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Zhou W, Dai Y, Meng J, Wang P, Wu Y, Dai L, Zhang M, Yang X, Xu S, Sui F, Huo H. Network pharmacology integrated with molecular docking reveals the common experiment-validated antipyretic mechanism of bitter-cold herbs. JOURNAL OF ETHNOPHARMACOLOGY 2021; 274:114042. [PMID: 33775806 DOI: 10.1016/j.jep.2021.114042] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/11/2021] [Accepted: 03/13/2021] [Indexed: 06/12/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Bitter-cold herbs have been used to clearing heat and expelling damp in clinical practice in China for thousands of years. AIM OF THE STUDY This study aimed to investigate the common molecular mechanism of bitter-cold herbs through network pharmacology analysis, molecular docking and experimental validation in vivo. MATERIALS AND METHODS Network pharmacological analysis integrated with molecular docking was employed to identify the active compounds and core action targets of the bitter-cold herbs. Then, the yeast-induced pathological model was established, and the antipyretic effect of the herbs was evaluated by checking rectal temperatures of the mice hourly. Lastly, the protein expression of core targets was examined to reveal the antipyretic mechanism. RESULTS A total of 52 lead compounds from the four bitter-cold herbs, Phellodendri Chinensis Cortex (PCC), Sophorae Flavescentis Radix (SFR), Gentianae Radix Et Rhozima (GRER) and Coptidis Rhizoma (CR), and 248 compounds-related targets were screened out with PTGS2 ranking the first. The results from molecular docking showed that 22 compounds adopted the same orientation as aspirin and had an excellent stability in the active site pocket of PTGS2. Furthermore, these herbs exerted potential therapeutic effects through 38 related pathways. On the other hand, the outcome of animal experiments showed that they could significantly attenuate the yeast-induced mice fever with dose-dependent relationship. Further experimental results demonstrated that administration of yeast suspension raised protein expression of PTGS2 significantly, which was evidently inhibited in the high or low-dose groups of GRER as well as in the low-dose group of SFR (P < 0.01) though a higher expression of PTGS2 was shown in the low-dose group of CR compared with FM group (P < 0.01). CONCLUSIONS The bitter-cold herbs can alleviate fever response and their antipyretic effect may mainly be attributed to regulating the expression of PTGS2 after the formation of ligand-receptor/PTGS2 complexes, and their active compounds might be nominated as antipyretic lead-ligand candidates.
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Affiliation(s)
- Weiwei Zhou
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Yifei Dai
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Jing Meng
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Pengqian Wang
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Yin Wu
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Li Dai
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Miao Zhang
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Xiujuan Yang
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Shujun Xu
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Feng Sui
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
| | - Hairu Huo
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
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Pace S, Werz O. Impact of Androgens on Inflammation-Related Lipid Mediator Biosynthesis in Innate Immune Cells. Front Immunol 2020; 11:1356. [PMID: 32714332 PMCID: PMC7344291 DOI: 10.3389/fimmu.2020.01356] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 05/27/2020] [Indexed: 12/21/2022] Open
Abstract
Rheumatoid arthritis, asthma, allergic rhinitis and many other disorders related to an aberrant immune response have a higher incidence and severity in women than in men. Emerging evidences from scientific studies indicate that the activity of the immune system is superior in females and that androgens may act as “immunosuppressive” molecules with inhibitory effects on inflammatory reactions. Among the multiple factors that contribute to the inflammatory response, lipid mediators (LM), produced from polyunsaturated fatty acids, represent a class of bioactive small molecules with pivotal roles in the onset, maintenance and resolution of inflammation. LM encompass pro-inflammatory eicosanoids and specialized pro-resolving mediators (SPM) that coexist in a tightly regulated balance necessary for the return to homeostasis. Innate immune cells including neutrophils, monocytes and macrophages possess high capacities to generate distinct LM. In the last decades it became more and more evident that sex represents an important variable in the regulation of inflammation where sex hormones play crucial roles. Recent findings showed that the biosynthesis of inflammation-related LM is sex-biased and that androgens impact LM formation with consequences not only for pathophysiology but also for pharmacotherapy. Here, we review the modulation of the inflammatory response by sex and androgens with a specific focus on LM pathways. In particular, we highlight the impact of androgens on the biosynthetic pathway of inflammation-related eicosanoids in innate immune cells.
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Affiliation(s)
- Simona Pace
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Friedrich Schiller University, Jena, Germany
| | - Oliver Werz
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Friedrich Schiller University, Jena, Germany
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3
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Brito HO, Radulski D, Wilhelms DB, Stojakovic A, Brito LMO, Gil da Costa RM, Trindade E, Engblom D, Franco CRC, Zampronio AR. Immune-mediated febrile response in female rats: Role of central hypothalamic mediators. Sci Rep 2020; 10:4073. [PMID: 32139801 PMCID: PMC7058003 DOI: 10.1038/s41598-020-61210-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 02/11/2020] [Indexed: 11/24/2022] Open
Abstract
Lipopolysaccharide (LPS) induces fever through cytokines like receptor-activator of nuclear factor κB ligand (RANKL), triggering mediators like prostaglandins (PG), endothelin-1 (ET-1), corticotrophin-releasing factor (CRF), substance P (SP) and endogenous opioids. LPS-induced fever is reduced in females compared with males except in ovariectomized (OVX) females which show increased fever mediated by PG. The present study aimed to identify the mediators involved in fever in intact and OVX female rats. Fever was induced with LPS (50 μg/kg) intraperitoneally or CRF (2.5 μg), ET-1 (1 pg), morphine (10 μg) and SP (500 ng) intracerebroventricularly in sham-operated and OVX rats. The role of RANKL was evaluated with osteoprotegerin (OPG, 1 μg, intracerebroventricularly). Expression of RANK, CRFI/II, ETB, μ-opioid (MOR) and NK1 receptors was evaluated by confocal microscopy. Besides LPS, only morphine induced fever in OVX rats while all mediators induced fever in sham-operated animals. OPG abolished LPS-induced fever in OVX but not sham-operated animals. Overall, fever involves similar central mediators in cycling females and males but only morphine induced fever in OVX females. Importantly, RANK/RANKL participates in LPS-induced fever in OVX females, as in males but not in cycling females.
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Affiliation(s)
| | - Débora Radulski
- Department of Pharmacology, Federal University of Paraná, Curitiba, PR, Brazil
| | | | | | | | | | - Edvaldo Trindade
- Department of Pharmacology, Federal University of Paraná, Curitiba, PR, Brazil
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Grattan DR, Ladyman SR. Neurophysiological and cognitive changes in pregnancy. HANDBOOK OF CLINICAL NEUROLOGY 2020; 171:25-55. [PMID: 32736755 DOI: 10.1016/b978-0-444-64239-4.00002-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The hormonal fluctuations in pregnancy drive a wide range of adaptive changes in the maternal brain. These range from specific neurophysiological changes in the patterns of activity of individual neuronal populations, through to complete modification of circuit characteristics leading to fundamental changes in behavior. From a neurologic perspective, the key hormone changes are those of the sex steroids, estradiol and progesterone, secreted first from the ovary and then from the placenta, the adrenal glucocorticoid cortisol, as well as the anterior pituitary peptide hormone prolactin and its pregnancy-specific homolog placental lactogen. All of these hormones are markedly elevated during pregnancy and cross the blood-brain barrier to exert actions on neuronal populations through receptors expressed in specific regions. Many of the hormone-induced changes are in autonomic or homeostatic systems. For example, patterns of oxytocin and prolactin secretion are dramatically altered to support novel physiological functions. Appetite is increased and feedback responses to metabolic hormones such as leptin and insulin are suppressed to promote a positive energy balance. Fundamental physiological systems such as glucose homeostasis and thermoregulation are modified to optimize conditions for fetal development. In addition to these largely autonomic changes, there are also changes in mood, behavior, and higher processes such as cognition. This chapter summarizes the hormonal changes associated with pregnancy and reviews how these changes impact on brain function, drawing on examples from animal research, as well as available information about human pregnancy.
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Affiliation(s)
- David R Grattan
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
| | - Sharon R Ladyman
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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5
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Barrientos RM, Brunton PJ, Lenz KM, Pyter L, Spencer SJ. Neuroimmunology of the female brain across the lifespan: Plasticity to psychopathology. Brain Behav Immun 2019; 79:39-55. [PMID: 30872093 PMCID: PMC6591071 DOI: 10.1016/j.bbi.2019.03.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/25/2019] [Accepted: 03/09/2019] [Indexed: 02/06/2023] Open
Abstract
The female brain is highly dynamic and can fundamentally remodel throughout the normal ovarian cycle as well as in critical life stages including perinatal development, pregnancy and old-age. As such, females are particularly vulnerable to infections, psychological disorders, certain cancers, and cognitive impairments. We will present the latest evidence on the female brain; how it develops through the neonatal period; how it changes through the ovarian cycle in normal individuals; how it adapts to pregnancy and postpartum; how it responds to illness and disease, particularly cancer; and, finally, how it is shaped by old age. Throughout, we will highlight female vulnerability to and resilience against disease and dysfunction in the face of environmental challenges.
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Affiliation(s)
- R M Barrientos
- Institute for Behavioral Medicine Research, Wexner Medical Centre, The Ohio State University, Columbus, OH 43210, United States; Department of Psychiatry and Behavioral Health, Wexner Medical Centre, The Ohio State University, Columbus, OH 43210, United States; Chronic Brain Injury Program, Discovery Themes Initiative, The Ohio State University, Columbus, OH 43210, United States
| | - P J Brunton
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, Scotland, UK; Zhejiang University-University of Edinburgh Joint Institute, Zhejiang University School of Medicine, International Campus, Haining, Zhejiang 314400, PR China
| | - K M Lenz
- Institute for Behavioral Medicine Research, Wexner Medical Centre, The Ohio State University, Columbus, OH 43210, United States; Department of Psychology, Department of Neuroscience, The Ohio State University, Columbus, OH 43210, United States
| | - L Pyter
- Institute for Behavioral Medicine Research, Wexner Medical Centre, The Ohio State University, Columbus, OH 43210, United States; Department of Psychiatry and Behavioral Health, Wexner Medical Centre, The Ohio State University, Columbus, OH 43210, United States
| | - S J Spencer
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic. 3083, Australia.
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Pace S, Sautebin L, Werz O. Sex-biased eicosanoid biology: Impact for sex differences in inflammation and consequences for pharmacotherapy. Biochem Pharmacol 2017. [PMID: 28647490 DOI: 10.1016/j.bcp.2017.06.128] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The incidence, severity and progression of autoimmune diseases (e.g. scleroderma, multiple sclerosis, rheumatoid arthritis) and certain inflammatory diseases (e.g. asthma) are sex-biased where these pathologies dominate in women. However, other immune disorders such as sepsis, post-surgery infections and gout display higher incidence and severity in men. The molecular and cellular basis underlying this sex dimorphism remains incompletely elucidated but may provide important insights for sex-specific pharmacotherapy. Nevertheless, the sex as a variable in biochemical and preclinical research on inflammation is often neglected. Thus, respective animal studies are routinely performed with males, and experiments with isolated cells rarely report the sex of the donor. However, sex differences on the cellular level do exist, in particular related to inflammatory processes that prompt for sex-specific appreciation of inflammation research. For instance, the biosynthesis of pro-inflammatory eicosanoids is sex-biased where leukotriene (LT) formation is under control of testosterone that regulates the subcellular localization of the key enzyme 5-lipoxygenase, with possible implications for gender-tailored pharmacotherapy of LT-related disorders (i.e. asthma). Moreover, prostaglandin (PG) production is sex-biased, and sex-dependent efficacy of aspirin was evident in several clinical trials. Here, we highlight the sex bias in eicosanoid biology possibly underlying the obvious sex disparities in inflammation, stimulating scientists to take sex into account when studying the pathophysiology and pharmacotherapy of inflammatory diseases.
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Affiliation(s)
- Simona Pace
- Institute of Pharmacy, Friedrich-Schiller-University Jena, Philosophenweg 14, D-07743 Jena, Germany.
| | - Lidia Sautebin
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Via D. Montesano, 49 - 80131 Naples, Italy.
| | - Oliver Werz
- Institute of Pharmacy, Friedrich-Schiller-University Jena, Philosophenweg 14, D-07743 Jena, Germany.
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7
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Brito HO, Radulski DR, Wilhelms DB, Stojakovic A, Brito LMO, Engblom D, Franco CRC, Zampronio AR. Female Sex Hormones Influence the Febrile Response Induced by Lipopolysaccharide, Cytokines and Prostaglandins but not by Interleukin-1β in Rats. J Neuroendocrinol 2016; 28. [PMID: 27483048 DOI: 10.1111/jne.12414] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 07/05/2016] [Accepted: 07/29/2016] [Indexed: 11/26/2022]
Abstract
There are differences in the immune response, and particularly fever, between males and females. In the present study, we investigated how the febrile responses induced by lipopolysaccharide (LPS) and different endogenous pyrogens were affected by female gonadal hormones. The febrile response to i.p. injection of LPS (50 μg/kg) was 40% lower in female rats compared to male or ovariectomised (OVX) female rats. Accordingly, oestrogen replacement in OVX animals reduced LPS-induced fever. Treatment with the prostaglandin synthesis inhibitor indomethacin (2 mg/kg, i.p. 30 min before) reduced the febrile response induced by LPS in both OVX (88%) and sham-operated (71%) rats. In line with the enhanced fever in OVX rats, there was increased expression of cyclooxygenase-2 (COX-2) in the hypothalamus and elevated levels of prostaglandin E2 (PGE2 ). In addition, OVX rats were hyper-responsive to PGE2 injected i.c.v. By contrast to the enhanced fever in response to LPS and PGE2 , the febrile response induced by i.c.v. injection of interleukin (IL)-1β was unaffected by ovariectomy, whereas the responses induced by tumour necrosis factor (TNF)-α and macrophage inflammatory protein (MIP)-1α were completely abrogated. These results suggest that the mediators involved in the febrile response in females are similar to males, although the reduction of female hormones may decrease the responsiveness of some mediators such as TNF-α and MIP-1α. Compensatory mechanisms may be activated in females after ovariectomy such as an augmented synthesis of COX-2 and PGE2 .
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Affiliation(s)
- H O Brito
- Department of Pharmacology, Federal University of Paraná, Curitiba, Brazil
| | - D R Radulski
- Department of Pharmacology, Federal University of Paraná, Curitiba, Brazil
| | - D B Wilhelms
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - A Stojakovic
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - L M O Brito
- Department of Medicine III, Federal University of Maranhão, São Luís, Brazil
| | - D Engblom
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - C R C Franco
- Department of Cell Biology, Federal University of Paraná, Curitiba, Brazil
| | - A R Zampronio
- Department of Pharmacology, Federal University of Paraná, Curitiba, Brazil.
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8
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Foster J, Mauger AR, Chrismas BCR, Thomasson K, Taylor L. Is prostaglandin E2 (PGE2) involved in the thermogenic response to environmental cooling in healthy humans? Med Hypotheses 2015; 85:607-11. [PMID: 26253311 DOI: 10.1016/j.mehy.2015.07.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 07/20/2015] [Accepted: 07/25/2015] [Indexed: 12/12/2022]
Abstract
Prostaglandin E2 (PGE2) is an eicosanoid derived from cyclooxygenase, an enzyme responsible for the cyclisation and oxygenation of arachidonic acid. In response to bacterial infection, PGE2 binds to EP3 receptors on a population of GABAergic neurons in the pre-optic area. Activation of the EP3 receptor decreases the intracellular cyclic adenosine monophosphate (cAMP) concentrations of these neurons, and the resulting dis-inhibition activates spinal motor outputs responsible for shivering thermogenesis, tachycardia, and brown adipose tissue activation. These involuntary responses increase core body temperature to varying degrees depending on the magnitude of infection; an immune response which is crucial for the survival of the host. However, evidence in animal and human models, primarily through the use of cyclooxygenase inhibitors (which block the production of PGE2), suggests that PGE2 may also be an important molecule for the defence of core temperature against body cooling and cold stress (in the absence of fever). In this paper, evidence within human and animal models is discussed which supports the hypothesis that the eicosanoid PGE2 has a role in maintaining human core temperature during environmental cooling. Given that over-the-counter PGE2 inhibiting drugs [i.e. Non-Steroidal Anti Inflammatory Drugs (NSAIDS)] are frequently used worldwide, it is possible that the use of such medication during environmental cooling could impair one's ability to thermoregulate. Support for such findings could have major implications in the pathology of hypothermia, thus, we suggest that future researchers investigate this specific hypothesis in vivo, using healthy human models. Suggestions for the implementation of such experiments are provided in the present work.
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Affiliation(s)
- Josh Foster
- Applied Sport and Exercise Physiology (ASEP) Research Group, Institute of Sport and Physical Activity Research (ISPAR), Department of Sport and Exercise Sciences, University of Bedfordshire, Bedford, UK
| | - Alexis R Mauger
- Endurance Research Group, School of Sport and Exercise Sciences, University of Kent, Chatham Maritime, UK
| | - Bryna C R Chrismas
- Applied Sport and Exercise Physiology (ASEP) Research Group, Institute of Sport and Physical Activity Research (ISPAR), Department of Sport and Exercise Sciences, University of Bedfordshire, Bedford, UK
| | - Katie Thomasson
- Applied Sport and Exercise Physiology (ASEP) Research Group, Institute of Sport and Physical Activity Research (ISPAR), Department of Sport and Exercise Sciences, University of Bedfordshire, Bedford, UK
| | - Lee Taylor
- Applied Sport and Exercise Physiology (ASEP) Research Group, Institute of Sport and Physical Activity Research (ISPAR), Department of Sport and Exercise Sciences, University of Bedfordshire, Bedford, UK.
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Roth J, Blatteis CM. Mechanisms of fever production and lysis: lessons from experimental LPS fever. Compr Physiol 2015; 4:1563-604. [PMID: 25428854 DOI: 10.1002/cphy.c130033] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Fever is a cardinal symptom of infectious or inflammatory insults, but it can also arise from noninfectious causes. The fever-inducing agent that has been used most frequently in experimental studies designed to characterize the physiological, immunological and neuroendocrine processes and to identify the neuronal circuits that underlie the manifestation of the febrile response is lipopolysaccharide (LPS). Our knowledge of the mechanisms of fever production and lysis is largely based on this model. Fever is usually initiated in the periphery of the challenged host by the immediate activation of the innate immune system by LPS, specifically of the complement (C) cascade and Toll-like receptors. The first results in the immediate generation of the C component C5a and the subsequent rapid production of prostaglandin E2 (PGE2). The second, occurring after some delay, induces the further production of PGE2 by induction of its synthesizing enzymes and transcription and translation of proinflammatory cytokines. The Kupffer cells (Kc) of the liver seem to be essential for these initial processes. The subsequent transfer of the pyrogenic message from the periphery to the brain is achieved by neuronal and humoral mechanisms. These pathways subserve the genesis of early (neuronal signals) and late (humoral signals) phases of the characteristically biphasic febrile response to LPS. During the course of fever, counterinflammatory factors, "endogenous antipyretics," are elaborated peripherally and centrally to limit fever in strength and duration. The multiple interacting pro- and antipyretic signals and their mechanistic effects that underlie endotoxic fever are the subjects of this review.
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Affiliation(s)
- Joachim Roth
- Department of Veterinary Physiology and Biochemistry, Justus-Liebig-University, Giessen, Germany; Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee
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Lu L, Zhang Q, Wu K, Chen X, Zheng Y, Zhu C, Wu J. Hepatitis C virus NS3 protein enhances cancer cell invasion by activating matrix metalloproteinase-9 and cyclooxygenase-2 through ERK/p38/NF-κB signal cascade. Cancer Lett 2014; 356:470-8. [PMID: 25305454 DOI: 10.1016/j.canlet.2014.09.027] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 09/06/2014] [Accepted: 09/22/2014] [Indexed: 12/17/2022]
Abstract
Hepatitis C virus (HCV) infection causes acute and chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). However, the mechanisms by which HCV causes the diseases are largely unknown. Here, we elucidated the effects of HCV on the invasion and migration of hepatoma cells, with the aim to reveal the mechanism by which HCV infection induces HCC. We initially showed that matrix metalloproteinase-9 (MMP-9) was elevated in the sera of HCV-infected patients, and demonstrated that HCV nonstructural protein 3 (NS3) activated MMP-9 transcription through nuclear factor-κB (NF-κB) by stimulating translocation of NF-κB from cytosol to the nucleus to enhance its binding to MMP-9 promoter. In addition, cyclooxygenase-2 (COX-2) and extracellular signal-regulated kinase (ERK1/2)/mitogen-activated protein kinase (p38) pathway were involved in HCV-activated MMP-9 expression. Moreover, NS3 enhanced hepatoma cell invasion and migration through MMP-9 and COX-2. Thus, this study provides new insights into the roles of HCV NS3, MMP-9 and COX-2 in regulating cancer cell invasion.
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Affiliation(s)
- Lili Lu
- State Key Laboratory of Virology and College of Life Sciences, Wuhan University, Wuhan 430072, China; Wuhan University of Science and Technology, Wuhan 430081, China
| | - Qi Zhang
- State Key Laboratory of Virology and College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Kailang Wu
- State Key Laboratory of Virology and College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xi Chen
- State Key Laboratory of Virology and College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yi Zheng
- State Key Laboratory of Virology and College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Chengliang Zhu
- State Key Laboratory of Virology and College of Life Sciences, Wuhan University, Wuhan 430072, China; Renmin Hospital, Wuhan University, Wuhan 430060, China
| | - Jianguo Wu
- State Key Laboratory of Virology and College of Life Sciences, Wuhan University, Wuhan 430072, China.
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Shukla S, Bafna K, Sundar D, Thorat SS. The bitter barricading of prostaglandin biosynthesis pathway: understanding the molecular mechanism of selective cyclooxygenase-2 inhibition by amarogentin, a secoiridoid glycoside from Swertia chirayita. PLoS One 2014; 9:e90637. [PMID: 24603686 PMCID: PMC3946170 DOI: 10.1371/journal.pone.0090637] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Accepted: 02/04/2014] [Indexed: 12/24/2022] Open
Abstract
Swertia chirayita, a medicinal herb inhabiting the challenging terrains and high altitudes of the Himalayas, is a rich source of essential phytochemical isolates. Amarogentin, a bitter secoiridoid glycoside from S. chirayita, shows varied activity in several patho-physiological conditions, predominantly in leishmaniasis and carcinogenesis. Experimental analysis has revealed that amarogentin downregulates the cyclooxygenase-2 (COX-2) activity and helps to curtail skin carcinogenesis in mouse models; however, there exists no account on selective inhibition of the inducible cyclooxygenase (COX) isoform by amarogentin. Hence the computer-aided drug discovery methods were used to unravel the COX-2 inhibitory mechanism of amarogentin and to check its selectivity for the inducible isoform over the constitutive one. The generated theoretical models of both isoforms were subjected to molecular docking analysis with amarogentin and twenty-one other Food and Drug Authority (FDA) approved lead molecules. The post-docking binding energy profile of amarogentin was comparable to the binding energy profiles of the FDA approved selective COX-2 inhibitors. Subsequent molecular dynamics simulation analysis delineated the difference in the stability of both complexes, with amarogentin-COX-2 complex being more stable after 40ns simulation. The total binding free energy calculated by MMGBSA for the amarogentin-COX-2 complex was −52.35 KCal/mol against a binding free energy of −8.57 KCal/mol for amarogentin-COX-1 complex, suggesting a possible selective inhibition of the COX-2 protein by the natural inhibitor. Amarogentin achieves this potential selectivity by small, yet significant, structural differences inherent to the binding cavities of the two isoforms. Hypothetically, it might block the entry of the natural substrates in the hydrophobic binding channel of the COX-2, inhibiting the cyclooxygenation step. To sum up briefly, this work highlights the mechanism of the possible selective COX-2 inhibition by amarogentin and endorses the possibility of obtaining efficient, futuristic and targeted therapeutic agents for relieving inflammation and malignancy from this phytochemical source.
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Affiliation(s)
- Shantanu Shukla
- Bioresource Database and Bioinformatics Division, Regional Center of Institute of Bioresources and Sustainable Development, Tadong, Gangtok, Sikkim, India
| | - Khushboo Bafna
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, India
| | - Durai Sundar
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, India
- * E-mail: (SST); (DS)
| | - Sunil S. Thorat
- Bioresource Database and Bioinformatics Division, Regional Center of Institute of Bioresources and Sustainable Development, Tadong, Gangtok, Sikkim, India
- Distributed Information Sub-Centre, Institute of Bioresources and Sustainable Development, Imphal, Manipur, India
- * E-mail: (SST); (DS)
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12
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Pohl J, Luheshi GN, Woodside B. Effect of obesity on the acute inflammatory response in pregnant and cycling female rats. J Neuroendocrinol 2013; 25:433-45. [PMID: 23331909 DOI: 10.1111/jne.12023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 12/31/2012] [Accepted: 01/10/2013] [Indexed: 12/18/2022]
Abstract
Nonpregnant female rats have a lower inflammatory response to lipopolysaccharide (LPS) than males and, at late stages of gestation, the fever response to this immunogen is almost completely suppressed. We have shown in males that obesity exacerbates sickness responses to pathogenic stimuli. In the present study, we investigated whether obesity would have a similar effect in females and reverse some of the suppressive effects of pregnancy on the innate immune response. Lean and diet-induced obese adult Wistar rats were randomly separated into either cycling or mated groups. On day 18 of pregnancy or in the metestrous/dioestrous phase in cycling rats, a single injection of LPS (100 μg/kg) was administered and rats were sacrificed 8h or 24 h later. In pregnant females, LPS induced a higher increase in body temperature in obese rats only at the 24-h time point and lower hypothalamic interleukin (IL)-1β expression and higher circulating levels of IL-1 receptor antagonist (ra) than their cycling counterparts. Conversely, there was no suppression of inflammatory signals in the white adipose tissue of pregnant rats. At 24 h post LPS, the cell surface marker CD11c and IL-6 mRNA expression were increased in white adipose tissue from obese rats regardless of reproductive state, whereas IL-1ra was highest in the LPS-treated obese pregnant group. In cycling females, LPS induced a higher fever response in obese rats accompanied by higher circulating levels of IL-6 and IL-1ra, as well as an increase in circulating leptin only in the obese cycling group. In the hypothalamus, obese rats showed significantly higher expression of nuclear factor-IL-6 in at the 8-h time point. Collectively, these results show that diet-induced obesity in females is associated with a similar pattern of response to that previously observed in males. On the other hand, obesity had limited effects in pregnant rats, with the exception of white adipose tissue.
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Affiliation(s)
- J Pohl
- Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
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13
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Mouihate A, Al-Bader MD. Glucocorticoid-induced fetal brain growth restriction is associated with p73 gene activation. J Neurosci Res 2012; 91:95-104. [PMID: 23086675 DOI: 10.1002/jnr.23130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Revised: 06/13/2012] [Accepted: 07/20/2012] [Indexed: 01/22/2023]
Abstract
Fetal exposure to excessive amounts of glucocorticoids (GCs) hampers proper brain development. The molecular mechanism(s) underlying these GCs effects are not well understood. We explored the impact of fetal exposure to maternal GCs on fetal brain expression of p63 and p73 transactivation (TA) and dominant negative (ΔN) gene variants that promote neural cell death (TA) and cell survival programs (ΔN). The fetoplacental enzyme 11β-hydroxysteroid dehydrogenase 2, which shields fetuses from maternal glucocorticoids, was inhibited throughout pregnancy by daily injection of carbenoxolone to pregnant dams. The expression of p63 and p73 gene variants and proteins was monitored by real-time rtPCR and Western blot in the brains of male and female fetuses. Carbenoxolone administration led to an overall enhanced level of corticosterone in the amniotic fluid of both male and female fetuses at late pregnancy. These enhanced corticosterone levels were associated with a significant reduction in fetal brain weights and a significant increase in TAp73 mRNA and p73 protein levels. However, the expression levels of TAp63 mRNA and p63 proteins were either suppressed or unaffected. The pro-neural survival gene variant ΔNp73 was significantly reduced in female and enhanced in male fetal brains, whereas ΔNp63 was significantly reduced in the brains of both genders. These data suggest that the GCs-induced negative impact on fetal brain development likely is due, at least in part, to their action of the pro-neural cell death gene variant TAp73 and to the modulation of the pro-survival ΔNp63 and ΔNp73 gene variants in a gender-dependent fashion.
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Affiliation(s)
- Abdeslam Mouihate
- Department of Physiology, Faculty of Medicine, Kuwait University, Safat, Kuwait.
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Abdeslam M. Prenatal Immune Stress in Rats Dampens Fever during Adulthood. Dev Neurosci 2012; 34:318-26. [DOI: 10.1159/000339852] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 05/30/2012] [Indexed: 11/19/2022] Open
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15
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Early life activation of toll-like receptor 4 reprograms neural anti-inflammatory pathways. J Neurosci 2010; 30:7975-83. [PMID: 20534845 DOI: 10.1523/jneurosci.6078-09.2010] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
A single postnatal exposure to the bacterial endotoxin, lipopolysaccharide (LPS), reduces the neuroimmune response to a subsequent LPS exposure in the adult rat. The attenuated fever and proinflammatory response is caused by a paradoxical, amplified, early corticosterone response to LPS. Here we identify the mechanisms underlying the heightened corticosterone response to LPS in adults after early life exposure to LPS. In postnatal LPS-treated rats, hypothalamic corticotrophin-releasing hormone mRNA, pituitary proopiomelanocortin mRNA, and circulating adrenocorticotrophic hormone were all increased after adult exposure to LPS without significant modification to hippocampal or hypothalamic glucocorticoid receptor mRNA or protein or vagally mediated afferent signaling to the brain. Postnatal LPS administration did cause a persistent upregulation of the LPS Toll-like receptor-4 (TLR4) mRNA in liver and spleen, but not in brain, pituitary, or adrenal gland. In addition, cyclooxygenase-2 (COX-2), which is a prostaglandin biosynthetic enzyme and is normally undetectable in most peripheral tissue, was constitutively expressed in the liver. Adult immune activation of the upregulated TLR4 and COX-2 caused a rapid, amplified rise in circulating, but not brain, prostaglandin E(2) that induced an early, enhanced activation of the hypothalamic-pituitary-adrenal (HPA) axis. Thus, postnatal LPS reprograms the neuroimmune axis by priming peripheral tissues to create a novel, prostaglandin-mediated activation of the HPA axis brought about by increased constitutive expression of TLR4 and COX-2.
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Russell JA, Douglas AJ, Brunton PJ. Reduced Hypothalamo-pituitary-adrenal Axis Stress Responses in Late Pregnancy. Ann N Y Acad Sci 2008; 1148:428-38. [DOI: 10.1196/annals.1410.032] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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17
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Duncan M, Thomas AD, Cluny NL, Patel A, Patel KD, Lutz B, Piomelli D, Alexander SPH, Sharkey KA. Distribution and function of monoacylglycerol lipase in the gastrointestinal tract. Am J Physiol Gastrointest Liver Physiol 2008; 295:G1255-65. [PMID: 18948437 DOI: 10.1152/ajpgi.90500.2008] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The endogenous cannabinoid system plays an important role in the regulation of gastrointestinal function in health and disease. Endocannabinoid levels are regulated by catabolic enzymes. Here, we describe the presence and localization of monoacylglycerol lipase (MGL), the major enzyme responsible for the degradation of 2-arachidonoylglycerol. We used molecular, biochemical, immunohistochemical, and functional assays to characterize the distribution and activity of MGL. MGL mRNA was present in rat ileum throughout the wall of the gut. MGL protein was distributed in the muscle and mucosal layers of the ileum and in the duodenum, proximal colon, and distal colon. We observed MGL expression in nerve cell bodies and nerve fibers of the enteric nervous system. There was extensive colocalization of MGL with PGP 9.5 and calretinin-immunoreactive neurons, but not with nitric oxide synthase. MGL was also present in the epithelium and was highly expressed in the small intestine. Enzyme activity levels were highest in the duodenum and decreased along the gut with lowest levels in the distal colon. We observed both soluble and membrane-associated enzyme activities. The MGL inhibitor URB602 significantly inhibited whole gut transit in mice, an action that was abolished in cannabinoid 1 receptor-deficient mice. In conclusion, MGL is localized in the enteric nervous system where endocannabinoids regulate intestinal motility. MGL is highly expressed in the epithelium, where this enzyme may have digestive or other functions yet to be determined.
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Affiliation(s)
- Marnie Duncan
- Hotchkiss Brain Institute and Snyder Institute of Infection, Immunity and Inflammation, Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta, Canada
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Duncan M, Mouihate A, Mackie K, Keenan CM, Buckley NE, Davison JS, Patel KD, Pittman QJ, Sharkey KA. Cannabinoid CB2 receptors in the enteric nervous system modulate gastrointestinal contractility in lipopolysaccharide-treated rats. Am J Physiol Gastrointest Liver Physiol 2008; 295:G78-G87. [PMID: 18483180 PMCID: PMC2494728 DOI: 10.1152/ajpgi.90285.2008] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Enhanced intestinal transit due to lipopolysaccharide (LPS) is reversed by cannabinoid (CB)2 receptor agonists in vivo, but the site and mechanism of action are unknown. We have tested the hypothesis that CB2 receptors are expressed in the enteric nervous system and are activated in pathophysiological conditions. Tissues from either saline- or LPS-treated (2 h; 65 microg/kg ip) rats were processed for RT-PCR, Western blotting, and immunohistochemistry or were mounted in organ baths where electrical field stimulation was applied in the presence or absence of CB receptor agonists. Whereas the CB2 receptor agonist JWH133 did not affect the electrically evoked twitch response of the ileum under basal conditions, in the LPS-treated tissues JWH133 was able to reduce the enhanced contractile response in a concentration-dependent manner. Rat ileum expressed CB2 receptor mRNA and protein under physiological conditions, and this expression was not affected by LPS treatment. In the myenteric plexus, CB2 receptors were expressed on the majority of neurons, although not on those expressing nitric oxide synthase. LPS did not alter the distribution of CB2 receptor expression in the myenteric plexus. In vivo LPS treatment significantly increased Fos expression in both enteric glia and neurons. This enhanced expression was significantly attenuated by JWH133, whose action was reversed by the CB2 receptor antagonist AM630. Taking these facts together, we conclude that activation of CB2 receptors in the enteric nervous system of the gastrointestinal tract dampens endotoxin-induced enhanced intestinal contractility.
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Affiliation(s)
- Marnie Duncan
- Snyder Institute of Infection, Immunity and Inflammation and Hotchkiss Brain Institute, Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta, Canada; Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana; and Department of Biological Sciences, California State Polytechnic University, Pomona, California
| | - Abdeslam Mouihate
- Snyder Institute of Infection, Immunity and Inflammation and Hotchkiss Brain Institute, Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta, Canada; Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana; and Department of Biological Sciences, California State Polytechnic University, Pomona, California
| | - Ken Mackie
- Snyder Institute of Infection, Immunity and Inflammation and Hotchkiss Brain Institute, Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta, Canada; Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana; and Department of Biological Sciences, California State Polytechnic University, Pomona, California
| | - Catherine M. Keenan
- Snyder Institute of Infection, Immunity and Inflammation and Hotchkiss Brain Institute, Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta, Canada; Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana; and Department of Biological Sciences, California State Polytechnic University, Pomona, California
| | - Nancy E. Buckley
- Snyder Institute of Infection, Immunity and Inflammation and Hotchkiss Brain Institute, Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta, Canada; Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana; and Department of Biological Sciences, California State Polytechnic University, Pomona, California
| | - Joseph S. Davison
- Snyder Institute of Infection, Immunity and Inflammation and Hotchkiss Brain Institute, Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta, Canada; Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana; and Department of Biological Sciences, California State Polytechnic University, Pomona, California
| | - Kamala D. Patel
- Snyder Institute of Infection, Immunity and Inflammation and Hotchkiss Brain Institute, Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta, Canada; Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana; and Department of Biological Sciences, California State Polytechnic University, Pomona, California
| | - Quentin J. Pittman
- Snyder Institute of Infection, Immunity and Inflammation and Hotchkiss Brain Institute, Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta, Canada; Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana; and Department of Biological Sciences, California State Polytechnic University, Pomona, California
| | - Keith A. Sharkey
- Snyder Institute of Infection, Immunity and Inflammation and Hotchkiss Brain Institute, Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta, Canada; Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana; and Department of Biological Sciences, California State Polytechnic University, Pomona, California
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Mouihate A, Harré EM, Martin S, Pittman QJ. Suppression of the febrile response in late gestation: evidence, mechanisms and outcomes. J Neuroendocrinol 2008; 20:508-14. [PMID: 18266941 PMCID: PMC3547979 DOI: 10.1111/j.1365-2826.2008.01666.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Fever is a beneficial host defence response. However, fever caused by the immune stimulant, lipopolysaccharide (LPS), are attenuated in many species during pregnancy, particularly near term. A number of parallel mechanisms may be responsible, and these vary in magnitude according to the time of gestation, type of inflammatory stimulus and species of animal. Some studies report a reduction in the plasma levels of circulating pro-inflammatory cytokines such as tumour necrosis factor-alpha, interleukin-1beta and interleukin-6 along with increased levels of anti-inflammatory cytokines such as interleukin-1 receptor antagonist. Associated with the attenuated febrile response to LPS is a reduction in the activation of the prostaglandin synthesising enzyme, cyclo-oxygenase 2, resulting in reduced levels of the obligatory prostaglandin mediators of the febrile response in the brain. There is also a reduction in the sensitivity of the brain to the pyrogenic action of prostaglandins, which does not appear to be due to a change in the levels of hypothalamic EP3 prostaglandin receptors. The suppression of fever at term may be important for the health of the neonate because fever in pregnant mothers may be harmful to the late-term foetus and neonate.
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Affiliation(s)
- A Mouihate
- Department of Physiology and Biophysics, Hotchkiss Brain Institute, Institutes of Infection, Immunity and Inflammation and Maternal and Child Health, University of Calgary, Calgary, Alberta, Canada
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Spencer SJ, Mouihate A, Galic MA, Pittman QJ. Central and peripheral neuroimmune responses: hyporesponsiveness during pregnancy. J Physiol 2008; 586:399-406. [PMID: 17947311 PMCID: PMC2375585 DOI: 10.1113/jphysiol.2007.144006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Accepted: 10/05/2007] [Indexed: 11/08/2022] Open
Abstract
There are periods in the life of a healthy animal (including humans) when the febrile response to an immune challenge is suppressed. One such period is during late pregnancy, particularly around the time of parturition. In the 30 or so years since this 'febrile hyporesponsiveness' was first noted, much work has been done to investigate the mechanisms and adaptive significance of this phenomenon. In this review we present some insight into how and why the body deliberately re-programmes itself to develop smaller fevers in response to an immune challenge and therefore to be potentially less successful at fighting infection.
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Affiliation(s)
- Sarah J Spencer
- Hotchkiss Brain Institute, Department of Physiology and Biophysics, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
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21
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Tang EHC, Jensen BL, Skott O, Leung GPH, Feletou M, Man RYK, Vanhoutte PM. The role of prostaglandin E and thromboxane-prostanoid receptors in the response to prostaglandin E2 in the aorta of Wistar Kyoto rats and spontaneously hypertensive rats. Cardiovasc Res 2007; 78:130-8. [PMID: 18093985 DOI: 10.1093/cvr/cvm112] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS The present study examined the hypothesis that prostaglandin E2 (PGE2) through activation of prostaglandin E (EP) receptor contributes to endothelium-dependent contractions. METHODS AND RESULTS Western blotting revealed that the protein expression of EP1 receptor was significantly down-regulated in the aorta of the spontaneously hypertensive rat (SHR), but there was no significant difference in the expression of EP2, EP4, and total EP3 receptors between preparations of Wistar Kyoto rats (WKY) and SHR. Isometric tension studies showed that low concentrations of PGE2 caused endothelium-dependent relaxations in WKY but not in aortas of the SHR. High concentrations of PGE2 evoked contractions predominately through the activation of thromboxane-prostanoid (TP) receptors in the WKY, but involves the dual activation EP and TP receptors in the SHR. SQ29,548, BAYu3405 and Terutroban (TP receptor antagonists), and AH6809 (non-selective EP receptor antagonist) abolished, while SC19220 (preferential EP1 receptor antagonist) did not inhibit endothelium-dependent contractions. Both SC19220 and AH6809 significantly inhibited contractions to U46619 (TP receptor agonist). CONCLUSION The present study demonstrates that the contraction caused by PGE2 in the SHR aorta is dependent on the activation of EP1 and TP receptors, but that endothelium-dependent contractions do not require the former. Thus, PGE2 is unlikely to be an endothelium-derived contracting factor in this artery. The ability of AH6809 to inhibit endothelium-dependent contractions can be attributed to its partial antagonism at TP receptors. Nevertheless, the impairment of PGE2-mediated relaxation may contribute to endothelial dysfunction in the aorta of the SHR.
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Affiliation(s)
- Eva H C Tang
- Department of Pharmacology, The University of Hong Kong, 2/F, Laboratory Block, Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong
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Brunton PJ, Russell JA. Attenuated hypothalamo-pituitary-adrenal axis responses to immune challenge during pregnancy: the neurosteroid opioid connection. J Physiol 2007; 586:369-75. [PMID: 17991694 DOI: 10.1113/jphysiol.2007.146233] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In late pregnancy maternal hypothalamo-pituitary-adrenal (HPA) axis responses to emotional and physical stressors are attenuated. This is expected to minimize the detrimental programming effects of glucocorticoid exposure on the fetuses. We have utilized a model of immune challenge, systemic administration of interleukin-1beta (IL-1beta), to investigate the underlying mechanisms. Intravenous IL-1beta activates corticotropin-releasing hormone (CRH) neurones in the parvocellular division of the paraventricular nucleus (pPVN) via noradrenergic (A2 cell group) neurones in the nucleus tractus solitarii (NTS). Despite comparable activation of these brainstem neurones by IL-1beta in virgin and in late pregnant rats, pPVN CRH neurones are activated only in virgin rats. As a consequence IL-1beta fails to evoke ACTH and corticosterone secretion in late pregnant rats, in contrast to virgin rats. Suppressed responsiveness of the CRH neurones, and hence the HPA axis, following IL-1beta in late pregnancy is explained by presynaptic inhibition of noradrenaline release in the pPVN, due to increased endogenous enkephalin and mu-opioid receptor production in brainstem NTS neurones. The factor that signals to the brain the pregnancy status of the animal and stimulates opioid production in the brainstem is allopregnanolone, a neurosteroid metabolite of progesterone. The supporting evidence for these mechanisms is discussed.
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Affiliation(s)
- Paula J Brunton
- Laboratory of Neuroendocrinology, Centre for Integrative Physiology, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK
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Aguilar-Valles A, Poole S, Mistry Y, Williams S, Luheshi GN. Attenuated fever in rats during late pregnancy is linked to suppressed interleukin-6 production after localized inflammation with turpentine. J Physiol 2007; 583:391-403. [PMID: 17556393 PMCID: PMC2277244 DOI: 10.1113/jphysiol.2007.132829] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
An attenuated fever response to pathogens during late pregnancy is a phenomenon that has been described in several mammalian species, and although mechanisms are not completely understood, decreased prostaglandin E2 (PGE2) synthesis has been implicated. Upstream of PGE2, there is evidence to suggest that anti-inflammatory cytokines such as interleukin-1 receptor antagonist (IL-1ra) could play a significant role. In the present study we addressed the role of pro-inflammatory cytokines during late pregnancy, specifically interleukin-6 (IL-6), an important circulating mediator in fever. Turpentine oil (TURP), a very potent pyrogen and activator of IL-6, was injected into the hind-limb muscle of rats at the 18th day of pregnancy (GD 18) or in non-pregnant (NP) age-matched female controls. As expected, TURP injection induced a highly significant fever in the NP animals, which peaked 11 h post-injection and lasted for over 24 h. This was accompanied by a significant rise in circulating IL-6 levels, which correlated with changes in PGE2 synthesizing enzymes expression in the hypothalamus. In complete contrast, TURP-induced fever was totally absent in GD 18 animals whose body temperature did not deviate from basal values. The lack of response was additionally reflected by the absence of change in IL-6 concentration and by the significant attenuation of PGE2 synthesizing enzymes expression, which correlated with the suppressed expression of SOCS3, a hypothalamic marker of IL-6 activity. Contrary to the changes in circulating IL-6 levels at GD 18, IL-1ra was induced to levels comparable to those of NP females, suggesting that the influence of this anti-inflammatory cytokine on the fever response to TURP is at best minimal. These data further confirm the importance of IL-6 in fever generation and provide evidence that it may be a key component of the attenuated fever response in late pregnancy.
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Affiliation(s)
- Argel Aguilar-Valles
- Douglas Hospital Research Centre, Department of Psychiatry, McGill University, 6875 LaSalle Boulevard, Verdun, Quebec, Canada H4H 1R3
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Begg DP, Kent S, McKinley MJ, Mathai ML. Suppression of endotoxin-induced fever in near-term pregnant rats is mediated by brain nitric oxide. Am J Physiol Regul Integr Comp Physiol 2007; 292:R2174-8. [PMID: 17332165 DOI: 10.1152/ajpregu.00032.2007] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Over the last three decades, experiments in several mammalian species have shown that the febrile response to bacterial endotoxin is attenuated late in pregnancy. More recent evidence has established that the expression of nitric oxide synthase (NOS) enzymes is increased in the brain late in pregnancy. The current study investigated the possible role of brain nitric oxide in mediating the phenomenon of fever suppression. Core body temperature (Tb) of near-term pregnant rats ( day 19 and 20) was measured following inhibition of brain NOS and intraperitoneal injection of LPS (50 μg/kg); they were compared with both day 15 pregnant and virgin animals. Intracerebroventricular injection with an inhibitor of NOS, NG-monomethyl-l-arginine citrate (l-NMMA; 280 μg), in near-term pregnant rats restored the febrile response to LPS. As expected, near-term dams that received intracerebroventricular vehicle + IP LPS did not increase Tb, in contrast to the 1.0 ± 0.2°C rise in Tb in dams treated with ICV l-NMMA + IP LPS ( P < 0.01). In virgin females and day 15 pregnant controls receiving this treatment, the increases in Tb were 1.5 ± 0.3°C and 1.6 ± 0.4°C, respectively. Thus, blockade of brain NOS restored the febrile response to LPS in near-term dams; at 5 h postinjection, Tb was 60–70% of that observed in virgins and day 15 pregnant animals. Intracerebroventricular l-NMMA alone did not induce a significant change in Tb in any group. These results suggest that the mechanism underlying the suppression of the febrile response in near-term pregnancy is mediated by nitric oxide signaling in the brain.
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Affiliation(s)
- Denovan P Begg
- School of Psychological Science, La Trobe University, Bundoora, Victoria, 3086 Australia.
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Ashdown H, Poole S, Boksa P, Luheshi GN. Interleukin-1 receptor antagonist as a modulator of gender differences in the febrile response to lipopolysaccharide in rats. Am J Physiol Regul Integr Comp Physiol 2007; 292:R1667-74. [PMID: 17138728 DOI: 10.1152/ajpregu.00274.2006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Febrile responses to bacterial pathogens are attenuated near term of pregnancy in several mammalian species. It is unknown, however, whether this reflects a fundamental physiological adaptation of female rats or whether it is specific to pregnancy. The aims of this study therefore were 1) to determine whether febrile responses to the bacterial endotoxin lipopolysaccharide (LPS) are attenuated in female vs. male rats and, if so, to identify possible mechanisms involved in modulating this and 2) to assess whether plasma concentrations of the anti-inflammatory cytokine, interleukin-1 receptor antagonist (IL-1ra), an important regulator of fever, are dependent on the physiological state of the female and could therefore be involved in modulating febrile responses. We found febrile responses were attenuated in cycling female vs. male rats and also in near-term pregnant dams vs. cycling females after intraperitoneal injection of LPS (0.05 mg/kg). Plasma levels of IL-1ra were significantly greater in female rats after injection of LPS, particularly during pregnancy, than in males. This was accompanied by attenuated levels of hypothalamic IL-1β and cyclooxygenase-2 mRNA, two key mediators of the febrile response, in female rats. Furthermore, increasing plasma levels of IL-1ra in male rats by intraperitoneal administration of the recombinant antagonist attenuated hypothalamic mRNA levels of these mediators after LPS. These data suggest that there is a fundamental difference in febrile response to LPS between the genders that is likely regulated by IL-1ra. This may be an important mechanism that protects the developing fetus from potentially deleterious consequences of maternal fever during pregnancy.
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Affiliation(s)
- H Ashdown
- McGill University, Department of Psychiatry, Douglas Hospital Research Centre, 6875 LaSalle Boulevard, Montreal, Quebec, Canada H4H 1R3
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Mouihate A, Horn TF, Pittman QJ. Oxyresveratrol dampens neuroimmune responses in vivo: a selective effect on TNF-α. Am J Physiol Regul Integr Comp Physiol 2006; 291:R1215-21. [PMID: 16809485 DOI: 10.1152/ajpregu.00250.2006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Consumption of nutrients rich in hydroxystilbenes has been promoted because of their health benefits, including dampening of inflammatory responses. However, few studies have examined their effects in vivo. Here, we show that the hydroxystilbene oxyresveratrol (trans-2,3′,4,5′-tetrahydroxystilbene: o-RES) blocked hypothermia but caused no significant effect on the febrile response to the immune stimulus, bacterial LPS in rats. This was associated with a reduction in the LPS-induced plasma cytokine, tumor necrosis factor (TNF)-α, but not IL-6. Both IL-6-stimulated STAT-3 and LPS-induced cycoloxygenase-2 expression in the hypothalamus were not affected by o-RES. These data strongly suggest that the o-RES-induced dampening of neuroimmune responses is largely due to its inhibitory effect on TNF-α production. In contrast to in vitro experiments, o-RES has no direct effect on NF-κB signaling pathway in vivo. The specific inhibitory effect of o-RES on TNF-α opens new avenues for the clinical use of o-RES in pathological conditions where excessive production of TNF-α is deleterious.
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Affiliation(s)
- A Mouihate
- Hotchkiss Brain Institute, Dept. of Physiology and Biophysics, Faculty of Medicine, Univ. of Calgary, 3330 Hospital Dr., NW, Calgary, Alberta T2N 4N1, Canada.
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Spencer SJ, Martin S, Mouihate A, Pittman QJ. Early-life immune challenge: defining a critical window for effects on adult responses to immune challenge. Neuropsychopharmacology 2006; 31:1910-8. [PMID: 16395304 DOI: 10.1038/sj.npp.1301004] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Many aspects of mammalian physiology are functionally immature at birth and continue to develop throughout at least the first few weeks of life. Animals are therefore vulnerable during this time to environmental influences such as stress and challenges to the immune system that may permanently affect adult function. The adult immune system is uniquely sensitive to immune challenges encountered during the neonatal period, but it is unknown where the critical window for this programming lies. We subjected male Sprague-Dawley rats at postnatal day (P)7, P14, P21, and P28 to either a saline or lipopolysaccharide (LPS) injection and examined them in adulthood for differences in responses to a further LPS injection. Adult febrile and cyclooxygenase-2 responses to LPS were attenuated in rats given LPS at P14 and P21, but not in those treated at P7 or P28, while P7-LPS rats displayed lower adult body weights than those treated at other times. P28-LPS rats also tended to display enhanced anxiety in the elevated plus maze. In further experiments, we examined maternal-pup interactions, looking at the mothers' preference in two pup-retrieval tasks, and found no differences in maternal attention to LPS-treated pups. We therefore demonstrate a 'critical window' for the effects of a neonatal immune challenge on adult febrile responses to inflammation and suggest that there are other critical time points during development for the programming of adult physiology. We also show that the neonatal LPS effects on the adult immune system are not likely due to overt differences in maternal attention.
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Affiliation(s)
- Sarah J Spencer
- Department of Physiology and Biophysics, Faculty of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
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Wang YF, Hatton GI. Mechanisms Underlying Oxytocin-Induced Excitation of Supraoptic Neurons: Prostaglandin Mediation of Actin Polymerization. J Neurophysiol 2006; 95:3933-47. [PMID: 16554501 DOI: 10.1152/jn.01267.2005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In nonneuronal tissues, activation of oxytocin receptors (OTRs), like other Gαq/11 type G-protein-coupled receptors (Gαq/11/GPCRs), increase prostaglandin (PG) expression. This is not known for the OTRs expressed by central OT neurons. We examined mechanisms underlying OT's effects on supraoptic nucleus (SON) OT and vasopressin (VP) neurons in hypothalamic slices from lactating rats. OT application (10 pM, 10 min) significantly increased firing rates of OT and VP neurons, both of which expressed OTRs. Indomethacin, an inhibitor of PG synthetases, blocked these increases. OTR (but not a V1 receptor) antagonist blocked OT effects without blocking the excitatory effect of PGE2. Tetanus toxin blocked OT effects on fast synaptic inputs and firing activity of SON neurons but not OT-evoked depolarization, suggesting involvement of both pre- and postsynaptic neurons. Indomethacin also blocked the excitatory effects of phenylephrine, another Gαq/11/GPCR activating agent but not those of PGE2, a non-Gαq/11/GPCR activating agent in the SON. OT or phenylephrine, but not glutamate or KCl, enhanced cyclooxygenase 2 expression at cytosolic loci in SON neurons and nearby astrocytes, as revealed by immunocytochemistry. This OT effect was not blocked by TTX. Western blot analyses showed that OT significantly increased cyclooxygenase 2 but not actin expression. OT promoted the formation of filamentous actin (F-actin) networks at membrane subcortical areas of both OT and VP neurons. Indomethacin blocked enhancement of F-actin networks by OT but not by PGE2. These results indicate that PGs serve as a common mediator of Gαq/11/GPCR-activating agents in neuronal function.
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Affiliation(s)
- Yu-Feng Wang
- Department of Cell Biology and Neuroscience, University of California, Riverside, California 92521, USA.
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Russell JA, Brunton PJ. Neuroactive steroids attenuate oxytocin stress responses in late pregnancy. Neuroscience 2006; 138:879-89. [PMID: 16310312 DOI: 10.1016/j.neuroscience.2005.09.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2005] [Revised: 08/03/2005] [Accepted: 09/08/2005] [Indexed: 01/27/2023]
Abstract
In late pregnant rats neuroendocrine stress responses, expressed as increased oxytocin secretion and activation of the hypothalamo-pituitary-adrenal axis, are attenuated. These adaptations preserve the oxytocin store for parturition and prevent pre-term birth, and protect the fetuses from adverse programming by exposure to excess glucocorticoid. Mechanisms of adaptations for oxytocin neurones are reviewed, using challenge with systemic interleukin-1beta, simulating activation of immune signaling by infection, as a stressor of special relevance in pregnancy. In virgin rats, systemic interleukin-1beta stimulates the firing of oxytocin neurones, and hence oxytocin secretion, but interleukin-1beta has no effects in late pregnant rats. This lack of response is reversed by naloxone treatment just before interleukin-1beta administration, indicating endogenous opioid suppression of oxytocin responses in late pregnancy. This opioid presynaptically inhibits noradrenergic terminals impinging on oxytocin neurones. Finasteride pretreatment, inhibiting progesterone conversion to allopregnanolone, a positive GABA(A) receptor allosteric modifier, also restores an oxytocin response to interleukin-1beta. This finasteride effect is reversed by allopregnanolone treatment. In virgin rats allopregnanolone attenuates the oxytocin response to interleukin-1beta, which is exaggerated by naloxone. The effects of naloxone and finasteride in late pregnant rats in restoring an oxytocin response to interleukin-1beta are not additive. Accordingly, allopregnanolone may both enhance GABA inhibition of oxytocin neurone responses to interleukin-1beta, and induce opioid suppression of noradrenaline release onto oxytocin neurones.
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Affiliation(s)
- J A Russell
- Laboratory of Neuroendocrinology, Centre for Integrative Physiology, School of Biomedical Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Hugh Robson Building, UK.
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Abstract
Pregnant rats in late gestation show a reduced fever response after stimulation with lipopolysaccharide (LPS). This can result from either an increased action of endogenous antipyretics or a reduction in the production or action of endogenous pyrogens. Nonpregnant rats given LPS release interleukin (IL)-6, which causes nuclear translocation of the signal transducer and activator of transcription 3 (STAT3) in the vascular organ of the lamina terminalis (OVLT), followed by a significant increase in core body temperature. The present study investigated whether the reduced fever response in near-term pregnant rats is associated with a reduced nuclear STAT3 response. Rats at gestation day 15 (G15), gestation day 21 (G21, near term) and at lactation day 5 (L5) were injected with LPS (50 microg/kg, i.p.) or vehicle. Only near-term pregnant rats responded with an attenuated body temperature during the fever response. Immunohistological analysis indicated no significant difference in nuclear STAT3 in the OVLT of the different animal groups 2 h after LPS. Measurement of total and phosphorylated STAT3 protein in the OVLT with semiquantitative western blot revealed no significant differences of this protein among these immune challenged animal groups. IL-6 concentrations were also similar at G15, G21 and L5 2 h after injection of LPS. These results lead to the conclusion that the attenuation of the fever response at near-term pregnancy is not associated with a reduced amount of nuclear STAT3 in the OVLT, indicating a maintained IL-6-STAT3 signalling pathway in the OVLT.
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Affiliation(s)
- E-M Harré
- Hotchkiss Brain Institute, Department of Physiology and Biophysics, Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada.
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Mouihate A, Ellis S, Harré EM, Pittman QJ. Fever suppression in near-term pregnant rats is dissociated from LPS-activated signaling pathways. Am J Physiol Regul Integr Comp Physiol 2005; 289:R1265-72. [PMID: 16037126 DOI: 10.1152/ajpregu.00342.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Near-term pregnant rats show a suppressed fever response to LPS that is associated with reduced induction of cyclooxygenase (COX)-2 in the hypothalamus. The objective of this study is to explore whether the LPS-activated signaling pathways in the fever-controlling region of the hypothalamus are specifically altered at near term. Three rat groups consisting of 15-day pregnant rats, near-term 21- to 22-day pregnant rats, and day 5 lactating rats were injected with a febrile dose of LPS (50 μg/kg ip). The hypothalamic preoptic area and the organum vasculosum of the lamina terminalis (OVLT) were collected 2 h after LPS injection. The activation of three transcription modulators, nuclear factor-κB (NF-κB), extracellular signal-regulated kinase 1/2 (ERK1/2), and signal transducer and activator of transcription 5 (STAT5), was assessed using semiquantitative Western blot analysis. LPS activated the NF-κB pathway in all rat groups, and this response was not altered at near term. ERK1/2 and STAT5 were constitutively activated during all reproductive stages, and their levels were not significantly affected by LPS injection. Plasma levels of the proinflammatory cytokines (IL-1β, IL-6, TNF-α, and IFN-γ), anti-inflammatory cytokines (IL-4, IL-10, and IL-1 receptor antagonist), and corticosterone were unaffected during the three reproductive stages after LPS challenge. We observed a sharp decrease in the expression of a prostaglandin-producing enzyme called lipocalin-prostaglandin D2 synthase in near-term pregnant and lactating rats. Thus fever suppression at near term is not due to an alteration in either LPS-activated intracellular signaling pathways or LPS-induced pro- and anti-inflammatory cytokine production.
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Affiliation(s)
- A Mouihate
- Hotchkiss Brain Institute, Dept. of Physiology and Biophysics, Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada.
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Rummel C, Barth SW, Voss T, Korte S, Gerstberger R, Hübschle T, Roth J. Localized vs. systemic inflammation in guinea pigs: a role for prostaglandins at distinct points of the fever induction pathways? Am J Physiol Regul Integr Comp Physiol 2005; 289:R340-R347. [PMID: 15831768 DOI: 10.1152/ajpregu.00104.2005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In guinea pigs, dose-dependent febrile responses were induced by injection of a high (100 μg/kg) or a low (10 μg/kg) dose of bacterial lipopolysaccharide (LPS) into artificial subcutaneously implanted Teflon chambers. Both LPS doses further induced a pronounced formation of prostaglandin E2 (PGE2) at the site of localized subcutaneous inflammation. Administration of diclofenac, a nonselective cyclooxygenase (COX) inhibitor, at different doses (5, 50, 500, or 5,000 μg/kg) attenuated or abrogated LPS-induced fever and inhibited LPS-induced local PGE2 formation (5 or 500 μg/kg diclofenac). Even the lowest dose of diclofenac (5 μg/kg) attenuated fever in response to 10 μg/kg LPS, but only when administered directly into the subcutaneous chamber, and not into the site contralateral to the chamber. This observation indicated that a localized formation of PGE2 at the site of inflammation mediated a portion of the febrile response, which was induced by injection of 10 μg/kg LPS into the subcutaneous chamber. Further support for this hypothesis derived from the observation that we failed to detect elevated amounts of COX-2 mRNA in the brain of guinea pigs injected subcutaneously with 10 μg/kg LPS, whereas subcutaneous injections of 100 μg/kg LPS, as well as systemic injections of LPS (intra-arterial or intraperitoneal routes), readily caused expression of the COX-2 gene in the guinea pig brain, as demonstrated by in situ hybridization. Therefore, fever in response to subcutaneous injection of 10 μg/kg LPS may, in part, have been evoked by a neural, rather than a humoral, pathway from the local site of inflammation to the brain.
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Affiliation(s)
- Christoph Rummel
- Institut für Veterinär-Physiologie, Justus-Liebig-Universität Giessen, Frankfurter Strasse 100, 35392 Giessen, Germany
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Brunton PJ, Meddle SL, Ma S, Ochedalski T, Douglas AJ, Russell JA. Endogenous opioids and attenuated hypothalamic-pituitary-adrenal axis responses to immune challenge in pregnant rats. J Neurosci 2005; 25:5117-26. [PMID: 15917452 PMCID: PMC6724825 DOI: 10.1523/jneurosci.0866-05.2005] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2004] [Revised: 04/11/2005] [Accepted: 04/14/2005] [Indexed: 12/29/2022] Open
Abstract
In late pregnant rats, the hypothalamic-pituitary-adrenal (HPA) axis is hyporesponsive to psychogenic stressors. Here, we investigated attenuated HPA responses to an immune challenge and a role for endogenous opioids. ACTH and corticosterone were assayed in blood samples from virgin and 21 d pregnant rats before and after endotoxin [lipopolysaccharide (LPS); 1 microg/kg, i.v.], interleukin-1beta (IL-1beta; 500 ng/kg, i.v.), or vehicle. In virgins, plasma ACTH concentrations increased 1 h after LPS and 15 min after IL-1beta, as did corticosterone, with no responses in pregnant rats. In situ hybridization revealed increased corticotrophin releasing hormone (CRH) mRNA expression in the dorsomedial parvocellular paraventricular nucleus (pPVN) and increased anterior pituitary pro-opiomelanocortin mRNA expression 4 h after IL-1beta in virgins; these responses were absent in pregnant rats. In contrast, immunocytochemistry showed that Fos expression was similarly increased in the nucleus tractus solitarius (NTS) A2 region in virgin and pregnant rats 90 min and 4 h after IL-1beta. Naloxone pretreatment (5 mg/kg, i.v.) restored ACTH and pPVN CRH mRNA responses after IL-1beta in pregnant rats but reduced the CRH mRNA response in virgins without affecting ACTH. Proenkephalin-A and mu-opioid receptor mRNA expression in the NTS was significantly increased in the pregnant rats, indicating upregulated brainstem opioid mechanisms. IL-1beta increased noradrenaline release in the PVN of virgin, but not pregnant, rats. However, naloxone infused directly into the PVN increased noradrenaline release after IL-1beta in pregnant rats. Thus, the HPA axis responses to immune signals are suppressed in pregnancy at the level of pPVN CRH neurons through an opioid mechanism, possibly acting by preterminal autoinhibition of NTS projections to the pPVN.
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Affiliation(s)
- Paula J Brunton
- Laboratory of Neuroendocrinology, Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom.
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Boissé L, Mouihate A, Ellis S, Pittman QJ. Long-term alterations in neuroimmune responses after neonatal exposure to lipopolysaccharide. J Neurosci 2005; 24:4928-34. [PMID: 15163684 PMCID: PMC6729381 DOI: 10.1523/jneurosci.1077-04.2004] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Fever is an integral part of the host's defense to infection that is orchestrated by the brain. A reduced febrile response is associated with reduced survival. Consequently, we have asked if early life immune exposure will alter febrile and neurochemical responses to immune stress in adulthood. Fourteen-day-old neonatal male rats were given Escherichia coli lipopolysaccharide (LPS) that caused either fever or hypothermia depending on ambient temperature. Control rats were given pyrogen-free saline. Regardless of the presence of neonatal fever, adult animals that had been neonatally exposed to LPS displayed attenuated fevers in response to intraperitoneal LPS but unaltered responses to intraperitoneal interleukin 1beta or intracerebroventricular prostaglandin E(2). The characteristic reduction in activity that accompanies fever was unaltered, however, as a function of neonatal LPS exposure. Treatment of neonates with an antigenically dissimilar LPS (Salmonella enteritidis) was equally effective in reducing adult responses to E. coli LPS, indicating an alteration in the innate immune response. In adults treated as neonates with LPS, basal levels of hypothalamic cyclooxygenase 2 (COX-2), determined by semiquantitative Western blot analysis, were significantly elevated compared with controls. In addition, whereas adult controls responded to LPS with the expected induction of COX-2, adults pretreated neonatally with LPS responded to LPS with a reduction in COX-2. Thus, neonatal LPS can alter CNS-mediated inflammatory responses in adult rats.
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Affiliation(s)
- Lysa Boissé
- Calgary Brain Institute, Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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Mathai ML, Arnold I, Febbraio MA, McKinley MJ. Central blockade of nitric oxide synthesis induces hyperthermia that is prevented by indomethacin in rats. J Therm Biol 2004. [DOI: 10.1016/j.jtherbio.2004.08.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Mouihate A, Boissé L, Pittman QJ. A novel antipyretic action of 15-deoxy-Delta12,14-prostaglandin J2 in the rat brain. J Neurosci 2004; 24:1312-8. [PMID: 14960602 PMCID: PMC6730345 DOI: 10.1523/jneurosci.3145-03.2004] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Fever is an important part of the host defense response, yet fever can be detrimental if it is uncontrolled. We provide the first evidence that 15-deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2), an endogenous ligand for peroxisome proliferator-activated receptor gamma (PPARgamma), can attenuate the febrile response to lipopolysaccharide (LPS) in rats via an action on the brain. Furthermore, we show that PPARgamma is expressed in the hypothalamus, an important locus in the brain for fever generation. In addition, 15d-PGJ2 and its synthesizing enzyme (PGD2 synthase) were present in rat cerebrospinal fluid, and their levels were enhanced in response to systemic injection of LPS. The antipyretic effect of 15d-PGJ2 was associated with reduction in LPS-stimulated cyclooxygenase-2 expression in the hypothalamus but not in p44/p42 mitogen-activated protein kinase phosphorylation or in the expression of the PPARgamma. Thus it is likely that there is a parallel induction of an endogenous prostanoid pathway in the brain capable of limiting deleterious actions of the proinflammatory prostaglandin E2-dependent pathway.
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Affiliation(s)
- Abdeslam Mouihate
- Neuroscience Research Group, Department of Physiology and Biophysics, Faculty of Medicine, University of Calgary, Alberta, T2N 4N1 Canada.
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Boksa P, Luheshi GN. On the use of animal modeling to study maternal infection during pregnancy and prenatal cytokine exposure as risk factors for schizophrenia. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/j.cnr.2003.10.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Affiliation(s)
- Holger Scholz
- Johannes-Müller-Institut für Physiologie, Humboldt-Universität, Charité, Tucholskystrasse 2, 10117 Berlin, Germany.
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Romanovsky AA, Petersen SR. The spleen: another mystery about its function. Am J Physiol Regul Integr Comp Physiol 2003; 284:R1378-9. [PMID: 12736172 DOI: 10.1152/ajpregu.00135.2003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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40
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Affiliation(s)
- Holger Scholz
- Johannes-Müller-Institut für Physiologie, Medizinische Fakultät Charité, Humboldt-Universität Berlin, 10117 Berlin, Germany.
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Ivanov AI, Romanovsky AA. Near-term suppression of fever: inhibited synthesis or accelerated catabolism of prostaglandin E2? Am J Physiol Regul Integr Comp Physiol 2003; 284:R860-1; author reply R861-5. [PMID: 12571081 DOI: 10.1152/ajpregu.00618.2002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Imai-Matsumura K, Matsumura K, Terao A, Watanabe Y. Attenuated fever in pregnant rats is associated with blunted syntheses of brain cyclooxygenase-2 and PGE2. Am J Physiol Regul Integr Comp Physiol 2002; 283:R1346-53. [PMID: 12388434 DOI: 10.1152/ajpregu.00396.2002] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Attenuation of fever occurs in pregnant animals. This study examined a hypothesis that brain production of PGE(2), the final mediator of fever, is suppressed in pregnant animals. Near-term pregnant rats and age-matched nonpregnant female rats were injected with lipopolysaccharide (100 microg/kg) intraperitoneally. Four hours later, colonic temperature was measured, their cerebrospinal fluid (CSF) was sampled for PGE(2) assay, and their brains were processed for immunohistochemistry of cyclooxygenase-2, an enzyme involved in PGE(2) biosynthesis. In the pregnant rats, lipopolysaccharide injection resulted in significantly smaller elevations in both colonic temperature and CSF-PGE(2) level than in nonpregnant rats. In the pregnant rats, lipopolysaccharide-induced cyclooxygenase-2 expression was blunted in terms of the number of positive cells. There was a significant correlation between PGE(2) level in CSF and the number of cyclooxygenase-2-positive endothelial cells. These results suggest that suppressed PGE(2) production in the brain is one cause for the attenuated fever response at near-term pregnancy and that this suppressed PGE(2) production is due to the suppressed induction of cyclooxygenase-2 in brain endothelial cells.
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Affiliation(s)
- Kyoko Imai-Matsumura
- Department of Life and Health Sciences, Hyogo University of Teacher Education, Hyogo 673-1494
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