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Son JE, Dou Z, Wanggou S, Chan J, Mo R, Li X, Huang X, Kim KH, Michaud JL, Hui CC. Ectopic expression of Irx3 and Irx5 in the paraventricular nucleus of the hypothalamus contributes to defects in Sim1 haploinsufficiency. SCIENCE ADVANCES 2021; 7:eabh4503. [PMID: 34705510 PMCID: PMC8550250 DOI: 10.1126/sciadv.abh4503] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 09/03/2021] [Indexed: 06/13/2023]
Abstract
The paraventricular nucleus of the hypothalamus (PVH) contains a heterogeneous cluster of Sim1-expressing neurons critical for feeding regulation. Sim1 haploinsufficiency results in hyperphagic obesity with disruption of PVH neurons, yet the molecular profiles of PVH neurons and the mechanism underlying the defects of Sim1 haploinsufficiency are not well understood. By single-cell RNA sequencing, we identified two major populations of Sim1+ PVH neurons, which are differentially affected by Sim1 haploinsufficiency. The Iroquois homeobox genes Irx3 and Irx5 have been implicated in the hypothalamic control of energy homeostasis. We found that Irx3 and Irx5 are ectopically expressed in the Sim1+ PVH cells of Sim1+/− mice. By reducing their dosage and PVH-specific deletion of Irx3, we demonstrate that misexpression of Irx3 and Irx5 contributes to the defects of Sim1+/− mice. Our results illustrate abnormal hypothalamic activities of Irx3 and Irx5 as a central mechanism disrupting PVH development and feeding regulation in Sim1 haploinsufficiency.
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Affiliation(s)
- Joe Eun Son
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Zhengchao Dou
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Siyi Wanggou
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Hunan International Scientific and Technological Cooperation Base of Brain Tumor Research, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Jade Chan
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Rong Mo
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Xuejun Li
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Hunan International Scientific and Technological Cooperation Base of Brain Tumor Research, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Xi Huang
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Kyoung-Han Kim
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Jacques L. Michaud
- CHU Sainte-Justine Research Center, Montreal, QC H3T 1C5, Canada
- Departments of Pediatrics and Neurosciences, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Chi-chung Hui
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
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Pirník Z, Kořínková L, Osacká J, Železná B, Kuneš J, Maletínská L. Cholecystokinin system is involved in the anorexigenic effect of peripherally applied palmitoylated prolactin-releasing peptide in fasted mice. Physiol Res 2021; 70:579-590. [PMID: 34062082 PMCID: PMC8820541 DOI: 10.33549/physiolres.934694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 04/22/2021] [Indexed: 11/25/2022] Open
Abstract
Prolactin-releasing peptide (PrRP) has been proposed to mediate the central satiating effects of cholecystokinin (CCK) through the vagal CCK1 receptor. PrRP acts as an endogenous ligand of G protein-coupled receptor 10 (GPR10), which is expressed at the highest levels in brain areas related to food intake regulation, e.g., the paraventricular hypothalamic nucleus (PVN) and nucleus of the solitary tract (NTS). The NTS and PVN are also significantly activated after peripheral CCK administration. The aim of this study was to determine whether the endogenous PrRP neuronal system in the brain is involved in the central anorexigenic effect of the peripherally administered CCK agonist JMV236 or the CCK1 antagonist devazepide and whether the CCK system is involved in the central anorexigenic effect of the peripherally applied lipidized PrRP analog palm-PrRP31 in fasted lean mice. The effect of devazepide and JMV236 on the anorexigenic effects of palm-PrRP31 as well as devazepide combined with JMV236 and palm-PrRP31 on food intake and Fos cell activation in the PVN and caudal NTS was examined. Our results suggest that the anorexigenic effect of JMV236 is accompanied by activation of PrRP neurons of the NTS in a CCK1 receptor-dependent manner. Moreover, while the anorexigenic effect of palm-PrRP31 was not affected by JMV236, it was partially attenuated by devazepide in fasted mice. The present findings indicate that the exogenously influenced CCK system may be involved in the central anorexigenic effect of peripherally applied palm-PrRP31, which possibly indicates some interaction between the CCK and PrRP neuronal systems.
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Affiliation(s)
- Z Pirník
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic,
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Maejima Y, Horita S, Otsuka A, Hidema S, Nishimori K, Shimomura K. Oral oxytocin delivery with proton pump inhibitor pretreatment decreases food intake. Peptides 2020; 128:170312. [PMID: 32298773 DOI: 10.1016/j.peptides.2020.170312] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 04/06/2020] [Accepted: 04/06/2020] [Indexed: 12/25/2022]
Abstract
Oxytocin (Oxt) is considered as a potential agent to treat multiple neuropsychiatric disorders, obesity and metabolic syndrome. Although the mechanisms underlying these effects remain unclear, nasal administration is considered to be a potential way to deliver Oxt into blood vessels. The development of an easier, more stable and efficient way is expected. A recent study demonstrated that orally administered Oxt can be transmitted into blood if it is prevented from degradation in stomach and reaches the intestinal tract. In this study, we pretreated mice with a proton pump inhibitor (PPI), omeprazole (20 mg/kg), and administered capsulized Oxt (0.25 mg), so that the Oxt can be prevented from degradation by pepsin due to the low pH in stomach and reach the intestinal tract. Functionally, these mice showed a similar decrease in food intake to those who underwent intraperitoneal administration. We also confirmed that this method dramatically increased plasma Oxt levels and the expression of neural activation marker c-Fos protein in the paraventricular and suprachiasmatic nucleus. Our study showed that by pretreating mice with PPI, Oxt in a gelatin-coated capsule can prevent Oxt from degradation by pepsin in stomach, and reach the bloodstream in an effective concentration. These results indicate that our method is a promising oral delivery of Oxt and should be investigated further for other peptide agents based on peripheral injection or nasal administration.
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Affiliation(s)
- Yuko Maejima
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, 960-1295, Fukushima, Japan.
| | - Shoichiro Horita
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, 960-1295, Fukushima, Japan
| | - Ayano Otsuka
- Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University Sendai-shi, 981-8555, Miyagi, Japan
| | - Shizu Hidema
- Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University Sendai-shi, 981-8555, Miyagi, Japan
| | - Katsuhiko Nishimori
- Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University Sendai-shi, 981-8555, Miyagi, Japan
| | - Kenju Shimomura
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, 960-1295, Fukushima, Japan
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Lee EY, Hwang YG, Lee HS. Hypothalamic neuronal origin of neuropeptide Y (NPY) or cocaine- and amphetamine-regulated transcript (CART) fibers projecting to the tuberomammillary nucleus of the rat. Brain Res 2017; 1657:16-28. [DOI: 10.1016/j.brainres.2016.11.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 11/17/2016] [Accepted: 11/21/2016] [Indexed: 12/25/2022]
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Engster KM, Frommelt L, Hofmann T, Nolte S, Fischer F, Rose M, Stengel A, Kobelt P. Peripheral injected cholecystokinin-8S modulates the concentration of serotonin in nerve fibers of the rat brainstem. Peptides 2014; 59:25-33. [PMID: 25017242 DOI: 10.1016/j.peptides.2014.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 07/02/2014] [Accepted: 07/02/2014] [Indexed: 02/05/2023]
Abstract
Serotonin and cholecystokinin (CCK) play a role in the short-term inhibition of food intake. It is known that peripheral injection of CCK increases c-Fos-immunoreactivity (Fos-IR) in the nucleus of the solitary tract (NTS) in rats, and injection of the serotonin antagonist ondansetron decreases the number of c-Fos-IR cells in the NTS. This supports the idea of serotonin contributing to the effects of CCK. The aim of the present study was to elucidate whether peripherally injected CCK-8S modulates the concentration of serotonin in brain feeding-regulatory nuclei. Ad libitum fed male Sprague-Dawley rats received 5.2 and 8.7 nmol/kg CCK-8S (n=3/group) or 0.15M NaCl (n=3-5/group) injected intraperitoneally (ip). The number of c-Fos-IR neurons, and the fluorescence intensity of serotonin in nerve fibers were assessed in the paraventricular nucleus (PVN), arcuate nucleus (ARC), NTS and dorsal motor nucleus of the vagus (DMV). CCK-8S increased the number of c-Fos-ir neurons in the NTS (mean±SEM: 72±4, and 112±5 neurons/section, respectively) compared to vehicle-treated rats (7±2 neurons/section, P<0.05), but did not modulate c-Fos expression in the DMV or ARC. Additionally, CCK-8S dose-dependently increased the number of c-Fos-positive neurons in the PVN (218±15 and 128±14, respectively vs. 19±5, P<0.05). In the NTS and DMV we observed a decrease of serotonin-immunoreactivity 90 min after injection of CCK-8S (46±2 and 49±8 pixel/section, respectively) compared to vehicle (81±8 pixel/section, P<0.05). No changes of serotonin-immunoreactivity were observed in the PVN and ARC. Our results suggest that serotonin is involved in the mediation of CCK-8's effects in the brainstem.
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Affiliation(s)
- Kim-Marie Engster
- Medical Clinic, Department of Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Germany
| | - Lisa Frommelt
- Medical Clinic, Department of Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Germany
| | - Tobias Hofmann
- Medical Clinic, Department of Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Germany
| | - Sandra Nolte
- Medical Clinic, Department of Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Germany
| | - Felix Fischer
- Medical Clinic, Department of Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Germany
| | - Matthias Rose
- Medical Clinic, Department of Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Germany
| | - Andreas Stengel
- Medical Clinic, Department of Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Germany
| | - Peter Kobelt
- Medical Clinic, Department of Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Germany.
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Subhedar NK, Nakhate KT, Upadhya MA, Kokare DM. CART in the brain of vertebrates: circuits, functions and evolution. Peptides 2014; 54:108-30. [PMID: 24468550 DOI: 10.1016/j.peptides.2014.01.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 01/10/2014] [Accepted: 01/10/2014] [Indexed: 12/12/2022]
Abstract
Cocaine- and amphetamine-regulated transcript peptide (CART) with its wide distribution in the brain of mammals has been the focus of considerable research in recent years. Last two decades have witnessed a steady rise in the information on the genes that encode this neuropeptide and regulation of its transcription and translation. CART is highly enriched in the hypothalamic nuclei and its relevance to energy homeostasis and neuroendocrine control has been understood in great details. However, the occurrence of this peptide in a range of diverse circuitries for sensory, motor, vegetative, limbic and higher cortical areas has been confounding. Evidence that CART peptide may have role in addiction, pain, reward, learning and memory, cognition, sleep, reproduction and development, modulation of behavior and regulation of autonomic nervous system are accumulating, but an integration has been missing. A steady stream of papers has been pointing at the therapeutic potentials of CART. The current review is an attempt at piecing together the fragments of available information, and seeks meaning out of the CART elements in their anatomical niche. We try to put together the CART containing neuronal circuitries that have been conclusively demonstrated as well as those which have been proposed, but need confirmation. With a view to finding out the evolutionary antecedents, we visit the CART systems in sub-mammalian vertebrates and seek the answer why the system is shaped the way it is. We enquire into the conservation of the CART system and appreciate its functional diversity across the phyla.
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Affiliation(s)
- Nishikant K Subhedar
- Indian Institute of Science Education and Research (IISER), Sai Trinity Building, Sutarwadi, Pashan, Pune 411 021, Maharashtra, India.
| | - Kartik T Nakhate
- Rungta College of Pharmaceutical Sciences and Research, Rungta Educational Campus, Kohka-Kurud Road, Bhilai 490 024, Chhattisgarh, India
| | - Manoj A Upadhya
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440 033, Maharashtra, India
| | - Dadasaheb M Kokare
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440 033, Maharashtra, India
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Penney CC, Volkoff H. Peripheral injections of cholecystokinin, apelin, ghrelin and orexin in cavefish (Astyanax fasciatus mexicanus): effects on feeding and on the brain expression levels of tyrosine hydroxylase, mechanistic target of rapamycin and appetite-related hormones. Gen Comp Endocrinol 2014; 196:34-40. [PMID: 24287340 DOI: 10.1016/j.ygcen.2013.11.015] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 11/15/2013] [Accepted: 11/18/2013] [Indexed: 12/27/2022]
Abstract
The effects of intraperitoneal injections of cholecystokinin (CCK), apelin, ghrelin, and orexin on food intake were examined in the blind cavefish Astyanax fasciatus mexicanus. CCK (50ng/g) induced a decrease in food intake whereas apelin (100ng/g), orexin (100ng/g), and ghrelin (100ng/g) induced an increase in food intake as compared to saline-injected control fish. In order to better understand the central mechanism by which these hormones act, we examined the effects of injections on the brain mRNA expression of two metabolic enzymes, tyrosine hydroxylase (TH), and mechanistic target of rapamycin (mTOR), and of appetite-regulating peptides, CCK, orexin, apelin and cocaine and amphetamine regulated transcript (CART). CCK injections induced a decrease in brain apelin injections, apelin injections induced an increase in TH, mTOR, and orexin brain expressions, orexin treatment increased brain TH expression and ghrelin injections induced an increase in mTOR and orexin brain expressions. CART expression was not affected by any of the injection treatments. Our results suggest that the enzymes TH and mTOR and the hormones CCK, apelin, orexin, and ghrelin all regulate food intake in cavefish through a complex network of interactions.
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Affiliation(s)
- Carla C Penney
- Departments of Biology and Biochemistry, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada
| | - Hélène Volkoff
- Departments of Biology and Biochemistry, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
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Insulin Activates Vagal Afferent Neurons Including those Innervating Pancreas via Insulin Cascade and Ca(2+) Influx: Its Dysfunction in IRS2-KO Mice with Hyperphagic Obesity. PLoS One 2013; 8:e67198. [PMID: 23840624 PMCID: PMC3693960 DOI: 10.1371/journal.pone.0067198] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 05/15/2013] [Indexed: 11/19/2022] Open
Abstract
Some of insulin’s functions, including glucose/lipid metabolism, satiety and neuroprotection, involve the alteration of brain activities. Insulin could signal to the brain via penetrating through the blood-brain barrier and acting on the vagal afferents, while the latter remains unproved. This study aimed to clarify whether insulin directly regulates the nodose ganglion neurons (NGNs) of vagal afferents in mice. NGs expressed insulin receptor (IR) and insulin receptor substrate-2 (IRS2) mRNA, and some of NGNs were immunoreactive to IR. In patch-clamp and fura-2 microfluorometric studies, insulin (10−12∼10−6 M) depolarized and increased cytosolic Ca2+ concentration ([Ca2+]i) in single NGNs. The insulin-induced [Ca2+]i increases were attenuated by L- and N-type Ca2+ channel blockers, by phosphatidylinositol 3 kinase (PI3K) inhibitor, and in NGNs from IRS2 knockout mice. Half of the insulin-responsive NGNs contained cocaine- and amphetamine-regulated transcript. Neuronal fibers expressing IRs were distributed in/around pancreatic islets. The NGNs innervating the pancreas, identified by injecting retrograde tracer into the pancreas, responded to insulin with much greater incidence than unlabeled NGNs. Insulin concentrations measured in pancreatic vein was 64-fold higher than that in circulation. Elevation of insulin to 10−7 M recruited a remarkably greater population of NGNs to [Ca2+]i increases. Systemic injection of glibenclamide rapidly released insulin and phosphorylated AKT in NGs. Furthermore, in IRS2 knockout mice, insulin action to suppress [Ca2+]i in orexigenic ghrelin-responsive neurons in hypothalamic arcuate nucleus was intact while insulin action on NGN was markedly attenuated, suggesting a possible link between impaired insulin sensing by NGNs and hyperphagic obese phenotype in IRS2 knockout mice These data demonstrate that insulin directly activates NGNs via IR-IRS2-PI3K-AKT-cascade and depolarization-gated Ca2+ influx. Pancreas-innervating NGNs may effectively sense dynamic changes of insulin released in response to nutritional states. These interactions could serve to convey the changes in pancreatic and systemic insulin to the brain.
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Yamashita M, Takayanagi Y, Yoshida M, Nishimori K, Kusama M, Onaka T. Involvement of prolactin-releasing peptide in the activation of oxytocin neurones in response to food intake. J Neuroendocrinol 2013; 25:455-65. [PMID: 23363338 PMCID: PMC3664423 DOI: 10.1111/jne.12019] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 12/10/2012] [Accepted: 12/26/2012] [Indexed: 12/16/2022]
Abstract
Food intake activates neurones expressing prolactin-releasing peptide (PrRP) in the medulla oblongata and oxytocin neurones in the hypothalamus. Both PrRP and oxytocin have been shown to have an anorexic action. In the present study, we investigated whether the activation of oxytocin neurones following food intake is mediated by PrRP. We first examined the expression of PrRP receptors (also known as GPR10) in rats. Immunoreactivity of PrRP receptors was observed in oxytocin neurones and in vasopressin neurones in the paraventricular and supraoptic nuclei of the hypothalamus and in the bed nucleus of the stria terminalis. Application of PrRP to isolated supraoptic nuclei facilitated the release of oxytocin and vasopressin. In mice, re-feeding increased the expression of Fos protein in oxytocin neurones of the hypothalamus and bed nucleus of the stria terminalis. The increased expression of Fos protein in oxytocin neurones following re-feeding or i.p. administration of cholecystokinin octapeptide (CCK), a peripheral satiety factor, was impaired in PrRP-deficient mice. CCK-induced oxytocin increase in plasma was also impaired in PrRP-deficient mice. Furthermore, oxytocin receptor-deficient mice showed an increased meal size, as reported in PrRP-deficient mice and in CCKA receptor-deficient mice. These findings suggest that PrRP mediates, at least in part, the activation of oxytocin neurones in response to food intake, and that the CCK-PrRP-oxytocin pathway plays an important role in the control of the termination of each meal.
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Affiliation(s)
- M Yamashita
- Division of Brain and Neurophysiology, Department of Physiology, Jichi Medical University, Shimotsuke-shi, Japan
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Heldsinger A, Lu Y, Zhou SY, Wu X, Grabauskas G, Song I, Owyang C. Cocaine- and amphetamine-regulated transcript is the neurotransmitter regulating the action of cholecystokinin and leptin on short-term satiety in rats. Am J Physiol Gastrointest Liver Physiol 2012; 303:G1042-51. [PMID: 22936273 PMCID: PMC3517666 DOI: 10.1152/ajpgi.00231.2012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Vagal CCK-A receptors (CCKARs) and leptin receptors (LRbs) interact synergistically to mediate short-term satiety. Cocaine- and amphetamine-regulated transcript (CART) peptide is expressed by vagal afferent neurons. We sought to demonstrate that this neurotransmitter regulates CCK and leptin actions on short-term satiety. We also examined the signal transduction pathways responsible for mediating the CART release from the nodose ganglia (NG). ELISA studies coupled with gene silencing of NG neurons by RNA interference elucidated intracellular signaling pathways responsible for CCK/leptin-stimulated CART release. Feeding studies followed by gene silencing of CART in NG established the role of CART in mediating short-term satiety. Immunohistochemistry was performed on rat NG neurons to confirm colocalization of CCKARs and LRbs; 63% of these neurons contained CART. Coadministration of CCK-8 and leptin caused a 2.2-fold increase in CART release that was inhibited by CCK-OPE, a low-affinity CCKAR antagonist. Transfection of cultured NG neurons with steroid receptor coactivator (SRC) or phosphatidylinositol 3-kinase (PI3K) small-interfering RNA (siRNA) or STAT3 lentiviral short hairpin RNA inhibited CCK/leptin-stimulated CART release. Silencing the expression of the EGR-1 gene inhibited the CCK/leptin-stimulated CART release but had no effect on CCK/leptin-stimulated neuronal firing. Electroporation of NG with CART siRNA inhibited CCK/leptin stimulated c-Fos expression in rat hypothalamus. Feeding studies following electroporation of the NG with CART or STAT3 siRNA abolished the effects of CCK/leptin on short-term satiety. We conclude that the synergistic interaction of low-affinity vagal CCKARs and LRbs mediates CART release from the NG, and CART is the principal neurotransmitter mediating short-term satiety. CART release from the NG involves interaction between CCK/SRC/PI3K cascades and leptin/JAK2/PI3K/STAT3 signaling pathways.
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Affiliation(s)
- Andrea Heldsinger
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Yuanxu Lu
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Shi-Yi Zhou
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Xiaoyin Wu
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Gintautas Grabauskas
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Il Song
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Chung Owyang
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
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Harrold JA, Dovey TM, Blundell JE, Halford JC. CNS regulation of appetite. Neuropharmacology 2012; 63:3-17. [DOI: 10.1016/j.neuropharm.2012.01.007] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 01/05/2012] [Accepted: 01/10/2012] [Indexed: 12/14/2022]
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Abstract
PURPOSE OF REVIEW Cholecystokinin (CCK) controls nutrient delivery to the small intestine by inhibiting food intake and gastric emptying. This review deals with recent work shedding new light on how and when. RECENT FINDINGS Intestinal I-cells release CCK in response to dietary lipid and protein through mechanisms involving the G-protein-coupled receptors GPR40 and calcium-sensing receptor. Vagal afferent neurons are a primary target of CCK and are now recognized as an important site of integration of peripheral signals regulating ingestion. In addition to regulating vagal afferent nerve discharge, CCK also controls the expression of receptors and peptide neurotransmitters by these neurons; these actions are potentiated by leptin and inhibited by ghrelin. The responses of vagal afferent neurons to CCK are attenuated in obesity. Studies of human central nervous system responses using functional magnetic resonance imaging indicate activation of brainstem, hypothalamus and motor cortex by ingested fatty acid that is inhibited by a CCK-1 receptor antagonist. CCK may also play a role in adaptive responses in pancreatic islets by maintaining β-cell mass and acting as an incretin in certain circumstances. SUMMARY CCK mediates inhibition of food intake in response to ingested lipid and protein; resistance to CCK occurs in obesity and may contribute to altered mechanisms regulating food intake.
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Affiliation(s)
- Graham J Dockray
- Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
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Stengel A, Taché Y. Interaction between gastric and upper small intestinal hormones in the regulation of hunger and satiety: ghrelin and cholecystokinin take the central stage. Curr Protein Pept Sci 2011; 12:293-304. [PMID: 21428875 PMCID: PMC3670092 DOI: 10.2174/138920311795906673] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Accepted: 03/23/2011] [Indexed: 12/13/2022]
Abstract
Several peptides are produced and released from endocrine cells scattered within the gastric oxyntic and the small intestinal mucosa. These peptide hormones are crucially involved in the regulation of gastrointestinal functions and food intake by conveying their information to central regulatory sites located in the brainstem as well as in the forebrain, such as hypothalamic nuclei. So far, ghrelin is the only known hormone that is peripherally produced in gastric X/A-like cells and centrally acting to stimulate food intake, whereas the suppression of feeding seems to be much more redundantly controlled by a number of gut peptides. Cholecystokinin produced in the duodenum is a well established anorexigenic hormone that interacts with ghrelin to modulate food intake indicating a regulatory network located at the first site of contact with nutrients in the stomach and upper small intestine. In addition, a number of peptides including leptin, urocortin 2, amylin and glucagon-like peptide 1 interact synergistically with CCK to potentiate its satiety signaling effect. New developments have led to the identification of additional peptides in X/A-like cells either derived from the pro-ghrelin gene by alternative splicing and posttranslational processing (obestatin) or a distinct gene (nucleobindin2/nesfatin-1) which have been investigated for their influence on food intake.
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Affiliation(s)
- Andreas Stengel
- Department of Medicine, CURE Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division UCLA, and VA Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Yvette Taché
- Department of Medicine, CURE Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division UCLA, and VA Greater Los Angeles Healthcare System, Los Angeles, CA, USA
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Lembke V, Goebel M, Frommelt L, Inhoff T, Lommel R, Stengel A, Taché Y, Grötzinger C, Bannert N, Wiedenmann B, Klapp BF, Kobelt P. Sulfated cholecystokinin-8 activates phospho-mTOR immunoreactive neurons of the paraventricular nucleus in rats. Peptides 2011; 32:65-70. [PMID: 20933028 PMCID: PMC4040259 DOI: 10.1016/j.peptides.2010.09.025] [Citation(s) in RCA: 11] [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: 08/17/2010] [Revised: 09/28/2010] [Accepted: 09/28/2010] [Indexed: 12/13/2022]
Abstract
The serin/threonin-kinase, mammalian target of rapamycin (mTOR) was detected in the arcuate nucleus (ARC) and paraventricular nucleus of the hypothalamus (PVN) and suggested to play a role in the integration of satiety signals. Since cholecystokinin (CCK) plays a role in the short-term inhibition of food intake and induces c-Fos in PVN neurons, the aim was to determine whether intraperitoneally injected CCK-8S affects the neuronal activity in cells immunoreactive for phospho-mTOR in the PVN. Ad libitum fed male Sprague-Dawley rats received 6 or 10 μg/kg CCK-8S or 0.15M NaCl ip (n=4/group). The number of c-Fos-immunoreactive (ir) neurons was assessed in the PVN, ARC and in the nucleus of the solitary tract (NTS). CCK-8S increased the number of c-Fos-ir neurons in the PVN (6 μg: 103 ± 13 vs. 10 μg: 165 ± 14 neurons/section; p<0.05) compared to vehicle treated rats (4 ± 1, p<0.05), but not in the ARC. CCK-8S also dose-dependently increased the number of c-Fos neurons in the NTS. Staining for phospho-mTOR and c-Fos in the PVN showed a dose-dependent increase of activated phospho-mTOR neurons (17 ± 3 vs. 38 ± 2 neurons/section; p<0.05), while no activated phospho-mTOR neurons were observed in the vehicle group. Triple staining in the PVN showed activation of phospho-mTOR neurons co-localized with oxytocin, corresponding to 9.8 ± 3.6% and 19.5 ± 3.3% of oxytocin neurons respectively. Our observations indicate that peripheral CCK-8S activates phospho-mTOR neurons in the PVN and suggest that phospho-mTOR plays a role in the mediation of CCK-8S's anorexigenic effects.
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Affiliation(s)
- Vanessa Lembke
- Department of Medicine, Division Psychosomatic Medicine and Psychotherapy; Charité, Campus Mitte; Universitätsmedizin Berlin, Germany
| | - Miriam Goebel
- Department of Medicine, Division of Digestive Diseases, CURE Digestive Diseases Research Center and Center for Neurobiology of Stress, UCLA and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Lisa Frommelt
- Department of Medicine, Division Psychosomatic Medicine and Psychotherapy; Charité, Campus Mitte; Universitätsmedizin Berlin, Germany
| | - Tobias Inhoff
- Department of Medicine, Division Hepatology, Gastroenterology, and Endocrinology; Charité, Campus Virchow; Universitätsmedizin Berlin, Germany
| | - Reinhardt Lommel
- Department of Medicine, Division Psychosomatic Medicine and Psychotherapy; Charité, Campus Mitte; Universitätsmedizin Berlin, Germany
| | - Andreas Stengel
- Department of Medicine, Division Psychosomatic Medicine and Psychotherapy; Charité, Campus Mitte; Universitätsmedizin Berlin, Germany
- Department of Medicine, Division of Digestive Diseases, CURE Digestive Diseases Research Center and Center for Neurobiology of Stress, UCLA and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Yvette Taché
- Department of Medicine, Division of Digestive Diseases, CURE Digestive Diseases Research Center and Center for Neurobiology of Stress, UCLA and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Carsten Grötzinger
- Department of Medicine, Division Hepatology, Gastroenterology, and Endocrinology; Charité, Campus Virchow; Universitätsmedizin Berlin, Germany
| | | | - Bertram Wiedenmann
- Department of Medicine, Division Hepatology, Gastroenterology, and Endocrinology; Charité, Campus Virchow; Universitätsmedizin Berlin, Germany
| | - Burghard F. Klapp
- Department of Medicine, Division Psychosomatic Medicine and Psychotherapy; Charité, Campus Mitte; Universitätsmedizin Berlin, Germany
| | - Peter Kobelt
- Department of Medicine, Division Psychosomatic Medicine and Psychotherapy; Charité, Campus Mitte; Universitätsmedizin Berlin, Germany
- Department of Medicine, Division Hepatology, Gastroenterology, and Endocrinology; Charité, Campus Virchow; Universitätsmedizin Berlin, Germany
- Correspondence: Peter Kobelt, PhD Department of Medicine, Division Psychosomatic Medicine and Psychotherapy Charité – Universitätsmedizin Berlin, Campus Mitte Luisenstraße 13 A 10117 Berlin, Germany Phone: +49 30 450-559739 Fax: +49 30 450-559939
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Abstract
Precise automatic control of food intake and energy expenditure maintains a steady weight and is fundamental to survival. The brainstem and hypothalamus are key areas within the brain that integrate peripheral signals from the gut and adipose tissue to control feeding behavior according to energy need. Gut hormones are released after a meal and signal to the brain to initiate meal termination and feelings of satiation. However, reward pathways are able to override this mechanism so that when palatable food is presented, food is consumed irrespective of energy requirements.
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Affiliation(s)
- Katherine A Simpson
- Section of Investigative Medicine, Imperial College London, Commonwealth Building, Du Cane Road, London, W12 0NN, UK
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