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Augusto-Oliveira M, Tremblay MÈ, Verkhratsky A. Receptors on Microglia. ADVANCES IN NEUROBIOLOGY 2024; 37:83-121. [PMID: 39207688 DOI: 10.1007/978-3-031-55529-9_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Microglial cells are the most receptive cells in the central nervous system (CNS), expressing several classes of receptors reflecting their immune heritage and newly acquired neural specialisation. Microglia possess, depending on the particular context, receptors to neurotransmitters and neuromodulators as well as immunocompetent receptors. This rich complement allows microglial cells to monitor the functional status of the nervous system, contribute actively to the regulation of neural activity and plasticity and homeostasis, and guard against pathogens as well as other challenges to the CNS's integrity and function.
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Affiliation(s)
- Marcus Augusto-Oliveira
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
- Programa de Pós-Graduação em Farmacologia e Bioquímica, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | - Marie-Ève Tremblay
- Division of Medical Sciences, Medical Sciences Building, University of Victoria, Victoria, BC, Canada
- Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec City, QC, Canada
- Neurology and Neurosurgery Department, McGill University, Montreal, QC, Canada
- Department of Molecular Medicine, Université Laval, Pavillon Ferdinand-Vandry, Québec City, QC, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Life Sciences Center, Vancouver, BC, Canada
| | - Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, UK.
- Department of Neurosciences, University of the Basque Country, Leioa, Spain.
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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2
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Ratan Y, Rajput A, Maleysm S, Pareek A, Jain V, Pareek A, Kaur R, Singh G. An Insight into Cellular and Molecular Mechanisms Underlying the Pathogenesis of Neurodegeneration in Alzheimer's Disease. Biomedicines 2023; 11:biomedicines11051398. [PMID: 37239068 DOI: 10.3390/biomedicines11051398] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/04/2023] [Accepted: 05/06/2023] [Indexed: 05/28/2023] Open
Abstract
Alzheimer's disease (AD) is the most prominent neurodegenerative disorder in the aging population. It is characterized by cognitive decline, gradual neurodegeneration, and the development of amyloid-β (Aβ)-plaques and neurofibrillary tangles, which constitute hyperphosphorylated tau. The early stages of neurodegeneration in AD include the loss of neurons, followed by synaptic impairment. Since the discovery of AD, substantial factual research has surfaced that outlines the disease's causes, molecular mechanisms, and prospective therapeutics, but a successful cure for the disease has not yet been discovered. This may be attributed to the complicated pathogenesis of AD, the absence of a well-defined molecular mechanism, and the constrained diagnostic resources and treatment options. To address the aforementioned challenges, extensive disease modeling is essential to fully comprehend the underlying mechanisms of AD, making it easier to design and develop effective treatment strategies. Emerging evidence over the past few decades supports the critical role of Aβ and tau in AD pathogenesis and the participation of glial cells in different molecular and cellular pathways. This review extensively discusses the current understanding concerning Aβ- and tau-associated molecular mechanisms and glial dysfunction in AD. Moreover, the critical risk factors associated with AD including genetics, aging, environmental variables, lifestyle habits, medical conditions, viral/bacterial infections, and psychiatric factors have been summarized. The present study will entice researchers to more thoroughly comprehend and explore the current status of the molecular mechanism of AD, which may assist in AD drug development in the forthcoming era.
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Affiliation(s)
- Yashumati Ratan
- Department of Pharmacy, Banasthali Vidyapith, Banasthali 304022, Rajasthan, India
| | - Aishwarya Rajput
- Department of Pharmacy, Banasthali Vidyapith, Banasthali 304022, Rajasthan, India
| | - Sushmita Maleysm
- Department of Bioscience & Biotechnology, Banasthali Vidyapith, Banasthali 304022, Rajasthan, India
| | - Aaushi Pareek
- Department of Pharmacy, Banasthali Vidyapith, Banasthali 304022, Rajasthan, India
| | - Vivek Jain
- Department of Pharmaceutical Sciences, Mohan Lal Sukhadia University, Udaipur 313001, Rajasthan, India
| | - Ashutosh Pareek
- Department of Pharmacy, Banasthali Vidyapith, Banasthali 304022, Rajasthan, India
| | - Ranjeet Kaur
- Adesh Institute of Dental Sciences and Research, Bathinda 151101, Punjab, India
| | - Gurjit Singh
- Department of Biomedical Engineering, University of Illinois Chicago, Chicago, IL 60607, USA
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Monzón-Sandoval J, Burlacu E, Agarwal D, Handel AE, Wei L, Davis J, Cowley SA, Cader MZ, Webber C. Lipopolysaccharide distinctively alters human microglia transcriptomes to resemble microglia from Alzheimer's disease mouse models. Dis Model Mech 2022; 15:277958. [PMID: 36254682 PMCID: PMC9612871 DOI: 10.1242/dmm.049349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 08/30/2022] [Indexed: 01/15/2023] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia, and risk-influencing genetics implicates microglia and neuroimmunity in the pathogenesis of AD. Induced pluripotent stem cell (iPSC)-derived microglia (iPSC-microglia) are increasingly used as a model of AD, but the relevance of historical immune stimuli to model AD is unclear. We performed a detailed cross-comparison over time on the effects of combinatory stimulation of iPSC-microglia, and in particular their relevance to AD. We used single-cell RNA sequencing to measure the transcriptional response of iPSC-microglia after 24 h and 48 h of stimulation with prostaglandin E2 (PGE2) or lipopolysaccharide (LPS)+interferon gamma (IFN-γ), either alone or in combination with ATPγS. We observed a shared core transcriptional response of iPSC-microglia to ATPγS and to LPS+IFN-γ, suggestive of a convergent mechanism of action. Across all conditions, we observed a significant overlap, although directional inconsistency to genes that change their expression levels in human microglia from AD patients. Using a data-led approach, we identify a common axis of transcriptomic change across AD genetic mouse models of microglia and show that only LPS provokes a transcriptional response along this axis in mouse microglia and LPS+IFN-γ in human iPSC-microglia. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
| | - Elena Burlacu
- John Radcliffe Hospital, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DS, UK
| | - Devika Agarwal
- Nuffield Department of Medicine Research Building, Alzheimer's Research UK Oxford Drug Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK.,Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Adam E Handel
- John Radcliffe Hospital, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DS, UK
| | - Liting Wei
- James Martin Stem Cell Facility, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - John Davis
- Nuffield Department of Medicine Research Building, Alzheimer's Research UK Oxford Drug Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK
| | - Sally A Cowley
- Translational Molecular Neuroscience Group, New Biochemistry Building, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX1 3QU, UK
| | - M Zameel Cader
- John Radcliffe Hospital, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DS, UK.,James Martin Stem Cell Facility, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Caleb Webber
- UK Dementia Research Institute, Cardiff University, Cardiff CF24 4HQ, UK
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Nakayama M, Naito M, Omori K, Ono S, Nakayama K, Ohara N. Porphyromonas gingivalis Gingipains Induce Cyclooxygenase-2 Expression and Prostaglandin E 2 Production via ERK1/2-Activated AP-1 (c-Jun/c-Fos) and IKK/NF-κB p65 Cascades. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:1146-1154. [PMID: 35110422 DOI: 10.4049/jimmunol.2100866] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 12/13/2021] [Indexed: 06/14/2023]
Abstract
Porphyromonas gingivalis is commonly known as one of the major pathogens contributing to periodontitis, and its persistent infection may increase the risk for the disease. The proinflammatory mediators, including IL-6, TNF-α, and cyclooxygenase-2 (COX-2)/PGE2, are closely associated with progression of periodontitis. In this study, we focused on the cysteine protease "gingipains," lysine-specific gingipain, arginine-specific gingipain (Rgp) A, and RgpB, produced by P. gingivalis, and used the wild-type strain and several gene-deletion mutants (rgpA, rgpB, kgp, and fimA) to elucidate the involvement of gingipains in COX-2 expression and PGE2 production. We infected human monocytes, which are THP-1 cells and primary monocytes, with these bacterial strains and found that gingipains were involved in induction of COX-2 expression and PGE2 production. We have shown that the protease activity of gingipains was crucial for these events by using gingipain inhibitors. Furthermore, activation of ERK1/2 and IκB kinase was required for gingipain-induced COX-2 expression/PGE2 production, and these kinases activated two transcription factors, c-Jun/c-Fos (AP-1) and NF-κB p65, respectively. In particular, these data suggest that gingipain-induced c-Fos expression via ERK is essential for AP-1 formation with c-Jun, and activation of AP-1 and NF-κB p65 plays a central role in COX-2 expression/PGE2 production. Thus, we show the (to our knowledge) novel finding that gingipains with the protease activity from P. gingivalis induce COX-2 expression and PGE2 production via activation of MEK/ERK/AP-1 and IκB kinase/NF-κB p65 in human monocytes. Hence it is likely that gingipains closely contribute to the inflammation of periodontal tissues.
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Affiliation(s)
- Masaaki Nakayama
- Department of Oral Microbiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
- Advanced Research Center for Oral and Craniofacial Sciences, Dental School, Okayama University, Okayama, Japan
| | - Mariko Naito
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan; and
| | - Kazuhiro Omori
- Department of Periodontics and Endodontics, Okayama University Hospital, Okayama, Japan
- Advanced Research Center for Oral and Craniofacial Sciences, Dental School, Okayama University, Okayama, Japan
| | - Shintaro Ono
- Department of Periodontics and Endodontics, Okayama University Hospital, Okayama, Japan
| | - Koji Nakayama
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan; and
| | - Naoya Ohara
- Department of Oral Microbiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan;
- Advanced Research Center for Oral and Craniofacial Sciences, Dental School, Okayama University, Okayama, Japan
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Nagano T, Tsuda N, Fujimura K, Ikezawa Y, Higashi Y, Kimura SH. Prostaglandin E 2 increases the expression of cyclooxygenase-2 in cultured rat microglia. J Neuroimmunol 2021; 361:577724. [PMID: 34610503 DOI: 10.1016/j.jneuroim.2021.577724] [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: 06/30/2021] [Revised: 09/17/2021] [Accepted: 09/19/2021] [Indexed: 12/21/2022]
Abstract
Prostaglandin E2 (PGE2) plays pivotal roles in controlling microglial activation with the EP2 receptor, a PGE2 receptor subtype. Activated microglia are often reported to increase cyclooxygenase (COX)-2 expression, followed by PGE2 production, but it is unclear whether extracellular PGE2 is involved in microglial PGE2 synthesis. In the present study, we report that PGE2 increases COX-2 protein in microglia. In a culture system, PGE2 at 10-6 M for 3 h increased COX-2 and microsomal PGE synthase (mPGES)-1 mRNA levels, and reduced mPGES-2, but did not affect COX-1 or cytosolic PGE synthase (cPGES) in microglia. PGE2 at 10-6 M for 3 h also increased the COX-2 protein level, but did not affect COX-1, mPGES-1, mPGES-2, or cPGES. An EP2 agonist, ONO-AE1-259-01, also increased COX-2 and mPGES-1 mRNA levels, and reduced mPGES-2, but did not affect COX-1 or cPGES, whereas an EP1 agonist, ONO-DI-004, an EP3 agonist, ONO-AE-248, and an EP4 agonist, ONO-AE1-329, had no effect. Similar to PGE2, ONO-AE1-259-01 increased the COX-2 protein level, but did not affect COX-1, mPGES-1, mPGES-2, or cPGES. In addition, the effects of PGE2 were inhibited by an EP2 antagonist, PF-04418948, but not by an EP1 antagonist, ONO-8713, an EP3 antagonist, ONO-AE3-240, or an EP4 antagonist, ONO-AE3-208, at 10-6 M. On the other hand, lipopolysaccharide (LPS) increased PGE2 production, but the LPS-induced PGE2 production was not affected by ONO-8713, PF-04418948, ONO-AE3-240, or ONO-AE3-208. These results indicate that PGE2 increases COX-2 protein in microglia through the EP2 receptor supporting the idea that extracellular PGE2 has a triggering aspect for microglial activation.
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Affiliation(s)
- Takayuki Nagano
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
| | - Naohiko Tsuda
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Kenichi Fujimura
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Yuji Ikezawa
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Yuki Higashi
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Shinya H Kimura
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
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Xu Y, Liu Y, Li K, Miao S, Lv C, Wang C, Zhao J. Regulation of PGE 2 Pathway During Cerebral Ischemia Reperfusion Injury in Rat. Cell Mol Neurobiol 2021; 41:1483-1496. [PMID: 32621176 DOI: 10.1007/s10571-020-00911-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 06/22/2020] [Indexed: 01/14/2023]
Abstract
Stroke is an acute central nervous system disease with high morbidity and mortality rate. Cerebral ischemia reperfusion (I/R) injury is easily induced during the development or treatment of stroke and subsequently leads to more serious brain damage. Prostaglandin E2 (PGE2) is one of the most important inflammatory mediators in the brain and contributes to both physiological and pathophysiological functions. It may be upregulated and subsequently plays a key role in cerebral ischemia reperfusion injury. The synthesis and degradation of PGE2 is an extremely complex process, with multiple key stages and molecules. However, there are few comprehensive and systematic studies conducted to investigate the synthesis and degradation of PGE2 during cerebral I/R injury, which is what we want to demonstrate. In this study, qRT-PCR and immunoblotting demonstrated that the key enzymes in PGE2 synthesis, including COX-1, COX-2, mPGES-1 and mPGES-2, were upregulated during cerebral I/R injury, but 15-PGDH, the main PGE2 degradation enzyme, was downregulated. In addition, two of PGE2 receptors, EP3 and EP4, were also increased. Meanwhile, immunohistochemistry demonstrated the localization of these molecules in ischemic areas, including cortex, striatum and hippocampus, and reflected their expression patterns in different regions. Combining the results of PCR, Western blotting and immunohistochemistry, we can determine where the increase or decrease of these molecules occurs. Overall, these results further indicate a possible pathway that mediates enhanced production of PGE2, and thus that may impact production of inflammatory cytokines including IL-1β and TNF-α during cerebral I/R injury.
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Affiliation(s)
- Yunfei Xu
- Department of Pathophysiology, Xiangya School of Medicine, Central South University, Changsha, 410008, Hunan, China
- Sepsis Translational Medicine Key Lab of Hunan Province, Changsha, 410008, Hunan, China
| | - Ying Liu
- Department of Pathophysiology, Xiangya School of Medicine, Central South University, Changsha, 410008, Hunan, China.
- Sepsis Translational Medicine Key Lab of Hunan Province, Changsha, 410008, Hunan, China.
| | - Kexin Li
- Department of Pathophysiology, Xiangya School of Medicine, Central South University, Changsha, 410008, Hunan, China
- Sepsis Translational Medicine Key Lab of Hunan Province, Changsha, 410008, Hunan, China
| | - Shuying Miao
- Department of Pathology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, 210008, Jiangsu, China
| | - Caihong Lv
- Department of Pathophysiology, Xiangya School of Medicine, Central South University, Changsha, 410008, Hunan, China
- Sepsis Translational Medicine Key Lab of Hunan Province, Changsha, 410008, Hunan, China
| | - Chunjiang Wang
- Department of Pathophysiology, Xiangya School of Medicine, Central South University, Changsha, 410008, Hunan, China
- Sepsis Translational Medicine Key Lab of Hunan Province, Changsha, 410008, Hunan, China
| | - Jie Zhao
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
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Jiang J, Yu Y. Small molecules targeting cyclooxygenase/prostanoid cascade in experimental brain ischemia: Do they translate? Med Res Rev 2020; 41:828-857. [PMID: 33094540 DOI: 10.1002/med.21744] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/02/2020] [Accepted: 10/11/2020] [Indexed: 12/15/2022]
Abstract
Acute brain ischemia accounts for most of stroke cases and constitutes a leading cause of deaths among adults and permanent disabilities in survivors. Currently, the intravenous thrombolysis is the only available medication for ischemic stroke; mechanical thrombectomy is an emerging alternative treatment for occlusion of large arteries and has shown some promise in selected subsets of patients. However, the overall narrow treatment window and potential risks largely limit the patient eligibility. New druggable targets are needed to innovate the treatment of brain ischemia. As the rate-limiting enzyme in the biosyntheses of prostanoids, cyclooxygenase (COX), particularly the inducible isoform COX-2, has long been implicated in mechanisms of acute stroke-induced brain injury and inflammation. However, the notion of therapeutically targeting COX has been diminished over the past two decades due to significant complications of the cardiovascular and cerebrovascular systems caused by long-term use of COX-2 inhibitor drugs. New treatment strategies targeting the downstream prostanoid signaling receptors regulating the deleterious effects of COX cascade have been proposed. As such, a large number of selective small molecules that negatively or positively modulate these important inflammatory regulators have been evaluated for neuroprotection and other beneficial effects in various animal models of brain ischemia. These timely preclinical studies, though not yet led to clinical innovation, provided new insights into the regulation of inflammatory reactions in the ischemic brain and could guide drug discovery efforts aiming for novel adjunctive strategies, along with current reperfusion therapy, to treat acute brain ischemia with higher specificity and longer therapeutic window.
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Affiliation(s)
- Jianxiong Jiang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Ying Yu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
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Li L, Sluter MN, Yu Y, Jiang J. Prostaglandin E receptors as targets for ischemic stroke: Novel evidence and molecular mechanisms of efficacy. Pharmacol Res 2020; 163:105238. [PMID: 33053444 DOI: 10.1016/j.phrs.2020.105238] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/28/2020] [Accepted: 10/05/2020] [Indexed: 12/12/2022]
Abstract
Over the past two decades the interest has waned in therapeutically targeting cyclooxygenase-2 (COX-2) due to growing concerns over the potential cardiovascular and cerebrovascular toxicities of the long-term use of COX-2 inhibitors. Attention thus has recently been shifted downstream to the prostaglandin signaling pathways for new druggable anti-inflammatory targets aiming for higher therapeutic specificity. Prostaglandin E2 (PGE2) is robustly synthesized in the ischemic cortex by quickly induced COX-2 and microsomal prostaglandin E synthase-1 (mPGES-1) following cerebral ischemia. The elevated PGE2, in turn, divergently regulates the excitotoxic injury and neuroinflammation by acting on four membrane-bound G protein-coupled receptors (GPCRs), namely, EP1-EP4. Markedly, all four EP receptors have been implicated in the excitotoxicity-associated brain inflammation and injury in animal models of cerebral ischemia. However promising, these preclinical studies have not yet led to a clinical trial targeting any PGE2 receptor for ischemic stroke. The goal of this article is to review the recent progress in understanding the pathogenic roles of PGE2 in cerebral ischemia as well as to provide new mechanistic insights into the PGE2 signaling via these four GPCRs in neuronal excitotoxicity and inflammation. We also discuss the feasibility of targeting EP1-EP4 receptors as an emerging delayed treatment, together with the first-line reperfusion strategy, to manage acute ischemic stroke with potentially extended window as well as improved specificity.
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Affiliation(s)
- Lexiao Li
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Madison N Sluter
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Ying Yu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Jianxiong Jiang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA.
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Cao LL, Guan PP, Liang YY, Huang XS, Wang P. Cyclooxygenase-2 is Essential for Mediating the Effects of Calcium Ions on Stimulating Phosphorylation of Tau at the Sites of Ser 396 and Ser 404. J Alzheimers Dis 2020; 68:1095-1111. [PMID: 30883354 DOI: 10.3233/jad-181066] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Alzheimer's disease (AD) is reported to be associated with the accumulation of calcium ions (Ca2+), which is responsible for the phosphorylation of tau. Although a series of evidence have demonstrated this phenomenon, the inherent mechanisms remain unknown. Using tauP301S and cyclooxygenase-2 (COX-2) transgenic mice and neuroblastoma (n)2a cells as in vivo and in vitro experimental models, we found that Ca2+ stimulates the phosphorylation of tau by activating COX-2 in a prostaglandin (PG) E2-dependent EP receptor-activating manner. Specifically, Ca2+ incubation stimulated COX-2 and PGE2 synthase activity, microsomal PGE synthase 1 and the synthesis of PGE2 by activating the transcriptional activity of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in n2a cells. Elevated levels of PGE2 were responsible for phosphorylating tau in an EP-1, -2, and -3 but not EP4-dependent glycogen synthase kinase 3-activating manner. These observations were corroborated by results that showed tau was phosphorylated when it colocalized with activated COX-2 in tauP301S and COX-2 transgenic mice or n2a cells. To further validate these observations, treatment of mice with the COX-2 inhibitor rofecoxib decreased the phosphorylation of tau via EP1-3 but not EP4. Collectively, our observations fill the gaps between Ca2+ and the phosphorylation of tau in a COX-2-dependent mechanism, which potentially provides therapeutic targets for combating AD.
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Affiliation(s)
- Long-Long Cao
- College of Life and Health Sciences, Northeastern University, Shenyang, P. R. China
| | - Pei-Pei Guan
- College of Life and Health Sciences, Northeastern University, Shenyang, P. R. China
| | - Yun-Yue Liang
- College of Life and Health Sciences, Northeastern University, Shenyang, P. R. China
| | - Xue-Shi Huang
- College of Life and Health Sciences, Northeastern University, Shenyang, P. R. China
| | - Pu Wang
- College of Life and Health Sciences, Northeastern University, Shenyang, P. R. China
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10
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Rojas A, Banik A, Chen D, Flood K, Ganesh T, Dingledine R. Novel Microglia Cell Line Expressing the Human EP2 Receptor. ACS Chem Neurosci 2019; 10:4280-4292. [PMID: 31469538 DOI: 10.1021/acschemneuro.9b00311] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Recently, EP2 signaling pathways were shown to regulate the classical activation and death of microglia in rat primary microglial culture. The study of microglial cells has been challenging because they are time-consuming to isolate in culture, they are demanding in their growth requirements, and they have a limited lifespan. To circumvent these difficulties, we created a murine BV2 microglial cell line stably expressing human EP2 receptors (BV2-hEP2) and further explored EP2 modulation of microglial functions. The BV2-hEP2 cells displayed cAMP elevation when exposed to the selective EP2 receptor agonists (ONO-AE1-259-1 and CP544326), and this response was competitively inhibited by TG4-155, a selective EP2 antagonist (Schild KB = 2.6 nM). By contrast, untransfected BV2 cells were unresponsive to selective EP2 agonists. Similar to the case of rat primary microglia, BV2-hEP2 microglia treated with lipopolysaccharide (LPS) (100 ng/mL) displayed rapid and robust induction of the inflammatory mediators COX-2, IL-1β, TNFα, and IL-6. EP2 activation depressed TNFα induction but exacerbated that of the other inflammatory mediators. Like primary microglia, classically activated BV2 microglia phagocytose fluorescent-labeled latex microspheres. The presence of EP2, but not its activation by agonists, in BV2-hEP2 microglia reduced phagocytosis and proliferation by 65% and 32%, respectively, compared to BV2 microglia. Thus, BV2-hEP2 is the first microglial cell line that retains the EP2 modulation of immune regulation and phagocytic ability of native microglia. Suppression of phagocytosis by the EP2 protein appears unrelated to classical EP2 signaling pathways, which has implications for therapeutic development of EP2 antagonists.
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Affiliation(s)
- Asheebo Rojas
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Avijit Banik
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Di Chen
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Kevin Flood
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Thota Ganesh
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Raymond Dingledine
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia 30322, United States
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Burmeister AR, Johnson MB, Yaemmongkol JJ, Marriott I. Murine astrocytes produce IL-24 and are susceptible to the immunosuppressive effects of this cytokine. J Neuroinflammation 2019; 16:55. [PMID: 30825881 PMCID: PMC6397747 DOI: 10.1186/s12974-019-1444-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/24/2019] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Glia are key regulators of inflammatory responses within the central nervous system (CNS) following infection or trauma. We have previously demonstrated the ability of activated glia to rapidly produce pro-inflammatory mediators followed by a transition to an anti-inflammatory cytokine production profile that includes the immunosuppressive cytokine interleukin (IL)-10 and the closely related cytokine IL-19. IL-24, another member of the IL-10 family, has been studied in a number of inflammatory conditions in the periphery and is known to modulate immune cell activity. However, the ability of glia to produce IL-24 remains unclear and the effects of this pleiotropic cytokine on glial immune functions have not been investigated. METHODS In this study, we have assessed whether primary murine glia produce IL-24 following stimulation and evaluated the effect of this cytokine on the immune responses of such cells. We have utilized RT-PCR and immunoblot analyses to assess the expression of IL-24 and its cognate receptors by astrocytes following challenge with bacteria or their components. Furthermore, we have determined the effect of recombinant IL-24 on astrocyte immune signaling and responses to clinically relevant bacteria using RT-PCR and specific capture ELISAs. RESULTS We demonstrate that astrocytes express IL-24 mRNA and release detectable amounts of this cytokine protein in a delayed manner following bacterial challenge. In addition, we have determined that glia constitutively express the cognate receptors for IL-24 and show that such expression can be increased in astrocytes following activation. Importantly, our results indicate that IL-24 exerts an immunosuppressive effect on astrocytes by elevating suppressor of cytokine signaling 3 expression and limiting IL-6 production following challenge. Furthermore, we have demonstrated that IL-24 can also augment the release of IL-10 by bacterially challenged astrocytes and can induce the expression of the potentially neuroprotective mediators, glutamate transporter 1, and cyclooxygenase 2. CONCLUSIONS The expression of IL-24 and its cognate receptors by astrocytes following bacterial challenge, and the ability of this cytokine to limit inflammatory responses while promoting the expression of immunosuppressive and/or neuroprotective mediators, raises the intriguing possibility that IL-24 functions to regulate or resolve CNS inflammation following bacterial infection in order to limit neuronal damage.
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Affiliation(s)
- Amanda R. Burmeister
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223 USA
| | - M. Brittany Johnson
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223 USA
| | - Jessica J. Yaemmongkol
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223 USA
| | - Ian Marriott
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223 USA
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12
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Greenhalgh AD, Zarruk JG, Healy LM, Baskar Jesudasan SJ, Jhelum P, Salmon CK, Formanek A, Russo MV, Antel JP, McGavern DB, McColl BW, David S. Peripherally derived macrophages modulate microglial function to reduce inflammation after CNS injury. PLoS Biol 2018; 16:e2005264. [PMID: 30332405 PMCID: PMC6205650 DOI: 10.1371/journal.pbio.2005264] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 10/29/2018] [Accepted: 10/01/2018] [Indexed: 12/19/2022] Open
Abstract
Infiltrating monocyte-derived macrophages (MDMs) and resident microglia dominate central nervous system (CNS) injury sites. Differential roles for these cell populations after injury are beginning to be uncovered. Here, we show evidence that MDMs and microglia directly communicate with one another and differentially modulate each other's functions. Importantly, microglia-mediated phagocytosis and inflammation are suppressed by infiltrating macrophages. In the context of spinal cord injury (SCI), preventing such communication increases microglial activation and worsens functional recovery. We suggest that macrophages entering the CNS provide a regulatory mechanism that controls acute and long-term microglia-mediated inflammation, which may drive damage in a variety of CNS conditions.
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Affiliation(s)
- Andrew D. Greenhalgh
- Centre for Research in Neuroscience, The Research Institute of the McGill University Health Center, Quebec, Canada
- Laboratory of Nutrition and Integrated Neurobiology, UMR INRA 1286, University of Bordeaux, Bordeaux, France
| | - Juan G. Zarruk
- Centre for Research in Neuroscience, The Research Institute of the McGill University Health Center, Quebec, Canada
| | - Luke M. Healy
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Sam J. Baskar Jesudasan
- Centre for Research in Neuroscience, The Research Institute of the McGill University Health Center, Quebec, Canada
| | - Priya Jhelum
- Centre for Research in Neuroscience, The Research Institute of the McGill University Health Center, Quebec, Canada
| | - Christopher K. Salmon
- Centre for Research in Neuroscience, The Research Institute of the McGill University Health Center, Quebec, Canada
| | - Albert Formanek
- Centre for Research in Neuroscience, The Research Institute of the McGill University Health Center, Quebec, Canada
| | - Matthew V. Russo
- Viral Immunology and Intravital Imaging Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jack P. Antel
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Dorian B. McGavern
- Viral Immunology and Intravital Imaging Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Barry W. McColl
- UK Dementia Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Samuel David
- Centre for Research in Neuroscience, The Research Institute of the McGill University Health Center, Quebec, Canada
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13
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Current Concepts of Neurodegenerative Mechanisms in Alzheimer's Disease. BIOMED RESEARCH INTERNATIONAL 2018; 2018:3740461. [PMID: 29707568 PMCID: PMC5863339 DOI: 10.1155/2018/3740461] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 02/07/2018] [Indexed: 02/06/2023]
Abstract
Neurodegenerative diseases are hereditary or sporadic conditions that result in the progressive loss of the structure and function of neurons as well as neuronal death. Although a range of diseases lie under this umbrella term, Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common neurodegenerative diseases that affect a large population around the globe. Alzheimer's disease is characterized by the abnormal accumulation of extracellular amyloid-β plaques and intraneuronal neurofibrillary tangles in brain regions and manifests as a type of dementia in aged individuals that results in memory loss, multiple cognitive abnormalities, and intellectual disabilities that interfere with quality of life. Since the discovery of AD, a wealth of new information has emerged that delineates the causes, mechanisms of disease, and potential therapeutic agents, but an effective remedy to cure the diseases has not been identified yet. This could be because of the complexity of the disease process, as it involves various contributing factors that include environmental factors and genetic predispositions. This review summarizes the current understanding on neurodegenerative mechanisms that lead to the emergence of the pathology of AD.
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14
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Chen SH, Sung YF, Oyarzabal EA, Tan YM, Leonard J, Guo M, Li S, Wang Q, Chu CH, Chen SL, Lu RB, Hong JS. Physiological Concentration of Prostaglandin E 2 Exerts Anti-inflammatory Effects by Inhibiting Microglial Production of Superoxide Through a Novel Pathway. Mol Neurobiol 2018; 55:8001-8013. [PMID: 29492849 DOI: 10.1007/s12035-018-0965-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 02/16/2018] [Indexed: 01/21/2023]
Abstract
This study investigated the physiological regulation of brain immune homeostasis in rat primary neuron-glial cultures by sub-nanomolar concentrations of prostaglandin E2 (PGE2). We demonstrated that 0.01 to 10 nM PGE2 protected dopaminergic neurons against LPS-induced neurotoxicity through a reduction of microglial release of pro-inflammatory factors in a dose-dependent manner. Mechanistically, neuroprotective effects elicited by PGE2 were mediated by the inhibition of microglial NOX2, a major superoxide-producing enzyme. This conclusion was supported by (1) the close relationship between inhibition of superoxide and PGE2-induced neuroprotective effects; (2) the mediation of PGE2-induced reduction of superoxide and neuroprotection via direct inhibition of the catalytic subunit of NOX2, gp91phox, rather than through the inhibition of conventional prostaglandin E2 receptors; and (3) abolishment of the neuroprotective effect of PGE2 in NOX2-deficient cultures. In summary, this study revealed a potential physiological role of PGE2 in maintaining brain immune homeostasis and protecting neurons via an EP receptor-independent mechanism.
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Affiliation(s)
- Shih-Heng Chen
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, NIEHS/NIH, 111 T.W. Alexander Dr., Research Triangle Park, NC, 27709, USA.
| | - Yueh-Feng Sung
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, NIEHS/NIH, 111 T.W. Alexander Dr., Research Triangle Park, NC, 27709, USA.,Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Esteban A Oyarzabal
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, NIEHS/NIH, 111 T.W. Alexander Dr., Research Triangle Park, NC, 27709, USA
| | - Yu-Mei Tan
- U.S. Environmental Protection Agency, National Exposure Research Lab, Research Triangle Park, NC, USA
| | - Jeremy Leonard
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA
| | - Mingri Guo
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, NIEHS/NIH, 111 T.W. Alexander Dr., Research Triangle Park, NC, 27709, USA.,Department of Laboratory Medicine, Tianjin Haihe Hospital/Haihe Clinical Institute of Tianjin Medical University, Tianjin, China
| | - Shuo Li
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, NIEHS/NIH, 111 T.W. Alexander Dr., Research Triangle Park, NC, 27709, USA.,Department of Respiratory, Tianjin Medical University General Hospital, Tianjin, China
| | - Qingshan Wang
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, NIEHS/NIH, 111 T.W. Alexander Dr., Research Triangle Park, NC, 27709, USA
| | - Chun-Hsien Chu
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, NIEHS/NIH, 111 T.W. Alexander Dr., Research Triangle Park, NC, 27709, USA
| | - Shiou-Lan Chen
- Department of Neurology, School of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Ru-Band Lu
- Institute of Behavioral Medicine, College of Medicine & Hospital, National Cheng Kung University, Tainan, Taiwan.,Department of Psychiatry, National Cheng Kung University, Tainan, Taiwan
| | - Jau-Shyong Hong
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, NIEHS/NIH, 111 T.W. Alexander Dr., Research Triangle Park, NC, 27709, USA.
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15
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Yousif NM, de Oliveira ACP, Brioschi S, Huell M, Biber K, Fiebich BL. Activation of EP 2 receptor suppresses poly(I: C) and LPS-mediated inflammation in primary microglia and organotypic hippocampal slice cultures: Contributing role for MAPKs. Glia 2017; 66:708-724. [PMID: 29226424 DOI: 10.1002/glia.23276] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/08/2017] [Accepted: 11/17/2017] [Indexed: 12/26/2022]
Abstract
Brain inflammation is a critical factor involved in neurodegeneration. Recently, the prostaglandin E2 (PGE2 ) downstream members were suggested to modulate neuroinflammatory responses accompanying neurodegenerative diseases. In this study, we investigated the protective effects of prostaglandin E2 receptor 2 (EP2 ) during TLR3 and TLR4-driven inflammatory response using in vitro primary microglia and ex vivo organotypic hippocampal slice cultures (OHSCs). Depletion of microglia from OHSCs differentially affected TLR3 and TLR4 receptor expression. Poly(I:C) induced the production of prostaglandin E2 in OHSCs by increasing cyclooxygenase (COX-2) and microsomal prostaglandin E synthase (mPGES)-1. Besides, stimulation of OHSCs and microglia with Poly(I:C) upregulated EP2 receptor expression. Co-stimulation of OHSCs and microglia with the EP2 agonist butaprost reduced inflammatory mediators induced by LPS and Poly(I:C). In Poly(I:C) challenged OHSCs, butaprost almost restored microglia ramified morphology and reduced Iba1 immunoreactivity. Importantly, microglia depletion prevented the induction of inflammatory mediators following Poly(I:C) or LPS challenge in OHSCs. Activation of EP2 receptor reversed the Poly(I:C)/LPS-induced phosphorylation of the mitogen activated protein kinases (MAPKs) ERK, p38 MAPK and c-Jun N-terminal kinase (JNK) in microglia. Collectively, these data identify an anti-inflammatory function for EP2 signaling in diverse innate immune responses, through a mechanism that involves the mitogen-activated protein kinases pathway.
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Affiliation(s)
- Nizar M Yousif
- Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hauptstr. 5, Freiburg, D-79104, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | | | - Simone Brioschi
- Faculty of Biology, University of Freiburg, Freiburg, Germany
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hauptstr. 5, Freiburg, D-79104, Germany
| | - Michael Huell
- Zentrum für Psychiatrie Emmendingen, Neubronnstr. 25, Emmendingen, 79312
| | - Knut Biber
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hauptstr. 5, Freiburg, D-79104, Germany
| | - Bernd L Fiebich
- Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hauptstr. 5, Freiburg, D-79104, Germany
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16
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King JR, Gillevet TC, Kabbani N. A G protein-coupled α7 nicotinic receptor regulates signaling and TNF-α release in microglia. FEBS Open Bio 2017; 7:1350-1361. [PMID: 28904864 PMCID: PMC5586346 DOI: 10.1002/2211-5463.12270] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 07/14/2017] [Indexed: 11/21/2022] Open
Abstract
Acetylcholine activation of α7 nicotinic acetylcholine receptors (α7 nAChRs) in microglia attenuates neuroinflammation and regulates TNF‐α release. We used lipopolysaccharide to model inflammation in the microglial cell line EOC20 and examined signaling by the α7 nAChR. Co‐immunoprecipitation experiments confirm that α7 nAChRs bind heterotrimeric G proteins in EOC20 cells. Interaction with Gαi mediates α7 nAChR signaling via enhanced intracellular calcium release and a decrease in cAMP, p38 phosphorylation, and TNF‐α release. These α7 nAChR effects were blocked by the inhibition of Gαi signaling via pertussis toxin, PLC activity with U73122, and α7 nAChR channel activity with the selective antagonist α‐bungarotoxin. Moreover, α7 nAChR signaling in EOC20 cells was significantly diminished by the expression of a dominant‐negative α7 nAChR, α7345‐8A, shown to be impaired in G protein binding. These findings indicate an essential role for G protein coupling in α7 nAChR function in microglia leading to the regulation of inflammation in the nervous system.
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Affiliation(s)
- Justin R King
- Interdisciplinary Program in Neuroscience Krasnow Institute for Advanced Study George Mason University Fairfax VA USA
| | - Trudy C Gillevet
- Interdisciplinary Program in Neuroscience Krasnow Institute for Advanced Study George Mason University Fairfax VA USA
| | - Nadine Kabbani
- School of Systems Biology Krasnow Institute for Advanced Study George Mason University Fairfax VA USA
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17
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Stucky EC, Erndt-Marino J, Schloss RS, Yarmush ML, Shreiber DI. Prostaglandin E 2 Produced by Alginate-Encapsulated Mesenchymal Stromal Cells Modulates the Astrocyte Inflammatory Response. NANO LIFE 2017; 7:1750005. [PMID: 29682085 PMCID: PMC5903452 DOI: 10.1142/s1793984417500052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Astroglia are well known for their role in propagating secondary injury following brain trauma. Modulation of this injury cascade, including inflammation, is essential to repair and recovery. Mesenchymal stromal cells (MSCs) have been demonstrated as trophic mediators in several models of secondary CNS injury, however, there has been varied success with the use of direct implantation due to a failure to persist at the injury site. To achieve sustained therapeutic benefit, we have encapsulated MSCs in alginate microspheres and evaluated the ability of these encapsulated MSCs to attenuate neuro-inflammation. In this study, astroglial cultures were administered lipopolysaccharide (LPS) to induce inflammation and immediately co-cultured with encapsulated or monolayer human MSCs. Cultures were assayed for the pro-inflammatory cytokine tumor necrosis factor alpha (TNF-α) produced by astroglia, MSC-produced prostaglandin E2, and expression of neurotrophin-associated genes. We found that encapsulated MSCs significantly reduced TNF-α produced by LPS-stimulated astrocytes, more effectively than monolayer MSCs, and this enhanced benefit commences earlier than that of monolayer MSCs. Furthermore, in support of previous findings, encapsulated MSCs constitutively produced high levels of PGE2, while monolayer MSCs required the presence of inflammatory stimuli to induce PGE2 production. The early, constitutive presence of PGE2 significantly reduced astrocyte-produced TNF-α, while delayed administration had no effect. Finally, MSC-produced PGE2 was not only capable of modulating inflammation, but appears to have an additional role in stimulating astrocyte neurotrophin production. Overall, these results support the enhanced benefit of encapsulated MSC treatment, both in modulating the inflammatory response and providing neuroprotection.
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Affiliation(s)
- Elizabeth C Stucky
- Department of Chemical and Biochemical Engineering, Rutgers University, 599 Taylor Road, Piscataway, New Jersey 08854, USA
| | - Joshua Erndt-Marino
- Department of Biomedical Engineering, The College of New Jersey, 2000 Pennington Road, Ewing, New Jersey 08628, USA
| | - Rene S Schloss
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, New Jersey 08854, USA
| | - Martin L Yarmush
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, New Jersey 08854, USA
| | - David I Shreiber
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, New Jersey 08854, USA
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18
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Nagano T, Nishiyama R, Sanada A, Mutaguchi Y, Ioku A, Umeki H, Kishimoto S, Yamanaka D, Kimura SH, Takemura M. Prostaglandin E 2 potentiates interferon-γ-induced nitric oxide production in cultured rat microglia. J Neurochem 2017; 140:605-612. [PMID: 27973680 DOI: 10.1111/jnc.13926] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 11/30/2016] [Accepted: 12/06/2016] [Indexed: 12/26/2022]
Abstract
Prostaglandin E2 (PGE2 ) plays crucial roles in managing microglial activation through the prostanoid EP2 receptor, a PGE2 receptor subtype. In this study, we report that PGE2 enhances interferon-γ (IFN-γ)-induced nitric oxide production in microglia. IFN-γ increased the release of nitrite, a metabolite of nitric oxide, which was augmented by PGE2 , although PGE2 by itself slightly affects nitrite release. The potentiating effect of PGE2 was positively associated with increased expression of inducible nitric oxide synthase. In contrast to nitrite release induced by IFN-γ, lipopolysaccharide-induced nitrite release was not affected by PGE2 . An EP2 agonist, ONO-AE1-259-01 also augmented IFN-γ-induced nitrite release, while an EP1 agonist, ONO-DI-004, an EP3 agonist, ONO-AE-248, or an EP4 agonist, ONO-AE1-329, did not. In addition, the potentiating effect of PGE2 was inhibited by an EP2 antagonist, PF-04418948, but not by an EP1 antagonist, ONO-8713, an EP3 antagonist, ONO-AE3-240, or an EP4 antagonist, ONO-AE3-208, at 10-6 M. Among the EP agonists, ONO-AE1-259-01 alone was able to accumulate cyclic adenosine monophosphate (AMP), and among the EP antagonists, PF-04418948 was the only one able to inhibit PGE2 -increased intracellular cyclic AMP accumulation. On the other hand, IFN-γ promoted phosphorylation of signal transducer and activator of transcription 1, which was not affected by PGE2 . Furthermore, other prostanoid receptor agonists, PGD2 , PGF2α , iloprost, and U-46119, slightly affected IFN-γ-induced nitrite release. These results indicate that PGE2 potentiates IFN-γ-induced nitric oxide production in microglia through the EP2 receptor, which may shed light on one of the pro-inflammatory aspects of PGE2 .
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Affiliation(s)
- Takayuki Nagano
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Ryo Nishiyama
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Ayaka Sanada
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Yukiko Mutaguchi
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Anna Ioku
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Hirohisa Umeki
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Satoshi Kishimoto
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Daisuke Yamanaka
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Shinya H Kimura
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Motohiko Takemura
- Department of Pharmacology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
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19
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Wu H, Wu T, Han X, Wan J, Jiang C, Chen W, Lu H, Yang Q, Wang J. Cerebroprotection by the neuronal PGE2 receptor EP2 after intracerebral hemorrhage in middle-aged mice. J Cereb Blood Flow Metab 2017; 37:39-51. [PMID: 26746866 PMCID: PMC5363749 DOI: 10.1177/0271678x15625351] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 11/20/2015] [Accepted: 12/01/2015] [Indexed: 11/16/2022]
Abstract
Inflammatory responses mediated by prostaglandins such as PGE2 may contribute to secondary brain injury after intracerebral hemorrhage (ICH). However, the cell-specific signaling by PGE2 receptor EP2 differs depending on whether the neuropathic insult is acute or chronic. Using genetic and pharmacologic approaches, we investigated the role of EP2 receptor in two mouse models of ICH induced by intrastriatal injection of collagenase or autologous arterial whole blood. We used middle-aged male mice to enhance the clinical relevance of the study. EP2 receptor was expressed in neurons but not in astrocytes or microglia after collagenase-induced ICH. Brain injury after collagenase-induced ICH was associated with enhanced cellular and molecular inflammatory responses, oxidative stress, and matrix metalloproteinase (MMP)-2/9 activity. EP2 receptor deletion exacerbated brain injury, brain swelling/edema, neuronal death, and neurobehavioral deficits, whereas EP2 receptor activation by the highly selective agonist AE1-259-01 reversed these outcomes. EP2 receptor deletion also exacerbated brain edema and neurologic deficits in the blood ICH model. These findings support the premise that neuronal EP2 receptor activation by PGE2 protects brain against ICH injury in middle-aged mice through its anti-inflammatory and anti-oxidant effects and anti-MMP-2/9 activity. PGE2/EP2 signaling warrants further investigation for potential use in ICH treatment.
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Affiliation(s)
- He Wu
- Department of Pathology, First Clinical Hospital, Harbin Medical University, Harbin, China
| | - Tao Wu
- Stroke Center, Stroke Screening and Intervention Base, Changhai Hospital, Second Military Medical University, Shanghai, China.,Department of Anesthesiology/Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, USA
| | - Xiaoning Han
- Department of Anesthesiology/Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, USA
| | - Jieru Wan
- Department of Anesthesiology/Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, USA
| | - Chao Jiang
- Department of Anesthesiology/Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, USA
| | - Wenwu Chen
- Department of Anesthesiology/Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, USA
| | - Hong Lu
- Department of Neurology, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Qingwu Yang
- Department of Neurology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Jian Wang
- Department of Anesthesiology/Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, USA
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20
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Karababa A, Groos-Sahr K, Albrecht U, Keitel V, Shafigullina A, Görg B, Häussinger D. Ammonia Attenuates LPS-Induced Upregulation of Pro-Inflammatory Cytokine mRNA in Co-Cultured Astrocytes and Microglia. Neurochem Res 2016; 42:737-749. [PMID: 27655254 DOI: 10.1007/s11064-016-2060-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 09/03/2016] [Accepted: 09/08/2016] [Indexed: 12/19/2022]
Abstract
Hepatic encephalopathy (HE) is associated with cerebral microglia activation. Ammonia, a major toxin of HE, activates microglia in vitro but does not trigger pro-inflammatory cytokine synthesis. In the present study we analysed effects of ammonia on lipopolysaccharide (LPS)-induced upregulation of microglia activation and cytokine mRNA as well as on cytokine secretion in mono-cultured microglia and co-cultured astrocytes and microglia. In mono-cultured microglia LPS (100 ng/ml, 18 h) strongly elevated mRNA levels of the microglia activation marker CD14 and the pro-inflammatory cytokines IL-1α/β, IL-6 and TNF-α. NH4Cl (5 mmol/l) had no effect on LPS-induced upregulation of CD14, IL-1α/β and IL-6 mRNA but enhanced LPS-induced upregulation of TNF-α mRNA in mono-cultured microglia. In co-cultured astrocytes and microglia, however, LPS-induced upregulation of IL-1α/β, TNF-α, IL-6, CD14 but not of IL-10, IL-12A/B or TGFβ1-3 mRNA was attenuated by NH4Cl. LPS-induced upregulation of IL-1α/β, IL-6 and TNF-α was also diminished by the TGR5-ligands allopregnanolone and taurolithocholic acid in mono-cultured microglia. NH4Cl also attenuated LPS-induced release of MCP-1, IL-6 and IL-10 in mono-cultured microglia. mRNA level of surrogate marker for microglia activation (CD14) and for the anti-inflammatory M2-type microglia (CD163, CXCL1, CXCL2) were also elevated in post mortem brain tissue taken from the fusiforme gyrus of patients with liver cirrhosis and HE. The findings suggest that ammonia attenuates LPS-induced microglia reactivity in an astrocyte-dependent way. One may speculate that these anti-inflammatory effects of ammonia may be triggered by neurosteroids derived from astrocytes and may account for absence of microglia reactivity in cerebral cortex of cirrhotic patients with HE.
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Affiliation(s)
- Ayse Karababa
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, D-40225, Düsseldorf, Germany
| | - Katerina Groos-Sahr
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, D-40225, Düsseldorf, Germany
| | - Ute Albrecht
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, D-40225, Düsseldorf, Germany
| | - Verena Keitel
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, D-40225, Düsseldorf, Germany
| | - Aygul Shafigullina
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, D-40225, Düsseldorf, Germany
| | - Boris Görg
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, D-40225, Düsseldorf, Germany
| | - Dieter Häussinger
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, D-40225, Düsseldorf, Germany.
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Fiedler SE, Kerns AR, Tsang C, Tsang V, Bourdette D, Salinthone S. Dimethyl fumarate activates the prostaglandin EP2 receptor and stimulates cAMP signaling in human peripheral blood mononuclear cells. Biochem Biophys Res Commun 2016; 475:19-24. [PMID: 27157139 DOI: 10.1016/j.bbrc.2016.05.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 05/05/2016] [Indexed: 02/05/2023]
Abstract
Dimethyl fumarate (DMF) was recently approved by the FDA for the treatment of relapsing remitting MS. The pathology of MS is a result of both immune dysregulation and oxidative stress induced damage, and DMF is believed to have therapeutic effects on both of these processes. However, the mechanisms of action of DMF are not fully understood. To determine if DMF is able to activate signaling cascades that affect immune dysregulation, we treated human peripheral blood mononuclear cells with DMF. We discovered that DMF stimulates cyclic adenosine monophosphate (cAMP) production after 1 min treatment in vitro. cAMP is a small molecule second messenger that has been shown to modulate immune response. Using pharmacological inhibitors, we determined that adenylyl cyclase mediates DMF induced cAMP production; DMF activated the prostaglandin EP2 receptor to produce cAMP. This response was not due to increased endogenous production of prostaglandin E2 (PGE2), but was enhanced by addition of exogenous PGE2. Furthermore, we determined that the bioactive metabolite of DMF, monomethyl fumarate (MMF), also stimulates cAMP production. These novel findings suggest that DMF may provide protection against MS by inhibiting immune cell function via the cAMP signaling pathway.
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Affiliation(s)
- Sarah E Fiedler
- VA Portland Health Care System, Research and Development Service, 3710 SW US Veterans' Hospital Rd., Portland, OR 97239, USA
| | - Amelia R Kerns
- VA Portland Health Care System, Research and Development Service, 3710 SW US Veterans' Hospital Rd., Portland, OR 97239, USA
| | - Catherine Tsang
- VA Portland Health Care System, Research and Development Service, 3710 SW US Veterans' Hospital Rd., Portland, OR 97239, USA
| | - Vivian Tsang
- VA Portland Health Care System, Research and Development Service, 3710 SW US Veterans' Hospital Rd., Portland, OR 97239, USA
| | - Dennis Bourdette
- VA Portland Health Care System, Research and Development Service, 3710 SW US Veterans' Hospital Rd., Portland, OR 97239, USA; Department of Neurology, Oregon Health & Sciences University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239, USA
| | - Sonemany Salinthone
- VA Portland Health Care System, Research and Development Service, 3710 SW US Veterans' Hospital Rd., Portland, OR 97239, USA; Department of Neurology, Oregon Health & Sciences University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239, USA.
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22
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Leclerc JL, Lampert AS, Diller MA, Doré S. PGE2-EP3 signaling exacerbates intracerebral hemorrhage outcomes in 24-mo-old mice. Am J Physiol Heart Circ Physiol 2016; 310:H1725-34. [PMID: 27084388 DOI: 10.1152/ajpheart.00638.2015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 04/07/2016] [Indexed: 01/15/2023]
Abstract
With the population aging at an accelerated rate, the prevalence of stroke and financial burden of stroke-related health care costs are expected to continue to increase. Intracerebral hemorrhage (ICH) is a devastating stroke subtype more commonly affecting the elderly population, who display increased mortality and worse functional outcomes compared with younger patients. This study aimed to investigate the contribution of the prostaglandin E2 (PGE2) E prostanoid (EP) receptor subtype 3 in modulating anatomical outcomes and functional recovery following ICH in 24-mo-old mice. EP3 is the most abundant EP receptor in the brain and we have previously shown that signaling through the PGE2-EP3 axis exacerbates ICH outcomes in young mice. Here, we show that EP3 receptor deletion results in 17.9 ± 6.1% less ICH-induced brain injury (P < 0.05) and improves neurological functional recovery (P < 0.01), as identified by lower neurological deficit scores, decreased resting time, and more gross and fine motor movements. Immunohistological staining was performed to investigate possible mechanisms of EP3-mediated neurotoxicity. Identified mechanisms include reduced blood accumulation and modulation of angiogenic and astroglial responses. Using this aged cohort of mice, we have confirmed and extended our previous results in young mice demonstrating the deleterious role of the PGE2-EP3 signaling axis in modulating brain injury and functional recovery after ICH, further supporting the notion of the EP3 receptor as a putative therapeutic avenue for the treatment of ICH.
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Affiliation(s)
- Jenna L Leclerc
- Department of Anesthesiology, University of Florida, Gainesville, Florida; Department of Neuroscience, University of Florida, Gainesville, Forida; and
| | - Andrew S Lampert
- Department of Anesthesiology, University of Florida, Gainesville, Florida
| | - Matthew A Diller
- Department of Anesthesiology, University of Florida, Gainesville, Florida
| | - Sylvain Doré
- Department of Anesthesiology, University of Florida, Gainesville, Florida; Department of Neuroscience, University of Florida, Gainesville, Forida; and Departments of Neurology, Psychiatry, Psychology and Pharmaceutics, University of Florida, Gainesville, Florida
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23
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Tse KH, Chow KBS, Wise H. PGE2 released by primary sensory neurons modulates Toll-like receptor 4 activities through an EP4 receptor-dependent process. J Neuroimmunol 2016; 293:8-16. [PMID: 27049555 DOI: 10.1016/j.jneuroim.2016.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/28/2016] [Accepted: 02/08/2016] [Indexed: 11/20/2022]
Abstract
Exogenous prostaglandin E2 (PGE2) displays mixed regulatory properties with regard to inflammatory gene expression in dorsal root ganglion (DRG) cells. We show here that endogenously-produced nanomolar concentrations of PGE2, such as that generated in response to Toll-like receptor 4 (TLR4) stimulation, inhibits both cyclooxygenase-2 (COX-2) and tumour necrosis factor alpha (TNFα) mRNA expression in DRG cells in an EP4 receptor-dependent manner. DRG neurons appear to be the major source of PGE2 in the DRG and likely serve as both an autocrine and paracrine system for limiting over-activation of both DRG neurons and glial cells in response to TLR4 stimulation.
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Affiliation(s)
- Kai-Hei Tse
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China.
| | - Kevin B S Chow
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Helen Wise
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
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24
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Sil S, Ghosh T. Role of cox-2 mediated neuroinflammation on the neurodegeneration and cognitive impairments in colchicine induced rat model of Alzheimer's Disease. J Neuroimmunol 2015; 291:115-24. [PMID: 26857505 DOI: 10.1016/j.jneuroim.2015.12.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 11/30/2015] [Accepted: 12/09/2015] [Indexed: 11/15/2022]
Abstract
The neurodegeneration in colchicine induced AD (cAD) rats is linked with neuroinflammation. The inducible cox-2 present in the brain may participate in the neuroinflammatory process related to progressive neurodegeneration in cAD rats. The aim of this study is to investigate the role of cox-2 in the neurodegeneration and cognitive impairments in cAD rats. The parameters of memory (working and reference memory), inflammatory markers [IL-1β, TNF-α, prostaglandin E2 (PGE2), cox-2 level] and histopathology of hippocampus were measured after 21-day of i.c.v. colchicine injection in rats and compared with that of control and sham operated rats. These parameters were also measured in these 3 different groups of rats after p.o. administration of 3 different doses of etoricoxib, a cox 2 inhibitor. The impairments of working and reference memory were associated with neuroinflammation and neurodegeneration in the hippocampus and increased cox-2 and PGE2 levels in hippocampus in cAD. Administration of etoricoxib in cAD rats resulted in recovery of memory impairments, neurodegeneration and neuroinflammation in hippocampus and inhibition of cox-2 and PGE2 levels in hippocampus. It appears from the results that activation of cox-2 in cAD is related to neuroinflammation involved in neurodegeneration. Colchicine induced initial neurodegeneration may trigger cascade of events for a progressive neurodegeneration where cox-2 activation plays a critical role. Moreover, this cox-2 mediated neurodegeneration is related to impairments of memory parameters. Thus, the present study showed that the impairments of memory and neurodegeneration in the hippocampus of cAD in 21-day study are mediated by cox-2 induced neuroinflammation.
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Affiliation(s)
- Susmita Sil
- Neurophysiology laboratory, Department of Physiology, University College of Science and Technology, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata 700 009, West Bengal, India.
| | - Tusharkanti Ghosh
- Neurophysiology laboratory, Department of Physiology, University College of Science and Technology, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata 700 009, West Bengal, India.
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25
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Fox BM, Beck HP, Roveto PM, Kayser F, Cheng Q, Dou H, Williamson T, Treanor J, Liu H, Jin L, Xu G, Ma J, Wang S, Olson SH. A Selective Prostaglandin E2 Receptor Subtype 2 (EP2) Antagonist Increases the Macrophage-Mediated Clearance of Amyloid-Beta Plaques. J Med Chem 2015; 58:5256-73. [DOI: 10.1021/acs.jmedchem.5b00567] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Brian M. Fox
- Amgen South San Francisco, Amgen Inc., 1120 Veterans
Boulevard, South San Francisco, California 94080, United States
| | - Hilary P. Beck
- Amgen South San Francisco, Amgen Inc., 1120 Veterans
Boulevard, South San Francisco, California 94080, United States
| | - Philip M. Roveto
- Amgen South San Francisco, Amgen Inc., 1120 Veterans
Boulevard, South San Francisco, California 94080, United States
| | - Frank Kayser
- Amgen South San Francisco, Amgen Inc., 1120 Veterans
Boulevard, South San Francisco, California 94080, United States
| | - Qingwen Cheng
- Amgen South San Francisco, Amgen Inc., 1120 Veterans
Boulevard, South San Francisco, California 94080, United States
| | - Hannah Dou
- Amgen South San Francisco, Amgen Inc., 1120 Veterans
Boulevard, South San Francisco, California 94080, United States
| | - Toni Williamson
- Amgen Inc., One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - James Treanor
- Amgen South San Francisco, Amgen Inc., 1120 Veterans
Boulevard, South San Francisco, California 94080, United States
| | - Hantao Liu
- Amgen Inc., One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Lixia Jin
- Amgen South San Francisco, Amgen Inc., 1120 Veterans
Boulevard, South San Francisco, California 94080, United States
| | - Guifen Xu
- Amgen South San Francisco, Amgen Inc., 1120 Veterans
Boulevard, South San Francisco, California 94080, United States
| | - Ji Ma
- Amgen South San Francisco, Amgen Inc., 1120 Veterans
Boulevard, South San Francisco, California 94080, United States
| | - Songli Wang
- Amgen South San Francisco, Amgen Inc., 1120 Veterans
Boulevard, South San Francisco, California 94080, United States
| | - Steven H. Olson
- Amgen South San Francisco, Amgen Inc., 1120 Veterans
Boulevard, South San Francisco, California 94080, United States
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26
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Leclerc JL, Lampert AS, Diller MA, Doré S. Genetic deletion of the prostaglandin E2 E prostanoid receptor subtype 3 improves anatomical and functional outcomes after intracerebral hemorrhage. Eur J Neurosci 2015; 41:1381-91. [PMID: 25847406 PMCID: PMC4696550 DOI: 10.1111/ejn.12909] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/05/2015] [Accepted: 03/30/2015] [Indexed: 12/11/2022]
Abstract
Intracerebral hemorrhage (ICH) is a stroke subtype associated with high mortality and morbidity. Following ICH, excitotoxicity and inflammation significantly contribute to secondary brain injury and poor outcomes. Prostaglandin E2 (PGE2 ) levels rise locally with insult to the nervous system, and PGE2 is known to modulate these processes mainly through its E prostanoid (EP) receptors, EP1-4. EP receptor subtype 3 (EP3) is the most abundant EP receptor in the brain and we have previously shown that signaling through the PGE2 -EP3 axis exacerbates excitotoxicity and ischemic stroke outcomes. This study aimed to investigate the contribution of this pathway in modulating anatomical outcomes and functional recovery following ICH. Genetic deletion of EP3 resulted in 48.2 ± 7.3% less ICH-induced brain injury (P < 0.005) and improved functional recovery (P < 0.05), as identified by neurological deficit scoring. To start investigating the mechanisms involved in neuroprotection with impaired PGE2 -EP3 signaling, histological staining was performed to evaluate blood and ferric iron accumulation, neuroinflammation, blood-brain barrier dysfunction, and peripheral neutrophil infiltration. After ICH, EP3 knockout mice demonstrated 49.5 ± 8.8% and 42.8 ± 13.1% less blood (P < 0.01) and ferric iron (P < 0.05), respectively. Furthermore, EP3 knockout mice had significantly reduced astrogliosis, microglial activation, blood-brain barrier breakdown, and neutrophil infiltration. Collectively, these results suggest an injurious role for the PGE2 -EP3 signaling axis in modulating brain injury, inflammation, and neurological functional recovery after ICH. Modulation of the PGE2 -EP3 signaling axis may represent a putative therapeutic avenue for the treatment of ICH.
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Affiliation(s)
- Jenna L Leclerc
- Department of Anesthesiology, University of Florida, Gainesville, FL, USA
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Andrew S Lampert
- Department of Anesthesiology, University of Florida, Gainesville, FL, USA
| | - Matthew A Diller
- Department of Anesthesiology, University of Florida, Gainesville, FL, USA
| | - Sylvain Doré
- Department of Anesthesiology, University of Florida, Gainesville, FL, USA
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
- Departments of Neurology, Psychiatry, and Pharmaceutics, University of Florida, Gainesville, FL, USA
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Fu Y, Yang MS, Jiang J, Ganesh T, Joe E, Dingledine R. EP2 Receptor Signaling Regulates Microglia Death. Mol Pharmacol 2015; 88:161-70. [PMID: 25715797 DOI: 10.1124/mol.115.098202] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 02/20/2015] [Indexed: 11/22/2022] Open
Abstract
The timely resolution of inflammation prevents continued tissue damage after an initial insult. In the brain, the death of activated microglia by apoptosis has been proposed as one mechanism to resolve brain inflammation. How microglial death is regulated after activation is still unclear. We reported that exposure to lipopolysaccharide (LPS) and interleukin (IL)-13 together initially activates and then kills rat microglia in culture by a mechanism dependent on cyclooxygenase-2 (COX-2). We show here that activation of the E prostanoid receptor 2 (EP2, PTGER2) for prostaglandin E2 mediates microglial death induced by LPS/IL-13, and that EP2 activation by agonist alone kills microglia. Both EP2 antagonists and reactive oxygen scavengers block microglial death induced by either LPS/IL-13 or EP2 activation. By contrast, the homeostatic induction of heme oxygenase 1 (Hmox1) by LPS/IL-13 or EP2 activation protects microglia. Both the Hmox1 inducer cobalt protoporphyrin and a compound that releases the Hmox1 product carbon monoxide (CO) attenuated microglial death produced by LPS/IL-13. Whereas CO reduced COX-2 protein expression, EP2 activation increased Hmox1 and COX-2 expression at both the mRNA and protein level. Interestingly, caspase-1 inhibition prevented microglial death induced by either LPS/IL-13 or low (but not high) concentrations of butaprost, suggestive of a predominantly pyroptotic mode of death. Butaprost also caused the expression of activated caspase-3 in microglia, pointing to apoptosis. These results indicate that EP2 activation, which initially promotes microglial activation, later causes delayed death of activated microglia, potentially contributing to the resolution phase of neuroinflammation.
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Affiliation(s)
- Yujiao Fu
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (Y.F., M.-S.Y., J.J., T.G., R.D.); Neurology Department, Xiangya Hospital, Hunan, China (Y.F.); and Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea (M.-S.Y., E.J.)
| | - Myung-Soon Yang
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (Y.F., M.-S.Y., J.J., T.G., R.D.); Neurology Department, Xiangya Hospital, Hunan, China (Y.F.); and Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea (M.-S.Y., E.J.)
| | - Jianxiong Jiang
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (Y.F., M.-S.Y., J.J., T.G., R.D.); Neurology Department, Xiangya Hospital, Hunan, China (Y.F.); and Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea (M.-S.Y., E.J.)
| | - Thota Ganesh
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (Y.F., M.-S.Y., J.J., T.G., R.D.); Neurology Department, Xiangya Hospital, Hunan, China (Y.F.); and Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea (M.-S.Y., E.J.)
| | - Eunhye Joe
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (Y.F., M.-S.Y., J.J., T.G., R.D.); Neurology Department, Xiangya Hospital, Hunan, China (Y.F.); and Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea (M.-S.Y., E.J.)
| | - Raymond Dingledine
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (Y.F., M.-S.Y., J.J., T.G., R.D.); Neurology Department, Xiangya Hospital, Hunan, China (Y.F.); and Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea (M.-S.Y., E.J.)
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28
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Koch H, Caughie C, Elsen FP, Doi A, Garcia AJ, Zanella S, Ramirez JM. Prostaglandin E2 differentially modulates the central control of eupnoea, sighs and gasping in mice. J Physiol 2014; 593:305-19. [PMID: 25556802 DOI: 10.1113/jphysiol.2014.279794] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 09/24/2014] [Indexed: 01/10/2023] Open
Abstract
Prostaglandin E2 (PGE2) augments distinct inspiratory motor patterns, generated within the preBötzinger complex (preBötC), in a dose-dependent way. The frequency of sighs and gasping are stimulated at low concentrations, while the frequency of eupnoea increases only at high concentrations. We used in vivo microinjections into the preBötC and in vitro isolated brainstem slice preparations to investigate the dose-dependent effects of PGE2 on the preBötC activity. Synaptic measurements in whole cell voltage clamp recordings of inspiratory neurons revealed no changes in inhibitory or excitatory synaptic transmission in response to PGE2 exposure. In current clamp recordings obtained from inspiratory neurons of the preBötC, we found an increase in the frequency and amplitude of bursting activity in neurons with intrinsic bursting properties after exposure to PGE2. Riluzole, a blocker of the persistent sodium current, abolished the effect of PGE2 on sigh activity, while flufenamic acid, a blocker of the calcium-activated non-selective cation conductance, abolished the effect on eupnoeic activity caused by PGE2. Prostaglandins are important regulators of autonomic functions in the mammalian organism. Here we demonstrate in vivo that prostaglandin E2 (PGE2) can differentially increase the frequency of eupnoea (normal breathing) and sighs (augmented breaths) when injected into the preBötzinger complex (preBötC), a medullary area that is critical for breathing. Low concentrations of PGE2 (100-300 nm) increased the sigh frequency, while higher concentrations (1-2 μm) were required to increase the eupnoeic frequency. The concentration-dependent effects were similarly observed in the isolated preBötC. This in vitro preparation also revealed that riluzole, a blocker of the persistent sodium current (INap), abolished the modulatory effect on sighs, while flufenamic acid, an antagonist for the calcium-activated non-selective cation conductance (ICAN ) abolished the effect of PGE2 on fictive eupnoea at higher concentrations. At the cellular level PGE2 significantly increased the amplitude and frequency of intrinsic bursting in inspiratory neurons. By contrast PGE2 affected neither excitatory nor inhibitory synaptic transmission. We conclude that PGE2 differentially modulates sigh, gasping and eupnoeic activity by differentially increasing INap and ICAN currents in preBötC neurons.
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Affiliation(s)
- Henner Koch
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, 98101, USA; Department of Neurological Surgery, University of Washington, Seattle, WA, 98104, USA; Department of Neurology, University of Tübingen, Hertie Institute for Clinical Brain Research, Tübingen, Germany
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29
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Park TY, Baik EJ, Lee SH. Prostaglandin E₂-induced intercellular adhesion molecule-1 expression is mediated by cAMP/Epac signalling modules in bEnd.3 brain endothelial cells. Br J Pharmacol 2014; 169:604-18. [PMID: 23317035 DOI: 10.1111/bph.12103] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 12/21/2012] [Accepted: 12/26/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Prostaglandin E₂ (PGE₂) has been implicated in the regulation of adhesion molecules, leukocyte adhesion and infiltration into inflamed site. However, the underlying mechanism therein involved remains ill-defined. In this study, we explored its cellular mechanism of action in the regulation of the intercellular adhesion molecule-1 (ICAM-1) expression in the brain endothelial cells. EXPERIMENTAL APPROACH bEnd.3 cells, the murine cerebrovascular endothelial cell line and primary mouse brain endothelial cells were treated with PGE₂ with or without agonists/antagonists of PGE₂ receptors and associated signalling molecules. ICAM-1 expression, Akt phosphorylation and activity of NF-κB were determined by reverse transcription polymerase chain reaction (RT-PCR), immunoblot analysis, luciferase assay and immunocytochemistry. KEY RESULTS PGE₂ significantly up-regulated the expression of ICAM-1, which was blocked by EP4 antagonist (ONO-AE2-227) and knock-down of EP4. PGE₂ effects were mimicked by forskolin, dibutyryl cAMP (dbcAMP) and an exchange protein directly activated by cAMP (Epac) activator (8-Cpt-cAMP) but not a protein kinase A activator (N⁶-Bnz-cAMP). PGE₂-induced ICAM-1 expression was reduced by knock-down of Epac1. A PI3K specific inhibitor (LY294002), Akt inhibitor VIII (Akti) and NF-κB inhibitors (Bay-11-7082 and MG-132) attenuated the induction of ICAM-1 by PGE₂. PGE₂, dbcAMP and 8-Cpt-cAMP induced the phosphorylation of Akt, IκB kinase and IκBα and the translocation of p65 to the nucleus and increased NF-κB dependent reporter gene activity, which was diminished by Akti. CONCLUSION AND IMPLICATIONS Our findings suggest that PGE₂ induces ICAM-1 expression via EP4 receptor and Epac/Akt/NF-κB signalling pathway in bEnd.3 brain endothelial cells, supporting its pathophysiological role in brain inflammation.
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Affiliation(s)
- Tae Yeop Park
- Department of Physiology, School of Medicine, Ajou University, Suwon, Republic of Korea
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30
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Commentary on Kaushik et al.: Prostaglandin D2 is crucial for seizure suppression and postictal sleep. Novel evidence supporting a role for prostanoid receptors in seizure control. Exp Neurol 2014; 257:157-61. [DOI: 10.1016/j.expneurol.2014.05.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 04/26/2014] [Accepted: 05/02/2014] [Indexed: 11/22/2022]
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31
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Nagano T, Kimura SH, Takemura M. Prostaglandin E2 induces apoptosis in cultured rat microglia. Brain Res 2014; 1568:1-9. [PMID: 24845544 DOI: 10.1016/j.brainres.2014.05.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 03/05/2014] [Accepted: 05/10/2014] [Indexed: 12/15/2022]
Abstract
Prostaglandin E2 (PGE2) plays a critical role in the modulation of microglial function including migration and phagocytosis through EP2, which increases intracellular cyclic adenosine monophosphate (AMP) concentration. In the present study, we found that PGE2 reduces cell viability in microglia. PGE2 decreased 3-(4,5-dimethylthiazol-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) reduction and increased lactate dehydrogenase release, deoxyribonucleic acid fragmentation, and poly(ADP-ribose) polymerase cleavage after 24h incubation, suggesting that PGE2 induces apoptosis in these cells. An EP2 agonist, butaprost, and an EP4 agonist, PGE1 alcohol, also induced apoptosis, while an EP1 agonist, 17-phenyl trinor PGE2, or an EP3 agonist, sulprostone, at 10(-6)M did not. On the other hand, EP1-EP4 antagonists, SC-51322, AH6809, L-798106, or GW627368X, up to 10(-5)M did not affect the decrease in MTT reduction by PGE2. Intracellular cyclic AMP accumulation was induced by butaprost, but not 17-phenyl trinor PGE2, sulprostone, or PGE1 alcohol at 10(-6)M. Additionally, we previously reported that PGE2-induced intracellular cyclic AMP accumulation was reversed by AH6809. Besides EP receptors, one of other targets was thought to be prostaglandin transporter, but its inhibitors, bromocresol green or U-46619 up to 10(-5)M did not affect the decrease in MTT reduction by PGE2. These results suggest that PGE2 induces apoptosis in microglia independent of intracellular cyclic AMP concentration, and there are different mechanisms between PGE2-induced apoptosis and the modulation of microglial function.
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MESH Headings
- Alprostadil/analogs & derivatives
- Alprostadil/metabolism
- Animals
- Apoptosis/drug effects
- Apoptosis/physiology
- Blotting, Western
- Cell Survival/drug effects
- Cell Survival/physiology
- Cells, Cultured
- Cyclic AMP/metabolism
- DNA Fragmentation
- Dinoprostone/metabolism
- L-Lactate Dehydrogenase/metabolism
- Microglia/physiology
- Poly(ADP-ribose) Polymerases/metabolism
- Rats, Wistar
- Receptors, Prostaglandin E, EP1 Subtype/antagonists & inhibitors
- Receptors, Prostaglandin E, EP1 Subtype/metabolism
- Receptors, Prostaglandin E, EP2 Subtype/agonists
- Receptors, Prostaglandin E, EP2 Subtype/antagonists & inhibitors
- Receptors, Prostaglandin E, EP2 Subtype/metabolism
- Receptors, Prostaglandin E, EP3 Subtype/agonists
- Receptors, Prostaglandin E, EP3 Subtype/antagonists & inhibitors
- Receptors, Prostaglandin E, EP3 Subtype/metabolism
- Receptors, Prostaglandin E, EP4 Subtype/agonists
- Receptors, Prostaglandin E, EP4 Subtype/antagonists & inhibitors
- Receptors, Prostaglandin E, EP4 Subtype/metabolism
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Affiliation(s)
- Takayuki Nagano
- Department of Pharmacology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
| | - Shinya H Kimura
- Department of Pharmacology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
| | - Motohiko Takemura
- Department of Pharmacology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan.
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Suppression of inflammation with conditional deletion of the prostaglandin E2 EP2 receptor in macrophages and brain microglia. J Neurosci 2013; 33:16016-32. [PMID: 24089506 DOI: 10.1523/jneurosci.2203-13.2013] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Prostaglandin E2 (PGE2), a potent lipid signaling molecule, modulates inflammatory responses through activation of downstream G-protein coupled EP(1-4) receptors. Here, we investigated the cell-specific in vivo function of PGE2 signaling through its E-prostanoid 2 (EP2) receptor in murine innate immune responses systemically and in the CNS. In vivo, systemic administration of lipopolysaccharide (LPS) resulted in a broad induction of cytokines and chemokines in plasma that was significantly attenuated in EP2-deficient mice. Ex vivo stimulation of peritoneal macrophages with LPS elicited proinflammatory responses that were dependent on EP2 signaling and that overlapped with in vivo plasma findings, suggesting that myeloid-lineage EP2 signaling is a major effector of innate immune responses. Conditional deletion of the EP2 receptor in myeloid lineage cells in Cd11bCre;EP2(lox/lox) mice attenuated plasma inflammatory responses and transmission of systemic inflammation to the brain was inhibited, with decreased hippocampal inflammatory gene expression and cerebral cortical levels of IL-6. Conditional deletion of EP2 significantly blunted microglial and astrocytic inflammatory responses to the neurotoxin MPTP and reduced striatal dopamine turnover. Suppression of microglial EP2 signaling also increased numbers of dopaminergic (DA) neurons in the substantia nigra independent of MPTP treatment, suggesting that microglial EP2 may influence development or survival of DA neurons. Unbiased microarray analysis of microglia isolated from adult Cd11bCre;EP2(lox/lox) and control mice demonstrated a broad downregulation of inflammatory pathways with ablation of microglial EP2 receptor. Together, these data identify a cell-specific proinflammatory role for macrophage/microglial EP2 signaling in innate immune responses systemically and in brain.
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Xia T, Ni S, Li X, Yao J, Qi H, Fan X, Wang J. Sustained delivery of dbcAMP by poly(propylene carbonate) micron fibers promotes axonal regenerative sprouting and functional recovery after spinal cord hemisection. Brain Res 2013; 1538:41-50. [PMID: 24076153 DOI: 10.1016/j.brainres.2013.09.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Revised: 09/14/2013] [Accepted: 09/19/2013] [Indexed: 01/25/2023]
Abstract
This study describes the use of poly(propylene carbonate) (PPC) electrospun fibers as vehicle for the sustained delivery of dibutyryl cyclic adenosine monophosphate (dbcAMP) to the hemisected spinal cord. The dbcAMP and PPC were uniformly mixed with acetonitrile; then, electrospinning was used to generate micron fibers. The release of dbcAMP was assessed by ELISA in vitro. Our results showed that the encapsulation of dbcAMP in the fibers led to stable and prolonged release in vitro. The PPC micron fibers containing dbcAMP and the PPC micron fibers without dbcAMP were then implanted into the hemisected thoracic spinal cord, followed by testing of the functional recovery and immunohistochemistry. Compared with the control group, sustained delivery of dbcAMP promoted axonal regenerative sprouting and functional recovery and reduced glial scar formation, and the PPC micron fibers without dbcAMP did not have these effects. Our findings demonstrated the feasibility of using PPC electrospun fibers containing dbcAMP for spinal cord injury. The approach described here also will provide a platform for the potential delivery of other axon-growth-promoting or scar-inhibiting agents.
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Affiliation(s)
- Tongliang Xia
- Department of Neurosurgery, Qilu Hospital, Shandong University, 107# Wenhua Xi Road, Jinan 250012, PR China
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Zhang J, Niu N, Li B, McNutt MA. Neuron-derived IgG protects neurons from complement-dependent cytotoxicity. J Histochem Cytochem 2013; 61:869-79. [PMID: 23979841 DOI: 10.1369/0022155413504196] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Passive immunity of the nervous system has traditionally been thought to be predominantly due to the blood-brain barrier. This concept must now be revisited based on the existence of neuron-derived IgG. The conventional concept is that IgG is produced solely by mature B lymphocytes, but it has now been found to be synthesized by murine and human neurons. However, the function of this endogenous IgG is poorly understood. In this study, we confirm IgG production by rat cortical neurons at the protein and mRNA levels, with 69.0 ± 5.8% of cortical neurons IgG-positive. Injury to primary-culture neurons was induced by complement leading to increases in IgG production. Blockage of neuron-derived IgG resulted in more neuronal death and early apoptosis in the presence of complement. In addition, FcγRI was found in microglia and astrocytes. Expression of FcγR I in microglia was increased by exposure to neuron-derived IgG. Release of NO from microglia triggered by complement was attenuated by neuron-derived IgG, and this attenuation could be reversed by IgG neutralization. These data demonstrate that neuron-derived IgG is protective of neurons against injury induced by complement and microglial activation. IgG appears to play an important role in maintaining the stability of the nervous system.
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Zhang J, Niu N, Wang M, McNutt MA, Zhang D, Zhang B, Lu S, Liu Y, Liu Z. Neuron-derived IgG protects dopaminergic neurons from insult by 6-OHDA and activates microglia through the FcγR I and TLR4 pathways. Int J Biochem Cell Biol 2013; 45:1911-20. [PMID: 23791745 DOI: 10.1016/j.biocel.2013.06.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 05/24/2013] [Accepted: 06/03/2013] [Indexed: 12/09/2022]
Abstract
Oxidative and immune attacks from the environment or microglia have been implicated in the loss of dopaminergic neurons of Parkinson's disease. The role of IgG which is an important immunologic molecule in the process of Parkinson's disease has been unclear. Evidence suggests that IgG can be produced by neurons in addition to its traditionally recognized source B lymphocytes, but its function in neurons is poorly understood. In this study, extensive expression of neuron-derived IgG was demonstrated in dopaminergic neurons of human and rat mesencephalon. With an in vitro Parkinson's disease model, we found that neuron-derived IgG can improve the survival and reduce apoptosis of dopaminergic neurons induced by 6-hydroxydopamine toxicity, and also depress the release of NO from microglia triggered by 6-hydroxydopamine. Expression of TNF-α and IL-10 in microglia was elevated to protective levels by neuron-derived IgG at a physiologic level via the FcγR I and TLR4 pathways and microglial activation could be attenuated by IgG blocking. All these data suggested that neuron-derived IgG may exert a self-protective function by activating microglia properly, and IgG may be involved in maintaining immunity homeostasis in the central nervous system and serve as an active factor under pathological conditions such as Parkinson's disease.
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Affiliation(s)
- Jie Zhang
- Department of Human Anatomy, Weifang Medical University, Weifang 261053, China
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Quan Y, Jiang J, Dingledine R. EP2 receptor signaling pathways regulate classical activation of microglia. J Biol Chem 2013; 288:9293-302. [PMID: 23404506 DOI: 10.1074/jbc.m113.455816] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activation of EP2 receptors by prostaglandin E2 (PGE2) promotes brain inflammation in neurodegenerative diseases, but the pathways responsible are unclear. EP2 receptors couple to Gαs and increase cAMP, which associates with protein kinase A (PKA) and cAMP-regulated guanine nucleotide exchange factors (Epacs). Here, we studied EP2 function and its signaling pathways in rat microglia in their resting state or undergoing classical activation in vitro following treatment with low concentrations of lipopolysaccharide and interferon-γ. Real time PCR showed that PGE2 had no effect on expression of CXCL10, TGF-β1, and IL-11 and exacerbated the rapid up-regulation of mRNAs encoding cyclooxygenase-2, inducible NOS, IL-6, and IL-1β but blunted the production of mRNAs encoding TNF-α, IL-10, CCL3, and CCL4. These effects were mimicked fully by the EP2 agonist butaprost but only weakly by the EP1/EP3 agonist 17-phenyl trinor PGE2 or the EP4 agonist CAY10598 and not at all by the EP3/EP1 agonist sulprostone and confirmed by protein measurements of cyclooxygenase-2, IL-6, IL-10, and TNF-α. In resting microglia, butaprost induced cAMP formation and altered the mRNA expression of inflammatory mediators, but protein expression was unchanged. The PKA inhibitor H89 had little or no effect on inflammatory mediators modulated by EP2, whereas the Epac activator 8-(4-chlorophenylthio)-2'-O-methyladenosine 3',5'-cyclic monophosphate acetoxymethyl ester mimicked all butaprost effects. These results indicate that EP2 activation plays a complex immune regulatory role during classical activation of microglia and that Epac pathways are prominent in this role.
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Affiliation(s)
- Yi Quan
- Department of Pharmacology, Emory University, Atlanta, GA 30322, USA
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Brawek B, Garaschuk O. Microglial calcium signaling in the adult, aged and diseased brain. Cell Calcium 2013; 53:159-69. [PMID: 23395344 DOI: 10.1016/j.ceca.2012.12.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 12/10/2012] [Indexed: 10/27/2022]
Abstract
Microglial cells are the resident immune cells of the CNS. They mediate innate immune response of the brain to injury, inflammation and neurodegenerative diseases. Apart from their role in disease they are critically involved in the development and plasticity-driven reorganization of neuronal networks and the homeostatic maintenance of brain tissue. Accumulating in vitro evidence suggests that executive functions of microglia are coupled to the intracellular Ca(2+) signaling of these cells. So far, however, very little is known about microglial Ca(2+) signaling in situ or in vivo, both in the healthy and in the diseased brain. Here, we summarize the recent in vivo/in situ findings and compare the properties of surveillant microglia in these preparations with those of microglia in vitro. The data suggest that surveillant microglia rarely show spontaneous Ca(2+) transients, express fewer functional receptors directly coupled to changes in the intracellular free Ca(2+) concentration on their surface, but vividly respond with Ca(2+) transients to cell or tissue damage in their microenvironment. Interestingly, some of these properties microglia share with monocytes engrafting in the brain under pathological conditions.
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Affiliation(s)
- Bianca Brawek
- Institute of Physiology II, Eberhard Karls University of Tuebingen, Keplerstr. 15, 72074 Tuebingen, Germany
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Mohan S, Ahmad AS, Glushakov AV, Chambers C, Doré S. Putative role of prostaglandin receptor in intracerebral hemorrhage. Front Neurol 2012; 3:145. [PMID: 23097645 PMCID: PMC3477820 DOI: 10.3389/fneur.2012.00145] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 09/30/2012] [Indexed: 01/21/2023] Open
Abstract
Each year, approximately 795,000 people experience a new or recurrent stroke. Of all strokes, 84% are ischemic, 13% are intracerebral hemorrhage (ICH) strokes, and 3% are subarachnoid hemorrhage strokes. Despite the decreased incidence of ischemic stroke, there has been no change in the incidence of hemorrhagic stroke in the last decade. ICH is a devastating disease 37–38% of patients between the ages of 45 and 64 die within 30 days. In an effort to prevent ischemic and hemorrhagic strokes we and others have been studying the role of prostaglandins and their receptors. Prostaglandins are bioactive lipids derived from the metabolism of arachidonic acid. They sustain homeostatic functions and mediate pathogenic mechanisms, including the inflammatory response. Most prostaglandins are produced from specific enzymes and act upon cells via distinct G-protein coupled receptors. The presence of multiple prostaglandin receptors cross-reactivity and coupling to different signal transduction pathways allow differentiated cells to respond to prostaglandins in a unique manner. Due to the number of prostaglandin receptors, prostaglandin-dependent signaling can function either to promote neuronal survival or injury following acute excitotoxicity, hypoxia, and stress induced by ICH. To better understand the mechanisms of neuronal survival and neurotoxicity mediated by prostaglandin receptors, it is essential to understand downstream signaling. Several groups including ours have discovered unique roles for prostaglandin receptors in rodent models of ischemic stroke, excitotoxicity, and Alzheimer disease, highlighting the emerging role of prostaglandin receptor signaling in hemorrhagic stroke with a focus on cyclic-adenosine monophosphate and calcium (Ca2+) signaling. We review current ICH data and discuss future directions notably on prostaglandin receptors, which may lead to the development of unique therapeutic targets against hemorrhagic stroke and brain injuries alike.
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Affiliation(s)
- Shekher Mohan
- Department of Anesthesiology, College of Medicine, University of Florida Gainesville, FL, USA
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Abstract
Pro-inflammatory stimuli evoke an export of glutamate from microglia that is sufficient to contribute to excitotoxicity in neighbouring neurons. Since microglia also express various glutamate receptors themselves, we were interested in the potential feedback of glutamate on this system. Several agonists of mGluRs (metabotropic glutamate receptors) were applied to primary rat microglia, and the export of glutamate into their culture medium was evoked by LPS (lipopolysaccharide). Agonists of group-II and -III mGluR ACPD [(1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid] and L-AP4 [L-(+)-2-amino-4-phosphonobutyric acid] were both capable of completely blocking the glutamate export without interfering with the production of NO (nitric oxide); the group-I agonist tADA (trans-azetidine-2,4-dicarboxylic acid) was ineffective. Consistent with the possibility of feedback, inhibition of mGluR by MSPG [(R,S)-α-2-methyl-4sulfonophenylglycine] potentiated glutamate export. As the group-II and -III mGluR are coupled to Gαi-containing G-proteins and the inhibition of adenylate cyclase, we explored the role of cAMP in this effect. Inhibition of cAMP-dependent protein kinase [also known as protein kinase A (PKA)] by H89 mimicked the effect of ACPD, and the mGluR agonist had its actions reversed by artificially sustaining cAMP through the PDE (phosphodiesterase) inhibitor IBMX (isobutylmethylxanthine) or the cAMP mimetic dbcAMP (dibutyryl cAMP). These data indicate that mGluR activation attenuates a potentially neurotoxic export of glutamate from activated microglia and implicate cAMP as a contributor to this aspect of microglial action.
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Ghosh M, Garcia-Castillo D, Aguirre V, Golshani R, Atkins CM, Bramlett HM, Dietrich WD, Pearse DD. Proinflammatory cytokine regulation of cyclic AMP-phosphodiesterase 4 signaling in microglia in vitro and following CNS injury. Glia 2012; 60:1839-59. [PMID: 22865690 DOI: 10.1002/glia.22401] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2011] [Accepted: 07/09/2012] [Indexed: 01/15/2023]
Abstract
Cyclic AMP suppresses immune cell activation and inflammation. The positive feedback loop of proinflammatory cytokine production and immune activation implies that cytokines may not only be regulated by cyclic AMP but also conversely regulate cyclic AMP. This study examined the effects of tumor necrosis factor (TNF)-α and interleukin (IL)-1β on cyclic AMP-phosphodiesterase (PDE) signaling in microglia in vitro and after spinal cord injury (SCI) or traumatic brain injury (TBI). TNF-α or IL-1β stimulation produced a profound reduction (>90%) of cyclic AMP within EOC2 microglia from 30 min that then recovered after IL-1β but remained suppressed with TNF-α through 24 h. Cyclic AMP was also reduced in TNF-α-stimulated primary microglia, albeit to a lesser extent. Accompanying TNF-α-induced cyclic AMP reductions, but not IL-1β, was increased cyclic AMP-PDE activity. The role of PDE4 activity in cyclic AMP reductions was confirmed by using Rolipram. Examination of pde4 mRNA revealed an immediate, persistent increase in pde4b with TNF-α; IL-1β increased all pde4 mRNAs. Immunoblotting for PDE4 showed that both cytokines increased PDE4A1, but only TNF-α increased PDE4B2. Immunocytochemistry revealed PDE4B nuclear translocation with TNF-α but not IL-1β. Acutely after SCI/TBI, where cyclic AMP levels are reduced, PDE4B was localized to activated OX-42(+) microglia; PDE4B was absent in OX-42(+) cells in uninjured spinal cord/cortex or inactive microglia. Immunoblotting showed PDE4B2 up-regulation from 24 h to 1 wk post-SCI, the peak of microglia activation. These studies show that TNF-α and IL-1β differentially affect cyclic AMP-PDE signaling in microglia. Targeting PDE4B2 may be a putative therapeutic direction for reducing microglia activation in CNS injury and neurodegenerative diseases.
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Affiliation(s)
- Mousumi Ghosh
- The Miami Project to Cure Paralysis, The University of Miami Miller School of Medicine, Miami, Florida 33101, USA
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Lima IVDA, Bastos LFS, Limborço-Filho M, Fiebich BL, de Oliveira ACP. Role of prostaglandins in neuroinflammatory and neurodegenerative diseases. Mediators Inflamm 2012; 2012:946813. [PMID: 22778499 PMCID: PMC3385693 DOI: 10.1155/2012/946813] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 04/05/2012] [Indexed: 11/17/2022] Open
Abstract
Increasing data demonstrates that inflammation participates in the pathophysiology of neurodegenerative diseases. Among the different inflammatory mediators involved, prostaglandins play an important role. The effects induced by prostaglandins might be mediated by activation of their known receptors or by nonclassical mechanisms. In the present paper, we discuss the evidences that link prostaglandins, as well as the enzymes that produce them, to some neurological diseases.
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Affiliation(s)
- Isabel Vieira de Assis Lima
- Department of Pharmacology, Federal University of Minas Gerais, Avenida Antonio Carlos, 6627, 31270-901 Belo Horizonte, MG, Brazil
| | - Leandro Francisco Silva Bastos
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Avenida Antonio Carlos, 6627, 31270-901 Belo Horizonte, Brazil
- Department of Psychology and Neuroscience, Muenzinger Building, Colorado University of Colorado Boulder, Avenida, Boulder, CO 80309-0354, USA
| | - Marcelo Limborço-Filho
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Avenida Antonio Carlos, 6627, 31270-901 Belo Horizonte, Brazil
| | - Bernd L. Fiebich
- Department of Psychiatry and Psychotherapy, University of Freiburg Medical School, Hauptstraße 5, 79104 Freiburg, Germany
- VivaCell Biotechnology GmbH, Ferdinand-Porsche-Straße 5, 79211 Denzlingen, Germany
| | - Antonio Carlos Pinheiro de Oliveira
- Department of Pharmacology, Federal University of Minas Gerais, Avenida Antonio Carlos, 6627, 31270-901 Belo Horizonte, MG, Brazil
- Department of Psychiatry and Psychotherapy, University of Freiburg Medical School, Hauptstraße 5, 79104 Freiburg, Germany
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Phosphodiesterase inhibitors control A172 human glioblastoma cell death through cAMP-mediated activation of protein kinase A and Epac1/Rap1 pathways. Life Sci 2011; 90:373-80. [PMID: 22227470 DOI: 10.1016/j.lfs.2011.12.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 11/22/2011] [Accepted: 12/13/2011] [Indexed: 11/22/2022]
Abstract
AIMS We investigated whether cAMP-mediated protein kinase A(PKA) and Epac1/Rap1 pathways differentially affect brain tumor cell death using 4-(3-cyclopentyloxy-4-methoxyphenyl)-2-pyrrolidone(rolipram), specific phosphodiesterase type IV(PDE IV) inhibitor. MAIN METHODS A172 and U87MG human glioblastoma cells were used. Percentage of cell survival was determined by MTT assay. PKA and Epac1/Rap1 activation was determined by western blotting and pull-down assay, respectively. Cell cycle and hypodiploid cell formation were assessed by flow cytometry analysis. KEY FINDINGS Non-specific PDE inhibitors, isobutylmethylxanthine(IBMX) and theophylline reduce survival percentage of A172 and U87MG cells. The expression of PDE4A and PDE4B was detected in A172 and U87MG cells. Rolipram-treated A172 or U87MG cell survival was lower in the presence of forskolin, adenylate cyclase activator, than that in its absence. Co-treatment with rolipram and forskolin also enhanced CREB phosphorylation on serine 133 that was inhibited by H-89, PKA inhibitor and cAMP-responsive guanine nucleotide exchange factor 1(Epac1), a Rap GDP exchange factor-mediated Rap1 activity in A172 cells. When A172 cells were treated with cell-permeable dibutyryl-cAMP(dbcAMP), PKA activator or 8-(4-chloro-phenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate(CPT), Epac1 activator, basal level of cell death was increased and cell cycle was arrested at the phase of G2/M. Rolipram-induced A172 cell death was also increased by the co-treatment with dbcAMP or CPT, but it was inhibited by the pre-treatment with H-89. SIGNIFICANCE These findings demonstrate that PKA and Epac1/Rap1 pathways could cooperatively play a role in rolipram-induced brain tumor cell death. It suggests that rolipram might regulate glioblastoma cell density through dual pathways of PKA- and Epac1/Rap1-mediated cell death and cell cycle arrest.
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Segi-Nishida E. Exploration of new molecular mechanisms for antidepressant actions of electroconvulsive seizure. Biol Pharm Bull 2011; 34:939-44. [PMID: 21719995 DOI: 10.1248/bpb.34.939] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Electroconvulsive seizure (ECS) therapy is a clinically proven treatment for depression and is often effective even in patients resistant to chemical antidepressants. However, the molecular mechanisms underlying the therapeutic efficacy of ECS are not fully understood. Here, I review studies that show molecular, cellular, and behavioral changes by ECS treatment, and discuss the functions of ECS to underlie the action of antidepressant effects. In hippocampus, these changes cover gene induction, increased adult neurogenesis, and electrophysiological reactivity. Especially, the role of vascular endothelial growth factor (VEGF) in neurogenesis is discussed. Among other gene expression changes in hippocampus, a role of cyclooxygenase (COX)-2, an inducible type of the rate-limiting enzyme of prostanoid synthesis, is focused. ECS-induced changes in other brain regions such as prefrontal cortex and hypothalamus, and ECS-induced behavioral changes are also reviewed. Understanding the molecular, cellular, and behavioral changes by ECS will provide a new view to find potential targets for novel antidepressant design that are highlighted by these findings.
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Affiliation(s)
- Eri Segi-Nishida
- Department of Systems Bioscience for Drug Discovery, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606–8501, Japan.
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Smith WL, Urade Y, Jakobsson PJ. Enzymes of the cyclooxygenase pathways of prostanoid biosynthesis. Chem Rev 2011; 111:5821-65. [PMID: 21942677 PMCID: PMC3285496 DOI: 10.1021/cr2002992] [Citation(s) in RCA: 342] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- William L Smith
- Department of Biological Chemistry, University of Michigan Medical School, 1150 West Medical Center Drive, 5301 MSRB III, Ann Arbor, Michigan 48109-5606, USA.
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Toll-like receptor 4-mediated cAMP production up-regulates B-cell activating factor expression in Raw264.7 macrophages. Exp Cell Res 2011; 317:2447-55. [PMID: 21782812 DOI: 10.1016/j.yexcr.2011.07.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 06/18/2011] [Accepted: 07/05/2011] [Indexed: 11/22/2022]
Abstract
B-cell activating factor (BAFF) plays a role in the generation and the maintenance of mature B cells. Lipopolysaccharide (LPS) increased BAFF expression through the activation of toll-like receptor 4 (TLR4)-dependent signal transduction. Here, we investigated the mechanism of action on mouse BAFF (mBAFF) expression by cAMP production in Raw264.7 mouse macrophages. mBAFF expression was increased by the treatment with a cAMP analogue, dibutyryl-cAMP which is the activator of protein kinase A (PKA), cAMP effector protein. PKA activation was measured by the phosphorylation of cAMP-response element binding protein (CREB) on serine 133 (S133). cAMP production and CREB (S133) phosphorylation were augmented by LPS-stimulation. While mBAFF promoter activity was enhanced by the co-transfection with pS6-RSV-CREB, it was reduced by siRNA-CREB. PKA inhibitor, H-89, reduced CREB (S133) phosphorylation and mBAFF expression in control and LPS-stimulated macrophages. Another principal cAMP effector protein is cAMP-responsive guanine nucleotide exchange factor (Epac), a Rap GDP exchange factor. Epac was activated by the treatment with 8-(4-chloro-phenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate (CPT), Epac activator, as judged by the measurement of Rap1 activation. Basal level of mBAFF expression was increased by CPT treatment. LPS-stimulated mBAFF expression was also slightly enhanced by co-treatment with CPT. In addition, dibutyryl-cAMP and CPT enhanced mBAFF expression in bone marrow-derived macrophages (BMDM). With these data, it suggests that the activation of PKA and cAMP/Epac1/Rap1 pathways could be required for basal mBAFF expression, as well as being up-regulated in the TLR4-induced mBAFF expression.
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Ng KY, Wong YH, Wise H. Glial cells isolated from dorsal root ganglia express prostaglandin E2 (EP4) and prostacyclin (IP) receptors. Eur J Pharmacol 2011; 661:42-8. [DOI: 10.1016/j.ejphar.2011.04.040] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 04/04/2011] [Accepted: 04/14/2011] [Indexed: 01/31/2023]
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Beta-adrenergic stimulation suppresses phagocytosis via Epac activation in murine microglial cells. Brain Res 2011; 1407:1-12. [PMID: 21763641 DOI: 10.1016/j.brainres.2011.06.050] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 06/21/2011] [Indexed: 01/18/2023]
Abstract
Endogenous noradrenaline presumably prohibits neuroinflammation by stimulation of β-adrenergic receptor-dependent suppression of the production of inflammatory mediators. Using the microglial cell line, BV-2, as well as primary murine microglial cells, we show here that the β-adrenergic agonist, isoproterenol, suppresses uptake of hydrophobic polystyrene microspheres. The number of cells showing a specific number of engulfed microspheres followed a Poisson distribution. Isoproterenol decreased the number of engulfed particles per cell and the number of cells showing at least one incorporated particle. Elevation of intracellular cAMP by activation of adenylyl cyclase activity with forskolin, suppression of phosphodiesterase activity with 3-isobutyl-1-methylxanthine (IBMX), or application of the membrane-permeable cAMP analog, 8-bromo-cAMP, suppressed particle uptake. The protein kinase A inhibitor, H-89, did not prevent isoproterenol-dependent suppression of particle engulfment. However, activation of exchange protein activated by cAMP (Epac), specific guanine nucleotide exchange factors for the Ras GTPase homologues, Rap1 and Rap2, with the Epac1-specific cAMP analog, 8-pCPT-2'-O-Me-cAMP, mimicked the suppressive effect of isoproterenol on particle uptake. Our results suggest that β-adrenergic receptor stimulation suppresses particle uptake in microglia by cAMP-dependent activation of Epac.
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Abstract
Prostaglandins are lipid autacoids derived from arachidonic acid. They both sustain homeostatic functions and mediate pathogenic mechanisms, including the inflammatory response. They are generated from arachidonate by the action of cyclooxygenase isoenzymes, and their biosynthesis is blocked by nonsteroidal antiinflammatory drugs, including those selective for inhibition of cyclooxygenase-2. Despite the clinical efficacy of nonsteroidal antiinflammatory drugs, prostaglandins may function in both the promotion and resolution of inflammation. This review summarizes insights into the mechanisms of prostaglandin generation and the roles of individual mediators and their receptors in modulating the inflammatory response. Prostaglandin biology has potential clinical relevance for atherosclerosis, the response to vascular injury and aortic aneurysm.
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Affiliation(s)
- Emanuela Ricciotti
- Institute for Translational Medicine and Therapeutics, 153 Johnson Pavilion, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Moon EY, Lee JH, Lee JW, Song JH, Pyo S. ROS/Epac1-mediated Rap1/NF-kappaB activation is required for the expression of BAFF in Raw264.7 murine macrophages. Cell Signal 2011; 23:1479-88. [PMID: 21596132 DOI: 10.1016/j.cellsig.2011.05.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 04/27/2011] [Accepted: 05/02/2011] [Indexed: 11/26/2022]
Abstract
B-cell activating factor (BAFF) plays a role for the maturation and the maintenance of B cells. Lipopolysaccharide (LPS) activates toll-like receptor 4 (TLR4)-dependent signal transduction, which resulted in BAFF expression through nuclear factor kappa B (NF-κB) activation. Here, we investigated whether BAFF expression could be regulated by p65 phosphorylation through the production of reactive oxygen species (ROS) or cyclic AMP (cAMP) in Raw264.7 murine macrophages. mBAFF expression was reduced by ROS scavengers and it was increased by dibutyl-cAMP, a cAMP analogue. mBAFF expression and mBAFF promoter activity were increased by co-transfection of p65 but they were reduced by p65-small interference (si) RNA. Serine (Ser) 276 phosphorylation of p65 was increased by LPS-mediated PKA activation or by the treatment with forskolin, adenylate cyclase activator and dibutyl-cAMP. In contrast, p65 phosphorylation at Ser276 was decreased by ROS scavengers. H(2)O(2) increased intracellular cAMP concentration, significantly. While no increase in p65 phosphorylation at Ser276 was detected by the treatment with H(2)O(2), CREB and p65 phosphorylation at Ser133 and Ser536 was observed, respectively. It implicates that p65 phosphorylation at Ser276 is independent of ROS-induced cAMP production. As another cAMP effector protein was cAMP-responsive guanine nucleotide exchange factor (Epac), a Rap GDP exchange factor, NF-κB was activated by the treatment with 8-(4-chloro-phenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate (CPT) that is an activator to Epac. Epac1-mediated Rap1 was activated by the treatment with H(2)O(2) but it was inhibited by ROS scavengers. CPT induced p65 phosphorylation at both Ser276 and Ser536. CPT also increased not only mBAFF expression but mBAFF promoter activity. Data demonstrate that TLR4-mediated mBAFF expression was resulted from the crosstalk of p65 phosphorylation at Ser536 and Ser276 through ROS- and/or cAMP-mediated signal transduction. It suggests for the first time that ROS/Epac1-mediated Rap1/NF-κB pathway could be required for BAFF expression.
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Affiliation(s)
- Eun-Yi Moon
- Department of Bioscience and Biotechnology, Sejong University, Seoul 143-747, Republic of Korea.
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Hubbard LLN, Wilke CA, White ES, Moore BB. PTEN limits alveolar macrophage function against Pseudomonas aeruginosa after bone marrow transplantation. Am J Respir Cell Mol Biol 2011; 45:1050-8. [PMID: 21527775 DOI: 10.1165/rcmb.2011-0079oc] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Hematopoietic stem cell transplant patients are susceptible to infection despite cellular reconstitution. In a murine model of syngeneic bone marrow transplantation (BMT), we previously reported that BMT mice have impaired host defense against Pseudomonas aeruginosa pneumonia due to overproduction of (PG)E(2) in lung. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is an effector in the PGE(2) signaling pathway that negatively regulates alveolar macrophage (AM) phagocytosis and bacterial killing. Therefore, examined whether overproduction of PGE(2) after BMT inhibits AM host defense by up-regulating PTEN phosphatase activity. We found that PTEN activity is elevated in BMT AMs in response to increased PGE(2) signaling and that pharmacological inhibition of PTEN activity in BMT AMs fully restores phagocytosis of serum-opsonized P. aeruginosa but only partially restores phagocytosis of nonopsonized P. aeruginosa. In wild-type mice transplanted with myeloid-specific conditional PTEN knockout (PTEN CKO) bone marrow, bacterial clearance is improved after challenge with P. aeruginosa pneumonia. Furthermore, PTEN CKO BMT AMs display improved TNF-α production and enhanced phagocytosis and killing of serum-opsonized P. aeruginosa despite overproduction of PGE(2). However, AM phagocytosis of nonopsonized P. aeruginosa is only partially restored in the absence of PTEN after BMT. This may be related to elevated AM expression of IL-1 receptor-associated kinase (IRAK)-M, a molecule previously identified in the PGE(2) signaling pathway to inhibit AM phagocytosis of nonopsonized bacteria. These data suggest that PGE(2) signaling up-regulates IRAK-M independently of PTEN and that these molecules differentially inhibit opsonized and nonopsonized phagocytosis of P. aeruginosa.
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Affiliation(s)
- Leah L N Hubbard
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, USA.
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