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Pilesi E, Tesoriere G, Ferriero A, Mascolo E, Liguori F, Argirò L, Angioli C, Tramonti A, Contestabile R, Volontè C, Vernì F. Vitamin B6 deficiency cooperates with oncogenic Ras to induce malignant tumors in Drosophila. Cell Death Dis 2024; 15:388. [PMID: 38830901 PMCID: PMC11148137 DOI: 10.1038/s41419-024-06787-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 05/26/2024] [Accepted: 05/28/2024] [Indexed: 06/05/2024]
Abstract
Vitamin B6 is a water-soluble vitamin which possesses antioxidant properties. Its catalytically active form, pyridoxal 5'-phosphate (PLP), is a crucial cofactor for DNA and amino acid metabolism. The inverse correlation between vitamin B6 and cancer risk has been observed in several studies, although dietary vitamin B6 intake sometimes failed to confirm this association. However, the molecular link between vitamin B6 and cancer remains elusive. Previous work has shown that vitamin B6 deficiency causes chromosome aberrations (CABs) in Drosophila and human cells, suggesting that genome instability may correlate the lack of this vitamin to cancer. Here we provide evidence in support of this hypothesis. Firstly, we show that PLP deficiency, induced by the PLP antagonists 4-deoxypyridoxine (4DP) or ginkgotoxin (GT), promoted tumorigenesis in eye larval discs transforming benign RasV12 tumors into aggressive forms. In contrast, PLP supplementation reduced the development of tumors. We also show that low PLP levels, induced by 4DP or by silencing the sgllPNPO gene involved in PLP biosynthesis, worsened the tumor phenotype in another Drosophila cancer model generated by concomitantly activating RasV12 and downregulating Discs-large (Dlg) gene. Moreover, we found that RasV12 eye discs from larvae reared on 4DP displayed CABs, reactive oxygen species (ROS) and low catalytic activity of serine hydroxymethyltransferase (SHMT), a PLP-dependent enzyme involved in thymidylate (dTMP) biosynthesis, in turn required for DNA replication and repair. Feeding RasV12 4DP-fed larvae with PLP or ascorbic acid (AA) plus dTMP, rescued both CABs and tumors. The same effect was produced by overexpressing catalase in RasV12 DlgRNAi 4DP-fed larvae, thus allowing to establish a relationship between PLP deficiency, CABs, and cancer. Overall, our data provide the first in vivo demonstration that PLP deficiency can impact on cancer by increasing genome instability, which is in turn mediated by ROS and reduced dTMP levels.
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Affiliation(s)
- Eleonora Pilesi
- Dept. of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185, Rome, Italy
| | - Giulia Tesoriere
- Dept. of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185, Rome, Italy
| | - Angelo Ferriero
- Dept. of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185, Rome, Italy
| | - Elisa Mascolo
- Dept. of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185, Rome, Italy
| | - Francesco Liguori
- Experimental Neuroscience and Neurological Disease Models, IRCCS Santa Lucia Foundation, 00143, Rome, Italy
- CNR, Institute for Systems Analysis and Computer Science, 00185, Rome, Italy
| | - Luca Argirò
- Dept. of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185, Rome, Italy
| | - Chiara Angioli
- Dept. of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185, Rome, Italy
| | - Angela Tramonti
- Institute of Molecular Biology and Pathology, 00185, Rome, Italy
| | - Roberto Contestabile
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza, University of Rome, 00185, Rome, Italy
- Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza, University of Rome, 00185, Rome, Italy
| | - Cinzia Volontè
- Experimental Neuroscience and Neurological Disease Models, IRCCS Santa Lucia Foundation, 00143, Rome, Italy
- CNR, Institute for Systems Analysis and Computer Science, 00185, Rome, Italy
| | - Fiammetta Vernì
- Dept. of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185, Rome, Italy.
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Petrova B, Maynard AG, Wang P, Kanarek N. Regulatory mechanisms of one-carbon metabolism enzymes. J Biol Chem 2023; 299:105457. [PMID: 37949226 PMCID: PMC10758965 DOI: 10.1016/j.jbc.2023.105457] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 10/18/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023] Open
Abstract
One-carbon metabolism is a central metabolic pathway critical for the biosynthesis of several amino acids, methyl group donors, and nucleotides. The pathway mostly relies on the transfer of a carbon unit from the amino acid serine, through the cofactor folate (in its several forms), and to the ultimate carbon acceptors that include nucleotides and methyl groups used for methylation of proteins, RNA, and DNA. Nucleotides are required for DNA replication, DNA repair, gene expression, and protein translation, through ribosomal RNA. Therefore, the one-carbon metabolism pathway is essential for cell growth and function in all cells, but is specifically important for rapidly proliferating cells. The regulation of one-carbon metabolism is a critical aspect of the normal and pathological function of the pathway, such as in cancer, where hijacking these regulatory mechanisms feeds an increased need for nucleotides. One-carbon metabolism is regulated at several levels: via gene expression, posttranslational modification, subcellular compartmentalization, allosteric inhibition, and feedback regulation. In this review, we aim to inform the readers of relevant one-carbon metabolism regulation mechanisms and to bring forward the need to further study this aspect of one-carbon metabolism. The review aims to integrate two major aspects of cancer metabolism-signaling downstream of nutrient sensing and one-carbon metabolism, because while each of these is critical for the proliferation of cancerous cells, their integration is critical for comprehensive understating of cellular metabolism in transformed cells and can lead to clinically relevant insights.
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Affiliation(s)
- Boryana Petrova
- Department of Pathology, Boston Children's Hospital, Boston, Massachusetts, USA; Harvard Medical School, Boston, Massachusetts, USA
| | - Adam G Maynard
- Department of Pathology, Boston Children's Hospital, Boston, Massachusetts, USA; Graduate Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, Massachusetts, USA
| | - Peng Wang
- Department of Pathology, Boston Children's Hospital, Boston, Massachusetts, USA; Harvard Medical School, Boston, Massachusetts, USA
| | - Naama Kanarek
- Department of Pathology, Boston Children's Hospital, Boston, Massachusetts, USA; Harvard Medical School, Boston, Massachusetts, USA; The Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA.
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3
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Ma W, Liu R, Zhao K, Zhong J. Vital role of SHMT2 in diverse disease. Biochem Biophys Res Commun 2023; 671:160-165. [PMID: 37302290 DOI: 10.1016/j.bbrc.2023.05.108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 05/25/2023] [Indexed: 06/13/2023]
Abstract
One-carbon metabolism is essential for our human cells to carry out nucleotide synthesis, methylation, and reductive metabolism through one-carbon units, and these pathways ensure the high proliferation rate of cancer cells. Serine hydroxymethyltransferase 2 (SHMT2) is a key enzyme in one-carbon metabolism. This enzyme can convert serine into a one-carbon unit bound to tetrahydrofolate and glycine, ultimately supporting the synthesis of thymidine and purines and promoting the growth of cancer cells. Due to SHMT2's crucial role in the one-carbon cycle, it is ubiquitous in human cells and even in all organisms and highly conserved. Here, we summarize the impact of SHMT2 on the progression of various cancers to highlight its potential use in the development of cancer treatments.
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Affiliation(s)
- Wenqi Ma
- Central Hospital Affiliated to Shandong First Medical University, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, 250013, China
| | - Ronghan Liu
- Central Hospital Affiliated to Shandong First Medical University, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, 250013, China
| | - Kai Zhao
- Central Hospital Affiliated to Shandong First Medical University, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, 250013, China
| | - Jiangbo Zhong
- Central Hospital Affiliated to Shandong First Medical University, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, 250013, China.
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4
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Pilesi E, Angioli C, Graziani C, Parroni A, Contestabile R, Tramonti A, Vernì F. A gene-nutrient interaction between vitamin B6 and serine hydroxymethyltransferase (SHMT) affects genome integrity in Drosophila. J Cell Physiol 2023. [PMID: 37183313 DOI: 10.1002/jcp.31033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 04/06/2023] [Accepted: 04/18/2023] [Indexed: 05/16/2023]
Abstract
Pyridoxal 5'-phosphate (PLP), the catalytically active form of vitamin B6, participates as a cofactor to one carbon (1C) pathway that produces precursors for DNA metabolism. The concerted action of PLP-dependent serine hydroxymethyltransferase (SHMT) and thymidylate synthase (TS) leads to the biosynthesis of thymidylate (dTMP), which plays an essential function in DNA synthesis and repair. PLP deficiency causes chromosome aberrations (CABs) in Drosophila and human cells, rising the hypothesis that an altered 1C metabolism may be involved. To test this hypothesis, we used Drosophila as a model system and found, firstly, that in PLP deficient larvae SHMT activity is reduced by 40%. Second, we found that RNAi-induced SHMT depletion causes chromosome damage rescued by PLP supplementation and strongly exacerbated by PLP depletion. RNAi-induced TS depletion causes severe chromosome damage, but this is only slightly enhanced by PLP depletion. dTMP supplementation rescues CABs in both PLP-deficient and PLP-proficient SHMTRNAi . Altogether these data suggest that a reduction of SHMT activity caused by PLP deficiency contributes to chromosome damage by reducing dTMP biosynthesis. In addition, our work brings to light a gene-nutrient interaction between SHMT decreased activity and PLP deficiency impacting on genome stability that may be translated to humans.
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Affiliation(s)
- Eleonora Pilesi
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Chiara Angioli
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Claudio Graziani
- Department of Biochemical Sciences "A. Rossi Fanelli", Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
| | - Alessia Parroni
- Department of Biochemical Sciences "A. Rossi Fanelli", Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
- Institute of Molecular Biology and Pathology, National Research Council (IBPM-CNR), Rome, Italy
| | - Roberto Contestabile
- Department of Biochemical Sciences "A. Rossi Fanelli", Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
| | - Angela Tramonti
- Department of Biochemical Sciences "A. Rossi Fanelli", Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
- Institute of Molecular Biology and Pathology, National Research Council (IBPM-CNR), Rome, Italy
| | - Fiammetta Vernì
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
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Lifestyle and dietary factors, iron status and one-carbon metabolism polymorphisms in a sample of Italian women and men attending a Transfusion Medicine Unit: a cross-sectional study. Br J Nutr 2022:1-6. [DOI: 10.1017/s0007114522003245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Abstract
Iron (Fe) status among healthy male and female blood donors, aged 18–65 years, is estimated. General characteristics and lifestyle factors, dietary habits and major one-carbon metabolism-related polymorphisms were also investigated. An explorative cross-sectional study design was used to examine a sample of blood donors attending the Transfusion Medicine Unit of the Verona University Hospital, Italy. From April 2016 to May 2018, 499 subjects were enrolled (255 men, 244 women, 155 of whom of childbearing age). Major clinical characteristics including lifestyle, dietary habits and Fe status were analysed. The MTHFR 677C > T, cSHMT 1420C > T, DHFR 19bp ins/del and RFC1 80G > A polymorphisms were also assayed. Mean plasma concentrations of Fe and ferritin were 16·6 µmol/l (95 % CI 16·0, 17·2) and 33·8 µg/l (95 % CI 31·5, 36·2), respectively. Adequate plasma Fe concentrations (> 10·74 µmol/l) were detected in 84·3 % and adequate ferritin concentrations (20–200 µg/l) was found in 72·5 % of the whole cohort. Among the folate-related polymorphisms analysed, carriers of the DHFR 19bp del/del mutant allele showed lower ferritin concentration when compared with DHFR 19bp ins/del genotypes. In a sample of Italian healthy blood donors, adequate plasma concentrations of Fe and ferritin were reached in a large proportion of subjects. The relationship of Fe status with lifestyle factors and folate-related polymorphisms requires more investigation to clarify further gene–nutrient interactions between folate and Fe metabolism.
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Pashaei S, Yarani R, Mohammadi P, Emami Aleagha MS. The potential roles of amino acids and their major derivatives in the management of multiple sclerosis. Amino Acids 2022; 54:841-858. [PMID: 35471671 DOI: 10.1007/s00726-022-03162-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 04/05/2022] [Indexed: 11/29/2022]
Abstract
Recently, we reviewed the important role of carbohydrates and lipids metabolism in different clinical aspects of multiple sclerosis (MS) disease. In the current paper, we aimed to review the contribution of amino acids and their major derivatives to different clinical outcomes of the disease, including etiology, pathogenesis, diagnosis, prognosis, and treatment. In this line, Thr (threonine), Phe (phenylalanine), Glu (glutamate), Trp (tryptophan), and Sero (serotonin) are the main examples of biomolecules that have been suggested for MS therapy. It has been concluded that different amino acids and their derivatives might be considered prominent tools for the clinical management of MS disease.
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Affiliation(s)
- Somayeh Pashaei
- Department of Clinical Biochemistry, School of Medicine, Kermanshah University of Medical Sciences, Sorkhe-Ligeh Street, Kermanshah, Iran
| | - Reza Yarani
- Translational Type 1 Diabetes Biology, Department of Clinical Research, Steno Diabetes Center Copenhagen, Copenhagen, Denmark.,Interventional Regenerative Medicine and Imaging Laboratory, Department of Radiology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Pantea Mohammadi
- Medical Biology Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Mohammad Sajad Emami Aleagha
- Department of Clinical Biochemistry, School of Medicine, Kermanshah University of Medical Sciences, Sorkhe-Ligeh Street, Kermanshah, Iran.
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7
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Quevedo-Ocampo J, Escobedo-Calvario A, Souza-Arroyo V, Miranda-Labra RU, Bucio-Ortiz L, Gutiérrez-Ruiz MC, Chávez-Rodríguez L, Gomez-Quiroz LE. Folate Metabolism in Hepatocellular Carcinoma. What Do We Know So Far? Technol Cancer Res Treat 2022; 21:15330338221144446. [PMID: 36503290 DOI: 10.1177/15330338221144446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cancer cells are characterized by accelerated proliferation and an outstanding adaptation of their metabolic pathways to meet energy demands. The folate cycle, also known as folate metabolism or one-carbon metabolism, through enzymatic interconversions, provides metabolites necessary for nucleotide synthesis, methylation, and reduction power, helping to maintain the high rate of proliferation; therefore, the study of this metabolic pathway is of great importance in the study of cancer. Moreover, multiple enzymes involved in this cycle have been implicated in different types of cancer, corroborating the cell's adaptations under this pathology. During the last decade, nonalcoholic fatty liver disease has emerged as the leading etiology related to the rise in the incidence and deaths of hepatocellular carcinoma. Specifically, cholesterol accumulation has been a determinant promoter of tumor formation, with solid evidence that an enriched-cholesterol diet plays a crucial role in accelerating the development of an aggressive subtype of hepatocellular carcinoma compared to other models. In this review, we will discuss the most recent findings to understand the contribution of folate metabolism to cancer cells and tumor microenvironment while creating a link between the dynamics given by cholesterol and methylenetetrahydrofolate dehydrogenase 1-like, a key enzyme of the cycle located in the mitochondrial compartment.
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Affiliation(s)
- Jaqueline Quevedo-Ocampo
- Área de Medicina Experimental y Traslacional, Departamento de Ciencias de la Salud, 27786Universidad Autónoma Metropolitana-Iztapalapa, Mexico City, Mexico.,Posgrado en Biología Experimental, DCBS, Universidad Autónoma Metrolitana-Iztapalapa, Mexico City, Mexico
| | - Alejandro Escobedo-Calvario
- Área de Medicina Experimental y Traslacional, Departamento de Ciencias de la Salud, 27786Universidad Autónoma Metropolitana-Iztapalapa, Mexico City, Mexico.,Posgrado en Biología Experimental, DCBS, Universidad Autónoma Metrolitana-Iztapalapa, Mexico City, Mexico
| | - Verónica Souza-Arroyo
- Área de Medicina Experimental y Traslacional, Departamento de Ciencias de la Salud, 27786Universidad Autónoma Metropolitana-Iztapalapa, Mexico City, Mexico.,Laboratorio de Medicina Experimental, Unidad de Medicina Traslacional IIB/UNAM, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Roxana U Miranda-Labra
- Área de Medicina Experimental y Traslacional, Departamento de Ciencias de la Salud, 27786Universidad Autónoma Metropolitana-Iztapalapa, Mexico City, Mexico.,Laboratorio de Medicina Experimental, Unidad de Medicina Traslacional IIB/UNAM, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Leticia Bucio-Ortiz
- Área de Medicina Experimental y Traslacional, Departamento de Ciencias de la Salud, 27786Universidad Autónoma Metropolitana-Iztapalapa, Mexico City, Mexico.,Laboratorio de Medicina Experimental, Unidad de Medicina Traslacional IIB/UNAM, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - María C Gutiérrez-Ruiz
- Área de Medicina Experimental y Traslacional, Departamento de Ciencias de la Salud, 27786Universidad Autónoma Metropolitana-Iztapalapa, Mexico City, Mexico.,Laboratorio de Medicina Experimental, Unidad de Medicina Traslacional IIB/UNAM, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Lisette Chávez-Rodríguez
- Área de Medicina Experimental y Traslacional, Departamento de Ciencias de la Salud, 27786Universidad Autónoma Metropolitana-Iztapalapa, Mexico City, Mexico.,Posgrado en Biología Experimental, DCBS, Universidad Autónoma Metrolitana-Iztapalapa, Mexico City, Mexico
| | - Luis E Gomez-Quiroz
- Área de Medicina Experimental y Traslacional, Departamento de Ciencias de la Salud, 27786Universidad Autónoma Metropolitana-Iztapalapa, Mexico City, Mexico.,Laboratorio de Medicina Experimental, Unidad de Medicina Traslacional IIB/UNAM, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
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8
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Fiddler JL, Xiu Y, Blum JE, Lamarre SG, Phinney WN, Stabler SP, Brosnan ME, Brosnan JT, Thalacker-Mercer AE, Field MS. Reduced Shmt2 Expression Impairs Mitochondrial Folate Accumulation and Respiration, and Leads to Uracil Accumulation in Mouse Mitochondrial DNA. J Nutr 2021; 151:2882-2893. [PMID: 34383924 DOI: 10.1093/jn/nxab211] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/24/2021] [Accepted: 06/08/2021] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Adequate cellular thymidylate (dTMP) pools are essential for preservation of nuclear and mitochondrial genome stability. Previous studies have indicated that disruption in nuclear dTMP synthesis leads to increased uracil misincorporation into DNA, affecting genome stability. To date, the effects of impaired mitochondrial dTMP synthesis in nontransformed tissues have been understudied. OBJECTIVES This study aimed to determine the effects of decreased serine hydroxymethyltransferase 2 (Shmt2) expression and dietary folate deficiency on mitochondrial DNA (mtDNA) integrity and mitochondrial function in mouse tissues. METHODS Liver mtDNA content, and uracil content in liver mtDNA, were measured in Shmt2+/- and Shmt2+/+ mice weaned onto either a folate-sufficient control diet (2 mg/kg folic acid; C) or a modified diet lacking folic acid (0 mg/kg folic acid) for 7 wk. Shmt2+/- and Shmt2+/+ mouse embryonic fibroblast (MEF) cells were cultured in defined culture medium containing either 0 or 25 nM folate (6S-5-formyl-tetrahydrofolate, folinate) to assess proliferative capacity and mitochondrial function. Chi-square tests, linear mixed models, and 2-factor ANOVA with Tukey post hoc analyses were used to analyze data. RESULTS Shmt2 +/- mice exhibited a 48%-67% reduction in SHMT2 protein concentrations in tissues. Interestingly, Shmt2+/- mice consuming the folate-sufficient C diet exhibited a 25% reduction in total folate in liver mitochondria. There was also a >20-fold increase in uracil in liver mtDNA in Shmt2+/- mice consuming the C diet, and dietary folate deficiency also increased uracil content in mouse liver mtDNA from both Shmt2+/+ and Shmt2+/- mice. Furthermore, decreased Shmt2 expression in MEF cells reduced cell proliferation, mitochondrial membrane potential, and oxygen consumption rate. CONCLUSIONS This study demonstrates that Shmt2 heterozygosity and dietary folate deficiency impair mitochondrial dTMP synthesis in mice, as evidenced by the increased uracil in mtDNA. In addition, Shmt2 heterozygosity impairs mitochondrial function in MEF cells. These findings suggest that elevated uracil in mtDNA may impair mitochondrial function.
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Affiliation(s)
- Joanna L Fiddler
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Yuwen Xiu
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Jamie E Blum
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Simon G Lamarre
- Department of Biology, University of Moncton, Moncton, New Brunswick, Canada
| | | | - Sally P Stabler
- Department of Medicine, University of Colorado, Aurora, CO, USA
| | - Margaret E Brosnan
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - John T Brosnan
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Anna E Thalacker-Mercer
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Martha S Field
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
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Zeng Y, Zhang J, Xu M, Chen F, Zi R, Yue J, Zhang Y, Chen N, Chin YE. Roles of Mitochondrial Serine Hydroxymethyltransferase 2 (SHMT2) in Human Carcinogenesis. J Cancer 2021; 12:5888-5894. [PMID: 34476002 PMCID: PMC8408114 DOI: 10.7150/jca.60170] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 07/26/2021] [Indexed: 11/09/2022] Open
Abstract
In the last few years, cellular metabolic reprogramming has been acknowledged as a hallmark of human cancer and evaluated for its crucial role in supporting the proliferation and survival of human cancer cells. In a variety of human tumours, including hepatocellular carcinoma (HCC), breast cancer and non-small-cell lung cancer (NSCLC), a large amount of carbon is reused in serine/glycine biosynthesis, accompanied by higher expression of the key glycine synthetic enzyme mitochondrial serine hydroxymethyltransferase 2 (SHMT2). This enzyme can convert serine into glycine and a tetrahydrofolate-bound one-carbon unit, ultimately supporting thymidine synthesis and purine synthesis and promoting tumour growth. In tumour samples, elevated expression of SHMT2 was found to be associated with poor prognosis. In this review, the pivotal roles of SHMT2 in human carcinogenesis are described, highlighting the underlying regulatory mechanisms through promotion of tumour progression. In conclusion, SHMT2 may serve as a prognostic marker and a target for anticancer therapies.
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Affiliation(s)
- Yuanyuan Zeng
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, Jiangsu, China.,Department of Respiratory Medicine, the First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu, China
| | - Jie Zhang
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, Jiangsu, China
| | - Mengmeng Xu
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, Jiangsu, China
| | - Fuxian Chen
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, Jiangsu, China
| | - Ruidong Zi
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, Jiangsu, China
| | - Jicheng Yue
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, Jiangsu, China
| | - Yanan Zhang
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, Jiangsu, China
| | - Nannan Chen
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, Jiangsu, China
| | - Y Eugene Chin
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, Jiangsu, China
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Metformin Is a Pyridoxal-5'-phosphate (PLP)-Competitive Inhibitor of SHMT2. Cancers (Basel) 2021; 13:cancers13164009. [PMID: 34439169 PMCID: PMC8393646 DOI: 10.3390/cancers13164009] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/18/2021] [Accepted: 08/05/2021] [Indexed: 02/06/2023] Open
Abstract
Simple Summary The mitochondrial enzyme serine hydroxymethyltransferase (SHMT2), which converts serine into glycine and generates 1C units for cell growth, is one of the most consistently overexpressed metabolic enzymes in cancer. Here, we reveal that the anti-diabetic biguanide metformin operates as a novel class of non-catalytic SHMT2 inhibitor that disrupts the pyridoxal-5′-phosphate (PLP)-dependent SHMT2 oligomerization process and ultimately SHMT2 activity. As SHMT2 inhibitors have not yet reached the clinic, these findings may aid the rational design of PLP-competitive SHMT2 inhibitors based on the biguanide skeleton of metformin. Abstract The anticancer actions of the biguanide metformin involve the functioning of the serine/glycine one-carbon metabolic network. We report that metformin directly and specifically targets the enzymatic activity of mitochondrial serine hydroxymethyltransferase (SHMT2). In vitro competitive binding assays with human recombinant SHMT1 and SHMT2 isoforms revealed that metformin preferentially inhibits SHMT2 activity by a non-catalytic mechanism. Computational docking coupled with molecular dynamics simulation predicted that metformin could occupy the cofactor pyridoxal-5′-phosphate (PLP) cavity and destabilize the formation of catalytically active SHMT2 oligomers. Differential scanning fluorimetry-based biophysical screening confirmed that metformin diminishes the capacity of PLP to promote the conversion of SHMT2 from an inactive, open state to a highly ordered, catalytically competent closed state. CRISPR/Cas9-based disruption of SHMT2, but not of SHMT1, prevented metformin from inhibiting total SHMT activity in cancer cell lines. Isotope tracing studies in SHMT1 knock-out cells confirmed that metformin decreased the SHMT2-channeled serine-to-formate flux and restricted the formate utilization in thymidylate synthesis upon overexpression of the metformin-unresponsive yeast equivalent of mitochondrial complex I (mCI). While maintaining its capacity to inhibit mitochondrial oxidative phosphorylation, metformin lost its cytotoxic and antiproliferative activity in SHMT2-null cancer cells unable to produce energy-rich NADH or FADH2 molecules from tricarboxylic acid cycle (TCA) metabolites. As currently available SHMT2 inhibitors have not yet reached the clinic, our current data establishing the structural and mechanistic bases of metformin as a small-molecule, PLP-competitive inhibitor of the SHMT2 activating oligomerization should benefit future discovery of biguanide skeleton-based novel SHMT2 inhibitors in cancer prevention and treatment.
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11
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Bortolus R, Filippini F, Udali S, Rinaldi M, Genesini S, Gandini G, Montagnana M, Chiaffarino F, Lippi G, Pattini P, De Grandi G, Olivieri O, Parazzini F, Friso S. B vitamin blood concentrations and one-carbon metabolism polymorphisms in a sample of Italian women and men attending a unit of transfusion medicine: a cross-sectional study. Eur J Nutr 2021; 60:2643-2654. [PMID: 33373019 PMCID: PMC8275535 DOI: 10.1007/s00394-020-02448-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 11/24/2020] [Indexed: 11/08/2022]
Abstract
PURPOSE To define blood status of folate, vitamin B12, vitamin B6, homocysteine, and major one-carbon metabolism-related polymorphisms in healthy, males and females blood donors, aged 18-65 years were evaluated. General characteristics and lifestyle factors were also investigated. METHODS An explorative cross-sectional study design was used to evaluate a sample of blood donors attending the Unit of Transfusion Medicine of the Verona University Hospital, Italy. From April 2016 to May 2018, 499 subjects were enrolled (255 men, 244 women of whom 155 of childbearing age). Major clinical characteristics including lifestyle and dietary habits, B vitamins and homocysteine were analyzed. The MTHFR 677 C>T, cSHMT 1420 C>T, DHFR 19 bp ins/del, RFC1 80 G>A polymorphisms were also determined. RESULTS Mean plasma concentrations of folate, vitamin B12, vitamin B6 and homocysteine were 14.2 nmol/L (95% CI 13.7-14.8), 271.9 pmol/L (95% CI 262.6-281.5), 51.0 nmol/L (95% CI 48.7-53.4) and 13.5 µmol/L (95% CI 13.1-14.0), respectively. Plasma folate, was adequate (> 15 nmol/L) in 44.7% of all subjects, 39.0% of males and 42.5% of women < 45 years. Similarly, vitamin B12 was adequate (> 350 pmol/L) in 25.1% of all subjects and in 20.3% of men ≥ 45 years. The rare allele frequencies were 0.21 for MTHFR 677TT, 0.11 for cSHMT 1420TT, 0.18 for DHFR 19 bp del/del, 0.20 for RFC1 80AA, and a gene-nutrient interaction was confirmed for folate concentrations according to MTHFR 677C>T and DHFR 19 bp del/del. CONCLUSION An Italian sample of healthy blood donors shows that an adequate concentration of plasma folate and vitamin B12 is reached only in a limited percentage of subjects, thus encouraging consideration for specific public health strategies.
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Affiliation(s)
- Renata Bortolus
- Office for Research Promotion, Verona University Hospital, Verona, Italy
| | | | - Silvia Udali
- Unit of Internal Medicine, Department of Medicine, University of Verona School of Medicine, Verona, Italy
| | - Marianna Rinaldi
- Unit of Transfusion Medicine, Verona University Hospital, Verona, Italy
| | - Sabrina Genesini
- Unit of Transfusion Medicine, Verona University Hospital, Verona, Italy
| | - Giorgio Gandini
- Unit of Transfusion Medicine, Verona University Hospital, Verona, Italy
| | - Martina Montagnana
- Section of Clinical Biochemistry and Hematology, Verona University Hospital, Verona, Italy
| | - Francesca Chiaffarino
- Department of Woman, Newborn and Child, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Giuseppe Lippi
- Section of Clinical Biochemistry and Hematology, Verona University Hospital, Verona, Italy
| | - Patrizia Pattini
- Unit of Internal Medicine, Department of Medicine, University of Verona School of Medicine, Verona, Italy
| | - Gelinda De Grandi
- Unit of Internal Medicine, Department of Medicine, University of Verona School of Medicine, Verona, Italy
| | - Oliviero Olivieri
- Unit of Internal Medicine, Department of Medicine, University of Verona School of Medicine, Verona, Italy
| | - Fabio Parazzini
- Department of Woman, Newborn and Child, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Department of Clinical Sciences and Community Health, Università Degli Studi di Milano, Milan, Italy
| | - Simonetta Friso
- Unit of Internal Medicine, Department of Medicine, University of Verona School of Medicine, Verona, Italy.
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12
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Zhao LN, Björklund M, Caldez MJ, Zheng J, Kaldis P. Therapeutic targeting of the mitochondrial one-carbon pathway: perspectives, pitfalls, and potential. Oncogene 2021; 40:2339-2354. [PMID: 33664451 DOI: 10.1038/s41388-021-01695-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/27/2021] [Accepted: 02/02/2021] [Indexed: 02/07/2023]
Abstract
Most of the drugs currently prescribed for cancer treatment are riddled with substantial side effects. In order to develop more effective and specific strategies to treat cancer, it is of importance to understand the biology of drug targets, particularly the newly emerging ones. A comprehensive evaluation of these targets will benefit drug development with increased likelihood for success in clinical trials. The folate-mediated one-carbon (1C) metabolism pathway has drawn renewed attention as it is often hyperactivated in cancer and inhibition of this pathway displays promise in developing anticancer treatment with fewer side effects. Here, we systematically review individual enzymes in the 1C pathway and their compartmentalization to mitochondria and cytosol. Based on these insight, we conclude that (1) except the known 1C targets (DHFR, GART, and TYMS), MTHFD2 emerges as good drug target, especially for treating hematopoietic cancers such as CLL, AML, and T-cell lymphoma; (2) SHMT2 and MTHFD1L are potential drug targets; and (3) MTHFD2L and ALDH1L2 should not be considered as drug targets. We highlight MTHFD2 as an excellent therapeutic target and SHMT2 as a complementary target based on structural/biochemical considerations and up-to-date inhibitor development, which underscores the perspectives of their therapeutic potential.
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Affiliation(s)
- Li Na Zhao
- Department of Clinical Sciences, Lund University, Malmö, Sweden.
| | - Mikael Björklund
- Zhejiang University-University of Edinburgh (ZJU-UoE) Institute, Haining, Zhejiang, PR China.,2nd Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, PR China.,Deanery of Biomedical Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, UK
| | - Matias J Caldez
- Laboratory of Host Defense, The World Premier International Research Center Initiative (WPI) Immunology Frontier Research Center (IFReC), Osaka University, Osaka, Japan
| | - Jie Zheng
- School of Information Science and Technology, Shanghai Tech University, Shanghai, PR China
| | - Philipp Kaldis
- Department of Clinical Sciences, Lund University, Malmö, Sweden.
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13
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Tang X, Liu H, Shi Z, Chen Q, Kang X, Wang Y, Zhao P. Enhanced silk yield in transgenic silkworm (Bombyx mori) via ectopic expression of BmGT1-L in the posterior silk gland. INSECT MOLECULAR BIOLOGY 2020; 29:452-465. [PMID: 32654295 DOI: 10.1111/imb.12655] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/11/2020] [Accepted: 06/30/2020] [Indexed: 06/11/2023]
Abstract
The silkworm is an economically important insect producing plentiful silk fibre in the silk gland. In this study, we reported a cross-talk between the fat body, silk gland and midgut through a glycine-serine biosynthetic pathway in the silkworm. Amino acid sequence and functional domains of glycine transporter gene BmGT1-L were mapped. Our results indicated that BmGT1-L was specifically expressed in the midgut microvilli and persistently expressed during the feeding stages. RNA interference of BmGT1-L activated glycine biosynthesis, and BmGT1-L overexpression facilitated serine biosynthesis in the BmN4-SID1 cell. In addition, silkworms after FibH gene knock-out or silk gland extirpation showed markedly decreased BmGT1-L transcripts in the midgut and disturbed glycine-serine biosynthesis as silk yield decreased. Finally, BmGT1-L ectopic expression in the posterior silk gland promoted glycine biosynthesis, and enhanced silk yield via increasing fibroin synthesis. These results suggested that cross-talk between tissues can be used for enhancing silk yield in the silkworm.
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Affiliation(s)
- X Tang
- Biological Science Research Center, Southwest University, Chongqing, China
| | - H Liu
- Biological Science Research Center, Southwest University, Chongqing, China
| | - Z Shi
- Biological Science Research Center, Southwest University, Chongqing, China
| | - Q Chen
- Department of Biochemistry and Molecular Biology, Chongqing Medical University, Chongqing, China
| | - X Kang
- College of Biotechnology, Southwest University, Chongqing, China
| | - Y Wang
- College of Biotechnology, Southwest University, Chongqing, China
| | - P Zhao
- Biological Science Research Center, Southwest University, Chongqing, China
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14
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Xiu Y, Field MS. The Roles of Mitochondrial Folate Metabolism in Supporting Mitochondrial DNA Synthesis, Oxidative Phosphorylation, and Cellular Function. Curr Dev Nutr 2020; 4:nzaa153. [PMID: 33134792 PMCID: PMC7584446 DOI: 10.1093/cdn/nzaa153] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/21/2020] [Accepted: 09/23/2020] [Indexed: 12/21/2022] Open
Abstract
Folate-mediated one-carbon metabolism (FOCM) is compartmentalized within human cells to the cytosol, nucleus, and mitochondria. The recent identifications of mitochondria-specific, folate-dependent thymidylate [deoxythymidine monophosphate (dTMP)] synthesis together with discoveries indicating the critical role of mitochondrial FOCM in cancer progression have renewed interest in understanding this metabolic pathway. The goal of this narrative review is to summarize recent advances in the field of one-carbon metabolism, with an emphasis on the biological importance of mitochondrial FOCM in maintaining mitochondrial DNA integrity and mitochondrial function, as well as the reprogramming of mitochondrial FOCM in cancer. Elucidation of the roles and regulation of mitochondrial FOCM will contribute to a better understanding of the mechanisms underlying folate-associated pathologies.
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Affiliation(s)
- Yuwen Xiu
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Martha S Field
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
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15
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SHMT inhibition is effective and synergizes with methotrexate in T-cell acute lymphoblastic leukemia. Leukemia 2020; 35:377-388. [PMID: 32382081 PMCID: PMC7647950 DOI: 10.1038/s41375-020-0845-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 04/09/2020] [Accepted: 04/22/2020] [Indexed: 12/18/2022]
Abstract
Folate metabolism enables cell growth by providing one-carbon (1C) units for nucleotide biosynthesis. The 1C units are carried by tetrahydrofolate (THF), whose production by the enzyme DHFR is targeted by the important anticancer drug methotrexate. 1C units come largely from serine catabolism by the enzyme SHMT, whose mitochondrial isoform is strongly upregulated in cancer. Here we report the SHMT inhibitor SHIN2 and demonstrate its in vivo target engagement with 13C-serine tracing. As methotrexate is standard treatment for T-cell acute lymphoblastic leukemia (T-ALL), we explored the utility of SHIN2 in this disease. SHIN2 increases survival in NOTCH1-driven mouse primary T-ALL in vivo. Low dose methotrexate sensitizes Molt4 human T-ALL cells to SHIN2, and cells rendered methotrexate resistant in vitro show enhanced sensitivity to SHIN2. Finally, SHIN2 and methotrexate synergize in mouse primary T-ALL and in a human patient-derived xenograft in vivo, increasing survival. Thus, SHMT inhibition offers a complementary strategy in the treatment of T-ALL.
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16
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Brosnan ME, Tingley G, MacMillan L, Harnett B, Pongnopparat T, Marshall JD, Brosnan JT. Plasma Formate Is Greater in Fetal and Neonatal Rats Compared with Their Mothers. J Nutr 2020; 150:1068-1075. [PMID: 31912134 PMCID: PMC7198295 DOI: 10.1093/jn/nxz329] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 09/05/2019] [Accepted: 12/09/2019] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Formate can be incorporated into 10-formyl-tetrahydrofolate (10-formyl-THF), which is a substrate for purine synthesis, and after further reduction of the one-carbon group, may be used as a substrate for thymidylate synthesis and for homocysteine remethylation. OBJECTIVE We examined plasma formate concentrations and the expression of genes involved in the production and utilization of formate in fetal and neonatal rats and in pregnant and virgin female rats. METHODS In 1 experiment, plasma formate was measured by GC-MS in rats aged 1-56 d. In a second experiment, virgin female (adult) rats, 19-d pregnant rats (P) and their male and female fetuses (F), and 3-d-old (N) and 7-d-old (J) offspring had plasma and amniotic fluid analyzed for formate by GC-MS, mRNA abundance in liver and placenta by qPCR, and several plasma amino acids by HPLC. RESULTS The plasma formate concentration was significantly higher in fetuses at embryonic day 19 than in the mothers. It was also significantly higher in neonatal rats but slowly returned to adult concentrations by ∼3 wk. The abundance of mitochondrial monofunctional 10-formyl-tetrahydrofolate synthetase (Mthfd1l) mRNA was significantly higher in placenta (PP) and F liver than in liver of N or J. Expression of mitochondrial bifunctional NAD-dependent methylene-tetrahydrofolate dehydrogenase/methenyl-tetrahydrofolate cyclohydrolase (Mthfd2) was significantly enriched in PP and liver of P, intermediate in F liver, and much lower in liver of N and J, relative to PP. Serine hydroxymethyltransferase 2 (Shmt2), methylenetetrahydrofolate dehydrogenase 1 (Mthfd1), and glycine decarboxylase protein of the glycine cleavage system (Gldc) mRNA expression was significantly lower in PP compared with other groups. Cytoplasmic NAD(P)-dependent 10-formyl-tetrahydrofolate dehydrogenase (Aldh1/1) and mitochondrial NAD(P)-dependent 10-formyl-tetrahydrofolate dehydrogenase (Aldh1/2) , genes responsible for the catabolism of 10-formylTHF, were very weakly expressed in PP, low in livers of F and N, and reached the significantly higher adult levels in J. Serine, glycine, and methionine concentrations in plasma of F were significantly higher than in plasma of P. CONCLUSIONS Formate metabolism is highly active in fetuses and in placenta of pregnant rats.
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Affiliation(s)
- Margaret E Brosnan
- Department of Biochemistry, Memorial University of Newfoundland, St Johns, Newfoundland, Canada,Address correspondence to MEB (e-mail: )
| | - Garrett Tingley
- Department of Biochemistry, Memorial University of Newfoundland, St Johns, Newfoundland, Canada
| | - Luke MacMillan
- Department of Biochemistry, Memorial University of Newfoundland, St Johns, Newfoundland, Canada
| | - Brian Harnett
- Department of Biochemistry, Memorial University of Newfoundland, St Johns, Newfoundland, Canada
| | - Theerawat Pongnopparat
- Department of Biochemistry, Memorial University of Newfoundland, St Johns, Newfoundland, Canada
| | - Jenika D Marshall
- Department of Biochemistry, Memorial University of Newfoundland, St Johns, Newfoundland, Canada
| | - John T Brosnan
- Department of Biochemistry, Memorial University of Newfoundland, St Johns, Newfoundland, Canada
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17
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Dunstan RH, Macdonald MM, Thorn B, Wood D, Roberts TK. Modelling of amino acid turnover in the horse during training and racing: A basis for developing a novel supplementation strategy. PLoS One 2020; 15:e0226988. [PMID: 31899789 PMCID: PMC6941815 DOI: 10.1371/journal.pone.0226988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 12/09/2019] [Indexed: 12/03/2022] Open
Abstract
Horses in heavy training in preparation for racing and competition have increased metabolic demands to support the more intensive levels of exercise and recovery. However, little is known at the metabolic level about amino acid turnover and the specific alterations of demand caused by high intensity exercise. During exercise, certain amino acids are required in greater quantities due to disproportionate losses via excretory systems and usage in biosynthetic pathways. This investigation has built a theoretical computer model in an attempt to bring together the published rates of protein intake and utilisation to try to understand how some amino acids might be in higher demand than others. The model indicated that after evaluation of the daily amino acid turnover, glutamine/glutamic acid (Glx), serine and ornithine were in negative nitrogen balance which identified these amino acids as critical limiting factors for anabolism. Adjustment of the modelling conditions to cater for high intensity training indicated that an additional demand was placed on eight amino acids, including GLx, valine, lysine, histidine and phenylalanine which could thus become limiting under these conditions. The modelling results indicated that an amino acid supplement with the correct amino acids to match demand could theoretically be beneficial to a 500Kg horse in quantities of 20-80g/day. These results open new avenues of research for specifically tailoring amino acid supplementation to meet demands for sports horses in heavy training and improving general well-being, especially in hotter climates.
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Affiliation(s)
- R. Hugh Dunstan
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Australia
| | - Margaret M. Macdonald
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Australia
| | - Brittany Thorn
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Australia
| | - David Wood
- Horsepower Pty Ltd, Windsor, NSW, Australia
| | - Timothy K. Roberts
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Australia
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18
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Guiducci G, Paone A, Tramonti A, Giardina G, Rinaldo S, Bouzidi A, Magnifico MC, Marani M, Menendez JA, Fatica A, Macone A, Armaos A, Tartaglia GG, Contestabile R, Paiardini A, Cutruzzolà F. The moonlighting RNA-binding activity of cytosolic serine hydroxymethyltransferase contributes to control compartmentalization of serine metabolism. Nucleic Acids Res 2019; 47:4240-4254. [PMID: 30809670 PMCID: PMC6486632 DOI: 10.1093/nar/gkz129] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 02/01/2019] [Accepted: 02/15/2019] [Indexed: 12/30/2022] Open
Abstract
Enzymes of intermediary metabolism are often reported to have moonlighting functions as RNA-binding proteins and have regulatory roles beyond their primary activities. Human serine hydroxymethyltransferase (SHMT) is essential for the one-carbon metabolism, which sustains growth and proliferation in normal and tumour cells. Here, we characterize the RNA-binding function of cytosolic SHMT (SHMT1) in vitro and using cancer cell models. We show that SHMT1 controls the expression of its mitochondrial counterpart (SHMT2) by binding to the 5'untranslated region of the SHMT2 transcript (UTR2). Importantly, binding to RNA is modulated by metabolites in vitro and the formation of the SHMT1-UTR2 complex inhibits the serine cleavage activity of the SHMT1, without affecting the reverse reaction. Transfection of UTR2 in cancer cells controls SHMT1 activity and reduces cell viability. We propose a novel mechanism of SHMT regulation, which interconnects RNA and metabolites levels to control the cross-talk between cytosolic and mitochondrial compartments of serine metabolism.
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Affiliation(s)
- Giulia Guiducci
- Department of Biochemical Sciences, Sapienza University of Rome - P. le Aldo Moro 5, 00185 Rome, Italy
| | - Alessio Paone
- Department of Biochemical Sciences, Sapienza University of Rome - P. le Aldo Moro 5, 00185 Rome, Italy
| | - Angela Tramonti
- Department of Biochemical Sciences, Sapienza University of Rome - P. le Aldo Moro 5, 00185 Rome, Italy.,Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, 00185 Rome, Italy
| | - Giorgio Giardina
- Department of Biochemical Sciences, Sapienza University of Rome - P. le Aldo Moro 5, 00185 Rome, Italy
| | - Serena Rinaldo
- Department of Biochemical Sciences, Sapienza University of Rome - P. le Aldo Moro 5, 00185 Rome, Italy
| | - Amani Bouzidi
- Department of Biochemical Sciences, Sapienza University of Rome - P. le Aldo Moro 5, 00185 Rome, Italy
| | - Maria C Magnifico
- Department of Biochemical Sciences, Sapienza University of Rome - P. le Aldo Moro 5, 00185 Rome, Italy
| | - Marina Marani
- Department of Biochemical Sciences, Sapienza University of Rome - P. le Aldo Moro 5, 00185 Rome, Italy
| | - Javier A Menendez
- Program Against Cancer Therapeutic Resistance (ProCURE), Metabolism and Cancer Group, Catalan Institute of Oncology, 17007 Girona, Catalonia, Spain.,Molecular Oncology Group, Girona Biomedical Research Institute (IDIBGI), 17190 Girona, Spain
| | - Alessandro Fatica
- Department of Biology and Biotechnology 'C. Darwin', Sapienza University of Rome, 00185 Rome, Italy
| | - Alberto Macone
- Department of Biochemical Sciences, Sapienza University of Rome - P. le Aldo Moro 5, 00185 Rome, Italy
| | - Alexandros Armaos
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Gian G Tartaglia
- Department of Biology and Biotechnology 'C. Darwin', Sapienza University of Rome, 00185 Rome, Italy.,Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Department of Experimental and Health Sciences, 08003 Barcelona, Spain.,Institucio Catalana de Recerca i Estudis Avançats (ICREA), Department of Life and Medical Sciences, 23 Passeig Lluıs Companys, 08010 Barcelona, Spain
| | - Roberto Contestabile
- Department of Biochemical Sciences, Sapienza University of Rome - P. le Aldo Moro 5, 00185 Rome, Italy
| | - Alessandro Paiardini
- Department of Biochemical Sciences, Sapienza University of Rome - P. le Aldo Moro 5, 00185 Rome, Italy
| | - Francesca Cutruzzolà
- Department of Biochemical Sciences, Sapienza University of Rome - P. le Aldo Moro 5, 00185 Rome, Italy
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19
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Haque MR, Hirowatari A, Nai N, Furuya S, Yamamoto K. Serine hydroxymethyltransferase from the silkworm Bombyx mori: Identification, distribution, and biochemical characterization. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2019; 102:e21594. [PMID: 31298425 DOI: 10.1002/arch.21594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Serine hydroxymethyltransferase (SHMT) catalyzes the interconversion of serine and tetrahydrofolate (THF) to glycine and methylenetetrahydrofolate. cDNA encoding Bombyx mori SHMT (bmSHMT) was cloned and sequenced. The deduced amino acid sequence consisted of 465 amino acids and was found to share homology with other SHMTs. Recombinant bmSHMT was overexpressed in Escherichia coli and purified to homogeneity. The enzyme showed optimum activity at pH 3.0 and 30°C and was stable under acidic conditions. The Km and kcat /Km values for THF in the presence of Nicotinamide adenine dinucleotide phosphate (NADP+ ) were 0.055 mM and 0.081 mM-1 s-1 , respectively, whereas those toward NADP+ were 0.16 mM and 0.018 mM-1 s-1 and toward l-serine were 1.8 mM and 0.0022 mM-1 s-1 , respectively. Mutagenesis experiments revealed that His119, His132, and His135 are important for enzymatic activity. Our results provide insight into the roles and regulation mechanism of one-carbon metabolism in the silkworm B. mori.
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Affiliation(s)
- Mohammad R Haque
- Department of Bioscience and Biotechnology, Kyushu University Graduate School, Nishi-ku, Fukuoka, Japan
| | - Aiko Hirowatari
- Department of Bioscience and Biotechnology, Kyushu University Graduate School, Nishi-ku, Fukuoka, Japan
| | - Nonoko Nai
- Department of Bioscience and Biotechnology, Kyushu University Graduate School, Nishi-ku, Fukuoka, Japan
| | - Shigeki Furuya
- Department of Bioscience and Biotechnology, Kyushu University Graduate School, Nishi-ku, Fukuoka, Japan
| | - Kohji Yamamoto
- Department of Bioscience and Biotechnology, Kyushu University Graduate School, Nishi-ku, Fukuoka, Japan
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20
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Gkiouli M, Biechl P, Eisenreich W, Otto AM. Diverse Roads Taken by 13C-Glucose-Derived Metabolites in Breast Cancer Cells Exposed to Limiting Glucose and Glutamine Conditions. Cells 2019; 8:cells8101113. [PMID: 31547005 PMCID: PMC6829299 DOI: 10.3390/cells8101113] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 09/09/2019] [Accepted: 09/18/2019] [Indexed: 12/20/2022] Open
Abstract
In cancers, tumor cells are exposed to fluctuating nutrient microenvironments with limiting supplies of glucose and glutamine. While the metabolic program has been related to the expression of oncogenes, only fractional information is available on how variable precarious nutrient concentrations modulate the cellular levels of metabolites and their metabolic pathways. We thus sought to obtain an overview of the metabolic routes taken by 13C-glucose-derived metabolites in breast cancer MCF-7 cells growing in combinations of limiting glucose and glutamine concentrations. Isotopologue profiles of key metabolites were obtained by gas chromatography/mass spectrometry (GC/MS). They revealed that in limiting and standard saturating medium conditions, the same metabolic routes were engaged, including glycolysis, gluconeogenesis, as well as the TCA cycle with glutamine and pyruvate anaplerosis. However, the cellular levels of 13C-metabolites, for example, serine, alanine, glutamate, malate, and aspartate, were highly sensitive to the available concentrations and the ratios of glucose and glutamine. Notably, intracellular lactate concentrations did not reflect the Warburg effect. Also, isotopologue profiles of 13C-serine as well as 13C-alanine show that the same glucose-derived metabolites are involved in gluconeogenesis and pyruvate replenishment. Thus, anaplerosis and the bidirectional flow of central metabolic pathways ensure metabolic plasticity for adjusting to precarious nutrient conditions.
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Affiliation(s)
- Maria Gkiouli
- Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany.
| | - Philipp Biechl
- Munich School of BioEngineering, and Department of Chemistry, Chair of Biochemistry, Technical University of Munich, 85748 Garching, Germany.
| | - Wolfgang Eisenreich
- Department of Chemistry, Chair of Biochemistry, Technical University of Munich, 85748 Garching, Germany.
| | - Angela M Otto
- Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany.
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21
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Alptekin A, Ye B, Yu Y, Poole CJ, van Riggelen J, Zha Y, Ding HF. Glycine decarboxylase is a transcriptional target of MYCN required for neuroblastoma cell proliferation and tumorigenicity. Oncogene 2019; 38:7504-7520. [PMID: 31444411 PMCID: PMC6908766 DOI: 10.1038/s41388-019-0967-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 08/05/2019] [Accepted: 08/09/2019] [Indexed: 12/12/2022]
Abstract
Genomic amplification of the oncogene MYCN is a major driver in the development of high-risk neuroblastoma, a pediatric cancer with poor prognosis. Given the challenge in targeting MYCN directly for therapy, we sought to identify MYCN-dependent metabolic vulnerabilities that can be targeted therapeutically. Here, we report that the gene encoding glycine decarboxylase (GLDC), which catalyzes the first and rate-limiting step in glycine breakdown with the production of the one-carbon unit 5,10-methylene-tetrahydrofolate, is a direct transcriptional target of MYCN. As a result, GLDC expression is markedly elevated in MYCN-amplified neuroblastoma tumors and cell lines. This transcriptional upregulation of GLDC expression is of functional significance, as GLDC depletion by RNA interference inhibits the proliferation and tumorigenicity of MYCN-amplified neuroblastoma cell lines by inducing G1 arrest. Metabolomic profiling reveals that GLDC knockdown disrupts purine and central carbon metabolism and reduces citrate production, leading to a decrease in the steady-state levels of cholesterol and fatty acids. Moreover, blocking purine or cholesterol synthesis recapitulates the growth inhibitory effect of GLDC knockdown. These findings reveal a critical role of GLDC in sustaining the proliferation of neuroblastoma cells with high-level GLDC expression and suggest that MYCN amplification is a biomarker for GLDC-based therapeutic strategies against high-risk neuroblastoma.
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Affiliation(s)
- Ahmet Alptekin
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.,Georgia Cancer Center, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Bingwei Ye
- Georgia Cancer Center, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Yajie Yu
- Institute of Neural Regeneration and Repair and Department of Neurology, The First Hospital of Yichang, Three Gorges University College of Medicine, 443000, Yichang, China
| | - Candace J Poole
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.,Georgia Cancer Center, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Jan van Riggelen
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.,Georgia Cancer Center, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Yunhong Zha
- Institute of Neural Regeneration and Repair and Department of Neurology, The First Hospital of Yichang, Three Gorges University College of Medicine, 443000, Yichang, China
| | - Han-Fei Ding
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA. .,Georgia Cancer Center, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA. .,Department of Pathology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.
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22
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Ubonprasert S, Jaroensuk J, Pornthanakasem W, Kamonsutthipaijit N, Wongpituk P, Mee-Udorn P, Rungrotmongkol T, Ketchart O, Chitnumsub P, Leartsakulpanich U, Chaiyen P, Maenpuen S. A flap motif in human serine hydroxymethyltransferase is important for structural stabilization, ligand binding, and control of product release. J Biol Chem 2019; 294:10490-10502. [PMID: 31118236 DOI: 10.1074/jbc.ra119.007454] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 05/21/2019] [Indexed: 12/13/2022] Open
Abstract
Human cytosolic serine hydroxymethyltransferase (hcSHMT) is a promising target for anticancer chemotherapy and contains a flexible "flap motif" whose function is yet unknown. Here, using size-exclusion chromatography, analytical ultracentrifugation, small-angle X-ray scattering (SAXS), molecular dynamics (MD) simulations, and ligand-binding and enzyme-kinetic analyses, we studied the functional roles of the flap motif by comparing WT hcSHMT with a flap-deleted variant (hcSHMT/Δflap). We found that deletion of the flap results in a mixture of apo-dimers and holo-tetramers, whereas the WT was mostly in the tetrameric form. MD simulations indicated that the flap stabilizes structural compactness and thereby enhances oligomerization. The hcSHMT/Δflap variant exhibited different catalytic properties in (6S)-tetrahydrofolate (THF)-dependent reactions compared with the WT but had similar activity in THF-independent aldol cleavage of β-hydroxyamino acid. hcSHMT/Δflap was less sensitive to THF inhibition than the WT (Ki of 0.65 and 0.27 mm THF at pH 7.5, respectively), and the THF dissociation constant of the WT was also 3-fold lower than that of hcSHMT/Δflap, indicating that the flap is important for THF binding. hcSHMT/Δflap did not display the burst kinetics observed in the WT. These results indicate that, upon removal of the flap, product release is no longer the rate-limiting step, implying that the flap is important for controlling product release. The findings reported here improve our understanding of the functional roles of the flap motif in hcSHMT and provide fundamental insight into how a flexible loop can be involved in controlling the enzymatic reactions of hcSHMT and other enzymes.
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Affiliation(s)
- Sakunrat Ubonprasert
- From the Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Juthamas Jaroensuk
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong 21210, Thailand
| | - Wichai Pornthanakasem
- Biomolecular Analysis and Application Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), and
| | | | - Peerapong Wongpituk
- Center of Excellence in Computational Chemistry (CECC), Department of Chemistry, and
| | - Pitchayathida Mee-Udorn
- Bioinformatics and Computational Biology Program, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand, and
| | - Thanyada Rungrotmongkol
- Bioinformatics and Computational Biology Program, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand, and.,Biocatalyst and Environmental Biotechnology Research Unit, Department of Biochemistry, Faculty of Science, and
| | - Onuma Ketchart
- National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency, Pathumthani 12120, Thailand
| | - Penchit Chitnumsub
- Biomolecular Analysis and Application Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), and
| | - Ubolsree Leartsakulpanich
- Biomolecular Analysis and Application Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), and
| | - Pimchai Chaiyen
- From the Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.,School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong 21210, Thailand
| | - Somchart Maenpuen
- Department of Biochemistry, Faculty of Science, Burapha University, Chonburi 20131, Thailand
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23
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Modelling of protein turnover provides insight for metabolic demands on those specific amino acids utilised at disproportionately faster rates than other amino acids. Amino Acids 2019; 51:945-959. [PMID: 31028564 DOI: 10.1007/s00726-019-02734-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 04/09/2019] [Indexed: 10/26/2022]
Abstract
The nitrogen balance is regulated by factors such as diet, physical activity, age, pathogenic challenges, and climatic conditions. A paradigm was developed from published recommended rates of protein intake (g/kg/day) with corresponding rates of endogenous protein turnover and excretion, to extrapolate amino acid balances under various conditions. The average proportions of amino acids in the ingested proteins representing a well-balanced diet were used to assess intake and an average human composition profile from five major high-turnover proteins in the body to assess endogenous protein turnover. The amino acid excretion profiles for urine and sweat were constructed for males and females from published data. The model calculated the nitrogen balances for a range of amino acids to determine the amino acid requirements to support daily exertion. Histidine, serine, glycine, and ornithine were in negative balances in males and females and this potential deficit was greater in the higher body-mass ranges. Conversely, leucine, isoleucine, and valine were conserved during nitrogen flux and resulted in positive balances. The model was run under a scenario of high demand for the synthesis of IgG during a response to an infectious challenge which indicated that these were increased requirements for tyrosine, threonine, and valine. It was concluded that these amino acids represent points of limitation to anabolic metabolism by restriction of their supply at critical times of demand. This would especially occur under conditions of fitness training, maintaining intensive exercise regimes, facilitating responses to pathogenic challenge, or recovery from injury.
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24
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Sodolescu A, Dian C, Terradot L, Bouzhir-Sima L, Lestini R, Myllykallio H, Skouloubris S, Liebl U. Structural and functional insight into serine hydroxymethyltransferase from Helicobacter pylori. PLoS One 2018; 13:e0208850. [PMID: 30550583 PMCID: PMC6294363 DOI: 10.1371/journal.pone.0208850] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 11/23/2018] [Indexed: 11/19/2022] Open
Abstract
Serine hydroxymethyltransferase (SHMT), encoded by the glyA gene, is a ubiquitous pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the formation of glycine from serine. The thereby generated 5,10-methylene tetrahydrofolate (MTHF) is a major source of cellular one-carbon units and a key intermediate in thymidylate biosynthesis. While in virtually all eukaryotic and many bacterial systems thymidylate synthase ThyA, SHMT and dihydrofolate reductase (DHFR) are part of the thymidylate/folate cycle, the situation is different in organisms using flavin-dependent thymidylate synthase ThyX. Here the distinct catalytic reaction directly produces tetrahydrofolate (THF) and consequently in most ThyX-containing organisms, DHFR is absent. While the resulting influence on the folate metabolism of ThyX-containing bacteria is not fully understood, the presence of ThyX may provide growth benefits under conditions where the level of reduced folate derivatives is compromised. Interestingly, the third key enzyme implicated in generation of MTHF, serine hydroxymethyltransferase (SHMT), has a universal phylogenetic distribution, but remains understudied in ThyX-containg bacteria. To obtain functional insight into these ThyX-dependent thymidylate/folate cycles, we characterized the predicted SHMT from the ThyX-containing bacterium Helicobacter pylori. Serine hydroxymethyltransferase activity was confirmed by functional genetic complementation of a glyA-inactivated E. coli strain. A H. pylori ΔglyA strain was obtained, but exhibited markedly slowed growth and had lost the virulence factor CagA. Biochemical and spectroscopic evidence indicated formation of a characteristic enzyme-PLP-glycine-folate complex and revealed unexpectedly weak binding affinity of PLP. The three-dimensional structure of the H. pylori SHMT apoprotein was determined at 2.8Ǻ resolution, suggesting a structural basis for the low affinity of the enzyme for its cofactor. Stabilization of the proposed inactive configuration using small molecules has potential to provide a specific way for inhibiting HpSHMT.
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Affiliation(s)
- Andreea Sodolescu
- Laboratory of Optics and Biosciences, Ecole polytechnique, CNRS, INSERM, Université Paris Saclay, Palaiseau, France
| | - Cyril Dian
- Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris Saclay, Gif-sur-Yvette, France
| | - Laurent Terradot
- UMR 5086 Molecular Microbiology and Structural Biochemistry, Institut de Biologie et Chimie des Protéines, CNRS, Université de Lyon, Lyon, France
| | - Latifa Bouzhir-Sima
- Laboratory of Optics and Biosciences, Ecole polytechnique, CNRS, INSERM, Université Paris Saclay, Palaiseau, France
| | - Roxane Lestini
- Laboratory of Optics and Biosciences, Ecole polytechnique, CNRS, INSERM, Université Paris Saclay, Palaiseau, France
| | - Hannu Myllykallio
- Laboratory of Optics and Biosciences, Ecole polytechnique, CNRS, INSERM, Université Paris Saclay, Palaiseau, France
| | - Stéphane Skouloubris
- Laboratory of Optics and Biosciences, Ecole polytechnique, CNRS, INSERM, Université Paris Saclay, Palaiseau, France
- Department of Biology, Université Paris-Sud, Université Paris Saclay, Orsay, France
| | - Ursula Liebl
- Laboratory of Optics and Biosciences, Ecole polytechnique, CNRS, INSERM, Université Paris Saclay, Palaiseau, France
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25
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Sweeny EA, Singh AB, Chakravarti R, Martinez-Guzman O, Saini A, Haque MM, Garee G, Dans PD, Hannibal L, Reddi AR, Stuehr DJ. Glyceraldehyde-3-phosphate dehydrogenase is a chaperone that allocates labile heme in cells. J Biol Chem 2018; 293:14557-14568. [PMID: 30012884 DOI: 10.1074/jbc.ra118.004169] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 07/05/2018] [Indexed: 11/06/2022] Open
Abstract
Cellular heme is thought to be distributed between a pool of sequestered heme that is tightly bound within hemeproteins and a labile heme pool required for signaling and transfer into proteins. A heme chaperone that can hold and allocate labile heme within cells has long been proposed but never been identified. Here, we show that the glycolytic protein glyceraldehyde-3-phosphate dehydrogenase (GAPDH) fulfills this role by acting as an essential repository and allocator of bioavailable heme to downstream protein targets. We identified a conserved histidine in GAPDH that is needed for its robust heme binding both in vitro and in mammalian cells. Substitution of this histidine, and the consequent decreases in GAPDH heme binding, antagonized heme delivery to both cytosolic and nuclear hemeprotein targets, including inducible nitric-oxide synthase (iNOS) in murine macrophages and the nuclear transcription factor Hap1 in yeast, even though this GAPDH variant caused cellular levels of labile heme to rise dramatically. We conclude that by virtue of its heme-binding property, GAPDH binds and chaperones labile heme to create a heme pool that is bioavailable to downstream proteins. Our finding solves a fundamental question in cell biology and provides a new foundation for exploring heme homeostasis in health and disease.
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Affiliation(s)
- Elizabeth A Sweeny
- From the Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195
| | - Anuradha Bharara Singh
- From the Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195
| | - Ritu Chakravarti
- From the Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195
| | - Osiris Martinez-Guzman
- the School of Chemistry and Biochemistry and Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Arushi Saini
- the School of Chemistry and Biochemistry and Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Mohammad Mahfuzul Haque
- From the Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195
| | - Greer Garee
- From the Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195
| | - Pablo D Dans
- the Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology, Balidiri Reixac 10-12, Barcelona 08028, Spain, and
| | - Luciana Hannibal
- the Laboratory of Clinical Biochemistry and Metabolism, Center of Pediatrics, Medical Center, University of Freiburg, D-79106 Freiburg, Germany
| | - Amit R Reddi
- the School of Chemistry and Biochemistry and Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Dennis J Stuehr
- From the Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195,
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26
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Lan X, Field MS, Stover PJ. Cell cycle regulation of folate-mediated one-carbon metabolism. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2018; 10:e1426. [DOI: 10.1002/wsbm.1426] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 04/26/2018] [Accepted: 04/27/2018] [Indexed: 12/25/2022]
Affiliation(s)
- Xu Lan
- Division of Nutritional Sciences; Cornell University; Ithaca New York
| | - Martha S. Field
- Division of Nutritional Sciences; Cornell University; Ithaca New York
| | - Patrick J. Stover
- Division of Nutritional Sciences; Cornell University; Ithaca New York
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27
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Lucas S, Chen G, Aras S, Wang J. Serine catabolism is essential to maintain mitochondrial respiration in mammalian cells. Life Sci Alliance 2018; 1:e201800036. [PMID: 30456347 PMCID: PMC6238390 DOI: 10.26508/lsa.201800036] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 05/07/2018] [Accepted: 05/08/2018] [Indexed: 01/17/2023] Open
Abstract
Mitochondrial respiratory complex assembly requires the one-carbon unit generated from serine catabolism. Breakdown of serine by the enzyme serine hydroxymethyltransferase (SHMT) produces glycine and one-carbon (1C) units. These serine catabolites provide important metabolic intermediates for the synthesis of nucleotides, as well as methyl groups for biosynthetic and regulatory methylation reactions. Recently, it has been shown that serine catabolism is required for efficient cellular respiration. Using CRISPR-Cas9 gene editing, we demonstrate that the mitochondrial SHMT enzyme, SHMT2, is essential to maintain cellular respiration, the main process through which mammalian cells acquire energy. We show that SHMT2 is required for the assembly of Complex I of the respiratory chain. Furthermore, supplementation of formate, a bona fide 1C donor, restores Complex I assembly in the absence of SHMT2. Thus, provision of 1C units by mitochondrial serine catabolism is critical for cellular respiration, at least in part by influencing the assembly of the respiratory apparatus.
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Affiliation(s)
- Stephanie Lucas
- Department of Pathology, Wayne State University, Detroit, MI, USA
| | - Guohua Chen
- Department of Pathology, Wayne State University, Detroit, MI, USA
| | - Siddhesh Aras
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI, USA
| | - Jian Wang
- Department of Pathology, Wayne State University, Detroit, MI, USA.,Cardiovascular Research Institute, Wayne State University, Detroit, MI, USA
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28
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Adeva-Andany M, Souto-Adeva G, Ameneiros-Rodríguez E, Fernández-Fernández C, Donapetry-García C, Domínguez-Montero A. Insulin resistance and glycine metabolism in humans. Amino Acids 2017; 50:11-27. [PMID: 29094215 DOI: 10.1007/s00726-017-2508-0] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 10/27/2017] [Indexed: 12/27/2022]
Abstract
Plasma glycine level is low in patients with obesity or diabetes and the improvement of insulin resistance increases plasma glycine concentration. In prospective studies, hypoglycinemia at baseline predicts the risk of developing type 2 diabetes and higher serum glycine level is associated with decreased risk of incident type 2 diabetes. Consistently, plasma glycine concentration is lower in the lean offspring of parents with type 2 diabetes compared to healthy subjects. Among patients with type 2 diabetes, hypoglycinemia occurs before clinical manifestations of the disease, but the pathophysiological mechanisms underlying glycine deficit and its potential clinical repercussions are unclear. Glycine participates in several metabolic pathways, being required for relevant human physiological processes. Humans synthesize glycine from glyoxylate, glucose (via serine), betaine and likely from threonine and during the endogenous synthesis of L-carnitine. Glycine conjugates bile acids and other acyl moieties producing acyl-glycine derivatives. The glycine cleavage system catalyzes glycine degradation to carbon dioxide and ammonium while tetrahydrofolate is converted into 5,10-methylene-tetrahydrofolate. Glycine is utilized to synthesize serine, sarcosine, purines, creatine, heme group, glutathione, and collagen. Glycine is a major quantitative component of collagen. In addition, the role of glycine maintaining collagen structure is critical, as glycine residues are required to stabilize the triple helix of the collagen molecule. This quality of glycine likely contributes to explain the occurrence of medial arterial calcification and the elevated cardiovascular risk associated with diabetes and chronic kidney disease, as emerging evidence links normal collagen content with the initiation and progression of vascular calcification in humans.
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Affiliation(s)
- M Adeva-Andany
- Internal Medicine Department, Hospital General Juan Cardona, c/Pardo Bazán s/n, 15406, Ferrol, Spain.
| | - G Souto-Adeva
- National Institutes of Health, National Institute of Arthritis and Metabolic Diseases, Bethesda, USA
| | - E Ameneiros-Rodríguez
- Internal Medicine Department, Hospital General Juan Cardona, c/Pardo Bazán s/n, 15406, Ferrol, Spain
| | - C Fernández-Fernández
- Internal Medicine Department, Hospital General Juan Cardona, c/Pardo Bazán s/n, 15406, Ferrol, Spain
| | - C Donapetry-García
- Internal Medicine Department, Hospital General Juan Cardona, c/Pardo Bazán s/n, 15406, Ferrol, Spain
| | - A Domínguez-Montero
- Internal Medicine Department, Hospital General Juan Cardona, c/Pardo Bazán s/n, 15406, Ferrol, Spain
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29
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Abstract
Protein modification with the small ubiquitin-related modifier (SUMO) can affect protein function, enzyme activity, protein-protein interactions, protein stability, protein targeting and cellular localization. SUMO influences the function and regulation of metabolic enzymes within pathways, and in some cases targets entire metabolic pathways by affecting the activity of transcription factors or by facilitating the translocation of entire metabolic pathways to subcellular compartments. SUMO modification is also a key component of nutrient- and metabolic-sensing mechanisms that regulate cellular metabolism. In addition to its established roles in maintaining metabolic homeostasis, there is increasing evidence that SUMO is a key factor in facilitating cellular stress responses through the regulation and/or adaptation of the most fundamental metabolic processes, including energy and nucleotide metabolism. This review focuses on the role of SUMO in cellular metabolism and metabolic disease.
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30
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Multifarious Beneficial Effect of Nonessential Amino Acid, Glycine: A Review. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:1716701. [PMID: 28337245 PMCID: PMC5350494 DOI: 10.1155/2017/1716701] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 02/07/2017] [Accepted: 02/07/2017] [Indexed: 02/06/2023]
Abstract
Glycine is most important and simple, nonessential amino acid in humans, animals, and many mammals. Generally, glycine is synthesized from choline, serine, hydroxyproline, and threonine through interorgan metabolism in which kidneys and liver are the primarily involved. Generally in common feeding conditions, glycine is not sufficiently synthesized in humans, animals, and birds. Glycine acts as precursor for several key metabolites of low molecular weight such as creatine, glutathione, haem, purines, and porphyrins. Glycine is very effective in improving the health and supports the growth and well-being of humans and animals. There are overwhelming reports supporting the role of supplementary glycine in prevention of many diseases and disorders including cancer. Dietary supplementation of proper dose of glycine is effectual in treating metabolic disorders in patients with cardiovascular diseases, several inflammatory diseases, obesity, cancers, and diabetes. Glycine also has the property to enhance the quality of sleep and neurological functions. In this review we will focus on the metabolism of glycine in humans and animals and the recent findings and advances about the beneficial effects and protection of glycine in different disease states.
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31
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Marani M, Paone A, Fiascarelli A, Macone A, Gargano M, Rinaldo S, Giardina G, Pontecorvi V, Koes D, McDermott L, Yang T, Paiardini A, Contestabile R, Cutruzzolà F. A pyrazolopyran derivative preferentially inhibits the activity of human cytosolic serine hydroxymethyltransferase and induces cell death in lung cancer cells. Oncotarget 2016; 7:4570-83. [PMID: 26717037 PMCID: PMC4826227 DOI: 10.18632/oncotarget.6726] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 11/25/2015] [Indexed: 01/25/2023] Open
Abstract
Serine hydroxymethyltransferase (SHMT) is a central enzyme in the metabolic reprogramming of cancer cells, providing activated one-carbon units in the serine-glycine one-carbon metabolism. Previous studies demonstrated that the cytoplasmic isoform of SHMT (SHMT1) plays a relevant role in lung cancer. SHMT1 is overexpressed in lung cancer patients and NSCLC cell lines. Moreover, SHMT1 is required to maintain DNA integrity. Depletion in lung cancer cell lines causes cell cycle arrest and uracil accumulation and ultimately leads to apoptosis. We found that a pyrazolopyran compound, namely 2.12, preferentially inhibits SHMT1 compared to the mitochondrial counterpart SHMT2. Computational and crystallographic approaches suggest binding at the active site of SHMT1 and a competitive inhibition mechanism. A radio isotopic activity assay shows that inhibition of SHMT by 2.12 also occurs in living cells. Moreover, administration of 2.12 in A549 and H1299 lung cancer cell lines causes apoptosis at LD50 34 μM and rescue experiments underlined selectivity towards SHMT1. These data not only further highlight the relevance of the cytoplasmic isoform SHMT1 in lung cancer but, more importantly, demonstrate that, at least in vitro, it is possible to find selective inhibitors against one specific isoform of SHMT, a key target in metabolic reprogramming of many cancer types.
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Affiliation(s)
- Marina Marani
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome 00185, Italy
| | - Alessio Paone
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome 00185, Italy
| | - Alessio Fiascarelli
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome 00185, Italy
| | - Alberto Macone
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome 00185, Italy
| | - Maurizio Gargano
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome 00185, Italy
| | - Serena Rinaldo
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome 00185, Italy
| | - Giorgio Giardina
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome 00185, Italy
| | - Valentino Pontecorvi
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome 00185, Italy
| | - David Koes
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Lee McDermott
- Department of Pharmaceutical Sciences and Drug Discovery Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Tianyi Yang
- Department of Chemistry and Biochemistry Cristol 63, University of Colorado, Boulder, CO 80302, USA
| | - Alessandro Paiardini
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome 00185, Italy
| | - Roberto Contestabile
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome 00185, Italy
| | - Francesca Cutruzzolà
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome 00185, Italy
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32
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Ducker GS, Chen L, Morscher RJ, Ghergurovich JM, Esposito M, Teng X, Kang Y, Rabinowitz JD. Reversal of Cytosolic One-Carbon Flux Compensates for Loss of the Mitochondrial Folate Pathway. Cell Metab 2016; 23:1140-1153. [PMID: 27211901 PMCID: PMC4909566 DOI: 10.1016/j.cmet.2016.04.016] [Citation(s) in RCA: 244] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 02/11/2016] [Accepted: 04/22/2016] [Indexed: 01/29/2023]
Abstract
One-carbon (1C) units for purine and thymidine synthesis can be generated from serine by cytosolic or mitochondrial folate metabolism. The mitochondrial 1C pathway is consistently overexpressed in cancer. Here, we show that most but not all proliferating mammalian cell lines use the mitochondrial pathway as the default for making 1C units. Clustered regularly interspaced short palindromic repeats (CRISPR)-mediated mitochondrial pathway knockout activates cytosolic 1C-unit production. This reversal in cytosolic flux is triggered by depletion of a single metabolite, 10-formyl-tetrahydrofolate (10-formyl-THF), and enables rapid cell growth in nutrient-replete conditions. Loss of the mitochondrial pathway, however, renders cells dependent on extracellular serine to make 1C units and on extracellular glycine to make glutathione. HCT-116 colon cancer xenografts lacking mitochondrial 1C pathway activity generate the 1C units required for growth by cytosolic serine catabolism. Loss of both pathways precludes xenograft formation. Thus, either mitochondrial or cytosolic 1C metabolism can support tumorigenesis, with the mitochondrial pathway required in nutrient-poor conditions.
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Affiliation(s)
- Gregory S Ducker
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Li Chen
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Raphael J Morscher
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Research Program in Receptor Biochemistry and Tumor Metabolism, Paracelsus Medical University, 5020 Salzburg, Austria; Division of Medical Genetics, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Jonathan M Ghergurovich
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Mark Esposito
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Xin Teng
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Yibin Kang
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Joshua D Rabinowitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
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33
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SHMT1 knockdown induces apoptosis in lung cancer cells by causing uracil misincorporation. Cell Death Dis 2014; 5:e1525. [PMID: 25412303 PMCID: PMC4260740 DOI: 10.1038/cddis.2014.482] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 10/03/2014] [Accepted: 10/09/2014] [Indexed: 12/15/2022]
Abstract
Reprogramming of cellular metabolism towards de novo serine production fuels the growth of cancer cells, providing essential precursors such as amino acids and nucleotides and controlling the antioxidant and methylation capacities of the cell. The enzyme serine hydroxymethyltransferase (SHMT) has a key role in this metabolic shift, and directs serine carbons to one-carbon units metabolism and thymidilate synthesis. While the mitochondrial isoform of SHMT (SHMT2) has recently been identified as an important player in the control of cell proliferation in several cancer types and as a hot target for anticancer therapies, the role of the cytoplasmic isoform (SHMT1) in cancerogenesis is currently less defined. In this paper we show that SHMT1 is overexpressed in tissue samples from lung cancer patients and lung cancer cell lines, suggesting that, in this widespread type of tumor, SHMT1 plays a relevant role. We show that SHMT1 knockdown in lung cancer cells leads to cell cycle arrest and, more importantly, to p53-dependent apoptosis. Our data demonstrate that the induction of apoptosis does not depend on serine or glycine starvation, but is because of the increased uracil accumulation during DNA replication.
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Field MS, Kamynina E, Agunloye OC, Liebenthal RP, Lamarre SG, Brosnan ME, Brosnan JT, Stover PJ. Nuclear enrichment of folate cofactors and methylenetetrahydrofolate dehydrogenase 1 (MTHFD1) protect de novo thymidylate biosynthesis during folate deficiency. J Biol Chem 2014; 289:29642-50. [PMID: 25213861 DOI: 10.1074/jbc.m114.599589] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Folate-mediated one-carbon metabolism is a metabolic network of interconnected pathways that is required for the de novo synthesis of three of the four DNA bases and the remethylation of homocysteine to methionine. Previous studies have indicated that the thymidylate synthesis and homocysteine remethylation pathways compete for a limiting pool of methylenetetrahydrofolate cofactors and that thymidylate biosynthesis is preserved in folate deficiency at the expense of homocysteine remethylation, but the mechanisms are unknown. Recently, it was shown that thymidylate synthesis occurs in the nucleus, whereas homocysteine remethylation occurs in the cytosol. In this study we demonstrate that methylenetetrahydrofolate dehydrogenase 1 (MTHFD1), an enzyme that generates methylenetetrahydrofolate from formate, ATP, and NADPH, functions in the nucleus to support de novo thymidylate biosynthesis. MTHFD1 translocates to the nucleus in S-phase MCF-7 and HeLa cells. During folate deficiency mouse liver MTHFD1 levels are enriched in the nucleus >2-fold at the expense of levels in the cytosol. Furthermore, nuclear folate levels are resistant to folate depletion when total cellular folate levels are reduced by >50% in mouse liver. The enrichment of folate cofactors and MTHFD1 protein in the nucleus during folate deficiency in mouse liver and human cell lines accounts for previous metabolic studies that indicated 5,10-methylenetetrahydrofolate is preferentially directed toward de novo thymidylate biosynthesis at the expense of homocysteine remethylation during folate deficiency.
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Affiliation(s)
- Martha S Field
- From the Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853 and
| | - Elena Kamynina
- From the Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853 and
| | | | - Rebecca P Liebenthal
- From the Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853 and
| | - Simon G Lamarre
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X9, Canada
| | - Margaret E Brosnan
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X9, Canada
| | - John T Brosnan
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X9, Canada
| | - Patrick J Stover
- From the Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853 and
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The histone H3 methyltransferase G9A epigenetically activates the serine-glycine synthesis pathway to sustain cancer cell survival and proliferation. Cell Metab 2013; 18:896-907. [PMID: 24315373 PMCID: PMC3878056 DOI: 10.1016/j.cmet.2013.11.004] [Citation(s) in RCA: 168] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 08/30/2013] [Accepted: 10/16/2013] [Indexed: 12/13/2022]
Abstract
Increased activation of the serine-glycine biosynthetic pathway is an integral part of cancer metabolism that drives macromolecule synthesis needed for cell proliferation. Whether this pathway is under epigenetic control is unknown. Here we show that the histone H3 lysine 9 (H3K9) methyltransferase G9A is required for maintaining the pathway enzyme genes in an active state marked by H3K9 monomethylation and for the transcriptional activation of this pathway in response to serine deprivation. G9A inactivation depletes serine and its downstream metabolites, triggering cell death with autophagy in cancer cell lines of different tissue origins. Higher G9A expression, which is observed in various cancers and is associated with greater mortality in cancer patients, increases serine production and enhances the proliferation and tumorigenicity of cancer cells. These findings identify a G9A-dependent epigenetic program in the control of cancer metabolism, providing a rationale for G9A inhibition as a therapeutic strategy for cancer.
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Parker CC, Sokoloff G, Leung E, Kirkpatrick SL, Palmer AA. A large QTL for fear and anxiety mapped using an F2 cross can be dissected into multiple smaller QTLs. GENES BRAIN AND BEHAVIOR 2013; 12:714-22. [PMID: 23876074 DOI: 10.1111/gbb.12064] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 06/24/2013] [Accepted: 07/18/2013] [Indexed: 11/26/2022]
Abstract
Using chromosome substitution strains (CSS), we previously identified a large quantitative trait locus (QTL) for conditioned fear (CF) on mouse chromosome 10. Here, we used an F2 cross between CSS-10 and C57BL/6J (B6) to localize that QTL to distal chromosome 10. That QTL accounted for all the difference between CSS-10 and B6. We then produced congenic strains to fine-map that interval. We identified two congenic strains that captured some or all the QTL. The larger congenic strain (Line 1: 122.387121-129.068 Mb; build 37) appeared to account for all the difference between CSS-10 and B6. The smaller congenic strain (Line 2: 127.277-129.068 Mb) was intermediate between CSS-10 and B6. We used haplotype mapping followed by quantitative polymerase chain reaction to identify one gene that was differentially expressed in both lines relative to B6 (Rnf41) and one that was differentially expressed between only Line 1 and B6 (Shmt2). These cis-eQTLs may cause the behavioral QTLs; however, further studies are required to validate these candidate genes. More generally, our observation that a large QTL mapped using CSS and F2 crosses can be dissected into multiple smaller QTLs shows a weaknesses of two-stage approaches that seek to use coarse mapping to identify large regions followed by fine-mapping. Indeed, additional dissection of these congenic strains might result in further subdivision of these QTL regions. Despite these limitations, we have successfully fine-mapped two QTLs to small regions and identified putative candidate genes, showing that the congenic approach can be effective for fine-mapping QTLs.
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Lee JCY, Tsoi A, Kornfeld GD, Dawes IW. Cellular responses toL-serine inSaccharomyces cerevisiae: roles of general amino acid control, compartmentalization, and aspartate synthesis. FEMS Yeast Res 2013; 13:618-34. [DOI: 10.1111/1567-1364.12063] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 07/02/2013] [Accepted: 07/02/2013] [Indexed: 11/29/2022] Open
Affiliation(s)
- Johnny C.-Y. Lee
- Ramaciotti Center for Gene Function Analysis and School of Biotechnology and Biomolecular Sciences; University of New South Wales; Sydney; NSW; Australia
| | - Abraham Tsoi
- Ramaciotti Center for Gene Function Analysis and School of Biotechnology and Biomolecular Sciences; University of New South Wales; Sydney; NSW; Australia
| | - Geoffrey D. Kornfeld
- Ramaciotti Center for Gene Function Analysis and School of Biotechnology and Biomolecular Sciences; University of New South Wales; Sydney; NSW; Australia
| | - Ian W. Dawes
- Ramaciotti Center for Gene Function Analysis and School of Biotechnology and Biomolecular Sciences; University of New South Wales; Sydney; NSW; Australia
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Li Q, Lambrechts MJ, Zhang Q, Liu S, Ge D, Yin R, Xi M, You Z. Glyphosate and AMPA inhibit cancer cell growth through inhibiting intracellular glycine synthesis. Drug Des Devel Ther 2013; 7:635-43. [PMID: 23983455 PMCID: PMC3749059 DOI: 10.2147/dddt.s49197] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Glycine is a nonessential amino acid that is reversibly converted from serine intracellularly by serine hydroxymethyltransferase. Glyphosate and its degradation product, aminomethylphosphonic acid (AMPA), are analogs to glycine, thus they may inhibit serine hydroxymethyltransferase to decrease intracellular glycine synthesis. In this study, we found that glyphosate and AMPA inhibited cell growth in eight human cancer cell lines but not in two immortalized human normal prostatic epithelial cell lines. AMPA arrested C4-2B and PC-3 cancer cells in the G1/G0 phase and inhibited entry into the S phase of the cell cycle. AMPA also promoted apoptosis in C4-2B and PC-3 cancer cell lines. AMPA upregulated p53 and p21 protein levels as well as procaspase 9 protein levels in C4-2B cells, whereas it downregulated cyclin D3 protein levels. AMPA also activated caspase 3 and induced cleavage of poly (adenosine diphosphate [ADP]-ribose) polymerase. This study provides the first evidence that glyphosate and AMPA can inhibit proliferation and promote apoptosis of cancer cells but not normal cells, suggesting that they have potentials to be developed into a new anticancer therapy.
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Affiliation(s)
- Qingli Li
- Departments of Structural and Cellular Biology and Orthopaedic Surgery, Tulane Cancer Center and Louisiana Cancer Research Consortium, Tulane Center for Stem Cell Research and Regenerative Medicine, and Tulane Center for Aging, Tulane University Health Sciences Center, New Orleans, LA, USA
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, People’s Republic of China
| | - Mark J Lambrechts
- Departments of Structural and Cellular Biology and Orthopaedic Surgery, Tulane Cancer Center and Louisiana Cancer Research Consortium, Tulane Center for Stem Cell Research and Regenerative Medicine, and Tulane Center for Aging, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Qiuyang Zhang
- Departments of Structural and Cellular Biology and Orthopaedic Surgery, Tulane Cancer Center and Louisiana Cancer Research Consortium, Tulane Center for Stem Cell Research and Regenerative Medicine, and Tulane Center for Aging, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Sen Liu
- Departments of Structural and Cellular Biology and Orthopaedic Surgery, Tulane Cancer Center and Louisiana Cancer Research Consortium, Tulane Center for Stem Cell Research and Regenerative Medicine, and Tulane Center for Aging, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Dongxia Ge
- Departments of Structural and Cellular Biology and Orthopaedic Surgery, Tulane Cancer Center and Louisiana Cancer Research Consortium, Tulane Center for Stem Cell Research and Regenerative Medicine, and Tulane Center for Aging, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Rutie Yin
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, People’s Republic of China
| | - Mingrong Xi
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, People’s Republic of China
| | - Zongbing You
- Departments of Structural and Cellular Biology and Orthopaedic Surgery, Tulane Cancer Center and Louisiana Cancer Research Consortium, Tulane Center for Stem Cell Research and Regenerative Medicine, and Tulane Center for Aging, Tulane University Health Sciences Center, New Orleans, LA, USA
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Abstract
Vitamin B6 functions as a coenzyme in >140 enzymatic reactions involved in the metabolism of amino acids, carbohydrates, neurotransmitters, and lipids. It comprises a group of three related 3-hydroxy-2-methyl-pyrimidine derivatives: pyridoxine (PN), pyridoxal (PL), pyridoxamine (PM) and their phosphorylated derivatives [pyridoxal 5'-phosphate (PLP) and pyridoxamine 5'-phosphate (PMP)], In the folate metabolism pathway, PLP is a cofactor for the mitochondrial and cytoplasmic isozymes of serine hydroxymethyltransferase (SHMT2 and SHMT1), the P-protein of the glycine cleavage system, cystathionine β-synthase (CBS) and γ-cystathionase, and betaine hydroxymethyltransferase (BHMT), all of which contribute to homocysteine metabolism either through folate- mediated one-carbon metabolism or the transsulfuration pathway. Folate cofactors carry and chemically activate single carbons for the synthesis of purines, thymidylate and methionine. So the evidence indicates that vitamin B6 plays an important role in maintenance of the genome, epigenetic stability and homocysteine metabolism. This article focuses on studies of strand breaks, micronuclei, or chromosomal aberrations regarding protective effects of vitamin B6, and probes whether it is folate-mediated one-carbon metabolism or the transsulfuration pathway for vitamin B6 which plays critical roles in prevention of cancer and cardiovascular disease.
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Affiliation(s)
- Xia-Yu Wu
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming, China.
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Glycine metabolism in animals and humans: implications for nutrition and health. Amino Acids 2013; 45:463-77. [PMID: 23615880 DOI: 10.1007/s00726-013-1493-1] [Citation(s) in RCA: 432] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 04/02/2013] [Indexed: 01/01/2023]
Abstract
Glycine is a major amino acid in mammals and other animals. It is synthesized from serine, threonine, choline, and hydroxyproline via inter-organ metabolism involving primarily the liver and kidneys. Under normal feeding conditions, glycine is not adequately synthesized in birds or in other animals, particularly in a diseased state. Glycine degradation occurs through three pathways: the glycine cleavage system (GCS), serine hydroxymethyltransferase, and conversion to glyoxylate by peroxisomal D-amino acid oxidase. Among these pathways, GCS is the major enzyme to initiate glycine degradation to form ammonia and CO2 in animals. In addition, glycine is utilized for the biosynthesis of glutathione, heme, creatine, nucleic acids, and uric acid. Furthermore, glycine is a significant component of bile acids secreted into the lumen of the small intestine that is necessary for the digestion of dietary fat and the absorption of long-chain fatty acids. Glycine plays an important role in metabolic regulation, anti-oxidative reactions, and neurological function. Thus, this nutrient has been used to: (1) prevent tissue injury; (2) enhance anti-oxidative capacity; (3) promote protein synthesis and wound healing; (4) improve immunity; and (5) treat metabolic disorders in obesity, diabetes, cardiovascular disease, ischemia-reperfusion injuries, cancers, and various inflammatory diseases. These multiple beneficial effects of glycine, coupled with its insufficient de novo synthesis, support the notion that it is a conditionally essential and also a functional amino acid for mammals (including pigs and humans).
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41
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Cordeiro OD, Silva TS, Alves RN, Costas B, Wulff T, Richard N, de Vareilles M, Conceição LEC, Rodrigues PM. Changes in liver proteome expression of Senegalese sole (Solea senegalensis) in response to repeated handling stress. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2012; 14:714-729. [PMID: 22327442 DOI: 10.1007/s10126-012-9437-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 01/16/2012] [Indexed: 05/28/2023]
Abstract
The Senegalese sole, a high-value flatfish, is a good candidate for aquaculture production. Nevertheless, there are still issues regarding this species' sensitivity to stress in captivity. We aimed to characterize the hepatic proteome expression for this species in response to repeated handling and identify potential molecular markers that indicate a physiological response to chronic stress. Two groups of fish were reared in duplicate for 28 days, one of them weekly exposed to handling stress (including hypoxia) for 3 min, and the other left undisturbed. Two-dimensional electrophoresis enabled the detection of 287 spots significantly affected by repeated handling stress (Wilcoxon-Mann-Whitney U test, p < 0.05), 33 of which could be reliably identified by peptide mass spectrometry. Chronic exposure to stress seems to have affected protein synthesis, folding and turnover (40S ribosomal protein S12, cathepsin B, disulfide-isomerase A3 precursor, cell-division cycle 48, and five distinct heat shock proteins), amino acid metabolism, urea cycle and methylation/folate pathways (methionine adenosyltransferase I α, phenylalanine hydroxylase, mitochondrial agmatinase, serine hydroxymethyltransferase, 3-hydroxyanthranilate 3,4-dioxygenase, and betaine homocysteine methyltransferase), cytoskeletal (40S ribosomal protein SA, α-actin, β-actin, α-tubulin, and cytokeratin K18), aldehyde detoxification (aldehyde dehydrogenase 4A1 family and aldehyde dehydrogenase 7A1 family), carbohydrate metabolism and energy homeostasis (fatty acid-binding protein, enolase 3, enolase 1, phosphoglycerate kinase, glyceraldehyde-3-phosphate dehydrogenase, aconitase 1, mitochondrial ATP synthase α-subunit, and electron-transfer flavoprotein α polypeptide), iron and selenium homeostasis (transferrin and selenium binding protein 1), steroid hormone metabolism (3-oxo-5-β-steroid 4-dehydrogenase), and purine salvage (hypoxanthine phosphoribosyltransferase). Further characterization is required to fully assess the potential of these markers for the monitoring of fish stress response to chronic stressors of aquaculture environment.
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Affiliation(s)
- Odete D Cordeiro
- Centro de Ciências do Mar do Algarve, Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
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Abstract
SIGNIFICANCE The progressive, dose-dependent, and potentially reversible epigenetic changes observed in cancer present new opportunities in cancer risk modification and prevention using dietary and lifestyle factors. Folate, a water-soluble B vitamin, has been of intense interest because of an inverse association between folate status and the risk of several malignancies (particularly colorectal cancer) and its potential to modulate DNA methylation. Aberrant patterns and dysregulation of DNA methylation are mechanistically related to carcinogenesis. RECENT ADVANCES The effects of folate on DNA methylation patterns have recently been investigated in two important life stages: pre- and early postnatal life and aging. Recent studies have demonstrated that folate exposure in the intrauterine environment and early life and during the aging process may have profound effects on DNA methylation with significant functional ramifications, including the risk of cancer. CRITICAL ISSUES Evidence from animal, human, and in vitro studies suggest that the epigenetic effects of folate on DNA methylation are highly complex. The effects are gene and site specific and appear to depend on cell type, target organ, stage of transformation, the degree and duration of folate manipulations, interactions with other methyl group donors and dietary factors, and genetic variants in the folate metabolic pathways. FUTURE DIRECTIONS The potential for folate to modulate DNA methylation and, thus, modify the risk of cancer in humans is worthy of further investigation. Due to the complex relationship between folate exposure and DNA methylation, more elaborate epidemiological, clinical, and mechanistic studies that determine the clinical, biological, and molecular effects of folate are warranted.
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Affiliation(s)
- Anna Ly
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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Hebbring SJ, Chai Y, Ji Y, Abo RP, Jenkins GD, Fridley B, Zhang J, Eckloff BW, Wieben ED, Weinshilboum RM. Serine hydroxymethyltransferase 1 and 2: gene sequence variation and functional genomic characterization. J Neurochem 2012; 120:881-90. [PMID: 22220685 DOI: 10.1111/j.1471-4159.2012.07646.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Serine hydroxymethyltransferase (SHMT) catalyzes the transfer of a β-carbon from serine to tetrahydrofolate to form glycine and 5,10-methylene-tetrahydrofolate. This reaction plays an important role in neurotransmitter synthesis and metabolism. We set out to resequence SHMT1 and SHMT2, followed by functional genomic studies. We identified 87 and 60 polymorphisms in SHMT1 and SHMT2, respectively. We observed no significant functional effect of the 13 non-synonymous single-nucleotide polymorphism (SNPs) in these genes, either on catalytic activity or protein quantity. We imputed additional variants across the two genes using '1000 Genomes' data, and identified 14 variants that were significantly associated (p<1.0E-10) with SHMT1 messenger RNA expression in lymphoblastoid cell lines. Many of these SNPs were also significantly correlated with basal SHMT1 protein expression in 268 human liver biopsy samples. Reporter gene assays suggested that the SHMT1 promoter SNP, rs669340, contributed to this variation. Finally, SHMT1 and SHMT2 expression were significantly correlated with those of other Folate and Methionine Cycle genes at both the messenger RNA and protein levels. These experiments represent a comprehensive study of SHMT1 and SHMT2 gene sequence variation and its functional implications. In addition, we obtained preliminary indications that these genes may be co-regulated with other Folate and Methionine Cycle genes.
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Affiliation(s)
- Scott J Hebbring
- Division of Clinical Pharmacology, Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, USA
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Anderson DD, Woeller CF, Chiang EP, Shane B, Stover PJ. Serine hydroxymethyltransferase anchors de novo thymidylate synthesis pathway to nuclear lamina for DNA synthesis. J Biol Chem 2012; 287:7051-62. [PMID: 22235121 DOI: 10.1074/jbc.m111.333120] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The de novo thymidylate biosynthetic pathway in mammalian cells translocates to the nucleus for DNA replication and repair and consists of the enzymes serine hydroxymethyltransferase 1 and 2α (SHMT1 and SHMT2α), thymidylate synthase, and dihydrofolate reductase. In this study, we demonstrate that this pathway forms a multienzyme complex that is associated with the nuclear lamina. SHMT1 or SHMT2α is required for co-localization of dihydrofolate reductase, SHMT, and thymidylate synthase to the nuclear lamina, indicating that SHMT serves as scaffold protein that is essential for complex formation. The metabolic complex is enriched at sites of DNA replication initiation and associated with proliferating cell nuclear antigen and other components of the DNA replication machinery. These data provide a mechanism for previous studies demonstrating that SHMT expression is rate-limiting for de novo thymidylate synthesis and indicate that de novo thymidylate biosynthesis occurs at replication forks.
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Affiliation(s)
- Donald D Anderson
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853, USA
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45
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Wermuth PJ, Addya S, Jimenez SA. Effect of protein kinase C delta (PKC-δ) inhibition on the transcriptome of normal and systemic sclerosis human dermal fibroblasts in vitro. PLoS One 2011; 6:e27110. [PMID: 22096525 PMCID: PMC3214051 DOI: 10.1371/journal.pone.0027110] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 10/10/2011] [Indexed: 12/16/2022] Open
Abstract
Previous studies demonstrated that protein kinase C- δ (PKC-δ) inhibition with the selective inhibitor, rottlerin, resulted in potent downregulation of type I collagen expression and production in normal human dermal fibroblasts and abrogated the exaggerated type I collagen production and expression in fibroblasts cultured from affected skin from patients with the fibrosing disorder systemic sclerosis (SSc). To elucidate the mechanisms involved in the ability of PKC-δ to regulate collagen production in fibroblasts, we examined the effects of PKC-δ inhibition on the transcriptome of normal and SSc human dermal fibroblasts. Normal and SSc human dermal fibroblasts were incubated with rottlerin (5 µM), and their gene expression was analyzed by microarrays. Pathway analysis and gene ontology analysis of differentially expressed genes in each comparison were performed. Identification of significantly overrepresented transcriptional regulatory elements (TREs) was performed using the Promoter Analysis and Interaction Network Toolset (PAINT) program. PKC-δ activity was also inhibited using RNA interference (siRNA) and by treating fibroblasts with a specific PKC-δ inhibitory cell permeable peptide. Differential gene expression of 20 genes was confirmed using real time PCR. PKC-δ inhibition caused a profound change in the transcriptome of normal and SSc human dermal fibroblasts in vitro. Pathway and gene ontology analysis identified multiple cellular and organismal pathways affected by PKC-δ inhibition. Furthermore, both pathway and PAINT analyses indicated that the transcription factor NFκB played an important role in the transcriptome changes induced by PKC-δ inhibition. Multiple genes involved in the degradation of the extracellular matrix components were significantly reduced in SSc fibroblasts and their expression was increased by PKC-δ inhibition. These results indicate that isoform-specific inhibition of PKC-δ profibrotic effects may represent a novel therapeutic approach for SSc and other fibrotic diseases.
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Affiliation(s)
- Peter J. Wermuth
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Sankar Addya
- Kimmel Cancer Center, Department of Cancer Biology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Sergio A. Jimenez
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
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MacFarlane AJ, Anderson DD, Flodby P, Perry CA, Allen RH, Stabler SP, Stover PJ. Nuclear localization of de novo thymidylate biosynthesis pathway is required to prevent uracil accumulation in DNA. J Biol Chem 2011; 286:44015-44022. [PMID: 22057276 DOI: 10.1074/jbc.m111.307629] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Uracil accumulates in DNA as a result of impaired folate-dependent de novo thymidylate biosynthesis, a pathway composed of the enzymes serine hydroxymethyltransferase (SHMT), thymidylate synthase (TYMS), and dihydrofolate reductase. In G1, this pathway is present in the cytoplasm and at S phase undergoes small ubiquitin-like modifier-dependent translocation to the nucleus. It is not known whether this pathway functions in the cytoplasm, nucleus, or both in vivo. SHMT1 generates 5,10-methylenetetrahydrofolate for de novo thymidylate biosynthesis, a limiting step in the pathway, but also tightly binds 5-methyltetrahydrofolate in the cytoplasm, a required cofactor for homocysteine remethylation. Overexpression of SHMT1 in cell cultures inhibits folate-dependent homocysteine remethylation and enhances thymidylate biosynthesis. In this study, the impact of increased Shmt1 expression on folate-mediated one-carbon metabolism was determined in mice that overexpress the Shmt1 cDNA (Shmt1tg+ mice). Compared with wild type mice, Shmt1tg+ mice exhibited elevated SHMT1 and TYMS protein levels in tissues and evidence for impaired homocysteine remethylation but surprisingly exhibited depressed levels of nuclear SHMT1 and TYMS, lower rates of nuclear de novo thymidylate biosynthesis, and a nearly 10-fold increase in uracil content in hepatic nuclear DNA when fed a folate- and choline-deficient diet. These results demonstrate that SHMT1 and TYMS localization to the nucleus is essential to prevent uracil accumulation in nuclear DNA and indicate that SHMT1-mediated nuclear de novo thymidylate synthesis is critical for maintaining DNA integrity.
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Affiliation(s)
- Amanda J MacFarlane
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853
| | - Donald D Anderson
- Graduate Field of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, New York 14853
| | - Per Flodby
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853
| | - Cheryll A Perry
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853
| | - Robert H Allen
- Department of Medicine and Division of Hematology, University of Colorado School of Medicine, Aurora, Colorado 80045
| | - Sally P Stabler
- Department of Medicine and Division of Hematology, University of Colorado School of Medicine, Aurora, Colorado 80045
| | - Patrick J Stover
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853; Graduate Field of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, New York 14853.
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47
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Identification of a de novo thymidylate biosynthesis pathway in mammalian mitochondria. Proc Natl Acad Sci U S A 2011; 108:15163-8. [PMID: 21876188 DOI: 10.1073/pnas.1103623108] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The de novo and salvage dTTP pathways are essential for maintaining cellular dTTP pools to ensure the faithful replication of both mitochondrial and nuclear DNA. Disregulation of dTTP pools results in mitochondrial dysfunction and nuclear genome instability due to an increase in uracil misincorporation. In this study, we identified a de novo dTMP synthesis pathway in mammalian mitochondria. Mitochondria purified from wild-type Chinese hamster ovary (CHO) cells and HepG2 cells converted dUMP to dTMP in the presence of NADPH and serine, through the activities of mitochondrial serine hydroxymethyltransferase (SHMT2), thymidylate synthase (TYMS), and a novel human mitochondrial dihydrofolate reductase (DHFR) previously thought to be a pseudogene known as dihydrofolate reductase-like protein 1 (DHFRL1). Human DHFRL1, SHMT2, and TYMS were localized to mitochondrial matrix and inner membrane, confirming the presence of this pathway in mitochondria. Knockdown of DHFRL1 using siRNA eliminated DHFR activity in mitochondria. DHFRL1 expression in CHO glyC, a previously uncharacterized mutant glycine auxotrophic cell line, rescued the glycine auxotrophy. De novo thymidylate synthesis activity was diminished in mitochondria isolated from glyA CHO cells that lack SHMT2 activity, as well as mitochondria isolated from wild-type CHO cells treated with methotrexate, a DHFR inhibitor. De novo thymidylate synthesis in mitochondria prevents uracil accumulation in mitochondrial DNA (mtDNA), as uracil levels in mtDNA isolated from glyA CHO cells was 40% higher than observed in mtDNA isolated from wild-type CHO cells. These data indicate that unlike other nucleotides, de novo dTMP synthesis occurs within mitochondria and is essential for mtDNA integrity.
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The former annotated human pseudogene dihydrofolate reductase-like 1 (DHFRL1) is expressed and functional. Proc Natl Acad Sci U S A 2011; 108:15157-62. [PMID: 21876184 DOI: 10.1073/pnas.1103605108] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human dihydrofolate reductase (DHFR) was previously thought to be the only enzyme capable of the reduction of dihydrofolate to tetrahydrofolate; an essential reaction necessary to ensure a continuous supply of biologically active folate. DHFR has been studied extensively from a number of perspectives because of its role in health and disease. Although the presence of a number of intronless DHFR pseudogenes has been known since the 1980s, it was assumed that none of these were expressed or functional. We show that humans do have a second dihydrofolate reductase enzyme encoded by the former pseudogene DHFRP4, located on chromosome 3. We demonstrate that the DHFRP4, or dihydrofolate reductase-like 1 (DHFRL1), gene is expressed and shares some commonalities with DHFR. Recombinant DHFRL1 can complement a DHFR-negative phenotype in bacterial and mammalian cells but has a lower specific activity than DHFR. The K(m) for NADPH is similar for both enzymes but DHFRL1 has a higher K(m) for dihydrofolate when compared to DHFR. The need for a second reductase with lowered affinity for its substrate may fulfill a specific cellular requirement. The localization of DHFRL1 to the mitochondria, as demonstrated by confocal microscopy, indicates that mitochondrial dihydrofolate reductase activity may be optimal with a lowered affinity for dihydrofolate. We also found that DHFRL1 is capable of the same translational autoregulation as DHFR by binding to its own mRNA; with each enzyme also capable of replacing the other. The identification of DHFRL1 will have implications for previous research involving DHFR.
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Macfarlane AJ, Perry CA, McEntee MF, Lin DM, Stover PJ. Shmt1 heterozygosity impairs folate-dependent thymidylate synthesis capacity and modifies risk of Apc(min)-mediated intestinal cancer risk. Cancer Res 2011; 71:2098-107. [PMID: 21406397 DOI: 10.1158/0008-5472.can-10-1886] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Folate-mediated one-carbon metabolism is required for the de novo synthesis of purines, thymidylate, and S-adenosylmethionine, the primary cellular methyl donor. Impairments in folate metabolism diminish cellular methylation potential and genome stability, which are risk factors for colorectal cancer (CRC). Cytoplasmic serine hydroxymethyltransferase (SHMT1) regulates the partitioning of folate-activated one-carbons between thymidylate and S-adenosylmethionine biosynthesis. Therefore, changes in SHMT1 expression enable the determination of the specific contributions made by thymidylate and S-adenosylmethionine biosynthesis to CRC risk. Shmt1 hemizygosity was associated with a decreased capacity for thymidylate synthesis due to downregulation of enzymes in its biosynthetic pathway, namely thymidylate synthase and cytoplasmic thymidine kinase. Significant Shmt1-dependent changes to methylation capacity, gene expression, and purine synthesis were not observed. Shmt1 hemizygosity was associated with increased risk for intestinal cancer in Apc(min)(/+) mice through a gene-by-diet interaction, indicating that the capacity for thymidylate synthesis modifies susceptibility to intestinal cancer in Apc(min)(/+) mice.
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Affiliation(s)
- Amanda J Macfarlane
- Division of Nutritional Sciences and Department of Biomedical Sciences, Cornell University, Ithaca, New York 14850, USA
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Labrie V, Wong AHC, Roder JC. Contributions of the D-serine pathway to schizophrenia. Neuropharmacology 2011; 62:1484-503. [PMID: 21295046 DOI: 10.1016/j.neuropharm.2011.01.030] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2010] [Revised: 01/16/2011] [Accepted: 01/19/2011] [Indexed: 01/30/2023]
Abstract
The glutamate neurotransmitter system is one of the major candidate pathways for the pathophysiology of schizophrenia, and increased understanding of the pharmacology, molecular biology and biochemistry of this system may lead to novel treatments. Glutamatergic hypofunction, particularly at the NMDA receptor, has been hypothesized to underlie many of the symptoms of schizophrenia, including psychosis, negative symptoms and cognitive impairment. This review will focus on D-serine, a co-agonist at the NMDA receptor that in combination with glutamate, is required for full activation of this ion channel receptor. Evidence implicating D-serine, NMDA receptors and related molecules, such as D-amino acid oxidase (DAO), G72 and serine racemase (SRR), in the etiology or pathophysiology of schizophrenia is discussed, including knowledge gained from mouse models with altered D-serine pathway genes and from preliminary clinical trials with D-serine itself or compounds modulating the D-serine pathway. Abnormalities in D-serine availability may underlie glutamatergic dysfunction in schizophrenia, and the development of new treatments acting through the D-serine pathway may significantly improve outcomes for many schizophrenia patients.
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Affiliation(s)
- Viviane Labrie
- Krembil Family Epigenetics Laboratory, Centre for Addiction and Mental Health, 250 College St, Toronto, ON M5T 1R8, Canada.
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