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Shin KWD, Atalay MV, Cetin-Atalay R, O'Leary EM, Glass ME, Szafran JCH, Woods PS, Meliton AY, Shamaa OR, Tian Y, Mutlu GM, Hamanaka RB. mTOR signaling regulates multiple metabolic pathways in human lung fibroblasts after TGF-β and in pulmonary fibrosis. Am J Physiol Lung Cell Mol Physiol 2025; 328:L215-L228. [PMID: 39745695 DOI: 10.1152/ajplung.00189.2024] [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: 06/20/2024] [Revised: 11/25/2024] [Accepted: 12/11/2024] [Indexed: 01/24/2025] Open
Abstract
Idiopathic pulmonary fibrosis is a fatal disease characterized by the transforming growth factor (TGF-β)-dependent activation of lung fibroblasts, leading to excessive deposition of collagen proteins and progressive replacement of healthy lungs with scar tissue. We and others have shown that TGF-β-mediated activation of the mechanistic target of rapamycin complex 1 (mTORC1) and downstream upregulation of activating transcription factor 4 (ATF4) promotes metabolic reprogramming in lung fibroblasts characterized by upregulation of the de novo synthesis of glycine, the most abundant amino acid found in collagen protein. Whether mTOR and ATF4 regulate other metabolic pathways in lung fibroblasts has not been explored. Here, we used RNA sequencing to determine how both ATF4 and mTOR regulate gene expression in human lung fibroblasts following TGF-β. We found that ATF4 primarily regulates enzymes and transporters involved in amino acid homeostasis as well as aminoacyl-tRNA synthetases. mTOR inhibition resulted not only in the loss of ATF4 target gene expression but also in the reduced expression of glycolytic enzymes and mitochondrial electron transport chain subunits. Analysis of TGF-β-induced changes in cellular metabolite levels confirmed that ATF4 regulates amino acid homeostasis in lung fibroblasts, whereas mTOR also regulates glycolytic and TCA cycle metabolites. We further analyzed publicly available single-cell RNA-seq datasets and found increased expression of ATF4 and mTOR-regulated genes in pathologic fibroblast populations from the lungs of patients with IPF. Our results provide insight into the mechanisms of metabolic reprogramming in lung fibroblasts and highlight novel ATF4 and mTOR-dependent pathways that may be targeted to inhibit fibrotic processes.NEW & NOTEWORTHY Here, we used transcriptomic and metabolomic approaches to develop a more complete understanding of the role that mTOR, and its downstream effector ATF4, play in promoting metabolic reprogramming in lung fibroblasts. We identify novel metabolic pathways that may promote pathologic phenotypes, and we provide evidence from single-cell RNA-seq datasets that similar metabolic reprogramming occurs in patient lungs.
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Affiliation(s)
- Kun Woo D Shin
- Department of Medicine, Section of Pulmonary and Critical Care Medicine, The University of Chicago, Chicago, Illinois, United States
| | - M Volkan Atalay
- Department of Information Systems and Supply Chain Management, Loyola University Chicago, Chicago, Illinois, United States
| | - Rengul Cetin-Atalay
- Department of Medicine, Section of Pulmonary and Critical Care Medicine, The University of Chicago, Chicago, Illinois, United States
| | - Erin M O'Leary
- Department of Medicine, Section of Pulmonary and Critical Care Medicine, The University of Chicago, Chicago, Illinois, United States
| | - Mariel E Glass
- Department of Medicine, Section of Pulmonary and Critical Care Medicine, The University of Chicago, Chicago, Illinois, United States
| | - Jennifer C Houpy Szafran
- Department of Medicine, Section of Pulmonary and Critical Care Medicine, The University of Chicago, Chicago, Illinois, United States
| | - Parker S Woods
- Department of Medicine, Section of Pulmonary and Critical Care Medicine, The University of Chicago, Chicago, Illinois, United States
| | - Angelo Y Meliton
- Department of Medicine, Section of Pulmonary and Critical Care Medicine, The University of Chicago, Chicago, Illinois, United States
| | - Obada R Shamaa
- Department of Medicine, Section of Pulmonary and Critical Care Medicine, The University of Chicago, Chicago, Illinois, United States
| | - Yufeng Tian
- Department of Medicine, Section of Pulmonary and Critical Care Medicine, The University of Chicago, Chicago, Illinois, United States
| | - Gökhan M Mutlu
- Department of Medicine, Section of Pulmonary and Critical Care Medicine, The University of Chicago, Chicago, Illinois, United States
| | - Robert B Hamanaka
- Department of Medicine, Section of Pulmonary and Critical Care Medicine, The University of Chicago, Chicago, Illinois, United States
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Dentel B, Angeles-Perez L, Flores AY, Lei K, Ren C, Sanchez AP, Tsai PT. Neuronal cell type specific roles for Nprl2 in neurodevelopmental disorder-relevant behaviors. Neurobiol Dis 2025; 205:106790. [PMID: 39765274 DOI: 10.1016/j.nbd.2025.106790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 01/03/2025] [Accepted: 01/03/2025] [Indexed: 01/13/2025] Open
Abstract
Loss of function in the subunits of the GTPase-activating protein (GAP) activity toward Rags-1 (GATOR1) complex, an amino-acid sensitive negative regulator of the mechanistic target of rapamycin complex 1 (mTORC1), is implicated in both genetic familial epilepsies and Neurodevelopmental Disorders (NDDs) (Baldassari et al., 2018). Previous studies have found seizure phenotypes and increased activity resulting from conditional deletion of GATOR1 function from forebrain excitatory neurons (Yuskaitis et al., 2018; Dentel et al., 2022); however, studies focused on understanding mechanisms contributing to NDD-relevant behaviors are lacking, especially studies understanding the contributions of GATOR1's critical GAP catalytic subunit, nitrogen permease regulator like-2 (Nprl2). Given the clinical phenotypes observed in patients with Nprl2 mutations, in this study, we sought to investigate the neuronal cell type contributions of Nprl2 to NDD behaviors. We conditionally deleted Nprl2 broadly in most neurons (Synapsin1cre), in inhibitory neurons only (Vgatcre), and in Purkinje cells within the cerebellum (L7cre). Broad neuronal deletion of Nprl2 resulted in seizures, social and learning deficits, and hyperactivity. In contrast, deleting Nprl2 from inhibitory neurons led to increased motor learning, hyperactive behavior, in addition to social and learning deficits. Lastly, Purkinje cell (PC) loss of Nprl2 also led to learning and social deficits but did not affect locomotor activity. These phenotypes enhance understanding of the spectrum of disease found in human populations with GATOR1 loss of function and highlight the significance of distinct cellular populations to NDD-related behaviors. SIGNIFICANCE STATEMENT: We aim to elucidate the neuronal-specific contributions of nitrogen permease regulator like-2 (Nprl2) to its neurodevelopmental disorder (NDD)-relevant phenotypes. We conditionally deleted Nprl2 broadly in neurons (Syn1cre), in inhibitory neurons (Vgatcre), and in cerebellar Purkinje cells (L7cre). We identify seizures only in the Syn1cre conditional mutant (cKO); hyperactivity, learning difficulties, social deficits, and impulsivity in the Syn1cre and Vgatcre cKOs; and social deficits, and fear learning deficits in L7cre cKOs. To our knowledge, we are the first to describe the behavioral contributions of Nprl2's function across multiple cell types. Our findings highlight both critical roles for Nprl2 in learning and behavior and also distinct contributions of select neuronal populations to these NDD-relevant behaviors.
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Affiliation(s)
- Brianne Dentel
- The University of Texas Southwestern Medical Center, Department of Neurology, Dallas, TX, United States of America
| | - Lidiette Angeles-Perez
- The University of Texas Southwestern Medical Center, Department of Neurology, Dallas, TX, United States of America
| | - Abigail Y Flores
- The University of Texas Southwestern Medical Center, Department of Neurology, Dallas, TX, United States of America
| | - Katherine Lei
- The University of Texas Southwestern Medical Center, Department of Neurology, Dallas, TX, United States of America
| | - Chongyu Ren
- The University of Texas Southwestern Medical Center, Department of Neurology, Dallas, TX, United States of America
| | - Andrea Pineda Sanchez
- The University of Texas Southwestern Medical Center, Department of Neurology, Dallas, TX, United States of America
| | - Peter T Tsai
- The University of Texas Southwestern Medical Center, Department of Neurology, Dallas, TX, United States of America; The University of Texas Southwestern Medical Center, Department of Psychiatry, Dallas, TX, United States of America; The University of Texas Southwestern Medical Center, Department of Pediatrics, Dallas, TX, United States of America; The University of Texas Southwestern Medical Center, Department of Neuroscience; O'Donnell Brain Institute, Dallas, TX, United States of America.
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3
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Chuang JY, Kuo HH, Wang PH, Su CJ, Yih LH. NPRL2 is required for proliferation of oncogenic Ras-transformed bronchial epithelial cells. Cell Div 2024; 19:22. [PMID: 38915098 PMCID: PMC11197203 DOI: 10.1186/s13008-024-00126-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 06/18/2024] [Indexed: 06/26/2024] Open
Abstract
Nitrogen permease regulator-like 2 (NPRL2/TUSC4) is known to exert both tumor-suppressing and oncogenic effects in different types of cancers, suggesting that its actions are context dependent. Here, we delineated the molecular and functional effects of NPRL2 in malignantly transformed bronchial epithelial cells. To do so, we depleted NPRL2 in oncogenic HRas-transduced and malignantly transformed human bronchial epithelial (BEAS2B), Ras-AI-T2 cells. Intriguingly, depletion of NPRL2 in these cells induced activation of mTORC1 downstream signaling, inhibited autophagy, and impaired Ras-AI-T2 cell proliferation both in vitro and in vivo. These results suggest that NPRL2 is required for oncogenic HRas-induced cell transformation. Depletion of NPRL2 increased levels of the DNA damage marker γH2AX, the cell cycle inhibitors p21 and p27, and the apoptosis marker cleaved-PARP. These NPRL2-depleted cells first accumulated at G1 and G2, and later exhibited signs of mitotic catastrophe, which implied that NPRL2 depletion may be detrimental to oncogenic HRas-transformed cells. Additionally, NPRL2 depletion reduced heat shock factor 1/heat shock element- and NRF2/antioxidant response element-directed luciferase reporter activities in Ras-AI-T2 cells, indicating that NPRL2 depletion led to the suppression of two key cytoprotective processes in oncogenic HRas-transformed cells. Overall, our data suggest that oncogenic HRas-transduced and malignantly transformed cells may depend on NPRL2 for survival and proliferation, and depletion of NPRL2 also induces a stressed state in these cells.
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Affiliation(s)
- Jing-Yuan Chuang
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan
| | - Hsiao-Hui Kuo
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 115, Taiwan
| | - Pei-Han Wang
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 115, Taiwan
| | - Chih-Jou Su
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 115, Taiwan
| | - Ling-Huei Yih
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 115, Taiwan.
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Muller M, Bélanger J, Hadj-Aissa I, Zhang C, Sephton CF, Dutchak PA. GATOR1 Mutations Impair PI3 Kinase-Dependent Growth Factor Signaling Regulation of mTORC1. Int J Mol Sci 2024; 25:2068. [PMID: 38396745 PMCID: PMC10889792 DOI: 10.3390/ijms25042068] [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: 01/22/2024] [Revised: 02/05/2024] [Accepted: 02/07/2024] [Indexed: 02/25/2024] Open
Abstract
GATOR1 (GAP Activity TOward Rag 1) is an evolutionarily conserved GTPase-activating protein complex that controls the activity of mTORC1 (mammalian Target Of Rapamycin Complex 1) in response to amino acid availability in cells. Genetic mutations in the GATOR1 subunits, NPRL2 (nitrogen permease regulator-like 2), NPRL3 (nitrogen permease regulator-like 3), and DEPDC5 (DEP domain containing 5), have been associated with epilepsy in humans; however, the specific effects of these mutations on GATOR1 function and mTORC1 regulation are not well understood. Herein, we report that epilepsy-linked mutations in the NPRL2 subunit of GATOR1, NPRL2-L105P, -T110S, and -D214H, increase basal mTORC1 signal transduction in cells. Notably, we show that NPRL2-L105P is a loss-of-function mutation that disrupts protein interactions with NPRL3 and DEPDC5, impairing GATOR1 complex assembly and resulting in high mTORC1 activity even under conditions of amino acid deprivation. Furthermore, our studies reveal that the GATOR1 complex is necessary for the rapid and robust inhibition of mTORC1 in response to growth factor withdrawal or pharmacological inhibition of phosphatidylinositol-3 kinase (PI3K). In the absence of the GATOR1 complex, cells are refractory to PI3K-dependent inhibition of mTORC1, permitting sustained translation and restricting the nuclear localization of TFEB, a transcription factor regulated by mTORC1. Collectively, our results show that epilepsy-linked mutations in NPRL2 can block GATOR1 complex assembly and restrict the appropriate regulation of mTORC1 by canonical PI3K-dependent growth factor signaling in the presence or absence of amino acids.
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Affiliation(s)
| | | | | | | | | | - Paul A. Dutchak
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Université Laval, Quebec City, QC G1J 2G3, Canada
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Du S, Zeng S, Song L, Ma H, Chen R, Luo J, Wang X, Ma T, Xu X, Sun H, Yi P, Guo J, Huang Y, Liu M, Wang T, Liao WP, Zhang L, Liu JY, Tang B. Functional characterization of novel NPRL3 mutations identified in three families with focal epilepsy. SCIENCE CHINA. LIFE SCIENCES 2023; 66:2152-2166. [PMID: 37071290 DOI: 10.1007/s11427-022-2313-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 03/01/2023] [Indexed: 04/19/2023]
Abstract
Focal epilepsy accounts for 60% of all forms of epilepsy, but the pathogenic mechanism is not well understood. In this study, three novel mutations in NPRL3 (nitrogen permease regulator-like 3), c.937_945del, c.1514dupC and 6,706-bp genomic DNA (gDNA) deletion, were identified in three families with focal epilepsy by linkage analysis, whole exome sequencing (WES) and Sanger sequencing. NPRL3 protein is a component of the GATOR1 complex, a major inhibitor of mTOR signaling. These mutations led to truncation of the NPRL3 protein and hampered the binding between NPRL3 and DEPDC5, which is another component of the GATOR1 complex. Consequently, the mutant proteins enhanced mTOR signaling in cultured cells, possibly due to impaired inhibition of mTORC1 by GATOR1. Knockdown of nprl3 in Drosophila resulted in epilepsy-like behavior and abnormal synaptic development. Taken together, these findings expand the genotypic spectrum of NPRL3-associated focal epilepsy and provide further insight into how NPRL3 mutations lead to epilepsy.
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Affiliation(s)
- Shiyue Du
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China
| | - Sheng Zeng
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, China
- Department of Geriatrics, The Second Xiangya Hospital, Central South University, Changsha, 410011, China
| | - Li Song
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China
| | - Hongying Ma
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China
| | - Rui Chen
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China
| | - Junyu Luo
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China
| | - Xu Wang
- National Reference Laboratory of Veterinary Drug Residues and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, 430070, China
| | - Tingbin Ma
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Xuan Xu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Hao Sun
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Ping Yi
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China
| | - Jifeng Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Yaling Huang
- Department of Neurology, Union Hospital of HUST, Wuhan, 430022, China
| | - Mugen Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China
| | - Tao Wang
- Department of Neurology, Union Hospital of HUST, Wuhan, 430022, China
| | - Wei-Ping Liao
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou Medical University, Guangzhou, 510260, China
| | - Luoying Zhang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China.
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, 430022, China.
| | - Jing Yu Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China.
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, China.
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, 410008, China.
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Lambooy S, Heida A, Joschko C, Nakladal D, van Buiten A, Kloosterhuis N, Huijkman N, Gerding A, van de Sluis B, Henning R, Deelman L. Selective Hepatic Cbs Knockout Aggravates Liver Damage, Endothelial Dysfunction and ROS Stress in Mice Fed a Western Diet. Int J Mol Sci 2023; 24:ijms24087019. [PMID: 37108182 PMCID: PMC10138434 DOI: 10.3390/ijms24087019] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 04/07/2023] [Accepted: 04/08/2023] [Indexed: 04/29/2023] Open
Abstract
Cystathionine-β-synthase (CBS) is highly expressed in the liver, and deficiencies in Cbs lead to hyperhomocysteinemia (HHCy) and disturbed production of antioxidants such as hydrogen sulfide. We therefore hypothesized that liver-specific Cbs deficient (LiCKO) mice would be particularly susceptible to the development of non-alcoholic fatty liver disease (NAFLD). NAFLD was induced by a high-fat high-cholesterol (HFC) diet; LiCKO and controls were split into eight groups based on genotype (con, LiCKO), diet (normal diet, HFC), and diet duration (12 weeks, 20 weeks). LiCKO mice displayed intermediate to severe HHCy. Plasma H2O2 was increased by HFC, and further aggravated in LiCKO. LiCKO mice fed an HFC diet had heavier livers, increased lipid peroxidation, elevated ALAT, aggravated hepatic steatosis, and inflammation. LiCKO mice showed decreased L-carnitine in the liver, but this did not result in impaired fatty acid oxidation. Moreover, HFC-fed LiCKO mice demonstrated vascular and renal endothelial dysfunction. Liver and endothelial damage correlated significantly with systemic ROS status. In conclusion, this study demonstrates an important role for CBS in the liver in the development of NAFLD, which is most probably mediated through impaired defense against oxidative stress.
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Affiliation(s)
- Sebastiaan Lambooy
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, The Netherlands
| | - Andries Heida
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, The Netherlands
| | - Christian Joschko
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, The Netherlands
| | - Dalibor Nakladal
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, The Netherlands
| | - Azuwerus van Buiten
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, The Netherlands
| | - Niels Kloosterhuis
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, The Netherlands
| | - Nicolette Huijkman
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, The Netherlands
| | - Albert Gerding
- Department of Laboratory Medicine, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, The Netherlands
| | - Bart van de Sluis
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, The Netherlands
| | - Robert Henning
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, The Netherlands
| | - Leo Deelman
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, The Netherlands
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Zeng X, Wang YP, Man CH. Metabolism in Hematopoiesis and Its Malignancy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1442:45-64. [PMID: 38228958 DOI: 10.1007/978-981-99-7471-9_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Hematopoietic stem cells (HSCs) are multipotent stem cells that can self-renew and generate all blood cells of different lineages. The system is under tight control in order to maintain a precise equilibrium of the HSC pool and the effective production of mature blood cells to support various biological activities. Cell metabolism can regulate different molecular activities, such as epigenetic modification and cell cycle regulation, and subsequently affects the function and maintenance of HSC. Upon malignant transformation, oncogenic drivers in malignant hematopoietic cells can remodel the metabolic pathways for supporting the oncogenic growth. The dysregulation of metabolism results in oncogene addiction, implying the development of malignancy-specific metabolism-targeted therapy. In this chapter, we will discuss the significance of different metabolic pathways in hematopoiesis, specifically, the distinctive metabolic dependency in hematopoietic malignancies and potential metabolic therapy.
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Affiliation(s)
- Xiaoyuan Zeng
- Division of Haematology, Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Yi-Ping Wang
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Cheuk-Him Man
- Division of Haematology, Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
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Yan Y, Chen C, Li Z, Zhang J, Park N, Qu CK. Extracellular arginine is required but the arginine transporter CAT3 (Slc7a3) is dispensable for mouse normal and malignant hematopoiesis. Sci Rep 2022; 12:21832. [PMID: 36528691 PMCID: PMC9759514 DOI: 10.1038/s41598-022-24554-2] [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: 06/06/2022] [Accepted: 11/16/2022] [Indexed: 12/23/2022] Open
Abstract
Amino acid-mediated metabolism is one of the key catabolic and anabolic processes involved in diverse cellular functions. However, the role of the semi-essential amino acid arginine in normal and malignant hematopoietic cell development is poorly understood. Here we report that a continuous supply of exogenous arginine is required for the maintenance/function of normal hematopoietic stem cells (HSCs). Surprisingly, knockout of Slc7a3 (CAT3), a major L-arginine transporter, does not affect HSCs in steady-state or under stress. Although Slc7a3 is highly expressed in naïve and activated CD8 T cells, neither T cell development nor activation/proliferation is impacted by Slc7a3 depletion. Furthermore, the Slc7a3 deletion does not attenuate leukemia development driven by Pten loss or the oncogenic Ptpn11E76K mutation. Arginine uptake assays reveal that L-arginine uptake is not disrupted in Slc7a3 knockout cells. These data suggest that extracellular arginine is critically important for HSCs, but CAT3 is dispensable for normal hematopoiesis and leukemogenesis.
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Affiliation(s)
- Yuhan Yan
- grid.189967.80000 0001 0941 6502Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Winship Cancer Institute, Children’s Healthcare of Atlanta, Emory University School of Medicine, 1760 Haygood Drive NE, HSRB E302, Atlanta, GA 30322 USA
| | - Chao Chen
- grid.189967.80000 0001 0941 6502Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Winship Cancer Institute, Children’s Healthcare of Atlanta, Emory University School of Medicine, 1760 Haygood Drive NE, HSRB E302, Atlanta, GA 30322 USA
| | - Zhiguo Li
- grid.189967.80000 0001 0941 6502Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Winship Cancer Institute, Children’s Healthcare of Atlanta, Emory University School of Medicine, 1760 Haygood Drive NE, HSRB E302, Atlanta, GA 30322 USA
| | - Jing Zhang
- grid.189967.80000 0001 0941 6502Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Winship Cancer Institute, Children’s Healthcare of Atlanta, Emory University School of Medicine, 1760 Haygood Drive NE, HSRB E302, Atlanta, GA 30322 USA
| | - Narin Park
- grid.189967.80000 0001 0941 6502Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Winship Cancer Institute, Children’s Healthcare of Atlanta, Emory University School of Medicine, 1760 Haygood Drive NE, HSRB E302, Atlanta, GA 30322 USA
| | - Cheng-Kui Qu
- grid.189967.80000 0001 0941 6502Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Winship Cancer Institute, Children’s Healthcare of Atlanta, Emory University School of Medicine, 1760 Haygood Drive NE, HSRB E302, Atlanta, GA 30322 USA
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9
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Yin N, Jin G, Ma Y, Zhao H, Zhang G, Li MO, Peng M. SZT2 maintains hematopoietic stem cell homeostasis via nutrient-mediated mTORC1 regulation. J Clin Invest 2022; 132:146272. [PMID: 36250465 PMCID: PMC9566891 DOI: 10.1172/jci146272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 08/19/2022] [Indexed: 11/17/2022] Open
Abstract
The mTORC1 pathway coordinates nutrient and growth factor signals to maintain organismal homeostasis. Whether nutrient signaling to mTORC1 regulates stem cell function remains unknown. Here, we show that SZT2 — a protein required for mTORC1 downregulation upon nutrient deprivation — is critical for hematopoietic stem cell (HSC) homeostasis. Ablation of SZT2 in HSCs decreased the reserve and impaired the repopulating capacity of HSCs. Furthermore, ablation of both SZT2 and TSC1 — 2 repressors of mTORC1 on the nutrient and growth factor arms, respectively — led to rapid HSC depletion, pancytopenia, and premature death of the mice. Mechanistically, loss of either SZT2 or TSC1 in HSCs led to only mild elevation of mTORC1 activity and reactive oxygen species (ROS) production. Loss of both SZT2 and TSC1, on the other hand, simultaneously produced a dramatic synergistic effect, with an approximately 10-fold increase of mTORC1 activity and approximately 100-fold increase of ROS production, which rapidly depleted HSCs. These data demonstrate a critical role of nutrient mTORC1 signaling in HSC homeostasis and uncover a strong synergistic effect between nutrient- and growth factor–mediated mTORC1 regulation in stem cells.
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Affiliation(s)
- Na Yin
- Department of Basic Medical Sciences, School of Medicine, and
- Institute for Immunology, Tsinghua University, Beijing, China
| | - Gang Jin
- Department of Basic Medical Sciences, School of Medicine, and
- Institute for Immunology, Tsinghua University, Beijing, China
| | - Yuying Ma
- Department of Basic Medical Sciences, School of Medicine, and
- Institute for Immunology, Tsinghua University, Beijing, China
| | - Hanfei Zhao
- Department of Basic Medical Sciences, School of Medicine, and
- Institute for Immunology, Tsinghua University, Beijing, China
| | - Guangyue Zhang
- Department of Basic Medical Sciences, School of Medicine, and
- Institute for Immunology, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Ming O. Li
- Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York, USA
- Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, New York, USA
| | - Min Peng
- Department of Basic Medical Sciences, School of Medicine, and
- Institute for Immunology, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
- Beijing Key Laboratory for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
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10
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Specchio N, Pietrafusa N, Perucca E, Cross JH. New paradigms for the treatment of pediatric monogenic epilepsies: Progressing toward precision medicine. Epilepsy Behav 2022; 131:107961. [PMID: 33867301 DOI: 10.1016/j.yebeh.2021.107961] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/25/2022]
Abstract
Despite the availability of 28 antiseizure medications (ASMs), one-third of people with epilepsy fail to achieve sustained freedom from seizures. Clinical outcome is even poorer for children with developmental and epileptic encephalopathies (DEEs), many of which are due to single-gene mutations. Discovery of causative genes, however, has paved the way to understanding the molecular mechanism underlying these epilepsies, and to the rational application, or development, of precision treatments aimed at correcting the specific functional defects or their consequences. This article provides an overview of current progress toward precision medicine (PM) in the management of monogenic pediatric epilepsies, by focusing on four different scenarios, namely (a) rational selection of ASMs targeting specifically the underlying pathogenetic mechanisms; (b) development of targeted therapies based on novel molecules; (c) use of dietary treatments or food constituents aimed at correcting specific metabolic defects; and (d) repurposing of medications originally approved for other indications. This article is part of the Special Issue "Severe Infantile Epilepsies".
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Affiliation(s)
- Nicola Specchio
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy.
| | - Nicola Pietrafusa
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy
| | - Emilio Perucca
- Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy
| | - J Helen Cross
- UCL NIHR BRC Great Ormond Street Institute of Child Health and Great Ormond Street Hospital for Children, London, UK
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11
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Dentel B, Angeles-Perez L, Ren C, Jakkamsetti V, Holley AJ, Caballero D, Oh E, Gibson J, Pascual JM, Huber KM, Tu BP, Tsai PT. Increased glycine contributes to synaptic dysfunction and early mortality in Nprl2 seizure model. iScience 2022; 25:104334. [PMID: 35602938 PMCID: PMC9118754 DOI: 10.1016/j.isci.2022.104334] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 09/16/2021] [Accepted: 04/26/2022] [Indexed: 10/25/2022] Open
Abstract
Targeted therapies for epilepsies associated with the mTORC1 signaling negative regulator GATOR1 are lacking. NPRL2 is a subunit of the GATOR1 complex and mutations in GATOR1 subunits, including NPRL2, are associated with epilepsy. To delineate the mechanisms underlying NPRL2-related epilepsies, we created a mouse (Mus musculus) model with neocortical loss of Nprl2. Mutant mice have increased mTORC1 signaling and exhibit spontaneous seizures. They also display abnormal synaptic function characterized by increased evoked and spontaneous EPSC and decreased evoked and spontaneous IPSC frequencies, respectively. Proteomic and metabolomics studies of Nprl2 mutants revealed alterations in known epilepsy-implicated proteins and metabolic pathways, including increases in the neurotransmitter, glycine. Furthermore, glycine actions on the NMDA receptor contribute to the electrophysiological and survival phenotypes of these mice. Taken together, in this neuronal Nprl2 model, we delineate underlying molecular, metabolic, and electrophysiological mechanisms contributing to mTORC1-related epilepsy, providing potential therapeutic targets for epilepsy.
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Affiliation(s)
- Brianne Dentel
- Department of Neurology, UT Southwestern Medical Center, Dallas, TX 75235, USA
| | | | - Chongyu Ren
- Department of Neurology, UT Southwestern Medical Center, Dallas, TX 75235, USA
| | - Vikram Jakkamsetti
- Department of Neurology, UT Southwestern Medical Center, Dallas, TX 75235, USA
| | - Andrew J. Holley
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75235, USA
| | - Daniel Caballero
- Department of Neurology, UT Southwestern Medical Center, Dallas, TX 75235, USA
| | - Emily Oh
- Department of Neurology, UT Southwestern Medical Center, Dallas, TX 75235, USA
| | - Jay Gibson
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75235, USA
| | - Juan M. Pascual
- Department of Neurology, UT Southwestern Medical Center, Dallas, TX 75235, USA
| | - Kimberly M. Huber
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75235, USA
| | - Benjamin P. Tu
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75235, USA
| | - Peter T. Tsai
- Department of Neurology, UT Southwestern Medical Center, Dallas, TX 75235, USA
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75235, USA
- Departments of Pediatrics and Psychiatry, UT Southwestern Medical Center, Dallas, TX 75235, USA
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12
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Ashrafizadeh M, Paskeh MDA, Mirzaei S, Gholami MH, Zarrabi A, Hashemi F, Hushmandi K, Hashemi M, Nabavi N, Crea F, Ren J, Klionsky DJ, Kumar AP, Wang Y. Targeting autophagy in prostate cancer: preclinical and clinical evidence for therapeutic response. J Exp Clin Cancer Res 2022; 41:105. [PMID: 35317831 PMCID: PMC8939209 DOI: 10.1186/s13046-022-02293-6] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 02/16/2022] [Indexed: 02/08/2023] Open
Abstract
Prostate cancer is a leading cause of death worldwide and new estimates revealed prostate cancer as the leading cause of death in men in 2021. Therefore, new strategies are pertinent in the treatment of this malignant disease. Macroautophagy/autophagy is a “self-degradation” mechanism capable of facilitating the turnover of long-lived and toxic macromolecules and organelles. Recently, attention has been drawn towards the role of autophagy in cancer and how its modulation provides effective cancer therapy. In the present review, we provide a mechanistic discussion of autophagy in prostate cancer. Autophagy can promote/inhibit proliferation and survival of prostate cancer cells. Besides, metastasis of prostate cancer cells is affected (via induction and inhibition) by autophagy. Autophagy can affect the response of prostate cancer cells to therapy such as chemotherapy and radiotherapy, given the close association between autophagy and apoptosis. Increasing evidence has demonstrated that upstream mediators such as AMPK, non-coding RNAs, KLF5, MTOR and others regulate autophagy in prostate cancer. Anti-tumor compounds, for instance phytochemicals, dually inhibit or induce autophagy in prostate cancer therapy. For improving prostate cancer therapy, nanotherapeutics such as chitosan nanoparticles have been developed. With respect to the context-dependent role of autophagy in prostate cancer, genetic tools such as siRNA and CRISPR-Cas9 can be utilized for targeting autophagic genes. Finally, these findings can be translated into preclinical and clinical studies to improve survival and prognosis of prostate cancer patients. • Prostate cancer is among the leading causes of death in men where targeting autophagy is of importance in treatment; • Autophagy governs proliferation and metastasis capacity of prostate cancer cells; • Autophagy modulation is of interest in improving the therapeutic response of prostate cancer cells; • Molecular pathways, especially involving non-coding RNAs, regulate autophagy in prostate cancer; • Autophagy possesses both diagnostic and prognostic roles in prostate cancer, with promises for clinical application.
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Affiliation(s)
- Milad Ashrafizadeh
- Faculty of Engineering and Natural Sciences, Sabanci University, Orta Mahalle, Üniversite Caddesi No. 27, Orhanlı, Tuzla, 34956, Istanbul, Turkey.
| | - Mahshid Deldar Abad Paskeh
- Department of Genetics, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.,Farhikhtegan Medical Convergence sciences Research Center, Farhikhtegan Hospital Tehran Medical sciences, Islamic Azad University, Tehran, Iran
| | - Sepideh Mirzaei
- Department of Biology, Faculty of Science, Islamic Azad University, Science and Research Branch, Tehran, Iran
| | | | - Ali Zarrabi
- Department of Biomedical Engineering, Faculty of Engineering and Natural Sciences, Istinye University, 34396, Istanbul, Turkey
| | - Farid Hashemi
- Department of Comparative Biosciences, Faculty of Veterinary Medicine, University of Tehran, Tehran, 1417466191, Iran
| | - Kiavash Hushmandi
- Department of Food Hygiene and Quality Control, Division of Epidemiology & Zoonoses, Faculty of Veterinary Medicine University of Tehran, Tehran, Iran
| | - Mehrdad Hashemi
- Department of Genetics, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.,Farhikhtegan Medical Convergence sciences Research Center, Farhikhtegan Hospital Tehran Medical sciences, Islamic Azad University, Tehran, Iran
| | - Noushin Nabavi
- Department of Urological Sciences and Vancouver Prostate Centre, University of British Columbia, V6H3Z6, Vancouver, BC, Canada
| | - Francesco Crea
- Cancer Research Group-School of Life Health and Chemical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK
| | - Jun Ren
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA.,Shanghai Institute of Cardiovascular Diseases, Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Daniel J Klionsky
- Life Sciences Institute & Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Alan Prem Kumar
- Cancer Science Institute of Singapore and Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117599, Singapore. .,NUS Centre for Cancer Research (N2CR), Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
| | - Yuzhuo Wang
- Department of Urological Sciences and Vancouver Prostate Centre, University of British Columbia, V6H3Z6, Vancouver, BC, Canada.
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13
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Hui JB, Silva JCH, Pelaez MC, Sévigny M, Venkatasubramani JP, Plumereau Q, Chahine M, Proulx CD, Sephton CF, Dutchak PA. NPRL2 Inhibition of mTORC1 Controls Sodium Channel Expression and Brain Amino Acid Homeostasis. eNeuro 2022; 9:ENEURO.0317-21.2022. [PMID: 35165201 PMCID: PMC8896560 DOI: 10.1523/eneuro.0317-21.2022] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 12/19/2022] Open
Abstract
Genetic mutations in nitrogen permease regulator-like 2 (NPRL2) are associated with a wide spectrum of familial focal epilepsies, autism, and sudden unexpected death of epileptics (SUDEP), but the mechanisms by which NPRL2 contributes to these effects are not well known. NPRL2 is a requisite subunit of the GAP activity toward Rags 1 (GATOR1) complex, which functions as a negative regulator of mammalian target of rapamycin complex 1 (mTORC1) kinase when intracellular amino acids are low. Here, we show that loss of NPRL2 expression in mouse excitatory glutamatergic neurons causes seizures before death, consistent with SUDEP in humans with epilepsy. Additionally, the absence of NPRL2 expression increases mTORC1-dependent signal transduction and significantly alters amino acid homeostasis in the brain. Loss of NPRL2 reduces dendritic branching and increases the strength of electrically stimulated action potentials (APs) in neurons. The increased AP strength is consistent with elevated expression of epilepsy-linked, voltage-gated sodium channels in the NPRL2-deficient brain. Targeted deletion of NPRL2 in primary neurons increases the expression of sodium channel Scn1A, whereas treatment with the pharmacological mTORC1 inhibitor called rapamycin prevents Scn1A upregulation. These studies demonstrate a novel role of NPRL2 and mTORC1 signaling in the regulation of sodium channels, which can contribute to seizures and early lethality.
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Affiliation(s)
- Jeremy B Hui
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Université Laval, Quebec City, Quebec G1J 2G3, Canada
| | - Jose Cesar Hernandez Silva
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Université Laval, Quebec City, Quebec G1J 2G3, Canada
| | - Mari Carmen Pelaez
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Université Laval, Quebec City, Quebec G1J 2G3, Canada
| | - Myriam Sévigny
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Université Laval, Quebec City, Quebec G1J 2G3, Canada
| | - Janani Priya Venkatasubramani
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Université Laval, Quebec City, Quebec G1J 2G3, Canada
| | - Quentin Plumereau
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Université Laval, Quebec City, Quebec G1J 2G3, Canada
| | - Mohamed Chahine
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Université Laval, Quebec City, Quebec G1J 2G3, Canada
| | - Christophe D Proulx
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Université Laval, Quebec City, Quebec G1J 2G3, Canada
| | - Chantelle F Sephton
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Université Laval, Quebec City, Quebec G1J 2G3, Canada
| | - Paul A Dutchak
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Université Laval, Quebec City, Quebec G1J 2G3, Canada
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14
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Roy MK, La Carpia F, Cendali F, Fernando S, Moriconi C, Wojczyk BS, Wang L, Nemkov T, Hod EA, D’Alessandro A. Irradiation Causes Alterations of Polyamine, Purine, and Sulfur Metabolism in Red Blood Cells and Multiple Organs. J Proteome Res 2022; 21:519-534. [PMID: 35043621 PMCID: PMC8855667 DOI: 10.1021/acs.jproteome.1c00912] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Investigating the metabolic effects of radiation is critical to understand the impact of radiotherapy, space travel, and exposure to environmental radiation. In patients undergoing hemopoietic stem cell transplantation, iron overload is a common risk factor for poor outcomes. However, no studies have interrogated the multiorgan effects of these treatments concurrently. Herein, we use a model that recapitulates transfusional iron overload, a condition often observed in chronically transfused patients. We applied an omics approach to investigate the impact of both the iron load and irradiation on the host metabolome. The results revealed dose-dependent effects of irradiation in the red blood cells, plasma, spleen, and liver energy and redox metabolism. Increases in polyamines and purine salvage metabolites were observed in organs with high oxygen consumption including the heart, kidneys, and brain. Irradiation also impacted the metabolism of the duodenum, colon, and stool, suggesting a potential effect on the microbiome. Iron infusion affected the response to radiation in the organs and blood, especially in erythrocyte polyamines and spleen antioxidant metabolism, and affected glucose, methionine, and glutathione systems and tryptophan metabolism in the liver, stool, and the brain. Together, the results suggest that radiation impacts metabolism on a multiorgan level with a significant interaction of the host iron status.
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Affiliation(s)
- Micaela Kalani Roy
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver – Anschutz Medical Campus, Aurora, CO, USA 80045
| | | | - Francesca Cendali
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver – Anschutz Medical Campus, Aurora, CO, USA 80045
| | | | - Chiara Moriconi
- Columbia University Irving Medical Center, New York, NY, USA 10032
| | | | - Lin Wang
- Columbia University Irving Medical Center, New York, NY, USA 10032
| | - Travis Nemkov
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver – Anschutz Medical Campus, Aurora, CO, USA 80045
| | - Eldad A Hod
- Columbia University Irving Medical Center, New York, NY, USA 10032
| | - Angelo D’Alessandro
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver – Anschutz Medical Campus, Aurora, CO, USA 80045,Corresponding authors: Angelo D’Alessandro, PhD, Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, 12801 East 17th Ave., Aurora, CO 80045, Phone # 303-724-0096,
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15
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Ishida S, Zhao D, Sawada Y, Hiraoka Y, Mashimo T, Tanaka K. Dorsal telencephalon-specific Nprl2- and Nprl3-knockout mice: novel mouse models for GATORopathy. Hum Mol Genet 2021; 31:1519-1530. [PMID: 34965576 PMCID: PMC9071434 DOI: 10.1093/hmg/ddab337] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 09/28/2021] [Accepted: 11/12/2021] [Indexed: 11/30/2022] Open
Abstract
The most frequent genetic cause of focal epilepsies is variations in the GAP activity toward RAGs 1 complex genes DEP domain containing 5 (DEPDC5), nitrogen permease regulator 2-like protein (NPRL2) and nitrogen permease regulator 3-like protein (NPRL3). Because these variations are frequent and associated with a broad spectrum of focal epilepsies, a unique pathology categorized as GATORopathy can be conceptualized. Animal models recapitulating the clinical features of patients are essential to decipher GATORopathy. Although several genetically modified animal models recapitulate DEPDC5-related epilepsy, no models have been reported for NPRL2- or NPRL3-related epilepsies. Here, we conditionally deleted Nprl2 and Nprl3 from the dorsal telencephalon in mice [Emx1cre/+; Nprl2f/f (Nprl2-cKO) and Emx1cre/+; Nprl3f/f (Nprl3-cKO)] and compared their phenotypes with Nprl2+/−, Nprl3+/− and Emx1cre/+; Depdc5f/f (Depdc5-cKO) mice. Nprl2-cKO and Nprl3-cKO mice recapitulated the major abnormal features of patients—spontaneous seizures, and dysmorphic enlarged neuronal cells with increased mechanistic target of rapamycin complex 1 signaling—similar to Depdc5-cKO mice. Chronic postnatal rapamycin administration dramatically prolonged the survival period and inhibited seizure occurrence but not enlarged neuronal cells in Nprl2-cKO and Nprl3-cKO mice. However, the benefit of rapamycin after withdrawal was less durable in Nprl2- and Nprl3-cKO mice compared with Depdc5-cKO mice. Further studies using these conditional knockout mice will be useful for understanding GATORopathy and for the identification of novel therapeutic targets.
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Affiliation(s)
- Saeko Ishida
- Laboratory of Molecular Neuroscience, Medical Research Institute (MRI), Tokyo Medical and Dental University (TMDU), Tokyo, 113-8510, Japan
- Division of Animal Genetics, Laboratory Animal Research Center, The Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan
| | - Di Zhao
- Laboratory of Molecular Neuroscience, Medical Research Institute (MRI), Tokyo Medical and Dental University (TMDU), Tokyo, 113-8510, Japan
- Division of Animal Genetics, Laboratory Animal Research Center, The Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan
| | - Yuta Sawada
- Laboratory of Molecular Neuroscience, Medical Research Institute (MRI), Tokyo Medical and Dental University (TMDU), Tokyo, 113-8510, Japan
| | - Yuichi Hiraoka
- Laboratory of Molecular Neuroscience, Medical Research Institute (MRI), Tokyo Medical and Dental University (TMDU), Tokyo, 113-8510, Japan
- Laboratory of Genome Editing for Biomedical Research, MRI, TMDU, Tokyo, 101-0062, Japan
| | - Tomoji Mashimo
- Division of Animal Genetics, Laboratory Animal Research Center, The Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan
| | - Kohichi Tanaka
- Laboratory of Molecular Neuroscience, Medical Research Institute (MRI), Tokyo Medical and Dental University (TMDU), Tokyo, 113-8510, Japan
- Center for Brain Integration Research (CBIR), TMDU, Tokyo, 113-8510, Japan
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16
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Loissell-Baltazar YA, Dokudovskaya S. SEA and GATOR 10 Years Later. Cells 2021; 10:cells10102689. [PMID: 34685669 PMCID: PMC8534245 DOI: 10.3390/cells10102689] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/30/2021] [Accepted: 10/03/2021] [Indexed: 12/17/2022] Open
Abstract
The SEA complex was described for the first time in yeast Saccharomyces cerevisiae ten years ago, and its human homologue GATOR complex two years later. During the past decade, many advances on the SEA/GATOR biology in different organisms have been made that allowed its role as an essential upstream regulator of the mTORC1 pathway to be defined. In this review, we describe these advances in relation to the identification of multiple functions of the SEA/GATOR complex in nutrient response and beyond and highlight the consequence of GATOR mutations in cancer and neurodegenerative diseases.
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17
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Sévigny M, Bourdeau Julien I, Venkatasubramani JP, Hui JB, Dutchak PA, Sephton CF. FUS contributes to mTOR-dependent inhibition of translation. J Biol Chem 2020; 295:18459-18473. [PMID: 33082139 PMCID: PMC7939483 DOI: 10.1074/jbc.ra120.013801] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 10/15/2020] [Indexed: 12/13/2022] Open
Abstract
The amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD)-linked RNA-binding protein called FUS (fused in sarcoma) has been implicated in several aspects of RNA regulation, including mRNA translation. The mechanism by which FUS affects the translation of polyribosomes has not been established. Here we show that FUS can associate with stalled polyribosomes and that this association is sensitive to mTOR (mammalian target of rapamycin) kinase activity. Specifically, we show that FUS association with polyribosomes is increased by Torin1 treatment or when cells are cultured in nutrient-deficient media, but not when cells are treated with rapamycin, the allosteric inhibitor of mTORC1. Moreover, we report that FUS is necessary for efficient stalling of translation because deficient cells are refractory to the inhibition of mTOR-dependent signaling by Torin1. We also show that ALS-linked FUS mutants R521G and P525L associate abundantly with polyribosomes and decrease global protein synthesis. Importantly, the inhibitory effect on translation by FUS is impaired by mutations that reduce its RNA-binding affinity. These findings demonstrate that FUS is an important RNA-binding protein that mediates translational repression through mTOR-dependent signaling and that ALS-linked FUS mutants can cause a toxic gain of function in the cytoplasm by repressing the translation of mRNA at polyribosomes.
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Affiliation(s)
- Myriam Sévigny
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Isabelle Bourdeau Julien
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Janani Priya Venkatasubramani
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Jeremy B Hui
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Paul A Dutchak
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Chantelle F Sephton
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada.
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18
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Impact of predictive, preventive and precision medicine strategies in epilepsy. Nat Rev Neurol 2020; 16:674-688. [PMID: 33077944 DOI: 10.1038/s41582-020-0409-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2020] [Indexed: 12/15/2022]
Abstract
Over the last decade, advances in genetics, neuroimaging and EEG have enabled the aetiology of epilepsy to be identified earlier in the disease course than ever before. At the same time, progress in the study of experimental models of epilepsy has provided a better understanding of the mechanisms underlying the condition and has enabled the identification of therapies that target specific aetiologies. We are now witnessing the impact of these advances in our daily clinical practice. Thus, now is the time for a paradigm shift in epilepsy treatment from a reactive attitude, treating patients after the onset of epilepsy and the initiation of seizures, to a proactive attitude that is more broadly integrated into a 'P4 medicine' approach. This P4 approach, which is personalized, predictive, preventive and participatory, puts patients at the centre of their own care and, ultimately, aims to prevent the onset of epilepsy. This aim will be achieved by adapting epilepsy treatments not only to a given syndrome but also to a given patient and moving from the usual anti-seizure treatments to personalized treatments designed to target specific aetiologies. In this Review, we present the current state of this ongoing revolution, emphasizing the impact on clinical practice.
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19
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Luo S, Shao L, Chen Z, Hu D, Jiang L, Tang W. NPRL2 promotes docetaxel chemoresistance in castration resistant prostate cancer cells by regulating autophagy through the mTOR pathway. Exp Cell Res 2020; 390:111981. [PMID: 32234375 DOI: 10.1016/j.yexcr.2020.111981] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 03/16/2020] [Accepted: 03/27/2020] [Indexed: 12/14/2022]
Abstract
Docetaxel-based chemotherapy is recommended for metastatic castration-resistant prostate cancer (mCRPC). However, chemoresistance is inevitable and eventually progresses after several rounds of chemotherapy. Therefore, exploration of new therapeutic targets and molecular mechanisms that contribute to chemoresistance remains necessary. Our previous study accidentally demonstrated that expression of nitrogen permease regulator-like 2 (NPRL2), which is defined as a tumor suppressor, is upregulated in prostate cancer (PCa) and linked to poor prognosis, particularly in CRPC. The aim of this study was to investigate the role of NPRL2 in the chemoresistant CRPC cells. We found that NPRL2 was significantly overexpressed in docetaxel-resistant CRPC cells, while autophagy was enhanced and mTOR signaling was inhibited. Inhibiting NPRL2 increased the sensitivity to docetaxel in docetaxel-resistant CRPC cells, enhanced apoptosis and inhibited autophagy, and the opposite trends were observed when the mTOR inhibitor torin 1 was added to NPRL2-silenced cells. We further found that NPRL2 silenced docetaxel-resistant CRPC cells were sensitive to docetaxel in vivo. Briefly, our research reveals that overexpression of NPRL2 promotes chemoresistance by regulating autophagy via mTOR signaling and inhibits apoptosis in CRPC cells.
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Affiliation(s)
- Shengjun Luo
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
| | - Lan Shao
- Department of Rehabilitation, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
| | - Zhixiong Chen
- Department of Gastrointestinal Surgery, Chongqing University Cancer Hospital, Chongqing, China.
| | - Daixing Hu
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
| | - Li Jiang
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
| | - Wei Tang
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
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20
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Bertuzzi M, Tang D, Calligaris R, Vlachouli C, Finaurini S, Sanges R, Goldwurm S, Catalan M, Antonutti L, Manganotti P, Pizzolato G, Pezzoli G, Persichetti F, Carninci P, Gustincich S. A human minisatellite hosts an alternative transcription start site for NPRL3 driving its expression in a repeat number-dependent manner. Hum Mutat 2020; 41:807-824. [PMID: 31898848 DOI: 10.1002/humu.23974] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 11/16/2019] [Accepted: 12/24/2019] [Indexed: 12/21/2022]
Abstract
Minisatellites, also called variable number of tandem repeats (VNTRs), are a class of repetitive elements that may affect gene expression at multiple levels and have been correlated to disease. Their identification and role as expression quantitative trait loci (eQTL) have been limited by their absence in comparative genomic hybridization and single nucleotide polymorphisms arrays. By taking advantage of cap analysis of gene expression (CAGE), we describe a new example of a minisatellite hosting a transcription start site (TSS) which expression is dependent on the repeat number. It is located in the third intron of the gene nitrogen permease regulator like protein 3 (NPRL3). NPRL3 is a component of the GAP activity toward rags 1 protein complex that inhibits mammalian target of rapamycin complex 1 (mTORC1) activity and it is found mutated in familial focal cortical dysplasia and familial focal epilepsy. CAGE tags represent an alternative TSS identifying TAGNPRL3 messenger RNAs (mRNAs). TAGNPRL3 is expressed in red blood cells both at mRNA and protein levels, it interacts with its protein partner NPRL2 and its overexpression inhibits cell proliferation. This study provides an example of a minisatellite that is both a TSS and an eQTL as well as identifies a new VNTR that may modify mTORC1 activity.
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Affiliation(s)
| | - Dave Tang
- Division of Genomic Technologies, RIKEN Center for Life Science Technologies, Yokohama, Japan
| | - Raffaella Calligaris
- Area of Neuroscience, SISSA, Trieste, Italy.,Department of Medical Sciences, Neurology Unit, University of Trieste, Trieste, Italy
| | | | - Sara Finaurini
- Area of Neuroscience, SISSA, Trieste, Italy.,Department of Health Sciences, Università del Piemonte Orientale and IRCAD, Novara, Italy
| | - Remo Sanges
- Area of Neuroscience, SISSA, Trieste, Italy.,Central RNA Laboratory, Istituto Italiano di Tecnologia, Genova, Italy
| | | | - Mauro Catalan
- Department of Medical Sciences, Neurology Unit, University of Trieste, Trieste, Italy
| | - Lucia Antonutti
- Department of Medical Sciences, Neurology Unit, University of Trieste, Trieste, Italy
| | - Paolo Manganotti
- Department of Medical Sciences, Neurology Unit, University of Trieste, Trieste, Italy
| | - Gilberto Pizzolato
- Department of Medical Sciences, Neurology Unit, University of Trieste, Trieste, Italy
| | - Gianni Pezzoli
- Parkinson Institute, ASST G. Pini-CTO, ex ICP, Milan, Italy
| | - Francesca Persichetti
- Department of Health Sciences, Università del Piemonte Orientale and IRCAD, Novara, Italy
| | - Piero Carninci
- Division of Genomic Technologies, RIKEN Center for Life Science Technologies, Yokohama, Japan.,Laboratory for Transcriptome Technology, RIKEN Center for Integrative Medical Sciences (IMS), Yokohama, Japan
| | - Stefano Gustincich
- Area of Neuroscience, SISSA, Trieste, Italy.,Central RNA Laboratory, Istituto Italiano di Tecnologia, Genova, Italy
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21
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Dutchak PA, Estill-Terpack SJ, Plec AA, Zhao X, Yang C, Chen J, Ko B, Deberardinis RJ, Yu Y, Tu BP. Loss of a Negative Regulator of mTORC1 Induces Aerobic Glycolysis and Altered Fiber Composition in Skeletal Muscle. Cell Rep 2019; 23:1907-1914. [PMID: 29768191 PMCID: PMC6038807 DOI: 10.1016/j.celrep.2018.04.058] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 12/28/2017] [Accepted: 04/13/2018] [Indexed: 01/11/2023] Open
Abstract
The conserved GATOR1 complex consisting of NPRL2-NPRL3-DEPDC5 inhibits mammalian target of rapamycin complex 1 (mTORC1) in response to amino acid insufficiency. Here, we show that loss of NPRL2 and GATOR1 function in skeletal muscle causes constitutive activation of mTORC1 signaling in the fed and fasted states. Muscle fibers of NPRL2 knockout animals are significantly larger and show altered fiber-type composition, with more fast-twitch glycolytic and fewer slow-twitch oxidative fibers. NPRL2 muscle knockout mice also have altered running behavior and enhanced glucose tolerance. Furthermore, loss of NPRL2 induces aerobic glycolysis and suppresses glucose entry into the TCA cycle. Such chronic activation of mTORC1 leads to compensatory increases in anaplerotic pathways to replenish TCA intermediates that are consumed for biosynthetic purposes. These phenotypes reveal a fundamental role for the GATOR1 complex in the homeostatic regulation of mitochondrial functions (biosynthesis versus ATP) to mediate carbohydrate utilization in muscle.
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Affiliation(s)
- Paul A Dutchak
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry and Neuroscience, Université Laval, Québec, QC, Canada; CERVO Brain Research Centre, 2601 Chemin de la Canardière, Québec, QC, Canada
| | - Sandi J Estill-Terpack
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Abigail A Plec
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaozheng Zhao
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Chendong Yang
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jun Chen
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Bookyung Ko
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ralph J Deberardinis
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yonghao Yu
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Benjamin P Tu
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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22
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Wei Y, Bettedi L, Ting CY, Kim K, Zhang Y, Cai J, Lilly MA. The GATOR complex regulates an essential response to meiotic double-stranded breaks in Drosophila. eLife 2019; 8:e42149. [PMID: 31650955 PMCID: PMC6834368 DOI: 10.7554/elife.42149] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 10/13/2019] [Indexed: 01/18/2023] Open
Abstract
The TORC1 regulator GATOR1/SEACIT controls meiotic entry and early meiotic events in yeast. However, how metabolic pathways influence meiotic progression in metazoans remains poorly understood. Here we examine the role of the TORC1 regulators GATOR1 and GATOR2 in the response to meiotic double-stranded breaks (DSB) during Drosophila oogenesis. We find that in mutants of the GATOR2 component mio, meiotic DSBs trigger the constitutive downregulation of TORC1 activity and a permanent arrest in oocyte growth. Conversely, in GATOR1 mutants, high TORC1 activity results in the delayed repair of meiotic DSBs and the hyperactivation of p53. Unexpectedly, we found that GATOR1 inhibits retrotransposon expression in the presence of meiotic DSBs in a pathway that functions in parallel to p53. Thus, our studies have revealed a link between oocyte metabolism, the repair of meiotic DSBs and retrotransposon expression.
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Affiliation(s)
- Youheng Wei
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
- College of Bioscience and BiotechnologyYangzhou UniversityYangzhouChina
| | - Lucia Bettedi
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Chun-Yuan Ting
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Kuikwon Kim
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Yingbiao Zhang
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Jiadong Cai
- College of Bioscience and BiotechnologyYangzhou UniversityYangzhouChina
| | - Mary A Lilly
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
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23
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Froese DS, Fowler B, Baumgartner MR. Vitamin B 12 , folate, and the methionine remethylation cycle-biochemistry, pathways, and regulation. J Inherit Metab Dis 2019; 42:673-685. [PMID: 30693532 DOI: 10.1002/jimd.12009] [Citation(s) in RCA: 244] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 09/27/2018] [Accepted: 10/19/2018] [Indexed: 12/16/2022]
Abstract
Vitamin B12 (cobalamin, Cbl) is a nutrient essential to human health. Due to its complex structure and dual cofactor forms, Cbl undergoes a complicated series of absorptive and processing steps before serving as cofactor for the enzymes methylmalonyl-CoA mutase and methionine synthase. Methylmalonyl-CoA mutase is required for the catabolism of certain (branched-chain) amino acids into an anaplerotic substrate in the mitochondrion, and dysfunction of the enzyme itself or in production of its cofactor adenosyl-Cbl result in an inability to successfully undergo protein catabolism with concomitant mitochondrial energy disruption. Methionine synthase catalyzes the methyl-Cbl dependent (re)methylation of homocysteine to methionine within the methionine cycle; a reaction required to produce this essential amino acid and generate S-adenosylmethionine, the most important cellular methyl-donor. Disruption of methionine synthase has wide-ranging implications for all methylation-dependent reactions, including epigenetic modification, but also for the intracellular folate pathway, since methionine synthase uses 5-methyltetrahydrofolate as a one-carbon donor. Folate-bound one-carbon units are also required for deoxythymidine monophosphate and de novo purine synthesis; therefore, the flow of single carbon units to each of these pathways must be regulated based on cellular needs. This review provides an overview on Cbl metabolism with a brief description of absorption and intracellular metabolic pathways. It also provides a description of folate-mediated one-carbon metabolism and its intersection with Cbl at the methionine cycle. Finally, a summary of recent advances in understanding of how both pathways are regulated is presented.
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Affiliation(s)
- D Sean Froese
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zurich, Switzerland
| | - Brian Fowler
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zurich, Switzerland
| | - Matthias R Baumgartner
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zurich, Switzerland
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24
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Kim JK, Lee JH. Mechanistic Target of Rapamycin Pathway in Epileptic Disorders. J Korean Neurosurg Soc 2019; 62:272-287. [PMID: 31085953 PMCID: PMC6514310 DOI: 10.3340/jkns.2019.0027] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 03/12/2019] [Indexed: 12/19/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR) pathway coordinates the metabolic activity of eukaryotic cells through environmental signals, including nutrients, energy, growth factors, and oxygen. In the nervous system, the mTOR pathway regulates fundamental biological processes associated with neural development and neurodegeneration. Intriguingly, genes that constitute the mTOR pathway have been found to be germline and somatic mutation from patients with various epileptic disorders. Hyperactivation of the mTOR pathway due to said mutations has garnered increasing attention as culprits of these conditions : somatic mutations, in particular, in epileptic foci have recently been identified as a major genetic cause of intractable focal epilepsy, such as focal cortical dysplasia. Meanwhile, epilepsy models with aberrant activation of the mTOR pathway have helped elucidate the role of the mTOR pathway in epileptogenesis, and evidence from epilepsy models of human mutations recapitulating the features of epileptic patients has indicated that mTOR inhibitors may be of use in treating epilepsy associated with mutations in mTOR pathway genes. Here, we review recent advances in the molecular and genetic understanding of mTOR signaling in epileptic disorders. In particular, we focus on the development of and limitations to therapies targeting the mTOR pathway to treat epileptic seizures. We also discuss future perspectives on mTOR inhibition therapies and special diagnostic methods for intractable epilepsies caused by brain somatic mutations.
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Affiliation(s)
- Jang Keun Kim
- Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Jeong Ho Lee
- Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea.,Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
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25
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Marsan E, Baulac S. Review: Mechanistic target of rapamycin (mTOR) pathway, focal cortical dysplasia and epilepsy. Neuropathol Appl Neurobiol 2019; 44:6-17. [PMID: 29359340 DOI: 10.1111/nan.12463] [Citation(s) in RCA: 134] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/17/2018] [Indexed: 12/19/2022]
Abstract
Over the last decade, there has been increasing evidence that hyperactivation of the mechanistic target of rapamycin (mTOR) pathway is a hallmark of malformations of cortical development such as focal cortical dysplasia (FCD) or hemimegalencephaly. The mTOR pathway governs protein and lipid synthesis, cell growth and proliferation as well as metabolism and autophagy. The molecular genetic aetiology of mTOR hyperactivation has only been recently clarified. This article will review the current and still evolving genetic advances in the elucidation of the molecular basis of FCD. Activating somatic mutations in the MTOR gene are to date the most frequent mutations found in FCD brain specimens.
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Affiliation(s)
- E Marsan
- Department of Genetics and Cytogenetics, AP-HP, Institut du Cerveau et de la Moelle Epinière (ICM) - Hôpital Pitié-Salpêtrière, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Inserm U1127, CNRS UMR 7225, Paris, France
| | - S Baulac
- Department of Genetics and Cytogenetics, AP-HP, Institut du Cerveau et de la Moelle Epinière (ICM) - Hôpital Pitié-Salpêtrière, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Inserm U1127, CNRS UMR 7225, Paris, France
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26
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Graber TG, Fry CS, Brightwell CR, Moro T, Maroto R, Bhattarai N, Porter C, Wakamiya M, Rasmussen BB. Skeletal muscle-specific knockout of DEP domain containing 5 protein increases mTORC1 signaling, muscle cell hypertrophy, and mitochondrial respiration. J Biol Chem 2019; 294:4091-4102. [PMID: 30635399 DOI: 10.1074/jbc.ra118.005970] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 01/09/2019] [Indexed: 11/06/2022] Open
Abstract
mTORC1 regulates protein synthesis and in turn is regulated by growth factors, energy status, and amino acid availability. In kidney cell (HEK293-T) culture, the GAP activity toward RAG (GATOR1) protein complex suppresses activation of the RAG A/B-RAG C/D heterodimer when amino acids are insufficient. During amino acid sufficiency, the RAG heterodimer recruits mTORC1 to the lysosomal membrane where its interaction with Ras homolog enriched in brain (Rheb) stimulates mTORC1's kinase activity. The DEP domain containing 5 (DEPDC5) protein, a GATOR1 subunit, causes familial focal epilepsy when mutated, and global knockout of the Depdc5 gene is embryonically lethal. To study the function of DEPDC5 in skeletal muscle, we generated a muscle-specific inducible Depdc5 knockout mouse, hypothesizing that knocking out Depdc5 in muscle would make mTORC1 constitutively active, causing hypertrophy and improving muscle function. Examining mTORC1 signaling, morphology, mitochondrial respiratory capacity, contractile function, and applied physical function (e.g. rotarod, treadmill, grip test, and wheel running), we observed that mTORC1 activity was significantly higher in knockout (KO) mice, indicated by the increased phosphorylation of mTOR and its downstream effectors (by 118% for p-mTOR/mTOR, 114% for p-S6K1/S6K1, and 35% for p-4E-BP1/4E-BP1). The KO animals also exhibited soleus muscle cell hypertrophy and a 2.5-fold increase in mitochondrial respiratory capacity. However, contrary to our hypothesis, neither physical nor contractile function improved. In conclusion, DEPDC5 depletion in adult skeletal muscle removes GATOR1 inhibition of mTORC1, resulting in muscle hypertrophy and increased mitochondrial respiration, but does not improve overall muscle quality and function.
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Affiliation(s)
- Ted G Graber
- From the Division of Rehabilitation Sciences.,the Department of Nutrition and Metabolism
| | | | | | | | | | | | | | - Maki Wakamiya
- the Transgenics Core Facility, University of Texas Medical Branch, Galveston, Texas 77555
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27
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Chen Z, Jiang Q, Zhu P, Chen Y, Xie X, Du Z, Jiang L, Tang W. NPRL2 enhances autophagy and the resistance to Everolimus in castration-resistant prostate cancer. Prostate 2019; 79:44-53. [PMID: 30178500 DOI: 10.1002/pros.23709] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 08/01/2018] [Indexed: 01/09/2023]
Abstract
BACKGROUND Nitrogen permease regulator-like 2 (NPRL2) is reported to be a tumor suppressor candidate gene and involved in the mTOR signaling and drug resistance in several cancers. However, the role of NPRL2 in regulating the resistance to Everolimus (EVS), an inhibitor of the mTOR, in castration-resistant prostate cancer (CRPC) is still unclear. Therefore, in present study, we evaluated the role of NPRL2 and its potential resistance to EVS in CRPC. METHODS NPRL2 expression levels in prostate tissues, including benign prostate hyperplasia (BPH) tissues, primary prostate cancer (PCa) tissues, CRPC tissues, and several PCa cell lines (LNCaP, PC3, and enzalutamide-resistant LNCaP, named LNPER) were be evaluated by immunohistochemistry, RT-PCR, and Western blot. Furthermore, we employed the loss or gain function of NPRL2 to determine the role of NPRL2 in regulating the proliferation, sensitivity to EVS, the mTOR signaling, autophagy in CRPC. Lastly, relationship between NPRL2 expression level and the efficacy of EVS were evaluated in mice tumor xenograft models. RESULTS NPRL2 expression level is upregulated in PCa, particularly in the CRPC. NPRL2 over-expression promoted the proliferation, resistance to EVS, and NPRL2 silencing inhibited proliferation, enhanced sensitivity to EVS in PC3 and LNPER cells. Moreover, NPRL2-silencing increased the activity of mTOR signaling, and the autophagy attenuation induced by NPRL2-silencing in EVS-treated CRPC cells was associated with the increase of apoptosis. In addition, the growth prevention of NPRL2-silencing LNPER tumors in mice induced by EVS-treatment was associated with the autophagy attenuation and apoptosis increase. CONCLUSIONS NPRL2 may act as a pro-growth factor in PCa. The high levels of NPRL2 expression in CRPC promote resistance to EVS by enhancing autophagy. NPRL2 may be a new therapeutic target for intervention of CRPC and a biomarker for predicting resistance to EVS in CRPC.
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Affiliation(s)
- Zhixiong Chen
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P. R. China
| | - Qilong Jiang
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P. R. China
| | - Pingyu Zhu
- Department of Urology, The Affiliated Hospital of North Sichuan Medical College,, Nanchong, P. R. China
| | - Yanlin Chen
- Department of Pathology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P. R. China
| | - Xuemei Xie
- Molecular and Pathological Diagnosis Center, Chongqing Medical University, Chongqing, P. R. China
| | - Zhongbo Du
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P. R. China
| | - Li Jiang
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P. R. China
| | - Wei Tang
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P. R. China
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28
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Bourdeau Julien I, Sephton CF, Dutchak PA. Metabolic Networks Influencing Skeletal Muscle Fiber Composition. Front Cell Dev Biol 2018; 6:125. [PMID: 30324104 PMCID: PMC6172607 DOI: 10.3389/fcell.2018.00125] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 09/10/2018] [Indexed: 12/19/2022] Open
Abstract
Advancements in metabolomic and genomic research tools are revealing new insights into how metabolic networks can influence skeletal muscle fiber composition. In this mini-review, we summarize the recent progress of metabolite-dependent signaling pathways and transcriptional regulators that control glycolytic and oxidative metabolism and ultimately influence the type of fibers in muscle depots. These mechanisms expand the role of metabolites beyond that of basic building blocks of cellular components, and illustrate how particular metabolites can take an active role in regulating metabolic homeostasis and fiber adaptation. As new metabolite-dependent mechanisms emerge, ongoing metabolomic studies have begun to help explain why distinct metabolic pathways are used in different biological contexts and widen the view of seminal observations like the Warburg effect.
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Affiliation(s)
- Isabelle Bourdeau Julien
- Department of Psychiatry and Neuroscience, Université Laval, Quebec, QC, Canada.,CERVO Brain Research Centre, Quebec, QC, Canada
| | - Chantelle F Sephton
- Department of Psychiatry and Neuroscience, Université Laval, Quebec, QC, Canada.,CERVO Brain Research Centre, Quebec, QC, Canada
| | - Paul A Dutchak
- Department of Psychiatry and Neuroscience, Université Laval, Quebec, QC, Canada.,CERVO Brain Research Centre, Quebec, QC, Canada
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29
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High expression of NPRL2 is linked to poor prognosis in patients with prostate cancer. Hum Pathol 2018; 76:141-148. [DOI: 10.1016/j.humpath.2018.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 02/02/2018] [Accepted: 02/07/2018] [Indexed: 02/05/2023]
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30
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Dong Z, Sinha R, Richie JP. Disease prevention and delayed aging by dietary sulfur amino acid restriction: translational implications. Ann N Y Acad Sci 2018; 1418:44-55. [PMID: 29399808 DOI: 10.1111/nyas.13584] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/21/2017] [Accepted: 11/27/2017] [Indexed: 01/01/2023]
Abstract
Sulfur amino acids (SAAs) play numerous critical roles in metabolism and overall health maintenance. Preclinical studies have demonstrated that SAA-restricted diets have many beneficial effects, including extending life span and preventing the development of a variety of diseases. Dietary sulfur amino acid restriction (SAAR) is characterized by chronic restrictions of methionine and cysteine but not calories and is associated with reductions in body weight, adiposity and oxidative stress, and metabolic changes in adipose tissue and liver resulting in enhanced insulin sensitivity and energy expenditure. SAAR-induced changes in blood biomarkers include reductions in insulin, insulin-like growth factor-1, glucose, and leptin and increases in adiponectin and fibroblast growth factor 21. On the basis of these preclinical data, SAAR may also have similar benefits in humans. While little is known of the translational significance of SAAR, its potential feasibility in humans is supported by findings of its effectiveness in rodents, even when initiated in adult animals. To date, there have been no controlled feeding studies of SAAR in humans; however, there have been numerous relevant epidemiologic and disease-based clinical investigations reported. Here, we summarize observations from these clinical investigations to provide insight into the potential effectiveness of SAAR for humans.
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Affiliation(s)
- Zhen Dong
- Department of Public Health Sciences, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Raghu Sinha
- Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - John P Richie
- Department of Public Health Sciences, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
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31
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Liao M, Wang J. Mechanisms of Hematopoietic Stem Cell Ageing and Targets for Hematopoietic Tumour Prevention. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1086:117-140. [PMID: 30232756 DOI: 10.1007/978-981-13-1117-8_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hematopoietic stem cells represent a rare population in the bone marrow, with the capacity of generating all blood lineage and themselves at the same time. With aging, the reconstitution capacity of hematopoietic stem cells decreases accompanying with differentiation skewing wherein the myeloid branch dominates in both mouse and human. In recent years, various molecular mechanisms that induce functional decline of HSC during aging were disclosed including DNA damage accumulation, metabolic alteration, defects in protein homeostasis, and aging-induced changes in the blood circulatory environment. Deciphering the nature of HSC aging could improve our knowledge of HSC aging-related diseases and furthermore promote the developing of therapeutic interventions for human HSC aging and diseases.
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Affiliation(s)
- Min Liao
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Jianwei Wang
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China.
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32
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Ma Y, Silveri L, LaCava J, Dokudovskaya S. Tumor suppressor NPRL2 induces ROS production and DNA damage response. Sci Rep 2017; 7:15311. [PMID: 29127423 PMCID: PMC5681675 DOI: 10.1038/s41598-017-15497-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 10/23/2017] [Indexed: 02/07/2023] Open
Abstract
The SEA/GATOR complex is an essential regulator of the mTORC1 pathway. In mammals the GATOR1 complex is composed of the proteins DEPDC5, NPRL2 and NPRL3. GATOR1 serves as an mTORC1 inhibitor and activates the mTORC1-modulating RagA GTPase. However, several GATOR members have mTORC1 independent functions. Here we characterize mammalian cells overexpressing the GATOR1 component NPRL2. We demonstrate that, in the cells with active p53, ectopic expression of NPRL2 induces NOX2-dependent production of reactive oxygen species and DNA damage. Overexpressed NPRL2 accumulates in the nucleus, together with apoptosis-inducing factor (AIF). These events are accompanied by phosphorylation of p53, activation of a DNA-damage response and cell cycle arrest in G1 phase, followed by apoptosis. In the cells negative for active p53, NPRL2 ectopic expression leads to activation of CHK1 or CHK2 kinases and cell cycle arrest in S or G2/M phases. Combined, these results demonstrate a new role for the NPRL2, distinct from its function in mTORC1 regulation.
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Affiliation(s)
- Yinxing Ma
- CNRS UMR 8126, Université Paris-Sud 11, Institut Gustave Roussy, 114, rue Edouard Vaillant, 94805, Villejuif, France
| | - Licia Silveri
- CNRS UMR 8126, Université Paris-Sud 11, Institut Gustave Roussy, 114, rue Edouard Vaillant, 94805, Villejuif, France
| | - John LaCava
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, New York, USA.,Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, 10016, USA
| | - Svetlana Dokudovskaya
- CNRS UMR 8126, Université Paris-Sud 11, Institut Gustave Roussy, 114, rue Edouard Vaillant, 94805, Villejuif, France.
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33
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Hughes J, Dawson R, Tea M, McAninch D, Piltz S, Jackson D, Stewart L, Ricos MG, Dibbens LM, Harvey NL, Thomas P. Knockout of the epilepsy gene Depdc5 in mice causes severe embryonic dysmorphology with hyperactivity of mTORC1 signalling. Sci Rep 2017; 7:12618. [PMID: 28974734 PMCID: PMC5626732 DOI: 10.1038/s41598-017-12574-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 09/08/2017] [Indexed: 12/15/2022] Open
Abstract
DEPDC5 mutations have recently been shown to cause epilepsy in humans. Evidence from in vitro studies has implicated DEPDC5 as a negative regulator of mTORC1 during amino acid insufficiency as part of the GATOR1 complex. To investigate the role of DEPDC5 in vivo we generated a null mouse model using targeted CRISPR mutagenesis. Depdc5 homozygotes display severe phenotypic defects between 12.5-15.5 dpc, including hypotrophy, anaemia, oedema, and cranial dysmorphology as well as blood and lymphatic vascular defects. mTORC1 hyperactivity was observed in the brain of knockout embryos and in fibroblasts and neurospheres isolated from knockout embryos and cultured in nutrient deprived conditions. Heterozygous mice appeared to be normal and we found no evidence of increased susceptibility to seizures or tumorigenesis. Together, these data support mTORC1 hyperactivation as the likely pathogenic mechanism that underpins DEPDC5 loss of function in humans and highlights the potential utility of mTORC1 inhibitors in the treatment of DEPDC5-associated epilepsy.
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Affiliation(s)
- James Hughes
- School of Biological Sciences, University of Adelaide, Adelaide, SA, AUS 5005, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, SA, AUS 5005, Australia
| | - Ruby Dawson
- School of Biological Sciences, University of Adelaide, Adelaide, SA, AUS 5005, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, SA, AUS 5005, Australia
| | - Melinda Tea
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, AUS 5000, Australia
| | - Dale McAninch
- School of Biological Sciences, University of Adelaide, Adelaide, SA, AUS 5005, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, SA, AUS 5005, Australia
| | - Sandra Piltz
- School of Biological Sciences, University of Adelaide, Adelaide, SA, AUS 5005, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, SA, AUS 5005, Australia
| | - Dominique Jackson
- School of Biological Sciences, University of Adelaide, Adelaide, SA, AUS 5005, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, SA, AUS 5005, Australia
| | - Laura Stewart
- School of Biological Sciences, University of Adelaide, Adelaide, SA, AUS 5005, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, SA, AUS 5005, Australia
| | - Michael G Ricos
- University of South Australia, Epilepsy Research Program, School of Pharmacy and Medical Sciences, Adelaide, SA, AUS 5000, Australia
| | - Leanne M Dibbens
- University of South Australia, Epilepsy Research Program, School of Pharmacy and Medical Sciences, Adelaide, SA, AUS 5000, Australia
| | - Natasha L Harvey
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, AUS 5000, Australia
| | - Paul Thomas
- School of Biological Sciences, University of Adelaide, Adelaide, SA, AUS 5005, Australia. .,Robinson Research Institute, University of Adelaide, Adelaide, SA, AUS 5005, Australia.
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Statin and Bisphosphonate Induce Starvation in Fast-Growing Cancer Cell Lines. Int J Mol Sci 2017; 18:ijms18091982. [PMID: 28914765 PMCID: PMC5618631 DOI: 10.3390/ijms18091982] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 09/04/2017] [Accepted: 09/11/2017] [Indexed: 12/11/2022] Open
Abstract
Statins and bisphosphonates are increasingly recognized as anti-cancer drugs, especially because of their cholesterol-lowering properties. However, these drugs act differently on various types of cancers. Thus, the aim of this study was to compare the effects of statins and bisphosphonates on the metabolism (NADP+/NADPH-relation) of highly proliferative tumor cell lines from different origins (PC-3 prostate carcinoma, MDA-MB-231 breast cancer, U-2 OS osteosarcoma) versus cells with a slower proliferation rate like MG-63 osteosarcoma cells. Global gene expression analysis revealed that after 6 days of treatment with pharmacologic doses of the statin simvastatin and of the bisphosphonate ibandronate, simvastatin regulated more than twice as many genes as ibandronate, including many genes associated with cell cycle progression. Upregulation of starvation-markers and a reduction of metabolism and associated NADPH production, an increase in autophagy, and a concomitant downregulation of H3K27 methylation was most significant in the fast-growing cancer cell lines. This study provides possible explanations for clinical observations indicating a higher sensitivity of rapidly proliferating tumors to statins and bisphosphonates.
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Ulianov SV, Galitsyna AA, Flyamer IM, Golov AK, Khrameeva EE, Imakaev MV, Abdennur NA, Gelfand MS, Gavrilov AA, Razin SV. Activation of the alpha-globin gene expression correlates with dramatic upregulation of nearby non-globin genes and changes in local and large-scale chromatin spatial structure. Epigenetics Chromatin 2017; 10:35. [PMID: 28693562 PMCID: PMC5504709 DOI: 10.1186/s13072-017-0142-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 07/03/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In homeotherms, the alpha-globin gene clusters are located within permanently open genome regions enriched in housekeeping genes. Terminal erythroid differentiation results in dramatic upregulation of alpha-globin genes making their expression comparable to the rRNA transcriptional output. Little is known about the influence of the erythroid-specific alpha-globin gene transcription outburst on adjacent, widely expressed genes and large-scale chromatin organization. Here, we have analyzed the total transcription output, the overall chromatin contact profile, and CTCF binding within the 2.7 Mb segment of chicken chromosome 14 harboring the alpha-globin gene cluster in cultured lymphoid cells and cultured erythroid cells before and after induction of terminal erythroid differentiation. RESULTS We found that, similarly to mammalian genome, the chicken genomes is organized in TADs and compartments. Full activation of the alpha-globin gene transcription in differentiated erythroid cells is correlated with upregulation of several adjacent housekeeping genes and the emergence of abundant intergenic transcription. An extended chromosome region encompassing the alpha-globin cluster becomes significantly decompacted in differentiated erythroid cells, and depleted in CTCF binding and CTCF-anchored chromatin loops, while the sub-TAD harboring alpha-globin gene cluster and the upstream major regulatory element (MRE) becomes highly enriched with chromatin interactions as compared to lymphoid and proliferating erythroid cells. The alpha-globin gene domain and the neighboring loci reside within the A-like chromatin compartment in both lymphoid and erythroid cells and become further segregated from the upstream gene desert upon terminal erythroid differentiation. CONCLUSIONS Our findings demonstrate that the effects of tissue-specific transcription activation are not restricted to the host genomic locus but affect the overall chromatin structure and transcriptional output of the encompassing topologically associating domain.
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Affiliation(s)
- Sergey V Ulianov
- Institute of Gene Biology of the Russian Academy of Sciences, Moscow, Russia 119334.,Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia 119992
| | - Aleksandra A Galitsyna
- Institute of Gene Biology of the Russian Academy of Sciences, Moscow, Russia 119334.,Faculty of Bioengineering and Bioinformatics, M.V. Lomonosov Moscow State University, Moscow, Russia 119992.,Institute for Information Transmission Problems (the Kharkevich Institute) of the Russian Academy of Sciences, Moscow, Russia 127051
| | - Ilya M Flyamer
- Institute of Gene Biology of the Russian Academy of Sciences, Moscow, Russia 119334.,Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia 119992.,MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Arkadiy K Golov
- Institute of Gene Biology of the Russian Academy of Sciences, Moscow, Russia 119334
| | - Ekaterina E Khrameeva
- Skolkovo Institute of Science and Technology, Skolkovo, Russia 143026.,Institute for Information Transmission Problems (the Kharkevich Institute) of the Russian Academy of Sciences, Moscow, Russia 127051
| | - Maxim V Imakaev
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
| | - Nezar A Abdennur
- Computational and Systems Biology Graduate Program, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Mikhail S Gelfand
- Faculty of Bioengineering and Bioinformatics, M.V. Lomonosov Moscow State University, Moscow, Russia 119992.,Skolkovo Institute of Science and Technology, Skolkovo, Russia 143026.,Institute for Information Transmission Problems (the Kharkevich Institute) of the Russian Academy of Sciences, Moscow, Russia 127051.,Faculty of Computer Science, Higher School of Economics, Moscow, Russia 125319
| | - Alexey A Gavrilov
- Institute of Gene Biology of the Russian Academy of Sciences, Moscow, Russia 119334
| | - Sergey V Razin
- Institute of Gene Biology of the Russian Academy of Sciences, Moscow, Russia 119334.,Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia 119992
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36
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Ye C, Sutter BM, Wang Y, Kuang Z, Tu BP. A Metabolic Function for Phospholipid and Histone Methylation. Mol Cell 2017; 66:180-193.e8. [PMID: 28366644 DOI: 10.1016/j.molcel.2017.02.026] [Citation(s) in RCA: 187] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 01/31/2017] [Accepted: 02/27/2017] [Indexed: 11/28/2022]
Abstract
S-adenosylmethionine (SAM) is the methyl donor for biological methylation modifications that regulate protein and nucleic acid functions. Here, we show that methylation of a phospholipid, phosphatidylethanolamine (PE), is a major consumer of SAM. The induction of phospholipid biosynthetic genes is accompanied by induction of the enzyme that hydrolyzes S-adenosylhomocysteine (SAH), a product and inhibitor of methyltransferases. Beyond its function for the synthesis of phosphatidylcholine (PC), the methylation of PE facilitates the turnover of SAM for the synthesis of cysteine and glutathione through transsulfuration. Strikingly, cells that lack PE methylation accumulate SAM, which leads to hypermethylation of histones and the major phosphatase PP2A, dependency on cysteine, and sensitivity to oxidative stress. Without PE methylation, particular sites on histones then become methyl sinks to enable the conversion of SAM to SAH. These findings reveal an unforeseen metabolic function for phospholipid and histone methylation intrinsic to the life of a cell.
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Affiliation(s)
- Cunqi Ye
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9038, USA
| | - Benjamin M Sutter
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9038, USA
| | - Yun Wang
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9038, USA
| | - Zheng Kuang
- Department of Immunology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9038, USA
| | - Benjamin P Tu
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9038, USA.
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Abstract
For almost all cells, nutrient availability, from glucose to amino acids, dictates their growth or developmental programs. This nutrient availability is closely coupled to the overall intracellular metabolic state of the cell. Therefore, cells have evolved diverse, robust and versatile modules to sense intracellular metabolic states, activate signaling outputs and regulate outcomes to these states. Yet, signaling and metabolism have been viewed as important but separate. This short review attempts to position aspects of intracellular signaling from a metabolic perspective, highlighting how conserved, core principles of metabolic sensing and signaling can emerge from an understanding of metabolic regulation. I briefly explain the nature of metabolic sensors, using the example of the AMP activated protein kinase (AMPK) as an "energy sensing" hub. Subsequently, I explore how specific central metabolites, particularly acetyl-CoA, but also S -adenosyl methionine and SAICAR, can act as signaling molecules. I extensively illustrate the nature of a metabolic signaling hub using the specific example of the Target of Rapamycin Complex 1 (TORC1), and amino acid sensing. A highlight is the emergence of the lysosome/vacuole as a metabolic and signaling hub. Finally, the need to expand our understanding of the intracellular dynamics (in concentration and localization) of several metabolites, and their signaling hubs is emphasized.
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Affiliation(s)
- Sunil Laxman
- Institute for Stem Cell Biology and Regenerative Medicine (inStem), NCBS Campus, GKVK, Bellary Road, Bangalore 560065, India
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38
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Wei Y, Reveal B, Cai W, Lilly MA. The GATOR1 Complex Regulates Metabolic Homeostasis and the Response to Nutrient Stress in Drosophila melanogaster. G3 (BETHESDA, MD.) 2016; 6:3859-3867. [PMID: 27672113 PMCID: PMC5144957 DOI: 10.1534/g3.116.035337] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 09/15/2016] [Indexed: 02/06/2023]
Abstract
TORC1 regulates metabolism and growth in response to a large array of upstream inputs. The evolutionarily conserved trimeric GATOR1 complex inhibits TORC1 activity in response to amino acid limitation. In humans, the GATOR1 complex has been implicated in a wide array of pathologies including cancer and hereditary forms of epilepsy. However, the precise role of GATOR1 in animal physiology remains largely undefined. Here, we characterize null mutants of the GATOR1 components nprl2, nprl3, and iml1 in Drosophila melanogaster We demonstrate that all three mutants have inappropriately high baseline levels of TORC1 activity and decreased adult viability. Consistent with increased TORC1 activity, GATOR1 mutants exhibit a cell autonomous increase in cell growth. Notably, escaper nprl2 and nprl3 mutant adults have a profound locomotion defect. In line with a nonautonomous role in the regulation of systemic metabolism, expressing the Nprl3 protein in the fat body, a nutrient storage organ, and hemocytes but not muscles and neurons rescues the motility of nprl3 mutants. Finally, we show that nprl2 and nprl3 mutants fail to activate autophagy in response to amino acid limitation and are extremely sensitive to both amino acid and complete starvation. Thus, in Drosophila, in addition to maintaining baseline levels of TORC1 activity, the GATOR1 complex has retained a critical role in the response to nutrient stress. In summary, the TORC1 inhibitor GATOR1 contributes to multiple aspects of the development and physiology of Drosophila.
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Affiliation(s)
- Youheng Wei
- Cell Biology and Neurobiology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Brad Reveal
- Cell Biology and Neurobiology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Weili Cai
- Cell Biology and Neurobiology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Mary A Lilly
- Cell Biology and Neurobiology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
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39
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Hannibal L, Lysne V, Bjørke-Monsen AL, Behringer S, Grünert SC, Spiekerkoetter U, Jacobsen DW, Blom HJ. Biomarkers and Algorithms for the Diagnosis of Vitamin B12 Deficiency. Front Mol Biosci 2016; 3:27. [PMID: 27446930 PMCID: PMC4921487 DOI: 10.3389/fmolb.2016.00027] [Citation(s) in RCA: 199] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/07/2016] [Indexed: 12/12/2022] Open
Abstract
Vitamin B12 (cobalamin, Cbl, B12) is an indispensable water-soluble micronutrient that serves as a coenzyme for cytosolic methionine synthase (MS) and mitochondrial methylmalonyl-CoA mutase (MCM). Deficiency of Cbl, whether nutritional or due to inborn errors of Cbl metabolism, inactivate MS and MCM leading to the accumulation of homocysteine (Hcy) and methylmalonic acid (MMA), respectively. In conjunction with total B12 and its bioactive protein-bound form, holo-transcobalamin (holo-TC), Hcy, and MMA are the preferred serum biomarkers utilized to determine B12 status. Clinically, vitamin B12 deficiency leads to neurological deterioration and megaloblastic anemia, and, if left untreated, to death. Subclinical vitamin B12 deficiency (usually defined as a total serum B12 of <200 pmol/L) presents asymptomatically or with rather subtle generic symptoms that oftentimes are mistakenly ascribed to unrelated disorders. Numerous studies have now established that serum vitamin B12 has limited diagnostic value as a stand-alone marker. Low serum levels of vitamin B12 not always represent deficiency, and likewise, severe functional deficiency of the micronutrient has been documented in the presence of normal and even high levels of serum vitamin B12. This review discusses the usefulness and limitations of current biomarkers of B12 status in newborn screening, infant and adult diagnostics, the algorithms utilized to diagnose B12 deficiency and unusual findings of vitamin B12 status in various human disorders.
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Affiliation(s)
- Luciana Hannibal
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg Freiburg, Germany
| | - Vegard Lysne
- Department of Clinical Sciences, University of Bergen Bergen, Norway
| | | | - Sidney Behringer
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg Freiburg, Germany
| | - Sarah C Grünert
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg Freiburg, Germany
| | - Ute Spiekerkoetter
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg Freiburg, Germany
| | - Donald W Jacobsen
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Cleveland, OH, USA
| | - Henk J Blom
- Laboratory of Clinical Biochemistry and Metabolism, Department for Pediatrics, Medical Center, University of Freiburg Freiburg, Germany
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40
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Marsan E, Ishida S, Schramm A, Weckhuysen S, Muraca G, Lecas S, Liang N, Treins C, Pende M, Roussel D, Le Van Quyen M, Mashimo T, Kaneko T, Yamamoto T, Sakuma T, Mahon S, Miles R, Leguern E, Charpier S, Baulac S. Depdc5 knockout rat: A novel model of mTORopathy. Neurobiol Dis 2016; 89:180-9. [PMID: 26873552 DOI: 10.1016/j.nbd.2016.02.010] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 02/07/2016] [Indexed: 12/23/2022] Open
Abstract
DEP-domain containing 5 (DEPDC5), encoding a repressor of the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway, has recently emerged as a major gene mutated in familial focal epilepsies and focal cortical dysplasia. Here we established a global knockout rat using TALEN technology to investigate in vivo the impact of Depdc5-deficiency. Homozygous Depdc5(-/-) embryos died from embryonic day 14.5 due to a global growth delay. Constitutive mTORC1 hyperactivation was evidenced in the brains and in cultured fibroblasts of Depdc5(-/-) embryos, as reflected by enhanced phosphorylation of its downstream effectors S6K1 and rpS6. Consistently, prenatal treatment with mTORC1 inhibitor rapamycin rescued the phenotype of Depdc5(-/-) embryos. Heterozygous Depdc5(+/-) rats developed normally and exhibited no spontaneous electroclinical seizures, but had altered cortical neuron excitability and firing patterns. Depdc5(+/-) rats displayed cortical cytomegalic dysmorphic neurons and balloon-like cells strongly expressing phosphorylated rpS6, indicative of mTORC1 upregulation, and not observed after prenatal rapamycin treatment. These neuropathological abnormalities are reminiscent of the hallmark brain pathology of human focal cortical dysplasia. Altogether, Depdc5 knockout rats exhibit multiple features of rodent models of mTORopathies, and thus, stand as a relevant model to study their underlying pathogenic mechanisms.
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Affiliation(s)
- Elise Marsan
- INSERM, U1127, ICM, F-75013 Paris, France; CNRS, UMR 7225, ICM, F-75013 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Saeko Ishida
- INSERM, U1127, ICM, F-75013 Paris, France; CNRS, UMR 7225, ICM, F-75013 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Adrien Schramm
- INSERM, U1127, ICM, F-75013 Paris, France; CNRS, UMR 7225, ICM, F-75013 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Sarah Weckhuysen
- INSERM, U1127, ICM, F-75013 Paris, France; CNRS, UMR 7225, ICM, F-75013 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Giuseppe Muraca
- INSERM, U1127, ICM, F-75013 Paris, France; CNRS, UMR 7225, ICM, F-75013 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Sarah Lecas
- INSERM, U1127, ICM, F-75013 Paris, France; CNRS, UMR 7225, ICM, F-75013 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Ning Liang
- Institut Necker-Enfants Malades, CS 61431, Paris, France; INSERM, U1151, F-75014 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, F-75006 Paris, France
| | - Caroline Treins
- Institut Necker-Enfants Malades, CS 61431, Paris, France; INSERM, U1151, F-75014 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, F-75006 Paris, France
| | - Mario Pende
- Institut Necker-Enfants Malades, CS 61431, Paris, France; INSERM, U1151, F-75014 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, F-75006 Paris, France
| | - Delphine Roussel
- INSERM, U1127, ICM, F-75013 Paris, France; CNRS, UMR 7225, ICM, F-75013 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Michel Le Van Quyen
- INSERM, U1127, ICM, F-75013 Paris, France; CNRS, UMR 7225, ICM, F-75013 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Tomoji Mashimo
- Institute of Experimental Animal Sciences, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan
| | - Takehito Kaneko
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Takashi Yamamoto
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Hiroshima 739-8526, Japan
| | - Tetsushi Sakuma
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Hiroshima 739-8526, Japan
| | - Séverine Mahon
- INSERM, U1127, ICM, F-75013 Paris, France; CNRS, UMR 7225, ICM, F-75013 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Richard Miles
- INSERM, U1127, ICM, F-75013 Paris, France; CNRS, UMR 7225, ICM, F-75013 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Eric Leguern
- INSERM, U1127, ICM, F-75013 Paris, France; CNRS, UMR 7225, ICM, F-75013 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France; Department of Genetics, Pitié-Salpêtrière Hospital, Public Hospital Network of Paris, Paris, France
| | - Stéphane Charpier
- INSERM, U1127, ICM, F-75013 Paris, France; CNRS, UMR 7225, ICM, F-75013 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Stéphanie Baulac
- INSERM, U1127, ICM, F-75013 Paris, France; CNRS, UMR 7225, ICM, F-75013 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France; Department of Genetics, Pitié-Salpêtrière Hospital, Public Hospital Network of Paris, Paris, France.
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41
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Baulac S. mTOR signaling pathway genes in focal epilepsies. PROGRESS IN BRAIN RESEARCH 2016; 226:61-79. [DOI: 10.1016/bs.pbr.2016.04.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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