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Nilsson A, Wilhelms DB, Mirrasekhian E, Jaarola M, Blomqvist A, Engblom D. Inflammation-induced anorexia and fever are elicited by distinct prostaglandin dependent mechanisms, whereas conditioned taste aversion is prostaglandin independent. Brain Behav Immun 2017; 61:236-243. [PMID: 27940259 PMCID: PMC5325121 DOI: 10.1016/j.bbi.2016.12.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 11/28/2016] [Accepted: 12/05/2016] [Indexed: 02/07/2023] Open
Abstract
Systemic inflammation evokes an array of brain-mediated responses including fever, anorexia and taste aversion. Both fever and anorexia are prostaglandin dependent but it has been unclear if the cell-type that synthesizes the critical prostaglandins is the same. Here we show that pharmacological inhibition or genetic deletion of cyclooxygenase (COX)-2, but not of COX-1, attenuates inflammation-induced anorexia. Mice with deletions of COX-2 selectively in brain endothelial cells displayed attenuated fever, as demonstrated previously, but intact anorexia in response to peripherally injected lipopolysaccharide (10μg/kg). Whereas intracerebroventricular injection of a cyclooxygenase inhibitor markedly reduced anorexia, deletion of COX-2 selectively in neural cells, in myeloid cells or in both brain endothelial and neural cells had no effect on LPS-induced anorexia. In addition, COX-2 in myeloid and neural cells was dispensable for the fever response. Inflammation-induced conditioned taste aversion did not involve prostaglandin signaling at all. These findings collectively show that anorexia, fever and taste aversion are triggered by distinct routes of immune-to-brain signaling.
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Affiliation(s)
- Anna Nilsson
- Department of Clinical and Experimental Medicine, Linköping University, Sweden
| | - Daniel Björk Wilhelms
- Department of Clinical and Experimental Medicine, Linköping University, Sweden,Department of Emergency Medicine, Linköping University, Linköping, Sweden
| | - Elahe Mirrasekhian
- Department of Clinical and Experimental Medicine, Linköping University, Sweden
| | - Maarit Jaarola
- Department of Clinical and Experimental Medicine, Linköping University, Sweden
| | - Anders Blomqvist
- Department of Clinical and Experimental Medicine, Linköping University, Sweden
| | - David Engblom
- Department of Clinical and Experimental Medicine, Linköping University, Sweden.
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3
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Liu Y, Huang Y, Liu T, Wu H, Cui H, Gautron L. Lipopolysacharide Rapidly and Completely Suppresses AgRP Neuron-Mediated Food Intake in Male Mice. Endocrinology 2016; 157:2380-92. [PMID: 27111742 PMCID: PMC4891783 DOI: 10.1210/en.2015-2081] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Although Agouti-related peptide (AgRP) neurons play a key role in the regulation of food intake, their contribution to the anorexia caused by proinflammatory insults has yet to be identified. Using a combination of neuroanatomical and pharmacogenetics experiments, this study sought to investigate the importance of AgRP neurons and downstream targets in the anorexia caused by the peripheral administration of a moderate dose of lipopolysaccharide (LPS) (100 μg/kg, ip). First, in the C57/Bl6 mouse, we demonstrated that LPS induced c-fos in select AgRP-innervated brain sites involved in feeding but not in any arcuate proopiomelanocortin neurons. Double immunohistochemistry further showed that LPS selectively induced c-Fos in a large subset of melanocortin 4 receptor-expressing neurons in the lateral parabrachial nucleus. Secondly, we used pharmacogenetics to stimulate the activity of AgRP neurons during the course of LPS-induced anorexia. In AgRP-Cre mice expressing the designer receptor hM3Dq-Gq only in AgRP neurons, the administration of the designer drug clozapine-N-oxide (CNO) induced robust food intake. Strikingly, CNO-mediated food intake was rapidly and completely blunted by the coadministration of LPS. Neuroanatomical experiments further indicated that LPS did not interfere with the ability of CNO to stimulate c-Fos in AgRP neurons. In summary, our findings combined together support the view that the stimulation of select AgRP-innervated brain sites and target neurons, rather than the inhibition of AgRP neurons themselves, is likely to contribute to the rapid suppression of food intake observed during acute bacterial endotoxemia.
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Affiliation(s)
- Yang Liu
- Division of Hypothalamic Research and Department of Internal Medicine (Y.L., Y.H., T.L., L.G.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390; Department of Orthopedics (Y.L., H.W.), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China 430030; and Department of Pharmacology (H.C.), Center for Hypertension Research, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Carver College of Medicine, Iowa City, Iowa 52242
| | - Ying Huang
- Division of Hypothalamic Research and Department of Internal Medicine (Y.L., Y.H., T.L., L.G.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390; Department of Orthopedics (Y.L., H.W.), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China 430030; and Department of Pharmacology (H.C.), Center for Hypertension Research, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Carver College of Medicine, Iowa City, Iowa 52242
| | - Tiemin Liu
- Division of Hypothalamic Research and Department of Internal Medicine (Y.L., Y.H., T.L., L.G.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390; Department of Orthopedics (Y.L., H.W.), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China 430030; and Department of Pharmacology (H.C.), Center for Hypertension Research, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Carver College of Medicine, Iowa City, Iowa 52242
| | - Hua Wu
- Division of Hypothalamic Research and Department of Internal Medicine (Y.L., Y.H., T.L., L.G.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390; Department of Orthopedics (Y.L., H.W.), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China 430030; and Department of Pharmacology (H.C.), Center for Hypertension Research, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Carver College of Medicine, Iowa City, Iowa 52242
| | - Huxing Cui
- Division of Hypothalamic Research and Department of Internal Medicine (Y.L., Y.H., T.L., L.G.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390; Department of Orthopedics (Y.L., H.W.), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China 430030; and Department of Pharmacology (H.C.), Center for Hypertension Research, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Carver College of Medicine, Iowa City, Iowa 52242
| | - Laurent Gautron
- Division of Hypothalamic Research and Department of Internal Medicine (Y.L., Y.H., T.L., L.G.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390; Department of Orthopedics (Y.L., H.W.), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China 430030; and Department of Pharmacology (H.C.), Center for Hypertension Research, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Carver College of Medicine, Iowa City, Iowa 52242
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4
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Rummel C, Bredehöft J, Damm J, Schweighöfer H, Peek V, Harden LM. Obesity Impacts Fever and Sickness Behavior During Acute Systemic Inflammation. Physiology (Bethesda) 2016; 31:117-30. [DOI: 10.1152/physiol.00049.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Obesity is reaching dramatic proportions in humans and is associated with a higher risk for cardiovascular disease, diabetes, and cognitive alterations, and a higher mortality during infection and inflammation. The focus of the present review is on the influence of obesity on the presentation of fever, sickness behavior, and inflammatory responses during acute systemic inflammation.
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Affiliation(s)
- Christoph Rummel
- Department of Veterinary-Physiology and Biochemistry, Justus-Liebig-University Giessen, Giessen, Germany; and
| | - Janne Bredehöft
- Department of Veterinary-Physiology and Biochemistry, Justus-Liebig-University Giessen, Giessen, Germany; and
| | - Jelena Damm
- Department of Veterinary-Physiology and Biochemistry, Justus-Liebig-University Giessen, Giessen, Germany; and
| | - Hanna Schweighöfer
- Department of Veterinary-Physiology and Biochemistry, Justus-Liebig-University Giessen, Giessen, Germany; and
| | - Verena Peek
- Department of Veterinary-Physiology and Biochemistry, Justus-Liebig-University Giessen, Giessen, Germany; and
| | - Lois M Harden
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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Dysregulation of energy balance by trichothecene mycotoxins: Mechanisms and prospects. Neurotoxicology 2015; 49:15-27. [PMID: 25956358 DOI: 10.1016/j.neuro.2015.04.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 04/14/2015] [Accepted: 04/26/2015] [Indexed: 11/23/2022]
Abstract
Trichothecenes are toxic metabolites produced by fungi that constitute a worldwide hazard for agricultural production and both animal and human health. More than 40 countries have introduced regulations or guidelines for food and feed contamination levels of the most prevalent trichothecene, deoxynivalenol (DON), on the basis of its ability to cause growth suppression. With the development of analytical tools, evaluation of food contamination and exposure revealed that a significant proportion of the human population is chronically exposed to DON doses exceeding the provisional maximum tolerable daily dose. Accordingly, a better understanding of trichothecene impact on health is needed. Upon exposure to low or moderate doses, DON and other trichothecenes induce anorexia, vomiting and reduced weight gain. Several recent studies have addressed the mechanisms by which trichothecenes induce these symptoms and revealed a multifaceted action targeting gut, liver and brain and causing dysregulation in neuroendocrine signaling, immune responses, growth hormone axis, and central neurocircuitries involved in energy homeostasis. Newly identified trichothecene toxicosis biomarkers are just beginning to be exploited and already open up new questions on the potential harmful effects of chronic exposure to DON at apparently asymptomatic very low levels. This review summarizes our current understanding of the effects of DON and other trichothecenes on food intake and weight growth.
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