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Liu H, Wang G, Zhang J, Lu B, Li D, Chen J. Inhalation of diesel exhaust particulate matter accelerates weight gain via regulation of hypothalamic appetite-related genes and gut microbiota metabolism. JOURNAL OF HAZARDOUS MATERIALS 2024; 466:133570. [PMID: 38309172 DOI: 10.1016/j.jhazmat.2024.133570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 01/17/2024] [Accepted: 01/17/2024] [Indexed: 02/05/2024]
Abstract
Mice exposed to diesel exhaust particulate matter (DEPM) exhibited accelerated weight gain. Several hypothalamic genes, hormones (serum Hypothalamic-Pituitary-Adrenal (HPA) axis hormones and gastrointestinal peptide tyrosine tyrosine (PYY)), metabolites (intrahepatic triglyceride (IHTG) and fecal short-chain fatty acids (SCFAs)), and gut microbiota structure, which may influence obesity and appetite regulation, were examined. The result suggested that DEPM-induced accelerated weight gain may be associated with increased expression of hypothalamic Gamma-aminobutyric acid (GABA) type B receptor, tight junction protein, and orexin receptors, in addition with decreased IHTG and repressed HPA axis. Moreover, changes in the structure of intestinal microbiota are also related to weight changes, especially for phylum Firmicutes, genus Lactobacillus, and the ratio of relative abundance of Firmicutes and Bacteroidetes (F/B). DEPM exposure also caused widespread increase in the levels of intestinal SCFAs, the concentrations of propionic acid and isobutyric acid were associated with weight gain rate and the abundance of some bacteria. Although DEPM exposure caused changes in expression of hypothalamic serotonin, NPY, and melanocortin receptors, they were not associated with weight changes. Furthermore, no significant difference in gastrointestinal PYY and expression of hypothalamic receptors for leptin, insulin, and glucagon-like peptide 1 receptors was observed between DEPM-exposed and control mice.
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Affiliation(s)
- Hou Liu
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Guicheng Wang
- Institute of Developmental Biology and Molecular Medicine, Fudan University, Shanghai 200433, China
| | - Jin Zhang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Bingjie Lu
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Dan Li
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
| | - Jianmin Chen
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
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Neuroendocrine control of appetite and metabolism. Exp Mol Med 2021; 53:505-516. [PMID: 33837263 PMCID: PMC8102538 DOI: 10.1038/s12276-021-00597-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 02/11/2021] [Accepted: 02/17/2021] [Indexed: 02/02/2023] Open
Abstract
Body homeostasis is predominantly controlled by hormones secreted by endocrine organs. The central nervous system contains several important endocrine structures, including the hypothalamic-pituitary axis. Conventionally, neurohormones released by the hypothalamus and the pituitary gland (hypophysis) have received much attention owing to the unique functions of the end hormones released by their target peripheral organs (e.g., glucocorticoids released by the adrenal glands). Recent advances in mouse genetics have revealed several important metabolic functions of hypothalamic neurohormone-expressing cells, many of which are not readily explained by the action of the corresponding classical downstream hormones. Notably, the newly identified functions are better explained by the action of conventional neurotransmitters (e.g., glutamate and GABA) that constitute a neuronal circuit. In this review, we discuss the regulation of appetite and metabolism by hypothalamic neurohormone-expressing cells, with a focus on the distinct contributions of neurohormones and neurotransmitters released by these neurons.
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Rowland NE, Toth LA. Analytic and Interpretational Pitfalls to Measuring Fecal Corticosterone Metabolites in Laboratory Rats and Mice. Comp Med 2019; 69:337-349. [PMID: 31578162 DOI: 10.30802/aalas-cm-18-000119] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Minimization and alleviation of stress are generally viewed as desirable aspects of laboratory animal management and use. However, achieving that goal requires an unambiguous and valid measure of stress. Glucocorticoid concentrations are commonly used as a physiologic index of stress. Measurement of glucocorticoids in blood, serum or plasma clearly reflects many types of both acute and chronic stress. However, the rapid rise in concentrations of circulating glucocorticoids that occurs even with relatively simple manipulations such as handling has led to the increased use of fecal glucocorticoid metabolite (FCM) assays, which provide a temporally integrated measure that may allow a more accurate interpretation of chronic stressors. In this review, we consider 3 aspects of glucocorticoids as a measure of stress. First, we discuss the analytic and interpretational pitfalls of using FCM concentrations as an index of stress in mice and rats. Second, we consider evidence that some degree of stress may benefit animals by priming physiologic and behavioral adaptations that render the animals more resilient in the face of stress. Finally, we use 2 situations-social housing and food restriction-to illustrate the concept of hormesis-a biologic phenomenon in which a low dose or intensity of a challenge has a beneficial effect, whereas exposure to high doses or intensities is detrimental.
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Affiliation(s)
- Neil E Rowland
- Department of Psychology, University of Florida, Gainesville, Florida;,
| | - Linda A Toth
- Department of Pharmacology, School of Medicine, Southern Illinois University, Springfield, Illinois
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Yadawa AK, Richa R, Chaturvedi CM. Herbicide Paraquat provokes the stress responses of HPA axis of laboratory mouse, Mus musculus. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2019; 153:106-115. [PMID: 30744883 DOI: 10.1016/j.pestbp.2018.11.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 10/02/2018] [Accepted: 11/08/2018] [Indexed: 06/09/2023]
Abstract
Paraquat (PQ) is a herbicide and well characterized pneumotoxicant which is also known to induce neurodegeneration in organisms. Aim of this study was to investigate the effect of PQ on hypothalamic - pituitary - adrenal (HPA) axis. PQ was administered i.p.10 mg/kg body weight once a week for 5 weeks in laboratory male mice. Results indicate that SOD activity decreased while catalase activity and nitrate-nitrite level increased significantly in the hypothalamus of PQ treated mice. The expression of both AVP and CRH mRNA in the hypothalamus as well as ir-AVP and ir-CRH increased in the PVN of PQ treated mice compared to control. Immunoreactivity of nNOS and Hsp70 including NF-κB mRNA expression increased in the PVN of PQ treated mice. As expected, serum corticosterone level was also elevated significantly in the herbicide PQ treated mice. From these findings it is concluded that paraquat treatment is capable of activating the HPA axis via upregulating transcription and translation of the hypothalamic neuropeptides AVP and CRH as well as serum corticosterone level. Increase in both oxidative and nitrosative stress in PQ treated mice might be the driver which also contributed to the activation of HPA axis. It seems that stress induced reactive species (ROS, RNS) might be also responsible for the induced expression of NF-κB mRNA and Hsp70 protein which are considered as the reliable markers of certain types of stressors including PQ toxicity.
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Affiliation(s)
- Arun Kumar Yadawa
- Department of Zoology, Banaras Hindu University, Varanasi 221005, India
| | - Rashmi Richa
- Department of Zoology, Banaras Hindu University, Varanasi 221005, India
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5
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Yadawa AK, Chaturvedi CM. Expression of stress hormones AVP and CRH in the hypothalamus of Mus musculus following water and food deprivation. Gen Comp Endocrinol 2016; 239:13-20. [PMID: 26965951 DOI: 10.1016/j.ygcen.2016.03.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 02/04/2016] [Accepted: 03/05/2016] [Indexed: 01/24/2023]
Abstract
Neurohypophyseal hormone, arginine vasopressin (AVP), in addition to acting as antidiuretic hormone is also considered to be stress hormone like hypothalamic corticotropin-releasing hormone (CRH). Present study was designed to investigate the relative response of these stress hormones during water and food deprivation. In this study, male laboratory mice of Swiss strain were divided in 5 groups, control - provided water and food ad libitum, two experimental groups water deprived for 2 and 4days respectively (WD2 and WD4) and another two groups food deprived for 2 and 4days respectively (FD2 and FD4). Results indicate an increased expression of AVP mRNA as well as peptide in the hypothalamus of WD2 mice and the expression was further upregulated after 4days of water deprivation but the expression of CRH remained unchanged compare to their respective controls. On the other hand no change was observed in the expression of hypothalamic AVP mRNA while AVP peptide increased significantly in FD2 and FD4 mice compare to control. Further, the expression of CRH mRNA although increased in hypothalamus of both FD2 and FD4 mice, the immunofluorescent staining shows decreased expression of CRH in PVN of food deprived mice. Based on these findings it is concluded that since during osmotic stress only AVP expression is upregulated but during metabolic stress i.e. food deprivation transcription and translation of both the stress hormones are differentially regulated. Further, it is suggested that role of AVP and CRH may be stress specific.
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Affiliation(s)
- Arun Kumar Yadawa
- Department of Zoology, Banaras Hindu University, Varanasi 221005, India
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A potent and selective 11β-hydroxysteroid dehydrogenase type 1 inhibitor, SKI2852, ameliorates metabolic syndrome in diabetic mice models. Eur J Pharmacol 2015; 768:139-48. [PMID: 26519792 DOI: 10.1016/j.ejphar.2015.10.042] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 10/22/2015] [Accepted: 10/26/2015] [Indexed: 11/22/2022]
Abstract
11β-Hydroxysteroid dehydrogenase type 1 (11βHSD1) has been targeted for new drugs to treat type 2 diabetes and metabolic syndrome. In this study, we determined whether the inhibition of 11βHSD1 with a new selective inhibitor, SKI2852, could improve lipid profiles, glucose levels, and insulin sensitivity in type 2 diabetic and obese conditions. SKI2852 showed a potent inhibition of cortisone to cortisol conversion for over 80% in both liver and adipose tissue ex vivo from orally administered C57BL/6 mice, and in vivo analysis results were consistent with this. Repeated oral administrations of SKI2852 in diet-induced obesity (DIO) and ob/ob mice revealed a partially beneficial effect of SKI2852 in improving levels of cholesterols, triglycerides, free fatty acids, postprandial glucose, and/or blood hemoglobinA1c. SKI2852 significantly reduced body weight increase in ob/ob mice, and efficiently suppressed hepatic mRNA levels of gluconeogenic enzymes in DIO mice. Moreover, SKI2852 enhanced hepatic and whole body insulin sensitivities in hyperinsulinemic-euglycemic clamp experiment in DIO mice. In conclusion, these results indicate that selective and potent inhibition of 11βHSD1 by SKI2852, thus blockade of active glucocorticoid conversion, may improve many aspects of metabolic parameters in type 2 diabetes and metabolic diseases, mainly by inhibitions of hepatic gluconeogenesis and partial improvements of lipid profiles. Our study strongly support that SKI2852 may have a great potential as a novel candidate drug for the treatment of diabetes and metabolic diseases.
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Hao K, Kong FP, Gao YQ, Tang JW, Chen J, Evans AM, Lightman SL, Chen XQ, Du JZ. Inactivation of corticotropin-releasing hormone-induced insulinotropic role by high-altitude hypoxia. Diabetes 2015; 64:785-95. [PMID: 25277397 DOI: 10.2337/db14-0500] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We have shown that hypoxia reduces plasma insulin, which correlates with corticotropin-releasing hormone (CRH) receptor 1 (CRHR1) in rats, but the mechanism remains unclear. Here, we report that hypobaric hypoxia at an altitude of 5,000 m for 8 h enhances rat plasma CRH, corticosterone, and glucose levels, whereas the plasma insulin and pancreatic ATP/ADP ratio is reduced. In islets cultured under normoxia, CRH stimulated insulin release in a glucose- and CRH-level-dependent manner by activating CRHR1 and thus the cAMP-dependent protein kinase pathway and calcium influx through L-type channels. In islets cultured under hypoxia, however, the insulinotropic effect of CRH was inactivated due to reduced ATP and cAMP and coincident loss of intracellular calcium oscillations. Serum and glucocorticoid-inducible kinase 1 (SGK1) also played an inhibitory role. In human volunteers rapidly ascended to 3,860 m, plasma CRH and glucose levels increased without a detectable change in plasma insulin. By contrast, volunteers with acute mountain sickness (AMS) exhibited a marked decrease in HOMA insulin sensitivity (HOMA-IS) and enhanced plasma CRH. In conclusion, hypoxia may attenuate the CRH-insulinotropic effect by reducing cellular ATP/ADP ratio, cAMP and calcium influx, and upregulated SGK1. Hypoxia may not affect HOMA-IS in healthy volunteers but reduces it in AMS volunteers.
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Affiliation(s)
- Ke Hao
- Division of Neurobiology and Physiology, Department of Basic Medical Sciences, School of Medicine, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University, Hangzhou, China
| | - Fan-Ping Kong
- Division of Neurobiology and Physiology, Department of Basic Medical Sciences, School of Medicine, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University, Hangzhou, China
| | - Yu-Qi Gao
- Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China
| | - Jia-Wei Tang
- Division of Neurobiology and Physiology, Department of Basic Medical Sciences, School of Medicine, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University, Hangzhou, China
| | - Jian Chen
- Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China
| | - A Mark Evans
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, U.K
| | - Stafford L Lightman
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol, U.K
| | - Xue-Qun Chen
- Division of Neurobiology and Physiology, Department of Basic Medical Sciences, School of Medicine, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University, Hangzhou, China
| | - Ji-Zeng Du
- Division of Neurobiology and Physiology, Department of Basic Medical Sciences, School of Medicine, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University, Hangzhou, China
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Wu JW, Wang SP, Casavant S, Moreau A, Yang GS, Mitchell GA. Fasting energy homeostasis in mice with adipose deficiency of desnutrin/adipose triglyceride lipase. Endocrinology 2012; 153:2198-207. [PMID: 22374972 DOI: 10.1210/en.2011-1518] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Adipose triglyceride lipase (ATGL) catalyzes the first step of lipolysis of cytoplasmic triacylglycerols in white adipose tissue (WAT) and several other organs. We created adipose-specific ATGL-deficient (ATGLAKO) mice. In these mice, in vivo lipolysis, measured as the increase of plasma nonesterified fatty acid and glycerol levels after injection of a β3-adrenergic agonist, was undetectable. In isolated ATGLAKO adipocytes, β3-adrenergic-stimulated glycerol release was 10-fold less than in controls. Under fed conditions, ATGLAKO mice had normal viability, mild obesity, low plasma nonesterified fatty acid levels, increased insulin sensitivity, and increased daytime food intake. After 5 h of fasting, ATGLAKO WAT showed phosphorylation of the major protein kinase A-mediated targets hormone-sensitive lipase and perilipin A and ATGLAKO liver showed low glycogen and triacylglycerol contents. During a 48-h fast, ATGLAKO mice developed striking and complex differences from controls: progressive reduction of oxygen consumption, high respiratory exchange ratio, consistent with reduced fatty acid availability for energy production, lethargy, hypothermia, and undiminished fat mass, but greater loss of lean mass than controls. Plasma of 48 h-fasted ATGLAKO mice had a unique pattern: low 3-hydroxybutyrate, insulin, adiponectin, and fibroblast growth factor 21 with elevated leptin and corticosterone. ATGLAKO WAT, liver, skeletal muscle, and heart showed increased levels of mRNA related to autophagy and proteolysis. In murine ATGL deficiency, adipose lipolysis is critical for fasting energy homeostasis, and fasting imposes proteolytic stress on many organs, including heart and skeletal muscle.
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Affiliation(s)
- Jiang Wei Wu
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and Centre Hospitalier Universitaire Sainte-Justine, 3175 Côte-Sainte-Catherine, Montréal, Québec, Canada
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9
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Modulation of pancreatic islets-stress axis by hypothalamic releasing hormones and 11beta-hydroxysteroid dehydrogenase. Proc Natl Acad Sci U S A 2011; 108:13722-7. [PMID: 21825133 DOI: 10.1073/pnas.1110965108] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Corticotropin-releasing hormone (CRH) and growth hormone-releasing hormone (GHRH), primarily characterized as neuroregulators of the hypothalamic-pituitary-adrenal axis, directly influence tissue-specific receptor-systems for CRH and GHRH in the endocrine pancreas. Here, we demonstrate the expression of mRNA for CRH and CRH-receptor type 1 (CRHR1) and of protein for CRHR1 in rat and human pancreatic islets and rat insulinoma cells. Activation of CRHR1 and GHRH-receptor significantly increased cell proliferation and reduced cell apoptosis. CRH stimulated both cellular content and release of insulin in rat islet and insulinoma cells. At the ultrastructural level, CRHR1 stimulation revealed a more active metabolic state with enlarged mitochondria. Moreover, glucocorticoids that promote glucose production are balanced by both 11b-hydroxysteroid dehydrogenase (11β-HSD) isoforms; 11β-HSD-type-1 and 11β-HSD-type-2. We demonstrated expression of mRNA for 11β-HSD-1 and 11β-HSD-2 and protein for 11β-HSD-1 in rat and human pancreatic islets and insulinoma cells. Quantitative real-time PCR revealed that stimulation of CRHR1 and GHRH-receptor affects the metabolism of insulinoma cells by down-regulating 11β-HSD-1 and up-regulating 11β-HSD-2. The 11β-HSD enzyme activity was analyzed by measuring the production of cortisol from cortisone. Similarly, activation of CRHR1 resulted in reduced cortisol levels, indicating either decreased 11β-HSD-1 enzyme activity or increased 11β-HSD-2 enzyme activity; thus, activation of CRHR1 alters the glucocorticoid balance toward the inactive form. These data indicate that functional receptor systems for hypothalamic-releasing hormone agonists exist within the endocrine pancreas and influence synthesis of insulin and the pancreatic glucocorticoid shuttle. Agonists of CRHR1 and GHRH-receptor, therefore, may play an important role as novel therapeutic tools in the treatment of diabetes mellitus.
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Alon T, Zhou L, Pérez CA, Garfield AS, Friedman JM, Heisler LK. Transgenic mice expressing green fluorescent protein under the control of the corticotropin-releasing hormone promoter. Endocrinology 2009; 150:5626-32. [PMID: 19854866 PMCID: PMC2795705 DOI: 10.1210/en.2009-0881] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CRH is widely expressed in the brain and is of broad functional relevance to a number of physiological processes, including stress response, parturition, immune response, and ingestive behavior. To delineate further the organization of the central CRH network, we generated mice expressing green fluorescent protein (GFP) under the control of the CRH promoter, using bacterial artificial chromosome technology. Here we validate CRH-GFP transgene expression within specific brain regions and confirm the distribution of central GFP-producing cells to faithfully recapitulate that of CRH-expressing cells. Furthermore, we confirm the functional integrity of a population of GFP-producing cells by demonstrating their opposite responsiveness to nutritional status. We anticipate that this transgenic model will lend itself as a highly tractable tool for the investigation of CRH expression and function in discrete brain regions.
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Affiliation(s)
- Tamar Alon
- Laboratory of Molecular Genetics and Howard Hughes Medical Institute, Rockefeller University, New York, New York 10065, USA
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11
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Kawashima S, Sakihara S, Kageyama K, Nigawara T, Suda T. Corticotropin-releasing factor (CRF) is involved in the acute anorexic effect of alpha-melanocyte-stimulating hormone: a study using CRF-deficient mice. Peptides 2008; 29:2169-74. [PMID: 18930089 DOI: 10.1016/j.peptides.2008.09.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Revised: 09/16/2008] [Accepted: 09/18/2008] [Indexed: 01/08/2023]
Abstract
Alpha-melanocyte-stimulating hormone (alpha-MSH) and its receptors are critical and indispensable for maintaining appropriate feeding behavior and energy homeostasis in both mice and humans. Corticotropin-releasing factor (CRF) is a candidate for mediating the anorexic effect of alpha-MSH. In the present study, we examined whether CRF and its receptors are involved in the anorexic effect of alpha-MSH, using CRF-deficient (CRFKO) mice and a CRF receptor antagonist. Intracerebroventricular administration of NDP-MSH, a synthetic alpha-MSH analogue, suppressed food intake in wild-type (WT) mice. This effect was abolished by pretreatment with a non-selective CRF receptor antagonist, astressin, suggesting that the effect of alpha-MSH-induced anorexia was mediated by a CRF receptor. In CRFKO mice, administration with NDP-MSH did not affect food intake at an early phase (0-4h). In addition, CRF mRNA levels in the hypothalamus were significantly increased in NDP-MSH-treated mice. Therefore, our findings, using CRFKO, strongly support evidence that CRF is involved in the acute anorexic effect of alpha-MSH. On the other hand, NDP-MSH administered to CRFKO mice led to suppressed food intake at the late phase (4-12h), similar to the effect in WT mice. Further, NDP-MSH similarly reduced food intake during the late phase in all types of mice, including WT, CRFKO, and CRFKO with corticosterone replacement. The results would suggest that alpha-MSH-induced suppression of food intake at late phase was independent of glucocorticoids and CRF.
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Affiliation(s)
- Shoko Kawashima
- Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori 036-8562, Japan
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Willie JT, Sinton CM, Maratos-Flier E, Yanagisawa M. Abnormal response of melanin-concentrating hormone deficient mice to fasting: hyperactivity and rapid eye movement sleep suppression. Neuroscience 2008; 156:819-29. [PMID: 18809470 DOI: 10.1016/j.neuroscience.2008.08.048] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 08/20/2008] [Accepted: 08/22/2008] [Indexed: 10/21/2022]
Abstract
Melanin-concentrating hormone (MCH) is a hypothalamic neuropeptide that has been implicated in energy homeostasis. Pharmacological studies with MCH and its receptor antagonists have suggested additional behavioral roles for the neuropeptide in the control of mood and vigilance states. These suggestions have been supported by a report of modified sleep in the MCH-1 receptor knockout mouse. Here we found that MCH knockout (MCH(-)(/)(-)) mice slept less during both the light and dark phases under baseline conditions. In response to fasting, MCH(-)(/)(-) mice exhibited marked hyperactivity, accelerated weight loss and an exaggerated decrease in rapid eye movement (REM) sleep. Following a 6-h period of sleep deprivation, however, the sleep rebound in MCH(-)(/)(-) mice was normal. Thus MCH(-)(/)(-) mice adapt poorly to fasting, and their loss of bodyweight under this condition is associated with behavioral hyperactivity and abnormal expression of REM sleep. These results support a role for MCH in vigilance state regulation in response to changes in energy homeostasis and may relate to a recent report of initial clinical trials with a novel MCH-1 receptor antagonist. When combined with caloric restriction, the treatment of healthy, obese subjects with this compound resulted in some subjects experiencing vivid dreams and sleep disturbances.
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Affiliation(s)
- J T Willie
- Department of Molecular Genetics, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-8584, USA
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Zarate J, Churruca I, Echevarría E, Casis L, López de Jesús M, Saenz del Burgo L, Sallés J. Immunohistochemical localization of CB1 cannabinoid receptors in frontal cortex and related limbic areas in obese Zucker rats: effects of chronic fluoxetine treatment. Brain Res 2008; 1236:57-72. [PMID: 18722357 DOI: 10.1016/j.brainres.2008.07.100] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Revised: 07/17/2008] [Accepted: 07/18/2008] [Indexed: 11/17/2022]
Abstract
In the present study, we report on the application of two specific polyclonal antibodies to different intracellular domains of the CB1 cannabinoid receptor to define the expression of the neural CB1 cannabinoid receptor at the histochemical level in frontal cortex and related limbic areas of the obese Zucker rats. Higher levels of CB1 receptor expression in frontal, cingulated and piriform cortex, without differences in temporal, parietal and occipital cortex, were observed in obese Zucker rats, with respect to their lean littermates. CB1 phosphorylated receptor (CB1-P) levels were also higher in frontal, temporal, parietal and occipital cortex in obese rats with respect to lean controls. Potential involvement of brain cortical CB1 cannabinoid receptors in the long-term effects of fluoxetine was studied. Experimental animals were administered with fluoxetine (10 mg/kg, i.p.) daily for 3 weeks, whereas the control group was given 0.9% NaCl solution. In obese Zucker rats, a significant decrease in CB1 receptor levels, measured by western blot, was observed in brain cortex after fluoxetine treatment. Immunostaining for CB1 receptor expression was also carried out, showing a significant decrease in the density of neural cells positive for CB1 receptor in frontal, cingulate and piriform cortex, without changes in parietal, temporal and occipital regions. Regional prosencephalic immunostaining for CB1-P receptor level showed a significant decrease in the density of stained neural cells in frontal, temporal and parietal cortex, without changes in cingulated, piriform and occipital cortex. These results suggest the involvement of endocannabinoid system in the chronic effects of fluoxetine, especially in the frontal cortex.
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Affiliation(s)
- J Zarate
- Department of Physiology, Faculty of Pharmacy, University of the Basque Country, Paseo de la Universidad 7, 01006 Vitoria, Spain
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Gay J, Kokkotou E, O'Brien M, Pothoulakis C, Karalis KP. Corticotropin-releasing hormone deficiency is associated with reduced local inflammation in a mouse model of experimental colitis. Endocrinology 2008; 149:3403-9. [PMID: 18403481 PMCID: PMC2453096 DOI: 10.1210/en.2007-1703] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
CRH, the hypothalamic component of the hypothalamic-pituitary adrenal axis, attenuates inflammation through stimulation of glucocorticoid release, whereas peripherally expressed CRH acts as a proinflammatory mediator. CRH is expressed in the intestine and up-regulated in patients with ulcerative colitis. However, its pathophysiological significance in intestinal inflammatory diseases has just started to emerge. In a mouse model of acute, trinitrobenzene sulfonic acid-induced experimental colitis, we demonstrate that, despite low glucocorticoid levels, CRH-deficient mice develop substantially reduced local inflammatory responses. These effects were shown by histological scoring of tissue damage and neutrophil infiltration. At the same time, CRH deficiency was found to be associated with higher serum leptin and IL-6 levels along with sustained anorexia and weight loss, although central CRH has been reported to be a strong appetite suppressor. Taken together, our results support an important proinflammatory role for CRH during mouse experimental colitis and possibly in inflammatory bowel disease in humans. Moreover, the results suggest that CRH is involved in homeostatic pathways that link inflammation and metabolism.
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Affiliation(s)
- Jérôme Gay
- Division of Endocrinology, Children's Hospital, Boston, MA 02215, USA
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Girard I, Rezende EL, Garland T. Leptin levels and body composition of mice selectively bred for high voluntary locomotor activity. Physiol Biochem Zool 2007; 80:568-79. [PMID: 17909994 DOI: 10.1086/521086] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/06/2007] [Indexed: 11/03/2022]
Abstract
Selective breeding produced four replicate lines of high-runner (HR) mice that run on wheels for approximately 2.7 times more revolutions per day than four unselected control lines. Previous studies found that HR mice of both sexes have lower body fat (isotope dilution at 15 wk of age) and that males (females not studied) have smaller retroperitoneal fat pads (17 wk). HR mice also exhibit elevated plasma corticosterone and insulin-stimulated glucose uptake by some hindlimb muscles but apparently do not differ in circulating insulin or glucose levels (males at 18 wk). Given their lower body fat and higher activity levels, we hypothesized that HR mice would have lower circulating leptin levels than controls. Female mice were given wheel access for 6 d at 7 wk of age, as part of the routine wheel testing for the selective breeding protocol, and then were killed after one additional week without wheels to reduce possible acute effects of activity on leptin. As hypothesized, serum leptin levels were significantly lower in HR mice. ANCOVA indicated that leptin was strongly positively correlated with both total body fat (measured by ether extraction) and body mass change from weaning, but HR mice still had significantly lower adjusted leptin levels (ANCOVA). Within HR lines but not within control lines, individual variation in leptin levels was negatively correlated with amount or speed of wheel running measured a week before being killed. Growth from weaning to euthanasia and body dry mass were lower in HR mice than in controls, but absolute dry masses of the ventricles, liver, gut, and uterus plus ovaries did not significantly differ, nor did percentage of the total dry mass as fat. HR mice offer a novel model for studying the causes and consequences of physiologically relevant variations in serum leptin.
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Affiliation(s)
- Isabelle Girard
- Department of Biology, University of Wisconsin, 800 Reserve Street, Stevens Point, Wisconsin 54481, USA
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Teli T, Xanthaki D, Karalis KP. Regulation of appetite and insulin signaling in inflammatory states. Ann N Y Acad Sci 2007; 1083:319-28. [PMID: 17148747 DOI: 10.1196/annals.1367.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Inflammatory states are characterized by decreased food intake, hyperglycemia, and insulin resistance. The contribution of cytokines in this phenotype is important and is exerted through activation of SOCS proteins and inhibition of insulin signaling, as well as through direct stimulation of the ob gene. Obesity, a condition that has reached epidemic rates, is characterized by hyperglycemia, hyperlipidemia, insulin resistance and increased food intake, and body weight. In the following article we summarize the current views of the mechanisms underlying insulin resistance in obesity and the other inflammatory states. We also discuss the regulation of appetite in inflammatory states, and we provide evidence on the cytokine-independent induction of anorexia following immune activation in mice. Understanding of the exact mechanisms regulating these processes may provide important insights for the control of this group of diseases that compromise to a great extent the quality of life and are associated with high mortality.
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Affiliation(s)
- Thalia Teli
- Developmental Biology Section, Foundation for Biomedical Research of the Academy of Athens, Athens, 11527 Greece
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Malendowicz LK, Rucinski M, Belloni AS, Ziolkowska A, Nussdorfer GG. Leptin and the regulation of the hypothalamic-pituitary-adrenal axis. INTERNATIONAL REVIEW OF CYTOLOGY 2007; 263:63-102. [PMID: 17725965 DOI: 10.1016/s0074-7696(07)63002-2] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Leptin, the product of the obesity gene (ob) predominantly secreted from adipocytes, plays a major role in the negative control of feeding and acts via a specific receptor (Ob-R), six isoforms of which are known at present. Evidence has been accumulated that leptin, like other peptides involved in the central regulation of food intake, controls the function of the hypothalamic-pituitary-adrenal (HPA) axis, acting on both its central and peripheral branches. Leptin, along with Ob-R, is expressed in the hypothalamus and pituitary gland, where it modulates corticotropin-releasing hormone and ACTH secretion, probably acting in an autocrine-paracrine manner. Only Ob-R is expressed in the adrenal gland, thereby making it likely that leptin affects it by acting as a circulating hormone. Although in vitro and in vivo findings could suggest a glucocorticoid secretagogue action in the rat, the bulk of evidence indicates that leptin inhibits steroid-hormone secretion from the adrenal cortex. In keeping with this, leptin was found to dampen the HPA axis response to many kinds of stress. In contrast, leptin enhances catecolamine release from the adrenal medulla. This observation suggests that leptin activates the sympathoadrenal axis and does not appear to agree with its above-mentioned antistress action. Leptin and/or Ob-R are also expressed in pituitary and adrenal tumors, but little is known about the role of this cytokine in the pathophysiology.
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Affiliation(s)
- Ludwik K Malendowicz
- Department of Histology and Embryology, School of Medicine, Karol Marcinkowski University of Medical Sciences, PL-60781 Poznan, Poland
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Malcher-Lopes R, Di S, Marcheselli VS, Weng FJ, Stuart CT, Bazan NG, Tasker JG. Opposing crosstalk between leptin and glucocorticoids rapidly modulates synaptic excitation via endocannabinoid release. J Neurosci 2006; 26:6643-50. [PMID: 16775153 PMCID: PMC6674033 DOI: 10.1523/jneurosci.5126-05.2006] [Citation(s) in RCA: 190] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The hypothalamic paraventricular nucleus (PVN) integrates preautonomic and neuroendocrine control of energy homeostasis, fluid balance, and the stress response. We recently demonstrated that glucocorticoids act via a membrane receptor to rapidly cause endocannabinoid-mediated suppression of synaptic excitation in PVN neurosecretory neurons. Leptin, a major signal of nutritional state, suppresses CB(1) cannabinoid receptor-dependent hyperphagia (increased appetite) in fasting animals by reducing hypothalamic levels of endocannabinoids. Here we show that glucocorticoids stimulate endocannabinoid biosynthesis and release via a Galpha(s)-cAMP-protein kinase A-dependent mechanism and that leptin blocks glucocorticoid-induced endocannabinoid biosynthesis and suppression of excitation in the PVN via a phosphodiesterase-3B-mediated reduction in intracellular cAMP levels. We demonstrate this rapid hormonal interaction in both PVN magnocellular and parvocellular neurosecretory cells. Leptin blockade of the glucocorticoid-induced, endocannabinoid-mediated suppression of excitation was absent in leptin receptor-deficient obese Zucker rats. Our findings reveal a novel hormonal crosstalk that rapidly modulates synaptic excitation via endocannabinoid release in the hypothalamus and that provides a nutritional state-sensitive mechanism to integrate the neuroendocrine regulation of energy homeostasis, fluid balance, and the stress response.
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Abstract
Leptin influences satiety, adiposity, and metabolism and is associated with mechanisms regulating puberty onset, fertility, and pregnancy in various species. Maternal hyperleptinemia is a hallmark of mammalian pregnancy, although both the roles of leptin and the mechanisms regulating its synthesis appear to be taxa specific. In pregnant humans and nonhuman primates, leptin is produced by both maternal and fetal adipose tissues, as well as by the placental trophoblast. Specific receptors in the uterine endometrium, trophoblast, and fetus facilitate direct effects of the polypeptide on implantation, placental endocrine function, and conceptus development. A soluble isoform of the receptor may be responsible for inducing maternal leptin resistance during pregnancy and/or may facilitate the transplacental passage of leptin for the purpose of directly regulating fetal development. The steroid hormones are linked to the regulation of leptin and the leptin receptor and probably interact with other pregnancy-specific, serum-borne factors to regulate leptin dynamics during pregnancy. In addition to its effects on normal conceptus development, leptin is linked to mechanisms affecting a diverse array of pregnancy-specific pathologies that include preeclampsia, gestational diabetes, and intrauterine growth restriction. Association with these anomalies and with mechanisms pointing to a fetal origin for a range of conditions affecting the individual's health in adult life, such as obesity, diabetes mellitus, and cardiovascular disease, reiterate the need for continued research dedicated to elucidating leptin's roles and regulation throughout gestation.
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Affiliation(s)
- Michael C Henson
- Department of Obstetrics and Gynecology, Tulane University Health Sciences Center, New Orleans, Louisiana 70112-2699, USA.
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