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Lee PR, Johnson TP, Gnanapavan S, Giovannoni G, Wang T, Steiner JP, Medynets M, Vaal MJ, Gartner V, Nath A. Protease-activated receptor-1 activation by granzyme B causes neurotoxicity that is augmented by interleukin-1β. J Neuroinflammation 2017; 14:131. [PMID: 28655310 PMCID: PMC5488439 DOI: 10.1186/s12974-017-0901-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 06/14/2017] [Indexed: 12/05/2022] Open
Abstract
Background The cause of neurodegeneration in progressive forms of multiple sclerosis is unknown. We investigated the impact of specific neuroinflammatory markers on human neurons to identify potential therapeutic targets for neuroprotection against chronic inflammation. Methods Surface immunocytochemistry directly visualized protease-activated receptor-1 (PAR1) and interleukin-1 (IL-1) receptors on neurons in human postmortem cortex in patients with and without neuroinflammatory lesions. Viability of cultured neurons was determined after exposure to cerebrospinal fluid from patients with progressive multiple sclerosis or purified granzyme B and IL-1β. Inhibitors of PAR1 activation and of PAR1-associated second messenger signaling were used to elucidate a mechanism of neurotoxicity. Results Immunohistochemistry of human post-mortem brain tissue demonstrated cells expressing higher amounts of PAR1 near and within subcortical lesions in patients with multiple sclerosis compared to control tissue. Human cerebrospinal fluid samples containing granzyme B and IL-1β were toxic to human neuronal cultures. Granzyme B was neurotoxic through activation of PAR1 and subsequently the phospholipase Cβ-IP3 second messenger system. Inhibition of PAR1 or IP3 prevented granzyme B toxicity. IL-1β enhanced granzyme B-mediated neurotoxicity by increasing PAR1 expression. Conclusions Neurons within the inflamed central nervous system are imperiled because they express more PAR1 and are exposed to a neurotoxic combination of both granzyme B and IL-1β. The effects of these inflammatory mediators may be a contributing factor in the progressive brain atrophy associated with neuroinflammatory diseases. Knowledge of how exposure to IL-1β and granzyme B act synergistically to cause neuronal death yields potential novel neuroprotective treatments for neuroinflammatory diseases.
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Affiliation(s)
- Paul R Lee
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive, Building 10, Room CRC 3-2563, Bethesda, MD, 20892, USA.
| | - Tory P Johnson
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive, Building 10, Room CRC 3-2563, Bethesda, MD, 20892, USA
| | - Sharmilee Gnanapavan
- Centre for Neuroscience and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, London, UK
| | - Gavin Giovannoni
- Centre for Neuroscience and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, London, UK
| | - Tongguang Wang
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive, Building 10, Room CRC 3-2563, Bethesda, MD, 20892, USA
| | - Joseph P Steiner
- Translational Neuroscience Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Marie Medynets
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive, Building 10, Room CRC 3-2563, Bethesda, MD, 20892, USA
| | - Mark J Vaal
- Translational Neuroscience Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Valerie Gartner
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Avindra Nath
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive, Building 10, Room CRC 3-2563, Bethesda, MD, 20892, USA
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52
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Bushi D, Stein ES, Golderman V, Feingold E, Gera O, Chapman J, Tanne D. A Linear Temporal Increase in Thrombin Activity and Loss of Its Receptor in Mouse Brain following Ischemic Stroke. Front Neurol 2017; 8:138. [PMID: 28443061 PMCID: PMC5385331 DOI: 10.3389/fneur.2017.00138] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/24/2017] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Brain thrombin activity is increased following acute ischemic stroke and may play a pathogenic role through the protease-activated receptor 1 (PAR1). In order to better assess these factors, we obtained a novel detailed temporal and spatial profile of thrombin activity in a mouse model of permanent middle cerebral artery occlusion (pMCAo). METHODS Thrombin activity was measured by fluorescence spectroscopy on coronal slices taken from the ipsilateral and contralateral hemispheres 2, 5, and 24 h following pMCAo (n = 5, 6, 5 mice, respectively). Its spatial distribution was determined by punch samples taken from the ischemic core and penumbra and further confirmed using an enzyme histochemistry technique (n = 4). Levels of PAR1 were determined using western blot. RESULTS Two hours following pMCAo, thrombin activity in the stroke core was already significantly higher than the contralateral area (11 ± 5 vs. 2 ± 1 mU/ml). At 5 and 24 h, thrombin activity continued to rise linearly (r = 0.998, p = 0.001) and to expand in the ischemic hemisphere beyond the ischemic core reaching deleterious levels of 271 ± 117 and 123 ± 14 mU/ml (mean ± SEM) in the basal ganglia and ischemic cortex, respectively. The peak elevation of thrombin activity in the ischemic core that was confirmed by fluorescence histochemistry was in good correlation with the infarcts areas. PAR1 levels in the ischemic core decreased as stroke progressed and thrombin activity increased. CONCLUSION In conclusion, there is a time- and space-related increase in brain thrombin activity in acute ischemic stroke that is closely related to the progression of brain damage. These results may be useful in the development of therapeutic strategies for ischemic stroke that involve the thrombin-PAR1 pathway in order to prevent secondary thrombin related brain damage.
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Affiliation(s)
- Doron Bushi
- Comprehensive Stroke Center, Department of Neurology, The J. Sagol Neuroscience Center, Chaim Sheba Medical Center, Tel HaShomer, Israel.,Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Efrat Shavit Stein
- Comprehensive Stroke Center, Department of Neurology, The J. Sagol Neuroscience Center, Chaim Sheba Medical Center, Tel HaShomer, Israel
| | - Valery Golderman
- Comprehensive Stroke Center, Department of Neurology, The J. Sagol Neuroscience Center, Chaim Sheba Medical Center, Tel HaShomer, Israel.,Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ekaterina Feingold
- Comprehensive Stroke Center, Department of Neurology, The J. Sagol Neuroscience Center, Chaim Sheba Medical Center, Tel HaShomer, Israel.,Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Orna Gera
- Comprehensive Stroke Center, Department of Neurology, The J. Sagol Neuroscience Center, Chaim Sheba Medical Center, Tel HaShomer, Israel.,Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Physical Therapy, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Joab Chapman
- Comprehensive Stroke Center, Department of Neurology, The J. Sagol Neuroscience Center, Chaim Sheba Medical Center, Tel HaShomer, Israel.,Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Neurology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Robert and Martha Harden Chair in Mental and Neurological Diseases, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - David Tanne
- Comprehensive Stroke Center, Department of Neurology, The J. Sagol Neuroscience Center, Chaim Sheba Medical Center, Tel HaShomer, Israel.,Department of Neurology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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53
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Sweeney AM, Fleming KE, McCauley JP, Rodriguez MF, Martin ET, Sousa AA, Leapman RD, Scimemi A. PAR1 activation induces rapid changes in glutamate uptake and astrocyte morphology. Sci Rep 2017; 7:43606. [PMID: 28256580 PMCID: PMC5335386 DOI: 10.1038/srep43606] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 01/26/2017] [Indexed: 01/24/2023] Open
Abstract
The G-protein coupled, protease-activated receptor 1 (PAR1) is a membrane protein expressed in astrocytes. Fine astrocytic processes are in tight contact with neurons and blood vessels and shape excitatory synaptic transmission due to their abundant expression of glutamate transporters. PAR1 is proteolytically-activated by bloodstream serine proteases also involved in the formation of blood clots. PAR1 activation has been suggested to play a key role in pathological states like thrombosis, hemostasis and inflammation. What remains unclear is whether PAR1 activation also regulates glutamate uptake in astrocytes and how this shapes excitatory synaptic transmission among neurons. Here we show that, in the mouse hippocampus, PAR1 activation induces a rapid structural re-organization of the neuropil surrounding glutamatergic synapses, which is associated with faster clearance of synaptically-released glutamate from the extracellular space. This effect can be recapitulated using realistic 3D Monte Carlo reaction-diffusion simulations, based on axial scanning transmission electron microscopy (STEM) tomography reconstructions of excitatory synapses. The faster glutamate clearance induced by PAR1 activation leads to short- and long-term changes in excitatory synaptic transmission. Together, these findings identify PAR1 as an important regulator of glutamatergic signaling in the hippocampus and a possible target molecule to limit brain damage during hemorrhagic stroke.
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Affiliation(s)
- Amanda M Sweeney
- SUNY Albany, Dept. Biology, 1400 Washington Avenue, Albany NY 12222, USA
| | - Kelsey E Fleming
- SUNY Albany, Dept. Biology, 1400 Washington Avenue, Albany NY 12222, USA
| | - John P McCauley
- SUNY Albany, Dept. Biology, 1400 Washington Avenue, Albany NY 12222, USA
| | - Marvin F Rodriguez
- SUNY Albany, Dept. Biology, 1400 Washington Avenue, Albany NY 12222, USA.,SUNY Oneonta, Dept. Computer Science, 108 Ravine Parkway, Oneonta NY 13820, USA
| | - Elliot T Martin
- SUNY Albany, Dept. Biology, 1400 Washington Avenue, Albany NY 12222, USA
| | - Alioscka A Sousa
- National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, 9000 Rockville Pike, Bethesda MD 20852, USA
| | - Richard D Leapman
- National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, 9000 Rockville Pike, Bethesda MD 20852, USA
| | - Annalisa Scimemi
- SUNY Albany, Dept. Biology, 1400 Washington Avenue, Albany NY 12222, USA
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Wojtukiewicz MZ, Hempel D, Sierko E, Tucker SC, Honn KV. Thrombin-unique coagulation system protein with multifaceted impacts on cancer and metastasis. Cancer Metastasis Rev 2017; 35:213-33. [PMID: 27189210 DOI: 10.1007/s10555-016-9626-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The association between blood coagulation and cancer development is well recognized. Thrombin, the pleiotropic enzyme best known for its contribution to fibrin formation and platelet aggregation during vascular hemostasis, may also trigger cellular events through protease-activated receptors, PAR-1 and PAR-4, leading to cancer progression. Our pioneering findings provided evidence that thrombin contributes to cancer metastasis by increasing adhesive potential of malignant cells. However, there is evidence that thrombin regulates every step of cancer dissemination: (1) cancer cell invasion, detachment from primary tumor, migration; (2) entering the blood vessel; (3) surviving in vasculature; (4) extravasation; (5) implantation in host organs. Recent studies have provided new molecular data about thrombin generation in cancer patients and the mechanisms by which thrombin contributes to transendothelial migration, platelet/tumor cell interactions, angiogenesis, and other processes. Though a great deal is known regarding the role of thrombin in cancer dissemination, there are new data for multiple thrombin-mediated events that justify devoting focus to this topic with a comprehensive approach.
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Affiliation(s)
- Marek Z Wojtukiewicz
- Department of Oncology, Medical University of Bialystok, 12 Ogrodowa St., 15-025, Bialystok, Poland. .,Department of Clinical Oncology, Comprehensive Cancer Center in Bialystok, Bialystok, Poland.
| | - Dominika Hempel
- Department of Oncology, Medical University of Bialystok, 12 Ogrodowa St., 15-025, Bialystok, Poland.,Department of Radiotherapy, Comprehensive Cancer Center in Bialystok, Bialystok, Poland
| | - Ewa Sierko
- Department of Oncology, Medical University of Bialystok, 12 Ogrodowa St., 15-025, Bialystok, Poland.,Department of Radiotherapy, Comprehensive Cancer Center in Bialystok, Bialystok, Poland
| | - Stephanie C Tucker
- Bioactive Lipids Research Program, Department of Pathology-School of Medicine, Wayne State University, Detroit, MI, USA
| | - Kenneth V Honn
- Bioactive Lipids Research Program, Department of Pathology-School of Medicine, Wayne State University, Detroit, MI, USA.,Department of Chemistry, Wayne State University, Detroit, MI, USA.,Department of Oncology, Karmanos Cancer Institute, Detroit, MI, USA
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55
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Pompili E, Fabrizi C, Somma F, Correani V, Maras B, Schininà ME, Ciraci V, Artico M, Fornai F, Fumagalli L. PAR1 activation affects the neurotrophic properties of Schwann cells. Mol Cell Neurosci 2017; 79:23-33. [PMID: 28064059 DOI: 10.1016/j.mcn.2017.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 12/14/2016] [Accepted: 01/01/2017] [Indexed: 01/02/2023] Open
Abstract
Protease-activated receptor-1 (PAR1) is the prototypic member of a family of four G-protein-coupled receptors that signal in response to extracellular proteases. In the peripheral nervous system, the expression and/or the role of PARs are still poorly investigated. High PAR1 mRNA expression was found in the rat dorsal root ganglia and the signal intensity of PAR1 mRNA increased in response to sciatic nerve transection. In the sciatic nerve, functional PAR1 receptor was reported at the level of non-compacted Schwann cell myelin microvilli of the nodes of Ranvier. Schwann cells are the principal population of glial cells of the peripheral nervous system which myelinate axons playing an important role during axonal regeneration and remyelination. The present study was undertaken in order to determine if the activation of PAR1 affects the neurotrophic properties of Schwann cells. Our results suggest that the stimulation of PAR1 could potentiate the Schwann cell ability to favour nerve regeneration. In fact, the conditioned medium obtained from Schwann cell cultures challenged with a specific PAR1 activating peptide (PAR1 AP) displays increased neuroprotective and neurotrophic properties with respect to the culture medium from untreated Schwann cells. The proteomic analysis of secreted proteins in untreated and PAR1 AP-treated Schwann cells allowed the identification of factors differentially expressed in the two samples. Some of them (such as macrophage migration inhibitory factor, matrix metalloproteinase-2, decorin, syndecan 4, complement C1r subcomponent, angiogenic factor with G patch and FHA domains 1) appear to be transcriptionally regulated after PAR1 AP treatment as shown by RT-PCR.
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Affiliation(s)
- Elena Pompili
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, Rome, Italy.
| | - Cinzia Fabrizi
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, Rome, Italy
| | - Francesca Somma
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, Rome, Italy
| | - Virginia Correani
- Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy
| | - Bruno Maras
- Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy
| | | | - Viviana Ciraci
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, Rome, Italy
| | - Marco Artico
- Department of Sensory Organs, Sapienza University of Rome, Rome, Italy
| | - Francesco Fornai
- Department of Human Morphology and Applied Biology, University of Pisa, Pisa, Italy; IRCCS Neuromed, Pozzilli, Italy
| | - Lorenzo Fumagalli
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, Rome, Italy
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56
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Yang JN, Chen J, Xiao M. A protease-activated receptor 1 antagonist protects against global cerebral ischemia/reperfusion injury after asphyxial cardiac arrest in rabbits. Neural Regen Res 2017; 12:242-249. [PMID: 28400806 PMCID: PMC5361508 DOI: 10.4103/1673-5374.199011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Cerebral ischemia/reperfusion injury is partially mediated by thrombin, which causes brain damage through protease-activated receptor 1 (PAR1). However, the role and mechanisms underlying the effects of PAR1 activation require further elucidation. Therefore, the present study investigated the effects of the PAR1 antagonist SCH79797 in a rabbit model of global cerebral ischemia induced by cardiac arrest. SCH79797 was intravenously administered 10 minutes after the model was established. Forty-eight hours later, compared with those administered saline, rabbits receiving SCH79797 showed markedly decreased neuronal damage as assessed by serum neuron specific enolase levels and less neurological dysfunction as determined using cerebral performance category scores. Additionally, in the hippocampus, cell apoptosis, polymorphonuclear cell infiltration, and c-Jun levels were decreased, whereas extracellular signal-regulated kinase phosphorylation levels were increased. All of these changes were inhibited by the intravenous administration of the phosphoinositide 3-kinase/Akt pathway inhibitor LY29004 (3 mg/kg) 10 minutes before the SCH79797 intervention. These findings suggest that SCH79797 mitigates brain injury via anti-inflammatory and anti-apoptotic effects, possibly by modulating the extracellular signal-regulated kinase, c-Jun N-terminal kinase/c-Jun and phosphoinositide 3-kinase/Akt pathways.
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Affiliation(s)
- Jing-Ning Yang
- Department of Emergency Medicine, Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei Province, China; Department of Immunology, Hubei University of Medicine, Shiyan, Hubei Province, China
| | - Jun Chen
- Department of Immunology, Hubei University of Medicine, Shiyan, Hubei Province, China
| | - Min Xiao
- Department of Emergency Medicine, Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei Province, China
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57
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Protease induced plasticity: matrix metalloproteinase-1 promotes neurostructural changes through activation of protease activated receptor 1. Sci Rep 2016; 6:35497. [PMID: 27762280 PMCID: PMC5071868 DOI: 10.1038/srep35497] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 09/30/2016] [Indexed: 11/08/2022] Open
Abstract
Matrix metalloproteinases (MMPs) are a family of secreted endopeptidases expressed by neurons and glia. Regulated MMP activity contributes to physiological synaptic plasticity, while dysregulated activity can stimulate injury. Disentangling the role individual MMPs play in synaptic plasticity is difficult due to overlapping structure and function as well as cell-type specific expression. Here, we develop a novel system to investigate the selective overexpression of a single MMP driven by GFAP expressing cells in vivo. We show that MMP-1 induces cellular and behavioral phenotypes consistent with enhanced signaling through the G-protein coupled protease activated receptor 1 (PAR1). Application of exogenous MMP-1, in vitro, stimulates PAR1 dependent increases in intracellular Ca2+ concentration and dendritic arborization. Overexpression of MMP-1, in vivo, increases dendritic complexity and induces biochemical and behavioral endpoints consistent with increased GPCR signaling. These data are exciting because we demonstrate that an astrocyte-derived protease can influence neuronal plasticity through an extracellular matrix independent mechanism.
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Abstract
Although many studies have demonstrated that components of the hemostatic system may be involved in signaling leading to cancer progression, the potential mechanisms by which they contribute to cancer dissemination are not yet precisely understood. Among known coagulant factors, tissue factor (TF) and thrombin play a pivotal role in cancer invasion. They may be generated in the tumor microenvironment independently of blood coagulation and can induce cell signaling through activation of protease-activated receptors (PARs). PARs are transmembrane G-protein-coupled receptors (GPCRs) that are activated by a unique proteolytic mechanism. They play important roles in vascular physiology, neural tube closure, hemostasis, and inflammation. All of these agents (TF, thrombin, PARs—mainly PAR-1 and PAR-2) are thought to promote cancer invasion and metastasis at least in part by facilitating tumor cell migration, angiogenesis, and interactions with host vascular cells, including platelets, fibroblasts, and endothelial cells lining blood vessels. Here, we discuss the role of PARs and their activators in cancer progression, focusing on TF- and thrombin-mediated actions. Therapeutic options tailored specifically to inhibit PAR-induced signaling in cancer patients are presented as well.
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59
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Radulovic M, Yoon H, Wu J, Mustafa K, Scarisbrick IA. Targeting the thrombin receptor modulates inflammation and astrogliosis to improve recovery after spinal cord injury. Neurobiol Dis 2016; 93:226-42. [PMID: 27145117 PMCID: PMC4930708 DOI: 10.1016/j.nbd.2016.04.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 04/08/2016] [Accepted: 04/29/2016] [Indexed: 02/07/2023] Open
Abstract
The deregulation of serine protease activity is a common feature of neurological injury, but little is known regarding their mechanisms of action or whether they can be targeted to facilitate repair. In this study we demonstrate that the thrombin receptor (Protease Activated Receptor 1, (PAR1)) serves as a critical translator of the spinal cord injury (SCI) proteolytic microenvironment into a cascade of pro-inflammatory events that contribute to astrogliosis and functional decline. PAR1 knockout mice displayed improved locomotor recovery after SCI and reduced signatures of inflammation and astrogliosis, including expression of glial fibrillary acidic protein (GFAP), vimentin, and STAT3 signaling. SCI-associated elevations in pro-inflammatory cytokines such as IL-1β and IL-6 were also reduced in PAR1-/- mice and co-ordinate improvements in tissue sparing and preservation of NeuN-positive ventral horn neurons, and PKCγ corticospinal axons, were observed. PAR1 and its agonist's thrombin and neurosin were expressed by perilesional astrocytes and each agonist increased the production of IL-6 and STAT3 signaling in primary astrocyte cultures in a PAR1-dependent manner. In turn, IL-6-stimulated astrocytes increased expression of PAR1, thrombin, and neurosin, pointing to a model in which PAR1 activation contributes to increased astrogliosis by feedforward- and feedback-signaling dynamics. Collectively, these findings identify the thrombin receptor as a key mediator of inflammation and astrogliosis in the aftermath of SCI that can be targeted to reduce neurodegeneration and improve neurobehavioral recovery.
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Affiliation(s)
- Maja Radulovic
- Neurobiology of Disease Program, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester 55905, MN, United States
| | - Hyesook Yoon
- Department of Physical Medicine and Rehabilitation, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester, MN 55905, United States; Department of Physiology and Biomedical Engineering, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester, MN 55905, United States
| | - Jianmin Wu
- Department of Physical Medicine and Rehabilitation, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester, MN 55905, United States
| | - Karim Mustafa
- Neurobiology of Disease Program, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester 55905, MN, United States
| | - Isobel A Scarisbrick
- Neurobiology of Disease Program, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester 55905, MN, United States; Department of Physical Medicine and Rehabilitation, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester, MN 55905, United States; Department of Physiology and Biomedical Engineering, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester, MN 55905, United States.
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Auvergne R, Wu C, Connell A, Au S, Cornwell A, Osipovitch M, Benraiss A, Dangelmajer S, Guerrero-Cazares H, Quinones-Hinojosa A, Goldman SA. PAR1 inhibition suppresses the self-renewal and growth of A2B5-defined glioma progenitor cells and their derived gliomas in vivo. Oncogene 2016; 35:3817-28. [PMID: 26616854 PMCID: PMC4885796 DOI: 10.1038/onc.2015.452] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 09/14/2015] [Accepted: 10/22/2015] [Indexed: 12/15/2022]
Abstract
Glioblastoma (GBM) remains the most common and lethal intracranial tumor. In a comparison of gene expression by A2B5-defined tumor-initiating progenitor cells (TPCs) to glial progenitor cells derived from normal adult human brain, we found that the F2R gene encoding PAR1 was differentially overexpressed by A2B5-sorted TPCs isolated from gliomas at all stages of malignant development. In this study, we asked if PAR1 is causally associated with glioma progression. Lentiviral knockdown of PAR1 inhibited the expansion and self-renewal of human GBM-derived A2B5(+) TPCs in vitro, while pharmacological inhibition of PAR 1 similarly slowed both the growth and migration of A2B5(+) TPCs in culture. In addition, PAR1 silencing potently suppressed tumor expansion in vivo, and significantly prolonged the survival of mice following intracranial transplantation of human TPCs. These data strongly suggest the importance of PAR1 to the self-renewal and tumorigenicity of A2B5-defined glioma TPCs; as such, the abrogation of PAR1-dependent signaling pathways may prove a promising strategy for gliomas.
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Affiliation(s)
- R Auvergne
- Department of Neurology, Neurology University of Rochester Medical Center, Center for Translational Neuromedicine, Rochester, NY, USA
- Center for Translational Neuromedicine, Neurology University of Rochester Medical Center, Rochester, NY, USA
| | - C Wu
- Department of Neurology, Neurology University of Rochester Medical Center, Center for Translational Neuromedicine, Rochester, NY, USA
- Center for Translational Neuromedicine, Neurology University of Rochester Medical Center, Rochester, NY, USA
| | - A Connell
- Department of Neurology, Neurology University of Rochester Medical Center, Center for Translational Neuromedicine, Rochester, NY, USA
- Center for Translational Neuromedicine, Neurology University of Rochester Medical Center, Rochester, NY, USA
| | - S Au
- Department of Neurology, Neurology University of Rochester Medical Center, Center for Translational Neuromedicine, Rochester, NY, USA
- Center for Translational Neuromedicine, Neurology University of Rochester Medical Center, Rochester, NY, USA
| | - A Cornwell
- Department of Neurology, Neurology University of Rochester Medical Center, Center for Translational Neuromedicine, Rochester, NY, USA
- Center for Translational Neuromedicine, Neurology University of Rochester Medical Center, Rochester, NY, USA
| | - M Osipovitch
- Department of Neurology, Neurology University of Rochester Medical Center, Center for Translational Neuromedicine, Rochester, NY, USA
- Center for Translational Neuromedicine, Neurology University of Rochester Medical Center, Rochester, NY, USA
| | - A Benraiss
- Department of Neurology, Neurology University of Rochester Medical Center, Center for Translational Neuromedicine, Rochester, NY, USA
- Center for Translational Neuromedicine, Neurology University of Rochester Medical Center, Rochester, NY, USA
| | - S Dangelmajer
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - H Guerrero-Cazares
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - A Quinones-Hinojosa
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - SA Goldman
- Department of Neurology, Neurology University of Rochester Medical Center, Center for Translational Neuromedicine, Rochester, NY, USA
- Center for Translational Neuromedicine, Neurology University of Rochester Medical Center, Rochester, NY, USA
- Center for Basic and Translational Neuroscience, University of Copenhagen, Copenhagen, Denmark
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Duan ZZ, Zhang F, Li FY, Luan YF, Guo P, Li YH, Liu Y, Qi SH. Protease activated receptor 1 (PAR1) enhances Src-mediated tyrosine phosphorylation of NMDA receptor in intracerebral hemorrhage (ICH). Sci Rep 2016; 6:29246. [PMID: 27385592 PMCID: PMC4935874 DOI: 10.1038/srep29246] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 06/14/2016] [Indexed: 12/20/2022] Open
Abstract
It has been demonstrated that Src could modulate NMDA receptor, and PAR1 could also affect NMDAR signaling. However, whether PAR1 could regulate NMDAR through Src under ICH has not yet been investigated. In this study, we demonstrated the role of Src-PSD95-GluN2A signaling cascades in rat ICH model and in vitro thrombin challenged model. Using the PAR1 agonist SFLLR, antagonist RLLFS and Src inhibitor PP2, electrophysiological analysis showed that PAR1 regulated NMDA-induced whole-cell currents (INMDA) though Src in primary cultured neurons. Both in vivo and in vitro results showed the elevated phosphorylation of tyrosine in Src and GluN2A and enhanced interaction of the Src-PSD95-GluN2A under model conditions. Treatment with the PAR1 antagonist RLLFS, AS-PSD95 (Antisense oligonucleotide against PSD95) and Src inhibitor PP2 inhibited the interaction among Src-PSD95-GluN2A, and p-Src, p-GluN2A. Co-application of SFLLR and AS-PSD95, PP2, or MK801 (NMDAR inhibitor) abolished the effect of SF. In conclusion, our results demonstrated that activated thrombin receptor PAR1 induced Src activation, enhanced the interaction among Src-PSD95-GluN2A signaling modules, and up-regulated GluN2A phosphorylation after ICH injury. Elucidation of such signaling cascades would possibly provide novel targets for ICH treatment.
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Affiliation(s)
- Zhen-Zhen Duan
- Research Center for Biochemistry and Molecular Biology and Provincial Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, 221002, P. R. China
| | - Feng Zhang
- Research Center for Biochemistry and Molecular Biology and Provincial Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, 221002, P. R. China
| | - Feng-Ying Li
- Research Center for Biochemistry and Molecular Biology and Provincial Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, 221002, P. R. China
| | - Yi-Fei Luan
- Research Center for Biochemistry and Molecular Biology and Provincial Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, 221002, P. R. China
| | - Peng Guo
- Research Center for Biochemistry and Molecular Biology and Provincial Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, 221002, P. R. China
| | - Yi-Hang Li
- Research Center for Biochemistry and Molecular Biology and Provincial Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, 221002, P. R. China
| | - Yong Liu
- Research Center for Biochemistry and Molecular Biology and Provincial Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, 221002, P. R. China
| | - Su-Hua Qi
- Research Center for Biochemistry and Molecular Biology and Provincial Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, 221002, P. R. China
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Schuldt G, Galanis C, Strehl A, Hick M, Schiener S, Lenz M, Deller T, Maggio N, Vlachos A. Inhibition of Protease-Activated Receptor 1 Does not Affect Dendritic Homeostasis of Cultured Mouse Dentate Granule Cells. Front Neuroanat 2016; 10:64. [PMID: 27378862 PMCID: PMC4904007 DOI: 10.3389/fnana.2016.00064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 05/27/2016] [Indexed: 12/25/2022] Open
Abstract
Protease-activated receptors (PARs) are widely expressed in the central nervous system (CNS). While a firm link between PAR1-activation and functional synaptic and intrinsic neuronal properties exists, studies on the role of PAR1 in neural structural plasticity are scarce. The physiological function of PAR1 in the brain remains not well understood. We here sought to determine whether prolonged pharmacologic PAR1-inhibition affects dendritic morphologies of hippocampal neurons. To address this question we employed live-cell microscopy of mouse dentate granule cell dendrites in 3-week old entorhino-hippocampal slice cultures prepared from Thy1-GFP mice. A subset of cultures were treated with the PAR1-inhibitor SCH79797 (1 μM; up to 3 weeks). No major effects of PAR1-inhibition on static and dynamic parameters of dentate granule cell dendrites were detected under control conditions. Granule cells of PAR1-deficient slice cultures showed unaltered dendritic morphologies, dendritic spine densities and excitatory synaptic strength. Furthermore, we report that PAR1-inhibition does not prevent dendritic retraction following partial deafferentation in vitro. Consistent with this finding, no major changes in PAR1-mRNA levels were detected in the denervated dentate gyrus (DG). We conclude that neural PAR1 is not involved in regulating the steady-state dynamics or deafferentation-induced adaptive changes of cultured dentate granule cell dendrites. These results indicate that drugs targeting neural PAR1-signals may not affect the stability and structural integrity of neuronal networks in healthy brain regions.
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Affiliation(s)
- Gerlind Schuldt
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt Frankfurt, Germany
| | - Christos Galanis
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt Frankfurt, Germany
| | - Andreas Strehl
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt Frankfurt, Germany
| | - Meike Hick
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt Frankfurt, Germany
| | - Sabine Schiener
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt Frankfurt, Germany
| | - Maximilian Lenz
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University FrankfurtFrankfurt, Germany; Institute of Anatomy II, Faculty of Medicine, Heinrich-Heine-University DüsseldorfDüsseldorf, Germany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt Frankfurt, Germany
| | - Nicola Maggio
- Department of Neurology, The Sagol Center for Neurosciences, Sheba Medical Center, Affiliated to the Sackler Faculty of Medicine, Tel Aviv UniversityTel Aviv, Israel; Talpiot Medical Leadership Program, Department of Neurology and J. Sagol Neuroscience Center, The Chaim Sheba Medical CenterTel HaShomer, Israel; Sagol School of Neuroscience, Tel Aviv UniversityTel Aviv, Israel
| | - Andreas Vlachos
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University FrankfurtFrankfurt, Germany; Institute of Anatomy II, Faculty of Medicine, Heinrich-Heine-University DüsseldorfDüsseldorf, Germany
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63
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Novel pharmaceutical treatments for minimal traumatic brain injury and evaluation of animal models and methodologies supporting their development. J Neurosci Methods 2016; 272:69-76. [PMID: 26868733 DOI: 10.1016/j.jneumeth.2016.02.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Accepted: 02/01/2016] [Indexed: 12/15/2022]
Abstract
BACKGROUND The need for effective pharmaceuticals within animal models of traumatic brain injury (TBI) continues to be paramount, as TBI remains the major cause of brain damage for children and young adults. While preventative measures may act to reduce the incidence of initial blunt trauma, well-tolerated drugs are needed to target the neurologically damaging internal cascade of molecular mechanisms that follow. Such processes, known collectively as the secondary injury phase, include inflammation, excitotoxicity, and apoptosis among other changes still subject to research. In this article positive treatment findings to mitigate this secondary injury in rodent TBI models will be overviewed, and include recent studies on Exendin-4, N-Acetyl-l-cycteine, Salubrinal and Thrombin. CONCLUSIONS These studies provide representative examples of methodologies that can be combined with widely available in vivo rodent models to evaluate therapeutic approaches of translational relevance, as well as drug targets and biochemical cascades that may slow or accelerate the degenerative processes induced by TBI. They employ well-characterized tests such as the novel object recognition task for assessing cognitive deficits. The application of such methodologies provides both decision points and a gateway for implementation of further translational studies to establish the feasibility of clinical efficacy of potential therapeutic interventions.
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64
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Peña-Ortega F, Rivera-Angulo AJ, Lorea-Hernández JJ. Pharmacological Tools to Study the Role of Astrocytes in Neural Network Functions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 949:47-66. [DOI: 10.1007/978-3-319-40764-7_3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Bushi D, Ben Shimon M, Shavit Stein E, Chapman J, Maggio N, Tanne D. Increased thrombin activity following reperfusion after ischemic stroke alters synaptic transmission in the hippocampus. J Neurochem 2015; 135:1140-8. [PMID: 26390857 DOI: 10.1111/jnc.13372] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 09/15/2015] [Accepted: 09/16/2015] [Indexed: 11/24/2022]
Abstract
Thrombin, a key player in thrombogenesis, affects cells in the brain through activation of its receptors. Low levels of thrombin activity are protective while high levels are toxic. We sought to quantify thrombin activity levels and their spatial distribution in brains of mice following reperfusion after ischemic stroke focusing on infarct, peri-infarct and contralateral areas. In order to find out the contribution of brain-derived thrombin, mRNA levels of both prothrombin and factor X were determined. Furthermore, we assessed the effect of thrombin levels that were measured in the ischemic brain on synaptic transmission. We found that in the brains of mice following transient middle cerebral artery occlusion, thrombin activity is elevated throughout the ischemic hemisphere, including in peri-infarct areas (90 ± 33 and 60 ± 18 mU/mL, in the infarct and peri-infarct areas, respectively, compared to 11 ± 3 and 12 ± 5 mU/mL, in the corresponding contralateral areas; mean ± SE; p < 0.05). Brain mRNA levels of prothrombin and, in particular, factor X are up-regulated in the ischemic core. Hippocampal slices treated with thrombin concentrations as found in the ischemic hemisphere show altered synaptic responses. We conclude that high thrombin activity following reperfusion after ischemic stroke may cause synaptic dysfunction. Following transient middle cerebral artery occlusion in mice, thrombin activity is elevated throughout the ischemic hemisphere, including in peri-infarct areas. Brain mRNA levels of prothrombin and factor X are up-regulated in the ischemic core. Thrombin is known to affect synaptic function in a concentration dependent manner and hippocampal slices treated with the concentrations found in the ischemic hemisphere show altered synaptic responses. We conclude that in ischemic stroke, the high brain thrombin activity found after reperfusion may cause synaptic dysfunction.
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Affiliation(s)
- Doron Bushi
- Comprehensive Stroke Center, Department of Neurology and The J. Sagol Neuroscience Center, Chaim Sheba Medical Center, Tel HaShomer, Israel.,Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Marina Ben Shimon
- Comprehensive Stroke Center, Department of Neurology and The J. Sagol Neuroscience Center, Chaim Sheba Medical Center, Tel HaShomer, Israel.,Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Efrat Shavit Stein
- Comprehensive Stroke Center, Department of Neurology and The J. Sagol Neuroscience Center, Chaim Sheba Medical Center, Tel HaShomer, Israel
| | - Joab Chapman
- Comprehensive Stroke Center, Department of Neurology and The J. Sagol Neuroscience Center, Chaim Sheba Medical Center, Tel HaShomer, Israel.,Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Neurology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Robert and Martha Harden Chair in Mental and Neurological Diseases, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Nicola Maggio
- Comprehensive Stroke Center, Department of Neurology and The J. Sagol Neuroscience Center, Chaim Sheba Medical Center, Tel HaShomer, Israel.,Department of Neurology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Talpiot Medical Leadership Program, Chaim Sheba Medical Center, Tel Ha Shomer, Israel
| | - David Tanne
- Comprehensive Stroke Center, Department of Neurology and The J. Sagol Neuroscience Center, Chaim Sheba Medical Center, Tel HaShomer, Israel.,Department of Neurology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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66
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Zhang D, Li S, Hu L, Sheng L, Chen L. Modulation of protease-activated receptor expression by Porphyromonas gingivalis in human gingival epithelial cells. BMC Oral Health 2015; 15:128. [PMID: 26476532 PMCID: PMC4609475 DOI: 10.1186/s12903-015-0105-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 10/05/2015] [Indexed: 02/07/2023] Open
Abstract
Background Protease-activated receptors (PARs) are G-protein-coupled receptors with an active role in mediating inflammation, pain and other functions. The oral pathogen Porphyromonas gingivalis (P. gingivalis) secretes proteases that activate PARs. The aim of this study was to elucidate the role of PARs in the pathogenesis of chronic periodontitis by expression analysis of PARs in human gingival epithelial cells (GECs) before and after P. gingivalis supernatants treatment. Methods GECs were isolated from healthy human gingival tissue samples. The expression of PARs in GECs was determined by reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometry. The effect of P. gingivalis proteases was investigated by quantitative real-time reverse transcription polymerase chain reaction (QRT-PCR) and flow cytometry. Results PAR-1, PAR-2, and PAR-3 were expressed in GECs. PAR-4 was not found by both RT-PCR and flow cytometry. Analysis of gene expression using QRT-PCR showed an up-regulation of PAR-2 mRNA in comparison to the untreated control cells (P < 0.05). In contrast, the mRNA expressions of PAR-1 and PAR-3 were significantly down-regulated (P > 0.05) in response to P. gingivalis supernatant compared to that in unstimulated control cells. This effect was abrogated by the protease inhibitor TLCK (P < 0.05). The results of flow cytometry indicated PARs protein levels consistent with mRNA levels in the results of QRT-PCR. Conclusions Our study shows that PAR-1, PAR-2 and PAR-3 are expressed in GECs. P. gingivalis proteases play a role in the regulation of innate immune responses in GECs. GECs use PARs to recognize P. gingivalis and mediate cell responses involved in innate immunity.
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Affiliation(s)
- Diya Zhang
- Dental Department, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, 310016, China.
| | - Shenglai Li
- Department of Oral and Maxillofacial Surgery, Stomatology Hospital, School of Medicine, Zhejiang University, Hangzhou, 310006, China.
| | - Lingjing Hu
- Department of Oral Medicine, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China.
| | - Lieping Sheng
- Dental Department, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, 310016, China.
| | - Lili Chen
- Department of Oral Medicine, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China.
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67
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Kim HN, Kim YR, Ahn SM, Lee SK, Shin HK, Choi BT. Protease activated receptor-1 antagonist ameliorates the clinical symptoms of experimental autoimmune encephalomyelitis via inhibiting breakdown of blood-brain barrier. J Neurochem 2015; 135:577-88. [PMID: 26285165 DOI: 10.1111/jnc.13285] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 07/10/2015] [Accepted: 08/04/2015] [Indexed: 01/12/2023]
Abstract
To evaluate the question of whether protease activated receptor-1 (PAR-1) antagonist is a potential therapeutic target in multiple sclerosis, we treated experimental autoimmune encephalomyelitis (EAE) mice with two PAR-1 antagonists, KC-A0590 and SCH-530348. Treatment with both antagonists resulted in a significant decrease in the clinical characteristics of EAE mice by suppressing demyelination and infiltration of inflammatory cells in the spinal cord and brain, as well as a significantly reducing the increased thrombin and tumor necrosis factor-α. Profound leakage of dextran was observed in the brain of EAE mice. However, treatment with PAR-1 antagonists resulted in the stabilization of vascular endothelial cells and reduced blood-brain barrier breakdown with suppression of inflammatory response. Treatment with PAR-1 antagonists also resulted in down-regulated expression of matrix metalloproteinase-9 and preserved expression of occludin and zonula occludens (ZO)-1 in the brain and their significant expression was confirmed in neurons, astrocytes, and vascular endothelial cells. Finally, endothelial cells and primary cultured astrocytes were treated with PAR-1 antagonists; both antagonists suppressed thrombin-induced breakdown of ZO-1 in endothelial cells and secretion of matrix metalloproteinase-9 in astrocytes. Collectively, our results suggest that PAR-1 antagonist is effective in attenuation of the clinical symptoms of EAE mice by stabilizing the blood-brain barrier and may have therapeutic potential for treatment of multiple sclerosis.
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Affiliation(s)
- Ha Neui Kim
- Department of Korean Medical Science, Pusan National University, Yangsan, Korea
| | - Yu Ri Kim
- Department of Korean Medical Science, Pusan National University, Yangsan, Korea
| | - Sung Min Ahn
- Department of Korean Medical Science, Pusan National University, Yangsan, Korea
| | - Sun Kyung Lee
- Korea Research Institute of Chemical Technology, Daejeon, Korea
| | - Hwa Kyoung Shin
- Division of Meridian and Structural Medicine, School of Korean Medicine, Pusan National University, Yangsan, Korea.,Korean Medical Science Research Center for Healthy-Aging, Pusan National University, Yangsan, Korea
| | - Byung Tae Choi
- Department of Korean Medical Science, Pusan National University, Yangsan, Korea.,Division of Meridian and Structural Medicine, School of Korean Medicine, Pusan National University, Yangsan, Korea.,Korean Medical Science Research Center for Healthy-Aging, Pusan National University, Yangsan, Korea
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68
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Acton D, Miles GB. Stimulation of Glia Reveals Modulation of Mammalian Spinal Motor Networks by Adenosine. PLoS One 2015; 10:e0134488. [PMID: 26252389 PMCID: PMC4529192 DOI: 10.1371/journal.pone.0134488] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 07/09/2015] [Indexed: 01/05/2023] Open
Abstract
Despite considerable evidence that glia can release modulators to influence the excitability of neighbouring neurons, the importance of gliotransmission for the operation of neural networks and in shaping behaviour remains controversial. Here we characterise the contribution of glia to the modulation of the mammalian spinal central pattern generator for locomotion, the output of which is directly relatable to a defined behaviour. Glia were stimulated by specific activation of protease-activated receptor-1 (PAR1), an endogenous G-protein coupled receptor preferentially expressed by spinal glia during ongoing activity of the spinal central pattern generator for locomotion. Selective activation of PAR1 by the agonist TFLLR resulted in a reversible reduction in the frequency of locomotor-related bursting recorded from ventral roots of spinal cord preparations isolated from neonatal mice. In the presence of the gliotoxins methionine sulfoximine or fluoroacetate, TFLLR had no effect, confirming the specificity of PAR1 activation to glia. The modulation of burst frequency upon PAR1 activation was blocked by the non-selective adenosine-receptor antagonist theophylline and by the A1-receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine, but not by the A2A-receptor antagonist SCH5826, indicating production of extracellular adenosine upon glial stimulation, followed by A1-receptor mediated inhibition of neuronal activity. Modulation of network output following glial stimulation was also blocked by the ectonucleotidase inhibitor ARL67156, indicating glial release of ATP and its subsequent degradation to adenosine rather than direct release of adenosine. Glial stimulation had no effect on rhythmic activity recorded following blockade of inhibitory transmission, suggesting that glial cell-derived adenosine acts via inhibitory circuit components to modulate locomotor-related output. Finally, the modulation of network output by endogenous adenosine was found to scale with the frequency of network activity, implying activity-dependent release of adenosine. Together, these data indicate that glia play an active role in the modulation of mammalian locomotor networks, providing negative feedback control that may stabilise network activity.
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Affiliation(s)
- David Acton
- School of Psychology and Neuroscience, University of St Andrews, Fife, United Kingdom
| | - Gareth B. Miles
- School of Psychology and Neuroscience, University of St Andrews, Fife, United Kingdom
- * E-mail:
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Ben Shimon M, Lenz M, Ikenberg B, Becker D, Shavit Stein E, Chapman J, Tanne D, Pick CG, Blatt I, Neufeld M, Vlachos A, Maggio N. Thrombin regulation of synaptic transmission and plasticity: implications for health and disease. Front Cell Neurosci 2015; 9:151. [PMID: 25954157 PMCID: PMC4404867 DOI: 10.3389/fncel.2015.00151] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/01/2015] [Indexed: 11/13/2022] Open
Abstract
Thrombin, a serine protease involved in the blood coagulation cascade has been shown to affect neural function following blood-brain barrier breakdown. However, several lines of evidence exist that thrombin is also expressed in the brain under physiological conditions, suggesting an involvement of thrombin in the regulation of normal brain functions. Here, we review ours’ as well as others’ recent work on the role of thrombin in synaptic transmission and plasticity through direct or indirect activation of Protease-Activated Receptor-1 (PAR1). These studies propose a novel role of thrombin in synaptic plasticity, both in physiology as well as in neurological diseases associated with increased brain thrombin/PAR1 levels.
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Affiliation(s)
- Marina Ben Shimon
- Department of Neurology, The J. Sagol Neuroscience Center, The Chaim Sheba Medical Center Tel HaShomer, Israel
| | - Maximilian Lenz
- Department of Neurology, The J. Sagol Neuroscience Center, The Chaim Sheba Medical Center Tel HaShomer, Israel ; Institute of Clinical Neuroanatomy, Neuroscience Center Frankfurt, Goethe-University Frankfurt Frankfurt, Germany
| | - Benno Ikenberg
- Department of Neurology, The J. Sagol Neuroscience Center, The Chaim Sheba Medical Center Tel HaShomer, Israel ; Institute of Clinical Neuroanatomy, Neuroscience Center Frankfurt, Goethe-University Frankfurt Frankfurt, Germany
| | - Denise Becker
- Institute of Clinical Neuroanatomy, Neuroscience Center Frankfurt, Goethe-University Frankfurt Frankfurt, Germany
| | - Efrat Shavit Stein
- Department of Neurology, The J. Sagol Neuroscience Center, The Chaim Sheba Medical Center Tel HaShomer, Israel
| | - Joab Chapman
- Department of Neurology, The J. Sagol Neuroscience Center, The Chaim Sheba Medical Center Tel HaShomer, Israel ; Department of Neurology, The Sackler School of Medicine, Tel Aviv University Tel Aviv, Israel
| | - David Tanne
- Department of Neurology, The J. Sagol Neuroscience Center, The Chaim Sheba Medical Center Tel HaShomer, Israel ; Department of Neurology, The Sackler School of Medicine, Tel Aviv University Tel Aviv, Israel
| | - Chaim G Pick
- Department of Anatomy and Anthropology, The Sackler School of Medicine, Tel Aviv University Tel Aviv, Israel
| | - Ilan Blatt
- Department of Neurology, The J. Sagol Neuroscience Center, The Chaim Sheba Medical Center Tel HaShomer, Israel ; Department of Neurology, The Sackler School of Medicine, Tel Aviv University Tel Aviv, Israel
| | - Miri Neufeld
- Department of Neurology, The J. Sagol Neuroscience Center, The Chaim Sheba Medical Center Tel HaShomer, Israel ; Department of Neurology, The Sackler School of Medicine, Tel Aviv University Tel Aviv, Israel ; Department of Neurology and Epilepsy Unit, The Tel Aviv Sourasky Medical Center Tel Aviv, Israel
| | - Andreas Vlachos
- Institute of Clinical Neuroanatomy, Neuroscience Center Frankfurt, Goethe-University Frankfurt Frankfurt, Germany
| | - Nicola Maggio
- Department of Neurology, The J. Sagol Neuroscience Center, The Chaim Sheba Medical Center Tel HaShomer, Israel ; Talpiot Medical Leadership Program, The Chaim Sheba Medical Center Tel HaShomer, Israel
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PAR1-activated astrocytes in the nucleus of the solitary tract stimulate adjacent neurons via NMDA receptors. J Neurosci 2015; 35:776-85. [PMID: 25589770 DOI: 10.1523/jneurosci.3105-14.2015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Severe autonomic dysfunction, including the loss of control of the cardiovascular, respiratory, and gastrointestinal systems, is a common comorbidity of stroke and other bleeding head injuries. Previous studies suggest that this collapse of autonomic control may be caused by thrombin acting on astrocytic protease-activated receptors (PAR1) in the hindbrain. Using calcium imaging and electrophysiological techniques, we evaluated the mechanisms by which astrocytic PAR1s modulate the activity of presynaptic vagal afferent terminals and postsynaptic neurons in the rat nucleus of the solitary tract (NST). Our calcium-imaging data show that astrocytic and neuronal calcium levels increase after brain slices are treated with the PAR1 agonist SFLLRN-NH2. This increase in activity is blocked by pretreating the slices with the glial metabolic blocker fluorocitrate. In addition, PAR1-activated astrocytes communicate directly with NST neurons by releasing glutamate. Calcium responses to SFLLRN-NH2 in the astrocytes and neurons significantly increase after bath application of the excitatory amino acid transporter blocker DL-threo-β-benzyloxyaspartic acid (TBOA) and significantly decrease after bath application of the NMDA receptor antagonist DL-2-amino-5-phosphonopentanoic acid (DL-AP5). Furthermore, astrocytic glutamate activates neuronal GluN2B-containing NMDA receptors. Voltage-clamp recordings of miniature EPSCs (mEPSCs) from NST neurons show that astrocytes control presynaptic vagal afferent excitability directly under resting and activated conditions. Fluorocitrate significantly decreases mEPSC frequency and SFLLRN-NH2 significantly increases mEPSC frequency. These data show that astrocytes act within a tripartite synapse in the NST, controlling the excitability of both postsynaptic NST neurons and presynaptic vagal afferent terminals.
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Itsekson-Hayosh Z, Shavit-Stein E, Last D, Goez D, Daniels D, Bushi D, Gera O, Zibly Z, Mardor Y, Chapman J, Harnof S. Thrombin Activity and Thrombin Receptor in Rat Glioblastoma Model: Possible Markers and Targets for Intervention? J Mol Neurosci 2015; 56:644-51. [PMID: 25691153 DOI: 10.1007/s12031-015-0512-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 02/04/2015] [Indexed: 11/26/2022]
Abstract
High-grade gliomas constitute a group of aggressive CNS cancers that have high morbidity and mortality rates. Despite extensive research, current therapeutic approaches enable survival beyond 2 years in rare cases only. Thrombin and its main CNS target, protease-activated receptor-1, have been implicated in tumor progression and brain edema. Our aim was to study protease-activated receptor-1 (PAR-1) protein expression and thrombin-like activity levels in both in vitro and in vivo models of glioblastoma and correlate them with the volume of the surrounding edema. We measured the presence of PAR-1 protein using fluorescence immunohistochemistry and assessed thrombin activity in various glial and non-glial cell lines and in a CNS-1 glioma rat model using a thrombin-specific fluorescent assay. Thrombin activity was found to be highly elevated in various high-grade glioma cell lines as well as in non-glial malignant cell lines. In the CNS-1 glioma model, the level of PAR-1 fluorescence in the tumor was significantly elevated compared to adjacent regions of reactive gliosis or distant brain areas. The elevated level of thrombin activity observed in the high-grade glioma positively correlated with tumor-induced brain edema. In conclusion, thrombin is secreted from glioma cells and PAR-1 may be a new biological marker for high-grade gliomas.
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Affiliation(s)
- Ze'ev Itsekson-Hayosh
- Department of Neurosurgery, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel,
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Park H, Han KS, Seo J, Lee J, Dravid SM, Woo J, Chun H, Cho S, Bae JY, An H, Koh W, Yoon BE, Berlinguer-Palmini R, Mannaioni G, Traynelis SF, Bae YC, Choi SY, Lee CJ. Channel-mediated astrocytic glutamate modulates hippocampal synaptic plasticity by activating postsynaptic NMDA receptors. Mol Brain 2015; 8:7. [PMID: 25645137 PMCID: PMC4320468 DOI: 10.1186/s13041-015-0097-y] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 01/15/2015] [Indexed: 11/10/2022] Open
Abstract
Background Activation of G protein coupled receptor (GPCR) in astrocytes leads to Ca2+-dependent glutamate release via Bestrophin 1 (Best1) channel. Whether receptor-mediated glutamate release from astrocytes can regulate synaptic plasticity remains to be fully understood. Results We show here that Best1-mediated astrocytic glutamate activates the synaptic N-methyl-D-aspartate receptor (NMDAR) and modulates NMDAR-dependent synaptic plasticity. Our data show that activation of the protease-activated receptor 1 (PAR1) in hippocampal CA1 astrocytes elevates the glutamate concentration at Schaffer collateral-CA1 (SC-CA1) synapses, resulting in activation of GluN2A-containing NMDARs and NMDAR-dependent potentiation of synaptic responses. Furthermore, the threshold for inducing NMDAR-dependent long-term potentiation (LTP) is lowered when astrocytic glutamate release accompanied LTP induction, suggesting that astrocytic glutamate is significant in modulating synaptic plasticity. Conclusions Our results provide direct evidence for the physiological importance of channel-mediated astrocytic glutamate in modulating neural circuit functions.
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73
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Stein ES, Itsekson-Hayosh Z, Aronovich A, Reisner Y, Bushi D, Pick CG, Tanne D, Chapman J, Vlachos A, Maggio N. Thrombin induces ischemic LTP (iLTP): implications for synaptic plasticity in the acute phase of ischemic stroke. Sci Rep 2015; 5:7912. [PMID: 25604482 PMCID: PMC4300504 DOI: 10.1038/srep07912] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 12/19/2014] [Indexed: 11/15/2022] Open
Abstract
Acute brain ischemia modifies synaptic plasticity by inducing ischemic long-term potentiation (iLTP) of synaptic transmission through the activation of N-Methyl-D-aspartate receptors (NMDAR). Thrombin, a blood coagulation factor, affects synaptic plasticity in an NMDAR dependent manner. Since its activity and concentration is increased in brain tissue upon acute stroke, we sought to clarify whether thrombin could mediate iLTP through the activation of its receptor Protease-Activated receptor 1 (PAR1). Extracellular recordings were obtained in CA1 region of hippocampal slices from C57BL/6 mice. In vitro ischemia was induced by acute (3 minutes) oxygen and glucose deprivation (OGD). A specific ex vivo enzymatic assay was employed to assess thrombin activity in hippocampal slices, while OGD-induced changes in prothrombin mRNA levels were assessed by (RT)qPCR. Upon OGD, thrombin activity increased in hippocampal slices. A robust potentiation of excitatory synaptic strength was detected, which occluded the ability to induce further LTP. Inhibition of either thrombin or its receptor PAR1 blocked iLTP and restored the physiological, stimulus induced LTP. Our study provides important insights on the early changes occurring at excitatory synapses after ischemia and indicates the thrombin/PAR1 pathway as a novel target for developing therapeutic strategies to restore synaptic function in the acute phase of ischemic stroke.
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Affiliation(s)
- Efrat Shavit Stein
- Department of Neurology, The Chaim Sheba Medical Center, Tel HaShomer, Israel
| | | | - Anna Aronovich
- 1] Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel [2] Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | - Yair Reisner
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | - Doron Bushi
- Department of Neurology, The Chaim Sheba Medical Center, Tel HaShomer, Israel
| | - Chaim G Pick
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - David Tanne
- 1] Department of Neurology, The Chaim Sheba Medical Center, Tel HaShomer, Israel [2] Department of Neurology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Joab Chapman
- 1] Department of Neurology, The Chaim Sheba Medical Center, Tel HaShomer, Israel [2] Department of Neurology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Andreas Vlachos
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Nicola Maggio
- 1] Department of Neurology, The Chaim Sheba Medical Center, Tel HaShomer, Israel [2] Talpiot Medical Leadership Program, The Chaim Sheba Medical Center, Tel HaShomer, Israel
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74
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Becker D, Ikenberg B, Schiener S, Maggio N, Vlachos A. NMDA-receptor inhibition restores Protease-Activated Receptor 1 (PAR1) mediated alterations in homeostatic synaptic plasticity of denervated mouse dentate granule cells. Neuropharmacology 2014; 86:212-8. [DOI: 10.1016/j.neuropharm.2014.07.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Revised: 06/30/2014] [Accepted: 07/21/2014] [Indexed: 12/27/2022]
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75
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Lee CJ, Yoon BE. Protease-activated receptor 1-induced GABA release in cultured cortical astrocytes pretreated with GABA is mediated by the Bestrophin-1 channel. Anim Cells Syst (Seoul) 2014. [DOI: 10.1080/19768354.2014.944211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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76
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Plasmin-dependent modulation of the blood-brain barrier: a major consideration during tPA-induced thrombolysis? J Cereb Blood Flow Metab 2014; 34:1283-96. [PMID: 24896566 PMCID: PMC4126105 DOI: 10.1038/jcbfm.2014.99] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 05/09/2014] [Accepted: 05/09/2014] [Indexed: 01/16/2023]
Abstract
Plasmin, the principal downstream product of tissue-type plasminogen activator (tPA), is known for its potent fibrin-degrading capacity but is also recognized for many non-fibrinolytic activities. Curiously, plasmin has not been conclusively linked to blood-brain barrier (BBB) disruption during recombinant tPA (rtPA)-induced thrombolysis in ischemic stroke. This is surprising given the substantial involvement of tPA in the modulation of BBB permeability and the co-existence of tPA and plasminogen in both blood and brain throughout the ischemic event. Here, we review the work that argues a role for plasmin together with endogenous tPA or rtPA in BBB alteration, presenting the overall controversy around the topic yet creating a rational case for an involvement of plasmin in this process.
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77
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Watkins S, Robel S, Kimbrough IF, Robert SM, Ellis-Davies G, Sontheimer H. Disruption of astrocyte-vascular coupling and the blood-brain barrier by invading glioma cells. Nat Commun 2014; 5:4196. [PMID: 24943270 PMCID: PMC4127490 DOI: 10.1038/ncomms5196] [Citation(s) in RCA: 375] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 05/22/2014] [Indexed: 01/22/2023] Open
Abstract
Astrocytic endfeet cover the entire cerebral vasculature and serve as exchange sites for ions, metabolites, and energy substrates from the blood to the brain. They maintain endothelial tight junctions that form the blood-brain barrier (BBB) and release vasoactive molecules that regulate vascular tone. Malignant gliomas are highly invasive tumors that use the perivascular space for invasion and co-opt existing vessels as satellite tumors form. Here we use a clinically relevant mouse model of glioma and find that glioma cells, as they populate the perivascular space of pre-existing vessels, displace astrocytic endfeet from endothelial or vascular smooth muscle cells. This causes a focal breach in the BBB. Furthermore, astrocyte-mediated gliovascular coupling is lost, and glioma cells seize control over regulation of vascular tone through Ca2+-dependent release of K+. These findings have important clinical implications regarding blood flow in the tumor-associated brain and the ability to locally deliver chemotherapeutic drugs in disease.
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Affiliation(s)
- Stacey Watkins
- 1] Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, 1719 6th Avenue South, CIRC 425, Birmingham, Alabama 35294, USA [2]
| | - Stefanie Robel
- 1] Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, 1719 6th Avenue South, CIRC 425, Birmingham, Alabama 35294, USA [2]
| | - Ian F Kimbrough
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, 1719 6th Avenue South, CIRC 425, Birmingham, Alabama 35294, USA
| | - Stephanie M Robert
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, 1719 6th Avenue South, CIRC 425, Birmingham, Alabama 35294, USA
| | - Graham Ellis-Davies
- Department of Neuroscience, Mount Sinai School of Medicine, 1468 Madison Avenue, Annenberg Building Floor Ann22, New York, New York 10029, USA
| | - Harald Sontheimer
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, 1719 6th Avenue South, CIRC 425, Birmingham, Alabama 35294, USA
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78
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Maggio N, Itsekson Z, Ikenberg B, Strehl A, Vlachos A, Blatt I, Tanne D, Chapman J. The anticoagulant activated protein C (aPC) promotes metaplasticity in the hippocampus through an EPCR-PAR1-S1P1 receptors dependent mechanism. Hippocampus 2014; 24:1030-8. [PMID: 24753100 DOI: 10.1002/hipo.22288] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Revised: 02/23/2014] [Accepted: 04/14/2014] [Indexed: 11/08/2022]
Abstract
Thrombin and other clotting factors regulate long-term potentiation (LTP) in the hippocampus through the activation of the protease activated receptor 1 (PAR1) and consequent potentiation of N-methyl-d-aspartate receptor (NMDAR) functions. We have recently shown that the activation of PAR1 either by thrombin or the anticoagulant factor activated protein C (aPC) has differential effects on LTP. While thrombin activation of PAR1 induces an NMDAR-mediated slow onset LTP, which saturates the ability to induce further LTP in the exposed network, aPC stimulation of PAR1 enhances tetanus induced LTP through a voltage-gated calcium channels mediated mechanism. In this study, we addressed the mechanisms by which aPC enhances LTP in hippocampal slices. Using extracellular recordings, we show that a short tetanic stimulation, which does not induce LTP, is able to enhance plasticity in the presence of aPC through a mechanism that requires the activation of sphingosine-1 phosphate receptor 1 and intracellular Ca(2+) stores. These data identify aPC as a "metaplastic molecule", capable of shifting the threshold of LTP towards further potentiation. Our findings propose novel strategies to enhance plasticity in neurological diseases associated with the breakdown of the blood brain barrier and alterations in synaptic plasticity.
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Affiliation(s)
- Nicola Maggio
- Talpiot Medical Leadership Program, The Chaim Sheba Medical Center, Tel HaShomer, Israel; Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel
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79
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Salmon and human thrombin differentially regulate radicular pain, glial-induced inflammation and spinal neuronal excitability through protease-activated receptor-1. PLoS One 2013; 8:e80006. [PMID: 24278231 PMCID: PMC3835785 DOI: 10.1371/journal.pone.0080006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 10/07/2013] [Indexed: 11/22/2022] Open
Abstract
Chronic neck pain is a major problem with common causes including disc herniation and spondylosis that compress the spinal nerve roots. Cervical nerve root compression in the rat produces sustained behavioral hypersensitivity, due in part to the early upregulation of pro-inflammatory cytokines, the sustained hyperexcitability of neurons in the spinal cord and degeneration in the injured nerve root. Through its activation of the protease-activated receptor-1 (PAR1), mammalian thrombin can enhance pain and inflammation; yet at lower concentrations it is also capable of transiently attenuating pain which suggests that PAR1 activation rate may affect pain maintenance. Interestingly, salmon-derived fibrin, which contains salmon thrombin, attenuates nerve root-induced pain and inflammation, but the mechanisms of action leading to its analgesia are unknown. This study evaluates the effects of salmon thrombin on nerve root-mediated pain, axonal degeneration in the root, spinal neuronal hyperexcitability and inflammation compared to its human counterpart in the context of their enzymatic capabilities towards coagulation substrates and PAR1. Salmon thrombin significantly reduces behavioral sensitivity, preserves neuronal myelination, reduces macrophage infiltration in the injured nerve root and significantly decreases spinal neuronal hyperexcitability after painful root compression in the rat; whereas human thrombin has no effect. Unlike salmon thrombin, human thrombin upregulates the transcription of IL-1β and TNF-α and the secretion of IL-6 by cortical cultures. Salmon and human thrombins cleave human fibrinogen-derived peptides and form clots with fibrinogen with similar enzymatic activities, but salmon thrombin retains a higher enzymatic activity towards coagulation substrates in the presence of antithrombin III and hirudin compared to human thrombin. Conversely, salmon thrombin activates a PAR1-derived peptide more weakly than human thrombin. These results are the first to demonstrate that salmon thrombin has unique analgesic, neuroprotective and anti-inflammatory capabilities compared to human thrombin and that PAR1 may contribute to these actions.
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80
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Regulation of neuronal plasticity and fear by a dynamic change in PAR1-G protein coupling in the amygdala. Mol Psychiatry 2013; 18:1136-45. [PMID: 23032873 PMCID: PMC3690134 DOI: 10.1038/mp.2012.133] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Revised: 07/24/2012] [Accepted: 08/15/2012] [Indexed: 01/01/2023]
Abstract
Fear memories are acquired through neuronal plasticity, an orchestrated sequence of events regulated at circuit and cellular levels. The conventional model of fear acquisition assumes unimodal (for example, excitatory or inhibitory) roles of modulatory receptors in controlling neuronal activity and learning. Contrary to this view, we show that protease-activated receptor-1 (PAR1) promotes contrasting neuronal responses depending on the emotional status of an animal by a dynamic shift between distinct G protein-coupling partners. In the basolateral amygdala of fear-naive mice PAR1 couples to Gαq/11 and Gαo proteins, while after fear conditioning coupling to Gαo increases. Concurrently, stimulation of PAR1 before conditioning enhanced, but afterwards it inhibited firing of basal amygdala neurons. An initial impairment of the long-term potentiation (LTP) in PAR1-deficient mice was transformed into an increase in LTP and enhancement of fear after conditioning. These effects correlated with more frequent 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propanoic acid (AMPA) receptor-mediated miniature post synaptic events and increased neuronal excitability. Our findings point to experience-specific shifts in PAR1-G protein coupling in the amygdala as a novel mechanism regulating neuronal excitability and fear.
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81
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Burda JE, Radulovic M, Yoon H, Scarisbrick IA. Critical role for PAR1 in kallikrein 6-mediated oligodendrogliopathy. Glia 2013; 61:1456-70. [PMID: 23832758 DOI: 10.1002/glia.22534] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 04/28/2013] [Accepted: 05/01/2013] [Indexed: 11/10/2022]
Abstract
Kallikrein 6 (KLK6) is a secreted serine protease preferentially expressed by oligodendroglia in CNS white matter. Elevated levels of KLK6 occur in actively demyelinating multiple sclerosis (MS) lesions and in cases of spinal cord injury (SCI), stroke, and glioblastoma. Taken with recent evidence establishing KLK6 as a CNS-endogenous activator of protease-activated receptors (PARs), we hypothesized that KLK6 activates a subset of PARs to regulate oligodendrocyte physiology and potentially pathophysiology. Here, primary oligodendrocyte cultures derived from wild type or PAR1-deficient mice and the murine oligodendrocyte cell line, Oli-neu, were used to demonstrate that Klk6 (rodent form) mediates loss of oligodendrocyte processes and impedes morphological differentiation of oligodendrocyte progenitor cells (OPCs) in a PAR1-dependent fashion. Comparable gliopathy was also elicited by the canonical PAR1 agonist, thrombin, as well as PAR1-activating peptides (PAR1-APs). Klk6 also exacerbated ATP-mediated oligodendrogliopathy in vitro, pointing to a potential role in augmenting excitotoxicity. In addition, Klk6 suppressed the expression of proteolipid protein (PLP) RNA in cultured oligodendrocytes by a mechanism involving PAR1-mediated Erk1/2 signaling. Microinjection of PAR1 agonists, including Klk6 or PAR1-APs, into the dorsal column white matter of PAR1(+/+) but not PAR1(-/-) mice promoted vacuolating myelopathy and a loss of immunoreactivity for myelin basic protein (MBP) and CC-1(+) oligodendrocytes. These results demonstrate a functional role for Klk6-PAR1 signaling in oligodendroglial pathophysiology and suggest that antagonists of PAR1 or its protease agonists may represent new modalities to moderate demyelination and to promote myelin regeneration in cases of CNS white matter injury or disease.
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Affiliation(s)
- Joshua E Burda
- Neurobiology of Disease Program, Mayo Medical and Graduate School, Rochester, Minnesota, USA
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82
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Yoon H, Radulovic M, Wu J, Blaber SI, Blaber M, Fehlings MG, Scarisbrick IA. Kallikrein 6 signals through PAR1 and PAR2 to promote neuron injury and exacerbate glutamate neurotoxicity. J Neurochem 2013; 127:283-98. [PMID: 23647384 DOI: 10.1111/jnc.12293] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 04/18/2013] [Accepted: 04/29/2013] [Indexed: 01/19/2023]
Abstract
CNS trauma generates a proteolytic imbalance contributing to secondary injury, including axonopathy and neuron degeneration. Kallikrein 6 (Klk6) is a serine protease implicated in neurodegeneration, and here we investigate the role of protease-activated receptors 1 (PAR1) and PAR2 in mediating these effects. First, we demonstrate Klk6 and the prototypical activator of PAR1, thrombin, as well as PAR1 and PAR2, are each elevated in murine experimental traumatic spinal cord injury (SCI) at acute or subacute time points. Recombinant Klk6 triggered extracellular signal-regulated kinase (ERK1/2) signaling in cerebellar granule neurons and in the NSC34 spinal cord motoneuron cell line, in a phosphoinositide 3-kinae and MEK-dependent fashion. Importantly, lipopeptide inhibitors of PAR1 or PAR2, and PAR1 genetic deletion, each reduced Klk6-ERK1/2 activation. In addition, Klk6 and thrombin promoted degeneration of cerebellar neurons and exacerbated glutamate neurotoxicity. Moreover, genetic deletion of PAR1 blocked thrombin-mediated cerebellar neurotoxicity and reduced the neurotoxic effects of Klk6. Klk6 also increased glutamate-mediated Bim signaling, poly-ADP-ribose polymerase cleavage and lactate dehydrogenase release in NSC34 motoneurons and these effects were blocked by PAR1 and PAR2 lipopeptide inhibitors. Taken together, these data point to a novel Klk6-signaling axis in CNS neurons that is mediated by PAR1 and PAR2 and is positioned to contribute to neurodegeneration.
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Affiliation(s)
- Hyesook Yoon
- Neurobiology of Disease Program, Mayo Medical and Graduate School, Rochester, Minnesota, USA; Department of Physical Medicine and Rehabilitation, Mayo Medical and Graduate School, Rochester, Minnesota, USA
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83
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Dong L, Smith JR, Winkelstein BA. Ketorolac reduces spinal astrocytic activation and PAR1 expression associated with attenuation of pain after facet joint injury. J Neurotrauma 2013; 30:818-25. [PMID: 23126437 PMCID: PMC3660109 DOI: 10.1089/neu.2012.2600] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Chronic neck pain affects up to 70% of persons, with the facet joint being the most common source. Intra-articular injection of the non-steroidal anti-inflammatory drug ketorolac reduces post-operative joint-mediated pain; however, the mechanism of its attenuation of facet-mediated pain has not been evaluated. Protease-activated receptor-1 (PAR1) has differential roles in pain maintenance depending on the type and location of painful injury. This study investigated if the timing of intra-articular ketorolac injection after painful cervical facet injury affects behavioral hypersensitivity by modulating spinal astrocyte activation and/or PAR1 expression. Rats underwent a painful joint distraction and received an injection of ketorolac either immediately or 1 day later. Separate control groups included injured rats with a vehicle injection at day 1 and sham operated rats. Forepaw mechanical allodynia was measured for 7 days, and spinal cord tissue was immunolabeled for glial fibrillary acidic protein (GFAP) and PAR1 expression in the dorsal horn on day 7. Ketorolac administered on day 1 after injury significantly reduced allodynia (p=0.0006) to sham levels, whereas injection immediately after the injury had no effect compared with vehicle. Spinal astrocytic activation followed behavioral responses and was significantly decreased (p=0.009) only for ketorolac given at day 1. Spinal PAR1 (p=0.0025) and astrocytic PAR1 (p=0.012) were significantly increased after injury. Paralleling behavioral data, astrocytic PAR1 was returned to levels in sham only when ketorolac was administered on day 1. Yet, spinal PAR1 was significantly reduced (p<0.0001) by ketorolac independent of timing. Spinal astrocyte expression of PAR1 appears to be associated with the maintenance of facet-mediated pain.
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Affiliation(s)
- Ling Dong
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jenell R. Smith
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Beth A. Winkelstein
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania
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84
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Maggio N, Blatt I, Vlachos A, Tanne D, Chapman J, Segal M. Treating seizures and epilepsy with anticoagulants? Front Cell Neurosci 2013; 7:19. [PMID: 23467310 PMCID: PMC3587848 DOI: 10.3389/fncel.2013.00019] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 02/13/2013] [Indexed: 12/18/2022] Open
Abstract
Thrombin is a serine protease playing an essential role in the blood coagulation cascade. Recent work, however, has identified a novel role for thrombin-mediated signaling pathways in the central nervous system. Binding of thrombin to protease-activated receptors (PARs) in the brain appears to have multiple actions affecting both health and disease. Specifically, thrombin has been shown to lead to the onset of seizures via PAR-1 activation. In this perspective article, we review the putative mechanisms by which thrombin causes seizures and epilepsy. We propose a potential role of PAR-1 antagonists and novel thrombin inhibitors as new, possible antiepileptic drugs.
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Affiliation(s)
- Nicola Maggio
- Talpiot Medical Leadership Program, The Chaim Sheba Medical Center Tel HaShomer, Israel ; Department of Neurology, The J. Sagol Neuroscience Center, The Chaim Sheba Medical Center Tel HaShomer, Israel
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85
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Maggio N, Itsekson Z, Dominissini D, Blatt I, Amariglio N, Rechavi G, Tanne D, Chapman J. Thrombin regulation of synaptic plasticity: implications for physiology and pathology. Exp Neurol 2013; 247:595-604. [PMID: 23454608 DOI: 10.1016/j.expneurol.2013.02.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 01/24/2013] [Accepted: 02/18/2013] [Indexed: 02/03/2023]
Abstract
Thrombin, a serine protease involved in the coagulation cascade has been recently shown to affect neuronal function following blood-brain barrier breakdown. Several lines of evidence have shown that thrombin may exist in the brain parenchyma under normal physiological conditions, yet its role in normal brain functions and synaptic transmission has not been established. In an attempt to shed light on the physiological functions of thrombin and Protease Activated Receptor 1 (PAR1) in the brain, we studied the effects of thrombin and a PAR1 agonist on long term potentiation (LTP) in mice hippocampal slices. Surprisingly, different concentrations of thrombin affect LTP through different molecular routes converging on PAR1. High thrombin concentrations induced an NMDA dependent, slow onset LTP, whereas low concentrations of thrombin promoted a VGCCs, mGluR-5 dependent LTP through activated Protein C (aPC). Remarkably, aPC facilitated LTP by activating PAR1 through an Endothelial Protein C Receptor (EPCR)-mediated mechanism which involves intracellular calcium stores. These findings reveal a novel mechanism by which PAR1 may regulate the threshold for synaptic plasticity in the hippocampus and provide additional insights into the role of this receptor in normal and pathological conditions.
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Affiliation(s)
- Nicola Maggio
- Talpiot Medical Leadership Program, The Chaim Sheba Medical Center, 52621 Tel HaShomer, Israel.
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86
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Maggio N, Cavaliere C, Papa M, Blatt I, Chapman J, Segal M. Thrombin regulation of synaptic transmission: Implications for seizure onset. Neurobiol Dis 2013; 50:171-8. [DOI: 10.1016/j.nbd.2012.10.017] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 10/05/2012] [Accepted: 10/20/2012] [Indexed: 11/28/2022] Open
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87
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Plasmin Activation of Glial Cells through Protease-Activated Receptor 1. PATHOLOGY RESEARCH INTERNATIONAL 2013; 2013:314709. [PMID: 23431500 PMCID: PMC3568866 DOI: 10.1155/2013/314709] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 12/07/2012] [Indexed: 11/30/2022]
Abstract
The objective of this study was to determine whether plasmin could induce morphological changes in human glial cells via PAR1. Human glioblastoma A172 cells were cultured in the presence of plasmin or the PAR1 specific activating hexapeptide, SFLLRN. Cells were monitored by flow cytometry to detect proteolytic activation of PAR1 receptor. Morphological changes were recorded by photomicroscopy and apoptosis was measured by annexinV staining. Plasmin cleaved the PAR1 receptor on glial cells at 5 minutes (P = 0.02). After 30 minutes, cellular processes had begun to retract from the basal substratum and by 4 hours glial cells had become detached. Similar results were obtained by generating plasmin de novo from plasminogen. Morphological transformation was blocked by plasmin inhibitors aprotinin or epsilon-aminocaproic acid (P = 0.03). Cell viability was unimpaired during early morphological changes, but by 24 hours following plasmin treatment 22% of glial cells were apoptotic. PAR1 activating peptide SFLLRN (but not inactive isomer FSLLRN) promoted analogous glial cell detachment (P = 0.03), proving the role for PAR1 in this process. This study has identified a plasmin/PAR1 axis of glial cell activation, linked to changes in glial cell morophology. This adds to our understanding of pathophysiological disease mechanisms of plasmin and the plasminogen system in neuroinjury.
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88
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Channel-mediated astrocytic glutamate release via Bestrophin-1 targets synaptic NMDARs. Mol Brain 2013; 6:4. [PMID: 23324492 PMCID: PMC3577500 DOI: 10.1186/1756-6606-6-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 01/14/2013] [Indexed: 11/16/2022] Open
Abstract
Background Astrocytes regulate neuronal excitability and synaptic activity by releasing gliotransmitters such as glutamate. Our recent study demonstrated that astrocytes release glutamate upon GPCR activation via Ca2+ activated anion channel, Bestrophin-1 (Best1). The target of Best1-mediated astrocytic glutamate has been shown to be the neuronal NMDA receptors (NMDAR). However, whether it targets synaptically or extra-synaptically localized NMDAR is not known. Findings We recorded spontaneous miniature excitatory postsynaptic currents (mEPSCs) from CA1 pyramidal cells to test whether Best1-mediated astrocytic glutamate targets synaptic NMDAR. An agonist of protease activated receptor 1 (PAR1) was used to induce astrocytic Ca2+ increase and glutamate release. Firstly, we found that activation of PAR1 and subsequent release of glutamate from astrocyte does not alone increase the frequency of mEPSCs. Secondly, we found that mEPSC rise time is variable depending on the different electrotonic distances from the somatic recording site to the synaptic region where each mEPSC occurs. Two subgroups of mEPSC from CA1 pyramidal neuron by rise time were selected and analyzed. One group is fast rising mEPSCs with a rise time of 1 ~ 5 ms, representing synaptic activities arising from proximal dendrites. The other group is slowly rising mEPSCs with a rise time of 5 ~ 10 ms, representing synaptic events arising from glutamate release at synapses located in the distal dendrites. We used cell-type specific Best1 gene silencing system by Cre-loxP cleavage to dissociate the effect of neuronal and astrocytic Best1. Astrocytic Best1-mediated glutamate release by PAR1 activation did not affect decay kinetics, frequency, and amplitude of fast rising mEPSC. In contrast, PAR1 activation resulted in an NMDA receptor component to be present on slowly rising mEPSC, but did not alter frequency or amplitude. Conclusions Our results indicate that astrocytic glutamate via Best1 channel targets and activates synaptic NMDARs.
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Thrombin induces release of proinflammatory chemokines interleukin-8 and interferon-γ-induced protein-10 from cultured human fetal astrocytes. Neuroreport 2013; 24:36-40. [DOI: 10.1097/wnr.0b013e32835c1de4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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90
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Ronaldson PT, Davis TP. Blood-brain barrier integrity and glial support: mechanisms that can be targeted for novel therapeutic approaches in stroke. Curr Pharm Des 2012; 18:3624-44. [PMID: 22574987 DOI: 10.2174/138161212802002625] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/06/2012] [Indexed: 12/31/2022]
Abstract
The blood-brain barrier (BBB) is a critical regulator of brain homeostasis. Additionally, the BBB is the most significant obstacle to effective CNS drug delivery. It possesses specific charcteristics (i.e., tight junction protein complexes, influx and efflux transporters) that control permeation of circulating solutes including therapeutic agents. In order to form this "barrier," brain microvascular endothelial cells require support of adjacent astrocytes and microglia. This intricate relationship also occurs between endothelial cells and other cell types and structures of the CNS (i.e., pericytes, neurons, extracellular matrix), which implies existence of a "neurovascular unit." Ischemic stroke can disrupt the neurovascular unit at both the structural and functional level, which leads to an increase in leak across the BBB. Recent studies have identified several pathophysiological mechanisms (i.e., oxidative stress, activation of cytokine-mediated intracellular signaling systems) that mediate changes in the neurovascular unit during ischemic stroke. This review summarizes current knowledge in this area and emphasizes pathways (i.e., oxidative stress, cytokine-mediated intracellular signaling, glial-expressed receptors/targets) that can be manipulated pharmacologically for i) preservation of BBB and glial integrity during ischemic stroke and ii) control of drug permeation and/or transport across the BBB. Targeting these pathways present a novel opportunity for optimization of CNS delivery of therapeutics in the setting of ischemic stroke.
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Affiliation(s)
- Patrick T Ronaldson
- Department of Medical Pharmacology, College of Medicine, University of Arizona, 1501 North Campbell Avenue, P.O. Box 245050, Tucson, AZ 85724-5050, USA.
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91
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Woo DH, Han KS, Shim JW, Yoon BE, Kim E, Bae JY, Oh SJ, Hwang EM, Marmorstein AD, Bae YC, Park JY, Lee CJ. TREK-1 and Best1 channels mediate fast and slow glutamate release in astrocytes upon GPCR activation. Cell 2012; 151:25-40. [PMID: 23021213 DOI: 10.1016/j.cell.2012.09.005] [Citation(s) in RCA: 254] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 06/18/2012] [Accepted: 09/05/2012] [Indexed: 11/28/2022]
Abstract
Astrocytes release glutamate upon activation of various GPCRs to exert important roles in synaptic functions. However, the molecular mechanism of release has been controversial. Here, we report two kinetically distinct modes of nonvesicular, channel-mediated glutamate release. The fast mode requires activation of G(αi), dissociation of G(βγ), and subsequent opening of glutamate-permeable, two-pore domain potassium channel TREK-1 through direct interaction between G(βγ) and N terminus of TREK-1. The slow mode is Ca(2+) dependent and requires G(αq) activation and opening of glutamate-permeable, Ca(2+)-activated anion channel Best1. Ultrastructural analyses demonstrate that TREK-1 is preferentially localized at cell body and processes, whereas Best1 is mostly found in microdomains of astrocytes near synapses. Diffusion modeling predicts that the fast mode can target neuronal mGluR with peak glutamate concentration of 100 μM, whereas slow mode targets neuronal NMDA receptors at around 1 μM. Our results reveal two distinct sources of astrocytic glutamate that can differentially influence neighboring neurons.
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Affiliation(s)
- Dong Ho Woo
- Center for Neural Science, Korea Institute of Science and Technology, Seoul, Republic of Korea
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92
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STIM1 and Orai1 mediate thrombin-induced Ca2+ influx in rat cortical astrocytes. Cell Calcium 2012; 52:457-67. [DOI: 10.1016/j.ceca.2012.08.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 07/25/2012] [Accepted: 08/08/2012] [Indexed: 12/23/2022]
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93
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Almonte AG, Qadri LH, Sultan FA, Watson JA, Mount DJ, Rumbaugh G, Sweatt JD. Protease-activated receptor-1 modulates hippocampal memory formation and synaptic plasticity. J Neurochem 2012; 124:109-22. [PMID: 23113835 DOI: 10.1111/jnc.12075] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 09/21/2012] [Accepted: 10/22/2012] [Indexed: 11/28/2022]
Abstract
Protease-activated receptor-1 (PAR1) is an unusual G-protein coupled receptor (GPCR) that is activated through proteolytic cleavage by extracellular serine proteases. Although previous work has shown that inhibiting PAR1 activation is neuroprotective in models of ischemia, traumatic injury, and neurotoxicity, surprisingly little is known about PAR1's contribution to normal brain function. Here, we used PAR1-/- mice to investigate the contribution of PAR1 function to memory formation and synaptic function. We demonstrate that PAR1-/- mice have deficits in hippocampus-dependent memory. We also show that while PAR1-/- mice have normal baseline synaptic transmission at Schaffer collateral-CA1 synapses, they exhibit severe deficits in N-methyl-d-aspartate receptor (NMDAR)-dependent long-term potentiation (LTP). Mounting evidence indicates that activation of PAR1 leads to potentiation of NMDAR-mediated responses in CA1 pyramidal cells. Taken together, this evidence and our data suggest an important role for PAR1 function in NMDAR-dependent processes subserving memory formation and synaptic plasticity.
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Affiliation(s)
- Antoine G Almonte
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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94
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Oh SJ, Han KS, Park H, Woo DH, Kim HY, Traynelis SF, Lee CJ. Protease activated receptor 1-induced glutamate release in cultured astrocytes is mediated by Bestrophin-1 channel but not by vesicular exocytosis. Mol Brain 2012; 5:38. [PMID: 23062602 PMCID: PMC3539998 DOI: 10.1186/1756-6606-5-38] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 10/09/2012] [Indexed: 11/27/2022] Open
Abstract
Background Glutamate is the major transmitter that mediates the principal form of excitatory synaptic transmission in the brain. It has been well established that glutamate is released via Ca2+-dependent exocytosis of glutamate-containing vesicles in neurons. However, whether astrocytes exocytose to release glutamate under physiological condition is still unclear. Findings We report a novel form of glutamate release in astrocytes via the recently characterized Ca2+-activated anion channel, Bestrophin-1 (Best1) by Ca2+ dependent mechanism through the channel pore. We demonstrate that upon activation of protease activated receptor 1 (PAR1), an increase in intracellular Ca2+ concentration leads to an opening of Best1 channels and subsequent release of glutamate in cultured astrocytes. Conclusions These results provide strong molecular evidence for potential astrocyte-neuron interaction via Best1-mediated glutamate release.
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Affiliation(s)
- Soo-Jin Oh
- Korea Institute of Science and Technology, Seoul, South Korea
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95
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Scarisbrick IA, Radulovic M, Burda JE, Larson N, Blaber SI, Giannini C, Blaber M, Vandell AG. Kallikrein 6 is a novel molecular trigger of reactive astrogliosis. Biol Chem 2012; 393:355-67. [PMID: 22505518 DOI: 10.1515/hsz-2011-0241] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 01/20/2012] [Indexed: 01/02/2023]
Abstract
Kallikrein-related peptidase 6 (KLK6) is a trypsin-like serine protease upregulated at sites of central nervous system (CNS) injury, including de novo expression by reactive astrocytes, yet its physiological actions are largely undefined. Taken with recent evidence that KLK6 activates G-protein-coupled protease-activated receptors (PARs), we hypothesized that injury-induced elevations in KLK6 contribute to the development of astrogliosis and that this occurs in a PAR-dependent fashion. Using primary murine astrocytes and the Neu7 astrocyte cell line, we show that KLK6 causes astrocytes to transform from an epitheliod to a stellate morphology and to secrete interleukin 6 (IL-6). By contrast, KLK6 reduced expression of glial fibrillary acidic protein (GFAP). The stellation-promoting activities of KLK6 were shown to be dependent on activation of the thrombin receptor, PAR1, as a PAR1-specific inhibitor, SCH79797, blocked KLK6-induced morphological changes. The ability of KLK6 to promote astrocyte stellation was also shown to be linked to activation of protein kinase C (PKC). These studies indicate that KLK6 is positioned to serve as a molecular trigger of select physiological processes involved in the development of astrogliosis and that this is likely to occur at least in part by activation of the G-protein-coupled receptor, PAR1.
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Affiliation(s)
- Isobel A Scarisbrick
- Neurobiology of Disease Program, Mayo Medical and Graduate School, Rochester, MN 55905, USA.
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96
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Zhang J, Wang Y, Zhu P, Wang X, Lv M, Feng H. siRNA-mediated silence of protease-activated receptor-1 minimizes ischemic injury of cerebral cortex through HSP70 and MAP2. J Neurol Sci 2012; 320:6-11. [PMID: 22831762 DOI: 10.1016/j.jns.2012.05.040] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 04/21/2012] [Accepted: 05/15/2012] [Indexed: 12/15/2022]
Abstract
Cerebral ischemic stroke is a prevalent disease in senior individuals. The anticoagulation and thrombolysis to recover blood supply as well as the diminution of neural excitotoxicity to protect brain cells have not shown to fully improve stroke patients. The comprehensive mechanisms and medication specificity remain to be addressed. The silence of specific mRNAs by RNA interference provides revenues for such goals. We examined whether the silence of protease-activated receptor-1 (PAR-1) by siRNA protects brain tissues from ischemic injury. In three groups of Wistar rats, their lateral ventricles received the injections of lentiviral vectors carrying siRNA for PAR1, small RNA in mismatching PAR1 or saline. A week after the injections, these rats were treated by one side of middle cerebral artery occlusion (MCAO). The scores of neurological deficits, the volume of ischemic infarction and the expressions of PAR-1, HSP-70 and MAP-2 were measured in 24h of MCAO. Our results show that the silence of PAR-1 significantly reduces neurological deficits and infarction volume, as well as elevates HSP-70 and MAP-2 expressions. Thus, the knock-down of PAR1 minimizes the ischemic impairments of cerebral cortex via HSP70 and MAP-2 pathways.
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Affiliation(s)
- Jun Zhang
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang Province, PR China
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97
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Abstract
Memory consolidation in a discriminative bead pecking task is modulated by endogenous adenosine triphosphate (ATP) acting at purinergic receptors in the hippocampus. Consolidation, from short- to intermediate- to long-term memory during two distinct periods following training, was blocked by the non-selective P2 purinergic receptor antagonist PPADS (pyridoxal phosphate-6-azo(benzene-2,4-disulphonic acid) tetrasodium salt hydrate and the specific P2Y1 receptor antagonist MRS2179. Direct injections of the ATP agonists (ATPγS and ADPβS) potentiated memory consolidation and the effect of ADPβS was blocked by MRS2179, suggesting an important role of ATP on memory consolidation via the P2Y1 receptor in the chick hippocampus. Incubation of astrocytes with ATPγS and ADPβS resulted in the increase of intracellular calcium ([Ca2+]i), the latter being blocked by MRS2179 suggesting a specific role for P2Y1 receptors in the calcium response. This response was prevented by blocking astrocytic oxidative metabolism with fluoroacetate. We argue that the source of the ATP acting on neuronal P2Y1 receptors is most likely to be astrocytes. Thrombin selectively increases [Ca2+]i in astrocytes but not in neurones. The main findings of the present study are: (a) astrocytic [Ca2+]i plays an important role in the consolidation of short-term to long-term memory; and (b) ATP released from chick astrocytes during learning modulates neuronal activity through astrocytic P2Y1 receptors.
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98
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Carmignoto G, Haydon PG. Astrocyte calcium signaling and epilepsy. Glia 2012; 60:1227-33. [PMID: 22389222 DOI: 10.1002/glia.22318] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 02/09/2012] [Accepted: 02/13/2012] [Indexed: 12/31/2022]
Abstract
Studies performed over the last decade, in both animal models and human epilepsy, support the view that a defective K(+) buffering due to an altered expression of K(+) and aquaporin channels in astrocytes represents a possible causative factor of the pathological neuronal hyperexcitability in the epileptic brain. More recent studies, however, reappraised the role of neurons in epileptogenesis and suggested that Ca(2+)-dependent gliotransmission directly contributes to the excessive neuronal synchronization that predisposes the brain network to seizures. Significant support for this view comes from the finding that astrocytes from hyperexcitable networks respond to neuronal signals with massive Ca(2+) elevations and generate a recurrent excitatory loop with neurons that has the potential to promote a focal seizure. The specific aim of this review is on the one hand, to provide an overview of the experimental findings that hinted at a direct role of Ca(2+)-dependent gliotransmission in the generation of seizure-like discharges in models of focal epilepsy; and on the other hand, to emphasize the importance of developing new experimental tools that could help us to understand the amazing complexity of neuron-astrocyte partnership in brain disorders.
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Affiliation(s)
- Giorgio Carmignoto
- Institute of Neuroscience of the National Research Council and Department of Experimental Biomedical Sciences, University of Padova, Viale G. Colombo 3, Padova, Italy.
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99
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Xiong Q, Ancona N, Hauser ER, Mukherjee S, Furey TS. Integrating genetic and gene expression evidence into genome-wide association analysis of gene sets. Genome Res 2012; 22:386-97. [PMID: 21940837 PMCID: PMC3266045 DOI: 10.1101/gr.124370.111] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 09/19/2011] [Indexed: 12/11/2022]
Abstract
Single variant or single gene analyses generally account for only a small proportion of the phenotypic variation in complex traits. Alternatively, gene set or pathway association analyses are playing an increasingly important role in uncovering genetic architectures of complex traits through the identification of systematic genetic interactions. Two dominant paradigms for gene set analyses are association analyses based on SNP genotypes and those based on gene expression profiles. However, gene-disease association can manifest in many ways, such as alterations of gene expression, genotype, and copy number; thus, an integrative approach combining multiple forms of evidence can more accurately and comprehensively capture pathway associations. We have developed a single statistical framework, Gene Set Association Analysis (GSAA), that simultaneously measures genome-wide patterns of genetic variation and gene expression variation to identify sets of genes enriched for differential expression and/or trait-associated genetic markers. Simulation studies illustrate that joint analyses of genomic data increase the power to detect real associations when compared with gene set methods that use only one genomic data type. The analysis of two human diseases, glioblastoma and Crohn's disease, detected abnormalities in previously identified disease-associated pathways, such as pathways related to PI3K signaling, DNA damage response, and the activation of NFKB. In addition, GSAA predicted novel pathway associations, for example, differential genetic and expression characteristics in genes from the ABC transporter family in glioblastoma and from the HLA system in Crohn's disease. These demonstrate that GSAA can help uncover biological pathways underlying human diseases and complex traits.
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Affiliation(s)
- Qing Xiong
- Department of Genetics, Department of Biology, Lineberger Comprehensive Cancer Center, and Carolina Center for Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Nicola Ancona
- Institute of Intelligent Systems for Automation National Research Council, Bari IT 70126, Italy
| | - Elizabeth R. Hauser
- Center for Human Genetics and Section of Medical Genetics, Department of Medicine, Duke University, Durham, North Carolina 27710, USA
| | - Sayan Mukherjee
- Departments of Statistical Science, Computer Science, and Mathematics, Institute for Genome Sciences & Policy, Duke University, Durham, North Carolina 27708, USA
| | - Terrence S. Furey
- Department of Genetics, Department of Biology, Lineberger Comprehensive Cancer Center, and Carolina Center for Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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100
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McCoy KL, Gyoneva S, Vellano CP, Smrcka AV, Traynelis SF, Hepler JR. Protease-activated receptor 1 (PAR1) coupling to G(q/11) but not to G(i/o) or G(12/13) is mediated by discrete amino acids within the receptor second intracellular loop. Cell Signal 2012; 24:1351-60. [PMID: 22306780 DOI: 10.1016/j.cellsig.2012.01.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Revised: 12/27/2011] [Accepted: 01/19/2012] [Indexed: 12/29/2022]
Abstract
Protease-activated receptor 1 (PAR1) is an unusual GPCR that interacts with multiple G protein subfamilies (G(q/11), G(i/o), and G(12/13)) and their linked signaling pathways to regulate a broad range of pathophysiological processes. However, the molecular mechanisms whereby PAR1 interacts with multiple G proteins are not well understood. Whether PAR1 interacts with various G proteins at the same, different, or overlapping binding sites is not known. Here we investigated the functional and specific binding interactions between PAR1 and representative members of the G(q/11), G(i/o), and G(12/13) subfamilies. We report that G(q/11) physically and functionally interacts with specific amino acids within the second intracellular (i2) loop of PAR1. We identified five amino acids within the PAR1 i2 loop that, when mutated individually, each markedly reduced PAR1 activation of linked inositol phosphate formation in transfected COS-7 cells (functional PAR1-null cells). Among these mutations, only R205A completely abolished direct G(q/11) binding to PAR1 and also PAR1-directed inositol phosphate and calcium mobilization in COS-7 cells and PAR1-/- primary astrocytes. In stark contrast, none of the PAR1 i2 loop mutations disrupted direct PAR1 binding to either G(o) or G(12), or their functional coupling to linked pertussis toxin-sensitive ERK phosphorylation and C3 toxin-sensitive Rho activation, respectively. In astrocytes, our findings suggest that PAR1-directed calcium signaling involves a newly appreciated G(q/11)-PLCε pathway. In summary, we have identified key molecular determinants for PAR1 interactions with G(q/11), and our findings support a model where G(q/11), G(i/o) or G(12/13) each bind to distinct sites within the cytoplasmic regions of PAR1.
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Affiliation(s)
- Kelly L McCoy
- Department of Pharmacology, O. Wayne Rollins Research Center, Emory University School of Medicine, Atlanta, GA 30322, USA
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