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Lopez-Rodriguez AB, Murray CL, Kealy J, Towns C, Roche A, Nazmi A, Doran M, Lowry JP, Cunningham C. Hyperthermia elevates brain temperature and improves behavioural signs in animal models of autism spectrum disorder. Mol Autism 2023; 14:43. [PMID: 37968722 PMCID: PMC10652497 DOI: 10.1186/s13229-023-00569-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 09/25/2023] [Indexed: 11/17/2023] Open
Abstract
BACKGROUND Autism spectrum disorders (ASD) are predominantly neurodevelopmental and largely genetically determined. However, there are human data supporting the idea that fever can improve symptoms in some individuals, but those data are limited and there are almost no data to support this from animal models. We aimed to test the hypothesis that elevated body temperature would improve function in two animal models of ASD. METHODS We used a 4 h whole-body hyperthermia (WBH) protocol and, separately, systemic inflammation induced by bacterial endotoxin (LPS) at 250 µg/kg, to dissociate temperature and inflammatory elements of fever in two ASD animal models: C58/J and Shank3B- mice. We used one- or two-way ANOVA and t-tests with normally distributed data and Kruskal-Wallis or Mann-Whitney with nonparametric data. Post hoc comparisons were made with a level of significance set at p < 0.05. For correlation analyses, data were adjusted by a linear regression model. RESULTS Only LPS induced inflammatory signatures in the brain while only WBH produced fever-range hyperthermia. WBH reduced repetitive behaviours and improved social interaction in C58/J mice and significantly reduced compulsive grooming in Shank3B- mice. LPS significantly suppressed most activities over 5-48 h. LIMITATIONS We show behavioural, cellular and molecular changes, but provide no specific mechanistic explanation for the observed behavioural improvements. CONCLUSIONS The data are the first, to our knowledge, to demonstrate that elevated body temperature can improve behavioural signs in 2 distinct ASD models. Given the developmental nature of ASD, evidence that symptoms may be improved by environmental perturbations indicates possibilities for improving function in these individuals. Since experimental hyperthermia in patients would carry significant risks, it is now essential to pursue molecular mechanisms through which hyperthermia might bring about the observed benefits.
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Affiliation(s)
- Ana Belen Lopez-Rodriguez
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Republic of Ireland
| | - Carol L Murray
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Republic of Ireland
| | - John Kealy
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Republic of Ireland
| | - Clodagh Towns
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Republic of Ireland
| | - Andrew Roche
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Republic of Ireland
| | - Arshed Nazmi
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Republic of Ireland
| | - Michelle Doran
- Department of Chemistry, Maynooth University, Maynooth, Co. Kildare, Republic of Ireland
| | - John P Lowry
- Department of Chemistry, Maynooth University, Maynooth, Co. Kildare, Republic of Ireland
| | - Colm Cunningham
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Republic of Ireland.
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2
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Nazabal A, Mendiguren A, Pineda J. Inhibition of rat locus coeruleus neurons by prostaglandin E 2 EP3 receptors: pharmacological characterization ex vivo. Front Pharmacol 2023; 14:1290605. [PMID: 38035000 PMCID: PMC10684765 DOI: 10.3389/fphar.2023.1290605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 10/30/2023] [Indexed: 12/02/2023] Open
Abstract
Prostaglandin E2 (PGE2) is an inflammatory mediator synthesized by the brain constitutive cyclooxygenase enzyme. PGE2 binds to G protein-coupled EP1-4 receptors (EP1 to Gq, EP2,4 to Gs, and EP3 to Gi/o). EP2, EP3 and EP4 receptors are expressed in the locus coeruleus (LC), the main noradrenergic nucleus in the brain. EP3 receptors have been explored in the central nervous system, although its role regulating the locus coeruleus neuron activity has not been pharmacologically defined. Our aim was to characterize the function of EP3 receptors in neurons of the LC. Thus, we studied the effect of EP3 receptor agonists on the firing activity of LC cells in rat brain slices by single-unit extracellular electrophysiological techniques. The EP3 receptor agonist sulprostone (0.15 nM-1.28 µM), PGE2 (0.31 nM-10.2 µM) and the PGE1 analogue misoprostol (0.31 nM-2.56 µM) inhibited the firing rate of LC neurons in a concentration-dependent manner (EC50 = 15 nM, 110 nM, and 51 nM, respectively). The EP3 receptor antagonist L-798,106 (3-10 µM), but not the EP2 (PF-04418948, 3-10 µM) or EP4 (L-161,982, 3-10 µM) receptor antagonists, caused rightward shifts in the concentration-effect curves for the EP3 receptor agonists. Sulprostone-induced effect was attenuated by the Gi/o protein blocker pertussis toxin (pertussis toxin, 500 ng ml-1) and the inhibitors of inwardly rectifying potassium channels (GIRK) BaCl2 (300 µM) and SCH-23390 (15 µM). In conclusion, LC neuron firing activity is regulated by EP3 receptors, presumably by an inhibitory Gi/o protein- and GIRK-mediated mechanism.
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3
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Rolls A. Immunoception: the insular cortex perspective. Cell Mol Immunol 2023; 20:1270-1276. [PMID: 37386172 PMCID: PMC10616063 DOI: 10.1038/s41423-023-01051-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 05/29/2023] [Indexed: 07/01/2023] Open
Abstract
To define the systemic neuroimmune interactions in health and disease, we recently suggested immunoception as a term that refers to the existence of bidirectional functional loops between the brain and the immune system. This concept suggests that the brain constantly monitors changes in immune activity and, in turn, can regulate the immune system to generate a physiologically synchronized response. Therefore, the brain has to represent information regarding the state of the immune system, which can occure in multiple ways. One such representation is an immunengram, a trace that is partially stored by neurons and partially by the local tissue. This review will discuss our current understanding of immunoception and immunengrams, focusing on their manifestation in a specific brain region, the insular cortex (IC).
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Affiliation(s)
- Asya Rolls
- Department of Immunology, Department of Neuroscience, Technion, Israel Institute of Technology, Haifa, Israel.
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4
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Kamm GB, Siemens J. Neuroscience: Detection of systemic inflammation by the brain. Curr Biol 2022; 32:R751-R753. [PMID: 35820388 DOI: 10.1016/j.cub.2022.05.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
When confronted with illness, humans and animals undergo critical changes in their behavior and physiology. New research shows how neuronal circuits detect sickness and coordinate illness-specific responses.
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Affiliation(s)
- Gretel B Kamm
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Jan Siemens
- Department of Pharmacology, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany; Molecular Medicine Partnership Unit (MMPU), European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117 Heidelberg, Germany.
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5
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Litvin DG, Denstaedt SJ, Borkowski LF, Nichols NL, Dick TE, Smith CB, Jacono FJ. Peripheral-to-central immune communication at the area postrema glial-barrier following bleomycin-induced sterile lung injury in adult rats. Brain Behav Immun 2020; 87:610-633. [PMID: 32097765 PMCID: PMC8895345 DOI: 10.1016/j.bbi.2020.02.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 02/02/2020] [Accepted: 02/13/2020] [Indexed: 02/07/2023] Open
Abstract
The pathways for peripheral-to-central immune communication (P → C I-comm) following sterile lung injury (SLI) are unknown. SLI evokes systemic and central inflammation, which alters central respiratory control and viscerosensory transmission in the nucleus tractus solitarii (nTS). These functional changes coincide with increased interleukin-1 beta (IL-1β) in the area postrema, a sensory circumventricular organ that connects P → C I-comm to brainstem circuits that control homeostasis. We hypothesize that IL-1β and its downstream transcriptional target, cyclooxygenase-2 (COX-2), mediate P → C I-comm in the nTS. In a rodent model of SLI induced by intratracheal bleomycin (Bleo), the sigh frequency and duration of post-sigh apnea increased in Bleo- compared to saline- treated rats one week after injury. This SLI-dependent change in respiratory control occurred concurrently with augmented IL-1β and COX-2 immunoreactivity (IR) in the funiculus separans (FS), a barrier between the AP and the brainstem. At this barrier, increases in IL-1β and COX-2 IR were confined to processes that stained for glial fibrillary acidic protein (GFAP) and that projected basolaterally to the nTS. Further, FS radial-glia did not express TNF-α or IL-6 following SLI. To test our hypothesis, we blocked central COX-1/2 activity by intracerebroventricular (ICV) infusion of Indomethacin (Ind). Continuous ICV Ind treatment prevented Bleo-dependent increases in GFAP + and IL-1β + IR, and restored characteristics of sighs that reset the rhythm. These data indicate that changes in sighs following SLI depend partially on activation of a central COX-dependent P → C I-comm via radial-glia of the FS.
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Affiliation(s)
- David G Litvin
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Department of Fundamental Neuroscience, University of Lausanne, 1005 Lausanne, Switzerland
| | - Scott J Denstaedt
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Lauren F Borkowski
- Department of Biomedical Sciences, University of Missouri College of Veterinary Medicine, Columbia, MO 65212, United States
| | - Nicole L Nichols
- Department of Biomedical Sciences, University of Missouri College of Veterinary Medicine, Columbia, MO 65212, United States
| | - Thomas E Dick
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Corey B Smith
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Frank J Jacono
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Division of Pulmonary, Critical Care and Sleep Medicine, Louis Stokes VA Medical Center, Cleveland, OH 44106, United States.
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6
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Mota CMD, Rodrigues-Santos C, Fernández RAR, Carolino ROG, Antunes-Rodrigues J, Anselmo-Franci JA, Branco LGS. Central serotonin attenuates LPS-induced systemic inflammation. Brain Behav Immun 2017; 66:372-381. [PMID: 28723348 DOI: 10.1016/j.bbi.2017.07.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 07/06/2017] [Accepted: 07/15/2017] [Indexed: 12/21/2022] Open
Abstract
Serotonin (5-HT) is a neuromodulator involved in several central-mediated mechanisms, such as endocrine processes, behavior, and sleep. Dysfunction of the serotonergic system is mainly linked to psychiatric disorders, but emerging evidence suggests that immune system activation may also alter brain 5-HT signaling. However, whether central 5-HT modulates systemic inflammation (SI) remains unknown. For this purpose, male Wistar rats (280-350g, 8-9weeks) were submitted to the experimental protocols beginning between 9 and 10AM with the performance of injections. The animals were housed at controlled conditions [temperature (25±1°C), light (06:00-18:00) and humidity (60-65%)]. Thus, we measured 5-HT and its metabolite 5-hydroxyindole-3-acetic acid (5-HIAA) in the anteroventral preoptic region [(AVPO) - the hierarchically most important region for body temperature (Tb) control] during lipopolysaccharide (LPS)-induced SI. We also combined LPS (100μg/kg) treatment with intracerebroventricular (icv) injection of 5-HT (5, 10 and 40μg/μL) and measured Tb ("hallmark" of SI), AVPO prostaglandin E2 [(PGE2) - an essential mediator of fever] and prostaglandin D2 [(PGD2) - a cryogenic mediator], plasma corticosterone [(CORT) - a stress marker with an endogenous anti-inflammatory effect] and interleukin-6 [(IL-6) - an immune mediator] levels. Detection limits of PGE2, PGD2, CORT and IL-6 assays were 39.1-2500pg/mL, 19.5-2500pg/mL, 0.12-2000μg/dL, and 0.125-8ng/mL, respectively. We also assessed tail skin temperature [used to calculate heat loss index (HLI)] to assess a key thermoeffector mechanism. As expected we observed LPS-induced increases in Tb, AVPO PGE2 (whereas PGD2 remained unchanged), plasma CORT and IL-6 levels, as well as a decrease in HLI. These changes were accompanied by reduced levels of AVPO 5-HT and 5-HIAA. Furthermore, we also observed a negative correlation between 5-HT and plasma CORT levels. Moreover, icv 5-HT (5, 10 and 40μg/μL) microinjection caused a U-shaped dose-response curve in LPS fever, in which the intermediate dose reduced the febrile response. Icv 5-HT (10μg/μL) microinjection prevented the LPS-induced increases in AVPO PGE2 (whereas not altering PGD2), plasma CORT and IL-6 levels, as well as preventing reduced HLI. Our data are consistent with the notion that AVPO 5-HT synthesis is down-regulated during SI, favoring AVPO PGE2 synthesis and consequently potentiating the immune response. These results reveal a novel effect of central 5-HT as an anti-inflammatory neuromodulator that may take place during psychiatric disorder treatment with 5-HT reuptake inhibitors as well as suggesting that 5-HT modulation per se is a potential therapeutic approach for inflammatory diseases.
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Affiliation(s)
- Clarissa M D Mota
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Caroline Rodrigues-Santos
- Department of Morphology, Physiology and Basic Pathology, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Rodrigo A R Fernández
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Ruither O G Carolino
- Department of Morphology, Physiology and Basic Pathology, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - José Antunes-Rodrigues
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Janete A Anselmo-Franci
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil; Department of Morphology, Physiology and Basic Pathology, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Luiz G S Branco
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil; Department of Morphology, Physiology and Basic Pathology, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
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7
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Puberty as a vulnerable period to the effects of immune challenges: Focus on sex differences. Behav Brain Res 2016; 320:374-382. [PMID: 27836584 DOI: 10.1016/j.bbr.2016.11.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 11/02/2016] [Accepted: 11/04/2016] [Indexed: 12/16/2022]
Abstract
Puberty is a critical period of development during which sexual maturity is attained. It is also a critical period for brain reorganization and it is vulnerable to exposure to certain environmental factors. Exposure to stress during this period can cause enduring neural and behavioral alterations. More specifically, exposure to an immune challenge during this period can alter reproductive as well as a number of non-reproductive behaviors and can permanently alter the brain's response to gonadal hormones. The present review examines the enduring effect of exposure to LPS and poly(I:C) during the pubertal period. Age and sex differences in acute response to LPS are discussed as possible mechanisms of vulnerability to adverse effects. Moreover, this review suggests new research directions to improve our understanding of the vulnerability of the pubertal period to immunological stressors.
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8
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Sickness: From the focus on cytokines, prostaglandins, and complement factors to the perspectives of neurons. Neurosci Biobehav Rev 2015; 57:30-45. [PMID: 26363665 DOI: 10.1016/j.neubiorev.2015.07.015] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 07/06/2015] [Accepted: 07/31/2015] [Indexed: 12/29/2022]
Abstract
Systemic inflammation leads to a variety of physiological (e.g. fever) and behavioral (e.g. anorexia, immobility, social withdrawal, depressed mood, disturbed sleep) responses that are collectively known as sickness. While these phenomena have been studied for the past few decades, the neurobiological mechanisms by which sickness occurs remain unclear. In this review, we first revisit how the body senses and responds to infections and injuries by eliciting systemic inflammation. Next, we focus on how peripheral inflammatory molecules such as cytokines, prostaglandins, and activated complement factors communicate with the brain to trigger neuroinflammation and sickness. Since depression also involves inflammation, we further elaborate on the interrelationship between sickness and depression. Finally, we discuss how immune activation can modulate neurons in the brain, and suggest future perspectives to help unravel how changes in neuronal functions relate to sickness responses.
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9
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Girard-Joyal O, Faragher A, Bradley K, Kane L, Hrycyk L, Ismail N. Age and sex differences in c-Fos expression and serum corticosterone concentration following LPS treatment. Neuroscience 2015; 305:293-301. [PMID: 26117716 DOI: 10.1016/j.neuroscience.2015.06.035] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 06/18/2015] [Accepted: 06/20/2015] [Indexed: 10/23/2022]
Abstract
Exposure to an immune challenge during peripuberty/adolescence, but not in adulthood, can cause enduring alterations in reproductive and non-reproductive behaviors. This suggests that the peripubertal/adolescent brain might respond differently to a stressor, like an immune challenge, than the adult brain. The goal of this study was to examine whether there are age and sex differences in the acute response to an immune challenge. To examine this research question, we investigated c-Fos expression in various brain regions. Corticosterone (CORT) concentration in the serum was quantified to examine hypothalamic-pituitary-adrenal axis (HPA-axis) responsiveness. Results showed that lipopolysaccharide (LPS; a bacterial endotoxin) treatment, induced a significant increase in the number of c-Fos immunoreactive cells in adult male and female mice compared to their saline controls. However, in peripubertal/adolescent mice, LPS treatment failed to increase the number of c-Fos immunoreactive cells in both male and female mice compared to their saline controls. LPS treatment also significantly increased serum CORT concentration in all mice regardless of sex and age. However, adult female mice treated with LPS showed significantly greater serum CORT concentration compared to adult and peripubertal/adolescent males and peripubertal/adolescent females treated with LPS. These findings support our hypothesis and suggest that there are important age and sex differences in acute immune response, which may allude to mechanisms for the enduring behavioral alterations, observed previously in mice exposed to an immune challenge during puberty but not in adulthood.
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Affiliation(s)
- O Girard-Joyal
- School of Psychology, University of Ottawa, Ottawa, ON, Canada
| | - A Faragher
- School of Psychology, University of Ottawa, Ottawa, ON, Canada
| | - K Bradley
- School of Psychology, University of Ottawa, Ottawa, ON, Canada
| | - L Kane
- School of Psychology, University of Ottawa, Ottawa, ON, Canada
| | - L Hrycyk
- School of Psychology, University of Ottawa, Ottawa, ON, Canada
| | - N Ismail
- School of Psychology, University of Ottawa, Ottawa, ON, Canada.
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10
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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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11
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Rouquet T, Clément P, Gaigé S, Tardivel C, Roux J, Dallaporta M, Bariohay B, Troadec JD, Lebrun B. Acute oral metformin enhances satiation and activates brainstem nesfatinergic neurons. Obesity (Silver Spring) 2014; 22:2552-62. [PMID: 25236366 DOI: 10.1002/oby.20902] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 08/18/2014] [Indexed: 11/12/2022]
Abstract
OBJECTIVE The study was designed to determine metformin effects on meal pattern, gastric emptying, energy expenditure, and to identify metformin-sensitive neurons and their phenotype. METHODS This study was performed on C57BL/6J and obese/diabetic (db/db) mice. Metformin (300 mg/kg) was administered by oral gavage. Food intake, meal pattern, oxygen consumption (VO2 ), and carbon dioxide production (VCO2 ) were obtained using an Oxylet Physiocage System. Gastric emptying assay and real-time RT-PCR from dorsal vagal complex extracts were also performed. C-Fos expression was used as a marker of neuronal activation. Phenotypic characterization of activated neurons was performed using either proopiomelanocortin (POMC)-Tau-Topaz GFP transgenic mice or NUCB2/nesfatin-1 and tyrosine hydroxylase (TH) labeling. RESULTS Acute per os metformin treatment slowed down gastric emptying, reduced meal size, but not meal number in a leptin-independent manner, and transiently decreased energy expenditure in a leptin-dependent manner. Metformin specifically activated central circuitry within the brainstem, independently of vagal afferents. Finally, while POMC neurons seemed sparsely activated, we report that a high proportion of the c-Fos positive cells were nesfatinergic neurons, some of which coexpressing TH. CONCLUSIONS Altogether, these results show that metformin modifies satiation by activating brainstem circuitry and suggest that NUCB2/nesfatin-1 could be involved in this metformin effect.
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Affiliation(s)
- Thaïs Rouquet
- EA 4674, Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-Moteur et Neurovégétatif, FST St Jérôme, Aix-Marseille Université, Marseille, France; Biomeostasis CRO, FST St Jérôme, Marseille, France
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12
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Gaigé S, Djelloul M, Tardivel C, Airault C, Félix B, Jean A, Lebrun B, Troadec JD, Dallaporta M. Modification of energy balance induced by the food contaminant T-2 toxin: a multimodal gut-to-brain connection. Brain Behav Immun 2014; 37:54-72. [PMID: 24355099 DOI: 10.1016/j.bbi.2013.12.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 11/27/2013] [Accepted: 12/10/2013] [Indexed: 12/12/2022] Open
Abstract
T-2 toxin is one of the most toxic Fusarium-derived trichothecenes found on cereals and constitutes a widespread contaminant of agricultural commodities as well as commercial foods. Low doses toxicity is characterized by reduced weight gain. To date, the mechanisms by which this mycotoxin profoundly modifies feeding behavior remain poorly understood and more broadly the effects of T-2 toxin on the central nervous system (CNS) have received limited attention. Through an extensive characterization of sickness-like behavior induced by T-2 toxin, we showed that its per os (p.o.) administration affects not only feeding behavior but also energy expenditure, glycaemia, body temperature and locomotor activity. Using c-Fos expression mapping, we identified the neuronal structures activated in response to T-2 toxin and observed that the pattern of neuronal populations activated by this toxin resembled that induced by inflammatory signals. Interestingly, part of neuronal pathways activated by the toxin were NUCB-2/nesfatin-1 expressing neurons. Unexpectedly, while T-2 toxin induced a strong peripheral inflammation, the brain exhibited limited inflammatory response at a time point when anorexia was ongoing. Unilateral vagotomy partly reduced T-2 toxin-induced brainstem neuronal activation. On the other hand, intracerebroventricular (icv) T-2 toxin injection resulted in a rapid (<1h) reduction in food intake. Thus, we hypothesized that T-2 toxin could signal to the brain through neuronal and/or humoral pathways. The present work provides the first demonstration that T-2 toxin modifies feeding behavior by interfering with central neuronal networks devoted to central energy balance. Our results, with a particular attention to peripheral inflammation, strongly suggest that inflammatory mediators partake in the T-2 toxin-induced anorexia and other symptoms. In view of the broad human and breeding animal exposure to T-2 toxin, this new mechanism may lead to reconsider the impact of the consumption of this toxin on human health.
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Affiliation(s)
- Stéphanie Gaigé
- EA 4674, Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-Moteur et Neurovégétatif, FST St Jérôme. Aix-Marseille Université, Avenue Escadrille Normandie-Niemen, 13013 Marseille, France
| | - Mehdi Djelloul
- EA 4674, Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-Moteur et Neurovégétatif, FST St Jérôme. Aix-Marseille Université, Avenue Escadrille Normandie-Niemen, 13013 Marseille, France
| | - Catherine Tardivel
- EA 4674, Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-Moteur et Neurovégétatif, FST St Jérôme. Aix-Marseille Université, Avenue Escadrille Normandie-Niemen, 13013 Marseille, France; INRA U1189, Département AlimH, 63122 St Genés Champenelle, France
| | - Coraline Airault
- EA 4674, Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-Moteur et Neurovégétatif, FST St Jérôme. Aix-Marseille Université, Avenue Escadrille Normandie-Niemen, 13013 Marseille, France
| | - Bernadette Félix
- EA 4674, Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-Moteur et Neurovégétatif, FST St Jérôme. Aix-Marseille Université, Avenue Escadrille Normandie-Niemen, 13013 Marseille, France; INRA U1189, Département AlimH, 63122 St Genés Champenelle, France
| | - André Jean
- EA 4674, Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-Moteur et Neurovégétatif, FST St Jérôme. Aix-Marseille Université, Avenue Escadrille Normandie-Niemen, 13013 Marseille, France
| | - Bruno Lebrun
- EA 4674, Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-Moteur et Neurovégétatif, FST St Jérôme. Aix-Marseille Université, Avenue Escadrille Normandie-Niemen, 13013 Marseille, France
| | - Jean-Denis Troadec
- EA 4674, Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-Moteur et Neurovégétatif, FST St Jérôme. Aix-Marseille Université, Avenue Escadrille Normandie-Niemen, 13013 Marseille, France.
| | - Michel Dallaporta
- EA 4674, Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-Moteur et Neurovégétatif, FST St Jérôme. Aix-Marseille Université, Avenue Escadrille Normandie-Niemen, 13013 Marseille, France.
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13
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Ma Y, Matsuwaki T, Yamanouchi K, Nishihara M. Differential roles of cyclooxygenase-2-related signaling in regulating hypothalamic neuronal activity under various acute stresses. J Vet Med Sci 2013; 76:219-27. [PMID: 24141321 PMCID: PMC3982819 DOI: 10.1292/jvms.13-0234] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have previously suggested that activation of the hypothalamic-pituitary-adrenal (HPA) axis is dependent on cyclooxygenase (COX)-2-related signaling under infectious and restraint stresses, but less dependent on it under hypoglycemic stress. In the present study, we evaluated the neuronal activity in the brain to elucidate the possible mechanisms underlying a stress-specific relevance between COX-2-related signaling and activation of the HPA axis under infectious (lipopolysaccharide, LPS), hypoglycemic (2-deoxy-D-glucose, 2DG) and restraint (1 hr) stress conditions. The number of c-Fos-immunoreactive (IR) cells in several brain regions including the paraventricular nucleus (PVN) and supraoptic nucleus (SON) was increased at 120 min after application of all stress stimuli. The number of c-Fos-IR cells at 30 min was increased only by 2DG in the SON, but not in the PVN. In the PVN, a selective COX-2 inhibitor (NS-398) did not affect the number of c-Fos-IR cells at any time points. On the other hand, in the SON, NS-398 increased c-Fos-IR cells at 30 min after LPS and restraint stresses, but not after 2DG injection. These results suggest that, among the brain regions responding to acute stresses, the PVN and SON are commonly activated under three acute stresses. In addition, it is also suggested that COX-2-related signaling decreases neuronal activity in the SON under infectious and restraint, but not hypoglycemic, stresses, which may be involved in the suppression of the HPA axis.
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Affiliation(s)
- Yanbo Ma
- Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
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14
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Vasilache AM, Kugelberg U, Blomqvist A, Nilsberth C. Minor changes in gene expression in the mouse preoptic hypothalamic region by inflammation-induced prostaglandin E2. J Neuroendocrinol 2013; 25:635-43. [PMID: 23631667 DOI: 10.1111/jne.12044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/14/2013] [Accepted: 04/26/2013] [Indexed: 11/30/2022]
Abstract
We investigated to what extent inflammation-induced prostaglandin E2 (PGE2 ) regulates gene expression in the central nervous system. Wild-type mice and mice with deletion of the gene encoding microsomal prostaglandin E synthase-1 (mPGES-1), which cannot produce inflammation-induced PGE2 , were subjected to peripheral injection of bacterial wall lipopolysaccharide (LPS) and killed after 5 h. The median and medial preoptic nuclei, which are rich in prostaglandin E receptors, were isolated by laser capture microdissection (LCM), and subjected to whole genome microarray analysis. Although the immune stimulus induced robust transcriptional changes in the brain, as seen by a quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) on selected genes, only small PGE2 -dependent gene expression changes were observed in the gene array analysis and, for only two genes, a pronounced differential expression between LPS-treated wild-type and mPGES-1 knockout mice could be verified by qRT-PCR. These were Hspa1a and Hspa1b, encoding heat shock proteins, which showed a two- to three-fold higher expression in wild-type mice than in knockout mice after immune challenge. However, the induced expression of these genes was found to be secondary to increased body temperature because they were induced also by cage exchange stress, which did not elicit PGE2 synthesis, and thus were not induced per se by PGE2 -elicited transcriptional events. Our findings suggest that inflammation-induced PGE2 has little effect on gene expression in the preoptic region, and that centrally elicited disease symptoms, although PGE2 -dependent, occur as a result of regulation of neuronal excitability that is a consequence of intracellular, transcriptional-independent signalling cascades. Our findings also imply that the profound changes in gene expression in the brain that are elicited by peripheral inflammation occur independently of PGE2 via a yet unidentified mechanism.
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Affiliation(s)
- A M Vasilache
- Division of Cell Biology, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, S-581 85 Linköping, Sweden
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15
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Inhibition of nitric oxide synthase accentuates endotoxin-induced sickness behavior in mice. Pharmacol Biochem Behav 2013; 103:535-40. [DOI: 10.1016/j.pbb.2012.09.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 09/18/2012] [Accepted: 09/29/2012] [Indexed: 12/27/2022]
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16
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Gaigé S, Bonnet MS, Tardivel C, Pinton P, Trouslard J, Jean A, Guzylack L, Troadec JD, Dallaporta M. c-Fos immunoreactivity in the pig brain following deoxynivalenol intoxication: focus on NUCB2/nesfatin-1 expressing neurons. Neurotoxicology 2012; 34:135-49. [PMID: 23164930 DOI: 10.1016/j.neuro.2012.10.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 10/24/2012] [Accepted: 10/26/2012] [Indexed: 10/27/2022]
Abstract
Deoxynivalenol (DON), produced by the cereal-contaminating Fusarium fungi, is a major trichothecene responsible for mycotoxicoses in farm animals, including swine. The main effect of DON-intoxication is food intake reduction and the consequent body weight loss. The present study aimed to identify brain structures activated during DON intoxication in pigs. To this goal, we used c-Fos staining which constitutes a useful approach to identify activated neurons. We showed that per os administration of Fusarium graminearum extracts (containing the equivalent of 1mg DON per kg of body weight) induced an increase in c-Fos immunoreactivity in several central structures, including the ventrolateral medulla (VLM), dorsal vagal complex (DVC), paraventricular nucleus of the hypothalamus (PVN), arcuate nucleus (Arc), supraoptic nucleus (SON) and amygdala (CeA). Moreover, we coupled c-Fos staining with phenotypic markers detection in order to specify the neuronal populations activated during DON intoxication. This phenotypic characterization revealed the activation of catecholaminergic but not of serotoninergic neurons in response to the toxin. In this context, we also paid a particular attention to NUCB2/nesfatin-1 positive cells, since nesfatin-1 is known to exert a satiety effect. We report here, for the first time in the pig brain, the presence of NUCB2/nesfatin-1 neurons in the VLM, DVC, PVN, Arc and SON, and their activation during DON intoxication. Taken together, these data show that DON stimulates the main structures involved in food intake in pigs and suggest that catecholaminergic and NUCB2/nesfatin-1 neurons could contribute in the anorexigenic effects of the mycotoxin.
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Affiliation(s)
- Stéphanie Gaigé
- EA 4674, Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-Moteur et Neurovégétatif, FST St. Jérôme, Aix-Marseille Université, 13013 Marseille, France
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17
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Soncini R, de Souza DF, Neves AP, Braga DS, Andrade CA, Giusti-Paiva A. Dipyrone attenuates acute sickness response to lipopolysaccharide in mice. Neurosci Lett 2012; 516:114-8. [DOI: 10.1016/j.neulet.2012.03.070] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 03/22/2012] [Accepted: 03/25/2012] [Indexed: 12/21/2022]
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18
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Abstract
Cachexia is a metabolic syndrome that manifests with excessive weight loss and disproportionate muscle wasting. It is related to many different chronic diseases, such as cancer, infections, liver disease, inflammatory bowel disease, cardiac disease, chronic obstructive pulmonary disease, chronic renal failure and rheumatoid arthritis. Cachexia is linked with poor outcome for the patients. In this article, we explore the role of the hypothalamus, liver, muscle tissue and adipose tissue in the pathogenesis of this syndrome, particularly concentrating on the role of cytokines, hormones and cell energy-controlling pathways (such as AMPK, PI3K/Akt and mTOR). We also look at possible future directions for therapeutic strategies.
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Affiliation(s)
| | - Sarah Briggs
- a Paediatric Liver, GI and Nutrition Centre, King's College Hospital, Denmark Hill, London, SE5 9RS, UK
| | - Anil Dhawan
- a Paediatric Liver, GI and Nutrition Centre, King's College Hospital, Denmark Hill, London, SE5 9RS, UK
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19
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Haba R, Shintani N, Onaka Y, Wang H, Takenaga R, Hayata A, Baba A, Hashimoto H. Lipopolysaccharide affects exploratory behaviors toward novel objects by impairing cognition and/or motivation in mice: Possible role of activation of the central amygdala. Behav Brain Res 2011; 228:423-31. [PMID: 22209851 DOI: 10.1016/j.bbr.2011.12.027] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 12/10/2011] [Accepted: 12/16/2011] [Indexed: 12/14/2022]
Abstract
Lipopolysaccharide (LPS) produces a series of systemic and psychiatric changes called sickness behavior. In the present study, we characterized the LPS-induced decrease in novel object exploratory behaviors in BALB/c mice. As already reported, LPS (0.3-5 μg/mouse) induced dose- and time-dependent decreases in locomotor activity, food intake, social interaction, and exploration for novel objects, and an increase in immobility in the forced-swim test. Although the decrease in locomotor activity was ameliorated by 10h postinjection, novel object exploratory behaviors remained decreased at 24h and were observed even with the lowest dose of LPS. In an object exploration test, LPS shortened object exploration time but did not affect moving time or the frequency of object exploration. Although pre-exposure to the same object markedly decreased the duration of exploration and LPS did not change this reduction, LPS significantly impaired the exploration of a novel object that replaced the familiar one. LPS did not affect anxiety-like behaviors in open-field and elevated plus-maze tests. An LPS-induced increase in the number of c-Fos-immunoreactive cells was observed in several brain regions within 6h of LPS administration, but the number of cells quickly returned to control levels, except in the central amygdala where the increase continued for 24h. These results suggest that LPS most prominently affects object exploratory behaviors by impairing cognition and/or motivation including continuous attention and curiosity toward objects, and that this may be associated with activation of brain nuclei such as the central amygdala.
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Affiliation(s)
- Ryota Haba
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, Japan.
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20
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Inflammation-induced lethargy is mediated by suppression of orexin neuron activity. J Neurosci 2011; 31:11376-86. [PMID: 21813697 DOI: 10.1523/jneurosci.2311-11.2011] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In response to illness, animals subvert normal homeostasis and divert their energy utilization to fight infection. An important and unexplored feature of this response is the suppression of physical activity and foraging behavior in the setting of negative energy balance. Inflammatory signaling in the hypothalamus mediates the febrile and anorectic responses to disease, but the mechanism by which locomotor activity (LMA) is suppressed has not been described. Lateral hypothalamic orexin (Ox) neurons link energy status with LMA, and deficiencies in Ox signaling lead to hypoactivity and hypophagia. In the present work, we examine the effect of endotoxin-induced inflammation on Ox neuron biology and LMA in rats. Our results demonstrate a vital role for diminished Ox signaling in mediating inflammation-induced lethargy. This work defines a specific population of inflammation-sensitive, arousal-associated Ox neurons and identifies a proximal neural target for inflammatory signaling to Ox neurons, while eliminating several others.
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21
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Girardet C, Bonnet MS, Jdir R, Sadoud M, Thirion S, Tardivel C, Roux J, Lebrun B, Mounien L, Trouslard J, Jean A, Dallaporta M, Troadec JD. Central inflammation and sickness-like behavior induced by the food contaminant deoxynivalenol: a PGE2-independent mechanism. Toxicol Sci 2011; 124:179-91. [PMID: 21873375 DOI: 10.1093/toxsci/kfr219] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Deoxynivalenol (DON), one of the most abundant trichothecenes found on cereals, has been implicated in mycotoxicoses in both humans and farm animals. Low-dose toxicity is characterized by reduced weight gain, diminished nutritional efficiency, and immunologic effects. The levels and patterns of human food commodity contamination justify that DON consumption constitutes a public health issue. DON stability during processing and cooking explains its large presence in human food. We characterized here DON intoxication by showing that the toxin concomitantly affects feeding behavior, body temperature, and locomotor activity after both per os and central administration. Using c-Fos expression mapping, we identified the neuronal structures activated in response to DON and observed that the pattern of neuronal populations activated by the toxin resembled those induced by inflammatory signals. By real-time PCR, we report the first evidences for a DON-induced central inflammation, attested by the strong upregulation of interleukin-1β, interleukin-6, tumor necrosis factor-α, cyclooxygenase-2, and microsomal prostaglandin synthase-1 (mPGES-1) messenger RNA. However, silencing prostaglandins E2 signaling pathways using mPGES-1 knockout mice, which are resistant to cytokine-induced sickness behavior, did not modify the responses to the toxin. These results reveal that, despite strong similarities, behavioral changes observed after DON intoxication differ from classical sickness behavior evoked by inflammatory cytokines.
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Affiliation(s)
- Clémence Girardet
- Département de Physiologie Neurovégétative, Centre de Recherche en Neurobiologie-Neurophysiologie de Marseille, Université Paul Cézanne, INRA USC 2027, CNRS UMR 6231, 13397 Marseille, France
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22
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Neuronal nitric oxide contributes to neuroplasticity-associated protein expression through cGMP, protein kinase G, and extracellular signal-regulated kinase. J Neurosci 2011; 31:6947-55. [PMID: 21562256 DOI: 10.1523/jneurosci.0374-11.2011] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Nitric oxide (NO) synthesized by neuronal NO synthase (nNOS) has long been implicated in brain plasticity. However, it is unclear how this short-lived mediator contributes to the long-term molecular changes underlying neuroplasticity, which typically require activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) signaling pathway and gene expression. To address this issue, we used a neuroplasticity model based on treatment of neuronal cultures with bicuculline and a model of experience-dependent plasticity in the barrel cortex. In neuronal cultures, NOS inhibition attenuated the bicuculline-induced activation of ERK and the expression of c-Fos, Egr-1, Arc, and brain-derived neurotrophic factor (BDNF), proteins essential for neuroplasticity. Furthermore, inhibition of the NO target soluble guanylyl cyclase or of the cGMP effector kinase protein kinase G (PKG) reduced both ERK activation and plasticity-related protein expression. NOS inhibition did not affect phosphorylation of cAMP response element-binding protein (CREB), a well-established ERK nuclear target, but it attenuated the nuclear accumulation of the CREB coactivator TORC1 and suppressed the activation of Elk-1, another transcription factor target of ERK. Consistent with these in vitro observations, induction of c-Fos, Egr-1, and BDNF was attenuated in the D1 cortical barrel of nNOS(-/-) mice subjected to single whisker experience. These results establish nNOS-derived NO as a key factor in the expression of proteins involved in neuroplasticity, an effect mediated through cGMP, PKG, and ERK signaling. These actions of NO do not depend on CREB phosphorylation but may involve TORC1 and Elk-1. Our data unveil a previously unrecognized link between neuronal NO and the molecular machinery responsible for the sustained synaptic changes underlying neuroplasticity.
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23
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Kopf BS, Langhans W, Geary N, Hrupka B, Asarian L. Evidence that PGE2 in the dorsal and median raphe nuclei is involved in LPS-induced anorexia in rats. Pharmacol Biochem Behav 2011; 99:437-43. [PMID: 21527272 DOI: 10.1016/j.pbb.2011.04.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 04/08/2011] [Accepted: 04/13/2011] [Indexed: 10/18/2022]
Abstract
Anorexia is an element of the acute-phase immune response. Its mechanisms remain poorly understood. Activation of inducible cyclooxygenase-2 (COX-2) in blood-brain-barrier endothelial cells and subsequent release of prostaglandins (e.g., prostaglandin E2, PGE2) may be involved. Therefore, we sought to relate the effects of prostaglandins on the anorexia following gram-negative bacterial lipopolysaccharide treatment (LPS) to neural activity in the dorsal and median raphe nuclei (DRN and MnR) in rats. COX-2 antagonist (NS-398, 10mg/kg; IP) administration prior to LPS (100μg/kg; IP) prevented anorexia and reduced c-Fos expression the DRN, MnR, nucleus tractus solitarii and several related forebrain areas. These data indicate that COX-2-mediated prostaglandin synthesis is necessary for LPS anorexia and much of the initial LPS-induced neural activation. Injection of NS-398 into the DRN and MnR (1ng/site) attenuated LPS-induced anorexia to nearly the same extent as IP NS-398, suggesting that prostaglandin signaling in these areas is necessary for LPS anorexia. Because the DRN and MnR are sources of major serotonergic projections to the forebrain, these data suggest that serotonergic neurons originating in the midbrain raphe play an important role in acute-phase response anorexia.
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Affiliation(s)
- Brigitte S Kopf
- Physiology and Behaviour Laboratory, Institute of Food, Nutrition and Health, ETH-Zürich, Switzerland
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24
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Abstract
Stress is a state of physiological or psychological strain caused by adverse stimuli; responses to stress include activation of the sympathetic nervous system, glucocorticoid secretion and emotional behaviors. Prostaglandin E(2) (PGE(2)), acting through its four receptor subtypes (EP1, EP2, EP3 and EP4), is involved in these stress responses. Studies of EP-selective drugs and mice lacking specific EPs have identified the neuronal pathways regulated by PGE(2). In animals with febrile illnesses, PGE(2) acts on neurons expressing EP3 in the preoptic hypothalamus. In illness-induced activation of the hypothalamic-pituitary-adrenal axis, EP1 and EP3 regulate distinct neuronal pathways that converge at the paraventricular hypothalamus. During psychological stress, EP1 suppresses impulsive behaviors via the midbrain dopaminergic systems. PGE(2) promotes illness-induced memory impairment, yet also supports hippocampus-dependent memory formation and synaptic plasticity via EP2 in physiological conditions. In response to illness, PGE(2) is synthesized by enzymes induced in various cell types inside and outside the brain, whereas constitutively expressed enzymes in neurons and/or microglia synthesize PGE(2) in response to psychological stress. Dependent on the type of stress stimuli, PGE(2) released from different cell types activates distinct EP receptors, which mobilize multiple neuronal pathways, resulting in stress responses.
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Affiliation(s)
- Tomoyuki Furuyashiki
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Yoshida-konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
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25
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Prostaglandins mediate depressive-like behaviour induced by endotoxin in mice. Behav Brain Res 2010; 215:146-51. [PMID: 20654654 DOI: 10.1016/j.bbr.2010.07.015] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 07/15/2010] [Accepted: 07/15/2010] [Indexed: 11/22/2022]
Abstract
Sickness behaviour appears to be the expression of a central motivational state that reorganises the organism's priorities to cope with infectious pathogens. To evaluate the possible participation of prostaglandins in lipopolysaccharide-induced sickness behaviours, mice were submitted to the tail suspension test (TST), forced swim test (FST), open field test and dark-light box test. Lipopolysaccharide (LPS, 100microg/kg; i.p.) administration increased the time spent immobile in the TST, increased the time spent floating in the FST, and depressed locomotor activity in the open field. Indeed, treatment with LPS decreased the total number of transitions made between the dark and light compartments of the apparatus. Pretreatment with indomethacin (10mg/kg; i.p.) or nimesulide (5mg/kg) blocked behavioural changes induced by LPS in the FTS, TST, open field and light-dark box test. This effect was similar to pretreatment with dexamethasone (1mg/kg), which is a steroidal drug that inhibits immune and inflammatory responses, including cytokine production. These findings confirm previous observations that have reported LPS-induced sickness behaviours. In addition, they provide evidence that the synthesis of prostaglandins is necessary for changes in depressive-like and exploratory behaviours in mice, which is supported by the fact that COX inhibitors also attenuate LPS-induced behavioural changes.
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26
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Asarian L, Langhans W. A new look on brain mechanisms of acute illness anorexia. Physiol Behav 2010; 100:464-71. [PMID: 20394763 DOI: 10.1016/j.physbeh.2010.04.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 03/25/2010] [Accepted: 04/06/2010] [Indexed: 11/17/2022]
Abstract
Bacterial lipopolysaccharide (LPS) and other microbial substances trigger the organism's acute phase response and cause acute illness anorexia. Pro-inflammatory cytokines are major endogenous mediators of acute illness anorexia, but how LPS or cytokines stimulate the brain to inhibit eating is not fully resolved. One emerging mechanism involves the activation of the enzyme cyclooxygenase-2 (COX-2) in blood-brain barrier endothelial cells and the subsequent release of prostaglandin E2 (PGE2). Serotonin neurons in the midbrain raphe are targets of PGE2, and serotonergic projections from the midbrain raphe to the hypothalamus appear to be crucial for LPS anorexia. That is, raphe projections activate (1) the corticotrophin-releasing hormone neurons in the paraventricular nucleus which then elicit the stress response and (2) the pro-opiomelanocortin neurons in the arcuate nucleus which then release alphaMSH and elicit anorexia. Here we review available data to support a role for this brain mechanism in acute illness anorexia by center staging PGE2 signaling pathways that converge on central neural circuits that control normal eating. In addition, we review interactions between gonadal hormones and immune function that lead to sex differences in acute illness anorexia. The paper represents an invited review by a symposium, award winner or keynote speaker at the Society for the Study of Ingestive Behavior [SSIB] Annual Meeting in Portland, July 2009.
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Affiliation(s)
- Lori Asarian
- Institute of Food, Nutrition and Health, ETH Zurich, 8603, Schwerzenbach, Switzerland
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27
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Grossberg AJ, Scarlett JM, Marks DL. Hypothalamic mechanisms in cachexia. Physiol Behav 2010; 100:478-89. [PMID: 20346963 DOI: 10.1016/j.physbeh.2010.03.011] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 03/10/2010] [Accepted: 03/12/2010] [Indexed: 12/12/2022]
Abstract
The role of nutrition and balanced metabolism in normal growth, development, and health maintenance is well known. Patients affected with either acute or chronic diseases often show disorders of nutrient balance. In some cases, a devastating state of malnutrition known as cachexia arises, brought about by a synergistic combination of a dramatic decrease in appetite and an increase in metabolism of fat and lean body mass. Other common features that are not required for the diagnosis include decreases in voluntary movement, insulin resistance, and anhedonia. This combination is found in a number of disorders including cancer, cystic fibrosis, AIDS, rheumatoid arthritis, renal failure, and Alzheimer's disease. The severity of cachexia in these illnesses is often the primary determining factor in both quality of life, and in eventual mortality. Indeed, body mass retention in AIDS patients has a stronger association with survival than any other current measure of the disease. This has led to intense investigation of cachexia and the proposal of numerous hypotheses regarding its etiology. Most authors suggest that cytokines released during inflammation and malignancy act on the central nervous system to alter the release and function of a number of neurotransmitters, thereby altering both appetite and metabolic rate. This review will discuss the salient features of cachexia in human diseases, and review the mechanisms whereby inflammation alters the function of key brain regions to produce stereotypical illness behavior. The paper represents an invited review by a symposium, award winner or keynote speaker at the Society for the Study of Ingestive Behavior [SSIB] Annual Meeting in Portland, July 2009.
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Affiliation(s)
- Aaron J Grossberg
- Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239, USA
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28
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Serotonin 2C receptor signaling in a diffuse neuronal network is necessary for LPS anorexia. Brain Res 2010; 1306:77-84. [DOI: 10.1016/j.brainres.2009.09.079] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 09/16/2009] [Accepted: 09/19/2009] [Indexed: 11/19/2022]
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29
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Hollis JH, Lemus M, Evetts MJ, Oldfield BJ. Central interleukin-10 attenuates lipopolysaccharide-induced changes in food intake, energy expenditure and hypothalamic Fos expression. Neuropharmacology 2009; 58:730-8. [PMID: 20045008 DOI: 10.1016/j.neuropharm.2009.12.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 12/13/2009] [Accepted: 12/18/2009] [Indexed: 10/20/2022]
Abstract
Lipopolysaccharide (LPS) is often used to mimic acute infection and induces hypophagia, the selective partitioning of fat for energy, and fever. Interleukin-10 (IL-10) is an anti-inflammatory cytokine expressed in the brain which attenuates LPS-induced hypophagia; however the potential sites of interaction within the brain have not been investigated. Hypothalamic orexin (ORX) and melanin-concentrating hormone (MCH) regulate energy expenditure and food intake although the regulation of these neuropeptides through the interactions between central IL-10 and the inflammatory consequences of peripheral LPS have not been investigated. The present study in the rat investigated during the dark phase of the light-dark cycle the ability of central IL-10 (250 ng, i.c.v.) to attenuate the changes in food intake, energy substrate partitioning, and central Fos expression within the hypothalamus to peripheral LPS (100 microg/kg, i.p.); Fos expression changes specifically within ORX and MCH neurons were also investigated. Central IL-10 attenuated the peripheral LPS-induced hypophagia, reduction in motor activity, fever and reduction in respiratory exchange ratio. Central IL-10 also attenuated peripheral LPS-induced increases in Fos expression within ORX neurons and decreases in Fos expression within unidentified cells of the caudal arcuate nucleus. In contrast, both IL-10 and LPS injection independently decreased Fos expression within MCH neurons. The present study provides further insight into the interactions within the brain between the anti-inflammatory cytokine IL-10, the inflammatory consequences of LPS, and neuropeptides known to regulate energy expenditure and food intake.
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Affiliation(s)
- Jacob H Hollis
- Department of Physiology, Monash University, Victoria, Australia.
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Bonnet MS, Pecchi E, Trouslard J, Jean A, Dallaporta M, Troadec JD. Central nesfatin-1-expressing neurons are sensitive to peripheral inflammatory stimulus. J Neuroinflammation 2009; 6:27. [PMID: 19778412 PMCID: PMC2762958 DOI: 10.1186/1742-2094-6-27] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Accepted: 09/24/2009] [Indexed: 12/05/2022] Open
Abstract
Recently, a novel factor with anorexigenic properties was identified and called nesfatin-1. This protein (82 aac) is not only expressed in peripheral organs but it is also found in neurons located in specific structures including the hypothalamus and the brainstem, two sites strongly involved in food intake regulation. Here, we studied whether some of the neurons that become activated following an injection of an anorectic dose of lipopolysaccharides (LPS) exhibit a nesfatin-1 phenotype. To this end, we used double immunohistochemistry to target the expression of the immediate-early gene c-fos and of nesfatin-1 on coronal frozen sections of the rat brain. The number of c-Fos+/nesfatin-1+ neurons was evaluated in the immunosensitive structures reported to contain nesfatin-1 neurons; i.e. paraventricular hypothalamic nucleus (PVN), supraoptic nucleus (SON), arcuate nucleus (ARC) and nucleus of the solitary tract (NTS). LPS strongly increased the number of c-Fos+/nesfatin-1+ neurons in the PVN, SON and NTS, and to a lesser extent in the ARC. Triple labeling showed that a portion of the nesfatin-1 neurons activated in response to LPS within the NTS are catecholaminergic since they co-express tyrosine hydroxylase (TH). Our data therefore indicate that a portion of nesfatin-1 neurons of both the hypothalamus and brainstem are sensitive to peripheral inflammatory signals, and provide the first clues suggesting that centrally released nesfatin-1 may contribute to the neural mechanisms leading to endotoxaemic anorexia.
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Affiliation(s)
- Marion S Bonnet
- Centre de Recherche en Neurobiologie-Neurophysiologie de Marseille (CRN2M), UMR 6231 CNRS, Marseille, France
- Département de Physiologie Neurovégétative, USC INRA 2027, Université Paul Cézanne, Université de la Méditerranée, Marseille, France
| | - Emilie Pecchi
- Centre de Recherche en Neurobiologie-Neurophysiologie de Marseille (CRN2M), UMR 6231 CNRS, Marseille, France
- Département de Physiologie Neurovégétative, USC INRA 2027, Université Paul Cézanne, Université de la Méditerranée, Marseille, France
| | - Jérôme Trouslard
- Centre de Recherche en Neurobiologie-Neurophysiologie de Marseille (CRN2M), UMR 6231 CNRS, Marseille, France
- Département de Physiologie Neurovégétative, USC INRA 2027, Université Paul Cézanne, Université de la Méditerranée, Marseille, France
| | - André Jean
- Centre de Recherche en Neurobiologie-Neurophysiologie de Marseille (CRN2M), UMR 6231 CNRS, Marseille, France
- Département de Physiologie Neurovégétative, USC INRA 2027, Université Paul Cézanne, Université de la Méditerranée, Marseille, France
| | - Michel Dallaporta
- Centre de Recherche en Neurobiologie-Neurophysiologie de Marseille (CRN2M), UMR 6231 CNRS, Marseille, France
- Département de Physiologie Neurovégétative, USC INRA 2027, Université Paul Cézanne, Université de la Méditerranée, Marseille, France
| | - Jean-Denis Troadec
- Centre de Recherche en Neurobiologie-Neurophysiologie de Marseille (CRN2M), UMR 6231 CNRS, Marseille, France
- Département de Physiologie Neurovégétative, USC INRA 2027, Université Paul Cézanne, Université de la Méditerranée, Marseille, France
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Pecchi É, Dallaporta M, Thirion S, Jean A, Denis Troadec J. La mPGES-1 : elle nous rend malades ! Med Sci (Paris) 2009; 25:451-4. [DOI: 10.1051/medsci/2009255451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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O'Banion MK. Prostaglandin E2 synthases in neurologic homeostasis and disease. Prostaglandins Other Lipid Mediat 2009; 91:113-7. [PMID: 19393332 DOI: 10.1016/j.prostaglandins.2009.04.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2009] [Revised: 04/10/2009] [Accepted: 04/10/2009] [Indexed: 01/17/2023]
Abstract
Prostaglandin E(2) synthases (PGES) currently comprise a group of three structurally and biologically distinct molecules. These enzymes are part of an important and complex paracrine signaling system involved in a wide range of biological processes. This review focuses on the normal physiological and pathological roles of these enzymes in the nervous system. Specific topics include the role of PGES(s) in fever and sickness behavior, inflammatory pain, and neural disease. Although the field is in its early stages, ongoing development of selective PGES inhibitors for possible use in people creates a significant need for more fully understanding the biological roles of these important enzymes.
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Affiliation(s)
- M Kerry O'Banion
- Department of Neurobiology & Anatomy, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
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Pecchi E, Dallaporta M, Jean A, Thirion S, Troadec JD. Prostaglandins and sickness behavior: old story, new insights. Physiol Behav 2009; 97:279-92. [PMID: 19275907 DOI: 10.1016/j.physbeh.2009.02.040] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 02/23/2009] [Accepted: 02/26/2009] [Indexed: 12/31/2022]
Abstract
Previous evidence has shown that prostaglandins play a key role in the development of sickness behavior observed during inflammatory states. In particular, prostaglandin E2 (PGE2) is produced in the brain by a variety of inflammatory signals such as endotoxins or cytokines. Its injection has been also shown to induce symptoms of sickness behavior. The role of cyclooxygenase enzymes (COX), the rate-limiting enzymes converting arachidonic acid into prostaglandins, in sickness behavior has been extensively studied, and it has been demonstrated that strategies aiming at inhibiting these enzymes limit anorexia, body weight loss and fever in animals with inflammatory diseases. However, inhibiting COX activity may lead to negative gastric or cardiovascular effects, since COX enzymes play a role in the synthesis of others prostanoids with various and sometimes contrasting properties. Recently, prostaglandin E synthases (PGES), which specifically catalyze the final step of PGE2 biosynthesis, were characterized. Among these enzymes, the microsomal prostaglandin E synthase-1 (mPGES-1) was of a particular interest since it was shown to be up-regulated by inflammatory signals in a variety of cell types. Moreover, mPGES-1 was shown to be crucial for correct immune-to-brain communication and induction of fever and anorexia by pro-inflammatory agents. This review takes stock of previous knowledge and recent advances in understanding the role of prostaglandins and of their specific synthesizing enzymes in the molecular mechanisms underlying sickness behavior. The review concludes with a short summary of key questions that remain to be addressed and points out therapeutic developments in this research field.
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Affiliation(s)
- Emilie Pecchi
- Centre de Recherche en Neurobiologie-Neurophysiologie de Marseille, UMR 6231 CNRS, USC INRA 2027, Université Paul Cézanne et Université de la Méditerranée, Marseille, France
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Inducible prostaglandin E2 synthesis interacts in a temporally supplementary sequence with constitutive prostaglandin-synthesizing enzymes in creating the hypothalamic-pituitary-adrenal axis response to immune challenge. J Neurosci 2009; 29:1404-13. [PMID: 19193887 DOI: 10.1523/jneurosci.5247-08.2009] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Inflammation-induced activation of the hypothalamic-pituitary-adrenal (HPA) axis has been suggested to depend on prostaglandins, but the prostaglandin species and the prostaglandin-synthesizing enzymes that are responsible have not been fully identified. Here, we examined HPA axis activation in mice after genetic deletion or pharmacological inhibition of prostaglandin E(2)-synthesizing enzymes, including cyclooxygenase-1 (Cox-1), Cox-2, and microsomal prostaglandin E synthase-1 (mPGES-1). After immune challenge by intraperitoneal injection of lipopolysaccharide, the rapid stress hormone responses were intact after Cox-2 inhibition and unaffected by mPGES-1 deletion, whereas unselective Cox inhibition blunted these responses, implying the involvement of Cox-1. However, mPGES-1-deficient mice showed attenuated transcriptional activation of corticotropin-releasing hormone (CRH) that was followed by attenuated plasma concentrations of adrenocorticotropic hormone and corticosterone. Cox-2 inhibition similarly blunted the delayed corticosterone response and further attenuated corticosterone release in mPGES-1 knock-out mice. The expression of the c-fos gene, an index of synaptic activation, was maintained in the paraventricular hypothalamic nucleus and its brainstem afferents both after unselective and Cox-2 selective inhibition as well as in Cox-1, Cox-2, and mPGES-1 knock-out mice. These findings point to a mechanism by which (1) neuronal afferent signaling via brainstem autonomic relay nuclei and downstream Cox-1-dependent prostaglandin release and (2) humoral, CRH transcription-dependent signaling through induced Cox-2 and mPGES-1 elicited PGE(2) synthesis, shown to occur in brain vascular cells, play distinct, but temporally supplementary roles for the stress hormone response to inflammation.
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Rorato R, Menezes AM, Giusti-Paiva A, De Castro M, Antunes-Rodrigues J, Elias LLK. Prostaglandin mediates endotoxaemia-induced hypophagia by activation of pro-opiomelanocortin and corticotrophin-releasing factor neurons in rats. Exp Physiol 2009; 94:371-9. [DOI: 10.1113/expphysiol.2008.045435] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Furuyashiki T, Narumiya S. Roles of prostaglandin E receptors in stress responses. Curr Opin Pharmacol 2009; 9:31-8. [DOI: 10.1016/j.coph.2008.12.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 11/25/2008] [Accepted: 12/01/2008] [Indexed: 11/26/2022]
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Pecchi E, Dallaporta M, Jean A, Thirion S, Troadec JD. mPGES-1 knock-out mice are resistant to cancer-induced anorexia despite the absence of central mPGES-1 up-regulation in wild-type anorexic mice. J Neuroimmunol 2008; 199:104-14. [PMID: 18602702 DOI: 10.1016/j.jneuroim.2008.05.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Revised: 05/21/2008] [Accepted: 05/21/2008] [Indexed: 12/27/2022]
Abstract
Anorexia-cachexia syndrome is a very common symptom observed in individuals affected by chronic inflammatory diseases. The present study was designed to address the possible involvement of the inducible microsomal prostaglandin E synthase-1 (mPGES-1) in the hypopaghia observed during these pathological states. To this end, we used a model of cancer-induced anorexia and we report here that despite the absence of up-regulation of the mPGES-1 enzyme within the brain during anorexia-cachexia syndrome, mPGES-1 knock-out mice exhibit resistance to tumor-induced anorexia and maintain their body mass.
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Affiliation(s)
- E Pecchi
- Centre de Recherche en Neurobiologie-Neurophysiologie de Marseille (CRN2M), UMR 6231 CNRS, Université Paul Cézanne and Université de la Méditerranée, Marseille, France
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