1
|
Jiachen Z, Paul Kwong Hang T, Kenneth Kak Yuen W, Vincent Chi Hang L. Pathological role of methionine in the initiation and progression of biliary atresia. Front Pediatr 2023; 11:1263836. [PMID: 37772039 PMCID: PMC10522914 DOI: 10.3389/fped.2023.1263836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 08/21/2023] [Indexed: 09/30/2023] Open
Abstract
Methionine (Met) is an essential amino acid, and its excessive dietary intake and/or its metabolism disturbance could lead to accumulation/depletion of hepatic Met and some of the key intermediates of these pathways, which would interfere normal liver function and would be associated with liver diseases. Biliary atresia (BA) is a life-threatening disease characterized by inflammatory fibrosclerosing changes of the intrahepatic and extrahepatic biliary systems and is the primary cause of obstructive neonatal cholestasis with a rapid course of liver failure. However, its pathogenesis remains unknown. Previous studies reported elevated Met level in patients with obstructive cholestasis, suggesting a potential link between Met and BA. This paper reviews the Met metabolism in normal conditions and its dysregulation under abnormal conditions, the possible causes of hypermethioninemia, and its connection to BA pathogenesis: Abnormal hepatic level of Met could lead to a perturbation of redox homeostasis and mitochondrial functions of hepatocytes, enhancement of viral infectivity, and dysregulation of innate and adaptative immune cells in response to infection/damage of the liver contributing to the initiation/progression of BA.
Collapse
Affiliation(s)
- Zheng Jiachen
- Department of Surgery, School of Clinical Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Tam Paul Kwong Hang
- Faculty of Medicine, Macau University of Science and Technology, Macau, Macau SAR, China
| | - Wong Kenneth Kak Yuen
- Department of Surgery, School of Clinical Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
- Department of Surgery, University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Lui Vincent Chi Hang
- Department of Surgery, School of Clinical Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
- Dr. Li Dak-Sum Research Centre, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| |
Collapse
|
2
|
Tong F, Zhang Y, Chen C, Zhu L, Lu Y, Zhang Z, Chen T, Yan J, Zheng J, Zhao X, Zhou D, Yang X, Yang R, Cang X, Jiang P, Shu Q. Long-term prognosis of 35 patients with methionine adenosyltransferase deficiency based on newborn screening in China. Front Cell Dev Biol 2023; 10:1059680. [PMID: 36704196 PMCID: PMC9871361 DOI: 10.3389/fcell.2022.1059680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 12/23/2022] [Indexed: 01/12/2023] Open
Abstract
Methionine adenosyltransferase deficiency (MATD) is a rare metabolic disorder caused by mono- or biallelic MAT1A mutations that are not yet well understood. Of the 4,065,644 neonates screened between November 2010 and December 2021, 35 individuals have been diagnosed with an estimated incidence of 1: 116,161 by a cutoff value of methionine 82.7 μmol/L and follow-up over 11 years. MATD patients with autosomal recessive (AR) type had higher clinical and genetic heterogeneity than those with autosomal dominant (AD) type. Fifteen unrelated AD patients harbored one well-known dominant variant, c.791 G>A or c.776 C>T, and were clinically unaffected with a mean plasma methionine (Met) value <300 μmol/L. Twenty AR cases have unique genotypes and presented a wide range of clinical abnormalities from asymptomatic to white matter lesions. Of them, 10 AR patients displayed severe manifestations, such as verbal difficulty, motor delay, development delay, and white matter lesions, with mean Met >500 μmol/L and thereby were treated with a methionine-restricted diet alone or in combination with betaine, folate, or vitamin B6, and were healthy finally. Neurological abnormalities were evidenced in two patients (P16 and P27) with Met values >800 μmol/L by MRI scan. Neurological abnormalities were reversed here by liver transplantation or by the determination of S-adenosylmethionine supplementation. Additionally, 38 variants of MAT1A were distributed within patients and carriers, of which 24 were novel and mostly predicted to be damaged. Our findings with an extensive clinical and genetic dataset provided new insights into its diagnosis and treatment and will be helpful for its optimal management in the future.
Collapse
Affiliation(s)
- Fan Tong
- Department of Genetics and Metabolism, The Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuchen Zhang
- Department of Genetics and Metabolism, The Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, China
| | - Chi Chen
- Department of Genetics and Metabolism, The Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China
| | - Ling Zhu
- Department of Genetics and Metabolism, The Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China
| | - Yijun Lu
- Department of Genetics and Metabolism, The Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhanming Zhang
- Department of Genetics and Metabolism, The Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China
| | - Ting Chen
- Department of Genetics and Metabolism, The Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China
| | - Jiaxuan Yan
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, China
| | - Jing Zheng
- Department of Genetics and Metabolism, The Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoxu Zhao
- Department of Genetics and Metabolism, The Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China
| | - Duo Zhou
- Department of Genetics and Metabolism, The Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China
| | - Xin Yang
- Department of Genetics and Metabolism, The Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China
| | - Rulai Yang
- Department of Genetics and Metabolism, The Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaohui Cang
- Department of Genetics and Metabolism, The Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, China
| | - Pingping Jiang
- Department of Genetics and Metabolism, The Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, China,*Correspondence: Qiang Shu, ; Pingping Jiang,
| | - Qiang Shu
- Department of Genetics and Metabolism, The Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada,*Correspondence: Qiang Shu, ; Pingping Jiang,
| |
Collapse
|
3
|
Hübner V, Hannibal L, Janzen N, Grünert SC, Freisinger P. Methionine Adenosyltransferase I/III Deficiency Detected by Newborn Screening. Genes (Basel) 2022; 13:genes13071163. [PMID: 35885946 PMCID: PMC9323693 DOI: 10.3390/genes13071163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 06/22/2022] [Indexed: 11/21/2022] Open
Abstract
Methionine adenosyltransferase I/III deficiency is an inborn error of metabolism due to mutations in the MAT1A gene. It is the most common cause of hypermethioninemia in newborn screening. Heterozygotes are often asymptomatic. In contrast, homozygous or compound heterozygous individuals can develop severe neurological symptoms. Less than 70 cases with biallelic variants have been reported worldwide. A methionine-restricted diet is recommended if methionine levels are above 500−600 µmol/L. In this study, we report on a female patient identified with elevated methionine concentrations in a pilot newborn screening program. The patient carries a previously described variant c.1132G>A (p.Gly378Ser) in homozygosity. It is located at the C-terminus of MAT1A. In silico analysis suggests impaired protein stability by β-turn disruption. On a methionine-restricted diet, her serum methionine concentration ranged between 49−605 µmol/L (median 358 µmol/L). Her clinical course was characterized by early-onset muscular hypotonia, mild developmental delay, delayed myelination and mild periventricular diffusion interference in MRI. At 21 months, the girl showed age-appropriate neurological development, but progressive diffusion disturbances in MRI. Little is known about the long-term outcome of this disorder and the necessity of treatment. Our case demonstrates that neurological symptoms can be transient and even patients with initial neurologic manifestations can show normal development under dietary management.
Collapse
Affiliation(s)
- Vanessa Hübner
- Department of Pediatrics, Metabolic Disease Center, Klinikum Reutlingen, Steinenbergstr. 31, 72764 Reutlingen, Germany;
- Correspondence: (V.H.); (S.C.G.)
| | - Luciana Hannibal
- Department of General Pediatrics, Adolescent Medicine and Neonatology, University Medical Center, Faculty of Medicine, University of Freiburg, Mathildenstraße 1, 79106 Freiburg, Germany;
| | - Nils Janzen
- Screening Laboratory Hannover, Box 91 10 09, 30430 Hannover, Germany;
- Division of Laboratory Medicine, Centre for Children and Adolescents, Kinder- und Jugendkrankenhaus Auf der Bult, Janusz-Korczak-Allee 12, 30173 Hannover, Germany
- Department of Clinical Chemistry, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Sarah Catharina Grünert
- Department of General Pediatrics, Adolescent Medicine and Neonatology, University Medical Center, Faculty of Medicine, University of Freiburg, Mathildenstraße 1, 79106 Freiburg, Germany;
- Correspondence: (V.H.); (S.C.G.)
| | - Peter Freisinger
- Department of Pediatrics, Metabolic Disease Center, Klinikum Reutlingen, Steinenbergstr. 31, 72764 Reutlingen, Germany;
| |
Collapse
|
4
|
Sánchez-Pérez GF, Pajares MÁ. Polar Interactions at the Dimer-Dimer Interface of Methionine Adenosyltransferase MAT I Control Tetramerization. Int J Mol Sci 2021; 22:13206. [PMID: 34948004 DOI: 10.3390/ijms222413206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 11/29/2021] [Accepted: 12/06/2021] [Indexed: 11/17/2022] Open
Abstract
Catalytic MATα1 subunits associate into kinetically distinct homo-dimers (MAT III) and homo-tetramers (MAT I) that synthesize S-adenosylmethionine in the adult liver. Pathological reductions in S-adenosylmethionine levels correlate with MAT III accumulation; thus, it is important to know the determinants of dimer–dimer associations. Here, polar interactions (<3.5 Å) at the rat MAT I dimer–dimer interface were disrupted by site-directed mutagenesis. Heterologous expression rendered decreased soluble mutant MATα1 levels that appeared mostly as dimers. Substitutions at the B1–B2 or B3–C1 β-strand loops, or changes in charge on helix α2 located behind, induced either MAT III or MAT I accumulation. Notably, double mutants combining neutral changes on helix α2 with substitutions at either β-strand loop further increased MAT III content. Mutations had negligible impact on secondary or tertiary protein structure, but induced changes of 5–10 °C in thermal stability. All mutants preserved tripolyphosphatase activity, although AdoMet synthesis was only detected in single mutants. Kinetic parameters were altered in all purified proteins, their AdoMet synthesis Vmax and methionine affinities correlating with the association state induced by the corresponding mutations. In conclusion, polar interactions control MATα1 tetramerization and kinetics, diverse effects being induced by changes on opposite β-sheet loops putatively leading to subtle variations in central domain β-sheet orientation.
Collapse
|
5
|
Luciano-Mateo F, Cabré N, Baiges-Gaya G, Fernández-Arroyo S, Hernández-Aguilera A, Elisabet Rodríguez-Tomàs E, Arenas M, Camps J, Menéndez JA, Joven J. Systemic overexpression of C-C motif chemokine ligand 2 promotes metabolic dysregulation and premature death in mice with accelerated aging. Aging (Albany NY) 2020; 12:20001-20023. [PMID: 33104522 PMCID: PMC7655213 DOI: 10.18632/aging.104154] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 08/24/2020] [Indexed: 12/26/2022]
Abstract
Injection of tissues with senescent cells induces changes that mimic aging, and this process is delayed in mice engineered to eliminate senescent cells, which secrete proinflammatory cytokines, including C-C motif chemokine ligand 2 (Ccl2). Circulating levels of Ccl2 correlate with age, but the impact of Ccl2 on tissue homeostasis has not been established. We generated an experimental model by crossbreeding mice overexpressing Ccl2 with progeroid mice bearing a mutation in the lamin A (Lmna) gene. Wild-type animals and progeroid mice that do not overexpress Ccl2 were used as controls. Ccl2 overexpression decreased the lifespan of the progeroid mice and induced the dysregulation of glycolysis, the citric acid cycle and one-carbon metabolism in skeletal muscle, driving dynamic changes in energy metabolism and DNA methylation. This impact on cellular bioenergetics was associated with mitochondrial alterations and affected cellular metabolism, autophagy and protein synthesis through AMPK/mTOR pathways. The data revealed the ability of Ccl2 to promote death in mice with accelerated aging, which supports its putative use as a biomarker of an increased senescent cell burden and for the assessment of the efficacy of interventions aimed at extending healthy aging.
Collapse
Affiliation(s)
- Fedra Luciano-Mateo
- Universitat Rovira i Virgili, Department of Medicine and Surgery, Reus 43201, Spain.,Unitat de Recerca Biomèdica, Hospital Universitari Sant Joan, Institut d'Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus 43201, Spain
| | - Noemí Cabré
- Universitat Rovira i Virgili, Department of Medicine and Surgery, Reus 43201, Spain.,Unitat de Recerca Biomèdica, Hospital Universitari Sant Joan, Institut d'Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus 43201, Spain
| | - Gerard Baiges-Gaya
- Universitat Rovira i Virgili, Department of Medicine and Surgery, Reus 43201, Spain.,Unitat de Recerca Biomèdica, Hospital Universitari Sant Joan, Institut d'Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus 43201, Spain
| | - Salvador Fernández-Arroyo
- Universitat Rovira i Virgili, Department of Medicine and Surgery, Reus 43201, Spain.,Unitat de Recerca Biomèdica, Hospital Universitari Sant Joan, Institut d'Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus 43201, Spain
| | - Anna Hernández-Aguilera
- Unitat de Recerca Biomèdica, Hospital Universitari Sant Joan, Institut d'Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus 43201, Spain
| | - Elisabet Elisabet Rodríguez-Tomàs
- Unitat de Recerca Biomèdica, Hospital Universitari Sant Joan, Institut d'Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus 43201, Spain
| | - Meritxell Arenas
- Department of Radiation Oncology, Hospital Universitari Sant Joan, Institut d’Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus 43204, Spain
| | - Jordi Camps
- Universitat Rovira i Virgili, Department of Medicine and Surgery, Reus 43201, Spain.,Unitat de Recerca Biomèdica, Hospital Universitari Sant Joan, Institut d'Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus 43201, Spain
| | - Javier A Menéndez
- Program Against Cancer Therapeutic Resistance (ProCURE), Metabolism and Cancer Group, Catalan Institute of Oncology, Girona 17007, Spain.,Girona Biomedical Research Institute (IDIBGI), Girona 17190, Spain
| | - Jorge Joven
- Universitat Rovira i Virgili, Department of Medicine and Surgery, Reus 43201, Spain.,Unitat de Recerca Biomèdica, Hospital Universitari Sant Joan, Institut d'Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus 43201, Spain.,The Campus of International Excellence Southern Catalonia, Tarragona 43003, Spain
| |
Collapse
|
6
|
Kožich V, Stabler S. Lessons Learned from Inherited Metabolic Disorders of Sulfur-Containing Amino Acids Metabolism. J Nutr 2020; 150:2506S-2517S. [PMID: 33000152 DOI: 10.1093/jn/nxaa134] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 03/12/2020] [Accepted: 04/17/2020] [Indexed: 12/16/2022] Open
Abstract
The metabolism of sulfur-containing amino acids (SAAs) requires an orchestrated interplay among several dozen enzymes and transporters, and an adequate dietary intake of methionine (Met), cysteine (Cys), and B vitamins. Known human genetic disorders are due to defects in Met demethylation, homocysteine (Hcy) remethylation, or cobalamin and folate metabolism, in Hcy transsulfuration, and Cys and hydrogen sulfide (H2S) catabolism. These disorders may manifest between the newborn period and late adulthood by a combination of neuropsychiatric abnormalities, thromboembolism, megaloblastic anemia, hepatopathy, myopathy, and bone and connective tissue abnormalities. Biochemical features include metabolite deficiencies (e.g. Met, S-adenosylmethionine (AdoMet), intermediates in 1-carbon metabolism, Cys, or glutathione) and/or their accumulation (e.g. S-adenosylhomocysteine, Hcy, H2S, or sulfite). Treatment should be started as early as possible and may include a low-protein/low-Met diet with Cys-enriched amino acid supplements, pharmacological doses of B vitamins, betaine to stimulate Hcy remethylation, the provision of N-acetylcysteine or AdoMet, or experimental approaches such as liver transplantation or enzyme replacement therapy. In several disorders, patients are exposed to long-term markedly elevated Met concentrations. Although these conditions may inform on Met toxicity, interpretation is difficult due to the presence of additional metabolic changes. Two disorders seem to exhibit Met-associated toxicity in the brain. An increased risk of demyelination in patients with Met adenosyltransferase I/III (MATI/III) deficiency due to biallelic mutations in the MATIA gene has been attributed to very high blood Met concentrations (typically >800 μmol/L) and possibly also to decreased liver AdoMet synthesis. An excessively high Met concentration in some patients with cystathionine β-synthase deficiency has been associated with encephalopathy and brain edema, and direct toxicity of Met has been postulated. In summary, studies in patients with various disorders of SAA metabolism showed complex metabolic changes with distant cellular consequences, most of which are not attributable to direct Met toxicity.
Collapse
Affiliation(s)
- Viktor Kožich
- Department of Pediatrics and Adolescent Medicine, Charles University-First Faculty of Medicine and General University Hospital, Prague, Czech Republic
| | - Sally Stabler
- Department of Medicine, University of Colorado School of Medicine Anschutz Medical Campus, Aurora, CO, USA
| |
Collapse
|
7
|
Bannick A, Chase S, Miner A, Seeterlin M, Conway RL. Methionine adenosyltransferase I/III deficiency: Long-term follow-up and treatment of 3 adult siblings. Eur J Med Genet 2020; 63:104076. [PMID: 32980525 DOI: 10.1016/j.ejmg.2020.104076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 08/14/2020] [Accepted: 09/20/2020] [Indexed: 11/17/2022]
Abstract
Methionine adenosyltransferase I/III deficiency, also known as Mudd's disease, is a rare inborn error of methionine metabolism. Because pathophysiological mechanisms of the disease remain poorly understood, the consequences of this disorder and the need for medical management remain uncertain; likewise, the effect of medical interventions on clinical outcomes in Mudd's disease is largely unknown due to a relative lack of published longitudinal clinical data. There are few reports of adults in the medical literature affected with this disease. Clinical symptoms of reported adults range from asymptomatic to individuals with neurological, developmental, or behavioral symptoms. Here we report three siblings affected with Mudd's disease that were ascertained following an abnormal newborn screen for hypermethioninemia in the case of our index patient. All three had a variable degree of longstanding neurologic or psychiatric symptoms which had not prompted a clinical investigation for a genetic or metabolic disorder prior to identification through our clinic. While the causal association of these symptoms to the metabolic disorder remains unclear in these cases, all three patients demonstrated a degree of amelioration of symptoms and/or improvement in measurements on standardized psychiatric ratings scales when specific therapy for the metabolic disorder was instituted. The symptoms, treatment, and outcomes over the course of six years of follow-up are presented here, expanding the possible natural history of Mudd's disease.
Collapse
Affiliation(s)
- Allison Bannick
- Division of Genetic, Genomic and Metabolic Disorders, Children's Hospital of Michigan, Detroit, MI, United States.
| | - Sara Chase
- Wayne State University School of Medicine, Detroit, MI, United States
| | - Alyson Miner
- Division of Genetic, Genomic and Metabolic Disorders, Children's Hospital of Michigan, Detroit, MI, United States
| | - Mary Seeterlin
- Michigan Department of Health and Human Services, Lansing, MI, United States
| | - Robert L Conway
- Division of Genetic, Genomic and Metabolic Disorders, Children's Hospital of Michigan, Detroit, MI, United States; Wayne State University School of Medicine, Detroit, MI, United States
| |
Collapse
|
8
|
Panmanee J, Antonyuk SV, Hasnain SS. Structural basis of the dominant inheritance of hypermethioninemia associated with the Arg264His mutation in the MAT1A gene. Acta Crystallogr D Struct Biol 2020; 76:594-607. [PMID: 32496220 PMCID: PMC7271947 DOI: 10.1107/s2059798320006002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 05/01/2020] [Indexed: 02/06/2023] Open
Abstract
Methionine adenosyltransferase (MAT) deficiency, characterized by isolated persistent hypermethioninemia (IPH), is caused by mutations in the MAT1A gene encoding MATαl, one of the major hepatic enzymes. Most of the associated hypermethioninemic conditions are inherited as autosomal recessive traits; however, dominant inheritance of hypermethioninemia is caused by an Arg264His (R264H) mutation. This mutation has been confirmed in a screening programme of newborns as the most common mutation in babies with IPH. Arg264 makes an inter-subunit salt bridge located at the dimer interface where the active site assembles. Here, it is demonstrated that the R264H mutation results in greatly reduced MAT activity, while retaining its ability to dimerize, indicating that the lower activity arises from alteration at the active site. The first crystallographic structure of the apo form of the wild-type MATαl enzyme is provided, which shows a tetrameric assembly in which two compact dimers combine to form a catalytic tetramer. In contrast, the crystal structure of the MATαl R264H mutant reveals a weaker dimeric assembly, suggesting that the mutation lowers the affinity for dimer-dimer interaction. The formation of a hetero-oligomer with the regulatory MATβV1 subunit or incubation with a quinolone-based compound (SCR0911) results in the near-full recovery of the enzymatic activity of the pathogenic mutation R264H, opening a clear avenue for a therapeutic solution based on chemical interventions that help to correct the defect of the enzyme in its ability to metabolize methionine.
Collapse
Affiliation(s)
- Jiraporn Panmanee
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, United Kingdom
| | - Svetlana V. Antonyuk
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, United Kingdom
| | - S. Samar Hasnain
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, United Kingdom
| |
Collapse
|
9
|
Wang Z, Neupane A, Vo R, White J, Wang X, Marzano SYL. Comparing Gut Microbiome in Mothers' Own Breast Milk- and Formula-Fed Moderate-Late Preterm Infants. Front Microbiol 2020; 11:891. [PMID: 32528425 PMCID: PMC7264382 DOI: 10.3389/fmicb.2020.00891] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 04/16/2020] [Indexed: 12/26/2022] Open
Abstract
Gut microbiome plays an important role in adult human health and diseases. However, how nutritional factors shape the initial colonization of gut bacteria in infants, especially in preterm infants, is still not completely known. In this study, we compared the effects of feeding with mothers' own breast milk (MBM) and formula on the initial composition and gene expression of gut bacteria in moderate-late preterm infants. Fecal samples were collected from ten formula-fed and ten MBM healthy infants born between 32 and 37 weeks' gestation after they reached full-volume enteral feedings. Total DNAs were extracted from fecal samples for amplicon sequencing of 16S ribosomal RNA (rRNA) gene and total RNA with rRNA depletion for metatranscriptome RNA-Seq 16S rRNA gene amplicon sequencing results showed that the alpha-diversity was similar between the MBM- and formula-fed preterm infants, but the beta-diversity showed a significant difference in composition (p = 0.002). The most abundant taxa were Veillonella (18.4%) and Escherichia/Shigella (15.2%) in MBM infants, whereas the most abundant taxa of formula-fed infants were Streptococcus (18.6%) and Klebsiella (17.4%). The genera Propionibacterium, Streptococcus, and Finegoldia and order Clostridiales had significantly higher relative abundance in the MBM group than the formula group, whereas bacteria under family Enterobacteriaceae, genera Enterococcus and Veillonella, and class Bacilli were more abundant in the formula group. In general, microbiomes from both diet groups exhibited high functional levels of catalytic activity and metabolic processing when analyzed for gene ontology using a comparative metatranscriptome approach. Statistically, the microbial genes in the MBM group had an upregulation in expression related to glycine reductase, periplasmic acid stress response in Enterobacteria, acid resistance mechanisms, and L-fucose utilization. In contrast, the formula-fed group had upregulations in genes associated with methionine and valine degradation functions. Our data suggest that the nutritional source plays a role in shaping the moderate-late preterm gut microbiome as evidenced by the differences in bacterial composition and gene expression profiles in the fecal samples. The MBM group enriched Propionibacterium. Glycine reductase was highly upregulated in the microbiota from MBM along with the upregulated acid stress tolerance genes, suggesting that the intensity of fermentation process was enhanced.
Collapse
Affiliation(s)
- Ziyi Wang
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, United States
| | - Achal Neupane
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, United States
| | - Richard Vo
- Department of Pediatrics, Sanford Children’s Hospital, Sanford USD Medical Center, Sioux Falls, SD, United States
- Sanford School of Medicine, University of South Dakota, Vermillion, SD, United States
| | - Jessica White
- Department of Pediatrics, Sanford Children’s Hospital, Sanford USD Medical Center, Sioux Falls, SD, United States
- Sanford School of Medicine, University of South Dakota, Vermillion, SD, United States
| | - Xiuqing Wang
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, United States
| | - Shin-Yi Lee Marzano
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, United States
- Department of Agronomy, Horticulture, and Plant Science, South Dakota State University, Brookings, SD, United States
| |
Collapse
|
10
|
Mogilnicka I, Bogucki P, Ufnal M. Microbiota and Malodor-Etiology and Management. Int J Mol Sci 2020; 21:E2886. [PMID: 32326126 DOI: 10.3390/ijms21082886] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/14/2020] [Accepted: 04/15/2020] [Indexed: 02/06/2023] Open
Abstract
Accumulating evidence indicates that microbiota plays a critical role in physiological processes in humans. However, it might also contribute to body malodor by producing numerous odorous molecules such as ammonia, volatile sulfur compounds or trimethylamine. Although malodor is commonly overlooked by physicians, it constitutes a major problem for many otherwise healthy people. Thus, this review aims to investigate most common causes of malodor and describe potential therapeutic options. We searched PUBMED and Google Scholar databases to identify the clinical and pre-clinical studies on bad body smell, malodor, halitosis and microbiota. Unpleasant smell might originate from the mouth, skin, urine or reproductive fluids and is usually caused by odorants that are produced by resident bacterial flora. The accumulation of odorous compounds might result from diet, specific composition of microbiota, as well as compromised function of the liver, intestines and kidneys. Evidence-based guidelines for management of body malodor are lacking and no universal treatment exists. However, the alleviation of the symptoms may be achieved by controlling the diet and physical elimination of bacteria and/or accumulated odorants.
Collapse
|
11
|
Al-Sadeq DW, Nasrallah GK. The Spectrum of Mutations of Homocystinuria in the MENA Region. Genes (Basel) 2020; 11:genes11030330. [PMID: 32245022 PMCID: PMC7140887 DOI: 10.3390/genes11030330] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/09/2020] [Accepted: 03/13/2020] [Indexed: 12/18/2022] Open
Abstract
Homocystinuria is an inborn error of metabolism due to the deficiency in cystathionine beta-synthase (CBS) enzyme activity. It leads to the elevation of both homocysteine and methionine levels in the blood and urine. Consequently, this build-up could lead to several complications such as nearsightedness, dislocated eye lenses, a variety of psychiatric and behavioral disorders, as well as vascular system complications. The prevalence of homocystinuria is around 1/200,000 births worldwide. However, its prevalence in the Gulf region, notably Qatar, is exceptionally high and reached 1:1800. To date, more than 191 pathogenic CBS mutations have been documented. The majority of these mutations were identified in Caucasians of European ancestry, whereas only a few mutations from African-Americans or Asians were reported. Approximately 87% of all CBS mutations are missense and do not target the CBS catalytic site, but rather result in unstable misfolded proteins lacking the normal biological function, designating them for degradation. The early detection of homocystinuria along with low protein and methionine-restricted diet is the best treatment approach for all types of homocystinuria patients. Yet, less than 50% of affected individuals show a significant reduction in plasma homocysteine levels after treatment. Patients who fail to lower the elevated homocysteine levels, through high protein-restricted diet or by B6 and folic acid supplements, are at higher risk for cardiovascular diseases, neurodegenerative diseases, neural tube defects, and other severe clinical complications. This review aims to examine the mutations spectrum of the CBS gene, the disease management, as well as the current and potential treatment approaches with a greater emphasis on studies reported in the Middle East and North Africa (MENA) region.
Collapse
Affiliation(s)
- Duaa W. Al-Sadeq
- Biomedical Research Center, Qatar University, P.O. Box 2713 Doha, Qatar
- College of Medicine, Member of QU Health, Qatar University, P.O. Box 2713 Doha, Qatar
- Correspondence: (G.K.N.); (D.W.A-S.); Tel.: +974-4403-6623 (D.W.A-S.); +974-4403-4817 (G.K.N.); Fax: +974-4403-1351 (G.K.N.)
| | - Gheyath K. Nasrallah
- Biomedical Research Center, Qatar University, P.O. Box 2713 Doha, Qatar
- Department of Biomedical Science, College of Health Sciences, Qatar University, P.O. Box 2713 Doha, Qatar
- Correspondence: (G.K.N.); (D.W.A-S.); Tel.: +974-4403-6623 (D.W.A-S.); +974-4403-4817 (G.K.N.); Fax: +974-4403-1351 (G.K.N.)
| |
Collapse
|
12
|
Zhang Z, Wang Y, Ma D, Cheng W, Sun Y, Jiang T. Analysis of five cases of hypermethioninemia diagnosed by neonatal screening. J Pediatr Endocrinol Metab 2020; 33:47-52. [PMID: 31851615 DOI: 10.1515/jpem-2019-0285] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 10/14/2019] [Indexed: 11/15/2022]
Abstract
Background Hypermethioninemia is a group of diseases with elevated plasma methionine (Met) caused by hereditary and non-hereditary factors, although it could also be caused by administration of the amino acid Met. Among these, the disease caused by methionine adenosyltransferase (MAT) I/III deficiency is the most common, and is characterized by persistent, isolated hypermethioninemia as well as slightly elevated homocysteine. S-adenosylmethionine is the product of Met, which can be used as a direct methyl donor of many substances, such as choline and nucleotide, and essential in the development of the body. Among the patients, most have no symptoms, and a small number have central nervous system complications with high levels of plasma Met, including mental retardation, cognitive impairment and special breathing odor. Methods In this study, five cases of MAT I/III deficiency were diagnosed and retrospectively analyzed among 220,000 newborns. Patients with high Met levels received a Met-restricted diet treatment. Results and conclusions MAT I/III deficiency is a common reason for Met elevation in neonatal screening by tandem mass spectrometry (MS/MS), which needs long-term follow-up except for these patients with explicitly benign mutations.
Collapse
Affiliation(s)
- Zhilei Zhang
- Center of Genetic Medicine, The Affiliated Obstetrics and Gynecology Hospital with Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, China
| | - Yanyun Wang
- Center of Genetic Medicine, The Affiliated Obstetrics and Gynecology Hospital with Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, China
| | - Dingyuan Ma
- Center of Genetic Medicine, The Affiliated Obstetrics and Gynecology Hospital with Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, China
| | - Wei Cheng
- Center of Genetic Medicine, The Affiliated Obstetrics and Gynecology Hospital with Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, China
| | - Yun Sun
- Center of Genetic Medicine, The Affiliated Obstetrics and Gynecology Hospital with Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, China
| | - Tao Jiang
- Center of Genetic Medicine, The Affiliated Obstetrics and Gynecology Hospital with Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, China
| |
Collapse
|
13
|
Abstract
Metabolic dysregulation is an appreciated hallmark of cancer and a target for therapeutic intervention. Cellular metabolism involves a series of oxidation/reduction (redox) reactions that yield the energy and biomass required for tumor growth. Cells require diverse molecular species with constituent sulfur atoms to facilitate these processes. For humans, this sulfur is derived from the dietary consumption of the proteinogenic amino acids cysteine and methionine, as only lower organisms (e.g., bacteria, fungi, and plants) can synthesize them de novo. In addition to providing the sulfur required to sustain redox chemistry, the metabolism of these sulfur-containing amino acids yield intermediate metabolites that constitute the cellular antioxidant system, mediate inter- and intracellular signaling, and facilitate the epigenetic regulation of gene expression, all of which contribute to tumorigenesis.
Collapse
Affiliation(s)
- Nathan P Ward
- Department of Cancer Physiology, Moffitt Cancer Center and Research Institute, Tampa, FL, United States
| | - Gina M DeNicola
- Department of Cancer Physiology, Moffitt Cancer Center and Research Institute, Tampa, FL, United States.
| |
Collapse
|
14
|
Panmanee J, Bradley-Clarke J, Mato JM, O'Neill PM, Antonyuk SV, Hasnain SS. Control and regulation of S-Adenosylmethionine biosynthesis by the regulatory β subunit and quinolone-based compounds. FEBS J 2019; 286:2135-2154. [PMID: 30776190 PMCID: PMC6850014 DOI: 10.1111/febs.14790] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 01/17/2019] [Accepted: 02/15/2019] [Indexed: 12/13/2022]
Abstract
Methylation is an underpinning process of life and provides control for biological processes such as DNA synthesis, cell growth, and apoptosis. Methionine adenosyltransferases (MAT) produce the cellular methyl donor, S‐Adenosylmethionine (SAMe). Dysregulation of SAMe level is a relevant event in many diseases, including cancers such as hepatocellular carcinoma and colon cancer. In addition, mutation of Arg264 in MATα1 causes isolated persistent hypermethioninemia, which is characterized by low activity of the enzyme in liver and high level of plasma methionine. In mammals, MATα1/α2 and MATβV1/V2 are the catalytic and the major form of regulatory subunits, respectively. A gating loop comprising residues 113–131 is located beside the active site of catalytic subunits (MATα1/α2) and provides controlled access to the active site. Here, we provide evidence of how the gating loop facilitates the catalysis and define some of the key elements that control the catalytic efficiency. Mutation of several residues of MATα2 including Gln113, Ser114, and Arg264 lead to partial or total loss of enzymatic activity, demonstrating their critical role in catalysis. The enzymatic activity of the mutated enzymes is restored to varying degrees upon complex formation with MATβV1 or MATβV2, endorsing its role as an allosteric regulator of MATα2 in response to the levels of methionine or SAMe. Finally, the protein–protein interacting surface formed in MATα2:MATβ complexes is explored to demonstrate that several quinolone‐based compounds modulate the activity of MATα2 and its mutants, providing a rational for chemical design/intervention responsive to the level of SAMe in the cellular environment. Enzymes Methionine adenosyltransferase (http://www.chem.qmul.ac.uk/iubmb/enzyme/EC2/5/1/6.html). Database Structural data are available in the RCSB PDB database under the PDB ID http://www.rcsb.org/pdb/search/structidSearch.do?structureId=6FBN (Q113A), http://www.rcsb.org/pdb/search/structidSearch.do?structureId=6FBP (S114A: P22121), http://www.rcsb.org/pdb/search/structidSearch.do?structureId=6FBO (S114A: I222), http://www.rcsb.org/pdb/search/structidSearch.do?structureId=6FCB (P115G), http://www.rcsb.org/pdb/search/structidSearch.do?structureId=6FCD (R264A), http://www.rcsb.org/pdb/search/structidSearch.do?structureId=6FAJ (wtMATα2: apo), http://www.rcsb.org/pdb/search/structidSearch.do?structureId=6G6R (wtMATα2: holo)
Collapse
Affiliation(s)
- Jiraporn Panmanee
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, UK
| | - Jack Bradley-Clarke
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, UK
| | - Jose M Mato
- Metabolomics Unit, CIC bioGUNE, CIBERehd, Parque Tecnologico de Bizkaia, Derio, Spain
| | - Paul M O'Neill
- Department of Chemistry, School of Physical Sciences, University of Liverpool, UK
| | - Svetlana V Antonyuk
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, UK
| | - S Samar Hasnain
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, UK
| |
Collapse
|
15
|
Hayashi T, Teruya T, Chaleckis R, Morigasaki S, Yanagida M. S-Adenosylmethionine Synthetase Is Required for Cell Growth, Maintenance of G0 Phase, and Termination of Quiescence in Fission Yeast. iScience 2018; 5:38-51. [PMID: 30240645 PMCID: PMC6123894 DOI: 10.1016/j.isci.2018.06.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 06/04/2018] [Accepted: 06/27/2018] [Indexed: 01/04/2023] Open
Abstract
S-adenosylmethionine is an important compound, because it serves as the methyl donor in most methyl transfer reactions, including methylation of proteins, nucleic acids, and lipids. However, cellular defects in the genetic disruption of S-adenosylmethionine synthesis are not well understood. Here, we report the isolation and characterization of temperature-sensitive mutants of fission yeast S-adenosylmethionine synthetase (Sam1). Levels of S-adenosylmethionine and methylated histone H3 were greatly diminished in sam1 mutants. sam1 mutants stopped proliferating in vegetative culture and arrested specifically in G2 phase without cell elongation. Furthermore, sam1 mutants lost viability during nitrogen starvation-induced G0 phase quiescence. After release from the G0 state, sam1 mutants could neither increase in cell size nor re-initiate DNA replication in the rich medium. Sam1 is thus required for cell growth and proliferation, and maintenance of and exit from quiescence. sam1 mutants lead to broad cellular and drug response defects, as expected, since S. pombe contains more than 90 S-adenosylmethionine-dependent methyltransferases.
Collapse
Affiliation(s)
- Takeshi Hayashi
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Takayuki Teruya
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Romanas Chaleckis
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Susumu Morigasaki
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - Mitsuhiro Yanagida
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan.
| |
Collapse
|
16
|
Ishida M, Cullup T, Boustred C, James C, Docker J, English C, Lench N, Copp AJ, Moore GE, Greene NDE, Stanier P. A targeted sequencing panel identifies rare damaging variants in multiple genes in the cranial neural tube defect, anencephaly. Clin Genet 2018; 93:870-879. [PMID: 29205322 PMCID: PMC5887939 DOI: 10.1111/cge.13189] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/26/2017] [Accepted: 11/27/2017] [Indexed: 12/12/2022]
Abstract
Neural tube defects (NTDs) affecting the brain (anencephaly) are lethal before or at birth, whereas lower spinal defects (spina bifida) may lead to lifelong neurological handicap. Collectively, NTDs rank among the most common birth defects worldwide. This study focuses on anencephaly, which despite having a similar frequency to spina bifida and being the most common type of NTD observed in mouse models, has had more limited inclusion in genetic studies. A genetic influence is strongly implicated in determining risk of NTDs and a molecular diagnosis is of fundamental importance to families both in terms of understanding the origin of the condition and for managing future pregnancies. Here we used a custom panel of 191 NTD candidate genes to screen 90 patients with cranial NTDs (n = 85 anencephaly and n = 5 craniorachischisis) with a targeted exome sequencing platform. After filtering and comparing to our in‐house control exome database (N = 509), we identified 397 rare variants (minor allele frequency, MAF < 1%), 21 of which were previously unreported and predicted damaging. This included 1 frameshift (PDGFRA), 2 stop‐gained (MAT1A; NOS2) and 18 missense variations. Together with evidence for oligogenic inheritance, this study provides new information on the possible genetic causation of anencephaly.
Collapse
Affiliation(s)
- M Ishida
- Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - T Cullup
- Great Ormond Street Hospital North East Thames Regional Genetics Service Laboratories, London, UK
| | - C Boustred
- Great Ormond Street Hospital North East Thames Regional Genetics Service Laboratories, London, UK
| | - C James
- Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - J Docker
- Great Ormond Street Hospital North East Thames Regional Genetics Service Laboratories, London, UK
| | - C English
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | -
- Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - N Lench
- Great Ormond Street Hospital North East Thames Regional Genetics Service Laboratories, London, UK.,Congenica Ltd, Cambridge, UK
| | - A J Copp
- Developmental Biology and Cancer, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - G E Moore
- Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - N D E Greene
- Developmental Biology and Cancer, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - P Stanier
- Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| |
Collapse
|
17
|
Abstract
Methionine adenosyltransferase (MAT) I/III deficiency (OMIM # 250850) is caused by a mutation in MAT1A, which encodes the two hepatic MAT isozymes I and III. With the implementation of newborn screening program to discover hypermethioninemia due to cystathionine beta-synthase deficiency, more cases are being discovered. While the majority of patients are asymptomatic, some might have central nervous system (CNS) and extra-CNS manifestations. Although neurologic manifestations and demyelination have been correlated to MAT deficiency in many reported cases, none of the previous reports focused on extra-CNS manifestations associated with the disease. This is a retrospective chart review for a 40-month-old patient with confirmed diagnosis of MAT deficiency. He was found to have a novel homozygous disease-causing variant in MAT1A (NM_000429.2) c.1081G>T (p.Val361Phe). Interestingly, our patient had an unexplained zinc and iron deficiency in addition to mild speech delay. We reviewed the literature and summarized all the reported extra-CNS manifestations. In conclusion, MAT deficiency patients should be thoroughly investigated to check for CNS and extra-CNS manifestations associated with the disease. Keeping in consideration the challenge of assuming correlation, a scrutinized look at extra-CNS manifestations and their course with time might pave the way to understanding the pathophysiology of the disease and MAT1A function.
Collapse
Affiliation(s)
- Marwan Nashabat
- King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Sciences, Division of Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Sultan Al-Khenaizan
- Department of Dermatology, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Majid Alfadhel
- King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Sciences, Division of Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia
| |
Collapse
|
18
|
Abstract
Homocystinuria is an inherited metabolic disorder most commonly caused by cystathionine β-synthase deficiency. Severe cases can cause white matter abnormalities that can mimic other vascular, toxic and metabolic disorders on computed tomography and magnetic resonance imaging. We present such a case which demonstrates not only extensive white matter abnormalities on magnetic resonance imaging, but also previously unreported basal ganglia signal abnormalities and imaging manifestations of increased intracranial pressure, likely caused by elevated methionine and betaine therapy. We also review the literature and discuss the potential underlying biologic mechanisms of these imaging findings.
Collapse
Affiliation(s)
- Charles Q Li
- Department of Radiology, University of California, San Diego, San Diego, USA
| | - Bruce A Barshop
- Department of Pediatrics, University of California, San Diego, La Jolla, USA
| | - Annette Feigenbaum
- Department of Pediatrics, University of California, San Diego, La Jolla, USA
| | - Paritosh C Khanna
- Department of Radiology, Rady Children's Hospital-San Diego, San Diego, USA
| |
Collapse
|
19
|
Abstract
Methionine adenosyltransferases (MATs) are essential for cell survival because they catalyze the biosynthesis of the biological methyl donor S-adenosylmethionine (SAMe) from methionine and adenosine triphosphate (ATP). Mammalian cells express two genes, MAT1A and MAT2A, which encode two MAT catalytic subunits, α1 and α2, respectively. The α1 subunit organizes into dimers (MATIII) or tetramers (MATI). The α2 subunit is found in the MATII isoform. A third gene MAT2B, encodes a regulatory subunit β, that regulates the activity of MATII by lowering the inhibition constant (Ki) for SAMe and the Michaelis constant (Km) for methionine. MAT1A expressed mainly in hepatocytes maintains the differentiated state of these cells whereas MAT2A and MAT2B are expressed in non-parenchymal cells of the liver (hepatic stellate cells [HSCs] and Kupffer cells) and extrahepatic tissues. A switch from the liver-specific MAT1A to MAT2A has been observed during conditions of active liver growth and de-differentiation. Liver injury, fibrosis, and cancer are associated with MAT1A silencing and MAT2A/MAT2B induction. Even though both MAT1A and MAT2A are involved in SAMe biosynthesis, they exhibit distinct molecular interactions in liver cells. This review provides an update on MAT genes and their roles in liver pathologies.
Collapse
Affiliation(s)
- Komal Ramani
- Corresponding authors: Division of Digestive and Liver
Diseases, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA,
USA (K.Ramani)
| | | |
Collapse
|
20
|
Barić I, Staufner C, Augoustides-Savvopoulou P, Chien YH, Dobbelaere D, Grünert SC, Opladen T, Petković Ramadža D, Rakić B, Wedell A, Blom HJ. Consensus recommendations for the diagnosis, treatment and follow-up of inherited methylation disorders. J Inherit Metab Dis 2017; 40:5-20. [PMID: 27671891 PMCID: PMC5203850 DOI: 10.1007/s10545-016-9972-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/25/2016] [Accepted: 07/27/2016] [Indexed: 12/24/2022]
Abstract
Inherited methylation disorders are a group of rarely reported, probably largely underdiagnosed disorders affecting transmethylation processes in the metabolic pathway between methionine and homocysteine. These are methionine adenosyltransferase I/III, glycine N-methyltransferase, S-adenosylhomocysteine hydrolase and adenosine kinase deficiencies. This paper provides the first consensus recommendations for the diagnosis and management of methylation disorders. Following search of the literature and evaluation according to the SIGN-methodology of all reported patients with methylation defects, graded recommendations are provided in a structured way comprising diagnosis (clinical presentation, biochemical abnormalities, differential diagnosis, newborn screening, prenatal diagnosis), therapy and follow-up. Methylation disorders predominantly affect the liver, central nervous system and muscles, but clinical presentation can vary considerably between and within disorders. Although isolated hypermethioninemia is the biochemical hallmark of this group of disorders, it is not always present, especially in early infancy. Plasma S-adenosylmethionine and S-adenosylhomocysteine are key metabolites for the biochemical clarification of isolated hypermethioninemia. Mild hyperhomocysteinemia can be present in all methylation disorders. Methylation disorders do not qualify as primary targets of newborn screening. A low-methionine diet can be beneficial in patients with methionine adenosyltransferase I/III deficiency if plasma methionine concentrations exceed 800 μmol/L. There is some evidence that this diet may also be beneficial in patients with S-adenosylhomocysteine hydrolase and adenosine kinase deficiencies. S-adenosylmethionine supplementation may be useful in patients with methionine adenosyltransferase I/III deficiency. Recommendations given in this article are based on general principles and in practice should be adjusted individually according to patient's age, severity of the disease, clinical and laboratory findings.
Collapse
Affiliation(s)
- Ivo Barić
- Department of Pediatrics, University Hospital Center Zagreb, Kišpatićeva 12, Rebro, 10000, Zagreb, Croatia.
- University of Zagreb, School of Medicine, Zagreb, Croatia.
| | - Christian Staufner
- Department of General Pediatrics, Division of Metabolic Medicine and Neuropediatrics, University Hospital Heidelberg, 69120, Heidelberg, Germany
| | | | - Yin-Hsiu Chien
- Department of Medical Genetics and Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | - Dries Dobbelaere
- Medical Reference Center for Inherited Metabolic Diseases, Jeanne de Flandre University Hospital and RADEME Research Team for Rare Metabolic and Developmental Diseases, EA 7364 CHRU Lille, 59037, Lille, France
| | | | - Thomas Opladen
- Department of General Pediatrics, Division of Metabolic Medicine and Neuropediatrics, University Hospital Heidelberg, 69120, Heidelberg, Germany
| | - Danijela Petković Ramadža
- Department of Pediatrics, University Hospital Center Zagreb, Kišpatićeva 12, Rebro, 10000, Zagreb, Croatia
| | - Bojana Rakić
- Biochemical Genetics Laboratory, BC Children's Hospital, 4500 Oak Street, Vancouver, BC, V6H 3N1, Canada
| | - Anna Wedell
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Henk J Blom
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics Adolescent Medicine and Neonatology, University Medical Centre Freiburg, Freiburg, Germany
| |
Collapse
|
21
|
Kim YM, Kim JH, Choi J, Gu-Hwan K, Kim JM, Kang M, Choi IH, Cheon CK, Sohn YB, Maccarana M, Yoo HW, Lee BH. Determination of Autosomal Dominant or Recessive Methionine Adenosyltransferase I/III Deficiencies Based on Clinical and Molecular Studies. Mol Med 2016; 22:147-155. [PMID: 26933843 DOI: 10.2119/molmed.2015.00254] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/09/2016] [Indexed: 11/06/2022] Open
Abstract
Methionine adenosyltransferase (MAT) I/III deficiency can be inherited as autosomal dominant (AD) or as recessive (AR) traits in which mono- or biallelic MAT1A mutations have been identified, respectively. Although most patients have benign clinical outcomes, some with the AR form have neurological deficits. Here we describe 16 Korean patients with MAT I/III deficiency from 15 unrelated families identified by newborn screening. Ten probands had the AD MAT I/III deficiency, while six had AR MAT I/III deficiency. Plasma methionine (145.7 μmol/L versus 733.2 μmol/L, P < 0.05) and homocysteine levels (12.3 μmol/L versus 18.6 μmol/L, P < 0.05) were lower in the AD type than in AR type. In addition to the only reported AD MAT1A mutation, p.Arg264His, we identified two novel AD mutations, p.Arg249Gln and p.Gly280Arg. In the AR type, four previously reported and two novel mutations, p.Arg163Trp and p.Tyr335*, were identified. No exonic deletions were found by quantitative genomic polymerase chain reaction (PCR). Three-dimensional structural prediction programs indicated that the AD-type mutations were located on the dimer interface or in the substrate binding site, hindering MAT I/III dimerization or substrate binding, respectively, whereas the AR mutations were distant from the interface or substrate binding site. These results indicate that the AD or AR MAT I/III deficiency is correlated with clinical findings, substrate levels and structural features of the mutant proteins, which is important for the neurological management and genetic counseling of the patients.
Collapse
Affiliation(s)
- Yoo-Mi Kim
- Department of Pediatrics, College of Medicine, Pusan National University Children's Hospital, Yangsan, Korea
| | - Ja Hye Kim
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Jin Choi
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Kim Gu-Hwan
- Medical Genetics Center, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Jae-Min Kim
- Medical Genetics Center, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Minji Kang
- Medical Genetics Center, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - In-Hee Choi
- Medical Genetics Center, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Chong Kun Cheon
- Department of Pediatrics, College of Medicine, Pusan National University Children's Hospital, Yangsan, Korea
| | - Young Bae Sohn
- Department of Medical Genetics, Ajou University Hospital, Ajou University School of Medicine, Suwon, Korea
| | - Marco Maccarana
- Department of Experimental Medical Science, BMC, Lund University, Sweden
| | - Han-Wook Yoo
- Medical Genetics Center, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Beom Hee Lee
- Medical Genetics Center, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| |
Collapse
|
22
|
Gong B, Liu L, Li Z, Ye Z, Xiao Y, Zeng G, Shi Y, Wang Y, Feng X, Li X, Hao F, Liu X, Qu C, Li Y, Mu G, Yang Z. Novel Compound Heterozygous CBS Mutations Cause Homocystinuria in a Han Chinese Family. Sci Rep 2015; 5:17947. [PMID: 26667307 PMCID: PMC4678370 DOI: 10.1038/srep17947] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 11/09/2015] [Indexed: 11/09/2022] Open
Abstract
The cystathionine β-synthase (CBS) gene has been shown to be related to homocystinuria. This study was aimed to detect the mutations in CBS in a Han Chinese family with homocystinuria. A four-generation family from Shandong Province of China was recruited in this study. All available members of the family underwent comprehensive medical examinations. Genomic DNA was collected from peripheral blood of all the participants. The coding sequence of CBS was amplified by polymerase chain reaction (PCR), followed by direct DNA sequencing. Among all the family members, three affected individuals showed typical clinical features of homocystinuria. Two novel compound heterozygous mutations in the CBS gene, c.407T > C (p. L136P) and c.473C > T (p.A158V), were identified by sequencing analysis in this family. Both of the two missense mutations were detected in the three patients. Other available normal individuals, including the patients' parents, grand parents, her younger sister and brother in this family either carried one of the two mutations, or none. In addition, the two mutations were not found in 600 ethnically matched normal controls. This study provides a mutation spectrum of CBS resulting in homocystinuriain a Chinese population, which may shed light on the molecular pathogenesis and clinical diagnosis of CBS-associated homocystinuria.
Collapse
Affiliation(s)
- Bo Gong
- Sichuan Provincial Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Liping Liu
- Department of Ophthalmology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - Zhiwei Li
- Department of Ophthalmology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - Zimeng Ye
- Sichuan Provincial Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Ying Xiao
- Department of Ophthalmology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - Guangqun Zeng
- Sichuan Provincial Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Yi Shi
- Sichuan Provincial Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Yumeng Wang
- Department of Ophthalmology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - Xiaoyun Feng
- Sichuan Provincial Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Xiulan Li
- Sichuan Provincial Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Fang Hao
- Sichuan Provincial Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Xiaoqi Liu
- Sichuan Provincial Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Chao Qu
- Department of Ophthalmology, School of Medicine, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Yuanfeng Li
- Sichuan Provincial Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Guoying Mu
- Department of Ophthalmology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - Zhenglin Yang
- Sichuan Provincial Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| |
Collapse
|
23
|
Chien YH, Abdenur JE, Baronio F, Bannick AA, Corrales F, Couce M, Donner MG, Ficicioglu C, Freehauf C, Frithiof D, Gotway G, Hirabayashi K, Hofstede F, Hoganson G, Hwu WL, James P, Kim S, Korman SH, Lachmann R, Levy H, Lindner M, Lykopoulou L, Mayatepek E, Muntau A, Okano Y, Raymond K, Rubio-Gozalbo E, Scholl-Bürgi S, Schulze A, Singh R, Stabler S, Stuy M, Thomas J, Wagner C, Wilson WG, Wortmann S, Yamamoto S, Pao M, Blom HJ. Mudd's disease (MAT I/III deficiency): a survey of data for MAT1A homozygotes and compound heterozygotes. Orphanet J Rare Dis 2015; 10:99. [PMID: 26289392 PMCID: PMC4545930 DOI: 10.1186/s13023-015-0321-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 08/13/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND This paper summarizes the results of a group effort to bring together the worldwide available data on patients who are either homozygotes or compound heterozygotes for mutations in MAT1A. MAT1A encodes the subunit that forms two methionine adenosyltransferase isoenzymes, tetrameric MAT I and dimeric MAT III, that catalyze the conversion of methionine and ATP to S-adenosylmethionine (AdoMet). Subnormal MAT I/III activity leads to hypermethioninemia. Individuals, with hypermethioninemia due to one of the MAT1A mutations that in heterozygotes cause relatively mild and clinically benign hypermethioninemia are currently often being flagged in screening programs measuring methionine elevation to identify newborns with defective cystathionine β-synthase activity. Homozygotes or compound heterozygotes for MAT1A mutations are less frequent. Some but not all, such individuals have manifested demyelination or other CNS abnormalities. PURPOSE OF THE STUDY The goals of the present effort have been to determine the frequency of such abnormalities, to find how best to predict whether they will occur, and to evaluate the outcomes of the variety of treatment regimens that have been used. Data have been gathered for 64 patients, of whom 32 have some evidence of CNS abnormalities (based mainly on MRI findings), and 32 do not have such evidence. RESULTS AND DISCUSSION The results show that mean plasma methionine concentrations provide the best indication of the group into which a given patient will fall: those with means of 800 μM or higher usually have evidence of CNS abnormalities, whereas those with lower means usually do not. Data are reported for individual patients for MAT1A genotypes, plasma methionine, total homocysteine (tHcy), and AdoMet concentrations, liver function studies, results of 15 pregnancies, and the outcomes of dietary methionine restriction and/or AdoMet supplementation. Possible pathophysiological mechanisms that might contribute to CNS damage are discussed, and tentative suggestions are put forth as to optimal management.
Collapse
Affiliation(s)
- Yin-Hsiu Chien
- Department of Medical Genetics and Pediatrics, National Taiwan University Hospital, Children's Hospital Building, Taipei, Taiwan
| | - Jose E Abdenur
- Division of Metabolic Disorders, CHOC Children's, Orange, CA, USA
| | - Federico Baronio
- Newborn Screening and Inborn Errors of Metabolism Regional Centre, Pediatric Endocrinology Program, Pediatric Unit, S.Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy
| | - Allison Anne Bannick
- Children's Hospital of Michigan Metabolic Clinic, Detroit Medical Center, Detroit, MI, USA
| | - Fernando Corrales
- Department of Hepatology, Proteomics laboratory, Center for Applied Medical Research (CIMA), University of Navarra, IdiSNA, Pamplona, Spain
| | - Maria Couce
- Head of Metabolic Unit, Department Pediatrics, Hospital Clínico Universitario de Santiago, Santiago de Compostela, Spain
| | - Markus G Donner
- Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Can Ficicioglu
- The Children's Hospital of Philadelphia, Division of Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Cynthia Freehauf
- Department of Pediatrics, University of Colorado, Aurora, CO, USA
| | - Deborah Frithiof
- Department of Clinical Sciences, Pediatrics Umeå University, SE 901 85, Umeå, Sweden
| | - Garrett Gotway
- Department of Pediatrics, Division of Genetics and Metabolism; Department of Internal Medicine, Division of Clinical Genetics; and McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Koichi Hirabayashi
- Department of Pediatrics, Shinshu University School of Medicine, 3-1-1, Asahi, Matsumoto, Japan
| | - Floris Hofstede
- Division of Paediatrics, Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - George Hoganson
- Department of Pediatrics, University of Illinois at Chicago, College of Medicine, Chicago, Il, USA
| | - Wuh-Liang Hwu
- Department of Medical Genetics and Pediatrics, National Taiwan University Hospital, Children's Hospital Building, Taipei, Taiwan
| | - Philip James
- Children's Hospital Boston, Harvard Medical School, Boston, USA
| | - Sook Kim
- KSZ Children's Hospital/Korea Genetics Research Center, Jikjidaero, Heung Duck Gu, Cheng Ju City, Chung Buk, Republic of Korea
| | - Stanley H Korman
- Department of Genetics and Department of Metabolic Diseases, Hebrew University, Hadassah Medical Center, Jerusalem, Israel
| | - Robin Lachmann
- Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, London, UK
| | - Harvey Levy
- Children's Hospital Boston, Harvard Medical School, Boston, USA
| | - Martin Lindner
- Department of General Pediatrics, Division of Pediatric Metabolic Medicine and Neuropediatrics, University Hospital Heidelberg, Heidelberg, Germany
- Department of Neurology, University Children's Hospital Frankfurt, Frankfurt, Germany
| | - Lilia Lykopoulou
- First Department of Pediatrics, University of Athens, Agia Sofia Children's Hospital, Athens, Greece
| | - Ertan Mayatepek
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital Duesseldorf, Duesseldorf, Germany
| | - Ania Muntau
- University Children's Hospital, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Yoshiyuki Okano
- Department of Genetics, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Japan
| | - Kimiyo Raymond
- Department of Medicine and Pathology, Biochemical Genetics Laboratory, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Estela Rubio-Gozalbo
- Department of Pediatrics and Laboratory Genetic Metabolic Diseases, Maastricht University Medical Center, Maastricht, Netherlands
| | - Sabine Scholl-Bürgi
- Medical University of Innsbruck, Clinic for Pediatrics, Inherited Metabolic Disorders, Innsbruck, Austria
| | - Andreas Schulze
- Genetics and Genome Biology, Peter Gilgan Center for Research and Learning The Hospital for Sick Children, Toronto, ON, Canada
| | - Rani Singh
- Department of Human Genetics and Pediatric, Emory University, Atlanta, GA, USA
| | - Sally Stabler
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | - Mary Stuy
- Department of Medical and Molecular Genetics Indiana University School of Medicine, Indianapolis, IN, USA
| | - Janet Thomas
- Department of Pediatrics, University of Colorado, Aurora, CO, USA
| | - Conrad Wagner
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tn, USA
| | - William G Wilson
- Division of Genetics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Saskia Wortmann
- Nijmegen Centre for Mitochondrial Disorders (NCMD), RadboudUMC, Amalia Children's Hospital, Nijmegen, The Netherlands
| | | | - Maryland Pao
- Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD, USA
| | - Henk J Blom
- Laboratory for Clinical Biochemistry and Metabolism, Center for Pediatrics and Adolescent Medicine University Hospital Freiburg, 79106, Freiburg, Germany.
| |
Collapse
|
24
|
Marcão A, Couce ML, Nogueira C, Fonseca H, Ferreira F, Fraga JM, Bóveda MD, Vilarinho L. Newborn Screening for Homocystinuria Revealed a High Frequency of MAT I/III Deficiency in Iberian Peninsula. JIMD Rep 2015; 20:113-20. [PMID: 25638462 DOI: 10.1007/8904_2014_400] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 12/17/2014] [Accepted: 12/18/2014] [Indexed: 01/12/2023] Open
Abstract
Homocystinuria due to cystathionine β-synthase deficiency or "classical homocystinuria" is a rare autosomal recessive condition resulting in altered sulfur metabolism with elevated methionine and homocysteine in plasma and homocystine in urine. This condition is characterized by a high clinical heterogeneity, which contributes to late clinical diagnosis, usually only made after irreversible damage has occurred. Treatment is effective if started before clinical symptoms. The analysis of methionine levels by tandem mass spectrometry (MS/MS) allows the newborn screening for homocystinuria, but false-positive results can be frequently obtained and lead to the unwanted identification of methionine adenosyl transferase (MAT I/III) deficiency. This latter condition is biochemically characterized by isolated persistent hypermethioninemia, accompanied in some individuals with slightly elevated levels of homocysteine in plasma. A dominant form of MAT I/III deficiency, associated with mutation p.R264H, seems to be very frequent in the Iberian Peninsula and usually has a clinically benign course. Both these metabolic disorders are screened in Galicia and Portugal since the introduction of the MS/MS technology, in 2000 and 2004, respectively, resulting in the identification of three patients with classical homocystinuria and 44 patients with MAT I/III deficiency. All but one heterozygous parent of MAT I/III patients, identified with the p.R264H mutation, are healthy adults around the age of 30/40. The implementation of a second-tier test for homocysteine in dried blood spots would considerably reduce the number of MAT I/III-deficient patients identified and improve the specificity and positive predictive value for classical homocystinuria screening.
Collapse
|
25
|
Guo DC, Gong L, Regalado E, Santos-Cortez R, Zhao R, Cai B, Veeraraghavan S, Prakash S, Johnson R, Muilenburg A, Willing M, Jondeau G, Boileau C, Pannu H, Moran R, Debacker J, Bamshad M, Shendure J, Nickerson D, Leal S, Raman C, Swindell E, Milewicz D, Swindell EC, Milewicz DM. MAT2A mutations predispose individuals to thoracic aortic aneurysms. Am J Hum Genet 2015; 96:170-7. [PMID: 25557781 DOI: 10.1016/j.ajhg.2014.11.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 11/30/2014] [Indexed: 02/06/2023] Open
Abstract
Up to 20% of individuals who have thoracic aortic aneurysms or acute aortic dissections but who do not have syndromic features have a family history of thoracic aortic disease. Significant genetic heterogeneity is established for this familial condition. Whole-genome linkage analysis and exome sequencing of distant relatives from a large family with autosomal-dominant inheritance of thoracic aortic aneurysms variably associated with the bicuspid aortic valve was used for identification of additional genes predisposing individuals to this condition. A rare variant, c.1031A>C (p.Glu344Ala), was identified in MAT2A, which encodes methionine adenosyltransferase II alpha (MAT IIα). This variant segregated with disease in the family, and Sanger sequencing of DNA from affected probands from unrelated families with thoracic aortic disease identified another MAT2A rare variant, c.1067G>A (p.Arg356His). Evidence that these variants predispose individuals to thoracic aortic aneurysms and dissections includes the following: there is a paucity of rare variants in MAT2A in the population; amino acids Glu344 and Arg356 are conserved from humans to zebrafish; and substitutions of these amino acids in MAT Iα are found in individuals with hypermethioninemia. Structural analysis suggested that p.Glu344Ala and p.Arg356His disrupt MAT IIα enzyme function. Knockdown of mat2aa in zebrafish via morpholino oligomers disrupted cardiovascular development. Co-transfected wild-type human MAT2A mRNA rescued defects of zebrafish cardiovascular development at significantly higher levels than mRNA edited to express either the Glu344 or Arg356 mutants, providing further evidence that the p.Glu344Ala and p.Arg356His substitutions impair MAT IIα function. The data presented here support the conclusion that rare genetic variants in MAT2A predispose individuals to thoracic aortic disease.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Eric C Swindell
- Department of Pediatrics, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Dianna M Milewicz
- Department of Internal Medicine, University of Texas Health Science Center, Houston, TX 77030, USA.
| |
Collapse
|
26
|
Chadwick S, Fitzgerald K, Weiss B, Ficicioglu C. Thirteen Patients with MAT1A Mutations Detected Through Newborn Screening: 13 Years' Experience. JIMD Rep 2014; 14:71-6. [PMID: 24445979 PMCID: PMC4213332 DOI: 10.1007/8904_2013_286] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 11/22/2013] [Accepted: 12/04/2013] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Methionine adenosyltransferase I/III (MATI/III) deficiency is the most common genetic cause of persistent isolated hypermethioninemia. Patients and Methods : This is a retrospective data analysis of 62 newborns with elevated methionine detected by newborn screening between January 2000 and June 2013. The clinical, biochemical, and molecular findings of a subset of these children with MAT1A mutations associated with MATI/III deficiency are presented. RESULTS Of the 62 newborns with elevated methionine, 12 were identified as having classical homocystinuria; 37 were false-positives; and 13 were found to have isolated persistent hypermethioninemia in the absence of biochemical markers of homocystinuria, abnormal liver function studies, or other causes of elevated methionine. These 13 individuals underwent genetic testing for changes in the MAT1A gene, associated with MATI/III deficiency. Three of 13 were found to have the common autosomal dominant R264H mutation, one was found to be a compound heterozygote for two novel pathogenic mutations, and three were found to be heterozygotes for previously reported mutations shown to cause autosomal recessive MATI/III deficiency when present in homozygous or a compound heterozygous configuration. The remaining six patients had variants of unknown clinical significance or novel mutations. For the majority of individuals, methionine persisted above the normal range but trended downward over time. None of these 13 individuals was started on a low-methionine diet, and all have age-appropriate growth and development. CONCLUSION These cases show that individuals with even single changes in the MAT1A gene may have elevations in methionine identified by newborn screening, which may persist for months after birth without any clinical consequences.
Collapse
Affiliation(s)
- S Chadwick
- The Children’s Hospital of Philadelphia, Section of Metabolism, Perelman School of Medicine at the University of Pennsylvania, 3501 Civic Center blvd #9054, Philadelphia, PA 19106 USA
| | - K Fitzgerald
- The Children’s Hospital of Philadelphia, Section of Metabolism, Perelman School of Medicine at the University of Pennsylvania, 3501 Civic Center blvd #9054, Philadelphia, PA 19106 USA
| | - B Weiss
- The Children’s Hospital of Philadelphia, Section of Metabolism, Perelman School of Medicine at the University of Pennsylvania, 3501 Civic Center blvd #9054, Philadelphia, PA 19106 USA
| | - C Ficicioglu
- The Children’s Hospital of Philadelphia, Section of Metabolism, Perelman School of Medicine at the University of Pennsylvania, 3501 Civic Center blvd #9054, Philadelphia, PA 19106 USA
| |
Collapse
|
27
|
Nagao M, Tanaka T, Furujo M. Spectrum of mutations associated with methionine adenosyltransferase I/III deficiency among individuals identified during newborn screening in Japan. Mol Genet Metab 2013; 110:460-4. [PMID: 24231718 DOI: 10.1016/j.ymgme.2013.10.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 10/21/2013] [Accepted: 10/21/2013] [Indexed: 01/28/2023]
Abstract
Methionine adenosyltransferase I/III deficiency (MAT I/III deficiency) is an inborn error of metabolism that results in isolated persistent hypermethioninemia. Definitive diagnosis is now possible by molecular analyses of the MAT1A gene. Based on newborn screening (NBS) data collected between 2001 and 2012 in Hokkaido, Japan, the estimated incidence of MAT I/III deficiency was 1 in 107,850. 24 patients (13 males, 11 females) from 11 prefectures in Japan were referred to our laboratory for genetic diagnosis of MAT I/III deficiency. They were all found between 1992 and 2012 by the NBS program in each region. In these 24 individuals, we identified 12 distinct mutations; 14 patients were heterozygous for an R264H mutation; R264H caused an autosomal dominant and clinically benign phenotype in each case. The mutations in the other 10 patients showed autosomal recessive inheritance and included eight novel MAT1A mutations. Putative amino acid substitutions at R356 were observed with six alleles (three R356P, two R356Q, and one R356L). MAT I/III deficiency is not always benign because three of our cases involved brain demyelination or neurological complications. DNA testing early in life is recommended to prevent potential detrimental neurological manifestations.
Collapse
Affiliation(s)
- Masayoshi Nagao
- Department of Pediatrics and Clinical research, National Hospital Organization Hokkaido Medical Center, Sapporo, Japan.
| | | | | |
Collapse
|
28
|
Couce ML, Bóveda MD, García-Jimémez C, Balmaseda E, Vives I, Castiñeiras DE, Fernández-Marmiesse A, Fraga JM, Mudd SH, Corrales FJ. Clinical and metabolic findings in patients with methionine adenosyltransferase I/III deficiency detected by newborn screening. Mol Genet Metab 2013; 110:218-21. [PMID: 23993429 DOI: 10.1016/j.ymgme.2013.08.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 08/06/2013] [Accepted: 08/06/2013] [Indexed: 11/26/2022]
Abstract
Persistent hypermethioninemia due to mutations in the MAT1A gene is often found during newborn screening (NBS) for homocystinuria due to cystathionine beta-synthase deficiency, however, outcomes and optimal management for these patients are not well established. We carried out a multicenter study of MAT I/III-deficient patients detected by NBS in four of the Spanish regional NBS programs. Data evaluated during NBS and follow-up for 18 patients included methionine and total homocysteine levels, clinical presentation parameters, genotypes, and development quotients. The birth prevalence was 1:1:22,874. At detection 16 of the 18 patients exhibited elevations of plasma methionine above 60 μmol/L (mean 99.9 ± 38 μmol/L) and the mean value in confirmation tests was 301 μmol/L (91-899) μmol/L. All patients were asymptomatic. In four patients with more markedly elevated plasma methionines (>450 μmol/L) total homocysteine values were slightly elevated (about 20 μmol/L). The average follow-up period was 3 years 7 months (range: 2-123 months). Most patients (83%) were heterozygous for the autosomal dominant Arg264His mutation and, with one exception, presented relatively low circulating methionine concentrations (<400 μM). Additional mutations identified in patients with mean confirmatory plasma methionines above 400 μM were Arg199Cys, Leu355Arg, and a novel mutation, Thr288Ala. During continued follow-up, the patients have been asymptomatic, and, to date, no therapeutic interventions have been utilized. Therefore, the currently available evidence shows that hypermethioninemia due to heterozygous MAT1A mutations such as Arg264His is a mild condition for which no treatment is necessary.
Collapse
Affiliation(s)
- María L Couce
- Unit of Diagnosis and Treatment of Congenital Metabolic Diseases, Department of Pediatrics, Hospital Clínico Universitario de Santiago de Compostela, CIBERER, Health Research Institute of Santiago de Compostela (IDIS), A Choupana, s/n, 15706 Santiago de Compostela, A Coruña, Spain
| | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Hirabayashi K, Shiohara M, Yamada K, Sueki A, Ide Y, Takeuchi K, Hagimoto R, Kinoshita T, Yabuhara A, Mudd SH, Koike K. Neurologically normal development of a patient with severe methionine adenosyltransferase I/III deficiency after continuing dietary methionine restriction. Gene 2013; 530:104-8. [PMID: 23973726 DOI: 10.1016/j.gene.2013.08.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 07/15/2013] [Accepted: 08/10/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND There is not much information on established standard therapy for patients with severe methionine adenosyltransferase (MAT) I/III deficiency. CASE PRESENTATION We report a boy with MAT I/III deficiency, in whom plasma methionine and total homocysteine, and urinary homocystine were elevated. Molecular genetic studies showed him to have novel compound heterozygous mutations of the MAT1A gene: c.191T>A (p.M64K) and c.589delC (p.P197LfsX26). A low methionine milk diet was started at 31 days of age, and during continuing dietary methionine restriction plasma methionine levels have been maintained at less than 750 μmol/L. He is now 5 years old, and has had entirely normal physical growth and psychomotor development. CONCLUSIONS Although some severely MAT I/III deficient patients have developed neurologic abnormalities, we report here the case of a boy who has remained neurologically and otherwise normal for 5 years during methionine restriction, suggesting that perhaps such management, started in early infancy, may help prevent neurological complications.
Collapse
Affiliation(s)
- Koichi Hirabayashi
- Department of Pediatrics, Ina Central Hospital, Ina, Japan; Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Shafqat N, Muniz JR, Pilka ES, Papagrigoriou E, von Delft F, Oppermann U, Yue WW. Insight into S-adenosylmethionine biosynthesis from the crystal structures of the human methionine adenosyltransferase catalytic and regulatory subunits. Biochem J. 2013;452:27-36. [PMID: 23425511 PMCID: PMC3793261 DOI: 10.1042/bj20121580] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
MAT (methionine adenosyltransferase) utilizes L-methionine and ATP to form SAM (S-adenosylmethionine), the principal methyl donor in biological methylation. Mammals encode a liver-specific isoenzyme, MAT1A, that is genetically linked with an inborn metabolic disorder of hypermethioninaemia, as well as a ubiquitously expressed isoenzyme, MAT2A, whose enzymatic activity is regulated by an associated subunit MAT2B. To understand the molecular mechanism of MAT functions and interactions, we have crystallized the ligand-bound complexes of human MAT1A, MAT2A and MAT2B. The structures of MAT1A and MAT2A in binary complexes with their product SAM allow for a comparison with the Escherichia coli and rat structures. This facilitates the understanding of the different substrate or product conformations, mediated by the neighbouring gating loop, which can be accommodated by the compact active site during catalysis. The structure of MAT2B reveals an SDR (short-chain dehydrogenase/reductase) core with specificity for the NADP/H cofactor, and harbours the SDR catalytic triad (YxxxKS). Extended from the MAT2B core is a second domain with homology with an SDR sub-family that binds nucleotide-sugar substrates, although the equivalent region in MAT2B presents a more open and extended surface which may endow a different ligand/protein-binding capability. Together, the results of the present study provide a framework to assign structural features to the functional and catalytic properties of the human MAT proteins, and facilitate future studies to probe new catalytic and binding functions.
Collapse
|
31
|
Pajares MA, Alvarez L, Pérez-Sala D. How are mammalian methionine adenosyltransferases regulated in the liver? A focus on redox stress. FEBS Lett 2013; 587:1711-6. [PMID: 23669363 DOI: 10.1016/j.febslet.2013.04.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 04/24/2013] [Accepted: 04/28/2013] [Indexed: 12/20/2022]
Abstract
S-adenosylmethionine synthesis is a key process for cell function, and needs to be regulated at multiple levels. In recent years, advances in the knowledge of methionine adenosyltransferases have been significant. The discovery of nuclear localization of these enzymes suggests their transport to provide the methyl donor, S-adenosylmethionine, for DNA and histone methyltransferases in epigenetic modifications, opening new regulatory possibilities. Previous hypotheses considered only the cytoplasmic regulation of these enzymes, hence the need of an update to integrate recent findings. Here, we focus mainly on the liver and redox mechanisms, and their putative effects on localization and interactions of methionine adenosyltransferases.
Collapse
|
32
|
Harvey-Woodworth CN. Dimethylsulphidemia: the significance of dimethyl sulphide in extra-oral, blood borne halitosis. Br Dent J 2013; 214:E20. [DOI: 10.1038/sj.bdj.2013.329] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2012] [Indexed: 12/15/2022]
|
33
|
Brezovska-Kavrakova J, Krstevska M, Bosilkova G, Alabakovska S, Panov S, Orovchanec N. Hyperhomocysteinemia and of Methylenetetrahydrofolate Reductase (C677T) Genetic Polymorphism in Patients with Deep Vein Thrombosis. Mater Sociomed 2013; 25:170-4. [PMID: 24167429 PMCID: PMC3804432 DOI: 10.5455/msm.2013.25.170-174] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Accepted: 07/28/2013] [Indexed: 11/10/2022] Open
Abstract
AIM To determine the concentration of total plasma homocysteine (tHcy) as well as different genotypes of methylenetetrahydrofolate reductase MTHFR (C677T) in healthy subjects and patients with deep vein thrombosis (DVT). MATERIAL AND METHODS The investigation comprised a total of 160 subjects divided in two main groups: 80 healthy subjects (control group) and 80 patients with deep vein thrombosis. Concentration of tHcy was determined by spectrophotometric cyclic enzymatic method and mutation of MTHFR (C677T) gene was examined by polymerase chain reaction according to Schneider. RESULTS The results obtained for plasma tHcy in the control group were 11.62±3.43 μmol/L, while tHcy level was significantly higher in patients with deep vein thrombosis as compared to the control group, 15.19±3.63 μmol/L (р<0.001). The analysis of the results has shown that MTHFR (C677T) genetic polymorphism was responsible for mild to moderate hyperhomocysteinemia in the majority of subjects. CONCLUSION The level of tHcy in the examined patients was significantly higher in comparison with the control group. Multiple regression analysis has shown that tHcy level in CT and TT genotypes of MTHFR (C677T) was statistically higher in comparison with CC genotype of MTHFR (C677T) in both, the control group and the DVT patients.
Collapse
Affiliation(s)
| | - Marija Krstevska
- Institute of Medical and Experimental Biochemistry, Medical Faculty, Skopje, Republic of Macedonia
| | - Gordana Bosilkova
- Institute of Medical and Experimental Biochemistry, Medical Faculty, Skopje, Republic of Macedonia
| | - Sonja Alabakovska
- Institute of Medical and Experimental Biochemistry, Medical Faculty, Skopje, Republic of Macedonia
| | - Saso Panov
- Laboratory for Molecular Biology and Human Genetics, Faculty of Natural Sciences, Skopje, Republic of Macedonia
| | - Nikola Orovchanec
- Institute of Epidemiology and Biostatistics with Medical Informatics, Medical Faculty, University “Ss Cyril and Methodius” in Skopje, Republic of Macedonia
| |
Collapse
|
34
|
Furujo M, Kinoshita M, Nagao M, Kubo T. Methionine adenosyltransferase I/III deficiency: neurological manifestations and relevance of S-adenosylmethionine. Mol Genet Metab 2012; 107:253-6. [PMID: 22951388 DOI: 10.1016/j.ymgme.2012.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 08/03/2012] [Accepted: 08/03/2012] [Indexed: 11/17/2022]
Abstract
Methionine adenosyltransferase I/III (MAT I/III) deficiency, caused by mutations in the MAT1A gene, is an inherited metabolic disorder characterized by persistent hypermethioninemia, usually detected by newborn mass screening. There is a wide range of clinical manifestations, from completely asymptomatic to neurological problems associated with brain demyelination. Physiological role of S-adenosylmethionine (SAM), the metabolic product of methionine catalyzed by MAT, in the central nervous system has been investigated in vivo and in vitro, and case reports demonstrated an effectiveness of supplementary treatment of SAM in the improvement of neurological development and myelination. Methionine restriction can be an additional therapeutic strategy because hypermethioninemia alone may be neurotoxic; however, lowering methionine carries a risk to decrease the synthesis of SAM.
Collapse
Affiliation(s)
- Mahoko Furujo
- Department of Pediatrics, Okayama Medical Center, National Hospital Organization, Okayama, Japan.
| | | | | | | |
Collapse
|
35
|
Ji Y, Nordgren KKS, Chai Y, Hebbring SJ, Jenkins GD, Abo RP, Peng Y, Pelleymounter LL, Moon I, Eckloff BW, Chai X, Zhang J, Fridley BL, Yee VC, Wieben ED, Weinshilboum RM. Human liver methionine cycle: MAT1A and GNMT gene resequencing, functional genomics, and hepatic genotype-phenotype correlation. Drug Metab Dispos 2012; 40:1984-92. [PMID: 22807109 DOI: 10.1124/dmd.112.046953] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The "methionine cycle" plays a critical role in the regulation of concentrations of (S)-adenosylmethionine (AdoMet), the major biological methyl donor. We set out to study sequence variation in genes encoding the enzyme that synthesizes AdoMet in liver, methionine adenosyltransferase 1A (MAT1A) and the major hepatic AdoMet using enzyme, glycine N-methyltransferase (GNMT), as well as functional implications of that variation. We resequenced MAT1A and GNMT using DNA from 288 subjects of three ethnicities, followed by functional genomic and genotype-phenotype correlation studies performed with 268 hepatic biopsy samples. We identified 44 and 42 polymorphisms in MAT1A and GNMT, respectively. Quantitative Western blot analyses for the human liver samples showed large individual variation in MAT1A and GNMT protein expression. Genotype-phenotype correlation identified two genotyped single-nucleotide polymorphisms (SNPs), reference SNP (rs) 9471976 (corrected p = 3.9 × 10(-10)) and rs11752813 (corrected p = 1.8 × 10(-5)), and 42 imputed SNPs surrounding GNMT that were significantly associated with hepatic GNMT protein levels (corrected p values < 0.01). Reporter gene studies showed that variant alleles for both genotyped SNPs resulted in decreased transcriptional activity. Correlation analyses among hepatic protein levels for methionine cycle enzymes showed significant correlations between GNMT and MAT1A (p = 1.5 × 10(-3)) and between GNMT and betaine homocysteine methyltransferase (p = 1.6 × 10(-7)). Our discovery of SNPs that are highly associated with hepatic GNMT protein expression as well as the "coordinate regulation" of methionine cycle enzyme protein levels provide novel insight into the regulation of this important human liver biochemical pathway.
Collapse
Affiliation(s)
- Yuan Ji
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Wang YC, Chiang EPI. Low-dose methotrexate inhibits methionine S-adenosyltransferase in vitro and in vivo. Mol Med 2012; 18:423-32. [PMID: 22193356 DOI: 10.2119/molmed.2011.00048] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 12/19/2011] [Indexed: 12/29/2022] Open
Abstract
Methionine S-adenosyltransferase (MAT) catalyzes the only reaction that produces the major methyl donor in mammals. Low-dose methotrexate is the most commonly used disease-modifying antirheumatic drug in human rheumatic conditions. The present study was conducted to test the hypothesis that methotrexate inhibits MAT expression and activity in vitro and in vivo. HepG2 cells were cultured under folate restriction or in low-dose methotrexate with and without folate or methionine supplementation. Male C57BL/6J mice received methotrexate regimens that reflected low-dose clinical use in humans. S-adenosylmethionine and MAT genes, proteins and enzyme activity levels were determined. We found that methionine or folate supplementation greatly improved S-adenosylmethionine in folate-depleted cells but not in cells preexposed to methotrexate. Methotrexate but not folate depletion suppressed MAT genes, proteins and activity in vitro. Low-dose methotrexate inhibited MAT1A and MAT2A genes, MATI/II/III proteins and MAT enzyme activities in mouse tissues. Concurrent folinate supplementation with methotrexate ameliorated MAT2A reduction and restored S-adenosylmethionine in HepG2 cells. However, posttreatment folinate rescue failed to restore MAT2A reduction or S-adenosylmethionine level in cells preexposed to methotrexate. Our results provide both in vitro and in vivo evidence that low-dose methotrexate inhibits MAT genes, proteins, and enzyme activity independent of folate depletion. Because polyglutamated methotrexate stays in the hepatocytes, if methotrexate inhibits MAT in the liver, then the efficacy of clinical folinate rescue with respect to maintaining hepatic S-adenosylmethionine synthesis and normalizing the methylation reactions would be limited. These findings raise concerns on perturbed methylation reactions in humans on low-dose methotrexate. Future studies on the clinical physiological consequences of MAT inhibition by methotrexate and the potential benefits of S-adenosylmethionine supplementation on methyl group homeostasis in clinical methotrexate therapies are warranted.
Collapse
Affiliation(s)
- Yi-Cheng Wang
- Department of Food Science and Biotechnology, National Chung Hsing University, Taichung, Taiwan, Republic of China
| | | |
Collapse
|
37
|
Furujo M, Kinoshita M, Nagao M, Kubo T. S-adenosylmethionine treatment in methionine adenosyltransferase deficiency, a case report. Mol Genet Metab 2012; 105:516-8. [PMID: 22178350 DOI: 10.1016/j.ymgme.2011.11.192] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 11/18/2011] [Accepted: 11/18/2011] [Indexed: 11/16/2022]
Abstract
Reported is a female patient with methionine adenosyltransferase I/III (MAT I/III) deficiency, who was found to have pronounced hypermethioninemia on newborn mass spectroscopy screening, and had two compound heterozygous missense mutations in the gene encoding human MAT1A protein. Hypermethioninemia persisted and her mental development was deficient. At 4 years and 8 months, we started with the supplementary treatment of S-adenosylmethionine, the metabolic product of methionine catalyzed by MAT, which was effective in her neurological development.
Collapse
Affiliation(s)
- Mahoko Furujo
- Department of Pediatrics, National Hospital Organization, Okayama Medical Center, Okayama, Japan.
| | | | | | | |
Collapse
|
38
|
Martins E, Marcão A, Bandeira A, Fonseca H, Nogueira C, Vilarinho L. Methionine Adenosyltransferase I/III Deficiency in Portugal: High Frequency of a Dominantly Inherited Form in a Small Area of Douro High Lands. JIMD Rep 2012; 6:107-12. [PMID: 23430947 DOI: 10.1007/8904_2011_124] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Revised: 12/10/2011] [Accepted: 12/14/2011] [Indexed: 01/11/2023] Open
Abstract
Methionine adenosyltransferase deficiency (MAT I/III deficiency) is an inborn error of metabolism resulting in isolated hypermethioninemia, and usually inherited as an autosomal recessive trait, although a dominant form has been reported in several families.During the last 6 years, approximately 520,000 newborns were screened in the Portuguese Newborn Screening Laboratory by MS/MS, and 21 cases of persistent hypermethioninemia were found. One case was confirmed to be a deficiency of cystathionine β-synthase and 20 cases were confirmed by MAT1A gene analysis to have an elevation of methionine due to MAT I/III deficiency, which indicates an incidence for this condition of 1/26,000. Twelve of the MAT I/III deficient newborns, belonging to 11 families, were identified in the northern region of Portugal and sent to the same treatment center, where they are under follow-up. Clinical, biochemical, and genetic characteristics of individuals from these 11 families are presented. Plasma methionine and homocysteine concentrations were found to be moderately increased in all newborns, and molecular analysis revealed that they all were heterozygous for R264H mutation. Normal growth, development, and neurological examination were observed in all cases, and cerebral MRI performed in six cases revealed myelination abnormalities in one case. Plasma methionine concentration for all 12 cases was always below 300 μM, and they are all on a normal diet for their age.
Collapse
Affiliation(s)
- E Martins
- Hospital de Crianças Maria Pia, Centro Hospitalar do Porto, Rua da Boavista, 827, 4050-111, Porto, Portugal,
| | | | | | | | | | | |
Collapse
|
39
|
|
40
|
Abstract
The vitamin folate functions within the cell as a carrier of one-carbon units. The requirement for one-carbon transfers is ubiquitous and all mammalian cells carry out folate dependent reactions. In recent years, low folate status has been linked to risk of numerous adverse health conditions throughout life from birth defects and complications of pregnancy to cardiovascular disease, cancer and cognitive dysfunction in the elderly. In many instances inadequate intake of folate seems to be the primary contributor but there is also evidence that an underlying genetic susceptibility can play a modest role by causing subtle alterations in the availability, metabolism or distribution of intermediates in folate related pathways. Folate linked one-carbon units are essential for DNA synthesis and repair and as a source of methyl groups for biological methylation reactions. The notion of common genetic variants being linked to risk of disease was relatively novel in 1995 when the first functional folate-related polymorphism was discovered. Numerous polymorphisms have now been identified in folate related genes and have been tested for functionality either as a modifier of folate status or as being associated with risk of disease. Moreover, there is increasing research into the importance of folate-derived one-carbon units for DNA and histone methylation reactions, which exert crucial epigenetic control over cellular protein synthesis. It is thus becoming clear that genetic aspects of folate metabolism are wide-ranging and may touch on events as disparate as prenatal imprinting to cancer susceptibility. This chapter will review the current knowledge in this area.
Collapse
Affiliation(s)
- Anne M Molloy
- School of Medicine, Trinity College Dublin, Dublin 2, Ireland,
| |
Collapse
|
41
|
Affiliation(s)
- María A Pajares
- Instituto de Investigaciones Biomédicas "Alberto Sols" (CSIC-UAM), Madrid Spain
| | | |
Collapse
|
42
|
Nordgren KKS, Peng Y, Pelleymounter LL, Moon I, Abo R, Feng Q, Eckloff B, Yee VC, Wieben E, Weinshilboum RM. Methionine adenosyltransferase 2A/2B and methylation: gene sequence variation and functional genomics. Drug Metab Dispos 2011; 39:2135-47. [PMID: 21813468 DOI: 10.1124/dmd.111.040857] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Methionine adenosyltransferase (MAT) catalyzes the synthesis of S-adenosylmethionine, the major biological methyl donor. MAT1A and MAT2A encode two distinct MAT isoforms in mammals. MAT2A is expressed in nonhepatic tissues, whereas MAT1A is expressed in the liver. A third gene, MAT2B, encodes a MAT2A regulatory protein. We resequenced MAT2A and MAT2B exons, splice junctions, and flanking regions using 288 DNA samples from three ethnic groups and also imputed additional single nucleotide polymorphisms (SNPs) across both genes using data from the 1000 Genomes Project. For MAT2A, resequencing identified 74 polymorphisms, including two nonsynonymous (ns) SNPs. Functional genomic studies of wild type and the two MAT2A variant allozymes (Val11 and Val205) showed that the Val11 allozyme had approximately 40% decreases in levels of enzyme activity and immunoreactive protein after COS-1 cell transfection. For MAT2B, 44 polymorphisms, 2 nonsynonymous, were identified during resequencing. Neither of the two MAT2B nsSNPs displayed alterations in levels of protein. Imputation using 1000 Genomes Project data resulted in 1730 additional MAT2A and 1997 MAT2B polymorphisms within ± 200 kilobases of each gene, respectively. Coexpression of MAT2A and MAT2B in COS-1 cells resulted in significantly increased MAT enzyme activity that correlated with increased MAT2A and MAT2B immunoreactive protein, apparently as a result of decreased degradation. Finally, studies of mRNA expression in lymphoblastoid cells showed that 7 SNPs in MAT2A and 16 SNPs in MAT2B were significantly associated with mRNA expression with p < 0.01. These observations provide a foundation for future mechanistic and clinical translational pharmacogenomic studies of MAT2A/2B.
Collapse
Affiliation(s)
- Kendra K S Nordgren
- Division of Clinical Pharmacology, Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Zaidi SHE, Faiyaz-Ul-Haque M, Shuaib T, Balobaid A, Rahbeeni Z, Abalkhail H, Al-Abdullatif A, Al-Hassnan Z, Peltekova I, Al-Owain M. Clinical and molecular findings of 13 families from Saudi Arabia and a family from Sudan with homocystinuria. Clin Genet 2011; 81:563-70. [DOI: 10.1111/j.1399-0004.2011.01690.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
44
|
Abstract
This review covers briefly the major conditions, genetic and non-genetic, sometimes leading to abnormally elevated methionine, with emphasis on recent developments. A major aim is to assist in the differential diagnosis of hypermethioninemia. The genetic conditions are: (1) Homocystinuria due to cystathionine β-synthase (CBS) deficiency. At least 150 different mutations in the CBS gene have been identified since this deficiency was established in 1964. Hypermethioninemia is due chiefly to remethylation of the accumulated homocysteine. (2) Deficient activity of methionine adenosyltransferases I and III (MAT I/III), the isoenzymes the catalytic subunit of which are encoded by MAT1A. Methionine accumulates because its conversion to S-adenosylmethionine (AdoMet) is impaired. (3) Glycine N-methyltrasferase (GNMT) deficiency. Disruption of a quantitatively major pathway for AdoMet disposal leads to AdoMet accumulation with secondary down-regulation of methionine flux into AdoMet. (4) S-adenosylhomocysteine (AdoHcy) hydrolase (AHCY) deficiency. Not being catabolized normally, AdoHcy accumulates and inhibits many AdoMet-dependent methyltransferases, producing accumulation of AdoMet and, thereby, hypermethioninemia. (5) Citrin deficiency, found chiefly in Asian countries. Lack of this mitochondrial aspartate-glutamate transporter may produce (usually transient) hypermethioninemia, the immediate cause of which remains uncertain. (6) Fumarylacetoacetate hydrolase (FAH) deficiency (tyrosinemia type I) may lead to hypermethioninemia secondary either to liver damage and/or to accumulation of fumarylacetoacetate, an inhibitor of the high K(m) MAT. Additional possible genetic causes of hypermethioninemia accompanied by elevations of plasma AdoMet include mitochondrial disorders (the specificity and frequency of which remain to be elucidated). Non-genetic conditions include: (a) Liver disease, which may cause hypermethioninemia, mild, or severe. (b) Low-birth-weight and/or prematurity which may cause transient hypermethioninemia. (c) Ingestion of relatively large amounts of methionine which, even in full-term, normal-birth-weight babies may cause hypermethioninemia.
Collapse
Affiliation(s)
- S Harvey Mudd
- Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD, USA.
| |
Collapse
|
45
|
Fernández-Irigoyen J, Santamaría E, Chien YH, Hwu WL, Korman SH, Faghfoury H, Schulze A, Hoganson GE, Stabler SP, Allen RH, Wagner C, Mudd SH, Corrales FJ. Enzymatic activity of methionine adenosyltransferase variants identified in patients with persistent hypermethioninemia. Mol Genet Metab 2010; 101:172-7. [PMID: 20675163 DOI: 10.1016/j.ymgme.2010.07.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 07/08/2010] [Accepted: 07/08/2010] [Indexed: 01/12/2023]
Abstract
Methionine adenosyltransferases (MAT's) are central enzymes in living organisms that have been conserved with a high degree of homology among species. In the liver, MAT I and III, tetrameric and dimeric isoforms of the same catalytic subunit encoded by the gene MAT1A, account for the predominant portion of total body synthesis of S-adenosylmethionine (SAM), a versatile sulfonium ion-containing molecule involved in a variety of vital metabolic reactions and in the control of hepatocyte proliferation and differentiation. During the past 15years 28 MAT1A mutations have been described in patients with elevated plasma methionines, total homocysteines at most only moderately elevated, and normal levels of tyrosine and other aminoacids. In this study we describe functional analyses that determine the MAT and tripolyphosphatase (PPPase) activities of 18 MAT1A variants, six of them novel, and none of them previously assayed for activity. With the exception of G69S and Y92H, all recombinant proteins showed impairment (usually severe) of MAT activity. Tripolyphosphate (PPPi) hydrolysis was decreased only in some mutant proteins but, when it was decreased MAT activity was always also impaired.
Collapse
Affiliation(s)
- Joaquín Fernández-Irigoyen
- Division of Hepatology and Gene Therapy, Proteomics Unit, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Korendyaseva TK, Martinov MV, Dudchenko AM, Vitvitsky VM. Distribution of methionine between cells and incubation medium in suspension of rat hepatocytes. Amino Acids 2010; 39:1281-9. [PMID: 20309593 DOI: 10.1007/s00726-010-0563-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2009] [Accepted: 03/10/2010] [Indexed: 01/18/2023]
Abstract
Methionine is an essential amino acid involved in many significant intracellular processes. Aberrations in methionine metabolism are associated with a number of complex pathologies. Liver plays a key role in regulation of blood methionine level. Investigation of methionine distribution between hepatocytes and medium is crucial for understanding the mechanisms of this regulation. For the first time, we analyzed the distribution of methionine between hepatocytes and incubation medium using direct measurements of methionine concentrations. Our results revealed a fast and reversible transport of methionine through the cell membrane that provides almost uniform distribution of methionine between hepatocytes and incubation medium. The steady-state ratio between intracellular and extracellular methionine concentrations was established within a few minutes. This ratio was found to be 1.06±0.38, 0.89±0.26, 0.67±0.16 and 0.82±0.06 at methionine concentrations in the medium of 64±19, 152±39, 413±55, and 1,204±104 μmol/L, respectively. The fast and uniform distribution of methionine between hepatocytes and extracellular compartments provides a possibility for effective regulation of blood methionine levels due to methionine metabolism in hepatocytes.
Collapse
Affiliation(s)
- Tatyana K Korendyaseva
- National Research Center for Hematology, Novozykovsky proezd, 4a, Moscow, 125167, Russia
| | | | | | | |
Collapse
|
47
|
Oh SJ, Hong YH, Lee YW, Lee DH. Spectrum of patients with hypermethioninemia based on neonatal screening tests over 14 years. Korean J Pediatr 2010. [DOI: 10.3345/kjp.2010.53.3.329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Se Jung Oh
- Department of Pediatrics, College of Medicine, Soonchunhyang University, Seoul, Korea
| | - Yong Hee Hong
- Department of Pediatrics, College of Medicine, Soonchunhyang University, Seoul, Korea
| | - Yong Wha Lee
- Department of Laboratory Medicine & Genetics, Soonchunhyang University Bucheon Hospital and Soonchunhyang University College of Medicine, Korea
| | - Dong Hwan Lee
- Department of Pediatrics, College of Medicine, Soonchunhyang University, Seoul, Korea
| |
Collapse
|
48
|
Martinov MV, Vitvitsky VM, Banerjee R, Ataullakhanov FI. The logic of the hepatic methionine metabolic cycle. Biochim Biophys Acta 2009; 1804:89-96. [PMID: 19833238 DOI: 10.1016/j.bbapap.2009.10.004] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 10/02/2009] [Accepted: 10/06/2009] [Indexed: 12/18/2022]
Abstract
This review describes our current understanding of the "traffic lights" that regulate sulfur flow through the methionine bionetwork in liver, which supplies two major homeostatic systems governing cellular methylation and antioxidant potential. Theoretical concepts derived from mathematical modeling of this metabolic nexus provide insights into the properties of this system, some of which seem to be paradoxical at first glance. Cellular needs supported by this network are met by use of parallel metabolic tracks that are differentially controlled by intermediates in the pathway. A major task, i.e. providing cellular methylases with the methylating substrate, S-adenosylmethionine, is met by flux through the methionine adenosyltransferase I isoform. On the other hand, a second important function, i.e., stabilization of the blood methionine concentration in the face of high dietary intake of this amino acid, is achieved by switching to an alternative isoform, methionine adenosyltransferase III, and to glycine N-methyl transferase, which together bypass the first two reactions in the methionine cycle. This regulatory strategy leads to two metabolic modes that differ in metabolite concentrations and metabolic rates almost by an order of magnitude. Switching between these modes occurs in a narrow trigger zone of methionine concentration. Complementary experimental and theoretical analyses of hepatic methionine metabolism have been richly informative and have the potential to illuminate its response to oxidative challenge, to methionine restriction and lifespan extension studies and to diseases resulting from deficiencies at specific loci in this pathway.
Collapse
Affiliation(s)
- M V Martinov
- National Research Center for Hematology, RAMS, Moscow, Russia
| | | | | | | |
Collapse
|
49
|
Abstract
During the last decade much important new information relating to the metabolic pathway from methionine to homocysteine has been gained. Interest has been stimulated by the discovery of two novel disorders, glycine N-methyltransferase deficiency and S-adenosylhomocysteine hydrolase deficiency. Another disorder in this pathway, methionine adenosyltransferase deficiency, has been increasingly detected, thanks to the expansion of newborn screening programmes by tandem mass spectrometry technology. These significant steps allow important insight into the pathogenesis of these three disorders, as well as into the mechanisms of damage to various organs (liver, brain, muscle) and point to the relevance of these disorders for crucial biological processes such as methylation, transsulfuration or carcinogenesis in mammals, the pathogenesis of numerous pathological conditions, in particular those associated with hyperhomocysteinaemia, the action and possible toxicity of some drugs or consequences of nutritional variations. This review summarizes current knowledge of three inherited disorders in this metabolic pathway and draws attention to their much broader significance for human health and understanding of important biological processes.
Collapse
Affiliation(s)
- Ivo Barić
- Department of Pediatrics, University Hospital Center and School of Medicine, Zagreb, Croatia.
| |
Collapse
|
50
|
Abstract
Methionine adenosyltransferases (MATs) are the family of enzymes that synthesize the main biological methyl donor, S-adenosylmethionine. The high sequence conservation among catalytic subunits from bacteria and eukarya preserves key residues that control activity and oligomerization, which is reflected in the protein structure. However, structural differences among complexes with substrates and products have led to proposals of several reaction mechanisms. In parallel, folding studies begin to explain how the three intertwined domains of the catalytic subunit are produced, and to highlight the importance of certain intermediates in attaining the active final conformation. This review analyzes the available structural data and proposes a consensus interpretation that facilitates an understanding of the pathological problems derived from impairment of MAT function. In addition, new research opportunities directed toward clarification of aspects that remain obscure are also identified.
Collapse
Affiliation(s)
- G D Markham
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | | |
Collapse
|