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Caldovic L, Ahn JJ, Andricovic J, Balick VM, Brayer M, Chansky PA, Dawson T, Edwards AC, Felsen SE, Ismat K, Jagannathan SV, Mann BT, Medina JA, Morizono T, Morizono M, Salameh S, Vashist N, Williams EC, Zhou Z, Morizono H. Datamining approaches for examining the low prevalence of N-acetylglutamate synthase deficiency and understanding transcriptional regulation of urea cycle genes. J Inherit Metab Dis 2023. [PMID: 37847851 DOI: 10.1002/jimd.12687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 10/09/2023] [Accepted: 10/10/2023] [Indexed: 10/19/2023]
Abstract
Ammonia, which is toxic to the brain, is converted into non-toxic urea, through a pathway of six enzymatically catalyzed steps known as the urea cycle. In this pathway, N-acetylglutamate synthase (NAGS, EC 2.3.1.1) catalyzes the formation of N-acetylglutamate (NAG) from glutamate and acetyl coenzyme A. NAGS deficiency (NAGSD) is the rarest of the urea cycle disorders, yet is unique in that ureagenesis can be restored with the drug N-carbamylglutamate (NCG). We investigated whether the rarity of NAGSD could be due to low sequence variation in the NAGS genomic region, high NAGS tolerance for amino acid replacements, and alternative sources of NAG and NCG in the body. We also evaluated whether the small genomic footprint of the NAGS catalytic domain might play a role. The small number of patients diagnosed with NAGSD could result from the absence of specific disease biomarkers and/or short NAGS catalytic domain. We screened for sequence variants in NAGS regulatory regions in patients suspected of having NAGSD and found a novel NAGS regulatory element in the first intron of the NAGS gene. We applied the same datamining approach to identify regulatory elements in the remaining urea cycle genes. In addition to the known promoters and enhancers of each gene, we identified several novel regulatory elements in their upstream regions and first introns. The identification of cis-regulatory elements of urea cycle genes and their associated transcription factors holds promise for uncovering shared mechanisms governing urea cycle gene expression and potentially leading to new treatments for urea cycle disorders.
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Affiliation(s)
- Ljubica Caldovic
- Center for Genetic Medicine Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA
- Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
| | - Julie J Ahn
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Jacklyn Andricovic
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Veronica M Balick
- Department of Biochemistry and Molecular Medicine, The George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Mallory Brayer
- Department of Biological Sciences, The George Washington University, Washington, DC, USA
| | - Pamela A Chansky
- The Institute for Biomedical Science, School of Medicine and Health Sciences, George Washington University, Washington, DC, USA
| | - Tyson Dawson
- The Institute for Biomedical Science, School of Medicine and Health Sciences, George Washington University, Washington, DC, USA
- AMPEL BioSolutions LLC, Charlottesville, Virginia, USA
| | - Alex C Edwards
- The Institute for Biomedical Science, School of Medicine and Health Sciences, George Washington University, Washington, DC, USA
- Center for Neuroscience Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA
| | - Sara E Felsen
- The Institute for Biomedical Science, School of Medicine and Health Sciences, George Washington University, Washington, DC, USA
- Center for Neuroscience Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA
| | - Karim Ismat
- Center for Genetic Medicine Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA
- Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
| | - Sveta V Jagannathan
- The Institute for Biomedical Science, School of Medicine and Health Sciences, George Washington University, Washington, DC, USA
| | - Brendan T Mann
- Department of Microbiology, Immunology, and Tropical Medicine, School of Medicine and Health Sciences, George Washington University, Washington, DC, USA
| | - Jacob A Medina
- The Institute for Biomedical Science, School of Medicine and Health Sciences, George Washington University, Washington, DC, USA
| | - Toshio Morizono
- College of Science and Engineering, University of Minnesota, Minneapolis, Minnesota, USA
| | - Michio Morizono
- College of Science and Engineering, University of Minnesota, Minneapolis, Minnesota, USA
| | - Shatha Salameh
- Department of Pharmacology & Physiology, School of Medicine and Health Sciences, George Washington University, Washington, DC, USA
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, USA
| | - Neerja Vashist
- Center for Genetic Medicine Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA
- Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
| | - Emily C Williams
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC, USA
- The George Washington University Cancer Center, School of Medicine and Health Sciences, George Washington University, Washington, DC, USA
| | - Zhe Zhou
- Department of Civil and Environmental Engineering, The George Washington University, Washington, DC, USA
| | - Hiroki Morizono
- Center for Genetic Medicine Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA
- Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
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Unraveling the therapeutic potential of carbamoyl phosphate synthetase 1 (CPS1) in human disease. Bioorg Chem 2022; 130:106253. [DOI: 10.1016/j.bioorg.2022.106253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/23/2022] [Accepted: 11/01/2022] [Indexed: 11/07/2022]
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Fang X, Wu X, Xiang E, Luo F, Li Q, Ma Q, Yuan F, Chen P. Expression profiling of CPS1 in Correa's cascade and its association with gastric cancer prognosis. Oncol Lett 2021; 21:441. [PMID: 33868479 PMCID: PMC8045184 DOI: 10.3892/ol.2021.12702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 02/26/2021] [Indexed: 12/13/2022] Open
Abstract
Carbamoyl phosphate synthetase 1 (CPS1), which is the antigen for the hepatocyte paraffin 1 antibody, exhibits focal immunoreactivity in adenocarcinoma from the gastrointestinal tract, but its expression profiles and roles in gastric cancer (GC) remain largely unknown. The present study aimed to determine the expression pattern and prognostic value of CPS1 in Correa's cascade using tissues from 32 patients with chronic atrophic gastritis with intestinal metaplasia (IM), 62 patients with low- or high-grade intraepithelial neoplasia (IN) and 401 patients with GC. The expression of CPS1 was diffuse and strongly positive in 32 cases (100%) of IM of the glandular epithelium, and gradually downregulated in Correa's cascade, with a strongly positive ratio of 21 (70%) in low-grade IN and 4 (12.5%) in high-grade IN. The levels of CPS1 expression were significantly higher in diffuse-type GC, with 37 (26%) cases strongly positive for CPS1, compared with 14 (8%) in intestinal-type and 11 (13%) cases in mixed-type GC. In intestinal-type GC, CPS1 expression was completely lost in 107 (62%) of cases, which was associated with an advanced Tumor-Node-Metastasis stage (P=0.031) and depth of invasion (P=0.037). Kaplan-Meier analysis suggested that low CPS1 expression levels were independently associated with a short overall survival (OS) time in the three types of GC (P<0.001 in intestinal-type, P=0.003 in diffuse-type and P=0.018 in mixed-type GC). Furthermore, low levels of CPS1 mRNA and high methylation levels in the CPS1 promoter were associated with a short OS time in patients with GC. These results suggested that the expression of CPS1 was progressively downregulated in Correa's cascade, and that CPS1 may serve as a prognostic marker for patients with GC, regardless of tumor type.
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Affiliation(s)
- Xuqian Fang
- Department of Pathology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201821, P.R. China
| | - Xiaoqiong Wu
- Department of Clinical Laboratory, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201821, P.R. China
| | - Enfei Xiang
- Clinical Research Center, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201821, P.R. China
| | - Fangxiu Luo
- Department of Pathology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201821, P.R. China
| | - Qinqin Li
- Department of Pathology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201821, P.R. China
| | - Qianchen Ma
- Department of Pathology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201821, P.R. China
| | - Fei Yuan
- Department of Pathology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201821, P.R. China
| | - Peizhan Chen
- Clinical Research Center, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201821, P.R. China
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Soria LR, Brunetti-Pierri N. Ammonia and autophagy: An emerging relationship with implications for disorders with hyperammonemia. J Inherit Metab Dis 2019; 42:1097-1104. [PMID: 30671986 DOI: 10.1002/jimd.12061] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 01/16/2019] [Indexed: 12/11/2022]
Abstract
(Macro)autophagy/autophagy is a highly regulated lysosomal degradative process by which cells recycle their own nutrients, such as amino acids and other metabolites, to be reused in different biosynthetic pathways. Ammonia is a diffusible compound generated daily from catabolism of nitrogen-containing molecules and from gastrointestinal microbiome. Ammonia homeostasis is tightly controlled in humans and ammonia is efficiently converted by the healthy liver into non-toxic urea (through ureagenesis) and glutamine (through glutamine synthetase). Impaired ammonia detoxification leads to systemic hyperammonemia, a life-threatening condition resulting in detrimental effects on central nervous system. Here, we review current understanding on the role of ammonia in modulation of autophagy and the potential implications in the pathogenesis and treatment of disorders with hyperammonemia.
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Affiliation(s)
- Leandro R Soria
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Nicola Brunetti-Pierri
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
- Department of Translational Medicine, Federico II University, Naples, Italy
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5
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Chen Z, Tang N, Wang X, Chen Y. The activity of the carbamoyl phosphate synthase 1 promoter in human liver-derived cells is dependent on hepatocyte nuclear factor 3-beta. J Cell Mol Med 2017; 21:2036-2045. [PMID: 28272778 PMCID: PMC5571533 DOI: 10.1111/jcmm.13123] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 01/13/2017] [Indexed: 01/15/2023] Open
Abstract
Carbamoyl phosphate synthase 1 (CPS1) is the rate‐limiting enzyme in the first step of the urea cycle and an indispensable enzyme in the metabolism of human liver. However, CPS1 epigenetic regulation involves promoter analysis and the role of liver‐enriched transcription factors (LETFs), which is not fully elucidated. In this work, the promoter region of hCPS1 gene was cloned, and its activity was investigated. An LETF, hepatocyte nuclear factor 3‐beta (HNF3β), was found to promote the transcriptional expression of CPS1 in liver‐derived cell lines. In addition, dual‐luciferase reporter assay shows that the essential binding sites of the HNF3β may exist in the oligonucleotide −70 nt to +73 nt. Two putative binding sites are available for HNF3β. Mutation analysis results show that the binding site 2 of HNF3β was effective, and the transcriptional activity of CPS1 promoter significantly decreased after mutation. Electrophoretic mobile shift assay (EMSA) and ChIP assay confirmed that HNF3β can interact with the binding site in the CPS1 promoter region of −70 nt to +73 nt promoter region in vivo and in vitro to regulate the transcription of CPS1. Moreover, HNF3β overexpression enhanced the transcription of CPS1 and consequently improved the mRNA and protein levels of CPS1, whereas the knockdown of HNF3β showed the opposite effects. Finally, urea production in cells was measured, and ammonia detoxification improved significantly in cells after transfection with HNF3β. HNF3β plays a vital role in regulation of CPS1 gene and could promote the metabolism of ammonia by regulating CPS1 expression.
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Affiliation(s)
- Zhanfei Chen
- Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, Fuzhou, China
| | - Nanhong Tang
- Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, Fuzhou, China.,Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Research Center for Molecular Medicine, Fujian Medical University, Fuzhou, China
| | - Xiaoqian Wang
- Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, Fuzhou, China
| | - Yanling Chen
- Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, Fuzhou, China.,Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Research Center for Molecular Medicine, Fujian Medical University, Fuzhou, China
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Qiu F, Huang J, Sui M. Targeting arginine metabolism pathway to treat arginine-dependent cancers. Cancer Lett 2015; 364:1-7. [DOI: 10.1016/j.canlet.2015.04.020] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/28/2015] [Accepted: 04/19/2015] [Indexed: 01/01/2023]
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7
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Shiue SC, Huang MZ, Tsai TF, Chang AC, Choo KB, Huang CJ, Su TS. Expression profile and down-regulation of argininosuccinate synthetase in hepatocellular carcinoma in a transgenic mouse model. J Biomed Sci 2015; 22:10. [PMID: 25616743 PMCID: PMC4308890 DOI: 10.1186/s12929-015-0114-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 01/12/2015] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Argininosuccinate synthetase (ASS) participates in urea and nitric oxide production and is a rate-limiting enzyme in arginine biosynthesis. Regulation of ASS expression appears complex and dynamic. In addition to transcriptional regulation, a novel post-transcriptional regulation affecting nuclear precursor RNA stability has been reported. Moreover, many cancers, including hepatocellular carcinoma (HCC), have been found not to express ASS mRNA; therefore, they are auxotrophic for arginine. To study when and where ASS is expressed and whether post-transcriptional regulation is undermined in particular temporal and spatial expression and in pathological events such as HCC, we set up a transgenic mouse system with modified BAC (bacterial artificial chromosome) carrying the human ASS gene tagged with an EGFP reporter. RESULTS We established and characterized the transgenic mouse models based on the use of two BAC-based EGFP reporter cassettes: a transcription reporter and a transcription/post-transcription coupled reporter. Using such a transgenic mouse system, EGFP fluorescence pattern in E14.5 embryo was examined. Profiles of fluorescence and that of Ass RNA in in situ hybridization were found to be in good agreement in general, yet our system has the advantages of sensitivity and direct fluorescence visualization. By comparing expression patterns between mice carrying the transcription reporter and those carrying the transcription/post-transcription couple reporter, a post-transcriptional up-regulation of ASS was found around the ventricular zone/subventricular zone of E14.5 embryonic brain. In the EGFP fluorescence pattern and mRNA level in adult tissues, tissue-specific regulation was found to be mainly controlled at transcriptional initiation. Furthermore, strong EGFP expression was found in brain regions of olfactory bulb, septum, habenular nucleus and choroid plexus of the young transgenic mice. On the other hand, in crossing to hepatitis B virus X protein (HBx)-transgenic mice, the Tg (ASS-EGFP, HBx) double transgenic mice developed HCC in which ASS expression was down-regulated, as in clinical samples. CONCLUSIONS The BAC transgenic mouse model described is a valuable tool for studying ASS gene expression. Moreover, this mouse model is a close reproduction of clinical behavior of ASS in HCC and is useful in testing arginine-depleting agents and for studies of the role of ASS in tumorigenesis.
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Affiliation(s)
- Shih-Chang Shiue
- Institute of Microbiology & Immunology, National Yang-Ming University, Taipei, Taiwan.
| | - Miao-Zeng Huang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, 112, Taiwan.
| | - Ting-Fen Tsai
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan.
| | - Alice Chien Chang
- Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan.
| | - Kong Bung Choo
- Department of Preclinical Sciences, Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Selangor, Malaysia.
- Centre for Stem Cell Research, Universiti Tunku Abdul Rahman, Selangor, Malaysia.
| | - Chiu-Jung Huang
- Department of Animal Science, Chinese Culture University, Taipei, Taiwan.
- Graduate Institute of Biotechnology, Chinese Culture University, Taipei, Taiwan.
| | - Tsung-Sheng Su
- Institute of Microbiology & Immunology, National Yang-Ming University, Taipei, Taiwan.
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, 112, Taiwan.
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan.
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8
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Shiue SC, Huang MZ, Su TS. A transgenic approach to study argininosuccinate synthetase gene expression. J Biomed Sci 2014; 21:42. [PMID: 24884799 PMCID: PMC4025196 DOI: 10.1186/1423-0127-21-42] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 04/21/2014] [Indexed: 12/04/2022] Open
Abstract
Background Argininosuccinate synthetase (ASS) participates in urea, nitric oxide and arginine production. Besides transcriptional regulation, a post-transcriptional regulation affecting nuclear precursor RNA stability has been reported. To study whether such post-transcriptional regulation underlines particular temporal and spatial ASS expression, and to investigate how human ASS gene behaves in a mouse background, a transgenic mouse system using a modified bacterial artificial chromosome carrying the human ASS gene tagged with EGFP was employed. Results Two lines of ASS-EGFP transgenic mice were generated: one with EGFP under transcriptional control similar to that of the endogenous ASS gene, another with EGFP under both transcriptional and post-transcriptional regulation as that of the endogenous ASS mRNA. EGFP expression in the liver, the organ for urea production, and in the intestine and kidney that are responsible for arginine biosynthesis, was examined. Organs taken from embryos E14.5 stage to young adult were examined under a fluorescence microscope either directly or after cryosectioning. The levels of EGFP and endogenous mouse Ass mRNAs were also quantified by S1 nuclease mapping. EGFP fluorescence and EGFP mRNA levels in both the liver and kidney were found to increase progressively from embryonic stage toward birth. In contrast, EGFP expression in the intestine was higher in neonates and started to decline at about 3 weeks after birth. Comparison between the EGFP profiles of the two transgenic lines indicated the developmental and tissue-specific regulation was mainly controlled at the transcriptional level. The ASS transgene was of human origin. EGFP expression in the liver followed essentially the mouse Ass pattern as evidenced by zonation distribution of fluorescence and the level of EGFP mRNA at birth. However, in the small intestine, Ass mRNA level declined sharply at 3 week of age, and yet substantial EGFP mRNA was still detectable at this stage. Thus, the time course of EGFP expression in the transgenic mice resembled that of the human ASS gene. Conclusions We demonstrate that the transgenic mouse system reported here has the merit of sensitivity and direct visualization advantage, and is ideal for annotating temporal and spatial expression profiles and the regulation mode of the ASS gene.
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Affiliation(s)
| | | | - Tsung-Sheng Su
- Institute of Microbiology & Immunology, National Yang-Ming University, 112 Taipei, Taiwan.
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9
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Huang Z, Wang TS, Zhao YC, Zuo RJ, Deng WB, Chi YJ, Yang ZM. Cyclic adenosine monophosphate-induced argininosuccinate synthase 1 expression is essential during mouse decidualization. Mol Cell Endocrinol 2014; 388:20-31. [PMID: 24556046 DOI: 10.1016/j.mce.2014.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 01/23/2014] [Accepted: 02/11/2014] [Indexed: 12/30/2022]
Abstract
L-Arginine (L-Arg), a conditional essential amino acid in adults, has been shown to enhance pregnancy outcome. Argininosuccinate synthase (Ass1) and argininosuccinate lyase (Asl) are the key enzyme for L-Arginine (L-Arg) biosynthesis. Based our microarray analysis, Ass1 expression is upregulated significantly at implantation site on day 5 of pregnancy compared to that at inter-implantation site. However, the expression, regulation and function of Ass1 during early pregnancy remain unknown. Here we found that Ass1 is highly expressed in mouse decidua and uterine stromal cells undergoing decidualization, and Asl is weakly expressed in mouse decidua and uterine stromal cells undergoing decidualization. α-Methyl-DL-aspartic acid (MDLA), a specific inhibitor for Ass1, can significantly increase the rate of embryonic reabsorption. Under in vitro induced decidualization, MDLA clearly inhibits the expression of decidual/trophoblast prolactin-related protein (Dtprp), a marker for decidualization in mice. Only Ass1 expression is induced by cAMP through PKA/p-Creb signaling pathway. Results from our cell culture models further indicates that the high level of L-Arg enhances stromal proliferation, while enzymatic activity or Ass1 expression level is essential to determine the magnitude of both mouse and human decidualization. Interestingly, L-Arg at high concentration down-regulates Ass1 and Asl expression by negative feedback to maintain L-Arg homeostasis. These findings highlight that cAMP-induced Ass1 expression is important in controlling the magnitude of decidualization through regulating L-Arg level.
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Affiliation(s)
- Zhu Huang
- School of Life Science, Xiamen University, Xiamen 361005, China; College of Life Science, Anqing Normal University, Anqing 246011, China
| | - Tong-Song Wang
- School of Science, Shantou University, Shantou 515000, China
| | - Yue-Chao Zhao
- School of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Ru-Juan Zuo
- School of Life Science, Xiamen University, Xiamen 361005, China
| | - Wen-Bo Deng
- School of Life Science, Xiamen University, Xiamen 361005, China
| | - Yu-Jing Chi
- School of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Zeng-Ming Yang
- School of Science, Shantou University, Shantou 515000, China; College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
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10
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Heibel SK, Lopez GY, Panglao M, Sodha S, Mariño-Ramírez L, Tuchman M, Caldovic L. Transcriptional regulation of N-acetylglutamate synthase. PLoS One 2012; 7:e29527. [PMID: 22383952 PMCID: PMC3287996 DOI: 10.1371/journal.pone.0029527] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 11/30/2011] [Indexed: 01/13/2023] Open
Abstract
The urea cycle converts toxic ammonia to urea within the liver of mammals. At least 6 enzymes are required for ureagenesis, which correlates with dietary protein intake. The transcription of urea cycle genes is, at least in part, regulated by glucocorticoid and glucagon hormone signaling pathways. N-acetylglutamate synthase (NAGS) produces a unique cofactor, N-acetylglutamate (NAG), that is essential for the catalytic function of the first and rate-limiting enzyme of ureagenesis, carbamyl phosphate synthetase 1 (CPS1). However, despite the important role of NAGS in ammonia removal, little is known about the mechanisms of its regulation. We identified two regions of high conservation upstream of the translation start of the NAGS gene. Reporter assays confirmed that these regions represent promoter and enhancer and that the enhancer is tissue specific. Within the promoter, we identified multiple transcription start sites that differed between liver and small intestine. Several transcription factor binding motifs were conserved within the promoter and enhancer regions while a TATA-box motif was absent. DNA-protein pull-down assays and chromatin immunoprecipitation confirmed binding of Sp1 and CREB, but not C/EBP in the promoter and HNF-1 and NF-Y, but not SMAD3 or AP-2 in the enhancer. The functional importance of these motifs was demonstrated by decreased transcription of reporter constructs following mutagenesis of each motif. The presented data strongly suggest that Sp1, CREB, HNF-1, and NF-Y, that are known to be responsive to hormones and diet, regulate NAGS transcription. This provides molecular mechanism of regulation of ureagenesis in response to hormonal and dietary changes.
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Affiliation(s)
- Sandra Kirsch Heibel
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, D. C., United States of America
- Molecular and Cellular Biology Program, University of Maryland, College Park, Maryland, United States of America
| | - Giselle Yvette Lopez
- Department of Pathology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Maria Panglao
- The George Washington University School of Medicine and Health Sciences, Washington, D. C., United States of America
| | - Sonal Sodha
- Johns Hopkins School of Medicine in Baltimore, Maryland, United States of America
| | - Leonardo Mariño-Ramírez
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mendel Tuchman
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, D. C., United States of America
| | - Ljubica Caldovic
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, D. C., United States of America
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Kuo MT, Savaraj N, Feun LG. Targeted cellular metabolism for cancer chemotherapy with recombinant arginine-degrading enzymes. Oncotarget 2011; 1:246-51. [PMID: 21152246 PMCID: PMC2998341 DOI: 10.18632/oncotarget.135] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
It has been shown that a subset of human cancers, notably, melanoma and hepatocellular carcinoma (HCC) are auxotrophic for arginine (Arg), because they do not express argininosuccinate synthetase (ASS), the rate-limiting enzyme for the biosynthesis of arginine from citrulline. These ASS-negative cancer cells require Arg from extracellular sources for survival. When they are exposed to recombinant Arg-degrading enzymes, e.g. arginine deiminase (ADI) or arginase, they die because of Arg starvation; whereas normal cells which express ASS are able to survive. A pegylated ADI (ADI-PEG20) has been developed for clinical trials for advanced melanoma and HCC; and favorable results have been obtained. ADI-PEG20 treatment induces autophagy in auxotrophic cancer cells leading to cell death. Clinical studies in melanoma patients show that re-expression of ASS is associated with ADI-PEG20 resistance. ADI-PEG20 treatment down-regulates the expression of HIF-1α but up-regulates c-Myc in culture melanoma cells. Induction of ASS by ADI-PEG20 involves positive regulators c-Myc and Sp4 and negative regulator HIF1α. Since both HIF-1α and c-Myc play important roles in cancer cell energy metabolism, together these results suggest that targeted cancer cell metabolism through modulation of HIF-1α and c-Myc expression may improve the efficacy of ADI-PEG20 in treating Arg auxotrophic tumors.
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Affiliation(s)
- Macus Tien Kuo
- Department of Molecular Pathology, The University of Texas M. D. Anderson Cancer Center, Houston, USA.
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Walters MW, Wallace KB. Urea cycle gene expression is suppressed by PFOA treatment in rats. Toxicol Lett 2010; 197:46-50. [PMID: 20452409 DOI: 10.1016/j.toxlet.2010.04.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 04/27/2010] [Accepted: 04/28/2010] [Indexed: 11/28/2022]
Abstract
Perfluorooctanoic acid (PFOA), with an array of industrial uses, is one of the most common perfluoroalkyl acids. Resistance to biological degradation and a global distribution are characteristics that have caused PFOA to become a frequent subject of toxicological studies. PFOA treatment in rodents causes peroxisome proliferation, mitochondrial biogenesis, and transactivation of PPARs. Prior work has shown urea cycle gene expression to be reduced in mice by another PPARalpha ligand, WY14643. In light of these findings, the aim of our investigation was to determine if PFOA treatment in rats alters expression of genes responsible for ureogenesis. 30 mg/kg of PFOA was administered to adult male Sprague-Dawley rats via oral gavage for 28 days and their livers were harvested. Gene transcription was measured using real time PCR and protein expression was determined through western blotting. We observed a decrease in mRNA for the coordinately expressed urea cycle genes Cps1, Ass1, and Asl; mRNA of the ammonia generating Gls2 was also reduced. Protein amounts for CPS1, ASS1, and OTC were all decreased in the PFOA treated rats, and interestingly there was an increase in the amount of S133 phosphorylated CREB, which is a regulator of urea cycle gene transcription. We conclude that the transactivation of PPARalpha by PFOA leads to a metabolic shift that favors the catabolism of lipids over proteins, thereby suppressing urea cycle gene expression. Our findings provide further evidence of the effect of PFOA on intermediary metabolism in rodents and add valuable information in assessing the potential risks of PFOA exposure.
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Affiliation(s)
- M W Walters
- Department of Biochemistry and Molecular Biology, University of Minnesota Medical School, Duluth, MN 55812, United States.
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Tsai WB, Aiba I, Lee SY, Feun L, Savaraj N, Kuo MT. Resistance to arginine deiminase treatment in melanoma cells is associated with induced argininosuccinate synthetase expression involving c-Myc/HIF-1alpha/Sp4. Mol Cancer Ther 2010; 8:3223-33. [PMID: 19934275 DOI: 10.1158/1535-7163.mct-09-0794] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Arginine deiminase (ADI)-based arginine depletion is a novel strategy under clinical trials for the treatment of malignant melanoma with promising results. The sensitivity of melanoma to ADI treatment is based on its auxotrophy for arginine due to a lack of argininosuccinate synthetase (AS) expression, the rate-limiting enzyme for the de novo biosynthesis of arginine. We show here that AS expression can be transcriptionally induced by ADI in melanoma cell lines A2058 and SK-MEL-2 but not in A375 cells, and this inducibility was correlated with resistance to ADI treatment. The proximal region of the AS promoter contains an E-box that is recognized by c-Myc and HIF-1alpha and a GC-box by Sp4. Through ChIP assays, we showed that under noninduced conditions, the E-box was bound by HIF-1alpha in all the three melanoma cell lines. Under arginine depletion conditions, HIF-1alpha was replaced by c-Myc in A2058 and SK-MEL-2 cells but not in A375 cells. Sp4 was constitutively bound to the GC-box regardless of arginine availability in all three cell lines. Overexpressing c-Myc by transfection upregulated AS expression in A2058 and SK-MEL-2 cells, whereas cotransfection with HIF-1alpha suppressed c-Myc-induced AS expression. These results suggest that regulation of AS expression involves interplay among positive transcriptional regulators c-Myc and Sp4, and negative regulator HIF-1alpha that confers resistance to ADI treatment in A2058 and SK-MEL-2 cells. Inability of AS induction in A375 cells under arginine depletion conditions was correlated by the failure of c-Myc to interact with the AS promoter.
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Affiliation(s)
- Wen-Bin Tsai
- Department of Molecular Pathology, Unit 951, The University of Texas M. D. Anderson Cancer Center, 7435 Fannin Street, Houston, Texas 77030, USA
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