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Basu R, Elmendorf AJ, Lorentz B, Mahler CA, Lazzaro O, App B, Zhou S, Yamamoto Y, Suber M, Wann JC, Roh HC, Sheets PL, Johnson TS, Flak JN. Ventromedial hypothalamic nucleus subset stimulates tissue thermogenesis via preoptic area outputs. Mol Metab 2024; 84:101951. [PMID: 38729241 PMCID: PMC11112375 DOI: 10.1016/j.molmet.2024.101951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 04/20/2024] [Accepted: 04/27/2024] [Indexed: 05/12/2024] Open
Abstract
OBJECTIVE Hypothalamic signals potently stimulate energy expenditure by engaging peripheral mechanisms to restore energy homeostasis. Previous studies have identified several critical hypothalamic sites (e.g. preoptic area (POA) and ventromedial hypothalamic nucleus (VMN)) that could be part of an interconnected neurocircuit that controls tissue thermogenesis and essential for body weight control. However, the key neurocircuit that can stimulate energy expenditure has not yet been established. METHODS Here, we investigated the downstream mechanisms by which VMN neurons stimulate adipose tissue thermogenesis. We manipulated subsets of VMN neurons acutely as well as chronically and studied its effect on tissue thermogenesis and body weight control, using Sf1Cre and Adcyap1Cre mice and measured physiological parameters under both high-fat diet and standard chow diet conditions. To determine the node efferent to these VMN neurons, that is involved in modulating energy expenditure, we employed electrophysiology and optogenetics experiments combined with measurements using tissue-implantable temperature microchips. RESULTS Activation of the VMN neurons that express the steroidogenic factor 1 (Sf1; VMNSf1 neurons) reduced body weight, adiposity and increased energy expenditure in diet-induced obese mice. This function is likely mediated, at least in part, by the release of the pituitary adenylate cyclase-activating polypeptide (PACAP; encoded by the Adcyap1 gene) by the VMN neurons, since we previously demonstrated that PACAP, at the VMN, plays a key role in energy expenditure control. Thus, we then shifted focus to the subpopulation of VMNSf1 neurons that contain the neuropeptide PACAP (VMNPACAP neurons). Since the VMN neurons do not directly project to the peripheral tissues, we traced the location of the VMNPACAP neurons' efferents. We identified that VMNPACAP neurons project to and activate neurons in the caudal regions of the POA whereby these projections stimulate tissue thermogenesis in brown and beige adipose tissue. We demonstrated that selective activation of caudal POA projections from VMNPACAP neurons induces tissue thermogenesis, most potently in negative energy balance and activating these projections lead to some similar, but mostly unique, patterns of gene expression in brown and beige tissue. Finally, we demonstrated that the activation of the VMNPACAP neurons' efferents that lie at the caudal POA are necessary for inducing tissue thermogenesis in brown and beige adipose tissue. CONCLUSIONS These data indicate that VMNPACAP connections with the caudal POA neurons impact adipose tissue function and are important for induction of tissue thermogenesis. Our data suggests that the VMNPACAP → caudal POA neurocircuit and its components are critical for controlling energy balance by activating energy expenditure and body weight control.
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Affiliation(s)
- Rashmita Basu
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, USA; Lilly Diabetes Research Center, Indiana Biosciences Research Institute, Indianapolis, IN, USA
| | - Andrew J Elmendorf
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, USA; Lilly Diabetes Research Center, Indiana Biosciences Research Institute, Indianapolis, IN, USA
| | - Betty Lorentz
- Lilly Diabetes Research Center, Indiana Biosciences Research Institute, Indianapolis, IN, USA
| | - Connor A Mahler
- Lilly Diabetes Research Center, Indiana Biosciences Research Institute, Indianapolis, IN, USA
| | - Olivia Lazzaro
- Lilly Diabetes Research Center, Indiana Biosciences Research Institute, Indianapolis, IN, USA
| | - Britany App
- Lilly Diabetes Research Center, Indiana Biosciences Research Institute, Indianapolis, IN, USA
| | - Shudi Zhou
- Department of Medical Neuroscience, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Yura Yamamoto
- Lilly Diabetes Research Center, Indiana Biosciences Research Institute, Indianapolis, IN, USA
| | - Mya Suber
- Lilly Diabetes Research Center, Indiana Biosciences Research Institute, Indianapolis, IN, USA
| | - Jamie C Wann
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Hyun Cheol Roh
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Patrick L Sheets
- Department of Medical Neuroscience, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Travis S Johnson
- Lilly Diabetes Research Center, Indiana Biosciences Research Institute, Indianapolis, IN, USA; Department of Biostatistics and Health Data Science, Indiana University School of Medicine, Indianapolis, IN, USA; Melvin and Bren Simon Comprehensive Cancer Centre, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Jonathan N Flak
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, USA; Lilly Diabetes Research Center, Indiana Biosciences Research Institute, Indianapolis, IN, USA.
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Hashsham A, Kodur N, Su J, Tomlinson AJ, Yacawych WT, Flak JN, Lewis KT, Oles LR, Mori H, Bozadjieva-Kramer N, Turcu AF, MacDougald OA, Myers MG, Affinati AH. Control of Physiologic Glucose Homeostasis via the Hypothalamic Modulation of Gluconeogenic Substrate Availability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.20.594873. [PMID: 38826340 PMCID: PMC11142065 DOI: 10.1101/2024.05.20.594873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
The brain augments glucose production during fasting, but the mechanisms are poorly understood. Here, we show that Cckbr-expressing neurons in the ventromedial hypothalamic nucleus (VMNCckbr cells) prevent low blood glucose during fasting through sympathetic nervous system (SNS)-mediated augmentation of adipose tissue lipolysis and substrate release. Activating VMNCckbr neurons mobilized gluconeogenic substrates without altering glycogenolysis or gluconeogenic enzyme expression. Silencing these cells (CckbrTetTox animals) reduced fasting blood glucose, impaired lipolysis, and decreased circulating glycerol (but not other gluconeogenic substrates) despite normal insulin, counterregulatory hormones, liver glycogen, and liver gluconeogenic gene expression. Furthermore, β3-adrenergic adipose tissue stimulation in CckbrTetTox animals restored lipolysis and blood glucose. Hence, VMNCckbr neurons impact blood glucose not by controlling islet or liver physiology, but rather by mobilizing gluconeogenic substrates. These findings establish a central role for hypothalamic and SNS signaling during normal glucose homeostasis and highlight the importance of gluconeogenic substrate mobilization during physiologic fasting.
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Affiliation(s)
- Abdullah Hashsham
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Nandan Kodur
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Jiaao Su
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | | | - Warren T. Yacawych
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Jon N. Flak
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Kenneth T. Lewis
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Lily R. Oles
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Hiroyuki Mori
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Nadejda Bozadjieva-Kramer
- Veterans Affairs Ann Arbor Healthcare System; Research Service, Ann Arbor, MI
- University of Michigan, Department of Surgery; Ann Arbor, MI
| | - Adina F. Turcu
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Ormond A. MacDougald
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Martin G. Myers
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
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Jones AA, Arble DM. In light of breathing: environmental light is an important modulator of breathing with clinical implications. Front Neurosci 2023; 17:1217799. [PMID: 37521684 PMCID: PMC10373889 DOI: 10.3389/fnins.2023.1217799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 06/27/2023] [Indexed: 08/01/2023] Open
Abstract
In vertebrate animals, the automatic, rhythmic pattern of breathing is a highly regulated process that can be modulated by various behavioral and physiological factors such as metabolism, sleep-wake state, activity level, and endocrine signaling. Environmental light influences many of these modulating factors both indirectly by organizing daily and seasonal rhythms of behavior and directly through acute changes in neural signaling. While several observations from rodent and human studies suggest that environmental light affects breathing, few have systematically evaluated the underlying mechanisms and clinical relevance of environmental light on the regulation of respiratory behavior. Here, we provide new evidence and discuss the potential neurobiological mechanisms by which light modulates breathing. We conclude that environmental light should be considered, from bench to bedside, as a clinically relevant modulator of respiratory health and disease.
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Liu J, Lai F, Hou Y, Zheng R. Leptin signaling and leptin resistance. MEDICAL REVIEW (BERLIN, GERMANY) 2022; 2:363-384. [PMID: 37724323 PMCID: PMC10388810 DOI: 10.1515/mr-2022-0017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 07/12/2022] [Indexed: 09/20/2023]
Abstract
With the prevalence of obesity and associated comorbidities, studies aimed at revealing mechanisms that regulate energy homeostasis have gained increasing interest. In 1994, the cloning of leptin was a milestone in metabolic research. As an adipocytokine, leptin governs food intake and energy homeostasis through leptin receptors (LepR) in the brain. The failure of increased leptin levels to suppress feeding and elevate energy expenditure is referred to as leptin resistance, which encompasses complex pathophysiological processes. Within the brain, LepR-expressing neurons are distributed in hypothalamus and other brain areas, and each population of the LepR-expressing neurons may mediate particular aspects of leptin effects. In LepR-expressing neurons, the binding of leptin to LepR initiates multiple signaling cascades including janus kinase (JAK)-signal transducers and activators of transcription (STAT) phosphatidylinositol 3-kinase (PI3K)-protein kinase B (AKT), extracellular regulated protein kinase (ERK), and AMP-activated protein kinase (AMPK) signaling, etc., mediating leptin actions. These findings place leptin at the intersection of metabolic and neuroendocrine regulations, and render leptin a key target for treating obesity and associated comorbidities. This review highlights the main discoveries that shaped the field of leptin for better understanding of the mechanism governing metabolic homeostasis, and guides the development of safe and effective interventions to treat obesity and associated diseases.
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Affiliation(s)
- Jiarui Liu
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Health Science Center, Peking University, Beijing, China
| | - Futing Lai
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Health Science Center, Peking University, Beijing, China
| | - Yujia Hou
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Health Science Center, Peking University, Beijing, China
| | - Ruimao Zheng
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Health Science Center, Peking University, Beijing, China
- Neuroscience Research Institute, Peking University, Beijing, China
- Key Laboratory for Neuroscience of Ministry of Education, Peking University, Beijing, China
- Key Laboratory for Neuroscience of National Health Commission, Peking University, Beijing 100191, China
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5
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Cheng W, Ndoka E, Maung JN, Pan W, Rupp AC, Rhodes CJ, Olson DP, Myers MG. NTS Prlh overcomes orexigenic stimuli and ameliorates dietary and genetic forms of obesity. Nat Commun 2021; 12:5175. [PMID: 34462445 PMCID: PMC8405610 DOI: 10.1038/s41467-021-25525-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 08/11/2021] [Indexed: 11/09/2022] Open
Abstract
Calcitonin receptor (Calcr)-expressing neurons of the nucleus tractus solitarius (NTS; CalcrNTS cells) contribute to the long-term control of food intake and body weight. Here, we show that Prlh-expressing NTS (PrlhNTS) neurons represent a subset of CalcrNTS cells and that Prlh expression in these cells restrains body weight gain in the face of high fat diet challenge in mice. To understand the relationship of PrlhNTS cells to hypothalamic feeding circuits, we determined the ability of PrlhNTS-mediated signals to overcome enforced activation of AgRP neurons. We found that PrlhNTS neuron activation and Prlh overexpression in PrlhNTS cells abrogates AgRP neuron-driven hyperphagia and ameliorates the obesity of mice deficient in melanocortin signaling or leptin. Thus, enhancing Prlh-mediated neurotransmission from the NTS dampens hypothalamically-driven hyperphagia and obesity, demonstrating that NTS-mediated signals can override the effects of orexigenic hypothalamic signals on long-term energy balance. Calcitonin receptor-expressing neurons of the nucleus tractus solitarius contribute to long-term control of food intake and body weight. The authors show that a subset of these cells expresses Prlh and that enhancing Prlh-mediated neurotransmission from the NTS dampens hypothalamically-driven hyperphagia and obesity in mice.
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Affiliation(s)
- Wenwen Cheng
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA.
| | - Ermelinda Ndoka
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Jessica N Maung
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Warren Pan
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Alan C Rupp
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Christopher J Rhodes
- Research and Early Development, Cardiovascular, Renal, and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - David P Olson
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.,Division of Endocrinology, Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Martin G Myers
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA. .,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.
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6
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Projections from the lateral parabrachial nucleus to the lateral and ventral lateral periaqueductal gray subregions mediate the itching sensation. Pain 2021; 162:1848-1863. [PMID: 33449512 DOI: 10.1097/j.pain.0000000000002193] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/30/2020] [Indexed: 11/25/2022]
Abstract
ABSTRACT Lateral and ventral lateral subregions of the periaqueductal gray (l/vlPAG) have been proved to be pivotal components in descending circuitry of itch processing, and their effects are related to the subclassification of neurons that were meditated. In this study, lateral parabrachial nucleus (LPB), one of the most crucial relay stations in the ascending pathway, was taken as the input nucleus to examine the modulatory effect of l/vlPAG neurons that received LPB projections. Anatomical tracing, chemogenetic, optogenetic, and local pharmacological approaches were used to investigate the participation of the LPB-l/vlPAG pathway in itch and pain sensation in mice. First, morphological evidence for projections from vesicular glutamate transporter-2-containing neurons in the LPB to l/vlPAG involved in itch transmission has been provided. Furthermore, chemogenetic and optogenetic activation of the LPB-l/vlPAG pathway resulted in both antipruritic effect and analgesic effect, whereas pharmacogenetic inhibition strengthened nociceptive perception without affecting spontaneous scratching behavior. Finally, in vivo pharmacology was combined with optogenetics which revealed that AMPA receptor-expressing neurons in l/vlPAG might play a more essential role in pathway modulation. These findings provide a novel insight about the connections between 2 prominent transmit nuclei, LPB and l/vlPAG, in both pruriceptive and nociceptive sensations and deepen the understanding of l/vlPAG modulatory roles in itch sensation by chosen LPB as source of ascending efferent projections.
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7
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Bozadjieva-Kramer N, Ross RA, Johnson DQ, Fenselau H, Haggerty DL, Atwood B, Lowell B, Flak JN. The Role of Mediobasal Hypothalamic PACAP in the Control of Body Weight and Metabolism. Endocrinology 2021; 162:6103920. [PMID: 33460433 PMCID: PMC7875177 DOI: 10.1210/endocr/bqab012] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Indexed: 12/26/2022]
Abstract
Body energy homeostasis results from balancing energy intake and energy expenditure. Central nervous system administration of pituitary adenylate cyclase activating polypeptide (PACAP) dramatically alters metabolic function, but the physiologic mechanism of this neuropeptide remains poorly defined. PACAP is expressed in the mediobasal hypothalamus (MBH), a brain area essential for energy balance. Ventromedial hypothalamic nucleus (VMN) neurons contain, by far, the largest and most dense population of PACAP in the medial hypothalamus. This region is involved in coordinating the sympathetic nervous system in response to metabolic cues in order to re-establish energy homeostasis. Additionally, the metabolic cue of leptin signaling in the VMN regulates PACAP expression. We hypothesized that PACAP may play a role in the various effector systems of energy homeostasis, and tested its role by using VMN-directed, but MBH encompassing, adeno-associated virus (AAVCre) injections to ablate Adcyap1 (gene coding for PACAP) in mice (Adcyap1MBHKO mice). Adcyap1MBHKO mice rapidly gained body weight and adiposity, becoming hyperinsulinemic and hyperglycemic. Adcyap1MBHKO mice exhibited decreased oxygen consumption (VO2), without changes in activity. These effects appear to be due at least in part to brown adipose tissue (BAT) dysfunction, and we show that PACAP-expressing cells in the MBH can stimulate BAT thermogenesis. While we observed disruption of glucose clearance during hyperinsulinemic/euglycemic clamp studies in obese Adcyap1MBHKO mice, these parameters were normal prior to the onset of obesity. Thus, MBH PACAP plays important roles in the regulation of metabolic rate and energy balance through multiple effector systems on multiple time scales, which highlight the diverse set of functions for PACAP in overall energy homeostasis.
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Affiliation(s)
| | - Rachel A Ross
- Albert Einstein College of Medicine, Bronx, NY, USA
- Beth Israel Deaconess Medical Center, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - David Q Johnson
- Indiana Biosciences Research Institute, Diabetes Research Center, Indianapolis, IN, USA
| | - Henning Fenselau
- Beth Israel Deaconess Medical Center, Boston, MA, USA
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Cologne, Germany
- Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - David L Haggerty
- Indiana University School of Medicine, Pharmacology and Toxicology, Indianapolis, IN, USA
| | - Brady Atwood
- Indiana University School of Medicine, Pharmacology and Toxicology, Indianapolis, IN, USA
| | - Bradford Lowell
- Beth Israel Deaconess Medical Center, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Jonathan N Flak
- Indiana Biosciences Research Institute, Diabetes Research Center, Indianapolis, IN, USA
- Indiana University School of Medicine, Pharmacology and Toxicology, Indianapolis, IN, USA
- Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan, Ann Arbor, MI, USA
- Correspondence: Jonathan N. Flak, PhD, Indiana Biosciences Research Institute, 1345 W. 16th Street, Indianapolis, IN 46022, USA.
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8
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Pereira S, Cline DL, Glavas MM, Covey SD, Kieffer TJ. Tissue-Specific Effects of Leptin on Glucose and Lipid Metabolism. Endocr Rev 2021; 42:1-28. [PMID: 33150398 PMCID: PMC7846142 DOI: 10.1210/endrev/bnaa027] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Indexed: 12/18/2022]
Abstract
The discovery of leptin was intrinsically associated with its ability to regulate body weight. However, the effects of leptin are more far-reaching and include profound glucose-lowering and anti-lipogenic effects, independent of leptin's regulation of body weight. Regulation of glucose metabolism by leptin is mediated both centrally and via peripheral tissues and is influenced by the activation status of insulin signaling pathways. Ectopic fat accumulation is diminished by both central and peripheral leptin, an effect that is beneficial in obesity-associated disorders. The magnitude of leptin action depends upon the tissue, sex, and context being examined. Peripheral tissues that are of particular relevance include the endocrine pancreas, liver, skeletal muscle, adipose tissues, immune cells, and the cardiovascular system. As a result of its potent metabolic activity, leptin is used to control hyperglycemia in patients with lipodystrophy and is being explored as an adjunct to insulin in patients with type 1 diabetes. To fully understand the role of leptin in physiology and to maximize its therapeutic potential, the mechanisms of leptin action in these tissues needs to be further explored.
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Affiliation(s)
- Sandra Pereira
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Daemon L Cline
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Maria M Glavas
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Scott D Covey
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Timothy J Kieffer
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada.,Department of Surgery, University of British Columbia, Vancouver, Canada.,School of Biomedical Engineering, University of British Columbia, Vancouver, Canada
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9
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Zhu C, Jiang Z, Xu Y, Cai ZL, Jiang Q, Xu Y, Xue M, Arenkiel BR, Wu Q, Shu G, Tong Q. Profound and redundant functions of arcuate neurons in obesity development. Nat Metab 2020; 2:763-774. [PMID: 32719538 PMCID: PMC7687864 DOI: 10.1038/s42255-020-0229-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 05/28/2020] [Indexed: 02/06/2023]
Abstract
The current obesity epidemic faces a lack of mechanistic insights. It is known that the acute activity changes of a growing number of brain neurons rapidly alter feeding behaviour; however, how these changes translate to obesity development and the fundamental mechanism underlying brain neurons in controlling body weight remain elusive. Here, we show that chronic activation of hypothalamic arcuate GABAergic (GABA+), agouti-related protein (AgRP) neurons or arcuate non-AgRP GABA+ neurons leads to obesity, which is similar to the obese phenotype observed in ob/ob mice. Conversely, chronic inhibition of arcuate GABA+, but not AgRP, neurons reduces ageing-related weight gain and corrects ob/ob obesity. These results demonstrate that the modulation of Arc GABA+ neuron activity is a fundamental mechanism of body-weight regulation, and that arcuate GABA+ neurons are the major mediator of leptin action, with a profound and redundant role in obesity development.
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Affiliation(s)
- Canjun Zhu
- Brown Foundation Institute of Molecular Medicine of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, College of Animal Science, South China Agricultural University, Guangdong, China
| | - Zhiying Jiang
- Brown Foundation Institute of Molecular Medicine of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Yuanzhong Xu
- Brown Foundation Institute of Molecular Medicine of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Zhao-Lin Cai
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA
| | - Qingyan Jiang
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, College of Animal Science, South China Agricultural University, Guangdong, China
| | - Yong Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Mingshan Xue
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA
- Department of Molecular and Human Genetics and Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Benjamin R Arenkiel
- Department of Molecular and Human Genetics and Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Qi Wu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Gang Shu
- Guangdong Province Key Laboratory of Animal Nutritional Regulation, College of Animal Science, South China Agricultural University, Guangdong, China.
| | - Qingchun Tong
- Brown Foundation Institute of Molecular Medicine of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA.
- Department of Neurobiology and Anatomy of McGovern Medical School and Program in Neuroscience of MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, TX, USA.
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10
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Gauda EB, Conde S, Bassi M, Zoccal DB, Almeida Colombari DS, Colombari E, Despotovic N. Leptin: Master Regulator of Biological Functions that Affects Breathing. Compr Physiol 2020; 10:1047-1083. [PMID: 32941688 DOI: 10.1002/cphy.c190031] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Obesity is a global epidemic in developed countries accounting for many of the metabolic and cardiorespiratory morbidities that occur in adults. These morbidities include type 2 diabetes, sleep-disordered breathing (SDB), obstructive sleep apnea, chronic intermittent hypoxia, and hypertension. Leptin, produced by adipocytes, is a master regulator of metabolism and of many other biological functions including central and peripheral circuits that control breathing. By binding to receptors on cells and neurons in the brainstem, hypothalamus, and carotid body, leptin links energy and metabolism to breathing. In this comprehensive article, we review the central and peripheral locations of leptin's actions that affect cardiorespiratory responses during health and disease, with a particular focus on obesity, SDB, and its effects during early development. Obesity-induced hyperleptinemia is associated with centrally mediated hypoventilation with decrease CO2 sensitivity. On the other hand, hyperleptinemia augments peripheral chemoreflexes to hypoxia and induces sympathoexcitation. Thus, "leptin resistance" in obesity is relative. We delineate the circuits responsible for these divergent effects, including signaling pathways. We review the unique effects of leptin during development on organogenesis, feeding behavior, and cardiorespiratory responses, and how undernutrition and overnutrition during critical periods of development can lead to cardiorespiratory comorbidities in adulthood. We conclude with suggestions for future directions to improve our understanding of leptin dysregulation and associated clinical diseases and possible therapeutic targets. Lastly, we briefly discuss the yin and the yang, specifically the contribution of relative adiponectin deficiency in adults with hyperleptinemia to the development of metabolic and cardiovascular disease. © 2020 American Physiological Society. Compr Physiol 10:1047-1083, 2020.
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Affiliation(s)
- Estelle B Gauda
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Silvia Conde
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Lisboa, Portugal
| | - Mirian Bassi
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Daniel B Zoccal
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Debora Simoes Almeida Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Nikola Despotovic
- Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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11
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Flak JN, Goforth PB, Dell’Orco J, Sabatini PV, Li C, Bozadjieva N, Sorensen M, Valenta A, Rupp A, Affinati AH, Cras-Méneur C, Ansari A, Sacksner J, Kodur N, Sandoval DA, Kennedy RT, Olson DP, Myers MG. Ventromedial hypothalamic nucleus neuronal subset regulates blood glucose independently of insulin. J Clin Invest 2020; 130:2943-2952. [PMID: 32134398 PMCID: PMC7260001 DOI: 10.1172/jci134135] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 02/20/2020] [Indexed: 12/14/2022] Open
Abstract
To identify neurons that specifically increase blood glucose from among the diversely functioning cell types in the ventromedial hypothalamic nucleus (VMN), we studied the cholecystokinin receptor B-expressing (CCKBR-expressing) VMN targets of glucose-elevating parabrachial nucleus neurons. Activation of these VMNCCKBR neurons increased blood glucose. Furthermore, although silencing the broader VMN decreased energy expenditure and promoted weight gain without altering blood glucose levels, silencing VMNCCKBR neurons decreased hIepatic glucose production, insulin-independently decreasing blood glucose without altering energy balance. Silencing VMNCCKBR neurons also impaired the counterregulatory response to insulin-induced hypoglycemia and glucoprivation and replicated hypoglycemia-associated autonomic failure. Hence, VMNCCKBR cells represent a specialized subset of VMN cells that function to elevate glucose. These cells not only mediate the allostatic response to hypoglycemia but also modulate the homeostatic setpoint for blood glucose in an insulin-independent manner, consistent with a role for the brain in the insulin-independent control of glucose homeostasis.
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Affiliation(s)
| | - Paulette B. Goforth
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan, USA
| | | | | | - Chien Li
- Novo Nordisk, Seattle, Washington, USA
| | | | | | | | | | | | | | | | | | | | | | | | - David P. Olson
- Division of Endocrinology, Department of Pediatrics, University of Michigan, Ann Arbor, Michigan, USA
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12
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Abstract
Obstructive sleep apnea (OSA), characterized by recurrent episodes of apnea during sleep and daytime sleepiness, seriously affects human health and may lead to systemic organ dysfunction. The pathogenesis of OSA is complex and still uncertain, but multiple surveys have shown that obesity is an important factor, and the incidence of OSA in people with obesity is as high as 30%. Adipokines are a group of proteins secreted from adipocytes, which are dysregulated in obesity and may contribute to OSA. Here, we review the most important and representative research results regarding the correlation between obesity-related adipokines including leptin, adiponectin, omentin-1, chemerin, and resistin and OSA in the past 5 years, provide an overview of these key adipokines, and analyze possible intrinsic mechanisms and influencing factors. The existing research shows that OSA is associated with an increase in the serum levels of leptin, chemerin, and resistin and a decrease in the levels of adiponectin and omentin-1; the findings presented here can be used to monitor the development of OSA and obesity, prevent future comorbidities, and identify risk factors for cardiovascular and other diseases, while different adipokines can be linked to OSA through different pathways such as insulin resistance, intermittent hypoxia, and inflammation, among others. We hope our review leads to a deeper and more comprehensive understanding of OSA based on the relevant literature, which will also provide directions for future clinical research.
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Affiliation(s)
- Xiongye Xu
- The First Clinical Medical College of Nanchang University, Nanchang, People's Republic of China
| | - Jixiong Xu
- The First Clinical Medical College of Nanchang University, Nanchang, People's Republic of China
- Department of Endocrinology and Metabolism, First Affiliated Hospital of Nanchang University, Nanchang, People's Republic of China
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13
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Cheng W, Gonzalez I, Pan W, Tsang AH, Adams J, Ndoka E, Gordian D, Khoury B, Roelofs K, Evers SS, MacKinnon A, Wu S, Frikke-Schmidt H, Flak JN, Trevaskis JL, Rhodes CJ, Fukada SI, Seeley RJ, Sandoval DA, Olson DP, Blouet C, Myers MG. Calcitonin Receptor Neurons in the Mouse Nucleus Tractus Solitarius Control Energy Balance via the Non-aversive Suppression of Feeding. Cell Metab 2020; 31:301-312.e5. [PMID: 31955990 PMCID: PMC7104375 DOI: 10.1016/j.cmet.2019.12.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 08/29/2019] [Accepted: 12/20/2019] [Indexed: 02/02/2023]
Abstract
To understand hindbrain pathways involved in the control of food intake, we examined roles for calcitonin receptor (CALCR)-containing neurons in the NTS. Ablation of NTS Calcr abrogated the long-term suppression of food intake, but not aversive responses, by CALCR agonists. Similarly, activating CalcrNTS neurons decreased food intake and body weight but (unlike neighboring CckNTS cells) failed to promote aversion, revealing that CalcrNTS neurons mediate a non-aversive suppression of food intake. While both CalcrNTS and CckNTS neurons decreased feeding via projections to the PBN, CckNTS cells activated aversive CGRPPBN cells while CalcrNTS cells activated distinct non-CGRP PBN cells. Hence, CalcrNTS cells suppress feeding via non-aversive, non-CGRP PBN targets. Additionally, silencing CalcrNTS cells blunted food intake suppression by gut peptides and nutrients, increasing food intake and promoting obesity. Hence, CalcrNTS neurons define a hindbrain system that participates in physiological energy balance and suppresses food intake without activating aversive systems.
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Affiliation(s)
- Wenwen Cheng
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48105, USA
| | - Ian Gonzalez
- Division of Endocrinology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI 48105, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48105, USA
| | - Warren Pan
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48105, USA; Graduate Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48105, USA
| | - Anthony H Tsang
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Jessica Adams
- Division of Endocrinology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI 48105, USA
| | - Ermelinda Ndoka
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48105, USA
| | - Desiree Gordian
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48105, USA
| | - Basma Khoury
- Department of Surgery, University of Michigan, Ann Arbor, MI 48105, USA
| | - Karen Roelofs
- Department of Surgery, University of Michigan, Ann Arbor, MI 48105, USA
| | - Simon S Evers
- Department of Surgery, University of Michigan, Ann Arbor, MI 48105, USA
| | - Andrew MacKinnon
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48105, USA
| | - Shuangcheng Wu
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48105, USA
| | | | - Jonathan N Flak
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48105, USA
| | - James L Trevaskis
- Cardiovascular, Renal and Metabolic Diseases, AstraZenica LLC, Gaithersburg, MD 20878, USA
| | - Christopher J Rhodes
- Cardiovascular, Renal and Metabolic Diseases, AstraZenica LLC, Gaithersburg, MD 20878, USA
| | - So-Ichiro Fukada
- Laboratory of Molecular and Cellular Physiology, Osaka University, Osaka 565-0871, Japan
| | - Randy J Seeley
- Department of Surgery, University of Michigan, Ann Arbor, MI 48105, USA
| | - Darleen A Sandoval
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48105, USA; Department of Surgery, University of Michigan, Ann Arbor, MI 48105, USA
| | - David P Olson
- Division of Endocrinology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI 48105, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48105, USA
| | - Clemence Blouet
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, UK.
| | - Martin G Myers
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48105, USA; Division of Endocrinology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI 48105, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48105, USA; Graduate Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48105, USA.
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14
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Wang L, Vanacker C, Burger LL, Barnes T, Shah YM, Myers MG, Moenter SM. Genetic dissection of the different roles of hypothalamic kisspeptin neurons in regulating female reproduction. eLife 2019; 8:e43999. [PMID: 30946012 PMCID: PMC6491090 DOI: 10.7554/elife.43999] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Accepted: 04/02/2019] [Indexed: 12/12/2022] Open
Abstract
The brain regulates fertility through gonadotropin-releasing hormone (GnRH) neurons. Estradiol induces negative feedback on pulsatile GnRH/luteinizing hormone (LH) release and positive feedback generating preovulatory GnRH/LH surges. Negative and positive feedbacks are postulated to be mediated by kisspeptin neurons in arcuate and anteroventral periventricular (AVPV) nuclei, respectively. Kisspeptin-specific ERα knockout mice exhibit disrupted LH pulses and surges. This knockout approach is neither location-specific nor temporally controlled. We utilized CRISPR-Cas9 to disrupt ERα in adulthood. Mice with ERα disruption in AVPV kisspeptin neurons have typical reproductive cycles but blunted LH surges, associated with decreased excitability of these neurons. Mice with ERα knocked down in arcuate kisspeptin neurons showed disrupted cyclicity, associated with increased glutamatergic transmission to these neurons. These observations suggest that activational effects of estradiol regulate surge generation and maintain cyclicity through AVPV and arcuate kisspeptin neurons, respectively, independent from its role in the development of hypothalamic kisspeptin neurons or puberty onset.
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Affiliation(s)
- Luhong Wang
- Department of Molecular and Integrative PhysiologyUniversity of MichiganAnn ArborUnited States
| | - Charlotte Vanacker
- Department of Molecular and Integrative PhysiologyUniversity of MichiganAnn ArborUnited States
| | - Laura L Burger
- Department of Molecular and Integrative PhysiologyUniversity of MichiganAnn ArborUnited States
| | - Tammy Barnes
- Department of Internal MedicineUniversity of MichiganAnn ArborUnited States
| | - Yatrik M Shah
- Department of Molecular and Integrative PhysiologyUniversity of MichiganAnn ArborUnited States
| | - Martin G Myers
- Department of Molecular and Integrative PhysiologyUniversity of MichiganAnn ArborUnited States
- Department of Internal MedicineUniversity of MichiganAnn ArborUnited States
| | - Suzanne M Moenter
- Department of Internal MedicineUniversity of MichiganAnn ArborUnited States
- Department of Obstetrics & GynecologyUniversity of MichiganAnn ArborUnited States
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15
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Arble DM, Schwartz AR, Polotsky VY, Sandoval DA, Seeley RJ. Vertical sleeve gastrectomy improves ventilatory drive through a leptin-dependent mechanism. JCI Insight 2019; 4:124469. [PMID: 30626748 DOI: 10.1172/jci.insight.124469] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 11/29/2018] [Indexed: 12/18/2022] Open
Abstract
Obesity hypoventilation syndrome (OHS) is a serious disorder characterized by daytime hypercapnia, disordered breathing, and a reduction in chemosensitivity. Vertical sleeve gastrectomy (VSG), a bariatric surgical procedure resulting in weight loss and weight-independent improvements in glucose metabolism, has been observed to substantially improve sleep-disordered breathing. However, it is unclear if the ventilatory effects of VSG are secondary to weight loss or the marked change in metabolic physiology. Using preclinical mouse models, we found that VSG leads to an improvement in the hypercapnic ventilatory response (HCVR) and reductions in circulating leptin levels independent of reductions in body mass, fat mass, and caloric intake. In the absence of leptin, VSG continues to improve body mass, fat mass, and glucose tolerance in ob/ob mice but no longer affects HCVR. However, the HCVR of ob/ob mice can be returned to wild-type levels with leptin treatment. These data demonstrate that VSG improves chemosensitivity and ventilatory drive via a leptin-dependent mechanism. Clinically, these data downgrade the relative contribution of physical, mechanical load in the pathogenesis of OHS, and instead point to physiological components of obesity, including alterations in leptin signaling, as key drivers in OHS.
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Affiliation(s)
- Deanna M Arble
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin, USA.,Department of Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Alan R Schwartz
- Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Vsevolod Y Polotsky
- Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | | | - Randy J Seeley
- Department of Surgery, University of Michigan, Ann Arbor, Michigan, USA
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16
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Faber CL, Matsen ME, Velasco KR, Damian V, Phan BA, Adam D, Therattil A, Schwartz MW, Morton GJ. Distinct Neuronal Projections From the Hypothalamic Ventromedial Nucleus Mediate Glycemic and Behavioral Effects. Diabetes 2018; 67:2518-2529. [PMID: 30257978 PMCID: PMC6245222 DOI: 10.2337/db18-0380] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 09/17/2018] [Indexed: 01/03/2023]
Abstract
The hypothalamic ventromedial nucleus (VMN) is implicated both in autonomic control of blood glucose and in behaviors including fear and aggression, but whether these divergent effects involve the same or distinct neuronal subsets and their projections is unknown. To address this question, we used an optogenetic approach to selectively activate the subset of VMN neurons that express neuronal nitric oxide synthase 1 (VMNNOS1 neurons) implicated in glucose counterregulation. We found that photoactivation of these neurons elicits 1) robust hyperglycemia achieved by activation of counterregulatory responses usually reserved for the physiological response to hypoglycemia and 2) defensive immobility behavior. Moreover, we show that the glucagon, but not corticosterone, response to insulin-induced hypoglycemia is blunted by photoinhibition of the same neurons. To investigate the neurocircuitry by which VMNNOS1 neurons mediate these effects, and to determine whether these diverse effects are dissociable from one another, we activated downstream VMNNOS1 projections in either the anterior bed nucleus of the stria terminalis (aBNST) or the periaqueductal gray (PAG). Whereas glycemic responses are fully recapitulated by activation of VMNNOS1 projections to the aBNST, freezing immobility occurred only upon activation of VMNNOS1 terminals in the PAG. These findings support previous evidence of a VMN→aBNST neurocircuit involved in glucose counterregulation and demonstrate that activation of VMNNOS1 neuronal projections supplying the PAG robustly elicits defensive behaviors.
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Affiliation(s)
- Chelsea L Faber
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Miles E Matsen
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Kevin R Velasco
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Vincent Damian
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Bao Anh Phan
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Daniel Adam
- School of Medicine, Creighton University, Omaha, NE
| | | | - Michael W Schwartz
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Gregory J Morton
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
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17
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Alvarsson A, Stanley SA. Remote control of glucose-sensing neurons to analyze glucose metabolism. Am J Physiol Endocrinol Metab 2018; 315:E327-E339. [PMID: 29812985 PMCID: PMC6171010 DOI: 10.1152/ajpendo.00469.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 04/25/2018] [Accepted: 05/23/2018] [Indexed: 12/13/2022]
Abstract
The central nervous system relies on a continual supply of glucose, and must be able to detect glucose levels and regulate peripheral organ functions to ensure that its energy requirements are met. Specialized glucose-sensing neurons, first described half a century ago, use glucose as a signal and modulate their firing rates as glucose levels change. Glucose-excited neurons are activated by increasing glucose concentrations, while glucose-inhibited neurons increase their firing rate as glucose concentrations fall and decrease their firing rate as glucose concentrations rise. Glucose-sensing neurons are present in multiple brain regions and are highly expressed in hypothalamic regions, where they are involved in functions related to glucose homeostasis. However, the roles of glucose-sensing neurons in healthy and disease states remain poorly understood. Technologies that can rapidly and reversibly activate or inhibit defined neural populations provide invaluable tools to investigate how specific neural populations regulate metabolism and other physiological roles. Optogenetics has high temporal and spatial resolutions, requires implants for neural stimulation, and is suitable for modulating local neural populations. Chemogenetics, which requires injection of a synthetic ligand, can target both local and widespread populations. Radio- and magnetogenetics offer rapid neural activation in localized or widespread neural populations without the need for implants or injections. These tools will allow us to better understand glucose-sensing neurons and their metabolism-regulating circuits.
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Affiliation(s)
- Alexandra Alvarsson
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai , New York, New York
| | - Sarah A Stanley
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai , New York, New York
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai , New York, New York
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18
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Framnes SN, Arble DM. The Bidirectional Relationship Between Obstructive Sleep Apnea and Metabolic Disease. Front Endocrinol (Lausanne) 2018; 9:440. [PMID: 30127766 PMCID: PMC6087747 DOI: 10.3389/fendo.2018.00440] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 07/17/2018] [Indexed: 12/22/2022] Open
Abstract
Obstructive sleep apnea (OSA) is a common sleep disorder, effecting 17% of the total population and 40-70% of the obese population (1, 2). Multiple studies have identified OSA as a critical risk factor for the development of obesity, diabetes, and cardiovascular diseases (3-5). Moreover, emerging evidence indicates that metabolic disorders can exacerbate OSA, creating a bidirectional relationship between OSA and metabolic physiology. In this review, we explore the relationship between glycemic control, insulin, and leptin as both contributing factors and products of OSA. We conclude that while insulin and leptin action may contribute to the development of OSA, further research is required to determine the mechanistic actions and relative contributions independent of body weight. In addition to increasing our understanding of the etiology, further research into the physiological mechanisms underlying OSA can lead to the development of improved treatment options for individuals with OSA.
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Affiliation(s)
| | - Deanna M. Arble
- Department of Biological Sciences, Marquette University, Milwaukee, WI, United States
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19
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Palmiter RD. The Parabrachial Nucleus: CGRP Neurons Function as a General Alarm. Trends Neurosci 2018; 41:280-293. [PMID: 29703377 PMCID: PMC5929477 DOI: 10.1016/j.tins.2018.03.007] [Citation(s) in RCA: 244] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 02/17/2018] [Accepted: 03/07/2018] [Indexed: 12/24/2022]
Abstract
The parabrachial nucleus (PBN), which is located in the pons and is dissected by one of the major cerebellar output tracks, is known to relay sensory information (visceral malaise, taste, temperature, pain, itch) to forebrain structures including the thalamus, hypothalamus, and extended amygdala. The availability of mouse lines expressing Cre recombinase selectively in subsets of PBN neurons and viruses for Cre-dependent gene expression is beginning to reveal the connectivity and functions of PBN component neurons. This review focuses on PBN neurons expressing calcitonin gene-related peptide (CGRPPBN) that play a major role in regulating appetite and transmitting real or potential threat signals to the extended amygdala. The functions of other specific PBN neuronal populations are also discussed. This review aims to encourage investigation of the numerous unanswered questions that are becoming accessible.
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Affiliation(s)
- Richard D Palmiter
- Howard Hughes Medical Institute, and Departments of Biochemistry and Genome Sciences, University of Washington, Seattle, WA 98195, USA.
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20
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Meek TH, Matsen ME, Faber CL, Samstag CL, Damian V, Nguyen HT, Scarlett JM, Flak JN, Myers MG, Morton GJ. In Uncontrolled Diabetes, Hyperglucagonemia and Ketosis Result From Deficient Leptin Action in the Parabrachial Nucleus. Endocrinology 2018; 159:1585-1594. [PMID: 29438473 PMCID: PMC5939636 DOI: 10.1210/en.2017-03199] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 01/25/2018] [Indexed: 12/17/2022]
Abstract
Growing evidence implicates neurons that project from the lateral parabrachial nucleus (LPBN) to the hypothalamic ventromedial nucleus (VMN) in a neurocircuit that drives counterregulatory responses to hypoglycemia, including increased glucagon secretion. Among LPBN neurons in this circuit is a subset that expresses cholecystokinin (LPBNCCK neurons) and is tonically inhibited by leptin. Because uncontrolled diabetes is associated with both leptin deficiency and hyperglucagonemia, and because intracerebroventricular (ICV) leptin administration reverses both hyperglycemia and hyperglucagonemia in this setting, we hypothesized that deficient leptin inhibition of LPBNCCK neurons drives activation of this LPBN→VMN circuit and thereby results in hyperglucagonemia. Here, we report that although bilateral microinjection of leptin into the LPBN does not ameliorate hyperglycemia in rats with streptozotocin-induced diabetes mellitus (STZ-DM), it does attenuate the associated hyperglucagonemia and ketosis. To determine if LPBN leptin signaling is required for the antidiabetic effect of ICV leptin in STZ-DM, we studied mice in which the leptin receptor was selectively deleted from LPBNCCK neurons. Our findings show that although leptin signaling in these neurons is not required for the potent antidiabetic effect of ICV leptin, it is required for leptin-mediated suppression of diabetic hyperglucagonemia. Taken together, these findings suggest that leptin-mediated effects in animals with uncontrolled diabetes occur through actions involving multiple brain areas, including the LPBN, where leptin acts specifically to inhibit glucagon secretion and associated ketosis.
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Affiliation(s)
- Thomas H Meek
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
| | - Miles E Matsen
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
| | - Chelsea L Faber
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
| | - Colby L Samstag
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
| | - Vincent Damian
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
| | - Hong T Nguyen
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
| | - Jarrad M Scarlett
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
| | - Jonathan N Flak
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Martin G Myers
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Gregory J Morton
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
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21
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Abstract
Obesity represents the single most important risk factor for early disability and death in developed societies, and the incidence of obesity remains at staggering levels. CNS systems that modulate energy intake and expenditure in response to changes in body energy stores serve to maintain constant body adiposity; the adipocyte-derived hormone leptin and its receptor (LEPR) represent crucial regulators of these systems. As in the case of insulin resistance, a variety of mechanisms (including feedback inhibition, inflammation, gliosis and endoplasmic reticulum stress) have been proposed to interfere with leptin action and impede the systems that control body energy homeostasis to promote or maintain obesity, although the relative importance and contribution of each of these remain unclear. However, LEPR signalling may be increased (rather than impaired) in common obesity, suggesting that any obesity-associated defects in leptin action must result from lesions somewhere other than the initial LEPR signal. It is also possible that increased LEPR signalling could mediate some of the obesity-associated changes in hypothalamic function.
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22
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Liu J, Yang X, Yu S, Zheng R. The Leptin Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1090:123-144. [PMID: 30390288 DOI: 10.1007/978-981-13-1286-1_7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Leptin plays a critical role in the regulation of energy balance and metabolic homeostasis. Impairment of leptin signaling is closely involved in the pathogenesis of obesity and metabolic diseases, including diabetes, cardiovascular disease, etc. Leptin initiates its intracellular signaling in the leptin-receptor-expressing neurons in the central nervous system to exert physiological function, thereby leading to a suppression of appetite, a reduction of food intake, a promotion of mitochondrial oxidation, an enhancement of thermogenesis, and a decrease in body weight. In this review, the studies on leptin neural and cellular pathways are summarized with an emphasis on the progress made during the last 10 years, for better understanding the molecular mechanism of obesity and other metabolic diseases.
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Affiliation(s)
- Jiarui Liu
- Department of Anatomy, Histology and Embryology, Health Science Center, Peking University, Beijing, China.,Neuroscience Research Institute, Peking University, Beijing, China.,Key Laboratory for Neuroscience of Ministry of Education, Peking University, Beijing, China.,Key Laboratory for Neuroscience of National Health Commission, Peking University, Beijing, China
| | - Xiaoning Yang
- Department of Anatomy, Histology and Embryology, Health Science Center, Peking University, Beijing, China
| | - Siwang Yu
- Department of Molecular and Cellular Pharmacology, Peking University School of Pharmaceutical Sciences, Beijing, China
| | - Ruimao Zheng
- Department of Anatomy, Histology and Embryology, Health Science Center, Peking University, Beijing, China. .,Neuroscience Research Institute, Peking University, Beijing, China. .,Key Laboratory for Neuroscience of Ministry of Education, Peking University, Beijing, China. .,Key Laboratory for Neuroscience of National Health Commission, Peking University, Beijing, China.
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23
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Differential contribution of POMC and AgRP neurons to the regulation of regional autonomic nerve activity by leptin. Mol Metab 2017; 8:1-12. [PMID: 29289646 PMCID: PMC5985226 DOI: 10.1016/j.molmet.2017.12.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 11/30/2017] [Accepted: 12/12/2017] [Indexed: 02/06/2023] Open
Abstract
Objectives The autonomic nervous system is critically involved in mediating the control by leptin of many physiological processes. Here, we examined the role of the leptin receptor (LepR) in proopiomelanocortin (POMC) and agouti-related peptide (AgRP) neurons in mediating the effects of leptin on regional sympathetic and parasympathetic nerve activity. Methods We analyzed how deletion of the LepR in POMC neurons (POMCCre/LepRfl/fl mice) or AgRP neurons (AgRPCre/LepRfl/fl mice) affects the ability of leptin to increase sympathetic and parasympathetic nerve activity. We also studied mice lacking the catalytic p110α or p110β subunits of phosphatidylinositol-3 kinase (PI3K) in POMC neurons. Results Leptin-evoked increase in sympathetic nerve activity subserving thermogenic brown adipose tissue was partially blunted in mice lacking the LepR in either POMC or AgRP neurons. On the other hand, loss of the LepR in AgRP, but not POMC, neurons interfered with leptin-induced sympathetic nerve activation to the inguinal fat depot. The increase in hepatic sympathetic traffic induced by leptin was also reduced in mice lacking the LepR in AgRP, but not POMC, neurons whereas LepR deletion in either AgRP or POMC neurons attenuated the hepatic parasympathetic nerve activation evoked by leptin. Interestingly, the renal, lumbar and splanchnic sympathetic nerve activation caused by leptin were significantly blunted in POMCCre/LepRfl/fl mice, but not in AgRPCre/LepRfl/fl mice. However, loss of the LepR in POMC or AgRP neurons did not interfere with the ability of leptin to increase sympathetic traffic to the adrenal gland. Furthermore, ablation of the p110α, but not the p110β, isoform of PI3K from POMC neurons eliminated the leptin-elicited renal sympathetic nerve activation. Finally, we show trans-synaptic retrograde tracing of both POMC and AgRP neurons from the kidneys. Conclusions POMC and AgRP neurons are differentially involved in mediating the effects of leptin on autonomic nerve activity subserving various tissues and organs. Both POMC and AgRP neurons contribute to leptin-elicited increase in BAT SNA and hepatic PSNA. AgRP neurons mediate leptin-evoked increase in SNA subserving WAT and liver. Leptin-induced increase in lumbar, splanchnic and renal SNA is mediated by POMC neurons. The p110α, but not p110β, subunit of PI3K in POMC neurons is required for the effect of leptin on renal SNA.
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