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Kerbus RI, Decourt C, Inglis MA, Campbell RE, Anderson GM. Androgen receptor actions on AgRP neurons are not a major cause of reproductive and metabolic impairments in peripubertally androgenized mice. J Neuroendocrinol 2024; 36:e13370. [PMID: 38344844 DOI: 10.1111/jne.13370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 12/22/2023] [Accepted: 01/14/2024] [Indexed: 03/08/2024]
Abstract
Excess levels of circulating androgens during prenatal or peripubertal development are an important cause of polycystic ovary syndrome (PCOS), with the brain being a key target. Approximately half of the women diagnosed with PCOS also experience metabolic syndrome; common features including obesity, insulin resistance and hyperinsulinemia. Although a large amount of clinical and preclinical evidence has confirmed this relationship between androgens and the reproductive and metabolic features of PCOS, the mechanisms by which androgens cause this dysregulation are unknown. Neuron-specific androgen receptor knockout alleviates some PCOS-like features in a peripubertal dihydrotestosterone (DHT) mouse model, but the specific neuronal populations mediating these effects are undefined. A candidate population is the agouti-related peptide (AgRP)-expressing neurons, which are important for both reproductive and metabolic function. We used a well-characterised peripubertal androgenized mouse model and Cre-loxP transgenics to investigate whether deleting androgen receptors specifically from AgRP neurons can alleviate the induced reproductive and metabolic dysregulation. Androgen receptors were co-expressed in 66% of AgRP neurons in control mice, but only in <2% of AgRP neurons in knockout mice. The number of AgRP neurons was not altered by the treatments. Only 20% of androgen receptor knockout mice showed rescue of DHT-induced androgen-induced anovulation and acyclicity. Furthermore, androgen receptor knockout did not rescue metabolic dysfunction (body weight, adiposity or glucose and insulin tolerance). While we cannot rule out developmental compensation in our model, these results suggest peripubertal androgen excess does not markedly influence Agrp expression and does not dysregulate reproductive and metabolic function through direct actions of androgens onto AgRP neurons.
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Affiliation(s)
- Romy I Kerbus
- Centre for Neuroendocrinology and Department of Anatomy, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
| | - Caroline Decourt
- Centre for Neuroendocrinology and Department of Anatomy, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
| | - Megan A Inglis
- Centre for Neuroendocrinology and Department of Anatomy, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
| | - Rebecca E Campbell
- Department of Physiology, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
| | - Greg M Anderson
- Centre for Neuroendocrinology and Department of Anatomy, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
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2
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Min SH, Song DK, Lee CH, Roh E, Kim MS. Hypothalamic AMP-Activated Protein Kinase as a Whole-Body Energy Sensor and Regulator. Endocrinol Metab (Seoul) 2024; 39:1-11. [PMID: 38356211 PMCID: PMC10901667 DOI: 10.3803/enm.2024.1922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 02/16/2024] Open
Abstract
5´-Adenosine monophosphate (AMP)-activated protein kinase (AMPK), a cellular energy sensor, is an essential enzyme that helps cells maintain stable energy levels during metabolic stress. The hypothalamus is pivotal in regulating energy balance within the body. Certain neurons in the hypothalamus are sensitive to fluctuations in food availability and energy stores, triggering adaptive responses to preserve systemic energy equilibrium. AMPK, expressed in these hypothalamic neurons, is instrumental in these regulatory processes. Hypothalamic AMPK activity is modulated by key metabolic hormones. Anorexigenic hormones, including leptin, insulin, and glucagon-like peptide 1, suppress hypothalamic AMPK activity, whereas the hunger hormone ghrelin activates it. These hormonal influences on hypothalamic AMPK activity are central to their roles in controlling food consumption and energy expenditure. Additionally, hypothalamic AMPK activity responds to variations in glucose concentrations. It becomes active during hypoglycemia but is deactivated when glucose is introduced directly into the hypothalamus. These shifts in AMPK activity within hypothalamic neurons are critical for maintaining glucose balance. Considering the vital function of hypothalamic AMPK in the regulation of overall energy and glucose balance, developing chemical agents that target the hypothalamus to modulate AMPK activity presents a promising therapeutic approach for metabolic conditions such as obesity and type 2 diabetes mellitus.
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Affiliation(s)
- Se Hee Min
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Diabetes Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Do Kyeong Song
- Department of Internal Medicine, Ewha Womans University College of Medicine, Seoul, Korea
| | - Chan Hee Lee
- Program of Material Science for Medicine and Pharmaceutics, Hallym University, Chuncheon, Korea
| | - Eun Roh
- Department of Internal Medicine, College of Medicine, Hallym University, Chuncheon, Korea
| | - Min-Seon Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Diabetes Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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3
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Umbayev B, Saliev T, Safarova (Yantsen) Y, Yermekova A, Olzhayev F, Bulanin D, Tsoy A, Askarova S. The Role of Cdc42 in the Insulin and Leptin Pathways Contributing to the Development of Age-Related Obesity. Nutrients 2023; 15:4964. [PMID: 38068822 PMCID: PMC10707920 DOI: 10.3390/nu15234964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/22/2023] [Accepted: 11/26/2023] [Indexed: 12/18/2023] Open
Abstract
Age-related obesity significantly increases the risk of chronic diseases such as type 2 diabetes, cardiovascular diseases, hypertension, and certain cancers. The insulin-leptin axis is crucial in understanding metabolic disturbances associated with age-related obesity. Rho GTPase Cdc42 is a member of the Rho family of GTPases that participates in many cellular processes including, but not limited to, regulation of actin cytoskeleton, vesicle trafficking, cell polarity, morphology, proliferation, motility, and migration. Cdc42 functions as an integral part of regulating insulin secretion and aging. Some novel roles for Cdc42 have also been recently identified in maintaining glucose metabolism, where Cdc42 is involved in controlling blood glucose levels in metabolically active tissues, including skeletal muscle, adipose tissue, pancreas, etc., which puts this protein in line with other critical regulators of glucose metabolism. Importantly, Cdc42 plays a vital role in cellular processes associated with the insulin and leptin signaling pathways, which are integral elements involved in obesity development if misregulated. Additionally, a change in Cdc42 activity may affect senescence, thus contributing to disorders associated with aging. This review explores the complex relationships among age-associated obesity, the insulin-leptin axis, and the Cdc42 signaling pathway. This article sheds light on the vast molecular web that supports metabolic dysregulation in aging people. In addition, it also discusses the potential therapeutic implications of the Cdc42 pathway to mitigate obesity since some new data suggest that inhibition of Cdc42 using antidiabetic drugs or antioxidants may promote weight loss in overweight or obese patients.
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Affiliation(s)
- Bauyrzhan Umbayev
- National Laboratory Astana, Nazarbayev University, Astana 010000, Kazakhstan; (Y.S.); (A.Y.); (F.O.); (A.T.); (S.A.)
| | - Timur Saliev
- S.D. Asfendiyarov Kazakh National Medical University, Almaty 050012, Kazakhstan;
| | - Yuliya Safarova (Yantsen)
- National Laboratory Astana, Nazarbayev University, Astana 010000, Kazakhstan; (Y.S.); (A.Y.); (F.O.); (A.T.); (S.A.)
| | - Aislu Yermekova
- National Laboratory Astana, Nazarbayev University, Astana 010000, Kazakhstan; (Y.S.); (A.Y.); (F.O.); (A.T.); (S.A.)
| | - Farkhad Olzhayev
- National Laboratory Astana, Nazarbayev University, Astana 010000, Kazakhstan; (Y.S.); (A.Y.); (F.O.); (A.T.); (S.A.)
| | - Denis Bulanin
- Department of Biomedical Sciences, School of Medicine, Nazarbayev University, Astana 010000, Kazakhstan;
| | - Andrey Tsoy
- National Laboratory Astana, Nazarbayev University, Astana 010000, Kazakhstan; (Y.S.); (A.Y.); (F.O.); (A.T.); (S.A.)
| | - Sholpan Askarova
- National Laboratory Astana, Nazarbayev University, Astana 010000, Kazakhstan; (Y.S.); (A.Y.); (F.O.); (A.T.); (S.A.)
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4
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Neural regulation of alveolar bone remodeling and periodontal ligament metabolism during orthodontic tooth movement in response to therapeutic loading. J World Fed Orthod 2022; 11:139-145. [DOI: 10.1016/j.ejwf.2022.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 11/24/2022]
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Repetitive transcranial direct current stimulation modulates the brain-gut-microbiome axis in obese rodents. Pharmacol Rep 2022; 74:871-889. [PMID: 35945482 PMCID: PMC9585011 DOI: 10.1007/s43440-022-00401-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/20/2022] [Accepted: 07/26/2022] [Indexed: 11/23/2022]
Abstract
Background Complex interactions between the brain, gut and adipose tissue allow to recognize obesity as a neurometabolic disorder. The recent data have shown that gut microbiota can play a potential role in obesity development. Transcranial direct current stimulation (tDCS) is a safe and non-invasive technique to modulate the activity of cerebral cortex and other connected brain areas also in context of appetite control. The objective of this study was to evaluate the effects of repetitive anodal tDCS (AtDCS) of prefrontal cortex on feeding behavior, metabolic status and selected phyla of gut microbiota in rats with obesity induced by high-calorie diet (HCD). Methods 32 female Wistar rats were equally divided into 4 subgroups depending on diet effect (lean versus obese) and type of stimulation (active versus sham tDCS versus no stimulation). Feed intake, body weight, blood lipoproteins and leptin levels as well as Firmicutes and Bacteroidetes in intestines and stool were examined. Results HCD changed feeding behavior and metabolic parameters typically for obesity-related ranges and resulted in an abundance of Firmicutes at the expanse of Bacteroidetes in the large intestine and stool. AtDCS decreased appetite, body weight, and cholesterol levels. In addition, AtDCS reduced ratio of the average number of Firmicutes to average number of Bacteroidetes in all examined tissues. Conclusions Repetitive AtDCS is not only effective for appetite restriction but can also modulate gut microbiome composition which demonstrates the existence of the brain–gut–microbiome axis and points at this technique as a promising complementary treatment for obesity. However, the effects should be further replicated in human studies.
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Watts AG, Kanoski SE, Sanchez-Watts G, Langhans W. The physiological control of eating: signals, neurons, and networks. Physiol Rev 2022; 102:689-813. [PMID: 34486393 PMCID: PMC8759974 DOI: 10.1152/physrev.00028.2020] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 08/30/2021] [Indexed: 02/07/2023] Open
Abstract
During the past 30 yr, investigating the physiology of eating behaviors has generated a truly vast literature. This is fueled in part by a dramatic increase in obesity and its comorbidities that has coincided with an ever increasing sophistication of genetically based manipulations. These techniques have produced results with a remarkable degree of cell specificity, particularly at the cell signaling level, and have played a lead role in advancing the field. However, putting these findings into a brain-wide context that connects physiological signals and neurons to behavior and somatic physiology requires a thorough consideration of neuronal connections: a field that has also seen an extraordinary technological revolution. Our goal is to present a comprehensive and balanced assessment of how physiological signals associated with energy homeostasis interact at many brain levels to control eating behaviors. A major theme is that these signals engage sets of interacting neural networks throughout the brain that are defined by specific neural connections. We begin by discussing some fundamental concepts, including ones that still engender vigorous debate, that provide the necessary frameworks for understanding how the brain controls meal initiation and termination. These include key word definitions, ATP availability as the pivotal regulated variable in energy homeostasis, neuropeptide signaling, homeostatic and hedonic eating, and meal structure. Within this context, we discuss network models of how key regions in the endbrain (or telencephalon), hypothalamus, hindbrain, medulla, vagus nerve, and spinal cord work together with the gastrointestinal tract to enable the complex motor events that permit animals to eat in diverse situations.
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Affiliation(s)
- Alan G Watts
- The Department of Biological Sciences, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California
| | - Scott E Kanoski
- The Department of Biological Sciences, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California
| | - Graciela Sanchez-Watts
- The Department of Biological Sciences, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, Eidgenössische Technische Hochschule-Zürich, Schwerzenbach, Switzerland
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Mukherjee S, Skrede S, Milbank E, Andriantsitohaina R, López M, Fernø J. Understanding the Effects of Antipsychotics on Appetite Control. Front Nutr 2022; 8:815456. [PMID: 35047549 PMCID: PMC8762106 DOI: 10.3389/fnut.2021.815456] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 12/10/2021] [Indexed: 12/16/2022] Open
Abstract
Antipsychotic drugs (APDs) represent a cornerstone in the treatment of schizophrenia and other psychoses. The effectiveness of the first generation (typical) APDs are hampered by so-called extrapyramidal side effects, and they have gradually been replaced by second (atypical) and third-generation APDs, with less extrapyramidal side effects and, in some cases, improved efficacy. However, the use of many of the current APDs has been limited due to their propensity to stimulate appetite, weight gain, and increased risk for developing type 2 diabetes and cardiovascular disease in this patient group. The mechanisms behind the appetite-stimulating effects of the various APDs are not fully elucidated, partly because their diverse receptor binding profiles may affect different downstream pathways. It is critical to identify the molecular mechanisms underlying drug-induced hyperphagia, both because this may lead to the development of new APDs, with lower appetite-stimulating effects but also because such insight may provide new knowledge about appetite regulation in general. Hence, in this review, we discuss the receptor binding profile of various APDs in relation to the potential mechanisms by which they affect appetite.
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Affiliation(s)
- Sayani Mukherjee
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
| | - Silje Skrede
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Section of Clinical Pharmacology, Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway
| | - Edward Milbank
- NeurObesity Group, Department of Physiology, Center for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición, Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición, Madrid, Spain.,SOPAM, U1063, INSERM, University of Angers, SFR ICAT, Bat IRIS-IBS, Angers, France
| | | | - Miguel López
- NeurObesity Group, Department of Physiology, Center for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición, Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición, Madrid, Spain
| | - Johan Fernø
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
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Quaresma PGF, Wasinski F, Mansano NS, Furigo IC, Teixeira PDS, Gusmao DO, Frazao R, Donato J. Leptin Receptor Expression in GABAergic Cells is Not Sufficient to Normalize Metabolism and Reproduction in Mice. Endocrinology 2021; 162:6353267. [PMID: 34402859 DOI: 10.1210/endocr/bqab168] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Indexed: 12/12/2022]
Abstract
Previous studies indicate that leptin receptor (LepR) expression in GABAergic neurons is necessary for the biological effects of leptin. However, it is not clear whether LepR expression only in GABAergic neurons is sufficient to prevent the metabolic and neuroendocrine imbalances caused by LepR deficiency. In the present study, we produced mice that express the LepR exclusively in GABAergic cells (LepRVGAT mice) and compared them with wild-type (LepR+/+) and LepR-deficient (LepRNull/Null) mice. Although LepRVGAT mice showed a pronounced reduction in body weight and fat mass, as compared with LepRNull/Null mice, male and female LepRVGAT mice exhibited an obese phenotype relative to LepR+/+ mice. Food intake was normalized in LepRVGAT mice; however, LepRVGAT mice still exhibited lower energy expenditure in both sexes and reduced ambulatory activity in the females, compared with LepR+/+ mice. The acute anorexigenic effect of leptin and hedonic feeding were normalized in LepRVGAT mice despite the hyperleptinemia they present. Although LepRVGAT mice showed improved glucose homeostasis compared with LepRNull/Null mice, both male and female LepRVGAT mice exhibited insulin resistance. In contrast, LepR expression only in GABAergic cells was sufficient to normalize the density of agouti-related peptide (AgRP) and α-MSH immunoreactive fibers in the paraventricular nucleus of the hypothalamus. However, LepRVGAT mice exhibited reproductive dysfunctions, including subfertility in males and alterations in the estrous cycle of females. Taken together, our findings indicate that LepR expression in GABAergic cells, although critical to the physiology of leptin, is insufficient to normalize several metabolic aspects and the reproductive function in mice.
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Affiliation(s)
- Paula G F Quaresma
- Universidade de São Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofisica, São Paulo, SP, 05508-000, Brazil
| | - Frederick Wasinski
- Universidade de São Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofisica, São Paulo, SP, 05508-000, Brazil
| | - Naira S Mansano
- Departamento de Anatomia, Instituto de Ciencias Biomedicas, Universidade de São Paulo, São Paulo, SP, 05508-900, Brazil
| | - Isadora C Furigo
- Universidade de São Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofisica, São Paulo, SP, 05508-000, Brazil
| | - Pryscila D S Teixeira
- Universidade de São Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofisica, São Paulo, SP, 05508-000, Brazil
| | - Daniela O Gusmao
- Universidade de São Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofisica, São Paulo, SP, 05508-000, Brazil
| | - Renata Frazao
- Departamento de Anatomia, Instituto de Ciencias Biomedicas, Universidade de São Paulo, São Paulo, SP, 05508-900, Brazil
| | - Jose Donato
- Universidade de São Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofisica, São Paulo, SP, 05508-000, Brazil
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Boucsein A, Kamstra K, Tups A. Central signalling cross-talk between insulin and leptin in glucose and energy homeostasis. J Neuroendocrinol 2021; 33:e12944. [PMID: 33615588 DOI: 10.1111/jne.12944] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 01/10/2021] [Accepted: 01/27/2021] [Indexed: 12/28/2022]
Abstract
Energy homeostasis is controlled by an intricate regulatory system centred in the brain. The peripheral adiposity signals insulin and leptin play a crucial role in this system by informing the brain of the energy status of the body and mediating their catabolic effects through signal transduction in hypothalamic areas that control food intake, energy expenditure and glucose metabolism. Disruptions of insulin and leptin signalling can result in diabetes and obesity. The central signalling cross-talk between insulin and leptin is essential for maintenance of normal healthy energy homeostasis. An important role of leptin in glucoregulation has been revealed. Typically regarded as being controlled by insulin, the control of glucose homeostasis critically depends on functional leptin action. Leptin, on the other hand, is able to lower glucose levels in the absence of insulin, although insulin is necessary for long-term stabilisation of euglycaemia. Evidence from rodent models and human patients suggests that leptin improves insulin sensitivity in type 1 diabetes. The signalling cross-talk between insulin and leptin is likely conveyed by the WNT/β-catenin pathway. Leptin activates WNT/β-catenin signalling, leading to inhibition of glycogen synthase kinase-3β, a key inhibitor of insulin action, thereby facilitating improved insulin signal transduction and sensitisation of insulin action. Interestingly, insights into the roles of insulin and leptin in insects and fish indicate that leptin may have initially evolved as a glucoregulatory hormone and that its anorexigenic and body weight regulatory function was acquired throughout evolution. Furthermore, the regulation of both central and peripheral control of energy homeostasis is tightly controlled by the circadian clock, allowing adaptation of homeostatic processes to environmental cues.
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Affiliation(s)
- Alisa Boucsein
- Centre for Neuroendocrinology, Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Kaj Kamstra
- Centre for Neuroendocrinology, Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Alexander Tups
- Centre for Neuroendocrinology, Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
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10
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Ngo ST, Wang H, Henderson RD, Bowers C, Steyn FJ. Ghrelin as a treatment for amyotrophic lateral sclerosis. J Neuroendocrinol 2021; 33:e12938. [PMID: 33512025 DOI: 10.1111/jne.12938] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 01/04/2021] [Accepted: 01/06/2021] [Indexed: 12/27/2022]
Abstract
Ghrelin is a gut hormone best known for its role in regulating appetite and stimulating the secretion of the anabolic hormone growth hormone (GH). However, there is considerable evidence to show wider-ranging biological actions of ghrelin that favour improvements in cellular and systemic metabolism, as well as neuroprotection. Activation of these ghrelin-mediated pathways may alleviate pathogenic processes that are assumed to contribute to accelerated progression of disease in patients with neurodegenerative disease. Here, we provide a brief overview on the history of discoveries that led to the identification of ghrelin. Focussing on the neurodegenerative disease amyotrophic lateral sclerosis (ALS), we also present an overview of emerging evidence that suggests that ghrelin and ghrelin mimetics may serve as potential therapies for the treatment of ALS. Given that ALS is a highly heterogeneous disease, where multiple disease mechanisms contribute to variability in disease onset and rate of disease progression, we speculate that the wide-ranging biological actions of ghrelin might offer therapeutic benefit through modulating multiple disease-relevant processes observed in ALS. Expanding on the well-known actions of ghrelin in regulating food intake and GH secretion, we consider the potential of ghrelin-mediated pathways in improving body weight regulation, metabolism and the anabolic and neuroprotective actions of GH and insulin-like growth factor-1 (IGF-1). This is of clinical significance because loss of body weight, impairments in systemic and cellular metabolism, and reductions in IGF-1 are associated with faster disease progression and worse disease outcome in patients with ALS.
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Affiliation(s)
- Shyuan T Ngo
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
- Department of Neurology, Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia
- Centre for Clinical Research, The University of Queensland, Brisbane, QLD, Australia
| | - Hao Wang
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Robert D Henderson
- Department of Neurology, Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia
- Centre for Clinical Research, The University of Queensland, Brisbane, QLD, Australia
| | - Cyril Bowers
- Department of Internal Medicine, Tulane University Health Sciences Centre, New Orleans, LA, USA
| | - Frederik J Steyn
- Department of Neurology, Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia
- Centre for Clinical Research, The University of Queensland, Brisbane, QLD, Australia
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
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11
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Bédécarrats GY, Hanlon C, Tsutsui K. Gonadotropin Inhibitory Hormone and Its Receptor: Potential Key to the Integration and Coordination of Metabolic Status and Reproduction. Front Endocrinol (Lausanne) 2021; 12:781543. [PMID: 35095760 PMCID: PMC8792613 DOI: 10.3389/fendo.2021.781543] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/02/2021] [Indexed: 12/18/2022] Open
Abstract
Since its discovery as a novel gonadotropin inhibitory peptide in 2000, the central and peripheral roles played by gonadotropin-inhibiting hormone (GnIH) have been significantly expanded. This is highlighted by the wide distribution of its receptor (GnIH-R) within the brain and throughout multiple peripheral organs and tissues. Furthermore, as GnIH is part of the wider RF-amide peptides family, many orthologues have been characterized across vertebrate species, and due to the promiscuity between ligands and receptors within this family, confusion over the nomenclature and function has arisen. In this review, we intend to first clarify the nomenclature, prevalence, and distribution of the GnIH-Rs, and by reviewing specific localization and ligand availability, we propose an integrative role for GnIH in the coordination of reproductive and metabolic processes. Specifically, we propose that GnIH participates in the central regulation of feed intake while modulating the impact of thyroid hormones and the stress axis to allow active reproduction to proceed depending on the availability of resources. Furthermore, beyond the central nervous system, we also propose a peripheral role for GnIH in the control of glucose and lipid metabolism at the level of the liver, pancreas, and adipose tissue. Taken together, evidence from the literature strongly suggests that, in fact, the inhibitory effect of GnIH on the reproductive axis is based on the integration of environmental cues and internal metabolic status.
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Affiliation(s)
- Grégoy Y. Bédécarrats
- Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada
- *Correspondence: Grégoy Y. Bédécarrats,
| | - Charlene Hanlon
- Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada
| | - Kazuyoshi Tsutsui
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
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12
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Androgen Reduces Mitochondrial Respiration in Mouse Brown Adipocytes: A Model for Disordered Energy Balance in Polycystic Ovary Syndrome. Int J Mol Sci 2020; 22:ijms22010243. [PMID: 33383677 PMCID: PMC7796281 DOI: 10.3390/ijms22010243] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/21/2020] [Accepted: 12/23/2020] [Indexed: 12/15/2022] Open
Abstract
Polycystic ovary syndrome (PCOS) is a common endocrinopathy that is associated with an adverse metabolic profile including reduced postprandial thermogenesis. Although abnormalities in adipose tissue function have been widely reported in women with PCOS, less is known about direct effects of androgen on white and, particularly, brown adipocytes. The purpose of this study was to investigate the effect of the nonaromatizable androgen dihydrotestosterone (DHT) on (1) lipid accumulation and expression of adipogenic markers in immortalized mouse brown adipose cell lines (IMBATs), (2) mitochondrial respiration in IMBATs, (3) mitochondrial DNA content and gene expression, (4) expression of brown adipose tissue (BAT) markers and thermogenic activation. In addition, we profiled the relative levels of 38 adipokines secreted from BAT explants and looked at androgen effects on adipokine gene expression in both IMBATs and immortalized mouse white adipose (IMWATs) cell lines. Androgen treatment inhibited IMBAT differentiation in a dose-dependent manner, reduced markers of adipogenesis, and attenuated the β-adrenoceptor-stimulated increase in uncoupling protein-1 (UCP1) expression. In explants of mouse interscapular BAT, androgen reduced expression of UCP1, peroxisome proliferator-activated receptor-γ coactivator-1 (PCG-1) and Cidea. Significantly, as well as affecting genes involved in thermogenesis in BAT, androgen treatment reduced mitochondrial respiration in IMBATs, as measured by the Seahorse XF method. The results of this study suggest a role for excess androgen in inhibiting brown adipogenesis, attenuating the activation of thermogenesis and reducing mitochondrial respiration in BAT. Together, these data provide a plausible molecular mechanism that may contribute to reduced postprandial thermogenesis and the tendency to obesity in women with PCOS.
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Wang X, Xu J, Kang Q. Neuromodulation of bone: Role of different peptides and their interactions (Review). Mol Med Rep 2020; 23:32. [PMID: 33179112 PMCID: PMC7684869 DOI: 10.3892/mmr.2020.11670] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 09/18/2020] [Indexed: 12/17/2022] Open
Abstract
Our understanding of the skeletal system has been expanded upon the recognition of several neural pathways that serve important roles in bone metabolism and skeletal homeostasis, as bone tissue is richly innervated. Considerable evidence provided by in vitro, animal and human studies have further elucidated the importance of a host of hormones and local factors, including neurotransmitters, in modulating bone metabolism and osteo-chondrogenic differentiation, both peripherally and centrally. Various cells of the musculoskeletal system not only express receptors for these neurotransmitters, but also influence their endogenous levels in the skeleton. As with a number of physiological systems in nature, a neuronal pathway regulating bone turnover will be neutralized by another pathway exerting an opposite effect. These neuropeptides are also critically involved in articular cartilage homeostasis and pathogenesis of degenerative joint disorders, such as osteoarthritis. In the present Review, data on the role of several neuronal populations in nerve-dependent skeletal metabolism is examined, and the molecular events involved are explored, which may reveal broader relationships between two apparently unrelated organs.
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Affiliation(s)
- Xiaoyu Wang
- Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Jia Xu
- Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Qinglin Kang
- Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
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14
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Sergi D, Williams LM. Potential relationship between dietary long-chain saturated fatty acids and hypothalamic dysfunction in obesity. Nutr Rev 2020; 78:261-277. [PMID: 31532491 DOI: 10.1093/nutrit/nuz056] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Diet-induced hypothalamic inflammation, which leads to hypothalamic dysfunction and a loss of regulation of energy balance, is emerging as a potential driver of obesity. Excessive intake of long-chain saturated fatty acids is held to be the causative dietary component in hypothalamic inflammation. This review summarizes current evidence on the role of long-chain saturated fatty acids in promoting hypothalamic inflammation and the related induction of central insulin and leptin insensitivity. Particularly, the present review focuses on the molecular mechanisms linking long-chain saturated fatty acids and hypothalamic inflammation, emphasizing the metabolic fate of fatty acids and the resulting lipotoxicity, which is a key driver of hypothalamic dysfunction. In conclusion, long-chain saturated fatty acids are key nutrients that promote hypothalamic inflammation and dysfunction by fostering the build-up of lipotoxic lipid species, such as ceramide. Furthermore, when long-chain saturated fatty acids are consumed in combination with high levels of refined carbohydrates, the proinflammatory effects are exacerbated via a mechanism that relies on the formation of advanced glycation end products.
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Affiliation(s)
- Domenico Sergi
- Nutrition and Health Substantiation Group, Nutrition and Health Program, Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Adelaide, South Australia, Australia
| | - Lynda M Williams
- Rowett Institute, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
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15
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Zhang L, Reed F, Herzog H. Leptin signalling on arcuate NPY neurones controls adiposity independent of energy balance or diet composition. J Neuroendocrinol 2020; 32:e12898. [PMID: 32885528 DOI: 10.1111/jne.12898] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/29/2020] [Accepted: 07/30/2020] [Indexed: 12/25/2022]
Abstract
Central action of the adipocyte hormone leptin via the neuropeptide Y (NPY) system is considered critical for energy homeostatic control. However, the precise mechanisms for this control are still not clear. To specifically investigate how leptin signalling on the NPY neurone contributes to the control of energy homeostasis, we generated an inducible adult-onset NPY neurone-specific leptin receptor (Lepr) knockout model and performed a comprehensive metabolic phenotyping study. Here, we show that the NPY neurone subpopulation that is directly responsive to leptin is not required for the inhibition of fasting-induced hyperphagia by leptin, although it is essential for the regulation of adiposity independent of changes in energy balance or diet composition. Furthermore, under obesogenic conditions such as a high-fat diet, a lack of Lepr signalling on NPY neurones results in significant increases in food intake and concomitant reductions in energy expenditure, leading to accelerated accumulation of fat mass. Collectively, these findings support the notion that Lepr-expressing NPY neurones act as the key relay point where peripheral adipose storage information is sensed, and corresponding responses are initiated to protect adipose reserves.
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Affiliation(s)
- Lei Zhang
- Neuroscience Division, Garvan Institute of Medical Research, St. Vincent's Hospital, Darlinghurst, NSW, Australia
- St. Vincent's Clinical School, University of NSW, Sydney, NSW, Australia
| | - Felicia Reed
- Neuroscience Division, Garvan Institute of Medical Research, St. Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Herbert Herzog
- Neuroscience Division, Garvan Institute of Medical Research, St. Vincent's Hospital, Darlinghurst, NSW, Australia
- School of Medical Sciences, University of NSW, Sydney, NSW, Australia
- Faculty of Medicine, University of NSW, Sydney, NSW, Australia
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16
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Parker CG, Cheung E. Metabolic control of teleost reproduction by leptin and its complements: Understanding current insights from mammals. Gen Comp Endocrinol 2020; 292:113467. [PMID: 32201232 DOI: 10.1016/j.ygcen.2020.113467] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/05/2020] [Accepted: 03/18/2020] [Indexed: 12/15/2022]
Abstract
Reproduction is expensive. Hence, reproductive physiology is sensitive to an array of endogenous signals that provide information on metabolic and nutritional sufficiency. Although metabolic gating of reproductive function in mammals, as evidenced by studies demonstrating delayed puberty and perturbed fertility, has long been understood to be a function of energy sufficiency, an understanding of the endocrine regulators of this relationship have emerged only within recent decades. Peripheral signals including leptin and cortisol have long been implicated in the physiological integration of metabolism and reproduction. Recent studies have begun to explore possible roles for these two hormones in the regulation of reproduction in teleost fishes, as well as a role for leptin as a catabolic stress hormone. In this review, we briefly explore the reproductive actions of leptin and cortisol in mammals and teleost fishes and possible role of both hormones as putative modulators of the reproductive axis during stress events.
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Affiliation(s)
- Coltan G Parker
- Neuroscience Program, Beckman Institute of Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 N Mathews Ave, Urbana, IL, USA
| | - Eugene Cheung
- Department of Biological Sciences, David Clark Labs, 100 Brooks Avenue, North Carolina State University, Raleigh, NC, USA.
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17
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Neonatal anoxia impairs long‐term energy metabolism and somatic development of Wistar rats. Int J Dev Neurosci 2019; 79:76-85. [DOI: 10.1016/j.ijdevneu.2019.11.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 10/23/2019] [Accepted: 11/06/2019] [Indexed: 01/29/2023] Open
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18
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Lainez NM, Coss D. Obesity, Neuroinflammation, and Reproductive Function. Endocrinology 2019; 160:2719-2736. [PMID: 31513269 PMCID: PMC6806266 DOI: 10.1210/en.2019-00487] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 09/04/2019] [Indexed: 12/13/2022]
Abstract
The increasing occurrence of obesity has become a significant public health concern. Individuals with obesity have higher prevalence of heart disease, stroke, osteoarthritis, diabetes, and reproductive disorders. Reproductive problems include menstrual irregularities, pregnancy complications, and infertility due to anovulation, in women, and lower testosterone and diminished sperm count, in men. In particular, women with obesity have reduced levels of both gonadotropin hormones, and, in obese men, lower testosterone is accompanied by diminished LH. Taken together, these findings indicate central dysregulation of the hypothalamic-pituitary-gonadal axis, specifically at the level of the GnRH neuron function, which is the final brain output for the regulation of reproduction. Obesity is a state of hyperinsulinemia, hyperlipidemia, hyperleptinemia, and chronic inflammation. Herein, we review recent advances in our understanding of how these metabolic and immune changes affect hypothalamic function and regulation of GnRH neurons. In the latter part, we focus on neuroinflammation as a major consequence of obesity and discuss findings that reveal that GnRH neurons are uniquely positioned to respond to inflammatory changes.
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Affiliation(s)
- Nancy M Lainez
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California
| | - Djurdjica Coss
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California
- Correspondence: Djurdjica Coss, PhD, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, 303 SOM Research Building, 900 University Avenue, Riverside, California 92521. E-mail:
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19
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Hou X, Wang Z, Ding F, He Y, Wang P, Liu X, Xu F, Wang J, Yang Y. Taurine Transporter Regulates Adipogenic Differentiation of Human Adipose-Derived Stem Cells through Affecting Wnt/β-catenin Signaling Pathway. Int J Biol Sci 2019; 15:1104-1112. [PMID: 31182929 PMCID: PMC6535786 DOI: 10.7150/ijbs.31794] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 02/16/2019] [Indexed: 11/26/2022] Open
Abstract
Increased adipocytes are associated with obesity and many human disorders including cancers. To further understand the molecular mechanisms of adipogenesis, transcriptome sequencing was performed to find genes involved in the adipogenic differentiation of human adipose-derived stem cells (hASCs). The mRNA of taurine transporter (TauT, also known as SLC6A6) was found significantly upregulated in hASCs undergoing differentiation. TauT expression was also markedly increased in fat tissues from obese mice induced by high fat diet or genetic mutations (ob/ob and db/db mice). In vitro, downregulation of TauT attenuated effectively the adipogenic differentiation of hASCs, and TauT overexpression promoted the formation of adipocytes. Among the molecules transported by TauT, hypotaurine and β-alanine promoted adipocyte formation, whereas taurine inhibited the process. Moreover, the inhibitory effect of TauT knockdown on hASCs differentiation was largely reversed by hypotaurine and β-alanine through promoting the downregulation of β-catenin. These results indicated that TauT regulate adipocyte formation through transported amino acids and may serve as a target for therapeutic intervention of obesity.
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Affiliation(s)
- Xiaodan Hou
- Suzhou Institute of Systems Medicine, Center of Systems Medicine, Chinese Academy of Medical Sciences, Suzhou215123, Jiangsu, China
| | - Zhixue Wang
- Department of Burn and Plastic Surgery, North District of Suzhou Municipal Hospital, Suzhou 215008, Jiangsu, China
| | - Fang Ding
- Suzhou Institute of Systems Medicine, Center of Systems Medicine, Chinese Academy of Medical Sciences, Suzhou215123, Jiangsu, China
| | - Yang He
- Suzhou Institute of Systems Medicine, Center of Systems Medicine, Chinese Academy of Medical Sciences, Suzhou215123, Jiangsu, China
| | - Pengyuan Wang
- Department of Pharmacology, College of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Xia Liu
- Department of Pharmacology, College of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Feng Xu
- Department of Emergency, The First Affiliated Hospital of Soochow University, Suzhou, 215006, Jiangsu Province, China
| | - Jun Wang
- Department of Emergency, The First Affiliated Hospital of Soochow University, Suzhou, 215006, Jiangsu Province, China
| | - Yili Yang
- Suzhou Institute of Systems Medicine, Center of Systems Medicine, Chinese Academy of Medical Sciences, Suzhou215123, Jiangsu, China
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20
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Hou ZS, Tao YX. Mutations in GPR101 as a potential cause of X-linked acrogigantism and acromegaly. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2019; 161:47-67. [DOI: 10.1016/bs.pmbts.2018.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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21
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Huang S, Li Z, Liu Y, Gao D, Zhang X, Hao J, Yang F. Neural regulation of bone remodeling: Identifying novel neural molecules and pathways between brain and bone. J Cell Physiol 2018; 234:5466-5477. [PMID: 29377116 DOI: 10.1002/jcp.26502] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 01/20/2018] [Indexed: 02/05/2023]
Affiliation(s)
- Shishu Huang
- Department of Orthopaedic Surgery West China Hospital, Sichuan University Chengdu China
| | - Zhenxia Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics West China Hospital of Stomatology, Sichuan University Chengdu China
| | - Yunhui Liu
- The Brain Cognition & Brain Disease Institute, Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen China
| | - Dashuang Gao
- The Brain Cognition & Brain Disease Institute, Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen China
| | - Xinzhou Zhang
- Department of Nephrology Shenzhen People's Hospital, Second Clinical Medical College, Jinan University Shenzhen China
| | - Jin Hao
- Program in Biological Sciences in Dental Medicine, Harvard School of Dental Medicine Boston Massachusetts
| | - Fan Yang
- The Brain Cognition & Brain Disease Institute, Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen China
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22
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Wang B, Cheng KKY. Hypothalamic AMPK as a Mediator of Hormonal Regulation of Energy Balance. Int J Mol Sci 2018; 19:ijms19113552. [PMID: 30423881 PMCID: PMC6274700 DOI: 10.3390/ijms19113552] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 11/06/2018] [Accepted: 11/07/2018] [Indexed: 12/13/2022] Open
Abstract
As a cellular energy sensor and regulator, adenosine monophosphate (AMP)-activated protein kinase (AMPK) plays a pivotal role in the regulation of energy homeostasis in both the central nervous system (CNS) and peripheral organs. Activation of hypothalamic AMPK maintains energy balance by inducing appetite to increase food intake and diminishing adaptive thermogenesis in adipose tissues to reduce energy expenditure in response to food deprivation. Numerous metabolic hormones, such as leptin, adiponectin, ghrelin and insulin, exert their energy regulatory effects through hypothalamic AMPK via integration with the neural circuits. Although activation of AMPK in peripheral tissues is able to promote fatty acid oxidation and insulin sensitivity, its chronic activation in the hypothalamus causes obesity by inducing hyperphagia in both humans and rodents. In this review, we discuss the role of hypothalamic AMPK in mediating hormonal regulation of feeding and adaptive thermogenesis, and summarize the diverse underlying mechanisms by which central AMPK maintains energy homeostasis.
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Affiliation(s)
- Baile Wang
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong, China.
- Department of Medicine, The University of Hong Kong, Hong Kong, China.
| | - Kenneth King-Yip Cheng
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, China.
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23
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Speakman JR, Loos RJF, O'Rahilly S, Hirschhorn JN, Allison DB. GWAS for BMI: a treasure trove of fundamental insights into the genetic basis of obesity. Int J Obes (Lond) 2018; 42:1524-1531. [PMID: 29980761 PMCID: PMC6115287 DOI: 10.1038/s41366-018-0147-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 04/10/2018] [Indexed: 01/16/2023]
Abstract
Muller et al. [1] have provided a strong critique of the Genome-Wide Association Studies (GWAS) of body-mass index (BMI), arguing that the GWAS approach for the study of BMI is flawed, and has provided us with few biological insights. They suggest that what is needed instead is a new start, involving GWAS for more complex energy balance related traits. In this invited counter-point, we highlight the substantial advances that have occurred in the obesity field, directly stimulated by the GWAS of BMI. We agree that GWAS for BMI is not perfect, but consider that the best route forward for additional discoveries will likely be to expand the search for common and rare variants linked to BMI and other easily obtained measures of obesity, rather than attempting to perform new, much smaller GWAS for energy balance traits that are complex and expensive to measure. For GWAS in general, we emphasise that the power from increasing the sample size of a crude but easily measured phenotype outweighs the benefits of better phenotyping.
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Affiliation(s)
- J R Speakman
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, UK.
| | - R J F Loos
- The Charles Bronfman Insititute for Personalized Medicine at Mount Sinai, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - S O'Rahilly
- Wellcome Trust-MRC Institute of Metabolic Science,Addenbrookes Treatment, Centre University of Cambridge, Cambridge, CB2 OQQ, UK
| | - J N Hirschhorn
- Division of Endocrinology and Center for Basic and Translational Research, Boston Children's Hospital, Boston, MA, USA
- Broad institute, Cambridge, MA, USA
| | - D B Allison
- School of Public Health, University of Indiana Bloomington, Bloomington, IN, USA
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24
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Zhang N, Bi S. Effects of physical exercise on food intake and body weight: Role of dorsomedial hypothalamic signaling. Physiol Behav 2018; 192:59-63. [DOI: 10.1016/j.physbeh.2018.03.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 03/10/2018] [Accepted: 03/15/2018] [Indexed: 12/19/2022]
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25
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Park JH, Yoo Y, Han J, Park YJ. Altered expression of inflammation-associated genes in the hypothalamus of obesity mouse models. Nutr Res 2018; 70:40-49. [PMID: 30032989 DOI: 10.1016/j.nutres.2018.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 06/13/2018] [Accepted: 06/24/2018] [Indexed: 12/31/2022]
Abstract
Metabolic inflammation is a distinct feature of obesity. Increased inflammation in the adipose tissue and the liver has been so far implicated to affect metabolic homeostasis, mainly insulin resistance. In addition to the peripherals, the inflammation in the hypothalamus which governs systemic metabolism by linking neuronal and endocrine signals has been suggested to be linked to the metabolic disease. However, the underlying molecular mechanisms are poorly understood. We hypothesized that a high-fat diet (HFD) led to central metabolic inflammation via transcriptional changes in the hypothalamus. To address the hypothesis, we characterized obesity-related hypothalamic, transcriptional alterations, and their effects on functional networks. Male C57BL/6J mice were fed with either a control diet (CD) or an HFD for 20 weeks. Microarray and gene ontology analyses of the hypothalamus demonstrated that immune-related pathways, including inflammatory and cytokine signaling, were overrepresented in the hypothalamus of HFD-fed mice compared to that of CD mice. In addition, through secondary analysis of leptin-deficient obese (ob/ob) mouse hypothalamus, we found that enriched gene sets for tumor necrosis factor-α signaling pathways and cancer pathways were common in both the obese mouse models. The results suggest that inflammatory pathway is transcriptionally enriched in the hypothalamus in obesity models and is related with hyperadiposity rather than the primary causes of obesity including the dietary fat and the genetic mutation.
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Affiliation(s)
- Joo Hyun Park
- Department of Nutritional Science and Food Management, Ewha Womans University, Seoul, 03760, Republic of Korea.
| | - Yeongran Yoo
- Department of Nutritional Science and Food Management, Ewha Womans University, Seoul, 03760, Republic of Korea.
| | - Jihee Han
- Department of Nutritional Science and Food Management, Ewha Womans University, Seoul, 03760, Republic of Korea.
| | - Yoon Jung Park
- Department of Nutritional Science and Food Management, Ewha Womans University, Seoul, 03760, Republic of Korea.
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26
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Zhang N, Yang L, Guo L, Bi S. Activation of Dorsomedial Hypothalamic Neurons Promotes Physical Activity and Decreases Food Intake and Body Weight in Zucker Fatty Rats. Front Mol Neurosci 2018; 11:179. [PMID: 29896090 PMCID: PMC5987017 DOI: 10.3389/fnmol.2018.00179] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 05/09/2018] [Indexed: 02/05/2023] Open
Abstract
Previous reports have shown that running wheel activity or voluntary exercise prevents hyperphagia and obesity in various animal models of obesity, but such effects seem only minimal in obese animals lacking leptin or leptin receptors. The mechanisms underlying this ineffectiveness remain unclear. Here, we identified the action of neuronal activation in the dorsomedial hypothalamus (DMH) in modulating physical activity, food intake and body weight using leptin receptor mutant obese Zucker (Lepr(fa), ZF) and Koletsky (Lepr(fak), SHROB) rats. Ad lib-fed SHROB rats with locked running wheels became hyperphagic and gained body weight rapidly. These alterations were not ameliorated in ad lib-fed SHROB rats with voluntary access to running wheels, but the body weight of SHROB rats with running wheel access was significantly decreased when they were pair-fed to the amounts consumed by lean controls. Determinations of hypothalamic gene expression revealed that sedentary ad lib-fed SHROB rats had increased expression of neuropeptide Y (Npy) and decreased expression of pro-opiomelanocortin (Pomc) in the arcuate nucleus (ARC). Both ARC Npy and Pomc expression were further altered under running and pair-fed conditions, indicating that both genes are appropriately regulated in response to increased energy demands or alterations caused by running activity and food restriction. Strikingly, c-Fos immunohistochemistry revealed that while voluntary running activity elevated the number of c-Fos positive cells in the DMH (particularly in the ventral and caudal subregions) of intact rats, such activation was not observed in ZF rats. Using adeno-associated virus (AAV)-mediated expression of the designer receptors hM3D(Gq) in the ventral and caudal DMH of ZF rats, we found that chemogenetic stimulation of neurons in these DMH subregions via injection of the designer drug clozapine N-oxide (CNO) significantly increased their running activity and reduced their food intake and body weight. Together, these results demonstrate that activation of ventral and caudal DMH neurons promotes physical activity and decreases food intake and body weight and suggest that intact DMH neural signaling is likely crucial for exercise-induced reductions of food intake and body weight in obese rats lacking leptin receptors.
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Affiliation(s)
- Ni Zhang
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, United States.,Department of Psychiatry, West China Hospital, Sichuan University, Chengdu, China
| | - Liang Yang
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Lanting Guo
- Department of Psychiatry, West China Hospital, Sichuan University, Chengdu, China
| | - Sheng Bi
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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27
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Abstract
Human obesity has a large genetic component, yet has many serious negative consequences. How this state of affairs has evolved has generated wide debate. The thrifty gene hypothesis was the first attempt to explain obesity as a consequence of adaptive responses to an ancient environment that in modern society become disadvantageous. The idea is that genes (or more precisely, alleles) predisposing to obesity may have been selected for by repeated exposure to famines. However, this idea has many flaws: for instance, selection of the supposed magnitude over the duration of human evolution would fix any thrifty alleles (famines kill the old and young, not the obese) and there is no evidence that hunter-gatherer populations become obese between famines. An alternative idea (called thrifty late) is that selection in famines has only happened since the agricultural revolution. However, this is inconsistent with the absence of strong signatures of selection at single nucleotide polymorphisms linked to obesity. In parallel to discussions about the origin of obesity, there has been much debate regarding the regulation of body weight. There are three basic models: the set-point, settling point and dual-intervention point models. Selection might act against low and high levels of adiposity because food unpredictability and the risk of starvation selects against low adiposity whereas the risk of predation selects against high adiposity. Although evidence for the latter is quite strong, evidence for the former is relatively weak. The release from predation ∼2-million years ago is suggested to have led to the upper intervention point drifting in evolutionary time, leading to the modern distribution of obesity: the drifty gene hypothesis. Recent critiques of the dual-intervention point/drifty gene idea are flawed and inconsistent with known aspects of energy balance physiology. Here, I present a new formulation of the dual-intervention point model. This model includes the novel suggestion that food unpredictability and starvation are insignificant factors driving fat storage, and that the main force driving up fat storage is the risk of disease and the need to survive periods of pathogen-induced anorexia. This model shows why two independent intervention points are more likely to evolve than a single set point. The molecular basis of the lower intervention point is likely based around the leptin pathway signalling. Determining the molecular basis of the upper intervention point is a crucial key target for future obesity research. A potential definitive test to separate the different models is also described.
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Affiliation(s)
- John R Speakman
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China .,Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, UK
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28
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Alsuhaymi N, Habeeballah H, Stebbing MJ, Badoer E. High Fat Diet Decreases Neuronal Activation in the Brain Induced by Resistin and Leptin. Front Physiol 2017; 8:867. [PMID: 29234283 PMCID: PMC5712409 DOI: 10.3389/fphys.2017.00867] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 10/16/2017] [Indexed: 01/09/2023] Open
Abstract
Resistin and leptin are adipokines which act in the brain to regulate metabolic and cardiovascular functions which in some instances are similar, suggesting activation of some common brain pathways. High-fat feeding can reduce the number of activated neurons observed following the central administration of leptin in animals, but the effects on resistin are unknown. The present work compared the distribution of neurons in the brain that are activated by centrally administered resistin, or leptin alone, and, in combination, in rats fed a high fat (HFD) compared to a normal chow diet (ND). Immunohistochemistry for the protein, Fos, was used as a marker of activated neurons. The key findings are (i) following resistin or leptin, either alone or combined, in rats fed the HFD, there were no significant increases in the number of activated neurons in the paraventricular and arcuate nuclei, and in the lateral hypothalamic area (LHA). This contrasted with observations in rats fed a normal chow diet; (ii) in the OVLT and MnPO of HFD rats there were significantly less activated neurons compared to ND following the combined administration of resistin and leptin; (iii) In the PAG, RVMM, and NTS of HFD rats there were significantly less activated neurons compared to ND following resistin. The results suggest that the sensitivity to resistin in the brain was reduced in rats fed a HFD. This has similarities with leptin but there were instances where there was reduced sensitivity to resistin with no significant effects following leptin. This suggests diet influences neuronal effects of resistin.
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Affiliation(s)
- Naif Alsuhaymi
- Neuropharmacology and Neuroinflammation, School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - Hamza Habeeballah
- Neuropharmacology and Neuroinflammation, School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - Martin J Stebbing
- Neuropharmacology and Neuroinflammation, School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - Emilio Badoer
- Neuropharmacology and Neuroinflammation, School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
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Abstract
Although the brain is well established as a master regulator of homeostasis in peripheral tissues, central regulation of bone mass represents a novel and rapidly expanding field of study. This review examines the current understanding of central regulation of the skeleton, exploring several of the key pathways connecting brain to bone and their implications both in mice and the clinical setting. Our understanding of central bone regulation has largely progressed through examination of skeletal responses downstream of nutrient regulatory pathways in the hypothalamus. Mutations and modulation of these pathways, in cases such as leptin deficiency, induce marked bone phenotypes, which have provided vital insights into central bone regulation. These studies have identified several central neuropeptide pathways that stimulate well-defined changes in bone cell activity in response to changes in energy homeostasis. In addition, this work has highlighted the endocrine nature of the skeleton, revealing a complex cross talk that directly regulates other organ systems. Our laboratory has studied bone-active neuropeptide pathways and defined osteoblast-based actions that recapitulate central pathways linking bone, fat, and glucose homeostasis. Studies of neural control of bone have produced paradigm-shifting changes in our understanding of the skeleton and its relationship with the wider array of organ systems.
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Affiliation(s)
- Alexander Corr
- 1 The Division of Bone Biology, Garvan Institute of Medical Research, Sydney, New South Wales, Australia.,2 Faculty of Science, University of Bath, Bath, United Kingdom
| | - James Smith
- 1 The Division of Bone Biology, Garvan Institute of Medical Research, Sydney, New South Wales, Australia.,2 Faculty of Science, University of Bath, Bath, United Kingdom
| | - Paul Baldock
- 1 The Division of Bone Biology, Garvan Institute of Medical Research, Sydney, New South Wales, Australia.,3 Faculty of Medicine, St Vincent's Clinical School, University of New South Wales, Sydney, New South Wales, Australia.,4 School of Medicine Sydney, University of Notre Dame Australia, Sydney, New South Wales, Australia
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Rizwan MZ, Mehlitz S, Grattan DR, Tups A. Temporal and regional onset of leptin resistance in diet-induced obese mice. J Neuroendocrinol 2017; 29. [PMID: 28477438 DOI: 10.1111/jne.12481] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/30/2017] [Accepted: 05/02/2017] [Indexed: 12/01/2022]
Abstract
In common forms of obesity, leptin fails to convey its regulatory effect. This so called "leptin resistance" is not well understood, and solving this puzzle is a key to understanding how obesity develops. In the present study, we investigated the temporal and regional onset of leptin resistance in response to a diet enriched with long-chain saturated fatty acids (high-fat diet; HFD) in mice. Mice were exposed to either a low-fat diet (LFD) or a HFD for 4 hours, 24 hours, 10 days and 28 days. Mice in each group received an i.p. injection of either phosphate-buffered saline or leptin and the number of phosphorylated signal transducer and activator of transcription-3 (pSTAT3) immunoreactive (-IR) cells in the arcuate nucleus (ARC), ventromedial nucleus of the hypothalamus (VMH) and dorsomedial nucleus of the hypothalamus (DMH) was analysed 30 or 120 minutes after treatment. In the ARC, as soon as 24 hours of HFD, the molecular leptin response was reduced by 40% (P≤.01). Compared to at 24 hours, after 10 days, the number of leptin-induced pSTAT3-IR cells was elevated after 120 minutes, suggesting a sustained response and a partial return of leptin sensitivity. After 28 days, leptin failed to induce the number of pSTAT3-IR over control levels, suggesting a markedly reduced sensitivity to leptin. In the VMH after 24 hours, we observed a 50% reduction in leptin-induced pSTAT-3-IR cells, followed by a further decline after 10 days. However, after 28 days, there was a significant increase in pSTAT-3-IR cells (P≤.05), indicating partial recovery of leptin sensitivity. By contrast to these two regions, in the DMH, no loss of leptin sensitivity was observed at any time-point. These findings demonstrate that a loss of sensitivity to leptin occurs rapidly after exposure to HFD in the ARC and VMH but not the DMH. However, there appears to be a biphasic pattern of leptin responsiveness, with a partial return of leptin sensitivity occurring after 10 days in the arcuate nucleus, and after 28 days in the VMH. By 28 days, the response to leptin in the arcuate nucleus was completely lost. These findings suggest that the molecular responses to leptin are altered after high-fat feeding in a time- and region-specific manner.
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Affiliation(s)
- M Z Rizwan
- Department of Physiology, Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
- Department of Anatomy, Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - S Mehlitz
- Department of Physiology, Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
| | - D R Grattan
- Department of Anatomy, Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - A Tups
- Department of Physiology, Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
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Diniz GB, Bittencourt JC. The Melanin-Concentrating Hormone as an Integrative Peptide Driving Motivated Behaviors. Front Syst Neurosci 2017; 11:32. [PMID: 28611599 PMCID: PMC5447028 DOI: 10.3389/fnsys.2017.00032] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 05/04/2017] [Indexed: 12/14/2022] Open
Abstract
The melanin-concentrating hormone (MCH) is an important peptide implicated in the control of motivated behaviors. History, however, made this peptide first known for its participation in the control of skin pigmentation, from which its name derives. In addition to this peripheral role, MCH is strongly implicated in motivated behaviors, such as feeding, drinking, mating and, more recently, maternal behavior. It is suggested that MCH acts as an integrative peptide, converging sensory information and contributing to a general arousal of the organism. In this review, we will discuss the various aspects of energy homeostasis to which MCH has been associated to, focusing on the different inputs that feed the MCH peptidergic system with information regarding the homeostatic status of the organism and the exogenous sensory information that drives this system, as well as the outputs that allow MCH to act over a wide range of homeostatic and behavioral controls, highlighting the available morphological and hodological aspects that underlie these integrative actions. Besides the well-described role of MCH in feeding behavior, a prime example of hypothalamic-mediated integration, we will also examine those functions in which the participation of MCH has not yet been extensively characterized, including sexual, maternal, and defensive behaviors. We also evaluated the available data on the distribution of MCH and its function in the context of animals in their natural environment. Finally, we briefly comment on the evidence for MCH acting as a coordinator between different modalities of motivated behaviors, highlighting the most pressing open questions that are open for investigations and that could provide us with important insights about hypothalamic-dependent homeostatic integration.
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Affiliation(s)
- Giovanne B. Diniz
- Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São PauloSão Paulo, Brazil
| | - Jackson C. Bittencourt
- Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São PauloSão Paulo, Brazil
- Center for Neuroscience and Behavior, Institute of Psychology, University of São PauloSão Paulo, Brazil
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Costanzo PR, Knoblovits P. Male gonadal axis function in patients with type 2 diabetes. Horm Mol Biol Clin Investig 2017; 26:129-34. [PMID: 27071157 DOI: 10.1515/hmbci-2016-0014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 03/08/2016] [Indexed: 11/15/2022]
Abstract
Patients with type 2 diabetes have lower serum testosterone levels and a higher prevalence of hypogonadism than non-diabetic patients, independently of the metabolic control of disease. The mechanisms underlying a decrease in testosterone might be related to age, obesity and insulin resistance, often present in patients with type 2 diabetes. The increase in estrogens due to higher aromatase enzyme activity in increased adipose tissue might exert negative-feedback inhibition centrally. Insulin stimulates gonadal axis activity at all three levels and therefore insulin resistance might account for the lower testosterone production. Leptin exerts a central stimulatory effect but inhibits testicular testosterone secretion. Thus, resistance to leptin in obese subjects with type 2 diabetes determines lower central effects of leptin with lower gonadotropin-releasing hormone (GnRH) secretion and, on the other hand, hyperleptinemia secondary to leptin resistance inhibits testosterone secretion at the testicular level. However, lower testosterone levels in patients with diabetes are observed independently of age, weight and body mass index, which leads to the assumption that hyperglycemia per se might play a role in the decrease in testosterone. Several studies have shown that an overload of glucose results in decreased serum testosterone levels. The aim of this review is to assess changes in the male gonadal axis that occur in patients with type 2 diabetes.
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Beck B, Richy S, Stricker-Krongrad A. Ghrelin and Body Weight Regulation in the Obese Zucker Rat in Relation to Feeding State and Dark/Light Cycle. Exp Biol Med (Maywood) 2016; 228:1124-31. [PMID: 14610250 DOI: 10.1177/153537020322801005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Ghrelin is a new orexigenic peptide primarily produced by the stomach but also present in the hypothalamus. It has adipogenic effects when it is chronically injected in rodents but in obese humans, its plasma concentration is decreased. It can reverse the anorectic effects of leptin when it is co-injected with this peptide in the brain ventricles. The Zucker fa/fa rat is a genetic model of obesity related to a default in the leptin receptor. It is characterized by a large dysregulation of numerous hypothalamic peptides but the ghrelin status of this rat has not yet been determined. Through several experiments, we determine in lean and obese Zucker rats its circulating form in the plasma, its tissue levels and/or expression, and studied the influence of different feeding conditions and its light/dark variations. Ghrelin expression was higher in the obese stomach and hypothalamus (P < 0.05 and P < 0.02, respectively). The ratio of [Octanoyl-Ser3]-ghrelin (active form) to [Des-Octanoyl-Ser3]-ghrelin (inactive form) was approximately 1:1 in the stomach and 2:1 in the plasma in lean and obese rats (no differences). After fasting, plasma ghrelin concentrations increased significantly in lean (+ 64%; P < 0.001) and obese (+ 60%; P < 0.02) rats. After 24 hours of refeeding, they returned to their initial ad lib levels. Ghrelin concentrations were higher in obese rats by 69% (P < 0.005), 65% (P < 0.02), and 73% (P < 0.005) in the ad libitum, fast, and refed states respectively. These results indicate that the obese Zucker rat is characterized by increases in the stomach mRNA expression and in peptide release in the circulation. They clearly support a role for ghrelin in the development of obesity in the absence of leptin signaling.
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Affiliation(s)
- Bernard Beck
- Systèmes Neuromodulateurs des Comportements Ingestifs, Nancy, France.
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Caron A, Richard D. Neuronal systems and circuits involved in the control of food intake and adaptive thermogenesis. Ann N Y Acad Sci 2016; 1391:35-53. [PMID: 27768821 DOI: 10.1111/nyas.13263] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 08/18/2016] [Accepted: 08/24/2016] [Indexed: 12/27/2022]
Abstract
With the still-growing prevalence of obesity worldwide, major efforts are made to understand the various behavioral, environmental, and genetic factors that promote excess fat gain. Obesity results from an imbalance between energy intake and energy expenditure, which emphasizes the importance of deciphering the mechanisms behind energy balance regulation to understand its physiopathology. The control of energy balance is assured by brain systems/circuits capable of generating adequate ingestive and thermogenic responses to maintain the stability of energy reserves, which implies a proper integration of the homeostatic signals that inform about the status of the energy stores. In this article, we overview the organization and functionality of key neuronal circuits or pathways involved in the control of food intake and energy expenditure. We review the role of the corticolimbic (executive and reward) and autonomic systems that integrate their activities to regulate energy balance. We also describe the mechanisms and pathways whereby homeostatic sensing is achieved in response to variations of homeostatic hormones, such as leptin, insulin, and ghrelin, while putting some emphasis on the prominent importance of the mechanistic target of the rapamycin signaling pathway in coordinating the homeostatic sensing process.
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Affiliation(s)
- Alexandre Caron
- Institut Universitaire de Cardiologie et de Pneumologie de Quebec and Faculty of Medicine, Department of Medicine, Université Laval, Quebec City, Quebec, Canada
| | - Denis Richard
- Institut Universitaire de Cardiologie et de Pneumologie de Quebec and Faculty of Medicine, Department of Medicine, Université Laval, Quebec City, Quebec, Canada
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Gomes JR, Freitas JR, Grassiolli S. Effects of Physical Exercise on the Intestinal Mucosa of Rats Submitted to a Hypothalamic Obesity Condition. Anat Rec (Hoboken) 2016; 299:1389-96. [PMID: 27488821 DOI: 10.1002/ar.23453] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 03/17/2016] [Accepted: 03/25/2016] [Indexed: 11/08/2022]
Abstract
The small intestine plays a role in obesity as well as in satiation. However, the effect of physical exercise on the morphology and function of the small intestine during obesity has not been reported to date. This study aimed to evaluate the effects of physical exercise on morphological aspects of the rat small intestine during hypothalamic monosodium glutamate (MSG)-induced obesity. The rats were divided into four groups: Sedentary (S), Monosodium Glutamate (MSG), Exercised (E), and Exercised Monosodium Glutamate (EMSG). The MSG and EMSG groups received a daily injection of monosodium glutamate (4 g/kg) during the 5 first days after birth. The S and E groups were considered as control groups and received injections of saline. At weaning, at 21 days after birth, the EMSG and E groups were submitted to swimming practice 3 times a week until the 90th day, when all groups were sacrificed and the parameters studied recorded. Exercise significantly reduced fat deposits and the Lee Index in MSG-treated animals, and also reduced the thickness of the intestinal wall, the number of goblet cells and intestinal alkaline phosphatase activity. However, physical activity alone increased the thickness and height of villi, and the depth of the crypts. In conclusion, regular physical exercise may alter the morphology or/and functions of the small intestine, reducing the prejudicial effects of hypothalamic obesity. Anat Rec, 299:1389-1396, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- J R Gomes
- Departamento de Biologia Estrutural Molecular e Genetica, Universidade Estadual de Ponta Grossa, Ponta Grossa, PR, Brasil, Avenida Carlos Cavalcanti, 4748, Ponta Grossa, PR, CEP 84030-900, Brazil.
| | - J R Freitas
- Departamento de Biologia Estrutural Molecular e Genetica, Universidade Estadual de Ponta Grossa, Ponta Grossa, PR, Brasil, Avenida Carlos Cavalcanti, 4748, Ponta Grossa, PR, CEP 84030-900, Brazil
| | - S Grassiolli
- Centro de Ciências Biológicas e da Saúde, Universidade Estadual do Oeste do Paraná -Campus de Cascavel, Rua Universitária, 2069, Bairro: Jardim Universitário, CEP 85819-110, Cascavel, PR, Brazil
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Hypothalamic AMPK as a Regulator of Energy Homeostasis. Neural Plast 2016; 2016:2754078. [PMID: 27547453 PMCID: PMC4980534 DOI: 10.1155/2016/2754078] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 07/10/2016] [Indexed: 12/16/2022] Open
Abstract
Activated in energy depletion conditions, AMP-activated protein kinase (AMPK) acts as a cellular energy sensor and regulator in both central nervous system and peripheral organs. Hypothalamic AMPK restores energy balance by promoting feeding behavior to increase energy intake, increasing glucose production, and reducing thermogenesis to decrease energy output. Besides energy state, many hormones have been shown to act in concert with AMPK to mediate their anorexigenic and orexigenic central effects as well as thermogenic influences. Here we explore the factors that affect hypothalamic AMPK activity and give the underlying mechanisms for the role of central AMPK in energy homeostasis together with the physiological effects of hypothalamic AMPK on energy balance restoration.
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Habeeballah H, Alsuhaymi N, Stebbing MJ, Jenkins TA, Badoer E. Central leptin and resistin combined elicit enhanced central effects on renal sympathetic nerve activity. Exp Physiol 2016; 101:791-800. [PMID: 27151838 DOI: 10.1113/ep085723] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 05/03/2016] [Indexed: 01/03/2023]
Abstract
NEW FINDINGS What is the central question of this study? Leptin and resistin act centrally to increase renal sympathetic nerve activity (RSNA). We investigated whether a combination of resistin and leptin could induce a greater response than either alone. We also used Fos protein to quantify the number of activated neurons in the brain. What is the main finding and its importance? A combination of leptin and resistin induced a greater increase in RSNA than either hormone alone. This was correlated with a greater number of activated neurons in the arcuate nucleus than with either hormone alone. Leptin and resistin act centrally to increase renal sympathetic nerve activity (RSNA). We investigated whether a combination of resistin and leptin could induce a greater response than either alone. Mean arterial pressure, heart rate and RSNA were recorded before and for 3 h after intracerebroventricular saline (control; n = 5), leptin (7 μg; n = 5), resistin (7 μg; n = 4) and leptin administered 15 min after resistin (n = 6). Leptin alone and resistin alone significantly increased RSNA (74 ± 17 and 50 ± 14%, respectively; P < 0.0001 compared with saline). When leptin and resistin were combined, there was a significantly greater increase in RSNA (163 ± 23%) compared with either hormone alone (P < 0.0001). Maximal responses of mean arterial pressure and heart rate were not significantly different between groups. We also used Fos protein to quantify the number of activated neurons in the brain. Compared with controls, there were significant increases in numbers of Fos-positive neurons in the arcuate and hypothalamic paraventricular nuclei when leptin or resistin was administered alone or when they were combined, and in the lamina terminalis when leptin and resistin were combined. Only in the arcuate nucleus was the increase significantly greater compared with either hormone alone. The findings show that a combination of leptin and resistin induces a greater RSNA increase and a greater number of activated neurons in the arcuate nucleus than with either hormone alone. Given that leptin makes an important contribution to the elevated RSNA observed in obese and overweight conditions, the increased concentrations of leptin and resistin may mean that the contribution of leptin to the elevated RSNA in those conditions is enhanced.
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Affiliation(s)
- Hamza Habeeballah
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Naif Alsuhaymi
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Martin J Stebbing
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Trisha A Jenkins
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Emilio Badoer
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
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Escobar S, Rocha A, Felip A, Carrillo M, Zanuy S, Kah O, Servili A. Leptin receptor gene in the European sea bass (Dicentrarchus labrax): Cloning, phylogeny, tissue distribution and neuroanatomical organization. Gen Comp Endocrinol 2016; 229:100-11. [PMID: 26979276 DOI: 10.1016/j.ygcen.2016.03.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 03/07/2016] [Accepted: 03/11/2016] [Indexed: 11/25/2022]
Abstract
In this study, we report the cloning of three transcripts for leptin receptor in the European sea bass, a marine teleost of economic interest. The two shortest variants, generated by different splice sites, encode all functional extracellular and intracellular domains but missed the transmembrane domain. The resulting proteins are therefore potential soluble binding proteins for leptin. The longest transcript (3605bp), termed sblepr, includes all the essential domains for binding and transduction of the signal. Thus, it is proposed as the ortholog for the human LEPR gene, the main responsible for leptin signaling. Phylogenetic analysis shows the sblepr clustered within the teleost leptin receptor group in 100% of the bootstrap replicates. The neuroanatomical localization of sblepr expressing cells has been assessed by in situ hybridization in brains of sea bass of both sexes during their first sexual maturation. At histological level, the distribution pattern of sblepr expressing cells in the brain shows no clear differences regarding sex or reproductive season. Transcripts of the sblepr have a widespread distribution throughout the forebrain and midbrain until the caudal portion of the hypothalamus. A high hybridization signal is detected in the telencephalon, preoptic area, medial basal and caudal hypothalamus and in the pituitary gland. In a more caudal region, sblepr expressing cells are identified in the longitudinal torus. The expression pattern observed for sblepr suggests that in sea bass, leptin is very likely to be involved in the control of food intake, energy reserves and reproduction.
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Affiliation(s)
- Sebastián Escobar
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre la Sal (CSIC), Ribera de Cabanes s/n, 12595 Torre la Sal, Castellón, Spain
| | - Ana Rocha
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre la Sal (CSIC), Ribera de Cabanes s/n, 12595 Torre la Sal, Castellón, Spain
| | - Alicia Felip
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre la Sal (CSIC), Ribera de Cabanes s/n, 12595 Torre la Sal, Castellón, Spain
| | - Manuel Carrillo
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre la Sal (CSIC), Ribera de Cabanes s/n, 12595 Torre la Sal, Castellón, Spain
| | - Silvia Zanuy
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre la Sal (CSIC), Ribera de Cabanes s/n, 12595 Torre la Sal, Castellón, Spain.
| | - Olivier Kah
- Team NEED, Research Institute for Health, Environment and Occupation, INSERM U1085, SFR Biosit, Université de Rennes 1, France.
| | - Arianna Servili
- Team NEED, Research Institute for Health, Environment and Occupation, INSERM U1085, SFR Biosit, Université de Rennes 1, France
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Mutations in Melanocortin-3 Receptor Gene and Human Obesity. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 140:97-129. [DOI: 10.1016/bs.pmbts.2016.01.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Chen T, Chen S, Ren C, Hu C, Tang D, Yan A. Two isoforms of leptin in the White-clouds Mountain minnow (Tanichthys albonubes): Differential regulation by estrogen despite similar response to fasting. Gen Comp Endocrinol 2016; 225:174-184. [PMID: 26386182 DOI: 10.1016/j.ygcen.2015.08.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 07/28/2015] [Accepted: 08/01/2015] [Indexed: 01/03/2023]
Abstract
Leptin has been well-established as a canonical anorexic peptide hormone in mammals, though much of its function in fish remains obscure. In this study, the cDNAs of two leptin isoforms (leptin-A and leptin-B) were cloned from the liver of a small cyprinid fish, Tanichthys albonubes. The two T. albonubes leptins, sharing low primary amino acid sequence homology with their mammalian counterparts, and between themselves, are highly conserved in three-dimensional protein structures and gene structures. Liver is a major source of leptin mRNA in T. albonubes with leptin-A being the dominant form. The expression of hepatic leptin-A but not leptin-B mRNA in female fish is significantly higher than in male fish. Transcriptional hepatic levels of leptin-A and leptin-B in both male and female fish were demonstrated to increase after long-term fasting (10-25days) but decline upon re-feeding (3days). Strikingly, estrogen (E2) administration induced only leptin-A but not leptin-B hepatic mRNA expression in both male and female fish. Our study here provides the first evidence for differential regulation of two leptins in fish, and sheds new light on the possible origin of leptin in lower vertebrates.
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Affiliation(s)
- Ting Chen
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Guangzhou, China.
| | - Shuang Chen
- Department of Anatomy, University of Hong Kong, Hong Kong, China.
| | - Chunhua Ren
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Guangzhou, China.
| | - Chaoqun Hu
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Guangzhou, China.
| | | | - Aifen Yan
- College of Medicine, Foshan University, Foshan, China.
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Houweling P, Kulkarni RN, Baldock PA. Neuronal control of bone and muscle. Bone 2015; 80:95-100. [PMID: 26453499 DOI: 10.1016/j.bone.2015.05.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 04/27/2015] [Accepted: 05/04/2015] [Indexed: 12/30/2022]
Abstract
The functional interplay between bone and muscle that enables locomotion is a fundamental aspect of daily life. However, other interactions between bone and muscle continue to attract attention as our understanding of the breath and importance of this inter-relationship continues to expand. Of particular interest is the regulatory connection between bone and muscle, which adds a new insight to the coordination of the bone/muscle unit. We have appreciated the importance of neuronal signaling to the control of bone turnover and muscle contraction, but recent data indicate that neuronal inputs control a far wider range of bone and muscle physiology than previously appreciated. This review outlines the role of the sympathetic nervous system and neuronal/neuropeptide inputs upon the regulation of bone and muscle tissue, and the potential for co-regulatory actions, particularly involving the sympathetic nervous system. This article is part of a Special Issue entitled "Muscle Bone Interactions".
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Affiliation(s)
- Peter Houweling
- Murdoch Childrens Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia; Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, VIC, Australia
| | - Rishikesh N Kulkarni
- Osteoporosis and Bone Biology Division, Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, NSW, Australia
| | - Paul A Baldock
- Osteoporosis and Bone Biology Division, Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, NSW, Australia; Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia; School of Medicine, The University of Notre Dame Australia, Sydney, NSW, Australia.
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43
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Yoshimura M, Uezono Y, Ueta Y. Anorexia in human and experimental animal models: physiological aspects related to neuropeptides. J Physiol Sci 2015; 65:385-95. [PMID: 26123258 PMCID: PMC10717229 DOI: 10.1007/s12576-015-0386-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/16/2015] [Indexed: 01/20/2023]
Abstract
Anorexia, a loss of appetite for food, can be caused by various physiological and pathophysiological conditions. In this review, firstly, clinical aspects of anorexia nervosa are summarized in brief. Secondly, hypothalamic neuropeptides responsible for feeding regulation in each hypothalamic nucleus are discussed. Finally, three different types of anorexigenic animal models; dehydration-induced anorexia, cisplatin-induced anorexia and cancer anorexia-cachexia, are introduced. In conclusion, hypothalamic neuropeptides may give us novel insight to understand and find effective therapeutics strategy essential for various kinds of anorexia.
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Affiliation(s)
- Mitsuhiro Yoshimura
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, 807-8555 Japan
| | - Yasuhito Uezono
- Division of Cancer Pathophysiology, National Cancer Center Research Institute, Tokyo, 104-0045 Japan
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, 807-8555 Japan
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Matsuzaki T, Iwasa T, Tungalagsuvd A, Munkhzaya M, Kawami T, Yamasaki M, Murakami M, Kato T, Kuwahara A, Yasui T, Irahara M. The responses of hypothalamic NPY and OBRb mRNA expression to food deprivation develop during the neonatal-prepubertal period and exhibit gender differences in rats. Int J Dev Neurosci 2015; 41:63-7. [PMID: 25561025 DOI: 10.1016/j.ijdevneu.2014.11.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 11/15/2014] [Accepted: 11/15/2014] [Indexed: 11/24/2022] Open
Abstract
Neuropeptide Y (NPY) is an important hypothalamic orexigenic neuropeptide that acts in the brain. It has been established that the fasting-induced up-regulation of NPY expression is mainly caused by a reduction in the activity of leptin, which is a hormone secreted by adipose tissue. We have reported that in female rats hypothalamic NPY mRNA expression does not respond to fasting during the early neonatal period, but subsequently becomes sensitive to it later in the neonatal period. In this study, we compared the developmental changes in the responses of NPY and leptin expression to fasting between male and female rats during the neonatal to pre-pubertal period. Fasting was induced by maternal deprivation during the pre-weaning period (postnatal days 10 and 20) and by food deprivation during the post-weaning period (postnatal day 30). Hypothalamic NPY mRNA expression was not affected by fasting on postnatal day 10, whereas it was increased by fasting on postnatal day 20 and 30 in both males and females. On the other hand, the serum leptin level was decreased by fasting at all examined ages in both sexes. Namely, hypothalamic NPY mRNA expression was not correlated with the reduction in the serum leptin level at postnatal day 10 in either sex. Under the fasted conditions, the hypothalamic NPY mRNA levels of the males were higher than those of the females on postnatal days 20 and 30, whereas no such differences were observed under the normal nourishment conditions. The serum leptin levels observed under the fasted conditions did not differ between males and females at any examined age. These results suggest that some hypothalamic NPY functions develop during the neonatal period and that there is no major difference between the sexes with regard to the time when NPY neurons become sensitive to fasting. They also indicate that hypothalamic NPY expression is more sensitive to under-nutrition in male rats than in female rats, at least during the pre-pubertal period.
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Affiliation(s)
- Toshiya Matsuzaki
- Department of Obstetrics and Gynecology, The University of Tokushima Graduate School, Institute of Health Biosciences, 3-18-15 Kuramoto-Cho, Tokushima 770-8503, Japan.
| | - Takeshi Iwasa
- Department of Obstetrics and Gynecology, The University of Tokushima Graduate School, Institute of Health Biosciences, 3-18-15 Kuramoto-Cho, Tokushima 770-8503, Japan
| | - Altankhuu Tungalagsuvd
- Department of Obstetrics and Gynecology, The University of Tokushima Graduate School, Institute of Health Biosciences, 3-18-15 Kuramoto-Cho, Tokushima 770-8503, Japan
| | - Munkhsaikhan Munkhzaya
- Department of Obstetrics and Gynecology, The University of Tokushima Graduate School, Institute of Health Biosciences, 3-18-15 Kuramoto-Cho, Tokushima 770-8503, Japan
| | - Takako Kawami
- Department of Obstetrics and Gynecology, The University of Tokushima Graduate School, Institute of Health Biosciences, 3-18-15 Kuramoto-Cho, Tokushima 770-8503, Japan
| | - Mikio Yamasaki
- Department of Obstetrics and Gynecology, The University of Tokushima Graduate School, Institute of Health Biosciences, 3-18-15 Kuramoto-Cho, Tokushima 770-8503, Japan
| | - Masahiro Murakami
- Department of Obstetrics and Gynecology, Shikoku Medical Center for Children and Adults, Senyu-cho 2-1-1, Zentsuji City, Kagawa 765-8507, Japan
| | - Takeshi Kato
- Department of Obstetrics and Gynecology, The University of Tokushima Graduate School, Institute of Health Biosciences, 3-18-15 Kuramoto-Cho, Tokushima 770-8503, Japan
| | - Akira Kuwahara
- Department of Obstetrics and Gynecology, The University of Tokushima Graduate School, Institute of Health Biosciences, 3-18-15 Kuramoto-Cho, Tokushima 770-8503, Japan
| | - Toshiyuki Yasui
- Department of Reproductive Technology, Institute of Health Biosciences, The University of Tokushima Graduate School, Japan
| | - Minoru Irahara
- Department of Obstetrics and Gynecology, The University of Tokushima Graduate School, Institute of Health Biosciences, 3-18-15 Kuramoto-Cho, Tokushima 770-8503, Japan
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Wellhauser L, Gojska NM, Belsham DD. Delineating the regulation of energy homeostasis using hypothalamic cell models. Front Neuroendocrinol 2015; 36:130-49. [PMID: 25223866 DOI: 10.1016/j.yfrne.2014.09.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 08/28/2014] [Accepted: 09/02/2014] [Indexed: 12/27/2022]
Abstract
Attesting to its intimate peripheral connections, hypothalamic neurons integrate nutritional and hormonal cues to effectively manage energy homeostasis according to the overall status of the system. Extensive progress in the identification of essential transcriptional and post-translational mechanisms regulating the controlled expression and actions of hypothalamic neuropeptides has been identified through the use of animal and cell models. This review will introduce the basic techniques of hypothalamic investigation both in vivo and in vitro and will briefly highlight the key advantages and challenges of their use. Further emphasis will be place on the use of immortalized models of hypothalamic neurons for in vitro study of feeding regulation, with a particular focus on cell lines proving themselves most fruitful in deciphering fundamental basics of NPY/AgRP, Proglucagon, and POMC neuropeptide function.
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Affiliation(s)
- Leigh Wellhauser
- Department of Physiology, University of Toronto, Toronto, Ontario M5G 1A8, Canada
| | - Nicole M Gojska
- Department of Physiology, University of Toronto, Toronto, Ontario M5G 1A8, Canada
| | - Denise D Belsham
- Departments of Physiology, Medicine and OB/GYN, University of Toronto, Toronto, Ontario M5G 1A8, Canada; Division of Cellular and Molecular Biology, Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5S 1A8, Canada.
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Bouret S, Levin BE, Ozanne SE. Gene-environment interactions controlling energy and glucose homeostasis and the developmental origins of obesity. Physiol Rev 2015; 95:47-82. [PMID: 25540138 PMCID: PMC4281588 DOI: 10.1152/physrev.00007.2014] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Obesity and type 2 diabetes mellitus (T2DM) often occur together and affect a growing number of individuals in both the developed and developing worlds. Both are associated with a number of other serious illnesses that lead to increased rates of mortality. There is likely a polygenic mode of inheritance underlying both disorders, but it has become increasingly clear that the pre- and postnatal environments play critical roles in pushing predisposed individuals over the edge into a disease state. This review focuses on the many genetic and environmental variables that interact to cause predisposed individuals to become obese and diabetic. The brain and its interactions with the external and internal environment are a major focus given the prominent role these interactions play in the regulation of energy and glucose homeostasis in health and disease.
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Affiliation(s)
- Sebastien Bouret
- The Saban Research Institute, Neuroscience Program, Childrens Hospital Los Angeles, University of Southern California, Los Angeles, California; Inserm U837, Jean-Pierre Aubert Research Center, University Lille 2, Lille, France; Neurology Service, Veterans Administration Medical Center, East Orange, New Jersey; Department of Neurology and Neurosciences, Rutgers, New Jersey Medical School, Newark, New Jersey; and University of Cambridge Institute of Metabolic Science and MRC Metabolic Diseases Unit, Cambridge, United Kingdom
| | - Barry E Levin
- The Saban Research Institute, Neuroscience Program, Childrens Hospital Los Angeles, University of Southern California, Los Angeles, California; Inserm U837, Jean-Pierre Aubert Research Center, University Lille 2, Lille, France; Neurology Service, Veterans Administration Medical Center, East Orange, New Jersey; Department of Neurology and Neurosciences, Rutgers, New Jersey Medical School, Newark, New Jersey; and University of Cambridge Institute of Metabolic Science and MRC Metabolic Diseases Unit, Cambridge, United Kingdom
| | - Susan E Ozanne
- The Saban Research Institute, Neuroscience Program, Childrens Hospital Los Angeles, University of Southern California, Los Angeles, California; Inserm U837, Jean-Pierre Aubert Research Center, University Lille 2, Lille, France; Neurology Service, Veterans Administration Medical Center, East Orange, New Jersey; Department of Neurology and Neurosciences, Rutgers, New Jersey Medical School, Newark, New Jersey; and University of Cambridge Institute of Metabolic Science and MRC Metabolic Diseases Unit, Cambridge, United Kingdom
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Wada N, Hirako S, Takenoya F, Kageyama H, Okabe M, Shioda S. Leptin and its receptors. J Chem Neuroanat 2014; 61-62:191-9. [PMID: 25218975 DOI: 10.1016/j.jchemneu.2014.09.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 09/02/2014] [Accepted: 09/03/2014] [Indexed: 12/11/2022]
Abstract
Leptin is mainly produced in the white adipose tissue before being secreted into the blood and transported across the blood-brain barrier. Leptin binds to a specific receptor (LepR) that has numerous subtypes (LepRa, LepRb, LepRc, LepRd, LepRe, and LepRf). LepRb, in particular, is expressed in several brain nuclei, including the arcuate nucleus, the paraventricular nucleus, and the dorsomedial, lateral and ventromedial regions of the hypothalamus. LepRb is also co-expressed with several neuropeptides, including proopiomelanocortin, neuropeptide Y, galanin, galanin-like peptide, gonadotropin-releasing hormone, tyrosine hydroxylase and neuropeptide W. Functionally, LepRb induces activation of the JAK2/ERK, /STAT3, /STAT5 and IRS/PI3 kinase signaling cascades, which are important for the regulation of energy homeostasis and appetite in mammals. In this review, we discuss the structure, genetics and distribution of the leptin receptors, and their role in cell signaling mechanisms.
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Affiliation(s)
- Nobuhiro Wada
- Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai Shinagawa-ku, Tokyo 142-8555, Japan
| | - Satoshi Hirako
- Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai Shinagawa-ku, Tokyo 142-8555, Japan
| | - Fumiko Takenoya
- Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai Shinagawa-ku, Tokyo 142-8555, Japan; Department of Physical Education, Hoshi University School of Pharmacy and Pharmaceutical Science, Tokyo 142-8501, Japan
| | - Haruaki Kageyama
- Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai Shinagawa-ku, Tokyo 142-8555, Japan; Department of Nutrition, Faculty of Health Care, Kiryu University, 606-7 Kasakakecho Azami, Midori City 379-2392, Gunma, Japan
| | - Mai Okabe
- Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai Shinagawa-ku, Tokyo 142-8555, Japan; Tokyo Shokuryo Dietitian Academy, Tokyo 154-0001, Japan
| | - Seiji Shioda
- Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai Shinagawa-ku, Tokyo 142-8555, Japan.
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Herrid M, Palanisamy SKA, Ciller UA, Fan R, Moens P, Smart NA, McFarlane JR. An updated view of leptin on implantation and pregnancy: a review. Physiol Res 2014; 63:543-57. [PMID: 24908087 DOI: 10.33549/physiolres.932674] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The hormone leptin, which is thought to be primarily produced by adipose tissue, is a polypeptide that was initially characterized by its ability to regulate food intake and energy metabolism. Leptin appears to signal the status of body energy stores to the brain, resulting in the regulation of food intake and whole-body energy expenditure. Subsequently, it was recognized as a cytokine with a wide range of peripheral actions and is involved in the regulation of a number of physiological systems including reproduction. In the fed state, leptin circulates in the plasma in proportion to body adiposity in all species studied to date. However other factors such as sex, age, body mass index (BMI), sex steroids and pregnancy may also affect leptin levels in plasma. In pregnant mice and humans, the placenta is also a major site of leptin expression. Leptin circulates in biological fluids both as free protein and in a form that is bound to the soluble isoform of its receptor or other binding proteins such as one of the immunoglobulin superfamily members Siglec-6 (OB-BP1). Although the actions of leptin in the control of reproductive function are thought to be exerted mainly via the hypothalamic-pituitary-gonadal axis, there have also been reports of local direct effects of leptin at the peripheral level, however, these data appear contradictory. Therefore, there is a need to summarize the current status of research outcomes and analyze the possible reasons for differing results and thus provide researchers with new insight in designing experiments to investigate leptin effect on reproduction. Most importantly, our recent experimental data suggesting that reproductive performance is improved by decreasing concentrations of peripheral leptin was unexpected and cannot be explained by hypotheses drawn from the experiments of excessive exogenous leptin administration to normal animals or ob/ob mice.
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Affiliation(s)
- M Herrid
- University of New England, Armidale, Australia.
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Nestor CC, Kelly MJ, Rønnekleiv OK. Cross-talk between reproduction and energy homeostasis: central impact of estrogens, leptin and kisspeptin signaling. Horm Mol Biol Clin Investig 2014; 17:109-28. [PMID: 25372735 PMCID: PMC4959432 DOI: 10.1515/hmbci-2013-0050] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 10/07/2013] [Indexed: 02/06/2023]
Abstract
The central nervous system receives hormonal cues (e.g., estrogens and leptin, among others) that influence reproduction and energy homeostasis. 17β-estradiol (E2) is known to regulate gonadotropin-releasing hormone (GnRH) secretion via classical steroid signaling and rapid non-classical membrane-initiated signaling. Because GnRH neurons are void of leptin receptors, the actions of leptin on these neurons must be indirect. Although it is clear that the arcuate nucleus of the hypothalamus is the primary site of overlap between these two systems, it is still unclear which neural network(s) participate in the cross-talk of E2 and leptin, two hormones essential for reproductive function and metabolism. Herein we review the progress made in understanding the interactions between reproduction and energy homeostasis by focusing on the advances made to understand the cellular signaling of E2 and leptin on three neural networks: kisspeptin, pro-opiomelanocortin (POMC) and neuropeptide Y (NPY). Although critical in mediating the actions of E2 and leptin, considerable work still remains to uncover how these neural networks interact in vivo.
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Affiliation(s)
- Casey C Nestor
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR, USA
| | - Martin J. Kelly
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR, USA; and Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA
| | - Oline K. Rønnekleiv
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR, USA; and Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA
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50
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Di Yorio MP, Bilbao MG, Faletti AG. Neuropeptide Y regulates the leptin receptors in rat hypothalamic and pituitary explant cultures. ACTA ACUST UNITED AC 2014; 188:13-20. [DOI: 10.1016/j.regpep.2013.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 11/05/2013] [Accepted: 11/19/2013] [Indexed: 01/01/2023]
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