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Ueda S, Hirata T, Sakasegawa SI. Hypoxanthine-guanine phosphoribosyltransferase is activated via positive cooperativity between guanine and IMP. FEBS Lett 2022; 596:1072-1080. [PMID: 35114018 DOI: 10.1002/1873-3468.14306] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/16/2022] [Accepted: 01/27/2022] [Indexed: 12/31/2022]
Abstract
Hypoxanthine-guanine phosphoribosyltransferase (HGPRT) is a key enzyme in the purine salvage pathway. Here, the reverse reaction of HGPRT from the thermophilic bacterium Hungateiclostridium thermocellum was studied in the presence of IMP and pyrophosphate. As for the human enzyme, the bacterial HGPRT was activated by guanine. Furthermore, guanine was found to operate as both an activator and an inhibitor. Intriguingly, within the concentration range of guanine where it functions as the activator, the Km value for IMP was not influenced by guanine. Consequently, guanine was found to noncompetitively activate the reverse reaction toward IMP. Here, we propose a reaction scheme that explains the activation mechanism in which the enzyme forms a chimeric oligomer bound to both IMP and guanine.
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Affiliation(s)
- Shigeru Ueda
- Department of Health and Medical Sciences, Faculty of Risk and Crisis Management, Chiba Institute of Science, Choshi, Japan
| | - Tatsuya Hirata
- R&D Group, Diagnostics Department, Asahi Kasei Pharma Corporation, Izunokuni-shi, Japan
| | - Shin-Ichi Sakasegawa
- R&D Group, Diagnostics Department, Asahi Kasei Pharma Corporation, Izunokuni-shi, Japan
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Sutcliffe DJ, Dinasarapu AR, Visser JE, Hoed JD, Seifar F, Joshi P, Ceballos-Picot I, Sardar T, Hess EJ, Sun YV, Wen Z, Zwick ME, Jinnah HA. Induced pluripotent stem cells from subjects with Lesch-Nyhan disease. Sci Rep 2021; 11:8523. [PMID: 33875724 PMCID: PMC8055678 DOI: 10.1038/s41598-021-87955-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 03/24/2021] [Indexed: 12/18/2022] Open
Abstract
Lesch-Nyhan disease (LND) is an inherited disorder caused by pathogenic variants in the HPRT1 gene, which encodes the purine recycling enzyme hypoxanthine-guanine phosphoribosyltransferase (HGprt). We generated 6 induced pluripotent stem cell (iPSC) lines from 3 individuals with LND, along with 6 control lines from 3 normal individuals. All 12 lines had the characteristics of pluripotent stem cells, as assessed by immunostaining for pluripotency markers, expression of pluripotency genes, and differentiation into the 3 primary germ cell layers. Gene expression profiling with RNAseq demonstrated significant heterogeneity among the lines. Despite this heterogeneity, several anticipated abnormalities were readily detectable across all LND lines, including reduced HPRT1 mRNA. Several unexpected abnormalities were also consistently detectable across the LND lines, including decreases in FAR2P1 and increases in RNF39. Shotgun proteomics also demonstrated several expected abnormalities in the LND lines, such as absence of HGprt protein. The proteomics study also revealed several unexpected abnormalities across the LND lines, including increases in GNAO1 decreases in NSE4A. There was a good but partial correlation between abnormalities revealed by the RNAseq and proteomics methods. Finally, functional studies demonstrated LND lines had no HGprt enzyme activity and resistance to the toxic pro-drug 6-thioguanine. Intracellular purines in the LND lines were normal, but they did not recycle hypoxanthine. These cells provide a novel resource to reveal insights into the relevance of heterogeneity among iPSC lines and applications for modeling LND.
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Affiliation(s)
- Diane J Sutcliffe
- Department of Neurology, Emory University School of Medicine, 101 Woodruff Circle, 6305 Woodruff Memorial Building, Atlanta, GA, 30322, USA
| | - Ashok R Dinasarapu
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Jasper E Visser
- Department of Neurology, Cognition and Behavior, Donders Institute for Brain, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Neurology, Amphia Hospital, Breda, The Netherlands
| | - Joery den Hoed
- Department of Neurology, Emory University School of Medicine, 101 Woodruff Circle, 6305 Woodruff Memorial Building, Atlanta, GA, 30322, USA
| | - Fatemeh Seifar
- Department of Neurology, Emory University School of Medicine, 101 Woodruff Circle, 6305 Woodruff Memorial Building, Atlanta, GA, 30322, USA
- Neurosciences Graduate Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, 30322, USA
| | - Piyush Joshi
- Department of Neurology, Emory University School of Medicine, 101 Woodruff Circle, 6305 Woodruff Memorial Building, Atlanta, GA, 30322, USA
| | - Irene Ceballos-Picot
- Laboratoire de Biochimie Métabolomique Et Protéomique, Hôpital Universitaire Necker, Paris, France
| | - Tejas Sardar
- Department of Neurology, Emory University School of Medicine, 101 Woodruff Circle, 6305 Woodruff Memorial Building, Atlanta, GA, 30322, USA
| | - Ellen J Hess
- Department of Neurology, Emory University School of Medicine, 101 Woodruff Circle, 6305 Woodruff Memorial Building, Atlanta, GA, 30322, USA
- Neurosciences Graduate Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, 30322, USA
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Yan V Sun
- Department of Epidemiology, Emory University Rollins School of Public Health, Atlanta, GA. 30322, USA
| | - Zhexing Wen
- Department of Neurology, Emory University School of Medicine, 101 Woodruff Circle, 6305 Woodruff Memorial Building, Atlanta, GA, 30322, USA
- Department of Psychiatry & Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Michael E Zwick
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - H A Jinnah
- Department of Neurology, Emory University School of Medicine, 101 Woodruff Circle, 6305 Woodruff Memorial Building, Atlanta, GA, 30322, USA.
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, 30322, USA.
- Neurosciences Graduate Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, 30322, USA.
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA.
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Abstract
PURPOSE OF REVIEW Lesch-Nyhan Syndrome (LNS) is a metabolic disorder involving mutations in the HGPRT1 gene that result in hyperuricemia, intellectual disability, a dystonic movement disorder, and compulsive self-injury with self-mutilation. The aim of this review is to summarize recent research that documents the extended behavioral, neurologic, and neurocognitive phenotype in classic LNS, to describe milder variants of HGprt deficiency that do not self-injure and have less severe neurological and cognitive deficits, and to provide an update on treatment for associated psychiatric and behavioral disorders. RECENT FINDINGS Psychiatric management utilizes combined behavioral and pharmacological treatment in conjunction with protective equipment and dental management to avert self-injury. Pharmacological management focuses on stabilization of mood and anxiety management. S-adenosylmethionine (SAMe), a physiological intermediate in methylation and transsulfuration, has shown beneficial effects in carefully selected patients who can tolerate the drug. Deep brain stimulation is shown in several case reports and series to reduce or eliminate self-injury and aggression, and in some cases, modify dystonia. SUMMARY This review highlights progress in our understanding of the behavioral and neurocognitive phenotype of Lesch-Nyhan syndrome (HGprt deficiency) and its variants, describes psychiatric and behavioral management, and discusses prospects for new therapies.
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