DOCSLIB.ORG

Complex I Deficiency Due to Loss of Ndufs4 in the Brain Results

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Complex I Deficiency Due to Loss of Ndufs4 in the Brain Results Complex I deficiency due to loss of Ndufs4 in the brain results in progressive encephalopathy resembling Leigh syndrome Albert Quintanaa,1, Shane E. Krusea,1, Raj P. Kapurb, Elisenda Sanzc, and Richard D. Palmitera,2 aHoward Hughes Medical Institute and Department of Biochemistry, University of Washington, Seattle, WA 98195; bDepartment of Laboratories, Seattle Children’s Hospital, Seattle, WA 98105; and cDepartment of Pharmacology, University of Washington, Seattle, WA 98195 Contributed by Richard D. Palmiter, May 5, 2010 (sent for review April 22, 2010) To explore the lethal, ataxic phenotype of complex I deficiency in least one intact Ndufs4 allele are indistinguishable from WT Ndufs4 knockout (KO) mice, we inactivated Ndufs4 selectively in mice, and they are sometimes used interchangeably with WT as neurons and glia (NesKO mice). NesKO mice manifested the same controls (CT). To examine the role of the CNS in pathology, we symptoms as KO mice including retarded growth, loss of motor restricted the inactivation of Ndufs4 gene to neurons and lox/lox ability, breathing abnormalities, and death by ∼7 wk. Progressive astroglial cells by crossing the Ndufs4 mice with mice neuronal deterioration and gliosis in specific brain areas corre- expressing Cre recombinase from the Nestin locus (19) to create sponded to behavioral changes as the disease advanced, with mice that we refer to as NesKO mice. We confirmed that Nestin- early involvement of the olfactory bulb, cerebellum, and vestibular Cre results in recombination primarily in the CNS by crossing the nuclei. Neurons, particularly in these brain regions, had aberrant mice with a Rosa26-reporter line and by PCR analysis of DNA mitochondrial morphology. Activation of caspase 8, but not cas- isolated from various organs (Fig. S1A). These data agree with pase 9, in affected brain regions implicate the initiation of the the known robust expression of Nestin in the mouse brain with extrinsic apoptotic pathway. Limited caspase 3 activation and lower levels in a few cell types in heart, kidney, lung, pancreas, the predominance of ultrastructural features of necrotic cell death and testes (19). suggest a switch from apoptosis to necrosis in affected neurons. These data suggest that dysfunctional complex I in specific brain Complex I Activity Is Depressed in Brain of NesKO Mice. Enriched MEDICAL SCIENCES regions results in progressive glial activation that promotes neu- mitochondria were prepared from liver and brain to measure ronal death that ultimately results in mortality. respiratory capacity. Normal rotenone-sensitive complex I ac- tivity was detected in submitochondrial particles (SMPs) isolated cerebellum | mitochondria | gliosis | neurodegeneration | vestibular from liver of NesKO or CT mice; however, complex I activity was nucleus very low or absent in SMPs derived from NesKO brain tissue compared with CT (Fig. S1B). Complex I–dependent O2 con- eural pathologies frequently result from dysfunctional mi- sumption by brain tissue from NesKO mice was depressed ∼50% Ntochondria, and Leigh syndrome (LS) is a common clinical compared with that in CT mice, whereas complex II and IV phenotype (1). LS, or subacute necrotizing encephalopathy, is activities were unaffected (Fig. S1 C and D). The loss of complex a progressive neurodegenerative disorder (2) affecting 1 in I activity was independent of the age of the mouse. These results 40,000 live births (3). LS is regarded as the most common in- with NesKO mice are identical to those observed in the brains of fantile mitochondrial disorder, and most patients exhibit symp- total KO mice (18). toms before 1 mo of age (4, 5). Several cases of adult-onset LS have also been reported recently (6–10). In vivo imaging tech- Nearly Identical Phenotype of KO and NesKO Mice. NesKO mice had niques such as MRI reveal bilateral hyperintense lesions in the a phenotype similar to that of total KO mice (18). By postnatal basal ganglia, thalamus, substantia nigra, brainstem, cerebellar day 21 (P21), most NesKO mice were smaller than control lit- white matter and cortex, cerebral white matter, or spinal cord of termates and reached a maximum body weight of ∼12 g at ∼P30 LS patients (6, 11–14). The lesions usually correlate with gliosis, (Fig. S1E). Resting body temperature of NesKO mice was ∼2 oC demyelination, capillary proliferation, and/or necrosis (10, 15). lower than controls after P30 (Fig. S1F). NesKO mice occa- Behavioral symptoms of LS patients can include (with a wide sionally experienced cataracts, ptosis, or optic atrophy. Even variety of clinical presentation) developmental retardation, hy- when their eyes appeared normal, the mice often had defective potonia, ataxia, spasticity, dystonia, weakness, optic atrophy, visual acuity as measured by Morris water maze, visual cliff test, defects in eye or eyelid movement, hearing impairment, and visual placing (Fig. S1G). However, even KO mice with breathing abnormalities, dysarthria, swallowing difficulties, fail- defective vision were able to distinguish light from dark (Fig. ure to thrive, and gastrointestinal problems (4–6, 16, 17). The S1H). Starting at ∼P35, NesKO mice developed severe ataxia: cause of death in most LS cases is unclear, and the lack of they had splayed legs, became unresponsive to a firm nudge, a genetic model to study the disease progression and cause of were slow and awkward at righting themselves, and sometimes death has impeded the development of adequate treatment. became so unstable they would lose their balance and fall over. Prognosis for LS (and most diseases resulting from mitochon- drial dysfunction) is very poor; there is no cure and treatment is often ineffective (5). Thus, a murine model of this disease should Author contributions: A.Q., S.E.K., and R.D.P. designed research; A.Q., S.E.K., R.P.K., and allow a better means of studying the mechanism(s) underlying E.S. performed research; A.Q., S.E.K., R.P.K., and E.S. analyzed data; and A.Q., S.E.K., and the encephalopathy and should allow a more facile investigation R.D.P. wrote the paper. of potential therapies. The authors declare no conflict of interest. Freely available online through the PNAS open access option. Results 1A.Q. and S.E.K. contributed equally to this work. Mice Lacking Ndufs4 in Nervous System Resemble Total Knockout. 2To whom correspondence should be addressed. E-mail: [email protected]. Mice lacking Ndufs4 (Ndufs4 KO) in all cells develop a complex This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10. phenotype and die by postnatal day 50 (P50) (18). Mice with at 1073/pnas.1006214107/-/DCSupplemental. www.pnas.org/cgi/doi/10.1073/pnas.1006214107 PNAS Early Edition | 1of6 Downloaded by guest on September 27, 2021 NesKO mice >P40 were unable to maintain balance on a 7-mm- wide ledge, failed a negative geotaxis test, attempted to clasp a hind leg when suspended by their tail, and fell from a rotating rod very quickly, in contrast to CT mice (Fig. S1I). NesKO mice were very submissive and rarely vocalized even when stressed by handling, tail clipping for genotyping, or in response to a toe pinch (percent vocalization during toe pinch assay: WT, 91.7%, n = 12, P < 0.0001; NesKO and KO, 18.0%, n = 50, P < 0.0001). Some NesKO mice had spontaneous tonic–clonic seizures (∼1/20 NesKO and KO mice), whereas others developed seizures in response to handling (∼1/10 NesKO and KO mice), and the frequency of seizures increased with disease progression. In- termittent breathing irregularities were detected as early as P14 and included hypo- or hyperventilation, but most often involved Fig. 1. Vacuolation and vascular proliferation in NesKO and KO mice. (A) gasping activity. Between P35 and P50, the NesKO mice began to No pathology is observed in H&E staining of brain sections of CT animals (n = lose weight, their ataxia worsened, and they died shortly there- 5). (B and C) In contrast, both late-stage NesKO (B, n = 5) and KO (C, n =5) after. The only significant difference between the phenotype of mice show marked vacuolation in the VN (black arrows; Inset shows higher NesKO mice and complete KO mice is that the latter manifest magnification of indicated area) and, to a lesser extent, in deep cerebellar – a lag time between the exogenic phase of club hair growth and nuclei (white arrow). (D F) Vascular proliferation, as assessed by laminin the anagenic phase of the next hair cycle, resulting in ∼7-d pe- staining, was increased around the VN in NesKO (E) and KO (F) mice com- pared with CT (D). (Scale bar, A–F, 125 μm; Inset, 25 μm.) riod without hair or pigment (18), whereas NesKO mice had a normal hair cycle. An extensive summary of the phenotypes of KO and NesKO mice is provided in Table S1. with the behavioral score described (Table S2). Frozen brain sections from NesKO (n = 5) and KO mice (n = 5) at different Progression of Behavioral Phenotype. Having established that the stages, as well as CT mice (n = 5), were analyzed. A similar pattern major features of the Ndufs4 KO pathology are of neurological of activation in astrocytes and microglial cells appeared simulta- origin, we set out to define the brain regions affected by the loss of neously in the brains of NesKO and KO mice, with overt lesions in Ndufs4 and to correlate pathological changes in the brain with the areas where vacuolation was detected in H&E-stained sec- progression of the behavioral phenotype. A scoring system was tions. NesKO mice had a higher frequency of hemorrhages in established based on weight gain, body temperature, various midbrain, and of gliosis and spongiform lesions in the anterior measures of locomotor skill and activity, touch response, and cerebellum than KO mice. CT animals did not show astroglial trunk curl, rather than age alone, to account for the asynchronous activation and microglial cells retained a ramified morphology progression of the phenotype in different mice.
Load more

Recommended publications
  • Two Transgenic Mouse Models for Β-Subunit Components of Succinate-Coa Ligase Yielding Pleiotropic Metabolic Alterations
    Two transgenic mouse models for -subunit components of succinate-CoA ligase yielding pleiotropic metabolic alterations Kacso, Gergely; Ravasz, Dora; Doczi, Judit; Németh, Beáta; Madgar, Ory; Saada, Ann; Ilin, Polina; Miller, Chaya; Ostergaard, Elsebet; Iordanov, Iordan; Adams, Daniel; Vargedo, Zsuzsanna; Araki, Masatake; Araki, Kimi; Nakahara, Mai; Ito, Haruka; Gál, Aniko; Molnár, Mária J; Nagy, Zsolt; Patocs, Attila; Adam-Vizi, Vera; Chinopoulos, Christos Published in: Biochemical Journal DOI: 10.1042/BCJ20160594 Publication date: 2016 Document version Publisher's PDF, also known as Version of record Document license: CC BY Citation for published version (APA): Kacso, G., Ravasz, D., Doczi, J., Németh, B., Madgar, O., Saada, A., Ilin, P., Miller, C., Ostergaard, E., Iordanov, I., Adams, D., Vargedo, Z., Araki, M., Araki, K., Nakahara, M., Ito, H., Gál, A., Molnár, M. J., Nagy, Z., ... Chinopoulos, C. (2016). Two transgenic mouse models for -subunit components of succinate-CoA ligase yielding pleiotropic metabolic alterations. Biochemical Journal, 473(20), 3463-3485. https://doi.org/10.1042/BCJ20160594 Download date: 02. okt.. 2021 Biochemical Journal (2016) 473 3463–3485 DOI: 10.1042/BCJ20160594 Research Article Two transgenic mouse models for β-subunit components of succinate-CoA ligase yielding pleiotropic metabolic alterations Gergely Kacso1,2, Dora Ravasz1,2, Judit Doczi1,2, Beáta Németh1,2, Ory Madgar1,2, Ann Saada3, Polina Ilin3, Chaya Miller3, Elsebet Ostergaard4, Iordan Iordanov1,5, Daniel Adams1,2, Zsuzsanna Vargedo1,2, Masatake
    [Show full text]
  • A High-Throughput Approach to Uncover Novel Roles of APOBEC2, a Functional Orphan of the AID/APOBEC Family
    Rockefeller University Digital Commons @ RU Student Theses and Dissertations 2018 A High-Throughput Approach to Uncover Novel Roles of APOBEC2, a Functional Orphan of the AID/APOBEC Family Linda Molla Follow this and additional works at: https://digitalcommons.rockefeller.edu/ student_theses_and_dissertations Part of the Life Sciences Commons A HIGH-THROUGHPUT APPROACH TO UNCOVER NOVEL ROLES OF APOBEC2, A FUNCTIONAL ORPHAN OF THE AID/APOBEC FAMILY A Thesis Presented to the Faculty of The Rockefeller University in Partial Fulfillment of the Requirements for the degree of Doctor of Philosophy by Linda Molla June 2018 © Copyright by Linda Molla 2018 A HIGH-THROUGHPUT APPROACH TO UNCOVER NOVEL ROLES OF APOBEC2, A FUNCTIONAL ORPHAN OF THE AID/APOBEC FAMILY Linda Molla, Ph.D. The Rockefeller University 2018 APOBEC2 is a member of the AID/APOBEC cytidine deaminase family of proteins. Unlike most of AID/APOBEC, however, APOBEC2’s function remains elusive. Previous research has implicated APOBEC2 in diverse organisms and cellular processes such as muscle biology (in Mus musculus), regeneration (in Danio rerio), and development (in Xenopus laevis). APOBEC2 has also been implicated in cancer. However the enzymatic activity, substrate or physiological target(s) of APOBEC2 are unknown. For this thesis, I have combined Next Generation Sequencing (NGS) techniques with state-of-the-art molecular biology to determine the physiological targets of APOBEC2. Using a cell culture muscle differentiation system, and RNA sequencing (RNA-Seq) by polyA capture, I demonstrated that unlike the AID/APOBEC family member APOBEC1, APOBEC2 is not an RNA editor. Using the same system combined with enhanced Reduced Representation Bisulfite Sequencing (eRRBS) analyses I showed that, unlike the AID/APOBEC family member AID, APOBEC2 does not act as a 5-methyl-C deaminase.
    [Show full text]
  • SUCLA2 Mutations Cause Global Protein Succinylation Contributing To
    ARTICLE https://doi.org/10.1038/s41467-020-19743-4 OPEN SUCLA2 mutations cause global protein succinylation contributing to the pathomechanism of a hereditary mitochondrial disease ✉ Philipp Gut 1,2,17 , Sanna Matilainen3,17, Jesse G. Meyer4,14,17, Pieti Pällijeff3, Joy Richard2, Christopher J. Carroll5, Liliya Euro 3, Christopher B. Jackson 3, Pirjo Isohanni3,6, Berge A. Minassian7,8, Reem A. Alkhater9, Elsebet Østergaard10, Gabriele Civiletto2, Alice Parisi2, Jonathan Thevenet2, Matthew J. Rardin4,15, Wenjuan He1, Yuya Nishida1, John C. Newman 1, Xiaojing Liu11,16, Stefan Christen2, ✉ ✉ Sofia Moco 2, Jason W. Locasale 11, Birgit Schilling 4,18 , Anu Suomalainen 3,12,13,18 & 1234567890():,; ✉ Eric Verdin 1,4,18 Mitochondrial acyl-coenzyme A species are emerging as important sources of protein modification and damage. Succinyl-CoA ligase (SCL) deficiency causes a mitochondrial encephalomyopathy of unknown pathomechanism. Here, we show that succinyl-CoA accumulates in cells derived from patients with recessive mutations in the tricarboxylic acid cycle (TCA) gene succinyl-CoA ligase subunit-β (SUCLA2), causing global protein hyper- succinylation. Using mass spectrometry, we quantify nearly 1,000 protein succinylation sites on 366 proteins from patient-derived fibroblasts and myotubes. Interestingly, hyper- succinylated proteins are distributed across cellular compartments, and many are known targets of the (NAD+)-dependent desuccinylase SIRT5. To test the contribution of hyper- succinylation to disease progression, we develop a zebrafish model of the SCL deficiency and find that SIRT5 gain-of-function reduces global protein succinylation and improves survival. Thus, increased succinyl-CoA levels contribute to the pathology of SCL deficiency through post-translational modifications.
    [Show full text]
  • Exclusive Neuronal Expression of SUCLA2 in the Human Brain
    Exclusive neuronal expression of SUCLA2 in the human brain Arpád Dobolyi1, Elsebet Ostergaard2, Attila G. Bagó1,3, Tamás Dóczi4, Miklós Palkovits1,5, Aniko Gál6, Mária J Molnár6, Vera Adam-Vizi7 and Christos Chinopoulos7 1Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, 1094, Hungary; 2Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, 2100, Denmark; 3National Institute of Neurosurgery, Budapest, 1145, Hungary; 4MTA-PTE Clinical MR Research Group, Department of Neurosurgery, University of Pécs, 7623, Pécs, Hungary; 5Human Brain Tissue Bank, Semmelweis University, Budapest, 1094, Hungary; 6Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, 1083, Hungary; 7Department of Medical Biochemistry, Semmelweis University, Hungarian Academy of Sciences-SE Laboratory for Neurobiochemistry, Budapest, 1094, Hungary Address correspondence to: Dr. Christos Chinopoulos, Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary. Tel: +361 4591500 ext. 60024, Fax: +361 2670031. E-mail: [email protected] ABSTRACT SUCLA2 encodes the ATP-forming subunit (A-SUCL- ) of succinyl-CoA ligase, an enzyme of the citric acid cycle. Mutations in SUCLA2 lead to a mitochondrial disorder manifesting as encephalomyopathy with dystonia, deafness and lesions in the basal ganglia. Despite the distinct brain pathology associated with SUCLA2 mutations, the precise localization of SUCLA2 protein has never been investigated. Here we show that immunoreactivity of A-SUCL- in surgical human cortical tissue samples was present exclusively in neurons, identified by their morphology and visualized by double labeling with a fluorescent Nissl dye. A-SUCL- immunoreactivity co-localized >99% with that of the d subunit of the mitochondrial F0-F1 ATP synthase. Specificity of the anti-A-SUCL- antiserum was verified by the absence of labeling in fibroblasts from a patient with a complete deletion of SUCLA2.
    [Show full text]
  • Screen for Abnormal Mitochondrial Phenotypes in Mouse Embryonic Stem Cells Identifies a Model for Succinyl-Coa Ligase Deficiency and Mtdna Depletion Taraka R
    © 2014. Published by The Company of Biologists Ltd | Disease Models & Mechanisms (2014) 7, 271-280 doi:10.1242/dmm.013466 RESOURCE ARTICLE Screen for abnormal mitochondrial phenotypes in mouse embryonic stem cells identifies a model for succinyl-CoA ligase deficiency and mtDNA depletion Taraka R. Donti1,‡, Carmen Stromberger1,*,‡, Ming Ge1, Karen W. Eldin2, William J. Craigen1,3 and Brett H. Graham1,§ ABSTRACT prevalence of mitochondrial disorders might be as high as 1 in 5000, Mutations in subunits of succinyl-CoA synthetase/ligase (SCS), a making mitochondrial disease one of the more common genetic component of the citric acid cycle, are associated with mitochondrial causes of encephalomyopathies and multisystem disease (Schaefer et encephalomyopathy, elevation of methylmalonic acid (MMA), and al., 2004; Elliott et al., 2008; Schaefer et al., 2008). Despite important mitochondrial DNA (mtDNA) depletion. A FACS-based retroviral- insights into clinical, biochemical and molecular features of these mediated gene trap mutagenesis screen in mouse embryonic stem disorders, the underlying molecular pathogenesis remains poorly (ES) cells for abnormal mitochondrial phenotypes identified a gene understood and no clearly effective therapies exist. Mitochondria trap allele of Sucla2 (Sucla2SAβgeo), which was used to generate contain their own genome that consists of a multicopy, ~16.4-kilobase transgenic mice. Sucla2 encodes the ADP-specific β-subunit isoform circular chromosome. This mitochondrial DNA (mtDNA) encodes 13 of SCS. Sucla2SAβgeo homozygotes exhibited recessive lethality, with polypeptides that are subunits of various respiratory chain complexes most mutants dying late in gestation (e18.5). Mutant placenta and as well as 22 tRNAs and two rRNAs required for mitochondrial embryonic (e17.5) brain, heart and muscle showed varying degrees protein translation.
    [Show full text]
  • Succinyl-Coa Synthetase Deficiency in Siblings with Impaired Pyruvate Dehydrogenase Complex (PDC) and Other Oxidative
    Harvard Medical School Succinyl-CoA synthetase deficiency in siblings with impaired pyruvate dehydrogenase complex (PDC) and other oxidative Boston Children’s Hospital enzymes in skeletal muscle without mtDNA depletion Cleveland Medical Center Xiaoping Huanga,, Jirair K. Bedoyanb,c,d,j, Didem Demirbasa, David J. Harrisa,e, Alexander Mironc, Simone Edelheitc, George Grahamed, Suzanne D. DeBrossebc,j, Lee-Jun Wongf, Charles L. Hoppeld,g,h, Douglas S. Kerrd,j, Irina Anselmi, and Gerard T. Berrya,e a Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children’s Hospital (BCH), Boston, MA, USA; b Center for Human Genetics, University Hospitals Cleveland Medical Center (UHCMC), Cleveland, OH, USA; c Department of Genetics and Genome Sciences, Case Western Reserve University (CWRU), Cleveland, OH, USA; d Center for Inherited Disorders of Energy Metabolism (CIDEM), UHCMC, Cleveland, OH, USA; e Department of Pediatrics, Harvard Medical School, Boston, MA, USA; f Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; g Department of Pharmacology, CWRU, Cleveland, OH, USA; h Department of Medicine, CWRU, Cleveland, OH, USA; I Department of Neurology, BCH, Boston, MA USA; and j Department of Pediatrics, CWRU, Cleveland, OH, USA. SUMMARY These authors contributed equally to this work. Mutations in SUCLA2 result in succinyl-CoA ligase (ATP-forming) or succinyl-CoA synthetase (ADP-forming) (A-SCS) deficiency, a mitochondrial tricarboxylic acid cycle disorder (Fig. 1). The phenotype associated with this gene defect is largely encephalomyopathy. We describe two siblings compound heterozygous for SUCLA2 mutations, c.985A>G (p.M329V) and c.920C>T (p.A307V), with parents confirmed as carriers of each mutation.
    [Show full text]
  • Datasheet Blank Template
    SAN TA C RUZ BI OTEC HNOL OG Y, INC . SUCLA2 (H-296): sc-68912 BACKGROUND PRODUCT SUCLA2 (succinate-CoA ligase, ADP-forming, β subunit), also known as A- β, Each vial contains 200 µg IgG in 1.0 ml of PBS with < 0.1% sodium azide SCS- βA or renal carcinoma antigen NY-REN-39, is a 463 amino acid mito - and 0.1% gelatin. chondrial matrix enzyme that belongs to the succinate/malate CoA ligase β subunit family. Widely expressed, SUCLA2 dimerizes with the SCS α sub - APPLICATIONS unit to form SCS-A, an essential component of the tricarboxylic acid cycle. SUCLA2 (H-296) is recommended for detection of SUCLA2 of mouse, rat and Defects in SUCLA2 may be involved in a group of autosomal recessive disor - human origin by Western Blotting (starting dilution 1:200, dilution range ders known as mitochondrial DNA depletion syndromes (MDSs) that are 1:100-1:1000), immunoprecipitation [1-2 µg per 100-500 µg of total protein characterized by a decrease in mitochondrial DNA copy numbers in affected (1 ml of cell lysate)], immunofluorescence (starting dilution 1:50, dilution tissues. Progressive external ophthalmoplegia (PEO), ataxia-neuropathy and range 1:50-1:500) and solid phase ELISA (starting dilution 1:30, dilution range mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) may also be 1:30-1:3000). associated with mutations in SUCLA2. Two isoforms of SUCLA2 exists due to alternative splicing events. SUCLA2 (H-296) is also recommended for detection of SUCLA2 in additional species, including canine, bovine and porcine. REFERENCES Suitable for use as control antibody for SUCLA2 siRNA (h): sc-76598, SUCLA2 1.
    [Show full text]
  • SUCLA2 Gene Succinate-Coa Ligase ADP-Forming Beta Subunit
    SUCLA2 gene succinate-CoA ligase ADP-forming beta subunit Normal Function The SUCLA2 gene provides instructions for making one part (a beta subunit) of an enzyme called succinate-CoA ligase. The body makes two slightly different versions of this enzyme: ADP-forming succinate-CoA ligase (A-SUCL) and GDP-forming succinate- CoA ligase (G-SUCL). Only A-SUCL contains the beta subunit produced from the SUCLA2 gene. This version of the enzyme is most active in tissues that require a large amount of energy, such as those of the brain and muscles. Succinate-CoA ligase plays a critical role in mitochondria, which are structures inside cells that convert the energy from food into a form that cells can use. Within mitochondria, this enzyme is involved in a series of chemical reactions known as the citric acid cycle or Krebs cycle. These reactions allow cells to use oxygen and generate energy. Mitochondria each contain a small amount of DNA, known as mitochondrial DNA or mtDNA. Studies suggest that succinate-CoA ligase interacts with another enzyme, nucleoside diphosphate kinase, to produce and maintain the building blocks of mitochondrial DNA. Having an adequate amount of mitochondrial DNA is essential for normal energy production within cells. Health Conditions Related to Genetic Changes Succinate-CoA ligase deficiency At least four mutations in the SUCLA2 gene have been identified in people with succinate-CoA ligase deficiency. Each of these mutations alters the structure of A- SUCL, reducing the enzyme's activity. However, SUCLA2 gene mutations do not affect the other version of succinate-CoA ligase, G-SUCL.
    [Show full text]
  • REPORT Deficiency of the a Subunit of Succinate–Coenzyme a Ligase
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector REPORT Deficiency of the a Subunit of Succinate–Coenzyme A Ligase Causes Fatal Infantile Lactic Acidosis with Mitochondrial DNA Depletion Elsebet Ostergaard, Ernst Christensen, Elisabeth Kristensen, Bodil Mogensen, Morten Duno, Eric A. Shoubridge, and Flemming Wibrand Fatal infantile lactic acidosis is a severe metabolic disorder characterized by the onset of lactic acidosis within the 1st d of life and early death. We found a combined respiratory-chain enzyme deficiency associated with mitochondrial DNA (mtDNA) depletion in a small consanguineous family with this disorder. To identify the disease-causing gene, we per- formed single-nucleotide polymorphism homozygosity mapping and found homozygous regions on four chromosomes. DNA sequencing revealed a homozygous 2-bp deletion in SUCLG1, a gene that encodes the a subunit of the Krebs-cycle enzyme succinate–coenzyme A ligase (SUCL). The mtDNA depletion is likely explained by decreased mitochondrial nucleoside diphosphate kinase (NDPK) activity resulting from the inability of NDPK to form a complex with SUCL. The molecular basis of several disorders resulting from a line, and he had hepatomegaly and severe hypothermia. decrease in mtDNA copy number—the mtDNA-depletion He was hypotonic, and, in the 1st d of life, he became syndromes (MIM 251880)—has been elucidated over the severely acidotic, with a blood pH of 6.7. He had Cheyne- past decade. Mutations in six genes have now been re- Stokes respiration and received respiratory support. Find- ported to cause mtDNA depletion in humans: TP, which ings from an electroencephalogram were severely abnor- is associated with mitochondrial neurogastrointestinal mal, with focal and paroxystic activity, sharp waves, and 1 encephalopathy (MNGIE [MIM 603041]) ; TK2, which triphasic potentials bilaterally.
    [Show full text]
  • Phenotype – Genotype Correlations in Leigh Syndrome: New Insights from a Multicenter Study of 96 Patients
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Helsingin yliopiston digitaalinen arkisto 1 Phenotype – genotype correlations in Leigh syndrome: New insights from a multicenter study of 96 patients Kalliopi Sofou1, Irenaeus de Coo2, Elsebet Østergaard3, Pirjo Isohanni4,5, Karin Naess6, Linda de Meirleir7, Charalampos Tzoulis8,9, Johanna Uusimaa10,11, Tuula Lönnqvist4, Laurence A. Bindoff8,9, Már Tulinius1, Niklas Darin1 1Department of Pediatrics, The Queen Silvia Children’s Hospital, University of Gothenburg, Gothenburg, Sweden 2Department of Neurology, Erasmus MC, Rotterdam, The Netherlands 3Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark 4Department of Paediatric Neurology, Children's Hospital, University of Helsinki, Helsinki University Hospital, Helsinki, Finland 5Research Programs Unit, Molecular Neurology, Biomedicum-Helsinki, University of Helsinki, Helsinki, Finland 6Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden 7Department of Paediatric Neurology, University Hospital Vrije Universiteit Brussel (VUB), Brussels, Belgium 8Department of Neurology, Haukeland University Hospital, Bergen, Norway 9Department of Clinical Medicine, University of Bergen, Norway 10Institute of Clinical Medicine/Department of Paediatrics, University of Oulu, Oulu, Finland 11Medical Research Center, Oulu University Hospital, Oulu, Finland Correspondence to: Dr. Kalliopi Sofou. Department of Pediatrics, The Queen Silvia Children’s Hospital, SE-416 85 Gothenburg, Sweden. Telephone: +46 31 3436416. Fax: +46 31 257960. E- mail: [email protected]. Word count (main text - revised): 3342 Word count (abstract): 192 2 Abstract Background: Leigh syndrome is a phenotypically and genetically heterogeneous mitochondrial disorder. While some genetic defects are associated with well-described phenotypes, phenotype- genotype correlations in Leigh syndrome are not fully explored.
    [Show full text]
  • Localization of SUCLA2 and SUCLG2 Subunits of Succinyl Coa Ligase
    J Bioenerg Biomembr DOI 10.1007/s10863-014-9586-4 Localization of SUCLA2 and SUCLG2 subunits of succinyl CoA ligase within the cerebral cortex suggests the absence of matrix substrate-level phosphorylation in glial cells of the human brain Arpád Dobolyi & Attila G. Bagó & Aniko Gál & Mária J. Molnár & Miklós Palkovits & Vera Adam-Vizi & Christos Chinopoulos Received: 11 July 2014 /Accepted: 21 September 2014 # Springer Science+Business Media New York 2014 Abstract We have recently shown that the ATP-forming work we sought to identify the cell type(s) harboring SUCLA2 subunit of succinyl-CoA ligase, an enzyme of the SUCLG2 in paraformaldehyde-fixed, free-floating surgical citric acid cycle, is exclusively expressed in neurons of the human cortical tissue samples. Specificity of SUCLG2 anti- human cerebral cortex; GFAP- and S100-positive astroglial serum was supported by co-localization with mitotracker or- cells did not exhibit immunohistoreactivity or in situ hybrid- ange staining of paraformaldehyde-fixed human fibroblast ization reactivity for either SUCLA2 or the GTP-forming cultures, delineating the mitochondrial network. In human SUCLG2. However, Western blotting of post mortem samples cortical tissue samples, microglia and oligodendroglia were revealed a minor SUCLG2 immunoreactivity. In the present identified by antibodies directed against Iba1 and myelin basic protein, respectively. Double immunofluorescence for SUCLG2 and Iba1 or myelin basic protein exhibited no co- A. Dobolyi staining; instead, SUCLG2 appeared to outline the cerebral MTA-ELTE NAP Laboratory of Molecular and Systems Neurobiology, Institute of Biology, Budapest, Hungary microvasculature. In accordance to our previous work there was no co-localization of SUCLA2 immunoreactivity with : A.
    [Show full text]
  • Methylmalonic Acidemia Diagnosis by Laboratory Methods
    Reports of Biochemistry & Molecular Biology Vol. 5, No.1, Oct 2016 Review article www.RBMB.net Methylmalonic Acidemia Diagnosis by Laboratory Methods Fatemeh Keyfi1, 2, Saeed Talebi3, Abdol-Reza Varasteh*2, 4, 5 Abstract Methylmalonic acidemia (MMA) is usually caused by a deficiency of the enzyme methylmalonyl-CoA mutase (MCM), a defect in the transport or synthesis of its cofactor, adenosyl-cobalamin (cblA, cblB, cblC, cblF, cblD, and cblX), or deficiency of the enzyme methylmalonyl-CoA epimerase. A comprehensive diagnostic approach involves investigations of metabolites with tandem mass spectrometry, organic acid analysis with gas chromatography, enzymatic studies with fibroblast cell culture, and finally, mutation analysis. With biochemical techniques and enzymatic assay the reliable characterization of patients with isolated MMA for mutation analysis can be achieved. Reliable classification of these patients is essential for ongoing and prospective studies on treatments, outcomes, and prenatal diagnoses. This article reviews the diagnostic techniques used to characterize patients with MMA. Keywords: Diagnostic techniques, Enzyme assay, Methylmalonic acidemia, Mutation analysis, Organic acid analysis, Tandem mass spectrometry Introduction as 'cbl' type. The cblA type is caused by mutations in Methylmalonic acidemia (MMA) is usually caused by the MMAA gene on 4q31. MMAA is involved in the a deficiency of the enzyme methylmalonyl-CoA synthesis of adenosylcobalamin (AdoCbl), a mutase (MCM, EC 5.4.99.2), a defect in the transport coenzyme for MCM. The cblB type is caused by Downloaded from rbmb.net at 0:44 +0330 on Friday October 1st 2021 or synthesis of its cofactor, adenosyl-cobalamin (cblA, mutations in the MMAB gene on 12q24.
    [Show full text]