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Yan H, Liu W, Xiang R, Li X, Hou S, Xu L, Wang L, Zhao D, Liu X, Wang G, Chi Y, Yang J. Ribosomal modification protein rimK-like family member A activates betaine-homocysteine S-methyltransferase 1 to ameliorate hepatic steatosis. Signal Transduct Target Ther 2024; 9:214. [PMID: 39117631 PMCID: PMC11310345 DOI: 10.1038/s41392-024-01914-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 06/14/2024] [Accepted: 07/04/2024] [Indexed: 08/10/2024] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a serious threat to public health, but its underlying mechanism remains poorly understood. In screening important genes using Gene Importance Calculator (GIC) we developed previously, ribosomal modification protein rimK-like family member A (RIMKLA) was predicted as one essential gene but its functions remained largely unknown. The current study determined the roles of RIMKLA in regulating glucose and lipid metabolism. RIMKLA expression was reduced in livers of human and mouse with NAFLD. Hepatic RIMKLA overexpression ameliorated steatosis and hyperglycemia in obese mice. Hepatocyte-specific RIMKLA knockout aggravated high-fat diet (HFD)-induced dysregulated glucose/lipid metabolism in mice. Mechanistically, RIMKLA is a new protein kinase that phosphorylates betaine-homocysteine S-methyltransferase 1 (BHMT1) at threonine 45 (Thr45) site. Upon phosphorylation at Thr45 and activation, BHMT1 eliminated homocysteine (Hcy) to inhibit the activity of transcription factor activator protein 1 (AP1) and its induction on fatty acid synthase (FASn) and cluster of differentiation 36 (CD36) gene transcriptions, concurrently repressing lipid synthesis and uptake in hepatocytes. Thr45 to alanine (T45A) mutation inactivated BHMT1 to abolish RIMKLA's repression on Hcy level, AP1 activity, FASn/CD36 expressions, and lipid deposition. BHMT1 overexpression rescued the dysregulated lipid metabolism in RIMKLA-deficient hepatocytes. In summary, RIMKLA is a novel protein kinase that phosphorylates BHMT1 at Thr45 to repress lipid synthesis and uptake. Under obese condition, inhibition of RIMKLA impairs BHMT1 activity to promote hepatic lipid deposition.
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Affiliation(s)
- Han Yan
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, State Key Laboratory of Vascular Homeostasis and Remodeling, Center for Non-coding RNA Medicine, Peking University Health Science Center, Beijing, 100191, China
- Department of Endocrinology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Wenjun Liu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, State Key Laboratory of Vascular Homeostasis and Remodeling, Center for Non-coding RNA Medicine, Peking University Health Science Center, Beijing, 100191, China
| | - Rui Xiang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, State Key Laboratory of Vascular Homeostasis and Remodeling, Center for Non-coding RNA Medicine, Peking University Health Science Center, Beijing, 100191, China
| | - Xin Li
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, State Key Laboratory of Vascular Homeostasis and Remodeling, Center for Non-coding RNA Medicine, Peking University Health Science Center, Beijing, 100191, China
| | - Song Hou
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, State Key Laboratory of Vascular Homeostasis and Remodeling, Center for Non-coding RNA Medicine, Peking University Health Science Center, Beijing, 100191, China
| | - Luzheng Xu
- Medical and Health Analysis Center, Peking University, Beijing, 100191, China
| | - Lin Wang
- Department of Hepatobiliary Surgery, Xi-Jing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Dong Zhao
- Department of Endocrinology, Beijing Luhe Hospital, Capital Medical University, Beijing, 101100, China
| | - Xingkai Liu
- Department of Hepatobiliary and Pancreatic Surgery, General Surgery Centre, First Hospital of Jilin University, Changchun, 130061, China.
| | - Guoqing Wang
- Key Laboratory of Pathobiology Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun, 130012, China.
| | - Yujing Chi
- Department of Central Laboratory and Institute of Clinical Molecular Biology, Department of Gastroenterology, Peking University People's Hospital, Beijing, 100044, China.
| | - Jichun Yang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, State Key Laboratory of Vascular Homeostasis and Remodeling, Center for Non-coding RNA Medicine, Peking University Health Science Center, Beijing, 100191, China.
- Department of Cardiology, Peking University Third Hospital, Beijing, 100191, China.
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2
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Grønbæk-Thygesen M, Hartmann-Petersen R. Cellular and molecular mechanisms of aspartoacylase and its role in Canavan disease. Cell Biosci 2024; 14:45. [PMID: 38582917 PMCID: PMC10998430 DOI: 10.1186/s13578-024-01224-6] [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: 12/15/2023] [Accepted: 03/24/2024] [Indexed: 04/08/2024] Open
Abstract
Canavan disease is an autosomal recessive and lethal neurological disorder, characterized by the spongy degeneration of the white matter in the brain. The disease is caused by a deficiency of the cytosolic aspartoacylase (ASPA) enzyme, which catalyzes the hydrolysis of N-acetyl-aspartate (NAA), an abundant brain metabolite, into aspartate and acetate. On the physiological level, the mechanism of pathogenicity remains somewhat obscure, with multiple, not mutually exclusive, suggested hypotheses. At the molecular level, recent studies have shown that most disease linked ASPA gene variants lead to a structural destabilization and subsequent proteasomal degradation of the ASPA protein variants, and accordingly Canavan disease should in general be considered a protein misfolding disorder. Here, we comprehensively summarize the molecular and cell biology of ASPA, with a particular focus on disease-linked gene variants and the pathophysiology of Canavan disease. We highlight the importance of high-throughput technologies and computational prediction tools for making genotype-phenotype predictions as we await the results of ongoing trials with gene therapy for Canavan disease.
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Affiliation(s)
- Martin Grønbæk-Thygesen
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200N, Copenhagen, Denmark.
| | - Rasmus Hartmann-Petersen
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200N, Copenhagen, Denmark.
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3
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Becker I, Wang-Eckhardt L, Eckhardt M. NAAG synthetase deficiency has only low influence on pathogenesis in a Canavan disease mouse model. J Inherit Metab Dis 2024; 47:230-243. [PMID: 38011891 DOI: 10.1002/jimd.12693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 11/14/2023] [Accepted: 11/15/2023] [Indexed: 11/29/2023]
Abstract
Canavan disease (CD) is a leukodystrophy caused by mutations in the N-acetylaspartate (NAA) hydrolase aspartoacylase (ASPA). Inability to degrade NAA and its accumulation in the brain results in spongiform myelin degeneration. NAA is mainly synthesized by neurons, where it is also a precursor of the neuropeptide N-acetylaspartylglutamate (NAAG). Hydrolysis of this peptide by glutamate carboxypeptidases is an additional source of extracellular NAA besides the instant neuronal release of NAA. This study examines to what extent NAA released from NAAG contributes to NAA accumulation and pathogenesis in the brain of Aspanur7/nur7 mutant mice, an established model of CD. Towards this aim, Aspanur7/nur7 mice with additional deficiencies in NAAG synthetase genes Rimklb and/or Rimkla were generated. Loss of myelin in Aspanur7/nur7 mice was not significantly affected by Rimkla and Rimklb deficiency and there was also no obvious change in the extent of brain vacuolation. Astrogliosis was slightly reduced in the forebrain of Rimkla and Rimklb double deficient Aspanur7/nur7 mice. However, only minor improvements at the behavioral level were found. The brain NAA accumulation in CD mice was, however, not significantly reduced in the absence of NAAG synthesis. In summary, there was only a weak tendency towards reduced pathogenic symptoms in Aspanur7/nur7 mice deficient in NAAG synthesis. Therefore, we conclude that NAAG metabolism has little influence on NAA accumulation in Aspanur7/nur7 mice and development of pathological symptoms in CD.
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Affiliation(s)
- Ivonne Becker
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Lihua Wang-Eckhardt
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Matthias Eckhardt
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Bonn, Germany
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4
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Ye C, Cheng F, Huang L, Wang K, Zhong L, Lu Y, Ouyang M. New plasma diagnostic markers for colorectal cancer: transporter fragments of glutamate tRNA origin. J Cancer 2024; 15:1299-1313. [PMID: 38356701 PMCID: PMC10861818 DOI: 10.7150/jca.92102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 01/03/2024] [Indexed: 02/16/2024] Open
Abstract
Colorectal cancer (CRC) is the second leading cause of cancer-related deaths worldwide. Early diagnosis of the disease can greatly improve the clinical prognosis for patients with CRC. Unfortunately, there are no current simple and effective early diagnostic markers available. The transfer RNA (tRNA)-derived RNA fragments (tRFs) are a class of small non-coding RNAs (sncRNAs), which have been shown to play an important role in the development and prognosis of CRC. However, only a few studies on tRFs as early diagnostic markers in CRC have been conducted. In this study, previously ignored tRFs expression data were extracted from six paired small RNA sequencing data in the Sequence Read Archive (SRA) database using MINTmap. Three i-tRFs, derived from the tRNA that transports glutamate (i-tRF-Glu), were identified and used to construct a random forest diagnostic model. The model performance was evaluated using the receiver operating characteristic (ROC) curve and precision-recall (PR) curve. The area under the curves (AUC) for the ROC and PR was 0.941 and 0.944, respectively. We further verified the differences in expression of the these i-tRF-Glu in the tissue and plasma of both CRC patients and healthy subjects using quantitative real-time PCR (qRT-PCR). We found that the ROC-AUC of the three was greater than traditional plasma tumor markers such as CEA and CA199. Our bioinformatics analysis suggested that the these i-tRF-Glu are associated with cancer development and glutamate (Glu)-glutamine (Gln) metabolism. Overall, our study uncovered these i-tRF-Glu that have early diagnostic significance and therapeutic potential for CRC, this warrants further investigation into the diagnostic and therapeutic potential of these i-tRF-Glu in CRC.
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Affiliation(s)
- Changda Ye
- Department of Gastrointestinal Surgery, Shunde Hospital, Southern Medical University (The First People's Hospital of Shunde Foshan), Shunde, Foshan, Guangdong Province, 528300, China
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong Province, 510080, China
| | - Fu Cheng
- Department of Gastrointestinal Surgery, Shunde Hospital, Southern Medical University (The First People's Hospital of Shunde Foshan), Shunde, Foshan, Guangdong Province, 528300, China
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong Province, 510080, China
| | - Luji Huang
- Department of Gastrointestinal Surgery, Shunde Hospital, Southern Medical University (The First People's Hospital of Shunde Foshan), Shunde, Foshan, Guangdong Province, 528300, China
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong Province, 510080, China
| | - Kang Wang
- Department of Gastrointestinal Surgery, Shunde Hospital, Southern Medical University (The First People's Hospital of Shunde Foshan), Shunde, Foshan, Guangdong Province, 528300, China
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong Province, 510080, China
| | - Lin Zhong
- Department of Gastrointestinal Surgery, Shunde Hospital, Southern Medical University (The First People's Hospital of Shunde Foshan), Shunde, Foshan, Guangdong Province, 528300, China
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong Province, 510080, China
| | - Yan Lu
- GCP Center, Shunde Hospital, Southern Medical University (The First People's Hospital of Shunde Foshan), Foshan, 528300, Guangdong, China
| | - Manzhao Ouyang
- Department of Gastrointestinal Surgery, Shunde Hospital, Southern Medical University (The First People's Hospital of Shunde Foshan), Shunde, Foshan, Guangdong Province, 528300, China
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong Province, 510080, China
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5
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Ohnuki J, Arimura Y, Kono T, Kino K, Kurumizaka H, Takano M. Electrostatic Ratchet for Successive Peptide Synthesis in Nonribosomal Molecular Machine RimK. J Am Chem Soc 2023. [PMID: 37452763 PMCID: PMC10375531 DOI: 10.1021/jacs.3c03926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Abstract
A nonribosomal peptide-synthesizing molecular machine, RimK, adds l-glutamic acids to the C-terminus of ribosomal protein S6 (RpsF) in vivo and synthesizes poly-α-glutamates in vitro. However, the mechanism of the successive glutamate addition, which is fueled by ATP, remains unclear. Here, we investigate the successive peptide-synthesizing mechanism of RimK via the molecular dynamics (MD) simulation of glutamate binding. We first show that RimK adopts three stable structural states with respect to the ATP-binding loop and the triphosphate chain of the bound ATP. We then show that a glutamate in solution preferentially binds to a positively charged belt-like region of RimK and the bound glutamate exhibits Brownian motion along the belt. The binding-energy landscape shows that the open-to-closed transition of the ATP-binding loop and the bent-to-straight transition of the triphosphate chain of ATP can function as an electrostatic ratchet that guides the bound glutamate to the active site. We then show the binding site of the second glutamate, which allows us to infer the ligation mechanism. Consistent with MD results, the crystal structure of RimK we obtained in the presence of RpsF presents an electron density that is presumed to correspond to the C-terminus of RpsF. We finally propose a mechanism for the successive peptide synthesis by RimK and discuss its similarity to other molecular machines.
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Affiliation(s)
- Jun Ohnuki
- Department of Pure and Applied Physics, Waseda University, Okubo 3-4-1, Shinjuku-Ku, Tokyo 169-8555, Japan
| | - Yasuhiro Arimura
- Institute for Quantitative Biosciences, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Tomonori Kono
- Department of Applied Chemistry, Waseda University, Okubo 3-4-1, Shinjuku-Ku, Tokyo 169-8555, Japan
| | - Kuniki Kino
- Department of Applied Chemistry, Waseda University, Okubo 3-4-1, Shinjuku-Ku, Tokyo 169-8555, Japan
| | - Hitoshi Kurumizaka
- Institute for Quantitative Biosciences, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Mitsunori Takano
- Department of Pure and Applied Physics, Waseda University, Okubo 3-4-1, Shinjuku-Ku, Tokyo 169-8555, Japan
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6
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Jurdzinski KT, Mehrshad M, Delgado LF, Deng Z, Bertilsson S, Andersson AF. Large-scale phylogenomics of aquatic bacteria reveal molecular mechanisms for adaptation to salinity. SCIENCE ADVANCES 2023; 9:eadg2059. [PMID: 37235649 PMCID: PMC10219603 DOI: 10.1126/sciadv.adg2059] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 04/21/2023] [Indexed: 05/28/2023]
Abstract
The crossing of environmental barriers poses major adaptive challenges. Rareness of freshwater-marine transitions separates the bacterial communities, but how these are related to brackish counterparts remains elusive, as do the molecular adaptations facilitating cross-biome transitions. We conducted large-scale phylogenomic analysis of freshwater, brackish, and marine quality-filtered metagenome-assembled genomes (11,248). Average nucleotide identity analyses showed that bacterial species rarely existed in multiple biomes. In contrast, distinct brackish basins cohosted numerous species, but their intraspecific population structures displayed clear signs of geographic separation. We further identified the most recent cross-biome transitions, which were rare, ancient, and most commonly directed toward the brackish biome. Transitions were accompanied by systematic changes in amino acid composition and isoelectric point distributions of inferred proteomes, which evolved over millions of years, as well as convergent gains or losses of specific gene functions. Therefore, adaptive challenges entailing proteome reorganization and specific changes in gene content constrains the cross-biome transitions, resulting in species-level separation between aquatic biomes.
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Affiliation(s)
- Krzysztof T. Jurdzinski
- Department of Gene Technology, KTH Royal Institute of Technology, Science for Life Laboratory, Stockholm, Sweden
| | - Maliheh Mehrshad
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Luis Fernando Delgado
- Department of Gene Technology, KTH Royal Institute of Technology, Science for Life Laboratory, Stockholm, Sweden
| | - Ziling Deng
- Department of Gene Technology, KTH Royal Institute of Technology, Science for Life Laboratory, Stockholm, Sweden
| | - Stefan Bertilsson
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Anders F. Andersson
- Department of Gene Technology, KTH Royal Institute of Technology, Science for Life Laboratory, Stockholm, Sweden
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7
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Rhee KY, Jansen RS, Grundner C. Activity-based annotation: the emergence of systems biochemistry. Trends Biochem Sci 2022; 47:785-794. [PMID: 35430135 PMCID: PMC9378515 DOI: 10.1016/j.tibs.2022.03.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/10/2022] [Accepted: 03/22/2022] [Indexed: 01/21/2023]
Abstract
Current tools to annotate protein function have failed to keep pace with the speed of DNA sequencing and exponentially growing number of proteins of unknown function (PUFs). A major contributing factor to this mismatch is the historical lack of high-throughput methods to experimentally determine biochemical activity. Activity-based methods, such as activity-based metabolite and protein profiling, are emerging as new approaches for unbiased, global, biochemical annotation of protein function. In this review, we highlight recent experimental, activity-based approaches that offer new opportunities to determine protein function in a biologically agnostic and systems-level manner.
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Affiliation(s)
- Kyu Y Rhee
- Department of Medicine, Weill Cornell Medical College, New York, NY, USA.
| | - Robert S Jansen
- Department of Microbiology, Radboud University, Nijmegen, The Netherlands.
| | - Christoph Grundner
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Global Health, University of Washington, Seattle, WA, USA; Department of Pediatrics, University of Washington, Seattle, WA, USA.
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8
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Wei H, Moffett JR, Amanat M, Fatemi A, Tsukamoto T, Namboodiri AM, Slusher BS. The pathogenesis of, and pharmacological treatment for, Canavan disease. Drug Discov Today 2022; 27:2467-2483. [DOI: 10.1016/j.drudis.2022.05.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/05/2022] [Accepted: 05/24/2022] [Indexed: 12/12/2022]
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9
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Cao Y, Deng S, Yan L, Gu J, Mao F, Xue Y, Qin L, Jiang Z, Cai W, Zheng C, Nie X, Liu H, Sun Z, Shang F, Tao K, Wang J, Wu K, Zhu B, Cai K. The Prognostic Significance of RIMKLB and Related Immune Infiltrates in Colorectal Cancers. Front Genet 2022; 13:818994. [PMID: 35444692 PMCID: PMC9015428 DOI: 10.3389/fgene.2022.818994] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 03/14/2022] [Indexed: 12/24/2022] Open
Abstract
RimK-like family member B (RIMKLB) is an enzyme that post-translationally modulates ribosomal protein S6, which can affect the development of immune cells. Some studies have suggested its role in tumor progression. However, the relationships among RIMKLB expression, survival outcomes, and tumor-infiltrating immune cells (TIICs) in colorectal cancer (CRC) are still unknown. Therefore, we analyzed RIMKLB expression levels in CRC and normal tissues and investigated the correlations between RIMKLB and TIICs as well as the impact of RIMKLB expression on clinical prognosis in CRC using multiple databases, including the Tumor Immune Estimation Resource (TIMER), Gene Expression Profiling Interactive Analysis (GEPIA), PrognoScan, and UALCAN databases. Enrichment analysis was conducted with the cluster Profiler package in R software to explore the RIMKLB-related biological processes involved in CRC. The RIMKLB expression was significantly decreased in CRC compared to normal tissues, and correlated with histology, stage, lymphatic metastasis, and tumor status (p < 0.05). Patients with CRC with high expression of RIMKLB showed poorer overall survival (OS) (HR = 2.5,p = 0.00,042), and inferior disease-free survival (DFS) (HR = 1.9,p = 0.19) than those with low expression of RIMKLB. TIMER analysis indicated that RIMKLB transcription was closely related with several TIICs, including CD4+ and CD8+ T cells, B cells, tumor-associated macrophages (TAMs), monocytes, neutrophils, natural killer cells, dendritic cells, and subsets of T cells. Moreover, the expression of RIMKLB showed significant positive correlations with infiltrating levels of PD1 (r = 0.223, p = 1.31e-06; r = 0.249, p = 1.25e-03), PDL1 (r = 0.223, p = 6.03e-07; r = 0.41, p = 5.45e-08), and CTLA4 (r = 0.325, p = 9.68e-13; r = 0.41, p = 5.45e-08) in colon and rectum cancer, respectively. Enrichment analysis showed that the RIMKLB expression was positively related to extracellular matrix and immune inflammation-related pathways. In conclusion, RIMKLB expression is associated with survival outcomes and TIICs levels in patients with CRC, and therefore, might be a potential novel prognostic biomarker that reflects the immune infiltration status.
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Affiliation(s)
- Yinghao Cao
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shenghe Deng
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lizhao Yan
- Department of Hand Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Junnan Gu
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fuwei Mao
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yifan Xue
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Le Qin
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhengxing Jiang
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wentai Cai
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Changmin Zheng
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, China
| | - Xiu Nie
- Department of Pathology, Union Hospital, Tongji Medical, Huazhong University of Science and Technology, Wuhan, China
| | - Hongli Liu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhuolun Sun
- Department of Urology, Third Affiliated Hospital of Sun Yat-sen University, Guangzhou0, China
| | - Fumei Shang
- Department of Medical Oncology, Nanyang Central Hospital, Nanyang, China
| | - Kaixiong Tao
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiliang Wang
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ke Wu
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bin Zhu
- Department of Infectious Diseases, Union Hospital, Tongji Medcial College, Huazhong University of Science and Technology, Wuhan, China
| | - Kailin Cai
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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10
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Citrylglutamate synthase deficient male mice are subfertile with impaired histone and transition protein 2 removal in late spermatids. Biochem J 2022; 479:953-972. [PMID: 35419597 DOI: 10.1042/bcj20210844] [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: 12/15/2021] [Revised: 04/13/2022] [Accepted: 04/14/2022] [Indexed: 11/17/2022]
Abstract
Chromatin remodelling in spermatids is an essential step in spermiogenesis and involves the exchange of most histones by protamines, which drives chromatin condensation in late spermatids. The gene Rimklb encodes a citrylglutamate synthase highly expressed in testes of vertebrates and the increase of its reaction product, β-citrylglutamate, correlates in time with the appearance of spermatids. Here we show that deficiency in a functional Rimklb gene leads to male subfertility, which could be partially rescued by in vitro fertilization. Rimklb-deficient mice are impaired in a late step of spermiogenesis and produce spermatozoa with abnormally shaped heads and nuclei. Sperm chromatin in Rimklb-deficient mice was less condensed and showed impaired histone to protamine exchange and retained transition protein 2. These observations suggest that citrylglutamate synthase, probably via its reaction product β-citrylglutamate, is essential for efficient chromatin remodelling during spermiogenesis and may be a possible candidate gene for male subfertility or infertility in humans.
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11
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Becker I, Wang-Eckhardt L, Lodder-Gadaczek J, Wang Y, Grünewald A, Eckhardt M. Mice deficient in the NAAG synthetase II gene Rimkla are impaired in a novel object recognition task. J Neurochem 2021; 157:2008-2023. [PMID: 33638175 DOI: 10.1111/jnc.15333] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/11/2021] [Accepted: 02/21/2021] [Indexed: 12/27/2022]
Abstract
N-acetylaspartylglutamate (NAAG) is an abundant neuropeptide in the mammalian nervous system, synthesized by two related NAAG synthetases I and II (NAAGS-I and -II) encoded by the genes Rimklb and Rimkla, respectively. NAAG plays a role in cognition and memory, according to studies using inhibitors of the NAAG hydrolase glutamate carboxypeptidase II that increase NAAG concentration. To examine consequences of reduced NAAG concentration, Rimkla-deficient (Rimkla-/- ) mice were generated. These mice exhibit normal NAAG level at birth, likely because of the intact Rimklb gene, but have significantly reduced NAAG levels in all brain regions in adulthood. In wild type mice NAAGS-II was most abundant in brainstem and spinal cord, as demonstrated using a new NAAGS-II antiserum. In the hippocampus, NAAGS-II was only detectable in neurons expressing parvalbumin, a marker of GABAergic interneurons. Apart from reduced open field activity, general behavior of adult (6 months old) Rimkla-/- mice examined in different tests (dark-light transition, optokinetic behavior, rotarod, and alternating T-maze) was not significantly altered. However, Rimkla-/- mice were impaired in a short-term novel object recognition test. This was also the case for mice lacking NAA synthase Nat8l, which are devoid of NAAG. Together with results from previous studies showing that inhibition of the NAAG degrading enzyme glutamate carboxypeptidase II is associated with a significant improvement in object recognition, these results suggest a direct involvement of NAAG synthesized by NAAGS-II in the memory consolidation underlying the novel object recognition task.
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Affiliation(s)
- Ivonne Becker
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Lihua Wang-Eckhardt
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Julia Lodder-Gadaczek
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Yong Wang
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Agathe Grünewald
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Matthias Eckhardt
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Bonn, Germany
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12
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Maekura K, Tsukamoto S, Hamada-Kanazawa M, Takano M. Rimklb mutation causes male infertility in mice. Sci Rep 2021; 11:4604. [PMID: 33633267 PMCID: PMC7907349 DOI: 10.1038/s41598-021-84105-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 02/11/2021] [Indexed: 11/23/2022] Open
Abstract
Rimklb is a mammalian homologue of the E. coli enzyme RimK, which catalyzes addition of glutamic acid to the ribosomal protein S6. To date, no previous studies have shown any physiological role for Rimklb in mammals. In this study, using Western blotting, we found that Rimklb is distributed and expressed in mouse testis and heart. Rimklb was subsequently localized to the testicular Leydig cells using immunohistochemistry with an anti-Rimklb antibody. We generated a Rimklb mutant mouse in which a three-base deletion results in deletion of Ala 29 and substitution of Leu 30 with Val, which we named the RimklbA29del, L30V mutant mouse. RimklbA29del, L30V mutant mice show a decrease in testicular size and weight, and in vitro fertilization demonstrates complete male infertility. Furthermore, we found that a key factor in the mammalian target of the rapamycin/ribosomal protein S6 transcriptional pathway is hyperphosphorylated in the seminiferous tubules of the mutant testis. We conclude that Rimklb has important roles that include spermatogenesis in seminiferous tubules. In summary, male RimklbA29del, L30V mice are infertile.
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Affiliation(s)
- Koji Maekura
- Laboratory of Molecular Cellular Biology, School of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3 Minatojima, Chuo-ku, Kobe, 650-8586, Japan
| | - Satoshi Tsukamoto
- Laboratory Animal and Genome Sciences Section, National Institute for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Michiko Hamada-Kanazawa
- Laboratory of Molecular Cellular Biology, School of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3 Minatojima, Chuo-ku, Kobe, 650-8586, Japan
| | - Masaoki Takano
- Laboratory of Molecular Cellular Biology, School of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3 Minatojima, Chuo-ku, Kobe, 650-8586, Japan.
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13
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Williams S, Rae CD. Long reach of the NAAG family tree: An Editorial for "Evidence of NAAG-family tripeptide NAAG2 in the Drosophila nervous system" on page 38. J Neurochem 2020; 156:13-15. [PMID: 33197055 DOI: 10.1111/jnc.15213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 10/06/2020] [Indexed: 11/27/2022]
Abstract
The last common ancestor of humans and fruit flies lived about 800 million years ago, yet both of us have nervous systems that share a number of common important features, for example the use of glutamate as a neurotransmitter. We can now possibly add another common feature to the neural tissue of humans and fruit flies which is that of N-acetylaspartylglutamate (NAAG) peptides. This Editorial highlights an article by Kozik and coworkers in the current issue of the Journal of Neurochemistry, in which the authors report the discovery, in Drosophila melanogaster nervous system, of NAA-glutamylglutamate (NAAG2).
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Affiliation(s)
- Steve Williams
- Imaging Science and Biomedical Engineering, University of Manchester, Manchester, UK
| | - Caroline D Rae
- NeuRA Imaging, Neuroscience Research Australia, Randwick, NSW, Australia
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14
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Zarei I, Oppel RC, Borresen EC, Brown RJ, Ryan EP. Modulation of plasma and urine metabolome in colorectal cancer survivors consuming rice bran. ACTA ACUST UNITED AC 2019; 6. [PMID: 31396400 DOI: 10.15761/ifnm.1000252] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Rice bran has bioactive phytochemicals with cancer protective actions that involve metabolism by the host and the gut microbiome. Globally, colorectal cancer (CRC) is the third leading cause of cancer-related death and the increased incidence is largely attributed to poor dietary patterns, including low daily fiber intake. A dietary intervention trial was performed to investigate the impact of rice bran consumption on the plasma and urine metabolome of CRC survivors. Nineteen CRC survivors participated in a randomized-controlled trial that included consumption of heat-stabilized rice bran (30 g/day) or a control diet without rice bran for 4 weeks. A fasting plasma and first void of the morning urine sample were analyzed by non-targeted metabolomics using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). After 4 weeks of either rice bran or control diets, 12 plasma and 16 urine metabolites were significantly different between the groups (p≤0.05). Rice bran intake increased relative abundance of plasma mannose (1.373-fold) and beta-citrylglutamate (BCG) (1.593-fold), as well as increased urine N-formylphenylalanine (2.191-fold) and dehydroisoandrosterone sulfate (DHEA-S) (4.488-fold). Diet affected metabolites, such as benzoate, mannose, eicosapentaenoate (20:5n3) (EPA), and N-formylphenylalanine have been previously reported for cancer protection and were identified from the rice bran food metabolome. Nutritional metabolome changes following increased consumption of whole grains such as rice bran warrants continued investigation for colon cancer control and prevention attributes as dietary biomarkers for positive effects are needed to reduce high risk for colorectal cancer recurrence.
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Affiliation(s)
- Iman Zarei
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - Renee C Oppel
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - Erica C Borresen
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - Regina J Brown
- University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Elizabeth P Ryan
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USA
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15
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Tang J, O’Neill J, Alger JR, Shen Z, Johnson MC, London ED. N-Acetyl and Glutamatergic Neurometabolites in Perisylvian Brain Regions of Methamphetamine Users. Int J Neuropsychopharmacol 2019; 22:1-9. [PMID: 29788422 PMCID: PMC6313110 DOI: 10.1093/ijnp/pyy042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 03/21/2018] [Accepted: 05/15/2018] [Indexed: 02/05/2023] Open
Abstract
Background Methamphetamine induces neuronal N-acetyl-aspartate synthesis in preclinical studies. In a preliminary human proton magnetic resonance spectroscopic imaging investigation, we also observed that N-acetyl-aspartate+N-acetyl-aspartyl-glutamate in right inferior frontal cortex correlated with years of heavy methamphetamine abuse. In the same brain region, glutamate+glutamine is lower in methamphetamine users than in controls and is negatively correlated with depression. N-acetyl and glutamatergic neurochemistries therefore merit further investigation in methamphetamine abuse and the associated mood symptoms. Methods Magnetic resonance spectroscopic imaging was used to measure N-acetyl-aspartate+N-acetyl-aspartyl-glutamate and glutamate+glutamine in bilateral inferior frontal cortex and insula, a neighboring perisylvian region affected by methamphetamine, of 45 abstinent methamphetamine-dependent and 45 healthy control participants. Regional neurometabolite levels were tested for group differences and associations with duration of heavy methamphetamine use, depressive symptoms, and state anxiety. Results In right inferior frontal cortex, N-acetyl-aspartate+N-acetyl-aspartyl-glutamate correlated with years of heavy methamphetamine use (r = +0.45); glutamate+glutamine was lower in methamphetamine users than in controls (9.3%) and correlated negatively with depressive symptoms (r = -0.44). In left insula, N-acetyl-aspartate+N-acetyl-aspartyl-glutamate was 9.1% higher in methamphetamine users than controls. In right insula, glutamate+glutamine was 12.3% lower in methamphetamine users than controls and correlated negatively with depressive symptoms (r = -0.51) and state anxiety (r = -0.47). Conclusions The inferior frontal cortex and insula show methamphetamine-related abnormalities, consistent with prior observations of increased cortical N-acetyl-aspartate in methamphetamine-exposed animal models and associations between cortical glutamate and mood in human methamphetamine users.
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Affiliation(s)
- Jinsong Tang
- Laboratory of Molecular Neuroimaging, Semel Institute for Neuroscience and Human Behavior and Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, California
- Second Xiangya Hospital, Central South University, Changsha, China
| | - Joseph O’Neill
- Division of Child and Adolescent Psychiatry, Semel Institute for Neuroscience and Human Behavior and Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, California
| | | | - Zhiwei Shen
- The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Maritza C Johnson
- Laboratory of Molecular Neuroimaging, Semel Institute for Neuroscience and Human Behavior and Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, California
| | - Edythe D London
- Laboratory of Molecular Neuroimaging, Semel Institute for Neuroscience and Human Behavior and Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, California
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California
- Brain Research Institute, University of California, Los Angeles, California
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16
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Arimura Y, Kono T, Kino K, Kurumizaka H. Structural polymorphism of the Escherichia coli poly-α-L-glutamate synthetase RimK. Acta Crystallogr F Struct Biol Commun 2018; 74:385-390. [PMID: 29969101 PMCID: PMC6038451 DOI: 10.1107/s2053230x18007689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 05/23/2018] [Indexed: 11/11/2022] Open
Abstract
Bacterial RimK is an enzyme that catalyzes the polyglutamylation of the C-terminus of ribosomal protein S6 and the synthesis of poly-α-L-glutamate peptides using L-glutamic acid. In the present study, the crystal structure of the Escherichia coli RimK protein complexed with the ATP analogue AMP-PNP was determined at 2.05 Å resolution. Two different conformations of RimK, closed and open forms, were observed in the crystals. The structural polymorphism revealed in this study provided important information to understand the mechanism by which RimK catalyzes the synthesis of poly-α-L-glutamate peptides and the polyglutamylation of ribosomal protein S6.
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Affiliation(s)
- Yasuhiro Arimura
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Tomonori Kono
- Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Kuniki Kino
- Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
- Institute for Medical-oriented Structural Biology, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
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17
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Duarte JMN, Xin L. Magnetic Resonance Spectroscopy in Schizophrenia: Evidence for Glutamatergic Dysfunction and Impaired Energy Metabolism. Neurochem Res 2018; 44:102-116. [PMID: 29616444 PMCID: PMC6345729 DOI: 10.1007/s11064-018-2521-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 03/28/2018] [Accepted: 03/30/2018] [Indexed: 01/03/2023]
Abstract
In the past couple of decades, major efforts were made to increase reliability of metabolic assessments by magnetic resonance methods. Magnetic resonance spectroscopy (MRS) has been valuable for providing in vivo evidence and investigating biomarkers in neuropsychiatric disorders, namely schizophrenia. Alterations of glutamate and glutamine levels in brains of schizophrenia patients relative to healthy subjects are generally interpreted as markers of glutamatergic dysfunction. However, only a small fraction of MRS-detectable glutamate is involved in neurotransmission. Here we review and discuss brain metabolic processes that involve glutamate and that are likely to be implicated in neuropsychiatric disorders.
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Affiliation(s)
- João M N Duarte
- Department of Experimental Medical Science, Faculty of Medicine, Lund University, BMC C11, Sölvegatan 19, 221 84, Lund, Sweden. .,Wallenberg Center for Molecular Medicine, Lund University, Lund, Sweden.
| | - Lijing Xin
- Animal Imaging and Technology Core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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18
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Woon MT, Long PA, Reilly L, Evans JM, Keefe AM, Lea MR, Beglinger CJ, Balijepalli RC, Lee Y, Olson TM, Kamp TJ. Pediatric Dilated Cardiomyopathy-Associated LRRC10 (Leucine-Rich Repeat-Containing 10) Variant Reveals LRRC10 as an Auxiliary Subunit of Cardiac L-Type Ca 2+ Channels. J Am Heart Assoc 2018; 7:e006428. [PMID: 29431102 PMCID: PMC5850229 DOI: 10.1161/jaha.117.006428] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Accepted: 11/10/2017] [Indexed: 12/30/2022]
Abstract
BACKGROUND Genetic causes of dilated cardiomyopathy (DCM) are incompletely understood. LRRC10 (leucine-rich repeat-containing 10) is a cardiac-specific protein of unknown function. Heterozygous mutations in LRRC10 have been suggested to cause DCM, and deletion of Lrrc10 in mice results in DCM. METHODS AND RESULTS Whole-exome sequencing was carried out on a patient who presented at 6 weeks of age with DCM and her unaffected parents, filtering for rare, deleterious, recessive, and de novo variants. Whole-exome sequencing followed by trio-based filtering identified a homozygous recessive variant in LRRC10, I195T. Coexpression of I195T LRRC10 with the L-type Ca2+ channel (Cav1.2, β2CN2, and α2δ subunits) in HEK293 cells resulted in a significant ≈0.5-fold decrease in ICa,L at 0 mV, in contrast to the ≈1.4-fold increase in ICa,L by coexpression of LRRC10 (n=9-12, P<0.05). Coexpression of LRRC10 or I195T LRRC10 did not alter the surface membrane expression of Cav1.2. LRRC10 coexpression with Cav1.2 in the absence of auxiliary β2CN2 and α2δ subunits revealed coassociation of Cav1.2 and LRRC10 and a hyperpolarizing shift in the voltage dependence of activation (n=6-9, P<0.05). Ventricular myocytes from Lrrc10-/- mice had significantly smaller ICa,L, and coimmunoprecipitation experiments confirmed association between LRRC10 and the Cav1.2 subunit in mouse hearts. CONCLUSIONS Examination of a patient with DCM revealed homozygosity for a previously unreported LRRC10 variant: I195T. Wild-type and I195T LRRC10 function as cardiac-specific subunits of L-type Ca2+ channels and exert dramatically different effects on channel gating, providing a potential link to DCM.
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Affiliation(s)
- Marites T Woon
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Pamela A Long
- Mayo Graduate School, Molecular Pharmacology and Experimental Therapeutics Track, Mayo Clinic, Rochester, MN
| | - Louise Reilly
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Jared M Evans
- Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, MN
| | - Alexis M Keefe
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Martin R Lea
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Carl J Beglinger
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Ravi C Balijepalli
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Youngsook Lee
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI
| | - Timothy M Olson
- Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, MN
| | - Timothy J Kamp
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
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19
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Ellens KW, Christian N, Singh C, Satagopam VP, May P, Linster CL. Confronting the catalytic dark matter encoded by sequenced genomes. Nucleic Acids Res 2017; 45:11495-11514. [PMID: 29059321 PMCID: PMC5714238 DOI: 10.1093/nar/gkx937] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 10/03/2017] [Indexed: 01/02/2023] Open
Abstract
The post-genomic era has provided researchers with a deluge of protein sequences. However, a significant fraction of the proteins encoded by sequenced genomes remains without an identified function. Here, we aim at determining how many enzymes of uncertain or unknown function are still present in the Saccharomyces cerevisiae and human proteomes. Using information available in the Swiss-Prot, BRENDA and KEGG databases in combination with a Hidden Markov Model-based method, we estimate that >600 yeast and 2000 human proteins (>30% of their proteins of unknown function) are enzymes whose precise function(s) remain(s) to be determined. This illustrates the impressive scale of the ‘unknown enzyme problem’. We extensively review classical biochemical as well as more recent systematic experimental and computational approaches that can be used to support enzyme function discovery research. Finally, we discuss the possible roles of the elusive catalysts in light of recent developments in the fields of enzymology and metabolism as well as the significance of the unknown enzyme problem in the context of metabolic modeling, metabolic engineering and rare disease research.
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Affiliation(s)
- Kenneth W Ellens
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, L-4362 Esch-sur-Alzette, Luxembourg
| | - Nils Christian
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, L-4362 Esch-sur-Alzette, Luxembourg
| | - Charandeep Singh
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, L-4362 Esch-sur-Alzette, Luxembourg
| | - Venkata P Satagopam
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, L-4362 Esch-sur-Alzette, Luxembourg
| | - Patrick May
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, L-4362 Esch-sur-Alzette, Luxembourg
| | - Carole L Linster
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, L-4362 Esch-sur-Alzette, Luxembourg
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20
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Piper T, Mehling LM, Spottke A, Heidbreder A, Young P, Madea B, Hess C, Schänzer W, Thevis M. Potential of GHB phase-II-metabolites to complement current approaches in GHB post administration detection. Forensic Sci Int 2017; 279:157-164. [PMID: 28869822 DOI: 10.1016/j.forsciint.2017.08.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/11/2017] [Accepted: 08/21/2017] [Indexed: 10/19/2022]
Abstract
Recently, phase-II-metabolites of γ-hydroxybutyric acid (GHB), namely GHB-β-O-glucuronide and GHB-4-sulfate, were implemented in the scope of drug testing methods The clearance of GHB from the circulation is extremely fast due to its incorporation into the metabolic pathway of the citrate cycle. The elimination half-life of GHB from blood was reported to be dose dependent between 30 and 50min resulting in narrow detection windows of less than 12h after illicit administration or cases of drug facilitated sexual assault regardless of the biological matrix used. As sulfated metabolites tend to show prolonged half-lives and slower elimination kinetics compared to unmodified or glucuronidated drugs, the potential of GHB-4-sulfate in prolonging the detection of GHB administration was assessed. Its urinary concentrations were determined in n=100 samples from athletes and n=50 samples from sport students, and the resulting data were used to calculate a preliminary reference population-based threshold for urinary GHB-sulfate concentration. The threshold was then compared to concentrations found in post-administration urine samples collected from 3 volunteers who administered GHB within the setting of a clinical trial. Due to the large inter-individual variability of concentrations found in the reference population, GHB-4-sulfate itself was not suitable to prolong the detection times for GHB applications, even when specific gravity-corrected values were used. Therefore, a metabolomics-based approach was applied to the reference population samples and evaluated regarding other urinary metabolites that potentially correlate with the urinary excretion of GHB-4-sulfate and GHB-β-O-glucuronide in order to find a suitable marker to normalize urinary concentrations. The most promising candidate was found at a molecular mass of 321.0696 and was preliminarily identified as β-citryl-glutamic acid.
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Affiliation(s)
- Thomas Piper
- German Sport University Cologne, Center for Preventive Doping Research, Am Sportpark Müngersdorf 6, 50933 Köln, Germany.
| | - Lena-Maria Mehling
- Institute of Forensic Medicine, University of Bonn, Stiftsplatz 12, 53111 Bonn, Germany
| | - Annika Spottke
- Department of Neurology, University Hospital, University of Bonn, Sigmund-Freud-Straße 25, 53127 Bonn, Germany
| | - Anna Heidbreder
- Division of Sleep Medicine and Neuromuscular Disorders, Department of Neurology, University Hospital, University of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany
| | - Peter Young
- Division of Sleep Medicine and Neuromuscular Disorders, Department of Neurology, University Hospital, University of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany
| | - Burkhard Madea
- Institute of Forensic Medicine, University of Bonn, Stiftsplatz 12, 53111 Bonn, Germany
| | - Cornelius Hess
- Institute of Forensic Medicine, University of Bonn, Stiftsplatz 12, 53111 Bonn, Germany
| | - Wilhelm Schänzer
- German Sport University Cologne, Center for Preventive Doping Research, Am Sportpark Müngersdorf 6, 50933 Köln, Germany
| | - Mario Thevis
- German Sport University Cologne, Center for Preventive Doping Research, Am Sportpark Müngersdorf 6, 50933 Köln, Germany
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21
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Griffith CM, Williams PB, Tinoco LW, Dinges MM, Wang Y, Larive CK. 1H NMR Metabolic Profiling of Earthworm (Eisenia fetida) Coelomic Fluid, Coelomocytes, and Tissue: Identification of a New Metabolite-Malylglutamate. J Proteome Res 2017; 16:3407-3418. [PMID: 28753027 PMCID: PMC5585853 DOI: 10.1021/acs.jproteome.7b00439] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
![]()
Earthworm metabolism
is recognized
as a useful tool for monitoring environmental insults and measuring
ecotoxicity, yet extensive earthworm metabolic profiling using 1H nuclear magnetic resonance (NMR) spectroscopy has been limited
in scope. This study aims to expand the embedded metabolic material
in earthworm coelomic fluid, coelomocytes, and tissue to aid systems
toxicology research. Fifty-nine metabolites within Eisenia
fetida were identified, with 47 detected in coelomic fluid,
41 in coelomocytes, and 54 in whole-worm samples and tissue extracts.
The newly detected but known metabolites 2-aminobutyrate, nicotinurate, Nδ,Nδ,Nδ-trimethylornithine,
and trigonelline are reported along with a novel compound, malylglutamate,
elucidated using 2D NMR and high-resolution MS/MS. We postulate that
malylglutamate acts as a glutamate/malate store, chelator, and anionic
osmolyte and helps to provide electrolyte balance.
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Affiliation(s)
- Corey M Griffith
- Environmental Toxicology Graduate Program, University of California , Riverside, California 92521, United States
| | - Preston B Williams
- Department of Chemistry, University of California , Riverside, California 92521, United States
| | - Luzineide W Tinoco
- Department of Chemistry, University of California , Riverside, California 92521, United States.,Laboratório Multiusuário de Análises por Ressonância Magnética Nuclear, Instituto de Pesquisas de Produtos Naturais, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro , Rio de Janeiro, Rio de Janeiro CEP 21941-902, Brazil
| | - Meredith M Dinges
- Department of Chemistry, University of California , Riverside, California 92521, United States
| | - Yinsheng Wang
- Environmental Toxicology Graduate Program, University of California , Riverside, California 92521, United States.,Department of Chemistry, University of California , Riverside, California 92521, United States
| | - Cynthia K Larive
- Environmental Toxicology Graduate Program, University of California , Riverside, California 92521, United States.,Department of Chemistry, University of California , Riverside, California 92521, United States
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22
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Appu AP, Moffett JR, Arun P, Moran S, Nambiar V, Krishnan JKS, Puthillathu N, Namboodiri AMA. Increasing N-acetylaspartate in the Brain during Postnatal Myelination Does Not Cause the CNS Pathologies of Canavan Disease. Front Mol Neurosci 2017; 10:161. [PMID: 28626388 PMCID: PMC5454052 DOI: 10.3389/fnmol.2017.00161] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 05/09/2017] [Indexed: 01/03/2023] Open
Abstract
Canavan disease is caused by mutations in the gene encoding aspartoacylase (ASPA), a deacetylase that catabolizes N-acetylaspartate (NAA). The precise involvement of elevated NAA in the pathogenesis of Canavan disease is an ongoing debate. In the present study, we tested the effects of elevated NAA in the brain during postnatal development. Mice were administered high doses of the hydrophobic methyl ester of NAA (M-NAA) twice daily starting on day 7 after birth. This treatment increased NAA levels in the brain to those observed in the brains of Nur7 mice, an established model of Canavan disease. We evaluated various serological parameters, oxidative stress, inflammatory and neurodegeneration markers and the results showed that there were no pathological alterations in any measure with increased brain NAA levels. We examined oxidative stress markers, malondialdehyde content (indicator of lipid peroxidation), expression of NADPH oxidase and nuclear translocation of the stress-responsive transcription factor nuclear factor (erythroid-derived 2)-like 2 (NRF-2) in brain. We also examined additional pathological markers by immunohistochemistry and the expression of activated caspase-3 and interleukin-6 by Western blot. None of the markers were increased in the brains of M-NAA treated mice, and no vacuoles were observed in any brain region. These results show that ASPA expression prevents the pathologies associated with excessive NAA concentrations in the brain during postnatal myelination. We hypothesize that the pathogenesis of Canavan disease involves not only disrupted NAA metabolism, but also excessive NAA related signaling processes in oligodendrocytes that have not been fully determined and we discuss some of the potential mechanisms.
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Affiliation(s)
- Abhilash P. Appu
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - John R. Moffett
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - Peethambaran Arun
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - Sean Moran
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - Vikram Nambiar
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - Jishnu K. S. Krishnan
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - Narayanan Puthillathu
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - Aryan M. A. Namboodiri
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
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Li G, Liu Y, Liu C, Su Z, Ren S, Wang Y, Deng T, Huang D, Tian Y, Qiu Y. Genome-wide analyses of long noncoding RNA expression profiles correlated with radioresistance in nasopharyngeal carcinoma via next-generation deep sequencing. BMC Cancer 2016; 16:719. [PMID: 27599611 PMCID: PMC5012053 DOI: 10.1186/s12885-016-2755-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 08/31/2016] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Radioresistance is one of the major factors limiting the therapeutic efficacy and prognosis of patients with nasopharyngeal carcinoma (NPC). Accumulating evidence has suggested that aberrant expression of long noncoding RNAs (lncRNAs) contributes to cancer progression. Therefore, here we identified lncRNAs associated with radioresistance in NPC. METHODS The differential expression profiles of lncRNAs associated with NPC radioresistance were constructed by next-generation deep sequencing by comparing radioresistant NPC cells with their parental cells. LncRNA-related mRNAs were predicted and analyzed using bioinformatics algorithms compared with the mRNA profiles related to radioresistance obtained in our previous study. Several lncRNAs and associated mRNAs were validated in established NPC radioresistant cell models and NPC tissues. RESULTS By comparison between radioresistant CNE-2-Rs and parental CNE-2 cells by next-generation deep sequencing, a total of 781 known lncRNAs and 2054 novel lncRNAs were annotated. The top five upregulated and downregulated known/novel lncRNAs were detected using quantitative real-time reverse transcription-polymerase chain reaction, and 7/10 known lncRNAs and 3/10 novel lncRNAs were demonstrated to have significant differential expression trends that were the same as those predicted by deep sequencing. From the prediction process, 13 pairs of lncRNAs and their associated genes were acquired, and the prediction trends of three pairs were validated in both radioresistant CNE-2-Rs and 6-10B-Rs cell lines, including lncRNA n373932 and SLITRK5, n409627 and PRSS12, and n386034 and RIMKLB. LncRNA n373932 and its related SLITRK5 showed dramatic expression changes in post-irradiation radioresistant cells and a negative expression correlation in NPC tissues (R = -0.595, p < 0.05). CONCLUSIONS Our study provides an overview of the expression profiles of radioresistant lncRNAs and potentially related mRNAs, which will facilitate future investigations into the function of lncRNAs in NPC radioresistance.
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Affiliation(s)
- Guo Li
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Xiangya Road, Changsha, 410008, Hunan, China.,Otolaryngology Major Disease Research Key Laboratory of Hunan Province, Xiangya Road, Changsha, 410008, Hunan, China
| | - Yong Liu
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Xiangya Road, Changsha, 410008, Hunan, China.,Otolaryngology Major Disease Research Key Laboratory of Hunan Province, Xiangya Road, Changsha, 410008, Hunan, China
| | - Chao Liu
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Xiangya Road, Changsha, 410008, Hunan, China.,Otolaryngology Major Disease Research Key Laboratory of Hunan Province, Xiangya Road, Changsha, 410008, Hunan, China
| | - Zhongwu Su
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Xiangya Road, Changsha, 410008, Hunan, China.,Otolaryngology Major Disease Research Key Laboratory of Hunan Province, Xiangya Road, Changsha, 410008, Hunan, China
| | - Shuling Ren
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Xiangya Road, Changsha, 410008, Hunan, China.,Otolaryngology Major Disease Research Key Laboratory of Hunan Province, Xiangya Road, Changsha, 410008, Hunan, China
| | - Yunyun Wang
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Xiangya Road, Changsha, 410008, Hunan, China.,Otolaryngology Major Disease Research Key Laboratory of Hunan Province, Xiangya Road, Changsha, 410008, Hunan, China
| | - Tengbo Deng
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Xiangya Road, Changsha, 410008, Hunan, China.,Otolaryngology Major Disease Research Key Laboratory of Hunan Province, Xiangya Road, Changsha, 410008, Hunan, China
| | - Donghai Huang
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Xiangya Road, Changsha, 410008, Hunan, China.,Otolaryngology Major Disease Research Key Laboratory of Hunan Province, Xiangya Road, Changsha, 410008, Hunan, China
| | - Yongquan Tian
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Xiangya Road, Changsha, 410008, Hunan, China.,Otolaryngology Major Disease Research Key Laboratory of Hunan Province, Xiangya Road, Changsha, 410008, Hunan, China
| | - Yuanzheng Qiu
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Xiangya Road, Changsha, 410008, Hunan, China. .,Otolaryngology Major Disease Research Key Laboratory of Hunan Province, Xiangya Road, Changsha, 410008, Hunan, China.
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24
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A conserved phosphatase destroys toxic glycolytic side products in mammals and yeast. Nat Chem Biol 2016; 12:601-7. [PMID: 27294321 DOI: 10.1038/nchembio.2104] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 03/28/2016] [Indexed: 11/08/2022]
Abstract
Metabolic enzymes are very specific. However, most of them show weak side activities toward compounds that are structurally related to their physiological substrates, thereby producing side products that may be toxic. In some cases, 'metabolite repair enzymes' eliminating side products have been identified. We show that mammalian glyceraldehyde 3-phosphate dehydrogenase and pyruvate kinase, two core glycolytic enzymes, produce 4-phosphoerythronate and 2-phospho-L-lactate, respectively. 4-Phosphoerythronate strongly inhibits an enzyme of the pentose phosphate pathway, whereas 2-phospho-L-lactate inhibits the enzyme producing the glycolytic activator fructose 2,6-bisphosphate. We discovered that a single, widely conserved enzyme, known as phosphoglycolate phosphatase (PGP) in mammals, dephosphorylates both 4-phosphoerythronate and 2-phospho-L-lactate, thereby preventing a block in the pentose phosphate pathway and glycolysis. Its yeast ortholog, Pho13, similarly dephosphorylates 4-phosphoerythronate and 2-phosphoglycolate, a side product of pyruvate kinase. Our work illustrates how metabolite repair enzymes can make up for the limited specificity of metabolic enzymes and permit high flux in central metabolic pathways.
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25
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Weindl D, Cordes T, Battello N, Sapcariu SC, Dong X, Wegner A, Hiller K. Bridging the gap between non-targeted stable isotope labeling and metabolic flux analysis. Cancer Metab 2016; 4:10. [PMID: 27110360 PMCID: PMC4842284 DOI: 10.1186/s40170-016-0150-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 03/31/2016] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Metabolism gained increasing interest for the understanding of diseases and to pinpoint therapeutic intervention points. However, classical metabolomics techniques only provide a very static view on metabolism. Metabolic flux analysis methods, on the other hand, are highly targeted and require detailed knowledge on metabolism beforehand. RESULTS We present a novel workflow to analyze non-targeted metabolome-wide stable isotope labeling data to detect metabolic flux changes in a non-targeted manner. Furthermore, we show how similarity-analysis of isotopic enrichment patterns can be used for pathway contextualization of unidentified compounds. We illustrate our approach with the analysis of changes in cellular metabolism of human adenocarcinoma cells in response to decreased oxygen availability. Starting without a priori knowledge, we detect metabolic flux changes, leading to an increased glutamine contribution to acetyl-CoA production, reveal biosynthesis of N-acetylaspartate by N-acetyltransferase 8-like (NAT8L) in lung cancer cells and show that NAT8L silencing inhibits proliferation of A549, JHH-4, PH5CH8, and BEAS-2B cells. CONCLUSIONS Differential stable isotope labeling analysis provides qualitative metabolic flux information in a non-targeted manner. Furthermore, similarity analysis of enrichment patterns provides information on metabolically closely related compounds. N-acetylaspartate and NAT8L are important players in cancer cell metabolism, a context in which they have not received much attention yet.
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Affiliation(s)
- Daniel Weindl
- />Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, Avenue des Hauts Fourneaux, Esch-sur-Alzette, 4362 Luxembourg
| | - Thekla Cordes
- />Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, Avenue des Hauts Fourneaux, Esch-sur-Alzette, 4362 Luxembourg
- />Department of Bioengineering, University of California, Gilman Drive, San Diego, La Jolla, 92037 USA
| | - Nadia Battello
- />Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, Avenue des Hauts Fourneaux, Esch-sur-Alzette, 4362 Luxembourg
| | - Sean C. Sapcariu
- />Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, Avenue des Hauts Fourneaux, Esch-sur-Alzette, 4362 Luxembourg
| | - Xiangyi Dong
- />Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, Avenue des Hauts Fourneaux, Esch-sur-Alzette, 4362 Luxembourg
| | - Andre Wegner
- />Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, Avenue des Hauts Fourneaux, Esch-sur-Alzette, 4362 Luxembourg
| | - Karsten Hiller
- />Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, Avenue des Hauts Fourneaux, Esch-sur-Alzette, 4362 Luxembourg
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26
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Abstract
Amides are widespread in biologically active compounds with a broad range of applications in biotechnology, agriculture and medicine. Therefore, as alternative to chemical synthesis the biocatalytic amide synthesis is a very interesting field of research. As usual, Nature can serve as guide in the quest for novel biocatalysts. Several mechanisms for carboxylate activation involving mainly acyl-adenylate, acyl-phosphate or acyl-enzyme intermediates have been discovered, but also completely different pathways to amides are found. In addition to ribosomes, selected enzymes of almost all main enzyme classes are able to synthesize amides. In this review we give an overview about amide synthesis in Nature, as well as biotechnological applications of these enzymes. Moreover, several examples of biocatalytic amide synthesis are given.
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27
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Khacho P, Wang B, Bergeron R. The Good and Bad Sides of NAAG. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 76:311-49. [PMID: 27288081 DOI: 10.1016/bs.apha.2016.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Why has such a small peptide been the source of controversy in neuroscience over the last 5 decades? Is N-acetyl-aspartyl-glutamate (NAAG) a neurotransmitter? Is NAAG located in neuronal tissue or in astrocytes? Is NAAG involved in neuropsychiatric and neurodegenerative disorders? Is NAAG therapeutically beneficial in the treatment of stroke or in initiating cascades of events leading to psychosis? After many years of intense research there is no clear consensus within the scientific community on how NAAG behaves in the brain. One of the major controversies about NAAG is its physiological action at N-methyl-d-aspartate (NMDA) receptors. While some researchers strongly argue that NAAG acts as a weak agonist at NMDA receptors, others have suggested that NAAG could behave as a potent antagonist. Published data from our laboratory demonstrate that the effect of NAAG on NMDA receptors could be influenced by a number of factors including the subcellular localization and subunit composition of NMDA receptors, as well as protons. In this chapter, we will summarize the knowledge of the literature on NAAG, however, we will place emphasis on our recently published data. More specifically, we have reported interesting findings on the effects of NAAG on NMDA receptors at synaptic and extrasynaptic sites using a pharmacological paradigm to distinguish the two populations of NMDA receptors. Additionally, we have evaluated the role of NAAG on GluN2A- and GluN2B-containing NMDA receptors using a HEK293 cell recombinant system. Finally, we have studied the effects of NAAG on GluN2A- and GluN2B-containing NMDA receptors in different extracellular pH conditions. We believe that our findings could potentially resolve some aspects of the debate regarding the role of NAAG at NMDA receptors.
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Affiliation(s)
- P Khacho
- University of Ottawa, Ottawa, ON, Canada
| | - B Wang
- University of Ottawa, Ottawa, ON, Canada
| | - R Bergeron
- University of Ottawa, Ottawa, ON, Canada; Ottawa Hospital Research Institute, Ottawa, ON, Canada.
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N-Acetylaspartate Synthase Deficiency Corrects the Myelin Phenotype in a Canavan Disease Mouse Model But Does Not Affect Survival Time. J Neurosci 2016; 35:14501-16. [PMID: 26511242 DOI: 10.1523/jneurosci.1056-15.2015] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Canavan disease (CD) is a severe, lethal leukodystrophy caused by deficiency in aspartoacylase (ASPA), which hydrolyzes N-acetylaspartate (NAA). In the brains of CD patients, NAA accumulates to high millimolar concentrations. The pathology of the disease is characterized by loss of oligodendrocytes and spongy myelin degeneration in the CNS. Whether accumulating NAA, absence of NAA-derived acetate, or absence of any unknown functions of the ASPA enzyme is responsible for the pathology of the disease is not fully understood. We generated ASPA-deficient (Aspa(nur7/nur7)) mice that are also deficient for NAA synthase Nat8L (Nat8L(-/-)/Aspa(nur7/nur7)). These mice have no detectable NAA. Nevertheless, they exhibited normal myelin content, myelin sphingolipid composition, and full reversal of spongy myelin and axonal degeneration. Surprisingly, although pathology was fully reversed, the survival time of the mice was not prolonged. In contrast, Aspa(nur7/nur7) mice with only one intact Nat8L allele accumulated less NAA, developed a less severe pathology, phenotypic improvements, and, importantly, an almost normal survival time. Therefore, inhibition of NAA synthase is a promising therapeutic option for CD. The reduced survival rate of Nat8L(-/-)/Aspa(nur7/nur7) mice, however, indicates that complete inhibition of NAA synthase may bear unforeseeable risks for the patient. Furthermore, we demonstrate that acetate derived from NAA is not essential for myelin lipid synthesis and that loss of NAA-derived acetate does not cause the myelin phenotype of Aspa(nur7/nur7) mice. Our data clearly support the hypothesis that NAA accumulation is the major factor in the development of CD.
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Still NAAG’ing After All These Years. NEUROPSYCHOPHARMACOLOGY: A TRIBUTE TO JOSEPH T. COYLE 2016; 76:215-55. [DOI: 10.1016/bs.apha.2016.01.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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30
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A pathway map of glutamate metabolism. J Cell Commun Signal 2015; 10:69-75. [PMID: 26635200 DOI: 10.1007/s12079-015-0315-5] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 11/25/2015] [Indexed: 10/22/2022] Open
Abstract
Glutamate metabolism plays a vital role in biosynthesis of nucleic acids and proteins. It is also associated with a number of different stress responses. Deficiency of enzymes involved in glutamate metabolism is associated with various disorders including gyrate atrophy, hyperammonemia, hemolytic anemia, γ-hydoxybutyric aciduria and 5-oxoprolinuria. Here, we present a pathway map of glutamate metabolism representing metabolic intermediates in the pathway, 107 regulator molecules, 9 interactors and 3 types of post-translational modifications. This pathway map provides detailed information about enzyme regulation, protein-enzyme interactions, post-translational modifications of enzymes and disorders due to enzyme deficiency. The information included in the map was based on published experimental evidence reported from mammalian systems.
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31
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Jansen RS, Mahakena S, de Haas M, Borst P, van de Wetering K. ATP-binding Cassette Subfamily C Member 5 (ABCC5) Functions as an Efflux Transporter of Glutamate Conjugates and Analogs. J Biol Chem 2015; 290:30429-40. [PMID: 26515061 DOI: 10.1074/jbc.m115.692103] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Indexed: 01/12/2023] Open
Abstract
The ubiquitous efflux transporter ABCC5 (ATP-binding cassette subfamily C member 5) is present at high levels in the blood-brain barrier, neurons, and glia, but its in vivo substrates and function are not known. Using untargeted metabolomic screens, we show that Abcc5(-/-) mice accumulate endogenous glutamate conjugates in several tissues, but brain in particular. The abundant neurotransmitter N-acetylaspartylglutamate was 2.4-fold higher in Abcc5(-/-) brain. The metabolites that accumulated in Abcc5(-/-) tissues were depleted in cultured cells that overexpressed human ABCC5. In a vesicular membrane transport assay, ABCC5 also transported exogenous glutamate analogs, like the classic excitotoxic neurotoxins kainic acid, domoic acid, and NMDA; the therapeutic glutamate analog ZJ43; and, as previously shown, the anti-cancer drug methotrexate. Glutamate conjugates and analogs are of physiological relevance because they can affect the function of glutamate, the principal excitatory neurotransmitter in the brain. After CO2 asphyxiation, several immediate early genes were expressed at lower levels in Abcc5(-/-) brains than in wild type brains, suggesting altered glutamate signaling. Our results show that ABCC5 is a general glutamate conjugate and analog transporter that affects the disposition of endogenous metabolites, toxins, and drugs.
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Affiliation(s)
- Robert S Jansen
- From the Division of Molecular Oncology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Sunny Mahakena
- From the Division of Molecular Oncology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Marcel de Haas
- From the Division of Molecular Oncology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Piet Borst
- From the Division of Molecular Oncology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Koen van de Wetering
- From the Division of Molecular Oncology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
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32
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N -acetyl-aspartyl-glutamate and inhibition of glutamate carboxypeptidases protects against soman-induced neuropathology. Neurotoxicology 2015; 48:180-91. [DOI: 10.1016/j.neuro.2015.03.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/26/2015] [Accepted: 03/13/2015] [Indexed: 12/31/2022]
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Moffett JR, Arun P, Ariyannur PS, Namboodiri AMA. N-Acetylaspartate reductions in brain injury: impact on post-injury neuroenergetics, lipid synthesis, and protein acetylation. FRONTIERS IN NEUROENERGETICS 2013; 5:11. [PMID: 24421768 PMCID: PMC3872778 DOI: 10.3389/fnene.2013.00011] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 12/09/2013] [Indexed: 12/22/2022]
Abstract
N-Acetylaspartate (NAA) is employed as a non-invasive marker for neuronal health using proton magnetic resonance spectroscopy (MRS). This utility is afforded by the fact that NAA is one of the most concentrated brain metabolites and that it produces the largest peak in MRS scans of the healthy human brain. NAA levels in the brain are reduced proportionately to the degree of tissue damage after traumatic brain injury (TBI) and the reductions parallel the reductions in ATP levels. Because NAA is the most concentrated acetylated metabolite in the brain, we have hypothesized that NAA acts in part as an extensive reservoir of acetate for acetyl coenzyme A synthesis. Therefore, the loss of NAA after TBI impairs acetyl coenzyme A dependent functions including energy derivation, lipid synthesis, and protein acetylation reactions in distinct ways in different cell populations. The enzymes involved in synthesizing and metabolizing NAA are predominantly expressed in neurons and oligodendrocytes, respectively, and therefore some proportion of NAA must be transferred between cell types before the acetate can be liberated, converted to acetyl coenzyme A and utilized. Studies have indicated that glucose metabolism in neurons is reduced, but that acetate metabolism in astrocytes is increased following TBI, possibly reflecting an increased role for non-glucose energy sources in response to injury. NAA can provide additional acetate for intercellular metabolite trafficking to maintain acetyl CoA levels after injury. Here we explore changes in NAA, acetate, and acetyl coenzyme A metabolism in response to brain injury.
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Affiliation(s)
- John R. Moffett
- Neuroscience Program, Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health SciencesBethesda, MD, USA
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34
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Abstract
NAAG (N-acetylaspartylglutamate) is an abundant neuropeptide in the vertebrate nervous system. It is released from synaptic terminals in a calcium-dependent manner and has been shown to act as an agonist at the type II metabotropic glutamate receptor mGluR3. It has been proposed that NAAG may also be released from axons. So far, however, it has remained unclear how NAAG is transported into synaptic or other vesicles before it is secreted. In the present study, we demonstrate that uptake of NAAG and the related peptide NAAG2 (N-acetylaspartylglutamylglutamate) into vesicles depends on the sialic acid transporter sialin (SLC17A5). This was demonstrated using cell lines expressing a cell surface variant of sialin and by functional reconstitution of sialin in liposomes. NAAG uptake into sialin-containing proteoliposomes was detectable in the presence of an active H+-ATPase or valinomycin, indicating that transport is driven by membrane potential rather than H+ gradient. We also show that sialin is most probably the major and possibly only vesicular transporter for NAAG and NAAG2, because ATP-dependent transport of both peptides was not detectable in vesicles isolated from sialin-deficient mice.
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35
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Long PM, Moffett JR, Namboodiri AMA, Viapiano MS, Lawler SE, Jaworski DM. N-acetylaspartate (NAA) and N-acetylaspartylglutamate (NAAG) promote growth and inhibit differentiation of glioma stem-like cells. J Biol Chem 2013; 288:26188-26200. [PMID: 23884408 DOI: 10.1074/jbc.m113.487553] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Metabolic reprogramming is a pathological feature of cancer and a driver of tumor cell transformation. N-Acetylaspartate (NAA) is one of the most abundant amino acid derivatives in the brain and serves as a source of metabolic acetate for oligodendrocyte myelination and protein/histone acetylation or a precursor for the synthesis of the neurotransmitter N-acetylaspartylglutamate (NAAG). NAA and NAAG as well as aspartoacylase (ASPA), the enzyme responsible for NAA degradation, are significantly reduced in glioma tumors, suggesting a possible role for decreased acetate metabolism in tumorigenesis. This study sought to examine the effects of NAA and NAAG on primary tumor-derived glioma stem-like cells (GSCs) from oligodendroglioma as well as proneural and mesenchymal glioblastoma, relative to oligodendrocyte progenitor cells (Oli-Neu). Although the NAA dicarboxylate transporter NaDC3 is primarily thought to be expressed by astrocytes, all cell lines expressed NaDC3 and, thus, are capable of NAA up-take. Treatment with NAA or NAAG significantly increased GSC growth and suppressed differentiation of Oli-Neu cells and proneural GSCs. Interestingly, ASPA was expressed in both the cytosol and nuclei of GSCs and exhibited greatest nuclear immunoreactivity in differentiation-resistant GSCs. Both NAA and NAAG elicited the expression of a novel immunoreactive ASPA species in select GSC nuclei, suggesting differential ASPA regulation in response to these metabolites. Therefore, this study highlights a potential role for nuclear ASPA expression in GSC malignancy and suggests that the use of NAA or NAAG is not an appropriate therapeutic approach to increase acetate bioavailability in glioma. Thus, an alternative acetate source is required.
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Affiliation(s)
- Patrick M Long
- From the Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, Vermont 05405
| | - John R Moffett
- the Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, and
| | - Aryan M A Namboodiri
- the Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, and
| | - Mariano S Viapiano
- the Department of Neurosurgery, Brigham and Women's Hospital, Boston, Massachusetts 02215
| | - Sean E Lawler
- the Department of Neurosurgery, Brigham and Women's Hospital, Boston, Massachusetts 02215
| | - Diane M Jaworski
- From the Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, Vermont 05405,.
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36
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Zhao G, Jin Z, Wang Y, Allewell NM, Tuchman M, Shi D. Structure and function of Escherichia coli RimK, an ATP-grasp fold, L-glutamyl ligase enzyme. Proteins 2013; 81:1847-54. [PMID: 23609986 DOI: 10.1002/prot.24311] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 04/04/2013] [Accepted: 04/09/2013] [Indexed: 11/11/2022]
Abstract
We report herein the crystal structure of Escherichia coli RimK at a resolution of 2.85 Å, an enzyme that catalyzes the post-translational addition of up to 15 C-terminal glutamate residues to ribosomal protein S6. The structure belongs to the ATP-grasp superfamily and is organized as a tetramer, consistent with gel filtration analysis. Each subunit consists of three distinct structural domains and the active site is located in the cleft between these domains. The catalytic reaction appears to occur at the junction between the three domains as ATP binds between the B and C domains, and other substrates bind nearby.
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Affiliation(s)
- Gengxiang Zhao
- Department of Integrative Systems Biology, Center for Genetic Medicine Research, Children's National Medical Center, The George Washington University, Washington, DC, 20010
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Ariyannur PS, Arun P, Barry ES, Andrews-Shigaki B, Bosomtwi A, Tang H, Selwyn R, Grunberg NE, Moffett JR, Namboodiri AM. Do reductions in brainN-acetylaspartate levels contribute to the etiology of some neuropsychiatric disorders? J Neurosci Res 2013; 91:934-42. [DOI: 10.1002/jnr.23234] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/04/2013] [Accepted: 03/13/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Prasanth S. Ariyannur
- Department of Anatomy, Physiology and Genetics; Uniformed Services University of the Health Sciences; Bethesda; Maryland
| | - Peethambaran Arun
- Department of Anatomy, Physiology and Genetics; Uniformed Services University of the Health Sciences; Bethesda; Maryland
| | - Erin S. Barry
- Department of Medical and Clinical Psychology; Uniformed Services University of the Health Sciences; Bethesda; Maryland
| | - Brian Andrews-Shigaki
- Department of Military and Emergency Medicine; Uniformed Services University of the Health Sciences; Bethesda; Maryland
| | - Asamoah Bosomtwi
- Department of Radiology; Uniformed Services University of the Health Sciences; Bethesda; Maryland
| | - Haiying Tang
- Department of Radiology; Uniformed Services University of the Health Sciences; Bethesda; Maryland
| | - Reed Selwyn
- Department of Radiology; Uniformed Services University of the Health Sciences; Bethesda; Maryland
| | - Neil E. Grunberg
- Department of Medical and Clinical Psychology; Uniformed Services University of the Health Sciences; Bethesda; Maryland
| | - John R. Moffett
- Department of Anatomy, Physiology and Genetics; Uniformed Services University of the Health Sciences; Bethesda; Maryland
| | - Aryan M.A. Namboodiri
- Department of Anatomy, Physiology and Genetics; Uniformed Services University of the Health Sciences; Bethesda; Maryland
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Walder KK, Ryan SB, Bzdega T, Olszewski RT, Neale JH, Lindgren CA. Immunohistological and electrophysiological evidence that N-acetylaspartylglutamate is a co-transmitter at the vertebrate neuromuscular junction. Eur J Neurosci 2012; 37:118-29. [PMID: 23134476 DOI: 10.1111/ejn.12027] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 09/18/2012] [Accepted: 09/20/2012] [Indexed: 12/21/2022]
Abstract
Immunohistochemical studies previously revealed the presence of the peptide transmitter N-acetylaspartylglutamate (NAAG) in spinal motor neurons, axons and presumptive neuromuscular junctions (NMJs). At synapses in the central nervous system, NAAG has been shown to activate the type 3 metabotropic glutamate receptor (mGluR3) and is inactivated by an extracellular peptidase, glutamate carboxypeptidase II. The present study tested the hypothesis that NAAG meets the criteria for classification as a co-transmitter at the vertebrate NMJ. Confocal microscopy confirmed the presence of NAAG immunoreactivity and extended the resolution of the peptide's location in the lizard (Anolis carolinensis) NMJ. NAAG was localised to a presynaptic region immediately adjacent to postsynaptic acetylcholine receptors. NAAG was depleted by potassium-induced depolarisation and by electrical stimulation of motor axons. The NAAG receptor, mGluR3, was localised to the presynaptic terminal consistent with NAAG's demonstrated role as a regulator of synaptic release at central synapses. In contrast, glutamate receptors, type 2 metabotropic glutamate receptor (mGluR2) and N-methyl-d-aspartate, were closely associated with acetylcholine receptors in the postsynaptic membrane. Glutamate carboxypeptidase II, the NAAG-inactivating enzyme, was identified exclusively in perisynaptic glial cells. This localisation was confirmed by the loss of immunoreactivity when these cells were selectively eliminated. Finally, electrophysiological studies showed that exogenous NAAG inhibited evoked neurotransmitter release by activating a group II metabotropic glutamate receptor (mGluR2 or mGluR3). Collectively, these data support the conclusion that NAAG is a co-transmitter at the vertebrate NMJ.
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Affiliation(s)
- Kathryn K Walder
- Department of Biology, Grinnell College, Grinnell, IA 50112, USA
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Fawaz MV, Topper M, Firestine SM. The ATP-grasp enzymes. Bioorg Chem 2011; 39:185-91. [PMID: 21920581 PMCID: PMC3243065 DOI: 10.1016/j.bioorg.2011.08.004] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 08/12/2011] [Accepted: 08/13/2011] [Indexed: 12/17/2022]
Abstract
The ATP-grasp enzymes consist of a superfamily of 21 proteins that contain an atypical ATP-binding site, called the ATP-grasp fold. The ATP-grasp fold is comprised of two α+β domains that "grasp" a molecule of ATP between them and members of the family typically have an overall structural design containing three common conserved focal domains. The founding members of the family consist of biotin carboxylase, d-ala-d-ala ligase and glutathione synthetase, all of which catalyze the ATP-assisted reaction of a carboxylic acid with a nucleophile via the formation of an acylphosphate intermediate. While most members of the superfamily follow this mechanistic pathway, studies have demonstrated that two enzymes catalyze only the phosphoryl transfer step and thus are kinases instead of ligases. Members of the ATP-grasp superfamily are found in several metabolic pathways including de novo purine biosynthesis, gluconeogenesis, and fatty acid synthesis. Given the critical nature of these enzymes, researchers have actively sought the development of potent inhibitors of several members of the superfamily as antibacterial and anti-obseity agents. In this review, we will discuss the structure, function, mechanism, and inhibition of the ATP-grasp enzymes.
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Affiliation(s)
| | | | - Steven M. Firestine
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201
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Collard F, Vertommen D, Constantinescu S, Buts L, Van Schaftingen E. Molecular identification of β-citrylglutamate hydrolase as glutamate carboxypeptidase 3. J Biol Chem 2011; 286:38220-38230. [PMID: 21908619 DOI: 10.1074/jbc.m111.287318] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
β-Citrylglutamate (BCG), a compound present in adult testis and in the CNS during the pre- and perinatal periods is synthesized by an intracellular enzyme encoded by the RIMKLB gene and hydrolyzed by an as yet unidentified ectoenzyme. To identify β-citrylglutamate hydrolase, this enzyme was partially purified from mouse testis and characterized. Interestingly, in the presence of Ca(2+), the purified enzyme specifically hydrolyzed β-citrylglutamate and did not act on N-acetyl-aspartylglutamate (NAAG). However, both compounds were hydrolyzed in the presence of Mn(2+). This behavior and the fact that the enzyme was glycosylated and membrane-bound suggested that β-citrylglutamate hydrolase belonged to the same family of protein as glutamate carboxypeptidase 2 (GCP2), the enzyme that catalyzes the hydrolysis of N-acetyl-aspartylglutamate. The mouse tissue distribution of β-citrylglutamate hydrolase was strikingly similar to that of the glutamate carboxypeptidase 3 (GCP3) mRNA, but not that of the GCP2 mRNA. Furthermore, similarly to β-citrylglutamate hydrolase purified from testis, recombinant GCP3 specifically hydrolyzed β-citrylglutamate in the presence of Ca(2+), and acted on both N-acetyl-aspartylglutamate and β-citrylglutamate in the presence of Mn(2+), whereas recombinant GCP2 only hydrolyzed N-acetyl-aspartylglutamate and this, in a metal-independent manner. A comparison of the structures of the catalytic sites of GCP2 and GCP3, as well as mutagenesis experiments revealed that a single amino acid substitution (Asn-519 in GCP2, Ser-509 in GCP3) is largely responsible for GCP3 being able to hydrolyze β-citrylglutamate. Based on the crystal structure of GCP3 and kinetic analysis, we propose that GCP3 forms a labile catalytic Zn-Ca cluster that is critical for its β-citrylglutamate hydrolase activity.
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Affiliation(s)
- François Collard
- de Duve Institute and Université Catholique de Louvain, Avenue Hippocrate 75, B-1200 Brussels, Belgium
| | - Didier Vertommen
- de Duve Institute and Université Catholique de Louvain, Avenue Hippocrate 75, B-1200 Brussels, Belgium
| | - Stefan Constantinescu
- de Duve Institute and Université Catholique de Louvain, Avenue Hippocrate 75, B-1200 Brussels, Belgium
| | - Lieven Buts
- Department of Molecular and Cellular Interactions, Vrije Universiteit Brussel and VIB, 1050 Brussels, Belgium
| | - Emile Van Schaftingen
- de Duve Institute and Université Catholique de Louvain, Avenue Hippocrate 75, B-1200 Brussels, Belgium.
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Group II mGluR agonist LY354740 and NAAG peptidase inhibitor effects on prepulse inhibition in PCP and D-amphetamine models of schizophrenia. Psychopharmacology (Berl) 2011; 216:235-43. [PMID: 21327758 PMCID: PMC3108005 DOI: 10.1007/s00213-011-2200-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2010] [Accepted: 01/25/2011] [Indexed: 01/03/2023]
Abstract
RATIONALE Group II metabotropic glutamate receptor (mGluR) agonists represent a novel approach to the treatment of schizophrenia. Inasmuch as the peptide neurotransmitter N-acetylaspartylglutamate (NAAG) activates these receptors, NAAG peptidase inhibitors conceptually represent a parallel path toward development of new antipsychotic drugs. While group II agonists are effective in several animal models of schizophrenia, they are reported to lack efficacy in moderating the effects of phencyclidine (PCP) on prepulse inhibition of acoustic startle in animal models of sensory processing deficits found in this disorder. OBJECTIVE The objective of this study was to re-examine the efficacy of a group II metabotropic glutamate agonist and NAAG peptidase inhibitors in prepulse inhibition models of schizophrenia across two strains of mice. METHODS The method used was an assay to determine the efficacy of these drugs in moderating the reduction in prepulse inhibition of acoustic startle in mice treated with PCP and D: -amphetamine. RESULTS The group II agonist LY354740 (5 and 10 mg/kg) moderated the effects of PCP on prepulse inhibition of acoustic startle in DBA/2 but not C57BL/6 mice. In contrast, two NAAG peptidase inhibitors, ZJ43 (150 mg/kg) and 2-PMPA (50, 100, and 150 mg/kg), did not significantly affect the PCP-induced reduction in prepulse inhibition in either strain. CONCLUSIONS These data demonstrate that the efficacy of group II agonists in this model of sensory motor processing is strain-specific in mice. The difference between the effects of the group II agonist and the peptidase inhibitors in the DBA/2 mice may relate to the difference in efficacy of NAAG and the agonist at mGluR2.
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Neale JH, Olszewski RT, Zuo D, Janczura KJ, Profaci CP, Lavin KM, Madore JC, Bzdega T. Advances in understanding the peptide neurotransmitter NAAG and appearance of a new member of the NAAG neuropeptide family. J Neurochem 2011; 118:490-8. [PMID: 21644997 DOI: 10.1111/j.1471-4159.2011.07338.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A substantial body of data was reported between 1984 and 2000 demonstrating that the neuropeptide N-acetylaspartylglutamate (NAAG) not only functions as a neurotransmitter but also is the third most prevalent transmitter in the mammalian nervous system behind glutamate and GABA. By 2005, this conclusion was validated further through a series of studies in vivo and in vitro. The primary enzyme responsible for the inactivation of NAAG following its synaptic release had been cloned, characterized and knocked out. Potent inhibitors of this enzyme were developed and their efficacy has been extensively studied in a series of animal models of clinical conditions, including stroke, peripheral neuropathy, traumatic brain injury, inflammatory and neuropathic pain, cocaine addiction, and schizophrenia. Considerable progress also has been made in defining further the mechanism of action of these peptidase inhibitors in elevating synaptic levels of NAAG with the consequent inhibition of transmitter release via the activation of pre-synaptic metabotropic glutamate receptor 3 by this peptide. Very recent discoveries include identification of two different nervous system enzymes that mediate the synthesis of NAAG from N-acetylaspartate and glutamate and the finding that one of these enzymes also mediates the synthesis of a second member of the NAAG family of neuropeptides, N-acetylaspartylglutamylglutamate.
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Affiliation(s)
- Joseph H Neale
- Department of Biology, Georgetown University, Washington, District of Columbia 20057, USA.
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Lodder-Gadaczek J, Becker I, Gieselmann V, Wang-Eckhardt L, Eckhardt M. N-acetylaspartylglutamate synthetase II synthesizes N-acetylaspartylglutamylglutamate. J Biol Chem 2011; 286:16693-706. [PMID: 21454531 DOI: 10.1074/jbc.m111.230136] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
N-Acetylaspartylglutamate (NAAG) is found at high concentrations in the vertebrate nervous system. NAAG is an agonist at group II metabotropic glutamate receptors. In addition to its role as a neuropeptide, a number of functions have been proposed for NAAG, including a role as a non-excitotoxic transport form of glutamate and a molecular water pump. We recently identified a NAAG synthetase (now renamed NAAG synthetase I, NAAGS-I), encoded by the ribosomal modification protein rimK-like family member B (Rimklb) gene, as a member of the ATP-grasp protein family. We show here that a structurally related protein, encoded by the ribosomal modification protein rimK-like family member A (Rimkla) gene, is another NAAG synthetase (NAAGS-II), which in addition, synthesizes the N-acetylated tripeptide N-acetylaspartylglutamylglutamate (NAAG(2)). In contrast, NAAG(2) synthetase activity was undetectable in cells expressing NAAGS-I. Furthermore, we demonstrate by mass spectrometry the presence of NAAG(2) in murine brain tissue and sciatic nerves. The highest concentrations of both, NAAG(2) and NAAG, were found in sciatic nerves, spinal cord, and the brain stem, in accordance with the expression level of NAAGS-II. To our knowledge the presence of NAAG(2) in the vertebrate nervous system has not been described before. The physiological role of NAAG(2), e.g. whether it acts as a neurotransmitter, remains to be determined.
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Affiliation(s)
- Julia Lodder-Gadaczek
- Institute of Biochemistry and Molecular Biology, University of Bonn, D-53115 Bonn, Germany
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Profiling the effects of isocitrate dehydrogenase 1 and 2 mutations on the cellular metabolome. Proc Natl Acad Sci U S A 2011; 108:3270-5. [PMID: 21289278 DOI: 10.1073/pnas.1019393108] [Citation(s) in RCA: 355] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Point mutations of the NADP(+)-dependent isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) occur early in the pathogenesis of gliomas. When mutated, IDH1 and IDH2 gain the ability to produce the metabolite (R)-2-hydroxyglutarate (2HG), but the downstream effects of mutant IDH1 and IDH2 proteins or of 2HG on cellular metabolism are unknown. We profiled >200 metabolites in human oligodendroglioma (HOG) cells to determine the effects of expression of IDH1 and IDH2 mutants. Levels of amino acids, glutathione metabolites, choline derivatives, and tricarboxylic acid (TCA) cycle intermediates were altered in mutant IDH1- and IDH2-expressing cells. These changes were similar to those identified after treatment of the cells with 2HG. Remarkably, N-acetyl-aspartyl-glutamate (NAAG), a common dipeptide in brain, was 50-fold reduced in cells expressing IDH1 mutants and 8.3-fold reduced in cells expressing IDH2 mutants. NAAG also was significantly lower in human glioma tissues containing IDH mutations than in gliomas without such mutations. These metabolic changes provide clues to the pathogenesis of tumors associated with IDH gene mutations.
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