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Harno E, Gali Ramamoorthy T, Coll AP, White A. POMC: The Physiological Power of Hormone Processing. Physiol Rev 2019; 98:2381-2430. [PMID: 30156493 DOI: 10.1152/physrev.00024.2017] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Pro-opiomelanocortin (POMC) is the archetypal polypeptide precursor of hormones and neuropeptides. In this review, we examine the variability in the individual peptides produced in different tissues and the impact of the simultaneous presence of their precursors or fragments. We also discuss the problems inherent in accurately measuring which of the precursors and their derived peptides are present in biological samples. We address how not being able to measure all the combinations of precursors and fragments quantitatively has affected our understanding of the pathophysiology associated with POMC processing. To understand how different ratios of peptides arise, we describe the role of the pro-hormone convertases (PCs) and their tissue specificities and consider the cellular processing pathways which enable regulated secretion of different peptides that play crucial roles in integrating a range of vital physiological functions. In the pituitary, correct processing of POMC peptides is essential to maintain the hypothalamic-pituitary-adrenal axis, and this processing can be disrupted in POMC-expressing tumors. In hypothalamic neurons expressing POMC, abnormalities in processing critically impact on the regulation of appetite, energy homeostasis, and body composition. More work is needed to understand whether expression of the POMC gene in a tissue equates to release of bioactive peptides. We suggest that this comprehensive view of POMC processing, with a focus on gaining a better understanding of the combination of peptides produced and their relative bioactivity, is a necessity for all involved in studying this fascinating physiological regulatory phenomenon.
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Affiliation(s)
- Erika Harno
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
| | - Thanuja Gali Ramamoorthy
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
| | - Anthony P Coll
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
| | - Anne White
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
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Kirwan P, Kay RG, Brouwers B, Herranz-Pérez V, Jura M, Larraufie P, Jerber J, Pembroke J, Bartels T, White A, Gribble FM, Reimann F, Farooqi IS, O'Rahilly S, Merkle FT. Quantitative mass spectrometry for human melanocortin peptides in vitro and in vivo suggests prominent roles for β-MSH and desacetyl α-MSH in energy homeostasis. Mol Metab 2018; 17:82-97. [PMID: 30201275 PMCID: PMC6197775 DOI: 10.1016/j.molmet.2018.08.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/08/2018] [Accepted: 08/16/2018] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVE The lack of pro-opiomelanocortin (POMC)-derived melanocortin peptides results in hypoadrenalism and severe obesity in both humans and rodents that is treatable with synthetic melanocortins. However, there are significant differences in POMC processing between humans and rodents, and little is known about the relative physiological importance of POMC products in the human brain. The aim of this study was to determine which POMC-derived peptides are present in the human brain, to establish their relative concentrations, and to test if their production is dynamically regulated. METHODS We analysed both fresh post-mortem human hypothalamic tissue and hypothalamic neurons derived from human pluripotent stem cells (hPSCs) using liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine the sequence and quantify the production of hypothalamic neuropeptides, including those derived from POMC. RESULTS In both in vitro and in vivo hypothalamic cells, LC-MS/MS revealed the sequence of hundreds of neuropeptides as a resource for the field. Although the existence of β-melanocyte stimulating hormone (MSH) is controversial, we found that both this peptide and desacetyl α-MSH (d-α-MSH) were produced in considerable excess of acetylated α-MSH. In hPSC-derived hypothalamic neurons, these POMC derivatives were appropriately trafficked, secreted, and their production was significantly (P < 0.0001) increased in response to the hormone leptin. CONCLUSIONS Our findings challenge the assumed pre-eminence of α-MSH and suggest that in humans, d-α-MSH and β-MSH are likely to be the predominant physiological products acting on melanocortin receptors.
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Affiliation(s)
- Peter Kirwan
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK; The Anne McLaren Laboratory for Regenerative Medicine, Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, CB2 0SZ, UK
| | - Richard G Kay
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Bas Brouwers
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK; The Anne McLaren Laboratory for Regenerative Medicine, Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, CB2 0SZ, UK
| | - Vicente Herranz-Pérez
- Laboratory of Comparative Neurobiology, Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, CIBERNED, 46980 Valencia, Spain; Predepartamental Unit of Medicine, Faculty of Health Sciences, Universitat Jaume I, 12071 Castelló de la Plana, Spain
| | - Magdalena Jura
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK; The Anne McLaren Laboratory for Regenerative Medicine, Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, CB2 0SZ, UK
| | - Pierre Larraufie
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Julie Jerber
- The Anne McLaren Laboratory for Regenerative Medicine, Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, CB2 0SZ, UK; Open Targets, Wellcome Trust Sanger Institute, Hinxton, CB10 1SA, UK
| | - Jason Pembroke
- LGC Ltd., Newmarket Road, Fordham, Cambridgeshire, CB7 5WW, UK
| | - Theresa Bartels
- The Anne McLaren Laboratory for Regenerative Medicine, Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, CB2 0SZ, UK
| | - Anne White
- Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Fiona M Gribble
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Frank Reimann
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - I Sadaf Farooqi
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Stephen O'Rahilly
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Florian T Merkle
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK; The Anne McLaren Laboratory for Regenerative Medicine, Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, CB2 0SZ, UK.
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Wang L, Sui L, Panigrahi SK, Meece K, Xin Y, Kim J, Gromada J, Doege CA, Wardlaw SL, Egli D, Leibel RL. PC1/3 Deficiency Impacts Pro-opiomelanocortin Processing in Human Embryonic Stem Cell-Derived Hypothalamic Neurons. Stem Cell Reports 2017; 8:264-277. [PMID: 28132887 PMCID: PMC5312251 DOI: 10.1016/j.stemcr.2016.12.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 12/20/2016] [Accepted: 12/21/2016] [Indexed: 12/19/2022] Open
Abstract
We recently developed a technique for generating hypothalamic neurons from human pluripotent stem cells. Here, as proof of principle, we examine the use of these cells in modeling of a monogenic form of severe obesity: PCSK1 deficiency. The cognate enzyme, PC1/3, processes many prohormones in neuroendocrine and other tissues. We generated PCSK1 (PC1/3)-deficient human embryonic stem cell (hESC) lines using both short hairpin RNA and CRISPR-Cas9, and investigated pro-opiomelanocortin (POMC) processing using hESC-differentiated hypothalamic neurons. The increased levels of unprocessed POMC and the decreased ratios (relative to POMC) of processed POMC-derived peptides in both PCSK1 knockdown and knockout hESC-derived neurons phenocopied POMC processing reported in PC1/3-null mice and PC1/3-deficient patients. PC1/3 deficiency was associated with increased expression of melanocortin receptors and PRCP (prolylcarboxypeptidase, a catabolic enzyme for α-melanocyte stimulating hormone (αMSH)), and reduced adrenocorticotropic hormone secretion. We conclude that the obesity accompanying PCSK1 deficiency may not be primarily due to αMSH deficiency. Stem cell-derived hypothalamic neurons are used to study human obesity shRNA and CRISPR-Cas9 were used to generate models of PCSK1 deficiency PC1/3 deficiency impaired POMC processing in arcuate-like neurons Adaptive changes occurred in “downstream” POMC processing enzymes
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Affiliation(s)
- Liheng Wang
- Division of Molecular Genetics, Department of Pediatrics and Naomi Berrie Diabetes Center, College of Physicians and Surgeons, Columbia University, 1150 St. Nicholas Avenue, Room 620A, New York, NY 10032, USA; Department of Medicine and Naomi Berrie Diabetes Center, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Lina Sui
- Division of Molecular Genetics, Department of Pediatrics and Naomi Berrie Diabetes Center, College of Physicians and Surgeons, Columbia University, 1150 St. Nicholas Avenue, Room 620A, New York, NY 10032, USA
| | - Sunil K Panigrahi
- Department of Medicine and Naomi Berrie Diabetes Center, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Kana Meece
- Department of Medicine and Naomi Berrie Diabetes Center, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Yurong Xin
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Jinrang Kim
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | - Claudia A Doege
- Department of Pathology and Cell Biology and Naomi Berrie Diabetes Center, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Sharon L Wardlaw
- Department of Medicine and Naomi Berrie Diabetes Center, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Dieter Egli
- Division of Molecular Genetics, Department of Pediatrics and Naomi Berrie Diabetes Center, College of Physicians and Surgeons, Columbia University, 1150 St. Nicholas Avenue, Room 620A, New York, NY 10032, USA; New York Stem Cell Foundation Research Institute, 3960 Broadway, New York, NY 10032, USA
| | - Rudolph L Leibel
- Division of Molecular Genetics, Department of Pediatrics and Naomi Berrie Diabetes Center, College of Physicians and Surgeons, Columbia University, 1150 St. Nicholas Avenue, Room 620A, New York, NY 10032, USA; Department of Medicine and Naomi Berrie Diabetes Center, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
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Page-Wilson G, Meece K, White A, Rosenbaum M, Leibel RL, Smiley R, Wardlaw SL. Proopiomelanocortin, agouti-related protein, and leptin in human cerebrospinal fluid: correlations with body weight and adiposity. Am J Physiol Endocrinol Metab 2015; 309:E458-65. [PMID: 26152765 PMCID: PMC4556883 DOI: 10.1152/ajpendo.00206.2015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 07/01/2015] [Indexed: 11/22/2022]
Abstract
Leptin and its neuronal targets, which produce proopiomelanocortin (POMC) and agouti-related protein (AgRP), regulate energy balance. This study characterized leptin, POMC, and AgRP in the cerebrospinal fluid (CSF) of 47 healthy human subjects, 23 lean and 24 overweight/obese (OW/OB), as related to BMI, adiposity, plasma leptin, soluble leptin receptor (s-OB-R), and insulin. POMC was measured since the POMC prohormone is the predominant POMC peptide in CSF and correlates with hypothalamic POMC in rodents. Plasma AgRP was similarly characterized. CSF leptin was 83-fold lower than in plasma and correlated strongly with BMI, body fat, and insulin. The relative amount of leptin transported into CSF declined with increasing BMI, ranging from 4.5 to 0.52%, consistent with a saturable transport mechanism. CSF sOB-R was 78-fold lower than in plasma and correlated negatively with plasma and CSF leptin. CSF POMC was higher in lean vs. OW/OB subjects (P < 0.001) and correlated negatively with CSF leptin (r = -0.60, P < 0.001) and with plasma leptin, insulin, BMI, and adiposity. CSF AgRP was not different in lean vs. OW/OB; however, plasma AgRP was higher in lean subjects (P = 0.001) and correlated negatively with BMI, adiposity, leptin, insulin, and HOMA (P < 0.005). Thus, CSF measurements may provide useful biomarkers for brain leptin and POMC activity. The striking negative correlation between CSF leptin and POMC could be secondary to leptin resistance and/or neuronal changes associated with obesity but may also indicate that POMC plays a primary role in regulating body weight and adiposity. The role of plasma AgRP as a neuroendocrine biomarker deserves further study.
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Affiliation(s)
- Gabrielle Page-Wilson
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York
| | - Kana Meece
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York
| | - Anne White
- Faculties of Life Sciences and Medical and Human Sciences, University of Manchester, Manchester, United Kingdom
| | - Michael Rosenbaum
- Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, New York; and
| | - Rudolph L Leibel
- Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, New York; and
| | - Richard Smiley
- Department of Anesthesiology, Columbia University College of Physicians and Surgeons, New York, New York
| | - Sharon L Wardlaw
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York;
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Wardlaw SL, Burant CF, Klein S, Meece K, White A, Kasten T, Lucey BP, Bateman RJ. Continuous 24-hour leptin, proopiomelanocortin, and amino acid measurements in human cerebrospinal fluid: correlations with plasma leptin, soluble leptin receptor, and amino acid levels. J Clin Endocrinol Metab 2014; 99:2540-8. [PMID: 24670082 PMCID: PMC4079306 DOI: 10.1210/jc.2013-4087] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
CONTEXT In order to characterize diurnal changes in central leptin and its target neuropeptide, proopiomelanocortin (POMC), we measured leptin and POMC in cerebrospinal fluid (CSF) as related to changes in plasma leptin and soluble leptin receptor (sOB-R) levels. CSF and plasma levels of 20 amino acids (AA) were also measured because AA can affect brain POMC. DESIGN AND PARTICIPANTS Stored CSF and plasma samples obtained from eight healthy subjects who served as controls for a previous study were evaluated. CSF was collected hourly over 33 h via indwelling subarachnoid catheter. Leptin, sOB-R, and POMC were measured by sensitive ELISA and AA by gas chromatography-mass spectrometry. RESULTS There was a diurnal rhythm for plasma leptin with a peak at 2200 h (144% of baseline) and there was a similar diurnal rhythm for CSF leptin with a peak (117%) 3-5 h after the plasma peak. Plasma sOB-R was lowest at 0300 h and correlated negatively with plasma and CSF leptin. A diurnal rhythm for POMC in CSF was also detected with a peak (125%) at 0100 h. A positive correlation existed between CSF POMC and leptin in individual subjects over time. CSF levels of many AA increased at night. There was a significant correlation between CSF POMC and 10 AA, including leucine, isoleucine, tryptophan, and tyrosine. CONCLUSIONS Diurnal changes occur in leptin and POMC in human CSF that likely reflect changes in central leptin and melanocortin activity. Our results suggest that nocturnal elevations in leptin, AA, and POMC may help to suppress appetite and feeding at night.
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Affiliation(s)
- Sharon L Wardlaw
- Department of Medicine (S.L.W., K.M.), Columbia University College of Physicians & Surgeons, New York, New York 10032; Department of Internal Medicine (C.F.B.), University of Michigan Medical School, Ann Arbor, Michigan 48019; Center for Human Nutrition and Atkins Center for Excellence in Obesity Medicine (S.K.), Washington University School of Medicine, St Louis, Missouri 63110; Faculties of Life Sciences and Medical and Human Sciences (A.W.), University of Manchester, Manchester M13 9PL, United Kingdom; and Department of Neurology (T.K., B.P.L., R.J.B), Washington University School of Medicine, St Louis, Missouri 63110
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Mercer AJ, Hentges ST, Meshul CK, Low MJ. Unraveling the central proopiomelanocortin neural circuits. Front Neurosci 2013; 7:19. [PMID: 23440036 PMCID: PMC3579188 DOI: 10.3389/fnins.2013.00019] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 02/04/2013] [Indexed: 11/16/2022] Open
Abstract
Central proopiomelanocortin (POMC) neurons form a potent anorexigenic network, but our understanding of the integration of this hypothalamic circuit throughout the central nervous system (CNS) remains incomplete. POMC neurons extend projections along the rostrocaudal axis of the brain, and can signal with both POMC-derived peptides and fast amino acid neurotransmitters. Although recent experimental advances in circuit-level manipulation have been applied to POMC neurons, many pivotal questions still remain: how and where do POMC neurons integrate metabolic information? Under what conditions do POMC neurons release bioactive molecules throughout the CNS? Are GABA and glutamate or neuropeptides released from POMC neurons more crucial for modulating feeding and metabolism? Resolving the exact stoichiometry of signals evoked from POMC neurons under different metabolic conditions therefore remains an ongoing endeavor. In this review, we analyze the anatomical atlas of this network juxtaposed to the physiological signaling of POMC neurons both in vitro and in vivo. We also consider novel genetic tools to further characterize the function of the POMC circuit in vivo. Our goal is to synthesize a global view of the POMC network, and to highlight gaps that require further research to expand our knowledge on how these neurons modulate energy balance.
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Affiliation(s)
- Aaron J Mercer
- Department of Molecular and Integrative Physiology, University of Michigan Ann Arbor, MI, USA
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pRb is an obesity suppressor in hypothalamus and high-fat diet inhibits pRb in this location. EMBO J 2013; 32:844-57. [PMID: 23403926 DOI: 10.1038/emboj.2013.25] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 01/21/2013] [Indexed: 12/27/2022] Open
Abstract
pRb is frequently inactivated in tumours by mutations or phosphorylation. Here, we investigated whether pRb plays a role in obesity. The Arcuate nucleus (ARC) in hypothalamus contains antagonizing POMC and AGRP/NPY neurons for negative and positive energy balance, respectively. Various aspects of ARC neurons are affected in high-fat diet (HFD)-induced obesity mouse model. Using this model, we show that HFD, as well as pharmacological activation of AMPK, induces pRb phosphorylation and E2F target gene de-repression in ARC neurons. Some affected neurons express POMC; and deleting Rb1 in POMC neurons induces E2F target gene de-repression, cell-cycle re-entry, apoptosis, and a hyperphagia-obesity-diabetes syndrome. These defects can be corrected by combined deletion of E2f1. In contrast, deleting Rb1 in the antagonizing AGRP/NPY neurons shows no effects. Thus, pRb-E2F1 is an obesity suppression mechanism in ARC POMC neurons and HFD-AMPK inhibits this mechanism by phosphorylating pRb in this location.
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Page-Wilson G, Reitman-Ivashkov E, Meece K, White A, Rosenbaum M, Smiley RM, Wardlaw SL. Cerebrospinal fluid levels of leptin, proopiomelanocortin, and agouti-related protein in human pregnancy: evidence for leptin resistance. J Clin Endocrinol Metab 2013; 98:264-71. [PMID: 23118421 PMCID: PMC3537103 DOI: 10.1210/jc.2012-2309] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Leptin suppresses appetite by modulating the expression of hypothalamic neuropeptides including proopiomelanocortin (POMC) and agouti-related peptide (AgRP). Yet during pregnancy, caloric consumption increases despite elevated plasma leptin levels. DESIGN AND PARTICIPANTS To investigate this paradox, we measured leptin and soluble leptin receptor in plasma and leptin, POMC, and AgRP in cerebrospinal fluid (CSF) from 21 fasting pregnant women before delivery by cesarean section at a university hospital and from 14 fasting nonpregnant women. RESULTS Prepregnancy body mass index was 24.6 ± 1.1 (SE) vs. 31.3 ± 1.3 at term vs. 26.5 ± 1.6 kg/m(2) in controls. Plasma leptin (32.9 ± 4.6 vs. 16.7 ± 3.0 ng/ml) and soluble leptin receptor (30.9 ± 2.3 vs. 22.1 ± 1.4 ng/ml) levels were significantly higher in pregnant women. However, mean CSF leptin did not differ between the two groups (283 ± 34 vs. 311 ± 32 pg/ml), consistent with a relative decrease in leptin transport into CSF during pregnancy. Accordingly, the CSF/plasma leptin percentage was 1.0 ± 0.01% in pregnant subjects vs. 2.1 ± 0.2% in controls (P < 0.0001). Mean CSF AgRP was significantly higher in pregnant subjects (32.3 ± 2.7 vs. 23.5 ± 2.5 pg/ml; P = 0.03). Mean CSF POMC was not significantly different in pregnant subjects (200 ± 13.6 vs. 229 ± 17.3 fmol/ml; P = 0.190). However, the mean AgRP/POMC ratio was significantly higher among pregnant women (P = 0.003), consistent with an overall decrease in melanocortin tone favoring increased food intake during pregnancy. CONCLUSIONS These data demonstrate that despite peripheral hyperleptinemia, positive energy balance is achieved during pregnancy by a relative decrease in central leptin concentrations and resistance to leptin's effects on target neuropeptides that regulate energy balance.
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Volume transmission of beta-endorphin via the cerebrospinal fluid; a review. Fluids Barriers CNS 2012; 9:16. [PMID: 22883598 PMCID: PMC3439317 DOI: 10.1186/2045-8118-9-16] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 07/07/2012] [Indexed: 02/08/2023] Open
Abstract
There is increasing evidence that non-synaptic communication by volume transmission in the flowing CSF plays an important role in neural mechanisms, especially for extending the duration of behavioral effects. In the present review, we explore the mechanisms involved in the behavioral and physiological effects of β-endorphin (β-END), especially those involving the cerebrospinal fluid (CSF), as a message transport system to reach distant brain areas. The major source of β-END are the pro-opio-melano-cortin (POMC) neurons, located in the arcuate hypothalamic nucleus (ARH), bordering the 3rd ventricle. In addition, numerous varicose β-END-immunoreactive fibers are situated close to the ventricular surfaces. In the present paper we surveyed the evidence that volume transmission via the CSF can be considered as an option for messages to reach remote brain areas. Some of the points discussed in the present review are: release mechanisms of β-END, independence of peripheral versus central levels, central β-END migration over considerable distances, behavioral effects of β-END depend on location of ventricular administration, and abundance of mu and delta opioid receptors in the periventricular regions of the brain.
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Stanley B, Sher L, Wilson S, Ekman R, Huang YY, Mann JJ. Non-suicidal self-injurious behavior, endogenous opioids and monoamine neurotransmitters. J Affect Disord 2010; 124:134-40. [PMID: 19942295 PMCID: PMC2875354 DOI: 10.1016/j.jad.2009.10.028] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 09/23/2009] [Accepted: 10/29/2009] [Indexed: 12/23/2022]
Abstract
BACKGROUND Self-inflicted injury, including cutting or burning, is the most frequent reason for psychiatric visits to medical emergency departments. This behavior, particularly when there is no apparent suicidal intent, is poorly understood from both biological and clinical perspectives. OBJECTIVE To examine the role of endogenous opioids and monoamine neurotransmitters in non-suicidal self-injury (NSSI). METHODS We compared cerebrospinal fluid (CSF) levels of endogenous opioids, 5 hydroxyindolacetic acid (5-HIAA) and homovanillic acid (HVA) in individuals with a history of repetitive non-suicidal self-injury with a diagnostically-matched group of individuals who had never engaged in non-suicidal self-injury. History of suicidal behavior, demographic background and psychopathology was assessed. All patients were diagnosed with a Cluster B personality disorder (i.e. borderline, antisocial, narcissistic or histrionic) (N=29) and had a history of at least one suicide attempt. Fourteen participants had a history of repeated non-suicidal self-injurious behavior (NSSI) in adulthood and 15 did not (no NSSI). RESULTS The NSSI group had significantly lower levels of CSF beta-endorphin and met-enkephalin when compared with the non-NSSI group. CSF dynorphin, HVA and 5-HIAA levels did not differ. Severity of depression, hopelessness and overall psychopathology was greater in the NSSI group. CONCLUSION beta-endorphin and met-enkephalin, opioids acting upon receptors involved in mediating stress-induced and physical pain analgesia respectively, are implicated in NSSI. Serotonergic and dopaminergic dysfunctions do not appear to be related to NSSI. Based on our findings, we propose a model of non-suicidal self-injury. Our results suggest that drugs acting on the opioid system warrant exploration as pharmacological treatments for NSSI.
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Affiliation(s)
- Barbara Stanley
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, New York, New York 10032, USA.
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Xiao E, Kim AJ, Dutia R, Conwell I, Ferin M, Wardlaw SL. Effects of estradiol on cerebrospinal fluid levels of agouti-related protein in ovariectomized rhesus monkeys. Endocrinology 2010; 151:1002-9. [PMID: 20056830 PMCID: PMC2840683 DOI: 10.1210/en.2009-0853] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Hypothalamic proopiomelanocortin (POMC)-derived MSH peptides and the melanocortin receptor antagonist, agouti-related protein (AgRP), interact to regulate energy balance. Both POMC and AgRP neurons express estrogen receptors, but little is known about estrogen regulation of the melanocortin system in the primate. We have therefore examined the effects of physiological doses of estradiol (E2) on POMC and AgRP in lumbar cerebrospinal fluid (CSF) of ovariectomized monkeys. POMC prohormone was measured by ELISA. AgRP was measured by RIA (sensitive for the more biologically active C-terminal AgRP(83-132) but also detects full-length AgRP) and by ELISA (measures primarily full length AgRP). In the first experiment, 14 animals were studied before and after 3 wk of E2. CSF POMC did not change, but AgRP(RIA) decreased from 7.9 +/- 1.2 to 4.7 +/- 1.2 fmol/ml after E2 (P = 0.03) and the POMC/AgRP(RIA) ratio increased from 4.2 +/- 0.89 to 6.8 +/- 1.04 (P = 0.04). AgRP(ELISA) did not change, but the ratio of AgRP(RIA) compared with AgRP(ELISA) was reduced after E2 (P = 0.02). In the second experiment, 11 animals were studied after 6 wk of E2, and similar changes were noted. The degree of AgRP(RIA) suppression with E2 was inversely related to body mass index (r = 0.569; P = 0.03). These results show for the first time that E2 suppresses AgRP(C-terminal) in CSF, increases the POMC to AgRP ratio, and may decrease AgRP processing, thus leading to increased melanocortin signaling. Furthermore, obesity was associated with resistance to the suppressive effects of E2 on AgRP, analogous to what is seen with obesity and leptin resistance.
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Affiliation(s)
- Ennian Xiao
- Department of Medicine, Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, New York 10032, USA
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Plum L, Lin HV, Dutia R, Tanaka J, Aizawa KS, Matsumoto M, Kim AJ, Cawley NX, Paik JH, Loh YP, DePinho RA, Wardlaw SL, Accili D. The obesity susceptibility gene Cpe links FoxO1 signaling in hypothalamic pro-opiomelanocortin neurons with regulation of food intake. Nat Med 2009; 15:1195-201. [PMID: 19767734 PMCID: PMC2777744 DOI: 10.1038/nm.2026] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Accepted: 08/11/2009] [Indexed: 12/03/2022]
Abstract
Reduced food intake brings about an adaptive decrease in energy expenditure that contributes to the recidivism of obesity following weight loss. Insulin and leptin inhibit food intake through actions in the central nervous system that are partly mediated by FoxO1. We show that FoxO1 ablation in pro–opiomelanocortin (Pomc) neurons (Pomc–Foxo1−/−) reduces food intake without affecting energy expenditure. Analyses of hypothalamic neuropeptides in Pomc–Foxo1−/− mice reveal selective increases of α–Msh and COOH–cleaved β–endorphin, the products of Carboxypeptidase E (Cpe)–dependent processing of Pomc. We show that Cpe is decreased in diet–induced obesity, and that FoxO1 deletion offsets the decrease, protecting against weight gain. Moreover, moderate Cpe overexpression in the arcuate nucleus phenocopies features of the FoxO1 mutation. The dissociation of food intake from energy expenditure in Pomc–Foxo1−/− mice represents a model for therapeutic intervention in obesity, and raises the possibility of targeting Cpe to develop weight loss medications.
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Affiliation(s)
- Leona Plum
- Naomi Berrie Diabetes Center and Department of Medicine, Columbia University, New York, New York, USA
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Millington GW. The role of proopiomelanocortin (POMC) neurones in feeding behaviour. Nutr Metab (Lond) 2007; 4:18. [PMID: 17764572 PMCID: PMC2018708 DOI: 10.1186/1743-7075-4-18] [Citation(s) in RCA: 210] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2007] [Accepted: 09/01/2007] [Indexed: 12/15/2022] Open
Abstract
The precursor protein, proopiomelanocortin (POMC), produces many biologically active peptides via a series of enzymatic steps in a tissue-specific manner, yielding the melanocyte-stimulating hormones (MSHs), corticotrophin (ACTH) and β-endorphin. The MSHs and ACTH bind to the extracellular G-protein coupled melanocortin receptors (MCRs) of which there are five subtypes. The MC3R and MC4R show widespread expression in the central nervous system (CNS), whilst there is low level expression of MC1R and MC5R. In the CNS, cell bodies for POMC are mainly located in the arcuate nucleus of the hypothalamus and the nucleus tractus solitarius of the brainstem. Both of these areas have well defined functions relating to appetite and food intake. Mouse knockouts (ko) for pomc, mc4r and mc3r all show an obese phenotype, as do humans expressing mutations of POMC and MC4R. Recently, human subjects with specific mutations in β-MSH have been found to be obese too, as have mice with engineered β-endorphin deficiency. The CNS POMC system has other functions, including regulation of sexual behaviour, lactation, the reproductive cycle and possibly central cardiovascular control. However, this review will focus on feeding behaviour and link it in with the neuroanatomy of the POMC neurones in the hypothalamus and brainstem.
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Affiliation(s)
- George Wm Millington
- Division of Medicine, Norfolk and Norwich University Hospital, Colney Lane, Norwich, NR4 7UZ, UK.
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