1
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Gougeard N, Sancho-Vaello E, Fernández-Murga ML, Martínez-Sinisterra B, Loukili-Hassani B, Häberle J, Marco-Marín C, Rubio V. Use of pure recombinant human enzymes to assess the disease-causing potential of missense mutations in urea cycle disorders, applied to N-acetylglutamate synthase deficiency. J Inherit Metab Dis 2024. [PMID: 38740568 DOI: 10.1002/jimd.12747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 04/21/2024] [Accepted: 04/23/2024] [Indexed: 05/16/2024]
Abstract
N-acetylglutamate synthase (NAGS) makes acetylglutamate, the essential activator of the first, regulatory enzyme of the urea cycle, carbamoyl phosphate synthetase 1 (CPS1). NAGS deficiency (NAGSD) and CPS1 deficiency (CPS1D) present identical phenotypes. However, they must be distinguished, because NAGSD is cured by substitutive therapy with the N-acetyl-L-glutamate analogue N-carbamyl-L-glutamate, while curative therapy of CPS1D requires liver transplantation. Since their differentiation is done genetically, it is important to ascertain the disease-causing potential of CPS1 and NAGS genetic variants. With this goal, we previously carried out site-directed mutagenesis studies with pure recombinant human CPS1. We could not do the same with human NAGS (HuNAGS) because of enzyme instability, leading to our prior utilization of a bacterial NAGS as an imperfect surrogate of HuNAGS. We now use genuine HuNAGS, stabilized as a chimera of its conserved domain (cHuNAGS) with the maltose binding protein (MBP), and produced in Escherichia coli. MBP-cHuNAGS linker cleavage allowed assessment of the enzymatic properties and thermal stability of cHuNAGS, either wild-type or hosting each one of 23 nonsynonymous single-base changes found in NAGSD patients. For all but one change, disease causation was accounted by the enzymatic alterations identified, including, depending on the variant, loss of arginine activation, increased Km Glutamate, active site inactivation, decreased thermal stability, and protein misfolding. Our present approach outperforms experimental in vitro use of bacterial NAGS or in silico utilization of prediction servers (including AlphaMissense), illustrating with HuNAGS the value for UCDs of using recombinant enzymes for assessing disease-causation and molecular pathogenesis, and for therapeutic guidance.
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Affiliation(s)
- Nadine Gougeard
- Instituto de Biomedicina de Valencia, IBV-CSIC, Valencia, Spain
- Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras, (CIBERER-ISCIII) at the IBV-CSIC, Valencia, Spain
| | | | | | | | | | - Johannes Häberle
- University Children's Hospital Zurich and Children's Research Centre, Zurich, Switzerland
| | - Clara Marco-Marín
- Instituto de Biomedicina de Valencia, IBV-CSIC, Valencia, Spain
- Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras, (CIBERER-ISCIII) at the IBV-CSIC, Valencia, Spain
| | - Vicente Rubio
- Instituto de Biomedicina de Valencia, IBV-CSIC, Valencia, Spain
- Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras, (CIBERER-ISCIII) at the IBV-CSIC, Valencia, Spain
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2
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Kakiuchi T, Nosho T, Oka M, Tashiro K. Hyperammonemia in a carbamoyl-phosphate synthetase 1 deficiency recipient after living-donor liver transplantation from a carrier donor: a case report. Front Med (Lausanne) 2024; 10:1327854. [PMID: 38235270 PMCID: PMC10792046 DOI: 10.3389/fmed.2023.1327854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/13/2023] [Indexed: 01/19/2024] Open
Abstract
Carbamoyl-phosphate synthetase 1 (CPS1) deficiency is an autosomal recessive congenital urea cycle disorder (UCD) characterized by hyperammonemia. The recipients of liver transplantation (LT) for UCD are often children, and the potential donors are often the parents. Hereditary congenital diseases involving UCD entail the possibility of both parents being genetically heterozygous. Herein, we describe the case of a 12-year-old girl with CPS1 deficiency receiving a liver transplant (soon after birth) from her father, who had a heterozygous CPS1 mutation. She was referred to our hospital with respiratory distress after contracting two infections (respiratory syncytial virus and human metapneumovirus) within a short period, both of which presented with hyperammonemia. Medication for hyperammonemia quickly lowered the ammonia levels. The hyperammonemia was thought to be caused by the heterozygous mutation in the donor liver; moreover, it is likely that the low enzyme activity in the patient's liver was increased due to the infections. This is the first study to report hyperammonemia in a CPS1 deficiency patient due to an infection after LT. Thus, patients with CPS1 deficiency should be aware of the development of hyperammonemia after LT.
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Affiliation(s)
- Toshihiko Kakiuchi
- Department of Pediatrics, Faculty of Medicine, Saga University, Saga, Japan
| | - Tetsuya Nosho
- Department of Pediatrics, Faculty of Medicine, Saga University, Saga, Japan
| | - Masafumi Oka
- Department of Pediatrics, Faculty of Medicine, Saga University, Saga, Japan
| | - Katsuya Tashiro
- Department of Pediatrics, Karatsu Red Cross Hospital, Karatsu, Japan
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3
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Ruocco C, Malavazos AE, Ragni M, Carruba MO, Valerio A, Iacobellis G, Nisoli E. Amino acids contribute to adaptive thermogenesis. New insights into the mechanisms of action of recent drugs for metabolic disorders are emerging. Pharmacol Res 2023; 195:106892. [PMID: 37619907 DOI: 10.1016/j.phrs.2023.106892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 07/28/2023] [Accepted: 08/17/2023] [Indexed: 08/26/2023]
Abstract
Adaptive thermogenesis is the heat production by muscle contractions (shivering thermogenesis) or brown adipose tissue (BAT) and beige fat (non-shivering thermogenesis) in response to external stimuli, including cold exposure. BAT and beige fat communicate with peripheral organs and the brain through a variegate secretory and absorption processes - controlling adipokines, microRNAs, extracellular vesicles, and metabolites - and have received much attention as potential therapeutic targets for managing obesity-related disorders. The sympathetic nervous system and norepinephrine-releasing adipose tissue macrophages (ATM) activate uncoupling protein 1 (UCP1), expressed explicitly in brown and beige adipocytes, dissolving the electrochemical gradient and uncoupling tricarboxylic acid cycle and the electron transport chain from ATP production. Mounting evidence has attracted attention to the multiple effects of dietary and endogenously synthesised amino acids in BAT thermogenesis and metabolic phenotype in animals and humans. However, the mechanisms implicated in these processes have yet to be conclusively characterized. In the present review article, we aim to define the principal investigation areas in this context, including intestinal microbiota constitution, adipose autophagy modulation, and secretome and metabolic fluxes control, which lead to increased brown/beige thermogenesis. Finally, also based on our recent epicardial adipose tissue results, we summarise the evidence supporting the notion that the new dual and triple agonists of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon (GCG) receptor - with never before seen weight loss and insulin-sensitizing efficacy - promote thermogenic-like amino acid profiles in BAT with robust heat production and likely trigger sympathetic activation and adaptive thermogenesis by controlling amino acid metabolism and ATM expansion in BAT and beige fat.
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Affiliation(s)
- Chiara Ruocco
- Center for Study and Research on Obesity, Department of Biomedical Technology and Translational Medicine, University of Milan, via Vanvitelli, 32, 20129 Milan, Italy
| | - Alexis Elias Malavazos
- Endocrinology Unit, Clinical Nutrition and Cardiovascular Prevention Service, IRCCS Policlinico San Donato, Piazza Edmondo Malan, 2, San Donato Milanese, 20097 Milan, Italy; Department of Biomedical, Surgical and Dental Sciences, University of Milan, via della Commenda, 10, 20122 Milan, Italy
| | - Maurizio Ragni
- Center for Study and Research on Obesity, Department of Biomedical Technology and Translational Medicine, University of Milan, via Vanvitelli, 32, 20129 Milan, Italy
| | - Michele O Carruba
- Center for Study and Research on Obesity, Department of Biomedical Technology and Translational Medicine, University of Milan, via Vanvitelli, 32, 20129 Milan, Italy
| | - Alessandra Valerio
- Department of Molecular and Translational Medicine, University of Brescia, viale Europa, 11, 25123 Brescia, Italy
| | - Gianluca Iacobellis
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami, 1400 NW 12th Ave, Miami, FL, USA
| | - Enzo Nisoli
- Center for Study and Research on Obesity, Department of Biomedical Technology and Translational Medicine, University of Milan, via Vanvitelli, 32, 20129 Milan, Italy.
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4
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Gonzalez B, Tare A, Ryu S, Johnson SC, Atzmon G, Barzilai N, Kaeberlein M, Suh Y. High-throughput sequencing analysis of nuclear-encoded mitochondrial genes reveals a genetic signature of human longevity. GeroScience 2023; 45:311-330. [PMID: 35948858 PMCID: PMC9886794 DOI: 10.1007/s11357-022-00634-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 07/28/2022] [Indexed: 02/03/2023] Open
Abstract
Mitochondrial dysfunction is a well-known contributor to aging and age-related diseases. The precise mechanisms through which mitochondria impact human lifespan, however, remain unclear. We hypothesize that humans with exceptional longevity harbor rare variants in nuclear-encoded mitochondrial genes (mitonuclear genes) that confer resistance against age-related mitochondrial dysfunction. Here we report an integrated functional genomics study to identify rare functional variants in ~ 660 mitonuclear candidate genes discovered by target capture sequencing analysis of 496 centenarians and 572 controls of Ashkenazi Jewish descent. We identify and prioritize longevity-associated variants, genes, and mitochondrial pathways that are enriched with rare variants. We provide functional gene variants such as those in MTOR (Y2396Lfs*29), CPS1 (T1406N), and MFN2 (G548*) as well as LRPPRC (S1378G) that is predicted to affect mitochondrial translation. Taken together, our results suggest a functional role for specific mitonuclear genes and pathways in human longevity.
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Affiliation(s)
- Brenda Gonzalez
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Archana Tare
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Seungjin Ryu
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Pharmacology, College of Medicine, Hallym University, Chuncheon, Gangwon, 24252, Republic of Korea
| | - Simon C Johnson
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Gil Atzmon
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Nir Barzilai
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA, 98195, USA
| | - Yousin Suh
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
- Departments of Obstetrics and Gynecology, and Genetics and Development, Columbia University, 630 West 168th Street, New York, NY, 10032, USA.
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5
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Unraveling the therapeutic potential of carbamoyl phosphate synthetase 1 (CPS1) in human disease. Bioorg Chem 2022; 130:106253. [DOI: 10.1016/j.bioorg.2022.106253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/23/2022] [Accepted: 11/01/2022] [Indexed: 11/07/2022]
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6
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Surendran P, Stewart ID, Au Yeung VPW, Pietzner M, Raffler J, Wörheide MA, Li C, Smith RF, Wittemans LBL, Bomba L, Menni C, Zierer J, Rossi N, Sheridan PA, Watkins NA, Mangino M, Hysi PG, Di Angelantonio E, Falchi M, Spector TD, Soranzo N, Michelotti GA, Arlt W, Lotta LA, Denaxas S, Hemingway H, Gamazon ER, Howson JMM, Wood AM, Danesh J, Wareham NJ, Kastenmüller G, Fauman EB, Suhre K, Butterworth AS, Langenberg C. Rare and common genetic determinants of metabolic individuality and their effects on human health. Nat Med 2022; 28:2321-2332. [PMID: 36357675 PMCID: PMC9671801 DOI: 10.1038/s41591-022-02046-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 09/16/2022] [Indexed: 11/12/2022]
Abstract
Garrod's concept of 'chemical individuality' has contributed to comprehension of the molecular origins of human diseases. Untargeted high-throughput metabolomic technologies provide an in-depth snapshot of human metabolism at scale. We studied the genetic architecture of the human plasma metabolome using 913 metabolites assayed in 19,994 individuals and identified 2,599 variant-metabolite associations (P < 1.25 × 10-11) within 330 genomic regions, with rare variants (minor allele frequency ≤ 1%) explaining 9.4% of associations. Jointly modeling metabolites in each region, we identified 423 regional, co-regulated, variant-metabolite clusters called genetically influenced metabotypes. We assigned causal genes for 62.4% of these genetically influenced metabotypes, providing new insights into fundamental metabolite physiology and clinical relevance, including metabolite-guided discovery of potential adverse drug effects (DPYD and SRD5A2). We show strong enrichment of inborn errors of metabolism-causing genes, with examples of metabolite associations and clinical phenotypes of non-pathogenic variant carriers matching characteristics of the inborn errors of metabolism. Systematic, phenotypic follow-up of metabolite-specific genetic scores revealed multiple potential etiological relationships.
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Affiliation(s)
- Praveen Surendran
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
- British Heart Foundation Centre of Research Excellence, School of Clinical Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
- Health Data Research UK Cambridge, Wellcome Genome Campus and University of Cambridge, Hinxton, UK
- Rutherford Fund Fellow, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
| | | | | | - Maik Pietzner
- MRC Epidemiology Unit, University of Cambridge, Cambridge, UK
- Computational Medicine, Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Johannes Raffler
- Institute of Computational Biology, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
- Digital Medicine, University Hospital of Augsburg, Augsburg, Germany
| | - Maria A Wörheide
- Institute of Computational Biology, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | - Chen Li
- MRC Epidemiology Unit, University of Cambridge, Cambridge, UK
| | - Rebecca F Smith
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
| | - Laura B L Wittemans
- MRC Epidemiology Unit, University of Cambridge, Cambridge, UK
- Big Data Institute, University of Oxford, Oxford, UK
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, UK
| | - Lorenzo Bomba
- Department of Human Genetics, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
- Open Targets, Wellcome Genome Campus, Hinxton, UK
| | - Cristina Menni
- Department of Twin Research & Genetic Epidemiology, King's College London, London, UK
| | - Jonas Zierer
- Department of Twin Research & Genetic Epidemiology, King's College London, London, UK
| | - Niccolò Rossi
- Department of Twin Research & Genetic Epidemiology, King's College London, London, UK
| | | | | | - Massimo Mangino
- Department of Twin Research & Genetic Epidemiology, King's College London, London, UK
- NIHR Biomedical Research Centre at Guy's and St Thomas' Foundation Trust, London, UK
| | - Pirro G Hysi
- Department of Twin Research & Genetic Epidemiology, King's College London, London, UK
| | - Emanuele Di Angelantonio
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
- British Heart Foundation Centre of Research Excellence, School of Clinical Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
- Health Data Research UK Cambridge, Wellcome Genome Campus and University of Cambridge, Hinxton, UK
- NIHR Blood and Transplant Research Unit in Donor Health and Genomics, University of Cambridge, Cambridge, UK
- Health Data Science Research Centre, Human Technopole, Milan, Italy
| | - Mario Falchi
- Department of Twin Research & Genetic Epidemiology, King's College London, London, UK
| | - Tim D Spector
- Department of Twin Research & Genetic Epidemiology, King's College London, London, UK
| | - Nicole Soranzo
- British Heart Foundation Centre of Research Excellence, School of Clinical Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
- Department of Human Genetics, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
- Open Targets, Wellcome Genome Campus, Hinxton, UK
- NIHR Blood and Transplant Research Unit in Donor Health and Genomics, University of Cambridge, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
| | | | - Wiebke Arlt
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
- NIHR Birmingham Biomedical Research Centre, University Hospitals Birmingham NHS Foundation Trust and University of Birmingham, Birmingham, UK
| | - Luca A Lotta
- MRC Epidemiology Unit, University of Cambridge, Cambridge, UK
| | - Spiros Denaxas
- Institute of Health Informatics, University College London, London, UK
- Health Data Research UK, London, UK
- British Heart Foundation Data Science Centre, London, UK
| | - Harry Hemingway
- Institute of Health Informatics, University College London, London, UK
- Health Data Research UK, London, UK
| | - Eric R Gamazon
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN, USA
- Clare Hall & MRC Epidemiology Unit, University of Cambridge, Cambridge, UK
| | - Joanna M M Howson
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
- Department of Genetics, Novo Nordisk Research Centre Oxford, Oxford, UK
| | - Angela M Wood
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
- British Heart Foundation Centre of Research Excellence, School of Clinical Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
- Health Data Research UK Cambridge, Wellcome Genome Campus and University of Cambridge, Hinxton, UK
- NIHR Blood and Transplant Research Unit in Donor Health and Genomics, University of Cambridge, Cambridge, UK
- MRC Biostatistics Unit, Cambridge Institute of Public Health, University of Cambridge, Cambridge, UK
- The Alan Turing Institute, London, UK
| | - John Danesh
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
- British Heart Foundation Centre of Research Excellence, School of Clinical Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
- Health Data Research UK Cambridge, Wellcome Genome Campus and University of Cambridge, Hinxton, UK
- Department of Human Genetics, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
- NIHR Blood and Transplant Research Unit in Donor Health and Genomics, University of Cambridge, Cambridge, UK
| | - Nicholas J Wareham
- Health Data Research UK Cambridge, Wellcome Genome Campus and University of Cambridge, Hinxton, UK
- MRC Epidemiology Unit, University of Cambridge, Cambridge, UK
| | - Gabi Kastenmüller
- Institute of Computational Biology, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | - Eric B Fauman
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development and Medical, Cambridge, MA, USA
| | - Karsten Suhre
- Department of Biophysics and Physiology, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Adam S Butterworth
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.
- British Heart Foundation Centre of Research Excellence, School of Clinical Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK.
- Health Data Research UK Cambridge, Wellcome Genome Campus and University of Cambridge, Hinxton, UK.
- NIHR Blood and Transplant Research Unit in Donor Health and Genomics, University of Cambridge, Cambridge, UK.
| | - Claudia Langenberg
- MRC Epidemiology Unit, University of Cambridge, Cambridge, UK.
- Computational Medicine, Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany.
- Precision Healthcare University Research Institute, Queen Mary University of London, London, UK.
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7
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Haskins N, Bhuvanendran S, Anselmi C, Gams A, Kanholm T, Kocher KM, LoTempio J, Krohmaly KI, Sohai D, Stearrett N, Bonner E, Tuchman M, Morizono H, Jaiswal JK, Caldovic L. Mitochondrial Enzymes of the Urea Cycle Cluster at the Inner Mitochondrial Membrane. Front Physiol 2021; 11:542950. [PMID: 33551825 PMCID: PMC7860981 DOI: 10.3389/fphys.2020.542950] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 12/09/2020] [Indexed: 01/13/2023] Open
Abstract
Mitochondrial enzymes involved in energy transformation are organized into multiprotein complexes that channel the reaction intermediates for efficient ATP production. Three of the mammalian urea cycle enzymes: N-acetylglutamate synthase (NAGS), carbamylphosphate synthetase 1 (CPS1), and ornithine transcarbamylase (OTC) reside in the mitochondria. Urea cycle is required to convert ammonia into urea and protect the brain from ammonia toxicity. Urea cycle intermediates are tightly channeled in and out of mitochondria, indicating that efficient activity of these enzymes relies upon their coordinated interaction with each other, perhaps in a cluster. This view is supported by mutations in surface residues of the urea cycle proteins that impair ureagenesis in the patients, but do not affect protein stability or catalytic activity. We find the NAGS, CPS1, and OTC proteins in liver mitochondria can associate with the inner mitochondrial membrane (IMM) and can be co-immunoprecipitated. Our in-silico analysis of vertebrate NAGS proteins, the least abundant of the urea cycle enzymes, identified a protein-protein interaction region present only in the mammalian NAGS protein—“variable segment,” which mediates the interaction of NAGS with CPS1. Use of super resolution microscopy showed that NAGS, CPS1 and OTC are organized into clusters in the hepatocyte mitochondria. These results indicate that mitochondrial urea cycle proteins cluster, instead of functioning either independently or in a rigid multienzyme complex.
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Affiliation(s)
- Nantaporn Haskins
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, United States
| | - Shivaprasad Bhuvanendran
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, United States
| | - Claudio Anselmi
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, United States.,Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, United States
| | - Anna Gams
- Department of Biomedical Engineering, School of Engineering and Applied Sciences, The George Washington University, Washington, DC, United States
| | - Tomas Kanholm
- School of Medicine and Health Sciences, Institute for Biomedical Sciences, The George Washington University, Washington, DC, United States
| | - Kristen M Kocher
- School of Medicine and Health Sciences, Institute for Biomedical Sciences, The George Washington University, Washington, DC, United States
| | - Jonathan LoTempio
- School of Medicine and Health Sciences, Institute for Biomedical Sciences, The George Washington University, Washington, DC, United States
| | - Kylie I Krohmaly
- School of Medicine and Health Sciences, Institute for Biomedical Sciences, The George Washington University, Washington, DC, United States
| | - Danielle Sohai
- School of Medicine and Health Sciences, Institute for Biomedical Sciences, The George Washington University, Washington, DC, United States
| | - Nathaniel Stearrett
- School of Medicine and Health Sciences, Institute for Biomedical Sciences, The George Washington University, Washington, DC, United States.,Computational Biology Institute, Milken Institute School of Public Health, The George Washington University, Washington, DC, United States
| | - Erin Bonner
- School of Medicine and Health Sciences, Institute for Biomedical Sciences, The George Washington University, Washington, DC, United States
| | - Mendel Tuchman
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, United States
| | - Hiroki Morizono
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, United States.,Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, United States
| | - Jyoti K Jaiswal
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, United States.,Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, United States
| | - Ljubica Caldovic
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, United States.,Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, United States
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8
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McGowan M, Ferreira C, Whitehead M, Basu SK, Chang T, Gropman A. The Application of Neurodiagnostic Studies to Inform the Acute Management of a Newborn Presenting With Sarbamoyl Shosphate Synthetase 1 Deficiency. Child Neurol Open 2021; 8:2329048X20985179. [PMID: 33644249 PMCID: PMC7841664 DOI: 10.1177/2329048x20985179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 11/14/2020] [Accepted: 12/06/2020] [Indexed: 11/17/2022] Open
Abstract
Neonatal-onset urea cycle disorders (UCDs) may result in hyperammonemic (HA) encephalopathy presenting with several neurologic sequelae including seizures, coma, and death. However, no recommendations are given in how and when neurodiagnostic studies should be used to screen or assess for these neurologic complications. We present a case of carbamoyl phosphate synthetase 1 (CPS1) deficiency in a newborn female in which electroencephalogram monitoring to assess encephalopathy and seizures, and magnetic resonance imaging measurements of brain metabolites were used to guide care during her hyperammonemic crisis. Her neurologic course and response to treatment characterizes the significant neurologic impact of HA encephalopathy. Our group herein proposes a clinical neurodiagnostic pathway for managing acute HA encephalopathy.
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Affiliation(s)
- Meaghan McGowan
- University of Illinois College of Medicine, Chicago, IL,
USA
| | - Carlos Ferreira
- Medical Genomics and Metabolic Genetics Branch, National
Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Matthew Whitehead
- Neuroradiology, Children’s National Hospital, George
Washington University School of Medicine, Washington, DC, USA
| | - Sudeepta K. Basu
- Neonatology, Children’s National Hospital, George Washington
University School of Medicine, Washington, DC, USA
| | - Taeun Chang
- Neurology, Children’s National Hospital, George Washington
University School of Medicine, Washington, DC, USA
| | - Andrea Gropman
- Neurology, Children’s National Hospital, George Washington
University School of Medicine, Washington, DC, USA
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9
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Makris G, Lauber M, Rüfenacht V, Gemperle C, Diez-Fernandez C, Caldovic L, Froese DS, Häberle J. Clinical and structural insights into potential dominant negative triggers of proximal urea cycle disorders. Biochimie 2020; 183:89-99. [PMID: 33309754 DOI: 10.1016/j.biochi.2020.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 12/04/2020] [Accepted: 12/08/2020] [Indexed: 12/31/2022]
Abstract
Despite biochemical and genetic testing being the golden standards for identification of proximal urea cycle disorders (UCDs), genotype-phenotype correlations are often unclear. Co-occurring partial defects affecting more than one gene have not been demonstrated so far in proximal UCDs. Here, we analyzed the mutational spectrum of 557 suspected proximal UCD individuals. We probed oligomerizing forms of NAGS, CPS1 and OTC, and evaluated the surface exposure of residues mutated in heterozygously affected individuals. BN-PAGE and gel-filtration chromatography were employed to discover protein-protein interactions within recombinant enzymes. From a total of 281 confirmed patients, only 15 were identified as "heterozygous-only" candidates (i.e. single defective allele). Within these cases, the only missense variants to potentially qualify as dominant negative triggers were CPS1 p.Gly401Arg and NAGS p.Thr181Ala and p.Tyr512Cys, as assessed by residue oligomerization capacity and surface exposure. However, all three candidates seem to participate in critical intramolecular functions, thus, unlikely to facilitate protein-protein interactions. This interpretation is further supported by BN-PAGE and gel-filtration analyses revealing no multiprotein proximal urea cycle complex formation. Collectively, genetic analysis, structural considerations and in vitro experiments point against a prominent role of dominant negative effects in human proximal UCDs.
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Affiliation(s)
- Georgios Makris
- Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Matthias Lauber
- Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Véronique Rüfenacht
- Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Corinne Gemperle
- Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Carmen Diez-Fernandez
- Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland; Nextech Invest, Bahnhofstrasse 18, 8001, Zurich, Switzerland
| | - Ljubica Caldovic
- Center for Genetic Medicine Research, Children's National Hospital, Washington, DC, USA
| | - D Sean Froese
- Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Johannes Häberle
- Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.
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10
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Liu C, Ren Y, Li Z, Hu Q, Yin L, Wang H, Qiao X, Zhang Y, Xing L, Xi Y, Jiang F, Wang S, Huang C, Liu B, Liu H, Wan F, Qian W, Fan W. Giant African snail genomes provide insights into molluscan whole-genome duplication and aquatic-terrestrial transition. Mol Ecol Resour 2020; 21:478-494. [PMID: 33000522 DOI: 10.1111/1755-0998.13261] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 09/03/2020] [Accepted: 09/07/2020] [Indexed: 12/15/2022]
Abstract
Whole-genome duplication (WGD), contributing to evolutionary diversity and environmental adaptability, has been observed across a wide variety of eukaryotic groups, but not in molluscs. Molluscs are the second largest animal phylum in terms of species numbers, and among the organisms that have successfully adapted to the nonmarine realm through aquatic-terrestrial (A-T) transition. We assembled a chromosome-level reference genome for Achatina immaculata, a globally invasive species, and compared the genomes of two giant African snails (A. immaculata and Achatina fulica) to other available mollusc genomes. Macrosynteny, colinearity blocks, Ks peak and Hox gene clusters collectively suggested a WGD event in the two snails. The estimated WGD timing (~70 million years ago) was close to the speciation age of the Sigmurethra-Orthurethra (within Stylommatophora) lineage and the Cretaceous-Tertiary (K-T) mass extinction, indicating that the WGD may have been a common event shared by all Sigmurethra-Orthurethra species and conferred ecological adaptability allowing survival after the K-T extinction event. Furthermore, the adaptive mechanism of WGD in terrestrial ecosystems was confirmed by the presence of gene families related to the respiration, aestivation and immune defence. Several mucus-related gene families expanded early in the Stylommatophora lineage, and the haemocyanin and phosphoenolpyruvate carboxykinase families doubled during WGD, and zinc metalloproteinase genes were highly tandemly duplicated after WGD. This evidence suggests that although WGD may not have been the direct driver of the A-T transition, it played an important part in the terrestrial adaptation of giant African snails.
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Affiliation(s)
- Conghui Liu
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Yuwei Ren
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Zaiyuan Li
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Qi Hu
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Lijuan Yin
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Hengchao Wang
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Xi Qiao
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Yan Zhang
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Longsheng Xing
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Yu Xi
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Fan Jiang
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Sen Wang
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Cong Huang
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Bo Liu
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Hangwei Liu
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Fanghao Wan
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Wanqiang Qian
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Wei Fan
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
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11
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The Application of Next-Generation Sequencing (NGS) in Neonatal-Onset Urea Cycle Disorders (UCDs): Clinical Course, Metabolomic Profiling, and Genetic Findings in Nine Chinese Hyperammonemia Patients. BIOMED RESEARCH INTERNATIONAL 2020; 2020:5690915. [PMID: 32934962 PMCID: PMC7479453 DOI: 10.1155/2020/5690915] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/10/2020] [Accepted: 08/17/2020] [Indexed: 12/19/2022]
Abstract
During Jan. 2016–Dec. 2019, nine Chinese patients from eight unrelated families were diagnosed with neonatal-onset UCDs by targeted panel sequencing or whole-exome sequencing (WES). Their clinical manifestations, biochemical features, 180-day-age outcomes, and molecular genetic characteristics were reviewed retrospectively. NGS-based tests revealed 7 patients diagnosed with ornithine transcarbamylase deficiency (OTCD) and 2 with carbamoylphosphate synthetase I deficiency (CPS1D). The spectrum of the clinical presentation of nine affected individuals progressed from unspecific symptoms like poor feeding to somnolence, coma, and death. All patients presented with an acute hyperammonemia. The most robust metabolic pattern in OTCD was hyperglutaminemic hyperammonemia with high concentration of urine orotic acid, and it was reported in six patients. Of ten variants found on the OTC gene and CPS1 gene, 3 were novel: (c.176T>C (p.L59P)) in the OTC gene, c.2938G>A (p.G980S) and c.3734T>A (p.L1245H) in the CPS1 gene. There was a high mortality rate of 77.78% (7/9) for all the defects combined. An OTC-deficient male and a CPS1-deficient female survived from episodes of hyperammonemia. Although prompt recognition of UCD and the use of alternative pathway therapy in addition to provision of appropriate nutrition and dialysis improved survival, the overall outcomes for the neonatal-onset type are poor in China.
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12
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Galsgaard KD, Pedersen J, Kjeldsen SAS, Winther-Sørensen M, Stojanovska E, Vilstrup H, Ørskov C, Wewer Albrechtsen NJ, Holst JJ. Glucagon receptor signaling is not required for N-carbamoyl glutamate- and l-citrulline-induced ureagenesis in mice. Am J Physiol Gastrointest Liver Physiol 2020; 318:G912-G927. [PMID: 32174131 DOI: 10.1152/ajpgi.00294.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Glucagon regulates the hepatic amino acid metabolism and increases ureagenesis. Ureagenesis is activated by N-acetylglutamate (NAG), formed via activation of N-acetylglutamate synthase (NAGS). With the aim to identify the steps whereby glucagon both acutely and chronically regulates ureagenesis, we investigated whether glucagon receptor-mediated activation of ureagenesis is required in a situation where NAGS activity and/or NAG levels are sufficient to activate the first step of the urea cycle in vivo. Female C57BL/6JRj mice treated with a glucagon receptor antagonist (GRA), glucagon receptor knockout (Gcgr-/-) mice, and wild-type (Gcgr+/+) littermates received an intraperitoneal injection of N-carbamoyl glutamate (Car; a stable variant of NAG), l-citrulline (Cit), Car and Cit (Car + Cit), or PBS. In separate experiments, Gcgr-/- and Gcgr+/+ mice were administered N-carbamoyl glutamate and l-citrulline (wCar + wCit) in the drinking water for 8 wk. Car, Cit, and Car + Cit significantly (P < 0.05) increased plasma urea concentrations, independently of pharmacological and genetic disruption of glucagon receptor signaling (P = 0.9). Car increased blood glucose concentrations equally in GRA- and vehicle-treated mice (P = 0.9), whereas the increase upon Car + Cit was impaired in GRA-treated mice (P = 0.008). Blood glucose concentrations remained unchanged in Gcgr-/- mice upon Car (P = 0.2) and Car + Cit (P = 0.9). Eight weeks administration of wCar + wCit did not change blood glucose (P > 0.2), plasma amino acid (P > 0.4), and urea concentrations (P > 0.3) or the area of glucagon-positive cells (P > 0.3) in Gcgr-/- and Gcgr+/+ mice. Our data suggest that glucagon-mediated activation of ureagenesis is not required when NAGS activity and/or NAG levels are sufficient to activate the first step of the urea cycle.NEW & NOTEWORTHY Hepatic ureagenesis is essential in amino acid metabolism and is importantly regulated by glucagon, but the exact mechanism is unclear. With the aim to identify the steps whereby glucagon both acutely and chronically regulates ureagenesis, we here show, contrary to our hypothesis, that glucagon receptor-mediated activation of ureagenesis is not required when N-acetylglutamate synthase activity and/or N-acetylglutamate levels are sufficient to activate the first step of the urea cycle in vivo.
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Affiliation(s)
- Katrine D Galsgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Pedersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Endocrinology and Nephrology, Nordsjaellands Hospital Hilleroed, Hilleroed, Denmark
| | - Sasha A S Kjeldsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marie Winther-Sørensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Elena Stojanovska
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hendrik Vilstrup
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Cathrine Ørskov
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicolai J Wewer Albrechtsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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13
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Yan B, Wang C, Zhang K, Zhang H, Gao M, Lv Y, Li X, Liu Y, Gai Z. Novel Neonatal Variants of the Carbamoyl Phosphate Synthetase 1 Deficiency: Two Case Reports and Review of Literature. Front Genet 2019; 10:718. [PMID: 31507628 PMCID: PMC6713721 DOI: 10.3389/fgene.2019.00718] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 07/09/2019] [Indexed: 12/31/2022] Open
Abstract
Carbamoyl phosphate synthetase I (CPS1) deficiency (CPS1D), is a rare autosomal recessive disorder, characterized by life-threatening hyperammonemia. In this study, we presented the detailed clinical features and genetic analysis of two patients with neonatal-onset CPS1D carrying two compound heterozygous variants of c.1631C > T (p.T544M)/c.1981G > T (p.G661C), and c.2896G > T (p.E966X)/c622-3C > G in CPS1 gene, individually. Out of them, three variants are novel, unreported including a missense (c.1981G > T, p.G661C), a nonsense (c.2896G > T, p.E966X), and a splicing change of c.622-3C > G. We reviewed all available publications regarding CPS1 mutations, and in total 264 different variants have been reported, with majority of 157 (59.5%) missense, followed by 35 (13.2%) small deletions. This study expanded the mutational spectrum of CPS1. Moreover, our cases and review further support the idea that most (≥90%) of the mutations were "private" and only ∼10% recurred in unrelated families.
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Affiliation(s)
- Beibei Yan
- Neonatology Department, Qilu Children’s Hospital of Shandong University, Ji’nan, China
| | - Chao Wang
- Shandong Freshwater Fisheries Research Institute, Ji’nan, China
| | - Kaihui Zhang
- Pediatric Research Institute, Qilu Children’s Hospital of Shandong University, Ji’nan, China
| | - Haiyan Zhang
- Pediatric Research Institute, Qilu Children’s Hospital of Shandong University, Ji’nan, China
| | - Min Gao
- Pediatric Research Institute, Qilu Children’s Hospital of Shandong University, Ji’nan, China
| | - Yuqiang Lv
- Pediatric Research Institute, Qilu Children’s Hospital of Shandong University, Ji’nan, China
| | - Xiaoying Li
- Neonatology Department, Qilu Children’s Hospital of Shandong University, Ji’nan, China
| | - Yi Liu
- Pediatric Research Institute, Qilu Children’s Hospital of Shandong University, Ji’nan, China
| | - Zhongtao Gai
- Pediatric Research Institute, Qilu Children’s Hospital of Shandong University, Ji’nan, China
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14
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CPS1 T1405N polymorphism, HDL cholesterol, homocysteine and renal function are risk factors of VPA induced hyperammonemia among epilepsy patients. Epilepsy Res 2019; 154:139-143. [PMID: 31151073 DOI: 10.1016/j.eplepsyres.2019.05.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/07/2019] [Accepted: 05/17/2019] [Indexed: 01/15/2023]
Abstract
PURPOSE Valproic acid (VPA) is frequently used in the treatment of epilepsy. The adverse effects of VPA include hyperammonemia (HA) which is characterized by abnormally elevated blood ammonia level. Carbamoyl-Phosphate Synthase 1 (CPS1) is an enzyme catalyzing the initial step of removing ammonia from blood. Studies have demonstrated that the CPS1 polymorphism rs1047891-A allele carriers were susceptible to VPA-induced HA. However, the evidences remained controversial. In this study, we sought to validate the association between rs1047891 and VPA-induced HA by combining the association results from previous studies together. METHODS We first conducted a systematic meta-analysis to determine whether rs1047891 was statistically significant. Then, we further evaluated the pleiotropic effects of rs1047891 using published genome-wide association studies (GWAS) and UKBB results. A conditional analysis was conducted to investigate whether the association between rs1047891 and VPA-induced HA was mediated by cardiovascular or renal disease risk factors or vice versa. RESULTS The allelic, dominant and recessive ORs of rs1047891-A were all significant in our fixed-effect meta-analysis. In GWAS catalog and UKBB data, rs1047891 was associated with basal metabolic rate, adiposity and hematology traits, cardiovascular and renal disease risk factors. We further proved that plasma HDL cholesterol and homocysteine level, in addition to eGFR by serum creatinine, were associated with VPA-induced HA risk independently from rs1047891 polymorphism. CONCLUSION In conclusion, the SNP rs1047891 was associated with VPA-induce HA among epilepsy patients. Meanwhile, plasma HDL cholesterol and homocysteine level had independent effects from it.
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15
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Shi D, Caldovic L, Tuchman M. Sources and Fates of Carbamyl Phosphate: A Labile Energy-Rich Molecule with Multiple Facets. BIOLOGY 2018; 7:biology7020034. [PMID: 29895729 PMCID: PMC6022934 DOI: 10.3390/biology7020034] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 05/25/2018] [Accepted: 06/07/2018] [Indexed: 11/16/2022]
Abstract
Carbamyl phosphate (CP) is well-known as an essential intermediate of pyrimidine and arginine/urea biosynthesis. Chemically, CP can be easily synthesized from dihydrogen phosphate and cyanate. Enzymatically, CP can be synthesized using three different classes of enzymes: (1) ATP-grasp fold protein based carbamyl phosphate synthetase (CPS); (2) Amino-acid kinase fold carbamate kinase (CK)-like CPS (anabolic CK or aCK); and (3) Catabolic transcarbamylase. The first class of CPS can be further divided into three different types of CPS as CPS I, CPS II, and CPS III depending on the usage of ammonium or glutamine as its nitrogen source, and whether N-acetyl-glutamate is its essential co-factor. CP can donate its carbamyl group to the amino nitrogen of many important molecules including the most well-known ornithine and aspartate in the arginine/urea and pyrimidine biosynthetic pathways. CP can also donate its carbamyl group to the hydroxyl oxygen of a variety of molecules, particularly in many antibiotic biosynthetic pathways. Transfer of the carbamyl group to the nitrogen group is catalyzed by the anabolic transcarbamylase using a direct attack mechanism, while transfer of the carbamyl group to the oxygen group is catalyzed by a different class of enzymes, CmcH/NodU CTase, using a different mechanism involving a three-step reaction, decomposition of CP to carbamate and phosphate, transfer of the carbamyl group from carbamate to ATP to form carbamyladenylate and pyrophosphate, and transfer of the carbamyl group from carbamyladenylate to the oxygen group of the substrate. CP is also involved in transferring its phosphate group to ADP to generate ATP in the fermentation of many microorganisms. The reaction is catalyzed by carbamate kinase, which may be termed as catabolic CK (cCK) in order to distinguish it from CP generating CK. CP is a thermally labile molecule, easily decomposed into phosphate and cyanate, or phosphate and carbamate depending on the pH of the solution, or the presence of enzyme. Biological systems have developed several mechanisms including channeling between enzymes, increased affinity of CP to enzymes, and keeping CP in a specific conformation to protect CP from decomposition. CP is highly important for our health as both a lack of, or decreased, CP production and CP accumulation results in many disease conditions.
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Affiliation(s)
- Dashuang Shi
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA.
- Department of Genomics and Precision Medicine, The George Washington University, Washington, DC 20010, USA.
| | - Ljubica Caldovic
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA.
- Department of Genomics and Precision Medicine, The George Washington University, Washington, DC 20010, USA.
| | - Mendel Tuchman
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA.
- Department of Genomics and Precision Medicine, The George Washington University, Washington, DC 20010, USA.
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16
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Wang Y, Chang L, Zhai J, Wu Q, Wang D, Wang Y. Generation of carbamoyl phosphate synthetase 1 reporter cell lines for the assessment of ammonia metabolism. J Cell Mol Med 2017; 21:3214-3223. [PMID: 28557353 PMCID: PMC5706564 DOI: 10.1111/jcmm.13225] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 04/09/2017] [Indexed: 01/25/2023] Open
Abstract
Both primary hepatocytes and stem cells-derived hepatocyte-like cells (HLCs) are major sources for bioartificial liver (BAL). Maintenance of hepatocellular functions and induction of functional maturity of HLCs are critical for BAL's support effect. It remains difficult to assess and improve detoxification functions inherent to hepatocytes, including ammonia clearance. Here, we aim to assess ammonia metabolism and identify ammonia detoxification enhancer by developing an imaging strategy. In hepatoma cell line HepG2, and immortalized hepatic cell line LO2, carbamoyl phosphate synthetase 1 (CPS1) gene, the first enzyme of ammonia-eliminating urea cycle, was labelled with fluorescence protein via CRISPR/Cas9 system. With the reporter-based screening approach, cellular detoxification enhancers were selected among a collection of 182 small molecules. In both CPS1 reporter cell lines, the fluorescence intensity is positively correlated with cellular CPS1 mRNA expression, ammonia elimination and secreted urea, and reflected ammonia detoxification in a dose-dependent manner. Surprisingly, high-level CPS1 reporter clones also reserved many other critical hepatocellular functions, for example albumin secretion and cytochrome 450 metabolic functions. Sodium phenylbutyrate and resveratrol were identified to enhance metabolism-related gene expression and liver-enriched transcription factors C/EBPα, HNF4α. In conclusion, the CPS1-reporter system provides an economic and effective platform for assessment of cellular metabolic function and high-throughput identification of chemical compounds that improve detoxification activities in hepatic lineage cells.
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Affiliation(s)
- Yi Wang
- Stem Cell and Tissue Engineering LabBeijing Institute of Transfusion MedicineBeijingChina
| | - Le Chang
- Stem Cell and Tissue Engineering LabBeijing Institute of Transfusion MedicineBeijingChina
| | - Jiahui Zhai
- Stem Cell and Tissue Engineering LabBeijing Institute of Transfusion MedicineBeijingChina
| | - Qiao Wu
- Capital Medical University Youan hospitalBeijingChina
| | - Donggen Wang
- Stem Cell and Tissue Engineering LabBeijing Institute of Transfusion MedicineBeijingChina
| | - Yunfang Wang
- Stem Cell and Tissue Engineering LabBeijing Institute of Transfusion MedicineBeijingChina
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17
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Massafra V, van Mil SWC. Farnesoid X receptor: A "homeostat" for hepatic nutrient metabolism. Biochim Biophys Acta Mol Basis Dis 2017; 1864:45-59. [PMID: 28986309 DOI: 10.1016/j.bbadis.2017.10.003] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 09/27/2017] [Accepted: 10/02/2017] [Indexed: 02/06/2023]
Abstract
The Farnesoid X receptor (FXR) is a nuclear receptor activated by bile acids (BAs). BAs are amphipathic molecules that serve as fat solubilizers in the intestine under postprandial conditions. In the post-absorptive state, BAs bind FXR in the hepatocytes, which in turn provides feedback signals on BA synthesis and transport and regulates lipid, glucose and amino acid metabolism. Therefore, FXR acts as a homeostat of all three classes of nutrients, fats, sugars and proteins. Here we re-analyze the function of FXR in the perspective of nutritional metabolism, and discuss the role of FXR in liver energy homeostasis in postprandial, post-absorptive and fasting/starvation states. FXR, by regulating nutritional metabolism, represses autophagy in conditions of nutrient abundance, and controls the metabolic needs of proliferative cells. In addition, FXR regulates inflammation via direct effects and via its impact on nutrient metabolism. These functions indicate that FXR is an attractive therapeutic target for liver diseases.
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Affiliation(s)
- Vittoria Massafra
- Center for Molecular Medicine, UMC Utrecht, Utrecht, The Netherlands
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18
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Wu C, Chen CH, Chen HC, Liang HJ, Chen ST, Lin WY, Wu KY, Chiang SY, Lin CY. Nuclear magnetic resonance- and mass spectrometry-based metabolomics to study maleic acid toxicity from repeated dose exposure in rats. J Appl Toxicol 2017; 37:1493-1506. [PMID: 28691739 DOI: 10.1002/jat.3500] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 05/16/2017] [Accepted: 05/21/2017] [Indexed: 01/11/2023]
Abstract
Maleic acid (MA), a chemical intermediate used in many consumer and industrial products, was intentionally adulterated in a variety of starch-based foods and instigated food safety incidents in Asia. We aim to elucidate possible mechanisms of MA toxicity after repeated exposure by (1) determining the changes of metabolic profile using 1 H nuclear magnetic resonance spectroscopy and multivariate analysis, and (2) investigating the occurrence of oxidative stress using liquid chromatography tandem mass spectrometry by using Sprague-Dawley rat urine samples. Adult male rats were subjected to a 28 day subchronic study (0, 6, 20 and 60 mg kg-1 ) via oral gavage. Urine was collected twice a day on days 0, 7, 14, 21 and 28; organs underwent histopathological examination. Changes in body weight and relative kidney weights in medium- and high-dose groups were significantly different compared to controls. Morphological alterations were evident in the kidneys and liver. Metabolomic results demonstrated that MA exposure increases the urinary concentrations of 8-hydroxy-2'-deoxyguanosine, 8-nitroguanine and 8-iso-prostaglandin F2α ; levels of acetoacetate, hippurate, alanine and acetate demonstrated time- and dose-dependent variations in the treatment groups. Findings suggest that MA consumption escalates oxidative damage, membrane lipid destruction and disrupt energy metabolism. These aforementioned changes in biomarkers and endogenous metabolites elucidate and assist in characterizing the possible mechanisms by which MA induces nephro- and hepatotoxicity.
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Affiliation(s)
- Charlene Wu
- Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, No. 17, ShiuJou Rd., Taipei, 10055, Taiwan
| | - Chi-Hung Chen
- Institute of Environmental Health, College of Public Health, National Taiwan University, No. 17, ShiuJou Rd., Taipei, 10055, Taiwan
| | - Hsin-Chang Chen
- Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, No. 17, ShiuJou Rd., Taipei, 10055, Taiwan
| | - Hao-Jan Liang
- Institute of Environmental Health, College of Public Health, National Taiwan University, No. 17, ShiuJou Rd., Taipei, 10055, Taiwan
| | - Shu-Ting Chen
- National Environmental Health Research Center, National Health Research Institutes, No. 35, Keyan Rd., Zhunan, Miaoli County, 35053, Taiwan
| | - Wan-Yu Lin
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, No. 17, ShiuJou Rd., Taipei, 10055, Taiwan
| | - Kuen-Yuh Wu
- Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, No. 17, ShiuJou Rd., Taipei, 10055, Taiwan
| | - Su-Yin Chiang
- School of Chinese Medicine, China Medical University, Taichung, 404, Taiwan
| | - Ching-Yu Lin
- Institute of Environmental Health, College of Public Health, National Taiwan University, No. 17, ShiuJou Rd., Taipei, 10055, Taiwan
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Abstract
RATIONALE The carbamoyl phosphate synthetase I deficiency (CPS1D) was rare and hard to diagnose due to its atypical symptoms. Brain magnetic resonance imaging (MRI) was typically unavailable in other reports because most patients died before diagnosis was confirmed. Furthermore, it was found a new mutation that had not been described previously. PATIENT CONCERNS This is a case of neonatal-onset CPS1D with nonspecific clinical manifestations and deteriorating rapidly. Poor feeding, low activity, and tachypnoea were observed, with rapid progression on day 2 after birth. Severe systematic infection was considered first. However, blood culture and cerebrospinal fluid examination were negative. Symptoms were relief temporarily. Then seizure and tachypnoea reappeared as intravenous amino acids were provided. Further examination indicated severe hyperammonemia (serum ammonia level >500mmol/L). Brain MRI showed diffused white matter lesions. DIAGNOSES Genetic analysis revealed 2 heterozygous mutations in the CPS1 gene: c.2407C>G (p.803, R>G) in exon 20 and C.323G>A (p.108, G>E) in exon 4. The diagnosis of CSP1D was confirmed. INTERVENTIONS Fasting, the withdrawal of amino acids and plans to treat hyperammonemia were immediately implemented. OUTCOMES The parents decided to discontinue medical care. LESSONS Many CPS1D patients died before the diagnoses are confirmed due to its sudden onset, rapid deterioration, atypical symptoms, and low morbidity. Once hyperammonemia is confirmed, blood and urea amino acid analysis in combination with genetic examinations should be performed as early as possible, this approach would help establish diagnoses at an early stage and thus contribute to reducing mortality and improving prognosis.
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Affiliation(s)
- Xiaoyan Yang
- Department of Pediatrics, West China Second University Hospital
- Key Laboratory of Obstetric & Gynaecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, Sichuan, China
| | - Jing Shi
- Department of Pediatrics, West China Second University Hospital
- Key Laboratory of Obstetric & Gynaecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, Sichuan, China
| | - Haihong Lei
- Department of Pediatrics, West China Second University Hospital
- Key Laboratory of Obstetric & Gynaecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, Sichuan, China
| | - Bin Xia
- Department of Pediatrics, West China Second University Hospital
- Key Laboratory of Obstetric & Gynaecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, Sichuan, China
| | - Dezhi Mu
- Department of Pediatrics, West China Second University Hospital
- Key Laboratory of Obstetric & Gynaecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, Sichuan, China
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20
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Amino acid homeostasis and signalling in mammalian cells and organisms. Biochem J 2017; 474:1935-1963. [PMID: 28546457 PMCID: PMC5444488 DOI: 10.1042/bcj20160822] [Citation(s) in RCA: 306] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/08/2017] [Accepted: 03/10/2017] [Indexed: 12/19/2022]
Abstract
Cells have a constant turnover of proteins that recycle most amino acids over time. Net loss is mainly due to amino acid oxidation. Homeostasis is achieved through exchange of essential amino acids with non-essential amino acids and the transfer of amino groups from oxidised amino acids to amino acid biosynthesis. This homeostatic condition is maintained through an active mTORC1 complex. Under amino acid depletion, mTORC1 is inactivated. This increases the breakdown of cellular proteins through autophagy and reduces protein biosynthesis. The general control non-derepressable 2/ATF4 pathway may be activated in addition, resulting in transcription of genes involved in amino acid transport and biosynthesis of non-essential amino acids. Metabolism is autoregulated to minimise oxidation of amino acids. Systemic amino acid levels are also tightly regulated. Food intake briefly increases plasma amino acid levels, which stimulates insulin release and mTOR-dependent protein synthesis in muscle. Excess amino acids are oxidised, resulting in increased urea production. Short-term fasting does not result in depletion of plasma amino acids due to reduced protein synthesis and the onset of autophagy. Owing to the fact that half of all amino acids are essential, reduction in protein synthesis and amino acid oxidation are the only two measures to reduce amino acid demand. Long-term malnutrition causes depletion of plasma amino acids. The CNS appears to generate a protein-specific response upon amino acid depletion, resulting in avoidance of an inadequate diet. High protein levels, in contrast, contribute together with other nutrients to a reduction in food intake.
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Chen Z, Tang N, Wang X, Chen Y. The activity of the carbamoyl phosphate synthase 1 promoter in human liver-derived cells is dependent on hepatocyte nuclear factor 3-beta. J Cell Mol Med 2017; 21:2036-2045. [PMID: 28272778 PMCID: PMC5571533 DOI: 10.1111/jcmm.13123] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 01/13/2017] [Indexed: 01/15/2023] Open
Abstract
Carbamoyl phosphate synthase 1 (CPS1) is the rate‐limiting enzyme in the first step of the urea cycle and an indispensable enzyme in the metabolism of human liver. However, CPS1 epigenetic regulation involves promoter analysis and the role of liver‐enriched transcription factors (LETFs), which is not fully elucidated. In this work, the promoter region of hCPS1 gene was cloned, and its activity was investigated. An LETF, hepatocyte nuclear factor 3‐beta (HNF3β), was found to promote the transcriptional expression of CPS1 in liver‐derived cell lines. In addition, dual‐luciferase reporter assay shows that the essential binding sites of the HNF3β may exist in the oligonucleotide −70 nt to +73 nt. Two putative binding sites are available for HNF3β. Mutation analysis results show that the binding site 2 of HNF3β was effective, and the transcriptional activity of CPS1 promoter significantly decreased after mutation. Electrophoretic mobile shift assay (EMSA) and ChIP assay confirmed that HNF3β can interact with the binding site in the CPS1 promoter region of −70 nt to +73 nt promoter region in vivo and in vitro to regulate the transcription of CPS1. Moreover, HNF3β overexpression enhanced the transcription of CPS1 and consequently improved the mRNA and protein levels of CPS1, whereas the knockdown of HNF3β showed the opposite effects. Finally, urea production in cells was measured, and ammonia detoxification improved significantly in cells after transfection with HNF3β. HNF3β plays a vital role in regulation of CPS1 gene and could promote the metabolism of ammonia by regulating CPS1 expression.
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Affiliation(s)
- Zhanfei Chen
- Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, Fuzhou, China
| | - Nanhong Tang
- Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, Fuzhou, China.,Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Research Center for Molecular Medicine, Fujian Medical University, Fuzhou, China
| | - Xiaoqian Wang
- Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, Fuzhou, China
| | - Yanling Chen
- Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, Fuzhou, China.,Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Research Center for Molecular Medicine, Fujian Medical University, Fuzhou, China
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22
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Shi D, Zhao G, Ah Mew N, Tuchman M. Precision medicine in rare disease: Mechanisms of disparate effects of N-carbamyl-l-glutamate on mutant CPS1 enzymes. Mol Genet Metab 2017; 120:198-206. [PMID: 28007335 PMCID: PMC5346444 DOI: 10.1016/j.ymgme.2016.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/05/2016] [Accepted: 12/05/2016] [Indexed: 02/07/2023]
Abstract
This study documents the disparate therapeutic effect of N-carbamyl-l-glutamate (NCG) in the activation of two different disease-causing mutants of carbamyl phosphate synthetase 1 (CPS1). We investigated the effects of NCG on purified recombinant wild-type (WT) mouse CPS1 and its human corresponding E1034G (increased ureagenesis on NCG) and M792I (decreased ureagenesis on NCG) mutants. NCG activates WT CPS1 sub-optimally compared to NAG. Similar to NAG, NCG, in combination with MgATP, stabilizes the enzyme, but competes with NAG binding to the enzyme. NCG supplementation activates available E1034G mutant CPS1 molecules not bound to NAG enhancing ureagenesis. Conversely, NCG competes with NAG binding to the scarce M792I mutant enzyme further decreasing residual ureagenesis. These results correlate with the respective patient's response to NCG. Particular caution should be taken in the administration of NCG to patients with hyperammonemia before their molecular bases of their urea cycle disorders is known.
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Affiliation(s)
- Dashuang Shi
- Center for Genetic Medicine Research, Department of Integrative Systems Biology, Children's Research Institute, Children's National Health System, The George Washington University, Washington, DC 20010, USA.
| | - Gengxiang Zhao
- Center for Genetic Medicine Research, Department of Integrative Systems Biology, Children's Research Institute, Children's National Health System, The George Washington University, Washington, DC 20010, USA
| | - Nicholas Ah Mew
- Center for Genetic Medicine Research, Department of Integrative Systems Biology, Children's Research Institute, Children's National Health System, The George Washington University, Washington, DC 20010, USA
| | - Mendel Tuchman
- Center for Genetic Medicine Research, Department of Integrative Systems Biology, Children's Research Institute, Children's National Health System, The George Washington University, Washington, DC 20010, USA
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23
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Diez-Fernandez C, Häberle J. Targeting CPS1 in the treatment of Carbamoyl phosphate synthetase 1 (CPS1) deficiency, a urea cycle disorder. Expert Opin Ther Targets 2017; 21:391-399. [PMID: 28281899 DOI: 10.1080/14728222.2017.1294685] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Carbamoyl phosphate synthetase 1 (CPS1) deficiency (CPS1D) is a rare autosomal recessive urea cycle disorder (UCD), which can lead to life-threatening hyperammonemia. Unless promptly treated, it can result in encephalopathy, coma and death, or intellectual disability in surviving patients. Over recent decades, therapies for CPS1D have barely improved leaving the management of these patients largely unchanged. Additionally, in many cases, current management (protein-restriction and supplementation with citrulline and/or arginine and ammonia scavengers) is insufficient for achieving metabolic stability, highlighting the importance of developing alternative therapeutic approaches. Areas covered: After describing UCDs and CPS1D, we give an overview of the structure- function of CPS1. We then describe current management and potential novel treatments including N-carbamoyl-L-glutamate (NCG), pharmacological chaperones, and gene therapy to treat hyperammonemia. Expert opinion: Probably, the first novel CPS1D therapies to reach the clinics will be the already commercial substance NCG, which is the standard treatment for N-acetylglutamate synthase deficiency and has been proven to rescue specific CPS1D mutations. Pharmacological chaperones and gene therapy are under development too, but these two technologies still have key challenges to be overcome. In addition, current experimental therapies will hopefully add further treatment options.
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Affiliation(s)
- Carmen Diez-Fernandez
- a Division of Metabolism , University Children's Hospital Zurich and Children's Research Center , Zurich , Switzerland
| | - Johannes Häberle
- a Division of Metabolism , University Children's Hospital Zurich and Children's Research Center , Zurich , Switzerland
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24
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Chapel-Crespo CC, Diaz GA, Oishi K. Efficacy of N-carbamoyl-L-glutamic acid for the treatment of inherited metabolic disorders. Expert Rev Endocrinol Metab 2016; 11:467-473. [PMID: 30034506 PMCID: PMC6054484 DOI: 10.1080/17446651.2016.1239526] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
INTRODUCTION N-carbamoyl-L-glutamic acid (NCG) is a synthetic analogue of N-acetyl glutamate (NAG) that works effectively as a cofactor for carbamoyl phosphate synthase 1 and enhances ureagenesis by activating the urea cycle. NCG (brand name, Carbaglu) was recently approved by the United States Food and Drug Administration (US FDA) for the management of NAGS deficiency and by the European Medicines Agency (EMA) for the treatment of NAGS deficiency as well as for the treatment of hyperammonenia in propionic, methylmalonic and isovaleric acidemias in Europe. AREAS COVERED The history, mechanism of action, and efficacy of this new drug are described. Moreover, clinical utility of NCG in a variety of inborn errors of metabolism with secondary NAGS deficiency is discussed. EXPERT COMMENTARY NCG has favorable pharmacological features including better bioavailability compared to NAG. The clinical use of NCG has proven to be so effective as to make dietary protein restriction unnecessary for patients with NAGS deficiency. It has been also demonstrated to be effective for hyperammonemia secondary to other types of inborn errors of metabolism. NCG may have additional therapeutic potential in conditions such as hepatic hyperammonemic encephalopathy secondary to chemotherapies or other liver pathology.
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Affiliation(s)
- Cristel C Chapel-Crespo
- Department of Genetics and Genomic Sciences, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - George A Diaz
- Department of Genetics and Genomic Sciences, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Kimihiko Oishi
- Department of Genetics and Genomic Sciences, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Structure of human carbamoyl phosphate synthetase: deciphering the on/off switch of human ureagenesis. Sci Rep 2015; 5:16950. [PMID: 26592762 PMCID: PMC4655335 DOI: 10.1038/srep16950] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 10/22/2015] [Indexed: 01/07/2023] Open
Abstract
Human carbamoyl phosphate synthetase (CPS1), a 1500-residue multidomain enzyme, catalyzes the first step of ammonia detoxification to urea requiring N-acetyl-L-glutamate (NAG) as essential activator to prevent ammonia/amino acids depletion. Here we present the crystal structures of CPS1 in the absence and in the presence of NAG, clarifying the on/off-switching of the urea cycle by NAG. By binding at the C-terminal domain of CPS1, NAG triggers long-range conformational changes affecting the two distant phosphorylation domains. These changes, concerted with the binding of nucleotides, result in a dramatic remodeling that stabilizes the catalytically competent conformation and the building of the ~35 Å-long tunnel that allows migration of the carbamate intermediate from its site of formation to the second phosphorylation site, where carbamoyl phosphate is produced. These structures allow rationalizing the effects of mutations found in patients with CPS1 deficiency (presenting hyperammonemia, mental retardation and even death), as exemplified here for some mutations.
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