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Zendehdel R, Hahad O, Panjali Z. Human epithelial lung cell toxicity assessment of collected graphite particles from an iron casting industry (in vitro study). INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2024; 34:3126-3135. [PMID: 38146704 DOI: 10.1080/09603123.2023.2298248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 12/18/2023] [Indexed: 12/27/2023]
Abstract
Workers in the iron casting industries are exposed to various chemicals, especially graphite in furnace process. This study aims to investigate the toxic effects of graphite particles on human lung cells. Particle characteristics were confirmed by electron microscope and light scattering. Cell viability and oxidative stress markers were measured. The expression of oxidative repair genes, namely OGG1, MTH1, and ITPA, was evaluated. The average particle size was determined to be 172.1 ± 11.96 nm. The median inhibition concentration (IC50) of graphite particles was 46.75 µg/mL. Notably, 25 and 50 µg/mL concentrations resulted in significant GSH depletion and MDA production. The high concentration of graphite particles (200 µg/mL) led to OGG1 suppression and increased MTH1 expression. Based on these findings, graphite exposure may induce toxicity in human lung cells by increasing oxidative stress. Further research is necessary to fully understand the mechanisms underlying graphite toxicity.
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Affiliation(s)
- Rezvan Zendehdel
- Department of Occupational Health and Safety, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Omar Hahad
- Department of Cardiology, Cardiology I, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
- German Center for Cardiovascular Research (DZHK), partner site Rhine-Main, Mainz, Germany
| | - Zahra Panjali
- Department of Occupational Health and Safety, Faculty of Health Sciences, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
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2
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Yang TY, Small AM, Dufresne L, Peloso GM, Natarajan P, Engert JC, Thanassoulis G. Plasma Proteomic Biomarkers of Aortic Stenosis: A Mendelian Randomization Study. J Am Coll Cardiol 2024; 84:592-594. [PMID: 39084832 DOI: 10.1016/j.jacc.2024.05.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 04/03/2024] [Accepted: 05/10/2024] [Indexed: 08/02/2024]
Affiliation(s)
- Ta-Yu Yang
- McGill University Health Centre and Research Institute, Montréal, Québec, Canada; McGill University, Montréal, Québec, Canada; Kyoto-McGill International Collaborative School in Genomic Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Aeron M Small
- Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA; Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Line Dufresne
- McGill University Health Centre and Research Institute, Montréal, Québec, Canada
| | - Gina M Peloso
- Boston University School of Public Health, Boston, Massachusetts, USA
| | - Pradeep Natarajan
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA; Massachusetts General Hospital, Boston, Massachusetts, USA; Harvard Medical School, Boston, Massachusetts, USA
| | - James C Engert
- McGill University Health Centre and Research Institute, Montréal, Québec, Canada; McGill University, Montréal, Québec, Canada
| | - George Thanassoulis
- McGill University Health Centre and Research Institute, Montréal, Québec, Canada; McGill University, Montréal, Québec, Canada.
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3
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Burgis NE, VanWormer K, Robbins D, Smith J. An ITPA Enzyme with Improved Substrate Selectivity. Protein J 2024; 43:62-71. [PMID: 38066288 PMCID: PMC10901923 DOI: 10.1007/s10930-023-10162-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2023] [Indexed: 02/29/2024]
Abstract
Recent clinical data have identified infant patients with lethal ITPA deficiencies. ITPA is known to modulate ITP concentrations in cells and has a critical function in neural development which is not understood. Polymorphism of the ITPA gene affects outcomes for both ribavirin and thiopurine based therapies and nearly one third of the human population is thought to harbor ITPA polymorphism. In a previous site-directed mutagenesis alanine screen of the ITPA substrate selectivity pocket, we identified the ITPA mutant, E22A, as a gain-of function mutant with enhanced ITP hydrolysis activity. Here we report a rational enzyme engineering experiment to investigate the biochemical properties of position 22 ITPA mutants and find that the E22D ITPA has two- and four-fold improved substrate selectivity for ITP over the canonical purine triphosphates ATP and GTP, respectively, while maintaining biological activity. The novel E22D ITPA should be considered as a platform for further development of ITPA therapies.
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Affiliation(s)
- Nicholas E Burgis
- Department of Chemistry, Biochemistry & Physics, Eastern Washington University, Cheney, WA, 99004, USA.
| | - Kandise VanWormer
- Department of Chemistry, Biochemistry & Physics, Eastern Washington University, Cheney, WA, 99004, USA
| | - Devin Robbins
- Department of Chemistry, Biochemistry & Physics, Eastern Washington University, Cheney, WA, 99004, USA
| | - Jonathan Smith
- Department of Chemistry, Biochemistry & Physics, Eastern Washington University, Cheney, WA, 99004, USA
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4
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Schroader JH, Handley MT, Reddy K. Inosine triphosphate pyrophosphatase: A guardian of the cellular nucleotide pool and potential mediator of RNA function. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1790. [PMID: 37092460 DOI: 10.1002/wrna.1790] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/10/2023] [Accepted: 03/20/2023] [Indexed: 04/25/2023]
Abstract
Inosine triphosphate pyrophosphatase (ITPase), encoded by the ITPA gene in humans, is an important enzyme that preserves the integrity of cellular nucleotide pools by hydrolyzing the noncanonical purine nucleotides (deoxy)inosine and (deoxy)xanthosine triphosphate into monophosphates and pyrophosphate. Variants in the ITPA gene can cause partial or complete ITPase deficiency. Partial ITPase deficiency is benign but clinically relevant as it is linked to altered drug responses. Complete ITPase deficiency causes a severe multisystem disorder characterized by seizures and encephalopathy that is frequently associated with fatal infantile dilated cardiomyopathy. In the absence of ITPase activity, its substrate noncanonical nucleotides have the potential to accumulate and become aberrantly incorporated into DNA and RNA. Hence, the pathophysiology of ITPase deficiency could arise from metabolic imbalance, altered DNA or RNA regulation, or from a combination of these factors. Here, we review the known functions of ITPase and highlight recent work aimed at determining the molecular basis for ITPA-associated pathogenesis which provides evidence for RNA dysfunction. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.
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Affiliation(s)
- Jacob H Schroader
- The RNA Institute, University at Albany, State University of New York, Albany, New York, USA
- Department of Biological Sciences, University at Albany, State University of New York, Albany, New York, USA
| | - Mark T Handley
- Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Kaalak Reddy
- The RNA Institute, University at Albany, State University of New York, Albany, New York, USA
- Department of Biological Sciences, University at Albany, State University of New York, Albany, New York, USA
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5
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Heidari M, Khalili M, Balouchi F, Roozbeh J, Shamsaefar AR, Malek Hosseini SA, Karimi MH. Investigation of the Association Between ITPA Gene 94C>A Sequence Variant and Kidney Transplant Rejection in Iranian Kidney Transplant Recipients. EXP CLIN TRANSPLANT 2023; 21:652-656. [PMID: 37698399 DOI: 10.6002/ect.2023.0066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
OBJECTIVES Thiopurine prodrugs are commonly used in kidney transplant recipients. Inosine triphosphate pyrophosphatase is an enzyme encoded by the ITPA gene. Alteration of ITPA gene is one of the pharmacogenetic sequence variants possibly involved in thiopurine metabolism. The ITPA 94C>A sequence variant (C-to-A substitution at nucleotide 94) is associated with an increased risk of adverse drug reactions in patients treated with the thiopurine drug. The aim of the present study was to investigate the effect of the ITPA 94C>A gene sequence variant in kidney transplant recipients. MATERIALS AND METHODS The genotyping of the ITPA rs1127354 variant was performed by the polymerase chain reaction restriction fragment length polymorphism method in 140 kidney transplant recipients and in 100 control participants. Data were analyzed with SPSS statistical software. RESULTS The results revealed a significant difference between control and nonrejection groups regarding the rs1127354 genotype and allele frequency. No significant difference was found between the rejection and nonrejection groups regarding the rs1127354 genotype and allele frequency. Also, a significant association was observed between the ageofthe control group and age of the rejection group. No significant differences between sex and underlying disease in patients with or without rejection were observed. CONCLUSIONS We observed no significant differences between rejection and nonrejection transplant. Further studies are recommended, in a larger population and with different ethnicities.
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Affiliation(s)
- Mozhdeh Heidari
- >From the Transplant Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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6
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Burgis NE, April C, VanWormer K. Arginine-178 is an essential residue for ITPA function. Arch Biochem Biophys 2023; 744:109700. [PMID: 37506994 PMCID: PMC10530447 DOI: 10.1016/j.abb.2023.109700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/18/2023] [Accepted: 07/22/2023] [Indexed: 07/30/2023]
Abstract
The inosine triphosphate pyrophosphatase (ITPA) enzyme plays a critical cellular role by removing noncanonical nucleoside triphosphates from nucleotide pools. One of the first pathological ITPA mutants identified is R178C (rs746930990), which causes a fatal infantile encephalopathy, termed developmental and epileptic encephalopathy 35 (DEE 35). The accumulation of noncanonical nucleotides such as inosine triphosphate (ITP), is suspected to affect RNA and/or interfere with normal nucleotide function, leading to development of DEE 35. Molecular dynamics simulations have shown that the very rare R178C mutation does not significantly perturb the overall structure of the protein, but results in a high level of structural flexibility and disrupts active-site hydrogen bond networks, while preliminary biochemical data indicate that ITP hydrolyzing activity is significantly reduced for the R178C mutant. Here we report Michaelis-Menten enzyme kinetics data for the R178C ITPA mutant and three other position 178 ITPA mutants. These data confirm that position 178 is essential for ITPA activity and even conservative mutation at this site (R178K) results in significantly reduced enzyme activity. Our data support that disruption of the active-site hydrogen bond network is a major cause of diminished ITP hydrolyzing activity for the R178C mutation. These results suggest an avenue for developing therapies to address DEE 35.
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Affiliation(s)
- Nicholas E Burgis
- Department of Chemistry, Biochemistry & Physics, Eastern Washington University, Cheney, WA, 99004, USA.
| | - Caitlin April
- Department of Chemistry, Biochemistry & Physics, Eastern Washington University, Cheney, WA, 99004, USA
| | - Kandise VanWormer
- Department of Chemistry, Biochemistry & Physics, Eastern Washington University, Cheney, WA, 99004, USA
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7
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Palmer DS, Zhou W, Abbott L, Wigdor EM, Baya N, Churchhouse C, Seed C, Poterba T, King D, Kanai M, Bloemendal A, Neale BM. Analysis of genetic dominance in the UK Biobank. Science 2023; 379:1341-1348. [PMID: 36996212 PMCID: PMC10345642 DOI: 10.1126/science.abn8455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 02/15/2023] [Indexed: 04/01/2023]
Abstract
Classical statistical genetics theory defines dominance as any deviation from a purely additive, or dosage, effect of a genotype on a trait, which is known as the dominance deviation. Dominance is well documented in plant and animal breeding. Outside of rare monogenic traits, however, evidence in humans is limited. We systematically examined common genetic variation across 1060 traits in a large population cohort (UK Biobank, N = 361,194 samples analyzed) for evidence of dominance effects. We then developed a computationally efficient method to rapidly assess the aggregate contribution of dominance deviations to heritability. Lastly, observing that dominance associations are inherently less correlated between sites at a genomic locus than their additive counterparts, we explored whether they may be leveraged to identify causal variants more confidently.
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Affiliation(s)
- Duncan S. Palmer
- Analytical and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Wei Zhou
- Analytical and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Liam Abbott
- Analytical and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Nikolas Baya
- Analytical and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Claire Churchhouse
- Analytical and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Cotton Seed
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Tim Poterba
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Daniel King
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Masahiro Kanai
- Analytical and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Alex Bloemendal
- Analytical and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Benjamin M. Neale
- Analytical and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
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8
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Eltantawy N, El-Zayyadi IAEH, Elberry AA, Salah LM, Abdelrahim MEA, Kassem AB. Association of genetic polymorphism of NUDT15, TPMT and ITPA gene in the toxicity and efficacy of azathioprine-based regimen in Egyptian inflammatory bowel disease patients. BENI-SUEF UNIVERSITY JOURNAL OF BASIC AND APPLIED SCIENCES 2023. [DOI: 10.1186/s43088-023-00340-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Abstract
Background
Inflammatory Bowel disease (IBD) is a chronic progressive condition that prompts generous physical and mental morbidity. Choosing the best kind of management and medication dosage prevents new episodes of high disease activity during therapy because of adverse drug reactions (ADRs). This can lead to cessation or inefficacy of the treatment, or complete non-responsiveness to specific medications. Pharmacogenetics (PGx) is a well-established aspect in IBD. One of the exemplary instances of PGx is thiopurines, which are frequently utilized as IBD therapy. This study aimed to evaluate specific gene polymorphism involved in the toxicity and efficacy of Azathioprine (AZA) use in the management in Egyptian patients and to find the correlation between the polymorphism of Nudix Hydrolase15 (NUDT15) gene (rs116855232), The Thiopurine methyltransferase (TPMT) gene (rs1800460) and Inosine Triphosphatase (ITPA) gene (rs1127354) which are involved in the metabolism of the medications utilized in IBD management.
Methods
This prospective study was performed in 150 patients with IBD. All patients were treated with 2 mg/kg per day AZA (Imuran, GlaxoSmithKline®) for at least 3 months at therapeutic doses to induce remission. Subsequent treatment of AZA. The minimum follow-up period for those who did not experience ADR was one year. Among the studied patients, one hundred twenty-nine patients were treated with combination regimen of steroids (oral prednisone 1 mg/kg/day).
Also, treatment failure was considered among the patients who could not tolerate AZA side effects, or there was no improvement after dose modification.
Results
The most identifiable adverse effect among the studied population was anemia followed by leukopenia and myelosuppression. SNPs genotype TPMT (rs1800460) and ITPA gene (rs1127354) were significantly related to adverse effects among IBD patients receiving Azathioprine treatment. There was a lack of any variants in the NUDT15 genotype among the Egyptian population.
Conclusion
Further research is required in to clarify the relationship between NUDT15 PGx and AZA-ADRs. The effect of NUDT15 PGx on toxicity and ADRs as yet necessitates to be elucidated. Studies with a larger sample size and involving different ethnicities are also necessary.
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Heidari M, Khalili M, Malek Hosseini SA, Geramizadeh B, Shamsaefar AR, Balouchi F, Karimi MH. Investigation of the Association Between the ITPA Gene 94C>A Gene Sequence Variant and Liver Transplant Rejection in Iranian Liver Transplant Recipients. EXP CLIN TRANSPLANT 2022; 20:1094-1098. [PMID: 36718008 DOI: 10.6002/ect.2022.0362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVES Inosine triphosphate pyrophosphatase is an enzyme encoded by the ITPA gene and functions to prevent the incorporation of thiopurine nucleotides into DNA and RNA. Thiopurine drug metabolites such as azathioprine and 6-mercaptopurine have been included in the lists of inosine triphosphate pyrophosphatase substrates. Inosine triphosphatase gene alterations are other pharmacogenetic sequence variants possibly involved in thiopurine metabolism. This study aimed to evaluate the possible association between ITPA 94C>A gene sequence variant (C-to-A substitution at nucleotide 94) in liver transplant recipients. MATERIALS AND METHODS The genotyping of ITPA 94C>A was evaluated by the polymerase chain reaction- restriction fragment length polymorphism method in 200 liver transplant recipients as well as 100 controls. Data were analyzed with SPSS statistical software. RESULTS This study showed statistically significant associations between the CA genotype of the ITPA 94C>A sequence variant and liver transplant in the rejection and nonrejection groups. Moreover, the results reported in this study showed no significant differences between sex, age, and blood group in patients with liver transplant (with or without transplant rejection). CONCLUSIONS Our results indicated that there were statistically significant associations of the CA genotype of ITPA 94C>A sequence variant with liver transplant in the rejection and nonrejection groups. Further studies are recommended.
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Affiliation(s)
- Mozhdeh Heidari
- From the Transplant Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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10
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Schroader JH, Jones LA, Meng R, Shorrock HK, Richardson J, Shaughnessy S, Lin Q, Begley T, Berglund J, Fuchs G, Handley M, Reddy K. Disease-associated inosine misincorporation into RNA hinders translation. Nucleic Acids Res 2022; 50:9306-9318. [PMID: 35979951 PMCID: PMC9458462 DOI: 10.1093/nar/gkac709] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 07/08/2022] [Accepted: 08/06/2022] [Indexed: 12/24/2022] Open
Abstract
Failure to prevent accumulation of the non-canonical nucleotide inosine triphosphate (ITP) by inosine triphosphate pyrophosphatase (ITPase) during nucleotide synthesis results in misincorporation of inosine into RNA and can cause severe and fatal developmental anomalies in humans. While the biochemical activity of ITPase is well understood, the pathogenic basis of ITPase deficiency and the molecular and cellular consequences of ITP misincorporation into RNA remain cryptic. Here, we demonstrate that excess ITP in the nucleotide pool during in vitro transcription results in T7 polymerase-mediated inosine misincorporation in luciferase RNA. In vitro translation of inosine-containing luciferase RNA reduces resulting luciferase activity, which is only partly explained by reduced abundance of the luciferase protein produced. Using Oxford Nanopore Direct RNA sequencing, we reveal inosine misincorporation to be stochastic but biased largely towards misincorporation in place of guanosine, with evidence for misincorporation also in place of cytidine, adenosine and uridine. Inosine misincorporation into RNA is also detected in Itpa-null mouse embryonic heart tissue as an increase in relative variants compared with the wild type using Illumina RNA sequencing. By generating CRISPR/Cas9 rat H9c2 Itpa-null cardiomyoblast cells, we validate a translation defect in cells that accumulate inosine within endogenous RNA. Furthermore, we observe hindered cellular translation of transfected luciferase RNA containing misincorporated inosine in both wild-type and Itpa-null cells. We therefore conclude that inosine misincorporation into RNA perturbs translation, thus providing mechanistic insight linking ITPase deficiency, inosine accumulation and pathogenesis.
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Affiliation(s)
| | | | - Ryan Meng
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Hannah K Shorrock
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Jared I Richardson
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA,Department of Biochemistry and Molecular Biology, Center for NeuroGenetics, University of Florida, Gainesville, FL 32611, USA
| | - Sharon M Shaughnessy
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Qishan Lin
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA,RNA Epitranscriptomics & Proteomics Resource, University at Albany, Albany, NY 12222, USA
| | - Thomas J Begley
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA,Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA,RNA Epitranscriptomics & Proteomics Resource, University at Albany, Albany, NY 12222, USA
| | - J Andrew Berglund
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA,Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA,Department of Biochemistry and Molecular Biology, Center for NeuroGenetics, University of Florida, Gainesville, FL 32611, USA
| | - Gabriele Fuchs
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA,Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Mark T Handley
- Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Kaalak Reddy
- *To whom correspondence should be addressed. Tel: +1 518 442 1464;
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11
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Sharma Y, Saini AG, Kaur R, Bhatia V, Didwal G, Kumar P, Uppala R. Neurodegeneration and Early Infantile Epilepsy Associated with ITPA Variants: A Case Series and Review of Literature. Neuropediatrics 2022; 53:167-175. [PMID: 35098521 DOI: 10.1055/s-0042-1742322] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND Inosine triphosphate pyrophosphohydrolase (ITPase) deficiency associated with mutations in the ITPA gene is a recently characterized purine pathway defect that presents with early infantile epileptic encephalopathy and lethal course. This disorder is rare, and only 12 cases are reported worldwide. METHODS We report two additional cases of ITPA-associated neurodegeneration and two pathogenic compound heterozygous variants. We also reviewed the previously published cases of ITPA-associated encephalopathy. RESULTS Both cases presented with progressive infantile-onset encephalopathy, severe developmental delay, microcephaly, facial dysmorphism, and epilepsy. Together with the presented two cases, 14 cases were available for analysis. The mean age of presentation was 16.7 ± 12.4 months (range 3-48 m). The most common clinical features at presentation were developmental delay, seizures, microcephaly, and hypotonia, seen in all 14 (100%) patients. The mean age of seizure onset was 4.75 months (range 2-14 m). Cardiomyopathy was noted in 42% of patients where it was explicitly evaluated (n = 5/12). Consanguinity was reported in 77% of the cases. The cardinal neuroradiological features are T2-signal abnormalities and diffusion restriction in the long tracts, especially the posterior limb of the internal capsule and the optic radiation. The majority of the patients died before 4 years of age (85.7%). CONCLUSION ITPA-related encephalopathy presents with infantile-onset neurodegeneration, progressive microcephaly, and epilepsy. Progressive brain atrophy and diffusion restriction in the white matter tracts are important radiological clues.
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Affiliation(s)
- Yashu Sharma
- Department of Pediatrics, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Arushi Gahlot Saini
- Department of Pediatrics, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Rajdeep Kaur
- Department of Pediatrics, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Vikas Bhatia
- Department of Pediatrics, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Gunjan Didwal
- Department of Pediatrics, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Pawan Kumar
- Department of Pediatrics, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Revathi Uppala
- Genetics Division, Sandor Specialty Diagnostic Pvt Ltd, Hyderabad, Telangana, India
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12
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Inosine triphosphate pyrophosphatase from Trypanosoma brucei cleanses cytosolic pools from deaminated nucleotides. Sci Rep 2022; 12:6408. [PMID: 35436992 PMCID: PMC9016069 DOI: 10.1038/s41598-022-10149-4] [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: 12/20/2021] [Accepted: 04/04/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractInosine triphosphate pyrophosphatases (ITPases) are ubiquitous house-cleaning enzymes that specifically recognize deaminated purine nucleotides and catalyze their hydrolytic cleavage. In this work, we have characterized the Trypanosoma brucei ITPase ortholog (TbITPA). Recombinant TbITPA efficiently hydrolyzes (deoxy)ITP and XTP nucleotides into their respective monophosphate form. Immunolocalization analysis performed in bloodstream forms suggests that the primary role of TbITPA is the exclusion of deaminated purines from the cytosolic nucleoside triphosphate pools. Even though ITPA-knockout bloodstream parasites are viable, they are more sensitive to inhibition of IMP dehydrogenase with mycophenolic acid, likely due to an expansion of IMP, the ITP precursor. On the other hand, TbITPA can also hydrolyze the activated form of the antiviral ribavirin although in this case, the absence of ITPase activity in the cell confers protection against this nucleoside analog. This unexpected phenotype is dependant on purine availability and can be explained by the fact that ribavirin monophosphate, the reaction product generated by TbITPA, is a potent inhibitor of trypanosomal IMP dehydrogenase and GMP reductase. In summary, the present study constitutes the first report on a protozoan inosine triphosphate pyrophosphatase involved in the removal of harmful deaminated nucleotides from the cytosolic pool.
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13
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Scala M, Wortmann SB, Kaya N, Stellingwerff MD, Pistorio A, Glamuzina E, van Karnebeek CD, Skrypnyk C, Iwanicka‐Pronicka K, Piekutowska‐Abramczuk D, Ciara E, Tort F, Sheidley B, Poduri A, Jayakar P, Jayakar A, Upadia J, Walano N, Haack TB, Prokisch H, Aldhalaan H, Karimiani EG, Yildiz Y, Ceylan AC, Santiago‐Sim T, Dameron A, Yang H, Toosi MB, Ashrafzadeh F, Akhondian J, Imannezhad S, Mirzadeh HS, Maqbool S, Farid A, Al‐Muhaizea MA, Alshwameen MO, Aldowsari L, Alsagob M, Alyousef A, AlMass R, AlHargan A, Alwadei AH, AlRasheed MM, Colak D, Alqudairy H, Khan S, Lines MA, García Cazorla MÁ, Ribes A, Morava E, Bibi F, Haider S, Ferla MP, Taylor JC, Alsaif HS, Firdous A, Hashem M, Shashkin C, Koneev K, Kaiyrzhanov R, Efthymiou S, Genomics QS, Schmitt‐Mechelke T, Ziegler A, Issa MY, Elbendary HM, Striano P, Alkuraya FS, Zaki MS, Gleeson JG, Barakat TS, Bierau J, van der Knaap MS, Maroofian R, Houlden H. Clinico-radiological features, molecular spectrum, and identification of prognostic factors in developmental and epileptic encephalopathy due to inosine triphosphate pyrophosphatase (ITPase) deficiency. Hum Mutat 2022; 43:403-419. [PMID: 34989426 PMCID: PMC9152572 DOI: 10.1002/humu.24326] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 12/20/2021] [Accepted: 12/29/2021] [Indexed: 12/12/2022]
Abstract
Developmental and epileptic encephalopathy 35 (DEE 35) is a severe neurological condition caused by biallelic variants in ITPA, encoding inosine triphosphate pyrophosphatase, an essential enzyme in purine metabolism. We delineate the genotypic and phenotypic spectrum of DEE 35, analyzing possible predictors for adverse clinical outcomes. We investigated a cohort of 28 new patients and reviewed previously described cases, providing a comprehensive characterization of 40 subjects. Exome sequencing was performed to identify underlying ITPA pathogenic variants. Brain MRI (magnetic resonance imaging) scans were systematically analyzed to delineate the neuroradiological spectrum. Survival curves according to the Kaplan-Meier method and log-rank test were used to investigate outcome predictors in different subgroups of patients. We identified 18 distinct ITPA pathogenic variants, including 14 novel variants, and two deletions. All subjects showed profound developmental delay, microcephaly, and refractory epilepsy followed by neurodevelopmental regression. Brain MRI revision revealed a recurrent pattern of delayed myelination and restricted diffusion of early myelinating structures. Congenital microcephaly and cardiac involvement were statistically significant novel clinical predictors of adverse outcomes. We refined the molecular, clinical, and neuroradiological characterization of ITPase deficiency, and identified new clinical predictors which may have a potentially important impact on diagnosis, counseling, and follow-up of affected individuals.
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Affiliation(s)
- Marcello Scala
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child HealthUniversità Degli Studi di GenovaGenoaItaly
- Pediatric Neurology and Muscular Diseases UnitIRCCS Istituto Giannina GasliniGenoaItaly
- UCL Queen Square Institute of NeurologyUniversity College LondonLondonUK
| | - Saskia B. Wortmann
- Amalia Children's HospitalRadboud University NijmegenNijmegenThe Netherlands
- University Children's HospitalParacelsus Medical UniversitySalzburgAustria
| | - Namik Kaya
- Department of GeneticsKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
- Department of Translational Genomics, Center for Genomics MedicineKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
| | - Menno D. Stellingwerff
- Department of Child Neurology, Emma Children's Hospital, Amsterdam Leukodystrophy Center, Amsterdam University Medical CentersVrije Universiteit and Amsterdam NeuroscienceAmsterdamThe Netherlands
| | - Angela Pistorio
- Clinical Epidemiology and Biostatistics UnitIRCCS Istituto Giannina GasliniGenoaItaly
| | - Emma Glamuzina
- Adult and Paediatric National Metabolic ServiceStarship Children's HospitalAucklandNew Zealand
| | - Clara D. van Karnebeek
- Departments of Pediatrics and Clinical GeneticsAcademic Medical CentreAmsterdamThe Netherlands
| | - Cristina Skrypnyk
- Department of Molecular Medicine, Al‐Jawhara Centre for Molecular MedicineArabian Gulf UniversityManamaKingdom of Bahrain
| | - Katarzyna Iwanicka‐Pronicka
- Department of Medical GeneticsThe Children's Memorial Health InstituteWarsawPoland
- Department of Audiology and PhoniatricsThe Children's Memorial Health InstituteWarsawPoland
| | | | - Elżbieta Ciara
- Department of Medical GeneticsThe Children's Memorial Health InstituteWarsawPoland
| | - Frederic Tort
- Secció d'Errors Congènits del Metabolisme‐IBC, Servei de Bioquímica iGenètica MolecularHospital Clínic, IDIBAPS, CIBERERBarcelonaSpain
| | - Beth Sheidley
- Department of NeurologyF.M. Kirby Neurobiology Center, Boston Children's HospitalBostonMassachusettesUSA
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics ProgramBoston Children's HospitalBostonMassachusettesUSA
| | - Annapurna Poduri
- Department of NeurologyF.M. Kirby Neurobiology Center, Boston Children's HospitalBostonMassachusettesUSA
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics ProgramBoston Children's HospitalBostonMassachusettesUSA
- Department of NeurologyHarvard Medical SchoolBostonMassachusettesUSA
| | | | | | - Jariya Upadia
- Tulane University School of MedicineNew OrleansLouisianaUSA
| | | | - Tobias B. Haack
- Institute of Medical Genetics and Applied GenomicsUniversity of TübingenTübingenGermany
| | - Holger Prokisch
- Institute of Human GeneticsTechnische Universität MünchenMunichGermany
- Institute of Human GeneticsHelmholtz Zentrum MünchenNeuherbergGermany
| | - Hesham Aldhalaan
- Department of NeurosciencesKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
| | - Ehsan G. Karimiani
- Department of Medical GeneticsNext Generation Genetic PolyclinicMashhadIran
- Molecular and Clinical Sciences InstituteSt. George's University of London, Cranmer TerraceLondonUK
- Innovative Medical Research CenterIslamic Azad University, Mashhad BranchMashhadIran
| | - Yilmaz Yildiz
- Pediatric Metabolic Diseases ClinicDr. Sami Ulus Training and Research Hospital for Maternity and ChildrenAnkaraTurkey
| | - Ahmet C. Ceylan
- Department of Medical GeneticsAnkara City HospitalAnkaraTurkey
| | | | | | | | - Mehran B. Toosi
- Pediatric Neurology Department, Ghaem HospitalMashhad University of Medical SciencesMashhadIran
| | - Farah Ashrafzadeh
- Department of PediatricsMashhad University of Medical SciencesMashhadIran
| | - Javad Akhondian
- Pediatric Neurology Department, Ghaem HospitalMashhad University of Medical SciencesMashhadIran
| | - Shima Imannezhad
- Department of Pediatric DiseasesMashhad University of Medical SciencesMashhadIran
| | - Hanieh S. Mirzadeh
- Department of Pediatric DiseasesMashhad University of Medical SciencesMashhadIran
| | - Shazia Maqbool
- Development and Behavioral Pediatrics DepartmentInstitute of Child Health and The Children HospitalLahorePakistan
| | - Aisha Farid
- Development and Behavioral Pediatrics DepartmentInstitute of Child Health and The Children HospitalLahorePakistan
| | - Mohamed A. Al‐Muhaizea
- Department of NeurosciencesKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
| | - Meznah O. Alshwameen
- Department of NeurosciencesKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
| | - Lama Aldowsari
- Department of GeneticsKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
| | - Maysoon Alsagob
- Department of GeneticsKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
| | - Ashwaq Alyousef
- Department of GeneticsKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
| | - Rawan AlMass
- Department of GeneticsKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
| | - Aljouhra AlHargan
- Department of GeneticsKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
| | - Ali H. Alwadei
- Neurosciences DepartmentKing Fahad Medical CityRiyadhSaudi Arabia
| | - Maha M. AlRasheed
- Department of Clinical PharmacyKing Saud UniversityRiyadhSaudi Arabia
| | - Dilek Colak
- Department of Biostatistics, Epidemiology and Scientific ComputingKFSHRCRiyadhKingdom of Saudi Arabia
| | - Hanan Alqudairy
- Department of GeneticsKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
| | - Sameena Khan
- Department of NeurosciencesKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
| | - Matthew A. Lines
- Medical Genetics, Department of PediatricsAlberta Children's HospitalCalgaryCanada
| | | | - Antonia Ribes
- Secció d'Errors Congènits del Metabolisme‐IBC, Servei de Bioquímica iGenètica MolecularHospital Clínic, IDIBAPS, CIBERERBarcelonaSpain
| | - Eva Morava
- Department of Clinical Genomics, Laboratory of Medicine and PathologyCenter for Individualized Medicine, Mayo ClinicRochesterMinnesotaUSA
| | - Farah Bibi
- Institute of Biochemistry and BiotechnologyPir Mehar Ali Shah Arid Agriculture UniversityRawalpindiPakistan
| | - Shahzad Haider
- Izzat Ali Shah HospitalLalarukh Wah CanttRawalpindiPakistan
| | - Matteo P. Ferla
- NIHR Oxford BRC Genomic Medicine, Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - Jenny C. Taylor
- NIHR Oxford BRC Genomic Medicine, Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - Hessa S. Alsaif
- Department of Translational Genomics, Center for Genomics MedicineKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
| | - Abdulwahab Firdous
- Department of Translational Genomics, Center for Genomics MedicineKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
| | - Mais Hashem
- Department of Translational Genomics, Center for Genomics MedicineKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
| | - Chingiz Shashkin
- International University of Postgraduate EducationAlmatyKazakhstan
| | - Kairgali Koneev
- Department of Neurology and NeurosurgeryAsfendiyarov Kazakh National Medical UniversityAlmatyKazakhstan
| | - Rauan Kaiyrzhanov
- UCL Queen Square Institute of NeurologyUniversity College LondonLondonUK
| | | | | | | | - Andreas Ziegler
- Zentrum für Kinder und Jugendmedizin Heidelberg, Sektion Neuropädiatrie und StoffwechselmedizinUniversitätsklinikum HeidelbergHeidelbergGermany
| | - Mahmoud Y. Issa
- Clinical Genetics Department, Human Genetics and Genome Research DivisionNational Research CentreCairoEgypt
| | - Hasnaa M. Elbendary
- Clinical Genetics Department, Human Genetics and Genome Research DivisionNational Research CentreCairoEgypt
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child HealthUniversità Degli Studi di GenovaGenoaItaly
- Pediatric Neurology and Muscular Diseases UnitIRCCS Istituto Giannina GasliniGenoaItaly
| | - Fowzan S. Alkuraya
- Department of Translational Genomics, Center for Genomics MedicineKing Faisal Specialist Hospital and Research CentreRiyadhSaudi Arabia
- Department of Anatomy and Cell BiologyAlfaisal UniversityRiyadhSaudi Arabia
| | - Maha S. Zaki
- Clinical Genetics Department, Human Genetics and Genome Research DivisionNational Research CentreCairoEgypt
| | - Joseph G. Gleeson
- Department of Neuroscience, Rady Children's Institute for Genomic Medicine, Howard Hughes Medical InstituteUniversity of CaliforniaSan DiegoCaliforniaUSA
| | - Tahsin Stefan Barakat
- Department of Clinical Genetics, Erasmus MCUniversity Medical CenterRotterdamThe Netherlands
| | - Jorgen Bierau
- Laboratory of Biochemical Genetics, Department of Clinical GeneticsMaastricht University HospitalMaastrichtThe Netherlands
| | - Marjo S. van der Knaap
- Department of Child Neurology, Emma Children's Hospital, Amsterdam Leukodystrophy Center, Amsterdam University Medical CentersVrije Universiteit and Amsterdam NeuroscienceAmsterdamThe Netherlands
- Department of Functional Genomics, Center for Neurogenomics and Cognitive ResearchVU UniversityAmsterdamThe Netherlands
| | - Reza Maroofian
- UCL Queen Square Institute of NeurologyUniversity College LondonLondonUK
| | - Henry Houlden
- UCL Queen Square Institute of NeurologyUniversity College LondonLondonUK
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14
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Zamzami MA. Inosine Triphosphate Pyrophosphatase (ITPase): Functions, Mutations, Polymorphisms and Its Impact on Cancer Therapies. Cells 2022; 11:384. [PMID: 35159194 PMCID: PMC8833965 DOI: 10.3390/cells11030384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/16/2022] Open
Abstract
Inosine triphosphate pyrophosphatase (ITPase) is an enzyme encoded by the ITPA gene and functions to prevent the incorporation of noncanonical purine nucleotides into DNA and RNA. Specifically, the ITPase catalyzed the hydrolysis of (deoxy) nucleoside triphosphates ((d) NTPs) into the corresponding nucleoside monophosphate with the concomitant release of pyrophosphate. Recently, thiopurine drug metabolites such as azathioprine have been included in the lists of ITPase substrates. Interestingly, inosine or xanthosine triphosphate (ITP/XTP) and their deoxy analogs, deoxy inosine or xanthosine triphosphate (dITP/dXTP), are products of important biological reactions such as deamination that take place within the cellular compartments. However, the incorporation of ITP/XTP, dITP/dXTP, or the genetic deficiency or polymorphism of the ITPA gene have been implicated in many human diseases, including infantile epileptic encephalopathy, early onset of tuberculosis, and the responsiveness of patients to cancer therapy. This review provides an up-to-date report on the ITPase enzyme, including information regarding its discovery, analysis, and cellular localization, its implication in human diseases including cancer, and its therapeutic potential, amongst others.
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Affiliation(s)
- Mazin A. Zamzami
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
- Centre of Artificial Intelligence in Precision Medicines, King Abdulaziz University, Jeddah 21589, Saudi Arabia
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15
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Deben DS, Wong DR, van Bodegraven AA. Current status and future perspectives on the use of therapeutic drug monitoring of thiopurine metabolites in patients with inflammatory bowel disease. Expert Opin Drug Metab Toxicol 2022; 17:1433-1444. [PMID: 35023443 DOI: 10.1080/17425255.2021.2029406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Despite new treatment options for inflammatory bowel disease (IBD), conventional thiopurines remain a common treatment option for maintaining remission, particularly in non-Westernized countries. Therapeutic drug monitoring (TDM) is advised in standard care for optimizing therapy strategies to improve effectiveness, reveal nonadherence and reduce toxicity. Still, the rationale of TDM is debated. AREAS COVERED Key insights on TDM of thiopurine metabolites are discussed. The pharmacology of thiopurines is described, emphasizing the interindividual differences in pharmacogenetics, pharmacokinetics and pharmacodynamics. Pharmacological differences between conventional thiopurines and tioguanine are outlined. Finally, several optimization strategies for thiopurine therapy in IBD are discussed. EXPERT OPINION TDM has been a useful, but limited, tool to individualize thiopurine therapy. Pharmacokinetic data on the active thiopurine metabolites, derived from measurements in erythrocytes, associated with clinical response only partially predict effectiveness and toxicity. An additional pharmacodynamic marker, such as Rac1/pSTAT3 expression in leukocytes, may improve applicability of TDM in the future.
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Affiliation(s)
- Debbie S Deben
- Dept. of Clinical Pharmacy, Clinical pharmacology and Toxicology, Zuyderland Medical Centre, Sittard-Geleen/Heerlen, The Netherlands
| | - Dennis R Wong
- Dept. of Clinical Pharmacy, Clinical pharmacology and Toxicology, Zuyderland Medical Centre, Sittard-Geleen/Heerlen, The Netherlands
| | - Adriaan A van Bodegraven
- Dept. of Gastroenterology, Geriatrics, Internal and Intensive Care Medicine (Co-MIK), Zuyderland Medical Centre Sittard-Geleen/Heerlen, The Netherlands.,Dept. of Gastroenterology and Hepatology, Amsterdam, The Netherlands
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16
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Fugger K, Hewitt G, West SC, Boulton SJ. Tackling PARP inhibitor resistance. Trends Cancer 2021; 7:1102-1118. [PMID: 34563478 DOI: 10.1016/j.trecan.2021.08.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/25/2021] [Accepted: 08/27/2021] [Indexed: 12/23/2022]
Abstract
Homologous recombination-deficient (HRD) tumours, including those harbouring mutations in the BRCA genes, are hypersensitive to treatment with inhibitors of poly(ADP-ribose) polymerase (PARPis). Despite high response rates, most HRD cancers ultimately develop resistance to PARPi treatment through reversion mutations or genetic/epigenetic alterations to DNA repair pathways. Counteracting these resistance pathways, thereby increasing the potency of PARPi therapy, represents a potential strategy to improve the treatment of HRD cancers. In this review, we discuss recent insights derived from genetic screens that have identified a number of novel genes that can be targeted to improve PARPi treatment of HRD cancers and may provide a means to overcome PARPi resistance.
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Affiliation(s)
- Kasper Fugger
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Graeme Hewitt
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Stephen C West
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
| | - Simon J Boulton
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Artios Pharma Ltd. B940, Babraham Research Campus, Cambridge, CB22 3FH, UK.
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17
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Chen ZY, Zhu YH, Zhou LY, Shi WQ, Qin Z, Wu B, Yan Y, Pei YW, Chao NN, Zhang R, Wang MY, Su ZH, Lu XJ, He ZY, Xu T. Association Between Genetic Polymorphisms of Metabolic Enzymes and Azathioprine-Induced Myelosuppression in 1,419 Chinese Patients: A Retrospective Study. Front Pharmacol 2021; 12:672769. [PMID: 34084143 PMCID: PMC8167793 DOI: 10.3389/fphar.2021.672769] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/27/2021] [Indexed: 02/05/2023] Open
Abstract
The aim of this study was to investigate the correlation between genetic polymorphisms of azathioprine-metabolizing enzymes and adverse reactions of myelosuppression. To this end, a retrospective analysis was performed on 1,419 Chinese patients involving 40 different diseases and 3 genes: ITPA (94C>A), TPMT*3 (T>C), and NUDT15 (415C>T). Strict inclusion and exclusion criteria were established to collect the relative cases, and the correlation between azathioprine and myelosuppression was evaluated by adverse drug reaction criteria. The mutation rates of the three genes were 29.32, 3.73, and 21.92% and grades I to IV myelosuppression occurred in 54 (9.28%) of the 582 patients who took azathioprine. The highest proportion of myelosuppression was observed in 5 of the 6 (83.33%) patients carrying the NUDT15 (415C>T) TT genotype and 12 of the 102 (11.76%) patients carrying the NUDT15 (415C>T) CT genotype. Only the NUDT15 (415C>T) polymorphism was found to be associated with the adverse effects of azathioprine-induced myelosuppression (odds ratio [OR], 51.818; 95% CI, 5.280–508.556; p = 0.001), which suggested that the NUDT15 (415C>T) polymorphism could be an influencing factor of azathioprine-induced myelosuppression in the Chinese population. Epistatic interactions between ITPA (94C>A) and NUDT15 (415C>T) affect the occurrence of myelosuppression. Thus, it is recommended that the genotype of NUDT15 (415C>T) and ITPA (94C>A) be checked before administration, and azathioprine should be avoided in patients carrying a homozygous NUDT15 (415C>T) mutation. This study is the first to investigate the association between genetic polymorphisms of these three azathioprine-metabolizing enzymes and myelosuppression in a large number of cases with a diverse range of diseases.
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Affiliation(s)
- Zhao-Yang Chen
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yang-Hui Zhu
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Ling-Yan Zhou
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Wei-Qiao Shi
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Zhou Qin
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Bin Wu
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yu Yan
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yu-Wen Pei
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Ning-Ning Chao
- Institute of Respiratory Health, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Rui Zhang
- Department of Information Center, Engineering Research Center of Medical Information Technology of the Education Ministry, West China Hospital, Sichuan University, Chengdu, China
| | - Mi-Ye Wang
- Department of Information Center, Engineering Research Center of Medical Information Technology of the Education Ministry, West China Hospital, Sichuan University, Chengdu, China
| | - Ze-Hao Su
- Med-X Center for Informatics, West China Hospital, Sichuan University, Chengdu, China
| | - Xiao-Jun Lu
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Zhi-Yao He
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, China
| | - Ting Xu
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, Med-X Center for Informatics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, China
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18
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James AM, Seal SE, Bailey AM, Foster GD. Viral inosine triphosphatase: A mysterious enzyme with typical activity, but an atypical function. MOLECULAR PLANT PATHOLOGY 2021; 22:382-389. [PMID: 33471956 PMCID: PMC7865087 DOI: 10.1111/mpp.13021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/22/2020] [Accepted: 10/23/2020] [Indexed: 05/03/2023]
Abstract
Plant viruses typically have highly condensed genomes, yet the plant-pathogenic viruses Cassava brown streak virus, Ugandan cassava brown streak virus, and Euphorbia ringspot virus are unusual in encoding an enzyme not yet found in any other virus, the "house-cleaning" enzyme inosine triphosphatase. Inosine triphosphatases (ITPases) are highly conserved enzymes that occur in all kingdoms of life and perform a house-cleaning function by hydrolysing the noncanonical nucleotide inosine triphosphate to inosine monophosphate. The ITPases encoded by cassava brown streak virus and Ugandan cassava brown streak virus have been characterized biochemically and are shown to have typical ITPase activity. However, their biological role in virus infection has yet to be elucidated. Here we review what is known of viral-encoded ITPases and speculate on potential roles in infection with the aim of generating a greater understanding of cassava brown streak viruses, a group of the world's most devastating viruses.
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Affiliation(s)
- Amy M. James
- School of Biological SciencesLife Sciences BuildingUniversity of BristolBristolUK
| | - Susan E. Seal
- Natural Resources Institute, Chatham MaritimeGillinghamUK
| | - Andy M. Bailey
- School of Biological SciencesLife Sciences BuildingUniversity of BristolBristolUK
| | - Gary D. Foster
- School of Biological SciencesLife Sciences BuildingUniversity of BristolBristolUK
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19
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Amirinejad R, Shirvani-Farsani Z, Naghavi Gargari B, Sahraian MA, Mohammad Soltani B, Behmanesh M. Vitamin D changes expression of DNA repair genes in the patients with multiple sclerosis. Gene 2021; 781:145488. [PMID: 33588040 DOI: 10.1016/j.gene.2021.145488] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 01/18/2021] [Accepted: 02/02/2021] [Indexed: 12/31/2022]
Abstract
Oxidative stress (OS) plays an essential role in demyelination and tissue injury related to pathogenesis of multiple sclerosis (MS). On the other hand, vitamin D (VD) as an antioxidant reduces oxidative stress and has been used as adjuvant therapy in autoimmune diseases. Although VD supplementation is suggested as a protective and immunomodulation factor for MS patients, the molecular mechanisms remain unclear. Given that VD may modulate the immune system of MS patients through the DNA repair pathway, we aimed to evaluate the effects of VD supplementation in DNA repair genes expression including OGG1, MYH, MTH1, and ITPA. Transcript levels were measured using the RT-qPCR method in peripheral blood mononuclear cells (PBMCs) of relapsing-remitting multiple sclerosis (RRMS) patients before and after two months of VD supplementation. Furthermore, in silico analysis and correlation gene expression analysis was performed to find the biological binding sites and the effect of NRF2 on the regulation of DNA repair genes. Our data revealed that in MS patients, 2-month VD treatment significantly altered the expression of MYH, OGG1, MTH1, and NRF2 genes. A significant correlation was observed between DNA repair genes and NRF2 expression, which was confirmed by the presence of antioxidant response element (ARE) binding sites in the promoter of OGG1, MYH, and MTH1 genes. This study demonstrated that the impact of VD on MS patients may be mediated through the improvement of DNA repair system efficiency. This finding brought some new evidence for the involvement of DNA repair genes in the physiopathology of MS patients.
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Affiliation(s)
- Roya Amirinejad
- Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Zeinab Shirvani-Farsani
- Department of Cell and Molecular Biology, Faculty of Biological Sciences and Technology, Shahid Beheshti University G.C., Tehran, Iran
| | - Bahar Naghavi Gargari
- Department of Basic Sciences, Faculty Nursing and Midwifery Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohhamad Ali Sahraian
- MS Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Bahram Mohammad Soltani
- Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mehrdad Behmanesh
- Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
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20
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Sakamoto M, Kouhei D, Haniffa M, Silva S, Troncoso M, Santander P, Schonstedt V, Stecher X, Okamoto N, Hamanaka K, Mizuguchi T, Mitsuhashi S, Miyake N, Matsumoto N. A novel ITPA variant causes epileptic encephalopathy with multiple-organ dysfunction. J Hum Genet 2020; 65:751-757. [PMID: 32405030 DOI: 10.1038/s10038-020-0765-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/18/2020] [Accepted: 04/13/2020] [Indexed: 11/09/2022]
Abstract
Inborn errors of metabolism can cause epileptic encephalopathies. Biallelic loss-of-function variants in the ITPA gene, encoding inosine triphosphate pyrophosphatase (ITPase), have been reported in epileptic encephalopathies with lack of myelination of the posterior limb of the internal capsule, brainstem tracts, and tracts to the primary visual and motor cortices (MIM:616647). ITPase plays an important role in purine metabolism. In this study, we identified two novel homozygous ITPA variants, c.264-1 G > A and c.489-1 G > A, in two unrelated consanguineous families. The probands had epilepsy, microcephaly with characteristic magnetic resonance imaging findings (T2 hyperintensity signals in the pyramidal tracts of the internal capsule, delayed myelination, and thin corpus callosum), hypotonia, and developmental delay; both died in early infancy. Our report expands the knowledge of clinical consequences of biallelic ITPA variants.
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Affiliation(s)
- Masamune Sakamoto
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan.,Department of Pediatrics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Den Kouhei
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Muzhirah Haniffa
- Department of Genetics, Hospital Kuala Lumpur, Jalan Pahang, Malaysia
| | - Sebastián Silva
- Child Neurology Service, Hospital de Puerto Montt, Puerto Montt, Chile
| | - Mónica Troncoso
- Child Neurology Service, Hospital San Borja Arriarán, Universidad de Chile, Santiago, Chile
| | - Paola Santander
- Child Neurology Service, Hospital San Borja Arriarán, Universidad de Chile, Santiago, Chile
| | | | - Ximena Stecher
- Department of Radiology, Clínica Alemana de Santiago, Santiago, Chile.,Department of Radiology, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago, Chile
| | | | - Kohei Hamanaka
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Takeshi Mizuguchi
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Satomi Mitsuhashi
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Noriko Miyake
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan.
| | - Naomichi Matsumoto
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan.
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21
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Houndonougbo Y, Pugh B, VanWormer K, April C, Burgis N. Structural dynamics of inosine triphosphate pyrophosphatase (ITPA) protein and two clinically relevant mutants: molecular dynamics simulations. J Biomol Struct Dyn 2020; 39:1236-1247. [PMID: 32129147 DOI: 10.1080/07391102.2020.1727363] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The inosine triphosphate pyrophosphatase (ITPA) protein is responsible for removing noncanonical purine nucleoside triphosphates from intracellular nucleotide pools. Absence of ITPA results in genomic instability and increased levels of inosine in DNA and RNA. The proline to threonine substitution at position 32 (P32T) affects roughly 15% of the global population and can modulate treatment outcomes for cancer, lupus, and hepatitis C patients. The substitution of arginine with cysteine at position 178 (R178C) is extremely uncommon and has only been reported in a small cohort of early infantile encephalopathy patients suggesting that a functional ITPA protein is required for life in humans. Here we present molecular dynamic simulations that describe the structure and dynamics of the wild-type ITPA homodimer and two of its clinically relevant mutants, P32T and R178C. The simulation results indicate that both the P32T and R178C mutations alter the structure and dynamic properties of the protein and provide a possible explanation of the experimentally observed effect of the mutations on ITPA activity. Specifically, the mutations increased the overall flexibility of the protein and changed the dominant collective motions of the top lobe as well as the helix 2 of the lower lobe. Moreover, we have identified key active-site residues that are classified as essential or intermediate for inosine triphosphate (ITP) hydrolyzing activity based on their hydrogen bond occupancy. Here we also present biochemical data indicating that the R178C mutant has very low ITP hydrolyzing activity.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Yao Houndonougbo
- Department of Chemistry and Biochemistry, Eastern Washington University, Cheney, WA, USA
| | - Bethany Pugh
- Department of Chemistry and Biochemistry, Eastern Washington University, Cheney, WA, USA
| | - Kandise VanWormer
- Department of Chemistry and Biochemistry, Eastern Washington University, Cheney, WA, USA
| | - Caitlin April
- Department of Chemistry and Biochemistry, Eastern Washington University, Cheney, WA, USA
| | - Nicholas Burgis
- Department of Chemistry and Biochemistry, Eastern Washington University, Cheney, WA, USA
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22
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Kouwenberg TW, van den Bosch BJC, Bierau J, Te Loo DMWM, Coenen MJH, Hagleitner MM. Dosage of 6-Mercaptopurine in Relation to Genetic TPMT and ITPA Variants: Toward Individualized Pediatric Acute Lymphoblastic Leukemia Maintenance Treatment. J Pediatr Hematol Oncol 2020; 42:e94-e97. [PMID: 31895215 DOI: 10.1097/mph.0000000000001707] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
6-mercaptopurine (6-MP) is the mainstay in pediatric acute lymphoblastic leukemia (ALL) maintenance treatment. Variants in genes coding for thiopurine S-methyl transferase (TPMT) and inosine triphosphate pyrophosphatase (ITPA) are known to influence 6-MP metabolism. We determined TPMT and ITPA genotype and enzyme activity and the mean 6-MP doses during maintenance treatment in 40 children treated for ALL according to the Dutch Childhood Oncology Group (DCOG)-ALL11 protocol in the Radboudumc Amalia Children's Hospital, Nijmegen, The Netherlands. Patients with genetic variants in TPMT (N=3) had significantly lower TPMT enzyme activity (mean 0.46 vs. 0.72 µmol/mmol hemoglobin/h, P=0.005). Although the difference was not statistically significant, they were treated with lower mean 6-MP doses (28.1 mg/m [SD 25.5 mg/m] vs. 41.3 mg/m [SD 17.2 mg/m], P=0.375). In patients with genetic ITPA variants (N=21), ITPA enzyme activity was significantly lowered (mean 3.67 vs. 6.84 mmol/mmol hemoglobin/h, P<0.0005). The mean 6-MP doses did not differ between patients with and without variants in ITPA (40.0 mg/m [SD 20.3 mg/m] vs. 40.6 mg/m [SD 14.9 mg/m], P=0.663). The TPMT genotype, but not the ITPA genotype, should be considered as part of standard evaluation before starting ALL maintenance treatment.
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Affiliation(s)
- Theodorus W Kouwenberg
- Department of Pediatric Hematology and Oncology, Radboudumc Amalia Children's Hospital, Nijmegen
| | | | - Jörgen Bierau
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht
| | | | - Marieke J H Coenen
- Department of Human Genetics, Radboud Institute for Health Sciences, Radboudumc, Nijmegen
| | - Melanie M Hagleitner
- Department of Pediatric Hematology and Oncology, Radboudumc Amalia Children's Hospital, Nijmegen.,Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands
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23
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Kishibe M, Nozaki H, Fujii M, Iinuma S, Ohtsubo S, Igawa S, Kanno K, Honma M, Kishibe K, Okamoto K, Ishida-Yamamoto A. Severe thiopurine-induced leukocytopenia and hair loss in Japanese patients with defectiveNUDT15 variant: Retrospective case-control study. J Dermatol 2018; 45:1160-1165. [DOI: 10.1111/1346-8138.14588] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 07/03/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Mari Kishibe
- Department of Dermatology; Asahikawa Medical University; Asahikawa Japan
| | - Hiroyoshi Nozaki
- Department of Dermatology; Asahikawa Medical University; Asahikawa Japan
| | - Mizue Fujii
- Department of Dermatology; Asahikawa Medical University; Asahikawa Japan
| | - Shin Iinuma
- Department of Dermatology; Asahikawa Medical University; Asahikawa Japan
| | - Sawa Ohtsubo
- Department of Dermatology; Asahikawa Medical University; Asahikawa Japan
| | - Satomi Igawa
- Department of Dermatology; Asahikawa Medical University; Asahikawa Japan
| | - Kyoko Kanno
- Department of Dermatology; Asahikawa Medical University; Asahikawa Japan
| | - Masaru Honma
- Department of Dermatology; Asahikawa Medical University; Asahikawa Japan
| | - Kan Kishibe
- Department of Otorhinolaryngology; Asahikawa Medical University; Asahikawa Japan
| | - Kensaku Okamoto
- Division of Metabolism and Biosystemic Science; Department of Medicine; Asahikawa Medical University; Asahikawa Japan
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24
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Ji D, Stepchenkova EI, Cui J, Menezes MR, Pavlov YI, Kool ET. Measuring deaminated nucleotide surveillance enzyme ITPA activity with an ATP-releasing nucleotide chimera. Nucleic Acids Res 2017; 45:11515-11524. [PMID: 29036687 PMCID: PMC5714213 DOI: 10.1093/nar/gkx774] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 08/23/2017] [Indexed: 01/24/2023] Open
Abstract
Nucleotide quality surveillance enzymes play important roles in human health, by detecting damaged molecules in the nucleotide pool and deactivating them before they are incorporated into chromosomal DNA or adversely affect metabolism. In particular, deamination of adenine moiety in (deoxy)nucleoside triphosphates, resulting in formation of (d)ITP, can be deleterious, leading to DNA damage, mutagenesis and other harmful cellular effects. The 21.5 kDa human enzyme that mitigates this damage by conversion of (d)ITP to monophosphate, ITPA, has been proposed as a possible therapeutic and diagnostic target for multiple diseases. Measuring the activity of this enzyme is useful both in basic research and in clinical applications involving this pathway, but current methods are nonselective and are not applicable to measurement of the enzyme from cells or tissues. Here, we describe the design and synthesis of an ITPA-specific chimeric dinucleotide (DIAL) that replaces the pyrophosphate leaving group of the native substrate with adenosine triphosphate, enabling sensitive detection via luciferase luminescence signaling. The probe is shown to function sensitively and selectively to quantify enzyme activity in vitro, and can be used to measure the activity of ITPA in bacterial, yeast and human cell lysates.
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Affiliation(s)
- Debin Ji
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Elena I Stepchenkova
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Department of Genetics and Biotechnology, Saint-Petersburg State University, St Petersburg, 199034, Russia.,Saint-Petersburg Branch of Vavilov Institute of General Genetics, RAS, St Petersburg, 199034, Russia
| | - Jian Cui
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Miriam R Menezes
- Department of Neurosurgery, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Youri I Pavlov
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA.,Departments of Biochemistry and Molecular Biology; Microbiology and Pathology; Genetics Cell Biology and Anatomy; University of Nebraska Medical Center, Omaha, NE 61818, USA
| | - Eric T Kool
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
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25
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Jimmerson LC, Clayton CW, MaWhinney S, Meissner EG, Sims Z, Kottilil S, Kiser JJ. Effects of ribavirin/sofosbuvir treatment and ITPA phenotype on endogenous purines. Antiviral Res 2017; 138:79-85. [PMID: 27956135 PMCID: PMC10837792 DOI: 10.1016/j.antiviral.2016.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 11/23/2016] [Accepted: 12/03/2016] [Indexed: 12/15/2022]
Abstract
Ribavirin (RBV), a purine analog, causes hemolytic anemia in some patients. In vitro, anemia appears to result from depletion of endogenous purines, but there are limited data in vivo. Single nucleotide polymorphisms in the gene encoding the inosine triphosphatase (ITPA) enzyme have been associated with protection against RBV-induced anemia and may mediate the effect of RBV treatment on endogenous purines. The purpose of this work was to determine the effect of RBV treatment on endogenous purine concentrations in individuals being treated for chronic hepatitis C virus (HCV) infection. Adenosine triphosphate (ATP), guanosine triphosphate (GTP), inosine triphosphate (ITP) and ribavirin triphosphate (RTP) were measured in whole blood obtained from 47 HCV-infected individuals at day zero (baseline), day three, day 28 and day 84 of RBV/sofosbuvir (SOF) treatment. ATP decreased -35.1% and -38.6% (p < 0.0001) at day 28 and day 84 of treatment, respectively compared to baseline. The decrease in ATP was greater in patients with ≤60% ITPA activity compared to those with 100% ITPA activity (-29.4% vs. -9.6%). GTP did not change during treatment but was 16.5% (p = 0.01) higher per 100 pmol/106 cells RTP in those with 100% ITPA activity. No significant change or effect of RTP or ITPA phenotype was noted for ITP. In summary, only ATP was reduced by RBV/SOF treatment and ITPA variants had larger reductions in ATP suggesting RBV-induced anemia is due to a different mechanism than predicted from in-vitro studies. These data emphasize the importance of characterizing the effect of nucleos(t)ide analog treatment on endogenous purines in-vivo.
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Affiliation(s)
- Leah C Jimmerson
- University of Colorado, Skaggs School of Pharmacy and Pharmaceutical Sciences Aurora, CO, USA
| | | | | | - Eric G Meissner
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Zayani Sims
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Shyamasundaran Kottilil
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Jennifer J Kiser
- University of Colorado, Skaggs School of Pharmacy and Pharmaceutical Sciences Aurora, CO, USA.
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