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Tang X, Liu H, Wang X, Chang L, Liu Q, Xia Q, Zhao P. BmSLC7A5 is essential for silk protein synthesis and larval development in Bombyx mori. INSECT SCIENCE 2024; 31:1425-1439. [PMID: 38284747 DOI: 10.1111/1744-7917.13314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 11/10/2023] [Accepted: 11/14/2023] [Indexed: 01/30/2024]
Abstract
Insects produce silk to form cocoons, nests, and webs, which are important for their survival and reproduction. However, little is known about the molecular mechanism of silk protein synthesis at the translation level. The solute carrier family 7 (SLC7) genes are involved in activating the target of rapamycin complex 1 (TORC1) signaling pathway and protein translation process, but the physiological roles of SLC7 genes in silk-producing insects have not been reported. Here, we found that amino acid signaling regulates silk protein synthesis and larval development via the L-type amino acid transporter 1 (LAT1; also known as SLC7A5) in Bombyx mori. A total of 12 SLC7 homologs were identified in the silkworm genome, among which BmSLC7A5 was found to be a silk gland-enriched gene and may be involved in leucine transport. Bioinformatics analysis indicated that SLC7A5 displays high homology and a close phylogenetic relationship in silk-producing insects. Subsequently, we found that leucine treatment significantly increased silk protein synthesis by improving the transcription and protein levels of silk genes. Furthermore, systemic and silk gland-specific knockout of BmSLC7A5 led to decreased silk protein synthesis by inhibiting TORC1 signaling, and somatic mutation also resulted in arrested development from the 5th instar to the early pupal stage. Altogether, our study reveals that BmSLC7A5 is involved in regulating silk protein synthesis and larval development by affecting the TORC1 signaling pathway, which provides a new strategy and target for improving silk yield.
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Affiliation(s)
- Xin Tang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Chinese Medicine & Health Science, Chongqing Academy of Chinese Materia Medica, Chongqing College of Traditional Chinese Medicine, Chongqing, China
| | - Huawei Liu
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Xin Wang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Li Chang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Qingsong Liu
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Qingyou Xia
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Ping Zhao
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
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Zhu H, Auten RL, Whorton AR, Mason SN, Bock CB, Kucera GT, Kelleher ZT, Vose AT, McMahon TJ. Endothelial LAT1 (SLC7A5) Mediates S-Nitrosothiol Import and Modulates Respiratory Sequelae of Red Blood Cell Transfusion In Vivo. Thromb Haemost 2024; 124:656-668. [PMID: 38519039 PMCID: PMC11199053 DOI: 10.1055/s-0044-1782182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 01/03/2024] [Indexed: 03/24/2024]
Abstract
BACKGROUND Increased adhesivity of red blood cells (RBCs) to endothelial cells (ECs) may contribute to organ dysfunction in malaria, sickle cell disease, and diabetes. RBCs normally export nitric oxide (NO)-derived vascular signals, facilitating blood flow. S-nitrosothiols (SNOs) are thiol adducts formed in RBCs from precursor NO upon the oxygenation-linked allosteric transition in hemoglobin. RBCs export these vasoregulatory SNOs on demand, thereby regulating regional blood flow and preventing RBC-EC adhesion, and the large (system L) neutral amino acid transporter 1 (LAT1; SLC7A5) appears to mediate SNO export by RBCs. METHODS To determine the role of LAT1-mediated SNO import by ECs generally and of LAT1-mediated SNO import by ECs in RBC SNO-dependent modulation of RBC sequestration and blood oxygenation in vivo, we engineered LAT1fl/fl; Cdh5-Cre+ mice, in which the putative SNO transporter LAT1 can be inducibly depleted (knocked down, KD) specifically in ECs ("LAT1ECKD"). RESULTS We show that LAT1 in mouse lung ECs mediates cellular SNO uptake. ECs from LAT1ECKD mice (tamoxifen-induced LAT1fl/fl; Cdh5-Cre+) import SNOs poorly ex vivo compared with ECs from wild-type (tamoxifen-treated LAT1fl/fl; Cdh5-Cre-) mice. In vivo, endothelial depletion of LAT1 increased RBC sequestration in the lung and decreased blood oxygenation after RBC transfusion. CONCLUSION This is the first study showing a role for SNO transport by LAT1 in ECs in a genetic mouse model. We provide the first direct evidence for the coordination of RBC SNO export with EC SNO import via LAT1. SNO flux via LAT1 modulates RBC-EC sequestration in lungs after transfusion, and its disruption impairs blood oxygenation by the lung.
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Affiliation(s)
- Hongmei Zhu
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States
- Durham VA Health Care System, Durham North Carolina, United States
| | - Richard L. Auten
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, United States
| | - Augustus Richard Whorton
- Department of Pharmacology, Duke University Medical Center, Durham, North Carolina, United States
| | - Stanley Nicholas Mason
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, United States
| | - Cheryl B. Bock
- Rodent Cancer Models Shared Resource, Duke University Medical Center, Durham, North Carolina, United States
| | - Gary T. Kucera
- Rodent Cancer Models Shared Resource, Duke University Medical Center, Durham, North Carolina, United States
| | - Zachary T. Kelleher
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States
| | - Aaron T. Vose
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States
- Durham VA Health Care System, Durham North Carolina, United States
| | - Tim J. McMahon
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States
- Durham VA Health Care System, Durham North Carolina, United States
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Rosario FJ, Barentsen K, Powell TL, Urschitz J, Brown TL, Kanai Y, Jansson T. Trophoblast-specific overexpression of the LAT1 increases transplacental transport of essential amino acids and fetal growth in mice. PNAS NEXUS 2024; 3:pgae207. [PMID: 38894879 PMCID: PMC11184900 DOI: 10.1093/pnasnexus/pgae207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 05/17/2024] [Indexed: 06/21/2024]
Abstract
Placental System L amino acid transporter activity is decreased in pregnancies complicated by intrauterine growth restriction (IUGR) and increased in fetal overgrowth. However, it is unknown if changes in the expression/activity of placental Large Neutral Amino Acid Transporter Small Subunit 1 (Slc7a5/LAT1) are mechanistically linked to placental function and fetal growth. We hypothesized that trophoblast-specific Slc7a5 overexpression increases placental transport of essential amino acids, activates the placental mechanistic target of rapamycin (mTOR) signaling, and promotes fetal growth in mice. Using lentiviral transduction of blastocysts with a Slc7a5 transgene, we achieved trophoblast-specific overexpression of Slc7a5 (Slc7a5 OX) with increased fetal (+27%) and placental weights (+10%). Trophoblast-specific Slc7a5 overexpression increased trophoblast plasma membrane (TPM) LAT1 protein abundance and TPM System L transporter (+53%) and System A transporter activity (+ 21%). Slc7a5 overexpression also increased transplacental transport of leucine (+ 85%) but not of the System A tracer, 14C-methylamino isobutyric acid, in vivo. Trophoblast-specific overexpression of Slc7a5 activated placental mTORC1, as assessed by increased (+44%) phosphorylation of S6 ribosomal protein (Ser 235/236), and mTORC2 as indicated by phosphorylation of PKCα-Tyr-657 (+47%) and Akt-Ser 473 (+96%). This is the first demonstration that placental transport of essential amino acids is mechanistically linked to fetal growth. The decreased placental System L activity in human IUGR and the increased placental activity of this transporter in some cases of fetal overgrowth may directly contribute to the development of these pregnancy complications.
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Affiliation(s)
- Fredrick J Rosario
- Department of Obstetrics and Gynecology, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Kenneth Barentsen
- Department of Obstetrics and Gynecology, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Theresa L Powell
- Department of Obstetrics and Gynecology, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
- Section of Neonatology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Johann Urschitz
- Institue of Biogenesis, University of Hawaii, Honolulu, HI 96822, USA
| | - Thomas L Brown
- Department of Neuroscience, Cell Biology, and Physiology, Wright State University Boonshoft School of Medicine, Dayton, OH 45435, USA
| | - Yoshikatsu Kanai
- Department of Bio-system Pharmacology, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
| | - Thomas Jansson
- Department of Obstetrics and Gynecology, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
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Bao L, Fu L, Su Y, Chen Z, Peng Z, Sun L, Gonzalez FJ, Wu C, Zhang H, Shi B, Shi YB. Amino acid transporter SLC7A5 regulates cell proliferation and secretary cell differentiation and distribution in the mouse intestine. Int J Biol Sci 2024; 20:2187-2201. [PMID: 38617535 PMCID: PMC11008275 DOI: 10.7150/ijbs.94297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 02/16/2024] [Indexed: 04/16/2024] Open
Abstract
The intestine is critical for not only processing nutrients but also protecting the organism from the environment. These functions are mainly carried out by the epithelium, which is constantly being self-renewed. Many genes and pathways can influence intestinal epithelial cell proliferation. Among them is mTORC1, whose activation increases cell proliferation. Here, we report the first intestinal epithelial cell (IEC)-specific knockout (ΔIEC) of an amino acid transporter capable of activating mTORC1. We show that the transporter, SLC7A5, is highly expressed in mouse intestinal crypt and Slc7a5ΔIEC reduces mTORC1 signaling. Surprisingly, adult Slc7a5ΔIEC intestinal crypts have increased cell proliferation but reduced mature Paneth cells. Goblet cells, the other major secretory cell type in the small intestine, are increased in the crypts but reduced in the villi. Analyses with scRNA-seq and electron microscopy have revealed dedifferentiation of Paneth cells in Slc7a5ΔIEC mice, leading to markedly reduced secretory granules with little effect on Paneth cell number. Thus, SLC7A5 likely regulates secretory cell differentiation to affect stem cell niche and indirectly regulate cell proliferation.
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Affiliation(s)
- Lingyu Bao
- Section on Molecular Morphogenesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, MD, USA
- Department of Endocrinology, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine. No.277, Yanta West Road, Xi'an, Shaanxi, 710061, P.R. China
| | - Liezhen Fu
- Section on Molecular Morphogenesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, MD, USA
| | - Yijun Su
- Laboratory of High Resolution Optical Imaging and Advanced Imaging and Microscopy Resource, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, 20892, USA
- Janelia Research Campus, Howard Hughes Medical Institute (HHMI), Ashburn, VA, USA
| | - Zuojia Chen
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zhaoyi Peng
- Section on Molecular Morphogenesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, MD, USA
- Department of Endocrinology, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine. No.277, Yanta West Road, Xi'an, Shaanxi, 710061, P.R. China
| | - Lulu Sun
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Frank J. Gonzalez
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Chuan Wu
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hongen Zhang
- Bioinformatics and Scientific Programming Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Bingyin Shi
- Department of Endocrinology, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine. No.277, Yanta West Road, Xi'an, Shaanxi, 710061, P.R. China
| | - Yun-Bo Shi
- Section on Molecular Morphogenesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, MD, USA
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Kumar A, Bellar A, Mishra S, Sekar J, Welch N, Dasarathy S. L-Isoleucine reverses hyperammonemia-induced myotube mitochondrial dysfunction and post-mitotic senescence. J Nutr Biochem 2024; 123:109498. [PMID: 37871767 PMCID: PMC10841977 DOI: 10.1016/j.jnutbio.2023.109498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 10/16/2023] [Accepted: 10/19/2023] [Indexed: 10/25/2023]
Abstract
Perturbations in the metabolism of ammonia, a cytotoxic endogenous metabolite, occur in a number of chronic diseases, with consequent hyperammonemia. Increased skeletal muscle ammonia uptake causes metabolic, molecular, and phenotype alterations including cataplerosis of (loss of tricarboxylic acid cycle (TCA) cycle intermediate) α-ketoglutarate (αKG), mitochondrial oxidative dysfunction, and senescence-associated molecular phenotype (SAMP). L-Isoleucine (Ile) is an essential, branched-chain amino acid (BCAA) that simultaneously provides acetyl-CoA as an oxidative substrate and succinyl-CoA for anaplerosis (providing TCA cycle intermediates). Our multiomics analyses in myotubes and skeletal muscle from hyperammonemic mice and human patients with cirrhosis showed perturbations in BCAA transporters and catabolism. We, therefore, determined if Ile reverses hyperammonemia-induced impaired mitochondrial oxidative function and SAMP. Studies were performed in differentiated murine C2C12 myotubes that were early passage, late passage (senescent), or those depleted of LAT1/SLC7A5 and human induced pluripotent stem cell-derived myotubes (hiPSCM). Ile reverses hyperammonemia-induced reduction in the maximum respiratory capacity, complex I, II, and III functions in early passage murine myotubes and hiPSCM. Consistently, low ATP content and impaired global protein synthesis (high energy requiring cellular process) during hyperammonemia are reversed by Ile in murine myotubes and hiPSCM. Lower abundance of critical regulators of protein synthesis in mTORC1 signaling, and increased phosphorylation of eukaryotic initiation factor 2α are also reversed by Ile. Genetic depletion studies showed that Ile responses are independent of the amino acid transporter LAT1/SLC7A5. Our studies show that Ile reverses the hyperammonemia-induced impaired mitochondrial oxidative function, cataplerosis, and SAMP in a LAT1/SLC7A5 transporter-independent manner.
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Affiliation(s)
- Avinash Kumar
- Department of Gastroenterology, Hepatology and Nutrition, All India Institute of Medical Sciences, New Delhi, India
| | - Annette Bellar
- Department of Inflammation and Immunity, Lerner Research Institute, Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, Ohio, USA
| | - Saurabh Mishra
- Department of Inflammation and Immunity, Lerner Research Institute, Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, Ohio, USA
| | - Jinendiran Sekar
- Department of Inflammation and Immunity, Lerner Research Institute, Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, Ohio, USA
| | - Nicole Welch
- Department of Inflammation and Immunity, Lerner Research Institute, Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, Ohio, USA
| | - Srinivasan Dasarathy
- Department of Inflammation and Immunity, Lerner Research Institute, Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, Ohio, USA.
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Ng D, Pawling J, Dennis JW. Gene purging and the evolution of Neoave metabolism and longevity. J Biol Chem 2023; 299:105409. [PMID: 37918802 PMCID: PMC10722388 DOI: 10.1016/j.jbc.2023.105409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/19/2023] [Accepted: 10/25/2023] [Indexed: 11/04/2023] Open
Abstract
Maintenance of the proteasome requires oxidative phosphorylation (ATP) and mitigation of oxidative damage, in an increasingly dysfunctional relationship with aging. SLC3A2 plays a role on both sides of this dichotomy as an adaptor to SLC7A5, a transporter of branched-chain amino acids (BCAA: Leu, Ile, Val), and to SLC7A11, a cystine importer supplying cysteine to the synthesis of the antioxidant glutathione. Endurance in mammalian muscle depends in part on oxidation of BCAA; however, elevated serum levels are associated with insulin resistance and shortened lifespans. Intriguingly, the evolution of modern birds (Neoaves) has entailed the purging of genes including SLC3A2, SLC7A5, -7, -8, -10, and SLC1A4, -5, largely removing BCAA exchangers and their interacting Na+/Gln symporters in pursuit of improved energetics. Additional gene purging included mitochondrial BCAA aminotransferase (BCAT2), pointing to reduced oxidation of BCAA and increased hepatic conversion to triglycerides and glucose. Fat deposits are anhydrous and highly reduced, maximizing the fuel/weight ratio for prolonged flight, but fat accumulation in muscle cells of aging humans contributes to inflammation and senescence. Duplications of the bidirectional α-ketoacid transporters SLC16A3, SLC16A7, the cystine transporters SLC7A9, SLC7A11, and N-glycan branching enzymes MGAT4B, MGAT4C in Neoaves suggests a shift to the transport of deaminated essential amino acid, and stronger mitigation of oxidative stress supported by the galectin lattice. We suggest that Alfred Lotka's theory of natural selection as a maximum power organizer (PNAS 8:151,1922) made an unusually large contribution to Neoave evolution. Further molecular analysis of Neoaves may reveal novel rewiring with applications for human health and longevity.
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Affiliation(s)
- Deanna Ng
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Judy Pawling
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - James W Dennis
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto Ontario, Canada.
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Rosario FJ, Urschitz J, Powell TL, Brown TL, Jansson T. Overexpression of the LAT1 in primary human trophoblast cells increases the uptake of essential amino acids and activates mTOR signaling. Clin Sci (Lond) 2023; 137:1651-1664. [PMID: 37861075 DOI: 10.1042/cs20230490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 10/16/2023] [Accepted: 10/19/2023] [Indexed: 10/21/2023]
Abstract
The System L amino acid transporter, particularly the isoform Large Neutral Amino Acid Transporter Small Subunit 1 (LAT1) encoded by SLC7A5, is believed to mediate the transfer of essential amino acids in the human placenta. Placental System L amino acid transporter expression and activity is decreased in pregnancies complicated by IUGR and increased in fetal overgrowth. However, it remains unknown if changes in the expression of LAT1 are mechanistically linked to System L amino acid transport activity. Here, we combined overexpression approaches with protein analysis and functional studies in cultured primary human trophoblast (PHT) cells to test the hypothesis that SLC7A5 overexpression increases the uptake of essential amino acids and activates mTOR signaling in PHT cells. Overexpression of SLC7A5 resulted in a marked increase in protein expression of LAT1 in the PHT cells microvillous plasma membrane and System L amino acid transporter activity. Moreover, mTOR signaling was activated, and System A amino acid transporter activity increased following SLC7A5 overexpression, suggesting coordination of trophoblast amino transporter expression and activity to ensure balanced nutrient flux to the fetus. This is the first report showing that overexpression of LAT1 is sufficient to increase the uptake of essential amino acids in PHT cells, which activates mTOR, a master regulator of placental function. The decreased placental System L activity in human IUGR and the increased placental activity of this transporter system in some cases of fetal overgrowth may directly contribute to changes in fetal amino acid availability and altered fetal growth in these pregnancy complications.
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Affiliation(s)
- Fredrick J Rosario
- Department of Obstetrics and Gynecology, University of Colorado, Anschutz Medical Campus, Aurora, CO, U.S.A
| | - Johann Urschitz
- Institute for Biogenesis Research, University of Hawaii, Honolulu, HI, U.S.A
| | - Theresa L Powell
- Department of Obstetrics and Gynecology, University of Colorado, Anschutz Medical Campus, Aurora, CO, U.S.A
- Institute for Biogenesis Research, University of Hawaii, Honolulu, HI, U.S.A
| | - Thomas L Brown
- Section of Neonatology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, U.S.A
- Department of Neuroscience, Cell Biology, and Physiology, Wright State University Boonshoft School of Medicine, Dayton, OH, U.S.A
| | - Thomas Jansson
- Department of Obstetrics and Gynecology, University of Colorado, Anschutz Medical Campus, Aurora, CO, U.S.A
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Kahlhofer J, Teis D. The human LAT1-4F2hc (SLC7A5-SLC3A2) transporter complex: Physiological and pathophysiological implications. Basic Clin Pharmacol Toxicol 2023; 133:459-472. [PMID: 36460306 DOI: 10.1111/bcpt.13821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/24/2022] [Accepted: 11/28/2022] [Indexed: 12/04/2022]
Abstract
LAT1 and 4F2hc form a heterodimeric membrane protein complex, which functions as one of the best characterized amino acid transporters. Since LAT1-4F2hc is required for the efficient uptake of essential amino acids and hormones, it promotes cellular growth, in part, by stimulating mTORC1 (mechanistic target of rapamycin complex 1) signalling and by repressing the integrated stress response (ISR). Gain or loss of LAT1-4F2hc function is associated with cancer, diabetes, and immunological and neurological diseases. Hence, LAT1-4F2hc represents an attractive drug target for disease treatment. Specific targeting of LAT1-4F2hc will be facilitated by the increasingly detailed understanding of its molecular architecture, which provides important concepts for its function and regulation. Here, we summarize (i) structural insights that help to explain how LAT1 and 4F2hc assemble to transport amino acids across membranes, (ii) the role of LAT1-4F2hc in key metabolic signalling pathways, and (iii) how derailing these processes could contribute to diseases.
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Affiliation(s)
- Jennifer Kahlhofer
- Institute for Cell Biology, Biocenter, Medical University Innsbruck, Innsbruck, Austria
| | - David Teis
- Institute for Cell Biology, Biocenter, Medical University Innsbruck, Innsbruck, Austria
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Forteath C, Mordi I, Nisr R, Gutierrez-Lara EJ, Alqurashi N, Phair IR, Cameron AR, Beall C, Bahr I, Mohan M, Wong AKF, Dihoum A, Mohammad A, Palmer CNA, Lamont D, Sakamoto K, Viollet B, Foretz M, Lang CC, Rena G. Amino acid homeostasis is a target of metformin therapy. Mol Metab 2023; 74:101750. [PMID: 37302544 PMCID: PMC10328998 DOI: 10.1016/j.molmet.2023.101750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 04/04/2023] [Accepted: 06/05/2023] [Indexed: 06/13/2023] Open
Abstract
OBJECTIVE Unexplained changes in regulation of branched chain amino acids (BCAA) during diabetes therapy with metformin have been known for years. Here we have investigated mechanisms underlying this effect. METHODS We used cellular approaches, including single gene/protein measurements, as well as systems-level proteomics. Findings were then cross-validated with electronic health records and other data from human material. RESULTS In cell studies, we observed diminished uptake/incorporation of amino acids following metformin treatment of liver cells and cardiac myocytes. Supplementation of media with amino acids attenuated known effects of the drug, including on glucose production, providing a possible explanation for discrepancies between effective doses in vivo and in vitro observed in most studies. Data-Independent Acquisition proteomics identified that SNAT2, which mediates tertiary control of BCAA uptake, was the most strongly suppressed amino acid transporter in liver cells following metformin treatment. Other transporters were affected to a lesser extent. In humans, metformin attenuated increased risk of left ventricular hypertrophy due to the AA allele of KLF15, which is an inducer of BCAA catabolism. In plasma from a double-blind placebo-controlled trial in nondiabetic heart failure (trial registration: NCT00473876), metformin caused selective accumulation of plasma BCAA and glutamine, consistent with the effects in cells. CONCLUSIONS Metformin restricts tertiary control of BCAA cellular uptake. We conclude that modulation of amino acid homeostasis contributes to therapeutic actions of the drug.
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Affiliation(s)
- Calum Forteath
- Division of Cellular and Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, DD1 9SY, UK
| | - Ify Mordi
- Division of Molecular and Clinical Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, DD1 9SY, UK
| | - Raid Nisr
- Division of Cellular and Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, DD1 9SY, UK
| | - Erika J Gutierrez-Lara
- Division of Cellular and Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, DD1 9SY, UK
| | - Noor Alqurashi
- Division of Cellular and Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, DD1 9SY, UK
| | - Iain R Phair
- Division of Cellular and Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, DD1 9SY, UK
| | - Amy R Cameron
- Division of Cellular and Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, DD1 9SY, UK; Department of Clinical and Biomedical Sciences, Faculty of Health and Life Sciences, University of Exeter, RILD Building, Exeter, EX2 5DW, UK
| | - Craig Beall
- Department of Clinical and Biomedical Sciences, Faculty of Health and Life Sciences, University of Exeter, RILD Building, Exeter, EX2 5DW, UK
| | - Ibrahim Bahr
- Division of Cellular and Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, DD1 9SY, UK
| | - Mohapradeep Mohan
- Division of Molecular and Clinical Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, DD1 9SY, UK
| | - Aaron K F Wong
- Division of Molecular and Clinical Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, DD1 9SY, UK
| | - Adel Dihoum
- Division of Cellular and Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, DD1 9SY, UK; Division of Molecular and Clinical Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, DD1 9SY, UK
| | - Anwar Mohammad
- Public Health and Epidemiology Department, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Colin N A Palmer
- Division of Population Health and Genomics, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, DD1 9SY, UK
| | - Douglas Lamont
- Centre for Advanced Scientific Technologies, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Kei Sakamoto
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Benoit Viollet
- Université Paris Cité, CNRS, Inserm, Institut Cochin, Paris, 75014, France
| | - Marc Foretz
- Université Paris Cité, CNRS, Inserm, Institut Cochin, Paris, 75014, France
| | - Chim C Lang
- Division of Molecular and Clinical Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, DD1 9SY, UK.
| | - Graham Rena
- Division of Cellular and Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, DD1 9SY, UK.
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10
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Rivera CN, Smith CE, Draper LV, Ochoa GE, Watne RM, Wommack AJ, Vaughan RA. The Selective LAT1 Inhibitor JPH203 Enhances Mitochondrial Metabolism and Content in Insulin-Sensitive and Insulin-Resistant C2C12 Myotubes. Metabolites 2023; 13:766. [PMID: 37367923 DOI: 10.3390/metabo13060766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/09/2023] [Accepted: 06/13/2023] [Indexed: 06/28/2023] Open
Abstract
Population data have shown an association between higher circulating branched-chain amino acids (BCAA) and the severity of insulin resistance in people with diabetes. While several studies have assessed BCAA metabolism as a potential target for regulation, less attention has been paid to the role of L-type amino acid transporter 1 (LAT1), the primary transporter of BCAA in skeletal muscle. The aim of this study was to assess the impact of JPH203 (JPH), a LAT1 inhibitor, on myotube metabolism in both insulin-sensitive and insulin-resistant myotubes. C2C12 myotubes were treated with or without 1 μM or 2 μM JPH for 24 h with or without insulin resistance. Western blot and qRT-PCR were used to assess protein content and gene expression, respectively. Mitochondrial and glycolytic metabolism were measured via Seahorse Assay, and fluorescent staining was used to measure mitochondrial content. BCAA media content was quantified using liquid chromatography-mass spectrometry. JPH at 1 μM (but not 2 μM) increased mitochondrial metabolism and content without inducing changes in mRNA expression of transcripts associated with mitochondrial biogenesis or mitochondrial dynamics. Along with increased mitochondrial function, 1μM treatment also reduced extracellular leucine and valine. JPH at 2 μM reduced pAkt signaling and increased extracellular accumulation of isoleucine without inducing changes in BCAA metabolic genes. Collectively, JPH may increase mitochondrial function independent of the mitochondrial biogenic transcription pathway; however, high doses may reduce insulin signaling.
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Affiliation(s)
- Caroline N Rivera
- Department of Exercise Science, High Point University, High Point, NC 27268, USA
| | - Carly E Smith
- Department of Exercise Science, High Point University, High Point, NC 27268, USA
| | - Lillian V Draper
- Department of Exercise Science, High Point University, High Point, NC 27268, USA
| | - Gabriela E Ochoa
- Department of Exercise Science, High Point University, High Point, NC 27268, USA
| | - Rachel M Watne
- Department of Chemistry, High Point University, High Point, NC 27268, USA
| | - Andrew J Wommack
- Department of Chemistry, High Point University, High Point, NC 27268, USA
| | - Roger A Vaughan
- Department of Exercise Science, High Point University, High Point, NC 27268, USA
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11
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Rivera CN, Hinkle JS, Watne RM, Macgowan TC, Wommack AJ, Vaughan RA. PPAR β/ δ Agonism with GW501516 Increases Myotube PGC-1 α Content and Reduces BCAA Media Content Independent of Changes in BCAA Catabolic Enzyme Expression. PPAR Res 2023; 2023:4779199. [PMID: 37325367 PMCID: PMC10264138 DOI: 10.1155/2023/4779199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 05/01/2023] [Accepted: 05/17/2023] [Indexed: 06/17/2023] Open
Abstract
Background Type 2 diabetes is characterized by reduced insulin sensitivity, elevated blood metabolites, and reduced mitochondrial metabolism with reduced expression of genes governing metabolism such as peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α). PGC-1α regulates the expression of branched-chain amino acid (BCAA) metabolism, and thus, increased circulating BCAA in diabetics may be partially explained by reduced PGC-1α expression. PGC-1α functions in-part through interactions with peroxisome proliferator-activated receptor β/δ (PPARβ/δ). The present report examined the effects of the PPARβ/δ agonism on cell metabolism and related gene/protein expression of cultured myotubes, with a primary emphasis on determining the effects of GW on BCAA disposal and catabolic enzyme expression. Methods C2C12 myotubes were treated with GW501516 (GW) for up to 24 hours. Mitochondrial and glycolytic metabolism were measured via oxygen consumption and extracellular acidification rate, respectively. Metabolic gene and protein expression were assessed via quantitative real-time polymerase chain reaction (qRT-PCR) and western blot, respectively. Media BCAA content was assessed via liquid chromatography-mass spectrometry (LC/MS). Results GW significantly increased PGC-1α protein expression, mitochondrial content, and mitochondrial function. GW also significantly reduced BCAA content within culture media following 24-hour treatment; however, expression of BCAA catabolic enzymes/transporter was unchanged. Conclusion These data confirm the ability of GW to increase muscle PGC-1α content and decrease BCAA media content without affecting BCAA catabolic enzymes/transporter. These findings suggest heightened BCAA uptake (and possibly metabolism) may occur without substantial changes in the protein levels of related cell machinery.
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Affiliation(s)
- Caroline N. Rivera
- Department of Exercise Science, High Point University, High Point, NC, USA
| | - Jason S. Hinkle
- Department of Exercise Science, High Point University, High Point, NC, USA
| | - Rachel M. Watne
- Department of Chemistry, High Point University, High Point, NC, USA
| | | | | | - Roger A. Vaughan
- Department of Exercise Science, High Point University, High Point, NC, USA
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12
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Hou YC, Wu JM, Chen KY, Wu MH, Yang PJ, Lee PC, Chen PD, Yeh SL, Lin MT. Glutamine and leucine administration attenuates muscle atrophy in sepsis. Life Sci 2023; 314:121327. [PMID: 36584912 DOI: 10.1016/j.lfs.2022.121327] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/02/2022] [Accepted: 12/22/2022] [Indexed: 12/28/2022]
Abstract
AIMS This study investigated whether l-glutamine (Gln) and/or l-leucine (Leu) administration could attenuate muscle atrophy in a mouse model of cecal ligation and puncture (CLP)-induced sepsis. MATERIALS AND METHODS Septic mice were given a daily intraperitoneal injection of Gln, Leu, or Gln plus Leu, and mice were sacrificed on either day 1 or 4 after CLP. Blood and muscles were collected for analysis of amino acid contents and markers related to protein degradation, muscle regeneration, and protein synthesis. KEY FINDINGS Leu treatment alone increased both muscle mass and total muscle protein content on day 4 after CLP. Gln administration reduced muscular Gln contents on day 1 and enhanced plasma Gln levels on day 4. Higher plasma branched-chain amino acid (BCAA) abundances and lower muscular BCAA levels were observed in Leu-treated mice on day 4. Gln and Leu individually suppressed muscle expressions of the E3 ubiquitin ligase genes, Trim63 and Fbxo32, on day 4 after CLP. As to muscle expressions of myogenic genes, both Gln and Leu upregulated Myog expression on day 1, but Leu alone enhanced Myf5 gene expression, whereas Gln plus Leu increased MyoD and Myog expression levels on day 4. Akt/mammalian target of rapamycin (mTOR) signaling was only activated by Gln and Leu when individually administered. SIGNIFICANCE Gln and/or Leu administration reduces sepsis-induced muscle degradation and promotes myogenic gene expressions. Leu treatment alone had more-pronounced effects on maintaining muscle mass during sepsis. A combination of Gln and Leu failed to show synergistic effects on alleviating sepsis-induced muscle atrophy.
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Affiliation(s)
- Yu-Chen Hou
- Master Program in Food Safety, College of Nutrition, Taipei Medical University, Taipei, Taiwan; School of Food Safety, College of Nutrition, Taipei Medical University, Taipei, Taiwan; Nutrition Research Center, Taipei Medical University Hospital, Taipei, Taiwan
| | - Jin-Ming Wu
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Kuen-Yuan Chen
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ming-Hsun Wu
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Po-Jen Yang
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Po-Chu Lee
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Po-Da Chen
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Sung-Ling Yeh
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ming-Tsan Lin
- Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan.
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13
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Rivera CN, Watne RM, Brown ZA, Mitchell SA, Wommack AJ, Vaughan RA. Effect of AMPK activation and glucose availability on myotube LAT1 expression and BCAA utilization. Amino Acids 2023; 55:275-286. [PMID: 36547760 DOI: 10.1007/s00726-022-03224-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 12/01/2022] [Indexed: 12/24/2022]
Abstract
Those with insulin resistance often display increased circulating branched-chain amino acids (BCAA), which has been largely attributable to reduced BCAA catabolic capacity. Metabolic stimuli such as exercise activates AMP-activated kinase (AMPK), which promotes the metabolism of BCAA and induction/activation of BCAA catabolic enzymes. Though much attention has been paid to BCAA catabolic machinery, few studies have assessed the effect of AMPK activation on the predominant BCAA transporter, L-type amino acid transporter 1 (LAT1). This study assessed the effect of AMPK activation on LAT1 expression via common chemical AMPK activators in a cell model of skeletal muscle. C2C12 myotubes were treated with either 1 mM AICAR, 1 mM Metformin, or filter-sterilized water (control) for 24 h with either low- (5 mM) or high-glucose (25 mM) media. LAT1 and pAMPK protein content were measured via western blot. BCAA media content was measured using liquid chromatography-mass spectrometry. AICAR treatment significantly increased pAMPK and reduced LAT1 expression. Collectively, pAMPK and LAT1 displayed a significant inverse relationship independent of glucose levels. During low-glucose experiments, AICAR-treated cells had higher BCAA media content compared to other groups, and an inverse relationship between LAT1 and BCAA media content was observed, however, these effects were not consistently observed during high-glucose conditions. Further investigation with AICAR with and without concurrent LAT1 inhibition (via JPH203) also revealed reduced BCAA utilization in AICAR-treated cells regardless of LAT1 inhibition (which also independently reduced BCAA utilization). pAMPK activation via AICAR (but not Metformin) may reduce LAT1 expression and BCAA uptake in a glucose-dependent manner.
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Affiliation(s)
- Caroline N Rivera
- Department of Exercise Science, High Point University, One University Parkway, High Point, NC, 27268, USA
| | - Rachel M Watne
- Department of Chemistry, High Point University, One University Parkway, High Point, NC, 27268, USA
| | - Zoe A Brown
- Department of Chemistry, High Point University, One University Parkway, High Point, NC, 27268, USA
| | - Samantha A Mitchell
- Department of Chemistry, High Point University, One University Parkway, High Point, NC, 27268, USA
| | - Andrew J Wommack
- Department of Chemistry, High Point University, One University Parkway, High Point, NC, 27268, USA
| | - Roger A Vaughan
- Department of Exercise Science, High Point University, One University Parkway, High Point, NC, 27268, USA.
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14
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Bao L, Fu L, Su Y, Chen Z, Peng Z, Sun L, Gonzalez FJ, Wu C, Zhang H, Shi B, Shi YB. Amino acid transporter SLC7A5 regulates Paneth cell function to affect the intestinal inflammatory response. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.24.524966. [PMID: 36789439 PMCID: PMC9928054 DOI: 10.1101/2023.01.24.524966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The intestine is critical for not only processing and resorbing nutrients but also protecting the organism from the environment. These functions are mainly carried out by the epithelium, which is constantly being self-renewed. Many genes and pathways can influence intestinal epithelial cell proliferation. Among them is mTORC1, whose activation increases cell proliferation. Here, we report the first intestinal epithelial cell-specific knockout ( ΔIEC ) of an amino acid transporter capable of activating mTORC1. We show that the transporter, SLC7A5, is highly expressed in mouse intestinal crypt and Slc7a5 ΔIEC reduces mTORC1 signaling. Surprisingly, Slc7a5 ΔIEC mice have increased cell proliferation but reduced secretory cells, particularly mature Paneth cells. scRNA-seq and electron microscopic analyses revealed dedifferentiation of Paneth cells in Slc7a5 ΔIEC mice, leading to markedly reduced secretory granules with little effect on Paneth cell number. We further show that Slc7a5 ΔIEC mice are prone to experimental colitis. Thus, SLC7A5 regulates secretory cell differentiation to affect stem cell niche and/or inflammatory response to regulate cell proliferation.
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15
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Rivera CN, Kamer MM, Rivera ME, Watne RM, Macgowan TC, Wommack AJ, Vaughan RA. Insulin resistance promotes extracellular BCAA accumulation without altering LAT1 content, independent of prior BCAA treatment in a myotube model of skeletal muscle. Mol Cell Endocrinol 2023; 559:111800. [PMID: 36270542 DOI: 10.1016/j.mce.2022.111800] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/13/2022] [Accepted: 10/14/2022] [Indexed: 11/17/2022]
Abstract
PURPOSE Type 2 diabetes is characterized by reduced insulin sensitivity which correlates with increased circulating BCAA. These experiments investigated the effects of insulin resistance with and without excess BCAA on myotube insulin sensitivity and L-type amino acid transporter-1 (LAT1). METHODS C2C12 myotubes were treated with or without excess BCAA for 1 or 6 days, both with and without insulin resistance. Western blot was used to assess insulin sensitivity and LAT1 content. Liquid chromatography-mass spectrometry was used to evaluate BCAA media content. RESULTS Insulin resistance was associated with significantly increased extracellular BCAA accumulation independent of LAT1 content. Conversely, prior BCAA treatment was not associated with extracellular BCAA accumulation regardless of level of insulin sensitivity. CONCLUSION These data suggest insulin resistance, but not BCAA treatment, promotes extracellular BCAA accumulation independent of changes in LAT1 content, implicating insulin resistance as a causal agent of extracellular BCAA accumulation.
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Affiliation(s)
- Caroline N Rivera
- Department of Exercise Science, High Point University, High Point, NC, USA.
| | - Madison M Kamer
- Department of Exercise Science, High Point University, High Point, NC, USA.
| | - Madison E Rivera
- Department of Exercise Science, High Point University, High Point, NC, USA.
| | - Rachel M Watne
- Department of Chemistry, High Point University, High Point, NC, USA.
| | - Trent C Macgowan
- Department of Chemistry, High Point University, High Point, NC, USA.
| | - Andrew J Wommack
- Department of Chemistry, High Point University, High Point, NC, USA.
| | - Roger A Vaughan
- Department of Exercise Science, High Point University, High Point, NC, USA.
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16
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Bouthelier A, Fernández-Arroyo L, Mesa-Ciller C, Cibrian D, Martín-Cófreces NB, Castillo-González R, Calero M, Herráez-Aguilar D, Guajardo-Grence A, Pacheco AM, Marcos-Jiménez A, Quiroga B, Morado M, Monroy F, Muñoz-Calleja C, Sánchez-Madrid F, Urrutia AA, Aragonés J. Erythroid SLC7A5/SLC3A2 amino acid carrier controls red blood cell size and maturation. iScience 2022; 26:105739. [PMID: 36582828 PMCID: PMC9792907 DOI: 10.1016/j.isci.2022.105739] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 10/31/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022] Open
Abstract
Inhibition of the heterodimeric amino acid carrier SLC7A5/SLC3A2 (LAT1/CD98) has been widely studied in tumor biology but its role in physiological conditions remains largely unknown. Here we show that the SLC7A5/SLC3A2 heterodimer is constitutively present at different stages of erythroid differentiation but absent in mature erythrocytes. Administration of erythropoietin (EPO) further induces SLC7A5/SLC3A2 expression in circulating reticulocytes, as it also occurs in anemic conditions. Although Slc7a5 gene inactivation in the erythrocyte lineage does not compromise the total number of circulating red blood cells (RBCs), their size and hemoglobin content are significantly reduced accompanied by a diminished erythroblast mTORC1 activity. Furthermore circulating Slc7a5-deficient reticulocytes are characterized by lower transferrin receptor (CD71) expression as well as mitochondrial activity, suggesting a premature transition to mature RBCs. These data reveal that SLC7A5/SLC3A2 ensures adequate maturation of reticulocytes as well as the proper size and hemoglobin content of circulating RBCs.
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Affiliation(s)
- Antonio Bouthelier
- Research Unit, Hospital of Santa Cristina, Research Institute Princesa (IP), Autonomous University of Madrid, 28009 Madrid, Spain
| | - Lucía Fernández-Arroyo
- Research Unit, Hospital of Santa Cristina, Research Institute Princesa (IP), Autonomous University of Madrid, 28009 Madrid, Spain
| | - Claudia Mesa-Ciller
- Research Unit, Hospital of Santa Cristina, Research Institute Princesa (IP), Autonomous University of Madrid, 28009 Madrid, Spain
| | - Danay Cibrian
- Immunology Department, Hospital de la Princesa, Instituto Investigación Sanitaria Princesa, Universidad Autónoma de Madrid, Madrid, Spain,Department of Vascular Biology and Inflammation, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Noa Beatriz Martín-Cófreces
- Immunology Department, Hospital de la Princesa, Instituto Investigación Sanitaria Princesa, Universidad Autónoma de Madrid, Madrid, Spain,Department of Vascular Biology and Inflammation, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Raquel Castillo-González
- Immunology Department, Hospital de la Princesa, Instituto Investigación Sanitaria Princesa, Universidad Autónoma de Madrid, Madrid, Spain,Department of Vascular Biology and Inflammation, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain,Pathology Anatomy Department, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, Spain
| | - Macarena Calero
- Departamento de Química Física, Universidad Complutense de Madrid, Ciudad Universitaria s/n, Madrid, Spain,Translational Biophysics. Instituto de Investigación Sanitaria Hospital Doce de Octubre (Imas12), Madrid, Spain
| | - Diego Herráez-Aguilar
- Facultad de Ciencias Experimentales, Universidad Francisco de Vitoria, Ctra. Pozuelo-Majadahonda Km 1,800, 28223, Pozuelo de Alarcón, Madrid, Spain
| | - Andrea Guajardo-Grence
- Research Unit, Hospital of Santa Cristina, Research Institute Princesa (IP), Autonomous University of Madrid, 28009 Madrid, Spain
| | - Ana María Pacheco
- Research Unit, Hospital of Santa Cristina, Research Institute Princesa (IP), Autonomous University of Madrid, 28009 Madrid, Spain
| | - Ana Marcos-Jiménez
- Immunology Department, Hospital de la Princesa, Instituto Investigación Sanitaria Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Borja Quiroga
- Nephrology Department, Hospital de la Princesa, Instituto Investigación Sanitaria Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Marta Morado
- Hematology Department, Hospital Universitario La Paz, Madrid, Spain
| | - Francisco Monroy
- Departamento de Química Física, Universidad Complutense de Madrid, Ciudad Universitaria s/n, Madrid, Spain,Translational Biophysics. Instituto de Investigación Sanitaria Hospital Doce de Octubre (Imas12), Madrid, Spain
| | - Cecilia Muñoz-Calleja
- Immunology Department, Hospital de la Princesa, Instituto Investigación Sanitaria Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Francisco Sánchez-Madrid
- Immunology Department, Hospital de la Princesa, Instituto Investigación Sanitaria Princesa, Universidad Autónoma de Madrid, Madrid, Spain,Nephrology Department, Hospital de la Princesa, Instituto Investigación Sanitaria Princesa, Universidad Autónoma de Madrid, Madrid, Spain,CIBER de Enfermedades Cardiovasculares, Carlos III Health Institute, Madrid, Spain
| | - Andrés A. Urrutia
- Research Unit, Hospital of Santa Cristina, Research Institute Princesa (IP), Autonomous University of Madrid, 28009 Madrid, Spain
| | - Julián Aragonés
- Research Unit, Hospital of Santa Cristina, Research Institute Princesa (IP), Autonomous University of Madrid, 28009 Madrid, Spain,CIBER de Enfermedades Cardiovasculares, Carlos III Health Institute, Madrid, Spain,Corresponding author
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17
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Thyroid Hormone Transporters in Pregnancy and Fetal Development. Int J Mol Sci 2022; 23:ijms232315113. [PMID: 36499435 PMCID: PMC9737226 DOI: 10.3390/ijms232315113] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 11/25/2022] [Accepted: 11/26/2022] [Indexed: 12/05/2022] Open
Abstract
Thyroid hormone is essential for fetal (brain) development. Plasma membrane transporters control the intracellular bioavailability of thyroid hormone. In the past few decades, 15 human thyroid hormone transporters have been identified, and among them, mutations in monocarboxylate transporter (MCT)8 and organic anion transporting peptide (OATP)1C1 are associated with clinical phenotypes. Different animal and human models have been employed to unravel the (patho)-physiological role of thyroid hormone transporters. However, most studies on thyroid hormone transporters focus on postnatal development. This review summarizes the research on the thyroid hormone transporters in pregnancy and fetal development, including their substrate preference, expression and tissue distribution, and physiological and pathophysiological role in thyroid homeostasis and clinical disorders. As the fetus depends on the maternal thyroid hormone supply, especially during the first half of pregnancy, the review also elaborates on thyroid hormone transport across the human placental barrier. Future studies may reveal how the different transporters contribute to thyroid hormone homeostasis in fetal tissues to properly facilitate development. Employing state-of-the-art human models will enable a better understanding of their roles in thyroid hormone homeostasis.
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18
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Tinline-Goodfellow CT, Lees MJ, Hodson N. The skeletal muscle fiber periphery: A nexus of mTOR-related anabolism. SPORTS MEDICINE AND HEALTH SCIENCE 2022; 5:10-19. [PMID: 36994172 PMCID: PMC10040390 DOI: 10.1016/j.smhs.2022.11.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 11/16/2022] [Accepted: 11/23/2022] [Indexed: 12/02/2022] Open
Abstract
Skeletal muscle anabolism is driven by numerous stimuli such as growth factors, nutrients (i.e., amino acids, glucose), and mechanical stress. These stimuli are integrated by the mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) signal transduction cascade. In recent years, work from our laboratory and elsewhere has sought to unravel the molecular mechanisms underpinning the mTOR-related activation of muscle protein synthesis (MPS), as well as the spatial regulation of these mechanisms within the skeletal muscle cell. These studies have suggested that the skeletal muscle fiber periphery is a region of central importance in anabolism (i.e., growth/MPS). Indeed, the fiber periphery is replete with the substrates, molecular machinery, and translational apparatus necessary to facilitate MPS. This review provides a summary of the mechanisms underpinning the mTOR-associated activation of MPS from cell, rodent, and human studies. It also presents an overview of the spatial regulation of mTORC1 in response to anabolic stimuli and outlines the factors that distinguish the periphery of the cell as a highly notable region of skeletal muscle for the induction of MPS. Future research should seek to further explore the nutrient-induced activation of mTORC1 at the periphery of skeletal muscle fibers.
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Affiliation(s)
| | - Matthew J. Lees
- Faculty of Kinesiology and Physical Education, University of Toronto, Canada
| | - Nathan Hodson
- Faculty of Kinesiology and Physical Education, University of Toronto, Canada
- Institute of Sport, Manchester Metropolitan University, Manchester, United Kingdom
- Department of Sport and Exercise Sciences, Manchester Metropolitan University, Manchester, United Kingdom
- Corresponding author. Faculty of Kinesiology and Physical Education, University of Toronto, Canada.
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19
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D'Hulst G, Masschelein E, De Bock K. Resistance exercise enhances long-term mTORC1 sensitivity to leucine. Mol Metab 2022; 66:101615. [PMID: 36252815 PMCID: PMC9626937 DOI: 10.1016/j.molmet.2022.101615] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 10/07/2022] [Accepted: 10/12/2022] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE Exercise enhances the sensitivity of mammalian target of rapamycin complex 1 (mTORC1) to amino acids, in particular leucine. How long this enhanced sensitivity lasts, and which mechanisms control enhanced leucine-mediated mTORC1 activation following exercise is currently unknown. METHODS C57BL/6J mice were exercised for one night in a resistance-braked running wheel after a 12-day acclimatization period. Mice were gavaged with a submaximal dose of l-leucine or saline acutely or 48 h after exercise cessation, following 3 h food withdrawal. Muscles were excised 30 min after leucine administration. To study the contribution of mTORC1, we repeated those experiments but blocked mTORC1 activation using rapamycin immediately before the overnight running bout and one hour before the first dose of leucine. mTORC1 signaling, muscle protein synthesis and amino acid sensing machinery were assessed using immunoblot and qPCR. Leucine uptake was measured using L-[14C(U)]-leucine tracer labeling. RESULTS When compared to sedentary conditions, leucine supplementation more potently activated mTORC1 and protein synthesis in acutely exercised muscle. This effect was observed in m. soleus but not in m. tibialis anterior nor m. plantaris. The synergistic effect in m. soleus was long-lasting as key downstream markers of mTORC1 as well as protein synthesis remained higher when leucine was administered 48 h after exercise. We found that exercise enhanced the expression of amino acid transporters and promoted uptake of leucine into the muscle, leading to higher free intramuscular leucine levels. This coincided with increased expression of activating transcription factor 4 (ATF4), a main transcriptional regulator of amino acid uptake and metabolism, and downstream activation of amino acid genes as well as leucyl-tRNA synthetase (LARS), a putative leucine sensor. Finally, blocking mTORC1 using rapamycin did not reduce expression and activation of ATF4, suggesting that the latter does not act downstream of mTORC1. Rather, we found a robust increase in eukaryotic initiation factor 2α (eIF2α) phosphorylation, suggesting that the integrated stress response pathway, rather than exercise-induced mTORC1 activation, drives long-term ATF4 expression in skeletal muscle after exercise. CONCLUSIONS The enhanced sensitivity of mTORC1 to leucine is maintained at least 48 h after exercise. This shows that the anabolic window of opportunity for protein ingestion is not restricted to the first hours immediately following exercise. Increased mTORC1 sensitivity to leucine coincided with enhanced leucine influx into muscle and higher expression of genes involved in leucine sensing and amino acid metabolism. Also, exercise induced an increase in ATF4 protein expression. Altogether, these data suggest that muscular contractions switch on a coordinated program to enhance amino acid uptake as well as intramuscular sensing of key amino acids involved in mTORC1 activation and the stimulation of muscle protein synthesis.
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Affiliation(s)
- Gommaar D'Hulst
- Laboratory of Exercise and Health, Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH) Zurich, Zürich, Switzerland
| | - Evi Masschelein
- Laboratory of Exercise and Health, Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH) Zurich, Zürich, Switzerland
| | - Katrien De Bock
- Laboratory of Exercise and Health, Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH) Zurich, Zürich, Switzerland.
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20
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Iwahashi S, Lyu J, Tokumura K, Osumi R, Hiraiwa M, Kubo T, Horie T, Demura S, Kawakami N, Saito T, Park G, Fukasawa K, Iezaki T, Suzuki A, Tomizawa A, Ochi H, Hojo H, Ohba S, Hinoi E. Conditional inactivation of the L-type amino acid transporter LAT1 in chondrocytes models idiopathic scoliosis in mice. J Cell Physiol 2022; 237:4292-4302. [PMID: 36161979 DOI: 10.1002/jcp.30883] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 08/30/2022] [Accepted: 09/05/2022] [Indexed: 11/08/2022]
Abstract
Scoliosis, usually diagnosed in childhood and early adolescence, is an abnormal lateral curvature of the spine. L-type amino acid transporter 1 (LAT1), encoded by solute carrier transporter 7a5 (Slc7a5), plays a crucial role in amino acid sensing and signaling in specific cell types. We previously demonstrated the pivotal role of LAT1 on bone homeostasis in mice, and the expression of LAT1/SLC7A5 in vertebral cartilage of pediatric scoliosis patients; however, its role in chondrocytes on spinal homeostasis and implications regarding the underlying mechanisms during the onset and progression of scoliosis, remain unknown. Here, we identified LAT1 in mouse chondrocytes as an important regulator of postnatal spinal homeostasis. Conditional inactivation of LAT1 in chondrocytes resulted in a postnatal-onset severe thoracic scoliosis at the early adolescent stage with normal embryonic spinal development. Histological analyses revealed that Slc7a5 deletion in chondrocytes led to general disorganization of chondrocytes in the vertebral growth plate, along with an increase in apoptosis and a decrease in cell proliferation. Furthermore, loss of Slc7a5 in chondrocytes activated the general amino acid control (GAAC) pathway but inactivated the mechanistic target of rapamycin complex 1 (mTORC1) pathway in the vertebrae. The spinal deformity in Slc7a5-deficient mice was corrected by genetic inactivation of the GAAC pathway, but not by genetic activation of the mTORC1 pathway. These findings suggest that the LAT1-GAAC pathway in chondrocytes plays a critical role in the maintenance of proper spinal homeostasis by modulating cell proliferation and survivability.
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Affiliation(s)
- Sayuki Iwahashi
- Department of Bioactive Molecules, Pharmacology, Gifu Pharmaceutical University, Gifu, Japan
| | - Jiajun Lyu
- Department of Bioactive Molecules, Pharmacology, Gifu Pharmaceutical University, Gifu, Japan
| | - Kazuya Tokumura
- Department of Bioactive Molecules, Pharmacology, Gifu Pharmaceutical University, Gifu, Japan
| | - Ryoma Osumi
- Department of Bioactive Molecules, Pharmacology, Gifu Pharmaceutical University, Gifu, Japan
| | - Manami Hiraiwa
- Department of Bioactive Molecules, Pharmacology, Gifu Pharmaceutical University, Gifu, Japan
| | - Takuya Kubo
- Department of Bioactive Molecules, Pharmacology, Gifu Pharmaceutical University, Gifu, Japan
| | - Tetsuhiro Horie
- Department of Bioactive Molecules, Pharmacology, Gifu Pharmaceutical University, Gifu, Japan
| | - Satoru Demura
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Noriaki Kawakami
- Department of Orthopaedic Surgery, Ichinomiya Nishi Hospital, Ichinomiya, Japan
| | - Taku Saito
- Sensory and Motor System Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Gyujin Park
- Department of Bioactive Molecules, Pharmacology, Gifu Pharmaceutical University, Gifu, Japan
| | - Kazuya Fukasawa
- Department of Bioactive Molecules, Pharmacology, Gifu Pharmaceutical University, Gifu, Japan
| | - Takashi Iezaki
- Department of Bioactive Molecules, Pharmacology, Gifu Pharmaceutical University, Gifu, Japan
| | - Akane Suzuki
- Department of Bioactive Molecules, Pharmacology, Gifu Pharmaceutical University, Gifu, Japan
| | - Akane Tomizawa
- Department of Bioactive Molecules, Pharmacology, Gifu Pharmaceutical University, Gifu, Japan
| | - Hiroki Ochi
- Department of Rehabilitation for Motor Functions, Research Institute, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Saitama, Japan
| | - Hironori Hojo
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Shinsuke Ohba
- Department of Cell Biology, Institute of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Eiichi Hinoi
- Department of Bioactive Molecules, Pharmacology, Gifu Pharmaceutical University, Gifu, Japan.,United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu, Japan
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21
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Collao N, Akohene-Mensah P, Nallabelli J, Binet ER, Askarian A, Lloyd J, Niemiro GM, Beals JW, van Vliet S, Rajgara R, Saleh A, Wiper-Bergeron N, Paluska SA, Burd NA, De Lisio M. The Role of L-type Amino Acid Transporter 1 (Slc7a5) During In Vitro Myogenesis. Am J Physiol Cell Physiol 2022; 323:C595-C605. [PMID: 35848618 DOI: 10.1152/ajpcell.00162.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Satellite cells are required for muscle regeneration, remodeling, and repair through their activation, proliferation, and differentiation; however, how dietary factors regulate this process remains poorly understood. The L-Type amino acid transporter 1 (LAT1) transports amino acids, such as leucine, into mature myofibers, which then stimulates protein synthesis and anabolic signaling. However, whether LAT1 is expressed on myoblasts and is involved in regulating myogenesis is unknown. The aim of this study was to characterize the expression and functional relevance of LAT1 during different stages of myogenesis and in response to growth and atrophic conditions in vitro. We determined that LAT1 is expressed by C2C12 and human primary myoblasts, and its gene expression is lower during differentiation (p<0.05). Pharmacological inhibition and genetic knockdown of LAT1 impaired myoblast viability, differentiation, and fusion (all p<0.05). LAT1 protein content in C2C12 myoblasts was not significantly altered in response to different leucine concentrations in cell culture media or in two in vitro atrophy models. However, LAT1 content was decreased in myotubes under atrophic conditions in vitro (p<0.05). These findings indicate that LAT1 is stable throughout myogenesis and in response to several in vitro conditions that induce muscle remodeling. Further, amino acid transport through LAT1 is required for normal myogenesis in vitro.
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Affiliation(s)
- Nicolas Collao
- School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada
| | | | - Julian Nallabelli
- Departments of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Emileigh R Binet
- School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada
| | - Ali Askarian
- School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada
| | - Jessica Lloyd
- School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada
| | - Grace M Niemiro
- Departments of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Joseph W Beals
- Departments of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Stephan van Vliet
- Departments of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Rashida Rajgara
- Department of Cellular and Molecular Medicine and Centre on Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
| | - Aisha Saleh
- Department of Cellular and Molecular Medicine and Centre on Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
| | - Nadine Wiper-Bergeron
- Department of Cellular and Molecular Medicine and Centre on Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
| | - Scott A Paluska
- Departments of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Nicholas A Burd
- Departments of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Michael De Lisio
- School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada.,Departments of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States.,Department of Cellular and Molecular Medicine and Centre on Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
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22
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Khavinson V, Linkova N, Kozhevnikova E, Dyatlova A, Petukhov M. Transport of Biologically Active Ultrashort Peptides Using POT and LAT Carriers. Int J Mol Sci 2022; 23:ijms23147733. [PMID: 35887081 PMCID: PMC9323678 DOI: 10.3390/ijms23147733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 01/27/2023] Open
Abstract
Ultrashort peptides (USPs), consisting of 2–7 amino-acid residues, are a group of signaling molecules that regulate gene expression and protein synthesis under normal conditions in various diseases and ageing. USPs serve as a basis for the development of drugs with a targeted mechanism of action. The purpose of this review is to systematize the available data on USP transport involving POT and LAT transporters in various organs and tissues under normal, pathological and ageing conditions. The carriers of the POT family (PEPT1, PEPT2, PHT1, PHT2) transport predominantly di- and tripeptides into the cell. Methods of molecular modeling and physicochemistry have demonstrated the ability of LAT1 to transfer not only amino acids but also some di- and tripeptides into the cell and out of it. LAT1 and 2 are involved in the regulation of the antioxidant, endocrine, immune and nervous systems’ functions. Analysis of the above data allows us to conclude that, depending on their structure, di- and tripeptides can be transported into the cells of various tissues by POT and LAT transporters. This mechanism is likely to underlie the tissue specificity of peptides, their geroprotective action and effectiveness in the case of neuroimmunoendocrine system disorders.
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Affiliation(s)
- Vladimir Khavinson
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (N.L.); (E.K.); (A.D.)
- Group of Peptide Regulation of Aging, Pavlov Institute of Physiology of Russian Academy of Sciences, 199034 Saint Petersburg, Russia
- Correspondence: or ; Tel.: +7-(921)-9110800
| | - Natalia Linkova
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (N.L.); (E.K.); (A.D.)
- The Laboratory “Problems of Aging”, Belgorod National Research University, 308015 Belgorod, Russia
| | - Ekaterina Kozhevnikova
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (N.L.); (E.K.); (A.D.)
| | - Anastasiia Dyatlova
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (N.L.); (E.K.); (A.D.)
| | - Mikhael Petukhov
- Petersburg Nuclear Physics Institute Named after B.P. Konstantinov, NRC “Kurchatov Institute”, 188300 Gatchina, Russia;
- Peter the Great St. Petersburg Group of Biophysics, Higher Engineering and Technical School, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia
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23
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Physiological responses and adaptations to high methane production in Japanese Black cattle. Sci Rep 2022; 12:11154. [PMID: 35778422 PMCID: PMC9249741 DOI: 10.1038/s41598-022-15146-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 06/20/2022] [Indexed: 12/02/2022] Open
Abstract
In this study, using enteric methane emissions, we investigated the metabolic characteristics of Japanese Black cattle. Their methane emissions were measured at early (age 13 months), middle (20 months), and late fattening phases (28 months). Cattle with the highest and lowest methane emissions were selected based on the residual methane emission values, and their liver transcriptome, blood metabolites, hormones, and rumen fermentation characteristics were analyzed. Blood β-hydroxybutyric acid and insulin levels were high, whereas blood amino acid levels were low in cattle with high methane emissions. Further, propionate and butyrate levels differed depending on the enteric methane emissions. Hepatic genes, such as SERPINI2, SLC7A5, ATP6, and RRAD, which were related to amino acid transport and glucose metabolism, were upregulated or downregulated during the late fattening phase. The above mentioned metabolites and liver transcriptomes could be used to evaluate enteric methanogenesis in Japanese Black cattle.
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24
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Ong YT, Andrade J, Armbruster M, Shi C, Castro M, Costa ASH, Sugino T, Eelen G, Zimmermann B, Wilhelm K, Lim J, Watanabe S, Guenther S, Schneider A, Zanconato F, Kaulich M, Pan D, Braun T, Gerhardt H, Efeyan A, Carmeliet P, Piccolo S, Grosso AR, Potente M. A YAP/TAZ-TEAD signalling module links endothelial nutrient acquisition to angiogenic growth. Nat Metab 2022; 4:672-682. [PMID: 35726026 PMCID: PMC9236904 DOI: 10.1038/s42255-022-00584-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 05/13/2022] [Indexed: 12/13/2022]
Abstract
Angiogenesis, the process by which endothelial cells (ECs) form new blood vessels from existing ones, is intimately linked to the tissue's metabolic milieu and often occurs at nutrient-deficient sites. However, ECs rely on sufficient metabolic resources to support growth and proliferation. How endothelial nutrient acquisition and usage are regulated is unknown. Here we show that these processes are instructed by Yes-associated protein 1 (YAP)/WW domain-containing transcription regulator 1 (WWTR1/TAZ)-transcriptional enhanced associate domain (TEAD): a transcriptional module whose function is highly responsive to changes in the tissue environment. ECs lacking YAP/TAZ or their transcriptional partners, TEAD1, 2 and 4 fail to divide, resulting in stunted vascular growth in mice. Conversely, activation of TAZ, the more abundant paralogue in ECs, boosts proliferation, leading to vascular hyperplasia. We find that YAP/TAZ promote angiogenesis by fuelling nutrient-dependent mTORC1 signalling. By orchestrating the transcription of a repertoire of cell-surface transporters, including the large neutral amino acid transporter SLC7A5, YAP/TAZ-TEAD stimulate the import of amino acids and other essential nutrients, thereby enabling mTORC1 activation. Dissociating mTORC1 from these nutrient inputs-elicited by the loss of Rag GTPases-inhibits mTORC1 activity and prevents YAP/TAZ-dependent vascular growth. Together, these findings define a pivotal role for YAP/TAZ-TEAD in controlling endothelial mTORC1 and illustrate the essentiality of coordinated nutrient fluxes in the vasculature.
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Affiliation(s)
- Yu Ting Ong
- Angiogenesis & Metabolism Laboratory, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Jorge Andrade
- Angiogenesis & Metabolism Laboratory, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
- Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Max Armbruster
- Angiogenesis & Metabolism Laboratory, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Chenyue Shi
- Angiogenesis & Metabolism Laboratory, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Marco Castro
- Angiogenesis & Metabolism Laboratory, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
- Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Ana S H Costa
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Toshiya Sugino
- Angiogenesis & Metabolism Laboratory, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Guy Eelen
- Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, and Department of Oncology and Leuven Cancer Institute, VIB and KU Leuven, Leuven, Belgium
| | - Barbara Zimmermann
- Angiogenesis & Metabolism Laboratory, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Kerstin Wilhelm
- Angiogenesis & Metabolism Laboratory, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Joseph Lim
- Angiogenesis & Metabolism Laboratory, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
- Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Shuichi Watanabe
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Stefan Guenther
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Andre Schneider
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Francesca Zanconato
- Department of Molecular Medicine, University of Padua School of Medicine, Padua, Italy
| | - Manuel Kaulich
- Institute of Biochemistry II, Goethe University, Frankfurt (Main), Germany
| | - Duojia Pan
- Department of Physiology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Thomas Braun
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Holger Gerhardt
- Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
- Integrative Vascular Biology Laboratory, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- DZHK (German Center for Cardiovascular Research), partner site Berlin, Berlin, Germany
- Vascular Patterning Laboratory, Center for Cancer Biology, VIB and KU Leuven, Leuven, Belgium
| | - Alejo Efeyan
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre, Madrid, Spain
| | - Peter Carmeliet
- Laboratory of Angiogenesis and Vascular Metabolism, Center for Cancer Biology, and Department of Oncology and Leuven Cancer Institute, VIB and KU Leuven, Leuven, Belgium
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
- Laboratory of Angiogenesis and Vascular Heterogeneity, Department of Biomedicine, Aarhus, Denmark
| | - Stefano Piccolo
- Department of Molecular Medicine, University of Padua School of Medicine, Padua, Italy
- IFOM-ETS, the AIRC Institute of Molecular Oncology, Milan, Italy
| | - Ana Rita Grosso
- UCIBIO - Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Michael Potente
- Angiogenesis & Metabolism Laboratory, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.
- Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany.
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.
- DZHK (German Center for Cardiovascular Research), partner site Berlin, Berlin, Germany.
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25
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Nakai N, Iida N, Kitai S, Shimomura Y, Kitaura Y, Higashida K. BDK knockout skeletal muscle satellite cells exhibit enhanced protein translation initiation signal in response to BCAA in vitro. Biosci Biotechnol Biochem 2022; 86:610-617. [PMID: 35108367 DOI: 10.1093/bbb/zbac021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 01/27/2022] [Indexed: 11/13/2022]
Abstract
We examined the effects of branched-chain amino acids (BCAAs) and electrical pulse stimulation (EPS) on the mTORC1 pathway in muscle satellite cells (MSCs) isolated from branched-chain α-keto acid dehydrogenase kinase (BDK) knockout (KO) mice in vitro. MSCs were isolated from BDK KO and wild-type (WT) mice, proliferated, and differentiated into myotubes. BCAA stimulation increased the phosphorylation of p70 S6 kinase (p70S6K), a marker of protein translation initiation, in MSCs from WT and BDK KO mice, but the rate of the increase was higher in MSCs isolated from BDK KO mice. Contrarily, there was no difference in the increase in p70S6K phosphorylation by EPS. Acute BDK knockdown in MSCs from WT mice using shRNA decreased p70S6K phosphorylation in response to BCAA stimulation. Collectively, the susceptibility of mTORC1 to BCAA stimulation was elevated by chronic, but not acute, enhancement of BCAA catabolism.
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Affiliation(s)
- Naoya Nakai
- Department of Nutrition, University of Shiga Prefecture, Hikone, Shiga, Japan
| | - Noriko Iida
- Department of Nutrition, University of Shiga Prefecture, Hikone, Shiga, Japan
| | - Saki Kitai
- Department of Nutrition, University of Shiga Prefecture, Hikone, Shiga, Japan
| | - Yoshiharu Shimomura
- Department of Food and Nutritional Sciences, College of Bioscience and Biotechnology, Chubu University, Kasugai, Aichi, Japan
| | - Yasuyuki Kitaura
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Kazuhiko Higashida
- Department of Nutrition, University of Shiga Prefecture, Hikone, Shiga, Japan
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26
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Hagen CM, Roth E, Graf TR, Verrey F, Graf R, Gupta A, Pellegrini G, Poncet N, Camargo SMR. Loss of LAT1 sex-dependently delays recovery after caerulein-induced acute pancreatitis. World J Gastroenterol 2022; 28:1024-1054. [PMID: 35431492 PMCID: PMC8968515 DOI: 10.3748/wjg.v28.i10.1024] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 10/08/2021] [Accepted: 01/26/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The expression of amino acid transporters is known to vary during acute pancreatitis (AP) except for LAT1 (slc7a5), the expression of which remains stable. LAT1 supports cell growth by importing leucine and thereby stimulates mammalian target of rapamycin (mTOR) activity, a phenomenon often observed in cancer cells. The mechanisms by which LAT1 influences physiological and pathophysiological processes and affects disease progression in the pancreas are not yet known.
AIM To evaluate the role of LAT1 in the development of and recovery from AP.
METHODS AP was induced with caerulein (cae) injections in female and male mice expressing LAT1 or after its knockout (LAT1 Cre/LoxP). The development of the initial AP injury and its recovery were followed for seven days after cae injections by daily measuring body weight, assessing microscopical tissue architecture, mRNA and protein expression, protein synthesis, and enzyme activity levels, as well as by testing the recruitment of immune cells by FACS and ELISA.
RESULTS The initial injury, evaluated by measurements of plasma amylase, lipase, and trypsin activity, as well as the gene expression of dedifferentiation markers, did not differ between the groups. However, early metabolic adaptations that support regeneration at later stages were blunted in LAT1 knockout mice. Especially in females, we observed less mTOR reactivation and dysfunctional autophagy. The later regeneration phase was clearly delayed in female LAT1 knockout mice, which did not regain normal expression of the pancreas-specific differentiation markers recombining binding protein suppressor of hairless-like protein (rbpjl) and basic helix-loop-helix family member A15 (mist1). Amylase mRNA and protein levels remained lower, and, strikingly, female LAT1 knockout mice presented signs of fibrosis lasting until day seven. In contrast, pancreas morphology had returned to normal in wild-type littermates.
CONCLUSION LAT1 supports the regeneration of acinar cells after AP. Female mice lacking LAT1 exhibited more pronounced alterations than male mice, indicating a sexual dimorphism of amino acid metabolism.
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Affiliation(s)
- Cristina M Hagen
- Institute of Physiology, University of Zurich, Zurich 8057, ZH, Switzerland
| | - Eva Roth
- Institute of Physiology, University of Zurich, Zurich 8057, ZH, Switzerland
| | - Theresia Reding Graf
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, Zurich University Hospital, Zurich 8091, ZH, Switzerland
| | - François Verrey
- Institute of Physiology, University of Zurich, Zurich 8057, ZH, Switzerland
| | - Rolf Graf
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, Zurich University Hospital, Zurich 8091, ZH, Switzerland
| | - Anurag Gupta
- Swiss Hepato-Pancreato-Biliary Center, Department of Visceral and Transplantation Surgery, Zurich University Hospital, Zurich 8091, ZH, Switzerland
| | - Giovanni Pellegrini
- Institute of Veterinary Pathology, University of Zurich, Zurich 8057, ZH, Switzerland
| | - Nadège Poncet
- Institute of Physiology, University of Zurich, Zurich 8057, ZH, Switzerland
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27
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Wu F, Xiong G, Chen Z, Lei C, Liu Q, Bai Y. SLC3A2 inhibits ferroptosis in laryngeal carcinoma via mTOR pathway. Hereditas 2022; 159:6. [PMID: 35057861 PMCID: PMC8772086 DOI: 10.1186/s41065-022-00225-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 01/03/2022] [Indexed: 01/22/2023] Open
Abstract
Objective This study aimed to explore the mRNA and protein expression of SLC3A2 in laryngeal carcinoma cells and tissues, and functional regulatory mechanism of SLC3A2 in cell ferroptosis of laryngeal carcinoma. Methods We chose the key gene-SLC3A2 of DEGs from TCGA by bioinformatics analysis, and then we constructed stable knockdown of SLC3A2 in laryngeal carcinoma cells. MTT assay and clonogenic assay were used to determine cell viability and cell growth, respectively. The mRNA and protein expression were determined by RT-qPCR and western blotting, respectively. Xenograft tumor model was used to determine the role of SLC3A2 in tumor growth. Results The results of limma analysis recovered that 92 genes were involved in both upregulated DEGs and high risk of poor prognosis, whereas 36 genes were involved in both downregulated DEGs and low risk of poor prognosis. Pathway enrichment analysis indicated that mTOR signaling pathway and ferroptosis exerted a role in regulating these intersection genes. Moreover, SLC3A2 is a key gene in ferroptosis in laryngeal carcinoma. SLC3A2 is highly expressed in laryngeal carcinoma tissues and cells. Patients with high SLC3A2 expression exerted poor survival. SLC3A2 deficiency inhibited cell proliferation and foci formation. Furthermore, knockdown of SLC3A2 expression induced the efficacy of ferroptosis and suppressed ferroptosis related proteins expression. Mechanically, SLC3A2 deficiency facilitated ferroptosis through upregulating the expression of mTOR and P70S6K, whereas inhibited p-mTOR and p-P70S6K expression in laryngeal carcinoma cells. SLC3A2 deficiency inhibited tumorigenesis in nude mice. Conclusion Our study suggests that SLC3A2 negatively regulates ferroptosis through mTOR pathway in laryngeal carcinoma.
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28
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Taslimifar M, Faltys M, Kurtcuoglu V, Verrey F, Makrides V. Analysis of L-leucine amino acid transporter species activity and gene expression by human blood brain barrier hCMEC/D3 model reveal potential LAT1, LAT4, B 0AT2 and y +LAT1 functional cooperation. J Cereb Blood Flow Metab 2022; 42:90-103. [PMID: 34427144 PMCID: PMC8721536 DOI: 10.1177/0271678x211039593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In the CNS, amino acid (AA) neurotransmitters and neurotransmitter precursors are subject to tight homeostatic control mediated by blood-brain barrier (BBB) solute carrier amino acid transporters (AATs). Since the BBB is composed of multiple closely apposed cell types and opportunities for human in vivo studies are limited, we used in vitro and computational approaches to investigate human BBB AAT activity and regulation. Quantitative real-time PCR (qPCR) of the human BBB endothelial cell model hCMEC/D3 (D3) was used to determine expression of selected AAT, tight junction (TJ), and signal transduction (ST) genes under various culture conditions. L-leucine uptake data were interrogated with a computational model developed by our group for calculating AAT activity in complex cell cultures. This approach is potentially applicable to in vitro cell culture drug studies where multiple "receptors" may mediate observed responses. Of 7 Leu AAT genes expressed by D3 only the activity of SLC7A5-SLC3A2/LAT1-4F2HC (LAT1), SLC43A2/LAT4 (LAT4) and sodium-dependent AATs, SLC6A15/B0AT2 (B0AT2), and SLC7A7/y+LAT1 (y+LAT1) were calculated to be required for Leu uptake. Therefore, D3 Leu transport may be mediated by a potentially physiologically relevant functional cooperation between the known BBB AAT, LAT1 and obligatory exchange (y+LAT1), facilitative diffusion (LAT4), and sodium symporter (B0AT2) transporters.
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Affiliation(s)
- Mehdi Taslimifar
- The Interface Group, Institute of Physiology, University of Zürich, Zürich, Switzerland.,Epithelial Transport Group, Institute of Physiology, University of Zürich, Zürich, Switzerland
| | - Martin Faltys
- Epithelial Transport Group, Institute of Physiology, University of Zürich, Zürich, Switzerland.,Department of Intensive Care Medicine, University Hospital, University of Bern, Bern, Switzerland
| | - Vartan Kurtcuoglu
- The Interface Group, Institute of Physiology, University of Zürich, Zürich, Switzerland.,National Center of Competence in Research, Kidney CH, Switzerland
| | - François Verrey
- Epithelial Transport Group, Institute of Physiology, University of Zürich, Zürich, Switzerland.,National Center of Competence in Research, Kidney CH, Switzerland
| | - Victoria Makrides
- The Interface Group, Institute of Physiology, University of Zürich, Zürich, Switzerland.,Epithelial Transport Group, Institute of Physiology, University of Zürich, Zürich, Switzerland.,EIC BioMedical Labs, Norwood, MA, USA
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Protective Effects of Glutamine and Leucine Supplementation on Sepsis-Induced Skeletal Muscle Injuries. Int J Mol Sci 2021; 22:ijms222313003. [PMID: 34884807 PMCID: PMC8657647 DOI: 10.3390/ijms222313003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 11/29/2021] [Accepted: 11/29/2021] [Indexed: 01/02/2023] Open
Abstract
This study investigated the effects of l-glutamine (Gln) and/or l-leucine (Leu) administration on sepsis-induced skeletal muscle injuries. C57BL/6J mice were subjected to cecal ligation and puncture to induce polymicrobial sepsis and then given an intraperitoneal injection of Gln, Leu, or Gln plus Leu beginning at 1 h after the operation with re-injections every 24 h. All mice were sacrificed on either day 1 or day 4 after the operation. Blood and muscles were collected for analysis of inflammation and oxidative damage-related biomolecules. Results indicated that both Gln and Leu supplementation alleviated sepsis-induced skeletal muscle damage by reducing monocyte infiltration, calpain activity, and mRNA expression levels of inflammatory cytokines and hypoxia-inducible factor-1α. Furthermore, septic mice treated with Gln had higher percentages of blood anti-inflammatory monocytes and muscle M2 macrophages, whereas Leu treatment enhanced the muscle expressions of mitochondrion-related genes. However, there were no synergistic effects when Gln and Leu were simultaneously administered. These findings suggest that both Gln and Leu had prominent abilities to attenuate inflammation and degradation of skeletal muscles in the early and/or late phases of sepsis. Moreover, Gln promoted the switch of leukocytes toward an anti-inflammatory phenotype, while Leu treatment maintained muscle bioenergetic function.
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Girgis J, Yang D, Chakroun I, Liu Y, Blais A. Six1 promotes skeletal muscle thyroid hormone response through regulation of the MCT10 transporter. Skelet Muscle 2021; 11:26. [PMID: 34809717 PMCID: PMC8607597 DOI: 10.1186/s13395-021-00281-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 10/29/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The Six1 transcription factor is implicated in controlling the development of several tissue types, notably skeletal muscle. Six1 also contributes to muscle metabolism and its activity is associated with the fast-twitch, glycolytic phenotype. Six1 regulates the expression of certain genes of the fast muscle program by directly stimulating their transcription or indirectly acting through a long non-coding RNA. We hypothesized that additional mechanisms of action of Six1 might be at play. METHODS A combined analysis of gene expression profiling and genome-wide location analysis data was performed. Results were validated using in vivo RNA interference loss-of-function assays followed by measurement of gene expression by RT-PCR and transcriptional reporter assays. RESULTS The Slc16a10 gene, encoding the thyroid hormone transmembrane transporter MCT10, was identified as a gene with a transcriptional enhancer directly bound by Six1 and requiring Six1 activity for full expression in adult mouse tibialis anterior, a predominantly fast-twitch muscle. Of the various thyroid hormone transporters, MCT10 mRNA was found to be the most abundant in skeletal muscle, and to have a stronger expression in fast-twitch compared to slow-twitch muscle groups. Loss-of-function of MCT10 in the tibialis anterior recapitulated the effect of Six1 on the expression of fast-twitch muscle genes and led to lower activity of a thyroid hormone receptor-dependent reporter gene. CONCLUSIONS These results shed light on the molecular mechanisms controlling the tissue expression profile of MCT10 and identify modulation of the thyroid hormone signaling pathway as an additional mechanism by which Six1 influences skeletal muscle metabolism.
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Affiliation(s)
- John Girgis
- Faculty of Medicine, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, K1H 8M5, Canada.,Ottawa Institute of Systems Biology, Ottawa, Ontario, Canada.,Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Dabo Yang
- Faculty of Medicine, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, K1H 8M5, Canada.,Ottawa Institute of Systems Biology, Ottawa, Ontario, Canada
| | - Imane Chakroun
- Faculty of Medicine, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, K1H 8M5, Canada.,Ottawa Institute of Systems Biology, Ottawa, Ontario, Canada
| | - Yubing Liu
- Faculty of Medicine, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, K1H 8M5, Canada.,Ottawa Institute of Systems Biology, Ottawa, Ontario, Canada
| | - Alexandre Blais
- Faculty of Medicine, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, K1H 8M5, Canada. .,Ottawa Institute of Systems Biology, Ottawa, Ontario, Canada. .,University of Ottawa Centre for Inflammation, Immunity and Infection (CI3), Ottawa, Ontario, Canada.
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31
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Mazzulla M, Hodson N, Lees M, Scaife PJ, Smith K, Atherton PJ, Kumbhare D, Moore DR. LAT1 and SNAT2 Protein Expression and Membrane Localization of LAT1 Are Not Acutely Altered by Dietary Amino Acids or Resistance Exercise Nor Positively Associated with Leucine or Phenylalanine Incorporation in Human Skeletal Muscle. Nutrients 2021; 13:nu13113906. [PMID: 34836160 PMCID: PMC8624011 DOI: 10.3390/nu13113906] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/13/2021] [Accepted: 10/22/2021] [Indexed: 12/26/2022] Open
Abstract
The influx of essential amino acids into skeletal muscle is primarily mediated by the large neutral amino acid transporter 1 (LAT1), which is dependent on the glutamine gradient generated by the sodium-dependent neutral amino acid transporter 2 (SNAT2). The protein expression and membrane localization of LAT1 may be influenced by amino acid ingestion and/or resistance exercise, although its acute influence on dietary amino acid incorporation into skeletal muscle protein has not been investigated. In a group design, healthy males consumed a mixed carbohydrate (0.75 g·kg-1) crystalline amino acid (0.25 g·kg-1) beverage enriched to 25% and 30% with LAT1 substrates L-[1-13C]leucine (LEU) and L-[ring-2H5]phenylalanine (PHE), respectively, at rest (FED: n = 7, 23 ± 5 y, 77 ± 4 kg) or after a bout of resistance exercise (EXFED: n = 7, 22 ± 2 y, 78 ± 11 kg). Postprandial muscle biopsies were collected at 0, 120, and 300 min to measure transporter protein expression (immunoblot), LAT1 membrane localization (immunofluorescence), and dietary amino acid incorporation into myofibrillar protein (ΔLEU and ΔPHE). Basal LAT1 and SNAT2 protein contents were correlated with each other (r = 0.55, p = 0.04) but their expression did not change across time in FED or EXFED (all, p > 0.05). Membrane localization of LAT1 did not change across time in FED or EXFED whether measured as outer 1.5 µm intensity or membrane-to-fiber ratio (all, p > 0.05). Basal SNAT2 protein expression was not correlated with ΔLEU or ΔPHE (all, p ≥ 0.05) whereas basal LAT1 expression was negatively correlated with ΔPHE in FED (r = -0.76, p = 0.04) and EXFED (r = -0.81, p = 0.03) but not ΔLEU (p > 0.05). Basal LAT1 membrane localization was not correlated with ΔLEU or ΔPHE (all, p > 0.05). Our results suggest that LAT1/SNAT2 protein expression and LAT1 membrane localization are not influenced by acute anabolic stimuli and do not positively influence the incorporation of dietary amino acids for de novo myofibrillar protein synthesis in healthy young males.
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Affiliation(s)
- Michael Mazzulla
- Department of Exercise Sciences, Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON M5S 2C9, Canada; (M.M.); (N.H.); (M.L.)
| | - Nathan Hodson
- Department of Exercise Sciences, Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON M5S 2C9, Canada; (M.M.); (N.H.); (M.L.)
| | - Matthew Lees
- Department of Exercise Sciences, Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON M5S 2C9, Canada; (M.M.); (N.H.); (M.L.)
| | - Paula J. Scaife
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRC, Centre of Metabolism, Ageing and Physiology, School of Medicine, University of Nottingham, Derby DE22 3DT, UK; (P.J.S.); (K.S.); (P.J.A.)
| | - Kenneth Smith
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRC, Centre of Metabolism, Ageing and Physiology, School of Medicine, University of Nottingham, Derby DE22 3DT, UK; (P.J.S.); (K.S.); (P.J.A.)
| | - Philip J. Atherton
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRC, Centre of Metabolism, Ageing and Physiology, School of Medicine, University of Nottingham, Derby DE22 3DT, UK; (P.J.S.); (K.S.); (P.J.A.)
| | - Dinesh Kumbhare
- Department of Medicine, University of Toronto, Toronto, ON M5S 2C9, Canada;
| | - Daniel R. Moore
- Department of Exercise Sciences, Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON M5S 2C9, Canada; (M.M.); (N.H.); (M.L.)
- Correspondence: ; Tel.: +1-(416)-946-4088
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32
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Wang S, Chen C, Guan C, Qiu L, Zhang L, Zhang S, Zhou H, Du H, Li C, Wu Y, Chang H, Wang T. Effects of membrane transport activity and cell metabolism on the unbound drug concentrations in the skeletal muscle and liver of drugs: A microdialysis study in rats. Pharmacol Res Perspect 2021; 9:e00879. [PMID: 34628723 PMCID: PMC8502442 DOI: 10.1002/prp2.879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 09/20/2021] [Indexed: 11/09/2022] Open
Abstract
The unbound concentrations of 14 commercial drugs, including five non-efflux/uptake transporter substrates-Class I, five efflux transporter substrates-class II and four influx transporter substrates-Class III, were simultaneously measured in rat liver, muscle, and blood via microanalysis. Kpuu,liver and Kpuu,muscle were calculated to evaluate the membrane transport activity and cell metabolism on the unbound drug concentrations in the skeletal muscle and liver. For Class I compounds, represented by antipyrine, unbound concentrations among liver, muscle and blood are symmetrically distributed when compound hepatic clearance is low. And when compound hepatic clearance is high, unbound concentrations among liver, muscle and blood are asymmetrically distributed, such as Propranolol. For Class II and III compounds, overall, the unbound concentrations among liver, muscle, and blood are asymmetrically distributed due to a combination of hepatic metabolism and efflux and/or influx transporter activity.
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Affiliation(s)
- Shuyao Wang
- DMPK Department, Pharmaron Inc., Beijing, China
| | - Chun Chen
- DMPK Department, Pharmaron Inc., Beijing, China
| | - Chi Guan
- DMPK Department, Pharmaron Inc., Beijing, China
| | - Liping Qiu
- DMPK Department, Pharmaron Inc., Beijing, China
| | - Lei Zhang
- DMPK Department, Pharmaron Inc., Beijing, China
| | | | - Hongyu Zhou
- DMPK Department, Pharmaron Inc., Beijing, China
| | - Hongwen Du
- DMPK Department, Pharmaron Inc., Beijing, China
| | - Chen Li
- DMPK Department, Pharmaron Inc., Beijing, China
| | - Yaqiong Wu
- DMPK Department, Pharmaron Inc., Beijing, China
| | - Hang Chang
- DMPK Department, Pharmaron Inc., Beijing, China
| | - Tao Wang
- DMPK Department, Pharmaron Inc., Beijing, China
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Effects of maternal gestational diet, with or without methionine, on muscle transcriptome of Bos indicus-influenced beef calves following a vaccine-induced immunological challenge. PLoS One 2021; 16:e0253810. [PMID: 34166453 PMCID: PMC8224847 DOI: 10.1371/journal.pone.0253810] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/11/2021] [Indexed: 12/13/2022] Open
Abstract
Maternal nutrition during gestation can cause epigenetic effects that translate to alterations in gene expression in offspring. This 2-year study employed RNA-sequencing technology to evaluate the pre- and post-vaccination muscle transcriptome of early-weaned Bos indicus-influenced beef calves born from dams offered different supplementation strategies from 57 ± 5 d prepartum until 17 ± 5 d postpartum. Seventy-two Brangus heifers (36 heifers/yr) were stratified by body weight and body condition score and assigned to bahiagrass pastures (3 heifers/pasture/yr). Treatments were randomly assigned to pastures and consisted of (i) no pre- or postpartum supplementation (NOSUP), (ii) pre- and postpartum supplementation of protein and energy using 7.2 kg of dry matter/heifer/wk of molasses + urea (MOL), or (iii) MOL fortified with 105 g/heifer/wk of methionine hydroxy analog (MOLMET). Calves were weaned on d 147 of the study. On d 154, 24 calves/yr (8 calves/treatment) were randomly selected and individually limit-fed a high-concentrate diet until d 201. Calves were vaccinated on d 160. Muscle biopsies were collected from the same calves (4 calves/treatment/day/yr) on d 154 (pre-vaccination) and 201 (post-vaccination) for gene expression analysis using RNA sequencing. Molasses maternal supplementation led to a downregulation of genes associated with muscle cell differentiation and development along with intracellular signaling pathways (e.g., Wnt and TGF-β signaling pathway) compared to no maternal supplementation. Maternal fortification with methionine altered functional gene-sets involved in amino acid transport and metabolism and the one-carbon cycle. In addition, muscle transcriptome was impacted by vaccination with a total of 2,396 differentially expressed genes (FDR ≤ 0.05) on d 201 vs. d 154. Genes involved in cell cycle progression, extracellular matrix, and collagen formation were upregulated after vaccination. This study demonstrated that maternal supplementation of energy and protein, with or without, methionine has long-term implications on the muscle transcriptome of offspring and potentially influence postnatal muscle development.
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Granitzer S, Widhalm R, Forsthuber M, Ellinger I, Desoye G, Hengstschläger M, Zeisler H, Salzer H, Gundacker C. Amino Acid Transporter LAT1 (SLC7A5) Mediates MeHg-Induced Oxidative Stress Defense in the Human Placental Cell Line HTR-8/SVneo. Int J Mol Sci 2021; 22:ijms22041707. [PMID: 33567754 PMCID: PMC7915079 DOI: 10.3390/ijms22041707] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/02/2021] [Accepted: 02/05/2021] [Indexed: 12/25/2022] Open
Abstract
The placental barrier can protect the fetus from contact with harmful substances. The potent neurotoxin methylmercury (MeHg), however, is very efficiently transported across the placenta. Our previous data suggested that L-type amino acid transporter (LAT)1 is involved in placental MeHg uptake, accepting MeHg-L-cysteine conjugates as substrate due to structural similarity to methionine. The aim of the present study was to investigate the antioxidant defense of placental cells to MeHg exposure and the role of LAT1 in this response. When trophoblast-derived HTR-8/SVneo cells were LAT1 depleted by siRNA-mediated knockdown, they accumulated less MeHg. However, they were more susceptible to MeHg-induced toxicity. This was evidenced in decreased cell viability at a usually noncytotoxic concentration of 0.03 µM MeHg (~6 µg/L). Treatment with ≥0.3 µM MeHg increased cytotoxicity, apoptosis rate, and oxidative stress of HTR-8/SVneo cells. These effects were enhanced under LAT1 knockdown. Reduced cell number was seen when MeHg-exposed cells were cultured in medium low in cysteine, a constituent of the tripeptide glutathione (GSH). Because LAT1-deficient HTR-8/SVneo cells have lower GSH levels than control cells (independent of MeHg treatment), we conclude that LAT1 is essential for de novo synthesis of GSH, required to counteract oxidative stress. Genetic predisposition to decreased LAT1 function combined with MeHg exposure could increase the risk of placental damage.
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Affiliation(s)
- Sebastian Granitzer
- Karl-Landsteiner Private University for Health Sciences, A-3500 Krems, Austria; (S.G.); (R.W.)
- Institute of Medical Genetics, Medical University of Vienna, A-1090 Vienna, Austria; (M.F.); (M.H.)
| | - Raimund Widhalm
- Karl-Landsteiner Private University for Health Sciences, A-3500 Krems, Austria; (S.G.); (R.W.)
- Institute of Medical Genetics, Medical University of Vienna, A-1090 Vienna, Austria; (M.F.); (M.H.)
| | - Martin Forsthuber
- Institute of Medical Genetics, Medical University of Vienna, A-1090 Vienna, Austria; (M.F.); (M.H.)
| | - Isabella Ellinger
- Department of Pathophysiology and Allergy Research, Medical University of Vienna, A-1090 Vienna, Austria;
| | - Gernot Desoye
- Department of Obstetrics and Gynecology, Medical University of Graz, A-8036 Graz, Austria;
| | - Markus Hengstschläger
- Institute of Medical Genetics, Medical University of Vienna, A-1090 Vienna, Austria; (M.F.); (M.H.)
| | - Harald Zeisler
- Department of Obstetrics and Gynecology, Medical University Vienna, A-1090 Vienna, Austria;
| | - Hans Salzer
- Clinical Department of Pediatrics and Adolescent Medicine, University Hospital Tulln, A-3430 Tulln, Austria;
| | - Claudia Gundacker
- Institute of Medical Genetics, Medical University of Vienna, A-1090 Vienna, Austria; (M.F.); (M.H.)
- Correspondence: ; Tel.: +43-1-40160-56503
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Cormerais Y, Vučetić M, Parks SK, Pouyssegur J. Amino Acid Transporters Are a Vital Focal Point in the Control of mTORC1 Signaling and Cancer. Int J Mol Sci 2020; 22:E23. [PMID: 33375025 PMCID: PMC7792758 DOI: 10.3390/ijms22010023] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 11/26/2020] [Accepted: 11/27/2020] [Indexed: 12/14/2022] Open
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) integrates signals from growth factors and nutrients to control biosynthetic processes, including protein, lipid, and nucleic acid synthesis. Dysregulation in the mTORC1 network underlies a wide array of pathological states, including metabolic diseases, neurological disorders, and cancer. Tumor cells are characterized by uncontrolled growth and proliferation due to a reduced dependency on exogenous growth factors. The genetic events underlying this property, such as mutations in the PI3K-Akt and Ras-Erk signaling networks, lead to constitutive activation of mTORC1 in nearly all human cancer lineages. Aberrant activation of mTORC1 has been shown to play a key role for both anabolic tumor growth and resistance to targeted therapeutics. While displaying a growth factor-independent mTORC1 activity and proliferation, tumors cells remain dependent on exogenous nutrients such as amino acids (AAs). AAs are an essential class of nutrients that are obligatory for the survival of any cell. Known as the building blocks of proteins, AAs also act as essential metabolites for numerous biosynthetic processes such as fatty acids, membrane lipids and nucleotides synthesis, as well as for maintaining redox homeostasis. In most tumor types, mTORC1 activity is particularly sensitive to intracellular AA levels. This dependency, therefore, creates a targetable vulnerability point as cancer cells become dependent on AA transporters to sustain their homeostasis. The following review will discuss the role of AA transporters for mTORC1 signaling in cancer cells and their potential as therapeutic drug targets.
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Affiliation(s)
- Yann Cormerais
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Milica Vučetić
- Department of Medical Biology, Centre Scientifique de Monaco (CSM), 98000 Monaco, Monaco; (M.V.); (S.K.P.)
| | - Scott K. Parks
- Department of Medical Biology, Centre Scientifique de Monaco (CSM), 98000 Monaco, Monaco; (M.V.); (S.K.P.)
| | - Jacques Pouyssegur
- Department of Medical Biology, Centre Scientifique de Monaco (CSM), 98000 Monaco, Monaco; (M.V.); (S.K.P.)
- CNRS, INSERM, Centre A. Lacassagne, Faculté de Médecine (IRCAN), Université Côte d’Azur, 06107 Nice, France
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36
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Sokolov AM, Holmberg JC, Feliciano DM. The amino acid transporter Slc7a5 regulates the mTOR pathway and is required for granule cell development. Hum Mol Genet 2020; 29:3003-3013. [PMID: 32821949 PMCID: PMC7645712 DOI: 10.1093/hmg/ddaa186] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/03/2020] [Accepted: 08/15/2020] [Indexed: 12/11/2022] Open
Abstract
Pathogenic mutations in the solute carrier family 7 member 5 (SLC7A5) gene, which encodes an amino acid transporter cause microcephaly and seizures, yet the mechanisms responsible for these phenotypes are unclear. Models have demonstrated that Slc7a5 deletion is embryonic lethal and that these embryos lack a fully formed telencephalon. This phenotype is similar to that of mammalian target of rapamycin (mTOR) protein kinase deletion or mTOR inhibition. Notably, in many cells, Slc7a5 import of amino acids is required to maintain mTOR activity. Slc7a5 is present within neurogenic regions during embryogenesis, is found in cultured neurons and can modulate neuronal electrophysiological properties. However, Slc7a5 is also highly expressed within endothelial cells of the blood-brain barrier where removal in conditional mice leads to severe behavioral defects and non-cell autonomous changes in neurons. Therefore, the extent that neural Slc7a5 is required for development is unclear. Here, subventricular zone neural stem cells that generate olfactory bulb granule cell neurons were electroporated with SLC7A5 or Slc7a5 short hairpin RNA encoding plasmids. Although early phases of neural development were unaltered, Slc7a5 knockdown effected late phases of GC dendrite maturation and survival. Slc7a5 knockdown also decreased mTOR pathway activity. Ras homolog enriched in brain, an mTOR activator, rescued the effect of Slc7a5 knockdown on mTOR pathway activity and dendrite arbors. The data presented here demonstrate that Slc7a5 is required for GC mTOR pathway activity, maturation and survival, which may help explain why Slc7a5 mutations prevent normal brain development and function.
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Affiliation(s)
- Aidan M Sokolov
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
| | - Jennie C Holmberg
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
| | - David M Feliciano
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
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Zhang J, Xu Y, Li D, Fu L, Zhang X, Bao Y, Zheng L. Review of the Correlation of LAT1 With Diseases: Mechanism and Treatment. Front Chem 2020; 8:564809. [PMID: 33195053 PMCID: PMC7606929 DOI: 10.3389/fchem.2020.564809] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 09/17/2020] [Indexed: 12/17/2022] Open
Abstract
LAT1 is a member of the system L transporter family. The main role of the LAT1 is to transport specific amino acids through cell membranes to provide nutrients to cells and participate in several metabolic pathways. It also contributes to the transport of hormones and some drugs, which are essential for the development and treatment of some diseases. In recent years, many studies have shown that LAT1 is related to cancer, obesity, diabetes, and other diseases. However, the specific mechanism underlying the influence of LAT1 on such conditions remains unclear. Through the increasing number of studies on LAT1, we have obtained a preliminary understanding on the function of LAT1 in diseases. These studies also provide a theoretical basis for finding treatments for LAT1-related diseases, such as cancer. This review summarizes the function and mechanism of LAT1 in different diseases and the treatment of LAT1-related diseases. It also provides support for the development of novel and reliable disease treatments.
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Affiliation(s)
- Jingshun Zhang
- Reproductive Medical Center, Department of Obstetrics and Gynecology, The Second Hospital of Jilin University, Changchun, China
| | - Ying Xu
- Reproductive Medical Center, Department of Obstetrics and Gynecology, The Second Hospital of Jilin University, Changchun, China
| | - Dandan Li
- Reproductive Medical Center, Department of Obstetrics and Gynecology, The Second Hospital of Jilin University, Changchun, China
| | - Lulu Fu
- Reproductive Medical Center, Department of Obstetrics and Gynecology, The Second Hospital of Jilin University, Changchun, China
| | - Xueying Zhang
- Reproductive Medical Center, Department of Obstetrics and Gynecology, The Second Hospital of Jilin University, Changchun, China
| | - Yigang Bao
- Reproductive Medical Center, Department of Obstetrics and Gynecology, The Second Hospital of Jilin University, Changchun, China
| | - Lianwen Zheng
- Reproductive Medical Center, Department of Obstetrics and Gynecology, The Second Hospital of Jilin University, Changchun, China
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Xu J, Jiang C, Cai Y, Guo Y, Wang X, Zhang J, Xu J, Xu K, Zhu W, Wang S, Zhang F, Geng M, Han Y, Ning Q, Xu P, Meng L, Lu S. Intervening upregulated SLC7A5 could mitigate inflammatory mediator by mTOR-P70S6K signal in rheumatoid arthritis synoviocytes. Arthritis Res Ther 2020; 22:200. [PMID: 32867828 PMCID: PMC7457370 DOI: 10.1186/s13075-020-02296-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 08/19/2020] [Indexed: 12/12/2022] Open
Abstract
Objective The disruption of metabolic events and changes to nutrient and oxygen availability due to sustained inflammation in RA increases the demand of bioenergetic and biosynthetic processes within the damaged tissue. The current study aimed to understand the molecular mechanisms of SLC7A5 (amino acid transporter) in synoviocytes of RA patients. Methods Synovial tissues were obtained from OA and RA patients. Fibroblast-like synoviocytes (FLS) were isolated, and SLC7A5 expression was examined by using RT-qPCR, immunofluorescence, and Western blotting. RNAi and antibody blocking treatments were used to knockdown SLC7A5 expression or to block its transporter activities. mTOR activity assay and MMP expression levels were monitored in RA FLS under amino acid deprivation or nutrient-rich conditions. Results RA FLS displayed significantly upregulated expression of SLC7A5 compared to OA FLS. Cytokine IL-1β was found to play a crucial role in upregulating SLC7A5 expression via the NF-κB pathway. Intervening SLC7A5 expression with RNAi or blocking its function by monoclonal antibody ameliorated MMP3 and MMP13 protein expression. Conversely, upregulation of SLC7A5 or tryptophan supplementation enhanced mTOR-P70S6K signals which promoted the protein translation of MMP3 and MMP13 in RA FLS. Conclusion Activated NF-κB pathway upregulates SLC7A5, which enhances the mTOR-P70S6K activity and MMP3 and MMP13 expression in RA FLS.
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Affiliation(s)
- Jing Xu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Congshan Jiang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Yongsong Cai
- Department of Joint Surgery, Xi'an Hong Hui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Yuanxu Guo
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Xipeng Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Jiaxiang Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Jiawen Xu
- Department of Joint Surgery, Xi'an Hong Hui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Ke Xu
- Department of Joint Surgery, Xi'an Hong Hui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Wenhua Zhu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Si Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Fujun Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Manman Geng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Yan Han
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Qilan Ning
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Peng Xu
- Department of Joint Surgery, Xi'an Hong Hui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Liesu Meng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Shemin Lu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China. .,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, Shaanxi, People's Republic of China.
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Alles SR, Gomez K, Moutal A, Khanna R. Putative roles of SLC7A5 (LAT1) transporter in pain. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2020; 8:100050. [PMID: 32715162 PMCID: PMC7369351 DOI: 10.1016/j.ynpai.2020.100050] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/23/2020] [Accepted: 06/24/2020] [Indexed: 12/13/2022]
Abstract
Large amino acid transporter 1 (LAT1), also known as SLC7A5, is an essential amino acid transporter that forms a heterodimeric complex with the glycoprotein cell-surface antigen heavy chain (4F2hc (CD98, SLC3A2)). Within nociceptive pathways, LAT1 is expressed in the dorsal root ganglia and spinal cord. Although LAT1 expression is upregulated following spinal cord injury, little is known about LAT1 in neuropathic pain. To date, only circumstantial evidence supports LAT1/4F2hc's role in pain. Notably, LAT1's expression and regulation link it to key cell types and pathways implicated in pain. Transcriptional regulation of LAT1 expression occurs via the Wnt/frizzled/β-catenin signal transduction pathway, which has been shown to be involved in chronic pain. The LAT1/4F2hc complex may also be involved in pain pathways related to T- and B-cells. LAT1's expression induces activation of the mammalian target of rapamycin (mTOR) signaling axis, which is involved in inflammation and neuropathic pain. Similarly, hypoxia and cancer induce activation of hypoxia-inducible factor 2 alpha, promoting not only LAT1's expression but also mTORC1's activation. Perhaps the strongest evidence linking LAT1 to pain is its interactions with key voltage-gated ion channels connected to nociception, namely the voltage-gated potassium channels Kv1.1 and Kv1.2 and the voltage-gated sodium channel Nav1.7. Through functional regulation of these channels, LAT1 may play a role in governing the excitatory to inhibitory ratio which is altered in chronic neuropathic pain states. Remarkably, the most direct role for LAT1 in pain is to mediate the influx of gabapentin and pregabalin, two first-line neuropathic pain drugs, that indirectly inhibit high voltage-activated calcium channel auxiliary subunit α2δ-1. In this review, we discuss the expression, regulation, relevant signaling pathways, and protein interactions of LAT1 that may link it to the development and/or maintenance of pain. We hypothesize that LAT1 expressed in nociceptive pathways may be a viable new target in pain.
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Affiliation(s)
- Sascha R.A. Alles
- Department of Anesthesiology and Critical Care Medicine, University of New Mexico School of Medicine, United States
| | - Kimberly Gomez
- Department of Pharmacology, University of Arizona, United States
| | - Aubin Moutal
- Department of Pharmacology, University of Arizona, United States
| | - Rajesh Khanna
- Department of Pharmacology, University of Arizona, United States
- Department of Anesthesiology, College of Medicine, The University of Arizona, Tucson, AZ 85724, United States
- BIO5 Institute, University of Arizona, 1657 East Helen Street Tucson, AZ 85719, United States
- Center for Innovation in Brain Sciences, University of Arizona, Tucson, AZ 85721, United States
- Regulonix Holding Inc., Tucson, AZ, United States
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40
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Huska B, Niccoli S, Phenix CP, Lees SJ. Leucine Potentiates Glucose-mediated 18F-FDG Uptake in Brown Adipose Tissue via β-Adrenergic Activation. Biomedicines 2020; 8:biomedicines8060159. [PMID: 32545834 PMCID: PMC7345234 DOI: 10.3390/biomedicines8060159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/27/2020] [Accepted: 06/10/2020] [Indexed: 01/07/2023] Open
Abstract
Significant depots of brown adipose tissue (BAT) have been identified in many adult humans through positron emission tomography (PET), with the amount of BAT being inversely correlated with obesity. As dietary activation of BAT has implications for whole body glucose metabolism, leucine was used in the present study to determine its ability to promote BAT activation resulting in increased glucose uptake. In order to assess this, 2-deoxy-2-(fluorine-18)fluoro-d-glucose (18F-FDG) uptake was measured in C57BL/6 mice using microPET after treatment with leucine, glucose, or both in interscapular BAT (IBAT). Pretreatment with propranolol (PRP) was used to determine the role of β-adrenergic activation in glucose and leucine-mediated 18F-FDG uptake. Analysis of maximum standardized uptake values (SUVMAX) determined that glucose administration increased 18F-FDG uptake in IBAT by 25.3%. While leucine did not promote 18F-FDG uptake alone, it did potentiate glucose-mediated 18F-FDG uptake, increasing 18F-FDG uptake in IBAT by 22.5%, compared to glucose alone. Pretreatment with PRP prevented the increase in IBAT 18F-FDG uptake following the combination of glucose and leucine administration. These data suggest that leucine is effective in promoting BAT 18F-FDG uptake through β-adrenergic activation in combination with glucose.
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Affiliation(s)
- Brenda Huska
- Biology, Lakehead University, Thunder Bay, ON P7B 5E1, Canada;
| | - Sarah Niccoli
- Medical Sciences, Lakehead University Faculty of Medicine, Thunder Bay, ON P7B 5E1, Canada;
- Northern Ontario School of Medicine, Medical Sciences Division, Thunder Bay, ON P7B 5E1, Canada
| | - Christopher P. Phenix
- Northern Ontario School of Medicine, Medical Sciences Division, Thunder Bay, ON P7B 5E1, Canada
- Chemistry, University of Saskatchewan, Saskatoon, SK S7N 5C9, Canada
- Thunder Bay Regional Health Research Institute, Thunder Bay, ON P7A 7T1, Canada
- Correspondence: (C.P.P.); (S.J.L.); Tel.: +1-(306)-966-4193 (C.P.P.); +1-(807)-766-7435 (S.J.L.); Fax: +1-(306)-966-4730 (C.P.P.); +1-(807)-766-7362 (S.J.L.)
| | - Simon J. Lees
- Biology, Lakehead University, Thunder Bay, ON P7B 5E1, Canada;
- Medical Sciences, Lakehead University Faculty of Medicine, Thunder Bay, ON P7B 5E1, Canada;
- Northern Ontario School of Medicine, Medical Sciences Division, Thunder Bay, ON P7B 5E1, Canada
- Correspondence: (C.P.P.); (S.J.L.); Tel.: +1-(306)-966-4193 (C.P.P.); +1-(807)-766-7435 (S.J.L.); Fax: +1-(306)-966-4730 (C.P.P.); +1-(807)-766-7362 (S.J.L.)
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41
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Hannaian SJ, Hodson N, Abou Sawan S, Mazzulla M, Kato H, Matsunaga K, Waskiw-Ford M, Duncan J, Kumbhare DA, Moore DR. Leucine-enriched amino acids maintain peripheral mTOR-Rheb localization independent of myofibrillar protein synthesis and mTORC1 signaling postexercise. J Appl Physiol (1985) 2020; 129:133-143. [PMID: 32525432 DOI: 10.1152/japplphysiol.00241.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Postexercise protein ingestion can elevate rates of myofibrillar protein synthesis (MyoPS), mTORC1 activity, and mTOR translocation/protein-protein interactions. However, it is unclear if leucine-enriched essential amino acids (LEAA) can similarly facilitate intracellular mTOR trafficking in humans after exercise. The purpose of this study was to determine the effect of postexercise LEAA (4 g total EAAs, 1.6 g leucine) on acute MyoPS and mTORC1 translocation and signaling. Recreationally active men performed lower-body resistance exercise (5 × 8-10 leg press and leg extension) to volitional failure. Following exercise participants consumed LEAA (n = 8) or an isocaloric carbohydrate drink (PLA; n = 10). MyoPS was measured over 1.5-4 h of recovery by oral pulse of l-[ring-2H5]-phenylalanine. Phosphorylation of proteins in the mTORC1 pathway were analyzed via immunoblotting and mTORC1-LAMP2/WGA/Rheb colocalization via immunofluorescence microscopy. There was no difference in MyoPS between groups (LEAA = 0.098 ± 0.01%/h; PL = 0.090 ± 0.01%/h; P > 0.05). Exercise increased (P < 0.05) rpS6Ser240/244(LEAA = 35.3-fold; PLA = 20.6-fold), mTORSer2448(LEAA = 1.8-fold; PLA = 1.2-fold) and 4EBP1Thr37/46(LEAA = 1.5-fold; PLA = 1.4-fold) phosphorylation irrespective of nutrition (P > 0.05). LAT1 and SNAT2 protein expression were not affected by exercise or nutrient ingestion. mTOR-LAMP2 colocalization was greater in LEAA preexercise and decreased following exercise and supplement ingestion (P < 0.05), yet was unchanged in PLA. mTOR-WGA (cell periphery marker) and mTOR-Rheb colocalization was greater in LEAA compared with PLA irrespective of time-point (P < 0.05). In conclusion, the postexercise consumption of 4 g of LEAA maintains mTOR in peripheral regions of muscle fibers, in closer proximity to its direct activator Rheb, during prolonged recovery independent of differences in MyoPS or mTORC1 signaling compared with PLA ingestion. This intracellular localization of mTOR may serve to "prime" the kinase for future anabolic stimuli.NEW & NOTEWORTHY This is the first study to investigate whether postexercise leucine-enriched amino acid (LEAA) ingestion elevates mTORC1 translocation and protein-protein interactions in human skeletal muscle. Here, we observed that although LEAA ingestion did not further elevate postexercise MyoPS or mTORC1 signaling compared with placebo, mTORC1 peripheral location and interaction with Rheb were maintained. This may serve to "prime" mTORC1 for subsequent anabolic stimuli.
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Affiliation(s)
- Sarkis J Hannaian
- Faculty of Kinesiology and Physical Education, Department of Exercise Science, University of Toronto, Toronto, Canada
| | - Nathan Hodson
- Faculty of Kinesiology and Physical Education, Department of Exercise Science, University of Toronto, Toronto, Canada
| | - Sidney Abou Sawan
- Faculty of Kinesiology and Physical Education, Department of Exercise Science, University of Toronto, Toronto, Canada
| | - Michael Mazzulla
- Faculty of Kinesiology and Physical Education, Department of Exercise Science, University of Toronto, Toronto, Canada
| | - Hiroyuki Kato
- Technology Development Center, Institute of Food Sciences and Technologies, Ajinomoto Co., Inc., Kawasaki, Kanagawa, Japan
| | - Keiko Matsunaga
- Technology Development Center, Institute of Food Sciences and Technologies, Ajinomoto Co., Inc., Kawasaki, Kanagawa, Japan
| | - Marcus Waskiw-Ford
- Faculty of Kinesiology and Physical Education, Department of Exercise Science, University of Toronto, Toronto, Canada
| | - Justin Duncan
- Faculty of Kinesiology and Physical Education, Department of Exercise Science, University of Toronto, Toronto, Canada
| | | | - Daniel R Moore
- Faculty of Kinesiology and Physical Education, Department of Exercise Science, University of Toronto, Toronto, Canada
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Ajoolabady A, Aghanejad A, Bi Y, Zhang Y, Aslkhodapasandhukmabad H, Abhari A, Ren J. Enzyme-based autophagy in anti-neoplastic management: From molecular mechanisms to clinical therapeutics. Biochim Biophys Acta Rev Cancer 2020; 1874:188366. [PMID: 32339608 DOI: 10.1016/j.bbcan.2020.188366] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/22/2020] [Accepted: 04/22/2020] [Indexed: 02/08/2023]
Abstract
Autophagy is an evolutionarily conserved self-cannibalization process commonly found in all eukaryotic cells. Through autophagy, long-lived or damaged organelles, superfluous proteins, and pathogens are sequestered and encapsulated into the double-membrane autophagosomes prior to fusion with lysosomes for ultimate degradation and recycling. Given that autophagy is deemed both protective and detrimental in malignancies, the clinical therapeutic utilization of autophagy modulators in cancer has attracted immense attentions over the past decades. Dependence of tumor cells on autophagy during amino acid insufficiency or deprivation has prompted us to explore the underlying autophagy regulatory mechanisms to inject amino acid degrading enzymes and enzyme-based strategies into therapeutic maneuvers of autophagy in cancer.
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Affiliation(s)
- Amir Ajoolabady
- Center for Cardiovascular Research and Alternative Medicine, University of Wyoming College of Health Sciences, Laramie, WY 82071, USA; Department of Clinical Biochemistry and Laboratory Medicine, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ayuob Aghanejad
- Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Yaguang Bi
- Shanghai Institute of Cardiovascular Diseases, Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Yingmei Zhang
- Shanghai Institute of Cardiovascular Diseases, Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | | | - Alireza Abhari
- Department of Clinical Biochemistry and Laboratory Medicine, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Jun Ren
- Center for Cardiovascular Research and Alternative Medicine, University of Wyoming College of Health Sciences, Laramie, WY 82071, USA; Shanghai Institute of Cardiovascular Diseases, Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China.
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Groeneweg S, van Geest FS, Peeters RP, Heuer H, Visser WE. Thyroid Hormone Transporters. Endocr Rev 2020; 41:5637505. [PMID: 31754699 DOI: 10.1210/endrev/bnz008] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 11/07/2019] [Indexed: 02/08/2023]
Abstract
Thyroid hormone transporters at the plasma membrane govern intracellular bioavailability of thyroid hormone. Monocarboxylate transporter (MCT) 8 and MCT10, organic anion transporting polypeptide (OATP) 1C1, and SLC17A4 are currently known as transporters displaying the highest specificity toward thyroid hormones. Structure-function studies using homology modeling and mutational screens have led to better understanding of the molecular basis of thyroid hormone transport. Mutations in MCT8 and in OATP1C1 have been associated with clinical disorders. Different animal models have provided insight into the functional role of thyroid hormone transporters, in particular MCT8. Different treatment strategies for MCT8 deficiency have been explored, of which thyroid hormone analogue therapy is currently applied in patients. Future studies may reveal the identity of as-yet-undiscovered thyroid hormone transporters. Complementary studies employing animal and human models will provide further insight into the role of transporters in health and disease. (Endocrine Reviews 41: 1 - 55, 2020).
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Affiliation(s)
- Stefan Groeneweg
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Ferdy S van Geest
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Robin P Peeters
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Heike Heuer
- Department of Endocrinology, Diabetes and Metabolism, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - W Edward Visser
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
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Leucine and mTORc1 act independently to regulate 2-deoxyglucose uptake in L6 myotubes. Amino Acids 2020; 52:477-486. [PMID: 32108266 DOI: 10.1007/s00726-020-02829-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 02/08/2020] [Indexed: 01/15/2023]
Abstract
Chronic mTORc1 hyperactivation via obesity-induced hyperleucinaemia has been implicated in the development of insulin resistance, yet the direct impact of leucine on insulin-stimulated glucose uptake in muscle cells remains unclear. To address this, differentiated L6 myotubes were subjected to various compounds designed to either inhibit mTORc1 activity (rapamycin), blunt leucine intracellular import (BCH), or activate mTORc1 signalling (3BDO), prior to the determination of the uptake of the glucose analogue, 2-deoxyglucose (2-DG), in response to 1 mM insulin. In separate experiments, L6 myotubes were subject to various media concentrations of leucine (0-0.8 mM) for 24 h before 2-DG uptake in response to insulin was assessed. Both rapamycin and BCH blunted 2-DG uptake, irrespective of insulin administration, and this occurred in parallel with a decline in mTOR, 4E-BP1, and p70S6K phosphorylation status, but little effect on AKT phosphorylation. In contrast, reducing leucine media concentrations suppressed 2-DG uptake, both under insulin- and non-insulin-stimulated conditions, but did not alter the phosphorylation state of AKT-mTORc1 components examined. Unexpectedly, 3BDO failed to stimulate mTORc1 signalling, but, nonetheless, caused a significant increase in 2-DG uptake under non-insulin-stimulated conditions. Both leucine and mTORc1 influence glucose uptake in muscle cells independent of insulin administration, and this likely occurs via distinct but overlapping mechanisms.
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Poncet N, Halley PA, Lipina C, Gierliński M, Dady A, Singer GA, Febrer M, Shi Y, Yamaguchi TP, Taylor PM, Storey KG. Wnt regulates amino acid transporter Slc7a5 and so constrains the integrated stress response in mouse embryos. EMBO Rep 2020; 21:e48469. [PMID: 31789450 PMCID: PMC6944906 DOI: 10.15252/embr.201948469] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 10/18/2019] [Accepted: 10/25/2019] [Indexed: 12/29/2022] Open
Abstract
Amino acids are essential for cellular metabolism, and it is important to understand how nutrient supply is coordinated with changing energy requirements during embryogenesis. Here, we show that the amino acid transporter Slc7a5/Lat1 is highly expressed in tissues undergoing morphogenesis and that Slc7a5-null mouse embryos have profound neural and limb bud outgrowth defects. Slc7a5-null neural tissue exhibited aberrant mTORC1 activity and cell proliferation; transcriptomics, protein phosphorylation and apoptosis analyses further indicated induction of the integrated stress response as a potential cause of observed defects. The pattern of stress response gene expression induced in Slc7a5-null embryos was also detected at low level in wild-type embryos and identified stress vulnerability specifically in tissues undergoing morphogenesis. The Slc7a5-null phenotype is reminiscent of Wnt pathway mutants, and we show that Wnt/β-catenin loss inhibits Slc7a5 expression and induces this stress response. Wnt signalling therefore normally supports the metabolic demands of morphogenesis and constrains cellular stress. Moreover, operation in the embryo of the integrated stress response, which is triggered by pathogen-mediated as well as metabolic stress, may provide a mechanistic explanation for a range of developmental defects.
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Affiliation(s)
- Nadège Poncet
- Division of Cell & Developmental BiologySchool of Life SciencesUniversity of DundeeDundeeUK
- Present address:
Institute of PhysiologyUniversity of ZürichZürichSwitzerland
| | - Pamela A Halley
- Division of Cell & Developmental BiologySchool of Life SciencesUniversity of DundeeDundeeUK
| | - Christopher Lipina
- Division of Cell Signalling and ImmunologySchool of Life SciencesUniversity of DundeeDundeeUK
| | - Marek Gierliński
- Division of Computational BiologySchool of Life SciencesUniversity of DundeeDundeeUK
| | - Alwyn Dady
- Division of Cell & Developmental BiologySchool of Life SciencesUniversity of DundeeDundeeUK
| | - Gail A Singer
- Division of Cell & Developmental BiologySchool of Life SciencesUniversity of DundeeDundeeUK
| | - Melanie Febrer
- Sequencing FacilitySchool of Life SciencesUniversity of DundeeDundeeUK
- Present address:
Illumina CanadaVictoriaBCCanada
| | - Yun‐Bo Shi
- Section on Molecular MorphogenesisNICHD, NIHBethesdaMDUSA
| | - Terry P Yamaguchi
- Cancer and Developmental Biology LaboratoryCenter for Cancer ResearchNational Cancer Institute‐Frederick, NIHFrederickMDUSA
| | - Peter M Taylor
- Division of Cell Signalling and ImmunologySchool of Life SciencesUniversity of DundeeDundeeUK
| | - Kate G Storey
- Division of Cell & Developmental BiologySchool of Life SciencesUniversity of DundeeDundeeUK
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Lu X. The Role of Large Neutral Amino Acid Transporter (LAT1) in Cancer. Curr Cancer Drug Targets 2019; 19:863-876. [DOI: 10.2174/1568009619666190802135714] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 05/24/2019] [Accepted: 05/31/2019] [Indexed: 12/11/2022]
Abstract
Background:
The solute carrier family 7 (SLC7) can be categorically divided into two
subfamilies, the L-type amino acid transporters (LATs) including SLC7A5-13, and SLC7A15, and
the cationic amino acid transporters (CATs) including SLC7A1-4 and SLC7A14. Members of the
CAT family transport predominantly cationic amino acids by facilitating diffusion with intracellular
substrates. LAT1 (also known as SLC7A5), is defined as a heteromeric amino acid transporter
(HAT) interacting with the glycoprotein CD98 (SLC3A2) through a conserved disulfide to uptake
not only large neutral amino acids, but also several pharmaceutical drugs to cells.
Methods:
In this review, we provide an overview of the interaction of the structure-function of
LAT1 and its essential role in cancer, specifically, its role at the blood-brain barrier (BBB) to facilitate
the transport of thyroid hormones, pharmaceuticals (e.g., I-DOPA, gabapentin), and metabolites
into the brain.
Results:
LAT1 expression increases as cancers progress, leading to higher expression levels in highgrade
tumors and metastases. In addition, LAT1 plays a crucial role in cancer-associated
reprogrammed metabolic networks by supplying tumor cells with essential amino acids.
Conclusion:
The increasing understanding of the role of LAT1 in cancer has led to an increase in
interest surrounding its potential as a drug target for cancer treatment.
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Affiliation(s)
- Xinjie Lu
- The Mary and Garry Weston Molecular Immunology Laboratory, Thrombosis Research Institute, London, SW3 6LR, United Kingdom
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47
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Nasrallah P, Haidar EA, Stephan JS, El Hayek L, Karnib N, Khalifeh M, Barmo N, Jabre V, Houbeika R, Ghanem A, Nasser J, Zeeni N, Bassil M, Sleiman SF. Branched-chain amino acids mediate resilience to chronic social defeat stress by activating BDNF/TRKB signaling. Neurobiol Stress 2019; 11:100170. [PMID: 31193350 PMCID: PMC6526306 DOI: 10.1016/j.ynstr.2019.100170] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/10/2019] [Accepted: 05/11/2019] [Indexed: 02/07/2023] Open
Abstract
How individuals respond to chronic stress varies. Susceptible individuals ultimately develop depression; whereas resilient individuals live normally. In this study, our objective was to examine the effect of branched-chain amino acids (BCAA), commonly used by athletes, on susceptibility to stress. Male C57BL/6 mice were subjected to daily defeat sessions by a CD1 aggressor, for 10 days. On day11, the behavior of mice was assessed using the social interaction test, elevated plus maze and open field. Mice received the BCAA leucine, isoleucine or valine before each defeat session. Furthermore, we examined whether BCAA regulate brain derived neurotrophic factor (BDNF) signaling by using a brain-permeable tropomyosin receptor kinase B (TRKB) inhibitor, ANA-12. We also tested the effect of voluntary exercise and high protein diets on susceptibility to stress. Mice exposed to chronic stress displayed increased susceptibility and social avoidance. BCAA promoted resilience to chronic stress, rescued social avoidance behaviors and increased hippocampal BDNF levels and TRKB activation. Inhibition of TRKB signaling abolished the ability of BCAA to promote resilience to stress and to rescue social avoidance. Interestingly, we found that BCAA activate the exercise-regulated PGC1a/FNDC5 pathway known to induce hippocampal BDNF signaling. Although both voluntary exercise and BCAA promoted resilience to stress, combining them did not yield synergistic effects confirming that they affect similar pathways. We also discovered that high protein diets mimic the effect of BCAA by rescuing social deficits induced by chronic stress and increase Bdnf expression in the hippocampus. Our data indicate that BCAA, exercise and high protein diets rescue susceptibility to stress by activating the hippocampal BDNF/TRKB signaling.
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Affiliation(s)
- Patrick Nasrallah
- Biology Program, Department of Natural Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Edwina Abou Haidar
- Molecular Biology Program, Department of Natural Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Joseph S. Stephan
- School of Medicine, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Lauretta El Hayek
- Molecular Biology Program, Department of Natural Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Nabil Karnib
- Molecular Biology Program, Department of Natural Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Mohamad Khalifeh
- Molecular Biology Program, Department of Natural Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Nour Barmo
- Molecular Biology Program, Department of Natural Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Vanessa Jabre
- Molecular Biology Program, Department of Natural Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Rouba Houbeika
- Biology Program, Department of Natural Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Anthony Ghanem
- Biology Program, Department of Natural Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Jason Nasser
- Biology Program, Department of Natural Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Nadine Zeeni
- Nutrition Program, Department of Natural Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Maya Bassil
- Nutrition Program, Department of Natural Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Sama F. Sleiman
- Biology Program, Department of Natural Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
- Molecular Biology Program, Department of Natural Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
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48
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Liu F, Csetenyi L, Gadd GM. Amino acid secretion influences the size and composition of copper carbonate nanoparticles synthesized by ureolytic fungi. Appl Microbiol Biotechnol 2019; 103:7217-7230. [PMID: 31289902 PMCID: PMC6691030 DOI: 10.1007/s00253-019-09961-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 05/31/2019] [Accepted: 06/01/2019] [Indexed: 11/30/2022]
Abstract
The ureolytic activity of Neurospora crassa results in an alkaline carbonate-rich culture medium which can precipitate soluble metals as insoluble carbonates. Such carbonates are smaller, often of nanoscale dimensions, than metal carbonates synthesized abiotically which infers that fungal excreted products can markedly affect particle size. In this work, it was found that amino acid excretion was a significant factor in affecting the particle size of copper carbonate. Eleven different amino acids were found to be secreted by Neurospora crassa, and L-glutamic acid, L-aspartic acid and L-cysteine were chosen to examine the impact of amino acids on the morphology and chemical composition of copper carbonate minerals. X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) were used to characterize the obtained copper carbonate samples. Copper carbonate nanoparticles with a diameter of 100-200 nm were produced with L-glutamic acid, and the presence of L-glutamic acid was found to stabilize these particles in the early phase of crystal growth and prevent them from aggregation. FTIR and TG analysis revealed that the amino acid moieties were intimately associated with the copper mineral particles. Component analysis of the final products of TG analysis of the copper minerals synthesized under various conditions showed the ultimate formation of Cu, Cu2O and Cu2S, suggesting a novel synthesis method for producing these useful Cu-containing materials.
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Affiliation(s)
- Feixue Liu
- Geomicrobiology Group, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, UK
| | - Laszlo Csetenyi
- Concrete Technology Group, Department of Civil Engineering, University of Dundee, Dundee, DD1 4HN, Scotland, UK
| | - Geoffrey Michael Gadd
- Geomicrobiology Group, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, UK.
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49
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Ozaki K, Yamada T, Horie T, Ishizaki A, Hiraiwa M, Iezaki T, Park G, Fukasawa K, Kamada H, Tokumura K, Motono M, Kaneda K, Ogawa K, Ochi H, Sato S, Kobayashi Y, Shi YB, Taylor PM, Hinoi E. The L-type amino acid transporter LAT1 inhibits osteoclastogenesis and maintains bone homeostasis through the mTORC1 pathway. Sci Signal 2019; 12:12/589/eaaw3921. [PMID: 31289211 DOI: 10.1126/scisignal.aaw3921] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
L-type amino acid transporter 1 (LAT1), which is encoded by solute carrier transporter 7a5 (Slc7a5), plays a crucial role in amino acid sensing and signaling in specific cell types, contributing to the pathogenesis of cancer and neurological disorders. Amino acid substrates of LAT1 have a beneficial effect on bone health directly and indirectly, suggesting a potential role for LAT1 in bone homeostasis. Here, we identified LAT1 in osteoclasts as important for bone homeostasis. Slc7a5 expression was substantially reduced in osteoclasts in a mouse model of ovariectomy-induced osteoporosis. The osteoclast-specific deletion of Slc7a5 in mice led to osteoclast activation and bone loss in vivo, and Slc7a5 deficiency increased osteoclastogenesis in vitro. Loss of Slc7a5 impaired activation of the mechanistic target of rapamycin complex 1 (mTORC1) pathway in osteoclasts, whereas genetic activation of mTORC1 corrected the enhanced osteoclastogenesis and bone loss in Slc7a5-deficient mice. Last, Slc7a5 deficiency increased the expression of nuclear factor of activated T cells, cytoplasmic 1 (Nfatc1) and the nuclear accumulation of NFATc1, a master regulator of osteoclast function, possibly through the canonical nuclear factor κB pathway and the Akt-glycogen synthase kinase 3β signaling axis, respectively. These findings suggest that the LAT1-mTORC1 axis plays a pivotal role in bone resorption and bone homeostasis by modulating NFATc1 in osteoclasts, thereby providing a molecular connection between amino acid intake and skeletal integrity.
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Affiliation(s)
- Kakeru Ozaki
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Takanori Yamada
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Tetsuhiro Horie
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Atsushi Ishizaki
- Laboratory of Clinical Analytical Sciences, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Manami Hiraiwa
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Takashi Iezaki
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan.,Venture Business Laboratory, Organization of Frontier Science and Innovation, Kanazawa University, Kanazawa, Ishikawa 920-1192, Japan
| | - Gyujin Park
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Kazuya Fukasawa
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Hikari Kamada
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Kazuya Tokumura
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Mei Motono
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Katsuyuki Kaneda
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Kazuma Ogawa
- Laboratory of Clinical Analytical Sciences, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan.,Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Ishikawa 920-1192, Japan
| | - Hiroki Ochi
- Department of Physiology and Cell Biology, Tokyo Medical and Dental University, Graduate School, Tokyo 113-8510, Japan
| | - Shingo Sato
- Department of Physiology and Cell Biology, Tokyo Medical and Dental University, Graduate School, Tokyo 113-8510, Japan
| | - Yasuhiro Kobayashi
- Institute for Oral Science, Matsumoto Dental University, Shiojiri, Nagano 399-0781, Japan
| | - Yun-Bo Shi
- Section on Molecular Morphogenesis, Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Peter M Taylor
- Division of Cell Signalling and Immunology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Eiichi Hinoi
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan.
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50
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Katada T, Sakurai H. Xenopus slc7a5 is essential for notochord function and eye development. Mech Dev 2019; 155:48-59. [DOI: 10.1016/j.mod.2019.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 12/26/2018] [Accepted: 01/03/2019] [Indexed: 10/27/2022]
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