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Kim S, Sharma C, Jung UJ, Kim SR. Pathophysiological Role of Microglial Activation Induced by Blood-Borne Proteins in Alzheimer's Disease. Biomedicines 2023; 11:biomedicines11051383. [PMID: 37239054 DOI: 10.3390/biomedicines11051383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/01/2023] [Accepted: 05/04/2023] [Indexed: 05/28/2023] Open
Abstract
The blood-brain barrier (BBB) restricts entry of neurotoxic plasma components, blood cells, and pathogens into the brain, leading to proper neuronal functioning. BBB impairment leads to blood-borne protein infiltration such as prothrombin, thrombin, prothrombin kringle-2, fibrinogen, fibrin, and other harmful substances. Thus, microglial activation and release of pro-inflammatory mediators commence, resulting in neuronal damage and leading to impaired cognition via neuroinflammatory responses, which are important features observed in the brain of Alzheimer's disease (AD) patients. Moreover, these blood-borne proteins cluster with the amyloid beta plaque in the brain, exacerbating microglial activation, neuroinflammation, tau phosphorylation, and oxidative stress. These mechanisms work in concert and reinforce each other, contributing to the typical pathological changes in AD in the brain. Therefore, the identification of blood-borne proteins and the mechanisms involved in microglial activation and neuroinflammatory damage can be a promising therapeutic strategy for AD prevention. In this article, we review the current knowledge regarding the mechanisms of microglial activation-mediated neuroinflammation caused by the influx of blood-borne proteins into the brain via BBB disruption. Subsequently, the mechanisms of drugs that inhibit blood-borne proteins, as a potential therapeutic approach for AD, along with the limitations and potential challenges of these approaches, are also summarized.
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Affiliation(s)
- Sehwan Kim
- School of Life Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
- Brain Science and Engineering Institute, Kyungpook National University, Daegu 41944, Republic of Korea
| | - Chanchal Sharma
- School of Life Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
- BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Un Ju Jung
- Department of Food Science and Nutrition, Pukyong National University, Busan 48513, Republic of Korea
| | - Sang Ryong Kim
- School of Life Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
- Brain Science and Engineering Institute, Kyungpook National University, Daegu 41944, Republic of Korea
- BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea
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Gu YH, Hawkins BT, Izawa Y, Yoshikawa Y, Koziol JA, Del Zoppo GJ. Intracerebral hemorrhage and thrombin-induced alterations in cerebral microvessel matrix. J Cereb Blood Flow Metab 2022; 42:1732-1747. [PMID: 35510668 PMCID: PMC9441730 DOI: 10.1177/0271678x221099092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Four phase III clinical trials of oral direct factor Xa or thrombin inhibitors demonstrated significantly lower intracranial hemorrhage compared to warfarin in patients with nonvalvular-atrial fibrillation. This is counter-intuitive to the principle that inhibiting thrombosis should increase hemorrhagic risk. We tested the novel hypothesis that anti-thrombin activity decreases the risk of intracerebral hemorrhage by directly inhibiting thrombin-mediated degradation of cerebral microvessel basal lamina matrix, responsible for preventing hemorrhage. Collagen IV, laminin, and perlecan each contain one or more copies of the unique α-thrombin cleavage site consensus sequence. In blinded controlled experiments, α-thrombin significantly degraded each matrix protein in vitro and in vivo in a concentration-dependent fashion. In vivo stereotaxic injection of α-thrombin significantly increased permeability, local IgG extravasation, and hemoglobin (Hgb) deposition together with microvessel matrix degradation in a mouse model. In all formats the direct anti-thrombin dabigatran completely inhibited matrix degradation by α-thrombin. Fourteen-day oral exposure to dabigatran etexilate-containing chow completely inhibited matrix degradation, the permeability to large molecules, and cerebral hemorrhage associated with α-thrombin. These experiments demonstrate that thrombin can degrade microvessel matrix, leading to hemorrhage, and that inhibition of microvessel matrix degradation by α-thrombin decreases cerebral hemorrhage. Implications for focal ischemia and other conditions are discussed.
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Affiliation(s)
- Yu-Huan Gu
- Division of Hematology, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - Brian T Hawkins
- Division of Hematology, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.,Duke University Center for WaSH-AID, Department of Eklectrical and Computer Engineering, Duke University, Durham, NC, USA
| | - Yoshikane Izawa
- Division of Hematology, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.,Department of Neurology, Keio University School of Medicine, Tokyo, Japan
| | - Yoji Yoshikawa
- Division of Hematology, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - James A Koziol
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA, USA
| | - Gregory J Del Zoppo
- Division of Hematology, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.,Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
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Jeon MT, Kim KS, Kim ES, Lee S, Kim J, Hoe HS, Kim DG. Emerging pathogenic role of peripheral blood factors following BBB disruption in neurodegenerative disease. Ageing Res Rev 2021; 68:101333. [PMID: 33774194 DOI: 10.1016/j.arr.2021.101333] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 03/03/2021] [Accepted: 03/19/2021] [Indexed: 12/15/2022]
Abstract
The responses of central nervous system (CNS) cells such as neurons and glia in neurodegenerative diseases (NDs) suggest that regulation of neuronal and glial functions could be a strategy for ND prevention and/or treatment. However, attempts to develop such therapeutics for NDs have been hindered by the challenge of blood-brain barrier (BBB) permeability and continued constitutive neuronal loss. These limitations indicate the need for additional perspectives for the prevention/treatment of NDs. In particular, the disruption of the blood-brain barrier (BBB) that accompanies NDs allows brain infiltration by peripheral factors, which may stimulate innate immune responses involved in the progression of neurodegeneration. The accumulation of blood factors like thrombin, fibrinogen, c-reactive protein (CRP) and complement components in the brain has been observed in NDs and may activate the innate immune system in the CNS. Thus, strengthening the integrity of the BBB may enhance its protective role to attenuate ND progression and functional loss. In this review, we describe the innate immune system in the CNS and the contribution of blood factors to the role of the CNS immune system in neurodegeneration and neuroprotection.
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Affiliation(s)
- Min-Tae Jeon
- Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu, 41062, Republic of Korea
| | - Kyu-Sung Kim
- Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu, 41062, Republic of Korea; Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), 333, Techno jungang-daero, Hyeonpung-eup, Dalseong-gun, Daegu, 42988, Republic of Korea
| | - Eun Seon Kim
- Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu, 41062, Republic of Korea; Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), 333, Techno jungang-daero, Hyeonpung-eup, Dalseong-gun, Daegu, 42988, Republic of Korea
| | - Suji Lee
- Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu, 41062, Republic of Korea; Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, 16 De Crespigny Park, London, SE5 8AF, UK
| | - Jieun Kim
- Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu, 41062, Republic of Korea
| | - Hyang-Sook Hoe
- Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu, 41062, Republic of Korea; Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), 333, Techno jungang-daero, Hyeonpung-eup, Dalseong-gun, Daegu, 42988, Republic of Korea.
| | - Do-Geun Kim
- Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu, 41062, Republic of Korea.
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Leem E, Jeong KH, Won SY, Shin WH, Kim SR. Prothrombin Kringle-2: A Potential Inflammatory Pathogen in the Parkinsonian Dopaminergic System. Exp Neurobiol 2016; 25:147-55. [PMID: 27574481 PMCID: PMC4999420 DOI: 10.5607/en.2016.25.4.147] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 07/29/2016] [Accepted: 07/30/2016] [Indexed: 01/04/2023] Open
Abstract
Although accumulating evidence suggests that microglia-mediated neuroinflammation may be crucial for the initiation and progression of Parkinson's disease (PD), and that the control of neuroinflammation may be a useful strategy for preventing the degeneration of nigrostriatal dopaminergic (DA) projections in the adult brain, it is still unclear what kinds of endogenous biomolecules initiate microglial activation, consequently resulting in neurodegeneration. Recently, we reported that the increase in the levels of prothrombin kringle-2 (pKr-2), which is a domain of prothrombin that is generated by active thrombin, can lead to disruption of the nigrostriatal DA projection. This disruption is mediated by neurotoxic inflammatory events via the induction of microglial Toll-like receptor 4 (TLR4) in vivo , thereby resulting in less neurotoxicity in TLR4-deficient mice. Moreover, inhibition of microglial activation following minocycline treatment, which has anti-inflammatory activity, protects DA neurons from pKr-2-induced neurotoxicity in the substantia nigra (SN) in vivo. We also found that the levels of pKr-2 and microglial TLR4 were significantly increased in the SN of PD patients compared to those of age-matched controls. These observations suggest that there may be a correlation between pKr-2 and microglial TLR4 in the initiation and progression of PD, and that inhibition of pKr-2-induced microglial activation may be protective against the degeneration of the nigrostriatal DA system in vivo. To describe the significance of pKr-2 overexpression, which may have a role in the pathogenesis of PD, we have reviewed the mechanisms of pKr-2-induced microglial activation, which results in neurodegeneration in the SN of the adult brain.
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Affiliation(s)
- Eunju Leem
- School of Life Sciences & Biotechnology, Kyungpook National University, Daegu 41566, Korea.; BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Korea
| | - Kyoung Hoon Jeong
- School of Life Sciences & Biotechnology, Kyungpook National University, Daegu 41566, Korea.; BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Korea
| | - So-Yoon Won
- Department of Biochemistry and Signaling Disorder Research Center, College of Medicine, Chungbuk National University, Cheongju 28644, Korea
| | - Won-Ho Shin
- Predictive Research Center, Korea Institute of Toxicology, Daejeon 34114, Korea
| | - Sang Ryong Kim
- School of Life Sciences & Biotechnology, Kyungpook National University, Daegu 41566, Korea.; BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Korea.; Institute of Life Science & Biotechnology, Kyungpook National University, Daegu 41566, Korea.; Brain Science and Engineering Institute, Kyungpook National University, Daegu 41944, Korea
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Cho KS, Lee EJ, Kim JN, Choi JW, Kim HY, Han SH, Ryu JH, Cheong JH, Shin CY, Kwon KJ. Proteinase 3 Induces Neuronal Cell Death Through Microglial Activation. Neurochem Res 2015; 40:2242-51. [PMID: 26349766 DOI: 10.1007/s11064-015-1714-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 07/30/2015] [Accepted: 08/28/2015] [Indexed: 01/29/2023]
Abstract
Proteinase 3 (PR3) is released from neutrophil granules and is involved in the inflammatory process. PR3 is implicated in antimicrobial defense and cell death, but the exact role of PR3 in the brain is less defined. Microglia is the major immune effector cells in the CNS and is activated by brain injury. In the present study, the effect of PR3 on glial activation was investigated. Microglial activation was assessed by the intracellular level of reactive oxygen species and expression of inflammatory cytokines. The conditioned media from activated microglia by PR3 was used for measuring the neurotoxic effects of PR3-stimulated microglia. The effects of PR3 in vivo were measured by microinjecting PR3 into the rat brain. Herein we show that PR3 increased the inflammatory responses including the intracellular ROS and pro-inflammatory cytokine production in rat primary microglia. Conditioned media from PR3-treated microglia induced neuronal cell death in a concentration dependent manner. Furthermore, microinjected PR3 into the striatum of the rat brain induced microglial activation and neuronal cell death. Interestingly treatment with anti-PR3 monoclonal antibody and protease inhibitors ameliorated microglial activation induced by PR3 in primary microglia and striatum, which also prevented neuronal cell death in both conditions. The data presented here suggest that PR3 is a direct modulator of microglial activation and causes neuronal death through the augmentation of inflammatory responses. We suggest that PR3 could be a new modulator of neuroinflammation, and blocking PR3 would be a promising novel therapeutic target for neuroinflammatory disease such as stroke and Alzheimer's disease.
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Affiliation(s)
- Kyu Suk Cho
- Department of Neuroscience, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, Korea
| | - Eun Joo Lee
- Department of Neuroscience, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, Korea
| | - Jung Nam Kim
- Department of Neuroscience, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, Korea
| | - Ji Woong Choi
- Department of Pharmacology, College of Pharmacy, Gachon University, Incheon, Korea
| | - Hahn Young Kim
- Department of Neuroscience, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, Korea.,Department of Neurology, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, Seoul, Korea
| | - Seol-Heui Han
- Department of Neuroscience, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, Korea.,Department of Neurology, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, Seoul, Korea
| | - Jong Hoon Ryu
- Department of Oriental Pharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul, Korea
| | - Jae Hoon Cheong
- Department of Pharmacy, College of Pharmacy, Sahmyook University, Seoul, Korea
| | - Chan Young Shin
- Department of Neuroscience, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, Korea
| | - Kyoung Ja Kwon
- Department of Neuroscience, Center for Neuroscience Research, Institute of Biomedical Science and Technology, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, Korea.
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6
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Woo JH, Lee JH, Kim H, Park SJ, Joe EH, Jou I. Control of Inflammatory Responses: a New Paradigm for the Treatment of Chronic Neuronal Diseases. Exp Neurobiol 2015; 24:95-102. [PMID: 26113788 PMCID: PMC4479815 DOI: 10.5607/en.2015.24.2.95] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/30/2015] [Accepted: 04/30/2015] [Indexed: 12/26/2022] Open
Abstract
The term 'inflammation' was first introduced by Celsus almost 2000 years ago. Biological and medical researchers have shown increasing interest in inflammation over the past few decades, in part due to the emerging burden of chronic and degenerative diseases resulting from the increased longevity that has arisen thanks to modern medicine. Inflammation is believed to play critical roles in the pathogenesis of degenerative brain diseases, including Alzheimer's disease and Parkinson's disease. Accordingly, researchers have sought to combat such diseases by controlling inflammatory responses. In this review, we describe the endogenous inflammatory stimulators and signaling pathways in the brain. In particular, our group has focused on the JAK-STAT pathway, identifying anti-inflammatory targets and testing the effects of various anti-inflammatory drugs. This work has shown that the JAK-STAT pathway and its downstream are negatively regulated by phosphatases (SHP2 and MKP-1), inhibitory proteins (SOCS1 and SOCS3) and a nuclear receptor (LXR). These negative regulators are controlled at various levels (e.g. transcriptional, post-transcriptional and post-translational). Future study of these proteins could facilitate the manipulation of the inflammatory response, which plays ubiquitous, diverse and ambivalent roles under physiological and pathological conditions.
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Affiliation(s)
- Joo Hong Woo
- Department of Pharmacology, and Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 443-721, Korea
| | - Jee Hoon Lee
- Department of Pharmacology, and Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 443-721, Korea
| | - Hyunmi Kim
- Department of Pharmacology, and Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 443-721, Korea. ; Department of Biomedical Sciences, Ajou University School of Medicine, Suwon 443-721, Korea
| | - Soo Jung Park
- Department of Pharmacology, and Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 443-721, Korea
| | - Eun-Hye Joe
- Department of Pharmacology, and Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 443-721, Korea. ; Department of Biomedical Sciences, Ajou University School of Medicine, Suwon 443-721, Korea
| | - Ilo Jou
- Department of Pharmacology, and Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 443-721, Korea. ; Department of Biomedical Sciences, Ajou University School of Medicine, Suwon 443-721, Korea
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Won SY, Kim SR, Maeng S, Jin BK. Interleukin-13/Interleukin-4-induced oxidative stress contributes to death of prothrombinkringle-2 (pKr-2)-activated microglia. J Neuroimmunol 2013; 265:36-42. [PMID: 24090651 DOI: 10.1016/j.jneuroim.2013.09.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 09/12/2013] [Accepted: 09/14/2013] [Indexed: 01/28/2023]
Abstract
The present study examined whether Interleukin-13 (IL-13) or IL-4, an anti-inflammatory cytokine, could induce cell death of activated microglia by prothrombin kringle-2 (pKr-2) which is a domain of prothrombin distinct from thrombin. Microglia cell death was detected at eight days after co-treatment of pKr-2 with IL-13/IL-4 in vitro. This cell death was assessed by live assay, dead assay, TUNEL and MTT assay. In parallel, reactive oxygen species (ROS) production was evident as assessed by superoxide assay, WST-1 and analyzing DCF in combination of pKr-2 and IL-13 or IL-4 treated microglia. The IL-13/IL-4-enhanced ROS production and cell death in pKr-2 activated microglia was partially inhibited by an NADPH oxidase inhibitor, apocynin and/or by several antioxidants. Moreover, Western blot analysis showed a significant increase in cyclooxygenase-2 (COX-2) expression in combination of pKr-2 and IL-13 or IL-4 treated microglia, which was partially inhibited by apocynin and an antioxidant, trolox. Additional studies demonstrated that microglia cell death was reversed by treatment with COX-2 inhibitor, NS398. Our data strongly suggest that oxidative stress and COX-2 activation through NADPH oxidase may contribute to IL-13/IL-4 induced cell death of pKr-2 activated microglia.
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Affiliation(s)
- So-Yoon Won
- Department of Biochemistry and Medical Research Center, Chungbuk National University College of Medicine, Cheongju 361-763, South Korea
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8
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The controversial role of microglia in malignant gliomas. Clin Dev Immunol 2013; 2013:285246. [PMID: 23983766 PMCID: PMC3741958 DOI: 10.1155/2013/285246] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 06/19/2013] [Indexed: 01/01/2023]
Abstract
Malignant gliomas contain stroma and a variety of immune cells including abundant activated microglia/macrophages. Mounting evidence indicates that the glioma microenvironment converts the glioma-associated microglia/macrophages (GAMs) into glioma-supportive, immunosuppressive cells; however, GAMs can retain intrinsic anti-tumor properties. Here, we review and discuss this duality and the potential therapeutic strategies that may inhibit their glioma-supportive and propagating functions.
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Jeong HK, Ji K, Min K, Joe EH. Brain inflammation and microglia: facts and misconceptions. Exp Neurobiol 2013; 22:59-67. [PMID: 23833554 PMCID: PMC3699675 DOI: 10.5607/en.2013.22.2.59] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 06/17/2013] [Accepted: 06/17/2013] [Indexed: 11/19/2022] Open
Abstract
THE INFLAMMATION THAT ACCOMPANIES ACUTE INJURY HAS DUAL FUNCTIONS: bactericidal action and repair. Bactericidal functions protect damaged tissue from infection, and repair functions are initiated to aid in the recovery of damaged tissue. Brain injury is somewhat different from injuries in other tissues in two respects. First, many cases of brain injury are not accompanied by infection: there is no chance of pathogens to enter in ischemia or even in traumatic injury if the skull is intact. Second, neurons are rarely regenerated once damaged. This raises the question of whether bactericidal inflammation really occurs in the injured brain; if so, how is this type of inflammation controlled? Many brain inflammation studies have been conducted using cultured microglia (brain macrophages). Even where animal models have been used, the behavior of microglia and neurons has typically been analyzed at or after the time of neuronal death, a time window that excludes the inflammatory response, which begins immediately after the injury. Therefore, to understand the patterns and roles of brain inflammation in the injured brain, it is necessary to analyze the behavior of all cell types in the injured brain immediately after the onset of injury. Based on our experience with both in vitro and in vivo experimental models of brain inflammation, we concluded that not only microglia, but also astrocytes, blood inflammatory cells, and even neurons participate and/or regulate brain inflammation in the injured brain. Furthermore, brain inflammation played by these cells protects neurons and repairs damaged microenvironment but not induces neuronal damage.
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Affiliation(s)
- Hey-Kyeong Jeong
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon 442-721, Korea. ; Department of Pharmacology, Ajou University School of Medicine, Suwon 442-721, Korea. ; Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 442-721, Korea. ; National Research Lab of Brain Inflammation, Ajou University School of Medicine, Suwon 442-721, Korea
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Babu R, Bagley JH, Di C, Friedman AH, Adamson C. Thrombin and hemin as central factors in the mechanisms of intracerebral hemorrhage-induced secondary brain injury and as potential targets for intervention. Neurosurg Focus 2012; 32:E8. [PMID: 22463118 DOI: 10.3171/2012.1.focus11366] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Intracerebral hemorrhage (ICH) is a subtype of stoke that may cause significant morbidity and mortality. Brain injury due to ICH initially occurs within the first few hours as a result of mass effect due to hematoma formation. However, there is increasing interest in the mechanisms of secondary brain injury as many patients continue to deteriorate clinically despite no signs of rehemorrhage or hematoma expansion. This continued insult after primary hemorrhage is believed to be mediated by the cytotoxic, excitotoxic, oxidative, and inflammatory effects of intraparenchymal blood. The main factors responsible for this injury are thrombin and erythrocyte contents such as hemoglobin. Therapies including thrombin inhibitors, N-methyl-D-aspartate antagonists, chelators to bind free iron, and antiinflammatory drugs are currently under investigation for reducing this secondary brain injury. This review will discuss the molecular mechanisms of brain injury as a result of intraparenchymal blood, potential targets for therapeutic intervention, and treatment strategies currently in development.
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Affiliation(s)
- Ranjith Babu
- Division of Neurosurgery, Department of Surgery, Duke University Medical Center, Durham, NC, USA
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Kim B, Yang MS, Choi D, Kim JH, Kim HS, Seol W, Choi S, Jou I, Kim EY, Joe EH. Impaired inflammatory responses in murine Lrrk2-knockdown brain microglia. PLoS One 2012; 7:e34693. [PMID: 22496842 PMCID: PMC3322140 DOI: 10.1371/journal.pone.0034693] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2011] [Accepted: 03/05/2012] [Indexed: 12/18/2022] Open
Abstract
LRRK2, a Parkinson's disease associated gene, is highly expressed in microglia in addition to neurons; however, its function in microglia has not been evaluated. Using Lrrk2 knockdown (Lrrk2-KD) murine microglia prepared by lentiviral-mediated transfer of Lrrk2-specific small inhibitory hairpin RNA (shRNA), we found that Lrrk2 deficiency attenuated lipopolysaccharide (LPS)-induced mRNA and/or protein expression of inducible nitric oxide synthase, TNF-α, IL-1β and IL-6. LPS-induced phosphorylation of p38 mitogen-activated protein kinase and stimulation of NF-κB-responsive luciferase reporter activity was also decreased in Lrrk2-KD cells. Interestingly, the decrease in NF-κB transcriptional activity measured by luciferase assays appeared to reflect increased binding of the inhibitory NF-κB homodimer, p50/p50, to DNA. In LPS-responsive HEK293T cells, overexpression of the human LRRK2 pathologic, kinase-active mutant G2019S increased basal and LPS-induced levels of phosphorylated p38 and JNK, whereas wild-type and other pathologic (R1441C and G2385R) or artificial kinase-dead (D1994A) LRRK2 mutants either enhanced or did not change basal and LPS-induced p38 and JNK phosphorylation levels. However, wild-type LRRK2 and all LRRK2 mutant variants equally enhanced NF-κB transcriptional activity. Taken together, these results suggest that LRRK2 is a positive regulator of inflammation in murine microglia, and LRRK2 mutations may alter the microenvironment of the brain to favor neuroinflammation.
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Affiliation(s)
- Beomsue Kim
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea
| | - Myung-Soon Yang
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea
| | - Dongjoo Choi
- Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Korea
| | - Jong-Hyeon Kim
- Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Korea
| | - Hye-Sun Kim
- Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Korea
| | - Wongi Seol
- InAm Neuroscience Research Center, Wonkwang University, Sanbon Hospital, Gunpo, Korea
| | - Sangdun Choi
- Department of Molecular Science and Technology, Ajou University School of Medicine, Suwon, Korea
| | - Ilo Jou
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea
- Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Korea
- Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea
| | - Eun-Young Kim
- Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Korea
- Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea
- Institute for Medical Sciences, Ajou University School of Medicine, Suwon, Korea
| | - Eun-hye Joe
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea
- Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Korea
- Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea
- * E-mail:
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Kim SR, Chung ES, Bok E, Baik HH, Chung YC, Won SY, Joe E, Kim TH, Kim SS, Jin MY, Choi SH, Jin BK. Prothrombin kringle-2 induces death of mesencephalic dopaminergic neurons in vivo and in vitro via microglial activation. J Neurosci Res 2010; 88:1537-48. [PMID: 20025058 DOI: 10.1002/jnr.22318] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We have shown that prothrombin kringle-2 (pKr-2), a domain of human prothrombin distinct from thrombin could activate cultured rat brain microglia in vitro. However, little is known whether pKr-2-induced microglial activation could cause neurotoxicity on dopaminergic (DA) neurons in vivo. To address this question, pKr-2 was injected into the rat substantia nigra (SN). Tyrosine hydroxylase (TH) immunohistochemistry experiments demonstrate significant loss of DA neurons seven days after injection of pKr-2. In parallel, pKr-2-activated microglia were detected in the SN with OX-42 and OX-6 immunohistochemistry. Reverse transcription PCR and double-label immunohistochemistry revealed that activated microglia in vivo exhibit early and transient expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and several proinflammatory cytokines. The pKr-2-induced loss of SN DA neurons was partially inhibited by the NOS inhibitor N(G)-nitro-L-arginine methyl ester hydrochloride, and the COX-2 inhibitor DuP-697. Extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinase and p38 mitogen-activated protein kinase were activated in the SN as early as 1 hr after pKr-2 injection, and localized within microglia. Inhibition of these kinases led to attenuation of mRNA expression of iNOS, COX-2 and several proinflammatory cytokines, and rescue of DA neurons in the SN. Intriguingly, following treatment with pKr-2 in vitro, neurotoxicity was detected exclusively in co-cultures of mesencephalic neurons and microglia, but not microglia-free neuron-enriched mesencephalic cultures, indicating that microglia are required for pKr-2 neurotoxicity. Our results strongly suggest that microglia activated by endogenous compound(s), such as pKr-2, are implicated in the DA neuronal cell death in the SN.
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Affiliation(s)
- Sang Ryong Kim
- Brain Disease Research Center, Ajou University School of Medicine, Suwon, Korea
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13
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Park GH, Jeon SJ, Ko HM, Ryu JR, Lee JM, Kim HY, Han SH, Kang YS, Park SH, Shin CY, Ko KH. Activation of microglial cells via protease-activated receptor 2 mediates neuronal cell death in cultured rat primary neuron. Nitric Oxide 2010; 22:18-29. [DOI: 10.1016/j.niox.2009.10.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 10/06/2009] [Accepted: 10/22/2009] [Indexed: 11/30/2022]
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14
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Anti-inflammatory effect of a human prothrombin fragment-2-derived peptide, NSA9, in EOC2 microglia. Biochem Biophys Res Commun 2008; 368:779-85. [DOI: 10.1016/j.bbrc.2008.01.142] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Accepted: 01/30/2008] [Indexed: 12/14/2022]
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15
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Yang MS, Min KJ, Joe E. Multiple mechanisms that prevent excessive brain inflammation. J Neurosci Res 2007; 85:2298-305. [PMID: 17348044 DOI: 10.1002/jnr.21254] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Inflammation of the injured brain has a double-edged effect. Inflammation protects the brain from infection, but it aggravates injury. Furthermore, brain inflammation is considered a risk factor for neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases. Emerging evidence supports the activation of negative regulatory mechanisms during this process to prevent prolonged and extensive inflammation. The inflammatory stimulators themselves or products of inflammatory cells may induce the expression of negative feedback regulators, such as suppressor of cytokine signaling (SOCS)-family proteins, antioxidant enzymes, and antiinflammatory cytokines. Furthermore, death of activated microglia (major inflammatory cells in the brain) may regulate brain inflammation. Astrocytes, the most abundant cells in the brain, may also act in preventing microglial overactivation. Therefore, we propose that the extent and duration of brain inflammation is tightly regulated through the cooperation of multiple mechanisms to maximize antipathogenic effects and minimize tissue damage.
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Affiliation(s)
- Myung-Soon Yang
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Kyunggi-do, Korea
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16
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Lee KH, Yun SJ, Nam KN, Gho YS, Lee EH. Activation of microglial cells by ceruloplasmin. Brain Res 2007; 1171:1-8. [PMID: 17727827 DOI: 10.1016/j.brainres.2007.07.053] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 07/26/2007] [Accepted: 07/31/2007] [Indexed: 12/20/2022]
Abstract
Ceruloplasmin (Cp) is the major copper transport protein in plasma and catalyzes the conversion of toxic ferrous iron to the safer ferric iron. As an acute-phase protein, Cp is induced during inflammation. It is synthesized primarily in the liver and is expressed in several other tissues, including the brain. Elevated Cp levels have been observed in the brain of patients with neurodegenerative conditions, including Alzheimer's, Parkinson's, and Huntington's diseases. However, the exact role(s) of Cp in inflammatory and neuropathological conditions remains unclear. Microglia are the prime effector cells involved in immune and inflammatory responses in the central nervous system (CNS). They are activated during pathological conditions to restore CNS homeostasis, but chronic microglial activation endangers neuronal survival. Consequently, it is important to identify the regulators of microglial activation and the underlying mechanisms. We sought to examine whether Cp might modulate microglial activation. We observed that Cp induced nitric oxide (NO) release and inducible NO synthase mRNA expression in BV2 microglial cells and rat brain microglia. Cp also increased levels of mRNAs encoding tumor necrosis factor-alpha, interleukin-1beta, cyclooxygenase-2, and NADPH oxidase. Treatment of BV2 cells and primary microglia with Cp induced phosphorylation of p38 MAP kinase. Moreover, Cp induced nuclear factor (NF)-kappaB activation, showing a more sustained pattern than seen with bacterial lipopolysaccharide. Cp-stimulated NO induction was significantly attenuated by a p38 inhibitor, SB203580, and the NF-kappaB inhibitor SN50. Cp induced secretion of TNF-alpha and prostaglandin E(2) in primary microglial cultures. These results suggest that Cp may play an important role in neuropathological conditions by stimulating various proinflammatory and neurotoxic molecules in microglia.
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Affiliation(s)
- Kyung-Hee Lee
- Department of Medical Science, Graduate School of East-West Medical Science, Kyung Hee University, Yongin-Si, Republic of Korea
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17
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Choi HB, Ryu JK, Kim SU, McLarnon JG. Modulation of the purinergic P2X7 receptor attenuates lipopolysaccharide-mediated microglial activation and neuronal damage in inflamed brain. J Neurosci 2007; 27:4957-68. [PMID: 17475804 PMCID: PMC6672082 DOI: 10.1523/jneurosci.5417-06.2007] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Revised: 03/13/2007] [Accepted: 03/28/2007] [Indexed: 12/30/2022] Open
Abstract
We investigated the involvement and roles of the ionotropic purinergic receptor P2X(7)R in microglia in mediating lipopolysaccharide (LPS)-induced inflammatory responses and neuronal damage in rat striatum. A detailed in vivo study showed that LPS injection into striatum markedly increased the expression of P2X(7)R in microglia compared with control (saline)-injected animals. Additionally, LPS injection upregulated a broad spectrum of proinflammatory mediators, including inducible nitric oxide synthase (nitric oxide production marker), 3-nitrotyrosine (peroxynitrite-mediated nitration marker), 4-hydroxynonenal (lipid peroxidation marker), and 8-hydroxy-2'-deoxyguanosine (oxidative DNA damage marker), and reduced neuronal viability. The P2X(7)R antagonist oxidized ATP (oxATP) was effective in attenuating expressions of all inflammatory mediators and in addition inhibited LPS-induced activation of the cellular signaling factors p38 mitogen-activated protein kinase and transcriptional factor nuclear factor kappaB. Most importantly, in vivo, oxATP blockade of P2X(7)R also reduced numbers of caspase-3-positive neurons and increased neuronal survival in LPS-injected brain. In vitro, LPS stimulation of cultured human microglia enhanced cellular expressions of a host of proinflammatory factors, including cyclooxygenase-2, interleukin-1beta (IL-1beta), IL-6, IL-12, and tumor necrosis factor-alpha; all factors were inhibited by oxATP. A novel finding was that LPS potentiated intracellular [Ca(2+)](i) mobilization induced by the P2X(7)R ligand 2',3'-O-(4-benzoyl-benzoyl) ATP, which could serve as a mechanistic link for P2X(7)R amplification of inflammatory responses. Our results suggest critical roles for P2X(7)R in mediating inflammation and inhibition of this subtype purinergic receptor as a novel therapeutic approach to reduce microglial activation and confer neuroprotection in inflamed and diseased brain.
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Affiliation(s)
- Hyun B. Choi
- Department of Anesthesiology, Pharmacology, and Therapeutics and
- Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3, and
| | - Jae K. Ryu
- Department of Anesthesiology, Pharmacology, and Therapeutics and
| | - Seung U. Kim
- Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3, and
- Brain Disease Research Center, Ajou University, Suwon, Korea 443-749
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18
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Yang MS, Ji KA, Jeon SB, Jin BK, Kim SU, Jou I, Joe E. Interleukin-13 enhances cyclooxygenase-2 expression in activated rat brain microglia: implications for death of activated microglia. THE JOURNAL OF IMMUNOLOGY 2006; 177:1323-9. [PMID: 16818793 DOI: 10.4049/jimmunol.177.2.1323] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Brain inflammation has recently attracted widespread interest because it is a risk factor for the onset and progression of brain diseases. In this study, we report that cyclooxygenase-2 (COX-2) plays a key role in the resolution of brain inflammation by inducing the death of microglia. We previously reported that IL-13, an anti-inflammatory cytokine, induced the death of activated microglia. These results revealed that IL-13 significantly enhanced COX-2 expression and production of PGE(2) and 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)) in LPS-treated microglia. Two other anti-inflammatory cytokines, IL-10 and TGF-beta, neither induced microglial death nor enhanced COX-2 expression or PGE(2) or 15d-PGJ(2) production. Therefore, we hypothesized that the effect of IL-13 on COX-2 expression may be linked to death of activated microglia. We found that COX-2 inhibitors (celecoxib and NS398) suppressed the death of microglia induced by a combination of LPS and IL-13 and that exogenous addition of PGE(2) and 15d-PGJ(2) induced microglial death. Agonists of EP2 (butaprost) and peroxisome proliferator-activated receptor gamma (ciglitazone) mimicked the effect of PGE(2) and 15d-PGJ(2), and an EP2 antagonist (AH6809) and a peroxisome proliferator-activated receptor gamma antagonist (GW9662) suppressed microglial death induced by LPS in combination with IL-13. In addition, IL-13 potentiated LPS-induced activation of JNK, and the JNK inhibitor SP600125 suppressed the enhancement of COX-2 expression and attenuated microglial death. Taken together, these results suggest that IL-13 enhanced COX-2 expression in LPS-treated microglia through the enhancement of JNK activation. Furthermore, COX-2 products, PGE(2) and 15d-PGJ(2), caused microglial death, which terminates brain inflammation.
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Affiliation(s)
- Myung-Soon Yang
- Department of Pharmacology, Ajou University School of Medicine, Suwon 442-721, Korea
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19
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Nakajima K, Matsushita Y, Tohyama Y, Kohsaka S, Kurihara T. Differential suppression of endotoxin-inducible inflammatory cytokines by nuclear factor kappa B (NFκB) inhibitor in rat microglia. Neurosci Lett 2006; 401:199-202. [PMID: 16580131 DOI: 10.1016/j.neulet.2006.03.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Revised: 03/07/2006] [Accepted: 03/08/2006] [Indexed: 11/20/2022]
Abstract
The molecular mechanism by which the deleterious cytokines interleukin 1 beta (IL-1beta) and tumor necrosis factor alpha (TNFalpha) are induced in endotoxin-stimulated microglia was investigated from the viewpoint of signal transduction. Neither cytokine is produced in nonstimulated rat microglia, but both are remarkably induced by stimulation with endotoxin lipopolysaccharide (LPS). LPS-inducible IL-1beta was significantly suppressed by pretreatment with the nuclear factor kappa B (NFkappaB) inhibitor ammonium pyrrolidine dithiocarbamate (APDC), but TNFalpha was not. APDC was actually confirmed to suppress the degradation of IkappaBalpha and IkappaBbeta in microglia, indicating a role for the inhibitor of NFkappaB activation. Taken together, these results suggest that the induction of IL-1beta and TNFalpha in endotoxin-stimulated microglia is differentially regulated at the level of NFkappaB activation.
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Affiliation(s)
- Kazuyuki Nakajima
- Department of Bioinformatics, Faculty of Engineering, Soka University, Hachioji, Tokyo 192-8577, Japan.
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20
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Uesugi M, Nakajima K, Tohyama Y, Kohsaka S, Kurihara T. Nonparticipation of nuclear factor kappa B (NFkappaB) in the signaling cascade of c-Jun N-terminal kinase (JNK)- and p38 mitogen-activated protein kinase (p38MAPK)-dependent tumor necrosis factor alpha (TNFalpha) induction in lipopolysaccharide (LPS)-stimulated microglia. Brain Res 2006; 1073-1074:48-59. [PMID: 16457791 DOI: 10.1016/j.brainres.2005.12.043] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2005] [Revised: 11/19/2005] [Accepted: 12/11/2005] [Indexed: 10/25/2022]
Abstract
The molecular mechanism of cytotoxic cytokine tumor necrosis factor alpha (TNFalpha) induction in microglia remains to be clarified. We have previously reported that p38 mitogen-activated protein kinase (p38MAPK) is an important signaling molecule for the induction of TNFalpha in lipopolysaccharide (LPS)-stimulated microglia. Recently, we have shown that c-Jun N-terminal kinase (JNK) is associated with the induction of TNFalpha. Furthermore, using an NFkappaB inhibitor (SN50), we discovered that activation of nuclear factor kappaB (NFkappaB) may also be linked to TNFalpha induction. We therefore examined the relationship between NFkappaB and the two MAPKs (p38MAPK and JNK) in the signaling cascade of TNFalpha induction in LPS-stimulated microglia. NFkappaB inhibitor SN50 decreased the induction of TNFalpha under the suppressed NFkappaB activation. However, SN50 was found to prevent the activation of MKK3/6-p38MAPK and MKK4-JNK pathways. On the other hand, the other NFkappaB inhibitor ammonium pyrrolidine dithiocarbamate (APDC) neither prevented the activation of p38MAPK and JNK nor inhibited TNFalpha induction in LPS-stimulated microglia, although it was confirmed to serve as an NFkappaB inhibitor. These results suggest that both MKK3/6-p38MAPK and MKK4-JNK pathways are important signaling cascades leading to the induction of TNFalpha in LPS-stimulated microglia, but that NFkappaB itself is not required for this induction.
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Affiliation(s)
- Miyuki Uesugi
- Neurobiology Lab, Department of Bioinformatics, Faculty of Engineering, Soka University, Hachioji, Tokyo 192-8577, Japan
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21
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Kang KY, Kim SG, Kim WK, You HK, Kim YJ, Lee JH, Jung KH, Kim CW. Purification and characterization of a recombinant anti-angiogenic kringle fragment expressed in Escherichia coli: Purification and characterization of a tri-kringle fragment from human apolipoprotein (a) (kringle IV (9)–kringle IV (10)–kringle V). Protein Expr Purif 2006; 45:216-25. [PMID: 16260151 DOI: 10.1016/j.pep.2005.08.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2005] [Revised: 08/13/2005] [Accepted: 08/19/2005] [Indexed: 11/28/2022]
Abstract
A kringle fragment (type IV (9)-IV (10)-V) from human apolipoprotein (a) (called LK68) was expressed in an inclusion body in Escherichia coli. The LK68 in this inclusion body was rendered soluble with urea, and efficiently refolded via oxidation in the presence of re-dox couple. The refolded LK68 was then purified via two steps of ion exchange chromatography, concentrated via preparative reversed-phase chromatography, and freeze-dried, at a final yield of approximately 30%. The purified LK68 exhibited profound affinity for lysine and fibrinogen, which suggests the proper folding of the kringle fragment, and also indicates that the native characteristics of apolipoprotein (a) were preserved. The purified LK68 was determined to be highly homogeneous upon reversed-phase HPLC analysis and size-exclusion HPLC analysis, in the presence of 20% (v/v) acetonitrile. However, on size-exclusion HPLC analysis without acetonitrile, it was determined to be somewhat heterogeneous, and this was corroborated by native analyses, including native PAGE and IEF.
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Affiliation(s)
- Kwan-Yub Kang
- Laboratory of Pharmaceutical Technology, Mogam Biotechnology Research Institute, 341, Pojung-ri, Guseong-eup, Yongin-city, Kyonggi-do 449-913, South Korea
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22
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Lee J, Shin S, Teng CH, Hong SJ, Kim KS. FimH adhesin of Escherichia coli K1 type 1 fimbriae activates BV-2 microglia. Biochem Biophys Res Commun 2005; 334:917-23. [PMID: 16036224 DOI: 10.1016/j.bbrc.2005.06.180] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2005] [Accepted: 06/27/2005] [Indexed: 11/17/2022]
Abstract
The generation of intense inflammation in the subarachnoid space in response to meningitis-causing bacteria contributes to brain dysfunction and neuronal injury in bacterial meningitis. Microglia, the major immune effector cells in the central nervous system (CNS), become activated by bacterial components to produce proinflammatory immune mediators. In this study, we showed that FimH adhesin, a tip component of type 1 fimbriae of meningitis-causing Escherichia coli K1, activated the murine microglial cell line, BV-2, which resulted in the production of nitric oxide and the release of tumor necrosis factor-alpha. Mitogen-activated protein kinases, ERK and p-38, and nuclear factor-kappaB were involved in FimH adhesin-mediated microglial activation. These findings suggest that FimH adhesin contributes to the CNS inflammatory response by virtue of activating microglia in E. coli meningitis.
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Affiliation(s)
- Jongseok Lee
- Division of Pediatric Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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23
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Lee DY, Oh YJ, Jin BK. Thrombin-activated microglia contribute to death of dopaminergic neurons in rat mesencephalic cultures: dual roles of mitogen-activated protein kinase signaling pathways. Glia 2005; 51:98-110. [PMID: 15789435 DOI: 10.1002/glia.20190] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
This study evaluated the role of thrombin-activated microglia in the neurodegeneration of mesencephalic cultures. Immunocytochemical and biochemical evidence indicated that in co-cultures consisting of rat cortical microglia and mesencephalic neurons, thrombin led to nonselective loss of mesencephalic neurons. Accompanying neurodegeneration, microglial activation was obvious, evidenced by expression of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-1beta, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) and by increasing production of TNF-alpha and nitric oxide (NO). In mesencephalic neurons treated with conditioned media (CM) taken from thrombin-activated microglia, the number of dopaminergic neurons was significantly attenuated. The neurotoxicity of the CM was diminished when it was derived from microglia co-treated with thrombin and either an extracellular signal-regulated kinase 1/2 (ERK1/2) pathway inhibitor (PD98059) or a p38-mitogen-activated protein kinase (p38-MAPK) inhibitor (SB203580). Moreover, jun N-terminal kinase (JNK) and p38-MAPK were activated in mesencephalic neurons treated with CM of thrombin-activated microglia. Inhibition of JNK and p38-MAPK rescued the dopaminergic neurons. Collectively, these results indicate that thrombin-activated microglia induce neurodegeneration in cultured mesencephalic neurons and that the MAPKs actively participate in both microglial activation and neurodegeneration. The present data carefully suggest that microglial activation triggered by thrombin may be involved in the neuropathological processes of dopaminergic neuronal cell death that occur in Parkinson's disease.
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Affiliation(s)
- Da Yong Lee
- Brain Disease Research Center, Ajou University School of Medicine, Suwon, Korea
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24
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Sheehan JJ, Tsirka SE. Fibrin-modifying serine proteases thrombin, tPA, and plasmin in ischemic stroke: a review. Glia 2005; 50:340-350. [PMID: 15846799 DOI: 10.1002/glia.20150] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ischemic stroke is a sudden loss of circulation to a portion of the brain that results in a loss of neurologic function. Many ischemic strokes are embolic. They result from a thrombus traveling into the central circulation and occluding a blood vessel. Treatment of ischemic stroke with recombinant tissue plasminogen activator (tPA) can improve patient outcomes. However, tPA must be used during a specific time window after the stroke onset to be effective and it risks converting an ischemic stroke into a hemorrhagic one. We explore the basic effects of fibrin-modifying proteases on neurons, astrocytes, and microglia during ischemia. tPA, thrombin, and plasmin can initiate microglial activation and change both neuronal and astrocytic survival. As a result of these functions and of their role in blood homeostasis, all three of these proteases have profound effects on neurons and glial cells in the brain and are capable of altering the development and severity of ischemic stroke.
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Affiliation(s)
- John J Sheehan
- Program in Molecular and Cellular Pharmacology and Department of Pharmacological Sciences, University Medical Center at Stony Brook, Stony Brook, New York
| | - Stella E Tsirka
- Program in Molecular and Cellular Pharmacology and Department of Pharmacological Sciences, University Medical Center at Stony Brook, Stony Brook, New York
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25
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Min KJ, Pyo HK, Yang MS, Ji KA, Jou I, Joe EH. Gangliosides activate microglia via protein kinase C and NADPH oxidase. Glia 2005; 48:197-206. [PMID: 15390122 DOI: 10.1002/glia.20069] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Microglia, the major immune effector cells in the central nervous system, are activated when the brain suffers injury. A number of studies indicate that gangliosides activate microglia. However, the signaling mechanisms involved in microglial activation are not yet to be elucidated. Our results show that gangliosides induce the expression of interleukin (IL)-1beta, tumor necrosis factor-alpha (TNF-alpha), and inducible nitric oxide synthase (iNOS) in rat brain microglia and BV2 murine microglia via protein kinase C (PKC) and NADPH oxidase. Expression of IL-1beta, TNF-alpha, and iNOS in ganglioside-treated cells was significantly reduced in the presence of inhibitors of PKC (GF109203X, Go6976, Ro31-8220, and rottlerin) and NADPH oxidase (diphenyleneiodonium chloride [DPI]). In response to gangliosides, PKC-alpha, betaII, and delta and NADPH oxidase p67(phox) translocated from the cytosol to the membrane. ROS generation was also activated within 5 min of ganglioside treatment. Ganglioside-induced ROS generation was blocked by PKC inhibitors. Furthermore, ganglioside-induced activation of NF-kappaB, an essential transcription factor that mediates the expression of IL-1beta, TNF-alpha, and iNOS, was reduced in the presence of GF109203X and DPI. Our results collectively suggest that gangliosides activate microglia via PKC and NADPH oxidase, which regulate activation of NF-kappaB.
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Affiliation(s)
- Kyoung-Jin Min
- Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Korea
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26
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Hanisch UK, van Rossum D, Xie Y, Gast K, Misselwitz R, Auriola S, Goldsteins G, Koistinaho J, Kettenmann H, Möller T. The microglia-activating potential of thrombin: the protease is not involved in the induction of proinflammatory cytokines and chemokines. J Biol Chem 2004; 279:51880-7. [PMID: 15452111 DOI: 10.1074/jbc.m408318200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The serine protease thrombin is known as a blood coagulation factor. Through limited cleavage of proteinase-activated receptors it can also control growth and functions in various cell types, including neurons, astrocytes, and microglia (brain macrophages). A number of previous studies indicated that thrombin induces the release of proinflammatory cytokines and chemokines from microglial cells, suggesting another important role for the protease beyond hemostasis. In the present report, we provide evidence that this effect is not mediated by any proteolytic or non-proteolytic mechanism involving thrombin proper. Inhibition of the enzymatic thrombin activity did not affect the microglial release response. Instead the cyto-/chemokine-inducing activity solely resided in a high molecular weight protein fraction that could be isolated in trace amounts even from apparently homogenous alpha- and gamma-thrombin preparations. High molecular weight material contained thrombin-derived peptides as revealed by mass spectrometry but was devoid of thrombin-like enzymatic activity. Separated from the high molecular weight fraction by fast protein liquid chromatography, enzymatically intact alpha- and gamma-thrombin failed to trigger any release. Our findings may force a revision of the notion that thrombin itself is a direct proinflammatory release signal for microglia. In addition, they could be relevant for the study of other cellular activities and their assignment to this protease.
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Affiliation(s)
- Uwe-Karsten Hanisch
- Department of Cellular Neurosciences, Max Delbrück Center for Molecular Medicine, D-13092 Berlin, Germany.
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27
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Shin WH, Lee DY, Park KW, Kim SU, Yang MS, Joe EH, Jin BK. Microglia expressing interleukin-13 undergo cell death and contribute to neuronal survival in vivo. Glia 2004; 46:142-52. [PMID: 15042582 DOI: 10.1002/glia.10357] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
How to minimize brain inflammation is pathophysiologically important, since inflammation induced by microglial activation can exacerbate brain damage. In the present report, we show that injection of lipopolysaccharide (LPS) into the rat cortex led to increased levels of interleukin-13 (IL-13) and to IL-13 immunoreactivity, followed by the substantial loss of microglia at 3 days post-LPS. IL-13 levels in LPS-injected cortex reached a peak at 12 h post-injection, remained elevated at 24 h, and returned to basal levels at day 4. In parallel, IL-13 immunoreactivity was detected as early as 12 h post-LPS and maintained up to 24 h; it disappeared at 4 days. Surprisingly, IL-13 immunoreactivity was detected exclusively in microglia, but not in neurons or astrocytes. Following treatment with LPS in vitro, IL-13 expression was also induced in microglia in the presence of neurons, but not in the presence of astrocytes or in cultured pure microglia alone. In experiments designed to determine the involvement of IL-13 in microglia cell death, IL-13-neutralizing antibodies significantly increased survival of activated microglia at 3 days post-LPS. Consistent with these results, the expression of inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-alpha) was sustained in activated microglia and neuronal cell death was consequently increased. Taken together, the present study is the first to demonstrate the endogenous expression of IL-13 in LPS-activated microglia in vivo, and to demonstrate that neurons may be required for IL-13 expression in microglia. Our data strongly suggest that IL-13 may control brain inflammation by inducing the death of activated microglia in vivo, resulting in an enhancement of neuronal survival.
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Affiliation(s)
- Won Ho Shin
- Brain Disease Research Center, Ajou University School of Medicine, Suwon, Korea
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Min KJ, Jou I, Joe E. Plasminogen-induced IL-1beta and TNF-alpha production in microglia is regulated by reactive oxygen species. Biochem Biophys Res Commun 2004; 312:969-74. [PMID: 14651966 DOI: 10.1016/j.bbrc.2003.11.010] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microglia, major immune effector cells in the central nervous system, become activated during brain injury. In this study we showed that the blood component plasminogen/plasmin activates microglia. Plasminogen-induced IL-1beta, TNF-alpha, and iNOS mRNA expression in primary cultured rat microglia and BV2 murine microglial cells. Plasmin caused a similar response. Serine protease inhibitors suppressed both plasminogen- and plasmin-induced IL-1beta and TNF-alpha expression, indicating the importance of serine protease activity in plasminogen/plasmin activation of microglia. Reactive oxygen species (ROS) appeared to play an important role in plasminogen-induced microglial activation, with ROS being generated within 15min of plasminogen treatment, and antioxidants (100 microM trolox and 10mM NAC) reducing IL-1beta and TNF-alpha expression in plasminogen-treated cells. Furthermore, plasminogen stimulated CREB and NF-kappaB DNA binding activity, and this activation was also reduced by trolox and NAC. These results suggest that plasminogen activates microglia via stimulation of ROS production.
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Affiliation(s)
- Kyoung-jin Min
- Neuroscience Graduate Program, Ajou University School of Medicine, 442-721, Suwon, South Korea
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Abstract
The present study examined whether thrombin-induced microglial activation could contribute to death of dopaminergic neurons in the rat substantia nigra (SN) in vivo. Seven days after thrombin injection into the SN, tyrosine hydroxylase immunohistochemistry showed a significant loss of nigral dopaminergic neurons. In parallel, thrombin-activated microglia, visualized by immunohistochemical staining using antibodies against the complement receptor type 3 (OX-42) and the major histocompatibility complex class II antigens were also observed in the SN, where degeneration of nigral neurons was found. Reverse transcription PCR at various time points demonstrated that activated microglia in vivo exhibited an early and transient expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and several proinflammatory cytokines, including interleukin 1beta (IL-1beta), IL-6, and tumor necrosis factor alpha. Western blot analysis and double-label immunohistochemistry showed an increase in the expression of iNOS and COX-2 and the colocalization of these proteins within microglia. The thrombin-induced loss of SN dopaminergic neurons was partially inhibited by NG-nitro-L-arginine methyl ester hydrochloride, an NOS inhibitor, and by DuP-697, a COX-2 inhibitor. Additional studies demonstrated that extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK) were activated in the SN as early as 30 min after thrombin injection, and that these kinases were localized within microglia. Inhibition of ERK1/2 and p38 MAPK reduced iNOS and COX-2 mRNA expression and rescued dopaminergic neurons in the SN. The present results strongly suggest that microglial activation triggered by endogenous compound(s) such as thrombin may be involved in the neuropathological processes of dopaminergic neuronal cell death that occur in Parkinson's disease.
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Pyo H, Yang MS, Jou I, Joe EH. Wortmannin enhances lipopolysaccharide-induced inducible nitric oxide synthase expression in microglia in the presence of astrocytes in rats. Neurosci Lett 2003; 346:141-4. [PMID: 12853104 DOI: 10.1016/s0304-3940(03)00505-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Microglia, the primary inflammatory cells in the brain, are activated upon brain injury. Activated microglia produce nitric oxide (NO), a major toxin to neuronal cells. It has been reported that astrocytes inhibit microglial activation. In this study, we found that wortmannin, a natural inhibitor of phosphatidylinositol 3-kinase, significantly increased lipopolysaccharide (LPS)-induced NO release and inducible nitric oxide synthase (iNOS) expression in microglia in the presence but not in the absence of astrocytes. In response to LPS even in the presence of wortmannin, iNOS immunoreactivity was detected in microglia but not in astrocytes. These results suggest that astrocytes could regulate microglia-mediated brain inflammation by inhibiting microglial NO release/iNOS expression via a wortmannin-sensitive mechanism.
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Affiliation(s)
- Hankyoung Pyo
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Kyunggi-do, 442-721, South Korea
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