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Miyata S. Glial functions in the blood-brain communication at the circumventricular organs. Front Neurosci 2022; 16:991779. [PMID: 36278020 PMCID: PMC9583022 DOI: 10.3389/fnins.2022.991779] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
The circumventricular organs (CVOs) are located around the brain ventricles, lack a blood-brain barrier (BBB) and sense blood-derived molecules. This review discusses recent advances in the importance of CVO functions, especially glial cells transferring periphery inflammation signals to the brain. The CVOs show size-limited vascular permeability, allowing the passage of molecules with molecular weight <10,000. This indicates that the lack of an endothelial cell barrier does not mean the free movement of blood-derived molecules into the CVO parenchyma. Astrocytes and tanycytes constitute a dense barrier at the distal CVO subdivision, preventing the free diffusion of blood-derived molecules into neighboring brain regions. Tanycytes in the CVOs mediate communication between cerebrospinal fluid and brain parenchyma via transcytosis. Microglia and macrophages of the CVOs are essential for transmitting peripheral information to other brain regions via toll-like receptor 2 (TLR2). Inhibition of TLR2 signaling or depletion of microglia and macrophages in the brain eliminates TLR2-dependent inflammatory responses. In contrast to TLR2, astrocytes and tanycytes in the CVOs of the brain are crucial for initiating lipopolysaccharide (LPS)-induced inflammatory responses via TLR4. Depletion of microglia and macrophages augments LPS-induced fever and chronic sickness responses. Microglia and macrophages in the CVOs are continuously activated, even under normal physiological conditions, as they exhibit activated morphology and express the M1/M2 marker proteins. Moreover, the microglial proliferation occurs in various regions, such as the hypothalamus, medulla oblongata, and telencephalon, with a marked increase in the CVOs, due to low-dose LPS administration, and after high-dose LPS administration, proliferation is seen in most brain regions, except for the cerebral cortex and hippocampus. A transient increase in the microglial population is beneficial during LPS-induced inflammation for attenuating sickness response. Transient receptor potential receptor vanilloid 1 expressed in astrocytes and tanycytes of the CVOs is responsible for thermoregulation upon exposure to a warm environment less than 37°C. Alternatively, Nax expressed in astrocytes and tanycytes of the CVOs is crucial for maintaining body fluid homeostasis. Thus, recent findings indicate that glial cells in the brain CVOs are essential for initiating neuroinflammatory responses and maintaining body fluid and thermal homeostasis.
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Venkataranganayaka Abhilasha K, Kedihithlu Marathe G. Bacterial lipoproteins in sepsis. Immunobiology 2021; 226:152128. [PMID: 34488139 DOI: 10.1016/j.imbio.2021.152128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 07/09/2021] [Accepted: 08/10/2021] [Indexed: 01/05/2023]
Abstract
Bacterial lipoproteins are membrane proteins derived from both gram-negative and gram-positive bacteria. They seem to have diverse functions not only on bacterial growth, but also play an important role in host's virulence. Bacterial lipoproteins exert their action on host immune cells via TLR2/1 or TLR2/6. Therefore, bacterial lipoproteins also need to be considered while addressing bacterial pathogenicity besides classical bacterial endotoxin like LPS and other microbial associated molecular patterns such as LTA, and peptidoglycans. In this mini-review, we provide an overview of general bacterial lipoprotein biosynthesis and the need to understand the lipoprotein-mediated pathogenicity in diseases like sepsis.
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Affiliation(s)
- Kandahalli Venkataranganayaka Abhilasha
- Department of Studies in Biochemistry, University of Mysore, Manasagangothri, Mysuru 570006, Karnataka, India; Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Gopal Kedihithlu Marathe
- Department of Studies in Biochemistry, University of Mysore, Manasagangothri, Mysuru 570006, Karnataka, India; Department of Studies in Molecular Biology, University of Mysore, Manasagangothri, Mysuru 570006, Karnataka, India.
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3
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Depletion of microglia and macrophages with clodronate liposomes attenuates zymosan-induced Fos expression and hypothermia in the adult mouse. J Neuroimmunol 2020; 344:577244. [DOI: 10.1016/j.jneuroim.2020.577244] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 04/04/2020] [Accepted: 04/14/2020] [Indexed: 12/14/2022]
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4
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Zhao W, Bendickson L, Nilsen-Hamilton M. The Lipocalin2 Gene is Regulated in Mammary Epithelial Cells by NFκB and C/EBP In Response to Mycoplasma. Sci Rep 2020; 10:7641. [PMID: 32376831 PMCID: PMC7203223 DOI: 10.1038/s41598-020-63393-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 03/25/2020] [Indexed: 02/02/2023] Open
Abstract
Lcn2 gene expression increases in response to cell stress signals, particularly in cells involved in the innate immune response. Human Lcn2 (NGAL) is increased in the blood and tissues in response to many stressors including microbial infection and in response to LPS in myeloid and epithelial cells. Here we extend the microbial activators of Lcn2 to mycoplasma and describe studies in which the mechanism of Lcn2 gene regulation by MALP-2 and mycoplasma infection was investigated in mouse mammary epithelial cells. As for the LPS response of myeloid cells, Lcn2 expression in epithelial cells is preceded by increased TNFα, IL-6 and IκBζ expression and selective reduction of IκBζ reduces Lcn2 promoter activity. Lcn2 promoter activation remains elevated well beyond the period of exposure to MALP-2 and is persistently elevated in mycoplasma infected cells. Activation of either the human or the mouse Lcn2 promoter requires both NFκB and C/EBP for activation. Thus, Lcn2 is strongly and enduringly activated by mycoplasma components that stimulate the innate immune response with the same basic regulatory mechanism for the human and mouse genes.
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Affiliation(s)
- Wei Zhao
- Roy J Carver Department of Biochemistry, Biophysics and Molecular Biology and the Interdepartmental Molecular, Cellular and Developmental Biology Program, Iowa State University, Ames, IA, 50011, USA
- Interdepartmental Molecular, Cellular and Developmental Biology Program, Iowa State University, Ames, IA, 50011, USA
- Bayview Physicians Group, Battlefield Medical association, 675 North Battlefield Boulevard, Chesapeake, VA, 23320, USA
| | - Lee Bendickson
- Roy J Carver Department of Biochemistry, Biophysics and Molecular Biology and the Interdepartmental Molecular, Cellular and Developmental Biology Program, Iowa State University, Ames, IA, 50011, USA
| | - Marit Nilsen-Hamilton
- Roy J Carver Department of Biochemistry, Biophysics and Molecular Biology and the Interdepartmental Molecular, Cellular and Developmental Biology Program, Iowa State University, Ames, IA, 50011, USA.
- Interdepartmental Molecular, Cellular and Developmental Biology Program, Iowa State University, Ames, IA, 50011, USA.
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5
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Kornspan JD, Kosower NS, Vaisid T, Katzhandler J, Rottem S. Novel synthetic lipopeptides derived from Mycoplasma hyorhinis upregulate calpastatin in SH-SY5Y neuroblastoma cells and induce a neuroprotective effect against amyloid-β-peptide toxicity. FEMS Microbiol Lett 2020; 367:5824629. [PMID: 32329786 DOI: 10.1093/femsle/fnaa073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 04/22/2020] [Indexed: 11/14/2022] Open
Abstract
Previously, we showed that contamination of SH-SY5Y neuroblastoma cells by Mycoplasma hyorhinis strains NDMh and MCLD leads to increased levels of calpastatin (the endogenous, specific inhibitor of the Ca2+-dependent protease calpain), resulting in inhibition of calpain activation. We have found that the increased calpastatin level is promoted by the lipoprotein fraction (MhLpp) of the mycoplasmal membrane. Here, we present MhLpp-based novel synthetic lipopeptides that induce upregulation of calpastatin in SH-SY5Y neuroblastoma cells, leading to protection of the treated cells against Ca2+/amyloid-β-peptide toxicity. These lipopeptides present a new class of promising agents against calpain-induced cell toxicity.
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Affiliation(s)
- Jonathan D Kornspan
- Department of Microbiology and Molecular Genetics, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Nechama S Kosower
- Department of Human Molecular Genetics & Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Tali Vaisid
- Department of Human Molecular Genetics & Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | | | - Shlomo Rottem
- Department of Microbiology and Molecular Genetics, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
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6
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Murayama S, Kurganov E, Miyata S. Activation of microglia and macrophages in the circumventricular organs of the mouse brain during TLR2-induced fever and sickness responses. J Neuroimmunol 2019; 334:576973. [PMID: 31170673 DOI: 10.1016/j.jneuroim.2019.576973] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 05/26/2019] [Accepted: 05/27/2019] [Indexed: 01/28/2023]
Abstract
Toll-like receptor 2 (TLR2) recognizes cell wall components from Gram-positive bacteria. Until now, however, little has been known about the significance of brain TLR2 in controlling inflammation and thermoregulatory responses during systemic Gram-positive bacterial infection. In the present study, the TLR2 immunoreactivity was seen to be prominent in the microglia/macrophages of the circumventricular organs (CVOs) of the mouse brain. The intraperitoneal injection of Pam3CSK4, a TLR2 agonist, induced nuclear factor-κ B activation in the microglia/macrophages of the CVOs. The injection of Pam3CSK4 also produced the expression of Fos at astrocytes and neurons in the CVOs and the regions neighboring the CVOs. The Pam3CSK4 injection induced fever and sickness responses. Pretreatment with lipopolysaccharide, a TLR4 agonist, augmented the Pam3CSK4-induced fever together with the increased TLR2 immunoreactivity. These results indicate that the TLR2 in microglia/macrophages of the CVOs are possibly associated with initiating and transmitting inflammatory responses in the brain.
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Affiliation(s)
- Saki Murayama
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Erkin Kurganov
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Seiji Miyata
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
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7
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Nguyen MT, Uebele J, Kumari N, Nakayama H, Peter L, Ticha O, Woischnig AK, Schmaler M, Khanna N, Dohmae N, Lee BL, Bekeredjian-Ding I, Götz F. Lipid moieties on lipoproteins of commensal and non-commensal staphylococci induce differential immune responses. Nat Commun 2017; 8:2246. [PMID: 29269769 PMCID: PMC5740139 DOI: 10.1038/s41467-017-02234-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 11/15/2017] [Indexed: 02/08/2023] Open
Abstract
Lipoproteins (Lpp) of Gram-positive bacteria are major players in alerting our immune system. Here, we show that the TLR2 response induced by commensal species Staphylococcus aureus and Staphylococcus epidermidis is almost ten times lower than that induced by noncommensal Staphylococcus carnosus, and this is at least partially due to their different modifications of the Lpp lipid moieties. The N terminus of the lipid moiety is acylated with a long-chain fatty acid (C17) in S. aureus and S. epidermidis, while it is acylated with a short-chain fatty acid (C2) in S. carnosus. The long-chain N-acylated Lpp, recognized by TLR2-TLR1 receptors, silences innate and adaptive immune responses, while the short-chain N-acetylated Lpp, recognized by TLR2-TLR6 receptors, boosts it.
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Affiliation(s)
- Minh-Thu Nguyen
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, 72076, Germany.,School of Biological and Food Technology, Hanoi University of Science and Technology, Hanoi, 1000, Vietnam
| | - Julia Uebele
- Paul-Ehrlich-Institute, Federal Regulatory Agency for Vaccines and Biomedicines, Langen, 63225, Germany
| | - Nimerta Kumari
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, 72076, Germany
| | - Hiroshi Nakayama
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Saitama, 351-0198, Japan
| | - Lena Peter
- Paul-Ehrlich-Institute, Federal Regulatory Agency for Vaccines and Biomedicines, Langen, 63225, Germany
| | - Olga Ticha
- Paul-Ehrlich-Institute, Federal Regulatory Agency for Vaccines and Biomedicines, Langen, 63225, Germany
| | - Anne-Kathrin Woischnig
- Laboratory of Infection Biology, Department of Biomedicine, University Hospital Basel, Basel, CH-4031, Switzerland
| | - Mathias Schmaler
- Laboratory of Infection Biology, Department of Biomedicine, University Hospital Basel, Basel, CH-4031, Switzerland
| | - Nina Khanna
- Laboratory of Infection Biology, Department of Biomedicine, University Hospital Basel, Basel, CH-4031, Switzerland
| | - Naoshi Dohmae
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Saitama, 351-0198, Japan
| | - Bok Luel Lee
- National Research Laboratory of Defense Proteins, College of Pharmacy, Pusan National University, Pusan, 609-735, South Korea
| | - Isabelle Bekeredjian-Ding
- Paul-Ehrlich-Institute, Federal Regulatory Agency for Vaccines and Biomedicines, Langen, 63225, Germany
| | - Friedrich Götz
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, 72076, Germany.
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8
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Inflammatory transcription factors as activation markers and functional readouts in immune-to-brain communication. Brain Behav Immun 2016; 54:1-14. [PMID: 26348582 DOI: 10.1016/j.bbi.2015.09.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 08/31/2015] [Accepted: 09/04/2015] [Indexed: 02/06/2023] Open
Abstract
Immune-to-brain communication pathways involve humoral mediators, including cytokines, central modulation by neuronal afferents and immune cell trafficking to the brain. During systemic inflammation these pathways contribute to mediating brain-controlled sickness symptoms including fever. Experimentally, activation of these signaling pathways can be mimicked and studied when injecting animals with pathogen associated molecular patterns (PAMPS). One central component of the brain inflammatory response, which leads, for example, to fever induction, is transcriptional activation of brain cells via cytokines and PAMPS. We and others have studied the spatiotemporal activation and the physiological significance of transcription factors for the induction of inflammation within the brain and the manifestation of fever. Evidence has revealed a role of nuclear factor (NF)κB in the initiation, signal transducer and activator of transcription (STAT)3 in the maintenance and NF-interleukin (IL)6 in the maintenance or even termination of brain-inflammation and fever. Moreover, psychological stressors, such as exposure to a novel environment, leads to increased body core temperature and genomic NF-IL6-activation, suggesting a potential use of NF-IL6-immunohistochemistry as a multimodal brain cell activation marker and a role for NF-IL6 for differential brain activity. In addition, the nutritional status, as reflected by circulating levels of the cytokine-like hormone leptin, influence immune-to-brain communication and age-dependent changes in LPS-induced fever. Overall, transcription factors remain therapeutically important targets for the treatment of brain-inflammation and fever induction during infectious/non-infectious inflammatory and psychological stress. However, the exact physiological role and significance of these transcription factors requires to be further investigated.
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9
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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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10
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Damm J, Wiegand F, Harden LM, Wenisch S, Gerstberger R, Rummel C, Roth J. Intraperitoneal and subcutaneous injections of the TLR9 agonist ODN 1668 in rats: brain inflammatory responses are related to peripheral IL-6 rather than interferons. J Neuroimmunol 2014; 277:105-17. [PMID: 25465287 DOI: 10.1016/j.jneuroim.2014.10.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 10/20/2014] [Accepted: 10/21/2014] [Indexed: 12/30/2022]
Abstract
Subcutaneous or intraperitoneal administration of Toll-like receptor (TLR)-9 agonist, ODN 1668 caused moderate fever and anorexia. In comparison to stimulation of other intracellular TLRs, activation of TLR9 did not result in pronounced peripheral induction of interferons, but rather induced interleukin-6. Expression of cytokines (TNFα, IL-1β) and inducible forms of enzymes for prostaglandin E2 synthesis occurred in the brain, in conjunction with a moderate activation of the transcription factors STAT3 and NF-IL6 in brain endothelial cells. The lack of a septic-like state in ODN 1668-treated rats reinforces the therapeutic value of this drug.
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Affiliation(s)
- J Damm
- Institute of Veterinary-Physiology and -Biochemistry, Justus-Liebig-University of Giessen, Frankfurter Strasse 100, D-35392 Giessen, Germany
| | - F Wiegand
- Institute of Veterinary-Physiology and -Biochemistry, Justus-Liebig-University of Giessen, Frankfurter Strasse 100, D-35392 Giessen, Germany
| | - L M Harden
- Institute of Veterinary-Physiology and -Biochemistry, Justus-Liebig-University of Giessen, Frankfurter Strasse 100, D-35392 Giessen, Germany; Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg, South Africa
| | - S Wenisch
- Institute of Veterinary-Anatomy, Justus-Liebig-University of Giessen, Frankfurter Strasse 98, D-35392 Giessen, Germany
| | - R Gerstberger
- Institute of Veterinary-Physiology and -Biochemistry, Justus-Liebig-University of Giessen, Frankfurter Strasse 100, D-35392 Giessen, Germany
| | - C Rummel
- Institute of Veterinary-Physiology and -Biochemistry, Justus-Liebig-University of Giessen, Frankfurter Strasse 100, D-35392 Giessen, Germany
| | - J Roth
- Institute of Veterinary-Physiology and -Biochemistry, Justus-Liebig-University of Giessen, Frankfurter Strasse 100, D-35392 Giessen, Germany.
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11
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Zhao J, Chen Y, Xu Y, Pi G. Effect of intrauterine infection on brain development and injury. Int J Dev Neurosci 2013; 31:543-9. [DOI: 10.1016/j.ijdevneu.2013.06.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 06/23/2013] [Accepted: 06/23/2013] [Indexed: 01/01/2023] Open
Affiliation(s)
- Jing Zhao
- Department of NeonatologyAffiliated Hospital of North Sichuan Medical CollegeNanchong637000China
- Department of PediatricsAffiliated Hospital of North Sichuan Medical CollegeNanchong637000China
| | - Yurong Chen
- Department of NeonatologyAffiliated Hospital of North Sichuan Medical CollegeNanchong637000China
- Department of PediatricsAffiliated Hospital of North Sichuan Medical CollegeNanchong637000China
| | - Yuxia Xu
- Department of PediatricsAffiliated Hospital of North Sichuan Medical CollegeNanchong637000China
| | - Guanghuan Pi
- Department of PediatricsAffiliated Hospital of North Sichuan Medical CollegeNanchong637000China
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12
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McCusker RH, Kelley KW. Immune-neural connections: how the immune system's response to infectious agents influences behavior. ACTA ACUST UNITED AC 2013; 216:84-98. [PMID: 23225871 DOI: 10.1242/jeb.073411] [Citation(s) in RCA: 298] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Humans and animals use the classical five senses of sight, sound, touch, smell and taste to monitor their environment. The very survival of feral animals depends on these sensory perception systems, which is a central theme in scholarly research on comparative aspects of anatomy and physiology. But how do all of us sense and respond to an infection? We cannot see, hear, feel, smell or taste bacterial and viral pathogens, but humans and animals alike are fully aware of symptoms of sickness that are caused by these microbes. Pain, fatigue, altered sleep pattern, anorexia and fever are common symptoms in both sick animals and humans. Many of these physiological changes represent adaptive responses that are considered to promote animal survival, and this constellation of events results in sickness behavior. Infectious agents display a variety of pathogen-associated molecular patterns (PAMPs) that are recognized by pattern recognition receptors (PRRs). These PRR are expressed on both the surface [e.g. Toll-like receptor (TLR)-4] and in the cytoplasm [e.g. nucleotide-binding oligomerization domain (Nod)-like receptors] of cells of the innate immune system, primarily macrophages and dendritic cells. These cells initiate and propagate an inflammatory response by stimulating the synthesis and release of a variety of cytokines. Once an infection has occurred in the periphery, both cytokines and bacterial toxins deliver this information to the brain using both humoral and neuronal routes of communication. For example, binding of PRR can lead to activation of the afferent vagus nerve, which communicates neuronal signals via the lower brain stem (nucleus tractus solitarius) to higher brain centers such as the hypothalamus and amygdala. Blood-borne cytokines initiate a cytokine response from vascular endothelial cells that form the blood-brain barrier (BBB). Cytokines can also reach the brain directly by leakage through the BBB via circumventricular organs or by being synthesized within the brain, thus forming a mirror image of the cytokine milieu in the periphery. Although all cells within the brain are capable of initiating cytokine secretion, microglia have an early response to incoming neuronal and humoral stimuli. Inhibition of proinflammatory cytokines that are induced following bacterial infection blocks the appearance of sickness behaviors. Collectively, these data are consistent with the notion that the immune system communicates with the brain to regulate behavior in a way that is consistent with animal survival.
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Affiliation(s)
- Robert H McCusker
- Integrative Immunology and Behavior Program, Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801-3873, USA.
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Rummel C, Gerstberger R, Roth J, Hübschle T. Parthenolide attenuates LPS-induced fever, circulating cytokines and markers of brain inflammation in rats. Cytokine 2011; 56:739-48. [DOI: 10.1016/j.cyto.2011.09.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 09/23/2011] [Accepted: 09/25/2011] [Indexed: 12/20/2022]
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14
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Damm J, Wiegand F, Harden LM, Gerstberger R, Rummel C, Roth J. Fever, sickness behavior, and expression of inflammatory genes in the hypothalamus after systemic and localized subcutaneous stimulation of rats with the Toll-like receptor 7 agonist imiquimod. Neuroscience 2011; 201:166-83. [PMID: 22116053 DOI: 10.1016/j.neuroscience.2011.11.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 11/03/2011] [Accepted: 11/04/2011] [Indexed: 11/19/2022]
Abstract
The Toll-like receptor 7 (TLR7) agonist imiquimod is used for topical treatment of skin cancers. We studied the consequences of injections of imiquimod into a subcutaneous (s.c.) air pouch or of intraperitoneal (i.p.) injections on the manifestation of fever, sickness behavior, and the peripheral and brain-intrinsic induction of a variety of inflammatory molecules. Rats were given imiqimod s.c. or i.p. (1 or 5 mg/kg). Body temperature, motor activity, and food and water intake were recorded by telemetric devices. Peripheral and brain-intrinsic induction of inflammatory mediators was analyzed by real-time polymerase chain reaction (RT-PCR), bioassays, enzyme-linked immunosorbent assays (ELISAs), and immunohistochemistry. Imiquimod is the first TLR-agonist to produce more potent effects with s.c. than i.p. administration. Peripheral induction of interferons (IFNs) and putative circulating pyrogens corresponded to the magnitude of the illness responses. In the brain, an expression of cytokines (TNFα, IL-1β, and IL-6) and inducible forms of enzymes for prostaglandin E2 synthesis (COX-2 and mPGES) occurred, which was accompanied by a moderate activation of the transcription factors NFκB and STAT3, and a strong activation of the transcription factor NF-IL6, in cells of specific areas with an open blood-brain barrier. These inflammatory responses noted within the brain were more marked after s.c. administration, than i.p. administration of imiquimod. At a dose of 5 mg/kg, imiquimod causes rather moderate brain-inflammatory responses, which are related to peripheral IFN-expression and possibly mediated by brain-intrinsic activation of NF-IL6 and induction of a proinflammatory cocktail. The lack of a septic-like state in imiquimod-treated rats reinforces the therapeutic use of this drug.
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Affiliation(s)
- J Damm
- Institut für Veterinär-Physiologie und -Biochemie, Justus-Liebig-Universität Giessen, Frankfurter Strasse 100, D-35392 Giessen, Germany
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15
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Welsch J, Hübschle T, Murgott J, Kirschning C, Rummel C, Gerstberger R, Roth J. Fever induction by systemic stimulation with macrophage-activating lipopeptide-2 depends upon TLR2 but not CD36. Innate Immun 2011; 18:541-59. [DOI: 10.1177/1753425911426892] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
This study was designed to test the responses of TLR2-knockout mice (TLR2-KO) and wild- type mice (C57/BL-6), and of CD36 deficient spontaneously hypertensive rats (SHR) and their genetic controls [Wistar Kyoto (WKY) rats] to systemic stimulations with the TLR2/6 agonist MALP-2 and the TLR4 agonist LPS. Fever and formation of TNF-α and IL-6 induced by intraperitoneal injections of MALP-2 (1000 µg/kg) were completely blunted in TLR2-KO, while LPS (100 µg/kg)-induced responses were not abolished in these animals. In SHR lacking CD36, a reduction of fever was observed in response to MALP-2 (100 µg/kg), but LPS-fever was even more attenuated in SHR when compared with WKY controls. Concentrations of circulating IL-6 tended to be lower in SHR after stimulation with both pyrogens. However, the IL-6-mediated activation of the transcription factor STAT3 in the brain was identical in both strains, indicating that the brain-controlled inflammatory response to MALP-2 (and LPS) is not impaired in the absence of CD36. In addition, stimulation of peritoneal macrophages with LPS and MALP-2 (10 µg/ml) caused the appearance of similar concentrations of bioactive cytokines in the supernatants from cells of both rat strains. These results demonstrate that TLR2 is essential for the manifestation of MALP-2, but not LPS-induced inflammatory responses. A moderate participation of CD36 in MALP-2-induced sickness- and cytokine-responses can not be ruled out but is unlikely as LPS-induced inflammatory responses were also attenuated in SHR.
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Affiliation(s)
- Janina Welsch
- Institut für Veterinär-Physiologie und -Biochemie, Justus-Liebig- Universität Giessen, Giessen, Germany
| | - Thomas Hübschle
- Institut für Veterinär-Physiologie und -Biochemie, Justus-Liebig- Universität Giessen, Giessen, Germany
| | - Jolanta Murgott
- Institut für Veterinär-Physiologie und -Biochemie, Justus-Liebig- Universität Giessen, Giessen, Germany
| | - Carsten Kirschning
- Institut für Medizinische Mikrobiologie, Universitätsklinikum Essen, Germany
| | - Christoph Rummel
- Institut für Veterinär-Physiologie und -Biochemie, Justus-Liebig- Universität Giessen, Giessen, Germany
| | - Rüdiger Gerstberger
- Institut für Veterinär-Physiologie und -Biochemie, Justus-Liebig- Universität Giessen, Giessen, Germany
| | - Joachim Roth
- Institut für Veterinär-Physiologie und -Biochemie, Justus-Liebig- Universität Giessen, Giessen, Germany
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A crucial role for IL-6 in the CNS of rats during fever induced by the injection of live E. coli. Med Microbiol Immunol 2011; 201:47-60. [DOI: 10.1007/s00430-011-0204-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Indexed: 12/20/2022]
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17
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Knorr C, Marks D, Gerstberger R, Mühlradt PF, Roth J, Rummel C. Peripheral and central cyclooxygenase (COX) products may contribute to the manifestation of brain-controlled sickness responses during localized inflammation induced by macrophage-activating lipopeptide-2 (MALP-2). Neurosci Lett 2010; 479:107-11. [DOI: 10.1016/j.neulet.2010.05.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 05/10/2010] [Accepted: 05/11/2010] [Indexed: 11/30/2022]
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18
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Smith PM, Ferguson AV. Circulating signals as critical regulators of autonomic state--central roles for the subfornical organ. Am J Physiol Regul Integr Comp Physiol 2010; 299:R405-15. [PMID: 20463185 DOI: 10.1152/ajpregu.00103.2010] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
To maintain homeostasis autonomic control centers in the hypothalamus and medulla must respond appropriately to both external and internal stimuli. Although protected behind the blood-brain barrier, neurons in these autonomic control centers are known to be influenced by changing levels of important signaling molecules in the systemic circulation (e.g., osmolarity, glucose concentrations, and regulatory peptides). The subfornical organ belongs to a group of specialized central nervous system structures, the circumventricular organs, which are characterized by the lack of the normal blood-brain barrier, such that circulating lipophobic substances may act on neurons within this region and via well-documented efferent neural projections to hypothalamic autonomic control centers, influence autonomic function. This review focuses on the role of the subfornical organ in sensing peripheral signals and transmitting this information to autonomic control centers in the hypothalamus.
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Affiliation(s)
- Pauline M Smith
- Dept. of Physiology, Queen's Univ., Kingston, Ontario, Canada K7L 3N6
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Switalla S, Lauenstein L, Prenzler F, Knothe S, Förster C, Fieguth HG, Pfennig O, Schaumann F, Martin C, Guzman CA, Ebensen T, Müller M, Hohlfeld JM, Krug N, Braun A, Sewald K. Natural innate cytokine response to immunomodulators and adjuvants in human precision-cut lung slices. Toxicol Appl Pharmacol 2010; 246:107-15. [PMID: 20434477 DOI: 10.1016/j.taap.2010.04.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 04/13/2010] [Accepted: 04/14/2010] [Indexed: 11/16/2022]
Abstract
Prediction of lung innate immune responses is critical for developing new drugs. Well-established immune modulators like lipopolysaccharides (LPS) can elicit a wide range of immunological effects. They are involved in acute lung diseases such as infections or chronic airway diseases such as COPD. LPS has a strong adjuvant activity, but its pyrogenicity has precluded therapeutic use. The bacterial lipopeptide MALP-2 and its synthetic derivative BPPcysMPEG are better tolerated. We have compared the effects of LPS and BPPcysMPEG on the innate immune response in human precision-cut lung slices. Cytokine responses were quantified by ELISA, Luminex, and Meso Scale Discovery technology. The initial response to LPS and BPPcysMPEG was marked by coordinated and significant release of the mediators IL-1β, MIP-1β, and IL-10 in viable PCLS. Stimulation of lung tissue with BPPcysMPEG, however, induced a differential response. While LPS upregulated IFN-γ, BPPcysMPEG did not. This traces back to their signaling pathways via TLR4 and TLR2/6. The calculated exposure doses selected for LPS covered ranges occurring in clinical studies with human beings. Correlation of obtained data with data from human BAL fluid after segmental provocation with endotoxin showed highly comparable effects, resulting in a coefficient of correlation >0.9. Furthermore, we were interested in modulating the response to LPS. Using dexamethasone as an immunosuppressive drug for anti-inflammatory therapy, we found a significant reduction of GM-CSF, IL-1β, and IFN-γ. The PCLS-model offers the unique opportunity to test the efficacy and toxicity of biological agents intended for use by inhalation in a complex setting in humans.
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Affiliation(s)
- S Switalla
- Fraunhofer Institute for Toxicology and Experimental Medicine, Division of Immunology, Allergy and Airway Research, Nikolai-Fuchs-Str. 1, D-30625 Hannover, Germany
| | - L Lauenstein
- Fraunhofer Institute for Toxicology and Experimental Medicine, Division of Immunology, Allergy and Airway Research, Nikolai-Fuchs-Str. 1, D-30625 Hannover, Germany
| | - F Prenzler
- Fraunhofer Institute for Toxicology and Experimental Medicine, Division of Immunology, Allergy and Airway Research, Nikolai-Fuchs-Str. 1, D-30625 Hannover, Germany
| | - S Knothe
- Fraunhofer Institute for Toxicology and Experimental Medicine, Division of Immunology, Allergy and Airway Research, Nikolai-Fuchs-Str. 1, D-30625 Hannover, Germany
| | - C Förster
- Klinikum Region Hannover (KRH), Hannover, Germany
| | - H-G Fieguth
- Klinikum Region Hannover (KRH), Hannover, Germany
| | - O Pfennig
- Klinikum Region Hannover (KRH), Hannover, Germany
| | - F Schaumann
- Fraunhofer Institute for Toxicology and Experimental Medicine, Division of Immunology, Allergy and Airway Research, Nikolai-Fuchs-Str. 1, D-30625 Hannover, Germany
| | - C Martin
- Institute of Pharmacology and Toxicology, RWTH Aachen, Wendlingweg 2, 52074 Aachen, Germany
| | - C A Guzman
- Helmholtz Centre for Infection Research, Department of Vaccinology and Applied Microbiology, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - T Ebensen
- Helmholtz Centre for Infection Research, Department of Vaccinology and Applied Microbiology, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - M Müller
- Fraunhofer Institute for Toxicology and Experimental Medicine, Division of Immunology, Allergy and Airway Research, Nikolai-Fuchs-Str. 1, D-30625 Hannover, Germany
| | - J M Hohlfeld
- Fraunhofer Institute for Toxicology and Experimental Medicine, Division of Immunology, Allergy and Airway Research, Nikolai-Fuchs-Str. 1, D-30625 Hannover, Germany
| | - N Krug
- Fraunhofer Institute for Toxicology and Experimental Medicine, Division of Immunology, Allergy and Airway Research, Nikolai-Fuchs-Str. 1, D-30625 Hannover, Germany
| | - A Braun
- Fraunhofer Institute for Toxicology and Experimental Medicine, Division of Immunology, Allergy and Airway Research, Nikolai-Fuchs-Str. 1, D-30625 Hannover, Germany
| | - K Sewald
- Fraunhofer Institute for Toxicology and Experimental Medicine, Division of Immunology, Allergy and Airway Research, Nikolai-Fuchs-Str. 1, D-30625 Hannover, Germany
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Blocking TLR2 activity attenuates pulmonary metastases of tumor. PLoS One 2009; 4:e6520. [PMID: 19654875 PMCID: PMC2716531 DOI: 10.1371/journal.pone.0006520] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Accepted: 07/08/2009] [Indexed: 12/26/2022] Open
Abstract
Background Metastasis is the most pivotal cause of mortality in cancer patients. Immune tolerance plays a crucial role in tumor progression and metastasis. Methods and Findings In this study, we investigated the potential roles and mechanisms of TLR2 signaling on tumor metastasis in a mouse model of intravenously injected B16 melanoma cells. Multiple subtypes of TLRs were expressed on B16 cells and several human cancer cell lines; TLR2 mediated the invasive activity of these cells. High metastatic B16 cells released more heat shock protein 60 than poor metastatic B16-F1 cells. Importantly, heat shock protein 60 released by tumor cells caused a persistent activation of TLR2 and was critical in the constitutive activation of transcription factor Stat3, leading to the release of immunosuppressive cytokines and chemokines. Moreover, targeting TLR2 markedly reduced pulmonary metastases and increased the survival of B16-bearing mice by reversing B16 cells induced immunosuppressive microenvironment and restoring tumor-killing cells such as CD8+ T cells and M1 macrophages. Combining an anti-TLR2 antibody and a cytotoxic agent, gemcitabine, provided a further improvement in the survival of tumor-bearing mice. Conclusions and Significance Our results demonstrate that TLR2 is an attractive target against metastasis and that targeting immunosuppressive microenvironment using anti-TLR2 antibody is a novel therapeutic strategy for combating a life-threatening metastasis.
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