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Wessels AG. Influence of the Gut Microbiome on Feed Intake of Farm Animals. Microorganisms 2022; 10:microorganisms10071305. [PMID: 35889024 PMCID: PMC9315566 DOI: 10.3390/microorganisms10071305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/23/2022] [Accepted: 06/25/2022] [Indexed: 12/04/2022] Open
Abstract
With the advancement of microbiome research, the requirement to consider the intestinal microbiome as the “last organ” of an animal emerged. Through the production of metabolites and/or the stimulation of the host’s hormone and neurotransmitter synthesis, the gut microbiota can potentially affect the host’s eating behavior both long and short-term. Based on current evidence, the major mediators appear to be short-chain fatty acids (SCFA), peptide hormones such as peptide YY (PYY) and glucagon-like peptide-1 (GLP-1), as well as the amino acid tryptophan with the associated neurotransmitter serotonin, dopamine and γ-Aminobutyrate (GABA). The influence appears to extend into central neuronal networks and the expression of taste receptors. An interconnection of metabolic processes with mechanisms of taste sensation suggests that the gut microbiota may even influence the sensations of their host. This review provides a summary of the current status of microbiome research in farm animals with respect to general appetite regulation and microbiota-related observations made on the influence on feed intake. This is briefly contrasted with the existing findings from research with rodent models in order to identify future research needs. Increasing our understanding of appetite regulation could improve the management of feed intake, feed frustration and anorexia related to unhealthy conditions in farm animals.
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Affiliation(s)
- Anna Grete Wessels
- Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, 14195 Berlin, Germany
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2
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Cilberti MG, Santillo A, Polito AN, Messina G, della Malva A, Caroprese M, Sevi A, Albenzio M. Cytokine Pattern of Peripheral Blood Mononuclear Cells Isolated from Children Affected by Generalized Epilepsy Treated with Different Protein Fractions of Meat Sources. Nutrients 2022; 14:nu14112243. [PMID: 35684043 PMCID: PMC9182632 DOI: 10.3390/nu14112243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 05/24/2022] [Accepted: 05/25/2022] [Indexed: 02/01/2023] Open
Abstract
The objective of the present study was the evaluation of cytokine patterns in terms of TNF-α, IL-10, IL-6, and IL-1β secretion in peripheral blood mononuclear cell (PBMC) supernatants isolated from blood of children affected by generalized epilepsy and treated in vitro with myofibrillar, sarcoplasmic, and total protein fractions of meat and fish sources. Children with generalized epilepsy (EC group, n = 16) and children without any clinical signs of disease, representing a control group (CC group n = 16), were recruited at the Complex Structure of Neuropsychiatry Childhood-Adolescence of Policlinico Riuniti (Foggia, Italy). Myofibrillar (MYO), sarcoplasmic (SA), and total (TOT) protein fractions were obtained from longissimus thoracis muscle of beef (BF) and lamb (LA); from pectoralis muscle of chicken (CH); and from dorsal white muscle of sole (Solea solea, SO), European hake (Merluccius merluccius, EH), and sea bass fish (Dicentrarchus labrax, SB), respectively. PBMCs were isolated from peripheral blood of EC and CC groups, and an in vitro stimulation in the presence of 100 μg/mL for each protein fraction from different meat sources was performed. Data were classified according to three different levels of cytokines produced from the EC group relative to the CC group. TNF-α, IL-10, and IL-6 levels were not affected by different meat fractions and meat sources; on the contrary, IL-1β levels were found to be significantly affected by the tested proteins fractions, as well as different meat sources, in high-level cytokine group. On average, the protein fractions obtained from LB, BF, and CH meat sources showed a higher level of IL-1β than the protein fractions obtained from EH and SB fish samples. When all cytokine classes were analyzed, on average, a significant effect was observed for IL-10, IL-1β, and TNF-α. Data obtained in the present study evidence that the nutritional strategy based on protein from fish and meat sources may modulate the immunological cytokine pattern of infants with generalized epilepsy.
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Affiliation(s)
- Maria Giovanna Cilberti
- Department of Agriculture, Food, Natural Resources, and Engineering (DAFNE), University of Foggia, 71122 Foggia, Italy; (M.G.C.); (A.d.M.); (M.C.); (A.S.); (M.A.)
| | - Antonella Santillo
- Department of Agriculture, Food, Natural Resources, and Engineering (DAFNE), University of Foggia, 71122 Foggia, Italy; (M.G.C.); (A.d.M.); (M.C.); (A.S.); (M.A.)
- Correspondence:
| | - Anna N. Polito
- Complex Structure of Neuropsychiatry Childhood-Adolescence of Ospedali Riuniti of Foggia, Viale Pinto, 71122 Foggia, Italy;
| | - Giovanni Messina
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy;
| | - Antonella della Malva
- Department of Agriculture, Food, Natural Resources, and Engineering (DAFNE), University of Foggia, 71122 Foggia, Italy; (M.G.C.); (A.d.M.); (M.C.); (A.S.); (M.A.)
| | - Mariangela Caroprese
- Department of Agriculture, Food, Natural Resources, and Engineering (DAFNE), University of Foggia, 71122 Foggia, Italy; (M.G.C.); (A.d.M.); (M.C.); (A.S.); (M.A.)
| | - Agostino Sevi
- Department of Agriculture, Food, Natural Resources, and Engineering (DAFNE), University of Foggia, 71122 Foggia, Italy; (M.G.C.); (A.d.M.); (M.C.); (A.S.); (M.A.)
| | - Marzia Albenzio
- Department of Agriculture, Food, Natural Resources, and Engineering (DAFNE), University of Foggia, 71122 Foggia, Italy; (M.G.C.); (A.d.M.); (M.C.); (A.S.); (M.A.)
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3
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Fibroblast Growth Factor 21 Facilitates the Homeostatic Control of Feeding Behavior. J Clin Med 2022; 11:jcm11030580. [PMID: 35160033 PMCID: PMC8836936 DOI: 10.3390/jcm11030580] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 02/01/2023] Open
Abstract
Fibroblast growth factor 21 (FGF21) is a stress hormone that is released from the liver in response to nutritional and metabolic challenges. In addition to its well-described effects on systemic metabolism, a growing body of literature now supports the notion that FGF21 also acts via the central nervous system to control feeding behavior. Here we review the current understanding of FGF21 as a hormone regulating feeding behavior in rodents, non-human primates, and humans. First, we examine the nutritional contexts that induce FGF21 secretion. Initial reports describing FGF21 as a ‘starvation hormone’ have now been further refined. FGF21 is now better understood as an endocrine mediator of the intracellular stress response to various nutritional manipulations, including excess sugars and alcohol, caloric deficits, a ketogenic diet, and amino acid restriction. We discuss FGF21’s effects on energy intake and macronutrient choice, together with our current understanding of the underlying neural mechanisms. We argue that the behavioral effects of FGF21 function primarily to maintain systemic macronutrient homeostasis, and in particular to maintain an adequate supply of protein and amino acids for use by the cells.
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4
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East BS, Fleming G, Vervoordt S, Shah P, Sullivan RM, Wilson DA. Basolateral amygdala to posterior piriform cortex connectivity ensures precision in learned odor threat. Sci Rep 2021; 11:21746. [PMID: 34741138 PMCID: PMC8571329 DOI: 10.1038/s41598-021-01320-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 10/20/2021] [Indexed: 12/24/2022] Open
Abstract
Odor perception can both evoke emotional states and be shaped by emotional or hedonic states. The amygdala complex plays an important role in recognition of, and response to, hedonically valenced stimuli, and has strong, reciprocal connectivity with the primary olfactory (piriform) cortex. Here, we used differential odor-threat conditioning in rats to test the role of basolateral amygdala (BLA) input to the piriform cortex in acquisition and expression of learned olfactory threat responses. Using local field potential recordings, we demonstrated that functional connectivity (high gamma band coherence) between the BLA and posterior piriform cortex (pPCX) is enhanced after differential threat conditioning. Optogenetic suppression of activity within the BLA prevents learned threat acquisition, as do lesions of the pPCX prior to threat conditioning (without inducing anosmia), suggesting that both regions are critical for acquisition of learned odor threat responses. However, optogenetic BLA suppression during testing did not impair threat response to the CS+ , but did induce generalization to the CS-. A similar loss of stimulus control and threat generalization was induced by selective optogenetic suppression of BLA input to pPCX. These results suggest an important role for amygdala-sensory cortical connectivity in shaping responses to threatening stimuli.
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Affiliation(s)
- Brett S East
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA
- Child and Adolescent Psychiatry, New York University Langone Medical Center, 1 Park Avenue, 7th Floor, New York, NY, 10016, USA
| | - Gloria Fleming
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Samantha Vervoordt
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Prachi Shah
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Regina M Sullivan
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA
- Child and Adolescent Psychiatry, New York University Langone Medical Center, 1 Park Avenue, 7th Floor, New York, NY, 10016, USA
| | - Donald A Wilson
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA.
- Child and Adolescent Psychiatry, New York University Langone Medical Center, 1 Park Avenue, 7th Floor, New York, NY, 10016, USA.
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5
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Pezeshki A, Chelikani PK. Low Protein Diets and Energy Balance: Mechanisms of Action on Energy Intake and Expenditure. Front Nutr 2021; 8:655833. [PMID: 34055853 PMCID: PMC8155302 DOI: 10.3389/fnut.2021.655833] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 04/20/2021] [Indexed: 12/30/2022] Open
Abstract
Low protein diets are associated with increased lifespan and improved cardiometabolic health primarily in rodents, and likely improve human health. There is strong evidence that moderate to severe reduction in dietary protein content markedly influences caloric intake and energy expenditure, which is often followed by a decrease in body weight and adiposity in animal models. While the neuroendocrine signals that trigger hyperphagic responses to protein restriction are better understood, there is accumulating evidence that increased sympathetic flux to brown adipose tissue, fibroblast growth factor-21 and serotonergic signaling are important for the thermogenic effects of low protein diets. This mini-review specifically focuses on the effect of low protein diets with variable carbohydrate and lipid content on energy intake and expenditure, and the underlying mechanisms of actions by these diets. Understanding the mechanisms by which protein restriction influences energy balance may unveil novel approaches for treating metabolic disorders in humans and improve production efficiency in domestic animals.
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Affiliation(s)
- Adel Pezeshki
- Department of Animal and Food Sciences, Oklahoma State University, Stillwater, OK, United States
| | - Prasanth K Chelikani
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States.,Department of Nutritional Sciences, College of Human Sciences, Texas Tech University, Lubbock, TX, United States
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6
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Viscosity Measurement Sensor: A Prototype for a Novel Medical Diagnostic Method Based on Quartz Crystal Resonator. SENSORS 2021; 21:s21082743. [PMID: 33924605 PMCID: PMC8070455 DOI: 10.3390/s21082743] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/08/2021] [Accepted: 04/09/2021] [Indexed: 12/26/2022]
Abstract
Viscosity variation in human fluids, such as Synovial Fluid (SF) or Cerebrospinal Fluid (CSF), can be used as a diagnostic factor; however, the sample volume obtained for analysis is usually small, making it difficult to measure its viscosity. On the other hand, Quartz Crystal Resonators (QCR) have been used widely in sensing applications due to their accuracy, cost, and size. This work provides the design and validation of a new viscosity measurement system based on quartz crystal resonators for low volume fluids, leading to the development of a sensor called “ViSQCT” as a prototype for a new medical diagnostic tool. The proposed method is based on measuring the resonance frequency at the crystal’s maximum conductance point through a frequency sweep, where crystals with 10 MHz fundamental resonance frequency were used. For validation purposes, artificial fluids were developed to simulate SFs and CFs in healthy and pathological conditions as experiment phantoms. A commercial QCR based system was also used for validation since its methodology differs from ours. A conventional rotational viscometer was used as a reference for calibration purposes. ViSQCT demonstrates the capability to measure the sample’s viscosity differentiation between healthy and pathological fluid phantoms and shows that it can be used as a basis for a diagnostic method of several pathologies related to the studied biological fluids. However, some performance differences between both QCR-based systems compared to the reference system deserves further investigation.
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7
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Olson B, Marks DL, Grossberg AJ. Diverging metabolic programmes and behaviours during states of starvation, protein malnutrition, and cachexia. J Cachexia Sarcopenia Muscle 2020; 11:1429-1446. [PMID: 32985801 PMCID: PMC7749623 DOI: 10.1002/jcsm.12630] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 09/04/2020] [Accepted: 09/07/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Our evolutionary history is defined, in part, by our ability to survive times of nutrient scarcity. The outcomes of the metabolic and behavioural adaptations during starvation are highly efficient macronutrient allocation, minimization of energy expenditure, and maximized odds of finding food. However, in different contexts, caloric deprivation is met with vastly different physiologic and behavioural responses, which challenge the primacy of energy homeostasis. METHODS We conducted a literature review of scientific studies in humans, laboratory animals, and non-laboratory animals that evaluated the physiologic, metabolic, and behavioural responses to fasting, starvation, protein-deficient or essential amino acid-deficient diets, and cachexia. Studies that investigated the changes in ingestive behaviour, locomotor activity, resting metabolic rate, and tissue catabolism were selected as the focus of discussion. RESULTS Whereas starvation responses prioritize energy balance, both protein malnutrition and cachexia present existential threats that induce unique adaptive programmes, which can exacerbate the caloric insufficiency of undernutrition. We compare and contrast the behavioural and metabolic responses and elucidate the mechanistic pathways that drive state-dependent alterations in energy seeking and partitioning. CONCLUSIONS The evolution of energetically inefficient metabolic and behavioural responses to protein malnutrition and cachexia reveal a hierarchy of metabolic priorities governed by discrete regulatory networks.
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Affiliation(s)
- Brennan Olson
- Medical Scientist Training ProgramOregon Health & Science UniversityPortlandORUSA
- Papé Family Pediatric Research InstituteOregon Health & Science UniversityPortlandORUSA
| | - Daniel L. Marks
- Papé Family Pediatric Research InstituteOregon Health & Science UniversityPortlandORUSA
- Brenden‐Colson Center for Pancreatic CareOregon Health & Science UniversityPortlandORUSA
| | - Aaron J. Grossberg
- Brenden‐Colson Center for Pancreatic CareOregon Health & Science UniversityPortlandORUSA
- Department of Radiation MedicineOregon Health & Science UniversityPortlandORUSA
- Cancer Early Detection Advanced Research CenterOregon Health & Science UniversityPortlandORUSA
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8
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Larson KR, Chaffin ATB, Goodson ML, Fang Y, Ryan KK. Fibroblast Growth Factor-21 Controls Dietary Protein Intake in Male Mice. Endocrinology 2019; 160:1069-1080. [PMID: 30802283 PMCID: PMC6469953 DOI: 10.1210/en.2018-01056] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 02/20/2019] [Indexed: 12/14/2022]
Abstract
Whereas carbohydrates and lipids are stored as glycogen and fat, there is no analogous inert storage form of protein. Therefore, continuous adjustments in feeding behavior are needed to match amino acid supply to ongoing physiologic need. Neuroendocrine mechanisms facilitating this behavioral control of protein and amino acid homeostasis remain unclear. The hepatokine fibroblast growth factor-21 (FGF21) is well positioned for such a role, as it is robustly secreted in response to protein and/or amino acid deficit. In this study, we tested the hypothesis that FGF21 feeds back at its receptors in the nervous system to shift macronutrient selection toward protein. In a series of behavioral tests, we isolated the effect of FGF21 to influence consumption of protein, fat, and carbohydrate in male mice. First, we used a three-choice pure macronutrient-diet paradigm. In response to FGF21, mice increased consumption of protein while reducing carbohydrate intake, with no effect on fat intake. Next, to determine whether protein or carbohydrate was the primary-regulated nutrient, we used a sequence of two-choice experiments to isolate the effect of FGF21 on preference for each macronutrient. Sweetness was well controlled by holding sucrose constant across the diets. Under these conditions, FGF21 increased protein intake, and this was offset by reducing the consumption of either carbohydrate or fat. When protein was held constant, FGF21 had no effect on macronutrient intake. Lastly, the effect of FGF21 to increase protein intake required the presence of its co-receptor, β-klotho, in neurons. Taken together, these findings point to a novel liver→nervous system pathway underlying the regulation of dietary protein intake via FGF21.
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Affiliation(s)
- Karlton R Larson
- Department of Neurobiology, Physiology, and Behavior, College of Biological Sciences, University of California, Davis, Davis, California
| | - Aki T-B Chaffin
- Department of Neurobiology, Physiology, and Behavior, College of Biological Sciences, University of California, Davis, Davis, California
| | - Michael L Goodson
- Department of Neurobiology, Physiology, and Behavior, College of Biological Sciences, University of California, Davis, Davis, California
| | - Yanbin Fang
- Department of Neurobiology, Physiology, and Behavior, College of Biological Sciences, University of California, Davis, Davis, California
| | - Karen K Ryan
- Department of Neurobiology, Physiology, and Behavior, College of Biological Sciences, University of California, Davis, Davis, California
- Correspondence: Karen K. Ryan, PhD, Department of Neurobiology, Physiology, and Behavior, University of California, Davis, 1 Shields Avenue, 196 Briggs Hall, Davis, California 95616. E-mail:
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9
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Al Koborssy D, Palouzier-Paulignan B, Canova V, Thevenet M, Fadool DA, Julliard AK. Modulation of olfactory-driven behavior by metabolic signals: role of the piriform cortex. Brain Struct Funct 2018; 224:315-336. [PMID: 30317390 DOI: 10.1007/s00429-018-1776-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/08/2018] [Indexed: 12/25/2022]
Abstract
Olfaction is one of the major sensory modalities that regulates food consumption and is in turn regulated by the feeding state. Given that the olfactory bulb has been shown to be a metabolic sensor, we explored whether the anterior piriform cortex (aPCtx)-a higher olfactory cortical processing area-had the same capacity. Using immunocytochemical approaches, we report the localization of Kv1.3 channel, glucose transporter type 4, and the insulin receptor in the lateral olfactory tract and Layers II and III of the aPCtx. In current-clamped superficial pyramidal (SP) cells, we report the presence of two populations of SP cells: glucose responsive and non-glucose responsive. Using varied glucose concentrations and a glycolysis inhibitor, we found that insulin modulation of the instantaneous and spike firing frequency are both glucose dependent and require glucose metabolism. Using a plethysmograph to record sniffing frequency, rats microinjected with insulin failed to discriminate ratiometric enantiomers; considered a difficult task. Microinjection of glucose prevented discrimination of odorants of different chain-lengths, whereas injection of margatoxin increased the rate of habituation to repeated odor stimulation and enhanced discrimination. These data suggest that metabolic signaling pathways that are present in the aPCtx are capable of neuronal modulation and changing complex olfactory behaviors in higher olfactory centers.
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Affiliation(s)
- Dolly Al Koborssy
- Program in Neuroscience, The Florida State University, Tallahassee, FL, USA.,Department of Biological Science, The Florida State University, Tallahassee, FL, USA
| | - Brigitte Palouzier-Paulignan
- Univ Lyon, Université Claude Bernard Lyon1, Centre de Recherche en Neurosciences de Lyon (CRNL), INSERM U1028/CNRS UMR5292 Team Olfaction: From Coding to Memory, 50 Av. Tony Garnier, 69366, Lyon, France
| | - Vincent Canova
- Univ Lyon, Université Claude Bernard Lyon1, Centre de Recherche en Neurosciences de Lyon (CRNL), INSERM U1028/CNRS UMR5292 Team Olfaction: From Coding to Memory, 50 Av. Tony Garnier, 69366, Lyon, France
| | - Marc Thevenet
- Univ Lyon, Université Claude Bernard Lyon1, Centre de Recherche en Neurosciences de Lyon (CRNL), INSERM U1028/CNRS UMR5292 Team Olfaction: From Coding to Memory, 50 Av. Tony Garnier, 69366, Lyon, France
| | - Debra Ann Fadool
- Program in Neuroscience, The Florida State University, Tallahassee, FL, USA.,Institute of Molecular Biophysics, The Florida State University, Tallahassee, FL, USA.,Department of Biological Science, The Florida State University, Tallahassee, FL, USA
| | - Andrée Karyn Julliard
- Univ Lyon, Université Claude Bernard Lyon1, Centre de Recherche en Neurosciences de Lyon (CRNL), INSERM U1028/CNRS UMR5292 Team Olfaction: From Coding to Memory, 50 Av. Tony Garnier, 69366, Lyon, France.
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10
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Gietzen DW, Lindström SH, Sharp JW, Teh PS, Donovan MJ. Indispensable Amino Acid-Deficient Diets Induce Seizures in Ketogenic Diet-Fed Rodents, Demonstrating a Role for Amino Acid Balance in Dietary Treatments for Epilepsy. J Nutr 2018; 148:480-489. [PMID: 29546295 PMCID: PMC6669944 DOI: 10.1093/jn/nxx030] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 08/21/2017] [Accepted: 10/30/2017] [Indexed: 11/13/2022] Open
Abstract
Background Low protein amounts are used in ketogenic diets (KDs), where an essential (indispensable) amino acid (IAA) can become limiting. Because the chemically sensitive, seizurogenic, anterior piriform cortex (APC) is excited by IAA limitation, an imbalanced KD could exacerbate seizure activity. Objective We questioned whether dietary IAA depletion worsens seizure activity in rodents fed KDs. Methods In a series of 6 trials, male rats or gerbils of both sexes (6-8/group) were given either control diets (CDs) appropriate for each trial, a KD, or a threonine-devoid (ThrDev) diet for ≥7 d, and tested for seizures using various stimuli. Microchip analysis of rat APCs was also used to determine if changes in transcripts for structures relevant to seizurogenesis are affected by a ThrDev diet. Glutamate release was measured in microdialysis samples from APCs during the first meal after 7 d on a CD or a ThrDev diet. Results Adult rats showed increased susceptibility to seizures in both chemical (58%) and electroshock (doubled) testing after 7 d on a ThrDev diet compared with CD (each trial, P ≤ 0.05). Seizure-prone Mongolian gerbils had fewer seizures after receiving a KD, but exacerbated seizures (68%) after 1 meal of KD minus Thr (KD-T compared with CD, P < 0.05). In kindled rats fed KD-T, both counts (19%) and severities (77%) of seizures were significantly elevated (KD-T compared with CD, P < 0.05). Gene transcript changes were consistent with enhanced seizure susceptibility (7-21 net-fold increases, P = 0.045-0.001) and glutamate release into the APC was increased acutely (4-fold at 20 min, 2.6-fold at 60 min, P < 0.05) after 7 d on a ThrDev diet. Conclusion Seizure severity in rats and gerbils was reduced after KDs and exacerbated by ThrDev, both in KD- and CD-fed animals, consistent with the mechanistic studies. We suggest that a complete protein profile in KDs may improve IAA balance in the APC, thereby lowering the risk of seizures.
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11
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Westmark CJ. A Role for Amino Acid Balance in Dietary Treatments for Epilepsy. J Nutr 2018; 148:307-308. [PMID: 29546299 DOI: 10.1093/jn/nxx044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 11/13/2017] [Indexed: 01/26/2023] Open
Affiliation(s)
- Cara J Westmark
- Department of Neurology, University of Wisconsin, Medical Sciences Center, Madison, WI
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12
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Rescue of impaired sociability and anxiety-like behavior in adult cacna1c-deficient mice by pharmacologically targeting eIF2α. Mol Psychiatry 2017; 22:1096-1109. [PMID: 28584287 PMCID: PMC5863913 DOI: 10.1038/mp.2017.124] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 04/12/2017] [Accepted: 05/04/2017] [Indexed: 12/13/2022]
Abstract
CACNA1C, encoding the Cav1.2 subunit of L-type Ca2+ channels, has emerged as one of the most prominent and highly replicable susceptibility genes for several neuropsychiatric disorders. Cav1.2 channels play a crucial role in calcium-mediated processes involved in brain development and neuronal function. Within the CACNA1C gene, disease-associated single-nucleotide polymorphisms have been associated with impaired social and cognitive processing and altered prefrontal cortical (PFC) structure and activity. These findings suggest that aberrant Cav1.2 signaling may contribute to neuropsychiatric-related disease symptoms via impaired PFC function. Here, we show that mice harboring loss of cacna1c in excitatory glutamatergic neurons of the forebrain (fbKO) that we have previously reported to exhibit anxiety-like behavior, displayed a social behavioral deficit and impaired learning and memory. Furthermore, focal knockdown of cacna1c in the adult PFC recapitulated the social deficit and elevated anxiety-like behavior, but not the deficits in learning and memory. Electrophysiological and molecular studies in the PFC of cacna1c fbKO mice revealed higher E/I ratio in layer 5 pyramidal neurons and lower general protein synthesis. This was concurrent with reduced activity of mTORC1 and its downstream mRNA translation initiation factors eIF4B and 4EBP1, as well as elevated phosphorylation of eIF2α, an inhibitor of mRNA translation. Remarkably, systemic treatment with ISRIB, a small molecule inhibitor that suppresses the effects of phosphorylated eIF2α on mRNA translation, was sufficient to reverse the social deficit and elevated anxiety-like behavior in adult cacna1c fbKO mice. ISRIB additionally normalized the lower protein synthesis and higher E/I ratio in the PFC. Thus this study identifies a novel Cav1.2 mechanism in neuropsychiatric-related endophenotypes and a potential future therapeutic target to explore.
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13
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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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14
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Heeley N, Blouet C. Central Amino Acid Sensing in the Control of Feeding Behavior. Front Endocrinol (Lausanne) 2016; 7:148. [PMID: 27933033 PMCID: PMC5120084 DOI: 10.3389/fendo.2016.00148] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 11/03/2016] [Indexed: 11/13/2022] Open
Abstract
Dietary protein quantity and quality greatly impact metabolic health via evolutionary-conserved mechanisms that ensure avoidance of amino acid imbalanced food sources, promote hyperphagia when dietary protein density is low, and conversely produce satiety when dietary protein density is high. Growing evidence supports the emerging concept of protein homeostasis in mammals, where protein intake is maintained within a tight range independently of energy intake to reach a target protein intake. The behavioral and neuroendocrine mechanisms underlying these adaptations are unclear. While peripheral factors are able to signal amino acid deficiency and abundance to the brain, the brain itself is exposed to and can detect changes in amino acid concentrations, and subsequently engages acute and chronic responses modulating feeding behavior and food preferences. In this review, we will examine the literature describing the mechanisms by which the brain senses changes in amino acids concentrations, and how these changes modulate feeding behavior.
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Affiliation(s)
- Nicholas Heeley
- Medical Research Council Metabolic Disease Unit, Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Clemence Blouet
- Medical Research Council Metabolic Disease Unit, Institute of Metabolic Science, University of Cambridge, Cambridge, UK
- *Correspondence: Clemence Blouet,
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15
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Leib DE, Knight ZA. Re-examination of Dietary Amino Acid Sensing Reveals a GCN2-Independent Mechanism. Cell Rep 2015; 13:1081-1089. [PMID: 26526991 PMCID: PMC4836942 DOI: 10.1016/j.celrep.2015.09.055] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 08/16/2015] [Accepted: 09/18/2015] [Indexed: 12/02/2022] Open
Abstract
Animals cannot synthesize nine essential amino acids (EAAs) and must therefore obtain them from food. Mice reportedly reject food lacking a single EAA within the first hour of feeding. This remarkable phenomenon is proposed to involve post-ingestive sensing of amino acid imbalance by the protein kinase GCN2 in the brain. Here, we systematically re-examine dietary amino acid sensing in mice. In contrast to previous results, we find that mice cannot rapidly identify threonine- or leucine-deficient food in common feeding paradigms. However, mice attain the ability to identify EAA-deficient food following 2 days of EAA deprivation, suggesting a requirement for physiologic need. In addition, we report that mice can rapidly identify lysine-deficient food without prior EAA deficit, revealing a distinct sensing mechanism for this amino acid. These behaviors are independent of the proposed amino acid sensor GCN2, pointing to the existence of an undescribed mechanism for rapid sensing of dietary EAAs.
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Affiliation(s)
- David E Leib
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Zachary A Knight
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA.
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16
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Morrison SF, Madden CJ. Central nervous system regulation of brown adipose tissue. Compr Physiol 2015; 4:1677-713. [PMID: 25428857 DOI: 10.1002/cphy.c140013] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Thermogenesis, the production of heat energy, in brown adipose tissue is a significant component of the homeostatic repertoire to maintain body temperature during the challenge of low environmental temperature in many species from mouse to man and plays a key role in elevating body temperature during the febrile response to infection. The sympathetic neural outflow determining brown adipose tissue (BAT) thermogenesis is regulated by neural networks in the CNS which increase BAT sympathetic nerve activity in response to cutaneous and deep body thermoreceptor signals. Many behavioral states, including wakefulness, immunologic responses, and stress, are characterized by elevations in core body temperature to which central command-driven BAT activation makes a significant contribution. Since energy consumption during BAT thermogenesis involves oxidation of lipid and glucose fuel molecules, the CNS network driving cold-defensive and behavioral state-related BAT activation is strongly influenced by signals reflecting the short- and long-term availability of the fuel molecules essential for BAT metabolism and, in turn, the regulation of BAT thermogenesis in response to metabolic signals can contribute to energy balance, regulation of body adipose stores and glucose utilization. This review summarizes our understanding of the functional organization and neurochemical influences within the CNS networks that modulate the level of BAT sympathetic nerve activity to produce the thermoregulatory and metabolic alterations in BAT thermogenesis and BAT energy expenditure that contribute to overall energy homeostasis and the autonomic support of behavior.
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Affiliation(s)
- Shaun F Morrison
- Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon
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17
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Olivo D, Caba M, Gonzalez-Lima F, Vázquez A, Corona-Morales A. Circadian feeding entrains anticipatory metabolic activity in piriform cortex and olfactory tubercle, but not in suprachiasmatic nucleus. Brain Res 2014; 1592:11-21. [PMID: 25281805 DOI: 10.1016/j.brainres.2014.09.054] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/11/2014] [Accepted: 09/23/2014] [Indexed: 10/24/2022]
Abstract
Animals maintained under conditions of food-availability restricted to a specific period of the day show molecular and physiological circadian rhythms and increase their locomotor activity 2-3h prior to the next scheduled feeding, called food anticipatory activity (FAA). Although the anatomical substrates and underlying mechanisms of the food-entrainable oscillator are not well understood, experimental evidence indicates that it involves multiple structures and systems. Using rabbit pups entrained to circadian nursing as a natural model of food restriction, we hypothesized that the anterior piriform cortex (APCx) and the olfactory tubercle (OTu) are activated during nursing-associated FAA. Two groups of litters were entrained to one of two different nursing times. At postnatal day 7, when litters showed clear FAA, pups from each litter were euthanized at nursing time, or 1, 2, 4, 8, 12, 16 or 20h later. Neural metabolic activities of the APCx, OTu, olfactory bulb (OB) and suprachiasmatic nucleus (SCN) were assessed by cytochrome oxidase histochemistry. Additionally, two fasted groups were nurse-deprived for two cycles before being euthanized at postnatal day 9. In nursed pups, metabolic activity of APCx, OTu and OB increased during FAA and after feeding, independently of the geographical time. Metabolic activity in SCN was not affected by nursing schedule. Given that APCx and OTu are in a key network position to integrate temporal odor signals with body energetic state, brain arousal and reward mechanisms, we suggest that these structures could be an important part of the conditioned oscillatory mechanism that leads to food entrainment.
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Affiliation(s)
- Diana Olivo
- Programa de Doctorado en Ciencias Biomédicas, Universidad Veracruzana, Xalapa, Ver., Mexico.
| | - Mario Caba
- Centro de Investigaciones Biomédicas, Universidad Veracruzana, Xalapa, Ver., Mexico.
| | - F Gonzalez-Lima
- Department of Psychology and Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA.
| | - Araceli Vázquez
- Programa de Doctorado en Ciencias Biomédicas, Universidad Veracruzana, Xalapa, Ver., Mexico.
| | - Aleph Corona-Morales
- Laboratorio de Investigación Genómica y Fisiológica, Facultad de Nutrición, Médicos y odontólogos s/n, Col. Unidad del Bosque, Universidad Veracruzana, 91010 Xalapa, Ver., Mexico.
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18
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Abbott JA, Francklyn CS, Robey-Bond SM. Transfer RNA and human disease. Front Genet 2014; 5:158. [PMID: 24917879 PMCID: PMC4042891 DOI: 10.3389/fgene.2014.00158] [Citation(s) in RCA: 149] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 05/14/2014] [Indexed: 12/25/2022] Open
Abstract
Pathological mutations in tRNA genes and tRNA processing enzymes are numerous and result in very complicated clinical phenotypes. Mitochondrial tRNA (mt-tRNA) genes are “hotspots” for pathological mutations and over 200 mt-tRNA mutations have been linked to various disease states. Often these mutations prevent tRNA aminoacylation. Disrupting this primary function affects protein synthesis and the expression, folding, and function of oxidative phosphorylation enzymes. Mitochondrial tRNA mutations manifest in a wide panoply of diseases related to cellular energetics, including COX deficiency (cytochrome C oxidase), mitochondrial myopathy, MERRF (Myoclonic Epilepsy with Ragged Red Fibers), and MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes). Diseases caused by mt-tRNA mutations can also affect very specific tissue types, as in the case of neurosensory non-syndromic hearing loss and pigmentary retinopathy, diabetes mellitus, and hypertrophic cardiomyopathy. Importantly, mitochondrial heteroplasmy plays a role in disease severity and age of onset as well. Not surprisingly, mutations in enzymes that modify cytoplasmic and mitochondrial tRNAs are also linked to a diverse range of clinical phenotypes. In addition to compromised aminoacylation of the tRNAs, mutated modifying enzymes can also impact tRNA expression and abundance, tRNA modifications, tRNA folding, and even tRNA maturation (e.g., splicing). Some of these pathological mutations in tRNAs and processing enzymes are likely to affect non-canonical tRNA functions, and contribute to the diseases without significantly impacting on translation. This chapter will review recent literature on the relation of mitochondrial and cytoplasmic tRNA, and enzymes that process tRNAs, to human disease. We explore the mechanisms involved in the clinical presentation of these various diseases with an emphasis on neurological disease.
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Affiliation(s)
- Jamie A Abbott
- Department of Biochemistry, College of Medicine, University of Vermont Burlington, VT, USA
| | | | - Susan M Robey-Bond
- Department of Biochemistry, College of Medicine, University of Vermont Burlington, VT, USA
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19
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Kamata S, Yamamoto J, Kamijo K, Ochiai T, Morita T, Yoshitomi Y, Hagiya Y, Kubota M, Ohkubo R, Kawaguchi M, Himi T, Kasahara T, Ishii I. Dietary deprivation of each essential amino acid induces differential systemic adaptive responses in mice. Mol Nutr Food Res 2014; 58:1309-21. [DOI: 10.1002/mnfr.201300758] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 01/24/2014] [Accepted: 01/26/2014] [Indexed: 12/13/2022]
Affiliation(s)
- Shotaro Kamata
- Department of Biochemistry; Keio University Graduate School of Pharmaceutical Sciences; Tokyo Japan
| | - Junya Yamamoto
- Department of Biochemistry; Keio University Graduate School of Pharmaceutical Sciences; Tokyo Japan
| | - Kenta Kamijo
- Department of Biochemistry; Keio University Graduate School of Pharmaceutical Sciences; Tokyo Japan
| | - Takahito Ochiai
- Department of Biochemistry; Keio University Graduate School of Pharmaceutical Sciences; Tokyo Japan
| | - Tamako Morita
- Department of Biochemistry; Keio University Graduate School of Pharmaceutical Sciences; Tokyo Japan
| | - Yurika Yoshitomi
- Department of Biochemistry; Keio University Graduate School of Pharmaceutical Sciences; Tokyo Japan
| | - Yoshifumi Hagiya
- Department of Biochemistry; Keio University Graduate School of Pharmaceutical Sciences; Tokyo Japan
| | - Masashi Kubota
- Department of Biochemistry; Keio University Graduate School of Pharmaceutical Sciences; Tokyo Japan
| | - Rika Ohkubo
- Department of Biochemistry; Keio University Graduate School of Pharmaceutical Sciences; Tokyo Japan
| | | | - Toshiyuki Himi
- Faculty of Pharmacy and Research Institute of Pharmaceutical Sciences; Musashino University; Tokyo Japan
| | - Tadashi Kasahara
- Department of Biochemistry; Keio University Graduate School of Pharmaceutical Sciences; Tokyo Japan
| | - Isao Ishii
- Department of Biochemistry; Keio University Graduate School of Pharmaceutical Sciences; Tokyo Japan
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20
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Sharp JW, Ross-Inta CM, Baccelli I, Payne JA, Rudell JB, Gietzen DW. Effects of essential amino acid deficiency: down-regulation of KCC2 and the GABAA receptor; disinhibition in the anterior piriform cortex. J Neurochem 2013; 127:520-30. [PMID: 24024616 PMCID: PMC3858386 DOI: 10.1111/jnc.12403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 08/14/2013] [Accepted: 08/15/2013] [Indexed: 01/27/2023]
Abstract
The anterior piriform cortex (APC) is activated by, and is the brain area most sensitive to, essential (indispensable) amino acid (IAA) deficiency. The APC is required for the rapid (20 min) behavioral rejection of IAA deficient diets and increased foraging, both crucial adaptive functions supporting IAA homeostasis in omnivores. The biochemical mechanisms signaling IAA deficiency in the APC block initiation of translation in protein synthesis via uncharged tRNA and the general amino acid control kinase, general control nonderepressing kinase 2. Yet, how inhibition of protein synthesis activates the APC is unknown. The neuronal K(+) Cl(-) cotransporter, neural potassium chloride co-transporter (KCC2), and GABAA receptors are essential inhibitory elements in the APC with short plasmalemmal half-lives that maintain control in this highly excitable circuitry. After a single IAA deficient meal both proteins were reduced (vs. basal diet controls) in western blots of APC (but not neocortex or cerebellum) and in immunohistochemistry of APC. Furthermore, electrophysiological analyses support loss of inhibitory elements such as the GABAA receptor in this model. As the crucial inhibitory function of the GABAA receptor depends on KCC2 and the Cl(-) transmembrane gradient it establishes, these results suggest that loss of such inhibitory elements contributes to disinhibition of the APC in IAA deficiency. The circuitry of the anterior piriform cortex (APC) is finely balanced between excitatory (glutamate, +) and inhibitory (GABA, -) transmission. GABAA receptors use Cl(-), requiring the neural potassium chloride co-transporter (KCC2). Both are rapidly turning-over proteins, dependent on protein synthesis for repletion. In IAA (indispensable amino acid) deficiency, within 20 min, blockade of protein synthesis prevents restoration of these inhibitors; they are diminished; disinhibition ensues. GCN2 = general control non-derepressing kinase 2, eIF2α = α-subunit of the eukaryotic initiation factor 2.
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Affiliation(s)
- James W. Sharp
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, One Shields Ave, Davis CA 95616, USA, Voice +530-752-1174, Fax +530-752-7690
| | - Catherine M. Ross-Inta
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, One Shields Ave, Davis CA 95616, USA, Voice +530-752-1174, Fax +530-752-7690
| | - Irène Baccelli
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, One Shields Ave, Davis CA 95616, USA, Voice +530-752-1174, Fax +530-752-7690
| | - John A. Payne
- Physiology and Membrane Biology, School of Medicine, University of California, Davis, CA 95616, USA, Voice +1 530 752 3336, FAX +1 530 752 5423
| | - John B. Rudell
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, One Shields Ave, Davis CA 95616, USA, Voice +530-752-1174, Fax +530-752-7690
| | - Dorothy W. Gietzen
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, One Shields Ave, Davis CA 95616, USA, Voice +530-752-1174, Fax +530-752-7690
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21
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Abstract
PURPOSE OF REVIEW To understand the principles of amino acid deprivation sensing in the brain and its behavioral and metabolic outcomes with an emphasis on the current literature. RECENT FINDINGS Sensing essential amino acid (EAA) depletion occurs in the anterior piriform cortex (APC) via general control nonderepressible 2 (GCN2) binding to deacylated tRNA and subsequent glutamatergic signaling to influence behavior. Mapping of the APC output during EAA insufficiency shows axons projecting to the hypothalamus as well as other regions that are involved in feeding and locomotion. Whereas these neurocircuits are clearly important in regulating anorectic responses to an EAA-devoid diet, the propagating events and regulatory factors are still unclear. Recently, several groups examined signaling and gene expression in the arcuate nucleus and lateral hypothalamus during EAA deficiency. In these efforts, several gene products, including somatostatin, corticotrophin-releasing hormone, neuropeptide Y, agouti-related protein, and several novel targets were identified as factors involved in regulating the aversion to EAA-deficient diets. On a different note, marginal EAA deficiency in the form of methionine restriction promotes hyperphagia similar to low-protein diets, yet animals are leaner and live longer. The central mechanisms are unclear but involve sympathetic nervous signaling. How and why different degrees of EAA deficiency cause opposite changes in behavior and body composition require further study. SUMMARY Scientific inquiry into the central mechanism by which EAA insufficiency is sensed has identified the APC as the brain's initial EAA chemosensor. Beyond this, much remains uncertain. Future investigation into the signaling and gene expression events occurring in the hypothalamus and other brain regions is warranted.
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Affiliation(s)
- Tracy G Anthony
- Department of Nutritional Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, USA.
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22
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Zhu X, Krasnow SM, Roth-Carter QR, Levasseur PR, Braun TP, Grossberg AJ, Marks DL. Hypothalamic signaling in anorexia induced by indispensable amino acid deficiency. Am J Physiol Endocrinol Metab 2012; 303:E1446-58. [PMID: 23047987 PMCID: PMC3532465 DOI: 10.1152/ajpendo.00427.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Animals exhibit a rapid and sustained anorexia when fed a diet that is deficient in a single indispensable amino acid (IAA). The chemosensor for IAA deficiency resides within the anterior piriform cortex (APC). Although the cellular and molecular mechanisms by which the APC detects IAA deficiency are well established, the efferent neural pathways that reduce feeding in response to an IAA-deficient diet remain to be fully characterized. In the present work, we investigated whether 1) central melanocortin signaling is involved in IAA deficiency-induced anorexia (IAADA) and 2) IAADA engages other key appetite-regulating neuronal populations in the hypothalamus. Rats and mice that consumed a valine-deficient diet (VDD) for 2-3 wk exhibited marked reductions in food intake, body weight, fat and lean body mass, body temperature, and white adipose tissue leptin gene expression, as well as a paradoxical increase in brown adipose tissue uncoupling protein-1 mRNA. Animals consuming the VDD had altered hypothalamic gene expression, typical of starvation. Pharmacological and genetic blockade of central melanocortin signaling failed to increase long-term food intake in this model. Chronic IAA deficiency was associated with a marked upregulation of corticotropin-releasing hormone expression in the lateral hypothalamus, particularly in the parasubthalamic nucleus, an area heavily innervated by efferent projections from the APC. Our observations indicate that the hypothalamic melanocortin system plays a minor role in acute, but not chronic, IAADA and suggest that the restraint on feeding is analogous to that observed after chronic dehydration.
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Affiliation(s)
- Xinxia Zhu
- Papé Family Pediatric Research Institute, Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239, USA
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23
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The brain's response to an essential amino acid-deficient diet and the circuitous route to a better meal. Mol Neurobiol 2012; 46:332-48. [PMID: 22674217 DOI: 10.1007/s12035-012-8283-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 05/24/2012] [Indexed: 12/16/2022]
Abstract
The essential (indispensable) amino acids (IAA) are neither synthesized nor stored in metazoans, yet they are the building blocks of protein. Survival depends on availability of these protein precursors, which must be obtained in the diet; it follows that food selection is critical for IAA homeostasis. If even one of the IAA is depleted, its tRNA becomes quickly deacylated and the levels of charged tRNA fall, leading to disruption of global protein synthesis. As they have priority in the diet, second only to energy, the missing IAA must be restored promptly or protein catabolism ensues. Animals detect and reject an IAA-deficient meal in 20 min, but how? Here, we review the molecular basis for sensing IAA depletion and repletion in the brain's IAA chemosensor, the anterior piriform cortex (APC). As animals stop eating an IAA-deficient meal, they display foraging and altered choice behaviors, to improve their chances of encountering a better food. Within 2 h, sensory cues are associated with IAA depletion or repletion, leading to learned aversions and preferences that support better food selection. We show neural projections from the APC to appetitive and consummatory motor control centers, and to hedonic, motivational brain areas that reinforce these adaptive behaviors.
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Abstract
There is considerable disagreement regarding what constitutes a healthy diet. Ever since the influential work of Cannon and Richter, it was debated whether the 'wisdom of the body' will automatically direct us to the foods we need for healthy lives or whether we must carefully learn to eat the right foods, particularly in an environment of plenty. Although it is clear that strong mechanisms have evolved to prevent consumption of foods that have previously made us sick, it is less clear whether reciprocal mechanisms exist that reinforce the consumption of healthy diets. Here, we review recent progress in providing behavioural evidence for the regulation of intake and selection of proteins, carbohydrates and fats. We examine new developments in sensory physiology enabling recognition of macronutrients both pre- and post-ingestively. Finally, we propose a general model for central neural processing of nutrient-specific appetites. We suggest that the same basic neural circuitry responsible for the homoeostatic regulation of total energy intake is also used to control consumption of specific macro- and micronutrients. Similar to salt appetite, specific appetites for other micro- and macronutrients may be encoded by unique molecular changes in the hypothalamus. Gratification of such specific appetites is then accomplished by engaging the brain motivational system to assign the highest reward prediction to exteroceptive cues previously associated with consuming the missing ingredient. A better understanding of these nutrient-specific neural processes could help design drugs and behavioural strategies that promote healthier eating.
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Morrison CD, Reed SD, Henagan TM. Homeostatic regulation of protein intake: in search of a mechanism. Am J Physiol Regul Integr Comp Physiol 2012; 302:R917-28. [PMID: 22319049 DOI: 10.1152/ajpregu.00609.2011] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Free-living organisms must procure adequate nutrition by negotiating an environment in which both the quality and quantity of food vary markedly. Recent decades have seen marked progress in our understanding of neural regulation of feeding behavior. However, this progress has occurred largely in the context of energy intake, despite the fact that food intake is influenced by more than just the energy content of the diet. A large number of behavioral studies indicate that both the quantity and quality of dietary protein can markedly influence food intake. High-protein diets tend to reduce intake, low-protein diets tend to increase intake, and rodent models seem to self-select between diets in order to meet protein requirements and avoid diets that are imbalanced in amino acids. Recent work suggests that the amino acid leucine regulates food intake by altering mTOR and AMPK signaling in the hypothalamus, while activation of GCN2 within the anterior piriform cortex contributes to the detection and avoidance of amino acid-imbalanced diets. This review focuses on the role that these and other signaling systems may play in mediating the homeostatic regulation of protein balance, and in doing so, highlights our lack of knowledge regarding the physiological and neurobiological mechanisms that might underpin such a regulatory phenomenon.
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Purpera MN, Shen L, Taghavi M, Münzberg H, Martin RJ, Hutson SM, Morrison CD. Impaired branched chain amino acid metabolism alters feeding behavior and increases orexigenic neuropeptide expression in the hypothalamus. J Endocrinol 2012; 212:85-94. [PMID: 21969404 PMCID: PMC3350378 DOI: 10.1530/joe-11-0270] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
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 hypothalamic Npy and Agrp mRNA. Normalization of circulating leptin levels had no effect on either food preference or the increased Npy and Agrp mRNA 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.
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Affiliation(s)
| | - Li Shen
- Pennington Biomedical Research Center, Baton Rouge, La 70808
| | - Marzieh Taghavi
- Department of Human Nutrition, Foods & Exercise, Virginia Polytechnic Institute, Blacksburg, Virginia 24061
| | - Heike Münzberg
- Pennington Biomedical Research Center, Baton Rouge, La 70808
| | - Roy J. Martin
- Pennington Biomedical Research Center, Baton Rouge, La 70808
| | - Susan M. Hutson
- Department of Human Nutrition, Foods & Exercise, Virginia Polytechnic Institute, Blacksburg, Virginia 24061
| | - Christopher D. Morrison
- Pennington Biomedical Research Center, Baton Rouge, La 70808
- Corresponding Author and to whom reprint requests should be addressed: Christopher D. Morrison, Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, , 225-763-3145
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27
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Narita K, Nagao K, Bannai M, Ichimaru T, Nakano S, Murata T, Higuchi T, Takahashi M. Dietary deficiency of essential amino acids rapidly induces cessation of the rat estrous cycle. PLoS One 2011; 6:e28136. [PMID: 22132231 PMCID: PMC3223240 DOI: 10.1371/journal.pone.0028136] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 11/02/2011] [Indexed: 01/07/2023] Open
Abstract
Reproductive functions are regulated by the sophisticated coordination between the neuronal and endocrine systems and are sustained by a proper nutritional environment. Female reproductive function is vulnerable to effects from dietary restrictions, suggesting a transient adaptation that prioritizes individual survival over reproduction until a possible future opportunity for satiation. This adaptation could also partially explain the existence of amenorrhea in women with anorexia nervosa. Because amino acid nutritional conditions other than caloric restriction uniquely alters amino acid metabolism and affect the hormonal levels of organisms, we hypothesized that the supply of essential amino acids in the diet plays a pivotal role in the maintenance of the female reproductive system. To test this hypothesis, we examined ovulatory cyclicity in female rats under diets that were deficient in threonine, lysine, tryptophan, methionine or valine. Ovulatory cyclicity was monitored by daily cytological evaluations of vaginal smears. After continuous feeding of the deficient diet, a persistent diestrus or anovulatory state was induced most quickly by the valine-deficient diet and most slowly by the lysine-deficient diet. A decline in the systemic insulin-like growth factor 1 level was associated with a dietary amino acid deficiency. Furthermore, a paired group of rats that were fed an isocaloric diet with balanced amino acids maintained normal estrous cyclicity. These disturbances of the estrous cycle by amino acid deficiency were quickly reversed by the consumption of a normal diet. The continuous anovulatory state in this study is not attributable to a decrease in caloric intake but to an imbalance in the dietary amino acid composition. With a shortage of well-balanced amino acid sources, reproduction becomes risky for both the mother and the fetus. It could be viewed as an adaptation to the diet, diverting resources away from reproduction and reallocating them to survival until well-balanced amino acid sources are found.
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Affiliation(s)
- Kazumi Narita
- Department of Integrative Physiology, Faculty of Medical Sciences, University of Fukui, Yoshida-gun, Fukui, Japan
| | - Kenji Nagao
- Frontier Research Labs, Institute for Innovation, Ajinomoto Co., Inc., Kawasaki-shi, Kanagawa, Japan
| | - Makoto Bannai
- Frontier Research Labs, Institute for Innovation, Ajinomoto Co., Inc., Kawasaki-shi, Kanagawa, Japan
- * E-mail:
| | - Toru Ichimaru
- Department of Integrative Physiology, Faculty of Medical Sciences, University of Fukui, Yoshida-gun, Fukui, Japan
| | - Sayako Nakano
- Frontier Research Labs, Institute for Innovation, Ajinomoto Co., Inc., Kawasaki-shi, Kanagawa, Japan
| | - Takuya Murata
- Department of Integrative Physiology, Faculty of Medical Sciences, University of Fukui, Yoshida-gun, Fukui, Japan
| | - Takashi Higuchi
- Department of Integrative Physiology, Faculty of Medical Sciences, University of Fukui, Yoshida-gun, Fukui, Japan
| | - Michio Takahashi
- Frontier Research Labs, Institute for Innovation, Ajinomoto Co., Inc., Kawasaki-shi, Kanagawa, Japan
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Wassum KM, Ostlund SB, Balleine BW, Maidment NT. Differential dependence of Pavlovian incentive motivation and instrumental incentive learning processes on dopamine signaling. Learn Mem 2011; 18:475-83. [PMID: 21693635 DOI: 10.1101/lm.2229311] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Here we attempted to clarify the role of dopamine signaling in reward seeking. In Experiment 1, we assessed the effects of the dopamine D(1)/D(2) receptor antagonist flupenthixol (0.5 mg/kg i.p.) on Pavlovian incentive motivation and found that flupenthixol blocked the ability of a conditioned stimulus to enhance both goal approach and instrumental performance (Pavlovian-to-instrumental transfer). In Experiment 2 we assessed the effects of flupenthixol on reward palatability during post-training noncontingent re-exposure to the sucrose reward in either a control 3-h or novel 23-h food-deprived state. Flupenthixol, although effective in blocking the Pavlovian goal approach, was without effect on palatability or the increase in reward palatability induced by the upshift in motivational state. This noncontingent re-exposure provided an opportunity for instrumental incentive learning, the process by which rats encode the value of a reward for use in updating reward-seeking actions. Flupenthixol administered prior to the instrumental incentive learning opportunity did not affect the increase in subsequent off-drug reward-seeking actions induced by that experience. These data suggest that although dopamine signaling is necessary for Pavlovian incentive motivation, it is not necessary for changes in reward experience, or for the instrumental incentive learning process that translates this experience into the incentive value used to drive reward-seeking actions, and provide further evidence that Pavlovian and instrumental incentive learning processes are dissociable.
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Affiliation(s)
- Kate M Wassum
- Department of Psychiatry & Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, California 90024, USA.
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In brief. Nat Rev Neurosci 2011. [DOI: 10.1038/nrn3004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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