1
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Wu B, Liu S. Structural Insights into the Mechanisms Underlying Polyaminopathies. Int J Mol Sci 2024; 25:6340. [PMID: 38928047 PMCID: PMC11203672 DOI: 10.3390/ijms25126340] [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: 05/12/2024] [Revised: 06/01/2024] [Accepted: 06/05/2024] [Indexed: 06/28/2024] Open
Abstract
Polyamines are ubiquitous in almost all biological entities and involved in various crucial physiological processes. They are also closely associated with the onset and progression of many diseases. Polyaminopathies are a group of rare genetic disorders caused by alterations in the function of proteins within the polyamine metabolism network. Although the identified polyaminopathies are all rare diseases at present, they are genetically heritable, rendering high risks not only to the carriers but also to their descendants. Meanwhile, more polyaminopathic patients might be discovered with the increasing accessibility of gene sequencing. This review aims to provide a comprehensive overview of the structural variations of mutated proteins in current polyaminopathies, in addition to their causative genes, types of mutations, clinical symptoms, and therapeutic approaches. We focus on analyzing how alterations in protein structure lead to protein dysfunction, thereby facilitating the onset of diseases. We hope this review will offer valuable insights and references for the future clinical diagnosis and precision treatment of polyaminopathies.
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Affiliation(s)
- Bing Wu
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Key Laboratory of Fermentation Engineering (Ministry of Education), Wuhan 430068, China
- Hubei Key Laboratory of Industrial Microbiology, National “111” Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan 430068, China
| | - Sen Liu
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Key Laboratory of Fermentation Engineering (Ministry of Education), Wuhan 430068, China
- Hubei Key Laboratory of Industrial Microbiology, National “111” Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan 430068, China
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2
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Bachmann AS, VanSickle EA, Michael J, Vipond M, Bupp CP. Bachmann-Bupp syndrome and treatment. Dev Med Child Neurol 2024; 66:445-455. [PMID: 37469105 PMCID: PMC10796844 DOI: 10.1111/dmcn.15687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/24/2023] [Accepted: 05/26/2023] [Indexed: 07/21/2023]
Abstract
Bachmann-Bupp syndrome (BABS) is a neurodevelopmental disorder characterized by developmental delay, hypotonia, and varying forms of non-congenital alopecia. The condition is caused by 3'-end mutations of the ornithine decarboxylase 1 (ODC1) gene, which produce carboxy (C)-terminally truncated variants of ODC, a pyridoxal 5'-phosphate-dependent enzyme. C-terminal truncation of ODC prevents its ubiquitin-independent proteasomal degradation and leads to cellular accumulation of ODC enzyme that remains catalytically active. ODC is the first rate-limiting enzyme that converts ornithine to putrescine in the polyamine pathway. Polyamines (putrescine, spermidine, spermine) are aliphatic molecules found in all forms of life and are important during embryogenesis, organogenesis, and tumorigenesis. BABS is an ultra-rare condition with few reported cases, but it serves as a convincing example for drug repurposing therapy. α-Difluoromethylornithine (DFMO, also known as eflornithine) is an ODC inhibitor with a strong safety profile in pediatric use for neuroblastoma and other cancers as well as West African sleeping sickness (trypanosomiasis). Patients with BABS have been treated with DFMO and have shown improvement in hair growth, muscle tone, and development.
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Affiliation(s)
- André S Bachmann
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI, USA
- International Center for Polyamine Disorders, Grand Rapids, MI, USA
| | - Elizabeth A VanSickle
- International Center for Polyamine Disorders, Grand Rapids, MI, USA
- Corewell Health, Helen DeVos Children's Hospital, Grand Rapids, MI, USA
| | - Julianne Michael
- International Center for Polyamine Disorders, Grand Rapids, MI, USA
- Corewell Health, Helen DeVos Children's Hospital, Grand Rapids, MI, USA
| | - Marlie Vipond
- International Center for Polyamine Disorders, Grand Rapids, MI, USA
- Corewell Health, Helen DeVos Children's Hospital, Grand Rapids, MI, USA
| | - Caleb P Bupp
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI, USA
- International Center for Polyamine Disorders, Grand Rapids, MI, USA
- Corewell Health, Helen DeVos Children's Hospital, Grand Rapids, MI, USA
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3
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Stewart TM, Foley JR, Holbert CE, Khomutov M, Rastkari N, Tao X, Khomutov AR, Zhai RG, Casero RA. Difluoromethylornithine rebalances aberrant polyamine ratios in Snyder-Robinson syndrome. EMBO Mol Med 2023; 15:e17833. [PMID: 37702369 PMCID: PMC10630878 DOI: 10.15252/emmm.202317833] [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: 04/10/2023] [Revised: 08/18/2023] [Accepted: 08/30/2023] [Indexed: 09/14/2023] Open
Abstract
Snyder-Robinson syndrome (SRS) results from mutations in spermine synthase (SMS), which converts the polyamine spermidine into spermine. Affecting primarily males, common manifestations of SRS include intellectual disability, osteoporosis, hypotonia, and seizures. Symptom management is the only treatment. Reduced SMS activity causes spermidine accumulation while spermine levels are reduced. The resulting exaggerated spermidine:spermine ratio is a biochemical hallmark of SRS that tends to correlate with symptom severity. Our studies aim to pharmacologically manipulate polyamine metabolism to correct this imbalance as a therapeutic strategy for SRS. Here we report the repurposing of 2-difluoromethylornithine (DFMO), an FDA-approved inhibitor of polyamine biosynthesis, in rebalancing spermidine:spermine ratios in SRS patient cells. Mechanistic in vitro studies demonstrate that, while reducing spermidine biosynthesis, DFMO also stimulates the conversion of spermidine into spermine in hypomorphic SMS cells and induces uptake of exogenous spermine, altogether reducing the aberrant ratios. In a Drosophila SRS model characterized by reduced lifespan, DFMO improves longevity. As nearly all SRS patient mutations are hypomorphic, these studies form a strong foundation for translational studies with significant therapeutic potential.
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Affiliation(s)
- Tracy Murray Stewart
- Sidney Kimmel Comprehensive Cancer CenterJohns Hopkins School of MedicineBaltimoreMDUSA
| | - Jackson R Foley
- Sidney Kimmel Comprehensive Cancer CenterJohns Hopkins School of MedicineBaltimoreMDUSA
| | - Cassandra E Holbert
- Sidney Kimmel Comprehensive Cancer CenterJohns Hopkins School of MedicineBaltimoreMDUSA
| | - Maxim Khomutov
- Engelhardt Institute of Molecular BiologyRussian Academy of SciencesMoscowRussia
| | - Noushin Rastkari
- Sidney Kimmel Comprehensive Cancer CenterJohns Hopkins School of MedicineBaltimoreMDUSA
| | - Xianzun Tao
- Department of Molecular and Cellular PharmacologyUniversity of Miami Miller School of MedicineMiamiFLUSA
| | - Alex R Khomutov
- Engelhardt Institute of Molecular BiologyRussian Academy of SciencesMoscowRussia
| | - R Grace Zhai
- Department of Molecular and Cellular PharmacologyUniversity of Miami Miller School of MedicineMiamiFLUSA
| | - Robert A Casero
- Sidney Kimmel Comprehensive Cancer CenterJohns Hopkins School of MedicineBaltimoreMDUSA
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4
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Stewart TRM, Foley JR, Holbert CE, Khomutov MA, Rastkari N, Tao X, Khomutov AR, Zhai RG, Casero RA. Difluoromethylornithine rebalances aberrant polyamine ratios in Snyder-Robinson syndrome: mechanism of action and therapeutic potential. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.30.534977. [PMID: 37034775 PMCID: PMC10081208 DOI: 10.1101/2023.03.30.534977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Snyder-Robinson Syndrome (SRS) is caused by mutations in the spermine synthase (SMS) gene, the enzyme product of which converts the polyamine spermidine into spermine. Affecting primarily males, common manifestations of SRS include intellectual disability, osteoporosis, hypotonic musculature, and seizures, along with other more variable symptoms. Currently, medical management focuses on treating these symptoms without addressing the underlying molecular cause of the disease. Reduced SMS catalytic activity in cells of SRS patients causes the accumulation of spermidine, while spermine levels are reduced. The resulting exaggeration in spermidine-to-spermine ratio is a biochemical hallmark of SRS that tends to correlate with symptom severity in the patient. Our studies aim to pharmacologically manipulate polyamine metabolism to correct this polyamine imbalance and investigate the potential of this approach as a therapeutic strategy for affected individuals. Here we report the use of difluoromethylornithine (DFMO; eflornithine), an FDA-approved inhibitor of polyamine biosynthesis, in re-establishing normal spermidine-to-spermine ratios in SRS patient cells. Through mechanistic studies, we demonstrate that, while reducing spermidine biosynthesis, DFMO also stimulates the conversion of existing spermidine into spermine in cell lines with hypomorphic variants of SMS. Further, DFMO treatment induces a compensatory uptake of exogenous polyamines, including spermine and spermine mimetics, cooperatively reducing spermidine and increasing spermine levels. In a Drosophila SRS model characterized by reduced lifespan, adding DFMO to the feed extended lifespan. As nearly all known SRS patient mutations are hypomorphic, these studies form a foundation for future translational studies with significant therapeutic potential.
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5
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Michael J, VanSickle E, Vipond M, Dalman A, Prokop J, Schwartz CE, Rajasekaran S, Bachmann AS, Barth M, Prouteau C, Almagor Y, Berkun L, Alterescu G, Bupp CP. Two New Cases of Bachmann-Bupp Syndrome Identified through the International Center for Polyamine Disorders. Med Sci (Basel) 2023; 11:29. [PMID: 37092498 PMCID: PMC10123676 DOI: 10.3390/medsci11020029] [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: 03/15/2023] [Revised: 03/29/2023] [Accepted: 03/29/2023] [Indexed: 04/07/2023] Open
Abstract
Recent identification of four additional polyaminopathies, including Bachmann-Bupp syndrome, have benefited from previous research on Snyder-Robinson syndrome in order to advance from research to treatment more quickly. As a result of the discovery of these conditions, the potential for treatment within this pathway, and for other possible unidentified polyaminopathies, the International Center for Polyamine Disorders (ICPD) was created to help promote understanding of these conditions, research opportunities, and appropriate care for families. This case study provides insights from two new patients diagnosed with Bachmann-Bupp syndrome, further expanding our understanding of this ultra-rare condition, as well as a general discussion about other known polyaminopathies. This work also presents considerations for collaborative research efforts across these conditions, along with others that are likely to be identified in time, and outlines the role that the ICPD hopes to fill as more patients with these polyaminopathies continue to be identified and diagnosed.
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Affiliation(s)
- Julianne Michael
- Corewell Health and Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA
- International Center for Polyamine Disorders, Grand Rapids, MI 49503, USA
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
| | - Elizabeth VanSickle
- Corewell Health and Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA
- International Center for Polyamine Disorders, Grand Rapids, MI 49503, USA
| | - Marlie Vipond
- Corewell Health and Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA
- International Center for Polyamine Disorders, Grand Rapids, MI 49503, USA
| | - Abby Dalman
- Corewell Health and Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA
| | - Jeremy Prokop
- Corewell Health and Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA
| | - Charles E. Schwartz
- International Center for Polyamine Disorders, Grand Rapids, MI 49503, USA
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
| | - Surender Rajasekaran
- Corewell Health and Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA
- International Center for Polyamine Disorders, Grand Rapids, MI 49503, USA
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
| | - André S. Bachmann
- International Center for Polyamine Disorders, Grand Rapids, MI 49503, USA
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
| | - Magalie Barth
- Department of Biochemistry and Genetics, Angers University Hospital Center, 49100 Angers, France
| | - Clément Prouteau
- Department of Biochemistry and Genetics, Angers University Hospital Center, 49100 Angers, France
| | | | - Lina Berkun
- Shaare Zedek Medical Center, Medical Genetics Institute, Jerusalem 9103102, Israel
| | - Gheona Alterescu
- Shaare Zedek Medical Center, Medical Genetics Institute, Jerusalem 9103102, Israel
| | - Caleb P. Bupp
- Corewell Health and Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA
- International Center for Polyamine Disorders, Grand Rapids, MI 49503, USA
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
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6
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Schultz CR, Sheldon RD, Xie H, Demireva EY, Uhl KL, Agnew DW, Geerts D, Bachmann AS. New K50R mutant mouse models reveal impaired hypusination of eif5a2 with alterations in cell metabolite landscape. Biol Open 2023; 12:290754. [PMID: 36848144 PMCID: PMC10084858 DOI: 10.1242/bio.059647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 02/21/2023] [Indexed: 03/01/2023] Open
Abstract
The eukaryotic translation initiation factor 5A1 (eIF5A1) and 5A2 (eIF5A2) are important proteins in a variety of physiological and pathophysiological processes and their function has been linked to neurodevelopmental disorders, cancer, and viral infections. Here, we report two new genome-edited mouse models, generated using a CRISPR-Cas9 approach, in which the amino acid residue lysine 50 is replaced with arginine 50 (K50R) in eIF5A1 or in the closely related eIF5A2 protein. This mutation prevents the spermidine-dependent post-translational formation of hypusine, a unique lysine derivative that is necessary for activation of eIF5A1 and eIF5A2. Mouse brain lysates from homozygous eif5a2-K50R mutant mice (eif5a2K50R/K50R) confirmed the absence of hypusine formation of eIF5A2, and metabolomic analysis of primary mouse dermal fibroblasts revealed significant alterations in the metabolite landscape compared to controls including increased levels of tryptophan, kyrunenine, pyridoxine, nicotinamide adenine dinucleotide, riboflavin, flavin adenine dinucleotide, pantothenate, and coenzyme A. Further supported by new publicly available bioinformatics data, these new mouse models represent excellent in vivo models to study hypusine-dependent biological processes, hypusination-related disorders caused by eIF5A1 and eIF5A2 gene aberrations or mRNA expression dysregulation, as well as several major human cancer types and potential therapies.
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Affiliation(s)
- Chad R Schultz
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
| | - Ryan D Sheldon
- Core Technologies and Services, Mass Spectrometry Core, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Huirong Xie
- Transgenic and Genome Editing Facility, Institute for Quantitative Health Science and Engineering, Research Technology Support Facility, Michigan State University, East Lansing, MI 48824, USA
| | - Elena Y Demireva
- Transgenic and Genome Editing Facility, Institute for Quantitative Health Science and Engineering, Research Technology Support Facility, Michigan State University, East Lansing, MI 48824, USA
| | - Katie L Uhl
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
| | - Dalen W Agnew
- Department of Pathobiology & Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
| | - Dirk Geerts
- Department of Hematology, Amsterdam University Medical Center, Location VUMC, 1081 HV Amsterdam, The Netherlands
| | - André S Bachmann
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
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7
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Colonna MB, Moss T, Mokashi S, Srikanth S, Jones JR, Foley JR, Skinner C, Lichty A, Kocur A, Wood T, Stewart TM, Casero Jr. RA, Flanagan-Steet H, Edison AS, Lyons MJ, Steet R. Functional assessment of homozygous ALDH18A1 variants reveals alterations in amino acid and antioxidant metabolism. Hum Mol Genet 2023; 32:732-744. [PMID: 36067040 PMCID: PMC9941824 DOI: 10.1093/hmg/ddac226] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/08/2022] [Accepted: 09/01/2022] [Indexed: 11/13/2022] Open
Abstract
Mono- and bi-allelic variants in ALDH18A1 cause a spectrum of human disorders associated with cutaneous and neurological findings that overlap with both cutis laxa and spastic paraplegia. ALDH18A1 encodes the bifunctional enzyme pyrroline-5-carboxylate synthetase (P5CS) that plays a role in the de novo biosynthesis of proline and ornithine. Here we characterize a previously unreported homozygous ALDH18A1 variant (p.Thr331Pro) in four affected probands from two unrelated families, and demonstrate broad-based alterations in amino acid and antioxidant metabolism. These four patients exhibit variable developmental delay, neurological deficits and loose skin. Functional characterization of the p.Thr331Pro variant demonstrated a lack of any impact on the steady-state level of the P5CS monomer or mitochondrial localization of the enzyme, but reduced incorporation of the monomer into P5CS oligomers. Using an unlabeled NMR-based metabolomics approach in patient fibroblasts and ALDH18A1-null human embryonic kidney cells expressing the variant P5CS, we identified reduced abundance of glutamate and several metabolites derived from glutamate, including proline and glutathione. Biosynthesis of the polyamine putrescine, derived from ornithine, was also decreased in patient fibroblasts, highlighting the functional consequence on another metabolic pathway involved in antioxidant responses in the cell. RNA sequencing of patient fibroblasts revealed transcript abundance changes in several metabolic and extracellular matrix-related genes, adding further insight into pathogenic processes associated with impaired P5CS function. Together these findings shed new light on amino acid and antioxidant pathways associated with ALDH18A1-related disorders, and underscore the value of metabolomic and transcriptomic profiling to discover new pathways that impact disease pathogenesis.
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Affiliation(s)
- Maxwell B Colonna
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Tonya Moss
- Greenwood Genetic Center, Greenwood, SC 29646, USA
| | | | | | | | - Jackson R Foley
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine; Baltimore, MD 21287, USA
| | | | - Angie Lichty
- Greenwood Genetic Center, Greenwood, SC 29646, USA
| | | | - Tim Wood
- Department of Pathology and Laboratory Medicine, Children’s Hospital Colorado, Aurora, CO 80045, USA
| | - Tracy Murray Stewart
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine; Baltimore, MD 21287, USA
| | - Robert A Casero Jr.
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine; Baltimore, MD 21287, USA
| | | | - Arthur S Edison
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
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8
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Hofer SJ, Simon AK, Bergmann M, Eisenberg T, Kroemer G, Madeo F. Mechanisms of spermidine-induced autophagy and geroprotection. NATURE AGING 2022; 2:1112-1129. [PMID: 37118547 DOI: 10.1038/s43587-022-00322-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 10/28/2022] [Indexed: 04/30/2023]
Abstract
Aging involves the systemic deterioration of all known cell types in most eukaryotes. Several recently discovered compounds that extend the healthspan and lifespan of model organisms decelerate pathways that govern the aging process. Among these geroprotectors, spermidine, a natural polyamine ubiquitously found in organisms from all kingdoms, prolongs the lifespan of fungi, nematodes, insects and rodents. In mice, it also postpones the manifestation of various age-associated disorders such as cardiovascular disease and neurodegeneration. The specific features of spermidine, including its presence in common food items, make it an interesting candidate for translational aging research. Here, we review novel insights into the geroprotective mode of action of spermidine at the molecular level, as we discuss strategies for elucidating its clinical potential.
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Affiliation(s)
- Sebastian J Hofer
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Centre de Recherche des Cordeliers, Equipe labellisée par la Ligue contre le cancer, Université de Paris Cité, Sorbonne Université, Inserm U1138, Institut Universitaire de France, Paris, France
- Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif, France
| | - Anna Katharina Simon
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
- Max Delbrück Center, Berlin, Germany
| | - Martina Bergmann
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - Tobias Eisenberg
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
| | - Guido Kroemer
- Centre de Recherche des Cordeliers, Equipe labellisée par la Ligue contre le cancer, Université de Paris Cité, Sorbonne Université, Inserm U1138, Institut Universitaire de France, Paris, France.
- Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif, France.
- Institut du Cancer Paris CARPEM, Department of Biology, Hôpital Européen Georges Pompidou, AP-HP, Paris, France.
| | - Frank Madeo
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria.
- Field of Excellence BioHealth, University of Graz, Graz, Austria.
- BioTechMed Graz, Graz, Austria.
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9
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Afrin A, Afshan TS, VanSickle EA, Michael J, Laarman RL, Bupp CP. Improvement of dermatological symptoms in patients with Bachmann-Bupp syndrome using difluoromethylornithine treatment. Pediatr Dermatol 2022; 40:528-531. [PMID: 36443247 DOI: 10.1111/pde.15187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 10/16/2022] [Indexed: 12/03/2022]
Abstract
Bachmann-Bupp syndrome (OMIM #619075) is a novel autosomal dominant disorder caused by variants in the c-terminus of the ornithine decarboxylase 1 gene, resulting in increased levels of ornithine decarboxylase. This case report includes two patients diagnosed with Bachmann-Bupp syndrome who were treated with difluoromethylornithine through compassionate use approval from the United States Food and Drug Administration. In both patients, treatment with difluoromethylornithine has resulted in improved dermatologic signs, including regrowth of eyebrow and scalp hair and cessation of recurrent follicular cyst development.
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Affiliation(s)
- Antara Afrin
- College of Human Medicine, Michigan State University, Grand Rapids, Michigan, USA
| | - Tonia S Afshan
- Pediatric Residency Program, Spectrum Health/Michigan State University/Helen DeVos Children's Hospital, Grand Rapids, Michigan, USA.,Division of Allergy, Pulmonary, and Critical Care, Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Elizabeth A VanSickle
- Division of Medical Genetics and Genomics, Spectrum Health and Helen DeVos Children's Hospital, Grand Rapids, Michigan, USA.,International Center for Polyamine Disorders, Grand Rapids, Michigan, USA
| | - Julianne Michael
- Division of Medical Genetics and Genomics, Spectrum Health and Helen DeVos Children's Hospital, Grand Rapids, Michigan, USA.,International Center for Polyamine Disorders, Grand Rapids, Michigan, USA
| | - Rachel L Laarman
- Division of Medical Subspecialties, Section of Dermatology, Helen DeVos Children's Hospital, Grand Rapids, Michigan, USA
| | - Caleb P Bupp
- College of Human Medicine, Michigan State University, Grand Rapids, Michigan, USA.,Division of Medical Genetics and Genomics, Spectrum Health and Helen DeVos Children's Hospital, Grand Rapids, Michigan, USA.,International Center for Polyamine Disorders, Grand Rapids, Michigan, USA
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10
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Zhou XE, Schultz CR, Suino Powell K, Henrickson A, Lamp J, Brunzelle JS, Demeler B, Vega IE, Bachmann AS, Melcher K. Structure and Enzymatic Activity of an Intellectual Disability-Associated Ornithine Decarboxylase Variant, G84R. ACS OMEGA 2022; 7:34665-34675. [PMID: 36188294 PMCID: PMC9520691 DOI: 10.1021/acsomega.2c04702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 08/30/2022] [Indexed: 06/13/2023]
Abstract
Ornithine decarboxylase (ODC) is a rate-limiting enzyme for the synthesis of polyamines (PAs). PAs are required for proliferation, and increased ODC activity is associated with cancer and neural over-proliferation. ODC levels and activity are therefore tightly regulated, including through the ODC-specific inhibitor, antizyme AZ1. Recently, ODC G84R has been reported as a partial loss-of-function variant that is associated with intellectual disability and seizures. However, G84 is distant from both the catalytic center and the ODC homodimerization interface. To understand how G84R modulates ODC activity, we have determined the crystal structure of ODC G84R in both the presence and the absence of the cofactor pyridoxal 5-phosphate. The structures show that the replacement of G84 by arginine leads to hydrogen bond formation of R84 with F420, the last residue of the ODC C-terminal helix, a structural element that is involved in the AZ1-mediated proteasomal degradation of ODC. In contrast, the catalytic center is essentially indistinguishable from that of wildtype ODC. We therefore reanalyzed the catalytic activity of ODC G84R and found that it is rescued when the protein is purified in the presence of a reducing agent to mimic the reducing environment of the cytoplasm. This suggests that R84 may exert its neurological effects not through reducing ODC catalytic activity but through misregulation of its AZ1-mediated proteasomal degradation.
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Affiliation(s)
- X. Edward Zhou
- Department
of Structural Biology, Van Andel Institute, Grand Rapids, Michigan 49503, United States
| | - Chad R. Schultz
- Department
of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, Michigan 49546, United States
| | - Kelly Suino Powell
- Department
of Structural Biology, Van Andel Institute, Grand Rapids, Michigan 49503, United States
| | - Amy Henrickson
- Department
of Chemistry and Biochemistry, The University
of Lethbridge, Lethbridge, AB T1K3M4, Canada
| | - Jared Lamp
- Department
of Translational Neuroscience, Integrated Mass Spectrometry Unit,
College of Human Medicine, Michigan State
University, Grand
Rapids, Michigan 49503, United States
| | - Joseph S. Brunzelle
- Northwestern
University Synchrotron Research Center, Life Sciences Collaborative
Access Team, Northwestern University, Argonne, Illinois 60439, United States
| | - Borries Demeler
- Department
of Chemistry and Biochemistry, The University
of Lethbridge, Lethbridge, AB T1K3M4, Canada
- Department
of Chemistry and Biochemistry, The University
of Montana, Missoula, Montana 59812, United
States
| | - Irving E. Vega
- Department
of Translational Neuroscience, Integrated Mass Spectrometry Unit,
College of Human Medicine, Michigan State
University, Grand
Rapids, Michigan 49503, United States
| | - André S. Bachmann
- Department
of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, Michigan 49546, United States
| | - Karsten Melcher
- Department
of Structural Biology, Van Andel Institute, Grand Rapids, Michigan 49503, United States
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