scholarly journals Evidence for the presence in rainbow trout brain of amino acid-sensing systems involved in the control of food intake

2018 ◽  
Vol 314 (2) ◽  
pp. R201-R215 ◽  
Author(s):  
Sara Comesaña ◽  
Cristina Velasco ◽  
Rosa M. Ceinos ◽  
Marcos A. López-Patiño ◽  
Jesús M. Míguez ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Amino Acid ◽  
Food Intake ◽  
Glutamine Metabolism ◽  
Taste Receptors ◽  
General Control ◽  
Mechanistic Target Of Rapamycin ◽  
Sensing Systems ◽  
Branched Chain ◽  
Amino Acid Sensing

To assess the hypothesis of central amino acid-sensing systems involved in the control of food intake in fish, we carried out two experiments in rainbow trout. In the first one, we injected intracerebroventricularly two different branched-chain amino acids (BCAAs), leucine and valine, and assessed food intake up to 48 h later. Leucine decreased and valine increased food intake. In a second experiment, 6 h after similar intracerebroventricular treatment we determined changes in parameters related to putative amino acid-sensing systems. Different areas of rainbow trout brain present amino acid-sensing systems responding to leucine (hypothalamus and telencephalon) and valine (telencephalon), while other areas (midbrain and hindbrain) do not respond to these treatments. The decreased food intake observed in fish treated intracerebroventricularly with leucine could relate to changes in mRNA abundance of hypothalamic neuropeptides [proopiomelanocortin (POMC), cocaine- and amphetamine-related transcript (CART), neuropeptide Y (NPY), and agouti-related peptide (AgRP)]. These in turn could relate to amino acid-sensing systems present in the same area, related to BCAA and glutamine metabolism, as well as mechanistic target of rapamycin (mTOR), taste receptors, and general control nonderepressible 2 (GCN2) kinase signaling. The treatment with valine did not affect amino acid-sensing parameters in the hypothalamus. These responses are comparable to those characterized in mammals. However, clear differences arise when comparing rainbow trout and mammals, in particular with respect to the clear orexigenic effect of valine, which could relate to the finding that valine partially stimulated two amino acid-sensing systems in the telencephalon. Another novel result is the clear effect of leucine on telencephalon, in which amino acid-sensing systems, but not neuropeptides, were activated as in the hypothalamus.

scholarly journals Impaired branched chain amino acid metabolism alters feeding behavior and increases orexigenic neuropeptide expression in the hypothalamus

2011 ◽  
Vol 212 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Megan N Purpera ◽  
Li Shen ◽  
Marzieh Taghavi ◽  
Heike Münzberg ◽  
Roy J Martin ◽  
...  
Keyword(s):  
Amino Acid ◽  
Food Intake ◽  
Feeding Behavior ◽  
Control Diet ◽  
Peripheral Tissues ◽  
Protein Status ◽  
Branched Chain Amino Acid ◽  
Branched Chain ◽  
Branched Chain Aminotransferase ◽  
Deficient Mice

Elevation of dietary or brain leucine appears to suppress food intake via a mechanism involving mechanistic target of rapamycin, AMPK, and/or branched chain amino acid (BCAA) metabolism. Mice bearing a deletion of mitochondrial branched chain aminotransferase (BCATm), which is expressed in peripheral tissues (muscle) and brain glia, exhibit marked increases in circulating BCAAs. Here, we test whether this increase alters feeding behavior and brain neuropeptide expression. Circulating and brain levels of BCAAs were increased two- to four-fold in BCATm-deficient mice (KO). KO mice weighed less than controls (25.9 vs 20.4 g,P<0.01), but absolute food intake was relatively unchanged. In contrast to wild-type mice, KO mice preferred a low-BCAA diet to a control diet (P<0.05) but exhibited no change in preference for low- vs high-protein (HP) diets. KO mice also exhibited low leptin levels and increased hypothalamicNpyandAgrpmRNA. Normalization of circulating leptin levels had no effect on either food preference or the increasedNpyandAgrpmRNA expression. If BCAAs act as signals of protein status, one would expect reduced food intake, avoidance of dietary protein, and reduction in neuropeptide expression in BCATm-KO mice. Instead, these mice exhibit an increased expression of orexigenic neuropeptides and an avoidance of BCAAs but not HP. These data thus suggest that either BCAAs do not act as physiological signals of protein status or the loss of BCAA metabolism within brain glia impairs the detection of protein balance.

scholarly journals Polarization of M2 macrophages requires Lamtor1 that integrates cytokine and amino-acid signals

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Tetsuya Kimura ◽  
Shigeyuki Nada ◽  
Noriko Takegahara ◽  
Tatsusada Okuno ◽  
Satoshi Nojima ◽  
...  
Keyword(s):  
Amino Acid ◽  
Macrophage Activation ◽  
Adaptor Protein ◽  
M2 Macrophages ◽  
Downstream Target ◽  
Mechanistic Target Of Rapamycin ◽  
M2 Polarization ◽  
M1 Polarization ◽  
Amino Acid Sensing ◽  
M1 And M2 Macrophages

Abstract Macrophages play crucial roles in host defence and tissue homoeostasis, processes in which both environmental stimuli and intracellularly generated metabolites influence activation of macrophages. Activated macrophages are classified into M1 and M2 macrophages. It remains unclear how intracellular nutrition sufficiency, especially for amino acid, influences on macrophage activation. Here we show that a lysosomal adaptor protein Lamtor1, which forms an amino-acid sensing complex with lysosomal vacuolar-type H+-ATPase (v-ATPase), and is the scaffold for amino acid-activated mTORC1 (mechanistic target of rapamycin complex 1), is critically required for M2 polarization. Lamtor1 deficiency, amino-acid starvation, or inhibition of v-ATPase and mTOR result in defective M2 polarization and enhanced M1 polarization. Furthermore, we identified liver X receptor (LXR) as the downstream target of Lamtor1 and mTORC1. Production of 25-hydroxycholesterol is dependent on Lamtor1 and mTORC1. Our findings demonstrate that Lamtor1 plays an essential role in M2 polarization, coupling immunity and metabolism.

Involvement of Food Intake and Amino Acid Catabolism in the Branched-Chain Amino Acid Antagonism in Chicks

1982 ◽  
Vol 112 (4) ◽  
pp. 627-635 ◽  
Author(s):  
C. C. Calvert ◽  
K. C. Klasing ◽  
R. E. Austic
Keyword(s):  
Amino Acid ◽  
Food Intake ◽  
Amino Acid Catabolism ◽  
Branched Chain Amino Acid ◽  
Branched Chain

Dietary Branched-Chain Amino Acids Regulate Food Intake Partly through Intestinal and Hypothalamic Amino Acid Receptors in Piglets

2019 ◽  
Vol 67 (24) ◽  
pp. 6809-6818 ◽  
Author(s):  
Min Tian ◽  
Jinghui Heng ◽  
Hanqing Song ◽  
Kui Shi ◽  
Xiaofeng Lin ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Food Intake ◽  
Branched Chain Amino Acids ◽  
Amino Acid Receptors ◽  
Regulate Food Intake ◽  
Branched Chain

Monomethyl branched-chain fatty acid mediates amino acid sensing upstream of mTORC1

2021 ◽  
Author(s):  
Mengnan Zhu ◽  
Fukang Teng ◽  
Na Li ◽  
Li Zhang ◽  
Shuxian Zhang ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Amino Acid ◽  
Chain Fatty Acid ◽  
Branched Chain ◽  
Amino Acid Sensing

scholarly journals Hypothalamic fatty acid sensing in Senegalese sole (Solea senegalensis): response to long-chain saturated, monounsaturated, and polyunsaturated (n-3) fatty acids

2015 ◽  
Vol 309 (12) ◽  
pp. R1521-R1531 ◽  
Author(s):  
Marta Conde-Sieira ◽  
Kruno Bonacic ◽  
Cristina Velasco ◽  
Luisa M. P. Valente ◽  
Sofia Morais ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Rainbow Trout ◽  
Food Intake ◽  
Chain Length ◽  
Acyl Chain ◽  
Marine Species ◽  
Degree Of Saturation ◽  
Solea Senegalensis ◽  
Senegalese Sole ◽  
Sensing Systems

We assessed the presence of fatty acid (FA)-sensing mechanisms in hypothalamus of Senegalese sole ( Solea senegalensis) and investigated their sensitivity to FA chain length and/or level of unsaturation. Stearate (SA, saturated FA), oleate (OA, monounsaturated FA of the same chain length), α-linolenate [ALA, a n-3 polyunsaturated fatty acid (PUFA) of the same chain length], and eicosapentanoate (EPA, a n-3 PUFA of a larger chain length) were injected intraperitoneally. Parameters related to FA sensing and neuropeptide expression in the hypothalamus were assessed after 3 h and changes in accumulated food intake after 4, 24, and 48 h. Three FA sensing systems characterized in rainbow trout were also found in Senegalese sole and were activated by OA in a way similar to that previously characterized in rainbow trout and mammals. These hypothalamic FA sensing systems were also activated by ALA, differing from mammals, where n-3 PUFAs do not seem to activate FA sensors. This might suggest additional roles and highlights the importance of n-3 PUFA in fish diets, especially in marine species. The activation of FA sensing seems to be partially dependent on acyl chain length and degree of saturation, as no major changes were observed after treating fish with SA or EPA. The activation of FA sensing systems by OA and ALA, but not SA or EPA, is further reflected in the expression of hypothalamic neuropeptides involved in the control of food intake. Both OA and ALA enhanced anorexigenic capacity compatible with the activation of FA sensing systems.

scholarly journals Monomethyl branched-chain fatty acid mediates amino acid sensing by mTORC1

2020 ◽  
Author(s):  
Mengnan Zhu ◽  
Fukang Teng ◽  
Na Li ◽  
Li Zhang ◽  
Jing Shao ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Amino Acid ◽  
Protein Translation ◽  
Postembryonic Development ◽  
Chain Fatty Acid ◽  
Nutrient Sensing ◽  
Acid Deficiency ◽  
Branched Chain ◽  
Amino Acid Sensing ◽  
The Impact

AbstractAnimals have developed various nutrient-sensing mechanisms for survival under fluctuating environments. Although extensive cultured cell-based analyses have discovered diverse mediators of amino acid sensing by mTOR, studies using animal models to illustrate intestine-initiated amino acid sensing mechanisms under specific physiological conditions are lacking. Here we developed a Caenorhabditis elegans model to examine the impact of amino acid deficiency on development. We discovered a leucine-derived monomethyl branched-chain fatty acid, and downstream glycosphingolipid, that critically mediate overall amino acid sensing by intestinal and neuronal mTORC1 that, in turn, regulates postembryonic development partly by controlling protein translation and ribosomal biogenesis. Additional data suggest that a similar mechanism may be conserved in mammals. This study uncovers an unexpected amino acid sensing mechanism mediated by a lipid biosynthesis pathway.

scholarly journals The E3 ubiquitin ligase ZNRF2 is a substrate of mTORC1 and regulates its activation by amino acids

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Gerta Hoxhaj ◽  
Edward Caddye ◽  
Ayaz Najafov ◽  
Vanessa P Houde ◽  
Catherine Johnson ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Ubiquitin Ligase ◽  
Protein Phosphatase ◽  
E3 Ubiquitin Ligase ◽  
Mechanistic Target Of Rapamycin ◽  
Rag Gtpases ◽  
Intracellular Amino Acid ◽  
Amino Acid Levels ◽  
Amino Acid Sensing

The mechanistic Target of Rapamycin complex 1 (mTORC1) senses intracellular amino acid levels through an intricate machinery, which includes the Rag GTPases, Ragulator and vacuolar ATPase (V-ATPase). The membrane-associated E3 ubiquitin ligase ZNRF2 is released into the cytosol upon its phosphorylation by Akt. In this study, we show that ZNRF2 interacts with mTOR on membranes, promoting the amino acid-stimulated translocation of mTORC1 to lysosomes and its activation in human cells. ZNRF2 also interacts with the V-ATPase and preserves lysosomal acidity. Moreover, knockdown of ZNRF2 decreases cell size and cell proliferation. Upon growth factor and amino acid stimulation, mTORC1 phosphorylates ZNRF2 on Ser145, and this phosphosite is dephosphorylated by protein phosphatase 6. Ser145 phosphorylation stimulates vesicle-to-cytosol translocation of ZNRF2 and forms a novel negative feedback on mTORC1. Our findings uncover ZNRF2 as a component of the amino acid sensing machinery that acts upstream of Rag-GTPases and the V-ATPase to activate mTORC1.

scholarly journals Amino acid sensing in hypothalamic tanycytes via umami taste receptors

2017 ◽  
Vol 6 (11) ◽  
pp. 1480-1492 ◽  
Author(s):  
Greta Lazutkaite ◽  
Alice Soldà ◽  
Kristina Lossow ◽  
Wolfgang Meyerhof ◽  
Nicholas Dale
Keyword(s):  
Amino Acid ◽  
Taste Receptors ◽  
Umami Taste ◽  
Amino Acid Sensing
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