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Gai Z, Hu S, He Y, Yan S, Wang R, Gong G, Zhao J. L-arginine alleviates heat stress-induced mammary gland injury through modulating CASTOR1-mTORC1 axis mediated mitochondrial homeostasis. Sci Total Environ 2024; 926:172017. [PMID: 38552976 DOI: 10.1016/j.scitotenv.2024.172017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 03/18/2024] [Accepted: 03/25/2024] [Indexed: 04/06/2024]
Abstract
As global warming intensifies, extreme heat is becoming increasingly frequent. These extreme heatwaves have decreased the milk production of dairy animals such as cows and goats and have caused significant damage to the entire dairy industry. It is known that heat stress (HS) can induce the apoptosis and autophagy of mammary epithelial cells (MECs), leading to a decrease in lactating MECs. L-arginine can effectively attenuate HS-induced decreases in milk yield, but the exact mechanisms are not fully understood. In this study, we found that HS upregulated the arginine sensor CASTOR1 in mouse MECs. Arginine activated mTORC1 activity through CASTOR1 and promoted mitochondrial biogenesis through the mTORC1/PGC-1α/NRF1 pathway. Moreover, arginine inhibited mitophagy through the CASTOR1/PINK1/Parkin pathway. Mitochondrial homeostasis ensures ATP synthesis and a stable cellular redox state for MECs under HS, further alleviating HS-induced damage and improving the lactation performance of MECs. In conclusion, these findings reveal the molecular mechanisms by which L-arginine relieves HS-induced mammary gland injury, and suggest that the intake of arginine-based feeds or feed additives is a promising method to increase the milk yield of dairy animals in extreme heat conditions.
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Affiliation(s)
- Zhongchao Gai
- School of Food Science & Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Songhao Hu
- School of Food Science & Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Yujiao He
- School of Food Science & Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Sijia Yan
- School of Food Science & Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Ranran Wang
- School of Food Science & Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Guoli Gong
- School of Food Science & Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China.
| | - Jieqiong Zhao
- Department of Cardiology, The Second Affiliated Hospital of Air Force Medical University, Xi'an 710038, China.
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Liu YJ, Wang JY, Zhang XL, Jiang LL, Hu HY. Ataxin-2 sequesters Raptor into aggregates and impairs cellular mTORC1 signaling. FEBS J 2024; 291:1795-1812. [PMID: 38308810 DOI: 10.1111/febs.17081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 11/28/2023] [Accepted: 01/26/2024] [Indexed: 02/05/2024]
Abstract
Ataxin-2 (Atx2) is a polyglutamine (polyQ) protein, in which abnormal expansion of the polyQ tract can trigger protein aggregation and consequently cause spinocerebellar ataxia type 2 (SCA2), but the mechanism underlying how Atx2 aggregation leads to proteinopathy remains elusive. Here, we investigate the molecular mechanism and cellular consequences of Atx2 aggregation by molecular cell biology approaches. We have revealed that either normal or polyQ-expanded Atx2 can sequester Raptor, a component of mammalian target of rapamycin complex 1 (mTORC1), into aggregates based on their specific interaction. Further research indicates that the polyQ tract and the N-terminal region (residues 1-784) of Atx2 are responsible for the specific sequestration. Moreover, this sequestration leads to suppression of the mTORC1 activity as represented by down-regulation of phosphorylated P70S6K, which can be reversed by overexpression of Raptor. As mTORC1 is a key regulator of autophagy, Atx2 aggregation and sequestration also induces autophagy by upregulating LC3-II and reducing phosphorylated ULK1 levels. This study proposes that Atx2 sequesters Raptor into aggregates, thereby impairing cellular mTORC1 signaling and inducing autophagy, and will be beneficial for a better understanding of the pathogenesis of SCA2 and other polyQ diseases.
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Affiliation(s)
- Ya-Jun Liu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jian-Yang Wang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xiang-Le Zhang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Lei-Lei Jiang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Hong-Yu Hu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
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Raevsky A, Kovalenko O, Bulgakov E, Sharifi M, Volochnyuk D, Tukalo M. Developing a comprehensive solution aimed to disrupt LARS1/RagD protein-protein interaction. J Biomol Struct Dyn 2024; 42:747-758. [PMID: 36995308 DOI: 10.1080/07391102.2023.2194996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 03/18/2023] [Indexed: 03/31/2023]
Abstract
Aminoacyl-tRNA synthetases are crucial enzymes involved in protein synthesis and various cellular physiological reactions. Aside from their standard role in linking amino acids to the corresponding tRNAs, they also impact protein homeostasis by controlling the level of soluble amino acids within the cell. For instance, leucyl-tRNA synthetase (LARS1) acts as a leucine sensor for the mammalian target of rapamycin complex 1 (mTORC1), and may also function as a probable GTPase-activating protein (GAP) for the RagD subunit of the heteromeric activator of mTORC1. In turn, mTORC1 regulates cellular processes, such as protein synthesis, autophagy, and cell growth, and is implicated in various human diseases including cancer, obesity, diabetes, and neurodegeneration. Hence, inhibitors of mTORC1 or a deregulated mTORC1 pathway may offer potential cancer therapies. In this study, we investigated the structural requirements for preventing the sensing and signal transmission from LARS to mTORC1. Building upon recent studies on mTORC1 regulation activation by leucine, we lay the foundation for the development of chemotherapeutic agents against mTORC1 that can overcome resistance to rapamycin. Using a combination of in-silico approaches to develop and validate an alternative interaction model, discussing its benefits and advancements. Finally, we identified a set of compounds ready for testing to prevent LARS1/RagD protein-protein interactions. We establish a basis for creating chemotherapeutic drugs targeting mTORC1, which can conquer resistance to rapamycin. We utilize in-silico methods to generate and confirm an alternative interaction model, outlining its advantages and improvements, and pinpoint a group of novel substances that can prevent LARS1/RagD interactions.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Alexey Raevsky
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv, Ukraine
- Institute of Food Biotechnology and Genomics, National Academy of Sciences of Ukraine, Kyiv, Ukraine
- Enamine Ltd, Kyiv, Ukraine
| | - Oksana Kovalenko
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Elijah Bulgakov
- Institute of Food Biotechnology and Genomics, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | | | - Dmityi Volochnyuk
- Enamine Ltd, Kyiv, Ukraine
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
| | - Michael Tukalo
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv, Ukraine
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Accogli A, Lin SJ, Severino M, Kim SH, Huang K, Rocca C, Landsverk M, Zaki MS, Al-Maawali A, Srinivasan VM, Al-Thihli K, Schaefer GB, Davis M, Tonduti D, Doneda C, Marten LM, Mühlhausen C, Gomez M, Lamantea E, Mena R, Nizon M, Procaccio V, Begtrup A, Telegrafi A, Cui H, Schulz HL, Mohr J, Biskup S, Loos MA, Aráoz HV, Salpietro V, Keppen LD, Chitre M, Petree C, Raymond L, Vogt J, Sawyer LB, Basinger AA, Pedersen SV, Pearson TS, Grange DK, Lingappa L, McDunnah P, Horvath R, Cognè B, Isidor B, Hahn A, Gripp KW, Jafarnejad SM, Østergaard E, Prada CE, Ghezzi D, Gowda VK, Taylor RW, Sonenberg N, Houlden H, Sissler M, Varshney GK, Maroofian R. Clinical, neuroradiological, and molecular characterization of mitochondrial threonyl-tRNA-synthetase (TARS2)-related disorder. Genet Med 2023; 25:100938. [PMID: 37454282 DOI: 10.1016/j.gim.2023.100938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 07/11/2023] [Accepted: 07/11/2023] [Indexed: 07/18/2023] Open
Abstract
PURPOSE Biallelic variants in TARS2, encoding the mitochondrial threonyl-tRNA-synthetase, have been reported in a small group of individuals displaying a neurodevelopmental phenotype but with limited neuroradiological data and insufficient evidence for causality of the variants. METHODS Exome or genome sequencing was carried out in 15 families. Clinical and neuroradiological evaluation was performed for all affected individuals, including review of 10 previously reported individuals. The pathogenicity of TARS2 variants was evaluated using in vitro assays and a zebrafish model. RESULTS We report 18 new individuals harboring biallelic TARS2 variants. Phenotypically, these individuals show developmental delay/intellectual disability, regression, cerebellar and cerebral atrophy, basal ganglia signal alterations, hypotonia, cerebellar signs, and increased blood lactate. In vitro studies showed that variants within the TARS2301-381 region had decreased binding to Rag GTPases, likely impairing mTORC1 activity. The zebrafish model recapitulated key features of the human phenotype and unraveled dysregulation of downstream targets of mTORC1 signaling. Functional testing of the variants confirmed the pathogenicity in a zebrafish model. CONCLUSION We define the clinico-radiological spectrum of TARS2-related mitochondrial disease, unveil the likely involvement of the mTORC1 signaling pathway as a distinct molecular mechanism, and establish a TARS2 zebrafish model as an important tool to study variant pathogenicity.
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Affiliation(s)
- Andrea Accogli
- Division of Medical Genetics, Department of Specialized Medicine, Montreal Children's Hospital, McGill University Health Centre (MUHC), Montreal, Canada; Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Sheng-Jia Lin
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | | | - Sung-Hoon Kim
- Goodman Cancer Institute, McGill University, Montreal, Canada; Department of Biochemistry, McGill University, Montreal, Canada
| | - Kevin Huang
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Clarissa Rocca
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Megan Landsverk
- University of South Dakota Sanford School of Medicine Sioux Falls, SD; Sanford Research, Pediatrics and Rare Diseases Group, Sioux Falls, SD
| | - Maha S Zaki
- Human Genetics and Genome Research Institute, Clinical Genetics Department, National Research Centre, Cairo, Egypt
| | - Almundher Al-Maawali
- Department of Genetics, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman; Genetic and Developmental Medicine Clinic, Sultan Qaboos University Hospital, Muscat, Oman
| | | | - Khalid Al-Thihli
- Department of Genetics, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman; Genetic and Developmental Medicine Clinic, Sultan Qaboos University Hospital, Muscat, Oman
| | - G Bradly Schaefer
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR
| | - Monica Davis
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR
| | - Davide Tonduti
- Unit of Pediatric Neurology, COALA (Center for Diagnosis and Treatment of Leukodystrophies), V. Buzzi Children's Hospital, Milan, Italy; Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Chiara Doneda
- Pediatric Radiology and Neuroradiology Department, Children's Hospital Vittore Buzzi, Milan, Italy
| | - Lara M Marten
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Germany
| | - Chris Mühlhausen
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Germany
| | - Maria Gomez
- Centro de Obsetricia y Ginecologia & Centro Medico Moderno, Santo Domingo, Dominican Republic
| | - Eleonora Lamantea
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Rafael Mena
- Division of Neonatology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH; Centro de Obsetricia y Ginecologia, Santo Domingo, Dominican Republic
| | - Mathilde Nizon
- Service de Génétique Médicale, CHU de Nantes, Nantes Université, Nantes, France; Nantes Université, CNRS, INSERM, l'Institut du Thorax, Nantes, France
| | - Vincent Procaccio
- University of Angers, MitoLab Team, Unité MitoVasc, UMR CNRS 6015, INSERM U1083, SFR ICAT, Angers, France; Department of Genetics, CHU Angers, Angers, France
| | | | | | | | - Heidi L Schulz
- Human Genetic center Tübingen, Baden-Württemberg, Germany
| | - Julia Mohr
- Human Genetic center Tübingen, Baden-Württemberg, Germany
| | - Saskia Biskup
- Human Genetic center Tübingen, Baden-Württemberg, Germany; CeGaT GmbH, Germany
| | - Mariana Amina Loos
- Department of Neurology, Hospital de Pediatría Juan P. Garrahan, Buenos Aires, Argentina
| | - Hilda Verónica Aráoz
- Genomics Laboratory, Hospital de Pediatría Juan P. Garrahan, Buenos Aires, Argentina
| | - Vincenzo Salpietro
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom; Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Laura Davis Keppen
- University of South Dakota Sanford School of Medicine Sioux Falls, SD; Sanford Research, Pediatrics and Rare Diseases Group, Sioux Falls, SD
| | - Manali Chitre
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
| | - Cassidy Petree
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Lucy Raymond
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
| | - Julie Vogt
- West Midlands Regional Genetics Service, Birmingham Women and Children's Hospital NHS Foundation Trust, Birmingham, United Kingdom
| | - Lindsey B Sawyer
- Children's Hospital of the King's Daughters, Norfolk, Virginia, VA
| | - Alice A Basinger
- Children's Hospital of the King's Daughters, Norfolk, Virginia, VA
| | - Signe Vandal Pedersen
- Department of Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Toni S Pearson
- Department of Neurology, Washington University School of Medicine, St. Louis, MO
| | - Dorothy K Grange
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO; Center for the Investigation of Membrane Excitability Diseases (CIMED), St. Louis, MO
| | | | - Paige McDunnah
- Division of Medical Genetics, Nemours/A I duPont Hospital for Children, Wilmington, DE
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Benjamin Cognè
- Service de Génétique Médicale, CHU de Nantes, Nantes Université, Nantes, France; Nantes Université, CNRS, INSERM, l'Institut du Thorax, Nantes, France
| | - Bertrand Isidor
- Service de Génétique Médicale, CHU de Nantes, Nantes Université, Nantes, France
| | - Andreas Hahn
- Department of Child Neurology, University Hospital, Gießen, Germany
| | - Karen W Gripp
- Division of Medical Genetics, Nemours/A I duPont Hospital for Children, Wilmington, DE
| | - Seyed Mehdi Jafarnejad
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, United Kingdom
| | - Elsebet Østergaard
- Department of Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Carlos E Prada
- Division of Genetics, Genomics, and Metabolism, Ann & Robert Lurie Children's Hospital of Chicago, Chicago; Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago; Fundacion Cardiovascular de Colombia, Floridablanca, Colombia
| | - Daniele Ghezzi
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy; Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | | | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom; NHS Highly Specialized Service for Rare Mitochondrial Disorders of Adults and Children, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Nahum Sonenberg
- Goodman Cancer Institute, McGill University, Montreal, Canada; Department of Biochemistry, McGill University, Montreal, Canada
| | - Henry Houlden
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Marie Sissler
- ARNA - UMR5320 CNRS - U1212 INSERM, Université de Bordeaux, IECB, Pessac, France
| | - Gaurav K Varshney
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK.
| | - Reza Maroofian
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom.
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Li L, Zeng P, Yu L, Yang J, Man J, Zhou L, Zhao L. Salinomycin sodium exerts anti diffuse large B-cell lymphoma activity through inhibition of LRP6-mediated Wnt/β-catenin and mTORC1 signaling. Leuk Lymphoma 2023:1-10. [PMID: 37092573 DOI: 10.1080/10428194.2023.2202291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Low-density lipoprotein receptor-related protein-6 (LRP6) is overexpressed in various cancers. The small molecule salinomycin sodium inhibits LRP6. We observed a higher proportion of subjects with non-germinal center B (non-GCB) subtypes having high LRP6 expression than those with GCB subtypes by immunohistochemistry. The PCR and Western blot assays demonstrated increased LRP6 expression in non-GCB subtype cells. In addition, CCK-8 assays and transwell cell migration assays revealed that salinomycin sodium exhibited dose- and time-dependent inhibition of proliferation and migration in non-GCB subtype cells. Furthermore, Western blot assays showed that salinomycin sodium decreased the expression of Bcl2, while increasing the expression of Bax. Additionally, salinomycin sodium suppressed LRP6 expression, blocked LRP6 phosphorylation, and inhibited the Wnt/β-catenin and mTORC1 signaling pathways. Our results suggest that LRP6 is highly expressed in non-GCB subtype. Furthermore, salinomycin sodium inhibited LRP6 expression and the Wnt/β-catenin and mTORC1 signaling in non-GCB subtype cells, and displayed potent anticancer activity.
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Affiliation(s)
- Liangliang Li
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu, P.R. China
- Department of Hematology, Lanzhou University Second Hospital, Lanzhou, Gansu, P.R. China
| | - Pengyun Zeng
- Department of Hematology, Lanzhou University Second Hospital, Lanzhou, Gansu, P.R. China
| | - Lili Yu
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu, P.R. China
- Department of Medical Oncology, Lanzhou University Second Hospital, Lanzhou, Gansu, P.R. China
| | - Jincai Yang
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu, P.R. China
| | - Jiancheng Man
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu, P.R. China
| | - Lanxia Zhou
- Central Laboratory, The First Hospital of Lanzhou University, Lanzhou, Gansu, P.R. China
- Gansu Key Laboratory of Genetic Study of Hematopathy, Lanzhou, Gansu, P.R. China
| | - Li Zhao
- Central Laboratory, The First Hospital of Lanzhou University, Lanzhou, Gansu, P.R. China
- Gansu Key Laboratory of Genetic Study of Hematopathy, Lanzhou, Gansu, P.R. China
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Chen WJ, Huang SY, Chen YW, Liu YF, Huang RFS. Dietary Folate Deficiency Promotes Lactate Metabolic Disorders to Sensitize Lung Cancer Metastasis through MTOR-Signaling-Mediated Druggable Oncotargets. Nutrients 2023; 15:nu15061514. [PMID: 36986244 PMCID: PMC10052195 DOI: 10.3390/nu15061514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/17/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
Lactate metabolism plays a pivotal role in cancers but is often overlooked in lung cancer (LC). Folate deficiency has been linked to lung cancer development, but its impact on lactate metabolism and cancer malignancy is unclear. To investigate this, mice were fed either a folate-deficient (FD) or control diet and intrapleurally implanted with lung cancer cells pre-exposed to FD growth medium. Results showed that FD promoted lactate over-production and the formation of tumor oncospheroids (LCSs) with increased metastatic, migration, and invasion potential. Mice implanted with these cells and fed an FD diet developed hyperlactatemia in blood and lungs. This coincided with increased expression of hexokinase 2 (HK2), lactate dehydrogenase (LDH), and decreased expression of pyruvate dehydrogenase (PDH). Pre-treatment of the FD-LCS-implanted mice with the mTORC1 inhibitor, rapamycin, and the anti-metabolic drug metformin abolished FD/LCS-activated mTORC1 and its targets including HIF1α, HK2, LDH, and monocarboxylate transporters (MCT1 and MCT4), which coincided with the reduction in lactate disorders and prevention of LC metastasis. The findings suggest that dietary FD promotes lactate metabolic disorders that sensitize lung cancer metastasis through mTOR-signaling-mediated targets.
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Affiliation(s)
- Wan-Jing Chen
- Program in Nutrition and Food Science, Fu Jen Catholic University, New Taipei City 242, Taiwan
| | - Su-Yu Huang
- Department of Nutritional Science, Fu Jen Catholic University, New Taipei City 242, Taiwan
| | - Yi-Wen Chen
- Department of Nutritional Science, Fu Jen Catholic University, New Taipei City 242, Taiwan
| | - Yi-Fang Liu
- Program in Nutrition and Food Science, Fu Jen Catholic University, New Taipei City 242, Taiwan
- Department of Nutritional Science, Fu Jen Catholic University, New Taipei City 242, Taiwan
| | - Rwei-Fen S Huang
- Program in Nutrition and Food Science, Fu Jen Catholic University, New Taipei City 242, Taiwan
- Department of Nutritional Science, Fu Jen Catholic University, New Taipei City 242, Taiwan
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Fushimi S, Nohno T, Katsuyama H. Chronic Stress Induces Type 2b Skeletal Muscle Atrophy via the Inhibition of mTORC1 Signaling in Mice. Med Sci (Basel) 2023; 11:medsci11010019. [PMID: 36810486 PMCID: PMC9944114 DOI: 10.3390/medsci11010019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 02/12/2023] Open
Abstract
Chronic stress induces psychological and physiological changes that may have negative sequelae for health and well-being. In this study, the skeletal muscles of male C57BL/6 mice subjected to repetitive water-immersion restraint stress to model chronic stress were examined. In chronically stressed mice, serum corticosterone levels significantly increased, whereas thymus volume and bone mineral density decreased. Further, body weight, skeletal muscle mass, and grip strength were significantly decreased. Histochemical analysis of the soleus muscles revealed a significant decrease in the cross-sectional area of type 2b muscle fibers. Although type 2a fibers also tended to decrease, chronic stress had no impact on type 1 muscle fibers. Chronic stress increased the expression of REDD1, FoxO1, FoxO3, KLF15, Atrogin1, and FKBP5, but did not affect the expression of myostatin or myogenin. In contrast, chronic stress resulted in a decrease in p-S6 and p-4E-BP1 levels in the soleus muscle. Taken together, these results indicate that chronic stress promotes muscle atrophy by inhibiting mammalian targets of rapamycin complex 1 activity due to the upregulation of its inhibitor, REDD1.
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Hu J, Gao X, Chen L, Kan Y, Du Z, Xin S, Ji W, Yu Q, Cao L. Identification of two rare NPRL3 variants in two Chinese families with familial focal epilepsy with variable foci 3: NGS analysis with literature review. Front Genet 2023; 13:1054567. [PMID: 36685832 PMCID: PMC9852884 DOI: 10.3389/fgene.2022.1054567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 12/19/2022] [Indexed: 01/07/2023] Open
Abstract
Background: The GAP Activity Towards Rags 1 (GATOR1) complex, which includes DEPDC5, NPRL2, and NPRL3, plays a key role in epilepsy. It has been reported that focal epilepsy is associated with mutations in the NPRL3 gene in some cases. We report two rare mutations in the NPRL3 gene in two unrelated Chinese families with focal epilepsy in this study. Methods: The proband and her brother in family E1 first experienced seizures at 1.5 and 6 years of age, respectively. Despite resection of epileptogenic foci, she still suffered recurrent seizures. The first seizure of a 20-year-old male proband in family E2 occurred when he was 2 years old. To identify pathogenic variants in these families, whole-exome sequencing (WES) was performed on genomic DNA from peripheral blood. Results: In family E1, the trio-WES analysis of the proband and her brother without apparent structural brain abnormalities identified a heterozygous variant in the NPRL3 gene (c.954C>A, p.Y318*, NM_001077350.3). In family E2, the proband carried a heterozygous NPRL3 mutation (c.1545-1G>C, NM_001077350.3). Surprisingly, the mothers of the two probands each carried the variants, but neither had an attack. Bioinformatics analysis predicted that the mutation (c.954C>A) was in the highly conserved amino acid residues of NPRL3, which affected the α-helix of NPRL3 protein, leading to a truncated protein. The splice variant (c.1545-1G>C) resulted in the loss of the last exon of the NPRL3 gene. Conclusion: The results of this study provide a foundation for diagnosing NPRL3-related epilepsy by enriching their genotypes and phenotypes and help us identify the genetic etiologies of epilepsy in these two families.
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Affiliation(s)
- Junji Hu
- Department of Neurology, Zibo Changguo Hospital, Zibo, Shandong, China
| | - Xueping Gao
- Yinfeng Gene Technology Co, Ltd, Jinan, Shandong, China
| | - Longchang Chen
- Department of Neurology, Zibo Changguo Hospital, Zibo, Shandong, China
| | - Yuling Kan
- Central Laboratory, Binzhou People’s Hospital, Binzhou, Shandong, China
| | - Zhaoli Du
- Yinfeng Gene Technology Co, Ltd, Jinan, Shandong, China
| | | | - Wenkai Ji
- Yinfeng Gene Technology Co, Ltd, Jinan, Shandong, China
| | - Qiang Yu
- Yinfeng Gene Technology Co, Ltd, Jinan, Shandong, China
| | - Lili Cao
- Department of Neurology, Cheeloo College of Medicine, Qilu Hospital, Shandong University, Jinan, China,*Correspondence: Lili Cao,
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Orr HT. Cholecystokinin Activation of Cholecystokinin 1 Receptors: a Purkinje Cell Neuroprotective Pathway. Cerebellum 2022:10.1007/s12311-022-01428-x. [PMID: 35733029 DOI: 10.1007/s12311-022-01428-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
This is a summary of the virtual presentation given at the 2021 meeting of the Society for Research on the Cerebellum and Ataxias, https://www.meetings.be/SRCA2021/ , where the therapeutic potential of the CCK-CCK1R pathway for treating diseases involving Purkinje cell degeneration was presented. Spinocerebellar ataxia type 1 (SCA1) is one of a group of almost 50 genetic diseases characterized by the degeneration of cerebellar Purkinje cells. The SCA1 Pcp2-ATXN1[30Q]D776 mouse model displays ataxia, i.e. Purkinje cell dysfunction, but lacks progressive Purkinje cell degeneration. RNA-seq revealed increased expression of cholecystokinin (CCK) in cerebella of Pcp2-ATXN1[30Q]D776 mice. Importantly, the absence of Cck1 receptor (CCK1R) in Pcp2-ATXN1[30Q]D776 mice conferred a progressive degenerative disease with Purkinje cell loss. Administration of a CCK1R agonist to Pcp2-AXTN1[82Q] mice reduced Purkinje cell pathology and associated deficits in motor performance. In addition, administration of the CCK1R agonist improved motor performance of Pcp2-ATXN2[127Q] SCA2 mice. Furthermore, CCK1R activation corrected mTORC1 signaling and improved the expression of calbindin in the cerebella of AXTN1[82Q] and ATXN2[127Q] mice. These results support the Cck-Cck1R pathway is a potential therapeutic target for the treatment of diseases involving Purkinje neuron degeneration.
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Affiliation(s)
- Harry T Orr
- Institute of Translational Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA.
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, 55455, USA.
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10
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Gao F, Liu A, Qi X, Wang M, Chen X, Wei S, Gao S, Sun Y, Sun P, Li X, Sun W, Li J, Liu Q. Ppp4r3a deficiency leads to depression-like behaviors in mice by modulating the synthesis of synaptic proteins. Dis Model Mech 2022; 15:dmm049374. [PMID: 35314861 PMCID: PMC9150120 DOI: 10.1242/dmm.049374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 03/15/2022] [Indexed: 11/24/2022] Open
Abstract
Chronic stress is one of the main risk factors for the onset of major depressive disorder. Chronic unpredictable mild stress results in reduced expression of synaptic proteins and depression-like behaviors in rodent models. However, the upstream molecule that senses the demand for synaptic proteins and initiates their synthesis under chronic stress remains unknown. In this study, chronic unpredictable mild stress reduced the expression of PPP4R3A in the prefrontal cortex and hippocampus in mice. Selective knockout of Ppp4r3a in the cortex and hippocampus mimicked the depression- and anxiety-like behavioral effects of chronic stress in mice. Notably, Ppp4r3a deficiency led to downregulated mTORC1 signaling, which resulted in reduced synthesis of synaptic proteins and impaired synaptic functions. By contrast, overexpression of Ppp4r3a in the cortex and hippocampus protected against behavioral and synaptic deficits induced by chronic stress in a PPP4R3A-mTORC1-dependent manner. Rapamycin treatment of Ppp4r3a-overexpressing neurons blocked the regulatory effect of Ppp4r3a on the synthesis of synaptic proteins by directly inhibiting mTORC1. Overall, our results reveal a regulatory role of Ppp4r3a in driving synaptic protein synthesis in chronic stress.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Qiji Liu
- Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Medical Genetics, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
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11
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Kútna V, O'Leary VB, Hoschl C, Ovsepian SV. Cerebellar demyelination and neurodegeneration associated with mTORC1 hyperactivity may contribute to the developmental onset of autism-like neurobehavioral phenotype in a rat model. Autism Res 2022; 15:791-805. [PMID: 35178882 DOI: 10.1002/aur.2688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 01/14/2022] [Accepted: 02/06/2022] [Indexed: 02/06/2023]
Abstract
The cerebellum hosts more than half of all neurons of the human brain, with their organized activity playing a key role in coordinating motor functions. Cerebellar activity has also been implicated in the control of speech, communication, and social behavior, which are compromised in autism spectrum disorders (ASD). Despite major research advances, there is a shortage of mechanistic data relating cellular and molecular changes in the cerebellum to autistic behavior. We studied the impact of tuberous sclerosis complex 2 haploinsufficiency (Tsc2+/-) with downstream mTORC1 hyperactivity on cerebellar morphology and cellular organization in 1, 9, and 18 m.o. Eker rats, to determine possible structural correlates of an autism-like behavioural phenotype in this model. We report a greater developmental expansion of the cerebellar vermis, owing to enlarged white matter and thickened molecular layer. Histochemical and immunofluorescence data suggest age-related demyelination of central tract of the vermis, as evident from reduced level of myelin-basic protein in the arbora vitae. We also observed a higher number of astrocytes in Tsc2+/- rats of older age while the number of Purkinje cells (PCs) in these animals was lower than in wild-type controls. Unlike astrocytes and PCs, Bergmann glia remained unaltered at all ages in both genotypes, while the number of microglia was higher in Tsc2+/- rats of older age. The convergent evidence for a variety of age-dependent cellular changes in the cerebellum of rats associated with mTORC1 hyperactivity, thus, predicts an array of functional impairments, which may contribute to the developmental onset of an autism-like behavioral phenotype in this model. LAY SUMMARY: This study elucidates the impact of constitutive mTORC1 hyperactivity on cerebellar morphology and cellular organization in a rat model of autism and epilepsy. It describes age-dependent degeneration of Purkinje neurons, with demyelination of central tract as well as activation of microglia, and discusses the implications of these changes for neuro-behavioral phenotypes. The described changes provide new indications for the putative mechanisms underlying cerebellar impairments with their age-related onset, which may contribute to the pathobiology of autism, epilepsy, and related disorders.
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Affiliation(s)
- Viera Kútna
- Department of Experimental Neurobiology, National Institute of Mental Health, Klecany, Czech Republic
| | - Valerie Bríd O'Leary
- Department of Medical Genetics, Third Faculty of Medicine, Charles University, Prague 10, Czech Republic
| | - Cyril Hoschl
- Department of Experimental Neurobiology, National Institute of Mental Health, Klecany, Czech Republic.,Department of Psychiatry and Medical Psychology, Third Faculty of Medicine, Charles University, Prague 10, Czech Republic
| | - Saak V Ovsepian
- Faculty of Engineering and Science, University of Greenwich London, Chatham Maritime, Kent, ME4 4TB, United Kingdom
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12
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Wozniak EAL, Chen Z, Paul S, Yang P, Figueroa KP, Friedrich J, Tschumperlin T, Berken M, Ingram M, Henzler C, Pulst SM, Orr HT. Cholecystokinin 1 receptor activation restores normal mTORC1 signaling and is protective to Purkinje cells of SCA mice. Cell Rep 2021; 37:109831. [PMID: 34644575 PMCID: PMC8916043 DOI: 10.1016/j.celrep.2021.109831] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 07/23/2021] [Accepted: 09/22/2021] [Indexed: 12/20/2022] Open
Abstract
Spinocerebellar ataxias (SCAs) are a group of genetic diseases characterized by progressive ataxia and neurodegeneration, often in cerebellar Purkinje neurons. A SCA1 mouse model, Pcp2-ATXN1[30Q]D776, has severe ataxia in absence of progressive Purkinje neuron degeneration and death. Previous RNA-seq analyses identify cerebellar upregulation of the peptide hormone cholecystokinin (Cck) in Pcp2-ATXN1[30Q]D776 mice. Importantly, absence of Cck1 receptor (Cck1R) in Pcp2-ATXN1[30Q]D776 mice confers a progressive disease with Purkinje neuron death. Administration of a Cck1R agonist, A71623, to Pcp2-ATXN1[30Q]D776;Cck-/- and Pcp2-AXTN1[82Q] mice dampens Purkinje neuron pathology and associated deficits in motor performance. In addition, A71623 administration improves motor performance of Pcp2-ATXN2[127Q] SCA2 mice. Moreover, the Cck1R agonist A71623 corrects mTORC1 signaling and improves expression of calbindin in cerebella of AXTN1[82Q] and ATXN2[127Q] mice. These results indicate that manipulation of the Cck-Cck1R pathway is a potential therapeutic target for treatment of diseases involving Purkinje neuron degeneration.
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Affiliation(s)
- Emily A L Wozniak
- Institute of Translational Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA; Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Zhao Chen
- Institute of Translational Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA; Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Sharan Paul
- Department of Neurology, University of Utah, Salt Lake City, UT 84112, USA
| | - Praseuth Yang
- Institute of Translational Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Karla P Figueroa
- Department of Neurology, University of Utah, Salt Lake City, UT 84112, USA
| | - Jill Friedrich
- Institute of Translational Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Tyler Tschumperlin
- Institute of Translational Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Michael Berken
- Institute of Translational Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Melissa Ingram
- Institute of Translational Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA; Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Christine Henzler
- RISS Bioinformatics, Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455, USA
| | - Stefan M Pulst
- Department of Neurology, University of Utah, Salt Lake City, UT 84112, USA; Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA.
| | - Harry T Orr
- Institute of Translational Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA.
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13
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Wei S, Dai M, Zhang C, Teng K, Wang F, Li H, Sun W, Feng Z, Kang T, Guan X, Xu R, Cai M, Xie D. KIF2C: a novel link between Wnt/β-catenin and mTORC1 signaling in the pathogenesis of hepatocellular carcinoma. Protein Cell 2021; 12:788-809. [PMID: 32748349 PMCID: PMC8464548 DOI: 10.1007/s13238-020-00766-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Accepted: 06/28/2020] [Indexed: 12/17/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is the most common primary liver malignancy and is the fourth-leading cause of cancer-related deaths worldwide. HCC is refractory to many standard cancer treatments and the prognosis is often poor, highlighting a pressing need to identify biomarkers of aggressiveness and potential targets for future treatments. Kinesin family member 2C (KIF2C) is reported to be highly expressed in several human tumors. Nevertheless, the molecular mechanisms underlying the role of KIF2C in tumor development and progression have not been investigated. In this study, we found that KIF2C expression was significantly upregulated in HCC, and that KIF2C up-regulation was associated with a poor prognosis. Utilizing both gain and loss of function assays, we showed that KIF2C promoted HCC cell proliferation, migration, invasion, and metastasis both in vitro and in vivo. Mechanistically, we identified TBC1D7 as a binding partner of KIF2C, and this interaction disrupts the formation of the TSC complex, resulting in the enhancement of mammalian target of rapamycin complex1 (mTORC1) signal transduction. Additionally, we found that KIF2C is a direct target of the Wnt/β-catenin pathway, and acts as a key factor in mediating the crosstalk between Wnt/β-catenin and mTORC1 signaling. Thus, the results of our study establish a link between Wnt/β-catenin and mTORC1 signaling, which highlights the potential of KIF2C as a therapeutic target for the treatment of HCC.
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Affiliation(s)
- Shi Wei
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Miaomiao Dai
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Chi Zhang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Kai Teng
- Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, 250200, China
| | - Fengwei Wang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Hongbo Li
- Department of Musculoskeletal Oncology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510080, China
| | - Weipeng Sun
- Department of Anorectal Surgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 510370, China
| | - Zihao Feng
- Department of Urology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510080, China
| | - Tiebang Kang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Xinyuan Guan
- Department of Clinical Oncology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Ruihua Xu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Muyan Cai
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China.
- Department of Pathology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China.
| | - Dan Xie
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China.
- Department of Pathology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China.
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14
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Fairweather SJ, Okada S, Gauthier-Coles G, Javed K, Bröer A, Bröer S. A GC-MS/Single-Cell Method to Evaluate Membrane Transporter Substrate Specificity and Signaling. Front Mol Biosci 2021; 8:646574. [PMID: 33928121 PMCID: PMC8076599 DOI: 10.3389/fmolb.2021.646574] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Accepted: 02/17/2021] [Indexed: 12/18/2022] Open
Abstract
Amino acid transporters play a vital role in metabolism and nutrient signaling pathways. Typically, transport activity is investigated using single substrates and competing amounts of other amino acids. We used GC-MS and LC-MS for metabolic screening of Xenopus laevis oocytes expressing various human amino acid transporters incubated in complex media to establish their comprehensive substrate profiles. For most transporters, amino acid selectivity matched reported substrate profiles. However, we could not detect substantial accumulation of cationic amino acids by SNAT4 and ATB0,+ in contrast to previous reports. In addition, comparative substrate profiles of two related sodium neutral amino acid transporters known as SNAT1 and SNAT2, revealed the latter as a significant leucine accumulator. As a consequence, SNAT2, but not SNAT1, was shown to be an effective activator of the eukaryotic cellular growth regulator mTORC1. We propose, that metabolomic profiling of membrane transporters in Xe nopus laevis oocytes can be used to test their substrate specificity and role in intracellular signaling pathways.
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Affiliation(s)
- Stephen J. Fairweather
- Research School of Biology, Australian National University, Canberra, ACT, Australia
- Research School of Chemistry, Australian National University, Canberra, ACT, Australia
| | - Shoko Okada
- Commonwealth Scientific and Industrial Research Institute (CSIRO) Land and Water, Canberra, ACT, Australia
| | | | - Kiran Javed
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Angelika Bröer
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Stefan Bröer
- Research School of Biology, Australian National University, Canberra, ACT, Australia
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15
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Liu Z, Wang X, Shi Z, Xu J, Lin J, Li D, Zhang X, Li Y, Zhao Q, Tao L, Diao A. Cetrimonium bromide promotes the clearance of lipids by activating the TFEB-mediated autophagosome-lysosome pathway in hepatic cells. Biochem Cell Biol 2021; 99:519-526. [PMID: 33560918 DOI: 10.1139/bcb-2020-0570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Autophagy plays a key role in the metabolism of macromolecules via the degradative abilities of the lysosome. Transcription factor EB (TFEB) regulates autophagosome biogenesis and lysosome function, and promoting TFEB activity has emerged as a potential strategy for the treatment of metabolic disorders. Herein, we report that cetrimonium bromide (CTAB; a quaternary ammonium compound) promotes autophagy and lysosomal biogenesis by inducing the nuclear translocation of TFEB in hepatic cells. Knockdown of TFEB mediated by short hairpin RNA inhibits CTAB-induced autophagy and lysosomal biogenesis. Mechanistically, CTAB treatment inhibits the Akt-mTORC1 signaling pathway. Moreover, CTAB treatment significantly increases lipid metabolism in both palmitate- and oleate-treated HepG2 cells, and this increase was attenuated by knockdown of TFEB. Collectively, our results indicate that CTAB activates the autophagosome-lysosome pathway via inducing the nuclear translocation of TFEB by inhibiting the mTORC1 signaling pathway. These results add to the collective understanding of TFEB function and provide new insights into CTAB-mediated lipid metabolism.
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Affiliation(s)
- Zhenxing Liu
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China.,School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China
| | - Xu Wang
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China.,School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China
| | - Zhichen Shi
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China.,School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China
| | - Junting Xu
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China.,School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China
| | - Jieru Lin
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China.,School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China
| | - Dianlong Li
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China.,School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China
| | - Xinpeng Zhang
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China.,School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China
| | - Yuyin Li
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China.,School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China
| | - Qing Zhao
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China.,School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China
| | - Li Tao
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China.,School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China
| | - Aipo Diao
- School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China.,School of Biotechnology, Tianjin University of Science and Technology, Key Lab of Industrial Fermentation Microbiology of the Ministry of Education, State Key Laboratory of Food Nutrition and Safety, Tianjin 300457, China
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16
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Savukaitytė A, Gudoitytė G, Bartnykaitė A, Ugenskienė R, Juozaitytė E. siRNA Knockdown of REDD1 Facilitates Aspirin-Mediated Dephosphorylation of mTORC1 Target 4E-BP1 in MDA-MB-468 Human Breast Cancer Cell Line. Cancer Manag Res 2021; 13:1123-1133. [PMID: 33574709 PMCID: PMC7872862 DOI: 10.2147/cmar.s264414] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 12/11/2020] [Indexed: 12/17/2022] Open
Abstract
Background Mutations within genes encoding components of the PI3K/AKT/mTOR (phosphoinositide 3-kinase/protein kinase B/mechanistic target of rapamycin) signaling axis frequently activate the pathway in breast cancer, making it an attractive therapeutic target. Inhibition of mTORC1 (mechanistic target of rapamycin complex 1) activity upon aspirin treatment has been reported in breast cancer cells harboring PI3KCA (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha) mutation and is considered to account for anticancer action. Methods MDA-MB-468 (harbors mutated PTEN (phosphatase and TENsin homolog)), MCF-7 (PI3KCA-mutated), MDA-MB-231 (no PI3K pathway mutations) cancer cell lines and MCF10A non-cancerous breast epithelial cells were employed for the assessment of modulation of mTORC1 signaling by aspirin. Targeted amplicon-based next-generation sequencing using the Ion Torrent technology was carried out to determine gene expression changes following drug treatment. Western blot was performed to analyze the expression and phosphorylation of proteins. Knockdown by siRNA approach was applied to assess the role of REDD1/DDIT4 (DNA damage-inducible transcript 4) in mTORC1 inhibition by aspirin. Results We show a decline in phosphorylation of mTORC1 downstream substrate 4E-BP1 (eukaryotic translation initiation factor 4E-binding protein 1) in response to treatment with aspirin and its metabolite salicylic acid in MDA-MB-468, MCF-7, MDA-MB-231, and MCF10A cell lines. We further demonstrate a novel molecular response to aspirin in breast cancer cells. Specifically, we found that aspirin and salicylic acid increase the expression of REDD1 protein, that is known for its suppressive function towards mTORC1. Unexpectedly, we observed that siRNA knockdown of REDD1 expression facilitated aspirin-mediated suppression of mTORC1 downstream substrate 4E-BP1 phosphorylation in the MDA-MB-468 cell line. REDD1 downregulation slightly encouraged reduction in 4E-BP1 phosphorylation by aspirin in MCF-7 cells but did not elicit a reproducible effect in the MDA-MB-231 cell line. siRNA knockdown of REDD1 did not affect the expression of phosphorylated form of 4E-BP1 following aspirin treatment in MCF10A non-cancerous breast epithelial cells. Conclusion The current findings suggest that REDD1 downregulation might improve the anticancer activity of aspirin in a subset of breast tumors.
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Affiliation(s)
- Aistė Savukaitytė
- Oncology Research Laboratory, Institute of Oncology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Greta Gudoitytė
- Oncology Research Laboratory, Institute of Oncology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Agnė Bartnykaitė
- Oncology Research Laboratory, Institute of Oncology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Rasa Ugenskienė
- Oncology Research Laboratory, Institute of Oncology, Lithuanian University of Health Sciences, Kaunas, Lithuania.,Institute of Biology Systems and Genetic Research, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Elona Juozaitytė
- Department of Oncology and Hematology, Hospital of Lithuanian University of Health Sciences Kaunas Clinics, Kaunas, Lithuania
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17
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Yu J, Wu C, Wu Q, Huang J, Fu W, Xie X, Li W, Tang W, Xu C, Jin G. PCYT1A suppresses proliferation and migration via inhibiting mTORC1 pathway in lung adenocarcinoma. Biochem Biophys Res Commun 2020; 529:353-361. [PMID: 32703435 DOI: 10.1016/j.bbrc.2020.05.164] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 05/22/2020] [Indexed: 12/26/2022]
Abstract
Lung cancer is one of most common malignant cancer worldwide. It is emerging that PCYT1A, a rate-limiting enzyme required for the biosynthesis of phosphatidylcholine, is associated with cancer progression. However, the biological functions and underlying molecular mechanisms of PCYT1A in lung adenocarcinoma is still unknown. Here we found that PCYT1A suppressed lung adenocarcinoma cancer cell proliferation and migration. Mechanically, PCYT1A served as a novel negative regulator of mTORC1 signaling. PCYT1A knockdown enhanced the malignant proliferation and migration of lung adenocarcinoma cells by activating mTORC1. The promoting effects of PCYT1A silencing on cell proliferation and migration could be abolished when mTORC1 signaling was inhibited by rapamycin or RAPTOR depletion. Importantly, PCYT1A high expression predicted longer survival of lung cancer patients. The expression of PCYT1A was also negatively correlated with mTORC1 activation in the clinical lung cancer samples. We therefore reveal that PCYT1A suppresses proliferation and migration by inhibiting the mTORC1 signaling pathway in lung adenocarcinoma. PCYT1A shows as a potential promising biomarker in lung adenocarcinoma.
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Affiliation(s)
- Jing Yu
- Department of Oncology, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China; Institute of Pathology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University (Army Medical University), And Key Laboratory of Tumor Immunopathology, Ministry of Education of China, Chongqing, China
| | - Changtao Wu
- Institute of Pathology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University (Army Medical University), And Key Laboratory of Tumor Immunopathology, Ministry of Education of China, Chongqing, China; Department of Colorectal and Anal Surgery, The First Affiliated Hospital, Guangxi Medical University, Nanning, 530021, China
| | - Qi Wu
- Institute of Pathology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University (Army Medical University), And Key Laboratory of Tumor Immunopathology, Ministry of Education of China, Chongqing, China
| | - Jiafeng Huang
- Institute of Pathology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University (Army Medical University), And Key Laboratory of Tumor Immunopathology, Ministry of Education of China, Chongqing, China
| | - Wenjuan Fu
- Institute of Pathology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University (Army Medical University), And Key Laboratory of Tumor Immunopathology, Ministry of Education of China, Chongqing, China
| | - Xuemei Xie
- Department of Pathology, The Affiliated Hospital of North Sichuan Medical College, Nanchong, 637100, China
| | - Wen Li
- Integrative Cancer Center & Cancer Clinical Research Center, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine University of Electronic Science and Technology of China, Chengdu, 610047, China
| | - Weizhong Tang
- Department of Gastrointestinal Surgery, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, 530021, China
| | - Chuan Xu
- Department of Oncology, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China; Integrative Cancer Center & Cancer Clinical Research Center, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine University of Electronic Science and Technology of China, Chengdu, 610047, China.
| | - Guoxiang Jin
- Institute of Pathology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University (Army Medical University), And Key Laboratory of Tumor Immunopathology, Ministry of Education of China, Chongqing, China.
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18
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Marchi S, Retta SF, Pinton P. Detection of p62/SQSTM1 Aggregates in Cellular Models of CCM Disease by Immunofluorescence. Methods Mol Biol 2020; 2152:417-426. [PMID: 32524569 DOI: 10.1007/978-1-0716-0640-7_30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Cerebral cavernous malformations (CCM) is a familial or sporadic rare disorder that is characterized by capillary vascular lesions with a mulberry-like appearance on MRI scans. Three distinct genes have been associated to CCM disease, known as CCM1/KRIT1, CCM2/MGC4607, and CCM3/PDCD10. Loss-of-functions mutations on these genes lead to deregulation in multiple signaling pathways, thereby resulting in disturbed vessel organization and function. Insufficient autophagy has been observed upon downregulation of all three CCM genes, both in cells and human patient tissues, revealed as aberrant accumulation of the autophagy receptor p62/SQSTM1. The autophagic process is conceived as an adaptive response to stress and is essential for the maintenance of cellular homeostasis. The aim of this review is to briefly summarize the current knowledge on the role of autophagy in CCM disease and to furnish a detailed protocol for detecting and measuring p62/SQSTM1 cytoplasmic aggregates through immunofluorescence technique.
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Affiliation(s)
- Saverio Marchi
- Department of Clinical and Molecular Sciences, Marche Polytechnic University, Ancona, Italy.
| | - Saverio Francesco Retta
- Department of Clinical and Biological Science, School of Medicine and Surgery, University of Torino, Orbassano (Torino), Torino, Italy
- CCM Italia Research Network, Torino, Italy
| | - Paolo Pinton
- Department of Medical Sciences, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
- Maria Cecilia Hospital, GVM Care & Research, Cotignola, Ravenna, Italy
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19
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Peng Q, Chen B, Wang H, Zhu Y, Wu J, Luo Y, Zuo G, Luo J, Zhou L, Shi Q, Weng Y, Huang A, He TC, Fan J. Bone morphogenetic protein 4 (BMP4) alleviates hepatic steatosis by increasing hepatic lipid turnover and inhibiting the mTORC1 signaling axis in hepatocytes. Aging (Albany NY) 2019; 11:11520-11540. [PMID: 31831718 PMCID: PMC6932923 DOI: 10.18632/aging.102552] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 11/19/2019] [Indexed: 02/06/2023]
Abstract
Liver has numerous critical metabolic functions including lipid metabolism, which is usually dysregulated in obesity, the metabolic syndrome, and non-alcoholic fatty liver disease (NAFLD). Increasing evidence indicates bone morphogenetic proteins (BMPs) play an important role in adipogenesis and thermogenic balance in adipogenic progenitors and adipose tissue. However, the direct impact of BMPs on hepatic steatosis and possible association with NAFLD are poorly understood. Here, we found that BMP4 was up-regulated in oleic acid-induced steatosis and during the development of high fat diet (HFD)-induced NAFLD. Exogenous BMP4 reduced lipid accumulation and up-regulated the genes involved in lipid synthesis, storage and breakdown in hepatocytes. Exogenous BMP4 inhibited hepatic steatosis, reduced serum triglyceride levels and body weight, and alleviated progression of NAFLD in vivo. Mechanistically, BMP4 overexpression in hepatocytes down-regulated most components of the mTORC1 signaling axis. Collectively, these findings strongly suggest that BMP4 may play an essential role in regulating hepatic lipid metabolism and the molecular pathogenesis of NAFLD. Manipulating BMP4 and/or mTORC1 signaling axis may lead to the development of novel therapeutics for obesity, metabolic syndrome, and NAFLD.
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Affiliation(s)
- Qi Peng
- Ministry of Education Key Laboratory of Diagnostic Medicine, and School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Bin Chen
- Ministry of Education Key Laboratory of Diagnostic Medicine, and School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Hao Wang
- Ministry of Education Key Laboratory of Diagnostic Medicine, and School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Ying Zhu
- Ministry of Education Key Laboratory of Diagnostic Medicine, and School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Jinghong Wu
- Ministry of Education Key Laboratory of Diagnostic Medicine, and School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Yetao Luo
- Clinical Epidemiology and Biostatistics Department, Department of Pediatric Research Institute, Children’s Hospital of Chongqing Medical University, Chongqing 400014, China
| | - Guowei Zuo
- Ministry of Education Key Laboratory of Diagnostic Medicine, and School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Jinyong Luo
- Ministry of Education Key Laboratory of Diagnostic Medicine, and School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Lan Zhou
- Ministry of Education Key Laboratory of Diagnostic Medicine, and School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Qiong Shi
- Ministry of Education Key Laboratory of Diagnostic Medicine, and School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Yaguang Weng
- Ministry of Education Key Laboratory of Diagnostic Medicine, and School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Ailong Huang
- Key Laboratory of Molecular Biology for Infectious Diseases of The Ministry of Education of China, Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Tong-Chuan He
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Jiaming Fan
- Ministry of Education Key Laboratory of Diagnostic Medicine, and School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
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20
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Williams MM, Elion DL, Rahman B, Hicks DJ, Sanchez V, Cook RS. Therapeutic inhibition of Mcl-1 blocks cell survival in estrogen receptor-positive breast cancers. Oncotarget 2019; 10:5389-5402. [PMID: 31595181 PMCID: PMC6739218 DOI: 10.18632/oncotarget.27070] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 06/14/2019] [Indexed: 12/17/2022] Open
Abstract
Cancers often overexpress anti-apoptotic Bcl-2 proteins for cell death evasion, a recognized hallmark of cancer progression. While estrogen receptor (ER)-α+ breast cancers express high levels of three anti-apoptotic Bcl-2 family members (Bcl-2, Bcl-xL, and Mcl-1), pharmacological inhibition of Bcl-2 and/or Bcl-xL fails to induce cell death in ERα+ breast cancer cell lines, due to rapid and robust Mcl-1 upregulation. The mechanisms of acute Mcl-1 upregulation in response to Bcl-2/Bcl-xL inhibition remain undefined in in ERα+ breast cancers. We report here that blockade of Bcl-2 or Bcl-xL, alone or together, rapidly induced mTOR signaling in ERα+ breast cancer cells, rapidly increasing cap-dependent Mcl-1 translation. Cells treated with a pharmacological inhibitor of cap-dependent translation, or with the mTORC1 inhibitor RAD001/everolimus, displayed reduced protein levels of Mcl-1 under basal conditions, and failed to upregulate Mcl-1 protein expression following treatment with ABT-263, a pharmacological inhibitor of Bcl-2 and Bcl-xL. Although treatment with ABT-263 alone did not sustain apoptosis in tumor cells in culture or in vivo, ABT-263 plus RAD001 increased apoptosis to a greater extent than either agent used alone. Similarly, combined use of the selective Mcl-1 inhibitor VU661013 with ABT-263 resulted in tumor cell apoptosis and diminished tumor growth in vivo. These findings suggest that rapid Mcl-1 translation drives ABT-263 resistance, but can be combated directly using emerging Mcl-1 inhibitors, or indirectly through existing and approved mTOR inhibitors.
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Affiliation(s)
| | - David L Elion
- Program in Cancer Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Bushra Rahman
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Donna J Hicks
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Violeta Sanchez
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Rebecca S Cook
- Program in Cancer Biology, Vanderbilt University, Nashville, TN 37232, USA.,Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville TN 37232, USA.,The Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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21
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Wu R, Dang F, Li P, Wang P, Xu Q, Liu Z, Li Y, Wu Y, Chen Y, Liu Y. The Circadian Protein Period2 Suppresses mTORC1 Activity via Recruiting Tsc1 to mTORC1 Complex. Cell Metab 2019; 29:653-667.e6. [PMID: 30527742 DOI: 10.1016/j.cmet.2018.11.006] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 08/30/2018] [Accepted: 11/11/2018] [Indexed: 12/15/2022]
Abstract
Although emerging evidence indicates an important role of the circadian clock in modulating the diurnal oscillation of mammalian target of rapamycin complex 1 (mTORC1) signaling, the underlying molecular mechanism remains elusive. Here we show that Period2 (Per2), a core clock protein, functions as a scaffold protein to tether tuberous sclerosis complex 1 (Tsc1), Raptor, and mTOR together to specifically suppress the activity of mTORC1 complex. Due to the loss of its inhibition of mTORC1, Per2 deficiency significantly enhances protein synthesis and cell proliferation but reduces autophagy. Furthermore, we find that the glucagon-Creb/Crtc2 signaling cascade induces Per2 expression, which mediates the suppression of mTORC1 in mouse liver during fasting. Our study not only uncovers a novel role of Per2 in regulating the mTORC1 pathway, but also sheds new light on the mechanism of fasting inhibition on mTORC1 in the liver.
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22
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Zeng H, Lu B, Zamponi R, Yang Z, Wetzel K, Loureiro J, Mohammadi S, Beibel M, Bergling S, Reece-Hoyes J, Russ C, Roma G, Tchorz JS, Capodieci P, Cong F. mTORC1 signaling suppresses Wnt/β-catenin signaling through DVL-dependent regulation of Wnt receptor FZD level. Proc Natl Acad Sci U S A 2018; 115:E10362-9. [PMID: 30297426 DOI: 10.1073/pnas.1808575115] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Wnt/β-catenin signaling plays pivotal roles in cell proliferation and tissue homeostasis by maintaining somatic stem cell functions. The mammalian target of rapamycin (mTOR) signaling functions as an integrative rheostat that orchestrates various cellular and metabolic activities that shape tissue homeostasis. Whether these two fundamental signaling pathways couple to exert physiological functions still remains mysterious. Using a genome-wide CRISPR-Cas9 screening, we discover that mTOR complex 1 (mTORC1) signaling suppresses canonical Wnt/β-catenin signaling. Deficiency in tuberous sclerosis complex 1/2 (TSC1/2), core negative regulators of mTORC1 activity, represses Wnt/β-catenin target gene expression, which can be rescued by RAD001. Mechanistically, mTORC1 signaling regulates the cell surface level of Wnt receptor Frizzled (FZD) in a Dishevelled (DVL)-dependent manner by influencing the association of DVL and clathrin AP-2 adaptor. Sustained mTORC1 activation impairs Wnt/β-catenin signaling and causes loss of stemness in intestinal organoids ex vivo and primitive intestinal progenitors in vivo. Wnt/β-catenin-dependent liver metabolic zonation gene expression program is also down-regulated by mTORC1 activation. Our study provides a paradigm that mTORC1 signaling cell autonomously regulates Wnt/β-catenin pathway to influence stem cell maintenance.
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23
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Park SW, Seo MK, McIntyre RS, Mansur RB, Lee Y, Lee JH, Park SC, Huh L, Lee JG. Effects of olanzapine and haloperidol on mTORC1 signaling, dendritic outgrowth, and synaptic proteins in rat primary hippocampal neurons under toxic conditions. Neurosci Lett 2018; 686:59-66. [PMID: 30149032 DOI: 10.1016/j.neulet.2018.08.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 08/13/2018] [Accepted: 08/23/2018] [Indexed: 12/15/2022]
Abstract
Recent studies have demonstrated that antipsychotic drugs may activate mammalian target of rapamycin complex 1 (mTORC1) signaling in neurons. However, the relationship between mTORC1 signaling activation and currently prescribed antipsychotic drugs remains incompletely understood. The purpose of this study was to determine whether alterations in the level of mTORC1 signaling occur after rat primary hippocampal neurons are treated with olanzapine and haloperidol under toxic conditions. Additionally, we investigated whether these drugs affect dendritic outgrowth and synaptic protein expression through the mTORC1 signaling pathway. We measured changes in mTORC1-mediated and synaptic proteins by Western blotting assay under toxic conditions induced by B27 deprivation. Dendritic outgrowth was determined by a neurite assay. Olanzapine significantly increased the phosphorylated levels of mTORC1, its downstream effectors, and its upstream activators. The increased mTORC1 phosphorylation induced by olanzapine was significantly blocked by specific PI3K, MEK, or mTORC1 inhibitors. Olanzapine also increased dendritic outgrowth and synaptic proteins levels; all of these effects were blocked by rapamycin. However, haloperidol had none of these effects. We demonstrated that olanzapine, but not haloperidol, activated the mTORC1 signaling pathway and increased dendritic outgrowth and synaptic proteins by activating mTORC1 signaling in rat primary hippocampal neurons. These findings suggest that olanzapine affects neuroplasticity by activating mTORC1 signaling.
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Affiliation(s)
- Sung Woo Park
- Paik Institute for Clinical Research, Inje University, Busan, Republic of Korea; Department of Health Science and Technology, Graduate School, Inje University, Busan, Republic of Korea; Department of Convergence Biomedical Science, College of Medicine, Inje University, Busan, Republic of Korea
| | - Mi Kyoung Seo
- Paik Institute for Clinical Research, Inje University, Busan, Republic of Korea
| | - Roger S McIntyre
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Rodrigo B Mansur
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Yena Lee
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, Ontario, Canada
| | - Jae-Hon Lee
- Department of Psychiatry, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Republic of Korea
| | - Seon-Cheol Park
- Department of Psychiatry, College of Medicine, Haeundae Paik Hospital, Inje University, Busan, Republic of Korea
| | - Lyang Huh
- Department of Psychiatry, College of Medicine, Haeundae Paik Hospital, Inje University, Busan, Republic of Korea
| | - Jung Goo Lee
- Paik Institute for Clinical Research, Inje University, Busan, Republic of Korea; Department of Health Science and Technology, Graduate School, Inje University, Busan, Republic of Korea; Department of Psychiatry, College of Medicine, Haeundae Paik Hospital, Inje University, Busan, Republic of Korea.
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24
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Sánchez-Sánchez SM, Magdalon J, Griesi-Oliveira K, Yamamoto GL, Santacruz-Perez C, Fogo M, Passos-Bueno MR, Sertié AL. Rare RELN variants affect Reelin-DAB1 signal transduction in autism spectrum disorder. Hum Mutat 2018; 39:1372-1383. [PMID: 29969175 DOI: 10.1002/humu.23584] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 06/25/2018] [Accepted: 06/29/2018] [Indexed: 11/07/2022]
Abstract
The Reelin-DAB1 signaling pathway plays a crucial role in regulating neuronal migration and synapse function. Although many rare heterozygous variants in the Reelin gene (RELN) have been identified in patients with autism spectrum disorder (ASD), most variants are still of unknown clinical significance. Also, genetic data suggest that heterozygous variants in RELN alone appear to be insufficient to cause ASD. Here, we describe the identification and functional characterization of rare compound heterozygous missense variants in RELN in a patient with ASD in whom we have previously reported hyperfunctional mTORC1 signaling of yet unknown etiology. Using iPSC-derived neural progenitor cells (NPCs) from this patient, we provide experimental evidence that the identified variants are deleterious and lead to diminished Reelin secretion and impaired Reelin-DAB1 signal transduction. Also, our results suggest that mTORC1 pathway overactivation may function as a second hit event contributing to downregulation of the Reelin-DAB1 cascade in patient-derived NPCs, and that inhibition of mTORC1 by rapamycin attenuates Reelin-DAB1 signaling impairment. Taken together, our findings point to an abnormal interplay between Reelin-DAB1 and mTORC1 networks in nonsyndromic ASD.
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Affiliation(s)
- Sandra M Sánchez-Sánchez
- Center for Experimental Research, Hospital Israelita Albert Einstein, Sao Paulo, Brazil.,Department of Genetics and Evolutionary Biology, Sao Paulo University, Sao Paulo, Brazil
| | - Juliana Magdalon
- Center for Experimental Research, Hospital Israelita Albert Einstein, Sao Paulo, Brazil
| | | | - Guilherme L Yamamoto
- Department of Genetics and Evolutionary Biology, Sao Paulo University, Sao Paulo, Brazil
| | | | - Mariana Fogo
- Center for Experimental Research, Hospital Israelita Albert Einstein, Sao Paulo, Brazil.,Department of Genetics and Evolutionary Biology, Sao Paulo University, Sao Paulo, Brazil
| | | | - Andrea L Sertié
- Center for Experimental Research, Hospital Israelita Albert Einstein, Sao Paulo, Brazil
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25
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Yousefi M, Nakauka-Ddamba A, Berry CT, Li N, Schoenberger J, Bankler-Jukes D, Simeonov KP, Cedeno RJ, Yu Z, Lengner CJ. Calorie Restriction Governs Intestinal Epithelial Regeneration through Cell-Autonomous Regulation of mTORC1 in Reserve Stem Cells. Stem Cell Reports 2018; 10:703-711. [PMID: 29478893 PMCID: PMC5919411 DOI: 10.1016/j.stemcr.2018.01.026] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Revised: 01/20/2018] [Accepted: 01/22/2018] [Indexed: 12/22/2022] Open
Abstract
Aging is a complex process associated with a decline in functionality of adult stem cells affecting tissue homeostasis and regeneration. Calorie restriction (CR) is the only experimental manipulation known to extend lifespan and reduce the incidence of age-related disorders across numerous species. These benefits are likely mediated, at least in part, through the preservation of stem cell function. Here, we show that CR enhances the regenerative capacity of the intestinal epithelium through preservation of an injury-resistant reserve intestinal stem cell (ISC) pool. Cell-autonomous activity of mechanistic target of rapamycin complex 1 (mTORC1) governs the sensitivity of reserve ISCs to injury. CR inhibits mTORC1 in these cells, protecting them against DNA damage, while mTORC1 stimulation, either genetically or through nutrient sensing, sensitizes reserve ISCs to injury, thus compromising regeneration of the epithelium. These data delineate a critical role for mTORC1 in epithelial regeneration and inform clinical strategies based on nutrient modulation.
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Affiliation(s)
- Maryam Yousefi
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Cell and Molecular Biology Graduate Program, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Angela Nakauka-Ddamba
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Corbett T Berry
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ning Li
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jenna Schoenberger
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Devon Bankler-Jukes
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Cell and Molecular Biology Graduate Program, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kamen P Simeonov
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Cell and Molecular Biology Graduate Program, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ryan J Cedeno
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Cell and Molecular Biology Graduate Program, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Zhengquan Yu
- State Key Laboratories for Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Christopher J Lengner
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Cell and Molecular Biology Graduate Program, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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26
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Li Y, Finkbeiner S, Ganner A, Gerber J, Klein M, Grafe M, Kandzia J, Thien A, Thedieck K, Breves G, Jank T, Baumeister R, Walz G, Neumann-Haefelin E. CGEF-1 regulates mTORC1 signaling during adult longevity and stress response in C. elegans. Oncotarget 2018. [PMID: 29515755 PMCID: PMC5839386 DOI: 10.18632/oncotarget.24039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The mechanistic target of rapamycin (mTOR) kinase is central to metabolism and growth, and has a conserved role in aging. mTOR functions in two complexes, mTORC1 and mTORC2. In diverse eukaryotes, inhibition of mTORC1 signaling increases lifespan. mTORC1 transduces anabolic signals to stimulate protein synthesis and inhibits autophagy. In this study, we demonstrate that CGEF-1, the C. elegans homolog of the human guanine nucleotide exchange factor Dbl, is a novel binding partner of RHEB-1 and activator of mTORC1 signaling in C. elegans. cgef-1 mutants display prolonged lifespan and enhanced stress resistance. The transcription factors DAF-16/FoxO and SKN-1/Nrf are required for increased longevity and stress tolerance, and induce protective gene expression in cgef-1 mutants. Genetic evidence indicates that cgef-1 functions in the same pathway with rheb-1, the mTOR kinase let-363, and daf-15/Raptor. When cgef-1 is inactivated, phosphorylation of 4E-BP, a central mTORC1 substrate for protein translation is reduced in C. elegans. Moreover, autophagy is increased upon cgef-1 and mTORC1 inhibition. In addition, we show that in human cells Dbl associates with Rheb and stimulates mTORC1 downstream targets for protein synthesis suggesting that the function of CGEF-1/Dbl in the mTORC1 signaling pathway is evolutionarily conserved. These findings have important implications for mTOR functions and signaling mechanisms in aging and age-related diseases.
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Affiliation(s)
- Yujie Li
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Sandra Finkbeiner
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Athina Ganner
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Julia Gerber
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany.,Department of Physiology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Marinella Klein
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Manuel Grafe
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Jakob Kandzia
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Antje Thien
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany.,Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Kathrin Thedieck
- Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Gerhard Breves
- Department of Physiology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Thomas Jank
- Institute for Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
| | - Ralf Baumeister
- Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Centre for Biological Signaling Studies (BIOSS), Albert-Ludwigs-University of Freiburg, Freiburg, Germany.,Centre for Biological Systems Analysis (ZBSA), Albert-Ludwigs-University Freiburg, Freiburg, Germany.,ZBMZ Centre for Biochemistry and Molecular Cell Research, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Gerd Walz
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany.,Centre for Biological Signaling Studies (BIOSS), Albert-Ludwigs-University of Freiburg, Freiburg, Germany
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27
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Vandoorne T, De Smet S, Ramaekers M, Van Thienen R, De Bock K, Clarke K, Hespel P. Intake of a Ketone Ester Drink during Recovery from Exercise Promotes mTORC1 Signaling but Not Glycogen Resynthesis in Human Muscle. Front Physiol 2017; 8:310. [PMID: 28588499 PMCID: PMC5440563 DOI: 10.3389/fphys.2017.00310] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 04/28/2017] [Indexed: 01/07/2023] Open
Abstract
Purpose: Ketone bodies are energy substrates produced by the liver during prolonged fasting or low-carbohydrate diet. The ingestion of a ketone ester (KE) rapidly increases blood ketone levels independent of nutritional status. KE has recently been shown to improve exercise performance, but whether it can also promote post-exercise muscle protein or glycogen synthesis is unknown. Methods: Eight healthy trained males participated in a randomized double-blind placebo-controlled crossover study. In each session, subjects undertook a bout of intense one-leg glycogen-depleting exercise followed by a 5-h recovery period during which they ingested a protein/carbohydrate mixture. Additionally, subjects ingested a ketone ester (KE) or an isocaloric placebo (PL). Results: KE intake did not affect muscle glycogen resynthesis, but more rapidly lowered post-exercise AMPK phosphorylation and resulted in higher mTORC1 activation, as evidenced by the higher phosphorylation of its main downstream targets S6K1 and 4E-BP1. As enhanced mTORC1 activation following KE suggests higher protein synthesis rates, we used myogenic C2C12 cells to further confirm that ketone bodies increase both leucine-mediated mTORC1 activation and protein synthesis in muscle cells. Conclusion: Our results indicate that adding KE to a standard post-exercise recovery beverage enhances the post-exercise activation of mTORC1 but does not affect muscle glycogen resynthesis in young healthy volunteers. In vitro, we confirmed that ketone bodies potentiate the increase in mTORC1 activation and protein synthesis in leucine-stimulated myotubes. Whether, chronic oral KE intake during recovery from exercise can facilitate training-induced muscular adaptation and remodeling need to be further investigated.
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Affiliation(s)
- Tijs Vandoorne
- Exercise Physiology Research Group, Department of Kinesiology, KU LeuvenLeuven, Belgium
| | - Stefan De Smet
- Exercise Physiology Research Group, Department of Kinesiology, KU LeuvenLeuven, Belgium
| | - Monique Ramaekers
- Exercise Physiology Research Group, Department of Kinesiology, KU LeuvenLeuven, Belgium
| | - Ruud Van Thienen
- Exercise Physiology Research Group, Department of Kinesiology, KU LeuvenLeuven, Belgium
| | - Katrien De Bock
- Exercise Physiology Research Group, Department of Kinesiology, KU LeuvenLeuven, Belgium.,Laboratory of Exercise and Health, Department of Health Sciences and Technology, ETH ZurichZurich, Switzerland
| | - Kieran Clarke
- Department of Physiology, Anatomy and Genetics, University of OxfordOxford, United Kingdom
| | - Peter Hespel
- Exercise Physiology Research Group, Department of Kinesiology, KU LeuvenLeuven, Belgium
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Agergaard J, Bülow J, Jensen JK, Reitelseder S, Drummond MJ, Schjerling P, Scheike T, Serena A, Holm L. Light-load resistance exercise increases muscle protein synthesis and hypertrophy signaling in elderly men. Am J Physiol Endocrinol Metab 2017; 312:E326-E338. [PMID: 27780819 DOI: 10.1152/ajpendo.00164.2016] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 09/06/2016] [Accepted: 10/05/2016] [Indexed: 01/18/2023]
Abstract
The present study investigated whether well-tolerated light-load resistance exercise (LL-RE) affects skeletal muscle fractional synthetic rate (FSR) and anabolic intracellular signaling as a way to counteract age-related loss of muscle mass. Untrained healthy elderly (>65-yr-old) men were subjected to 13 h of supine rest. After 2.5 h of rest, unilateral LL-RE, consisting of leg extensions (10 sets, 36 repetitions) at 16% of 1 repetition maximum (RM), was conducted. Subsequently, the subjects were randomized to oral intake of 4 g of whey protein per hour (PULSE, n = 10), 28 g of whey protein at 0 h and 12 g of whey protein at 7 h postexercise (BOLUS, n = 10), or 4 g of maltodextrin per hour (placebo, n = 10). Quadriceps muscle biopsies were taken at 0, 3, 7, and 10 h postexercise from the resting and the exercised leg of each subject. Myofibrillar FSR and activity of select targets from the mechanistic target of rapamycin complex 1-signaling cascade were analyzed from the biopsies. LL-RE increased myofibrillar FSR compared with the resting leg throughout the 10-h postexercise period. Phosphorylated (T308) AKT expression increased in the exercised leg immediately after exercise. This increase persisted in the placebo group only. Levels of phosphorylated (T37/46) eukaryotic translation initiation factor 4E-binding protein 1 increased throughout the postexercise period in the exercised leg in the placebo and BOLUS groups and peaked at 7 h. In all three groups, phosphorylated (T56) eukaryotic elongation factor 2 decreased in response to LL-RE. We conclude that resistance exercise at only 16% of 1 RM increased myofibrillar FSR, irrespective of nutrient type and feeding pattern, which indicates an anabolic effect of LL-RE in elderly individuals. This finding was supported by increased signaling for translation initiation and translation elongation in response to LL-RE.
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Affiliation(s)
- Jakob Agergaard
- Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Ageing, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark;
- Department of Physical Therapy, University of Utah, Salt Lake City, Utah
| | - Jacob Bülow
- Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Ageing, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jacob K Jensen
- Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Ageing, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Søren Reitelseder
- Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Ageing, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Micah J Drummond
- Department of Physical Therapy, University of Utah, Salt Lake City, Utah
| | - Peter Schjerling
- Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Ageing, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Scheike
- Department of Biostatistics, Institute of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; and
| | - Anja Serena
- Arla Foods Ingredients Group P/S, Viby, Denmark
| | - Lars Holm
- Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Ageing, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Wu H, Wang Y, Wang X, Li R, Yin D. MicroRNA-365 accelerates cardiac hypertrophy by inhibiting autophagy via the modulation of Skp2 expression. Biochem Biophys Res Commun 2017; 484:304-10. [PMID: 28130111 DOI: 10.1016/j.bbrc.2017.01.108] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 01/21/2017] [Indexed: 01/15/2023]
Abstract
Evidence is emerging of a tight link between cardiomyocyte autophagy and cardiac hypertrophy (CH). Sustained exposure to stress leads CH to progress to heart failure. Several miRNAs have been described in heart failure, and miRNA-based therapeutic approaches are being pursued. Although microRNA-365 (miR-365) has been testified as a positive modulator of CH, the specific mechanism remains unclear. In the present study, we observed that miR-365 expression was up-regulated in hypertrophic cardiomyocytes both in vivo and in vitro, and was accompanied by dysregulation of autophagy. We found that miR-365 negatively modulates autophagy in hypertrophic cardiomyocytes by targeting Skp2. Overexpression of Skp2 promoted autophagy and rescued CH induced by Ang-II; conversely, Skp2 knockdown further inhibited autophagy and CH. Furthermore, we found that the activation of mammalian target of rapamycin (mTOR) signaling was regulated by Skp2 following Ang-II treatment, as indicated by the up-regulation of p-S6K and p-4EBP1 levels. The inactivation of mTOR by rapamycin completely abolished the Ang-II-induced inhibition of autophagy. In conclusion, our study provides substantial evidence that miR-365 and its target gene Skp2 play a functional role in CH and suggests the development of novel therapeutic options based on miR-365 and Skp2.
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Xia J, Wang R, Zhang T, Ding J. Structural insight into the arginine-binding specificity of CASTOR1 in amino acid-dependent mTORC1 signaling. Cell Discov 2016; 2:16035. [PMID: 27648300 PMCID: PMC5020642 DOI: 10.1038/celldisc.2016.35] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 08/30/2016] [Indexed: 12/25/2022] Open
Abstract
The mechanistic Target Of Rapamycin Complex 1 (mTORC1) is central to the cellular response to changes in nutrient signals such as amino acids. CASTOR1 is shown to be an arginine sensor, which plays an important role in the activation of the mTORC1 pathway. In the deficiency of arginine, CASTOR1 interacts with GATOR2, which together with GATOR1 and Rag GTPases controls the relocalization of mTORC1 to lysosomes. The binding of arginine to CASTOR1 disrupts its association with GATOR2 and hence activates the mTORC1 signaling. Here, we report the crystal structure of CASTOR1 in complex with arginine at 2.5 Å resolution. CASTOR1 comprises of four tandem ACT domains with an architecture resembling the C-terminal allosteric domains of aspartate kinases. ACT1 and ACT3 adopt the typical βαββαβ topology and function in dimerization via the conserved residues from helices α1 of ACT1 and α5 of ACT3; whereas ACT 2 and ACT4, both comprising of two non-sequential regions, assume the unusual ββαββα topology and contribute an arginine-binding pocket at the interface. The bound arginine makes a number of hydrogen-bonding interactions and extensive hydrophobic contacts with the surrounding residues of the binding pocket. The functional roles of the key residues are validated by mutagenesis and biochemical assays. Our structural and functional data together reveal the molecular basis for the arginine-binding specificity of CASTOR1 in the arginine-dependent activation of the mTORC1 signaling.
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Affiliation(s)
- Jing Xia
- School of Life Sciences, Shanghai University , Shanghai, China
| | - Rong Wang
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China
| | - Tianlong Zhang
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China
| | - Jianping Ding
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; Shanghai Science Research Center, Chinese Academy of Sciences, Shanghai, China
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Seo MK, McIntyre RS, Cho HY, Lee CH, Park SW, Mansur RB, Kim GM, Baek JH, Woo YS, Lee JG, Kim YH. Tianeptine induces mTORC1 activation in rat hippocampal neurons under toxic conditions. Psychopharmacology (Berl) 2016; 233:2617-27. [PMID: 27129862 DOI: 10.1007/s00213-016-4309-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 04/22/2016] [Indexed: 12/23/2022]
Abstract
RATIONALE Recent studies have demonstrated that mTORC1 activation may be related to antidepressant action. However, the relationship between mTORC1 signaling activation and currently prescribed antidepressants remains unclear. OBJECTIVE The aim of the present study was to determine whether alterations in mTORC1 signaling are observable following treatment with tianeptine under toxic conditions induced by B27 deprivation. Additionally, we investigated whether this drug affects synaptic proteins, neurite outgrowth, and spine density via mTORC1 signaling. METHODS Using Western blotting, we measured the phosphorylation levels of mTORC1, 4E-BP-1, p70S6K, Akt, and ERK in rat primary hippocampal neurons. Changes in BDNF, dendritic outgrowth, spine density, and synaptic proteins (PSD-95, synaptophysin, and GluR1) were measured. RESULTS Tianeptine significantly increased the phosphorylation of mTORC1, 4E-BP-1, p70S6K, Akt, and ERK. The increase in mTOR phosphorylation was blocked by the PI3K, MEK, and mTORC1 inhibitors. Tianeptine increased BDNF, dendritic outgrowth, spine density, and synaptic proteins; all of these effects were blocked by the mTORC1 inhibitor. CONCLUSIONS In this study, we demonstrated that tianeptine activates the mTORC1 signaling pathway and increases dendritic outgrowth, spine density, and synaptic proteins through mTORC1 signaling under toxic conditions in rat primary hippocampal neurons.
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Affiliation(s)
- Mi Kyoung Seo
- Paik Institute for Clinical Research, Inje University, Busan, Republic of Korea
| | - Roger S McIntyre
- Mood Disorders Psychopharmacology Unit, University Health Network, University of Toronto, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Hye Yeon Cho
- Paik Institute for Clinical Research, Inje University, Busan, Republic of Korea
| | - Chan Hong Lee
- Paik Institute for Clinical Research, Inje University, Busan, Republic of Korea
| | - Sung Woo Park
- Paik Institute for Clinical Research, Inje University, Busan, Republic of Korea
- Department of Health Science and Technology, Graduate School, Inje University, Busan, Republic of Korea
| | - Rodrigo B Mansur
- Mood Disorders Psychopharmacology Unit, University Health Network, University of Toronto, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Gyung-Mee Kim
- Department of Psychiatry, School of Medicine, Haeundae Paik Hospital, Inje University, Busan, Republic of Korea
| | - Jun Hyung Baek
- Department of Psychiatry, School of Medicine, Haeundae Paik Hospital, Inje University, Busan, Republic of Korea
| | - Young Sup Woo
- Department of Psychiatry, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jung Goo Lee
- Paik Institute for Clinical Research, Inje University, Busan, Republic of Korea.
- Mood Disorders Psychopharmacology Unit, University Health Network, University of Toronto, Toronto, ON, Canada.
- Department of Health Science and Technology, Graduate School, Inje University, Busan, Republic of Korea.
- Department of Psychiatry, School of Medicine, Haeundae Paik Hospital, Inje University, Busan, Republic of Korea.
- Department of Psychiatry, Inje University Haeundae Paik Hospital, 1435, Jwa-dong, Haeundae-gu, Busan, 612-030, Republic of Korea.
| | - Young Hoon Kim
- Paik Institute for Clinical Research, Inje University, Busan, Republic of Korea.
- Department of Health Science and Technology, Graduate School, Inje University, Busan, Republic of Korea.
- Department of Psychiatry, School of Medicine, Haeundae Paik Hospital, Inje University, Busan, Republic of Korea.
- Department of Psychiatry, Inje University Haeundae Paik Hospital, 1435, Jwa-dong, Haeundae-gu, Busan, 612-030, Republic of Korea.
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Kido K, Sato K, Makanae Y, Ato S, Hayashi T, Fujita S. Herbal supplement Kamishimotsuto augments resistance exercise-induced mTORC1 signaling in rat skeletal muscle. Nutrition 2015; 32:108-13. [PMID: 26423232 DOI: 10.1016/j.nut.2015.06.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 05/12/2015] [Accepted: 06/30/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVES Kamishimotsuto (KST) is a supplement containing 13 different herbs including Phellodendron bark, Anemarrhena rhizome and ginseng that have been shown to activate mammalian target of rapamycin complex 1 (mTORC1) and thereby increase muscle protein synthesis in vitro. However, the combined effect of KST and resistance exercise on muscle protein anabolism has not been investigated in vivo. Therefore, the purpose of this study was to investigate the effect of KST supplementation, resistance exercise on (mTORC1) signaling and subsequent muscle protein synthesis. METHODS Male Sprague-Dawley rats were divided into two groups: one group received KST (500 mg/kg/d in water) and the other group received placebo (PLA) for 7 d. After 12 h of fasting, the right gastrocnemius muscle was isometrically exercised via percutaneous electrical stimulation. Muscle samples were analyzed for muscle protein synthesis (MPS) and by western blotting analysis to assess the phosphorylation of p70S6K (Thr389), rpS6 (Ser240/244), and Akt (Ser473 and Thr308). RESULTS KST supplementation for 7 d significantly increased basal p-Akt (Ser473) levels compared with PLA, phosphorylation of the signaling proteins and MPS at baseline were otherwise unaffected. p-p70S6K and p-rpS6 levels significantly increased 1 h and 3 h after exercise in the PLA group, and these elevations were augmented in the KST group (P < 0.05). Furthermore, MPS at 6 h after resistance exercise was greater in the KST group than in the PLA group (P < 0.05). CONCLUSIONS While resistance exercise alone was able to increase p70S6K and rpS6 phosphorylation, Kamishimotsuto supplementation further augmented resistance exercise-induced muscle protein synthesis through mTORC1 signaling.
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Affiliation(s)
- Kohei Kido
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Koji Sato
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Yuhei Makanae
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Satoru Ato
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Tadahiro Hayashi
- R&D Center, Kobayashi Pharmaceutical Co., Ltd., Ibaraki, Osaka, Japan
| | - Satoshi Fujita
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan.
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Affiliation(s)
- Gerard Apodaca
- The Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh Pittsburgh, PA, USA
| | - William J Brown
- Molecular Biology and Genetics, Cornell University Ithaca, NY, USA
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Abstract
Target of rapamycin (TOR) was first identified in yeast as a target molecule of rapamycin, an anti-fugal and immunosuppressant macrolide compound. In mammals, its orthologue is called mammalian TOR (mTOR). mTOR is a serine/threonine kinase that converges different extracellular stimuli, such as nutrients and growth factors, and diverges into several biochemical reactions, including translation, autophagy, transcription, and lipid synthesis among others. These biochemical reactions govern cell growth and cause cells to attain an anabolic state. Thus, the disruption of mTOR signaling is implicated in a wide array of diseases such as cancer, diabetes, and obesity. In the central nervous system, the mTOR signaling cascade is activated by nutrients, neurotrophic factors, and neurotransmitters that enhances protein (and possibly lipid) synthesis and suppresses autophagy. These processes contribute to normal neuronal growth by promoting their differentiation, neurite elongation and branching, and synaptic formation during development. Therefore, disruption of mTOR signaling may cause neuronal degeneration and abnormal neural development. While reduced mTOR signaling is associated with neurodegeneration, excess activation of mTOR signaling causes abnormal development of neurons and glia, leading to brain malformation. In this review, we first introduce the current state of molecular knowledge of mTOR complexes and signaling in general. We then describe mTOR activation in neurons, which leads to translational enhancement, and finally discuss the link between mTOR and normal/abnormal neuronal growth during development.
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Affiliation(s)
- Nobuyuki Takei
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University Niigata, Japan
| | - Hiroyuki Nawa
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University Niigata, Japan
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Lu W, Lin C, Li Y. Rottlerin induces Wnt co-receptor LRP6 degradation and suppresses both Wnt/β-catenin and mTORC1 signaling in prostate and breast cancer cells. Cell Signal 2014; 26:1303-9. [PMID: 24607787 DOI: 10.1016/j.cellsig.2014.02.018] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 02/10/2014] [Accepted: 02/22/2014] [Indexed: 02/06/2023]
Abstract
Activation of Wnt/β-catenin signaling can result in up-regulation of mTORC1 signaling in cancer cells. The low density lipoprotein receptor-related protein-6 (LRP6) is an essential Wnt co-receptor for Wnt/β-catenin signaling. We found that rottlerin, a natural plant polyphenol, suppressed LRP6 expression and phosphorylation, and inhibited Wnt/β-catenin signaling in HEK293 cells. Furthermore, the inhibitory effects of rottlerin on LRP6 expression/phosphorylation and Wnt/β-catenin signaling were confirmed in human prostate cancer PC-3 and DU145 cells and breast cancer MDA-MB-231 and T-47D cells. Mechanistically, rottlerin promoted LRP6 degradation, but had no effects on LRP6 transcriptional activity. In addition, rottlerin-mediated LRP6 down-regulation was unrelated to activation of 5'-AMP-activated protein kinase (AMPK). Importantly, we also found that rottlerin inhibited mTORC1 signaling in prostate and breast cancer cells. Finally, we demonstrated that rottlerin was able to suppress the expression of cyclin D1 and survivin, two targets of both Wnt/β-catenin and mTORC1 signaling, in prostate and breast cancer cells, and displayed remarkable anticancer activity with IC(50) values between 0.7 and 1.7 μM for prostate cancer PC-3 and DU145 cells and breast cancer MDA-MB-231 and T-47D cells. The IC(50) values are comparable to those shown to suppress the activities of Wnt/β-catenin and mTORC1 signaling in prostate and breast cancer cells. Our data indicate that rottlerin is a novel LRP6 inhibitor and suppresses both Wnt/β-catenin and mTORC1 signaling in prostate and breast cancer cells, and that LRP6 represents a potential therapeutic target for cancers.
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Affiliation(s)
- Wenyan Lu
- Department of Biochemistry and Molecular Biology, Drug Discovery Division, Southern Research Institute, 2000 Ninth Avenue South, Birmingham, AL 35255, USA
| | - Cuihong Lin
- Department of Biochemistry and Molecular Biology, Drug Discovery Division, Southern Research Institute, 2000 Ninth Avenue South, Birmingham, AL 35255, USA; Department of Pharmacy, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Yonghe Li
- Department of Biochemistry and Molecular Biology, Drug Discovery Division, Southern Research Institute, 2000 Ninth Avenue South, Birmingham, AL 35255, USA.
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Abstract
Diabetes mellitus (DM) is the most common cause of chronic kidney disease and end stage renal disease. New onset diabetes mellitus after transplant (NODAT) has been described in approximately 30% of non-diabetic kidney-transplant recipients many years post transplantation. DM in patients with kidney transplantation constitutes a major comorbidity, and has significant impact on the patients and allografts' outcome. In addition to the major comorbidity and mortality that result from cardiovascular and other DM complications, long standing DM after kidney-transplant has significant pathological injury to the allograft, which results in lowering the allografts and the patients' survivals. In spite of the cumulative body of data on diabetic nephropathy (DN) in the native kidney, there has been very limited data on the DN in the transplanted kidney. In this review, we will shed the light on the risk factors that lead to the development of NODAT. We will also describe the impact of DM on the transplanted kidney, and the outcome of kidney-transplant recipients with NODAT. Additionally, we will present the most acceptable data on management of NODAT.
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Affiliation(s)
- Vasil Peev
- Department of Medicine, Rush University School of Medicine, Chicago, IL, USA
| | - Jochen Reiser
- Department of Medicine, Rush University School of Medicine, Chicago, IL, USA
- *Correspondence: Jochen Reiser, Rush University Medical Center, 1735 West Harrison Street, Cohn Building, Suite 724, Chicago, IL 60612, USA e-mail:
| | - Nada Alachkar
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Gu X, Yu JJ, Ilter D, Blenis N, Henske EP, Blenis J. Integration of mTOR and estrogen-ERK2 signaling in lymphangioleiomyomatosis pathogenesis. Proc Natl Acad Sci U S A 2013; 110:14960-5. [PMID: 23983265 DOI: 10.1073/pnas.1309110110] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Lymphangioleiomyomatosis (LAM) is a destructive lung disease of women associated with the metastasis of tuberin-null cells with hyperactive mammalian target of rapamycin complex 1 (mTORC1) activity. Clinical trials with the mTORC1 inhibitor rapamycin have revealed partial efficacy but are not curative. Pregnancy appears to exacerbate LAM, suggesting that estrogen (E2) may play a role in the unique features of LAM. Using a LAM patient-derived cell line (bearing biallelic Tuberin inactivation), we demonstrate that E2 stimulates a robust and biphasic activation of ERK2 and transcription of the late response-gene Fra1 associated with epithelial-to-mesenchymal transition. In a carefully orchestrated collaboration, activated mTORC1/S6K1 signaling enhances the efficiency of Fra1 translation of Fra1 mRNA transcribed by the E2-ERK2 pathway, through the phosphorylation of the S6K1-dependent eukaryotic translation initiation factor 4B. Our results indicate that targeting the E2-ERK pathway in combination with the mTORC1 pathway may be an effective combination therapy for LAM.
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Santini E, Klann E. Dysregulated mTORC1-Dependent Translational Control: From Brain Disorders to Psychoactive Drugs. Front Behav Neurosci 2011; 5:76. [PMID: 22073033 PMCID: PMC3210466 DOI: 10.3389/fnbeh.2011.00076] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 10/21/2011] [Indexed: 01/09/2023] Open
Abstract
In the last decade, a plethora of studies utilizing pharmacological, biochemical, and genetic approaches have shown that precise translational control is required for long-lasting synaptic plasticity and the formation of long-term memory. Moreover, more recent studies indicate that alterations in translational control are a common pathophysiological feature of human neurological disorders, including developmental disorders, neuropsychiatric disorders, and neurodegenerative diseases. Finally, translational control mechanisms are susceptible to modification by psychoactive drugs. Taken together, these findings point to a central role for translational control in the regulation of synaptic function and behavior.
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Affiliation(s)
- Emanuela Santini
- Center for Neural Science, New York University New York, NY, USA
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