101
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Wang Z, Duan Y, Li F, Yang B, Zhang J, Hou S. Dietary supplementation with Lonicera macranthoides leaf powder enhances growth performance and muscle growth of Chinese Tibetan pigs. Livest Sci 2017. [DOI: 10.1016/j.livsci.2017.09.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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102
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Zhou H, Yu B, Gao J, Htoo JK, Chen D. Regulation of intestinal health by branched-chain amino acids. Anim Sci J 2017; 89:3-11. [PMID: 29164733 DOI: 10.1111/asj.12937] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 09/11/2017] [Indexed: 12/15/2022]
Abstract
Besides its primary role in the digestion and absorption of nutrients, the intestine also interacts with a complex external milieu, and is the first defense line against noxious pathogens and antigens. Dysfunction of the intestinal barrier is associated with enhanced intestinal permeability and development of various gastrointestinal diseases. The branched-chain amino acids (BCAAs) are important nutrients, which are the essential substrates for protein biosynthesis. Recently, emerging evidence showed that BCAAs are involved in maintaining intestinal barrier function. It has been reported that dietary supplementation with BCAAs promotes intestinal development, enhances enterocyte proliferation, increases intestinal absorption of amino acids (AA) and glucose, and improves the immune defenses of piglets. The underlying mechanism of these effects is mediated by regulating expression of genes and proteins associate with various signaling pathways. In addition, BCAAs promote the production of beneficial bacteria in the intestine of mice. Compelling evidence supports the notion that BCAAs play important roles in both nutrition and intestinal health. Therefore, as functional amino acids with various physiological effects, BCAAs hold key roles in promoting intestinal development and health in animals and humans.
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Affiliation(s)
- Hua Zhou
- Institute of Animal Nutrition, Sichuan Agricultural University, Ya'an, China
| | - Bing Yu
- Institute of Animal Nutrition, Sichuan Agricultural University, Ya'an, China
| | - Jun Gao
- Evonik Degussa (China) Co. Ltd., Beijing, China
| | | | - Daiwen Chen
- Institute of Animal Nutrition, Sichuan Agricultural University, Ya'an, China
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103
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Wyant GA, Abu-Remaileh M, Wolfson RL, Chen WW, Freinkman E, Danai LV, Vander Heiden MG, Sabatini DM. mTORC1 Activator SLC38A9 Is Required to Efflux Essential Amino Acids from Lysosomes and Use Protein as a Nutrient. Cell 2017; 171:642-654.e12. [PMID: 29053970 DOI: 10.1016/j.cell.2017.09.046] [Citation(s) in RCA: 302] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 07/18/2017] [Accepted: 09/25/2017] [Indexed: 12/17/2022]
Abstract
The mTORC1 kinase is a master growth regulator that senses many environmental cues, including amino acids. Activation of mTORC1 by arginine requires SLC38A9, a poorly understood lysosomal membrane protein with homology to amino acid transporters. Here, we validate that SLC38A9 is an arginine sensor for the mTORC1 pathway, and we uncover an unexpectedly central role for SLC38A9 in amino acid homeostasis. SLC38A9 mediates the transport, in an arginine-regulated fashion, of many essential amino acids out of lysosomes, including leucine, which mTORC1 senses through the cytosolic Sestrin proteins. SLC38A9 is necessary for leucine generated via lysosomal proteolysis to exit lysosomes and activate mTORC1. Pancreatic cancer cells, which use macropinocytosed protein as a nutrient source, require SLC38A9 to form tumors. Thus, through SLC38A9, arginine serves as a lysosomal messenger that couples mTORC1 activation to the release from lysosomes of the essential amino acids needed to drive cell growth.
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Affiliation(s)
- Gregory A Wyant
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Monther Abu-Remaileh
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Rachel L Wolfson
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA; Harvard Medical School M.D.-Ph.D. Program, Daniel C. Tosteson Medical Education Center, 260 Longwood Avenue, Boston, MA 02115, USA
| | - Walter W Chen
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA; Harvard Medical School M.D.-Ph.D. Program, Daniel C. Tosteson Medical Education Center, 260 Longwood Avenue, Boston, MA 02115, USA
| | - Elizaveta Freinkman
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA
| | - Laura V Danai
- Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Matthew G Vander Heiden
- Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA; Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA.
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104
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Usuki F, Fujimura M, Yamashita A. Endoplasmic reticulum stress preconditioning modifies intracellular mercury content by upregulating membrane transporters. Sci Rep 2017; 7:12390. [PMID: 28959040 PMCID: PMC5620048 DOI: 10.1038/s41598-017-09435-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 07/27/2017] [Indexed: 01/02/2023] Open
Abstract
Endoplasmic reticulum (ER) stress preconditioning protects cells against methylmercury (MeHg) cytotoxicity by inducing integrated stress responses such as eIF2α phosphorylation, ATF4 accumulation, and nonsense-mediated mRNA decay (NMD) suppression. Here we demonstrated that ER stress preconditioning results in the upregulation of membrane transporters, leading to a decrease in intracellular mercury content. Our analyses showed that ER stress preconditioning upregulated the expression of methionine transporters that affect the cellular influx of MeHg, LAT1, LAT3, and SNAT2; and a membrane transporter that affects the efflux of MeHg, ABCC4, in MeHg-susceptible myogenic cells. Among these, ABCC4 transporter expression exhibited the greatest elevation. The functional significance of ABCC4 transporter in the efflux of MeHg was shown by the ABCC4 inhibition study. Additionally, we identified the role of phospho-eIF2α/ATF4 pathway in the upregulation of LAT1, SNAT2, and ABCC4 and the role of NMD suppression in LAT3 upregulation. Further, we detected that ER stress preconditioning amplified membrane transporter expression most likely through the translation of the upregulated mRNAs caused by ATF4-dependent transcription and NMD suppression. Taken together, these results suggested that the phospho-eIF2α/ATF4 pathway activation and NMD suppression may represent therapeutic targets for the alleviation of MeHg cytotoxicity by enhancing mercury efflux besides inducing protective stress responses.
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Affiliation(s)
- Fusako Usuki
- Department of Clinical Medicine, National Institute for Minamata Disease, Kumamoto, 867-0008, Japan.
| | - Masatake Fujimura
- Department of Basic Medical Sciences, National Institute for Minamata Disease, Kumamoto, 867-0008, Japan
| | - Akio Yamashita
- Department of Molecular Biology, Yokohama City University School of Medicine, Yokohama, 236-0004, Japan
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105
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Leucine reduces reactive oxygen species levels via an energy metabolism switch by activation of the mTOR-HIF-1α pathway in porcine intestinal epithelial cells. Int J Biochem Cell Biol 2017; 89:42-56. [DOI: 10.1016/j.biocel.2017.05.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 05/23/2017] [Accepted: 05/24/2017] [Indexed: 12/20/2022]
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106
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Stryeck S, Birner-Gruenberger R, Madl T. Integrative metabolomics as emerging tool to study autophagy regulation. MICROBIAL CELL (GRAZ, AUSTRIA) 2017; 4:240-258. [PMID: 28845422 PMCID: PMC5568430 DOI: 10.15698/mic2017.08.584] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 07/01/2017] [Indexed: 12/15/2022]
Abstract
Recent technological developments in metabolomics research have enabled in-depth characterization of complex metabolite mixtures in a wide range of biological, biomedical, environmental, agricultural, and nutritional research fields. Nuclear magnetic resonance spectroscopy and mass spectrometry are the two main platforms for performing metabolomics studies. Given their broad applicability and the systemic insight into metabolism that can be obtained it is not surprising that metabolomics becomes increasingly popular in basic biological research. In this review, we provide an overview on key metabolites, recent studies, and future opportunities for metabolomics in studying autophagy regulation. Metabolites play a pivotal role in autophagy regulation and are therefore key targets for autophagy research. Given the recent success of metabolomics, it can be expected that metabolomics approaches will contribute significantly to deciphering the complex regulatory mechanisms involved in autophagy in the near future and promote understanding of autophagy and autophagy-related diseases in living cells and organisms.
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Affiliation(s)
- Sarah Stryeck
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, 8010 Graz, Austria
| | - Ruth Birner-Gruenberger
- Research Unit for Functional Proteomics and Metabolic Pathways, Institute of Pathology, Medical University of Graz, 8010 Graz, Austria
| | - Tobias Madl
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, 8010 Graz, Austria
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107
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Julliard AK, Al Koborssy D, Fadool DA, Palouzier-Paulignan B. Nutrient Sensing: Another Chemosensitivity of the Olfactory System. Front Physiol 2017; 8:468. [PMID: 28747887 PMCID: PMC5506222 DOI: 10.3389/fphys.2017.00468] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 06/19/2017] [Indexed: 12/31/2022] Open
Abstract
Olfaction is a major sensory modality involved in real time perception of the chemical composition of the external environment. Olfaction favors anticipation and rapid adaptation of behavioral responses necessary for animal survival. Furthermore, recent studies have demonstrated that there is a direct action of metabolic peptides on the olfactory network. Orexigenic peptides such as ghrelin and orexin increase olfactory sensitivity, which in turn, is decreased by anorexigenic hormones such as insulin and leptin. In addition to peptides, nutrients can play a key role on neuronal activity. Very little is known about nutrient sensing in olfactory areas. Nutrients, such as carbohydrates, amino acids, and lipids, could play a key role in modulating olfactory sensitivity to adjust feeding behavior according to metabolic need. Here we summarize recent findings on nutrient-sensing neurons in olfactory areas and delineate the limits of our knowledge on this topic. The present review opens new lines of investigations on the relationship between olfaction and food intake, which could contribute to determining the etiology of metabolic disorders.
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Affiliation(s)
- A-Karyn Julliard
- Univ Lyon, Université Claude Bernard Lyon1, Centre de Recherche en Neurosciences de Lyon (CRNL), INSERM U1028/Centre National de la Recherche Scientifique UMR5292 Team Olfaction: From Coding to MemoryLyon, France
| | - Dolly Al Koborssy
- Department of Biological Science, Florida State UniversityTallahassee, FL, United States.,Program in Neuroscience, Florida State UniversityTallahassee, FL, United States
| | - Debra A Fadool
- Department of Biological Science, Florida State UniversityTallahassee, FL, United States.,Program in Neuroscience, Florida State UniversityTallahassee, FL, United States.,Institute of Molecular Biophysics, Florida State UniversityTallahassee, FL, United States
| | - Brigitte Palouzier-Paulignan
- Univ Lyon, Université Claude Bernard Lyon1, Centre de Recherche en Neurosciences de Lyon (CRNL), INSERM U1028/Centre National de la Recherche Scientifique UMR5292 Team Olfaction: From Coding to MemoryLyon, France
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108
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Dinkeloo K, Boyd S, Pilot G. Update on amino acid transporter functions and on possible amino acid sensing mechanisms in plants. Semin Cell Dev Biol 2017; 74:105-113. [PMID: 28705659 DOI: 10.1016/j.semcdb.2017.07.010] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 06/30/2017] [Accepted: 07/07/2017] [Indexed: 12/25/2022]
Abstract
Amino acids are essential components of plant metabolism, not only as constituents of proteins, but also as precursors of important secondary metabolites and as carriers of organic nitrogen between the organs of the plant. Transport across intracellular membranes and translocation of amino acids within the plant is mediated by membrane amino acid transporters. The past few years have seen the identification of a new family of amino acid transporters in Arabidopsis, the characterization of intracellular amino acid transporters, and the discovery of new roles for already known proteins. While amino acid metabolism needs to be tightly coordinated with amino acid transport activity and carbohydrate metabolism, no gene involved in amino acid sensing in plants has been unequivocally identified to date. This review aims at summarizing the recent data accumulated on the identity and function of amino acid transporters in plants, and discussing the possible identity of amino acid sensors based on data from other organisms.
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Affiliation(s)
- Kasia Dinkeloo
- Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA 24060, USA
| | - Shelton Boyd
- Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA 24060, USA
| | - Guillaume Pilot
- Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA 24060, USA.
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109
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Kishida K, Pearce SC, Yu S, Gao N, Ferraris RP. Nutrient sensing by absorptive and secretory progenies of small intestinal stem cells. Am J Physiol Gastrointest Liver Physiol 2017; 312:G592-G605. [PMID: 28336548 PMCID: PMC5495913 DOI: 10.1152/ajpgi.00416.2016] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 03/15/2017] [Accepted: 03/16/2017] [Indexed: 01/31/2023]
Abstract
Nutrient sensing triggers responses by the gut-brain axis modulating hormone release, feeding behavior and metabolism that become dysregulated in metabolic syndrome and some cancers. Except for absorptive enterocytes and secretory enteroendocrine cells, the ability of many intestinal cell types to sense nutrients is still unknown; hence we hypothesized that progenitor stem cells (intestinal stem cells, ISC) possess nutrient sensing ability inherited by progenies during differentiation. We directed via modulators of Wnt and Notch signaling differentiation of precursor mouse intestinal crypts into specialized organoids each containing ISC, enterocyte, goblet, or Paneth cells at relative proportions much higher than in situ as determined by mRNA expression and immunocytochemistry of cell type biomarkers. We identified nutrient sensing cell type(s) by increased expression of fructolytic genes in response to a fructose challenge. Organoids comprised primarily of enterocytes, Paneth, or goblet, but not ISC, cells responded specifically to fructose without affecting nonfructolytic genes. Sensing was independent of Wnt and Notch modulators and of glucose concentrations in the medium but required fructose absorption and metabolism. More mature enterocyte- and goblet-enriched organoids exhibited stronger fructose responses. Remarkably, enterocyte organoids, upon forced dedifferentiation to reacquire ISC characteristics, exhibited a markedly extended lifespan and retained fructose sensing ability, mimicking responses of some dedifferentiated cancer cells. Using an innovative approach, we discovered that nutrient sensing is likely repressed in progenitor ISCs then irreversibly derepressed during specification into sensing-competent absorptive or secretory lineages, the surprising capacity of Paneth and goblet cells to detect fructose, and the important role of differentiation in modulating nutrient sensing.NEW & NOTEWORTHY Small intestinal stem cells differentiate into several cell types transiently populating the villi. We used specialized organoid cultures each comprised of a single cell type to demonstrate that 1) differentiation seems required for nutrient sensing, 2) secretory goblet and Paneth cells along with enterocytes sense fructose, suggesting that sensing is acquired after differentiation is triggered but before divergence between absorptive and secretory lineages, and 3) forcibly dedifferentiated enterocytes exhibit fructose sensing and lifespan extension.
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Affiliation(s)
- Kunihiro Kishida
- 1Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, Newark, New Jersey; and
| | - Sarah C. Pearce
- 1Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, Newark, New Jersey; and
| | - Shiyan Yu
- 2Department of Biological Sciences, Life Science Center, Rutgers University, Newark, New Jersey
| | - Nan Gao
- 2Department of Biological Sciences, Life Science Center, Rutgers University, Newark, New Jersey
| | - Ronaldo P. Ferraris
- 1Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, Newark, New Jersey; and
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110
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Amino acid homeostasis and signalling in mammalian cells and organisms. Biochem J 2017; 474:1935-1963. [PMID: 28546457 PMCID: PMC5444488 DOI: 10.1042/bcj20160822] [Citation(s) in RCA: 306] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/08/2017] [Accepted: 03/10/2017] [Indexed: 12/19/2022]
Abstract
Cells have a constant turnover of proteins that recycle most amino acids over time. Net loss is mainly due to amino acid oxidation. Homeostasis is achieved through exchange of essential amino acids with non-essential amino acids and the transfer of amino groups from oxidised amino acids to amino acid biosynthesis. This homeostatic condition is maintained through an active mTORC1 complex. Under amino acid depletion, mTORC1 is inactivated. This increases the breakdown of cellular proteins through autophagy and reduces protein biosynthesis. The general control non-derepressable 2/ATF4 pathway may be activated in addition, resulting in transcription of genes involved in amino acid transport and biosynthesis of non-essential amino acids. Metabolism is autoregulated to minimise oxidation of amino acids. Systemic amino acid levels are also tightly regulated. Food intake briefly increases plasma amino acid levels, which stimulates insulin release and mTOR-dependent protein synthesis in muscle. Excess amino acids are oxidised, resulting in increased urea production. Short-term fasting does not result in depletion of plasma amino acids due to reduced protein synthesis and the onset of autophagy. Owing to the fact that half of all amino acids are essential, reduction in protein synthesis and amino acid oxidation are the only two measures to reduce amino acid demand. Long-term malnutrition causes depletion of plasma amino acids. The CNS appears to generate a protein-specific response upon amino acid depletion, resulting in avoidance of an inadequate diet. High protein levels, in contrast, contribute together with other nutrients to a reduction in food intake.
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111
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The effects of reduced dietary protein level on amino acid transporters and mTOR signaling pathway in pigs. Biochem Biophys Res Commun 2017; 485:319-327. [DOI: 10.1016/j.bbrc.2017.02.084] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 02/16/2017] [Indexed: 12/17/2022]
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112
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Shang P, Valapala M, Grebe R, Hose S, Ghosh S, Bhutto IA, Handa JT, Lutty GA, Lu L, Wan J, Qian J, Sergeev Y, Puertollano R, Zigler JS, Xu GT, Sinha D. The amino acid transporter SLC36A4 regulates the amino acid pool in retinal pigmented epithelial cells and mediates the mechanistic target of rapamycin, complex 1 signaling. Aging Cell 2017; 16:349-359. [PMID: 28083894 PMCID: PMC5334531 DOI: 10.1111/acel.12561] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2016] [Indexed: 12/14/2022] Open
Abstract
The dry (nonneovascular) form of age‐related macular degeneration (AMD), a leading cause of blindness in the elderly, has few, if any, treatment options at present. It is characterized by early accumulation of cellular waste products in the retinal pigmented epithelium (RPE); rejuvenating impaired lysosome function in RPE is a well‐justified target for treatment. It is now clear that amino acids and vacuolar‐type H+‐ATPase (V‐ATPase) regulate the mechanistic target of rapamycin, complex 1 (mTORC1) signaling in lysosomes. Here, we provide evidence for the first time that the amino acid transporter SLC36A4/proton‐dependent amino acid transporter (PAT4) regulates the amino acid pool in the lysosomes of RPE. In Cryba1 (gene encoding βA3/A1‐crystallin) KO (knockout) mice, where PAT4 and amino acid levels are increased in the RPE, the transcription factors EB (TFEB) and E3 (TFE3) are retained in the cytoplasm, even after 24 h of fasting. Consequently, genes in the coordinated lysosomal expression and regulation (CLEAR) network are not activated, and lysosomal function remains low. As these mice age, expression of RPE65 and lecithin retinol acyltransferase (LRAT), two vital visual cycle proteins, decreases in the RPE. A defective visual cycle would possibly slow down the regeneration of new photoreceptor outer segments (POS). Further, photoreceptor degeneration also becomes obvious during aging, reminiscent of human dry AMD disease. Electron microscopy shows basal laminar deposits in Bruch's membrane, a hallmark of development of AMD. For dry AMD patients, targeting PAT4/V‐ATPase in the lysosomes of RPE cells may be an effective means of preventing or delaying disease progression.
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Affiliation(s)
- Peng Shang
- Department of Ophthalmology of Shanghai Tenth People's Hospital and Laboratory of Clinical Visual Science of Tongji Eye Institute; Tongji University School of Medicine; Shanghai China
- The Wilmer Eye Institute; The Johns Hopkins University School of Medicine; Baltimore MD USA
| | - Mallika Valapala
- The Wilmer Eye Institute; The Johns Hopkins University School of Medicine; Baltimore MD USA
| | - Rhonda Grebe
- The Wilmer Eye Institute; The Johns Hopkins University School of Medicine; Baltimore MD USA
| | - Stacey Hose
- The Wilmer Eye Institute; The Johns Hopkins University School of Medicine; Baltimore MD USA
| | - Sayan Ghosh
- The Wilmer Eye Institute; The Johns Hopkins University School of Medicine; Baltimore MD USA
| | - Imran A. Bhutto
- The Wilmer Eye Institute; The Johns Hopkins University School of Medicine; Baltimore MD USA
| | - James T. Handa
- The Wilmer Eye Institute; The Johns Hopkins University School of Medicine; Baltimore MD USA
| | - Gerard A. Lutty
- The Wilmer Eye Institute; The Johns Hopkins University School of Medicine; Baltimore MD USA
| | - Lixia Lu
- Department of Ophthalmology of Shanghai Tenth People's Hospital and Laboratory of Clinical Visual Science of Tongji Eye Institute; Tongji University School of Medicine; Shanghai China
| | - Jun Wan
- The Wilmer Eye Institute; The Johns Hopkins University School of Medicine; Baltimore MD USA
| | - Jiang Qian
- The Wilmer Eye Institute; The Johns Hopkins University School of Medicine; Baltimore MD USA
| | - Yuri Sergeev
- National Eye Institute; National Institutes of Health; Bethesda MD USA
| | - Rosa Puertollano
- Cell Biology and Physiology Center; National Heart, Lung and Blood Institute; National Institutes of Health; Bethesda MD USA
| | - J. Samuel Zigler
- The Wilmer Eye Institute; The Johns Hopkins University School of Medicine; Baltimore MD USA
| | - Guo-Tong Xu
- Department of Ophthalmology of Shanghai Tenth People's Hospital and Laboratory of Clinical Visual Science of Tongji Eye Institute; Tongji University School of Medicine; Shanghai China
- Translational Medical Center for Stem Cell Therapy; Shanghai East Hospital; Tongji University School of Medicine; Shanghai China
- The Collaborative Innovation Center for Brain Science; Tongji University; Shanghai China
| | - Debasish Sinha
- The Wilmer Eye Institute; The Johns Hopkins University School of Medicine; Baltimore MD USA
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113
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Hellsten SV, Eriksson MM, Lekholm E, Arapi V, Perland E, Fredriksson R. The gene expression of the neuronal protein, SLC38A9, changes in mouse brain after in vivo starvation and high-fat diet. PLoS One 2017; 12:e0172917. [PMID: 28235079 PMCID: PMC5325605 DOI: 10.1371/journal.pone.0172917] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 02/03/2017] [Indexed: 11/18/2022] Open
Abstract
SLC38A9 is characterized as a lysosomal component of the amino acid sensing Ragulator-RAG GTPase complex, controlling the mechanistic target of rapamycin complex 1 (mTORC1). Here, immunohistochemistry was used to map SLC38A9 in mouse brain and staining was detected throughout the brain, in cortex, hypothalamus, thalamus, hippocampus, brainstem and cerebellum. More specifically, immunostaining was found in areas known to be involved in amino acid sensing and signaling pathways e.g. piriform cortex and hypothalamus. SLC38A9 immunoreactivity co-localized with both GABAergic and glutamatergic neurons, but not with astrocytes. SLC38A9 play a key role in the mTORC1 pathway, and therefore we performed in vivo starvation and high-fat diet studies, to measure gene expression alterations in specific brain tissues and in larger brain regions. Following starvation, Slc38a9 was upregulated in brainstem and cortex, and in anterior parts of the brain (Bregma 3.2 to -2.1mm). After high-fat diet, Slc38a9 was specifically upregulated in hypothalamus, while overall downregulation was noticed throughout the brain (Bregma 3.2 to -8.6mm).
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Affiliation(s)
- Sofie V. Hellsten
- Department of Pharmaceutical Bioscience, Molecular Neuropharmacology, Uppsala University, Uppsala SE, Sweden
- * E-mail:
| | - Mikaela M. Eriksson
- Department of Pharmaceutical Bioscience, Molecular Neuropharmacology, Uppsala University, Uppsala SE, Sweden
| | - Emilia Lekholm
- Department of Pharmaceutical Bioscience, Molecular Neuropharmacology, Uppsala University, Uppsala SE, Sweden
| | - Vasiliki Arapi
- Department of Pharmaceutical Bioscience, Molecular Neuropharmacology, Uppsala University, Uppsala SE, Sweden
| | - Emelie Perland
- Department of Pharmaceutical Bioscience, Molecular Neuropharmacology, Uppsala University, Uppsala SE, Sweden
| | - Robert Fredriksson
- Department of Pharmaceutical Bioscience, Molecular Neuropharmacology, Uppsala University, Uppsala SE, Sweden
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114
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González A, Hall MN. Nutrient sensing and TOR signaling in yeast and mammals. EMBO J 2017; 36:397-408. [PMID: 28096180 DOI: 10.15252/embj.201696010] [Citation(s) in RCA: 487] [Impact Index Per Article: 69.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 12/12/2016] [Accepted: 12/15/2016] [Indexed: 01/13/2023] Open
Abstract
Coordinating cell growth with nutrient availability is critical for cell survival. The evolutionarily conserved TOR (target of rapamycin) controls cell growth in response to nutrients, in particular amino acids. As a central controller of cell growth, mTOR (mammalian TOR) is implicated in several disorders, including cancer, obesity, and diabetes. Here, we review how nutrient availability is sensed and transduced to TOR in budding yeast and mammals. A better understanding of how nutrient availability is transduced to TOR may allow novel strategies in the treatment for mTOR-related diseases.
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115
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Rodríguez A, Ortega A. Glutamine/Glutamate Transporters in Glial Cells: Much More Than Participants of a Metabolic Shuttle. ADVANCES IN NEUROBIOLOGY 2017; 16:169-183. [PMID: 28828610 DOI: 10.1007/978-3-319-55769-4_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Glial glutamine and glutamate transporters play an important role in glial/neuronal interactions. An excellent model to establish the role of these membrane proteins is the cerebellum. The most abundant glutamatergic synapse in the central nervous system is present in the molecular layer of the cerebellar cortex, and it is entirely wrapped by Bergmann glial cells. The recycling of glutamate involves glutamate and glutamine transporters enriched in these radial glial processes. The functional properties of amino acid glial transporters allow, in an activity-dependent manner, the conformation of protein complexes important for the adequate support of glutamatergic neurotransmission. A detailed description of the most important features of glial glutamate and glutamine transporters follows, and a working model of the molecular mechanisms by which these glutamate and glutamine binding proteins interact, and by these means might modulate cerebellar glutamatergic transactions, is presented.
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Affiliation(s)
- Angelina Rodríguez
- Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro, México
| | - Arturo Ortega
- Departamento de Toxicología, Cinvestav-IPN, Apartado Postal 14-740, México, DF, 07360, México.
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Duan Y, Guo Q, Wen C, Wang W, Li Y, Tan B, Li F, Yin Y. Free Amino Acid Profile and Expression of Genes Implicated in Protein Metabolism in Skeletal Muscle of Growing Pigs Fed Low-Protein Diets Supplemented with Branched-Chain Amino Acids. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:9390-9400. [PMID: 27960294 DOI: 10.1021/acs.jafc.6b03966] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Revealing the expression patterns of genes involved in protein metabolism as affected by diets would be useful for further clarifying the importance of the balance among the branched-chain amino acids (BCAAs), which include leucine (Leu), isoleucine (Ile), and valine (Val). Therefore, we used growing pigs to explore the effects of different dietary BCAA ratios on muscle protein metabolism. The Leu:Ile:Val ratio was 1:0.51:0.63 (20% crude protein, CP), 1:1:1 (17% CP), 1:0.75:0.75 (17% CP), 1:0.51:0.63 (17% CP), and 1:0.25:0.25 (17% CP), respectively. Results showed that compared with the control group, low-protein diets with the BCAA ratio ranging from 1:0.75:0.75 to 1:0.25:0.25 elevated muscle free amino acid (AA) concentrations and AA transporter expression, significantly activated the mammalian target of rapamycin complex 1 pathway, and decreased serum urea nitrogen content and the mRNA expression of genes related to muscle protein degradation (P < 0.05). In conclusion, these results indicated that maintaining the dietary Leu:Ile:Val ratio within 1:0.25:0.25-1:0.75:0.75 in low-protein diets (17% CP) would facilitate the absorption and utilization of free AA and result in improved protein metabolism and muscle growth.
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Affiliation(s)
- Yehui Duan
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences ; Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production; Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Changsha 410125, China
- University of Chinese Academy of Sciences , Beijing 100039, China
| | - Qiuping Guo
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences ; Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production; Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Changsha 410125, China
- University of Chinese Academy of Sciences , Beijing 100039, China
| | - Chaoyue Wen
- Laboratory of Animal Nutrition and Human Health, School of Biology, Hunan Normal University , Changsha, Hunan 410018, China
| | - Wenlong Wang
- Laboratory of Animal Nutrition and Human Health, School of Biology, Hunan Normal University , Changsha, Hunan 410018, China
| | - Yinghui Li
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences ; Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production; Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Changsha 410125, China
- University of Chinese Academy of Sciences , Beijing 100039, China
| | - Bie Tan
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences ; Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production; Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Changsha 410125, China
| | - Fengna Li
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences ; Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production; Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Changsha 410125, China
- Hunan Co-Innovation Center of Animal Production Safety, CICAPS; Hunan Collaborative Innovation Center for Utilization of Botanical Functional Ingredients , Changsha 410128, China
| | - Yulong Yin
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences ; Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production; Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Changsha 410125, China
- Laboratory of Animal Nutrition and Human Health, School of Biology, Hunan Normal University , Changsha, Hunan 410018, China
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Lu HL, Chang CC, Wilson ACC. Amino acid transporters implicated in endocytosis of Buchnera during symbiont transmission in the pea aphid. EvoDevo 2016; 7:24. [PMID: 27895889 PMCID: PMC5117694 DOI: 10.1186/s13227-016-0061-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Accepted: 11/04/2016] [Indexed: 12/29/2022] Open
Abstract
Background Many insects host their obligate, maternally transmitted symbiotic bacteria in specialized cells called bacteriocytes. One of the best-studied insect nutritional endosymbioses is that of the aphid and its endosymbiont, Buchnera aphidicola. Aphids and Buchnera are metabolically and developmentally integrated, but the molecular mechanisms underlying Buchnera transmission and coordination with aphid development remain largely unknown. Previous work using electron microscopy to study aphid asexual embryogenesis has revealed that Buchnera transmission involves exocytosis from a maternal bacteriocyte followed by endocytotic uptake by a blastula. While the importance of exo- and endocytic cellular processes for symbiont transmission is clear, the molecular mechanisms that regulate these processes are not known. Here, we shed light on the molecular mechanisms that regulate Buchnera transmission and developmental integration. Results We present the developmental atlas of ACYPI000536 and ACYPI008904 mRNAs during asexual embryogenesis in the pea aphid, Acyrthosiphon pisum. Immediately before Buchnera invasion, transcripts of both genes were detected by whole-mount in situ hybridization in the posterior syncytial nuclei of late blastula embryos. Following Buchnera invasion, expression of both genes was identified in the region occupied by Buchnera throughout embryogenesis. Notably during Buchnera migration, expression of both genes was not concomitant with the entirety of the bacterial mass but rather expression colocalized with Buchnera in the anterior region of the bacterial mass. In addition, we found that ACYPI000536 was expressed in nuclei at the leading edge of the bacterial mass, joining the bacterial mass in subsequent developmental stages. Finally, quantitative reverse transcription real-time PCR suggested that early in development both transcripts were maternally provisioned to embryos. Conclusions We venture that ACYPI000536 and ACYPI008904 function as nutrient sensors at the site of symbiont invasion to facilitate TOR-pathway-mediated endocytosis of Buchnera by the aphid blastula. Our data support earlier reports of bacteriocyte determination involving a two-step recruitment process but suggest that the second wave of recruitment occurs earlier than previously described. Finally, our work highlights that bacteriocyte-enriched amino acid transporter paralogs have additionally been retained to play novel developmental roles in both symbiont recruitment and bacteriome development. Electronic supplementary material The online version of this article (doi:10.1186/s13227-016-0061-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hsiao-Ling Lu
- Department of Biology, University of Miami, Coral Gables, FL 33146 USA ; Department of Entomology, College of Bioresources and Agriculture, National Taiwan University, Taipei, 10617 Taiwan ; Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei, 10617 Taiwan
| | - Chun-Che Chang
- Department of Entomology, College of Bioresources and Agriculture, National Taiwan University, Taipei, 10617 Taiwan ; Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei, 10617 Taiwan ; Institute of Biotechnology, College of Bioresources and Agriculture, National Taiwan University, Taipei, 10617 Taiwan
| | - Alex C C Wilson
- Department of Biology, University of Miami, Coral Gables, FL 33146 USA
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Qin C, Qiu K, Sun W, Jiao N, Zhang X, Che L, Zhao H, Shen H, Yin J. A proteomic adaptation of small intestinal mucosa in response to dietary protein limitation. Sci Rep 2016; 6:36888. [PMID: 27841298 PMCID: PMC5107940 DOI: 10.1038/srep36888] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 10/21/2016] [Indexed: 12/14/2022] Open
Abstract
Dietary protein limitation (PL) is not only beneficial to human health but also applied to minimize nitrogen excretion in livestock production. However, the impact of PL on intestinal physiology is largely unknown. In this study, we identified 5275 quantitative proteins using a porcine model in which pigs suffered PL. A total of 202 proteins |log2 fold-change| > 1 were taken as differentially expressed proteins and subjected to functional and pathway enrichment analysis to reveal proteomic alterations of the jejunal mucosa. Combining with the results of western blotting analysis, we found that protein/carbohydrate digestion, intestinal mucosal tight junction and cell adhesion molecules, and the immune response to foreign antigens were increased in the jejunal mucosa of the pigs upon PL. In contrast, amino acid transport, innate and auto immunity, as well as cell proliferation and apoptosis were reduced. In addition, the expression of functional proteins that involved in DNA replication, transcription and mRNA splicing as well as translation were altered in the jejunal mucosa in response to PL. Furthermore, PL may reduce amino acid transport and cell proliferation through the depression of mTOR pathway. This study provides new insights into the molecular mechanisms underlying the small intestinal response to PL.
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Affiliation(s)
- Chunfu Qin
- State Key Lab of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, P. R. China
| | - Kai Qiu
- State Key Lab of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, P. R. China
| | - Wenjuan Sun
- State Key Lab of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, P. R. China
| | - Ning Jiao
- State Key Lab of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, P. R. China
| | - Xin Zhang
- State Key Lab of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, P. R. China
| | - Lianqiang Che
- Institute of Animal Nutrition, Sichuan Agricultural University, Ya'an, 625099, P. R. China
| | - Haiyi Zhao
- Genecreate Biological Engineering Co., Ltd., National Bio-industry Base, Wuhan, 430075, P. R. China
| | - Hexiao Shen
- Genecreate Biological Engineering Co., Ltd., National Bio-industry Base, Wuhan, 430075, P. R. China
| | - Jingdong Yin
- State Key Lab of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, P. R. China
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Júnior GAF, Costa RB, de Camargo GMF, Carvalheiro R, Rosa GJM, Baldi F, Garcia DA, Gordo DGM, Espigolan R, Takada L, Magalhães AFB, Bresolin T, Feitosa FLB, Chardulo LAL, de Oliveira HN, de Albuquerque LG. Genome scan for postmortem carcass traits in Nellore cattle1. J Anim Sci 2016; 94:4087-4095. [DOI: 10.2527/jas.2016-0632] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
| | - R. B. Costa
- Faculdade de Ciências Agrárias e Veterinárias, UNESP, Jaboticabal, SP 14884-000, Brazil
| | - G. M. F. de Camargo
- Faculdade de Ciências Agrárias e Veterinárias, UNESP, Jaboticabal, SP 14884-000, Brazil
| | - R. Carvalheiro
- Faculdade de Ciências Agrárias e Veterinárias, UNESP, Jaboticabal, SP 14884-000, Brazil
- CNPq, Brasília, DF, Brazil
| | | | - F. Baldi
- Faculdade de Ciências Agrárias e Veterinárias, UNESP, Jaboticabal, SP 14884-000, Brazil
- CNPq, Brasília, DF, Brazil
| | - D. A. Garcia
- Faculdade de Ciências Agrárias e Veterinárias, UNESP, Jaboticabal, SP 14884-000, Brazil
| | - D. G. M. Gordo
- Faculdade de Ciências Agrárias e Veterinárias, UNESP, Jaboticabal, SP 14884-000, Brazil
| | - R. Espigolan
- Faculdade de Ciências Agrárias e Veterinárias, UNESP, Jaboticabal, SP 14884-000, Brazil
| | - L. Takada
- Faculdade de Ciências Agrárias e Veterinárias, UNESP, Jaboticabal, SP 14884-000, Brazil
| | - A. F. B. Magalhães
- Faculdade de Ciências Agrárias e Veterinárias, UNESP, Jaboticabal, SP 14884-000, Brazil
| | - T. Bresolin
- Faculdade de Ciências Agrárias e Veterinárias, UNESP, Jaboticabal, SP 14884-000, Brazil
| | - F. L. B. Feitosa
- Faculdade de Ciências Agrárias e Veterinárias, UNESP, Jaboticabal, SP 14884-000, Brazil
| | - L. A. L. Chardulo
- Faculdade de Medicina Veterinária e Zootecnia, UNESP, Botucatu, SP 18618-970, Brazil
- CNPq, Brasília, DF, Brazil
| | - H. N. de Oliveira
- Faculdade de Ciências Agrárias e Veterinárias, UNESP, Jaboticabal, SP 14884-000, Brazil
- CNPq, Brasília, DF, Brazil
| | - L. G. de Albuquerque
- Faculdade de Ciências Agrárias e Veterinárias, UNESP, Jaboticabal, SP 14884-000, Brazil
- CNPq, Brasília, DF, Brazil
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Recent Advances in Understanding Amino Acid Sensing Mechanisms that Regulate mTORC1. Int J Mol Sci 2016; 17:ijms17101636. [PMID: 27690010 PMCID: PMC5085669 DOI: 10.3390/ijms17101636] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 09/19/2016] [Accepted: 09/21/2016] [Indexed: 11/25/2022] Open
Abstract
The mammalian target of rapamycin (mTOR) is the central regulator of mammalian cell growth, and is essential for the formation of two structurally and functionally distinct complexes: mTORC1 and mTORC2. mTORC1 can sense multiple cues such as nutrients, energy status, growth factors and hormones to control cell growth and proliferation, angiogenesis, autophagy, and metabolism. As one of the key environmental stimuli, amino acids (AAs), especially leucine, glutamine and arginine, play a crucial role in mTORC1 activation, but where and how AAs are sensed and signal to mTORC1 are not fully understood. Classically, AAs activate mTORC1 by Rag GTPases which recruit mTORC1 to lysosomes, where AA signaling initiates. Plasma membrane transceptor L amino acid transporter 1 (LAT1)-4F2hc has dual transporter-receptor function that can sense extracellular AA availability upstream of mTORC1. The lysosomal AA sensors (PAT1 and SLC38A9) and cytoplasmic AA sensors (LRS, Sestrin2 and CASTOR1) also participate in regulating mTORC1 activation. Importantly, AAs can be sensed by plasma membrane receptors, like G protein-coupled receptor (GPCR) T1R1/T1R3, and regulate mTORC1 without being transported into the cells. Furthermore, AA-dependent mTORC1 activation also initiates within Golgi, which is regulated by Golgi-localized AA transporter PAT4. This review provides an overview of the research progress of the AA sensing mechanisms that regulate mTORC1 activity.
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The mTORC1-Signaling Pathway and Hepatic Polyribosome Profile Are Enhanced after the Recovery of a Protein Restricted Diet by a Combination of Soy or Black Bean with Corn Protein. Nutrients 2016; 8:nu8090573. [PMID: 27657118 PMCID: PMC5037558 DOI: 10.3390/nu8090573] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 08/19/2016] [Accepted: 09/12/2016] [Indexed: 12/13/2022] Open
Abstract
Between 6% and 11% of the world’s population suffers from malnutrition or undernutrition associated with poverty, aging or long-term hospitalization. The present work examined the effect of different types of proteins on the mechanistic target of rapamycin (mTORC1)-signaling pathway in: (1) healthy; and (2) protein restricted rats. (1) In total, 200 rats were divided into eight groups and fed one of the following diets: 20% casein (C), soy (S), black bean (B), B + Corn (BCr), Pea (P), spirulina (Sp), sesame (Se) or Corn (Cr). Rats fed C or BCr had the highest body weight gain; rats fed BCr had the highest pS6K1/S6K1 ratio; rats fed B, BCr or P had the highest eIF4G expression; (2) In total, 84 rats were fed 0.5% C for 21 day and protein rehabilitated with different proteins. The S, soy + Corn (SCr) and BCr groups had the highest body weight gain. Rats fed SCr and BCr had the highest eIF4G expression and liver polysome formation. These findings suggest that the quality of the dietary proteins modulate the mTORC1-signaling pathway. In conclusion, the combination of BCr or SCr are the best proteins for dietary protein rehabilitation due to the significant increase in body weight, activation of the mTORC1-signaling pathway in liver and muscle, and liver polysome formation.
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Protein Restriction with Amino Acid-Balanced Diets Shrinks Circulating Pool Size of Amino Acid by Decreasing Expression of Specific Transporters in the Small Intestine. PLoS One 2016; 11:e0162475. [PMID: 27611307 PMCID: PMC5017764 DOI: 10.1371/journal.pone.0162475] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 08/23/2016] [Indexed: 01/10/2023] Open
Abstract
Dietary protein restriction is not only beneficial to health and longevity in humans, but also protects against air pollution and minimizes feeding cost in livestock production. However, its impact on amino acid (AA) absorption and metabolism is not quite understood. Therefore, the study aimed to explore the effect of protein restriction on nitrogen balance, circulating AA pool size, and AA absorption using a pig model. In Exp.1, 72 gilts weighting 29.9 ± 1.5 kg were allocated to 1 of the 3 diets containing 14, 16, or 18% CP for a 28-d trial. Growth (n = 24), nitrogen balance (n = 6), and the expression of small intestinal AA and peptide transporters (n = 6) were evaluated. In Exp.2, 12 barrows weighting 22.7 ± 1.3 kg were surgically fitted with catheters in the portal and jejunal veins as well as the carotid artery and assigned to a diet containing 14 or 18% CP. A series of blood samples were collected before and after feeding for determining the pool size of circulating AA and AA absorption in the portal vein, respectively. Protein restriction did not sacrifice body weight gain and protein retention, since nitrogen digestibility was increased as dietary protein content reduced. However, the pool size of circulating AA except for lysine and threonine, and most AA flux through the portal vein were reduced in pigs fed the low protein diet. Meanwhile, the expression of peptide transporter 1 (PepT-1) was stimulated, but the expression of the neutral and cationic AA transporter systems was depressed. These results evidenced that protein restriction with essential AA-balanced diets, decreased AA absorption and reduced circulating AA pool size. Increased expression of small intestinal peptide transporter PepT-1 could not compensate for the depressed expression of jejunal AA transporters for AA absorption.
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123
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Semba RD, Trehan I, Gonzalez-Freire M, Kraemer K, Moaddel R, Ordiz MI, Ferrucci L, Manary MJ. Perspective: The Potential Role of Essential Amino Acids and the Mechanistic Target of Rapamycin Complex 1 (mTORC1) Pathway in the Pathogenesis of Child Stunting. Adv Nutr 2016; 7:853-65. [PMID: 27633102 PMCID: PMC5015042 DOI: 10.3945/an.116.013276] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Stunting is the best summary measure of chronic malnutrition in children. Approximately one-quarter of children under age 5 worldwide are stunted. Lipid-based or micronutrient supplementation has little to no impact in reducing stunting, which suggests that other critical dietary nutrients are missing. A dietary pattern of poor-quality protein is associated with stunting. Stunted children have significantly lower circulating essential amino acids than do nonstunted children. Inadequate dietary intakes of essential amino acids could adversely affect growth, because amino acids are required for synthesis of proteins. The master growth regulation pathway, the mechanistic target of rapamycin complex 1 (mTORC1) pathway, is exquisitely sensitive to amino acid availability. mTORC1 integrates cues such as nutrients, growth factors, oxygen, and energy to regulate growth of bone, skeletal muscle, nervous system, gastrointestinal tract, hematopoietic cells, immune effector cells, organ size, and whole-body energy balance. mTORC1 represses protein and lipid synthesis and cell and organismal growth when amino acids are deficient. Over the past 4 decades, the main paradigm for child nutrition in developing countries has been micronutrient malnutrition, with relatively less attention paid to protein. In this Perspective, we present the view that essential amino acids and the mTORC1 pathway play a key role in child growth. The current assumption that total dietary protein intake is adequate for growth among most children in developing countries needs re-evaluation.
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Affiliation(s)
- Richard D Semba
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD;
| | - Indi Trehan
- Department of Pediatrics, Washington University in St. Louis, St. Louis, MO
| | | | - Klaus Kraemer
- Sight and Life, Basel, Switzerland; and Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | | | - M Isabel Ordiz
- Department of Pediatrics, Washington University in St. Louis, St. Louis, MO
| | | | - Mark J Manary
- Department of Pediatrics, Washington University in St. Louis, St. Louis, MO
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Zhang S, Saremi B, Gilbert ER, Wong EA. Physiological and biochemical aspects of methionine isomers and a methionine analogue in broilers. Poult Sci 2016; 96:425-439. [PMID: 27578876 DOI: 10.3382/ps/pew253] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 12/16/2015] [Accepted: 06/28/2016] [Indexed: 12/13/2022] Open
Abstract
Methionine is the first limiting amino acid in all poultry corn-soybean based diets. The objective of this study was to determine the effect of supplementation of L-methionine (L-Met), DL-methionine (DL-Met), and the methionine analogue, DL-2-hydroxy-4-(methylthio) butanoic acid (DL-HMTBA), on biochemical and physiological parameters of broiler chickens. Male Cobb-500 broilers were fed from day of hatch (d 0) to d 35 posthatch using a basal diet deficient in methionine plus cysteine (Met + Cys) (control), or the basal diet supplemented with 0.22% DL-Met, 0.22% L-Met, or 0.31% DL-HMTBA to meet the Met + Cys requirements. Tissue (liver, duodenum, jejunum, and ileum) and blood samples were collected at various ages, from d 0 to d 35. Performance of the birds, blood parameters (e.g., acute phase proteins, white blood cell counts), mRNA expression of intestinal nutrient transporters and DNA methylation properties of liver tissues were examined. Both body weight and feed efficiency were improved in methionine supplemented groups compared to the control group. No significant differences were observed among DL-Met, L-Met, and DL-HMTBA for growth performance parameters. L-Met and DL-Met supplementation decreased the acute phase protein, serum amyloid A, while DL-HMTBA had no effect. Methionine supplementation had no effect on white blood cell differentiation count, hepatic total DNA methylation, or DNA methyltransferase activity. L-Met and DL-Met, but not DL-HMTBA, supplementation, resulted in enhanced expression of the ATB0,+ and B0AT transporters in various small intestinal segments. All methionine sources increased expression of MCT1 in the jejunum. In conclusion, methionine supplementation improved growth performance of male broilers. Methionine supplementation was also associated with changes in intestinal nutrient transporter gene expression in certain segments and ages, suggesting that intestinal amino acid absorptive function can be regulated by the source of amino acid and effects are complex and dynamic.
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Affiliation(s)
- Shuai Zhang
- Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA 24061
| | | | - Elizabeth R Gilbert
- Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA 24061
| | - Eric A Wong
- Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA 24061
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Ro J, Pak G, Malec PA, Lyu Y, Allison DB, Kennedy RT, Pletcher SD. Serotonin signaling mediates protein valuation and aging. eLife 2016; 5. [PMID: 27572262 PMCID: PMC5005037 DOI: 10.7554/elife.16843] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/20/2016] [Indexed: 01/15/2023] Open
Abstract
Research into how protein restriction improves organismal health and lengthens lifespan has largely focused on cell-autonomous processes. In certain instances, however, nutrient effects on lifespan are independent of consumption, leading us to test the hypothesis that central, cell non-autonomous processes are important protein restriction regulators. We characterized a transient feeding preference for dietary protein after modest starvation in the fruit fly, Drosophila melanogaster, and identified tryptophan hydroxylase (Trh), serotonin receptor 2a (5HT2a), and the solute carrier 7-family amino acid transporter, JhI-21, as required for this preference through their role in establishing protein value. Disruption of any one of these genes increased lifespan up to 90% independent of food intake suggesting the perceived value of dietary protein is a critical determinant of its effect on lifespan. Evolutionarily conserved neuromodulatory systems that define neural states of nutrient demand and reward are therefore sufficient to control aging and physiology independent of food consumption. DOI:http://dx.doi.org/10.7554/eLife.16843.001 Limiting the amount of protein eaten, while still eating enough to avoid starving, has an unexpected effect: it can slow down aging and extend the lifespan in many animals from flies to mice. Previous work suggests that how an animal perceives food can also influence how fast the animal ages. For example, both flies and worms actually have shorter lifespans if their food intake is reduced when they can still “smell” food in their environment. However, the sensory cues that trigger changes in lifespan and the molecular mechanisms behind these effects are largely unknown. Ro et al. therefore asked whether fruit flies recognize protein in their food, and if so, whether such a recognition system would influence how the flies age. Flies that had been deprived of food for a brief period tended to eat more protein than other flies that had not been starved. Ro et al. then revealed that serotonin, a brain chemical that can alter the activity of nerve cells, plays a key role in how fruit flies decide to feed specifically on foods that contain protein. Further experiments revealed also that flies age faster when they are allowed to interact with protein in their diet independently from other nutrients, despite eating the same amount. Disrupting any of several components involved in serotonin signaling protected the flies from this effect and led to them living almost twice as long under these conditions. Ro et al. propose that the components of the recognition system work together to determine the reward associated with consuming protein by enhancing how much an animal values the protein in its food. As such, it is this protein reward or value – rather than just eating protein itself – that influences how quickly the fly ages. Further work is now needed to understand how the brain mechanisms that allow animals to perceive and evaluate food act to control lifespan and aging. DOI:http://dx.doi.org/10.7554/eLife.16843.002
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Affiliation(s)
- Jennifer Ro
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, United States
| | - Gloria Pak
- College of Arts and Science, University of Michigan, Ann Arbor, United States
| | - Paige A Malec
- Department of Chemistry, University of Michigan, Ann Arbor, United States
| | - Yang Lyu
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, United States.,Geriatrics Center, University of Michigan, Ann Arbor, United States
| | - David B Allison
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, United States
| | - Robert T Kennedy
- Department of Chemistry, University of Michigan, Ann Arbor, United States
| | - Scott D Pletcher
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, United States.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, United States.,Geriatrics Center, University of Michigan, Ann Arbor, United States
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126
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Cibrián Vera D, Saiz ML, de la Fuente H, Sánchez-Díaz R, Moreno-Gonzalo O, Jorge Cerrudo I, Ferrarini A, Vázquez J, Punzón C, Fresno M, Vicente-Manzanares M, Daudén Tello E, Fernández-Salguero PM, Martín P, Sánchez-Madrid F. CD69 controls the uptake of L-tryptophan through LAT1-CD98 and AhR-dependent secretion of IL-22 in psoriasis. Nat Immunol 2016; 17:985-96. [PMID: 27376471 PMCID: PMC5146640 DOI: 10.1038/ni.3504] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 06/01/2016] [Indexed: 12/13/2022]
Abstract
The activation marker CD69 is expressed by skin γδ T cells. Here we found that CD69 controlled the aryl hydrocarbon receptor (AhR)-dependent secretion of interleukin 22 (IL-22) by γδ T cells, which contributed to the development of psoriasis induced by IL-23. CD69 associated with the aromatic-amino-acid-transporter complex LAT1-CD98 and regulated its surface expression and uptake of L-tryptophan (L-Trp) and the intracellular quantity of L-Trp-derived activators of AhR. In vivo administration of L-Trp, an inhibitor of AhR or IL-22 abrogated the differences between CD69-deficient mice and wild-type mice in skin inflammation. We also observed LAT1-mediated regulation of AhR activation and IL-22 secretion in circulating Vγ9(+) γδ T cells of psoriatic patients. Thus, CD69 serves as a key mediator of the pathogenesis of psoriasis by controlling LAT1-CD98-mediated metabolic cues.
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MESH Headings
- Amino Acid Transport System y+/metabolism
- Amino Acid Transport System y+L
- Animals
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Antigens, Differentiation, T-Lymphocyte/genetics
- Antigens, Differentiation, T-Lymphocyte/metabolism
- Cells, Cultured
- Endocytosis
- Fusion Regulatory Protein-1/metabolism
- Interleukin-23/immunology
- Interleukins/metabolism
- Lectins, C-Type/genetics
- Lectins, C-Type/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Psoriasis/immunology
- Receptors, Antigen, T-Cell, gamma-delta/metabolism
- Receptors, Aryl Hydrocarbon/metabolism
- Skin/immunology
- T-Lymphocyte Subsets/immunology
- Th17 Cells/immunology
- Tryptophan/metabolism
- Interleukin-22
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Affiliation(s)
- Danay Cibrián Vera
- Immunology Service, Hospital de la Princesa, Universidad Autónoma de Madrid, Instituto Investigación Sanitaria Princesa, Madrid, Spain
| | - María Laura Saiz
- Immunology Service, Hospital de la Princesa, Universidad Autónoma de Madrid, Instituto Investigación Sanitaria Princesa, Madrid, Spain
| | - Hortensia de la Fuente
- Immunology Service, Hospital de la Princesa, Universidad Autónoma de Madrid, Instituto Investigación Sanitaria Princesa, Madrid, Spain
| | - Raquel Sánchez-Díaz
- Department of Vascular Biology and Inflammation, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Olga Moreno-Gonzalo
- Immunology Service, Hospital de la Princesa, Universidad Autónoma de Madrid, Instituto Investigación Sanitaria Princesa, Madrid, Spain
| | - Inmaculada Jorge Cerrudo
- Department of Vascular Biology and Inflammation, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Alessia Ferrarini
- Department of Vascular Biology and Inflammation, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Jesús Vázquez
- Department of Vascular Biology and Inflammation, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Carmen Punzón
- Department of Molecular Biology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Manuel Fresno
- Department of Molecular Biology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Miguel Vicente-Manzanares
- Immunology Service, Hospital de la Princesa, Universidad Autónoma de Madrid, Instituto Investigación Sanitaria Princesa, Madrid, Spain
| | | | - Pedro M. Fernández-Salguero
- Department of Biochemistry, Molecular Biology and Genetic, Faculty of Sciences, University of Extremadura, Badajoz, Spain
| | - Pilar Martín
- Department of Vascular Biology and Inflammation, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Francisco Sánchez-Madrid
- Immunology Service, Hospital de la Princesa, Universidad Autónoma de Madrid, Instituto Investigación Sanitaria Princesa, Madrid, Spain
- Department of Vascular Biology and Inflammation, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
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127
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Castro J, Arriola Apelo S, Appuhamy J, Hanigan M. Development of a model describing regulation of casein synthesis by the mammalian target of rapamycin (mTOR) signaling pathway in response to insulin, amino acids, and acetate. J Dairy Sci 2016; 99:6714-6736. [DOI: 10.3168/jds.2015-10591] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 04/19/2016] [Indexed: 11/19/2022]
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128
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Roles of the interorgan neuronal network in the development of metabolic syndrome. Diabetol Int 2016; 7:205-211. [PMID: 30603265 DOI: 10.1007/s13340-016-0277-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 06/26/2016] [Indexed: 01/01/2023]
Abstract
Metabolic processes in different tissues and remote organs are under coordinated systemic regulation, allowing adaptation to a variety of external circumstances. Neuronal signals as well as humoral factors, such as nutrients, growth factors, and hormones, have attracted increasing attention for their roles in this interorgan metabolic network, responsible for the maintenance of metabolic homeostasis at the whole-body level. These interorgan communications within an organism are considered to be diverse and, in fact, we identified previously unknown neuronal relay systems originating in the liver which modulate energy, glucose, and lipid metabolism. Furthermore, when nutrient overload is prolonged, these neuronal mechanisms, which function as an endogenous defense system against obesity development, contribute to the pathophysiological states of metabolic syndrome characterized by obesity-associated features. Therefore, these interorgan neuronal systems are considered to be possible molecular targets for treating metabolic syndrome. We herein review the precise mechanisms underlying the functions of the mammalian interorgan neuronal network, especially the pathways from the liver to several other organs, focusing on their significance and roles in the development of metabolic syndrome.
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129
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Roshanbin S, Lindberg FA, Lekholm E, Eriksson MM, Perland E, Åhlund J, Raine A, Fredriksson R. Histological characterization of orphan transporter MCT14 (SLC16A14) shows abundant expression in mouse CNS and kidney. BMC Neurosci 2016; 17:43. [PMID: 27364523 PMCID: PMC4929735 DOI: 10.1186/s12868-016-0274-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 06/15/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND MCT14 (SLC16A14) is an orphan member of the monocarboxylate transporter (MCT) family, also known as the SLC16 family of secondary active transmembrane transporters. Available expression data for this transporter is limited, and in this paper we aim to characterize MCT14 with respect to tissue distribution and cellular localization in mouse brain. RESULTS Using qPCR, we found that Slc16a14 mRNA was highly abundant in mouse kidney and moderately in central nervous system, testis, uterus and liver. Using immunohistochemistry and in situ hybridization, we determined that MCT14 was highly expressed in excitatory and inhibitory neurons as well as epithelial cells in the mouse brain. The expression was exclusively localized to the soma of neurons. Furthermore, we showed with our phylogenetic analysis that MCT14 most closely relate to the aromatic amino acid- and thyroid-hormone transporters MCT8 (SLC16A2) and MCT10 (SLC16A10), in addition to the carnitine transporter MCT9 (SLC16A9). CONCLUSIONS We provide here the first histological mapping of MCT14 in the brain and our data are consistent with the hypothesis that MCT14 is a neuronal aromatic-amino-acid transporter.
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Affiliation(s)
- Sahar Roshanbin
- Department of Neuroscience, Functional Pharmacology, Uppsala University, 75124, Uppsala, Sweden
| | - Frida A Lindberg
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, 75124, Uppsala, Sweden
| | - Emilia Lekholm
- Department of Neuroscience, Functional Pharmacology, Uppsala University, 75124, Uppsala, Sweden
| | - Mikaela M Eriksson
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, 75124, Uppsala, Sweden
| | - Emelie Perland
- Department of Neuroscience, Functional Pharmacology, Uppsala University, 75124, Uppsala, Sweden
| | - Johan Åhlund
- Department of Neuroscience, Functional Pharmacology, Uppsala University, 75124, Uppsala, Sweden
| | - Amanda Raine
- Department of Neuroscience, Functional Pharmacology, Uppsala University, 75124, Uppsala, Sweden
| | - Robert Fredriksson
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, 75124, Uppsala, Sweden.
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130
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Chen C, Wang J, Cai R, Yuan Y, Guo Z, Grewer C, Zhang Z. Identification of a Disulfide Bridge in Sodium-Coupled Neutral Amino Acid Transporter 2(SNAT2) by Chemical Modification. PLoS One 2016; 11:e0158319. [PMID: 27355203 PMCID: PMC4927162 DOI: 10.1371/journal.pone.0158319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 06/14/2016] [Indexed: 12/02/2022] Open
Abstract
Sodium-coupled neutral amino acid transporter 2 (SNAT2) belongs to solute carrier 38 (SLC38) family of transporters, which is ubiquitously expressed in mammalian tissues and mediates transport of small, neutral amino acids, exemplified by alanine(Ala, A). Yet structural data on SNAT2, including the relevance of intrinsic cysteine residues on structure and function, is scarce, in spite of its essential roles in many tissues. To better define the potential of intrinsic cysteines to form disulfide bonds in SNAT2, mutagenesis experiments and thiol-specific chemical modifications by N-ethylmaleimide (NEM) and methoxy-polyethylene glycol maleimide (mPEG-Mal, MW 5000) were performed, with or without the reducing regent dithiothreitol (DTT) treatment. Seven single mutant transporters with various cysteine (Cys, C) to alanine (Ala, A) substitutions, and a C245,279A double mutant were introduced to SNAT2 with a hemagglutinin (HA) tag at the C-terminus. The results showed that the cells expressing C245A or C279A were labeled by one equivalent of mPEG-Mal in the presence of DTT, while wild-type or all the other single Cys to Ala mutants were modified by two equivalents of mPEG-Mal. Furthermore, the molecular weight of C245,279A was not changed in the presence or absence of DTT treatment. The results suggest a disulfide bond between Cys245 and Cys279 in SNAT2 which has no effect on cell surface trafficking, as well as transporter function. The proposed disulfide bond may be important to delineate proximity in the extracellular domain of SNAT2 and related proteins.
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Affiliation(s)
- Chen Chen
- College of Life Science and Biopharmacy, Shenyang Pharmaceutical University, Shenyang 110015, People’s Republic of China
| | - Jiahong Wang
- College of Life Science and Biopharmacy, Shenyang Pharmaceutical University, Shenyang 110015, People’s Republic of China
| | - Ruiping Cai
- College of Life Science and Biopharmacy, Shenyang Pharmaceutical University, Shenyang 110015, People’s Republic of China
| | - Yanmeng Yuan
- College of Life Science and Biopharmacy, Shenyang Pharmaceutical University, Shenyang 110015, People’s Republic of China
| | - Zhanyun Guo
- Institute of Protein Research, College of Life Sciences and Technology, Tongji University, Shanghai 200092, People’s Republic of China
| | - Christof Grewer
- Departments of Chemistry and Biological Sciences, Binghamton University, Binghamton, New York, 13902, United States of America
| | - Zhou Zhang
- College of Life Science and Biopharmacy, Shenyang Pharmaceutical University, Shenyang 110015, People’s Republic of China
- * E-mail:
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131
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Complementation of Arginine Auxotrophy for Genetic Transformation of Coxiella burnetii by Use of a Defined Axenic Medium. Appl Environ Microbiol 2016; 82:3042-51. [PMID: 26969695 DOI: 10.1128/aem.00261-16] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 03/08/2016] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Host cell-free (axenic) culture of Coxiella burnetii in acidified citrate cysteine medium-2 (ACCM-2) has provided important opportunities for investigating the biology of this naturally obligate intracellular pathogen and enabled the development of tools for genetic manipulation. However, ACCM-2 has complex nutrient sources that preclude a detailed study of nutritional factors required for C. burnetii growth. Metabolic reconstruction of C. burnetii predicts that the bacterium cannot synthesize all amino acids and therefore must sequester some from the host. To examine C. burnetii amino acid auxotrophies, we developed a nutritionally defined medium with known amino acid concentrations, termed ACCM-D. Compared to ACCM-2, ACCM-D supported longer logarithmic growth, a more gradual transition to stationary phase, and approximately 5- to 10-fold greater overall replication. Small-cell-variant morphological forms generated in ACCM-D also showed increased viability relative to that generated in ACCM-2. Lack of growth in amino acid-deficient formulations of ACCM-D revealed C. burnetii auxotrophy for 11 amino acids, including arginine. Heterologous expression of Legionella pneumophila argGH in C. burnetii permitted growth in ACCM-D missing arginine and supplemented with citrulline, thereby providing a nonantibiotic means of selection of C. burnetii genetic transformants. Consistent with bioinformatic predictions, the elimination of glucose did not impair C. burnetii replication. Together, these results highlight the advantages of a nutritionally defined medium in investigations of C. burnetii metabolism and the development of genetic tools. IMPORTANCE Host cell-free growth and genetic manipulation of Coxiella burnetii have revolutionized research of this intracellular bacterial pathogen. Nonetheless, undefined components of growth medium have made studies of C. burnetii physiology difficult and have precluded the development of selectable markers for genetic transformation based on nutritional deficiencies. Here, we describe a medium, containing only amino acids as the sole source of carbon and energy, which supports robust growth and improved viability of C. burnetii Growth studies confirmed that C. burnetii cannot replicate in medium lacking arginine. However, genetic transformation of the bacterium with constructs containing the last two genes in the L. pneumophila arginine biosynthesis pathway (argGH) allowed growth on defined medium missing arginine but supplemented with the arginine precursor citrulline. Our results advance the field by facilitating studies of C. burnetii metabolism and allowing non-antibiotic-based selection of C. burnetii genetic transformants, an important achievement considering that selectable makers based on antibiotic resistance are limited.
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132
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Li YH, Li FN, Wu L, Liu YY, Wei HK, Li TJ, Tan BE, Kong XF, Wu F, Duan YH, Oladele OA, Yin YL. Reduced dietary protein level influences the free amino acid and gene expression profiles of selected amino acid transceptors in skeletal muscle of growing pigs. J Anim Physiol Anim Nutr (Berl) 2016; 101:96-104. [PMID: 27045856 DOI: 10.1111/jpn.12514] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 03/12/2016] [Indexed: 12/22/2022]
Abstract
This study was conducted to evaluate the effect of reduced dietary protein level on growth performance, muscle mass weight, free amino acids (FAA) and gene expression profile of selected amino acid transceptors in different fibre type of skeletal muscle tissues (longissimus dorsi, psoas major, biceps femoris) of growing pigs. A total of 18 cross-bred growing pigs (Large White × Landrace × Duroc) with initial body weight (9.57 ± 0.67 kg) were assigned into three dietary treatments: 20% crude protein (CP) diet (normal recommended, NP), 17% CP diet (low protein, LP) and 14% CP diet (very low protein, VLP). The results indicated improved feed-to-gain ratio was obtained for pigs fed LP and NP diets (p < 0.01), while the pigs fed VLP diet showed the worst growth performance (p < 0.01). There was no significant difference in the weights of longissimus dorsi and psoas major muscle between LP and NP groups (p > 0.05). Majority of the determined FAA concentration of LP group were greater than or equal to those of NP group in both longissimus dorsi and psoas major muscle (p < 0.01). Further, the mRNA expression levels of sodium-coupled neutral amino acid transceptor 2, L-type amino acid transceptor 1 and proton-assisted amino acid transceptors 2 were higher in skeletal muscle tissue in LP group compared to those of the pigs fed NP or VLP diet. These results suggested that reduced dietary protein level (3 points of percentage less than recommended level) would upregulate the mRNA expression of amino acid transceptors to enhance the absorption of FAA in skeletal muscle of growing pigs. There seems to be a relationship between response of AA transceptors to the dietary protein level in skeletal muscle tissue of different fibre type. To illustrate the underlying mechanisms will be beneficial to animal nutrition.
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Affiliation(s)
- Y H Li
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - F N Li
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,Hunan Co-Innovation Center of Animal Production Safety (CICAPS), Changsha, China
| | - L Wu
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
| | - Y Y Liu
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
| | - H K Wei
- College of Animal Sciences, Huazhong Agricultural University, Wuhan, Hubei, China
| | - T J Li
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
| | - B E Tan
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
| | - X F Kong
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
| | - F Wu
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
| | - Y H Duan
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
| | - O A Oladele
- Animal Nutrition Department, College of Animal Science and Livestock Production, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria
| | - Y L Yin
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center of Healthy Livestock, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
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133
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Osorio JS, Lohakare J, Bionaz M. Biosynthesis of milk fat, protein, and lactose: roles of transcriptional and posttranscriptional regulation. Physiol Genomics 2016; 48:231-56. [DOI: 10.1152/physiolgenomics.00016.2015] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The demand for high-quality milk is increasing worldwide. The efficiency of milk synthesis can be improved by taking advantage of the accumulated knowledge of the transcriptional and posttranscriptional regulation of genes coding for proteins involved in the synthesis of fat, protein, and lactose in the mammary gland. Research in this area is relatively new, but data accumulated in the last 10 years provide a relatively clear picture. Milk fat synthesis appears to be regulated, at least in bovines, by an interactive network between SREBP1, PPARγ, and LXRα, with a potential role for other transcription factors, such as Spot14, ChREBP, and Sp1. Milk protein synthesis is highly regulated by insulin, amino acids, and amino acid transporters via transcriptional and posttranscriptional routes, with the insulin-mTOR pathway playing a central role. The transcriptional regulation of lactose synthesis is still poorly understood, but it is clear that glucose transporters play an important role. They can also cooperatively interact with amino acid transporters and the mTOR pathway. Recent data indicate the possibility of nutrigenomic interventions to increase milk fat synthesis by feeding long-chain fatty acids and milk protein synthesis by feeding amino acids. We propose a transcriptional network model to account for all available findings. This model encompasses a complex network of proteins that control milk synthesis with a cross talk between milk fat, protein, and lactose regulation, with mTOR functioning as a central hub.
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Affiliation(s)
| | - Jayant Lohakare
- Oregon State University, Corvallis, Oregon; and
- Kangwon National University, Chuncheon, South Korea
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134
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Hayashi K, Ouchi M, Endou H, Anzai N. HOXB9 acts as a negative regulator of activated human T cells in response to amino acid deficiency. Immunol Cell Biol 2016; 94:612-7. [PMID: 26926958 DOI: 10.1038/icb.2016.13] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 01/22/2016] [Accepted: 01/23/2016] [Indexed: 12/11/2022]
Abstract
T-cell activation is an energy expenditure process and should be properly controlled in accordance with the availability of nutrients such as amino acids to eliminate wasteful energy consumption. However, the details of response to amino acids insufficiency in activated T cells remain largely unknown. Here we show that homeobox B9 (HOXB9), a member of the homeobox gene family that is known as a morphogenesis regulator, acts as a suppressor of activated human T cells to address amino acid starvation. The expression of HOXB9 was triggered by amino acid deprivation as well as functional inhibition of L-type amino acid transporter 1 (also known as SLC7A5) via activating transcription factor 4 in activated T cells. HOXB9 interfered the activities of NF-κB, nuclear factor of activated T-cells (NFAT) and AP-1 but not retinoic acid receptor-related orphan receptor, resulting in attenuation of the production of selective cytokines in activated T cells. Thus, the morphogenetic gene plays an unexpected role in the regulation of cellular metabolism with changes in the nutrition status in human T cells.
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Affiliation(s)
- Keitaro Hayashi
- Department of Pharmacology and Toxicology, Dokkyo Medical University School of Medicine, Tochigi, Japan
| | - Motoshi Ouchi
- Department of Pharmacology and Toxicology, Dokkyo Medical University School of Medicine, Tochigi, Japan
| | | | - Naohiko Anzai
- Department of Pharmacology and Toxicology, Dokkyo Medical University School of Medicine, Tochigi, Japan
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135
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Lu HL, Price DRG, Wikramanayake A, Chang CC, Wilson ACC. Ontogenetic differences in localization of glutamine transporter ApGLNT1 in the pea aphid demonstrate that mechanisms of host/symbiont integration are not similar in the maternal versus embryonic bacteriome. EvoDevo 2016; 7:1. [PMID: 26759710 PMCID: PMC4709974 DOI: 10.1186/s13227-015-0038-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 12/22/2015] [Indexed: 11/17/2022] Open
Abstract
Background Obligate intracellular symbionts of insects are metabolically and developmentally integrated with their hosts. Typically, reproduction fails in many insect nutritional endosymbioses when host insects are cured of their bacterial symbionts, and yet remarkably little is known about the processes that developmentally integrate host and symbiont. Here in the best studied insect obligate intracellular symbiosis, that of the pea aphid, Acyrthosiphon pisum, with the gammaproteobacterium Buchnera aphidicola, we tracked the expression and localization of amino acid transporter ApGLNT1 gene products during asexual embryogenesis. Recently being characterized as a glutamine transporter, ApGLNT1 has been proposed to be a key regulator of amino acid biosynthesis in A. pisum bacteriocytes. To determine when this important mediator of the symbiosis becomes expressed in aphid embryonic bacteriocytes, we applied whole-mount in situ hybridization and fluorescent immunostaining with a specific anti-ApGLNT1 antibody to detect the temporal and spatial expression of ApGLNT1 gene products during asexual embryogenesis. Results During embryogenesis, ApGLNT1 mRNA and protein localize to the follicular epithelium that surrounds parthenogenetic viviparous embryos, where we speculate that it functions to supply developing embryos with glutamine from maternal hemolymph. Unexpectedly, in the embryonic bacteriome ApGLNT1 protein does not localize to the membrane of bacteriocytes, a pattern that leads us to conclude that the regulation of amino acid metabolism in the embryonic bacteriome mechanistically differs from that in the maternal bacteriome. Paralleling our earlier report of punctate cytoplasmic localization of ApGLNT1 in maternal bacteriocytes, we find ApGLNT1 protein localizing as cytoplasmic puncta throughout development in association with Buchnera. Conclusions Our work that documents ontogenetic shifts in the localization of ApGLNT1 protein in the host bacteriome demonstrates that maternal and embryonic bacteriomes are not equivalent. Significantly, the persistent punctate cytoplasmic localization of ApGLNT1 in association with Buchnera in embryos prior to bacteriocyte formation and later in both embryonic and maternal bacteriomes suggests that ApGLNT1 plays multiple roles in this symbiosis, roles that include amino acid transport and possibly nutrient sensing. Electronic supplementary material The online version of this article (doi:10.1186/s13227-015-0038-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hsiao-Ling Lu
- Department of Biology, University of Miami, Coral Gables, FL 33146 USA ; Department of Entomology, College of Bioresources and Agriculture, National Taiwan University, Taipei, Taiwan ; Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei, Taiwan
| | - Daniel R G Price
- Department of Biology, University of Miami, Coral Gables, FL 33146 USA
| | | | - Chun-Che Chang
- Department of Entomology, College of Bioresources and Agriculture, National Taiwan University, Taipei, Taiwan ; Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei, Taiwan
| | - Alex C C Wilson
- Department of Biology, University of Miami, Coral Gables, FL 33146 USA
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136
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Ham DJ, Lynch GS, Koopman R. Amino acid sensing and activation of mechanistic target of rapamycin complex 1: implications for skeletal muscle. Curr Opin Clin Nutr Metab Care 2016; 19:67-73. [PMID: 26560525 DOI: 10.1097/mco.0000000000000240] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE OF REVIEW This article evaluates recent studies on the mechanisms involved in sensing changes in amino acid availability and activation of the mechanistic target of rapamycin complex 1 (mTORC1). RECENT FINDINGS mTORC1 is sensitive to changes in amino acid availability and a well known regulator of protein turnover. The mechanisms of amino acid sensing and mTORC1 signaling are emerging with multiple potential sensors (e.g., solute carrier family 38, member 9, lysosomal protein transmembrane 4 beta/solute carrier family 7, member 5-solute carrier family 3, member 2) and signal transducers (e.g., Sestrins, ADP-ribosylation factor 1, and microspherule protein 1) identified. Studies in various cell lines have unveiled the importance of the lysosome in amino acid sensing and signal transmission. SUMMARY Recent discoveries in amino acid sensing highlight a complex scenario, whereby mTORC1 is not merely sensitive to some amino acids and not others, but where specific amino acids are sensed by specific pathways under specific conditions. The physiological purpose of such an arrangement remains to be unraveled, but it would allow mTORC1 to precisely regulate growth during different metabolic conditions. Understanding the mechanisms responsible for sensing amino acid availability and regulating mTORC1 activity is an important prerequisite for the development of nutritional strategies to combat skeletal muscle wasting disorders.
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Affiliation(s)
- Daniel J Ham
- Basic and Clinical Myology Laboratory, Department of Physiology, The University of Melbourne, Victoria, Australia
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137
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Bhutia YD, Ganapathy V. Glutamine transporters in mammalian cells and their functions in physiology and cancer. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:2531-9. [PMID: 26724577 DOI: 10.1016/j.bbamcr.2015.12.017] [Citation(s) in RCA: 194] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 12/19/2015] [Accepted: 12/22/2015] [Indexed: 01/17/2023]
Abstract
The SLC (solute carrier)-type transporters (~400 in number) in mammalian cells consist of 52 distinct gene families, grouped solely based on the amino acid sequence (primary structure) of the transporter proteins and not on their transport function. Among them are the transporters for amino acids. Fourteen of them, capable of transporting glutamine across the plasma membrane, are found in four families: SLC1, SLC6, SLC7, and SLC38. However, it is generally thought that the members of the SLC38 family are the principal transporters for glutamine. Some of the glutamine transporters are obligatory exchangers whereas some function as active transporters in one direction. While most glutamine transporters mediate the influx of the amino acid into cells, some actually mediate the efflux of the amino acid out of the cells. Glutamine transporters play important roles in a variety of tissues, including the liver, brain, kidney, and placenta, as clearly evident from the biological and biochemical phenotypes resulting from the deletion of specific glutamine transporters in mice. Owing to the obligatory role of glutamine in growth and proliferation of tumor cells, there is increasing attention on glutamine transporters in cancer biology as potential drug targets for cancer treatment. Selective blockers of certain glutamine transporters might be effective in preventing the entry of glutamine and other important amino acids into tumor cells, thus essentially starving these cells to death. This could represent the beginning of a new era in the discovery of novel anticancer drugs with a previously unexplored mode of action. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.
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Affiliation(s)
- Yangzom D Bhutia
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Vadivel Ganapathy
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
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138
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Conditional deletion of CD98hc inhibits osteoclast development. Biochem Biophys Rep 2015; 5:203-210. [PMID: 28955825 PMCID: PMC5600448 DOI: 10.1016/j.bbrep.2015.11.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 10/31/2015] [Accepted: 11/30/2015] [Indexed: 11/22/2022] Open
Abstract
The CD98 heavy chain (CD98hc) regulates virus-induced cell fusion and monocyte fusion, and is involved in amino acid transportation. Here, we examined the role that CD98hc plays in the formation of osteoclasts using CD98hcflox/floxLysM-cre peritoneal macrophages (CD98hc-defect macrophages). Peritoneal macrophages were stimulated with co-cultured with osteoblasts in the presence of 1,25(OH)2 vitamin D3, and thereafter stained with tartrate-resistant acid phosphatase staining solution. The multinucleated osteoclast formation was severely impaired in the peritoneal macrophages isolated from the CD98hc-defect mice compared with those from wild-type mice. CD98hc mediates integrin signaling and amino acid transport through the CD98 light chain (CD98lc). In integrin signaling, suppression of the M-CSF-RANKL-induced phosphorylation of ERK, Akt, JNK and p130Cas were observed at the triggering phase in the CD98h-defect peritoneal macrophages. Moreover, we showed that the general control non-derepressible (GCN) pathway, which was activated by amino acid starvation, was induced by the CD98hc-defect peritoneal macrophages stimulated with RANKL. These results indicate that CD98 plays two important roles in osteoclast formation through integrin signaling and amino acid transport. The osteoclastogenesis was severely impaired in the CD98hc-defect macrophages. CD98hc-defect peritoneal macrophages fall into amino acid starvation, resulting in inducing the general control non-derepressible (GCN) pathway in the osteoclastogenesis.
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139
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Toshima T, Shirabe K, Kurihara T, Itoh S, Harimoto N, Ikegami T, Yoshizumi T, Kawanaka H, Ikeda T, Maehara Y. Profile of plasma amino acids values as a predictor of sepsis in patients following living donor liver transplantation: Special reference to sarcopenia and postoperative early nutrition. Hepatol Res 2015; 45:1170-7. [PMID: 25586674 DOI: 10.1111/hepr.12484] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 01/06/2015] [Accepted: 01/07/2015] [Indexed: 12/13/2022]
Abstract
AIM Sarcopenia is an independent predictor of mortality and sepsis after living donor liver transplantation (LDLT). However, the exact mechanisms by which sarcopenia affects poor prognosis or worse immunity against postoperative sepsis are unclear, particularly regarding muscular amino acid metabolism, and the authors aimed to identify the role of plasma amino acids in sarcopenia by retrospective study. METHODS The area of the psoas muscle in 228 recipients of LDLT was retrospectively measured by dynamic computed tomography. Additionally, plasma amino acid levels were measured both pre- and postoperatively. The impact of plasma amino acids for postoperative sepsis and the relationship between sarcopenia and early nutrition after LDLT were analyzed. RESULTS Among the plasma amino acids, only leucine, isoleucine and glutamine in patients with sarcopenia were significantly lower than those without sarcopenia (each, P < 0.05). Multivariate analysis identified the lower plasma glutamine levels as a risk factor of postoperative sepsis after LDLT (odds ratio 5.371, P = 0.002). In sarcopenia patients, plasma glutamine levels after LDLT were significantly decreased compared with before LDLT in patients both with and without postoperative early nutrition. However, in non-sarcopenia patients with early nutrition, plasma glutamine levels after LDLT were comparable with those before LDLT. CONCLUSION This is the first report to study the profile of plasma amino acid change before and after LDLT. Low preoperative glutamine values were an independent risk factor for predicting postoperative sepsis. The efficacy of postoperative early nutrition may prevent postoperative sepsis by improving glutamine levels.
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Affiliation(s)
- Takeo Toshima
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Ken Shirabe
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takeshi Kurihara
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shinji Itoh
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Norifumi Harimoto
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Toru Ikegami
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tomoharu Yoshizumi
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hirofumi Kawanaka
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tetsuo Ikeda
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yoshihiko Maehara
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Hansen CG, Ng YLD, Lam WLM, Plouffe SW, Guan KL. The Hippo pathway effectors YAP and TAZ promote cell growth by modulating amino acid signaling to mTORC1. Cell Res 2015; 25:1299-313. [PMID: 26611634 DOI: 10.1038/cr.2015.140] [Citation(s) in RCA: 146] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 11/09/2015] [Accepted: 11/10/2015] [Indexed: 02/08/2023] Open
Abstract
YAP and TAZ are transcriptional co-activators and function as the major effectors of the Hippo tumor suppressor pathway, which controls cell growth, tissue homeostasis, and organ size. Here we show that YAP/TAZ play an essential role in amino acid-induced mTORC1 activation, particularly under nutrient-limiting conditions. Mechanistically, YAP/TAZ act via the TEAD transcription factors to induce expression of the high-affinity leucine transporter LAT1, which is a heterodimeric complex of SLC7A5 and SLC3A2. Deletion of YAP/TAZ abolishes expression of LAT1 and reduces leucine uptake. Re-expression of SLC7A5 in YAP/TAZ knockout cells restores leucine uptake and mTORC1 activation. Moreover, SLC7A5 knockout cells phenocopies YAP/TAZ knockout cells which exhibit defective mTORC1 activation in response to amino acids. We further demonstrate that YAP/TAZ act through SLC7A5 to provide cells with a competitive growth advantage. Our study provides molecular insight into the mechanism of YAP/TAZ target genes in cell growth regulation.
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Affiliation(s)
- Carsten Gram Hansen
- Department of Pharmacology and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yuen Lam Dora Ng
- Department of Pharmacology and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Wai-Ling Macrina Lam
- Department of Pharmacology and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Steven W Plouffe
- Department of Pharmacology and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kun-Liang Guan
- Department of Pharmacology and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, USA
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141
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Le Vee M, Jouan E, Lecureur V, Fardel O. Aryl hydrocarbon receptor-dependent up-regulation of the heterodimeric amino acid transporter LAT1 (SLC7A5)/CD98hc (SLC3A2) by diesel exhaust particle extract in human bronchial epithelial cells. Toxicol Appl Pharmacol 2015; 290:74-85. [PMID: 26621329 DOI: 10.1016/j.taap.2015.11.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 11/16/2015] [Accepted: 11/23/2015] [Indexed: 11/25/2022]
Abstract
The heterodimeric L-type amino acid transporter (LAT) 1/CD98hc is overexpressed in lung cancers with a poor prognosis factor. Factors that contribute to LAT1/CD98hc overexpression in lung cells remain however to be determined, but the implication of atmospheric pollution can be suspected. The present study was therefore designed to analyze the effects of diesel exhaust particle (DEP) extract (DEPe) on LAT1/CD98hc expression in bronchial epithelial BEAS-2B cells. Exposure to DEPe up-regulated LAT1 and CD98hc mRNA levels in a concentration-dependent manner, with DEPe EC50 values (around 0.2 μg/mL) relevant to environmental situations. DEPe concomitantly induced LAT1/CD98hc protein expression and LAT1-mediated leucine accumulation in BEAS-2B cells. Inhibition of the aryl hydrocarbon receptor (AhR) pathway through the use of a chemical AhR antagonist or the siRNA-mediated silencing of AhR expression was next found to prevent DEPe-mediated induction of LAT1/CD98hc, indicating that this regulation depends on AhR, known to be activated by major chemical DEP components like polycyclic aromatic hydrocarbons. DEPe exposure was finally shown to induce mRNA expression and activity of matrix metalloproteinase (MMP)-2 in BEAS-2B cells, in a CD98hc/focal adhesion kinase (FAK)/extracellular regulated kinase (ERK) manner, thus suggesting that DEPe-mediated induction of CD98hc triggers activation of the integrin/FAK/ERK signaling pathway known to be involved in MMP-2 regulation. Taken together, these data demonstrate that exposure to DEPe induces functional overexpression of the amino acid transporter LAT1/CD98hc in lung cells. Such a regulation may participate to pulmonary carcinogenic effects of DEPs, owing to the well-documented contribution of LAT1 and CD98hc to cancer development.
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Affiliation(s)
- Marc Le Vee
- Institut de Recherches en Santé, Environnement et Travail (IRSET), UMR INSERM U1085, Faculté de Pharmacie, 2 Avenue du Pr Léon Bernard, 35043 Rennes, France
| | - Elodie Jouan
- Institut de Recherches en Santé, Environnement et Travail (IRSET), UMR INSERM U1085, Faculté de Pharmacie, 2 Avenue du Pr Léon Bernard, 35043 Rennes, France
| | - Valérie Lecureur
- Institut de Recherches en Santé, Environnement et Travail (IRSET), UMR INSERM U1085, Faculté de Pharmacie, 2 Avenue du Pr Léon Bernard, 35043 Rennes, France
| | - Olivier Fardel
- Institut de Recherches en Santé, Environnement et Travail (IRSET), UMR INSERM U1085, Faculté de Pharmacie, 2 Avenue du Pr Léon Bernard, 35043 Rennes, France; Pôle Biologie, Centre Hospitalier Universitaire, 2 rue Henri Le Guilloux, 35033 Rennes, France.
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142
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Anthony TG. Homeostatic responses to amino acid insufficiency. ACTA ACUST UNITED AC 2015; 1:135-137. [PMID: 29767147 PMCID: PMC5945978 DOI: 10.1016/j.aninu.2015.10.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Accepted: 10/16/2015] [Indexed: 12/14/2022]
Abstract
This article provides a brief overview describing how two key signaling pathways, namely the integrated stress response and the mammalian target of rapamycin complex 1, work together to facilitate cellular adaptation to dietary amino acid insufficiency. A deeper understanding of these mechanisms is leading to identification of novel targets which aid in disease treatments, improve stress recovery and increase health span through slowed aging and enhanced metabolic fitness.
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Affiliation(s)
- Tracy G Anthony
- Department of Nutritional Sciences, Rutgers University, New Brunswick 08901, USA
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143
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Uno K, Yamada T, Ishigaki Y, Imai J, Hasegawa Y, Sawada S, Kaneko K, Ono H, Asano T, Oka Y, Katagiri H. A hepatic amino acid/mTOR/S6K-dependent signalling pathway modulates systemic lipid metabolism via neuronal signals. Nat Commun 2015; 6:7940. [PMID: 26268630 PMCID: PMC4557134 DOI: 10.1038/ncomms8940] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 06/30/2015] [Indexed: 12/15/2022] Open
Abstract
Metabolism is coordinated among tissues and organs via neuronal signals. Levels of circulating amino acids (AAs), which are elevated in obesity, activate the intracellular target of rapamycin complex-1 (mTORC1)/S6kinase (S6K) pathway in the liver. Here we demonstrate that hepatic AA/mTORC1/S6K signalling modulates systemic lipid metabolism via a mechanism involving neuronal inter-tissue communication. Hepatic expression of an AA transporter, SNAT2, activates the mTORC1/S6K pathway, and markedly elevates serum triglycerides (TGs), while downregulating adipose lipoprotein lipase (LPL). Hepatic Rheb or active-S6K expression have similar metabolic effects, whereas hepatic expression of dominant-negative-S6K inhibits TG elevation in SNAT2 mice. Denervation, pharmacological deafferentation and β-blocker administration suppress obesity-related hypertriglyceridemia with adipose LPL upregulation, suggesting that signals are transduced between liver and adipose tissue via a neuronal pathway consisting of afferent vagal and efferent sympathetic nerves. Thus, the neuronal mechanism uncovered here serves to coordinate amino acid and lipid levels and contributes to the development of obesity-related hypertriglyceridemia.
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Affiliation(s)
- Kenji Uno
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Tetsuya Yamada
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Yasushi Ishigaki
- Division of Diabetes and Metabolism, Iwate Medical University, Morioka 020-8505, Japan
| | - Junta Imai
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Yutaka Hasegawa
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Shojiro Sawada
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Keizo Kaneko
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Hiraku Ono
- The Fourth Department of Internal Medicine, Saitama Medical University, Saitama 350-0495, Japan
| | - Tomoichiro Asano
- Department of Medical Science, Graduate School of Medicine, University of Hiroshima, Hiroshima 734-8553, Japan
| | - Yoshitomo Oka
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Hideki Katagiri
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan.,Japan Science and Technology Agency, CREST, Sendai 980-8575, Japan
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144
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Napolitano L, Scalise M, Galluccio M, Pochini L, Albanese LM, Indiveri C. LAT1 is the transport competent unit of the LAT1/CD98 heterodimeric amino acid transporter. Int J Biochem Cell Biol 2015; 67:25-33. [PMID: 26256001 DOI: 10.1016/j.biocel.2015.08.004] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 06/10/2015] [Accepted: 08/04/2015] [Indexed: 01/25/2023]
Abstract
LAT1 (SLC7A5) and CD98 (SLC3A2) constitute a heterodimeric transmembrane protein complex that catalyzes amino acid transport. Whether one or both subunits are competent for transport is still unclear. The present work aims to solve this question using different experimental strategies. Firstly, LAT1 and CD98 were immuno-detected in protein extracts from SiHa cells. Under oxidizing conditions, i.e., without addition of SH (thiol) reducing agent DTE, both proteins were revealed as a 120kDa major band. Upon DTE treatment separated bands, corresponding to LAT1(35kDa) or CD98(80kDa), were detected. LAT1 function was evaluated in intact cells as BCH sensitive [(3)H]His transport inhibited by hydrophobic amino acids. Antiport of [(3)H]His was measured in proteoliposomes reconstituted with SiHa cell extract in presence of internal His. Transport was increased by DTE. Hydrophobic amino acids were best inhibitors in addition to hydrophilic Tyr, Gln, Asn and Lys. Cys, Tyr and Gln, included in the intraliposomal space, were transported in antiport with external [(3)H]His. Similar experiments were performed in proteoliposomes reconstituted with the recombinant purified hLAT1. Results overlapping those obtained with native protein were achieved. Lower transport of [(3)H]Leu and [(3)H]Gln with respect to [(3)H]His was detected. Kinetic asymmetry was found with external Km for His lower than internal one. No transport was detected in proteoliposomes reconstituted with recombinant hCD98. The experimental data demonstrate that LAT1 is the sole transport competent subunit of the heterodimer. This conclusion has important outcome for following studies on functional characterization and identification of specific inhibitors with potential application in human therapy.
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Affiliation(s)
- Lara Napolitano
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy
| | - Mariafrancesca Scalise
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy
| | - Michele Galluccio
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy
| | - Lorena Pochini
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy
| | - Leticia Maria Albanese
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy.
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Yang JX, Wang CH, Xu QB, Zhao FQ, Liu JX, Liu HY. Methionyl-Methionine Promotes α-s1 Casein Synthesis in Bovine Mammary Gland Explants by Enhancing Intracellular Substrate Availability and Activating JAK2-STAT5 and mTOR-Mediated Signaling Pathways. J Nutr 2015; 145:1748-53. [PMID: 26108540 DOI: 10.3945/jn.114.208330] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 05/29/2015] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Interest is increasing in the role of peptide-bound amino acids (AAs) in milk protein synthesis because studies have found that the uptake of some essential AAs by the mammary gland cannot meet the requirements for milk protein synthesis. Although the role of dipeptides in milk protein synthesis is clearly established, little is known about the underlying mechanisms. OBJECTIVE The objective of this study was to determine whether small peptides can be taken up intact by the peptide transporters in mammary tissue explants and the underlying mechanisms of the effects of methionyl-methionine (Met-Met) supplementation on milk protein synthesis. METHODS Mammary tissue explants were cultured in conditional medium and then treated with different concentrations of Met-Met that replaced 0%, 5%, 10%, 15%, 20%, and 25% of free Met for another 24 h. In some experiments, explants were cultured with an optimal dose of Met-Met with or without the inhibitors of peptide transporter 2 [PepT2; diethylpyrocarbonate (DEPC), 0.1 mmol/L] and aminopeptidase N (APN; bestatin, 20 μmol/L) for 24 h. RESULTS The substitutions of 15% free Met with Met-Met significantly promoted α-s1 casein (αs1-CN) expression in the mammary explants (P < 0.05). The inhibition of the PepT2 by DEPC or APN by bestatin significantly decreased the Met-Met-stimulated increase of αs1-CN expression (P < 0.05). Compared with the control group (0% Met-Met), absorption of Val, Met, Leu, Phe, Lys, and His was improved, and mRNA abundance of the neutral and basic AA transporter was increased in the 15% Met-Met group (P < 0.05). In addition, the mRNA abundance of the mammalian target of rapamycin (mTOR), p70 ribosomal S6 kinase 1 gene, eukaryotic initiation factor 4E binding protein 1 gene , Janus kinase 2 (JAK2), and signal transducer and activator of transcription 5 (STAT5) was increased in the 15% Met-Met-treated group (P < 0.05). CONCLUSION Met-Met promoted αs1-CN synthesis in cultured bovine mammary gland explants, and this stimulation may be mediated by enhanced intracellular substrate availability and by activating JAK2-STAT5 and mTOR signaling pathways.
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Affiliation(s)
- Jian-Xiang Yang
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, China; and
| | - Cai-Hong Wang
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, China; and
| | - Qing-Biao Xu
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, China; and
| | - Feng-Qi Zhao
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, China; and Laboratory of Lactation and Metabolic Physiology, Department of Animal Science, University of Vermont, Burlington, VT
| | - Jian-Xin Liu
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, China; and
| | - Hong-Yun Liu
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, China; and
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146
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Zhen H, Nakamura K, Kitaura Y, Kadota Y, Ishikawa T, Kondo Y, Xu M, Shimomura Y. Regulation of the plasma amino acid profile by leucine via the system L amino acid transporter. Biosci Biotechnol Biochem 2015; 79:2057-62. [PMID: 26125295 DOI: 10.1080/09168451.2015.1060845] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Plasma concentrations of amino acids reflect the intracellular amino acid pool in mammals. However, the regulatory mechanism requires clarification. In this study, we examined the effect of leucine administration on plasma amino acid profiles in mice with and without the treatment of 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH) or rapamycin as an inhibitor of system L or mammalian target of rapamycin complex 1, respectively. The elevation of plasma leucine concentration after leucine administration was associated with a significant decrease in the plasma concentrations of isoleucine, valine, methionine, phenylalanine, and tyrosine; BCH treatment almost completely blocked the leucine-induced decrease in plasma amino acid concentrations. Rapamycin treatment had much less effects on the actions of leucine than BCH treatment. These results suggest that leucine regulates the plasma concentrations of branched-chain amino acids, methionine, phenylalanine, and tyrosine, and that system L amino acid transporters are involved in the leucine action.
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Affiliation(s)
- Hongmin Zhen
- a Laboratory of Nutritional Biochemistry, Department of Applied Molecular Biosciences , Graduate School of Bioagricultural Sciences, Nagoya University , Nagoya , Japan
| | - Koichi Nakamura
- a Laboratory of Nutritional Biochemistry, Department of Applied Molecular Biosciences , Graduate School of Bioagricultural Sciences, Nagoya University , Nagoya , Japan
| | - Yasuyuki Kitaura
- a Laboratory of Nutritional Biochemistry, Department of Applied Molecular Biosciences , Graduate School of Bioagricultural Sciences, Nagoya University , Nagoya , Japan
| | - Yoshihiro Kadota
- a Laboratory of Nutritional Biochemistry, Department of Applied Molecular Biosciences , Graduate School of Bioagricultural Sciences, Nagoya University , Nagoya , Japan
| | - Takuya Ishikawa
- a Laboratory of Nutritional Biochemistry, Department of Applied Molecular Biosciences , Graduate School of Bioagricultural Sciences, Nagoya University , Nagoya , Japan
| | - Yusuke Kondo
- a Laboratory of Nutritional Biochemistry, Department of Applied Molecular Biosciences , Graduate School of Bioagricultural Sciences, Nagoya University , Nagoya , Japan
| | - Minjun Xu
- a Laboratory of Nutritional Biochemistry, Department of Applied Molecular Biosciences , Graduate School of Bioagricultural Sciences, Nagoya University , Nagoya , Japan
| | - Yoshiharu Shimomura
- a Laboratory of Nutritional Biochemistry, Department of Applied Molecular Biosciences , Graduate School of Bioagricultural Sciences, Nagoya University , Nagoya , Japan
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Robey RB, Weisz J, Kuemmerle NB, Salzberg AC, Berg A, Brown DG, Kubik L, Palorini R, Al-Mulla F, Al-Temaimi R, Colacci A, Mondello C, Raju J, Woodrick J, Scovassi AI, Singh N, Vaccari M, Roy R, Forte S, Memeo L, Salem HK, Amedei A, Hamid RA, Williams GP, Lowe L, Meyer J, Martin FL, Bisson WH, Chiaradonna F, Ryan EP. Metabolic reprogramming and dysregulated metabolism: cause, consequence and/or enabler of environmental carcinogenesis? Carcinogenesis 2015; 36 Suppl 1:S203-31. [PMID: 26106140 PMCID: PMC4565609 DOI: 10.1093/carcin/bgv037] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 02/21/2015] [Accepted: 02/24/2015] [Indexed: 12/20/2022] Open
Abstract
Environmental contributions to cancer development are widely accepted, but only a fraction of all pertinent exposures have probably been identified. Traditional toxicological approaches to the problem have largely focused on the effects of individual agents at singular endpoints. As such, they have incompletely addressed both the pro-carcinogenic contributions of environmentally relevant low-dose chemical mixtures and the fact that exposures can influence multiple cancer-associated endpoints over varying timescales. Of these endpoints, dysregulated metabolism is one of the most common and recognizable features of cancer, but its specific roles in exposure-associated cancer development remain poorly understood. Most studies have focused on discrete aspects of cancer metabolism and have incompletely considered both its dynamic integrated nature and the complex controlling influences of substrate availability, external trophic signals and environmental conditions. Emerging high throughput approaches to environmental risk assessment also do not directly address the metabolic causes or consequences of changes in gene expression. As such, there is a compelling need to establish common or complementary frameworks for further exploration that experimentally and conceptually consider the gestalt of cancer metabolism and its causal relationships to both carcinogenesis and the development of other cancer hallmarks. A literature review to identify environmentally relevant exposures unambiguously linked to both cancer development and dysregulated metabolism suggests major gaps in our understanding of exposure-associated carcinogenesis and metabolic reprogramming. Although limited evidence exists to support primary causal roles for metabolism in carcinogenesis, the universality of altered cancer metabolism underscores its fundamental biological importance, and multiple pleiomorphic, even dichotomous, roles for metabolism in promoting, antagonizing or otherwise enabling the development and selection of cancer are suggested.
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Affiliation(s)
- R Brooks Robey
- Research and Development Service, Veterans Affairs Medical Center, White River Junction, VT 05009, USA, Departments of Medicine and of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, Dartmouth College, Hanover, NH 03756, USA,
| | - Judith Weisz
- Departments of Gynecology and Pathology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Nancy B Kuemmerle
- Research and Development Service, Veterans Affairs Medical Center, White River Junction, VT 05009, USA, Departments of Medicine and of
| | - Anna C Salzberg
- Departments of Gynecology and Pathology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Arthur Berg
- Departments of Gynecology and Pathology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Dustin G Brown
- Department of Environmental and Radiological Health Sciences, Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523, USA
| | - Laura Kubik
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA
| | - Roberta Palorini
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, 20126, Italy, SYSBIO Center for Systems Biology, Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan 20126, Italy
| | - Fahd Al-Mulla
- Department of Pathology, Kuwait University, Safat 13110, Kuwait
| | | | - Annamaria Colacci
- Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna, 40126, Italy
| | - Chiara Mondello
- Institute of Molecular Genetics, National Research Council, Pavia 27100, Italy
| | - Jayadev Raju
- Toxicology Research Division, Bureau of Chemical Safety Food Directorate, Health Products and Food Branch Health Canada, Ottawa, Ontario K1A0K9, Canada
| | - Jordan Woodrick
- Molecular Oncology Program, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, 20057 USA
| | - A Ivana Scovassi
- Institute of Molecular Genetics, National Research Council, Pavia 27100, Italy
| | - Neetu Singh
- Advanced Molecular Science Research Centre, King George's Medical University, Lucknow Uttar Pradesh 226003, India
| | - Monica Vaccari
- Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna, 40126, Italy
| | - Rabindra Roy
- Molecular Oncology Program, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, 20057 USA
| | - Stefano Forte
- Mediterranean Institute of Oncology, Viagrande 95029, Italy
| | - Lorenzo Memeo
- Mediterranean Institute of Oncology, Viagrande 95029, Italy
| | - Hosni K Salem
- Urology Department, kasr Al-Ainy School of Medicine, Cairo University, El Manial, Cairo, 12515, Egypt
| | - Amedeo Amedei
- Department of Experimental and Clinical Medicine, University of Firenze, Firenze, 50134, Italy
| | - Roslida A Hamid
- Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia
| | - Graeme P Williams
- Department of Molecular Medicine, University of Reading, Reading RG6 6UB, UK
| | - Leroy Lowe
- Centre for Biophotonics, LEC, Lancaster University, Bailrigg, Lancaster LA1 4YQ, UK, Getting to Know Cancer, Truro, Nova Scotia B2N 1X5, Canada, and
| | - Joel Meyer
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA
| | - Francis L Martin
- Centre for Biophotonics, LEC, Lancaster University, Bailrigg, Lancaster LA1 4YQ, UK
| | - William H Bisson
- Environmental and Molecular Toxicology, Environmental Health Science Center, Oregon State University, Corvallis, OR 97331, USA
| | - Ferdinando Chiaradonna
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, 20126, Italy, SYSBIO Center for Systems Biology, Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan 20126, Italy
| | - Elizabeth P Ryan
- Department of Environmental and Radiological Health Sciences, Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523, USA
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Schuster AT, Homer CR, Kemp JR, Nickerson KP, Deutschman E, Kim Y, West G, Sadler T, Stylianou E, Krokowski D, Hatzoglou M, de la Motte C, Rubin BP, Fiocchi C, McDonald C, Longworth MS. Chromosome-associated protein D3 promotes bacterial clearance in human intestinal epithelial cells by repressing expression of amino acid transporters. Gastroenterology 2015; 148:1405-1416.e3. [PMID: 25701737 PMCID: PMC4446190 DOI: 10.1053/j.gastro.2015.02.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 01/28/2015] [Accepted: 02/13/2015] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Defects in colonic epithelial barrier defenses are associated with ulcerative colitis (UC). The proteins that regulate bacterial clearance in the colonic epithelium have not been completely identified. The Drosophila chromosome-associated protein D3 (dCAP-D3) regulates responses to bacterial infection. We examined whether CAP-D3 promotes bacterial clearance in human colonic epithelium. METHODS Clearance of Salmonella or adherent-invasive Escherichia coli LF82 was assessed by gentamycin protection assays in HT-29 and Caco-2 cells expressing small hairpin RNAs against CAP-D3. We used immunoblot assays to measure levels of CAP-D3 in colonic epithelial cells from patients with UC and healthy individuals (controls). RNA sequencing identified genes activated by CAP-D3. We analyzed the roles of CAP-D3 target genes in bacterial clearance using gentamycin protection and immunofluorescence assays and studies with pharmacologic inhibitors. RESULTS CAP-D3 expression was reduced in colonic epithelial cells from patients with active UC. Reduced CAP-D3 expression decreased autophagy and impaired intracellular bacterial clearance by HT-29 and Caco-2 colonic epithelial cells. Lower levels of CAP-D3 increased transcription of genes encoding SLC7A5 and SLC3A2, the products of which heterodimerize to form an amino acid transporter in HT-29 cells after bacterial infection; levels of SLC7A5-SLC3A2 were increased in tissues from patients with UC compared with controls. Reduced CAP-D3 in HT-29 cells resulted in earlier recruitment of SLC7A5 to Salmonella-containing vacuoles, increased activity of mTORC1, and increased survival of bacteria. Inhibition of SLC7A5-SLC3A2 or mTORC1 activity rescued the bacterial clearance defects of CAP-D3-deficient cells. CONCLUSIONS CAP-D3 down-regulates transcription of genes that encode amino acid transporters (SLC7A5 and SLC3A2) to promote bacterial autophagy by colon epithelial cells. Levels of CAP-D3 protein are reduced in patients with active UC; strategies to increase its levels might restore mucosal homeostasis to patients with active UC.
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Affiliation(s)
- Andrew T Schuster
- Department of Molecular Genetics, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Craig R Homer
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Jacqueline R Kemp
- Department of Molecular Genetics, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Kourtney P Nickerson
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Emily Deutschman
- Department of Molecular Genetics, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Yeojung Kim
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Gail West
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Tammy Sadler
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Eleni Stylianou
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Dawid Krokowski
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio
| | - Maria Hatzoglou
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio
| | - Carol de la Motte
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Brian P Rubin
- Department of Molecular Genetics, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
- Department of Anatomic Pathology, Taussig Cancer Institute, Cleveland, Ohio
| | - Claudio Fiocchi
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Christine McDonald
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Michelle S Longworth
- Department of Molecular Genetics, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
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149
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Tian J, He G, Mai K, Liu C. Effects of postprandial starvation on mRNA expression of endocrine-, amino acid and peptide transporter-, and metabolic enzyme-related genes in zebrafish (Danio rerio). FISH PHYSIOLOGY AND BIOCHEMISTRY 2015; 41:773-787. [PMID: 25805459 DOI: 10.1007/s10695-015-0045-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 03/18/2015] [Indexed: 06/04/2023]
Abstract
The goal of this study was to systematically evaluate the molecular activities of endocrine-, amino acid and peptide transporters-, and metabolic enzyme-related genes in 35-day-old mixed-sex zebrafish (Danio rerio) after feeding . Zebrafish with initial body weights ranging from 9 to 11 mg were fasted for 384 h in a controlled indoor environment. Fish were sampled at 0, 3, 6, 12, 24, 48, 96, 192, and 384 h after fed. Overall, the present study results show that the regulatory mechanism that insulin-like growth factor I negative feedback regulated growth hormone is conserved in zebrafish, as it is in mammals, but that regulation of growth hormone receptors is highly intricate. Leptin and cholecystokinin are time-dependent negative feedback signals, and neuropeptide Y may be an important positive neuropeptide for food intake in zebrafish. The amino acid/carnitine transporters B(0,+) (ATB(0,+)) and broad neutral (0) amino acid transporter 1(B(0)AT1) mRNA levels measured in our study suggest that protein may be utilized during 24-96 h of fasting in zebrafish. Glutamine synthetase mRNA levels were downregulated, and glutamate dehydrogenase, alanine aminotransferase, aspartate transaminase, and trypsin mRNA levels were upregulated after longtime fasting in this study. The mRNA expression levels of fatty acid synthetase decreased significantly (P < 0.05), whereas those of lipoprotein lipase rapidly increased after 96 h of fasting. Fasting activated the expression of glucose synthesis genes when fasting for short periods of time; when fasting is prolonged, the mRNA levels of glucose breakdown enzymes and pentose phosphate shunt genes decreased.
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Affiliation(s)
- Juan Tian
- Key Laboratory of Aquaculture Nutrition (Ministry of Agriculture), Ocean University of China, No. 5 Yushan Rd., Qingdao, 266003, People's Republic of China,
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150
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Sun Y, Wu Z, Li W, Zhang C, Sun K, Ji Y, Wang B, Jiao N, He B, Wang W, Dai Z, Wu G. Dietary l-leucine supplementation enhances intestinal development in suckling piglets. Amino Acids 2015; 47:1517-25. [DOI: 10.1007/s00726-015-1985-2] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 04/08/2015] [Indexed: 12/14/2022]
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