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Murgia C, Dehlia A, Guthridge MA. New insights into the nutritional genomics of adult-onset riboflavin-responsive diseases. Nutr Metab (Lond) 2023; 20:42. [PMID: 37845732 PMCID: PMC10580530 DOI: 10.1186/s12986-023-00764-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 10/04/2023] [Indexed: 10/18/2023] Open
Abstract
Riboflavin, or vitamin B2, is an essential nutrient that serves as a precursor to flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN). The binding of the FAD and/or FMN cofactors to flavoproteins is critical for regulating their assembly and activity. There are over 90 proteins in the human flavoproteome that regulate a diverse array of biochemical pathways including mitochondrial metabolism, riboflavin transport, ubiquinone and FAD synthesis, antioxidant signalling, one-carbon metabolism, nitric oxide signalling and peroxisome oxidative metabolism. The identification of patients with genetic variants in flavoprotein genes that lead to adult-onset pathologies remains a major diagnostic challenge. However, once identified, many patients with adult-onset inborn errors of metabolism demonstrate remarkable responses to riboflavin therapy. We review the structure:function relationships of mutant flavoproteins and propose new mechanistic insights into adult-onset riboflavin-responsive pathologies and metabolic dysregulations that apply to multiple biochemical pathways. We further address the vexing issue of how the inheritance of genetic variants in flavoprotein genes leads to an adult-onset disease with complex symptomologies and varying severities. We also propose a broad clinical framework that may not only improve the current diagnostic rates, but also facilitate a personalized approach to riboflavin therapy that is low cost, safe and lead to transformative outcomes in many patients.
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Affiliation(s)
- Chiara Murgia
- The School of Agriculture, Food and Ecosystem Sciences (SAFES), Faculty of Science, The University of Melbourne, Parkville, Australia.
| | - Ankush Dehlia
- School of Life and Environmental Sciences, Deakin University, Burwood, Australia
| | - Mark A Guthridge
- School of Life and Environmental Sciences, Deakin University, Burwood, Australia
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Peng MZ, Shao YX, Li XZ, Zhang KD, Cai YN, Lin YT, Jiang MY, Liu ZC, Su XY, Zhang W, Jiang XL, Liu L. Mitochondrial FAD shortage in SLC25A32 deficiency affects folate-mediated one-carbon metabolism. Cell Mol Life Sci 2022; 79:375. [PMID: 35727412 PMCID: PMC11072207 DOI: 10.1007/s00018-022-04404-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/06/2022] [Accepted: 05/27/2022] [Indexed: 11/03/2022]
Abstract
The SLC25A32 dysfunction is associated with neural tube defects (NTDs) and exercise intolerance, but very little is known about disease-specific mechanisms due to a paucity of animal models. Here, we generated homozygous (Slc25a32Y174C/Y174C and Slc25a32K235R/K235R) and compound heterozygous (Slc25a32Y174C/K235R) knock-in mice by mimicking the missense mutations identified from our patient. A homozygous knock-out (Slc25a32-/-) mouse was also generated. The Slc25a32K235R/K235R and Slc25a32Y174C/K235R mice presented with mild motor impairment and recapitulated the biochemical disturbances of the patient. While Slc25a32-/- mice die in utero with NTDs. None of the Slc25a32 mutations hindered the mitochondrial uptake of folate. Instead, the mitochondrial uptake of flavin adenine dinucleotide (FAD) was specifically blocked by Slc25a32Y174C/K235R, Slc25a32K235R/K235R, and Slc25a32-/- mutations. A positive correlation between SLC25A32 dysfunction and flavoenzyme deficiency was observed. Besides the flavoenzymes involved in fatty acid β-oxidation and amino acid metabolism being impaired, Slc25a32-/- embryos also had a subunit of glycine cleavage system-dihydrolipoamide dehydrogenase damaged, resulting in glycine accumulation and glycine derived-formate reduction, which further disturbed folate-mediated one-carbon metabolism, leading to 5-methyltetrahydrofolate shortage and other folate intermediates accumulation. Maternal formate supplementation increased the 5-methyltetrahydrofolate levels and ameliorated the NTDs in Slc25a32-/- embryos. The Slc25a32K235R/K235R and Slc25a32Y174C/K235R mice had no glycine accumulation, but had another formate donor-dimethylglycine accumulated and formate deficiency. Meanwhile, they suffered from the absence of all folate intermediates in mitochondria. Formate supplementation increased the folate amounts, but this effect was not restricted to the Slc25a32 mutant mice only. In summary, we established novel animal models, which enabled us to understand the function of SLC25A32 better and to elucidate the role of SLC25A32 dysfunction in human disease development and progression.
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Affiliation(s)
- Min-Zhi Peng
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, the Affiliated Hospital of Guangzhou Medical University, 9 Jinsui Road, Guangzhou, China
| | - Yong-Xian Shao
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, the Affiliated Hospital of Guangzhou Medical University, 9 Jinsui Road, Guangzhou, China
| | - Xiu-Zhen Li
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, the Affiliated Hospital of Guangzhou Medical University, 9 Jinsui Road, Guangzhou, China
| | - Kang-Di Zhang
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, the Affiliated Hospital of Guangzhou Medical University, 9 Jinsui Road, Guangzhou, China
| | - Yan-Na Cai
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, the Affiliated Hospital of Guangzhou Medical University, 9 Jinsui Road, Guangzhou, China
| | - Yun-Ting Lin
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, the Affiliated Hospital of Guangzhou Medical University, 9 Jinsui Road, Guangzhou, China
| | - Min-Yan Jiang
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, the Affiliated Hospital of Guangzhou Medical University, 9 Jinsui Road, Guangzhou, China
| | - Zong-Cai Liu
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, the Affiliated Hospital of Guangzhou Medical University, 9 Jinsui Road, Guangzhou, China
| | - Xue-Ying Su
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, the Affiliated Hospital of Guangzhou Medical University, 9 Jinsui Road, Guangzhou, China
| | - Wen Zhang
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, the Affiliated Hospital of Guangzhou Medical University, 9 Jinsui Road, Guangzhou, China.
| | - Xiao-Ling Jiang
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, the Affiliated Hospital of Guangzhou Medical University, 9 Jinsui Road, Guangzhou, China.
| | - Li Liu
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, the Affiliated Hospital of Guangzhou Medical University, 9 Jinsui Road, Guangzhou, China.
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Pacheco-Garcia JL, Loginov D, Rizzuti B, Vankova P, Neira JL, Kavan D, Mesa-Torres N, Guzzi R, Man P, Pey AL. A single evolutionarily divergent mutation determines the different FAD-binding affinities of human and rat NQO1 due to site-specific phosphorylation. FEBS Lett 2022; 596:29-41. [PMID: 34817874 DOI: 10.1002/1873-3468.14238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/10/2021] [Accepted: 11/10/2021] [Indexed: 12/13/2022]
Abstract
The phosphomimetic mutation S82D in the cancer-associated, FAD-dependent human NADP(H):quinone oxidoreductase 1 (hNQO1) causes a decrease in flavin-adenine dinucleotide-binding affinity and intracellular stability. We test in this work whether the evolutionarily recent neutral mutation R80H in the vicinity of S82 may alter the strong functional effects of S82 phosphorylation through electrostatic interactions. We show using biophysical and bioinformatic analyses that the reverse mutation H80R prevents the effects of S82D phosphorylation on hNQO1 by modulating the local stability. Consistently, in rat NQO1 (rNQO1) which contains R80, the effects of phosphorylation were milder, resembling the behaviour found in hNQO1 when this residue was humanized in rNQO1 (by the R80H mutation). Thus, apparently neutral and evolutionarily divergent mutations may determine the functional response of mammalian orthologues towards phosphorylation.
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Affiliation(s)
| | - Dmitry Loginov
- Institute of Microbiology of the Czech Academy of Sciences, BioCeV, Praha, Czech Republic
| | - Bruno Rizzuti
- CNR-NANOTEC, SS Rende (CS), Department of Physics, University of Calabria, Rende, Italy
- Instituto de Biocomputación y Física de los Sistemas Complejos (BIFI), Zaragoza, Spain
| | - Pavla Vankova
- Institute of Biotechnology of the Czech Academy of Sciences, BioCeV, Vestec, Czech Republic
- Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jose L Neira
- Instituto de Biocomputación y Física de los Sistemas Complejos (BIFI), Zaragoza, Spain
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche, Spain
| | - Daniel Kavan
- Institute of Microbiology of the Czech Academy of Sciences, BioCeV, Praha, Czech Republic
| | - Noel Mesa-Torres
- Departamento de Química Física, Facultad de Ciencias, Universidad de Granada, Spain
| | - Rita Guzzi
- CNR-NANOTEC, SS Rende (CS), Department of Physics, University of Calabria, Rende, Italy
- Molecular Biophysics Laboratory, Department of Physics, University of Calabria, Rende, Italy
| | - Petr Man
- Institute of Microbiology of the Czech Academy of Sciences, BioCeV, Praha, Czech Republic
| | - Angel L Pey
- Departamento de Química Física, Unidad de Excelencia de Química aplicada a Biomedicina y Medioambiente e Instituto de Biotecnología, Facultad de Ciencias, Universidad de Granada, Spain
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Wen B, Tang S, Lv X, Li D, Xu J, Olsen RKJ, Zhao Y, Li W, Wang T, Shao K, Zhao D, Yan C. Clinical, pathological and genetic features and follow-up of 110 patients with late-onset MADD: A single-center retrospective study. Hum Mol Genet 2021; 31:1115-1129. [PMID: 34718578 DOI: 10.1093/hmg/ddab308] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/28/2021] [Accepted: 10/18/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND To observe a long-term prognosis in late-onset multiple acyl-coenzyme-A dehydrogenation deficiency(MADD) patients and to determine whether riboflavin should be administrated in the long-term and high-dosage manner. METHODS We studied the clinical, pathological and genetic features of 110 patients with late-onset MADD in a single neuromuscular center. The plasma riboflavin levels and a long-term follow-up were performed. RESULTS Fluctuating proximal muscle weakness, exercise intolerance and dramatic responsiveness to riboflavin treatment were essential clinical features for all 110 MADD patients. Among them, we identified 106 cases with ETFDH variants, 1 case with FLAD1 variants and 3 cases without causal variants. On muscle pathology, fibers with cracks, atypical ragged red fibers(aRRFs) and diffuse decrease of SDH activity were the distinctive features of these MADD patients. The plasma riboflavin levels before treatment were significantly decreased in these patients as compared to healthy controls. Among 48 MADD patients with a follow-up of 6.1 years on average, 31 patients were free of muscle weakness recurrence, while 17 patients had episodes of slight muscle weakness upon riboflavin withdrawal, but recovered after retaking a small-dose of riboflavin for a short-term. Multivariate Cox regression analysis showed vegetarian diet and masseter weakness were independent risk factors for muscle weakness recurrence. CONCLUSION Fibers with cracks, aRRFs and diffuse decreased SDH activity distinguish MADD from other genotypes of lipid storage myopathy. For late-onset MADD, increased fatty acid oxidation and reduced riboflavin levels can induce episodes of muscle symptoms, which can be treated by short-term and small-dose of riboflavin therapy.
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Affiliation(s)
- Bing Wen
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, Shandong, China
| | - Shuyao Tang
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, Shandong, China
| | - Xiaoqing Lv
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, Shandong, China
| | - Duoling Li
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, Shandong, China
| | - Jingwen Xu
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, Shandong, China
| | - Rikke Katrine Jentoft Olsen
- Research Unit for Molecular Medicine, Department for Clinical Medicine, Aarhus University and Aarhus University Hospital, 8200 Aarhus N, Denmark
| | - Yuying Zhao
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, Shandong, China
| | - Wei Li
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, Shandong, China
| | - Tan Wang
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, Shandong, China
| | - Kai Shao
- Department of Central Laboratory, Qilu Hospital (Qingdao), Cheeloo College of Medicine, Shandong University, Qingdao 266035, Shandong, China
| | - Dandan Zhao
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, Shandong, China
| | - Chuanzhu Yan
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, Shandong, China.,Brain Science Research Institute, Qilu Hospital, Shandong University, Shandong University, Jinan 250012, Shandong, China
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Mereis M, Wanders RJA, Schoonen M, Dercksen M, Smuts I, van der Westhuizen FH. Disorders of flavin adenine dinucleotide metabolism: MADD and related deficiencies. Int J Biochem Cell Biol 2021; 132:105899. [PMID: 33279678 DOI: 10.1016/j.biocel.2020.105899] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 11/27/2020] [Accepted: 11/30/2020] [Indexed: 12/13/2022]
Abstract
Multiple acyl-coenzyme A dehydrogenase deficiency (MADD), or glutaric aciduria type II (GAII), is a group of clinically heterogeneous disorders caused by mutations in electron transfer flavoprotein (ETF) and ETF-ubiquinone oxidoreductase (ETFQO) - the two enzymes responsible for the re-oxidation of enzyme-bound flavin adenine dinucleotide (FADH2) via electron transfer to the respiratory chain at the level of coenzyme Q10. Over the past decade, an increasing body of evidence has further coupled mutations in FAD metabolism (including intercellular riboflavin transport, FAD biosynthesis and FAD transport) to MADD-like phenotypes. In this review we provide a detailed description of the overarching and specific metabolic pathways involved in MADD. We examine the eight associated genes (ETFA, ETFB, ETFDH, FLAD1, SLC25A32 and SLC52A1-3) and clinical phenotypes, and report ∼436 causative mutations following a systematic literature review. Finally, we focus attention on the value and shortcomings of current diagnostic approaches, as well as current and future therapeutic options for MADD and its phenotypic disorders.
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Affiliation(s)
- Michelle Mereis
- Human Metabolomics, North-West University, Potchefstroom, South Africa
| | - Ronald J A Wanders
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centre, University of Amsterdam, Amsterdam, the Netherlands
| | - Maryke Schoonen
- Human Metabolomics, North-West University, Potchefstroom, South Africa; Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
| | - Marli Dercksen
- Human Metabolomics, North-West University, Potchefstroom, South Africa
| | - Izelle Smuts
- Department of Paediatrics, Steve Biko Academic Hospital, University of Pretoria, South Africa
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Calloni G, Vabulas RM. Mammalian Flavoproteome Analysis Using Label-Free Quantitative Mass Spectrometry. Methods Mol Biol 2021; 2280:263-273. [PMID: 33751441 DOI: 10.1007/978-1-0716-1286-6_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Human flavin cofactor-containing enzymes constitute a small, but highly important flavoproteome. Its stability is required to ensure key metabolic functions, such as oxidative phosphorylation and beta-oxidation of fatty acid. Flavoproteome disfunction due to mutations of individual proteins or because of the lack of FMN and FAD precursor riboflavin (vitamin B2) results in clinically relevant abnormal cellular states and diseases. Current technical possibilities in the field of the quantitative mass spectrometry of proteins allow studying the flavoproteome changes under different stress conditions, including the deficiency of vitamin B2. The biological readouts of flavoenzyme destabilization, such as protein degradation and aggregation, provide important insights into the molecular mechanisms of metabolic adaptation to nutrient deficiency. The proteomic-scale studies of protein stability have significant novelty potential in basic and applied biomedical research.
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Affiliation(s)
| | - R Martin Vabulas
- Charité - Universitätsmedizin Berlin, Institute of Biochemistry, Berlin, Germany.
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Functional Recovery of a GCDH Variant Associated to Severe Deflavinylation—Molecular Insights into Potential Beneficial Effects of Riboflavin Supplementation in Glutaric Aciduria-Type I Patients. Int J Mol Sci 2020; 21:ijms21197063. [PMID: 32992790 PMCID: PMC7583906 DOI: 10.3390/ijms21197063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 11/16/2022] Open
Abstract
Riboflavin is the biological precursor of two important flavin cofactors—flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN)—that are critical prosthetic groups in several redox enzymes. While dietary supplementation with riboflavin is a recognized support therapy in several inborn errors of metabolism, it has yet unproven benefits in several other pathologies affecting flavoproteins. This is the case for glutaric aciduria type I (GA-I), a rare neurometabolic disorder associated with mutations in the GCDH gene, which encodes for glutaryl-coenzyme A (CoA) dehydrogenase (GCDH). Although there are a few reported clinical cases that have responded to riboflavin intake, there is still not enough molecular evidence supporting therapeutic recommendation. Hence, it is necessary to elucidate the molecular basis in favor of riboflavin supplementation in GA-I patients. Here, using a combination of biochemical and biophysical methodologies, we investigate the clinical variant GCDH-p.Val400Met as a model for a phenotype associated with severe deflavinylation. Through a systematic analysis, we establish that recombinant human GCDH-p.Val400Met is expressed in a nonfunctional apo form, which is mainly monomeric rather than tetrameric. However, we show that exogenous FAD is a driver for structural reorganization of the mutant enzyme with concomitant functional recovery, improved thermolability, and resistance to trypsin digestion. Overall, these results establish proof of principle for the beneficial effects of riboflavin supplementation in GA-I patients.
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Mitochondrial and Peroxisomal Alterations Contribute to Energy Dysmetabolism in Riboflavin Transporter Deficiency. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:6821247. [PMID: 32855765 PMCID: PMC7443020 DOI: 10.1155/2020/6821247] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/07/2020] [Accepted: 07/13/2020] [Indexed: 12/16/2022]
Abstract
Riboflavin transporter deficiency (RTD) is a childhood-onset neurodegenerative disorder characterized by progressive pontobulbar palsy, sensory and motor neuron degeneration, sensorineural hearing loss, and optic atrophy. As riboflavin (RF) is the precursor of FAD and FMN, we hypothesize that both mitochondrial and peroxisomal energy metabolism pathways involving flavoproteins could be directly affected in RTD, thus impacting cellular redox status. In the present work, we used induced pluripotent stem cells (iPSCs) from RTD patients to investigate morphofunctional features, focusing on mitochondrial and peroxisomal compartments. Using this model, we document the following RTD-associated alterations: (i) abnormal colony-forming ability and loss of cell-cell contacts, revealed by light, electron, and confocal microscopy, using tight junction marker ZO-1; (ii) mitochondrial ultrastructural abnormalities, involving shape, number, and intracellular distribution of the organelles, as assessed by focused ion beam/scanning electron microscopy (FIB/SEM); (iii) redox imbalance, with high levels of superoxide anion, as assessed by MitoSOX assay accompanied by abnormal mitochondrial polarization state, evaluated by JC-1 staining; (iv) altered immunofluorescence expression of antioxidant systems, namely, glutathione, superoxide dismutase 1 and 2, and catalase, as assessed by quantitatively evaluated confocal microscopy; and (v) peroxisomal downregulation, as demonstrated by levels and distribution of fatty acyl β-oxidation enzymes. RF supplementation results in amelioration of cell phenotype and rescue of redox status, which was associated to improved ultrastructural features of mitochondria, thus strongly supporting patient treatment with RF, to restore mitochondrial- and peroxisomal-related aspects of energy dysmetabolism and oxidative stress in RTD syndrome.
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Riboflavin Deficiency-Implications for General Human Health and Inborn Errors of Metabolism. Int J Mol Sci 2020; 21:ijms21113847. [PMID: 32481712 PMCID: PMC7312377 DOI: 10.3390/ijms21113847] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/20/2020] [Accepted: 05/26/2020] [Indexed: 01/13/2023] Open
Abstract
As an essential vitamin, the role of riboflavin in human diet and health is increasingly being highlighted. Insufficient dietary intake of riboflavin is often reported in nutritional surveys and population studies, even in non-developing countries with abundant sources of riboflavin-rich dietary products. A latent subclinical riboflavin deficiency can result in a significant clinical phenotype when combined with inborn genetic disturbances or environmental and physiological factors like infections, exercise, diet, aging and pregnancy. Riboflavin, and more importantly its derivatives, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), play a crucial role in essential cellular processes including mitochondrial energy metabolism, stress responses, vitamin and cofactor biogenesis, where they function as cofactors to ensure the catalytic activity and folding/stability of flavoenzymes. Numerous inborn errors of flavin metabolism and flavoenzyme function have been described, and supplementation with riboflavin has in many cases been shown to be lifesaving or to mitigate symptoms. This review discusses the environmental, physiological and genetic factors that affect cellular riboflavin status. We describe the crucial role of riboflavin for general human health, and the clear benefits of riboflavin treatment in patients with inborn errors of metabolism.
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10
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Janssen JJE, Grefte S, Keijer J, de Boer VCJ. Mito-Nuclear Communication by Mitochondrial Metabolites and Its Regulation by B-Vitamins. Front Physiol 2019; 10:78. [PMID: 30809153 PMCID: PMC6379835 DOI: 10.3389/fphys.2019.00078] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 01/22/2019] [Indexed: 12/20/2022] Open
Abstract
Mitochondria are cellular organelles that control metabolic homeostasis and ATP generation, but also play an important role in other processes, like cell death decisions and immune signaling. Mitochondria produce a diverse array of metabolites that act in the mitochondria itself, but also function as signaling molecules to other parts of the cell. Communication of mitochondria with the nucleus by metabolites that are produced by the mitochondria provides the cells with a dynamic regulatory system that is able to respond to changing metabolic conditions. Dysregulation of the interplay between mitochondrial metabolites and the nucleus has been shown to play a role in disease etiology, such as cancer and type II diabetes. Multiple recent studies emphasize the crucial role of nutritional cofactors in regulating these metabolic networks. Since B-vitamins directly regulate mitochondrial metabolism, understanding the role of B-vitamins in mito-nuclear communication is relevant for therapeutic applications and optimal dietary lifestyle. In this review, we will highlight emerging concepts in mito-nuclear communication and will describe the role of B-vitamins in mitochondrial metabolite-mediated nuclear signaling.
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Affiliation(s)
| | | | | | - Vincent C. J. de Boer
- Human and Animal Physiology, Wageningen University & Research, Wageningen, Netherlands
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11
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Xu J, Li D, Lv J, Xu X, Wen B, Lin P, Liu F, Ji K, Shan J, Li H, Li W, Zhao Y, Zhao D, Pok JY, Yan C. ETFDH Mutations and Flavin Adenine Dinucleotide Homeostasis Disturbance Are Essential for Developing Riboflavin-Responsive Multiple Acyl-Coenzyme A Dehydrogenation Deficiency. Ann Neurol 2018; 84:659-673. [PMID: 30232818 DOI: 10.1002/ana.25338] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 08/26/2018] [Accepted: 09/09/2018] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Riboflavin-responsive multiple acyl-coenzyme A dehydrogenation deficiency (RR-MADD) is an inherited fatty acid metabolism disorder mainly caused by genetic defects in electron transfer flavoprotein-ubiquinone oxidoreductase (ETF:QO). The variant ETF:QO protein folding deficiency, which can be corrected by therapeutic dosage of riboflavin supplement, has been identified in HEK-293 cells and is believed to be the molecular mechanism of this disease. To verify this hypothesis in vivo, we generated Etfdh (h)A84T knockin (KI) mice. METHODS Tissues from these mice as well as muscle biopsies and fibroblasts from 7 RR-MADD patients were used to examine the flavin adenine dinucleotide (FAD) concentration and ETF:QO protein amount. RESULTS All of the homozygous KI mice (Etfdh (h)A84T/(h)A84T , KI/KI) were initially normal. After being given a high-fat and vitamin B2 -deficient (HF-B2 D) diet for 5 weeks, they developed weight loss, movement ability defects, lipid storage in muscle and liver, and elevated serum acyl-carnitine levels, which are clinically and biochemically similar to RR-MADD patients. Both ETF:QO protein and FAD concentrations were significantly decreased in tissues of HF-B2 D-KI/KI mice and in cultured fibroblasts from RR-MADD patients. After riboflavin treatment, ETF:QO protein increased in proportion to elevated FAD concentrations, but not related to mRNA levels. These results were further confirmed in cultured fibroblasts from RR-MADD patients. INTERPRETATION For the first time, we successfully developed a RR-MADD mice model and confirmed that FAD homeostasis disturbances played a crucial role on the pathomechanism of RR-MADD in this mouse model and culture cells from patients. Supplementation of riboflavin may stabilize variant ETF:QO protein by rebuilding FAD homeostasis. Ann Neurol 2018;84:667-681.
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Affiliation(s)
- Jingwen Xu
- Research Institute of Neuromuscular and Neurodegenerative Disease, Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Duoling Li
- Research Institute of Neuromuscular and Neurodegenerative Disease, Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Jingwei Lv
- Research Institute of Neuromuscular and Neurodegenerative Disease, Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Xuebi Xu
- Research Institute of Neuromuscular and Neurodegenerative Disease, Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Bing Wen
- Research Institute of Neuromuscular and Neurodegenerative Disease, Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Pengfei Lin
- Research Institute of Neuromuscular and Neurodegenerative Disease, Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Fuchen Liu
- Research Institute of Neuromuscular and Neurodegenerative Disease, Department of Neurology, Qilu Hospital, Shandong University, Jinan, China.,Department of Neurobiology, Yale University School of Medicine, New Haven, CT
| | - Kunqian Ji
- Research Institute of Neuromuscular and Neurodegenerative Disease, Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Jingli Shan
- Research Institute of Neuromuscular and Neurodegenerative Disease, Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Honghao Li
- Research Institute of Neuromuscular and Neurodegenerative Disease, Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Wei Li
- Research Institute of Neuromuscular and Neurodegenerative Disease, Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Yuying Zhao
- Research Institute of Neuromuscular and Neurodegenerative Disease, Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Dandan Zhao
- Research Institute of Neuromuscular and Neurodegenerative Disease, Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Joo Y Pok
- Department of Neurology, Yale University, New Haven, CT
| | - Chuanzhu Yan
- Research Institute of Neuromuscular and Neurodegenerative Disease, Department of Neurology, Qilu Hospital, Shandong University, Jinan, China.,Brain Science Research Institute, Shandong University, Jinan, China.,Laboratory of Mitochondrial Medicine, Qilu Hospital (Qingdao), Qingdao, China
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12
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Wesselink E, Koekkoek WAC, Grefte S, Witkamp RF, van Zanten ARH. Feeding mitochondria: Potential role of nutritional components to improve critical illness convalescence. Clin Nutr 2018; 38:982-995. [PMID: 30201141 DOI: 10.1016/j.clnu.2018.08.032] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 08/03/2018] [Accepted: 08/25/2018] [Indexed: 12/30/2022]
Abstract
Persistent physical impairment is frequently encountered after critical illness. Recent data point towards mitochondrial dysfunction as an important determinant of this phenomenon. This narrative review provides a comprehensive overview of the present knowledge of mitochondrial function during and after critical illness and the role and potential therapeutic applications of specific micronutrients to restore mitochondrial function. Increased lactate levels and decreased mitochondrial ATP-production are common findings during critical illness and considered to be associated with decreased activity of muscle mitochondrial complexes in the electron transfer system. Adequate nutrient levels are essential for mitochondrial function as several specific micronutrients play crucial roles in energy metabolism and ATP-production. We have addressed the role of B vitamins, ascorbic acid, α-tocopherol, selenium, zinc, coenzyme Q10, caffeine, melatonin, carnitine, nitrate, lipoic acid and taurine in mitochondrial function. B vitamins and lipoic acid are essential in the tricarboxylic acid cycle, while selenium, α-tocopherol, Coenzyme Q10, caffeine, and melatonin are suggested to boost the electron transfer system function. Carnitine is essential for fatty acid beta-oxidation. Selenium is involved in mitochondrial biogenesis. Notwithstanding the documented importance of several nutritional components for optimal mitochondrial function, at present, there are no studies providing directions for optimal requirements during or after critical illness although deficiencies of these specific micronutrients involved in mitochondrial metabolism are common. Considering the interplay between these specific micronutrients, future research should pay more attention to their combined supply to provide guidance for use in clinical practise. REVISION NUMBER: YCLNU-D-17-01092R2.
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Affiliation(s)
- E Wesselink
- Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
| | - W A C Koekkoek
- Department of Intensive Care Medicine, Gelderse Vallei Hospital, Willy Brandtlaan 10, 6716, Ede, The Netherlands.
| | - S Grefte
- Human and Animal Physiology, Wageningen University, De Elst 1, 6708 DW, Wageningen, The Netherlands.
| | - R F Witkamp
- Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
| | - A R H van Zanten
- Department of Intensive Care Medicine, Gelderse Vallei Hospital, Willy Brandtlaan 10, 6716, Ede, The Netherlands.
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13
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Fan X, Xie B, Zou J, Luo J, Qin Z, D'Gama AM, Shi J, Yi S, Yang Q, Wang J, Luo S, Chen S, Agrawal PB, Li Q, Shen Y. Novel ETFDH mutations in four cases of riboflavin responsive multiple acyl-CoA dehydrogenase deficiency. Mol Genet Metab Rep 2018; 16:15-19. [PMID: 29988809 PMCID: PMC6031868 DOI: 10.1016/j.ymgmr.2018.05.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/30/2018] [Accepted: 05/30/2018] [Indexed: 02/01/2023] Open
Abstract
Multiple acyl-CoA dehydrogenase deficiency (MADD) is an autosomal recessive disorder of fatty acid, amino acid, and choline metabolism caused by mutations in EFTA, EFTB, or ETFDH. Many MADD patients are responsive to treatment with riboflavin, termed riboflavin-responsive MADD (RR-MADD). Here, we report three novel mutations and one previously reported mutation in ETFDH in four RR-MADD patients who presented at various ages, and characterize the corresponding changes in ETF-QO protein structure. Clinicians should consider MADD in the differential diagnosis when patients present with muscle weakness and biochemical abnormalities. Gene testing plays a critical role in confirming the diagnosis of MADD, and may not only prevent patients from invasive testing, but also allow timely initiation of riboflavin treatment. The novel variants in ETFDH and the corresponding clinical features reported here enrich the allelic heterogeneity of RR-MADD and provide insight into genotype-phenotype relationships.
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Affiliation(s)
- Xin Fan
- Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning 530003, People's Republic of China
| | - Bobo Xie
- Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning 530003, People's Republic of China
| | - Jun Zou
- Department of Gastroenterology, The Second Affiliated Hospital, Guangxi Medical University, Nanning 530000, People's Republic of China
| | - Jingsi Luo
- Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning 530003, People's Republic of China
| | - Zailong Qin
- Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning 530003, People's Republic of China
| | - Alissa M D'Gama
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.,The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Jiahai Shi
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong Special Administrative Region
| | - Shang Yi
- Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning 530003, People's Republic of China
| | - Qi Yang
- Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning 530003, People's Republic of China
| | - Jin Wang
- Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning 530003, People's Republic of China
| | - Shiyu Luo
- Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning 530003, People's Republic of China
| | - Shaoke Chen
- Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning 530003, People's Republic of China
| | - Pankaj B Agrawal
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.,The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Qifei Li
- Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning 530003, People's Republic of China.,Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.,The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Yiping Shen
- Genetic and Metabolic Central Laboratory, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning 530003, People's Republic of China.,Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
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14
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Long L, He JZ, Chen Y, Xu XE, Liao LD, Xie YM, Li EM, Xu LY. Riboflavin Depletion Promotes Tumorigenesis in HEK293T and NIH3T3 Cells by Sustaining Cell Proliferation and Regulating Cell Cycle-Related Gene Transcription. J Nutr 2018; 148:834-843. [PMID: 29741716 DOI: 10.1093/jn/nxy047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 02/20/2018] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Riboflavin is an essential component of the human diet and its derivative cofactors play an established role in oxidative metabolism. Riboflavin deficiency has been linked with various human diseases. OBJECTIVE The objective of this study was to identify whether riboflavin depletion promotes tumorigenesis. METHODS HEK293T and NIH3T3 cells were cultured in riboflavin-deficient or riboflavin-sufficient medium and passaged every 48 h. Cells were collected every 5 generations and plate colony formation assays were performed to observe cell proliferation. Subcutaneous tumorigenicity assays in NU/NU mice were used to observe tumorigenicity of riboflavin-depleted HEK293T cells. Mechanistically, gene expression profiling and gene ontology analysis were used to identify abnormally expressed genes induced by riboflavin depletion. Western blot analyses, cell cycle analyses, and chromatin immunoprecipitation were used to validate the expression of cell cycle-related genes. RESULTS Plate colony formation of NIH3T3 and HEK293T cell lines was enhanced >2-fold when cultured in riboflavin-deficient medium for 10-20 generations. Moreover, we observed enhanced subcutaneous tumorigenicity in NU/NU mice following injection of riboflavin-depleted compared with normal HEK293T cells (55.6% compared with 0.0% tumor formation, respectively). Gene expression profiling and gene ontology analysis revealed that riboflavin depletion induced the expression of cell cycle-related genes. Validation experiments also found that riboflavin depletion decreased p21 and p27 protein levels by ∼20%, and increased cell cycle-related and expression-elevated protein in tumor (CREPT) protein expression >2-fold, resulting in cyclin D1 and CDK4 levels being increased ∼1.5-fold, and cell cycle acceleration. We also observed that riboflavin depletion decreased intracellular riboflavin levels by 20% and upregulated expression of riboflavin transporter genes, particularly SLC52A3, and that the changes in CREPT and SLC52A3 correlated with specific epigenetic changes in their promoters in riboflavin-depleted HEK293T cells. CONCLUSION Riboflavin depletion contributes to HEK293T and NIH3T3 cell tumorigenesis and may be a risk factor for tumor development.
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Affiliation(s)
- Lin Long
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area
- Institute of Oncologic Pathology
- Departments of Biochemistry and Molecular Biology
| | - Jian-Zhong He
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area
- Institute of Oncologic Pathology
| | - Ye Chen
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area
- Institute of Oncologic Pathology
| | - Xiu-E Xu
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area
- Institute of Oncologic Pathology
| | - Lian-Di Liao
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area
- Institute of Oncologic Pathology
| | - Yang-Min Xie
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area
- Experimental Animal Center, Shantou University Medical College, Shantou, China
| | - En-Min Li
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area
- Departments of Biochemistry and Molecular Biology
| | - Li-Yan Xu
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area
- Institute of Oncologic Pathology
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15
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Goh LL, Lee Y, Tan ES, Lim JSC, Lim CW, Dalan R. Patient with multiple acyl-CoA dehydrogenase deficiency disease and ETFDH mutations benefits from riboflavin therapy: a case report. BMC Med Genomics 2018; 11:37. [PMID: 29615056 PMCID: PMC5883299 DOI: 10.1186/s12920-018-0356-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 03/26/2018] [Indexed: 12/03/2022] Open
Abstract
Background Lipid storage myopathy (LSM) is a diverse group of lipid metabolic disorders with great variations in the clinical phenotype and age of onset. Classical multiple acyl-CoA dehydrogenase deficiency (MADD) is known to occur secondary to mutations in electron transfer flavoprotein dehydrogenase (ETFDH) gene. Whole exome sequencing (WES) with clinical correlations can be useful in identifying genomic alterations for targeted therapy. Case presentation We report a patient presented with severe muscle weakness and exercise intolerance, suggestive of LSM. Diagnostic testing demonstrated lipid accumulation in muscle fibres and elevated plasma acyl carnitine levels. Exome sequencing of the proband and two of his unaffected siblings revealed compound heterozygous mutations, c.250G > A (p.Ala84Thr) and c.770A > G (p.Tyr257Cys) in the ETFDH gene as the probable causative mutations. In addition, a previously unreported variant c.1042C > T (p.Arg348Trp) in ACOT11 gene was found. This missense variant was predicted to be deleterious but its association with lipid storage in muscle is unclear. The diagnosis of MADD was established and the patient was treated with riboflavin which resulted in rapid clinical and biochemical improvement. Conclusions Our findings support the role of WES as an effective tool in the diagnosis of highly heterogeneous disease and this has important implications in the therapeutic strategy of LSM treatment. Electronic supplementary material The online version of this article (10.1186/s12920-018-0356-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Liuh Ling Goh
- Molecular Diagnostic Laboratory, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore
| | - Yingshan Lee
- Department of Endocrinology, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore
| | - Ee Shien Tan
- Department of Paediatrics, Genetics Services, KK Women's and Children's Hospital, 100 Bukit Timah Road, Singapore, 229899, Singapore
| | - James Soon Chuan Lim
- Biochemical Genetics and National Expanded Newborn Screening, Department of Pathology and Laboratory Medicine, KK Women's and Children's Hospital, 100 Bukit Timah Road, Singapore, 229899, Singapore
| | - Chia Wei Lim
- Molecular Diagnostic Laboratory, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore
| | - Rinkoo Dalan
- Department of Endocrinology, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore. .,Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore. .,Yong Loo Lin School of Medicine, National University of Singapore, 12 Science Drive 2, Singapore, 117549, Singapore.
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16
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Mosegaard S, Bruun GH, Flyvbjerg KF, Bliksrud YT, Gregersen N, Dembic M, Annexstad E, Tangeraas T, Olsen RKJ, Andresen BS. An intronic variation in SLC52A1 causes exon skipping and transient riboflavin-responsive multiple acyl-CoA dehydrogenation deficiency. Mol Genet Metab 2017; 122:182-188. [PMID: 29122468 DOI: 10.1016/j.ymgme.2017.10.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/31/2017] [Accepted: 10/31/2017] [Indexed: 11/23/2022]
Abstract
Vitamin B2, riboflavin is essential for cellular function, as it participates in a diversity of redox reactions central to human metabolism, through its role as precursor for the cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which are electron carriers. The electron transfer flavoprotein (ETF) and its dehydrogenase (ETFDH), uses FAD as cofactor. The ETF and ETFDH are forming the electron transport pathway for many mitochondrial flavoprotein dehydrogenases involved in fatty acid, amino acid and choline metabolism. A variation in either ETF or ETFDH causes multiple acyl-CoA dehydrogenation deficiency (MADD), but genetic variations in the riboflavin metabolism or transportation of riboflavin can also cause MADD. The most common variations are located in the riboflavin transporter 2 (RFVT2) and 3 (RFVT3), that are highly expressed in brain and intestinal tissues, respectively. Deficiency of riboflavin transporter 1 (RFVT1), encoded by the SLC52A1 gene, highly expressed in the placenta, has only been reported once. We here report a case of transient MADD, caused by a heterozygous intronic variation, c.1134+11G>A, in the SLC52A1 gene encoding RFVT1. This variation creates a binding site for the splice inhibitory hnRNP A1 protein and causes exon 4 skipping. Riboflavin deficiency and maternal malnutrition during pregnancy might have been the determining factor in the outcome of this case.
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Affiliation(s)
- Signe Mosegaard
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and University Hospital, 8200 Aarhus N, Denmark
| | - Gitte Hoffmann Bruun
- Department of Biochemistry and Molecular Biology, The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Karen Freund Flyvbjerg
- Department of Biochemistry and Molecular Biology, The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | | | - Niels Gregersen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and University Hospital, 8200 Aarhus N, Denmark
| | - Maja Dembic
- Department of Biochemistry and Molecular Biology, The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Ellen Annexstad
- Ostfold Hospital Trust, Women's and Children's Department, Norway
| | - Trine Tangeraas
- Department of Pediatrics, Oslo University Hospital, Oslo, Norway
| | - Rikke Katrine Jentoft Olsen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and University Hospital, 8200 Aarhus N, Denmark
| | - Brage S Andresen
- Department of Biochemistry and Molecular Biology, The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark.
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17
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Nochi Z, Olsen RKJ, Gregersen N. Short-chain acyl-CoA dehydrogenase deficiency: from gene to cell pathology and possible disease mechanisms. J Inherit Metab Dis 2017; 40:641-655. [PMID: 28516284 DOI: 10.1007/s10545-017-0047-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 03/31/2017] [Accepted: 04/05/2017] [Indexed: 12/15/2022]
Abstract
Short-chain acyl-CoA dehydrogenase deficiency (SCADD) is an inherited disorder of mitochondrial fatty acid oxidation that is characterized by the presence of increased butyrylcarnitine and ethylmalonic acid (EMA) concentrations in plasma and urine. Individuals with symptomatic SCADD may show relatively severe phenotype, while the majority of those who are diagnosed through newborn screening by tandem mass spectrometry may remain asymptomatic. As such, the associated clinical symptoms are very diverse, ranging from severe metabolic or neuromuscular disabilities to asymptomatic. Molecular analysis of affected individuals has identified rare gene variants along with two common gene variants, c.511C > T and c.625G > A. In vitro studies have demonstrated that the common variants as well as the great majority of rare variants, which are missense variants, impair folding, that may lead to toxic accumulation of the encoded protein, and/or metabolites, and initiate excessive production of ROS and chronic oxidative stress. It has been suggested that this cell toxicity in combination with yet unknown factors can trigger disease development. This association and the full implications of SCADD are not commonly appreciated. Accordingly, there is a worldwide discussion of the relationship of clinical manifestation to SCADD, and whether SCAD gene variants are disease associated at all. Therefore, SCADD is not part of the newborn screening programs in most countries, and consequently many patients with SCAD gene variants do not get a diagnosis and the possibilities to be followed up during development.
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Affiliation(s)
- Zahra Nochi
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University Hospital and Faculty of Health, Aarhus University, Palle Juul-Jensens Boulevard 99, Aarhus N, 8200, Denmark.
| | - Rikke Katrine Jentoft Olsen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University Hospital and Faculty of Health, Aarhus University, Palle Juul-Jensens Boulevard 99, Aarhus N, 8200, Denmark
| | - Niels Gregersen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University Hospital and Faculty of Health, Aarhus University, Palle Juul-Jensens Boulevard 99, Aarhus N, 8200, Denmark
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18
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Recognition of enzymes lacking bound cofactor by protein quality control. Proc Natl Acad Sci U S A 2016; 113:12156-12161. [PMID: 27733512 DOI: 10.1073/pnas.1611994113] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Protein biogenesis is tightly linked to protein quality control (PQC). The role of PQC machinery in recognizing faulty polypeptides is becoming increasingly understood. Molecular chaperones and cytosolic and vacuolar degradation systems collaborate to detect, repair, or hydrolyze mutant, damaged, and mislocalized proteins. On the other hand, the contribution of PQC to cofactor binding-related enzyme maturation remains largely unexplored, although the loading of a cofactor represents an all-or-nothing transition in regard to the enzymatic function and thus must be surveyed carefully. Combining proteomics and biochemical analysis, we demonstrate here that cells are able to detect functionally immature wild-type enzymes. We show that PQC-dedicated ubiquitin ligase C-terminal Hsp70-interacting protein (CHIP) recognizes and marks for degradation not only a mutant protein but also its wild-type variant as long as the latter remains cofactor free. A distinct structural feature, the protruding C-terminal tail, which appears in both the mutant and wild-type polypeptides, contributes to recognition by CHIP. Our data suggest that relative insufficiency of apoprotein degradation caused by cofactor shortage can increase amyloidogenesis and aggravate protein aggregation disorders.
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19
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Olsen RKJ, Koňaříková E, Giancaspero TA, Mosegaard S, Boczonadi V, Mataković L, Veauville-Merllié A, Terrile C, Schwarzmayr T, Haack TB, Auranen M, Leone P, Galluccio M, Imbard A, Gutierrez-Rios P, Palmfeldt J, Graf E, Vianey-Saban C, Oppenheim M, Schiff M, Pichard S, Rigal O, Pyle A, Chinnery PF, Konstantopoulou V, Möslinger D, Feichtinger RG, Talim B, Topaloglu H, Coskun T, Gucer S, Botta A, Pegoraro E, Malena A, Vergani L, Mazzà D, Zollino M, Ghezzi D, Acquaviva C, Tyni T, Boneh A, Meitinger T, Strom TM, Gregersen N, Mayr JA, Horvath R, Barile M, Prokisch H. Riboflavin-Responsive and -Non-responsive Mutations in FAD Synthase Cause Multiple Acyl-CoA Dehydrogenase and Combined Respiratory-Chain Deficiency. Am J Hum Genet 2016; 98:1130-1145. [PMID: 27259049 PMCID: PMC4908180 DOI: 10.1016/j.ajhg.2016.04.006] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/13/2016] [Indexed: 12/27/2022] Open
Abstract
Multiple acyl-CoA dehydrogenase deficiencies (MADDs) are a heterogeneous group of metabolic disorders with combined respiratory-chain deficiency and a neuromuscular phenotype. Despite recent advances in understanding the genetic basis of MADD, a number of cases remain unexplained. Here, we report clinically relevant variants in FLAD1, which encodes FAD synthase (FADS), as the cause of MADD and respiratory-chain dysfunction in nine individuals recruited from metabolic centers in six countries. In most individuals, we identified biallelic frameshift variants in the molybdopterin binding (MPTb) domain, located upstream of the FADS domain. Inasmuch as FADS is essential for cellular supply of FAD cofactors, the finding of biallelic frameshift variants was unexpected. Using RNA sequencing analysis combined with protein mass spectrometry, we discovered FLAD1 isoforms, which only encode the FADS domain. The existence of these isoforms might explain why affected individuals with biallelic FLAD1 frameshift variants still harbor substantial FADS activity. Another group of individuals with a milder phenotype responsive to riboflavin were shown to have single amino acid changes in the FADS domain. When produced in E. coli, these mutant FADS proteins resulted in impaired but detectable FADS activity; for one of the variant proteins, the addition of FAD significantly improved protein stability, arguing for a chaperone-like action similar to what has been reported in other riboflavin-responsive inborn errors of metabolism. In conclusion, our studies identify FLAD1 variants as a cause of potentially treatable inborn errors of metabolism manifesting with MADD and shed light on the mechanisms by which FADS ensures cellular FAD homeostasis.
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MESH Headings
- Adult
- Blotting, Western
- Case-Control Studies
- Cells, Cultured
- Electron Transport
- Female
- Fibroblasts/drug effects
- Fibroblasts/metabolism
- Fibroblasts/pathology
- Flavin-Adenine Dinucleotide/metabolism
- Frameshift Mutation/genetics
- Gene Expression Profiling
- Humans
- Infant
- Infant, Newborn
- Liver/drug effects
- Liver/metabolism
- Liver/pathology
- Male
- Mitochondrial Diseases/drug therapy
- Mitochondrial Diseases/genetics
- Mitochondrial Diseases/pathology
- Multiple Acyl Coenzyme A Dehydrogenase Deficiency/drug therapy
- Multiple Acyl Coenzyme A Dehydrogenase Deficiency/genetics
- Multiple Acyl Coenzyme A Dehydrogenase Deficiency/pathology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Mutagenesis, Site-Directed
- Nucleotidyltransferases/genetics
- Protein Binding
- RNA, Messenger/genetics
- Real-Time Polymerase Chain Reaction
- Reverse Transcriptase Polymerase Chain Reaction
- Riboflavin/pharmacology
- Skin/drug effects
- Skin/metabolism
- Skin/pathology
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Vitamin B Complex/pharmacology
- Young Adult
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Affiliation(s)
- Rikke K J Olsen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and University Hospital, 8200 Aarhus N, Denmark.
| | - Eliška Koňaříková
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Teresa A Giancaspero
- Department of Biosciences, Biotechnology, and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Signe Mosegaard
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and University Hospital, 8200 Aarhus N, Denmark
| | - Veronika Boczonadi
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Lavinija Mataković
- Department of Paediatrics, Paracelsus Medical University, SALK Salzburg, 5020 Salzburg, Austria
| | - Alice Veauville-Merllié
- Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Centre de Biologie et Pathologie Est, Centre Hospitalier Universitaire Lyon, 69500 Bron, France
| | - Caterina Terrile
- Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Thomas Schwarzmayr
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Tobias B Haack
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Mari Auranen
- Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, 340 Helsinki, Finland
| | - Piero Leone
- Department of Biosciences, Biotechnology, and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy
| | - Michele Galluccio
- Department DiBEST (Biology, Ecology, and Earth Sciences), University of Calabria, 87036 Arcavacata di Rende, Italy
| | - Apolline Imbard
- Biochemistry Hormonology Laboratory, Robert-Debré Hospital, 75019 Paris, France; Pharmacy Faculty, Paris Sud University, 92019 Chatenay-Malabry, France
| | - Purificacion Gutierrez-Rios
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK; Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Johan Palmfeldt
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and University Hospital, 8200 Aarhus N, Denmark
| | - Elisabeth Graf
- Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Christine Vianey-Saban
- Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Centre de Biologie et Pathologie Est, Centre Hospitalier Universitaire Lyon, 69500 Bron, France
| | - Marcus Oppenheim
- Neurometabolic Unit, National Hospital for Neurology and Neurosurgery, London WCIN 3BG, UK
| | - Manuel Schiff
- INSERM UMR 1141, Hôpital Robert Debré, 75019 Paris, France; Reference Center for Inherited Metabolic Diseases, Robert-Debré Hospital, Assistance Publique - Hôpitaux de Paris, 75019 Paris, France; Faculté de Médecine Denis Diderot, Université Paris Diderot (Paris 7), 75013 Paris, France
| | - Samia Pichard
- Reference Center for Inherited Metabolic Diseases, Robert-Debré Hospital, Assistance Publique - Hôpitaux de Paris, 75019 Paris, France
| | - Odile Rigal
- Biochemistry Hormonology Laboratory, Robert-Debré Hospital, 75019 Paris, France
| | - Angela Pyle
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Patrick F Chinnery
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK; Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0QQ, UK
| | | | - Dorothea Möslinger
- Department of Pediatrics, Medical University of Vienna, 1090 Vienna, Austria
| | - René G Feichtinger
- Department of Paediatrics, Paracelsus Medical University, SALK Salzburg, 5020 Salzburg, Austria
| | - Beril Talim
- Pathology Unit, Department of Pediatrics, Hacettepe University Children's Hospital, 06100 Ankara, Turkey
| | - Haluk Topaloglu
- Neurology Unit, Department of Pediatrics, Hacettepe University Children's Hospital, 06100 Ankara, Turkey
| | - Turgay Coskun
- Metabolism Unit, Department of Pediatrics, Hacettepe University Children's Hospital, 06100 Ankara, Turkey
| | - Safak Gucer
- Pathology Unit, Department of Pediatrics, Hacettepe University Children's Hospital, 06100 Ankara, Turkey
| | - Annalisa Botta
- Medical Genetics Section, Department of Biomedicine and Prevention, Tor Vergata University of Rome, 00133 Rome, Italy
| | - Elena Pegoraro
- Neuromuscular Center, Department of Neurosciences, University of Padova, 35129 Padova, Italy
| | - Adriana Malena
- Neuromuscular Center, Department of Neurosciences, University of Padova, 35129 Padova, Italy
| | - Lodovica Vergani
- Neuromuscular Center, Department of Neurosciences, University of Padova, 35129 Padova, Italy
| | - Daniela Mazzà
- Italy Institute of Medical Genetics, Catholic University of Roma, 00168 Rome, Italy
| | - Marcella Zollino
- Italy Institute of Medical Genetics, Catholic University of Roma, 00168 Rome, Italy
| | - Daniele Ghezzi
- Molecular Neurogenetics Unit, Foundation IRCCS Neurological Institute C. Besta, 20126 Milan, Italy
| | - Cecile Acquaviva
- Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Centre de Biologie et Pathologie Est, Centre Hospitalier Universitaire Lyon, 69500 Bron, France
| | - Tiina Tyni
- Department of Pediatric Neurology, Hospital for Children and Adolescence, Helsinki University Central Hospital, 280 Helsinki, Finland
| | - Avihu Boneh
- Murdoch Childrens Research Institute and University of Melbourne, Melbourne, VIC 3010, Australia
| | - Thomas Meitinger
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Tim M Strom
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Niels Gregersen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and University Hospital, 8200 Aarhus N, Denmark
| | - Johannes A Mayr
- Department of Paediatrics, Paracelsus Medical University, SALK Salzburg, 5020 Salzburg, Austria
| | - Rita Horvath
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Maria Barile
- Department of Biosciences, Biotechnology, and Biopharmaceutics, University of Bari Aldo Moro, 70125 Bari, Italy.
| | - Holger Prokisch
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
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Clinical relevance of short-chain acyl-CoA dehydrogenase (SCAD) deficiency: Exploring the role of new variants including the first SCAD-disease-causing allele carrying a synonymous mutation. BBA CLINICAL 2016; 5:114-9. [PMID: 27051597 PMCID: PMC4816031 DOI: 10.1016/j.bbacli.2016.03.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/07/2016] [Accepted: 03/08/2016] [Indexed: 02/02/2023]
Abstract
Short-chain acyl-coA dehydrogenase deficiency (SCADD) is an autosomal recessive inborn error of mitochondrial fatty acid oxidation caused by ACADS gene alterations. SCADD is a heterogeneous condition, sometimes considered to be solely a biochemical condition given that it has been associated with variable clinical phenotypes ranging from no symptoms or signs to metabolic decompensation occurring early in life. A reason for this variability is due to SCAD alterations, such as the common p.Gly209Ser, that confer a disease susceptibility state but require a complex multifactorial/polygenic condition to manifest clinically. Our study focuses on 12 SCADD patients carrying 11 new ACADS variants, with the purpose of defining genotype–phenotype correlations based on clinical data, metabolite evaluation, molecular analyses, and in silico functional analyses. Interestingly, we identified a synonymous variant, c.765G > T (p.Gly255Gly) that influences ACADS mRNA splicing accuracy. mRNA characterisation demonstrated that this variant leads to an aberrant splicing product, harbouring a premature stop codon. Molecular analysis and in silico tools are able to characterise ACADS variants, identifying the severe mutations and consequently indicating which patients could benefit from a long term follow- up. We also emphasise that synonymous mutations can be relevant features and potentially associated with SCADD. Molecular and functional analysis can identify severe genotypes Patients with severe genotype should receive a long term follow-up. We identified the first SCAD synonymous variant. The first SCAD silent variant was proven to achieve into a disease causing allele.
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Yoshida A, Shiotsu-Ogura Y, Wada-Takahashi S, Takahashi SS, Toyama T, Yoshino F. Blue light irradiation-induced oxidative stress in vivo via ROS generation in rat gingival tissue. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 151:48-53. [DOI: 10.1016/j.jphotobiol.2015.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 06/30/2015] [Accepted: 07/02/2015] [Indexed: 10/23/2022]
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Lund M, Olsen RKJ, Gregersen N. A short introduction to acyl-CoA dehydrogenases; deficiencies and novel treatment strategies. Expert Opin Orphan Drugs 2015. [DOI: 10.1517/21678707.2015.1092869] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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23
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Schiff M, Haberberger B, Xia C, Mohsen AW, Goetzman ES, Wang Y, Uppala R, Zhang Y, Karunanidhi A, Prabhu D, Alharbi H, Prochownik EV, Haack T, Häberle J, Munnich A, Rötig A, Taylor RW, Nicholls RD, Kim JJ, Prokisch H, Vockley J. Complex I assembly function and fatty acid oxidation enzyme activity of ACAD9 both contribute to disease severity in ACAD9 deficiency. Hum Mol Genet 2015; 24:3238-47. [PMID: 25721401 DOI: 10.1093/hmg/ddv074] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 02/23/2015] [Indexed: 01/05/2023] Open
Abstract
Acyl-CoA dehydrogenase 9 (ACAD9) is an assembly factor for mitochondrial respiratory chain Complex I (CI), and ACAD9 mutations are recognized as a frequent cause of CI deficiency. ACAD9 also retains enzyme ACAD activity for long-chain fatty acids in vitro, but the biological relevance of this function remains controversial partly because of the tissue specificity of ACAD9 expression: high in liver and neurons and minimal in skin fibroblasts. In this study, we hypothesized that this enzymatic ACAD activity is required for full fatty acid oxidation capacity in cells expressing high levels of ACAD9 and that loss of this function is important in determining phenotype in ACAD9-deficient patients. First, we confirmed that HEK293 cells express ACAD9 abundantly. Then, we showed that ACAD9 knockout in HEK293 cells affected long-chain fatty acid oxidation along with Cl, both of which were rescued by wild type ACAD9. Further, we evaluated whether the loss of ACAD9 enzymatic fatty acid oxidation affects clinical severity in patients with ACAD9 mutations. The effects on ACAD activity of 16 ACAD9 mutations identified in 24 patients were evaluated using a prokaryotic expression system. We showed that there was a significant inverse correlation between residual enzyme ACAD activity and phenotypic severity of ACAD9-deficient patients. These results provide evidence that in cells where it is strongly expressed, ACAD9 plays a physiological role in fatty acid oxidation, which contributes to the severity of the phenotype in ACAD9-deficient patients. Accordingly, treatment of ACAD9 patients should aim at counteracting both CI and fatty acid oxidation dysfunctions.
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Affiliation(s)
- Manuel Schiff
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA Reference Center for Inborn Errors of Metabolism, Hôpital Robert Debré, APHP, INSERM U1141 and Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Birgit Haberberger
- Institute of Human Genetics, Technische Universität München, Munich, Germany Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Chuanwu Xia
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Al-Walid Mohsen
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA
| | - Eric S Goetzman
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA
| | - Yudong Wang
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA
| | - Radha Uppala
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA
| | - Yuxun Zhang
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA
| | - Anuradha Karunanidhi
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA
| | - Dolly Prabhu
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA
| | - Hana Alharbi
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA
| | - Edward V Prochownik
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA
| | - Tobias Haack
- Institute of Human Genetics, Technische Universität München, Munich, Germany Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Johannes Häberle
- Division of Metabolism, University Children's Hospital Zurich, Zurich, Switzerland
| | - Arnold Munnich
- Institut Imagine and INSERM U781, Sorbonne Paris Cité, Hôpital Necker-Enfants Malades, APHP, Université Paris-Descartes, Paris, France
| | - Agnes Rötig
- Institut Imagine and INSERM U781, Sorbonne Paris Cité, Hôpital Necker-Enfants Malades, APHP, Université Paris-Descartes, Paris, France
| | - Robert W Taylor
- Wellcome Trust Centre for Mitochondrial Research, The Medical School, Newcastle University, Newcastle upon Tyne, UK and
| | - Robert D Nicholls
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Jung-Ja Kim
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Holger Prokisch
- Institute of Human Genetics, Technische Universität München, Munich, Germany Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Jerry Vockley
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA 15224, USA
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Olsen RKJ, Cornelius N, Gregersen N. Genetic and cellular modifiers of oxidative stress: what can we learn from fatty acid oxidation defects? Mol Genet Metab 2013; 110 Suppl:S31-9. [PMID: 24206932 DOI: 10.1016/j.ymgme.2013.10.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 10/08/2013] [Accepted: 10/08/2013] [Indexed: 11/16/2022]
Abstract
During the last two decades the realization has emerged that the phenotype of the majority of inherited genetic diseases, including inborn errors of metabolism, cannot be predicted by the genotype identified in patients. This is true for PKU and in the majority of fatty acid oxidation (FAO) defects, where the genotypes identified in patients may be allocated into two groups. One comprising big deletions and small out-of-frame deletions/insertions as well as severe splice and stop codon changes, generally giving rise to no or very little protein product, and the other group, comprising small in-frame deletions/insertions and missense variations, resulting in misfolding proteins with varying stability. In all cases of FAO defects the pathophysiology may be due to energy insufficiency as well as toxic effects from accumulated enzyme substrates. In patients carrying missense variations, it may in addition be caused by the presence of misfolding proteins. A common effect of accumulated substrates and misfolding proteins is chronic oxidative stress, the severeness of which may depend on a complex interplay of modifying factors, including genetic, cellular, environmental and dietary. In this review we will discuss the hypothesis that especially the amounts of reactive oxygen species (ROS) and reactive nitrogen species (RNS), created in connection with the electron transport chain (ETC), are the driving forces in the balance between cell survival and death. In young and healthy cells small amounts of ROS function as signaling molecules, activating cell protection systems, such as protein quality networks, antioxidant enzymes and metabolic shift from ATP production by the ETC to glycolysis. In the sick and old cell, containing misfolding and damaged proteins, the dynamic range of these protecting systems are narrowed, and cells develop a state of chronic stress, which easier than young and healthy cells may initiate cell death programs like apoptosis and necrosis. We will discuss a wealth of literature that support this hypothesis, which - if supported by studies - is important for new treatment strategies. We conclude that crude antioxidant treatment may not be beneficial, since it may inhibit the survival stress responses. We discuss the ongoing studies to enhance the residual activity of mild misfolding enzyme proteins by cofactor or chemical chaperones or by inducing the transcription of FAO enzyme proteins by bezafibrate with respect to misfolding/distorted conformational proteins ability to create ROS, and the need to know the exact pathophysiological mechanisms in order to suggest new treatment regimes.
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Affiliation(s)
- Rikke Katrine Jentoft Olsen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, Brendstrupgaardsvej 100, Aarhus, Denmark.
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A mutually inhibitory feedback loop between the 20S proteasome and its regulator, NQO1. Mol Cell 2012; 47:76-86. [PMID: 22793692 DOI: 10.1016/j.molcel.2012.05.049] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 02/14/2012] [Accepted: 05/31/2012] [Indexed: 01/18/2023]
Abstract
NAD(P)H:quinone-oxidoreductase-1 (NQO1) is a cytosolic enzyme that catalyzes the reduction of various quinones using flavin adenine dinucleotide (FAD) as a cofactor. NQO1 has been also shown to rescue proteins containing intrinsically unstructured domains, such as p53 and p73, from degradation by the 20S proteasome through an unknown mechanism. Here, we studied the nature of interaction between NQO1 and the 20S proteasome. Our study revealed a double negative feedback loop between NQO1 and the 20S proteasome, whereby NQO1 prevents the proteolytic activity of the 20S proteasome and the 20S proteasome degrades the apo form of NQO1. Furthermore, we demonstrate, both in vivo and in vitro, that NQO1 levels are highly dependent on FAD concentration. These observations suggest a link between 20S proteolysis and the metabolic cellular state. More generally, the results may represent a regulatory mechanism by which associated cofactors dictate the stability of proteins, thus coordinating protein levels with the metabolic status.
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Cornelius N, Frerman FE, Corydon TJ, Palmfeldt J, Bross P, Gregersen N, Olsen RKJ. Molecular mechanisms of riboflavin responsiveness in patients with ETF-QO variations and multiple acyl-CoA dehydrogenation deficiency. Hum Mol Genet 2012; 21:3435-48. [PMID: 22611163 DOI: 10.1093/hmg/dds175] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Riboflavin-responsive forms of multiple acyl-CoA dehydrogenation deficiency (RR-MADD) have been known for years, but with presumed defects in the formation of the flavin adenine dinucleotide (FAD) co-factor rather than genetic defects of electron transfer flavoprotein (ETF) or electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO). It was only recently established that a number of RR-MADD patients carry genetic defects in ETF-QO and that the well-documented clinical efficacy of riboflavin treatment may be based on a chaperone effect that can compensate for inherited folding defects of ETF-QO. In the present study, we investigate the molecular mechanisms and the genotype-phenotype relationships for the riboflavin responsiveness in MADD, using a human HEK-293 cell expression system. We studied the influence of riboflavin and temperature on the steady-state level and the activity of variant ETF-QO proteins identified in patients with RR-MADD, or non- and partially responsive MADD. Our results showed that variant ETF-QO proteins associated with non- and partially responsive MADD caused severe misfolding of ETF-QO variant proteins when cultured in media with supplemented concentrations of riboflavin. In contrast, variant ETF-QO proteins associated with RR-MADD caused milder folding defects when cultured at the same conditions. Decreased thermal stability of the variants showed that FAD does not completely correct the structural defects induced by the variation. This may cause leakage of electrons and increased reactive oxygen species, as reflected by increased amounts of cellular peroxide production in HEK-293 cells expressing the variant ETF-QO proteins. Finally, we found indications of prolonged association of variant ETF-QO protein with the Hsp60 chaperonin in the mitochondrial matrix, supporting indications of folding defects in the variant ETF-QO proteins.
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Affiliation(s)
- Nanna Cornelius
- The Research Unit for Molecular Medicine, Aarhus University Hospital and Department of Clinical Medicine, Aarhus University, Denmark.
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27
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Er TK, Chen CC, Liu YY, Chang HC, Chien YH, Chang JG, Hwang JK, Jong YJ. Computational analysis of a novel mutation in ETFDH gene highlights its long-range effects on the FAD-binding motif. BMC STRUCTURAL BIOLOGY 2011; 11:43. [PMID: 22013910 PMCID: PMC3209457 DOI: 10.1186/1472-6807-11-43] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 10/21/2011] [Indexed: 11/10/2022]
Abstract
Background Multiple acyl-coenzyme A dehydrogenase deficiency (MADD) is an autosomal recessive disease caused by the defects in the mitochondrial electron transfer system and the metabolism of fatty acids. Recently, mutations in electron transfer flavoprotein dehydrogenase (ETFDH) gene, encoding electron transfer flavoprotein:ubiquinone oxidoreductase (ETF:QO) have been reported to be the major causes of riboflavin-responsive MADD. To date, no studies have been performed to explore the functional impact of these mutations or their mechanism of disrupting enzyme activity. Results High resolution melting (HRM) analysis and sequencing of the entire ETFDH gene revealed a novel mutation (p.Phe128Ser) and the hotspot mutation (p.Ala84Thr) from a patient with MADD. According to the predicted 3D structure of ETF:QO, the two mutations are located within the flavin adenine dinucleotide (FAD) binding domain; however, the two residues do not have direct interactions with the FAD ligand. Using molecular dynamics (MD) simulations and normal mode analysis (NMA), we found that the p.Ala84Thr and p.Phe128Ser mutations are most likely to alter the protein structure near the FAD binding site as well as disrupt the stability of the FAD binding required for the activation of ETF:QO. Intriguingly, NMA revealed that several reported disease-causing mutations in the ETF:QO protein show highly correlated motions with the FAD-binding site. Conclusions Based on the present findings, we conclude that the changes made to the amino acids in ETF:QO are likely to influence the FAD-binding stability.
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Affiliation(s)
- Tze-Kiong Er
- Division of Molecular Diagnostics, Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Taiwan
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Lucas TG, Henriques BJ, Rodrigues JV, Bross P, Gregersen N, Gomes CM. Cofactors and metabolites as potential stabilizers of mitochondrial acyl-CoA dehydrogenases. Biochim Biophys Acta Mol Basis Dis 2011; 1812:1658-63. [PMID: 21968293 DOI: 10.1016/j.bbadis.2011.09.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 09/14/2011] [Accepted: 09/15/2011] [Indexed: 12/31/2022]
Abstract
Protein misfolding is a hallmark of a number of metabolic diseases, in which fatty acid oxidation defects are included. The latter result from genetic deficiencies in transport proteins and enzymes of the mitochondrial β-oxidation, and milder disease conditions frequently result from conformational destabilization and decreased enzymatic function of the affected proteins. Small molecules which have the ability to raise the functional levels of the affected protein above a certain disease threshold are thus valuable tools for effective drug design. In this work we have investigated the effect of mitochondrial cofactors and metabolites as potential stabilizers in two β-oxidation acyl-CoA dehydrogenases: short chain acyl-CoA dehydrogenase and the medium chain acyl-CoA dehydrogenase as well as glutaryl-CoA dehydrogenase, which is involved in lysine and tryptophan metabolism. We found that near physiological concentrations (low micromolar) of FAD resulted in a spectacular enhancement of the thermal stabilities of these enzymes and prevented enzymatic activity loss during a 1h incubation at 40°C. A clear effect of the respective substrate, which was additive to that of the FAD effect, was also observed for short- and medium-chain acyl-CoA dehydrogenase but not for glutaryl-CoA dehydrogenase. In conclusion, riboflavin may be beneficial during feverish crises in patients with short- and medium-chain acyl-CoA dehydrogenase as well as in glutaryl-CoA dehydrogenase deficiencies, and treatment with substrate analogs to butyryl- and octanoyl-CoAs could theoretically enhance enzyme activity for some enzyme proteins with inherited folding difficulties.
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Affiliation(s)
- Tânia G Lucas
- Instituto Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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29
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Bioactive food components, cancer cell growth limitation and reversal of glycolytic metabolism. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:697-706. [DOI: 10.1016/j.bbabio.2010.08.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 08/10/2010] [Accepted: 08/15/2010] [Indexed: 02/07/2023]
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Molecular analysis of 51 unrelated pedigrees with late-onset multiple acyl-CoA dehydrogenation deficiency (MADD) in southern China confirmed the most common ETFDH mutation and high carrier frequency of c.250G>A. J Mol Med (Berl) 2011; 89:569-76. [PMID: 21347544 DOI: 10.1007/s00109-011-0725-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 12/12/2010] [Accepted: 12/14/2010] [Indexed: 10/18/2022]
Abstract
Multiple acyl-CoA dehydrogenation deficiency (MADD) is an autosomal recessive disease affecting amino acid, fatty acid, and choline metabolisms and is a common genetic defect responsible for lipid storage myopathy. Most forms of MADD are caused by a deficiency of electron transfer flavoprotein (ETF) or ETF dehydrogenase (ETFDH). However, its molecular feature has not been found uniformly in previous reports of Chinese patients. A large cohort of 56 late-onset MADD patients from 51 unrelated pedigrees in southern China was recruited to investigate a clear correlation between clinical phenotype and molecular genetic basis. All exons of ETFA, ETFB, and ETFDH, including the intron-exon boundaries, and 5' and 3' untranslated regions were directly sequenced. ETFDH deficiencies affected 94.1% (48/51) of the pedigrees. ETFDH-c.250G>A is the most common mutation, representing a high allelic frequency of 83.3% (80/96). Carrier frequency of c.250G>A is estimated to be 1.35% (7/520) in the normal population. A significant reduced expression of ETFDH was identified in the muscle of ETFDH-deficient patients. ETFDH deficiency is a major cause of riboflavin-responsive MADD in southern China, and c.250G>A is an important mutation that could be employed as a fast and reliable screening method.
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Gerards M, van den Bosch BJC, Danhauser K, Serre V, van Weeghel M, Wanders RJA, Nicolaes GAF, Sluiter W, Schoonderwoerd K, Scholte HR, Prokisch H, Rötig A, de Coo IFM, Smeets HJM. Riboflavin-responsive oxidative phosphorylation complex I deficiency caused by defective ACAD9: new function for an old gene. Brain 2010; 134:210-9. [DOI: 10.1093/brain/awq273] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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van Maldegem BT, Duran M, Wanders RJA, Waterham HR, Wijburg FA. Flavin adenine dinucleotide status and the effects of high-dose riboflavin treatment in short-chain acyl-CoA dehydrogenase deficiency. Pediatr Res 2010; 67:304-8. [PMID: 19952864 DOI: 10.1203/pdr.0b013e3181cbd57b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Short-chain acyl-CoA dehydrogenase deficiency (SCADD) is an inborn error, biochemically characterized by increased plasma butyrylcarnitine (C4-C) concentration and increased ethylmalonic acid (EMA) excretion and caused by rare mutations and/or common gene variants in the SCAD encoding gene. Although its clinical relevance is not clear, SCADD is included in most US newborn screening programs. Riboflavin, the precursor of flavin adenine dinucleotide (FAD, cofactor), might be effective for treating SCADD. We assessed the FAD status and evaluated the effects of riboflavin treatment in a prospective open-label cohort study involving 16 patients with SCADD, subdivided into mutation/mutation (mut/mut), mutation/variant (mut/var), and variant/variant (var/var) genotype groups. Blood FAD levels were normal in all patients before therapy, but significantly lower in the mut/var and var/var groups compared with the mut/mut group. Riboflavin treatment resulted in a decrease in EMA excretion in the mut/var group and in a subjective clinical improvement in four patients from this group. However, this improvement persisted after stopping treatment. These results indicate that high-dose riboflavin treatment may improve the biochemical features of SCADD, at least in patients with a mut/var genotype and low FAD levels. As our study could not demonstrate a clinically relevant effect of riboflavin, general use of riboflavin cannot be recommended.
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Palmieri VO, Grattagliano I, Minerva F, Pollice S, Palasciano G, Portincasa P. Liver Function as Assessed by Breath Tests in Patients With Hepatocellular Carcinoma. J Surg Res 2009; 157:199-207. [PMID: 19540521 DOI: 10.1016/j.jss.2008.09.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 08/20/2008] [Accepted: 09/30/2008] [Indexed: 01/26/2023]
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Henriques BJ, Rodrigues JV, Olsen RK, Bross P, Gomes CM. Role of flavinylation in a mild variant of multiple acyl-CoA dehydrogenation deficiency: a molecular rationale for the effects of riboflavin supplementation. J Biol Chem 2008; 284:4222-9. [PMID: 19088074 DOI: 10.1074/jbc.m805719200] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in the genes encoding the alpha-subunit and beta-subunit of the mitochondrial electron transfer flavoprotein (ETF) and the electron transfer flavoprotein:ubiquinone oxidoreductase (ETF:QO) cause multiple acyl-CoA dehydrogenation deficiency (MADD), a disorder of fatty acid and amino acid metabolism. Point mutations in ETF, which may compromise folding, and/or activity, are associated with both mild and severe forms of MADD. Here we report the investigation on the conformational and stability properties of the disease-causing variant ETFbeta-D128N, and our findings on the effect of flavinylation in modulating protein conformational stability and activity. A combination of biochemical and biophysical methods including circular dichroism, visible absorption, flavin, and tryptophan fluorescence emission allowed the analysis of structural changes and of the FAD moiety. The ETFbeta-D128N variant retains the overall fold of the wild type, but under stress conditions its flavin becomes less tightly bound. Flavinylation is shown to improve the conformational stability and biological activity of a destabilized D128N variant protein. Moreover, the presence of flavin prevented proteolytic digestion by avoiding protein destabilization. A patient homozygous for the ETFbeta-D128N mutation developed severe disease symptoms in association with a viral infection and fever. In agreement, our results suggest that heat inactivation of the mutant may be more relevant at temperatures above 37 degrees C. To mimic a situation of fever in vitro, the flavinylation status was tested at 39 degrees C. FAD exerts the effect of a pharmacological chaperone, improving ETF conformation, and yielding a more stable and active enzyme. Our results provide a structural and functional framework that could help to elucidate the role that an increased cellular FAD content obtained from riboflavin supplementation may play in the molecular pathogenesis of not only MADD, but genetic disorders of flavoproteins in general.
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Affiliation(s)
- Bárbara J Henriques
- Instituto Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2780-756 Oeiras, Portugal
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Jethva R, Bennett MJ, Vockley J. Short-chain acyl-coenzyme A dehydrogenase deficiency. Mol Genet Metab 2008; 95:195-200. [PMID: 18977676 PMCID: PMC2720545 DOI: 10.1016/j.ymgme.2008.09.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Revised: 09/23/2008] [Accepted: 09/24/2008] [Indexed: 10/21/2022]
Abstract
Short-chain acyl-CoA dehydrogenase deficiency (SCADD) is a disorder of mitochondrial fatty acid oxidation that leads to the accumulation of butyrylcarnitine and ethylmalonic acid in blood and urine. Originally described with a relatively severe phenotype, most patients are now diagnosed through newborn screening by tandem mass spectrometry and remain asymptomatic. Molecular analysis of affected individuals has identified a preponderance of private inactivating point mutations and one common one present in high frequency in individuals of Ashkenazi Jewish ancestry. In addition, two polymorphic variants have been identified that have little affect on enzyme kinetics but impair folding and stability. Individuals homozygous for one of these variants or compound heterozygous for one of each often show an increased level of ethylmalonic acid excretion that appears not to be clinically significant. The combination of asymptomatic affected newborns and the frequent variants can cause much confusion in evaluating and treating individuals with SCADD. The long-term consequences and the need for chronic therapy remain current topics of contention and investigation.
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Affiliation(s)
- Reena Jethva
- Children’s Hospital of Philadelphia, Division of Human and Molecular Genetics, The Children’s Hospital of Philadelphia, Abramson Research Center, Room 1002, 3615 Civic Center Boulevard, Philadelphia, PA 19104
| | - Michael J. Bennett
- University of Pennsylvania School of Medicine, The Children’s Hospital of Philadelphia, Department of Pathology, 34th Street and Civic Center Blvd., Philadelphia, PA 19104
| | - Jerry Vockley
- University of Pittsburgh, School of Medicine, Department of Pediatrics, Graduate School of Public Health, Department of Human Genetics, Children’s Hospital of Pittsburgh, Division of Medical Genetics, 3705 5th Avenue, Pittsburgh, PA 15213
- To whom correspondence should be addressed
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Gregersen N, Andresen BS, Pedersen CB, Olsen RKJ, Corydon TJ, Bross P. Mitochondrial fatty acid oxidation defects--remaining challenges. J Inherit Metab Dis 2008; 31:643-57. [PMID: 18836889 DOI: 10.1007/s10545-008-0990-y] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 08/13/2008] [Accepted: 08/14/2008] [Indexed: 02/04/2023]
Abstract
Mitochondrial fatty acid oxidation defects have been recognized since the early 1970s. The discovery rate has been rather constant, with 3-4 'new' disorders identified every decade and with the most recent example, ACAD9 deficiency, reported in 2007. In this presentation we will focus on three of the 'old' defects: medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, riboflavin responsive multiple acyl-CoA dehydrogenation (RR-MAD) deficiency, and short-chain acyl-CoA dehydrogenase (SCAD) deficiency. These disorders have been discussed in many publications and at countless conference presentations, and many questions relating to them have been answered. However, continuing clinical and pathophysiological research has raised many further questions, and new ideas and methodologies may be required to answer these. We will discuss these challenges. For MCAD deficiency the key question is why 80% of symptomatic patients are homozygous for the prevalent ACADM gene variation c.985A > G whereas this is found in only approximately 50% of newborns with a positive screen. For RR-MAD deficiency, the challenge is to find the connection between variations in the ETFDH gene and the observed deficiency of a number of different mitochondrial dehydrogenases as well as deficiency of FAD and coenzyme Q(10). With SCAD deficiency, the challenge is to elucidate whether ACADS gene variations are disease-associated, especially when combined with other genetic/cellular/environmental factors, which may act synergistically.
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Affiliation(s)
- Niels Gregersen
- Research Unit for Molecular Medicine, Institute of Clinical Medicine, The Faculty of Health Sciences, Aarhus University, Aarhus N, Denmark.
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Giancaspero TA, Wait R, Boles E, Barile M. Succinate dehydrogenase flavoprotein subunit expression in Saccharomyces cerevisiae--involvement of the mitochondrial FAD transporter, Flx1p. FEBS J 2008; 275:1103-17. [PMID: 18279395 DOI: 10.1111/j.1742-4658.2008.06270.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The mitochondrial FAD transporter, Flx1p, is a member of the mitochondrial carrier family responsible for FAD transport in Saccharomyces cerevisiae. It has also been suggested that it has a role in maintaining the normal activity of mitochondrial FAD-binding enzymes, including lipoamide dehydrogenase and succinate dehydrogenase flavoprotein subunit Sdh1p. A decrease in the amount of Sdh1p in the flx1Delta mutant strain has been determined here to be due to a post-transcriptional control that involves regulatory sequences located upstream of the SDH1 coding sequence. The SDH1 coding sequence and the regulatory sequences located downstream of the SDH1 coding region, as well as protein import and cofactor attachment, seem to be not involved in the decrease in the amount of protein.
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Affiliation(s)
- Teresa A Giancaspero
- Dipartimento di Biochimica e Biologia Molecolare E. Quagliariello, Università degli Studi di Bari, Via Orabona 4, Bari, Italy
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Vockley J, Ensenauer R. Isovaleric acidemia: new aspects of genetic and phenotypic heterogeneity. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2006; 142C:95-103. [PMID: 16602101 PMCID: PMC2652706 DOI: 10.1002/ajmg.c.30089] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Isovaleric acidemia (IVA) is an autosomal recessive inborn error of leucine metabolism caused by a deficiency of the mitochondrial enzyme isovaleryl-CoA dehydrogenase (IVD) resulting in the accumulation of derivatives of isovaleryl-CoA. It was the first organic acidemia recognized in humans and can cause significant morbidity and mortality. Early diagnosis and treatment with a protein restricted diet and supplementation with carnitine and glycine are effective in promoting normal development in severely affected individuals. Both intra- and interfamilial variability have been recognized. Initially, two phenotypes with either an acute neonatal or a chronic intermittent presentation were described. More recently, a third group of individuals with mild biochemical abnormalities who can be asymptomatic have been identified through newborn screening of blood spots by tandem mass spectrometry. IVD is a flavoenzyme that catalyzes the conversion of isovaleryl-CoA to 3-methylcrotonyl-CoA and transfers electrons to the electron transfer flavoprotein. Human IVD has been purified from tissue and recombinant sources and its biochemical and physical properties have been extensively studied. Molecular analysis of the IVD gene from patients with IVA has allowed characterization of different types of mutations in this gene. One missense mutation, 932C>T (A282V), is particularly common in patients identified through newborn screening with mild metabolite elevations and who have remained asymptomatic to date. This mutation leads to a partially active enzyme with altered catalytic properties; however, its effects on clinical outcome and the necessity of therapy are still unknown. A better understanding of the heterogeneity of this disease and the relevance of genotype/phenotype correlations to clinical management of patients are among the challenges remaining in the study of this disorder in the coming years.
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Affiliation(s)
- Jerry Vockley
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh, 3705 Fifth Avenue, Pittsburgh, PA 15238, USA.
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Depeint F, Bruce WR, Shangari N, Mehta R, O'Brien PJ. Mitochondrial function and toxicity: role of the B vitamin family on mitochondrial energy metabolism. Chem Biol Interact 2006; 163:94-112. [PMID: 16765926 DOI: 10.1016/j.cbi.2006.04.014] [Citation(s) in RCA: 268] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Revised: 04/18/2006] [Accepted: 04/18/2006] [Indexed: 01/19/2023]
Abstract
The B vitamins are water-soluble vitamins required as coenzymes for enzymes essential for cell function. This review focuses on their essential role in maintaining mitochondrial function and on how mitochondria are compromised by a deficiency of any B vitamin. Thiamin (B1) is essential for the oxidative decarboxylation of the multienzyme branched-chain ketoacid dehydrogenase complexes of the citric acid cycle. Riboflavin (B2) is required for the flavoenzymes of the respiratory chain, while NADH is synthesized from niacin (B3) and is required to supply protons for oxidative phosphorylation. Pantothenic acid (B5) is required for coenzyme A formation and is also essential for alpha-ketoglutarate and pyruvate dehydrogenase complexes as well as fatty acid oxidation. Biotin (B7) is the coenzyme of decarboxylases required for gluconeogenesis and fatty acid oxidation. Pyridoxal (B6), folate and cobalamin (B12) properties are reviewed elsewhere in this issue. The experimental animal and clinical evidence that vitamin B therapy alleviates B deficiency symptoms and prevents mitochondrial toxicity is also reviewed. The effectiveness of B vitamins as antioxidants preventing oxidative stress toxicity is also reviewed.
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Affiliation(s)
- Flore Depeint
- Department of Pharmaceutical Sciences, University of Toronto, Canada; Department of Nutritional Sciences, University of Toronto, Canada
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Brizio C, Galluccio M, Wait R, Torchetti EM, Bafunno V, Accardi R, Gianazza E, Indiveri C, Barile M. Over-expression in Escherichia coli and characterization of two recombinant isoforms of human FAD synthetase. Biochem Biophys Res Commun 2006; 344:1008-16. [PMID: 16643857 DOI: 10.1016/j.bbrc.2006.04.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Accepted: 04/01/2006] [Indexed: 11/16/2022]
Abstract
FAD synthetase (FADS) (EC 2.7.7.2) is a key enzyme in the metabolic pathway that converts riboflavin into the redox cofactor FAD. Two hypothetical human FADSs, which are the products of FLAD1 gene, were over-expressed in Escherichia coli and identified by ESI-MS/MS. Isoform 1 was over-expressed as a T7-tagged protein which had a molecular mass of 63kDa on SDS-PAGE. Isoform 2 was over-expressed as a 6-His-tagged fusion protein, carrying an extra 84 amino acids at the N-terminal with an apparent molecular mass of 60kDa on SDS-PAGE. It was purified near to homogeneity from the soluble cell fraction by one-step affinity chromatography. Both isoforms possessed FADS activity and had a strict requirement for MgCl(2), as demonstrated using both spectrophotometric and chromatographic methods. The purified recombinant isoform 2 showed a specific activity of 6.8+/-1.3nmol of FAD synthesized/min/mg protein and exhibited a K(M) value for FMN of 1.5+/-0.3microM. This is the first report on characterization of human FADS, and the first cloning and over-expression of FADS from an organism higher than yeast.
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Affiliation(s)
- Carmen Brizio
- Dipartimento di Biochimica e Biologia Molecolare Ernesto Quagliariello, Università degli Studi di Bari, Via Orabona 4, I-70126 Bari, Italy
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41
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Spaan AN, Ijlst L, van Roermund CWT, Wijburg FA, Wanders RJA, Waterham HR. Identification of the human mitochondrial FAD transporter and its potential role in multiple acyl-CoA dehydrogenase deficiency. Mol Genet Metab 2005; 86:441-7. [PMID: 16165386 DOI: 10.1016/j.ymgme.2005.07.014] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Accepted: 07/27/2005] [Indexed: 10/25/2022]
Abstract
Multiple acyl-CoA dehydrogenase deficiency (MADD) or glutaric aciduria type II (GAII) is most often caused by mutations in the genes encoding the alpha- or beta-subunit of electron transfer flavoprotein (ETF) or electron transfer flavoprotein dehydrogenase (ETF-DH). Since not all patients have mutations in these genes, other as yet unidentified genes are predicted to be involved as well. Because all affected mitochondrial flavoproteins in MADD have FAD as a prosthetic group, the underlying defect in these patients may be due to a thus far undisclosed disturbance in the metabolism of FAD. Since a proper mitochondrial flavin balance is maintained by a mitochondrial FAD transporter, a defect of this transporter could also cause an MADD-like phenotype. In yeast, FAD is transported across the mitochondrial inner membrane by the FLX1 protein. An FLX1-mutated Saccharomyces cerevisiae strain exhibits a decreased activity of several mitochondrial flavoproteins. In the present study, we report the identification of the human mitochondrial FAD transporter. Based on sequence similarity to FLX1, we identified two human candidate genes (MFT and N111), which were cloned and characterized by functional expression in an FLX1-mutated yeast strain. Of the two candidate genes, only the previously described mitochondrial folate transporter (MFT) was able to functionally complement the FLX1 mutant. Candidates for mutations in the MFT gene are patients with a clinical suspicion of MADD but without any mutation in the alpha- or beta-subunit of ETF or ETF-DH.
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Affiliation(s)
- András N Spaan
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases (F0-224), Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
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Bafunno V, Giancaspero TA, Brizio C, Bufano D, Passarella S, Boles E, Barile M. Riboflavin uptake and FAD synthesis in Saccharomyces cerevisiae mitochondria: involvement of the Flx1p carrier in FAD export. J Biol Chem 2003; 279:95-102. [PMID: 14555654 DOI: 10.1074/jbc.m308230200] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have studied the functional steps by which Saccharomyces cerevisiae mitochondria can synthesize FAD from cytosolic riboflavin (Rf). Riboflavin uptake into mitochondria took place via a mechanism that is consistent with the existence of (at least two) carrier systems. FAD was synthesized inside mitochondria by a mitochondrial FAD synthetase (EC 2.7.7.2), and it was exported into the cytosol via an export system that was inhibited by lumiflavin, and which was different from the riboflavin uptake system. To understand the role of the putative mitochondrial FAD carrier, Flx1p, in this pathway, an flx1Delta mutant strain was constructed. Coupled mitochondria isolated from flx1Delta mutant cells were compared with wild-type mitochondria with respect to the capability to take up Rf, to synthesize FAD from it, and to export FAD into the extramitochondrial phase. Mitochondria isolated from flx1Delta mutant cells specifically lost the ability to export FAD, but did not lose the ability to take up Rf, FAD, or FMN and to synthesize FAD from Rf. Hence, Flx1p is proposed to be the mitochondrial FAD export carrier. Moreover, deletion of the FLX1 gene resulted in a specific reduction of the activities of mitochondrial lipoamide dehydrogenase and succinate dehydrogenase, which are FAD-binding enzymes. For the flavoprotein subunit of succinate dehydrogenase we could demonstrate that this was not due to a changed level of mitochondrial FAD or to a change in the degree of flavinylation of the protein. Instead, the amount of the flavoprotein subunit of succinate dehydrogenase was strongly reduced, indicating an additional regulatory role for Flx1p in protein synthesis or degradation.
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Affiliation(s)
- Valeria Bafunno
- Dipartimento di Biochimica e Biologia Molecolare, Università di Bari, Via Orabona 4, Bari, Italy
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Gargus JJ, Boyle K, Bocian M, Roe DS, Vianey-Saban C, Roe CR. Respiratory complex II defect in siblings associated with a symptomatic secondary block in fatty acid oxidation. J Inherit Metab Dis 2003; 26:659-70. [PMID: 14707514 DOI: 10.1023/b:boli.0000005659.52200.c1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The mitochondrial oxidative phosphorylation and fatty acid oxidation pathways have traditionally been considered independent major sources of cellular energy production; however, case reports of patients with specific enzymatic defects in either pathway have suggested the potential for a complex interference between the two. This study documents a new site of interference between the two pathways, a site in respiratory complex II capable of producing clinical signs of a block in fatty acid oxidation and reduced in vitro activity of acyl-CoA dehydrogenases. The initial patient, and later her newborn sibling, had mildly dysmorphic features, lactic acidosis and a defect in mitochondrial respiratory complex II associated with many biochemical features of a block in fatty acid oxidation. Results of in vitro probing of intact fibroblasts from both patients with methyl[2H3]palmitate and L-carnitine revealed greatly increased [2H3]butyrylcarnitine; however, the ratio of dehydrogenase activity with butyryl-CoA with anti-MCAD inactivating antibody (used to reveal SCAD-specific activity) to that with octanoyl-CoA was normal, excluding a selective SCAD or MCAD deficiency. Respiratory complex II was defective in both patients, with an absent thenoyltrifluoroacetone-sensitive succinate Q reductase activity that was partially restored by supplementation with duroquinone. Although secondary, the block in fatty acid oxidation was a major management problem since attempts to provide essential fatty acids precipitated acidotic decompensations. This study reinforces the need to pursue broadly the primary genetic defect within these two pathways, making full use of increasingly available functional and molecular diagnostic tools.
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Affiliation(s)
- J J Gargus
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697-4034, USA.
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Affiliation(s)
- Kailash C Bhuyan
- Membrane Biochemistry Laboratory, Department of Ophthalmology, Columbia University, New York, New York 10032, USA
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Prelack K, Sheridan RL. Micronutrient supplementation in the critically ill patient: strategies for clinical practice. THE JOURNAL OF TRAUMA 2001; 51:601-20. [PMID: 11535921 DOI: 10.1097/00005373-200109000-00037] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- K Prelack
- Burn and Trauma Services, Massachusetts General Hospital , 55 Fruit Street, Boston, MA 02114, USA
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Rodríguez-Meléndez R, Cano S, Méndez ST, Velázquez A. Biotin regulates the genetic expression of holocarboxylase synthetase and mitochondrial carboxylases in rats. J Nutr 2001; 131:1909-13. [PMID: 11435506 DOI: 10.1093/jn/131.7.1909] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Biotin is the cofactor of carboxylases [pyruvate (PC), propionyl-CoA (PCC), 3-methyl crotonyl-CoA and acetyl-CoA], to which it is covalently bound by the action of holocarboxylase synthetase (HCS). We have studied whether biotin also regulates their expression, as it does other, nonrelated enzymes (e.g., glucokinase, phosphoenol pyruvate carboxykinase, guanylate cyclase). For this purpose, HCS, PC and PCC mRNAs were studied in biotin-deficient rat liver, kidney, muscle and brain of biotin-deficient rats. PC- and PCC-specific activities and protein masses were also measured. The 24-h time course of HCS mRNA in deficient rats was examined after biotin supplementation. HCS mRNA was significantly reduced during vitamin deficiency. It increased in deficient rats after biotin was injected, reaching control levels 24 h after administration. These changes seem to be the first known instance in mammals of an effect of a water-soluble vitamin on a mRNA functionally related to it. In contrast, the decreased activities of the carboxylases were associated with reductions in the amounts of their enzyme proteins except in brain. However, their mRNA levels were not affected. There are no reports on these types of vitamin affecting the mRNA or protein levels of their apoenzymes or their products. This work provides evidence for biotin being a modulator of the genetic expression of the enzymes involved in its function as a cofactor. As such, it may be a useful model for probing a similar role for other water-soluble vitamins.
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Affiliation(s)
- R Rodríguez-Meléndez
- Unidad de Genética de la Nutrición of the Instituto de Investigaciones Biomédicas, UNAM and Instituto Nacional de Pediatría, México DF 04530
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Barile M, Brizio C, Valenti D, De Virgilio C, Passarella S. The riboflavin/FAD cycle in rat liver mitochondria. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:4888-900. [PMID: 10903524 DOI: 10.1046/j.1432-1327.2000.01552.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Here we provide evidence that mitochondria isolated from rat liver can synthesize FAD from riboflavin that has been taken up and from endogenous ATP. Riboflavin uptake takes place via a carrier-mediated process, as shown by the inverse relationship between fold accumulation and riboflavin concentration, the saturation kinetics [riboflavin Km and Vmax values were 4.4+/-1.3 microM and 35+/-5 pmol x min(-1) (mg protein)(-1), respectively] and the inhibition shown by the thiol reagent mersalyl, which cannot enter the mitochondria. FAD synthesis is due to the existence of FAD synthetase (EC 2.7.7.2), localized in the matrix, which has as a substrate pair mitochondrial ATP and FMN synthesized from taken up riboflavin via the putative mitochondrial riboflavin kinase. In the light of certain features, including the protein thermal stability and molecular mass, mitochondrial FAD synthetase differs from the cytosolic isoenzyme. Apparent Km and apparent Vmax values for FMN were 5.4+/-0.9 microM and 22.9+/-1.4 pmol x min(-1) x (mg matrix protein)(-1), respectively. Newly synthesized FAD inside the mitochondria can be exported from the mitochondria in a manner sensitive to atractyloside but insensitive to mersalyl. The occurrence of the riboflavin/FAD cycle is proposed to account for riboflavin uptake in mitochondria biogenesis and riboflavin recovery in mitochondrial flavoprotein degradation; both are prerequisites for the synthesis of mitochondrial flavin cofactors.
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Affiliation(s)
- M Barile
- Dipartimento di Biochimica e Biologia Molecolare, Università di Bari, and Centro di Studio sui Mitocondri e Metabolismo Energetico, Bari, C.N.R., Italy.
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Brizio C, Otto A, Brandsch R, Passarella S, Barile M. A protein factor of rat liver mitochondrial matrix involved in flavinylation of dimethylglycine dehydrogenase. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:4346-54. [PMID: 10880957 DOI: 10.1046/j.1432-1327.2000.01464.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The involvement of rat liver mitochondria in the flavinylation of the mitochondrial matrix flavoenzyme dimethylglycine dehydrogenase (Me2GlyDH) has been investigated. Me2GlyDH was synthesized as an apoenzyme in the rabbit reticulocyte lysate (RL) transcription/translation system and its flavinylation was monitored by virtue of the trypsin resistance of the holoenzyme. The rate of holoenzyme formation in the presence of FAD was stimulated with increasing efficiency by the addition of solubilized mitoplasts, mitochondrial matrix and DEAE-purified matrix fraction. Apo-Me2GlyDH was also converted into holoenzyme when the solubilized mitoplasts were supplemented with FMN and ATP. This observation is consistent with the existence of a mitochondrial FAD synthetase generating the FAD needed for holoenzyme formation from its precursors. Holoenzyme formation in the presence of FAD increased linearly with the concentration of matrix protein in the assay, and depended on the amount of externally added Me2GlyDH with saturation characteristics. These findings suggest the presence of a protein factor in the mitochondrial matrix which stimulates Me2GlyDH flavinylation. This factor was different from both mitochondrial heat shock protein (Hsp)70, as shown by immunodepletion experiments, and mitochondrial Hsp60, as demonstrated by the capability of a DEAE-purified matrix fraction devoid of Hsp60 to accelerate flavinylation of both RL translated and purified Me2GlyDH.
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Affiliation(s)
- C Brizio
- Dipartimento di Biochimica e Biologia Molecolare, Università di Bari, Italy
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Nagao M, Kibayashi M, Chiba S. Effect of valproic acid on the expression of acyl-CoA dehydrogenases in various tissues. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2000; 466:177-89. [PMID: 10709642 DOI: 10.1007/0-306-46818-2_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- M Nagao
- Department of Pediatrics, National Otaru Hospital, Hokkaido, Japan.
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Brijlal S, Lakshmi AV, Bamji MS. Mitochondrial oxidative metabolism during respiratory infection in riboflavin deficient mice. J Nutr Biochem 1999; 10:728-32. [PMID: 15539273 DOI: 10.1016/s0955-2863(99)00064-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/1999] [Accepted: 09/24/1999] [Indexed: 11/24/2022]
Abstract
Studies in children and mice have shown that respiratory infection alters riboflavin metabolism, resulting in increased urinary loss of this vitamin. This could be due to mobilization of riboflavin from the liver to blood because liver Flavin adenine dinucleotide (FAD) levels were lowered in the mice during infection. To understand the functional implications of lowered hepatic FAD levels during respiratory infection, flavoprotein functions such as oxidative phosphorylation and beta-oxidation of the liver mitochondria were examined during infection in mice. Weanling mice were fed either riboflavin-restricted or control diet for 18 days and then injected with a sublethal dose of Klebsiella pneumoniae. During infection, the state 3 respiratory rate with palmitoyl-L-carnitine and glutamate were significantly lowered (27-29%) in the riboflavin-restricted group, whereas in the control group 10% reduction was observed with palmitoyl-L-carnitine as substrate. A 22% reduction in the respiratory control ratio with palmitoyl-L-carnitine as substrate was observed during infection in the riboflavin-restricted group. The beta-oxidation of palmitoyl-L-carnitine was significantly lowered (29%) in the riboflavin-restricted infected group. The results of the study suggest that the effects of infection on vital physiologic functions were more pronounced in the riboflavin-restricted mice than in the control mice.
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Affiliation(s)
- S Brijlal
- National Institute of Nutrition, Indian Council of Medical Research, Jamai Osmania, Hyderabad, India
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