101
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A neural circuit mechanism for mechanosensory feedback control of ingestion. Nature 2020; 580:376-380. [DOI: 10.1038/s41586-020-2167-2] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 02/07/2020] [Indexed: 12/14/2022]
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102
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TrkB-expressing paraventricular hypothalamic neurons suppress appetite through multiple neurocircuits. Nat Commun 2020; 11:1729. [PMID: 32265438 PMCID: PMC7138837 DOI: 10.1038/s41467-020-15537-w] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 03/12/2020] [Indexed: 01/19/2023] Open
Abstract
The TrkB receptor is critical for the control of energy balance, as mutations in its gene (NTRK2) lead to hyperphagia and severe obesity. The main neural substrate mediating the appetite-suppressing activity of TrkB, however, remains unknown. Here, we demonstrate that selective Ntrk2 deletion within paraventricular hypothalamus (PVH) leads to severe hyperphagic obesity. Furthermore, chemogenetic activation or inhibition of TrkB-expressing PVH (PVHTrkB) neurons suppresses or increases food intake, respectively. PVHTrkB neurons project to multiple brain regions, including ventromedial hypothalamus (VMH) and lateral parabrachial nucleus (LPBN). We find that PVHTrkB neurons projecting to LPBN are distinct from those to VMH, yet Ntrk2 deletion in PVH neurons projecting to either VMH or LPBN results in hyperphagia and obesity. Additionally, TrkB activation with BDNF increases firing of these PVH neurons. Therefore, TrkB signaling is a key regulator of a previously uncharacterized neuronal population within the PVH that impinges upon multiple circuits to govern appetite. The TrkB receptor is known to regulate obesity via appetite control, but the underlying neural circuits are not known. Here, the authors show that selective modulation of TrkB+ neurons in the paraventricular hypothalamus regulates food intake via circuits to ventromedial hypothalamus and lateral parabrachial nucleus.
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103
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Sutton AK, Gonzalez IE, Sadagurski M, Rajala M, Lu C, Allison MB, Adams JM, Myers MG, White MF, Olson DP. Paraventricular, subparaventricular and periventricular hypothalamic IRS4-expressing neurons are required for normal energy balance. Sci Rep 2020; 10:5546. [PMID: 32218485 PMCID: PMC7099088 DOI: 10.1038/s41598-020-62468-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 03/12/2020] [Indexed: 02/07/2023] Open
Abstract
Understanding the neural components modulating feeding-related behavior and energy expenditure is crucial to combating obesity and its comorbidities. Neurons within the paraventricular nucleus of the hypothalamus (PVH) are a key component of the satiety response; activation of the PVH decreases feeding and increases energy expenditure, thereby promoting negative energy balance. In contrast, PVH ablation or silencing in both rodents and humans leads to substantial obesity. Recent studies have identified genetically-defined PVH subpopulations that control discrete aspects of energy balance (e.g. oxytocin (OXT), neuronal nitric oxide synthase 1 (NOS1), melanocortin 4-receptor (MC4R), prodynorphin (PDYN)). We previously demonstrated that non-OXT NOS1PVH neurons contribute to PVH-mediated feeding suppression. Here, we identify and characterize a non-OXT, non-NOS1 subpopulation of PVH and peri-PVH neurons expressing insulin-receptor substrate 4 (IRS4PVH) involved in energy balance control. Using Cre-dependent viral tools to activate, trace and silence these neurons, we highlight the sufficiency and necessity of IRS4PVH neurons in normal feeding and energy expenditure regulation. Furthermore, we demonstrate that IRS4PVH neurons lie within a complex hypothalamic circuitry that engages distinct hindbrain regions and is innervated by discrete upstream hypothalamic sites. Overall, we reveal a requisite role for IRS4PVH neurons in PVH-mediated energy balance which raises the possibility of developing novel approaches targeting IRS4PVH neurons for anti-obesity therapies.
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Affiliation(s)
- Amy K Sutton
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Ian E Gonzalez
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | | | - Michael Rajala
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Chunxia Lu
- Division of Pediatric Endocrinology, Department of Pediatrics, Michigan Medicine, Ann Arbor, MI, USA
| | - Margaret B Allison
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Jessica M Adams
- Division of Pediatric Endocrinology, Department of Pediatrics, Michigan Medicine, Ann Arbor, MI, USA
| | - Martin G Myers
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.,Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Morris F White
- Department of Endocrinology, Children's Hospital Boston, Boston, MA, USA
| | - David P Olson
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA. .,Division of Pediatric Endocrinology, Department of Pediatrics, Michigan Medicine, Ann Arbor, MI, USA.
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104
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Response of the expression of oxytocin neurons to ghrelin in female mice. Exp Brain Res 2020; 238:1085-1095. [PMID: 32215671 DOI: 10.1007/s00221-020-05793-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 03/18/2020] [Indexed: 12/17/2022]
Abstract
Ghrelin is an orexigenic agonist that acts directly on neurons in the hypothalamus, controlling appetite and energy balance. Although its role in appetite-associated neurons has been described, the relationship between peripheral ghrelin stimulation and oxytocin expression in the paraventricular nucleus is not fully understood. We evaluated the suppressive function of ghrelin in oxytocin-positive paraventricular nucleus neurons in ovariectomized C57BL/6 mice 2 h after ghrelin injection. The results showed that, in intact mice, peripheral ghrelin stimulation activated estrogen receptor alpha-expressing neurons during the estrous cycle and that agouti-related peptide mRNA expression was remarkably increased. Agouti-related peptide neuron axons co-localized with oxytocin neurons in the paraventricular nucleus. Moreover, the response of oxytocin-positive paraventricular nucleus neurons to ghrelin was suppressed in the proestrus period, while ghrelin decreased the serum concentration of estradiol in the proestrus phase. These data suggest that ghrelin may suppress oxytocin-positive neuron expression via the arcuate nucleus agouti-related peptide circuit, with the possible influence of estradiol in the murine estrous cycle. Unraveling the mechanism of ghrelin-induced oxytocin expression in the hypothalamus paraventricular nucleus broadens the horizon for ghrelin-related appetite research.
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105
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Xiao C, Liu N, Province H, Piñol RA, Gavrilova O, Reitman ML. BRS3 in both MC4R- and SIM1-expressing neurons regulates energy homeostasis in mice. Mol Metab 2020; 36:100969. [PMID: 32229422 PMCID: PMC7113433 DOI: 10.1016/j.molmet.2020.02.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/13/2020] [Accepted: 02/22/2020] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVE Bombesin-like receptor 3 (BRS3) is an orphan receptor and Brs3 knockout mice develop obesity with increased food intake and reduced resting metabolic rate and body temperature. The neuronal populations contributing to these effects were examined. METHODS We studied energy metabolism in mice with Cre-mediated recombination causing 1) loss of BRS3 selectively in SIM1- or MC4R-expressing neurons or 2) selective re-expression of BRS3 from a null background in these neurons. RESULTS The deletion of BRS3 in MC4R neurons increased body weight/adiposity, metabolic efficiency, and food intake, and reduced insulin sensitivity. BRS3 re-expression in these neurons caused partial or no reversal of these traits. However, these observations were confounded by an obesity phenotype caused by the Mc4r-Cre allele, independent of its recombinase activity. The deletion of BRS3 in SIM1 neurons increased body weight/adiposity and food intake, but not to the levels of the global null. The re-expression of BRS3 in SIM1 neurons reduced body weight/adiposity and food intake, but not to wild type levels. The deletion of BRS3 in either MC4R- or SIM1-expressing neurons affected body temperature, with re-expression in either population reversing the null phenotype. MK-5046, a BRS3 agonist, increases light phase body temperature in wild type, but not Brs3 null, mice and BRS3 re-expression in either population restored response to MK-5046. CONCLUSIONS BRS3 in both MC4R- and SIM1-expressing neurons contributes to regulation of body weight/adiposity, insulin sensitivity, food intake, and body temperature.
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Affiliation(s)
- Cuiying Xiao
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Naili Liu
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Haley Province
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Ramón A Piñol
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Oksana Gavrilova
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Marc L Reitman
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA.
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106
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Gavini CK, Cook TM, Rademacher DJ, Mansuy-Aubert V. Hypothalamic C2-domain protein involved in MC4R trafficking and control of energy balance. Metabolism 2020; 102:153990. [PMID: 31666192 DOI: 10.1016/j.metabol.2019.153990] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/12/2019] [Accepted: 10/02/2019] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Rates of overweight and obesity epidemic have risen significantly in the past few decades, and 34% of adults and 15-20% of children and adolescents in the United States are now obese. Melanocortin receptor 4 (MC4R), contributes to appetite control in hypothalamic neurons and is a target for future anti-obesity treatments (such as setmelanotide) or novel drug development effort. Proper MC4R trafficking regulation in hypothalamic neurons is crucial for normal neural control of homeostasis and is altered in obesity and in presence of lipids. The mechanisms underlying altered MC4R trafficking in the context of obesity is still unclear. Here, we discovered that C2CD5 expressed in the hypothalamus is involved in the regulation of MC4R endocytosis. This study unmasked a novel trafficking protein nutritionally regulated in the hypothalamus providing a novel target for MC4R dependent pathways involved in bodyweight homeostasis and Obesity. METHODS To evaluate the expression of C2cd5, we first used in situ hybridization and RNAscope technology in combination with electronic microscopy. For in vivo, we characterized the energy balance of wild type (WT) and C2CD5 whole-body knockout (C2CD5KO) mice fed normal chow (NC) and/or western-diet (high-fat/high-sucrose/cholesterol) (WD). To this end, we performed comprehensive longitudinal assessment of bodyweight, energy balance (food intake, energy expenditure, locomotor activity using TSE metabolic cages), and glucose homeostasis. In addition, we evaluated the consequence of loss of C2CD5 on feeding behavior changes normally induced by MC4R agonist (Melanotan, MTII) injection in the paraventricular hypothalamus (PVH). For in vitro approach, we tease out the role of C2CD5 and its calcium sensing domain C2 in MC4R trafficking. We focused on endocytosis of MC4R using an antibody feeding experiment (in a neuronal cell line - Neuro2A (N2A) stably expressing HA-MC4R-GFP; against HA-tag and analyzed by flux cytometry). RESULTS We found that 1) the expression of hypothalamic C2CD5 is decreased in diet-induced obesity models compared to controls, 2) mice lacking C2CD5 exhibit an increase in food intake compared to WT mice, 3) C2CD5 interacts with endocytosis machinery in hypothalamus, 4) loss of functional C2CD5 (lacking C2 domain) blunts MC4R endocytosis in vitro and increases MC4R at the surface that fails to respond to MC4R ligand, and, 5) C2CD5KO mice exhibit decreased acute responses to MTII injection into the PVH. CONCLUSIONS Based on these, we conclude that hypothalamic C2CD5 is involved in MC4R endocytosis and regulate bodyweight homeostasis. These studies suggest that C2CD5 represents a new protein regulated by metabolic cues and involved in metabolic receptor endocytosis. C2CD5 represent a new target and pathway that could be targeted in Obesity.
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Affiliation(s)
- Chaitanya K Gavini
- Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA
| | - Tyler M Cook
- Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA
| | - David J Rademacher
- Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA
| | - Virginie Mansuy-Aubert
- Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA.
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107
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Rodriguez E, Ryu D, Zhao S, Han BX, Wang F. Identifying Parabrachial Neurons Selectively Regulating Satiety for Highly Palatable Food in Mice. eNeuro 2019; 6:ENEURO.0252-19.2019. [PMID: 31662323 PMCID: PMC6868176 DOI: 10.1523/eneuro.0252-19.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 10/10/2019] [Accepted: 10/17/2019] [Indexed: 01/06/2023] Open
Abstract
Food consumption is necessary for organisms to maintain metabolic homeostasis. Both extrinsic and intrinsic processes, relayed via intricate neural circuitry, orchestrate the initiation and termination of food intake. More specifically, there are functionally distinct neural circuits that mediate either homeostatic or hedonic suppression of feeding. Notably, being satiated is a positive feeling whereas food aversion is a negative feeling. While significant progress has been made toward elucidating neural circuitry underlying aversive appetite suppression in mice, the circuitry underlying homeostatic satiety is not fully understood. The lateral parabrachial nucleus (PBL) is known as a node that regulates various sensory and visceral processes. Here, we identified and selectively labeled neurons in the caudal lateral region of PBL (PBcl) that are activated by consumption of condensed milk, chocolate Ensure, or peanut butter, which we refer to as PBcl-palatable-food activated neurons (PANs). Specific optogenetic activation of PANs induced positive place preference but decreased the consumption of high-caloric foods such as condensed milk, whereas silencing these cells significantly increased condensed milk consumption in feeding assays. Thus, the PBcl PANs revealed here represent a novel neural substrate regulating caloric-sufficiency mediated satiation.
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Affiliation(s)
- Erica Rodriguez
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27708
| | - David Ryu
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27708
| | - Shengli Zhao
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27708
| | - Bao-Xia Han
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27708
| | - Fan Wang
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27708
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108
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Abstract
The paraventricular hypothalamus (PVH) plays a pivotal role in regulating energy balance, though circuit mechanisms remain obscure. In this issue of Neuron, Li et al. (2019b) identify a circuit involving PVHPDYN neurons that, separately and synergistically with PVHMC4R neurons, controls feeding behaviors.
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Affiliation(s)
- Luis Varela
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06510, USA; Program of Integrative Cell Signaling and Neurobiology of Metabolism (ICSNM), Yale University School of Medicine, New Haven, CT 06510, USA
| | - Tamas L Horvath
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06510, USA; Program of Integrative Cell Signaling and Neurobiology of Metabolism (ICSNM), Yale University School of Medicine, New Haven, CT 06510, USA; Department of Anatomy and Histology, University of Veterinary Medicine, Budapest, Hungary.
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109
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Lewis S. Double satiety. Nat Rev Neurosci 2019; 20:252. [DOI: 10.1038/s41583-019-0164-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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