitine palmitoyltransferase (CPT) II in yeast: A model for the molecular analysis of mitochondrial fatty acid oxidation defects

    Energy Technology Data Exchange (ETDEWEB)

    Cavadini, P.; Invernizzi, F.; Baratta, S. [Istituto Nazionale Neurologico Carlo Besta, Milano (Italy)] [and others

    1994-09-01

    The CPT enzyme system, which is composed of two distinct mitochondrial membrane-bound proteins (CPT I and CPT II), provides the mechanism whereby long-chain fatty acids are transferred from the cytosol to the mitochondrial matrix to undergo {beta}-oxidation. Here, we report the development of an expression system for investigating genotype/phenotype correlations in CPT II deficiency and, potentially, other mitochondrial fatty acid oxidation defects. To explore yeast as an expression system, we introduced a cDNA encoding the entire human CPT II precursor into Saccharomyces cerevisiae. Expression was programmed by using an inducible galactose operon promoter (GAL1). Following induction, human CPT II was expressed at high levels, with activity 4- to 16-fold greater than in human fibroblasts. Levels of expression paralleled those of respiration, being higher in cells grown on a nonfermentable carbon source than in those grown on glucose. Immunoprecipitation of pulse-labeled transformed cells demonstrated that human CPT II expressed in yeast was targeted to mitochondria with correct proteolytic processing of its 25-residue mitochondrial leader sequence. Preliminary results on the expression of a number of mutant CPT II alleles associated with different clinical phenotypes demonstrated the value of this system for examining the functional consequences of disease-causing mutations and investigating genotype/phenotype correlations in patients with CPT II deficiency.

  5. The Newcastle Pediatric Mitochondrial Disease Scale: translation and cultural adaptation for use in Brazil.

    Science.gov (United States)

    Campolina-Sampaio, Gabriela Palhares; Lasmar, Laura Maria de Lima Belizário Facury; Ribeiro, Beatriz Silva Vilela; Giannetti, Juliana Gurgel

    2016-11-01

    The aim of this study was to translate and adapt the Newcastle Paediatric Mitochondrial Disease Scale (NPMDS) to Portuguese for use in Brazil. The scale was applied in 20 pediatric patients with mitochondrial disease, in three groups: myopathy (n = 4); Leigh syndrome (n = 8); and encephalomyopathy (n = 8). Scores were obtained for the various dimensions of the NPMDS, and comparisons were drawn between the groups. There was a statistically significant difference between the myopathy group and the Leigh syndrome group (p = 0.0085), as well as between the myopathy and encephalomyopathy groups (p = 0.01). The translation of the NPMDS, and its adaptation to the socioeconomic and cultural conditions in Brazil, make the NPMDS score useful as an additional parameter in the evaluation and monitoring of pediatric patients with MD in Brazil.

  6. Mitochondrial Kinases in Parkinson's Disease: Converging Insights from Neurotoxin and Genetic Models

    Science.gov (United States)

    Dagda, Ruben K.; Zhu, Jianhui; Chu, Charleen T.

    2009-01-01

    Alterations in mitochondrial biology have long been implicated in neurotoxin, and more recently, genetic models of parkinsonian neurodegeneration. In particular, kinase regulation of mitochondrial dynamics and turnover are emerging as central mechanisms at the convergence of neurotoxin, environmental and genetic approaches to studying Parkinson's disease (PD). Kinases that localize to mitochondria during neuronal injury include mitogen activated protein kinases (MAPK) such as extracellular signal regulated protein kinases (ERK) and c-Jun N-terminal kinases (JNK), protein kinase B/Akt, and PTEN-induced kinase 1 (PINK1). Although site(s) of action within mitochondria and specific kinase targets are still unclear, these signaling pathways regulate mitochondrial respiration, transport, fission-fusion, calcium buffering, reactive oxygen species (ROS) production, mitochondrial autophagy and apoptotic cell death. In this review, we summarize accelerating experimental evidence gathered over the last decade that implicate a central role for kinase signaling at the mitochondrion in Parkinson's and related neurodegenerative disorders. Interactions involving α-synuclein, leucine rich repeat kinase 2 (LRRK2), DJ-1 and parkin are discussed. Converging mechanisms from different model systems support the concept of common pathways in parkinsonian neurodegeneration that may be amenable to future therapeutic interventions. PMID:19563915

  7. Chemical Compensation of Mitochondrial Phospholipid Depletion in Yeast and Animal Models of Parkinson?s Disease

    OpenAIRE

    Wang, Shaoxiao; Zhang, Siyuan; Xu, Chuan; Barron, Addie; Galiano, Floyd; Patel, Dhaval; Lee, Yong Joo; Caldwell, Guy A.; Caldwell, Kim A.; Witt, Stephan N.

    2016-01-01

    We have been investigating the role that phosphatidylethanolamine (PE) and phosphatidylcholine (PC) content plays in modulating the solubility of the Parkinson?s disease protein alpha-synuclein (?-syn) using Saccharomyces cerevisiae and Caenorhabditis elegans. One enzyme that synthesizes PE is the conserved enzyme phosphatidylserine decarboxylase (Psd1/yeast; PSD-1/worms), which is lodged in the inner mitochondrial membrane. We previously found that decreasing the level of PE due to knockdown...

  8. A Novel Class of Tests for the Detection of Mitochondrial DNA–Mutation Involvement in Diseases

    OpenAIRE

    Sun, Fengzhu; Cui, Jing; Gavras, Haralambos; Schwartz, Faina

    2003-01-01

    We develop a novel class of tests to detect mitochondrial DNA (mtDNA)–mutation involvement in complex diseases by the study of affected pedigree members. For a pedigree, affected individuals are first considered and are then connected through their relatives. We construct a reduced pedigree from an original pedigree. Each configuration of a reduced pedigree is given a score, with high scores given to configurations that are consistent with mtDNA-mutation involvement and low scores given to co...

  9. The advances and new technologies for the study of mitochondrial diseases.

    Science.gov (United States)

    Bianco, Bianca; Montagna, Erik

    2016-01-01

    ABSTRACTGenetic mitochondrial disorders are responsible for the most common inborn errors of metabolism, caused by mutations in either nuclear genes or in mitochondrial DNA. This article presents the prokaryotic origin of the organelle and the relation between nuclear and mitochondrial genomes, as well as current evolutionary models for such mechanisms. It also addresses the structure of mitochondrial genes, their expression pattern, clinical features of gene defects, risk of transmission and current techniques to avoid these events in assisted human reproduction. Finally, it discusses the ethical implications of these possibilities.RESUMOAs doenças genéticas mitocondriais são responsáveis pelos erros inatos do metabolismo mais comuns, causados por mutações tanto em genes nucleares como no DNA mitocondrial. Este artigo apresenta a origem procariótica dessa organela, e a relação entre os genomas nuclear e mitocondrial, bem como modelos evolutivos correntes para esses mecanismos. Também trata da estrutura dos genes mitocondriais, seu padrão de expressão, características clínicas de defeitos genéticos, riscos de transmissão e técnicas atualmente utilizadas para evitar esses eventos em reprodução humana assistida. Finalmente, discute as implicações éticas dessas possibilidades.

  10. 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

    AIM: To evaluate the association with diabetic kidney disease of single nucleotide polymorphisms (SNPs) that may contribute to mitochondrial dysfunction. METHODS: The mitochondrial genome and 1039 nuclear genes that are integral to mitochondrial function were investigated using a case (n = 823...... 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...... phenotypes to those of the discovery collection. Association analyses were performed using the plink genetic analysis toolset, with adjustment for relevant covariates. RESULTS: A total of 25 SNPs were evaluated in the mitochondrial genome, but none were significantly associated with diabetic kidney disease...

  11. Viral diseases and human evolution

    Directory of Open Access Journals (Sweden)

    Leal Élcio de Souza

    2000-01-01

    Full Text Available The interaction of man with viral agents was possibly a key factor shaping human evolution, culture and civilization from its outset. Evidence of the effect of disease, since the early stages of human speciation, through pre-historical times to the present suggest that the types of viruses associated with man changed in time. As human populations progressed technologically, they grew in numbers and density. As a consequence different viruses found suitable conditions to thrive and establish long-lasting associations with man. Although not all viral agents cause disease and some may in fact be considered beneficial, the present situation of overpopulation, poverty and ecological inbalance may have devastating effets on human progress. Recently emerged diseases causing massive pandemics (eg., HIV-1 and HCV, dengue, etc. are becoming formidable challenges, which may have a direct impact on the fate of our species.

  12. RCAN1 overexpression promotes age-dependent mitochondrial dysregulation related to neurodegeneration in Alzheimer’s disease

    Science.gov (United States)

    Wong, Helen; Levenga, Josien; Cain, Peter; Rothermel, Beverly; Klann, Eric

    2016-01-01

    Aging is the largest risk factor for Alzheimer’s disease (AD). Patients with Down syndrome (DS) develop symptoms consistent with early-onset AD, suggesting that overexpression of chromosome 21 genes such as Regulator of Calcineurin 1 (RCAN1) plays a role in AD pathogenesis. RCAN1 levels are increased in the brain of DS and AD patients but also in the human brain with normal aging. RCAN1 has been implicated in several neuronal functions, but whether its increased expression is correlative or causal in the aging-related progression of AD remains elusive. We show that brain-specific overexpression of the human RCAN1.1S isoform in mice promotes early age-dependent memory and synaptic plasticity deficits, tau pathology, and dysregulation of dynamin-related protein 1 (DRP1) activity associated with mitochondrial dysfunction and oxidative stress, reproducing key AD features. Based on these findings, we propose that chronic RCAN1 overexpression during aging alters DRP1-mediated mitochondrial fission and thus acts to promote AD-related progressive neurodegeneration. PMID:26497675

  13. Mitochondrial vasculopathy.

    Science.gov (United States)

    Finsterer, Josef; Zarrouk-Mahjoub, Sinda

    2016-05-26

    Mitochondrial disorders (MIDs) are usually multisystem disorders (mitochondrial multiorgan disorder syndrome) either on from onset or starting at a point during the disease course. Most frequently affected tissues are those with a high oxygen demand such as the central nervous system, the muscle, endocrine glands, or the myocardium. Recently, it has been shown that rarely also the arteries may be affected (mitochondrial arteriopathy). This review focuses on the type, diagnosis, and treatment of mitochondrial vasculopathy in MID patients. A literature search using appropriate search terms was carried out. Mitochondrial vasculopathy manifests as either microangiopathy or macroangiopathy. Clinical manifestations of mitochondrial microangiopathy include leukoencephalopathy, migraine-like headache, stroke-like episodes, or peripheral retinopathy. Mitochondrial macroangiopathy manifests as atherosclerosis, ectasia of arteries, aneurysm formation, dissection, or spontaneous rupture of arteries. The diagnosis relies on the documentation and confirmation of the mitochondrial metabolic defect or the genetic cause after exclusion of non-MID causes. Treatment is not at variance compared to treatment of vasculopathy due to non-MID causes. Mitochondrial vasculopathy exists and manifests as micro- or macroangiopathy. Diagnosing mitochondrial vasculopathy is crucial since appropriate treatment may prevent from severe complications.

  14. Preferential killing of human lung cancer cell lines with mitochondrial dysfunction by nonthermal dielectric barrier discharge plasma

    Science.gov (United States)

    Panngom, K; Baik, K Y; Nam, M K; Han, J H; Rhim, H; Choi, E H

    2013-01-01

    The distinctive cellular and mitochondrial dysfunctions of two human lung cancer cell lines (H460 and HCC1588) from two human lung normal cell lines (MRC5 and L132) have been studied by dielectric barrier discharge (DBD) plasma treatment. This cytotoxicity is exposure time-dependent, which is strongly mediated by the large amount of H2O2 and NOx in culture media generated by DBD nonthermal plasma. It is found that the cell number of lung cancer cells has been reduced more than that of the lung normal cells. The mitochondrial vulnerability to reactive species in H460 may induce distinctively selective responses. Differential mitochondrial membrane potential decrease, mitochondrial enzymatic dysfunction, and mitochondrial morphological alteration are exhibited in two cell lines. These results suggest the nonthermal plasma treatment as an efficacious modality in lung cancer therapy. PMID:23703387

  15. Activation-dependent mitochondrial translocation of Foxp3 in human hepatocytes

    Energy Technology Data Exchange (ETDEWEB)

    Rojas, Joselyn; Teran-Angel, Guillermo; Barbosa, Luisa [Instituto de Inmunología Clínica, Facultad de Medicina, Universidad de Los Andes, Merida (Venezuela, Bolivarian Republic of); Peterson, Darrell L. [Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA (United States); Berrueta, Lisbeth, E-mail: lberruet@ula.ve [Instituto de Inmunología Clínica, Facultad de Medicina, Universidad de Los Andes, Merida (Venezuela, Bolivarian Republic of); Division of Preventive Medicine, Brigham and Women' s Hospital, Harvard Medical School, Boston, MA (United States); Salmen, Siham, E-mail: sihamsa@ula.ve [Instituto de Inmunología Clínica, Facultad de Medicina, Universidad de Los Andes, Merida (Venezuela, Bolivarian Republic of)

    2016-05-01

    Foxp3 is considered to be the master regulator for the development and function of regulatory T cells (Treg). Recently Foxp3, has been detected in extra lymphoid tissue, and in hepatocytes and has been associated with hepatocellular carcinoma (HCC), although its role has not been defined. Since it is expected that there is a relationship between protein localization, activity and cellular function, the aim of this study was to explore the subcellular localization of Foxp3 in resting and stimulated human hepatocytes. Foxp3 expression was measured by flow cytometry, subcellular fractioning, and immunofluorescence, and this data was used to track the shuttling of Foxp3 in different subcellular compartments in hepatocytes (HepG2 cell line), stimulated by using the PKC activators (PMA), core and preS1/2 antigen from hepatitis B virus (HBV). Our data shows that besides the nuclear location, mitochondrial translocation was detected after stimulation with PMA and at to a lesser extent, with preS1/2. In addition, Foxp3 is localizes at outer mitochondrial membrane. These results suggest a non-canonical role of Foxp3 in the mitochondrial compartment in human hepatocytes, and opens a new field about their role in liver damages during HBV infection. - Highlights: • The expression and subcellular distribution of Foxp3, is modulated by PMA and preS1/2. • PMA and preS1/2 increase Foxp3 expression on HepG2. • PMA and preS1/2 induce foxp3 enrichment at mitochondrial, microsomal and nuclear compartments. • Results suggest a non-canonical function of Foxp3 or a mitochondrial transcriptional activity.

  16. Desmin common mutation is associated with multi-systemic disease manifestations and depletion of mitochondria and mitochondrial DNA

    Directory of Open Access Journals (Sweden)

    Elizabeth eMcCormick

    2015-06-01

    Full Text Available Desmin (DES is a major muscle scaffolding protein that also functions to anchor mitochondria. Pathogenic DES mutations, however, have not previously been recognized as a cause of multi-systemic mitochondrial disease. Here, we describe a 45-year-old man who presented to The Children’s Hospital of Philadelphia Mitochondrial-Genetics Diagnostic Clinic for evaluation of progressive cardiac, neuromuscular, gastrointestinal, and mood disorders. Muscle biopsy at age 45 was remarkable for cytoplasmic bodies, as well as ragged red fibers and SDH positive/COX negative fibers that were suggestive of a mitochondrial myopathy. Muscle also showed significant reductions in mitochondrial content (16% of control mean for citrate synthase activity and mitochondrial DNA (35% of control mean. His family history was significant for cardiac conduction defects and myopathy in multiple maternal relatives. Multiple single gene and panel-based sequencing studies were unrevealing. Whole exome sequencing identified a known pathogenic p.S13F mutation in DES that had previously been associated with desmin-related myopathy. Desmin-related myopathy is an autosomal dominant disorder characterized by right ventricular hypertrophic cardiomyopathy, myopathy, and arrhythmias. However, neuropathy, gastrointestinal dysfunction, and depletion of both mitochondria and mitochondrial DNA have not previously been widely recognized in this disorder. Recognition that mitochondrial dysfunction occurs in desmin-related myopathy clarifies the basis for the multi-systemic manifestations, as are typical of primary mitochondrial disorders. Understanding the mitochondrial pathophysiology of desmin-related myopathy highlights the possibility of new therapies for the otherwise untreatable and often fatal class of disease. We postulate that drug treatments aimed at improving mitochondrial biogenesis or reducing oxidative stress may be effective therapies to ameliorate the effects of desmin

  17. Liver mitochondrial dysfunction and oxidative stress in the pathogenesis of experimental nonalcoholic fatty liver disease

    Directory of Open Access Journals (Sweden)

    Oliveira C.P.M.S.

    2006-01-01

    Full Text Available Oxidative stress and hepatic mitochondria play a role in the pathogenesis of nonalcoholic fatty liver disease. The aim of the present study was to evaluate the role of hepatic mitochondrial dysfunction and oxidative stress in the pathogenesis of the disease. Fatty liver was induced in Wistar rats with a choline-deficient diet (CD; N = 7 or a high-fat diet enriched with PUFAs-omega-3 (H; N = 7 for 4 weeks. The control group (N = 7 was fed a standard diet. Liver mitochondrial oxidation and phosphorylation were measured polarographically and oxidative stress was estimated on the basis of malondialdehyde and glutathione concentrations. Moderate macrovacuolar liver steatosis was observed in the CD group and mild liver steatosis was observed in the periportal area in the H group. There was an increase in the oxygen consumption rate by liver mitochondria in respiratory state 4 (S4 and a decrease in respiratory control rate (RCR in the CD group (S4: 32.70 ± 3.35; RCR: 2.55 ± 0.15 ng atoms of O2 min-1 mg protein-1 when compared to the H and control groups (S4: 23.09 ± 1.53, 17.04 ± 2.03, RCR: 3.15 ± 0.15, 3.68 ± 0.15 ng atoms of O2 min-1 mg protein-1, respectively, P < 0.05. Hepatic lipoperoxide concentrations were significantly increased and the concentration of reduced glutathione was significantly reduced in the CD group. A choline-deficient diet causes moderate steatosis with disruption of liver mitochondrial function and increased oxidative stress. These data suggest that lipid peroxidation products can impair the flow of electrons along the respiratory chain, causing overreduction of respiratory chain components and enhanced mitochondrial reactive oxygen species. These findings are important in the pathogenesis of nonalcoholic fatty liver disease.

  18. Altered Expression of Human Mitochondrial Branched Chain Aminotransferase in Dementia with Lewy Bodies and Vascular Dementia.

    Science.gov (United States)

    Ashby, Emma L; Kierzkowska, Marta; Hull, Jonathon; Kehoe, Patrick G; Hutson, Susan M; Conway, Myra E

    2017-01-01

    Cytosolic and mitochondrial human branched chain aminotransferase (hBCATc and hBCATm, respectively) play an integral role in brain glutamate metabolism. Regional increased levels of hBCATc in the CA1 and CA4 region of Alzheimer's disease (AD) brain together with increased levels of hBCATm in frontal and temporal cortex of AD brains, suggest a role for these proteins in glutamate excitotoxicity. Glutamate toxicity is a key pathogenic feature of several neurological disorders including epilepsy associated dementia, AD, vascular dementia (VaD) and dementia with Lewy bodies (DLB). To further understand if these increases are specific to AD, the expression profiles of hBCATc and hBCATm were examined in other forms of dementia including DLB and VaD. Similar to AD, levels of hBCATm were significantly increased in the frontal and temporal cortex of VaD cases and in frontal cortex of DLB cases compared to controls, however there were no observed differences in hBCATc between groups in these areas. Moreover, multiple forms of hBCATm were observed that were particular to the disease state relative to matched controls. Real-time PCR revealed similar expression of hBCATm mRNA in frontal and temporal cortex for all cohort comparisons, whereas hBCATc mRNA expression was significantly increased in VaD cases compared to controls. Collectively our results suggest that hBCATm protein expression is significantly increased in the brains of DLB and VaD cases, similar to those reported in AD brain. These findings indicate a more global response to altered glutamate metabolism and suggest common metabolic responses that might reflect shared neurodegenerative mechanisms across several forms of dementia.

  19. Evaluation of a Mitochondrial DNA Mutation in Maternally Inherited and Sporadic Cases of Dupuytren Disease

    Science.gov (United States)

    Anderson, Eric R.; Burmester, James K.; Caldwell, Michael D.

    2012-01-01

    Objective The purpose was to test the hypothesis that Dupuytren disease (DD) is associated with a previously reported mutation in mitochondrial DNA at position 2839. Methods Two hundred sixty-nine cases of DD and an equal number of matched controls were identified in Marshfield Clinic’s Personalized Medicine Research Project (PMRP). Clinical data used to describe the cohort were abstracted from the electronic medical records of the population. Genetic analysis of all the cases and controls was done using a custom synthesis TaqMan assay, while genetic analysis of sixteen of the above cases with a familial history of DD was performed by mitochondrial DNA sequencing at position C2839A. Results Cases and controls were evenly distributed with 167 (62%) men and 102 (38%) women. The majority, 264 (98%) of the cases and controls were white non-Hispanic. Of the 269 cases, 16 were found to have a familial history of DD. Two cases had a maternal history, eight a paternal history, five an affected sibling, and one a paternal grandfather. All cases and controls were found to have only the C allele at the site of the reported mitochondrial C2839A polymorphism. Conclusions The previously reported mitochondrial mutation was not present in our small, maternally inherited cohort or in the total population of 538 cases and controls. This finding does not support the reported incidence of this polymorphism in 90% of the affected population with a maternal inheritance, and calls into question the role of the C2839A mitochondrial DNA polymorphism in familial or sporadic cases of DD. PMID:22634541

  20. NOX4 NADPH Oxidase-Dependent Mitochondrial Oxidative Stress in Aging-Associated Cardiovascular Disease.

    Science.gov (United States)

    Vendrov, Aleksandr E; Vendrov, Kimberly C; Smith, Alberto; Yuan, Jinling; Sumida, Arihiro; Robidoux, Jacques; Runge, Marschall S; Madamanchi, Nageswara R

    2015-12-20

    Increased oxidative stress and vascular inflammation are implicated in increased cardiovascular disease (CVD) incidence with age. We and others demonstrated that NOX1/2 NADPH oxidase inhibition, by genetic deletion of p47phox, in Apoe(-/-) mice decreases vascular reactive oxygen species (ROS) generation and atherosclerosis in young age. The present study examined whether NOX1/2 NADPH oxidases are also pivotal to aging-associated CVD. Both aged (16 months) Apoe(-/-) and Apoe(-/-)/p47phox(-/-) mice had increased atherosclerotic lesion area, aortic stiffness, and systolic dysfunction compared with young (4 months) cohorts. Cellular and mitochondrial ROS (mtROS) levels were significantly higher in aortic wall and vascular smooth muscle cells (VSMCs) from aged wild-type and p47phox(-/-) mice. VSMCs from aged mice had increased mitochondrial protein oxidation and dysfunction and increased vascular cell adhesion molecule 1 expression, which was abrogated with (2-(2,2,6,6-Tetramethylpiperidin-1-oxyl-4-ylamino)-2-oxoethyl)triphenylphosphonium chloride (MitoTEMPO) treatment. NOX4 expression was increased in the vasculature and mitochondria of aged mice and its suppression with shRNA in VSMCs from aged mice decreased mtROS levels and improved function. Increased mtROS levels were associated with enhanced mitochondrial NOX4 expression in aortic VSMCs from aged subjects, and NOX4 expression levels in arterial wall correlated with age and atherosclerotic severity. Aged Apoe(-/-) mice treated with MitoTEMPO and 2-(2-chlorophenyl)-4-methyl-5-(pyridin-2-ylmethyl)-1H-pyrazolo[4,3-c]pyridine-3,6(2H,5H)-dione had decreased vascular ROS levels and atherosclerosis and preserved vascular and cardiac function. These data suggest that NOX4, but not NOX1/2, and mitochondrial oxidative stress are mediators of CVD in aging under hyperlipidemic conditions. Regulating NOX4 activity/expression and using mitochondrial antioxidants are potential approaches to reducing aging-associated CVD.

  1. Effects of endurance training on skeletal muscle mitochondrial function in Huntington disease patients.

    Science.gov (United States)

    Mueller, Sandro Manuel; Gehrig, Saskia Maria; Petersen, Jens A; Frese, Sebastian; Mihaylova, Violeta; Ligon-Auer, Maria; Khmara, Natalia; Nuoffer, Jean-Marc; Schaller, André; Lundby, Carsten; Toigo, Marco; Jung, Hans H

    2017-12-19

    Mitochondrial dysfunction may represent a pathogenic factor in Huntington disease (HD). Physical exercise leads to enhanced mitochondrial function in healthy participants. However, data on effects of physical exercise on HD skeletal muscle remains scarce. We aimed at investigating adaptations of the skeletal muscle mitochondria to endurance training in HD patients. Thirteen HD patients and 11 healthy controls completed 26 weeks of endurance training. Before and after the training phase muscle biopsies were obtained from M. vastus lateralis. Mitochondrial respiratory chain complex activities, mitochondrial respiratory capacity, capillarization, and muscle fiber type distribution were determined from muscle samples. Citrate synthase activity increased during the training intervention in the whole cohort (P = 0.006). There was no group x time interaction for citrate synthase activity during the training intervention (P = 0.522). Complex III (P = 0.008), Complex V (P = 0.043), and succinate cytochrome c reductase (P = 0.008) activities increased in HD patients and controls by endurance training. An increase in mass-specific mitochondrial respiratory capacity was present in HD patients during the endurance training intervention. Overall capillary-to-fiber ratio increased in HD patients by 8.4% and in healthy controls by 6.4% during the endurance training intervention. Skeletal muscle mitochondria of HD patients are equally responsive to an endurance-training stimulus as in healthy controls. Endurance training is a safe and feasible option to enhance indices of energy metabolism in skeletal muscle of HD patients and may represent a potential therapeutic approach to delay the onset and/or progression of muscular dysfunction. ClinicalTrials.gov NCT01879267 . Registered May 24, 2012.

  2. Underlying role of mitochondrial mutagenesis in the pathogenesis of a disease and current approaches for translational research.

    Science.gov (United States)

    Paraskevaidi, Maria; Martin-Hirsch, Pierre L; Kyrgiou, Maria; Martin, Francis L

    2017-05-01

    Mitochondrial diseases have been extensively investigated over the last three decades, but many questions regarding their underlying aetiologies remain unanswered. Mitochondrial dysfunction is not only responsible for a range of neurological and myopathy diseases but also considered pivotal in a broader spectrum of common diseases such as epilepsy, autism and bipolar disorder. These disorders are a challenge to diagnose and treat, as their aetiology might be multifactorial. In this review, the focus is placed on potential mechanisms capable of introducing defects in mitochondria resulting in disease. Special attention is given to the influence of xenobiotics on mitochondria; environmental factors inducing mutations or epigenetic changes in the mitochondrial genome can alter its expression and impair the whole cell's functionality. Specifically, we suggest that environmental agents can cause damage in mitochondrial DNA and consequently lead to mutagenesis. Moreover, we describe current approaches for handling mitochondrial diseases, as well as available prenatal diagnostic tests, towards eliminating these maternally inherited diseases. Undoubtedly, more research is required, as current therapeutic approaches mostly employ palliative therapies rather than targeting primary mechanisms or prophylactic approaches. Much effort is needed into further unravelling the relationship between xenobiotics and mitochondria, as the extent of influence in mitochondrial pathogenesis is increasingly recognised. © The Author 2016. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Insulin increases phosphorylation of mitochondrial proteins in human skeletal muscle in vivo

    DEFF Research Database (Denmark)

    Zhao, Xiaolu; Bak, Steffen; Pedersen, Andreas James Thestrup

    2014-01-01

    There is increasing evidence that multiple proteins involved in key regulatory processes in mitochondria are phosphorylated in mammalian tissues. Insulin regulates glucose metabolism by phosphorylation-dependent signaling and has been shown to stimulate ATP synthesis in human skeletal muscle. Here......, we investigated the effect of insulin on the phosphorylation of mitochondrial proteins in human skeletal muscle in vivo. Using a combination of TiO2 phosphopeptide-enrichment, HILIC fractionation, and LC−MS/MS, we compared the phosphoproteomes of isolated mitochondria from skeletal muscle samples...... obtained from healthy individuals before and after 4 h of insulin infusion. In total, we identified 207 phosphorylation sites in 95 mitochondrial proteins. Of these phosphorylation sites, 45% were identified in both basal and insulin-stimulated samples. Insulin caused a 2-fold increase in the number...

  4. Leber Hereditary Optic Neuropathy: A Mitochondrial Disease Unique in Many Ways.

    Science.gov (United States)

    Bi, Rui; Logan, Ian; Yao, Yong-Gang

    2017-01-01

    Leber hereditary optic neuropathy (LHON) was the first mitochondrial disease to be identified as being caused by mutations in the mitochondrial DNA (mtDNA). This disease has been studied extensively in the past two decades, particularly in Brazilian, Chinese and European populations; and many primary mutations have been reported. However, the disease is enigmatic with many unique features, and there still are several important questions to be resolved. The incomplete penetrance, the male-biased disease expression and the prevalence in young adults all defy a proper explanation. It has been reported that the development of LHON is affected by the interaction between mtDNA mutations, mtDNA haplogroup background, nuclear genes, environmental factors and epigenetics. Furthermore, with the help of new animal models for LHON that have been created in recent years, we are continuing to learn more about the mechanism of this disease. The stage has now been reached at which there is a good understanding of both the genetic basis of the disease and its epidemiology, but just how the blindness that follows from the death of cells in the optic nerve can be prevented remains to be a pharmacological challenge. In this chapter, we summarize the progress that has been made in various recent studies on LHON, focusing on the molecular pathogenic mechanisms, clinical features, biochemical effects, the pharmacology and its treatment.

  5. Superresolution Imaging of Human Cytomegalovirus vMIA Localization in Sub-Mitochondrial Compartments

    Science.gov (United States)

    Bhuvanendran, Shivaprasad; Salka, Kyle; Rainey, Kristin; Sreetama, Sen Chandra; Williams, Elizabeth; Leeker, Margretha; Prasad, Vidhya; Boyd, Jonathan; Patterson, George H.; Jaiswal, Jyoti K.; Colberg-Poley, Anamaris M.

    2014-01-01

    The human cytomegalovirus (HCMV) viral mitochondria-localized inhibitor of apoptosis (vMIA) protein, traffics to mitochondria-associated membranes (MAM), where the endoplasmic reticulum (ER) contacts the outer mitochondrial membrane (OMM). vMIA association with the MAM has not been visualized by imaging. Here, we have visualized this by using a combination of confocal and superresolution imaging. Deconvolution of confocal microscopy images shows vMIA localizes away from mitochondrial matrix at the Mitochondria-ER interface. By gated stimulated emission depletion (GSTED) imaging, we show that along this interface vMIA is distributed in clusters. Through multicolor, multifocal structured illumination microscopy (MSIM), we find vMIA clusters localize away from MitoTracker Red, indicating its OMM localization. GSTED and MSIM imaging show vMIA exists in clusters of ~100–150 nm, which is consistent with the cluster size determined by Photoactivated Localization Microscopy (PALM). With these diverse superresolution approaches, we have imaged the clustered distribution of vMIA at the OMM adjacent to the ER. Our findings directly compare the relative advantages of each of these superresolution imaging modalities for imaging components of the MAM and sub-mitochondrial compartments. These studies establish the ability of superresolution imaging to provide valuable insight into viral protein location, particularly in the sub-mitochondrial compartments, and into their clustered organization. PMID:24721787

  6. Superresolution Imaging of Human Cytomegalovirus vMIA Localization in Sub-Mitochondrial Compartments

    Directory of Open Access Journals (Sweden)

    Shivaprasad Bhuvanendran

    2014-04-01

    Full Text Available The human cytomegalovirus (HCMV viral mitochondria-localized inhibitor of apoptosis (vMIA protein, traffics to mitochondria-associated membranes (MAM, where the endoplasmic reticulum (ER contacts the outer mitochondrial membrane (OMM. vMIA association with the MAM has not been visualized by imaging. Here, we have visualized this by using a combination of confocal and superresolution imaging. Deconvolution of confocal microscopy images shows vMIA localizes away from mitochondrial matrix at the Mitochondria-ER interface. By gated stimulated emission depletion (GSTED imaging, we show that along this interface vMIA is distributed in clusters. Through multicolor, multifocal structured illumination microscopy (MSIM, we find vMIA clusters localize away from MitoTracker Red, indicating its OMM localization. GSTED and MSIM imaging show vMIA exists in clusters of ~100–150 nm, which is consistent with the cluster size determined by Photoactivated Localization Microscopy (PALM. With these diverse superresolution approaches, we have imaged the clustered distribution of vMIA at the OMM adjacent to the ER. Our findings directly compare the relative advantages of each of these superresolution imaging modalities for imaging components of the MAM and sub-mitochondrial compartments. These studies establish the ability of superresolution imaging to provide valuable insight into viral protein location, particularly in the sub-mitochondrial compartments, and into their clustered organization.

  7. Successful enrichment and recovery of whole mitochondrial genomes from ancient human dental calculus.

    Science.gov (United States)

    Ozga, Andrew T; Nieves-Colón, Maria A; Honap, Tanvi P; Sankaranarayanan, Krithivasan; Hofman, Courtney A; Milner, George R; Lewis, Cecil M; Stone, Anne C; Warinner, Christina

    2016-06-01

    Archaeological dental calculus is a rich source of host-associated biomolecules. Importantly, however, dental calculus is more accurately described as a calcified microbial biofilm than a host tissue. As such, concerns regarding destructive analysis of human remains may not apply as strongly to dental calculus, opening the possibility of obtaining human health and ancestry information from dental calculus in cases where destructive analysis of conventional skeletal remains is not permitted. Here we investigate the preservation of human mitochondrial DNA (mtDNA) in archaeological dental calculus and its potential for full mitochondrial genome (mitogenome) reconstruction in maternal lineage ancestry analysis. Extracted DNA from six individuals at the 700-year-old Norris Farms #36 cemetery in Illinois was enriched for mtDNA using in-solution capture techniques, followed by Illumina high-throughput sequencing. Full mitogenomes (7-34×) were successfully reconstructed from dental calculus for all six individuals, including three individuals who had previously tested negative for DNA preservation in bone using conventional PCR techniques. Mitochondrial haplogroup assignments were consistent with previously published findings, and additional comparative analysis of paired dental calculus and dentine from two individuals yielded equivalent haplotype results. All dental calculus samples exhibited damage patterns consistent with ancient DNA, and mitochondrial sequences were estimated to be 92-100% endogenous. DNA polymerase choice was found to impact error rates in downstream sequence analysis, but these effects can be mitigated by greater sequencing depth. Dental calculus is a viable alternative source of human DNA that can be used to reconstruct full mitogenomes from archaeological remains. Am J Phys Anthropol 160:220-228, 2016. © 2016 The Authors American Journal of Physical Anthropology Published by Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  8. Successful enrichment and recovery of whole mitochondrial genomes from ancient human dental calculus

    Science.gov (United States)

    Ozga, Andrew T.; Nieves‐Colón, Maria A.; Honap, Tanvi P.; Sankaranarayanan, Krithivasan; Hofman, Courtney A.; Milner, George R.; Lewis, Cecil M.; Stone, Anne C.

    2016-01-01

    ABSTRACT Objectives Archaeological dental calculus is a rich source of host‐associated biomolecules. Importantly, however, dental calculus is more accurately described as a calcified microbial biofilm than a host tissue. As such, concerns regarding destructive analysis of human remains may not apply as strongly to dental calculus, opening the possibility of obtaining human health and ancestry information from dental calculus in cases where destructive analysis of conventional skeletal remains is not permitted. Here we investigate the preservation of human mitochondrial DNA (mtDNA) in archaeological dental calculus and its potential for full mitochondrial genome (mitogenome) reconstruction in maternal lineage ancestry analysis. Materials and Methods Extracted DNA from six individuals at the 700‐year‐old Norris Farms #36 cemetery in Illinois was enriched for mtDNA using in‐solution capture techniques, followed by Illumina high‐throughput sequencing. Results Full mitogenomes (7–34×) were successfully reconstructed from dental calculus for all six individuals, including three individuals who had previously tested negative for DNA preservation in bone using conventional PCR techniques. Mitochondrial haplogroup assignments were consistent with previously published findings, and additional comparative analysis of paired dental calculus and dentine from two individuals yielded equivalent haplotype results. All dental calculus samples exhibited damage patterns consistent with ancient DNA, and mitochondrial sequences were estimated to be 92–100% endogenous. DNA polymerase choice was found to impact error rates in downstream sequence analysis, but these effects can be mitigated by greater sequencing depth. Discussion Dental calculus is a viable alternative source of human DNA that can be used to reconstruct full mitogenomes from archaeological remains. Am J Phys Anthropol 160:220–228, 2016. © 2016 The Authors American Journal of Physical Anthropology

  9. Two mutations in mitochondrial ATP6 gene of ATP synthase, related to human cancer, affect ROS, calcium homeostasis and mitochondrial permeability transition in yeast.

    Science.gov (United States)

    Niedzwiecka, Katarzyna; Tisi, Renata; Penna, Sara; Lichocka, Malgorzata; Plochocka, Danuta; Kucharczyk, Roza

    2018-01-01

    The relevance of mitochondrial DNA (mtDNA) mutations in cancer process is still unknown. Since the mutagenesis of mitochondrial genome in mammals is not possible yet, we have exploited budding yeast S. cerevisiae as a model to study the effects of tumor-associated mutations in the mitochondrial MTATP6 gene, encoding subunit 6 of ATP synthase, on the energy metabolism. We previously reported that four mutations in this gene have a limited impact on the production of cellular energy. Here we show that two mutations, Atp6-P163S and Atp6-K90E (human MTATP6-P136S and MTATP6-K64E, found in prostate and thyroid cancer samples, respectively), increase sensitivity of yeast cells both to compounds inducing oxidative stress and to high concentrations of calcium ions in the medium, when Om45p, the component of porin complex in outer mitochondrial membrane (OM), was fused to GFP. In OM45-GFP background, these mutations affect the activation of yeast permeability transition pore (yPTP, also called YMUC, yeast mitochondrial unspecific channel) upon calcium induction. Moreover, we show that calcium addition to isolated mitochondria heavily induced the formation of ATP synthase dimers and oligomers, recently proposed to form the core of PTP, which was slower in the mutants. We show the genetic evidence for involvement of mitochondrial ATP synthase in calcium homeostasis and permeability transition in yeast. This paper is a first to show, although in yeast model organism, that mitochondrial ATP synthase mutations, which accumulate during carcinogenesis process, may be significant for cancer cell escape from apoptosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Parkinson’s Disease: A Complex Interplay of Mitochondrial DNA Alterations and Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Sarah Ciccone

    2013-01-01

    Full Text Available Parkinson’s disease (PD is one of the most common age-related neurodegenerative diseases. This pathology causes a significant loss of dopaminergic neurons in the Substantia Nigra. Several reports have claimed a role of defective nuclear and mitochondrial DNA repair pathways in PD etiology, in particular, of the Base Excision Repair (BER system. In addition, recent findings, related to PD progression, indicate that oxidative stress pathways involving c-Abl and GST could also be implicated in this pathology. This review focuses on recently described networks most likely involved in an integrated manner in the course of PD.

  11. Human Mitochondrial RNA Polymerase: Evaluation of the Single-Nucleotide-Addition Cycle on Synthetic RNA/DNA Scaffolds

    Science.gov (United States)

    Smidansky, Eric D.; Arnold, Jamie J.; Reynolds, Shelley L.; Cameron, Craig E.

    2013-01-01

    The human mitochondrial RNA polymerase (h-mtRNAP) serves as both the transcriptase for expression and the primase for replication of mitochondrial DNA. As such, the enzyme is of fundamental importance to cellular energy metabolism, and defects in its function may be related to human disease states. Here we describe in vitro analysis of the h-mtRNAP kinetic mechanism for single, correct nucleotide incorporation. This was made possible by the development of efficient methods for expression and purification of h-mtRNAP using a bacterial system and by utilization of assays that rely on simple, synthetic RNA/DNA scaffolds without the need for mitochondrial transcription accessory proteins. We find that h-mtRNAP accomplishes single-nucleotide incorporation by using the same core steps, including conformational change steps before and after chemistry, that are prototypical for most types of nucleic acid polymerases. The polymerase binds to scaffolds via a two-step mechanism consisting of a fast initial-encounter step followed by a much slower isomerization that leads to catalytic competence. A substantial solvent deuterium kinetic isotope effect was observed for the forward reaction, but none was detectable for the reverse reaction, suggesting that chemistry is at least partially rate-limiting in the forward direction but not in the reverse. h-mtRNAP appears to exercise much more stringent surveillance over base than over sugar in determining the correctness of a nucleotide. The utility of developing the robust in vitro assays described here and of establishing a baseline of kinetic performance for the wild-type enzyme is that biological questions concerning h-mtRNAP may now begin to be addressed. PMID:21548588

  12. Pathological mitochondrial copper overload in livers of Wilson's disease patients and related animal models.

    Science.gov (United States)

    Zischka, Hans; Lichtmannegger, Josef

    2014-05-01

    In Wilson's disease (WD) and related animal models, liver mitochondria are confronted with an increasing copper burden. Physiologically, the mitochondrial matrix may act as a dynamic copper buffer that efficiently distributes the metal to its copper-dependent enzymes. Mitochondria are the first responders in the event of an imbalanced copper homeostasis, as typical changes of their structure are among the earliest observable pathological features in WD. These changes are due to accumulating copper in the mitochondrial membranes and can be reversed by copper-chelating therapies. At the early stage, copper-dependent oxidative stress does not seem to occur. On the contrary, however, when copper is massively deposited in mitochondria, severe structural and respiratory impairments are observed upon disease progression. This provokes reactive oxygen species and consequently causes the mitochondrial membranes to disintegrate, which triggers hepatocyte death. Thus, in WD mitochondria are prime targets for copper, and the excessive copper burden causes their destruction, subsequently provoking tissue failure and death. © 2014 New York Academy of Sciences.

  13. Characterization of NIST human mitochondrial DNA SRM-2392 and SRM-2392-I standard reference materials by next generation sequencing.

    Science.gov (United States)

    Riman, Sarah; Kiesler, Kevin M; Borsuk, Lisa A; Vallone, Peter M

    2017-07-01

    Standard Reference Materials SRM 2392 and 2392-I are intended to provide quality control when amplifying and sequencing human mitochondrial genome sequences. The National Institute of Standards and Technology (NIST) offers these SRMs to laboratories performing DNA-based forensic human identification, molecular diagnosis of mitochondrial diseases, mutation detection, evolutionary anthropology, and genetic genealogy. The entire mtGenome (∼16569bp) of SRM 2392 and 2392-I have previously been characterized at NIST by Sanger sequencing. Herein, we used the sensitivity, specificity, and accuracy offered by next generation sequencing (NGS) to: (1) re-sequence the certified values of the SRM 2392 and 2392-I; (2) confirm Sanger data with a high coverage new sequencing technology; (3) detect lower level heteroplasmies (sequencing communities in the adoption of NGS methods. To obtain a consensus sequence for the SRMs as well as identify and control any bias, sequencing was performed using two NGS platforms and data was analyzed using different bioinformatics pipelines. Our results confirm five low level heteroplasmy sites that were not previously observed with Sanger sequencing: three sites in the GM09947A template in SRM 2392 and two sites in the HL-60 template in SRM 2392-I. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. The clinical, biochemical and genetic features associated with RMND1-related mitochondrial disease

    DEFF Research Database (Denmark)

    Ng, Yi Shiau; Alston, Charlotte L; Diodato, Daria

    2016-01-01

    BACKGROUND: Mutations in the RMND1 (Required for Meiotic Nuclear Division protein 1) gene have recently been linked to infantile onset mitochondrial disease characterised by multiple mitochondrial respiratory chain defects. METHODS: We summarised the clinical, biochemical and molecular genetic...... investigation of an international cohort of affected individuals with RMND1 mutations. In addition, we reviewed all the previously published cases to determine the genotype-phenotype correlates and performed survival analysis to identify prognostic factors. RESULTS: We identified 14 new cases from 11 pedigrees...... months, p=0.009). The neurological phenotype also appears milder in patients with renal involvement. CONCLUSIONS: The clinical phenotypes and prognosis associated with RMND1 mutations are more heterogeneous than that were initially described. Regular monitoring of kidney function is imperative...

  15. Frequency and phenotypic implications of mitochondrial DNA mutations in human squamous cell cancers of the head and neck.

    Science.gov (United States)

    Zhou, Shaoyu; Kachhap, Sushant; Sun, Wenyue; Wu, Guojun; Chuang, Alice; Poeta, Luana; Grumbine, Lawson; Mithani, Suhail K; Chatterjee, Aditi; Koch, Wayne; Westra, William H; Maitra, Anirban; Glazer, Chad; Carducci, Michael; Sidransky, David; McFate, Thomas; Verma, Ajay; Califano, Joseph A

    2007-05-01

    Mitochondrial genomic mutations are found in a variety of human cancers; however, the frequency of mitochondrial DNA (mtDNA) mutations in coding regions remains poorly defined, and the functional effects of mitochondrial mutations found in primary human cancers are not well described. Using MitoChip, we sequenced the whole mitochondrial genome in 83 head and neck squamous cell carcinomas. Forty-one of 83 (49%) tumors contained mtDNA mutations. Mutations occurred within noncoding (D-loop) and coding regions. A nonrandom distribution of mutations was found throughout the mitochondrial enzyme complex components. Sequencing of margins with dysplasia demonstrated an identical nonconservative mitochondrial mutation (A76T in ND4L) as the tumor, suggesting a role of mtDNA mutation in tumor progression. Analysis of p53 status showed that mtDNA mutations correlated positively with p53 mutations (P < 0.002). To characterize biological function of the mtDNA mutations, we cloned NADH dehydrogenase subunit 2 (ND2) mutants based on primary tumor mutations. Expression of the nuclear-transcribed, mitochondrial-targeted ND2 mutants resulted in increased anchorage-dependent and -independent growth, which was accompanied by increased reactive oxygen species production and an aerobic glycolytic metabolic phenotype with hypoxia-inducible factor (HIF)-1alpha induction that is reversible by ascorbate. Cancer-specific mitochondrial mutations may contribute to development of a malignant phenotype by direct genotoxic effects from increased reactive oxygen species production as well as induction of aerobic glycolysis and growth promotion.

  16. Linking Microbiota to Human Diseases

    DEFF Research Database (Denmark)

    Wu, Hao; Tremaroli, Valentina; Bäckhed, F

    2015-01-01

    The human gut microbiota encompasses a densely populated ecosystem that provides essential functions for host development, immune maturation, and metabolism. Alterations to the gut microbiota have been observed in numerous diseases, including human metabolic diseases such as obesity, type 2...... may disentangle some of the mechanistic details in the complex interactions of diet, microbiota, and host metabolism and may provide testable hypotheses for advancing our current understanding of human-microbiota interaction....... diabetes (T2D), and irritable bowel syndrome, and some animal experiments have suggested causality. However, few studies have validated causality in humans and the underlying mechanisms remain largely to be elucidated. We discuss how systems biology approaches combined with new experimental technologies...

  17. Compromised mitochondrial complex II in models of Machado-Joseph disease.

    Science.gov (United States)

    Laço, Mário N; Oliveira, Catarina R; Paulson, Henry L; Rego, A Cristina

    2012-02-01

    Machado-Joseph disease (MJD), also known as Spinocerebellar Ataxia type 3, is an inherited dominant autosomal neurodegenerative disorder. An expansion of Cytosine-Adenine-Guanine (CAG) repeats in the ATXN3 gene is translated as an expanded polyglutamine domain in the disease protein, ataxin-3. Selective neurodegeneration in MJD is evident in several subcortical brain regions including the cerebellum. Mitochondrial dysfunction has been proposed as a mechanism of neurodegeneration in polyglutamine disorders. In this study, we used different cell models and transgenic mice to assess the importance of mitochondria on cytotoxicity observed in MJD. Transiently transfected HEK cell lines with expanded (Q84) ataxin-3 exhibited a higher susceptibility to 3-nitropropionic acid (3-NP), an irreversible inhibitor of mitochondrial complex II. Increased susceptibility to 3-NP was also detected in stably transfected PC6-3 cells that inducibly express expanded (Q108) ataxin-3 in a tetracycline-regulated manner. Moreover, cerebellar granule cells from MJD transgenic mice were more sensitive to 3-NP inhibition than wild-type cerebellar neurons. PC6-3 (Q108) cells differentiated into a neuronal-like phenotype with nerve growth factor (NGF) exhibited a significant decrease in mitochondrial complex II activity. Mitochondria from MJD transgenic mouse model and lymphoblast cell lines derived from MJD patients also showed a trend toward reduced complex II activity. Our results suggest that mitochondrial complex II activity is moderately compromised in MJD, which may designate a common feature in polyglutamine toxicity. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. Mitochondrial Dysfunction and Oxidative Stress in the Pathogenesis of Alcohol and Obesity Induced Fatty Liver Diseases

    Science.gov (United States)

    Mantena, Sudheer K.; King, Adrienne L.; Andringa, Kelly K.; Eccleston, Heather B.; Bailey, Shannon M.

    2008-01-01

    Fatty liver disease associated with chronic alcohol consumption or obesity/type 2 diabetes has emerged as a serious public health problem. Steatosis, accumulation of triglyceride in hepatocytes, is now recognized as a critical “first-hit” in the pathogenesis of liver disease. It is proposed that steatosis “primes” the liver to progress to more severe liver pathologies when individuals are exposed to subsequent metabolic and/or environmental stressors or “second-hits”. Genetic risk factors can also influence the susceptibility and severity of fatty liver disease. Furthermore, oxidative stress, disrupted nitric oxide (NO) signaling, and mitochondrial dysfunctional are proposed to be key molecular events that accelerate or worsen steatosis and initiate progression to steatohepatitis and fibrosis. This review article will discuss the following topics regarding the pathobiology and molecular mechanisms responsible for fatty liver disease: 1) the “two-hit” or “multi-hit” hypothesis; 2) the role of mitochondrial bioenergetic defects and oxidant stress; 3) interplay between NO and mitochondria in fatty liver disease; 4) genetic risk factors and oxidative stress responsive genes; and 5) the feasibility of antioxidants for treatment. PMID:18242193

  19. Calorie restriction increases muscle mitochondrial biogenesis in healthy humans.

    OpenAIRE

    Civitarese, Anthony E.; Stacy Carling; Heilbronn, Leonie K.; Hulver, Mathew H; Barbara Ukropcova; Deutsch, Walter A.; Smith, Steven R.; Eric Ravussin

    2007-01-01

    Editors' Summary Background. Life expectancy (the average life span) greatly increased during the 20th century in most countries, largely due to improved hygiene, nutrition, and health care. One possible approach to further increase human life span is “caloric restriction.” A calorie-restricted diet provides all the nutrients necessary for a healthy life but minimizes the energy (calories) supplied in the diet. This type of diet increases the life span of mice and delays the onset of age-rela...

  20. Analysis of 953 human proteins from a mitochondrial HEK293 fraction by complexome profiling.

    Directory of Open Access Journals (Sweden)

    Hans J C T Wessels

    Full Text Available Complexome profiling is a novel technique which uses shotgun proteomics to establish protein migration profiles from fractionated blue native electrophoresis gels. Here we present a dataset of blue native electrophoresis migration profiles for 953 proteins by complexome profiling. By analysis of mitochondrial ribosomal complexes we demonstrate its potential to verify putative protein-protein interactions identified by affinity purification-mass spectrometry studies. Protein complexes were extracted in their native state from a HEK293 mitochondrial fraction and separated by blue native gel electrophoresis. Gel lanes were cut into gel slices of even size and analyzed by shotgun proteomics. Subsequently, the acquired protein migration profiles were analyzed for co-migration via hierarchical cluster analysis. This dataset holds great promise as a comprehensive resource for de novo identification of protein-protein interactions or to underpin and prioritize candidate protein interactions from other studies. To demonstrate the potential use of our dataset we focussed on the mitochondrial translation machinery. Our results show that mitoribosomal complexes can be analyzed by blue native gel electrophoresis, as at least four distinct complexes. Analysis of these complexes confirmed that 24 proteins that had previously been reported to co-purify with mitoribosomes indeed co-migrated with subunits of the mitochondrial ribosome. Co-migration of several proteins involved in biogenesis of inner mitochondrial membrane complexes together with mitoribosomal complexes suggested the possibility of co-translational assembly in human cells. Our data also highlighted a putative ribonucleotide complex that potentially contains MRPL10, MRPL12 and MRPL53 together with LRPPRC and SLIRP.

  1. Mitochondrial Abnormalities and Synaptic Loss Underlie Memory Deficits Seen in Mouse Models of Obesity and Alzheimer's Disease.

    Science.gov (United States)

    Martins, Isaura V A; Rivers-Auty, Jack; Allan, Stuart M; Lawrence, Catherine B

    2017-01-01

    Obesity is associated with impaired memory in humans, and obesity induced by high-fat diets leads to cognitive deficits in rodents and in mouse models of Alzheimer's disease (AD). However, it remains unclear how high-fat diets contribute to memory impairment. Therefore, we tested the effect of a high-fat diet on memory in male and female control non-transgenic (Non-Tg) and triple-transgenic AD (3xTgAD) mice and determined if a high-fat diet caused similar ultrastructural abnormalities to those observed in AD. Behavior was assessed in mice on control or high-fat diet at 4, 8, or 14 months of age and ultrastructural analysis at 8 months of age. A high-fat diet increased body weight, fat weight, and insulin levels with some differences in these metabolic responses observed between Non-Tg and 3xTgAD mice. In both sexes, high-fat feeding caused memory impairments in Non-Tg mice and accelerated memory deficits in 3xTgAD mice. In 3xTgAD mice, changes in hippocampal mitochondrial morphology were observed in capillaries and brain neuropil that were accompanied by a reduction in synapse number. A high-fat diet also caused mitochondria abnormalities and a reduction in synapse number in Non-Tg mice, but did not exacerbate the changes seen in 3xTgAD mice. Our data demonstrate that a high-fat diet affected memory in Non-Tg mice and produced similar impairments in mitochondrial morphology and synapse number comparable to those seen in AD mice, suggesting that the detrimental effects of a high-fat diet on memory might be due to changes in mitochondrial morphology leading to a reduction in synaptic number.

  2. Mitochondrial Genome Analyses Suggest Multiple Trichuris Species in Humans, Baboons, and Pigs from Different Geographical Regions.

    Directory of Open Access Journals (Sweden)

    Mohamed B F Hawash

    Full Text Available The whipworms Trichuris trichiura and Trichuris suis are two parasitic nematodes of humans and pigs, respectively. Although whipworms in human and non-human primates historically have been referred to as T. trichiura, recent reports suggest that several Trichuris spp. are found in primates.We sequenced and annotated complete mitochondrial genomes of Trichuris recovered from a human in Uganda, an olive baboon in the US, a hamadryas baboon in Denmark, and two pigs from Denmark and Uganda. Comparative analyses using other published mitochondrial genomes of Trichuris recovered from a human and a porcine host in China and from a françois' leaf-monkey (China were performed, including phylogenetic analyses and pairwise genetic and amino acid distances. Genetic and protein distances between human Trichuris in Uganda and China were high (~19% and 15%, respectively suggesting that they represented different species. Trichuris from the olive baboon in US was genetically related to human Trichuris in China, while the other from the hamadryas baboon in Denmark was nearly identical to human Trichuris from Uganda. Baboon-derived Trichuris was genetically distinct from Trichuris from françois' leaf monkey, suggesting multiple whipworm species circulating among non-human primates. The genetic and protein distances between pig Trichuris from Denmark and other regions were roughly 9% and 6%, respectively, while Chinese and Ugandan whipworms were more closely related.Our results indicate that Trichuris species infecting humans and pigs are phylogenetically distinct across geographical regions, which might have important implications for the implementation of suitable and effective control strategies in different regions. Moreover, we provide support for the hypothesis that Trichuris infecting primates represents a complex of cryptic species with some species being able to infect both humans and non-human primates.

  3. Mitochondrial Mutations in tRNAGlu and Cytochrome b Genes Associated with Iranian Congenial Heart Disease

    Directory of Open Access Journals (Sweden)

    Mehri Khatami

    2016-12-01

    Full Text Available Background: Distribution of mitochondrial oxidative energy metabolism is a characteristic of cardiomyocyte dysfunction and congenital familial and sporadic heart diseases. Several studies have indicated that mutations in mitochondrial DNA, particularly in tRNAs and MT-CYB coding for cytochrome B in complex III (CIII, were associated with cardiologic disorders. We hypothesized that mutations in these positions might play an important causal or modifying role in congenital heart defects. Congenital Heart Diseases (CHDs are the most common anomaly in newborns and the leading non-infectious cause of mortality in the first year of life. These defects are multifactorial complex diseases resulting from both genetic predisposition and environmental risk factors. Despite advances in molecular medicine, the genetic mechanism underlying mitochondrial genetic determinants of development of CHD has remained poorly understood. Objectives: The present study aimed to identify the association between mitochondrial mutations in tRNAGlu and Cytb genes and CHD in Iranian patients. Materials and Methods: In this case-control study, tRNAGlu and MT-CYB genes were analyzed in DNA isolated from peripheral blood of 84 Iranian pediatric patients with non-familial CHD and 72 controls for alterations. The cases and healthy controls were matched regarding age and gender. Results: A total of three nucleotide variations were detected by Polymerase Chain Reaction-Single-Strand Conformation Polymorphism (PCR-SSCP and sequencing. One of them was located in tRNAGlu (A14696T found in a child with tetralogy of fallot and ventricular septal defect, which was assessed as a pathogen mutation. The second mutation was a homoplasmic variant (m.14766C > T in cytb gene and was not detected in the healthy controls.This variant altered an amino acid (T7I with moderately interspecific amino acid conservation indicative of the functional importance of the residue. Finally, a homoplasmic

  4. A novel transferrin/TfR2-mediated mitochondrial iron transport system is disrupted in Parkinson's disease.

    Science.gov (United States)

    Mastroberardino, Pier Giorgio; Hoffman, Eric K; Horowitz, Maxx P; Betarbet, Ranjita; Taylor, Georgia; Cheng, Dongmei; Na, Hye Mee; Gutekunst, Claire-Anne; Gearing, Marla; Trojanowski, John Q; Anderson, Marjorie; Chu, Charleen T; Peng, Junmin; Greenamyre, J Timothy

    2009-06-01

    More than 80 years after iron accumulation was initially described in the substantia nigra (SN) of Parkinson's disease (PD) patients, the mechanisms responsible for this phenomenon are still unknown. Similarly, how iron is delivered to its major recipients in the cell - mitochondria and the respiratory complexes - has yet to be elucidated. Here, we report a novel transferrin/transferrin receptor 2 (Tf/TfR2)-mediated iron transport pathway in mitochondria of SN dopamine neurons. We found that TfR2 has a previously uncharacterized mitochondrial targeting sequence that is sufficient to import the protein into these organelles. Importantly, the Tf/TfR2 pathway can deliver Tf bound iron to mitochondria and to the respiratory complex I as well. The pathway is redox-sensitive and oxidation of Tf thiols to disulfides induces release from Tf of highly reactive ferrous iron, which contributes to free radical production. In the rotenone model of PD, Tf accumulates in dopamine neurons, with much of it accumulating in the mitochondria. This is associated with iron deposition in SN, similar to what occurs in PD. In the human SN, TfR2 is also found in mitochondria of dopamine neurons, and in PD there is a dramatic increase of oxidized Tf in SN. Thus, we have discovered a novel mitochondrial iron transport system that goes awry in PD, and which may provide a new target for therapeutic intervention.

  5. Rodent models for human diseases.

    Science.gov (United States)

    Vandamme, Thierry F

    2015-07-15

    One of the factors limiting the translation of knowledge from preclinical studies to the clinic has been the limitations of in vivo diseases models. Except in the case of highly controlled and regulated clinical trials, geneticists and scientists do not use humans for their experimental investigations because of the obvious risk to life. Instead, they use various animal, fungal, bacterial, and plant species as model organisms for their studies. Amongst these model organisms, rodent models are the most used due to the easiness for the experiments and the possibility to modify genetically these model animals. Nevertheless, due to the fact that animal models typically do not contract the same genetic diseases as people, so scientists must alter their genomes to induce human disease states and to know what kind of mutation causes the disease. In this brief review, we will discuss the interests of rodent models that have been developed to simulate human pathologies, focusing in models that employ xenografts and genetic modification. Within the framework of genetically engineered mouse (GEM) models, we will review some of the current genetic strategies for modeling diseases. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Diagnosis by whole exome sequencing of atypical infantile onset Alexander disease masquerading as a mitochondrial disorder.

    Science.gov (United States)

    Nishri, Daniella; Edvardson, Simon; Lev, Dorit; Leshinsky-Silver, Esther; Ben-Sira, Liat; Henneke, Marco; Lerman-Sagie, Tally; Blumkin, Lubov

    2014-07-01

    There are many similarities, both clinical and radiological, between mitochondrial leukoencephalopathies and Alexander disease, an astrogliopathy. Clinically, both can manifest with a myriad of symptoms and signs, arising from the neonatal period to adulthood. Radiologically, both can demonstrate white matter changes, signal abnormalities of basal ganglia or thalami, brainstem abnormalities and contrast enhancement of white matter structures. Magnetic resonance spectroscopy may reveal elevation of lactate in the abnormal white matter in Alexander disease making the distinction even more challenging. We present a child who was considered to have an infantile onset mitochondrial disorder due to a combination of neurological symptoms and signs (developmental regression, failure to thrive, episodic deterioration, abnormal eye movements, pyramidal and cerebellar signs), urinary excretion of 3-methyl-glutaconic acid and imaging findings (extensive white matter changes and cerebellar atrophy) with a normal head circumference. Whole exome sequence analysis was performed. The child was found to harbor the R416W mutation, one of the most prevalent mutations in the glial fibrillary acidic protein (GFAP) gene that causes Alexander disease. Alexander disease should be considered in the differential diagnosis of infantile leukoencephalopathy, even when no macrocephaly is present. Next generation sequencing is a useful aid in unraveling the molecular etiology of leukoencephalopathies. Copyright © 2014 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  7. Diagnostics and prevention of nuclear-encoded mitochondrial diseases in infants

    Directory of Open Access Journals (Sweden)

    E. A. Nikolaeva

    2014-01-01

    Full Text Available The paper analyses recent publications on the clinical manifestations and diagnosis of mitochondrial diseases caused by defects in nuclear genes. A scientific analysis included about 100 genes. According to the encoded protein and its function, the author has identified 9 gene groups that affect the processes of cellular bioenergy. By the time of their manifestation, the diseases were divided into groups: those of early childhood (including neonatality, childhood, adolescence, and adulthood. Attention is drawn to difficulties to identify some forms of the diseases in view of the clinical polymorphism of manifestations of mutations in individual genes and, at the same tone, many similarities between clinical symptom complexes caused by different enzyme and gene defects. There are additional criteria for the differential diagnosis of the diseases: 3-methylglutaconic aciduria, depletions and multiple depletions of mitochondrial DNA. It is concluded that it is necessary to more extensively introduce the whole-exome sequencing test that can reveal not only common, but also rare gene mutations in nuclear DNA. Gene defect identification permits medical genetic counselling and prevention of the spread of severe pathology in the family.

  8. Roles of sigma-1 receptors on mitochondrial functions relevant to neurodegenerative diseases.

    Science.gov (United States)

    Weng, Tzu-Yu; Tsai, Shang-Yi Anne; Su, Tsung-Ping

    2017-09-16

    The sigma-1 receptor (Sig-1R) is a chaperone that resides mainly at the mitochondrion-associated endoplasmic reticulum (ER) membrane (called the MAMs) and acts as a dynamic pluripotent modulator in living systems. At the MAM, the Sig-1R is known to play a role in regulating the Ca2+ signaling between ER and mitochondria and in maintaining the structural integrity of the MAM. The MAM serves as bridges between ER and mitochondria regulating multiple functions such as Ca2+ transfer, energy exchange, lipid synthesis and transports, and protein folding that are pivotal to cell survival and defense. Recently, emerging evidences indicate that the MAM is critical in maintaining neuronal homeostasis. Thus, given the specific localization of the Sig-1R at the MAM, we highlight and propose that the direct or indirect regulations of the Sig-1R on mitochondrial functions may relate to neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and amyotrophic lateral sclerosis (ALS). In addition, the promising use of Sig-1R ligands to rescue mitochondrial dysfunction-induced neurodegeneration is addressed.

  9. Clinical variability in neurohepatic syndrome due to combined mitochondrial DNA depletion and Gaucher disease

    Directory of Open Access Journals (Sweden)

    Julie Harvengt

    2014-01-01

    Full Text Available A 1-year-old girl born to consanguineous parents presented with unexplained liver failure, leading to transplantation at 19 months. Subsequent partial splenectomy for persistent cytopenia showed the presence of foamy cells, and Gaucher disease was confirmed by homozygosity for the p.Leu483Pro mutation in the GBA gene. She was treated by enzyme replacement therapy (ERT. Clinical follow-up showed mild developmental delay, strabismus, nystagmus and oculomotor apraxia. Biochemical studies revealed multiple respiratory chain deficiencies and a mosaic pattern of deficient complex IV immunostaining in liver and fibroblast. Molecular analysis identified a mtDNA depletion syndrome due to the homozygous p.Pro98Leu mutation in MPV17. A younger sister unaffected by mtDNA depletion, presented with pancytopenia and hepatosplenomegaly. ERT for Gaucher disease resulted in visceral normalization without any neurological symptom. A third sister, affected by both conditions, had marked developmental delay, strabismus and ophthalmoplegia but no liver cirrhosis. In conclusion, intrafamilal variability occurs in MPV17-related disease. The combined pathological effect of Gaucher and mitochondrial diseases can negatively impact neurological and liver functions and influence the outcome in consanguineous families. The immunocytochemical staining of OXPHOS protein in tissues and cultured cells is a powerful tool revealing mosaic pattern of deficiency pointing to mtDNA-related mitochondrial disorders.

  10. Genistein suppresses the mitochondrial apoptotic pathway in hippocampal neurons in rats with Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2016-01-01

    Full Text Available Genistein is effective against amyloid-β toxicity, but the underlying mechanisms are unclear. We hypothesized that genistein may protect neurons by inhibiting the mitochondrial apoptotic pathway, and thereby play a role in the prevention of Alzheimer's disease. A rat model of Alzheimer's disease was established by intraperitoneal injection of D-galactose and intracerebral injection of amyloid-β peptide (25–35. In the genistein treatment groups, a 7-day pretreatment with genistein (10, 30, 90 mg/kg was given prior to establishing Alzheimer's disease model, for 49 consecutive days. Terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling assay demonstrated a reduction in apoptosis in the hippocampus of rats treated with genistein. Western blot analysis showed that expression levels of capase-3, Bax and cytochrome c were decreased compared with the model group. Furthermore, immunohistochemical staining revealed reductions in cytochrome c and Bax immunoreactivity in these rats. Morris water maze revealed a substantial shortening of escape latency by genist-ein in Alzheimer's disease rats. These findings suggest that genistein decreases neuronal loss in the hippocampus, and improves learning and memory ability. The neuroprotective effects of genistein are associated with the inhibition of the mitochondrial apoptotic pathway, as shown by its ability to reduce levels of caspase-3, Bax and cytochrome c.

  11. Repeated static contractions increase mitochondrial vulnerability toward oxidative stress in human skeletal muscle

    DEFF Research Database (Denmark)

    Sahlin, Kent; Nielsen, Jens Steen; Mogensen, Martin

    2006-01-01

    +) kinetics in human muscle. Ten male subjects performed five bouts of static knee extension with 10-min rest in between. Each bout of RSC (target torque 66% of maximal voluntary contraction torque) was maintained to fatigue. Muscle biopsies were taken preexercise and 0.3 and 24 h postexercise from vastus......Repeated static contractions (RSC) induce large fluctuations in tissue oxygen tension and increase the generation of reactive oxygen species (ROS). This study investigated the effect of RSC on muscle contractility, mitochondrial respiratory function, and in vitro sarcoplasmic reticulum (SR) Ca(2......, decreased mitochondrial efficiency (phosphorylated ADP-to-oxygen consumed ratio), and increased noncoupled respiration (HPX/Con post- vs. preexercise). SR Ca(2+) uptake rate was lower 0.3 vs. 24 h postexercise, whereas SR Ca(2+) release rate was unchanged. RSC resulted in long-lasting changes in muscle...

  12. Next-generation sequencing of human mitochondrial reference genomes uncovers high heteroplasmy frequency.

    Directory of Open Access Journals (Sweden)

    Maria Ximena Sosa

    Full Text Available We describe methods for rapid sequencing of the entire human mitochondrial genome (mtgenome, which involve long-range PCR for specific amplification of the mtgenome, pyrosequencing, quantitative mapping of sequence reads to identify sequence variants and heteroplasmy, as well as de novo sequence assembly. These methods have been used to study 40 publicly available HapMap samples of European (CEU and African (YRI ancestry to demonstrate a sequencing error rate <5.63×10(-4, nucleotide diversity of 1.6×10(-3 for CEU and 3.7×10(-3 for YRI, patterns of sequence variation consistent with earlier studies, but a higher rate of heteroplasmy varying between 10% and 50%. These results demonstrate that next-generation sequencing technologies allow interrogation of the mitochondrial genome in greater depth than previously possible which may be of value in biology and medicine.

  13. 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

    satellite cells at early and late passage numbers. We show that cultured muscle satellite cells undergoing senescence express a reduced mitochondrial mass, decreased whole cell ATP level, normal to increased mitochondrial ATP production under ATP utilization, increased mitochondrial membrane potential......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...... and increased superoxide/mitochondrial mass and hydrogen peroxide/mitochondrial mass ratios. Moreover, the increased ROS production correlates with the corresponding mitochondrial ATP production. Thus, myotubes differentiated from human myoblasts undergoing senescence have a reduced mitochondrial content...

  14. MitoLSDB: a comprehensive resource to study genotype to phenotype correlations in human mitochondrial DNA variations.

    Directory of Open Access Journals (Sweden)

    Shamnamole K

    Full Text Available Human mitochondrial DNA (mtDNA encodes a set of 37 genes which are essential structural and functional components of the electron transport chain. Variations in these genes have been implicated in a broad spectrum of diseases and are extensively reported in literature and various databases. In this study, we describe MitoLSDB, an integrated platform to catalogue disease association studies on mtDNA (http://mitolsdb.igib.res.in. The main goal of MitoLSDB is to provide a central platform for direct submissions of novel variants that can be curated by the Mitochondrial Research Community. MitoLSDB provides access to standardized and annotated data from literature and databases encompassing information from 5231 individuals, 675 populations and 27 phenotypes. This platform is developed using the Leiden Open (source Variation Database (LOVD software. MitoLSDB houses information on all 37 genes in each population amounting to 132397 variants, 5147 unique variants. For each variant its genomic location as per the Revised Cambridge Reference Sequence, codon and amino acid change for variations in protein-coding regions, frequency, disease/phenotype, population, reference and remarks are also listed. MitoLSDB curators have also reported errors documented in literature which includes 94 phantom mutations, 10 NUMTs, six documentation errors and one artefactual recombination. MitoLSDB is the largest repository of mtDNA variants systematically standardized and presented using the LOVD platform. We believe that this is a good starting resource to curate mtDNA variants and will facilitate direct submissions enhancing data coverage, annotation in context of pathogenesis and quality control by ensuring non-redundancy in reporting novel disease associated variants.

  15. Hesperidin alleviates cognitive impairment, mitochondrial dysfunction and oxidative stress in a mouse model of Alzheimer's disease.

    Science.gov (United States)

    Wang, Dongmei; Liu, Ling; Zhu, Xiaoying; Wu, Wenlan; Wang, Yong

    2014-11-01

    The role of mitochondrial dysfunction and oxidative stress has been well-documented in Alzheimer's disease (AD). Bioflavonoids are being utilised as neuroprotectants in the treatment of various neurological disorders, including AD. Therefore, we conducted this current study in order to explore the effects of hesperidin (a flavanone glycoside) against amyloid-β (Aβ)-induced cognitive dysfunction, oxidative damage and mitochondrial dysfunction in mice. Three-month-old APPswe/PS1dE9 transgenic mice were randomly assigned to a vehicle group, two hesperidin (either 50 or 100 mg/kg per day) groups, or an Aricept (2.5 mg/kg per day) group. After 16 weeks of treatment, although there was no obvious change in Aβ deposition in the hesperidin-treated (100 mg/kg per day) group, however, we found that the administration of hesperidin (100 mg/kg per day) resulted in the reduction of learning and memory deficits, improved locomotor activity, and the increase of anti-oxidative defense and mitochondrial complex I-IV enzymes activities. Furthermore, Glycogen synthase kinase-3β (GSK-3β) phosphorylation significantly increased in the hesperidin-treated (100 mg/kg per day) group. Taken together, these findings suggest that a reduction in mitochondrial dysfunction through the inhibition of GSK-3β activity, coupled with an increase in anti-oxidative defense, may be one of the mechanisms by which hesperidin improves cognitive function in the APPswe/PS1dE9 transgenic mouse model of AD.

  16. A novel mitochondrial tRNAAla gene variant causes chronic progressive external ophthalmoplegia in a patient with Huntington disease

    Directory of Open Access Journals (Sweden)

    Massimiliano Filosto

    2016-03-01

    Mitochondrial involvement is an emerging key determinant in the pathogenesis of Huntington disease and it is well known that mutant huntingtin influences the mitochondrial respiratory complexes II and III. A synergist effect of the HTT and MTTA mutations on respiratory chain function may be hypothesized in our patient and should be regarded as a spur for further studies on the mtDNA/HTT reciprocal interactions.

  17. Failed upregulation of TFAM protein and mitochondrial DNA in oxidatively deficient fibers of chronic obstructive pulmonary disease locomotor muscle

    OpenAIRE

    Konokhova, Yana; Spendiff, Sally; Jagoe, R Thomas; Aare, Sudhakar; Kapchinsky, Sophia; MacMillan, Norah J.; Rozakis, Paul; Picard, Martin; Aubertin-Leheudre, Myl?ne; Pion, Charlotte H; Bourbeau, Jean; Hepple, Russell T.; Taivassalo, Tanja

    2016-01-01

    Background Low mitochondrial content and oxidative capacity are well-established features of locomotor muscle dysfunction, a prevalent and debilitating systemic occurrence in patients with chronic obstructive pulmonary disease (COPD). Although the exact cause is not firmly established, physical inactivity and oxidative stress are among the proposed underlying mechanisms. Here, we assess the impact of COPD pathophysiology on mitochondrial DNA (mtDNA) integrity, biogenesis, and cellular oxidati...

  18. 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.

  19. Investigating the Role of Mitochondrial Haplogroups in Genetic Predisposition to Meningococcal Disease

    Science.gov (United States)

    Salas, Antonio; Fachal, Laura; Marcos-Alonso, Sonia; Vega, Ana; Martinón-Torres, Federico

    2009-01-01

    Background and Aims Meningococcal disease remains one of the most important infectious causes of death in industrialized countries. The highly diverse clinical presentation and prognosis of Neisseria meningitidis infections are the result of complex host genetics and environmental interactions. We investigated whether mitochondrial genetic background contributes to meningococcal disease (MD) susceptibility. Methodology/Principal Findings Prospective controlled study was performed through a national research network on MD that includes 41 Spanish hospitals. Cases were 307 paediatric patients with confirmed MD, representing the largest series of MD patients analysed to date. Two independent sets of ethnicity-matched control samples (CG1 [N = 917]), and CG2 [N = 616]) were used for comparison. Cases and controls underwent mtDNA haplotyping of a selected set of 25 mtDNA SNPs (mtSNPs), some of them defining major European branches of the mtDNA phylogeny. In addition, 34 ancestry informative markers (AIMs) were genotyped in cases and CG2 in order to monitor potential hidden population stratification. Samples of known African, Native American and European ancestry (N = 711) were used as classification sets for the determination of ancestral membership of our MD patients. A total of 39 individuals were eliminated from the main statistical analyses (including fourteen gypsies) on the basis of either non-Spanish self-reported ancestry or the results of AIMs indicating a European membership lower than 95%. Association analysis of the remaining 268 cases against CG1 suggested an overrepresentation of the synonym mtSNP G11719A variant (Pearson's chi-square test; adjusted P-value = 0.0188; OR [95% CI] = 1.63 [1.22–2.18]). When cases were compared with CG2, the positive association could not be replicated. No positive association has been observed between haplogroup (hg) status of cases and CG1/CG2 and hg status of cases and several clinical variants

  20. Herpesviruses in human periodontal disease.

    Science.gov (United States)

    Contreras, A; Slots, J

    2000-02-01

    Recent studies have identified various herpesviruses in human periodontal disease. Epstein-Barr virus type 1 (EBV-1) infects periodontal B-lymphocytes and human cytomegalovirus (HCMV) infects periodontal monocytes/ macrophages and T-lymphocytes. EBV-1, HCMV and other herpesviruses are present more frequently in periodontitis lesions and acute necrotizing ulcerative gingivitis-lesions than in gingivitis or periodontally healthy sites. Reactivation of HCMV in periodontitis lesions tends to be associated with progressing periodontal disease. Herpesvirus-associated periodontitis lesions harbor elevated levels of periodontopathic bacteria, including Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Bacteriodes forsythus, Prevotella intermedia, Prevotella nigrescens and Treponema denticola. It may be that active periodontal herpesvirus infection impairs periodontal defenses, thereby permitting subgingival overgrowth of periodontopathic bacteria. Alteration between latent and active herpesvirus infection in the periodontium might lead to transient local immunosuppression and explain in part the episodic progressive nature of human periodontitis. Tissue tropism of herpesvirus infections might help explain the localized pattern of tissue destruction in periodontitis. Absence of herpesvirus infection or viral reactivation might explain why some individuals carry periodontopathic bacteria while still maintaining periodontal health. Further studies are warranted to delineate whether the proposed herpesvirus-periodontopathic bacteria model might account for some of the pathogenic features of human periodontal disease.

  1. Effect of insulin on human skeletal muscle mitochondrial ATP production, protein synthesis, and mRNA transcripts

    Science.gov (United States)

    Stump, Craig S.; Short, Kevin R.; Bigelow, Maureen L.; Schimke, Jill M.; Sreekumaran Nair, K.

    2003-06-01

    Mitochondria are the primary site of skeletal muscle fuel metabolism and ATP production. Although insulin is a major regulator of fuel metabolism, its effect on mitochondrial ATP production is not known. Here we report increases in vastus lateralis muscle mitochondrial ATP production capacity (32-42%) in healthy humans (P growth hormone. Increased ATP production occurred in association with increased mRNA levels from both mitochondrial (NADH dehydrogenase subunit IV) and nuclear [cytochrome c oxidase (COX) subunit IV] genes (164-180%) encoding mitochondrial proteins (P muscle mitochondrial protein synthesis, and COX and citrate synthase enzyme activities were increased by insulin (P muscle mitochondrial ATP production for people with type 2 diabetes mellitus, whereas matched nondiabetic controls increased 16-26% (P muscle along with synthesis of gene transcripts and mitochondrial protein in human subjects. Skeletal muscle of type 2 diabetic patients has a reduced capacity to increase ATP production with high insulin levels. cytochrome c oxidase | NADH dehydrogenase subunit IV | amino acids | citrate synthase

  2. Hypertrophic Cardiomyopathy due to Mitochondrial Disease: Prenatal Diagnosis, Management, and Outcome

    Directory of Open Access Journals (Sweden)

    Lutgardo García-Díaz

    2013-01-01

    Full Text Available A case of prenatally diagnosed fetal hypertrophic cardiomyopathy is reported. The mother was referred to our department at 37 weeks' gestation because of suspected congenital heart disease. Prenatal echocardiography showed biventricular hypertrophy and pericardial effusion, without additional abnormalities. Postnatal echocardiography confirmed prenatal diagnosis. Neonatal EKG showed biventricular hypertrophy and Wolff-Parkinson-White syndrome. Skeletal muscle biopsy was consistent with mitochondrial oxidative phosphorylation defect involving a combined defect of respiratory complexes I and IV. Echocardiographic followup during the first year of life showed progressive regression of hypertrophy and evolution to left ventricular myocardial noncompaction.

  3. Extra-ocular muscle MRI in genetically-defined mitochondrial disease

    Energy Technology Data Exchange (ETDEWEB)

    Pitceathly, Robert D.S.; Morrow, Jasper M.; Hanna, Michael G. [UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, MRC Centre for Neuromuscular Diseases, London (United Kingdom); Sinclair, Christopher D.J.; Yousry, Tarek A.; Thornton, John S. [UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, MRC Centre for Neuromuscular Diseases, London (United Kingdom); UCL Institute of Neurology, Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, London (United Kingdom); Woodward, Cathy; Sweeney, Mary G. [National Hospital for Neurology and Neurosurgery, Neurogenetics Unit, London (United Kingdom); Rahman, Shamima [UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, MRC Centre for Neuromuscular Diseases, London (United Kingdom); UCL Institute of Child Health, Mitochondrial Research Group, Clinical and Molecular Genetics Unit, London (United Kingdom); Plant, Gordon T.; Ali, Nadeem [National Hospital for Neurology and Neurosurgery, Department of Neuro-ophthalmology, London (United Kingdom); Moorfields Eye Hospital, Department of Neuro-ophthalmology, London (United Kingdom); Bremner, Fion [National Hospital for Neurology and Neurosurgery, Department of Neuro-ophthalmology, London (United Kingdom); Davagnanam, Indran [National Hospital for Neurology and Neurosurgery, The Lysholm Department of Neuroradiology, London (United Kingdom)

    2016-01-15

    Conventional and quantitative MRI was performed in patients with chronic progressive external ophthalmoplegia (CPEO), a common manifestation of mitochondrial disease, to characterise MRI findings in the extra-ocular muscles (EOMs) and investigate whether quantitative MRI provides clinically relevant measures of disease. Patients with CPEO due to single mitochondrial DNA deletions were compared with controls. Range of eye movement (ROEM) measurements, peri-orbital 3 T MRI T1-weighted (T1w) and short-tau-inversion-recovery (STIR) images, and T2 relaxation time maps were obtained. Blinded observers graded muscle atrophy and T1w/STIR hyperintensity. Cross-sectional areas and EOM mean T2s were recorded and correlated with clinical parameters. Nine patients and nine healthy controls were examined. Patients had reduced ROEM (patients 13.3 , controls 49.3 , p < 0.001), greater mean atrophy score and increased T1w hyperintensities. EOM mean cross-sectional area was 43 % of controls and mean T2s were prolonged (patients 75.6 ± 7.0 ms, controls 55.2 ± 4.1 ms, p < 0.001). ROEM correlated negatively with EOM T2 (rho = -0.89, p < 0.01), whilst cross-sectional area failed to correlate with any clinical measures. MRI demonstrates EOM atrophy, characteristic signal changes and prolonged T2 in CPEO. Correlation between elevated EOM T2 and ROEM impairment represents a potential measure of disease severity that warrants further evaluation. (orig.)

  4. Diagnostic value of blood coenzyme Qlo levels in children with mitochondrial diseases

    Directory of Open Access Journals (Sweden)

    E. A. Nikolaeva

    2015-01-01

    Full Text Available То establish the diagnostic value of a change in the indicator coenzyme Qlo, its blood levels were tested in 15 children with mitochondrial diseases (Group 1. A comparison group consisted of 13 children with neurodegenerative diseases (Group 2. A control group included 29 healthy children of the same age. In Group 1 patients, the mean coenzyme Qlo level (0,56+0,06 mcmol/1 did not differ from that in the control group. However, these patients had a considerably lower coenzyme Q10/cholesterol ratio (0,10+0,01; /K0,001. The patients in the older age subgroup were found to have a significantly lower coenzyme Qlo level, which seems to reflect the progressive nature of the abnormality. There was a trend for the coenzyme Q10/cholesterol ratio to decline with age. Group 2 children had higher blood coenzyme Qlo levels (1,53+0,23; /K0,001 than Group 1 and an increased Q10/cholesterol ratio (0,31+0,04; /K0,001. It is advisable to continue the investigation to provide a rationale for using low coenzyme values as an additional criterion for the differential diagnosis of mitochondrial diseases.

  5. Proteins aggregation and human diseases

    Science.gov (United States)

    Hu, Chin-Kun

    2015-04-01

    Many human diseases and the death of most supercentenarians are related to protein aggregation. Neurodegenerative diseases include Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), frontotemporallobar degeneration, etc. Such diseases are due to progressive loss of structure or function of neurons caused by protein aggregation. For example, AD is considered to be related to aggregation of Aβ40 (peptide with 40 amino acids) and Aβ42 (peptide with 42 amino acids) and HD is considered to be related to aggregation of polyQ (polyglutamine) peptides. In this paper, we briefly review our recent discovery of key factors for protein aggregation. We used a lattice model to study the aggregation rates of proteins and found that the probability for a protein sequence to appear in the conformation of the aggregated state can be used to determine the temperature at which proteins can aggregate most quickly. We used molecular dynamics and simple models of polymer chains to study relaxation and aggregation of proteins under various conditions and found that when the bending-angle dependent and torsion-angle dependent interactions are zero or very small, then protein chains tend to aggregate at lower temperatures. All atom models were used to identify a key peptide chain for the aggregation of insulin chains and to find that two polyQ chains prefer anti-parallel conformation. It is pointed out that in many cases, protein aggregation does not result from protein mis-folding. A potential drug from Chinese medicine was found for Alzheimer's disease.

  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. Association between a common mitochondrial DNA D-loop polycytosine variant and alteration of mitochondrial copy number in human peripheral blood cells.

    Science.gov (United States)

    Liou, C-W; Lin, T-K; Chen, J-B; Tiao, M-M; Weng, S-W; Chen, S-D; Chuang, Y-C; Chuang, J-H; Wang, P-W

    2010-11-01

    A T-to-C transition at mitochondrial DNA (mtDNA) nucleotide position 16189 can generate a variable length polycytosine tract (poly-C). This tract variance has been associated with disease. A suggested pathogenesis is that it interferes with the replication process of mtDNA, which in turn decreases the mtDNA copy number and generates disease. In this study, 837 healthy adults' blood samples were collected and determined for their mtDNA D-loop sequence. The mtDNA copy number in the leucocytes and serum levels of oxidative thiobarbituric acid reactive substance (TBARS) and antioxidative thiols were measured. All subjects were then categorised into three groups: wild type or variant mtDNA with presence of an interrupted/uninterrupted poly-C at 16180-16195 segment. A step-wise multiple linear regression analysis identified factors affecting expression of mtDNA copy number including TBARS, thiols, age, body mass index and the mtDNA poly-C variant. Subjects harbouring a variant uninterrupted poly-C showed lowest mean (SD) mtDNA copy number (330 (178)), whereas an increased copy number was noted in subjects harbouring variant, interrupted poly-C (420 (273)) in comparison with wild type (358 (215)). The difference between the three groups and between the uninterrupted poly-C and the composite data from the interrupted poly-C and wild type remained consistent after adjustment for TBARS, thiols, age and body mass index (p=0.001 and p=0.011, respectively). A trend for decreased mtDNA copy number in association with increased number of continuous cytosine within the 16180-16195 segment was noted (p(trend)16189 variant can cause alteration of mtDNA copy number in human blood cells.

  8. Lactate dehydrogenase is not a mitochondrial enzyme in human and mouse vastus lateralis muscle

    Science.gov (United States)

    Rasmussen, Hans N; van Hall, Gerrit; Rasmussen, Ulla F

    2002-01-01

    The presence of lactate dehydrogenase in skeletal muscle mitochondria was investigated to clarify whether lactate is a possible substrate for mitochondrial respiration. Mitochondria were prepared from 100 mg samples of human and mouse vastus lateralis muscle. All fractions from the preparation procedure were assayed for marker enzymes and lactate dehydrogenase (LDH). The mitochondrial fraction contained no LDH activity (detection limit ∼0.05 % of the tissue activity) and the distribution of LDH activity among the fractions paralleled that of pyruvate kinase, i.e. LDH was fractionated as a cytoplasmic enzyme. Respiratory experiments with the mitochondrial fraction also indicated the absence of LDH. Lactate did not cause respiration, nor did it affect the respiration of pyruvate + malate. The major part of the native cytochrome c was retained in the isolated mitochondria, which, furthermore, showed high specific rates of state 3 respiration. This excluded artificial loss from the mitochondria of all activity of a possible LDH. It was concluded that skeletal muscle mitochondria are devoid of LDH and unable to metabolize lactate. PMID:12042361

  9. A novel synthetic analog of Militarin, MA-1 induces mitochondrial dependent apoptosis by ROS generation in human lung cancer cells.

    Science.gov (United States)

    Yoon, Deok Hyo; Lim, Mi-Hee; Lee, Yu Ran; Sung, Gi-Ho; Lee, Tae-Ho; Jeon, Byeong Hwa; Cho, Jae Youl; Song, Won O; Park, Haeil; Choi, Sunga; Kim, Tae Woong

    2013-12-15

    A synthetic Militarin analog-1[(2R,3R,4R,5R)-1,6-bis(4-(2,4,4-trimethylpentan-2-yl)phenoxy) hexane-2,3,4,5-tetraol] is a novel derivative of constituents from Cordyceps militaris, which has been used to treat a variety of chronic diseases including inflammation, diabetes, hyperglycemia and cancers. Here, we report for the first time the synthesis of Militarin analog-1 (MA-1) and the apoptotic mechanism of MA-1 against human lung cancer cell lines. Treatment with MA-1 significantly inhibited the viability of 3 human lung cancer cell lines. The inhibition of viability and growth in MA-1-treated A549 cells with an IC50 of 5μM were mediated through apoptosis induction, as demonstrated by an increase in DNA fragmentation, sub-G0/G1-DNA fraction, nuclear condensation, and phosphatidylserine exposure. The apoptotic cell death caused mitochondrial membrane permeabilization through regulation of expression of the Bcl-2 family proteins, leading to cytochrome c release in a time-dependent manner. Subsequently, the final stage of apoptosis, activation of caspase-9/-3 and cleavage of poly (ADP ribose) polymerase, was induced. Furthermore, A549 lung cancer cells were more responsive to MA-1 than a bronchial epithelial cell line (BEAS-2B), involving the rapid generation of reactive oxygen species (ROS), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) activation. The pharmacological inhibition of ROS generation and JNK/p38 MAPK exhibited attenuated DNA fragmentation in MA-1-induced apoptosis. Oral administration of MA-1 also retarded growth of A549 orthotopic xenografts. In conclusion, the present study indicates that the new synthetic derivative MA-1 triggers mitochondrial apoptosis through ROS generation and regulation of MAPKs and may be a potent therapeutic agent against human lung cancer. © 2013.

  10. Posttranslational modifications and dysfunction of mitochondrial enzymes in human heart failure.

    Science.gov (United States)

    Sheeran, Freya L; Pepe, Salvatore

    2016-08-01

    Deficiency of energy supply is a major complication contributing to the syndrome of heart failure (HF). Because the concurrent activity profile of mitochondrial bioenergetic enzymes has not been studied collectively in human HF, our aim was to examine the mitochondrial enzyme defects in left ventricular myocardium obtained from explanted end-stage failing hearts. Compared with nonfailing donor hearts, activity rates of complexes I and IV and the Krebs cycle enzymes isocitrate dehydrogenase, malate dehydrogenase, and aconitase were lower in HF, as determined spectrophotometrically. However, activity rates of complexes II and III and citrate synthase did not differ significantly between the two groups. Protein expression, determined by Western blotting, did not differ between the groups, implying posttranslational perturbation. In the face of diminished total glutathione and coenzyme Q10 levels, oxidative modification was explored as an underlying cause of enzyme dysfunction. Of the three oxidative modifications measured, protein carbonylation was increased significantly by 31% in HF (P < 0.01; n = 18), whereas levels of 4-hydroxynonenal and protein nitration, although elevated, did not differ. Isolation of complexes I and IV and F1FoATP synthase by immunocapture revealed that proteins containing iron-sulphur or heme redox centers were targets of oxidative modification. Energy deficiency in end-stage failing human left ventricle involves impaired activity of key electron transport chain and Krebs cycle enzymes without altered expression of protein levels. Augmented oxidative modification of crucial enzyme subunit structures implicates dysfunction due to diminished capacity for management of mitochondrial reactive oxygen species, thus contributing further to reduced bioenergetics in human HF. Copyright © 2016 the American Physiological Society.

  11. PINK1 defect causes mitochondrial dysfunction, proteasomal deficit and alpha-synuclein aggregation in cell culture models of Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Wencheng Liu

    Full Text Available Mutations in PTEN induced kinase 1 (PINK1, a mitochondrial Ser/Thr kinase, cause an autosomal recessive form of Parkinson's disease (PD, PARK6. Here, we report that PINK1 exists as a dimer in mitochondrial protein complexes that co-migrate with respiratory chain complexes in sucrose gradients. PARK6 related mutations do not affect this dimerization and its associated complexes. Using in vitro cell culture systems, we found that mutant PINK1 or PINK1 knock-down caused deficits in mitochondrial respiration and ATP synthesis. Furthermore, proteasome function is impaired with a loss of PINK1. Importantly, these deficits are accompanied by increased alpha-synclein aggregation. Our results indicate that it will be important to delineate the relationship between mitochondrial functional deficits, proteasome dysfunction and alpha-synclein aggregation.

  12. [Alzheimer's disease and human memory].

    Science.gov (United States)

    Eustache, F; Giffard, B; Rauchs, G; Chételat, G; Piolino, P; Desgranges, B

    2006-10-01

    Memory disorders observed in Alzheimer's disease gave rise, from the eighties, to a detailed analysis into the framework of cognitive neuropsychology which aimed at describing the deficits of very specific processes. Beyond their clinical interest, these studies contributed to the modelisation of human memory thanks to the characterization of different memory systems and their relationships. The first part of this paper gives an overview of the memory deficits in Alzheimer's disease and insists on particular cognitive phenomena. Hence, several examples are developed in the domains of semantic memory (such as hyperpriming and hypopriming effects) and autobiographical memory. Recent results highlight the existence of severe autobiographical amnesia observed in all neurodegenerative diseases, though with contrasting profiles: Ribot's gradient in Alzheimer's disease (showing that remote memories are better preserved than recent ones), reverse gradient in semantic dementia and no clear gradient in the frontal variant of frontotemporal dementia. The second part of this article presents advances in cognitive neuroscience searching to disclose the cerebral substrates of these cognitive deficits in Alzheimer's disease. The studies using functional imaging techniques are the most informative regarding this problematic. While showing the dysfunctions of an extended network, they emphasize the selectivity of cerebral damages that are at the root of very specific cognitive dysfunctions, coming close in that way to the conceptions of cognitive neuropsychology. These neuroimaging studies unravel the existence of compensatory mechanisms, which until recently were clearly missing in the literature on neurodegenerative diseases. These different researches lead to a wide conception of human memory, not just limited to simple instrumental processes (encoding, storage, retrieval), but necessarily covering models of identity and continuity of the subject, which interact in a dynamic way

  13. Role of diffuse low-level heteroplasmy of mitochondrial DNA in Alzheimer’s disease neurodegeneration

    Directory of Open Access Journals (Sweden)

    Tiziana eCasoli

    2015-07-01

    Full Text Available Alzheimer’s disease (AD is the most common form of dementia in the elderly. The vast majority of cases are not linked to a known genetic defect and the molecular mechanisms underlying AD pathogenesis are still elusive. Evidence suggests that mitochondrial dysfunction is a prominent feature of the disease, and that mitochondrial DNA (mtDNA alterations may represent a possible starting point of the pathophysiological cascade. Although specific mtDNA alterations have been reported in AD patients both in brain and peripheral tissues, such as D-loop mutations, 4977-bp deletion and poly-C tract D310 cytosine insertion, a generalized subtle allelic shift has also been demonstrated. This shift is significant for a few nucleotide positions (nps, but it is also detectable for most nps, although at a lower level. As single allelic substitutions can unlikely be determinant, it is proposed that the combination of all of them could lead to a less efficient oxidative phosphorylation, thus influencing AD development and course.

  14. A role for human mitochondrial complex II in the production of reactive oxygen species in human skin

    Directory of Open Access Journals (Sweden)

    Alasdair Anderson

    2014-01-01

    Full Text Available The mitochondrial respiratory chain is a major generator of cellular oxidative stress, thought to be an underlying cause of the carcinogenic and ageing process in many tissues including skin. Previous studies of the relative contributions of the respiratory chain (RC complexes I, II and III towards production of reactive oxygen species (ROS have focussed on rat tissues and certainly not on human skin which is surprising as this tissue is regularly exposed to UVA in sunlight, a potent generator of cellular oxidative stress. In a novel approach we have used an array of established specific metabolic inhibitors and DHR123 fluorescence to study the relative roles of the mitochondrial RC complexes in cellular ROS production in 2 types of human skin cells. These include additional enhancement of ROS production by exposure to physiological levels of UVA. The effects within epidermal and dermal derived skin cells are compared to other tissue cell types as well as those harbouring a compromised mitochondrial status (Rho-zero A549. The results show that the complex II inhibitor, TTFA, was the only RC inhibitor to significantly increase UVA-induced ROS production in both skin cell types (P<0.05 suggesting that the role of human skin complex II in terms of influencing ROS production is more important than previously thought particularly in comparison to liver cells. Interestingly, two-fold greater maximal activity of complex II enzyme was observed in both skin cell types compared to liver (P<0.001. The activities of RC enzymes appear to decrease with increasing age and telomere length is correlated with ageing. Our study showed that the level of maximal complex II activity was higher in the MRC5/hTERT (human lung fibroblasts transfected with telomerase cells than the corresponding wild type cells (P=0.0012 which can be considered (in terms of telomerase activity as models of younger and older cells respectively.

  15. Mutations in the mitochondrial methionyl-tRNA synthetase cause a neurodegenerative phenotype in flies and a recessive ataxia (ARSAL in humans.

    Directory of Open Access Journals (Sweden)

    Vafa Bayat

    Full Text Available An increasing number of genes required for mitochondrial biogenesis, dynamics, or function have been found to be mutated in metabolic disorders and neurological diseases such as Leigh Syndrome. In a forward genetic screen to identify genes required for neuronal function and survival in Drosophila photoreceptor neurons, we have identified mutations in the mitochondrial methionyl-tRNA synthetase, Aats-met, the homologue of human MARS2. The fly mutants exhibit age-dependent degeneration of photoreceptors, shortened lifespan, and reduced cell proliferation in epithelial tissues. We further observed that these mutants display defects in oxidative phosphorylation, increased Reactive Oxygen Species (ROS, and an upregulated mitochondrial Unfolded Protein Response. With the aid of this knowledge, we identified MARS2 to be mutated in Autosomal Recessive Spastic Ataxia with Leukoencephalopathy (ARSAL patients. We uncovered complex rearrangements in the MARS2 gene in all ARSAL patients. Analysis of patient cells revealed decreased levels of MARS2 protein and a reduced rate of mitochondrial protein synthesis. Patient cells also exhibited reduced Complex I activity, increased ROS, and a slower cell proliferation rate, similar to Drosophila Aats-met mutants.

  16. SERCA pumps and human diseases.

    Science.gov (United States)

    Hovnanian, A

    2007-01-01

    Sarco(endo)plasmic reticulum (SER) Ca2+ ATPases represent a highly conserved family of Ca2+ pumps which actively transport Ca2+ from the cytosol to the SER against a large concentration gradient. In humans, 3 genes (ATP2A1-3) generate multiple isoforms (SERCAla,b, SERCA2a-c, SECA3a-f) by developmental or tissue-specific alternative splicing. These pumps differ by their regulatory and kinetic properties, allowing for optimized function in the tissue where they are expressed. They play a central role in calcium signalling through regenerating SER Ca2+ stores, maintaining appropriate Ca2+ levels in this organelle and shaping cytosolic and nuclear Ca2+ variations which govern cell response. Defects in ATP2A1 encoding SERCA1 cause recessive Brody myopathy, mutations in ATP2A2 coding for SERCA2 underlie a dominant skin disease, Darier disease and its clinical variants. SERCA2a expression is reduced in heart failure in human and in mice models. Gene-targeting studies in mouse confirmed the expected function of these isoforms in some cases, but also resulted in unexpected phenotypes: SERCA1 null mutants die from respiratory failure, SERCA2 heterozygous mutant mice develop skin cancer with age and SERCA3 null mice display no diabetes. These unique phenotypes have provided invaluable information on the role of these pumps in specific tissues and species, and have improved our understanding of Ca2+ regulated processes in muscles, the heart and the skin in human and in mice. Although the understanding of the pathogenesis of these diseases is still incomplete, these recent advances hold the promise of improved knowledge on the disease processes and the identification of new targets for therapeutic interventions.

  17. Insights into the Phosphoryl Transfer Mechanism of Human Ubiquitous Mitochondrial Creatine Kinase.

    Science.gov (United States)

    Li, Quanjie; Fan, Shuai; Li, Xiaoyu; Jin, Yuanyuan; He, Weiqing; Zhou, Jinming; Cen, Shan; Yang, ZhaoYong

    2016-12-02

    Human ubiquitous mitochondrial creatine kinase (uMtCK) is responsible for the regulation of cellular energy metabolism. To investigate the phosphoryl-transfer mechanism catalyzed by human uMtCK, in this work, molecular dynamic simulations of uMtCK∙ATP-Mg2+∙creatine complex and quantum mechanism calculations were performed to make clear the puzzle. The theoretical studies hereof revealed that human uMtCK utilizes a two-step dissociative mechanism, in which the E227 residue of uMtCK acts as the catalytic base to accept the creatine guanidinium proton. This catalytic role of E227 was further confirmed by our assay on the phosphatase activity. Moreover, the roles of active site residues in phosphoryl transfer reaction were also identified by site directed mutagenesis. This study reveals the structural basis of biochemical activity of uMtCK and gets insights into its phosphoryl transfer mechanism.

  18. Mitochondrial dynamics altered by oxidative stress in cancer.

    Science.gov (United States)

    Kim, Boyun; Song, Yong Sang

    2016-10-01

    Mitochondria as crucial organelles regulate cellular energy generation, calcium and redox homeostasis, and apoptosis. To perform the cellular functions effectively, mitochondria continuously change their structure and morphology through protein machineries controlling fission and fusion process (mitochondrial dynamics). Traditionally, many researches had focused on the interaction of mitochondrial dynamics and apoptosis. However, recent studies are reporting the alteration of mitochondrial dynamics in human diseases including many types of cancers. Considering that cancers maintain a high level of reactive oxygen species (ROS), mitochondrial dynamics can be influenced by oxidative stress. In this review, we will discuss the alteration of mitochondrial dynamics by ROS and its effect on metastasis and chemoresistance in cancers.

  19. Mitochondrial GSH replenishment as a potential therapeutic approach for Niemann Pick type C disease

    Directory of Open Access Journals (Sweden)

    Sandra Torres

    2017-04-01

    Full Text Available Niemann Pick type C (NPC disease is a progressive lysosomal storage disorder caused by mutations in genes encoding NPC1/NPC2 proteins, characterized by neurological defects, hepatosplenomegaly and premature death. While the primary biochemical feature of NPC disease is the intracellular accumulation of cholesterol and gangliosides, predominantly in endolysosomes, mitochondrial cholesterol accumulation has also been reported. As accumulation of cholesterol in mitochondria is known to impair the transport of GSH into mitochondria, resulting in mitochondrial GSH (mGSH depletion, we investigated the impact of mGSH recovery in NPC disease. We show that GSH ethyl ester (GSH-EE, but not N-acetylcysteine (NAC, restored the mGSH pool in liver and brain of Npc1-/- mice and in fibroblasts from NPC patients, while both GSH-EE and NAC increased total GSH levels. GSH-EE but not NAC increased the median survival and maximal life span of Npc1-/- mice. Moreover, intraperitoneal therapy with GSH-EE protected against oxidative stress and oxidant-induced cell death, restored calbindin levels in cerebellar Purkinje cells and reversed locomotor impairment in Npc1-/- mice. High-resolution respirometry analyses revealed that GSH-EE improved oxidative phosphorylation, coupled respiration and maximal electron transfer in cerebellum of Npc1-/- mice. Lipidomic analyses showed that GSH-EE treatment had not effect in the profile of most sphingolipids in liver and brain, except for some particular species in brain of Npc1-/- mice. These findings indicate that the specific replenishment of mGSH may be a potential promising therapy for NPC disease, worth exploring alone or in combination with other options.

  20. The mitochondrial genomes of the human hookworms, Ancylostoma duodenale and Necator americanus (Nematoda: Secernentea).

    Science.gov (United States)

    Hu, Min; Chilton, Neil B; Gasser, Robin B

    2002-02-01

    The complete mitochondrial genome sequences were determined for two species of human hookworms, Ancylostoma duodenale (13,721 bp) and Necator americanus (13,604 bp). The circular hookworm genomes are amongst the smallest reported to date for any metazoan organism. Their relatively small size relates mainly to a reduced length in the AT-rich region. Both hookworm genomes encode 12 protein, two ribosomal RNA and 22 transfer RNA genes, but lack the ATP synthetase subunit 8 gene, which is consistent with three other species of Secernentea studied to date. All genes are transcribed in the same direction and have a nucleotide composition high in A and T, but low in G and C. The AT bias had a significant effect on both the codon usage pattern and amino acid composition of proteins. For both hookworm species, genes were arranged in the same order as for Caenorhabditis elegans, except for the presence of a non-coding region between genes nad3 and nad5. In A. duodenale, this non-coding region is predicted to form a stem-and-loop structure which is not present in N. americanus. The mitochondrial genome structure for both hookworms differs from Ascaris suum only in the location of the AT-rich region, whereas there are substantial differences when compared with Onchocerca volvulus, including four gene or gene-block translocations and the positions of some transfer RNA genes and the AT-rich region. Based on genome organisation and amino acid sequence identity, A. duodenale and N. americanus were more closely related to C. elegans than to A. suum or O. volvulus (all secernentean nematodes), consistent with a previous phylogenetic study using ribosomal DNA sequence data. Determination of the complete mitochondrial genome sequences for two human hookworms (the first members of the order Strongylida ever sequenced) provides a foundation for studying the systematics, population genetics and ecology of these and other nematodes of socio-economic importance.

  1. Influence of erythrocyte oxygenation and intravascular ATP on resting and exercising skeletal muscle blood flow in humans with mitochondrial myopathy

    DEFF Research Database (Denmark)

    Jeppesen, Tina D; Vissing, John; González-Alonso, José

    2012-01-01

    Oxygen (O(2)) extraction is impaired in exercising skeletal muscle of humans with mutations of mitochondrial DNA (mtDNA), but the muscle hemodynamic response to exercise has never been directly investigated. This study sought to examine the extent to which human skeletal muscle perfusion can incr...

  2. Human antimicrobial peptide histatin 5 is a cell-penetrating peptide targeting mitochondrial ATP synthesis in Leishmania

    NARCIS (Netherlands)

    Luque-Ortega, R.J.; van 't Hof, W.; Veerman, E.C.I.; Saugar, J.M.; Rivas, L.

    2008-01-01

    Histatin 5 (Hst5) is a human salivary antimicrobial peptide that targets fungal mitochondria. In the human parasitic protozoa Leishmania, the mitochondrial ATP production is essential, as it lacks the bioenergetic switch between glycolysis and oxidative phosphorylation described in some yeasts. On

  3. Harnessing the Power of Integrated Mitochondrial Biology and Physiology: A Special Report on the NHLBI Mitochondria in Heart Diseases Initiative.

    Science.gov (United States)

    Ping, Peipei; Gustafsson, Åsa B; Bers, Don M; Blatter, Lothar A; Cai, Hua; Jahangir, Arshad; Kelly, Daniel; Muoio, Deborah; O'Rourke, Brian; Rabinovitch, Peter; Trayanova, Natalia; Van Eyk, Jennifer; Weiss, James N; Wong, Renee; Schwartz Longacre, Lisa

    2015-07-17

    Mitochondrial biology is the sum of diverse phenomena from molecular profiles to physiological functions. A mechanistic understanding of mitochondria in disease development, and hence the future prospect of clinical translations, relies on a systems-level integration of expertise from multiple fields of investigation. Upon the successful conclusion of a recent National Institutes of Health, National Heart, Lung, and Blood Institute initiative on integrative mitochondrial biology in cardiovascular diseases, we reflect on the accomplishments made possible by this unique interdisciplinary collaboration effort and exciting new fronts on the study of these remarkable organelles. © 2015 American Heart Association, Inc.

  4. Adaptation of hepatic mitochondrial function in humans with non-alcoholic fatty liver is lost in steatohepatitis.

    Science.gov (United States)

    Koliaki, Chrysi; Szendroedi, Julia; Kaul, Kirti; Jelenik, Tomas; Nowotny, Peter; Jankowiak, Frank; Herder, Christian; Carstensen, Maren; Krausch, Markus; Knoefel, Wolfram Trudo; Schlensak, Matthias; Roden, Michael

    2015-05-05

    The association of hepatic mitochondrial function with insulin resistance and non-alcoholic fatty liver (NAFL) or steatohepatitis (NASH) remains unclear. This study applied high-resolution respirometry to directly quantify mitochondrial respiration in liver biopsies of obese insulin-resistant humans without (n = 18) or with (n = 16) histologically proven NAFL or with NASH (n = 7) compared to lean individuals (n = 12). Despite similar mitochondrial content, obese humans with or without NAFL had 4.3- to 5.0-fold higher maximal respiration rates in isolated mitochondria than lean persons. NASH patients featured higher mitochondrial mass, but 31%-40% lower maximal respiration, which associated with greater hepatic insulin resistance, mitochondrial uncoupling, and leaking activity. In NASH, augmented hepatic oxidative stress (H2O2, lipid peroxides) and oxidative DNA damage (8-OH-deoxyguanosine) was paralleled by reduced anti-oxidant defense capacity and increased inflammatory response. These data suggest adaptation of the liver ("hepatic mitochondrial flexibility") at early stages of obesity-related insulin resistance, which is subsequently lost in NASH. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Mitochondrial permeability transition increases reactive oxygen species production and induces DNA fragmentation in human spermatozoa.

    Science.gov (United States)

    Treulen, Favián; Uribe, Pamela; Boguen, Rodrigo; Villegas, Juana V

    2015-04-01

    Does mitochondrial permeability transition (MPT) induced by calcium overload cause reactive oxygen species (ROS) production and DNA fragmentation in human spermatozoa? Studies conducted in vitro suggest that in human spermatozoa, MPT occurs in response to intracellular calcium increase and is associated with mitochondrial membrane potential (ΔΨm) dissipation, increased ROS production and DNA fragmentation. Oxidative stress is a major cause of defective sperm function in male infertility. By opening calcium-dependent pores in the inner mitochondrial membrane (IMM), MPT causes, among other things, increased ROS production and ΔΨm dissipation in somatic cells. MPT as a mechanism for generating oxidative stress and DNA fragmentation in human spermatozoa has not been studied. Human sperm were exposed to ionomycin for 1.5 h (n = 8) followed by analysis of sperm IMM permeability, ΔΨm, ROS production and DNA fragmentation. To evaluate the MPT in sperm cells, the calcein-AM and cobalt chloride method was used. The ΔΨm was evaluated by JC-1 staining, intracellular ROS production was evaluated with dihydroethidium and DNA fragmentation was evaluated by a modified TUNEL assay. Measurements were performed by fluorescence microscopy, confocal laser microscopy and flow cytometry. Decreased calcein fluorescence after treatment with ionomycin (P fragmentation. ROS production occurred prior to the decrease in ΔΨm. The study was carried out in vitro using motile sperm from healthy donors; tests on sperm from infertile patients were not carried out. We propose that the MPT, due to pores opening in sperm IMM, is an important mechanism of increased ROS and DNA fragmentation. Therefore, agents that modulate the opening of these pores might contribute to the prevention of damage by oxidative stress in human spermatozoa. This study was funded by grant DI12-0102 from the Universidad de La Frontera (J.V.V.) and a doctoral scholarship from CONICYT Chile (F.T.). The authors disclose

  6. Reflex sympathetic dystrophy: complex regional pain syndrome type I in children with mitochondrial disease and maternal inheritance.

    Science.gov (United States)

    Higashimoto, T; Baldwin, E E; Gold, J I; Boles, R G

    2008-05-01

    Complex regional pain syndrome type I (CRPS-I), previously known as reflex sympathetic dystrophy (RSD), is an idiopathic condition characterised by localised, abnormally intense and prolonged pain, allodynia and autonomic nervous system changes (ie, swelling, skin colour and temperature changes and altered perspiration) that usually appear following a "noxious" trigger such as trauma or surgery. The objective of this report is to demonstrate that children with CRPS-I can have additional dysautonomic conditions secondary to an underlying maternally inherited mitochondrial disease, an association not previously published. Medical records of about 500 patients seen by one paediatric metabolic geneticist were reviewed to identify children meeting established CRPS diagnostic criteria. CRPS-I was present in eight children in seven families, each of which also had additional functional/dysautonomic conditions, the most common (> or = 4 cases per condition) being gastrointestinal dysmotility, migraine, cyclic vomiting and chronic fatigue. All seven probands studied met Nijmegen (2002) diagnostic criteria for definite mitochondrial disease on the basis of the clinical signs and symptoms and biochemical analyses. Six of the seven families met our pedigree-based criteria for probable maternal inheritance. In one tertiary-care paediatric genetics practice, children meeting the CRPS-I diagnostic criteria frequently had additional autonomic-related conditions secondary to maternally inherited mitochondrial disease, suggesting that mitochondrial DNA sequence variants can predispose children towards the development of CRPS-I and other dysautonomias. CRPS-I should be considered in patients with mitochondrial disease who complain of idiopathic pain. Maternally inherited mitochondrial disease may not be a rare cause of CRPS-I, especially in children who present with other manifestations of dysautonomia.

  7. Cholesterol can modulate mitochondrial aquaporin-8 expression in human hepatic cells.

    Science.gov (United States)

    Danielli, Mauro; Capiglioni, Alejo M; Marrone, Julieta; Calamita, Giuseppe; Marinelli, Raúl A

    2017-05-01

    Hepatocyte mitochondrial aquaporin-8 (mtAQP8) works as a multifunctional membrane channel protein that facilitates the uptake of ammonia for its detoxification to urea as well as the mitochondrial release of hydrogen peroxide. Since early oligonucleotide microarray studies in liver of cholesterol-fed mice showed an AQP8 downregulation, we tested whether alterations of cholesterol content per se modulate mtAQP8 expression in human hepatocyte-derived Huh-7 cells. Cholesterol loading with methyl-β-cyclodextrin (mβCD):cholesterol complexes downregulated the proteolytic activation of cholesterol-responsive sterol regulatory element-binding protein (SREBP) transcriptions factors 1 and 2, and the expression of the target gene 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR). Under such conditions, mtAQP8 mRNA and protein expressions were significantly reduced. In contrast, cholesterol depletion using mβCD alone increased SREBP-1 and 2 activation and upregulated HMGCR and mtAQP8 mRNA and protein expressions. The results suggest that cholesterol can regulate transcriptionally human hepatocyte mtAQP8 expression likely via SREBPs. The functional implications of our findings are discussed. © 2017 IUBMB Life, 69(5):341-346, 2017. © 2017 International Union of Biochemistry and Molecular Biology.

  8. The Plant Decapeptide OSIP108 Can Alleviate Mitochondrial Dysfunction Induced by Cisplatin in Human Cells

    Directory of Open Access Journals (Sweden)

    Pieter Spincemaille

    2014-09-01

    Full Text Available We investigated the effect of the Arabidopsis thaliana-derived decapeptide OSIP108 on human cell tolerance to the chemotherapeutic agent cisplatin (Cp, which induces apoptosis and mitochondrial dysfunction. We found that OSIP108 increases the tolerance of HepG2 cells to Cp and prevents Cp-induced changes in basic cellular metabolism. More specifically, we demonstrate that OSIP108 reduces Cp-induced inhibition of respiration, decreases glycolysis and prevents Cp-uptake in HepG2 cells. Apart from its protective action against Cp in human cells, OSIP108 also increases the yeast Saccharomyces cerevisiae tolerance to Cp. A limited yeast-based study of OSIP108 analogs showed that cyclization does not severely affect its activity, which was further confirmed in HepG2 cells. Furthermore, the similarity in the activity of the D-stereoisomer (mirror image form of OSIP108 with the L-stereoisomer suggests that its mode of action does not involve binding to a stereospecific receptor. In addition, as OSIP108 decreases Cp uptake in HepG2 cells and the anti-Cp activity of OSIP108 analogs without free cysteine is reduced, OSIP108 seems to protect against Cp-induced toxicity only partly via complexation. Taken together, our data indicate that OSIP108 and its cyclic derivatives can protect against Cp-induced toxicity and, thus, show potential as treatment options for mitochondrial dysfunction- and apoptosis-related conditions.

  9. Human Microbiota and Ophthalmic Disease.

    Science.gov (United States)

    Lu, Louise J; Liu, Ji

    2016-09-01

    The human ocular surface, consisting of the cornea and conjunctiva, is colonized by an expansive, diverse microbial community. Molecular-based methods, such as 16S rRNA sequencing, has allowed for more comprehensive and precise identification of the species composition of the ocular surface microbiota compared to traditional culture-based methods. Evidence suggests that the normal microbiota plays a protective immunological role in preventing the proliferation of pathogenic species and thus, alterations in the homeostatic microbiome may be linked to ophthalmic pathologies. Further investigation of the ocular surface microbiome, as well as the microbiome of other areas of the body such as the oral mucosa and gut, and their role in the pathophysiology of diseases is a significant, emerging field of research, and may someday enable the development of novel probiotic approaches for the treatment and prevention of ophthalmic diseases.

  10. Human Cytomegalovirus and Autoimmune Disease

    Science.gov (United States)

    2014-01-01

    Human cytomegalovirus (HCMV) represents a prototypic pathogenic member of the β-subgroup of the herpesvirus family. A range of HCMV features like its lytic replication in multiple tissues, the lifelong persistence through periods of latency and intermitting reactivation, the extraordinary large proteome, and extensive manipulation of adaptive and innate immunity make HCMV a high profile candidate for involvement in autoimmune disorders. We surveyed the available literature for reports on HCMV association with onset or exacerbation of autoimmune disease. A causative linkage between HCMV and systemic lupus erythematosus (SLE), systemic sclerosis (SSc), diabetes mellitus type 1, and rheumatoid arthritis (RA) is suggested by the literature. However, a clear association of HCMV seroprevalence and disease could not be established, leaving the question open whether HCMV could play a coresponsible role for onset of disease. For convincing conclusions population-based prospective studies must be performed in the future. Specific immunopathogenic mechanisms by which HCMV could contribute to the course of autoimmune disease have been suggested, for example, molecular mimicry by UL94 in SSc and UL83/pp65 in SLE patients, as well as aggravation of joint inflammation by induction and expansion of CD4+/CD28− T-cells in RA patients. Further studies are needed to validate these findings and to lay the grounds for targeted therapeutic intervention. PMID:24967373

  11. Human Cytomegalovirus and Autoimmune Disease

    Directory of Open Access Journals (Sweden)

    Anne Halenius

    2014-01-01

    Full Text Available Human cytomegalovirus (HCMV represents a prototypic pathogenic member of the β-subgroup of the herpesvirus family. A range of HCMV features like its lytic replication in multiple tissues, the lifelong persistence through periods of latency and intermitting reactivation, the extraordinary large proteome, and extensive manipulation of adaptive and innate immunity make HCMV a high profile candidate for involvement in autoimmune disorders. We surveyed the available literature for reports on HCMV association with onset or exacerbation of autoimmune disease. A causative linkage between HCMV and systemic lupus erythematosus (SLE, systemic sclerosis (SSc, diabetes mellitus type 1, and rheumatoid arthritis (RA is suggested by the literature. However, a clear association of HCMV seroprevalence and disease could not be established, leaving the question open whether HCMV could play a coresponsible role for onset of disease. For convincing conclusions population-based prospective studies must be performed in the future. Specific immunopathogenic mechanisms by which HCMV could contribute to the course of autoimmune disease have been suggested, for example, molecular mimicry by UL94 in SSc and UL83/pp65 in SLE patients, as well as aggravation of joint inflammation by induction and expansion of CD4+/CD28− T-cells in RA patients. Further studies are needed to validate these findings and to lay the grounds for targeted therapeutic intervention.

  12. Mitochondrial Alterations in Peripheral Mononuclear Blood Cells from Alzheimer’s Disease and Mild Cognitive Impairment Patients

    Directory of Open Access Journals (Sweden)

    A. Delbarba

    2016-01-01

    Full Text Available It is well recognized that mitochondrial dysfunction contributes to neurodegeneration occurring in Alzheimer’s disease (AD. However, evidences of mitochondrial defects in AD peripheral cells are still inconclusive. Here, some mitochondrial-encoded and nuclear-encoded proteins, involved in maintaining the correct mitochondria machine, were investigated in terms of protein expression and enzymatic activity in peripheral blood mononuclear cells (PBMCs isolated from AD and Mild Cognitive Impairment (MCI patients and healthy subjects. In addition mitochondrial DNA copy number was measured by real time PCR. We found some differences and some similarities between AD and MCI patients when compared with healthy subjects. For example, cytochrome C and cytochrome B were decreased in AD, while MCI showed only a statistical reduction of cytochrome C. On the other hand, both AD and MCI blood cells exhibited highly nitrated MnSOD, index of a prooxidant environment inside the mitochondria. TFAM, a regulator of mitochondrial genome replication and transcription, was decreased in both AD and MCI patients’ blood cells. Moreover also the mitochondrial DNA amount was reduced in PBMCs from both patient groups. In conclusion these data confirmed peripheral mitochondria impairment in AD and demonstrated that TFAM and mtDNA amount reduction could be two features of early events occurring in AD pathogenesis.

  13. 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

  14. Disruption of mitochondrial DNA replication in Drosophila increases mitochondrial fast axonal transport in vivo.

    Directory of Open Access Journals (Sweden)

    Rehan M Baqri

    Full Text Available Mutations in mitochondrial DNA polymerase (pol gamma cause several progressive human diseases including Parkinson's disease, Alper's syndrome, and progressive external ophthalmoplegia. At the cellular level, disruption of pol gamma leads to depletion of mtDNA, disrupts the mitochondrial respiratory chain, and increases susceptibility to oxidative stress. Although recent studies have intensified focus on the role of mtDNA in neuronal diseases, the changes that take place in mitochondrial biogenesis and mitochondrial axonal transport when mtDNA replication is disrupted are unknown. Using high-speed confocal microscopy, electron microscopy and biochemical approaches, we report that mutations in pol gamma deplete mtDNA levels and lead to an increase in mitochondrial density in Drosophila proximal nerves and muscles, without a noticeable increase in mitochondrial fragmentation. Furthermore, there is a rise in flux of bidirectional mitochondrial axonal transport, albeit with slower kinesin-based anterograde transport. In contrast, flux of synaptic vesicle precursors was modestly decreased in pol gamma-alpha mutants. Our data indicate that disruption of mtDNA replication does not hinder mitochondrial biogenesis, increases mitochondrial axonal transport, and raises the question of whether high levels of circulating mtDNA-deficient mitochondria are beneficial or deleterious in mtDNA diseases.

  15. MELAS: a new disease associated mitochondrial DNA mutation and evidence for further genetic heterogeneity

    OpenAIRE

    Hanna, M; Nelson, I; Morgan-Hughes, J; Wood, N

    1998-01-01

    OBJECTIVES—To define the molecular genetic basis of the MELAS phenotype in five patients without any known mutation of mitochondrial DNA.
METHODS—Systematic automated mitochondrial DNA sequencing of all mitochondrial transfer RNA and cytochrome c oxidase genes was undertaken in five patients who had the MELAS phenotype.
RESULTS— A novel heteroplasmic mitochondrial DNA mutation was identified in the transfer RNA gene for phenylalanine in one case (patient 3). This mutation wa...

  16. Enfermedades genéticas del ADN mitocondrial humano Genetic diseases of the mitochondrial DNA

    Directory of Open Access Journals (Sweden)

    Abelardo Solano

    2001-04-01

    Full Text Available Las enfermedades mitocondriales son un grupo de trastornos que están producidos por un fallo en el sistema de fosforilación oxidativa (sistema Oxphos, la ruta final del metabolismo energético mitocondrial, con la consiguiente deficiencia en la biosíntesis del trifosfato de adenosina (ATP, por sus siglas en inglés. Parte de los polipéptidos que componen este sistema están codificados en el ácido desoxirribonucleico (DNA mitocondrial y, en los últimos años, se han descrito mutaciones que se han asociado con síndromes clínicos bien definidos. Las características genéticas del DNA mitocondrial, herencia materna, poliplasmia y segregación mitótica, confieren a estas enfermedades propiedades muy particulares. Las manifestaciones clínicas de estas enfermedades son muy heterogéneas y afectan a distintos órganos y tejidos por lo que su correcto diagnóstico implica la obtención de datos clínicos, morfológicos, bioquímicos y genéticos. El texto completo en inglés de este artículo está disponible en: http://www.insp.mx/salud/index.htmlMitochondrial diseases are a group of disorders produced by defects in the oxidative phosphorylation system (Oxphos system, the final pathway of the mitochondrial energetic metabolism, resulting in a deficiency of the biosynthesis of ATP. Part of the polypeptide subunits involved in the Oxphos system are codified by the mitochondrial DNA. In the last years, mutations in this genetic system have been described and associated to well defined clinical syndromes. The clinical features of these disorders are very heterogeneous affecting, in most cases, to different organs and tissues and their correct diagnosis require precise clinical, morphological, biochemical and genetic data. The peculiar genetic characteristics of the mitochondrial DNA (maternal inheritance, polyplasmia and mitotic segregation give to these disorders very distinctive properties. The English version of this paper is available at

  17. Targeting Microglial KATP Channels to Treat Neurodegenerative Diseases: A Mitochondrial Issue

    Directory of Open Access Journals (Sweden)

    Manuel J. Rodríguez

    2013-01-01

    Full Text Available Neurodegeneration is a complex process involving different cell types and neurotransmitters. A common characteristic of neurodegenerative disorders is the occurrence of a neuroinflammatory reaction in which cellular processes involving glial cells, mainly microglia and astrocytes, are activated in response to neuronal death. Microglia do not constitute a unique cell population but rather present a range of phenotypes closely related to the evolution of neurodegeneration. In a dynamic equilibrium with the lesion microenvironment, microglia phenotypes cover from a proinflammatory activation state to a neurotrophic one directly involved in cell repair and extracellular matrix remodeling. At each moment, the microglial phenotype is likely to depend on the diversity of signals from the environment and of its response capacity. As a consequence, microglia present a high energy demand, for which the mitochondria activity determines the microglia participation in the neurodegenerative process. As such, modulation of microglia activity by controlling microglia mitochondrial activity constitutes an innovative approach to interfere in the neurodegenerative process. In this review, we discuss the mitochondrial KATP channel as a new target to control microglia activity, avoid its toxic phenotype, and facilitate a positive disease outcome.

  18. The mitochondrial T16189C polymorphism is associated with coronary artery disease in Middle European populations.

    Directory of Open Access Journals (Sweden)

    Edith E Mueller

    Full Text Available BACKGROUND: The pivotal role of mitochondria in energy production and free radical generation suggests that the mitochondrial genome could have an important influence on the expression of multifactorial age related diseases. Substitution of T to C at nucleotide position 16189 in the hypervariable D-loop of the control region (CR of mitochondrial DNA (mtDNA has attracted research interest because of its suspected association with various multifactorial diseases. The aim of the present study was to compare the frequency of this polymorphism in the CR of mtDNA in patients with coronary artery disease (CAD, n = 482 and type 2 diabetes mellitus (T2DM, n = 505 from two study centers, with healthy individuals (n = 1481 of Middle European descent in Austria. METHODOLOGY AND PRINCIPAL FINDINGS: CR polymorphisms and the nine major European haplogroups were identified by DNA sequencing and primer extension analysis, respectively. Frequencies and Odds Ratios for the association between cases and controls were calculated. Compared to healthy controls, the prevalence of T16189C was significantly higher in patients with CAD (11.8% vs 21.6%, as well as in patients with T2DM (11.8% vs 19.4%. The association of CAD, but not the one of T2DM, with T16189C remained highly significant after correction for age, sex and body mass index (BMI and was independent of the two study centers. CONCLUSIONS AND SIGNIFICANCE: Our results show for the first time a significant association of T16189C with CAD in a Middle European population. As reported in other studies, in patients with T2DM an association with T16189C in individuals of European decent remains questionable.

  19. The mitochondrial T16189C polymorphism is associated with coronary artery disease in Middle European populations.

    Science.gov (United States)

    Mueller, Edith E; Eder, Waltraud; Ebner, Sabine; Schwaiger, Eva; Santic, Danijela; Kreindl, Tanja; Stanger, Olaf; Paulweber, Bernhard; Iglseder, Bernhard; Oberkofler, Hannes; Maier, Richard; Mayr, Johannes A; Krempler, Franz; Weitgasser, Raimund; Patsch, Wolfgang; Sperl, Wolfgang; Kofler, Barbara

    2011-01-26

    The pivotal role of mitochondria in energy production and free radical generation suggests that the mitochondrial genome could have an important influence on the expression of multifactorial age related diseases. Substitution of T to C at nucleotide position 16189 in the hypervariable D-loop of the control region (CR) of mitochondrial DNA (mtDNA) has attracted research interest because of its suspected association with various multifactorial diseases. The aim of the present study was to compare the frequency of this polymorphism in the CR of mtDNA in patients with coronary artery disease (CAD, n = 482) and type 2 diabetes mellitus (T2DM, n = 505) from two study centers, with healthy individuals (n = 1481) of Middle European descent in Austria. CR polymorphisms and the nine major European haplogroups were identified by DNA sequencing and primer extension analysis, respectively. Frequencies and Odds Ratios for the association between cases and controls were calculated. Compared to healthy controls, the prevalence of T16189C was significantly higher in patients with CAD (11.8% vs 21.6%), as well as in patients with T2DM (11.8% vs 19.4%). The association of CAD, but not the one of T2DM, with T16189C remained highly significant after correction for age, sex and body mass index (BMI) and was independent of the two study centers. Our results show for the first time a significant association of T16189C with CAD in a Middle European population. As reported in other studies, in patients with T2DM an association with T16189C in individuals of European decent remains questionable.

  20. Mitochondrial disease: needs and problems of children, their parents and family. A systematic review and pilot study into the need for information of parents during the diagnostic phase.

    NARCIS (Netherlands)

    Noorda, G.; Hermans-Peters, M.; Smeitink, J.A.M.; Achterberg, T. van; Kemps, H.; Goverde, W.; Schoonhoven, L.

    2007-01-01

    OBJECTIVE: Firstly, this paper aims to systematically review the mitochondrial disease literature to identify studies assessing the needs and problems in the daily life of children with a mitochondrial disease and of their parents and family. The second aim is to provide more insight into the need

  1. The 6-min mastication test: a unique test to assess endurance of continuous chewing, normal values, reliability, reproducibility and usability in patients with mitochondrial disease

    NARCIS (Netherlands)

    Engel-Hoek, L. van den; Knuijt, S.; Gerven, M.H.J.C van; Lagarde, M.L.J.; Groothuis, J.T.; Groot, I.J.M. de; Janssen, M.C.

    2017-01-01

    In patients with mitochondrial disease, fatigue and muscle problems are the most common complaints. They also experience these complaints during mastication. To measure endurance of continuous mastication in patients with mitochondrial diseases, the 6-min mastication test (6MMT) was developed. This

  2. Secreted Human Adipose Leptin Decreases Mitochondrial Respiration in HCT116 Colon Cancer Cells

    Science.gov (United States)

    Yehuda-Shnaidman, Einav; Nimri, Lili; Tarnovscki, Tanya; Kirshtein, Boris; Rudich, Assaf; Schwartz, Betty

    2013-01-01

    Obesity is a key risk factor for the development of colon cancer; however, the endocrine/paracrine/metabolic networks mediating this connection are poorly understood. Here we hypothesize that obesity results in secreted products from adipose tissue that induce malignancy-related metabolic alterations in colon cancer cells. Human HCT116 colon cancer cells, were exposed to conditioned media from cultured human adipose tissue fragments of obese vs. non-obese subjects. Oxygen consumption rate (OCR, mostly mitochondrial respiration) and extracellular acidification rate (ECAR, mostly lactate production via glycolysis) were examined vis-à-vis cell viability and expression of related genes and proteins. Our results show that conditioned media from obese (vs. non-obese) subjects decreased basal (40%, prespiration and function in HCT116 colon cancer cells, an effect that is at least partly mediated by leptin. These results highlight a putative novel mechanism for obesity-associated risk of gastrointestinal malignancies, and suggest potential new therapeutic avenues. PMID:24073224

  3. Mitochondrial dynamics changes with age in an APPsw/PS1dE9 mouse model of Alzheimer's disease.

    Science.gov (United States)

    Xu, Lin-Lin; Shen, Yang; Wang, Xiao; Wei, Li-Fei; Wang, Ping; Yang, Hui; Wang, Cun-Fu; Xie, Zhao-Hong; Bi, Jian-Zhong

    2017-03-01

    Increasing research suggests that mitochondrial defects play a major role in Alzheimer's disease (AD) pathogenesis. We aimed to better understand changes in mitochondria with the development and progression of AD. We compared APPsw/PS1dE9 transgenic mice at 3, 6, 9, and 12 months old as an animal model of AD and age-matched C57BL/6 mice as controls. The learning ability and spatial memory ability of APPsw/PS1dE9 mice showed significant differences compared with controls until 9 and 12 months. Mitochondrial morphology was altered in hippocampus tissue of APPsw/PS1dE9 mice beginning from the third month. 'Medullary corpuscle', which is formed by the accumulation of a large amount of degenerative and fragmented mitochondria in neuropils, may be the characteristic change observed on electron microscopy at a late stage of AD. Moreover, levels of mitochondrial fusion proteins (optic atrophy 1 and mitofusin 2) and fission proteins (dynamin-related protein 1 and fission 1) were altered in transgenic mice compared with controls with progression of AD. We found increased levels of fission and fusion proteins in APP/PS1 mice at 3 months, indicating that the presence of abnormal mitochondrial dynamics may be events in early AD progression. Changes in mitochondrial preceded the onset of memory decline as measured by the modified Morris water maze test. Abnormal mitochondrial dynamics could be a marker for early diagnosis of AD and monitoring disease progression. Further research is needed to study the signaling pathways that govern mitochondrial fission/fusion in AD.

  4. Impairment of mitochondrial calcium handling in a mtSOD1 cell culture model of motoneuron disease

    Directory of Open Access Journals (Sweden)

    Zippelius Annette

    2009-06-01

    Full Text Available Abstract Background Amyotrophic lateral sclerosis (ALS is a fatal neurodegenerative disorder characterized by the selective loss of motor neurons (MN in the brain stem and spinal cord. Intracellular disruptions of cytosolic and mitochondrial calcium have been associated with selective MN degeneration, but the underlying mechanisms are not well understood. The present evidence supports a hypothesis that mitochondria are a target of mutant SOD1-mediated toxicity in familial amyotrophic lateral sclerosis (fALS and intracellular alterations of cytosolic and mitochondrial calcium might aggravate the course of this neurodegenerative disease. In this study, we used a fluorescence charged cool device (CCD imaging system to separate and simultaneously monitor cytosolic and mitochondrial calcium concentrations in individual cells in an established cellular model of ALS. Results To gain insights into the molecular mechanisms of SOD1G93A associated motor neuron disease, we simultaneously monitored cytosolic and mitochondrial calcium concentrations in individual cells. Voltage – dependent cytosolic Ca2+ elevations and mitochondria – controlled calcium release mechanisms were monitored after loading cells with fluorescent dyes fura-2 and rhod-2. Interestingly, comparable voltage-dependent cytosolic Ca2+ elevations in WT (SH-SY5YWT and G93A (SH-SY5YG93A expressing cells were observed. In contrast, mitochondrial intracellular Ca2+ release responses evoked by bath application of the mitochondrial toxin FCCP were significantly smaller in G93A expressing cells, suggesting impaired calcium stores. Pharmacological experiments further supported the concept that the presence of G93A severely disrupts mitochondrial Ca2+ regulation. Conclusion In this study, by fluorescence measurement of cytosolic calcium and using simultaneous [Ca2+]i and [Ca2+]mito measurements, we are able to separate and simultaneously monitor cytosolic and mitochondrial calcium concentrations

  5. Excess amino acid polymorphism in mitochondrial DNA: contrasts among genes from Drosophila, mice, and humans.

    Science.gov (United States)

    Rand, D M; Kann, L M

    1996-07-01

    Recent studies of mitochondrial DNA (mtDNA) variation in mammals and Drosophila have shown an excess of amino acid variation within species (replacement polymorphism) relative to the number of silent and replacement differences fixed between species. To examine further this pattern of nonneutral mtDNA evolution, we present sequence data for the ND3 and ND5 genes from 59 lines of Drosophila melanogaster and 29 lines of D. simulans. Of interest are the frequency spectra of silent and replacement polymorphisms, and potential variation among genes and taxa in the departures from neutral expectations. The Drosophila ND3 and ND5 data show no significant excess of replacement polymorphism using the McDonald-Kreitman test. These data are in contrast to significant departures from neutrality for the ND3 gene in mammals and other genes in Drosophila mtDNA (cytochrome b and ATPase 6). Pooled across genes, however, both Drosophila and human mtDNA show very significant excesses of amino acid polymorphism. Silent polymorphisms at ND5 show a significantly higher variance in frequency than replacement polymorphisms, and the latter show a significant skew toward low frequencies (Tajima's D = -1.954). These patterns are interpreted in light of the nearly neutral theory where mildly deleterious amino acid haplotypes are observed as ephemeral variants within species but do not contribute to divergence. The patterns of polymorphism and divergence at charge-altering amino acid sites are presented for the Drosophila ND5 gene to examine the evolution of functionally distinct mutations. Excess charge-altering polymorphism is observed at the carboxyl terminal and excess charge-altering divergence is detected at the amino terminal. While the mildly deleterious model fits as a net effect in the evolution of nonrecombining mitochondrial genomes, these data suggest that opposing evolutionary pressures may act on different regions of mitochondrial genes and genomes.

  6. Mitochondrial Modification Techniques and Ethical Issues.

    Science.gov (United States)

    Gómez-Tatay, Lucía; Hernández-Andreu, José M; Aznar, Justo

    2017-02-24

    Current strategies for preventing the transmission of mitochondrial disease to offspring include techniques known as mitochondrial replacement and mitochondrial gene editing. This technology has already been applied in humans on several occasions, and the first baby with donor mitochondria has already been born. However, these techniques raise several ethical concerns, among which is the fact that they entail genetic modification of the germline, as well as presenting safety problems in relation to a possible mismatch between the nuclear and mitochondrial DNA, maternal mitochondrial DNA carryover, and the "reversion" phenomenon. In this essay, we discuss these questions, highlighting the advantages of some techniques over others from an ethical point of view, and we conclude that none of these are ready to be safely applied in humans.

  7. Analysis of Mitochondrial Transfer in Direct Co-cultures of Human Monocyte-derived Macrophages (MDM) and Mesenchymal Stem Cells (MSC).

    Science.gov (United States)

    Jackson, Megan V; Krasnodembskaya, Anna D

    2017-05-05

    Mesenchymal stem/stromal cells (MSC) are adult stem cells which have been shown to improve survival, enhance bacterial clearance and alleviate inflammation in pre-clinical models of acute respiratory distress syndrome (ARDS) and sepsis. These diseases are characterised by uncontrolled inflammation often underpinned by bacterial infection. The mechanisms of MSC immunomodulatory effects are not fully understood yet. We sought to investigate MSC cell contact-dependent communication with alveolar macrophages (AM), professional phagocytes which play an important role in the lung inflammatory responses and anti-bacterial defence. With the use of a basic direct co-culture system, confocal microscopy and flow cytometry we visualised and effectively quantified MSC mitochondrial transfer to AM through tunnelling nanotubes (TNT). To model the human AM, primary monocytes were isolated from human donor blood and differentiated into macrophages (monocyte derived macrophages, MDM) in the presence of granulocyte macrophage colony-stimulating factor (GM-CSF), thus allowing adaptation of an AM-like phenotype (de Almeida et al., 2000; Guilliams et al., 2013). Human bone-marrow derived MSC, were labelled with mitochondria-specific fluorescent stain, washed extensively, seeded into the tissue culture plate with MDMs at the ratio of 1:20 (MSC/MDM) and co-cultured for 24 h. TNT formation and mitochondrial transfer were visualised by confocal microscopy and semi-quantified by flow cytometry. By using the method we described here we established that MSC use TNTs as the means to transfer mitochondria to macrophages. Further studies demonstrated that mitochondrial transfer enhances macrophage oxidative phosphorylation and phagocytosis. When TNT formation was blocked by cytochalasin B, MSC effect on macrophage phagocytosis was completely abrogated. This is the first study to demonstrate TNT-mediated mitochondrial transfer from MSC to innate immune cells.

  8. Structure of the Human Mitochondrial Ribosome Studied In Situ by Cryoelectron Tomography

    NARCIS (Netherlands)

    Englmeier, Robert; Pfeffer, Stefan; Förster, Friedrich

    2017-01-01

    Mitochondria maintain their own genome and its corresponding protein synthesis machine, the mitochondrial ribosome (mitoribosome). Mitoribosomes primarily synthesize highly hydrophobic proteins of the inner mitochondrial membrane. Recent studies revealed the complete structure of the isolated

  9. Dose-dependent Effects of mTOR Inhibition on Weight and Mitochondrial Disease in Mice

    Directory of Open Access Journals (Sweden)

    Simon C Johnson

    2015-07-01

    Full Text Available Rapamycin extends lifespan and attenuates age-related pathologies in mice when administered through diet at 14 parts per million (PPM. Recently, we reported that daily intraperitoneal injection of rapamycin at 8 mg/kg attenuates mitochondrial disease symptoms and progression in the Ndufs4 knockout mouse model of Leigh Syndrome. Although rapamycin is a widely used pharmaceutical agent dosage has not been rigorously examined and no dose-response profile has been established. Given these observations we sought to determine if increased doses of oral rapamycin would result in more robust impact on mTOR driven parameters. To test this hypothesis, we compared the effects of dietary rapamycin at doses ranging from 14 to 378 PPM on growth in control and Ndufs4 knockout mice and on health and survival in the Ndufs4 knockout model. High dose rapamycin was well tolerated, dramatically reduced growth, and overcame gender differences. The highest oral dose, approximately 27-times the dose shown to extend murine lifespan, increased survival in Ndufs4 knockout mice similarly to daily rapamycin injection without observable adverse effects. These findings have broad implications for the effective use of rapamycin in murine studies and for the translational potential of rapamycin in the treatment of mitochondrial disease. This data, further supported by a comparison of available literature, suggests that 14 PPM dietary rapamycin is a sub-optimal dose for targeting mTOR systemically in mice. Our findings suggest that the role of mTOR in mammalian biology may be broadly underestimated when determined through treatment with rapamycin at commonly used doses.

  10. Dysfunctional mitochondrial respiration in the striatum of the Huntington's disease transgenic R6/2 mouse model

    DEFF Research Database (Denmark)

    Aidt, Frederik Heurlin; Nielsen, Signe Marie Borch; Kanters, Jørgen

    2013-01-01

    Metabolic dysfunction and mitochondrial involvement are recognised as part of the pathology in Huntington's Disease (HD). Post-mortem examinations of the striatum from end-stage HD patients have shown a decrease in the in vitro activity of complexes II, III and IV of the electron transport system...

  11. Expression of a novel non-coding mitochondrial RNA in human proliferating cells

    Science.gov (United States)

    Villegas, Jaime; Burzio, Veronica; Villota, Claudio; Landerer, Eduardo; Martinez, Ronny; Santander, Marcela; Martinez, Rodrigo; Pinto, Rodrigo; Vera, María I.; Boccardo, Enrique; Villa, Luisa L.; Burzio, Luis O.

    2007-01-01

    Previously, we reported the presence in mouse cells of a mitochondrial RNA which contains an inverted repeat (IR) of 121 nucleotides (nt) covalently linked to the 5′ end of the mitochondrial 16S RNA (16S mtrRNA). Here, we report the structure of an equivalent transcript of 2374 nt which is over-expressed in human proliferating cells but not in resting cells. The transcript contains a hairpin structure comprising an IR of 815 nt linked to the 5′ end of the 16S mtrRNA and forming a long double-stranded structure or stem and a loop of 40 nt. The stem is resistant to RNase A and can be detected and isolated after digestion with the enzyme. This novel transcript is a non-coding RNA (ncRNA) and several evidences suggest that the transcript is synthesized in mitochondria. The expression of this transcript can be induced in resting lymphocytes stimulated with phytohaemagglutinin (PHA). Moreover, aphidicolin treatment of DU145 cells reversibly blocks proliferation and expression of the transcript. If the drug is removed, the cells re-assume proliferation and over-express the ncmtRNA. These results suggest that the expression of the ncmtRNA correlates with the replicative state of the cell and it may play a role in cell proliferation. PMID:17962305

  12. Characterization of human mitochondrial ferritin promoter: identification of transcription factors and evidences of epigenetic control

    Science.gov (United States)

    Guaraldo, Michela; Santambrogio, Paolo; Rovelli, Elisabetta; di Savino, Augusta; Saglio, Giuseppe; Cittaro, Davide; Roetto, Antonella; Levi, Sonia

    2016-09-01

    Mitochondrial ferritin (FtMt) is an iron storage protein belonging to the ferritin family but, unlike the cytosolic ferritin, it has an iron-unrelated restricted tissue expression. FtMt appears to be preferentially expressed in cell types characterized by high metabolic activity and oxygen consumption, suggesting a role in protecting mitochondria from iron-dependent oxidative damage. The human gene (FTMT) is intronless and its promoter region has not been described yet. To analyze the regulatory mechanisms controlling FTMT expression, we characterized the 5‧ flanking region upstream the transcriptional starting site of FTMT by in silico enquiry of sequences conservation, DNA deletion analysis, and ChIP assay. The data revealed a minimal promoter region and identified the presence of SP1, CREB and YY1 as positive regulators, and GATA2, FoxA1 and C/EBPβ as inhibitors of the transcriptional regulation. Furthermore, the FTMT transcription is increased by acetylating and de-methylating agent treatments in K562 and HeLa cells. These treatments up-regulate FtMt expression even in fibroblasts derived from a Friedreich ataxia patient, where it might exert a beneficial effect against mitochondrial oxidative damage. The expression of FTMT appears regulated by a complex mechanism involving epigenetic events and interplay between transcription factors.

  13. Laminarin Induces Apoptosis of Human Colon Cancer LOVO Cells through a Mitochondrial Pathway

    Directory of Open Access Journals (Sweden)

    He Zhang

    2012-08-01

    Full Text Available Many scientific studies have shown that laminarin has anti-tumor effects, but the anti-tumor mechanism was unclear. The purpose of this study was to investigate the effect of laminarin on the induction of apoptosis in human colon cancer LOVO cells and the molecular mechanism involved. LOVO cells were treated with different concentrations of laminarin at different times. Morphology observations were performed to determine the effects of laminarin on apoptosis of LOVO cells. Flow cytometry (FCM was used to detect the level of intracellular reactive oxygen species (ROS and pH. Laser scanning confocal microscope (LSCM was used to analyze intracellular calcium ion concentration, mitochondrion permeability transition pore (MPTP and mitochondrial membrane potential (MMP. Western blotd were performed to analyze the expressions of Cyt-C, Caspase-9 and -3. The results showed the apoptosis morphology, which showed cell protuberance, concentrated cytoplasm and apoptotic bodies, was obvious after 72 h treatment. Laminarin treatment for 24 h increased the intracellular level of ROS and Ca2+; decreased pH value; activated intracellular MPTP and decreased MMP in dose-dependent manners. It also induced the release of Cyt-C and the activation of Caspase-9 and -3. In conclusion, laminarin induces LOVO cell apoptosis through a mitochondrial pathway, suggesting that it could be a potent agent for cancer prevention and treatment.

  14. Frequent somatic transfer of mitochondrial DNA into the nuclear genome of human cancer cells

    NARCIS (Netherlands)

    Y.S. Ju (Young Seok); J.M.C. Tubio (Jose M.); W. Mifsud (William); B. Fu (Beiyuan); H. Davies (Helen); M. Ramakrishna (Manasa); Y. Li (Yilong); L.R. Yates (Lucy); G. Gundem (Gunes); P.S. Tarpey (Patrick); S. Behjati (Sam); E. Papaemmanuil (Elli); S. Martin (Sandra); A. Fullam (Anthony); M. Gerstung (Moritz); J. Nangalia (Jyoti); A.R. Green (Anthony R.); C. Caldas (Carlos); Å. Borg (Åke); A. Tutt (Andrew); M.T. Michael Lee (Ming Ta); L.J. van 't Veer (Laura); B.K.T. Tan (Benita K.T.); S.A.J.R. Aparicio (Samuel A. J.); P.N. Span (Paul); J.W.M. Martens (John W. M.); S. Knappskog (Stian); A. Vincent-Salomon (Anne); A.-L. Borresen-Dale (Anne-Lise); J. Eyfjord; A.M. Flanagan (Adrienne); C.S. Foster; D. Neal (David); C. Cooper (Colin); R. Eeles (Rosalind); S. Lakhani (Sunil); C. Desmedt (Christine); G. Thomas (Gilles); A.L. Richardson (Andrea); C.A. Purdie (Colin A.); A.M. Thompson (Alastair M.); U. McDermott (Ultan); F. Yang (Fengtang); S. Nik-Zainal (Serena); P.J. Campbell (Peter); M.R. Stratton (Michael)

    2015-01-01

    textabstractMitochondrial genomes are separated from the nuclear genome for most of the cell cycle by the nuclear double membrane, intervening cytoplasm, and the mitochondrial double membrane. Despite these physical barriers, we show that somatically acquired mitochondrial-nuclear genome fusion

  15. Ketamine induces toxicity in human neurons differentiated from embryonic stem cells via mitochondrial apoptosis pathway

    Science.gov (United States)

    Bosnjak, Zeljko J.; Yan, Yasheng; Canfield, Scott; Muravyeva, Maria Y.; Kikuchi, Chika; Wells, Clive; Corbett, John; Bai, Xiaowen

    2013-01-01

    Ketamine is widely used for anesthesia in pediatric patients. Growing evidence indicates that ketamine causes neurotoxicity in a variety of developing animal models. Our understanding of anesthesia neurotoxicity in humans is currently limited by difficulties in obtaining neurons and performing developmental toxicity studies in fetal and pediatric populations. It may be possible to overcome these challenges by obtaining neurons from human embryonic stem cells (hESCs) in vitro. hESCs are able to replicate indefinitely and differentiate into every cell type. In this study, we investigated the toxic effect of ketamine on neurons differentiated from hESCs. Two-week-old neurons were treated with different doses and durations of ketamine with or without the reactive oxygen species (ROS) scavenger, Trolox. Cell viability, ultrastructure, mitochondrial membrane potential (ΔΨm), cytochrome c distribution within cells, apoptosis, and ROS production were evaluated. Here we show that ketamine induced ultrastructural abnormalities and dose- and time-dependently caused cell death. In addition, ketamine decreased ΔΨm and increased cytochrome c release from mitochondria. Ketamine also increased ROS production and induced differential expression of oxidative stress-related genes. Specifically, abnormal ultrastructural and ΔΨm changes occurred earlier than cell death in the ketamine-induced toxicity process. Furthermore, Trolox significantly decreased ROS generation and attenuated cell death caused by ketamine in a dose-dependent manner. In conclusion, this study illustrates that ketamine time- and dose-dependently induces human neurotoxicity via ROS-mediated mitochondrial apoptosis pathway and that these side effects can be prevented by the antioxidant agent Trolox. Thus, hESC-derived neurons might provide a promising tool for studying anesthetic-induced developmental neurotoxicity and prevention strategies. PMID:22873495

  16. Involvement of mitochondrial activity in mediating ELF-EMF stimulatory effect on human sperm motility.

    Science.gov (United States)

    Iorio, Roberto; Delle Monache, Simona; Bennato, Francesca; Di Bartolomeo, Claudia; Scrimaglio, Renato; Cinque, Benedetta; Colonna, Rosella Cardigno

    2011-01-01

    It has recently been reported that the exposure of human spermatozoa to an extremely low frequency (ELF) electromagnetic field (EMF) with a square waveform of 5 mT amplitude and frequency of 50 Hz improves sperm motility. The functional relationship between the energy metabolism and the enhancement of human sperm motility induced by ELF-EMF was investigated. Sperm exposure to ELF-EMF resulted in a progressive and significant increase of mitochondrial membrane potential and levels of ATP, ADP and NAD(+) that was associated with a progressive and significant increase in the sperm kinematic parameters. No significant effects were detected on other parameters such as ATP/ADP ratio and energy charge. When carbamoyl cyanide m-chlorophenylhydrazone (CICCP) was applied to inhibit the oxidative phosphorylation in the mitochondria, the values of energy parameters and motility in the sperm incubated in the presence of glucose and exposed to ELF-EMF did not change, thus indicating that the glycolysis was not involved in mediating ELF-EMF stimulatory effect on motility. By contrast, when pyruvate and lactate were provided instead of glucose, the energy status and motility increased significantly in ELF-EMF-treated sperm. Under these culture conditions, the inhibition of glycolitic metabolism by 2-deoxy-D-glucose (DOG) again resulted in increased values of energy and kinematic parameters, indicating that gluconeogenesis was not involved in producing glucose for use in glycolysis. We concluded that the key role in mediating the stimulatory effects exerted by ELF-EMF on human sperm motility is played by mitochondrial oxidative phosphorylation rather than glycolysis. © 2010 Wiley-Liss, Inc.

  17. Mitochondrial approaches to protect against cardiac ischemia and reperfusion injury

    Directory of Open Access Journals (Sweden)

    Amadou K.S. Camara

    2011-04-01

    Full Text Available The mitochondrion is a vital component in cellular energy metabolism and intracellular signaling processes. Mitochondria are involved in a myriad of complex signaling cascades regulating cell death vs. survival. Importantly, mitochondrial dysfunction and the resulting oxidative and nitrosative stress are central in the pathogenesis of numerous human maladies including cardiovascular diseases, neurodegenerative diseases, diabetes, and retinal diseases, many of which are related. This review will examine the emerging understanding of the role of mitochondria in the etiology and progression of cardiovascular diseases and will explore potential therapeutic benefits of targeting the organelle in attenuating the disease process. Indeed, recent advances in mitochondrial biology have led to selective targeting of drugs designed to modulate or manipulate mitochondrial function, to the use of light therapy directed to the mitochondrial function, and to modification of the mitochondrial genome for potential therapeutic benefit. The approach to rationally treat mitochondrial dysfunction could lead to more effective interventions in cardiovascular diseases that to date have remained elusive. The central premise of this review is that if mitochondrial abnormalities contribute to the etiology of cardiovascular diseases (e.g. ischemic heart disease, alleviating the mitochondrial dysfunction will contribute to mitigating the severity or progression of the disease. To this end, this review will provide an overview of our current understanding of mitochondria function in cardiovascular diseases as well as the potential role for targeting mitochondria with potential drugs or other interventions that lead to protection against cell injury.

  18. Mitochondrial reactive oxygen species mediate the lipopolysaccharide-induced pro-inflammatory response in human gingival fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xue; Wang, Xiaoxuan [Department of Periodontology, Peking University School and Hospital of Stomatology, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, 22 Zhongguancun Avenue South, Haidian District, Beijing 100081 (China); Zheng, Ming, E-mail: zhengm@bjmu.edu.cn [Department of Physiology and Pathophysiology, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing 100191 (China); Luan, Qing Xian, E-mail: kqluanqx@126.com [Department of Periodontology, Peking University School and Hospital of Stomatolo