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Papadakis S, Thompson JR, Feczko E, Miranda-Dominguez O, Dunn GA, Selby M, Mitchell AJ, Sullivan EL, Fair DA. Perinatal Western-style diet exposure associated with decreased microglial counts throughout the arcuate nucleus of the hypothalamus in Japanese macaques. J Neurophysiol 2024; 131:241-260. [PMID: 38197176 PMCID: PMC11286309 DOI: 10.1152/jn.00213.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 12/13/2023] [Accepted: 01/03/2024] [Indexed: 01/11/2024] Open
Abstract
Perinatal exposure to a high-fat, high-sugar Western-style diet (WSD) is associated with altered neural circuitry in the melanocortin system. This association may have an underlying inflammatory component, as consumption of a WSD during pregnancy can lead to an elevated inflammatory environment. Our group previously demonstrated that prenatal WSD exposure was associated with increased markers of inflammation in the placenta and fetal hypothalamus in Japanese macaques. In this follow-up study, we sought to determine whether this heightened inflammatory state persisted into the postnatal period, as prenatal exposure to inflammation has been shown to reprogram offspring immune function and long-term neuroinflammation would present a potential means for prolonged disruptions to microglia-mediated neuronal circuit formation. Neuroinflammation was approximated in 1-yr-old offspring by counting resident microglia and peripherally derived macrophages in the region of the hypothalamus examined in the fetal study, the arcuate nucleus (ARC). Microglia and macrophages were immunofluorescently stained with their shared marker, ionized calcium-binding adapter molecule 1 (Iba1), and quantified in 11 regions along the rostral-caudal axis of the ARC. A mixed-effects model revealed main effects of perinatal diet (P = 0.011) and spatial location (P = 0.003) on Iba1-stained cell count. Perinatal WSD exposure was associated with a slight decrease in the number of Iba1-stained cells, and cells were more densely located in the center of the ARC. These findings suggest that the heightened inflammatory state experienced in utero does not persist postnatally. This inflammatory response trajectory could have important implications for understanding how neurodevelopmental disorders progress.NEW & NOTEWORTHY Prenatal Western-style diet exposure is associated with increased microglial activity in utero. However, we found a potentially neuroprotective reduction in microglia count during early postnatal development. This trajectory could inform the timing of disruptions to microglia-mediated neuronal circuit formation. Additionally, this is the first study in juvenile macaques to characterize the distribution of microglia along the rostral-caudal axis of the arcuate nucleus of the hypothalamus. Nearby neuronal populations may be greater targets during inflammatory insults.
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Affiliation(s)
- Samantha Papadakis
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, United States
- Department of Psychiatry, Oregon Health & Science University, Portland, Oregon, United States
| | - Jacqueline R Thompson
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States
| | - Eric Feczko
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, Minnesota, United States
- Masonic Institute for the Developing Brain, University of Minnesota Medical School, Minneapolis, Minnesota, United States
| | - Oscar Miranda-Dominguez
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, Minnesota, United States
- Masonic Institute for the Developing Brain, University of Minnesota Medical School, Minneapolis, Minnesota, United States
| | - Geoffrey A Dunn
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States
| | - Matthew Selby
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States
| | - A J Mitchell
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, United States
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States
| | - Elinor L Sullivan
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, United States
- Department of Psychiatry, Oregon Health & Science University, Portland, Oregon, United States
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States
| | - Damien A Fair
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, Minnesota, United States
- Masonic Institute for the Developing Brain, University of Minnesota Medical School, Minneapolis, Minnesota, United States
- Institute of Child Development, College of Education and Human Development, University of Minnesota, Minneapolis, Minnesota, United States
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Yang JW, Zou Y, Chen J, Cui C, Song J, Yang MM, Gao J, Hu HQ, Xia LQ, Wang LM, Lv XY, Chen L, Hou XG. Didymin alleviates metabolic dysfunction-associated fatty liver disease (MAFLD) via the stimulation of Sirt1-mediated lipophagy and mitochondrial biogenesis. J Transl Med 2023; 21:921. [PMID: 38115075 PMCID: PMC10731721 DOI: 10.1186/s12967-023-04790-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 12/08/2023] [Indexed: 12/21/2023] Open
Abstract
BACKGROUND Metabolic dysfunction-associated fatty liver disease (MAFLD) is one of the most prevalent metabolic syndromes worldwide. However, no approved pharmacological treatments are available for MAFLD. Chenpi, one kind of dried peel of citrus fruits, has traditionally been utilized as a medicinal herb for liver diseases. Didymin is a newly identified oral bioactive dietary flavonoid glycoside derived from Chenpi. In this study, we investigated the therapeutic potential of Didymin as an anti-MAFLD drug and elucidated its underlying mechanisms. METHODS High-fat diet (HFD)-induced MAFLD mice and alpha mouse liver 12 (AML12) cells were utilized to evaluate the effects and mechanisms of Didymin in the treatment of MAFLD. Liver weight, serum biochemical parameters, and liver morphology were examined to demonstrate the therapeutic efficacy of Didymin in MAFLD treatment. RNA-seq analysis was performed to identify potential pathways that could be affected by Didymin. The impact of Didymin on Sirt1 was corroborated through western blot, molecular docking analysis, microscale thermophoresis (MST), and deacetylase activity assay. Then, a Sirt1 inhibitor (EX-527) was utilized to confirm that Didymin alleviates MAFLD via Sirt1. Western blot and additional assays were used to investigate the underlying mechanisms. RESULTS Our results suggested that Didymin may possess therapeutic potential against MAFLD in vitro and in vivo. By promoting Sirt1 expression as well as directly binding to and activating Sirt1, Didymin triggers downstream pathways that enhance mitochondrial biogenesis and function while reducing apoptosis and enhancing lipophagy. CONCLUSIONS These suggest that Didymin could be a promising medication for MAFLD treatment. Furthermore, its therapeutic effects are mediated by Sirt1.
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Affiliation(s)
- Jing-Wen Yang
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Ying Zou
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Jun Chen
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Chen Cui
- Department of Endocrinology, The Second Hospital of Shandong University, Jinan, China
| | - Jia Song
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Meng-Meng Yang
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Jing Gao
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Hui-Qing Hu
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Long-Qing Xia
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Li-Ming Wang
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Xiao-Yu Lv
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Li Chen
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
- Key Laboratory of Endocrine and Metabolic Diseases, Shandong Province Medicine & Health, Jinan, China
- Jinan Clinical Research Center for Endocrine and Metabolic Disease, Jinan, China
- Institute of Endocrine and Metabolic Diseases, Shandong University, Jinan, China
- National Key Laboratory for Innovation and Transformation of Luobing Theory, Jinan, China
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, Jinan, China
| | - Xin-Guo Hou
- Department of Endocrinology, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China.
- Key Laboratory of Endocrine and Metabolic Diseases, Shandong Province Medicine & Health, Jinan, China.
- Jinan Clinical Research Center for Endocrine and Metabolic Disease, Jinan, China.
- Institute of Endocrine and Metabolic Diseases, Shandong University, Jinan, China.
- National Key Laboratory for Innovation and Transformation of Luobing Theory, Jinan, China.
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, Jinan, China.
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Delle C, Cankar N, Digebjerg Holgersson C, Hvorup Knudsen H, Schiøler Nielsen E, Kjaerby C, Mori Y, Nedergaard M, Weikop P. Long-term high-fat diet increases glymphatic activity in the hypothalamus in mice. Sci Rep 2023; 13:4137. [PMID: 36914703 PMCID: PMC10011420 DOI: 10.1038/s41598-023-30630-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 02/27/2023] [Indexed: 03/16/2023] Open
Abstract
Obesity affects millions of people worldwide and is associated with an increased risk of cognitive decline. The glymphatic system is a brain-wide metabolic waste clearance system, dysfunction of which is linked to dementia. We herein examined glymphatic transport in mice with long-term obesity induced by a high-fat diet for 10 months. The obese mice developed hypertension and elevated heart rate, neuroinflammation and gliosis, but not apparent systemic inflammation. Surprisingly, glymphatic inflow was globally unaffected by the high-fat diet except for the hypothalamus, which displayed increased influx and elevated AQP4 vascular polarization compared to the normal weight control group. We propose that a long-term high-fat diet induced metabolic alteration of hypothalamic neurons and neuroinflammation, which in turn enhanced glymphatic clearance in the effected brain region.
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Affiliation(s)
- Christine Delle
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Neža Cankar
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Christian Digebjerg Holgersson
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Helle Hvorup Knudsen
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Elise Schiøler Nielsen
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Celia Kjaerby
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Yuki Mori
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark.
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY, 14642, USA.
| | - Pia Weikop
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
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Mikhailova EV, Derkach KV, Shpakov AO, Romanova IV. Melanocortin 1 Receptors in the Hypothalamus of Mice within the Norm and in Diet-Induced Obesity. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022040263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Wu Y, Hu S, Yang D, Li L, Li B, Wang L, Li M, Wang G, Li J, Xu Y, Zhang X, Niu C, Speakman JR. Increased Variation in Body Weight and Food Intake Is Related to Increased Dietary Fat but Not Increased Carbohydrate or Protein in Mice. Front Nutr 2022; 9:835536. [PMID: 35360679 PMCID: PMC8963818 DOI: 10.3389/fnut.2022.835536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 01/28/2022] [Indexed: 12/23/2022] Open
Abstract
A variety of inbred mouse strains have been used for research in metabolic disorders. Despite being inbred, they display large inter-individual variability for many traits like food intake and body weight. However, the relationship between dietary macronutrients and inter-individual variation in body weight and food intake of different mouse strains is still unclear. We investigated the association between macronutrient content of the diet and variations in food intake, body composition, and glucose tolerance by exposing five different mouse strains (C57BL/6, BALB/c, C3H, DBA/2, and FVB) to 24 different diets with variable protein, fat, and carbohydrate contents. We found only increasing dietary fat, but not protein or carbohydrate had a significant association (positive) with variation in both food intake and body weight. The highest variation in both body weight and food intake occurred with 50% dietary fat. However, there were no significant relationships between the variation in fat and lean mass with dietary protein, fat, or carbohydrate levels. In addition, none of the dietary macronutrients had significant impacts on the variation in glucose tolerance ability in C57BL/6 mice. In conclusion, the variations in food intake and body weight changes increased with the elevation of dietary fat levels.
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Affiliation(s)
- Yingga Wu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Sumei Hu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Engineering and Technology Research Center of Food Additives, National Soybean Processing Industry Technology Innovation Center, Beijing Technology and Business University, Beijing, China
| | - Dengbao Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Li Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Baoguo Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Lu Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Min Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, United Kingdom
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Guanlin Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | | | - Yanchao Xu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Xueying Zhang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, United Kingdom
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Chaoqun Niu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - John R. Speakman
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, United Kingdom
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- CAS Center of Excellence in Animal Evolution and Genetics, Kunming, China
- *Correspondence: John R. Speakman
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Doucette WT, Smedley EB, Ruiz-Jaquez M, Khokhar JY, Smith KS. Chronic Chemogenetic Manipulation of Ventral Pallidum Targeted Neurons in Male Rats Fed an Obesogenic Diet. Brain Res 2022; 1784:147886. [DOI: 10.1016/j.brainres.2022.147886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 02/14/2022] [Accepted: 03/16/2022] [Indexed: 11/26/2022]
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Pang H, Li J, Wang Y, Su X, Gao Y, Li SJ. Mice lacking the proton channel Hv1 exhibit sex-specific differences in glucose homeostasis. J Biol Chem 2021; 297:101212. [PMID: 34547291 PMCID: PMC8503595 DOI: 10.1016/j.jbc.2021.101212] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/07/2021] [Accepted: 09/16/2021] [Indexed: 02/07/2023] Open
Abstract
Sex as a physiologic factor has a strong association with the features of metabolic syndrome. Our previous study showed that loss of the voltage-gated proton channel Hv1 inhibits insulin secretion and leads to hyperglycemia and glucose intolerance in male mice. However, there are significant differences in blood glucose between male and female Hv1-knockout (KO) mice. Here, we investigated the differences in glucose metabolism and insulin sensitivity between male and female KO mice and how sex steroids contribute to these differences. We found that the fasting blood glucose in female KO mice was visibly lower than that in male KO mice, which was accompanied by hypotestosteronemia. KO mice in both sexes exhibited higher expression of gluconeogenesis-related genes in liver compared with WT mice. Also, the livers from KO males displayed a decrease in glycolysis-related gene expression and an increase in gluconeogenesis-related gene expression compared with KO females. Furthermore, exogenous testosterone supplementation decreased blood glucose levels in male KO mice, as well as enhancing insulin signaling. Taken together, our data demonstrate that knockout of Hv1 results in higher blood glucose levels in male than female mice, despite a decreased insulin secretion in both sexes. This sex-related difference in glucose homeostasis is associated with the glucose metabolism in liver tissue, likely due to the physiological levels of testosterone in KO male mice.
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Affiliation(s)
- Huimin Pang
- Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin, PR China
| | - Jinzhi Li
- Biology Laboratory, Tianjin High School, Tianjin, PR China
| | - Yuzhou Wang
- Laboratory Animal Center, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Xiaomin Su
- Laboratory Animal Center, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Yingtang Gao
- Tianjin Key Laboratory of Extracorporeal Life Support for Critical Diseases, Institute of Hepatobiliary Disease, Nankai University Affiliated Third Center Hospital, Tianjin, PR China.
| | - Shu Jie Li
- Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin, PR China; Biomedical Research Center, Qilu Institute of Technology, Shandong, PR China.
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8
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Sarangi M, Dus M. Crème de la Créature: Dietary Influences on Behavior in Animal Models. Front Behav Neurosci 2021; 15:746299. [PMID: 34658807 PMCID: PMC8511460 DOI: 10.3389/fnbeh.2021.746299] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 09/06/2021] [Indexed: 11/13/2022] Open
Abstract
In humans, alterations in cognitive, motivated, and affective behaviors have been described with consumption of processed diets high in refined sugars and saturated fats and with high body mass index, but the causes, mechanisms, and consequences of these changes remain poorly understood. Animal models have provided an opportunity to answer these questions and illuminate the ways in which diet composition, especially high-levels of added sugar and saturated fats, contribute to brain physiology, plasticity, and behavior. Here we review findings from invertebrate (flies) and vertebrate models (rodents, zebrafish) that implicate these diets with changes in multiple behaviors, including eating, learning and memory, and motivation, and discuss limitations, open questions, and future opportunities.
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Affiliation(s)
| | - Monica Dus
- Department of Molecular, Cellular, and Developmental Biology, The University of Michigan, Ann Arbor, MI, United States
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Gauda EB, Conde S, Bassi M, Zoccal DB, Almeida Colombari DS, Colombari E, Despotovic N. Leptin: Master Regulator of Biological Functions that Affects Breathing. Compr Physiol 2020; 10:1047-1083. [PMID: 32941688 DOI: 10.1002/cphy.c190031] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Obesity is a global epidemic in developed countries accounting for many of the metabolic and cardiorespiratory morbidities that occur in adults. These morbidities include type 2 diabetes, sleep-disordered breathing (SDB), obstructive sleep apnea, chronic intermittent hypoxia, and hypertension. Leptin, produced by adipocytes, is a master regulator of metabolism and of many other biological functions including central and peripheral circuits that control breathing. By binding to receptors on cells and neurons in the brainstem, hypothalamus, and carotid body, leptin links energy and metabolism to breathing. In this comprehensive article, we review the central and peripheral locations of leptin's actions that affect cardiorespiratory responses during health and disease, with a particular focus on obesity, SDB, and its effects during early development. Obesity-induced hyperleptinemia is associated with centrally mediated hypoventilation with decrease CO2 sensitivity. On the other hand, hyperleptinemia augments peripheral chemoreflexes to hypoxia and induces sympathoexcitation. Thus, "leptin resistance" in obesity is relative. We delineate the circuits responsible for these divergent effects, including signaling pathways. We review the unique effects of leptin during development on organogenesis, feeding behavior, and cardiorespiratory responses, and how undernutrition and overnutrition during critical periods of development can lead to cardiorespiratory comorbidities in adulthood. We conclude with suggestions for future directions to improve our understanding of leptin dysregulation and associated clinical diseases and possible therapeutic targets. Lastly, we briefly discuss the yin and the yang, specifically the contribution of relative adiponectin deficiency in adults with hyperleptinemia to the development of metabolic and cardiovascular disease. © 2020 American Physiological Society. Compr Physiol 10:1047-1083, 2020.
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Affiliation(s)
- Estelle B Gauda
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Silvia Conde
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Lisboa, Portugal
| | - Mirian Bassi
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Daniel B Zoccal
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Debora Simoes Almeida Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Nikola Despotovic
- Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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10
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Ramírez-Sánchez M, Prieto I, Segarra AB, Martínez-Cañamero M, Banegas I, de Gasparo M. Enkephalinase regulation. VITAMINS AND HORMONES 2019; 111:105-129. [PMID: 31421697 DOI: 10.1016/bs.vh.2019.05.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
After millennia of knowledge of opium, it was only recently that endogenous substances called opioids with similar properties to opium and derivatives were discovered. The first to be discovered were enkephalins. In addition to the regulation of their synthesis and expression of receptors, an important mechanism for the regulation of their functions carried out by multiple proteolytic enzymes acting at all levels of their structure is described. The action of such enzymes, known as enkephalinases, is also regulated by endogenous and exogenous factors which ultimately affect the control of the enkephalins's action. For therapeutic purposes, it is not only necessary to develop specific inhibitors but also to acquire a deep knowledge of the influence that such factors exert on their activities. This knowledge could help us to establish adapted therapeutic strategies in the treatment of pain or other processes in which enkephalinases are involved. In this chapter, some of these regulatory factors are discussed, such as regional and subcellular distribution, developmental changes, diurnal variations, hormonal influences, stress, dietary factors or interactions with other neurotransmitters.
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Affiliation(s)
| | - Isabel Prieto
- Department of Health Sciences, University of Jaén, Jaén, Spain
| | | | | | | | - Marc de Gasparo
- Cardiovascular & Metabolic Syndrome Adviser, Rossemaison, Switzerland
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11
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Nyamugenda E, Trentzsch M, Russell S, Miles T, Boysen G, Phelan KD, Baldini G. Injury to hypothalamic Sim1 neurons is a common feature of obesity by exposure to high-fat diet in male and female mice. J Neurochem 2019; 149:73-97. [PMID: 30615192 DOI: 10.1111/jnc.14662] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 10/16/2018] [Accepted: 01/04/2019] [Indexed: 12/13/2022]
Abstract
The hypothalamus is essential for regulation of energy homeostasis and metabolism. Feeding hypercaloric, high-fat (HF) diet induces hypothalamic arcuate nucleus injury and alters metabolism more severely in male than in female mice. The site(s) and extent of hypothalamic injury in male and female mice are not completely understood. In the paraventricular nucleus (PVN) of the hypothalamus, single-minded family basic helix-loop helix transcription factor 1 (Sim1) neurons are essential to control energy homeostasis. We tested the hypothesis that exposure to HF diet induces injury to Sim1 neurons in the PVN of male and female mice. Mice expressing membrane-bound enhanced green fluorescent protein (mEGFP) in Sim1 neurons (Sim1-Cre:Rosa-mEGFP mice) were generated to visualize the effects of exposure to HF diet on these neurons. Male and female Sim1-Cre:Rosa-mEGFP mice exposed to HF diet had increased weight, hyperleptinemia, and developed hepatosteatosis. In male and female mice exposed to HF diet, expression of mEGFP was reduced by > 40% in Sim1 neurons of the PVN, an effect paralleled by cell apoptosis and neuronal loss, but not by microgliosis. In the arcuate nucleus of the Sim1-Cre:Rosa-mEGFP male mice, there was decreased alpha-melanocyte-stimulating hormone in proopiomelanocortin neurons projecting to the PVN, with increased cell apoptosis, neuronal loss, and microgliosis. These defects were undetectable in the arcuate nucleus of female mice exposed to the HF diet. Thus, injury to Sim1 neurons of the PVN is a shared feature of exposure to HF diet in mice of both sexes, while injury to proopiomelanocortin neurons in arcuate nucleus is specific to male mice. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.
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Affiliation(s)
- Eugene Nyamugenda
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Marcus Trentzsch
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Susan Russell
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Tiffany Miles
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Gunnar Boysen
- Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.,The Winthrop P Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Kevin D Phelan
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Giulia Baldini
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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12
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Attenuation of diet-induced hypothalamic inflammation following bariatric surgery in female mice. Mol Med 2018; 24:56. [PMID: 30355312 PMCID: PMC6201532 DOI: 10.1186/s10020-018-0057-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/09/2018] [Indexed: 12/14/2022] Open
Abstract
Background Exposure of rodents to chronic high-fat diet (HFD) results in upregulation of inflammatory markers and proliferation of microglia within the mediobasal hypothalamus. Such hypothalamic inflammation is associated with metabolic dysfunction, central leptin resistance, and maintenance of obesity. Bariatric surgeries result in long-term stable weight loss and improved metabolic function. However, the effects of such surgical procedures on HFD-induced hypothalamic inflammation are unknown. We sought to characterize the effects of two bariatric surgical procedures, Roux-en-Y gastric bypass (RYGB) and biliary diversion (BD-IL), in female mice with particular emphasis on HFD-induced hypothalamic inflammation and microgliosis. Methods RYGB and BD-IL were performed on diet-induced obese (DIO) mice. Quantitative RT-PCR and fluorescent microscopy were used to evaluate hypothalamic inflammatory gene expression and microgliosis. Results were compared to lean (CD), DIO sham-surgerized mice (DIO-SHAM), and dietary weight loss (DIO-Rev) controls. Results In female mice, RYGB and BD-IL result in normalization of hypothalamic inflammatory gene expression and microgliosis within 8 weeks of surgery, despite ongoing exposure to HFD. Paralleling these results, the hypothalamic expression levels of the orexigenic neuropeptide Agrp and the anorexic response of surgical mice to exogenous leptin were comparable to lean controls (CD). In contrast, results from DIO-Rev mice were comparable to DIO-SHAM mice, despite transition back to standard rodent show and normalization of weight. Conclusion Bariatric surgery attenuates HFD-induced hypothalamic inflammation and microgliosis and restores leptin sensitivity, despite ongoing exposure to HFD.
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13
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Functional Interrogation of the AgRP Neural Circuits in Control of Appetite, Body Weight, and Behaviors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1090:1-16. [PMID: 30390282 DOI: 10.1007/978-981-13-1286-1_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neurons expressing agouti-related protein (AgRP), the so-called hunger neurons, protect mammals from starvation by promoting food-seeking behaviors (Trends Neurosci 36:504-512, 2013). Now an increasing amount of evidence show that these hunger-sensing neurons not only motivate animals to forage and ingest food but also help conserve energy by inhibiting innate processes that demand large amounts of energy such as growth, reproduction, and stress response. It has further been perceived that AgRP neurons transmit signals with negative valence to reward and cognitive centers so as to engage the motivational behavior toward seeking and obtaining foods (Physiol Behav 190:34-42, 2017). Recent advancement in genome editing and neurotechniques unleashed an escalated research of uniquely defined neuronal populations and neural circuits underlying the behavioral regulation of body weight and food responses (Nat Biotechnol 32:347-355, 2014; Proc Natl Acad Sci 113, 2016). In this chapter we will review literatures describing the functional organization of the AgRP circuit and its correlative signaling components that influence ingestive, foraging, motivational, and cognitive responses, a framework that reshaped our thinking toward the new hope and challenges in treatment of obesity and eating disorders.
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14
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Cooney KA, Molden BM, Kowalczyk NS, Russell S, Baldini G. Lipid stress inhibits endocytosis of melanocortin-4 receptor from modified clathrin-enriched sites and impairs receptor desensitization. J Biol Chem 2017; 292:17731-17745. [PMID: 28878020 DOI: 10.1074/jbc.m117.785758] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 08/12/2017] [Indexed: 11/06/2022] Open
Abstract
Melanocortin-4 receptor (MC4R) is a G-protein-coupled receptor expressed in the brain's hypothalamus where it regulates energy homeostasis. MC4R agonists function to lower food intake and weight. In this respect, although obesity promotes hyperlipidemia and hypothalamic injury, MC4R agonists are nevertheless more effective to reduce food intake within hours of administration in overweight, rather than lean, mice. MC4R undergoes constitutive internalization and recycling to the plasma membrane with agonist binding inducing receptor retention along the intracellular route and, under prolonged exposure, desensitization. Here, we found that, in neuronal cells, lipid stress by exposure to elevated palmitate leaves unchanged the rate by which MC4R and transferrin receptor are constitutively excluded from the cell surface. However, lipid stress disrupted later steps of MC4R and transferrin receptor internalization to endosomes as well as traffic of agonist-occupied MC4R to lysosomes and MC4R desensitization. In the lipid-stressed cells, MC4R and clathrin were redistributed to the plasma membrane where they colocalized to sites that appeared by super-resolution microscopy to be modified and to have higher clathrin content than those of cells not exposed to elevated palmitate. The data suggest that lipid stress disrupts steps of endocytosis following MC4R localization to clathrin-coated sites and exclusion of the receptor from the extracellular medium. We conclude that increased effectiveness of MC4R agonists in obesity may be an unexpected outcome of neuronal injury with disrupted clathrin-dependent endocytosis and impaired receptor desensitization.
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Affiliation(s)
- Kimberly A Cooney
- From the Department of Biochemistry and Molecular Biology University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205-7199
| | - Brent M Molden
- From the Department of Biochemistry and Molecular Biology University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205-7199
| | - Nicholas S Kowalczyk
- From the Department of Biochemistry and Molecular Biology University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205-7199
| | - Susan Russell
- From the Department of Biochemistry and Molecular Biology University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205-7199
| | - Giulia Baldini
- From the Department of Biochemistry and Molecular Biology University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205-7199
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15
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Shin AC, Filatova N, Lindtner C, Chi T, Degann S, Oberlin D, Buettner C. Insulin Receptor Signaling in POMC, but Not AgRP, Neurons Controls Adipose Tissue Insulin Action. Diabetes 2017; 66:1560-1571. [PMID: 28385803 PMCID: PMC5440019 DOI: 10.2337/db16-1238] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 03/22/2017] [Indexed: 12/31/2022]
Abstract
Insulin is a key regulator of adipose tissue lipolysis, and impaired adipose tissue insulin action results in unrestrained lipolysis and lipotoxicity, which are hallmarks of the metabolic syndrome and diabetes. Insulin regulates adipose tissue metabolism through direct effects on adipocytes and through signaling in the central nervous system by dampening sympathetic outflow to the adipose tissue. Here we examined the role of insulin signaling in agouti-related protein (AgRP) and pro-opiomelanocortin (POMC) neurons in regulating hepatic and adipose tissue insulin action. Mice lacking the insulin receptor in AgRP neurons (AgRP IR KO) exhibited impaired hepatic insulin action because the ability of insulin to suppress hepatic glucose production (hGP) was reduced, but the ability of insulin to suppress lipolysis was unaltered. To the contrary, in POMC IR KO mice, insulin lowered hGP but failed to suppress adipose tissue lipolysis. High-fat diet equally worsened glucose tolerance in AgRP and POMC IR KO mice and their respective controls but increased hepatic triglyceride levels only in POMC IR KO mice, consistent with impaired lipolytic regulation resulting in fatty liver. These data suggest that although insulin signaling in AgRP neurons is important in regulating glucose metabolism, insulin signaling in POMC neurons controls adipose tissue lipolysis and prevents high-fat diet-induced hepatic steatosis.
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Affiliation(s)
- Andrew C Shin
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Nika Filatova
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Claudia Lindtner
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Tiffany Chi
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Seta Degann
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Douglas Oberlin
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Christoph Buettner
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
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16
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Nakata M, Yamamoto S, Okada T, Yada T. AAV-mediated IL-10 gene transfer counteracts inflammation in the hypothalamic arcuate nucleus and obesity induced by high-fat diet. Neuropeptides 2017; 62:87-92. [PMID: 27939689 DOI: 10.1016/j.npep.2016.11.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/05/2016] [Accepted: 11/27/2016] [Indexed: 12/16/2022]
Abstract
Consumption of high-fat diet (HFD) induces energy imbalance and consequently obesity. In the pathogenesis of obesity, HFD triggers inflammation in the hypothalamus including arcuate nucleus (ARC). Interleukin-10 (IL-10) is a representative anti-inflammatory cytokine, known to ameliorate the adipose tissue inflammation and insulin resistance in obesity. However, the effect of IL-10 on the hypothalamic inflammation remains less defined. We here report the effect of over-expression of murine IL-10 using adeno-associated virus (AAV) vector on the inflammation in ARC and feeding behavior in HFD-induced obese (DIO) mice. DIO mice exhibited reduced POMC expression and elevated IKKs (IκB kinases) and SOCS3 expression in ARC. Overexpression of mIL-10 using AAV vector ameliorated obesity in parallel with restoration of ARC POMC expression in DIO mice. Moreover, IL-10 treatment suppressed IKKs activation and SOCS3 expression in ARC of DIO mice. These results suggest that IL-10 gene transfer provides an effective approach for counteracting HFD-induced inflammation and leptin resistance in ARC to prevent progression of obesity.
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Affiliation(s)
- Masanori Nakata
- Department of Physiology, Division of Integrative Physiology, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan.
| | - Sawako Yamamoto
- Department of Physiology, Division of Integrative Physiology, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan
| | - Takashi Okada
- Department of Molecular and Medical Genetics, Nippon Medical School, Tokyo 113-8602, Japan
| | - Toshihiko Yada
- Department of Physiology, Division of Integrative Physiology, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan.
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17
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Gilland KE, Fox EA. Effect of food deprivation or short-term Western diet feeding on BDNF protein expression in the hypothalamic arcuate, paraventricular, and ventromedial nuclei. Am J Physiol Regul Integr Comp Physiol 2017; 312:R611-R625. [PMID: 28202438 DOI: 10.1152/ajpregu.00256.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 02/01/2017] [Accepted: 02/06/2017] [Indexed: 12/15/2022]
Abstract
Mutations in the brain-derived neurotrophic factor (BDNF) gene are associated with human obesity, and BDNF has potent inhibitory effects on eating and body weight. Little is known about the effects of energy balance manipulations on BDNF protein in the hypothalamus, though this brain region is critical for regulation of feeding and body weight and has high levels of BDNF. Here we investigated the effects of negative and positive energy status on BDNF protein levels in the arcuate (ARC), paraventricular, and ventromedial (VMH) hypothalamic nuclei and the ectorhinal cortex. To achieve this, mice were food deprived for 48 h or fed a Western diet (WD), a restricted amount of WD, or chow for 6 h, 48 h, 1 wk, or 3 wk. BDNF protein levels were estimated as the number of neurons in each brain region that exhibited BDNF-like immunoreactivity. Food deprivation decreased BDNF protein (and mRNA) expression in the ARC compared with fed mice (32%). In contrast, 1 wk of WD consumption increased BDNF protein expression in the VMH compared with chow or restricted WD feeding (40%) and, unexpectedly, increased BDNF protein in the ectorhinal cortex (20%). Furthermore, of the diet conditions and durations tested, only 1 wk of WD consumption was associated with both hyperphagia and excess weight, suggesting that effects of one or both contributed to the changes in BDNF levels. The decrease in ARC BDNF may support increased feeding in food-deprived mice, whereas the increase in the VMH may moderate overeating in WD-fed mice.
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Affiliation(s)
- Kaitlyn E Gilland
- Behavioral Neurogenetics Laboratory, Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
| | - Edward A Fox
- Behavioral Neurogenetics Laboratory, Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
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18
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Tumour biology of obesity-related cancers: understanding the molecular concept for better diagnosis and treatment. Tumour Biol 2016; 37:14363-14380. [PMID: 27623943 DOI: 10.1007/s13277-016-5357-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 09/07/2016] [Indexed: 12/18/2022] Open
Abstract
Obesity continues to be a major global problem. Various cancers are related to obesity and proper understanding of their aetiology, especially their molecular tumour biology is important for early diagnosis and better treatment. Genes play an important role in the development of obesity. Few genes such as leptin, leptin receptor encoded by the db (diabetes), pro-opiomelanocortin, AgRP and NPY and melanocortin-4 receptors and insulin-induced gene 2 were linked to obesity. MicroRNAs control gene expression via mRNA degradation and protein translation inhibition and influence cell differentiation, cell growth and cell death. Overexpression of miR-143 inhibits tumour growth by suppressing B cell lymphoma 2, extracellular signal-regulated kinase-5 activities and KRAS oncogene. Cancers of the breast, uterus, renal, thyroid and liver are also related to obesity. Any disturbance in the production of sex hormones and insulin, leads to distortion in the balance between cell proliferation, differentiation and apoptosis. The possible mechanism linking obesity to cancer involves alteration in the level of adipokines and sex hormones. These mediators act as biomarkers for cancer progression and act as targets for cancer therapy and prevention. Interestingly, many anti-cancerous drugs are also beneficial in treating obesity and vice versa. We also reviewed the possible link in the mechanism of few drugs which act both on cancer and obesity. The present review may be important for molecular biologists, oncologists and clinicians treating cancers and also pave the way for better therapeutic options.
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19
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Identification of mutations through dominant screening for obesity using C57BL/6 substrains. Sci Rep 2016; 6:32453. [PMID: 27585985 PMCID: PMC5009433 DOI: 10.1038/srep32453] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 08/10/2016] [Indexed: 01/05/2023] Open
Abstract
The discovery of leptin substantiated the usefulness of a forward genetic approach in elucidating the molecular network regulating energy metabolism. However, no successful dominant screening for obesity has been reported, which may be due to the influence of quantitative trait loci between the screening and counter strains and the low fertility of obese mice. Here, we performed a dominant screening for obesity using C57BL/6 substrains, C57BL/6J and C57BL/6N, with the routine use of in vitro fertilization. The screening of more than 5000 mutagenized mice established two obese pedigrees in which single nucleotide substitutions in Mc4r and Sim1 genes were identified through whole-exome sequencing. The mutation in the Mc4r gene produces a premature stop codon, and the mutant SIM1 protein lacks transcriptional activity, showing that the haploinsufficiency of SIM1 and MC4R results in obesity. We further examined the hypothalamic neuropeptide expressions in the mutant pedigrees and mice with diet-induced obesity, which showed that each obesity mouse model has distinct neuropeptide expression profiles. This forward genetic screening scheme is useful and applicable to any research field in which mouse models work.
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20
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Kwon EJ, Lee HA, You YA, Park H, Cho SJ, Ha EH, Kim YJ. DNA methylations of MC4R and HNF4α are associated with increased triglyceride levels in cord blood of preterm infants. Medicine (Baltimore) 2016; 95:e4590. [PMID: 27583872 PMCID: PMC5008556 DOI: 10.1097/md.0000000000004590] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The association of preterm birth with obesity and metabolic syndrome later in life is well established. Although the biological mechanism for this association is poorly understood, epigenetic alterations of metabolic-related genes in early life may have important roles in metabolic dysfunction. Thus, we investigated the associations of DNA methylations of melanocortin 4 receptor (MC4R) and hepatocyte nuclear factor 4 alpha (HNF4α) with metabolic profiles in cord blood of term and preterm infants.We measured metabolic profiles in cord blood samples of 85 term and 85 preterm infants. DNA methylation and mRNA expression levels of MC4R and HNF4α in cord blood cells were quantified using pyrosequencing and real-time PCR. Triglyceride (TG) levels were grouped by percentile as low (<10th percentile), mid (11th-89th percentiles), and high (>90th percentile). A multiple linear regression model was used to assess the differential effects of DNA methylation on metabolic indices in cord blood between term and preterm infants.The beta-coefficients for associations between TG levels and methylation statuses of MC4R-CpG3 and HNF4α-CpG2 in the P1 promoter differed significantly between term and preterm infants (P = 0.04 and P = 0.003, respectively). DNA methylation statuses of MC4R-CpG3 and HNF4α-CpG2 in the P1 promoter were significantly lower in preterm infants in the high-TG group compared with those in the mid- and low-TG groups (P = 0.01). Notably, preterm infants in the high-TG group had higher TG levels in cord blood than term infants in the high-TG group (60.49 vs 54.57 mg/dL). In addition, MC4R and HNF4α expression levels were higher in preterm infants than in term infants (P < 0.05).Epigenetic alterations of the newly identified genes MC4R and HNF4α in early life might contribute to metabolic profile changes, especially increased TG levels, in the cord blood of preterm infants.
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Affiliation(s)
- Eun Jin Kwon
- Department of Obstetrics and Gynecology
- Department of Occupational and Environmental Medicine
| | | | | | | | - Su Jin Cho
- Department of Pediatrics, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - Eun Hee Ha
- Department of Occupational and Environmental Medicine
| | - Young Ju Kim
- Department of Obstetrics and Gynecology
- Correspondence: Young Ju Kim, Department of Obstetrics and Gynecology, School of Medicine, Ewha Womans University, 1071 Anyangcheon-ro, Yangcheon-ku, Seoul 158-710, Republic of Korea (e-mail: )
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21
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Souza GFP, Solon C, Nascimento LF, De-Lima-Junior JC, Nogueira G, Moura R, Rocha GZ, Fioravante M, Bobbo V, Morari J, Razolli D, Araujo EP, Velloso LA. Defective regulation of POMC precedes hypothalamic inflammation in diet-induced obesity. Sci Rep 2016; 6:29290. [PMID: 27373214 PMCID: PMC4931679 DOI: 10.1038/srep29290] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 06/17/2016] [Indexed: 11/23/2022] Open
Abstract
Obesity is the result of a long-term positive energy balance in which caloric intake overrides energy expenditure. This anabolic state results from the defective activity of hypothalamic neurons involved in the sensing and response to adiposity. However, it is currently unknown what the earliest obesity-linked hypothalamic defect is and how it orchestrates the energy imbalance present in obesity. Using an outbred model of diet-induced obesity we show that defective regulation of hypothalamic POMC is the earliest marker distinguishing obesity-prone from obesity-resistant mice. The early inhibition of hypothalamic POMC was sufficient to transform obesity-resistant in obesity-prone mice. In addition, the post-prandial change in the blood level of β-endorphin, a POMC-derived peptide, correlates with body mass gain in rodents and humans. Taken together, these results suggest that defective regulation of POMC expression, which leads to a change of β-endorphin levels, is the earliest hypothalamic defect leading to obesity.
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Affiliation(s)
- Gabriela F P Souza
- Laboratory of Cell Signaling, University of Campinas, 13084-970 - Campinas-SP, Brazil
| | - Carina Solon
- Laboratory of Cell Signaling, University of Campinas, 13084-970 - Campinas-SP, Brazil
| | - Lucas F Nascimento
- Laboratory of Cell Signaling, University of Campinas, 13084-970 - Campinas-SP, Brazil
| | - Jose C De-Lima-Junior
- Laboratory of Cell Signaling, University of Campinas, 13084-970 - Campinas-SP, Brazil
| | - Guilherme Nogueira
- Laboratory of Cell Signaling, University of Campinas, 13084-970 - Campinas-SP, Brazil
| | - Rodrigo Moura
- Laboratory of Cell Signaling, University of Campinas, 13084-970 - Campinas-SP, Brazil
| | - Guilherme Z Rocha
- Department of Internal Medicine, University of Campinas, 13084-970 - Campinas-SP, Brazil
| | - Milena Fioravante
- Laboratory of Cell Signaling, University of Campinas, 13084-970 - Campinas-SP, Brazil
| | - Vanessa Bobbo
- Laboratory of Cell Signaling, University of Campinas, 13084-970 - Campinas-SP, Brazil.,Faculty of Nursing, University of Campinas, 13084-970 - Campinas-SP, Brazil
| | - Joseane Morari
- Laboratory of Cell Signaling, University of Campinas, 13084-970 - Campinas-SP, Brazil
| | - Daniela Razolli
- Laboratory of Cell Signaling, University of Campinas, 13084-970 - Campinas-SP, Brazil
| | - Eliana P Araujo
- Laboratory of Cell Signaling, University of Campinas, 13084-970 - Campinas-SP, Brazil.,Faculty of Nursing, University of Campinas, 13084-970 - Campinas-SP, Brazil
| | - Licio A Velloso
- Laboratory of Cell Signaling, University of Campinas, 13084-970 - Campinas-SP, Brazil
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22
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Poon K, Alam M, Karatayev O, Barson JR, Leibowitz SF. Regulation of the orexigenic neuropeptide, enkephalin, by PPARδ and fatty acids in neurons of the hypothalamus and forebrain. J Neurochem 2015; 135:918-31. [PMID: 26332891 DOI: 10.1111/jnc.13298] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 07/28/2015] [Accepted: 08/23/2015] [Indexed: 11/28/2022]
Abstract
Ingestion of a high-fat diet composed mainly of the saturated fatty acid, palmitic (PA), and the unsaturated fatty acid, oleic (OA), stimulates transcription in the brain of the opioid neuropeptide, enkephalin (ENK), which promotes intake of substances of abuse. To understand possible underlying mechanisms, this study examined the nuclear receptors, peroxisome proliferator-activated receptors (PPARs), and tested in hypothalamic and forebrain neurons from rat embryos whether PPARs regulate endogenous ENK and the fatty acids themselves affect these PPARs and ENK. The first set of experiments demonstrated that knocking down PPARδ, but not PPARα or PPARγ, increased ENK transcription, activation of PPARδ by an agonist decreased ENK levels, and PPARδ neurons coexpressed ENK, suggesting that PPARδ negatively regulates ENK. In the second set of experiments, PA treatment of hypothalamic and forebrain neurons had no effect on PPARδ protein while stimulating ENK mRNA and protein, whereas OA increased both mRNA and protein levels of PPARδ in forebrain neurons while having no effect on ENK mRNA and increasing ENK levels. These findings show that PA has a strong, stimulatory effect on ENK and weak effect on PPARδ protein, whereas OA has a strong stimulatory effect on PPARδ and weak effect on ENK, consistent with the inhibitory effect of PPARδ on ENK. They suggest a function for PPARδ, perhaps protective in nature, in embryonic neurons exposed to fatty acids from a fat-rich diet and provide evidence for a mechanism contributing to differential effects of saturated and monounsaturated fatty acids on neurochemical systems involved in consummatory behavior. Our findings show that PPARδ in forebrain and hypothalamic neurons negatively regulates enkephalin (ENK), a peptide known to promote ingestive behavior. This inverse relationship is consistent with our additional findings, that a saturated (palmitic; PA) compared to a monounsaturated fatty acid (oleic; OA) has a strong stimulatory effect on ENK and weak effect on PPARδ. These results suggest that PPARδ protects against the neuronal effects of fatty acids, which differentially affect neurochemical systems involved in ingestive behavior.
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Affiliation(s)
- Kinning Poon
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York City, New York, USA
| | - Mohammad Alam
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York City, New York, USA
| | - Olga Karatayev
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York City, New York, USA
| | - Jessica R Barson
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York City, New York, USA
| | - Sarah F Leibowitz
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York City, New York, USA
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Koganei M, Saitou Y, Tsuchiya K, Abe F, Tanaka T, Horinouchi I, Izumi Y, Yamaji T, Takahashi T. Effects of 5-aminolevulinic acid on a murine model of diet-induced obesity. J Clin Biochem Nutr 2015; 57:145-50. [PMID: 26388673 PMCID: PMC4566019 DOI: 10.3164/jcbn.13-58] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 03/05/2015] [Indexed: 12/25/2022] Open
Abstract
The effects of 5-aminolevulinic acid (5-ALA) on obesity were investigated using a murine model (diet-induced obese mice). Diet-induced obese mice were divided into 4 groups: a control group (C group), which was fed a high-fat diet; a low-5-ALA dose (10 mg/kg/day) group (10A group); a moderate-5-ALA dose (30 mg/kg/day) group (30A group); and a high-5-ALA dose (100 mg/kg/day) group (100A group). 5-ALA was administered by mixing the high fat diet for 8 weeks. Body weight increases in the 30A and 100A groups were significantly smaller compared with those of the C group. Body fat measurements by X-ray computed tomography indicated that the 100A group showed a tendency toward low visceral fat quantities during the final week of the study. Visceral fat weights in the 30A and 100A groups were slightly low. The levels of serum alanine aminotransferase (ALT) and total cholesterol (TC) in the 10A group was slightly low, whereas the 30A and 100A groups showed significantly lower ALT and TC values. Liver lipid concentration showed a dose-dependent decrease with ALA. Thus, in this diet-induced obese murine model, administration of 5-ALA had a significantly beneficial impact on the visceral fat, serum ALT and TC, and liver lipid concentration.
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Affiliation(s)
- Megumi Koganei
- Nutrition Research Department, Food Science Research Laboratories, Meiji Co., Ltd., 540 Naruda, Odawara, Kanagawa 250-0862, Japan
| | - Yuri Saitou
- Nutrition Research Department, Food Science Research Laboratories, Meiji Co., Ltd., 540 Naruda, Odawara, Kanagawa 250-0862, Japan
| | - Kyoko Tsuchiya
- SBI Pharma Co., Ltd., Izumi Garden Tower 20F, 1-6-1 Roppongi, Minato, Tokyo 106-6020, Japan
| | - Fuminori Abe
- SBI Pharma Co., Ltd., Izumi Garden Tower 20F, 1-6-1 Roppongi, Minato, Tokyo 106-6020, Japan
| | - Toru Tanaka
- SBI Pharma Co., Ltd., Izumi Garden Tower 20F, 1-6-1 Roppongi, Minato, Tokyo 106-6020, Japan
| | - Izumi Horinouchi
- Biomaterial in Tokyo Co., Ltd., 5-4-19-301B Kashiwanoha, Kashiwa, Chiba 277-0882, Japan
| | - Yoshiya Izumi
- Biomaterial in Tokyo Co., Ltd., 5-4-19-301B Kashiwanoha, Kashiwa, Chiba 277-0882, Japan
| | - Taketo Yamaji
- Nutrition Research Department, Food Science Research Laboratories, Meiji Co., Ltd., 540 Naruda, Odawara, Kanagawa 250-0862, Japan
| | - Takeshi Takahashi
- Nutrition Research Department, Food Science Research Laboratories, Meiji Co., Ltd., 540 Naruda, Odawara, Kanagawa 250-0862, Japan
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Fam BC, Sgambellone R, Ruan Z, Proietto J, Andrikopoulos S. Contribution of the hypothalamus and gut to weight gain susceptibility and resistance in mice. J Endocrinol 2015; 225:191-204. [PMID: 25934705 DOI: 10.1530/joe-15-0131] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/30/2015] [Indexed: 12/15/2022]
Abstract
Obesity susceptibility in humans and in rodent strains varies in response to the consumption of high-energy density (HED) diets. However, the exact mechanism(s) involved in this susceptibility remain(s) unresolved. The aim of the present study was to gain greater insight into this susceptibility by using C57BL/6J (B6) mice that were separated into obesity-prone (diet-induced obese (DIO)) and obesity-resistant (diet-induced resistant (DR)) groups following an HED diet for 6 weeks. Physiological, biochemical and gene expression assessments of energy balance were performed in the DIO and DR mice on an HED diet and chow-fed mice. The increased weight gain of the DIO mice as compared to the DR mice was associated with increased energy intake and higher plasma leptin and adiponectin levels but not with reduced physical activity or resting energy expenditure. Hypothalamic Pomc gene expression was elevated, but there were no changes in Npy or Agrp expression. Adipose tissue leptin and adiponectin gene expression were significantly reduced in the DIO group as compared to the DR group. Interestingly, ileum expression of G protein-coupled receptor (Gpr) 40 (Gpr40) was significantly increased, whereas Gpr120, Gpr119, Gpr41, and glucagon-like peptide 1 (Glp1) were reduced. Contrastingly, the lower weight gain of the DR group was associated with elevated adipose tissue leptin and adiponectin gene expression, but there were no differences in plasma hormone or hypothalamic gene expression levels as compared to chow-fed mice. Therefore, the present data demonstrate that susceptibility and resistance to diet-induced weight gain in B6 mice appears to be predominantly driven by peripheral rather than hypothalamic modifications, and changes in gut-specific receptors are a potentially important contributor to this variation.
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Affiliation(s)
- Barbara C Fam
- Department of Medicine (Austin Health) Austin Hospital, The University of Melbourne, Level 7, Lance Townsend Building, Studley Road, Heidelberg, Victoria 3084, Australia
| | - Rebecca Sgambellone
- Department of Medicine (Austin Health) Austin Hospital, The University of Melbourne, Level 7, Lance Townsend Building, Studley Road, Heidelberg, Victoria 3084, Australia
| | - Zheng Ruan
- Department of Medicine (Austin Health) Austin Hospital, The University of Melbourne, Level 7, Lance Townsend Building, Studley Road, Heidelberg, Victoria 3084, Australia
| | - Joseph Proietto
- Department of Medicine (Austin Health) Austin Hospital, The University of Melbourne, Level 7, Lance Townsend Building, Studley Road, Heidelberg, Victoria 3084, Australia
| | - Sofianos Andrikopoulos
- Department of Medicine (Austin Health) Austin Hospital, The University of Melbourne, Level 7, Lance Townsend Building, Studley Road, Heidelberg, Victoria 3084, Australia
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25
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Ho AL, Sussman ES, Zhang M, Pendharkar AV, Azagury DE, Bohon C, Halpern CH. Deep Brain Stimulation for Obesity. Cureus 2015; 7:e259. [PMID: 26180683 PMCID: PMC4494510 DOI: 10.7759/cureus.259] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2015] [Indexed: 12/20/2022] Open
Abstract
Obesity is now the third leading cause of preventable death in the US, accounting for 216,000 deaths annually and nearly 100 billion dollars in health care costs. Despite advancements in bariatric surgery, substantial weight regain and recurrence of the associated metabolic syndrome still occurs in almost 20-35% of patients over the long-term, necessitating the development of novel therapies. Our continually expanding knowledge of the neuroanatomic and neuropsychiatric underpinnings of obesity has led to increased interest in neuromodulation as a new treatment for obesity refractory to current medical, behavioral, and surgical therapies. Recent clinical trials of deep brain stimulation (DBS) in chronic cluster headache, Alzheimer's disease, and depression and obsessive-compulsive disorder have demonstrated the safety and efficacy of targeting the hypothalamus and reward circuitry of the brain with electrical stimulation, and thus provide the basis for a neuromodulatory approach to treatment-refractory obesity. In this study, we review the literature implicating these targets for DBS in the neural circuitry of obesity. We will also briefly review ethical considerations for such an intervention, and discuss genetic secondary-obesity syndromes that may also benefit from DBS. In short, we hope to provide the scientific foundation to justify trials of DBS for the treatment of obesity targeting these specific regions of the brain.
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Affiliation(s)
- Allen L Ho
- Department of Neurosurgery, Stanford University School of Medicine
| | - Eric S Sussman
- Department of Neurosurgery, Stanford School of Medicine/Stanford University Medical Center
| | - Michael Zhang
- Department of Neurosurgery, Stanford University School of Medicine
| | | | - Dan E Azagury
- Department of Surgery, Stanford School of Medicine/Stanford University Medical Center
| | - Cara Bohon
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine
| | - Casey H Halpern
- Department of Neurosurgery, Stanford University Medical Center
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26
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Cyr NE, Steger JS, Toorie AM, Yang JZ, Stuart R, Nillni EA. Central Sirt1 regulates body weight and energy expenditure along with the POMC-derived peptide α-MSH and the processing enzyme CPE production in diet-induced obese male rats. Endocrinology 2015; 156:961-74. [PMID: 25549049 PMCID: PMC4330311 DOI: 10.1210/en.2014-1970] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In the periphery, the nutrient-sensing enzyme Sirtuin 1 (silent mating type information regulation 2 homolog 1 [Sirt1]) reduces body weight in diet-induced obese (DIO) rodents. However, the role of hypothalamic Sirt1 in body weight and energy balance regulation is debated. The first studies to reveal that central Sirt1 regulates body weight came from experiments in our laboratory using Sprague-Dawley rats. Central inhibition of Sirt1 decreased body weight and food intake as a result of a forkhead box protein O1 (FoxO1)-mediated increase in the anorexigenic proopiomelanocortin (POMC) and decrease in the orexigenic Agouti-related peptide in the hypothalamic arcuate nucleus. Here, we demonstrate that central inhibition of Sirt1 in DIO decreased body weight and increased energy expenditure at higher levels as compared with the lean counterpart. Brain Sirt1 inhibition in DIO increased acetylated FoxO1, which in turn increased phosphorylated FoxO1 via improved insulin/phosphorylated AKT signaling. Elevated acetylated FoxO1 and phosphorylated FoxO1 increased POMC along with the α-melanocyte-stimulating hormone (α-MSH) maturation enzyme carboxypeptidase E, which resulted in more of the bioactive POMC product α-MSH released into the paraventricular nucleus. Increased in α-MSH led to augmented TRH levels and circulating T3 levels (triiodothyronine, thyroid hormone). These results indicate that inhibiting hypothalamic Sirt1 in DIO enhances the activity of the hypothalamic-pituitary-thyroid axis, which stimulates energy expenditure. Because we show that blocking central Sirt1 causes physiological changes that promote a negative energy balance in an obese individual, our results support brain Sirt1 as a significant target for weight loss therapeutics.
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Affiliation(s)
- Nicole E Cyr
- Division of Endocrinology (N.E.C., J.S.S., A.M.T., J.Z.Y., R.S., E.A.N.), Department of Medicine, The Warren Alpert Medical School of Brown University/Rhode Island Hospital, Providence, Rhode Island 02903; and Department of Molecular Biology, Cell Biology, and Biochemistry (E.A.N.), Brown University, Providence, Rhode Island 02912
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Duan K, Yu W, Lin Z, Tan S, Bai X, Gao T, Xi F, Li N. Endotoxemia-induced muscle wasting is associated with the change of hypothalamic neuropeptides in rats. Neuropeptides 2014; 48:379-86. [PMID: 25459520 DOI: 10.1016/j.npep.2014.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 10/08/2014] [Accepted: 10/09/2014] [Indexed: 11/21/2022]
Abstract
In critical patients, sepsis-induced muscle wasting is considered to be an important contributor to complications and mortality. Previous work mainly focuses on the peripheral molecular mechanism of muscle degradation, however little evidence exists for the role of central nervous system in the process. In the present study, we, for the first time, characterized the relationship between muscle wasting and central neuropeptide changes in a septic model. Thirty-six adult male Sprague-Dawley rats were intraperitoneally injected with lipopolysaccharide (LPS) or saline. Twelve, 24 and 48 hrs after injection, skeletal muscle and hypothalamus tissues were harvested. Muscle wasting was measured by the mRNA expression of two E3 ubiquitin ligases, muscle ring finger 1 (MuRF-1) and muscle atrophy F-box (MAFbx), as well as 3-methyl-histidine (3-MH) and tyrosine release. Hypothalamic neuropeptides and inflammatory marker expressions were also measured in three time points. LPS injection caused an increase expression of MuRF-1 and MAFbx, and a significant higher release of 3-MH and tyrosine. Hypothalamic neuropeptides, proopiomelanocortin (POMC), cocaine- and amphetamine-regulated transcript (CART), agouti-related protein (AgRP) and neuropeptide Y (NPY) presented a dynamic change after LPS injection. Also, hypothalamic inflammatory markers, interleukin-1 β (IL-1β) and tumor necrosis factor α (TNF-α) increased substantially after LPS administration. Importantly, the expressions of POMC, AgRP and CART were well correlated with muscle atrophy gene, MuRF-1 expression. These findings suggest hypothalamic peptides and inflammation may participate in the sepsis-induced muscle wasting, but the exact mechanism needs further study.
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Affiliation(s)
- Kaipeng Duan
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China
| | - Wenkui Yu
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China.
| | - Zhiliang Lin
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China
| | - Shanjun Tan
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China
| | - Xiaowu Bai
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China
| | - Tao Gao
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China
| | - Fengchan Xi
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China
| | - Ning Li
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China.
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28
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Yang Y, Smith DL, Keating KD, Allison DB, Nagy TR. Variations in body weight, food intake and body composition after long-term high-fat diet feeding in C57BL/6J mice. Obesity (Silver Spring) 2014; 22:2147-55. [PMID: 24942674 PMCID: PMC4180788 DOI: 10.1002/oby.20811] [Citation(s) in RCA: 198] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 06/04/2014] [Indexed: 12/05/2022]
Abstract
OBJECTIVE To investigate the variations in body weight, food intake, and body composition of both male and female C57BL/6J mice during a diet-induced obesity model with high-fat diet (HFD) feeding. METHODS Mice were individually housed and fed ad libitum either a low-fat diet (LFD, 10% calories from fat; n = 15 male, n = 15 female) or HFD (45% calories from fat; n = 277 male, n = 278 female) from 8 to 43 weeks of age. Body weight, food intake, and body composition were routinely measured. RESULTS Body weight was significantly increased with HFD (vs. LFD) in males from week 14 (P = 0.0221) and in females from week 27 (P = 0.0076). Fat mass and fat-free mass of all groups were significantly increased over time (all P < 0.0001), with a large variation observed in fat mass. Baseline fat mass, fat-free mass, and daily energy intake were significant predictors of future body weight for both sexes (P < 0.0001). Baseline fat mass was a significant predictor of future body fat (P < 0.0001). CONCLUSIONS Both males and females have large variations in fat mass, and this variability increases over time, while that of fat-free mass remains relatively stable. Sex differences exist in HFD responses and multivariate predicting models of body weight.
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Affiliation(s)
- Yongbin Yang
- Department of Nutrition Sciences University of Alabama at Birmingham, Birmingham, AL 35294
- Nutrition Obesity Research Center University of Alabama at Birmingham, Birmingham, AL 35294
| | - Daniel L. Smith
- Department of Nutrition Sciences University of Alabama at Birmingham, Birmingham, AL 35294
- Nutrition Obesity Research Center University of Alabama at Birmingham, Birmingham, AL 35294
| | - Karen D. Keating
- Nutrition Obesity Research Center University of Alabama at Birmingham, Birmingham, AL 35294
- Office of Energetics University of Alabama at Birmingham, Birmingham, AL 35294
| | - David B. Allison
- Department of Nutrition Sciences University of Alabama at Birmingham, Birmingham, AL 35294
- Nutrition Obesity Research Center University of Alabama at Birmingham, Birmingham, AL 35294
- Office of Energetics University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Biostatistics University of Alabama at Birmingham, Birmingham, AL 35294
- Diabetes Research Center, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Tim R. Nagy
- Department of Nutrition Sciences University of Alabama at Birmingham, Birmingham, AL 35294
- Nutrition Obesity Research Center University of Alabama at Birmingham, Birmingham, AL 35294
- Diabetes Research Center, University of Alabama at Birmingham, Birmingham, AL 35294
- Corresponding Author: Tim R. Nagy, Department of Nutrition Sciences, Webb 421 University of Alabama at Birmingham, 1720 2nd Ave S, Birmingham AL 35294-3360 Phone: 205-934-4088, Fax: 205-975-0750,
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29
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Azzout-Marniche D, Chaumontet C, Nadkarni NA, Piedcoq J, Fromentin G, Tomé D, Even PC. Food intake and energy expenditure are increased in high-fat-sensitive but not in high-carbohydrate-sensitive obesity-prone rats. Am J Physiol Regul Integr Comp Physiol 2014; 307:R299-309. [DOI: 10.1152/ajpregu.00065.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Obesity-prone (OP) rodents are used as models of human obesity predisposition. The goal of the present study was to identify preexisting defects in energy expenditure components in OP rats. Two studies were performed. In the first one, male Wistar rats ( n = 48) were fed a high-carbohydrate diet (HCD) for 3 wk and then a high-fat diet (HFD) for the next 3 wk. This study showed that adiposity gain under HCD was 2.9-fold larger in carbohydrate-sensitive (CS) than in carbohydrate-resistant (CR) rats, confirming the concept of “carbohydrate-sensitive” rats. Energy expenditure (EE), respiratory quotient (RQ), caloric intake (CI), and locomotor activity measured during HFD identified no differences in EE and RQ between fat-resistant (FR) and fat-sensitive (FS) rats, and indicated that obesity developed in FS rats only as the result of a larger CI not fully compensated by a parallel increase in EE. A specific pattern of spontaneous activity, characterized by reduced activity burst intensity, was identified in FS rats but not in CS ones. This mirrors a previous observation that under HCD, CS but not FS rats, exhibited bursts of activity of reduced intensity. In a second study, rats were fed a HFD for 3 wk, and the components of energy expenditure were examined by indirect calorimetry in 10 FR and 10 FS rats. This study confirmed that a low basal EE, reduced thermic effect of feeding, defective postprandial energy partitioning, or a defective substrate utilization by the working muscle are not involved in the FS phenotype.
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Affiliation(s)
- Dalila Azzout-Marniche
- Institut National de la Recherche Agronomique, Centre de Recherche en Nutrition Humaine d'Ile-de-France (CRNH-IdF), UMR 914 Nutrition Physiology and Ingestive Behavior, Paris, France; and
- AgroParisTech, CRNH-IdF, UMR 914 Nutrition Physiology and Ingestive Behavior, Paris, France
| | - Catherine Chaumontet
- Institut National de la Recherche Agronomique, Centre de Recherche en Nutrition Humaine d'Ile-de-France (CRNH-IdF), UMR 914 Nutrition Physiology and Ingestive Behavior, Paris, France; and
- AgroParisTech, CRNH-IdF, UMR 914 Nutrition Physiology and Ingestive Behavior, Paris, France
| | - Nachiket A. Nadkarni
- Institut National de la Recherche Agronomique, Centre de Recherche en Nutrition Humaine d'Ile-de-France (CRNH-IdF), UMR 914 Nutrition Physiology and Ingestive Behavior, Paris, France; and
- AgroParisTech, CRNH-IdF, UMR 914 Nutrition Physiology and Ingestive Behavior, Paris, France
| | - Julien Piedcoq
- Institut National de la Recherche Agronomique, Centre de Recherche en Nutrition Humaine d'Ile-de-France (CRNH-IdF), UMR 914 Nutrition Physiology and Ingestive Behavior, Paris, France; and
- AgroParisTech, CRNH-IdF, UMR 914 Nutrition Physiology and Ingestive Behavior, Paris, France
| | - Gilles Fromentin
- Institut National de la Recherche Agronomique, Centre de Recherche en Nutrition Humaine d'Ile-de-France (CRNH-IdF), UMR 914 Nutrition Physiology and Ingestive Behavior, Paris, France; and
- AgroParisTech, CRNH-IdF, UMR 914 Nutrition Physiology and Ingestive Behavior, Paris, France
| | - Daniel Tomé
- Institut National de la Recherche Agronomique, Centre de Recherche en Nutrition Humaine d'Ile-de-France (CRNH-IdF), UMR 914 Nutrition Physiology and Ingestive Behavior, Paris, France; and
- AgroParisTech, CRNH-IdF, UMR 914 Nutrition Physiology and Ingestive Behavior, Paris, France
| | - Patrick C. Even
- Institut National de la Recherche Agronomique, Centre de Recherche en Nutrition Humaine d'Ile-de-France (CRNH-IdF), UMR 914 Nutrition Physiology and Ingestive Behavior, Paris, France; and
- AgroParisTech, CRNH-IdF, UMR 914 Nutrition Physiology and Ingestive Behavior, Paris, France
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30
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Cyr NE, Steger JS, Toorie AM, Yang JZ, Stuart R, Nillni EA. Central Sirt1 regulates body weight and energy expenditure along with the POMC-derived peptide α-MSH and the processing enzyme CPE production in diet-induced obese male rats. Endocrinology 2014; 155:2423-35. [PMID: 24773342 PMCID: PMC4060185 DOI: 10.1210/en.2013-1998] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In the periphery, the nutrient-sensing enzyme Sirtuin 1 (silent mating type information regulation 2 homolog 1 [Sirt1]) reduces body weight in diet-induced obese (DIO) rodents. However, the role of Sirt1 in the brain, particularly the hypothalamus, in body weight and energy balance regulation is debated. Among the first studies to reveal that central Sirt1 regulates body weight came from experiments in our laboratory using Sprague Dawley rats. In that study, central inhibition of Sirt1 decreased body weight and food intake as a result of a Forkhead box protein O1 (FoxO1)-mediated increase in the anorexigenic proopiomelanocortin (POMC) and decrease in the orexigenic Agouti-related peptide in the hypothalamic arcuate nucleus. Here, we demonstrate that central inhibition of Sirt1 in DIO decreased body weight and increased energy expenditure at higher levels as compared with the lean counterpart. Brain Sirt1 inhibition in DIO increased acetylated FoxO1, which, in turn, increased phosphorylated FoxO1 via improved insulin/pAKT signaling. Elevated acetylated FoxO1 and phosphorylated FoxO1 increased POMC along with the α-MSH maturation enzyme carboxypeptidase E, which resulted in more of the bioactive POMC product α-MSH released into the paraventricular nucleus. Increased in α-MSH led to augmented TRH levels and circulating T3 levels (thyroid hormone). These results indicate that inhibiting hypothalamic Sirt1 in DIO enhances the activity of the hypothalamic-pituitary-thyroid axis, which stimulates energy expenditure. Because we show that blocking central Sirt1 causes physiological changes that promote a negative energy balance in an obese individual, our results support brain Sirt1 as a significant target for weight loss therapeutics.
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Affiliation(s)
- Nicole E Cyr
- Division of Endocrinology (N.E.C, J.S.S., A.M.T., J.Z.Y, R.S., E.A.N.), Department of Medicine, The Warren Alpert Medical School of Brown University/Rhode Island Hospital, Providence, Rhode Island 02903; and Department of Molecular Biology, Cell Biology and Biochemistry (E.A.N.), Brown University, Providence, Rhode Island 02912
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31
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Mercer AJ, Stuart RC, Attard CA, Otero-Corchon V, Nillni EA, Low MJ. Temporal changes in nutritional state affect hypothalamic POMC peptide levels independently of leptin in adult male mice. Am J Physiol Endocrinol Metab 2014; 306:E904-15. [PMID: 24518677 PMCID: PMC3989737 DOI: 10.1152/ajpendo.00540.2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Hypothalamic proopiomelanocortin (POMC) neurons constitute a critical anorexigenic node in the central nervous system (CNS) for maintaining energy balance. These neurons directly affect energy expenditure and feeding behavior by releasing bioactive neuropeptides but are also subject to signals directly related to nutritional state such as the adipokine leptin. To further investigate the interaction of diet and leptin on hypothalamic POMC peptide levels, we exposed 8- to 10-wk-old male POMC-Discosoma red fluorescent protein (DsRed) transgenic reporter mice to either 24-48 h (acute) or 2 wk (chronic) food restriction, high-fat diet (HFD), or leptin treatment. Using semiquantitative immunofluorescence and radioimmunoassays, we discovered that acute fasting and chronic food restriction decreased the levels of adrenocorticotropic hormone (ACTH), α-melanocyte-stimulating hormone (α-MSH), and β-endorphin in the hypothalamus, together with decreased DsRed fluorescence, compared with control ad libitum-fed mice. Furthermore, acute but not chronic HFD or leptin administration selectively increased α-MSH levels in POMC fibers and increased DsRed fluorescence in POMC cell bodies. HFD and leptin treatments comparably increased circulating leptin levels at both time points, suggesting that transcription of Pomc and synthesis of POMC peptide products are not modified in direct relation to the concentration of plasma leptin. Our findings indicate that negative energy balance persistently downregulated POMC peptide levels, and this phenomenon may be partially explained by decreased leptin levels, since these changes were blocked in fasted mice treated with leptin. In contrast, sustained elevation of plasma leptin by HFD or hormone supplementation did not significantly alter POMC peptide levels, indicating that enhanced leptin signaling does not chronically increase Pomc transcription and peptide synthesis.
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Affiliation(s)
- Aaron J Mercer
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
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32
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Marco A, Kisliouk T, Weller A, Meiri N. High fat diet induces hypermethylation of the hypothalamic Pomc promoter and obesity in post-weaning rats. Psychoneuroendocrinology 2013; 38:2844-53. [PMID: 23958347 DOI: 10.1016/j.psyneuen.2013.07.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 07/17/2013] [Accepted: 07/18/2013] [Indexed: 02/04/2023]
Abstract
Impaired response of the brain to the leptin signal leads to a persisting dysregulation of food intake and energy balance. High plasma leptin or insulin should activate proopiomelanocortin (POMC), the precursor of the anorexigenic neuropeptide α-melanocyte-stimulating hormone (α-MSH) in the hypothalamic arcuate nucleus (ARC). Nevertheless, in obesity, this signal transduction pathway might be impaired. In this study we investigated whether chronic high fat (HF) diet consumption from post-weaning to adulthood increases CpG methylation of the Pomc promoter. The hypothesis that this would disrupt the essential binding of the transcription factor Sp1 to the Pomc promoter was tested. Male rats were raised from postnatal day 21 till 90 on either HF or standard diet. As a result HF fed rats were significantly heavier, with high leptin and insulin levels in their plasma but almost no changes in ARC mRNA expression levels of Pomc. The Pomc promoter area in the HF-treated rats was found to be hypermethylated. Furthermore, there was a direct correlation in individual rats between CpG methylation at specific sites that affect Sp1 binding and plasma leptin levels and/or body weight. Although, as expected the HF diet resulted in up-regulation of Sp1, the binding of Sp1 to the hypermethylated Pomc promoter was significantly reduced. Therefore, we suggest that hypermethylation on the promoter region of the Pomc gene can emerge at post-lactation periods and interfere with transcription factor binding, thus blocking the effects of high leptin levels, leading to obesity.
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Affiliation(s)
- Asaf Marco
- Faculty of Life Sciences, Bar Ilan University, Ramat-Gan 52900, Israel; Gonda Brain Res Center, Bar Ilan University, Ramat-Gan 52900, Israel.
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Ribeiro G, Santos O. Recompensa alimentar: mecanismos envolvidos e implicações para a obesidade. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.rpedm.2013.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Tan JTM, McLennan SV, Williams PF, Rezaeizadeh A, Lo LWY, Bonner JG, Twigg SM. Connective tissue growth factor/CCN-2 is upregulated in epididymal and subcutaneous fat depots in a dietary-induced obesity model. Am J Physiol Endocrinol Metab 2013; 304:E1291-302. [PMID: 23571711 DOI: 10.1152/ajpendo.00654.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Connective tissue growth factor (CTGF), also known as CCN-2, is a cysteine-rich secreted protein that is involved in a range of biological processes, including regulation of cell growth and differentiation. Our previous in vitro studies have shown that CCN-2 inhibits adipocyte differentiation, although whether CCN-2 is regulated in vivo in adipogenesis is undetermined and was investigated in this study. C57BL/6 male mice were fed either standard laboratory chow (ND) or a diet high in fat (HFD; 45% fat) for 15 or 24 wk. HFD animals that gained >5 g in weight (termed HFD-fat) were insulin resistant and were compared with HFD-fed animals, which failed to gain weight (termed HFD-lean). HFD-fat mice had significantly increased CCN-2 mRNA levels in both the subcutaneous and epididymal fat pads, whereas CCN-2 mRNA was not induced in the epididymal site in HFD-lean mice. Also in HFD-fed animals, epididymal CCN-2 mRNA correlated positively with key genes involved in adipocyte differentiation, adiponectin and PPARγ (P < 0.001 and P < 0.002, respectively). Additionally, epididymal CCN-2 mRNA correlated positively with two markers of tissue turnover, PAI-1 in HFD-fat mice only and TIMP-1, but only in the HFD-lean mice. Collectively, these findings suggest that CCN-2 plays a role in adipocyte differentiation in vivo and thus in the pathogenesis of obesity linked with insulin resistance.
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Affiliation(s)
- Joanne T M Tan
- Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia; and
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Cakir I, Cyr NE, Perello M, Litvinov BP, Romero A, Stuart RC, Nillni EA. Obesity induces hypothalamic endoplasmic reticulum stress and impairs proopiomelanocortin (POMC) post-translational processing. J Biol Chem 2013; 288:17675-88. [PMID: 23640886 DOI: 10.1074/jbc.m113.475343] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
It was shown previously that abnormal prohormone processing or inactive proconverting enzymes that are responsible for this processing cause profound obesity. Our laboratory demonstrated earlier that in the diet-induced obesity (DIO) state, the appetite-suppressing neuropeptide α-melanocyte-stimulating hormone (α-MSH) is reduced, yet the mRNA of its precursor protein proopiomelanocortin (POMC) remained unaltered. It was also shown that the DIO condition promotes the development of endoplasmic reticulum (ER) stress and leptin resistance. In the current study, using an in vivo model combined with in vitro experiments, we demonstrate that obesity-induced ER stress obstructs the post-translational processing of POMC by decreasing proconverting enzyme 2, which catalyzes the conversion of adrenocorticotropin to α-MSH, thereby decreasing α-MSH peptide production. This novel mechanism of ER stress affecting POMC processing in DIO highlights the importance of ER stress in regulating central energy balance in obesity.
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Affiliation(s)
- Isin Cakir
- Division of Endocrinology, Department of Medicine, Warren Alpert Medical School of Brown University/Rhode Island Hospital, Providence, Rhode Island 02907, USA
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Lukaszewski MA, Butruille L, Moitrot E, Montel V, Dickes-Coopman A, Lesage J, Laborie C, Vieau D, Breton C. The hypothalamic POMC mRNA expression is upregulated in prenatally undernourished male rat offspring under high-fat diet. Peptides 2013; 43:146-54. [PMID: 23523777 DOI: 10.1016/j.peptides.2013.03.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/13/2013] [Accepted: 03/13/2013] [Indexed: 12/31/2022]
Abstract
Epidemiological studies demonstrated that adverse environmental factors leading to intrauterine growth retardation (IUGR) and low birth weight may predispose individuals to increased risk of metabolic syndrome. In rats, we previously demonstrated that adult male IUGR offspring from prenatal 70% food-restricted dams throughout gestation (FR30) were predisposed to energy balance dysfunctions such as impaired glucose intolerance, hyperleptinemia, hyperphagia and adiposity. We investigated whether postweaning moderate high-fat (HF) diet would amplify the phenotype focusing on the hypothalamus gene expression profile. Prenatally undernourished rat offspring were HF-fed from weaning until adulthood while body weight and food intake were measured. Tissue weights, glucose tolerance and plasma endocrine parameters levels were determined in 4-month-old rats. Hypothalamic gene expression profiling of adult FR30 rat was performed using Illumina microarray analysis and the RatRef-12 Expression BeadChip that contains 21,792 rat genes. Under HF diet, contrary to C animals, FR30 rats displayed increased body weight. However, most of the endocrine disorders observed in chow diet-fed adult FR30 were alleviated. We also observed very few gene expression changes in hypothalamus of FR30 rat. Amongst factors involved in hypothalamic energy homeostasis programming system, only the POMC and transthyretin mRNA expression levels were preferentially increased under HF diet. Both elevated gene expression levels may be seen as adaptive mechanisms counteracting against deleterious effects of HF feeding in FR30 animals. This study shows that the POMC gene expression is a key target of long-term developmental programming in prenatally undernourished male rat offspring, specifically within an obesogenic environment.
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Affiliation(s)
- Marie-Amélie Lukaszewski
- Unité Environnement Périnatal et Croissance, UPRES EA 4489, Equipe Dénutritions Maternelles Périnatales, Université Lille-Nord de France, Villeneuve d'Ascq, France
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Byerly MS, Swanson RD, Semsarzadeh NN, McCulloh PS, Kwon K, Aja S, Moran TH, Wong GW, Blackshaw S. Identification of hypothalamic neuron-derived neurotrophic factor as a novel factor modulating appetite. Am J Physiol Regul Integr Comp Physiol 2013; 304:R1085-95. [PMID: 23576617 DOI: 10.1152/ajpregu.00368.2012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Disruption of finely coordinated neuropeptide signals in the hypothalamus can result in altered food intake and body weight. We identified neuron-derived neurotrophic factor (NENF) as a novel secreted protein through a large-scale screen aimed at identifying novel secreted hypothalamic proteins that regulate food intake. We observed robust Nenf expression in hypothalamic nuclei known to regulate food intake, and its expression was altered under the diet-induced obese (DIO) condition relative to the fed state. Hypothalamic Nenf mRNA was regulated by brain-derived neurotrophic factor (BDNF) signaling, itself an important regulator of appetite. Delivery of purified recombinant BDNF into the lateral cerebral ventricle decreased hypothalamic Nenf expression, while pharmacological inhibition of trkB signaling increased Nenf mRNA expression. Furthermore, recombinant NENF administered via an intracerebroventricular cannula decreased food intake and body weight and increased hypothalamic Pomc and Mc4r mRNA expression. Importantly, the appetite-suppressing effect of NENF was abrogated in obese mice fed a high-fat diet, demonstrating a diet-dependent modulation of NENF function. We propose the existence of a regulatory circuit involving BDNF, NENF, and melanocortin signaling. Our study validates the power of using an integrated experimental and bioinformatic approach to identify novel CNS-derived proteins with appetite-modulating function and reveals NENF as an important central modulator of food intake.
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Affiliation(s)
- Mardi S Byerly
- Department of Physiology and Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Sikalidis AK, Fitch MD, Fleming SE. Diet induced obesity increases the risk of colonic tumorigenesis in mice. Pathol Oncol Res 2013; 19:657-66. [PMID: 23536280 DOI: 10.1007/s12253-013-9626-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 03/06/2013] [Indexed: 02/07/2023]
Abstract
A large body of epidemiological data indicates that obesity increases the risk of colon cancer in humans. There are limited studies using rodent models where the relationship between obesity and colon cancer has been studied. In this study, wild-type diet-induced obese (DIO) mice and lean wild-type controls were used to investigate the influence of obesity on the risk of colon cancer. We hypothesized that the obese phenotype would exhibit increased colonic tumorigenesis. Colon cancer was chemically induced by injecting the mice with azoxymethane (AOM) at levels that we experimentally determined to result in equivalent AOM concentrations in circulating blood. Risk of colon cancer was assessed via microscopic examination of entire colons for aberrant crypts, aberrant crypt foci and proliferation levels. The DIO mice were found to have significantly more aberrant crypts and aberrant crypt foci as well as increased proliferation of colonocytes per mouse compared to wild-type control mice, supporting the epidemiological data that obesity increases the risk of colonic tumorigenesis.
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Affiliation(s)
- Angelos K Sikalidis
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, CA, 94720, USA,
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Scopinho A, Fortaleza E, Corrêa F, Resstel L. Medial amygdaloid nucleus 5-HT2C receptors are involved in the hypophagic effect caused by zimelidine in rats. Neuropharmacology 2012; 63:301-9. [DOI: 10.1016/j.neuropharm.2012.03.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 03/21/2012] [Accepted: 03/24/2012] [Indexed: 10/28/2022]
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Fox EA, Biddinger JE. Early postnatal overnutrition: potential roles of gastrointestinal vagal afferents and brain-derived neurotrophic factor. Physiol Behav 2012; 106:400-12. [PMID: 22712064 PMCID: PMC3517218 DOI: 10.1016/j.physbeh.2012.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Abnormal perinatal nutrition (APN) results in a predisposition to develop obesity and the metabolic syndrome and thus may contribute to the prevalence of these disorders. Obesity, including that which develops in organisms exposed to APN, has been associated with increased meal size. Vagal afferents of the gastrointestinal (GI) tract contribute to regulation of meal size by transmitting satiation signals from gut-to-brain. Consequently, APN could increase meal size by altering this signaling, possibly through changes in expression of factors that control vagal afferent development or function. Here two studies that addressed these possibilities are reviewed. First, meal patterns, meal microstructure, and the structure and density of vagal afferents that innervate the intestine were examined in mice that experienced early postnatal overnutrition (EPO). These studies provided little evidence for EPO effects on vagal afferents as it did not alter meal size or vagal afferent density or structure. However, these mice exhibited modest hyperphagia due to a satiety deficit. In parallel, the possibility that brain-derived neurotrophic factor (BDNF) could mediate APN effects on vagal afferent development was investigated. Brain-derived neurotrophic factor was a strong candidate because APN alters BDNF levels in some tissues and BDNF knockout disrupts development of vagal sensory innervation of the GI tract. Surprisingly, smooth muscle-specific BDNF knockout resulted in early-onset obesity and hyperphagia due to increases in meal size and frequency. Microstructure analysis revealed decreased decay of intake rate during a meal in knockouts, suggesting that the loss of vagal negative feedback contributed to their increase in meal size. However, meal-induced c-Fos activation within the dorsal vagal complex suggested this effect could be due to augmentation of vago-vagal reflexes. A model is proposed to explain how high-fat diet consumption produces increased obesity in organisms exposed to APN, and may be required to reveal effects of EPO on vagal function.
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Affiliation(s)
- Edward A Fox
- Behavioral Neurogenetics Laboratory & Ingestive Behavior Research Center, Department of Psychological Sciences, Purdue University, West Lafayette, IN 47907, USA.
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Zhang LN, Morgan DG, Clapham JC, Speakman JR. Factors predicting nongenetic variability in body weight gain induced by a high-fat diet in inbred C57BL/6J mice. Obesity (Silver Spring) 2012; 20:1179-88. [PMID: 21720432 DOI: 10.1038/oby.2011.151] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Inbred C57BL/6J mice displayed large individual variations in weight gain when fed a high-fat diet (HFD). The objective of this study was to examine whether this predominantly nongenetic variability could be predicted by relevant baseline features and to explore whether variations in these significant features were influenced during pregnancy and/or lactation. Fat mass (FM), fat-free mass (FFM), food intake (FI), resting metabolic rate (RMR), physical activity (PA), and body temperature (T(b)) were all evaluated at baseline in 60 mice (aged 10-12 weeks) before HFD feeding. Regression analyses showed that baseline FM was a strong positive predictor of weight gain between 4 and 16 weeks of HFD. Baseline PA was negatively associated with weight gain at week 8, 12, and 16, and baseline FFM had a positive effect at week 12 and 16. In a second experiment, 40 female mice were mated and litter sizes (LS) were manipulated on day 3 of lactation. Weaning weight and postweaning growth rate (GR) had positive impacts on FM and FFM at age 9 weeks (FM, P = 0.001; FFM, P < 0.001: n = 97). Lactation LS had a negative effect on weaning weight and a positive effect on postweaning GR. In conclusion, our results show that obesity induced by HFD was associated with a higher baseline FM, a higher baseline FFM and a lower baseline PA level before the exposure of HFD. Two of these traits (FM and FFM) were influenced by lactation LS via weaning weight and postweaning GR.
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Affiliation(s)
- Li-Na Zhang
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK
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42
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McAllan L, Cotter PD, Roche HM, Korpela R, Nilaweera KN. Impact of leucine on energy balance. J Physiol Biochem 2012; 69:155-63. [PMID: 22535285 DOI: 10.1007/s13105-012-0170-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 04/10/2012] [Indexed: 12/14/2022]
Abstract
Body weight is determined by the balance between energy intake and energy expenditure. When energy intake exceeds energy expenditure, the surplus energy is stored as fat in the adipose tissue, which causes its expansion and may even lead to the development of obesity. Thus, there is a growing interest to develop dietary interventions that could reduce the current obesity epidemic. In this regard, data from a number of in vivo and in vitro studies suggest that the branched-chain amino acid leucine influences energy balance. However, this has not been consistently reported. Here, we review the literature related to the effects of leucine on energy intake, energy expenditure and lipid metabolism as well as its effects on the cellular activity in the brain (hypothalamus) and in peripheral tissues (gastro-intestinal tract, adipose tissue, liver and muscle) regulating the above physiological processes. Moreover, we discuss how obesity may influence the actions of this amino acid.
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Affiliation(s)
- Liam McAllan
- Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
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43
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Weston-Green K, Huang XF, Deng C. Alterations to melanocortinergic, GABAergic and cannabinoid neurotransmission associated with olanzapine-induced weight gain. PLoS One 2012; 7:e33548. [PMID: 22438946 PMCID: PMC3306411 DOI: 10.1371/journal.pone.0033548] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 02/11/2012] [Indexed: 12/30/2022] Open
Abstract
Background/Aim Second generation antipsychotics (SGAs) are used to treat schizophrenia but can cause serious metabolic side-effects, such as obesity and diabetes. This study examined the effects of low to high doses of olanzapine on appetite/metabolic regulatory signals in the hypothalamus and brainstem to elucidate the mechanisms underlying olanzapine-induced obesity. Methodology/Results Levels of pro-opiomelanocortin (POMC), neuropeptide Y (NPY) and glutamic acid decarboxylase (GAD65, enzyme for GABA synthesis) mRNA expression, and cannabinoid CB1 receptor (CB1R) binding density (using [3H]SR-141716A) were examined in the arcuate nucleus (Arc) and dorsal vagal complex (DVC) of female Sprague Dawley rats following 0.25, 0.5, 1.0 or 2.0 mg/kg olanzapine or vehicle (3×/day, 14-days). Consistent with its weight gain liability, olanzapine significantly decreased anorexigenic POMC and increased orexigenic NPY mRNA expression in a dose-sensitive manner in the Arc. GAD65 mRNA expression increased and CB1R binding density decreased in the Arc and DVC. Alterations to neurotransmission signals in the brain significantly correlated with body weight and adiposity. The minimum dosage threshold required to induce weight gain in the rat was 0.5 mg/kg olanzapine. Conclusions Olanzapine-induced weight gain is associated with reduced appetite-inhibiting POMC and increased NPY. This study also supports a role for the CB1R and GABA in the mechanisms underlying weight gain side-effects, possibly by altering POMC transmission. Metabolic dysfunction can be modelled in the female rat using low, clinically-comparable olanzapine doses when administered in-line with the half-life of the drug.
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Affiliation(s)
- Katrina Weston-Green
- Centre for Translational Neuroscience, School of Health Sciences, University of Wollongong, Wollongong, Australia
- Schizophrenia Research Institute, Darlinghurst, Australia
| | - Xu-Feng Huang
- Centre for Translational Neuroscience, School of Health Sciences, University of Wollongong, Wollongong, Australia
- Schizophrenia Research Institute, Darlinghurst, Australia
| | - Chao Deng
- Centre for Translational Neuroscience, School of Health Sciences, University of Wollongong, Wollongong, Australia
- Schizophrenia Research Institute, Darlinghurst, Australia
- * E-mail:
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Schulz C, Paulus K, Jöhren O, Lehnert H. Intranasal leptin reduces appetite and induces weight loss in rats with diet-induced obesity (DIO). Endocrinology 2012; 153:143-53. [PMID: 22128019 DOI: 10.1210/en.2011-1586] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Resistance to brain-mediated effects of leptin is a characteristic feature of obesity, resulting from alterations in leptin receptor signaling in hypothalamic neurons and/or transport across the blood-brain-barrier. We have shown previously, that the latter can be circumvented by intranasal (i.n.) application of leptin in lean rats. This prompted us to test i.n. leptin in animals with diet-induced obesity (DIO) as a basis for future human administration. DIO was induced in male Wistar rats by feeding a cafeteria diet for 25 or 32 wk, respectively. Consecutively, these DIO animals (seven to eight per treatment) and standard diet rats (lean) (14-15 per treatment, matched for age and diet duration) were treated with 0.1, 0.2 mg/kg leptin, or control solution i.n. daily for 4 wk before onset of dark period. Energy intake and body weight were measured daily; blood glucose, serum insulin, and leptin were measured before and after treatment. Expression of hypothalamic neuropeptides was assessed by quantitative real-time PCR. We demonstrate, for the first time, that i.n. leptin reduces appetite and induces weight loss in DIO to the same extent as in lean rats. Our findings are supported accordingly by an altered expression pattern of anorexigenic and orexigenic neuropeptides in the hypothalamus, e.g. proopiomelanocortin, cocaine and amphetamine-related transcript, neuropeptide Y, agouti-related protein. It now appears clear that i.n. leptin is effectively acting in obese animals in the same fashion as in their lean counterparts. These findings now clearly warrant studies in humans and may open new perspectives in the treatment of obesity.
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Affiliation(s)
- Carla Schulz
- Department of Internal Medicine I, Luebeck University, Ratzeburger Allee 160, 23538 Luebeck, Germany.
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Halpern CH, Torres N, Hurtig HI, Wolf JA, Stephen J, Oh MY, Williams NN, Dichter MA, Jaggi JL, Caplan AL, Kampman KM, Wadden TA, Whiting DM, Baltuch GH. Expanding applications of deep brain stimulation: a potential therapeutic role in obesity and addiction management. Acta Neurochir (Wien) 2011; 153:2293-306. [PMID: 21976235 DOI: 10.1007/s00701-011-1166-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 09/12/2011] [Indexed: 01/01/2023]
Abstract
BACKGROUND The indications for deep brain stimulation (DBS) are expanding, and the feasibility and efficacy of this surgical procedure in various neurologic and neuropsychiatric disorders continue to be tested. This review attempts to provide background and rationale for applying this therapeutic option to obesity and addiction. We review neural targets currently under clinical investigation for DBS—the hypothalamus and nucleus accumbens—in conditions such as cluster headache and obsessive-compulsive disorder. These brain regions have also been strongly implicated in obesity and addiction. These disorders are frequently refractory, with very high rates of weight regain or relapse, respectively, despite the best available treatments. METHODS We performed a structured literature review of the animal studies of DBS, which revealed attenuation of food intake, increased metabolism, or decreased drug seeking. We also review the available radiologic evidence in humans, implicating the hypothalamus and nucleus in obesity and addiction. RESULTS The available evidence of the promise of DBS in these conditions combined with significant medical need, support pursuing pilot studies and clinical trials of DBS in order to decrease the risk of dietary and drug relapse. CONCLUSIONS Well-designed pilot studies and clinical trials enrolling carefully selected patients with obesity or addiction should be initiated.
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Ferretti S, Fornari A, Pedrazzi P, Pellegrini M, Zoli M. Developmental overfeeding alters hypothalamic neuropeptide mRNA levels and response to a high-fat diet in adult mice. Peptides 2011; 32:1371-83. [PMID: 21683751 DOI: 10.1016/j.peptides.2011.06.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 06/01/2011] [Accepted: 06/01/2011] [Indexed: 11/24/2022]
Abstract
It has been suggested that nutritional manipulations during the first weeks of life can alter the development of the hypothalamic circuits involved in energy homeostasis. We studied the expression of a large number of the hypothalamic neuropeptide mRNAs that control body weight in mice that were overfed during breastfeeding (mice grown in a small litter, SL) and/or during adolescence (adolescent mice fed a high-fat diet, AHF). We also investigated possible alterations in mRNA levels after 50 days of a high-fat diet (high-fat challenge, CHF) at 19 weeks of age. Both SL and AHF conditions caused overweight during the period of developmental overfeeding. During adulthood, all of the mouse groups fed a CHF significantly gained weight in comparison with mice fed a low-fat diet, but the mice that had undergone both breast and adolescent overfeeding (SL-AHF-CHF mice) gained significantly more weight than the control CHF mice. Of the ten neuropeptide mRNAs studied, only neuropeptide Y (NPY) expression was decreased in all of the groups of developmentally overfed adult mice, but CHF during adulthood by itself induced a decrease in NPY, agouti-related protein (AgRP) and orexin (Orx) mRNA levels. Moreover, in the developmentally overfed CHF mice NPY, AgRP, galanin (GAL) and galanin-like peptide (GalP) mRNA levels significantly decreased in comparison with the control CHF mice. These results show that, during adulthood, hypothalamic neuropeptide systems are altered (NPY) and/or abnormally respond to a high-fat diet (NPY, AgRP, GAL and GalP) in mice overfed during critical developmental periods.
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Affiliation(s)
- Silvia Ferretti
- Department of Biomedical Sciences, Section of Physiology, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy.
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Ravussin Y, Gutman R, Diano S, Shanabrough M, Borok E, Sarman B, Lehmann A, LeDuc CA, Rosenbaum M, Horvath TL, Leibel RL. Effects of chronic weight perturbation on energy homeostasis and brain structure in mice. Am J Physiol Regul Integr Comp Physiol 2011; 300:R1352-62. [PMID: 21411766 DOI: 10.1152/ajpregu.00429.2010] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Maintenance of reduced body weight in lean and obese human subjects results in the persistent decrease in energy expenditure below what can be accounted for by changes in body mass and composition. Genetic and developmental factors may determine a central nervous system (CNS)-mediated minimum threshold of somatic energy stores below which behavioral and metabolic compensations for weight loss are invoked. A critical question is whether this threshold can be altered by environmental influences and by what mechanisms such alterations might be achieved. We examined the bioenergetic, behavioral, and CNS structural responses to weight reduction of diet-induced obese (DIO) and never-obese (CON) C57BL/6J male mice. We found that weight-reduced (WR) DIO-WR and CON-WR animals showed reductions in energy expenditure, adjusted for body mass and composition, comparable (-10-15%) to those seen in human subjects. The proportion of excitatory synapses on arcuate nucleus proopiomelanocortin neurons was decreased by ∼50% in both DIO-WR and CON-WR mice. These data suggest that prolonged maintenance of an elevated body weight (fat) alters energy homeostatic systems to defend a higher level of body fat. The synaptic changes could provide a neural substrate for the disproportionate decline in energy expenditure in weight-reduced individuals. This response to chronic weight elevation may also occur in humans. The mouse model described here could help to identify the molecular/cellular mechanisms underlying both the defense mechanisms against sustained weight loss and the upward resetting of those mechanisms following sustained weight gain.
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Affiliation(s)
- Y Ravussin
- 1Department of Pediatrics, Division of Molecular Genetics, Columbia University, College of Physicians and Surgeons, New York, New York 10032, USA
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van den Heuvel JK, van Rozen AJ, Adan RAH, la Fleur SE. An overview on how components of the melanocortin system respond to different high energy diets. Eur J Pharmacol 2011; 660:207-12. [PMID: 21211524 DOI: 10.1016/j.ejphar.2010.12.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 11/16/2010] [Accepted: 12/11/2010] [Indexed: 11/27/2022]
Abstract
High energy diets are used to model the obesity epidemic. Moreover, from a variety of genetic studies, it has become clear that the melanocortin system plays an important role in the regulation of energy metabolism. Since most dietary interventions are not standardized, fat/sugar-induced effects on the melanocortin system vary distinctly among different studies. How components of the melanocortin system are affected by high energy diets remains unclear. Therefore, in this review, we first present an overview of the effects of high energy diets on different elements of the melanocortin system in both mice and rats. The effects of a high energy diet are most consistent for agouti related protein levels which were either not affected or decreased after consumption of a high energy diet, whereas for proopiomelanocortin and the melanocortin receptor expression (and binding) it was difficult to define an overall response to a high energy diet. Because of the complexity of the melanocortin system, it is important to measure more than one element of the system. Only a few studies measured both melanocortin peptide and receptor expression and show that a high fat diet consumed for a longer period of time starting at an early age increases melanocortin signaling, whereas in adulthood a very high fat diet decreases melanocortin signaling. Finally, we review our own data on diet-induced changes in peptide expression and melanocortin binding and show that short term exposure to a free-choice high-fat high-sugar diet also decreases melanocortin signaling which supports hyperphagia observed in this model.
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Affiliation(s)
- José K van den Heuvel
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, The Netherlands
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Grayson BE, Levasseur PR, Williams SM, Smith MS, Marks DL, Grove KL. Changes in melanocortin expression and inflammatory pathways in fetal offspring of nonhuman primates fed a high-fat diet. Endocrinology 2010; 151:1622-32. [PMID: 20176722 PMCID: PMC2850229 DOI: 10.1210/en.2009-1019] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The hypothalamic melanocortin system, which controls appetite and energy expenditure, develops during the third trimester in primates. Thus, maternal nutrition and health may have a profound influence on the development of this system. To study the effects of chronic maternal high-fat diet (HFD) on the development of the melanocortin system in the fetal nonhuman primate, we placed adult female macaques on either a control (CTR) diet or a HFD for up to 4 yr. A subgroup of adult female HFD animals was also switched to CTR diet during the fifth year of the study (diet reversal). Third-trimester fetuses from mothers on HFD showed increases in proopiomelanocortin mRNA expression, whereas agouti-related protein mRNA and peptide levels were decreased in comparison with CTR fetuses. Proinflammatory cytokines, including IL-1beta and IL-1 type 1 receptor, and markers of activated microglia were elevated in the hypothalamus, suggesting an activation of the local inflammatory response. Fetuses of diet-reversal mothers had normal melanocortin levels. These results raise the concern that chronic consumption of a HFD during pregnancy, independent of maternal obesity and diabetes, can lead to widespread activation of proinflammatory cytokines that may alter the development of the melanocortin system. The abnormalities in the fetal POMC system, if maintained into the postnatal period, could impact several systems, including body weight homeostasis, stress responses, and cardiovascular function. Indeed, the HFD offspring develop early-onset excess weight gain. These abnormalities may be prevented by healthful nutrient consumption during pregnancy even in obese and severely insulin-resistant individuals.
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Affiliation(s)
- B E Grayson
- Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006, USA
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Swartz TD, Duca FA, Covasa M. Differential feeding behavior and neuronal responses to CCK in obesity-prone and -resistant rats. Brain Res 2009; 1308:79-86. [PMID: 19857467 DOI: 10.1016/j.brainres.2009.10.045] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Revised: 10/15/2009] [Accepted: 10/18/2009] [Indexed: 02/02/2023]
Abstract
Deficits in satiation signals are strongly suspected of accompanying obesity and contributing to its pathogenesis in both humans and rats. One such satiation signal is cholecystokinin (CCK), whose effects on food intake are diminished in animals adapted to a high fat diet. In this study, we tested the hypothesis that diet-induced obese prone (OP) rats exhibit altered feeding and vagal responses to systemic (IP) administration of CCK-8 compared to diet-induced obese resistant (OR) rats. We found that CCK (4.0 microg/kg) suppressed food intake significantly more in OP than OR rats. To determine whether enhanced suppression of feeding is accompanied by altered vagal sensory responsiveness, we examined dorsal hindbrain expression of Fos-like immunoreactivity (Fos-Li) following IP CCK injection in OP and OR rats. After 4.0 microg/kg CCK, there were significantly more Fos-positive nuclei in the NTS of OP compared to OR rats. Treatment with 8.0 microg/kg CCK resulted in no significant difference in food intake or in Fos-Li between OP and OR rats. Also, we found that OP rats were hyperphagic on a regular chow diet and gained more weight compared to OR rats. Finally OP rats had decreased relative fat pad mass compared to OR rats. Collectively, these results show that OP rats exhibit a different behavioral and vagal neuronal responses to CCK than OR rats.
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Affiliation(s)
- T D Swartz
- Interdepartmental Graduate Degree Program in Physiology, Huck Institute of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA
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